Calcium is the most universal carrier of biological signals. It modulates cell life from its origin at fertilization to its end in the apoptotic process. Cells need Ca2+ to correctly carry out most of their important functions. At this point, Ca2+ permeable transient receptor potential channels (TRPs) play a crucial role in cellular signaling in all kind of excitable cells. They also play a role in non-excitable (ocular) cells and (ocular) tumor cells. They also play a role in the development of therapies against diseases (e.g. TRPV4 against covid-19).

The participants of the course will acquire knowledge about experimental ophthalmology with clinical aspects using high sensitive functional assays such as fluorescence calcium imaging and (planar) patch-clamping. Videos of these methods will be shown. More specifically, students will learn the function of Ca2+ binding proteins, Ca2+ homeostasis, regulation of intracellular Ca2+ compartmentalization, Ca2+ channels and pumps, identification and function of TRPs (e.g. Ca2+ signal and cell proliferation in context with TRPs). Furthermore, students will be able to understand some relevant contributions of the TRPs and their typical characteristics in context with ocular (tumor) diseases (e.g. dry eye syndrome, pterygium, uveal melanoma). Moreover, the students will understand how certain TRPs can be identified and the relevance of the aforementioned methods in electrophysiology. Finally, the students will learn how to transfer this knowledge to interdisciplinary topics between medical neurosciences and experimental ophthalmology as well as general medicine..

The lecture may be assigned to the following weekly subunits (with revision books, active attendance)
(e.g. always approx. 40 min presentation and 5 min active discussion of the students):

1. History and evolution of calcium biochemistry
2. Ca²⁺ homeostasis, channels and pumps
3. TRP channels and methods for their electrophysiological detection
4. TRP channels on the eye surface: Relevant for the clinic? TRP channels and covid-19
5. Experimental ophthalmology and daily clinic
6. Scientific practice in general and in electrophysiology, virtual lab tour if required

The journal club will be scheduled after the lecture (ca. 20 min. presentations and discussions)
 

Short and long essay questions about the content of the lecture can be prepared for grading if applicable.
Presentations for Journal Club is scheduled

Mandatory:

• B. Nilius and G. Owsianik. Transient receptor potential channelopathies. Pflugers Arch 460 (2):437-450, 2010.
• Veldhuis, N.A., Poole, D.P., Grace, M., McIntyre, P., and Bunnett, N.W. (2015). The G protein-coupled receptor-transient receptor potential channel axis: molecular insights for targeting disorders of sensation and inflammation. Pharmacol Rev 67(1), 36-73.
• S. Mergler and U. Pleyer. The human corneal endothelium: New insights into electrophysiology and ion channels. Prog.Retin.Eye Res. 26 (4):359-378, 2007.
• Mergler, S., Reinach P.S., et al. (2014). "Temperature-sensitive transient receptor potential channels in corneal tissue layers and cells." Ophthalmic Res 52(3): 151-159.
• Reinach, P. S., Mergler S., et al. (2015). "Polymodal roles of transient receptor potential channels in the control of ocular function." Eye Vis (Lond) 2(1): 5.
• Reinach, P. S., Mergler S., et al. (2016). "Ocular transient receptor potential channel function in health and disease." BMC Ophthalmology BMC Ophthalmol 15 Suppl 1: 153.
• Khajavi, N., Mergler S., et al. (2017). "3-Iodothyronamine, a Novel Endogenous Modulator of Transient Receptor Potential Melastatin 8?" Front Endocrinol (Lausanne) 8: 198.

Further:

• Pamir, E., et al. (2008). "Planar patch-clamp force microscopy on living cells." Ultramicroscopy 108(6): 552-557.
• A. Bruggemann, S. Stoelzle, M. George, J. C. Behrends, and N. Fertig. Microchip technology for automated and parallel patch-clamp recording. Small 2 (7):840-846, 2006.
• Milligan, C. J., et al. (2009). "Robotic multiwell planar patch-clamp for native and primary mammalian cells." Nature Protocols 4(2): 244-255.

Original papers (some suggestions):

• J. Donau, H. Luo, I. Virta, A. Skupin, M. Pushina, J. Loeffler, Haertel, F. V., Das, A., Kurth, T., Gerlach, M., Lindemann, D., Reinach, P. S., Mergler, S., Valtink, M. TRPV4 Stimulation Level Regulates Ca(2+)-Dependent Control of Human Corneal Endothelial Cell Viability and Survival Membranes (Basel) 2022 Vol. 12 Issue 3
• Oronowicz J, Reinhard J, Reinach PS, Ludwiczak S, Luo H, Omar Ba Salem MH, et al. Ascorbate-induced oxidative stress mediates TRP channel activation and cytotoxicity in human etoposide-sensitive and -resistant retinoblastoma cells. Lab Invest. 2021;101(1):70-88.(open access)
• Turan E, Valtink M, Reinach PS, Skupin A, Luo H, Brockmann T, et al. L-carnitine suppresses transient receptor potential vanilloid type 1 activity and myofibroblast transdifferentiation in human corneal keratocytes. Laboratory Investigation. 2021:in press  open access (Please check for publication details in PubMed)
• Walcher L, Budde C, Bohm A, Reinach PS, Dhandapani P, Ljubojevic N, et al. TRPM8 Activation via 3-Iodothyronamine Blunts VEGF-Induced Transactivation of TRPV1 in Human Uveal Melanoma Cells. Front Pharmacol. 2018;9:1234.
• Turker E, Garreis F, Khajavi N, Reinach PS, Joshi P, Brockmann T, et al. Vascular Endothelial Growth Factor (VEGF) Induced Downstream Responses to Transient Receptor Potential Vanilloid 1 (TRPV1) and 3-Iodothyronamine (3-T1AM) in Human Corneal Keratocytes. Front Endocrinol (Lausanne). 2018;9:670..
• S. Mergler, C. Mertens, M. Valtink, P. S. Reinach, V. C. Szekely, N. Slavi, F. Garreis, S. Abdelmessih, E. Turker, G. Fels, and U. Pleyer. Functional significance of thermosensitive transient receptor potential melastatin channel 8 (TRPM8) expression in immortalized human corneal endothelial cells. Exp Eye Res 116:337-349, 2013.
• S. Mergler, R. Derckx, P. S. Reinach, F. Garreis, A. Bohm, L. Schmelzer, S. Skosyrski, N. Ramesh, S. Abdelmessih, O. K. Polat, N. Khajavi, and A. I. Riechardt. Calcium regulation by temperature-sensitive transient receptor potential channels in human uveal melanoma cells. Cell Signal. 26 (1):56-69, 2014.
• Khajavi, N., Mergler, S., et al. (2014). "L-Carnitine Reduces in Human Conjunctival Epithelial Cells Hypertonic-Induced Shrinkage through Interacting with TRPV1 Channels." Cell Physiol Biochem. 34(3): 790-803.
• Khajavi, N., Mergler, S., et al. (2015). "Thyronamine induces TRPM8 channel activation in human conjunctival epithelial cells." Cell Signal 27(2): 315-325.
• Lucius, A., Mergler, S., et al. (2015). "3-Iodothyronamine increases transient receptor potential melastatin channel 8 (TRPM8) activity in immortalized human corneal epithelial cells." Cell Signal 28(3): 136-147.
• Garreis, F., Mergler, S. et al. (2016). "Upregulation of Transient Receptor Potential Vanilloid Type-1 Channel Activity and Ca2+ Influx Dysfunction in Human Pterygial Cells."