1.The Regulatory Effects and Mechanisms of Piezo1 Channel on Chondrocytes and Bone Metabolic Dysregulation in Osteoarthritis
Yan LI ; Tao LIU ; Yu-Biao GU ; Hui-Qing TIAN ; Lei ZHANG ; Bi-Hui BAI ; Zhi-Jun HE ; Wen CHEN ; Jin-Peng LI ; Fei LI
Progress in Biochemistry and Biophysics 2026;53(3):564-576
Osteoarthritis (OA), a highly prevalent degenerative joint disease worldwide, is defined by articular cartilage degradation, abnormal bone remodeling, and persistent chronic inflammation. It severely compromises patients’ quality of life, and currently, there is no radical cure. Abnormal mechanical stress is widely regarded as a core driver of OA pathogenesis, and the exploration of mechanical signal perception and transduction mechanisms has become crucial for deciphering OA’s pathophysiological processes. Piezo1, a key mechanosensitive cation channel belonging to the Piezo protein family, has recently gained significant attention due to its pivotal role in mediating cellular responses to mechanical stimuli in joint tissues. This review systematically examines Piezo1’s expression patterns, regulatory mechanisms, and pathological functions in OA, with a particular focus on its dual roles in modulating chondrocyte homeostasis and bone metabolism disorders, while also delving into the underlying molecular signaling pathways and potential therapeutic implications. Piezo1, consisting of approximately 2 500 amino acids and forming a unique trimeric propeller-like structure, is widely expressed in chondrocytes, osteocytes, mesenchymal stem cells, and synovial cells. It exhibits permeability to cations such as Ca2+, K+, and Na+, and directly responds to membrane tension changes induced by mechanical stimuli like fluid shear stress and mechanical overload. In OA patients and animal models, Piezo1 expression is significantly upregulated, especially in cartilage regions subjected to abnormal mechanical stress (e.g., human temporomandibular joint cartilage). This overexpression is closely associated with aggravated cartilage degeneration, increased chondrocyte apoptosis, accelerated cellular senescence, and intensified inflammatory responses. Mechanical overload and pro-inflammatory cytokines (e.g., IL-1β) are key inducers of Piezo1 upregulation: IL-1β activates the PI3K/AKT/mTOR signaling pathway to enhance Piezo1 expression, forming a pathogenic positive feedback loop that inhibits chondrocyte autophagy, promotes apoptosis, and further accelerates joint degeneration. Mechanistically, Piezo1 mediates OA progression through multiple interconnected pathways. When activated by mechanical stress, Piezo1 triggers excessive Ca2+ influx, leading to endoplasmic reticulum stress (ERS) and mitochondrial dysfunction, which directly induce chondrocyte apoptosis. This process involves the activation of downstream signaling cascades such as cGAS-STING and YAP-MMP13/ADAMTS5. YAP, a transcriptional regulator, upregulates the expression of matrix metalloproteinase 13 (MMP13) and aggrecanase (ADAMTS5), thereby accelerating cartilage matrix degradation. Additionally, Piezo1-driven Ca2+ overload promotes the accumulation of reactive oxygen species (ROS) and upregulates senescence markers (p16 and p21), accelerating chondrocyte senescence via the p38MAPK and NF-κB pathways. Senescent chondrocytes secrete senescence-associated secretory phenotype (SASP) factors (e.g., IL-6, IL-1β), further amplifying joint inflammation. In terms of bone metabolism, Piezo1 maintains joint homeostasis by promoting the differentiation of fibrocartilage stem cells into chondrocytes and balancing bone formation and resorption through regulating the FoxC1/YAP axis and RANKL/OPG ratio. Therapeutically, targeting Piezo1 shows promising potential. Preclinical studies have demonstrated that Piezo1 inhibitors (e.g., GsMTx4) can reduce joint damage and alleviate pain in OA mice. Simultaneously, siRNA-mediated co-silencing of Piezo1 and TRPV4 (another mechanosensitive channel) decreases intracellular Ca2+ concentration, inhibits chondrocyte apoptosis, and promotes cartilage repair. Conditional knockout of Piezo1 using Gdf5-Cre transgenic mice alleviates cartilage degeneration in post-traumatic OA models by downregulating MMP13 and ADAMTS5 expression. Despite existing challenges, such as off-target effects of inhibitors, inefficient local drug delivery, and interindividual genetic variability, strategies like developing selective Piezo1 antagonists, optimizing targeted nanocarriers, and combining Piezo1-targeted therapy with physical therapy provide viable avenues for clinical translation. The authors propose that Piezo1 serves as a critical therapeutic target for OA, and future research should focus on deciphering its context-dependent regulatory networks, developing tissue-specific intervention strategies, and validating their efficacy and safety in clinical trials to address the unmet medical needs of OA patients.
