Cysteinyl leukotriene receptor-1 as a potential target for host-directed therapy during chronic schistosomiasis in murine model.

Schistosomiasis remains the most devastating neglected tropical disease, affecting over 240 million people world-wide. The disease is caused by the eggs laid by mature female worms that are trapped in host's tissues, resulting in chronic Th2 driven fibrogranulmatous pathology. Although the disease can be treated with a relatively inexpensive drug, praziquantel (PZQ), re-infections remain a major problem in endemic areas. There is a need for new therapeutic drugs and alternative drug treatments for schistosomiasis. The current study hypothesized that cysteinyl leukotrienes (cysLTs) could mediate fibroproliferative pathology during schistosomiasis. Cysteinyl leukotrienes (cysLTs) are potent lipid mediators that are known to be key players in inflammatory diseases, such as asthma and allergic rhinitis. The present study aimed to investigate the role of cysLTR1 during experimental acute and chronic schistosomiasis using cysLTR1-/- mice, as well as the use of cysLTR1 inhibitor (Montelukast) to assess immune responses during chronic Schistosoma mansoni infection. Mice deficient of cysLTR1 and littermate control mice were infected with either high or low dose of Schistosoma mansoni to achieve chronic or acute schistosomiasis, respectively. Hepatic granulomatous inflammation, hepatic fibrosis and IL-4 production in the liver was significantly reduced in mice lacking cysLTR1 during chronic schistosomiasis, while reduced liver pathology was observed during acute schistosomiasis. Pharmacological blockade of cysLTR1 using montelukast in combination with PZQ reduced hepatic inflammation and parasite egg burden in chronically infected mice. Combination therapy led to the expansion of Tregs in chronically infected mice. We show that the disruption of cysLTR1 is dispensable for host survival during schistosomiasis, suggesting an important role cysLTR1 may play during early immunity against schistosomiasis. Our findings revealed that the combination of montelukast and PZQ could be a potential prophylactic treatment for chronic schistosomiasis by reducing fibrogranulomatous pathology in mice. In conclusion, the present study demonstrated that cysLTR1 is a potential target for host-directed therapy to ameliorate fibrogranulomatous pathology in the liver during chronic and acute schistosomiasis in mice.

Identifying quantitative sncRNAs signature using global sequencing as a potential biomarker for tuberculosis diagnosis and their role in regulating host response.

OBJECTIVES: The study aimed to identify a quantitative signature of circulating small non-coding RNAs (sncRNAs) as a biomarker for pulmonary tuberculosis disease (active-TB/ATB) and explore their regulatory roles in host-pathogen interactions and disease progression. METHODS: We conducted a cross-sectional study recruiting subjects diagnosed with active-TB (drug-sensitive and drug-resistant) and healthy controls. Sera samples were collected and utilized for preparing small RNA libraries. Quantitative patterns of circulating sncRNAs (miRNAs, piRNAs and tRFs) were identified via high-throughput sequencing and DeSeq2 analysis and validated in independent active-TB cohorts. Functional knockdown for two selected miRNAs were also performed. RESULTS: A diagnostic signature of four sncRNAs for both drug-sensitive and drug-resistant active-TB cases was validated, exhibiting an AUC of 0.96 (95% CI: 0.937-0.996, p < 0.001) with 86.7% sensitivity (95% CI: 0.775-0.932) and 91.7% specificity (95% CI: 0.730-0.990) in ROC analysis. Functional knockdown demonstrated regulatory roles of hsa-miR-223-5p and hsa-miR-10b-5p in Mycobacterium tuberculosis (Mtb) growth and pro-inflammatory cytokine expression (IL-6 and IL-8). CONCLUSION: The study identified a diagnostic tool utilizing a signature of four sncRNAs with high specificity and sensitivity, enhancing our understanding of sncRNAs as ATB diagnostic biomarker. Additionally, hsa-miR-223-5p and hsa-miR-10b-5p demonstrated potential roles in Mtb pathogenesis and host-response to infection.

Novel IL-4/HB-EGF-dependent crosstalk between eosinophils and macrophages controls liver regeneration after ischaemia and reperfusion injury.

