A customized program for the identification of conserved protein sequence motifs.

We searched for viral protein sequences that could be important for tissue tropism. To achieve this goal, human pathogenic viruses were classified according to the tissue they infect (e.g., pulmonary), irrespective of whether they were enveloped or non-enveloped RNA or DNA viruses. Next, we developed an amino acid sequence alignment program and identified the conserved amino acid motif, VAIVLGG, in alphaviruses. The VAIVLGG sequence is located on the structural capsid protein of the chikungunya virus, a mosquito-borne arthrogenic member of the alphaviruses. Capsid protein translocation onto the host cell membrane is a required step for virion budding. Our identified VAIVLGG consensus sequence might potentially be used for developing a pan-vaccine effective against alphaviruses.

Cardiac biomarkers: a focus on cardiac regeneration.

HISTORICALLY, BIOMARKERS HAVE BEEN USED IN TWO MAJOR WAYS TO MAINTAIN AND IMPROVE BETTER HEALTH STATUS: first, for diagnostic purposes, and second, as specific targets to treat various diseases. A new era in treatment and even cure for the some diseases using reprograming of somatic cells is about to be born. In this approach, scientists are successfully taking human skin cells (previously considered terminally-differentiated cells) and re-programming them into functional cardiac myocytes and other cell types in vitro. A cell reprograming approach for treatment of cardiovascular diseases will revolutionize the field of medicine and significantly expand the human lifetime. Availability of a comprehensive catalogue for cardiac biomarkers is necessary for developing cell reprograming modalities to treat cardiac diseases, as well as for determining the progress of reprogrammed cells as they become cardiac cells. In this review, we present a comprehensive survey of the cardiac biomarkers currently known.

Delaying DLA-haploidentical hematopoietic cell transplantation after total body irradiation.

Exposure to accidental or deliberate radiation poses a threat to public health, proving lethal at higher doses in large part because of deleterious effects on marrow. In those cases, allogeneic hematopoietic cell transplantation (HCT) might be required to restore marrow function. Most radiation accident victims will have HLA-haploidentical relatives who could serve as HCT donors. Here, we assessed in a canine HCT model the total body irradiation (TBI) doses after which transplants might be required and successful engraftment would be possible. In an attempt at mimicking the logistical problems likely to exist after radiation accidents, 4-, 8- or 10-day intervals were placed between TBI and HCT. To keep the experimental readout simple, no graft-versus-host disease (GVHD) prevention was administered. All dogs transplanted after a 4-day delay following 700 or 920 cGy TBI successfully engrafted, whereas virtually all those given 450 or 600 cGy rejected their grafts. Transplant delays of 8 and 10 days following 920 cGy TBI also resulted in successful engraftment in most dogs, whereas a delay of 8 days after 700 cGy resulted in virtually uniform graft failure. The time courses of acute GVHD (aGVHD) and rates of granulocyte recovery in engrafting dogs were comparable among dogs regardless of the lengths of delay. In other studies, we showed that most dogs not given HCT survived 700 cGy TBI with intensive supportive care, whereas those given 800 cGy TBI and higher died with marrow aplasia. Thus, DLA-haploidentical HCT was successful even when carried out 4, 8, or 10 days after TBI at or above radiation exposures where dogs survived with intensive care alone.

FGFR1/PI3K/AKT signaling pathway is a novel target for antiangiogenic effects of the cancer drug fumagillin (TNP-470).

Fibroblast growth factor-1 (FGF1), a prototypic member of the FGF family, is a potent angiogenic factor. Although FGF-stimulated angiogenesis has been extensively studied, the molecular mechanisms regulating FGF1-induced angiogenesis are poorly understood in vivo. Fumagillin, an antiangiogenic fungal metabolite, has the ability to inhibit FGF-stimulated angiogenesis in the chicken chorioallantoic membrane (CAM). In the current study, chicken CAMs were transfected with a signal peptide-containing version of the FGF1 gene construct (sp-FGF1). Transfected CAMs were then analyzed in the presence and absence of fumagillin treatment with respect to the mRNA expression levels and protein activity of the FGF1 receptor protein (FGFR1), phosphatidylinositol 3-kinase (PI3K), and its immediate downstream target, AKT-1 (protein kinase B). Treatment of sp-FGF1-transfected CAMs with fumagillin showed downregulation for both PI3K and AKT-1 proteins in mRNA expression and protein activity. In contrast, no major alterations in FGFR1 mRNA expression level were observed. Similar patterns of mRNA expression for the above three proteins were observed when the CAMs were treated with recombinant FGF1 protein in place of sp-FGF1 gene transfection. Investigation using biotin-labeled fumagillin showed that only the FGF1 receptor protein containing the cytoplasmic domain demonstrated binding to fumagillin. Furthermore, we demonstrated endothelial-specificity of the proposed antiangiogenic signaling cascade using an in vitro system. Based on these findings, we conclude that the binding of fumagillin to the cytoplasmic domain of the FGF1 receptor inhibited FGF1-stimulated angiogenesis both in vitro and in vivo.

