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bioRxiv2018

Regression of solid breast tumours in mice by Newcastle disease virus is associated with production of apoptosis related-cytokines

BackgroundDifferent strains of Newcastle disease virus (NDV) worldwide proved to have tumouricidal activity in several types of cancer cells. However, the possible anti-cancer activity of Malaysian NDV AF2240 strain and its mechanism of action remains unknown. The ability of cytokine-related apoptosis-inducing NDV AF2240 to treat breast cancer was investigated in the current study.\n\nMethodsA total of 90 mice were used and divided into 15 groups, each group comprising of 6 mice. Tumour, body weight and mortality of the mice were determined throughout the experiment, to observe the effect of NDV and NDV+Tamoxifen treatments on the mice. In addition, the toxic effect of the treatments was determined through liver function test. In order to elucidate the involvement of cytokine production induced by NDV, a total of six cytokines, i.e. IL-6, IFN-{gamma}, MCP-1, IL-10, IL12p70 and TNF- were measured using cytometric bead array assay (plasma) and enzyme-linked immunosorbent spot (isolated splenocytes).\n\nResultsThe results demonstrated that 4T1 breast cancer cells in allotransplanted mice treated with AF2240 showed a noticeable inhibition in tumour growth and induce apoptotic-related cytokines.\n\nConclusionNDV AF2240 suppression of breast tumour growth is associated with induction of apoptotic-related cytokines.

immunology↗

bioRxiv2018

Corrigendum to: T cell apoptosis at the maternal-fetal interface in early human pregnancy, involvement of galectin-1.- A correction with an important twist.

We previously published a paper reporting the apoptotic nature of first trimester human decidual T cells (Kopcow et al 2008). New experiments and data re-analysis produced confirmatory, negative and contradictory results. We had previously shown by TUNEL and sub diploid DNA content analysis (SD) that ex-vivo decidual T cells, isolated either as CD3+ cells or as CD4+/8+ cells, are apoptotic and that the level of apoptosis differs significantly from peripheral blood T cells isolated in a similar way. Data re-examination including data points previously unintentionally ignored results in indetermination in the dataset structure with contradictory statistical significance results between TUNEL and SD and the two isolation approaches. Furthermore, data disaggregation and granular examination reveals discrepant TUNEL and SD readings within individual samples. We have previously shown that decidual CD3+ lymphocytes stain brighter with AnnexinV -Fitc than peripheral blood T cells and other decidual lympohocyte populations. Independent repetitions with modified and alternative isolation protocols using different flow cytometry equipment in the hands of another researcher failed to reproduce those results, while side by side repetition under the published conditions as well as under the alternative isolation protocol reproduced the published pattern when samples were ran in the same equipment used for the publication. A reflection on these results proposes to understand the scientific paper as one among other possible constructed narratives.

immunology↗

bioRxiv2018

Pathologically distinct fibroblast subsets drive inflammation and tissue damage in arthritis

The identification of lymphocyte subsets with non-overlapping effector functions has been pivotal to the development of targeted therapies in immune mediated inflammatory diseases (IMIDs). However it remains unclear whether fibroblast subclasses with non-overlapping functions also exist and are responsible for the wide variety of tissue driven processes observed in IMIDs such as inflammation and damage. Here we identify and describe the biology of distinct subsets of fibroblasts responsible for mediating either inflammation or tissue damage in arthritis. We show that deletion of FAP+ synovial cells suppressed both inflammation and bone erosions in murine models of resolving and persistent arthritis. Single cell transcriptional analysis identified two distinct fibroblast subsets: FAP+ THY1+ immune effector fibroblasts located in the synovial sub-lining, and FAP+ THY1- destructive fibroblasts restricted to the synovial lining. When adoptively transferred into the joint, FAP + THY1- fibroblasts selectively mediate bone and cartilage damage with little effect on inflammation whereas transfer of FAP + THY1+ fibroblasts resulted in a more severe and persistent inflammatory arthritis, with minimal effect on bone and cartilage. Our findings describing anatomically discrete, functionally distinct fibroblast subsets with non-overlapping functions have important implications for cell based therapies aimed at modulating inflammation and tissue damage.

