AIM:To investigate the effect of intrinsic specific transforming growth factor-β(TGF-β)signaling on regeneration and repair of myofibers in acute skeletal myositismice model induced by cardiotoxin(CTX).METHODS:One hundred and eighty-six wild C57BL/6 mice and one hundred and thirty-eight mice with conditional knockout of TGF-β receptor 2(TGF-βr2)in myofibers(SM TGF-βr2-/-mice)were selected.CTX injection to anterior tibial muscle(TA)in-duced acute myoinjury in mice.Some SM TGF-βr2-/-mice were given Smad signaling agonist SRI-011381(SRI)intramus-cular injection.All mice were mainly divided into the following groups:control group,SM TGF-βr2-/-group and SM TGF-βr2-/-+SRI group.Twenty-four mice were selected in each group.RT-qPCR and immunofluorescence staining were used to detect the relative mRNA level,protein expression of inflammatory cytokines and low-density lipoprotein receptor-related protein 1(LRP1),respectively,while the relative protein expression of myosin heavy chain 3(MHY3)and embryonic myosine heavy chain(eMHC)in damaged muscle was detected by Western blot and immunofluorescence staining.In vi-tro,after being extracted from neonatal mice,myogenic precursor cells(MPCs)were cultured in an pro-inflammatory mi-lieu and treated with SRI,recombinant mouse extracellular matrix protein 1(rmECM1)alone or in combination.Hereby,they were divided into the following seven groups:control-MPCs group,control-MPCs+LPS group,TGF-βr2-/--MPCs group,TGF-βr2-/--MPCs+LPS group,TGF-βr2-/--MPCs+LPS+SRI group,TGF-βr2-/--MPCs+LPS+rmECM1 group,and TGF-βr2-/--MPCs+LPS+SRI+rmECM1 group.Six mice were selected in each group.RT-qPCR and Western blot were used to detect the relative mRNA level,protein expression of major histocompatibility complex class I molecules(MHC-I/H-2Kb),major histocompatibility complex class II molecules(MHC-II/H2-Eα),Toll-like receptor 3(TLR3),and LRP1.And the relative protein expression of MoyD and myogenin in myotubes was detected by immunofluorescence staining.RE-SULTS:In vivo,compared with control group,SM TGF-βr2-/-group showed the significant upregulation of pro-inflamma-tory cytokines(P<0.05),and the opposite trend of anti-inflammatory cytokines,LRP1,MHY3,eMHC in the injured muscle(P<0.05),with delayed regeneration and repair of myofibers.In vitro,compared with control-MPCs+LPS group,LRP1,MoyD and myogenin significantly downregulated in TGF-βr2-/--MPCs+LPS group,but the downregulation trend was corrected after giving SRI treatment(P<0.05).In addition,compared with the TGF-βr2-/--MPCs+LPS group,the combi-nation of rmECM1 and SRI significantly upregulated the protein expression of MyoD and myogenin(P<0.05).CONCLU-SION:In a mouse model of acute skeletal myositis,intrinsic TGF-β signaling specifically in myofibers regulates local im-mune behavior.It promotes the expression of LRP1 in damaged muscle via Smad2/3 signaling,and LRP1 can then fully bind to ECM1,thereby facilitating muscle regeneration and repair,and improving the prognosis of acute skeletal myositis.

Aim To investigate the role of corylin in angiotensin Ⅱ(Ang Ⅱ)-induced cardiomyocyte hy-pertrophy and its underlying mechanisms.Methods An Ang Ⅱ-induced cardiomyocyte hypertrophy model was established and treated with corylin.Real-time PCR was employed to assess hypertrophic gene mRNA expression,and immunofluorescence was used to meas-ure cardiomyocyte surface area.Western blot and en-zyme activity assay kits were used to evaluate SIRT1 expression and activity.Results Corylin markedly mitigated Ang Ⅱ-induced hypertrophic gene expression and cardiomyocyte surface area enlargement.Moreo-ver,it prevented the Ang Ⅱ-mediated decline in SIRT1 protein levels and deacetylase activity.Further investi-gation indicated that corylin inhibited Ang Ⅱ-driven NF-κB transcriptional activity and the expression of its downstream target genes,such as TNF-α,IL-6,and IL-1β.Notably,SIRT1 silencing abolished the protective effects of corylin against cardiomyocyte hypertrophy,as well as its regulation of the SIRT1/NF-κB signaling pathway.Conclusion Corylin suppresses cardiomyo-cyte hypertrophy by modulating the SIRT1-dependent NF-κB signaling pathway.

