Abstract: TH-PO1078
Vasohibin 1 Is Essential for the Post-Transcriptional Modification of α-Tubulin on Microtubules in Podocytes
Session Information
- Glomerular Diseases: Podocyte Biology - I
November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1204 Podocyte Biology
Authors
- Morioka, Tomoyo, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- Tanabe, Katsuyuki, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- Tanimura, Satoshi, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- Sugiyama, Hitoshi, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- Wada, Jun, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
Background
Microtubules in podocytes are important for maintaining the characteristic cell shape as well as normal intracellular transport and dynamic morphologic alterations. The microtubule functions are affected by various post-transcriptional modifications on tubulin proteins. Recent studies have shown that vasohibin-1 (VASH1), an endothelium-derived angiogenesis inhibitor, has an enzymatic activity that catalyzes the detyrosination of α-tubulin in neurons and cancer cells. In the present study, we examined the roles of VASH1 in the modification of α-tubulin and microtubules in podocytes.
Methods
We used B6 wild-type and Vash1+/- mice to confirm the localization of detyrosinated (detyr) α-tubulin in the kidney. In addition, 8-week-old female BALB/c wild-type mice received single intravenous injection of 15mg/kg of adriamycin (ADM) or saline to induce podocyte injury and proteinuria. Finally, we cultured immortalized human podocytes, and VASH1 knockdown was performed by siRNA transfection.
Results
In wild-type mice, detyr-α-tubulin was shown to be restricted in podocytes by double immunofluorescence with podocalixyn. The detyr-α-tubulin staining was markedly attenuated in Vash1+/- mice. ADM-induced podocyte injury in BALB/c mice led to massive albuminuria and decreased detyr-α-tubulin staining in glomeruli compared to the control group, suggesting the detyrosination of α-tubulin could be altered by morphological changes of podocytes. In vitro experiments, immunoblot analysis demonstrated that detyr-α-tubulin remarkably increased in differentiated podocytes compared to undifferentiated cells. In addition, VASH1 knockdown by transfection of siRNA in differentiated podocytes significantly inhibited the detyrosination of α-tubulin.
Conclusion
These results indicate that VASH1 expression is necessary for the detyrosination of α-tubulin in podocytes, and may be involved in the regulation of their microtubule function.
Funding
- Government Support - Non-U.S.