An emerging role for NAADP-mediated Ca2+ signaling in the pancreatic beta-cell

Several recent reports, including one in this journal, have reignited the debate about whether the calcium-mobilizing messenger, nicotinic adenine nucleotide diphosphate (NAADP) plays a central role in the regulation of calcium signalling in pancreatic β-cell. These studies have highlighted a role for NAADP-induced Ca(2+) mobilization not only in mediating the effects of the incretin, GLP-1 and the autocrine proliferative effects of insulin, but also possibly a fundamental role in glucose-mediated insulin secretion in the pancreatic β-cell

The Serums Tool-Chain:Ensuring Security and Privacy of Medical Data in Smart Patient-Centric Healthcare Systems

Digital technology is permeating all aspects of human society and life. This leads to humans becoming highly dependent on digital devices, including upon digital: assistance, intelligence, and decisions. A major concern of this digital dependence is the lack of human oversight or intervention in many of the ways humans use this technology. This dependence and reliance on digital technology raises concerns in how humans trust such systems, and how to ensure digital technology behaves appropriately. This works considers recent developments and projects that combine digital technology and artificial intelligence with human society. The focus is on critical scenarios where failure of digital technology can lead to significant harm or even death. We explore how to build trust for users of digital technology in such scenarios and considering many different challenges for digital technology. The approaches applied and proposed here address user trust along many dimensions and aim to build collaborative and empowering use of digital technologies in critical aspects of human society

Uncovering a neurological protein signature for severe COVID-19

Coronavirus disease of 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has sparked a global pandemic with severe complications and high morbidity rate. Neurological symptoms in COVID-19 patients, and neurological sequelae post COVID-19 recovery have been extensively reported. Yet, neurological molecular signature and signaling pathways that are affected in the central nervous system (CNS) of COVID-19 severe patients remain still unknown and need to be identified. Plasma samples from 49 severe COVID-19 patients, 50 mild COVID-19 patients, and 40 healthy controls were subjected to Olink proteomics analysis of 184 CNS-enriched proteins. By using a multi-approach bioinformatics analysis, we identified a 34-neurological protein signature for COVID-19 severity and unveiled dysregulated neurological pathways in severe cases. Here, we identified a new neurological protein signature for severe COVID-19 that was validated in different independent cohorts using blood and postmortem brain samples and shown to correlate with neurological diseases and pharmacological drugs. This protein signature could potentially aid the development of prognostic and diagnostic tools for neurological complications in post-COVID-19 convalescent patients with long term neurological sequelae

A novel assay of antimycobacterial activity and phagocytosis by human neutrophils

SummaryDespite abundant evidence that neutrophils arrive early at sites of mycobacterial disease and phagocytose organisms, techniques to assay phagocytosis or killing of mycobacteria by these cells are lacking. Existing assays for measuring the antimycobacterial activity of human leukocytes require cell lysis which introduces new bioactive substances and may be incomplete. They are also time-consuming and carry multiple risks of inaccuracy due to serial dilution and organism clumping. Flow cytometric techniques for measuring phagocytosis of mycobacteria by human cells have failed to adequately address the effects of organism clumping, quenching agents and culture conditions on readouts.Here we present a novel in-tube bioluminescence-based assay of antimycobacterial activity by human neutrophils. The assay yields intuitive results, with improving restriction of mycobacterial bioluminescence as the ratio of cells to organisms increases. We show that lysis of human cells is not required to measure luminescence accurately.We also present a phagocytosis assay in which we have minimised the impact of mycobacterial clumping, investigated the effect of various opsonisation techniques and established the correct usage of trypan blue to identify surface-bound organisms without counting dead cells. The same multiplicity of infection and serum conditions are optimal to demonstrate both internalisation and restriction of mycobacterial growth

NAD+ protects against EAE by regulating CD4+ T-cell differentiation

CD4+ T cells are involved in the development of autoimmunity, including multiple sclerosis (MS). Here we show that nicotinamide adenine dinucleotide (NAD+) blocks experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, by inducing immune homeostasis through CD4+IFNγ+IL-10+ T cells and reverses disease progression by restoring tissue integrity via remyelination and neuroregeneration. We show that NAD+ regulates CD4+ T-cell differentiation through tryptophan hydroxylase-1 (Tph1), independently of well-established transcription factors. In the presence of NAD+, the frequency of T-bet−/− CD4+IFNγ+ T cells was twofold higher than wild-type CD4+ T cells cultured in conventional T helper 1 polarizing conditions. Our findings unravel a new pathway orchestrating CD4+ T-cell differentiation and demonstrate that NAD+ may serve as a powerful therapeutic agent for the treatment of autoimmune and other diseases