OBJECTIVE: Previous studies indicate that eosinophils are recruited into the allograft following orthotopic liver transplantation and protect from ischaemia reperfusion (IR) injury. In the current studies, we aim to explore whether their protective function could outlast during liver repair. DESIGN: Eosinophil-deficient mice and adoptive transfer of bone marrow-derived eosinophils (bmEos) were employed to investigate the effects of eosinophils on tissue repair and regeneration after hepatic IR injury. Aside from exogenous cytokine or neutralising antibody treatments, mechanistic studies made use of a panel of mouse models of eosinophil-specific IL-4/IL-13-deletion, cell-specific IL-4rα-deletion in liver macrophages and hepatocytes and macrophage-specific deletion of heparin-binding epidermal growth factor-like growth factor (hb-egf). RESULT: We observed that eosinophils persisted over a week following hepatic IR injury. Their peak accumulation coincided with that of hepatocyte proliferation. Functional studies showed that eosinophil deficiency was associated with a dramatic delay in liver repair, which was normalised by the adoptive transfer of bmEos. Mechanistic studies demonstrated that eosinophil-derived IL-4, but not IL-13, was critically involved in the reparative function of these cells. The data further revealed a selective role of macrophage-dependent IL-4 signalling in liver regeneration. Eosinophil-derived IL-4 stimulated macrophages to produce HB-EGF. Moreover, macrophage-specific hb-egf deletion impaired hepatocyte regeneration after IR injury. CONCLUSION: Together, these studies uncovered an indispensable role of eosinophils in liver repair after acute injury and identified a novel crosstalk between eosinophils and macrophages through the IL-4/HB-EGF axis.

Single-cell transcriptomics identifies the differentiation trajectory from inflammatory monocytes to pro-resolving macrophages in a mouse skin allergy model.

Both monocytes and macrophages are heterogeneous populations. It was traditionally understood that Ly6Chi classical (inflammatory) monocytes differentiate into pro-inflammatory Ly6Chi macrophages. Accumulating evidence has suggested that Ly6Chi classical monocytes can also differentiate into Ly6Clo pro-resolving macrophages under certain conditions, while their differentiation trajectory remains to be fully elucidated. The present study with scRNA-seq and flow cytometric analyses reveals that Ly6ChiPD-L2lo classical monocytes recruited to the allergic skin lesion sequentially differentiate into Ly6CloPD-L2hi pro-resolving macrophages, via intermediate Ly6ChiPD-L2hi macrophages but not Ly6Clo non-classical monocytes, in an IL-4 receptor-dependent manner. Along the differentiation, classical monocyte-derived macrophages display anti-inflammatory signatures followed by metabolic rewiring concordant with their ability to phagocytose apoptotic neutrophils and allergens, therefore contributing to the resolution of inflammation. The failure in the generation of these pro-resolving macrophages drives the IL-1α-mediated cycle of inflammation with abscess-like accumulation of necrotic neutrophils. Thus, we clarify the stepwise differentiation trajectory from Ly6Chi classical monocytes toward Ly6Clo pro-resolving macrophages that restrain neutrophilic aggravation of skin allergic inflammation.

A Myeloid-Specific Lack of IL-4Rα Prevents the Development of Alternatively Activated Macrophages and Enhances Immunity to Experimental Cysticercosis.

To determine the role that the IL-4/IL13 receptor plays in the development of alternatively activated macrophages (AAM or M2) and their role in the regulation of immunity to the extraintestinal phase of the helminth parasite Taenia crassiceps, we followed the infection in a mouse strain lacking the IL-4Rα gene (IL-4Rα-/-) and in the macrophage/neutrophil-specific IL-4Rα-deficient mouse strain (LysMcreIL-4Rα-/lox or cre/LoxP). While 100% of T. crassiceps-infected IL-4Rα+/+ (WT) mice harbored large parasite loads, more than 50% of th eIL-4Rα-/- mice resolved the infection. Approximately 88% of the LysMcreIL-4Rα-/lox mice displayed a sterilizing immunity to the infection. The remaining few infected cre/LoxP mice displayed the lowest number of larvae in their peritoneal cavity. The inability of the WT mice to control the infection was associated with antigen-specific Th2-type responses with higher levels of IgG1, IL-4, IL-13, and total IgE, reduced NO production, and increased arginase activity. In contrast, IL-4Rα-/- semi-resistant mice showed a Th1/Th2 combined response. Furthermore, macrophages from the WT mice displayed higher transcripts for Arginase-1 and RELM-α, as well as increased expression of PD-L2 with robust suppressive activity over anti-CD3/CD28 stimulated T cells; all of these features are associated with the AAM or M2 macrophage phenotype. In contrast, both the IL-4Rα-/- and LysMcreIL-4Rα-/lox mice did not fully develop AAM or display suppressive activity over CD3/CD28 stimulated T cells, reducing PDL2 expression. Additionally, T-CD8+ but no T-CD4+ cells showed a suppressive phenotype with increased Tim-3 and PD1 expression in WT and IL-4Rα-/-, which were absent in T. crassiceps-infected LysMcreIL-4Rα-/lox mice. These findings demonstrate a critical role for the IL-4 signaling pathway in sustaining AAM and its suppressive activity during cysticercosis, suggesting a pivotal role for AAM in favoring susceptibility to T. crassiceps infection. Thus, the absence of these suppressor cells is one of the leading mechanisms to control experimental cysticercosis successfully.