Urinary levels of matrix metalloproteinase 9 and 2 and tissue inhibitor of matrix metalloproteinase in patients with coronary artery disease.

OBJECTIVES: To evaluate the feasibility of an assay for urinary levels of matrix metalloproteinases (MMPs) and the potential usefulness of urinary MMPs as a marker of coronary atherosclerosis or acute coronary syndromes (ACS). METHODS AND RESULTS: We measured urine and plasma MMP-9, MMP-2 and urine tissue inhibitor of metalloproteinase (TIMP-1) in patients with ACS (n=27), patients with coronary artery disease (CAD), but no clinical instability (n=47) and a group of healthy volunteers (n=15) who were <35 years of age, had no risk factors for CAD and did not undergo angiography. Compared with volunteers, patients with ACS and CAD had higher urine MMP-9, urine TIMP-1, plasma MMP-9 and plasma MMP-2 levels, but these did not differ between those with CAD and ACS. Using the volunteers to roughly establish an upper limit of normal, 84% of the urine TIMP-1 values and 95% of the urine MMP-9 values were abnormally elevated among those with CAD and ACS. CONCLUSIONS: Urine MMP-9 and TIMP-1 levels are elevated in patients with CAD and ACS compared with healthy volunteers. A high percent of patients with CAD or ACS had elevated urine values of MMP-9 and TIMP-1 suggesting these variables might be a useful marker of atherosclerotic disease.

Transcription factor Ets-1 regulates fibroblast growth factor-1-mediated angiogenesis in vivo: role of Ets-1 in the regulation of the PI3K/AKT/MMP-1 pathway.

We previously demonstrated that a modified secreted form of fibroblast growth factor 1 (FGF-1), a prototypic member of the FGF family, has the ability to stimulate angiogenesis in an in vivo model of angiogenesis, the so-called chick chorioallantoic membrane assay or CAM. We recently defined the importance of the phosphatidylinositol 3-kinase/AKT pathway in FGF-1-mediated angiogenesis in this model using specific pharmacological inhibitors. In our continuing efforts to define the molecular signaling pathway regulating FGF-1-induced angiogenesis in vivo, we utilized a transcription factor activity assay and identified transcription factor Ets-1 as a critical effector of FGF-1-induced angiogenesis. Both activity and mRNA expression levels of the Ets-1 molecule were increased in response to FGF-1 overexpression in CAMs, as documented by electrophoretic mobility shift assay (gel shift) and reverse transcription real-time PCR techniques, respectively. Furthermore, the delivery of Ets-1 antisense (AS) into CAM tissues effectively reduced angiogenesis in the CAM assay. In addition, both Ets-1 AS-treated chicken CAMs and cultured endothelial cells exhibited a reduction in matrix metalloproteinase 1 gene expression levels. The Ets-1 AS-treated endothelial cells also demonstrated a reduction in migration. These data suggest that Ets-1 activation is a requisite for FGF-1-mediated angiogenesis in vivo. Therefore, Ets-1 might be a potential target for the generation of inhibitor drugs for the treatment of FGF-dependent pathological angiogenesis such as metastatic tumors, rheumatoid arthritis and diabetic retinopathy.

Fibroblast growth factors, fibroblast growth factor receptors, diseases, and drugs.

Maintenance of endothelial cells (ECs), the building blocks of the vascular tree, is a presumed function of fibroblast growth factors (FGFs). In particular, the two prototypic members of FGF family, namely FGF1 and FGF2, due to their potent mitogenic and pro-migratory activities, have the ability to induce metabolic and phenotypic changes in ECs that are required to stimulate angiogenesis. In addition to FGF1 and FGF2, 23 other members of the FGF family have since been identified and characterized and they are reviewed in relation to their disease pathology. Particular emphasis is given to the biology of the FGFs and FGFRs on how they mediate the onset of angiogenesis. The focus of the present review is to survey what is known about the role of the currently identified FGFs and their four high affinity tyrosine kinase receptors in diseases and the angiogenesis-targeted drugs currently in clinical trials. Some new and promising patented drugs that target the angiogenic pathway are discussed. Examination of the currently patented drugs may identify more potent and specific regulators of FGF/FGFR signaling system for treatment of tumor angiogenesis in clinical settings. Additionally, novel drug development strategies are highlighted and reviewed.

Phosphatidylinositide 3-kinase is important in late-stage fibroblast growth factor-1-mediated angiogenesis in vivo.

