Human Kv1.3 Stable Cell Line

Kv1.3 is a voltage-gated K⁺ channel that contributes to the delayed rectifier K⁺ current in a range of cell types. Kv1.3 is potently blocked by the peptides ShK, charybdotoxin and margatoxin and small molecules such as PAP-1.Selective blockers of Kv1.3 inhibit calcium signaling, cytokine production and proliferation of T lymphocytes in vitro and ameliorate disease in animal models of multiple sclerosis, rheumatoid arthritis, type 1 diabetes mellitus and contact dermatitis.

Essen Bioscience and OriGene have co-developed a stable human Kv1.3 expressing cell line in human Chinese Hamster Lung (CHL) cells for various functional screening assays.

Figure 1: In a SYBR green qPCR experiment, specific over-expression of KCN3A was determined using gene specific primers. Data are shown as fold over-expression after normalization against GAPDH

Figure 2: Current-voltage relationship for hKv1.3 channels stably expressed in CHL cells (A); filled circles - CHL-Kv1.3, filled triangles - CHL-wild type cells. Representative recordings from CHL-Kv1.3 (B) and CHL-wild type cells (C). Experiments were conducted from a holding potential of -80mV. The depolarising step length was 200ms.

Figure 3: Expression profile: outward K⁺ currents of >0.6 nA were observed in 337 of 341 cells (99%), with a mean amplitude of 2.60 ± 0.132 nA (n=341; mean ± S.D.). The peak current in each cell, evoked from a depolarising pulse to +40 mV, was divided into 0.2 nA bins to create the population histogram

Figure 4: Summary pharmacology of hKv1.3-CHL cell line. Voltage-clamp recordings were made using repeated gating steps, V_h -80mV, V_step +40mV, 1 Hz, pulse duration 250ms. Control traces in black, test compounds in red. IC₅₀ values were obtained by fitting concentration-response curves to values for inhibition of the 1st (peak and sustained) and 5th pulse in the train (µM, shown in table). Use-dependent and open channel block can be assessed within this protocol.