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Lovastatin blocks Kv1.3 channel in human T cells: a new mechanism to explain its immunomodulatory properties.

Zhao N, Dong Q, Qian C, Li S, Wu QF, Ding D, Li J, Wang BB, Guo KF, Xie JJ, Cheng X, Liao YH, Du YM - Sci Rep (2015)

Bottom Line: However, 30 μM Lovastatin had no apparent effect on KCa current in human T cells.At last, Mevalonate application only partially reversed the inhibition of Lovastatin on IL-2 secretion, and the siRNA against Kv1.3 also partially reduced this inhibitory effect of Lovastatin.In conclusion, Lovastatin can exert immunodulatory properties through the new mechanism of blocking Kv1.3 channel.

View Article: PubMed Central - PubMed

Affiliation: Research Center of Ion Channelopathy, Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.

ABSTRACT
Lovastatin is a member of Statins, which are beneficial in a lot of immunologic cardiovascular diseases and T cell-mediated autoimmune diseases. Kv1.3 channel plays important roles in the activation and proliferation of T cells, and have become attractive target for immune-related disorders. The present study was designed to examine the block effect of Lovastatin on Kv1.3 channel in human T cells, and to clarify its new immunomodulatory mechanism. We found that Lovastatin inhibited Kv1.3 currents in a concentration- and voltage-dependent manner, and the IC50 for peak, end of the pulse was 39.81 ± 5.11, 6.92 ± 0.95 μM, respectively. Lovastatin also accelerated the decay rate of current inactivation and negatively shifted the steady-state inactivation curves concentration-dependently, without affecting the activation curve. However, 30 μM Lovastatin had no apparent effect on KCa current in human T cells. Furthermore, Lovastatin inhibited Ca(2+) influx, T cell proliferation as well as IL-2 production. The activities of NFAT1 and NF-κB p65/50 were down-regulated by Lovastatin, too. At last, Mevalonate application only partially reversed the inhibition of Lovastatin on IL-2 secretion, and the siRNA against Kv1.3 also partially reduced this inhibitory effect of Lovastatin. In conclusion, Lovastatin can exert immunodulatory properties through the new mechanism of blocking Kv1.3 channel.

No MeSH data available.


Related in: MedlinePlus

Lovastatin blocked Kv1.3 channel currents in human T cells.(A–C) The representative Kv1.3 current traces recorded in Jurkat cells in the absence (A), presence (B) and washout (C) of 30 μM Lovastatin, which were elicited by 300 ms pulses at the test potentials from −80 to + 60 mV in 10 mV steps. (D–F) Representative Kv1.3 traces recorded in PBTCs in the absence (D), presence (E) and washout (F) of 30 μM Lovastatin. (G) Superimposed original Kv1.3 current traces at control, with 10, 30 μM Lovastatin applications, and washout in Jurkat cells. Kv1.3 currents were elicited by the depolarizing step pulses at + 40 mV with the holding potential at −80 mV every 10 s. (H) The dose-response curve of the peak Kv1.3 currents fitted with the Hill equation in Jurkat cells. The summarized data (6 cells) for each concentration are expressed as mean ± SEM. The IC50 and Hill coefficient were 39.81 ± 5.11 μM and 0.56 ± 0.04. (I) The dose-response curve of Kv1.3 currents at the end of the pulse from 6 Jurkat cells were fitted with the Hill equation. The IC50 and Hill coefficient were 6.92 ± 0.95 μM and 0.75 ± 0.06, respectively.
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f1: Lovastatin blocked Kv1.3 channel currents in human T cells.(A–C) The representative Kv1.3 current traces recorded in Jurkat cells in the absence (A), presence (B) and washout (C) of 30 μM Lovastatin, which were elicited by 300 ms pulses at the test potentials from −80 to + 60 mV in 10 mV steps. (D–F) Representative Kv1.3 traces recorded in PBTCs in the absence (D), presence (E) and washout (F) of 30 μM Lovastatin. (G) Superimposed original Kv1.3 current traces at control, with 10, 30 μM Lovastatin applications, and washout in Jurkat cells. Kv1.3 currents were elicited by the depolarizing step pulses at + 40 mV with the holding potential at −80 mV every 10 s. (H) The dose-response curve of the peak Kv1.3 currents fitted with the Hill equation in Jurkat cells. The summarized data (6 cells) for each concentration are expressed as mean ± SEM. The IC50 and Hill coefficient were 39.81 ± 5.11 μM and 0.56 ± 0.04. (I) The dose-response curve of Kv1.3 currents at the end of the pulse from 6 Jurkat cells were fitted with the Hill equation. The IC50 and Hill coefficient were 6.92 ± 0.95 μM and 0.75 ± 0.06, respectively.