immunology↗

bioRxiv2018

Expression of the Phosphatase Ppef2 Controls Survival and Function of CD8+ Dendritic Cells

Apoptotic cell death of Dendritic cells (DCs) is critical for immune homeostasis. Although intrinsic mechanisms controlling DC death have not been fully characterized up to now, experimentally enforced inhibition of DC-death causes various autoimmune diseases in model systems. We have generated mice deficient for Protein Phosphatase with EF-Hands 2 (Ppef2), which is selectively expressed in CD8+ DCs, but not in other related DC subtypes such as tissue CD103+ DCs. Ppef2 is down-regulated rapidly upon maturation of DCs by toll-like receptor stimuli, but not upon triggering of CD40. Ppef2-deficient CD8+ DCs accumulate the pro-apoptotic Bcl-2-like protein 11 (Bim) and show increased apoptosis and reduced competitve repopulation capacities. Furthermore, Ppef2-/-CD8+ DCs have strongly diminished antigen presentation capacities in vivo, as CD8+ T cells primed by Ppef2-/- CD8+ DCs undergo reduced expansion. In conclusion, our data suggests that Ppef2 is crucial to support survival of immature CD8+ DCs, while Ppef2 down-regulation during DC-maturation limits T cell responses.

immunology↗

bioRxiv2018

Detecting T-cell receptors involved in immune responses from single repertoire snapshots

Hypervariable T-cell receptors (TCR) play a key role in adaptive immunity, recognising a vast diversity of pathogen-derived antigens. High throughput sequencing of TCR repertoires (RepSeq) produces huge datasets of T-cell receptor sequences from blood and tissue samples [1, 2]. However, our ability to extract clinically relevant information from RepSeq data is limited, mainly because little is known about TCR-disease associations. Here we present a statistical approach called ALICE (Antigen-specific Lymphocyte Identification by Clustering of Expanded sequences) that identifies TCR sequences that are actively involved in the current immune response from a single RepSeq sample, and apply it to repertoires of patients with a variety of disorders -- autoimmune disease (ankylosing spondylitis [3]), patients under cancer immunotherapy [4, 5], or subject to an acute infection (live yellow fever vaccine [6]). The methods robustness is demonstrated by the agreement of its predictions with independent assays, and is supported by its ability to selectively detect responding TCR in the memory but not in the naive subset. ALICE requires no longitudinal data collection [6, 7] nor large cohorts [8-10], and is thus directly applicable to most RepSeq datasets. Its results facilitate the identification of TCR variants associated with a wide variety of diseases and conditions, which can be used for diagnostics, rational vaccine design and evaluation of the adaptive immune system state.

immunology↗

bioRxiv2018

Specific activation of HIV-1 from monocytic reservoir cells by bromodomain inhibitor in humanized mice in vivo

