ISG20L2: an RNA nuclease regulating T cell activation.

ISG20L2, a 3' to 5' exoribonuclease previously associated with ribosome biogenesis, is identified here in activated T cells as an enzyme with a preferential affinity for uridylated miRNA substrates. This enzyme is upregulated in T lymphocytes upon TCR and IFN type I stimulation and appears to be involved in regulating T cell function. ISG20L2 silencing leads to an increased basal expression of CD69 and induces greater IL2 secretion. However, ISG20L2 absence impairs CD25 upregulation, CD3 synaptic accumulation and MTOC translocation towards the antigen-presenting cell during immune synapsis. Remarkably, ISG20L2 controls the expression of immunoregulatory molecules, such as AHR, NKG2D, CTLA-4, CD137, TIM-3, PD-L1 or PD-1, which show increased levels in ISG20L2 knockout T cells. The dysregulation observed in these key molecules for T cell responses support a role for this exonuclease as a novel RNA-based regulator of T cell function.This study was supported by grant P2022/BMD7209- INTEGRAMUNE from the Comunidad de Madrid, a grant from “La Caixa” Banking Foundation (HR17-00016) to FS-M; the Spanish Ministerio de Ciencia e Innovación (PDC2021-121719-I00 and PID2020-120412RB-I00 to FS-M), grant from AECC, CIBER Cardiovascular (CB16/11/00272, Fondo de Investigación Sanitaria del Instituto de Salud Carlos III and co-funding by Fondo Europeo de Desarrollo Regional FEDER). The Centro Nacional de Investigaciones Cardiovasculares (CNIC) is supported by the Spanish Ministry of Economy and Competitiveness (MINECO) and the Pro-CNIC Foundation, and is a Severo Ochoa Center of Excellence (MINECO award SEV-2015- 0505). Vaňáčová’s laboratory is supported by the Czech Science Foundation (20-19617S and 23-07372S to S.V.) and the institutional support CEITEC 2020 (LQ1601). ARG and SGD are supported by a grant from the Spanish Ministry of Universities. Funding agencies do not have intervened in the design of the studies, with no copyright over the study.S

Immune synapse formation promotes lipid peroxidation and MHC-I upregulation in licensed dendritic cells for efficient priming of CD8+ T cells

This study was supported by the Spanish Ministry of Science and Innovation (grants PID2020-120412RB-I00, PDC2021-121797-I00, PGC2018- 097019-BI00, PID2021-122348NB-I00, PLEC2022-009235, PLEC2022- 009298, PID2021-125415OB-I00, and PID2019-105761RB-I00); Comunidad de Madrid (INTEGRAMUNE, P2022/BMD7209 and IMMUNO-VAR, P2022/BMD-7333); Ramón Areces Foundation “Ciencias de la Vida y la Salud” (XIX Concurso-2018); “la Caixa” Banking Foundation (grants HR17-00016, HR17-00247, and HR22-00253); ProteoRed from Instituto de Salud Carlos III (PT17/0019/0003- ISCIII-SGEFI / ERDF); CIBER Cardiovascular (CB16/11/00272, CB16/11/00277); Agencia Estatal de Investigación (AEI); Fondo de Investigació n Sanitaria del Instituto de Salud Carlos III; co-funding by Fondo Europeo de Desarrollo Regional (FEDER); and European Research Council Starting Grant SYNVIVO 853179. D.C.-F. is supported by an INPhINIT Retaining Fellowship from “la Caixa” Foundation (LCF/BQ/DR19/11740010). S.I. is supported by a RYC-2016- 19463 fellowship. E.H. is supported by an FPI fellowship (PRE2019- 087509). We thank Miguel Vicente-Manzanares for critically reading the manuscript. The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia e Innovación (MCIN) and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (grant CEX2020-001041-S funded by MICIN/AEI/10.13039/501100011033). The QIAGEN IPA software was used to create Figs. 3a and 5a.S

The leukocyte activation receptor CD69 controls T cell differentiation through its interaction with galectin-1

