Abstract:Extracellular polysaccharides serve as the major structural components of Pseudomonas biofilm matrix, which can enhance the tolerance of bacteria for environment, antimicrobials and host defense. Pseudomonas mainly produce three key extracellular polysaccharides implicated in biofilm formation: alginate, Psl and Pel, and their synthesis and transport depend on the corresponding alginate, Psl and Pel biosynthetic systems. Therefore, this review comprehensively summarizes the progress on structural biology of Pseudomonas biofilm formation-related three exopolysaccharide biosynthetic systems, and describes the known structures and functions of proteins in these three systems. On this basis, new insights are put forward for future research directions, which can lay a solid theoretical foundation for formation mechanism and control strategies of Pseudomonas biofilm.

Abstract:Cardiovascular and cerebrovascular diseases caused by atherosclerosis (AS) are a kind of diseases that seriously damage human health. In recent years, it has been found that trimethylamine oxide (TMAO), a metabolite of intestinal flora, plays an important role in the pathogenesis of AS: inhibition of cholesterol reverse transport, up regulation of scavenger receptor expression, promotion of foam cell formation, reduction of bile acid pools, enhancement of platelet reactivity, increase of thrombosis risk, damage of vascular endothelium and promotion of inflammatory response. More and more scholars have paid attention to the specific effect and exact mechanism of TMAO on AS. This paper reviews the general characteristics of TMAO, the role of TMAO in the development of AS, and the latest research progress in the prevention and treatment of AS by intervening with TMAO.

Abstract:The balance of intracellular cholesterol level is important for the physiological function of cells. Disrupted the dynamic balance of intracellular cholesterol level not only significantly increases the risk of cardiovascular diseases, but also is associated with many metabolic diseases. Intracellular cholesterol level is mainly regulated by cholesterol biosynthesis, uptake, efflux and esterification. 3-Hydroxy-3-methyl-glutaryl coenzyme A reductase (HMGCR), squalene monooxygenase (SQLE) and sterol regulatory element binding protein 2 (SREBP2) are key factors in cholesterol synthesis. Niemann-Pick type C1-like 1 (NPC1L1), low density lipoprotein receptor (LDLR) and scavenger receptor class B1 (SR-B1) are important receptors for cholesterol uptake. ATP binding cassette transporter (ABC) ABCA1, ABCG1, ABCG5/8 and apolipoprotein A-1 binding protein (AIBP) mediate intracellular cholesterol efflux. Acyl coenzyme A∶cholesterol acyltransferase (ACAT) can esterify intracellular free cholesterol. This article mainly reviews the latest research progress of the key factors that play an important role in the regulation of intracellular cholesterol level, in order to provide new targets and research directions for the regulation of intracellular cholesterol level.

Abstract:The cell mechanical properties are closely related to the physiological states and functions of cells. Early studies on the cell mechanical properties could only provide the elasticity or shear modulus of the whole cell population, which results in the loss of the mechanical phenotypes of the heterogeneous cells. In recent years, new methods for the detection of single-cell mechanical properties have been widely reported. The conventional technologies of atomic force microscopy, micropipette aspiration technology, optical tweezers and stretching, magnetic twisting cytometry and magnetic tweezers exhibit a very high detection accuracy, but have a relatively low detection throughput. The new emergence of microfluidic high-throughput detection methods could provide the possible solution for increasing the throughput. This article firstly reviews typical single-cell mechanical property detection techniques such as atomic force microscopy, micropipettes, optical tweezers and optical stretching, magnetic twisting cytometry and magnetic tweezers. Next, the working principles and the recent progresses of the newly emerging microfluidic high-throughput detection technologies, including micro-constrictions, shear-induced and stretch-induced cell deformation, are introduced. Then, the advantages and disadvantages of each method are discussed. Finally, the prospects for future development in the detection of single cell mechanical properties are also discussed.

Abstract:Slit-Robo regulates many physiologic processes, such as neuronal development, angiogenesis, organ development, cell proliferation, tumor and inflammatory response, and different downstream signal pathways can produce different physiological functions. Moreover, the interaction between Slit and Robo is not one-to-one, many Slit receptors other than Robo have been found, and Robo can also interact with ligands other than Slit. These interactions play a key role in the regulation of cell movement. This article reviews the current research progress of Slit-Robo signal transduction pathways, including the protein structure, proteolytic processing and physiological processes in vivo such as neural development, angiogenesis, organ development, cell proliferation, tumor and inflammatory response. However, the physiological processes of Slit-Robo are highly diverse, and how these differences are regulated remains unknown. We thus expect more basic and translational research.

