Trim21 deficiency in mice increases HCC carcinogenesis in a NASH context and is associated with immune checkpoint upregulation.

The global pandemic of metabolic diseases has increased the incidence of hepatocellular carcinoma (HCC) in the context of non-alcoholic steatohepatitis (NASH). The downregulation of the E3 ubiquitin ligase TRIM21 has been linked to poor prognosis in different cancers including HCC. In order to investigate the role of TRIM21 in liver cancer progression on NASH, Trim21+/+ and Trim21-/- male mice were injected with streptozotocin at the neonatal stage. The hypoinsulinemic mice were then fed with a high-fat high-cholesterol diet (HFHCD) for 4, 8 or 12 weeks. All mice developed NASH which systematically resulted in HCC progression. Interestingly, compared to the Trim21+/+ control mice, liver damage was worsened in Trim21-/- mice, with more HCC nodules found after 12 weeks on HFHCD. Immune population analysis in the spleen and liver revealed a higher proportion of CD4+PD-1+ and CD8+PD-1+ T cells in Trim21-/- mice. The liver and HCC tumors of Trim21-/- mice also exhibited an increase in the number of PD-L1+ and CD68+ PD-L1+ cells. Thus, TRIM21 limits the emergence of HCC nodules in mice with NASH by potentially restricting the expression of PD-1 in lymphocytes and PD-L1 in tumors.

Developing a rigorous, systematic methodology to identify and categorize elder mistreatment in criminal justice data.

Elder mistreatment is complex, with cases typically requiring integrated responses from social services, medicine, civil law, and criminal justice. Only limited research exists describing elder mistreatment prosecution and its impact. Researchers have not yet examined administrative prosecutorial data to explore mistreatment response, and no standardized analytic approach exists. We developed a rigorous, systematic methodologic approach to identify elder mistreatment cases in prosecutorial data from cases of crimes against victims aged ≥60. To do so, we operationalized elements of the accepted definition of elder mistreatment, including expectation of trust and vulnerability. We also designed an approach to categorize elder mistreatment cases, using the types of charges filed, into: financial exploitation, physical abuse, sexual abuse, verbal/emotional/psychological abuse, and neglect. This standardized methodological approach to identify and categorize elder mistreatment cases in prosecution data is an important preliminary step in analyzing this potentially untapped source of useful information about mistreatment response.

Criteria to Screen for Traumatic Cervical Spine Instability: A Consensus of Chiropractic Radiologists.

OBJECTIVE: The purpose of this study was to establish consensus on a radiographic definition for cervical instability for routine use in chiropractic patients who sustain trauma to the cervical spine. METHOD: We conducted a modified Delphi study with a panel of chiropractic radiologists. Panelists were asked to rate potential screening criteria for traumatic cervical spine instability when assessing cervical spine radiographs. Items rated as important for inclusion by at least 60% of participants in round 1 were submitted for a second round of voting in round 2. Items rated for inclusion by at least 75% of the participants in round 2 were used to create the consensus-based list of screening criteria. Participants were asked to vote and reach agreement on the final screening criteria list in round 3. RESULTS: Twenty-nine chiropractic radiologists participated in round 1. After 3 rounds of survey, 85% of participants approved the final consensus-based list of criteria for traumatic cervical spine instability screening, including 6 clinical signs and symptoms and 5 radiographic criteria. Participants agreed that the presence of 1 or more of these clinical signs and symptoms and/or 1 or more of the 5 radiographic criteria on routine static radiographic studies suggests cervical instability. CONCLUSION: The consensus-based radiographic definition of traumatic cervical spine instability includes 6 clinical signs and symptoms and 5 radiographic criteria that doctors of chiropractic should apply to their patients who sustain trauma to the cervical spine.

RIPK1 protects hepatocytes from Kupffer cells-mediated TNF-induced apoptosis in mouse models of PAMP-induced hepatitis.

