Abnormal phenotype of in vitro dermal fibroblasts from patients with pseudoxanthoma elasticum (PXE)

Abstract

Pseudoxanthoma elasticum (PXE) is a genetic connective tissue disease, whose gene and pathogenesis are still unknown. Dermal fibroblasts from patients affected by PXE have been compared in vitro with fibroblasts taken from sex and age-matched normal individuals. Cells were grown and investigated in monolayer, into three-dimensional collagen gels and in suspension. Compared with normal cells, PXE fibroblasts cultured in monolayer entered more rapidly within the S phase and exhibited an increased proliferation index; on the contrary, similarly to normal fibroblasts, PXE cells did not grow in suspension. Furthermore, compared with normal fibroblasts, PXE cells exhibited lower efficiency in retracting collagen type I lattices and lower adhesion properties to collagen type I and to plasma fibronectin. This behavior was associated with higher expression of integrin subunits alpha2, alpha5, alphav, whereas beta1 subunit as well as alpha2beta1 and alpha5beta1 integrin expression was lower than in controls. Compared to controls, PXE fibroblasts had higher CAM protein expression in accordance with their high tendency to form cellular aggregates, when kept in suspension. The demonstration that PXE fibroblasts have altered cell-cell and cell-matrix interactions, associated with modified proliferation capabilities, is consistent with the hypothesis that the gene responsible for PXE might have a broad regulatory role on the cellular machinery.

Pseudoxanthoma Elasticum: Genetic Variations in Antioxidant Genes Are Risk Factors for Early Disease Onset

“…An alternative hypothesis is that the disease is caused by local dysfunction of the protein within the connective tissue itself, e.g., in fibroblasts. This hypothesis is supported by the fact that PXE fibroblasts show an aberrant phenotype in vitro (39 ). The presence of oxidative stress in cultured PXE cells is also consistent with a local cause.…”

Matrix Gla protein is involved in elastic fiber calcification in the dermis of pseudoxanthoma elasticum patients

“…They were also diagnosed by ultrastructural analysis of skin biopsies and by identification of ABCC6 mutations on both alleles. 28 Fibroblast cultures were established and maintained according to Quaglino et al 29 Briefly, skin biopsies were fragmented and cells were grown as monolayer in 75 cm flasks (Nunc, Roskilde, Denmark) in Dulbecco's modified Eagle's medium (DMEM) containing 10% fetal bovine serum (FBS) and used between the third and the tenth passage in vitro. Control and PXE cells were used at the same passage within each experiment.…”

“…It has been repeatedly reported that fibroblasts from patients, despite their very low or absent expression of the PXE causative gene, 39 exhibit and maintain, at least up to the tenth passage in vitro, behavioral, 29 biochemical, 40,41 and degradation 42 properties different from controls. Therefore, PXE fibroblasts seem to bear permanent metabolic alterations that are maintained when cultured in vitro and that, in vivo, could be responsible for local clinical manifestations.…”

Gene expression profiling of ABC transporters in dermal fibroblasts of pseudoxanthoma elasticum patients identifies new candidates involved in PXE pathogenesis

“…24 Moreover, dermal fibroblasts expanded from PXE patients' biopsies exhibited pathological alterations compared to dermal fibroblasts from healthy controls. 25 These cells have been shown to synthesize abnormal proteoglycans and to exhibit a higher expression of elastin (ELN), which was further associated with pathological assembly of elastic fibers when cultured in the presence of PXE sera. 16, 26 Quaglino et al 27 reported that PXE fibroblasts have a raised matrix metallopeptidase 2 mRNA and protein expression.…”