Salmonella infection may alter the expression of toll like receptor 4 and immune related cells in chicken bursa of Fabricius

Reduction of microRNA-221 in BVDV infection enhances viral replication by targeting the ATG7-mediated autophagy pathway

BACKGROUND

Bovine viral diarrhoea (BVD), a condition triggered by bovine viral diarrhoea virus (BVDV), is recognized globally as a prevalent pathogen among ruminants and markedly affects the economics of animal husbandry. MicroRNAs, a class of small noncoding RNAs, play pivotal roles in regulating a myriad of biological processes.The ATG7-LC3 pathway, a canonical autophagy mechanism, is integral in defending against pathogenic invasion and maintaining cellular homeostasis.

RESULTS

In this study, we observed significant downregulation of bta-miR-221 in cells infected with BVDV. We further established that overexpression of bta-miR-221 markedly attenuated BVDV replication in Madin‒Darby bovine kidney (MDBK) cells. Through bioinformatics prediction analysis, we identified ATG7, an autophagy-related gene, as a direct downstream target of bta-miR-221. However, the intricate relationships among bta-miR-221, the ATG7-LC3 pathway, and BVDV infection remained unclear. Our study revealed that ATG7 expression was significantly elevated in BVDV-infected cells, whereas bta-miR-221 mimics repressed both endogenous and exogenous ATG7 expression. Following BVDV infection, we noted a decrease in LC3I expression, its conversion to LC3II, a significant increase in ATG7 expression, and a notable decrease in SQSTM1/p62 expression. By employing laser confocal microscopy and immunoprecipitation assays, we elucidated the regulation of the ATG7-LC3 pathway by bta-miR-221 in MDBK cells. Our findings recealed that BVDV infection enhanced the ATG7-LC3 interaction, inducing autophagy through the suppression of bta-miR-221 in MDBK cells. Consequently, bta-miR-221 emerged as a potent inhibitor of BVDV, impacting its proliferation and replication within the host.

CONCLUSIONS

This research sheds light on novel aspects of virus-host interactions and lays a foundation for the development of antiviral therapeutics.

Two mutations at KRT74 and EDAR synergistically drive the fine-wool production in Chinese sheep

INTRODUCTION

Fine-wool sheep are the most common breed used by the wool industry worldwide. Fine-wool sheep have over a three-fold higher follicle density and a 50% smaller fiber diameter than coarse-wool sheep.

OBJECTIVES

This study aims to clarify the underlying genetic basis for the denser and finer wool phenotype in fine-wool breeds.

METHOD

Whole-genome sequences of 140 samples, Ovine HD630K SNP array data of 385 samples, including fine, semi-fine, and coarse wool sheep, as well as skin transcriptomes of nine samples were integrated for genomic selection signature analysis.

RESULTS

Two loci at keratin 74 (KRT74) and ectodysplasin receptor (EDAR) were revealed. Fine-scale analysis in 250 fine/semi-fine and 198 coarse wool sheep narrowed this association to one C/A missense variant of KRT74 (OAR3:133,486,008, P = 1.02E-67) and one T/C SNP in the regulatory region upstream of EDAR (OAR3:61,927,840, P = 2.50E-43). Cellular over-expression and ovine skin section staining assays confirmed that C-KRT74 activated the KRT74 protein and specifically enlarged cell size at the Huxley's layer of the inner root sheath (P < 0.01). This structure enhancement shapes the growing hair shaft into the finer wool than the wild type. Luciferase assays validated that the C-to-T mutation upregulated EDAR mRNA expression via a newly created SOX2 binding site and potentially led to the formation of more hair placodes.

CONCLUSIONS

Two functional mutations driving finer and denser wool production were characterized and offered new targets for genetic breeding during wool sheep selection. This study not only provides a theoretical basis for future selection of fine wool sheep breeds but also contributes to improving the value of wool commodities.

Transcriptome and proteome profile of jejunum in chickens challenged with Salmonella Typhimurium revealed the effects of dietary bilberry anthocyanin on immune function

Introduction

The present study investigated the effects of bilberry anthocyanin (BA) on immune function when alleviating Salmonella Typhimurium (S. Typhimurium) infection in chickens.

