Disrupted Barrier Function through Epithelial Cell Apoptosis

Schulzke, Joerg-Dieter; Bojarski, Christian; Zeißig, Sebastian; Heller, Frank; Gitter, A. H.; Fromm, Michael

doi:10.1196/annals.1326.027

Cited by 164 publications

(113 citation statements)

References 15 publications

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“…Increased rates of organ-specific cell death are considered to be involved in the pathophysiology of MODS in a variety of systemic disorders, including heatstroke (35,52), contributing to the breakdown of intestinal barrier function observed during endotoxemia (13,15,39,66,80,85). Increased physiological levels of inflammatory stimuli can promote an increase in cellular apoptosis (52,63), which is supported by the finding that TNF receptor shares intracellular signaling domains with FAS/CD95, a crucial receptor involved with apoptotic signaling (48).…”

Section: Discussionsupporting

confidence: 49%

Expression of intracellular cytokines, HSP72, and apoptosis in monocyte subsets during exertional heat stress in trained and untrained individuals

Selkirk¹,

McLellan²,

Wright³

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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Selkirk GA, McLellan TM, Wright HE, Rhind SG. Expression of intracellular cytokines, HSP72, and apoptosis in monocyte subsets during exertional heat stress in trained and untrained individuals. Am J Physiol Regul Integr Comp Physiol 296: R575-R586, 2009. First published January 21, 2009 doi:10.1152/ajpregu.90683.2008.-This study examined intracellular cytokine, heat shock protein (HSP) 72, and cellular apoptosis in classic and inflammatory CD14 ϩ monocyte subsets during exertional heat stress (EHS). Subjects were divided into endurance-trained [TR; n ϭ 12, peak aerobic power (V O2peak) ϭ 70 Ϯ 2 ml⅐ kg lean body mass (LBM) Ϫ1 ⅐ min Ϫ1 ] and sedentary-untrained (UT; n ϭ 11, V O2peak ϭ 50 Ϯ 1 ml⅐ kg LBM Ϫ1 ⅐ min Ϫ1 ) groups before walking at 4.5 km/h with 2% elevation in a climatic chamber (40°C, 30% relative humidity) wearing protective clothing until exhaustion (Exh). Venous blood samples at baseline and 0.5°C rectal temperature increments (38.0, 38.5, 39.0, 39.5, and 40.0°C/Exh) were analyzed for cytokines (TNF-␣, IL-1␤, IL-6, IL-1ra, and IL-10) in CD14 ϩϩ CD16 Ϫ /CD14 ϩ CD16 ϩ and HSP72/apoptosis in CD14 Bri / CD14 Dim subsets. In addition, serum levels of extracellular (e)HSP72 were also examined. Baseline and Exh samples were separately stimulated with LPS (1 g/ml) or heat shocked (42°C) and cultured in vitro for 2 h. A greater temperature-dependent increase in CD14 ϩ CD16 ϩ cells was observed in TR compared with UT subjects as well as a greater LPS tolerance following in vitro LPS stimulation. TNF-␣ and IL-1␤ cytokine expression was elevated in CD14 ϩ CD16 ϩ but not in CD14 ϩϩ CD16 Ϫ cells. A greater induction of intracellular HSP72 and eHSP72 was observed in TR compared with UT subjects, which coincided with reduced apoptosis at Exh and following in vitro heat shock. Induced HSP in vitro was not uniform across CD14 ϩ subsets. Findings suggest that circulating CD14 ϩ CD16 ϩ , but not CD14 ϩϩ CD16 Ϫ monocytes, contribute to the proinflammatory cytokine profiles observed during EHS. In addition, the enhanced HSP72 response in endurance-trained individuals may confer improved heat tolerance through both anti-inflammatory and anti-apoptotic mechanisms. immune function; cardiovascular/thermoregulatory strain; flow cytometry; heat shock protein PERIPHERAL BLOOD MONOCYTES play an important role in protection against invading pathogens and activation of innate immunity (46). Based on differential expression of antigenic markers CD14 [part of the LPS receptor, CD14/Toll-like receptor (TLR-4)/MD-2] and CD16 (Fc␥RIII), monocytes can be divided into two phenotypically and functionally distinct subsets (82, 90). The bulk of monocytes are defined as classic monocytes and are strongly positive for surface receptor CD14 (CD14 ϩϩ CD16 Ϫ ), whereas the minor subset are referred to as inflammatory monocytes (CD14 ϩ CD16 ϩ ) because of their high capacity to express proinflammatory cytokines such as TNF-␣ (6, 62, 64, 90). Inflammatory monocytes have the ability to respond directly with antimicrobial activity, whereas the clas...

