Clinical implications of placenta-derived angiogenic/anti-angiogenic biomarkers in pre-eclampsia.

Pre-eclampsia (PE) is a devastating systemic disease which results in maternal hypertension with multi-organ failure due to angiogenic imbalance, characterized by lack of circulating pro-angiogenic factors and excess of anti-angiogenic factors. These factors are crucial for understanding the pathophysiology of PE since they serve as a critical link from placental dysfunction to the clinical syndrome of systemic endothelial dysfunction in the disease. Moreover, utilizing these angiogenic/anti-angiogenic biomarkers can be helpful in risk stratifying and the early detection of PE, which allows for timely intervention to improve maternal and neonatal outcomes. In this review, we summarize updated perspectives of the angiogenic imbalance in PE with detailed characterization of key factors involved in the pathogenesis and how the developed biomarkers can be used in clinical settings as diagnostic tools and as possible therapeutic targets of PE.

Tumor Angiogenesis and VEGFR-2: Mechanism, Pathways and Current Biological Therapeutic Interventions.

BACKGROUND: Angiogenesis, involving the formation of new blood vessels from preexisting vessels, caters an important biological phenomenon for the growth and development of bodily structures in the human body. Regulation of angiogenesis in non-pathological conditions takes place through a well-defined balanced angiogenic-switch, which upon exposure to various pathological conditions may get altered. This makes the cells change their normal behavior resulting in uncontrolled division and angiogenesis. METHODS: The current review tries to present a brief framework of angiogenesis and tumor progression phenomenon along with the latest therapeutic interventions against VEGFR-2 and its future directions. RESULTS: The tumor angiogenic pathways functioning in diverse mechanisms via sprouting angiogenesis, intussusceptive angiogenesis, vascular co-option, vascular mimicry, and glomeruloid angiogenesis are normally activated by varied angiogenic stimulators and their receptors are interrelated to give rise to specialized signaling pathways. Amongst these receptors, VEGFR-2 is found as one of the key, critical mediators in tumor angiogenesis and is seen as a major therapeutic target for combating angiogenesis. Though a number of anti-angiogenic drugs like Ramucirumab, Sunitinib, Axitinib, Sorafenib, etc. showing good survival rates have been developed and approved by FDA against VEGFR-2, but these have also been found to be associated with serious health effects and adverse reactions. CONCLUSION: An improved or alternative treatment is needed shortly that has a higher survival rate with the least side effects. Innovative strategies, including personalized medicine, nano-medicine, and cancer immunotherapy have also been outlined as an alternative treatment with a discussion on advancements and improvements required for their implementation methods.

BACH family members regulate angiogenesis and lymphangiogenesis by modulating VEGFC expression.

Angiogenesis and lymphangiogenesis are key processes during embryogenesis as well as under physiological and pathological conditions. Vascular endothelial growth factor C (VEGFC), the ligand for both VEGFR2 and VEGFR3, is a central lymphangiogenic regulator that also drives angiogenesis. Here, we report that members of the highly conserved BACH (BTB and CNC homology) family of transcription factors regulate VEGFC expression, through direct binding to its promoter. Accordingly, down-regulation of bach2a hinders blood vessel formation and impairs lymphatic sprouting in a Vegfc-dependent manner during zebrafish embryonic development. In contrast, BACH1 overexpression enhances intratumoral blood vessel density and peritumoral lymphatic vessel diameter in ovarian and lung mouse tumor models. The effects on the vascular compartment correlate spatially and temporally with BACH1 transcriptional regulation of VEGFC expression. Altogether, our results uncover a novel role for the BACH/VEGFC signaling axis in lymphatic formation during embryogenesis and cancer, providing a novel potential target for therapeutic interventions.

Structural bases that underline Trypanosoma cruzi calreticulin proinfective, antiangiogenic and antitumor properties.

