Fibrostenotic Phenotype of Myofibroblasts in Crohn's Disease is Dependent on Tissue Stiffness and Reversed by LOX Inhibition

J Crohns Colitis. 2018 Jun 28;12(7):849-859. doi: 10.1093/ecco-jcc/jjy036.

Abstract

Background and aims: Crohn's disease is a chronic inflammatory disorder of the intestine and often leads to fibrosis, characterized by excess extracellular matrix [ECM] deposition, increased tissue stiffness, and stricture formation. Here we evaluated the contribution of myofibroblast-ECM interactions to the development of intestinal fibrosis in Crohn's disease.

Methods: Matched primary human myofibroblasts were isolated from stenotic, inflamed and normal-appearing small intestine within the same Crohn's disease patient [n = 10]. Cells were analyzed by gene expression profiling, microscopy and functional assays, including matrix metalloproteinase [MMP] production and ECM contraction.

Results: We demonstrated that myofibroblasts isolated from stenotic intestine differed both in phenotype and function from those isolated from purely inflammatory or normal-appearing intestine of the same patient. Stenotic myofibroblasts displayed increased expression of genes associated with ECM modulation and collagen deposition. Upon culture in a fibrotic environment, normal myofibroblasts increased expression of MMPs to counteract the mechanical force exerted by the matrix. Interestingly, stenotic myofibroblasts showed a paradoxical response with decreased expression of MMP3. In addition, stenotic myofibroblasts expressed increased levels of the collagen crosslinking enzyme lysyl oxidase [LOX] and induced significantly more ECM contraction than both normal and inflamed myofibroblasts. Importantly, LOX inhibition completely restored MMP3 activity in stenotic myofibroblasts grown in a fibrotic environment, and prevented excessive ECM contraction.

Conclusions: Together these data indicate aberrancies in the myofibroblast-ECM interaction in Crohn's disease, and identify LOX inhibition as a potential anti-fibrotic agent in this condition.

MeSH terms

  • Adolescent
  • Adult
  • Cells, Cultured
  • Constriction, Pathologic / etiology
  • Constriction, Pathologic / metabolism
  • Constriction, Pathologic / pathology
  • Crohn Disease / complications
  • Crohn Disease / genetics
  • Crohn Disease / pathology*
  • Elasticity
  • Extracellular Matrix / metabolism*
  • Female
  • Humans
  • Inflammation / metabolism
  • Inflammation / pathology
  • Male
  • Matrix Metalloproteinase 3 / metabolism
  • Myofibroblasts / metabolism*
  • Myofibroblasts / pathology*
  • Phenotype
  • Protein-Lysine 6-Oxidase / antagonists & inhibitors
  • Protein-Lysine 6-Oxidase / metabolism*
  • Transcriptome
  • Young Adult

Substances

  • LOX protein, human
  • Protein-Lysine 6-Oxidase
  • MMP3 protein, human
  • Matrix Metalloproteinase 3