Edgar N Tafaleng, Jie Li, Yan Wang, Tunda Hidvegi, Alex Soto-Gutierrez, Adam E Locke, Thomas J Nicholas, Yung-Chun Wang, Stephen Pak, Michael H Cho, Edwin K Silverman, Gary A Silverman, Sheng Chih Jin, Ira J Fox, David H Perlmutter
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引用次数: 0
Abstract
Background and aims: In the classical form of α1-antitrypsin deficiency, a misfolded variant α1-antitrypsin Z accumulates in the endoplasmic reticulum of liver cells and causes liver cell injury by gain-of-function proteotoxicity in a sub-group of affected homozygotes but relatively little is known about putative modifiers. Here, we carried out genomic sequencing in a uniquely affected family with an index case of liver failure and 2 homozygous siblings with minimal or no liver disease. Their sequences were compared to sequences in well-characterized cohorts of homozygotes with or without liver disease, and then candidate sequence variants were tested for changes in the kinetics of α1-antitrypsin variant Z degradation in iPS-derived hepatocyte-like cells derived from the affected siblings themselves.
Approach and results: Specific variants in autophagy genes MTMR12 and FAM134A could each accelerate the degradation of α1-antitrypsin variant Z in cells from the index patient, but both MTMR12 and FAM134A variants were needed to slow the degradation of α1-antitrypsin variant Z in cells from a protected sib, indicating that inheritance of both variants is needed to mediate the pathogenic effects of hepatic proteotoxicity at the cellular level. Analysis of homozygote cohorts showed that multiple patient-specific variants in proteostasis genes are likely to explain liver disease susceptibility at the population level.
Conclusions: These results validate the concept that genetic variation in autophagy function can determine susceptibility to liver disease in α1-antitrypsin deficiency and provide evidence that polygenic mechanisms and multiple patient-specific variants are likely needed for proteotoxic pathology.
期刊介绍:
HEPATOLOGY is recognized as the leading publication in the field of liver disease. It features original, peer-reviewed articles covering various aspects of liver structure, function, and disease. The journal's distinguished Editorial Board carefully selects the best articles each month, focusing on topics including immunology, chronic hepatitis, viral hepatitis, cirrhosis, genetic and metabolic liver diseases, liver cancer, and drug metabolism.