Elevated level of pro inflammatory cytokine and chemokine expression in chicken bone marrow and monocyte derived dendritic cells following LPS induced maturation

Bothrops atrox snake venom decreased MHC-II and CD86 expression in bone marrow-derived dendritic cells

The effect of Bothrops atrox venom (BaV) on the maturation of bone marrow-derived dendritic cells (BMDCs) from mice was investigated, with a focus on selected cell markers, TAP1 expression, and the release of pro-inflammatory cytokines during this process. The objective was to evaluate BaV's impact on dendritic cell (DC) function, as DCs are pivotal in antigen presentation and responsible for initiating the immune response mediated by naïve T cells, as well as regulating the immune system. Bone marrow cells were obtained from Swiss mice, and hematopoietic precursors were differentiated into BMDCs using GM-CSF and IL-4. On the 7th day, BaV and LPS were introduced into the culture, and the cells were analyzed 24 h later. BaV's ability to stimulate BMDC maturation was assessed through the analysis of surface marker expression. The findings demonstrated that BMDCs are highly influenced by culture environment factors, such as GM-CSF and IL-4, and are sensitive to additional stimuli like LPS and BaV. Mature DCs exhibited elevated levels of critical markers for T cell activation, such as MHC-II, CD80, and CD86, displaying specific phenotypic characteristics. However, the observed reduction in MHC-II and CD86 expression following BaV exposure suggests a substantial impact on the immunological activation capacity of these cells, potentially interfering with the adaptive immune response. Furthermore, the selective release of cytokines, such as IL-6, but not TNF-α or IL-1β, indicates differentiated modulation of inflammatory responses by DCs under various stimulation conditions.

Leverage of Salvadora persica and Pulicaria undulata extracts in Escherichia coli-challenged broiler chickens

Escherichia coli (E. coli) is a significant challenge in the poultry industry due to their related use of antimicrobial compounds and the drastic losses in production and livability. This study investigated the preventive impacts of dietary supplementation of Salvadora persica (SP) and/or Pulicaria undulata (PU) extracts on growth traits, biochemical and immune parameters, and related gene expression of E. coli-infected broilers. A total of 120 one-day-old Cobb broilers were used. The chicks were allocated into eight equal groups (3 replicates/ group; 5 chicks per each replicate) as follows: G1; control negative, G2; SP-treated, G3; PU-treated, G4; SP/PU-treated, G5; E. coli infected, G6; E. coli infected and SP-treated, G7; E. coli infected and PU-treated, G8; E. coli infected and SP/PU-treated groups. Results revealed significant improvement in average body weight (ABW), average weight gain (AWG) and feed conversion ratio (FCR) in broilers fed diets supplemented with SP and/or PU compared to control and E. coli infected groups. Moreover, significant (P < 0.05) reduction in ALT, AST, creatinine, and uric acid was reported in other treated groups compared to the single E. coli-infected broilers. On the contrary, a significant increase (P < 0.05) in serum immunoglobulin and protein concentration was also reported in treated groups when compared to E. coli-infected untreated group. In addition, feeding broilers with SP and/or PU significantly improved (P < 0.05) the relative weight of immune-related organs and gene expression of TLR-15, with subsequent down-regulation of IL-1β and TNF-α mRNA transcripts. Supplementing broilers with dietary SP and/or PU could be promising in the prevention of E. coli infection via stimulating significant improvement of immune-related gene expression, immune-related organ weight, and down-regulation of inflammatory-related genes, with subsequent enhancement of the growth performance of broiler chickens.

Leptin/lipopolysaccharide-treated dendritic cell vaccine improved cellular immune responses in an animal model of breast cancer

PURPOSE

In dendritic cells (DCs), leptin as an immune-regulating hormone, increases the IL-12 generation whereas it reduces the IL-10 production, thus contributing to TH1 cell differentiation. Using a murine model of breast cancer (BC), we evaluated the impacts of the Leptin and/or lipopolysaccharide (LPS)-treated DC vaccine on various T-cell-related immunological markers.

MATERIALS AND METHODS

Tumors were established in mice by subcutaneously injecting 7 × 105 4T1 cells into the right flank. Mice received the DC vaccines pretreated with Leptin, LPS, and both Leptin/LPS, on days 12 and 19 following tumor induction. The animals were sacrificed on day 26 and after that the frequency of the splenic cytotoxic T lymphocytes (CTLs) and TH1 cells; interferon gamma (IFN-γ), interleukin 12 (IL-12) and tumor growth factor beta (TGF-β) generation by tumor lysate-stimulated spleen cells, and the mRNA expression of T-bet, FOXP3 and Granzyme B in the tumors were measured with flow cytometry, ELISA and real-time PCR methods, respectively.

