Abstract:Bioorthogonal chemistry reaction is a kind of chemical reaction that can occur under physiological conditions, which has been widely used in biomedical research field owing to its high efficiency, specificity and simplicity. Metabolic engineering based on metabolic biosynthesis pathway is a reliable modification technique, achieving the non-destructive and efficient labeling of living molecules. The various chemical reporter groups could be effectively introduced into target biomolecules via biological metabolic process, which allowing the targets were labeled with complementary probes through bioorthogonal reaction for molecular labeling and drug delivery in living systems. Combined the advantages of metabolic engineering and bioorthogonal chemistry, this labeling strategy has great application potential and research value in labeling, trace imaging and diagnosis in the fields of biomedical engineering. Herein we introduced the theory and research progress of bioorthogonal chemistry and metabolic engineering in biomedical fields, and also specially analyzed the application of bioorthogonal chemistry in molecular imaging and drug delivery.

Abstract:Exosomes are nanoscale extracellular vesicles secreted by cells, which mediate cell-to-cell communication by releasing their biologically active molecules, such as microRNAs (miRNAs), into recipient cells. MiRNAs, a class of non-coding RNAs which mainly negatively regulate their target mRNAs at the post-transcriptional level, are the most abundant nucleic acids in exosomes. In lung cancer, miRNAs play a vital role after their release by exosomes secreted by tumor cells. This review mainly focuses on the role of exosomal miRNAs in multistep development of lung cancer, including angiogenesis, cell proliferation, invasion and metastasis, immune escape, drug resistance, as well as their clinical value as a new biomarker for the diagnosis and prognosis of lung cancer.

Abstract:The pre-mRNA of eukaryotic cells must undergo extensive and complex processes to produce mature mRNAs, including 5" end capping, splicing and 3" end processing. Among them, 3" end processing includes cleavage and polyadenylation, which is controlled by the cis-elements of pre-mRNA and a number of protein factors. Mammalian 3" end processing machinery consists of cleavage and polyadenylation factors, cleavage and stimulating factors, cleavage factor Ⅰ and cleavage factor Ⅱ. Other protein factors include poly(A) polymerase, poly(A) binding protein, symplekin and so on. Mammalian genes usually contain multiple polyadenylation sites, and alternative polyadenylation can not only produce mRNA variants with different length of 3"UTR, but also change the CDS region of genes. As a key mechanism for the regulation of gene expression in eukaryotes, alternative polyadenylation plays an important role in cell growth, proliferation and differentiation. This paper reviews the formation of the 3" end of mammalian pre-mRNA, the composition and function of the 3" end processing machinery, the mechanism of alternative polyadenylation in various human diseases, and hope to bring some new insights to readers.

Abstract:Autophagy is an evolutionary conserved cellular process that delivers the intracellular components to lysosome for degradation and recycling, which is tightly regulated by multiple pathways. This catabolic process involves the renewal of organelles, the removal of misfolded proteins and protein aggregates as well as the elimination of pathogens in cells. Therefore, autophagy is critical to maintain cellular homeostasis and closely related to the development of many human diseases. With the deepening of the mechanism research of autophagy regulation, more and more deubiquitinating enzymes have been proved to play an important role in autophagy-related ubiquitin signaling system. These enzymes can act at different stages of autophagy, and target different ubiquitinated machinery components or substrates of autophagy. As the therapeutic targets for autophagy-related diseases including neurodegeneration diseases and tumors, deubiquitinating enzymes have attracted extensive attention. The discovery of various small-molecule inhibitors provides the possibility to further study the autophagy regulatory activity of the ubiquitinases and also the treatment of related diseases.

Abstract:Breast cancer is a malignant tumor which can seriously endanger women"s health. The detection of its pathogenic genes is helpful for the early detection, accurate treatment and prognosis evaluation of the tumor. This paper summarizes the hot biomarkers related to breast cancer in recent years and reviews the molecular diagnostic techniques, detection methods and applications of related genes. The development of digital PCR in molecular detection of breast cancer was reviewed for the first time. The advantages and disadvantages of different molecular diagnostic techniques were comprehensively compared in this paper. It provides a guidance for the detection of oncogenes in breast cancer, and makes a forecast for future trends.

Abstract:The nociceptin receptor is another new type of opioid receptor found after mu-opioid receptor, kappa-opioid receptor and delta-opioid receptor, which not only has structural similar features to classical opioid receptors, but also mediates same or similar intracellular biological response. Nociceptin receptor has a unique modulation of pain response. On the one hand, it usually exerts the analgesic effect at the dorsal root ganglia and spinal cord levels, and synergistic with other opioid receptors at the level of the spinal cord to enhance the analgesic effect. On the other hand, at the level of the spinal cord, nociceptin receptor produces hyperalgesia that antagonizes the analgesic effects of other opioid receptors. In addition, the regulation of pain sensation by nociceptin receptors also shows some differences among different species. This provides a theoretical basis for further elucidation of the pain regulation of the endogenous opioid system.

Abstract:This study was aimed to investigate the feasibility of using simulated microgravity to study the effects of microgravity on activity and sleep of Drosophila melanogaster. Simulated microgravity experiments performed using the random positioning machine (RPM) and male Drosophila melanogaster, and the activity and sleep of the flies were monitored using the DAM system (Trikinetics, USA). First, flies were exposed to simulated microgravity for a short time (3 days) with DAM system monitoring. Next, after being exposed to simulated microgravity for a long time (10, 20, and 30 days), flies were removed to be monitored for 3 consecutive days under control conditions. Then, the flies after short-term treatment (3 days) with greater impact were sampled to study the effects of simulated microgravity on the major circadian clock genes period (per), timeless (tim), clock (clk), cycle (cyc), cryptochrome (cry), and ddc, pale, trh genes encoding dopa decarboxylase, tyrosine hydroxylase, tryptophan hydroxylase, that involved in synthesis of neurotransmitter dopamine (DA) and 5-hydroxy-tryptamine (5-HT), and the contents of DA and 5-HT. The results showed that during short-term treatment, total activity accounts and activity accounts in wake period both increased, and total sleep and number of sleep episode both decreased at night; after short-term treatment, the relative expression levels of tim, clk, cyc and cry increased, and the relative expression levels of ddc, pale and trh increased; after long-term treatment, overall effect on activity and sleep was slight. This study suggests that it is feasible to study the effects of microgravity on activity and sleep of Drosophila melanogaster by simulated microgravity, and valuable reference can be provided for aerospace medical research.

Abstract:In order to screen the optimal culture system for Vero cell culture, this study has optimized the culture medium, passage ratio and density for three consecutive passage respectively. Above all, Vero cells were cultured in different kinds of medium for three passages to select the best medium. Subsequently, different subculture density and proportion of Vero cells were cultured in the optimal medium for three passage, and the optimized passage ratio win out. In general, 1.296% MEM medium supplied with superfine fetal bovine serum is better than the other combination of medium and it can sustain the successive stable culture passaging. In the condition of this medium, the best proportion of cell passaging is 1∶6 and the optimal cell density is 3×10⁴/cm². In this study, we screened the conditions of the best Vero cell culture system and confirmed that the conditions meet the continuous and stable passage of Vero cells.