Platelet-derived Growth Factor Receptor-β Research Articles

Prolyl-4-hydroxylases 2 and 3 control erythropoietin production in renin-expressing cells of mouse kidneys.

Activation of the hypoxia-signalling pathway induced by deletion of the ubiquitin-ligase von Hippel-Lindau protein causes an endocrine shift of renin-producing cells to erythropoietin (EPO)-expressing cells. However, the underlying mechanisms have not yet been investigated. Since oxygen-regulated stability of hypoxia-inducible transcription factors relevant for EPO expression is dependent on the activity of prolyl-4-hydroxylases (PHD) 2 and 3, this study aimed to determine the relevance of different PHD isoforms for the EPO expression in renin-producing cells in vivo. For this purpose, mice with inducible renin cell-specific deletions of different PHD isoforms were analysed. Our study shows that there are two subgroups of renal renin-expressing cells, juxtaglomerular renin+ cells and platelet-derived growth factor receptor-β+ interstitial renin+ cells. These interstitial renin+ cells belong to the cell pool of native EPO-producing cells and are able to express EPO and renin in parallel. In contrast, co-deletion of PHD2 and PHD3, but not PHD2 deletion alone, induces EPO expression in juxtaglomerular and hyperplastic renin+ cells and downregulates renin expression. A strong basal PHD3 expression in juxtaglomerular renin+ cells seems to prevent the hypoxia-inducible transcription factor-2-dependent phenotype shift into EPO cells. In summary, PHDs seem important for the stabilization of the juxtaglomerular renin cell phenotype. Moreover, these findings reveal tubulointerstitial cells as a novel site of renal renin expression and suggest a high endocrine plasticity of these cells. Our data concerning the distinct expression patterns and functions of PHD2 and PHD3 provide new insights into the regulation of renin-producing cells and highlight the need for selective PHD inhibitors. KEY POINTS: Renal renin-expressing cells can be clearly distinguished into two subgroups, the typical juxtaglomerular renin-producing cells and interstitial renin+ cells. Interstitial renin+ cells belong to the cell pool of native erythropoietin (EPO)-producing cells, show a fast EPO response to acute hypoxia-inducible factor-2 (HIF-2) stabilization and are able to express EPO and renin in parallel. Only co-deletion of the prolyl-4-hydroxylases (PHD) 2 and 3, but not PHD2 deletion alone, induces EPO expression in juxtaglomerular renin+ cells. Chronic HIF-2 stabilization in juxtaglomerular renin-expressing cells leads to their phenotypic shift into EPO-producing cells. A strong basal PHD3 expression in juxtaglomerular renin+ cells seems to prevent a HIF-2-dependent phenotype shift into EPO cells suggesting PHD3 fulfils a stabilizer function for the juxtaglomerular renin cell phenotype.

Serum platelet-derived growth factor-BB levels as a potential biomarker in assessing the metabolic activity of lesions in alveolar echinococcosis patients

BackgroundAlveolar echinococcosis (AE) is a chronic disease caused by the larval stage of Echinococcus multilocularis. Assessing the metabolic activity of AE lesions is critical to evaluate disease progression and survey treatment options. There is an urgent need to identify more rapid, convenient, and non-invasive clinical detection methods to substitute the current techniques. Herein, we evaluated the viability of platelet-derived growth factor-BB (PDGF-BB) as a biomarker for detecting the metabolic activity of AE patients and their correlations with clinicopathological features of AE patients. MethodsSera were collected from 28 AE patients and a homogenous cohort of 28 healthy individuals. The concentration of serum PDGF-BB homodimers (sPDGF-BB) was assessed via an enzyme-linked immunosorbent assay (ELISA). Liver tissue samples were obtained from a consecutive series of 28 AE patients who underwent surgical resection. Thereafter, we determined the expression levels of local PDGF-BB and platelet-derived growth factor receptor-β (PDGFR-β) through immunohistochemistry (IHC). Correlations of PDGF-BB expression levels with clinicopathological features of AE patients were analyzed using SPSS. ResultsThe concentrations of sPDGF-BB were significantly lower in AE patients (p < 0.0001), particularly in High Metabolically Active AE patients (HMAE) patients (p < 0.05). The expression levels of PDGF-BB and its receptor were both significantly higher in close liver tissue (CLT) in AE patients (p < 0.0001). We also found that metabolically active AE and sPDGF-BB are significantly negatively correlated (r = -0.624, p = 0.0004). Beside, the local expression levels of PDGF-BB was positively correlated with metabolic activity, PNM stage, and lesion size. Notably, the sPDGF-BB levels were proposed as a potential biomarker for assessing metabolic activity of AE, with 81.0% sensitivity and 85.7% specificity (95% confidence interval, p = 0.003). ConclusionsSerum levels of PDGF-BB could be a simple, non-invasive, and quick biomarker for assessing the metabolic activity of lesions in AE patients.

