MicroRNA gga-miR-200a-3p modulates immune response via MAPK signaling pathway in chicken afflicted with necrotic enteritis

Characterization of microRNA candidates at the primary site of infectious bronchitis virus infection: A comparative study of in vitro and in vivo avian models

Infectious bronchitis virus (IBV) is an important avian pathogen with a positive-sense single-stranded RNA genome. IBV is the causative agent of infectious bronchitis (IB), a primarily respiratory disease affecting chickens, with the ability to disseminate to other organ systems, such as the gastrointestinal, renal, lymphoid, and reproductive systems. Tracheal epithelial cells are the primary target of IBV, and these cells play a vital role in the effective induction of the antiviral response and eventual clearance of IBV. The host immune system is regulated by a number of different molecular players, including micro-ribonucleic acids (microRNAs), which are small, conserved, non-coding RNA molecules that regulate gene expression of complementary messenger RNA (mRNA) sequences, resulting in gene silencing through translational repression or target degradation. The goal of this study was to characterize and compare the microRNA expression profiles in chicken tracheal epithelial cells (cTECs) in vitro and the trachea in vivo upon IBV Delmarva/1639 (DMV/1639) or IBV Massachusetts 41 (Mass41) infections. We hypothesized that IBV infection influences the expression of the host microRNA expression profiles. cTECs and young specific pathogen-free (SPF) chickens were infected with IBV DMV/1639 or IBV Mass41 and the microRNA expression at 3 and 18 hours post-infection (hpi) in the cTECs and at 4 and 11 days post-infection (dpi) in the trachea were determined using small RNA-sequencing (RNA-seq). We found that the profile of differentially expressed (DE) microRNAs is largely dependent on the IBV strain and time point of sample collection. Furthermore, we predicted the interaction between host microRNA and IBV viral RNA using microRNA-RNA interaction prediction platforms. We identified several candidate microRNAs suitable for future functional studies, such as gga-miR-155, gga-miR-1388a, gga-miR-7/7b and gga-miR-21-5p. Characterizing the interaction between IBV and the host cells at the level of microRNA regulation provides further insight into the regulatory mechanisms involved in viral infection and host defense in chickens following IBV infection.

Embryonic heat conditioning induces paternal heredity of immunological cross- tolerance: coordinative role of CpG DNA methylation and miR-200a regulation

Background

Enhancing an organism's survival hinges on the development of balanced and adaptable stress response systems. While the initial stress-response set-points in the hypothalamus may be genetically determined, they are further influenced by epigenetic factors during embryonic development. A debate persists regarding the heritability of such behavioral traits. The chick in ovo heat conditioning model offers a unique insight into this fundamental question, where manipulation during embryonic development can induce heat resilience and even cross-tolerance to promote immunological resilience. In this study, we conducted an analysis of thermal manipulation during embryogenesis to demonstrate paternal heredity and investigate its transmission through sperm DNA methylation in coordination with miR-200a action.

Result

First-generation embryos underwent in ovo heat conditioning (EHC), creating a cohort of embryonic EHC and control chicks. These chicks were then subjected to an intracranial lipopolysaccharide (LPS) challenge. Conditioning rendered the chicks immune resilient, as evidenced by their fibril effect. Male offspring were raised to maturity, and their sperm was analyzed for methylome patterns, revealing significant differences between treatments, particularly in immune and development related genes. Additionally, sperm from EHC males was used for artificial insemination of naïve Cobb hens, resulting in untreated offspring that displayed immune resilience upon LPS challenge, indicating transgenerational effects. Overlap analysis of sperm methylome and differentially methylated sites (DMS) of offspring hypothalamus revealed inheritance of altered methylation associated with specific genes. Several of these genes are potential effectors of miR-200a, whose expression profile in the hypothalamus during LPS challenge was conserved across both generations. To evaluate the role of miR-200a in cross-tolerance acquisition, miR-200a was intracranially injected, and RNA-seq analysis of the hypothalamus revealed genes involved in the regulation of developmental and metabolic processes, stress, and immune response.

Conclusion

This study demonstrates paternal trait heredity by revealing that EHC induces cross-tolerance with the immunological system, rendering chicks resilient to LPS that transgenerationally transmit this to untreated offspring. Additionally, analysis of sperm methylation patterns in EHC mature chicks led to identification of genes associated with neuronal development and immune response, indicating potential neural network reorganization. Finally, miR-200a emerges as a regulator potentially involved in mediating the cross-tolerance effect.

