PDGFRB Research Articles

The antihypertensive agent hydralazine reduced extracellular matrix synthesis and liver fibrosis in nonalcoholic steatohepatitis exacerbated by hypertension.

Hypertension is an important risk factor for nonalcoholic steatohepatitis. We have previously demonstrated that hypertensive rats fed a high fat and cholesterol (HFC) diet incurred a more severe hepatic inflammatory response and fibrosis. Here we investigated the role of hypertension in NASH by comparing HFC-induced hepatic fibrogenesis between spontaneously hypertensive rats (SHRs) and their normotensive Wistar Kyoto counterpart. Compared to the counterpart, the HFC diet led to stronger aggregation of CD68-positive macrophages in SHRs. HFC feeding also resulted in significantly higher upregulation of the fibrosis-related gene alpha-smooth muscle actin in SHR. The HFC diet induced higher overexpression of serum tissue inhibitor of metalloproteinase-1 (TIMP1) and greater suppression of matrix metalloproteinase-2 (MMP2):TIMP1, MMP8:TIMP1, and MMP9:TIMP1 ratios, as a proxy of the activities of these MMPs in SHR. Administration of the antihypertensive agent hydralazine to SHRs significantly ameliorated HFC-induced liver fibrosis; it suppressed the aggregation of CD68-positive macrophages and the upregulation of platelet-derived growth factor receptor beta, and collagen, type 1, alpha-1 chain. In conclusion, a hypertensive environment exacerbated the hepatic fibrogenetic effects of the HFC diet; while the effects were partially reversed by the antihypertensive agent hydralazine. Our data suggest that antihypertensive drugs hold promise for treating NASH exacerbated by hypertension.

Retinal capillary degeneration and blood-retinal barrier disruption in murine models of Alzheimer\u2019s disease

Extensive effort has been made studying retinal pathology in Alzheimer’s disease (AD) to improve early noninvasive diagnosis and treatment. Particularly relevant are vascular changes, which appear prominent in early brain pathogenesis and could predict cognitive decline. Recently, we identified platelet-derived growth factor receptor beta (PDGFRβ) deficiency and pericyte loss associated with vascular Aβ deposition in the neurosensory retina of mild cognitively impaired (MCI) and AD patients. However, the pathological mechanisms of retinal vascular changes and their possible relationships with vascular amyloidosis, pericyte loss, and blood-retinal barrier (BRB) integrity remain unknown. Here, we evaluated the retinas of transgenic APPSWE/PS1ΔE9 mouse models of AD (ADtg mice) and wild-type mice at different ages for capillary degeneration, PDGFRβ expression, vascular amyloidosis, permeability and inner BRB tight-junction molecules. Using a retinal vascular isolation technique followed by periodic acid-Schiff or immunofluorescent staining, we discovered significant retinal capillary degeneration in ADtg mice compared to age- and sex-matched wild-type mice (P < 0.0001). This small vessel degeneration reached significance in 8-month-old mice (P = 0.0035), with males more susceptible than females. Degeneration of retinal capillaries also progressively increased with age in healthy mice (P = 0.0145); however, the phenomenon was significantly worse during AD-like progression (P = 0.0001). A substantial vascular PDGFRβ deficiency (~ 50% reduction, P = 0.0017) along with prominent vascular Aβ deposition was further detected in the retina of ADtg mice, which inversely correlated with the extent of degenerated capillaries (Pearson’s r = − 0.8, P = 0.0016). Importantly, tight-junction alterations such as claudin-1 downregulation and increased BRB permeability, demonstrated in vivo by retinal fluorescein imaging and ex vivo following injection of FITC-dextran (2000 kD) and Texas Red-dextran (3 kD), were found in ADtg mice. Overall, the identification of age- and Alzheimer’s-dependent retinal capillary degeneration and compromised BRB integrity starting at early disease stages in ADtg mice could contribute to the development of novel targets for AD diagnosis and therapy.

Galangin Inhibits LPS-Induced MMP-9 Expression via Suppressing Protein Kinase-Dependent AP-1 and FoxO1 Activation in Rat Brain Astrocytes.

