Targeting transcriptional control of soluble guanylyl cyclase via NOTCH for prevention of cardiovascular disease

Soluble guanylyl cyclase (sGC) is an effector enzyme of nitric oxide (NO). Recent work has unravelled how levels of this enzyme are controlled, and highlighted a role in vascular disease. We provide a timely summary of available knowledge on transcriptional regulation of sGC, including influences from the NOTCH signalling pathway and genetic variants. It is speculated that hypertension-induced repression of sGC starts a vicious circle that can be initiated by periods of stress, diet or genetic factors, and a key tenet is that reduction in sGC further raises blood pressure. The idea that dysregulation of sGC contributes to syndromes caused by defective NOTCH signalling is advanced, and we discuss drug repositioning for vascular disease prevention. The advantage of targeting sGC expression rather than activity is also considered. It is argued that transcriptional inputs on sGC arise from interactions with other cells, the extracellular matrix and microRNAs (miRNAs), and concluded that the promise of sGC as a target for prevention of cardiovascular disease has increased in recent time.

Spontaneous activity and stretch-induced contractile differentiation are reduced in vascular smooth muscle of miR-143/145 knockout mice

AIM

Stretch is essential for maintaining the contractile phenotype of vascular smooth muscle cells, and small non-coding microRNAs are known to be important in this process. Using a Dicer knockout model, we have previously reported that microRNAs are essential for stretch-induced differentiation and regulation of L-type calcium channel expression. The aim of this study was to investigate the importance of the smooth muscle-enriched miR-143/145 microRNA cluster for stretch-induced differentiation of the portal vein.

METHODS

Contractile force and depolarization-induced calcium influx were determined in portal veins from wild-type and miR-143/145 knockout mice. Stretch-induced contractile differentiation was investigated by determination of mRNA expression following organ culture for 24 h under longitudinal load by a hanging weight.

RESULTS

In the absence of miR-143/145, stretch-induced mRNA expression of contractile markers in the portal vein was reduced. This was associated with decreased amplitude of spontaneous activity and depolarization-induced contractile and intracellular calcium responses, while contractile responses to 5-HT were largely maintained. We found that these effects correlated with a reduced basal expression of the pore-forming subunit of L-type calcium channels and an increased expression of CaMKIIδ and the transcriptional repressor DREAM.

CONCLUSION

Our results suggest that the microRNA-143/145 cluster plays a role in maintaining stretch-induced contractile differentiation and calcium signalling in the portal vein. This may have important implications for the use of these microRNAs as therapeutic targets in vascular disease.