Correlation between mechanism of oxidized-low density lipoprotein-induced macrophage apoptosis and inhibition of target gene platelet derived growth factor receptor-β expression by microRNA-9

ABSTRACT This study was to explore the effects of oxidized-low density lipoprotein (ox-LDL) on the proliferation and apoptosis of macrophages, and the role of miRNA-9 in the targeted regulation of platelet-derived growth factor receptor-β (PDGFR-β) expression. Macrophage RAW264.7 cells were cultured and foamed with 100 mg/L ox-LDL to detect the cell proliferation and apoptosis and target protein expression levels. Subsequently, the miRNA-9 mimics and inhibitors were transfected to detect the expression level of PDGFR-β. The dual-luciferase reporter gene was predicted and applied to detect the target-binding effect of miRNA-9 and PDGFR-β in the cells. The results showed that ox-LDL could induce the foaming of macrophages RAW264.7, inhibit the cell proliferation, and promote the cell apoptosis. After ox-LDL induction, expression of Caspase-3 in macrophages RAW264.7 was up-regulated, and that of glucose regulated protein 78 was down-regulated. The transfection of miRNA-9 mimics could greatly inhibit the expression of PDGFR-β mRNA and proteins in the cells. In addition, the results of the dual-luciferase reporter gene showed that the ratio of luciferase activity was significantly reduced after the miRNA-9 mimic and the wild-type PDGFR-β plasmid were co-transfected. In summary, ox-LDL could induce foaming of macrophages and promote cell apoptosis, and miRNA-9 could target and bind to the 3ʹUTR region of PDGFR-β, thereby inhibiting the gene expression.

Normal cerebrospinal fluid concentrations of PDGFRβ in patients with cerebral amyloid angiopathy and Alzheimer's disease.

Cerebrospinal fluid (CSF) platelet-derived growth factor receptor-β (PDGFRβ) has been proposed as a biomarker of blood-brain barrier (BBB) breakdown. We studied PDGFRβ levels as a biomarker for cerebral amyloid angiopathy (CAA), amnestic mild cognitive impairment (aMCI), or Alzheimer's disease (AD). CSF PDGFRβ levels were quantified by enzyme-linked immunosorbent assay in patients with CAA, patients with aMCI/AD, and in matched controls. In aMCI/AD we evaluated CSF PDGFRβ both by clinical phenotype and by using the AT(N) biomarker classification system defined by CSF amyloid (A), tau (T), and neurodegeneration (N) biomarkers. PDGFRβ levels were similar in CAA patients and controls (P=.78) and in aMCI/AD clinical phenotype and controls (P=.91). aMCI/AD patients with an AD+ biomarker profile (A+T+[N+]) had increased PDGFRβ levels compared to (A-T-[N-]) controls (P=.006). Our findings indicate that PDGFRβ levels are associated with an AD+ biomarker profile but are not a suitable biomarker for CAA or aMCI/AD clinical syndrome.

Retinal vascular abnormalities and blood-retinal barrier breakdown in Alzheimer's disease.

Vascular changes including cerebral amyloid angiopathy (CAA), reduced blood flow, pericyte loss and vascular platelet-derived growth factor receptor-β (PDGFRβ) deficiency have emerged as prominent features of Alzheimer's disease (AD). We previously identified the existence of the pathological hallmarks of AD, amyloid β-protein (Aβ) plaques, along with intracellular and vascular Aβ deposits in the neurosensory retina of AD patients. Data suggest that certain retinal signs manifest early in disease progression and appear similar to those observed in the brain. Yet, retinal vascular abnormalities in AD and their ability to predict cerebral pathology and cognitive decline are poorly understood. Here, we assessed vascular changes including capillary degeneration, PDGFRβ expression, vascular amyloidosis, pericyte loss, and blood-retinal barrier (BRB) permeability in postmortem retinas from a cohort of mild cognitively impaired (MCI) and AD patients. We evaluated retinal cross-sections from pre-defined topographical regions and isolated retinal vascular networks labeled by periodic acid-Schiff or immunofluorescence. We further quantified capillary degeneration, PDGFRβ expression, vascular amyloidosis, and inner BRB tight-junction molecule expression and BRB leakage in transgenic APPSWE /PS1ΔE9 mouse models of AD (ADtg mice) at different disease stages. Early and progressive PDGFRβ deficiency and pericyte loss were found in retinas from AD patients. PDGFRβ deficiency associated with vascular Aβ deposits in postmortem retinas from a cohort of MCI and AD patients. In ADtg mice as compared to age- and sex-matched wild-type mice, we found significant degeneration of retinal capillaries (P<0.0001). ADtg retinas also displayed a substantial vascular PDGFRβ deficiency (∼50% reduction, P=0.0017) and vascular Aβ deposition, which inversely correlated with the extent of degenerated capillaries (Pearson's r=-0.8, P=0.0016). Tight-junction alterations including claudin-1 downregulation and increased BRB permeability were found in ADtg mice. In postmortem retinas from the human cohort, retinal PDGFRβ loss significantly associated with increased retinal vascular Aβ40 and Aβ42 burdens. Decreased vascular LRP-1 and early apoptosis of pericytes in AD retina were further revealed. Correlations were identified between retinal vascular abnormalities and cerebral Aβ burden, CAA, and clinical status. Overall, the identification of age- and Alzheimer's-dependent retinal capillary degeneration and compromised BRB integrity starting at early disease stages provide novel targets for AD diagnosis and therapy.

