Induced pluripotent stem cell derived pericytes respond to mediators of proliferation and contractility.

BACKGROUND: Pericytes are multifunctional contractile cells that reside on capillaries. Pericytes are critical regulators of cerebral blood flow and blood-brain barrier function, and pericyte dysfunction may contribute to the pathophysiology of human neurological diseases including Alzheimers disease, multiple sclerosis, and stroke. Induced pluripotent stem cell (iPSC)-derived pericytes (iPericytes) are a promising tool for vascular research. However, it is unclear how iPericytes functionally compare to primary human brain vascular pericytes (HBVPs). METHODS: We differentiated iPSCs into iPericytes of either the mesoderm or neural crest lineage using established protocols. We compared iPericyte and HBVP morphologies, quantified gene expression by qPCR and bulk RNA sequencing, and visualised pericyte protein markers by immunocytochemistry. To determine whether the gene expression of neural crest iPericytes, mesoderm iPericytes or HBVPs correlated with their functional characteristics in vitro, we quantified EdU incorporation following exposure to the key pericyte mitogen, platelet derived growth factor (PDGF)-BB and, contraction and relaxation in response to the vasoconstrictor endothelin-1 or vasodilator adenosine, respectively. RESULTS: iPericytes were morphologically similar to HBVPs and expressed canonical pericyte markers. However, iPericytes had 1864 differentially expressed genes compared to HBVPs, while there were 797 genes differentially expressed between neural crest and mesoderm iPericytes. Consistent with the ability of HBVPs to respond to PDGF-BB signalling, PDGF-BB enhanced and a PDGF receptor-beta inhibitor impaired iPericyte proliferation. Administration of endothelin-1 led to iPericyte contraction and adenosine led to iPericyte relaxation, of a magnitude similar to the response evoked in HBVPs. We determined that neural crest iPericytes were less susceptible to PDGFR beta inhibition, but responded most robustly to vasoconstrictive mediators. CONCLUSIONS: iPericytes express pericyte-associated genes and proteins and, exhibit an appropriate physiological response upon exposure to a key endogenous mitogen or vasoactive mediators. Therefore, the generation of functional iPericytes would be suitable for use in future investigations exploring pericyte function or dysfunction in neurological diseases.

Platelet-derived growth factor receptor ß-targeted positron emission tomography imaging for the noninvasive monitoring of liver fibrosis.

PURPOSE: Noninvasive quantifying activated hepatic stellate cells (aHSCs) by molecular imaging is helpful for assessing disease progression and therapeutic responses of liver fibrosis. Our purpose is to develop platelet-derived growth factor receptor ß (PDGFRß)-targeted radioactive tracer for assessing liver fibrosis by positron emission tomography (PET) imaging of aHSCs. METHODS: Comparative transcriptomics, immunofluorescence staining and flow cytometry were used to evaluate PDGFRß as biomarker for human aHSCs and determine the correlation of PDGFRß with the severity of liver fibrosis. The high affinity affibody for PDGFRß (ZPDGFRß) was labeled with gallium-68 (68Ga) for PET imaging of mice with carbon tetrachloride (CCl4)-induced liver fibrosis. Binding of the [68Ga]Ga-labeled ZPDGFRß ([68Ga]Ga-DOTA-ZPDGFRß) for aHSCs in human liver tissues was measured by autoradiography. RESULTS: PDGFRß overexpressed in aHSCs was highly correlated with the severity of liver fibrosis in patients and CCl4-treated mice. The 68Ga-labeled ZPDGFRß affibody ([68Ga]Ga-DOTA-ZPDGFRß) showed PDGFRß-dependent binding to aHSCs. According to the PET imaging, hepatic uptake of [68Ga]Ga-DOTA-ZPDGFRß increased with the accumulation of aHSCs and collagens in the fibrotic livers of mice. In contrast, hepatic uptake of [68Ga]Ga-DOTA-ZPDGFRß decreased with spontaneous recovery or treatment of liver fibrosis, indicating that the progression and therapeutic responses of liver fibrosis in mice could be visualized by PDGFRß-targeted PET imaging. [68Ga]Ga-DOTA-ZPDGFRß also bound human aHSCs and visualized fibrosis in patient-derived liver tissues. CONCLUSIONS: PDGFRß is a reliable biomarker for both human and mouse aHSCs. PDGFRß-targeted PET imaging could be used for noninvasive monitoring of liver fibrosis in mice and has great potential for clinical translation.