Integrated Transcriptome Analysis Reveals the Lung miRNA-mRNA Regulatory Network Associated with Avian Pathogenic E. coli Infection

Avian pathogenic E. coli (APEC), one of the most common pathogens, can cause localized or systemic infections and lead to significant economic losses in the poultry industry annually. Recently, evidence suggests that microRNAs (miRNAs) play important roles in the host immune response to bacterial infection by targeting mRNAs. However, few studies have examined the immune mechanisms of miRNAs and mRNAs in chicken lungs following APEC infection. Herein, hematoxylin-eosin staining and qRT-PCR were employed to investigate APEC-induced lung inflammation in chickens. RNAseq was used to identify the miRNAs and mRNAs expression profile between the APEC infection group (APEC) vs. the Control group (Control). The results show that APEC can induce lung lesions in chickens and increase the expression levels of inflammatory cytokines (IL1β, IL8, IL6, and TNFα). High-quality sequencing data were obtained, of which more than 93% of the reads can be mapped to the chicken genome. A total of 22 differentially expressed (DE) miRNAs and 608 DE mRNAs were detected in the APEC vs. the Control. Remarkably, 23 regulatory pairs of miRNA-mRNA interactions were identified in chicken lungs upon APEC infection. Further validation revealed that gga-miR-214 could directly target the RAB37 gene upon APEC infection to modulate the expression of inflammatory cytokine response. This study provides new insights into the host immune response to APEC infection.

Early Biomarkers for Detecting Subclinical Exposure to Fumonisin B1, Deoxynivalenol, and Zearalenone in Broiler Chickens

Identifying biomarkers of mycotoxin effects in chickens will provide an opportunity for early intervention to reduce the impact of mycotoxicosis. This study aimed to identify whether serum enzyme concentrations, gut integrity, and liver miRNAs can be potential biomarkers for fumonisin B1 (FB1), deoxynivalenol (DON), and zearalenone (ZEA) toxicity in broiler birds as early as 14 days after exposure. A total of 720 male broiler chicks were distributed to six treatment groups: T1: control group (basal diet), T2 (2 FB1 + 2.5 DON + 0.9 ZEA), T3 (5 FB1 + 0.4 DON + 0.1 ZEA), T4 (9 FB1 + 3.5 DON + 0.7 ZEA), T5 (17 FB1 + 1.0 DON + 0.2 ZEA), and T6 (21 FB1 + 3.0 DON + 1.0 ZEA), all in mg/kg diet. On d14, there were no significant differences in the body weight gain (BWG) of mycotoxin treatment groups when compared to the control (p > 0.05), whereas on d21, T6 birds showed significantly reduced BWG compared to the control (p < 0.05). On d14, birds in T6 showed significant upregulation of liver miRNAs, gga-let-7a-5p (14.17-fold), gga-miR-9-5p (7.05-fold), gga-miR-217-5p (16.87-fold), gga-miR-133a-3p (7.41-fold), and gga-miR-215-5p (6.93-fold) (p < 0.05) and elevated serum fluorescein isothiocyanate-dextran (FITC-d) concentrations, aspartate aminotransferase (AST), and creatine kinase (CK) levels compared to the control (p < 0.05). On d21, T2 to T6 birds exhibited reduced serum phosphorus, glucose, and potassium, while total protein, FITC-d, AST, and CK levels increased compared to control (p < 0.05). These findings suggest that serum FITC-d, AST, CK, and liver miRNAs could serve as biomarkers for detecting mycotoxin exposure in broiler chickens.

Role of miRNA in Highly Pathogenic H5 Avian Influenza Virus Infection: An Emphasis on Cellular and Chicken Models

The avian influenza virus, particularly the H5N1 strain, poses a significant and ongoing threat to both human and animal health. Recent outbreaks have affected domestic and wild birds on a massive scale, raising concerns about the virus' spread to mammals. This review focuses on the critical role of microRNAs (miRNAs) in modulating pro-inflammatory signaling pathways during the pathogenesis of influenza A virus (IAV), with an emphasis on highly pathogenic avian influenza (HPAI) H5 viral infections. Current research indicates that miRNAs play a significant role in HPAI H5 infections, influencing various aspects of the disease process. This review aims to synthesize recent findings on the impact of different miRNAs on immune function, viral cytopathogenicity, and respiratory viral replication. Understanding these mechanisms is essential for developing new therapeutic strategies to combat avian influenza and mitigate its effects on both human and animal populations.

