Ethel García-Latorre

Annexin A2 is involved in antiphospholipid antibody-mediated pathogenic effects in vitro and in vivo.

Antiphospholipid (aPL) antibodies recognize receptor-bound beta(2) glycoprotein I (beta(2)GPI) on target cells, and induce an intracellular signaling and a procoagulant/proinflammatory phenotype that leads to thrombosis. Evidence indicates that annexin A2 (A2), a receptor for tissue plasminogen activator and plasminogen, binds beta(2)GPI on target cells. However, whether A2 mediates pathogenic effects of aPL antibodies in vivo is unknown. In this work, we studied the effects of human aPL antibodies in A2-deficient (A2(-/-)) mice. A2(-/-) and A2(+/+) mice were injected with immunoglobulin G (IgG) isolated from either a patient with antiphospholipid syndrome (IgG-APS), a healthy control subject (IgG-normal human serum), a monoclonal anti-beta(2)GPI antibody (4C5), an anti-A2 monoclonal antibody, or monoclonal antibody of irrelevant specificity as control. We found that, after IgG-APS or 4C5 injections and vascular injury, mean thrombus size was significantly smaller and tissue factor activity was significantly less in A2(-/-) mice compared with A2(+/+) mice. The expression of vascular cell adhesion molecule-1 induced by IgG-APS or 4C5 in explanted A2(-/-) aorta was also significantly reduced compared with A2(+/+) mice. Interestingly, anti-A2 monoclonal antibody significantly decreased aPL-induced expression of intercellular cell adhesion molecule-1, E-selectin, and tissue factor activity on cultured endothelial cells. Together, these data indicate for the first time that A2 mediates the pathogenic effects of aPL antibodies in vivo and in vitro APS.

In Vivo Effects of an Inhibitor of Nuclear Factor-Kappa B on Thrombogenic Properties of Antiphospholipid Antibodies

Abstract:  It has been shown that endothelial cell (EC) activation and tissue factor (TF) upregulation in EC and monocytes by antiphospholipid antibodies (aPL Abs) leads to a prothrombotic state and involves translocation of nuclear factor‐kappa B (NF‐κB). Here we examined the effects of an NF‐κB inhibitor on aPL‐induced thrombosis, TF activity, and EC in vivo. We treated CD1 mice with IgG from a patient with antiphospholipid syndrome (IgG‐APS) or with control IgG (IgG‐NHS). The adhesion of leukocytes (number of white blood cells) to EC in cremaster muscle (as an indication of EC activation) as well as the size of an induced thrombus in the femoral vein of the mice were examined. Some mice in each group were infused with 10 μM MG132 (an inhibitor of NF‐κB). TF activity was determined using a chromogenic assay in homogenates of carotid arteries and in peritoneal cells of mice. In vivo, IgG‐APS increased significantly the number of white blood cells adhering to ECs (4.7 ± 2.2) when compared to control mice (1.5 ± 0.8), and these effects were significantly reduced when mice were pretreated with MG132 (0.8 ± 0.2). IgG‐APS increased significantly the thrombus size and MG132 inhibited that effect (93%). Treatment of the mice with IgG‐APS also induced significantly increased TF function in peritoneal cells and in homogenates of carotid arteries. Pretreatment of the mice with MG132 abrogated those effects significantly. Mice injected with IgG‐APS or with IgM‐APS with or without the inhibitor had medium–high titers of anticardiolipin antibodies in serum at the time of the surgical procedures. The data show that prothrombotic and proinflammatory properties of IgG‐APS and IgM‐APS are downregulated in vivo by an NF‐κB inhibitor. These findings may be important in designing new modalities of targeted therapies to treat thrombosis in patients with APS.

