Impaired glycosylation promotes rapid transition to hepatocellular carcinoma in model of diet-induced steatotic liver disease
Abhishek K. Singh, Balkrishna Chaube, Kathryn M. Citrin, Joseph W.M. Fowler, Sungwoon Lee, Jonatas Catarino, James Knight, Sarah C. Lowery, Sonal Shree, Keira E. Mahoney, Nabil E. Boutagy, Inmaculada Ruz-Maldonado, Kathy Harry, Marya Shanabrough, Trenton T. Ross, Stacy A. Malaker, Yajaira Suárez, Carlos Fernández-Hernando, Kariona A. Grabińska, William C. Sessa
Abhishek K. Singh, Balkrishna Chaube, Kathryn M. Citrin, Joseph W.M. Fowler, Sungwoon Lee, Jonatas Catarino, James Knight, Sarah C. Lowery, Sonal Shree, Keira E. Mahoney, Nabil E. Boutagy, Inmaculada Ruz-Maldonado, Kathy Harry, Marya Shanabrough, Trenton T. Ross, Stacy A. Malaker, Yajaira Suárez, Carlos Fernández-Hernando, Kariona A. Grabińska, William C. Sessa
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Research Article Hepatology Metabolism Oncology

Impaired glycosylation promotes rapid transition to hepatocellular carcinoma in model of diet-induced steatotic liver disease

Abstract

Obesity-linked steatosis is a significant risk factor for hepatocellular carcinoma (HCC); however, the molecular mechanisms underlying the transition from metabolic dysfunction–associated steatotic liver disease (MASLD) to HCC remain unclear. Here, we explored the role of the ER-associated protein NgBR, an essential component of the cis-prenyltransferase (cis-PTase) enzyme, in chronic liver disease. Hepatocyte-specific NgBR deletion in mice (N-LKO) intensified triacylglycerol (TAG) accumulation, inflammatory responses, ER/oxidative stress, and fibrosis, ultimately resulting in HCC development with 100% penetrance after 4 months on a high-fat diet. Similarly, liver-specific knockout of DHDDS, NgBR’s cis-PTase partner, and a knockin model carrying a human NgBR mutation that impairs cis-PTase activity developed HCC under high-fat diet conditions, although with lower penetrance. A single-cell transcriptomic atlas from affected livers provides a detailed molecular analysis of the transition from liver pathophysiology to HCC development. Mechanistically, NgBR deficiency promoted excessive hepatic TAG accumulation by enhancing lipid uptake and impairing VLDL secretion. Importantly, pharmacological inhibition of diacylglycerol acyltransferase-2 (DGAT2), a key enzyme in TAG synthesis, abrogated diet-induced liver damage and HCC burden in N-LKO mice. Overall, our findings establish cis-PTase as a critical suppressor of MASLD-HCC conversion and suggest DGAT2 inhibition may serve as a promising therapeutic approach to delay HCC formation in advanced metabolic dysfunction–associated steatohepatitis.

Authors

Abhishek K. Singh, Balkrishna Chaube, Kathryn M. Citrin, Joseph W.M. Fowler, Sungwoon Lee, Jonatas Catarino, James Knight, Sarah C. Lowery, Sonal Shree, Keira E. Mahoney, Nabil E. Boutagy, Inmaculada Ruz-Maldonado, Kathy Harry, Marya Shanabrough, Trenton T. Ross, Stacy A. Malaker, Yajaira Suárez, Carlos Fernández-Hernando, Kariona A. Grabińska, William C. Sessa

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Figure 1

Loss of hepatic NgBR/Dhdds drives HCC development in diet-induced obesity, and reduced NgBR expression correlates with MASLD-MASH progression in human liver.

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Loss of hepatic NgBR/Dhdds drives HCC development in diet-induced obesit...
(A) Log2 normalized mRNA expression levels of NgBR (Nus1) in human liver samples with MASLD and various stages of MASH with different degrees of fibrosis. RNA-seq was performed on 15 healthy liver samples, 30 steatosis samples, and 20 MASH samples (F0–F4). Each data point represents a biological replicate. Statistical comparisons between control and liver disease conditions were conducted using limma’s decideTests with Benjamini-Hochberg correction. The adjusted P values are shown on the graph. In the box-and-whisker plots, the central lines represent medians, the edges of the box indicate upper and lower quartiles, and the whiskers indicate the minimum and maximum values. (B) Representative liver images from WT and N-LKO male mice fed an HFD or WD for 16 weeks, with arrowheads indicating HCC. Histological analysis of liver and tumor sections stained with H&E is shown on the right, and the graph summarizes HCC incidence in N-LKO and WT mice on HFD (n = 24) and WD (n = 16) (bottom). Original magnification, ×5. (C) IHC analysis of the proliferation marker Ki-67 in tumor and tumor-adjacent liver of N-LKO mice on WD for 16 weeks, with quantification of Ki-67/field (n = 3) shown at right. Original magnification, ×20. (D) Circulating AFP levels in WT (n = 5) and N-LKO (n = 6) mice fed HFD. (E) Schematic showing the generation of D-LKO mice. (1) The cassette is composed of a short flippase recombination enzyme (Flp) recognition target (FRT) and a Cre recombinase recognition target (loxP). Dhdds exons 2–3 are flanked by the loxP site. (2) Mice with floxed allele but missing neomycin cassette were generated by crossing with Flp recombinase deleter mice. (3) Afterward, these floxed mice were bred with mice expressing Cre recombinase to generate tissue-specific (D-LKO) mice. Genotyping from Dhddsfl/fl mice presentation bands from 1, both, or none of the floxed alleles. All data are presented as mean ± SEM. Statistical analysis: *P < 0.05 and ***P < 0.001, comparing N-LKO with WT mice using an unpaired 2-sided Welch’s t test.