MicroRNAs: exploring their role in farm animal disease and mycotoxin challenges

MicroRNAs (miRNAs) serve as key regulators in gene expression and play a crucial role in immune responses, holding a significant promise for diagnosing and managing diseases in farm animals. This review article summarizes current research on the role of miRNAs in various farm animal diseases and mycotoxicosis, highlighting their potential as biomarkers and using them for mitigation strategies. Through an extensive literature review, we focused on the impact of miRNAs in the pathogenesis of several farm animal diseases, including viral and bacterial infections and mycotoxicosis. They regulate gene expression by inducing mRNA deadenylation, decay, or translational inhibition, significantly impacting cellular processes and protein synthesis. The research revealed specific miRNAs associated with the diseases; for instance, gga-miR-M4 is crucial in Marek's disease, and gga-miR-375 tumor-suppressing function in Avian Leukosis. In swine disease such as Porcine Respiratory and Reproductive Syndrome (PRRS) and swine influenza, miRNAs like miR-155 and miR-21-3p emerged as key regulatory factors. Additionally, our review highlighted the interaction between miRNAs and mycotoxins, suggesting miRNAs can be used as a biomarker for mycotoxin exposure. For example, alterations in miRNA expression, such as the dysregulation observed in response to Aflatoxin B1 (AFB1) in chickens, may indicate potential mechanisms for toxin-induced changes in lipid metabolism leading to liver damage. Our findings highlight miRNAs potential for early disease detection and intervention in farm animal disease management, potentially reducing significant economic losses in agriculture. With only a fraction of miRNAs functionally characterized in farm animals, this review underlines more focused research on specific miRNAs altered in distinct diseases, using advanced technologies like CRISPR-Cas9 screening, single-cell sequencing, and integrated multi-omics approaches. Identifying specific miRNA targets offers a novel pathway for early disease detection and the development of mitigation strategies against mycotoxin exposure in farm animals.

Albumen exosomes alleviate LPS-induced inflammation of intestinal epithelial cells via miR-22/ATM/p53/NF-κB axis

Biological macromolecules identified in albumen were found benefit to intestinal health, whether albumen contains exosomes and function of their cargos in intestinal inflammation remain unknown. This study aimed to investigate characteristics and cargos of albumen exosomes, as well as their potential roles in alleviating inflammation in intestinal epithelial cells. Our results demonstrated that albumen contains exosomes that are cup-shaped morphology vesicles with diameter ranging from 50 to 200 nm. There were 278 miRNAs and 45 proteins with higher expression levels in albumen exosomes, and they were mainly involved in immune responses and programmed cell death pathways, including apoptosis and p53 signaling pathway. LPS induced overexpression of pro-inflammatory cytokines IL-1β and TNF-α and excessive apoptosis, which could be reversed by albumen exosomes. The beneficial effects of exosomes could be mainly attributed to miRNA cargos and their inhibition on inflammatory response signaling pathways (p53 and NF-κB pathways). Mechanically, exosome miR-22 targeted ATM and inhibited p53/NF-κB pathway, alleviating LPS-induced overexpression of Caspase-3 and Bax, and inflammatory response. Collectively, albumen exosomes alleviate inflammation of intestinal epithelial cells via miR-22/ATM/p53/NF-κB axis and these findings may provide theoretical basis to the potential application of albumen exosomes for intestinal inflammation.

Identification of mapk genes, and their expression profiles in response to low salinity stress, in cobia (Rachycentron canadum)

Mitogen-activated protein kinases (MAPKs) are a class of protein kinases that regulate various physiological processes, and play a crucial role in maintaining the osmotic equilibrium of fish. The objective of this study was to identify and characterize the mapk family genes in cobia (Rachycentron canadum) and examine their expression profiles under different low salinity stress regimes (acute: from 30‰ to 10‰ in 1 h, sub-chronic: from 30‰ to 10‰ over 4 d). A total of 12 cobia mapk genes (Rcmapks) were identified and cloned, including six erk subfamily genes (Rcmapk1/3/4/6/7/15), three jnk subfamily genes (Rcmapk8/9/10) and three p38 mapk subfamily genes (Rcmapk 11/13/14). Domain analysis indicated that the RcMAPKs possessed the typical domains including S_TKc and PKc_like domain. Phylogenetic analysis revealed that the Rcmapks were most closely related to those of the turbot (Scophthalmus maximus). The tissue distribution of mapk genes in adult cobia and the expression patterns of Rcmapks under different low salinity stress regimes were investigated using quantitative real-time PCR (qRT-PCR). The results revealed that Rcmapk3/9/10/11/13/14 exhibited a relatively broad expression distribution across 14 different tissues. For all these genes the highest expression level was in the brain, except for Rcmapk14 (highly expressed in the stomach, gill, and skin). The genes Rcmapk1/6/15 showed significantly higher expression in the testis. Under acute low salinity stress, expression of Rcmapk1/3/6/7/9/11/13/14 was significantly altered in the gill, intestine, and trunk kidney, however, the aforementioned genes exhibited very different expression patterns among the three tissues. In the gill, most of the genes from the erk (Rcmapk3/6/7) and p38 mapk subfamily (Rcmapk11/13/14) were significantly up-regulated at almost all the time points (P < 0.05); Similarly, the expression of Rcmapk3/9/11/13/14 genes were significantly increased in the trunk kidney; while in the intestine, most of the altered genes (Rcmapk6/7/9/11/13/14) were significantly down-regulated at 1 h. Following the sub-chronic low salinity stress, expression of Rcmapk1/3/6/7/9/11/13/14 genes were significantly altered in all three tissues. These findings provide important reference data for elucidating the roles of cobia mapk family genes in response to low salinity stress.

