MicroRNAs (miRNAs), a class of endogenous small noncoding RNAs in eukaryotes, have been recognized as significant regulators of gene expression through post-transcriptional mechanisms. To date, >2000 miRNAs have been identified in the human genome, and they orchestrate a variety of biological and pathological processes. Disruption of miRNA levels correlates with many diseases, including diabetes mellitus, a complex multifactorial metabolic disorder affecting >400 million people worldwide. miRNAs are involved in the pathogenesis of diabetes mellitus by affecting pancreatic β-cell functions, insulin resistance, or both. In this review, we summarize the investigations of the regulatory roles of important miRNAs in diabetes, as well as the potential of circulating miRNAs as diagnostic markers for diabetes mellitus.

Emerging in vivo and vitro data suggest that white tea extract (WTE) is capable of favourably modulating metabolic syndrome, especially by ameliorating abnormal lipid metabolism. Microarray-based gene expression profiling was performed in HepG2 cells to analyze the effects of WTE from a systematic perspective. Gene Ontology and pathway analysis revealed that WTE significantly affected pathways related to lipid metabolism. WTE significantly downregulated apolipoprotein B (APOB) and microsomal triglyceride transfer protein (MTTP) expression and thereby reduced the production of very-low-density lipoprotein. In the meanwhile, WTE stimulated low-density lipoprotein-cholesterol (LDL-c) uptake through targeting low-density lipoprotein receptor (LDLR), as a consequence of the activation of sterol regulatory element-binding protein 2 (SREBP2) and peroxisome proliferator-activated receptor δ (PPARδ). Furthermore, WTE significantly downregulated triglycerides synthetic genes and reduced intracellular triglycerides accumulation. Besides, we demonstrated that the tea catechins epigallocatechin-3-gallate (EGCG) and epicatechin-3-gallate (ECG) are abundant in WTE and contribute to the regulation of cholesterol metabolism related genes, including LDLR, MTTP and APOB. Our findings suggest white tea plays important roles in ameliorating abnormal lipid metabolism in vitro.

Serum response factor (SRF) is a widely expressed transcription factor involved in multiple regulatory programs. It is believed that SRF can toggle between disparate programs of gene expression through association with different cofactors. However, the direct evidence as to how these factors function on a genome-wide level is still lacking.

Medicinal plants show important therapeutic value in chronic disease treatment. However, due to their diverse ingredients and complex biological effects, the molecular mechanisms of medicinal plants are yet to be explored. By means of several high-throughput platforms, here we show hawk tea extract (HTE) inhibits Niemann–Pick C1-like 1 (NPC1L1)-mediated free cholesterol uptake, thereby inducing the transcription of low-density lipoprotein receptor (LDLR) downstream of the sterol response element binding protein 2 (SREBP2) pathway. Meanwhile, HTE suppresses hepatocyte nuclear factor 4α (HNF4α)-mediated transcription of microsomal triglyceride transfer protein (MTP) and apolipoprotein B (APOB), thereby decreasing the production of very-low-density lipoprotein. The catechin EGCG ((−)-epigallocatechin gallate) and the flavonoids kaempferol and quercetin are identified as the bioactive components responsible for the effects on the NPC1L1-SREBP2-LDLR axis and HNF4α-MTP/APOB axis, respectively. Overall, hawk tea works as a previously unrecognized cholesterol-lowering agent in a multi-target and multi-component manner.