TLR-CD40 Cross-Talk in Anti-Leishmanial Immune Response

Insights into inflammasome regulation: cellular, molecular, and pathogenic control of inflammasome activation

Maintenance of immune homeostasis is an intricate process wherein inflammasomes play a pivotal role by contributing to innate and adaptive immune responses. Inflammasomes are ensembles of adaptor proteins that can trigger a signal following innate sensing of pathogens or non-pathogens eventuating in the inductions of IL-1β and IL-18. These inflammatory cytokines substantially influence the antigen-presenting cell's costimulatory functions and T helper cell differentiation, contributing to adaptive immunity. As acute and chronic disease conditions may accompany parallel tissue damage, we analyze the critical role of extracellular factors such as cytokines, amyloids, cholesterol crystals, etc., intracellular metabolites, and signaling molecules regulating inflammasome activation/inhibition. We develop an operative framework for inflammasome function and regulation by host cell factors and pathogens. While inflammasomes influence the innate and adaptive immune components' interplay modulating the anti-pathogen adaptive immune response, pathogens may target inflammasome inhibition as a survival strategy. As trapped between health and diseases, inflammasomes serve as promising therapeutic targets and their modus operandi serves as a scientific rationale for devising better therapeutic strategies.

Bioinformatics analysis of gene expression profile data to screen key genes involved in intracranial aneurysms

Intracranial aneurysm (IA) is a cerebrovascular disease with a high mortality rate. The pathogenesis of IA remains unclear and the treatment limited. The purpose of the present study was to identify the key genes expressed in IAs and provide the basis for further research and treatment. The raw dataset GSE75436 was downloaded from Gene Expression Omnibus, including 15 IA samples and 15 matched superficial temporal artery (STA) samples. Then, differentially expressed genes (DEGs) were identified using the limma package in R software. Hierarchical clustering analysis was performed on the DEGs using the gplot2 package in R. Database for Annotation, Visualization, and Integrated Discovery (DAVID) online tools were used to perform gene ontology (GO) functional enrichment analysis. DAVID and gene set enrichment analysis were separately used to perform the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. The intersections of the two results were selected as common KEGG pathways. Protein-protein interaction (PPI) analysis among the DEGs involved in the common KEGG pathways was performed using Search Tool for the Retrieval of Interacting Genes online tools, and visualized with Cytoscape software. A total of 782 DEGs were identified, comprising 392 upregulated and 390 downregulated DEGs. Hierarchical clustering demonstrated that the DEGs could precisely distinguish the IAs from the STAs. The GO enrichment analysis demonstrated that the upregulated DEGs were mainly involved in the inflammatory response and the management of extracellular matrix, and the downregulated DEGs were mainly involved in the process of vascular smooth muscle contraction. The KEGG pathway enrichment analysis demonstrated that the common pathways were ‘leishmaniasis’, ‘Toll-like receptor signaling pathway’ and ‘vascular smooth muscle contraction’. In the PPI network, tumor necrosis factor (TNF), interleukin 8 and Toll-like receptor 4 had the highest degrees; they were associated with the inflammatory response. The Toll-like receptor signaling pathway and TNF gene may serve as targets for future research and treatment.

Association of CD40 SNPs with Moyamoya in a Chinese children population

Background: The etiology of Moyamoya disease (MMD) remains unknown to a large extent. Immune and inflammation dysfunction may play a role in the pathogenesis of this rare disease. Coexisting Kawasaki disease (KD) with MMD were reported and both diseases have a feature of vasculopathy, raising the hypothesis that there may be some common pathologic factors. We investigated single nucleotide polymorphisms (SNPs) previously identified in KD and performed a genetic analysis among Chinese pediatric patients with MMD. Results: We analyzed patients' DNA for the SNPs in B lymphoid tyrosine kinase, CD40, and coatomer protein complex beta-2 subunit, which had been associated with KD by literatures. Genotyping was performed by sequencing the genetic regions containing the SNPs with customized primers. A total of 5 genotype polymorphisms were examined among 48 pediatric MMD cases and 50 healthy controls. The mean age of MMD children was 6.72 ± 3.63 years old, while 7.31 ± 3.79 in controls. We found two SNPs of CD40 were associated with MMD. Polymorphisms rs4813003 major allele CC and rs1535045 minor allele TT were significantly higher in MMD cases. The other SNPs showed no statistical difference between MMD cases and controls. Conclusions: Our findings provide evidence that there may be a relationship between MMD and auto-immune dysfunction. We hypothesize that these genetic features may lead to the pathogenesis within the vascular wall. Further study regarding whether CD40 can function as the personalized target of MMD should be investigated in future.

