Platelet-derived Growth Factor Receptor Research Articles

Platelet-derived growth factor receptor beta is required for embryonic specification and confinement of the adult white adipose lineage

White adipose tissue (WAT) development and adult homeostasis rely on distinct adipocyte progenitor cells (APCs). While adult APCs are defined early during embryogenesis and generate adipocytes after WAT organogenesis, the mechanisms underlying adult adipose lineage determination and preservation remain undefined. Here, we uncover a critical role for platelet-derived growth factor receptor beta (Pdgfrβ) in identifying the adult APC lineage. Without Pdgfrβ, APCs lose their adipogenic competency to incite fibrotic tissue replacement and inflammation. Through lineage tracing analysis, we reveal that the adult APC lineage is lost and develops into macrophages when Pdgfrβ is deleted embryonically. Moreover, to maintain the APC lineage, Pdgfrβ activation stimulates p38/MAPK phosphorylation to promote APC proliferation and maintains the APC state by phosphorylating peroxisome proliferator activated receptor gamma (Pparγ) at serine 112. Together, our findings identify a role for Pdgfrβ acting as a rheostat for adult adipose lineage confinement to prevent unintended lineage switches.

The novel roles of YULINK in the migration, proliferation and glycolysis of pulmonary arterial smooth muscle cells: implications for pulmonary arterial hypertension

BackgroundAbnormal remodeling of the pulmonary vasculature, characterized by the proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) along with dysregulated glycolysis, is a pathognomonic feature of pulmonary arterial hypertension (PAH). YULINK (MIOS, Entrez Gene: 54468), a newly identified gene, has been recently shown to possess pleiotropic physiologic functions. This study aims to determine novel roles of YULINK in the regulation of PAH-related pathogenesis, including PASMC migration, proliferation and glycolysis.ResultsOur results utilized two PAH-related cell models: PASMCs treated with platelet-derived growth factor (PDGF) and PASMCs harvested from monocrotaline (MCT)-induced PAH rats (PAH-PASMCs). YULINK modulation, either by knockdown or overexpression, was found to influence PASMC migration and proliferation in both models. Additionally, YULINK was implicated in glycolytic processes, impacting glucose uptake, glucose transporter 1 (GLUT1) expression, hexokinase II (HK-2) expression, and pyruvate production in PASMCs. Notably, YULINK and GLUT1 were observed to colocalize on PASMC membranes under PAH-related pathogenic conditions. Indeed, increased YULINK expression was also detected in the pulmonary artery of human PAH specimen. Furthermore, YULINK inhibition led to the suppression of platelet-derived growth factor receptor (PDGFR) and the phosphorylation of focal adhesion kinase (FAK), phosphoinositide 3-kinase (PI3K), and protein kinase B (AKT) in both cell models. These findings suggest that the effects of YULINK are potentially mediated through the PI3K-AKT signaling pathway.ConclusionsOur findings indicate that YULINK appears to play a crucial role in the migration, proliferation, and glycolysis in PASMCs and therefore positioning it as a novel promising therapeutic target for PAH.

The synthetic routes of sorafenib and its applications on hepatocellular carcinoma

Cancer stands as the second leading cause of global mortality, with a staggering one in five individuals worldwide facing a cancer diagnosis in their lifetime. Addressing cancer prevention has emerged as a significant issue in the field of public health in the 21st century. Hepatocellular carcinoma (HCC) - the primary liver cancer type - not only ranks as one of the top five most frequent cancers globally, but also distressingly represents the fourth leading cause of cancer-related deaths. Notably, it claims the top spot in cancer-related mortality worldwide. Hepatocellular carcinoma is characterized by its high incidence, swift progression, recurrent nature, proclivity for metastasis, and distressingly high mortality rate. A significant proportion of cases trace a three-step path, hepatitis B infection leading to cirrhosis culminating in hepatocellular carcinoma. Sorafenib, a multi-targeted kinase inhibitor, offers promise in combatting this formidable adversary. It works by inhibiting key targets like vascular endothelial growth factor receptors (VEGFR1, VEGFR2, VEGFR3), platelet-derived growth factor receptor (PDGFR-), and RAF family kinases, which contributes to its healing effects. This article delves into the synthetic pathway of sorafenib, elucidating its impactful role in cancer treatment, and expounds on its advantageous attributes.