Increased expression of epimorphin in a peritoneal fibrosis mouse model

Long-term peritoneal dialysis results in functional and histopathological alterations of the peritoneal membrane, leading to peritoneal fibrosis (PF). The mechanism of PF has not been fully elucidated, and at present there is no effective therapy for PF. Epimorphin is a mesenchymal protein that not only regulates morphogenesis in organ development but is implicated in tissue repair. However, the role of epimorphin in PF has not yet been clarified. PF was induced in C57/Bl6 mice by intraperitoneal injection of chlorhexidine gluconate (CG-injected mice) three times a week for 3 weeks. The parietal peritoneum was subsequently dissected and assessed by Masson's trichrome staining, and epimorphin expression was analysed by immunohistochemistry and real-time reverse transcription polymerase chain reaction (RT-PCR). Furthermore, epimorphin-positive regions were analysed by multiple immunofluorescence staining using fibrosis-associated markers. In addition, normal rat fibroblast cells (NRK-49F) were treated with transforming growth factor-β (TGF-β) in the presence or absence of epimorphin. The expression of fibrosis-associated markers was assessed by real-time RT-PCR. In CG-injected mice, Masson's trichrome staining showed marked thickening of the submesothelial compact zone. Weak epimorphin expression was observed in the narrow submesothelial compact zone beneath the mesothelial cells in control mice; however, epimorphin expression was stronger in the submesothelial compact zone in CG-injected mice. Epimorphin expression was observed mainly in α-smooth muscle actin (α-SMA)-positive myofibroblasts. Epimorphin suppressed the TGF-β-induced upregulation of α-SMA and platelet-derived growth factor receptor-β in cultured cells. Our results suggest that epimorphin may be a therapeutic target for fibrotic diseases of the peritoneum.

Retinal Vasculopathy in Alzheimer's Disease.

The retina has been increasingly investigated as a site of Alzheimer’s disease (AD) manifestation for over a decade. Early reports documented degeneration of retinal ganglion cells and their axonal projections. Our group provided the first evidence of the key pathological hallmarks of AD, amyloid β-protein (Aβ) plaques including vascular Aβ deposits, in the retina of AD and mild cognitively impaired (MCI) patients. Subsequent studies validated these findings and further identified electroretinography and vision deficits, retinal (p)tau and inflammation, intracellular Aβ accumulation, and retinal ganglion cell-subtype degeneration surrounding Aβ plaques in these patients. Our data suggest that the brain and retina follow a similar trajectory during AD progression, probably due to their common embryonic origin and anatomical proximity. However, the retina is the only CNS organ feasible for direct, repeated, and non-invasive ophthalmic examination with ultra-high spatial resolution and sensitivity. Neurovascular unit integrity is key to maintaining normal CNS function and cerebral vascular abnormalities are increasingly recognized as early and pivotal factors driving cognitive impairment in AD. Likewise, retinal vascular abnormalities such as changes in vessel density and fractal dimensions, blood flow, foveal avascular zone, curvature tortuosity, and arteriole-to-venule ratio were described in AD patients including early-stage cases. A rapidly growing number of reports have suggested that cerebral and retinal vasculopathy are tightly associated with cognitive deficits in AD patients and animal models. Importantly, we recently identified early and progressive deficiency in retinal vascular platelet-derived growth factor receptor-β (PDGFRβ) expression and pericyte loss that were associated with retinal vascular amyloidosis and cerebral amyloid angiopathy in MCI and AD patients. Other studies utilizing optical coherence tomography (OCT), retinal amyloid-fluorescence imaging and retinal hyperspectral imaging have made significant progress in visualizing and quantifying AD pathology through the retina. With new advances in OCT angiography, OCT leakage, scanning laser microscopy, fluorescein angiography and adaptive optics imaging, future studies focusing on retinal vascular AD pathologies could transform non-invasive pre-clinical AD diagnosis and monitoring.

