Trichinella spiralis excretory/secretory proteins mediated larval invasion via inducing gut epithelial apoptosis and barrier disruption.
<h4>Background</h4>Intestinal larva invasion is a crucial step of Trichinella spiralis infection. Intestinal infective larvae (IIL) and their excretory/secretory proteins (ESP) interact with gut epithelium, which often results in gut epithelium barrier injuries. Previous studies showed w...
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Public Library of Science (PLoS)
2025-01-01
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| Series: | PLoS Neglected Tropical Diseases |
| Online Access: | https://doi.org/10.1371/journal.pntd.0012842 |
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| author | Qi Qi Lu Wen Wen Zheng Zhao Yu Zhang Pei Kun Cong Xin Guo Yao Zhang Xin Zhuo Zhang Shao Rong Long Ruo Dan Liu Zhong Quan Wang Jing Cui |
| author_facet | Qi Qi Lu Wen Wen Zheng Zhao Yu Zhang Pei Kun Cong Xin Guo Yao Zhang Xin Zhuo Zhang Shao Rong Long Ruo Dan Liu Zhong Quan Wang Jing Cui |
| author_sort | Qi Qi Lu |
| collection | DOAJ |
| description | <h4>Background</h4>Intestinal larva invasion is a crucial step of Trichinella spiralis infection. Intestinal infective larvae (IIL) and their excretory/secretory proteins (ESP) interact with gut epithelium, which often results in gut epithelium barrier injuries. Previous studies showed when T. spiralis invaded intestinal epithelium cells, the IIL ESP disrupted the tight junctions (TJs) of Caco-2 monolayer, but the mechanism is not clear. The IIL ESP might cause gut epithelial apoptosis, weaken the gut barrier and aid the larval invasion. The aim of this study was to investigate whether T. spiralis IIL ESP participate in enterocyte apoptosis and disrupt gut epithelial barrier to promote the larval invasion.<h4>Methodology/principal findings</h4>Cell viability was assessed by CCK-8 assay and the results showed that 200 μg/ml of IIL ESP incubated with Caco-2 cells for 18 h inhibited the Caco-2 cell viability. The results of trans-epithelial electrical resistance (TEER) and FITC-dextran showed that IIL ESP decreased the TEER, increased FITC-dextran flux in Caco-2 monolayer. qPCR, Western blot and immunofluorescence test (IFT) showed that IIL ESP decreased the mRNA and protein expression of TJs (ZO-1, E-cad, Occludin and Claudin-1). The IIL ESP-induced Caco-2 cell apoptosis was observed by DAPI, Hoechst 33358, TUNEL and Annexin V/PI staining. Besides, flow cytometry revealed an increasing apoptosis rate in Caco-2 cells after the IIL ESP treatment. qPCR and Western blot analysis indicated that IIL ESP activated caspases (Caspase 3, Caspase 9 and Caspase 8), up-regulated the pro-apoptotic factors (Bax and Cytochrome c) and down-regulated the anti-apoptosis molecule Bcl-2. Interestingly, pretreatment of Caco-2 cells with apoptosis inhibitor Z-VAD-FMK abrogated and recovered the barrier function of Caco-2 monolayer destroyed by IIL ESP. Furthermore, the Z-VAD-FMK pretreatment also impeded the in vitro larva invasion of Caco-2 monolayer.<h4>Conclusions</h4>T. spiralis IIL ESP induced gut epithelial apoptosis, reduced the TJs expression, damaged gut epithelial integrity and barrier function, and promoted larval invasion. These findings provided a basis of further understanding the interaction mechanism between T. spiralis and host gut epithelium, and they were valuable to the development new prevention and therapeutic strategy of early T. spiralis infection. |
| format | Article |
| id | doaj-art-c8e88639b500439584aa45b3db2e6d53 |
| institution | Kabale University |
| issn | 1935-2727 1935-2735 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Public Library of Science (PLoS) |