BACKGROUND & AIMS: The severity of liver diseases is exacerbated by the death of hepatocytes, which can be induced by the sensing of pathogen associated molecular patterns (PAMPs) derived from the gut microbiota. The molecular mechanisms regulating these cell death pathways are poorly documented. In this study, we investigated the role of the receptor interacting protein kinase 1 (RIPK1), a protein known to regulate cell fate decisions, in the death of hepatocytes using two in vivo models of PAMP-induced hepatitis. METHODS: Hepatitis was induced in mice by independent injections of two different bacterial PAMPs: lipopolysaccharide (LPS) and unmethylated CpG oligodeoxynucleotide (CpG-DNA) motifs. The role of RIPK1 was evaluated by using mice specifically lacking RIPK1 in liver parenchymal cells (Ripk1LPC-KO). Administration of liposome-encapsulated clodronate served to investigate the role of Kupffer cells in the establishment of the disease. Etanercept, a tumor necrosis factor (TNF)-decoy receptor, was used to study the contribution of TNF-α during LPS-mediated liver injury. RESULTS: Whereas RIPK1 deficiency in liver parenchymal cells did not trigger basal hepatolysis, it greatly sensitized hepatocytes to apoptosis and liver damage following a single injection of LPS or CpG-DNA. Importantly, hepatocyte death was prevented by previous macrophage depletion or by TNF inhibition. CONCLUSIONS: Our data highlight the pivotal function of RIPK1 in maintaining liver homeostasis in conditions of macrophage-induced TNF burst in response to PAMPs sensing. LAY SUMMARY: Excessive death of hepatocytes is a characteristic of liver injury. A new programmed cell death pathway has been described involving upstream death ligands such as TNF and downstream kinases such as RIPK1. Here, we show that in the presence of LPS liver induced hepatic injury was due to secretion of TNF by liver macrophages, and that RIPK1 acts as a powerful protector of hepatocyte death. This newly identified pathway in the liver may be helpful in the management of patients to predict their risk of developing acute liver failure.

PARP2 deficiency affects invariant-NKT-cell maturation and protects mice from concanavalin A-induced liver injury.

Excessive or persistent inflammation and hepatocyte death are the key triggers of liver diseases. The poly(ADP-ribose) polymerase (PARP) proteins induce cell death and inflammation. Chemical inhibition of PARP activity protects against liver injury during concanavalin A (ConA)-induced hepatitis. In this mice model, ConA activates immune cells, which promote inflammation and induce hepatocyte death, mediated by the activated invariant natural killer T (iNKT) lymphocyte population. We analyzed immune cell populations in the liver and several lymphoid organs, such as the spleen, thymus, and bone marrow in Parp2-deficient mice to better define the role of PARP proteins in liver immunity and inflammation at steady state and during ConA-induced hepatitis. We show that 1) the genetic inactivation of Parp2, but not Parp1, protected mice from ConA hepatitis without deregulating cytokine expression and leucocyte recruitment; 2) cellularity was lower in the thymus, but not in spleen, liver, or bone marrow of Parp2-/- mice; 3) spleen and liver iNKT lymphocytes, as well as thymic T and NKT lymphocytes were reduced in Parp2 knockout mice. In conclusion, our results suggest that the defect of T-lymphocyte maturation in Parp2 knockout mice leads to a systemic reduction of iNKT cells, reducing hepatocyte death during ConA-mediated liver damage, thus protecting the mice from hepatitis.NEW & NOTEWORTHY The genetic inactivation of Parp2, but not Parp1, protects mice from concanavalin A hepatitis. Immune cell populations are lower in the thymus, but not in the spleen, liver, or bone marrow of Parp2-deficient mice compared with wild-type mice. Spleen and liver invariant natural killer T (NKT) lymphocytes, as well as thymic T and NKT lymphocytes, are reduced in Parp2-deficient mice.

The Effectiveness of Exercise on Recovery and Clinical Outcomes in Patients With Soft Tissue Injuries of the Hip, Thigh, or Knee: A Systematic Review by the Ontario Protocol for Traffic Injury Management (OPTIMa) Collaboration.

