title: Theobromine increases NAD⁺/Sirt-1 activity and protects the kidney under diabetic conditions.
abstract: Reduction in sirtuin 1 (Sirt-1) is associated with extracellular matrix (ECM) accumulation in the diabetic kidney. Theobromine may reduce kidney ECM accumulation in diabetic rats. In the current study, we aimed to unravel, under diabetic conditions, the mechanism of kidney ECM accumulation induced by a reduction in Sirt-1 and the effect of theobromine in these events. In vitro, we used immortalized human mesangial cells (iHMCs) exposed to high glucose (HG; 30 mM), with or without small interfering RNA for NOX4 and Sirt-1. In vivo, spontaneously hypertensive rats (SHR) were rendered diabetic by means of streptozotocin and studied after 12 wk. The effects of treatment with theobromine were investigated under both conditions. HG leads to a decrease in Sirt-1 activity and NAD(+) levels in iHMCs. Sirt-1 activity could be reestablished by treatment with NAD(+), silencing NOX4, and poly (ADP-ribose) polymerase-1 (PARP-1) blockade, or with theobromine. HG also leads to a low AMP/ATP ratio, acetylation of SMAD3, and increased collagen IV, which is prevented by theobromine. Sirt-1 or AMPK blockade abolished these effects of theobromine. In diabetic SHR, theobromine prevented increases in albuminuria and kidney collagen IV, reduced AMPK, elevated NADPH oxidase activity and PARP-1, and reduced NAD(+) levels and Sirt-1 activity. These results suggest that in diabetes mellitus, Sirt-1 activity is reduced by PARP-1 activation and NAD(+) depletion due to low AMPK, which increases NOX4 expression, leading to ECM accumulation mediated by transforming growth factor (TGF)-β1 signaling. It is suggested that Sirt-1 activation by theobromine may have therapeutic potential for diabetic nephropathy.
authors.affiliation: Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, São Paulo, Brazil.
authors.forename: Alexandros
authors.initials: A
authors.lastname: Papadimitriou
authors.affiliation: Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, São Paulo, Brazil.
authors.forename: Kamila C
authors.initials: KC
authors.lastname: Silva
authors.affiliation: Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, São Paulo, Brazil.
authors.forename: Elisa B M I
authors.initials: EB
authors.lastname: Peixoto
authors.affiliation: Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, São Paulo, Brazil.
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Borges
authors.affiliation: Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, São Paulo, Brazil.
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Lopes de Faria
authors.affiliation: Renal Pathophysiology Laboratory, Investigation on Diabetes Complications, Faculty of Medical Sciences, State University of Campinas (Unicamp), Campinas, São Paulo, Brazil jblfaria@fcm.unicamp.br.
authors.forename: José B
authors.initials: JB
authors.lastname: Lopes de Faria
mesh_terms: D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000378:metabolism*; D004195:Disease Models, Animal; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009243:NAD / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D017382:Reactive Oxygen Species / Q000378:metabolism*; D056564:Sirtuin 1 / Q000378:metabolism*; D013805:Theobromine / Q000494:pharmacology*
chemical_list: D017382:Reactive Oxygen Species; D009243:NAD; C499322:Parp1 protein, rat; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D056564:Sirtuin 1; D013805:Theobromine
keywords: AMPK; Sirt-1 (sirtuin 1); diabetic nephropathy; extracellular matrix accumulation; theobromine