Adriana Karina Chávez-Rueda

Prolactin Levels Correlate with Abnormal B Cell Maturation in MRL and MRL/lpr Mouse Models of Systemic Lupus Erythematosus-Like Disease

Prolactin (PRL) plays an important role in modulating the immune response. In B cells, PRL enhances antibody production, including antibodies with self-specificity. In this study, our aims were to determine the level of PRL receptor expression during bone-marrow B-cell development and to assess whether the presence of high PRL serum concentrations influences absolute numbers of developing populations and disease outcome in lupus-prone murine models. We observed that the PRL-receptor is expressed in early bone-marrow B-cell; the expression in lupus-prone mice, which had the highest level of expression in pro-B cells and immature cells, differed from that in wild-type mice. These expression levels did not significantly change in response to hyperprolactinemia; however, populations of pro-B and immature cells from lupus-prone strains showed a decrease in the absolute numbers of cells with high PRL-receptor expression in response to PRL. Because immature self-reactive B cells are constantly being eliminated, we assessed the expression of survival factor BIRC5, which is more highly expressed in both pro-B and immature B-cells in response to PRL and correlates with the onset of disease. These results identify an important role of PRL in the early stages of the B-cell maturation process: PRL may promote the survival of self-reactive clones.

Increased levels of prolactin receptor expression correlate with the early onset of lupus symptoms and increased numbers of transitional-1 B cells after prolactin treatment

BackgroundProlactin is secreted from the pituitary gland and other organs, as well as by cells such as lymphocytes. Prolactin has an immunostimulatory effect and is associated with autoimmune diseases that are characterised by abnormal B cell activation, such as systemic lupus erythematosus (SLE). Our aim was to determine if different splenic B cell subsets express the prolactin receptor and if the presence of prolactin influences these B cell subsets and correlates with development of lupus.ResultsUsing real-time PCR and flow cytometry, we found that different subsets of immature (transitional) and mature (follicular, marginal zone) B cells express different levels of the prolactin receptor and are differentially affected by hyperprolactinaemia. We found that transitional B cells express the prolactin receptor at higher levels compared to mature B cells in C57BL/6 mice and the lupus-prone MRL/lpr and MRL mouse strains. Transitional-1 (T1) B cells showed a higher level of prolactin receptor expression in both MRL/lpr and MRL mice compared to C57BL/6 mice. Hyperprolactinaemia was induced using metoclopramide, which resulted in the development of early symptoms of SLE. We found that T1 B cells are the main targets of prolactin and that prolactin augments the absolute number of T1 B cells, which reflects the finding that this B cell subpopulation expresses the highest level of the prolactin receptor.ConclusionsWe found that all B cell subsets express the prolactin receptor but that transitional B cells showed the highest prolactin receptor expression levels. Hyperprolactinaemia in mice susceptible to lupus accelerated the disease and increased the absolute numbers of T1 and T3 B cells but not of mature B cells, suggesting a primary effect of prolactin on the early stages of B cell maturation in the spleen and a role of prolactin in B cell differentiation, contributing to SLE onset.

Peripheral blood lymphocytes from low-grade squamous intraepithelial lesions patients recognize vaccine antigens in the presence of activated dendritic cells, and produced high levels of CD8+IFNγ+T cells and low levels of IL-2 when induced to proliferate