This paper aimed to explore the effects of Duzhong Decoction(DZD)-containing serum on the proliferation and osteoblast differentiation of MC3T3-E1 cells through L-type voltage-gated calcium channels(L-VGCCs). L-VGCCs inhibitors, nifedipine and verapamil, were used to block L-VGCCs in osteoblasts. MC3T3-E1 cells were divided into a control group, a low-dose DZD-containing serum(L-DZD) group, a medium-dose DZD-containing serum(M-DZD) group, a high-dose DZD-containing serum(H-DZD) group, a nifedipine group, a H-DZD + nifedipine group, verapamil group, and a H-DZD + verapamil group. The CCK-8 method was used for cell proliferation analysis, alkaline phosphatase(ALP) assay kits for intracellular ALP activity measurement, Western blot for protein expression level in cells, real-time fluorescence quantitative PCR technology for intracellular mRNA expression level determination, fluorescence spectrophotometer for free Ca~(2+) concentration determination in osteoblasts, and alizarin red staining(ARS) for mineralized nodule formation in osteoblasts. The experimental results show that compared to the control group, DZD groups can promote MC3T3-E1 cell proliferation, ALP activity, and mineralized nodule formation, increase intracellular Ca~(2+) concentrations, and upregulate the protein expression of bone morphogenetic protein 2(BMP2), collagen Ⅰ(COL1), α2 subunit protein of L-VGCCs(L-VGCCα2), and the mRNA expression of Runt-related transcription factor 2(RUNX2), and BMP2. After blocking L-VGCCs with nifedipine and verapamil, the intervention effects of DZD-containing serum were inhibited to varying degrees. Both nifedipine and verapamil could inhibit ALP activity, reduce mineralized nodule areas, and downregulate the expression of bone formation-related proteins. Moreover, the effects of DZD-containing serum on increasing MC3T3-E1 cell proliferation, osteoblast differentiation, and Ca~(2+) concentrations, upregulating the mRNA expression of osteoprotegerin(OPG) and protein expression of phosphorylated protein kinase B(p-Akt) and phosphorylated forkhead box protein O1(p-FOXO1), and upregulating phosphatase and tensin homolog(PTEN) expression were reversed by nifedipine. The results indicate that DZD-containing serum can increase the Ca~(2+) concentration in MC3T3-E1 cells to promote bone formation, which may be mediated by L-VGCCs and the PTEN/Akt/FoxO1 signaling pathway, providing a new perspective on the mechanism of DZD in treating osteoporosis.
Animals ; Osteoblasts/metabolism* ; Cell Proliferation/drug effects* ; Cell Differentiation/drug effects* ; Mice ; Drugs, Chinese Herbal/pharmacology* ; Calcium Channels, L-Type/genetics* ; Alkaline Phosphatase/genetics* ; Serum/chemistry* ; Cell Line ; Osteogenesis/drug effects* ; Bone Morphogenetic Protein 2/genetics*

AIM:To investigate the effect of intrinsic specific transforming growth factor-β(TGF-β)signaling on regeneration and repair of myofibers in acute skeletal myositismice model induced by cardiotoxin(CTX).METHODS:One hundred and eighty-six wild C57BL/6 mice and one hundred and thirty-eight mice with conditional knockout of TGF-β receptor 2(TGF-βr2)in myofibers(SM TGF-βr2-/-mice)were selected.CTX injection to anterior tibial muscle(TA)in-duced acute myoinjury in mice.Some SM TGF-βr2-/-mice were given Smad signaling agonist SRI-011381(SRI)intramus-cular injection.All mice were mainly divided into the following groups:control group,SM TGF-βr2-/-group and SM TGF-βr2-/-+SRI group.Twenty-four mice were selected in each group.RT-qPCR and immunofluorescence staining were used to detect the relative mRNA level,protein expression of inflammatory cytokines and low-density lipoprotein receptor-related protein 1(LRP1),respectively,while the relative protein expression of myosin heavy chain 3(MHY3)and embryonic myosine heavy chain(eMHC)in damaged muscle was detected by Western blot and immunofluorescence staining.In vi-tro,after being extracted from neonatal mice,myogenic precursor cells(MPCs)were cultured in an pro-inflammatory mi-lieu and treated with SRI,recombinant mouse extracellular matrix protein 1(rmECM1)alone or in combination.Hereby,they were divided into the following seven groups:control-MPCs group,control-MPCs+LPS group,TGF-βr2-/--MPCs group,TGF-βr2-/--MPCs+LPS group,TGF-βr2-/--MPCs+LPS+SRI group,TGF-βr2-/--MPCs+LPS+rmECM1 group,and TGF-βr2-/--MPCs+LPS+SRI+rmECM1 group.Six mice were selected in each group.RT-qPCR and Western blot were used to detect the relative mRNA level,protein expression of major histocompatibility complex class I molecules(MHC-I/H-2Kb),major histocompatibility complex class II molecules(MHC-II/H2-Eα),Toll-like receptor 3(TLR3),and LRP1.And the relative protein expression of MoyD and myogenin in myotubes was detected by immunofluorescence staining.RE-SULTS:In vivo,compared with control group,SM TGF-βr2-/-group showed the significant upregulation of pro-inflamma-tory cytokines(P<0.05),and the opposite trend of anti-inflammatory cytokines,LRP1,MHY3,eMHC in the injured muscle(P<0.05),with delayed regeneration and repair of myofibers.In vitro,compared with control-MPCs+LPS group,LRP1,MoyD and myogenin significantly downregulated in TGF-βr2-/--MPCs+LPS group,but the downregulation trend was corrected after giving SRI treatment(P<0.05).In addition,compared with the TGF-βr2-/--MPCs+LPS group,the combi-nation of rmECM1 and SRI significantly upregulated the protein expression of MyoD and myogenin(P<0.05).CONCLU-SION:In a mouse model of acute skeletal myositis,intrinsic TGF-β signaling specifically in myofibers regulates local im-mune behavior.It promotes the expression of LRP1 in damaged muscle via Smad2/3 signaling,and LRP1 can then fully bind to ECM1,thereby facilitating muscle regeneration and repair,and improving the prognosis of acute skeletal myositis.

