Abstract:Polyketides (PKs) and non-ribosomal peptides are the most important drug-leads for human, animal, and plant diseases. The conserved modular architectures and biosynthetic assembly line of polyketide synthases (PKS) and non-ribosomal peptide synthases (NRPS) endow PKs and NRPs with extremely diverse structures and activities and bring infinite possibilities to edit and modify the backbone structure of PKs and NRPs by adding, removing, inactivating and replacing PKS/NRPS modules or domains. The biosynthetic machinery of microbial polyketide natural products has evolved delicately with specific recognition and efficient catalysis of upstream intermediates by downstream enzymes/domains. Therefore, manipulations of PKS/NRPS and their related tailoring enzymes usually lead to attenuated production or abolished accumulation of intermediates with modified structures. As the terminal domain of most PKS and NRPS, thioesterases (TEs) play crucial roles in substrate selection during the chain release of these bioactive natural products, serving as pivotal bottleneck steps in their late-stage biosynthesis. TEs mainly perform chain hydrolysis or ester transfer reactions by nucleophilic attack of foreign nucleophiles such as H₂O. Meanwhile, TEs also undergo nucleophilic attack by intramolecular oxygen atom, nitrogen atom, or carbon atom to achieve macrolactonization, macrolactamization, or Claisen condensation, respectively. There are two main classes of TEs involved in natural product biosynthesis. Type I TEs (TEIs) are commonly found in type I cis-AT PKS, trans-AT PKS, NRPS, and fungal PKS/NRPS, which are mainly located at the end module of synthase. In addition to TEIs, there is also a class of free type II TE (TEIIs), which catalyzes the release of incomplete or incorrectly extended intermediates during PKs and NRPs biosynthesis. Besides, a distinct class of free TE was identified in the chain release of polyether backbones, such as monensin and nanchangmycin. Since 2001, more than 20 crystal structures of TEs from diverse PKSs and NRPSs have been solved. The structural elucidation of TEs has unlocked the mystery of their structural and functional interaction, laid the foundation for the TE classification and mechanistic insight into the substrate selectivity and catalytic efficiency of TE, which further promotes the understanding of the chain release mechanism of natural products and better served the rational design of TE. Previous articles have systematically reviewed the structure, function, and regulatory mechanism of different TE families. Horsman et al. also reviewed the diversity, structure, and mechanism of TEs in PKSs and NRPSs. They put forward an insightful view that TEs might act as logic gates for substrate loading and chain releasing during the biosynthesis of natural products. It provides an important perspective for studying the evolution and functional prediction of TEs. This review summarizes the structural characteristics of various TE, focusing on the structural consistency of thioesterase to the catalytic mechanism. Additionally, this review follows the progress and limitations on the catalytic mechanism and computational simulation of type I TE, providing a detailed analysis of the chemical essence of thioesterase-catalyzed chain release reactions. This review aims to deliver revealing suggestions for the structural elucidation and mechanistic insights of TE, as well as its rational design for improved chain release of unnatural products.

Abstract:Tripartite motif-containing protein 13 (TRIM13) is a crucial member of the TRIM protein family, distinguished by its unique transmembrane domain that anchors it to the endoplasmic reticulum (ER). As an E3 ubiquitin ligase, TRIM13 influences multiple key signaling pathways through ubiquitination regulation, playing significant roles in modulating ER function, immune responses, metabolic disorders, inflammatory diseases, and tumor suppression. TRIM13 possesses the common RING, B-box, and coiled-coil domains of the TRIM family, along with its distinctive transmembrane domain. Its E3 ubiquitin ligase activity serves as the structural basis for its diverse biological functions. TRIM13 acts as a non-canonical ER-phagy receptor to participate in regulating ER stress responses, recruiting LC3 through interaction with SQSTM1/p62 to initiate autophagy-mediated degradation of damaged ER, which is crucial for maintaining ER homeostasis and cellular function under stress conditions. TRIM13 is involved in inflammatory and antiviral immune responses by modulating key molecules in signaling pathways such as MDA5, NF-κB, and STING, highlighting its potential in regulating innate immunity and inflammatory responses. TRIM13 is associated with various pathological conditions, particularly in cancer and metabolic diseases. In multiple cancers, including non-small cell lung cancer, hepatocellular carcinoma, and acute myeloid leukemia, TRIM13 exhibits tumor-suppressive effects, with its expression levels closely associated with patient prognosis, suggesting its potential as a biomarker or therapeutic target in oncology. In diabetic nephropathy, TRIM13 improves renal function by promoting CHOP ubiquitination and inhibiting interstitial collagen synthesis, demonstrating its protective role in kidney disease. In atherosclerosis, TRIM13 is involved in regulating cholesterol metabolism and inflammatory pathways, indicating its significance in cardiovascular disorders. Recent studies have also implicated TRIM13 in neurodegenerative disorders and metabolic syndromes, with its role in regulating protein quality control and ER stress responses, suggesting potential involvement in diseases characterized by protein misfolding and aggregation, such as Alzheimer’s and Parkinson’s diseases. Additionally, TRIM13’s participation in lipid metabolism and insulin signaling pathways points to its possible influence on obesity and diabetes. Despite significant advancements in TRIM13 research, the precise molecular mechanisms underlying its functions in various physiological and pathological processes remain to be elucidated. In this article, we review the structural characteristics and functions of TRIM13 protein, with particular emphasis on its roles in ER-phagy, inflammatory responses, and tumor suppression, as well as its potential significance in various diseases. Future studies should focus on revealing the specific core mechanisms of TRIM13 function and exploring its unique role in ER function regulation. A deeper understanding of TRIM13 protein and its regulatory mechanisms in development of diseases may provide novel targets and strategies for disease diagnosis and treatment.

