The neuropeptide receptor subunit RAMP1 constrains the innate immune response during acute pancreatitis in mice

OBJECTIVES

The importance of the Calcitonin-gene-related-peptide-pathway (CGRP) as neuronal modulator of innate immune responses in mice has been previously demonstrated. The CGRP-receptor is composed of two subunits: the receptor-activity-modifying-protein-1 (RAMP1) and the calcitonin-receptor-like-receptor (CLR). CGRP can influence immune cells and their capacity of producing inflammatory cytokines. Using a RAMP1 knockout-mouse (RAMP1^-/-) we examined the role of the CGRP-receptor in the acute-phase of cerulein-induced pancreatitis.

METHODS

Hourly cerulein-injections for a period of 8 h in RAMP1^-/- and wild-type mice were performed. To compare severity and extent of inflammation in RAMP1^-/- and wild-type mice, histological analyses were done and cytokine levels were assessed using qRT-PCR 8 h, 24 h, 2 days, and 7 days post-cerulein-treatment. Furthermore, serum activities of LDH and lipase were determined.

RESULTS

After 8 h RAMP1^-/- mice showed a higher pancreas-to-body-weight-ratio, increased tissue edema and immune cell infiltration with higher amount of F4/80-positive cells as compared to wild-type mice. Overall infiltration of immune cells at 24 h was increased in RAMP1^-/- mice and composed predominantly of MPO-positive neutrophils. In addition, after 24 h RAMP1^-/- mice presented a higher pancreas-to-body-weight-ratio, higher expression of Ccl3, Il6, and Il1b and increased number of cleaved caspase 3 positive cells. Serum lipase correlated with the extent of tissue damage in RAMP1^-/- compared to wild-type mice 24 h post-cerulein treatment.

CONCLUSION

Mice lacking RAMP1 showed increased inflammation, tissue edema, and pancreas injury particularly in the early phase of acute pancreatitis. This study highlights the essential role of CGRP for dampening the innate immune response in acute pancreatitis.

Effect of symbiotic supplemented diet on innate-adaptive immune response, cytokine gene regulation and antioxidant property in Labeo rohita against Aeromonas hydrophila

Administration of probiotic, prebiotic or symbiotic supplemented diets boosts the antioxidant property, pro and/or anti-inflammatory cytokine gene transcription, innate-adaptive immunity, growth rate and feed digestibility with very low or no mortality in healthy and infected (both groups) in Labeo rohita against Aeromonas hydrophila is reported. The probiotic diet increased the white blood cell (WBC) count and globulin (GB) level significantly on or after 6th week whereas with the symbiotic diet the increase was noted two weeks earlier in both groups; the total protein (TP) level also increased significantly when fed with probiotic diet on weeks 6 and 8, whereas with symbiotic diet the significant increase manifested earlier at 4th week itself. The serum phagocytic activity (PA), respiratory burst activity (RBA), complement C3 (CC3) level, alternative complement pathway (ACP), lysozyme activity (LA), and immunoglobulin M (IgM) levels in head kidney (HK) leucocytes increased significantly (P < 0.05) in both groups fed with probiotic diet on weeks 6 and 8; with symbiotic diet from weeks 2-8; but with prebiotic diet only on 8th week. With probiotic diet the superoxide dismutase (SOD) and catalase (CAT) activities increased significantly (P < 0.05) on weeks 6 and 8; with symbiotic diet from weeks 4-8 but the prebiotics diet only on 8th week. However, glutathione peroxidase (GPx) activity increased significantly (P < 0.05) with probiotic diet on weeks 6 and 8 and with symbiotic diet from weeks 4-8. When healthy fish fed with any supplementation diet for a period of 30 days there was no mortality while 5%, 10%, and 10% mortality was observed in infected group fed with symbiotic, probiotic, and prebiotic supplementation diets. In head kidney (HK) leucocytes, the IL-1β, IL-8, TNF-α, and NF-κB gene transcriptions were significantly up-regulation in both groups when fed with probiotic diet on weeks 6 and 8, symbiotic diet from weeks 4-8 while the prebiotic diet only on 8th week. The iNOS expression was up-regulation significantly in both groups fed with probiotic and symbiotic diets on weeks 6 and 8; however, with any diet, the relative IL-10 and TGF-β gene expressions were down-regulated. The present study suggested that dietary administration of symbiotic diet elicited earlier antioxidant activity, innate-adaptive immune response, immune related cytokine gene modulation, and disease protection earlier i.e. on 4th week than with probiotic or prebiotic diets in L. rohita against A. hydrophila.

Single Nucleotide Polymorphisms in Chemosensory Pathway Genes GNB3, TAS2R19, and TAS2R38 Are Associated with Chronic Rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is a multifaceted disease with a significant genetic component. The importance of taste receptor signaling has recently been highlighted in CRS; single nucleotide polymorphisms (SNPs) of bitter tastant-responsive G-protein-coupled receptors have been linked with CRS and with altered innate immune responses to multiple bacterially derived signals.

