| Autor: |
Mori S; Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita City, Osaka, Japan., Kimura R; Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita City, Osaka, Japan., Morihara H; Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita City, Osaka, Japan.; Department of Pharmacology, Osaka Medical and Pharmaceutical University, Takatsuki City, Osaka, Japan., Tomimatsu M; Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita City, Osaka, Japan., Fuchigami S; Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita City, Osaka, Japan., Matsumoto K; Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita City, Osaka, Japan., Tanaka S; Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita City, Osaka, Japan., Okada Y; Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita City, Osaka, Japan., Maeda M; Laboratory of Clinical Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita City, Osaka, Japan.; Department of Medical Innovation, Medical Center for Translational Research, Osaka University Hospital, Suita City, Osaka, Japan., Obana M; Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita City, Osaka, Japan.; Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiative (OTRI), Osaka University, Suita City, Osaka, Japan.; Radioisotope Research Center, Institute for Radiation Sciences, Osaka University, Suita City, Osaka, Japan., Fujio Y; Laboratory of Clinical Science and Biomedicine, Graduate School of Pharmaceutical Sciences, Osaka University, Suita City, Osaka, Japan.; Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiative (OTRI), Osaka University, Suita City, Osaka, Japan. |
| Abstrakt: |
As cardiomyocyte loss causes heart failure, inhibition of cardiomyocyte death may be a therapeutic strategy against heart failure. In this study, we have identified Defender against cell death 1 (Dad1) as a candidate regulator of cardiomyocyte death, using complementary DNA microarray and siRNA knockdown screening. Dad1 is a subunit of oligosaccharyltransferase (OST) complex that is responsible for protein N-glycosylation; however, its function in cardiomyocytes remains unknown. Importantly, the knockdown of Dad1 using siRNA reduced the viability of neonatal rat cardiomyocytes (NRCMs), accompanied by cleaved caspase3 expression, independent of endoplasmic reticulum stress. Dad1 knockdown impaired cell spreading and reduced myofibrillogenesis in NRCMs, suggesting that Dad1 knockdown induced anoikis, apoptosis by disrupting cell-matrix interactions. Consistently, knockdown of Dad1 impaired N-glycosylation of integrins α5 and β1, accompanied by inactivation of focal adhesion kinase. When cell adhesion was enhanced using adhesamine, fibronectin, or collagen type IV, cardiomyocyte death induced by Dad1 knockdown was reduced. Dad1 knockdown decreased the expression of staurosporine and temperature sensitive 3A (Stt3A), a catalytic subunit of OST complex. Interestingly, Stt3A knockdown using Stt3A siRNA reduced the expression of Dad1, indicating that both Dad1 and Stt3A were required for OST stabilization. In conclusion, Dad1 plays an important role in maintaining the expression of mature N-glycosylated integrins and their downstream signaling molecules to suppress cardiomyocyte anoikis. |