Methods

A total of 180 newly hatched yellow-feathered male chicks were assigned to three groups (CON, SI, and SI + BA). Birds in CON and SI were fed a basal diet, and those in SI + BA were supplemented with 100 mg/kg BA for 18 days. Birds in SI and SI + BA received 0.5 ml suspension of S. Typhimurium (2 × 109 CFU/ml) by oral gavage at 14 and 16 days of age, and those in CON received equal volumes of sterile PBS.

Results

At day 18, (1) dietary BA alleviated weight loss of chickens caused by S. Typhimurium infection (P < 0.01). (2) Supplementation with BA reduced the relative weight of the bursa of Fabricius (P < 0.01) and jejunal villus height (P < 0.05) and increased the number of goblet cells (P < 0.01) and the expression of MUC2 (P < 0.05) in jejunal mucosa, compared with birds in SI. (3) Supplementation with BA decreased (P < 0.05) the concentration of immunoglobulins and cytokines in plasma (IgA, IL-1β, IL-8, and IFN-β) and jejunal mucosa (IgG, IgM, sIgA, IL-1β, IL-6, IL-8, TNF-α, IFN-β, and IFN-γ) of S. Typhimurium-infected chickens. (4) BA regulated a variety of biological processes, especially the defense response to bacteria and humoral immune response, and suppressed cytokine-cytokine receptor interaction and intestinal immune network for IgA production pathways by downregulating 6 immune-related proteins.

Conclusion

In summary, the impaired growth performance and disruption of jejunal morphology caused by S. Typhimurium were alleviated by dietary BA by affecting the expression of immune-related genes and proteins, and signaling pathways are related to immune response associated with immune cytokine receptors and production in jejunum.

Intracloacal Inoculation of Broiler Chickens with Clostridium perfringens Strains: Evaluation of Necrotic Enteritis Disease Development and Lymphoid Immune Responses

Necrotic enteritis (NE) is an economically important disease of chickens. We have recently shown that inflammatory responses in chickens inoculated orally with virulent Clostridium perfringens were spatially regulated. Here, we used previously virulence-characterized netB+ C. perfringens strains, avirulent CP5 and virulent CP18 and CP26, to assess the severity of NE and immune responses in broiler chickens when inoculated intracloacally. The results showed that CP18- and CP26-infected birds had a reduced weight gain and developed milder/less severe NE lesions, as determined by the gross lesions scores, suggesting a subclinical-grade infection. Gene expression analysis in infected birds revealed three statistically significant observations compared to uninfected-control: (1) Increased expression of anti-inflammatory/immunoregulatory interleukin (IL)-10/transforming growth factor (TGF)β in cecal tonsil (CT) and bursa of Fabricius in the CP18/CP26-infected groups. (2) Increased CT transcription of pro-inflammatory IL-1β, IL-6 and interferon (IFN)γ and decreased Harderian gland (HG) expression of IFNγ in the CP18/CP26-infected birds. (3) Increased HG or bursal expression of IL-4 and IL-13 in CP5-infected birds. Collectively, intracloacal C. perfringens inoculation seems to induce a highly regulated inflammatory response in the CT and other mucosal lymphoid organs and an intracloacal infection model may be useful in evaluating immune responses in chickens with subclinical NE.

Curcumin mitigates Cryptosporidium parvum infection through modulation of gut microbiota and innate immune-related genes in immunosuppressed neonatal mice

