Molecular alterations due to Col5a1 Haploinsufficiency in a mouse model of classic Ehlers Danlos syndrome.

Type V collagen is a regulatory fibrillar collagen essential for type I collagen fibril nucleation and organization and its deficiency leads to structurally abnormal extracellular matrix. Haploinsufficiency of the Col5a1 gene encoding α(1) chain of type V collagen is the primary cause of classic Ehlers Danlos Syndrome (EDS). The mechanisms by which this initial insult leads to the spectrum of clinical presentation is not fully understood. Using transcriptome analysis of skin and Achilles tendons from Col5a1 haploinsufficient (Col5a1+/-) mice, we recognized molecular alterations associated with the tissue phenotypes. We identified dysregulation of extracellular matrix components including thrombospondin-1, lysyl oxidase, and lumican in the skin of Col5a1+/- mice when compared to control. We also identified upregulation of Tgf-β in serum and increased expression of pSmad2 in skin from Col5a1+/- mice suggesting Tgf-β dysregulation as a contributor for abnormal wound healing and atrophic scaring seen in classic EDS. Together, these findings support altered matrix to cell signaling as a component of the pathogenesis of the tissue phenotype in classic EDS and point out potential downstream signaling pathways that may be targeted for treatment of the disease.