Abstract:Alzheimer’s disease (AD) is the most common form of dementia, and its prevalence is rapidly increasing with the aging population. Among the growing number of genetic risk factors, apolipoprotein E (ApoE) is the most prevalent and strongest risk factor, accounting for nearly three-quarters of AD cases. ApoE is a key protein involved in lipids and cholesterol metabolism in the central nervous system. There are three subtypes of ApoE: ApoE2, ApoE3, and ApoE4, among which ApoE4 is a high-risk factor for the incidence of AD. ApoE4 not only affects lipid efflux and distribution in glial cells, but also affects the lipid metabolism in neurons, resulting in the imbalance of lipid homeostasis. ApoE plays a role in the processing of amyloid precursor protein (APP), which is associated with the early production of amyloid β-(Aβ) protein and plaque deposition. ApoE4 also reduces the solubility of Tau protein, which contributes to promoting the aberrant phosphorylation and the aggregation of Tau, and resulting in neurofibrillary tangles (NFTs). Moreover, brain regions expressing ApoE4 are more susceptible to Tau diffusion. Furthermore, ApoE4 has been demonstrated to activate the NF-κB inflammatory pathway, convert microglia and astrocytes into the pro-inflammatory phenotypes, secrete pro-inflammatory factors and oxidative mediators, and induce neuroinflammation. Altogether, ApoE participates in AD neuropathology through multiple pathways such as Aβ plaque, Tau pathology, neuroinflammation, neuroplasticity and blood-brain barrier, which all jointly promotes the progression of the disease. It has been demonstrated that anti-ApoE4 antibodies can reduce the formation of Aβ plaques and neuroinflammation. The repurposing of metformin, rapamycin, enoxaparin, DHA, and tamoxifen have been shown to reduce the expression of ApoE4 protein and ameliorate AD pathology. Gene therapies utilising antisense oligonucleotides (ASO) and double-stranded interfering small RNA (siRNA) has been proved to be effective technologies to reduce ApoE4 expression and mitigate AD pathology. Adeno-associated virus (AAV)-mediated ApoE2 has been demonstrated to neutralize the negative effects of ApoE4 by expressing ApoE2 in the ventricular membrane. Traditional Chinese medicine resveratrol and waterside delivered by ApoE-modified liposome nanodrug delivery system can improve the BBB penetration of drugs and provid a new method for the treatment of AD. In addition, targeting the interaction of ApoE with low-density lipoprotein receptor (LDLR) and low density lipoprotein-related protein 1 (LRP1) receptors can indirectly regulate the expression level of ApoE, which provids a new perspective for the treatment of AD. This article aims to elucidate the roles of ApoE and its isoforms in the pathogenesis of AD and summarize the potential therapeutic strategies against ApoE with the hope of providing novel insights for the ApoE-based therapies combat AD.

Abstract:Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS) characterized by progressive demyelination and neuroinflammation, leading to axonal damage and neuronal degeneration. It is the most prevalent non-traumatic cause of neurological disability in young adults, affecting millions of people worldwide. MS manifests with a wide range of symptoms, including motor dysfunction, sensory deficits, and cognitive impairment, which can severely impact the quality of life. Despite extensive research, the exact pathogenesis of MS remains unclear, and currently available treatments primarily focus on reducing inflammation and relapse rates rather than reversing neurological damage. Thus, one of the major therapeutic challenges is to develop strategies that can not only suppress the aberrant immune response but also enhance endogenous myelin regeneration and neurorepair, ultimately halting or even reversing disease progression. Recent studies have highlighted the critical role of chondroitin sulfate proteoglycans (CSPGs), a family of inhibitory extracellular matrix (ECM) molecules, in regulating CNS repair processes. CSPGs accumulate at the sites of demyelinated lesions and form a dense, inhibitory matrix that impedes the migration and differentiation of oligodendrocyte precursor cells (OPCs), thereby preventing effective myelin regeneration. CSPGs exert their inhibitory effects through several cell surface receptors, including leukocyte common antigen-related receptor (LAR), Nogo receptors (NgR1 and NgR3), and protein tyrosine phosphatase σ (PTPσ). Among these, PTPσ is a predominant receptor that mediates the biological activities of CSPGs via its phosphatase domains, which regulate downstream signaling pathways involved in cell proliferation, differentiation, and cytoskeletal organization. The CSPGs/PTPσ axis has been identified as a major molecular pathway contributing to the inhibition of remyelination in MS. The upregulation of CSPGs and PTPσ in MS lesions has been associated with a failure of OPCs to remyelinate damaged axons effectively. Preclinical studies have shown that pharmacological inhibition or genetic ablation of PTPσ can alleviate the inhibitory effects of CSPGs on OPC migration and differentiation. For instance, systemic administration of the PTPσ inhibiting peptide intracellular sigma peptide (ISP) has been shown to enhance OPC differentiation, promote remyelination, and restore motor function in animal models of MS, highlighting the potential of targeting CSPGs/PTPσ as a therapeutic approach for MS. Furthermore, CSPGs and their receptors have been implicated in modulating other biological processes such as immune cell infiltration, synaptic plasticity, and axonal regeneration, which are relevant to the pathogenesis of MS and other neurodegenerative diseases. CSPGs are known to activate downstream signaling pathways, such as the Rho/ROCK, Akt, and ERK pathways, which regulate cytoskeletal dynamics and gene expression in OPCs, ultimately affecting their ability to mature into myelinating oligodendrocytes. Additionally, CSPGs can interact with the N-cadherin/β-catenin pathway, influencing cell adhesion and signaling in OPCs, thereby modulating myelin repair capacity. Given the multifaceted roles of CSPGs/PTPσ in CNS pathology, targeting this pathway represents a promising therapeutic strategy. This article aims to provide a comprehensive overview of the biological properties of CSPGs and PTPσ, focusing on their roles in the inhibition of myelin regeneration. Specifically, it discusses how CSPGs/PTPσ signaling modulates various aspects of OPC biology, including autophagy regulation and immune modulation. Moreover, the review explores potential therapeutic strategies aimed at disrupting CSPGs/PTPσ interactions, such as the use of small-molecule inhibitors, neutralizing antibodies, or gene therapies. In summary, a deeper understanding of CSPGs/PTPσ-mediated signaling in OPCs and other cell types within MS lesions may reveal novel therapeutic targets for promoting remyelination and functional recovery. This review provides a detailed analysis of current findings and highlights the need for further research to translate these findings into effective treatments for MS patients.

