Combined small molecule and loss-of-function screen uncovers estrogen receptor alpha and CAD as host factors for HDV infection and antiviral targets

Gut. 2020 Jan;69(1):158-167. doi: 10.1136/gutjnl-2018-317065. Epub 2019 Mar 4.

Abstract

Objective: Hepatitis D virus (HDV) is a circular RNA virus coinfecting hepatocytes with hepatitis B virus. Chronic hepatitis D results in severe liver disease and an increased risk of liver cancer. Efficient therapeutic approaches against HDV are absent.

Design: Here, we combined an RNAi loss-of-function and small molecule screen to uncover host-dependency factors for HDV infection.

Results: Functional screening unravelled the hypoxia-inducible factor (HIF)-signalling and insulin-resistance pathways, RNA polymerase II, glycosaminoglycan biosynthesis and the pyrimidine metabolism as virus-hepatocyte dependency networks. Validation studies in primary human hepatocytes identified the carbamoyl-phosphatesynthetase 2, aspartate transcarbamylase and dihydroorotase (CAD) enzyme and estrogen receptor alpha (encoded by ESR1) as key host factors for HDV life cycle. Mechanistic studies revealed that the two host factors are required for viral replication. Inhibition studies using N-(phosphonoacetyl)-L-aspartic acid and fulvestrant, specific CAD and ESR1 inhibitors, respectively, uncovered their impact as antiviral targets.

Conclusion: The discovery of HDV host-dependency factors elucidates the pathogenesis of viral disease biology and opens therapeutic strategies for HDV cure.

Keywords: antiviral therapy; hepatitis D; liver; screening.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antiviral Agents / pharmacology
  • Aspartate Carbamoyltransferase / antagonists & inhibitors
  • Aspartate Carbamoyltransferase / genetics*
  • Aspartate Carbamoyltransferase / metabolism
  • Aspartic Acid / analogs & derivatives*
  • Aspartic Acid / pharmacology
  • Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) / antagonists & inhibitors
  • Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) / genetics*
  • Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) / metabolism
  • Cell Line
  • Dihydroorotase / antagonists & inhibitors
  • Dihydroorotase / genetics*
  • Dihydroorotase / metabolism
  • Estrogen Receptor Antagonists / pharmacology
  • Estrogen Receptor alpha / antagonists & inhibitors
  • Estrogen Receptor alpha / metabolism*
  • Fulvestrant / pharmacology*
  • Gene Silencing
  • Hepatitis D, Chronic / drug therapy*
  • Hepatitis D, Chronic / genetics
  • Hepatitis D, Chronic / metabolism
  • Hepatitis Delta Virus / physiology
  • Hepatocytes
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Insulin Resistance
  • Life Cycle Stages
  • Loss of Function Mutation
  • Phosphonoacetic Acid / analogs & derivatives*
  • Phosphonoacetic Acid / pharmacology
  • Pyrimidines / biosynthesis*
  • RNA Interference
  • RNA, Small Interfering / genetics
  • RNA, Viral / metabolism
  • Signal Transduction
  • Virus Replication

Substances

  • Antiviral Agents
  • CAD trifunctional enzyme
  • Estrogen Receptor Antagonists
  • Estrogen Receptor alpha
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Pyrimidines
  • RNA, Small Interfering
  • RNA, Viral
  • estrogen receptor alpha, human
  • Fulvestrant
  • Aspartic Acid
  • sparfosic acid
  • Aspartate Carbamoyltransferase
  • Dihydroorotase
  • Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing)
  • pyrimidine
  • Phosphonoacetic Acid