Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011854 (type 1 diabetes)
 20,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Natural product berberine (BBR) has been reported to have hypoglycemic and insulin-sensitizing activities; however, its mechanism remains unclear. This study was designed to investigate the molecular mechanism of BBR against insulin resistance. Here, we identify insulin receptor (InsR) as a target of BBR to increase insulin sensitivity. In cultured human liver cells, BBR increased InsR messenger RNA (mRNA) and protein expression in a dose- and time-dependent manner. Berberine increased InsR expression in the L6 rat skeletal muscle cells as well. Berberine-enhanced InsR expression improved cellular glucose consumption only in the presence of insulin. Silencing InsR gene with small interfering RNA or blocking the phosphoinositol-3-kinase diminished this effect. Berberine induced InsR gene expression through a protein kinase C (PKC)-dependent activation of its promoter. Inhibition of PKC abolished BBR-caused InsR promoter activation and InsR mRNA transcription. In animal models, treatment of type 2 diabetes mellitus rats with BBR lowered fasting blood glucose and fasting serum insulin, increased insulin sensitivity, and elevated InsR mRNA as well as PKC activity in the liver. In addition, BBR lowered blood glucose in KK-Ay type 2 but not in NOD/LtJ type 1 diabetes mellitus mice that were insulin deficient. Our results suggest that BBR is a unique natural medicine against insulin resistance in type 2 diabetes mellitus and metabolic syndrome.
 ...
PMID:Berberine reduces insulin resistance through protein kinase C-dependent up-regulation of insulin receptor expression. 1905 38

Berberine, an alkaloid derivative from Berberis vulgaris L., has been used extensively in traditional Chinese medicine to treat diarrhea and diabetes, but the underlying mechanisms for treating diabetes are not fully understood. Recent studies suggested that berberine has many beneficial biological effects, including anti-inflammation. Because type 1 diabetes is caused by T cell-mediated destruction of beta cells and severe islet inflammation, we hypothesized that berberine could ameliorate type 1 diabetes through its immune regulation properties. Here we reported that 2 weeks of oral administration of berberine prevented the progression of type 1 diabetes in half of the NOD mice and decreased Th17 and Th1 cytokine secretion. Berberine suppressed Th17 and Th1 differentiation by reducing the expression of lineage markers. We found that berberine inhibited Th17 differentiation by activating ERK1/2 and inhibited Th1 differentiation by inhibiting p38 MAPK and JNK activation. Berberine down-regulated the activity of STAT1 and STAT4 through the suppression of p38 MAPK and JNK activation, and it controlled the stability of STAT4 through the ubiquitin-proteasome pathway. Our findings indicate that berberine targets MAPK to suppress Th17 and Th1 differentiation in type 1 diabetic NOD mice. This study revealed a novel role of ERK in Th17 differentiation through down-regulation of STAT3 phosphorylation and RORgamma t expression.
 ...
PMID:Berberine differentially modulates the activities of ERK, p38 MAPK, and JNK to suppress Th17 and Th1 T cell differentiation in type 1 diabetic mice. 1966 Oct 66