Platelet-derived Growth Factor Signaling Research Articles

Corosolic acid attenuates platelet-derived growth factor signaling in macrophages and smooth muscle cells of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive and life-threatening disease that is characterized by vascular remodeling of the pulmonary artery. Pulmonary vascular remodeling is primarily caused by the excessive proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs), which are facilitated by perivascular inflammatory cells including macrophages. Corosolic acid (CRA) is a natural pentacyclic triterpenoid that exerts anti-inflammatory effects. In the present study, the effects of CRA on the viability of macrophages were examined using monocrotaline (MCT)-induced PAH rats and human monocyte-derived macrophages. Although we previously reported that CRA inhibited signal transducer and activator of transcription 3 (STAT3) signaling and ameliorated pulmonary vascular remodeling in PAH, the inhibitory mechanism remains unclear. Therefore, the underlying mechanisms were investigated using PASMCs from idiopathic PAH (IPAH) patients. In MCT-PAH rats, CRA inhibited the accumulation of macrophages around remodeled pulmonary arteries. CRA reduced the viability of human monocyte-derived macrophages. In IPAH-PASMCs, CRA attenuated cell proliferation and migration facilitated by platelet-derived growth factor (PDGF)-BB released from macrophages and PASMCs. CRA also downregulated the expression of PDGF receptor β and its signaling pathways, STAT3 and nuclear factor-κB (NF-κB). In addition, CRA attenuated the phosphorylation of PDGF receptor β and STAT3 following the PDGF-BB simulation. The expression and phosphorylation levels of PDGF receptor β after the PDGF-BB stimulation were reduced by the small interfering RNA knockdown of NF-κB, but not STAT3, in IPAH-PASMCs. In conclusion, CRA attenuated the PDGF-PDGF receptor β-STAT3/NF-κB signaling axis in macrophages and PASMCs, and thus, ameliorated pulmonary vascular remodeling in PAH.

Targeting PDGF signaling of cancer-associated fibroblasts blocks feedback activation of HIF-1α and tumor progression of clear cell ovarian cancer.

Ovarian clear cell carcinoma (OCCC) is a gynecological cancer with a dismal prognosis; however, the mechanism underlying OCCC chemoresistance is not well understood. To explore the intracellular networks associated with the chemoresistance, we analyze surgical specimens by performing integrative analyses that combine single-cell analyses and spatial transcriptomics. We find that a chemoresistant OCCC subpopulation with elevated HIF activity localizes mainly in areas populated by cancer-associated fibroblasts (CAFs) with a myofibroblastic phenotype, which is corroborated by quantitative immunostaining. CAF-enhanced chemoresistance and HIF-1α induction are recapitulated in co-culture assays, which show that cancer-derived platelet-derived growth factor (PDGF) contributes to the chemoresistance and HIF-1α induction via PDGF receptor signaling in CAFs. Ripretinib is identified as an effective receptor tyrosine kinase inhibitor against CAF survival. In the co-culture system and xenograft tumors, ripretinib prevents CAF survival and suppresses OCCC proliferation in the presence of carboplatin, indicating that combination of conventional chemotherapy and CAF-targeted agents is effective against OCCC.

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.

Platelet-derived growth factor signaling in pericytes promotes hypothalamic inflammation and obesity.

