Immunosuppression participated in complement activation-mediated inflammatory injury caused by 4-octylphenol via TLR7/IκBα/NF-κB pathway in common carp (Cyprinus carpio) gills.

4-octylphenol (4-OP), a toxic estrogenic environmental pollutant, can threaten aquatic animal and human health. However, toxic effect of 4-OP on fish has not been reported. To investigate molecular mechanism of gill poisoning caused by 4-OP exposure, a carp 4-OP poisoning model was established, and then blood and gills were collected on day 60. The results demonstrated that gill was a target organ attacked by 4-OP, and exposure to 4-OP caused carp gill inflammatory injury. There were 1605 differentially expressed genes (DEGs, including 898 up-regulated DEGs and 707 down-regulated DEGs). KEGG and GO were used to further analyze obtained 1605 DEGs, indicating that complement activation, immune response, and inflammatory response participated in the mechanism of 4-OP-caused carp gill inflammatory injury. Our data at transcription level further revealed that 4-OP caused complement activation through triggering complement component 3a/complement component 3a receptor (C3a/C3aR) axis and complement component 5a/complement component 5a receptor 1 (C5a/C5aR1) axis, induced immunosuppression through the imbalances of T helper (Th) 1/Th2 cells and regulatory T (Treg)/Th17 cells, as well as caused inflammatory injury via toll like receptor 7/inhibitor kappa B alpha/nuclear factor-kappa B (TLR7/IκBα/NF-κB) pathway. Taken together, immunosuppression participated in complement activation-mediated inflammatory damage in carp gills after 4-OP treatment. The findings of this study will provide pioneering information and theoretical support for the mechanism of 4-OP poisoning, and will provide reference for the assessment of estrogenic environmental pollution risk.

The involvement of miR-6615-5p/Smad7 axis and immune imbalance in ammonia-caused inflammatory injury via NF-κB pathway in broiler kidneys.

Ammonia (NH3), a toxic gas, has deleterious effects on chicken health in intensive poultry houses. MicroRNA can mediate inflammation. The complex molecular mechanisms underlying NH3 inhalation-caused inflammation in animal kidneys are still unknown. To explore the mechanisms, a broiler model of NH3 exposure was established. Kidney samples were collected on day 14, 28, and 42, and meat yield was evaluated on day 42. We performed histopathological examination, detected miR-6615-5p and mothers against decapentaplegic homolog 7 (Smad7), and determined inflammatory factors and cytokines in kidneys. The results showed that excess NH3 reduced breast weight and thigh weight, which indicated that excess NH3 impaired meat yield of broilers. Besides, kidney tissues displayed histopathological changes after NH3 exposure. Meanwhile, the increases of inducible nitric oxide synthase (iNOS) activity and nitric oxide content were obtained. The mRNA and protein expression of inflammatory factors, including nuclear factor-κB (NF-κB), cyclooxygenase-2, prostaglandin E synthases, and iNOS increased, indicating that NF-κB pathway was activated. T-helper (Th) 1 and regulatory T (Treg) cytokines were downregulated, whereas Th2 and Th17 cytokines were upregulated, suggesting the occurrence of Th1/Th2 and Treg/Th17 imbalances. In addition, we found that Smad7 was a target gene of miR-6615-5p in chickens. After NH3 exposure, miR-6615-5p expression was elevated, and Smad7 mRNA and protein expression were reduced. In summary, our results suggest that NH3 exposure negatively affected meat yield; and miR-6615/Smad7 axis and immune imbalance participated in NH3-induced inflammatory injury via the NF-κB pathway in broiler kidneys. This study is helpful to understand the mechanism of NH3-induced kidney injury and is meaningful to poultry health and breed aquatics.

Whole transcriptome-based miRNA-mRNA network analysis revealed the mechanism of inflammation-immunosuppressive damage caused by cadmium in common carp spleens.

Cadmium (Cd) is a well-known environmental pollutant and can damage fish. MicroRNAs (miRNAs) can involve in inflammation and immunosuppression. However, the mechanisms of miRNAs are still unclear in common carp (Cyprinus carpio L.) treated by Cd. In current study, 54 juvenile common carp were randomly divided into the control group and the Cd group (0.26 mg L-1 Cd) and were cultured for 30 days. The results revealed inflammatory damage in the spleens of common carp after Cd exposure using morphological construction. There were 23 differentially expressed miRNAs including 17 up-regulated differentially expressed miRNAs (miR-1-4-3p, miR-7-1-5p, miR-7-2-5p, miR-10-43-5p, miR-34-3-5p, miR-128-4-3p, miR-128-5-3p, miR-132-2-5p, miR-132-6-5p, miR-216-3-5p, miR-216-4-5p, miR-375-2-3p, miR-375-4-3p, miR-375-5-3p, miR-375-7-3p, miR-375-8-3p, and miR-724-5p) and 6 down-regulated differentially expressed miRNAs (miR-9-6-5p, miR-25-9-3p, miR-31-3-5p, miR-31-12-5p, miR-103-5-5p, and miR-122-1-3p). The 23 miRNAs regulated 2022 target mRNAs. There were 10 pathways and 9 annotation clusters on 2022 target mRNAs using KEGG and GO analysis, respectively. Among them, 5 pathways (NF-κB signaling pathway, Jak-STAT signaling pathway, MAPK signaling pathway, Th1 and Th2 cell differentiation, and Toll-like receptor signaling pathway) and 7 GO terms (negative regulation of immune system process, T cell mediated immunity, regulation of immune response, inflammatory response, positive regulation of inflammatory response, regulation of inflammatory response, and inflammasome complex) were associated with inflammatory response and immunosuppression. miR-375-4-3p, NF-κB, COX-2, PTGES, and IL-4/13A increased and miR-31-12-5p, miR-9-6-5p, MMP9, IL-11, SPI1, and T-Bet decreased using transcriptome sequencing and RT-qPCR in Cd-treated common carp spleens, which revealed that our results were reliable. Our data indicated that miRNAs mediated inflammation-immunosuppressive injury caused by Cd in common carp spleens using whole transcriptome-based miRNA-mRNA network analysis. Our study provided new insights into the toxicology of Cd exposure.

