Peningkatan Konduktansi Maksimal Ion Kalium Setelah Pemberian 7-Ketokolesterol pada sel PC-12 SecaraIn vitro
Authors
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Indra Kusuma
Magister Program of Biomedical Sciences,Faculty of Medicine, University ofIndonesia
Department of Physiology, Faculty of Medicine, YARSIUniversity, Jakarta
Keywords:
7-ketokolesterol, Kanal Kv, Lipid raft, Patch clampAbstract
Stroke menyebabkan kondisi hipoksia-iskemia yang menimbulkan berbagaikerusakan. Perubahan neurokimia otak pada stroke menyebabkan oksidasikolesterol. Produk oksidasi kolesterol yaitu 7-ketokolesterol diketahui mengubahkomposisi lipid raft, sifat protein membran dan meningkatkan eksositosisneurotransmitter. Kanal Kv berperan pada terminasi eksositosis danmempertahankan keseimbangan ionik sel saraf. Pemberian 7-ketolesterol padasel PC-12 bertujuanmelihat respon kanal Kv. Perekaman patch clamp dilakukandengan tehnik whole-cell secara voltage clamp. Hasil eksperimen terekamkenaikan arus listrik (p<0.05) pada potensial membran negatif, penurunanreversal potensial (p>0.05) dan peningkatan konduktansi maksimal ion kalium(p<0.05). Hasil eksperimen berupa perubahan konduktansi maksimalmenunjukkan pengaruh 7-ketokolesterol pada kinetika dan fungsi kanal Kv yangdiperkirakan sebagai akibat perubahan interaksi lipid-protein pada lipid raft.Pada konteks stroke respon kanal Kv turut berkontribusi pada prosesneurotoksisitas yang berujung pada kematian sel.Stroke menyebabkan kondisi hipoksia-iskemia yang menimbulkan berbagaikerusakan. Perubahan neurokimia otak pada stroke menyebabkan oksidasikolesterol. Produk oksidasi kolesterol yaitu 7-ketokolesterol diketahui mengubahkomposisi lipid raft, sifat protein membran dan meningkatkan eksositosisneurotransmitter. Kanal Kv berperan pada terminasi eksositosis danmempertahankan keseimbangan ionik sel saraf. Pemberian 7-ketolesterol padasel PC-12 bertujuanmelihat respon kanal Kv. Perekaman patch clamp dilakukandengan tehnik whole-cell secara voltage clamp. Hasil eksperimen terekamkenaikan arus listrik (p<0.05) pada potensial membran negatif, penurunanreversal potensial (p>0.05) dan peningkatan konduktansi maksimal ion kalium(p<0.05). Hasil eksperimen berupa perubahan konduktansi maksimalmenunjukkan pengaruh 7-ketokolesterol pada kinetika dan fungsi kanal Kv yangdiperkirakan sebagai akibat perubahan interaksi lipid-protein pada lipid raft.Pada konteks stroke respon kanal Kv turut berkontribusi pada prosesneurotoksisitas yang berujung pada kematian sel.References
Berthier A, Lemaire-Ewing S, Prunet C, Montage T, Vejux A, Pais de Barros J, Monier S, Gambert P, Lizard G & DN 2005. 7-ketocholesterol-inducec apoptosis: Involvementof several pro-apoptotic but also anti-apoptotic pathway calcium-dependent transduction pathway. The FEBS Journal 272, h.30933104.
Dart C 2010. Lipid microdomain and the regulation of channel function.J Physiol588,h.3169-3178.
Girao H, Catarino S & Pereira P 2004. 7-Ketocholesterol modulates intercelullar comunication through gapjunction in bovine lens epithelial cells. Cell Communication and Signalling2,h1-10.
Guyton AC & Hall JE 2006. Textbook of Medical Physiology. Elsevier Saunders, Philadelphia.
Kim JH, Jittiwat J, Ong WY, Farooqui AA & Jennert AM 2010. Changes in cholesterol biosynthetic and transport pathway after excitotoxicity. Journal of Neurochemistry,h34-41.
Kornreich BG 2007. The patch clamp technique: Principles and technical considerations. Journal of veterinary cardiology9,h.25-37.
Larrayoz IM, HuangJ-D, Lee JW, Pascual I & Rodriguez IR 2010. 7-ketocholestrol- incuded inflamation : involvement of multiple kinase signalling pathways via NFkB but independently of reactive oxygen
species formation. Invest Ophtamol Vis Sci 51, h49424955.
Leung YM KE, Ng B, Kang Y, Gaisano HY 2007. SNAREing voltage-gated K+ and ATP-sensitive K+channels: Tunning beta-cell excitability with
syntaxin-1A and other exocytotic proteins. Endocrine reviews28,h653-663.
Ma MT, Zhang J, Farooqui AA, Chen P & Ong WY 2010. Effects of cholesterol oxidation products on exocytosis.Neurosciense Letters476,36-41.
Neekhra A, Luthra S, Chwa M, Seigel G, Gramajo AI, Kuppermann BD & MC K 2007. Caspase-8,-12,-3 activation by 7-ketocholesterol in retinal
neurosensory cells. Invest OphtamolVis Sci57,h13621367.
Ong WY, Kim JH, He X, Chen P, Farooqui AA & Jenner AM 2010. Changes in Brain Cholesterol Metabolome after excitotoxicity. Mol Neurobiol41,h.299-313.
Sperelakis N 2001. Cell physiology sourcebook: A molecular approach 3rd. ed. Academic Press.
Torres YP, Morera FJ, Carvacho I & Latorre R 2007. A Marriage of Convenience : Beta subunits and Voltage-dependent K+ Channels. The Journal of BiologicalChemistry282, h.24485-24489.
Tossetti P, Taglietti V &Toselli M 1998. Functional changes in potassium conductances of the human neuroblastoma cell line SH-SY5Y during in vitro differentiation.J Neurophysiol79,h.997-1007.
Westerink RHS & Ewing AG 2008. The PC12 cell as model of neurosecretion. Acta Physiol (Oxf) 192, h.273-285.
Wong W & Schichter LC 2004. Differential recruitment of Kv 1.4 and Kv 4.2 to lipid rafts by PSD-95. The Journal of Biological Chemistry279,h.444-452.
Wylest JP, McMaster CR & Ridgway ND 2002. Vesicleassociated Membrane Protein-associated Protein-A (VAP-A) Interacts with the Oxysterol-binding Protein to Modify Export from the Endoplasmic
Reticulum. The Journal of Biological Chemistry 277, h.29908-29918.
Zheng XY, Zhang HL, Luo Q & Zhu J 2011. Kainic acidinduced neurodegenerative model : Potential and limitation. Journal of Biomedicine and Biotechnology, h.1-10.