Pericytes are a vital component of the blood-brain barrier, and their involvement in acute inflammation was recently suggested. However, it remains unclear whether pericytes contribute to hypothalamic chronic inflammation and energy metabolism in obesity. The present study investigated the impact of pericytes on the pathophysiology of obesity by focusing on platelet-derived growth factor (PDGF) signaling, which regulates pericyte functions. Tamoxifen-inducible systemic conditional PDGF receptor β knockout mice (Pdgfrb∆SYS-KO) and Calcium/calmodulin-dependent protein kinase type IIa (CaMKIIa)-positive neuron-specific PDGF receptor β knockout mice (Pdgfrb∆CaMKII-KO) were fed a high-fat diet, and metabolic phenotypes before and 3 to 4weeks after dietary loading were examined. Intracellular energy metabolism and relevant signal transduction in lipopolysaccharide- and/or platelet-derived growth factor-BB (PDGF-BB)-stimulated human brain pericytes (HBPCs) were assessed by the Seahorse XFe24 Analyzer and Western blotting. The pericyte secretome in conditioned medium from HBPCs was studied using cytokine array kit, and its impact on polarization was examined in bone marrow-derived macrophages (BMDMs), which are microglia-like cells. Energy consumption increased and body weight gain decreased after high-fat diet loading in Pdgfrb∆SYS-KO mice. Cellular oncogene fos (cFos) expression increased in proopiomelanocortin (POMC) neurons, whereas microglial numbers and inflammatory gene expression decreased in the hypothalamus of Pdgfrb∆SYS-KO mice. No significant changes were observed in Pdgfrb∆CaMKII-KO mice. In HBPCs, a co-stimulation with lipopolysaccharide and PDGF-BB shifted intracellular metabolism towards glycolysis, activated mitogen-activated protein kinase (MAPK), and modulated the secretome to the inflammatory phenotype. Consequently, the secretome showed an increase in various proinflammatory chemokines and growth factors including Epithelial-derived neutrophil-activating peptide 78 (C-X-C motif chemokine ligand (CXCL)5), Thymus and activation-regulated chemokine (C-C motif chemokine (CCL)17), Monocyte chemoattractant protein 1 (CCL2), and Growth-regulated oncogene α (CXCL1). Furthermore, conditioned medium from HBPCs stimulated the inflammatory priming of BMDMs, and this change was abolished by the C-X-C motif chemokine receptor (CXCR) inhibitor. Consistently, mRNA expression of CXCL5 was elevated by lipopolysaccharide and PDGF-BB treatment in HBPCs, and the expression was significantly lower in the hypothalamus of Pdgfrb∆SYS-KO mice than in control Pdgfrbflox/flox mice (FL) following 4 weeks of HFD feeding. PDGF receptor β signaling in hypothalamic pericytes promotes polarization of macrophages by changing their secretome and contributes to the progression of obesity.

[Buyang Huanwu Decoction promotes arteriogenesis after hindlimb ischemia in mice by activating PDGF signaling pathway].

This study aims to investigate the effect of Buyang Huanwu Decoction on blood flow recovery and arteriogenesis after hindlimb ischemia in mice via the platelet-derived growth factor(PDGF) signaling pathway. Forty C57BL/6 mice were randomized into model(clean water, 10 mL·kg~(-1)·d~(-1)), beraprost sodium(positive control, 18 μg·kg~(-1)·d~(-1)), and low-, medium-, and high-dose(10, 20, and 40 g·kg~(-1)·d~(-1), respectively) Buyang Huanwu Decoction groups(n=8). The hindlimb ischemia model was established by femoral artery ligation. The mice were administrated with corresponding agents by gavage daily for 14 days after ligation. For laser Doppler perfusion imaging, the mice were anesthetized and measured under a Periscan PSI imager. The density of capillary and arterio-le in the ischemic gastrocnemius was measured using immunofluorescence staining of the frozen tissue sections. Western blot was employed to determine the expression of PDGF subunit B(PDGFB), phosphorylated mitogen extracellular kinase(p-MEK), MEK, phosphorylated extracellular signal-regulated kinase(p-ERK), and ERK. Real-time PCR was employed to determine the mRNA level of PDGFB. The Buyang Huanwu Decoction-containing serum was used to treat the vascular smooth muscle cells(VSMCs) in hypoxia at doses of 10% and 20%. The proliferation and migration of VSMCs was assessed in vitro. The results showed that compared with the model group, beraprost sodium and Buyang Huanwu Decoction enhanced the blood flow recovery, increased the capillary and arteriole density, and up-regulated the protein levels of PDGFB, p-MEK, p-ERK, and mRNA levels of PDGFB, with the medium-dose Buyang Huanwu Decoction demonstrating the most significant effect. The 10% Buyang Huanwu Decoction-containing serum enhanced the proliferation and migration of VSMCs. Our findings demonstrate that Buyang Huanwu Decoction up-regulates PDGFB transcription and activates PDGF signaling pathway to promote arteriogenesis and blood flow recovery in ischemic gastrocnemius.

