Nanoscale remodeling of ryanodine receptor cluster size underlies cerebral microvascular dysfunction in Duchenne muscular dystrophy

Harry A.T. Pritchard, Paulo W. Pires, Evan Yamasaki, Pratish Thakore, Scott Earley

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Duchenne muscular dystrophy (DMD) results from mutations in the gene encoding dystrophin which lead to impaired function of skeletal and cardiac muscle, but little is known about the effects of the disease on vascular smooth muscle cells (SMCs). Here we used the mdx mouse model to study the effects of mutant dystrophin on the regulation of cerebral artery and arteriole SMC contractility, focusing on an important Ca2+-signaling pathway composed of type 2 ryanodine receptors (RyR2s) on the sarcoplasmic reticulum (SR) and largeconductance Ca2+-activated K+ (BK) channels on the plasma membrane. Nanoscale superresolution image analysis revealed that RyR2 and BKα were organized into discrete clusters, and that the mean size of RyR2 clusters that colocalized with BKα was larger in SMCs from mdx mice (~62 RyR2 monomers) than in controls (~40 RyR2 monomers). We further found that the frequency and signal mass of spontaneous, transient Ca2+-release events through SR RyR2s ("Ca2+ sparks") were greater in SMCs from mdx mice. Patch-clamp electrophysiological recordings indicated a corresponding increase in Ca2+-dependent BK channel activity. Using pressure myography, we found that cerebral pial arteries and parenchymal arterioles from mdx mice failed to develop appreciable spontaneous myogenic tone. Inhibition of RyRs with tetracaine and blocking of BK channels with paxilline restored myogenic tone to control levels, demonstrating that enhanced RyR and BK channel activity is responsible for the diminished pressure-induced constriction of arteries and arterioles from mdx mice.We conclude that increased size of RyR2 protein clusters in SMCs from mdx mice increases Ca2+ spark and BK channel activity, resulting in cerebral microvascular dysfunction.

Original languageEnglish (US)
Pages (from-to)E9745-E9752
JournalProceedings of the National Academy of Sciences of the United States of America
Volume115
Issue number41
DOIs
StatePublished - Oct 9 2018
Externally publishedYes

Keywords

  • Ca signaling
  • Ion channels
  • Smooth muscle
  • Superresolution microscopy
  • Vasoconstriction

ASJC Scopus subject areas

  • General

Fingerprint

Dive into the research topics of 'Nanoscale remodeling of ryanodine receptor cluster size underlies cerebral microvascular dysfunction in Duchenne muscular dystrophy'. Together they form a unique fingerprint.

Cite this