IGFBP-3 mediates metabolic homeostasis during hyperosmolar stress in the corneal epithelium

Evan D. Bogdan, Whitney L. Stuard, Rossella Titone, Danielle M. Robertson

Research output: Contribution to journalArticlepeer-review

Abstract

PURPOSE. The insulin-like growth factor binding protein-3 (IGFBP-3) is a multifunctional secretory protein with well-known roles in cell growth and survival. Data in our laboratory suggest that IGFBP-3 may be functioning as a stress response protein in the corneal epithelium. The purpose of this study is to determine the role of IGFBP-3 in mediating the corneal epithelial cell stress response to hyperosmolarity, a well-known pathophysiological event in the development of dry eye disease. METHODS. Telomerase-immortalized human corneal epithelial (hTCEpi) cells were used in this study. Cells were cultured in serum-free media with (growth) or without (basal) supplements. Hyperosmolarity was achieved by increasing salt concentrations to 450 and 500 mOsM. Metabolic and mitochondrial changes were assessed using Seahorse metabolic flux analysis and assays for mitochondrial calcium, polarization and mtDNA. Levels of IGFBP-3 and inflammatory mediators were quantified using ELISA. Cytotoxicity was evaluated using a lactate dehydrogenase assay. In select experiments, cells were cotreated with 500 ng/mL recombinant human (rh)IGFBP-3. RESULTS. Hyperosmolar stress altered metabolic activity, shifting cells towards a respiratory phenotype. Hyperosmolar stress further altered mitochondrial calcium levels, depolarized mitochondria, decreased levels of ATP, mtDNA, and expression of IGFBP-3. In contrast, hyperosmolar stress increased production of the proinflammatory cytokines IL-6 and IL-8. Supplementation with rhIGFBP-3 abrogated metabolic and mitochondrial changes with only marginal effects on IL-8. CONCLUSIONS. These findings indicate that IGFBP-3 is a critical protein involved in hyperosmolar stress responses in the corneal epithelium. These data further support a new role for IGFBP-3 in the control of cellular metabolism.

Original languageEnglish (US)
Article number11
JournalInvestigative Ophthalmology and Visual Science
Volume62
Issue number7
DOIs
StatePublished - Jun 2021

Keywords

  • Corneal epithelial cells
  • Glycolysis
  • Hyperosmolarity
  • Inflammation
  • Mitochondria
  • Respiration

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Fingerprint

Dive into the research topics of 'IGFBP-3 mediates metabolic homeostasis during hyperosmolar stress in the corneal epithelium'. Together they form a unique fingerprint.

Cite this