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Aminoguanidine reduces diabetes-associated cardiac fibrosis.

ABSTRACT: Aminoguanidine (AG) inhibits advanced glycation end products (AGEs) and advanced oxidation protein products (AOPP) accumulated as a result of excessive oxidative stress in diabetes. However, the molecular mechanism by which AG reduces AGE-associated damage in diabetes is not well understood. Thus, we investigated whether AG supplementation mitigates oxidative-associated cardiac fibrosis in rats with type 2 diabetes mellitus (T2DM). Forty-five male Wistar rats were divided into three groups: Control, T2DM and T2DM+AG. Rats were fed with a high-fat, high-carbohydrate diet (HFCD) for 2 weeks and rendered diabetic using low-dose streptozotocin (STZ) (20 mg/kg), and one group was treated with AG (20 mg/kg) up to 25 weeks. In vitro experiments were performed in primary rat myofibroblasts to confirm the antioxidant and antifibrotic effects of AG and to determine if blocking the receptor for AGEs (RAGE) prevents the fibrogenic response in myofibroblasts. Diabetic rats exhibited an increase in cardiac fibrosis resulting from HFCD and STZ injections. By contrast, AG treatment significantly reduced cardiac fibrosis, ?-smooth muscle actin (?SMA) and oxidative-associated Nox4 and Nos2 mRNA expression. In vitro challenge of myofibroblasts with AG under T2DM conditions reduced intra- and extracellular collagen type I expression and Pdgfb, Tgf?1 and Col1a1 mRNAs, albeit with similar expression of Tnf? and Il6 mRNAs. This was accompanied by reduced phosphorylation of ERK1/2 and SMAD2/3 but not of AKT1/2/3 and STAT pathways. RAGE blockade further attenuated collagen type I expression in AG-treated myofibroblasts. Thus, AG reduces oxidative stress-associated cardiac fibrosis by reducing pERK1/2, pSMAD2/3 and collagen type I expression via AGE/RAGE signaling in T2DM.

SUBMITTER: Magdaleno F

PROVIDER: S-EPMC6755450 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

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Aminoguanidine reduces diabetes-associated cardiac fibrosis.

Magdaleno Fernando F Blajszczak Chuck Christopher CC Charles-Niño Claudia Lisette CL Guadrón-Llanos Alma Marlene AM Vázquez-Álvarez Alan Omar AO Miranda-Díaz Alejandra Guillermina AG Nieto Natalia N Islas-Carbajal María Cristina MC Rincón-Sánchez Ana Rosa AR

Experimental and therapeutic medicine 20190820 4

Aminoguanidine (AG) inhibits advanced glycation end products (AGEs) and advanced oxidation protein products (AOPP) accumulated as a result of excessive oxidative stress in diabetes. However, the molecular mechanism by which AG reduces AGE-associated damage in diabetes is not well understood. Thus, we investigated whether AG supplementation mitigates oxidative-associated cardiac fibrosis in rats with type 2 diabetes mellitus (T2DM). Forty-five male Wistar rats were divided into three groups: Cont ...[more]

PMID: 31572553

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Project description:BACKGROUND:Heart failure is a growing cause of morbidity and mortality worldwide. Transforming growth factor beta (TGF-?1) promotes cardiac fibrosis, but also activates counterregulatory pathways that serve to regulate TGF-?1 activity in heart failure. Bone morphogenetic protein 9 (BMP9) is a member of the TGF? family of cytokines and signals via the downstream effector protein Smad1. Endoglin is a TGF? coreceptor that promotes TGF-?1 signaling via Smad3 and binds BMP9 with high affinity. We hypothesized that BMP9 limits cardiac fibrosis by activating Smad1 and attenuating Smad3, and, furthermore, that neutralizing endoglin activity promotes BMP9 activity. METHODS:We examined BMP9 expression and signaling in human cardiac fibroblasts and human subjects with heart failure. We used the transverse aortic constriction-induced model of heart failure to evaluate the functional effect of BMP9 signaling on cardiac remodeling. RESULTS:BMP9 expression is increased in the circulation and left ventricle (LV) of human subjects with heart failure and is expressed by cardiac fibroblasts. Next, we observed that BMP9 attenuates type I collagen synthesis in human cardiac fibroblasts using recombinant human BMP9 and a small interfering RNA approach. In BMP9-/- mice subjected to transverse aortic constriction, loss of BMP9 activity promotes cardiac fibrosis, impairs LV function, and increases LV levels of phosphorylated Smad3 (pSmad3), not pSmad1. In contrast, treatment of wild-type mice subjected to transverse aortic constriction with recombinant BMP9 limits progression of cardiac fibrosis, improves LV function, enhances myocardial capillary density, and increases LV levels of pSmad1, not pSmad3 in comparison with vehicle-treated controls. Because endoglin binds BMP9 with high affinity, we explored the effect of reduced endoglin activity on BMP9 activity. Neutralizing endoglin activity in human cardiac fibroblasts or in wild-type mice subjected to transverse aortic constriction-induced heart failure limits collagen production, increases BMP9 protein levels, and increases levels of pSmad1, not pSmad3. CONCLUSIONS:Our results identify a novel functional role for BMP9 as an endogenous inhibitor of cardiac fibrosis attributable to LV pressure overload and further show that treatment with either recombinant BMP9 or disruption of endoglin activity promotes BMP9 activity and limits cardiac fibrosis in heart failure, thereby providing potentially novel therapeutic approaches for patients with heart failure.

Dataset Information

Aminoguanidine reduces diabetes-associated cardiac fibrosis.

Publications

Aminoguanidine reduces diabetes-associated cardiac fibrosis.

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