Platelet-derived Growth Factor Activates Pericytes in the Microvessels of Chronic Subdural Hematoma Outer Membranes.

Angiogenesis is one of the growth mechanisms of chronic subdural hematoma (CSDH). Pericytes have been implicated in the capillary sprouting during angiogenesis and are involved in brain ischemia and diabetic retinopathy. This study examined the pericyte expressions in CSDH outer membranes obtained during trepanation surgery. Eight samples of CSDH outer membranes and 35 samples of CSDH fluid were included. NG2, N-cadherin, VE-cadherin, Tie-2, endothelial nitric oxide synthase (eNOS), platelet-derived growth factor (PDGF) receptor-ß (PDGFR-ß), a well-known marker of pericytes, phosphorylated PDGFR-ß at Tyr751, and ß-actin expressions, were examined using western blot analysis. PDGFR-ß, N-cadherin, and Tie-2 expression levels were also examined using immunohistochemistry. The concentrations of PDGF-BB in CSDH fluid samples were measured using enzyme-linked immunosorbent assay kits. NG2, N-cadherin, VE-cadherin, Tie-2, eNOS, PDGFR-ß, and eNOS expressions in CSDH outer membranes were confirmed in all cases. Furthermore, phosphorylated PDGFR-ß at Tyr751 was also detected. In addition, PDGFR-ß, N-cadherin, and Tie-2 expressions were localized to the endothelial cells of the vessels within CSDH outer membranes by immunohistochemistry. The concentration of PDGF-BB in CSDH fluids was significantly higher than that in cerebrospinal fluid. These findings indicate that PDGF activates pericytes in the microvessels of CSDH outer membranes and suggest that pericytes are crucial in CSDH angiogenesis through the PDGF/PDGFR-ß signaling pathway.

Retinal inflammation in murine models of type 1 and type 2 diabetes with diabetic retinopathy.

AIMS/HYPOTHESIS: The loss of pericytes surrounding the retinal vasculature in early diabetic retinopathy underlies changes to the neurovascular unit that lead to more destructive forms of the disease. However, it is unclear which changes lead to loss of retinal pericytes. This study investigated the hypothesis that chronic increases in one or more inflammatory factors mitigate the signalling pathways needed for pericyte survival. METHODS: Loss of pericytes and levels of inflammatory markers at the mRNA and protein levels were investigated in two genetic models of diabetes, Ins2Akita/+ (a model of type 1 diabetes) and Leprdb/db (a model of type 2 diabetes), at early stages of diabetic retinopathy. In addition, changes that accompany gliosis and the retinal vasculature were determined. Finally, changes in retinal pericytes chronically incubated with vehicle or increasing amounts of IFNγ were investigated to determine the effects on pericyte survival. The numbers of pericytes, microglia, astrocytes and endothelial cells in retinal flatmounts were determined by immunofluorescence. Protein and mRNA levels of inflammatory factors were determined using multiplex ELISAs and quantitative reverse transcription PCR (qRT-PCR). The effects of IFNγ on the murine retinal pericyte survival-related platelet-derived growth factor receptor ß (PDGFRß) signalling pathway were investigated by western blot analysis. Finally, the levels of cell death-associated protein kinase C isoform delta (PKCδ) and cleaved caspase 3 (CC3) in pericytes were determined by western blot analysis and immunocytochemistry. RESULTS: The essential findings of this study were that both type 1 and 2 diabetes were accompanied by a similar progression of retinal pericyte loss, as well as gliosis. However, inflammatory factor expression was dissimilar in the two models of diabetes, with peak expression occurring at different ages for each model. Retinal vascular changes were more severe in the type 2 diabetes model. Chronic incubation of murine retinal pericytes with IFNγ decreased PDGFRß signalling and increased the levels of active PKCδ and CC3. CONCLUSIONS/INTERPRETATION: We conclude that retinal inflammation is involved in and sustains pericyte loss as diabetic retinopathy progresses. Moreover, IFNγ plays a critical role in reducing pericyte survival in the retina by reducing activation of the PDGFRß signalling pathway and increasing PKCδ levels and pericyte apoptosis.