Mentions: Jurkat cells were held at −80 mV, and received the test potentials from −80 to + 80 mV in 10 mV steps. As shown in Fig. 1A, at test potentials positive to –40 mV, Kv1.3 channel currents rapidly activated and slowly inactivated. However, with 30 μM Lovastatin application, Kv1.3 current was much smaller and inactivated faster (Fig. 1B). After washout, the peak current recovered nearly completely, while the current at the end of the pulse only reversed partially (Fig. 1C). We got the similar results from peripheral blood CD4+ T cells (PBTCs, Fig. 1D–F) and CD3+ T cells (data not shown). Next, different concentrations of Lovastatin ranging from 1 to 100 μM were applied to block the Kv1.3 channel in Jurkat cells. The current traces in the absence and presence of 10, 30 μM Lovastatin was shown in Fig. 1G. Whereas, the quantitative analysis of concentration-dependent block effect by Lovastatin on the peak and the current at the end of the pulse was shown in Fig. 1H,I, respectively. Using the Hill equation for non-linear fitting, the IC50 of Lovastatin on the peak current was calculated to be 39.81 ± 5.11 μM, with the Hill coefficient 0.56 ± 0.04; and the IC50 on the current at the end of the pulse was 6.92 ± 0.95 μM, with the Hill coefficient 0.75 ± 0.06.


Lovastatin blocks Kv1.3 channel in human T cells: a new mechanism to explain its immunomodulatory properties.

Zhao N, Dong Q, Qian C, Li S, Wu QF, Ding D, Li J, Wang BB, Guo KF, Xie JJ, Cheng X, Liao YH, Du YM - Sci Rep (2015)

Lovastatin blocked Kv1.3 channel currents in human T cells.(A–C) The representative Kv1.3 current traces recorded in Jurkat cells in the absence (A), presence (B) and washout (C) of 30 μM Lovastatin, which were elicited by 300 ms pulses at the test potentials from −80 to + 60 mV in 10 mV steps. (D–F) Representative Kv1.3 traces recorded in PBTCs in the absence (D), presence (E) and washout (F) of 30 μM Lovastatin. (G) Superimposed original Kv1.3 current traces at control, with 10, 30 μM Lovastatin applications, and washout in Jurkat cells. Kv1.3 currents were elicited by the depolarizing step pulses at + 40 mV with the holding potential at −80 mV every 10 s. (H) The dose-response curve of the peak Kv1.3 currents fitted with the Hill equation in Jurkat cells. The summarized data (6 cells) for each concentration are expressed as mean ± SEM. The IC50 and Hill coefficient were 39.81 ± 5.11 μM and 0.56 ± 0.04. (I) The dose-response curve of Kv1.3 currents at the end of the pulse from 6 Jurkat cells were fitted with the Hill equation. The IC50 and Hill coefficient were 6.92 ± 0.95 μM and 0.75 ± 0.06, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4663632&req=5

