Effects of electroacupuncture on the microvascular structure and related protein expression in the hippocampus of vascular dementia rats. / ç”µé’ˆå¯¹è¡€ç®¡æ€§ç—´å‘†å¤§é¼ æµ·é©¬å¾®è¡€ç®¡ç»“æž„å’Œç›¸å ³è›‹ç™½è¡¨è¾¾çš„å½±å“.

OBJECTIVES: To explore the effect of electroacupuncture (EA) at "Baihui" (GV20) and "Shenting" (GV24) on the microvascular structure and related protein expression in the hippocampus of vascular dementia (VD) rat model, and to investigate the mechanism of EA in the treatment of VD. METHODS: A total of 24 SD rats were randomly divided into sham operation, model, EA, and oxiracetam groups, with 6 rats in each group. Multiple cerebral infarction method was used to establish VD model. In the EA group, EA was applied to GV20 and GV24 for 30 min, once daily for 14 days. Rats in the oxiracetam group were treated with oxiracetam (50 mg/kg) by intraperitoneal injection, and the course of treatment was the same as that in the EA group. Learning and memory ability were evaluated by using Morris water maze test and new object recognition experiment. The cerebral blood flow was detected by laser doppler. The microvascular structure in the hippocampus was observed by transmission electron microscopy. The expression of vascular structure related proteins of platelet-derived growth factor receptor (PDGFR)-ß, platelet endothelial cell adhesion molecule-1(CD31), neural cadherin N-Cadherin, Zonula occludens protein-1(ZO-1) in the hippocampus were measured by Western blot. RESULTS: Compared with the sham operation group, the rats in the model group had a significant increase in time of first crossing the platform, a significant decrease in the number of crossing platform and the new object preference index (P<0.05), a significant decrease in cerebral blood flow (P<0.05), and a significant increase in the brain weight (P<0.05). The structure boundary of pericyte and endothelial cells in the microvessels of the hippocampal CA1 area of model group was blurred, accompanied by obvious edema around the vessels and the reduction of tight junctions. The protein expression levels of PDGFR-ß, CD31, N-Cadherin, ZO-1 were significantly decreased in the model group compared with those in the sham operation group (P<0.05). Compared with the model group, the time of first crossing the platform of rats in the EA and oxiracetam group was shortened, the number of crossing platform were increased (P<0.05), the cerebral blood flow was increased (P<0.05), the brain weight was decreased (P<0.05), the morphology and structure of pericyte and endothelial cells in the microvessels of hippocampal CA1 area were intact, accompanied by the increase of tight junctions. Additionally, Compared with the model group, the EA group had a significant increase in the new object preference index (P<0.05), the protein expression levels of PDGFR-ß, CD31, ZO-1 in the EA group were increased (P<0.05), and the expression of PDGFR-ß, N-Cadherin, ZO-1 in the oxiracetam group were increased (P<0.05). CONCLUSIONS: EA at GV20 and GV24 can improve the learning and memory ability of VD rats, and the mechanism may be related to the repair of microvascular structures and improvement of cerebral blood flow.

A Soluble Platelet-Derived Growth Factor Receptor-ß Originates via Pre-mRNA Splicing in the Healthy Brain and Is Upregulated during Hypoxia and Aging.

