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Found 37003 matches. Displaying 161-170
Naik S, Fuchs E
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Inflammatory memory and tissue adaptation in sickness and in health

NATURE 2022 JUL 14; 607(7918):249-+
Our body has a remarkable ability to remember its past encounters with allergens, pathogens, wounds and irritants, and to react more quickly to the next experience. This accentuated sensitivity also helps us to cope with new threats. Despite maintaining a state of readiness and broadened resistance to subsequent pathogens, memories can also be maladaptive, leading to chronic inflammatory disorders and cancers. With the ever-increasing emergence of new pathogens, allergens and pollutants in our world, the urgency to unravel the molecular underpinnings of these phenomena has risen to new heights. Here we reflect on how the field of inflammatory memory has evolved, since 2007, when researchers realized that non-specific memory is contained in the nucleus and propagated at the epigenetic level. We review the flurry of recent discoveries revealing that memory is not just a privilege of the immune system but also extends to epithelia of the skin, lung, intestine and pancreas, and to neurons. Although still unfolding, epigenetic memories of inflammation have now been linked to possible brain disorders such as Alzheimer disease, and to an elevated risk of cancer. In this Review, we consider the consequences-good and bad-of these epigenetic memories and their implications for human health and disease.
Rosain J, Bernasconi A, Prieto E, Caputi L, Le Voyer T, Buda G, Marti M, Bohlen J, Neehus AL, Castanos C, Gallagher R, Dorgham K, Oleastro M, Perez L, Danielian S, Dipierri JE, Casanova JL, Bustamante J, Villa M
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Pulmonary Alveolar Proteinosis and Multiple Infectious Diseases in a Child with Autosomal Recessive Complete IRF8 Deficiency

JOURNAL OF CLINICAL IMMUNOLOGY 2022 JUL; 42(5):975-985
Background Autosomal recessive (AR) complete IRF8 deficiency is a rare severe inborn error of immunity underlying an absence of blood myeloid mononuclear cells, intracerebral calcifications, and multiple infections. Only three unrelated patients have been reported. Materials and Methods We studied an Argentinian child with multiple infectious diseases and severe pulmonary alveolar proteinosis (PAP). We performed whole-exome sequencing (WES) and characterized his condition by genetic, immunological, and clinical means. Results The patient was born and lived in Argentina. He had a history of viral pulmonary diseases, disseminated disease due to bacillus Calmette-Guerin (BCG), PAP, and cerebral calcifications. He died at the age of 10 months from refractory PAP. WES identified two compound heterozygous variants in IRF8: c.55del and p.R111*. In an overexpression system, the p.R111* cDNA was loss-of-expression, whereas the c.55del cDNA yielded a protein with a slightly lower molecular weight than the wild-type protein. The mutagenesis of methionine residues downstream from c.55del revealed a re-initiation of translation. However, both variants were loss-of-function in a luciferase assay, suggesting that the patient had AR complete IRF8 deficiency. The patient had no blood monocytes or dendritic cells, associated with neutrophilia, and normal counts of NK and other lymphoid cell subsets. Conclusion We describe the fourth patient with AR complete IRF8 deficiency. This diagnosis should be considered in children with PAP, which is probably due to the defective development or function of alveolar macrophages.
Sarfo FS, Dompreh A, Asibey SO, Boateng R, Weinreich F, Kuffour EO, Norman B, Di Cristanziano V, Frickmann H, Feldt T, Eberhardt KA
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The Clinical Features and Immunological Signature of Cyclospora cayetanensis Co-Infection among People Living with HIV in Ghana

MICROORGANISMS 2022 JUL; 10(7):? Article 1407
Background: There is a paucity of information on the contemporary burden, disease patterns, and immunological profile of people living with HIV who are co-infected with C. cayetanensis in the post-antiretroviral therapy era. Methods: For this cross-sectional study, stool samples of 640 HIV-positive and 83 HIV-negative individuals in Ghana were tested for C. cayetanensis. Additionally, sociodemographic parameters, clinical symptoms, medical drug intake, and immunological parameters were assessed. Results: The prevalence of C. cayetanensis was 8.75% (n = 56) in HIV-positive and 1.20% (n = 1) in HIV-negative participants (p = 0.015). Within the group of HIV-positive participants, the prevalence reached 13.6% in patients with CD4+ T cell counts below 200 cells/mu l. Frequencies of the clinical manifestations of weight loss and diarrheal disease were significantly higher in patients with C. cayetanensis compared to those without co-infection (36.36% vs. 22.59%, p = 0.034 and 20.00% vs. 4.90%, p < 0.001, respectively). The expression of markers of immune activation and exhaustion of T lymphocyte sub-populations was significantly elevated in patients colonized with C. cayetanensis. Conclusions: In the modern post-combined antiretroviral therapy (cART) era, the acquisition of C. cayetanensis among PLWH in Ghana is driven largely by the immunosuppression profile characterized by high expression of markers of immune activation and immune exhaustion.
Tucci G, Roldan E, Gambassi A, Belousov R, Berger F, Alonso RG, Hudspeth AJ
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Modeling Active Non-Markovian Oscillations

