Regulation Of Innate Immunity Research Articles

Helicase protein DDX11 as a novel antiviral factor promoting RIG-I-MAVS-mediated signaling pathway.

Innate immunity is the first and most rapid host defense against virus infection. Recognition of viral RNA by the retinoic acid-inducible gene 1 (RIG-I)-like receptors (RLRs) initiates innate antiviral immune responses. How the binding of viral RNA to and activation of the RLRs are regulated remains enigmatic. In this study, we identified DEAD/H-box helicase 11 (DDX11) as a positive regulator of the RIG-I-mitochondrial antiviral signaling protein (MAVS)-mediated signaling pathways. Mechanistically, we demonstrated that DDX11 bound to viral RNA, interacted with RIG-I, and promoted their binding to viral RNA. DDX11 also promoted the interaction between RIG-I and MAVS and activation of RIG-I-MAVS signaling. Overall, our results elucidate the role of DDX11 in RIG-I-MAVS-dependent signaling pathways and may shed light on innate immune gene regulation.

Cyclooxygenase-2/prostaglandin E2 pathway orchestrates the replication of infectious bronchitis virus in chicken tracheal explants

ABSTRACT In this study, we investigated the localized pathogenesis of infectious bronchitis virus (IBV) in chicken tracheal organ cultures (TOCs), focusing on the role of inducible cyclooxygenase (COX-2). Two divergent IBV strains, respiratory Connecticut (Conn) A5968 and nephropathogenic Delmarva (DMV)/1639, were studied at 6, 12, 24, and 48 hours post-infection (hpi). Various treatments including exogenous prostaglandin (PGE)2, a selective COX-2 antagonist (SC-236), and inhibitors of PGE2 receptors and Janus kinase (JAK) were administered. IBV genome load and antigen expression were quantified using real-time quantitative PCR and immunohistochemistry. COX-2, interferon (IFN)-α, IFN-β, interleukin (IL)−1β, IL-6, and inducible nitric oxide synthase (iNOS) expressions were measured, along with PGE2 and COX-2 concentrations. IBV genome load and protein expression peaked at 12 and 24 hpi, respectively. Conn A5968-infected TOCs exhibited continuous COX-2 expression for up to 24 hpi, extended PGE2 production up to 48 hpi, and reduced inflammatory cytokine expression. In contrast, DMV/1639-infected TOCs displayed heightened inflammatory cytokine expression, brief COX-2 expression, and PGE2 production. Treatment with IFN-γ, SC-236, PGE2 receptor inhibitors, or JAK inhibitors reduced IBV infection and lesion scores, whereas exogenous PGE2 or IFN-γ pretreatment with a JAK-2 inhibitor augmented infection. These findings shed light on the innate immune regulation of IBV infection in the trachea, highlighting the involvement of the COX-2/PGE2 pathway. IMPORTANCE Understanding the localized pathogenesis of infectious bronchitis virus (IBV) within the trachea of chickens is crucial for developing effective control strategies against this prevalent poultry pathogen. This study sheds light on the role of inducible cyclooxygenase (COX-2) and prostaglandin (PGE)2 in IBV pathogenesis using chicken tracheal organ culture (TOC) models. The findings reveal distinct patterns of COX-2 expression, PGE2 production, and immune responses associated with different IBV strains, highlighting the complexity of host-virus interactions. Furthermore, the identification of specific inhibitors targeting the COX-2/PGE2 pathway and Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway provides potential therapeutic avenues for mitigating IBV infection in poultry. Overall, this study contributes to our understanding of the innate immune regulation of IBV infection within the trachea, laying the groundwork for the development of targeted interventions to control IBV outbreaks in poultry populations.

Footprints of innate immune activity during HIV-1 reservoir cell evolution in early-treated infection.

Antiretroviral treatment (ART) initiation during the early stages of HIV-1 infection is associated with a higher probability of maintaining drug-free viral control during subsequent treatment interruptions, for reasons that remain unclear. Using samples from a randomized-controlled human clinical trial evaluating therapeutic HIV-1 vaccines, we here show that early ART commencement is frequently associated with accelerated and efficient selection of genome-intact HIV-1 proviruses in repressive chromatin locations during the first year after treatment initiation. This selection process was unaffected by vaccine-induced HIV-1-specific T cell responses. Single-cell proteogenomic profiling demonstrated that cells harboring intact HIV-1 displayed a discrete phenotypic signature of immune selection by innate immune responses, characterized by a slight but significant upregulation of HLA-C, HLA-G, the IL-10 receptor, and other markers involved in innate immune regulation. Together, these results suggest an accelerated immune selection of viral reservoir cells during early-treated HIV-1 infection that seems at least partially driven by innate immune responses.