RESULTS

Leptin/LPS-treated mDC group was more efficient in blunting tumor growth (p = .0002), increasing survival rate (p = .001), and preventing metastasis in comparison with the untreated tumor-bearing mice (UT-control). In comparison to the UT-control group, treatment with Leptin/LPS-treated mDC also significantly increased the splenic frequencies of CTLs (p < .001) and TH1 cells (p < .01); promoted the production of IFN-γ (p < .0001) and IL-12 (p < .001) by splenocytes; enhanced the T-bet (p < .05) and Granzyme B (p < .001) expression, whereas decreased the TGF-β and FOXP3 expression (p < .05).

CONCLUSION

Compared to the Leptin-treated mDC and LPS-treated mDC vaccines, the Leptin/LPS-treated mDC vaccine was more effective in inhibiting BC development and boosting immune responses against tumor.

Bothrops jararacussu snake venom decreases CD1d, CD83, and CD86 expression on bone marrow-derived dendritic cells

This study was designed to characterize mice bone marrow (BM) and bone marrow-derived dendritic cells (BMDC) and to compare the surface markers expression and inflammatory cytokine liberation in response to LPS and Bothrops jararacussu venom (BjV) stimulation. Typical morphology was observed in BM and BMDCs from the 4th up to the 8th day of culture using recombinant mouse GM-CSF and IL-4. A high basal level of MHC-II, CD1d, CD83, CD11c, CD80, and low CD86 was expressed by BM cells. After stimulation with GM-CSF/IL-4 for BMDCs differentiation, the BM cells differentiated into BMDCs presented MHC-II, CD1d, CD83, CD11c, CD86, and CD80 expression on the 4th - 8th day accompanied with high levels of TNF-α liberated. The difference between the surface markers' expression was observed in this time course in which CD1d, CD11c, and CD80 remained in high levels of expression, while MHC-II and CD83 showed moderate expression during the differentiation period. Also, cytokines liberation was monitored over the period of the BMDCs culture, and on the 6th day, low levels of IL-6 and IL-1β were found, while high levels of TNF-α on the 4th and 8th days, both of which contributed to the maturity of the BMDCs. Maturation of DCs with LPS showed significant upregulation of surface markers (MHC-II, CD1d, CD83, CD86, CD80) and pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) liberation. On the other hand, BjV induced a decrease in CD1d, CD11c, CD83, and CD86 expression in mature BMDCs which was not observed when LPS was used to stimulate BMDCs which probably induces impairment in T-cell activation.

Expression of toll-like receptor 4 and its associated cytokines from peripheral blood mononuclear cells in Leghorn chickens

Background and Aim

Immune cells require toll-like receptor 4 (TLR4) to respond to lipopolysaccharides (LPS) by releasing pro-inflammatory cytokines. Peripheral blood mononuclear cells (PBMCs) are used to assess changes in cytokines released in response to diseases or pathogens. This study aimed to assess TLR4 gene expression in PBMCs from Leghorn chicken and the release of related cytokines.

Materials and Methods

Peripheral blood mononuclear cells were isolated from blood samples obtained from Leghorn chicks. The PBMC cultures were stimulated with various concentrations of LPS (0.01-1 μg/ml). Polymerase chain reaction was used to detect TLR4 expression. The production of tumor necrosis factor-alpha (TNF-α) and interleukins (IL-1β and IL-6) was quantified using an enzyme-linked immunosorbent assay.

Results

We found that TLR4 was expressed in both non-stimulated and stimulated Leghorn chicken PBMCs. In addition, the release of TNF-α, IL-1β, and IL-6 levels in Leghorn chicken PBMCs increased significantly with an increase in LPS concentration (0.01-1 μg/mL) (p < 0.05).

Conclusion

Although TLR4 was expressed in both non-stimulated and stimulated Leghorn chicken PBMCs, its expression was significantly higher in LPS-stimulated PBMCs Therefore, the chicken's endotoxin response can be assessed by evaluating the pro-inflammatory cytokine production from PBMCs.

Pro-inflammatory cytokine release from chicken peripheral blood mononuclear cells stimulated with lipopolysaccharide

Background and Aim:

The principal cytokines released by the host on infection include pro-inflammatory cytokines such as interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF). These cytokines were regarded as regulators of the host’s response to infection. This study aimed to determine the release of pro-inflammatory cytokines from chicken peripheral blood mononuclear cells (PBMCs) following lipopolysaccharide (LPS) stimulation.