Microbes have developed mechanisms to resist the host immune defenses and some elicit antitumor immune responses. About 6 million people are infected with Trypanosoma cruzi, the protozoan agent of Chagas' disease, the sixth neglected tropical disease worldwide. Eighty years ago, G. Roskin and N. Klyuyeva proposed that T. cruzi infection mediates an anti-cancer activity. This observation has been reproduced by several other laboratories, but no molecular basis has been proposed. We have shown that the highly pleiotropic chaperone calreticulin (TcCalr, formerly known as TcCRT), translocates from the parasite ER to the exterior, where it mediates infection. Similar to its human counterpart HuCALR (formerly known as HuCRT), TcCalr inhibits C1 in its capacity to initiate the classical pathway of complement activation. We have also proposed that TcCalr inhibits angiogenesis and it is a likely mediator of antitumor effects. We have generated several in silico structural TcCalr models to delimit a peptide (VC-TcCalr) at the TcCalr N-domain. Chemically synthesized VC-TcCalr did bind to C1q and was anti-angiogenic in Gallus gallus chorioallantoic membrane assays. These properties were associated with structural features, as determined in silico. VC-TcCalr, a strong dipole, interacts with charged proteins such as collagen-like tails and scavenger receptors. Comparatively, HuCALR has less polarity and spatial stability, probably due to at least substitutions of Gln for Gly, Arg for Lys, Arg for Asp and Ser for Arg that hinder protein-protein interactions. These differences can explain, at least in part, how TcCalr inhibits the complement activation pathway and has higher efficiency as an antiangiogenic and antitumor agent than HuCALR.

P2Y4/TSP-1/TGF-ß1/pSmad2/3 pathway contributes to acute generalized seizures induced by kainic acid.

Epilepsy is accompanied by angiogenesis and blood-brain barrier (BBB) disruption. The transforming growth factor-ß1 (TGF-ß1)/phosphorylated small mothers against decapentaplegic 2 and 3 (pSmad2/3)/vascular endothelial growth factor (VEGF) pathway, activated by thrombospondin-1 (TSP-1), which is further regulated by Y type P2 purinergic receptor activity, may participate in angiogenesis. We sought to investigate the relationship between the P2R/TSP-1/TGF-ß1/pSmad2/3/VEGF pathway, angiogenesis, and BBB damage in a kainic acid (KA) model of acute generalized seizure. Our results demonstrated that KA-induced seizures were accompanied by angiogenesis and BBB damage. In addition, expression of TSP-1, TGF-ß1, and pSmad2/3 was increased. Rats treated with pyridoxal phosphate-6-azophenyl-2', 4'-disulfonic acid, a broad P2 receptor antagonist, or Reactive Blue 2, a potent P2Y4 receptor antagonist, showed significant attenuation of TSP-1 expression and Smad2/3 phosphorylation levels. Furthermore, angiogenesis, BBB damage, and acute seizure severity were also reduced. The inhibition of TSP-1 expression by siRNA or TGF-ß1 activation by Leu-Ser-Lys-Leu (LSKL) treatment prevented KA-induced phosphorylation of Smad2/3, angiogenesis, BBB damage, and acute seizures. Our results strongly indicate that the P2Y4/TSP-1/TGF-ß1/pSmad2/3/VEGF pathway plays an essential role in seizure pathophysiology and angiogenesis. Therapeutic interventions targeting this pathway may offer new treatment options for acute seizures.

Analysis of Differentially Expressed lncRNAs and mRNAs for the Identification of Hypoxia-Regulated Angiogenic Genes in Colorectal Cancer by RNA-Seq.

BACKGROUND Hypoxia is an important feature of solid tumors and related to a perturbed blood supply in pathophysiologies. The aim of our research was to analyze the hypoxia response and elaborate its potential functions in colorectal cancer. MATERIAL AND METHODS The lncRNAs and mRNAs expression profile were analyzed in colorectal cancer cell line SW480 by RNA sequencing, and the functions and pathways of differentially expressed genes were screened by Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis. RESULTS In this study, 77 lncRNAs and 1327 mRNAs were identified as differentially expressed. We discovered several novel lncRNAs, such as RP11-126K1.2, RP3-438O4.4, LINC01119, CTB-22K21.2, RP11-798M19.6, and RP11-2B6.3, which had not been previously reported in regulation by hypoxia. KEGG and GO analyses identified that the differentially expressed changes in mRNAs were mainly related to regulation of basic metabolic processes and gene transcription processes and were involved in several classical pathways which were linked to cancer. CONCLUSIONS Taken together, the present findings elucidate a set of differentially expressed lncRNAs and mRNAs involved in the hypoxia response process of colorectal cancer, which may serve as a candidate diagnostic biomarker and help to explain the mechanism of initial event in colorectal carcinogenesis in colorectal cancer.

