Platelet-derived Growth Factor Pathway Research Articles

Enhancing cisplatin drug sensitivity through PARP3 inhibition: The influence on PDGF and G-coupled signal pathways in cancer

Drug resistance poses a significant challenge in cancer treatment despite the clinical efficacy of cisplatin. Identifying and targeting biomarkers open new ways to improve therapeutic outcomes. In this study, comprehensive bioinformatic analyses were employed, including a comparative analysis of multiple datasets, to evaluate overall survival and mutation hotspots in 27 base excision repair (BER) genes of more than 7,500 tumors across 23 cancer types.By using various parameters influencing patient survival, revealing that the overexpression of 15 distinct BER genes, particularly PARP3, NEIL3, and TDG, consistently correlated with poorer survival across multiple factors such as race, gender, and metastasis. Single nucleotide polymorphism (SNP) analyses within protein-coding regions highlighted the potential deleterious effects of mutations on protein structure and function. The investigation of mutation hotspots in BER proteins identified PARP3 due to its high mutation frequency.Moving from bioinformatics to wet lab experiments, cytotoxic experiments demonstrated that the absence of PARP3 by CRISPR/Cas9-mediated knockdown in MDA-MB-231 breast cancer cells increased drug activity towards cisplatin, carboplatin, and doxorubicin. Pathway analyses indicated the impact of PARP3 absence on the platelet-derived growth factor (PDGF) and G-coupled signal pathways on cisplatin exposure.PDGF, a critical regulator of various cellular functions, was downregulated in the absence of PARP3, suggesting a role in cancer progression. Moreover, the influence of PARP3 knockdown on G protein-coupled receptors (GPCRs) affects their function in the presence of cisplatin.In conclusion, the study demonstrated a synthetic lethal interaction between GPCRs, PDGF signaling pathways, and PARP3 gene silencing. PARP3 emerged as a promising target.

Ambroxol-induced leukocytoclastic vasculitis: A case report and literature review

Cutaneous leukocytoclastic vasculitis (LCV) that primarily affects the skin, can be idiopathic or linked to infections, autoimmune diseases, neoplasms, and medications. An immune complex-mediated vasculitis of the dermal capillaries and venules is the histological hallmark of LCV, a small vessel vasculitis. This case report describes a 36-year previously healthy man who was presented to the outpatient department (OPD) with complaints of edema and development of numerous reddish-purple patches (caused by petechiae) after intake of cough syrup containing ambroxol. Ambroxol affects human monocytic cells THP-1, and prevents the generation of platelet-derived growth factor (PDGF)-AB that is produced by lipopolysaccharide (LPS) by inhibiting the expression of PDGF-A messenger Ribonucleic acid (RNA). An extracellular signal-regulated kinase (ERK) on p44/42 is activated by LPS, and ambroxol reduces this activation. In addition, 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one (PD 98059), a Mitogen-Activated Protein Kinase Inhibitors (MEK), MEK-1-specific inhibitor, prevents p44/42 ERK activation and PDGF synthesis brought on by LPS. Megakaryocytes, erythrocytes, leukocytes, and their progenitors are stimulated to multiply by PDGF to the numerous endogenous growth factors that mesenchymal stem and stromal cells secrete. Ambroxol reduces the number of megakaryocytic progenitors and boosts apoptosis by inhibiting the production of PDGF and related signaling pathways. It is strongly advised that patients must be made more aware of the risks associated with using such over-the-counter medications.

COVID-19 immune signatures in Uganda persist in HIV co-infection and diverge by pandemic phase