The combination antiretroviral therapy (cART) effectively suppresses HIV-1 infection and enables HIV-infected individuals to live long productive lives. However, the persistence of HIV-1 reservoir cells with latent or low-replicating HIV-1 in patients under cART make HIV-1 infection an incurable disease. Recent studies have focused on the development of strategies such as epigenetic modulators to activate and purge these reservoirs. Bromodomain inhibitors (BETi) are epigenetic modulating compounds able to activate viral transcription in HIV-1 latency cell lines in a positive transcription elongation factor b (P-TEFb)-dependent manner. Little is known about the efficacy of activating HIV-1 reservoir cells under cART by BETi in vivo. In this study, we seek to test the potential of a BETi (I-BET151) in activating HIV-1 reservoir cells under effective cART in humanized mice in vivo. We discover that I-BET151 efficiently activates HIV-1 transcription in monocytic cells, but not in CD4+ T cells, during suppressive cART in vivo. We further reveal that HIV-1 proviruses in monocytic cells are more sensitive to I-BET151 treatment than in T cells in vitro. Finally, we demonstrate that I-BET151-activated viral transcription in monocytic cells is dependent on both CDK2 and CDK9, whereas only CDK9 is involved in activation of HIV-1 by I-BET151 in T cells. Our findings indicate a role of myeloid cells in HIV-1 persistence, and highlights the limitation of measuring or targeting T cell reservoirs alone in terms of HIV-1 cure, as well as provides a potential strategy to reactivate monocytic reservoirs during cART.\n\nIMPORTANCEIt has been reported the low level of active P-TEFb critically contributes to the maintenance of HIV-1 latency or low-replication in HIV-1 reservoir cells under cART. Bromodomain inhibitors are used to activate HIV-1 replication in vitro but their effect on activation of the HIV-1 resevoirs with cART in vivo is not clear. We found that BETi (I-BET151) treatment reactivated HIV-1 gene expression in humanized mice during suppressive cART. Interestingly, I-BET151 preferentially reactivated HIV-1 gene expression in monocytic cells, but not in CD4 T cells. Furthermore, I-BET151 significantly increased HIV-1 transcription in monocytic cells, but not in latently infected CD4 T cells, via CDK2-dependent mechanisms. Our findings suggest that BETi can preferentially activate monocytic HIV-1 reservoir cells, and a combination of latency reversal agents targeting different cell types and pathways is needed to achieve reactivation of different HIV-1 reservoir cells during cART.

immunology↗

bioRxiv2018

Costimulation through TLR2 drives polyfunctional CD8+ T cell responses

Optimal T cell activation requires antigen recognition through the T cell receptor (TCR), engagement of costimulatory molecules, and cytokines. T cells can also directly recognize danger signals through the expression of toll-like receptors (TLRs). Whether TLR ligands have the capacity to provide costimulatory signals and enhance antigen-driven T cell activation is not well understood. Here, we show that TLR2 and TLR7 ligands potently lower the antigen threshold for cytokine production in T cells. To investigate how TLR triggering supports cytokine production, we adapted the protocol for flow cytometry-based fluorescence in situ hybridization (Flow-FISH) to mouse T cells. The simultaneous detection of cytokine mRNA and protein with single-cell resolution revealed that TLR triggering primarily drives de novo mRNA transcription. Ifng mRNA stabilization only occurs when the TCR is engaged. TLR2, but not TLR7-mediated costimulation, can enhance mRNA stability at low antigen levels. Importantly, TLR2 costimulation increases the percentage of polyfunctional T cells, a hallmark of potent T cell responses. In conclusion, TLR-mediated costimulation effectively potentiates T cell effector function to suboptimal antigen levels.

immunology↗

bioRxiv2018

Absence of GdX/UBL4A protects against inflammatory bowel diseases by regulating NF-κB signaling in DCs and macrophages

Nuclear factor-kappa B (NF-{kappa}B) activation is critical for innate immune responses. Here we report that the UBL4A (Ubiquitin-like protein 4A, also named GdX) enhances dendritic cells (DCs) and macrophages (M{varphi})-mediated innate immune defenses by positively regulating NF-{kappa}B signaling. GdX-deficient mice were resistant to LPS-induced endotoxin shock and DSS-induced colitis. DC- or M{varphi}-specific GdX-deficient mice displayed alleviated mucosal inflammation, and the production of pro-inflammatory cytokines by GdX-deficient DCs and M{varphi} was reduced. Mechanistically, we found that PTPN2 (TC45) and PP2A form a complex with RelA (p65) to mediate its dephosphorylation whereas GdX interrupts the TC45/PP2A/p65 complex formation and restrict p65 dephosphorylation by trapping TC45. Our study provides a mechanism by which NF-{kappa}B signaling is positively regulated by an adaptor protein GdX in DC or M{varphi} to maintain the innate immune response. Targeting GdX could be a strategy to reduce over-activated immune response in inflammatory diseases.

