Presentation is loading. Please wait.

Presentation is loading. Please wait.

Mechanosensitive properties in endothelium and their roles in regulation of endothelial function Zhi-Ren Zhang M.D., Ph.D. Harbin Medical University.

Similar presentations


Presentation on theme: "Mechanosensitive properties in endothelium and their roles in regulation of endothelial function Zhi-Ren Zhang M.D., Ph.D. Harbin Medical University."— Presentation transcript:

1 Mechanosensitive properties in endothelium and their roles in regulation of endothelial function Zhi-Ren Zhang M.D., Ph.D. Harbin Medical University

2 Sensors for shear stress on vascular endothelial cells Kimiko Yamamoto. Circulation Journal. 2009

3 Endothelial cells isolated from mouse express CD31 and have primary cilia. Nauli, et al. Circulation 2008 Do vascular endothelial cells isolated from mouse express primary cilia?

4 Colocalization of polycystin-1 (PC1) and polaris. Nauli, et al. Circulation 2008 Polycystin-1 is localized in aortic endothelial cilia of embryonic mouse aorta. Does polycystin-1 (TRPP1, PKD1) express and localize in endothelial cilia of embryonic mouse aorta?

5 Fluid shear–induced calcium and transient NO require polaris and polycystin-1. Nauli, et al. Circulation 2008 Does TRPP1 or cilium play a role in regulation of endothelial function?

6 Is TRPP2 localized in the cilia of vascular endothelial cells? Human MouseWissam A. et al. Cellular biology.2009

7 Normal expression level and localization of TRPP2 in cilia is required for the endothelial cilia to sense fluid shear stress. Wissam A. et al. Cellular biology.2009

8 Fluid flow (shear stress) Cilia Polycystin-1 Polycystin-2 Ca 2+ PKC eNOS CaM Akt/PKB Ca 2+ /CaM Nitric oxide Vasodilator Mechanosensory cilia as microcompartments. Surya M, et al. International Journal of Vascular Medicine 2011

9 Are there other sensors for shear stress on vascular endothelial cells beyond what have found so far?

10 Control 5 mM Chloral hydrate (3 days) Nuclei α-tubulin Merged XZ view Do human umbilical vein endothelial cells (HUVECs) have primary cilia?

11 Are cilia involved in [Ca 2+ ] i increase in response to alteration of shear stress in HUVECs? 30s 0 10 dyne/cm 2

12 Is cilium involved in [NO] i increase in response to alteration of shear stress? 0 10 dyne/cm 2 ~75s

13 The data presented thus far indicate that there is another “secondary” sensor beyond primary cilium. What is it? We have previously indentified a functional channel complex formed by TRPP2 and TRPV4 in CCD isolated from mouse and this channel complex exerts dual functions (submitted to Cell).

14 TRPV4MergeNucleiTRPP2 WB: IP:Lysate TRPV4 IgGTRPP2 WB:TRPP2 IP:LysateIgGTRPV4 A B Do TRPP2 and TRPV4 physically interact in HUVECs? IgG

15 C Does TRPP2 or TRPV4 express in cilia of HUVECs?

16 TRPP2 TRPV4 Merged cilium Are TRPP2 and TRPV4 co-localized on cilium?

17 Are TRPP2 and TRPV4 co-localized on human mesenteric vascular endothelial cells?

18 The data presented thus far strongly suggest that TRPP2/TRPV4 physically interact in HUVECs, and that this complex expresses both in cilia and plasma membrane of HUVECs Question Does this complex play a role in response to macheno-stimuli in HUVECs?

19 qtRT-PCR demonstrating gene silencing efficiency

20 TRPP2 β-actin TRPV4 β-actin CtrlScr P2-shRNA CtrlScr P2/V4-shRNA CtrlScr V4-shRNA CtrlScr P2/V4-shRNA

21 Does knock down TRPP2 and/or TRPV4 affect [Ca 2+ ] i transient in response to alteration of shear stress in HUVECs ? 0 10 dyne/cm 2 30s

22 Does knock down TRPP2 or TRPV4 affect increase in [NO] i in response to alteration of shear stress in HUVECs ? 0 10 dyne/cm 2

23 p-AMPK AMPK p-eNOS e-NOS CtrlScr Ctrl Flow 10 min

24 p-AMPKα AMPKα CtrlScrCtrlScrCtrlScr p-eNOS e-NOS V4- shRNA P2- shRNA P2/V4- shRNA Flow 10 min p-eNOS e-NOS PI3K inhibitor (+) (-) (+) (-) (+) (-) CtrlScrCtrlScrCtrlScr P2- shRNA V4- shRNA P2/V4- shRNA

25

26 A Do TRPP2 and TRPV4 form a functional channel complex in HUVECs? baseline 100 mV TRPP2/TRPV4 forms a non-selective calcium permeable cation channel

27 There are several different machenosensors in vascular endothelial cells, including primary cilium. TRPP2 and TRPV4 assemble to form a functional channel complex in HUVECs. TRPP2/TRPV4 channel complex exerts dual functions, i. e. acting as a mechanosensor and regulating [Ca 2+ ] i and NO production in response to alternation of shear stress in HUVECs, via AMPK-p- eNOS (?).

28 Jia-Ning Zhang, Ph.D. candidate Dan Zhao, Ph.D. Associate Prof. Ying Zhao, Bing-Kun Zhang John Y.-J. Shyy, Ph.D., Prof. Univ. of California, Riverside Funding: CNSF, NIH


Download ppt "Mechanosensitive properties in endothelium and their roles in regulation of endothelial function Zhi-Ren Zhang M.D., Ph.D. Harbin Medical University."

Similar presentations


Ads by Google