Inhibiting membrane rupture with NINJ1 antibodies limits tissue injury.

Plasma membrane rupture (PMR) in dying cells undergoing pyroptosis or apoptosis requires the cell-surface protein NINJ11. PMR releases pro-inflammatory cytoplasmic molecules, collectively called damage-associated molecular patterns (DAMPs), that activate immune cells. Therefore, inhibiting NINJ1 and PMR may limit the inflammation that is associated with excessive cell death. Here we describe an anti-NINJ1 monoclonal antibody that specifically targets mouse NINJ1 and blocks oligomerization of NINJ1, preventing PMR. Electron microscopy studies showed that this antibody prevents NINJ1 from forming oligomeric filaments. In mice, inhibition of NINJ1 or Ninj1 deficiency ameliorated hepatocellular PMR induced with TNF plus D-galactosamine, concanavalin A, Jo2 anti-Fas agonist antibody or ischaemia-reperfusion injury. Accordingly, serum levels of lactate dehydrogenase, the liver enzymes alanine aminotransaminase and aspartate aminotransferase, and the DAMPs interleukin 18 and HMGB1 were reduced. Moreover, in the liver ischaemia-reperfusion injury model, there was an attendant reduction in neutrophil infiltration. These data indicate that NINJ1 mediates PMR and inflammation in diseases driven by aberrant hepatocellular death.

Combined Treatment of ATRA with Epigenetic Drugs Increases Aggressiveness of Glioma Xenografts.

BACKGROUND/AIM: Recently, anti-tumourigenic effects of all-trans-retinoic-acid (ATRA) on glioblastoma stem cells were demonstrated. Therefore we investigated if these beneficial effects could be enhanced by co-medication with epigenetic drugs such as the histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) or the DNA-methyltransferase inhibitor 5-aza-2'deoxycytidine (5-AZA). MATERIALS AND METHODS: Glioma stem cell xenografts were treated for 42 days with ATRA plus SAHA or ATRA plus 5-AZA or the correspondent monotherapies. Tumour sizes, histological features, proliferation and apoptosis rates were assessed. RESULTS: Neither SAHA nor 5-AZA were able to enhance the anti-tumourigenic effect of ATRA. Instead, tumours became more aggressive. Combination of ATRA plus 5-AZA increased tumour size (p<0.05) and induced more frequent and larger necroses (p<0.05) and tumours were more invasive (p<0.05) in comparison to controls. A similar trend was observed for the combination of ATRA plus SAHA. CONCLUSION: Combining ATRA with epigenetic drug therapies led to the unwanted opposite effect and increased aggressiveness of glioma xenografts, arguing against future clinical applications of such combinations.