Abstract:Kelch-like ECH associated protein 1(Keap1), a typical substrate-recognition subunit of the Cul-RING E3 ligase, plays a significant role in ubiquitination. Ubiquitination, an important post-translational modification, enables a degradation signal in both autophagy and ubiquitin-proteasome system. Recently, several substrates can be recognized and binded by wild-type Keap1, and subsequently degraded by ubiquitin proteasome system (UPS) via Keap1-Cul3-Rbx1 complex. Additionally, Keap1 has also been widely studied as a tumor suppressor protein, and mutation or abnormally deletion of Keap1 alleles contributes to different kinds of diseases. The study of Keap1 has mainly concentrated on the Keap1-Nrf2 axis, but rarely extends to downstream substrates. Given that the great importance of Keap1 in cells, this review summarizes the current research status of Keap1, including ubiquitin-proteasome system, Keap1’s structure and function, the mutation of Keap1, the substrates of Keap1, and Keap1-related diseases. It may provide a new thought for targeted therapy of Keap1-associated diseases through discussing the challenges of Keap1-related fields in clinic.

Abstract:Exosome is one of the extracellular vesicles, which plays an important role in intercellular communication and material transportation. Its content includes proteins, lipids, RNAs and other substances from host cells, and has an important influence on the physiological state of recipient cells. Flaviviridae including hepatitis C virus and Coronaviridae including SARS-CoV-2 are pathogens causing a variety of human infectious diseases. Understanding the interaction between virus and host is of great significance for screening therapeutic cellular targets and developing exosome-based vaccines. Accumulating studies have shown that exosomal protein and RNA play inhibitory roles for viruses. Moreover, Flaviviridae and Coronaviridae could hijack exosome-mediated cellular communication to harm the hosts and promote virus spread. In current review, we summarized the recent progress on the interaction between Flaviviridae/Coronaviridae and exosome, shedding the mechanistic insights into Flaviviridae/Coronaviridae induced exosome.

Abstract:DNA damage repair (SOS response) plays an important role for bacteria to adapt to the environment, resist external pressure and repair DNA damage. In order to understand the process and comprehensively revealing the survival mechanism of bacteria, here we systematically review the studies of the process, regulation and subsequent adaptive results of DNA damage repair. The results show that both endogenous and exogenous pressures can activate the SOS response,especially antibiotics. RecA plays an important role in the process of sensing external pressure and system start-up process, and is also an important regulation target. As a repressor protein,LexA is an inhibitor of the whole response. After the SOS response starts, LexA releases a series of downstream DNA damage repair genes to complete the DNA repair.The adaptive results of SOS response are as follows: DNA precise repair,slowing down or stopping cell division, increasing of chromosome mutation rate, virulence or pathogenicity change, enhanced drug resistance or horizontal transmission of drug-resistance genes. Understanding the whole process of SOS response is helpful to reveal the survival and metabolism process of bacteria adapting to the environment, and lay a theoretical foundation for the prevention and control of pathogenic bacteria.

Abstract:Objective Lung cancer is one of the most commonly diagnosed cancers and the leading cause of cancer deaths worldwide. Despite significant advancements in combined therapy, the numbers of lung cancer cases and deaths continue to rise. Thus, novel therapeutic strategies are necessary to improve cure rates.Methods The effect of concomitant use of deferoxamine and chloroquine with frontline chemotherapy drugs was evaluated in lung cancer cells. The autophagy-dependent degradation of ferritin (i.e. ferritinophagy) was determined by western blot and immunofluorescence. The cell proliferation was quantified by cell member and cell cycle. The mitochondrial oxidative phosphorylation was determined by measuring the cellular oxygen consumption.Results The iron chelator deferoxamine induced ferritinophagy in cancer cells, and this process was blocked by chloroquine, an anti-malaria drug. Exposure of lung cancer cells to deferoxamine and chloroquine together inhibited mitochondrial oxidative phosphorylation, caused the accumulation of G1 phase cells and blocked cell proliferation. More importantly, the use of deferoxamine and chloroquine concomitantly with cisplatin or etoposide resulted in a significant increase in cytotoxicity in lung cancer cells when compared with the same concentration of cisplatin or etoposide alone.Conclusion These data indicate the efficacy of targeting ferritinophagy for the sensitization of iron-addicted cancer cells to chemotherapy, and introduce a potential targeted therapeutic approach for the treatment of cancer.