Selenium alleviates oxidative stress and autophagy in lead-treated chicken testes.

Lead (Pb) is an environmental pollutant and has toxic effect on birds. Selenium (Se) has alleviative effect on Pb poisoning. This study investigated mitigative effect of Se on autophagy in Pb-treated chicken testes. Seven-day-old male chickens were randomly divided into four groups with 45 birds in each group. The birds of the control group were offered drinking water (DW) and commercial diet (CD) (0.49 mg/kg Se). The birds of the Se group were offered DW and CD containing sodium selenite (SeCD) (1.00 mg/kg Se). The birds of the Pb group were offered DW containing lead acetate (PbDW) (350.00 mg/L Pb) and CD. The birds of the Pb/Se group were offered PbDW and SeCD. On the 30th, 60th, and 90th days, respectively; histology, antioxidant indexes (hydrogen peroxide (H2O2), catalase (CAT), total antioxidant capacity (TAOC), reduced glutathione (GSH), and superoxide dismutase (SOD)), mRNA and protein levels of autophagy-related genes (autophagy-related proteins 5, Beclin 1, Dynein, light chain 3 (LC3)-I, LC3-II, and mammalian target of rapamycin (mTOR)) were performed in chicken testes. The results of this study showed that Pb caused histological changes; increased H2O2 content; decreased CAT, TAOC, and SOD activities and GSH content; and increased mRNA and protein levels of the above autophagy-related genes except that mTOR decreased in chicken testes. Se alleviated the above changes. Se alleviated histological damage, oxidative stress, and autophagy in the Pb-treated chicken testes.

Alleviation of lead-induced oxidative stress and immune damage by selenium in chicken bursa of Fabricius.

We investigated lead (Pb)-induced oxidative stress and immune damage in the chicken bursa of Fabricius (BF) and the ameliorative effect of selenium (Se). Seven-day-old male chickens were randomly divided into four groups and were provided standard diet and drinking water, Na2SeO3 added to the standard diet and drinking water, standard diet and (CH3COO)2Pb added to drinking water, and Na2SeO3 added to the standard diet and (CH3COO)2Pb added to drinking water for 30, 60, and 90 days. The presence of Pb inhibited total antioxidant capacity (T-AOC), glutathione peroxidase (GPx), glutathione S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT) activities; decreased glutathione (GSH) content; increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents; inhibited interleukin (IL)-2 and interferon-γ (IFN-γ) messenger RNA (mRNA) expression; and increased IL-4, IL-6, IL-10, IL-12ß, and IL-17 mRNA expression. The presence of Se relieved all of the above Pb-induced changes. There were close correlations among GSH, CAT, T-AOC, SOD, GPx, MDA, and H2O2 and among IL-2, IL-4, IL-6, IL-12ß, IL-17, and IFN-γ. Our data showed that Pb caused oxidative stress and immune damage in the chicken BF. Se alleviated Pb-induced oxidative stress and immune damage in the chicken BF.

Toxicological Effect of Manganese on NF-κB/iNOS-COX-2 Signaling Pathway in Chicken Testes.

Manganese (Mn) pollution can cause tissue and organ dysfunction and structural damage. The toxicity of Mn in poultry was reported, but inflammatory damage that Mn induced in the testicular tissue has not been reported. The aim of this study was to investigate the effect of Mn poisoning on NF-κB/iNOS-COX-2 signaling pathway in chicken testes. One hundred eighty Hyline male chickens at 7 days of age were fed either commercial diet or MnCl2-added commercial diet containing 600, 900, and 1800 mg/kg Mn for 30, 60, and 90 days, respectively. The messenger RNA (mRNA) expression of nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS), nitric oxide (NO) content, iNOS activity, and histopathology were examined in chicken testes. The results showed that excess Mn upregulated mRNA expression of NF-κB, COX-2, TNF-α, and iNOS, NO content, and iNOS activity at 60th and 90th day. Mn had a time-dependent effect on NF-κB and TNF-α mRNA expression. Mn had a dose- and time-dependent effect on NO content and iNOS activity. Mn exposure induced chicken testis histological changes in dose- and time-dependent manner. It indicated that Mn exposure resulted in inflammatory injury of chicken testis tissue through NF-κB/iNOS-COX-2 signaling pathway.