1.The Structure and Function of The YopJ Family Effectors in The Bacterial Type III Secretion System
Ao-Ning LI ; Wen-Bo LI ; Yu-Ying LU ; Min-Hui ZHU ; Yu-Long QIN ; Yong ZHAO ; Zhao-Huan ZHANG
Progress in Biochemistry and Biophysics 2026;53(3):516-533
The Type III Secretion System (T3SS) serves as a pivotal virulence apparatus for numerous Gram-negative bacterial pathogens, enabling them to infect both animal and plant hosts. Functioning as a molecular syringe, the T3SS directly translocates bacterial effector proteins from the bacterial cytoplasm into the interior of eukaryotic host cells. These effectors are central weapons that precisely manipulate a wide spectrum of host cellular physiological processes, ranging from cytoskeletal dynamics to immune signaling, to establish a favorable niche for bacterial survival and proliferation. Among the diverse arsenal of T3SS effectors, the YopJ family constitutes a critical group of virulence factors. Members of this family are characterized by a conserved catalytic triad structure—a hallmark of the CE clan of cysteine proteases that has been evolutionarily repurposed to confer acetyltransferase activity. A defining and intriguing feature of these enzymes is their stringent dependence on a host-derived eukaryotic cofactor, inositol hexakisphosphate (IP6), for allosteric activation. This requirement acts as a sophisticated molecular safeguard, ensuring enzymatic activity only within the appropriate host environment, thereby preventing detrimental effects on the bacterium itself. While seminal studies on individual members such as Yersinia’s YopJ and Salmonella’s AvrA have provided deep mechanistic insights, a systematic and integrative understanding of the structure-function relationships across the entire family remains fragmented. Key questions persist regarding how a conserved catalytic core has diverged to recognize distinct host substrates in different kingdoms of life. To address this gap, this article provides a systematic review of the YopJ family, focusing on three interconnected aspects: their structural features, their catalytic mechanism, and their divergent immunosuppressive strategies in animal versus plant hosts. By conducting a comparative analysis of the sequences and resolved three-dimensional structures of three representative members (e.g., HopZ1a, PopP2, AvrA), we elucidate regions of significant variation embedded within the conserved core catalytic architecture. These variable regions, often involving surface loops and substrate-binding interfaces, are crucial determinants of target specificity and functional specialization. The functional divergence of this effector family is most apparent when comparing their modes of action in different hosts. In animal hosts, YopJ-family effectors primarily sabotage innate immune signaling pathways. They achieve this by acetylating key serine and threonine residues within the activation loops of critical kinases in the MAPK and NF‑κB pathways. This post-translational modification blocks the phosphorylation and subsequent activation of these kinases, leading to potent suppression of inflammatory cytokine production. Conversely, in plant hosts, the strategy broadens to dismantle the two-tiered plant immune system. YopJ homologs target a more diverse set of substrates, including immune-associated receptor-like cytoplasmic kinases (RLCKs), microtubule networks via tubulin acetylation (which disrupts cellular trafficking and signaling), and transcription factors central to defense gene regulation. This multi-target approach effectively suppresses both Pattern-Triggered Immunity (PTI) and Effector-Triggered Immunity (ETI). In conclusion, this synthesis aims to deepen the mechanistic understanding of YopJ family-mediated pathogenesis by integrating structural biology with cellular function across host kingdoms. Elucidating the precise molecular basis for substrate selection—how conserved platforms achieve target diversity—is a major frontier. Furthermore, this knowledge provides a vital theoretical foundation for developing novel anti-virulence strategies. Targeting the conserved IP6-binding pocket or the catalytic acetyltransferase activity itself represents a promising avenue for designing broad-spectrum inhibitors that could disarm this critical family of bacterial effectors, potentially offering new therapeutic approaches against a range of pathogenic bacteria.
