Salmonella Pullorum effector SteE regulates Th1/Th2 cytokine expression by triggering the STAT3/SOCS3 pathway that suppresses NF-κB activation

Salmonella enterica serovar Pullorum (S. Pullorum) can regulate host immunity via special effectors that promote persistent infection and its intracellular survival. SteE as an anti-inflammatory effector is involved in the systemic infection of Salmonella in host macrophages. Macrophage activation can indirectly reflect the immune regulatory function of T helper type 1 (Th1)/T helper type 2 (Th2) cytokines. However, information concerning the regulation of Th1/Th2 cytokine expression by steE in S. Pullorum infection is limited. This study evaluates the effects of steE on the Th1/Th2 balance, STAT3/SOCS3 pathway, and NF-κB P65 activation in S. Pullorum-infected HD-11 cells and in chicken models. We demonstrated that steE diminished the expression of Th1-related cytokines (IFN-γ and IL-12) and promoted the expression of Th2-related cytokines (IL-4 and IL-10) in HD-11 cells and chicken models of S. Pullorum infection. SOCS3 silencing suppressed the function of steE in HD-11 cells and led to the imbalance of Th1/Th2-related cytokines. SteE promoted SOCS3 expression by activating STAT3 in HD-11 cells. Moreover, steE inhibited NF-κB P65 expression and blocked its translocation to the nucleus by promoting SOCS3 expression. Our results illustrated that steE regulated the expression of Th1/Th2 cytokines via modulation of the STAT3/SOCS3 and NF-κB axis, which might be associated with Th1/Th2 cell differentiation and could, therefore, be a novel therapeutic strategy against salmonellosis.

Oil-based contrast for hysterosalpingography-regulated Th1/Th2-type cytokines and alleviated inflammation in rats with LPS-induced chronic endometritis

AIM

The chronic endometritis (CE) prevalence in people experiencing infertility is 2.8-56.8%, pregnancy rates in patients with infertility increase after hysterosalpingography with oil-based contrast, but the effect and mechanism are not clear. Here, we analyzed the effects of intrauterine ethiodized poppyseed oil (EPO) bathing on a rat model of CE and the possible underlying mechanism.

METHODS

CE rats were induced by lipopolysaccharide (LPS) exposure, and rats were subjected to intrauterine bathing with EPO or phosphate-buffered saline (PBS) after model verification. Serum and uterus levels of IFN-γ, IL-4, TNF-α, and IL-1β were detected by ELISA kit, and the number of CD138⁺ and CD68⁺ cells and uterine IFN-γ, IL-4, TNF-α, IL-1β, and NF-κB P65 expression were detected by immunohistochemistry after bathing.

RESULTS

LPS exposure induced the typical CE phenotype with CD138⁺ phagocyte infiltration of the endometrial stroma. Compared with PBS bathing, bathing with EPO in CE rats showed decreases in the CD138⁺ and CD68⁺ cells populations and significant decreases in serum and uterine IFN-γ levels, moreover, uterine IL-4 levels were slightly higher, and the IFN-γ/IL-4(Th1/Th2-type cytokine ratio) in the uterus was significantly lower. Local IFN-γ, TNF-α, and NF-κB P65 expression in the endometrium was significantly downregulated, while IL-4 expression was upregulated.

CONCLUSION

Intrauterine oil-based contrast bathing significantly alleviated local inflammation in the rat CE model by downregulating NF-κB P65 expression, reducing IFN-γ (Th1), increasing IL-4 levels (Th2) in the endometrium, and regulating the Th1/Th2-type cytokine trends toward Th2.

