Identification and expression analysis of duck interleukin-17D in Riemerella anatipestifer infection

Identification of Critical Immune Regulators and Potential Interactions of IL-26 in Riemerella anatipestifer-Infected Ducks by Transcriptome Analysis and Profiling

Riemerella anatipestifer (RA) is an economically important pathogen in the duck industry worldwide that causes high mortality and morbidity in infected birds. We previously found that upregulated IL-17A expression in ducks infected with RA participates in the pathogenesis of the disease, but this mechanism is not linked to IL-23, which primarily promotes Th17 cell differentiation and proliferation. RNA sequencing analysis was used in this study to investigate other mechanisms of IL-17A upregulation in RA infection. A possible interaction of IL-26 and IL-17 was discovered, highlighting the potential of IL-26 as a novel upstream cytokine that can regulate IL-17A during RA infection. Additionally, this process identified several important pathways and genes related to the complex networks and potential regulation of the host immune response in RA-infected ducks. Collectively, these findings not only serve as a roadmap for our understanding of RA infection and the development of new immunotherapeutic approaches for this disease, but they also provide an opportunity to understand the immune system of ducks.

Evolution of developmental and comparative immunology in poultry: The regulators and the regulated

Avian has a unique immune system that evolved in response to environmental pressures in all aspects of innate and adaptive immune responses, including localized and circulating lymphocytes, diversity of immunoglobulin repertoire, and various cytokines and chemokines. All of these attributes make birds an indispensable vertebrate model for studying the fundamental immunological concepts and comparative immunology. However, research on the immune system in birds lags far behind that of humans, mice, and other agricultural animal species, and limited immune tools have hindered the adequate application of birds as disease models for mammalian systems. An in-depth understanding of the avian immune system relies on the detailed studies of various regulated and regulatory mediators, such as cell surface antigens, cytokines, and chemokines. Here, we review current knowledge centered on the roles of avian cell surface antigens, cytokines, chemokines, and beyond. Moreover, we provide an update on recent progress in this rapidly developing field of study with respect to the availability of immune reagents that will facilitate the study of regulatory and regulated components of poultry immunity. The new information on avian immunity and available immune tools will benefit avian researchers and evolutionary biologists in conducting fundamental and applied research.

The efficacy and safety of adjunctive Perampanel for the treatment of refractory focal-onset seizures in patients with epilepsy:A meta-analysis

Objective

The last decade has seen an increase in the use of anti‐seizure medications (ASMs); however, the burden of treating drug‐resistant epilepsy has not fallen. We performed this meta‐analysis to evaluate the optimal dose of Perampanel (PER) as a new adjunctive treatment for drug‐resistant seizures.

Methods

We searched for studies published from inception to February 1, 2021 from PubMed, Central Register of Controlled Trials (CENTRAL), and ScienceDirect. Research characteristics, patients' characteristics, and treatment regimen, concomitant ASMs, clinical outcomes were extracted. The practical outcome included a reduction in seizures frequency ≥50%, ≥75%, and ≥100% from baseline convulsive seizure frequency, and the safety outcome included the proportion of drug withdrawal and adverse reactions. Odds ratios (OR) for 95% confidence intervals (95% CI) were estimated by the inverse variance method.

Results

Four trials which enrolled 2187 participants (1569 in the PER group and 618 in the placebo group) were included. Results showed that 8 or 12 mg per day had the best effect on all three outcomes, with no significant difference between 8 and 12 mg per day (≥50% reduction, 35.5% vs 36.1%, P = .84; ≥75% reduction, 17.8% vs 19.1%, P = .64; seizure‐free, 3.5% vs 3.7%, P = .85). In addition, 12‐mg PER compared to 8 mg had a higher proportion of trial withdrawal (8.7% vs 17.0%; P < .00001) and treatment‐emergent adverse event (TEAE) resulting in dose reduction/discontinuation (18.5% vs 32.0%; P < .00001). The adverse events (AEs) significantly associated with adjunctive PER were dizziness, somnolence, fatigue, and irritability.