CD69 is involved in immune cell homeostasis, regulating the T cell-mediated immune response through the control of Th17 cell differentiation. However, natural ligands for CD69 have not yet been described. Using recombinant fusion proteins containing the extracellular domain of CD69, we have detected the presence of a ligand(s) for CD69 on human dendritic cells (DCs). Pulldown followed by mass spectrometry analyses of CD69-binding moieties on DCs identified galectin-1 as a CD69 counterreceptor. Surface plasmon resonance and anti-CD69 blocking analyses demonstrated a direct and specific interaction between CD69 and galectin-1 that was carbohydrate dependent. Functional assays with both human and mouse T cells demonstrated the role of CD69 in the negative effect of galectin-1 on Th17 differentiation. Our findings identify CD69 and galectin-1 to be a novel regulatory receptor-ligand pair that modulates Th17 effector cell differentiation and functionThis work was funded by grants SAF2011-25834 and ERC-2011AdG 294340-GENTRIS to F.S.-M., RECAVA RD06/0014 from the Fondo de Investigaciones Sanitarias to J.V. and F.S.-M., and INDISNET 01592006 from the Comunidad de Madrid to F.S.-M. and P.M. and by grants from the Ministerio de Economia y Competitividad (PI11/01562 to P.N.) and the Generalitat de Catalunya-AGAUR (2009SGR1409 to P.N.). The Ministry of Science and Innovation and the Pro-CNIC Foundation support CNI

Extracellular vesicles from Listeria monocytogenes-infected dendritic cells alert the innate immune response.

Communication through cell-cell contacts and extracellular vesicles (EVs) enables immune cells to coordinate their responses against diverse types of pathogens. The function exerted by EVs in this context depends on the proteins and nucleic acids loaded into EVs, which elicit specific responses involved in the resolution of infection. Several mechanisms control protein and nucleic acid loading into EVs; in this regard, acetylation has been described as a mechanism of cellular retention during protein sorting to exosomes. HDAC6 is a deacetylase involved in the control of cytoskeleton trafficking, organelle polarity and cell migration, defense against Listeria monocytogenes (Lm) infection and other immune related functions. Here, we show that the protein content of dendritic cells (DCs) and their secreted EVs (DEVs) vary during Lm infection, is enriched in proteins related to antiviral functions compared to non-infected cells and depends on HDAC6 expression. Analyses of the post-translational modifications revealed an alteration of the acetylation and ubiquitination profiles upon Lm infection both in DC lysates and DEVs. Functionally, EVs derived from infected DCs upregulate anti-pathogenic genes (e.g. inflammatory cytokines) in recipient immature DCs, which translated into protection from subsequent infection with vaccinia virus. Interestingly, absence of Listeriolysin O in Lm prevents DEVs from inducing this anti-viral state. In summary, these data underscore a new mechanism of communication between bacteria-infected DC during infection as they alert neighboring, uninfected DCs to promote antiviral responses.This study was supported by grant PDI-2020-120412RB-I00, PDC2021-121797-I00, BIO2015-67580-P and PGC2018-097019-BI00 from the Spanish Ministry of Economy and Competitiveness (MINECO), grant S2017/BMD-3671-INFLAMUNE-CM from the Comunidad de Madrid, a grant from the Ramón Areces Foundation “Ciencias de la Vida y la Salud” (XIX Concurso-2018), “la Caixa” Banking Foundation (grants HR17-00016 and HR17-00247), BIOIMID (PIE13/041) and PRB3 (IPT17/0019 - ISCIII-SGEFI/ ERDF, ProteoRed) from Instituto de Salud Carlos III, CIBER Cardiovascular (CB16/11/00272), and Fondo de Investigación Sanitaria del Instituto de Salud Carlos III and co-funding by Fondo Europeo de Desarrollo Regional FEDER). IF-D is supported by a Fellowship from the Spanish Ministry of Science, Innovation, and Universities (FPU15/02539). DC-F is supported by a Fellowship from “la Caixa” Foundation (LCF/BQ/DR19/11740010). The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia e Innovación (MCIN) and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (CEX2020- 001041-S). Funding agencies did not intervene in the design of the studies, with no copyright over the study.S

Natural killer (NK) cell-derived extracellular-vesicle shuttled microRNAs control T cell responses.

