Molecular mechanisms of emerging inflammasome complexes and their activation and signaling in inflammation and pyroptosis.

Inflammasomes are multi-protein complexes that assemble within the cytoplasm of mammalian cells in response to pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs), driving the secretion of the pro-inflammatory cytokines IL-1ß and IL-18, and pyroptosis. The best-characterized inflammasome complexes are the NLRP3, NAIP-NLRC4, NLRP1, AIM2, and Pyrin canonical caspase-1-containing inflammasomes, and the caspase-11 non-canonical inflammasome. Newer inflammasome sensor proteins have been identified, including NLRP6, NLRP7, NLRP9, NLRP10, NLRP11, NLRP12, CARD8, and MxA. These inflammasome sensors can sense PAMPs from bacteria, viruses and protozoa, or DAMPs in the form of mitochondrial damage, ROS, stress and heme. The mechanisms of action, physiological relevance, consequences in human diseases, and avenues for therapeutic intervention for these novel inflammasomes are beginning to be realized. Here, we discuss these emerging inflammasome complexes and their putative activation mechanisms, molecular and signaling pathways, and physiological roles in health and disease.

The Science of Cholesteatoma.

Cholesteatoma is a potential end-stage outcome of chronic ear infections that can result in the destruction of temporal bone structures with potential resultant hearing loss, vertigo, and intracranial infectious complications. There is currently no treatment apart from surgery for this condition, and despite years of study, the histopathogenesis of this disease remains poorly understood. This review is intended to summarize our accumulated knowledge of the mechanisms of cholesteatoma development and the underlying molecular biology. Attention will be directed particularly to recent developments, covering many potential pharmacologic targets that could be used to treat this disease in the future.

Enhanced Accumulation of Health-Promoting Cajaninstilbene Acid in Pigeon Pea Hairy Root Cultures Cocultured with an Endophytic Fungus during Early Stages of Colonization.

Endophytic fungi can effectively regulate the biosynthesis of health-beneficial metabolites in plants. However, few studies have revealed how the accumulation of host metabolites varies during interactions with endophytic fungi. Here, pigeon pea hairy root cultures (PPHRCs) were cocultured with an endophytic fungus Penicillium rubens to explore the impact on the biosynthesis and accumulation of cajaninstilbene acid (CSA). The results showed that CSA accumulation in PPHRCs increased significantly (15.29-fold) during the early stages of P. rubens colonization (fungal attachment and invasion phases). Once P. rubens successfully colonized the intercellular gap of hairy roots to form a symbiotic relationship, the CSA levels in PPHRCs decreased drastically. Moreover, P. rubens could be recognized by plant pattern recognition receptors that regulate immunity/symbiosis, triggering the expression of genes related to pathogenesis, CSA biosynthesis, and ABC transporter. Overall, P. rubens could enhance the accumulation of health-promoting CSA in PPHRCs during the early stages of colonization.

The role of pattern recognition receptors in the innate immune system of Chinese mitten crab (Eriocheir sinensis).

Eriocheir sinensis (Chinese mitten crab) is one of the main economic species in China, which has evolved an extremely sophisticated innate immune system to fend off disease invasions. However, bacterial and viral infections have caused significant financial losses for the E. sinensis aquaculture in recent years. Making well-informed judgments for the control microbial infections would require a thorough understanding and clarification of the intricate innate immune system of E. sinensis. Innate immunity is essential for the host's defense against invasive pathogens. Pattern recognition receptors (PRRs) initially recognize pathogen-associated molecular patterns (PAMPs) and trigger an innate immune response, causing the generation of inflammatory cytokine and promoting the clearance and control of pathogens. In E. sinensis, Toll/Toll-like receptors, lipopolysaccharide and ß-1,3-glucan binding proteins, C-type lectins, galactoside-binding lectins, L-type lectins, scavenger receptors, and down syndrome cell adhesion molecules have been identified to be PRRs that are involved in the recognition of bacteria, fungi, and viruses. In this review, we give a comprehensive overview of the literature regarding PRRs' roles in the immunological defenses of E. sinensis, with the aim of providing clues to the mechanisms of innate immunity.