Cardiac microvascular functions improved by MSC-derived exosomes attenuate cardiac fibrosis after ischemia–reperfusion via PDGFR-β modulation

Microvascular dysfunction caused by cardiac ischemia–reperfusion (I/R) leads to multiple severe cardiac adverse events, such as heart failure and ventricular modeling, which plays a critical role in outcomes. Though marrow mesenchymal stem cell (MSC) therapy has been proven effective for attenuating I/R injury, the limitations of clinical feasibility cannot be ignored. Since exosomes are recognized as the main vehicles for MSCs paracrine effects, we assumed that MSC-derived exosomes could prevent microvascular dysfunction and further protect cardiac function. By establishing a rat cardiac I/R model in vivo and a cardiac microvascular endothelial cells (CMECs) hypoxia–reperfusion (H/R) model in vitro, we demonstrated that MSC-derived exosomes enhanced microvascular regeneration under stress, inhibited fibrosis development, and eventually improved cardiac function through platelet-derived growth factor receptor-β (PDGFR-β) modulation. Furthermore, we found that MSC-derived exosomes possessed better therapeutic effects than MSCs themselves.

Pathological Role of Phosphoglycerate Kinase 1 in Balloon Angioplasty-Induced Neointima Formation

Restenosis is a common vascular complication after balloon angioplasty. Catheter balloon inflation-induced transient ischemia (hypoxia) of local arterial tissues plays a pathological role in neointima formation. Phosphoglycerate kinase 1 (PGK1), an adenosine triphosphate (ATP)-generating glycolytic enzyme, has been reported to associate with cell survival and can be triggered under hypoxia. The purposes of this study were to investigate the possible role and regulation of PGK1 in vascular smooth muscle cells (VSMCs) and balloon-injured arteries under hypoxia. Neointimal hyperplasia was induced by a rat carotid artery injury model. The cellular functions and regulatory mechanisms of PGK1 in VSMCs were investigated using small interfering RNAs (siRNAs), chemical inhibitors, or anaerobic cultivation. Our data indicated that protein expression of PGK1 can be rapidly induced at a very early stage after balloon angioplasty, and the silencing PGK1-induced low cellular energy circumstance resulted in the suppressions of VSMC proliferation and migration. Moreover, the experimental results demonstrated that blockage of PDGF receptor-β (PDGFRB) or its downstream pathway, the phosphoinositide 3-kinase (PI3K)-AKT-mammalian target of rapamycin (mTOR) axis, effectively reduced hypoxia-induced factor-1 (HIF-1α) and PGK1 expressions in VSMCs. In vivo study evidenced that PGK1 knockdown significantly reduced neointima hyperplasia. PGK1 was expressed at the early stage of neointimal formation, and suppressing PGK1 has a potential beneficial effect for preventing restenosis.

A magnetic resonance imaging modality for non-invasively distinguishing progression of liver fibrosis by visualizing hepatic platelet-derived growth factor receptor-beta expression in mice.

Activated hepatic stellate cells (HSCs) are the most critical cells responsible for liver fibrosis, and platelet-derived growth factor (PDGF) is the most prominent mitogen for HSCs in fibrogenesis. This study aimed to explore the potential of gadolinium (Gd)-labeled cyclic peptides (pPB) targeting PDGF receptor-β (PDGFR-β) as a magnetic resonance imaging (MRI) radiotracer to identify the progression of liver fibrosis by imaging hepatic PDGFR-β expression. Mice treated with carbon tetrachloride (CCl4 ) were used to mimic hepatic fibrosis in vivo. The binding activity of FITC-labeled pPB to PDGFR-β was assessed in cultured human HSCs (HSC-LX2). MRI was performed to visualize hepatic PDGFR-β expression in mice with different degrees of liver fibrosis after Gd-labeled pPB was injected. Hepatic PDGFR-β expression level was correlated with the severity of liver fibrosis, and the majority of cells expressing PDGFR-β were found to be activated HSCs in fibrotic livers. Culture-activated human HSCs expressed abundant PDGFR-β, and FITC-labeled pPB could bind to these cells in a concentration-dependent and time-dependent manner. With Gd-labeled pPB as a tracer, an MRI modality demonstrated that the relative hepatic T1-weighted MRI signal value progressively increased with the severity of hepatic fibrosis and reduced with remission. Hepatic PDGFR-β expression reflects the progression of hepatic fibrosis, and MRI using Gd-labeled pPB as a tracer exhibits potential for distinguishing liver fibrosis staging in mice.

Preventive Effect and Mechanism of Crossostephium chinense Extract on Balloon Angioplasty-Induced Neointimal Hyperplasia.