PurposeNeuroinflammation, characterized by the increased expression of inflammatory proteins such as matrix metalloproteinases (MMPs), plays a critical role in neurodegenerative disorders. Lipopolysaccharide (LPS) has been shown to upregulate MMP-9 expression through the activation of various transcription factors, including activator protein 1 (AP-1) and forkhead box protein O1 (FoxO1). The flavonoid 3,5,7-trihydroxy-2-phenyl-4H-1-benzopyran-4-one (galangin) has been demonstrated to possess antioxidant and anti-inflammatory properties in various types of cells. Here, we investigated the mechanisms underlying the inhibitory effect of galangin on LPS-induced MMP-9 expression in rat brain astrocytes (RBA-1 cells).MethodsPharmacological inhibitors and siRNAs were employed to explore the effects of galangin on LPS-challenged RBA-1 cells. Gelatin zymography, Western blotting, real-time PCR, and a luciferase reporter assay were used to detect MMP-9 activity, protein expression, mRNA levels, and promoter activity, respectively. The protein kinases involved in the LPS-induced MMP-9 expression were determined by Western blot. A chromatin immunoprecipitation (ChIP) assay was employed to evaluate the activity of c-Jun at the MMP-9 promoter.ResultsGalangin treatment attenuated the LPS-mediated induction of MMP-9 protein and mRNA expression, as well as the activity at the MMP-9 promoter. In addition, galangin exerted its inhibitory effects on MMP-9 expression through suppressing the LPS-stimulated activation of proline-rich tyrosine kinase (Pyk2), platelet-derived growth factor receptor beta (PDGFRβ), phosphoinositide 3-kinase (PI3K), protein kinase B (Akt), mammalian target of rapamycin (mTOR), and mitogen-activated protein kinases (MAPKs). Pretreatment with galangin attenuated the LPS-induced phosphorylation of c-Jun and FoxO1. LPS-induced cell migration was also suppressed by galangin pretreatment.ConclusionGalangin attenuates the LPS-induced inflammatory responses, including the induction of MMP-9 expression and cell migration, via inhibiting Pyk2/PDGFRβ/PI3K/Akt/mTOR/JNK1/JNK2 and p44/p42 MAPK cascade-dependent AP-1 and FoxO1 activities. These results provide new insights into the mechanisms through which galangin mitigates LPS-induced inflammatory responses, and suggest novel strategies for the management of LPS-related brain diseases.

Lipopolysaccharide Reverses Hepatic Stellate Cell Activation Through Modulation of cMyb, Small Mothers Against Decapentaplegic, and CCAAT/Enhancer-Binding Protein C/EBP Transcription Factors.

During liver injury, quiescent hepatic stellate cells (qHSCs) transdifferentiate into proliferative and fibrogenic activated myofibroblastic phenotype (activated hepatic stellate cell; aHSCs) expressing smooth muscle α-actin (αSMA) and platelet-derived growth factor beta receptor (PDGFβR). Their interactions with gut-derived bacterial lipopolysaccharide (LPS) are implicated in hepatic fibrogenesis. However, LPS can also attenuate fibrogenic characteristics of aHSCs. We examined molecular mechanisms of antifibrogenic effects of LPS on aHSCs in vitro and in vivo. Culture-activated rat HSCs were exposed to 0-100ng/mL of LPS or its active component, diphosphoryl-lipid A (DPLA), and parameters of fibrosis and inflammatory cytokines/chemokines were determined by qRT-PCR, western, and immunohistochemical analyses. In vivo, HSCs were activated by repeated CCl4 administration to rats every 3days for 3 or 8weeks, then challenged with LPS (5mg/kg; IP). HSCs were isolated 24hours later, and fibrogenic/inflammatory parameters were analyzed. LPS induced phenotypic changes in aHSCs (rounding, size reduction) and loss of proliferation. LPS down-regulated expression of αSMA, PDGFβR, transforming growth factor beta receptor 1 (TGFβR1), collagen 1α1 (Col1α1), and fibronectin while up-regulating tumor necrosis factor alpha, interleukin-6, and C-X-C motif chemokine ligand 1 expression. LPS did not increase peroxisome proliferation-activated receptor gamma expression or lipid accumulation typical of qHSCs. DPLA elicited the same effects as LPS on aHSCs, indicating specificity, and monophosphoryl lipid A down-regulated fibrogenic markers, but elicited very weak inflammatory response. LPS down-regulated the expression of cMyb, a transcription factor for αSMA, and up-regulated small mother against decapentaplegic (SMAD)7 and CCAAT/enhancer-binding protein (C/EBP)δ, the transcriptional inhibitors of Col1α1 expression. In vivo LPS treatment of aHSCs inhibited their proliferation, down-regulated PDGFβR, αSMA, TGFβR1, Col1α1, and cMyb expression, and increased expression of SMAD7, C/EBPα, and C/EBPδ. In conclusion, LPS induces a unique phenotype in aHSCs associated with down-regulation of key fibrogenic mechanisms and thus may have an important role in limiting fibrosis.

A nuclear fluorescent dye identifies pericytes at the neurovascular unit.