Effects of dietary Lactobacillus postbiotics and bacitracin on the modulation of mucosa-associated microbiota and pattern recognition receptors affecting immunocompetence of jejunal mucosa in pigs challenged with enterotoxigenic F18+ Escherichia coli.

BACKGROUND: Enterotoxigenic Escherichia coli (E. coli) is a threat to humans and animals that causes intestinal disorders. Antimicrobial resistance has urged alternatives, including Lactobacillus postbiotics, to mitigate the effects of enterotoxigenic E. coli. METHODS: Forty-eight newly weaned pigs were allotted to NC: no challenge/no supplement; PC: F18+ E. coli challenge/no supplement; ATB: F18+ E. coli challenge/bacitracin; and LPB: F18+ E. coli challenge/postbiotics and fed diets for 28 d. On d 7, pigs were orally inoculated with F18+ E. coli. At d 28, the mucosa-associated microbiota, immune and oxidative stress status, intestinal morphology, the gene expression of pattern recognition receptors (PRR), and intestinal barrier function were measured. Data were analyzed using the MIXED procedure in SAS 9.4. RESULTS: PC increased (P < 0.05) Helicobacter mastomyrinus whereas reduced (P < 0.05) Prevotella copri and P. stercorea compared to NC. The LPB increased (P < 0.05) P. stercorea and Dialister succinatiphilus compared with PC. The ATB increased (P < 0.05) Propionibacterium acnes, Corynebacterium glutamicum, and Sphingomonas pseudosanguinis compared to PC. The PC tended to reduce (P = 0.054) PGLYRP4 and increased (P < 0.05) TLR4, CD14, MDA, and crypt cell proliferation compared with NC. The ATB reduced (P < 0.05) NOD1 compared with PC. The LPB increased (P < 0.05) PGLYRP4, and interferon-γ and reduced (P < 0.05) NOD1 compared with PC. The ATB and LPB reduced (P < 0.05) TNF-α and MDA compared with PC. CONCLUSIONS: The F18+ E. coli challenge compromised intestinal health. Bacitracin increased beneficial bacteria showing a trend towards increasing the intestinal barrier function, possibly by reducing the expression of PRR genes. Lactobacillus postbiotics enhanced the immunocompetence of nursery pigs by increasing the expression of interferon-γ and PGLYRP4, and by reducing TLR4, NOD1, and CD14.

Polymorphisms in the genes encoding RLR and TLR3 and CMV DNAemia in subjects coinfected with human immunodeficiency virus and cytomegalovirus.

Cytomegalovirus (CMV) is a pathogen that is common worldwide and is often present in individuals infected with human immunodeficiency virus (HIV). Pattern recognition receptors (PRRs) are host sensors that activate the immune response against infectious agents. However, it is unclear whether PRR single-nucleotide polymorphisms (SNPs) are associated with the occurrence of CMV DNAemia in subjects coinfected with HIV and CMV. HIV/CMV-coinfected patients with and without CMV DNAemia were recruited for this study. The DDX58 rs10813831 and IFIH1 (rs3747517 and rs1990760) polymorphisms were genotyped using the TaqMan Allelic Discrimination Assay, whereas the DDX58 rs12006123 and TLR3 (rs3775291 and rs3775296) SNPs were analyzed using a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assay. A mutation present in at least one allele of the DDX58 rs12006123 SNP occurred at least two times more frequently in HIV/CMV-coinfected patients with CMV DNAemia than in coinfected subjects without CMV DNAemia (OR, 2.50; 95% CI, 1.33-4.68; p = 0.004, in the dominant model). A higher level of CMV DNAemia was observed in subjects who had the heterozygous (GA) or homozygous recessive (AA) genotype for the DDX58 rs12006123 SNP compared with those who had the wild-type (GG) genotype (p = 0.0003). Moreover, in subjects with a mutation detected in at least one allele of the DDX58 rs12006123 SNP, a lower serum IFN-ß concentration was found compared with those who had a wild-type (GG) genotype for this polymorphism (p = 0.024). The DDX58 rs12006123 SNP is associated with CMV DNAemia in HIV/CMV-coinfected patients.