The platelet-derived growth factor-BB (PDGF-BB) pathway provides critical regulation of cerebrovascular pericytes, orchestrating their investment and retention within the brain microcirculation. Dysregulated PDGF Receptor-beta (PDGFRß) signaling can lead to pericyte defects that compromise blood-brain barrier (BBB) integrity and cerebral perfusion, impairing neuronal activity and viability, which fuels cognitive and memory deficits. Receptor tyrosine kinases such as PDGF-BB and vascular endothelial growth factor-A (VEGF-A) are often modulated by soluble isoforms of cognate receptors that establish signaling activity within a physiological range. Soluble PDGFRß (sPDGFRß) isoforms have been reported to form by enzymatic cleavage from cerebrovascular mural cells, and pericytes in particular, largely under pathological conditions. However, pre-mRNA alternative splicing has not been widely explored as a possible mechanism for generating sPDGFRß variants, and specifically during tissue homeostasis. Here, we found sPDGFRß protein in the murine brain and other tissues under normal, physiological conditions. Utilizing brain samples for follow-on analysis, we identified mRNA sequences corresponding to sPDGFRß isoforms, which facilitated construction of predicted protein structures and related amino acid sequences. Human cell lines yielded comparable sequences and protein model predictions. Retention of ligand binding capacity was confirmed for sPDGFRß by co-immunoprecipitation. Visualizing fluorescently labeled sPDGFRß transcripts revealed a spatial distribution corresponding to murine brain pericytes alongside cerebrovascular endothelium. Soluble PDGFRß protein was detected throughout the brain parenchyma in distinct regions, such as along the lateral ventricles, with signals also found more broadly adjacent to cerebral microvessels consistent with pericyte labeling. To better understand how sPDGFRß variants might be regulated, we found elevated transcript and protein levels in the murine brain with age, and acute hypoxia increased sPDGFRß variant transcripts in a cell-based model of intact vessels. Our findings indicate that soluble isoforms of PDGFRß likely arise from pre-mRNA alternative splicing, in addition to enzymatic cleavage mechanisms, and these variants exist under normal physiological conditions. Follow-on studies will be needed to establish potential roles for sPDGFRß in regulating PDGF-BB signaling to maintain pericyte quiescence, BBB integrity, and cerebral perfusion-critical processes underlying neuronal health and function, and in turn, memory and cognition.

Analysis of stromal PDGFR-ß and α-SMA expression and their clinical relevance in brain metastases of breast cancer patients.

BACKGROUND: Breast cancer brain metastasis (BCBM) is a growing therapeutic challenge and clinical concern. Stromal cancer-associated fibroblasts (CAFs) are crucial factors in the modulation of tumorigeneses and metastases. Herein, we investigated the relationship between the expression of stromal CAF markers in metastatic sites, platelet-derived growth factor receptor-beta (PDGFR-ß), and alpha-smooth muscle actin (α-SMA) and the clinical and prognostic variables in BCBM patients. METHODS: Immunohistochemistry (IHC) of the stromal expression of PDGFR-ß and α-SMA was performed on 50 cases of surgically resected BCBM. The expression of the CAF markers was analyzed in the context of clinico-pathological characteristics. RESULTS: Expression of PDGFR-ß and α-SMA was lower in the triple-negative (TN) subtype than in other molecular subtypes (p = 0.073 and p = 0.016, respectively). And their expressions were related to a specific pattern of CAF distribution (PDGFR-ß, p = 0.009; α-SMA, p = 0.043) and BM solidity (p = 0.009 and p = 0.002, respectively). High PDGFR-ß expression was significantly related to longer recurrence-free survival (RFS) (p = 0.011). TN molecular subtype and PDGFR-ß expression were independent prognostic factors of recurrence-free survival (p = 0.029 and p = 0.030, respectively) and TN molecular subtype was an independent prognostic factor of overall survival (p < 0.001). CONCLUSIONS: Expression of PDGFR-ß in the stroma of BM was associated with RFS in BCBM patients, and the clinical implication was uniquely linked to the low expression of PDGFR-ß and α-SMA in the aggressive form of the TN subtype.

Decreased functional connectivity is associated with increased levels of Cerebral Spinal Fluid soluble-PDGFRß, a marker of blood brain barrier breakdown, in older adults.

Resting-state functional connectivity (FC) is suggested to be cross-sectionally associated with both vascular burden and Alzheimer's disease (AD) pathology. For instance, studies in pre-clinical AD subjects have shown increases of cerebral spinal fluid soluble platelet-derived growth factor receptor-ß (CSF sPDGFRß, a marker of BBB breakdown) but have not demonstrated if this vascular impairment affects neuronal dysfunction. It's possible that increased levels of sPDGFRß in the CSF may correlate with impaired FC in metabolically demanding brain regions (i.e. Default Mode Network, DMN). Our study aimed to investigate the relationship between these two markers in older individuals that were cognitively normal and had cognitive impairment. Eighty-nine older adults without dementia from the University of Southern California were selected from a larger cohort. Region of interest (ROI) to ROI analyses were conducted using DMN seed regions. Linear regression models measured significant associations between BOLD FC strength among seed-target regions and sPDGFRß values, while covarying for age and sex. Comparison of a composite ROI created by averaging FC values between seed and all target regions among cognitively normal and impaired individuals was also examined. Using CSF sPDGFRß as a biomarker of BBB breakdown, we report that increased breakdown correlated with decreased functional connectivity in DMN areas, specifically the PCC while the hippocampus exhibited an interaction effect using CDR score. We conclude that BBB breakdown as measured by CSF sPDGFRß affects neural networks resulting in decreased functional connections that leads to cognitive dysfunction.

