Immobilized enzyme-based enzyme electrode biosensors, characterized by high sensitivity and efficiency, strong specificity, and compact size, demonstrate broad application prospects in life science research, disease diagnosis and monitoring, etc. Immobilization of enzyme is a critical step in determining the performance (stability, sensitivity, and reproducibility) of the biosensors. Random immobilization (physical adsorption, covalent cross-linking, etc.) can easily bring about problems, such as decreased enzyme activity and relatively unstable immobilization. Whereas, directional immobilization utilizing amino acid residue mutation, affinity peptide fusion, or nucleotide-specific binding to restrict the orientation of the enzymes provides new possibilities to solve the problems caused by random immobilization. In this paper, the principles, advantages and disadvantages and the application progress of enzyme electrode biosensors of different directional immobilization strategies for enzyme molecular sensing elements by specific amino acids (lysine, histidine, cysteine, unnatural amino acid) with functional groups introduced based on site-specific mutation, affinity peptides (gold binding peptides, carbon binding peptides, carbohydrate binding domains) fused through genetic engineering, and specific binding between nucleotides and target enzymes (proteins) were reviewed, and the application fields, advantages and limitations of various immobilized enzyme interface characterization techniques were discussed, hoping to provide theoretical and technical guidance for the creation of high-performance enzyme sensing elements and the manufacture of enzyme electrode sensors.

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. In terms of application, it focuses on the use of animal disease models exploring the application effects of recombinant collagen in wound hemostasis, wound repair, corneal therapy, female pelvic floor dysfunction (FPFD), vaginal atrophy (VA) and vaginal dryness, thin endometritis (TE), chronic endometritis (CE), bone tissue regeneration in vivo, cardiovascular diseases, breast cancer (BC) and anti-aging. The mechanism of action of recombinant collagen in the treatment of FPFD and CE was introduced, and the clinical application and curative effect of recombinant collagen in skin burn, skin wound, dermatitis, acne and menopausal urogenital syndrome (GSM) were summarized. 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 faced by 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.

ObjectiveTo characterize the seasonal patterns of influenza in Kunming City, Yunnan Province before, during, and after the COVID-19 pandemic, and provide scientific evidence for optimizing influenza prevention and control strategies. MethodsInfluenza-like illness (ILI) and etiological surveillance data for influenza from the 14^th week of 2010 to the 13^th week of 2024 in Kunming City of Yunnan Province were collected. Harmonic regression models were constructed to analyze the epidemic characteristics and seasonal patterns of influenza before (2010/2011‒2019/2020 influenza seasons), during (2020/2021‒2022/2023 influenza seasons), and after (2023/2024 influenza season) the COVID-19 pandemic. ResultsBefore the COVID-19 pandemic, influenza in Kunming City mainly exhibited an annual cyclic pattern without a significant semi-annual periodicity, peaking from December to February of the next year, with an epidemic duration of 20‒30 weeks. During the pandemic, influenza seasonality shifted, with an increase in semi-annual periodicity and an approximate one month delay in annual peaks. However, after the pandemic, the annual amplitude of influenza increased compared with that before the pandemic, and the epidemic duration extended by about one month. Although the annual peak largely reverted to the pre-pandemic levels, the annual peaks for different influenza subtypes/lineages had not fully recovered. ConclusionInfluenza seasonality in Kunming City underwent substantial alterations following the COVID-19 pandemic and has not yet fully reverted to pre-pandemic levels. Continuous surveillance on different subtypes/lineages of influenza viruses remains essential, and prevention and control strategies should be adjusted and optimized in a timely manner based on current epidemic trends.

OBJECTIVE To study the interventional effect and mechanism of 1，8-cineole on pancreatic β cell ferroptosis induced by type 2 diabetes. METHODS In vitro ferroptosis model was established in pancreatic β cells of mice by using high glucose. The effects of low-dose and high-dose 1，8-cineole （0.25， 0.5 μmol/L） on the level of Fe2+ in pancreatic β cells were investigated. The effects of 1，8-cineole （0.5 μmol/L） combined with ferroptosis inducer Erastin （20 μmol/L） and ferroptosis inhibitor Ferrostatin-1 （20 μmol/L） on the protein expressions of glutathione peroxidase-4 （GPX4） and cyclooxygenase-2 （COX2） were also detected. The type 2 diabetes model mice were established by feeding high-sugar and high-fat diet combined with intraperitoneal injection of streptozotocin. The effects of low-dose and high-dose 1，8-cineole （50， 200 mg/kg） on the pathological morphology of pancreatic tissue， the content of iron as well as the protein expressions of GPX4 and COX2 were investigated. RESULTS The results of the cell experiment showed that compared with the model group， pretreatment with 1，8-cineole significantly reduced intracellular Fe2+ levels and upregulated GPX4 protein expression， while downregulated COX2 protein expression in pancreatic β cells （P＜0.05）. After combining with Ferrostatin-1， the expression trends of the above two proteins were the same， while there was no statistically significant difference after combining with Erastin. The results of animal experiments showed that compared with the model group， after intervention with 1，8-cineole， the structure of the pancreatic islets in mice recovered intact and their morphology improved； the iron content of pancreatic tissue and protein expression of COX2 were decreased significantly （P＜0.05）， while protein expression of GPX4 was increased significantly （P＜0.05）. CONCLUSIONS 1，8-cineole could ameliorate pancreatic β cell injury induced by diabetes， the mechanism of which may be related to reducing intracellular iron deposition and regulating ferroptosis-related proteins.