Materials and Methods:

Blood samples were collected from six Betong chickens. To isolate PBMCs, density gradient centrifugation was utilized. PBMC culture in RPMI1640 with 10% fetal bovine serum was stimulated with various concentrations of LPS (0, 0.01, 0.1, and 1.0 μg/mL). The production of TNF-α, IL-1β, and IL-6 was determined using an enzyme-linked immunosorbent assay.

Results:

When the PBMCs were cultured for 24 h with varying doses of LPS, there was no significant variation in cell viability. TNF-α, IL-1β, and IL-6 levels were measured in Betong chicken PBMC. The release of these cytokines increased considerably as LPS concentration (0.01-1 μg/mL) increased (p<0.05).

Conclusion:

In vitro studies of the chicken immune response, notably the release of pro-inflammatory cytokines, can be conducted using PBMCs obtained from chicken blood.

Three-Dimensional Avian Hematopoietic Stem Cell Cultures as a Model for Studying Disease Pathogenesis

Three-dimensional (3D) cell culture is attracting increasing attention today because it can mimic tissue environments and provide more realistic results than do conventional cell cultures. On the other hand, very little attention has been given to using 3D cell cultures in the field of avian cell biology. Although mimicking the bone marrow niche is a classic challenge of mammalian stem cell research, experiments have never been conducted in poultry on preparing in vitro the bone marrow niche. It is well known, however, that all diseases cause immunosuppression and target immune cells and their development. Hematopoietic stem cells (HSC) reside in the bone marrow and constitute a source for immune cells of lymphoid and myeloid origins. Disease prevention and control in poultry are facing new challenges, such as greater use of alternative breeding systems and expanding production of eggs and chicken meat in developing countries. Moreover, the COVID-19 pandemic will draw greater attention to the importance of disease management in poultry because poultry constitutes a rich source of zoonotic diseases. For these reasons, and because they will lead to a better understanding of disease pathogenesis, in vivo HSC niches for studying disease pathogenesis can be valuable tools for developing more effective disease prevention, diagnosis, and control. The main goal of this review is to summarize knowledge about avian hematopoietic cells, HSC niches, avian immunosuppressive diseases, and isolation of HSC, and the main part of the review is dedicated to using 3D cell cultures and their possible use for studying disease pathogenesis with practical examples. Therefore, this review can serve as a practical guide to support further preparation of 3D avian HSC niches to study the pathogenesis of avian diseases.

Differential responses of chicken monocyte-derived dendritic cells infected with Salmonella Gallinarum and Salmonella Typhimurium

Salmonella enterica serovar Gallinarum is a host-restricted bacterial pathogen that causes a serious systemic disease exclusively in birds of all ages. Salmonella enterica serovar Typhimurium is a host-generalist serovar. Dendritic cells (DCs) are key antigen-presenting cells that play an important part in Salmonella host-restriction. We evaluated the differential response of chicken blood monocyte-derived dendritic cells (chMoDCs) exposed to S. Gallinarum or S. Typhimurium. S. Typhimurium was found to be more invasive while S. Gallinarum was more cytotoxic at the early phase of infection and later showed higher resistance against chMoDCs killing. S. Typhimurium promoted relatively higher upregulation of costimulatory and other immune function genes on chMoDCs in comparison to S. Gallinarum during early phase of infection (6 h) as analyzed by real-time PCR. Both Salmonella serovars strongly upregulated the proinflammatory transcripts, however, quantum was relatively narrower with S. Gallinarum. S. Typhimurium-infected chMoDCs promoted relatively higher proliferation of naïve T-cells in comparison to S. Gallinarum as assessed by mixed lymphocyte reaction. Our findings indicated that host restriction of S. Gallinarum to chicken is linked with its profound ability to interfere the DCs function. Present findings provide a valuable roadmap for future work aimed at improved vaccine strategies against this pathogen.

