Innate Immune Function Research Articles

Healthy preterm newborns: Altered innate immunity and impaired monocyte function.

Birth prior to 37 completed weeks of gestation is referred to as preterm (PT). Premature newborns are at increased risk of developing infections as neonatal immunity is a developing structure. Monocytes, which are key players after birth, activate inflammasomes. Investigations into the identification of innate immune profiles in premature compared to full-term infants are limited. Our research includes the investigation of monocytes and NK cells, gene expression, and plasma cytokine levels to investigate any potential differences among a cohort of 68 healthy PT and full-term infants. According to high-dimensional flow cytometry, PT infants have higher proportions of CD56+/- CD16+ NK cells and immature monocytes, and lower proportions of classical monocytes. Gene expression revealed lower proportions of inflammasome activation after in vitro monocyte stimulation and the quantification of plasma cytokine levels expressed higher concentrations of alarmin S100A8. Our findings suggest that PT newborns have altered innate immunity and monocyte functional impairment, and pro-inflammatory plasmatic profile. This may explain PT infants' increased susceptibility to infectious disease and should pave the way for novel therapeutic strategies and clinical interventions.

A Novel Generation of Tailored Antimicrobial Drugs Based on Recombinant Multidomain Proteins.

Antibiotic resistance has exponentially increased during the last years. It is necessary to develop new antimicrobial drugs to prevent and treat infectious diseases caused by multidrug- or extensively-drug resistant (MDR/XDR)-bacteria. Host Defense Peptides (HDPs) have a versatile role, acting as antimicrobial peptides and regulators of several innate immunity functions. The results shown by previous studies using synthetic HDPs are only the tip of the iceberg, since the synergistic potential of HDPs and their production as recombinant proteins are fields practically unexplored. The present study aims to move a step forward through the development of a new generation of tailored antimicrobials, using a rational design of recombinant multidomain proteins based on HDPs. This strategy is based on a two-phase process, starting with the construction of the first generation molecules using single HDPs and further selecting those HDPs with higher bactericidal efficiencies to be combined in the second generation of broad-spectrum antimicrobials. As a proof of concept, we have designed three new antimicrobials, named D5L37βD3, D5L37D5L37 and D5LAL37βD3. After an in-depth exploration, we found D5L37D5L37 to be the most promising one, since it was equally effective against four relevant pathogens in healthcare-associated infections, such as methicillin-susceptible (MSSA) and methicillin-resistant (MRSA) Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis (MRSE) and MDR Pseudomonas aeruginosa, being MRSA, MRSE and P. aeruginosa MDR strains. The low MIC values and versatile activity against planktonic and biofilm forms reinforce the use of this platform to isolate and produce unlimited HDP combinations as new antimicrobial drugs by effective means.

RNA Polymerase III-Dependent BoNR8 and AtR8 lncRNAs Contribute to Hypocotyl Elongation in Response to Light and Abscisic Acid.

Hypocotyl elongation is inhibited by light and promoted by darkness. The plant hormone abscisic acid (ABA) also inhibits hypocotyl elongation. However, details of the molecular mechanism that regulates the integrated effects of light and ABA signaling on hypocotyl elongation remain unclear. Long non-coding RNAs (lncRNAs; >200 nt) do not encode proteins but play many physiological roles in organisms. Until now, only a few lncRNAs related to hypocotyl elongation have been reported. The lncRNAs BoNR8 (272 nt) and AtR8 (259 nt), both of which are transcribed by RNA polymerase III, are homologous lncRNAs that are abundantly present in cabbage and Arabidopsis, respectively. These lncRNAs shared 77% sequence identity, and their predicted RNA secondary structures were similar; the non-conserved nucleotides in both sequences were positioned mainly in the stem-loop regions of the secondary structures. A previous study showed that BoNR8 regulated seed germination along with ABA and that AtR8 may be involved in innate immune function in Arabidopsis. Our results show that the expression levels of BoNR8 and AtR8 were differentially affected by light and ABA and that overexpression (OX) of both BoNR8 and AtR8 in Arabidopsis regulated hypocotyl elongation depending on light and ABA.. The expression levels of light-related genes PHYB, COP1, HY5 and PIF4 and ABA-related genes ABI3 and ABI5 were altered in the AtR8-OX and BoNR8-OX lines, and, in an ABI3-defective mutant, hypocotyl elongation was greatly increased under dark condition with the addition of ABA. These results indicate that BoNR8 and AtR8 regulate hypocotyl elongation together with ABI3 and key downstream light signaling genes.