Stiffness-induced cancer-associated fibroblasts are responsible for immunosuppression in a platelet-derived growth factor ligand-dependent manner.

Pancreatic ductal adenocarcinoma (PDAC) is associated with a vast stromal reaction that arises mainly from cancer-associated fibroblasts (CAFs) and promotes both immune escape and tumor growth. Here, we used a mouse model with deletion of the activin A receptor ALK4 in the context of the KrasG12D mutation, which strongly drives collagen deposition that leads to tissue stiffness. By ligand-receptor analysis of single-cell RNA-sequencing data, we identified that, in stiff conditions, neoplastic ductal cells instructed CAFs through sustained platelet-derived growth factor (PDGF) signaling. Tumor-associated tissue rigidity resulted in the emergence of stiffness-induced CAFs (siCAFs) in vitro and in vivo. Similar results were confirmed in human data. siCAFs were able to strongly inhibit CD8+ T-cell responses in vitro and in vivo, promoting local immunosuppression. More importantly, targeting PDGF signaling led to diminished siCAF and reduced tumor growth. Our data show for the first time that early paracrine signaling leads to profound changes in tissue mechanics, impacting immune responses and tumor progression. Our study highlights that PDGF ligand neutralization can normalize the tissue architecture independent of the genetic background, indicating that finely tuned stromal therapy may open new therapeutic avenues in pancreatic cancer.

Sclerotome-derived PDGF signaling functions as a niche cue responsible for primitive erythropoiesis.

Primitive erythropoiesis serves a vital role in embryonic development, generating primitive red blood cells responsible for transportation of oxygen throughout the body. Although diverse niche factors are known to function in definitive hematopoiesis, the microenvironment contributing to primitive hematopoiesis remains largely elusive. Here, we report that platelet-derived growth factor (PDGF) signaling is required for erythroid progenitor differentiation in zebrafish. Ablating pdgfαa (also known as pdgfaa) and pdgfαb (also known as pdgfab) or blocking PDGF signaling with an inhibitor impairs erythroid progenitor differentiation, thus resulting in a significant decrease in the number of erythrocytes. We reveal that pdgfαb is expressed in sclerotomal cells, and that its receptor genes, pdgfra and pdgfrb, are expressed in the adjacent erythroid progenitor cells. Sclerotome-specific overexpression of pdgfαb effectively restores primitive erythropoiesis in pdgfαa-/-;pdgfαb-/- mutant embryos. In addition, we have defined ERK1/2 signaling as a downstream pathway of PDGF signaling during embryonic erythropoiesis. Taken together, our findings indicate that PDGF signaling derived from sclerotome functions as a niche cue for primitive erythropoiesis.

Integrating single-cell and spatial transcriptomics to elucidate the crosstalk between cancer-associated fibroblasts and cancer cells in hepatocellular carcinoma with spleen-deficiency syndrome

Background and aimMost patients with hepatocellular carcinoma (HCC) in China have been diagnosed with spleen deficiency syndrome (SDS), which accelerates the progression of HCC by disrupting the tumor microenvironment homeostasis. This study aimed to investigate the intercellular crosstalk in HCC with SDS. Experimental procedureAn HCC-SDS mouse model was established using orthotopic HCC transplantation based on reserpine-induced SDS. Single-cell data analysis and cancer cell prediction were conducted using Seurat and CopyKAT package, respectively. Intercellular interactions were explored using CellPhoneDB and CellChat and subsequently validated using co-culture assays, ELISA and histological staining. We performed pathway activity analysis using gene set variation analysis and the Seurat package. The extracellular matrix (ECM) remodeling was assessed using a gel contraction assay, atomic force microscopy, and Sirius red staining. The deconvolution of the spatial transcriptomics data using the “CARD” package based on single-cell data. Results and conclusionWe successfully established the HCC-SDS mouse model. Twenty-nine clusters were identified. The interactions between cancer cells and cancer-associated fibroblasts (CAFs) were significantly enhanced via platelet-derived growth factor (PDGF) signaling in HCC-SDS. CAFs recruited in HCC-SDS lead to ECM remodeling and the activation of TGF-β signaling pathway. Deconvolution of the spatial transcriptome data revealed that CAFs physically surround cancer cells in HCC-SDS. This study reveals that the crosstalk of CAFs-cancer cells is crucial for the tumor-promoting effect of SDS. CAFs recruited by HCC via PDGFA may lead to ECM remodeling through activation of the TGF-β pathway, thereby forming a physical barrier to block immune cell infiltration under SDS.