Abstract:Drug addiction is a worldwide issue that threaten social stability and development. It has been proved to be a chronic, relapsing disease that results from the prolonged effects of drugs on the various neural networks. Over time, plenty of attention has been paid to find new approaches to enhance the sensitivity and accuracy of assessment on addiction. In recent years, researchers found that the expression of neurotransmitters and their receptors in some peripheral blood immunocyte may reflect their expression in the brain. By analyzing the changes of addiction-related neural biomarkers in peripheral blood immunocyte, it is potential to enhance the accuracy and the susceptibility of assessments on addiction and treatment effectiveness, and in turn help to reduce drug relapse. In this review, we summarize the potential biomarkers related to addiction in peripheral blood immunocyte and changing trend of their mRNA expression level in patients using different types of drugs and with different addiction states, and discuss their application prospects and future research directions. Previous studies have found various types of potential addiction biomarkers, including neurotransmitter receptor proteins, hormones, small molecule metabolites, ΔFosB microRNA and other transcriptional (post) regulators. Considering the correlation with addiction and the richness of existing research, this article mainly introduces neurotransmitter receptor proteins closely related to addiction, including dopamine receptors, opioid receptors, cannabinoid receptors, and N-methyl-D-aspartate (NMDA) receptors. The expression levels of these potential biomarkers often change correspondingly at different stages. For example, mRNA expression of dopamine D3 receptor was increased in opioid addicted and methadone-maintained patients, but no change was observed in the heroin abstinent group. In addition, changing patterns of the biomarkers induced by different types of drugs were also various. Although both opioid addiction and alcohol addiction could induce the change of mRNA expression of dopamine D4 receptor, it was decreased in the opioid addiction patients while increased in the alcohol addiction patients. On the basis of the available evidence, dopamine receptors (especially D4 receptors) are most potent at the indicative action across drugs and stages, while cannabinoid receptors mainly specifically reflect different stages of cannabis addiction status. In addition, the mRNA level of the GluN3B subunit showed a steady increase in different stages of opioid addiction and showed a decreased response to methadone treatment, suggesting that it has high potential as a biomarker of heroin addiction. Besides, the mRNA level of D4 receptor showed a clear reverse trend in the stage of alcohol addiction and alcohol withdrawal, which also reflected the potential of D4 receptor mRNA in the state of alcohol addiction. Considering evidences about serum levels changing in patients with drug addiction, immune response induced by drugs may be one possible mechanism of changes in the expression levels of transmitter receptors in the peripheral blood of drug addiction patients. Finally, the current research on biomarkers in peripheral blood for addiction is still relatively fragmented, and lack systematic mechanism exploration. Future studies could further combine animal studies and clinical studies to systematically demonstrate the role of relevant biomarkers and underlying mechanisms. In addition, there are often interactions between multiple biomarker proteins in mediating drug addiction, especially in the process of addiction development. Thus, the overall observation of the dynamic changing of different biomarkers in the addiction process may be helpful to enhance the accuracy of assessment of addiction states. At the same time, when applying peripheral blood biomarkers, corresponding standards should be formulated based on experimental evidences, so as to enhance the pertinence and effectiveness of peripheral blood biomarkers in the diagnosis and treatment of addiction.

Abstract:In recent years, tumor-infiltrating B lymphocytes (TIL-B) play a complex and important role in tumorigenesis and tumor development. TIL-B contains various subpopulations, which can be broadly classified into subpopulations of tumor-suppressing B cells, such as antigen-presenting B cells and plasma cells; and subpopulations of tumor-promoting B cells, such as regulatory B cells (Bregs). The anti-tumor mechanisms of TIL-B contain many aspects, including the secretion of specific antibodies such as IgG and IgA; activation of T cells through antigen presentation; release of cytokines that affect tumor cell growth; direct killing of target cells through the Fas/FasL and perforin pathways; and enhancement of anti-tumor immunity through interactions with T cells. The pro-tumor mechanism of TIL-B also includes many aspects, such as Bregs can inhibit anti-tumor immunity by secreting cytokines, inducing the production of regulatory T cells (Tregs), and inhibiting the interaction between T cells and antigen presenting cells (APCs). Atypical memory (AtM) B cells and leucine-tRNA-synthase-2 (LARS2) -expressing B cells (LARS B) can also promote tumor progression by secreting cytokines such as TNF-α and TGF-β. Based on the above mechanisms, a variety of tumor therapies are now available. Firstly, the anti-tumor effect of TIL-B can be enhanced. Immune checkpoint blockade therapy is a classical immunotherapy method, and TIM-1 is a key checkpoint and has achieved certain efficacy. In addition, the development of suitable novel antibodies, safe and effective TIL-B vaccines are also promising therapeutic methods. Adoptive metastatic B-cell therapy, direct activation of B-cells, chemotherapy and targeted drugs is limited because of the high technical requirements, high toxicity and uncertainty of efficacy. In the future, it is expected that further research will gradually expand the scope of its application to achieve more effective treatment for tumor patients. Selective depletion of B cells is an immunotherapy based on the inhibition of Bregs subpopulations to achieve anti-tumor effects. The next step is to develop more efficacious targeted drugs by understanding the phenotypic and functional differences of Bregs. Finally, TIL-B can be involved in the treatment and prognosis of tumors as a predictive tumor immune marker. The efficacy of treatment can be simply assessed by observing TIL-B distribution and density in tumor. Stress-responsive memory B cells and tumor-associated atypical B cells (TAAB) have clearly shown to be associated with shorter and longer survival in cancer patients, thus being used as biomarkers of immunotherapeutic response in human cancers. This paper reviews the current status of TIL-B research, summarizes its mechanism of action in tumor immunity, analyses current therapeutic strategies and prognostic assessment methods. Future focus on understanding the functional heterogeneity and molecular regulatory mechanisms of TIL-B is essential for optimising tumor immunotherapy strategies. The systematic study of TIL-B characteristics and mechanisms of action in different tumor types can help provide a theoretical basis and potential targets for the development of new tumor therapeutic strategies.

