NEDD9 Is a Novel and Modifiable Mediator of Platelet-Endothelial Adhesion in the Pulmonary Circulation.

Rationale: Data on the molecular mechanisms that regulate platelet-pulmonary endothelial adhesion under conditions of hypoxia are lacking, but may have important therapeutic implications. Objectives: To identify a hypoxia-sensitive, modifiable mediator of platelet-pulmonary artery endothelial cell adhesion and thrombotic remodeling. Methods: Network medicine was used to profile protein-protein interactions in hypoxia-treated human pulmonary artery endothelial cells. Data from liquid chromatography-mass spectrometry and microscale thermophoresis informed the development of a novel antibody (Ab) to inhibit platelet-endothelial adhesion, which was tested in cells from patients with chronic thromboembolic pulmonary hypertension (CTEPH) and three animal models in vivo. Measurements and Main Results: The protein NEDD9 was identified in the hypoxia thrombosome network in silico. Compared with normoxia, hypoxia (0.2% O2) for 24 hours increased HIF-1α (hypoxia-inducible factor-1α)-dependent NEDD9 upregulation in vitro. Increased NEDD9 was localized to the plasma-membrane surface of cells from control donors and patients with CTEPH. In endarterectomy specimens, NEDD9 colocalized with the platelet surface adhesion molecule P-selectin. Our custom-made anti-NEDD9 Ab targeted the NEDD9-P-selectin interaction and inhibited the adhesion of activated platelets to pulmonary artery endothelial cells from control donors in vitro and from patients with CTEPH ex vivo. Compared with control mice, platelet-pulmonary endothelial aggregates and pulmonary hypertension induced by ADP were decreased in NEDD9-/- mice or wild-type mice treated with the anti-NEDD9 Ab, which also decreased chronic pulmonary thromboembolic remodeling in vivo. Conclusions: The NEDD9-P-selectin protein-protein interaction is a modifiable target with which to inhibit platelet-pulmonary endothelial adhesion and thromboembolic vascular remodeling, with potential therapeutic implications for patients with disorders of increased hypoxia signaling pathways, including CTEPH.

NEDD9 targets COL3A1 to promote endothelial fibrosis and pulmonary arterial hypertension.

Germline mutations involving small mothers against decapentaplegic-transforming growth factor-ß (SMAD-TGF-ß) signaling are an important but rare cause of pulmonary arterial hypertension (PAH), which is a disease characterized, in part, by vascular fibrosis and hyperaldosteronism (ALDO). We developed and analyzed a fibrosis protein-protein network (fibrosome) in silico, which predicted that the SMAD3 target neural precursor cell expressed developmentally down-regulated 9 (NEDD9) is a critical ALDO-regulated node underpinning pathogenic vascular fibrosis. Bioinformatics and microscale thermophoresis demonstrated that oxidation of Cys18 in the SMAD3 docking region of NEDD9 impairs SMAD3-NEDD9 protein-protein interactions in vitro. This effect was reproduced by ALDO-induced oxidant stress in cultured human pulmonary artery endothelial cells (HPAECs), resulting in impaired NEDD9 proteolytic degradation, increased NEDD9 complex formation with Nk2 homeobox 5 (NKX2-5), and increased NKX2-5 binding to COL3A1 Up-regulation of NEDD9-dependent collagen III expression corresponded to changes in cell stiffness measured by atomic force microscopy. HPAEC-derived exosomal signaling targeted NEDD9 to increase collagen I/III expression in human pulmonary artery smooth muscle cells, identifying a second endothelial mechanism regulating vascular fibrosis. ALDO-NEDD9 signaling was not affected by treatment with a TGF-ß ligand trap and, thus, was not contingent on TGF-ß signaling. Colocalization of NEDD9 with collagen III in HPAECs was observed in fibrotic pulmonary arterioles from PAH patients. Furthermore, NEDD9 ablation or inhibition prevented fibrotic vascular remodeling and pulmonary hypertension in animal models of PAH in vivo. These data identify a critical TGF-ß-independent posttranslational modification that impairs SMAD3-NEDD9 binding in HPAECs to modulate vascular fibrosis and promote PAH.