Significance

Adjunctive treatment of PER was associated with a more significant reduction in the frequency of seizures in patients with refractory epilepsy than placebo, but with a higher frequency of AEs. PER at a daily dose of 8 mg appears to have the best ratio between efficacy and tolerance in most study participants.

Duck Interleukin-22: Identification and Expression Analysis in Riemerella anatipestifer Infection

Riemerella anatipestifer is one of the most devastating pathogens affecting the global duck farms. Infection is involved in secretion of proinflammatory cytokines, including interleukin- (IL-) 17A. During the immune response to infection, IL-22 and IL-17A are often produced concurrently and at high levels in inflamed tissues. Little is known about duck IL-22 (duIL-22) during R. anatipestifer infection. We describe the characterization of duIL-22 and its mRNA expression analysis in splenic lymphocytes and macrophages treated with heat-killed R. anatipestifer and in the spleens and livers of R. anatipestifer-infected ducks. Full-length cDNA of duIL-22 encoded 197 amino acids. The deduced amino acid sequence of duIL-22 shared a 30.4-40.5% similarity with piscine counterparts, 57.4-60.1% with mammalian homologs, and 93.4% similarity to the chicken. Duck IL-22 mRNA expression level was relatively high in the skin of normal ducks. It was increased in mitogen-stimulated splenic lymphocytes and in killed R. anatipestifer-activated splenic lymphocytes and macrophages. Compared with healthy ducks, IL-22 transcript expression was significantly upregulated in the livers and spleens on days 1 and 4 postinfection, but not on day 7. IL-17A was significantly increased in the spleens only on day 4 postinfection and in the livers at all time points. When splenic lymphocytes were stimulated with heat-killed R. anatipestifer, CD4+ cells predominantly produced IL-22 while IL-17A was expressed both by CD4+ and CD4- cells. These results suggested that IL-22 and IL-17A are likely expressed in different cell types during R. anatipestifer infection.

Anti-inflammatory activity of diindolylmethane alleviates Riemerella anatipestifer infection in ducks

3,3’-Diindolylmethane (DIM) is found in cruciferous vegetables and is used to treat various inflammatory diseases because of its potential anti-inflammatory effects. To investigate effects of DIM in Riemerella anatipestifer-infected ducks which induce upregulation of inflammatory cytokines, ducks were treated orally with DIM at dose of 200 mg/kg/day and infected the following day with R. anatipestifer. Infected and DIM-treated ducks exhibited 14% increased survival rate and significantly decreased bacterial burden compared to infected untreated ducks. Next, the effect on the expression level of inflammatory cytokines (interleukin [IL]-17A, IL-17F, IL-6, IL-1β) of both in vitro and in vivo DIM-treated groups was monitored by quantitative reverse-transcription PCR (qRT-PCR). Generally, the expression levels of the cytokines were significantly reduced in DIM-treated splenic lymphocytes stimulated with killed R. anatipestifer compared to stimulated untreated splenic lymphocytes. Similarly, the expression levels of the cytokines were significantly reduced in the spleens and livers of DIM-treated R. anatipestifer–infected ducks compared to infected untreated ducks. This study demonstrated the ameliorative effects of DIM in ducks infected with R. anatipestifer. Thus, DIM can potentially be used to prevent and/or treat R. anatipestifer infection via inhibition of inflammatory cytokine expression.