Gut microbiome-derived metabolites in Alzheimer's disease: Regulation of immunity and potential for therapeutics.

Alzheimer's disease (AD) is the most common neurodegenerative disorder and cause of dementia. Despite the prevalence of AD, there is a lack of effective disease modifying therapies. Recent evidence indicates that the gut microbiome (GMB) may play a role in AD through its regulation of innate and adaptive immunity. Gut microbes regulate physiology through their production of metabolites and byproducts. Microbial metabolites may be beneficial or detrimental to the pathogenesis and progression of inflammatory diseases. A better understanding of the role GMB-derived metabolites play in AD may lead to the development of therapeutic strategies for AD. In this review, we summarize the function of bioactive GMB-derived metabolites and byproducts and their roles in AD models. We also call for more focus on this area in the gut-brain axis field in order to create effective therapies for AD.

Systemic Innate Immune System Restoration as a Therapeutic Approach for Neurodegenerative Disease: Effects of NP001 on Amyotrophic Lateral Sclerosis (ALS) Progression.

Amyotrophic lateral sclerosis (ALS) is a diagnosis that incorporates a heterogeneous set of neurodegenerative processes into a single progressive and uniformly fatal disease making the development of a uniformly applicable therapeutic difficult. Recent multinational ALS natural history incidence studies have identified systemic chronic activation of the innate immune system as a major risk factor for developing ALS. Persistent immune activation in patients with ALS leads to loss of muscle and lowering of serum creatinine. The goal of the current study was to test whether the slowing of nerve and muscle destruction in NP001-treated ALS patients compared with controls in phase 2 studies would lead to extension of survival. Phase 2 clinical studies with NP001, an intravenously administered form of the innate immune system regulator NaClO2, are now reporting long-term survival benefits for drug recipients vs. placebo controls after only six months of intermittent treatment. As a prodrug, NP001 is converted by macrophages to taurine chloramine, a long-lived regulator of inflammation. We performed a pooled analysis of all patients who had completed the studies in two six-month NP001 phase 2 trials. Changes in respiratory vital capacity and the muscle mass product, creatinine, defined treated patients who, compared to placebo, had up to a year of extended survival. The observed longer survival in ALS patients with the greatest inflammation-associated muscle loss provides further evidence that ALS is a disease of ongoing innate immune dysfunction and that NP001 is a disease-modifying drug with sustained clinical activity.

Coronavirus M protein promotes mitophagy over virophagy by recruiting PDPK1 to phosphorylate SQSTM1 at T138

Autophagy plays a dual role in coronavirus infection, facilitating the elimination of either proviral components (virophagy) or antiviral factors such as mitochondria (mitophagy), leading to complex mechanisms of immune evasion. Understanding the mechanisms that govern the switch between the autophagic degradation of deleterious or beneficial substrates in coronavirus infection is crucial for developing precise drug targets to treat virus-induced diseases. However, this switch remains largely unknown. Using a dual split-fluorescence assay, we identify PDPK1 as a negative regulator of innate immunity, directing the transition from virophagy to mitophagy through the phosphorylation of SQSTM1 at T138. Remarkably, a PDPK1-targeting peptide inhibits the replication of various RNA viruses by restoring innate immunity through enhanced virophagy and suppressed mitophagy, thereby protecting female mice from lethal infections. These findings underscore the detrimental role of PDPK1 in innate immunity by orchestrating the shift from virophagy to mitophagy, positioning PDPK1 as a promising pharmacological target for effectively combating a broad spectrum of virus infections.

The Versatile Role of Peroxisome Proliferator-Activated Receptors in Immune-Mediated Intestinal Diseases.