Hepatocyte-specific RIG-I loss attenuates metabolic dysfunction-associated steatotic liver disease in mice via changes in mitochondrial respiration and metabolite profiles.

Pattern recognition receptor (PRR)-mediated inflammation is an important determinant of the initiation and progression of metabolic diseases such as metabolic dysfunction-associated steatotic liver disease (MASLD). In this study, we investigated whether RIG-I is involved in hepatic metabolic reprogramming in a high-fat diet (HFD)-induced MASLD model in hepatocyte-specific RIG-I-KO (RIG-I∆hep) mice. Our study revealed that hepatic deficiency of RIG-I improved HFD-induced metabolic imbalances, including glucose impairment and insulin resistance. Hepatic steatosis and liver triglyceride levels were reduced in RIG-I-deficient hepatocytes in HFD-induced MASLD mice, and this was accompanied by the reduced expression of lipogenesis genes, such as PPARγ, Dga2, and Pck1. Hepatic RIG-I deficiency alters whole-body metabolic rates in the HFD-induced MASLD model; there is higher energy consumption in RIG-I∆hep mice. Deletion of RIG-I activated glycolysis and tricarboxylic acid (TCA) cycle-related metabolites in hepatocytes from both HFD-induced MASLD mice and methionine-choline-deficient diet (MCD)-fed mice. RIG-I deficiency enhanced AMPK activation and mitochondrial function in hepatocytes from HFD-induced MASLD mice. These findings indicate that deletion of RIG-I can activate cellular metabolism in hepatocytes by switching on both glycolysis and mitochondrial respiration, resulting in metabolic changes induced by a HFD and stimulation of mitochondrial activity. In summary, RIG-I may be a key regulator of cellular metabolism that influences the development of metabolic diseases such as MASLD. Supplementary Information: The online version contains supplementary material available at 10.1007/s43188-024-00264-x.

Toll-like Receptors: Therapeutic Potential in Life Threatening Diseases-Cardiac Disorders.

Toll-like receptors (TLRs) belong to the innate immune system. TLRs identify and respond to invading pathogens by recognizing certain molecular patterns associated with the infections. TLRs are crucial for the host's defence against these diseases. TLRs are capable of detecting several endogenous chemicals through the recognition of damage-associated molecular patterns, which are generated in response to various harmful situations. Recent animal studies have shown that TLR signaling has a significant role in the development of serious heart diseases, such as ischemia myocardial damage, myocarditis, and septic cardiomyopathy, where inflammation of the heart muscle is a key factor. This manuscript examines the animal research findings on (1) TLRs, TLR ligands, and the signal transduction system, and (2) the significant involvement of TLR signaling in these crucial cardiac diseases.

The adjuvant BcfA activates antigen presenting cells through TLR4 and supports TFH and TH1 while attenuating TH2 gene programming.

Introduction: Adjuvants added to subunit vaccines augment antigen-specific immune responses. One mechanism of adjuvant action is activation of pattern recognition receptors (PRRs) on innate immune cells. Bordetella colonization factor A (BcfA); an outer membrane protein with adjuvant function, activates TH1/TH17-polarized immune responses to protein antigens from Bordetella pertussis and SARS CoV-2. Unlike other adjuvants, BcfA does not elicit a TH2 response. Methods: To understand the mechanism of BcfA-driven TH1/TH17 vs. TH2 activation, we screened PRRs to identify pathways activated by BcfA. We then tested the role of this receptor in the BcfA-mediated activation of bone marrow-derived dendritic cells (BMDCs) using mice with germline deletion of TLR4 to quantify upregulation of costimulatory molecule expression and cytokine production in vitro and in vivo. Activity was also tested on human PBMCs. Results: PRR screening showed that BcfA activates antigen presenting cells through murine TLR4. BcfA-treated WT BMDCs upregulated expression of the costimulatory molecules CD40, CD80, and CD86 and produced IL-6, IL-12/23 p40, and TNF-α while TLR4 KO BMDCs were not activated. Furthermore, human PBMCs stimulated with BcfA produced IL-6. BcfA-stimulated murine BMDCs also exhibited increased uptake of the antigen DQ-OVA, supporting a role for BcfA in improving antigen presentation to T cells. BcfA further activated APCs in murine lungs. Using an in vitro TH cell polarization system, we found that BcfA-stimulated BMDC supernatant supported TFH and TH1 while suppressing TH2 gene programming. Conclusions: Overall, these data provide mechanistic understanding of how this novel adjuvant activates immune responses.

