Intestinal epithelial tight junction barrier regulation by autophagy-related protein ATG6/beclin 1

Morgan Wong, Ashwinkumar Subramenium Ganapathy, Eric Suchanec, Laura Laidler, Thomas Ma, Prashant Nighot

Research output: Contribution to journalArticle

Abstract

A defective tight junction (TJ) barrier is a key pathogenic factor for inflammatory bowel disease. Previously, we have shown that autophagy, a cell survival mechanism, enhances intestinal epithelial TJ barrier function. Autophagy-related protein-6 (ATG6/beclin 1), a key protein in the autophagy pathway, also plays a role in the endocytic pathway. The constitutive role of beclin 1 in the intestinal TJ barrier is not known. In Caco-2 cells, beclin 1 was found to be coimmunoprecipitated with the TJ protein occludin and colocalized with occludin on the membrane. Treatment of Caco-2 cells with beclin 1 peptide [transactivating regulatory protein (Tat)-beclin 1] reduced TJ barrier function. Activation of beclin 1 increased occludin endocytosis and reduced total occludin protein level. In contrast, beclin 1 siRNA transfection enhanced Caco-2 TJ barrier function. In pharmacologic and genetic autophagy inhibition studies, the constitutive function of beclin 1 in the TJ barrier was found to be autophagy independent. However, de novo induction of autophagy with starvation or rapamycin prevented Tat-beclin 1-induced increase in TJ permeability and reduction in occludin level. Induction of autophagy also resulted in reduced beclin 1-occludin association. In mouse colon, beclin 1 colocalized with occludin on the epithelial membrane. Perfusion of mouse colon with beclin 1 peptide caused an increase in colonic TJ permeability that was prevented by in vivo induction of autophagy. These findings show that beclin 1 plays a constitutive, autophagy-independent role in the regulation of intestinal TJ barrier function via endocytosis of occludin. Autophagy terminates constitutive beclin 1 function in the TJ barrier and enhances the TJ barrier.

Original languageEnglish (US)
Pages (from-to)C753-C765
JournalAmerican Journal of Physiology - Cell Physiology
Volume316
Issue number5
DOIs
StatePublished - May 1 2019

Fingerprint

Tight Junctions
Occludin
Autophagy
Caco-2 Cells
Endocytosis
Autophagy-Related Proteins
Beclin-1
Permeability
Colon
Tight Junction Proteins
Peptides
Membranes
Sirolimus
Starvation
Inflammatory Bowel Diseases
Small Interfering RNA
Transfection
Cell Survival
Proteins

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cell Biology

Cite this

Wong, Morgan ; Ganapathy, Ashwinkumar Subramenium ; Suchanec, Eric ; Laidler, Laura ; Ma, Thomas ; Nighot, Prashant. / Intestinal epithelial tight junction barrier regulation by autophagy-related protein ATG6/beclin 1. In: American Journal of Physiology - Cell Physiology. 2019 ; Vol. 316, No. 5. pp. C753-C765.
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Intestinal epithelial tight junction barrier regulation by autophagy-related protein ATG6/beclin 1. / Wong, Morgan; Ganapathy, Ashwinkumar Subramenium; Suchanec, Eric; Laidler, Laura; Ma, Thomas; Nighot, Prashant.

In: American Journal of Physiology - Cell Physiology, Vol. 316, No. 5, 01.05.2019, p. C753-C765.

Research output: Contribution to journalArticle

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