2.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.
3.The first record of Anopheles messeae (Diptera: Culicidae) parasitized by water mites in China
Xue-ru CHEN ; Wen-zhen YAO ; Yu-hao LI ; Gui-chang LI ; Tao MENG ; Qun-ling FENG ; Xin-hui LIU ; Li-hong QIAO ; Xiang-ting WU ; Xue-feng ZHANG ; Cheng-lin LI ; Xue-cheng DONG ; Da-wei WANG ; Xiao-yan SI ; Yu-hong GUO
Acta Parasitologica et Medica Entomologica Sinica 2026;33(1):53-57
Objective This study reports on the obligatory parasitism of water mites Arrenurus sp. on Anopheles messeae at the Manzhouli Port, Inner Mongolia, China. Methods Duing July 2024, a survey on the mosquito diversity was conducted at the Manzhouli Port. Captured mosquitoes and their ectoparasites were identified to species level. Results A total of 1840 adult mosquitoes were collected, representing species from three genera: Culex(Cx. modestus, Cx. pipiens pallens), Aedes(Ae. dorsalis, Ae. flavidorsalis, Ae. flavescens), and Anopheles (An. messeae). Among all the mosqutioes specimens,3 out of 150 captured An. messeae were found to carry ectoparasitic mites, with number of 2,4,27 mites separately. Morphological and molecular identification reached the same result as water mites(Hydrachnidiae, Hydracrina). COI gene sequence showed 94% similarity with the closest species Arrenurus truncatellus. Conlusions Literature review suggests water mites are host-specific parasitism of mosquito species and herein with the first record of Arrenurus sp. parasiting on An. Messeae in the most high-latitude region globally.
4.Acute Inflammatory Pain Induces Sex-different Brain Alpha Activity in Anesthetized Rats Through Optically Pumped Magnetometer Magnetoencephalography
Meng-Meng MIAO ; Yu-Xuan REN ; Wen-Wei WU ; Yu ZHANG ; Chen PAN ; Xiang-Hong LIN ; Hui-Dan LIN ; Xiao-Wei CHEN
Progress in Biochemistry and Biophysics 2025;52(1):244-257
ObjectiveMagnetoencephalography (MEG), a non-invasive neuroimaging technique, meticulously captures the magnetic fields emanating from brain electrical activity. Compared with MEG based on superconducting quantum interference devices (SQUID), MEG based on optically pump magnetometer (OPM) has the advantages of higher sensitivity, better spatial resolution and lower cost. However, most of the current studies are clinical studies, and there is a lack of animal studies on MEG based on OPM technology. Pain, a multifaceted sensory and emotional phenomenon, induces intricate alterations in brain activity, exhibiting notable sex differences. Despite clinical revelations of pain-related neuronal activity through MEG, specific properties remain elusive, and comprehensive laboratory studies on pain-associated brain activity alterations are lacking. The aim of this study was to investigate the effects of inflammatory pain (induced by Complete Freund’s Adjuvant (CFA)) on brain activity in a rat model using the MEG technique, to analysis changes in brain activity during pain perception, and to explore sex differences in pain-related MEG signaling. MethodsThis study utilized adult male and female Sprague-Dawley rats. Inflammatory pain was induced via intraplantar injection of CFA (100 μl, 50% in saline) in the left hind paw, with control groups receiving saline. Pain behavior was assessed using von Frey filaments at baseline and 1 h post-injection. For MEG recording, anesthetized rats had an OPM positioned on their head within a magnetic shield, undergoing two 15-minute sessions: a 5-minute baseline followed by a 10-minute mechanical stimulation phase. Data analysis included artifact removal and time-frequency analysis of spontaneous brain activity using accumulated spectrograms, generating spectrograms focused on the 4-30 Hz frequency range. ResultsMEG recordings in anesthetized rats during resting states and hind paw mechanical stimulation were compared, before and after saline/CFA injections. Mechanical stimulation elevated alpha activity in both male and female rats pre- and post-saline/CFA injections. Saline/CFA injections augmented average power in both sexes compared to pre-injection states. Remarkably, female rats exhibited higher average spectral power 1 h after CFA injection than after saline injection during resting states. Furthermore, despite comparable pain thresholds measured by classical pain behavioral tests post-CFA treatment, female rats displayed higher average power than males in the resting state after CFA injection. ConclusionThese results imply an enhanced perception of inflammatory pain in female rats compared to their male counterparts. Our study exhibits sex differences in alpha activities following CFA injection, highlighting heightened brain alpha activity in female rats during acute inflammatory pain in the resting state. Our study provides a method for OPM-based MEG recordings to be used to study brain activity in anaesthetized animals. In addition, the findings of this study contribute to a deeper understanding of pain-related neural activity and pain sex differences.