OBJECTIVE

To determine in CRS the frequency of six SNPs in genes with known bitter tastant signaling function.

METHODS

Genomic DNA was isolated from 74 CRS volunteers in West Virginia, and allele frequency was determined and compared with demographically matched data from the 1,000 Genomes database.

RESULTS

For two SNPs in a gene recently associated with bitterant signaling regulation, RGS21, there were no associations with CRS (although the frequency of the minor allele of RGS21, rs7528947, was seen to increase with increasing Lund-Mackay CT staging score). Two TAS2R bitter taste receptor gene variants (TAS2R19 rs10772420 and TAS2R38 rs713598), identified in prior CRS genetics studies, were found to have similar associations in this study.

CONCLUSION

Unique to our study is the establishment of an association between CRS in this patient population and GNB3 SNP rs5443, a variation in an established G protein component downstream of bitterant receptor signal transduction.

Phagocytosis of live and dead Escherichia coli and Staphylococcus aureus in human whole blood is markedly reduced by combined inhibition of C5aR1 and CD14

BACKGROUND

Sepsis is a dysregulated host response to infection. The aim of this study was to investigate the effects of complement- and CD14 inhibition on phagocytosis of live and dead Gram-negative and Gram-positive bacteria in human whole blood.

METHODS

Lepirudin-anticoagulated blood was incubated with live or dead E. coli or S. aureus at 37 °C for 120 min with or without the C5aR1 antagonist PMX53 and/or anti-CD14. Granulocyte and monocyte phagocytosis were measured by flow cytometry, and five plasma cytokines by multiplex, yielding a total of 28 mediators of inflammation tested for.

RESULTS

16/28 conditions were reduced by PMX53, 7/28 by anti-CD14, and 24/28 by combined PMX53 and CD14 inhibition. The effect of complement inhibition was quantitatively more pronounced, in particular for the responses to S. aureus. The effect of anti-CD14 was modest, except for a marked reduction in INF-β. The responses to live and dead S. aureus were equally inhibited, whereas the responses to live E. coli were inhibited less than those to dead E. coli.

CONCLUSION

C5aR1 inhibited phagocytosis-induced inflammation by live and dead E. coli and S. aureus. CD14 blockade potentiated the effect of C5aR1 blockade, thus attenuating inflammation.

Immunologic Targeting of Cancer Stem Cells

Cancer stem cells (CSCs) are crucial for tumor recurrence and distant metastasis. Immunologically targeting CSCs represents a promising strategy to improve efficacy of multimodal cancer therapy. Modulating the innate immune response involving Toll-like receptors, macrophages, natural killer cells, and γδT cells has therapeutic effects on CSCs. Antigens expressed by CSCs provide specific targets for immunotherapy. CSC-primed dendritic cell-based vaccines have induced significant antitumor immunity as an adjuvant therapy in experimental models of established tumors. Targeting the tumor microenvironment CSC niche with cytokines or checkpoint blockade provides additional strategies to eliminate CSCs.

Effects of aloe-emodin on innate immunity, antioxidant and immune cytokines mechanisms in the head kidney leucocytes of Labeo rohita against Aphanomyces invadans

The effect of aloe-emodin incorporated diets on innate immune response, disease resistance, pro and/or anti-inflammatory cytokine gene transcription in Labeo rohita against Aphanomyces invadans is reported for the first time. In healthy and infected groups fed with 5 mg aloe-emodin enriched diet the white blood cell (WBC) count increased significantly (p > 0.05) after 6th week. In both groups fed with any enriched diet the biochemical parameters such as albumin, globulin, and albumin/globulin ratio did not vary significantly; however with 5 mg aloe-emodin diet the albumin and globulin levels increased significantly (p > 0.05) after 6th week. The serum phagocytic activity (PA), respiratory burst activity (RBA), serum complement C3 (CC3), and lysozyme activity (LA) did not increase with any diet between weeks 2 and 4, whereas with 5 mg aloe-emodin diet increased significantly in both groups after 6th week. The pro-inflammatory cytokines such as IL-1β, IL-8, TNF-α, and iNOS significantly modulated the expression in both groups on being fed with 5 mg aloe-emodin incorporation diet on 8th week. Healthy fish fed with any aloe-emodin diet did not suffer mortality. However, the infected fish fed with 1, 5, and 10 mg kg^-1 aloe-emodin diets registered 5%, 10%, and 15% mortality. The present study indicates that healthy and infected L. rohita exhibited enhanced innate immune response, disease resistance, pro and/or anti-inflamatory cytokine gene transcription levels against A. invadans.

Interferon-stimulated gene 15 (ISG15) restricts Zika virus replication in primary human corneal epithelial cells

PURPOSE

Zika virus (ZIKV) has emerged as an important human pathogen causing ocular complications. There have been reports of the shedding of ZIKV in human as well as animal tears. In this study, we investigated the infectivity of ZIKV in corneal epithelial cells and their antiviral immune response.

