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- Title
Interaction between endoplasmic/sarcoplasmic reticulum stress (ER/SR stress), mitochondrial signaling and Ca<sup>2+</sup> regulation in airway smooth muscle (ASM)<sup>1</sup>.
- Authors
Delmotte, Philippe; Sieck, Gary C.
- Abstract
Airway inflammation is a key aspect of diseases such as asthma. Several inflammatory cytokines (e.g., TNFα and IL-13) increase cytosolic Ca2+ ([Ca2+]cyt) responses to agonist stimulation and Ca2+ sensitivity of force generation, thereby enhancing airway smooth muscle (ASM) contractility (hyper-reactive state). Inflammation also induces ASM proliferation and remodeling (synthetic state). In normal ASM, the transient elevation of [Ca2+]cyt induced by agonists leads to a transient increase in mitochondrial Ca2+ ([Ca2+]mito) that may be important in matching ATP production with ATP consumption. In human ASM (hASM) exposed to TNFα and IL-13, the transient increase in [Ca2+]mito is blunted despite enhanced [Ca2+]cyt responses. We also found that TNFα and IL-13 induce reactive oxidant species (ROS) formation and endoplasmic/sarcoplasmic reticulum (ER/SR) stress (unfolded protein response) in hASM. ER/SR stress in hASM is associated with disruption of mitochondrial coupling with the ER/SR membrane, which relates to reduced mitofusin 2 (Mfn2) expression. Thus, in hASM it appears that TNFα and IL-13 result in ROS formation leading to ER/SR stress, reduced Mfn2 expression, disruption of mitochondrion-ER/SR coupling, decreased mitochondrial Ca2+ buffering, mitochondrial fragmentation, and increased cell proliferation.
- Subjects
ENDOPLASMIC reticulum; SARCOPLASMIC reticulum; AIRWAY (Anatomy); SMOOTH muscle; ASTHMA; CYTOKINES; ADENOSINE triphosphate
- Publication
Canadian Journal of Physiology & Pharmacology, 2015, Vol 93, Issue 2, p97
- ISSN
0008-4212
- Publication type
Article
- DOI
10.1139/cjpp-2014-0361