Macrophage-derived IL-1α promotes sterile inflammation in a mouse model of acetaminophen hepatotoxicity

The metabolic intermediate of acetaminophen(APAP)can cause severe hepatocyte necrosis,which triggers aberrant immune activation of liver non-parenchymal cells(NPC).Overzealous hepatic inflammation determines the morbidity and mortality of APAP-induced liver injury(AILI).Interleukin-1 receptor(IL-1R)signaling has been shown to play a critical role in various inflammatory conditions,but its precise role and underlying mechanism in AILI remain debatable.Herein,we show that NLRP3 inflammasome activation of IL-1βis dispensable to AILI,whereas IL-1α,the other ligand of IL-1R1,accounts for hepatic injury by a lethal dose of APAP.Furthermore,Kupffer cells function as a major source of activated IL-1αin the liver,which is activated by damaged hepatocytes through TLR4/MyD88 signaling.Finally,IL-1αis able to chemoattract and activate CD11b^(+)Gr-1^(+) myeloid cells,mostly neutrophils and inflammatory monocytes,to amplify deteriorated inflammation in the lesion.Therefore,this work identifies that MyD88-dependent activation of IL-1αin Kupffer cells plays a central role in the immunopathogenesis of AILI and implicates that IL-1αis a promising therapeutic target for AILI treatment.

Maintenance of human embryonic stem cells on gelatin

Matrigel is routinely used as a coating material in the feeder-free culture system of human embryonic stem cells (hESCs). However, matrigel is costive and inconvenient to use. In this study, the possibility of using gelatin as an alternative coating material was investigated. The results showed that, after trypsinization, hESCs were maintained undifferentiated on gelatin. These hESCs expressed pluripotent markers, formed teratoma and maintained a normal karyotype. As measured at passage 10, the hESCs expressed a high level of Oct4 on both gelatin and Matrigel. hESCs growing on gelatin formed AP-positive colonies in similar size and number to those growing on Matrigel (P > 0.05). Moreover, hESCs growing on gelatin contained a comparable percentage of SSEA-4-positive cells to those growing on Matrigel (95.1% vs.94.3%, P > 0.05). H-1 hESCs were maintained undifferentiated on gelatin for 20 passages and remained the stable normal karyotype. This gelatin-based culture protocol may allow us to propagate hESCs in large scale, with less cost.

Effects of metal ions on recombinant calcineurin A subunit

Effects of metal ions on activities and solution conformations of calcineurin A subunit have been examined. The ability of several metal ions to activate calcineurin A has been tested with Ni2+】Mn2+】Mg2+/Ca2+. The corresponding CD spectra and intrinsic fluorescent emission spectra show that calcineurin A exists in different metal ion-dependent conformation states. Effects of the different concentritions of Ni2+ on activities and solution conformations of calcineurin A have been tested too. Results indicate that effects of these metal ions to activate calcineurin are due to their conformational changes.

RNF152, a novel lysosome localized E3 ligase with pro-apoptotic activities

RING finger protein 152(RNF152)is a novel RING finger protein and has not been well characterized.We report here that RNF152 is a canonical RING finger protein and has E3 ligase activity.It is polyubiqitinated partly through Lys-48-linked ubiquitin chains in vivo and this phenomenon is dependent on its RING finger domain and transmembrane domain.RNF152 is localized in lysosomes and co-localized with LAMP3,a lysosome marker.Moreover,over-expression of RNF152 in Hela cells induces apoptosis.These results suggest that RNF152 is a lysosome localized E3 ligase with pro-apoptotic activities.It is the first E3 ligase identified so far that is involved in lysosome-related apoptosis.