Chicken miR-26a-5p modulates MDA5 during highly pathogenic avian influenza virus infection

MicroRNAs play crucial roles in immune-related pathways in host animals. In this study, we aimed to investigate the systemic biological function of gga-miR-26a-5p, a chicken miRNA, in the immune responses to HPAIV H5N1 infection in the Vietnamese Ri chicken line. Our results showed a significant downregulation in gga-miR-26a expression in the lung tissue of Ri chickens during HPAIV H5N1 infection. Overexpression of gga-miR-26a and the reporter construct, either containing the wildtype or mutant melanoma differentiation-associated protein 5 (MDA5) 3' untranslated region (3' UTR)-luciferase, into a chicken fibroblast cell line, revealed that gga-miR-26a can act as a direct translational repressor of MDA5 by targeting the 3' UTRs. Additionally, miR-26a negatively regulated the expression of the signaling molecules related to the MDA5 signaling pathway, including MDA5, mitochondrial antiviral-signaling (MAVS), interferon regulatory factor 7 (IRF7), p38 mitogen-activated protein kinases, and nuclear factor-kappa B (NF-κB). Moreover, downstream of the IRF7 and NF-κB signaling pathway, the proinflammatory cytokines such as IL-1β, IFN-γ, IFN-α, IFN-β, and the interferon-stimulated gene (Mx1) were, likewise, downregulated by the overexpression of gga-miR-26a. These findings suggest that gga-miR-26a-5p serves as an important regulator in the MDA5 signaling pathway and antiviral response. Overall, our results contribute to an improved understanding of the biological functions of gga-miR-26a-5p, alongside the mechanisms underlying the MDA5 signaling pathway, and the antiviral response to HPAIV-H5N1 infection in chickens.

Chicken miR-148a-3p regulates immune responses against AIV by targeting the MAPK signalling pathway and IFN-γ

MicroRNAs are involved in the immune systems of host animals and play essential roles in several immune-related pathways. In the current study, we investigated the systemic biological function of the chicken miRNA gga-miR-148a-3p on immune responses in chicken lines resistant and susceptible to HPAIV-H5N1. We found that gga-miR-148a expression in the lung tissue of H5N1-resistant chickens was significantly downregulated during HPAIV-H5N1 infection. Overexpression of gga-miR-148a and a reporter construct with wild type or mutant IFN-γ, MAPK11, and TGF-β2 3' untranslated region (3' UTR)-luciferase in chicken fibroblasts showed that gga-miR-148a acted as a direct translational repressor of IFN-γ, MAPK11, and TGF-β2 by targeting their 3' UTRs. Furthermore, miR-148a directly and negatively influenced the expression of signalling molecules related to the MAPK signalling pathway, including MAPK11, TGF-β2, and Jun, and regulated antiviral responses through interferon-stimulated genes and MHC class I and class II genes by targeting IFN-γ. Downstream of the MAPK signalling pathway, several proinflammatory cytokines such as IL-1β, IFN-γ, IL-6, TNF-α, IFN-β, and interferon-stimulated genes were downregulated by the overexpression of gga-miR-148a. Our data suggest that gga-miR-148a-3p is an important regulator of the MAPK signalling pathway and antiviral response. These findings improve our understanding of the biological functions of gga-miR-148a-3p, the mechanisms underlying the MAPK signalling pathway, and the antiviral response to HPAIV-H5N1 infection in chickens as well as the role of gga-miR-148a-3p in improving the overall performance of chicken immune responses for breeding disease-resistant chickens.

Analysis of miRNA expression in the trachea of Ri chicken infected with the highly pathogenic avian influenza H5N1 virus

BACKGROUND

Highly pathogenic avian influenza virus (HPAIV) is considered a global threat to both human health and the poultry industry. MicroRNAs (miRNA) can modulate the immune system by affecting gene expression patterns in HPAIV-infected chickens.

OBJECTIVES

To gain further insights into the role of miRNAs in immune responses against H5N1 infection, as well as the development of strategies for breeding disease-resistant chickens, we characterized miRNA expression patterns in tracheal tissues from H5N1-infected Ri chickens.

METHODS

miRNAs expression was analyzed from two H5N1-infected Ri chicken lines using small RNA sequencing. The target genes of differentially expressed (DE) miRNAs were predicted using miRDB. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis were then conducted. Furthermore, using quantitative real-time polymerase chain reaction, we validated the expression levels of DE miRNAs (miR-22-3p, miR-146b-3p, miR-27b-3p, miR-128-3p, miR-2188-5p, miR-451, miR-205a, miR-203a, miR-21-3p, and miR-200a-3p) from all comparisons and their immune-related target genes.