Two Sides to Every Question: Attempts to Activate Chicken Innate Immunity in 2D and 3D Hepatic Cell Cultures

The liver with resident tissue macrophages is the site of vivid innate immunity, activated also by pathogen-associated molecular patterns (PAMPs) leaking through the intestinal barrier. As gut-derived inflammatory diseases are of outstanding importance in broiler chickens, the present study aimed to establish a proper hepatic inflammatory model by comparing the action of different PAMPs from poultry pathogens on chicken 2D and 3D primary hepatocyte—non-parenchymal cell co-cultures, the latter newly developed with a magnetic bioprinting method. The cultures were challenged by the bacterial endotoxins lipopolysaccharide (LPS) from Escherichia coli, lipoteichoic acid (LTA) from Staphylococcus aureus and by enterotoxin (ETxB) from Escherichia coli, Salmonella Typhimurium derived flagellin, phorbol myristate acetate (PMA) as a model proinflammatory agent and polyinosinic polycytidylic acid (poly I:C) for mimicking viral RNA exposure. Cellular metabolic activity was assessed with the CCK-8 test, membrane damage was monitored with the lactate dehydrogenase (LDH) leakage assay and interleukin-6 and -8 (Il-6 and -8) concentrations were measured in cell culture medium with a chicken specific ELISA. Both LPS and LTA increased the metabolic activity of the 3D cultures, concomitantly decreasing the LDH leakage, while in 2D cultures ETxB stimulated, PMA and poly I:C depressed the metabolic activity. Based on the moderately increased extracellular LDH activity, LTA seemed to diminish cell membrane integrity in 2D and poly I:C in both cell culture models. The applied endotoxins remarkably reduced the IL-8 release of 3D cultured cells, suggesting the effective metabolic adaptation and the presumably initiated anti-inflammatory mechanisms of the 3D spheroids. Notwithstanding that the IL-6 and IL-8 production of 2D cells was mostly not influenced by the endotoxins used, only the higher LTA dose was capable to evoke an IL-8 surge. Flagellin, PMA and poly I:C exerted proinflammatory action in certain concentrations in both 2D and 3D cultures, reflected by the increased cellular IL-6 release. Based on these data, LTA, flagellin, PMA and poly I:C can be considered as potent candidates to induce inflammation in chicken primary hepatic cell cultures, while LPS failed to trigger proinflammatory cytokine production, suggesting the relatively high tolerance of avian liver cells to certain bacterial endotoxins. These results substantiate that the established 3D co-cultures seemed to be proper tools for testing potential proinflammatory molecules; however, the remarkable differences between 2D and 3D models should be addressed and further studied.

Visfatin Regulates Inflammatory Mediators in Mouse Intestinal Mucosa Through Toll-Like Receptors Signaling Under Lipopolysaccharide Stress

Visfatin is a multifunctional protein involved in inflammatory immune stress. The aim of current study was to explore the role of visfatin in lipopolysaccharide (LPS)-induced intestinal mucosal inflammation and to confirm its cellular effect in inflammatory immune response through silencing of Toll-like receptors (TLRs). We divided Kunming mice into three groups: Saline group, LPS group, and LPS + visfatin group and performed hematoxylin and eosin staining, immunohistochemistry, quantitative polymerase chain reaction, Western blot, enzyme linked immunosorbent assay and RNA-seq analysis. Pretreatment of visfatin improves LPS-stimulated reduction of tight junction protein 1 (ZO-1) and secretory immunoglobulin A, inhibits overexpression of Claudin-1 and vascular endothelial growth factor, and reduces intestinal mucosal damage and inflammation. RNA-seq analysis of cellular transcriptomes indicated that visfatin is involved in down-regulation of mRNA level of TLR4 as well as attenuation of protein levels of TLR8 and nucleotide-binding oligomerization domain-containing protein 2, revealing that visfatin could reduce intestinal mucosal inflammation through TLR signaling pathway in mice ileum. In RAW264.7 cells, the genes silencing of Toll/IL-1R family, such as TLR4, TLR2, and IL-1R1, was accompanied by decreased expressions of inflammatory factors (TNF-α, IL-1β, IL-6 and MCP-1) along with lower cellular visfatin levels. Hence, visfatin maintains the intestinal mucosal barrier structure and attenuates the intestinal mucosal inflammation through the TLR signaling pathway. Likewise, the Toll/IL-1R family regulates the release of visfatin, which can participate in the inflammatory reaction through the regulation of inflammatory factors.

