Modulation of microvascular smooth muscle adhesion and mechanotransduction by integrin-linked kinase.
OBJECTIVE
In this study, we investigated the involvement of integrin-linked kinase (ILK) in the adhesion of arteriolar vascular smooth muscle cells (VSMC) to fibronectin (FN) and in the mechano-responsiveness of VSMC focal adhesions (FA).


METHODS
ILK was visualized in VSMC by expressing EGFP-ILK and it was knocked down using ILK-shRNA constructs. Atomic force microscopy (AFM) was used to characterize VSMC interactions with FN, VSMC stiffness and to apply and measure forces at a VSMC single FA site.


RESULTS
ILK was localized to FA and silencing ILK promoted cell spreading, enhanced cell adhesion, reduced cell proliferation and reduced downstream phosphorylation of GSK-3beta and PKB/Akt. AFM studies demonstrated that silencing ILK enhanced alpha5beta1 integrin adhesion to FN and enhanced VSMC contraction in response to a pulling force applied at the level of a single FN-FA site.


CONCLUSIONS
ILK functions in arteriolar VSMC appear linked to multiple signaling pathways and processes that inhibit cell spreading, cell adhesion, FA formation, adhesion to FN and the mechano-responsiveness of FN-FA sites.
Huang
Shaoxing
S
Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO 65211, USA.
Sun
Zhe
Z
Li
Zhaohui
Z
Martinez-Lemus
Luis A
LA
Meininger
Gerald A
GA
D000818:Animals; D001160:Arterioles / Q000166:cytology* / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology*; D002465:Cell Movement; D049109:Cell Proliferation; D002478:Cells, Cultured; D005353:Fibronectins / Q000378:metabolism; D022001:Focal Adhesions / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D039081:Integrin alpha5beta1 / Q000378:metabolism; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D000099200:Scaffold Protein ILK
D005353:Fibronectins; D049452:Green Fluorescent Proteins; D039081:Integrin alpha5beta1; D017346:Protein Serine-Threonine Kinases; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D000099200:Scaffold Protein ILK; C485184:enhanced green fluorescent protein