| Title: | mARC1 in MASLD: Modulation of lipid accumulation in human hepatocytes and adipocytes |
| Journal: | Hepatology Communications |
| Published: | 12 Apr 2024 |
| Pubmed: | https://pubmed.ncbi.nlm.nih.gov/38619429/ |
| DOI: | https://doi.org/10.1097/hc9.0000000000000365 |
Publication 9913
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Abstract
BACKGROUND: Mutations in the gene MTARC1 (mitochondrial amidoxime-reducing component 1) protect carriers from metabolic dysfunction-associated steatohepatitis (MASH) and cirrhosis. MTARC1 encodes the mARC1 enzyme, which is localized to the mitochondria and has no known MASH-relevant molecular function. Our studies aimed to expand on the published human genetic mARC1 data and to observe the molecular effects of mARC1 modulation in preclinical MASH models.</p>
METHODS AND RESULTS: We identified a novel human structural variant deletion in MTARC1, which is associated with various biomarkers of liver health, including alanine aminotransferase levels. Phenome-wide Mendelian Randomization analyses additionally identified novel putatively causal associations between MTARC1 expression, and esophageal varices and cardiorespiratory traits. We observed that protective MTARC1 variants decreased protein accumulation in in vitro overexpression systems and used genetic tools to study mARC1 depletion in relevant human and mouse systems. Hepatocyte mARC1 knockdown in murine MASH models reduced body weight, liver steatosis, oxidative stress, cell death, and fibrogenesis markers. mARC1 siRNA treatment and overexpression modulated lipid accumulation and cell death consistently in primary human hepatocytes, hepatocyte cell lines, and primary human adipocytes. mARC1 depletion affected the accumulation of distinct lipid species and the expression of inflammatory and mitochondrial pathway genes/proteins in both in vitro and in vivo models.</p>
CONCLUSIONS: Depleting hepatocyte mARC1 improved metabolic dysfunction-associated steatotic liver disease-related outcomes. Given the functional role of mARC1 in human adipocyte lipid accumulation, systemic targeting of mARC1 should be considered when designing mARC1 therapies. Our data point to plasma lipid biomarkers predictive of mARC1 abundance, such as Ceramide 22:1. We propose future areas of study to describe the precise molecular function of mARC1, including lipid trafficking and subcellular location within or around the mitochondria and endoplasmic reticulum.</p>
37 Authors
- Amanda K. Jones
- Besnik Bajrami
- Morgan K. Campbell
- Abdullah Mesut Erzurumluoglu
- Qiusha Guo
- Hongxing Chen
- Xiaomei Zhang
- Svetlana Zeveleva
- David Kvaskoff
- Andreas-David Brunner
- Stefanie Muller
- Vasudha Gathey
- Rajvee M. Dave
- James W. Tanner
- Sophia Rixen
- Michel A. Struwe
- Kathryn Phoenix
- Kaitlyn J. Klumph
- Heather Robinson
- Daniel Veyel
- Annkatrin Muller
- Boris Noyvert
- Boris Alexander Bartholdy
- Agnes A. Steixner-Kumar
- Jan Stutzki
- Dmitriy Drichel
- Steffen Omland
- Ryan Sheehan
- Jon Hill
- Tom Bretschneider
- Dirk Gottschling
- Axel J. Scheidig
- Bernd Clement
- Martin Giera
- Zhihao Ding
- John Broadwater
- Curtis R. Warren
1 Application
| Application ID | Title |
|---|---|
| 57952 | Supporting the discovery and evaluation of drug targets and biomarkers for therapeutic areas that are in scope of Boehringer Ingelheim's R&D through analyses of UK Biobank data |
Enabling scientific discoveries that improve human health