OBJECTIVE: The purpose of this systematic review was to determine the effectiveness of exercise for the management of soft tissue injuries of the hip, thigh, and knee. METHODS: We conducted a systematic review and searched MEDLINE, EMBASE, PsycINFO, the Cochrane Central Register of Controlled Trials, and CINAHL Plus with Full Text from January 1, 1990, to April 8, 2015, for randomized controlled trials (RCTs), cohort studies, and case-control studies evaluating the effect of exercise on pain intensity, self-rated recovery, functional recovery, health-related quality of life, psychological outcomes, and adverse events. Random pairs of independent reviewers screened titles and abstracts and assessed risk of bias using the Scottish Intercollegiate Guidelines Network criteria. Best evidence synthesis methodology was used. RESULTS: We screened 9494 citations. Eight RCTs were critically appraised, and 3 had low risk of bias and were included in our synthesis. One RCT found statistically significant improvements in pain and function favoring clinic-based progressive combined exercises over a "wait and see" approach for patellofemoral pain syndrome. A second RCT suggests that supervised closed kinetic chain exercises may lead to greater symptom improvement than open chain exercises for patellofemoral pain syndrome. One RCT suggests that clinic-based group exercises may be more effective than multimodal physiotherapy in male athletes with persistent groin pain. CONCLUSION: We found limited high-quality evidence to support the use of exercise for the management of soft tissue injuries of the lower extremity. The evidence suggests that clinic-based exercise programs may benefit patients with patellofemoral pain syndrome and persistent groin pain. Further high-quality research is needed.

TG1050, an immunotherapeutic to treat chronic hepatitis B, induces robust T cells and exerts an antiviral effect in HBV-persistent mice.

OBJECTIVE: To assess a new adenovirus-based immunotherapy as a novel treatment approach to chronic hepatitis B (CHB). METHODS: TG1050 is a non-replicative adenovirus serotype 5 encoding a unique large fusion protein composed of a truncated HBV Core, a modified HBV Polymerase and two HBV Envelope domains. We used a recently described HBV-persistent mouse model based on a recombinant adenovirus-associated virus encoding an over length genome of HBV that induces the chronic production of HBsAg, HBeAg and infectious HBV particles to assess the ability of TG1050 to induce functional T cells in face of a chronic status. RESULTS: In in vitro studies, TG1050 was shown to express the expected large polyprotein together with a dominant, smaller by-product. Following a single administration in mice, TG1050 induced robust, multispecific and long-lasting HBV-specific T cells detectable up to 1 year post-injection. These cells target all three encoded immunogens and display bifunctionality (i.e., capacity to produce both interferon γ and tumour necrosis factor α as well as cytolytic functions). In addition, control of circulating levels of HBV DNA and HBsAg was observed while alanine aminotransferase levels remain in the normal range. CONCLUSIONS: Injection of TG1050 induced both splenic and intrahepatic functional T cells producing cytokines and displaying cytolytic activity in HBV-naïve and HBV-persistent mouse models together with significant reduction of circulating viral parameters. These results warrant clinical evaluation of TG1050 in the treatment of CHB.

HBx relieves chromatin-mediated transcriptional repression of hepatitis B viral cccDNA involving SETDB1 histone methyltransferase.

BACKGROUND & AIMS: Maintenance of the covalently closed circular HBV DNA (cccDNA) that serves as a template for HBV transcription is responsible for the failure of antiviral therapies. While studies in chronic hepatitis patients have shown that high viremia correlates with hyperacetylation of cccDNA-associated histones, the molecular mechanisms controlling cccDNA stability and transcriptional regulation are still poorly understood. This study aimed to decipher the role of chromatin and chromatin modifier proteins on HBV transcription. METHODS: We analyzed the chromatin structure of actively transcribed or silenced cccDNA by infecting primary human hepatocytes and differentiated HepaRG cells with wild-type virus or virus deficient (HBVX-) for the expression of hepatitis B virus X protein (HBx), that is required for HBV expression. RESULTS: In the absence of HBx, HBV cccDNA was transcriptionally silenced with the concomitant decrease of histone 3 (H3) acetylation and H3K4me3, increase of H3 di- and tri-methylation (H3K9me) and the recruitment of heterochromatin protein 1 factors (HP1) that correlate with condensed chromatin. SETDB1 was found to be the main histone methyltransferase responsible for the deposition of H3K9me3 and HBV repression. Finally, full transcriptional reactivation of HBVX- upon HBx re-expression correlated with an increase of histone acetylation and H3K4me3, and a concomitant decrease of HP1 binding and of H3K9me3 on the cccDNA. CONCLUSION: Upon HBV infection, cellular mechanisms involving SETDB1-mediated H3K9me3 and HP1 induce silencing of HBV cccDNA transcription through modulation of chromatin structure. HBx is able to relieve this repression and allow the establishment of active chromatin.