METHODS

Primary human corneal epithelial cells (Pr. HCECs) and an immortalized cell line (HUCL) were infected with two different strains of ZIKV (PRVABC59 & BeH823339) or dengue virus (DENV, serotypes 1-4). Viral infectivity was assessed by immunostaining of viral antigen and plaque assay. qRT-PCR and immunoblot analyses were used to assess the expression of innate inflammatory and antiviral genes. Supplementation of recombinant ISG15 (rISG15) and gene silencing approaches were used to elucidate the role of ISG15 in corneal antiviral defense.

RESULTS

Pr. HCECs, but not the HUCL cells, were permissive to both ZIKV strains and specifically to DENV3 infection. ZIKV induced the expression of viral recognition receptors (TLR3, RIG-I, &MDA5), and genes involved in inflammatory (CXCL10 & CCL5) and antiviral (IFNs, MX1, OAS2, ISG15) responses in Pr. HCECs. Furthermore, ZIKV infection caused Pr. HCECs cell death, as evidenced by TUNEL staining. Silencing of ISG15 increased ZIKV infectivity while supplementation with rISG15 reduced ZIKV infection by direct inactivation of ZIKV and inhibiting its entry.

CONCLUSIONS

Our study demonstrates for the first time, that ZIKV can readily infect and replicate in Pr. HCECs. Therefore, ZIKV may persist in the cornea and pose the potential risk of transmission via corneal transplantation.

Evaluating the Role of Microglial Cells in Clearance of Aβ from Alzheimer's Brain

Ever increasing incidence of Alzheimer's diseases (AD) has been reported all over the globe, and practically no drug is currently available for its treatment. In the past 15 years, not a single drug came out of clinical trials. The researchers have yet to discover a drug that could specifically target AD; in fact, the drugs that are about to launch in the global market either belong to natural compounds or are already approved drugs targeting other diseases. So, we need to shift our focus on finding novel targets which are more specific and could either detect or inhibit the disease progression at a very early stage. Microglia are the only resident innate immune cells of the brain that are originated from erythromyeloid progenitors. They migrate to the brain during early embryonic development, although their number is less (∼5 to 10%), but they could act as guardians of the brain. It has been shown that the extracellular deposits of Aβ are continuously phagocytosed by microglia in healthy individuals, but this ability would decrease with age and lead to development of AD. In this review, we have explored the possibility of whether microglial cells could be utilized as an early predictor of the AD progression. Here, we discuss the innate immune response of microglial cells, the factors affecting microglia response, microglial receptors to which Aβ could bind, and microglial phenotype markers. Last, we conclude with a list of available AD therapeutics along with their mechanism.

Spiropyran as a potential molecular diagnostic tool for double-stranded RNA detection

Background

Long double-stranded RNAs (dsRNAs) are duplex RNAs that can induce immune response when present in mammalian cells. These RNAs are historically associated with viral replication, but recent evidence suggests that human cells naturally encode endogenous dsRNAs that can regulate antiviral machineries in cellular contexts beyond immune response.

Results

In this study, we use photochromic organic compound spiropyran to profile and quantitate dsRNA expression. We show that the open form of spiropyran, merocyanine, can intercalate between RNA base pairs, which leads to protonation and alteration in the spectral property of the compound. By quantifying the spectral change, we can detect and quantify dsRNA expression level, both synthetic and cellular. We further demonstrate that spiropyrans can be used as a molecular diagnostic tool to profile endogenously expressed dsRNAs. Particularly, we show that spiropyrans can robustly detect elevated dsRNA levels when colorectal cancer cells are treated with 5-aza-2'-deoxycytidine, an FDA-approved DNA-demethylating agent used for chemotherapy, thus demonstrating the use of spiropyran for predicting responsiveness to the drug treatment.

Conclusion

As dsRNAs are signature of virus and accumulation of dsRNAs is implicated in various degenerative disease, our work establishes potential application of spiropyrans as a simple spectral tool to diagnose human disease based on dsRNA expression.

Prebiotic supplementation in frail older people affects specific gut microbiota taxa but not global diversity

BACKGROUND

There are complex interactions between aging, frailty, diet, and the gut microbiota; modulation of the gut microbiota by diet could lead to healthier aging. The purpose of this study was to test the effect of diets differing in sugar, fat, and fiber content upon the gut microbiota of mice humanized with microbiota from healthy or frail older people. We also performed a 6-month dietary fiber supplementation in three human cohorts representing three distinct life-stages.

METHODS

Mice were colonized with human microbiota and then underwent an 8-week dietary intervention with either a high-fiber/low-fat diet typical of elderly community dwellers or a low-fiber/high-fat diet typical of long-stay residential care subjects. A cross-over design was used where the diets were switched after 4 weeks to the other diet type to identify responsive taxa and innate immunity changes. In the human intervention, the subjects supplemented their normal diet with a mix of five prebiotics (wheat dextrin, resistant starch, polydextrose, soluble corn fiber, and galactooligo-saccharide) at 10 g/day combined total, for healthy subjects and 20 g/day for frail subjects, or placebo (10 g/day maltodextrin) for 26 weeks. The gut microbiota was profiled and immune responses were assayed by T cell markers in mice, and serum cytokines in humans.

