scholarly journals Lysophosphatidic acid suppresses endothelial cell CD36 expression and promotes angiogenesis via a PKD-1–dependent signaling pathway

Blood ◽  
2011 ◽  
Vol 117 (22) ◽  
pp. 6036-6045 ◽  
Author(s):  
Bin Ren ◽  
James Hale ◽  
Sowmya Srikanthan ◽  
Roy L. Silverstein

Abstract In pathologic settings including retinal ischemia and malignant tumors, robust angiogenesis occurs despite the presence in the microenvironment of antiangiogenic proteins containing thrombospondin structural homology (TSR) domains. We hypothesized that antiangiogenesis mediated by TSR-containing proteins could be blunted by localized down-regulation of their cognate receptor on microvascular endothelial cells (MVECs), CD36. Through screening a panel of endothelial cell agonists, we found that lysophosphatidic acid (LPA) dramatically down-regulated CD36 surface expression on primary MVECs. LPA is a lipid-signaling mediator known to have proangiogenic activity, but the mechanisms are largely unknown. We observed that LPA caused CD36 down-regulation in a dose- and time-dependent manner and was long lasting. Down-regulation occurred at the transcriptional level via a signaling pathway involving specific LPA receptors and protein kinase D. LPA-induced MVEC CD36 repression significantly attenuated in vitro antiangiogenic responses to thrombospondin-1, including blockade of migration, tube formation, and VEGFR-2 signaling in response to fibroblast growth factor-2. In vivo relevance was demonstrated by showing that LPA abrogated thrombospondin-1–mediated inhibition of neovascularization of Matrigel plugs implanted in mice. Our data thus indicate that the proangiogenic mechanism of LPA may in part be via switching off the antiangiogenic switch mediated by TSR proteins and CD36.

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Bin Ren ◽  
Devi P Ramakrishnan ◽  
Brian Walcott ◽  
Yiliang Chen ◽  
Brad Best ◽  
...  

Lysophosphatidic acid (LPA), a bioactive signaling phospholipid, down-regulates CD36 expression in microvascular endothelial cells (MVECs) via protein kinase PKD-1 signaling, thereby abolishing endothelial cell responses to its antiangiogenic ligand thrombospondin-1. However, little is known regarding mechanisms by which MVEC-specific CD36 transcription is regulated. We describe that in MVECs LPA represses CD36 transcription by activating a PKD-1 signaling that induces formation of a HDAC7/NCoR1/FoxO1 complex in the nucleus. Promoter analysis first identified FoxO1 as a transcription factor responsible for the CD36 transcription, which was confirmed by a chromatin-immunoprecipitation assay. Using a combination of PKD-1 gene transduction with co-immmunoprecipitation assay, we showed an increased interaction of HDAC7/NCoR1 with FoxO1 in response to LPA. However, HDAC7 and FoxO1 interaction was attenuated with PKD-1 silencing. Furthermore, based on results from an angiogenesis profiling with real time qPCR, doxycycline inducible constitutively active PKD-1 plasmids were transduced into tumor associated endothelial cells using a Lentiviral system to induce the PKD-1 expression. The results showed that turning off CD36 transcription reprograms by PKD-1 signaling was accompanied by an induced expression of ephrin B2 and activation of MAPK/ERK1/2 signaling, which are two critical “molecular signatures” involved in arteriogenesis. Moreover, three dimensional spheroid assay, a modified Boyden Chamber assay and in vivo Matrigel assay revealed that turning off CD36 transcription promoted angiogenesis in vitro and in vivo in a PKD-1-dependent manner. Immunofluorescence microscopy also showed the presence of this signaling pathway in the vasculature of Lewis lung carcinomas grown in cd36 deficient mice. In summary, our data suggest that a LPA-PKD-1-HDAC7/NCoR1-FoxO1 signaling axis is critical for transcriptional regulation of CD36 and mediates silencing of this antiangiogenic switch. This subsequently results in MVEC reprogramming for proangiogenic and arteriogenic responses. Therefore, targeting this signaling cascade could be a novel approach for malignant tumors, cardiovascular ischemia and other thrombotic diseases.


