The ULK1-NCOA3 axis restrains de novo lipogenesis and prevents diet-induced steatohepatitis and fibrosis in mice
Young Do Koo, Romilia Tatiana Castillo, Asha Sukumaran Nair, Michael Garneau, Chad Gochee, Zachary V. Campbell, Tashya Shreyas Vakil, Jua Ha, Alex Marti, Jamie Soto, Debajyoti Das, Nuria Martinez-Lopez, Shipra Sharma, Yennifer Delgado, Callie Phung, Immy A. Ashley, Edmund D. Kapelczak, Rashel Jacobo, Eric T. Weatherford, Dao-Fu Dai, Jihane N. Benhammou, Andrea G. Marshall, Antentor Hinton Jr., Ling Yang, Renata O. Pereira, Tara TeSlaa, Mehdi Bouhaddou, Rajat Singh, E. Dale Abel
Young Do Koo, Romilia Tatiana Castillo, Asha Sukumaran Nair, Michael Garneau, Chad Gochee, Zachary V. Campbell, Tashya Shreyas Vakil, Jua Ha, Alex Marti, Jamie Soto, Debajyoti Das, Nuria Martinez-Lopez, Shipra Sharma, Yennifer Delgado, Callie Phung, Immy A. Ashley, Edmund D. Kapelczak, Rashel Jacobo, Eric T. Weatherford, Dao-Fu Dai, Jihane N. Benhammou, Andrea G. Marshall, Antentor Hinton Jr., Ling Yang, Renata O. Pereira, Tara TeSlaa, Mehdi Bouhaddou, Rajat Singh, E. Dale Abel
View: Text | PDF
Research Article Cell biology Endocrinology Hepatology

The ULK1-NCOA3 axis restrains de novo lipogenesis and prevents diet-induced steatohepatitis and fibrosis in mice

Abstract

Metabolic dysfunction–associated steatotic liver disease (MASLD) and metabolic dysfunction–associated steatohepatitis (MASH) are leading causes of cirrhosis and hepatocellular carcinoma. Defects in autophagy contribute to the development of MASLD; however, the role of Unc-51–like autophagy-activating kinase 1 (ULK1) in the pathophysiology of MASLD remains unclear. Herein, we show that ULK1, a serine/threonine kinase and core autophagy protein, is significantly repressed in human MASH livers, and that hepatocyte-specific loss of ULK1 promotes, unexpectedly, hepatic steatosis and progression to liver fibrosis, without affecting basal autophagy flux. Phospho-proteomics identified the transcriptional coactivator NCOA3 as a downstream phospho-target of ULK1. Mechanistically, ULK1 phosphorylates NCOA3 to repress its transcriptional activity and restrain the CREB/CBP-mediated de novo lipogenic program. Accordingly, a phosphorylation-deficient NCOA3 mutant drives CREB/CBP-mediated lipogenesis, whereas genetic or pharmacological NCOA3 inhibition prevents steatosis, hepatic inflammation, and profibrotic signaling. Hence, ULK1-mediated NCOA3 phosphorylation is a fundamental and druggable checkpoint against the entire MASLD spectrum.

Authors

Young Do Koo, Romilia Tatiana Castillo, Asha Sukumaran Nair, Michael Garneau, Chad Gochee, Zachary V. Campbell, Tashya Shreyas Vakil, Jua Ha, Alex Marti, Jamie Soto, Debajyoti Das, Nuria Martinez-Lopez, Shipra Sharma, Yennifer Delgado, Callie Phung, Immy A. Ashley, Edmund D. Kapelczak, Rashel Jacobo, Eric T. Weatherford, Dao-Fu Dai, Jihane N. Benhammou, Andrea G. Marshall, Antentor Hinton Jr., Ling Yang, Renata O. Pereira, Tara TeSlaa, Mehdi Bouhaddou, Rajat Singh, E. Dale Abel

×

Figure 7

UKL1 deficiency represses NRF2 signaling and promotes oxidative stress and hepatic inflammation through NCOA3-dependent mechanisms.

Options: View larger image (or click on image) Download as PowerPoint
UKL1 deficiency represses NRF2 signaling and promotes oxidative stress a...
(A) Protein levels of NRF2 and Keap1 were examined in WT (n = 3), L-NCOA3KO (n = 3), L-ULK1KO (n = 3), and L-ULK1 KO × NCOA3 KO (DKO) (n = 3) after 12-weeks of NCD and HFD feeding. (B) ROS levels were determined in WT (n = 4), L-NCOA3KO (n = 4), L-ULK1KO (n = 4), and L-ULK1KO × NCOA3KO (n = 4) after 12-weeks of NCD and HFD feeding. (C) We intraperitoneally injected 18-week-old WT and L-ULK1 KO mice fed an NCD with PBS and SI-2 (5 mg/kg) twice a day for 10 days and protein levels of NRF2 and Keap1 were examined. (D) ROS levels were determined in the same mice described in (C). (E) mRNA levels of immune response–related genes in liver tissues of 18-week-old WT (n = 5–6) and L-ULK1 KO (n = 6–7) mice under NCD and HFD conditions, as in A. (F) qPCR was performed to measure RNA levels of immune response–related genes in liver tissues of 18-week-old NCD-fed WT (n = 4) and L-ULK1 KO (n = 4) mice after intraperitoneal injection with PBS and SI-2 (5 mg/kg) twice a day for 10 days. (G) Serum concentrations of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in WT (n = 3), L-NCOA3 KO (n = 3), L-ULK1 KO (n = 4), and L-ULK1KO × NCOA3KO (n = 3) mice under NCD and HFD conditions. (H) Schematic summarizing mechanisms linking ULK1 deficiency with the pathophysiology of hepatic steatosis and progression to MASH and fibrosis. All data represent the mean ± SEM. In A–G, data were analyzed by 2-way ANOVA to assess the effects of genotype and diet or treatment, followed by Tukey’s post hoc test. Actual P values are shown. See Supporting Data files for genotype × treatment interaction 2-way ANOVA statistics.