α-Methyl-prednisolone normalizes the PKC mediated brain angiogenesis in dystrophic mdx mice.

A fraction of patients affected by Duchenne Muscular Dystrophy (DMD) shows mental disability as a consequence of neuronal and metabolic alteration. In this study, we evaluated the effect of α-methyl-prednisolone (PDN) on the expression of the angiogenic marker HIF1α, VEGFA and VEGFR-2 (FLK1) in correlation with PKC expression in the brain of mdx mouse, an experimental model of DMD. We demonstrated that HIF1α, VEGFA and FLK1 are overexpressed in the brain of dystrophic mdx mice in parallel with an increase of PKC expression and reduction of the tight junctions Occludin leading to altered angiogenesis. Moreover, we demonstrated that PDN treatment induces a significant reduction in the HIF1α, VEGF, FLK1, and PKC mRNA and proteins levels and restores Occludin expression reducing its phosphorylation pattern. Our results suggest a new mechanism of action of PDN that through PKC suppression normalizes the angiogenesis in dystrophic mdx brains.

Adipocytokines, inflammatory, epigenetic instability & angiogenesis biomarkers in type 2 diabetic Egyptian women with breast cancer.

Obesity is the main determinant of type 2 diabetes. Some adipocytokines play important roles in diabetic complications. Lipid transport is an important aspect of lipid metabolism in cancer. Present study aimed to evaluate the effect of some adipocytokines, inflammatory, epigenetic instability & angiogenesis biomarkers in type 2 diabetic Egyptian women with breast cancer. Study Design was performed on eighty females divided into 20 healthy subjects (Group I), 20 patients with type 2 diabetes (Group II), 20 patients with breast cancer (Group III) & 20 patients with diabetes and breast cancer (Group IV). Demographic data & body mass index have been collected. Biochemical analysis included fasting & postprandial blood glucose, lipid profile, fatty acid-binding proteins-4 (FABP-4), tumor necrosis factor-α (TNF-α), vascular endothelial growth factor (VEGF), 8-hydroxy-2'-deoxyguanosine (8-OHdG) & thioredoxin reductase (TrxR) activity. Results revealed significant increase in FABP-4, TNF-α, VEGF, 8-OHdG and significant decreased TrxR activity in diabetic patients with breast cancer in comparison with other groups. These changes were evident in breast cancer subjects than diabetic and healthy cases and in diabetic than healthy cases. Conclusion: This study confirmed the role of FABP-4 in pathogenesis of type 2 diabetes & breast cancer via enhancing angiogenesis, inflammatory and epigenetic instability biomarkers.

The A to Z of modulated cell patterning by mammalian thioredoxin reductases.

Mammalian thioredoxin reductases (TrxRs) are selenocysteine-containing proteins (selenoproteins) that propel a large number of functions through reduction of several substrates including the active site disulfide of thioredoxins (Trxs). Well-known enzymatic systems that in turn are supported by Trxs and TrxRs include deoxyribonucleotide synthesis through ribonucleotide reductase, antioxidant defense through peroxiredoxins and methionine sulfoxide reductases, and redox modulation of a number of transcription factors. Although these functions may be essential for cells due to crucial roles in maintenance of cell viability and proliferation, findings during the last decade reveal that mammals have major redundancy in their cellular reductive systems. The synthesis of glutathione (GSH) and reductive functions of GSH-dependent pathways typically act in parallel with Trx-dependent pathways, with only one of these systems often being sufficient to support viability. Importantly, this does not imply that a modulation of the Trx system will remain without consequences, even when GSH-dependent pathways remain functional. As suggested by several recent findings, the Trx system in general and the TrxRs in particular, function as key regulators of signaling pathways. In this review article we will discuss findings that collectively suggest that modulation in mammalian systems of cytosolic TrxR1 (TXNRD1) or mitochondrial TrxR2 (TXNRD2) influence cell patterning and cellular stress responses. Effects of lower activities include increased adipogenesis, insulin responsiveness, glycogen accumulation, hyperproliferation, and distorted embryonic development, while increased activities correlate with decreased proliferation and extended lifespan, as well as worse cancer prognosis. The molecular mechanisms that underlie these diverse effects, involving regulation of protein phosphorylation cascades and of key transcription factors that guide cellular differentiation pathways, will be discussed. We conclude that the selenium-dependent oxidoreductases TrxR1 and TrxR2 should be considered as key components of signaling pathways that control cell differentiation and cellular stress responses.

