scholarly journals Microbial signals and lymphotoxin drive TNF-independent death of A20 and ABIN-1 deficient epithelium

2021 ◽  
Author(s):  
Iulia Rusu ◽  
Elvira Mennillo ◽  
Jared L Bain ◽  
Zhongmei Li ◽  
Xiaofei Sun ◽  
...  

Anti-TNF antibodies are effective for treating patients with inflammatory bowel disease (IBD), but many patients fail to respond to anti-TNF therapy, highlighting the importance of TNF-independent disease. We previously demonstrated that acute deletion of two IBD susceptibility genes, A20 (Tnfaip3) and Abin-1 (Tnip1), in intestinal epithelial cells (IECs) sensitizes mice to both TNF-dependent and TNF-independent death. Here we show that TNF-independent IEC death after A20 and Abin-1 deletion is rescued by germ-free derivation or deletion of MyD88, while deletion of Trif provides only partial protection. Combined deletion of Ripk3 and Casp8, which inhibits both apoptotic and necroptotic death, completely protects against death after acute deletion of A20 and Abin-1 in IECs. A20 and Abin-1-deficient IECs are sensitized to TNF-independent, TNFR-1-mediated death in response to lymphotoxin alpha (LTα) homotrimers. Blockade of LTα in vivo reduces weight loss and improves survival when combined with partial deletion of MyD88. These data show that microbial signals, MyD88, and LTα all contribute to TNF-independent intestinal injury.

2021 ◽  
Author(s):  
Jagadish Koya ◽  
Tong Shen ◽  
Geming Lu ◽  
Alex Gauthier ◽  
Lin Mantell ◽  
...  

Abstract Background: Inflammatory bowel disease (IBD) affects almost 7 million people worldwide and is increasing in incidence. While the precise pathogenesis of IBD remains unknown, the production of inflammatory cytokines and chemokines play a central role. We have previously found that N,N-dimethylacetamide (DMA), a widely used non-toxic drug excipient, suppresses cytokine and chemokine secretion in vitro and prevents inflammation-induced preterm birth in vivo. Methods: Using sandwich enzyme-linked immunosorbent assays (ELISAs), we tested whether DMA attenuates cytokine and chemokine secretion from LPS- or TNFa-stimulated human intestinal epithelial cells and human monocytes and HMGB1 release from RAW 264.7 cells. To test our hypothesis that the mechanism of DMA’s effects in in-vitro and in-vivo models of IBD is inhibition of the NF-kB pathway, we used western blotting to track levels of the nuclear factor kappa B (NF-kB) inhibitory molecule I kappa B alpha (IkBa) in THP-1 human monocytes in the absence or presence of DMA. Finally, we induced colitis in C57Bl/6 mice with dextran sodium sulfate (DSS) and then tested whether daily i.p injections of DMA at 2.1 g/kg/day attenuates clinical and histopathologic signs of colitis.Results: DMA attenuated cytokine and chemokine release from human intestinal epithelial cells and human monocytes and HMGB1 release from RAW 264.7 cells. Importantly, DMA prevented degradation of IkBa in THP-1 cells, thereby suggesting one mechanism for DMA’s effects. Finally, we show here, for the first time, that DMA attenuates clinical and histologic features of DSS-induced colitis. Conclusion: DMA should be further explored in preclinical and clinical trials for its potential as novel drug therapy for IBD.


2021 ◽  
Author(s):  
Jagadish Koya ◽  
Tong Shen ◽  
Geming Lu ◽  
Alex Gauthier ◽  
Lin Mantell ◽  
...  