Platelet-derived growth factor-stimulated pulmonary artery smooth muscle cells regulate pulmonary artery endothelial cell dysfunction through extracellular vesicle miR-409-5p.

Platelet-derived growth factor (PDGF)-induced changes in vascular smooth muscle cells (VSMCs) stimulate vascular remodeling, resulting in vascular diseases such as pulmonary arterial hypertension. VSMCs communicate with endothelial cells through extracellular vesicles (EVs) carrying cargos, including microRNAs. To understand the molecular mechanisms through which PDGF-stimulated pulmonary artery smooth muscle cells (PASMCs) interact with pulmonary artery endothelial cells (PAECs) under pathological conditions, we investigated the crosstalk between PASMCs and PAECs via extracellular vesicle miR-409-5p under PDGF stimulation. miR-409-5p expression was upregulated in PASMCs upon PDGF signaling, and it was released into EVs. The elevated expression of miR-409-5p was transported to PAECs and led to their impaired function, including reduced NO release, which consequentially resulted in enhanced PASMC proliferation. We propose that the positive regulatory loop of PASMC-extracellular vesicle miR-409-5p-PAEC is a potential mechanism underlying the proliferation of PASMCs under PDGF stimulation. Therefore, miR-409-5p may be a novel therapeutic target for the treatment of vascular diseases, including pulmonary arterial hypertension.

Myocardial Recovery in Recent Onset Dilated Cardiomyopathy: Role of CDCP1 and Cardiac Fibrosis.

Dilated cardiomyopathy (DCM) is a major cause of heart failure and carries a high mortality rate. Myocardial recovery in DCM-related heart failure patients is highly variable, with some patients having little or no response to standard drug therapy. A genome-wide association study may agnostically identify biomarkers and provide novel insight into the biology of myocardial recovery in DCM. A genome-wide association study for change in left ventricular ejection fraction was performed in 686 White subjects with recent-onset DCM who received standard pharmacotherapy. Genome-wide association study signals were subsequently functionally validated and studied in relevant cellular models to understand molecular mechanisms that may have contributed to the change in left ventricular ejection fraction. The genome-wide association study identified a highly suggestive locus that mapped to the 5'-flanking region of the CDCP1 (CUB [complement C1r/C1s, Uegf, and Bmp1] domain containing protein 1) gene (rs6773435; P=7.12×10-7). The variant allele was associated with improved cardiac function and decreased CDCP1 transcription. CDCP1 expression was significantly upregulated in human cardiac fibroblasts (HCFs) in response to the PDGF (platelet-derived growth factor) signaling, and knockdown of CDCP1 significantly repressed HCF proliferation and decreased AKT (protein kinase B) phosphorylation. Transcriptomic profiling after CDCP1 knockdown in HCFs supported the conclusion that CDCP1 regulates HCF proliferation and mitosis. In addition, CDCP1 knockdown in HCFs resulted in significantly decreased expression of soluble ST2 (suppression of tumorigenicity-2), a prognostic biomarker for heart failure and inductor of cardiac fibrosis. CDCP1 may play an important role in myocardial recovery in recent-onset DCM and mediates its effect primarily by attenuating cardiac fibrosis.

Exploring the role of growth factors as potential regulators in psoriatic plaque formation.