Foxp3 and Bcl6 deficiency synergistically induces spontaneous development of atopic dermatitis-like skin disease.

Atopic dermatitis (AD) is a common chronic skin disease caused by immune dysfunction, specifically the hyperactivation of Th2 immunity. AD is a complex disease with multiple factors contributing to its development; however, the interaction between these factors is not fully understood. In this study, we demonstrated that the conditional deletion of both the forkhead box p3 (Foxp3) and B-cell lymphoma 6 (Bcl6) genes induced the spontaneous development of AD-like skin inflammation with hyperactivation of type 2 immunity, skin barrier dysfunction, and pruritus, which were not induced by the single deletion of each gene. Furthermore, the development of AD-like skin inflammation was largely dependent on IL-4/13 signaling but not on immunoglobulin E (IgE). Interestingly, we found that the loss of Bcl6 alone increased the expression of thymic stromal lymphopoietin (TSLP) and interleukin (IL)-33 in the skin, suggesting that Bcl6 controls Th2 responses by suppressing TSLP and IL-33 expression in epithelial cells. Our results suggest that Foxp3 and Bcl6 cooperatively suppress the pathogenesis of AD. Furthermore, these results revealed an unexpected role of Bcl6 in suppressing Th2 responses in the skin.

Environmental and microbial factors influence affective and cognitive behavior in C57BL/6 sub-strains.

C57BL/6 mice are one of the most widely used inbred strains in biomedical research. Early separation of the breeding colony has led to the development of several sub-strains. Colony separation led to genetic variation development driving numerous phenotypic discrepancies. The reported phenotypic behavior differences between the sub-strains were, however; not consistent in the literature, suggesting the involvement of factors other than host genes. Here, we characterized the cognitive and affective behavior of C57BL/6J and C57BL/6N mice in correlation with the immune cell profile in the brain. Furthermore, faecal microbiota transfer and mice co-housing techniques were used to dissect microbial and environmental factors' contribution, respectively, to cognitive and affective behavior patterns. We first noted a unique profile of locomotor activity, immobility pattern, and spatial and non-spatial learning and memory abilities between the two sub-strains. The phenotypic behavior profile was associated with a distinct difference in the dynamics of type 2 cytokines in the meninges and brain parenchyma. Analysing the contribution of microbiome and environmental factors to the noted behavioral profile, our data indicated that while immobility pattern was genetically driven, locomotor activity and cognitive abilities were highly sensitive to alterations in the gut microbiome and environmental factors. Changes in the phenotypic behavior in response to these factors were associated with changes in immune cell profile. While microglia were highly sensitive to alteration in gut microbiome, immune cells in meninges were more resilient. Collectively, our findings demonstrated a direct impact of environmental conditions on gut microbiota which subsequently impacts the brain immune cell profile that could modulate cognitive and affective behavior. Our data further highlight the importance of characterizing the laboratory available strain/sub-strain to select the most appropriate one that fits best the study purpose.

Autoimmune Valvular Carditis Requires Endothelial Cell TNFR1 Expression.

