Abstract:In recent years, nucleic acid therapy, as a revolutionary therapeutic tool, has shown great potential in the treatment of genetic diseases, infectious diseases and cancer. Lipid nanoparticles (LNPs) are currently the most advanced mRNA delivery carriers, and their emergence is an important reason for the rapid approval and use of COVID-19 mRNA vaccines and the development of mRNA therapy. Currently, mRNA therapeutics using LNP as a carrier have been widely used in protein replacement therapy, vaccines and gene editing. Conventional LNP is composed of four components: ionizable lipids, phospholipids, cholesterol, and polyethylene glycol (PEG) lipids, which can effectively load mRNA to improve the stability of mRNA and promote the delivery of mRNA to the cytoplasm. However, in the face of the complexity and diversity of clinical diseases, the structure, properties and functions of existing LNPs are too homogeneous, and the lack of targeted delivery capability may result in the risk of off-targeting. LNPs are flexibly designed and structurally stable vectors, and the adjustment of the types or proportions of their components can give them additional functions without affecting the ability of LNPs to deliver mRNAs. For example, by replacing and optimizing the basic components of LNP, introducing a fifth component, and modifying its surface, LNP can be made to have more precise targeting ability to reduce the side effects caused by treatment, or be given additional functions to synergistically enhance the efficacy of mRNA therapy to respond to the clinical demand for nucleic acid therapy. It is also possible to further improve the efficiency of LNP delivery of mRNA through machine learning-assisted LNP iteration. This review can provide a reference method for the rational design of engineered lipid nanoparticles delivering mRNA to treat diseases.

Abstract:Tumor immune microenvironment is an important microecology for tumor development, where tumor-associated macrophages are the most abundant immune cells in the tumor immune microenvironment, with high plasticity and heterogeneity. Under the regulation of various environmental factors, tumor-associated macrophages can differentiate into different subgroups. Though complex and variable, all these environmental factors ultimately regulate tumor-associated macrophages by influencing the temporal and spatial heterogeneity of these cells" internal components, structure, and functions. Mitochondrion are important organelles, responsible for energy production, metabolism, and centers of multiple signal transduction. More and more studies have found that mitochondria can regulate cell functions through various mechanisms such as morphological change, metabolic reprogramming, intermediate metabolites or mitochondrial genetic material. Mitochondrial disorders are involved in many diseases and pathological processes. Here, we review the mechanisms by which mitochondria regulate the polarization of macrophages and thus reshape the tumor immune microenvironment. Further, we discuss and prospect the current status of macrophage mitochondria-related tumor immunotherapy.

Abstract:Glycolysis is a fundamental topic in the biochemistry curriculum, pivotal for understanding glucose metabolism, and it stands as a challenging subject in various life science disciplines, including microbiology, marine biology, zoology, cell biology, and bioengineering. The process of glycolysis encompasses 10 successive reactions, involving numerous enzymes and intermediate metabolites, making it a complex pathway that both consumes and generates energy (ATP). Over the past decades, and continuing to the present, the standard pedagogical approach has been to explain glycolysis step by step, a method known as the sequential teaching method, which has not yielded optimal educational outcomes. In this paper, we introduce an innovative teaching strategy that frames the overall reaction of glycolysis as the division of one molecule of (6C) glucose into two molecules of (3C) pyruvate. To achieve the equal division of the hexose molecule, a phosphate group is added to both the head (C1) and tail (C6) of the hexose carbon chain, resulting in the formation of fructose 1,6-bisphosphate. A critical chemical bond breakage at the center of the molecule (C3-C4) then occurs, yielding two molecules of phosphorylated aldose. The subsequent five reactions involve a series of steps, including the transfer of phosphate groups, culminating in the production of pyruvate from phosphorylated aldose. This novel education approach, which begins with the concept of "equal division of the hexose carbon chain", is termed the "hexose equal division" teaching method. Graduate (n=63) and undergraduate (n=39) students were enrolled in a teaching research study where glycolysis was taught using the "hexose equal division" method, followed by a questionnaire survey. The results showed that before receiving the "hexose equal division" teaching, students found it challenging to grasp and retain the steps of glycolysis, with the reactions being prone to be forgotten after memorization. However, after employing the "hexose equal division" teaching method, the majority of graduate students reported that glycolysis steps became more comprehensible and easier to recall compared to the "sequential teaching method" used during their undergraduate studies. This same approach was applied to undergraduate students, and a statistical analysis revealed no significant difference (P>0.05) in outcome between the two groups. Consequently, the "hexose equal division" teaching method has been shown to enhance students" understanding of the glycolysis mechanism, aid in memorization, and encourage independent thinking, thus leading to improved learning outcomes.