Psoriasis is a chronic inflammatory skin disease in which growth activity is more prominent than inflammatory activity at the centre of lesional skin (CE skin). This growth activity is partly influenced by growth factors (GFs) that play an important role in cell growth and inflammation during the plaque development. In this study, we identified potential GFs in CE skin and predicted their regulatory functions and biological activity in mediating transcripts in the plaques. Samples of uninvolved skin (UN skin) and CE skin were biopsied from patients with psoriasis vulgaris for RNA-sequencing analysis in order to identify differentially expressed genes (DEGs). Our finding revealed that epidermal growth factor (EGF), fibroblast growth factor (FGF), platelet-derived growth factor (PDGF) and hepatocyte growth factor (HGF) signalling were enriched by CE/UN skin-derived DEGs. Additionally, several EGFR ligands, namely EGF, heparin-binding EGF like growth factor (HB-EGF), amphiregulin (AREG) and transforming growth factor (TGF)-α, as well as TGF-β1, TGF-β2, vascular endothelial growth factor-A, FGFs, PDGF-B and HGF, were predicted to be GF regulators. The regulatory pattern and biological activity of these GF regulators on mediating the CE/UN skin-derived DEGs was demonstrated. This study provides a novel hypothesis regarding the overall regulatory function of GFs, which appear to modulate the expression of the transcripts involved in inflammation and growth in the CE skin. In addition, some GFs may exert anti-inflammatory effects. Further investigations on the mechanisms underlying this regulation may contribute to a deeper understanding of psoriasis and the identification of potential therapeutic targets for patients with psoriasis.

Systematic analysis of the prognosis and immune infiltration of E2Fs in thyroid carcinoma.

Purpose: To evaluate the diagnostic and prognostic utility of E2F transcription factors (E2Fs) in thyroid carcinoma (THCA) and their association with immune infiltration. Methods: The transcription and protein levels of E2Fs in THCA tissues were examined using the R language and the Human Protein Atlas (HPA) database in this research. We utilized the UALCAN and GEPIA2 databases to analyze the association between the level of E2Fs and the clinicopathological features of THCA. The prognostic utility of E2F expression in THCA was studied using the R language and the Gene Set Cancer Analysis (GSCA) database. Over-representation analysis (ORA) and gene set enrichment analysis (GSEA) were employed to analyze the effect of E2F family members. The TISIDB database and Tumor Immune Estimation Resource (TIMER) database were utilized to investigate the relationship between E2F expression and the level of immune infiltration in thyroid cancer. Results: E2Fs are highly conserved in thyroid carcinoma and rarely mutated. E2Fs are strongly expressed in THCA and are highly related with the clinicopathological stage of THCA. Patients with THCA have a poor prognosis when E2Fs are highly expressed. The function of E2Fs in THCA may be closely related to the renin-angiotensin system (Ras) signaling pathway, platelet-derived growth factor (PDGF) signaling pathway, apoptosis, and immune response. With regard to the immune infiltration, E2F expression and tumor-infiltrating lymphocytes exhibited a positive connection. Conclusion: The level of E2Fs is connected with the prognosis and immune infiltration level in THCA, revealing that E2Fs may be a prognostic and immune infiltration cell marker in THCA patients.

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.

Nigella sativa L. seed extracts promote wound healing progress by activating VEGF and PDGF signaling pathways: An in vitro and in silico study