Author(s):  
Huiming Chen ◽  
Junfeng Zhao ◽  
Ningning Jiang ◽  
Zheng Wang ◽  
Chang Liu

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal diseases, with a 5-year survival rate of less than 10% because of the limited knowledge of tumor-promoting factors and their underlying mechanism. Diabetes mellitus (DM) and hyperglycemia are risk factors for many cancers, including PDAC, that modulate multiple downstream signaling pathways, such as the wingless/integrated (Wnt)/β-catenin signaling pathway. However, whether hyperglycemia promotes PDAC initiation and progression by activating the Wnt/β-catenin signaling pathway remains unclear. Methods: In this study, we used bioinformatics analysis and clinical specimen analysis to evaluate the activation states of the Wnt/βcatenin signaling pathway. In addition, colony formation assays, Transwell assays and wound-healing assays were used to evaluate the malignant biological behaviors of pancreatic cancer cells (PCs) under hyperglycemic conditions. To describe the effects of hyperglycemia and the Wnt/β-catenin signaling pathway on the initiation of PDAC, we used pancreatitis-driven pancreatic cancer initiation models in vivo and pancreatic acinar cell 3-dimensional culture in vitro. Results: Wnt/β-catenin signaling pathway-related molecules were overexpressed in PDAC tissues/cells and correlated with poor prognosis in PDAC patients. In addition, hyperglycemia exacerbated the abnormal activation of β-catenin in PDAC and enhanced the malignant biological behaviors of PCs in a Wnt/β-catenin signaling pathway-dependent manner. Indeed, hyperglycemia accelerated the formation of pancreatic precancerous lesions by activating the Wnt/β-catenin signaling pathway in vivo and in vitro. Conclusion: Hyperglycemia promotes pancreatic cancer initiation and progression by activating the Wnt/β-catenin signaling pathway.


2006 ◽  
Vol 19 (1) ◽  
pp. 205873920601900 ◽  
Author(s):  
M. Bongrazio ◽  
L. DA Silva-Azevedo ◽  
E.C. Bergmann ◽  
O. Baum ◽  
B. Hinz ◽  
...  

Binding of thrombospondin-1 (TSP-1) to the CD36 receptor inhibits angiogenesis and induces apoptosis in endothelial cells (EC). Conversely, matrix-bound TSP-1 supports vessel formation. In this study we analyzed the shear stress-dependent expression of TSP-1 and CD36 in endothelial cells in vitro and in vivo to reveal its putative role in the blood flow-induced remodelling of vascular networks. Shear stress was applied to EC using a cone-and-plate apparatus and gene expression was analyzed by RT-PCR, Northern and Western blot. Angiogenesis in skeletal muscles of prazosin-fed (50 mg/1 drinking water; 4 d) mice was assessed by measuring capillary-to-fiber (C/F) ratios. Protein expression in whole muscle homogenates (WMH) or BS-1 lectin-enriched EC fractions (ECF) was analyzed by Western blot. Shear stress down-regulated TSP-1 and CD36 expression in vitro in a force- and time-dependent manner sustained for at least 72 h and reversible by restoration of no-flow conditions. In vivo, shear stress-driven increase of C/F in prazosin-fed mice was associated with reduced expression of TSP-1 and CD36 in ECF, while TSP-1 expression in WMH was increased. Down-regulation of endothelial TSP-1/CD36 by shear stress suggests a mechanism for inhibition of apoptosis in perfused vessels and pruning in the absence of flow. The increase of extra-endothelial (e.g. matrix-bound) TSP-1 could support a splitting type of vessel growth.


2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Jennifer S Esser ◽  
Susanne Rahner ◽  
Meike Deckler ◽  
Christoph Bode ◽  
Martin Moser

Introduction: Bone morphogenetic proteins (BMP) play a key role in vascular development. Previously, we have identified BMP endothelial cell precursor-derived regulator (BMPER), an extracellular BMP modulator, to increase the angiogenic activity of endothelial cells in a concentration-dependent manner. In this project we now investigate how the BMPER effect is mediated by key molecules of angiogenesis. Methods and Results: To assess the effect of BMPER on angiogenesis-related molecules we performed an angiogenesis antibody array with BMPER-stimulated human umbilical venous endothelial cells (HUVECs) and vice versa with BMPER-silenced HUVECs compared to control conditions, respectively. We detected increased protein expression of the anti-angiogenic thrombospondin-1 (TSP-1) 48 hours after siBMPER transfection and, consistently, decreased TSP-1 expression after stimulation with BMPER (60 ng/ml; 39% ± 7.3 N=4). Furthermore, the pro-angiogenic protein bFGF was increased after BMPER stimulation, which was confirmed by realtime-PCR and western blot analysis (288.8% ± 74.8 N=3). Additionally, we detected increased FGF receptor-1 protein expression (137.7% ± 0.4 N=3) as well as FGF signaling pathway activation. Next, we investigated the interaction of BMPER and the FGF signaling pathway in endothelial cell function. BMPER stimulation increased HUVEC angiogenic activity in matrigel, migration and spheroid assays and concomitant inhibition of FGF signaling by an anti-bFGF antibody effectively inhibited the pro-angiogenic BMPER effect. Silencing of BMPER decreased the expression of FGFR1 and, accordingly, stimulation of BMPER-silenced cells with bFGF showed decreased angiogenic endothelial cell activity (65%) compared to control. The angiogenic activity of bFGF was also reduced in C57BL/6_Bmper +/- mice as assessed in the matrigel plug assay. Ex vivo aortic ring assays of C57BL/6_Bmper +/- mice confirmed a specific effect for bFGF but not for VEGF. Conclusion: In summary, BMPER inhibits the expression of the anti-angiogenic TSP-1 and increased the expression as well as activation of the pro-angiogenic FGF signaling pathway, which overall lead to the promotion of angiogenesis.