Application of sunitinib in cancer treatment and analysis of its synthetic route

Sunitinib, also known as the free base of sunitinib malate, is an innovative oral agent used in the treatment of tumors. It functions by inhibiting various members of the receptor tyrosine kinase (RTK) family, which possess a split kinase structural domain. These members include vascular endothelial growth factor receptors (VEGFR) 1, 2, and 3, platelet-derived growth factor receptors (PDGFR) and , stem cell factor receptors, FMS-like tyrosine kinase 3, colony-stimulating factor 1 receptor, and BCR/ABL fusion genes. This paper briefly introduces the research background, pharmacological activity and toxicity of sunitinib, sorting out the incidence and pathogenesis of the diseases it is targeted to treat, and its regulatory mechanism in treating the diseases, etc., summarising several synthetic routes of sunitinib researched by the previous researchers, and at the same time analysing and evaluating the synthetic routes and suggesting the synthetic routes, summing up and proposing the outlook of its subsequent research contents and directions, providing references and help to the research on sunitinib afterward.

From nature to cancer therapy: Evaluating the Streptomyces clavuligerus secondary metabolites for potential protein kinase inhibitors.

The study aimed to evaluate the antioxidant, protein kinase inhibitory (PKIs) potential, cytotoxicity activity of Streptomyces clavuligerus extract. DPPH assay revealed a robust free radical scavenging capacity (IC50 28.90 ± 0.24 µg/mL) of organic extract with a maximum inhibition percentage of 61 ± 1.04%. PKIsassay revealed the formation of a whitish bald zone by S. clavuligerus extracts which indicates the presence of PKIs. The cytotoxicity activity of organic fraction of extract through Sulforhodamine B assay on MCF-7, Hop-62, SiHa, and PC-3 cell lines demonstrated the lowest GI50 value against the MCF-7 cell line followed by the PC-3 cell line, showing potent growth inhibitory potential against human breast cancer and human prostate cancer cell line. HR-LCMS analysis identified multiple secondary metabolites from the organic and aqueous extracts of S. clavuligerus when incubated at 30°C under 200 rpm for 3 days. All the secondary metabolites were elucidated for their potential to inhibit RTKs by molecular docking, molecular dynamic simulation, MM/GBSA calculations, and free energy approach. It revealed the superior inhibitory potential of epirubicin (Epi) and dodecaprenyl phosphate-galacturonic acid (DPGA) against fibroblast growth factors receptor (FGFR). Epi also exhibited excellent inhibitory activity against the platelet-derived growth factor receptor (PDGFR), while DPGA effectively inhibited the vascular endothelial growth factor receptor.Additionally, the presence Epiin S. clavuligerus extract was validated through the HPLC technique. Thus, our findings highlight a superior inhibitory potential of Epiagainst FGFR and PDGFR RTKs than the FDA-approved drug.

Abstract C158: Predicting TKI responses in PDGFRA-mutant gastrointestinal stromal tumor

Abstract Gastrointestinal stromal tumor (GIST) is the most common sarcoma and frequently harbor oncogenic mutations in the receptor tyrosine kinases KIT or platelet derived growth factor receptor alpha (PDGFRA). Imatinib, a type II tyrosine kinase inhibitor (TKI), can successfully treat many KIT-mutant GIST. Yet, it is generally regarded as less effective against PDGFRA-mutant GIST because patients with the most common mutation, exon 18 D842V, are clinically resistant to imatinib and other GIST type II TKIs. However, there are many other PDGFRA mutations reported in GIST whose imatinib sensitivity is unknown. We curated mutation data from a large cohort of PDGFRA-mutant GIST patients, and over 80% had exon 18 mutations. Many mutations clustered around residues 840-849 and included non-D842V point mutations or complex indels. We previously biochemically profiled some of these frequently observed mutations and showed that some were imatinib sensitive, and that sensitivity was dependent on the properties of the 842-codon residue. As modeling each clinically reported mutation is not feasible, we hypothesized that imatinib sensitivity of PDGFRA exon 18 mutations could be predicted based on the 842 residue. To test our hypothesis, we created individual Ba/F3 cell lines that expressed individual PDGFRA mutant kinases, with one cell line each for every amino acid substitution at the 842 residue. Cells underwent transformation limiting dilution assays and imatinib sensitivity was determined via immunoblotting for phosphorylated and total PDGFRA. We observed that 13 out of the 20 amino acids conferred imatinib sensitivity when in the 842-codon position. 7 out of 8 hydrophobic residues conferred imatinib resistance (IC50>150nM) and all amino acids from other classes (polar, negative charge, positive charge, special case) conferred sensitivity (IC50<150nM). Alanine conferred imatinib sensitivity, despite being hydrophobic. Previous studies describe that imatinib resistance seen in D842V patients is due to PDGFRA structural changes. Therefore, we are currently performing molecular simulations and drug docking studies with our mutant kinases to understand how changes at the 842 position effect kinase structure and imatinib binding. Our predictions will identify patients that would benefit from imatinib therapy, while identifying those that require avapritinib. Avapritinib was recently FDA-approved for first-line treatment of all PDGFRA exon 18 mutation GIST, although it was initially created to target D842V. In Europe, avapritinib is only approved for D842V patients. Identifying non-D842V patients that either require avapritinib or could benefit from imatinib is crucial, as current guidelines may suggest no treatment at all. Also, eligible patients treated with imatinib first have additional treatment options if they progress, but this avenue is not available for those progressing on avapritinib. Using our work to support this paradigm shifting approach to optimize TKI treatment sequencing for PDGFRA-mutant GIST will transform patient care and clinical outcomes. Citation Format: Homma M Khosroyani, Ajia Town, Johanna Falkenhorst, Sebastian Bauer, Michael Heinrich. Predicting TKI responses in PDGFRA-mutant gastrointestinal stromal tumor [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C158.