Background: A significant area of clinical research is the development of natural wound healing products and the management of chronic wounds. Healing wounds with medicinal plants has been a practice of ancient civilizations for centuries. Nigella sativa L (N. sativa) is a medicinal plant that has several pharmacological properties. Methods: The present study evaluated the wound healing properties of Nigella sativa L. (N. sativa) seed extracts using normal cell lines such as normal human dermal fibroblasts (NHDFs) and human umbilical vein endothelial cells (HUVECs). The expression levels of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) were analyzed through western blot analysis. Furthermore, computational analyses were carried out to screen the potential bioactive compounds for wound healing applications. Results: The results of the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay revealed that, all the tested solvent extracts of N. sativa seeds (including ethanol, ethyl acetate, chloroform, and petroleum ether) did not exert any cytotoxic effects at the tested concentrations. Furthermore, the western blot analysis showed elevated levels of VEGF and PDGF upon treatment with N. sativa seed extracts. Gas chromatography-mass spectrometry (GC-MS) analysis of N. sativa extracts identified 268 phytocompounds. Molecular docking studies revealed that three phytocompounds of N. sativa extracts, including tricyclo[20.8.0.0(7,16)]triacontane, 1(22),7(16)-diepoxy-, adaphostin and obeticholic acid had strong binding affinity with wound healing-related target proteins, showing docking scores ranging from -5.5 to -10.9 Kcal/mol. These compounds had acceptable Absorption, Distribution, Metabolism, and Excretion (ADME) properties. Conclusions: Based on these results, N. sativa seed extracts might possess potential wound healing properties owing to the presence of a wide range of bioactive components.

#5531 MOLECULAR IMAGING OF PDGFR-β IN KIDNEY FIBROSIS

Abstract Background and Aims Chronic kidney disease affects &amp;gt;10% of the world's population and is associated with high mortality and morbidity. The best predictor of CKD progression is the extent of fibrosis, i.e., pathological deposition of extracellular matrix (ECM) and loss of functional kidney parenchyme. Currently, there are no specific treatment options and invasive biopsies remain the gold standard for diagnosis. Multiple signaling pathways are involved in fibrosis, including platelet-derived growth factor (PDGF) signaling. Mesenchymal stromal cells express both PDGF receptors PDGFR-α and PDGFR-β, whose activation drives proliferation, migration and production of extracellular matrix, i.e., key processes involved in fibrosis initiation and progression. Based on these notions, we set out to study the bicyclic PDGFR-β-binding peptide (BiPPB) for diagnosis, quantitative imaging and treatment monitoring of kidney fibrosis. Method The biodistribution and kidney accumulation of Cy7-labeled BiPPB and a scrambled peptide control were visualized and quantified using in vivo computed tomography - fluorescence molecular tomography (CT-FMT), ex vivo fluorescence reflectance imaging (FRI) and microscopy. This was done in three different mouse models of kidney fibrosis: the unilateral ischemia-reperfusion injury (I/R), the adenine-induced nephropathy (Adenine) and a transgenic model with constitutive PDGFR-β activation specifically in renal mesenchymal cells leading to increased PDGFR-β expression and expansion of PDGFR-β+ cells (Mutant). In the latter model, we also monitored pharmacological PDGFR-β inhibition with imatinib. Kidney fibrosis and therapeutic efficacy findings were verified by immunohistochemistry (IHC). Results In vivo 3D CT-FMT imaging and ex vivo 2D FRI showed strong accumulation in fibrotic kidneys for Cy7-labeled BiPPB, whereas only moderate amounts accumulated in the contralateral (I/R) and healthy (Adenine) kidney over 48 hours after i.v. injection. The accumulation of the scrambled BiPPB was also significantly lower compared to the specific BiPPB. In transgenic Mutant mice with specific activation of mesenchymal cells and primary renal scaring significantly more Cy7-BiPPB accumulated in the kidneys in comparison to healthy wildtype littermates. In combination with imatinib treatment for three weeks (Mutant imatinib) the accumulation of Cy7-BiPPB was decreased (Fig. 1a-c). This was confirmed ex vivo by significantly increased probe accumulation (2D FRI; Fig. 1d) and PDGFR-β expression (immunohistochemistry (IHC) Fig. 1e) in fibrotic kidneys, which was diminished by imatinib treatment. Conclusion Our findings demonstrate the potential of PDGFR-β-based imaging agents for non-invasive and quantitative monitoring of renal fibrosis progression and therapy response.

Single-cell transcriptomic dissection of the toxic impact of di(2-ethylhexyl) phthalate on immature testicular development at the neonatal stage.

