Liver organoids reproduce alpha-1 antitrypsin deficiency-related liver disease

Abstract

Background and aims Alpha-1 antitrypsin (AAT) is a product of SERPINA1 gene mainly expressed by hepatocytes. Clinically relevant mutations in the SERPINA1 gene, such as Z (Glu342Lys), results in an expression of misfolded AAT protein having high propensity to polymerize, accumulate in hepatocytes and thus to enhance a risk for hepatocyte damage and subsequent liver disease. So far, the relationship between the Z-AAT accumulation and liver cell damage remains not completely understood. We present three-dimensional organoid culture systems, as a novel tool for modeling Z-AAT-related liver diseases. Methods We have established liver organoids from liver biopsies of patients with homozygous (ZZ) and heterozygous (MZ) deficiency and normal (MM) genotypes of AAT. The features of these organoid models were characterized by analyzing AAT protein secretion and intracellular aggregation in MZ and ZZ genotypes as well as SERPINA1 expression in differentiated cultures. Results Transcriptional analysis of differentiated organoid cultures by RNA-Seq showed hepatocyte-specific gene expression profile. Genes, such as ALB, APOB, CYP3A4 and SERPINA1, were validated and confirmed through quantitative-PCR analysis. The organoids from MZ and ZZ cases showed intracellular aggregation and lower secretion of AAT protein, and lower expression of ALB and APOB, as typically seen in hepatocytes from Z-AAT deficiency patients. Furthermore, organoids responded to external stimulus. Treatment with oncostatin M, a well-known inducer of SERPINA1, increased expression of the full-length transcripts (AAT-1C) as well as the short transcript of AAT (AAT-ST1C4). Conclusions Liver organoid model recapitulates the key features of Z-AAT deficiency and provides a useful tool for disease modeling.

SARS-CoV-2 mutation 614G creates an elastase cleavage site enhancing its spread in high AAT-deficient regions

“…Thus, the prevalence of AAT deficiency varies among populations ( Burrows et al, 2000 ; Dau et al, 2015 ; Borel et al, 2018 ) in proportion to the population frequencies of the alleles S and Z. The primary role of circulating AAT, which is synthesized in the liver ( Gómez-Mariano et al, 2020 ), is to protect the lung tissue against damage by neutrophil elastase ( Dau et al, 2015 ; Strnad et al, 2020 ). Some of the AAT deficient genotypes (e.g., S-Z: [SS, SZ and ZZ]) are susceptible to COPD ( Dahl et al, 2005 ).…”

Organoids to model liver disease

“… 24 In addition, a recent study reported the use of liver organoids derived from patients with different A1AT deficiency-causing genotypes. 51 Remarkably, liver organoids reflect genotype-specific features observed in patients and provide a new system for validating mutations in rare genetic diseases.…”

A Perfusion Bioreactor for Longitudinal Monitoring of Bioengineered Liver Constructs

“…Transcription levels for hepatocyte nuclear factor 4-α ( HNF4α ), UDP-glucuronosyl- transferasy1-1 ( UGTA1 ), SERPINA1 , forkhead box A2 ( FOXA2 ), cytochrome P450 family 1 subfamily A member 2 and family 3 subfamily A member 4 ( CYP1A2 and CYP3A4 ) and MKI67 were analysed using HPRT1 as reference gene and normalising gene expression on Luc + HepG2 cells cultured in conventional 2D culture conditions ( Figure 5 h,i). The SERPINA1 gene, which encodes for hepatocyte’s serine protease inhibitor α-1-antitrypsin [ 11 , 12 ] resulted to be significantly upregulated in bioreactor cultures compared to static culture conditions and 2D cultured cells. Luc + HepG2 3D cultured in the bioreactor showed upregulation of HNF4α in respect to conventional 2D cultures.…”