2021 ◽  
Author(s):  
Jinju Li ◽  
Rongge Shao ◽  
Qiuwen Xie ◽  
XueKe Du

Abstract Purpose:Ulinastatin (UTI) is an endogenous protease inhibitor with potent anti-inflammatory, antioxidant and organ protective effects. The inhibitor has been reported to ameliorate inflammatory lung injury but precise mechanisms remain unclear. Methods: An in vivo model of lung injury has been constructed by intratracheal infusion of lipopolysaccharide (LPS). The number of neutrophils and the phagocytosis of apoptotic neutrophils were observed by Diff- Quick method. Lung injury was observed by HE staining .BALF cells were counted by hemocytometer and concentrations of protein plus inflammatory factors were measured with a BCA test kit. During in vitro experiments, RAW264.7 cells were pretreated with UTI (1000 and 5000U/ mL), stained with CellTrackerTM Green B0DIPYTM and HL60 cells added with UV-induced apoptosis and PKH26 Red staining. The expression of ERK5\Mer related proteins was detected by western blot and immunofluorescence.Results: An in vivo model of lung injury has been constructed by intratracheal infusion of lipopolysaccharide (LPS). UTI treatment enhanced the phagocytotic effect of mouse alveolar macrophages on neutrophils, alleviated lung lesions, decreased the pro-inflammatory factor and total protein content of BALF and increased levels of anti-inflammatory factors. in vitro experiments ,UTI enhanced the phagocytosis of apoptotic bodies by RAW264.7 cells in a dose-dependent manner. Increased expression levels of ERK5 and Mer by UTI were shown by Western blotting and immunofluorescence.Conclusions: UTI mediated the activation of the ERK5/Mer signaling pathway, enhanced phagocytosis of neutrophils by macrophages and improved lung inflammation. The current study indicates potential new clinical approaches for accelerating the recovery from lung inflammation.


2011 ◽  
Vol 22 (14) ◽  
pp. 2509-2519 ◽  
Author(s):  
Jian J. Liu ◽  
Rebecca A. Stockton ◽  
Alexandre R. Gingras ◽  
Ararat J. Ablooglu ◽  
Jaewon Han ◽  
...  

Activation of Rap1 small GTPases stabilizes cell–cell junctions, and this activity requires Krev Interaction Trapped gene 1 (KRIT1). Loss of KRIT1 disrupts cardiovascular development and causes autosomal dominant familial cerebral cavernous malformations. Here we report that native KRIT1 protein binds the effector loop of Rap1A but not H-Ras in a GTP-dependent manner, establishing that it is an authentic Rap1-specific effector. By modeling the KRIT1–Rap1 interface we designed a well-folded KRIT1 mutant that exhibited a ∼40-fold-reduced affinity for Rap1A and maintained other KRIT1-binding functions. Direct binding of KRIT1 to Rap1 stabilized endothelial cell–cell junctions in vitro and was required for cardiovascular development in vivo. Mechanistically, Rap1 binding released KRIT1 from microtubules, enabling it to locate to cell–cell junctions, where it suppressed Rho kinase signaling and stabilized the junctions. These studies establish that the direct physical interaction of Rap1 with KRIT1 enables the translocation of microtubule-sequestered KRIT1 to junctions, thereby supporting junctional integrity and cardiovascular development.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yu Zhan ◽  
Xuegui Tang ◽  
Hong Xu ◽  
Shiyu Tang