immunology↗

bioRxiv2018

CryoEM structures of MDA5-dsRNA filaments at different stages of ATP hydrolysis

Double-stranded RNA (dsRNA) is a potent proinflammatory signature of viral infection. Long cytosolic dsRNA is recognized by MDA5. The cooperative assembly of MDA5 into helical filaments on dsRNA nucleates the assembly of a multiprotein type-I-interferon signaling platform. Here, we determined cryoEM structures of MDA5-dsRNA filaments with different helical twists and bound nucleotide analogs, at resolutions sufficient to build and refine atomic models. The structures identify the filament forming interfaces, which encode the dsRNA binding cooperativity and length specificity of MDA5. The predominantly hydrophobic interface contacts confer flexibility, reflected in the variable helical twist within filaments. Mutation of filament-forming residues can result in loss or gain of signaling activity. Each MDA5 molecule spans 14 or 15 RNA base pairs, depending on the twist. Variations in twist also correlate with variations in the occupancy and type of nucleotide in the active site, providing insights on how ATP hydrolysis contributes to MDA5-dsRNA recognition.\n\neTOCStructures of MDA5 bound to double-stranded RNA reveal a flexible, predominantly hydrophobic filament forming interface. The filaments have variable helical twist. Structures determined with ATP and transition state analogs show how the ATPase cycle is coupled to changes in helical twist, the mode of RNA binding and the length of the RNA footprint of MDA5.\n\nHighlightsO_LICryoEM structures of MDA5-dsRNA filaments determined for three catalytic states\nC_LIO_LIFilament forming interfaces are flexible and predominantly hydrophobic\nC_LIO_LIMutation of filament-forming residues can cause loss or gain of IFN-{beta} signaling\nC_LIO_LIATPase cycle is coupled to changes in filament twist and size of the RNA footprint\nC_LI

immunology↗

bioRxiv2018

Regulation of T cell expansion by antigen presentation dynamics

An essential feature of the adaptive immune system is the proliferation of antigen-specific lymphocytes during an immune reaction to form a large pool of effector cells. This proliferation must be regulated to ensure an effective response to infection while avoiding immunopathology. Recent experiments in mice have demonstrated that the expansion of a specific clone of T cells in response to cognate antigen obeys a striking inverse power law with respect to the initial number of T cells. Here, we show that such a relationship arises naturally from a model in which T cell expansion is limited by decaying levels of presented antigen. The same model also accounts for the observed dependence of T cell expansion on affinity for antigen and on the kinetics of antigen administration. Extending the model to address expansion of multiple T cell clones competing for antigen, we find that higher affinity clones can suppress the proliferation of lower affinity clones, thereby promoting the specificity of the response. Employing the model to derive optimal vaccination protocols, we find that exponentially increasing antigen doses can achieve a nearly optimized response. We thus conclude that the dynamics of presented antigen is a key regulator of both the size and specificity of the adaptive immune response.

immunology↗

bioRxiv2018

Homeostatic and Interferon-induced gene expression represent different states of promoter-associated transcription factor ISGF3

Cells maintain the balance between homeostasis and inflammation by adapting and integrating the activity of intracellular signalling cascades, including the JAK-STAT pathway. Our understanding how a tailored switch from homeostasis to a strong receptor-dependent response is coordinated remains limited. We used an integrated transcriptomic and proteomic approach to analyze transcription-factor binding, gene expression and in vivo proximity-dependent labelling of proteins in living cells under homeostatic and interferon (IFN)-induced conditions. We show that interferons (IFN) switch murine macrophages from resting-state to induced gene expression by alternating subunits of transcription factor ISGF3. Whereas preformed STAT2-IRF9 complexes control basal expression of IFN-induced genes (ISG), both type I IFN and, unexpectedly, IFN{gamma} cause promoter binding of a complete ISGF3 complex containing STAT1, STAT2 and IRF9. In contrast to the dogmatic view of ISGF3 formation in the cytoplasm, our results suggest a model wherein the assembly of the ISGF3 complex occurs on DNA.