RESULTS

Humanized mice maintained gut microbiota types reflecting the respective healthy or frail human donor. Changes in abundance of specific taxa occurred with the diet switch. In mice with the community type microbiota, the observed differences reflected compositions previously associated with higher frailty. The dominance of Prevotella present initially in community inoculated mice was replaced by Bacteroides, Alistipes, and Oscillibacter. Frail type microbiota showed a differential effect on innate immune markers in both conventional and germ-free mice, but a moderate number of taxonomic changes occurring upon diet switch with an increase in abundance of Parabacteroides, Blautia, Clostridium cluster IV, and Phascolarctobacterium. In the human intervention, prebiotic supplementation did not drive any global changes in alpha- or beta-diversity, but the abundance of certain bacterial taxa, particularly Ruminococcaceae (Clostridium cluster IV), Parabacteroides, Phascolarctobacterium, increased, and levels of the chemokine CXCL11 were significantly lower in the frail elderly group, but increased during the wash-out period.

CONCLUSIONS

Switching to a nutritionally poorer diet has a profound effect on the microbiota in mouse models, with changes in the gut microbiota from healthy donors reflecting previously observed differences between elderly frail and non-frail individuals. However, the frailty-associated gut microbiota did not reciprocally switch to a younger healthy-subject like state, and supplementation with prebiotics was associated with fewer detected effects in humans than diet adjustment in animal models.

Dietary nucleotides can directly stimulate the immunity of zebrafish independent of the intestinal microbiota

In this study, we firstly tested the effects of dietary nucleotides on the disease resistance and innate immunity of zebrafish. Further, we investigated the role of intestinal microbiota in the nucleotides-induced immunostimulatory effect by using a germ-free zebrafish model and microbiota transfer technique. Fish were fed control or nucleotides (NT)-supplemented diets (at 0.05%,0.1%, 0.15% or 0.2%, m/m) for 4 weeks, followed by immersion challenge with Aeromonas hydrophila NJ-1. The results showed that 0.1% NT group enhanced the resistance of zebrafish against A. hydrophila infection. We further observed that the relative expressions of mucin, claudin16, occlusin1, hepcidin, defensin beta-like, myeloperoxidase (Mpo), and serum amyloid A (Saa) increased in the 0.1% NT group compared with control (P < 0.05), indicating that dietary nucleotides enhanced the physical barrier and mucosal immunity in the intestine of zebrafish. Moreover, ROS level in the head kidney was significantly increased in NT fed zebrafish versus control (P < 0.05), indicating enhanced systematic immunity. Furthermore, dietary NT significantly elevated the relative expressions of mpo, saa and the ROS activity in germ-free zebrafish, while germ-free zebrafish colonized with NT-altered microbiota had no significant difference in the relative expressions of mpo, saa and the ROS activity compared with the control microbiota-colonized fish, suggesting that the immunostimulatory effect of dietary NT is mediated by direct action of NT and does not involve the microbiota. Consistently, dietary NT can protect germ-free zebrafish from pathogenic infection, whereas germ-free zebrafish colonized with NT microbiota showed no difference in disease resistance compared with control microbiota colonized counterparts. Together, these results indicated that the immunostimulatory and disease protection effect of dietary nucleotides in zebrafish was mediated by direct action of the nucleotides, and does not involve the intestinal microbiota.

In vitro exposure to 2,2',4,4'-tetrabromodiphenyl ether (PBDE-47) impairs innate inflammatory response

Polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants that are added to numerous products to prevent accidental fires. PBDEs are present in the environment and they bio-accumulate in human and animal tissues. Recently, their presence has been correlated to several pathologies but little is known about their effect on the human innate immune system activity. In this study we investigated the effect of the congener 2,2',4,4'-Tetrabromodiphenyl ether (PBDE-47) on the functional activity of the THP-1 human macrophages cell line and on ex vivo freshly isolated human basophils. Cytotoxicity and genotoxicity studies showed that PBDE-47 was able to induce toxic effects on the THP-1 cell line viability at concentrations ≥25 μM. Immune function of THP-1 was studied after stimulation with bacterial lipopolysaccharide (LPS) and PBDE-47 exposure at concentrations granting macrophage viability. Two dimensional electrophoresis showed modification of the proteome in the 3 μM PBDE-47 treated sample and Real Time PCR and ELISA demonstrated a statistically significant reduction in the expression of IL-1β, IL-6 and TNF-α cytokines. Furthermore, PBDE-47 was able to perturbate genes involved in cell motility upregulating CDH-1 and downregulating MMP-12 expressions. Finally, basophil activation assay showed reduced CD63 activation in PBDE-47 treated samples. In conclusion, our study demonstrated that PBDE-47 may perturb the activities of cells involved in innate immunity dampening the expression of macrophage pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and genes involved in cell motility (MMP-12 and E-cadherin) and interfering with basophil activation suggesting that this compound can impair innate immune response.