Changes in CSF sPDGFRß level and their association with blood-brain barrier breakdown in Alzheimer's disease with or without small cerebrovascular lesions.

BACKGROUND: CSF-soluble platelet-derived growth factor receptor beta (sPDGFRß) is closely associated with pericyte damage. However, the changes in CSF sPDGFRß levels and their role in blood-brain barrier (BBB) leakage at different stages of Alzheimer's disease (AD), with or without cerebral small vessel disease (CSVD) burden, remain unclear. METHODS: A total of 158 individuals from the China Aging and Neurodegenerative Disorder Initiative cohort were selected, including 27, 48, and 83 individuals with a clinical dementia rating (CDR) score of 0, 0.5, and 1-2, respectively. CSF total tau, phosphorylated tau181 (p-tau181), Aß40, and Aß42 were measured using the Simoa assay. Albumin and CSF sPDGFRß were measured by commercial assay kits. CSVD burden was assessed by magnetic resonance imaging. RESULTS: CSF sPDGFRß was the highest level in the CDR 0.5 group. CSF sPDGFRß was significantly correlated with the CSF/serum albumin ratio (Q-alb) in the CDR 0-0.5 group (ß = 0.314, p = 0.008) but not in the CDR 1-2 group (ß = - 0.117, p = 0.317). In the CDR 0-0.5 group, CSF sPDGFRß exhibited a significant mediating effect between Aß42/Aß40 levels and Q-alb (p = 0.038). Q-alb, rather than CSF sPDGFRß, showed a significant difference between individuals with or without CSVD burden. Furthermore, in the CDR 0.5 group, CSF sPDGFRß was higher in subjects with progressive mild cognitive impairment than in those with stable mild cognitive impairment subjects (p < 0.001). Meanwhile, CSF sPDGFRß was significantly associated with yearly changes in MMSE scores in the CDR 0.5 group (ß = - 0.400, p = 0.020) and CDR 0.5 (A+) subgroup (ß = - 0.542, p = 0.019). CONCLUSIONS: We provide evidence that increased CSF sPDGFRß is associated with BBB leakage in the early cognitive impairment stage of AD, which may contribute to cognitive impairment in AD progression.

[Corrigendum] LRIG2 promotes the proliferation and cell cycle progression of glioblastoma cells in vitro and in vivo through enhancing PDGFRß signaling.

Subsequently to the publication of the above article and a Corrigendum that addressed the issue of a misspelling of one of the authors' names (DOI: 10.3892/ijo.2019.4769; published online on April 2, 2019), the authors have subsequently discovered that Fig. 7 on p. 1079 contained a duplication in two of the panels that might cause the readers some confusion. The authors were able to re-examine the original data, repeat the experiment, and have decided to revise Fig. 7. The corrected version of Fig. 7, showing replacement data for the p-Akt and Cyclin D1 experiments, is shown on the next page. The authors confirm that these data continue to support the main conclusions presented in their paper, and are grateful to the Editor of International Journal of Oncology for allowing them this opportunity to publish a Corrigendum. They also apologize to the readership for any inconvenience caused. [the original article was published in International Journal of Oncology 10.3892/ijo.2018.4482].

[Successful treatment with imatinib for a patient with myeloid neoplasms with eosinophilia and abnormalities of PDGFRB due to t (5;14)(q33;q22)].

A 50-year old man with a 1-year history of eosinophilia presented with an eosinophil count exceeding 13,800/mm3 in the peripheral blood at the first visit. Bone marrow examination revealed that eosinophils accounted for 30% of the nucleated cell count, and G-band karyotyping analysis detected t (5;14)(q33;q22). Using peripheral blood FISH test, he was found to have platelet-derived growth factor receptor ß (PDGFRB) locus rearrangement at 5q32-33. The level of eosinophils in the peripheral blood reduced markedly 3 days after the initiation of Imatinib mesylate, 400 mg daily. This treatment was administered for 2 years, after which the peripheral blood FISH test was negative for PDGFRB. In this disease, although most cases are with t (5;12), those with t (5;14) are relatively rare, and the long-term course of this translocation is unknown.

