Cellular crosstalk mediated by platelet-derived growth factor BB and transforming growth factor β during hepatic injury activates hepatic stellate cells

Sowmya Mekala, Subba Rao V. Tulimilli, Ramasatyaveni Geesala, Kanakaraju Manupati, Neha R. Dhoke, Amitava Das

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Apoptotic hepatocytes release factors that activate hepatic stellate cells (HSCs), thereby inducing hepatic fibrosis. In the present study, in vivo and in vitro injury models were established using acetaminophen, ethanol, carbon tetrachloride, or thioacetamide. Histology of hepatotoxicant-induced diseased hepatic tissue correlated with differential expression of fibrosis-related genes. A marked increase in co-staining of transforming growth factor β receptor type II (TGFRIIβ) – desmin or α-smooth muscle actin – platelet-derived growth factor receptor β (PDGFRβ), markers of activated HSCs, in liver sections of these hepatotoxicant-treated mice also depicted an increase in Annexin V – cytokeratin expressing hepatocytes. To understand the molecular mechanisms of disease pathology, in vitro experiments were designed using the conditioned medium (CM) of hepatotoxicant-treated HepG2 cells supplemented to HSCs. A significant increase in HSC proliferation, migration, and expression of fibrosis-related genes and protein was observed, thereby suggesting the characteristics of an activated phenotype. Treating HepG2 cells with hepatotoxicants resulted in a significant increase in mRNA expression of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor β (TGFβ). CM supplemented to HSCs resulted in increased phosphorylation of PDGFRβ and TGFRIIβ along with its downstream effectors, extracellular signal-related kinase 1/2 and focal adhesion kinase. Neutralizing antibodies against PDGF-BB and TGFβ effectively perturbed the hepatotoxicant-treated HepG2 cell CM-induced activation of HSCs. This study suggests PDGF-BB and TGFβ as potential molecular targets for developing anti-fibrotic therapeutics.

Original languageEnglish (US)
Pages (from-to)728-741
Number of pages14
JournalCanadian journal of physiology and pharmacology
Volume96
Issue number8
DOIs
StatePublished - 2018
Externally publishedYes

Keywords

  • Acetaminophen
  • Carbon tetrachloride
  • Ethanol
  • Hepatic stellate cell activation
  • Liver fibrosis
  • Neutralizing antibodies
  • Platelet-derived growth factor BB
  • Thioacetamide
  • Transforming growth factor β

ASJC Scopus subject areas

  • Physiology
  • Pharmacology
  • Physiology (medical)

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