TM4SF5-mediated CD44v8-10 splicing variant promotes survival of type II alveolar epithelial cells during idiopathic pulmonary fibrosis

Cell Death Dis. 2019 Sep 9;10(9):645. doi: 10.1038/s41419-019-1878-5.

Abstract

Reactive oxygen species (ROS) regulate cell fate, although signaling molecules that regulate ROS hormesis remain unclear. Here we show that transmembrane 4 L six family member 5 (TM4SF5) in lung epithelial cells induced the alternatively spliced CD44v8-10 variant via an inverse ZEB2/epithelial splicing regulatory proteins (ESRPs) linkage. TM4SF5 formed complexes with the cystine/glutamate antiporter system via TM4SF5- and CD44v8-10-dependent CD98hc plasma-membrane enrichment. Dynamic TM4SF5 binding to CD98hc required CD44v8-10 under ROS-generating inflammatory conditions. TM4SF5 and CD44v8-10 upregulated cystine/glutamate antiporter activity and intracellular glutathione levels, leading to ROS modulation for cell survival. Tm4sf5-null mice exhibited attenuated bleomycin-induced pulmonary fibrosis with lower CD44v8-10 and ESRPs levels than wild-type mice. Primary mouse alveolar epithelial cells (AECs) revealed type II AECs (AECII), but not type I, to adapt the TM4SF5-mediated characteristics, suggesting TM4SF5-mediated AECII survival following AECI injury during idiopathic pulmonary fibrosis (IPF). Thus, the TM4SF5-mediated CD44v8-10 splice variant could be targeted against IPF.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Alveolar Epithelial Cells / metabolism*
  • Alveolar Epithelial Cells / pathology
  • Animals
  • Cell Line, Tumor
  • Cell Survival / physiology
  • Humans
  • Hyaluronan Receptors / genetics
  • Hyaluronan Receptors / metabolism*
  • Male
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Pulmonary Fibrosis / genetics
  • Pulmonary Fibrosis / metabolism*
  • Pulmonary Fibrosis / pathology
  • RNA Splicing
  • Reactive Oxygen Species / metabolism

Substances

  • CD44 protein, human
  • Cd44 protein, mouse
  • Hyaluronan Receptors
  • Membrane Proteins
  • Reactive Oxygen Species
  • TM4SF5 protein, human
  • TM4SF5 protein, mouse