IL-21/anti-Tim1/CD40 ligand promotes B10 activity in vitro and alleviates bone loss in experimental periodontitis in vivo

IL-10-expressing regulatory B cells (B10) play an essential role in immune system balance by suppressing excessive inflammatory responses. In this study, we investigated induction of B 10 cell's IL-10 competency in vitro and its effect on ligature-induced experimental periodontitis in vivo. Spleen B cells were isolated from C57BL/6J mice and cultured for 48h under the following conditions: control, CD40L, IL-21, anti-Tim1, CD40L+IL-21, CD40L+anti-Tim1, CD40L+IL-21+anti-Tim1. Silk ligatures were tied around both maxillary second molars of C57BL/6J mice for two weeks. Optimized combination of CD40L, IL-21 and anti-Tim1 and vehicle were injected into contralateral side of palatal gingiva on days 3, 6 and 9. The palatal gingival tissues and maxillary bone were collected on day 14 to determine expressions of IL-10 and periodontal bone resorption respectively. Our results demonstrated that IL-10 expressions of cultured spleen B cells were significantly increased in the presence of CD40L, IL-21 and anti-Tim1 combination when compared with control groups. Gingival IL-10 mRNA and protein expressions were significantly increased after injection of CD40L, IL-21 and anti-Tim1 combination, when compared to the control side. The gingival RANKL expression and periodontal bone loss were significantly decreased on the combination treatment side, as compared to the control side. These results suggest that combination of IL-21, anti-Tim1 and CD40L treatment induced B10 cell's IL-10 competency in vitro and inhibited periodontal bone loss in ligature-induced experimental periodontitis.

Successful Therapy of Murine Visceral Leishmaniasis with Astrakurkurone, a Triterpene Isolated from the Mushroom Astraeus hygrometricus, Involves the Induction of Protective Cell-Mediated Immunity and TLR9

In our previous report, we showed that astrakurkurone, a triterpene isolated from the Indian mushroom Astraeus hygrometricus (Pers.) Morgan, induced reactive oxygen species, leading to apoptosis in Leishmania donovani promastigotes, and also was effective in inhibiting intracellular amastigotes at the 50% inhibitory concentration of 2.5 μg/ml. The aim of the present study is to characterize the associated immunomodulatory potentials and cellular activation provided by astrakurkurone, leading to effective antileishmanial activity in vitro and in vivo Astrakurkurone-mediated antileishmanial activity was evaluated by real-time PCR and flow cytometry. The involvement of Toll-like receptor 9 (TLR9) was studied by in vitro assay in the presence of a TLR9 agonist and antagonist and by in silico modeling of a three-dimensional structure of the ectodomain of TLR9 and its interaction with astrakurkurone. Astrakurkurone caused a significant increase in TLR9 expression of L. donovani-infected macrophages along with the activation of proinflammatory responses. The involvement of TLR9 in astrakurkurone-mediated amastigote killing has been evidenced from the fact that a TLR9 agonist (CpG, ODN 1826) in combination with astrakurkurone enhanced the amastigote killing, while a TLR9 antagonist (bafilomycin A1) alone or in combination with astrakurkurone curbed the amastigote killing, which could be further justified by in silico evidence of docking between mouse TLR9 and astrakurkurone. Astrakurkurone was found to reduce the parasite burden in vivo by inducing protective cytokines, gamma interferon and interleukin 17. Moreover, astrakurkurone was nontoxic toward peripheral blood mononuclear cells of immunocompromised patients with visceral leishmaniasis. Astrakurkurone, a nontoxic antileishmanial, enhances the immune efficiency of host cells, leading to parasite clearance in vitro and in vivo.

Cinnamic acid derived compounds loaded into liposomes: antileishmanial activity, production standardisation and characterisation

Synthetic compounds derived from cinnamic acid were tested in cultures containing the promastigote form of Leishmania amazonensis and the dimethylsulphoxide solution of B2 compound (2.0 mg/mL) led to a 92% decrease of leishmania in 96 h of treatment. Then, different liposomal systems (diameters ∼200 nm) were prepared by the extrusion method in the presence and absence of compounds studied. DSC thermograms of the liposomes in the presence of these compounds caused changes in ΔH, Tm and ΔT1/2, compared to controls, indicating that there was an interaction of the compounds with the lipid bilayer. Assays with negatively charged liposomal systems containing these drugs in L. amazonensis cultures led to a 50-80% decrease in the number of leishmanias with a concentration to 100 times lower when compared to the B2 initial test. These liposomal systems are promoting more interaction and delivery of the compounds and proved to be an efficient, stable and promising system.