Interplay of Low-Density Lipoprotein Receptors, LRPs, and Lipoproteins in Pulmonary Hypertension.

The low-density lipoprotein receptor (LDLR) gene family includes LDLR, very LDLR, and LDL receptor-related proteins (LRPs) such as LRP1, LRP1b (aka LRP-DIT), LRP2 (aka megalin), LRP4, and LRP5/6, and LRP8 (aka ApoER2). LDLR family members constitute a class of closely related multifunctional, transmembrane receptors, with diverse functions, from embryonic development to cancer, lipid metabolism, and cardiovascular homeostasis. While LDLR family members have been studied extensively in the systemic circulation in the context of atherosclerosis, their roles in pulmonary arterial hypertension (PAH) are understudied and largely unknown. Endothelial dysfunction, tissue infiltration of monocytes, and proliferation of pulmonary artery smooth muscle cells are hallmarks of PAH, leading to vascular remodeling, obliteration, increased pulmonary vascular resistance, heart failure, and death. LDLR family members are entangled with the aforementioned detrimental processes by controlling many pathways that are dysregulated in PAH; these include lipid metabolism and oxidation, but also platelet-derived growth factor, transforming growth factor ß1, Wnt, apolipoprotein E, bone morpohogenetic proteins, and peroxisome proliferator-activated receptor gamma. In this paper, we discuss the current knowledge on LDLR family members in PAH. We also review mechanisms and drugs discovered in biological contexts and diseases other than PAH that are likely very relevant in the hypertensive pulmonary vasculature and the future care of patients with PAH or other chronic, progressive, debilitating cardiovascular diseases.

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

BACKGROUND: Cerebrospinal fluid (CSF) platelet-derived growth factor receptor-ß (PDGFRß) has been proposed as a biomarker of blood-brain barrier (BBB) breakdown. We studied PDGFRß levels as a biomarker for cerebral amyloid angiopathy (CAA), amnestic mild cognitive impairment (aMCI), or Alzheimer's disease (AD). METHODS: CSF PDGFRß 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 PDGFRß both by clinical phenotype and by using the AT(N) biomarker classification system defined by CSF amyloid (A), tau (T), and neurodegeneration (N) biomarkers. RESULTS: PDGFRß 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 PDGFRß levels compared to (A-T-[N-]) controls (P = .006). CONCLUSION: Our findings indicate that PDGFRß levels are associated with an AD+ biomarker profile but are not a suitable biomarker for CAA or aMCI/AD clinical syndrome.

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

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-ß (PDGFR-ß) 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-ß. The dual-luciferase reporter gene was predicted and applied to detect the target-binding effect of miRNA-9 and PDGFR-ß 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-ß 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-ß 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 3'UTR region of PDGFR-ß, thereby inhibiting the gene expression.

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-ß (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.

BACKGROUND AND AIM: 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-ß (PDGFR-ß) as a magnetic resonance imaging (MRI) radiotracer to identify the progression of liver fibrosis by imaging hepatic PDGFR-ß expression. METHODS: Mice treated with carbon tetrachloride (CCl4 ) were used to mimic hepatic fibrosis in vivo. The binding activity of FITC-labeled pPB to PDGFR-ß was assessed in cultured human HSCs (HSC-LX2). MRI was performed to visualize hepatic PDGFR-ß expression in mice with different degrees of liver fibrosis after Gd-labeled pPB was injected. RESULTS: Hepatic PDGFR-ß expression level was correlated with the severity of liver fibrosis, and the majority of cells expressing PDGFR-ß were found to be activated HSCs in fibrotic livers. Culture-activated human HSCs expressed abundant PDGFR-ß, 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. CONCLUSIONS: Hepatic PDGFR-ß 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.

