CB1R regulates soluble leptin receptor levels via CHOP, contributing to hepatic leptin resistance
- The Hebrew University of Jerusalem, Israel
- National Institute on Alcohol Abuse & Alcoholism, United States
- Semmelweis University, Hungary
- Hebrew University of Jerusalem, Israel
Abstract
The soluble isoform of leptin receptor (sOb-R), secreted by the liver, regulates leptin bioavailability and bioactivity. Its reduced levels in diet-induced obesity (DIO) contribute to hyperleptinemia and leptin resistance, effects that are regulated by the endocannabinoid (eCB)/CB1R system. Here we show that pharmacological activation/blockade and genetic overexpression/deletion of hepatic CB1R modulates sOb-R levels and hepatic leptin resistance. Interestingly, peripheral CB1R blockade failed to reverse DIO-induced reduction of sOb-R levels, increased fat mass and dyslipidemia, and hepatic steatosis in mice lacking C/EBP homologous protein (CHOP), whereas direct activation of CB1R in wild-type hepatocytes reduced sOb-R levels in a CHOP-dependent manner. Moreover, CHOP stimulation increased sOb-R expression and release via a direct regulation of its promoter, while CHOP deletion reduced leptin sensitivity. Our findings highlight a novel molecular aspect by which the hepatic eCB/CB1R system is involved in the development of hepatic leptin resistance and in the regulation of sOb-R levels via CHOP.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for all figures.
Article and author information
Author details
Funding
Israel Science Foundation (617/14)
- Joseph Tam
Israel Science Foundation (158/18)
- Joseph Tam
The Obesity Society's Early Career Research Award
- Joseph Tam
ERC-2015-StG grant (676841)
- Joseph Tam
Hungarian National Research, Development, and Innovation Office (NKFI-6/FK_124038)
- Gergő Szanda
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All animal studies were approved by the Institutional Animal Care and Use Committee of the Hebrew University of Jerusalem (AAALAC accreditation #1285; Ethic approval numbers MD-14-14008 & MD-19-15951). Animal studies are reported in compliance with the ARRIVE guidelines (Kilkenny et al., 2010), and are based on the rule of the replacement, refinement, or reduction. All the animals used in this study were housed under specific pathogen‐free (SPF) conditions, up to five per cage, in standard plastic cages with natural soft sawdust as bedding. The animals were maintained under controlled temperature of 22-24{degree sign}C, humidity at 55 {plus minus} 5%, and alternating 12-hour light/dark cycles (lights were on between 7:00 and 19:00 hr), and provided with food and water ad libitum.
Copyright
© 2020, Drori et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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CB1R regulates soluble leptin receptor levels via CHOP, contributing to hepatic leptin resistance
eLife 9:e60771.
https://doi.org/10.7554/eLife.60771
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