Little is known about the pathobiology of SARS-CoV-2 infection in sub-Saharan Africa, where severe COVID-19 fatality rates are among the highest in the world and the immunological landscape is unique. In a prospective cohort study of 306 adults encompassing the entire clinical spectrum of SARS-CoV-2 infection in Uganda, we profile the peripheral blood proteome and transcriptome to characterize the immunopathology of COVID-19 across multiple phases of the pandemic. Beyond the prognostic importance of myeloid cell-driven immune activation and lymphopenia, we show that multifaceted impairment of host protein synthesis and redox imbalance define core biological signatures of severe COVID-19, with central roles for IL-7, IL-15, and lymphotoxin-α in COVID-19 respiratory failure. While prognostic signatures are generally consistent in SARS-CoV-2/HIV-coinfection, type I interferon responses uniquely scale with COVID-19 severity in persons living with HIV. Throughout the pandemic, COVID-19 severity peaked during phases dominated by A.23/A.23.1 and Delta B.1.617.2/AY variants. Independent of clinical severity, Delta phase COVID-19 is distinguished by exaggerated pro-inflammatory myeloid cell and inflammasome activation, NK and CD8+ T cell depletion, and impaired host protein synthesis. Combining these analyses with a contemporary Ugandan cohort of adults hospitalized with influenza and other severe acute respiratory infections, we show that activation of epidermal and platelet-derived growth factor pathways are distinct features of COVID-19, deepening translational understanding of mechanisms potentially underlying SARS-CoV-2-associated pulmonary fibrosis. Collectively, our findings provide biological rationale for use of broad and targeted immunotherapies for severe COVID-19 in sub-Saharan Africa, illustrate the relevance of local viral and host factors to SARS-CoV-2 immunopathology, and highlight underemphasized yet therapeutically exploitable immune pathways driving COVID-19 severity.

Using the Bayesian variational spike and slab model in a genome-wide association study for finding associated loci with bipolar disorder.

The genome-wide association studies (GWAS) analysis, the most successful technique for discovering disease-related genetic variation, has some statistical concerns, including multiple testing, the correlation among variants (single-nucleotide polymorphisms) based on linkage disequilibrium and omitting the important variants when fitting the model with just one variant. To eliminate these problems in a small sample-size study, we used a sparse Bayesian learning model for finding bipolar disorder (BD) genetic variants. This study used the Wellcome Trust Case Control Consortium data set, including 1998 BD cases and 1500 control samples, and after quality control, 380,628 variants were analysed. In this GWAS, a Bayesian logistic model with hierarchical shrinkage spike and slab priors was used, with all variants considered simultaneously in one model. In order to decrease the computational burden, an alternative inferential method, Bayesian variational inference, has been used. Thirteen variants were selected as associated with BD. The three of them (rs7572953, rs1378850 and rs4148944) were reported in previous GWAS. Eight of which were related to hemogram parameters, such as lymphocyte percentage, plateletcrit and haemoglobin concentration. Among selected related genes, GABPA, ELF3 and JAM2 were enriched in the platelet-derived growth factor pathway. These three genes, along with APP, ARL8A, CDH23 and GPR37L1, could be differential diagnostic variants for BD. By reducing the statistical restrictions of GWAS analysis, the application of the Bayesian variational spike and slab models can offer insight into the genetic link with BD even with a small sample size. To uncover related variations with other traits, this model needs to be further examined.

Garlic Exosomes Promote Hair Growth Through the Wnt/β-catenin Pathway and Growth Factors.

Background Exosomes are membrane-derived nanovesicles produced by cells and play an important role in intercellular communication. Objectives This study aimed to investigate the effects of garlic exosome (GE) on hair growth. Methods Forty-two Sprague-Dawley/Wistar albino rats were randomly divided into six groups: non-shaved control, shaved control, topical control, GE 2 mg, GE 4 mg, and topical GE. At the end of the experiment, the number of hair follicles, follicle diameter, and subcutaneous tissue thicknesses were measured histopathologically. The Wnt-1, β-catenin, platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1), and collagen I levels were measured by the Western Blot method. Results The anagen follicle counts of the GE 2 mg, 4 mg, and topical GE groups were 66.57±15.49, 105.71±25.06, and 55.29±6.72, and were significantly higher than the control groups (p<0.01, p<0.001 and p<0.05, respectively). The follicle diameter of the GE 4 mg group was higher than the others (p<0.05). The Wnt-1, PDGF, VEGF, TGF-β1, and collagen I levels of all GE groups, and the β-catenin levels of the GE 4 mg and topical GE groups were significantly higher than the control groups (p<0.05). Conclusion GE induces hair growth in rats via the Wnt-1, β-catenin, VEGF, PDGF, and TGF-β1 signaling pathways.

