Project description:The interstitial and perivascular spaces of the heart contain stem-like cells including cardiac colony forming units - fibroblast (cCFU-F), a sub-fraction of SCA1+PDGFR-alpha +CD31- (S+P+) immature stromal cells with the qualities of mesenchymal stem cells, that we have characterized previously. Here we explore the role of platelet-derived growth factor receptor (PDGFR-alpha in cCFU-F and S+P+ cell niche regulation in homeostasis and repair. PDGFR-alpha signaling modulated quiescence, metabolic state, mitogenic propensity and colony formation, as well as the rate and stability of self-renewal. Exogenously administered PDGF-AB ligand had anti-aging effects on cCFU-F, akin to those seen in heterochronic parabiotic mice. Post-myocardial infarction (MI), PDGF-AB stimulated S+P+ cell proliferation and conversion to myofibroblasts through a metabolic priming effect, yet significantly enhanced anatomical and functional repair via multiple cellular processes. Our study provides a rationale for a novel therapeutic approach to cardiac injury involving stimulating endogenous repair mechanisms via activation of cardiac stem and stromal cells.
Project description:The interstitial and perivascular spaces of the heart contain stem-like cells including cardiac colony forming units - fibroblast (cCFU-F), a sub-fraction of SCA1+PDGFR-alpha +CD31- (S+P+) immature stromal cells with the qualities of mesenchymal stem cells, that we have characterized previously. Here we explore the role of platelet-derived growth factor receptor (PDGFR-alpha in cCFU-F and S+P+ cell niche regulation in homeostasis and repair. PDGFR-alpha signaling modulated quiescence, metabolic state, mitogenic propensity and colony formation, as well as the rate and stability of self-renewal. Exogenously administered PDGF-AB ligand had anti-aging effects on cCFU-F, akin to those seen in heterochronic parabiotic mice. Post-myocardial infarction (MI), PDGF-AB stimulated S+P+ cell proliferation and conversion to myofibroblasts through a metabolic priming effect, yet significantly enhanced anatomical and functional repair via multiple cellular processes. Our study provides a rationale for a novel therapeutic approach to cardiac injury involving stimulating endogenous repair mechanisms via activation of cardiac stem and stromal cells.
Project description:Cutaneous melanoma is the most aggressive skin cancer showing high mortality at advanced clinical stages. Platelet-Derived Growth Factor Receptor alpha (PDGFR-alpha) is known to strongly inhibit melanoma and endothelial cell proliferation, in vitro as well in vivo. PDGFR-alpha expression has been found to be reduced in metastatic human melanoma-biopsies, as compared to benign nevi-biopsies, thus implying a negative selection of PDGFR-alpha expressing cells, in melanoma. In the present study PDGFR-alpha was transiently overexpressed in endothelial (HUVEC) and melanoma (SK-Mel-28) human cells; a strong anti-proliferation effect was observed, along with profound effects on mRNA and miR- expression. More in detail, gene-expression profiling showed that PDGFR-alpha over-expression affects the expression of 82 genes in HUVEC (41 up-, 41 down-regulated), and 52 genes in SK-Mel-28 (43 up-, 9 down-regulated). miRNA profiling showed that 14 miRs are up-regulated and 40 are down-regulated in PDGFR-alpha overexpressing cells. Accurate validation with alternative techniques demonstrated that CXCL10 gene expression is one of the most significantly up-regulated at both gene- and protein level, in combination with a strong down-regulation of miR-503 in both HUVEC and SK-Mel-28 overexpressing PDGFR-alpha. We then demonstrate that CXCL10 is a validated miR-503 target, and that the anti-proliferation effect of PDGFR-alpha is reverted by specific CXCL-10 neutralization. Several molecular pathways were identified in cells overexpressing PDGFR-alpha, according to KEGG and Gene Ontology analysis (p < 0.01). In conclusion, PDGFR-alpha overexpression strongly inhibits endothelial- and melanoma- proliferation in a CXCL-10 dependent way, by significantly down-regulating miR-503 expression. This dataset contains the results of the microRNA analysis.
