1.Research progress on the molecular genetic mechanism of Parkinson's disease.
Chinese Journal of Medical Genetics 2026;43(2):151-157
The pathogenesis of Parkinson's disease is closely related to genetic factors. This article has systematically reviewed the research progress of molecular genetic mechanism on Parkinson's disease by focusing on the role of six high-penetrance pathogenic genes (SNCA, LRRK2, PRKN, PINK1, PARK7, and VPS35) and some risk genes (such as GBA1). These genetic variants eventually converge in three core pathogenic biological pathways, including lysosomal-autophagy pathway disorder, mitochondrial quality control disorder and α-synuclein metabolic abnormality. In-depth understanding of these molecular mechanisms is of great significance for the development of targeted therapy and realization of precision medicine for this disease.
Humans
;
Parkinson Disease/metabolism*
;
alpha-Synuclein/genetics*
;
Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/genetics*
;
Genetic Predisposition to Disease
;
Protein Kinases/genetics*
;
Animals
;
Glucosylceramidase/genetics*
;
Ubiquitin-Protein Ligases/genetics*
2.Vitexin-4 ″-O-glucoside alleviates acetaminophen-induced acute liver injury.
Fan DONG ; Shanglei LAI ; Jiannan QIU ; Xiaobing DOU
Journal of Zhejiang University. Medical sciences 2025;54(3):307-317
OBJECTIVES:
To explore the protective effect of vitexin-4 ″-O-glucoside (VOG) against acetaminophen-induced acute liver injury in mice and its underlying mechanism.
METHODS:
C57BL/6 mice were randomly divided into 4 groups: normal control group, model control group, low-dose group of VOG (30 mg/kg), and high-dose group of VOG (60 mg/kg). Acute liver injury was induced by intraperitoneal injection of acetaminophen (500 mg/kg). VOG was administrated by gavage 2 h before acetaminophen treatment in VOG groups. The protective effect of VOG against acute liver injury was evaluated by detecting alanine transaminase (ALT), aspartate transaminase (AST) levels and hematoxylin and eosin staining. The malondialdehyde (MDA) content, superoxide dismutase (SOD) and catalase (CAT) activity in liver were detected to evaluate the hepatic oxidative stress. The expression levels of tumor necrosis factor (TNF)-α, Il-1β, and Il-6 in liver were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The expression levels of phosphorylated c-jun N-terminal kinase (JNK)/JNK, phosphorylated p38/p38, inositol-requiring enzyme 1 alpha (IRE-1α), X-box binding protein 1s (XBP1s), and glucose-regulated protein 78 (GRP78) in liver were detected by Western blotting. An endoplasmic reticulum stress model was established in AML-12 cells using tunicamycin. Cell viability was assessed using the CCK-8 assay, and the degree of cell damage was detected by lactate dehydrogenase (LDH) assay. The gene expression levels of Ire-1α, Xbp1s, and Grp78 in the cells were detected using qRT-PCR.
RESULTS:
In the animal experiments, compared with the model control group, VOG significantly improved plasma ALT and AST levels, liver MDA content, as well as SOD and CAT activities. VOG also reduced the expression levels of Tnf-α, Il-1β, and Il-6 in the liver, and improved protein phosphorylation levels of JNK and p38, as well as the protein expression levels of IRE-1α, XBP1s, and GRP78. In cell experiments, VOG pretreatment enhanced cell viability, reduced LDH release and decreased the mRNA expression of Ire-1α, Xbp1s, and Grp78.
CONCLUSIONS
VOG can suppress inflammation and oxidative stress, and alleviate acetaminophen-induced acute liver injury in mice by suppressing endoplasmic reticulum stress and modulating the MAPK signaling pathway.
Animals
;
Endoplasmic Reticulum Chaperone BiP
;
Mice
;
Acetaminophen/adverse effects*
;
Mice, Inbred C57BL
;
Chemical and Drug Induced Liver Injury/prevention & control*
;
Glucosides/therapeutic use*
;
Oxidative Stress/drug effects*
;
Male
;
Apigenin/therapeutic use*
;
Liver/drug effects*
;
Tumor Necrosis Factor-alpha/metabolism*
;
Endoplasmic Reticulum Stress/drug effects*
;
X-Box Binding Protein 1
;
Endoribonucleases/metabolism*
;
Interleukin-1beta/metabolism*
;
Interleukin-6/metabolism*
;
Protein Serine-Threonine Kinases
3.Molecular Mechanism of Thymoquinone Inhibition on Malignant Proliferation of Acute Myeloid Leukemia Cells.