immunology↗

bioRxiv2018

Sympatric and allopatric evolutionary contexts shape differential immune response in Biomphalaria / Schistosoma interaction

Selective pressures between hosts and their parasites can result in reciprocal evolution or adaptation of specific life history traits. Local adaptation of resident hosts and parasites should lead to host-parasite systems performing better in sympatry when compared to allopatry. Between-population variations in parasite infectivity/virulence and host defence/resistance, referred to as compatibility phenotype, were often the proxy used to analyse sympatric or allopatric adaptation. Nevertheless, some reported cases exist where allopatric host-parasite systems demonstrate compatibility phenotypes similar or greater than the one observed in sympatry. In these cases, the role of local adaptation is worth considering. Here, we study the interaction between Schistosoma and its vector snail Biomphalaria in which such a discrepancy in local versus foreign compatibility phenotype has been observed. Herein, we developed an integrative approach to investigate sympatric and allopatric interaction processes and link the underlying molecular mechanisms to the resulting phenotypes. Using comparative \"omics\" approaches joined to analysis of life history traits (immune cellular response, mortality, prevalence and compatibility) we tried to bridge the gap of knowledge that exists for connecting local adaptation observations to molecular phenotypes in Schistosoma/Biomphalaria interactions.\n\nWe found that despite displaying similar prevalence phenotypes, parasite infection triggered an immune suppression in snails living in sympatry, while it activated an immune response for those living in allopatry. Dual-comparative molecular analyses revealed that parasite infection causes immune suppression in sympatry. miRNAs were used to hijack the hosts immune response, allowing sympatric parasites to initiate their developmental program earlier and more efficiently.\n\nWe show that despite having similar prevalence phenotypes, sympatric and allopatric snail-Schistosoma interactions displayed a strongly different immunobiological molecular dialogue. The ability of allopatric pathogens to adapt rapidly and efficiently to new hosts could have critical consequences on disease emergence and risk of schistosomiasis outbreaks. These observations would have important consequences in term of schistosomiasis disease control.

immunology↗

bioRxiv2018

Differential T cell reactivity to hypocretin and flu antigen epitopes provides clues to the pathophysiology of Type 1 narcolepsy

Type 1 narcolepsy (T1N) is caused by hypocretin (HCRT) neuronal loss. Association with the Human Leukocyte Antigen (HLA)-DQB1*06:02/DQA1*01:02 (98% vs 25%) heterodimer (DQ0602), T cell receptor (TCR) and other immune loci suggest autoimmunity but autoantigen(s) are unknown. Onset is seasonal and associated with influenza A, notably pandemic 2009 H1N1 (pH1N1). An extensive unbiased DQ0602 binding peptide screen was performed encompassing peptides derived from Pandemrix(R) X-179-A pH1N1 influenza-A vaccine, a known T1N trigger, other H1N1 strains, and potential human autoantigens HCRT and RFX4, identifying 109 binders. The presence of cognate tetramer-peptide specific CD4+ T cells was studied in 35 narcolepsy cases and 22 DQ0602 controls after expansion of antigen-specific cells in Peripheral Blood Monocytes Cell (PBMC) cultures. Higher reactivity to influenza epitopes pHA273-287 (pH1N1 specific) and PR8 (H1N1 pre 2009)-specific NP17-31 were observed in T1N. Extensive reactivity to C-amidated but not native version of HCRT54-66 and HCRT86-97, which are two highly homologous peptides (HCRTNH2) was observed with higher frequencies of specific T cells in T1N. TCR/{beta} CDR3 sequences found in pHA273-287, NP17-31 and HCRTNH2 tetramer positive CD4+ cells were also retrieved in single INF{gamma}-secreting CD4+ sorted cells stimulated with Pandemrix(R), confirming immunodominance and functional significance in DQ0602-mediated responses and molecular mimicry. TCR/{beta} CDR3 motifs of HCRT54-66 and HCRT86-97 tetramers were extensively shared. Particularly notable was sharing across subjects of an CDR3, CAVETDSWGKLQF (in association with various CDR3{beta} that used TRAJ24, a chain modulated by Single Nucleotide Polymorphism (SNPs) rs1154155 and rs1483979 associated with T1N. Sharing of CDR3{beta} CASSQETQGRNYGYTF (in association with various CDR3 was also observed with HCRTNH2 and pHA273-287-tetramers across subjects. This segment uses TRBV4-2, a segment modulated by narcolepsy-associated SNP rs1008599. Higher HCRTNH2 positive CD4+ T cell numbers in T1N together with sharing of J24 CAVETDSWGKLQF in HCRTNH2 autoimmune responses, indicates causal DQ0602-mediated CD4+ autoreactivity to HCRT in T1N. Our results provide evidence for autoimmunity and molecular mimicry with flu antigens modulated by genetic components in the pathophysiology of T1N.