Gastroprotective effect of dapagliflozin in ethanol-induced gastric lesions in rats: Crosstalk between HMGB1/RAGE/PTX3 and TLR4/MyD88/VEGF/PDGF signaling pathways.

Alcohol abuse may lead to the development of gastric mucosal lesions. Dapagliflozin (DAPA), a sodium-glucose cotransporter-2 inhibitor, is clinically used to treat type 2 diabetes mellitus. However, studies showed protective effect of DAPA under various experimental conditions by alleviating oxidative stress and inflammation. The effect of DAPA on experimental gastric ulcer has not been studied yet. Therefore, we attempted to investigate DAPA's protective effect against ethanol (EtOH)-induced gastric lesions. Fifty-six (8-week-old) male Wistar rats were divided into seven groups. DAPA (1, 5, and 10mg/kg/day; p.o.) was given for seven days, plus a single dose of absolute EtOH (5ml/kg) on day 8. According to hematoxylin and eosin, and Alcian blue staining of gastric tissue sections, titratable acidity, and macroscopic assessments, DAPA high dose (10mg/kg) was the most protective, with lesser ulcerations, and higher mucin, relative to the lower two doses and the standard treatment omeprazole (OME). In rats pre-treated with DAPA high dose, colorimetric and ELISA analyses revealed significantly decreased oxidative stress, pro-inflammatory, and apoptosis indices and increased levels of platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF). Western blot analysis revealed reduced pentraxin-3 (PTX3), high-mobility group box 1 (HMGB1), receptor for advanced glycation end products (RAGE), toll-like receptor 4 (TLR4), and myeloid differentiation factor 88 (MyD88) expression. These results were comparable in DAPA (10mg/kg) and OME pre-treated groups. Overall, DAPA exerted a dose-dependent protective effect against EtOH-induced gastric injury. Gastroprotective effects of DAPA (10mg/kg) may be associated with influencing HMGB1/RAGE/PTX3 and TLR4/MyD88/VEGF/PDGF pathways.

Hedgehog and Platelet-derived Growth Factor Signaling Intersect during Postnatal Lung Development.

Normal lung development critically depends on HH (Hedgehog) and PDGF (platelet-derived growth factor) signaling, which coordinate mesenchymal differentiation and proliferation. PDGF signaling is required for postnatal alveolar septum formation by myofibroblasts. Recently, we demonstrated a requirement for HH in postnatal lung development involving alveolar myofibroblast differentiation. Given shared features of HH signaling and PDGF signaling and their impact on this key cell type, we sought to clarify their relationship during murine postnatal lung development. Timed experiments revealed that HH inhibition phenocopies the key lung myofibroblast phenotypes of Pdgfa (platelet-derived growth factor subunit A) and Pdgfra (platelet-derived growth factor receptor alpha) knockouts during secondary alveolar septation. Using a dual signaling reporter, Gli1lZ;PdgfraEGFP, we show that HH and PDGF pathway intermediates are concurrently expressed during alveolar septal myofibroblast accumulation, suggesting pathway convergence in the generation of lung myofibroblasts. Consistent with this hypothesis, HH inhibition reduces Pdgfra expression and diminishes the number of Pdgfra-positive and Pdgfra-lineage cells in postnatal lungs. Bulk RNA sequencing data of Pdgfra-expressing cells from Postnatal Day 8 (P8) lungs show that HH inhibition alters the expression not only of well-established HH targets but also of several putative PDGF target genes. This, together with the presence of Gli-binding sites in PDGF target genes, suggests HH input into PDGF signaling. We identified these HH/PDGF targets in several postnatal lung mesenchymal cell populations, including myofibroblasts, using single-cell transcriptomic analysis. Collectively, our data indicate that HH signaling and PDGF signaling intersect to support myofibroblast/fibroblast function during secondary alveolar septum formation. Moreover, they provide a molecular foundation relevant to perinatal lung diseases associated with impaired alveolarization.

Inhibition of platelet-derived growth factor pathway suppresses tubulointerstitial injury in renal congestion.