Perivascular pericytes are key regulators of the blood-brain barrier, vascular development, and cerebral blood flow. Deciphering pericyte roles in health and disease requires cellular tracking; yet, pericyte identification remains challenging. A previous study reported that the far-red fluorophore TO-PRO-3 (642/661), usually employed as a nuclear dye in fixed tissue, was selectively captured by live pericytes from the subventricular zone. Herein, we validated TO-PRO-3 as a specific pericyte tracer in the nervous system (NS). Living pericytes from ex vivo murine hippocampus, cortex, spinal cord, and retina robustly incorporated TO-PRO-3. Classical pericyte immunomarkers such as chondroitin sulphate proteoglycan neuron-glial antigen 2 (NG2) and platelet-derived growth factor receptor beta antigen (PDGFrβ) and the new pericyte dye NeuroTrace 500/525 confirmed cellular specificity of dye uptake. The TO-PRO-3 signal enabled quantification of pericytes density and morphometry; likewise, TO-PRO-3 labeling allowed visualization of pericytes associated with other components of the neurovascular unit. A subset of TO-PRO-3 stained cells expressed the contractile protein α-SMA, indicative of their ability to control the capillary diameter. Uptake of TO-PRO-3 was independent of connexin/pannexin channels but was highly sensitive to temperature and showed saturation, suggesting that a yet unidentified protein-mediated active transport sustained dye incorporation. We conclude that TO-PRO-3 labeling provides a reliable and simple tool for the bioimaging of pericytes in the murine NS microvasculature.

The epigenetic treatment remodel genome-wide histone H4 hyper-acetylation patterns and affect signaling pathways in acute promyelocytic leukemia cells

Although majority of acute promyelocytic leukemia (APL) patients achieve complete remission after the standard treatment, 5–10% of patients are shown to relapse or develop resistance to treatment. In such cases, medications that target epigenetic processes could become an appealing supplementary approach. In this study, we tested the anti-leukemic activity of histone deacetylase inhibitor Belinostat (PXD101) and histone methyltransferase inhibitor 3-Deazaneplanocin A combined with all-trans retinoic acid in APL cells NB4, promyelocytes resembling HL-60 cells and APL patients' cells. After HL-60 and NB4 cell treatment, ChIP-sequencing was performed using antibodies against hyper-acetylated histone H4. Hyper-acetylated histone H4 distribution peaks were compared in treated vs untreated HL-60 and NB4 cells. Results demonstrated that in treated HL-60 cells, the majority of peaks were distributed within the regions of proximal promoters, whereas in treated NB4 cells, hyper-acetylated histone H4 peaks were mainly localized in gene body regions. Further ChIP-seq data analysis revealed the changes in histone H4 hyper-acetylation in promoter/gene body regions of genes involved in cancer signaling pathways. In addition, quantitative gene expression analysis proved changes in various cellular pathways important for carcinogenesis. Epigenetic treatment down-regulated the expression of MTOR, LAMTOR1, WNT2B, VEGFR3, FGF2, FGFR1, TGFA, TGFB1, TGFBR1, PDGFA, PDGFRA and PDGFRB genes in NB4, HL-60 and APL patients’ cells. In addition, effect of epigenetic treatment on protein expression of aforementioned signaling pathways was confirmed with mass spectrometry analysis. Taken together, these results provide supplementary insights into molecular changes that occur during epigenetic therapy application in in vitro promyelocytic leukemia cell model.

PDGFRB as a potential therapeutic target of ankylosing spondylitis: validation following bioinformatics analysis

Ankylosing spondylitis (AS) is a chronic, progressive, and inflammatory disease that mainly affects the central axis joint. Although this disease has already been well documented and studied, its pathogenesis is still not well understood. This study aimed to screen and identify key candidate genes involved in the progression of AS. For this purpose, expression profiles of GSE39340 and GSE41038 were downloaded from the Gene Expression Omnibus and displayed in the form of volcano plots and heatmaps. Differentially expressed genes (DEGs) were identified by the Limma package in R and functional enrichment analyses were performed. Moreover, STRING and Cytoscape were utilized to construct protein-protein interaction (PPI) networks and screen significant modules. Immunohistochemistry (IHC) in tissue chips of AS and normal human synovial tissues was performed to confirm the major proteins associated with its development. Western blotting (WB) and alizarin red staining were applied to validate the expression level of platelet-derived growth factor receptor beta (PDGFRB) and function during osteogenesis differentiation of fibroblasts in AS. A total of 256 DEGs were screened, including 191 up-regulated genes and 65 down-regulated genes. The enriched functions of these identified genes mainly included adherens junction, focal adhesion, and cell-substrate adherens junction. The pathways most highly associated with the progression of AS were TGF-β signaling pathway, the Hippo signaling pathway, and the AGE-RAGE signaling pathway. In addition, IHC showed that mitogen-activated protein kinase 1 (MAPK1), C-X-C motif chemokine receptor 4 (CXCR4), and PDGFRB were highly expressed in AS. PDGFRB was found upregulated during osteogenesis of fibroblasts and stimulates osteogenesis in AS. These findings may improve our understanding of the molecular mechanisms controlling AS. Pharmacological targeting of PDGFRB may initiate a possible suppression of bone formation in AS.

Acute Traumatic Brain Injury-Induced Neuroinflammatory Response and Neurovascular Disorders in the Brain.

