title: Matrix metalloproteinase 9-dependent Notch signaling contributes to kidney fibrosis through peritubular endothelial-mesenchymal transition.
abstract: BACKGROUND
  Endothelial cells are known to contribute to kidney fibrosis via endothelial-mesenchymal transition (EndoMT). Matrix metalloproteinase 9 (MMP-9) is known to be profibrotic. However, whether MMP-9 contributes to kidney fibrosis via EndoMT is unknown.
  
  
  METHODS
  Primary mouse renal peritubular endothelial cells (MRPECs) were isolated and treated by recombinant human transforming growth factor beta 1 (rhTGF-β1) with or without MMP-9 inhibitor or by recombinant human MMP-9 (rhMMP-9) alone. Kidney fibrosis was induced by unilateral ureteral obstruction (UUO) in MMP-9 knockout (KO) and wide-type (WT) control mice. The effects of MMP-9 on EndoMT of MRPECs and kidney fibrosis were examined.
  
  
  RESULTS
  We showed that MRPECs underwent EndoMT after rhTGF-β1 treatment or in UUO kidney as evidenced by decreased expression of endothelial markers, vascular endothelial cadherin (VE-cadherin) and CD31, and increased levels of mesenchymal markers, α-smooth muscle actin (α-SMA) and vimentin. The expression of fibrosis markers was also up-regulated significantly after rhTGF-β1 treatment in MRPECs. The EndoMT and fibrosis markers were significantly less in rhTGF-β1-treated MMP-9 KO MRPECs, whereas MMP-9 alone was sufficient to induce EndoMT in MRPECs. UUO kidney of MMP-9 KO mice showed significantly less interstitial fibrosis and EndoMT in MRPECs. Notch signaling shown by Notch intracellular domain (NICD) was increased, while Notch-1 was decreased in rhTGF-β1-treated MRPECs of MMP-9 WT but not MMP-9 KO mice. Inhibition of MMP-9 or Notch signaling prevented rhTGF-β1- or rhMMP-9-induced α-SMA and NICD upregulation in MRPECs. UUO kidney of MMP-9 KO mice had less staining of Notch signaling transcription factor Hey-1 in VE-cadherin-positive MRPECs than WT controls.
  
  
  CONCLUSIONS
  Our results demonstrate that MMP-9-dependent Notch signaling plays an important role in kidney fibrosis through EndoMT of MRPECs.
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.|The School of Biomedical Sciences, Chengdu Medical College, Chengdu, People's Republic of China.
authors: Ye
authors: Y
authors: Zhao
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.|Department of Nephrology, Second Hospital of Shanxi Medical University, Shanxi Kidney Disease Institute, Taiyuan, Shanxi, People's Republic of China.
authors: Xi
authors: X
authors: Qiao
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.
authors: Thian Kui
authors: TK
authors: Tan
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.|Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China.
authors: Hong
authors: H
authors: Zhao
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.|Experimental Centre of Science and Research, First Hospital of Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China.
authors: Yun
authors: Y
authors: Zhang
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.|Experimental Centre of Science and Research, First Hospital of Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China.
authors: Lixin
authors: L
authors: Liu
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.|Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China.
authors: Jianlin
authors: J
authors: Zhang
authors: Department of Nephrology, Second Hospital of Shanxi Medical University, Shanxi Kidney Disease Institute, Taiyuan, Shanxi, People's Republic of China.
authors: Lihua
authors: L
authors: Wang
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.
authors: Qi
authors: Q
authors: Cao
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.
authors: Yiping
authors: Y
authors: Wang
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.
authors: Ya
authors: Y
authors: Wang
authors: Centre for Kidney Research, Children's Hospital at Westmead, Sydney, NSW, Australia.
authors: Yuan Min
authors: YM
authors: Wang
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.
authors: Vincent W S
authors: VWS
authors: Lee
authors: Centre for Kidney Research, Children's Hospital at Westmead, Sydney, NSW, Australia.
authors: Stephen I
authors: SI
authors: Alexander
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.
authors: David C H
authors: DCH
authors: Harris
authors: Centre for Transplant and Renal Research, The Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia.
authors: Guoping
authors: G
authors: Zheng
mesh_terms: D000818:Animals; D004727:Endothelium / Q000378:metabolism / Q000473:pathology*; D005355:Fibrosis / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007674:Kidney Diseases / Q000378:metabolism / Q000473:pathology*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008648:Mesoderm / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D051880:Receptors, Notch / Q000378:metabolism*; D015398:Signal Transduction; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D014517:Ureteral Obstruction / Q000378:metabolism / Q000473:pathology
chemical_list: D051880:Receptors, Notch; D053773:Transforming Growth Factor beta1; D020780:Matrix Metalloproteinase 9
keywords: Matrix metalloproteinase 9; Notch; endothelial–mesenchymal transition; kidney fibrosis; peritubular endothelial cells