Objective:Increased central venous pressure in congestive heart failure is responsible for renal dysfunction, which is mediated by renal venous congestion. Pericyte detachment from capillaries after renal congestion might trigger renal fibrogenesis via pericyte-myofibroblast transition (PMT). Platelet-derived growth factor receptors (PDGFRs), which are PMT indicators, were upregulated in our recently established renal congestion model. This study was designed to determine whether inhibition of the PDGFR pathway could suppress tubulointerstitial injury after renal congestion.Methods:The inferior vena cava between the renal veins was ligated in male Sprague-Dawley rats, inducing congestion only in the left kidney. Imatinib mesylate or vehicle were injected intraperitoneally daily from 1 day before the operation. Three days after the surgery, the effect of imatinib was assessed by physiological, morphological and molecular methods. The inhibition of PDGFRs against transforming growth factor-β1 (TGFB1)-induced fibrosis was also tested in human pericyte cell culture.Results:Increased kidney weight and renal fibrosis were observed in the congested kidneys. Upstream inferior vena cava (IVC) pressure immediately increased to around 20 mmHg after IVC ligation in both the imatinib and saline groups. Although vasa recta dilatation and pericyte detachment under renal congestion were maintained, imatinib ameliorated the increased kidney weight and suppressed renal fibrosis around the vasa recta. TGFB1-induced elevation of fibrosis markers in human pericytes was suppressed by PDGFR inhibitors at the transcriptional level.Conclusion:The activation of the PDGFR pathway after renal congestion was responsible for renal congestion-induced fibrosis. This mechanism could be a candidate therapeutic target for renoprotection against renal congestion-induced tubulointerstitial injury.

Sodium pentaborate pentahydrate promotes hair growth through the Wnt/β-catenin pathway and growth factors

BackgroundBoron (B) is an element involved in many physiological processes in humans and accelerates wound healing and increases angiogenesis. This study aimed to evaluate the possible effects of sodium pentaborate pentahydrate (NaB) on hair growth and reveal its effects on Wnt-1, β-catenin, vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and transforming growth factor-β1 (TGF-β1) signaling pathways, which are important molecular mechanisms involved in hair growth. MethodsThirty-five Sprague-Dawley/Wistar albino rats were randomly divided into five groups: non-shaved control, shaved control, NaB 1 mg (shaved + NaB 1 mg elemental B/kg CA), NaB 2 mg (shaved + NaB 2 mg elemental B/kg CA), and NaB 4 mg (shaved + NaB 4 mg elemental B/kg CA). Hair density was measured using the trichoscopy method. Dorsal skin samples were examined histopathologically at the end of the 42nd day, and follicle count, follicle diameter, and subcutaneous tissue thickness were recorded. Wnt-1, β-catenin, PDGF, VEGF, TGF-β1, and collagen I levels were analyzed with the Western blot method. ResultsIn trichoscopy measurements, hair density increased in the NaB 4 mg group (90.9%). In histopathological examination, anagen follicles were observed to increase in the NaB 1 mg and 2 mg groups (p < 0.05). Follicle diameter increased in all NaB groups (p < 0.05). The Wnt-1, β-catenin, PDGF, VEGF, TGF-β1, and collagen I level increased in the NaB 1 mg and 2 mg groups (p < 0.05), but they were similar in the NaB 4 mg group compared to the control groups (p > 0.05). ConclusionNaB 1 and 2 mg B/kg supplementation induces the anagen phase in rats via Wnt-1, β-catenin, VEGF, PDGF, and TGF-β1 signaling pathways. NaB 4 mg B/kg suppresses these pathways and adversely affects hair growth.

The Platelet-Derived Growth Factor Pathway in Pulmonary Arterial Hypertension: Still an Interesting Target?