Innate Immune Response of Human Alveolar Macrophages during Influenza A Infection

Alveolar macrophages (AM) are one of the key cell types for initiating inflammatory and immune responses to influenza virus in the lung. However, the genome-wide changes in response to influenza infection in AM have not been defined. We performed gene profiling of human AM in response to H1N1 influenza A virus PR/8 using Affymetrix HG-U133 Plus 2.0 chips and verified the changes at both mRNA and protein levels by real-time RT-PCR and ELISA. We confirmed the response with a contemporary H3N2 influenza virus A/New York/238/2005 (NY/238). To understand the local cellular response, we also evaluated the impact of paracrine factors on virus-induced chemokine and cytokine secretion. In addition, we investigated the changes in the expression of macrophage receptors and uptake of pathogens after PR/8 infection. Although macrophages fail to release a large amount of infectious virus, we observed a robust induction of type I and type III interferons and several cytokines and chemokines following influenza infection. CXCL9, 10, and 11 were the most highly induced chemokines by influenza infection. UV-inactivation abolished virus-induced cytokine and chemokine response, with the exception of CXCL10. The contemporary influenza virus NY/238 infection of AM induced a similar response as PR/8. Inhibition of TNF and/or IL-1β activity significantly decreased the secretion of the proinflammatory chemokines CCL5 and CXCL8 by over 50%. PR/8 infection also significantly decreased mRNA levels of macrophage receptors including C-type lectin domain family 7 member A (CLEC7A), macrophage scavenger receptor 1 (MSR1), and CD36, and reduced uptake of zymosan. In conclusion, influenza infection induced an extensive proinflammatory response in human AM. Targeting local components of innate immune response might provide a strategy for controlling influenza A infection-induced proinflammatory response in vivo

MARCO, TLR2, and CD14 Are Required for Macrophage Cytokine Responses to Mycobacterial Trehalose Dimycolate and Mycobacterium tuberculosis

Virtually all of the elements of Mycobacterium tuberculosis (Mtb) pathogenesis, including pro-inflammatory cytokine production, granuloma formation, cachexia, and mortality, can be induced by its predominant cell wall glycolipid, trehalose 6,6′-dimycolate (TDM/cord factor). TDM mediates these potent inflammatory responses via interactions with macrophages both in vitro and in vivo in a myeloid differentiation factor 88 (MyD88)-dependent manner via phosphorylation of the mitogen activated protein kinases (MAPKs), implying involvement of toll-like receptors (TLRs). However, specific TLRs or binding receptors for TDM have yet to be identified. Herein, we demonstrate that the macrophage receptor with collagenous structure (MARCO), a class A scavenger receptor, is utilized preferentially to “tether” TDM to the macrophage and to activate the TLR2 signaling pathway. TDM-induced signaling, as measured by a nuclear factor-kappa B (NF-κB)-luciferase reporter assay, required MARCO in addition to TLR2 and CD14. MARCO was used preferentially over the highly homologous scavenger receptor class A (SRA), which required TLR2 and TLR4, as well as their respective accessory molecules, in order for a slight increase in NF-κB signaling to occur. Consistent with these observations, macrophages from MARCO−/− or MARCO−/−SRA−/− mice are defective in activation of extracellular signal-related kinase 1/2 (ERK1/2) and subsequent pro-inflammatory cytokine production in response to TDM. These results show that MARCO-expressing macrophages secrete pro-inflammatory cytokines in response to TDM by cooperation between MARCO and TLR2/CD14, whereas other macrophage subtypes (e.g. bone marrow–derived) may rely somewhat less effectively on SRA, TLR2/CD14, and TLR4/MD2. Macrophages from MARCO−/− mice also produce markedly lower levels of pro-inflammatory cytokines in response to infection with virulent Mtb. These observations identify the scavenger receptors as essential binding receptors for TDM, explain the differential response to TDM of various macrophage populations, which differ in their expression of the scavenger receptors, and identify MARCO as a novel component required for TLR signaling

Genetic Variants in MARCO Are Associated with the Susceptibility to Pulmonary Tuberculosis in Chinese Han Population