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Section: Discussionsupporting

confidence: 49%

Expression of intracellular cytokines, HSP72, and apoptosis in monocyte subsets during exertional heat stress in trained and untrained individuals

Selkirk¹,

McLellan²,

Wright³

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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“…9,12,13,[32][33][34] Cell death by apoptosis is a major contributor of organ dysfunction in these diseases. Currently, there are no effective treatments available to treat ischemia reperfusion injury or chemical-induced organ injury.…”

Section: Discussionmentioning

confidence: 99%

UNC5B Receptor Deletion Exacerbates Tissue Injury in Response to AKI

Ranganathan

Jayakumar

Navankasattusas

et al. 2014

Journal of the American Society of Nephrology

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Netrin-1 regulates cell survival and apoptosis by activation of its receptors, including UNC5B. However, the in vivo role of UNC5B in cell survival during cellular stress and tissue injury is unknown. We investigated the role of UNC5B in cell survival in response to stress using mice heterozygously expressing the UNC5B gene (UNC5B 2/flox ) and mice with targeted homozygous deletion of UNC5B in kidney epithelial cells (UNC5B 2/flox/GGT-cre ). Mice were subjected to two different models of organ injury: ischemia reperfusion injury of the kidney and cisplatin-induced nephrotoxicity. Both mouse models of UNC5B depletion had normal organ function and histology under basal conditions. After AKI, however, UNC5B 2/flox/GGT-cre mice exhibited significantly worse renal function and damage, increased tubular apoptosis, enhanced p53 activation, and exacerbated inflammation compared with UNC5B 2/flox and wild-type mice. shRNA-mediated suppression of UNC5B expression in cultured tubular epithelial cells exacerbated cisplatin-induced cell death in a p53-dependent manner and blunted Akt phosphorylation. Inhibition of PI3 kinase similarly exacerbated cisplatin-induced apoptosis; in contrast, overexpression of UNC5B reduced cisplatin-induced apoptosis in these cells. Taken together, these results show that the netrin-1 receptor UNC5B plays a critical role in cell survival and kidney injury through Akt-mediated inactivation of p53 in response to stress.

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“…epithelial apoptosis (1)(2)(3)(4). By exposure of the inflammatory cells within the lamina propria (LP) to intraluminal Ags in a nonselective way, an unspecific inflammatory response is elicited, which in turn could promote additional tissue damage or even evolve into sustained inflammatory activity.…”

mentioning

confidence: 99%

Hydroxylase Inhibition Abrogates TNF-α–Induced Intestinal Epithelial Damage by Hypoxia-Inducible Factor-1–Dependent Repression of FADD

Hindryckx

Vos

Jacques

et al. 2010

The Journal of Immunology

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Hydroxylase inhibitors stabilize hypoxia-inducible factor-1 (HIF-1), which has barrier-protective activity in the gut. Because the inflammatory cytokine TNF-α contributes to inflammatory bowel disease in part by compromising intestinal epithelial barrier integrity, hydroxylase inhibition may have beneficial effects in TNF-α–induced intestinal epithelial damage. The hydroxylase inhibitor dimethyloxalylglycin (DMOG) was tested in a murine model of TNF-α–driven chronic terminal ileitis. DMOG-treated mice experienced clinical benefit and showed clear attenuation of chronic intestinal inflammation compared with that of vehicle-treated littermates. Additional in vivo and in vitro experiments revealed that DMOG rapidly restored terminal ileal barrier function, at least in part through prevention of TNF-α–induced intestinal epithelial cell apoptosis. Subsequent transcriptional studies indicated that DMOG repressed Fas-associated death domain protein (FADD), a critical adaptor molecule in TNFR-1-mediated apoptosis, in an HIF-1α–dependent manner. Loss of this FADD repression by HIF-1α-targeting small interfering RNA significantly diminished the antiapoptotic action of DMOG. Additional molecular studies led to the discovery of a previously unappreciated HIF-1 binding site in the FADD promoter, which controls repression of FADD during hypoxia. As such, the results reported in this study allowed the identification of an innate mechanism that protects intestinal epithelial cells during (inflammatory) hypoxia, by direct modulation of death receptor signaling. Hydroxylase inhibition could represent a promising alternative treatment strategy for hypoxic inflammatory diseases, including inflammatory bowel disease.

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Disrupted Barrier Function through Epithelial Cell Apoptosis

Cited by 164 publications

References 15 publications

Expression of intracellular cytokines, HSP72, and apoptosis in monocyte subsets during exertional heat stress in trained and untrained individuals

Expression of intracellular cytokines, HSP72, and apoptosis in monocyte subsets during exertional heat stress in trained and untrained individuals

UNC5B Receptor Deletion Exacerbates Tissue Injury in Response to AKI

Hydroxylase Inhibition Abrogates TNF-α–Induced Intestinal Epithelial Damage by Hypoxia-Inducible Factor-1–Dependent Repression of FADD

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