Macrophage-derived exosomal miR-4532 promotes endothelial cells injury by targeting SP1 and NF-κB P65 signalling activation

Atherosclerosis is a complex pathological process involving macrophages, endothelial cells and vascular smooth muscle cells that can lead to ischemic heart disease; however, the mechanisms underlying cell‐to‐cell communication in atherosclerosis are poorly understood. In this study, we focused on the role of exosomal miRNAs in crosstalk between macrophages and endothelial cells and explored the rarely studied molecular mechanisms involved. Our in vitro result showed that macrophage‐derived exosomal miR‐4532 significantly disrupted human umbilical vein endothelial cells (HUVECs) function by targeting SP1 and downstream NF‐κB P65 activation. In turn, increased endothelin‐1 (ET‐1), intercellular cell adhesion molecule‐1 (ICAM‐1) and vascular cell adhesion molecule‐1 (VCAM‐1) and decreased endothelial nitric oxide synthase (eNOS) expression in HUVECs increased attraction of macrophages, exacerbating foam cell formation and transfer of exosomal miR‐4532 to HUVECs. MiR‐4532 overexpression significantly promoted endothelial injury and pretreatment with an inhibitor of miR‐4532 or GW4869 (exosome inhibitor) could reverse this injury. In conclusion, our data reveal that exosomes have a critical role in crosstalk between HUVECs and macrophages. Further, exosomal miR‐4532 transferred from macrophages to HUVECs and targeting specificity protein 1 (SP1) may be a novel therapeutic target in patients with atherosclerosis.

[Effects of different extracts of Dendrobium officinale on rats with chronic pharyngitis induced by pepper water combined with ammonia]

Dendrobium officinale can serve as Chinese medicinal material effective in nourishing yin, clearing heat, and producing fluid, and is used to treat throat diseases, but its active substances and mechanism are not clear. To clarify the active fraction and underlying mechanism of D. officinale against chronic pharyngitis(CP), the present study induced a CP model in rats by pepper water combined with low-concentration ammonia, and crude polysaccharides of D. officinale(DOP), non-polysaccharides of D. officinale(DON), and total extract of D. officinale(DOT)(0.33 g·kg~(-1), calculated according to the crude drug) were administered by gavage for six weeks. The changes in oral secretions and pharyngeal conditions of rats with CP were observed and rated. The hematological indicators were determined by an automatic hematology analyzer. The serum levels of pro-inflammatory factors, such as tumor necrosis factor-alpha(TNF-α), interleukin 1β(IL-1β), and interleukin 6(IL-6), and T-lymphocyte cytokines, including interferon γ(IFN-γ), interleukin 4(IL-4), interleukin 17(IL-17), and transforming growth factor β1(TGF-β1) were detected by the enzyme-linked immunosorbent assay(ELISA). The proportions of CD3~+, CD4~+, and CD8~+cells in peripheral blood T lymphocyte subsets were determined by the flow cytometry. The histomorphological changes of the pharynx were observed by hematoxylin-eosin(HE) staining. The protein expression of nuclear factor-κB P65(NF-κB P65), cyclooxygenase-2(COX-2), F4/80, and monocyte chemoattractant protein-1(MCP-1) in the pharynx were detected by immunohistochemistry and Western blot. The results showed that DOP and DON could significantly relieve pharyngeal lesions, reduce white blood cells(WBC) and lymphocytes(LYMP), decrease the levels of pro-inflammatory factors TNF-α, IL-6, and IL-1β, and inhibit the protein expression of NF-κB P65, COX-2, F4/80, and MCP-1 in the pharynx. DOP was superior in reducing oral secretions and serum IL-17 level and inferior in increasing CD4~+/CD8~+ratio to DON. It is suggested that both polysaccharides and non-polysaccharides of D. officinale have anti-PC effects and the anti-inflammatory mechanism may be related to the regulation of T lymphocyte distribution and inhibition of the inflammatory signaling pathways mediated by NF-κB P65. The anti-inflammatory effect of DOP may be related to the regulation of Th17/Treg balance, while that of DON may be related to the regulation of the Th/Tc ratio.

