DJ-1 has been reported as a gene linked to early onset familial Parkinson's disease, and is functionally involved in transcriptional regulation and oxidative stress-induced cell death. To understand the role of DJ-1 in cellular stress, this study investigated DJ-1's effect on stress-activated protein kinase signaling and H(2)O(2)-induced activation of apoptosis signal-regulating kinase 1 (ASK1). According to the results, the overexpression of DJ-1 inhibited H(2)O(2)-induced activation of ASK1 as well as the activation of downstream kinases in the p38 mitogen-activated protein kinase (MAPK) signaling cascade. The results of both in vivo binding and kinase studies have revealed that ASK1 is the direct target of DJ-1, whereas it has shown no effect on either MKK3 or p38. DJ-1 blocked both the homo-oligomerization of ASK1 and inhibited ASK1 activity. Taken together, our data strongly suggest that DJ-1, by directly inhibiting ASK1, may act as a negative regulator in ASK1 signaling cascades.

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Autophagy is a highly conserved mechanism that degrades long-lived proteins and dysfunctional organelles, and contributes to cell fate. In this study, autophagy attenuates Notch1 signaling by degrading the Notch1 intracellular domain (Notch1-IC). Nutrient-deprivation promotes Notch1-IC phosphorylation by MEKK1 and phosphorylated Notch1-IC is recognized by Fbw7 E3 ligase. The ubiquitination of Notch1-IC by Fbw7 is essential for the interaction between Notch1-IC and p62 and for the formation of aggregates. Inhibition of Notch1 signaling prevents the transformation of breast cancer cells, tumor progression, and metastasis. The expression of Notch1 and p62 is inversely correlated with Beclin1 expression in human breast cancer patients. These results show that autophagy inhibits Notch1 signaling by promoting Notch1-IC degradation and therefore plays a role in tumor suppression.

Intestinal failure-associated liver disease (IFALD) is a serious complication of parenteral nutrition (PN). Studies have shown that the amount and content of intravenous lipid emulsions (LEs) used is closely related to the development of IFALD. We report 2 cases of IFALD reversed by switching from a combination lipid emulsion containing fish oil to fish oil monotherapy (Omegaven; Fresenius Kabi Austria Gmbh, Graz, Austria). Patients initially received PN containing SMOFlipid 20% (SMOF; Fresenius Kabi Austria Gmbh, Graz, Austria), 2.0-3.0 g/kg/d, over 24 hours. When IFALD developed, LE was switched from SMOF to Omegaven starting at 1.0 g/kg/d over 12 hours. Case 1 was an 11-month-old girl with a diagnosis of extensive Hirschsprung disease up to the proximal jejunum. She developed direct bilirubinemia at 3 months, and the patient's LE was switched to Omegaven. A decrease in direct bilirubin was observed after 60 days on Omegaven, and IFALD was completely resolved after 90 days. Case 2 was a 1-month-old boy with a history of gastroschisis diagnosed with megacystis microcolon intestinal hypoperistalsis syndrome. He could not tolerate any oral feeds and was kept on full PN. He had elevated direct bilirubin and developed IFALD since 5 weeks. Omegaven treatment was initiated at 5 months. Direct bilirubin rose to 8 mg/dL during the first month on Omegaven. Then a gradual decrease in direct bilirubin was observed, and after 5 months on Omegaven, IFALD was completely resolved. In conclusion, 2 infants with advanced IFALD showed reversal of cholestasis by switching from SMOF to Omegaven monotherapy.