Balloon angioplasty-induced neointimal hyperplasia remains a clinical problem that must be resolved. The bioactivities of the Crossostephium chinense extract (CCE) have demonstrated potential in preventing the progression of restenosis. The present study evaluated whether CCE can suppress balloon angioplasty-induced neointima formation and elucidated its possible pharmacological mechanisms. A rat model of carotid arterial balloon angioplasty was established to evaluate the inhibitory effect of CCEs on neointimal hyperplasia. Two cell lines, A10 vascular smooth muscle cells (VSMCs) and RAW264.7 macrophages, were used to investigate the potential regulatory activities and pharmacological mechanisms of CCEs in cell proliferation and migration and in inflammation. Our in vitro results indicated that CCE3, the ethanolic extract of C. chinense, exerted the strongest growth inhibitory and antimigratory effects on VSMCs. CCE3 blocked the activation of focal adhesion kinase, platelet-derived growth factor receptor-β (PDGFRB), and its downstream molecules (AKT and mTOR) and reduced the expression of matrix metalloproteinase-2. In addition, our findings revealed that CCE3 significantly increased the expression of miRNA-132, an inhibitory regulator of inflammation and restenosis, and suppressed the expression of inflammation-related molecules (inducible nitric oxide synthase, cyclooxygenase-2, interleukin- (IL-) 1β, and IL-6). Our in vivo study results indicated that balloon injury-induced neointimal hyperplasia was inhibited by CCE3. CCE3 could reduce neointima formation in balloon-injured arteries, and this effect may be partially attributed to the CCE3-induced suppression of PDGFRB-mediated downstream pathways and inflammation-related molecules.

Gold Nanoparticles Affect Pericyte Biology and Capillary Tube Formation.

Gold nanoparticles (AuNPs) are used for diagnostic and therapeutic purposes, especially antiangiogenesis, which are accomplished via inhibition of endothelial cell proliferation, migration, and tube formation. However, no research has been performed on the effects of AuNPs in pericytes, which play vital roles in endothelial cell functions and capillary tube formation during physiological and pathological processes. Therefore, the effects of AuNPs on the morphology and functions of pericytes need to be elucidated. This study treated human placental pericytes in monoculture with 20 nm AuNPs at a concentration of 30 ppm. Ki-67 and platelet-derived growth factor receptor-β (PDGFR-β) mRNA expression was measured using real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell migration was assessed by Transwell migration assay. The fine structures of pericytes were observed by transmission electron microscopy. In addition, 30 ppm AuNP-treated pericytes and intact human umbilical vein endothelial cells were cocultured on Matrigel to form three-dimensional (3D) capillary tubes. The results demonstrated that AuNPs significantly inhibited proliferation, reduced PDGFR-β mRNA expression, and decreased migration in pericytes. Ultrastructural analysis of pericytes revealed AuNPs in late endosomes, autolysosomes, and mitochondria. Remarkably, many mitochondria were swollen or damaged. Additionally, capillary tube formation was reduced. We found that numerous pericytes on 3D capillary tubes were round and did not extend their processes along the tubes, which resulted in more incomplete tube formation in the treatment group compared with the control group. In summary, AuNPs can affect pericyte proliferation, PDGFR-β mRNA expression, migration, morphology, and capillary tube formation. The findings highlight the possible application of AuNPs in pericyte-targeted therapy for antiangiogenesis.

Temporal dynamics of cells expressing NG2 and platelet-derived growth factor receptor-β in the fibrotic scar formation after 3-nitropropionic acid-induced acute brain injury.

Neuron-glia antigen 2 (NG2) proteoglycan and platelet-derived growth factor receptor beta (PDGFR-β) are widely used markers of pericytes, which are considered cells that form fibrotic scars in response to central nervous system insults. However, the exact phenotypes of NG2- and PDGFR-β-expressing cells, as well as the origin of the fibrotic scar after central nervous system insults, are still elusive. In the present study, we directly examined the identities and distributions of NG2- and PDGFR-β-positive cells in the control and lesioned striatum injured by the mitochondrial toxin 3-nitropropionic acid. Immunoelectron microscopy and correlative light and electron microscopy clearly distinguished NG2 and PDGFR-β expression in the vasculature during the post-injury period. Vascular smooth muscle cells and pericytes expressed NG2, which was prominently increased after the injury. NG2 expression was restricted to these vascular mural cells until 14days post-lesion. By contrast, PDGFR-β-positive cells were perivascular fibroblasts located abluminal to smooth muscle cells or pericytes. These PDGFR-β-expressing cells formed extravascular networks associated with collagen fibrils at 14days post-lesion. We also found that in the injured striatal parenchyma, PDGFR-β could be used as a complementary marker of resting and reactive NG2 glia because activated microglia/macrophages shared only the NG2 expression with NG2 glia in the lesioned striatum. These data indicate that NG2 and PDGFR-β label different vascular mural and parenchymal cells in the healthy and injured brain, suggesting that fibrotic scar-forming cells most likely originate in PDGFR-β-positive perivascular fibroblasts rather than in NG2-positive pericytes.