Quantitative and qualitative peritoneal immune profiles, T-cell apoptosis and oxidative stress-associated characteristics in women with minimal and mild endometriosis

Please cite this paper as: Mier‐Cabrera J, Jiménez‐Zamudio L, García‐Latorre E, Cruz‐Orozco O, Hernández‐Guerrero C. Quantitative and qualitative peritoneal immune profiles, T‐cell apoptosis and oxidative stress‐associated characteristics in women with minimal and mild endometriosis. BJOG 2011;118:6–16.

TiO 2 nanoparticles induce dysfunction and activation of human endothelial cells

Nanoparticles can reach the blood and cause inflammation, suggesting that nanoparticles-endothelial cells interactions may be pathogenically relevant. We evaluated the effect of titanium dioxide nanoparticles (TiO₂) on proliferation, death, and responses related with inflammatory processes such as monocytic adhesion and expression of adhesion molecules (E- and P-selectins, ICAM-1, VCAM-1, and PECAM-1) and with inflammatory molecules (tissue factor, angiotensin-II, VEGF, and oxidized LDL receptor-1) on human umbilical vein endothelial cells (HUVEC). We also evaluated the production of reactive oxygen species, nitric oxide production, and NF-κB pathway activation. Aggregates of TiO₂ of 300 nm or smaller and individual nanoparticles internalized into HUVEC inhibited proliferation strongly and induced apoptotic and necrotic death starting at 5 μg/cm². Besides, TiO₂ induced activation of HUVEC through an increase in adhesion and in expression of adhesion molecules and other molecules involved with the inflammatory process. These effects were associated with oxidative stress and NF-κB pathway activation. In conclusion, TiO₂ induced HUVEC activation, inhibition of cell proliferation with increased cell death, and oxidative stress.

Estrogens and Human Papilloma Virus Oncogenes Regulate Human Ether-à-go-go-1 Potassium Channel Expression

Ether-à-go-go-1 (Eag1) potassium channels are potential tools for detection and therapy of numerous cancers. Here, we show human Eag1 (hEag1) regulation by cancer-associated factors. We studied hEag1 gene expression and its regulation by estradiol, antiestrogens, and human papillomavirus (HPV) oncogenes (E6/E7). Primary cultures from normal placentas and cervical cancer tissues; tumor cell lines from cervix, choriocarcinoma, keratinocytes, and lung; and normal cell lines from vascular endothelium, keratinocytes, and lung were used. Reverse transcription-PCR (RT-PCR) experiments and Southern blot analysis showed Eag1 expression in all of the cancer cell types, normal trophoblasts, and vascular endothelium, in contrast to normal keratinocytes and lung cells. Estradiol and antiestrogens regulated Eag1 in a cell type-dependent manner. Real-time RT-PCR experiments in HeLa cells showed that Eag1 estrogenic regulation was strongly associated with the expression of estrogen receptor-alpha. Eag1 protein was detected by monoclonal antibodies in normal placenta and placental blood vessels. Patch-clamp recordings in normal trophoblasts treated with estradiol exhibited potassium currents resembling Eag1 channel activity. Eag1 gene expression in keratinocytes depended either on cellular immortalization or the presence of HPV oncogenes. Eag1 protein was found in keratinocytes transfected with E6/E7 HPV oncogenes. Cell proliferation of E6/E7 keratinocytes was decreased by Eag1 antibodies inhibiting channel activity and by the nonspecific Eag1 inhibitors imipramine and astemizole; the latter also increased apoptosis. Our results propose novel oncogenic mechanisms of estrogen/antiestrogen use and HPV infection. We also suggest Eag1 as an early indicator of cell proliferation leading to malignancies and a therapeutic target at early stages of cellular hyperproliferation.

TLRs and NODs mRNA expression pattern in healthy mouse eye.