RESULTS

A total of 53 miRNAs were significantly expressed in the infection samples of the resistant compared to the susceptible line. Network analyses between the DE miRNAs and target genes revealed that DE miRNAs may regulate the expression of target genes involved in the transforming growth factor-beta, mitogen-activated protein kinase, and Toll-like receptor signaling pathways, all of which are related to influenza A virus progression.

CONCLUSIONS

Collectively, our results provided novel insights into the miRNA expression patterns of tracheal tissues from H5N1-infected Ri chickens. More importantly, our findings offer insights into the relationship between miRNA and immune-related target genes and the role of miRNA in HPAIV infections in chickens.

The biological functions of maternal-derived extracellular vesicles during pregnancy and lactation and its impact on offspring health

During pregnancy and lactation, mothers provide not only nutrients, but also many bioactive components for their offspring through placenta and breast milk, which are essential for offspring development. Extracellular vesicles (EVs) are nanovesicles containing a variety of biologically active molecules and participate in the intercellular communication. In the past decade, an increasing number of studies have reported that maternal-derived EVs play a crucial role in offspring growth, development, and immune system establishment. Hereby, we summarized the characteristics of EVs; biological functions of maternal-derived EVs during pregnancy, including implantation, decidualization, placentation, embryo development and birth of offspring; biological function of breast milk-derived EVs (BMEs) on infant oral and intestinal diseases, immune system, neurodevelopment, and metabolism. In summary, emerging studies have revealed that maternal-derived EVs play a pivotal role in offspring health. As such, maternal-derived EVs may be used as promising biomarkers in offspring disease diagnosis and treatment. However, existing research on maternal-derived EVs and offspring health is largely limited to animal and cellular studies. Evidence from human studies is needed.

Effect of acute Cu exposure on immune response mechanisms of golden cuttlefish (Sepia esculenta)

Sepia esculenta is a common economic cephalopod that has received extensive attention due to the tender meat, rich protein content and certain medicinal value thereof. Over the past decade, multiple industries have discharged waste into the ocean in large quantities, thereby significantly increasing the concentration of heavy metals in the ocean. Copper (Cu) is a common heavy metal in the ocean. The increase of Cu content will affect numerous biological processes such as immunity and metabolism of marine organisms. High concentrations of Cu may inhibit S. esculenta growth, development, swimming, and other processes, which would significantly affect its culture. In this research, transcriptome analysis is used to initially explore Cu-exposed S. esculenta larval immune response mechanisms. And compared to control group with normally growing larvae, 2056 differentially expressed genes (DEGs) are identified in experimental group with Cu-exposed larvae. The results of DEGs functional enrichment analyses including GO and KEGG indicate that Cu exposure might promote inflammatory and innate immune responses in cuttlefish larvae. Then, 10 key genes that might regulate larval immunity are identified using a comprehensive analysis that combines protein-protein interaction (PPI) network and KEGG functional enrichment analyses, of which three genes with the highest number of protein interactions or involve in more KEGG signaling pathways are identified as hub genes that might significantly affect larval immune response processes. Comprehensive analysis of PPI network and KEGG signaling pathway are used for the first time to explore Cu-exposed S. esculenta larval immune response mechanisms. Our results preliminarily reveal immune response mechanisms of cephalopods exposed to heavy metals and provide valuable resources for further understanding mollusk immunity.

Exploration of immune response mechanisms in cadmium and copper co-exposed juvenile golden cuttlefish (Sepia esculenta) based on transcriptome profiling

Sepia esculenta is a popular economic cephalopod with high yield, delicious meat, and rich nutrition. With the rapid development of heavy industry and medical industry, a large amount of waste has been released into the ocean recklessly in recent years, inducing a significant increase in the content of heavy metals, especially cadmium (Cd) and copper (Cu), in the ocean. This phenomenon significantly affects the growth and development of S. esculenta, causing a serious blow to its artificial breeding. In this study, transcriptome analysis is used to initially explore immune response mechanisms of Cd and Cu co-exposed juvenile S. esculenta. The results show that 1,088 differentially expressed genes (DEGs) are identified. And DEGs functional enrichment analysis results suggests that co-exposure may promote inflammatory and innate immune responses in juvenile S. esculenta. Fifteen key genes that might regulate the immunity of S. esculenta are identified using protein-protein interaction (PPI) network and KEGG enrichment analyses, of which the three genes with the highest number of interactions or involve in more KEGG pathways are identified as hub genes that might significantly affect the immune response processes. Comprehensive analysis of PPI network and KEGG signaling pathway is used for the first time to explore co-exposed S. esculenta juvenile immune response processes. Our results preliminarily reveal immune response mechanisms of cephalopods exposed to heavy metals and provide a valuable resource for further understanding of mollusk immunity.