The assessment of adverse drug events is an important basis for clinical safety evaluation and post-marketing risk control of drugs,and its causality assessment is gaining increasing attention.The existing methods for assessing the causal relationship between drugs and the occurrence of adverse reactions can be broadly classified into three categories:global introspective methods,standardized methods,and probabilistic methods.At present,there is no systematic introduction of the operational details of the various methods in the domestic literature.This paper compares representative causality assessment methods in terms of definition and concept,methodological steps,industry evaluation and advantages and disadvantages,clarifies the basic process of determining the causality of adverse drug reactions,and discusses how to further improve the adverse drug reaction monitoring and evaluation system,with a view to providing a reference for drug development and pharmacovigilance work in China.

Objective To investigate the effect of quercetin on HCE-2 injury of human corneal epithelial cells induced by high osmotic pressure and its mechanism.Methods HCE-2 cells were randomly divided into control group(normal osmotic pressure),model group(high osmotic pressure),experimental-L group(high osmotic pressure+31.25 pg·mL-1 quercetin),experimental-M group(high osmotic pressure+62.50 μg·mL-1 quercetin),experimental-H group(high osmotic pressure+125.00 μg·mL-1 quercetin),erastin group(high osmotic pressure+125.00 μg·mL-1 quercetin+30.00 μmol·L-1 iron death inducer erastin).Cell survival rate was detected by cell counting kit 8;reactive oxygen species(ROS)levels was detected by C11-BODIPY 581/591 probe staining;glutathione(GSH)and malondialdehyde(MDA)levels were determined by kit method;the expression levels of glutathione peroxidase 4(GPX4),dihydrolactate dehydrogenase(DHODH)and ferroptosis suppressor protein 1(FSP1)were detected by real-time quantitative polymerase chain reaction and Western blot.Results The cell survival rates of control group,model group,experimental-H group and erastin group were(100.00±3.97)％,(50.05±5.83)％,(86.35±7.35)％and(58.32±4.66)％,respectively;ROS levels were 1.00±0.09,2.45±0.16,1.19±0.05 and 2.09±0.30,respectively;GPX4 protein levels were 1.09±0.11,0.34±0.03,0.91±0.12 and 0.30±0.04,respectively;FSP1 protein levels were 0.92±0.06,0.25±0.03,0.89±0.07 and 0.39±0.07,respectively;DHODH protein levels were 0.89±0.11,0.31±0.04,0.86±0.11,0.41±0.04,respectively.Compared with model group,the above indexes in control group were statistically significant(all P＜0.05);the differences between experimental-H group and model group were statistically significant(all P＜0.05);the above indexes in erastin group were significantly different from those in experimental-H group(all P＜0.05).Conclusion Quercetin can ameliorate HCE-2 cell damage induced by high osmotic pressure by inhibiting iron death pathway.

Objective To explore the protective mechanism of honey-processed Hedysari Radix in regulating intestinal mucosal injury in rats with spleen qi deficiency.Methods The three-factor composite modeling method of bitter cold diarrhea,overwork and hunger and satiety disorder was used to construct a spleen qi deficiency model rats.After the model was successfully made,they were randomly divided into model group,honey-processed Hedysari Radix group and probiotic group,with 15 animals in each group.Another 15 normal rats were taken as the blank group.The honey-processed Hedysari Radix group was given 12.6 g·kg-1 water decoction of honey-processed Hedysari Radix by gavage,the probiotics group was given Bifidobacterium Lactobacillus triple viable tablets suspension at a dose of 0.625 g·kg-1,and the blank group and the model group were given the same dose of distilled water.The rats in the four groups were administered once a day for 15 days.Enzyme-linked immunosorbent assay was used to detect diamine oxidase(DAO)in serum,D-lactic acid(D-LA),secretory immunoglobulin A factor,and Western blotting was used to detect the expression levels of AMP-activated protein kinase(AMPK),zonula occludens-1(ZO-1)and occludin in colon tissues.Results The serum levels of DAO in the blank group,model group,honey-processed Hedysari Radix group and probiotic group were(138.93±9.78),(187.95±12.90),(147.21±6.92)and(166.47±3.37)pg·mL-1;the contents of D-LA were(892.23±49.17),(1 099.84±137.64),(956.56±86.04)and(989.61±51.75)μg·L-1;the contents of SIgA in colon tissues were(14.04±1.42),(11.47±2.39),(11.84±1.49)and(12.93±1.65)μg·mL-1;the relative expression levels of ZO-1 protein in colon tissues were 1.18±0.11,0.42±0.04,0.77±0.05 and 0.95±0.07;the relative expression levels of occludin protein were 1.35±0.31,0.61±0.17,1.19±0.19 and 0.88±0.13;the relative expression levels of AMPK protein were 0.91±0.02,0.35±0.09,0.74±0.08 and 0.59±0.11.Compared with the model group,there were significant differences in the serum content of DAO and D-LA,SIgA content in colon,and the content of ZO-1,occludin and AMPK protein in the honey-processed Hedysari Radix group(P＜0.01,P＜0.05).Conclusion Honey-processed Hedysari Radix can enhance the protective effect on the intestinal mucosa of rats with spleen qi deficiency by regulating the expression of related inflammatory cytokines,intestinal mucosal upper cell enzymes and tight junction proteins in rats with spleen qi deficiency.

