The endocannabinoid system promotes hepatocyte progenitor cell proliferation and maturation by modulating cellular energetics

Bani Mukhopadhyay; Kellie Holovac; Kornel Schuebel; Partha Mukhopadhyay; Resat Cinar; Sindhu Iyer; Cheryl Marietta; David Goldman; George Kunos

doi:10.1038/s41420-023-01400-6

The endocannabinoid system promotes hepatocyte progenitor cell proliferation and maturation by modulating cellular energetics

Cell Death Discov. 2023 Mar 25;9(1):104. doi: 10.1038/s41420-023-01400-6.

Authors

Bani Mukhopadhyay^{1

2}, Kellie Holovac³, Kornel Schuebel⁴, Partha Mukhopadhyay⁵, Resat Cinar³, Sindhu Iyer³, Cheryl Marietta⁴, David Goldman⁴, George Kunos³

Affiliations

¹ Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA. [email protected].
² Laboratory of Neurogenetics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA. [email protected].
³ Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA.
⁴ Laboratory of Neurogenetics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA.
⁵ Laboratory of Cardiovascular Physiology and Tissue Injury, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA.

Abstract

The proliferation and differentiation of hepatic progenitor cells (HPCs) drive the homeostatic renewal of the liver under diverse conditions. Liver regeneration is associated with an increase in Axin2⁺Cnr1⁺ HPCs, along with a marked increase in the levels of the endocannabinoid anandamide (AEA). But the molecular mechanism linking AEA signaling to HPC proliferation and/or differentiation has not been explored. Here, we show that in vitro exposure of HPCs to AEA triggers both cell cycling and differentiation along with increased expression of Cnr1, Krt19, and Axin2. Mechanistically, we found that AEA promotes the nuclear localization of the transcription factor β-catenin, with subsequent induction of its downstream targets. Systemic analyses of cells after CRISPR-mediated knockout of the β-catenin-regulated transcriptome revealed that AEA modulates β-catenin-dependent cell cycling and differentiation, as well as interleukin pathways. Further, we found that AEA promotes OXPHOS in HPCs when amino acids and glucose are readily available as substrates, but AEA inhibits it when the cells rely primarily on fatty acid oxidation. Thus, the endocannabinoid system promotes hepatocyte renewal and maturation by stimulating the proliferation of Axin2⁺Cnr1⁺ HPCs via the β-catenin pathways while modulating the metabolic activity of their precursor cells.