Acute traumatic brain injury (TBI) leads to neuroinflammation, neurodegeneration, cognitive decline, psychological disorders, increased blood-brain barrier (BBB) permeability, and microvascular damage in the brain. Inflammatory mediators secreted from activated glial cells, neurons, and mast cells are implicated in the pathogenesis of TBI through secondary brain damage. Abnormalities or damage to the neurovascular unit is the indication of secondary injuries in the brain after TBI. However, the precise mechanisms of molecular and ultrastructural neurovascular alterations involved in the pathogenesis of acute TBI are not yet clearly understood. Moreover, currently, there are no precision-targeted effective treatment options to prevent the sequelae of TBI. In this study, mice were subjected to closed head weight-drop-induced acute TBI and evaluated neuroinflammatory and neurovascular alterations in the brain by immunofluorescence staining or quantitation by enzyme-linked immunosorbent assay (ELISA) procedure. Mast cell stabilizer drug cromolyn was administered to inhibit the neuroinflammatory response of TBI. Results indicate decreased level of pericyte marker platelet-derived growth factor receptor-beta (PDGFR-β) and BBB-associated tight junction proteins junctional adhesion molecule-A (JAM-A) and zonula occludens-1 (ZO-1) in the brains 7 days after weight-drop-induced acute TBI as compared with the brains from sham control mice indicating acute TBI-associated BBB/tight junction protein disruption. Further, the administration of cromolyn drug significantly inhibited acute TBI-associated decrease of PDGFR-β, JAM-A, and ZO-1 in the brain. These findings suggest that acute TBI causes BBB/tight junction damage and that cromolyn administration could protect this acute TBI-induced brain damage as well as its long-time consequences.

A report of an unusual case of pediatric eosinophilia associated with platelet-derived growth factor receptor-beta rearrangement

AbstractEosinophilia is a common finding in the pediatric age group. While the majority of mild eosinophilia cases are benign and due to reactive causes, persistent hypereosinophilia is uncommon and requires prompt clinical evaluation because of the potential risk of end-organ damage associated with it. Given the broad differential diagnoses of eosinophilia, it is essential to have a systematic approach to the evaluation of unexplained eosinophilia in children. Here, we discuss the case of a 2-year-old child who presented with very high eosinophil counts. A systematic workup of the case helped us in arriving at a rare diagnosis of platelet-derived growth factor receptor-beta (PDGFRB)-rearranged clonal eosinophilia. Identification of such an entity is important as it has therapeutic implications, and early recognition helps in preventing associated end-organ damage by instituting appropriate therapy. Such cases of eosinophilia associated with platelet-derived growth factor receptor-alpha and PDGFRB rearrangement respond dramatically to imatinib.

Diagnosis of adult Philadelphia chromosome-like acute lymphoblastic leukemia by fluorescence in situ hybridization

目的建立应用荧光原位杂交技术（FISH）筛查成人Ph样急性淋巴细胞白血病（ALL）的体系。方法根据Ph样ALL的遗传学特征，设计了针对ABL1、ABL2、JAK2、EPOR、CRLF2、CSF1R、PDGFRB、P2RY8等基因断裂重排的FISH探针；对BCR-ABL1、ETV6-RUNX1、MLL基因断裂重排和E2A断裂重排均阴性的B-ALL，采用FISH进行Ph样ALL筛查，并结合流式免疫表型、靶向二代测序突变检测和RNA测序进行Ph样ALL诊断分析。结果2016年1月至2019年4月，南方医院血液科收治189例成人B-ALL，经FISH和（或）PCR检测，BCR-ABL1、ETV6-RUNX1、MLL断裂重排或E2A断裂重排阳性者共83例；其余106例患者接受Ph样ALL FISH探针筛查，其中，12例（11.3％）检出典型的Ph样ALL特异基因断裂重排，2例检出基因缺失。经RNA测序进一步验证，FISH检测Ph样ALL基因断裂重排结果灵敏度为71.4％，特异度为95.8％。综合免疫表型、靶向二代测序突变检测和RNA测序，共诊断融合基因阳性Ph样ALL 14例（13.2％）。结论FISH技术检测Ph样ALL具有较高的特异性，结合免疫表型和测序技术可完善诊断体系。

Abstract 4000: PDGFR is a key factor to regulate stemness and epithelial mesenchymal transition of colorectal cancer with suppression of tumor microenvironment

