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10th International Congress "Cell Volume Regulation: Novel Therapeutic Targets and Pharmacological Approaches"
REDOX SIGNALING, APOPTOTIC VOLUME DECREASE AND NEURONAL CELL DEATH Franco, R.
Redox Biology Center, School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, USA
Oxidative stress is involved in the regulation of cell death signaling cascades, but the molecular mechanisms involved remain unclear. GSH is the most abundant low molecular weight thiol antioxidant defense in the cell. We have previously demonstrated that GSH depletion parallels apoptotic volume decrease and precedes the activation of cell death signaling [1-3]. Here, we aim to demonstrate the different mechanisms by which alterations in intracellular GSH homeostasis (transport and metabolism) regulate neuronal cell death progression in experimental Parkinson's disease models. Dopaminergic cell death was induced by environmental/mitochondrial toxins, and overexpression of wild type or mutant (A53T) a-synuclein. Dopaminergic cell death and apoptotic volume decrease were associated with a decrease in total GSH content and an increase oxidative stress. Using novel genetically encoded redox sensors (roGFP) we identified the alterations in redox homeostasis in both mitochondria and cytosolic compartments [4]. GSH depletion was also paralleled by alterations in protein-cysteine-bound GSH (protein glutathionylation), and we demonstrated a signaling role
for this oxidative post-translational modification in dopaminergic cell death. Thiol-oxidoreductases exerted protective effects against neuronal cell death by regulating thiol-redox homeostasis within the cell [5]. Our research has contributed significantly to the understanding of the distinct mechanisms by which GSH depletion (transport or metabolism) regulates cell death progression by acting as a redox signaling transducer [6, 7].
References
1. Franco, R., et al. J. Biol. Chem., 2008, 283 (52), pp. 3607136087.
2. Franco, R., et al. J. Biol. Chem., 2007, 282 (42), pp. 3045230465.
3. Franco, R., et al. J. Biol. Chem., 2006, 281 (40), pp. 2954229557.
4. Rodriguez-Rocha, H., et al. Free Radic. Biol. Med., 2013.
5. Rodriguez-Rocha, H., et al. Antioxid Redox Signal, 2012, 17 (12), pp. 1676-1693.
6. Franco, R., et al. Cell Death. Differ., 2009, 16 (10), pp. 1303-1314.
7. Franco, R., et al. Antioxid Redox Signal., 2012, 17 (12), pp. 1694-1713.
INTRACELLULAR PROTEINS WHICH REGULATE K-CL COTRANSPORTER ACTIVITY MAY SERVE AS NOVEL TARGETS FOR ANTI-CANCER THERAPEUTICS
Gagnon, K.B.
Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK, Canada
The anaplastic and invasiveness nature of high-grade gliomas involves a synchronized reorganization of the cyto-skeleton, membrane recycling, and focal adhesion to the extracellular matrix. These cellular processes are aided by the obligatory water movement which occurs when inorganic ions are transported across the plasma membrane. In a previous study, the presence of Na+-independent K-Cl cotransporter (KCC) isoforms suggested that these membrane proteins had a role in glioma cell motility [1]. Utilizing a rat glioblastoma cell line which shares many characteristics of high-grade gliomas [2], RT-PCR analysis identified RNA expression of: (1) with-no-lysine (WNK) kinases; (2) oxidative stress response (OSR1) kinase; (3) Ste20-related proline-alanine rich kinase (SPAK); (4) protein phosphatase 1 (PP1); and (5) apoptosis-associated tyrosine kinase (AATYK1). Each of these intracellular signaling
molecules has been shown to partially regulate cotransporter activity. Although K+ influx in Xenopus laevis oocytes co-injected with KCC1 and AATYK1 cRNA was not different under isosmotic conditions, co-injection of KCC3 and AATYK1 cRNA increased isosmotic K+ influx to levels observed under hyposmotic conditions. These results suggest that differential expression of specific regulatory proteins might have a role in cotransporter activity, and in turn, possibly glioblastoma cell motility.
References
1. Gagnon, K.B. High-grade glioma motility reduced by genetic knockdown of KCC3. Cell Physiol Biochem., 2012, 30 (2), pp. 466-476.
2. Benda, P., Lightbody, J., Sato, G., Levine, L., and Sweet, W. Differentiated rat glial cell strain in tissue culture. Science, 1968, 161, pp. 370-371.
Бюллетень сибирской медицины, 2013, том 12, № 4, с. 24-68
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