Abstract:Alzheimer’s disease (AD), characterized by cognitive decline and neurodegeneration, currently relies on pharmacological treatments that are limited in efficacy and often accompanied by side effects. As the number of AD patients increases, so does the economic burden on both the global healthcare system and families of patients, further worsening the quality of life for patients in their later years. Therefore, it is crucial to find new and more effective therapeutic approaches. This necessity has sparked a growing interest in non-invasive therapies, such as 40 Hz rhythmic stimulation, which aims to modulate brain activity to potentially reverse pathological changes and alleviate symptoms. This review provides an overview of the effects of 40 Hz stimulation on AD pathology and symptoms, its impact on cognitive functions in healthy individuals, the underlying mechanisms of action, and strategies to enhance the treatment"s compliance and effectiveness. Research has demonstrated that 40 Hz rhythmic stimulation, particularly through auditory and visual modalities, can influence core AD pathologies. In mouse models of AD, this stimulation has been shown to reduce amyloid-beta protein (Aβ) plaques and phosphorylated tau protein levels, hallmarks of AD pathology. These effects are thought to stem from enhanced waste clearance mechanisms, facilitated by the stimulation of the glymphatic system and the activation of microglia. Clinical applications in AD patients have shown promising results, with improvements noted in cognitive functions and behavioral symptoms. These findings suggest that 40 Hz rhythmic stimulation could offer a non-pharmacological option to mitigate the pathological progression and symptomatic expression of AD. In healthy individuals, the cognitive outcomes of 40 Hz stimulation appear more variable. Some studies indicate potential enhancements in memory and attention, proposing that 40 Hz stimulation may bolster cognitive resilience and processing efficiency in a non-diseased brain. However, these effects are not consistently replicated across studies, indicating that individual differences and specific stimulation parameters may significantly influence outcomes. The beneficial effects of 40 Hz rhythmic stimulation are believed to be primarily due to neural entrainment, where neural circuits synchronize their activity to the external frequency. This entrainment may restore the balance between excitatory and inhibitory neural activity, which is often disrupted in AD mice and AD patients. By reinforcing natural brain rhythms, 40 Hz stimulation may enhance neural connectivity and function, facilitating cognitive and memory processes that are deteriorated in AD. Neural entrainment at 40 Hz has been demonstrated to aid in restoring neural network function, enhancing the glymphatic system, improving cerebral blood flow, and providing neuroprotection. These mechanisms are thought to work synergistically to regulate brain activity, potentially leading to a reduction in lesions and an improvement in cognitive performance. To optimize the therapeutic benefits of 40 Hz stimulation, several factors need to be considered. Treatment protocols should be tailored to individual needs, accounting for variability in disease progression and personal health status. Enhancing patient compliance involves simplifying treatment regimens and using portable, user-friendly devices that can be easily incorporated into daily routines. Ongoing research should focus on refining stimulation parameters and delivery methods to maximize efficacy and minimize potential side effects. In conclusion, while 40 Hz rhythmic stimulation represents a promising avenue for treating AD and enhancing cognitive functions, further research is required to fully elucidate its mechanisms, refine its application, and ensure its practicality and efficacy in broad clinical and everyday settings.

Abstract:In recent years, with the continuous development of in situ cryo-electron microscopy (cryo-EM) and artificial intelligence (AI) technologies, the research of structural biology has undergone a paradigm shift. Structural analysis is no longer confined to isolated and purified biomolecules, and determination of high-resolution in situ structures directly within cells and tissues becomes feasible. Furthermore, structural analysis of the molecular landscapes of subcellular regions can be performed to gain a deeper understanding of the molecular mechanisms of living activities in the native functional context. Through determining in situ structures of various protein complexes within the cell, it is feasible to visualize the proteome with spatial and quantitative information, which is often referred to as visual proteomics. Emerging in situ structural methods represented by cryo-electron tomography (cryo-ET) hold the promise to elucidate the three-dimensional interaction networks of the intracellular proteome and understand their activities in a systematic manner. To advance in situ cryo-EM/ET and visual proteomics in China, this review summarizes the new research paradigms and technological advances, showcases the superiority of new concepts and technologies with representative examples, and discusses the future prospects in the field.