Abstract Background: The tumor microenvironment (TME) including stromal cells and immune cells is considered to be a crucial factor in clinical field. TME support cancer cells and contributes to tumor stemness and heterogeneity that cause treatment resistance. Platelet-derived growth factor (PDGF) is a well-known growth factor and it was reported to be involved in cancer growth and migration through PDGF receptors (PDGFRs). PDGFRs are cell surface type III tyrosine kinase receptors and two subtypes are known as PDGFRA and PDGFRB. We previously reported that the high PDGFR beta (PDGFRB) expression was an independent predictor of recurrence of colorectal cancer (CRC), and the inhibition of PDGFRB by PDGFR inhibitor, crenolanib, suppressed tumor growth and migration of CRC in vitro. However, PDGFRB is expressed not only in cancer cells but also in surrounding stromal cells that consist TME. In this study we revealed the interaction between cancer cells and tumor stromal cells via PDGFR, and examined the effectiveness of PDGFR inhibition in CRC treatment. Results: The effects of PDGFR inhibition were examined in four CRC cell lines (RKO, HCT116, HT29, and DLD1) and six primary cultured CRC cells (724iCC, 821iCC, 25DiCC, 603iCC, 602iCC, 622iCC, and 1M29FiCC) using crenolanib. Primary cultured CRC cells named 2D organoid (2DO) were established from surgically resected specimen according to the method we previously reported (AACR Annual Meeting 2018, 2019. BBRC, 2019). In CRC cells, crenolanib showed additive and synergistic effects with other anticancer drugs, and suppressed expression of stem cell markers including octamer-binding transcription factor 4 (Oct4). Exposure to cancer exosomes increased PDGFRB expression of fibroblasts and promoted transforming growth factor β (TGF-β) secretion, and they were suppressed by crenolanib. Co-culture with fibroblasts enhanced the expression of PDGFRB in cancer cells and promoted stemness and epithelial-mesenchymal transition (EMT) via TGFB signaling, which were suppressed by crenolanib. Among stem cell markers, we focused on Oct4. We previously reported that Oct4 promoted distant metastasis of CRC. Oct4 expression was significantly higher in 2DOs compared with cell lines. Oct4+ cells of 2DO were resistant to treatment and a single Oct4+ cell reproduced tumor heterogeneity. Oct4+ cells were supported by TGF-β, and suppressed by crenolanib. Oct4 expression was correlated with PDGFRB expression in clinical specimen, and patients with high expression of both PDGFRB and Oct4 had a worse prognosis than patients with either or both. Conclusions: PDGFR inhibition by crenolanib regulates stemness and of EMT in CRC via suppression of TGF-β signaling of tumor and TME. RDGFR could be a new therapeutic target to supress EMT and stem cells of CRC. Citation Format: Shiki Fujino, Norikatsu Miyoshi, Aya Ito, Masaru Sasaki, Takasyuki Ogino, Hidekazu Takahashi, Mamoru Uemura, Chu Matsuda, Tsunekazu Mizushima, Yuichiro Doki. PDGFR is a key factor to regulate stemness and epithelial mesenchymal transition of colorectal cancer with suppression of tumor microenvironment [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4000.

Abstract 3027: Application of machine learning and grid search approaches to minimize lucitanib pharmacokinetic variability following different dosing regimens

Abstract Background: Lucitanib is a potent tyrosine kinase inhibitor that selectively inhibits vascular endothelial growth factor receptors 1, 2, and 3 (VEGFR1-3), platelet-derived growth factor receptors alpha and beta (PDGFRα/β), and fibroblast growth factor receptors types 1, 2, and 3 (FGFR1-3). Lucitanib is being evaluated in patients with solid tumors in combination with other anticancer agents. The pharmacokinetics (PK) of lucitanib were described by a 2-compartment population PK model with first-order absorption and elimination. Body weight was a covariate on clearance and volume of distribution. Objective: We sought to compare the variability of lucitanib PK between body weight-based and fixed-dose regimens to inform dosing regimen selection. Methods: Lucitanib PK were simulated for 5000 virtual patients with a uniform distribution of body weight (40-120 kg). Patients either received a fixed dose (10 mg once daily) or a body weight-based dose. Genetic and grid search algorithms were used to identify the body weight-based dosing regimens that resulted in the smallest fraction of outliers, defined as subjects outside of the 5th and 95th prediction interval of the area under the curve during the dosing interval (tau) at steady state (AUCtau,ss) for 70-kg patients receiving the fixed dose. The genetic algorithm used a continuous body weight and dose search space, whereas the grid search algorithm limited the search space to discrete values of body weight and dose (ie, 5 kg increments for body weight and 0.25 mg increments for dose). The penalty function in both algorithms was the fraction of outliers. The optimized body weight-based regimens were compared to the fixed-dose regimen to evaluate lucitanib PK variability. Results: The genetic and grid search algorithms identified similar and reasonable dosing regimens. Two or 3 body weight-based dosing regimens decreased the fraction of outliers by 1%-4% in the overall population (40-120 kg) versus the fixed dose. However, within the low body weight group (40-50 kg), body weight-based dosing regimens substantially decreased the fraction of outliers, with exposure greater than the 95th percentile reduced by 10%-15% compared with the fixed dose. On the other hand, the fixed-dose regimen predicted fewer outliers with exposure below the 5th percentile versus the body weight-based dosing regimens. Conclusions: The genetic algorithm provided similar results to the more computationally demanding method of grid searching. Compared with a fixed-dose regimen, body weight-based regimens showed a small reduction in PK variability for lucitanib in the overall population, suggesting that there is limited benefit with body weight-based dosing. Dose optimization will be further evaluated with a growing understanding of the target therapeutic range and exposure-response relationships. Citation Format: Michelle Liao, Jessie Zhou, Mark Sale, Jim J. Xiao. Application of machine learning and grid search approaches to minimize lucitanib pharmacokinetic variability following different dosing regimens [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3027.

