BCL-2 Modulates IRE1α Activation to Attenuate Endoplasmic Reticulum Stress and Pulmonary Fibrosis

BCL-2 family members are known to be implicated in survival in numerous biological settings. Here, we provide evidence that in injury and repair processes in lungs, BCL-2 mainly acts to attenuate endoplasmic reticulum (ER) stress and limit extracellular matrix accumulation. Days after an intratracheal bleomycin challenge, mice lose a fraction of their alveolar type II epithelium from terminal ER stress driven by activation of the critical ER sensor and stress effector IRE1α. This fraction is dramatically increased by BCL-2 inhibition, because IRE1α activation is dependent on its physical association with the BCL-2-proapoptotic family member BAX, and we found BCL-2 to disrupt this association in vitro. In vivo, navitoclax (a BCL-2/BCL-xL inhibitor) given 15-21 days after bleomycin challenge evoked strong activation of IRE-1α in mesenchymal cells and markers of ER stress, but not apoptosis. Remarkably, after BCL-2 inhibition, bleomycin-exposed mice demonstrated persistent collagen accumulation at Day 42, compared with resolution in controls. Enhanced fibrosis proved to be due to the RNAase activity of IRE1α downregulating MRC2 mRNA and protein, a mediator of collagen turnover. The critical role of MRC2 was confirmed in precision-cut lung slice cultures of Day-42 lungs from bleomycin-exposed wild-type and MRC2 null mice. Soluble and tissue collagen accumulated in precision-cut lung slice cultures from navitoclax-treated, bleomycin-challenged mice compared with controls, in a manner nearly identical to that of challenged but untreated MRC2 null mice. Thus, apart from mitochondrial-based antiapoptosis, BCL-2 functions to attenuate ER stress responses, fostering tissue homeostasis and injury repair.

Errataetall:

CommentIn: Am J Respir Cell Mol Biol. 2024 Apr;70(4):231-232. - PMID 38259233

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:70

Enthalten in:

American journal of respiratory cell and molecular biology - 70(2024), 4 vom: 29. Apr., Seite 247-258

Sprache:

Englisch

Beteiligte Personen:

Le Saux, Claude Jourdan [VerfasserIn]
Ho, Tsung Che [VerfasserIn]
Brumwell, Alexis M [VerfasserIn]
Kathiriya, Jaymin J [VerfasserIn]
Wei, Ying [VerfasserIn]
Hughes, Jun-Wei B [VerfasserIn]
Garakani, Kiana [VerfasserIn]
Atabai, Kamran [VerfasserIn]
Auyeung, Vincent C [VerfasserIn]
Papa, Ferroz R [VerfasserIn]
Chapman, Harold A [VerfasserIn]

Links:

Volltext

Themen:

11056-06-7
9007-34-5
Alveolar epithelial cells
Aniline Compounds
Bcl-2
Bleomycin
Collagen
EC 2.7.11.1
EC 3.1.-
ER stress
Endoribonucleases
Fibroblast
Fibrosis
Journal Article
Navitoclax
Protein Serine-Threonine Kinases
Sulfonamides
XKJ5VVK2WD

Anmerkungen:

Date Completed 03.04.2024

Date Revised 03.04.2024

published: Print

CommentIn: Am J Respir Cell Mol Biol. 2024 Apr;70(4):231-232. - PMID 38259233

Citation Status MEDLINE

doi:

10.1165/rcmb.2023-0109OC

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM366079247