5.Association between neutrophil-to-lymphocyte ratio and in-hospital mortality risk in patients with acute aortic dissection:a multicenter 10-year retrospective cohort study
Zi-Xuan LIU ; Hui-Qing WANG ; Xiao-Dan ZHONG ; Xing-Wei HE ; Wen-Hua WANG ; Dan YU ; Bao-Quan ZHANG ; Chun-Wen LI ; He-Song ZENG
Medical Journal of Chinese People's Liberation Army 2025;50(8):917-924
Objective To investigate the role of the neutrophil-to-lymphocyte ratio(NLR)in predicting the in-hospital mortality risk of patients with acute aortic dissection(AAD)in multicenter hospitals.Methods A multicenter retrospective cohort study was conducted.Clinical data were collected from 2642 AAD patients who were hospitalized in five teaching hospitals:Tongji Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology,Henan Provincial People's Hospital,Fuwai Central China Cardiovascular Hospital,the Third Affiliated Hospital of Xinxiang Medical University,and the Second Affiliated Hospital of Chongqing Medical University between August 2010 and December 2021.According to the quartiles of serum NLRlevels,the patients were divided into four groups:first quartile(Q1,n=660),second quartile(Q2,n=661),third quartile(Q3,n=661),and fourth quartile(Q4,n=660).The clinical characteristics and biochemical indicators of each group were compared.Partial correlation analysis was used to assess the relationship between NLR and cardiovascular parameters.Restricted cubic splines,Kaplan-Meier survival analysis,and Cox regression models were employed to evaluate the association between NLR levels and in-hospital mortality risk in AAD patients.Results The median age of all patients was 54[interquartile range(IQR):46-63]years,including 2096 males and 546 females.Compared with Q1-Q3 groups,patients inQ4group had a lower incidence of smoking history and diabetes history,and were more likely to have DeBakey type Ⅰ AAD(P<0.05).Additionally,the levels of aspartate aminotransferase,high-density lipoprotein cholesterol,creatinine,and D-dimer in Q4 group were higher,while the levels of triglycerides and C-reactive protein(CRP)were lower(P<0.01).The results of partial correlation analysis showed that the plasma NLR level was positively correlated with D-dimer(r=0.43,P<0.01)and creatinine(r=0.16,P<0.01).The restricted cubic spline function in the Cox model revealed a significant non-linear relationship between the plasma NLR level and clinical outcomes in AAD patients(P<0.01).Kaplan-Meier survival analysis indicated that patients in Q4 group had the highest in-hospital mortality rate compared with Q1-Q3 groups(P<0.0001).Furthermore,multivariate Cox regression analysis demonstrated that compared with Q1 group,the hazard ratio(HR)of NLR in Q4 group was 1.77(95%CI 1.33-2.37,P<0.001),which was an independent risk factor for the primary endpoint events.Conclusion A higher plasma NLR level is significantly associated with the occurrence of cardiovascular events in AAD patients,and this association remains significant even after adjusting for potential confounding factors such as the multicenter visiting hospitals.