Project description:Cutaneous melanoma is the most aggressive skin cancer showing high mortality at advanced clinical stages. Platelet-Derived Growth Factor Receptor alpha (PDGFR-alpha) is known to strongly inhibit melanoma and endothelial cells proliferation, in vitro as well in vivo. PDGFR-alpha expression has been found to be reduced in metastatic human melanoma-biopsies, as compared to benign nevi-biopsies, thus implying a negative selection of PDGFR-alpha expressing cells, in melanoma. In the present study PDGFR-alpha was transiently overexpressed in endothelial (HUVEC) and melanoma (SK-Mel-28) human cells; a strong anti-proliferation effect was observed, along with profound effects on mRNA and miRNA expression. In detail, gene-expression profiling showed that PDGFR-alpha over-expression affects the expression of 82 transcripts in HUVEC (41 up-, 41 down-regulated), and 52 Transcripts in SK-Mel-28 (43 up-, 9 down-regulated). Finally, a miRNA profiling showed that 14 miRs are up-regulated and 39 are down-regulated in PDGFR-alpha overexpressing cells. Accurate validation with alternative techniques demonstrated that CXCL10 is one of the most significantly up-regulated at both gene- and protein level, in combination with a strong down-regulation of miR-503 in both HUVEC and SK-Mel-28 overexpressing PDGFR-alpha. We then demonstrate that CXCL10 is a validated miR-503 target, and that the anti-proliferation effect of PDGFR-alpha is reverted by specific CXCL-10 neutralization. In conclusion, PDGFR-alpha overexpression strongly inhibits endothelial- and melanoma- proliferation in a CXCL-10 dependent way, by significantly down-regulating miR-503 expression. This data set contains the results of the mRNA analysis.
Project description:Aberrant activation of oncogenic kinases is frequently observed in human cancers, but the underlying mechanism and resulting effects on global signaling are incompletely understood. Here, we demonstrate that the oncogenic FIP1L1-PDGFRa kinase exhibits a significantly different signaling pattern compared to PDGFRa wildtype: Interestingly, the conventional strong activation of PI3-kinase- and MAP-kinase- pathways is remarkably shifted towards a prominent activation of STAT factors. This diverging signaling pattern compared to classical PDGF-receptor signaling is partially coupled to the aberrant intracellular location of the oncogene, since membrane targeting of F/PDGFRa restores activation of MAPK- and PI3K-pathway completely. In contrast to the M-^SclassicalM-^T cytokine-induced STAT-activation process does STAT activation by F/PDGFR not require Janus kinase activity and does not involve a SH2-domain-mediated binding mechanism. Thus it is conceivable that STAT activation by F/PDGFR could be directly mediated by interaction of STAT factors with the kinase domain itself.
Project description:Kidney fibrosis is characterized by expansion and activation of platelet-derived growth factor receptor-β (PDGFR-β) positive mesenchymal cells. To study the consequences of PDGFR-ß activation, we developed a model of primary renal fibrosis using transgenic mice with PDGFR-β activation specifically in renal mesenchymal cells, driving their pathological proliferation and phenotypic switch towards myofibroblasts. This resulted in progressive mesangioproliferative glomerulonephritis, mesangial sclerosis and interstitial fibrosis with progressive anemia due to loss of erythropoietin production by fibroblasts. We used microarrays to compare wildtype animals (Foxd1_wt Pdgfrb_wt) to animals with constitutive mesenchymal PDGFR-β activation (Foxd1_mt Pdgfrb V536A) in the kidney to identify target genes of PDGFR-β signaling.
Project description:The scaffold protein synectin plays a critical role in the trafficking and regulation of membrane receptor pathways. As the platelet derived growth factor receptor (PDGFR) pathway is essential for hepatic stellate cell (HSC) activation and liver fibrosis, we sought to determine the role of synectin on the PDGFR pathway in HSC. To study the role of synectin in the development of liver fibrosis, mice with selective deletion of synectin from HSC were generated and found to be protected from fibrosis. RNAseq revealed that knockdown of synectin in HSC demonstrated reductions in the fibrosis pathway of genes including PDGFR-β, but not PDGFR-α. Chromatin Immunoprecipitation assay of the PDGFR-β promoter upon synectin knockdown revealed a pattern of histone marks associated with decreased transcription, dependent on p300. In contradistinction, synectin was found to regulate PDGFR-α through an alternative mechanism: protection from autophagic degradation. Site directed mutagenesis revealed that ubiquitination of specific PDGFR-α lysine residues is responsible for its autophagic degradation. Furthermore, functional studies showed decreased PDGF dependent proliferation and migration after synectin knockdown. Finally, human cirrhotic livers demonstrated increased synectin expression. This work provides insight into differential transcriptional and post-translational mechanisms of synectin regulation of PDGFRs, which are critical to fibrogenesis.