Improved Recovery from Liver Fibrosis by Crenolanib.

Chronic liver diseases are associated with excessive deposition of extracellular matrix proteins. This so-called fibrosis can progress to cirrhosis and impair vital functions of the liver. We examined whether the receptor tyrosine kinase (RTK) class III inhibitor Crenolanib affects the behavior of hepatic stellate cells (HSC) involved in fibrogenesis. Rats were treated with thioacetamide (TAA) for 18 weeks to trigger fibrosis. After TAA treatment, the animals received Crenolanib for two weeks, which significantly improved recovery from liver fibrosis. Because Crenolanib predominantly inhibits the RTK platelet-derived growth factor receptor-β, impaired HSC proliferation might be responsible for this beneficial effect. Interestingly, blocking of RTK signaling by Crenolanib not only hindered HSC proliferation but also triggered their specification into hepatic endoderm. Endodermal specification was mediated by p38 mitogen-activated kinase (p38 MAPK) and c-Jun-activated kinase (JNK) signaling; however, this process remained incomplete, and the HSC accumulated lipids. JNK activation was induced by stress response-associated inositol-requiring enzyme-1α (IRE1α) in response to Crenolanib treatment, whereas β-catenin-dependent WNT signaling was able to counteract this process. In conclusion, the Crenolanib-mediated inhibition of RTK impeded HSC proliferation and triggered stress responses, initiating developmental processes in HSC that might have contributed to improved recovery from liver fibrosis in TAA-treated rats.

Traditional Chinese Medicine Shenmayizhi Decoction Ameliorates Memory and Cognitive Impairment Induced by Multiple Cerebral Infarctions.

This study aimed to illustrate the mechanism by which Shenmayizhi decoction (SMYZD) improves the learning memory of rats with vascular cognitive impairment (VCI). Fifty male and female Wistar rats of specific pathogen-free grade (SPF grade) were used to establish the model by the administration of a microsphere embolization. This was accomplished by injecting sterile, standardized, mass-produced microspheres of uniform particle size (100–200 µm in diameter) in a sodium alginate microsphere vascular embolic agent suspension to induce VCI. The VCI model was successfully established in 40 rats, including both male and female rats, and the rats were randomly divided into 4 groups of 10 rats each. The model group was administered an equal volume of distilled water. The donepezil group was administered 0.45 mg/kg/d donepezil, which is equivalent to the clinical dosage. The SMYZ-H group was administered 11.88 g/kg/d SMYZ, which is 4 times higher than the clinically equivalent dosage. The SMYZ-L group was administered 2.97 g/kg/d SMYZ, which is the clinically equivalent dosage. A sham-operated group was used as the control group and administered an equal volume of distilled water. The rats in the 4 groups were treated by gavage with equal volumes of liquid and the indicated concentration of drug diluted in distilled water for 8 consecutive weeks. Two months later, the Morris water maze (MWM) was used to evaluate the spatial memory of all the rats. Ultrastructural and ultrapathological changes in the capillaries of the cerebral cortex were observed by transmission electron microscopy. Furthermore, Western blot and RT-PCR analyses were used to assess the levels of platelet-derived growth factor receptor-β (PDGFR-β), neuron-glial antigen 2 (NG2), vascular endothelial growth factor A (VEGF-A), and angiopoietin 1 (Ang1) in the cerebral cortex of the rats. The results showed that SMYZD at concentrations of 11.88 g/kg/d and 2.97 g/kg/d (SMYZ-H and SMYZ-L) significantly shortened the escape latency (EL). In addition, SMYZ-H significantly prolonged the distance traveled and the time spent in the original platform quadrant by the rats with VCI. SMYZ-H significantly increased the NG2 and Ang1 protein expression levels and increased the PDGFR-β and Ang1 mRNA levels. These results demonstrated that Shenmayizhi decoction can improve the memory abilities of rats with VCI induced by multiple cerebral infarctions by preventing pericyte degeneration.

Morphology/Interstitial Fluid Pressure-Tunable Nanopomegranate Designed by Alteration of Membrane Fluidity under Tumor Enzyme and PEGylation.