BACKGROUND: Inflammation is a key driver of cardiovascular pathology, and many systemic autoimmune/rheumatic diseases are accompanied by increased cardiac risk. In the K/B.g7 mouse model of coexisting systemic autoantibody-mediated arthritis and valvular carditis, valve inflammation depends on macrophage production of TNF (tumor necrosis factor) and IL-6 (interleukin-6). Here, we sought to determine if other canonical inflammatory pathways participate and to determine whether TNF signaling through TNFR1 (tumor necrosis factor receptor 1) on endothelial cells is required for valvular carditis. METHODS: We first asked if type 1, 2, or 3 inflammatory cytokine systems (typified by IFNγ, IL-4, and IL-17, respectively) were critical for valvular carditis in K/B.g7 mice, using a combination of in vivo monoclonal antibody blockade and targeted genetic ablation studies. To define the key cellular targets of TNF, we conditionally deleted its main proinflammatory receptor, TNFR1, in endothelial cells. We analyzed how the absence of endothelial cell TNFR1 affected valve inflammation, lymphangiogenesis, and the expression of proinflammatory genes and molecules. RESULTS: We found that typical type 1, 2, and 3 inflammatory cytokine systems were not required for valvular carditis, apart from a known initial requirement of IL-4 for autoantibody production. Despite expression of TNFR1 on a wide variety of cell types in the cardiac valve, deleting TNFR1 specifically on endothelial cells protected K/B.g7 mice from valvular carditis. This protection was accompanied by reduced expression of VCAM-1 (vascular cell adhesion molecule), fewer valve-infiltrating macrophages, reduced pathogenic lymphangiogenesis, and diminished proinflammatory gene expression. CONCLUSIONS: TNF and IL-6 are the main cytokines driving valvular carditis in K/B.g7 mice. The interaction of TNF with TNFR1 specifically on endothelial cells promotes cardiovascular pathology in the setting of systemic autoimmune/rheumatic disease, suggesting that therapeutic targeting of the TNF:TNFR1 interaction could be beneficial in this clinical context.

IL-4Rα signalling in B cells and T cells play differential roles in acute and chronic atopic dermatitis.

Atopic dermatitis (AD) is a common pruritic inflammatory skin disease with complex environmental and genetic predisposing factors. Primary skin barrier dysfunction and aberrant T helper 2 (TH2) responses to common allergens, together with increased serum IgE antibodies, characterise the disease. B and T cells are essential in the disease manifestation, however, the exact mechanism of how these cells is involved is unclear. Targeting interleukin 4 receptor alpha (IL-4Rα), an IL-4/IL-13 signalling axis, with dupilumab shows efficacy in AD. We investigated the importance of IL-4Rα signalling specifically on B and T cells during acute and chronic models of AD. We used House dust mite (HDM) and Ovalbumin (OVA) in chronic models and a low-calcemic analog of vitamin D (MC903) for acute models of AD. We used mb1creIL-4Rα-/lox, iLCKcreIL-4Rα-/lox, LCKcreIL-4Rα-/lox, CD4creIL-4Rα-/lox, Foxp3creIL-4Rα-/lox and IL-4Rα-/lox littermate controls. IL-4Rα-responsive B cells were essential in serum IgE levels, but not in epidermal thickening in both chronic and acute models. IL-4Rα-responsive T cells were essential in epidermal thickening in the pan-T cell, but not CD4 or CD8 T cells suggesting the importance of γδT cells during acute AD. Our results suggest that IL-4Rα responsiveness on innate T cells regulates acute atopic dermatitis, while on B cells it regulates IgE.

The metabolomics of a protein kinase C delta (PKCδ) knock-out mouse model.

INTRODUCTION: PKCδ is ubiquitously expressed in mammalian cells and its dysregulation plays a key role in the onset of several incurable diseases and metabolic disorders. However, much remains unknown about the metabolic pathways and disturbances induced by PKC deficiency, as well as the metabolic mechanisms involved. OBJECTIVES: This study aims to use metabolomics to further characterize the function of PKC from a metabolomics standpoint, by comparing the full serum metabolic profiles of PKC deficient mice to those of wild-type mice. METHODS: The serum metabolomes of PKCδ knock-out mice were compared to that of a wild-type strain using a GCxGC-TOFMS metabolomics research approach and various univariate and multivariate statistical analyses. RESULTS: Thirty-seven serum metabolite markers best describing the difference between PKCδ knock-out and wild-type mice were identified based on a PCA power value > 0.9, a t-test p-value < 0.05, or an effect size > 1. XERp prediction was also done to accurately select the metabolite markers within the 2 sample groups. Of the metabolite markers identified, 78.4% (29/37) were elevated and 48.65% of these markers were fatty acids (18/37). It is clear that a total loss of PKCδ functionality results in an inhibition of glycolysis, the TCA cycle, and steroid synthesis, accompanied by upregulation of the pentose phosphate pathway, fatty acids oxidation, cholesterol transport/storage, single carbon and sulphur-containing amino acid synthesis, branched-chain amino acids (BCAA), ketogenesis, and an increased cell signalling via N-acetylglucosamine. CONCLUSION: The charaterization of the dysregulated serum metabolites in this study, may represent an additional tool for the early detection and screening of PKCδ-deficiencies or abnormalities.