The roles of vasohibin and its family members: Beyond angiogenesis modulators.

Vasohibin-1 is an intrinsic angiogenesis inhibitor, and is expressed in endothelial cells via induction by pro-angiogenesis factors. It is known to inhibit several processes of angiogenesis, with different mechanisms from extrinsic angiogenesis inhibitors. Vasohibin-2 is mainly expressed by mononuclear cells which have been mobilized from bone marrow. It not only promotes angiogenesis, but also modulates the releases of FGF-2 and VEGF, which are the two major inducers for vasohibin1. Hypoxic environment induces the expression of hypoxia-inducible Factor 1α with a result of VEGF release nearly in all tumor cell lines and tissues. However, it has been observed that hypoxia reduces the inducible effects of VEGF on vasohibin, which indicates that a complicated mechanism exists in the angiogenesis. Vasohibin and its family members play important roles in both the physiological and pathological procedures, in contrary but complementary patterns. Furthermore, human aortic smooth muscle cells and fibroblast have also been detected to express vasohibin on a moderate to weak scale range. Recently, the results of an increasing number of studies in vivo have shown that vasohibin can also be detected in several cancers, and is associated with micro-vessel densities, histology grades, invasions, poor clinical features, metastasis, and dissemination in abdominal cavities, as well as EMT. In more recent reports, it has been confirmed that, along with being angiogenesis regulators, a variety of other roles have been associated with this family. The focus of this study was the upstream regulatory mechanisms of vasohibin expressions, and their role in regard to the downstream target proteins of vasohibin, especially in carcinoma. Vasohibin is considered to be an original angiogenesis inhibitor, and has a much broader significance in pathological processes. It can be taken as an independent prognostic factor, as well as a potential strategy for cancer therapy programs.

Inhibition of chemokine (C-X-C motif) receptor four (CXCR4) at the fetal-maternal interface during early gestation in sheep: alterations in expression of chemokines, angiogenic factors and their receptors.

Chemokine (C-X-C motif) ligand 12 (CXCL12) and its receptor, chemokine (C-X-C motif) receptor 4 (CXCR4), are involved in significant biological processes associated with early pregnancy including increasing trophoblast invasion and stimulating placental vascularization. To further elucidate functions of CXCL12-CXCR4 signaling during early gestation, our objective was to inhibit CXCR4 in vivo using a CXCR4 antagonist, AMD3100. We hypothesized that inhibition of CXCR4 would negatively affect chemokine and angiogenic factor regulation imperative for placental development in sheep. Osmotic pumps containing PBS (control) or AMD3100 (CXCR4 antagonist) were surgically installed ipsilateral to the corpus luteum on d 12 of gestation and administered treatments directly into the uterine lumen. Maternal (caruncle and intercaruncle) and fetal membrane tissues were collected on d 23 of gestation and mRNA and protein expression were analyzed for vascular endothelial growth factor (VEGF), kinase insert domain receptor (KDR), fms related tyrosine kinase 1 (FLT1), fibroblast growth factor 2 (FGF2), angiopoietin 1 (ANGPT1), hypoxia inducible factor 1 ɑ subunit (HIF1A), CXCL12, and its corresponding receptors (CXCR4 and CXCR7). Immunohistochemical procedures were performed for analysis of CXCL12 and cell proliferation. In caruncle tissue ipsilateral to the pump, mRNA for KDR, ANGPT1, HIF1A, and CXCL12 increased (P < 0.05) in treated ewes compared to control, whereas caruncle tissue contralateral to the pump had increased expression (P < 0.05) of KDR, and CXCL12 in treated ewes. In fetal membrane, CXCR4 mRNA and protein decreased (P < 0.05), while VEGF protein decreased (P < 0.05) in caruncle and fetal membrane tissue from treated ewes. Results from this study highlight the importance of CXCL12-CXCR4 signaling at the fetal-maternal interface. Inhibiting this axis may disrupt typical regulation of angiogenic factors needed for placental development and embryo growth.

Effects of Cytokines and TLR Ligands on the Production of PlGF and sVEGFR1 in Primary Trophoblasts.