True radial artery aneurysm in a patient with somatic mosaicism for a mutation in platelet-derived growth factor receptor ß gene.

We have presented the case of a right radial artery aneurysm (RAA) in a 27-year-old man with cerebral and coronary artery aneurysms and features of Parkes-Weber syndrome (port-wine stains and right upper extremity arteriovenous malformation and overgrowth). The RAA was repaired with an interposition great saphenous vein bypass graft. Analysis of the intracranial artery aneurysm and affected skin demonstrated a somatic mutation in the platelet-derived growth factor receptor-ß gene. Mosaicism was present in the RAA but not in the great saphenous vein. Somatic mosaicism should be considered as a possible etiology for peripheral aneurysms in patients for whom standard genetic test results are unrevealing.

New perspective into mesenchymal stem cells: Molecular mechanisms regulating osteosarcoma.

Mesenchymal stem cells (MSCs) are multipotent stem cells with significant potential for regenerative medicine. The tumorigenesis of osteosarcoma is an intricate system and MSCs act as an indispensable part of this, interacting with the tumor microenvironment (TME) during the process. MSCs link to cells by acting on each component in the TME via autocrine or paracrine extracellular vesicles for cellular communication. Because of their unique characteristics, MSCs can be modified and processed into good biological carriers, loaded with drugs, and transfected with anticancer genes for the targeted treatment of osteosarcoma. Previous high-quality reviews have described the biological characteristics of MSCs; this review will discuss the effects of MSCs on the components of the TME and cellular communication and the prospects for clinical applications of MSCs.

A small molecular multi-targeting tyrosine kinase inhibitor, anlotinib, inhibits pathological ocular neovascularization.

Ocular neovascularization is a devastating pathology observed in numerous ocular diseases and is a major cause of blindness. However, all current treatments have their limitations. Hence, it is important to explore new therapeutic strategies. This study aimed to investigate the role of anlotinib, a small molecular multi-targeting tyrosine kinase inhibitor, in ocular neovascularization. Anlotinib administration did not induce any cytotoxicity and tissue toxicity at the tested concentrations. Cellular functional experiments demonstrated that anlotinib inhibited the viability, proliferation, migration, and tube formation ability of endothelial cells (ECs) and pericytes. Western blot analysis demonstrated that anlotinib significantly inhibited the phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR2) and platelet-derived growth factor receptor ß (PDGFR-ß), as well as their downstream signaling pathways stimulated by VEGF or PDGF-BB, in a concentration-dependent manner in ECs and pericytes. Using an oxygen-induced retinopathy (OIR) model, our results demonstrated that injection of anlotinib reduced avascular areas and pathological neovascular tufts. Furthermore, using a laser-induced choroidal neovascularization (CNV) model, we observed that the combined treatment of anlotinib and Lucentis reduced the size and thickness of CNV lesions compared to Lucentis monotherapy alone. Taken together, our results suggest that anlotinib could be a promising drug candidate for ocular neovascularization.

Inhibition of platelet-derived growth factor receptor synergistically increases the pharmacological effect of tamoxifen in estrogen receptor α positive breast cancer.

The platelet-derived growth factor (PDGF) family, a complex and imperative group of proangiogenic factors, acts as strong cell growth chemokines and is essential for the progression of malignancy in humans. In the present study, it was observed that aberrant PDGFB expression is associated with survival rates in patients with estrogen receptor-positive (ER+) breast cancer unlike other subtypes, including PDGFA, PDGFC and PDGFD. Accordingly, the effect of specific PDGF receptor (PDGFR) inhibitors on ER-α+ breast cancer cells was investigated. To block the PDGF-BB signaling pathway, PDGFR inhibitors (sunitinib or ponatinib) were employed. Sunitinib and ponatinib were found to arrest the cell cycle at the G0-G1 phase. In addition, the two PDGFR inhibitors were revealed to significantly inhibit cell growth and decrease the expression of matrix metalloproteinase-1, which is one of the metastasis-related genes. Finally, the combined effects of the two PDGFR inhibitors with tamoxifen were investigated. The results demonstrated that the combination of two PDGFR inhibitors with tamoxifen inhibited the growth of cells more consistently, compared with the effect mediated by tamoxifen alone. Therefore, it is proposed that PDGFR inhibitors, including sunitinib and ponatinib, should be applied effectively to treat ER-α+ breast cancer.