The lack of curative options for pulmonary arterial hypertension drives important research to understand the mechanisms underlying this devastating disease. Among the main identified pathways, the platelet-derived growth factor (PDGF) pathway was established to control vascular remodeling and anti-PDGF receptor (PDGFR) drugs were shown to reverse the disease in experimental models. Four different isoforms of PDGF are produced by various cell types in the lung. PDGFs control vascular cells migration, proliferation and survival through binding to their receptors PDGFRα and β. They elicit multiple intracellular signaling pathways which have been particularly studied in pulmonary smooth muscle cells. Activation of the PDGF pathway has been demonstrated both in patients and in pulmonary hypertension (PH) experimental models. Tyrosine kinase inhibitors (TKI) are numerous but without real specificity and Imatinib, one of the most specific, resulted in beneficial effects. However, adverse events and treatment discontinuation discouraged to pursue this therapy. Novel therapeutic strategies are currently under experimental evaluation. For TKI, they include intratracheal drug administration, low dosage or nanoparticles delivery. Specific anti-PDGF and anti-PDGFR molecules can also be designed such as new TKI, soluble receptors, aptamers or oligonucleotides.

Identifying the Potential Role and Prognostic Value of the Platelet-Derived Growth Factor Pathway in Kidney Renal Clear Cell Carcinoma.

The platelet-derived growth factor (PDGF) pathway is important in angiogenesis, which can accelerate the formation of vessels in tumor tissues and promote the progression of malignant tumors. To clarify the role of PDGF in the occurrence of renal cell carcinoma and targeted drug resistance, we explored the pathway in kidney renal clear cell carcinoma (KIRC) through bioinformatics analysis with the aim of supporting comprehensive and individualized therapy. First, we found 40 genes related to the PDGF pathway through gene set enrichment analysis and then obtained their expressions and clinical data in 32 different cancers from The Cancer Genome Atlas (TCGA). Mutations in these genes (including copy number and single-nucleotide variation) and mRNA expression were also detected. Next, we conducted a hazard ratio analysis to determine whether the PDGF pathway genes were risk or protective factors in tumors. Although PDGF-related genes acted as traditional oncogenes and were closely related to tumor angiogenesis in many cancers, our results indicated that most genes had a protective role in KIRC. We further analyzed the methylation modification of PDGF pathway genes and found that they were prevalent in 32 different cancers. Furthermore, 539 KIRC samples obtained from TCGA were divided into three clusters based on the mRNA expression of PDGF genes, including normal, inactive, and active PDGF gene expressions. The results from survival curve analysis indicated that the active PDGF cluster of patients had the best survival rate. Using the three clusters, we studied the correlation between the PDGF pathway and 12 common targeted drugs, as well as classical oncogenes and infiltrating immune cells. A prognostic risk model was constructed based on the PDGF score using LASSO-Cox regression analysis to analyze the value of the model in predicting the prognosis of patients with KIRC. Finally, 11 genes were selected for LASSO regression analysis, and the results demonstrated the high predictive value of this risk model and its close relationship with the pathological characteristics of KIRC (metastasis, size, grade, stage, etc.). In addition, we found that the risk score was an independent risk factor correlated with overall survival through univariate and multivariate analyses and a nomogram was built to assess patient prognosis. In conclusion, the occurrence and development of KIRC may be associated with an abnormally activated PDGF pathway, which may be a potential drug target in the treatment of KIRC.

Heterogeneity of Platelet Derived Growth Factor Pathway Gene Expression Profile Defines Three Distinct Subgroups of Renal Cell Carcinomas.

We previously described four different vascular patterns (reticular, diffuse, fasciculate, and trabecular) in renal cell carcinoma (RCC) suggesting an early and heterogeneous acquisition of perivascular cells most probably due to a particular PDGF pathway gene expression profile. The aim of the study was to study PDGF pathway gene expression profiles, separately for each vascular pattern. TaqMan assay for the PDGF pathway was performed on twelve cases of ccRCC previously evaluated by histopathology, immunohistochemistry, and RNAscope. Gene expression profile was correlated with grade, invasion, vascular patterns, and VEGF. PIK3C3 and SLC9A3 genes were overexpressed in all vascular patterns, but they were significantly correlated with high VEGF mRNA in the reticular and diffuse pattern. STAT1, JAK2, SHC2, SRF and CHUK (IKK) were exclusively overexpressed in cases with diffuse vascular pattern. SLC9A3, CHUK and STAT3 were overexpressed in G2 tumors. Three ccRCC subgroups were defined: 1) PIK3C3 (VSP34)/SLC9A3 which may be proper for anti PIK3C3 inhibitors; 2) VEGFhigh subgroup where association of anti VEGF may be a benefit and 3) JAK2/STAT1 subgroup, potentially being eligible for anti JAK/STAT therapy associated with IKK inhibitors.