Up-regulation of the mammalian target of rapamycin complex 1 subunit Raptor by aldosterone induces abnormal pulmonary artery smooth muscle cell survival patterns to promote pulmonary arterial hypertension.

Activation of the mammalian target of rapamycin complex 1 (mTORC1) subunit Raptor induces cell growth and is a downstream target of Akt. Elevated levels of aldosterone activate Akt, and, in pulmonary arterial hypertension (PAH), correlate with pulmonary arteriole thickening, which suggests that mTORC1 regulation by aldosterone may mediate adverse pulmonary vascular remodeling. We hypothesized that aldosterone-Raptor signaling induces abnormal pulmonary artery smooth muscle cell (PASMC) survival patterns to promote PAH. Remodeled pulmonary arterioles from SU-5416/hypoxia-PAH rats and monocrotaline-PAH rats with hyperaldosteronism expressed increased levels of the Raptor target, p70S6K, which provided a basis for investigating aldosterone-Raptor signaling in human PASMCs. Aldosterone (10(-9) to 10(-7) M) increased Akt/mTOR/Raptor to activate p70S6K and increase proliferation, viability, and apoptosis resistance in PASMCs. In PASMCs transfected with Raptor-small interfering RNA or treated with spironolactone/eplerenone, aldosterone or pulmonary arterial plasma from patients with PAH failed to increase p70S6K activation or to induce cell survival in vitro Optimal inhibition of pulmonary arteriole Raptor was achieved by treatment with Staramine-monomethoxy polyethylene glycol that was formulated with Raptor-small interfering RNA plus spironolactone in vivo, which decreased arteriole muscularization and pulmonary hypertension in 2 experimental animal models of PAH in vivo Up-regulation of mTORC1 by aldosterone is a critical pathobiologic mechanism that controls PASMC survival to promote hypertrophic vascular remodeling and PAH.-Aghamohammadzadeh, R., Zhang, Y.-Y., Stephens, T. E., Arons, E., Zaman, P., Polach, K. J., Matar, M., Yung, L.-M., Yu, P. B., Bowman, F. P., Opotowsky, A. R., Waxman, A. B., Loscalzo, J., Leopold, J. A., Maron, B. A. Up-regulation of the mammalian target of rapamycin complex 1 subunit Raptor by aldosterone induces abnormal pulmonary artery smooth muscle cell survival patterns to promote pulmonary arterial hypertension.

A mutant prion protein sensitizes neurons to glutamate-induced excitotoxicity.

Growing evidence suggests that a physiological activity of the cellular prion protein (PrP(C)) plays a crucial role in several neurodegenerative disorders, including prion and Alzheimer's diseases. However, how the functional activity of PrP(C) is subverted to deliver neurotoxic signals remains uncertain. Transgenic (Tg) mice expressing PrP with a deletion of residues 105-125 in the central region (referred to as ΔCR PrP) provide important insights into this problem. Tg(ΔCR) mice exhibit neonatal lethality and massive degeneration of cerebellar granule neurons, a phenotype that is dose dependently suppressed by the presence of wild-type PrP. When expressed in cultured cells, ΔCR PrP induces large, ionic currents that can be detected by patch-clamping techniques. Here, we tested the hypothesis that abnormal ion channel activity underlies the neuronal death seen in Tg(ΔCR) mice. We find that ΔCR PrP induces abnormal ionic currents in neurons in culture and in cerebellar slices and that this activity sensitizes the neurons to glutamate-induced, calcium-mediated death. In combination with ultrastructural and biochemical analyses, these results demonstrate a role for glutamate-induced excitotoxicity in PrP-mediated neurodegeneration. A similar mechanism may operate in other neurodegenerative disorders attributable to toxic, ß-rich oligomers that bind to PrP(C).

The N-terminal, polybasic region of PrP(C) dictates the efficiency of prion propagation by binding to PrP(Sc).