Low-activity programming of the PDGFRß/FAK pathway mediates H-type vessel dysplasia and high susceptibility to osteoporosis in female offspring rats after prenatal dexamethasone exposure.

Dexamethasone is a common synthetic glucocorticoid drug that can promote foetal lung maturity. An increasing number of studies have shown that prenatal dexamethasone exposure (PDE) can cause a variety of short-term and long-term hazards to offspring, including bone development toxicity. H-type vessels are a newly discovered subtype of blood vessels associated with promoted bone formation and maintenance of bone mass. In this study, we aimed to explore whether H-type blood vessels are involved in PDE-induced long bone development toxicity in offspring and its mechanism. In vivo, we injected dexamethasone (0.2 mg/kg.d) subcutaneously at gestational days 9-20 and observed the H-type vessel abundance and bone mass at different time points in the offspring rats. In vitro, we investigated the effect of dexamethasone (0, 20, 100, and 500 nM) on the tube formation function of rat bone marrow-derived endothelial progenitor cells (EPCs) and explored its mechanism. Our results showed that the adult PDE female offspring rats were susceptible to osteoporosis. In addition, PDE inhibited bone mass, H-type vessel formation and the expression of bone platelet-derived growth factor receptor ß (PDGFRß)/focal adhesion kinase (FAK) pathway-related genes in antenatal and postnatal female offspring. Moreover, PDE promoted the expression of bone glucocorticoid receptor (GR), CCAAT and enhancer binding protein α (C/EBPα) and miR-34c in female foetuses. Dexamethasone suppressed the tube formation of rat bone marrow-derived EPCs and the activity of the PDGFRß/FAK pathway, which was mediated by GR/C/EBPα/miR-34c signalling activation. In summary, PDE can cause H-type vessel dysplasia and high susceptibility to osteoporosis in female offspring, and its mechanism is related to the low-activity programming of the PDGFRß/FAK pathway induced by GR/C/EBPα/miR-34c signalling activation. This study enhances the understanding of the molecular mechanism of dexamethasone-induced bone development toxicity and provides new insights for exploring the early intervention and therapeutic targets of foetal-derived osteoporosis.

A novel experimental approach to evaluate guided bone regeneration (GBR) in the rat femur using a 3D-printed CAD/CAM zirconia space-maintaining barrier.

INTRODUCTION: Obtaining a certain bone volume is an important goal in implantology or orthopedics. Thus, after tooth extraction, quite a lot of horizontal and vertical alveolar bone is lost in time and can be detrimental to the implant treatment outcome, while the treatment of critical bone defects is a considerable challenge for surgery. OBJECTIVES: In this study we designed a new in vivo model as an useful experimental tool to assess guided bone regeneration (GBR) using a computer-aided design/manufacturing (CAD-CAM) space-maintaining barrier. METHODS: The barrier was 3D printed with three progressive heights, surgically placed on rat femur, and GBR results were analyzed at 2, 4, and 8 weeks by X-ray and bone mineral density analysis, histology/morphometry and by immunofluorescence and immunohistochemistry for osteogenesis and angiogenesis evaluation. RESULTS: The obtained results show that the proposed experimental model provides a real-time useful information on progressive bone tissue formation, which depends on the volume of isolated space created for GBR and on molecular events that lead to satisfactory vertical and horizontal bone augmentation and osteointegration. CONCLUSION: In conclusion, the proposed customized three-dome space-maintaining barrier is suitable as an experimental tool to assess the potential of using the designed barriers in dentistry and orthopedics to promote the formation of new bone and determine their space- and time-dependent limitations. Meanwhile, guided bone augmentation for dentistry requires subsequent evaluation on an alveolar bone preclinical model followed by clinical implementation.

