AIM:To investigate the regulatory mechanism of silent information regulator 6(Sirt6)on nuclear factor E2-related factor 2(Nrf2)/heme oxygenase-1(HO-1)signaling pathway and ferroptosis in skeletal muscle aging in-duced by D-galactose(D-Gal)in mice.METHODS:A D-Gal-induced mouse aging model was established and randomly divided into control and D-Gal groups.In vitro,D-Gal-treated C2C12 mouse myoblasts were treated with ferroptosis ago-nist erastin(Era)and inhibitor ferrostatin-1(Fer-1),Sirt6 agonist MDL-800 and inhibitor OSS-128167,and Nrf2 siRNA.Mouse body weight and forelimb relative grip strength were monitored.RT-qPCR and Western blot were used to measure the expression of Sirt6,Nrf2,HO-1,P53,P21,P16,muscle ring finger protein 1,muscle atrophy F-box,solute carrier family 7 member 11,and glutathione peroxidase 4 in gastrocnemius muscle and myoblasts.Hematoxylin-eosin staining was performed to examine muscle fiber diameter.Levels of reactive oxygen species(ROS),mitochondrial ROS,mitochon-drial membrane potential,senescence-associated β-galactosidase activity,glutathione,lipid peroxidation,and Fe2? con-centration were measured in myoblasts and myotubes.Immunofluorescence staining was used to detect myosin heavy chain(MyHC)expression in myotubes.RESULTS:Mice in the D-Gal group exhibited significant reductions in body weight and forelimb grip strength(P<0.01),upregulation of aging and muscle atrophy markers,and decreased mRNA and pro-tein levels of ferroptosis markers and Sirt6(P<0.01).Additionally,gastrocnemius muscle fiber diameter significantly de-creased(P<0.01).In D-Gal-treated myoblasts and myotubes,aging and muscle atrophy markers were elevated(P<0.01),MyHC expression was reduced,and protein levels of ferroptosis-related markers,Sirt6,Nrf2,and HO-1 were de-creased(P<0.05 or P<0.01).Fer-1 pre-treatment alleviated these changes(P<0.05 or P<0.01).MDL-800 significantly improved D-Gal-induced aging and muscle atrophy in myoblasts and myotubes,while increasing the expression of ferropto-sis-related proteins(P<0.05 or P<0.01).However,the addition of Erastin abolished the beneficial effects of MDL-800(P<0.05 or P<0.01).Following Nrf2 siRNA transfection,the ability of MDL-800 to improve ferroptosis and the quality of myotube formation was significantly diminished(P<0.05 or P<0.01).CONCLUSION:Sirt6 inhibits ferroptosis in myo-blasts through the Nrf2/HO-1 signaling pathway,thereby alleviating age-related changes in myoblasts and the decline in myotube formation quality,which is beneficial for improving skeletal muscle aging.