Physcion 8-O-β-glucopyranoside ameliorates liver fibrosis through inflammation inhibition by regulating SIRT3-mediated NF-κB P65 nuclear expression

Physcion 8-O-β-glucopyranoside (PSG), an anthraquinone extracted from Rumex japonicus Houtt, has various pharmacological effects, however, the effect of PSG on liver fibrosis and its related mechanism remain to be determined. We here showed that PSG ameliorated liver injury and liver fibrosis, decreased collagen deposition and inhibited inflammation in carbon tetrachloride (CCl4)-induced rats. Consistent with the in vivo results, PSG suppressed the transforming growth factor-β1 (TGF-β1)-induced cell viability, liver fibrosis and secretion of inflammatory factors in hepatic stellate cells (HSCs). Interestingly, PSG increased the enzyme activity and promoter activity of sirtuin 3 (SIRT3) in fibrotic liver and activated HSCs. In addition, PSG notably increased the mRNA and protein expression of SIRT3 both in vivo and in vitro. Depletion of SIRT3 either by using 3-TYP (SIRT3 selective inhibitor) or SIRT3 siRNA attenuated the anti-inflammatory effect of PSG in activated HSCs. Further study found that TGF-β1 increased the nuclear expression of NF-κB p65, but showed no obvious effect on the total NF-κB p65 expression. Compared to the control adenovirus (Ad.mk), overexpression of SIRT3 by infecting adenovirus encoding SIRT3 (Ad.SIRT3) notably decreased the nuclear expression of NF-κB p65 in activated HSCs. Our results demonstrated that PSG attenuated inflammation by regulating SIRT3-mediated NF-κB P65 nuclear expression in liver fibrosis, providing novel molecular insights into the anti-fibrotic effect of PSG.

[Regulation of Chrysophanol-mediated TLR4/NF-κB Pathway on Renal Injury and Immune Response in IgA Nephropathy Rats]

OBJECTIVE

To investigate the regulatory effect and its mechanism of chrysophanol (CP) on renal injury and immune response in immunoglobin A (IgA) nephropathy rats.

METHODS

IgA nephropathy rat model was established by the method of lipopolysaccharide + bovine serum protein + carbon tetrachloride. Then the rats were randomly divided into 5 groups: control group, IgA group, IgA+low, medium and high dose of CP groups(2.5, 5 and 10 mg/kg for each group respectively). IgA+CP groups were intraperitoneally injected with different doses of chrysophanol once a day for 4 weeks, and the control group and IgA group were given isovolumetric saline. Urine protein content, serum creatinine and urea nitrogen were detected at 24 h after the administration of drugs. Kidney histopathological damage and apoptosis were measured by HE and TUNEL staining. The expression levels of Caspase-3 and Caspase-9 were detected by RT-PCR and Western blot; The contents of malondialdehyde (MDA), superoxide dismutase (SOD) and (glutathione peroxidase, Gpx) were detected by enzyme-linked immunosorbent assay (ELISA). The expression of interleukin-1β, -6 (IL-1β, IL-6) and tumor necrosis factor (TNF-α) in serum and kidney tissue were measured by ELISA and Western blot, respectively. The mRNA and protein expression levels of toll-like receptro 4 (TLR4), nuclear factor-κB P65 (NF-κB P65) were also detected by RT-PCR and Western blot, and vascular cell adherin molecule (VCAM-1) protein level was deteted by Western blot.

RESULTS

In IgA nephropathy rats, the administration of CP reduced proteinuria, serum creatinine and urea nitrogen in a dose-dependent manner (P < 0.01). It also improved the pathological damage of kidney tissue, reduced the apoptosis rate (P < 0.01), and decreased the mRNA and protein expression levels of apoptosis-related proteins Caspase-3 and Caspase-9 (P < 0.01). CP inhibited MDA production while increased the activities of antioxidant enzymes Gpx and SOD (P < 0.01), and decreased the levels of serum and protein expression of IL-1β, IL-6 and TNF-α (P < 0.01), as well as the expression levels of TLR4, NF-κB P65 and VCAM-1 (P < 0.01).

CONCLUSION

Chrysophanol could play a protective role in IgA nephropathy rats, and its mechanism may be related to alleviating kidney injury and regulating immune response.