Innate Immune Zonation in the Liver: NF-κB (p50) Activation and C-Reactive Protein Expression in Response to Endotoxemia Are Zone Specific.

Hepatic innate immune function plays an important role in the pathogenesis of many diseases. Importantly, a growing body of literature has firmly established the spatial heterogeneity of hepatocyte metabolic function; however, whether innate immune function is zonated remains unknown. To test this question, we exposed adult C57BL/6 mice to endotoxemia, and hepatic tissue was assessed for the acute phase response (APR). The zone-specific APR was evaluated in periportal and pericentral/centrilobular hepatocytes isolated using digitonin perfusion and on hepatic tissue using RNAscope and immunohistochemistry. Western blot, EMSA, chromatin immunoprecipitation, and immunohistochemistry were used to determine the role of the transcription factor NF-κB in mediating hepatic C-reactive protein (CRP) expression. Finally, the ability of mice lacking the NF-κB subunit p50 (p50-/-) to raise a hepatic APR was evaluated. We found that endotoxemia induces a hepatocyte transcriptional APR in both male and female mice, with Crp, Apcs, Fga, Hp, and Lbp expression being enriched in pericentral/centrilobular hepatocytes. Focusing our work on CRP expression, we determined that NF-κB transcription factor subunit p50 binds to consensus sequence elements present in the murine CRP promoter. Furthermore, pericentral/centrilobular hepatocyte p50 nuclear translocation is temporally associated with zone-specific APR during endotoxemia. Lastly, the APR and CRP expression is blunted in endotoxemic p50-/- mice. These results demonstrate that the murine hepatocyte innate immune response to endotoxemia includes zone-specific activation of transcription factors and target gene expression. These results support further study of zone-specific hepatocyte innate immunity and its role in the development of various disease states.

Optimal Selection of IFN-α-Inducible Genes to Determine Type I Interferon Signature Improves the Diagnosis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of autoantibodies specific to self-molecules in the nucleus, cytoplasm, and cell surface. The diversity of serologic and clinical manifestations observed in SLE patients challenges the development of diagnostics and tools for monitoring disease activity. Elevated type I interferon signature (IFN- I) in SLE leads to dysregulation of innate and adaptive immune function, resulting in autoantibodies production. The most common method to determine IFN-I signature is measuring the gene expression of several IFN-α-inducible genes (IFIGs) in blood samples and calculating a score. Optimal selection of IFIGs improves the sensitivity, specificity, and accuracy of the diagnosis of SLE. We describe the mechanisms of the immunopathogenesis of IFN-I signature (IFNα production) and its clinical consequences in SLE. In addition, we explore the association between IFN-I signature, the presence of autoantibodies, disease activity, medical therapy, and ethnicity. We discuss the presence of IFN-I signature in some patients with other autoimmune diseases, including rheumatoid arthritis, systemic and multiple sclerosis, Sjogren's syndrome, and dermatomyositis. Prospective studies are required to assess the role of IFIG and the best combination of IFIGs to monitor SLE disease activity and drug treatments.