Aim To investigate the role of corylin in angiotensin Ⅱ(Ang Ⅱ)-induced cardiomyocyte hy-pertrophy and its underlying mechanisms.Methods An Ang Ⅱ-induced cardiomyocyte hypertrophy model was established and treated with corylin.Real-time PCR was employed to assess hypertrophic gene mRNA expression,and immunofluorescence was used to meas-ure cardiomyocyte surface area.Western blot and en-zyme activity assay kits were used to evaluate SIRT1 expression and activity.Results Corylin markedly mitigated Ang Ⅱ-induced hypertrophic gene expression and cardiomyocyte surface area enlargement.Moreo-ver,it prevented the Ang Ⅱ-mediated decline in SIRT1 protein levels and deacetylase activity.Further investi-gation indicated that corylin inhibited Ang Ⅱ-driven NF-κB transcriptional activity and the expression of its downstream target genes,such as TNF-α,IL-6,and IL-1β.Notably,SIRT1 silencing abolished the protective effects of corylin against cardiomyocyte hypertrophy,as well as its regulation of the SIRT1/NF-κB signaling pathway.Conclusion Corylin suppresses cardiomyo-cyte hypertrophy by modulating the SIRT1-dependent NF-κB signaling pathway.

Objective To investigate the effect of E2 signaling in myofibers on muscular macrophage efferocytosis in mice with cardiotoxin-induced acute skeletal muscle injury.Methods Female wild-type C57BL/6 mice with and without ovariectomy and male C57BL/6 mice were given a CTX injection into the anterior tibial muscle to induce acute muscle injury,followed by intramuscular injection of β-estradiol(E2)or 4-hydroxytamoxifen(4-OHT).The changes in serum E2 of the mice were detected using ELISA,and the number,phenotypes,and efferocytosis of the macrophages in the inflammatory exudates and myofiber regeneration and repair were evaluated using immunofluorescence staining and flow cytometry.C2C12 cells were induced to differentiate into mature myotubes,which were treated with IFN-γ for 24 before treatment with β-Estradiol or 4-OHT.The treated myotubes were co-cultured with mouse peritoneal macrophages in a 1:2 ratio,followed by addition of PKH67-labeled apoptotic mouse mononuclear spleen cells induced by UV irradiation,and macrophage efferocytosis was observed using immunofluorescence staining and flow cytometry.Results Compared with the control mice,the female mice with ovariectomy showed significantly increased mononuclear macrophages in the inflammatory exudates,with increased M1 cell percentage,reduced M2 cell percentage and macrophage efferocytosis in the injured muscle,and obviously delayed myofiber regeneration and repair.In the cell co-culture systems,treatment of the myotubes with β-estradiol significantly increased the number and proportion of M2 macrophages and macrophage efferocytosis,while 4-OHT treatment resulted in the opposite changes.Conclusion In injured mouse skeletal muscles,myofiber E2 signaling promotes M1 to M2 transition to increase macrophage efferocytosis,thereby relieving inflammation and promoting muscle regeneration and repair.

