Tumor-derived extracellular vesicles (EVs) have been associated with immune evasion and tumor progression. We show that the RNA-sensing receptor RIG-I within tumor cells governs biogenesis and ...immunomodulatory function of EVs. Cancer-intrinsic RIG-I activation releases EVs, which mediate dendritic cell maturation and T cell antitumor immunity, synergizing with immune checkpoint blockade. Intact RIG-I, autocrine interferon signaling, and the GTPase Rab27a in tumor cells are required for biogenesis of immunostimulatory EVs. Active intrinsic RIG-I signaling governs composition of the tumor EV RNA cargo including small non-coding stimulatory RNAs. High transcriptional activity of EV pathway genes and RIG-I in melanoma samples associate with prolonged patient survival and beneficial response to immunotherapy. EVs generated from human melanoma after RIG-I stimulation induce potent antigen-specific T cell responses. We thus define a molecular pathway that can be targeted in tumors to favorably alter EV immunomodulatory function. We propose “reprogramming” of tumor EVs as a personalized strategy for T cell-mediated cancer immunotherapy.
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RIG-I activity regulates biogenesis and function of tumor cell-derived EVs
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Cancer-intrinsic RIG-I signaling governs the composition of the EV RNA cargo
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Immunostimulatory EVs trigger T cell-based antitumor immunity in mice and humans
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EV and RIG-I gene signatures in melanomas correlate with response to immunotherapy
Extracellular vesicles harbor extraordinary potential for cancer therapy, but one limitation is an inadequate understanding of signaling pathways that regulate their biogenesis and function. Heidegger et al. define a tumor-intrinsic molecular pathway that can be targeted to modulate tumor EV cargo constituents and thus their immunomodulatory potential on T cell immunity.
Background. Human ficolin 2 (encoded by FCN2) and mannose-binding lectin (encoded by MBL2) bind to specific pathogen-associated molecular patterns, activate the complement lectin cascade in a similar ...manner, and are associated with several infectious diseases. Our recently published study established certain FCN2 promoter variants and ficolin-2 serum levels as protective factors against schistosomiasis. Methods. We used the Nigerian cohort from our recently published study, which included 163 Schistosoma haematobium—infected individuals and 183 matched healthy subjects, and investigated whether MBL deficiency and MBL2 polymorphisms are associated with schistosomiasis. Results. MBL serum levels were significantly higher in controls and were associated with protection (P < .0001). The -550H minor allele was significantly associated with protection (P = .03), and the heterozygous genotypes -550HL were observed to confer protection (P = .03). The MBL2*HYPA haplotype was significantly associated with protection (P = .03), with significantly higher serum MBL levels in controls (P = .00073). The heterozygous 6-bp deletion in the promoter was observed to be a susceptibility factor in schistosomiasis (P = .03). Conclusions. In agreement with findings from our recently published study, the findings reported here support the observation that MBL is also associated with protection in schistosomiasis.
Deficiency in X-linked inhibitor of apoptosis protein (XIAP) is the cause for X-linked lymphoproliferative syndrome 2 (XLP2). About one-third of these patients suffer from severe and ...therapy-refractory inflammatory bowel disease (IBD), but the exact cause of this pathogenesis remains undefined. Here, we used XIAP-deficient mice to characterize the mechanisms underlying intestinal inflammation. In
mice, we observed spontaneous terminal ileitis and microbial dysbiosis characterized by a reduction of
species. We showed that in inflamed mice, both TNF receptor 1 and 2 (TNFR1/2) cooperated in promoting ileitis by targeting TLR5-expressing Paneth cells (PCs) or dendritic cells (DCs). Using intestinal organoids and in vivo modeling, we demonstrated that TLR5 signaling triggered TNF production, which induced PC dysfunction mediated by TNFR1. TNFR2 acted upon lamina propria immune cells. scRNA-seq identified a DC population expressing TLR5, in which
expression was also elevated. Thus, the combined activity of TLR5 and TNFR2 signaling may be responsible for DC loss in lamina propria of
mice. Consequently, both
and
mice were rescued from dysbiosis and intestinal inflammation. Furthermore, RNA-seq of ileal crypts revealed that in inflamed
mice, TLR5 signaling was abrogated, linking aberrant TNF responses with the development of a dysbiosis. Evidence for TNFR2 signaling driving intestinal inflammation was detected in XLP2 patient samples. Together, these data point toward a key role of XIAP in mediating resilience of TLR5-expressing PCs and intestinal DCs, allowing them to maintain tissue integrity and microbiota homeostasis.
