No evidence for an increased liver uptake of SARS-CoV-2 in metabolic-associated fatty liver disease
Authors: Louise Biquard, Dominique Valla, Pierre-Emmanuel Rautou
Journal: Journal of Hepatology (2020)

Non-alcoholic fatty liver diseases in patients with COVID-19: A retrospective studyJournal of HepatologyVol. 73Issue 2PreviewLiver injury has been observed in patients with COVID-19, at an incidence ranging from 14–53%.1–3 We examined the liver injury patterns and implication of non-alcoholic fatty liver diseases (NAFLD) on clinical outcomes in Chinese patients with COVID-19. Full-Text PDF Reply to: 'No evidence for an increased liver uptake of SARS-CoV-2 in metabolic-associated fatty liver disease'Journal of HepatologyVol. 73Issue 3PreviewWe read with interest the letter by Biquard et al.1 In their study, mRNA expression of SARS-CoV-2 infection critical genes, such as angiotensin-converting enzyme 2 (ACE2), transmembrane protease serine 2 (TMPRSS2), phosphatidylinositol 3-phosphate 5-kinase (PIKFYVE) and cathepsin L were found not to be enhanced in patients with metabolic-associated fatty liver disease (MAFLD, previously called non-alcoholic fatty liver disease [NAFLD]) or obesity. This finding is of potential added value to our observation that patients with COVID-19 had worse outcomes if they had underlying MAFLD. Full-Text PDF Obese patients with NASH have increased hepatic expression of SARS-CoV-2 critical entry pointsJournal of HepatologyVol. 74Issue 2PreviewWe read with great interest the article published by Biquard and colleagues showing that, according to public transcriptomic data, the hepatic expression of angiotensin converting enzyme 2 (ACE2) and the cellular transmembrane protease serine 2 (TMPRSS2) remains unchanged in patients with metabolic-associated fatty liver disease (MAFLD).1 SARS-CoV-2 attaches to cells by binding to its receptor ACE2. TMPRSS2 then cleaves the SARS-CoV-2 spike protein, allowing fusion of cellular and viral membranes. Full-Text PDF We read with interest the research article published by Ji and colleagues, in the Journal of Hepatology, showing that patients with metabolic-associated fatty liver disease (MAFLD) have a higher risk of COVID-19 disease progression and higher likelihood of abnormal liver blood tests from admission to discharge than patients without MAFLD.1Ji D. Qin E. Xu J. Zhang D. Cheng G. Wang Y. et al.Non-alcoholic fatty liver diseases in patients with COVID-19: A retrospective study.J Hepatol. 2020; 73: 451-453Abstract Full Text Full Text PDF PubMed Scopus (392) Google Scholar Given the absence of data on medical history of these patients, this persistence of liver blood test abnormalities could be either a mere reflection of pre-existing abnormalities related to MAFLD or could alternatively be due to a higher susceptibility of the fatty liver to SARS-CoV-2 infection. We therefore investigated whether MAFLD is associated with altered liver expression of SARS-CoV-2 critical entry proteins. SARS-CoV-2 attaches to cells by binding to angiotensin-converting enzyme 2 (ACE2). The cellular protease transmembrane protease serine 2 (TMPRSS2) cleaves the SARS-CoV-2 spike protein, allowing fusion of cellular and viral membranes.2Hoffmann M. Kleine-Weber H. Schroeder S. Krüger N. Herrler T. Erichsen S. et al.SARS-CoV-2 cell entry depends on ACE2 and TMPRSS2 and is blocked by a clinically proven protease inhibitor.Cell. 2020; 181: 271-280.e8Abstract Full Text Full Text PDF PubMed Scopus (13652) Google Scholar,3Zhou P. Yang X. Wang X. Hu B. Zhang L. Zhang W. et al.A pneumonia outbreak associated with a new coronavirus of probable bat origin.Nature. 2020; 579: 270-273Crossref PubMed Scopus (14584) Google Scholar Moreover, in the HEK293 cell line, overexpressing human ACE2, SARS-CoV-2 enters through endocytosis with critical roles played by endocytosis-regulating protein phosphatidylinositol 3-phosphate 5-kinase (PIKFYVE).4Ou X. Liu Y. Lei X. Li P. Mi D. Ren L. et al.Characterization of spike glycoprotein of SARS-CoV-2 on virus entry and its immune cross-reactivity with SARS-CoV.Nat Commun. 2020; 11: 1620Crossref PubMed Scopus (2253) Google Scholar Finally, as described for SARS-CoV and MERS-CoV, cathepsin L is also critical for priming of the SARS-CoV-2 spike protein in lysosomes following entry through endocytosis.4Ou X. Liu Y. Lei X. Li P. Mi D. Ren L. et al.Characterization of spike glycoprotein of SARS-CoV-2 on virus entry and its immune cross-reactivity with SARS-CoV.Nat Commun. 2020; 11: 1620Crossref PubMed Scopus (2253) Google Scholar We analysed the influence of MAFLD on liver gene expression of these 4 proteins implicated in SARS-CoV-2 infection by analysing public data from patients and from mice with MAFLD. In 2013, Ahrens and colleagues published microarray data obtained on human liver biopsies.5Ahrens M. Ammerpohl O. von Schönfels W. Kolarova J. Bens S. Itzel T. et al.DNA methylation analysis in nonalcoholic fatty liver disease suggests distinct disease-specific and remodeling signatures after bariatric surgery.Cell Metab. 