6.Clinical characteristics of 10 cases of immune checkpoint inhibitor-related diabetes mellitus and literature review
Wen-Wen GONG ; Shu LI ; Yu-Long CHEN ; Li ZANG ; Jin DU ; Xian-Ling WANG ; Zhao-Hui LYU ; Qing-Hua GUO
Medical Journal of Chinese People's Liberation Army 2025;50(9):1103-1109
Objective To analyze the clinical characteristics,treatment,and prognosis of immune checkpoint inhibitor-related diabetes mellitus(ICI-DM).Methods The clinical characteristics,laboratory examinations,treatment regimens,and follow-up outcomes of 10 ICI-DM patients who were diagnosed and treated in the First Medical Center of Chinese PLA General Hospital between July 2019 and December 2024 were retrospectively analyzed.Relevant literatures were retrieved from domestic and foreign databases such as PubMed,CNKI,and VIP.The clinical characteristics of ICI-DM were summarized based on the literature results.Results All 10 patients were PD-1 inhibitor users,including 5 males and 5 females,with a median age of 54.5(51.3,64.0)years and a body mass index(BMI)of(22.0±2.15)kg/m2.Among them,9 cases(90.0%)were fulminant type 1 diabetes mellitus(FT1DM);9 cases(90.0%)had a severity of adverse events reaching grade 3-4 according to the Common Terminology Criteria for adverse events(CTCAE).The median time from PD-1 inhibitor treatment to the occurrence of the classic diabetes symptoms referred to as"three more and one less"(polyuria,polydipsia,polyphagia,and weight loss)in all patients was 145.5(110.5,204.8)days,and the medication duration was 6.0(4.3,7.8)cycles.The average blood glucose level of the 10 patients at the time of consultation was 25.3(10.0-41.4)mmol/L,and the glycated hemoglobin(HbA1c)level was 8.0%(6.6%-10.9%).Eight patients had fasting and 2-hour C-peptide levels<0.1 ng/ml(fasting C-peptide from<0.010 to 0.067 ng/ml,2-hour C-peptide from<0.010 to 0.077 ng/ml).Nine of the 10 patients were negative for diabetes autoantibodies,while 1 was not tested.All 10 patients were successfully treated with insulin and other therapies.During the follow-up after discharge,all patients still relied on insulin treatment,and no significant recovery of pancreatic islet β cell function was observed compared with that at discharge.Literature review revealed that ICI-DM was more common in PD-1 inhibitor users,with clinical mainly manifested as diabetic ketoacidosis(DKA)(65.4%)and diabetic ketosis(13.1%).Patients had severely impaired pancreatic islet function and required long-term insulin treatment,and some cases were complicated by thyroid or pituitary dysfunction.Conclusions ICI-DM typically presents as FT1DM,often manifesting with DKA or diabetic ketosis at onset.It is characterized by severe and irreversible loss of pancreatic islet function,necessitating lifelong insulin therapy.To enable early detection and prompt treatment,close monitoring of blood glucose is essential during ICI treatment.
7.Research progress on activation and blocking of cholinergic anti-inflammatory pathway
Yu-Qi LIU ; Yu-Ru WANG ; Wen-Yue JIA ; Yu-Meng ZHANG ; Yang LIU ; Hui-Qin HAO
Medical Journal of Chinese People's Liberation Army 2025;50(11):1469-1477
The cholinergic anti-inflammatory pathway(CAP)is a neuroimmunoregulatory pathway that has attracted much attention in recent years.This pathway releases acetylcholine(ACh)by activating the vagus nerve.The binding of ACh to α7 nicotinic acetylcholine receptor receptors on the surface of macrophages can inhibit the release of proinflammatory factors,so as to effectively regulate the inflammatory response in the body.CAP plays a key role in suppressing excessive inflammatory responses and maintaining immune balance,providing a potential therapeutic pathway for a variety of inflammatory immune diseases.Research progress on the physiological function of CAP and its activation and blocking methods are reviewed in this paper,in order to provide new methods and ideas for treatment of inflammation-related diseases and exploring therapeutic drugs targeting CAP pathway.