Study of microRNA expression in Salmonella Typhimurium-infected porcine ileum reveals miR-194a-5p as an important regulator of the TLR4-mediated inflammatory response

Infection with Salmonella Typhimurium (S. Typhimurium) is a common cause of food-borne zoonosis leading to acute gastroenteritis in humans and pigs, causing economic losses to producers and farmers, and generating a food security risk. In a previous study, we demonstrated that S. Typhimurium infection produces a severe transcriptional activation of inflammatory processes in ileum. However, little is known regarding how microRNAs regulate this response during infection. Here, small RNA sequencing was used to identify 28 miRNAs differentially expressed (DE) in ileum of S. Typhimurium-infected pigs, which potentially regulate 14 target genes involved in immune system processes such as regulation of cytokine production, monocyte chemotaxis, or cellular response to interferon gamma. Using in vitro functional and gain/loss of function (mimics/CRISPR-Cas system) approaches, we show that porcine miR-194a-5p (homologous to human miR-194-5p) regulates TLR4 gene expression, an important molecule involved in pathogen virulence, recognition and activation of innate immunity in Salmonella infection.

A blend of microencapsulated organic acids and botanicals reduces necrotic enteritis via specific signaling pathways in broilers

Necrotic enteritis (NE) is a devastating disease that has seen a resurgence of cases following the removal of antibiotics from feed resulting in financial loss and significant animal health concerns across the poultry industry. The objective was to evaluate the efficacy of a microencapsulated blend of organic (25% citric and 16.7% sorbic) acids and botanicals (1.7% thymol and 1% vanillin [AviPlusP]) to reduce clinical NE and determine the signaling pathways associated with any changes. Day-of-hatch by-product broiler breeder chicks were randomly assigned to a control (0) or supplemented (500 g/MT) diet (n = 23-26) and evaluated in a NE challenge model (n = 3). Birds were administered 2X cocci vaccine on d 14 and challenged with a cocktail of Clostridium perfringens strains (107) on d 17 to 19. On d 20 to 21 birds were weighed, euthanized, and scored for NE lesions. Jejunal tissue was collected for kinome analysis using an immuno-metabolism peptide array (n = 5; 15/treatment) to compare tissue from supplement-fed birds to controls. Mortality and weight were analyzed using Student's t test and lesion scores analyzed using F-test two-sample for variances (P < 0.05). The kinome data was analyzed using PIIKA2 peptide array analysis software and fold-change between control and treated groups determined. Mortality in the supplemented group was 47.4% and 70.7% in controls (P = 0.004). Lesions scores were lower (P = 0.006) in supplemented birds (2.47) compared to controls (3.3). Supplement-fed birds tended (P = 0.19) to be heavier (848.6 g) than controls (796.2 g). Kinome analysis showed T cell receptor, TNF and NF-kB signaling pathways contributed to the improvements seen in the supplement-fed birds. The following peptides were significant (P < 0.05) in all 3 pathways: CHUK, MAP3K14, MAP3K7, and NFKB1 indicating their importance. Additionally, there were changes to IL6, IL10, and IFN- γ mRNA expression in tissue between control- and supplement-fed chickens. In conclusion, the addition of a microencapsulated blend of organic acids and botanicals to a broiler diet reduced the clinical signs of NE that was mediated by specific immune-related pathways.

MicroRNA-361-5p Aggravates Acute Pancreatitis by Promoting Interleukin-17A Secretion via Impairment of Nuclear Factor IA-Dependent Hes1 Downregulation

This study set out to explore the potential role of microRNA-361-5p (miR-361-5p) in acute pancreatitis through regulation of interleukin-17A (IL-17A). We first identified the expression of miR-361-5p, IL-17A, nuclear factor IA (NFIA), and hes family bHLH transcription factor 1 (Hes1) in serum samples collected from patients with acute pancreatitis, caerulein-induced mice, and a Th17 cell model. The predicted binding of miR-361-5p to NFIA was confirmed in vitro. Gain- and loss-of-function assays of miR-361-5p and NFIA were employed to elucidate their effects on acute pancreatitis. miR-361-5p promoted Th17 cells to secrete IL-17A and then aggravated acute pancreatitis. miR-361-5p directly targeted NFIA by binding to its promoter region, leading to its downregulation. Overexpression of NFIA reduced Hes1 expression and rescued the promoting effect of miR-361-5p on IL-17A secretion. In summary, miR-361-5p enhances IL-17A secretion from Th17 cells and thus aggravates acute pancreatitis by targeting NFIA and upregulating Hes1.