Prion propagation involves a templating reaction in which the infectious form of the prion protein (PrP(Sc)) binds to the cellular form (PrP(C)), generating additional molecules of PrP(Sc). While several regions of the PrP(C) molecule have been suggested to play a role in PrP(Sc) formation based on in vitro studies, the contribution of these regions in vivo is unclear. Here, we report that mice expressing PrP deleted for a short, polybasic region at the N terminus (residues 23-31) display a dramatically reduced susceptibility to prion infection and accumulate greatly reduced levels of PrP(Sc). These results, in combination with biochemical data, demonstrate that residues 23-31 represent a critical site on PrP(C) that binds to PrP(Sc) and is essential for efficient prion propagation. It may be possible to specifically target this region for treatment of prion diseases as well as other neurodegenerative disorders due to ß-sheet-rich oligomers that bind to PrP(C).

Highly active antiretroviral therapy does not completely suppress HIV in semen of sexually active HIV-infected men who have sex with men.

OBJECTIVE: Although HAART can suppress genital shedding and sexual transmission of HIV, men who have sex with men (MSM) have experienced a resurgent HIV epidemic in the HAART era. Many HIV-infected MSM continue to engage in unsafe sex, and sexually transmitted infections (STIs) or other factors may promote genital HIV shedding and transmission in this population despite HAART. In this study, we determined the prevalence of seminal HIV shedding in HIV-infected MSM on stable HAART, and its relationship with a number of clinical, behavioral and biological variables. DESIGN: Sexually active HIV-infected men using HAART were recruited from an MSM health clinic to provide semen and blood samples. METHODS: HIV levels were assessed in paired semen and blood samples by PCR. Clinical and behavioral data were obtained from medical records and questionnaires. Herpes simplex virus 2 (HSV-2) serostatus, seminal HSV-2 DNA, and markers of genital inflammation were measured using standard laboratory methods. RESULTS: Overall, HIV-1 was detected in 18 of 101 (18%) blood and 30 of 101 (30%) semen samples. Of 83 men with undetectable HIV in blood plasma, 25% had HIV in semen with copy numbers ranging from 80 to 2560. Multivariate analysis identified STI/urethritis (P = 0.003), tumor necrosis factor α (P = 0.0003), and unprotected insertive anal sex with an HIV-infected partner (P = 0.007) as independent predictors of seminal HIV detection. CONCLUSION: STIs and genital inflammation can partially override the suppressive effect of HAART on seminal HIV shedding in sexually active HIV-infected MSM. Low seminal HIV titers could potentially pose a transmission risk in MSM, who are highly susceptible to HIV infection.

Safety analysis of the diaphragm in combination with lubricant or acidifying microbicide gels: effects on markers of inflammation and innate immunity in cervicovaginal fluid.

OBJECTIVE: Diaphragms are being considered for use with vaginal microbicide gels to provide enhanced protection against sexually transmitted pathogens. The purpose of this study was to determine whether use of a diaphragm with microbicide or placebo gel causes cervicovaginal inflammation or perturbations in cervicovaginal immune defense. METHOD OF STUDY: Eighty-one non-pregnant women were randomized into three groups and instructed to use Milex (CooperSurgical, Inc., Trumbull, CT, USA)diaphragms overnight for 14 days in combination with one of the two acid-buffering microbicide gels [ACIDFORM (Instead Inc., La Jolla, CA, USA) or BufferGel(trade mark) (BG; ReProtect Inc., Baltimore, Maryland)] or placebo gel (K-Y Jelly); Personal Products Inc., Raritan, NJ, USA). Cervicovaginal lavages (CVLs) were performed prior to study entry and on days 8 and 16. Nine soluble mediators of vaginal inflammation or immune defense were measured in CVLs by Bio-Plex or ELISA. RESULTS: Use of diaphragms with placebo or microbicide gel was not associated with increased levels of inflammation markers. Concentrations of secretory leukocyte protease inhibitor (SLPI) were markedly reduced in the BG group. CONCLUSION: Daily use of a diaphragm with placebo or acidifying microbicide gel did not cause cervicovaginal inflammation. However, diaphragm/BG use was associated with markedly reduced levels of SLPI, an important mediator of innate immune defense. Further studies are warranted to establish the safety of diaphragm/microbicide gel combinations.

Concentrations and significance of cytokines and other immunologic factors in semen of healthy fertile men.