f1: Lovastatin blocked Kv1.3 channel currents in human T cells.(A–C) The representative Kv1.3 current traces recorded in Jurkat cells in the absence (A), presence (B) and washout (C) of 30 μM Lovastatin, which were elicited by 300 ms pulses at the test potentials from −80 to + 60 mV in 10 mV steps. (D–F) Representative Kv1.3 traces recorded in PBTCs in the absence (D), presence (E) and washout (F) of 30 μM Lovastatin. (G) Superimposed original Kv1.3 current traces at control, with 10, 30 μM Lovastatin applications, and washout in Jurkat cells. Kv1.3 currents were elicited by the depolarizing step pulses at + 40 mV with the holding potential at −80 mV every 10 s. (H) The dose-response curve of the peak Kv1.3 currents fitted with the Hill equation in Jurkat cells. The summarized data (6 cells) for each concentration are expressed as mean ± SEM. The IC50 and Hill coefficient were 39.81 ± 5.11 μM and 0.56 ± 0.04. (I) The dose-response curve of Kv1.3 currents at the end of the pulse from 6 Jurkat cells were fitted with the Hill equation. The IC50 and Hill coefficient were 6.92 ± 0.95 μM and 0.75 ± 0.06, respectively.
Mentions: Jurkat cells were held at −80 mV, and received the test potentials from −80 to + 80 mV in 10 mV steps. As shown in Fig. 1A, at test potentials positive to –40 mV, Kv1.3 channel currents rapidly activated and slowly inactivated. However, with 30 μM Lovastatin application, Kv1.3 current was much smaller and inactivated faster (Fig. 1B). After washout, the peak current recovered nearly completely, while the current at the end of the pulse only reversed partially (Fig. 1C). We got the similar results from peripheral blood CD4+ T cells (PBTCs, Fig. 1D–F) and CD3+ T cells (data not shown). Next, different concentrations of Lovastatin ranging from 1 to 100 μM were applied to block the Kv1.3 channel in Jurkat cells. The current traces in the absence and presence of 10, 30 μM Lovastatin was shown in Fig. 1G. Whereas, the quantitative analysis of concentration-dependent block effect by Lovastatin on the peak and the current at the end of the pulse was shown in Fig. 1H,I, respectively. Using the Hill equation for non-linear fitting, the IC50 of Lovastatin on the peak current was calculated to be 39.81 ± 5.11 μM, with the Hill coefficient 0.56 ± 0.04; and the IC50 on the current at the end of the pulse was 6.92 ± 0.95 μM, with the Hill coefficient 0.75 ± 0.06.

Bottom Line: However, 30 μM Lovastatin had no apparent effect on KCa current in human T cells.At last, Mevalonate application only partially reversed the inhibition of Lovastatin on IL-2 secretion, and the siRNA against Kv1.3 also partially reduced this inhibitory effect of Lovastatin.In conclusion, Lovastatin can exert immunodulatory properties through the new mechanism of blocking Kv1.3 channel.

View Article: PubMed Central - PubMed

Affiliation: Research Center of Ion Channelopathy, Institute of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.

ABSTRACT
Lovastatin is a member of Statins, which are beneficial in a lot of immunologic cardiovascular diseases and T cell-mediated autoimmune diseases. Kv1.3 channel plays important roles in the activation and proliferation of T cells, and have become attractive target for immune-related disorders. The present study was designed to examine the block effect of Lovastatin on Kv1.3 channel in human T cells, and to clarify its new immunomodulatory mechanism. We found that Lovastatin inhibited Kv1.3 currents in a concentration- and voltage-dependent manner, and the IC50 for peak, end of the pulse was 39.81 ± 5.11, 6.92 ± 0.95 μM, respectively. Lovastatin also accelerated the decay rate of current inactivation and negatively shifted the steady-state inactivation curves concentration-dependently, without affecting the activation curve. However, 30 μM Lovastatin had no apparent effect on KCa current in human T cells. Furthermore, Lovastatin inhibited Ca(2+) influx, T cell proliferation as well as IL-2 production. The activities of NFAT1 and NF-κB p65/50 were down-regulated by Lovastatin, too. At last, Mevalonate application only partially reversed the inhibition of Lovastatin on IL-2 secretion, and the siRNA against Kv1.3 also partially reduced this inhibitory effect of Lovastatin. In conclusion, Lovastatin can exert immunodulatory properties through the new mechanism of blocking Kv1.3 channel.

No MeSH data available.


Related in: MedlinePlus