In contrast to mono- or biallelic loss of tumor-suppressor function, effects of discrete gene dysregulations, as caused by non-coding (epi)genome alterations, are poorly understood. Here, by ...perturbing the regulatory genome in mice, we uncover pervasive roles of subtle gene expression variation in cancer evolution. Genome-wide screens characterizing 1,450 tumors revealed that such quasi-insufficiency is extensive across entities and displays diverse context dependencies, such as distinct cell-of-origin associations in T-ALL subtypes. We compile catalogs of non-coding regions linked to quasi-insufficiency, show their enrichment with human cancer risk variants, and provide functional insights by engineering regulatory alterations in mice. As such, kilo-/megabase deletions in a Bcl11b-linked non-coding region triggered aggressive malignancies, with allele-specific tumor spectra reflecting gradual gene dysregulations through modular and cell-type-specific enhancer activities. Our study constitutes a first survey toward a systems-level understanding of quasi-insufficiency in cancer and gives multifaceted insights into tumor evolution and the tissue-specific effects of non-coding mutations.
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•Methods mapping cellular, molecular, and temporal parameters in cancer evolution•Non-coding genome perturbation reveals extensive quasi-insufficiency in cancer•Quasi-insufficiency is context dependent: T-ALL subtype-specific extents/patterns•Gene desert deletion series causes cancer in mice with allele-specific tumor spectra
Fischer et al. report screening methods interrogating the non-coding genome in mice, which uncovered widespread roles of subtle gene dysregulations in cancer evolution. They show that such quasi-insufficiency is extensive across entities. The discoveries give insights into the impairment of tumor suppression by human cancer risk variants and the tissue-specific effects of non-coding mutations.
Renal ischemia-reperfusion injury (IRI) is associated with reduced allograft survival, and each additional hour of cold ischemia time increases the risk of graft failure and mortality following renal ...transplantation. Receptor-interacting protein kinase 3 (RIPK3) is a key effector of necroptosis, a regulated form of cell death. Here, we evaluate the first-in-human RIPK3 expression dataset following IRI in kidney transplantation. The primary analysis included 374 baseline biopsy samples obtained from renal allografts 10 minutes after onset of reperfusion. RIPK3 was primarily detected in proximal tubular cells and distal tubular cells, both of which are affected by IRI. Time-to-event analysis revealed that high RIPK3 expression is associated with a significantly higher risk of one-year transplant failure and prognostic for one-year (death-censored) transplant failure independent of donor and recipient associated risk factors in multivariable analyses. The RIPK3 score also correlated with deceased donation, cold ischemia time and the extent of tubular injury.