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that sense lipophilic molecules and act as transcription factors to regulate target genes. PPARs have been implicated in the regulation of innate immunity, glucose and lipid metabolism, cell proliferation, wound healing, and fibrotic processes. Some synthetic PPAR ligands are promising molecules for the treatment of inflammatory and fibrotic processes in immune-mediated intestinal diseases. Some of these are currently undergoing or have previously undergone clinical trials. Dietary PPAR ligands and changes in microbiota composition could modulate PPARs' activation to reduce inflammatory responses in these immune-mediated diseases, based on animal models and clinical trials. This narrative review aims to summarize the role of PPARs in immune-mediated bowel diseases and their potential therapeutic use.

Innate immune regulation in inflammation resolution and liver regeneration in drug-induced liver injury.

Drug-induced liver injury (DILI) is an acute liver injury that poses a significant threat to human health. In severe cases, it can progress into chronic DILI or even lead to liver failure. DILI is typically caused by either intrinsic hepatotoxicity or idiosyncratic metabolic or immune responses. In addition to the direct damage drugs inflict on hepatocytes, the immune responses and liver inflammation triggered by hepatocyte death can further exacerbate DILI. Initially, we briefly discussed the differences in immune cell activation based on the type of liver cell death (hepatocytes, cholangiocytes, and LSECs). We then focused on the role of various immune cells (including macrophages, monocytes, neutrophils, dendritic cells, liver sinusoidal endothelial cells, eosinophils, natural killer cells, and natural killer T cells) in both the liver injury and liver regeneration stages of DILI. This article primarily reviews the role of innate immune regulation mediated by these immune cells in resolving inflammation and promoting liver regeneration during DILI, as well as therapeutic approaches targeting these immune cells for the treatment of DILI. Finally, we discussed the activation and function of liver progenitor cells (LPCs) during APAP-induced massive hepatic necrosis and the involvement of chronic inflammation in DILI.

AXIN1 boosts antiviral response through IRF3 stabilization and induced phase separation

Axis inhibition protein 1 (AXIN1), a scaffold protein interacting with various critical molecules, plays a vital role in determining cell fate. However, its impact on the antiviral innate immune response remains largely unknown. Here, we identify that AXIN1 acts as an effective regulator of antiviral innate immunity against both DNA and RNA virus infections. In the resting state, AXIN1 maintains the stability of the transcription factor interferon regulatory factor 3 (IRF3) by preventing p62-mediated autophagic degradation of IRF3. This is achieved by recruiting ubiquitin-specific peptidase 35 (USP35), which removes lysine (K) 48-linked ubiquitination at IRF3 K366. Upon virus infection, AXIN1 undergoes a phase separation triggered by phosphorylated TANK-binding kinase 1 (TBK1). This leads to increased phosphorylation of IRF3 and a boost in IFN-I production. Moreover, KYA1797K, a small molecule that binds to the AXIN1 RGS domain, enhances the AXIN1-IRF3 interaction and promotes the elimination of various highly pathogenic viruses. Clinically, patients with HBV-associated hepatocellular carcinoma (HCC) who show reduced AXIN1 expression in pericarcinoma tissues have low overall and disease-free survival rates, as well as higher HBV levels in their blood. Overall, our findings reveal how AXIN1 regulates IRF3 signaling and phase separation-mediated antiviral immune responses, underscoring the potential of the AXIN1 agonist KYA1797K as an effective antiviral agent.

Pityriasis rubra pilaris: A review

Pityriasis rubra pilaris (PRP, syn.: Devergie's disease) is a rare idiopathic papulo-squamous inflammatory skin disease characterized by follicular papules, palmar-plantar keratoderma, scaling plaques of orange-red color with characteristic foci of unaffected skin. Histologically, the alternating pattern of orthokeratosis and parakeratosis is considered a distinctive feature of PRP (staggered hyperkeratosis). A violation of the regulation of innate immunity is a component of the pathogenesis of PRP. Congenital mutations of CARD 14 or concomitant antigens, which can take the form of iatrogenic lesions, infections or malignant neoplasms, can be the initial triggers of the disease, although the etiology is often idiopathic. There are classically five subtypes of the disease, depending on the age of onset and clinical picture. Type VI PRP is associated with infection caused by the human immunodeficiency virus. CARD 14-associated papulosquamous rash and discoid dermatitis of the face represent new clinical phenotypes of PRP. Devergie's disease has a pronounced negative impact on the quality of life, and those who become ill are at increased risk of depression and suicide. Ixekizumab, methotrexate and secukinumab can be considered as systemic drugs of the first choice. If there is a contraindication to immunosuppressive therapy, high doses of isotretinoin are recommended. Topical agents, including calcipotriene, calcineurin inhibitors, emollients and topical corticosteroids, are used as additional therapy.