AIM: Cytokines such as tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) play an important role in maintaining pregnancy. Toll-like receptors (TLRs) have also been associated with innate immune responses during pregnancy. Placenta growth factor (PlGF) is one of the angiogenic factors and soluble vascular endothelial growth factor receptor 1 (sVEGFR1) is one of the antiangiogenic factors that regulate PlGF function. To elucidate the effects of cytokines and TLR ligands on the production of angiogenic and antiangiogenic factors in trophoblasts, we examined the production of PlGF and sVEGFR1 from trophoblasts following stimulation with cytokines and TLR ligands. METHODS: Villous tissues were obtained from healthy pregnant women who had had an artificial abortion. The trophoblasts were isolated from villous tissues. Subsequently, trophoblasts were treated with TNF-α, IFN-γ and TLR ligands. The levels of PlGF and sVEGFR1 were measured by enzyme-linked immunosorbent assay. The expression of those mRNA was analyzed using quantitative reverse transcription PCR. RESULTS: The production of PlGF in trophoblasts increased by the addition of TNF-α or IFN-γ and decreased by TLR4 ligand. sVEGFR1 levels also increased by following the stimulation with IFN-γ or TLR ligand. CONCLUSIONS: Cytokines such as TNF-α and IFN-γ and TLR ligands may contribute to the production of angiogenic and antiangiogenic factors and may affect the placental formation.

Heat therapy promotes the expression of angiogenic regulators in human skeletal muscle.

Heat therapy has been shown to promote capillary growth in skeletal muscle and in the heart in several animal models, but the effects of this therapy on angiogenic signaling in humans are unknown. We evaluated the acute effect of lower body heating (LBH) and unilateral thigh heating (TH) on the expression of angiogenic regulators and heat shock proteins (HSPs) in healthy young individuals. Exposure to LBH (n = 18) increased core temperature (Tc) from 36.9 ± 0.1 to 37.4 ± 0.1°C (P < 0.01) and average leg skin temperature (Tleg) from 33.1 ± 0.1 to 39.6 ± 0.1°C (P < 0.01), but did not alter the levels of circulating angiogenic cytokines and bone marrow-derived proangiogenic cells (CD34(+)CD133(+)). In skeletal muscle, the change in mRNA expression from baseline of vascular endothelial growth factor (VEGF), angiopoietin 2 (ANGPT2), chemokines CCL2 and CX3CL1, platelet factor-4 (PF4), and several members of the HSP family was higher 30 min after the intervention in the individuals exposed to LBH (n = 11) compared with the control group (n = 12). LBH also reduced the expression of transcription factor FOXO1 (P = 0.03). Exposure to TH (n = 14) increased Tleg from 32.8 ± 0.2 to 40.3 ± 0.1°C (P < 0.05) but Tc remained unaltered (36.8 ± 0.1°C at baseline and 36.9 ± 0.1°C at 90 min). This intervention upregulated the expression of VEGF, ANGPT1, ANGPT2, CCL2, and HSPs in skeletal muscle but did not affect the levels of CX3CL1, FOXO-1, and PF4. These findings suggest that both LBH and TH increase the expression of factors associated with capillary growth in human skeletal muscle.

Hypoxia-inducible factor 1 in autoimmune diseases.

Autoimmune disorders are a complicated and varied group of diseases arising from inappropriate immune responses. Recent studies have demonstrated that ongoing inflammatory and immune responses are associated with increased oxygen consumption, a process resulting in localized tissue hypoxia within inflammatory lesions ("inflammatory hypoxia"), in which hypoxia-inducible factor 1 (HIF-1), an oxygen-sensitive transcription factor that allows adaptation to hypoxia environments, has been shown to play an important function. HIF-1 is a regulator of angiogenesis and immune system. Besides, HIF-1-mediated metabolic shift and fibrosis may also play crucial roles in some autoimmune disorders. Firstly, we briefly summarize the role of HIF-1 in angiogenesis, immune responses and fibrosis. Secondly, we will show the major recent findings demonstrating a role for HIF-1 signaling in autoimmune disorders, including rheumatoid arthritis, inflammatory bowel disease, psoriasis, systemic sclerosis and multiple sclerosis. The growing evidences may prompt HIF-1 to be a new target for treatment of autoimmune diseases.