Up to now, insufficient drug accumulation in tumor remains a major challenge for nanochemotherapy. However, the spherical nanocarriers with large diameter, which are beneficial for blood circulation and tumor extravasation, cannot travel deep in a tumor. Additionally, high tumor interstitial fluid pressure (IFP) in the tumor microenvironment may promote the efflux of the penetrable nanodrugs. Therefore, the size and shape of nanocarriers as well as the tumoral IFP can be regulated synchronously for improved tumor penetration and combined chemotherapy. Herein, a novel dual-functional polymer-polypeptide (Biotin-PEG2000-GKGPRQITITK) for both verified tumor targeting and responsiveness was synthesized to construct the "peel" of nanopomegranate-like nanovectors (DI-MPL), in which docetaxel-loaded micelles was encapsulated as "seeds". Interestingly, DI-MPL was endowed multi-abilities of tunable size/shape switch and controlled release of IFP alleviator imatinib (IM), which were developed with one and the same strategy-alteration of membrane fluidity under the cleavage of polymer-polypeptide and PEGylation. As a result, the peel of DI-MPL could turn into small pieces with the seed scattered out in response to matrix metalloproteinase-9 (MMP-9), making nanopomegranate (180 nm) switch into spheres/disks (40 nm), during which IM is released to reduce IFP synchronously. With prominent tumor penetration ability in both multicellular tumor spheroids (MCTS) and tumor tissue, DI-MPL exhibited optimal inhibition of MCTS growth and the enhanced chemotherapy in comparison to other preparations. Meanwhile, the improved penetrability of DI-MPL in tumor tissue was found to be related to the reduced IFP, which is achieved via inhibiting expression of phosphorylated platelet-derived growth factor receptor-β (p-PDGFR-β) by IM. Altogether, the bilateral adjusting strategies from nanocarrier size/shape and tumoral IFP with a single enzyme-responsive material could provide a potential combined chemotherapy to improve tumor penetration.

Systemic infection exacerbates cerebrovascular dysfunction in Alzheimer's disease.

We studied the effects of systemic infection on brain cytokine level and cerebral vascular function in Alzheimer's disease and vascular dementia, in superior temporal cortex (Brodmann area 22) from Alzheimer's disease patients (n = 75), vascular dementia patients (n = 22) and age-matched control subjects (n = 46), stratified according to the presence or absence of terminal systemic infection. Brain cytokine levels were measured using Mesoscale Discovery Multiplex Assays and markers of cerebrovascular function were assessed by ELISA. Multiple brain cytokines were elevated in Alzheimer's disease and vascular dementia: IL-15 and IL-17A were maximally elevated in end-stage Alzheimer's disease (Braak tangle stage V-VI) whereas IL-2, IL-5, IL12p40 and IL-16 were highest in intermediate Braak tangle stage III-IV disease. Several cytokines (IL-1β, IL-6, TNF-α, IL-8 and IL-15) were further raised in Alzheimer's disease with systemic infection. Cerebral hypoperfusion-indicated by decreased MAG:PLP1 and increased vascular endothelial growth factor-A (VEGF)-and blood-brain barrier leakiness, indicated by raised levels of fibrinogen, were exacerbated in Alzheimer's disease and vascular dementia patients, and also in non-dementia controls, with systemic infection. Amyloid-β42 level did not vary with infection or in association with brain cytokine levels. In controls, cortical perfusion declined with increasing IFN-γ, IL-2, IL-4, IL-6, IL-10, IL-12p70, IL-13 and tumour necrosis factor-α (TNF-α) but these relationships were lost with progression of Alzheimer's disease, and with infection (even in Braak stage 0-II brains). Cortical platelet-derived growth factor receptor-β (PDGFRβ), a pericyte marker, was reduced, and endothelin-1 (EDN1) level was increased in Alzheimer's disease; these were related to amyloid-β level and disease progression and only modestly affected by systemic infection. Our findings indicate that systemic infection alters brain cytokine levels and exacerbates cerebral hypoperfusion and blood-brain barrier leakiness associated with Alzheimer's disease and vascular dementia, independently of the level of insoluble amyloid-β, and highlight systemic infection as an important contributor to dementia, requiring early identification and treatment in the elderly population.

