Serotonin regulates innate immune responses of colon epithelial cells through Nox2-derived reactive oxygen species

Regmi, Sushil Chandra; Park, Su‐Young; Ku, Sae Kwang; Kim, Jung-Ae

doi:10.1016/j.freeradbiomed.2014.02.003

Cited by 79 publications

(85 citation statements)

References 43 publications

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“…A previous study demonstrated that HT-29 cells predominantly expressed NADPH oxidase 1 [28]. To determine whether NADPH oxidase plays a crucial role in EGF-induced HO-1 expression, the NADPH oxidase inhibitor, DPI [29], was used.…”

Section: Resultsmentioning

confidence: 99%

Epidermal Growth Factor Stimulates Nuclear Factor-κB Activation and Heme Oxygenase-1 Expression via c-Src, NADPH Oxidase, PI3K, and Akt in Human Colon Cancer Cells

Lien

Bien

et al. 2014

PLoS ONE

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Previous report showed that epidermal growth factor (EGF) promotes tumor progression. Several studies demonstrated that growth factors can induce heme oxygenase (HO)-1 expression, protect against cellular injury and cancer cell proliferation. In this study, we investigated the involvement of the c-Src, NADPH oxidase, reactive oxygen species (ROS), PI3K/Akt, and NF-κB signaling pathways in EGF-induced HO-1 expression in human HT-29 colon cancer cells. Treatment of HT-29 cells with EGF caused HO-1 to be expressed in concentration- and time-dependent manners. Treatment of HT-29 cells with AG1478 (an EGF receptor (EGFR) inhibitor), small interfering RNA of EGFR (EGFR siRNA), a dominant negative mutant of c-Src (c-Src DN), DPI (an NADPH oxidase inhibitor), glutathione (an ROS inhibitor), LY294002 (a PI3K inhibitor), and an Akt DN inhibited EGF-induced HO-1 expression. Stimulation of cells with EGF caused an increase in c-Src phosphorylation at Tyr406 in a time-dependent manner. Treatment of HT-29 cells with EGF induced an increase in p47phox translocation from the cytosol to membranes. The EGF-induced ROS production was inhibited by DPI. Stimulation of cells with EGF resulted in an increase in Akt phosphorylation at Ser473, which was inhibited by c-Src DN, DPI, and LY 294002. Moreover, treatment of HT-29 cells with a dominant negative mutant of IκB (IκBαM) inhibited EGF-induced HO-1 expression. Stimulation of cells with EGF induced p65 translocation from the cytosol to nuclei. Treatment of HT-29 cells with EGF induced an increase in κB-luciferase activity, which was inhibited by a c-Src DN, LY 294002, and an Akt DN. Furthermore, EGF-induced colon cancer cell proliferation was inhibited by Sn(IV)protoporphyrin-IX (snPP, an HO-1 inhibitor). Taken together, these results suggest that the c-Src, NADPH oxidase, PI3K, and Akt signaling pathways play important roles in EGF-induced NF-κB activation and HO-1 expression in HT-29 cells. Moreover, overexpression of HO-1 mediates EGF-induced colon cancer cell proliferation.

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Section: Resultsmentioning

confidence: 99%

Epidermal Growth Factor Stimulates Nuclear Factor-κB Activation and Heme Oxygenase-1 Expression via c-Src, NADPH Oxidase, PI3K, and Akt in Human Colon Cancer Cells

Lien

Bien

et al. 2014

PLoS ONE

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“…Because we found that Nox1-KO mice have a significant increase of goblet cells in the cecum and colon and because goblet cells secrete mucus to form a barrier to fend off bacterial infection[14,16], the protective effect of Nox1-deficiency is likely due to the increase in goblet cells rather than a direct effect of ROS production. The strong protective effect of Cyba deficiency against C. rodentium and L. monocytogenes may have contributions from multiple Nox deficiencies, because Nox2 is induced in the intestinal epithelium by serotonin, a neuroendocrine secreted by enterochromaffin cells[21]. …”

Section: Discussionmentioning

confidence: 99%

NADPH oxidase-1 deficiency offers little protection in Salmonella typhimurium-induced typhlitis in mice

Chu¹,

Esworthy²,

Doroshow³

et al. 2016

WJG

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AIMTo test whether Nox1 plays a role in typhlitis induced by Salmonella enterica serovar Typhimurium (S. Tm) in a mouse model.METHODSEight-week-old male wild-type (WT) and Nox1 knockout (KO) C57BL6/J (B6) mice were administered metronidazole water for 4 d to make them susceptible to S. Tm infection by the oral route. The mice were given plain water and administered with 4 different doses of S. Tm by oral gavage. The mice were followed for another 4 d. From the time of the metronidazole application, the mice were observed twice daily and weighed daily. The ileum, cecum and colon were removed for sampling at the fourth day post-inoculation. Portions of all three tissues were fixed for histology and placed in RNAlater for mRNA/cDNA preparation and quantitative real-time PCR. The contents of the cecum were recovered for estimation of S. Tm CFU.RESULTSWe found Nox1-knockout (Nox1-KO) mice were not more sensitive to S. Tm colonization and infection than WT B6 mice. This conclusion is based on the following observations: (1) S. Tm-infection induced similar weight loss in Nox1-KO mice compared to WT mice; (2) the same S. Tm CFU was recovered from the cecal content of Nox1-KO and WT mice regardless of the inoculation dose, except the lowest inoculation dose (2 × 106 CFU) for which the Nox1-KO had one-log lower CFU than WT mice; (3) there is no difference in cecal pathology between WT and Nox1-KO groups; and (4) there are no S. Tm infection-induced changes in gene expression levels (IL-1b, TNF-α, and Duox2) between WT and Nox1-KO groups. The Alpi gene expression was more suppressed by S. Tm treatment in WT than the Nox1-KO cecum.CONCLUSIONNox1 does not protect mice from S. Tm colonization. Nox1-KO provides a very minor protective effect against S. Tm infection. Using NOX1-specific inhibitors for colitis therapy should not increase risks in bacterial infection.