No Evidence of Long-Term Effects on Physiological Stress or Innate Immune Functioning in Northern Map Turtles a Decade After a Freshwater Oil Spill

Environmental perturbations such as chemical spills often have immediate and obvious effects on the health of ecosystems and individual organisms. However, the long-term effects of such perturbations are less evident and often less well-understood. In July 2010, a ruptured pipeline spilled diluted bitumen into the Kalamazoo River in Michigan, USA, ultimately oiling 56 km of the river channel. During spill cleanup operations, the most common vertebrate species rescued from the oiled river channel was the Northern Map Turtle (Graptemys geographica), of which over 2000 individuals were captured, cleaned of oil, and released. We returned to areas along the 2010 spill gradient to determine whether turtles from locations that had experienced different magnitudes of oiling in 2010 differed in baseline stress levels or immune functioning in 2020, which was 10 yr after the oil spill. In 2020, we collected blood samples from 100 individual Northern Map Turtles along the 2010 spill gradient and subsequently quantified the heterophil:lymphocyte ratio, bactericidal capacity, and natural antibody agglutination. We found no correlation between turtles' 2020 capture locations relative to the origin of the 2010 oil spill and either mean stress level (heterophil:lymphocyte ratio) or immune functioning (bactericidal capacity and natural antibody agglutination ability). Thus, we found no evidence that Northern Map Turtles sampled along a gradient of oil exposure resulting from the 2010 Kalamazoo River oil spill experienced long-term effects on physiological stress levels or immune functioning. Importantly, our sampling did not include any individuals that may have died during 2010–2020 from poor health after the oil spill and therefore is biased toward healthy turtles remaining in the population. Interestingly, we found that a subset of turtles known to have been oiled in 2010 actually had higher natural antibody titers than turtles sampled from a control site that presumably had never been exposed to oil. We cannot exclude the possibility of other long-term effects of the oil spill on the Map Turtle population, such as decreased reproductive output. We recommend that long-term monitoring of populations and ecosystems be included in spill mitigation plans to track the recovery of populations and ecosystems over time and to document any effects that may become evident only years after the spill event.

Salivary gland epithelial cell in Sjögren's syndrome: Metabolic shift and altered mitochondrial morphology toward an innate immune cell function

Salivary gland epithelial cells (SGEC) are the main targets of the autoimmune reactivity in Sjögren's syndrome (SS). This study aimed to investigate the core proteomic differences between SS and Control- (Ct) -derived SGEC. Proteome analysis of cultured SGEC from five SS patients and four Ct was performed in a label-free quantitation format (LFQ). Electron microscopy was applied for analysis of the mitochondrial ultrastructure of SGEC in minor salivary gland sections from six SS patients and four Ct. Four hundred seventy-four proteins were identified differentially abundant in SS- compared to Ct-SGEC. After proteomic analysis, two distinct protein expression patterns were revealed. Gene ontology (GO) pathway analysis of each protein block revealed that the cluster with highly abundant proteins in SS-SGEC showed enrichment in pathways associated with membrane trafficking, exosome-mediated transport and exocytosis as well as innate immunity related mainly to neutrophil degranulation. In contrast, the low abundance protein cluster in SS-SGEC was enriched for proteins regulating the translational process of proteins related to metabolic pathways associated to mitochondria. Electron microscopy showed decreased total number of mitochondria in SS-SGEC, which appeared elongated and swollen with less and abnormal cristae compared to Ct-SGEC mitochondria. This study defines, for the first time, the core proteomic differences of SGEC between SS and Ct, substantiates the metamorphosis of SGEC into an innate immune cell and reveals that these cells are translationally shifted towards metabolism rewiring. These metabolic alterations are related mainly to mitochondria and are mirrored in situ with heavy morphological changes.