Plant Pattern recognition receptors: Exploring their evolution, diversification, and spatiotemporal regulation.

Plant genomes possess hundreds of candidate surface localized receptors capable of recognizing microbial components or modified-self molecules. Surface-localized pattern recognition receptors (PRRs) can recognize proteins, peptides, or structural microbial components as nonself, triggering complex signaling pathways leading to defense. PRRs possess diverse extracellular domains capable of recognizing epitopes, lipids, glycans and polysaccharides. Recent work highlights advances in our understanding of the diversity and evolution of PRRs recognizing pathogen components. We also discuss PRR functional diversification, pathogen strategies to evade detection, and the role of tissue and age-related resistance for effective plant defense.

The RNA-binding proteins regulate innate antiviral immune signaling by modulating pattern recognition receptors.

Viral infections pose significant threats to human health, leading to a diverse spectrum of infectious diseases. The innate immune system serves as the primary barrier against viruses and bacteria in the early stages of infection. A rapid and forceful antiviral innate immune response is triggered by distinguishing between self-nucleic acids and viral nucleic acids. RNA-binding proteins (RBPs) are a diverse group of proteins which contain specific structural motifs or domains for binding RNA molecules. In the last decade, numerous of studies have outlined that RBPs influence viral replication via diverse mechanisms, directly recognizing viral nucleic acids and modulating the activity of pattern recognition receptors (PRRs). In this review, we summarize the functions of RBPs in regulation of host-virus interplay by controlling the activation of PRRs, such as RIG-I, MDA5, cGAS and TLR3. RBPs are instrumental in facilitating the identification of viral RNA or DNA, as well as viral structural proteins within the cellular cytoplasm and nucleus, functioning as co-receptor elements. On the other hand, RBPs are capable of orchestrating the activation of PRRs and facilitating the transmission of antiviral signals to downstream adaptor proteins by post-translational modifications or aggregation. Gaining a deeper comprehension of the interaction between the host and viruses is crucial for the development of novel therapeutics targeting viral infections.

Structural and Phylogenetic In Silico Characterization of Vitis vinifera PRR Protein as Potential Target for Plasmopara viticola Infection.

Fungi infection, especially derived from Plasmopara viticola, causes severe grapevine economic losses worldwide. Despite the availability of chemical treatments, looking for eco-friendly ways to control Vitis vinifera infection is gaining much more attention. When a plant is infected, multiple disease-control molecular mechanisms are activated. PRRs (Pattern Recognition Receptors) and particularly RLKs (receptor-like kinases) take part in the first barrier of the immune system, and, as a consequence, the kinase signaling cascade is activated, resulting in an immune response. In this context, discovering new lectin-RLK (LecRLK) membrane-bounded proteins has emerged as a promising strategy. The genome-wide localization of potential LecRLKs involved in disease defense was reported in two grapevine varieties of great economic impact: Chardonnay and Pinot Noir. A total of 23 potential amino acid sequences were identified, exhibiting high-sequence homology and evolution related to tandem events. Based on the domain architecture, a carbohydrate specificity ligand assay was conducted with docking, revealing two sequences as candidates for specific Vitis vinifera-Plasmopara viticola host-pathogen interaction. This study confers a starting point for designing new effective antifungal treatments directed at LecRLK targets in Vitis vinifera.

An arms race between 5'ppp-RNA virus and its alternative recognition receptor MDA5 in RIG-I-lost teleost fish.