Retrograde adeno-associated viruses (AAVs) are capable of infecting the axons of projection neurons and serve as a powerful tool for the anatomical and functional characterization of neural networks. However, few retrograde AAV capsids have been shown to offer access to cortical projection neurons across different species and enable the manipulation of neural function in non-human primates (NHPs). Here, we report the development of a novel retrograde AAV capsid, AAV-DJ8R, which efficiently labeled cortical projection neurons after local administration into the striatum of mice and macaques. In addition, intrastriatally injected AAV-DJ8R mediated opsin expression in the mouse motor cortex and induced robust behavioral alterations. Moreover, AAV-DJ8R markedly increased motor cortical neuron firing upon optogenetic light stimulation after viral delivery into the macaque putamen. These data demonstrate the usefulness of AAV-DJ8R as an efficient retrograde tracer for cortical projection neurons in rodents and NHPs and indicate its suitability for use in conducting functional interrogations.
Animals ; Haplorhini ; Axons ; Motor Neurons ; Interneurons ; Macaca ; Dependovirus/genetics* ; Genetic Vectors

Studies have suggested that the nucleus accumbens (NAc) is implicated in the pathophysiology of major depression; however, the regulatory strategy that targets the NAc to achieve an exclusive and outstanding anti-depression benefit has not been elucidated. Here, we identified a specific reduction of cyclic adenosine monophosphate (cAMP) in the subset of dopamine D1 receptor medium spiny neurons (D1-MSNs) in the NAc that promoted stress susceptibility, while the stimulation of cAMP production in NAc D1-MSNs efficiently rescued depression-like behaviors. Ketamine treatment enhanced cAMP both in D1-MSNs and dopamine D2 receptor medium spiny neurons (D2-MSNs) of depressed mice, however, the rapid antidepressant effect of ketamine solely depended on elevating cAMP in NAc D1-MSNs. We discovered that a higher dose of crocin markedly increased cAMP in the NAc and consistently relieved depression 24 h after oral administration, but not a lower dose. The fast onset property of crocin was verified through multicenter studies. Moreover, crocin specifically targeted at D1-MSN cAMP signaling in the NAc to relieve depression and had no effect on D2-MSN. These findings characterize a new strategy to achieve an exclusive and outstanding anti-depression benefit by elevating cAMP in D1-MSNs in the NAc, and provide a potential rapid antidepressant drug candidate, crocin.

The anti-inflammatory effect of simplified Zhiqin Decoction was observed by using lipopolysaccharide (LPS)-induced inflammation mouse model. The main chemical constituents and the main mechanism of action of simplified Zhiqin Decoction were predicted by network pharmacology. Animal experiments verified the anti-inflammatory mechanism of simplified Zhiqin Decoction (this experiment was approved by the Animal Experiment Ethics Committee of Southwest University, approval number: IACUC-20210825-02). Simplifying Zhiqin Decoction has a significant anti-inflammatory effect on inflammatory mice, can significantly improve the overall macro shape of mice, reduce body temperature, water intake, increase the number of autonomous activities; alleviate liver, lung, spleen, thymus inflammation and pathological damage; decrease tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6, nitric oxide (NO), prostaglandin E₂ (PGE₂) content in serum and urine. The contents of serum immune factors IgG, IgA and IgM were increased. Network pharmacology predicted 66 potential anti-inflammatory active components of simplified Zhiqin Decoction involving 132 inflammatory targets, and the key anti-inflammatory signaling pathway involved PI3K/AKT, TNF, JAK-STAT, etc. Animal experiments show that simplified Zhiqin Decoction can significantly reduce the expression of JAK2/STAT-PI3K/AKT-NF-κB-TNF signaling pathway related proteins in lung tissue of inflammatory mice. The results of this study showed that simplified Zhiqin Decoction had significant anti-inflammatory effects, and its main anti-inflammatory components were quercetin, β-sitosterol, kaempferol, wogonin, stigmasterol, luteolin, neobaicalein, etc. The main mechanism of its anti-inflammatory action is that it significantly inhibits the expression of JAK2/STAT-PI3K/AKT-NF-κB-TNF signaling pathway protein.