Abstract:Aging has been identified as one of the risk factors for chronic disease, and the onset and development of many chronic diseases are closely related to gut immune dysfunction in the elderly. Aging profoundly affects the intestinal immune system and the homeostasis of intestinal flora. We have reviewed the changes in intestinal mucosal immune function that occur with aging, including Toll-like receptors (TLRs), T cells, B cells and inflammatory cytokines such as IL-6, TNF-α and IFN-γ. Age-related changes in typical gut microbiota and their metabolites were discussed. Aging leads to changes in the composition and diversity of the gut microbiota. With advancing age, intestinal bacteria such as Bacteroides, Bifidobacterium and Clostridium butyricum undergo significant alterations. These changes lead to a decline in the metabolites produced by the gut flora, including short chain fatty acids (SCFAs), bile, indole and indole derivatives. As a result, the homeostasis of the gut microbiota becomes disrupted, leading to an imbalance in the intestinal microbial ecosystem. The interaction between the intestinal flora and its metabolites and the intestinal immune system has been studied and a high correlation between the intestinal flora and the immune function of the intestinal mucosa has been proposed. Under normal circumstances, a healthy immune system and gut flora are mutually reinforcing and promote the health of the host. However, with age, the integrity of intestinal mucosa and the homeostasis of intestinal flora are disrupted, resulting in a decline in the immune response and regulatory capacity and an inability to respond effectively to various exogenous insults. Meanwhile, the ongoing damage to the immune system further exacerbates the imbalance in the gut flora. Changes in the gut flora of the elderly affect the diversity and levels of key immune molecules such as defensins and immunoglobulin A (IgA). Abnormal expression of immune molecules in the gut also leads to changes in the composition of the gut microbiome, affecting gut health and potentially increasing the risk of disease. The metabolites of intestinal flora interact with intestinal receptors, activate relevant signalling pathways, directly regulate immune cells and control the immune system, influence the intestinal barrier and intestinal immune functions, and exert immunoregulatory effects on the intestine. As the relationship between gut flora and immune aging becomes clearer, future research can explore strategies for targeted regulation of gut flora for anti-aging and immune enhancement. In this paper, we further explore the regulation of gut flora and gut immune function by dietary intervention and fecal microbiota transplantation (FMT) to achieve the goal of delaying immune aging. Dietary intervention promotes the growth of beneficial bacteria by adjusting the structure of the elderly’s diet and supplementing with microbial preparations, maintaining the intestinal barrier and reducing chronic inflammation. FMT involves the transplantation of faeces from healthy individuals into recipients to improve mucosal integrity and promote microbial diversity. This paper has discussed the complex mechanism between aging, gut flora and immune response, highlighted the research progress of gut flora anti-aging methods, with the aim of providing a reference for research on targeted gut flora regulation to promote gut mucosal immune function for health promotion and anti-aging.

Abstract:The two-component system (TCS) is a signaling mechanism extensively found in prokaryotes, playing a pivotal role in bacterial environmental sensing and adaptive responses. Comprising histidine kinase (HK) and response regulator (RR) components, TCS ensures appropriate bacterial reactions to various stimuli. Understanding its structural composition, signal transduction mechanisms, and applications in synthetic biology underscores its significance in both basic research and biotechnological applications. At its core, TCS operates through a sequence of events initiated by the detection of environmental cues. When the HK senses specific signals such as temperature changes, osmolarity shifts, or the presence of ligands, it undergoes autophosphorylation at a conserved histidine residue within its kinase domain. Subsequently, this phosphoryl group is transferred to a conserved aspartate residue on the RR’s receiver domain. This phosphotransfer event activates the RR, inducing a conformational change that alters its activity, often leading to changes in gene expression or other cellular responses. The specificity and fidelity of signal transduction in TCS are critical for bacteria to differentiate between various environmental cues and mount appropriate responses. This specificity is achieved through mechanisms such as unique signal molecule recognition by HKs and precise phosphotransfer from HKs to RRs. Moreover, the directional transfer of phosphoryl groups ensures tightly regulated signaling cascades, contributing to the overall robustness of bacterial response systems. Beyond its natural role, the versatility of TCS has been harnessed by engineers in synthetic biology to create tools like biosensors. By integrating TCS components into synthetic circuits, researchers can develop customized biosensors capable of highly sensitive and specific detection of environmental signals or biomolecules. These engineered biosensors find applications across diverse fields including environmental monitoring, medical diagnostics, and industrial biotechnology. The robustness of TCS-driven biosensors is particularly advantageous in synthetic biology. The modular design of TCS allows for the construction of sensor systems sensitive to a broad range of signals, adaptable to different cellular contexts. This adaptability is crucial for optimizing sensor performance under varying conditions, ensuring reliable and reproducible results. Safety considerations are paramount in synthetic biology, where TCS-based systems offer inherent safety features due to their reliance on natural signaling pathways and components. Well-characterized interactions between HKs and RRs minimize risks such as unintended cross-talk or interference with endogenous cellular processes, enhancing reliability in bioengineering applications requiring predictable and controllable cellular responses. Looking ahead, ongoing research aims to expand the capabilities of TCS-based biosensors through innovative engineering approaches. Advances in synthetic biology techniques, including genome editing and high-throughput screening, facilitate rapid design and optimization of novel sensor systems. These efforts promise next-generation biosensors with enhanced functionalities such as multiplexed sensing and real-time monitoring in complex biological environments. In summary, the TCS stands as a cornerstone of bacterial signal transduction, facilitating precise environmental sensing and adaptive responses. Its structural simplicity, coupled with robust signaling mechanisms and programmability, underpins its utility in synthetic biology for developing advanced biosensors and other bioengineering applications. By leveraging these capabilities, researchers are poised to address critical challenges in healthcare, environmental sustainability, and industrial biotechnology, shaping the future of biologically inspired technologies.

Abstract:As the aging population in China continues to grow, the country’s public health sector faces an urgent need to address the significant social challenges posed by Alzheimer’s disease (AD). The available clinical treatments for AD are extremely limited, and the effectiveness of these drugs often diminishes after a period of use. Despite substantial global investment in drug research and development, the progress of clinical trials for AD treatments has been exceedingly slow. Over the past 30 years, only seven AD drugs have been approved by the U.S. Food and Drug Administration (FDA). Traditional drug therapies are expensive and can only slow the progression of AD, without halting the progressive degeneration of neurons. Therefore, exploring and developing emerging treatment methods for AD is imperative. Photobiomodulation (PBM) is a non-invasive therapeutic approach that uses red or near-infrared light to stimulate cellular metabolism and biological responses. PBM has the potential to improve brain metabolism and blood circulation, repair damaged neurons in the brain, and stimulate dendritic and neuronal growth, making it a promising non-invasive neurotherapeutic method that could complement drug treatments. This paper discusses the pathological characteristics and pathogenic mechanisms of AD, as well as the challenges faced by existing treatment strategies. It also reviews the research on PBM treatment in AD cellular and animal models and clinical studies, summarizes the history of phototherapy and the current state of advanced PBM phototherapy device development, and finally offers a perspective on the future development of advanced photonic technologies and therapeutic devices for PBM treatment of AD.