Jie LIN ; Fan-Lin ZENG ; Yan-Quan LIU ; Zhi-Min YAN ; Zuo-Tao LI ; Qing-Lin XU ; Hong-Quan ZHU
Journal of Experimental Hematology 2025;33(2):311-318
OBJECTIVE:
To investigate the effects of thymoquinone on the proliferation of acute myeloid leukemia (AML) cells and its molecular mechanism, so as to provide theoretical basis for the basic research on the anti-leukemia of traditional Chinese medicine.
METHODS:
The HL-60 and THP-1 cells were treated with thymoquinone at different concentration gradients, cell proliferation was detected by CCK-8 method, morphological changes were detected by Wright-Giemsa method, apoptosis was detected by Annexin V/PI double staining flow cytometry, and apoptosis and signal pathway protein expression were detected by Western blot. Real-time quantitative fluorescence PCR and Western blot were used to detect the expression changes of high mobility family members of SRY-related proteins (SOX).
RESULTS:
Thymoquinone inhibited the malignant proliferation of HL-60 and THP-1 cells, up-regulated the expression of pro-apoptotic protein Bax, down-regulated the expression of anti-apoptotic protein Bcl-2 and Survivin, and hydrolyzed Caspase-3 to induce the apoptosis of HL-60 and THP-1 cells. Thymoquinone could also significantly down-regulate the phosphorylation of PI3K, Akt and mTOR, and inhibit the malignant biological characteristics of HL-60 and THP-1 cells by inhibiting the activation of PI3K/Akt/mTOR pathway. After thymoquinone intervention in HL-60 and THP-1 cells, the expression of SOX2 and SOX4 could be down-regulated significantly. At low concentration ( < 10 μmol/L), the expression of SOX12 was weakly affected by thymoquinone. With increasing concentration, the expression of SOX12 could be down-regulated, however, thymoquinone had no effect on SOX11 expression.
CONCLUSION
Thymoquinone can inhibit the proliferation of AML cells, and its mechanism may be related to inhibiting the activation of PI3K/Akt/mTOR signaling pathway, regulating the expression of apoptotic proteins and core members of SOX family.
Humans
;
Benzoquinones/pharmacology*
;
Cell Proliferation/drug effects*
;
Leukemia, Myeloid, Acute/metabolism*
;
Apoptosis/drug effects*
;
HL-60 Cells
;
Signal Transduction/drug effects*
;
Proto-Oncogene Proteins c-akt/metabolism*
;
TOR Serine-Threonine Kinases/metabolism*
;
Proto-Oncogene Proteins c-bcl-2/metabolism*
;
bcl-2-Associated X Protein/metabolism*
;
Cell Line, Tumor
;
Phosphatidylinositol 3-Kinases/metabolism*
;
THP-1 Cells
4.Mechanism of DYRK1A in Cytarabine Resistance in Acute Myeloid Leukemia.
Journal of Experimental Hematology 2025;33(3):648-652
OBJECTIVE:
To investigate the role of DYRK1A in the cytarabine (Ara-C) resistance mechanism of acute myeloid leukemia (AML) cells.
METHODS:
Overexpression and silencing of DYRK1A gene in THP-1 cells were used to observe whether the sensitivity of THP-1 cells to Ara-C was altered. RT-PCR was used to detect the changes in mRNA expression of related genes during Ara-C transport or metabolism. Western blot and RT-PCR were used to detect SAMHD1 expression after regulating DYRK1A expression in Ara-C treated cells. Co-IP technology was used to detect the interaction between Cyclin L2, DYRK1A, and SAMHD1.