Abstract:Cancer stem cells (CSCs), a small subset of cells in the tumor bulk with the ability of self-renewal and differentiation, are the key to tumor occurrence, metastasis, drug resistance and relapse. CSCs are resided in a specific microenvironment, and their number maintenance, self-renewal and differentiation are precisely regulated by the microenvironment, and the immune microenvironment is one of the most critical microenvironments for CSCs. In recent years, tumor immunotherapy has achieved great success, but drug resistance and recurrence are frequently occurred after immunotherapy. Compared with non-CSC tumor cells, CSCs harbor stronger immune escape ability, and their roles in tumor immune escape are increasingly followed. In this review, we described the discovery history and lineage sources of CSCs, focused on immune cells in the CSC microenvironment, such as tumor-infiltrating lymphocytes, tumor-associated macrophages, and tumor-associated dendritic cells, and analyzed the mechanism of "CSC-immune cell" interaction. Intervention strategies targeting CSCs and their immune microenvironment are also described. With the development and application of advanced technologies such as "CSC-immune cell" co-culture, single-cell sequencing and lineage tracing, the immune escape of CSCs can be suppressed by targeting the interaction between CSCs and immune cells or reversing the immunosuppressive microenvironment, which is expected to provide potential solutions to the problems of drug resistance and relapse in tumor immunotherapy.

Abstract:With changes in human lifestyle, chronic diseases caused by metabolic disorders, such as obesity, type 2 diabetes, and non-alcoholic fatty liver disease, have become serious public health issues threatening human health. These diseases not only significantly increase the disease burden on humans but also put immense pressure on global healthcare systems. Therefore, understanding and exploring the molecular mechanisms leading to these diseases, especially the role of metabolic regulators, is crucial for developing effective prevention and treatment strategies. KLF15, one of the highly conserved members of the KLF family, has gained widespread attention due to its expression and regulatory roles in various metabolically active organs. Recent studies have shown that KLF15 regulates glucose, lipid, and amino acid metabolism in adipose tissue, skeletal muscle, and liver, and is closely related to the acquisition, transport, and utilization of nutrients. The role of KLF15 in glucose metabolism is primarily reflected in its regulation of gluconeogenesis and glucose uptake. KLF15 influences blood glucose levels by regulating the expression of key gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PEPCK). Research has shown that KLF15 knockout (KO) mice exhibit severe hypoglycemia and reduced liver glycogen content after 18 h of fasting. Additionally, KLF15 interacts with muscle enhancer factor 2 (MEF2A) to activate the GLUT4 promoter, significantly enhancing glucose uptake in skeletal muscle and adipose tissue. In insulin-resistant individuals, KLF15 expression is reduced, affecting insulin sensitivity by regulating genes related to lipid metabolism and mitochondrial function. In terms of lipid metabolism, KLF15 expression significantly increases during adipocyte differentiation, regulating the expression of genes such as C/EBPβ, C/EBPδ, and PPARγ. KLF15 KO mice show reduced lipogenesis and increased lipolysis, highlighting its importance in fat storage and energy balance. In brown adipose tissue (BAT), KLF15 regulates genes involved in lipid uptake and thermogenesis, such as CD36, Slc25a20, and Cpt1a. KLF15 KO mice fail to maintain body temperature during fasting-induced cold exposure, demonstrating the critical role of KLF15 in BAT metabolism and energy balance. Specifically, KLF15 forms positive feedback loops with adipogenic transcription factors such as glucocorticoid receptor (GR), PPARγ, and C/EBP, promoting adipocyte differentiation and maturation. In BAT, KLF15 is crucial not only for regulating lipid uptake but also for promoting non-shivering thermogenesis by regulating thermogenic genes, thereby helping to maintain body temperature in cold environments. In protein metabolism, KLF15 regulates key enzymes involved in branched chain amino acid (BCAA) metabolism, such as BCAT2 and ALT, which are essential for gluconeogenesis and maintaining blood glucose levels. KLF15 KO mice show reduced expression of these enzymes, leading to impaired amino acid catabolism. KLF15 regulates muscle protein synthesis and degradation through the mTOR pathway and E3 ubiquitin ligases (e.g., Atrogin-1 and MuRF1), indicating its significance in muscle protein metabolism and stress response, especially in glucocorticoid-induced muscle atrophy. Studies have shown that KLF15 expression in muscle tissue is regulated by GR. Glucocorticoids regulate KLF15 expression through GR, which in turn affects the mTOR signaling pathway, inhibiting protein synthesis and promoting protein degradation. This mechanism is particularly significant in glucocorticoid-induced muscle atrophy. KLF15 also responds significantly to exercise, particularly acute endurance exercise and long-term aerobic training. Acute endurance exercise increases KLF15 expression in muscle and adipose tissue, enhancing lipid synthesis and protein catabolism. In contrast, chronic exercise reduces KLF15 expression, improving insulin sensitivity and mitigating diabetes-induced myopathy. However, further research is needed to explore the effects of different forms of exercise on KLF15 and its specific roles in various tissues. In conclusion, KLF15 plays a crucial role in maintaining overall metabolic balance. It regulates glucose, lipid, amino acid, and protein metabolism, responding to nutritional status and exercise to maintain energy homeostasis. The role of KLF15 in glucose metabolism involves regulating gluconeogenesis and glucose uptake, in lipid metabolism through regulating fat synthesis and breakdown, and in protein metabolism through influencing branched-chain amino acid metabolism and muscle protein synthesis and degradation. Future research should continue to delve into the specific mechanisms of KLF15 in different metabolic pathways, especially its regulatory roles under various exercise forms and nutritional states, to provide new perspectives and theoretical foundations for treating metabolic diseases.

