TY - JOUR
T1 - Hypoxia-induced Phenotypic Switch of Fibroblasts to Myofibroblasts through a Matrix Metalloproteinase 2/Tissue Inhibitor of Metalloproteinase-mediated Pathway
T2 - Implications for Venous Neointimal Hyperplasia in Hemodialysis Access
AU - Misra, Sanjay
AU - Fu, Alex A.
AU - Misra, Khamal D.
AU - Shergill, Uday M.
AU - Leof, Edward B.
AU - Mukhopadhyay, Debabrata
PY - 2010/6
Y1 - 2010/6
N2 - Purpose: Hemodialysis grafts fail because of venous neointimal hyperplasia formation caused by adventitial fibroblasts that have become myofibroblasts (ie, α-smooth muscle actin [SMA]-positive cells) and migrate to the neointima. There is increased expression of hypoxia-inducible factor (HIF)-1α in venous neointimal hyperplasia formation in experimental animal models and clinical samples. It was hypothesized that, under hypoxic stimulus (ie, HIF-1α), fibroblasts will convert to myofibroblasts through a matrix metalloproteinase (MMP)-2-mediated pathway. Materials and Methods: Murine AKR-2B fibroblasts were made hypoxic or normoxic for 24, 48, and 72 hours. Protein expression for HIF-1α, α-SMA, MMP-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, and TIMP-2 was performed to determine the kinetic changes of these proteins. Immunostaining for α-SMA, collagen, and fibronectin was performed. Results: At all time points, there was significantly increased expression of HIF-1α in the hypoxic fibroblasts compared with normoxic fibroblasts (P < .05). There was significantly increased expression of α-SMA at all time points, which peaked by 48 hours in hypoxic fibroblasts compared with normoxic fibroblasts (P < .05). There was a significant increase in the expression of active MMP-2 by 48-72 hours and a significant increase in TIMP-1 by 48-72 hours by hypoxic fibroblasts (P < .05). By 72 hours, there was significant increase in TIMP-2 expression (P < .05). Immunohistochemical analysis demonstrated increased expression of α-SMA, collagen, and fibronectin as the duration of hypoxia increased. Conclusions: Under hypoxic conditions, fibroblasts will convert to myofibroblasts through an MMP-2-mediated pathway, which may provide insight into the mechanism of venous neointimal hyperplasia.
AB - Purpose: Hemodialysis grafts fail because of venous neointimal hyperplasia formation caused by adventitial fibroblasts that have become myofibroblasts (ie, α-smooth muscle actin [SMA]-positive cells) and migrate to the neointima. There is increased expression of hypoxia-inducible factor (HIF)-1α in venous neointimal hyperplasia formation in experimental animal models and clinical samples. It was hypothesized that, under hypoxic stimulus (ie, HIF-1α), fibroblasts will convert to myofibroblasts through a matrix metalloproteinase (MMP)-2-mediated pathway. Materials and Methods: Murine AKR-2B fibroblasts were made hypoxic or normoxic for 24, 48, and 72 hours. Protein expression for HIF-1α, α-SMA, MMP-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, and TIMP-2 was performed to determine the kinetic changes of these proteins. Immunostaining for α-SMA, collagen, and fibronectin was performed. Results: At all time points, there was significantly increased expression of HIF-1α in the hypoxic fibroblasts compared with normoxic fibroblasts (P < .05). There was significantly increased expression of α-SMA at all time points, which peaked by 48 hours in hypoxic fibroblasts compared with normoxic fibroblasts (P < .05). There was a significant increase in the expression of active MMP-2 by 48-72 hours and a significant increase in TIMP-1 by 48-72 hours by hypoxic fibroblasts (P < .05). By 72 hours, there was significant increase in TIMP-2 expression (P < .05). Immunohistochemical analysis demonstrated increased expression of α-SMA, collagen, and fibronectin as the duration of hypoxia increased. Conclusions: Under hypoxic conditions, fibroblasts will convert to myofibroblasts through an MMP-2-mediated pathway, which may provide insight into the mechanism of venous neointimal hyperplasia.
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U2 - 10.1016/j.jvir.2010.02.030
DO - 10.1016/j.jvir.2010.02.030
M3 - Article
C2 - 20434368
AN - SCOPUS:77952321489
SN - 1051-0443
VL - 21
SP - 896
EP - 902
JO - Journal of Vascular and Interventional Radiology
JF - Journal of Vascular and Interventional Radiology
IS - 6
ER -