IL-11 induces NLRP3 inflammasome activation in monocytes and inflammatory cell migration to the central nervous system.

The objective of this study is to examine IL-11-induced mechanisms of inflammatory cell migration to the central nervous system (CNS). We report that IL-11 is produced at highest frequency by myeloid cells among the peripheral blood mononuclear cell (PBMC) subsets. Patients with relapsing-remitting multiple sclerosis (RRMS) have an increased frequency of IL-11+ monocytes, IL-11+ and IL-11R+ CD4+ lymphocytes, and IL-11R+ neutrophils in comparison to matched healthy controls. IL-11+ and granulocyte-macrophage colony-stimulating factor (GM-CSF)+ monocytes, CD4+ lymphocytes, and neutrophils accumulate in the cerebrospinal fluid (CSF). The effect of IL-11 in-vitro stimulation, examined using single-cell RNA sequencing, revealed the highest number of differentially expressed genes in classical monocytes, including up-regulated NFKB1, NLRP3, and IL1B. All CD4+ cell subsets had increased expression of S100A8/9 alarmin genes involved in NLRP3 inflammasome activation. In IL-11R+-sorted cells from the CSF, classical and intermediate monocytes significantly up-regulated the expression of multiple NLRP3 inflammasome-related genes, including complement, IL18, and migratory genes (VEGFA/B) in comparison to blood-derived cells. Therapeutic targeting of this pathway with αIL-11 mAb in mice with RR experimental autoimmune encephalomyelitis (EAE) decreased clinical scores, CNS inflammatory infiltrates, and demyelination. αIL-11 mAb treatment decreased the numbers of NFκBp65+, NLRP3+, and IL-1ß+ monocytes in the CNS of mice with EAE. The results suggest that IL-11/IL-11R signaling in monocytes represents a therapeutic target in RRMS.

IL-11 Induces Encephalitogenic Th17 Cells in Multiple Sclerosis and Experimental Autoimmune Encephalomyelitis.

IL-11+CD4+ cells accumulate in the cerebrospinal fluid of patients with early relapsing-remitting multiple sclerosis (MS) and in active brain MS lesions. Mouse studies have confirmed a causal role of IL-11 in the exacerbation of relapsing-remitting experimental autoimmune encephalomyelitis (RREAE). Administration of IL-11 at the time of clinical onset of RREAE induced an acute exacerbation and increased clinical scores, which persisted during the entire course of the disease. IL-11 increased the numbers of spinal cord inflammatory foci, as well as the numbers of peripheral and CNS-infiltrating IL-17+CD4+ cells and IL-17A serum levels. Ag recall assays revealed that IL-11 induces IL-17A+, GM-CSF+, and IL-21+CD4+ myelin Ag-reactive cells. Passive transfer of these encephalitogenic CD4+ T cells induced severe RREAE with IL-17A+CCR6+ CD4+ and B cell accumulation within the CNS. Furthermore, passive transfer of nonmanipulated CNS-derived mononuclear cells from mice with RREAE after a single dose of IL-11 induced severe RREAE with increased accumulation of IL-17A+ and CCR6+ CD4+ cells within the CNS. These results suggest that IL-11 might serve as a biomarker of early autoimmune response and a selective therapeutic target for patients with early relapsing-remitting MS.

SHP-1 plays a crucial role in CD40 signaling reciprocity.

CD40 plays dual immunoregulatory roles in Leishmania major infection and tumor regression. The functional duality emerges from CD40-induced reciprocal p38MAPK and ERK-1/2 phosphorylations. Because phosphotyrosine-based signaling in hematopoietic cells is regulated by the phosphotyrosine phosphatase SHP-1, which is not implied in CD40 signaling, we examined whether SHP-1 played any roles in CD40-induced reciprocal signaling and anti-leishmanial function. We observed that a weaker CD40 stimulation increased SHP-1 activation. ERK-1/2 inhibition or p38MAPK overexpression inhibited CD40-induced SHP-1 activation. An ultra-low-dose, CD40-induced p38MAPK phosphorylation was enhanced by SHP-1 inhibition but reduced by SHP-1 overexpression. A reverse profile was observed with ERK-1/2 phosphorylation. SHP-1 inhibition reduced syk phosphorylation but increased lyn phosphorylation; syk inhibition reduced but lyn inhibition enhanced CD40-induced SHP-1 phosphorylation. Corroborating these findings, in L. major-infected macrophages, CD40-induced SHP-1 phosphorylation increased and SHP-1 inhibition enhanced CD40-induced p38MAPK activation and inducible NO synthase expression. IL-10 enhanced SHP-1 phosphorylation and CD40-induced ERK-1/2 phosphorylation but reduced the CD40-induced p38MAPK phosphorylation, whereas anti-IL-10 Ab exhibited reverse effects on these CD40-induced functions, identifying IL-10 as a crucial element in the SHP-1-MAPK feedback system. Lentivirally overexpressed SHP-1 rendered resistant C57BL/6 mice susceptible to the infection. Lentivirally expressed SHP-1 short hairpin RNA enhanced the CD40-induced L. major parasite killing in susceptible BALB/c mice. Thus, we establish an SHP-1-centered feedback system wherein SHP-1 modulates CD40-induced p38MAPK activation threshold and reciprocal ERK-1/2 activation, establishing itself as a critical regulator of CD40 signaling reciprocity and mechanistically re-emphasizing its role as a potential target against the diseases where CD40 is involved.