Coevolution pays off: Herpesviruses have the license to escape the DNA sensing pathway

Early detection of viral invasion by pattern recognition receptors (PRR) is crucial for the induction of a rapid and efficient immune response. Cytosolic DNA sensors are the most recently described class of PRR, and induce transcription of type I interferons (IFN) and proinflammatory cytokines via the key adaptor protein stimulator of interferon genes (STING). Herpesviruses are a family of large DNA viruses widely known for their immense arsenal of proteins dedicated to manipulating and evading host immune responses. Tantamount to the significant role played by DNA sensors and STING in innate immune responses, herpesviruses have in turn evolved a range of mechanisms targeting virtually every step of this key signaling pathway. Strikingly, some herpesviruses also take advantage of this pathway to promote their own replication. In this review, we will summarize the current understanding of DNA sensing and subsequent induction of signaling and transcription, and showcase the close adaptation of herpesviruses to their host reflected by the myriad of viral proteins dedicated to modulating this critical innate immune pathway.

Proteolytic cleavage of host proteins by the Group IV viral proteases of Venezuelan equine encephalitis virus and Zika virus

The alphaviral nonstructural protein 2 (nsP2) cysteine proteases (EC 3.4.22.-) are essential for the proteolytic processing of the nonstructural (ns) polyprotein and are validated drug targets. A common secondary role of these proteases is to antagonize the effects of interferon (IFN). After delineating the cleavage site motif of the Venezuelan equine encephalitis virus (VEEV) nsP2 cysteine protease, we searched the human genome to identify host protein substrates. Here we identify a new host substrate of the VEEV nsP2 protease, human TRIM14, a component of the mitochondrial antiviral-signaling protein (MAVS) signalosome. Short stretches of homologous host-pathogen protein sequences (SSHHPS) are present in the nonstructural polyprotein and TRIM14. A 25-residue cyan-yellow fluorescent protein TRIM14 substrate was cleaved in vitro by the VEEV nsP2 protease and the cleavage site was confirmed by tandem mass spectrometry. A TRIM14 cleavage product also was found in VEEV-infected cell lysates. At least ten other Group IV (+)ssRNA viral proteases have been shown to cleave host proteins involved in generating the innate immune responses against viruses, suggesting that the integration of these short host protein sequences into the viral protease cleavage sites may represent an embedded mechanism of IFN antagonism. This interference mechanism shows several parallels with those of CRISPR/Cas9 and RNAi/RISC, but with a protease recognizing a protein sequence common to both the host and pathogen. The short host sequences embedded within the viral genome appear to be analogous to the short phage sequences found in a host's CRISPR spacer sequences. To test this algorithm, we applied it to another Group IV virus, Zika virus (ZIKV), and identified cleavage sites within human SFRP1 (secreted frizzled related protein 1), a retinal G_s alpha subunit, NT5M, and Forkhead box protein G1 (FOXG1) in vitro. Proteolytic cleavage of these proteins suggests a possible link between the protease and the virus-induced phenotype of ZIKV. The algorithm may have value for selecting cell lines and animal models that recapitulate virus-induced phenotypes, predicting host-range and susceptibility, selecting oncolytic viruses, identifying biomarkers, and de-risking live virus vaccines. Inhibitors of the proteases that utilize this mechanism may both inhibit viral replication and alleviate suppression of the innate immune responses.

Mitochondria: the indispensable players in innate immunity and guardians of the inflammatory response

Mitochondria, the dynamic organelles and power house of eukaryotic cells function as metabolic hubs of cells undergoing continuous cycles of fusion and fission. Recent findings have made it increasingly apparent that mitochondria essentially involved in energy production have evolved as principal intracellular signaling platforms regulating not only innate immunity but also inflammatory responses. Perturbations in mitochondrial dynamics, including fusion/fission, electron transport chain (ETC) architecture and cristae organization have now been actively correlated to modulate metabolic activity and immune function of innate and adaptive immune cells. Several newly identified mitochondrial proteins in mitochondrial outer membrane such as mitochondrial antiviral signaling protein (MAVS) and with mitochondrial DNA acting as danger-associated molecular pattern (DAMP) and mitochondrial ROS generated from mitochondrial sources have potentially established mitochondria as key signaling platforms in antiviral immunity in vertebrates and thereby orchestrating adaptive immune cell activations respectively. A thorough understanding of emerging and intervening role of mitochondria in toll-like receptor-mediated innate immune responses and NLRP3 inflammasome complex activation has gained lucidity in recent years that advocates the imposing functions of mitochondria in innate immunity. Fascinatingly, also how the signals stemming from the endoplasmic reticulum co-operate with the mitochondria to activate the NLRP3 inflammasome is now looked ahead as a stage to unravel as to how different mitochondrial and associated organelle stress responses co-operate to bring about inflammatory consequences. This has also opened avenues of research for revealing mitochondrial targets that could be exploited for development of novel therapeutics to treat various infectious, inflammatory, and autoimmune disorders. Thus, this review explores our current understanding of intricate interplay between mitochondria and other cellular processes like autophagy in controlling mitochondrial homeostasis and regulation of innate immunity and inflammatory responses.