BACKGROUND: The purpose of this study was to establish normal reference values for several immunologic factors in semen to provide a foundation for understanding their physiologic significance in health and disease. METHODS: Semen from 83 healthy, fertile men was assessed by Bio-Plex or enzyme-linked immunosorbent assay to determine quantities of immunoglobulin (Ig) isotypes, chemokines, cytokines and growth factors. We also enumerated polymorphonuclear granulocytes (PMN) by peroxidase staining to examine the association of inflammation with levels of these factors. RESULTS: High concentrations of IgG and IgA were detected in all samples. IgG concentrations were significantly higher than IgA concentrations (P < 0.0001). Likewise, two multifunctional growth factors, transforming growth factor-beta1 and interleukin (IL)-7, and three chemokines, stromal cell-derived factor-1alpha, monocyte chemotactic/chemoattractant protein-1 and IL-8, were present in high concentrations in all samples (medians >1000 pg/ml). Other soluble factors were detectable in low concentration (medians <150 pg/ml), either in a majority of samples [IL-1alpha and beta, IL-5, IL-6, IL-13, IL-17, regulated on activation normal T cell expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-1beta, interferon (IFN)-alpha and granulocyte colony-stimulating factor (CSF)], or in a minority of samples (MIP-1alpha, IL-2, IL-10, IL-12, TNF-alpha, IFN-gamma and granulocyte-macrophage-CSF). PMN counts significantly correlated with IL-1beta, IL-6, TNF-alpha, MIP-1alpha, MIP-1beta, IL-13 and IgA concentrations. CONCLUSIONS: The semen of healthy, fertile men contains a broad array of immunologic factors. These normative values can serve as a foundation for future studies on the role of these factors in infertility, genital tract infections and other pathologic conditions.

T-lymphocyte profile and total and virus-specific immunoglobulin concentrations in the cervix of HIV-1-infected women.

BACKGROUND: The mucosal lymphocyte population is the largest in the body, and the gastrointestinal compartment has been well characterized in HIV infection. Much less is known about the effects of HIV on the genital tract. OBJECTIVE: : To examine the T-lymphocyte phenotype and receptor repertoire as well as total and virus-specific immunoglobulin concentrations in the endocervix of HIV-infected women at different stages of infection as compared with uninfected women. PATIENTS AND METHODS: Participants were 12 seronegative women, 10 HIV-infected "slow progressors" not taking antiretroviral therapy, and 9 HIV-infected women whose antiretroviral therapy was failing. We used multiparameter flow cytometry to enumerate T-cell populations on cytobrush-obtained cervical specimens, the immunoscope technique to determine the T-cell receptor (TCR) repertoire, and quantitative enzyme-linked immunosorbent assays for antibody determinations on cervical secretions absorbed onto ophthalmic sponges. Nonparametric statistical analyses were performed. RESULTS: We found marked depletion of leukocytes and CD4 T lymphocytes in the endocervix of HIV-infected women as compared with uninfected women; this was significant at more advanced disease stages. Naive T cells were rare in the endocervix of all groups. Activation marker expression was higher in endocervical T lymphocytes than in peripheral blood among control and slow-progressing HIV-infected women but not in women failing therapy. Endocervical T lymphocytes showed highly restricted utilization of Vbeta TCR families. Unlike other mucosal sites, the cervix contained IgG as the predominant immunoglobulin isotype. HIV-IgG was detected in the cervix of most HIV-infected women and in blood of all infected women. CONCLUSIONS: HIV infection induces substantial changes in the immune profile of the female genital tract. Further study of the implications of these findings for HIV acquisition and transmission is needed.

Comparison of ophthalmic sponges for measurements of immune markers from cervical secretions.