Angiogenesis-Related Markers and Prognosis After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Metastatic Colorectal Cancer.

BACKGROUND: Patients presenting with peritoneal metastases (PM) of colorectal cancer (CRC) can be curatively treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Angiogenesis is under control of multiple molecules of which HIF1a, SDF1, CXCR4, and VEGF are key players. We investigated these angiogenesis-related markers and their prognostic value in patients with PM arising from CRC treated with CRS and HIPEC. PATIENTS AND METHODS: Clinicopathological data and tissue specimens were collected in 2 tertiary referral centers from 52 patients who underwent treatment for isolated PM of CRC. Whole tissue specimens were subsequently analyzed for protein expression of HIF1a, SDF1, CXCR4, and VEGF by immunohistochemistry. Microvessel density (MVD) was analyzed by CD31 immunohistochemistry. The relationship between overall survival (OS) and protein expression as well as other clinicopathological characteristics was analyzed. RESULTS: Univariate analysis showed that high peritoneal cancer index (PCI), resection with residual disease and high expression of VEGF were negatively correlated with OS after treatment with CRS and HIPEC (P < 0.01, P < 0.01, and P = 0.02, respectively). However, no association was found between the other markers and OS (P > 0.05). Multivariate analysis showed an independent association between OS and PCI, resection outcome and VEGF expression (multivariate HR: 6.1, 7.8 and 3.8, respectively, P ≤ 0.05). CONCLUSIONS: An independent association was found between high VEGF expression levels and worse OS after CRS and HIPEC. The addition of VEGF expression to the routine clinicopathological workup could help to identify patients at risk for early treatment failure. Furthermore, VEGF may be a potential target for adjuvant treatment in these patients.

Heparin/Heparan sulfate proteoglycans glycomic interactome in angiogenesis: biological implications and therapeutical use.

Angiogenesis, the process of formation of new blood vessel from pre-existing ones, is involved in various intertwined pathological processes including virus infection, inflammation and oncogenesis, making it a promising target for the development of novel strategies for various interventions. To induce angiogenesis, angiogenic growth factors (AGFs) must interact with pro-angiogenic receptors to induce proliferation, protease production and migration of endothelial cells (ECs). The action of AGFs is counteracted by antiangiogenic modulators whose main mechanism of action is to bind (thus sequestering or masking) AGFs or their receptors. Many sugars, either free or associated to proteins, are involved in these interactions, thus exerting a tight regulation of the neovascularization process. Heparin and heparan sulfate proteoglycans undoubtedly play a pivotal role in this context since they bind to almost all the known AGFs, to several pro-angiogenic receptors and even to angiogenic inhibitors, originating an intricate network of interaction, the so called "angiogenesis glycomic interactome". The decoding of the angiogenesis glycomic interactome, achievable by a systematic study of the interactions occurring among angiogenic modulators and sugars, may help to design novel antiangiogenic therapies with implications in the cure of angiogenesis-dependent diseases.

Rapamycin inhibits oxidative and angiogenic mediators in diabetic retinopathy.

OBJECTIVE: To evaluate the role of rapamycin in the prevention of diabetic oxidative stress and the regulation of angiogenic factors. DESIGN: Experimental animal study. METHODS: Diabetes was induced in 20 adult male Wistar rats by a single intraperitoneal administration of streptozotocin (60 mg/kg). Rats were randomly assigned into diabetic and rapamycin groups (n = 10). Ten healthy normal adult male rats of same age formed the control group. All groups were followed for 3 months. Rapamycin group received 1 mg/kg rapamycin via orogastric gavage during the last 4 weeks. At the end of 12 weeks, rats were sacrificed and biochemical oxidative stress markers (malondialdehyde and nitrotyrosine), together with vascular endothelial growth factor, hypoxia-inducible factor-1α, and pigment epithelium-derived factor, were measured in the retina. Blood biochemical analyses were also done. RESULTS: In the diabetic group, retinal malondialdehyde and nitrotyrosine levels were increased in comparison with control and rapamycin groups (p < 0.05). Rapamycin suppressed oxidative stress and showed a beneficial effect. It also decreased all angiomodulator cytokines compared with the diabetic group (p < 0.05). Correspondingly, rapamycin also decreased plasma malondialdehyde levels compared with the diabetic group (p = 0.037). CONCLUSIONS: Rapamycin may have a protective role against diabetes-induced oxidative retinal injury and may decrease angiomodulator cytokines.