Natural killer (NK) cells recognize and kill target cells undergoing different types of stress. NK cells are also capable of modulating immune responses. In particular, they regulate T cell functions. Small RNA next-generation sequencing of resting and activated human NK cells and their secreted extracellular vesicles (EVs) led to the identification of a specific repertoire of NK-EV-associated microRNAs and their post-transcriptional modifications signature. Several microRNAs of NK-EVs, namely miR-10b-5p, miR-92a-3p, and miR-155-5p, specifically target molecules involved in Th1 responses. NK-EVs promote the downregulation of GATA3 mRNA in CD4+ T cells and subsequent TBX21 de-repression that leads to Th1 polarization and IFN-γ and IL-2 production. NK-EVs also have an effect on monocyte and moDCs (monocyte-derived dendritic cells) function, driving their activation and increased presentation and costimulatory functions. Nanoparticle-delivered NK-EV microRNAs partially recapitulate NK-EV effects in mice. Our results provide new insights on the immunomodulatory roles of NK-EVs that may help to improve their use as immunotherapeutic tools.This manuscript was funded by grants PDI-2020-120412RB-I00 and PDC2021- 121719-I00 (FS-M) and PID2020- 119352RB-I00 (AS) from the Spanish Ministry of Economy and Competitiveness; CAM (S2017/BMD3671-INFLAMUNE-CM) from the Comunidad de Madrid (FS-M). CIBERCV (CB16/11/00272) and BIOIMID PIE13/041 from the Instituto de Salud Carlos. The current research has received funding from 'la Caixa' Foundation under the project code HR17-00016. Grants from Ramón Areces Foundation 'Ciencias de la Vida y de la Salud' (XIX Concurso-2018) and from Ayuda Fundación BBVA y Equipo de Investigación Científica (BIOMEDICINA-2018) (to FSM). The CNIC is supported by the Ministerio de Ciencia, Innovacion y Universidades and the Pro-CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015–0505). IMDEA Nanociencia acknowledges support from the ‘Severo Ochoa’ Programme for Centres of Excellence in R&D (MINECO, CEX2020-001039-S). SGD is supported by a grant from the Spanish Ministry of Universities. Authors thank Dr Miguel Vicente-Manzanares for critical review and editing. We also thank Dr Francisco Urbano and Dr Covadonga Aguado for their support with EM (TEM facilities, Universidad Autónoma de Madrid).S

MICa/b-dependent activation of natural killer cells by CD64+ inflammatory type 2 dendritic cells contributes to autoimmunity.

Primary Sjögren's syndrome (pSS) is an inflammatory autoimmune disorder largely mediated by type I and II interferon (IFN). The potential contribution of innate immune cells, such as natural killer (NK) cells and dendritic cells (DC), to the pSS pathology remains understudied. Here, we identified an enriched CD16+ CD56hi NK cell subset associated with higher cytotoxic function, as well as elevated proportions of inflammatory CD64+ conventional dendritic cell (cDC2) subtype that expresses increased levels of MICa/b, the ligand for the activating receptor NKG2D, in pSS individuals. Circulating cDC2 from pSS patients efficiently induced activation of cytotoxic NK cells ex vivo and were found in proximity to CD56+ NK cells in salivary glands (SG) from pSS patients. Interestingly, transcriptional activation of IFN signatures associated with the RIG-I/DDX60 pathway, IFN I receptor, and its target genes regulate the expression of NKG2D ligands on cDC2 from pSS patients. Finally, increased proportions of CD64hi RAE-1+ cDC2 and NKG2D+ CD11b+ CD27+ NK cells were present in vivo in the SG after poly I:C injection. Our study provides novel insight into the contribution and interplay of NK and cDC2 in pSS pathology and identifies new potential therapy targets.S

DataSheet_1_Extracellular vesicles from Listeria monocytogenes-infected dendritic cells alert the innate immune response.pdf [Dataset]

Supplementary Figure 1. Isolated EVs present typical size and topology. Supplementary Figure 2. Protein profiling from total cell lysates and their derived EVs from WT and KO-HDAC6 BMDCs. Supplementary Figure 3. Enrichment in acetylated and ubiquitinated DC proteins upon Lm infection. Supplementary Figure 4. Ubiquitination in K-48 and K-63 state in T lymphoblast total cell lysates and their derived EVs. Supplementary Figure 5. Pore filtration methods restrain Lm and do not induce strong antipathogenic responses. Supplementary Figure 6. IFN-β is detected following Lm infection. Table S1. List of antibodies used for Western-blot and Flow Cytometry and the used dilution. Table S2. List of primers, with their corresponding sequence, used for qPCR. Table S3: Protein quantification in total cell lysates Table S4: IPA analysis of total cell lysates: canonical pathways and diseases and functions category Table S5: Protein quantification in EVs Table S6: IPA analysis of EVs: diseases and functions category Table S7: Ubiquitinated and acetylated peptides in total cell lysates and EVs Table S8: Enrichment analysis of ubiquitinated and acetylated proteinsPeer reviewe