Arteannuin-B and (3-Chlorophenyl)-2-Spiroisoxazoline Derivative Exhibit Anti-Inflammatory Effects in LPS-Activated RAW 264.7 Macrophages and BALB/c Mice-Induced Proinflammatory Responses via Downregulation of NF-κB/P38 MAPK Signaling.

Host inflammatory responses are key to protection against injury; however, persistent inflammation is detrimental and contributes to morbidity and mortality. Herein, we demonstrated the anti-inflammatory role of Arteannuin-B (1) and its new spirocyclic-2-isoxazoline derivative JR-9 and their side effects in acute inflammatory condition in vivo using LPS-induced cytokines assay, carrageenan-induced paw edema, acetic acid-induced writhing and tail immersion. The results show that the spirocyclic-2-isoxazoline derivative is a potent anti-inflammatory agent with minimal cell toxicity as compared to Arteannuin-B. In addition, the efficacies of these compounds were also validated by flow cytometric, computational, and histopathological analysis. Our results show that the anti-inflammatory response of JR-9 significantly reduces the ability of mouse macrophages to produce NO, TNF-α, and IL-6 following LPS stimulation. Therefore, JR-9 is a prospective candidate for the development of anti-inflammatory drugs and its molecular mechanism is likely related to the regulation of NF-κB and MAPK signaling pathway.

Interleukin-4 receptor alpha signaling regulates monocyte homeostasis.

Interleukin-4 (IL-4) and its receptors (IL-4R) promote the proliferation and polarization of macrophages. However, it is unknown if IL-4R also influences monocyte homeostasis and if steady state IL-4 levels are sufficient to affect monocytes. Employing full IL-4 receptor alpha knockout mice (IL-4Rα-/- ) and mice with a myeloid-specific deletion of IL-4Rα (IL-4Rαf/f LysMcre ), we show that IL-4 acts as a homeostatic factor regulating circulating monocyte numbers. In the absence of IL-4Rα, murine monocytes in blood were reduced by 50% without altering monocytopoiesis in the bone marrow. This reduction was accompanied by a decrease in monocyte-derived inflammatory cytokines in the plasma. RNA sequencing analysis and immunohistochemical staining of splenic monocytes revealed changes in mRNA and protein levels of anti-apoptotic factors including BIRC6 in IL-4Rα-/- knockout animals. Furthermore, assessment of monocyte lifespan in vivo measuring BrdU+ cells revealed that the lifespan of circulating monocytes was reduced by 55% in IL-4Rα-/- mice, whereas subcutaneously applied IL-4 prolonged it by 75%. Treatment of human monocytes with IL-4 reduced the amount of dying monocytes in vitro. Furthermore, IL-4 stimulation reduced the phosphorylation of proteins involved in the apoptosis pathway, including the phosphorylation of the NFκBp65 protein. In a cohort of human patients, serum IL-4 levels were significantly associated with monocyte counts. In a sterile peritonitis model, reduced monocyte counts resulted in an attenuated recruitment of monocytes upon inflammatory stimulation in IL-4Rαf/f LysMcre mice without changes in overall migratory function. Thus, we identified a homeostatic role of IL-4Rα in regulating the lifespan of monocytes in vivo.

Lyl1-deficiency promotes inflammatory responses and increases mycobacterial burden in response to Mycobacterium tuberculosis infection in mice.