Aims: To look for TLR and NOD mRNA expression in the healthy eye and in other immune privileged and non-immune privileged mouse organs. Methods: Semiquantitative RT-PCR was performed to look for TLR1–9 and NOD1 and NOD2 mRNA expressions in the whole eye, in the anterior (AP) and posterior (PP) portions of the eye, in corneal fibroblasts (CF) and in ovary, brain, testis, heart, lung, and spleen. Results: All the TLR mRNAs were expressed in the whole eye of Balb/c mice. NIH and C57BL/6 did not express TLR9 and TLR8, respectively. NIH expressed higher levels of TLR1, 2, 3, and 6 than the other strains. C57BL/6 expressed the lowest levels of all TLRs. TLR9, 5, and 4 were the less expressed in all strains. All TLRs were expressed in Balb/c PP and TLR1 was not expressed in AP. In NIH and Balb/c CF the majority of TLRs were overexpressed with LPS. In testis, expression of most TLRs was absent. Non-immune privileged organs expressed most of the TLRs. All the organs expressed NOD1 and NOD2. In PP NOD2 was not expressed. Conclusion: TLRs and NODs are expressed in the eye, and could have an important role in the innate immunity.

Characterization of brain inflammation during primary amoebic meningoencephalitis

Naegleria fowleri is a free-living amoeba and the etiologic agent of primary amoebic meningoencephalitis (PAM). Trophozoites reach the brain by penetrating the olfactory epithelium, and invasion of the olfactory bulbs results in an intense inflammatory reaction. The contribution of the inflammatory response to brain damage in experimental PAM has not been delineated. Using both optical and electron microscopy, we analyzed the morphologic changes in the brain parenchyma due to inflammation during experimental PAM. Several N. fowleri trophozoites were observed in the olfactory bulbs 72 h post-inoculation, and the number of amoebae increased rapidly over the next 24 h. Eosinophils and neutrophils surrounding the amoebae were then noted at later times during infection. Electron microscopic examination of the increased numbers of neutrophils and the interactions with trophozoites indicated an active attempt to eliminate the amoebae. The extent of inflammation increased over time, with a predominant neutrophil response indicating important signs of damage and necrosis of the parenchyma. These data suggest a probable role of inflammation in tissue damage. To test the former hypothesis, we used CD38-/- knockout mice with deficiencies in chemotaxis to compare the rate of mortality with the parental strain, C57BL/6J. The results showed that inflammation and mortality were delayed in the knockout mice. Based on these results, we suggest that the host inflammatory response and polymorphonuclear cell lysis contribute to a great extent to the central nervous system tissue damage.

C6 knock-out mice are protected from thrombophilia mediated by antiphospholipid antibodies

Background: Complement activation plays a role in pathogenesis of the antiphospholipid syndrome (APS), but the involvement of the C5b-9 membrane attack complex (MAC) is unknown. Here we studied the effects of human polyclonal antiphospholipid (aPL) antibodies on thrombosis and tissue factor (TF) up-regulation in C6 deficient (C6−/−) mice. Methods: C6−/− mice or the wild-type C3H/HeJ (C6+/+) mice were injected twice with IgG-APS (n = 2) or IgM-APS (n = 1) isolated from APS patients or with the corresponding control immunoglobulins (Igs) of normal human serum, (NHS) (IgG-NHS or IgM-NHS). Then, the sizes of induced thrombi in the femoral vein were determined 72 hours after the first injection. Tissue factor was determined in homogenates of carotid arteries and in peritoneal macrophages. Results: Thrombus sizes were significantly larger in C6+/+ treated with IgG-APS1 or with IgG-APS2 or with IgM-APS when compared with C6+/+ mice treated with IgG-NHS or with IgM-NHS, respectively. The sizes of thrombi were significantly smaller in the C6−/− mice injected with IgG-APS1, IgG-APS2 or IgM-APS (p < 0.001), compared to their C6+/+ counterparts showing an important abrogation of thrombus formation in mice lacking C6. The TF expression and activity in the C6−/− mice treated with IgG-APS or IgM-APS were diminished when compared to C3H/HeJ (C6+/+) mice treated with the same Igs. All mice injected with IgG-APS and IgM-APS had medium-high titers of anticardiolipin (aCL) and anti-β2glycoprotein I (aβ2GPI) antibodies. Conclusions: These data indicate that the C6 component of the complement system mediates aPL-thrombogenic effects, underscoring an important pathogenic mechanism and indicating the possibility of inhibiting complement to ameliorate APS-related manifestations.