Abstract Inflammatory bowel disease (IBD) affects almost 7 million people worldwide and is increasing in incidence. While the precise pathogenesis of IBD remains unknown, the production of inflammatory cytokines and chemokines play a central role. We have previously found that N,N-dimethylacetamide (DMA), a widely used non-toxic drug excipient, suppresses cytokine and chemokine secretion in vitro and prevents inflammation-induced preterm birth in vivo. Using sandwich enzyme-linked immunosorbent assays (ELISAs), we tested whether DMA attenuates cytokine and chemokine secretion from LPS- or TNFa-stimulated human intestinal epithelial cells and human monocytes and HMGB1 release from RAW 264.7 cells. To test our hypothesis that the mechanism of DMA’s effects in in-vitro and in-vivo models of IBD is inhibition of the NF-kB pathway, we used western blotting to track levels of the nuclear factor kappa B (NF-kB) inhibitory molecule I kappa B alpha (IkBa) in THP-1 human monocytes in the absence or presence of DMA. Finally, we induced colitis in C57Bl/6 mice with dextran sodium sulfate (DSS) and then tested whether daily i.p injections of DMA at 2.1 g/kg/day attenuates clinical and histopathologic signs of colitis. DMA attenuated cytokine and chemokine release from human intestinal epithelial cells and human monocytes and HMGB1 release from RAW 264.7 cells. Importantly, DMA prevented degradation of IkBa in THP-1 cells, thereby suggesting one mechanism for DMA’s effects. Finally, we show here, for the first time, that DMA attenuates clinical and histologic features of DSS-induced colitis. Based on these data, DMA should be further explored in preclinical and clinical trials for its potential as novel drug therapy for IBD.


2020 ◽  
Vol 295 (13) ◽  
pp. 4237-4251 ◽  
Author(s):  
Jie Zhang ◽  
Min Xu ◽  
Weihua Zhou ◽  
Dejian Li ◽  
Hong Zhang ◽  
...  

Parkinson disease autosomal recessive, early onset 7 (PARK7 or DJ-1) is involved in multiple physiological processes and exerts anti-apoptotic effects on multiple cell types. Increased intestinal epithelial cell (IEC) apoptosis and excessive activation of the p53 signaling pathway is a hallmark of inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD). However, whether DJ-1 plays a role in colitis is unclear. To determine whether DJ-1 deficiency is involved in the p53 activation that results in IEC apoptosis in colitis, here we performed immunostaining, real-time PCR, and immunoblotting analyses to assess DJ-1 expression in human UC and CD samples. In the inflamed intestines of individuals with IBD, DJ-1 expression was decreased and negatively correlated with p53 expression. DJ-1 deficiency significantly aggravated colitis, evidenced by increased intestinal inflammation and exacerbated IEC apoptosis. Moreover, DJ-1 directly interacted with p53, and reduced DJ-1 levels increased p53 levels both in vivo and in vitro and were associated with decreased p53 degradation via the lysosomal pathway. We also induced experimental colitis with dextran sulfate sodium in mice and found that compared with DJ-1−/− mice, DJ-1−/−p53−/− mice have reduced apoptosis and inflammation and increased epithelial barrier integrity. Furthermore, pharmacological inhibition of p53 relieved inflammation in the DJ-1−/− mice. In conclusion, reduced DJ-1 expression promotes inflammation and IEC apoptosis via p53 in colitis, suggesting that the modulation of DJ-1 expression may be a potential therapeutic strategy for managing colitis.


2000 ◽  
Vol 68 (12) ◽  
pp. 7010-7017 ◽  
Author(s):  
Elke Cario ◽  
Daniel K. Podolsky

ABSTRACT Initiation and perpetuation of the inflammatory intestinal responses in inflammatory bowel disease (IBD) may result from an exaggerated host defense reaction of the intestinal epithelium to endogenous lumenal bacterial flora. Intestinal epithelial cell lines constitutively express several functional Toll-like receptors (TLRs) which appear to be key regulators of the innate response system. The aim of this study was to characterize the expression pattern of TLR2, TLR3, TLR4, and TLR5 in primary intestinal epithelial cells from patients with IBD. Small intestinal and colonic biopsy specimens were collected from patients with IBD (Crohn's disease [CD], ulcerative colitis [UC]) and controls. Non-IBD specimens were assessed by immunofluorescence histochemistry using polyclonal antibodies specific for TLR2, TLR3, TLR4, and TLR5. Primary intestinal epithelial cells (IEC) of normal mucosa constitutively expressed TLR3 and TLR5, while TLR2 and TLR4 were only barely detectable. In active IBD, the expression of TLR3 and TLR4 was differentially modulated in the intestinal epithelium. TLR3 was significantly downregulated in IEC in active CD but not in UC. In contrast, TLR4 was strongly upregulated in both UC and CD. TLR2 and TLR5 expression remained unchanged in IBD. These data suggest that IBD may be associated with distinctive changes in selective TLR expression in the intestinal epithelium, implying that alterations in the innate response system may contribute to the pathogenesis of these disorders.


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