[LncRNA MALAT1 Modulates the Immunoreaction of Rats with Lipopolysaccharide-induced Sepsis by Targeting the miR-146a/NF-κB P65 Pathway]

OBJECTIVE

To determine the regulatory and molecular mechanism of lncRNA MALAT1 in response to sepsis induced by lipopolysaccharide (LPS) in rats.

METHODS

The expressions of lncRNA MALAT1 and miR-146a in U937 cells and peripheral blood samples of the rats with and without LPS-induced sepsis were detected using quantitative real-time reverse transcription PCR (qRT-PCR). The relationship between lncRNA MALAT1 and miR-146a was affirmed through luciferase assay. The expressions of p-P65, P65, TNF-α and iNOS were tested by Western blot. The expressions of TNF-α and iNOS in the lung tissues of the rats were measured by immunohistochemistry.

RESULTS

The rats with LPS-induced sepsis had higher expressions of lncRNA MALAT1 in U937 cells than those without sepsis (P<0.001). In comparison with scramble, si-MALAT1 attenuated the expression of lncRNA MALAT1 and increased the expression of miR-146a (P<0.001). MiR-146a was the target of lncRNA MALAT1. si-MALAT1 decreased the p-P65/P65 ratio and and the expressions of TNF-α and iNOS in the rats with LPS-induced sepsis. In contrast, miR-146a inhibitor increased p-P65/P65 ratio and the expressions of TNF-α and iNOS in the rats with LPS-induced septis (P<0.001). Co-transfection with si-MALAT1 attenuated the elevated level of p-P65/P65 ratio and expressions of TNF-α and iNOS resulting from miR-146a inhibitor (P<0.001). LPS and scramble decreased the expression of miR-146a and increased the p-P65/P65 ratio compared with the healthy controls (P<0.01). Compared with scramble, si-MALAT1 increased the expression of miR-146a and attenuated the p-P65/P65 ratio (P<0.01). Higher numbers of TNF-α and iNOS positive cells were found in those with LPS-induced sepsis and those with scramble interventions (P<0.001). Compared with scramble, si-MALAT1 reduced the number of TNF-α and iNOS positive cells (P<0.01).

CONCLUSIONS

LncRNA MALAT1 modulates the immunoreaction of rats with LPS -induced sepsis by targeting miR-146a/NF-κB P65.

Astaxanthin alleviated acute lung injury by inhibiting oxidative/nitrative stress and the inflammatory response in mice

The purpose of the present study was to assess the effect of astaxanthin (ASX) treatment on the acute lung injury (ALI) induced by cecal ligation and puncture (CLP) in mice. Mice were randomly allocated into the following groups: (1) the saline control group, in which mice were given saline before sham operation; (2) the ASX control group, in which mice received ASX before sham operation; (3) the ALI group, in which mice were given saline before CLP operation; and (4) the ALI+ASX group, in which mice received ASX before CLP operation. ASX was dissolved in olive oil and administrated by oral gavage for 14days consecutively before the CLP or sham operation. In experiment 1, Kaplan-Meier survival analysis was conducted for 72h after CLP. In experiment 2, blood, bronchoalveolar lavage fluid (BALF) and lung tissues were collected at 24h after the CLP or sham operation to determine the severity of lung injury. The results showed that ASX treatment could significantly decrease the CLP-induced mortality rate in mice. Meanwhile, ASX treatment significantly attenuated CLP-induced lung histopathological injury, inflammatory infiltration, total protein and albumin concentration, and total cell and neutrophil counts in the BALF. Furthermore, ASX treatment alleviated oxidative/nitrative stress, inflammation levels and pulmonary apoptosis in lung tissues. In addition, ASX treatment markedly down-regulated the expression of inducible nitric oxide synthase (i-NOS), nitrotyrosine (NT) and nuclear factor-kappa B (NF-Κb) P65 in the lung tissues compared with that in the ALI group. Astaxanthin treatment had markedly protective effect against ALI in mice, and the potential mechanism is associated with its ability to inhibit the inflammatory response, oxidative/nitrative stress, and pulmonary apoptosis, as well as down-regulate NF-κB P65 expression.