Abstract:In recent years, it has been discovered that innate immunity also exhibits immune memory characteristics, referred to as trained immunity. This refers to the ability of innate immune cells to acquire a memory-like capacity after being attacked by pathogens, thereby demonstrating enhanced reactivity upon secondary stimulation from the same or different stimuli. Existing research indicates that high-fat diet stimulates innate immune cells to undergo trained immunity, thereby significantly boosting their immune response to secondary metabolic disorders. This process serves as a crucial mechanism underlying the development of insulin resistance-associated metabolic diseases. Breaking the vicious cycle between insulin resistance and trained immunity by inducing innate immune cells to establish immune tolerance and inhibiting excessive inflammatory reactions caused by various secondary metabolic disorders of insulin resistance represents a novel strategy for early prevention and treatment of related metabolic diseases. As is widely known, exercise intervention serves as an effective means to improve insulin resistance-related metabolic diseases. It promotes metabolic homeostasis by exerting anti-inflammatory effects, yet the underlying mechanism of these anti-inflammatory effects remains unclear. Numerous studies suggest that after a high-fat diet generates innate immune memory, exercise intervention may alleviate excessive inflammatory reactions caused by secondary metabolic disorders due to insulin resistance by inducing immune tolerance in innate immune cells, and promote early prevention and treatment of related metabolic diseases. Therefore, targeting innate immune cell immune tolerance to explore the anti-inflammatory mechanism of exercise intervention in insulin resistance holds exciting and vast prospects. Metabolic reprogramming refers to the process in which cells undergo systematic adjustments and transformations in their energy requirements and metabolic patterns to adapt to changes in the external environment and meet their own needs for proliferation and differentiation under specific physiological and pathological conditions. Numerous studies have shown that metabolic reprogramming plays a crucial role in tumor biology, immunology, stem cell research, and the occurrence and development of various diseases. Increasing evidence suggests that metabolic reprogramming is also a key mechanism for innate immune cells to respond to external stimuli and perform immune functions. The process of immune tolerance is also driven by metabolic reprogramming. Studying the mechanisms of innate immune cell immune tolerance from the perspective of metabolic reprogramming is expected to provide new directions for the prevention and treatment of chronic inflammation and related metabolic diseases. Meanwhile, exercise has been proven to regulate metabolic reprogramming in various cells. It may induce immune tolerance in activated innate immune cells by inhibiting glycolysis and enhancing their oxidative phosphorylation levels, thereby mitigating excessive inflammatory reactions and achieving early prevention and treatment of insulin resistance-related metabolic diseases. Itaconate, an intermediate product of the tricarboxylic acid cycle, represents a newly discovered central regulatory point for balancing the trained immunity and immunity tolerance in innate immune cells. Additionally, exercise modulates IRG1/itaconate signaling. Therefore, conducting an in-depth exploration of the interrelationships between trained immunity, immunity tolerance, metabolic reprogramming, and IRG1/itaconate signaling in exercise intervention for insulin resistance, as well as summarizing the immune tolerance mechanism of exercise in improving insulin resistance, can provide theoretical support for the preventive and therapeutic effects of exercise in insulin resistance and related metabolic diseases. This can also offer new insights for the development of simulated drugs tailored for individuals with exercise intolerance.

Abstract:Depression, also known as major depressive disorder (MDD), is an emotional disorder characterized by low mood, decreased interest, and lack of energy, which imposes a heavy burden on families and society. Neuromodulation technology has made significant progress in improving depressive symptoms by using invasive or non-invasive methods, such as electricity and magnetism, to regulate neural activity in specific areas of the brain. Determining objective evaluation indicators can provide reliable basis for the development of neural regulation strategies and efficacy evaluation in MDD. This article systematically reviews the latest application progress of non-invasive neural regulation techniques such as transcranial magnetic stimulation (TMS), transcranial electrical stimulation (TES), and transcranial ultrasound stimulation (TUS), as well as invasive neural regulation techniques such as deep brain stimulation (DBS), optogenetics, and chemical genetics in MDD. The focus is on exploring behavioral, neuroimaging, and neurophysiological evaluation indicators of neural regulation, providing direction for the development of precise and personalized neural regulation schemes and assessment tools for MDD in the future.