MiR-211-5p Inhibits the Biological Behaviors of Colorectal Cancer via SPARC-Related Growth Factor Pathways.

Colorectal cancer (CRC) is a highly malignant cancer with poor prognosis. MiR-211-5p has been widely studied as an antioncogene; however, its function and mechanism in CRC are still unknown. This study aimed to investigate the expression patterns and biological implications of miR-211-5p in CRC. This study used quantitative real-time polymerase chain reaction to evaluate miR-211-5p expression in CRC cells and tissues. MiR-211-5p mimics were constructed to overexpress miR-211-5p in Lovo and SW480 cells. Tumor bioactivities of CRC, including cell proliferation, migration, invasion, and colony formation, were evaluated. The dual-luciferase assay was used to confirm the targeted relationship between miR-211-5p expression and secreted protein acidic and rich in cysteine (SPARC). In addition, Western blot analysis and immunohistochemical staining were used to measure SPARC, platelet-derived growth factor (PDGF), transforming growth factor β (TGF-β), and vascular endothelial growth factor (VEGF) expression levels. This study showed downregulated miR-211-5p expression in CRC cells and tissues, and this downregulation correlated with CRC progression. Meanwhile, miR-211-5p restrained CRC cell proliferation, colony formation, migration, and invasion. Mechanistically, SPARC-related growth factor pathways, including VEGF, PDGF, and TGF-β pathways, were upregulated in CRC tissues. Furthermore, SPARC acted as the target gene for miR-211-5p. Finally, SPARC overexpression suppressed the inhibitory effect of miR-211-5p on CRC cell progression. MiR-211-5p suppressed the invasion, migration, proliferation, and progression of CRC cells through sponging SPARC-related growth factor pathways.

Liver Fibrosis: Underlying Mechanisms and Innovative Therapeutic Approach. A Review Article

Liver fibrosis is considered: “a pathological repairing process in liver injuries leading to extracellular cell matrix (ECM) accumulation evidencing chronic liver diseases”. Chronic viral hepatitis, alcohol consumption, autoimmune diseases as well as non-alcoholic steatohepatitis are from the main causes of liver fibrosis (Lee et al., 2015; Mieli-Vergani et al., 2018). Hepatic stellate cells (HSCs) exist in the sinus space next to the hepatic epithelial cells as well as endothelial cells (Yin et al., 2013). Normally, HSCs are quiescent and mainly participate in fat storage and in the metabolism of vitamin A. HSCs are produced during liver injury and then transformed into myofibroblasts. The activated HSCs resulted in a sequence of events considered as marks fibrosis. The activation of HSCs mostly express alpha smooth muscle actin (α-SMA). Moreover, ECM is synthesized and secreted by HSCs that affects markedly the structure and function of the liver tissue leading to fibrosis (Tsuchida et al., 2017; Han et al., 2020). Hence, activated HSCs are attracting attention as potential targets in liver fibrosis. Many signaling molecules are involved in HSCs activation first and foremost, platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-β) (Tsuchida et al., 2017; Wang et al., 2020c) as interfering the PDGF or TGF-β signaling pathways is a growing field for liver fibrosis treatment.

Cardiovascular safety of the tyrosine kinase inhibitor nintedanib.

The intracellular tyrosine kinase inhibitor nintedanib has shown great efficacy for the treatment of idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases. However, the incidence rate of myocardial infarction (MI) among participants in landmark IPF trials was remarkable, peaking at 3/100 patient-years. Although subjects with IPF often have a high cardiovascular (CV) risk profile, the occurrence of MI in nintedanib-treated patients may not be fully explained by clustering of CV risk factors. Nintedanib inhibits the vascular endothelial growth factor, platelet-derived growth factor and fibroblast growth factor pathways, which play important roles in the biology of the atherosclerotic plaque and in the response of the heart to ischaemia. Hence, unwanted CV effects may partly account for nintedanib-related MI. We review the evidence supporting this hypothesis and discuss possible actions for a safe implementation of nintedanib in clinical practice, building on the experience with tyrosine kinase inhibitors acquired in cardio-oncology.

