Lipid droplet screen in human hepatocytes identifies TRRAP as a regulator of cellular triglyceride metabolism

Clin Transl Sci. 2021 Jul;14(4):1369-1379. doi: 10.1111/cts.12988. Epub 2021 Jun 22.

Abstract

Hepatocytes store triglycerides (TGs) in the form of lipid droplets (LDs), which are increased in hepatosteatosis. The regulation of hepatic LDs is poorly understood and new therapies to reduce hepatosteatosis are needed. We performed a siRNA kinase and phosphatase screen in HuH-7 cells using high-content automated imaging of LDs. Changes in accumulated lipids were quantified with developed pipeline that measures intensity, area, and number of LDs. Selected "hits," which reduced lipid accumulation, were further validated with other lipid and expression assays. Among several siRNAs that resulted in significantly reduced LDs, one was targeted to the nuclear adapter protein, transformation/transcription domain-associated protein (TRRAP). Knockdown of TRRAP reduced triglyceride accumulation in HuH-7 hepatocytes, in part by reducing C/EBPα-mediated de novo synthesis of TGs. These findings implicate TRRAP as a novel regulator of hepatic TG metabolism and nominate it as a potential drug target for hepatosteatosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / analysis
  • Adaptor Proteins, Signal Transducing / antagonists & inhibitors
  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Cell Line, Tumor
  • Fatty Liver / drug therapy
  • Fatty Liver / metabolism
  • Fatty Liver / pathology
  • Gene Knockdown Techniques
  • Hepatocytes / metabolism*
  • High-Throughput Screening Assays
  • Humans
  • Lipid Droplets / metabolism
  • Lipid Metabolism*
  • Nuclear Proteins / analysis
  • Nuclear Proteins / antagonists & inhibitors
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Triglycerides / analysis
  • Triglycerides / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • Nuclear Proteins
  • Triglycerides
  • transformation-transcription domain-associated protein