Abstract:Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant solid tumor of the digestive system, characterized by rapid progression and difficulties of early diagnosis. Five-year survival rate of the patients is less than 9%. With the acceleration of global population aging and lifestyle change, the incidence of PDAC has been increasing annually. Currently, surgical treatment and chemotherapy remain the standard treatment options for PDAC patients. Early symptoms of PDAC are so undetectable that most patients miss the optimal opportunity for radical surgical resection. Even among those who undergo surgery, the high recurrence rate remains a major problem. PDAC is known for its unique tumor microenvironment. The cellular and non-cellular components in the tumor microenvironment account for as much as 90% of the tumor stroma, presenting many potential targets for PDAC therapy. Activated pancreatic stellate cells within PDAC tissue express specific proteins and secrete various cytokines and metabolites, which directly contribute to the proliferation, invasion, and metastasis of PDAC cells. These elements are critical in extracellular matrix production, connective tissue hyperplasia, immune tolerance, and drug resistance. Immune cells, such as macrophages and neutrophils, exert immunosuppressive and tumor-promoting roles in PDAC progression. The extracellular matrix, which serve as a natural physical barrier, induces interstitial hypertension and reduces blood supply, thereby hindering the delivery of drugs to the tumor. Additionally, it helps the metastasis and differentiation of PDAC cells, reducing the efficacy of clinical chemotherapy and immunotherapy. Although chemotherapeutic agents like gemcitabine have been used in the clinical treatment of PDAC for more than 20 years, the curative effect is obstructed by their poor stability in the bloodstream, low cellular uptake, and poor targeting. While small-molecule inhibitors targeting mutations such as KRAS^G12C, BRCA, and NTRK fusion have shown great potential for molecular targeted treatments and gene therapies of PDAC, their broader application is limited by side effects and restricted scope of patients. The advancement of nanotechnology brings new strategies for PDAC treatment. By virtue of unique size characteristics and actual versatility, different drug-delivery nanosystems contribute to overcome the dense stromal barrier, prolong the circulation time of therapeutics and realize precise PDAC treatment by targeted drug delivery. Clinical nanodrugs such as albumin-bound paclitaxel (nab-paclitaxel) and irinotecan liposome greatly improve the pharmacokinetics of conventional chemotherapeutics and promote drug accumulation inside the tumor, thereby are applying to the first-line treatment of PDAC. It is noteworthy that none nanodrugs with active targeting design have been approved for clinical treatment yet, though many are in clinical trials. In this review, we discuss promising targeting strategies based on different nanodrug delivery systems for treatment of PDAC. One major nanostategy focuses on the tumor cell targeting and its applications in chemotherapy, molecular targeting therapy, gene therapy, and immunotherapy of PDAC. Another nanostrategy targets the tumor microenvironment, which highlights the nanosystems specifically regulating pancreatic stellate cells, immune cells and the extracellular matrix. Recent progress of developing new nanotheraputics for breakthrough in the fight of PDAC are elaborated in this review. We also provide our perspectives on the challenges and opportunities in the field.