Ovarian cancer relies on the PDGFRβ-fibronectin axis for tumorsphere formation and metastatic spread.

High-grade serous ovarian cancer (HGSOC) is the deadliest gynecological malignancy. The most common form of metastatic spread of HGSOC is transcoelomic dissemination. In this process, detached cells from the primary tumor aggregate as tumorspheres and promote the accumulation of peritoneal ascites. This represents an early event in HGSOC development and is indicative of poor prognosis. In this study, based on tumorspheres isolated from ascitic liquid samples from HGSOC patients, ovarian cancer spheroid 3D cultures, and in vivo models, we describe a key signal for tumorsphere formation in HGSOC. We report that platelet-derived growth factor receptor beta (PDGFRβ) is essential for fibronectin-mediated cell clustering of ovarian cancer cells into tumorspheres. This effect is mediated by the kinase NUAK family SNF1-like kinase 1 (NUAK1) and blocked by PDGFRβ pharmacological or genetic inhibition. In the absence of PDGFRβ, ovarian cancer cells can be provided with fibronectin by cancer-associated fibroblasts to generate chimeric spheroids. This work provides new insights that uncover potential targets to prevent peritoneal dissemination, the main cause of advanced disease in HGSOC patients.

PDGFRβ Activation Induced the Bovine Embryonic Genome Activation via Enhanced NFYA Nuclear Localization

Embryonic genome activation (EGA) is a critical step during embryonic development. Several transcription factors have been identified that play major roles in initiating EGA; however, this gradual and complex mechanism still needs to be explored. In this study, we investigated the role of nuclear transcription factor Y subunit A (NFYA) in bovine EGA and bovine embryonic development and its relationship with the platelet-derived growth factor receptor-β (PDGFRβ) by using a potent selective activator (PDGF-BB) and inhibitor (CP-673451) of PDGF receptors. Activation and inhibition of PDGFRβ using PDGF-BB and CP-673451 revealed that NFYA expression is significantly (p < 0.05) affected by the PDGFRβ. In addition, PDGFRβ mRNA expression was significantly increased (p < 0.05) in the activator group and significantly decreased (p < 0.05) in the inhibitor group when compared with PDGFRα. Downregulation of NFYA following PDGFRβ inhibition was associated with the expression of critical EGA-related genes, bovine embryo development rate, and implantation potential. Moreover, ROS and mitochondrial apoptosis levels and expression of pluripotency-related markers necessary for inner cell mass development were also significantly (p < 0.05) affected by the downregulation of NFYA while interrupting trophoblast cell (CDX2) differentiation. In conclusion, the PDGFRβ-NFYA axis is critical for bovine embryonic genome activation and embryonic development.

Effects of electroacupuncture on the microvascular structure and related protein expression in the hippocampus of vascular dementia rats.