Differential expression of programmed death 1 (PD-1) on various immune cells and its role in human leprosy.

Leprosy is a chronic bacterial disease caused by Mycobacterium leprae. Leprosy patients have been found to have defects in T cells activation, which is critical to the clearance of the bacilli. Treg cell suppression is mediated by inhibitory cytokines such as IL10, IL-35 and TGF-ß and its frequency is higher in leprosy patients. Activation and overexpression of programmed death 1 (PD-1) receptor is considered to one of the pathways to inhibit T-cell response in human leprosy. In the current study we address the effect of PD-1 on Tregs function and its immuno-suppressive function in leprosy patients. Flow cytometry was used to evaluate the expression of PD-1 and its ligands on various immune cells T cells, B cells, Tregs and monocytes. We observed higher expression of PD-1 on Tregs is associated with lower production of IL-10 in leprosy patients. PD-1 ligands on T cells, B cells, Tregs and monocytes found to be higher in the leprosy patients as compared to healthy controls. Furthermore, in vitro blocking of PD-1 restores the Tregs mediated suppression of Teff and increase secretion of immunosuppressive cytokine IL-10. Moreover, overexpression of PD-1 positively correlates with disease severity as well as Bacteriological Index (BI) among leprosy patients. Collectively, our data suggested that PD-1 overexpression on various immune cells is associated with disease severity in human leprosy. Manipulation and inhibition of PD-1 signaling pathway on Tregs alter and restore the Treg cell suppression activity in leprosy patients.

Characterization of pH-induced conformational changes in recombinant DENV NS2B-NS3pro.

The increasing frequency of Dengue is a cause of severe epidemics and therefore demands strategies for effective prevention, diagnosis, and treatment. DENV-protease is being investigated as a potential therapeutic target. However, due to the flat and highly charged active site of the DENV-protease, designing orthosteric medicines is very difficult. In this study, we have done a thorough analysis of pH-dependent conformational changes in recombinantly expressed DENV protease using various spectroscopic techniques. Our spectroscopic study of DENV protease (NS2B-NS3pro) at different pH conditions gives important insights into the dynamicity of structural conformation. At physiological pH, the DENV-protease exists in a random-coiled state. Lowering the pH promotes the formation of alpha-helical and beta-sheet structures i.e. gain of secondary structure as shown by Far-UV CD. The light scattering and Thioflavin T (ThT)-binding assay proved the aggregation-prone tendency of DENV-protease at pH 4.0. Further, the confocal microscopy image intensity showed the amorphous aggregate formation of DENV protease at pH 4.0. Thus, the DENV protease acquires different conformations with changes in pH conditions. Together, these results have the potential to facilitate the design of a conformation destabilizer-based therapeutic strategy for dengue fever.

Do outcomes justify emergence of new cardiac centres.

OBJECTIVE: To assess if quality cardiac surgical results can be delivered in a third world country like Pakistan. METHODS: Our report focused on the initial 2-years experience (June 2005-June 2007) at a new institution Tabba Heart Institute, Karachi. Individual mortality rates of adult cardiovascular surgeries done at our institution were compared with the Society for Thoracic Surgery (STS), European Association of Cardiothoracic Surgery (EACTS) databases and one of the more commonly applied models for predicting post-operative mortality, EuroSCORE. All sets of data were not adjusted for risk. RESULTS: Total of 1017 open heart surgeries were performed. Age range for our series was 15-80 years, 777 were men and 240 females. Of these 891 were isolated CABG, 25AVR, 50 MVR, 27 AVR+MVR, 11 CABG+AVR and 13 CABG+MVR. 12.9% patients had LVEF < 30% and 11.7% had critical left main coronary disease. In all, 15% of our cases were performed on an emergency basis. Observed mortality rates at Tabba Heart Institute (3.94%) were much lower when compared to those documented by STS database (5.45%), EACTS (6.18%) and EuroSCORE (8.7%). CONCLUSION: With post-operative mortality an inverse indicator of quality health care, the results were good, despite several geographical, financial and demographical limitations in reproducing results comparable to international standards. This shows a maximum contribution in providing first grade cardiac support in a developing country like Pakistan.