The effectiveness of passive physical modalities for the management of soft tissue injuries and neuropathies of the wrist and hand: a systematic review by the Ontario Protocol for Traffic Injury Management (OPTIMa) collaboration.

OBJECTIVE: The purpose of this systematic review was to determine the effectiveness of passive physical modalities compared to other interventions, placebo/sham interventions, or no intervention in improving self-rated recovery, functional recovery, clinical outcomes and/or administrative outcomes (eg, time of disability benefits) in adults and/or children with soft tissue injuries and neuropathies of the wrist and hand. METHODS: We systematically searched MEDLINE, EMBASE, PsycINFO, and the Cochrane Central Register of Controlled Trials, accessed through Ovid Technologies, Inc, and CINAHL Plus with Full Text, accessed through EBSCO host, from 1990 to 2015. Our search strategies combined controlled vocabulary relevant to each database (eg, MeSH for MEDLINE) and text words relevant to our research question and the inclusion criteria. Randomized controlled trials, cohort studies, and case-control studies were eligible. Random pairs of independent reviewers screened studies for relevance and critically appraised relevant studies using the Scottish Intercollegiate Guidelines Network criteria. Studies with low risk of bias were synthesized following best evidence synthesis principles. RESULTS: We screened 6618 articles and critically appraised 11 studies. Of those, 7 had low risk of bias: 5 addressed carpal tunnel syndrome (CTS) and 2 addressed de Quervain disease. We found evidence that various types of night splints lead to similar outcomes for the management of CTS. The evidence suggests that a night wrist splint is less effective than surgery in the short term but not in the long term. Furthermore, a night wrist splint and needle electroacupuncture lead to similar outcomes immediately postintervention. Finally, low-level laser therapy and placebo low-level laser therapy lead to similar outcomes. The evidence suggests that kinesio tape or a thumb spica cast offers short-term benefit for the management of de Quervain disease. Our search did not identify any low risk of bias studies examining the effectiveness of passive physical modalities for the management of other soft tissue injuries or neuropathies of the wrist and hand. CONCLUSIONS: Different night orthoses provided similar outcomes for CTS. Night orthoses offer similar outcomes to electroacupuncture but are less effective than surgery in the short term. This review suggests that kinesio tape or a thumb spica cast may offer short-term benefit for the management of de Quervain disease.

The effectiveness of exercise for the management of musculoskeletal disorders and injuries of the elbow, forearm, wrist, and hand: a systematic review by the Ontario Protocol for Traffic Injury Management (OPTIMa) collaboration.

OBJECTIVE: The purpose of this systematic review was to evaluate the effectiveness of exercise compared to other interventions, placebo/sham intervention, or no intervention in improving self-rated recovery, functional recovery, clinical, and/or administrative outcomes in individuals with musculoskeletal disorders and injuries of the elbow, forearm, wrist, and hand. METHODS: We searched MEDLINE, EMBASE, CINAHL, PsycINFO, and the Cochrane Central Register of Controlled Trials from 1990 to 2015. Paired reviewers independently screened studies for relevance and assessed the risk of bias using the Scottish Intercollegiate Guidelines Network criteria. We synthesized the evidence using the best evidence synthesis methodology. RESULTS: We identified 5 studies with a low risk of bias. Our review suggests that, for patients with persistent lateral epicondylitis, (1) adding concentric or eccentric strengthening exercises to home stretching exercises provides no additional benefits; (2) a home program of either eccentric or concentric strengthening exercises leads to similar outcomes; (3) home wrist extensor strengthening exercises lead to greater short-term improvements in pain reduction compared to "wait and see"; and (4) clinic-based, supervised exercise may be more beneficial than home exercises with minimal improvements in pain and function. For hand pain of variable duration, supervised progressive strength training added to advice to continue normal physical activity provides no additional benefits. CONCLUSION: The relative effectiveness of stretching vs strengthening for the wrist extensors remains unknown for the management of persistent lateral epicondylitis. The current evidence shows that the addition of supervised progressive strength training does not provide further benefits over advice to continue normal physical activity for hand pain of variable duration.

