Research Projects
- Chemical biology of ion channels (funded by DFG)
PI: Thomas Budde
Doctoral researchers: Elif Karabatak, Afsaneh Labbaf, Nicole Rychlik
Collaborators: Members of GRK 2515/1 “Chembion”.
Weblink: https://www.uni-muenster.de/ChemBion/
The function and dysfunction of hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels in the thalamocortical system is investigated by using new subtype-specific drugs:
First, newly synthesized compounds are screened in cell lines expressing one of the HCN channel subtypes (HCN1-4) cloned from human or rodent DNA. The degree of current reduction is compared to the effect of well-known channel blockers, like EC18. Therefore, the current carried by HCN channels, termed Ih, is activated by membrane hyperpolarization in cultured cells and the compound effect is assed. Thereafter, selected compounds are tested on native Ih in thalamic and cortical neurons.
Whole-cell patch clamp recording showing Ih reduction in a thalamocortical (TC) neuron in a brain slice by 10 µM of the HCN4-selective blocker EC18. Ih in the presence (red line) and absence (black line) of the drug was elicited by a hyperpolarizing voltage step to -120 mV.
Characterization of new tool compounds modulating KCNQ (KV7) channels:
First, a cell line expressing the neuronal KCNQ subtype combination (KCNQ2/3) was generated using human DNA (Fig. 2). Next, the current carried by KCNQ2/3 channels, termed IM, is activated by membrane depolarization in cultured cells and the effect of well-known channel modulators (activator: retigabine; inhibitor: XE-991) was assed (Fig. 2). Thereafter, new lipidomimetics of cholesterol and PIP2 synthesized using click-chemistry will be tested.
Whole-cell patch clamp recordings of IM in transfected HEK-293FT cells showing currents elicited by voltage steps to +40 mV (black traces). The current at -80 mV is shown in gray. IM is enhanced by retigabine (RET; purple trace) and inhibited by XE-991 (blue trace). The inset shows a typical transfected cell with the patch pipette approaching from the right side.