Di(2-ethylhexyl) phthalate (DEHP) early exposure leads to immature testicular injury, and we aimed to utilize single-cell RNA (scRNA) sequencing to comprehensively assess the toxic effect of DEHP on testicular development. Therefore, we gavaged pregnant C57BL/6 mice with 750mg/kg body weight DEHP from gestational day 13.5 to delivery and performed scRNA sequencing of neonatal testes at postnatal day 5.5. The results revealed the gene expression dynamics in testicular cells. DEHP disrupted the developmental trajectory of germ cells and the balance between the self-renewal and differentiation of spermatogonial stem cells. Additionally, DEHP caused an abnormal developmental trajectory, cytoskeletal damage and cell cycle arrest in Sertoli cells; disrupted the metabolism of testosterone in Leydig cells; and disturbed the developmental trajectory in peritubular myoid cells. Elevated oxidative stress and excessive apoptosis mediated by p53 were observed in almost all testicular cells. The intercellular interactions among four cell types were altered, and biological processes related to glial cell line-derived neurotrophic factor (GDNF), transforming growth factor-β (TGF-β), NOTCH, platelet-derived growth factor (PDGF) and WNT signaling pathways were enriched after DEHP treatment. These findings systematically describe the damaging effects of DEHP on the immature testes and provide substantial novel insights into the reproductive toxicity of DEHP.

Nigella sativa L. seed extracts promote wound healing progress by activating VEGF and PDGF signaling pathways: An in vitro and in silico study.

Background: A significant area of clinical research is the development of natural wound healing products and the management of chronic wounds. Healing wounds with medicinal plants has been a practice of ancient civilizations for centuries. Nigella sativa L ( N. sativa) is a medicinal plant that has several pharmacological properties. Methods: The present study evaluated the wound healing properties of Nigella sativa L. ( N. sativa) seed extracts using normal cell lines such as normal human dermal fibroblasts (NHDFs) and human umbilical vein endothelial cells (HUVECs). The expression levels of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) were analyzed through western blot analysis. Furthermore, computational analyses were carried out to screen the potential bioactive compounds for wound healing applications. Results: The results of the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay revealed that, all the tested solvent extracts of N. sativa seeds (including ethanol, ethyl acetate, chloroform, and petroleum ether) did not exert any cytotoxic effects at the tested concentrations. Furthermore, the western blot analysis showed elevated levels of VEGF and PDGF upon treatment with N. sativa seed extracts. Gas chromatography-mass spectrometry (GC-MS) analysis of N. sativa extracts identified 268 phytocompounds. Molecular docking studies revealed that three phytocompounds of N. sativa extracts, including tricyclo[20.8.0.0(7,16)]triacontane, 1(22),7(16)-diepoxy-, adaphostin and obeticholic acid had strong binding affinity with wound healing-related target proteins, showing docking scores ranging from -5.5 to -10.9 Kcal/mol. These compounds had acceptable Absorption, Distribution, Metabolism, and Excretion (ADME) properties. Conclusions: Based on these results, N. sativa seed extracts might possess potential wound healing properties owing to the presence of a wide range of bioactive components.

Topical application of imatinib mesylate ameliorated psoriasis-like skin lesions in imiquimod-induced murine model via angiogenesis inhibition.

Psoriasis is a chronic skin disorder characterized by a skin rash with scaly patches. Microvascular abnormalities are a characteristic feature of psoriasis and play a crucial role in the pathogenesis of psoriatic lesions. Angiogenic factors are upregulated in psoriatic skin lesions and are thought to induce angiogenesis. Platelet-derived growth factor (PDGF) induces vascular endothelial growth factor (VEGF), and PDGF is upregulated in keratinocytes in psoriatic skin lesions. The present study aimed to investigate the effect of topical imatinib mesylate (IMT) in inhibiting the activation of PDGF signalling in the pathogenesis of psoriasis. When topically applied to the skin of mice with imiquimod (IMQ)-induced psoriasis, IMT ameliorated skin symptoms similar to those of human psoriasis. Hyperproliferation of keratinocytes, hyperkeratosis, inflammatory cell infiltration and hypervascularity were histologically suppressed by topical IMT. The expression of angiogenic factors including fibroblast growth factor (FGF) and VEGF was decreased. The expression of FGF and VEGF in a PDGF-stimulated fibroblast cell line was inhibited by IMT. PDGF is required for the signalling pathway producing angiogenic factors in fibroblast. Thus, topically applied IMT inhibits PDGFR activation in fibroblast and suppresses the production of angiogenic factors, thereby mitigating the symptoms of psoriasis. The inhibitory effect of IMT on angiogenesis suggests that topical application IMT may be a viable treatment option for psoriasis.