Cryptosporidium parvum is a major cause of diarrheal disease in immature or weakened immune systems, mainly in infants and young children in resource-poor settings. Despite its high prevalence, fully effective and safe drugs for the treatment of C. parvum infections remain scarce, and there is no vaccine. Meanwhile, curcumin has shown protective effects against C. parvum infections. However, the mechanisms of action and relationship to the gut microbiota and innate immune responses are unclear. Immunosuppressed neonatal mice were infected with oocysts of C. parvum and either untreated or treated with a normal diet, curcumin or paromomycin. We found that curcumin stopped C. parvum oocysts shedding in the feces of infected immunosuppressed neonatal mice, prevented epithelial damage, and villi degeneration, as well as prevented recurrence of infection. Curcumin supplementation increased the relative abundance of Bacteroidetes and decreased the relative abundance of Firmicutes and Proteobacteria in mice infected with C. parvum as shown by 16S rRNA gene sequencing analysis. The relative abundance of Lactobacillus, Bacteroides, Akkermansia, Desulfovibrio, Prevotella, and Helicobacter was significantly associated with C. parvum infection inhibited by curcumin. Curcumin significantly (P < 0.01) suppressed IFN-γ and IL -18 gene expression levels in immunosuppressed neonatal C. parvum-infected mice. We demonstrate that the therapeutic effects curcumin are associated with alterations in the gut microbiota and innate immune-related genes, which may be linked to the anti-Cryptosporidium mechanisms of curcumin.

The Chicken Embryo Model: A Novel and Relevant Model for Immune-Based Studies

Dysregulation of the immune system is associated with many pathologies, including cardiovascular diseases, diabetes, and cancer. To date, the most commonly used models in biomedical research are rodents, and despite the various advantages they offer, their use also raises numerous drawbacks. Recently, another in vivo model, the chicken embryo and its chorioallantoic membrane, has re-emerged for various applications. This model has many benefits compared to other classical models, as it is cost-effective, time-efficient, and easier to use. In this review, we explain how the chicken embryo can be used as a model for immune-based studies, as it gradually develops an embryonic immune system, yet which is functionally similar to humans'. We mainly aim to describe the avian immune system, highlighting the differences and similarities with the human immune system, including the repertoire of lymphoid tissues, immune cells, and other key features. We also describe the general in ovo immune ontogeny. In conclusion, we expect that this review will help future studies better tailor their use of the chicken embryo model for testing specific experimental hypotheses or performing preclinical testing.

Effects of lime (Citrus aurantifolia) peel to the expression of mRNA toll-like receptors 4 in balb/c mice-infected Salmonella typhi

Lime peel contains metabolic compounds that have lethal effects of bacterial cells, but its effect as an antibacterial modulate innate immunity pathways, especially toll-like receptor 4 (TLR-4) signaling pathway, is unclear. This study examined the effects of lime peel extract (LPE) on the activity of TLR 4 in Balb/c mice induced by Salmonella typhi. Mice were induced intraperitoneally and then 3 days after induction, LPE was given orally on two doses (510 and 750 mg/kg BW). The number of bacterial colonization was counted using peritoneal fluid samples by the method of plate count agar. Intervention LPE for 5 days can degrade TLR-4 and the number of colonies of S. typhi. On day 3 after was induced S. typhi, TLR-4 gene expression of Balb/c mice is increased. Postintervention LPE for 5 days, the expression of TLR-4 gene decreased, significantly different at a dose of 750 mg/kg BW (P = 0.04). There was a positive correlation between the expression of TLR-4 gene by the number of bacterial colonization, decreasing gene expression of TLR-4, the number of bacterial colonization is also getting smaller (P = 0.013, r = 0.408). LPE can modulate the TLR-4 signaling pathway in host immunity so that the gene TLR-4 is expressed fewer in numbers. This mechanism causes the bacterial colony number to decrease, not even growth.

The morphological basis of the development of the chick embryo immune system

The chick immune system is a fundamental model in basic immunology. In birds, the bone marrow derived pluripotent stem cells after entering the circulation, migrate to bursa of Fabricius to benefit from a microenvironment which supports the differentiation and maturation of B lymphocytes by the help of its resident cells and tissues. Delivering sufficient functional B cells is required to maintain their peripheral population and normal peripheral humoral responses. Additionally, bursa acts as an active site for the generation of antibody diversity through gene conversion. Being consisted of 98% B lymphocytes, the organ is occupied by other cell types including T cells, macrophages, eosinophils and mast cells. Thymus, which is an epithelial organ is the main site of T cell development where positive and negative selections contribute to the development of functional and not autoreactive T cell repertoire. Bursectomy and thymectomy are surgical exercises through which the involvement of cells of specific immunity including B cells and T cells can be determined.