Murine Precision-cut Intestinal Slices as a Potential Screening Tool for Antifibrotic Drugs.

BackgroundIntestinal fibrosis is a hallmark of Crohn’s disease. Here, we investigated the impact of several putative antifibrotic compounds on the expression of fibrosis markers using murine precision-cut intestinal slices.MethodsMurine precision-cut intestinal slices were cultured for 48 hours in the presence of profibrotic and/or antifibrotic compounds. The fibrotic process was studied on gene and protein level using procollagen 1a1 (Col1α1), heat shock protein 47 (Hsp47), fibronectin (Fn2), and plasminogen activator inhibitor-1 (Pai-1). The effects of potential antifibrotic drugs mainly inhibiting the transforming growth factor β (TGF-β) pathway (eg, valproic acid, tetrandrine, pirfenidone, SB203580, and LY2109761) and compounds mainly acting on the platelet-derived growth factor (PDGF) pathway (eg, imatinib, sorafenib, and sunitinib) were assessed in the model at nontoxic concentrations.ResultsMurine precision-cut intestinal slices remained viable for 48 hours, and an increased expression of fibrosis markers was observed during culture, including Hsp47, Fn2, and Pai-1. Furthermore, TGF-β1 stimulated fibrogenesis, whereas PDGF did not have an effect. Regarding the tested antifibrotics, pirfenidone, LY2109761, and sunitinib had the most pronounced impact on the expression of fibrosis markers, both in the absence and presence of profibrotic factors, as illustrated by reduced levels of Col1α1, Hsp47, Fn2, and Pai-1 after treatment. Moreover, sunitinib significantly reduced Hsp47 and Fn2 protein expression and the excretion of procollagen 1.ConclusionsPrecision-cut intestinal slices can successfully be used as a potential preclinical screening tool for antifibrotic drugs. We demonstrated that sunitinib reduced the expression of several fibrosis markers, warranting further evaluation of this compound for the treatment of intestinal fibrosis.

Activation of PDGF pathway links LMNA mutation to dilated cardiomyopathy.

Lamin A/C (LMNA) is one of the most frequently mutated genes in dilated cardiomyopathy (DCM). LMNA-related DCM is a common inherited cardiomyopathy associated with systolic dysfunction and high prevalence arrhythmias. Here we modeled the LMNA-DCM in vitro using patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Electrophysiological studies showed that the mutant iPSC-CMs displayed aberrant calcium homeostasis leading to arrhythmias at the single-cell level. Mechanistically, we uncovered that the platelet-derived growth factor (PDGF) signaling pathway was activated in mutant iPSC-CMs when compared to isogenic controls. Conversely, pharmacological and molecular inhibition of the PDGF signaling pathway ameliorated the arrhythmia phenotypes of mutant iPSC-CMs in vitro. Taken together, our findings suggest that the activation of the PDGF pathway contributes to the pathogenesis of the LMNA-DCM and point to PDGF receptor beta (PDGFRB) as a potential therapeutic target.

β-catenin-activated autocrine PDGF/Src signaling is a therapeutic target in pancreatic cancer.