Background. Maren pills have been used to treat constipation. Aquaporin 3 (AQP3) plays a vital role in regulating water transfer in the colon. It has been reported that the downregulation of AQP3 can regulate liquid water metabolism and intestinal permeability in irritable bowel syndrome (IBS) rats’ colon via NF-κB pathway. In this study, we investigated whether the laxative effect of Maren pills is associated with the regulation of AQP3 and NF-κB signaling pathway in the colon. Methods. The compound diphenoxylate suspension-induced STC rats received Maren pills intragastrically for 1 consecutive week to evaluate the laxative effect of Maren pills involving the regulation of AQP3 and NF-κB signaling pathway. Moreover, human intestinal epithelial cells (HT-29) were treated with drug serum to obtain in vitro data. Results. Our results revealed that treatment with Maren pills increased the stool number, moisture content of feces, and intestinal transit rate in a dose-dependent manner. Maren pills significantly increased the AQP3, fibrosis transmembrane conductance regulator (CFTR), and protein kinase A (PKA) proteins in the colon of rats and in HT-29 cells. Mechanistically, Maren pills obviously inhibited the activation of NF-κB pathway in the colon of rats and in HT-29 cells. Conclusion. These results suggest that the laxative effect of Maren pills is associated with the increased expression of AQP3 by downregulating NF-κB signal pathway.


2014 ◽  
Vol 997 ◽  
pp. 225-228 ◽  
Author(s):  
Yan Ling Wu ◽  
Li Wen Shen ◽  
Yan Ping Ding ◽  
Yoshimasa Tanaka ◽  
Wen Zhang

Benzamide derivatives have been shown to have antitumor activity in various tumor cell lines in vitro as well as in vivo. In this study, we examined the anti-proliferative effect of four benzamide derivativeson Hela, H7402, and SK-RC-42 tumor cell lines in vitro by means of Real-Time cell assay (RTCA), and found that four benzamide derivatives suppressed proliferation of tumor cells in a time-and dose-dependent manner. The anti-proliferative activity of benzamide derivatives demonstrated that theycould be promising lead compounds for developing therapeutic agents for malignant tumors.


2011 ◽  
Vol 39 (06) ◽  
pp. 1193-1206 ◽  
Author(s):  
De-Peng Jiang ◽  
Qi Li ◽  
Jie Yang ◽  
Juliy M. Perelman ◽  
Victor P. Kolosov ◽  
...  

The aim of this study was to investigate the influence of scutellarin on mucus production induced by human neutrophil elastase (HNE) and the possible in vitro and in vivo mechanisms. To this purpose, cells were incubated with saline, scutellarin or gefitinib for 60 min and exposed to 0.1 μM HNE for 24 h. After being pretreated respectively with saline, scutellarin or gefitinib, rats were challenged intratracheally with HNE by means of nebulization for 30 days. The expression of mucin (MUC) 5AC, protein kinase C (PKC), and extracellular signal-regulated kinase 1/2 (ERK1/2) was assessed by ELISA, RT-PCR or Western blotting. The results showed that scutellarin inhibited MUC5AC mRNA and protein expressions induced by HNE in a concentration-dependent manner in vitro. In the in vivo model, scutellarin significantly attenuated MUC5AC mRNA expression and goblet cell hyperplasia in rats treated with HNE for 30 days, as well as decreased the phosporylation of PKC and ERK1/2 compared to the HNE control group. Therefore, our study showed that scutellarin could prevent mucus hypersecretion by inhibiting the PKC-ERK signaling pathway. Inhalation scutellarin may be valuable in the treatment of chronic inflammatory lung disease.


Author(s):  
Li Zhang ◽  
Zongtao Chai ◽  
Siyuan Kong ◽  
Jiling Feng ◽  
Man Wu ◽  
...  

Hepatocellular carcinoma (HCC) is one of the malignant tumors with poor prognosis. High expression level of cofilin 1 (CFL1) has been found in many types of cancers. However, the role of CFL1 in HCC hasn’t been known clearly. Here, we found that CFL1 was up regulated in human HCC and significantly associated with both overall survival and disease-free survival in HCC patients. Nujiangexanthone A (NJXA), the caged xanthones, isolated from gamboge plants decreased the expression of CFL1, which also inhibited the migration, invasion and metastasis of HCC cells in vitro and in vivo. Down regulation of CFL1 inhibited aggressiveness of HCC cells, which mimicked the effect of NJXA. Mechanism study indicated that, knockdown of CFL1 or treatment with NJXA increased the level of F-actin and disturbed the balance between F-actin and G-actin. In conclusion, our findings reveal the role of CFL1 in HCC metastasis through the CFL1/F-actin axis, and suggest that CFL1 may be a potential prognostic marker and a new therapeutic target. NJXA can effectively inhibit the metastasis of HCC cells by down regulating the expression of CFL1, which indicates the potential of NJXA for preventing metastasis in HCC.


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