scholarly journals Platelet-derived growth factor receptor-α is essential for cardiac fibroblast survival

2019 ◽  
Vol 317 (2) ◽  
pp. H330-H344 ◽  
Author(s):  
Malina J. Ivey ◽  
Jill T. Kuwabara ◽  
Kara L. Riggsbee ◽  
Michelle D. Tallquist

Platelet-derived growth factor receptor α (PDGFRα), a receptor tyrosine kinase required for cardiac fibroblast development, is uniquely expressed by fibroblasts in the adult heart. Despite the consensus that PDGFRα is expressed in adult cardiac fibroblasts, we know little about its function when these cells are at rest. Here, we demonstrate that loss of PDGFRα in cardiac fibroblasts resulted in a rapid reduction of resident fibroblasts. Furthermore, we observe that phosphatidylinositol 3-kinase signaling was required for PDGFRα-dependent fibroblast maintenance. Interestingly, this reduced number of fibroblasts was maintained long-term, suggesting that there is no homeostatic mechanism to monitor fibroblast numbers and restore hearts to wild-type levels. Although we did not observe any systolic functional changes in hearts with depleted fibroblasts, the basement membrane and microvasculature of these hearts were perturbed. Through in vitro analyses, we showed that PDGFRα signaling inhibition resulted in an increase in fibroblast cell death, and PDGFRα stimulation led to increased levels of the cell survival factor activating transcription factor 3. Our data reveal a unique role for PDGFRα signaling in fibroblast maintenance and illustrate that a 50% loss in cardiac fibroblasts does not result in lethality. NEW & NOTEWORTHY Platelet-derived growth factor receptor α (PDGFRα) is required in developing cardiac fibroblasts, but a functional role in adult, quiescent fibroblasts has not been identified. Here, we demonstrate that PDGFRα signaling is essential for cardiac fibroblast maintenance and that there are no homeostatic mechanisms to regulate fibroblast numbers in the heart. PDGFR signaling is generally considered mitogenic in fibroblasts, but these data suggest that this receptor may direct different cellular processes depending on the cell’s maturation and activation status.

Neoplasia ◽  
2009 ◽  
Vol 11 (8) ◽  
pp. 732-W7 ◽  
Author(s):  
Debora Faraone ◽  
Maria Simona Aguzzi ◽  
Gabriele Toietta ◽  
Angelo M. Facchiano ◽  
Francesco Facchiano ◽  
...  

2020 ◽  
Vol 22 (8) ◽  
pp. 1150-1161 ◽  
Author(s):  
Alexandra K Bohm ◽  
Jessica DePetro ◽  
Carmen E Binding ◽  
Amanda Gerber ◽  
Nicholas Chahley ◽  
...  

Abstract Background Imagining ways to prevent or treat glioblastoma (GBM) has been hindered by a lack of understanding of its pathogenesis. Although overexpression of platelet derived growth factor with two A-chains (PDGF-AA) may be an early event, critical details of the core biology of GBM are lacking. For example, existing PDGF-driven models replicate its microscopic appearance, but not its genomic architecture. Here we report a model that overcomes this barrier to authenticity. Methods Using a method developed to establish neural stem cell cultures, we investigated the effects of PDGF-AA on subventricular zone (SVZ) cells, one of the putative cells of origin of GBM. We microdissected SVZ tissue from p53-null and wild-type adult mice, cultured cells in media supplemented with PDGF-AA, and assessed cell viability, proliferation, genome stability, and tumorigenicity. Results Counterintuitive to its canonical role as a growth factor, we observed abrupt and massive cell death in PDGF-AA: wild-type cells did not survive, whereas a small fraction of null cells evaded apoptosis. Surviving null cells displayed attenuated proliferation accompanied by whole chromosome gains and losses. After approximately 100 days in PDGF-AA, cells suddenly proliferated rapidly, acquired growth factor independence, and became tumorigenic in immune-competent mice. Transformed cells had an oligodendrocyte precursor-like lineage marker profile, were resistant to platelet derived growth factor receptor alpha inhibition, and harbored highly abnormal karyotypes similar to human GBM. Conclusion This model associates genome instability in neural progenitor cells with chronic exposure to PDGF-AA and is the first to approximate the genomic landscape of human GBM and the first in which the earliest phases of the disease can be studied directly.


1989 ◽  
Vol 9 (10) ◽  
pp. 4473-4478 ◽  
Author(s):  
W J Fantl ◽  
J A Escobedo ◽  
L T Williams

The wild-type and two mitogenic-defective mutants of the type beta receptor for platelet-derived growth factor (PDGF) were expressed in Chinese hamster ovary cells. In the first mutant, delta Ki, 82 of 104 amino acids in the kinase insert region were deleted. This mutant was recently reported to be defective in mediating DNA synthesis. In the second mutant, Y825F, tyrosine 825 was converted to phenylalanine by a point mutation. We report here that this mutant is also defective in mediating PDGF-stimulated DNA synthesis. Both mutants were capable of eliciting many of the early responses to PDGF, including receptor autophosphorylation. However, neither mutant was capable of undergoing PDGF-stimulated change in receptor conformation or of phosphorylating exogenous substrate in an in vitro assay. These data suggest that changes in receptor conformation and efficient utilization of specific tyrosine kinase substrates are important for the stimulation of cell proliferation of PDGF and that phosphorylation of tyrosine 825 may be involved in signal transduction.


2008 ◽  
Vol 29 (3) ◽  
pp. 881-891 ◽  
Author(s):  
Anne Moenning ◽  
Richard Jäger ◽  
Angela Egert ◽  
Wolfram Kress ◽  
Eva Wardelmann ◽  
...  

ABSTRACT The development and growth of the skull is controlled by cranial sutures, which serve as growth centers for osteogenesis by providing a pool of osteoprogenitors. These osteoprogenitors undergo intramembranous ossification by direct differentiation into osteoblasts, which synthesize the components of the extracellular bone matrix. A dysregulation of osteoblast differentiation can lead to premature fusion of sutures, resulting in an abnormal skull shape, a disease called craniosynostosis. Although several genes could be linked to craniosynostosis, the mechanisms regulating cranial suture development remain largely elusive. We have established transgenic mice conditionally expressing an autoactivated platelet-derived growth factor receptor α (PDGFRα) in neural crest cells (NCCs) and their derivatives. In these mice, premature fusion of NCC-derived sutures occurred at early postnatal stages. In vivo and in vitro experiments demonstrated enhanced proliferation of osteoprogenitors and accelerated ossification of osteoblasts. Furthermore, in osteoblasts expressing the autoactivated receptor, we detected an upregulation of the phospholipase C-γ (PLC-γ) pathway. Treatment of differentiating osteoblasts with a PLC-γ-specific inhibitor prevented the mineralization of synthesized bone matrix. Thus, we show for the first time that PDGFRα signaling stimulates osteogenesis of NCC-derived osteoblasts by activating the PLC-γ pathway, suggesting an involvement of this pathway in the etiology of human craniosynostosis.


2007 ◽  
Vol 27 (10) ◽  
pp. 2142-2149 ◽  
Author(s):  
Peetra U. Magnusson ◽  
Camilla Looman ◽  
Aive Åhgren ◽  
Yan Wu ◽  
Lena Claesson-Welsh ◽  
...  

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