TIPE2 aggravates experimental colitis and disrupts intestinal epithelial barrier integrity by activating JAK2/STAT3/SOCS3 signal pathway

Ulcerative colitis (UC) is a chronic relapsing and progressive inflammatory disease of the colon. TIPE2 is a negative regulator of innate and adaptive immunity that maintains immune homeostasis. We found that TIPE2 was highly expressed in mucosa of mice with colitis. However, the role of TIPE2 in colitis remains unclear. We induced colitis in mice with dextran sulphate sodium (DSS) and treated them with TIPE2, and investigated the inflammatory activity of the colon in vivo by cytokines detection and histopathological analyses. We also measured inflammatory alteration and tight junctions induced by DSS in vitro. The results demonstrated that administration of TIPE2 promoted the severity of colitis in mice and human colon epithelial cells. Furthermore, TIPE2 aggravated intestinal epithelial barrier dysfunction by decreasing the expression of the tight junction proteins Occludin, Claudin-1 and ZO-1. In addition, TIPE2 exacerbated intestinal inflammatory response by inhibiting the expression of SOCS3, remarkably activating JAK2/STAT3 signaling pathway, and increasing the translocation of phosphorylated STAT3 into the nucleus. Silencing of Tipe2 attenuated the DSS-induced activation of JAK2/STAT3, thereby rescuing epithelial inflammatory injury and restoring barrier dysfunction. These results indicate that TIPE2 augments experimental colitis and disrupted the integrity of the intestinal epithelial barrier by activating the JAK2/STAT3/SOCS3 signaling pathway.

Transcriptional regulation of hormone signalling genes in black pepper in response to Phytophthora capsici

IntroductionBlack pepper (Piper nigrum L.) is a non-model spice crop of significant agricultural and biological importance. The ‘quick wilt’ disease caused by the oomycete Phytophthora capsici is a major threat, leading to substantial crop loss. The molecular mechanisms governing the plant immune responses to this pathogen remain unclear. This study employs RNA sequencing and transcriptome analysis to explore the defense mechanisms of P. nigrum against P. capsici.ResultsTwo-month-old P. nigrum plantlets were subjected to infection with P. capsici, and leaf samples were collected at 6- and 12-hours post-inoculation. RNA was extracted, sequenced, and the resulting data were processed and assembled. Differential gene expression analysis was conducted to identify genes responding to the infection. Additionally, the study investigated the involvement of Salicylic acid (SA), Jasmonic acid (JA), and Ethylene (ET) signalling pathways. Our transcriptome assembly comprised 64,667 transcripts with 96.7% completeness, providing valuable insights into the P. nigrum transcriptome. Annotation of these transcripts identified functional categories and domains, provided details on molecular processes. Gene expression analysis identified 4,714 transcripts at 6 h post-infection (hpi) and 9,416 at 12 hpi as differentially expressed, revealing dynamic regulation of immune-related genes. Furthermore, the study investigated key genes involved in biosynthesis pathways of Salicylic acid, Jasmonic acid, and Ethylene signalling. Notably, we found differential regulation of critical genes associated with these pathways while comparing data before and after infection, thereby shedding light on their roles in defense mechanism in P. nigrum defense.ConclusionsThis comprehensive transcriptome analysis of P. nigrum response to P. capsici attack provides valuable insights into the plant defense mechanisms. The dynamic regulation of innate immunity and the involvement of key signalling pathways highlight the complexity of the plant-pathogen interaction. This study contributes to our understanding of plant immunity and offers potential strategies for enhancing P. nigrum resistance to this harmful pathogen.