BackgroundMost infections with human papillomavirus (HPV) are resolved without clinical intervention, but a minority evolves into chronic lesions of distinct grades, including cervical-uterine cancer. It is known that in most cases the immune system mediates elimination of HPV infection. However, the mechanism of immune evasion leading to HPV persistence and development of early cervical lesions is not fully understood. The aim of the present work was to evaluate the potential of peripheral blood leukocytes (PBL) from low-grade squamous intraepithelial lesions (LSIL) patients to be activated ex-vivo by vaccine antigens, the participation of cytotoxic lymphocytes and regulatory T cells, and to determine the secretion of Th1 and Th2 cytokines mediated by stimulation of T cell receptors.ResultsWe found that PBL from LSIL patients showed a significantly lower proliferation rate to vaccine antigens as compared to that of healthy donors, even though there was not a difference in the presence of antibodies to those antigens in sera from both groups. We did not find differences in either the frequency of CD4 + CD25 + FoxP3+ in PBL, or the levels of IL-4, IL-5 and IL-10 in plasma or conditioned media from PBL incubated with TcR agonists in vitro, between the two groups. However, we detected a lower production of IL-2 and a higher proportion of CD8 + IFNγ + cells in PBL from LSIL patients as compared with PBL from normal donors. We also observed that PBL from patients infected by HPV-16 and −18 were not able to proliferate in the presence of soluble HPV antigens added to the culture; however, a high level of proliferation was attained when these antigens were presented by activated dendritic cells.ConclusionsOur results suggest that the immunodeficiency reported in LSIL patients could be due to the inability of specific cytotoxic T lymphocytes that for some unknown reason are present but unable to mount a response when challenged with their antigens, probably related to an in situ IL-2 production deficiency.

Type Iii Interferons in Systemic Lupus Erythematosus: Association Between Interferon λ3, Disease Activity, and Anti-ro/ssa Antibodies

Objective The aim of this study was to assess associations between serum type III (&lgr;) interferons (IFN-&lgr;) and disease activity in systemic lupus erythematosus (SLE). Methods Serum levels of IFN-&lgr;1, IFN-&lgr;2, and IFN-&lgr;3 were measured in 93 SLE patients and 67 healthy individuals. The associations with overall disease activity, organ-specific damage, and SLE-related antibodies were assessed. Results Median IFN-&lgr;1 levels were 0 pg/mL (range, 0–510 pg/mL) and 0 pg/mL (0–171 pg/mL; P = 0.814) in SLE patients and control subjects, respectively. These figures were 0 pg/mL (0–28 pg/mL) and 0 pg/mL (0–43 pg/mL; P = 0.659) for IFN-&lgr;2, as well as 83 pg/mL (0–965 pg/mL) and 42 pg/mL (0–520 pg/mL; P = 0.002) for IFN-&lgr;3, respectively. According to the Systemic Lupus Erythematosus Disease Activity Index categories, IFN-&lgr;3 levels were 44 pg/mL (0–158 pg/mL) in quiescent, 117 pg/mL (0–344 pg/mL) in mild, 79 pg/mL (0–965 pg/mL) in moderate, and 78 pg/mL (0–329 pg/mL) in severe disease, with the highest levels found in patients with serosal or cutaneous involvement. In line with this, IFN-&lgr;3 levels were inversely correlated with C3 (&rgr; = −0.44; 95% confidence interval, −0.62 to −0.20; P = 0.0003) and C4 (&rgr; = −0.40; 95% confidence interval, −0.59 to −0.15; P = 0.0001) complement proteins. In addition, higher IFN-&lgr;3 levels were found in patients positive for anti-Ro/SSA antibodies than in those negative for that antibody (122 pg/mL [0–965 pg/mL] vs. 0 pg/mL [0–165 pg/mL]; P = 0.001). The concentration of IFN-&lgr;3 also was higher in patients receiving glucocorticoids (104 pg/mL [0–965 pg/mL] vs. 30 pg/mL [0–165 pg/mL]; P = 0.009), and a dose-related effect was observed. Conclusions Interferon &lgr;3, a subtype of type III IFNs, is associated with the extent of lupus activity, in particular with active serosal and cutaneous disease. This association could be mechanistically related to anti-Ro/SSA antibodies.OBJECTIVE The aim of this study was to assess associations between serum type III (λ) interferons (IFN-λ) and disease activity in systemic lupus erythematosus (SLE). METHODS Serum levels of IFN-λ1, IFN-λ2, and IFN-λ3 were measured in 93 SLE patients and 67 healthy individuals. The associations with overall disease activity, organ-specific damage, and SLE-related antibodies were assessed. RESULTS Median IFN-λ1 levels were 0 pg/mL (range, 0-510 pg/mL) and 0 pg/mL (0-171 pg/mL; P = 0.814) in SLE patients and control subjects, respectively. These figures were 0 pg/mL (0-28 pg/mL) and 0 pg/mL (0-43 pg/mL; P = 0.659) for IFN-λ2, as well as 83 pg/mL (0-965 pg/mL) and 42 pg/mL (0-520 pg/mL; P = 0.002) for IFN-λ3, respectively. According to the Systemic Lupus Erythematosus Disease Activity Index categories, IFN-λ3 levels were 44 pg/mL (0-158 pg/mL) in quiescent, 117 pg/mL (0-344 pg/mL) in mild, 79 pg/mL (0-965 pg/mL) in moderate, and 78 pg/mL (0-329 pg/mL) in severe disease, with the highest levels found in patients with serosal or cutaneous involvement. In line with this, IFN-λ3 levels were inversely correlated with C3 (ρ = -0.44; 95% confidence interval, -0.62 to -0.20; P = 0.0003) and C4 (ρ = -0.40; 95% confidence interval, -0.59 to -0.15; P = 0.0001) complement proteins. In addition, higher IFN-λ3 levels were found in patients positive for anti-Ro/SSA antibodies than in those negative for that antibody (122 pg/mL [0-965 pg/mL] vs. 0 pg/mL [0-165 pg/mL]; P = 0.001). The concentration of IFN-λ3 also was higher in patients receiving glucocorticoids (104 pg/mL [0-965 pg/mL] vs. 30 pg/mL [0-165 pg/mL]; P = 0.009), and a dose-related effect was observed. CONCLUSIONS Interferon λ3, a subtype of type III IFNs, is associated with the extent of lupus activity, in particular with active serosal and cutaneous disease. This association could be mechanistically related to anti-Ro/SSA antibodies.