Lymphoblastic leukemia 1 (Lyl1) is a well-studied transcription factor known to exhibit oncogenic potential in various forms of leukemia with pivotal roles in hematopoietic stem cell biology. While its role in early hematopoiesis is well established, its function in mature innate cells is less explored. Here, we identified Lyl1 as a drastically perturbed gene in the Mycobacterium tuberculosis (Mtb) infected mouse macrophage transcriptome. We report that Lyl1 downregulation upon immune stimulation is a host-driven process regulated by NFκB and MAP kinase pathways. Interestingly, Lyl1-deficient macrophages have decreased bacterial killing potential with reduced nitric oxide (NO) levels while expressing increased levels of pro-inflammatory interleukin-1 and CXCL1. Lyl1-deficient mice show reduced survival to Mtb HN878 infection with increased bacterial burden and exacerbated inflammatory responses in chronic stages. We observed that increased susceptibility to infection was accompanied by increased neutrophil recruitment and IL-1, CXCL1, and CXCL5 levels in the lung homogenates. Collectively, these results suggest that Lyl1 controls Mtb growth, reduces neutrophilic inflammation and reveals an underappreciated role for Lyl1 in innate immune responses.

Host-Directed Targeting of LincRNA-MIR99AHG Suppresses Intracellular Growth of Mycobacterium tuberculosis.

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) kills 1.6 million people worldwide every year, and there is an urgent need for targeting host-pathogen interactions as a strategy to reduce mycobacterial resistance to current antimicrobials. Noncoding RNAs are emerging as important regulators of numerous biological processes and avenues for exploitation in host-directed therapeutics. Although long noncoding RNAs (lncRNAs) are abundantly expressed in immune cells, their functional role in gene regulation and bacterial infections remains understudied. In this study, we identify an immunoregulatory long intergenic noncoding RNA, lincRNA-MIR99AHG, which is upregulated in mouse and human macrophages upon IL-4/IL-13 stimulation and downregulated after clinical Mtb HN878 strain infection and in peripheral blood mononuclear cells from active TB patients. To evaluate the functional role of lincRNA-MIR99AHG, we used antisense locked nucleic acid (LNA) GapmeR-mediated antisense oligonucleotide (ASO) lncRNA knockdown experiments. Knockdown of lincRNA-MIR99AHG with ASOs significantly reduced intracellular Mtb growth in mouse and human macrophages and reduced pro-inflammatory cytokine production. In addition, in vivo treatment of mice with MIR99AHG ASOs reduced the mycobacterial burden in the lung and spleen. Furthermore, in macrophages, lincRNA-MIR99AHG is translocated to the nucleus and interacts with high affinity to hnRNPA2/B1 following IL-4/IL-13 stimulation and Mtb HN878 infection. Together, these findings identify lincRNA-MIR99AHG as a positive regulator of inflammation and macrophage polarization to promote Mtb growth and a possible target for adjunctive host-directed therapy against TB.

Type 2 immunity: a two-edged sword in schistosomiasis immunopathology.

Schistosomiasis is the second most debilitating neglected tropical disease globally after malaria, with no available therapy to control disease-driven immunopathology. Although schistosomiasis induces a markedly heterogenous immune response, type 2 immunity is the dominating immune response following oviposition. While type 2 immunity has a crucial role in granuloma formation and host survival during the acute stage of disease, its chronic activation can result in tissue scarring, fibrosis, and organ impairment. Here, we discuss recent advances in schistosomiasis, demonstrating how different immune and non-immune cells and signaling pathways are involved in the induction, maintenance, and regulation of type 2 immunity. A better understanding of these immune responses during schistosomiasis is essential to inform the potential development of candidate therapeutic strategies that fine-tune type 2 immunity to ideally modulate schistosomiasis immunopathology.

Schistosoma mansoni infection induces plasmablast and plasma cell death in the bone marrow and accelerates the decline of host vaccine responses.

Schistosomiasis is a potentially lethal parasitic disease that profoundly impacts systemic immune function in chronically infected hosts through mechanisms that remain unknown. Given the immunoregulatory dysregulation experienced in infected individuals, this study examined the impact of chronic schistosomiasis on the sustainability of vaccine-induced immunity in both children living in endemic areas and experimental infections in mice. Data show that chronic Schistosoma mansoni infection impaired the persistence of vaccine specific antibody responses in poliovirus-vaccinated humans and mice. Mechanistically, schistosomiasis primarily fostered plasmablast and plasma cell death in the bone marrow and removal of parasites following praziquantel treatment reversed the observed cell death and partially restored vaccine-induced memory responses associated with increased serum anti-polio antibody responses. Our findings strongly suggest a previously unrecognized mechanism to explain how chronic schistosomiasis interferes with an otherwise effective vaccine regimen and further advocates for therapeutic intervention strategies that reduce schistosomiasis burden in endemic areas prior to vaccination.