8.Curcumin improving behavioral deficits in Parkinson's disease mice via modulation of gut microbiota
Wen-Hui LI ; Zhi-Hong ZHAO ; Li-Juan WANG ; Jin-Jing HE ; Yu-Ting LIU ; Qiu-Qin HAN
Acta Anatomica Sinica 2025;56(2):143-149
Objective To explore the mechanism by which curcumin improves behavioral deficits in mice with Parkinson's disease(PD)through fecal microbiota transplantation.Methods A subacute model of PD in mice was induced by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP).Fecal microbiota from both the model group and the curcumin(Cur)-treated group(80 m g/kg)were collected and analyzed.The experiment involving fecal microbiota transplantation was structured into four distinct groups,fecal microbiota solvent transplantation group(FMTcon),model fecal microbiota transplantation group(FMTmodel),MPTP-induced model group(model),and model group subjected to fecal microbiota transplantation following curcumin treatment(model+FMTCur).The motor skills of the mice were assessed by using rod rotation,pole climbing experiment,and open field tests.Immunofluorescence techniques were employed to observe the expression tyrosine hydroxylase(TH)-positive neurons in the substantia nigra of the brain.Additionally,the gene expression of tumor necrosis factor-α(TNF-α)in the midbrain of mice was analyzed,alongside the protein expression of nuclear factor-κB(NF-κB)and nucleotide binding oligomerization domain-like receptor protein 3(NLRP3).Results The subacute PD animal model in mice was successfully established,and fecal microbiota were separated and gathered.The model group exhibited significant motor impairment,as evidenced by a shortened rod rotation time(P<0.05),prolonged pole climbing time(P<0.05),significantly reduced total movement distance within the open field(P<0.001),and decreased time spent in the central zone(P<0.01).The relative expression level of TH+neurons in the substantia nigra was significantly reduced(P<0.01).Moreover,mRNA expression of TNF-α in the midbrain increased significantly(P<0.01),along with significant elevations in protein expression of NF-κB(P<0.001),phosphorylated NF-κB(p-NF-κB)(P<0.01),NLRP3(P<0.001),and Caspase-1(P<0.01).The transplanted model microbial group(FMTmodel)also exhibited motor impairment,manifested by a trend of shortened rod rotation time,prolonged pole climbing time,a significant decrease in total movement distance within the open field(P<0.01),and a trend of shortened time spent in the central zone.The relative expression level of TH+neurons in the substantia nigra decreased significantly(P<0.05).Additionally,mRNA expression of TNF-α in the midbrain increased significantly(P<0.01),along with notable elevations in the protein expression of NF-κB(P<0.05),and Caspase-1(P<0.01).Treatment with curcumin in the fecal microbiota transplantation group of mice(model+FMTCur)showed improvements in motor abilities,evidenced by shortened pole climbing time(P<0.05),significantly prolonged rod rotation time(P<0.01),and extended time spent in the central zone(P<0.05).The relative expression level of TH+dopaminergic neurons in the substantia nigra increased significantly(P<0.05).Moreover,mRNA expression of TNF-α in the midbrain decreased significantly(P<0.01),along with notable reductions in the protein expression of NF-κB(P<0.001),p-NF-κB(P<0.01),NLRP3(P<0.05),and Caspase-1(P<0.01).Conclusion Fecal microbiota transplantation in PD model mice can induce behavioral deficits,damage TH+neurons in the substantia nigra,and trigger neuroinflammation in the brain.Subsequent curcumin treatment can ameliorate these deficits,reverse damage to TH+neurons,reduce neuroinflammatory factors,and decrease the expression of NF-κB and NLRP3 pathways.This preliminary evidence suggests that curcumin may improve Parkinsonian behavioral deficits in mice by modulating the gut microbiota.
9.Local overexpression of miR-429 sponge in subcutaneous white adipose tissue improves obesity and related metabolic disorders.
Liu YAO ; Wen-Jing XIU ; Chen-Ji YE ; Xin-Yu JIA ; Wen-Hui DONG ; Chun-Jiong WANG
Acta Physiologica Sinica 2025;77(3):441-448
Obesity is a worldwide health problem. An imbalance in energy metabolism is an important cause of obesity and related metabolic diseases. Our previous studies showed that inhibition of miR-429 increased the protein level of uncoupling protein 1 (UCP1) in beige adipocytes; however, whether local inhibition of miR-429 in subcutaneous adipose tissue affects diet-induced obesity and related metabolic disorders remains unclear. The aim of this study was to investigate the effect of local overexpression of miR-429 sponge in subcutaneous adipose tissue on obesity and related metabolic disorders. The control adeno-associated virus (AAV) or AAV expressing the miR-429 sponge was injected into mouse inguinal white adipose tissue. Seven days later, the mice were fed a high-fat diet for 10 weeks to induce obesity. The effects of the miR-429 sponge on body weight, adipose tissue weight, plasma glucose and lipid levels, and hepatic lipid content were explored. The results showed that the overexpression of miR-429 sponge in subcutaneous white adipose tissue reduced body weight and fat mass, decreased fasting blood glucose and plasma cholesterol levels, improved glucose tolerance, and alleviated hepatic lipid deposition in mice. Mechanistic investigation showed that the inhibition of miR-429 significantly upregulated the expression of UCP1 in adipocytes and adipose tissue. These results suggest that local inhibition of miR-429 in subcutaneous white adipose tissue ameliorates obesity and related metabolic disorders potentially by upregulating UCP1, and miR-429 is a potential therapeutic target for the treatment of obesity and related metabolic disorders.