Abstract:The mutations in human disease-causing genes are predominantly caused by point mutations, with more than half of them being transitions between guanine (G) and adenine (A). Precise and efficient in situ repair of these mutations is the most ideal approach for the treatment of genetic diseases. Given that most point mutations are transitions between guanine and adenine, adenine base editors (ABEs) based on the CRISPR/Cas9 system, which convert A to G, are particularly important for repairing these mutations in the treatment of human genetic diseases. In recent years, adenine base editors have been continuously optimized, with both activity and fidelity being improved. Here we summarize the progress of adenine base editors, especially these key mutants developed during the process of adenine base editor optimization. It also reflects on the existing defects in current adenine base editors. Additionally, the article reviews the clinical applications (including preclinical studies) of ABE. Overall, the article aims to provide references for the discovery and optimization of new adenine base editors and their applications.

Abstract:Collagen is a major structural protein in the matrix of animal cells and the most widely distributed and abundant functional protein in mammals. Collagen"s good biocompatibility, biodegradability and biological activity make it a very valuable biomaterial. According to the source of collagen, it can be broadly categorized into two types: one is animal collagen; the other is recombinant collagen. Animal collagen is mainly extracted and purified from animal connective tissues by chemical methods, such as acid, alkali and enzyme methods, etc. Recombinant collagen refers to collagen produced by gene splicing technology, where the amino acid sequence is first designed and improved according to one"s own needs, and the gene sequence of improved recombinant collagen is highly consistent with that of human beings, and then the designed gene sequence is cloned into the appropriate vector, and then transferred to the appropriate expression vector. The designed gene sequence is cloned into a suitable vector, and then transferred to a suitable expression system for full expression, and finally the target protein is obtained by extraction and purification technology. Recombinant collagen has excellent histocompatibility and water solubility, can be directly absorbed by the human body and participate in the construction of collagen, remodeling of the extracellular matrix, cell growth, wound healing and site filling, etc., which has demonstrated significant effects, and has become the focus of the development of modern biomedical materials. This paper firstly elaborates the structure, type, and tissue distribution of human collagen, as well as the associated genetic diseases of different types of collagen, then introduces the specific process of producing animal source collagen and recombinant collagen, explains the advantages of recombinant collagen production method, and then introduces the various systems of expressing recombinant collagen, as well as their advantages and disadvantages, and finally briefly introduces the application of animal collagen, focusing on the use of animal collagen in the development of biopharmaceutical materials. Applications, focusing on the use of animal disease models to explore the effects of recombinant collagen in wound hemostasis, wound repair, corneal therapy, female pelvic floor dysfunction (FPFD), vaginal atrophy (VA) and vaginal dryness, thin endometrium (TE), chronic endometritis (CE), in vivo regeneration of bone tissue, cardiovascular disease, breast cancer (BC), and anti-ageing, and there are studies proving that the effects of mechanism of action of recombinant collagen in the treatment of FPFD and CE, and also elaborated the clinical therapeutic effects of recombinant collagen in skin burns, skin wounds, dermatitis, acne, and genitourinary syndromes of menopause (GSM). From the exploratory studies and clinical applications, it is evident that recombinant collagen has demonstrated surprising effects in the treatment of all types of diseases, such as reducing inflammation, promoting cell proliferation, migration and adhesion, increasing collagen deposition, and remodeling the extracellular matrix. At the end of the review, the challenges facing recombinant collagen are summarized: to develop new recombinant collagen types and dosage forms; to explore the mechanism of action of recombinant collagen, and to provide an outlook for the future development and application of recombinant collagen.