High-resolution quantitative proteomics applied to the study of the specific protein signature in the sputum and saliva of active tuberculosis patients and their infected and uninfected contacts

Our goal was to establish panels of protein biomarkers that are characteristic of patients with microbiologically confirmed pulmonary tuberculosis (TB) and their contacts, including latent TB-infected (LTBI) and uninfected patients. Since the first pathogen-host contact occurs in the oral and nasal passages the saliva and sputum were chosen as the biological fluids to be studied. Quantitative shotgun proteomics was performed using a LTQ-Orbitrap-Elite platform. For active TB patients, both fluids exhibited a specific accumulation of proteins that were related to complement activation, inflammation and modulation of immune response. In the saliva of TB patients, a decrease of in proteins related to glucose and lipid metabolism was detected. In contrast, the sputum of uninfected contacts presented a specific proteomic signature that was composed of proteins involved in the perception of bitter taste, defense against pathogens and innate immune response, suggesting that those are key events during the initial entry of the pathogen in the host. SIGNIFICANCE: This is the first study to compare the saliva and sputum from active TB patients and their contacts. Our findings strongly suggest that TB patients show not only an activation of processes that are related to complement activation and modulation of inflammation but also an imbalance in carbohydrate and lipid metabolism. In addition, those individuals who do not get infected after direct exposure to the pathogen display a typical proteomic signature in the sputum, which is a reflection of the secretion from the nasal and oral mucosa, the first immunological barriers that M. tuberculosis encounters in the host. Thus, this result indicates the importance of the processes related to the innate immune response in fighting the initial events of the infection.

Establishment and characterization of an immortalized renal cell line of the Chinese tree shrew (Tupaia belangeri chinesis)

The Chinese tree shrew holds a great potential as a viable animal model in biomedical research, especially for infectious diseases and neuropsychiatric disorders. A thorough understanding of the innate immunity, which represents the first line that defends the host against viral infection, of the Chinese tree shrew, is needed. However, the progress is hindered by the lack of a proper cell line for research usage. In this study, we established a cell line that is applicable to the study of tree shrew innate immune responses against viral infections. The Chinese tree shrew primary renal cells (TSPRCs) were immortalized by simian virus 40 large T antigen (SV40LT) transduction, and the immortalized cells were termed TSR6 (tree shrew renal cell #6). TSR6 showed a similar morphology to TSPRCs and expressed the epithelial cell-specific marker cytokeratin 18 (KRT18). In addition, TSR6 could be transfected by transfection reagent and was suitable for CRISPR/Cas9-mediated gene editing. Infection of Newcastle disease virus (NDV) or herpes simplex virus 1 (HSV-1) in TSR6 induced the mRNA expression of tree shrew interferon-β (tIFNB1) and myxovirus resistance protein 1 (tMx1) in a dose- and time-dependent manner. Collectively, we successfully established a tree shrew renal cell line and demonstrated that this cell line was suitable for the study of the innate immune response to viral infections.

Development of a new method for collecting hemolymph and measuring phenoloxidase activity in Tribolium castaneum

Objective

Hemolymph plays many important roles in the physiology of an insect throughout its lifetime; however, for small-bodied insects, studies are lacking because of the difficulties encountered while collecting hemolymph. The objective of our study was to develop a method to collect hemolymph plasma from various stages of Tribolium castaneum and to evaluate phenoloxidase activity in the plasma samples. We first designed a procedure for easily and quickly collecting clear hemolymph plasma from T. castaneum.

Results

By using this method, we collected approximately 5 µl plasma from 30 individuals at the larval, pupal or adult stages. And then, we studied the expression of phenoloxidase by performing western blot analysis of the plasma samples and found that phenoloxidase is present in hemolymph in each developmental stage. We also measured phenoloxidase activity in control plasma and plasma treated with Gram-positive bacteria, Micrococcus luteus. Phenoloxidase activity was greater in some of the M. luteus-treated plasma samples compared with control samples. Thus, we developed a method to collect hemolymph plasma that is suitable for studies of phenoloxidase activity.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-4041-y) contains supplementary material, which is available to authorized users.

Haptoglobin improves acute phase response and endotoxin tolerance in response to bacterial LPS

Sepsis is characterized by delayed acute phase response and lowered immune tolerance in patients. Acute phase serum proteins, like Haptoglobin (Hp), have been associated with increased mortality in bacteria mediated acute lung inflammation and sepsis in neonates. However, it's direct role in modulating the immune response by regulating pro-inflammatory mediators leading to immune tolerant state and if gender affects its expression levels during bacterial infection, especially in blood has not been fully explored. To understand its specific role in endotoxin-mediated immune response, we investigated the correlation between the rise in Hp levels on bacterial infection and its influence on the expression of pro-inflammatory mediators in male and female Whole blood (WHB) and PBMCs. Here, we observed pathogen-specific and gender-specific expression of Hp. Gonadal steroid hormones differentially influenced the Hp expression in LPS-induced WHB, where the addition of Estrogen increased Hp expression, with suppression of TNFα, in both genders. Further on evaluating, the influence of Hp on TNFα expression in endotoxin tolerance (ET), we show that increased Hp levels directly reduced TNFα expression in ET models. Interestingly, blockade of secreted Hp significantly reversed the (ET) state, confirmed by a significant rise in TNFα expression in both ex vivo and in vitro ET models, indicating a possible feedback inhibition by Hp on inflammatory mediators like TNFα. We also investigated the role of PKCδ in the regulation of LPS induced secretion of acute phase proteins (Hp) in serum, where inhibition of PKCδ, reduced secretion of anti-microbial proteins in response to LPS shown by restored bacterial growth. These findings clearly highlight the crucial role of Hp in maintaining immune tolerance via suppressing the pro-inflammatory mediators and also in preventing bacterial proliferation in blood during infection.