Animals
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MicroRNAs/physiology*
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Obesity/metabolism*
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Mice
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Adipose Tissue, White/metabolism*
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Metabolic Diseases
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Subcutaneous Fat/metabolism*
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Male
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Uncoupling Protein 1/metabolism*
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Diet, High-Fat
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Mice, Inbred C57BL
10.Eccentric treadmill exercise promotes adaptive hypertrophy of gastrocnemius in rats.
Zhi-Qiang DAI ; Yu KE ; Yan ZHAO ; Ying YANG ; Hui-Wen WU ; Hua-Yu SHANG ; Zhi XIA
Acta Physiologica Sinica 2025;77(3):449-464
The present study aimed to investigate the effects of eccentric treadmill exercise on adaptive hypertrophy of skeletal muscle in rats. Thirty-two 3-month-old Sprague Dawley (SD) rats were selected and randomly assigned to one of the four groups based on their body weights: 2-week quiet control group (2C), 2-week downhill running exercise group (2E), 4-week quiet control group (4C), and 4-week downhill running exercise group (4E). The downhill running protocol for rats in the exercise groups involved slope of -16°, running speed of 16 m/min, training duration of 90 min, and 5 training sessions per week. Twenty-four hours after the final session of training, all the four groups of rats underwent an exhaustion treadmill exercise. After resting for 48 h, all the rats were euthanized and their gastrocnemius muscles were harvested for analysis. HE staining was used to measure the cross-sectional area (CSA) and diameter of muscle fibers. Transmission electron microscope was used to observe the ultrastructural changes in muscle fibers. Purithromycin surface labeling translation method was used to measure protein synthesis rate. Immunofluorescence double labeling was used to detect the colocalization levels of lysosomal-associated membrane protein 2 (Lamp2)-leucyl-tRNA synthetase (LARS) and Lamp2-mammalian target of rapamycin (mTOR). Western blot was used to measure the protein expression levels of myosin heavy chain (MHC) IIb and LARS, as well as the phosphorylation levels of mTOR, p70 ribosomal protein S6 kinase (p70S6K), and eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1). The results showed that, compared with the 2C group rats, the 2E group rats showed significant increases in wet weight of gastrocnemius muscle, wet weight/body weight ratio, running distance, running time, pre- and post-exercise blood lactate levels, myofibrillar protein content, colocalization levels of Lamp2-LARS and Lamp2-mTOR, and LARS protein expression. Besides these above changes, compared with the 4C group, the 4E group further exhibited significantly increased fiber CSA, fiber diameter, protein synthesis rate, and phosphorylation levels of mTOR, p70S6K, and 4E-BP1. Compared with the quiet control groups, the exercise groups exhibited ultrastructural damage of rat gastrocnemius muscle, which was more pronounced in the 4E group. These findings suggest that eccentric treadmill exercise may promote mTOR translocation to lysosomal membrane, activating mTOR signaling via up-regulating LARS expression. This, in turn, increases protein synthesis rate through the mTOR-p70S6K-4E-BP1 signaling pathway, promoting protein deposition and inducing adaptive skeletal muscle hypertrophy. Although the ultrastructural changes of skeletal muscle are more pronounced, the relatively long training cycles during short-term exercise periods have a more significant effect on promoting gastrocnemius muscle protein synthesis and adaptive hypertrophy.
Animals
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Rats, Sprague-Dawley
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Physical Conditioning, Animal/physiology*
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Rats
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Muscle, Skeletal/metabolism*
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TOR Serine-Threonine Kinases/metabolism*
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Male
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Hypertrophy
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Adaptation, Physiological/physiology*
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Adaptor Proteins, Signal Transducing/metabolism*
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Ribosomal Protein S6 Kinases, 70-kDa/metabolism*
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Intracellular Signaling Peptides and Proteins


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