We previously reported that overexpression of a secreted version of fibroblast growth factor-1 (sp-FGF-1) has the ability to induce angiogenesis in the chicken chorioallantoic membrane (CAM). In our current study, we examine the effects of sp-FGF-1 through a time course analysis of angiogenesis in the chicken CAM on days 3, 4, and 5 after gene transfection. Significant angiogenesis was observed on days 4 and 5 after gene transfection in the CAM assay. To evaluate the role of phosphatidylinositide 3-kinase (PI3K) signaling in sp-FGF-1-induced angiogenesis, we analyzed mRNA expression levels of PI3K and protein activity through its immediate downstream target, AKT-1. We found upregulation of both PI3K and AKT mRNA expression levels in day 5 sp-FGF-1 versus day 5 vector control-transfected CAMs. Furthermore, by blocking PI3K phosphorylation using the specific inhibitor, LY294002, we found that downstream phosphorylation of AKT-1 was inhibited. More importantly, the blockade of the PI3K pathway via LY294002 in sp-FGF-1-transfected CAMs significantly inhibited angiogenesis. These results further elucidate the molecular mechanisms of the sp-FGF-1 signaling pathway and it underscores the importance of PI3K signaling in FGF-1-stimulated angiogenesis in vivo. It also provides a basis for the role of sp-FGF-1 in the development of therapeutic treatments to combat vascular insufficiencies and angiogenesis-dependent cancers.

Role of AKT/PKB signaling in fibroblast growth factor-1 (FGF-1)-induced angiogenesis in the chicken chorioallantoic membrane (CAM).

Transfection of chicken chorioallantoic membranes (CAMs) with a chimeric secreted version of fibroblast growth factor-1 (sp-FGF-1) gene construct leads to a significant increase in vascularization. Though FGF-stimulated angiogenesis has been extensively studied, the molecular mechanisms regulating FGF-1-induced angiogenesis are poorly understood in vivo. This study was designed to investigate the role of the AKT (PKB) kinase signaling pathway in mediating sp-FGF-1-induced angiogenesis in the chicken CAM. The involvement of the AKT pathway was demonstrated by up-regulation of AKT1 mRNA expression in sp-FGF-1 compared to vector alone control transfected CAMs as demonstrated by real-time RT-PCR. Western analysis using an antibody specific to the activated AKT (phosphorylated AKT), demonstrated an increase in AKT activity in sp-FGF-1 compared to vector control transfected CAMs. More importantly, the AKT inhibitor ML-9 significantly reduced sp-FGF-1-induced angiogenesis in CAMs. These results indicate that AKT signaling plays a role in FGF-1-stimulated angiogenesis in vivo and the AKT pathway may serve as a therapeutic target for angiogenesis-associated diseases.

Cell-based and direct gene transfer-induced angiogenesis via a secreted chimeric fibroblast growth factor-1 (sp-FGF-1) in the chick chorioallantoic membrane (CAM).

Fibroblast growth factor-1 (FGF-1) is a potent angiogenic factor; its structure lacks a signal peptide for secretion. We previously reported that the overexpression of a secreted version of FGF-1 (sp-FGF-1) in microvascular endothelial cells (ECs) enhances cell migration [Partridge et al. J Cell Biochem 2000; 78(3): 487]. In the current study, we have examined the angiogenic effects of sp-FGF-1 in chicken chorioallantoic membranes (CAMs). Two methods of examining the effects of sp-FGF-1 in CAMs were used: cell-mediated transfection via bovine ECs and direct gene transfection. In the cell-mediated gene transfection, those eggs that were implanted with a gelatin sponge seeded with ECs stably transfected to over-express sp-FGF-1 protein showed a significant increase in angiogenesis inside the sponge when compared to eggs treated with vector control-transfected ECs. In the direct gene transfer, eggs received sp-FGF-1 showed a significant increase in vascularization when compared to eggs received vector alone plasmids. These CAM models are useful both for studying molecular mechanisms of angiogenesis and for developing better gene therapy strategies.

Eph B4 receptor signaling mediates endothelial cell migration and proliferation via the phosphatidylinositol 3-kinase pathway.

The goals of this study were 2-fold: 1) to determine whether stimulation of Eph B4 receptors promotes microvascular endothelial cell migration and/or proliferation, and 2) to elucidate signaling pathways involved in these responses. The human endothelial cells used possessed abundant Eph B4 receptors with no endogenous ephrin B2 expression. Stimulation of these receptors with ephrin B2/Fc chimera resulted in dose- and time-dependent phosphorylation of Akt. These responses were inhibited by LY294002 and ML-9, blockers of phosphatidylinositol 3-kinase (PI3K) and Akt, respectively. Eph B4 receptor activation increased proliferation by 38%, which was prevented by prior blockade with LY294002, ML-9, and inhibitors of protein kinase G (KT5823) and MEK (PD98059). Nitrite levels increased over 170% after Eph B4 stimulation, indicating increased nitric oxide production. Signaling of endothelial cell proliferation appears to be mediated by a PI3K/Akt/endothelial nitric-oxide synthase/protein kinase G/mitogen-activated protein kinase cascade. Stimulation with ephrin B2 also increased migration by 63% versus controls. This effect was inhibited by blockade with PP2 (Src inhibitor), LY294002 or ML-9 but was unaffected by the PKG and MEK blockers. Eph B4 receptor stimulation increased activation of both matrix metalloproteinase-2 and -9. The results from these studies indicate that Eph B4 stimulates migration and proliferation and may play a role in angiogenesis.