BACKGROUND: Susceptibility to tuberculosis is not only determined by Mycobacterium tuberculosis infection, but also by the genetic component of the host. Macrophage receptor with a collagenous structure (MARCO) is essential components required for toll like receptor-signaling in macrophage response to Mycobacterium tuberculosis, which may contribute to tuberculosis risk. PRINCIPAL FINDINGS: To specifically investigated whether single nucleotide polymorphisms (SNPs) in MARCO gene are associated with pulmonary tuberculosis in Chinese Han population. By selecting tagging SNPs in MARCO gene, 17 tag SNPs were identified and genotyped in 923 pulmonary tuberculosis patients and 1033 healthy control subjects using a hospital based case-control association study. Single-point and haplotype analysis revealed an association in intron and exon region of MARCO gene. One SNP (rs17009726) was associated with susceptibility to pulmonary tuberculosis, where the carriers of the G allele had a 1.65 fold (95% CI = 1.32-2.05, p(corrected) = 9.27E-5) increased risk of pulmonary tuberculosis. Haplotype analysis revealed that haplotype GC containing G allele of 17009726 and haplotype TGCC (rs17795618T/A, rs1371562G/T, rs6761637T/C, rs2011839C/T) were also associated with susceptibility to pulmonary tuberculosis (p(corrected) = 0.0001 and 0.029, respectively). CONCLUSIONS: Our study suggested that genetic variants in MARCO gene were associated with pulmonary tuberculosis susceptibility in Chinese Han population, and the findings emphasize the importance of MARCO mediated immune responses in the pathogenesis of tuberculosis

Scavenger receptors and β-glucan receptors participate in the recognition of yeasts by murine macrophages

Objectives: Numerous receptors have been implicated in recognition of pathogenic fungi by macrophages, including the $\beta$-glucan receptor dectin-1. The role of scavenger receptors (SRs) in anti-fungal immunity is not well characterized. Methods: We studied uptake of unopsonized Saccharomycetes cerevisiae (zymosan) and live Candida albicans yeasts as well as zymosan-stimulated $H_2O_2$ production in J774 macrophage-like cells and peritoneal exudate macrophages (PEMs). The role of different receptors was assessed with the use of competitive ligands, transfected cells and receptor-deficient macrophages. Results: The uptake of zymosan by untreated J774 cells was mediated approximately half by SRs and half by a $\beta$-glucan receptor which was distinct from dectin-1 and not linked to stimulation of $H_2O_2$ production. Ligands of $\beta$-glucan receptors and of SRs also inhibited uptake of C. albicans by macrophages (J774 cells and PEMs). In macrophages pretreated with a CpG motif-containing oligodeoxynucleotide (CpG-ODN) the relative contribution of SRs to yeast uptake increased and that of $\beta$-glucan receptors decreased. Whereas the class A SR MARCO participated in the uptake of both zymosan and C. albicans by CpG-ODN-pretreated, but not untreated macrophages, the related receptor SR-A/CD204 was involved in the uptake of zymosan, but not of C. albicans. The reduction of zymosan-stimulated $H_2O_2$ production observed in DS-pretreated J774 cells and in class A SRs-deficient PEMs suggest that class A SRs mediate part of this process. Conclusions: Our results revealed that SRs belong to a redundant system of receptors for yeasts. Binding of yeasts to different receptors in resting versus CpG-ODN-pre-exposed macrophages may differentially affect polarization of adaptive immune responses

Haptoglobin and Sickle Cell Polymorphisms and Risk of Active Trachoma in Gambian Children

BACKGROUND: Susceptibility and resistance to trachoma, the leading infectious cause of blindness, have been associated with a range of host genetic factors. In vitro studies of the causative organism, Chlamydia trachomatis, demonstrate that iron availability regulates its growth, suggesting that host genes involved in regulating iron status and/or availability may modulate the risk of trachoma. The objective was to investigate whether haptoglobin (Hp) haplotypes constructed from the functional polymorphism (Hp1/Hp2) plus the functional promoter SNPs -61A-C (rs5471) and -101C-G (rs5470), or sickle cell trait (HbAS, rs334) were associated with risk of active trachoma when stratified by age and sex, in rural Gambian children. METHODOLOGY AND PRINCIPAL FINDINGS: In two cross sectional surveys of children aged 6-78 months (n = 836), the prevalence of the clinical signs of active trachoma was 21.4%. Within boys, haplotype E (-101G, -61A, Hp1), containing the variant allele of the -101C-G promoter SNP, was associated with a two-fold increased risk of active trachoma (OR = 2.0 [1.17-3.44]). Within girls, an opposite association was non-significant (OR = 0.58 [0.32-1.04]; P = 0.07) and the interaction by sex was statistically significant (P = 0.001). There was no association between trachoma and HbAS. CONCLUSIONS: These data indicate that genetic variation in Hp may affect susceptibility to active trachoma differentially by sex in The Gambia