Adeno-associated virus-mediated gene transfer leads to persistent hepatitis B virus replication in mice expressing HLA-A2 and HLA-DR1 molecules.

Hepatitis B virus (HBV) persistence may be due to impaired HBV-specific immune responses being unable to eliminate efficiently or cure infected hepatocytes. The immune mechanisms that lead to HBV persistence have not been completely identified, and no appropriate animal model is available for such studies. Therefore, we established a chronic HBV infection model in a mouse strain with human leukocyte antigen A2/DR1 (HLA-A2/DR1) transgenes and an H-2 class I/class II knockout. The liver of these mice was transduced with adeno-associated virus serotype 2/8 (AAV2/8) carrying a replication-competent HBV DNA genome. In all AAV2/8-transduced mice, hepatitis B virus surface antigen, hepatitis B virus e antigen, and HBV DNA persisted in serum for at least 1 year. Viral replication intermediates and transcripts were detected in the livers of the AAV-injected mice. The hepatitis B core antigen was expressed in 60% of hepatocytes. No significant inflammation was observed in the liver. This was linked to a higher number of regulatory T cells in liver than in controls and a defect in HBV-specific functional T-cell responses. Despite the substantial tolerance resulting from expression of HBV antigens in hepatocytes, we succeeded in priming functional HBV-specific T-cell responses in peripheral tissues, which subsequently reached the liver. This AAV2/8-HBV-transduced HLA-A2/DR1 murine model recapitulates virological and immunological characteristics of chronic HBV infection, and it could be useful for the development of new treatments and immune-based therapies or therapeutic vaccines for chronic HBV infections.

Methyltransferase PRMT1 is a binding partner of HBx and a negative regulator of hepatitis B virus transcription.

The hepatitis B virus X protein (HBx) is essential for virus replication and has been implicated in the development of liver cancer. HBx is recruited to viral and cellular promoters and activates transcription by interacting with transcription factors and coactivators. Here, we purified HBx-associated factors in nuclear extracts from HepG2 hepatoma cells and identified protein arginine methyltransferase 1 (PRMT1) as a novel HBx-interacting protein. We showed that PRMT1 overexpression reduced the transcription of hepatitis B virus (HBV), and this inhibition was dependent on the methyltransferase function of PRMT1. Conversely, depletion of PRMT1 correlated with increased HBV transcription. Using a quantitative chromatin immunoprecipitation assay, we found that PRMT1 is recruited to HBV DNA, suggesting a direct effect of PRMT1 on the regulation of HBV transcription. Finally, we showed that HBx expression inhibited PRMT1-mediated protein methylation. Downregulation of PRMT1 activity was further observed in HBV-replicating cells in an in vivo animal model. Altogether, our results support the notion that the binding of HBx to PRMT1 might benefit viral replication by relieving the inhibitory activity of PRMT1 on HBV transcription.

Caregiver burden: a clinical review.

IMPORTANCE: Caregiver burden may result from providing care for patients with chronic illness. It can occur in any of the 43.5 million individuals providing support to midlife and older adults. Caregiver burden is frequently overlooked by clinicians. OBJECTIVES: To outline the epidemiology of caregiver burden; to provide strategies to diagnose, assess, and intervene for caregiver burden in clinical practice; and to evaluate evidence on interventions intended to avert or mitigate caregiver burden and related caregiver distress. EVIDENCE: Cohort studies examining the relation between demographic and social risk factors and adverse outcomes of caregiver burden were reviewed. Review of recent meta-analyses to summarize the effectiveness of caregiver burden interventions were identified by searching Ovid MEDLINE, AgeLine, and the Cochrane Library. RESULTS: Risk factors for caregiver burden include female sex, low educational attainment, residence with the care recipient, higher number of hours spent caregiving, depression, social isolation, financial stress, and lack of choice in being a caregiver. Practical assessment strategies for caregiver burden exist to evaluate caregivers, their care recipients, and the care recipient's overall caregiving needs. A variety of psychosocial and pharmacological interventions have shown mild to modest efficacy in mitigating caregiver burden and associated manifestations of caregiver distress in high-quality meta-analyses. Psychosocial interventions include support groups or psychoeducational interventions for caregivers of dementia patients (effect size, 0.09-0.23). Pharmacologic interventions include use of anticholinergics or antipsychotic medications for dementia or dementia-related behaviors in the care recipient (effect size, 0.18-0.27). Many studies showed improvements in caregiver burden-associated symptoms (eg, mood, coping, self-efficacy) even when caregiver burden itself was minimally improved. CONCLUSIONS AND RELEVANCE: Physicians have a responsibility to recognize caregiver burden. Caregiver assessment and intervention should be tailored to the individual circumstances and contexts in which caregiver burden occurs.