immunology↗

bioRxiv2018

PTGER2-β-Catenin Axis Links High Salt Environments to Autoimmunity by Balancing IFNγ and IL-10 in FoxP3+ Regulatory T cells

Foxp3+ regulatory T cells (Tregs) are the central component of peripheral immune tolerance. While dysregulation of the Treg cytokine signature has been observed in autoimmune diseases such as multiple sclerosis (MS) and type 1 diabetes, the regulatory mechanisms balancing pro- and anti-inflammatory cytokine production are not known. Here, we identify imbalance between IFN{gamma} and IL-10 as a shared Treg signature, present in patients with MS and under high salt conditions. By performing RNA-seq analysis on human Treg subpopulations, we identify {beta}-catenin as a key regulator that controls the expression of IFN{gamma} and IL-10. The activated {beta}-catenin signature is enriched specifically in IFN{gamma}+Tregs in humans, and this was confirmed in vivo with Treg-specific {beta}-catenin-stabilized mice exhibiting lethal autoimmunity with a dysfunctional, IFN{gamma}-producing, Treg phenotype. Moreover, we identify PTGER2 as a major factor balancing IFN{gamma} and IL-10 production in the context of a high salt environment, with skewed activation of the {beta}-catenin/SGK1/Foxo axis in IFN{gamma}+Tregs. These findings identify a novel molecular mechanism underlying inflammatory Tregs in human autoimmune disease and reveal a new role for a PTGER2-{beta}-catenin loop in Tregs linking environmental high salt conditions to autoimmunity.

