Publications by authors named "Young Mook Lee"

Activated caspases play a central role in the execution of apoptosis by cleaving endogenous substrates. Here, we developed a high throughput screening method to identify novel substrates for caspase-3 in a neuronal cell line. Critical steps in our strategy consist of two-dimensional electrophoresis-based protein separation and in vitro caspase-3 incubation of immobilized proteins to sort out direct substrates.

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Nerve function recovery is a major technical challenge in the rehabilitation of patients suffering from severe neuropathies. Facilitating functional recovery requires the creation of a growth-permissive environment that directs the extension and myelination of surviving neurons. To this end, an electrospun nanofiber scaffold composed of arginine-glycine-aspartate-modified poly(serinol hexamethylene urea)-blend-poly-ε-caprolactone (PSHU-RGD/PCL) has been employed.

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Calpains are a family of calcium-dependent cysteine proteases that are ubiquitously expressed in mammals and play critical roles in neuronal death by catalyzing substrate proteolysis. Here, we developed two-dimensional gel electrophoresis-based protease proteomics to identify putative calpain substrates. To accomplish this, cellular lysates from neuronal cells were first separated by pI, and the immobilized sample on a gel strip was incubated with a recombinant calpain and separated by molecular weight.

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Parkinson's disease (PD) is characterized by the selective loss of midbrain dopamine neurons. Neural transplantation with fetal dopamine neurons can be an effective therapy for patients with PD, but recovery of human fetal cells is difficult. Scarcity of tissue has limited clinical application to a small number of research subjects worldwide.

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Symptoms of Parkinson's disease have been improved by transplantation of fetal dopamine neurons recovered from aborted fetal tissue, but tissue recovery is difficult. Human embryonic stem cells may provide unlimited cells for transplantation if they can be converted to dopamine neurons and survive transplantation into brain. We have found that the bone morphogenic protein antagonist Noggin increased the number of dopamine neurons generated in vitro from human and mouse embryonic stem cells differentiated on mouse PA6 stromal cells.

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The aim of this study was to investigate changes in protein profiles during the early phase of dopaminergic neuronal death using two-dimensional gel electrophoresis in conjunction with mass spectrometry. Several protein spots were identified whose expression was significantly altered following treatment of MN9D dopaminergic neuronal cells with 6-hydroxydopamine (6-OHDA). In particular, we detected oxidative modification of thioredoxin-dependent peroxidases (peroxiredoxins; PRX) in treated MN9D cells.

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We have utilized integrated technologies including separation of proteins by 2-dimensional (2-D) gel electrophoresis and identification of proteins by matrix assisted laser desorption/ionizing time of flight (MALDI-TOF) mass spectrometry to examine an array of proteins that are regulated following treatment with neurotoxin. In essence, total cellular lysates harvested from MN9D dopaminergic neuronal cells treated with 6-hydroxydopamine (6-OHDA) for various time periods were subjected to 2-D gel separation followed by an analysis of the protein spots separated. Among the several protein spots that appeared to be either up- or down-regulated following 6-OHDA treatment, MALDI-TOF mass spectrometry revealed that an ER chaperone protein, calreticulin, was upregulated in a time-dependent manner.

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