Prolactin Rescues Immature B-Cells from Apoptosis Induced by B-Cell Receptor Cross-Linking.

Prolactin has an immunomodulatory effect and has been associated with B-cell-triggered autoimmune diseases, such as systemic lupus erythematosus (SLE). In mice that develop SLE, the PRL receptor is expressed in early bone marrow B-cells, and increased levels of PRL hasten disease manifestations, which are correlated with a reduction in the absolute number of immature B-cells. The aim of this work was to determine the effect of PRL in an in vitro system of B-cell tolerance using WEHI-231 cells and immature B-cells from lupus prone MRL/lpr mice. WEHI-231 cells express the long isoform of the PRL receptor, and PRL rescued the cells from cell death by decreasing the apoptosis induced by the cross-linking of the B-cell antigen receptor (BCR) as measured by Annexin V and active caspase-3. This decrease in apoptosis may have been due to the PRL and receptor interaction, which increased the relative expression of antiapoptotic Bcl-xL and decreased the relative expression of proapoptotic Bad. In immature B-cells from MRL/lpr mice, PRL increased the viability and decreased the apoptosis induced by the cross-linking of BCR, which may favor the maturation of self-reactive B-cells and contribute to the onset of disease.

Helicobacter pylori CagA Suppresses Apoptosis through Activation of AKT in a Nontransformed Epithelial Cell Model of Glandular Acini Formation

H. pylori infection is the most important environmental risk to develop gastric cancer, mainly through its virulence factor CagA. In vitro models of CagA function have demonstrated a phosphoprotein activity targeting multiple cellular signaling pathways, while cagA transgenic mice develop carcinomas of the gastrointestinal tract, supporting oncogenic functions. However, it is still not completely clear how CagA alters cellular processes associated with carcinogenic events. In this study, we evaluated the capacity of H. pylori CagA positive and negative strains to alter nontransformed MCF-10A glandular acini formation. We found that CagA positive strains inhibited lumen formation arguing for an evasion of apoptosis activity of central acini cells. In agreement, CagA positive strains induced a cell survival activity that correlated with phosphorylation of AKT and of proapoptotic proteins BIM and BAD. Anoikis is a specific type of apoptosis characterized by AKT and BIM activation and it is the mechanism responsible for lumen formation of MCF-10A acini in vitro and mammary glands in vivo. Anoikis resistance is also a common mechanism of invading tumor cells. Our data support that CagA positive strains signaling function targets the AKT and BIM signaling pathway and this could contribute to its oncogenic activity through anoikis evasion.