To explore the effect of electroacupuncture (EA) at "Baihui" (GV20) and "Shenting" (GV24) on the microvascular structure and related protein expression in the hippocampus of vascular dementia (VD) rat model, and to investigate the mechanism of EA in the treatment of VD. A total of 24 SD rats were randomly divided into sham operation, model, EA, and oxiracetam groups, with 6 rats in each group. Multiple cerebral infarction method was used to establish VD model. In the EA group, EA was applied to GV20 and GV24 for 30 min, once daily for 14 days. Rats in the oxiracetam group were treated with oxiracetam (50 mg/kg) by intraperitoneal injection, and the course of treatment was the same as that in the EA group. Learning and memory ability were evaluated by using Morris water maze test and new object recognition experiment. The cerebral blood flow was detected by laser doppler. The microvascular structure in the hippocampus was observed by transmission electron microscopy. The expression of vascular structure related proteins of platelet-derived growth factor receptor (PDGFR)-β, platelet endothelial cell adhesion molecule-1(CD31), neural cadherin N-Cadherin, Zonula occludens protein-1(ZO-1) in the hippocampus were measured by Western blot. Compared with the sham operation group, the rats in the model group had a significant increase in time of first crossing the platform, a significant decrease in the number of crossing platform and the new object preference index (P<0.05), a significant decrease in cerebral blood flow (P<0.05), and a significant increase in the brain weight (P<0.05). The structure boundary of pericyte and endothelial cells in the microvessels of the hippocampal CA1 area of model group was blurred, accompanied by obvious edema around the vessels and the reduction of tight junctions. The protein expression levels of PDGFR-β, CD31, N-Cadherin, ZO-1 were significantly decreased in the model group compared with those in the sham operation group (P<0.05). Compared with the model group, the time of first crossing the platform of rats in the EA and oxiracetam group was shortened, the number of crossing platform were increased (P<0.05), the cerebral blood flow was increased (P<0.05), the brain weight was decreased (P<0.05), the morphology and structure of pericyte and endothelial cells in the microvessels of hippocampal CA1 area were intact, accompanied by the increase of tight junctions. Additionally, Compared with the model group, the EA group had a significant increase in the new object preference index (P<0.05), the protein expression levels of PDGFR-β, CD31, ZO-1 in the EA group were increased (P<0.05), and the expression of PDGFR-β, N-Cadherin, ZO-1 in the oxiracetam group were increased (P<0.05). EA at GV20 and GV24 can improve the learning and memory ability of VD rats, and the mechanism may be related to the repair of microvascular structures and improvement of cerebral blood flow.

Unveiling Cellular Diversity in the Buffalo Corneal Stroma: Insights into Telocytes and Keratocytes Using Light Microscope, Transmission Electron Microscope, and Immunofluorescence Analysis.

Telocytes and keratocytes are important cells that maintain the structure and function of the cornea. The buffalo cornea, known for its resilience in harsh conditions, has not been extensively studied regarding the presence and role of telocytes and keratocytes. We used light microscopy, transmission electron microscopy (TEM), and immunofluorescence assays with platelet-derived growth factor receptor alpha (PDGFRα), CD34, and Vimentin markers to investigate their expression and localization in the cornea. TEM analysis confirmed the presence of spindle-shaped keratocytes with intercellular connections, while telocytes exhibited small spindle-shaped bodies with long, thin branches connecting to corneal keratocytes. Immunofluorescence findings showed that CD34 was more abundant near the endothelium, Vimentin was prominently expressed near the epithelium, and PDGFRα was uniformly distributed throughout the corneal stroma. Co-expression of CD34 and Vimentin, PDGFRα and Vimentin, as well as CD34 and PDGFRα, was observed in keratocytes and telocytes within the stroma, indicating the potential presence of mesenchymal cells. These results suggest the involvement of telocytes and keratocytes in corneal wound healing, transparency maintenance, and homeostasis. The co-expression of these markers highlights the critical role of telocytes and keratocytes in regulating corneal physiological functions, further enhancing our understanding of corneal biology in the buffalo model.

RhoGDI3 at the trans-Golgi network participates in NLRP3 inflammasome activation, VSMC phenotypic modulation, and neointima formation