The incessant arms race between viruses and hosts has led to numerous evolutionary innovations that shape life's evolution. During this process, the interactions between viral receptors and viruses have garnered significant interest since viral receptors are cell surface proteins exploited by viruses to initiate infection. Our study sheds light on the arms race between the MDA5 receptor and 5'ppp-RNA virus in a lower vertebrate fish, Miichthys miiuy. Firstly, the frequent and independent loss events of RIG-I in vertebrates prompted us to search for alternative immune substitutes, with homology-dependent genetic compensation response (HDGCR) being the main pathway. Our further analysis suggested that MDA5 of M. miiuy and Gallus gallus, the homolog of RIG-I, can replace RIG-I in recognizing 5'ppp-RNA virus, which may lead to redundancy of RIG-I and loss from the species genome during evolution. Secondly, as an adversarial strategy, 5'ppp-RNA SCRV can utilize the m6A methylation mechanism to degrade MDA5 and weaken its antiviral immune ability, thus promoting its own replication and immune evasion. In summary, our study provides a snapshot into the interaction and coevolution between vertebrate and virus, offering valuable perspectives on the ecological and evolutionary factors that contribute to the diversity of the immune system.

Before the immune system can eliminate a bacterium, virus or other type of pathogen, it needs to be able to recognize these foreign elements. To achieve this, cells in the immune system have proteins called pattern recognition receptors (PRRs) which can identify distinct molecular features of certain pathogens. One specific group of PRRs is a family of retinoic acid-induced RIG-I-like receptors (RLRs), which help immune cells detect different types of viruses. Members of this family recognize distinct motifs on the genetic material of viruses known as RNA. For instance, RIG-I recognizes a marker known as 5'ppp on the end of single-stranded RNA molecules, whereas MDA5 recognizes long strands of double-stranded RNA. Many vertebrates ­ including various mammals, birds, and fish ­ lost the RIG-I receptor over the course of evolution. However, Geng et al. predicted that some animals lacking the RIG-I receptor may still be able to activate an immune response against viruses that contain the 5'ppp-RNA motif. To investigate this possibility, Geng et al. studied chickens and miiuy croakers (a type of ray-finned fish) which no longer have a RIG-I receptor. They found that both animals can still sense and eliminate two 5'ppp-RNA viruses called VSV and SCRV. Further experiments revealed that these two viruses are detected by a modified MDA5 receptor that had evolved to bind to 5'-ppp and activate the antiviral response. Viruses are also continuously evolving new ways to escape the immune system. This led Geng et al. to investigate whether SCRV, which causes serious harm to marine fish, has evolved a way to evade the MDA5 protection mechanism. Using miiuy croakers as a model, they found that SCRV causes the transcripts that produce the MDA5 protein to contain more molecules of m6a. This molecular tag degrades the transcript, leading to lower levels of MDA5, reducing the antiviral response against SCRV. The findings of Geng et al. offer valuable perspectives on how the immune system adapts over the course of evolution, and highlight the diversity of antiviral responses in vertebrates. Chickens and miiuy croakers are commonly farmed animals, and further work investigating how viruses invade these species could prevent illnesses from spreading and having a negative impact on the economy.

Comparative genomic analysis of copepod humoral immunity genes with sex-biased expression in Labidocera rotunda.

Studies of innate immune system function in invertebrates have contributed significantly to our understanding of the mammalian innate immune system. However, in-depth research on innate immunity in marine invertebrates remains sparse. We generated the first de novo genome and transcriptome sequences of copepod Labidocera rotunda using Illumina paired-end data and conducted a comparative genome analysis including five crustaceans (four copepods and one branchiopod species). We cataloged the presence of Toll, Imd, JAK/STAT, and JNK pathway components among them and compared them with 17 previously reported diverse arthropod species representative of insects, myriapods, chelicerates, and malacostracans. Our results indicated that copepod Gram-negative binding proteins may function in direct digestion or pathogen killing. The phylogenetic analysis of arthropod TEP and copepod-specific GCGEQ motif patterns suggested that the evolutionary history of copepod TEPs may have diverged from that of other arthropods. We classified the copepod Toll-like receptors identified in our analysis as either vertebrate or protostome types based on their cysteine motifs and the tree built with their Toll/interleukin-1 receptor domains. LrotCrustin, the first copepod AMP, was identified based on the structure of its WAP domain and deep-learning AMP predictors. Gene expression level analysis of L. rotunda innate immunity-related transcripts in each sex showed higher Toll pathway-related expression in male L. rotunda than in females, which may reflect an inverse correlation between allocation of reproductive investment and elevated immune response in males. Taken together, the results of our study provide insight into copepod innate immunity-related gene families and illuminate the evolutionary potential of copepods relative to other crustaceans.