Alveolar echinococcosis in immunocompromised hosts.

BACKGROUND: Alveolar echinococcosis (AE) results of an infection with the larval stage of Echinococcus multilocularis. It has been increasingly described in individuals with impaired immune responsiveness. OBJECTIVES: This narrative review aims at describing the presentation of AE according to the type of immune impairment, based on retrospective cohorts and case reports. Implications for patient management and future research are proposed accordingly. SOURCES: Targeted search was conducted in PubMed using ((alveolar echinococcosis) OR (multilocularis)) AND ((immunosuppressive) OR (immunodeficiency) OR (AIDS) OR (solid organ transplant) OR (autoimmunity) OR (immune deficiency)). Only publications in English were considered. CONTENT: Seventeen publications were found, including 13 reports of 55 AE in immunocompromised patients (AE/IS) and 4 retrospective studies of 755 AE immunocompetent patients and 115 AE/IS (13%). The cohorts included 9 (1%) solid organ transplantation (SOT) recipients, 2 (0.2%) HIV patients, 41 (4.7%) with chronic inflammatory/autoimmune diseases (I/AID) and 72 (8.3%) with malignancies. SOT, I/AID and malignancies, but not HIV infection, were significantly associated with AE (odds ratios of 10.8, 1.6, 5.9, and 1.3, respectively). Compared to AE immunocompetent patients, AE/IS was associated with earlier diagnosis (PNM stages I-II: 49/85 (58%) vs. 137/348 (39%), p < 0.001), high rate of atypical imaging (24/50 (48%) vs. 106/375 (28%), p < 0.01), and low sensitivity of serology (19/77 (25%) vs. 265/329 (81%), p < 0.001). Unusually extensive or disseminated infections were described in SOT and I/AID patients. IMPLICATIONS: Patients who live in endemic areas should benefit from serology before onset of a long-term immunosuppressive therapy, even if the cost-benefit ratio has to be evaluated. Physicians should explain AE to immunocompromised patients and think about AE when finding a liver lesion. Further research should address gaps in knowledge of AE/IS. Especially, extensive and accurate records of AE cases have to be collected by multinational registries.

Endogenous IL-33 Accelerates Metacestode Growth during Late-Stage Alveolar Echinococcosis.

During the course of the infectious disease alveolar echinococcosis (AE), the larval stage of Echinococcus multilocularis develops in the liver, where an initial Th1/Th17 immune response may allow its elimination in resistant individuals. In patients susceptible to infection and disease, the Th2 response initiates later, inducing tolerance to the parasite. The role of interleukin 33 (IL-33), an alarmin released during necrosis and known to drive a Th2 immune response, has not yet been described during AE. Wild-type (WT) and IL-33-/- C57BL/6J mice were infected by peritoneal inoculation with E. multilocularis metacestodes and euthanized 4 months later, and their immune response were analyzed. Immunofluorescence staining and IL-33 enzyme-linked immunosorbent assay (ELISA) were also performed on liver samples from human patients with AE. Overall, metacestode lesions were smaller in IL-33-/- mice than in WT mice. IL-33 was detected in periparasitic tissues, but not in mouse or human serum. In infected mice, endogenous IL-33 modified peritoneal macrophage polarization and cytokine profiles. Th2 cytokine concentrations were positively correlated with parasite mass in WT mice, but not in IL-33-/- mice. In human AE patients, IL-33 concentrations were higher in parasitic tissues than in distant liver parenchyma. The main sources of IL-33 were CD31+ endothelial cells of the neovasculature, present within lymphoid periparasitic infiltrates together with FOXP3+ Tregs. In the murine model, periparasitic IL-33 correlated with accelerated parasite growth putatively through the polarization of M2-like macrophages and release of immunosuppressive cytokines IL-10 and transforming growth factor ß1 (TGF-ß1). We concluded that IL-33 is a key alarmin in AE that contributes to the tolerogenic effect of systemic Th2 cytokines. IMPORTANCE Infection with the metacestode stage of Echinococcus multilocularis, known as alveolar echinococcosis, is the most severe cestodosis worldwide. However, less than 1% of exposed individuals, in which the immune system is unable to control the parasite, develop the disease. The factors responsible for this interindividual variability are not fully understood. In this in vivo study comparing wild-type and IL-33-/- infected mice, together with data from human clinical samples, we determined that IL-33, an alarmin released following tissue injury and involved in the pathogenesis of cancer and asthma, accelerates the progression of the disease by modulating the periparasitic microenvironment. This suggests that targeting IL-33 could be of interest for the management of patients with AE, and that IL-33 polymorphisms could be responsible for increased susceptibility to AE.