Background and aimsThe pathological roles and mechanisms of Rho-specific guanine nucleotide dissociation inhibitor 3 (RhoGDI3) in vascular smooth muscle cell (VSMC) phenotypic modulation and neointima formation are currently unknown. This study aimed to investigate how RhoGDI3 regulates the Nod-like receptor protein 3 (NLRP3) inflammasome in platelet-derived growth factor-BB (PDGF-BB)-induced neointima formation. MethodsFor in vitro assays, human aortic VSMCs (HA-VSMCs) were transfected with pcDNA3.1-GDI3 and RhoGDI3 siRNA to overexpress and knockdown RhoGDI3, respectively. HA-VSMCs were also treated with an NLRP3 inhibitor (CY-09) or agonist (NSS). Protein transcription and expression, cell proliferation and migration, Golgi morphology, and protein binding and colocalization were measured. For the in vivo assays, balloon injury (BI) rats were injected with recombinant adenovirus carrying RhoGDI3 shRNA. Carotid arterial morphology, protein expression and colocalization, and activation of the NLRP3 inflammasome were measured. ResultsPDGF-BB treatment induced transcription and expression of RhoGDI3 through PDGF receptor αβ (PDGFRαβ) rather than PDGFRαα or PDGFRββ in HA-VSMCs. RhoGDI3 suppression blocked PDGF-BB-induced VSMC phenotypic transformation. In contrast, RhoGDI3 overexpression further promoted PDGF-BB-induced VSMC dedifferentiation. The in vivo results also confirmed that RhoGDI3 expressed in VSMCs participated in neointima formation and muscle fiber and collagen deposition caused by balloon injury. In addition, PDGF-BB increased binding of RhoGDI3 to NLRP3 and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) at the trans-Golgi membrane, which depended on the normal Golgi network. However, recruitment of NLRP3 and ASC to the trans-Golgi network after PDGF-BB treatment was independent of RhoGDI3. Moreover, RhoGDI3 knockdown significantly inhibited ASC expression and NLRP3 inflammasome assembly and activation and reduced NLRP3 protein stability in PDGF-BB-treated HA-VSMCs. Inhibiting NLRP3 effectively prevented PDGF-BB-induced VSMC phenotypic modulation, and an NLRP3 agonist reversed the decline in VSMC phenotypic transformation caused by RhoGDI3 knockdown. Furthermore, RhoGDI3 suppression reduced the protein levels and assembly of NLRP3 and ASC, and the activation of the NLRP3 inflammasome in VSMCs in a rat balloon injury model. ConclusionsThe results of this study reveal a novel mechanism through which RhoGDI3 regulates VSMC phenotypic modulation and neointima formation by activating the NLRP3 inflammasome.

Reprogramming the pancreatic cancer stroma and immune landscape by a silicasome nanocarrier delivering nintedanib, a protein tyrosine kinase inhibitor

The prevailing desmoplastic stroma and immunosuppressive microenvironment within pancreatic ductal adenocarcinoma (PDAC) pose substantial challenges to therapeutic intervention. Despite the potential of protein tyrosine kinase (PTK) inhibitors in mitigating the desmoplastic stromal response and enhancing the immune milieu, their efficacy is curtailed by suboptimal pharmacokinetics (PK) and insufficient tumor penetration. To surmount these hurdles, we have pioneered a novel strategy, employing lipid bilayer-coated mesoporous silica nanoparticles (termed "silicasomes") as a carrier for the delivery of Nintedanib. Nintedanib, a triple PTK inhibitor that targets vascular endothelial growth factor, platelet-derived growth factor and fibroblast growth factor receptors, was encapsulated in the pores of silicasomes via a remote loading mechanism for weak bases. This innovative approach not only enhanced pharmacokinetics and intratumor drug concentrations but also orchestrated a transformative shift in the desmoplastic and immune landscape in a robust orthotopic KRAS-mediated pancreatic carcinoma (KPC) model. Our results demonstrate attenuation of vascular density and collagen content through encapsulated Nintedanib treatment, concomitant with significant augmentation of the CD8+/FoxP3+ T-cell ratio. This remodeling was notably correlated with tumor regression in the KPC model. Strikingly, the synergy between encapsulated Nintedanib and anti-PD-1 immunotherapy further potentiated the antitumor effect. Both free and encapsulated Nintedanib induced a transcriptional upregulation of PD-L1 via the extracellular signal-regulated kinase (ERK) pathway. In summary, our pioneering approach involving the silicasome carrier not only improved antitumor angiogenesis but also profoundly reshaped the desmoplastic stromal and immune landscape within PDAC. These insights hold excellent promise for the development of innovative combinatorial strategies in PDAC therapy.

Anti-fibrotic effects of nintedanib on lung fibroblasts derived from patients with Progressive Fibrosing Interstitial Lung Diseases (PF-ILDs)

