〔Abstract〕 Objective To investigate whether TYRO protein tyrosine kinase-binding protein(TYROBP) affects the progression of diabetic kidney disease(DKD) through the extracellular signal-regulated kinase(ERK) pathway.Methods Key genes in DKD were identified through bioinformatics analysis.Immunohistochemical staining and quantitative real-time PCR(qPCR) were used to validate the expression levels of TYROBP in a DKD mouse model and high glucose-stimulated NRK-52E cells.NRK-52E cell models with stable TYROBP overexpression/knockdown and their corresponding empty vector(ev)/scrambled sequence(ss) controls were established via lentiviral transfection.Cells were treated with 5.5 mmol/L or 30.0 mmol/L glucose for 72 hours to mimic normal glucose(NG)and high glucose(HG) conditions,respectively.High glucose medium containing 3.5 μmol/L FR180204 was used for ERK inhibitor intervention.The experiment included seven groups:ev+NG,ev+HG,oe-TYROBP+HG,ss+NG,ss+HG,sh-TYROBP+HG,and sh-TYROBP+HG+ERK inhibitor.Western blot was used to detect the expression levels of phosphorylated ERK/total ERK(p-ERK/ERK),apoptosis-related proteins B-cell lymphoma-2(Bcl-2) and Bcl-2-associated X protein(Bax),and epithelial-mesenchymal transition(EMT)-related proteins E-cadherin and α-smooth muscle actin(α-SMA).Tetramethylrhodamine ethyl ester(TMRE) staining and Annexin V-fluorescein isothiocyanate/propidium iodide(Annexin V-FITC/PI) flow cytometry were performed to assess mitochondrial membrane potential and apoptosis levels.Results Bioinformatics analysis identified TYROBP as a key gene in DKD.In vivo and in vitro validation showed increased TYROBP mRNA levels in DKD models.The results from the HG model indicated that,compared to the ev+NG/ss+NG group,the ev+HG/ss+HG group demonstrated increased p-ERK/ERK expression,reduced mitochondrial membrane potential,elevated apoptosis,and enhanced EMT.In TYRO BP-perturbed NRK-52E cells,compared to the ev+HG group,the oe-TYROBP+HG group showed decreased p-ERK/ERK expression(P