Sub-chronic ammonia exposure induces hepatopancreatic damage, oxidative stress, and immune dysfunction in red swamp crayfish (Procambarus clarkii)

Ammonia, as one of the primary water pollutants in aquaculture, has been shown to induce a wide range of ecotoxicological effects on aquatic animals. In order to investigate the antioxidant and innate immune responses in crustaceans disrupted by ammonia, red swamp crayfish (Procambarus clarkii) were exposed to 0, 15, 30, and 50 mg/L total ammonia nitrogen for 30 d, the alterations of antioxidant responses as well as innate immunity were studied. The results showed that the severity of hepatopancreatic injury were aggravated by the increasing ammonia levels, which were mainly characterized by tubule lumen dilatation and vacuolization. The swollen mitochondria and disappeared mitochondria ridges suggested that oxidative stress induced by ammonia targets the mitochondria. Concurrently, enhanced MDA levels, and decreased GSH levels as well as the decreased transcription and activity of antioxidant enzymes, including SOD, CAT, and GPx were noticed, which suggested that high concentrations of ammonia exposure induce oxidative stress in P. clarkii. Furthermore, a significant decrease of the hemolymph ACP, AKP, and PO along with the significant downregulation of immune-related genes (ppo, hsp70, hsp90, alf1, ctl) jointly indicated that ammonia stress inhibited the innate immune function. Our findings demonstrated that sub-chronic ammonia stress induced hepatopancreatic injury and exert suppressive effects on the antioxidant capacity as well as innate immunity of P. clarkii. Our results provide a fundamental basis for the deleterious effects of ammonia stress on aquatic crustaceans.

Osteoimmunology in Periodontitis and Orthodontic Tooth Movement.

Toreview the role of the immune cells and their interaction with cells found in gingiva, periodontal ligament, and bone that leads to net bone loss in periodontitis or bone remodeling in orthodontic tooth movement. Periodontal disease is one of the most common oral diseases causing inflammation in the soft and hard tissues of the periodontium and is initiated by bacteria that induce a host response. Although the innate and adaptive immune response function cooperatively to prevent bacterial dissemination, they also play a major role in gingival inflammation and destruction of the connective tissue, periodontal ligament, and alveolar bone characteristic of periodontitis. The inflammatory response istriggered by bacteria or their products that bind to pattern recognition receptors that induce transcription factoractivityto stimulatecytokine and chemokineexpression. Epithelial, fibroblast/stromal, and resident leukocytes play a key role in initiating the host response and contribute to periodontal disease. Single-cell RNA-seq (scRNA-seq) experiments have added new insight into the roles of various cell types in the response to bacterial challenge. This response is modified by systemic conditions such as diabetes and smoking. In contrast to periodontitis, orthodontic tooth movement (OTM) is a sterile inflammatory response induced by mechanical force. Orthodontic force application stimulates acute inflammatory responses in the periodontal ligament and alveolar bone stimulated by cytokines and chemokines that produce bone resorption on the compression side. On the tension side, orthodontic forces induce the production of osteogenic factors, stimulating new bone formation. A number ofdifferent celltypes, cytokines, and signaling/pathways are involved in this complex process. Inflammatory and mechanical force-induced bone remodeling involves bone resorption and bone formation. The interaction of leukocytes with host stromal cells and osteoblastic cells plays a key role in both initiating the inflammatory events as well as inducing a cellular cascade that results in remodeling in orthodontic tooth movement or in tissue destruction in periodontitis.

Traditional and emerging Fusarium mycotoxins disrupt homeostasis of bovine mammary cells by altering cell permeability and innate immune function.