The tyrosine kinase inhibitor nintedanib has been recently approved for the treatment of Interstitial Lung Diseases (ILDs) that manifest a progressive fibrosis phenotype other than Idiopathic pulmonary Fibrosis (IPF).Nintedanib reduces the development of lung fibrosis in various animal models resembling features of PF-ILD and in vitro, it inhibits the fibrosing phenotype of human lung fibroblasts (HLFs) isolated from patients with IPF. To get insight on the cellular and molecular mechanisms that drive the clinical efficiency of nintedanib in patients with non-IPF PF-ILD, we investigated its effects on the fibrosing functions of HLFs derived from patients with PF-hypersensitivity pneumonitis (PF-HP, n = 7), PF-sarcoidosis (n = 5) and pleuroparenchymal fibroelastosis (PPFE, n = 4).HLFs were treated with nintedanib (10 nM-1 μM) and then stimulated with PDGF-BB (25–50 ng/ml) or TGF-β1 (1 ng/ml) for 24–72 h to assess proliferation and migration or differentiation.At nanomolar concentrations, nintedanib reduced the levels of PDGF receptor and ERK1/2 phosphorylation, the proliferation and the migration of PF-HP, PF-sarcoidosis and PPFE HLFs stimulated with PDGF-BB. Moreover, nintedanib also attenuates the myofibroblastic differentiation driven by TGF-β1 but only when it is used at 1 μM. The drug reduced the phosphorylation of SMAD2/3 and decreased the induction of collagen, fibronectin and α-smooth muscle actin expression induced by TGF-β1.In conclusion, our results demonstrate that nintedanib counteracts fundamental fibrosing functions of lung fibroblasts derived from patients with PF-HP, PF-sarcoidosis and PPFE, at concentrations previously reported to inhibit control and IPF HLFs. Such effects may contribute to its clinical benefit in patients suffering from these irreversible ILDs.

PDGFR-beta signaling mediates endogenous neurogenesis after postischemic neural stem/progenitor cell transplantation in mice

ABSTRACT Objective Although platelet-derived growth factor receptor (PDGFR)-β mediates the self-renewal and multipotency of neural stem/progenitor cells (NSPCs) in vitro and in vivo, its mechanisms of activating endogenous NSPCs following ischemic stroke still remain unproven. Methods The exogenous NSPCs were transplanted into the ischemic striatum of PDGFR-β conditionally neuroepithelial knockout (KO) mice at 24 h after transient middle cerebral artery occlusion (tMCAO). 5-Bromo-2’-deoxyuridine (BrdU) was intraperitoneally injected to label the newly formed endogenous NSPCs. Infarction volume was measured, and behavioral tests were performed. In the subventricular zone (SVZ), proliferation of endogenous NSPCs was tested, and synapse formation and expression of nutritional factors were measured. Results Compared with control mice, KO mice showed larger infarction volume, delayed neurological recovery, reduced numbers of BrdU positive cells, decreased expression of neurogenic factors (including neurofilament, synaptophysin, and brain-derived neurotrophic factor), and decreased synaptic regeneration in SVZ after tMCAO. Moreover, exogenous NSPC transplantation significantly alleviated neurologic dysfunction, promoted neurogenesis, increased expression of neurologic factors, and diminished synaptic deformation in SVZ of FL mice after tMCAO but had no beneficial effect in KO mice. Conclusion PDGFR-β signaling may promote activation of endogenous NSPCs after postischemic NSPC transplantation, and thus represents a novel potential regeneration-based therapeutic target.

Fgf2 and Ptpn11 play a role in cerebral injury caused by sevoflurane anesthesia.

Sevoflurane is a new inhaled anesthetic, which has better physical properties than the existing inhalational anesthetics, rapid induction, less tissue uptake, and faster recovery. Sevoflurane can directly dilators cerebral blood vessels and increase cerebral blood flow, but it also reduces cerebral oxygen metabolism rate, thereby reducing cerebral blood flow. However, the role of Fgf2 and Ptpn11 in cerebral injury caused by sevoflurane anesthesia remains unclear. The sevoflurane anesthesia brain tissue datasets GSE139220 and GSE141242 were downloaded from gene expression omnibus (GEO). Differentially expressed genes (DEGs) were screened and weighted gene co-expression network analysis (WGCNA) was performed. Construction and analysis of protein-protein interaction (PPI) Network. Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG), comparative toxicogenomics database (CTD) were performed. A heat map of gene expression was drawn. TargetScan was used to screen miRNAs regulating DEGs. 500 DEGs were identified. According to GO, in Biological Process analysis, they were mainly enriched in response to hypoxia, blood vessel development, inner ear development, neural tube closure, and aging. In Cellular Component (CC), they were mainly enriched in plasma membrane, integral component of membrane, and basal lamina. In Molecular Function (MF), they were mainly associated with protein binding, Wnt-activated receptor activity, and organic anion transmembrane transporter activity. In the KEGG analysis, they were mainly enriched in proteoglycans in cancer, pathways in cancer, transcriptional misregulation in cancer, basal cell carcinoma, thyroid hormone signaling pathway. In the Metascape enrichment analysis, the GO enrichment items revealed upregulated regulation of vascular endothelial cell proliferation, platelet-derived growth factor receptor signaling pathway, inner ear development, and response to hypoxia. A total of 20 modules were generated. Gene Expression Heatmap showed that the core genes (Fgf2, Pdgfra, Ptpn11, Slc2a1) were highly expressed in sevoflurane anesthesia brain tissue samples. CTD Analysis showed that the 4 core genes (Fgf2, Pdgfra, Ptpn11, Slc2a1) were associated with neurodegenerative diseases, brain injuries, memory disorders, cognitive disorders, neurotoxicity, drug-induced abnormalities, neurological disorders, developmental disorders, and intellectual disabilities. Fgf2 and Ptpn11 are highly expressed in brain tissue after sevoflurane anesthesia, higher the expression level of Fgf2 and Ptpn11, worse the prognosis.