Abstract:Transcranial focused ultrasound (tFUS) technology achieves precise stimulation or treatment of the area of interest in the head by directing ultrasound beams to penetrate the human skull to form an intracranial focal point, with the advantages of eliminating the need for craniotomy and the absence of ionizing radiation. High-intensity tFUS treats brain diseases such as essential tremor or brain tumors through thermal effects, while low-intensity tFUS can safely and reversibly open the blood-brain barrier or conduct neuromodulation studies through mechanical effects. However, in practical applications, ultrasound waves undergo strong phase distortion and energy attenuation due to the strong acoustic attenuation properties and inhomogeneous structure of the skull. Acoustic simulation models the interaction between ultrasound and media based on acoustic fluctuation equations to predict the propagation properties of sound waves in different media. Therefore, acoustic simulation is commonly used to predict the intracranial acoustic field for single-element tFUS or to perform phase correction for each element of multi-element tFUS to ensure accurate focusing of intracranial ultrasound. According to the different methods of solving the acoustic fluctuation equations, the commonly used acoustic simulation methods in tFUS can be categorized into numerical and semi-analytical methods. The numerical methods include k-space pseudo-spectral method, time-domain finite difference method and finite element method, etc., and the semi-analytical methods include ray-tracing method and hybrid angular spectrum method. Simulation tools based on numerical methods synthesize various forms of wave propagation in media, such as nonlinear effects, scattering and diffraction, and are widely used in academic research. The k-Wave toolbox based on the k-space pseudo-spectral method and various programs based on the time-domain finite-difference method are the most widely used simulation tools in the current tFUS accurate simulation and experimental research. Although the finite element method has the advantage of dealing with complex boundary conditions, the excessive consumption of computational resources limits its direct application in complex 3D simulations. Compared to numerical methods, semi-analytical-based simulations cannot accurately model full-wave effects, but their computational speed makes them more suitable for clinical scenarios where simulation time is critical. Ray-tracing, developed by Insightec, is currently the only phase-correction method that has been used in clinical applications. Based on geometric acoustic principles, ray tracing enables near real-time tFUS phase correction. At the same time, the hybrid angular spectroscopy method shows higher accuracy in precise targeting than the conventional ray tracing method. In addition, the hybrid application of different simulation methods significantly improves the simulation efficiency and accuracy, e.g., the boundary element method can be coupled with the finite element method to limit the computational area to the region involving only the skull, which drastically reduces the computational load. In recent years, the acoustic simulation for tFUS has continued to make progress, but there is still a huge room for improvement in terms of computational efficiency and accuracy, and the optimal use of computational resources and the combination of multiple simulation techniques may be the direction of the future development of simulation technology. In this paper, the research on simulation techniques based on numerical, semi-analytical and hybrid methods commonly used in the field of tFUS in recent years is reviewed and sorted out, and the research and application of various simulation methods are summarized and prospected.

Abstract:Objective To characterize transmembrane protein 68 (TMEM68) in an alternative triacylglycerol (TAG) biosynthesis pathway, and determine the interplay between TMEM68 and the canonical TAG synthesis enzyme acyl-CoA:diacylglycerol acyltransferase (DGAT).Methods Effects of exogenous fatty acid and monoacylglycerol on TAG synthesis and lipid droplet (LD) formation in TMEM68 overexpression and knockout cells treated with DGAT inhibitor or not were investigated by comparing LD morphology, Oil Red O staining, and measurement of TAG levels. LDs were stained with fluorescence dye and observed by confocal fluorescence microscopy. TAG levels were determined with an enzyme-based triglyceride assay kit. Colocalization of TMEM68 and DGAT1 was detected by co-expression and confocal fluorescence microscopy and their interaction was determined by co-immunoprecipitation. RT-qPCR and immunoblotting assay were used to detect the expression of DGAT1.Results The synthesis of TAG catalyzed by TMEM68 was independent of DGAT activity. Surplus exogenous fatty acids and monoacylglycerol promoted TAG synthesis mainly through DGAT in human neuroblastoma cells. The LDs formed by TMEM68 were different in morphology from those by DGAT. In addition, TMEM68 and DGAT1 colocalized in the same endoplasmic reticulum (ER) compartment but did not interact physically. TMEM68 overexpression reduced the expression of DGAT1, the major DGAT enzyme involved in TAG synthesis, while TMEM68 knockout had little impact.Conclusion The TMEM68-mediated TAG synthesis pathway has distinct features from the canonical DGAT pathway, however, TMEM68 and DGAT may coregulate intracellular TAG levels.

Abstract:Objective The aim of this study was to investigate the effect and mechanism of quercetin on lipid droplet formation in foam cells induced by oxidized low-density lipoprotein (ox-LDL).Methods Mouse RAW264.7 cells were induced by 50 mg/L ox-LDL to construct a foam cell model. After different quercetin concentrations were treated for different time, the optimal quercetin concentration and time were screened by CCK8 assay. Based on the constructed foam cell model, the formation of fat droplets was observed by oil red O staining after quercetin treatment with or without AS1842856 (FOXO1 inhibitor). Apoptosis was detected by flow cytometry. The protein expression of FOXO1 in each group was detected by Western blot. Autophagosome formation was observed by acridine orange staining. The mRNA and protein expression levels of Beclin1, LC3II and P62 were detected by qRT-PCR and Western blot.Results After being treated with 100 μmol/L quercetin for 12 h, the formation of fat droplets and apoptosis of foam cells were inhibited (P<0.05). Compared with control group, there was an increase in fat droplet formation and apoptosis (P<0.05), a decrease in autophagosome (P<0.05), a decrease in FOXO1 protein expression (P<0.05), a decrease in Beclin1 and LC3II protein and mRNA expression levels (P<0.05), and the expression levels of P62 protein and mRNA were found to be increased (P<0.05) in model group. Compared with model group, quercetin treatment up-regulated FOXO1 protein expression (P<0.05), induced autophagosome formation (P<0.05), promoted the protein and mRNA expression levels of Beclin1 and LC3II (P<0.05), and inhibited the protein and mRNA expression levels of P62 (P<0.05). In addition, treatment with the FOXO1 inhibitor AS1842856 reversed quercetin’s effect on OX-LDL-induced foam cells.Conclusion Quercetin induced autophagy by upregulating FOXO1 expression and inhibited fat droplet formation induced by OX-LDL.

Abstract:Objective Stroke is a leading cause of death and disability worldwide, with ischemic stroke accounting for 80%-85% of cases. Despite the prevalence, effective treatments remain scarce. The compelling evidence suggest that high concentrations of ATP in the brain post-stroke can trigger irreversible neuronal damage and necrosis, contributing to a range of neurocellular dysfunctions. Pyroptosis, a recently identified form of programmed cell death, is characterized by caspase-1 activation and the action of the Gasdermin D (GSDMD) protein family, leading to cell perforation and inflammatory death.Methods In this study, human neuroblastoma SH-SY5Y cells were used to investigate the mechanisms of ATP-induced neurotoxicity and the protective effects of hydrogen sulfide (H₂S) against this toxicity through the antagonization of pyroptosis. We employed CCK-8 and LDH assays to assess cell viability. YO-PRO-1 fluorescent dyes and flow cytometry were conducted for detecting changes in cell membrane permeability. Western blot analysis was used to measure protein levels associated with cellular dysfunction.Results Our results indicate that high concentrations of ATP enhance cytotoxicity and increase cell membrane permeability in SH-SY5Y cells, that are mitigated by the H₂S donor NaHS. Furthermore, ATP was found to promote the activation of the NOD-like receptor pyrin domain-containing 1 (NLRP-1), caspase-1, and the cleavage of GSDMD, with NaHS significantly attenuating these effects.Conclusion Our research suggests that H₂S protects SH-SY5Y cells from ATP-induced neurotoxicity through a mechanism mediated by the NLRP1, caspase-1, and GSDMD pathway.

