The precursor osteoblast-like cell, MC3T3-E1 cell line, enhances sodium-calcium exchanger 1 (Ncx1) gene expression by stretch stimuli prior to osteoblast differentiation

This study evaluated the expression of genes involved in the concentration of Ca²⁺ in precursor osteoblast-like cell, MC3T3-E1 subjected to stretching stimuli. Transient receptor potential vanilloid 4 (Trpv4) gene expression, the factor that is activated by stretch stimulation and enables inflow of Ca²⁺ from the extracellular space, was not affected as a result of stretch stimulation; conversely, the expression of sodium-calcium exchanger 1 (Ncx1) gene involved in outflow of intracellular Ca²⁺ increased, depending on stimulation intensity. Localization of Ca²⁺ correlated with the positioning of the endoplasmic reticulum, and intracellular Ca²⁺ decreased in inverse proportion to the intensity of the stretching force. These results suggest that stretch stimulation activates intracellular Ca²⁺ elimination rather than Ca²⁺ uptake before osteoblast differentiation.

Regulation of cardiac and renal ischemia-reperfusion injury by microRNAs

Tissue damage caused by ischemia-reperfusion (I/R) injury represents a serious event, which often leads to deterioration or even loss of organ function. I/R injury is associated with transient tissue oxygen deprivation due to vessel occlusion and a subsequent reperfusion period following restoration of blood flow. Initial tissue damage inflicted by ischemia is aggravated in the reperfusion period through mechanisms such as burst of reactive oxygen and nitrogen species and inflammatory reactions. I/R injury occurs during surgical interventions, organ transplantation, diseases such as myocardial infarction, circulatory shock, and toxic insults. Recently, microRNAs have come into focus as powerful regulators of gene expression and potential diagnostic tools during I/R injury. These small noncoding ribonucleotides (~22 nucleotides in length) posttranscriptionally target mRNAs, culminating in suppression of protein synthesis or increase in mRNA degradation, thus fundamentally influencing organ function. This review highlights the latest developments regarding the role of microRNAs in cardiac and renal I/R injury.