Blockade of Platelet-Derived Growth Factor Signaling Inhibits Choroidal Neovascularization and Subretinal Fibrosis in Mice.

Neovascular age related macular degeneration (nAMD) leads to severe vision loss worldwide and is characterized by the formation of choroidal neovascularization (CNV) and fibrosis. In the current study, we aimed to investigate the effect of blockade for platelet derived growth factor receptor-ß (PDGFR-ß) on the formation of choroidal neovascularization and fibrosis in the laser-induced CNV model in mice. Firstly, the presence of PDGFR-ß in CNV lesions were confirmed. Intravitreal injection of PDGFR-ß neutralizing antibody significantly reduced the size of CNV and subretinal fibrosis. Additionally, subretinal hyperreflective material (SHRM), a landmark feature on OCT as a risk factor for subretinal fibrosis formation in nAMD patients was also suppressed by PDGFR-ß blockade. Furthermore, pericytes were abundantly recruited to the CNV lesions during CNV formation, however, blockade of PDGFR-ß significantly reduced pericyte recruitment. In addition, PDGF-BB stimulation increased the migration of the rat retinal pericyte cell line, R-rPCT1, which was abrogated by the neutralization of PDGFR-ß. These results indicate that blockade of PDGFR-ß attenuates laser-induced CNV and fibrosis through the inhibition of pericyte migration.

Hypoxia promotes osteosarcoma cell proliferation and migration through enhancing platelet-derived growth factor-BB/platelet-derived growth factor receptor-ß axis.

Osteosarcoma is a primary malignant bone tumor, characterized by high therapeutic resistance and poor outcomes, due to unclear pathological mechanisms. It has been shown recently that the platelet-derived growth factor (PDGF)/platelet-derived growth factor receptor (PDGFR) pathway is closely associated with the pathogenesis of osteosarcoma. Hypoxia is a critical hallmark of tumor microenvironment that promotes the malignant phenotype in many solid tumors and a fundamental impediment to effective tumor therapy. In this study, we confirmed that hypoxia is an important feature of osteosarcoma, validated by the positive immunohistochemistry staining of hypoxia marker hypoxia-inducible factor-1α (HIF-1α) and carbonic anhydrase IX (CAIX) in osteosarcoma tissue samples. More importantly, we discovered that hypoxia could transcriptionally upregulate the expression of both PDGF-BB and PDGFR-ß in osteosarcoma cells in vitro. Likewise, we also established that hypoxia-induced PDGF-BB is strongly related to the enhanced cell proliferation and migration, by activating AKT, ERK1/2, and STAT3 signaling pathways. Notably, when using an antibody to block the autocrine of PDGF-BB, cell proliferation and migration were partially aborted in hypoxia. Collectively, we demonstrated that the hypoxia-activated PDGF-BB/PDGFR-ß axis plays essential roles in osteosarcoma progression. These findings may shed light on the molecular pathogenesis of osteosarcoma, and provide a novel strategy for osteosarcoma treatment by combinational targeting hypoxia and PDGF-BB/PDGFR signaling.

PDGFR-ß modulates vascular smooth muscle cell phenotype via IRF-9/SIRT-1/NF-κB pathway in subarachnoid hemorrhage rats.

Platelet-derived growth factor receptor-ß (PDGFR-ß) has been reported to promote phenotypic transformation of vascular smooth muscle cells (VSMCs). The purpose of this study was to investigate the role of the PDGFR-ß/IRF9/SIRT-1/NF-κB pathway in VSMC phenotypic transformation after subarachnoid hemorrhage (SAH). SAH was induced using the endovascular perforation model in Sprague-Dawley rats. PDGFR-ß small interfering RNA (siRNA) and IRF9 siRNA were injected intracerebroventricularly 48 h before SAH. SIRT1 activator (resveratrol) and inhibitor (EX527) were administered intraperitoneally 1 h after SAH induction. Twenty-four hours after SAH, the VSMC contractile phenotype marker α-smooth muscle actin (α-SMA) decreased, whereas the VSMC synthetic phenotype marker embryonic smooth muscle myosin heavy chain (Smemb) increased. Both PDGFR-ß siRNA and IRF9 siRNA attenuated the induction of nuclear factor-κB (NF-κB) and enhanced the expression of α-SMA. The SIRT1 activator (resveratrol) preserved VSMC contractile phenotype, significantly alleviated neurological dysfunction, and reduced brain edema. However, these beneficial effects of PDGFR-ß siRNA, IRF9 siRNA and resveratrol were abolished by the SIRT1 inhibitor (EX527). This study shows that PDGFR-ß/IRF9/SIRT-1/NF-κB signaling played a role in the VSMC phenotypic transformation after SAH. Inhibition of this signaling cascade preserved the contractile phenotype of VSMCs, thereby improving neurological outcomes following SAH.