PHYSICAL REVIEW LETTERS 2022 JUL 14; 129(3):? Article 030603
Modeling noisy oscillations of active systems is one of the current challenges in physics and biology. Because the physical mechanisms of such processes are often difficult to identify, we propose a linear stochastic model driven by a non-Markovian bistable noise that is capable of generating self-sustained periodic oscillation. We derive analytical predictions for most relevant dynamical and thermodynamic properties of the model. This minimal model turns out to describe accurately bistablelike oscillatory motion of hair bundles in bullfrog sacculus, extracted from experimental data. Based on and in agreement with these data, we estimate the power required to sustain such active oscillations to be of the order of 100 kBT per oscillation cycle.
Kannan A, Suomalainen M, Volle R, Bauer M, Amsler M, Trinh HV, Vavassori S, Schmid JP, Vilhena G, Marin-Gonzalez A, Perez R, Franceschini A, von Mering C, Hemmi S, Greber UF
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Sequence-Specific Features of Short Double-Strand, Blunt-End RNAs Have RIG-I- and Type 1 Interferon-Dependent or -Independent Anti-Viral Effects

VIRUSES-BASEL 2022 JUL; 14(7):? Article 1407
Pathogen-associated molecular patterns, including cytoplasmic DNA and double-strand (ds)RNA trigger the induction of interferon (IFN) and antiviral states protecting cells and organisms from pathogens. Here we discovered that the transfection of human airway cell lines or non-transformed fibroblasts with 24mer dsRNA mimicking the cellular micro-RNA (miR)29b-1* gives strong anti-viral effects against human adenovirus type 5 (AdV-C5), influenza A virus X31 (H3N2), and SARS-CoV-2. These anti-viral effects required blunt-end complementary RNA strands and were not elicited by corresponding single-strand RNAs. dsRNA miR-29b-1* but not randomized miR-29b-1* mimics induced IFN-stimulated gene expression, and downregulated cell adhesion and cell cycle genes, as indicated by transcriptomics and IFN-I responsive Mx1-promoter activity assays. The inhibition of AdV-C5 infection with miR-29b-1* mimic depended on the IFN-alpha receptor 2 (IFNAR2) and the RNA-helicase retinoic acid-inducible gene I (RIG-I) but not cytoplasmic RNA sensors MDA5 and ZNFX1 or MyD88/TRIF adaptors. The antiviral effects of miR29b-1* were independent of a central AUAU-motif inducing dsRNA bending, as mimics with disrupted AUAU-motif were anti-viral in normal but not RIG-I knock-out (KO) or IFNAR2-KO cells. The screening of a library of scrambled short dsRNA sequences identified also anti-viral mimics functioning independently of RIG-I and IFNAR2, thus exemplifying the diverse anti-viral mechanisms of short blunt-end dsRNAs.
Croft CA, Thaller A, Marie S, Doisne JM, Surace L, Yang R, Puel A, Bustamante J, Casanova JL, Di Santo JP
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Notch, RORC and IL-23 signals cooperate to promote multi-lineage human innate lymphoid cell differentiation

NATURE COMMUNICATIONS 2022 JUL 27; 13(1):? Article 4344
Innate lymphoid cells (ILC) are effector cells that rapidly respond to immune evading stimuli, and despite their functional diversity arise from common precursors. Authors here show how the Notch signalling pathway orchestrates ILC development from circulating human ILC precursors via RORC and its target IL-23R. Innate lymphoid cells (ILCs) include cytotoxic natural killer cells and distinct groups of cytokine-producing innate helper cells which participate in immune defense and promote tissue homeostasis. Circulating human ILC precursors (ILCP) able to generate all canonical ILC subsets via multi-potent or uni-potent intermediates according to our previous work. Here we show potential cooperative roles for the Notch and IL-23 signaling pathways for human ILC differentiation from blood ILCP using single cell cloning analyses and validate these findings in patient samples with rare genetic deficiencies in IL12RB1 and RORC. Mechanistically, Notch signaling promotes upregulation of the transcription factor RORC, enabling acquisition of Group 1 (IFN-gamma) and Group 3 (IL-17A, IL-22) effector functions in multi-potent and uni-potent ILCP. Interfering with RORC or signaling through its target IL-23R compromises ILC3 effector functions but also generally suppresses ILC production from multi-potent ILCP. Our results identify a Notch->RORC- > IL-23R pathway which operates during human ILC differentiation. These observations may help guide protocols to expand functional ILC subsets in vitro with an aim towards novel ILC therapies for human disease.
Theriault ME, Pisu D, Wilburn KM, Le-Bury G, MacNamara CW, Petrassi HM, Love M, Rock JM, VanderVen BC, Russell DG
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Iron limitation in M. tuberculosis has broad impact on central carbon metabolism