RESULTS:
Overexpression of DYRK1A decreased Ara-C sensitivity in THP-1 cells while silencing DYRK1A increased it. Overexpression and silencing of DYRK1A did not affect Ara-C transport or metabolic gene expression. Overexpression of DYRK1A could increase the expression of SAMHD1 protein in cells, while silencing DYRK1A reduced SAMHD1 expression. Cyclin L2 interacted with DYRK1A and SAMHD1 in THP-1 cells.
CONCLUSION
DYRK1A is involved in Ara-C resistance in AML cells, and its mechanism may be related to increased expression of SAMHD1 by interacting with Cyclin L2.
Humans
;
Cytarabine/pharmacology*
;
Protein-Tyrosine Kinases/metabolism*
;
Leukemia, Myeloid, Acute
;
Dyrk Kinases
;
Drug Resistance, Neoplasm
;
Protein Serine-Threonine Kinases/metabolism*
;
SAM Domain and HD Domain-Containing Protein 1
;
Cell Line, Tumor
5.Effect of Juglone on Proliferation Inhibition and RIPK1/RIPK3/MLKL Expression in Acute Myeloid Leukemia Cells.
Chun-Yi LYU ; Xue-Wei YIN ; Zong-Hong LI ; Chen HAN ; Yan WANG ; Zhen-Zhen WANG ; Lyu-Ye LIU ; Rui-Rong XU
Journal of Experimental Hematology 2025;33(4):980-985
OBJECTIVE:
To study the effects and mechanisms of juglone on the proliferation and apoptosis of acute myeloid leukemia (AML) cells.
METHODS:
Juglone and AML targets were collected from public databases, and the intersecting target clusters were taken for functional enrichment analysis to explore the potential mechanism of juglone in the treatment of AML. Then wet experiments were performed to verify. AML cell lines including KG-1a, MV-411, THP-1 and MOLM-13 were treated with different concentrations of juglone for 24 h. MTT assay was used to detect cell viability and determine the IC50, and the most sensitive cell line was screened for subsequent experiments. Flow cytometry was used to detect the apoptosis of cells treated with different concentrations of juglone. Western blot was performed to check the expression of relevant proteins.
RESULTS:
Eleven targets were obtained as potential targets for juglone in the treatment of AML, and the top ten significantly enriched pathways were intrinsic pathway of apoptosis, programmed cell death, cytochrome c-mediated apoptotic response, apoptosis, apoptotic factor-mediated response, regulated necrosis, cytokine signaling in immune system, signaling by interleukins, oncogene induced senescence, and signal transduction. The cell viability of KG-1a, MV-411, THP-1 and MOLM-13 was decreased with increasing juglone concentration after 24 h of juglone treatment (r =-0.992, -0.886, -0.956, -0.910). Among them, MOLM-13 was the most sensitive to juglone. The results of flow cytometry showed that the apoptosis rate of MOLM-13 tended to significantly increase with the increasing concentration of juglone (r =0.99). At the same time point, p-RIPK1/RIPK1, p-RIPK3/RIPK3, and p-MLKL/MLK were decreased in each juglone concentration group compared with control group.
CONCLUSION
Juglone inhibits the viability of KG-1a, MV-411, THP-1 and MOLM-13 cells, and induces apoptosis of MOLM-13 cells, the mechanism of which may be related to the inhibition of RIPK1/RIPK3/MLKL signaling pathway.
Humans
;
Naphthoquinones/pharmacology*
;
Apoptosis/drug effects*
;
Cell Proliferation/drug effects*
;
Leukemia, Myeloid, Acute/pathology*
;
Cell Line, Tumor
;
Receptor-Interacting Protein Serine-Threonine Kinases/metabolism*
;
Protein Kinases/metabolism*
;
Signal Transduction
;
Cell Survival/drug effects*
6.Mechanism of Regulating MK2 to Improve Bone Marrow Inflammatory Damage after Hematopoietic Stem Cell Transplantation.
Zhao-Hui WANG ; Bo LONG ; Yu-Han WANG ; Zhi-Ting LIU ; Zi-Jie XU ; Shuang DING
Journal of Experimental Hematology 2025;33(5):1453-1460
OBJECTIVE:
To investigate the role of MK2 inhibitor MMI-0100 on inflammatory response after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and related mechanisms.