Silencing platelet-derived growth factor receptor-ß enhances the radiosensitivity of C6 glioma cells in vitro and in vivo.

Platelet-derived growth factor receptor (PDGFR)-ß is an important tyrosine kinase and its downregulation has been reported to alter the radiosensitivity of glioma cells, although the underlying mechanism is unclear. In order to investigate the effect of PDGFR-ß on the radiosensitivity of glioblastoma, the present study transfected C6 glioma cells with a PDGFR-ß-specific small interfering (si)RNA expression plasmid, and downregulation of the expression of PDGFR-ß in C6 glioma cells was confirmed by western blotting and immunohistochemical analysis. Clone formation assays and xenograft growth curves demonstrated that PDGFR-ß-siRNA enhanced the radiosensitivity of C6 glioma cells in vitro and in vivo. Furthermore, MTT and xenograft growth curves demonstrated that PDGFR-ß-siRNA inhibited the proliferation of C6 glioma cells in vitro and in vivo, and terminal deoxynucleotidyl transferase dUTP nick end-labeling and immunohistochemical analyses demonstrated that PDGFR-ß-siRNA induced apoptosis and inhibited the expression of Ki-67, cyclin B1 and vascular endothelial growth factor in C6 glioma cell xenografts. Taken together, these results suggested that PDGFR-ß may be used as a target for the radiosensitization of glioblastoma.

Differences in Dural Penetration of Clival Chordomas Are Associated with Different Prognosis and Expression of Platelet-Derived Growth Factor Receptor-ß.

OBJECTIVE: We sought to compare the prognosis of clival chordomas with different dural penetration and establish the relationship between dural penetration and platelet-derived growth factor receptor (PDGFR)-ß signaling pathway. METHODS: Tumors in Type I (33 cases) showed limited dural penetration, while those in Type II (34 cases) had more serious dural penetration. Cox multivariate regression analysis was used to analyze risk factors affecting survival. Kaplan-Meier analysis measured overall survival (OS) and progression-free survival (PFS). To determine the relationship between dural penetration and PDGFR-ß signaling, expression of PDGFR-ß, Akt, mammalian target of rapamycin (mTOR), and phosphatase and tensin homolog (PTEN) expression was compared using immunohistochemistry, quantitative reverse transcription polymerase chain reaction, and Western blotting. RESULTS: Total resection was achieved in 9 cases in Type I and 11 in Type II. There were significant correlations between OS and dural penetration (P = 0.032) and age (P = 0.034). PFS correlated significantly with dural penetration (P = 0.022), gender (P = 0.001), and degree of resection (P = 0.001). Mean OS in Type I was significantly longer than in Type II (P = 0.046). Patients aged <55 years had longer OS than those aged ≥55 years (P = 0.004). Total resection was correlated with longer PFS (P = 0.011). Among patients with tumors totally resected, mean PFS in Type I was significantly longer than in Type II (P = 0.007). Expression of PDGFR-ß in Type II was higher than in Type I. CONCLUSIONS: Clival chordomas have different degrees of dural penetration. Patients with chordomas with serious dural penetration have poorer prognosis. Higher expression of PDGFR-ß is related to more serious dural penetration of clival chordomas.

Shedding of soluble platelet-derived growth factor receptor-ß from human brain pericytes.