Analysis of miRNA and mRNA reveals core interaction networks and pathways of dexamethasone-induced immunosuppression in chicken bursa of Fabricius

Stress-induced immunosuppression is a serious problem affecting the production value of poultry, but its specific molecular mechanism has not yet been elucidated. We selected 7-day-old Gushi cocks as test animals and successfully established a stress-induced immunosuppression model by injecting 2.0 mg/kg (body weight) dexamethasone (Dex). We then constructed six cDNA libraries and two small RNA libraries of Bursa of Fabricius from the control group and the Dex group. RNA-seq results revealed 21,028 transcripts including 3920 novel transcripts; 500 miRNAs including 68 novel miRNAs were identified. Correlation analysis of miRNA, target genes and mRNA results indicated that the gga-miR-15 family, gga-miR-103-3p, gga-miR-456-3p, and gga-miR-27b-3p, as core differentially expressed miRNAs, may potentially regulate multiple genes which are involved in immune-related pathways; and that the core genes Suppressor of IKBKE 1 (SIKE1) and high mobility group AT-hook 2 (HMGA2) are associated with the miR-17 family (gga-miR-20a-5p, gga-miR-20b-5p, gga-miR-106-5p, and gga-miR-17-5p) and gga-let -7 family (gga-let-7b, gga-let-7i, gga-let-7c-5p, and gga-let-7f-5p). The interaction networks of mRNAs of significantly enrichment pathways and PPI (protein-protein interaction) networks showed that IL6, IL1B, IL8L1, CCL5, SOCS3, SOCS1, ITGB5, GSTA3, SQLE, FDFT1, FN1, IL18, IL10, MAPK11 and MAPK12 are network core nodes and that most of them are strongly associated with immune response. One of the candidate miRNAs, gga-miR-20b-5p, may play an important role in stress-induced immunosuppression. Luciferase assay and over-expression experiments suggested that gga-miR-20b-5p negatively regulated the expression of target gene SIKE1. These results provide better understanding of the mechanism of stress-induced immunosuppression in Gushi chicken bursa, and provide novel targets for subsequent research to improve poultry anti-stress capability.

Comprehensive Analyses of circRNA Expression Profiles and Function Prediction in Chicken Cecums After Eimeria tenella Infection

Coccidiosis is an important intestinal parasitic disease that causes great economic losses to the global poultry production industry. Circular RNAs (circRNAs) are long non-coding RNAs that play important roles in various infectious diseases and inflammatory responses. However, the expression profiles and functions of circRNAs during Eimeria tenella (E. tenella) infection remain unclear. In this study, high-throughput sequencing was carried out to detect circRNAs in chicken cecal tissues from the control (JC), resistant (JR), and susceptible (JS) groups on day 4.5 postinfection (pi), respectively. A total of 104 circRNAs were differentially expressed, including 47 circRNAs between the JS and JC groups, 38 between the JR and JS groups, and 19 between the JR and JC groups. Functional analyses indicated that these differentially expressed circRNAs were involved in pathways related to E. tenella infection; the adaptive immune response was enriched in the JS vs JC group, the NF-kappa B signaling and natural killer cell-mediated cytotoxicity pathways were enriched in the JS vs JC and JR vs JC groups, while the B cell receptor signaling pathway was enriched in only the JR vs JC group. Moreover, the coexpression network of differentially expressed circRNAs and mRNAs suggested that circRNA2202 and circRNA0759 associated with DTX1 in the JS vs JC group, circRNA4338 associated with VPREB3 and CXCL13L3 in the JR vs JC group, and circRNA2612 associated with IL8L1 and F2RL2 in the JR vs JS group were involved in the immune response upon E. tenella infection. In conclusion, our results provide valuable information on the circRNAs involved in the progression of chicken E. tenella infection and advance our understanding of the circRNA regulatory mechanisms of host resistance and susceptibility to E. tenella infection in chickens.

Analysis of miRNA Expression in the Ileum of Broiler Chickens During Bacillus licheniformis H2 Supplementation Against Subclinical Necrotic Enteritis

Subclinical necrotic enteritis (SNE) is one of the serious threats to the poultry industry. Probiotics have been proven to exert beneficial effects in controlling SNE. However, their exact mechanisms have not been fully elucidated. Moreover, few studies have focused on their impact on microRNAs (miRNAs). Therefore, the present study aimed to explore the miRNA expression profiles in the ileum of broiler chickens during probiotic supplementation for controlling SNE. A total of 180 newly hatched male broilers were randomly allocated into three groups, including a negative control group, an SNE infection group, and a Bacillus licheniformis H2 pretreatment group. Illumina high-throughput sequencing was conducted to identify the miRNA expression of the three groups. Results showed that 628 miRNAs, including 582 known miRNAs and 46 novel miRNAs, were detected in the miRNA libraries. The target genes of 57 significantly differentially expressed miRNAs were predicted and annotated. Moreover, they were found to be partly enriched in pathways related to immunity and inflammation such as tumor necrosis factor receptor binding, immune response-regulating signaling pathway, Toll-like receptor 2 signaling pathway, interleukin-15 production, activation of NF-κB-inducing kinase activity, and MAP kinase tyrosine/serine/threonine phosphatase activity. Some of the target genes of 57 miRNAs were related to the MAPK signaling pathway. Furthermore, the expression of several miRNAs, which may be involved in the MAPK signaling pathway, was significantly affected by SNE induction and showed no significant difference in the presence of H2. All these findings provide comprehensive miRNA expression profiles of three different treatment groups. They further suggest that H2 could exert beneficial effects in controlling SNE through immune and inflammatory response associated with altered miRNA expression, such as the MAPK signaling pathway.