Abstract 3138: Colorectal cancer is associated with elevated plasma levels of soluble platelet-derived growth factor-dd (PDGF-DD) compared to plasma levels of benign colon disease patients

Abstract Introduction: Platelet-derived growth factor-DD (PDGF-DD), a member of the PDGF family, is secreted as a latent homodimer which is activated by uPA (urokinase). After binding to its receptor, PDGF Rβ, PDGF-DD plays a role in mesenchymal transition, cancer cell growth, migration, and invasion all of which are supported by the PDGF DD induced proangiogenic proteins MMP2, MMP9 and VEGF. Downregulation of PDGF DD suppresses both the expression of VEGF and MMP9 via Notch-1, NF-kappaB and VEGF directed neo-angiogenesis. Upregulated expression of PDGF DD has been noted in colon and many other cancers. This study's purpose was to compare preoperative (PreOp) plasma PDGF DD levels in colorectal cancer (CRC) and benign colon disease (BCD) patients (pts). Method: Pts undergoing colorectal resection for CRC or benign problems that had been prospectively enrolled in an IRB approved tissue and data bank for whom adequate Preop plasma samples were available were studied. Clinical, demographic, operative, and pathologic data were collected. The PDGF-DD levels in the preoperative plasma samples were determined via ELISA in duplicate and reported as median ±95% CI (pg/ml). The receiver operating characteristic (ROC) curve and area under the ROC curve (AUC) were used to evaluate the CRC diagnostic value of plasma protein levels. The Mann-Whitney test was used for statistical analysis, (significance (sig) p&amp;lt;0.05). Results: A total of 116 CRC (72% colon, 28% rectal) and 86 benign disease pts (adenoma 31%, diverticulitis 55 %, other 14%) were studied. The male: female ratios were similar but the CRC pts were older (p=0.001). The CRC stage distribution was: stage 1, 33 (28%); stage 2, 33 (28%); stage 3, 41 (36%); stage 4, 9 (8%). The median PreOp plasma PDGF DD level was significantly higher in the CRC group (386.8, CI: 341.2, 498.8) than in the benign disease group (320.4, CI: 281.414.5, p&amp;lt;0.001). No correlation was found between PDGF-DD levels and tumor stage. In sub group analysis, tumor expression of PDGF-DD was confirmed by IHC in 8/10 pts (tumor vs. paired normal tissue). The AUC for the ROC curve (AUC) for plasma PDGF DD in association with a diagnosis of CRC was 0.62751 (sensitivity 29%, specificity 95%). Conclusion: Preoperative plasma PDGF-DD levels were evaluated in CRC pts and compared to those in benign colorectal disease pts. The median plasma PDGF-DD level in CRC pts was 21% higher than the median level in BCD pts. AUC value suggests that PDGF-DD may be a potential candidate for a prognostic marker panel for CRC. The higher levels in CRC pts could be attributed to tumor-related inflammation, progression, and angiogenesis. Further studies with a larger population of cancer free control and CRC pts are necessary to better determine whether PDGF-DD levels correlate with Cancer stage and prognosis. Citation Format: Chandana S K Herath Mudiyanselage, Neil Mitra, Dasuni Niyagama Gamage, Hiromichi Miyagaki, Abhinit Shah, Xiaohong Yan, Vesna Cekic, Richard L. Whelan. Colorectal cancer is associated with elevated plasma levels of soluble platelet-derived growth factor-dd (PDGF-DD) compared to plasma levels of benign colon disease patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3138.

PDGF Receptor Signaling in Osteoblast Lineage Cells Controls Bone Resorption Through Upregulation of Csf1 Expression.

The physiological functions of platelet-derived growth factor receptors (PDGFRs) α and β in osteoblast biology and bone metabolism remain to be established. Here, we show that PDGFRA and PDGFRB genes are expressed by osteoblast-lineage canopy and reversal cells in close proximity to PDGFB-expressing osteoclasts within human trabecular bone remodeling units. We also report that, although removal of only one of the two PDGFRs in Osterix-positive cells does not affect bone phenotype, suppression of both PDGFRs in those osteoblast lineage cells increases trabecular bone volume in male mice as well as in female gonad-intact and ovariectomized mice. Furthermore, osteoblast lineage-specific suppression of PDGFRs reduces Csf1 expression, bone marrow level of macrophage colony-stimulating factor (M-CSF), number of osteoclasts, and, therefore, bone resorption, but does not change bone formation. Finally, abrogation of PDGFR signaling in osteoblasts blocks PDGF-induced ERK1/2-mediated Csf1 expression and M-CSF secretion in osteoblast cultures and calcitriol-mediated osteoclastogenesis in co-cultures. In conclusion, our results indicate that PDGFR signaling in osteoblast lineage cells controls bone resorption through ERK1/2-mediated Csf1 expression. © 2020 American Society for Bone and Mineral Research (ASBMR).