Unravelling mechanisms of bacterial recognition by Acanthamoeba: insights into microbial ecology and immune responses.

Acanthamoeba, are ubiquitous eukaryotic microorganisms, that play a pivotal role in recognizing and engulfing various microbes during predation, offering insights into microbial dynamics and immune responses. An intriguing observation lies in the apparent preference of Acanthamoeba for Gram-negative over Gram-positive bacteria, suggesting potential differences in the recognition and response mechanisms to bacterial prey. Here, we comprehensively review pattern recognition receptors (PRRs) and microbe associated molecular patterns (MAMPs) that influence Acanthamoeba interactions with bacteria. We analyze the molecular mechanisms underlying these interactions, and the key finding of this review is that Acanthamoeba exhibits an affinity for bacterial cell surface appendages that are decorated with carbohydrates. Notably, this parallels warm-blooded immune cells, underscoring a conserved evolutionary strategy in microbial recognition. This review aims to serve as a foundation for exploring PRRs and MAMPs. These insights enhance our understanding of ecological and evolutionary dynamics in microbial interactions and shed light on fundamental principles governing immune responses. Leveraging Acanthamoeba as a model organism, provides a bridge between ecological interactions and immunology, offering valuable perspectives for future research.

Microglia and Systemic Immunity.

Microglia are specialized immune cells that reside in the central nervous system (CNS) and play a crucial role in maintaining the homeostasis of the brain microenvironment. While traditionally regarded as a part of the innate immune system, recent research has highlighted their role in adaptive immunity. The CNS is no longer considered an immune-privileged organ, and increasing evidence suggests bidirectional communication between the immune system and the CNS. Microglia are sensitive to systemic immune signals and can respond to systemic inflammation by producing various inflammatory cytokines and chemokines. This response is mediated by activating pattern recognition receptors (PRRs), which recognize pathogen- and danger-associated molecular patterns in the systemic circulation. The microglial response to systemic inflammation has been implicated in several neurological conditions, including depression, anxiety, and cognitive impairment. Understanding the complex interplay between microglia and systemic immunity is crucial for developing therapeutic interventions to modulate immune responses in the CNS.

Screening and Characterization of Immunobiotic Lactic Acid Bacteria with Porcine Immunoassay Systems.

Microorganisms with the ability to modulate the immune system (immunobiotics) have shown to interact with different pattern recognition receptors (PRRs) expressed in nonimmune and immune cells and exert beneficial effects on host's health maintenance and promotion. Suitable assay systems are necessary for an efficient and rapid screening of potential immunobiotic strains. More than a decade of research has allowed us to develop efficient in vitro models based on porcine receptors and cells (porcine immunoassay systems) to study the immunomodulatory effects of lactic acid bacteria (LAB). In addition, detailed studies of model immunobiotic LAB strains with proved abilities to improve immune health in humans (Lactobacillus rhamnosus CRL1505) or pigs (Lactobacillus jensenii TL2937) allowed us to select the most suitable biomarkers that have to be evaluated in those porcine immunoassay systems. Our in vitro models, utilizing transfectant cells expressing PRRs along with an established porcine intestinal epitheliocyte (PIE) cell line, have proven to be valuable tools for immunobiotic selection and for gaining insights into the molecular mechanisms responsible for their beneficial effects.

Dual transcriptomic analysis reveals early induced Castanea defense-related genes and Phytophthora cinnamomi effectors.