Elicitation of Highly Pathogenic Avian Influenza H5N1 M2e and HA2-Specific Humoral and Cell-Mediated Immune Response in Chicken Following Immunization With Recombinant M2e-HA2 Fusion Protein

The study was aimed to evaluate the elicitation of highly pathogenic avian influenza (HPAI) virus (AIV) M2e and HA2-specific immunity in chicken to develop broad protective influenza vaccine against HPAI H5N1. Based on the analysis of Indian AIV H5N1 sequences, the conserved regions of extracellular domain of M2 protein (M2e) and HA2 were identified. Synthetic gene construct coding for M2e and two immunodominant HA2 conserved regions was designed and synthesized after codon optimization. The fusion recombinant protein (~38 kDa) was expressed in a prokaryotic system and characterized by Western blotting with anti-His antibody and anti-AIV polyclonal chicken serum. The M2e–HA2 fusion protein was found to be highly reactive with known AIV-positive and -negative chicken sera by ELISA. Two groups of specific pathogen-free (SPF) chickens were immunized (i/m) with M2e synthetic peptide and M2e–HA2 recombinant protein along with one control group with booster on the 14th day and 28th day with the same dose and route. Pre-immunization sera and whole blood were collected on day 0 followed by 3, 7, 14, 21, and 28 days and 2 weeks after the second booster (42 day). Lymphocyte proliferation assay by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) method revealed that the stimulation index (SI) was increased gradually from days 0 to 14 in the immunized group (p < 0.05) than that in control chicken. Toll-like receptor (TLR) mRNA analysis by RT-qPCR showed maximum upregulation in the M2e–HA2-vaccinated group compared to M2e- and sham-vaccinated groups. M2e–HA2 recombinant protein-based indirect ELISA revealed that M2e–HA2 recombinant fusion protein has induced strong M2e and HA2-specific antibody responses from 7 days post-primary immunization, and then the titer gradually increased after booster dose. Similarly, M2e peptide ELISA revealed that M2e–HA2 recombinant fusion protein elicited M2e-specific antibody from day 14 onward. In contrast, no antibody response was detected in the chicken immunized with synthetic peptide M2e alone or control group. Findings of this study will be very useful in future development of broad protective H5N1 influenza vaccine targeting M2e and HA2.

Visfatin Exerts Immunotherapeutic Effects in Lipopolysaccharide-Induced Acute Lung Injury in Murine Model

Visfatin acts as a significant regulator of inflammatory cytokines. However, the immunological response and therapeutic effects of visfatin under bacterial stress in murine lung tissue are still not clear. To investigate the role of visfatin on lipopolysaccharide (LPS)-induced acute lung injury (ALI), thirty Kunming mice were divided into Saline, LPS, and LPS + visfatin groups. After routine blood examination, the effects of visfatin on inflammatory cytokines, lung tissue structure, and expression of inflammatory mediators were explored through hematoxylin-eosin (H&E), Masson and immunohistochemical staining, quantitative polymerase chain reaction (Q-PCR), and Western blotting. Compared with the Saline group, neutrophil percentage, peripheral blood neutrophil count, and the ratio of lymphocyte count (NLR) were upregulated in LPS group. Moreover, Masson staining showed alterations in lung tissue structure; the mRNA level of different cytokines (IL-6, IL-1β, TNF-α, IL-10, TLR4, IFN-γ) was upregulated; and the protein expression of interleukin (IL)-6, myeloperoxidase (MPO), and transforming growth factor-β1 (TGF-β) was significantly (p < 0.05) different in LPS group. Compared with LPS group, neutrophil percentage significantly decreased (p < 0.01), the numbers of lymphocytes significantly (p < 0.05) increased, NLR decreased, Masson staining of the lung was extremely different (p < 0.01), the structure of the lung was slightly damaged, and the myeloperoxidase values of lung showed no differences in LPS + visfatin. Hence, visfatin inhibits the lung inflammation induced by ALI. During the ALI, visfatin acts by decreasing NLR, downregulated the expression of MPO, enhanced antioxidant capacity, and regulated the inflammatory factors IL-1β, IL-6, IL-10, and TNF-α to reduce the lung injury.

In vitro effects of 5 recombinant antigens of Eimeria maxima on maturation, differentiation, and immunogenic functions of dendritic cells derived from chicken spleen

