sGC Activity and Regulation of Blood Flow in a Zebrafish Model System.

Soluble guanylyl cyclase (sGC) protein is a heterodimer formed by two subunits encoded by and genes. The chromosomal locus 4q32.1 harbors both of these genes, which has been previously significantly associated with coronary artery disease, myocardial infarction, and high blood pressure. Blood pressure is influenced by both the environment and genetics and is complemented by several biological pathways. The underlying mechanisms associated with this locus and its genes still need to be investigated. In the current study, we aimed to establish the zebrafish as a model organism to investigate the mechanisms surrounding sGC activity and blood pressure. A zebrafish mutant line was generated using the CRISPR-Cas9 system by inducing a 4-bp deletion frameshift mutation. This mutation resulted in a reduction of expression in both heterozygote and homozygote zebrafish. Blood flow parameters (blood flow, arterial pulse, linear velocity, and vessel diameter) investigated in the mutants showed a significant increase in blood flow and linear velocity, which was augmented in the homozygotes. No significant differences were observed for the blood flow parameters measured from larvae with individual morpholino downregulation of and , but an increase in blood flow and linear velocity was observed after co-morpholino downregulation of both genes. In addition, the pharmacological sGC stimulator BAY41-2272 rescued the impaired cGMP production in the zebrafish mutant larvae. Downregulation of gene did not show any significant difference on the blood flow parameters in both wild-type and background larvae. In summary, we successfully established a zebrafish platform for investigating sGC-associated pathways and underlying mechanisms in depth. This model system will have further applications, including for potential drug screening experiments.