K-ras mutation and p53 loss are the most prevalent genetic alterations in pancreatic cancer. In addition to these two alterations, pancreatic tumors frequently contain a third genetic defect. Mutations in the WNT/ß-catenin signaling molecules occur in 15-20% of pancreatic cancer patients and co-exist with K-ras mutation and p53 loss. However, the contribution of the WNT/ß-catenin pathway in pancreatic tumorigenesis is still unclear.Methods: We generated Pdx1-CreKrasG12Dp53L/+APCL/+ (KPA) mice and compared their phenotypes with Pdx1-CreKrasG12Dp53L/+ (KPC) mice. The signaling pathways specifically activated in the KPA mice were investigated and the therapeutic effect by targeting the activated pathways was evaluated. We finally validated our findings in human blood and tumor samples.Results: Survival of the KPA mice was shorter than that of the KPC mice. The KPA cancer cells are highly invasive and exhibit distorted morphology in organoid culture with extensive invadopodia formation and elevated matrix metalloproteinase (MMP) activity. The platelet-derived growth factor (PDGF) pathway is upregulated in the KPA cancer cells, and PDGF production induced by ß-catenin triggers constitutive activation of the Src kinase via the PDGF receptor in the cells. Serum PDGF concentration of the KPA mice is much higher than that of the normal and KPC mice. The Src inhibitor dasatinib effectively inhibits tumor growth and metastasis of the KPA cancer cells. Patient's serum PDGF level is significantly correlated with the expression of PDGF and phosphor-Src in tumors and elevated PDGF/phosphor-Src level in tumors predicts increased recurrence and poor survival. Moreover, mutations of the WNT/ß-catenin signaling molecules are higher in patients with elevated PDGF/phosphor-Src level.Conclusion: ß-catenin activation, coupled with K-ras mutation and p53 loss, activates an autocrine PDGF/Src signaling in pancreatic cancer and defines a subset of patients who might be sensitive to Src inhibition. In addition, serum PDGF level could be a reliable biomarker for patient selection in clinic.

Platelet-derived growth factor in patients with liver fibrosis

Objective To asses the changes in platelet-derived growth factor (PDGF) in liver fibrosis. Data sources The data were sourced from the PubMed database from the start of the database to 2017 and from all materials available in the Internet. Study selection The initial search presented 423 articles of which 39 met the inclusion criteria. The articles studied the relation between PDGF and liver fibrosis. Data extraction If the studies did not fulfill the inclusion criteria, they were excluded. Study quality assessment included when ethical approval was obtained, eligibility criteria defined, sufficient information, convenient controls, and known assessment measures. Data synthesis Comparisons were made through structured review with the results tabulated. Findings In total, 39 potentially relevant publications were included. The studies indicate an association between PDGF and liver fibrosis as PDGF increases in patients with hepatic fibrosis and correlates well with the grade of fibrosis. The majority of studies were performed on the effect of PDGF antagonists on liver fibrosis and they found that interference of PDGF pathway leads to reduction of liver fibrosis. Conclusion We found that PDGF levels increase in patients with liver fibrosis and its level correlates well with the stage of fibrosis; thus, PDGF can be used as a potential noninvasive marker for liver fibrosis either alone or in association with other fibrosis markers. Further, antagonizing the pathway of PDGF may offer a promising strategy for the treatment of liver fibrosis.

Assembly of fibronectin fibrils selectively attenuates platelet-derived growth factor–induced intracellular calcium release in fibroblasts

Cellular responses to platelet-derived growth factor (PDGF) are altered in a variety of pathological conditions, including cancers, fibroses, and vascular diseases, making PDGF-induced signaling pathways important therapeutic targets. The limited success of therapies designed to impact PDGF pathways may be overcome with a clearer understanding of how cells integrate signals from PDGF and the extracellular matrix (ECM). Here, we assessed the effects of fibronectin matrix assembly on the responsiveness of mesenchymal cells to PDGF. Our results indicate that fibroblast-mediated assembly of fibronectin fibrils attenuates intracellular calcium release in response to PDGF. The dose-dependent inhibition of PDGF-induced intracellular calcium release was specific to the ECM form of fibronectin. Further, a recombinant protein engineered to mimic ECM fibronectin similarly attenuated intracellular calcium release in response to PDGF. Of note, fibronectin attenuated the PDGF-calcium signaling axis at the level of phosphoinositide 3-kinase (PI3K) activation. Interestingly, ECM fibronectin did not alter other intracellular signals activated by PDGF, including activation of PDGF receptor β, AKT Ser/Thr kinase, phospholipase Cγ1, and extracellular signal-regulated kinase 1/2 (ERK1/2). Rather, fibronectin inhibited activation of the p55 regulatory subunit of PI3K in response to a variety of stimuli, indicating that ECM fibronectin selectively attenuates the intracellular calcium release cascade while leaving intact other PDGF signaling pathways. Selective regulation of calcium signaling by ECM fibronectin via the p55 regulatory subunit of PI3K represents a mechanism by which cells tune their response to PDGF and may therefore serve as a target to selectively regulate one branch of PDGF signaling.