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 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.

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.

Objective To establish ovarian cancer cell line SKVO3 that can stably express human ADP ribosylation factor-4 (ARF4). Methods A eukaryotic expression vector pCDH-CMV-MCS-EF1-Puro/ARF4 was constructed and transfected into SKOV3 cells after verifying by DNA sequencing. The expression of ARF4 mRNA was verified by real-time quantitative PCR (qRT-PCR). Then, the recombinant plasmid with lentiviral packaging plasmids were co-transfected into SKOV3 cells for packaging. The recombinant lentiviral particles LV-ARF4 were collected and transfected into SKOV3 cells, and the stable transfected SKOV3 cell line was screening by culture with puromycin. The expression of ARF4 gene was detected by qRT-PCR and Western Blot. Results A eukaryotic expression vector pCDH-CMV-MCS-EF1-Puro/ARF4 was successfully constructed. The vector could significantly up-regulate the expression of ARF4 mRNA in SKOV3 cells and be successfully packaged into recombinant lentiviral particles in HEK-293T cells. Compared with the control group, the relative expression level of ARF4 mRNA and protein in SKOV3 cells was significantly increased after the infection with LV-ARF4 (all P<0.001). Conclusion The recombinant plasmid pCDH-CMV-MCS-EF1-Puro/ARF4 and lentiviral vector LV-ARF4 were successfully constructed. The establishment of stably infected SKOV3 cell line with LV-ARF4 provides an experimental foundation for further studies on the biological function of ARF4 in ovarian cancer.

Objective To investigate the effect of vascular endothelial growth factor C (VEGF-C) on apoptosis of pancreatic cancer cell. Methods Human pancreatic cancer cell line PANC-1 orthotopic implantation tumor model was established in nude mice. Primary pancreatic cancer cells and that derived from lymphatic metastasis were primarily cultured. Expression of VEGF-C was inhibited through antisense oligodeoxynucleotide in vitro transfection. Reverse transcription polynlerase chain reaction (RT-PCR) and flow cytometer were used to detect the effect of VEGF-C on apoptosis of pancreatic cancer cells and bcl-2. Results After in vitro transfection, mRNA expression level of VEGF-C in PANC-1 pancreatic cancer cells significantly decreased (P ＜0. 01 ). Apoptosis rate of pancreatic cancer cells derived from spontaneous lymphatic metastasis was (2. 83 ± 1.01 ) %, ( 4. 98 ± 2. 05 ) %,and ( 13.22 ±2. 17) % respectively for control group, SODN group and ASODN group after in vitro transfection among which apoptosis rate in ASODN group increased significantly (P ＜0. 01 ). However, apoptosis rate for pancreatic cancer cells derived from primary tumor had no obvious change (P ＞0.05), with (3.51 ±1.38)%, (4.76 ±2. 16 ) %, and (5. 33 ± 2. 18 ) % respectively in control group, SODN group and ASODN group. The expression level of bcl-2 in pancreatic cancer cells derived from spontaneous lymphatic metastasis decreased significantly (P ＜0. 05) while it had no obvious change in primary pancreatic cancer cells (P ＞ 0. 05). Conclusion To inhibit expression of VEGF-C in pancreatic cancer cell can promote apoptosis of pancreatic cancer cell, which is relevant to downregulation of bcl-2;however, it has no obvious effect on primary pancreatic cancer.