IL-17-differentiated macrophages secrete pro-inflammatory cytokines in response to oxidized low-density lipoprotein

BackgroundCytokines and macrophages play a central role in the development of atherosclerosis. Interleukin (IL)-17 is a pro-inflammatory cytokine with differential effects on innate immune cells. We investigated the effects of IL-17 on macrophage differentiation and foam cell formation and activation in response to oxidized low-density lipoprotein (oxLDL).MethodsHuman monocytes were treated with IL-17 to induce macrophage differentiation. As controls, human monocytes were differentiated into M1 macrophages (M1) or M2 macrophages (M2). Subsequently, we analyzed the expression levels of markers such as CD80, CD36 and Toll-like receptors (TLRs) as well as foam cell formation and cytokines in M1, M2 and macrophages differentiated with IL-17 with or without oxLDL.ResultsThe expression of M1 or M2 markers or cytokines was not induced in macrophages differentiated with IL-17. Macrophages differentiated with IL-17 formed few foam cells, with an average proportion of 20%, and expressed 3 times as much TLR2 and 3.8 times as much TLR4 as M0 macrophages. Additionally, macrophages differentiated with IL-17 acquired inflammatory capacity in response to oxLDL through the expression of specific markers, such as CD80, which increased 18-times compared with macrophages differentiated with IL-17 alone, and secreted 1.3 times less tumor necrosis factor (TNF)-α than M1. Additionally, oxLDL increased the levels of CD80, CD86 and IL-6 by 5.7, 2.8 and 1.4 times in M1 compared with M1 in the absence of oxLDL. In M2, oxLDL induced increases in the secretion of IL-6 and TNF-α that were 1.9 times and 1.2 times smaller, respectively, than those observed in M1.ConclusionOur study demonstrates that differentiation of macrophages with IL-17 does not induce the expression of markers or cytokines characteristic of M1 or M2 and these macrophages form few foam cells; however, the expression of TLR is increased. Moreover, these macrophages acquire the inflammatory capacity as evidenced by the expression of costimulatory molecules and secretion of pro-inflammatory cytokines in response to oxLDL. These findings suggest that the activation of macrophages differentiated with IL-17 by oxLDL contributes to the inflammatory process of atherosclerosis.

Effect of Native and Minimally Modified Low-density Lipoprotein on the Activation of Monocyte Subsets

BACKGROUND In atherosclerosis, monocytes are essential and secrete pro-inflammatory cytokines in response to modified low-density lipoprotein (LDL). Human CD14++CD16-, CD14++CD16+ and CD14+CD16++ monocytes produce different cytokines. The objective of this research was to determine the number of monocyte subsets positives to cytokines in response to native (nLDL) and minimally modified LDL (mmLDL). METHODS Human monocytes from healthy individuals were purified by negative selection and were stimulated with nLDL, mmLDL or LPS. Subsequently, human total monocytes were incubated with monoclonal antibodies specific for CD14 or both CD14 and CD16 to characterize total monocytes and monocyte subsets and with antibodies specific to anti-tumor necrosis factor (TNF)-α, anti-interleukin (IL)-6 and anti-IL-10. The number of cells positive for cytokines was determined and cells cultured with nLDL, mmLDL and LPS were compared with cells cultured only with culture medium. RESULTS We found that nLDL does not induce in the total monocyte population or in the three monocyte subsets positives to cytokines. MmLDL induced in total monocytes positives to TNF-α and IL-6 as well as in both CD14++CD16+ and CD14+CD16++ and in CD14++CD16+ monocytes, respectively. Moreover, total monocytes and the three monocyte subsets expressed few amounts of cells positives to IL-10 in response to mmLDL. CONCLUSION Our study demonstrated that nLDL did not induce cells positives to cytokines and that the CD14++CD16+ and CD14+CD16++ monocyte subsets could be the main sources of TNF-α and IL-6, respectively, in response to mmLDL, which promotes the development and progression of atherosclerotic plaque.