Phenylalanine enhances innate immune response to clear ceftazidime-resistant Vibrio alginolyticus in Danio rerio

Antibiotic-resistant bacteria becomes a major threat to the economy and food safety in aquaculture. Although the antibiotic-dependent strategy is still the mostly adopted option, the development of antibiotic-free approach is urgently needed to ameliorate the severe situation of the global antibiotic resistance. In the present study, we showed that modulating the metabolism of zebrafish, Danio reiro, would enhance D. rerio to clear ceftazidime-resistant Vibrio alginoyticus (Caz-R) in vivo. By generating Caz-R in vitro, we found Caz-R stays longer than ceftazidime-sensitive V. alginoyticus (Caz-S) in D. rerio, where Caz-R induced less potent immune response than that of Caz-S. The differential immune response was associated with different metabolism of the host. Through functional metabolomics, we identified a crucial biomarker, phenylalanine. The abundance of phenylalanine was increased in both of Caz-S and Caz-R infected hosts but the abundance was higher in Caz-S infected group. This specific difference indicated phenylalanine could be a metabolite required to clear Caz-R by the host. Exogenous phenylalanine would enhance the host's ability to remove Caz-R, which was through upregulated production of lysozyme and C3b. Thus, our study demonstrates a novel strategy to boost host's immune response to combat against antibiotic-resistant bacteria.

Identification and functional characterization of three myeloid differentiation factor 88 (MyD88) isoforms from thick shell mussel Mytilus coruscus

Myeloid differentiation factor 88 (MyD88) is a pivotal adapter protein that involved in interleukin-1 receptor/toll-like receptor (IL-1R/TLR) signal transduction, which could spur downstream cascades and eventually drawn into innate immune response. MyD88 has been extensively studied in vertebrates, however, the information ascribe to MyD88 in invertebrates is still very scarce especially its function annotation remains extremely obscure. At here, three novel MyD88 isoforms termed McMyD88a, McMyD88b and McMyD88c were firstly cloned from thick shell mussel Mytilus coruscus. McMyD88a, McMyD88b and McMyD88c shared domain topology containing the Death domain (DD) and TIR domain (TIR) with its counterparts in mammals. All three McMyD88s were ubiquitously expressed in examined tissues in thick shell mussel, with the higher expression levels in immune-related tissues such as haemocytes, gills and digestive glands. Upon Vibrio alginolyticus, polyinosine-polycytidylic acid (poly I:C) and lipopolysaccharide (LPS) challenge, McMyD88a, McMyD88b and McMyD88c transcripts were significantly induced in haemocytes despite of differential expression levels and responsive time points. Overexpression of McMyD88a, McMyD88b and McMyD88c showed a dose-dependent induction to NF-κB or ISRE in mammalian cell lines. Taken together, these results suggested that McMyD88a, McMyD88b and McMyD88c are members of MyD88 family and play potential roles in innate immune response to pathogenic invasions in thick shell mussel. Moreover, these results suggested indirectly the existence of a MyD88-dependent signaling pathway in thick shell mussel, and provide insight into the immunoregulatory effect in molluscs.

Impact of neuroimmune activation induced by alcohol or drug abuse on adolescent brain development

Evidence obtained in recent decades has demonstrated that the brain still matures in adolescence. Changes in neural connectivity occur in different regions, including cortical and subcortical structures, which undergo modifications in white and gray matter densities. These alterations concomitantly occur in some neurotransmitter systems and hormone secretion, which markedly influence the refinement of certain brain areas and neural circuits. The immaturity of the adolescent brain makes it more vulnerable to the effects of alcohol and drug abuse, whose use can trigger long-term behavioral dysfunction. This article reviews the action of alcohol and drug abuse (cannabis, cocaine, opioids, amphetamines, anabolic androgenic steroids) in the adolescent brain, and their impact on both cognition and behavioral dysfunction, including predisposition to drug abuse in later life. It also discusses recent evidence that indicates the role of the neuroimmune system response and neuroinflammation as mechanisms that participate in many actions of ethanol and drug abuse in adolescence, including the neurotoxicity and alterations in neurocircuitry that contribute to the dysfunctional behaviors associated with addiction. The new data suggest the therapeutic potential of anti-inflammatory targets to prevent the long-term consequences of drug abuse in adolescence.