Platelet-derived growth factor receptor-ß (PDGFRß) is expressed in the brain by vascular mural cells-brain capillary pericytes and arterial vascular smooth muscle cells (VSMCs). Recent evidence shows that blood-brain barrier (BBB) disruption and increased permeability, especially in the hippocampus, positively correlates with elevated levels of soluble PDGFRß (sPDGFRß) in cerebrospinal fluid (CSF) in patients with mild dementia. To determine which vascular cell type(s) contributes to increased sPDGFRß in CSF, we compared PDGFRß expression and sPDGFRß shedding in response to injury in early passage primary cultures of human brain pericytes, brain arterial VSMCs, and brain endothelial cells. PDGFRß protein was undetectable in endothelial cells, but was found both in pericytes and VSMCs. PDGFRß relative protein abundance was by 4.2-fold (p<0.05) higher in pericytes compared to VSMCs. Hypoxia (1% O2) or amyloid-ß peptide (25 µM) compared to normoxia (21% O2) both increased over 48 h shedding of sPDGFRß and its levels in the culture medium from pericytes cultures, but not from VSMCs cultures, by 4.3-fold and 4.6-fold, respectively, compared to the basal sPDGFRß levels in the medium (1.43±0.15 ng/ml). This was associated with the corresponding loss of cell-associated PDGFRß from pericytes and no change in cellular levels of PDGFRß in VSMCs. Thus, sPDGFRß is a biomarker of pericyte injury, and elevated sPDGFRß levels in biofluids in patients with dementia and/or other neurodegenerative disorders likely reflects pericyte injury, which supports the potential for sPDGFRß to be developed and validated as a biomarker of brain pericyte injury and BBB dysfunction.

Changes in glomerular parietal epithelial cells in mouse kidneys with advanced age.

Kidney aging is accompanied by characteristic changes in the glomerulus, but little is known about the effect of aging on glomerular parietal epithelial cells (PECs), nor if the characteristic glomerular changes in humans and rats also occur in very old mice. Accordingly, a descriptive analysis was undertaken in 27-mo-old C57B6 mice, considered advanced age. PEC density was significantly lower in older mice compared with young mice (aged 3 mo), and the decrease was more pronounced in juxtamedullary glomeruli compared with outer cortical glomeruli. In addition to segmental and global glomerulosclerosis in older mice, staining for matrix proteins collagen type IV and heparan sulfate proteoglycan were markedly increased in Bowman's capsules of older mouse glomeruli, consistent with increased extracellular matrix production by PECs. De novo staining for CD44, a marker of activated and profibrotic PECs, was significantly increased in aged glomeruli. CD44 staining was more pronounced in the juxtamedullary region and colocalized with phosphorylated ERK. Additionally, a subset of aged PECs de novo expressed the epithelial-to-mesenchymal transition markers α-smooth muscle and vimentin, with no changes in epithelial-to-mesenchymal transition markers E-cadherin and ß-catenin. The mural cell markers neural/glial antigen 2, PDGF receptor-ß, and CD146 as well as Notch 3 were also substantially increased in aged PECs. These data show that mice can be used to better understand the aging kidney and that PECs undergo substantial changes, especially in juxtamedullary glomeruli, that may participate in the overall decline in glomerular structure and function with advancing age.

Hypoxia-induced changes in protein s-nitrosylation in female mouse brainstem.

