Abstract
.Significance: Whether or not capillary pericytes contribute to blood flow regulation in the brain and retina has long been debated. This was partly caused by failure of detecting the contractile protein -smooth muscle actin (-SMA) in capillary pericytes.Aim: The aim of this review is to summarize recent developments in detecting -SMA and contractility in capillary pericytes and the relevant literature on the biology of actin filaments.Results: Evidence suggests that for visualization of the small amounts of -SMA in downstream mid-capillary pericytes, actin depolymerization must be prevented during tissue processing. Actin filaments turnover is mainly based on de/re-polymerization rather than transcription of the monomeric form, hence, small amounts of -SMA mRNA may evade detection by transcriptomic studies. Similarly, transgenic mice expressing fluorescent reporters under the -SMA promoter may yield low fluorescence due to limited transcriptional activity in mid-capillary pericytes. Recent studies show that pericytes including mid-capillary ones express several actin isoforms and myosin heavy chain type 11, the partner of -SMA in mediating contraction. Emerging evidence also suggests that actin polymerization in pericytes may have a role in regulating the tone of downstream capillaries.Conclusions: With guidance of actin biology, innovative labeling and imaging techniques can reveal the molecular machinery of contraction in pericytes.
Highlights
Since their first identification by Rouget,[1] pericytes have been hypothesized to have a role in capillary blood flow regulation
With guidance of actin biology, innovative labeling and imaging techniques can reveal the molecular machinery of contraction in pericytes
Pericytes located over the first- to fourth-order capillaries and their junctions, all of which exhibit high luminal coverage and α-smooth muscle actin (α-SMA) expression, have convinced most researchers that they might regulate the blood flow by contracting or relaxing.[6,7,8,9,10,11,14]
Summary
With guidance of actin biology, innovative labeling and imaging techniques can reveal the molecular machinery of contraction in pericytes. Paper 21042SSVR received Sep. 9, 2021; accepted for publication Dec. 22, 2021; published online Jan. 24, 2022
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call