Abstract:Objective Lung cancer is one of the most common cancers in the world. Lung adenocarcinoma (LUAD) has the highest annual mortality rate among lung cancer patients. It has been reported that changes in gene spectrum were associated with the process of tumorigenesis and its development. The purpose of this study is to identify the gene signatures associated with LUAD and to further analyze their prognostic significance.Methods Weighted gene co-expression network analysis (WGCNA), differential gene analysis, cox regression analysis, and protein-protein interaction (PPI) network analysis were used to screen the hub genes highly related to LUAD based on The Cancer Genome Atlas (TCGA) database. The RNA-seq data sets from TCGA and GTEx (Genotype Tissue Expression) database were combined and divided into a training set and a validation set, which were used to construct the diagnostic model by support vector machine recursive feature elimination feature (SVM-RFE) algorithm. GSE32863 and GSE31210 were used to verify the diagnostic accuracy of the model and the prognostic value of our obtained gene signatures, respectively.Results The results demonstrated that the model of 5 gene signatures (anln, cenpa, plk1, tpx2, cdca3) obtained by the SVM-RFE algorithm had an outstanding performance in the classification of LUAD patients. Functional enrichment analysis showed that these 5 gene signatures were highly related to the biological process of tumor initiation and progression. What’s more, LUAD patients with high expression of these 5 genes also exerted a poor outcome in survival status.Conclusion Therefore, we could conclude that our study obtained useful models with 5 gene signatures for the diagnosis and prognosis of LUAD, which were essential for the development of novel targets applied in precision therapy.

Abstract:Objective In order to analyze the number and morphology of cells in the process of cell culture conveniently.Methods In this paper, we introduce a cell counting method which can directly count cells in culture dish from images of commercial optical microscope by applying deep learning technology.Results In order to implement cell segmentation and counting, labeling and training is carried out on the image of adherent cells and suspension cells by a U-Net structure network. The cell growth curve is plotted and the inhibition rate of inhibitor is calculated by this algorithm, which shows the practicability of the algorithm.Conclusion It is feasible to do cell segmentation in dish by deep learning method.

Abstract:Objective To investigated the function and the target gene of miR-216b in osteoclast differentiation and explored its effect on osteoclast cholesterol efflux.Methods The cell model of RAW264.7 osteoclast precursor cell differentiation induced by RANKL stimulation was established. Tartrate-resistant acid phosphatase (TRAP) staining assay was conducted to evaluate osteoclasts differentiation. MiR-216b target gene, ABCG1 3′ untranslated region (3'UTR) sequence and free energy were predicted and analyzed by bioinformatics analyses and dual-luciferase reporter assays. MiR-216b mimic or inhibitor transfection was performed to verify the role of miR-216b in osteoclast differentiation. Liquid scintillation counting was used to measure [³H]-labeled cholesterol efflux from RAW264.7 macrophage-derived osteoclasts. The lipid accumulation in RAW264.7 macrophages was detected by high performance liquid chromatography (HPLC). Real-time quantitative PCR (RT-qPCR) and Western blot assays were used to assess the transcriptional and post-transcriptional levels of ABCG1 in osteoclasts.Results Our results showed that the number of osteoclasts, the average diameter of osteoclasts and the fusion index were significantly increased when cells were transfected with miR-216b mimic, as revealed by tartrate-resistant acid phosphatase-positive staining and microscopy assay. MiR-216b inhibitor showed the complete opposite outcome which brought additional evidence to our findings. Bioinformatics analysis and dual-luciferase reporter assays showed that miR-216b targets the 3′UTR of ABCG1. Moreover, miR-216b suppressed both the mRNA and protein levels of ABCG1 in osteoclasts. Besides, we found that silencing of ABCG1 by ABCG1 siRNA increased the number of osteoclasts, the average diameter of osteoclasts and the fusion index. MiR-216b reduced cholesterol efflux from osteoclasts by inhibiting ABCG1 expression.Conclusion Collectively, these findings suggest that miR-216b downregulates ABCG1 expression and inhibits osteoclast cholesterol efflux, which disturbs cholesterol homeostasis and promotes osteoclastogenesis.