2.Herbal Textual Research on Quisqualis Fructus in Famous Classical Formulas
Xiuping WEN ; Shiying CHEN ; Ying TAN ; Guanwen ZHENG ; Huilong XU ; Wen XU ; Chengzi YANG ; Zehao HUANG ; Yu LIN ; Zhilai ZHAN
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(6):225-237
This article systematically analyzed the historical evolution of the origin, scientific name, producing area, quality evaluation, harvesting and processing, and other aspects of Quisqualis Fructus by consulting the ancient materia medica, medical books, prescription books, local literature and combining with the modern literature and standards, summarized and explored the development rules of its medicinal properties and efficacy along with their underlying causes, in order to provide support for the development and utilization of famous classical formulas containing this herb. According to the textual research, Shijunzi was first recorded as Liuqiuzi in Nanfang Caomuzhuang of the Jin dynasty, and the name of Shijunzi was first used in Kaibao Bencao of the Song dynasty, which has been consistently used throughout subsequent dynasties, and there were also aliases such as Junziren, Sijunzi, and Dujilizi. The mainstream source of Quisqualis Fructus used in the past dynasties has been the dried mature fruits of Quisqualis indica, a plant belonging to the family Combretaceae. In modern times, its variety Q. indica var. villosa has also been recorded as the medicinal material of Quisqualis Fructus. In 2007, the Flora of China(English edition) designated Q. indica var. villosa as a synonym of Q. indica. Today, the accepted name of Shijunzi is updated to Combretum indicum. According to ancient herbal records, the producing areas of Quisqualis Fructus were Guangdong, Hong Kong, Macao, Guangxi, Hainan, Sichuan and Fujian, and then gradually expanded to Yunnan, Taiwan, Jiangxi and Guizhou. Since the Song dynasty, two major production regions have gradually emerged in Sichuan, Chongqing and Fujian. Currently, it is primarily cultivated in Chongqing, Guangxi and other areas, with Chongqing yielding the highest output. Since modern times, superior quality has been defined by large size, a purple-black surface, plump grains, and a yellowish-white kernel. According to ancient herbal records, the harvesting period of Quisqualis Fructus was the July and August of the lunar calendar, mostly used raw after shelling or with the shell intact, it underwent processing methods such as cleaning, slicing, mixing, steaming, roasting, stewing, and frying. Currently, the harvesting period is autumn, followed by sun-drying or low-heat drying, with processing methods including cleaning, stir-frying, and stewing. In ancient and modern literature, the records of the properties, functions and indications of Quisqualis Fructus are basically the same, that is, sweet in taste, warm in nature, predominantly non-toxic, belonging to the spleen and stomach meridians. It possesses effects of insecticide, decontamination and invigorating spleen for ascariasis, enterobiasis, abdominal pain due to worm accumulation and infantile malnutrition.The contraindications for use primarily include avoiding consumption by individuals without parasitic infestations, limiting use for those with spleen-stomach deficiency-cold, refraining from drinking hot tea during medication, and avoiding excessive intake. Based on the textual research, it is suggested that the dried mature fruits of Q. indica should be used as the medicinal material for the development of famous classical formulas containing Quisqualis Fructus. Processing methods may be chosen according to prescription requirements, and the raw products is recommended for medicinal use if not specified.
3.Identification of GSK3 family and regulatory effects of brassinolide on growth and development of Nardostachys jatamansi.
Yu-Yan LEI ; Zheng MA ; Jing WEI ; Wen-Bing LI ; Ying LI ; Zheng-Ming YANG ; Shao-Shan ZHANG ; Jing-Qiu FENG ; Hua-Chun SHENG ; Yuan LIU
China Journal of Chinese Materia Medica 2025;50(2):395-403
This study identified 8 members including NjBIN2 of the GSK3 family in Nardostachys jatamansi by bioinformatics analysis. Moreover, the phylogenetic tree revealed that the GKS3 family members of N. jatamansi had a close relationship with those of Arabidopsis. RT-qPCR results showed that NjBIN2 presented a tissue-specific expression pattern with the highest expression in roots, suggesting that NjBIN2 played a role in root growth and development. In addition, the application of epibrassinolide or the brassinosteroid(BR) synthesis inhibitor(brassinazole) altered the expression pattern of NjBIN2 and influenced the photomorphogenesis(cotyledon opening) and root development of N. jatamansi, which provided direct evidence about the functions of NjBIN2. In conclusion, this study highlights the roles of BIN2 in regulating the growth and development of N. jatamansi by analyzing the expression pattern and biological function of NjBIN2. It not only enriches the understanding about the regulatory mechanism of the growth and development of N. jatamansi but also provides a theoretical basis and potential gene targets for molecular breeding of N. jatamansi with improved quality in the future.