Eimeria maxima possesses integral families of immunogenic constituents that promote differentiation of immune cells during host-parasite interactions. Dendritic cells (DCs) have an irreplaceable role in the modulation of the host immunity. However, the selection of superlative antigen with immune stimulatory efficacies on host DCs is lacking. In this study, 5 recombinant proteins of E. maxima (Em), including Em14-3-3, rhomboid family domain containing proteins (ROM) EmROM1 and EmROM2, microneme protein 2 (EmMIC2), and Em8 were identified to stimulate chicken splenic derived DCs in vitro. The cultured populations were incubated with recombinant proteins, and typical morphologies of stimulated DCs were obtained. DC-associated markers major histocompatibility complex class II, CD86, CD11c, and CD1.1, showed upregulatory expressions by flow cytometry assay. Immunofluorescence assay revealed that recombinant proteins could bind with the surface of chicken splenic derived DCs. Moreover, quantitative real-time PCR results showed that distinct gene expressions of Toll-like receptors and Wnt signaling pathway were upregulated after the coincubation of recombinant proteins with DCs. The ELISA results indicated that the DCs produced a significant higher level of interleukin (IL)-12 and interferon-γ secretions after incubation with recombinant proteins. While transforming growth factor-β was significantly increased with rEmROM1, rEmROM2, and rEmMIC2 as compared to control groups, and IL-10 did not show significant alteration. Taken together, these results concluded that among 5 potential recombinant antigens, rEm14-3-3 could promote immunogenic functions of chicken splenic derived DCs more efficiently, which might represent an effective molecule for inducing the host Th1-mediated immune response against Eimeria infection.

Hizikia fusiforme extract enhances dendritic cell maturation in vitro and in vivo

Dendritic cells (DCs) are play critical roles in the priming and regulation of immune responses. DCs rapidly process and convey these antigens to prime antigen-specific T cells. Therefore, regulation of DCs functions is important for immunity and immunotherapies. Immune adjuvants for DCs activation are needed to improve the efficacy of vaccines against tumors and many infectious diseases. Therefore, we demonstrate that H. fusiformis extract can regulate DCs maturation and activation. H. fusiformis extract induced costimulatory molecules (CD 80 and CD86), antigen-presenting molecules (major histocompatibility complex (MHC) I and II), CCR7 expression, and interleukin (IL)-12 production in DCs. These effects are associated with upregulation of mitogen-activated protein kinase (MAPK) signaling pathway. In addition, H. fusiformis extract induces costimulatory molecules on splenic DCs and activated CD8+ T cells in vivo. Taken together, these findings suggest that H. fusiformis extract may be a potential efficient immune therapeutic compound in DCs-mediated immunotherapies.

ABBREVIATIONS

CTL: cytotoxic T lymphocytes; DCs: dendritic cells; ERK: extracellular signal-regulated kinases; IL: interleukini; JNK: c-Jun N-terminal kinase; MAPK: mitogen-activated protein kinase; MHC: major histocompatibility complex.

Training of Primary Chicken Monocytes Results in Enhanced Pro-Inflammatory Responses

Beta-glucan-stimulated mammalian myeloid cells, such as macrophages, show an increased responsiveness to secondary stimulation in a nonspecific manner. This phenomenon is known as trained innate immunity and is important to prevent reinfections. Trained innate immunity seems to be an evolutionary conserved phenomenon among plants, invertebrates and mammalian species. Our study aimed to explore the training of primary chicken monocytes. We hypothesized that primary chicken monocytes, similar to their mammalian counterparts, can be trained with β-glucan resulting in increased responses of these cells to a secondary stimulus. Primary blood monocytes of white leghorn chickens were primary stimulated with β-glucan microparticulates (M-βG), lipopolysaccharide (LPS), recombinant chicken interleukin-4 (IL-4) or combinations of these components for 48 h. On day 6, the primary stimulated cells were secondary stimulated with LPS. Nitric oxide (NO) production levels were measured as an indicator of pro-inflammatory activity. In addition, the cells were analyzed by flow cytometry to characterize the population of trained cells and to investigate the expression of surface markers associated with activation. After the secondary LPS stimulation, surface expression of colony stimulating factor 1 receptor (CSF1R) and the activation markers CD40 and major histocompatibility complex class II (MHC-II) was higher on macrophages that were trained with a combination of M-βG and IL-4 compared to unstimulated cells. This increased expression was paralleled by enhanced NO production. In conclusion, this study showed that trained innate immunity can be induced in primary chicken monocytes with β-glucan, which is in line with previous experiments in mammalian species. Innate immune training may have the potential to improve health and vaccination strategies within the poultry sector.

