👤 Richard Woodman

Myocardial oxygenation is impaired in hypertrophic cardiomyopathy (HCM) patients with left ventricular hypertrophy (LVH), and possibly also in HCM gene carriers without LVH. Whether these oxygenation changes are also associated with abnormalities in diastolic function or left ventricular (LV) strain are unknown. We evaluated 60 subjects: 20 MYBPC3 gene positive patients with LVH (G+LVH+), 18 MYBPC3 gene positive without LVH (G+LVH-), 11 gene negative siblings (G-), and 11 normal controls (NC). All subjects underwent 2D transthoracic echocardiography and cardiovascular magnetic resonance imaging for assessment of ventricular volumes, mass, and myocardial oxygenation at rest and adenosine stress using the blood oxygen level dependent (BOLD) technique. Maximal septal thickness was 20 mm in the G+LVH+ group, vs. 9 mm for the G+LVH- group. As expected, the G+LVH+ group had a more blunted myocardial oxygenation response to stress when compared with the G+LVH- group (-5% ± 3% vs. 2% ± 4%, P < 0.05), G- siblings (-5% ± 3% vs. 11% ± 4%, P < 0.0001) and NC (-5% ± 3% vs. 15% ± 4%, P < 0.0001). A blunted BOLD response to stress was also seen in G+LVH- subjects when compared with gene negative siblings (2% ± 4% vs. 11% ± 4%, P < 0.05) and NC (15% ± 4%, P < 0.050). G+LVH+ patients exhibited abnormal diastolic function including lower E', higher E to E' ratio and greater left atrial area compared with the G+LVH- subjects who all had normal values for these indices. Myocardial deoxygenation during stress is observed in MYBPC3 HCM patients, even in the presence of normal LV diastolic function, LV global longitudinal strain, and LV wall thickness. Show less

The dynamin-like protein, Vps1, is a GTPase involved in cargo sorting and membrane remodeling in multiple cellular trafficking pathways. Recently, Vps1 has been shown to genetically interact with ESCRT subunits. We tested the hypothesis that the functional connection of Vps1 with some of these subunits of ESCRT complexes occurs via a physical interaction. By utilizing the yeast two-hybrid system, we revealed that Vps1 physically interacts with the ESCRT-II subunits, Vps22 and Vps36, and the ESCRT-III subunit Vps24. We found that Vps1 and ESCRT-II components colocalize with Pep12, an endosomal marker. Additionally, loss of Vps1 or depletion of the GTPase activity of Vps1 results in a moderate defect in Cps1 targeting to the vacuole. Here, we discussed the potential implications of Vps1 and ESCRT interaction and their roles in the endosome-to-vacuole traffic. In summary, yeast dynamin interacts with ESCRT II and III complexes, and it functions in Cps1 trafficking toward the vacuole. Show less