Brassinosteroids/metabolism*
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Steroids, Heterocyclic/metabolism*
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Gene Expression Regulation, Plant/drug effects*
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Plant Proteins/metabolism*
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Phylogeny
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Nardostachys/metabolism*
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Plant Growth Regulators/pharmacology*
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Plant Roots/drug effects*
4.Pharmacokinetics and anti-inflammatory activity of cannabidiol/ γ-polyglutamic acid-g-cholesterol nanomicelles.
Rui LI ; Li-Yan LU ; Chu XU ; Rui HAO ; Xiao YU ; Rui GUO ; Jue CHEN ; Wen-Hui RUAN ; Ying-Li WANG
China Journal of Chinese Materia Medica 2025;50(2):534-541
In this study, the pharmacokinetic characteristics and tissue distribution of cannabidiol(CBD)/γ-polyglutamic acid-g-cholesterol(γ-PGA-g-CHOL) nanomicelles [CBD/(γ-PGA-g-CHOL)NMs] were investigated by pharmacokinetic experiments, and the effect of CBD/(γ-PGA-g-CHOL)NMs on the lipopolysaccharide(LPS)-induced inflammatory damage of cells was evaluated by cell experiments. CBD/(γ-PGA-g-CHOL)NMs were prepared by dialysis. The CBD concentrations in the plasma samples of male SD rats treated with CBD and CBD/(γ-PGA-g-CHOL)NMs were investigated, and the pharmacokinetic parameters were calculated and compared. UPLC-MS/MS was employed to determine the concentration of CBD in tissue samples. The heart, liver, spleen, lung, kidney, and muscle samples were collected at different time points to explore the tissue distribution of CBD and CBD/(γ-PGA-g-CHOL)NMs. The Caco-2 cell model of LPS-induced inflammation was established, and the cell viability, transepithelial electrical resistance(TEER), and secretion levels of inflammatory cytokines were determined to compare the anti-inflammatory activity between the two groups. The results showed that CBD/(γ-PGA-g-CHOL)NMs had the average particle size of(163.1±2.3)nm, drug loading of 8.78%±0.28%, and encapsulation rate of 84.46%±0.35%. Compared with CBD, CBD/(γ-PGA-g-CHOL)NMs showed increased peak concentration(C_(max)) and prolonged peak time(t_(max)) and mean residence time(MRT_(0-t)). Within 24 h, the tissue distribution concentration of CBD/(γ-PGA-g-CHOL)NMs was higher than that of CBD. In addition, both CBD and CBD/(γ-PGA-g-CHOL)NMs significantly enhanced Caco-2 cell viability and TEER, lowered the secretion levels of inflammatory cytokines, and alleviated inflammation. Moreover, CBD/(γ-PGA-g-CHOL)NMs demonstrated stronger anti-inflammatory effect. It can be inferred that γ-PGA-g-CHOL blank nanomicelles are good carriers of CBD, being capable of prolonging the circulation time of CBD in the blood, improving the bioavailability and tissue distribution concentration of CBD, and protecting against LPS-induced inflammatory injury. The findings can provide an experimental basis for the development and clinical application of oral CBD preparations.
Animals
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Cannabidiol/administration & dosage*
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Polyglutamic Acid/analogs & derivatives*
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Humans
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Male
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Rats
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Rats, Sprague-Dawley
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Anti-Inflammatory Agents/administration & dosage*
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Micelles
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Caco-2 Cells
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Cholesterol/pharmacokinetics*
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Tissue Distribution
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Nanoparticles/chemistry*
5.Verification of resveratrol ameliorating vascular endothelial damage in sepsis-associated encephalopathy through HIF-1α pathway based on network pharmacology and experiment.
