Rhodiola crenulata root ameliorates derangements of glucose and lipid metabolism in a rat model of the metabolic syndrome and type 2 diabetes

The clustering of cardiovascular risk factors associated with the metabolic syndrome and type 2 diabetes suggests central mechanisms may exist that account for the presence of these abnormalities. Likewise, this clustering also suggests that key therapeutic targets may exist that could allow improvements in many of these parameters. Extensive data implicate peroxisome proliferator-activated receptor-alpha (PPARα) as an important transcriptional regulator of lipid metabolism, energy balance and inflammation. PPARα is also an established drug target. Experimental data show that activation of PPARα by agonists such as fenofibrate improves dyslipidaemia, increases cholesterol efflux and limits inflammation. All of these effects would also be predicted to decrease atherosclerotic risk. Evidence from surrogate markers in humans is also supportive of the concept that PPARα may act as a central target capable of influencing a variety of different pathways involved in lipid metabolism. Thus, fenofibrate offers the potential for inducing a co-ordinated PPARα response that may improve dyslipidaemia, repress inflammation and limit atherosclerosis in patients with the metabolic syndrome or type 2 diabetes.

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Adenovirus-mediated expression of SIK1 improves hepatic glucose and lipid metabolism in type 2 diabetes mellitus rats

10.1101/514299 ◽

2019 ◽

Author(s):

DaoFei Song ◽

Lei Yin ◽

Chang Wang ◽

XiuYing Wen

Keyword(s):

Diabetes Mellitus ◽

Type 2 Diabetes ◽

Type 2 Diabetes Mellitus ◽

Lipid Metabolism ◽

Rat Model ◽

Diabetic Rat ◽

Glucose And Lipid Metabolism ◽

Hepatic Glucose ◽

Element Binding Protein

AbstractAIMIn this study, we investigated the role and mechanism of Salt-induced kinase 1 (SIK1) in regulation of hepatic glucose and lipid metabolism in a high-fat food (HFD) and streptozocin (STZ)-induced type 2 diabetes mellitus (T2DM) rat model.MethodsA diabetic rat model treated with HFD plus low-dose STZ was developed and was transduced to induce a high expression of SIK1 in vivo via a tail-vein injection of a recombinant adenoviral vector. The effects on hepatic glucogenetic and lipogenic gene expression, systemic metabolism and pathological changes were then determined.ResultsIn T2DM rats, SIK1 expression was reduced in the liver. Overexpression of SIK1 improved hyperglycaemia, hyperlipidaemia and fatty liver, reduced the expression of cAMP-response element binding protein (CREB)-regulated transcription co-activator 2 (CRTC2), phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G6Pase), pS577 SIK1, sterol regulatory element binding-protein-1c (SREBP-1c) and its target genes, including acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), and increased the expression of SIK1, pT182 SIK1 and pS171 CRTC2 in diabetic rat livers with the suppression of gluconeogenesis and lipid deposition.ConclusionSIK1 plays a crucial role in the regulation of glucose and lipid metabolism in the livers of HFD/STZ-induced T2DM rats, where it suppresses hepatic gluconeogenesis and lipogenesis by regulating the SIK1/CRTC2 and SIK1/SREBP-1c signalling pathways. Strategies to activate SIK1 kinase in liver would likely have beneficial effects in patients with T2DM and nonalcoholic fatty liver disease (NAFLD).

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