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“…To complete the formation of an active NOX2 complex, GTP-bound Rac1 is recruited to the membrane bound to p67phox, a required step for a functional NOX2 complex (Figure 1; Gorzalczany et al, 2000; Miyano et al, 2006; Panday et al, 2015). There is increasing evidence showing NOX2 can be expressed in other cell types other than professional phagocytes such as endothelial cells and colon epithelial cells (Kolářová et al, 2010; Regmi et al, 2014). Despite this, NOX2-ROS has not been studied in these cell types for anti-microbial functions but rather as secondary or regulatory signals (Kolářová et al, 2010; Dikalov, 2011; Fang, 2011; Paiva and Bozza, 2014; Regmi et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…There is increasing evidence showing NOX2 can be expressed in other cell types other than professional phagocytes such as endothelial cells and colon epithelial cells (Kolářová et al, 2010; Regmi et al, 2014). Despite this, NOX2-ROS has not been studied in these cell types for anti-microbial functions but rather as secondary or regulatory signals (Kolářová et al, 2010; Dikalov, 2011; Fang, 2011; Paiva and Bozza, 2014; Regmi et al, 2014). However, the increasing knowledge of the role of epithelium in innate immunity against invading bacteria generates the need for characterization of potential antibacterial pathways such as NOX2 in the epithelial cells.…”

Section: Introductionmentioning

confidence: 99%

Opportunistic Pathogen Porphyromonas gingivalis Modulates Danger Signal ATP-Mediated Antibacterial NOX2 Pathways in Primary Epithelial Cells

Roberts

Atanasova

Lee

et al. 2017

Front. Cell. Infect. Microbiol.

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Porphyromonas gingivalis, a major opportunistic pathogen in the etiology of chronic periodontitis, successfully survives in human gingival epithelial cells (GECs). P. gingivalis abrogates the effects of a host danger molecule, extracellular ATP (eATP)/P2X7 signaling, such as the generation of reactive oxygen species (ROS) via the mitochondria and NADPH oxidases (NOX) from primary GECs. However, antimicrobial functions of ROS production are thoroughly investigated in myeloid-lineage immune cells and have not been well-understood in epithelial cells. Therefore, this study characterizes antibacterial NOX2 generated ROS and host downstream effects in P. gingivalis infected human primary GECs. We examined the expression of NOX isoforms in the GECs and demonstrate eATP stimulation increased the mRNA expression of NOX2 (p < 0.05). Specific peptide inhibition of NOX2 significantly reduced eATP-mediated ROS as detected by DCFDA probe. The results also showed P. gingivalis infection can temporally modulate NOX2 pathway by reorganizing the localization and activation of cytosolic molecules (p47phox, p67phox, and Rac1) during 24 h of infection. Investigation into downstream biocidal factors of NOX2 revealed an eATP-induced increase in hypochlorous acid (HOCl) in GECs detected by R19-S fluorescent probe, which is significantly reduced by a myeloperoxidase (MPO) inhibitor. MPO activity of the host cells was assayed and found to be positively affected by eATP treatment and/or infection. However, P. gingivalis significantly reduced the MPO product, bactericidal HOCl, in early times of infection upon eATP stimulation. Analysis of the intracellular levels of a major host-antioxidant, glutathione during early infection revealed a substantial decrease (p < 0.05) in reduced glutathione indicative of scavenging of HOCl by P. gingivalis infection and eATP treatment. Examination of the mRNA expression of key enzymes in the glutathione synthesis pathway displayed a marked increase (p < 0.05) in glutamate cysteine ligase (GCL) subunits GCLc and GCLm, glutathione synthetase, and glutathione reductase during the infection. These suggest P. gingivalis modulates the danger signal eATP-induced NOX2 signaling and also induces host glutathione synthesis to likely avoid HOCl mediated clearance. Thus, we characterize for the first time in epithelial cells, an eATP/NOX2-ROS-antibacterial pathway and demonstrate P. gingivalis can circumvent this important antimicrobial defense system potentially for successful persistence in human epithelial tissues.

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Serotonin regulates innate immune responses of colon epithelial cells through Nox2-derived reactive oxygen species

Cited by 79 publications

References 43 publications

Epidermal Growth Factor Stimulates Nuclear Factor-κB Activation and Heme Oxygenase-1 Expression via c-Src, NADPH Oxidase, PI3K, and Akt in Human Colon Cancer Cells

Epidermal Growth Factor Stimulates Nuclear Factor-κB Activation and Heme Oxygenase-1 Expression via c-Src, NADPH Oxidase, PI3K, and Akt in Human Colon Cancer Cells

NADPH oxidase-1 deficiency offers little protection in Salmonella typhimurium-induced typhlitis in mice

Opportunistic Pathogen Porphyromonas gingivalis Modulates Danger Signal ATP-Mediated Antibacterial NOX2 Pathways in Primary Epithelial Cells

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