The number of primitive endoderm cells in the inner cell mass is regulated by platelet-derived growth factor signaling in porcine preimplantation embryos.

Discovering the mechanism of cell specification is important to manipulate cellular lineages. To obtain lineage-specific cell lines, the target lineage needs to be promoted, and counterpart lineages should be suppressed. Embryos in the early blastocyst stage possess two different cell populations, the inner cell mass (ICM) and trophectoderm. Then, cells in the ICM segregate into epiblasts (Epi) and primitive endoderm (PrE). PrE cells in embryos show specific expression of platelet-derived growth factor (PDGF) and its receptor, PDGF receptor A (PDGFRA). In this study, we suppressed PDGF signaling using two methods (CRISPR/Cas9 injection and inhibitor treatment) to provide insight into the segregation of embryonic lineages. CRISPR/Cas9 RNAs were injected into parthenogenetically activated and in vitro fertilized embryos. The PDGF receptor inhibitor AG1296 was treated at 0, 5, 10, and 20 μM concentration. The developmental competence of the embryos and the number of cells expressing marker proteins (SOX2 for ICM and SOX17 for PrE) were measured after the treatments. The expression levels of the marker genes with the inhibitor were examined during embryo development. Microinjection targeting the PDGF receptor (PDGFR) A reduced the number of SOX17-positive cell populations in a subset of day 7 blastocysts (n = 9/12). However, microinjection accompanied diminution of Epi cells in the blastocyst. The PDGF receptor inhibitor AG1296 (5 μM) suppressed SOX17-positive cells without reducing SOX2-positive cells in both parthenogenetic activated and in vitro fertilized embryos. Within the transcriptional target of PDGF signaling, the inhibitor significantly upregulated the Txnip gene in embryos. We identified that PDGF signaling is important to sustain the PrE population in porcine blastocysts. Additionally, treatment with inhibitors was a better method to suppress PrE cells than CRISPR/Cas9 microinjection of anti-PDGF receptor α gene, because microinjection suppressed number of Epi cells. The PDGF receptor might control the number of PrE cells by repressing the proapoptotic gene Txnip. Our results can help to isolate Epi-specific cell lines from blastocysts.

PDGF gene expression and p53 alterations contribute to the biology of diffuse astrocytic gliomas

Diffuse, histologically lower grade astrocytomas of adults (LGAs) are classified based on the mutational status of the isocitrate dehydrogenase (IDH) genes. While wild-type (WT) LGAs often evolve quickly to glioblastoma (GBM), mutant tumors typically follow an indolent course. To find possible effectors of these different behaviors, we compared their respective transcriptomes. Unlike mutant LGAs, platelet-derived growth factor (PDGF) signaling was significantly enriched in WT tumors, and PDGFA was the top overexpressed gene in the pathway. Moreover, methylation of the PDGFA and PDGFD promoters emerged as a possible mechanism for their low expression in mutant tumors. Copy number gain of chromosome 7 co-occurred with high expression of PDGFA in WT cases, and high expression of PDGFA was associated with aneuploidy, extracellular matrix (ECM)-related immunosuppressive features and poor prognosis. We also noted that high PDGFA expression in WT cases occurred irrespective of tumor grade and that multiple mechanisms of p53 pathway inactivation accompanied progression to GBM in PDGFA-overexpressing tumors. Conversely, TP53 point mutations were an early and constant feature of mutant LGAs. Our results suggest that members of the PDGF gene family, in concert with different p53 pathway alterations, underlie LGA behaviors.