METHODS:
An allo-HSCT mouse model was established. Recipient rats were randomly divided into BMT+NaCl group and BMT+MMI-0100 group, and were injected with NaCl and MMI-0100 every day after transplantation, respectively. Samples of the two groups were collected on d 7 and 14, femur paraffin sections were stained with HE, and pathological changes in the bone marrow cavity were observed under the light microscope. The gene and protein expression levels of pro-inflammatory cytokines IL-1β and IL-18 were detected by qPCR and Western blot. Macrophage typing was detected by flow cytometry. The expression levels of NLRP3 and Caspase-1 were detected by Western blot.
RESULTS:
Inflammatory cell infiltration in the bone marrow cavity was significantly reduced in the BMT+MMI-0100 group. Western blot results showed that the protein expression levels of IL-1β and IL-18 in the BMT+MMI-0100 group were decreased compared to the BMT+NaCl group on day 7 and day 14 (all P <0.01). The qPCR results showed that compared to the BMT+NaCl group, the IL-18 gene expression levels in the BMT+MMI-0100 group were significantly reduced on day 7 and day 14 (both P <0.01). In the BMT+MMI-0100 group, the expression level of IL-1β gene decreased on day 7 (P <0.05), but increased and was higher than that in the BMT+NaCl group on day 14 (P <0.05). Flow cytometry results showed that the expression of M1 macrophages and M1/M2 ratio decreased in the BMT+MMI-0100 group compared to BMT+NaCl group (all P <0.05). Western blot results showed that the protein expression levels of NLRP3 and Caspase-1 in the BMT+MMI-0100 group were lower than those in the BMT+NaCl group (all P <0.05).
CONCLUSION
MMI-0100 can ameliorate bone marrow inflammatory injury after allo-HSCT and may act by reducing NLRP3 expression to promote M2 polarization.
Animals
;
Interleukin-1beta/metabolism*
;
Rats
;
Interleukin-18/metabolism*
;
Hematopoietic Stem Cell Transplantation/adverse effects*
;
Mice
;
NLR Family, Pyrin Domain-Containing 3 Protein/metabolism*
;
Inflammation
;
Bone Marrow/pathology*
;
Protein Serine-Threonine Kinases/metabolism*
;
Intracellular Signaling Peptides and Proteins/antagonists & inhibitors*
;
Caspase 1/metabolism*
;
Macrophages
;
Transplantation, Homologous
7.Effect of Huayu Tongluo moxibustion on learning-memory ability in rats with vascular dementia based on hippocampal Mst1/NF-κB p65 pathway.
Ping WANG ; Jun YANG ; Yu KONG ; Yating ZHANG ; Yinqiu FAN ; Haiping SHI ; Lanying LIU
Chinese Acupuncture & Moxibustion 2025;45(1):53-60
OBJECTIVE:
To observe the effects of Huayu Tongluo (transforming stasis and unblocking collaterals) moxibustion on learning-memory ability and hippocampal mammalian sterile 20-like kinase 1 (Mst1)/nuclear factor κB (NF-κB) p65 pathway related to inflammatory response in rats with vascular dementia (VD).
METHODS:
A total of 60 male Wistar rats of SPF grade were randomly divided into a sham operation group (12 rats) and a modeling group (48 rats). VD model was established by the method of modified bilateral common carotid artery permanent ligation in the modeling group. Thirty-six rats with successful modeling were randomly divided into a model group, a moxibustion group and a western medication group, with 12 rats in each group. Huayu Tongluo moxibustion was applied at "Dazhui" (GV14), "Baihui" (GV20) and "Shenting" (GV24) in the moxibustion group, 20 min each time, once a day, 7 day-intervention was as one course, and 1 day-interval was taken between two courses, for a total of 3 courses. In the western medication group, piracetam was given 0.72 mg/kg by intragastric administration, twice a day, the course of intervention was same as that of the moxibustion group. The learning-memory ability was detected by Morris water maze test; the morphology of hippocampal CA1 region was observed by HE staining; the mRNA expression of Mst1, M1 microglia markers CD86, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) was detected by real-time PCR; the levels of IL-6 and TNF-α in hippocampus were detected by ELISA; and the protein expression of Mst1 and NF-κB p65 in hippocampus was detected by Western blot in rats of each group.