Activation of platelet-derived growth factor receptor ß in the severe fever with thrombocytopenia syndrome virus infection.

Severe fever with thrombocytopenia syndrome (SFTS), an emerging viral infectious disease with a high case fatality rate, is caused by the SFTS virus (SFTSV). Although several cellular molecules involved in viral entry have been identified, the entry mechanisms of SFTSV remain unclear. In this study, we screened the protein kinase inhibitors in inhibitory effects on the infection of Vero cells with SFTSV using InhibitorSelect™ Protein Kinase Library Series (Merck & Co., Inc., Kenilworth, NJ, USA). Several types of inhibitors targeted to platelet-derived growth factor receptor ß (PDGFRß) inhibited the infection of Vero, Huh7, and NIH3T3 cells with SFTSV in a dose-dependent manner within the noncytotoxic range. In addition, these protein kinase inhibitors also inhibited the infection of the target cells with SFTSV glycoprotein (SFTSV-GP) pseudotyped virus (SFTSVpv). Activation of PDGFRß phosphorylation was detected in SFTSV-treated cells. The infectivities of SFTSVpv were specifically decreased not only in NIH3T3 cells treated with siRNA for PDGFRß but also in NIH3T3 cells treated with anti-PDGFRß neutralizing antibody in a dose-dependent manner. SFTSV growth and entry of SFTSVpv were also inhibited by Akt inhibitors. Activation of Akt phosphorylation was also detected in SFTSV-treated cells. These data indicate that PDGFRß is one of the important host factors in the entry steps of SFTSV.

The Interaction Between Spinal PDGFRß and µ Opioid Receptor in the Activation of Microglia in Morphine-Tolerant Rats.

PURPOSE: Opioid tolerance remains a challenging problem, which limits prolonged drug usage in clinics. Previous studies have shown a fundamental role of platelet-derived growth factor receptor ß submit (PDGFRß) in morphine tolerance. The aim of this study was to investigate the mechanisms of spinal PDGFRß activation in morphine tolerance. METHODS: Rats were treated with morphine for 7 days and the effect of drug was evaluated by tail-flick latency test. By using Western blot and real-time PCR, the interaction between µ opioid receptor (MOR) and PDGFRß in microglia activation, as well as related signaling pathways during morphine tolerance were investigated. RESULTS: Chronic PDGFRß agonist could induce microglia activation in spinal cord and decrease the analgesic effect of morphine. PDGFRß inhibitor suppressed microglia activation during the development of morphine tolerance. Furthermore, antagonizing MOR could effectively inhibit the phosphorylations of PDGFRß and JNK. Blocking PDGFRß had no influence on JNK signaling, while JNK inhibitor could decrease the phosphorylation of PDGFRß. CONCLUSION: These results provide direct evidence that repeatedly activating MOR by morphine could induce the transactivation of PDGFRß via JNK MAPK in spinal cord, which leads to microglia activation during the development of morphine tolerance.

Long Noncoding RNA TYKRIL Plays a Role in Pulmonary Hypertension via the p53-mediated Regulation of PDGFRß.