High incidence of traditional and emerging Fusarium mycotoxins in cereal grains and silages can be a potential threat to feed safety and ruminants. Inadequate biodegradation of Fusarium mycotoxins by rumen microflora following ingestion of mycotoxin-contaminated feeds can lead to their circulatory transport to target tissues such as mammary gland. The bovine udder plays a pivotal role in maintaining milk yield and composition, thus, human health. However, toxic effects of Fusarium mycotoxins on bovine mammary gland are rarely studied. In this study, the bovine mammary epithelial cell line was used as an in-vitro model of bovine mammary epithelium to investigate effects of deoxynivalenol (DON), enniatin B (ENB) and beauvericin (BEA) on bovine mammary gland homeostasis. Results indicated that exposure to DON, ENB and BEA for 48h significantly decreased cell viability in a concentration-dependent manner (P<0.001). Exposure to DON at 0.39μmol/L and BEA at 2.5μmol/L for 48h also decreased paracellular flux of FITC-40 kDa dextran (P<0.05), whereas none of the mycotoxins affected transepithelial electrical resistance after 48h exposure. The qPCR was performed for assessment of expression of gene coding tight junction (TJ) proteins, toll-like receptor 4 (TLR4) and cytokines after 4, 24 and 48h of exposure. DON, ENB and BEA significantly upregulated the TJ protein zonula occludens-1, whereas markedly downregulated claudin 3 (P<0.05). Exposure to DON at 1.35μmol/L for 4h significantly increased expression of occludin (P<0.01). DON, ENB and BEA significant downregulated TLR4 (P<0.05). In contrast, ENB markedly increased expression of cytokines interleukin-6 (IL-6) (P<0.001), tumor necrosis factor α (TNF-a) (P<0.05) and transforming growth factor-β (TGF-β) (P<0.01). BEA significantly upregulated IL- 6 (P<0.001) and TGF-β (P=0.01), but downregulated TNF-α (P<0.001). These results suggest that DON, ENB and BEA can disrupt mammary gland homeostasis by inducing cell death as well as altering its paracellular permeability and expression of genes involved in innate immune function.

Proinflammatory S100A9 stimulates TLR4/NF-κB signaling pathways causing enhanced phagocytic capacity of microglial cells

Alzheimer's disease (AD) is the main cause of dementia, affecting the increasingly aging population. Growing evidence indicates that neuro-inflammation plays crucial roles, e.g., the association between AD risk genes with innate immune functions. In this study, we demonstrate that moderate concentrations of pro-inflammatory cytokine S100A9 regulate immune response of BV2 microglial cells, i.e., the phagocytic capacity, reflected by elevated number of 1 μm diameter Dsred-stained latex beads in the cytoplasm. In contrast, at high S100A9 concentrations, both the viability and phagocytic capacity of BV2 cells drop substantially. Furthermore, it is uncovered that S100A9 affects phagocytosis of microglia via NF-κB signaling pathways. Application of related target-specific drugs, i.e., IKK and TLR4 inhibitors, effectively suppresses BV2 cells’ immune responses. These results suggest that pro-inflammatory S100A9 activates microglial phagocytosis, and possibly contributes to the clearance of amyloidogenic species at the early stage of AD.

Великий чепець білих щурів: структурно-функціональна характеристика та його роль при перитоніті

The greater omentum is now recognized as an important organ in the fight against intra-abdominal infections, so it is often called the “policeman of the peritoneal cavity”. The greater omentum plays the most important role in the implementation of immune supervision of the antigenic condition of the peritoneal fluid and rapid response of damage to the gastrointestinal tract, which is often complicated by inflammation of the peritoneum – peritonitis. The purpose of the work was to study the peculiarities of the structure of the greater omentum of white rats and its role in peritonitis by means of a bibliographic analysis of the literature. Materials and methods. This bibliographic analysis is based on published articles, books, textbooks, monographs and dissertation abstracts. For the purposes of this systematic review, a literature search was carried out in the worldwide Internet, domestic sources of literature, scientific and electronic library of Poltava State Medical University using the following key words: “morphology”, “comparative anatomy”, “greater omentum”, “greater omentum of the rats”, “immune system”, “white rats”, “laboratory animals”, “rat anatomy”, “peritonitis”. Results and discussion. The greater omentum of white rats and humans are represented by two different structures: translucent membranous regions and regions rich in adipose tissue. According to the literature, the greater omentum of white rats is the main morphological characteristic (in miniature), homologous to the human one. The main function of the greater omentum, according to the opinion of many authors and ours too, is immunity. Immune structures of the greater omentum of white rats are represented by lymphoid nodules, known in the literature as milky spots, most of which are located near arteries and veins. In pathological conditions, the greater omentum acquires absolutely special properties, such as plasticity, the ability to fuse with a traumatic and inflamed surface, the ability to hemostasis and phagocytosis, the ability to germinate and revascularize, to absorb fluids and microparticles from the peritoneal cavity, and the ability to the immunological response. Conclusion. According to the literature, the greater omentum of white rats is a miniature likeness of the greater omentum of a person. However, unlike the latter, it consists of only one duplication of the visceral peritoneum, between the leaves of which there are blood vessels with deposits of adipose tissue and milk spots. Thus, the greater omentum of white rats is a perfectly acceptable object of experimental research with the subsequent legitimate extrapolation of their results to humans. The greater omentum occupies a central place in the peritoneal defense mechanisms due to its innate immune function, high absorbing capacity, and ability to attach to neighboring structures to close defects of abdominal organs and promote their healing, due to its expressive angiogenic activity