Phytophthora cinnamomi Rands devastates forest species worldwide, causing significant ecological and economic impacts. The European chestnut (Castanea sativa) is susceptible to this hemibiotrophic oomycete, whereas the Asian chestnuts (Castanea crenata and Castanea mollissima) are resistant and have been successfully used as resistance donors in breeding programs. The molecular mechanisms underlying the different disease outcomes among chestnut species are a key foundation for developing science-based control strategies. However, these are still poorly understood. Dual RNA sequencing was performed in C. sativa and C. crenata roots inoculated with P. cinnamomi. The studied time points represent the pathogen's hemibiotrophic lifestyle previously described at the cellular level. Phytophthora cinnamomi expressed several genes related to pathogenicity in both chestnut species, such as cell wall-degrading enzymes, host nutrient uptake transporters, and effectors. However, the expression of effectors related to the modulation of host programmed cell death (elicitins and NLPs) and sporulation-related genes was higher in the susceptible chestnut. After pathogen inoculation, 1,556 and 488 genes were differentially expressed by C. crenata and C. sativa, respectively. The most significant transcriptional changes occur at 2 h after inoculation (hai) in C. sativa and 48 hai in C. crenata. Nevertheless, C. crenata induced more defense-related genes, indicating that the resistant response to P. cinnamomi is controlled by multiple loci, including several pattern recognition receptors, genes involved in the phenylpropanoid, salicylic acid and ethylene/jasmonic acid pathways, and antifungal genes. Importantly, these results validate previously observed cellular responses for C. crenata. Collectively, this study provides a comprehensive time-resolved description of the chestnut-P. cinnamomi dynamic, revealing new insights into susceptible and resistant host responses and important pathogen strategies involved in disease development.

Molecular and functional in vivo characterisation of murine Dectin-1 isoforms.

Dectin-1 is a C-type lectin-receptor involved in sensing fungi by innate immune cells. Encoded by the Clec7a gene, Dectin-1 exists in two major splice isoforms, Dectin-1a and 1b, which differ in the presence of a membrane-proximal stalk domain. As reported previously, this domain determines degradative routes for Dectin-1a and 1b leading to the generation of a stable N-terminal fragment exclusively from Dectin-1a. Here, we narrow down the responsible part of the stalk and demonstrate the stabilisation of the Dectin-1a N-terminal fragment in tetraspanin-enriched microdomains. C57BL/6 and BALB/c mice show divergent Dectin-1 isoform expression patterns, which are caused by a single nucleotide polymorphism in exon 3 of the Clec7a gene, leading to a non-sense Dectin-1a mRNA in C57BL/6 mice. Using backcrossing, we generated mice with the C57BL/6 Clec7a allele on a BALB/c background and compared these to the parental strains. Expression of the C57BL/6 allele leads to the exclusive presence of the Dectin-1b protein. Furthermore, it was associated with higher Dectin-1 mRNA expression, but less Dectin-1 at the cell surface according to flow cytometry. In neutrophils, this altered ROS production induced by Dectin-1 model ligands, while cellular responses in macrophages and dendritic cells were not significantly influenced by the Dectin-1 isoform pattern.

The Molecular Signature Related to Local Inflammatory and Immune Response in Canine Cutaneous Hypersensitivity Reactions: A Preliminary Study.

Cutaneous hypersensitivity reactions (CHRs) are complex inflammatory skin disorders that affect humans and dogs. This study examined the inflammatory and immune responses leading to skin damage, inflammation, and irritation by investigating gene expression through quantitative PCR (qPCR) and protein localization through the immunohistochemistry (IHC) of specific receptors and molecules involved in CHRs. Formalin-fixed paraffin-embedded (FFPE) samples from canine CHR skin (n = 20) and healthy dog skin (n = 3) were analyzed for expression levels of eight genes, including members of the pattern recognition receptor (PRR) family, CD209 and CLEC4G, the Regakine-1-like chemokine, and acute phase proteins (APPs), LBP-like and Hp-like genes. Additionally, we examined the local involvement of IL-6, Janus Kinase 1 (JAK1), and the signal transducer activator of transcription 3 (STAT3) in the CHR cases. The study demonstrated statistically significant increases in the expression levels of CD209, Hp-like (p < 0.01), LBP-like, Regakine-1-like, and CLEC4G (p < 0.05) genes in CHRs compared to healthy controls. Conversely, IL-6, JAK1, and STAT3 showed no significant difference between the two groups (p > 0.05). Protein analysis revealed JAK1 and STAT3 expression in CHR hyperplastic epithelial cells, dermal fibroblasts, and endothelial cells of small capillaries, indicating a possible involvement in the JAK/STAT pathway in local inflammatory response regulation. Our findings suggest that the skin plays a role in the development of CHRs.