Rationale: Long noncoding RNAs (lncRNAs) are emerging as important regulators of diverse biological functions. Their role in pulmonary arterial hypertension (PAH) remains to be explored.Objectives: To elucidate the role of TYKRIL (tyrosine kinase receptor-inducing lncRNA) as a regulator of p53/ PDGFRß (platelet-derived growth factor receptor ß) signaling pathway and to investigate its role in PAH.Methods: Pericytes and pulmonary arterial smooth muscle cells exposed to hypoxia and derived from patients with idiopathic PAH were analyzed with RNA sequencing. TYKRIL knockdown was performed in above-mentioned human primary cells and in precision-cut lung slices derived from patients with PAH.Measurements and Main Results: Using RNA sequencing data, TYKRIL was identified to be consistently upregulated in pericytes and pulmonary arterial smooth muscles cells exposed to hypoxia and derived from patients with idiopathic PAH. TYKRIL knockdown reversed the proproliferative (n = 3) and antiapoptotic (n = 3) phenotype induced under hypoxic and idiopathic PAH conditions. Owing to the poor species conservation of TYKRIL, ex vivo studies were performed in precision-cut lung slices from patients with PAH. Knockdown of TYKRIL in precision-cut lung slices decreased the vascular remodeling (n = 5). The number of proliferating cell nuclear antigen-positive cells in the vessels was decreased and the number of terminal deoxynucleotide transferase-mediated dUTP nick end label-positive cells in the vessels was increased in the LNA (locked nucleic acid)-treated group compared with control. Expression of PDGFRß, a key player in PAH, was found to strongly correlate with TYKRIL expression in the patient samples (n = 12), and TYKRIL knockdown decreased PDGFRß expression (n = 3). From the transcription factor-screening array, it was observed that TYKRIL knockdown increased the p53 activity, a known repressor of PDGFRß. RNA immunoprecipitation using various p53 mutants demonstrated that TYKRIL binds to the N-terminal of p53 (an important region for p300 interaction with p53). The proximity ligation assay revealed that TYKRIL interferes with the p53-p300 interaction (n = 3) and regulates p53 nuclear translocation.Conclusions: TYKRIL plays an important role in PAH by regulating the p53/PDGFRß axis.

Gint4.T-Modified DNA Tetrahedrons Loaded with Doxorubicin Inhibits Glioma Cell Proliferation by Targeting PDGFRß.

Glioma is one of the deadliest intrinsic brain tumours due to its invasive growth. The effect of glioma treatment is poor because of the presence of the blood-brain barrier and blood tumour barrier and insufficient drug targeting. DNA tetrahedrons (TDN) show great potential for drug delivery and may be a novel therapeutic strategy for glioma. In this study, we used TDN to deliver doxorubicin (DOX) for the glioma therapy. Gint4.T, an aptamer that could recognize platelet-derived growth factor receptor ß on tumour cell, was used to modify TDN (Apt-TDN) for targeted drug delivery. The TDN were self-assembled by one-step synthesis, which showed small size (10 nm) and negative charge. Fetal bovine serum test showed its stability as a drug delivery vehicle. Apt-TDN could be effectively taken up by U87MG cells. Compared with DOX and DOX@TDN (TDN loaded with DOX), the DOX@Apt-TDN (Gint4.T-modified TDN loaded with DOX) showed more early apoptosis rate, higher cell cycle arrest, and greater cytotoxicity towards U87MG cells. In conclusion, our findings indicated that DOX@Apt-TDN provides a novel therapy with promising clinical application for gliomas patients.

Plau/Plaur double-deficiency did not worsen lesion severity or vascular integrity after traumatic brain injury.

Binding of urokinase-type plasminogen activator receptor (uPAR) to its ligand uPA or to its plasma membrane partner, platelet-derived growth factor receptor ß (PDGFRß), promotes neuroprotection, cell proliferation, and angiogenesis. Following injury, single deficiency in uPA or uPAR leads in increased tissue loss and compromised vascular remodeling. We hypothesized that double-deficiency of uPAR (Plaur) and uPA (Plau) would result in increased lesion area and poor vascular integrity after traumatic brain injury (TBI). TBI was induced by lateral fluid-percussion injury in Plau/Plaur double-knockout (dKO) and wild-type (Wt) mice. The cortical lesion area was quantified in unfolded cortical maps prepared from thionin-stained sections at 4 d or 30 d post-TBI. The density of PDGFRß+ pericytes and blood vessels was calculated from immunostained sections. Blood-brain barrier leakage was analyzed using ImageJ® from IgG-immunostained sections. Genotype had no effect on the total area of the cortical lesion at 4 d or 30 d post-TBI (p > 0.05) or its progression as the overall lesion area was comparable at 4 d and 30 d post-TBI in both genotypes (p > 0.05). Subfield analysis, however, indicated that damage to the visual cortex at 4 d post-TBI in dKO-TBI mice was 53 % of that in Wt-TBI mice (p < 0.05). Both genotypes had a higher density of PDGFRß-positive pericytes at 4 d than at 30 d post-TBI (p < 0.05), but no genotype effect was detected between these time-points (p > 0.05). TBI-induced increase in the density of PDGFRß+ blood vessels at the region adjacent to the lesion core was comparable in both genotypes (p > 0.05). Genotype had no effect on TBI-induced IgG leakage into the perilesional cortical parenchyma (p > 0.05). Contrary to our expectations, Plau/Plaur double-deficiency did not aggravate TBI-related structural outcome.