Rong LI ; Yue WU ; Wen-Xuan ZHU ; Meng QIN ; Si-Yu SUN ; Li-Ya WANG ; Mei-Hui TIAN ; Ying YU
China Journal of Chinese Materia Medica 2025;50(4):1087-1097
This study aims to investigate the mechanism by which resveratrol(RES) alleviates cerebral vascular endothelial damage in sepsis-associated encephalopathy(SAE) through network pharmacology and animal experiments. By using network pharmacology, the study identified common targets and genes associated with RES and SAE and constructed a protein-protein interaction( PPI) network. Gene Ontology(GO) analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis were performed to pinpoint key signaling pathways, followed by molecular docking validation. In the animal experiments, a cecum ligation and puncture(CLP) method was employed to induce SAE in mice. The mice were randomly assigned to the sham group, CLP group, and medium-dose and high-dose groups of RES. The sham group underwent open surgery without CLP, and the CLP group received an intraperitoneal injection of 0. 9% sodium chloride solution after surgery. The medium-dose and high-dose groups of RES were injected intraperitoneally with 40 mg·kg-1 and 60 mg·kg~(-1) of RES after modeling, respectively, and samples were collected 12 hours later. Neurological function scores were assessed, and the wet-dry weight ratio of brain tissue was detected. Serum superoxide dismutase(SOD), catalase( CAT) activity, and malondialdehyde( MDA) content were measured by oxidative stress kit. Histopathological changes in brain tissue were examined using hematoxylin-eosin(HE) staining. Transmission electron microscopy was employed to evaluate tight cell junctions and mitochondrial ultrastructure changes in cerebral vascular endothelium. Western blot analysis was performed to detect the expression of zonula occludens1( ZO-1), occludin, claudins-5, optic atrophy 1( OPA1), mitofusin 2(Mfn2), dynamin-related protein 1(Drp1), fission 1(Fis1), and hypoxia-inducible factor-1α(HIF-1α). Network pharmacology identified 76 intersecting targets for RES and SAE, with the top five core targets being EGFR, PTGS2, ESR1, HIF-1α, and APP. GO enrichment analysis showed that RES participated in the SAE mechanism through oxidative stress reaction. KEGG enrichment analysis indicated that RES participated in SAE therapy through HIF-1α, Rap1, and other signaling pathways. Molecular docking results showed favorable docking activity between RES and key targets such as HIF-1α. Animal experiment results demonstrated that compared to the sham group, the CLP group exhibited reduced nervous reflexes, decreased water content in brain tissue, as well as serum SOD and CAT activity, and increased MDA content. In addition, the CLP group exhibited disrupted tight junctions in cerebral vascular endothelium and abnormal mitochondrial morphology. The protein expression levels of Drp1, Fis1, and HIF-1α in brain tissue were increased, while those of ZO-1, occludin, claudin-5, Mfn2, and OPA1 were decreased. In contrast, the medium-dose and high-dose groups of RES showed improved neurological function, increased water content in brain tissue and SOD and CAT activity, and decreased MDA content. Cell morphology in brain tissue, tight junctions between endothelial cells, and mitochondrial structure were improved. The protein expressions of Drp1, Fis1, and HIF-1α were decreased, while those of ZO-1, occludin, claudin-5, Mfn2, and OPA1 were increased. This study suggested that RES could ameliorate cerebrovascular endothelial barrier function and maintain mitochondrial homeostasis by inhibiting oxidative stress after SAE damage, potentially through modulation of the HIF-1α signaling pathway.
Animals
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Mice
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Network Pharmacology
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Resveratrol/administration & dosage*
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Male
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Sepsis-Associated Encephalopathy/genetics*
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Signal Transduction/drug effects*
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Hypoxia-Inducible Factor 1, alpha Subunit/genetics*
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Endothelium, Vascular/metabolism*
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Molecular Docking Simulation
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Protein Interaction Maps/drug effects*
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Humans
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Sepsis/complications*
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Oxidative Stress/drug effects*
6.Huotan Jiedu Tongluo Decoction inhibits ferroptosis by regulating Nrf2/GPX4 pathway to ameliorate atherosclerotic lesions in ApoE~(-/-) mice.