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•First-in-human study comparing RIPK3 expression in renal biopsies with clinical outcome•RIPK3 expression correlates with cold ischemia time•RIPK3 expression is associated with a higher risk of 1-year transplant failure•RIPK3 expression predicts 1-year graft failure independent of recipient risk factors
Nephrology; Molecular biology
Background Current artesunate (ARS) regimens for severe malaria are complex. Once daily intramuscular (i.m.) injection for 3 d would be simpler and more appropriate for remote health facilities than ...the current WHO-recommended regimen of five intravenous (i.v.) or i.m. injections over 4 d. We compared both a three-dose i.m. and a three-dose i.v. parenteral ARS regimen with the standard five-dose regimen using a non-inferiority design (with non-inferiority margins of 10%). Methods and Findings This randomized controlled trial included children (0.5-10 y) with severe malaria at seven sites in five African countries to assess whether the efficacy of simplified three-dose regimens is non-inferior to a five-dose regimen. We randomly allocated 1,047 children to receive a total dose of 12 mg/kg ARS as either a control regimen of five i.m. injections of 2.4 mg/kg (at 0, 12, 24, 48, and 72 h) (n = 348) or three injections of 4 mg/kg (at 0, 24, and 48 h) either i.m. (n = 348) or i.v. (n = 351), both of which were the intervention arms. The primary endpoint was the proportion of children with ≥99% reduction in parasitemia at 24 h from admission values, measured by microscopists who were blinded to the group allocations. Primary analysis was performed on the per-protocol population, which was 96% of the intention-to-treat population. Secondary analyses included an analysis of host and parasite genotypes as risks for prolongation of parasite clearance kinetics, measured every 6 h, and a Kaplan-Meier analysis to compare parasite clearance kinetics between treatment groups. A post hoc analysis was performed for delayed anemia, defined as hemoglobin ≤ 7g/dl 7 d or more after admission. The per-protocol population was 1,002 children (five-dose i.m.: n = 331; three-dose i.m.: n = 338; three-dose i.v.: n = 333); 139 participants were lost to follow-up. In the three-dose i.m. arm, 265/338 (78%) children had a ≥99% reduction in parasitemia at 24 h compared to 263/331 (79%) receiving the five-dose i.m. regimen, showing non-inferiority of the simplified three-dose regimen to the conventional five-dose regimen (95% CI -7, 5; p = 0.02). In the three-dose i.v. arm, 246/333 (74%) children had ≥99% reduction in parasitemia at 24 h; hence, non-inferiority of this regimen to the five-dose control regimen was not shown (95% CI -12, 1; p = 0.24). Delayed parasite clearance was associated with the N86YPfmdr1 genotype. In a post hoc analysis, 192/885 (22%) children developed delayed anemia, an adverse event associated with increased leukocyte counts. There was no observed difference in delayed anemia between treatment arms. A potential limitation of the study is its open-label design, although the primary outcome measures were assessed in a blinded manner. Conclusions A simplified three-dose i.m. regimen for severe malaria in African children is non-inferior to the more complex WHO-recommended regimen. Parenteral ARS is associated with a risk of delayed anemia in African children. Trial registration Pan African Clinical Trials Registry PACTR201102000277177
Background Helminth infections are a major public health problem, especially in the tropics. Infected individuals have an altered immune response with evidence that antibody response to vaccination ...is impaired. Hence, treatment of helminth infections before vaccination may be a simple intervention to improve vaccine immunogenicity. In the present study we investigated whether a single-dose antihelminthic treatment influences antibody responses to a seasonal influenza vaccine in primary school children living in Gabon, Central Africa. Methods In this placebo-controlled double-blind trial conducted in Gabon the effect of a single-dose antihelminthic treatment with 400 mg albendazole versus a placebo one month prior to immunization with a seasonal influenza vaccine was investigated. Antiviral antibody titers against all three vaccine strains were assessed by haemagglutination inhibition (HI) test at baseline (Day 0; vaccination) and four weeks (Day 28) as well as 12 weeks (Day 84) following vaccination. Vaccine-specific memory B-cell response was measured at Day 0 and Day 84 by vaccine-specific Enzyme-linked Immunospot (ELISpot) assay. The trial is registered with the Pan African Clinical Trials Registry (PACTR) (PACTR201303000434188). Results 98 school children aged 6-10 years were randomly allocated to receive either antihelminthic treatment or placebo and were vaccinated one month after the treatment. The prevalence of helminths at baseline was 21%. Vaccine-specific HI titers against at least one of the three vaccine strains increased at Day 28 and Day 84 in all participants. HI titers against both influenza A strains as well as memory B-cell response were modestly higher in the antihelminthic treated group compared to the placebo group but the difference was not statistically significant. Total but not specific IgA was elevated in the antihelminthic treated group compared to the control group at Day 28. Conclusion In our setting antihelminthic treatment had no significant effect on influenza vaccine immunogenicity. A trend towards better antiviral and vaccine immunogenicity in the antihelminthic treated group encourages studies to be conducted with alternative treatment schedules or in populations with a higher helminth burden.
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