Cd38 deficiency ameliorates chronic graft versus Host disease murine lupus via a b-cell dependent mechanism

Trabajo presentado en el II Congreso investigación PTS, celebrado en Granada (España) del 09 al 11 de febrero de 2022.Absence of mouse cell surface receptor CD38 in Cd38-/- mice suggests that this receptor acts as positive regulator of inflammatory and autoimmune responses. Here we report that in the setting of a chronic graft versus host disease (cGVHD) lupus model induced by the transfer of B6.C-H2bm12/KhEg (bm12) spleen cells into co-isogenic Cd38-/- B6 mice causes milder lupus-like autoimmunity with lower levels of anti-ssDNA autoantibodies than the transfer of bm12 spleen cells into WT B6 mice. I In addition, significantly lower percentages of Tfh cells, as well as GC B cells, plasma cells and T-bet+CD11chi B cells are observed in Cd38-/- mice than in WT mice, while the expansion of Treg cells, and Tfr cells is normal, suggesting that the ability of Cd38-/- B cells to respond to allogeneic help from bm12 CD4+ T cells is greatly diminished. The frequencies of T-bet+CD11chi B cells, which are considered the precursors of the autoantibody secreting cells, correlate with anti-ssDNA autoantibody serum levels, with IL-27, and sCD40L. Proteomics profiling of spleens from WT cGVHD mice reflects a STAT1-driven type I IFN-signature, which is absent in Cd38-/- cGVHD mice. Kidney, spleen and liver inflammation was mild and resolved faster in Cd38-/- cGVHD mice than in WT cGVHD mice. We conclude that in B cells CD38 functions as a modulator receptor that controls autoimmune responses

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions

LmABCB3, an atypical mitochondrial ABC transporter essential for Leishmania major virulence, acts in heme and cytosolic iron/sulfur clusters biogenesis

Abstract Background Mitochondria play essential biological functions including the synthesis and trafficking of porphyrins and iron/sulfur clusters (ISC), processes that in mammals involve the mitochondrial ATP-Binding Cassette (ABC) transporters ABCB6 and ABCB7, respectively. The mitochondrion of pathogenic protozoan parasites such as Leishmania is a promising goal for new therapeutic approaches. Leishmania infects human macrophages producing the neglected tropical disease known as leishmaniasis. Like most trypanosomatid parasites, Leishmania is auxotrophous for heme and must acquire porphyrins from the host. Methods LmABCB3, a new Leishmania major protein with significant sequence similarity to human ABCB6/ABCB7, was identified and characterized using bioinformatic tools. Fluorescent microscopy was used to determine its cellular localization, and its level of expression was modulated by molecular genetic techniques. Intracellular in vitro assays were used to demonstrate its role in amastigotes replication, and an in vivo mouse model was used to analyze its role in virulence. Functional characterization of LmABCB3 was carried out in Leishmania promastigotes and Saccharomyces cerevisiae. Structural analysis of LmABCB3 was performed using molecular modeling software. Results LmABCB3 is an atypical ABC half-transporter that has a unique N-terminal extension not found in any other known ABC protein. This extension is required to target LmABCB3 to the mitochondrion and includes a potential metal-binding domain. We have shown that LmABCB3 interacts with porphyrins and is required for the mitochondrial synthesis of heme from a host precursor. We also present data supporting a role for LmABCB3 in the biogenesis of cytosolic ISC, essential cofactors for cell viability in all three kingdoms of life. LmABCB3 fully complemented the severe growth defect shown in yeast lacking ATM1, an orthologue of human ABCB7 involved in exporting from the mitochondria a gluthatione-containing compound required for the generation of cytosolic ISC. Indeed, docking analyzes performed with a LmABCB3 structural model using trypanothione, the main thiol in this parasite, as a ligand showed how both, LmABCB3 and yeast ATM1, contain a similar thiol-binding pocket. Additionally, we show solid evidence suggesting that LmABCB3 is an essential gene as dominant negative inhibition of LmABCB3 is lethal for the parasite. Moreover, the abrogation of only one allele of the gene did not impede promastigote growth in axenic culture but prevented the replication of intracellular amastigotes and the virulence of the parasites in a mouse model of cutaneous leishmaniasis. Conclusions Altogether our results present the previously undescribed LmABCB3 as an unusual mitochondrial ABC transporter essential for Leishmania survival through its role in the generation of heme and cytosolic ISC. Hence, LmABCB3 could represent a novel target to combat leishmaniasis. Keywords Heme trafficking and metabolism Iron/sulfur clusters Trypanosomatid parasites Mitochondrial ABC transporter LeishmaniaThis work was supported by grants from the Spanish Ministerio de Economía y Competitividad SAF2011-28215 (JMPV) and Junta de Andalucia BIO1786 (JMPV) and by FEDER funds from the EU to JMPV. MMG was recipient of a FPI fellowship from the Spanish Ministerio de Economía y Competitividad; MCD was recipient of a FPU fellowship from the Spanish Ministerio de Educación, Cultura y Deporte; SMC was recipient of a JAE-DOC from the Spanish CSIC (Ministerio de Economía y Competitividad), cofounded by the Fondo Social Europeo.Peer reviewe

Trypanosomatid parasites rescue heme from endocytosed hemoglobin through lysosomal HRG transporters