Objective To investigate the effect of E2 signaling in myofibers on muscular macrophage efferocytosis in mice with cardiotoxin-induced acute skeletal muscle injury.Methods Female wild-type C57BL/6 mice with and without ovariectomy and male C57BL/6 mice were given a CTX injection into the anterior tibial muscle to induce acute muscle injury,followed by intramuscular injection of β-estradiol(E2)or 4-hydroxytamoxifen(4-OHT).The changes in serum E2 of the mice were detected using ELISA,and the number,phenotypes,and efferocytosis of the macrophages in the inflammatory exudates and myofiber regeneration and repair were evaluated using immunofluorescence staining and flow cytometry.C2C12 cells were induced to differentiate into mature myotubes,which were treated with IFN-γ for 24 before treatment with β-Estradiol or 4-OHT.The treated myotubes were co-cultured with mouse peritoneal macrophages in a 1:2 ratio,followed by addition of PKH67-labeled apoptotic mouse mononuclear spleen cells induced by UV irradiation,and macrophage efferocytosis was observed using immunofluorescence staining and flow cytometry.Results Compared with the control mice,the female mice with ovariectomy showed significantly increased mononuclear macrophages in the inflammatory exudates,with increased M1 cell percentage,reduced M2 cell percentage and macrophage efferocytosis in the injured muscle,and obviously delayed myofiber regeneration and repair.In the cell co-culture systems,treatment of the myotubes with β-estradiol significantly increased the number and proportion of M2 macrophages and macrophage efferocytosis,while 4-OHT treatment resulted in the opposite changes.Conclusion In injured mouse skeletal muscles,myofiber E2 signaling promotes M1 to M2 transition to increase macrophage efferocytosis,thereby relieving inflammation and promoting muscle regeneration and repair.

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that regulates gene expression in a range of cells, including immune and epithelial cells. AhR signaling plays important roles in the immune system in both health and disease states. Tapinarof is a first-in-class small-molecule topical therapeutic AhR modulating agent launched for the treatment of psoriasis. To improve the activity and chemical stability of Tapinarof, a series of 2-phenylchromen-4-one derivatives were designed, synthesized and evaluated as novel AhR agonists. Compounds 5a, 5c, 5e and 5f potently activated AhR with an EC₅₀ value of 7, 9, 6 and 6 nmol·L^-1, respectively, which are 10-14 fold more potent than Tapinarof. Compounds 5a and 5e exhibit comparable inhibitory effects on IFN-γ production as Tapinarof. Furthermore, compounds 5a-5f exhibited favorable photochemical stability compared to Tapinarof. The compounds may eventually serve as lead compounds for the development of new AhR agonists.