Mutation in PDGFRbeta: a potential new pathogenic variant for mitral valve prolapse

Abstract Background Mitral valve prolapse (MVP) due to myxomatous degeneration is characterized by familial clustering, but few pathogenic genes have been identified. In a genetic screening program for MVP patients, we identified a platelet-derived growth factor receptor β (PDGFRβ)-E162K missense variant in a family with a bi-leaflet MVP phenotype in four affected family members. PDGFRβ is a receptor tyrosine kinase, which plays an important role in vascular development. Purpose In this study, we investigated whether the E162K substitution in PDGFRβ could lead to mitral valve abnormalities. Methods To assess the functional effects of the missense variant, proliferation and migration assays were performed using HeLa cells overexpressing wild-type (WT) or mutant PDGFRβ. Immunostainings were performed to determine PDGFRβ expression in the diseased valves from a family member undergoing surgical operation and from additional patients operated for MVP. Mouse models were created with the mouse equivalent of the human PDGFRβ-E162K variant (PDGFRβ-E161K) using CRISPR/CAS9. The variant was not lethal and a total of 12 homozygous PDGFRβ-E161K-/- mice, 11 heterozygous PDGFRβ-E161K+/- mice, and 7 WT mice were subjected to transthoracic echocardiography. In addition, histology was performed in all 30 mice to detect potential valvular defects. Results Stimulated HeLa cells expressing PDGFRβ-E162K showed reduced proliferation and migration, suggesting a loss of function of the mutant receptor. PDGFRβ was expressed in human diseased mitral valves. Echocardiographic evaluation revealed a significant larger mitral valve annulus diameter in both PDGFRβ-E161K+/- and PDGFRβ-E161K-/- compared to WT (WT: 1.97 mm; PDGFRβ-E161K+/-:2.13, p=0.031; PDGFRβ-E161K-/-: 2.42 mm, p&amp;lt;0.0001). Histological data in PDGFRβ-E161K-/- mice showed significant leaflet thickening in the free edge (FE) of the posterior mitral valve leaflet (PMVL) compared to WT (WT: 72.34 ɥm; PDGFRβ-E161K-/-: 109.6 ɥm, p=0.040) and a larger leaflet area of the PMVL compared to WT (WT: 25280 ɥm²; PDGFRβ-E161K-/-: 44494 ɥm², p=0.020). Moreover, an altered organization of the extracellular matrix reminiscent of the myxomatous degeneration in MVP was observed. Conclusions The PDGFRβ-E162K variant is associated with familial MVP and alters the function of PDGFRβ. Mice harboring this mutation display mitral valve defects and can be used as a model for mitral valve disease.

Dipeptidyl Peptidase 4 Stimulation Induces Adipogenesis-Related Gene Expression of Adipose Stromal Cells.

