Sheep β-Defensin 2 Regulates Escherichia coli F17 Resistance via NF-κB and MAPK Signaling Pathways in Ovine Intestinal Epithelial Cells

Escherichia coli (E. coli) F17 is a member of enterotoxigenic Escherichia coli, which can cause massive diarrhea and high mortality in newborn lambs. β-defensin is mainly produced by the epithelial tissue of the gastrointestinal tract in response to microbial infection. However, the molecular mechanism of sheep β-defensin 2 (SBD-2) against E. coli F17 remains unclear. This study aims to reveal the antibacterial ability of SBD-2 against E. coli F17 infection in sheep. Firstly, we established the culture system of ovine intestinal epithelial cells (OIECs) in vitro, treated with different concentrations of E. coli F17 for an indicated time. Secondly, we performed RNA interference and overexpression to investigate the effect of SBD-2 expression on E. coli F17 adhesion to OIECs. Finally, inhibitors of NF-κB and MAPK pathways were pre-treated to explore the possible relationship involving in E. coli F17 infection regulating SBD-2 expression. The results showed that E. coli F17 markedly (p < 0.01) upregulated the expression levels of SBD-2 mRNA and protein in a concentration- and time-dependent manner. Overexpression of SBD-2 contributed to enhancing E. coli F17 resistance in OIECs, while silencing SBD-2 dramatically improved the adhesion of E. coli F17 to OIECs (p < 0.05 or p < 0.01). Furthermore, E. coli F17 stimulated SBD-2 expression was obviously decreased by pre-treatment with NF-κB inhibitor PDTC, p38 MAPK inhibitor SB202190 and ERK1/2 MAPK inhibitor PD98095 (p < 0.05 or p < 0.01). Interestingly, adhesion of E. coli F17 to OIECs were highly enhanced by pre-treated with PDTC, SB202190 and PD98095. Our data suggested that SBD-2 could inhibit E. coli F17 infection in OIECs, possibly through NF-κB and MAPK signaling pathways. Our results provide useful theoretical basis on developing anti-infective drug and breeding for E. coli diarrhea disease-resistant sheep.

Effect of the p38 MAPK Inhibitor on the Expression of Metalloproteinases and Their Inhibitors during the Formation of Abdominal Adhesions

Background: The aim of this study was to assess the effect of blockade of the p38 mitogen-activated protein kinase (MAPK) on the expression of genes encoding metalloproteinases (MMPs) during the formation of adhesions in the abdominal cavity. Methods and Results: The experiments were carried out on male Wistar rats (n=75). The studies were carried out in two groups: Group 1 (control, n=35) – modelling the adhesive process; Group 2 (experimental, n=35) – modelling the adhesive process with intraperitoneal administration of Seroguard®—a prolonged form of the p38 MAPK inhibitor. The expression of the MMP1a, MMP2, MMP7, MMP9, and TIMP genes was assessed using real-time PCR. In the control group, overexpression of the MMP1a and MMP7 genes began from 6 hours after modeling the adhesive process, MMP9 – from Day 1, MMP2 – from Day 7 and persisted until the end of observation. With local blockade of p38 MAPK, the level of overexpression of genes encoding MMPs in the early stages was higher than in the control group (MMP1a – by Day 1; MMP7 – by 6 hours and Day 1, MMP9 – by 12 hours). From Day 3 to Day 14, the MMP1a and MMP7 expression in the experimental group was significantly lower than in the control group. Conclusion: The performed study demonstrated the involvement of different types of MMPs—collagenases (MMP1a), gelatinases (MMP2 and 9), matrilysins (MMP7)—in the rearrangement of the extracellular matrix during the process of adhesion formation in the abdominal cavity.

Biological and Cytoprotective Effect of Piper kadsura Ohwi against Hydrogen-Peroxide-Induced Oxidative Stress in Human SW1353 Cells

Oxidative stress plays a role in regulating a variety of physiological functions in living organisms and in the pathogenesis of articular cartilage diseases. Piper kadsura Ohwi is a traditional Chinese medicine that is used as a treatment for rheumatic pain, and the extracts have anti-inflammatory and antioxidant effects. However, there is still no study related to cell protection by P. kadsura. The P. kadsura extracts (PKE) were obtained by microwave-assisted extraction, liquid-liquid extraction, and column chromatography separation. The extracts could effectively scavenge free radicals in the antioxidant test, the EC50 of extracts is approximately the same as vitamin C. PKE decreased the apoptosis of SW1353 cells treated with H2O2 and could upregulate the gene expression of antioxidant enzymes (SOD-2, GPx, and CAT) and the Bcl-2/Bax ratio, as well as regulate PARP, thus conferring resistance to H2O2 attack. PKE protects cells against apoptosis caused by free radicals through the three pathways of JNK, MEK/ERK, and p38 by treatment with MAPK inhibitor. The identified components of PKE were bicyclo [2.2.1] heptan-2-ol-1,7,7-trimethyl-,(1S-endo)-, alpha-humulene, and hydroxychavicol by gas chromatography–mass spectrometry.