CD47-dependent immunomodulatory and angiogenic activities of extracellular vesicles produced by T cells.

Intercellular communication is critical for integrating complex signals in multicellular eukaryotes. Vascular endothelial cells and T lymphocytes closely interact during the recirculation and trans-endothelial migration of T cells. In addition to direct cell-cell contact, we show that T cell derived extracellular vesicles can interact with endothelial cells and modulate their cellular functions. Thrombospondin-1 and its receptor CD47 are expressed on exosomes/ectosomes derived from T cells, and these extracellular vesicles are internalized and modulate signaling in both T cells and endothelial cells. Extracellular vesicles released from cells expressing or lacking CD47 differentially regulate activation of T cells induced by engaging the T cell receptor. Similarly, T cell-derived extracellular vesicles modulate endothelial cell responses to vascular endothelial growth factor and tube formation in a CD47-dependent manner. Uptake of T cell derived extracellular vesicles by recipient endothelial cells globally alters gene expression in a CD47-dependent manner. CD47 also regulates the mRNA content of extracellular vesicles in a manner consistent with some of the resulting alterations in target endothelial cell gene expression. Therefore, the thrombospondin-1 receptor CD47 directly or indirectly regulates intercellular communication mediated by the transfer of extracellular vesicles between vascular cells.

Anti-angiogenic effect of triptolide in rheumatoid arthritis by targeting angiogenic cascade.

Rheumatoid arthritis (RA) is characterized by a pre-vascular seriously inflammatory phase, followed by a vascular phase with high increase in vessel growth. Since angiogenesis has been considered as an essential event in perpetuating inflammatory and immune responses, as well as supporting pannus growth and development of RA, inhibition of angiogenesis has been proposed as a novel therapeutic strategy for RA. Triptolide, a diterpenoid triepoxide from Tripterygium wilfordii Hook F, has been extensively used in treatment of RA patients. It also acts as a small molecule inhibitor of tumor angiogenesis in several cancer types. However, it is unclear whether triptolide possesses an anti-angiogenic effect in RA. To address this problem, we constructed collagen-induced arthritis (CIA) model using DA rats by the injection of bovine type II collagen. Then, CIA rats were treated with triptolide (11-45 µg/kg/day) starting on the day 1 after first immunization. The arthritis scores (P<0.05) and the arthritis incidence (P<0.05) of inflamed joints were both significantly decreased in triptolide-treated CIA rats compared to vehicle CIA rats. More interestingly, doses of 11~45 µg/kg triptolide could markedly reduce the capillaries, small, medium and large vessel density in synovial membrane tissues of inflamed joints (all P<0.05). Moreover, triptolide inhibited matrigel-induced cell adhesion of HFLS-RA and HUVEC. It also disrupted tube formation of HUVEC on matrigel and suppressed the VEGF-induced chemotactic migration of HFLS-RA and HUVEC, respectively. Furthermore, triptolide significantly reduced the expression of angiogenic activators including TNF-α, IL-17, VEGF, VEGFR, Ang-1, Ang-2 and Tie2, as well as suppressed the IL1-ß-induced phosphorylated of ERK, p38 and JNK at protein levels. In conclusion, our data suggest for the first time that triptolide may possess anti-angiogenic effect in RA both in vivo and in vitro assay systems by downregulating the angiogenic activators and inhibiting the activation of mitogen-activated protein kinase downstream signal pathway.

Angiogenesis and vascular functions in modulation of obesity, adipose metabolism, and insulin sensitivity.

White and brown adipose tissues are hypervascularized and the adipose vasculature displays phenotypic and functional plasticity to coordinate with metabolic demands of adipocytes. Blood vessels not only supply nutrients and oxygen to nourish adipocytes, they also serve as a cellular reservoir to provide adipose precursor and stem cells that control adipose tissue mass and function. Multiple signaling molecules modulate the complex interplay between the vascular system and the adipocytes. Understanding fundamental mechanisms by which angiogenesis and vasculatures modulate adipocyte functions may provide new therapeutic options for treatment of obesity and metabolic disorders by targeting the adipose vasculature.