Global Liver Gene Expression Analysis on a Murine Hepatic Steatosis Model Treated with Mulberry (Morus alba L.) Leaf Powder

Abstract

Background/aim: Mulberry (Morus alba L.) leaves (ML) contain many functional components, such as 1-deoxynojirimycin, flavonoids (rutin, quercetin, kaempferol). It is well known that 1-deoxynojirimycin functions to suppress increases in blood glucose level by α-glucosidase inhibitory activity. Thus, the molecular mechanism underlying the protective and therapeutic effects of ML supplementation was investigated on a mouse model of high-calorie diet (Western diet: WD)-induced hepatic steatosis (HS).

Materials and methods: The C57BL/6J mouse was used for the HS model. The mice were divided into three groups: control (normal diet: ND), WD, and WD + 1% ML groups. The WD group was fed a high-calorie (high carbohydrate and high fat) diet for 12 weeks to develop HS. At week 12, all mice were sacrificed, blood was collected for biochemical tests, and the liver was obtained for histological examination and RNA sequencing (RNA-Seq).

Results: Liver weight, plasma triglycerides (TG), alanine aminotransferase (ALT), and alanine aminotransferase (AST) levels of both ML groups were significantly lower than those of the WD group. On histological examination of the liver, the area of fatty deposits was found to be suppressed by ML administration. In the gene expression analysis of the liver of WD- versus ML-fed mice by RNA-Seq, 722/45,706 genes exhibited a significant change in expression (corrected p-value<0.05). Gene network analysis of these genes showed that genes related to liver inflammation were inactivated and those related to regeneration of liver were activated in the ML group.

Conclusion: ML functions to suppress HS in WD-fed mice and regulates genes related to inflammation and regeneration of liver cells.

Keywords: 1-deoxynojirimycin; Hepatic steatosis; RNA sequencing; flavonoids; inflammation.