Di GAO ; Teng-Hui TIAN ; Ke-Ying YU ; Xiao SHAO ; Wen XUE ; Zhi-Xuan ZHAO ; Yue DENG
China Journal of Chinese Materia Medica 2025;50(7):1908-1919
The purpose of this study was to clarify the effect of Huotan Jiedu Tongluo Decoction on atherosclerosis(AS) injury in ApoE~(-/-) mice by regulating the ferroptosis pathway. Seventy-five ApoE~(-/-) mice were randomly divided into model group, low-, medium-, and high-dose of Huotan Jiedu Tongluo Decoction groups, and evolocumab group(n=15), and 15 C57BL/6J mice were selected as the blank group. Mice in the blank group were fed with a normal diet, and those in the other groups were fed with a high-fat diet to induce AS. From the 9th week, mice in Huotan Jiedu Tongluo Decoction groups were administrated with Huotan Jiedu Tongluo Decoction at corresponding doses by gavage, and those in the blank group and the model group were given an equal volume of distilled water. Mice in the evolocumab group were treated with evolocumab 18.2 mg·kg~(-1 )by subcutaneous injection every 2 weeks. After 8 weeks of continuous intervention, oil red O staining and hematoxylin-eosin(HE) staining were employed to observe the lipid deposition and plaque formation in the aortic root. Masson staining was used to evaluate the collagen content in the aortic root. The serum levels of total cholesterol(TC), triglycerides(TG), high-density lipoprotein cholesterol(HDL-C), and low-density lipoprotein cholesterol(LDL-C) were determined by biochemical kits. The levels of Fe~(2+), superoxide dismutase(SOD), malondialdehyde(MDA), and glutathione(GSH) in the aorta were measured by colorimetry. The protein and mRNA levels of nuclear factor erythroid 2-related factor 2(Nrf2), glutathione peroxidase 4(GPX4), solute carrier family 7 member 11(SLC7A11), and acyl-CoA synthetase long chain family member 4(ACSL4) in the aorta were detected by Western blot and RT-qPCR, respectively. The expression of Nrf2, GPX4, and SLC7A11 was localized by immunofluorescence. The results showed that low-, medium-, and high-dose Huotan Jiedu Tongluo Decoction reduced the plaque formation of aortic root and increased the collagen content in AS mice. At the same time, Huotan Jiedu Tongluo Decoction improved the lipid metabolism by lowering the levels of TC, LDL-C, and TG and elevating the level of HDL-C in the serum. Huotan Jiedu Tongluo Decoction enhanced the antioxidant capacity by elevating the levels of GSH and SOD and lowering the level of MDA in the aorta and inhibiting the accumulation of Fe~(2+) in the aorta. In addition, Huotan Jiedu Tongluo Decoction up-regulated the protein and mRNA levels of Nrf2, GPX4, and SLC7A11, while down-regulating the protein and mRNA levels of ACSL4. In summary, Huotan Jiedu Tongluo Decoction can effectively alleviate AS lesions in ApoE~(-/-) mice by activating the Nrf2/GPX4 pathway, reducing lipid peroxidation, and inhibiting ferroptosis.
