AIM:To explore the role and molecular mechanism of Men1 gene in regulating mouse renal fibro-sis.METHODS:A unilateral ureteral obstruction(UUO)-induced renal fibrosis model was established using C57BL/6 mice,and the mice were randomly divided into 4 groups:sham,UUO-3 d,UUO-7 d,and UUO-14 d,with 15 mice in each group.The C57BL/6 mice with Men1 knockout were randomly divided into 4 groups:sham-Men1-WT,sham-Men1-CKO,UUO-Men1-WT,and UUO-Men1-CKO,with 8 mice in each group.HE staining,Masson staining,and Sirius red staining were used to detect UUO-induced renal injury and renal fibrosis.Human renal tubular epithelial HK-2 cells with MEN1 knockout were constructed.RT-qPCR,Western blot,immunohistochemistry and immunoflurorescnence were per-formed to detect the mRNA and protein expression of MEN1,fibrosis markers(α-smooth muscle actin,collagen type Ⅲ and fibronectin 1)and m6A-related proteins[methyltransferase-like 3(METTL3),METTL14,YTH domain family pro-tein 2(YTHDF2),AlkB homolog 5(ALKBH5),and fat mass and obesity-associated protein(FTO)]in UUO mouse kid-ney tissues and transforming growth factor-β(TGF-β;10 μg/L)-treated HK-2 cells.Dot blot analysis was conducted to measure m6A methylation levels in both mouse kidney tissuess and HK-2 cells.RESULTS:The expression of Men1 de-creased with the aggravation of renal fibrosis(P＜0.01).Men1 inhibited the expression of fibrosis markers in renal tis-sues,and MEN1 knockout increased the accumulation of collagen induced by UUO and TGF-β(P＜0.01).The expres-sion of FTO and ALKBH5 in mouse kidney tissues and HK-2 cells was down-regulated by MEN1 knockout(P＜0.01),and the methylation level of m6A was increased(P＜0.01).Overexpression of FTO significantly reduced the accumulation of m6A modifications and renal fibrosis caused by MEN1 loss,and the methylation level of m6A was increased(P＜0.01).CONCLUSION:Loss of Men1 gene promotes renal fibrosis in mice,and Men1 suppresses renal fibrosis in mice by pro-moting the expression of FTO/ALKBH5 to reduce m6A modifications.

AIM:To explore the role and molecular mechanism of Men1 gene in regulating mouse renal fibro-sis.METHODS:A unilateral ureteral obstruction(UUO)-induced renal fibrosis model was established using C57BL/6 mice,and the mice were randomly divided into 4 groups:sham,UUO-3 d,UUO-7 d,and UUO-14 d,with 15 mice in each group.The C57BL/6 mice with Men1 knockout were randomly divided into 4 groups:sham-Men1-WT,sham-Men1-CKO,UUO-Men1-WT,and UUO-Men1-CKO,with 8 mice in each group.HE staining,Masson staining,and Sirius red staining were used to detect UUO-induced renal injury and renal fibrosis.Human renal tubular epithelial HK-2 cells with MEN1 knockout were constructed.RT-qPCR,Western blot,immunohistochemistry and immunoflurorescnence were per-formed to detect the mRNA and protein expression of MEN1,fibrosis markers(α-smooth muscle actin,collagen type Ⅲ and fibronectin 1)and m6A-related proteins[methyltransferase-like 3(METTL3),METTL14,YTH domain family pro-tein 2(YTHDF2),AlkB homolog 5(ALKBH5),and fat mass and obesity-associated protein(FTO)]in UUO mouse kid-ney tissues and transforming growth factor-β(TGF-β;10 μg/L)-treated HK-2 cells.Dot blot analysis was conducted to measure m6A methylation levels in both mouse kidney tissuess and HK-2 cells.RESULTS:The expression of Men1 de-creased with the aggravation of renal fibrosis(P＜0.01).Men1 inhibited the expression of fibrosis markers in renal tis-sues,and MEN1 knockout increased the accumulation of collagen induced by UUO and TGF-β(P＜0.01).The expres-sion of FTO and ALKBH5 in mouse kidney tissues and HK-2 cells was down-regulated by MEN1 knockout(P＜0.01),and the methylation level of m6A was increased(P＜0.01).Overexpression of FTO significantly reduced the accumulation of m6A modifications and renal fibrosis caused by MEN1 loss,and the methylation level of m6A was increased(P＜0.01).CONCLUSION:Loss of Men1 gene promotes renal fibrosis in mice,and Men1 suppresses renal fibrosis in mice by pro-moting the expression of FTO/ALKBH5 to reduce m6A modifications.