Aquaporins Danielle Filer, RN, BSN, SRNA - PowerPoint Presentation

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Aquaporins

Danielle Filer, RN, BSN, SRNAYork College of PennsylvaniaGraduate program in Nursing

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Objectives

Understand the structure and function of aquaporins in transporting water across cell membranesExplain the action of aquaporins in reabsorbing water in the kidneyDescribe the function of aquaporins in the brain, heart, and GI tractDiscuss the function of aquaporins in gas and glycerin transportUnderstand the anesthetic implication of aquaporins

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The AQP

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Wang

& Tajkhorshid (2007) Molecular Mechanisms of AQP 1-3 (p 1510S)

Structure and Function

FunctionMaintain homeostasisMaintain cellular integrityMaintain osmoregulationRepel cations

StructureHomotetramer 6 transmembrane alpha helices, 2 half helices, 5 connecting loopsSelectivity FilterNPA-motif

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AQPs in the Kidney

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Day et. al. (2013) Human AQP: Regulators of transcellular water flow (p 1498)

Kortenoeven & Fenton (2013) Renal AQP and water balance disorders (p 1534)

AQP outside the Kidney

BrainAQP4 AstrocytesHeartAQP1AQp4GI tractAQP1AQP3&4AQP8&9

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Day et. al. (2013) Human AQP: Regulators of transcellular water flow (p 1493)

AQPs Transport CO2 and NO

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Herrera & Garvin (2011) AQP and gas channels (p 626)

Herrera & Garvin (2011) AQP and gas channels (p 627)

AQPs Transport Glycerol

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Verkman (2005) unexpected cellular roles of AQP (p 3229)

Anesthesia Implications

Importance in ACE inhibitor induced refractory hypotension Maintaining appropriate circulating blood volume

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To Summarize:

AQPs are essential to maintaining homeostasis and appropriate water volumeStructure and vesicle translocation capabilities allow for specificitySome AQPs do more than transport waterAQP are essential to the anesthetist due to their role in regulating blood volumeWithout AQPs, organisms could not maintain an internal environment compatible with life

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Questions?

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Resources

Abramson, J., and Vartanian, A. S. (2013). Watch water flow. Science, 340(6138), 1294-1295. doi: 10.1126/science.1239270  Barrett, L. K., Singer, M., & Clapp, L. (2007). Vasopressin: mechanisms of action on the vasculature in health and in septic shock. Critical Care Medicine, 35(1), 33-40. doi: 10.1097/01.CCM.0000251127.45385.CD Conner, M. T., Conner, A. C., Bland, C. E., Taylor, L. H. J., Brown, J. E.P., Parri, H. R., and Bill, R. M. (2012). Rapid aquaporin translocation regulates cellular water flow: mechanism of hypotonicity-induced subcellular localization of aquaporin 1 water channel. The Journal Of Biological Chemistry, 278(14), 11516–11525. doi: DOI 10.1074/jbc.M111.329219  Day, R. E., Kitchen, P., Owen, D. S., Bland, C., Marshall, L., Conner, A. C., Bill, R. M., Conner, M. T. (2013). Human aquaporins: regulators of transcellular water flow. Biochimica et Biophysica Acta. 1840(5), 1492-1506. doi: 1016/j.bbagen.2013.09.033 Eriksson, U. K., Fischer, G., Friemann, R., Enkavi, G., Tajhorshid E., Neutze, R. (2013). Subangstrom resolution x-ray structure details aquaporin-water interactions. Science. 340(6138), 1346-1349. doi: 10.1126/science.1234306

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Resources

Guyton, A. C., and Hall, J. E. (2011). Urine formation by the kidneys: II. Tubular reabsorption and secretion. In Guyton and Hall (Ed 11), Textbook of Medical Physiology (pp 339, 345, 383, 820). Philadelphia, PA: Saunders Herrera, M., & Garvin, J. L. (2011). Aquaporins as gas channels. European Journal of Physiology, 642, 623-630. doi: DOI 10.1007/s00424-011-1002-x Jarius, S., & Wildemann, B. (2012). The case of the marquis de caucan (1804): an early account of visual loss associated with spinal cord inflammation. Journal of Neurology, 259: 1354-1357. doi: 10.1007/s00415-011-6355-8 Kortenoeven, M. L. A., Fenton, R. A. (2013). Renal aquaporins and water balance disorders. Biochimica et Biophysica Acta. 1840(5), 1533-1549. doi: 10.1016/j.bbagen.2013.12.002 Lee, J., Yoo, K., Kim, S. W., Jung, K. H., Ma, S. K., Lee, Y. K., Kim, W., Kim, J., and Choi, K. C. (2006). Decreased expression of aquaporin water channels in denervated rat kidneys. Nephron Physiology. 103, 170-178. doi: 10.1159/000092918

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Resources

Matsuzaki, T., Suzuki, T., Koyama, H., Tanaka, S., and Takata, K. (1999). Water channel protein AQP3 is present in epithelia exposed to the environment of possible water loss. The Journal of Histochemistry & Cytochemistry. 47(10), 1257-1286Rutkovskiy, A., Stensløkken, K. R., Mariero, L. H., Skrbic, B., Amiry-Moghaddam, M., Hillestad, V., Valen, G., Perreault, M., Ottersen, O. P., Gullestad, L., Dahl, C. P., Vaage, J. (2012). Aquaporin-4 in the heart: expression, regulation and functional role in ischemia. Basic Research in Cardiology, 107(280). doi: 10.1007/s00395-012-0280-6 Sasaki, S., Uchida, S., Kuwahara, M., Fushimi, K., and Marumo, F. (1997). Aquaporins and ion conductance. Science. 275(5305), 1490-1492. Schrier, R. W. (2006). Water and sodium retention in edematous disorders: role of vasopressin and aldosterone. The American Journal Of Medicine, 119(7A), S47-S53. doi: 10.1016/j.amjmed.2006.05.007 Thoma, A. (2013). Pathophysiology and management of angiotensin-converting enzyme inhibitor-associated refractory hypotension during the perioperative period. AANA Journal, 81(2), 133-140. Retrieved from aanajournal.com/aanajournalonline

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Verkman, A. S., Anderson, M. O., and Papadopoulos. M. C. (2014). Aquaporins: important but elusive drug targets. Nature Reviews Drug Discovery, 13, 259-277. doi:10.1038/nrd4226  Verkman, A. S. (2013). Aquaporins. Current Biology. 23(2), R52-R55. doi: 10.1016/j.cub.2012.11.025 Verkman, A. S. (2011). Aquaporins at a glance. Journal of Cell Science. 124, 2107-2112. doi: 10.1242/jcs.079467 Verkman, A. S. (2005). More than just water channels: unexpected cellular roles of aquaporins. Journal of Cell Science. 118, 3225-3232. doi: 10.1242/jcs.02519 Wang, Y and Tajkhorshid, E. (2007). Molecular Mechanisms of Conduction and Selectivity in Aquaporin Water Channels 1-3. The Journal of Nutrition. 137, 1509S–1515S.

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Resources