AIM:To investigate the immunosuppressive effects of M2-like tumor-associated macrophages(M2-TAMs)on CD8+T cells within the tumor microenvironment of esophageal cancer.METHODS:Multiplex fluores-cence immunohistochemistry was used to analyze the distribution of immune cells in esophageal cancer tissues.An in vitro co-culture system was established,and flow cytometry along with Calcein-AM/PI staining was employed to assess the im-pact of M2-TAMs on CD8+T cell function.The GEPIA database was utilized to evaluate the prognostic significance of PDCD1 expression in esophageal cancer patients and to analyze the correlations between gene expressions.Immunohisto-chemistry(IHC)was performed to detect the expression of TGF-β1 in esophageal cancer tissues.Flow cytometry and en-zyme-linked immunosorbent assay(ELISA)were used to measure PD-1,IFN-γ and TNF-α expression in CD8+T cells fol-lowing treatment with a TGF-β1 inhibitor.RESULTS:Compared with early-stage(stage I)esophageal cancer patients,the patients with advanced disease(stages Ⅱ to Ⅳ)exhibited dynamic changes in the infiltration of CD4+T cells,CD8+T cells,Tregs,and M2-TAMs within tumor tissues,with significant correlations observed among these cell populations(P<0.05).The distribution of M2-TAMs and Tregs was positively correlated with poor prognosis(P<0.05),while that of CD8+T cells was negatively correlated(P<0.05).In contrast,CD4+T cell infiltration showed no significant association with clinical outcomes(P>0.05).Co-culture of CD8+T cells with M2-TAMs resulted in significant downregulation of CD107a,granzyme B,IFN-γ and TNF-α expression(P<0.01).Additionally,M2-TAM-treated CD8+T cells co-cultured with esophageal cancer cells led to reduced apoptosis of cancer cells.High expression of PDCD1 was significantly associated with poor prognosis(P<0.05),and significant correlations were observed between CD8A and PDCD1 expression,as well as between TGF-β1 and CD274 gene expression(P<0.01).TGF-β1 was also significantly associated with CD163+macro-phage infiltration and the progression of esophageal cancer(P<0.05).Treatment with a TGF-β1 inhibitor in the M2-TAM and CD8+T cell co-culture system significantly down-regulated PD-1 expression and increased the secretion of IFN-γ and TNF-α(P<0.01).CONCLUSION:The TGF-β1 derived from M2-TAMs inhibits the antitumor activity of CD8+T cells in the esophageal cancer microenvironment,suggesting potential therapeutic targets for overcoming immunosuppression in esophageal cancer.

AIM:To investigate the regulatory mechanism of silent information regulator 6(Sirt6)on nuclear factor E2-related factor 2(Nrf2)/heme oxygenase-1(HO-1)signaling pathway and ferroptosis in skeletal muscle aging in-duced by D-galactose(D-Gal)in mice.METHODS:A D-Gal-induced mouse aging model was established and randomly divided into control and D-Gal groups.In vitro,D-Gal-treated C2C12 mouse myoblasts were treated with ferroptosis ago-nist erastin(Era)and inhibitor ferrostatin-1(Fer-1),Sirt6 agonist MDL-800 and inhibitor OSS-128167,and Nrf2 siRNA.Mouse body weight and forelimb relative grip strength were monitored.RT-qPCR and Western blot were used to measure the expression of Sirt6,Nrf2,HO-1,P53,P21,P16,muscle ring finger protein 1,muscle atrophy F-box,solute carrier family 7 member 11,and glutathione peroxidase 4 in gastrocnemius muscle and myoblasts.Hematoxylin-eosin staining was performed to examine muscle fiber diameter.Levels of reactive oxygen species(ROS),mitochondrial ROS,mitochon-drial membrane potential,senescence-associated β-galactosidase activity,glutathione,lipid peroxidation,and Fe2? con-centration were measured in myoblasts and myotubes.Immunofluorescence staining was used to detect myosin heavy chain(MyHC)expression in myotubes.RESULTS:Mice in the D-Gal group exhibited significant reductions in body weight and forelimb grip strength(P<0.01),upregulation of aging and muscle atrophy markers,and decreased mRNA and pro-tein levels of ferroptosis markers and Sirt6(P<0.01).Additionally,gastrocnemius muscle fiber diameter significantly de-creased(P<0.01).In D-Gal-treated myoblasts and myotubes,aging and muscle atrophy markers were elevated(P<0.01),MyHC expression was reduced,and protein levels of ferroptosis-related markers,Sirt6,Nrf2,and HO-1 were de-creased(P<0.05 or P<0.01).Fer-1 pre-treatment alleviated these changes(P<0.05 or P<0.01).MDL-800 significantly improved D-Gal-induced aging and muscle atrophy in myoblasts and myotubes,while increasing the expression of ferropto-sis-related proteins(P<0.05 or P<0.01).However,the addition of Erastin abolished the beneficial effects of MDL-800(P<0.05 or P<0.01).Following Nrf2 siRNA transfection,the ability of MDL-800 to improve ferroptosis and the quality of myotube formation was significantly diminished(P<0.05 or P<0.01).CONCLUSION:Sirt6 inhibits ferroptosis in myo-blasts through the Nrf2/HO-1 signaling pathway,thereby alleviating age-related changes in myoblasts and the decline in myotube formation quality,which is beneficial for improving skeletal muscle aging.