Abstract C122: Androgen receptor-mediated regulation of innate immunity in prostate cancer in Black men

Abstract Black men are two times more likely to die from prostate cancer (PCa) than White men. We reported that innate immune cell infiltration varies between races, and others have reported differences in androgen receptor (AR) expression by race or ancestry. Herein, we evaluated AR status and immune cell infiltration in primary and metastatic PCa tissues obtained from Black and White men. RNA in situ hybridization (RISH) AR analysis was done on a tissue microarray (TMA) constructed from radical prostatectomy tissues from 120 Black men matched to 60 White men on age, grade and stage. RISH or immunohistochemistry (IHC) analysis of AR, NKX3.1, prostate specific antigen (PSA), mast cells (tryptase), neutrophils (CD66), and macrophages (CD206, CD68, CD80) was done on a TMA containing rapid autopsy tissues from metastatic sites (n=11) collected from Black (n=5) and White (n=16) men. Multiplexing IHC (mIHC) was used to assess AR, neutrophils (CD66ce), mast cells (tryptase), T-cells (CD4, CD8), and M2 macrophages (CD163) on radical prostatectomy whole-tissue sections obtained at Johns Hopkins Medicine, Baltimore, MD and biopsy tissues obtained from the University of Nairobi, Nairobi, Kenya. Tumor regions on TMAs were annotated by a pathologist and signal intensity per unit area measured using TMAJ and FrIDA software. HALO Image Analysis Platform (version 3.6.4134.137; Indica Labs) was used to analyze mIHC stained tissues. Statistical analysis and graphing were done using GraphPad Prism. There was increased AR mRNA expression in primary cancer tissues from Black men compared to White men (p<0.0001) after negative binomial regression with the adjustment of TMA set, age, grade and stage. There was a negative correlation between AR expression and CD66+ neutrophils in tumor and benign tissues from Black men (R = -0.318;p = 0.002) but this correlation was not significant among White men (R= -0.045; p = 0.765). Interestingly, we measured a positive correlation between AR mRNA expression and tryptase+ mast cells among White men (R= 0.320; p=0.016), but a trend toward a negative relationship among Black men (R= -0.252;p = 0.075) We also measured a positive correlation between AR and CD163+(R= 0.324; p<0.001), CD68+(R= 0.514;p<0.001), and CD80+(R= 0.386;p<0.001) macrophages in primary tumor tissues from all men. NKX3.1 and PSA protein were significantly increased in metastatic tissues from White compared to Black men. Conversely, CD68+ and CD80+ macrophages were increased in Black compared to White men. CD66+ neutrophils and CD206+ macrophages were increased in AR- compared to AR intact metastatic tissues. Immune cells appeared to be primarily void of AR expression in primary cancer tissues by mIHC, but there was a subset CD4+ and CD8+ T-cell clusters that express AR. Immune cell infiltration varies by the presence of AR in both primary and metastatic PCa tissues. We observed differences in AR mRNA and AR-related proteins between Black and White patients which may contribute to the differences observed in immune cell infiltration between the two races Citation Format: Kennedy Rains, Katie M. Farkouh, Taylor N. Godwin, Eric Erak, Aakash Parikh, Michael Considine, Elana Fertig, Jiayun Lu, Charles Waihenya, Valerie Odero-Marah, Karen S. Sfanos, Angelo M. De Marzo, Corinne E. Joshu, Janielle P. Maynard. Androgen receptor-mediated regulation of innate immunity in prostate cancer in Black men [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C122.

The Molecular Toll Pathway Repertoire in Anopheline Mosquitoes.

Innate immunity in mosquitoes has received much attention due to its potential impact on vector competence for vector-borne disease pathogens, including malaria parasites. The nuclear factor (NF)-κB-dependent Toll pathway is a major regulator of innate immunity in insects. In mosquitoes, this pathway controls transcription of the majority of the known canonical humoral immune effectors, mediates anti-bacterial, anti-fungal and anti-viral immune responses, and contributes to malaria parasite killing. However, besides initial gene annotation of putative Toll pathway members and genetic analysis of the contribution of few key components to immunity, the molecular make-up and function of the Toll pathway in mosquitoes is largely unexplored. To facilitate functional analyses of the Toll pathway in mosquitoes, we report here manually annotated and refined gene models of Toll-like receptors and all putative components of the intracellular signal transduction cascade across 19 anopheline genomes, and in two culicine genomes. In addition, based on phylogenetic analyses, we identified differing levels of evolutionary constraint across the intracellular Toll pathway members, and identified a recent radiation of TOLL1/5 within the An. gambiae complex. Together, this study provides insight into the evolution of TLRs and the putative members of the intracellular signal transduction cascade within the genus Anopheles.

