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
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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

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Figure 3

Hepatocyte-specific ULK1 deficiency drives lipogenesis, independent of insulin resistance.

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Hepatocyte-specific ULK1 deficiency drives lipogenesis, independent of i...
Relative (A) mRNA and (B) protein levels of lipogenic genes (SREBP1c, SCD1, and FAS) in liver tissues of WT (n = 4–5) and L-ULK1 KO (n = 4–5) mice under NCD and HFD conditions for 12-weeks. (C) Protein levels of lipogenesis regulators after silencing of ULK1 or other autophagy-related genes in hepa1c1c7 cells. (D) Volcano plot of RNA-Seq performed in 4-week-old WT and L-ULK1KO mice. (E and F) Protein levels of lipogenic regulators (E) and AKT phosphorylation (F) in liver tissues of 4-week-old WT (n = 5) and L-ULK1 KO (n = 5) mice. (G) Fractional labeling, concentration, and flux turnover of C16:0 palmitic acid in WT and liver-specific ULK1 KO mice at 4 weeks of age (n = 6–8/group). KO livers displayed a trend toward increased labeling and flux turnover. All data represent the mean ± SEM. In E and G, data were analyzed by 2-tailed Student’s t test; in C, 1-way ANOVA was used. Data in A, B, and F were analyzed by 2-way ANOVA to assess the effects of genotype and diet, followed by Tukey’s post hoc test for multiple comparisons; actual P values are shown. See Supporting Data files for genotype × treatment interaction 2-way ANOVA statistics.