RESULTS:
Compared with the sham operation group, the escape latency was prolonged in the model group (P<0.05); compared with the model group, the escape latency was shortened in the moxibustion group and the western medication group (P<0.05). The cells in the CA1 region of hippocampus were disordered, cell collapse and irregular nuclei could be observed in the model group; compared with the model group, the cell arrangement in the CA1 region of hippocampus was more regular, and the damage was improved in the moxibustion group and the western medication group. Compared with the sham operation group, the mRNA expression of Mst1, CD86, IL-6 and TNF-α, as well as the protein expression of Mst1, NF-κB p65 in hippocampus were increased in the model group (P<0.05). Compared with the model group, the mRNA expression of Mst1, CD86, IL-6 and TNF-α, as well as the protein expression of Mst1, NF-κB p65 in hippocampus were decreased in the moxibustion group and the western medication group (P<0.05). Compared with the sham operation group, the levels of IL-6 and TNF-α in hippocampus were increased in the model group (P<0.05). Compared with the model group, the levels of IL-6 and TNF-α in hippocampus were decreased in the moxibustion group and the western medication group (P<0.05).
CONCLUSION
Huayu Tongluo moxibustion can improve the learning-memory ability of VD rats, the mechanism may be related to regulating the activation of microglia through Mst1/NF-κB p65 pathway, reducing the release of pro-inflammatory factors i.e. IL-6 and TNF-α, so as to alleviating the damage of inflammatory factors in the hippocampus of VD rats.
Animals
;
Male
;
Rats
;
Moxibustion
;
Hippocampus/metabolism*
;
Rats, Wistar
;
Dementia, Vascular/genetics*
;
Memory/drug effects*
;
Humans
;
Transcription Factor RelA/genetics*
;
Learning
;
Protein Serine-Threonine Kinases/genetics*
;
Acupuncture Points
;
Interleukin-6/genetics*
;
Signal Transduction/drug effects*
;
Drugs, Chinese Herbal
8.Artificial intelligence-enabled discovery of a RIPK3 inhibitor with neuroprotective effects in an acute glaucoma mouse model.
Xing TU ; Zixing ZOU ; Jiahui LI ; Simiao ZENG ; Zhengchao LUO ; Gen LI ; Yuanxu GAO ; Kang ZHANG
Chinese Medical Journal 2025;138(2):172-184
BACKGROUND:
Retinal ganglion cell (RGC) death caused by acute ocular hypertension is an important characteristic of acute glaucoma. Receptor-interacting protein kinase 3 (RIPK3) that mediates necroptosis is a potential therapeutic target for RGC death. However, the current understanding of the targeting agents and mechanisms of RIPK3 in the treatment of glaucoma remains limited. Notably, artificial intelligence (AI) technologies have significantly advanced drug discovery. This study aimed to discover RIPK3 inhibitor with AI assistance.
METHODS:
An acute ocular hypertension model was used to simulate pathological ocular hypertension in vivo . We employed a series of AI methods, including large language and graph neural network models, to identify the target compounds of RIPK3. Subsequently, these target candidates were validated using molecular simulations (molecular docking, absorption, distribution, metabolism, excretion, and toxicity [ADMET] prediction, and molecular dynamics simulations) and biological experiments (Western blotting and fluorescence staining) in vitro and in vivo .
RESULTS:
AI-driven drug screening techniques have the potential to greatly accelerate drug development. A compound called HG9-91-01, identified using AI methods, exerted neuroprotective effects in acute glaucoma. Our research indicates that all five candidates recommended by AI were able to protect the morphological integrity of RGC cells when exposed to hypoxia and glucose deficiency, and HG9-91-01 showed a higher cell survival rate compared to the other candidates. Furthermore, HG9-91-01 was found to protect the retinal structure and reduce the loss of retinal layers in an acute glaucoma model. It was also observed that the neuroprotective effects of HG9-91-01 were highly correlated with the inhibition of PANoptosis (apoptosis, pyroptosis, and necroptosis). Finally, we found that HG9-91-01 can regulate key proteins related to PANoptosis, indicating that this compound exerts neuroprotective effects in the retina by inhibiting the expression of proteins related to apoptosis, pyroptosis, and necroptosis.