immunology↗

bioRxiv2018

A Mouse Model Of Binge Alcohol Consumption and Burkholderia Infection

BackgroundBinge drinking, a common form of alcohol consumption, is associated with increased mortality and morbidity; yet, its effects on the immune systems ability to defend against infectious agents are poorly understood. Burkholderia pseudomallei, the causative agent of melioidosis can occur in healthy humans, yet binge alcohol use is progressively being recognized as a major risk factor. Although our previous studies demonstrated that binge alcohol exposure results in reduced alveolar macrophage function and increased Burkholderia virulence in vitro, no experimental studies have investigated the outcomes of binge alcohol on Burkholderia spp. infection in vivo.\n\nPrincipal FindingsWe used the close genetic relatives of B. pseudomallei, B. thailandensis E264 and B. vietnamiensis, as useful BSL-2 model systems. Eight-week-old female C57BL/6 mice were administered alcohol comparable to human binge drinking episodes (4.4 g/kg) or PBS intraperitoneally 30 min before a non-lethal intranasal infection. In an initial B. thailandensis infection (3 x 105), bacteria accumulated in the lungs and disseminated to the spleen in alcohol administered mice only, compared with PBS treated mice at 24 h post-infection (PI). The greatest bacterial load occurred with B. vietnamiensis (1 x 106) in lungs, spleen, and brain tissue by 72 h PI. Pulmonary cytokine expression (TNF-, GM-CSF) decreased, while splenic cytokine (IL-10) increased in binge drunk mice. Increased lung and brain permeability was observed as early as 2 h post alcohol administration in vivo. Trans-epithelial electrical resistance (TEER) was significantly decreased, while intracellular invasion of non-phagocytic cells increased with 0.2% v/v alcohol exposure in vitro.\n\nConclusionsOur results indicate that a single binge alcohol dose suppressed innate immune functions and increased the ability of less virulent Burkholderia strains to disseminate through increased barrier permeability and intracellular invasion of non-phagocytic cells.\n\nAuthor SummaryBurkholderia pseudomallei causes the disease melioidosis, which occurs in most tropical regions across the globe. Exposure rarely evolves to significant disease in the absence of specific comorbidities, such as binge alcohol intoxication. In susceptible hosts, the disease is primarily manifested as pneumonic melioidosis and can be rapidly fatal if untreated. In this study, we utilized B. thailandensis, a genetically similar strain to B. pseudomallei, and opportunistic B. vietnamiensis, a known human pathogen that utilizes similar virulence strategies as B. pseudomallei in immunocompromised and cystic fibrosis patients. The study investigates the impact of a single binge alcohol episode on infectivity and immune response in vivo. We show that a single binge alcohol episode prior to inhaling Burkholderia species increases bacterial spread to the lungs and brain. We also identify alcohol-induced tissue permeability and epithelial cell invasion as modes of action for greater bacterial spread and survival inside the host. Our results support the public health responses being developed in melioidosis-endemic regions that emphasize the nature of binge drinking as a prime concern, especially around potential times of exposure to environmental B. pseudomallei.

immunology↗

bioRxiv2018

Mucosal immunoglobulins protect the olfactory organ of teleost fish against parasitic infection

The olfactory organ of vertebrates receives chemical cues present in the air or water and, at the same time, they are exposed to invading pathogens. Nasal-associated lymphoid tissue (NALT), which serves as a mucosal inductive site for humoral immune responses against antigen stimulation, is present in teleosts and mammals. IgT in teleosts is responsible for similar functions to those carried by IgA in mammals. Moreover, teleost NALT is known to contain B-cells and teleost nasal mucus contains immunoglobulins (Igs). Yet, whether nasal B cells and Igs respond to infection remains unknown. We hypothesized that water-borne parasites can invade the nasal cavity of fish and elicit local specific immune responses. To address this hypothesis, we developed a model of bath infection with the Ichthyophthirius multifiliis (Ich) parasite in rainbow trout, Oncorhynchus mykiss, an ancient bony fish, and investigated the nasal adaptive immune response against this parasite. Critically, we found that Ich parasites in water could be reach the nasal cavity and successfully invade the nasal mucosa. Moreover, strong parasite-specific IgT responses were exclusively detected in the nasal mucus, and the accumulation of IgT+ B-cells was noted in the nasal epidermis after Ich infection. Strikingly, local IgT+ B-cell proliferation and parasite-specific IgT generation were found in the trout olfactory organ, providing new evidence that nasal-specific immune responses were induced locally by a parasitic challenge. Overall, our findings suggest that nasal mucosal adaptive immune responses are similar to those reported in other fish mucosal sites and that an antibody system with a dedicated mucosal Ig performs evolutionary conserved functions across vertebrate mucosal surfaces.\n\nAuthor SummaryThe olfactory organ is a vitally important chemosensory organ in vertebrates but it is also continuously stimulated by pathogenic microorganisms in the external environment. In mammals and birds, nasopharynx-associated lymphoid tissue (NALT) is considered the first line of immune defense against inhaled antigens and in bony fish, protecting against water-borne infections. However, although B-cells and immunoglobulins (Igs) have been found in teleost NALT, the defensive mechanisms of parasite-specific immune responses after pathogen challenge in the olfactory organ of teleost fish remain poorly understood. Considering that the NALT of all vertebrates has been subjected to similar evolutionary forces, we hypothesize that mucosal Igs play a critical role in the defense of olfactory systems against parasites. To confirm this hypothesis, we show the local proliferation of IgT+ B-cells and production of pathogen-specific IgT within the nasal mucosa upon parasite infection, indicating that parasite-specific IgT is the main Ig isotype specialized for nasal-adaptive immune responses. From an evolutionary perspective, our findings contribute to expanding our view of nasal immune systems and determining the fate of the host-pathogen interaction.