2013; 18: 296-302Abstract Full Text Full Text PDF PubMed Scopus (385) Google Scholar,6Jochen H. Andreas T. Timo I. Human liver biopsy of different phases from control to NASH, access number GSE48452. GEO Dataset.https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE48452Date: 2013Google Scholar They made available transcriptomic data from 12 lean patients without MAFLD, 16 obese patients without MAFLD, 9 patients with simple steatosis and 17 patients with biopsy proven non-alcoholic steatohepatitis (NASH). Using these datasets, we observed that none of the genes necessary for SARS-CoV-2 infection was differentially expressed between lean or obese controls and patients with simple steatosis or with NASH (Table 1).Table 1mRNA expression of SARS-CoV-2 infection critical genes in human liver biopsy.Gene nameLean without MAFLD (n = 12) vs. NASH (n = 17)Lean without MAFLD (n = 12) vs. simple steatosis (n = 9)Obese without MAFLD (n = 16) vs. simple steatosis (n = 9)Obese without MAFLD (n = 16) vs. NASH (n = 17)Lean and obese without MAFLD (n = 28) vs. simple steatosis or NASH (n = 26)Fold-changeadj. p valueFold-changeadj. p valueFold-changeadj. p valueFold-changeadj. p valueFold-changeadj. p valueACE21.410.391.000.990.990.971.390.141.240.24CTSL0.980.961.100.691.040.730.920.670.990.95TMPRSS20.850.720.780.570.870.640.940.950.880.60PIKFYVE1.030.930.770.940.850.110.920.640.940.53Human microarray data6Jochen H. Andreas T. Timo I. Human liver biopsy of different phases from control to NASH, access number GSE48452. GEO Dataset.https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE48452Date: 2013Google Scholar was made available by Ahrens and colleagues5Ahrens M. Ammerpohl O. von Schönfels W. Kolarova J. Bens S. Itzel T. et al.DNA methylation analysis in nonalcoholic fatty liver disease suggests distinct disease-specific and remodeling signatures after bariatric surgery.Cell Metab. 2013; 18: 296-302Abstract Full Text Full Text PDF PubMed Scopus (385) Google Scholar and reanalysed by us using Geo2R8Xiong X. Wang Q. Wang S. Zhang J. Liu T. Guo L. et al.Mapping the molecular signatures of diet-induced NASH and its regulation by the hepatokine Tsukushi.Mol Metab. 2019; 20: 128-137Crossref PubMed Scopus (71) Google Scholar default settings. Geo2R is based on the "Linear Models for Microarray Data" R package that computes a moderated t-statistic for each gene and corresponding p value. Adjustment for multiple testing was performed using Benjamini and Hochberg's correction. CSTL gene encodes cathepsin L protein. Human transcriptomics data is available on GEO Dataset under the accession number GSE48452.MAFLD, metabolic-associated fatty liver disease; NASH, non-alcoholic steatohepatitis. Open table in a new tab Human microarray data6Jochen H. Andreas T. Timo I. Human liver biopsy of different phases from control to NASH, access number GSE48452. GEO Dataset.https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE48452Date: 2013Google Scholar was made available by Ahrens and colleagues5Ahrens M. Ammerpohl O. von Schönfels W. Kolarova J. Bens S. Itzel T. et al.DNA methylation analysis in nonalcoholic fatty liver disease suggests distinct disease-specific and remodeling signatures after bariatric surgery.Cell Metab. 2013; 18: 296-302Abstract Full Text Full Text PDF PubMed Scopus (385) Google Scholar and reanalysed by us using Geo2R8Xiong X. Wang Q. Wang S. Zhang J. Liu T. Guo L. et al.Mapping the molecular signatures of diet-induced NASH and its regulation by the hepatokine Tsukushi.Mol Metab. 2019; 20: 128-137Crossref PubMed Scopus (71) Google Scholar default settings. Geo2R is based on the "Linear Models for Microarray Data" R package that computes a moderated t-statistic for each gene and corresponding p value. Adjustment for multiple testing was performed using Benjamini and Hochberg's correction. CSTL gene encodes cathepsin L protein. Human transcriptomics data is available on GEO Dataset under the accession number GSE48452. MAFLD, metabolic-associated fatty liver disease; NASH, non-alcoholic steatohepatitis. We performed the same analysis in a mouse dataset published by Xiong and colleagues.7Barrett T. Wilhite S. Ledoux P. Evangelista C. Kim I. Tomashevsky M. et al.NCBI GEO: archive for functional genomics data sets—update.Nucleic Acids Res. 2013; 41: D991-D995Crossref PubMed Scopus (6431) Google Scholar Similarly, we observed no increase in liver gene expression of the 4 proteins implicated in SARS-CoV-2 infection between MAFLD mice and control mice (data not shown). In conclusion, MAFLD is not associated with changes in liver expression of genes implicated in SARS-CoV-2 infection. The observed persistence of liver blood test abnormalities reported by Ji and colleagues is thus likely not explained by increased hepatic SARS-CoV-2 uptake. This work was supported by the "Institut National de la Santé et de la Recherche Médicale" (ATIP AVENIR), the "Agence Nationale pour la Recherche" (ANR-18-CE14-0006-01, RHU QUID-NASH) and by "Émergence, Ville de Paris". L.B. performed the bioinformatic analysis; L.B. and P.E.R. wrote the manuscript; D.V. provided guidance and proof-read the manuscript; all authors revised and approved the final version. The authors declare no conflict of interest. Please refer to the accompanying ICMJE disclosure forms for further details. Download .pdf (21.29 MB) Help with pdf files disclosures.pdf