Transcriptomic and proteomic analysis of potential therapeutic target genes in the liver of metformin‑treated Sprague‑Dawley rats with type 2 diabetes mellitus

Abstract

The main actions of metformin are as follows: To reduce hyperglycemia via the suppression of gluconeogenesis, improve glucose uptake and insulin sensitivity, and stimulate activation of adenosine monophosphate-activated protein kinase during the treatment of diabetes mellitus. It is well known that metformin acts via complex mechanisms, including multitarget and multipathway mechanisms; however, the multi-targeted antidiabetic genes of metformin remain obscure. The present study aimed to perform transcriptomic and proteomic analysis of potential therapeutic target genes in the liver of metformin-treated Sprague-Dawley rats with type 2 diabetes mellitus. The type 2 diabetes rat model was established using streptozotocin. Fasting blood glucose, hemoglobin A1c, serum insulin and biological parameters were subsequently measured. Differentially expressed genes (DEGs) and proteins were identified in the rat livers by expression profile analysis and isobaric tags for relative and absolute quantitation (iTRAQ). A 1.5-fold alteration in gene expression, as determined using chip-based expression profile analysis, and a 1.2-fold alteration in protein expression, as determined using iTRAQ, were considered physiologically significant benchmarks, which were used to identify DEGS in metformin-treated rats with type 2 diabetes mellitus. The DEGs were verified using quantitative polymerase chain reaction (qPCR) and western blot analysis. Numerous hepatic genes involved in various metabolic pathways were affected by metformin; in particular, genes associated with lipid metabolism were markedly affected. Expression profile analysis and iTRAQ analysis suggested that carboxylesterase 1C subunit (Ces1C) and cholesterol 7α-hydroxylyase (Cyp7a1) may serve as important DEGs, which were validated by qPCR and western blot analysis. Ces1C and Cyp7a1 are the main enzymes in cholesterol metabolism, yet the result of western blotting was not consistent with qPCR. The present study demonstrated that metformin may affect the expression of numerous hepatic genes involved in metabolic pathways, particularly the lipid and cholesterol metabolic pathways. Ces1C and Cyp7a1 may be considered novel therapeutic target genes in the liver, which are involved in the antidiabetic effects of metformin.

Integrated 16S rRNA Sequencing, Metagenomics, and Metabolomics to Characterize Gut Microbial Composition, Function, and Fecal Metabolic Phenotype in Non-obese Type 2 Diabetic Goto-Kakizaki Rats

“…KEGG analysis further indicated that these perturbed gut bacteria in GK rats were strongly associated with the dysregulation of some metabolic processes such as glyoxylate and dicarboxylate metabolism; porphyrin and chlorophyll metabolism; and glycine, serine, and threonine metabolism. Interestingly, the five COG categories enriched in our study, in addition to glyoxylate and dicarboxylate metabolism, have been implicated in the antidiabetic effects of metformin (Dong et al, 2016;Chen et al, 2018).…”

A Possible Mechanism of Metformin in Improving Insulin Resistance in Diabetic Rat Models

“…A growing number of research is interested in the effects of metformin on endogenous BA, and whether BA signaling can explain its effect on improving insulin sensitivity, so we determined that metformin regulates the pathway of sterol 12 α -hydroxylase CYP8B1. Metformin is effective in lowering blood glucose [16], reducing body weight [17], and improving insulin resistance [18] and has been widely studied for its importance in the treatment of diabetes [19]. The main pathway for cholesterol catabolism is the formation of bile acids [20].…”

<p>Effects of Hydroxysafflor Yellow A on the PI3K/AKT Pathway and Apoptosis of Pancreatic β-Cells in Type 2 Diabetes Mellitus Rats</p>

“…Although HDL-C had the antioxidant and anti-inflammatory effects 22 and some studies 23,24 showed that the HDL-C level in T2DM rats would be higher than that of the normal rats, our founding suggested that there was no statistical difference between them as the previous study. 25 In this study, the T2DM rats indicated a decrease in acinar staining intensity that reflecting the defects in digestive function of the pancreas. The insulin granules and their intensity in β-cells were reduced in T2DM rats, and HSYA could reverse the impaired islets β-cells as shown in the Immunohistochemical results.…”