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| spelling | doaj-art-c8e88639b500439584aa45b3db2e6d532025-02-09T05:30:51ZengPublic Library of Science (PLoS)PLoS Neglected Tropical Diseases1935-27271935-27352025-01-01191e001284210.1371/journal.pntd.0012842Trichinella spiralis excretory/secretory proteins mediated larval invasion via inducing gut epithelial apoptosis and barrier disruption.Qi Qi LuWen Wen ZhengZhao Yu ZhangPei Kun CongXin GuoYao ZhangXin Zhuo ZhangShao Rong LongRuo Dan LiuZhong Quan WangJing Cui<h4>Background</h4>Intestinal larva invasion is a crucial step of Trichinella spiralis infection. Intestinal infective larvae (IIL) and their excretory/secretory proteins (ESP) interact with gut epithelium, which often results in gut epithelium barrier injuries. Previous studies showed when T. spiralis invaded intestinal epithelium cells, the IIL ESP disrupted the tight junctions (TJs) of Caco-2 monolayer, but the mechanism is not clear. The IIL ESP might cause gut epithelial apoptosis, weaken the gut barrier and aid the larval invasion. The aim of this study was to investigate whether T. spiralis IIL ESP participate in enterocyte apoptosis and disrupt gut epithelial barrier to promote the larval invasion.<h4>Methodology/principal findings</h4>Cell viability was assessed by CCK-8 assay and the results showed that 200 μg/ml of IIL ESP incubated with Caco-2 cells for 18 h inhibited the Caco-2 cell viability. The results of trans-epithelial electrical resistance (TEER) and FITC-dextran showed that IIL ESP decreased the TEER, increased FITC-dextran flux in Caco-2 monolayer. qPCR, Western blot and immunofluorescence test (IFT) showed that IIL ESP decreased the mRNA and protein expression of TJs (ZO-1, E-cad, Occludin and Claudin-1). The IIL ESP-induced Caco-2 cell apoptosis was observed by DAPI, Hoechst 33358, TUNEL and Annexin V/PI staining. Besides, flow cytometry revealed an increasing apoptosis rate in Caco-2 cells after the IIL ESP treatment. qPCR and Western blot analysis indicated that IIL ESP activated caspases (Caspase 3, Caspase 9 and Caspase 8), up-regulated the pro-apoptotic factors (Bax and Cytochrome c) and down-regulated the anti-apoptosis molecule Bcl-2. Interestingly, pretreatment of Caco-2 cells with apoptosis inhibitor Z-VAD-FMK abrogated and recovered the barrier function of Caco-2 monolayer destroyed by IIL ESP. Furthermore, the Z-VAD-FMK pretreatment also impeded the in vitro larva invasion of Caco-2 monolayer.<h4>Conclusions</h4>T. spiralis IIL ESP induced gut epithelial apoptosis, reduced the TJs expression, damaged gut epithelial integrity and barrier function, and promoted larval invasion. These findings provided a basis of further understanding the interaction mechanism between T. spiralis and host gut epithelium, and they were valuable to the development new prevention and therapeutic strategy of early T. spiralis infection.https://doi.org/10.1371/journal.pntd.0012842 |
| spellingShingle | Qi Qi Lu Wen Wen Zheng Zhao Yu Zhang Pei Kun Cong Xin Guo Yao Zhang Xin Zhuo Zhang Shao Rong Long Ruo Dan Liu Zhong Quan Wang Jing Cui Trichinella spiralis excretory/secretory proteins mediated larval invasion via inducing gut epithelial apoptosis and barrier disruption. PLoS Neglected Tropical Diseases |
| title | Trichinella spiralis excretory/secretory proteins mediated larval invasion via inducing gut epithelial apoptosis and barrier disruption. |
| title_full | Trichinella spiralis excretory/secretory proteins mediated larval invasion via inducing gut epithelial apoptosis and barrier disruption. |
| title_fullStr | Trichinella spiralis excretory/secretory proteins mediated larval invasion via inducing gut epithelial apoptosis and barrier disruption. |
| title_full_unstemmed | Trichinella spiralis excretory/secretory proteins mediated larval invasion via inducing gut epithelial apoptosis and barrier disruption. |
| title_short | Trichinella spiralis excretory/secretory proteins mediated larval invasion via inducing gut epithelial apoptosis and barrier disruption. |
| title_sort | trichinella spiralis excretory secretory proteins mediated larval invasion via inducing gut epithelial apoptosis and barrier disruption |
| url | https://doi.org/10.1371/journal.pntd.0012842 |
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