Non-Coding RNAs in Myasthenia Gravis: From Immune Regulation to Personalized Medicine.

Myasthenia gravis (MG) is an antibody-mediated autoimmune disorder characterized by altered neuromuscular transmission, which causes weakness and fatigability in the skeletal muscles. The etiology of MG is complex, being associated with multiple genetic and environmental factors. Over recent years, progress has been made in understanding the immunological alterations implicated in the disease, but the exact pathogenesis still needs to be elucidated. A pathogenic interplay between innate immunity and autoimmunity contributes to the intra-thymic MG development. Epigenetic changes are critically involved in both innate and adaptive immune response regulation. They can act as (i) pathological factors besides genetic predisposition and (ii) co-factors contributing to disease phenotypes or patient-specific disease course/outcomes. This article reviews the role of non-coding RNAs (ncRNAs) as epigenetic factors implicated in MG. Particular attention is dedicated to microRNAs (miRNAs), whose expression is altered in MG patients' thymuses and circulating blood. The long ncRNA (lncRNA) contribution to MG, although not fully characterized yet, is also discussed. By summarizing the most recent and fast-growing findings on ncRNAs in MG, we highlight the therapeutic potential of these molecules for achieving immune regulation and their value as biomarkers for the development of personalized medicine approaches to improve disease care.

TIPE2 inhibits the migration and invasion of epithelial ovarian cancer cells by targeting Smad2 to reverse TGF-β1-induced EMT.

Epithelial ovarian cancer is the deadliest gynecologic malignancy, characterized by high metastasis. Transforming growth factor-β1 (TGF-β1) drives epithelial- mesenchymal transformation (EMT), a key process in tumor metastasis. Tumor necrosis factor-α-induced protein 8 (TNFAIP8)-like 2 (TIPE2) acts as a negative regulator of innate and adaptive immunity and involves in various cancers. However, its relationship with TGF-β1 in ovarian cancer and its role in reversing TGF-β1-induced EMT remain unclear. This study examined TIPE2 mRNA and protein expression using quantitative RT-PCR (qRT-PCR), western blot and immunohistochemistry. The effects of TIPE2 overexpression and knockdown on the proliferation, migration and invasion of epithelial ovarian cancer cells were assessed through 5-ethynyl-2-deoxyuridine, colony-forming, transwell migration and invasion assays. The relationship between TIPE2 and TGF-β1 was investigated using qRT-PCR and enzyme-linked immunosorbent assay, while the interaction between TIPE2 and Smad2 was identified via co-immunoprecipitation. The results revealed that TIPE2 protein was significantly down-regulated in epithelial ovarian cancer tissues and correlated with the pathological type of tumor, patients' age, tumor differentiation degree and FIGO stage. TIPE2 and TGF-β1 appeared to play an opposite role to each other during the progression of human ovarian cancer cells. Furthermore, TIPE2 inhibited the metastasis and EMT of ovarian cancer cells by combining with Smad2 invitro or in an intraperitoneal metastasis model. Consequently, these findings suggest that TIPE2 plays a crucial inhibitory role in ovarian cancer metastasis by modulating the TGF-β1/Smad2/EMT signaling pathway and may serve as a potential target for ovarian cancer, providing important direction for future diagnostic and therapeutic strategies.

The innate immune regulator MyD88 dampens fibrosis during zebrafish heart regeneration

The innate immune response is triggered rapidly after injury and its spatiotemporal dynamics are critical for regeneration; however, many questions remain about its exact role. Here we show that MyD88, a key component of the innate immune response, controls not only the inflammatory but also the fibrotic response during zebrafish cardiac regeneration. We find in cryoinjured myd88−/− ventricles a significant reduction in neutrophil and macrophage numbers and the expansion of a collagen-rich endocardial population. Further analyses reveal compromised PI3K/AKT pathway activation in the myd88−/− endocardium and increased myofibroblasts and scarring. Notably, endothelial-specific overexpression of myd88 reverses these neutrophil, fibrotic and scarring phenotypes. Mechanistically, we identify the endocardial-derived chemokine gene cxcl18b as a target of the MyD88 signaling pathway, and using loss-of-function and gain-of-function tools, we show that it controls neutrophil recruitment. Altogether, these findings shed light on the pivotal role of MyD88 in modulating inflammation and fibrosis during tissue regeneration.