Pathogenic trypanosomatid parasites are auxotrophic for heme and they must scavenge it from their human host. Trypanosoma brucei (responsible for sleeping sickness) and Leishmania (leishmaniasis) can fulfill heme requirement by receptor-mediated endocytosis of host hemoglobin. However, the mechanism used to transfer hemoglobin-derived heme from the lysosome to the cytosol remains unknown. Here we provide strong evidence that HRG transporters mediate this essential step. In bloodstream T. brucei, TbHRG localizes to the endolysosomal compartment where endocytosed hemoglobin is known to be trafficked. TbHRG overexpression increases cytosolic heme levels whereas its down-regulation is lethal for the parasites unless they express the Leishmania orthologue LmHR1. LmHR1, known to be an essential plasma membrane protein responsible for the uptake of free heme in Leishmania, is also present in its acidic compartments which colocalize with endocytosed hemoglobin. Moreover, LmHR1 levels modulated by its overexpression or the abrogation of an LmHR1 allele correlate with the mitochondrial bioavailability of heme from lysosomal hemoglobin. In addition, using heme auxotrophic yeasts we show that TbHRG and LmHR1 transport hemoglobin-derived heme from the digestive vacuole to the cytosol. Collectively, these results show that trypanosomatid parasites rescue heme from endocytosed hemoglobin through endolysosomal HRG transporters, which could constitute novel drug targets.We thank Ivan Hapala (IABG-SAS, Slovakia), Stephen M.Beverley (Washington University School of Medicine, USA)and Olivier Cagnac (EEZ-CSIC, Spain) for kindly providing,respectively, thehem1Dyeast strain, theLeishmaniaandthe yeast vectors used throughout this research work. Wethank Ignacio Perez-Victoria for the preparation of ApoHb.We are grateful to Jean Mathieu Bart (IPBLN-CSIC, Spain)for helpful discussions. This work was supported by Span-ish grants BIO1786 (JMPV) from the Junta de Andalucıa and SAF2011-28215 (JMPV) and BFU2014-55193-P (AE)from the Ministerio de Economıa y Competitividad and by FEDER funds from the EU to JMPV and AE. MCD was astudent of the PhD program “Biochemistry and MolecularBiology” of the University of Granada (Spain). MCD was recipient of a FPU fellowship from the Spanish Ministerio de Educacion, Cultura y Deporte; SMC was recipient of a JAE-DOC from the Spanish CSIC (Ministerio de Economıa y Competitividad), cofounded by the Fondo Social Europeo,LMOZ was recipient of a Colciencias fellowship from the Colombian Ministerio de Ciencia, Tecnologıa e Innovacion;MMG was recipient of a FPI fellowship from the Spanish Ministerio de Economıa y Competitividad. The authorsdeclare that they have no conflict of interestPeer reviewe

Neutrophil and Monocyte Function in Patients with Chronic Hepatitis C Undergoing Antiviral Therapy with Regimens Containing Protease Inhibitors with and without Interferon

Real-life data showed an increased incidence of bacterial infections in patients with advanced liver disease receiving a protease inhibitor (PI)-containing antiviral regimen against hepatitis C (HCV). However, the causes of this event are unknown. We hypothesized that PIs might impair innate immune responses through the inhibition of proteases participating in the anti-bacterial functions of neutrophils and monocytes. The aims of the study were to assess phagocytic and oxidative burst capacity in neutrophils and monocytes obtained from patients receiving a PI containing-antiviral regimen, and to determine cytokine secretion after neutrophil stimulation with flagellin. Forty patients with chronic HCV (80% with cirrhosis) were enrolled in the study, 28 received triple therapy (Group A) with pegylated-interferon and ribavirin for 4 weeks followed by the addition of a PI (telaprevir, boceprevir or simeprevir), and 12 patients received an interferon-free regimen (Group B) with simeprevir and sofosbuvir. Phagocytosis and oxidative burst capacity were analyzed by flow cytometry at baseline, week 4, and week 8 of therapy. In neutrophils from Group A patients, oxidative burst rate and oxidative enzymatic activity per cell significantly decreased throughout the study period (p = 0.014 and p = 0.010, respectively). Pairwise comparisons showed a decrease between baseline and week 4 and 8 of therapy. No differences were observed after the introduction of the PI. The oxidative enzymatic activity per cell in monocytes significantly decrease during the study period (p = 0.042) due to a decrease from baseline to week 8 of therapy (p = 0.037) in patients from Group A. None of these findings were observed in Group B patients. Cytokine secretion did not significantly change during the study in both groups. In conclusion, our data suggest that the use interferon (rather than the PI) has a deleterious effect on neutrophil and monocyte phagocytic and oxidative burst capacity in this cohort of patients with HCV-related advanced liver fibrosis

A deletion at Adamts9-magi1 Locus is associated with psoriatic arthritis risk

Objective: Copy number variants (CNVs) have been associated with the risk to develop multiple autoimmune diseases. Our objective was to identify CNVs associated with the risk to develop psoriatic arthritis (PsA) using a genome-wide analysis approach. Methods: A total of 835 patients with PsA and 1498 healthy controls were genotyped for CNVs using the Illumina HumanHap610 BeadChip genotyping platform. Genomic CNVs were characterised using CNstream analysis software and analysed for association using the χ2 test. The most significant genomic CNV associations with PsA risk were independently tested in a validation sample of 1133 patients with PsA and 1831 healthy controls. In order to test for the specificity of the variants with PsA aetiology, we also analysed the association to a cohort of 822 patients with purely cutaneous psoriasis (PsC). Results: A total of 165 common CNVs were identified in the genome-wide analysis. We found a highly significant association of an intergenic deletion between ADAMTS9 and MAGI1 genes on chromosome 3p14.1 (p=0.00014). Using the independent patient and control cohort, we validated the association between ADAMTS9-MAGI1 deletion and PsA risk (p=0.032). Using next-generation sequencing, we characterised the 26 kb associated deletion. Finally, analysing the PsC cohort we found a lower frequency of the deletion compared with the PsA cohort (p=0.0088) and a similar frequency to that of healthy controls (p>0.3). Conclusions: The present genome-wide scan for CNVs associated with PsA risk has identified a new deletion associated with disease risk and which is also differential from PsC risk