| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1From the Departments of Ophthalmology and 2Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
PURPOSE. To investigate the involvement of the Rho-kinase pathway in collagen gel contraction by hyalocytes.
METHODS. An in vitro type I collagen gel contraction assay using cultured bovine hyalocytes was performed to evaluate the effect of PDGF-BB and TGF-ß2. The effect of both cytokines on the phosphorylation of myosin light chain (MLC) was analyzed by Western blot analysis. To confirm the involvement of the Rho-kinase pathway in the collagen gel contraction, the effects of Y27632, a specific Rho-kinase inhibitor were examined. The effect of hydroxyfasudil, another potent Rho-kinase inhibitor, was also evaluated. The expression of 
-smooth muscle actin (SMA) was analyzed by Western blot analysis to examine the myofibroblast-like transdifferentiation of the hyalocytes.
RESULTS. Maximum collagen gel contraction was observed within 24 hours after treatment with PDGF-BB and much stronger contraction with TGF-ß2, whose effect was time dependent, at least up to 5 days. Although transient and maximum MLC phosphorylation by PDGF-BB was observed at 
4 hours after stimulation (180.8%, P < 0.01), TGF-ß2–elicited MLC phosphorylation occurred in a time-dependent manner at least up to 24 hours (220.0%, P < 0.01) and was maintained up to 5 days. Y27632 demonstrated significant inhibition of collagen gel contraction induced by both cytokines. Hydroxyfasudil dose-dependently (0.03–20.00 µM) prohibited the phosphorylation of MLC, and inhibited collagen gel contraction at a concentration corresponding to that which inhibited MLC phosphorylation. TGF-ß2, but not PDGF-BB, also caused myofibroblast-like transdifferentiation with SMA overexpression, which was downregulated by hydroxyfasudil in part (P < 0.01).
CONCLUSIONS. The hyalocytes have a contractile property in the presence of PDGF-BB and TGF-ß2. Whereas PDGF-BB initiates collagen gel contraction by transient activation of the Rho-kinase pathway, sustained activation of the Rho-kinase pathway and myofibroblast-like transdifferentiation appears to be involved in the TGF-ß2–dependent contractile properties of hyalocytes.
This article has been cited by other articles:
|
|
 |
|
  T. Kita, Y. Hata, R. Arita, S. Kawahara, M. Miura, S. Nakao, Y. Mochizuki, H. Enaida, Y. Goto, H. Shimokawa, et al. Role of TGF-{beta} in proliferative vitreoretinal diseases and ROCK as a therapeutic target PNAS, November 11, 2008; 105(45): 17504 - 17509. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y Hata, Y Sassa, T Kita, M Miura, K Kano, S Kawahara, R Arita, S Nakao, J L Shih, and T Ishibashi Vascular endothelial growth factor expression by hyalocytes and its regulation by glucocorticoid Br. J. Ophthalmol., November 1, 2008; 92(11): 1540 - 1544. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Kawahara, Y. Hata, T. Kita, R. Arita, M. Miura, S. Nakao, Y. Mochizuki, H. Enaida, T. Kagimoto, Y. Goto, et al. Potent Inhibition of Cicatricial Contraction in Proliferative Vitreoretinal Diseases by Statins Diabetes, October 1, 2008; 57(10): 2784 - 2793. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Kita, Y. Hata, M. Miura, S. Kawahara, S. Nakao, and T. Ishibashi Functional Characteristics of Connective Tissue Growth Factor on Vitreoretinal Cells Diabetes, May 1, 2007; 56(5): 1421 - 1428. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Kita, Y. Hata, K. Kano, M. Miura, S. Nakao, Y. Noda, H. Shimokawa, and T. Ishibashi Transforming Growth Factor-{beta}2 and Connective Tissue Growth Factor in Proliferative Vitreoretinal Diseases: Possible Involvement of Hyalocytes and Therapeutic Potential of Rho Kinase Inhibitor Diabetes, January 1, 2007; 56(1): 231 - 238. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Meyer-ter-Vehn, S. Sieprath, B. Katzenberger, S. Gebhardt, F. Grehn, and G. Schlunck Contractility as a Prerequisite for TGF-{beta}-Induced Myofibroblast Transdifferentiation in Human Tenon Fibroblasts Invest. Ophthalmol. Vis. Sci., November 1, 2006; 47(11): 4895 - 4904. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Hisatomi, H. Enaida, T. Sakamoto, T. Kanemaru, T. Kagimoto, I. Yamanaka, A. Ueno, T. Nakamura, Y. Hata, and T. Ishibashi Cellular Migration Associated With Macular Hole: A New Method for Comprehensive Bird's-Eye Analysis of the Internal Limiting Membrane Arch Ophthalmol, July 1, 2006; 124(7): 1005 - 1011. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Shimokawa and A. Takeshita Rho-Kinase Is an Important Therapeutic Target in Cardiovascular Medicine Arterioscler. Thromb. Vasc. Biol., September 1, 2005; 25(9): 1767 - 1775. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