Animals
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Ferroptosis/drug effects*
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Atherosclerosis/metabolism*
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Drugs, Chinese Herbal/administration & dosage*
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NF-E2-Related Factor 2/genetics*
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Mice
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Mice, Inbred C57BL
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Apolipoproteins E/metabolism*
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Male
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Phospholipid Hydroperoxide Glutathione Peroxidase/genetics*
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Signal Transduction/drug effects*
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Humans
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Mice, Knockout
7.Repair of knee joint cartilage defects in rabbits using Gd-HA composite with adipose-derived mesenchymal stem cells
Ying BAO ; Wei-Li KONG ; Yu YANG ; Fu-Guo SHEN ; Shuai ZHANG ; Wen-Cai SUN
Acta Anatomica Sinica 2025;56(3):342-350
Objective To investigate the effect of Gd-hydroxyapatite(Gd-HA)stents with adipose mesenchymal cells(ADSCs)on the repair of knee articular cartilage defects.Methods To isolate,culture,and identify rabbit ADSCs by establishing a rabbit knee joint full-thickness cartilage defect model,a total of 18 rabbits were randomly divided into blank control group,Gd-HA scaffold group,and ADSCs+Gd-HA scaffold group.At week 12 and 24 after surgery,International Curtilage Repair Society(ICRS)score,HE,toluidine blue,modified red O bright green and ColⅡ were detected by immunohistochemical staining,then ColⅡand GAG mRNA expression levels were detected by O'Driscoll and Real-time PCR.ColⅡ protein expression was detected by Western blotting,GAG content was detected by DMMB,biomechanical strength was detected by indentation test,and PKH26 labeled ADSCs was used to trace the tissue engineering scaffold with Gd-HA composite ADSCs to evaluate the repair effect of rabbit knee cartilage defects.Results The ADSCs isolated and cultured in vitro showed good growth,stable phenotype and good directional differentiation through macroscopic observation and histological staining,it could be seen that the repair degree and effect of the knee joint full-thickness cartilage defect model implanted with Gd-HA scaffold group were better than those of the blank control group,while the cartilage repair situation of the ADSCs+Gd-HA scaffold group was better than that of the Gd-HA scaffold group(P<0.05);The ICRS and improved O'Driscoll scores were higher than the other two groups(P<0.05).Compared with the Gd-HA group,the ADSCs+Gd-HA group could produce ColⅡ and GAG during the process of cartilage repair,with stronger mechanical strength of the repaired tissue(P<0.05);PKH26 labeled ADSCs were found in the repaired tissues of the ADSCs+Gd-HA group,and they were involved in the composition of newly formed tissues.Conclusion Gd-HA scaffold material combined with ADSCs has a good repair effect on full-thickness cartilage defects in the knee joint as a new type of biological material for repairing joint cartilage defects.
8.Effects of high-fructose diet on hippocampal neurometabolites and anxiety and depression-like behaviors in mice
Shan-Shan ZHANG ; Ying LIU ; Yu-Wen ZHANG ; He WANG ; Wen-Sheng LI ; Qiong LIU
Acta Anatomica Sinica 2025;56(4):381-388
Objective To investigate the effects of short-term and long-term high-fructose diets on hippocampal neurometabolites and anxiety and depression-like behaviors in mice,revealing the potential mechanisms of high-fructose diets in mood disorders and providing a experimental basis for the prevention and treatment of related diseases.Methods C57BL/6J male mice were randomly divided into two groups,control group(standard diet,n=10)and experimental group(high-fructose diet,n=10).Four weeks(short-term)and eight weeks(long-term)later,each group of mice was examined for body weight and fasting blood glucose,and neurometabolites levels in the hippocampus were detected by hydrogen proton magnetic resonance spectroscopy(1H-MRS),followed by the open-field test,the forced-swimming test,and the tail-suspension test to evaluate anxiety-like and depression-like behaviors.Results High fructose diet for 4 weeks elevated glutamate levels and reduced glutathione and myo-inositol levels in mice,accompanied by shortened immobility time in the forced swim test.High fructose diet for 8 weeks not only led to abnormalities in body weight and glucose metabolism but also caused a reversal decrease in hippocampal glutamate levels and induced significant anxiety-like behaviors,and the decrease in hippocampal glutamate levels showed a significant negative correlation with the enhancement of anxiety-like behaviors.Conclusion Altered hippocampal glutamate levels may be a key contributing factor to the anxiety-like behaviors induced by long-term high-fructose diet.
9.COCKROACH SURVEILLANCE IN LANZHOU FROM 2016 TO 2023
Ying ZHANG ; Jing ZUO ; Qing-Ming SHI ; Zi-Peng LI ; Wen-Juan BA ; Zhi-Qing LI ; Ai-Miao LIAO ; Jing-Jing YU ; Guo-Jing BAO ; Xing LI ; Jun GAN ; Xiao-Lei YE
Acta Parasitologica et Medica Entomologica Sinica 2025;32(2):119-122
Objective To investigate the population composition,seasonal dynamics,and infestation levels of cockroaches in Lanzhou,China,and to provide information for the scientific development of cockroach control strategies.Methods Monitoring was conducted at three locations using the sticky trap method.Habitats included farm product markets,catering establishments,hotels,hospitals,and residential areas.Results From 2016 to 2023,the average cockroach density was 0.77 insects per board,with an average infestation rate of 10.84%.Blattella germanica was the dominant species.Seasonal density of cockroaches showed an approximately unimodal distribution,peaking in September.The highest average density and infestation rates were observed in farm product markets.Conclusions Cockroach density and infestation levels in Lanzhou remained relatively low.A comprehensive prevention and control strategy focusing on environmental management in key areas should be implemented according to the seasonal fluctuations.