FOXP3, CD208, and CD206 Expression in Canine Cutaneous Histiocytoma

Canine cutaneous histiocytoma (CCH) is a noninfectious tumor that spontaneously regresses. It is suggested that this regression is due to tumor cell maturation, which is responsible for CD8 lymphocyte activation and tumor cell destruction. Nevertheless, the possible role of the immune microenvironment in tumor regression has not been investigated to date. The aim of this study was to investigate the expression of CD208 and FoxP3 as markers of dendritic cells and regulatory T lymphocytes, respectively, and tumor cell expression of CD206 as a marker of Langerhans cell activation, and relate these parameters to the different phases of CCH and to intratumoral T cell infiltration. Formalin-fixed, paraffin-embedded samples from 31 CCH were evaluated. In each case, the mitotic count and regression phase were recorded. Within the tumor, a quantitative evaluation of immunolabeled CD208⁺ cells, FoxP3⁺ cells, and CD3⁺ lymphocytes was performed, as well as the CD206⁺ tumor cell location. Intratumoral CD208⁺ cells correlated with CD3⁺ lymphocytic infiltration. The possible role of dendritic cells in tumor regression was not confirmed since CD208 seemed to be a nonspecific marker for canine dendritic cells. FoxP3⁺ lymphocyte density was not correlated with any parameter. Neoplastic Langerhans cells presented progressive CD206 expression, from the bottom of the tumor to the epidermis, which correlated with the tumor regression phase and with intratumoral T lymphocyte infiltration. In conclusion, we confirmed a CD206 phenotype change in tumor cells in a spatial group-related pattern, supporting the hypothesis that tumoral Langerhans cells acquire a mature phenotype with tumor regression.

Immunomodulation of Avian Dendritic Cells under the Induction of Prebiotics

Simple Summary

Dendritic cells recognize pathogen-associated molecular patterns in chicken intestines and are part of the initial immune response. The immunoregulatory properties of prebiotics acting in several ways in poultry have been known for many years. According to their function, dendritic cells should play an indispensable role in the proven effects of prebiotics on the intestinal immune system, such as through activation of T and B cells and cytokine production. Currently, there are no studies concerning direct interactions in poultry between non-digestible feed components and dendritic cells. Whereas most in vitro experiments with chicken dendritic cells have studied their interactions with pathogens, in vitro studies are now needed to determine the impacts of prebiotics on the gastrointestinal dendritic cells themselves. The present lack of information in this area limits the development of effective feed additives for poultry production. The main purpose of this review is to explore ideas regarding potential mechanisms by which dendritic cells might harmonize the immune response after prebiotic supplementation and thereby provide a basis for future studies.

Abstract

Although the immunomodulatory properties of prebiotics were demonstrated many years ago in poultry, not all mechanisms of action are yet clear. Dendritic cells (DCs) are the main antigen-presenting cells orchestrating the immune response in the chicken gastrointestinal tract, and they are the first line of defense in the immune response. Despite the crucial role of DCs in prebiotic immunomodulatory properties, information is lacking about interaction between prebiotics and DCs in an avian model. Mannan-oligosaccharides, β-glucans, fructooligosaccharides, and chitosan-oligosaccharides are the main groups of prebiotics having immunomodulatory properties. Because pathogen-associated molecular patterns on these prebiotics are recognized by many receptors of DCs, prebiotics can mimic activation of DCs by pathogens. Short-chain fatty acids are products of prebiotic fermentation by microbiota, and their anti-inflammatory properties have also been demonstrated in DCs. This review summarizes current knowledge about avian DCs in the gastrointestinal tract, and for the first-time, their role in the immunomodulatory properties of prebiotics within an avian model.

Current knowledge about interactions between avian dendritic cells and poultry pathogens

In poultry production conditions today, birds are surrounded by viral, bacterial, and parasitic agents. DCs are the main antigen-presenting cells located in tissues of the body, and their role involves recognizing antigen structures, engulfing and processing them, and subsequently presenting antigen peptides on their surface by major histocompatibility complex, where T cells and B cells are stimulated and can begin appropriate cellular and antibody immune response. This unique function indicates that these cells can be used in producing vaccines, but first it is necessary to culture DCs in vitro to identify the principles of their interactions with pathogens. The following review summarizes our current knowledge about avian dendritic cells and their interactions with pathogens. It provides a basis for future studies of these unique cells and their use in vaccine development.

Unravelling fatty liver haemorrhagic syndrome: 2. Inflammation and pathophysiology

