Hypoxic Modulation of Fetal Vascular MLCK Abundance, Localization, and Function.

Hypoxic Modulation of Fetal Vascular MLCK Abundance, Localization, and Function. Am J Physiol Regul Integr Comp Physiol. 2020 Oct 28;: Authors: Sorensen DW, Carreon D, Williams JM, Pearce WJ Abstract Changes in vascular contractility are among the most important physiological effects of acute and chronic fetal hypoxia. Given the essential role of Myosin Light Chain Kinase (MLCK) in smooth muscle contractility, and its heterogeneous distribution, this study explores the hypothesis that subcellular changes in MLCK distribution contribute to hypoxic modulation of fetal carotid artery contractility. Relative to common carotid arteries from normoxic term fetal lambs (FN), carotids from fetal lambs gestated at high altitude (3802m) (FH) exhibited depressed contractility without changes in MLCK mRNA or protein abundance. Patterns of confocal colocalization of MLCK with aActin and MLC20 enabled calculation of subcellular MLCK fractions: 1) colocalized with the contractile apparatus; 2) colocalized with aActin distant from the contractile apparatus; 3) not colocalized with aActin. Chronic hypoxia did not affect MLCK abundance in the contractile fraction, despite a concurrent decrease in contractility. Organ culture for 72h under 1% O2 decreased total MLCK abundance in FN and FH carotid arteries, but decreased the contractile MLCK abundance only in FH carotid arteries. Correspondingly, culture under 1% O2 depressed contractility more in FH tha...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - Category: Physiology Authors: Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research