Intranasally administered S-MGB-364 displays antitubercular activity and modulates the host immune response to Mycobacterium tuberculosis infection.

BACKGROUND: Previously, we evaluated the intracellular mycobactericidal activity of the minor groove binder, S-MGB-364 against the clinical Mycobacterium tuberculosis (Mtb) strain HN878 in macrophages. OBJECTIVES: To assess the mycobactericidal activity of S-MGB-364 in Mtb-infected mice. Further, we investigated a plausible DNA binding mechanism of action of S-MGB-364. METHODS: The anti-TB and host immune effects of intranasal S-MGB-364 or S-MGB-364 encapsulated in non-ionic surfactant vesicles (NIV) were assessed in Mtb-infected mice by cfu enumeration, ELISA, histology, and flow cytometry. DNA binding was examined using native mass spectrometry and UV-vis thermal melt determination. S-MGB interference with DNA-centric biological events was assessed using a representative panel of Mtb and human topoisomerase I, and gyrase assays. RESULTS: S-MGB-364 bound strongly to DNA as a dimer, significantly increasing the stability of the DNA:S-MGB complex compared with DNA alone. Moreover, S-MGB-364 inhibited the relaxation of Mtb topoisomerase I but not the human form. In macrophages, S-MGB-364 or S-MGB-364-NIV did not cause DNA damage as shown by the low γ-H2AX expression. Importantly, in the lungs, the intranasal administration of S-MGB-364 or S-MGB-364-NIV formulation in Mtb-infected mice was non-toxic and resulted in a ∼1 log cfu reduction in mycobacterial burden, reduced the expression of proinflammatory cytokines/chemokines, altered immune cell recruitment, and importantly reduced recruitment of neutrophils. CONCLUSIONS: Together, these data provide proof of concept for S-MGBs as novel anti-TB therapeutics in vivo.

n-3 long-chain PUFA promote antibacterial and inflammation-resolving effects in Mycobacterium tuberculosis-infected C3HeB/FeJ mice, dependent on fatty acid status.

Non-resolving inflammation is characteristic of tuberculosis (TB). Given their inflammation-resolving properties, n-3 long-chain PUFA (n-3 LCPUFA) may support TB treatment. This research aimed to investigate the effects of n-3 LCPUFA on clinical and inflammatory outcomes of Mycobacterium tuberculosis-infected C3HeB/FeJ mice with either normal or low n-3 PUFA status before infection. Using a two-by-two design, uninfected mice were conditioned on either an n-3 PUFA-sufficient (n-3FAS) or -deficient (n-3FAD) diet for 6 weeks. One week post-infection, mice were randomised to either n-3 LCPUFA supplemented (n-3FAS/n-3+ and n-3FAD/n-3+) or continued on n-3FAS or n-3FAD diets for 3 weeks. Mice were euthanised and fatty acid status, lung bacterial load and pathology, cytokine, lipid mediator and immune cell phenotype analysed. n-3 LCPUFA supplementation in n-3FAS mice lowered lung bacterial loads (P = 0·003), T cells (P = 0·019), CD4+ T cells (P = 0·014) and interferon (IFN)-γ (P < 0·001) and promoted a pro-resolving lung lipid mediator profile. Compared with n-3FAS mice, the n-3FAD group had lower bacterial loads (P = 0·037), significantly higher immune cell recruitment and a more pro-inflammatory lipid mediator profile, however, significantly lower lung IFN-γ, IL-1α, IL-1ß and IL-17, and supplementation in the n-3FAD group provided no beneficial effect on lung bacterial load or inflammation. Our study provides the first evidence that n-3 LCPUFA supplementation has antibacterial and inflammation-resolving benefits in TB when provided 1 week after infection in the context of a sufficient n-3 PUFA status, whilst a low n-3 PUFA status may promote better bacterial control and lower lung inflammation not benefiting from n-3 LCPUFA supplementation.