The Interaction of EphA4 With PDGFRß Regulates Proliferation and Neuronal Differentiation of Neural Progenitor Cells in vitro and Promotes Neurogenesis in vivo.

Neural progenitor cells (NPCs) have great potentials in cell replacement therapy for neurodegenerative diseases, such as Alzheimer's disease (AD), by promoting neurogenesis associated with hippocampal memory improvement. Ephrin receptors and angiogenic growth factor receptors have a marked impact on the proliferation and differentiation of NPCs. Although ephrin receptor A4 (EphA4) was shown to directly interact with platelet-derived growth factor receptor ß (PDGFRß), the functional effects of this interaction on neurogenesis in cultured NPCs and adult hippocampus have not yet been studied. Immunoprecipitation demonstrated that EphA4 directly interacted with PDGFRß in NPCs under ligand stimulation. Ephrin-A1 and PDGF-platelet-derived growth factor BB (BB) significantly increased proliferation and neuronal differentiation of NPCs, which was further augmented by combined treatment of Ephrin-A1 and PDGF-BB. We also found that ligand-dependent proliferation and neuronal differentiation were inhibited by the dominant-negative EphA4 mutant or a PDGFR inhibitor. Most importantly, injection of ephrin-A1 and/or PDGF-BB promoted hippocampal NPC proliferation in the APP/PS1 mouse model of AD, indicating that direct interaction of EphA4 with PDGFRß plays a functional role on neurogenesis in vivo. Finally, studies in NPCs showed that the EphA4/PDGFRß/FGFR1/FRS2α complex formed by ligand stimulation is involved in neurogenesis via ERK signaling. The present findings provided a novel insight into the functional role of direct interaction of EphA4 and PDGFRß in neurogenesis, implicating its potential use for treating neurodegenerative diseases.

Pericyte-Mediated Tissue Repair through PDGFRß Promotes Peri-Infarct Astrogliosis, Oligodendrogenesis, and Functional Recovery after Acute Ischemic Stroke.

Post-stroke functional recovery can occur spontaneously during the subacute phase; however, how post-stroke fibrotic repair affects functional recovery is highly debated. Platelet-derived growth factor receptor ß (PDGFRß)-expressing pericytes are responsible for post-stroke fibrotic repair within infarct areas; therefore, we examined peri-infarct neural reorganization and functional recovery after permanent middle cerebral artery occlusion (pMCAO) using pericyte-deficient Pdgfrb+/- mice. Time-dependent reduction of infarct area sizes, i.e., repair, was significantly impaired in Pdgfrb+/- mice with recovery of cerebral blood flow (CBF) in ischemic areas attenuated by defective leptomeningeal arteriogenesis and intrainfarct angiogenesis. Peri-infarct astrogliosis, accompanied by increased STAT3 phosphorylation, was attenuated in Pdgfrb+/- mice. Pericyte-conditioned medium (PCM), particularly when treated with platelet-derived growth factor subunit B (PDGFB) homodimer (PDGF-BB; PCM/PDGF-BB), activated STAT3 and enhanced the proliferation and activity of cultured astrocytes. Although peri-infarct proliferation of oligodendrocyte (OL) precursor cells (OPCs) was induced promptly after pMCAO regardless of intrainfarct repair, OPC differentiation and remyelination were significantly attenuated in Pdgfrb+/- mice. Consistently, astrocyte-CM (ACM) promoted OPC differentiation and myelination, which were enhanced remarkably by adding PCM/PDGF-BB to the medium. Post-stroke functional recovery correlated well with the extent and process of intrainfarct repair and peri-infarct oligodendrogenesis. Overall, pericyte-mediated intrainfarct fibrotic repair through PDGFRß may promote functional recovery through enhancement of peri-infarct oligodendrogenesis as well as astrogliosis after acute ischemic stroke.