Abstract:Objective To investigate the effect of two indomethacin preparations on the healing process of oral ulcers.Methods After the right cheek of rats were burned with nails,they were divided into indomethacin gel to medicine group (YN), compound benzocaine gel positive control group (NP), indomethacin spray to medicine group (YP), stomatitis spray, normal control group (PP), positive control group (N) and the negative control group (M). The reepithelialization of ulcer surface and granulation tissue formation was evaluated after HE staining with histological quantitative standard evaluation. The level of nitric oxide (NO) and nitric oxide synthase (NOS) in ulcer tissues was detected by colorimetry. The expressions of epidermal growth factor (EGF), as well as its receptor (EGFR) and vascular endothelial cell growth factor (VEGF) in rat ulcer tissues, were detected by immunohistochemistry.Results The ulcer area of the YP, YN, NP, and PP groups was smaller than that of the M group. The quantitative histological evaluation showed that the scores of the YP, YN, NP, and PP groups were higher than that of the M group (P<0.05). After administration, the level of NO and NOS in the YP group were significantly lower than that of M group (P<0.05). The EGF expression of YP, YN, NP, and PP groups was higher than that of the M and N groups (P<0.05). EGFR was expressed in the epithelium from the cytoplasm to the membrane, and the expression level in the YP, YN, NP, and PP was significantly higher than that of the N group (P<0.05). The VEGF expression of YP, YN, NP, and PP groups was lower than that of the M group (P<0.05).Conclusion Both two indomethacin preparations can reduce the inflammatory response and promote the healing of oral ulcers in rats.

Abstract:Objective Cell mechanics plays an important role in cellular physiological and pathological processes and is closely related to the health states of living organisms. Investigating cell mechanics significantly benefits revealing the underlying mechanisms guiding life activities. The advent of atomic force microscope (AFM) provides a novel instrument for single-cell assay. AFM is able to not only visualize the morphology of singe living cells under aqueous conditions with high resolution, but also quantitatively measure the mechanical properties of cells. Utilizing AFM to investigate the mechanics of individual cells has achieved great success in the past decades, which provides numerous new insights into cellular physiological and pathological processes and has become an important tool in the field of life sciences. However, due to the fact that AFM probe itself is unable to perform drug delivery, so far it is still challenging for the simultaneous measurements of cell mechanics by AFM in response to the stimulation of ultra-trace drug. Here, by combining micropipette and AFM, a method allowing single-cell precise drug delivery and simultaneous measurements of cell mechanics is presented.Methods The micropipette-based single-cell microinjection system was built on an inverted fluorescent microscope by using a 3D manipulator, a micropump, a syringe, a PTFE tube and a micropipette. The micropipette was obtained from the glass capillary by using the micropipette puller. NIH 3T3 cells (mouse embryonic fibroblast), HEK 293 cells (human embryonic kidney cell) and MCF-7 cells (human breast cancer cell) were used for the experiments. Under the guidance of optical microscopy, staining reagents or drug molecules were delivered to individual cells, and then AFM probe was moved to the targeted cells to obtain force curves. Cellular Young’s modulus was calculated from the force curves by applying Hertz-Sneddon model.Results The effects of the pore size of micropipette tip on cell injection were analyzed firstly, and the results showed that larger pore size tip (the outer diameter of the tip was larger than 1 μm) could cause obvious mechanical damage to the cell. Then blue ink or PI staining solution was injected to single cells by micropipette under the guidance of optical microscopy, and the recorded optical/fluorescent images after injection clearly showed that the targeted cells were successfully injected. Finally, micropipette was integrated with AFM to measure the Young’s modulus changes of single cells after the treatment of chemotherapeutic drug (cytarabine), and the results showed that stimulation of cytarabine could cause the changes of cellular mechanical properties.Conclusion Combining micropipette and AFM enables applying precise chemical stimulation to a single cell while simultaneously measuring cellular mechanical properties after chemical stimulation, providing a novel idea for single-cell mechanical analysis in response to ultra-trace drugs.

Abstract:Objective With the rapid development of the bio-industry, more and more biological enterprises, mainly biomedical enterprises, have emerged. How to promote the output efficiency of biological enterprises is the most concern of the government and enterprises themselves.Methods This paper constructs a DEA model to evaluate the input-output efficiency of 370 listed companies in China’s biological industry.Results The research results show that the average comprehensive technical efficiency of listed companies in China"s biological industry is 0.596, and there is still much room for improvement.Conclusion The main factor restricting the overall technical efficiency of listed companies in China’s biological industry is pure technical efficiency. Large-scale listed biological companies should optimize investment and reduce redundancy, while smaller-scale listed biological companies need to expand their scale.