Adipogenesis has emerged as a new therapeutic target for regulating metabolism and achieving anti-inflammatory and anti-atherosclerotic effects via the release of adiponectin. However, at present, the effects and mechanism of action of dipeptidyl peptidase 4 (DPP4) stimulation on adiponectin production and adipogenesis have not been clarified. Here, we investigated the effects of DPP4 stimulation with monocyte chemoattractant protein-1 (MCP-1) on platelet-derived growth factor receptor alpha (PDGFRα) expression in adipose tissue and blood adiponectin levels. Stromal vascular fractions (SVFs) purified from human subcutaneous adipose tissue and inguinal adipose tissue of obese and diabetic (Leprdb/db) mice were treated with 50 ng of MCP-1 and plasma from control (Lepr+/+) mice supplemented with 10 ng or 50 ng of MCP-1. Treatment of SVFs from human subcutaneous adipose tissues with 50 ng of MCP-1 significantly increased AdipoQ, DPP4, peroxisome proliferator-activated receptor gamma (PPARγ), fatty-acid-binding protein (FABP4), and SERBF1 mRNA expression. MCP-1-supplemented plasma increased adiponectin, CCAAT-Enhancer-binding protein alpha (C/EBPα), DPP4, IL-33, and PDGFRα mRNA expression and adiponectin and DPP4 protein expression, while decreasing the expression of IL-10 mRNA in SVFs compared with the levels in the plasma treatment group. MCP-1-supplemented plasma was shown to increase PPARγ, PPARγ2, adiponectin, DPP4, and FABP4 and decrease IL-10 mRNA expression in PDGFRα cells from adipose tissue. Meanwhile, MCP-1-supplemented plasma increased MCP-1, PDGFRα, TNFα, adiponectin, and IL-1β and decreased IL-10 and FOXP3 mRNA expression in DPP4 cells. Moreover, the injection of MCP-1-supplemented plasma into adipose tissue increased the proportion of DPP4+ cells among PDGFRα+ cells from adipose tissue and plasma adiponectin levels of Leprdb/db mice compared with the levels in the plasma injection group. Our results demonstrate that DPP4+ cells are important adipose progenitor cells. Stimulation of DPP4 with MCP-1 increases adipogenesis-related gene expression and the population of DPP4+ cells among PDGFRα+ cells in SVFs and blood adiponectin levels. DPP4 stimulation could be a novel therapy to increase local adipogenesis and systemic adiponectin levels.

The myocardium utilizes a platelet-derived growth factor receptor alpha (Pdgfra)-phosphoinositide 3-kinase (PI3K) signaling cascade to steer toward the midline during zebrafish heart tube formation.

Coordinated cell movement is a fundamental process in organ formation. During heart development, bilateral myocardial precursors collectively move toward the midline (cardiac fusion) to form the primitive heart tube. Extrinsic influences such as the adjacent anterior endoderm are known to be required for cardiac fusion. We previously showed however, that the platelet-derived growth factor receptor alpha (Pdgfra) is also required for cardiac fusion (Bloomekatz et al., 2017). Nevertheless, an intrinsic mechanism that regulates myocardial movement has not been elucidated. Here, we show that the phosphoinositide 3-kinase (PI3K) intracellular signaling pathway has an essential intrinsic role in the myocardium directing movement toward the midline. In vivo imaging further reveals midline-oriented dynamic myocardial membrane protrusions that become unpolarized in PI3K-inhibited zebrafish embryos where myocardial movements are misdirected and slower. Moreover, we find that PI3K activity is dependent on and interacts with Pdgfra to regulate myocardial movement. Together our findings reveal an intrinsic myocardial steering mechanism that responds to extrinsic cues during the initiation of cardiac development.

P-241 - Novel 68Ga-labelled nanobody for imaging of platelet-derived growth factor receptor beta

P-241 - Novel 68Ga-labelled nanobody for imaging of platelet-derived growth factor receptor beta

Concurrent PTEN and PDGFRB Alterations Characterize Storiform Collagenoma.

Storiform collagenoma is a rare mesenchymal skin tumor that is composed of thickened collagen bundles arranged in a characteristic storiform pattern with a relatively hypocellular CD34-positive spindle cell component. Storiform collagenoma is most often sporadic, but multiple lesions can occur in Cowden syndrome, which is characterized by germline alterations in PTEN (phosphatase and tensin homolog) on chromosome 10. Here, we investigated the molecular pathogenesis of storiform collagenoma using a targeted next-generation DNA sequencing platform, including 5 sporadic cases and one case associated with Cowden syndrome. Recurrent PTEN alterations were identified in all cases, with biallelic PTEN inactivation observed in the case associated with Cowden syndrome and one sporadic case. Unexpectedly, we also identified recurrent activating mutations in the platelet-derived growth factor receptor beta (PDGFRB) gene. This included a missense substitution in the D5 Ig-like domain of PDGFRB in the Cowden syndrome-associated case. In addition, we report missense alterations in the juxtamembrane domain of PDGFRB in 4 of 5 (80%) sporadic cases, including mutations that have been previously described in sporadic myofibroma and myopericytoma. Therefore, we confirm the neoplastic nature of storiform collagenoma, we expand the spectrum of reported PDGFRB alterations in mesenchymal tumors and we suggest a possible collaborative role for PTEN and PDGFRB in the pathogenesis of storiform collagenoma.