Su1309 – Impact of Gut Surgical Manipulation on Enteric Glia, Ca2+ Waves, ADP Signaling, Neural-Glial Communication, ET-1 Siganling and Molecular Signaling in a Mouse Model of Postoperative Ileus

Abstract Background Chinese medicine decoction Da-Cheng-Qi-Tang (DCQT) is effective for treating gastrointestinal (GI) disorders, including postoperative ileus (POI); however, the mechanism by which DCQT improves intestinal motility of POI remains unknown. Purpose The aim of this study is to explore the therapeutic effect and mechanism of the decoction with the traditional formula DCQT (T-DCQT) and a modified DCQT (M-DCQT) in an experimental POI mouse model. Methods Mice were divided into 5 experimental groups with 16 mice per group as follows: (1) control group; (2) sham group; (3) POI group; (4) T-DCQT group and (5) M-DCQT group. Each group was subdivided into 2 groups in which the therapeutic effect was examined at 24h and 48h after operation. POI was induced by classic intestinal manipulation operation and the gastrointestinal(GI) motility was measured with a charcoal marking mixture gavage. The intestinal tissues were collected for evaluation of the histopathological alteration, and analysis of the expression of inflammatory signal pathways, as NF-κB, p38 MAPK, and TLR4 by qPCR, immunohistochemical staining and western-blotting, respectively. Plasma inflammatory cytokines were determined using a high-throughput liquid chip. All analyses were performed with samples collected 24 and/or 48h after operation. Results GI transit was significantly reduced in mice with POI and this dysfunction was alleviated after administration of either T-DCQT or M-DCQT enema. When compared to controls, the pathological changes in the ileum mucosal of POI mice were significantly improved, and the increased expression of NF-κB, p38 MAPK, and TLR4 in the intestinal tissues were reversed, following T- DCQT or M-DCQT treatment. Plasma inflammatory cytokines, such as IL-1α, IL-6, MCP-1, MIP-1β and IL-17 levels were significantly highly expressed in POI group, and most of them, as IL-1α, IL-6, MIP-1β and IL-17 were significantly reduced after T-DCQT or M-DCQT treatment. Conclusion The current study indicated that administration of T-DCQT or M-DCOT could ameliorate the POI-associated inflammatory response and improve GI motility, by controlling inflammatory cytokines release and modulating the expression of some inflammatory signal pathways in the POI mouse model.

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Inhibition of SETMAR–H3K36me2–NHEJ repair axis in residual disease cells prevents glioblastoma recurrence

Neuro-Oncology ◽

10.1093/neuonc/noaa128 ◽

2020 ◽

Vol 22 (12) ◽

pp. 1785-1796

Author(s):

Ekjot Kaur ◽

Jyothi Nair ◽

Atanu Ghorai ◽

Saket V Mishra ◽

Anagha Achareker ◽

...

Keyword(s):

Mouse Model ◽

Residual Disease ◽

Fusion Gene ◽

Molecular Signaling ◽

End Joining ◽

Orthotopic Mouse Model ◽

Nhej Pathway ◽

Nhej Repair

Abstract Background Residual disease of glioblastoma (GBM) causes recurrence. However, targeting residual cells has failed, due to their inaccessibility and our lack of understanding of their survival mechanisms to radiation therapy. Here we deciphered a residual cell–specific survival mechanism essential for GBM relapse. Methods Therapy resistant residual (RR) cells were captured from primary patient samples and cell line models mimicking clinical scenario of radiation resistance. Molecular signaling of resistance in RR cells was identified using RNA sequencing, genetic and pharmacological perturbations, overexpression systems, and molecular and biochemical assays. Findings were validated in patient samples and an orthotopic mouse model. Results RR cells form more aggressive tumors than the parental cells in an orthotopic mouse model. Upon radiation-induced damage, RR cells preferentially activated a nonhomologous end joining (NHEJ) repair pathway, upregulating Ku80 and Artemis while downregulating meiotic recombination 11 (Mre11) at protein but not RNA levels. Mechanistically, RR cells upregulate the Su(var)3-9/enhancer-of-zeste/trithorax (SET) domain and mariner transposase fusion gene (SETMAR), mediating high levels of H3K36me2 and global euchromatization. High H3K36me2 leads to efficiently recruiting NHEJ proteins. Conditional knockdown of SETMAR in RR cells induced irreversible senescence partly mediated by reduced H3K36me2. RR cells expressing mutant H3K36A could not retain Ku80 at double-strand breaks, thus compromising NHEJ repair, leading to apoptosis and abrogation of tumorigenicity in vitro and in vivo. Pharmacological inhibition of the NHEJ pathway phenocopied H3K36 mutation effect, confirming dependency of RR cells on the NHEJ pathway for their survival. Conclusions We demonstrate that the SETMAR-NHEJ regulatory axis is essential for the survival of clinically relevant radiation RR cells, abrogation of which prevents recurrence in GBM.

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