Deciphering the Role of PIG1 and DHN-Melanin in Scedosporium apiospermum Conidia.

Scedosporium apiospermum is a saprophytic filamentous fungus involved in human infections, of which the virulence factors that contribute to pathogenesis are still poorly characterized. In particular, little is known about the specific role of dihydroxynaphtalene (DHN)-melanin, located on the external layer of the conidia cell wall. We previously identified a transcription factor, PIG1, which may be involved in DHN-melanin biosynthesis. To elucidate the role of PIG1 and DHN-melanin in S. apiospermum, a CRISPR-Cas9-mediated PIG1 deletion was carried out from two parental strains to evaluate its impact on melanin biosynthesis, conidia cell-wall assembly, and resistance to stress, including the ability to survive macrophage engulfment. ΔPIG1 mutants did not produce melanin and showed a disorganized and thinner cell wall, resulting in a lower survival rate when exposed to oxidizing conditions, or high temperature. The absence of melanin increased the exposure of antigenic patterns on the conidia surface. PIG1 regulates the melanization of S. apiospermum conidia, and is involved in the survival to environmental injuries and to the host immune response, that might participate in virulence. Moreover, a transcriptomic analysis was performed to explain the observed aberrant septate conidia morphology and found differentially expressed genes, underlining the pleiotropic function of PIG1.

Receptor-interacting protein kinase-1 ablation in liver parenchymal cells promotes liver fibrosis in murine NASH without affecting other symptoms.

Non-alcoholic steatohepatitis (NASH), a chronic liver disease that emerged in industrialized countries, can further progress into liver fibrosis, cirrhosis, and hepatocellular carcinoma. In the next decade, NASH is predicted to become the leading cause of liver transplantation, the only current interventional therapeutic option. Hepatocyte death, triggered by different death ligands, plays key role in its progression. Previously, we showed that the receptor-interacting protein kinase-1 (RIPK1) in hepatocytes exhibits a protective role in ligand-induced death. Now, to decipher the role of RIPK1 in NASH, Ripk1LPC-KO mice, deficient for RIPK1 only in liver parenchymal cells, and their wild-type littermates (Ripk1fl/fl) were fed for 3, 5, or 12 weeks with high-fat high-cholesterol diet (HFHCD). The main clinical signs of NASH were analyzed to compare the pathophysiological state established in mice. Most of the symptoms evolved similarly whatever the genotype, whether it was the increase in liver to body weight ratio, the steatosis grade or the worsening of liver damage revealed by serum transaminase levels. In parallel, inflammation markers followed the same kinetics with significant equivalent inductions of cytokines (hepatic mRNA levels and blood cytokine concentrations) and a main peak of hepatic infiltration of immune cells at 3 weeks of HFHCD. Despite this identical inflammatory response, more hepatic fibrosis was significantly evidenced at week 12 in Ripk1LPC-KO mice. This coincided with over-induced rates of transcripts of genes implied in fibrosis development (Tgfb1, Tgfbi, Timp1, and Timp2) in Ripk1LPC-KO animals. In conclusion, our results show that RIPK1 in hepatocyte limits the progression of liver fibrosis during NASH.

Bacteroides fragilis derived metabolites, identified by molecular networking, decrease Salmonella virulence in mice model.

