Direct recognition of invading pathogens by innate immune cells is a critical driver of the inflammatory response. However, cells of the innate immune system can also sense their local ...microenvironment and respond to physiological fluctuations in temperature, pH, oxygen and nutrient availability, which are altered during inflammation. Although cells of the immune system experience force and pressure throughout their life cycle, little is known about how these mechanical processes regulate the immune response. Here we show that cyclical hydrostatic pressure, similar to that experienced by immune cells in the lung, initiates an inflammatory response via the mechanically activated ion channel PIEZO1. Mice lacking PIEZO1 in innate immune cells showed ablated pulmonary inflammation in the context of bacterial infection or fibrotic autoinflammation. Our results reveal an environmental sensory axis that stimulates innate immune cells to mount an inflammatory response, and demonstrate a physiological role for PIEZO1 and mechanosensation in immunity.
The annotation of the mammalian protein-coding genome is incomplete. Arbitrary size restriction of open reading frames (ORFs) and the absolute requirement for a methionine codon as the sole initiator ...of translation have constrained the identification of potentially important transcripts with non-canonical protein-coding potential
. Here, using unbiased transcriptomic approaches in macrophages that respond to bacterial infection, we show that ribosomes associate with a large number of RNAs that were previously annotated as 'non-protein coding'. Although the idea that such non-canonical ORFs can encode functional proteins is controversial
, we identify a range of short and non-ATG-initiated ORFs that can generate stable and spatially distinct proteins. Notably, we show that the translation of a new ORF 'hidden' within the long non-coding RNA Aw112010 is essential for the orchestration of mucosal immunity during both bacterial infection and colitis. This work expands our interpretation of the protein-coding genome and demonstrates that proteinaceous products generated from non-canonical ORFs are crucial for the immune response in vivo. We therefore propose that the misannotation of non-canonical ORF-containing genes as non-coding RNAs may obscure the essential role of a multitude of previously undiscovered protein-coding genes in immunity and disease.
Influenza A virus (IAV) causes up to half a million deaths worldwide annually, 90% of which occur in older adults. We show that IAV-infected monocytes from older humans have impaired antiviral ...interferon production but retain intact inflammasome responses. To understand the in vivo consequence, we used mice expressing a functional Mx gene encoding a major interferon-induced effector against IAV in humans. In Mx1-intact mice with weakened resistance due to deficiencies in Mavs and TIr7, we found an elevated respiratory bacterial burden. Notably, mortality in the absence of Mavs and TIr7 was independent of viral load or MyD88-dependent signaling but dependent on bacterial burden, caspase-1/11, and neutrophil-dependent tissue damage. Therefore, in the context of weakened antiviral resistance, vulnerability to IAV disease is a function of caspase-dependent pathology.
The biogeography of the mammalian intestine is remarkable in that a vast microbial consortium exists inside the organism, surrounded by intestinal epithelial cells. The microbiome and the intestinal ...epithelium have developed a complex network of interactions that maintain intestinal homeostasis. We now recognize that functions of the epithelium are compartmentalized in specific intestinal epithelial cell subtypes. Furthermore, we are beginning to understand the ways in which microbes and their metabolic products impact the specific epithelial subsets. Here, we survey the mechanisms utilized by the microbiome to regulate intestinal epithelial function, and inversely, how different epithelial cell subtypes cooperate in regulating the microbiome.
Mucosal barrier immunity is essential for the maintenance of the commensal microflora and combating invasive bacterial infection. Although immune and epithelial cells are thought to be the canonical ...orchestrators of this complex equilibrium, here, we show that the enteric nervous system (ENS) plays an essential and non-redundant role in governing the antimicrobial protein (AMP) response. Using confocal microscopy and single-molecule fluorescence in situ mRNA hybridization (smFISH) studies, we observed that intestinal neurons produce the pleiotropic cytokine IL-18. Strikingly, deletion of IL-18 from the enteric neurons alone, but not immune or epithelial cells, rendered mice susceptible to invasive Salmonella typhimurium (S.t.) infection. Mechanistically, unbiased RNA sequencing and single-cell sequencing revealed that enteric neuronal IL-18 is specifically required for homeostatic goblet cell AMP production. Together, we show that neuron-derived IL-18 signaling controls tissue-wide intestinal immunity and has profound consequences on the mucosal barrier and invasive bacterial killing.
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•Epithelial and immune cell IL-18 are not required to combat S. typhimurium•Enteric neurons express IL-18•Enteric neuronal IL-18 controls goblet cell antimicrobial protein expression•Neuronal IL-18 directs killing of enteric bacterial pathogens
IL-18 produced by the enteric nervous system (ENS) is crucial for host protection against Salmonella infection via goblet cell antimicrobial peptide production, highlighting the ENS as a crucial immune mediator in bacterial defense.