Analysis of the effects of Rosa roxburghii Tratt fruit polyphenols on immune function in mice through gut microbiota and metabolomics: An in vivo preclinical trial study

Various plant polyphenols have been recognized by researchers as functional foods to improve the immune system. Our study showd that Rosa roxburghii Tratt fruit polyphenols (RRTP) could regulate the cellular and innate immune functions of mice. In addition, Compared with the normal control group, RRTP could affecting the balance of lymphocyte subsets. Metabolism studies showed that RRTP altered 46 different metabolites, mainly involving amino acid metabolism, carbohydrate metabolism, and lipid metabolism. Moreover, RRTP has a positive regulatory effect on the gut microbiota, the short-chain fatty acids(SCFAs) producing bacterias: Blautia, Bacteroides, Lachnospiraceae_NK4A136_group, Roseburia increased notably. Measurements of SCFAs in the cecum showed significant increases, suggesting that the immunomodulatory effects of RRTP are closely related to SCFAs. In Conclusion, RRTP could regulate the immune system of mice by regulating the balance of metabolites and intestinal microorganisms, RRTP has the potential to be developed as functional ingredients or foods to promote health.

The effects of microglia-associated neuroinflammation on Alzheimer's disease.

Alzheimer's disease (AD) is defined as a severe chronic degenerative neurological disease in human. The pathogenic mechanism of AD has been convincingly elucidated by the "amyloid cascade hypothesis" with the main focus of the pathological accretion of β-amyloid (Aβ) peptides outside the cell. However, increasing evidence suggests that this hypothesis is weak in explaining the pathogenesis of AD. Neuroinflammation is crucial in the development of AD, which is proven by the elevated levels of inflammatory markers and the identification of AD risk genes relevant to the innate immune function. Here, we summarize the effects of microglia-mediated neuroinflammation on AD, focusing on the temporal and spatial changes in microglial phenotype, the interactions among microglia, Aβ, tau, and neurons, and the prospects and recent advances in neuroinflammation as a diagnostic and therapeutic target of AD.

The role of anti-E. coli antibody from maternal colostrum on the colonization of newborn dairy calves gut with Escherichia coli and the development of clinical diarrhea