In the gut microbiota, resident bacteria prevent pathogens infection by producing specific metabolites. Among bacteria belonging to phylum Bacteroidota, we have previously shown that Bacteroides fragilis or its cell-free supernatant inhibited in vitro Salmonella Heidelberg translocation. In the present study, we have analyzed this supernatant to identify bioactive molecules after extraction and subsequent fractionation using a semi-preparative reversed-phase Liquid Chromatography High-Resolution Tandem Mass Spectrometry (LC-HRMS/MS). The results indicated that only two fractions (F3 and F4) strongly inhibited S. Heidelberg translocation in a model mimicking the intestinal epithelium. The efficiency of the bioactive fractions was evaluated in BALB/c mice, and the results showed a decrease of S. Heidelberg in Peyer's patches and spleen, associated with a decrease in inflammatory cytokines and neutrophils infiltration. The reduction of the genus Alistipes in mice receiving the fractions could be related to the anti-inflammatory effects of bioactive fractions. Furthermore, these bioactive fractions did not alter the gut microbiota diversity in mice. To further characterize the compounds present in these bioactive fractions, Liquid Chromatography High-Resolution Tandem Mass Spectrometry (LC-HRMS/MS) data were analyzed through molecular networking, highlighting cholic acid (CA) and deoxycholic acid. In vitro, CA had inhibitory activity against the translocation of S. Heidelberg by significantly decreasing the expression of Salmonella virulence genes such as sipA. The bioactive fractions also significantly downregulated the flagellar gene fliC, suggesting the involvement of other active molecules. This study showed the interest to characterize better the metabolites produced by B. fragilis to make them means of fighting pathogenic bacteria by targeting their virulence factor without modifying the gut microbiota.

Protection against lethal Neospora caninum infection in mice induced by heterologous vaccination with a mic1 mic3 knockout Toxoplasma gondii strain.

Neospora caninum and Toxoplasma gondii are closely related, obligate intracellular parasites infecting a wide range of vertebrate hosts and causing abortion and neonatal morbidity and mortality. Several lines of evidence suggest that cross immunity between these two pathogens could be exploited in the design of strategies for heterologous vaccination. We assessed the ability of an attenuated strain of T. gondii ("mic1-3KO strain") conferring strong protection against chronic and congenital toxoplasmosis to protect mice against lethal N. caninum infection. Mice immunized with mic1-3KO tachyzoites by the oral and intraperitoneal routes developed a strong cellular Th1 response and displayed significant protection against lethal heterologous N. caninum infection, with survival rates of 70% and 80%, respectively, whereas only 30% of the nonimmunized mice survived. We report here the acquisition of heterologous protective immunity against N. caninum following immunization with a live attenuated mic1-3KO strain of T. gondii.

IL-33/ST2 axis is involved in disease progression in the spleen during Leishmania donovani infection.

BACKGROUND: During infection with Leishmania donovani, parasite control is linked to the systemic Th1 immune response, but in infected organs (liver, spleen and bone marrow), the response differs according to the micro-environment. The pleiomorphic cytokine interleukin-33 (IL-33) exerts various roles during infection, either protective or detrimental. In this study, we explored the role of IL-33 in the outcome of Leishmania infection in the spleen. METHODS: We used several mouse models, on BALB/c and C57BL/6 (B6) backgrounds, infected with L. donovani and sacrificed at 15, 30 or 60 days after infection and characterized mRNA expression of immune markers, immune cell populations, histological response, and parasite loads. RESULTS: During infection IL-33 and ST2 mRNA increased in parallel in the spleen of wild type (wt) animals and paralleled the immunodetection of ST2+ and IL-33+ cells; their expression was twice as high in BALB/c, compared to B6 mice. Mice treated with twice-weekly injections of rIL-33 had higher splenic parasite burdens on D15 (BALB/c) or on D60 (B6). In BALB/c, IL-33 treatment led to immune exhaustion with abolition of Th1 cytokine expression (IFN-γ and IL-12) in the spleen and higher serum levels of Th2 cytokines (IL-4, IL-5 and IL-13). In B6, IL-33 treatment induced the Treg cell pathway with a dramatic increase of FoxP3 mRNA induction and expression on tissue sections. IL-33-KO mice had lower parasite loads and a higher Th1 response than their wt counterparts. CONCLUSIONS: IL-33 appears as a factor of aggravation of the disease in the spleen tissue of mice infected with L. donovani.