Elicitors are stressors of biotic nature responsible for the adaptation of plants to cope with environmental stresses. Brassicae species (as white mustard) produce glucosinolates (GSs) that modify ...soil microbial communities and suppress soil-borne plant diseases. This research aimed to evaluate the glucosinolates levels in white mustard after elicitation with salicylic acid (SA), hydrogen peroxide (H
2
O
2
), chitosan (QN), and a commercial oligosaccharide (Xh), as well as the impact on the biofumigant activity of elicited plant residues mixed with fresh manure against soil-borne populations of
Fusarium oxysporum
. White mustard plants were treated with SA, H
2
O
2
, QN, and Xh. White mustard residues of the QN treatment (100 mg/mL) were further evaluated either in combination or not with fresh cow manure for biofumigant activity against
F. oxysporum
. Spectrophotometric and GC–MS techniques, respectively, determined GSs in white mustard plant organs. Significant increases in GSs in all plant organs except roots were found. The best treatment was chitosan 100 mg/mL, showing increases in leaves, flowers, and seeds. These plants treated with chitosan and mixed with fresh cow manure used in the biofumigation of soils displayed a reduction from 1600 CFU/g of soil to 50 CFU/g of soil
F. oxysporum
native population. Results suggested that controlled elicitation might increase the amount of GSs on white mustard, especially in the aerial parts; thus, elicited white mustard can be valorized as a potent biofumigant when mixed with fresh cow manure; thus, these green amendments might be a sustainable alternative in agriculture to help in crop management.
Mice with a functional human immune system serve as an invaluable tool to study the development and function of the human immune system in vivo. A major technological limitation of all current ...humanized mouse models is the lack of mature and functional human neutrophils in circulation and tissues. To overcome this, we generated a humanized mouse model named MISTRGGR, in which the mouse granulocyte colony-stimulating factor (G-CSF) was replaced with human G-CSF and the mouse G-CSF receptor gene was deleted in existing MISTRG mice. By targeting the G-CSF cytokine-receptor axis, we dramatically improved the reconstitution of mature circulating and tissue-infiltrating human neutrophils in MISTRGGR mice. Moreover, these functional human neutrophils in MISTRGGR are recruited upon inflammatory and infectious challenges and help reduce bacterial burden. MISTRGGR mice represent a unique mouse model that finally permits the study of human neutrophils in health and disease.
Nine terpenoids were isolated from the leaves and flowers of Salvia amarissima, including a new acylated diterpenoid glucoside, amarisolide F (1), a new neo-clerodane diterpenoid, amarissinin D (2), ...which was isolated as an acetyl derivative (2a), and four known diterpenoids. The structure of amarisolide F (1) was elucidated by NMR and MS data analyses, as well as its methanolysis products 7 and 8, which also constituted new diterpenoids, named amarissinin E and 8-epi-amarissinin E, respectively. The absolute configuration of compound 7 was established by single-crystal X-ray diffraction. The cytotoxicity and anti-MDR effect of 1 in three phenotypes of the MCF-7 cell lines were assayed. Compound 1 was 2–3.6-fold more active than amarissinins A (3) and B (4), but several orders of magnitude less active than teotihuacanin (6) and reserpine.
Mutations the in human DJ-1 (hDJ-1) gene are associated with early-onset autosomal recessive forms of Parkinson's disease (PD). hDJ-1/parkinsonism associated deglycase (PARK7) is a cytoprotective ...multi-functional protein that contains a conserved cysteine-protease domain. Given that cysteine-proteases can act on both amide and ester substrates, we surmised that hDJ-1 possessed cysteine-mediated esterase activity. To test this hypothesis, hDJ-1 was overexpressed, purified and tested for activity towards 4-nitrophenyl acetate (pNPA) as µmol of pNPA hydrolyzed/min/mg·protein (U/mg protein). hDJ-1 showed maximum reaction velocity esterase activity (Vmax = 235.10 ± 12.00 U/mg protein), with a sigmoidal fit (S0.5 = 0.55 ± 0.040 mM) and apparent positive cooperativity (Hill coefficient of 2.05 ± 0.28). A PD-associated mutant of DJ-1 (M26I) lacked activity. Unlike its protease activity which is inactivated by reactive oxygen species (ROS), esterase activity of hDJ-1 is enhanced upon exposure to low concentrations of hydrogen peroxide (<10 µM) and plateaus at elevated concentrations (>100 µM) suggesting that its activity is resistant to oxidative stress. Esterase activity of DJ-1 requires oxidation of catalytic cysteines, as chemically protecting cysteines blocked its activity whereas an oxido-mimetic mutant of DJ-1 (C106D) exhibited robust esterase activity. Molecular docking studies suggest that C106 and L126 within its catalytic site interact with esterase substrates. Overall, our data show that hDJ-1 contains intrinsic redox-sensitive esterase activity that is abolished in a PD-associated mutant form of the hDJ-1 protein.
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