Differential effect of Cyclosporin A and FK506 on SPARC mRNA expression by human gingival fibroblasts

Gingival proteomics reveals the role of TGF beta and YAP/TAZ signaling in Raine syndrome fibrosis

Raine syndrome (RNS) is a rare autosomal recessive osteosclerotic dysplasia. RNS is caused by loss-of-function disease-causative variants of the FAM20C gene that encodes a kinase that phosphorylates most of the secreted proteins found in the body fluids and extracellular matrix. The most common RNS clinical features are generalized osteosclerosis, facial dysmorphism, intracerebral calcifications and respiratory defects. In non-lethal RNS forms, oral traits include a well-studied hypoplastic amelogenesis imperfecta (AI) and a much less characterized gingival phenotype. We used immunomorphological, biochemical, and siRNA approaches to analyze gingival tissues and primary cultures of gingival fibroblasts of two unrelated, previously reported RNS patients. We showed that fibrosis, pathological gingival calcifications and increased expression of various profibrotic and pro-osteogenic proteins such as POSTN, SPARC and VIM were common findings. Proteomic analysis of differentially expressed proteins demonstrated that proteins involved in extracellular matrix (ECM) regulation and related to the TGFβ/SMAD signaling pathway were increased. Functional analyses confirmed the upregulation of TGFβ/SMAD signaling and subsequently uncovered the involvement of two closely related transcription cofactors important in fibrogenesis, Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ). Knocking down of FAM20C confirmed the TGFβ-YAP/TAZ interplay indicating that a profibrotic loop enabled gingival fibrosis in RNS patients. In summary, our in vivo and in vitro data provide a detailed description of the RNS gingival phenotype. They show that gingival fibrosis and calcifications are associated with, and most likely caused by excessed ECM production and disorganization. They furthermore uncover the contribution of increased TGFβ-YAP/TAZ signaling in the pathogenesis of the gingival fibrosis.

New insights in collagen turnover in orofacial cleft patients

OBJECTIVE

We aimed to characterize the fibroblast phenotype of patients by analyzing gene and protein expression of cleft lip and/or cleft palate fibroblasts in relation to collagen turnover and extracellular matrix remodeling.

PATIENTS

Human palatal fibroblasts were obtained from three healthy subjects without cleft lip and/or cleft palate and from three subjects with nonsyndromic cleft lip and/or cleft palate. Collagen turnover-related gene and protein expression were analyzed by real-time polymerase chain reaction, Western and dot blots, and sodium dodecyl sulfate zymography.

RESULTS

Cleft lip and/or cleft palate fibroblasts, compared with controls, displayed a down-regulation of collagens type I and III messenger RNA (p < .0001 and p < .001, respectively) but an opposite tendency to increase protein levels. Cleft lip and/or cleft palate cells had higher lysyl hydroxylase-2b messenger RNA levels expressed in relation to collagen type I messenger RNA, down-regulated matrix metalloproteinase-1, tissue inhibitor of matrix metalloproteinase-1, and Secreted Protein Acidic and Rich in Cysteine messenger RNA (p < .0001 and p < .01, respectively). Pro-matrix metalloproteinase-1 tended to decrease, and pro-matrix metalloproteinase-2 and -9 were down-regulated (p < .01, p < .05, respectively), as was Secreted Protein Acidic and Rich in Cysteine protein expression (p < .05).

CONCLUSIONS

Our results suggest that the cleft lip and/or cleft palate fibroblast phenotype is characterized by a tendency toward interstitial collagen deposition due to posttranslational modifications, such as decreased collagen degradation by matrix metalloproteinases and increased collagen cross-links. These findings may contribute to the knowledge of the cleft lip and/or cleft palate fibroblast phenotype and may be useful to the surgeon when considering the potential wound contraction and subsequent undesired scarring in cleft lip and/or cleft palate ocurring after the surgical closure of a cleft palate.

Gene expression, cytoskeletal changes and extracellular matrix synthesis in human osteoblasts treated with cyclosporin A

Cyclosporin A (CyA) is an immunosuppressive agent used to prevent allograft rejection, but unfortunately it causes adverse effects such as bone diseases, osteoporosis and osteomalacia. These pathologies involve an imbalance between synthesis, degradation and mineralization of extracellular matrix. CyA can modify extracellular matrix components such as glycosaminoglycans (GAG) and collagen fibers. In addition, normal cell activity is dependent on cell morphology and substrate cell attachment. We treated normal human osteoblasts with CyA and analyzed: (i) gene expression by a microarray method; (ii) extracellular GAG and collagen after (3)H-glucosamine and Western blot analysis; and (iii) cytoskeletal changes, using actin and tubulin fluorescent antibodies. CyA increased intra- and extracellular GAG and extracellular GAG classes such as hyaluronic acid, chondroitin sulphate, and dermatan sulphate; there was no noteworthy effect on heparan sulphate and the ratio of non-sulphated to sulphated GAG. In osteoblast cultures the drug reduced cytoskeletal actin, while tubulin did not change. In vivo the osteoblasts showed morphological changes with different extracellular matrix synthesis. Microarray analysis indicated the inhibition of gene pathways related to Wnt signaling molecules, and the cytoskeletal and focal adhesion cascade. In in vitro human osteoblasts CyA modified gene expression related to cytoskeletal pattern organization and cell morphology. Since in bone pathologies osteoblasts show different morphology related to cell size, these data suggest that in vivo osteoblast different functions could be dependent on alteration of osteoblast differentiation.

Downregulated gene expression in human palate fibroblasts after cyclosporin A treatment

BACKGROUND

Cyclosporin A is a powerful immunosuppressive drug with considerable impact on transplants and is able to modify extracellular matrix (ECM) composition. It has recently been demonstrated that cyclosporin A stimulates the production of the cytokine family. Cytokines such as interleukin, transforming growth factor beta(1), and bone morphogenetic protein induce the deposition of glycosaminoglycans (GAGs), proteoglycans, and collagen fibers in the connective ECM. ECM composition is very important for normal tissue development and function. In this work, we examine the effects caused by cyclosporin A on cultures of normal human palate fibroblasts in order to evaluate interleukin, transforming growth factor beta II, and bone morphogenetic protein II membrane receptor induction and extracellular GAG changes such as hyaluronic acid, heparin sulfate, and chondroitin sulfate.

METHODS

Palate fibroblasts were maintained for 24 h in serum-free 199 medium containing 5 microg/mL (3)H glucosamine hydrochloride. After this time, TGF II and BMP II receptors were determined by microarray analysis and GAG classes by the biochemical method.

RESULTS

The results show that TGFbeta(1) II and BMP II membrane receptors are significantly inhibited in cyclosporin A-treated cultures as compared to controls, whereas IL-1R2 membrane receptors are stimulated. The behavior of total intra- and extracellular GAGs is significantly increased in cyclosporin A-treated cultures, whereas the ratio between non-sulfated/sulfated GAGs decreases (p <or=0.01) vis-à-vis controls.

CONCLUSIONS

Because they form a highly complicated macromolecular network in the ECM, which provides an indication of cell function and gene expression and modulates growth factor activities, GAG changes are related to modification of ECM functions. Our data show that cyclosporin A causes biochemical changes to ECM through alterations in cytokines and respective membrane receptor linkages.