AIM:To investigate the immunosuppressive effects of M2-like tumor-associated macrophages(M2-TAMs)on CD8+T cells within the tumor microenvironment of esophageal cancer.METHODS:Multiplex fluores-cence immunohistochemistry was used to analyze the distribution of immune cells in esophageal cancer tissues.An in vitro co-culture system was established,and flow cytometry along with Calcein-AM/PI staining was employed to assess the im-pact of M2-TAMs on CD8+T cell function.The GEPIA database was utilized to evaluate the prognostic significance of PDCD1 expression in esophageal cancer patients and to analyze the correlations between gene expressions.Immunohisto-chemistry(IHC)was performed to detect the expression of TGF-β1 in esophageal cancer tissues.Flow cytometry and en-zyme-linked immunosorbent assay(ELISA)were used to measure PD-1,IFN-γ and TNF-α expression in CD8+T cells fol-lowing treatment with a TGF-β1 inhibitor.RESULTS:Compared with early-stage(stage I)esophageal cancer patients,the patients with advanced disease(stages Ⅱ to Ⅳ)exhibited dynamic changes in the infiltration of CD4+T cells,CD8+T cells,Tregs,and M2-TAMs within tumor tissues,with significant correlations observed among these cell populations(P<0.05).The distribution of M2-TAMs and Tregs was positively correlated with poor prognosis(P<0.05),while that of CD8+T cells was negatively correlated(P<0.05).In contrast,CD4+T cell infiltration showed no significant association with clinical outcomes(P>0.05).Co-culture of CD8+T cells with M2-TAMs resulted in significant downregulation of CD107a,granzyme B,IFN-γ and TNF-α expression(P<0.01).Additionally,M2-TAM-treated CD8+T cells co-cultured with esophageal cancer cells led to reduced apoptosis of cancer cells.High expression of PDCD1 was significantly associated with poor prognosis(P<0.05),and significant correlations were observed between CD8A and PDCD1 expression,as well as between TGF-β1 and CD274 gene expression(P<0.01).TGF-β1 was also significantly associated with CD163+macro-phage infiltration and the progression of esophageal cancer(P<0.05).Treatment with a TGF-β1 inhibitor in the M2-TAM and CD8+T cell co-culture system significantly down-regulated PD-1 expression and increased the secretion of IFN-γ and TNF-α(P<0.01).CONCLUSION:The TGF-β1 derived from M2-TAMs inhibits the antitumor activity of CD8+T cells in the esophageal cancer microenvironment,suggesting potential therapeutic targets for overcoming immunosuppression in esophageal cancer.

Objective:To investigate the feasibility of cone-beam CT (CBCT) in evaluating the thickness of cortical bone in jaw bone.Methods:Sixty patients [twenty-three for males and forty-seven for females, at an average age of (43.8±1.7) years] from Center of Stomatology, The First Affiliated Hospital of USTC & Anhui Provincial Hospital with 63 operational regions were included in the present study. Totally 63 bone sections from these areas were all selected at last. Case Viewer and oral dynamic system were used for the measurements in sections and CBCT graphs of the cortical bone thicknesses at alveolar ridges. Paired samples t test was performed to compare the difference between CBCT measurement and Case Viewer measurement. Results:The cortical bone thicknesses measured by Case Viewer were (1.20±0.75), (0.68±0.46) and (1.48±0.77) mm in the posterior, maxillary posterior and mandibular posterior areas, respectively. The cortical bone thicknesses measured by dynamic navigation software were (1.14±0.77), (0.64±0.24) and (1.41±0.83) mm in the posterior, maxillary posterior and mandibular posterior areas, respectively. There were no significant differences between either the two methods or the different areas ( P>0.05). Conclusions:CBCT would be a useful equipment for the analysis of cortical bone thickness with a reliable and convincible accuracy.