Down-regulation of PDGFRβ suppresses invasion and migration in osteosarcoma cells by influencing epithelial-mesenchymal transition.

Osteosarcoma (OS) is the most common malignant bone tumor primarily influencing children and adults. Approximately one-fifth of patients have micrometastasis in the lungs when OS is diagnosed. Platelet-derived growth factor receptor (PDGFR) beta (PDGFRβ) is a subtype of PDGFR. PDGFRβ has been noted to be highly expressed in OS cell lines and patient specimens, and is associated with metastasis and poor prognosis of OS. However, mechanistic insights into the exact role of PDGFRβ in OS pathogenesis and development are still lacking. Here we assessed the effects of PDGFRβ on invasive and migratory abilities, such as the epithelial-mesenchymal transition and phosphatidylinositol 3-kinase (PI3K), Akt and mammalian target of rapamycin (mTOR) pathways in HOS cells. Depleting PDGFRβ resulted in reduced migration of HOS cells in the small interfering RNA duplexes specific for the PDGFRβ group compared with the mock and scramble-treated groups in Transwell invasion assays. Using wound-healing assays, we demonstrate the rate of wound healing in the PDGF-BB-stimulated group was higher compared with the mock-treated group. Western blot showed that down-regulation of PDGFRβ decreased the expression of stromal phenotype markers and phosphorylation pathway proteins (PI3K, AKT and mTOR), but the epithelial phenotype marker was increased in HOS cells. Treating HOS cells with PDGF-BB revealed a treatment time-dependent increase of phosphorylated, but not total, PI3K, AKT and mTOR. Taken together, we suggest that PDGFRβ plays an important role in OS invasion, migration and epithelial-mesenchymal transition by influencing the PI3K, Akt and mTOR pathways, hence highlighting PDGFRβ as a potential therapeutic target for OS.

Cleavage of proteoglycans, plasma proteins and the platelet-derived growth factor receptor in the hemorrhagic process induced by snake venom metalloproteinases

Envenoming by viperid snakes results in a complex pattern of tissue damage, including hemorrhage, which in severe cases may lead to permanent sequelae. Snake venom metalloproteinases (SVMPs) are main players in this pathogenesis, acting synergistically upon different mammalian proteomes. Hemorrhagic Factor 3 (HF3), a P-III class SVMP from Bothrops jararaca, induces severe local hemorrhage at pmol doses in a murine model. Our hypothesis is that in a complex scenario of tissue damage, HF3 triggers proteolytic cascades by acting on a partially known substrate repertoire. Here, we focused on the hypothesis that different proteoglycans, plasma proteins, and the platelet derived growth factor receptor (PDGFR) could be involved in the HF3-induced hemorrhagic process. In surface plasmon resonance assays, various proteoglycans were demonstrated to interact with HF3, and their incubation with HF3 showed degradation or limited proteolysis. Likewise, Western blot analysis showed in vivo degradation of biglycan, decorin, glypican, lumican and syndecan in the HF3-induced hemorrhagic process. Moreover, antithrombin III, complement components C3 and C4, factor II and plasminogen were cleaved in vitro by HF3. Notably, HF3 cleaved PDGFR (alpha and beta) and PDGF in vitro, while both receptor forms were detected as cleaved in vivo in the hemorrhagic process induced by HF3. These findings outline the multifactorial character of SVMP-induced tissue damage, including the transient activation of tissue proteinases, and underscore for the first time that endothelial glycocalyx proteoglycans and PDGFR are targets of SVMPs in the disruption of microvasculature integrity and generation of hemorrhage.