Measurements of cervical immunity are important for evaluating immune responses to infections of the cervix and to vaccines for preventing those infections. Three ophthalmic sponges, Weck-Cel, Ultracell, and Merocel, were loaded in vitro with interleukin-1 beta (IL-1 beta), IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-15, IL-18, gamma interferon (IFN-gamma), granulocyte-macrophage colony-stimulating factor (GM-CSF), immunoglobulin A (IgA), or IgG, and sponges were extracted and evaluated for total recovery by enzyme-linked immunosorbent assay (ELISA). There was excellent (>75%) recovery for all immune markers from all three devices except for IL-6, which was poorly recovered (<60%) for all sponge types, IFN-gamma, which was poorly recovered from both Weck-Cel and Ultracell sponges but was completely recovered from Merocel sponges, and IL-4, which was poorly recovered from Weck-Cel sponges but was completely recovered from Ultracell or Merocel sponges. We then compared the absolute recovery of selected markers (IL-10, IL-12, IgG, and IgA) from cervical secretion specimens collected from women using each type of sponge. There were no significant differences in the recoveries of IL-10, IL-12, and IgG from cervical specimens collected by any type of ophthalmic sponge, but there was reduced IgA recovery from Merocel sponges. However, the variability in these measurements attributable to sponge types (1 to 3%) was much less than was attributable to individuals (45 to 72%), suggesting that differences in sponge type contribute only in a minor way to these measurements. We infer from our data that the three collection devices are adequate for the measurements of IL-1 beta, IL-2, IL-5, IL-12, IL-15, IL-18, and IgG. Merocel may be a better ophthalmic sponge for the collection of cervical secretions and measurements of IL-4, IL-8, IL-10, GM-CSF, and IFN-gamma, but our data from clinical specimens, not in vitro-loaded sponges, suggested the possibility of reduced recovery of IgA. These findings require confirmation.

Correlates of IL-10 and IL-12 concentrations in cervical secretions.

Interindividual variations in host immune responses to HPV infection are thought to be important determinants of viral persistence and progression to cervical intraepithelial neoplasia and cancer. However, few studies have measured local immune markers at the site of infection (e.g., the cervical mucosa). We sought to determine biologic correlates of IL-10 and IL-12 concentrations in cervical secretions. Cervical secretions were passively collected using a WeckCel sponge from 247 women participating in a natural history study of human papillomavirus infection as part of an immunologic ancillary study. IL-10 and IL-12 concentrations were determined using standard ELISA assays. In general, IL-10 and IL-12 levels were significantly intercorrelated (Pearson's correlation coefficient = 0.6) but had somewhat different determinants. Significant increases (P < 0.05) in IL-10 concentrations were observed for nonovulatory phases of the menstrual cycle, postmenopausal status, recent use of oral contraceptives (OC), low secretion volume, macrolevels of heme contamination, and high vaginal pH. Increasing IL-10 levels were also observed among smokers, women with increasing numbers of lifetime sex partners, and women who report having less frequent sex (less than once per week), however, these results were not statistically significant. Significantly higher IL-12 concentrations were observed among recent OC users, women with low secretion volume, and women with a high vaginal pH. There was a non-statistically significant observation of increasing IL-12 levels among nonsmokers, women with increasing numbers of lifetime and recent pregnancies, and increasing levels of heme contamination. We failed to observe a significant association between HPV and IL-10 or IL-12 levels in this crosssectional sample. Future analyses of cervical cytokine levels and HPV infection should control for the inherent variation of local cytokine levels due to hormonal influences, hemoglobin contamination, pH, and cervical secretion volume differences.

Mucosal immunity of the adolescent female genital tract.

This study sought to characterize mucosal immunity of the adolescent genital tract during the cycle and determine if adolescents have more suppressed immunoglobulin levels in the follicular phase than adults. Daily from cycle day 9 until ovulation, then every other day until menses, cervical secretions for IgA, IgG, and cytokines were collected via Weck-Cel sponge and serum for luteinizing hormone (LH), estradiol, and progesterone was obtained from three adolescent girls (mean age 16.8 years). Immunoglobulin and cytokine levels varied during the menstrual cycle, reaching their nadir around ovulation. Compared with 13 adults, adolescents had a greater drop in IgG in the follicular phase (mean beta-953 vs. -269 microg/mL/day, p = .045), but a similar rate of rise in IgG in the luteal phase (mean beta +118 vs. +100 microg/mL/day, p = .252). Rates of change in IgA did not differ between adolescents and adults for either phase. Although limited by the small sample size, these findings suggest that adolescents may be more sensitive to unopposed estrogen and warrant further investigation.