Involvement of nuclear factor erythroid 2‑related factor 2 in neonatal intestinal interleukin‑17D expression in hyperoxia

Interleukin 17D (IL-17D) plays an important role in host defense against inflammation and infection. In the present study, the role of nuclear factor erythroid 2-related factor 2 (Nrf2) in regulating the production of IL-17D was investigated under hyperoxia. For this purpose, neonatal rats were randomized into two groups; the model group was exposed to hyperoxia (80-85% O₂), while the control group was maintained under normoxic conditions (21% O₂). Small intestine tissue was collected on postnatal days 3, 7, 10 and 14. IL-17D expression was detected by immunofluorescence, immunohistochemistry and western blotting. The levels of Nrf2 and kelch-like ECH-associated protein 1 (keap1) were detected by immunohistochemistry and western blotting. Results showed that IL-17D expression in intestine epithelial cells increased steadily, reaching a peak on day 7, and decreased gradually on days 10 and 14 under hyperoxia. Nrf2 expression was consis-tent with IL-17D, and it was positively correlated with IL-17D. However, on postnatal days 10 and 14, the number of CD4⁺ T cells and CD19⁺ B cells expressing IL-17D was increased, and positive cells of the model group were significantly more than that of the control group. Keap1 levels were lower at the early stage. In conclusion, the expression levels of intestinal IL-17D and Nrf2 were altered simultaneously following neonatal rat development in hyperoxia, indicating that Nrf2 may be involved in regulating the expression of IL-17D in intestinal epithelial cells. Moreover, IL-17D in intestinal epithelial cells may play a unique immunological role during hyperoxia.

IL-17A treatment influences murine susceptibility to experimental Riemerella anatipestifer infection

Riemerella anatipestifer causes infectious disease and considerable economic loss in the duck industry worldwide. Our previous studies demonstrated an association between proinflammatory cytokine interleukin (IL)-17A and R. anatipestifer infection. Here, we provide evidence for IL-17A involvement in R. anatipestifer infection using a mouse model. Mice showed higher resistance to R. anatipestifer infection than ducks, with median lethal doses (LD₅₀) of 3.5 × 10¹⁰ and 5 × 10⁷ colony-forming units (CFU), respectively. Twenty-four hours after infection, mice with a sub-lethal dose (3.5 × 10⁹ CFU) exhibited levels of IL-17A and IL-23 expression similar to uninfected mice. Thus, we hypothesized that exogenous IL-17A or IL-23 administration affects susceptibility of mice to R. anatipestifer. Mice pretreated with IL-17A or IL-23 prior to sub-lethal dose infection of R. anatipestifer exhibited increased bacterial burden and spleen weights compared to untreated infected mice, confirming the involvement of IL-17A in susceptibility to R. anatipestifer infection in vivo.

Riemerella anatipestifer infection in ducks induces IL-17A production, but not IL-23p19

R. anatipestifer (RA) is one of the most harmful bacterial pathogens affecting the duck industry, and infection is associated with the production of proinflammatory cytokines, including IL-17A. Another proinflammatory cytokine, IL-23, is critical for the development of Th17 cells, which produce IL-17. However, IL-23 roles have not been studied in this infection. Here, we describe the identification and mRNA expression analysis of duck IL-23p19 (duIL-23p19) in splenic lymphocytes and macrophages stimulated with killed RA and in spleens of RA-infected ducks. Expression of duIL-23p19 transcript identified in this study was relatively high in livers of healthy ducks and was upregulated in mitogen-activated splenic lymphocytes as well as in splenic lymphocytes and macrophages stimulated with killed RA. In spleens of RA-infected ducks, expression levels of duIL-23p19 transcript were unchanged at all time points except on days 4 and 7 post-infection; however, duIL-17A and IL-17F expression levels were upregulated in both spleens of RA-infected ducks and splenic lymphocytes and macrophages stimulated with killed RA. In sera collected at 24 h after this infection, duIL-23p19 expression levels were unchanged, whereas IL-17A significantly upregulated. These results suggest that IL-23p19 does not play a critical role in the IL-17A response in early stages of RA-infected ducks.