Life-long Dietary Pesticide Cocktail Induces Astrogliosis Along with Behavioral Adaptations and Activates p450 Metabolic Pathways

Exposure to environmental contaminants is a public health concern. However, pre-clinical studies that examine the impact of pesticides at low-dose and the long-term consequences are uncommon. Here, C57BL6/j male and female mice were daily fed from weaning and up to 12 months, corresponding to early-childhood into middle-age in humans, using chow pellets containing a cocktail of pesticides at tolerable daily intake levels. We found that 12 months of dietary exposure to pesticides was associated with a moderate perenchymal or perivascular astrogliosis in specific hippocampal sub-regions. The expression of platelet-derived growth factor receptor beta was modified at the perivascular level. Examination of Iba1+ microglial cells did not reveal sizeable changes. Concomitantly to astrogliosis, spontaneous spatial memory and sociability were modified in males at 12 months of dietary exposure to pesticides. Telemetry electrocorticograhic explorations ruled out the presence of epileptiform activity or theta-gamma wave modifications in these conditions. Long-term pesticides impacted the periphery where the hepatic P450 metabolic cytochromes Cyp4a14 and Cyp4a10 were significantly upregulated in male and female mice during the 12 months of exposure. The expression of β-oxidation genes, such as Acox1, Cpt1a and Eci, was also significantly increased in male and female mice in response to pesticides. Collectively, our results indicate that a life-long exposure to a pesticide cocktail elicits sex-dependent, spatio-temporally restricted brain modifications and significant activation of P450 pathways in the periphery. These brain-peripheral adjustments are discussed as time or age-dependent vulnerability elements.

The Master of Puppets: Pleiotropy of PDGFRB and its Relationship to Multiple Diseases.

The platelet-derived growth factor receptor beta (PDGFRB) gene is involved in proliferative and developmental processes in mammals. Variations in this gene lead to several different syndromic conditions, such as infantile myofibromatosis I, sporadic port-wine stain, primary familial brain calcification, and the Penttinen and overgrowth syndromes. Our objective was to investigate PDGFRB's genetic relationship to clinical conditions and evaluate the protein interactions using GeneNetwork, GeneMANIA, and STRING network databases. We have evidenced the gene's pleiotropy through its many connections and its link to syndromic conditions. Therefore, PDGFRB may be an important therapeutic target for treating such conditions.

Targeting Activated Hepatic Stellate Cells Using Collagen-Binding Chitosan Nanoparticles for siRNA Delivery to Fibrotic Livers.

Activated hepatic stellate cells (aHSCs) are the main orchestrators of the fibrotic cascade in inflamed livers, with transforming growth factor-beta (TGF-β) being the most potent pro-fibrotic cytokine. Hence, aHSCs serve as interesting therapeutic targets. However, drug delivery to aHSCs is hindered by excessive collagen deposition in the extracellular matrix (ECM) and capillarization of liver sinusoids. Chitosan-nanoparticles (CS-NPs) show intrinsic affinity for collagen, holding potential for drug delivery to fibrotic livers. Here, we employed CS-NPs for anti-TGF-β siRNA delivery, promoting delivery into aHSCs via modification with platelet-derived growth factor receptor-beta binding peptides. In-vitro experiments using aHSCs demonstrated the association of unmodified CS-NPs to the collagen-rich ECM, with reduced intracellular accumulation. Peptide-modified CS-NPs showed a higher propensity to localize intracellularly; however, this was only the case upon ECM-collagen reduction via collagenase treatment. Peptide-modified CS-NPs were more potent than unmodified CS-NPs in reducing TGF-β expression, implying that while collagen binding promotes liver accumulation, it hinders cell-specific siRNA delivery. In-vivo, CS-NPs successfully accumulated in fibrotic livers via collagen binding. Similar to in-vitro findings, when mice were pretreated with collagenase-loaded CS-NPs, the accumulation of peptide-modified NPs increased. Our findings demonstrate the usefulness of NPs modification with targeting ligands and collagenase treatment for aHSCs targeting and highlight the importance of chitosan–collagen binding in drug delivery to fibrotic diseases.

Progress in the correlation between PTPN12 gene expression and human tumors.

Background:The global morbidity of cancer is rising rapidly. Despite advances in molecular biology, immunology, and cytotoxic and immune-anticancer therapies, cancer remains a major cause of death worldwide. Protein tyrosine phosphatase non-receptor type 12 (PTPN12) is a new member of the cytoplasmic protein tyrosine phosphatase family, isolated from a cDNA library of adult colon tissue. Thus far, no studies have reviewed the correlation between PTPN12 gene expression and human tumors.Methods:This article summarizes the latest domestic and international research developments on how the expression of PTPN12 relates to human tumors. The extensive search in Web of Science and PubMed with the keywords including PTPN12, tumor, renal cell carcinoma, proto-oncogenes, tumor suppressor genes was undertaken.Results:More and more studies have shown that a tumor is essentially a genetic disease, arising from a broken antagonistic function between proto-oncogenes and tumor suppressor genes. When their antagonistic effect is out of balance, it may cause uncontrolled growth of cells and lead to the occurrence of tumors. PTPN12 is a tumor suppressor gene, so inhibiting its activity will lead directly or indirectly to the occurrence of tumors.Conclusion:The etiology, prevention, and treatment of tumors have become the focus of research around the world. PTPN12 is a tumor suppressor gene. In the future, PTPN12 might serve as a novel molecular marker to benefit patients, and even the development of tumor suppressor gene activation agents can form a practical research direction.