Repurposing melanoma chemotherapy to activate inflammasomes in treatment of BRAF/MAPK inhibitor resistant melanoma

The development of resistance to treatments of melanoma is commonly associated with upregulation of the MAPK pathway and development of an undifferentiated state. Prior studies have suggested that melanoma with these resistance characteristics may be susceptible to innate death mechanisms such as pyroptosis triggered by activation of inflammasomes. In the present studies we have taken cell lines from patients before and after development of resistance to BRAF V600 inhibitors and exposed the resistant melanoma to temozolomide (a commonly used chemotherapy) with and without chloroquine to inhibit autophagy. It was found that melanoma with an inflammatory undifferentiated state appeared susceptible to this combination when tested in vitro and in vivo against xenografts in NSG mice. Translation of the latter results into patients would promise durable responses in patients treated by the combination. The inflammasome and death mechanism involved appeared to vary between melanoma and involved either AIM2, NLRP3 or NLRC4 inflammasomes and gasdermin D or E. These preliminary studies have raised questions as to the selectivity for different inflammasomes in different melanoma and their selective targeting by chemotherapy. They also question whether the inflammatory state of melanoma may be used as biomarkers to select patients for inflammasome targeted therapy.

Overexpression of long non coding RNA OR3A4 is associated with altered p38 signalling, morphological and phenotypic changes, and reduced immunogenicity in Barretts Oesophagus

Background: Barretts Oesophagus (BO) presents a particular pathological dilemma, in that patients who have no dysplasia within their BO experience a small but significant risk of malignant progression each year. Screening programmes have attempted to reduce the mortality from BO associated oesophageal adenocarcinoma but cannot predict which BO patients will progress to invasive malignancy. We have previously identified the long non coding RNA, OR3A4, is differentially hypomethylated in progressive BO. We aimed to understand its role in BO pathogenicity Methods: The stable BO cell line CP-A, as well as the oesophageal adenocarcinoma cells line OE-33 was transfected with a lentiviral OR3A4 over-expression vector, and underwent high resolution microscopy, immunofluorescence, RT-qPCR, RNA sequencing, and targeted drug screening with the p38-MAPK inhibitor domipramod to understand the effects of OR3A4 expression on progression. We then compared progressive vs. non-progressive BO samples using quantitative multi-fluorophore (Vectra) immunohistochemistry. Results: Over-expression of OR3A4 in CP-A lines resulted in a hyperproliferative, dysplastic cellular phenotype, with strong over-expression of MAPK and anti-apoptotic pathways at the RNA and protein level, which was sensitive to the p38-MAPK inhibitor domipramod. Vectra immunohistochemistry demonstrated that progressive BO had reduced visibility associated with a reduction in CD8+ T-cells and CD68+ macrophages and reduced CD4+ T-cells in the stomal compartment. Conclusion: The overexpression of OR3A4, which we have previously shown is associated with progressive BO leads to a proliferative dysplastic cellular phenotype associated with increased, reversible MAPK signalling and loss of immune visibility.

Investigation of the Molecular Mechanisms by Which Endothelin-3 Stimulates Preadipocyte Growth

Endothelins induce many biological responses, and they are composed of three peptides: ET-1, ET-2, and ET-3. Reports have indicated that ET-1 regulates cell proliferation, adipogenesis, and other cell responses and that ET-3 stimulates the growth of gastrointestinal epithelial cells and melanocytes. However, the signalling pathways of ET3 that mediate the growth of fat cells are still unclear. Using 3T3-L1 white preadipocytes, we found that ET-3 induced increases in both cell number and BrdU incorporation. Pretreatment with an ETAR antagonist (but not an ETBR antagonist) blocked the ET-3-induced increases in both cell number and BrdU incorporation. Additionally, BQ610 suppressed the ET-3-induced increases in phosphorylation of AMPK, c-JUN, and STAT3 proteins, and pretreatment with specific inhibitors of AMPK, JNK/c-JUN, or JAK/STAT3 prevented the ET-3-induced increases in phosphorylation of AMPK, c-JUN, and STAT3, respectively. Neither p38 MAPK inhibitor nor PKC inhibitor altered the effects of ET-3 on cell growth. These data suggest that ET-3 stimulates preadipocyte growth through the ETAR, AMPK, JNK/c-JUN, and STAT3 pathways. Moreover, ET-3 did not alter HIB1B brown preadipocyte and D12 beige preadipocyte growth, suggesting a preadipocyte type-dependent effect. The results of this study may help explain how endothelin mediates fat cell activity and fat cell-associated diseases.