Jin Hyup Lee

Recently, we demonstrated that the control of cytosolic and mitochondrial redox balance and oxidative damage is one of the primary functions of NADP+-dependent isocitrate dehydrogenase (ICDH) by supplying NADPH for antioxidant systems. We investigated whether the ICDH would be a vulnerable target of peroxynitrite anion (ONOO-) as a purified enzyme, in intact cells, and in liver mitochondria from ethanol-fed rats. Synthetic peroxynitrite and 3-morpholinosydnomine N-ethylcarbamide (SIN-1), a perox

In mice and humans the circadian rhythm of many biochemical reactions, physiology, and behavior is generated by a transcriptional-translation feedback loop (TTFL) made up of the so-called core clock genes/proteins. The circadian system interfaces with most signaling pathways including those involved in cell proliferation and inflammation. Cryptochrome (CRY) is a core clock protein that plays an essential role in the repressive arm of the TTFL. It was recently reported that mutation of CRY in p53

Ionizing radiation induces the production of reactive oxygen species, which play an important causative role in apoptotic cell death. By supplying NADPH for antioxidant systems, we recently demonstrated that the control of mitochondrial redox balance and the cellular defense against oxidative damage are some of the primary functions of mitochondrial NADP(+)-dependent isocitrate dehydrogenase (IDPm). In this study, we demonstrate that modulation of IDPm activity in U937 cells regulates ionizing r

The circadian clock in mammalian organisms is generated by a transcription-translation feedback loop that controls many biochemical pathways at the cellular level and physiology and behavior at the organismal level. Cryptochrome (Cry) is a key protein in the negative arm of the transcription-translation feedback loop. It has been found that Cry mutation in cells with p53-null genotype increased their sensitivity to apoptosis by genotoxic agents. Here we show that this increased sensitivity is du

The main feedback loop driving circadian rhythm in mice is controlled, in part, by the genes encoding the cryptochromes Cry1 and Cry2. Targeted mutation of both Cry1 and Cry2 delay the early onset of tumor formation in p53-null mutant mice. Furthermore, Ras-transformed p53- and Cry-null mouse skin fibroblasts are more sensitive than p53 mutants to apoptotic cell death initiated by agents that activate either the intrinsic or the extrinsic apoptosis pathways. Here, we investigated the effect of C

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by the loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) and its pathogenesis is under intense investigation. Substantial evidence indicates that mitochondrial dysfunction and oxidative stress play central roles in the pathophysiology of PD, through activation of mitochondria-dependent apoptotic molecular pathways. Several mitochondrial internal regulating factors act to maintain mitochondr

Inflammatory bowel disease (IBD) is a group of chronic, relapsing, immunological, inflammatory disorders of the gastrointestinal tract including ulcerative colitis (UC) and Crohn's disease (CD). It has been reported that UC, which is studied using a dextran sodium sulfate (DSS)-induced colitis model, is associated with the production of reactive oxygen species (ROS) and the apoptosis of intestine epithelial cells (IEC). Mitochondrial NADP⁺-dependent isocitrate dehydrogenase (IDH2) has

Limited studies reported mechanisms by which microRNAs (miRNA) are interlinked in the etiology of fructose-induced non-alcoholic fatty liver disease (NAFLD). Here, we aimed to investigate the significance of miRNAs in fructose-induced NAFLD pathogenesis through unbiased approaches. In experiment I, C57BL/6N mice were fed either water or 34% fructose for six weeks ad libitum. In experiment II, time course effects of fructose intervention were monitored using the same conditions; mice were killed