CONCLUSION
AI-enabled drug discovery revealed that HG9-91-01 could serve as a potential treatment for acute glaucoma.
Animals
;
Glaucoma/metabolism*
;
Neuroprotective Agents/pharmacology*
;
Mice
;
Receptor-Interacting Protein Serine-Threonine Kinases/metabolism*
;
Artificial Intelligence
;
Retinal Ganglion Cells/metabolism*
;
Disease Models, Animal
;
Molecular Docking Simulation
;
Mice, Inbred C57BL
;
Male
9.Disulfiram alleviates cardiac hypertrophic injury by inhibiting TAK1-mediated PANoptosis.
Wei-Dong LI ; Xuan-Yang SHEN ; Xiao-Lu JIANG ; Hong-Fu WEN ; Yuan SHEN ; Mei-Qi ZHANG ; Wen-Tao TAN
Acta Physiologica Sinica 2025;77(2):222-230
The study aims to examine the effects and potential mechanisms of disulfiram (DSF) on cardiac hypertrophic injury, focusing on the role of transforming growth factor-β-activated kinase 1 (TAK1)-mediated pan-apoptosis (PANoptosis). H9C2 cardiomyocytes were treated with angiotensin II (Ang II, 1 µmol/L) to establish an in vitro model of myocardial hypertrophy. DSF (40 µmol/L) was used to treat cardiomyocyte hypertrophic injury models, either along or in combination with the TAK1 inhibitor, 5z-7-oxozeaenol (5z-7, 0.1 µmol/L). We assessed cell damage using propidium iodide (PI) staining, measured cell viability with CCK8 assay, quantified inflammatory factor levels in cell culture media via ELISA, detected TAK1 and RIPK1 binding rates using immunoprecipitation, and analyzed the protein expression levels of key proteins in the TAK1-mediated PANoptosis pathway using Western blot. In addition, the surface area of cardiomyocytes was measured with Phalloidin staining. The results showed that Ang II significantly reduced the cellular viability of H9C2 cardiomyocytes and the binding rate of TAK1 and RIPK1, significantly increased the surface area of H9C2 cardiomyocytes, PI staining positive rate, levels of inflammatory factors [interleukin-1β (IL-1β), IL-18, and tumor necrosis factor α (TNF-α)] in cell culture media and p-TAK1/TAK1 ratio, and significantly up-regulated key proteins in the PANoptosis pathway [pyroptosis-related proteins NLRP3, Caspase-1 (p20), and GSDMD-N (p30), apoptosis-related proteins Caspase-3 (p17), Caspase-7 (p20), and Caspase-8 (p18), as well as necroptosis-related proteins p-MLKL, RIPK1, and RIPK3]. DSF significantly reversed the above changes induced by Ang II. Both 5z-7 and exogenous IL-1β weakened these cardioprotective effects of DSF. These results suggest that DSF may alleviate cardiac hypertrophic injury by inhibiting TAK1-mediated PANoptosis.
Animals
;
MAP Kinase Kinase Kinases/physiology*
;
Rats
;
Myocytes, Cardiac/pathology*
;
Disulfiram/pharmacology*
;
Cardiomegaly
;
Apoptosis/drug effects*
;
Cell Line
;
Angiotensin II
;
Necroptosis/drug effects*
;
Interleukin-1beta/metabolism*
;
Receptor-Interacting Protein Serine-Threonine Kinases/metabolism*
;
Lactones
;
Resorcinols
;
Zearalenone/administration & dosage*
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
;
Rats, Sprague-Dawley
;
Physical Conditioning, Animal/physiology*
;
Rats
;
Muscle, Skeletal/metabolism*
;
TOR Serine-Threonine Kinases/metabolism*
;
Male
;
Hypertrophy
;
Adaptation, Physiological/physiology*
;
Adaptor Proteins, Signal Transducing/metabolism*
;
Ribosomal Protein S6 Kinases, 70-kDa/metabolism*
;
Intracellular Signaling Peptides and Proteins

Result Analysis
Print
Save
E-mail