title: Ubiquitin C-terminal hydrolase-L5 is required for high glucose-induced transforming growth factor-β receptor I expression and hypertrophy in mesangial cells.
abstract: Transforming growth factor-β (TGF-β) is pivotal in the pathogenesis of diabetic nephropathy. Type 1 TGF-β receptor (TGF-βR1) is degraded by Smad7-dependent ubiquitination-proteasomal pathway, which is deubiquitinated by ubiquitin C-terminal hydrolase-L5 (UCHL5). Therefore, we studied the role of UCHL5 in high glucose (27.8mM)-induced TGF-βR1 protein expression in mouse mesangial (MES13) cells. UCHL5 short hairpin RNA (shRNA) was used to knock down UCHL5 while LY294002 and the dominant-negative p85 were used to inhibit phosphatidylinositol-3-kinase (PI3K). We found that high glucose increased phospho-Akt, TGF-βR1 mRNA and protein expression. High glucose also increased UCHL5 protein expression, which was attenuated by LY294002, the dominant-negative p85 and the dominant-negative CREB. High glucose-induced TGF-βR1 protein expression and TGF-βR1 protein deubiquitination were attenuated by UCHL5 shRNA. Additionally, high glucose-induced p21(WAF1), fibronectin protein expression and cell hypertrophy were attenuated by UCHL5 shRNA. However, high glucose-induced TGF-βR1 mRNA, p27(kip1) protein expression and growth inhibition were not affected by UCHL5 shRNA. Finally, glomerular UCHL5 and TGF-βR1 protein expression were increased in streptozotocin-diabetic rats at 8weeks. We conclude that PI3K-dependent UCHL5 is required for high glucose-induced TGF-βR1 protein expression in mesangial cells. UCHL5 is also required for high glucose-induced TGF-βR1 protein deubiquitination, p21(WAF1) and fibronectin protein expression and cell hypertrophy.
authors.affiliation: Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Taiwan.
authors.forename: Yu-Min
authors.initials: YM
authors.lastname: Ko
authors.forename: Chun-Ying
authors.initials: CY
authors.lastname: Chang
authors.forename: Shean-Jaw
authors.initials: SJ
authors.lastname: Chiou
authors.forename: Fu-Jie
authors.initials: FJ
authors.lastname: Hsu
authors.forename: Jau-Shyang
authors.initials: JS
authors.lastname: Huang
authors.forename: Yu-Lin
authors.initials: YL
authors.lastname: Yang
authors.forename: Jinn-Yuh
authors.initials: JY
authors.lastname: Guh
authors.forename: Lea-Yea
authors.initials: LY
authors.lastname: Chuang
mesh_terms: D000818:Animals; D002268:Carboxypeptidases / Q000378:metabolism*; D002460:Cell Line; D048429:Cell Size; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D007678:Kidney Glomerulus / Q000378:metabolism; D007684:Kidney Tubules / Q000378:metabolism; D008297:Male; D050527:Mesangial Cells / Q000166:cytology* / Q000378:metabolism*; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*; D043222:Ubiquitin Thiolesterase
chemical_list: D002268:Carboxypeptidases; D017362:Cyclic AMP Response Element-Binding Protein; D050759:Cyclin-Dependent Kinase Inhibitor p21; D005353:Fibronectins; D005947:Glucose; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta; D043222:Ubiquitin Thiolesterase; C493957:Cdkn1a protein, mouse; C000625843:Tgfbr1 protein, rat; C581032:Uchl5 protein, mouse