Downregulation of common cytokine receptor γ chain inhibits inflammatory responses in macrophages stimulated with Riemerella anatipestifer

Th17-cell-mediated inflammation is affected by the soluble form of common cytokine receptor γ chain (γ_c). We previously suggested that inflammatory cytokines including interleukin (IL)-17A are associated with Riemerella anatipestifer infection, which a harmful bacterial pathogen in ducks. Here, the expression profiles of membrane-associated γ_c (duγ_c-a) and soluble γ_c (duγ_c-b) in R. anatipestifer-stimulated splenic lymphocytes and macrophages, and in the spleens and livers of R. anatipestifer-infected ducks, were investigated. In vitro and in vivo results indicated that the expression levels of both forms of γ_c were increased, showing that marked increases were detected in the expression of the duγ_c-b form rather than the duγ_c-a form. Treatment with γ_c-specific siRNA downregulated mRNA expression of Th17-related cytokines, including IL-17A and IL-17F, in duck splenic macrophages stimulated with R. anatipestifer, whereas the expressions of interferon (IFN)-γ and IL-2 were enhanced. The results showed that the upregulation of γ_c, especially the duγ_c-b form, was associated with expression of Th17-related cytokines during R. anatipestifer infection.

Downregulation of inflammatory cytokines by berberine attenuates Riemerella anatipestifer infection in ducks

Riemerella anatipestifer, an important infectious bacterium affecting the duck industry, has 5-75% mortality, depending on strain virulence. We previously demonstrated that proinflammatory cytokines are involved in inflammation during, and regulating susceptibility to, R. anatipestifer infection. We investigated the effects of the anti-inflammatory compound berberine in duck splenic lymphocytes stimulated with killed R. anatipestifer, and in R. anatipestifer-infected ducks. IL-17A, IL-17F, and IL-1β transcripts were downregulated, and IFN-γ and IL-10 transcripts enhanced, in berberine-treated stimulated splenic lymphocytes, compared to stimulated untreated splenic lymphocytes. Similarly, IL-17A, IL-17F, IL-6, and IL-1β expressions were significantly reduced, and IFN-γ and IL-10 expressions significantly upregulated, in spleens and livers of R. anatipestifer-infected berberine-treated ducks, compared to infected untreated birds. Moreover, infected and treated birds showed increased survival rates and significantly decreased bacterial burdens compared to infected untreated birds, confirming that inflammatory cytokines are strongly associated with R. anatipestifer infection in ducks.

Peritoneal bacterial infection repressed the expression of IL17D in Siberia sturgeon a chondrostean fish in the early immune response

IL17s are pro-inflammatory cytokines that play important roles in host fighting against extracellular bacteria and auto-immune and allergic diseases. IL17D is believed to be the most ancient IL17 member and its functions are far from clarity. Although it has been found in invertebrates, jawless fish, teleosts, and tetrapods, it has not been described in chondrostean fish. Moreover, there are discrepancies concerning its expression pattern in these animals. In this study, we cloned and characterized the cDNA of il17d in Siberia sturgeon (Acipenser baerii), a chondrostean fish and commercially important species in aquaculture. The sturgeon il17d cDNA encodes a deduced protein of 210aa. The classical characteristics of IL17, such as IL17 domain, cysteine and serine residues importantly for cystine-knot formation, and signal peptide, were observed in sturgeon IL17D. Phylogenetic analysis and multiple alignment suggest it is a counterpart of mammalian IL17D. However, in vivo studies demonstrated that the expression pattern of sturgeon il17d mRNA is different from that of other teleosts and jawless fish, and in most cases its expression was down-regulated at the early time points and gradually increasing at late time points when sturgeon were challenged with bacteria (Aernomas hydrophila or Staphylococcus aureus). The In vitro study by using primary spleen cells stimulated with polyI:C revealed a similar expression pattern to that in vivo studies, while the stimulation with β-glucan or LPS, which normally induced expression of il17d mRNA in target cells in vitro in other animals, did not show apparent changes in the expression of il17d mRNA. The results of present study indicated sturgeon IL17D may possess some different characteristics from its counterparts of other fish and invertebrates in the immune response, and may contribute to the understanding of IL17D functions in evolution as well as the potential use in sturgeon aquaculture.