Role of CD4+CD25+highFoxp3+CD62L+ regulatory T cells and invariant NKT cells in human allogeneic hematopoietic stem cell transplantation.

Allogeneic hematopoietic stem cell transplantation (HSCT) is the treatment of choice for some hematological diseases; however, graft-versus-host disease (GVHD) is still one of the most important and deleterious complications. Regulatory T cells and iNKT cells can decrease the incidence and severity of GVHD, while preserving the graft-versus-tumor response. In order to analyze the relationship between the transfused dose of these cells, the presence of GVHD and survival, 15 normal donors and 15 patients with hematological diseases who underwent allogeneic HSCT from HLA-identical siblings were studied. The mobilization and infused doses of valpha24-vbeta11(iNKT cells) lymphocytes and CD4+CD25+FoxP3+, CD4+CD25+FoxP3+CD62L+, regulatory T cells were analyzed. All patients were conditioned with busulfan and cyclophosphamide and received cyclosporine and methotrexate as GVHD prophylaxis. iNKT and FoxP3 cells were mobilized after G-CSF administration. Acute GVHD was present in 9 of 15 (60%) and cGVHD in 7 of 13 (54%) patients. Patients who received a dose <0.6 x 10(6)/kg of iNKT cells and >4 x 10(6)/kg of FoxP3 had better disease-free survival and overall survival. Individuals transfused with >1.1 x 10(6)/kg of FoxP3+ CD62L+ Treg cells had better overall survival. In conclusion, iNKT and Treg cells are mobilized with G-CSF in healthy donors and the dose of iNKT cells and FoxP3 and CD62L+ regulatory T cells is of clinical importance in human HSCT.

Clinical relevance of NK, NKT, and dendritic cell dose in patients receiving G-CSF-mobilized peripheral blood allogeneic stem cell transplantation

To analyze the relationship between the cellular composition of peripheral blood allografts and clinical outcome, we performed a prospective study in 45 adult patients who underwent allogeneic peripheral blood hematopoietic stem cell transplantation (HSCT) from a histocompatibility leukocyte antigen identical sibling donor for different hematological malignancies. The dose of CD34+, CD3+, CD4+, CD8+, and CD19+ lymphocytes, natural killer (NK) cells, natural killer T (NKT) cells, type 1 and type 2 dendritic cells (DC1 and DC2), as well as regulatory T (Treg) lymphocytes was analyzed. All patients were conditioned with busulphan and cyclophosphamide (BuCy2) ± VP-16 and received a short course of methotrexate and cyclosporin-A as graft-versus-host disease (GVHD) prophylaxis. Acute GVHD (aGVHD) was present in 9 of 43 (21%) patients, and chronic GVHD (cGVHD) developed in 18 of 39 (46%) patients. There was a significantly higher incidence of aGVHD in patients receiving more than 6×106/kg CD34+ cells. In univariate analysis, variables associated with better survival were as follows: a dose of less than 1.5×107/kg NKT cells and less than 1.7×106/kg DC2 for disease-free survival (DFS), and a dose of less than 3×107/kg NK cells, less than 1.5×107/kg NKT cells, less than 3×106/kg DC1, and less than 1.7×106/kg DC2 for overall survival (OS). In the Cox regression analysis, the dose of NKT cells was the only variable associated with better DFS, while the doses of NK, NKT, and CD34+ cells (less than 8×106/kg) were associated with better OS. In conclusion, different circulating cell populations, other than CD34+ cells, are also of relevance in predicting the clinical outcome after allogeneic peripheral blood HSCT.