Major non-cardiac surgery is a risk factor for rapid hemodynamic progression of non-rheumatic aortic stenosis.

BACKGROUND: Inflammatory processes are suggested to play a pathogenic role in the development and progression of non-rheumatic aortic stenosis (AS). Major surgery causes an inflammatory reaction. With the increasing prevalence of non-rheumatic AS, the number of affected patients undergoing major surgery increases. We hypothesized that major non-cardiac surgery (MNCS) could accelerate the progression of non-rheumatic AS. METHODS AND RESULTS: We enrolled 218 consecutive patients with non-rheumatic AS who underwent transthoracic echocardiography (TTE) at least twice more than 6 months apart. Study patients were divided into the MNCS group and the non-MNCS group. The MNCS group consisted of patients who underwent MNCS during the TTE follow-up interval. At baseline, peak pressure gradient across the aortic valve (AVG) was similar between the groups. Also baseline clinical characteristics and TTE follow-up interval were similar. The annual rate of peak AVG increase was much higher in the MNCS group than in the non-MNCS group. The proportion of patients with rapid hemodynamic progression was much higher in the MNCS group than in the non-MNCS group. Multiple logistic regression analysis showed that MNCS was an independent predictor of rapid hemodynamic progression of non-rheumatic AS. CONCLUSIONS: The present study indicates for the first time that MNCS is associated with the rapid progression of non-rheumatic AS.

cGMP-dependent protein kinase I is involved in neurite outgrowth via a Rho effector, rhotekin, in Neuro2A neuroblastoma cells.

Although the cGMP/cGMP-dependent protein kinase (cGK) signaling is involved in the regulation of neurite outgrowth, its mechanism remains to be clarified. In this study, we identified a Rho effector, rhotekin, as a cGK-I-interacting protein. Rhotekin was also a substrate for cGK-Iα. In neurite-extended Neuro2A neuroblastoma cells, cGK-Iα and rhotekin were colocalized in the plasma membrane and extended neurites, while treatment with cGMP resulted in translocation of rhotekin to the cytoplasm. In addition, we found that cGK-Iα and rhotekin synergistically suppressed Rho-induced neurite retraction. Our findings suggest that cGK-Iα interacts with and phosphorylates rhotekin, thereby contributing to neurite outgrowth regulation.

Trafficking of cGMP-dependent protein kinase II via interaction with Rab11.

cGMP-dependent protein kinase II (cGK-II) is implicated in several physiological functions including intestinal secretion, bone growth, and learning and memory, but the detailed mechanisms are still unclear. To identify proteins that are involved in cGMP/cGK-II signaling, we performed yeast two-hybrid screening and identified Rab11b as a cGK-II-interacting protein that regulates the slow-recycling pathway. Interestingly, cGK-II interacted with the GDP-bound form of Rab11b (Rab11b S25N), but not the GTP-bound form, in mammalian cells. Immunofluorescence staining revealed that Rab11b S25N promoted the translocation of cGK-II from the plasma membrane to the cytoplasm and that the localization of cGK-II extensively overlapped with Rab11b. Furthermore, treatment with a membrane-permeable cGMP analog caused the rapid retranslocation of cGK-II and Rab11b S25N to the membrane. These data indicate that Rab11b is necessary for the trafficking of cGK-II and that the cGMP/cGK-II signaling pathway is closely related to Rab11b recycling pathway.