Abstract:Objective To investigate whether 2,3,5,4"-tetrahydroxystilbene-2-O-β-glucoside (TSG) ameliorated polycystic ovary syndrome (PCOS)-like characteristics by inhibiting inflammation.Methods PCOS models were established by injecting subcutaneously with dehydroepiandrosterone into female Sprague-Dawley rats, followed by receiving intraperitoneal injection of TSG. The granular cells (GCs) KGN were transfected with small interfering RNAs (si-NC and si-CYP19A1). The cells were preincubated with lipopolysaccharide (LPS) and then treated with or without TSG. The estrous cycle was monitored using vaginal exfoliated cells. The morphology of ovarian follicles was analyzed by H&E staining. ELISA was used to analyze estradiol (E2), testosterone (T), follicle stimulating hormone (FSH), luteinizing hormone (LH), IL-6, TNF-α, AGEs, CRP and Omentin-1 levels in serum. Immunohistochemistry was performed to analyze PCNA and CYP19A1 expressions in the GCs of ovaries. Tunel staining was executed to detect the apoptosis of GCs. Quantitative polymerase chain reaction (qPCR) and Western blot were implemented to measure the expression of CYP19A1 in the ovaries and transfected cells. qPCR was used to analyze the expression of IL-6 and TNF-α in the transfected cells treated with LPS and TSG.Results The estrous cycles were restored in TSG group. Compared with model group, the sinus follicles were reduced and corpus luteums were increased in TSG group. TSG group showed increased E2, and decreased T and LH, compared with model group. Pro-inflammatory factors (IL-6, TNF-α, CRP and AGEs) were decreased, and anti-inflammatory factor (Omentin-1) was increased in TSG group compared with those in model group. TSG could partially inhibit decrease of PNCA-positive GCs and increase of Tunel-positive GCs caused by PCOS. The CYP19A1 expression of GCs in TSG group was upregulated compared with model group. The expressions of IL-6 and TNF-α in si-CYP19A1 cells were increased compared with si-NC cells. Compared with cells (si-NC and si-CYP19A1) treated without LPS, the expressions of IL-6 and TNF-α cells were increased, and the expression of CYP19A1 was downregulated in LPS-preincubated cells. Compared with cells treated with LPS, the expression of IL-6 and TNF-α were decreased, and the expression of CYP19A1 was increased in cells treated with LPS and TSG. Compared with si-NC cells treated with LPS and TSG, the expressions of IL-6 and TNF-α cells were increased in the si-CYP19A1 cells treated with LPS and TSG.Conclusion TSG could alleviate PCOS-like characteristics by increasing the expression of CYP19A1 in GCs to inhibit inflammatory response.

Abstract:Objective To explore the mechanism of exercise intervention in improving autism-like behaviors in Shank3 gene knockout (Shank3^-/-) induced autism spectrum disorder (ASD) rat models from an autophagy perspective through 8-week swimming intervention.Methods Based on genotype identification and exercise intervention, rats were divided into four groups (n=15): wild-type control group (WC), Shank3^-/- control group (KC), wild-type swimming group (WS), and Shank3^-/- swimming group (KS). KS and WS groups underwent 8 weeks of swimming exercise, 5 d/week, gradually increasing to and maintaining 40 min/session. Behavioral experiments, including self-grooming test, marble burying test, and hole-board test, were conducted 24 h after the final swimming intervention. Tissue sampling was performed 12 h after behavioral testing. Transmission electron microscopy was used to observe autophagosome numbers in the striatum region. Immunofluorescence staining was employed to observe the expression levels of microtubule-associated protein 1 light chain 3 (LC3) and selective autophagy adaptor protein (p62). Quantitative real-time polymerase chain reaction (qPCR) and Western blot were used to detect protein and mRNA expression of Beclin1, LC3, p62, autophagy-related protein 5 (Atg5), autophagy-related 16-like protein 1 (Atg16L), and lysosome-associated membrane protein 1 (LAMP1) in striatal.Results Compared with the WC group, rats in the KC group exhibited significantly higher self-grooming frequency and duration (P0.05), increased marble burying behavior (P0.01), and elevated frequencies in both hole-board exploration and single-hole exploration (P0.05). Following 8 weeks of swimming intervention, the KS group demonstrated significantly reduced self-grooming duration, marble burying behavior, and single-hole exploration frequency compared to the KC group. Furthermore, compared to the WC group, the KC group displayed abundant autophagosomes in the striatum region, along with significantly elevated protein and mRNA expression levels of Atg5, Atg16L, p62, and LC3II/LC3I ratio (P0.05), increased Beclin1 protein levels (P0.05), and markedly decreased LAMP1 protein and mRNA expression levels (P0.05). Following the 8-week swimming intervention, the KS group exhibited significantly reduced protein and mRNA expression levels of Atg5, Atg16L, p62, and LC3II/LC3I ratio (P0.05), decreased Beclin1 protein levels (P0.05), and significantly elevated LAMP1 protein and mRNA expression levels (P0.05) compared to the KC group.Conclusion Early 8-week swimming can alleviate stereotyped behaviors in Shank3^-/- rats by regulating striatal cell autophagy.