Escherichia coli (E. coli) is an early organism in the colonization of mucosal tissue and has an influence on the development of mucosal and systemic inflammatory responses. To understand the impact of transfer of Immunoglobulin G (IgG), E. coli-specific antibody and general immune factors to the calf on the gut microbiota, an observational study that followed the temporal colonization of the intestine with E. coli as correlated with the total quantity of IgG and the antibody recognizing E. coli, was conducted in newborn Holstein calves. The calves were subjected to the “gold standard” of colostrum management, including dam vaccination prior to delivery to prime colostrum. Twenty Holstein dams, producing an adequate quantity of good-quality colostrum following uncomplicated deliveries of healthy female offspring, were utilized in this study. Each calf was monitored and scored daily for diarrhea. Blood and fecal samples were collected from calves on day (D) D1 (before colostrum intake), then D3, D7, D14 and D28 after colostrum feeding. E. coli isolated from fecal samples of the calves were assessed for virulence genes and the quantity per gram of feces using conventional Polymerase chain reaction and Real-time polymerase chain reaction quantitative, respectively. The total quantity of plasma IgG and the titer of E. coli-binding antibody were measured by enzyme-linked immunosorbent assay. The peak in diarrhea in the calves was observed on D12. No IgG or E. coli-binding antibody were detected prior to colostrum intake (D1). Both total IgG and binding antibody sharply increased by D3. Total and binding IgG declined with calf age. The total number of bacteria (16S rRNA) in feces was similar between D1 and D14. The number of total bacteria increased over the period from D14 to D28. The number of E. coli was minimal on D1. The number of E. coli increased during the period D3-D7. A decrease in the number of E. coli per gram of feces declines between D14and D28. The stable toxin gene was frequently identified in the E. coli isolated from the calves. Further, E. coli K99 was not identified in this study. While the gut was colonized by E. coli early in life corresponding to the peak level of IgG and specific antibody, a decreasing number of E. coli were observed as the passive immunity waned. This suggests that the function of the passive antibody may be to control colonization and seed innate immune function that then stabilizes the level of E. coli in the digestive tract of calves.

Transcriptomic and Metabolomic Studies Reveal That Toll-like Receptor 2 Has a Role in Glucose-Related Metabolism in Unchallenged Zebrafish Larvae (Danio rerio).

Toll-like receptors (TLRs) have been implicated in the regulation of various metabolism pathways, in addition to their function in innate immunity. Here, we investigate the metabolic function of TLR2 in a larval zebrafish system. We studied larvae from a tlr2 mutant and the wild type sibling controls in an unchallenged normal developmental condition using transcriptomic and metabolomic analyses methods. RNAseq was used to evaluate transcriptomic differences between the tlr2 mutant and wild-type control zebrafish larvae and found a signature set of 149 genes to be significantly altered in gene expression. The expression level of several genes was confirmed by qPCR analyses. Gene set enrichment analysis (GSEA) revealed differential enrichment of genes between the two genotypes related to valine, leucine, and isoleucine degradation and glycolysis and gluconeogenesis. Using 1H nuclear magnetic resonance (NMR) metabolomics, we found that glucose and various metabolites related with glucose metabolism were present at higher levels in the tlr2 mutant. Furthermore, we confirmed that the glucose level is higher in tlr2 mutants by using a fluorometric assay. Therefore, we have shown that TLR2, in addition to its function in immunity, has a function in controlling metabolism during vertebrate development. The functions are associated with transcriptional regulation of various enzymes involved in glucose metabolism that could explain the different levels of glucose, lactate, succinate, and malate in larvae of a tlr2 mutant.

Lipocalin-2 deletion attenuates lipopolysaccharide-induced acute lung inflammation via downregulating chemotaxis-related genes

Lipocalin-2 (LCN2) is an acute phase protein used as a biomarker for acute lung injury (ALI). Although the innate immune functions of LCN2 have been studied, how LCN2 contributes to ALI induced by lipopolysaccharide (LPS) remains unknown. In this study, we investigated the effect of LCN2 deletion on LPS-induced ALI using RNA-sequencing. LPS-treated LCN2 knockout (KO) mice had a decreased histopathological score and reduced neutrophil and macrophage infiltration in lung tissue compared with LPS-treated WT mice. RNA-sequencing analysis identified 38 differentially expressed genes (DEGs), including Cxcl5, Cxcl13, Xcl1, Saa1, and Cd14. In particular, Gene Ontology analysis of DEGs revealed a significant reduction in the inflammatory response, neutrophil chemotaxis, and chemokine-mediated signaling in LPS-treated LCN2KO mice compared with LPS-treated WT mice. Thus, these results suggest that LCN2 deletion alleviates LPS-induced ALI and that LCN2 may be involved in chemotaxis-related gene expression.