immunology↗

bioRxiv2018

IPSE, a urogenital parasite-derived immunomodulatory protein, ameliorates ifosfamide-induced hemorrhagic cystitis through downregulation of pro-inflammatory pathways

Ifosfamide and other oxazaphosphorines can result in hemorrhagic cystitis, a constellation of complications caused by acrolein metabolites. We previously showed that a single dose of IPSE, a schistosome-derived host modulatory protein, can ameliorate ifosfamide-related cystitis; however, the exact mechanisms underlying this urotoxic effect and its prevention are not fully understood. To provide insights into IPSEs protective mechanism, we undertook transcriptional profiling of bladders from ifosfamide-treated mice, with or without IPSE pretreatment. Following ifosfamide challenge, there was upregulation of a range of pro-inflammatory genes. The pro-inflammatory pathway involving the IL-1{beta}, TNF and IL-6 triad via NF{kappa}B and STAT3 signaling pathways was identified as the key driver of inflammation. The NRF2-mediated oxidative stress response pathway, which regulates both Hmox1-mediated heme homoeostasis and expression of antioxidant enzymes, was highly activated. Anti-inflammatory and cellular proliferation cascades implicated in tissue repair, namely Wnt, Hedgehog and PPAR pathways, were downregulated. IPSE administration before ifosfamide injection resulted in significant downregulation of major proinflammatory pathways including the triad of IL-1{beta}, TNF and IL-6 pathways, the interferon signaling pathway, and less apparent reduction in oxidative stress responses. Taken together, we have identified signatures of acute phase inflammation and oxidative stress responses in the ifosfamide-injured bladder, which are reversed by pretreatment with IPSE, a parasite derived anti-inflammatory molecule. In addition to providing new insights into the underlying mechanism of IPSEs therapeutic effects, this work has revealed several pathways that could be therapeutically targeted to prevent and treat ifosfamide-induced hemorrhagic cystitis.

immunology↗

bioRxiv2018

Insights from Comparison of the Renal and Skin Single Cell Transcriptomes in Lupus Nephritis

Lupus nephritis (LN) occurs in up to 50% of patients with systemic lupus erythematosus (SLE), and is a major contributor to mortality and morbidity. LN presents as a highly heterogeneous disease both in histopathology and response to therapy. The molecular and cellular processes leading to renal damage and to the heterogeneity of the disease are not well understood. To elucidate the processes underpinning the heterogeneity of LN, we applied singlecell RNA-sequencing (scRNA-seq) to renal biopsies from LN patients. Skin biopsies were evaluated as a source of biomarkers for monitoring kidney disease. Type-I interferon (IFN) response signatures were identified in tubular cells and keratinocytes, differentiating LN patients from healthy controls. Non-responders associated with higher IFN signatures in both tissue compartments. Moreover, non-response was also associated with a fibrotic signature in the tubular cells. Receptor-ligand interaction analysis indicated that the fibrotic process is likely mediated by FGF receptors with the initiating signal originating from infiltrating leukocytes. Differential expression analysis of tubular cells between proliferative and membranous LN pointed to several fibrosis-relevant pathways, which may offer insight into their histological differences. In summary, scRNA-seq was applied to LN to deconstruct its heterogeneity and provide novel targets for personalized approaches to therapy.

immunology↗