Melatonin prevents dexamethasone‐induced testicular oxidative stress and germ cell apoptosis in golden hamster,Mesocricetus auratus

This study investigated the protective effect of melatonin on dexamethasone (Dex), an extensively used anti‐inflammatory and immunosuppressive synthetic glucocorticoid, induced testicular oxidative stress and germ cell apoptosis in golden hamster. Hamsters were randomly divided into four groups (n = 7): group I – control; group II – melatonin treated (10 mg kg^?1 day^?1); group III – Dex treated (7 mg kg^?1 day^?1) and group IV – combination of Dex and melatonin. All the injections were administered intraperitoneally for seven consecutive days. The histopathological changes, specific biochemical markers, including antioxidative enzymes, plasma melatonin level and the markers for germ cell apoptosis were evaluated. Dex administration decreased antioxidant enzyme activities (SOD, CAT, GSH‐P_X), plasma melatonin level and melatonin receptor (MT1) expression with a concomitant increase in lipid peroxidation (TBARS) and altered testicular histopathology which might culminate into increased germ cell apoptosis as evident from increased Bax/Bcl‐2 ratio and caspase‐3 expression. However, melatonin pre‐treatment enhanced enzyme activities for SOD, CAT, GSH‐P_X with a simultaneous decrease in Bax/Bcl‐2 ratio and caspase‐3 expression. Our findings clearly suggest that melatonin improved defence against Dex‐induced testicular oxidative stress and prevented germ cell apoptosis, suggesting a novel combination therapeutic approach for management of male reproductive health.     

Increased levels of interleukin-10 and IgG3 are hallmarks of Indian post-kala-azar dermal leishmaniasis

BACKGROUND: Post-kala-azar dermal leishmaniasis (PKDL), an established sequela of visceral leishmaniasis (VL), is proposed to facilitate anthroponotic transmission of VL, especially during interepidemic periods. Immunopathological mechanisms responsible for Indian PKDL are still poorly defined. METHODS: Our study attempted to characterize the immune profiles of patients with PKDL or VL relative to that of healthy control subjects by immunophenotyping, intracellular cytokine staining of peripheral blood mononuclear cells, and enzyme-linked immunosorbent assay for serum cytokines and immunoglobulin G (IgG) subclasses. RESULTS: Patients with PKDL had significantly raised percentages of peripheral CD3+CD8+ cells compared with control subjects, a difference that persisted after cure. Patients with PKDL showed an intact response to phytohemagglutinin, with the percentages of lymphocytes expressing interferon (IFN)-gamma, interleukin (IL)-2, IL-4, and IL-10 being comparable to those in control subjects. Patients with VL had decreased IFN-gamma and IL-2 expression, which was restored after cure, and increased IL-10 expression, which persisted after cure. In their response to Leishmania donovani antigen, patients with PKDL showed a 9.6-fold increase in the percentage of IL-10-expressing CD3+CD8+ lymphocytes compared with control subjects, and this percentage decreased with treatment. Patients with PKDL had raised levels of IgG3 and IgG1 (surrogate markers for IL-10), concomitant with increased serum levels of IL-10. CONCLUSIONS: IL-10-producing CD3+CD8+ lymphocytes are important protagonists in the immunopathogenesis of Indian PKDL.     

Th17 and non-Th17 interleukin-17-expressing cells in chronic lymphocytic leukemia: delineation, distribution, and clinical relevance

Background

The levels and clinical relevance of Th17 cells and other interleukin-17-producing cells have not been analyzed in chronic lymphocytic leukemia. The objective of this study was to quantify blood and tissue levels of Th17 and other interleukin-17-producing cells in patients with this disease and correlate blood levels with clinical outcome.

Design and Methods

Intracellular interleukin-17A was assessed in blood and splenic mononuclear cells from patients with chronic lymphocytic leukemia and healthy subjects using flow cytometry. Interleukin-17A-producing cells were analyzed in formalin-fixed, paraffin-embedded spleen and lymph node sections using immunohistochemistry and immunofluorescence.

Results

The absolute numbers of Th17 cells in peripheral blood mononuclear cells and the percentages of Th17 cells in spleen cell suspensions were higher in patients with chronic lymphocytic leukemia than in healthy subjects; in six out of eight paired chronic lymphocytic leukemia blood and spleen sample comparisons, Th17 cells were enriched in spleen suspensions. Circulating Th17 levels correlated with better prognostic markers and longer overall survival of the patients. Two “non-Th17” interleukin-17-expressing cells were identified in chronic lymphocytic leukemia spleens: proliferating cells of the granulocytic lineage and mature mast cells. Granulocytes and mast cells in normal spleens did not express interleukin-17. Conversely, both chronic lymphocytic leukemia and healthy lymph nodes contained similar numbers of interleukin-17+ mast cells as well as Th17 cells.

Conclusions

Th17 cells are elevated in chronic lymphocytic leukemia patients with better prognostic markers and correlate with longer survival. Furthermore, non-Th17 interleukin-17A-expressing cells exist in chronic lymphocytic leukemia spleens as maturing granulocytes and mature mast cells, suggesting that the microenvironmental milieu in leukemic spleens promotes the recruitment and/or expansion of Th17 and other IL-17-expressing cells. The pathophysiology of Th17 and non-Th17-interleukin-producing cells in chronic lymphocytic leukemia and their distributions and roles in this disease merit further study.     

Coupling of Proton Binding in Extracellular Domain to Channel Gating in Acid-Sensing Ion Channel

Protonation of several amino acid residues in the extracellular domain (ECD) of acid-sensing ion channel (ASIC) causes conformational changes that lead to opening of the channel. It is not clear how conformational changes in ECD are coupled to channel gating. Here, we show that the loop connecting β9 and α4 at the base of the thumb region of ECD interacts with post-TM1 to stabilize the channel in the closed state. Flexibility of these two regions is important for optimum gating of the channel. In ASIC1a, when Y71 (post-TM1) and W287 (β9–α4 loop) were mutated to cysteine, they formed disulfide bond in the closed state. Breaking of the disulfide bond by reducing agent dithiothreitol (DTT) or tris(2-carboxyethyl)phosphine (TCEP) potentiated the current significantly. Engineered cysteine G288C reacted with sulfhydryl-specific methanethiosulfonate ethyltrimethylammonium (MTSET) in the open state but not in closed/steady desensitized state, suggesting gating-associated conformational movement of this loop. We also identified a salt bridge between highly conserved R64 at TM1 and D432 at TM2 that is important for optimum gating. Based on our results and other published work, we propose that proton binding in ECD is followed by the displacement of the β9–α4 loop of the thumb, leading to the rotation of TM1. Conformational movement propagates to TM2 and the channel gate opens by the concomitant movement of TM2 and breaking of the salt bridge between R64 and D432.