Loss of mARV1 Promotes CHOP Signaling in Mouse Liver

Author(s)

Shad Anthony Mitchell, Rowan University

Date Approved

7-2018

Document Type

Thesis

Degree Name

Master of Science in Molecular Pathology and Immunology

Department

Molecular Biology

College

Graduate School of Biomedical Sciences

Sponsor

Genesis Biotechnology Group

First Advisor

Salvatore Caradonna, PhD

Committee Member 1

Scott Gygax, PhD

Committee Member 2

Joseph Nickels, PhD

Subject(s)

Metabolic Syndrome, Non-alcoholic Fatty Liver Disease, Mice, Lipolysis, Liver, Metabolic Diseases, Fatty Acid Transport Proteins, Transcription Factor CHOP

Disciplines

Cell Biology | Cellular and Molecular Physiology | Endocrine System Diseases | Immunopathology | Laboratory and Basic Science Research | Medical Cell Biology | Medical Molecular Biology | Medicine and Health Sciences | Nutritional and Metabolic Diseases | Organismal Biological Physiology | Physiological Processes

Abstract

Metabolic syndrome (MetS) is a term used to define a set of metabolic diseases: obesity, type 2 diabetes (T2D), hyperlipidemia, hypertension, nonalcoholic fatty liver disease (NAFLD), and nonalcoholic hepatosteatosis (NASH). Those with MetS have a higher incidence of cardiovascular disease and stroke. Current drug treatments for MetS treat the individual pathologies associated with the diseases, rather than directly targeting MetS as a whole. We hypothesize that the inhibition of a ubiquitous lipid transporter known as ARV1 can improve pathologies associated with MetS. To test this hypothesis, we utilized liver tissue from mARV1 knockout mice fed a high-fat diet and examined whether loss of mARV1 results in a reduction in unfolded protein response signaling (UPR), a stress-activated pathway that precedes the chronic inflammation associated with NASH. During activation of this pathway, phosphorylation of the UPR kinase sensor, IRE1α, activates the transcription of genes involved in stress, including the gene, CHOP. Here, we found that loss of mARV1 caused a reduction in liver IRE1α phosphorylation but did not abolish CHOP transcription. These findings suggest that ARV1 inhibition activates certain branches of the UPR in a noncanonical manner. Interestingly, CHOP activation correlated with a decrease in serum triglycerides, an increase in high-density lipoprotein, and an increase in non-esterified free fatty acids in high fat-fed mARV1 knockout mice. Overall, our data strongly suggest that mARV1- knockout animals may be resistant to the initiation of hepatic apoptosis and NASH under high fat conditions and may undergo accelerated lipolysis when compared to wild-type animals.

Recommended Citation

Mitchell, Shad Anthony, "Loss of mARV1 Promotes CHOP Signaling in Mouse Liver" (2018). Graduate School of Biomedical Sciences Theses and Dissertations. 32.
https://rdw.rowan.edu/gsbs_etd/32