Single-cell transcriptome landscape of the kidney reveals potential innate immune regulation mechanisms in hybrid yellow catfish after Aeromonas hydrophila infection

Aeromonas hydrophila, the pathogen that is the causative agent of motile Aeromonas septicemia (MAS) disease, commonly attacks freshwater fishes, including yellow catfish (Pelteobagrus fulvidraco). Although the kidney is one of the most important organs involved in immunity in fish, its role in disease progression has not been fully elucidated. Understanding the cellular composition and innate immune regulation mechanisms of the kidney of yellow catfish is important for the treatment of MAS. In this study, single-cell RNA sequencing (scRNA-seq) was performed on the kidney of hybrid yellow catfish (Pelteobagrus fulvidraco ♀ × Pelteobagrus vachelli ♂) after A. hydrophila infection. Nine types of kidney cells were identified using marker genes, and a transcription module of marker genes in the main immune cells of hybrid yellow catfish kidney tissue was constructed using in-situ hybridization. In addition, the single-cell transcriptome data showed that the differentially expressed genes of macrophages were primarily enriched in the Toll-like receptor and Nod-like receptor signaling pathways. The expression levels of genes involved in these pathways were upregulated in macrophages following A. hydrophila infection. Transmission electron microscopy and TUNEL analysis revealed the cellular characteristics of macrophages before and after A. hydrophila infection. These data provide empirical support for in-depth research on the role of the kidney in the innate immune response of hybrid yellow catfish.

Luciferase Reporter Systems in Investigating Interferon Antiviral Innate Immunity.

Luciferase reporter systems are commonly used in scientific research to investigate a variety of biological processes, including antiviral innate immunity. These systems employ the use of luciferase enzymes derived from organisms such as fireflies or renilla reniformis, which emit light upon reaction with a substrate. In the context of antiviral innate immunity, the luciferase reporter systems offer a noninvasive and highly sensitive approach for real-time monitoring of immune responses in vitro and in vivo, enabling researchers to delve into the intricate interactions and signaling pathways involved in host-virus dynamic interactions. Here, we describe the methods of the promoter-luciferase reporter and enhancer-luciferase reporter, which provide insights into the transcriptional and post-transcriptional regulation of antiviral innate immunity. Additionally, we outline the split-luciferase complementary reporter method, which was designed to explore protein-protein interactions associated with antiviral immunity. These methodologies offer invaluable knowledge regarding the molecular mechanisms underlying antiviral immune pathways and have the potential to support the development of effective antiviral therapies.

Characterization and functional analysis of chicken promyelocytic leukemia protein

In mammals, promyelocytic leukemia (PML) protein, also named as TRIM19, is the key component of nuclear membrane-less sub structures PML nuclear bodies (PML-NBs) or nuclear domains 10 (ND10). PML-NBs are dynamic foci that consist of numerous permanently or transiently associated proteins. The mammalian PMLs are involved in the regulation of various cellular pathways, including apoptosis, intrinsic and innate antiviral immunity, cell cycle, DNA damage, senescence and etc. Nevertheless, little is known about the role of chicken PML (chPML). In this study, chPML gene was cloned, and its several functions were characterized. We found that chPML was widely expressed in different tissues of chickens, and showed different subcellular distribution pattern in DF-1 cells comparing with LMH and HD11 cells. Like human PML, chPML was identified to be SUMOylated. K463 is one critical SUMOylation site and 240RARRG244 is SUMO interaction motif (SIM) of chPML. Moreover, qPCR showed that chPML could not only up-regulate the expression of host innate immune factor IFN-β and its downstream ISGs, but also antigen presentation-related factors including class II transactivator (CIITA) and MHC II DM beta 2 (DMB2). Notably, over-expression of chIFN-β could promote the expression of endogenous chPML. All these provide novel insights into the function of chPML, and pave the way for further studying the roles of chPML in biological process and anti-infection function.