Exposure to hypoxia elicits an increase in minute ventilation that diminishes during continued exposure (roll-off). Brainstem N-methyl-D-aspartate receptors (NMDARs) and neuronal nitric oxide synthase (nNOS) contribute to the initial hypoxia-induced increases in minute ventilation. Roll-off is regulated by platelet-derived growth factor receptor-ß (PDGFR-ß) and S-nitrosoglutathione (GSNO) reductase (GSNOR). S-nitrosylation inhibits activities of NMDAR and nNOS, but enhances GSNOR activity. The importance of S-nitrosylation in the hypoxic ventilatory response is unknown. This study confirms that ventilatory roll-off is virtually absent in female GSNOR(+/-) and GSNO(-/-) mice, and evaluated the location of GSNOR in female mouse brainstem, and temporal changes in GSNOR activity, protein expression, and S-nitrosylation status of GSNOR, NMDAR (1, 2A, 2B), nNOS, and PDGFR-ß during hypoxic challenge. GSNOR-positive neurons were present throughout the brainstem, including the nucleus tractus solitarius. Protein abundances for GSNOR, nNOS, all NMDAR subunits and PDGFR-ß were not altered by hypoxia. GSNOR activity and S-nitrosylation status temporally increased with hypoxia. In addition, nNOS S-nitrosylation increased with 3 and 15 minutes of hypoxia. Changes in NMDAR S-nitrosylation were detected in NMDAR 2B at 15 minutes of hypoxia. No hypoxia-induced changes in PDGFR-ß S-nitrosylation were detected. However, PDGFR-ß phosphorylation increased in the brainstems of wild-type mice during hypoxic exposure (consistent with roll-off), whereas it did not rise in GSNOR(+/-) mice (consistent with lack of roll-off). These data suggest that: (1) S-nitrosylation events regulate hypoxic ventilatory response; (2) increases in S-nitrosylation of NMDAR 2B, nNOS, and GSNOR may contribute to ventilatory roll-off; and (3) GSNOR regulates PDGFR-ß phosphorylation.

Nanomedicine therapeutic approaches to overcome cancer drug resistance.

Nanomedicine is an emerging form of therapy that focuses on alternative drug delivery and improvement of the treatment efficacy while reducing detrimental side effects to normal tissues. Cancer drug resistance is a complicated process that involves multiple mechanisms. Here we discuss the major forms of drug resistance and the new possibilities that nanomedicines offer to overcome these treatment obstacles. Novel nanomedicines that have a high ability for flexible, fast drug design and production based on tumor genetic profiles can be created making drug selection for personal patient treatment much more intensive and effective. This review aims to demonstrate the advantage of the young medical science field, nanomedicine, for overcoming cancer drug resistance. With the advanced design and alternative mechanisms of drug delivery known for different nanodrugs including liposomes, polymer conjugates, micelles, dendrimers, carbon-based, and metallic nanoparticles, overcoming various forms of multi-drug resistance looks promising and opens new horizons for cancer treatment.

Clinicopathological significance of platelet-derived growth factor B, platelet-derived growth factor receptor-ß, and E-cadherin expression in gastric carcinoma.

AIM OF THE STUDY: Platelet-derived growth factor B (PDGF-B), a vital growth factor which can induce angiogenesis and epithelial-mesenchymal transition (EMT), is important in the metastasis of many tumors. However, the roles of PDGF-B in gastric carcinoma are largely unknown. We investigated the correlation between PDGF-B, PDGFR-ß and E-cadherin expression with the clinical features of gastric carcinoma patients to evaluate the relationship between PDGF-B signaling, E-cadherin and metastasis of gastric carcinoma, the correlation between PDGF-B and E-cadherin expression to assess the roles of PDGF-B signaling in metastasis of gastric carcinoma.. MATERIAL AND METHODS: We detected expressions of PDGF-B, PDGFR-ß and E-cadherin in gastric carcinoma tissues and normal gastric mucosa tissues of 64 patients with gastric carcinoma who had undergone surgical resection, and investigated their relationships with clinical features and the relationships between PDGF-B and E-cadherin expression in gastric carcinoma. RESULTS: In surgical specimens, tumor cells expressed PDGF-B, and PDGFR-ß was expressed by tumor stromal cells. E-cadherin was expressed by both tumor cells and normal gastric mucosa cells. Expressions of PDGF-B and PDGFR-ß were increased in gastric carcinoma tissues (p < 0.05) and were positively correlated with the depth of cancer invasion, lymph node metastasis and TNM stage (p < 0.05). The expression of E-cadherin was reduced in gastric carcinoma tissues (p < 0.05) and was negatively correlated with the depth of cancer invasion, lymph node metastasis and TNM stage (p < 0.05). The correlation between PDGF-B and E-cadherin expression was negative (p < 0.05). CONCLUSION: Our data indicate that either the overexpression of PDGF-B and PDGFR-ß or the underexpression of E-cadherin is correlated with cancer progression and lymphogenous metastasis of gastric carcinoma. The PDGF-B signal pathway might induce EMT by down-regulating expression of E-cadherin to promote metastasis of gastric carcinoma.