Age-related deregulation of TDP-43 after stroke enhances NF-κB-mediated inflammation and neuronal damage

Background

TDP-43 has been identified as a disease-associated protein in several chronic neurodegenerative disorders and increasing evidence suggests its potentially pathogenic role following brain injuries. Normally expressed in nucleus, under pathological conditions TDP-43 forms cytoplasmic ubiquitinated inclusions in which it is abnormally phosphorylated and cleaved to generate a 35 and a 25 kDa C-terminal fragments. In the present study, we investigated age-related expression patterns of TDP-43 in neurons and glia and its role as modulator of inflammation following ischemic injury.

Methods

Wild-type and TDP-43 transgenic mice of different age groups were subjected to transient middle cerebral artery occlusion. The role of TDP-43 in modulation of inflammation was assessed using immunofluorescence, Western blot analysis, and in vivo bioluminescence imaging. Finally, post-mortem stroke human brain sections were analyzed for TDP-43 protein by immunohistochemistry.

Results

We report here an age-related increase and formation of ubiquitinated TDP-43 cytoplasmic inclusions after stroke. The observed deregulation in TDP-43 expression patterns was associated with an increase in microglial activation and innate immune signaling as revealed by in vivo bioluminescence imaging and immunofluorescence analysis. The presence of ubiquitinated TDP-43 aggregates and its cleaved TDP-35 and TDP-25 fragments was markedly increased in older, 12-month-old mice leading to larger infarctions and a significant increase in in neuronal death. Importantly, unlike the hallmark neuropathological features associated with chronic neurodegenerative disorders, the TDP-43-positive cytoplasmic inclusions detected after stroke were not phosphorylated. Next, we showed that an increase and/or overexpression of the cytoplasmic TDP-43 drives the pathogenic NF-κB response and further increases levels of pro-inflammatory markers and ischemic injury after stroke in age-dependent manner. Finally, analyses of the post-mortem stroke brain tissues revealed the presence of the cytoplasmic TDP-43 immunoreactive structures after human stroke.

Conclusion

Together, our findings suggest that the level of cytoplasmic TDP-43 increases with aging and may act as an age-related mediator of inflammation and neuronal injury after stroke. Thus, targeting cytoplasmic TDP-43 may have a therapeutic potential after stroke.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1350-y) contains supplementary material, which is available to authorized users.

Applying microarray-based technique to study and analyze silkworm (Bombyx mori) transcriptomic response to long-term high iron diet

To investigate the biological processes affected by long-term iron supplementation, newly hatched silkworms were exposed to high iron mulberry diet (10 and 100 ppm) and its effect on silkworm transcriptom was determined. The results showed that the silkworm was responsive to iron by increasing iron concentration and ferritin levels in the hemolymph and by regulating the expression of many other genes. A total of 523 and 326 differentially expressed genes were identified in 10 and 100 ppm Fe group compared to the control, respectively. Of these genes, 249 were shared between in both the 10 ppm and 100 ppm Fe group, including 152 up-regulated and 97 down-regulated genes. These shared genes included 19 known Fe regulated, 24 immune-related, 12 serine proteases and serine proteases homologs, 41 cuticular and cuticle genes. Ten genes (carboxypeptidases A, serine protease homologs 85, fibrohexamerin/P25, transferrin, sex-specific storage-protein 2, fungal protease inhibitor F, insect intestinal mucin, peptidoglycan recognition protein B, cuticle protein CPH45, unknown gene) were involved in the regulation of iron overload responses.

Immunometabolic Effect of Cholesterol in Hepatitis C Infection: Implications in Clinical Management and Antiviral Therapy

Hepatitis C virus (HCV) is a lipid-enveloped virion particle that causes infection to the liver, and as part of its life cycle, it disrupts the host lipid metabolic machinery, particularly the cholesterol synthesis pathway. The innate immune response generated by liver resident immune cells is responsible for successful viral eradication. Unfortunately, most patients fail to eliminate HCV and progress to chronic infection. Chronic infection is associated with hepatic fat accumulation and inflammation that triggers fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Despite that the current direct-acting antiviral agents have increased the cure rate of HCV infection, viral genotype and the host genetic background influence both the immune response and lipid metabolism. In this context, recent evidence has shown that cholesterol and its derivatives such as oxysterols might modulate and potentialize the hepatic innate immune response generated against HCV. The impairment of the HCV life cycle modulated by serum cholesterol could be relevant for the clinical management of HCV-infected patients before and after treatment. Alongside, cholesterol levels are modulated either by genetic variations in IL28B, ApoE, and LDLR or by dietary components. Indeed, some nutrients such as unsaturated fatty acids have demonstrated to be effective against HCV replication. Thus, cholesterol modifications may be considered as a new adjuvant strategy for HCV infection therapy by providing a biochemical tool that guides treatment decisions, an improved treatment response and favoring viral clearance. Herein, the mechanisms by which cholesterol contributes to the immune response against HCV infection and how genetic and environmental factors may affect this role are reviewed.