Inhibition of transforming growth factor β1 signaling in resident interstitial cells attenuates profibrotic gene expression and preserves erythropoietin production during experimental kidney fibrosis in mice

Kidney fibrosis is characterized by the development of myofibroblasts originating from resident kidney and immigrating cells. Myofibroblast formation and extracellular matrix production during kidney damage are triggered by various cytokines. Among these, transforming growth factor β1 (TGFβ1) is considered a central trigger for kidney fibrosis. We found a highly upregulated expression of TGFβ1 and TGFβ receptor 2 (TGFβ-R2) mRNAs in kidney interstitial cells in experimental fibrosis. Here, we investigated the contribution of TGFβ1 signaling in resident kidney interstitial cells to organ fibrosis using the models of adenine induced nephropathy and unilateral ureteral occlusion in mice. For this purpose TGFβ1 signaling was interrupted by inducible deletion of the TGFβ-R2 gene in interstitial cells expressing the fibroblast marker platelet derived growth factor receptor-β. Expression of profibrotic genes was attenuated up to 50% in kidneys lacking TGFβ-R2 in cells positive for platelet derived growth factor receptor-β. Additionally, deletion of TGFβ-R2 prevented the decline of erythropoietin production in ureter ligated kidneys. Notably, fibrosis associated expression of α-smooth muscle actin as a myofibroblast marker and deposits of extracellular collagens were not altered in mice with targeted deletion of TGFβ-R2. Thus, our findings suggest an enhancing effect of TGFβ1 signaling in resident interstitial cells that contributes to profibrotic gene expression and the downregulation of erythropoietin production, but not to the development of myofibroblasts during kidney fibrosis.

Prognostic and Therapeutic Utility of Variably Expressed Cell Surface Receptors in Osteosarcoma

Background Six cell surface receptors, human epidermal growth factor receptor-2 (Her-2), platelet-derived growth factor receptor-β (PDGFR-β), insulin-like growth factor-1 receptor (IGF-1R), insulin receptor (IR), c-Met, and vascular endothelial growth factor receptor-3 (VEGFR-3), previously demonstrated variable expression across varying patient-derived and standard osteosarcoma (OS) cell lines. The current study sought to validate previous expression patterns and evaluate whether these receptors offer prognostic and/or therapeutic value. Methods Patient-derived OS cell lines (n = 52) were labeled with antibodies to Her-2, PDGFR-β, IGF-1R, IR, c-Met, and VEGFR-3. Expression was characterized using flow cytometry. The difference in geometric mean fluorescent intensity (geoMFIdiff = geoMFIpositive − geoMFInegative) was calculated for each receptor across all cell lines. Receptor expression was categorized as low (Q1), intermediate (Q2, Q3), or high (Q4). The event-free survival (EFS) and overall survival for the six cell surface receptors were estimated by the Kaplan–Meier method. Differences in hazard for EFS event and overall survival event for patients in each of the three expression levels in each of the six cell surface receptors were assessed using the log-rank test. Results All 6 receptors were variably expressed in the majority of cell lines. IR and PDGFR-β expressions were found to be significant predictors for EFS amongst patients with nonmetastatic disease (p=0.02 and 0.01, respectively). The hazard ratio for EFS was significantly higher between high IR and intermediate IR expression (HR = 2.66, p=0.02), as well as between high PDGFR-β and intermediate PDGFR-β expression (HR = 5.68, p=0.002). Her-2, c-Met, IGF-1R, and VEGFR-3 were not found to be significant predictors for either EFS or overall survival. Conclusion The six cell surface receptors demonstrated variable expression across the majority of patient-derived OS cell lines tested. Limited prognostic value was offered by IR and PDGFR-β expression within nonmetastatic patients. The remaining receptors do not provide clear prognostic utility. Nevertheless, their consistent, albeit variable, surface expression across a large panel of patient-derived OS cell lines maintains their potential use as future therapeutic targets.

Reactive sulfur species inhibit the migration of PDGF-treated vascular smooth muscle cells by blocking the reactive oxygen species-regulated Akt signaling pathway

Vascular smooth muscle cell (VSMC) migration contributes to vascular remodeling after injury, whereas oxidative stress generated through dysfunctional redox homeostasis induces hypermigration, leading to arteriosclerosis. Platelet-derived growth factor (PDGF)-induced reactive oxygen species (ROS) serve as intracellular signaling molecules in VSMCs. Reactive sulfur species (RSS) may serve as a biological defense system because of the antioxidative properties of highly nucleophilic sulfane sulfur. However, insufficient information is available on its function in PDGF-induced VSMC migration. Here we show that PDGF significantly increased the levels of intracellular sulfane sulfur and that intracellular sulfane sulfur donors, donor 5a and Na2S4, inhibited the increase in ROS levels in PDGF-treated VSMCs and inhibited their migration. Consistent with the migration results, sulfane sulfur donors inhibited Akt phosphorylation, a downstream signaling molecule in the PDGF cascade, without affecting the autophosphorylation of PDGF receptor-β. Further, sulfane sulfur donors inhibited vinculin and paxillin recruitment to the leading edge of VSMCs in response to PDGF to decrease focal adhesion formation. These findings suggest that RSS are required for PDGF-stimulated VSMC migration through the regulation of the ROS-regulated Akt pathway, which may contribute to focal adhesion formation. Our findings provide insight into RSS as novel regulators of vascular redox homeostasis.