Attenuating effect of Ginsenoside Rb1 on LPS-induced lung injury in rats

BACKGROUND

Sepsis causes neutrophil sequestration in the lung which leads to acute lung injury (ALI). Radix Ginseng (RG), a traditional herb used as herbal remedy in eastern Asia for thousands of years, which has been traditionally used in China to improve blood circulation and ameliorate pathological hemostasis. This study investigated whether Ginsenoside Rb1, the main components of RG, can attenuate ALI induced by LPS.

METHODS

In vivo, 30 male Wistar rats were divided into three groups (n = 10 each groups) on the basis of the reagent used, which were subjected to LPS injection with or without Ginsenoside Rb1 (5 mg/kg) treatments to induce ALI model. Lung injury was assessed by pulmonary histology, lung wet-weight to dry-weight (W/D) ratio, the number of myeloperoxidase (MPO) positive cells, immunohistochemical analysis of intercellular adhesion molecule-1 (ICAM-1), gene expression of ICAM-1, ultrastructure changes of pulmonary microvasculature, concentration of inflammatory markers and in plasma. In vitro, pulmonary microvascular endothelial cells (PMVECs) were stimulated with LPS in the presence and absence of Ginsenoside Rb1 (50 mM), nuclear factor-κB (NF-κB) p65 was measured by immunocytochemistry staining and western blotting.

RESULTS

Infusion of LPS induced lung injury, in vivo, as demonstrated by pulmonary edema with infiltration of neutrophils and hemorrhage, the increase in lung W/D ratio, the number of MPO positive cells, the level of inflammatory markers such as TNF-α, MCP-1 and IL-8, enhanced expression of ICAM-1 and ICAM-1 gene. Moreover, resulted in the changes of intercellular junctions in the endothelial cells of pulmonary microvasculature. In vitro, the significant increased release of NF-κB p65 and its subsequent translocation into the nucleus in PMVECs were observed. In contrast, Ginsenoside Rb1 treatment significantly ameliorated the LPS-induced lung injury, as judged by the marked improvement in all these indices.

CONCLUSIONS

These results indicate that Ginsenoside Rb1 attenuated LPS-induced lung injury through an inhibition of the inflammatory signaling pathway, besides the direct inhibitory effect on proinflammatory molecules.

Treatment with Compound Indigo Granules down-regulates NF-κB P65 and TNF-α expression in ulcerative colitis in rats

AIM: To determine the mechanism underlying the therapeutic effects of Compound Indigo Granules (CIG) against ulcerative colitis by investigating the effect of treatment with CIG on the expression of nuclear factor-κB P65 (NF-κB P65) and tumor necrosis factor (TNF)-α in the colon of rats with experimental ulcerative colitis.

METHODS: Ulcerative colitis was induced in rats with trinitrobenzenesulfonic acid (TNBS). Rats were divided into control group, model group, salazosulfapyridine (SASP) group, low-, medium-, and high-dose CIG groups. Except the control group, the other groups were intragastrically given normal saline, SASP, and different doses of CIG from day 3 after model induction for 10 days, respectively. On day 14, all rats were killed to take colon and serum samples for measuring colonic NF-κB P65 expression by immunohistochemisty and serum TNF-α levels by enzyme-linked immunosorbent assay (ELISA).

RESULTS: The levels of NF-κB P65 protein expression in the colon and serum TNF-α were significantly higher in the model group than in the control group (0.138 ± 0.003 vs 0.276 ± 0.0081; 18.990 ± 3.964 vs 67.657 ± 3.580, both P < 0.05) but were significantly lower in the high-dose CIG group than in the model group (0.217 ± 0.007 vs 0.276 ± 0.008; 27.783 ± 2.867 vs 67.657 ± 3.580, both P < 0.05).

CONCLUSION: Treatment with CIG significantly decreased the levels of NF-κB P65 protein expression in the colon and serum TNF-α in rats with ulcerative colitis. CIG exerts therapeutic effects against ulcerative colitis possibly via mechanisms associated with the NF-κB signaling pathway and down-regulation of TNF-α.