Inhibition of ssc-microRNA-140-5p ameliorates the Clostridium perfringens beta2 toxin-induced inflammatory response in IPEC-J2 cells via the ERK1/2 and JNK pathways by targeting VEGFA

Piglet diarrhea and even death due to Clostridium perfringens (C. perfringens) type C infection have led to huge economic losses in the pig industry worldwide. C. perfringens beta2 (CPB2) toxin is the main virulence factor for this pathogen. MiR-140-5p can exacerbate toxin-induced toxicity of toxin to cells by promoting oxidative stress. However, the role of pig miR-140-5p (ssc-miR-140-5p) in piglet diarrhea caused by C. perfringens type C has not been studied. Here, we study investigated the function of ssc-miR-140-5p by generating an in vitro CPB2-induced injury model in intestinal porcine epithelial (IPEC-J2) cells. Our results revealed that transfection with an ssc-miR-140-5p inhibitor significantly increased the viability of CPB2-induced IPEC-J2 cells, decrease the release of lactate dehydrogenase (LDH) and reactive oxygen species (ROS), and inhibit inflammatory responses and apoptosis. In addition, vascular endothelial growth factor A (VEGFA) was identified as a direct target of ssc-miR-140-5p by luciferase reporter assay. Western blot analysis showed that inhibition of ssc-miR-140-5p could activate the ERK1/2 signaling pathway and inhibit the JNK signaling pathway. In summary, we showed that down-regulation of ssc-miR-140-5p ameliorated CPB2-induced inflammatory responses in IPEC-J2 cells via the ERK1/2 and JNK signaling pathways by targeting VEGFA.

Epigenetic Regulation by Non-Coding RNAs in the Avian Immune System

The identified non-coding RNAs (ncRNAs) include circular RNAs, long non-coding RNAs, microRNAs, ribosomal RNAs, small interfering RNAs, small nuclear RNAs, piwi-interacting RNAs, and transfer RNAs, etc. Among them, long non-coding RNAs, circular RNAs, and microRNAs are regulatory RNAs that have different functional mechanisms and were extensively participated in various biological processes. Numerous research studies have found that circular RNAs, long non-coding RNAs, and microRNAs played their important roles in avian immune system during the infection of parasites, virus, or bacterium. Here, we specifically review and expand this knowledge with current advances of circular RNAs, long non-coding RNAs, and microRNAs in the regulation of different avian diseases and discuss their functional mechanisms in response to avian diseases.

MicroRNA Profiling Reveals an Abundant miR-200a-3p Promotes Skeletal Muscle Satellite Cell Development by Targeting TGF-β2 and Regulating the TGF‑β2/SMAD Signaling Pathway

MicroRNAs (miRNAs) are evolutionarily conserved, small noncoding RNAs that play critical post-transcriptional regulatory roles in skeletal muscle development. Chicken is an optimal model to study skeletal muscle formation because its developmental anatomy is similar to that of mammals. In this study, we identified potential miRNAs in the breast muscle of broilers and layers at embryonic day 10 (E10), E13, E16, and E19. We detected 1836 miRNAs, 233 of which were differentially expressed between broilers and layers. In particular, miRNA-200a-3p was significantly more highly expressed in broilers than layers at three time points. In vitro experiments showed that miR-200a-3p accelerated differentiation and proliferation of chicken skeletal muscle satellite cells (SMSCs) and inhibited SMSCs apoptosis. The transforming growth factor 2 (TGF-β2) was identified as a target gene of miR-200a-3p, and which turned out to inhibit differentiation and proliferation, and promote apoptosis of SMSCs. Exogenous TGF-β2 increased the abundances of phosphorylated SMAD2 and SMAD3 proteins, and a miR-200a-3p mimic weakened this effect. The TGF-β2 inhibitor treatment reduced the promotional and inhibitory effects of miR-200a-3p on SMSC differentiation and apoptosis, respectively. Our results indicate that miRNAs are abundantly expressed during embryonic skeletal muscle development, and that miR-200a-3p promotes SMSC development by targeting TGF-β2 and regulating the TGF-β2/SMAD signaling pathway.