To study the role of inflammation in the pathophysiology of the fatty liver haemorrhagic syndrome (FLHS), mature laying hens were treated with oestrogen (β-oestradiol-17-dipropionate or E₂) and challenged with lipopolysaccharide (LPS). Oestrogen injections induced FLHS, but the incidence and severity of the condition was increased with a combination of E₂ & LPS. Hepatic mRNA levels of the genes encoding key regulators of inflammation, such as interleukin-1β (IL-1β), interleukin-6 (IL-6) and interleukin-18 (IL-18), were evaluated. The expression of IL-6 mRNA in hepatocytes of all treated groups (E₂, LPS and E₂ & LPS hens) was elevated from 6-fold to 56-fold (P < 0.01), when compared to baseline and control values, with the highest fold change at 3 h post-treatment. The mRNA levels for IL-1β were better expressed at 24 h post-treatments with E₂, LPS and E₂ & LPS. The expression of IL-18 mRNA in the liver tissue was lower than IL-1β and IL-6 mRNA in all treated birds. At 24 h post-treatment, total white blood cell (WBC) counts and fibrinogen levels were elevated (P < 0.05) in E₂-, LPS- and E₂- & LPS-treated hens. Histologically, livers of hens from E₂- and E₂- & LPS-treated groups revealed inflammatory alterations with areas showing mononuclear aggregations, vacuolar fatty degeneration of hepatocytes, and increased sinusoidal congestion and haemorrhages. It was concluded that liver lipid accumulation and injury were associated with incidences of local (hepatic) and systemic inflammation, which could have initiated liver blood vessel and capsule rupture and, subsequently, the onset of FLHS.

Repeated stimulation by LPS promotes the senescence of DPSCs via TLR4/MyD88-NF-κB-p53/p21 signaling

Dental pulp stem cells (DPSCs), one type of mesenchymal stem cells, are considered to be a type of tool cells for regenerative medicine and tissue engineering. Our previous studies found that the stimulation with lipopolysaccharide (LPS) might introduce senescence of DPSCs, and this senescence would have a positive correlation with the concentration of LPS. The β-galactosidase (SA-β-gal) staining was used to evaluate the senescence of DPSCs and immunofluorescence to show the morphology of DPSCs. Our findings suggested that the activity of SA-β-gal has increased after repeated stimulation with LPS and the morphology of DPSCs has changed with the stimulation with LPS. We also found that LPS bound to the Toll-like receptor 4 (TLR4)/myeloid differentiation factor (MyD) 88 signaling pathway. Protein and mRNA expression of TLR4, MyD88 were enhanced in DPSCs with LPS stimulation, resulting in the activation of nuclear factor-κB (NF-κB) signaling, which exhibited the expression of p65 improved in the nucleus while the decreasing of IκB-α. Simultaneously, the expression of p53 and p21, the downstream proteins of the NF-κB signaling, has increased. In summary, DPSCs tend to undergo senescence after repeated stimulation in an inflammatory microenvironment. Ultimately, these findings may lead to a new direction for cell-based therapy in oral diseases and other regenerative medicines.

SIRT1 regulates lipopolysaccharide-induced CD40 expression in renal medullary collecting duct cells by suppressing the TLR4-NF-κB signaling pathway

AIMS

Recent evidence indicates that sirtuin1 (SIRT1), an NAD⁺-dependent deacetylase, exerts a protective effect against inflammatory kidney injury by suppressing pro-inflammatory cytokines production. The co-stimulatory molecule, CD40, is expressed in a variety of inflammatory diseases in the kidney. Here, we aimed to investigate the potential effect of SIRT1 on CD40 expression induced by lipopolysaccharide (LPS) and to disclose the underlying mechanisms in renal inner medullary collecting duct (IMCD) cells.

MAIN METHODS

mRNA and protein expressions were identified by quantitative real-time PCR and Western blot respectively. Subcellular localization of SIRT1 and CD40 were respectively detected by immunofluorescence and immunohistochemical staining. Small-interfering RNA (siRNA) was carried out for mechanism study.

KEY FINDINGS

LPS reduced SIRT1 expression and up-regulated the expression of CD40, Toll-like receptor 4 (TLR4) and phospho-NF-κBp65 (p-NF-κBp65) in time- and concentration-dependent manners. Moreover, SIRT1 overexpression or activation by SRT1720 diminished the expression of CD40, TLR4 and p-NF-κBp65, which was reversed by SIRT1 siRNA or inhibitors Ex527 and sirtinol in LPS-stimulated IMCD cells. In addition, knockdown of TLR4 decreased the expression of CD40 and p-NF-κBp65 in IMCD cells exposed to LPS. Knockdown of NF-κBp65 or NF-κBp65 inhibition by pyrrolidine dithiocarbamate (PDTC) reduced LPS-induced CD40 expression in IMCD cells. Importantly, the inhibitory effect of SIRT1 on the expression of CD40 and p-NF-κBp65 was augmented by pre-treating with TLR4 siRNA.

SIGNIFICANCE

Our data indicate that SIRT1 inhibits LPS-induced CD40 expression in IMCD cells by suppressing the TLR4-NF-κB signaling pathway, which might provide novel insight into understanding the protective effect of SIRT1 in kidney.