COMMUNICATIONS BIOLOGY 2022 JUL 9; 5(1):? Article 685
An inhibitor of Mycobacterium tuberculosis (Mtb) survival acts as an iron chelator, demonstrating that iron deprivation alters Mtb cholesterol and central carbon metabolism. Mycobacterium tuberculosis (Mtb), the cause of the human pulmonary disease tuberculosis (TB), contributes to approximately 1.5 million deaths every year. Prior work has established that lipids are actively catabolized by Mtb in vivo and fulfill major roles in Mtb physiology and pathogenesis. We conducted a high-throughput screen to identify inhibitors of Mtb survival in its host macrophage. One of the hit compounds identified in this screen, sAEL057, demonstrates highest activity on Mtb growth in conditions where cholesterol was the primary carbon source. Transcriptional and functional data indicate that sAEL057 limits Mtb's access to iron by acting as an iron chelator. Furthermore, pharmacological and genetic inhibition of iron acquisition results in dysregulation of cholesterol catabolism, revealing a previously unappreciated linkage between these pathways. Characterization of sAEL057's mode of action argues that Mtb's metabolic regulation reveals vulnerabilities in those pathways that impact central carbon metabolism.
Notti RQ, Walz T
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Native-like environments afford novel mechanistic insights into membrane proteins

TRENDS IN BIOCHEMICAL SCIENCES 2022 JUL; 47(7):561-569
Advances in cryogenic electron microscopy (cryo-EM) enabled routine nearatomic structure determination of membrane proteins, while nanodisc technology has provided a way to provide membrane proteins with a native or native-like lipid environment. After giving a brief history ofmembranemimetics, we present example structures of membrane proteins in nanodiscs that revealed information not provided by structures obtained in detergent. We describe how the lipid environment surrounding the membrane protein can be custom designed during nanodisc assembly and how it can be modified after assembly to test functional hypotheses. Because nanodiscs most closely replicate the physiologic environment of membrane proteins and often afford novel mechanistic insights, we propose that nanodiscs ought to become the standard for structural studies on membrane proteins.
Wang ZQ, Koirala B, Hernandez Y, Brady SF
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Discovery of Paenibacillaceae Family Gram-Negative-Active Cationic Lipopeptide Antibiotics Using Evolution-Guided Chemical Synthesis

ORGANIC LETTERS 2022 JUL 15; 24(27):4943-4948
Cationic nonribosomal lipopeptides (CNRLPs) from Paenibacillus spp. have been a rewarding source of Gramnegative-active antibiotics. Here we systematically screened sequenced bacterial genomes for CNRLP biosynthetic gene clusters (BGCs) that we predicted might encode additional Gram-negative-active antibiotics. Total chemical synthesis of the bioinformatically predicted products of seven such BGCs led to our identification of new laterocidine, tridecaptin, and paenibacterin-like antibiotics with potent activity against both multiple-drug-resistant Gram-negative and Gram-positive pathogens.
Chopra D, Arens RA, Amornpairoj W, Lowes MA, Tomic-Canic M, Strbo N, Lev-Tov H, Pastar I
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Innate immunity and microbial dysbiosis in hidradenitis suppurativa - vicious cycle of chronic inflammation

FRONTIERS IN IMMUNOLOGY 2022 JUL 28; 13(?):? Article 960488
Hidradenitis Suppurativa (HS) is a chronic multifactorial inflammatory skin disease with incompletely understood mechanisms of disease pathology. HS is characterized by aberrant activation of the innate immune system, resulting in activation of pathways that aim to protect against pathogenic microorganisms, and also contribute to failure to resolve inflammation. Imbalance in innate immunity is evident in deregulation of host antimicrobial peptides (AMPs) and the complement system associated with the microbiome dysbiosis. The pathology is further complicated by ability of pathogens associated with HS to overcome host immune response. Potential roles of major AMPs, cathelicidin, defensins, dermcidin, S100 proteins, RNAse 7 and complement proteins are discussed. Dysregulated expression pattern of innate immunity components in conjunction with bacterial component of the disease warrants consideration of novel treatment approaches targeting both host immunity and pathogenic microbiome in HS.