Abstract:Objective Electroencephalography (EEG) serves as a non-invasive electrophysiological monitoring technique employed to record brain electrical activity. Nonetheless, traditional EEG electrodes are susceptible to reference activation influences and exhibit limited spatial resolution. Laplacian electrodes, devoid of reference dependencies, possess the potential to amplify the spatial resolution of EEG recordings. Anchored in the utilization of bipolar concentric ring Laplacian electrodes, this study delves into the autonomous referencing attributes intrinsic to Laplacian electrodes. Furthermore, it conducts a comparison of spatial resolution disparities between Laplacian electrodes and their conventional counterparts.Methods A three-dimensional (3D) hemispherical tank experiment was conducted utilizing 21 Ag/AgCl bipolar concentric ring Laplacian electrodes to simulate whole-brain signal acquisitions. A sinusoidal signal with an amplitude of 400 mVpp@13 Hz was employed for detection. The positions of the ground electrodes in the Laplacian electrode array were varied, alongside the reference electrode positions in the case of the traditional electrodes. Subsequently, the spatial distribution of the 13 Hz source frequency component was extracted and subjected to comprehensive analysis.Results With varying ground electrode positions, the spatial distribution of the signal-to-noise ratio (SNR) among Laplacian electrodes maintains remarkable consistency, yielding a correlation coefficient of 0.94. In contrast, for traditional electrodes, the correlation coefficient for SNR distribution under distinct reference electrode positions barely reaches 0.07. While Laplacian electrodes exhibit independence from reference electrodes, traditional counterparts display a notable susceptibility to changes in reference electrode positions. Comparing amplitude’s 3 dB attenuation area ratio, Laplacian electrodes showcase a mere 2.1% reduction, a significantly favorable outcome when juxtaposed with the 6.9% reduction evident in traditional electrodes. Similarly, the SNR’s 3 dB attenuation area ratio for Laplacian electrodes is a mere 1.0%, contrasting with the considerably higher figure of 30.1% for traditional electrodes.Conclusion Laplacian electrodes remain impervious to reference electrode influence, displaying distinctive reference-independent attributes, in addition to boasting a heightened spatial resolution. These characteristics imbue them with the capacity to achieve heightened precision in localizing brain electrical activities, thus constituting a cornerstone for the integration of Laplacian electrodes into brain-computer interfaces (BCIs).

Abstract:Objective Cancer is a global public health issue that has attracted much attention. Detecting and treating cancer at an earlier time point is the key to improving cancer survival rates. However, due to factors such as high equipment cost, slow detection speed, and poor detection accuracy, the promotion of early cancer screening is limited. Therefore, this paper proposes a high-precision and high-speed bioimpedance spectroscopy detection method for tumor identification based on multi-frequency synchronous bioimpedance spectroscopy technology.Methods First, based on the multi-frequency synchronization technology, this paper built a multi-frequency synchronous bioimpedance spectrum detection system, realized the high-speed detection of bioimpedance spectrum, designed concentric circle sensors to reduce the influence of biological tissue anisotropy on impedance detection, and improved the discrimination of bioimpedance spectrum between different tissues. Secondly, a gastric wall tissue model was established, and the degree of anisotropy influence on traditional four-electrode sensors and concentric circle sensors was studied through simulation. Finally, through pork tissue detection experiments and clinical gastric cancer tissue detection experiments, it was verified that the multi-frequency synchronous bioimpedance spectroscopy detection system using concentric circle sensors has higher detection accuracy.Results The experimental results show that when using concentric circle sensors, the average overlap rate of detection results is 13.4%, which is 41.7% lower than that of traditional electrodes, and the average discrete coefficient (C_v) is 7.6%, which is 54.0% lower than that of traditional electrodes. The multi-frequency synchronous bioimpedance spectrum detection system takes about 20 ms to perform a detection, and the detection method proposed in this paper has higher detection accuracy and detection speed. Finally, the concentric circle electrodes were selected to conduct clinical experiments on human gastric cancer tissue, and normal tissue and tumor tissue were successfully distinguished.Conclusion The high-precision and high-speed bioimpedance spectroscopy detection method for tumor identification proposed in this paper can effectively reduce the influence of anisotropy of biological tissues and obtain higher-precision and higher-speed detection results.

Abstract:Objective Molecular property prediction plays a crucial role in drug development, especially in virtual screening and compound optimization. The advancement of artificial intelligence (AI) technologies has led to the emergence of numerous deep learning-based methods, which have demonstrated significant potential in improving molecular property prediction. Nonetheless, acquiring labeled molecular data can be both costly and time-consuming. The scarcity of labeled data poses a substantial challenge for supervised machine learning models to effectively generalize across the vast chemical space. In order to overcome the above limitations, in this work, we proposed a novel Bert and GCN-based multimodal fusion method (called BGMF) to predict molecular property.Methods BGMF can extract comprehensive molecular representation from atomic sequences, molecular fingerprint sequences, and molecular graph data and combine them through pre-training and fine-tuning. Specifically, our method consists of the following three main parts. (1) Molecular feature extraction; (2) Bert-GCN based pre-training; (3) fine-tuning. During molecular feature extraction, the Morgan algorithm is employed to generate the molecular fingerprints, transforming input SMILES strings of drugs into molecular fingerprint sentences. Simultaneously, atom sentences are created based on the atom indices within the molecule, Consequently, drug molecule are represented as both molecular fingerprint sentences and atom sentences. In the pre-training section, BGMF utilizes a self-supervised learning strategy, specifically masked molecular fingerprint and masked atom recovery, on a large dataset of unlabeled data using the Bert model. Here, molecular graph data is incorporated by merging graph convolutional neural networks with the Bert model, effectively combining the global “word” features of drug molecules with the local topological features of molecular graphs. We have also developed a dual decoder for atomic and molecular fingerprints to amplify molecular feature expression. Finally, in the fine-tuning stage, the addition of a pooling layer and task-specific fully connected neural networks allows the pre-trained module to be applied to a variety of downstream tasks for molecular property prediction.Results To validate the effectiveness of our BGMF, we conduct several experiments on 43 molecular attribute prediction tasks across 5 datasets. In comparison with other recent state-of-the-art methods, our BGMF achieves the best results in terms of area under the ROC curve (AUC). We also verified the generalization performance of the BGMF model by constructing independent test dataset, showing that the BGMF model has the best generalization performance. Additionally, we conduct the ablation studies to demonstrate the effect of atomic sequence, molecular fingerprint sequence, GCN based molecular graph module, and pre-training module on the overall performance of the model.Conclusion In this paper, we propose a novel method for drug molecular attribute prediction named BGMF which integrating the molecular graph data into tasks of molecular fingerprint recovery and masked atom recovery by combining graph convolutional neural network with the Bert model. The molecular fingerprint representations generated by BGMF were visualized using t-SNE, revealing that the BGMF model effectively captures the intrinsic structure and features of molecular fingerprints.