Objective:To investigate the effects of human umbilical cord mesenchymal stem cells exosomes (hucMSC-Exo) on depression-like behavior and polarization dynamic transition of hippocampal microglia in chronic unpredictable mild stress(CUMS) mice.Methods:The hucMSC was isolated, cultured, and the 5th generation hucMSC-Exo was extracted by ultracentrifugation and identified.Biological markers of CD9 and CD63 of hucMSC-Exo were detected by Western blot.A total of 12 SPF grade male C57BL/6J mice were randomly selected to establish depression model by CUMS method at the same time, and relevant behavioral experiments, including opening field test (OFT) and forced swimming test (FST) were used to detect changes of depression-like behavior in CUMS mice. After modeling, 12 mice were randomly divided into two groups, with 6 mice in each group. One group of mice was the exosome treatment group (CUMS+ Exo group) after stereotactic brain injection of hucMSC-Exo in the hippocampus, and the other group was the CUMS group. The expression of inflammatory signals in the hippocampus of mice in both groups were detected by micro PET/CT scanning technique. The proportion of M2-type microglia and M1-type microglia in the hippocampus of mice was detected by tissue immunofluorescence. β3-tubulin immunofluorescence staining was used to detect the length changes of neuronal axons in the depressed cell model constructed with corticosterone (CORT). EdU staining was used to detect neuronal proliferation. TUNEL staining was used to observe the apoptosis of neurons in the hippocampus of mice.Statistical analysis was conducted by GraphPad 8.0 software, and t-test was used for inter group comparison. Results:Under the electron microscope, hucMSC-Exo showed typical " double-layer cup-like" small vesicle-like changes and the particle diameter was about 100 nm.Western blot confirmed the expression of lconic proteins of CD9 and CD63. In the micro PET/CT scans, the uptake of [18F]DPA-714 in the CUMS+ Exo group was lower than that of the CUMS group, and the difference was statistically significant ((0.91±0.02)g/mL, (0.81±0.05)g/mL, t=4.54, P=0.001 1). In the opening field test, the percentage of central path length ((3.40±0.44)%, (5.17±0.90)%, t=4.33, P=0.001 5) and the time spent on the central path ((7.04±0.60)s, (10.22±1.41)s, t=6.02, P=0.000 1) in CUMS+ Exo group were higher than those in CUMS group, while the total distances of the two groups were not statistically significant ( t=0.48, P>0.05). In the forced swimming test, the immobility time in the CUMS+ Exo group was less than that in the CUMS group ((152.33±7.28) s, (133.50±4.32) s, t=5.45, P=0.000 3). In tissue immunofluorescence experiments, compared with the CUMS group, the proportion of M2-type microglia of hippocampus in the CUMS+ Exo group((0.33±0.04), (0.59±0.12), t=5.11, P=0.000 5)increased and the proportion of M1-type microglia ((0.56±0.06), (0.41±0.03), t=5.15, P=0.000 4) decreased in the CUMS+ Exo group. β3-tubulin-labeled immunofluorescence results showed an increase of neuronal axon length in the CORT+ Exo group compared with that in the CORT group((3.99±0.99) μm, (6.76±1.11) μm, t=6.10, P=0.000 1). The results of cell proliferation test showed an increase of proliferation rate in the CORT+ Exo group compared with that in the CORT group((0.74±0.07), (0.64±0.03), t=3.32, P=0.001 8). In the TUNEL staining experiment, the apoptosis rate of neurons in the hippocampal region of mice in the CUMS+ Exo group was lower than that of CUMS group ((0.24±0.04), (0.39±0.04), t=6.11, P=0.000 1). Conclusion:hucMSC-Exo can promote the conversion of M1 polarized microglia to M2 type microglia to alleviate depression-like behavior and reduce neuronal apoptosis in CUMS mice.

Objective:To investigate the predictive value of different body obesity measures for non-alcoholic fatty liver disease (NAFLD).Methods:It was a cross-sectional study. The present study was a case-control study involving 553 subjects who underwent physical examination from January to April 2022. The subjects were divided into NAFLD group ( n=321 cases) and control group ( n=232 cases) according to abdominal ultrasound imaging parameters. All subjects completed a general information questionnaire, liver ultrasound examination, serum biochemical indices and physical measurements. Logistic regression model was used to analyze the correlation between human obesity measures (neck circumference, triceps skinfold thickness (TSF),body mass index (BMI), waist-to-hip ratio, lipid accumulation index (LAP), visceral fat index (VAI), body roundness index (BRI) and a body shape index (ABSI)) and NAFLD. Receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to evaluate the predictive value of single and combined measures of obesity for NAFLD. Results:The subjects were stratified by gender, and the quartile levels of BMI, neck circumference, TSF, waist-to-hip ratio, LAP, VAI and BRI were all correlated with NAFLD in both male and female (all P<0.05). After further adjustment for confounding factors, compared with those in group Q 1, group Q 4 of the above-mentioned indexes still had higher odds ratios ( P<0.05). The AUC value of LAP in predicting NAFLD was the largest in both men and women, which was 0.836(0.788-0.876) and 0.885(0.839-0.921), and the cut-off value was 41.93 and 33.27, respectively. There was no significant difference in AUC of ROC predicting NAFLD among LAP, BRI and BMI ( P>0.05). The AUC of ABSI in predicting NAFLD was less than 0.7(namely 0.584(0.525-0.641) and 0.679(0.618-0.735) in men and women, respectively), which indicated poor predictive performance for NAFLD. In the pairwise combination index, the AUC of ROC predicting NAFLD with TSF+LAP in male was the largest, which was 0.864(0.819-0.901), and there was statistical significance when compared with BRI (AUC=0.818(0.769-0.860)) and BMI (AUC=0.816(0.767-0.858)) ( P<0.05), but there was no statistical significance when compared with LAP (AUC=0.836(0.788-0.876)) ( P>0.05). The AUC of ROC predicting NAFLD with VAI+LAP in women was the largest, it was 0.894(0.849-0.928), there was statistical significance when compared with BMI (AUC=0.849(0.799-0.890)) ( P<0.05), but there was no statistical significance when compared with LAP (AUC=0.885(0.839-0.921)) and BRI (AUC=0.870(0.822-0.908)) ( P>0.05). Conclusion:BMI, neck circumference, TSF, waist-to-hip ratio, LAP, VAI and BRI all have good predictive value for NAFLD.