Holding time has limited impact on constitutive innate immune function in a long-lived Antarctic seabird, the Adélie penguin: implications for field studies.

There is great interest in measuring immune function in wild animals. Yet, field conditions often have methodological challenges related to handling stress, which can alter physiology. Despite general consensus that immune function is influenced by handling stress, previous studies have provided equivocal results. Furthermore, few studies have focused on long-lived species, which may have different stress-immune trade-offs compared to short-lived species that have primarily been tested. Here, we investigate whether capture and handling duration impacts innate immune function in a long-lived seabird, the Adélie penguin (Pygoscelis adeliae). We found no evidence for changes in three commonly used parameters of innate immune function upon holding time of up to 2h, suggesting that immune function in this species is more robust against handling than in other species. This opens up exciting possibilities for measuring immune function in species with similar life-histories even if samples cannot be taken directly after capture.

The effect of a methyl group on structure and function: Serine vs. threonine glycosylation and phosphorylation.

A variety of glycan structures cover the surface of all cells and are involved in myriad biological processes, including but not limited to, cell adhesion and communication, protein quality control, signal transduction and metabolism, while also being intimately involved in innate and adaptive immune functions. Immune surveillance and responses to foreign carbohydrate antigens, such as capsular polysaccharides on bacteria and surface protein glycosylation of viruses, are the basis of microbial clearance, and most antimicrobial vaccines target these structures. In addition, aberrant glycans on tumors called Tumor-Associated Carbohydrate Antigens (TACAs) elicit immune responses to cancer, and TACAs have been used in the design of many antitumor vaccine constructs. A majority of mammalian TACAs are derived from what are referred to as mucin-type O-linked glycans on cell-surface proteins and are linked to the protein backbone through the hydroxyl group of either serine or threonine residues. A small group of structural studies that have compared mono- and oligosaccharides attached to each of these residues have shown that there are distinct differences in conformational preferences assumed by glycans attached to either "unmethylated" serine or ß-methylated threonine. This suggests that the linkage point of antigenic glycans will affect their presentation to the immune system as well as to various carbohydrate binding molecules (e.g., lectins). This short review, followed by our hypothesis, will examine this possibility and extend the concept to the presentation of glycans on surfaces and in assay systems where recognition of glycans by proteins and other binding partners can be defined by different attachment points that allow for a range of conformational presentations.

Photopharmacological dissociation of transcriptional activation and degranulation of mast cells.

Besides a key role in allergic diseases, mast cells confer important modulatory functions in innate and adaptive immunity. The communication between mast cells and other immune cells is not only based on the acute or long-term release of pre-stored mediators involving distinct processes of degranulation but also on the expression of specific surface proteins. Activation of mast cells typically involves Ca2+ signalling, which evokes both transcriptional activation and degranulation. To dissect the complex functions of mast cells in human pathology and to explore new therapeutic strategies we aimed towards specific manipulation of mast cell phenotype. Characterization of an optochemogenetic protocol for activation RBL-2H3 mast cells revealed that repetitive photocycling of OptoBI-1 to generate oscillatory Ca2+ signals elicits rapid and efficient NFAT nuclear translocation without concomitant degranulation. By contrast, conventional pharmacological activation of overexpressed TRPC6 channel was strictly associated with CD63-associated secretion. Our results suggest that the specific modulation of mast cell phenotype as obtained by TRPC6-OptoBI-1-mediated activation, arises from introduction of a highly specific conformational and functional state of the TRPC6 channel, resulting in unique Ca2+signatures. Further understanding of these phenomena may lead to new approaches for (photo)pharmacological immunomodulation.