10.The Mesencephalic Locomotor Region for Locomotion Control
Xing-Chen GUO ; Yan XIE ; Xin-Shuo WEI ; Wen-Fen LI ; Ying-Yu SUN
Progress in Biochemistry and Biophysics 2025;52(7):1804-1816
Locomotion, a fundamental motor function encompassing various forms such as swimming, walking, running, and flying, is essential for animal survival and adaptation. The mesencephalic locomotor region (MLR), located at the midbrain-hindbrain junction, is a conserved brain area critical for controlling locomotion. This review highlights recent advances in understanding the MLR’s structure and function across species, from lampreys to mammals and birds, with a particular focus on insights gained from optogenetic studies in mammals. The goal is to uncover universal strategies for MLR-mediated locomotor control. Electrical stimulation of the MLR in species such as lampreys, salamanders, cats, and mice initiates locomotion and modulates speed and patterns. For example, in lampreys, MLR stimulation induces swimming, with increased intensity or frequency enhancing propulsive force. Similarly, in salamanders, graded stimulation transitions locomotor outputs from walking to swimming. Histochemical studies reveal that effective MLR stimulation sites colocalize with cholinergic neurons, suggesting a conserved neurochemical basis for locomotion control. In mammals, the MLR comprises two key nuclei: the cuneiform nucleus (CnF) and the pedunculopontine nucleus (PPN). Both nuclei contain glutamatergic and GABAergic neurons, with the PPN additionally housing cholinergic neurons. Optogenetic studies in mice by selectively activating glutamatergic neurons have demonstrated that the CnF and PPN play distinct roles in motor control: the CnF drives rapid escape behaviors, while the PPN regulates slower, exploratory movements. This functional specialization within the MLR allows animals to adapt their locomotion patterns and speed in response to environmental demands and behavioral objectives. Similar to findings in lampreys, the CnF and PPN in mice transmit motor commands to spinal effector circuits by modulating the activity of brainstem reticular formation neurons. However, they achieve this through distinct reticulospinal pathways, enabling the generation of specific behaviors. Further insights from monosynaptic rabies viral tracing reveal that the CnF and PPN integrate inputs from diverse brain regions to produce context-appropriate behaviors. For instance, glutamatergic neurons in the PPN receive signals from other midbrain structures, the basal ganglia, and medullary nuclei, whereas glutamatergic neurons in the CnF rarely receive inputs from the basal ganglia but instead are strongly influenced by the periaqueductal grey and inferior colliculus within the midbrain. These differential connectivity patterns underscore the specialized roles of the CnF and PPN in motor control, highlighting their unique contributions to coordinating locomotion. Birds exhibit exceptional flight capabilities, yet the avian MLR remains poorly understood. Comparative studies suggest that the pedunculopontine tegmental nucleus (PPTg) in birds is homologous to the mammalian PPN, which contains cholinergic neurons, while the intercollicular nucleus (ICo) or nucleus isthmi pars magnocellularis (ImC) may correspond to the CnF. These findings provide important clues for identifying the avian MLR and elucidating its role in flight control. However, functional validation through targeted experiments is urgently needed to confirm these hypotheses. Optogenetics and other advanced techniques in mice have greatly advanced MLR research, enabling precise manipulation of specific neuronal populations. Future studies should extend these methods to other species, particularly birds, to explore unique locomotor adaptations. Comparative analyses of MLR structure and function across species will deepen our understanding of the conserved and evolved features of motor control, revealing fundamental principles of locomotion regulation throughout evolution. By integrating findings from diverse species, we can uncover how the MLR has been adapted to meet the locomotor demands of different environments, from aquatic to aerial habitats.

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