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Triarylmethanes, a new class of cx50 inhibitors.

Bodendiek SB, Rubinos C, Trelles MP, Coleman N, Jenkins DP, Wulff H, Srinivas M - Front Pharmacol (2012)

Bottom Line: We initially screened a library of common ion channel modulating pharmacophores for their inhibitory effects on Cx50 GJ channels, and identified four new classes of compounds.The SAR studies also indicated that the TRAM pharmacophore required for connexin inhibition is significantly different from the pharmacophore required for blocking the calcium-activated KCa3.1 channel.In addition, our results indicate that a similar approach may be used to find specific inhibitors of other connexin subtypes.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, University of California Davis, CA, USA.

ABSTRACT
The paucity of specific pharmacological agents has been a major impediment for delineating the roles of gap junction (GJ) channels formed by connexin proteins in physiology and pathophysiology. Here, we used the selective optimization of side activities (SOSA) approach, which has led to the design of high affinity inhibitors of other ion channels, to identify a specific inhibitor for channels formed by Cx50, a connexin subtype that is primarily expressed in the lens. We initially screened a library of common ion channel modulating pharmacophores for their inhibitory effects on Cx50 GJ channels, and identified four new classes of compounds. The triarlymethane (TRAM) clotrimazole was the most potent Cx50 inhibitor and we therefore used it as a template to explore the structure activity relationship (SAR) of the TRAMs for Cx50 inhibition. We describe the design of T122 (N-[(2-methoxyphenyl)diphenylmethyl]-1,3-thiazol-2-amine) and T136 (N-[(2-iodophenyl)diphenylmethyl]-1,3-thiazol-2-amine), which inhibit Cx50 with IC(50)s of 1.2 and 2.4 μM. Both compounds exhibit at least 10-fold selectivity over other connexins as well as major neuronal and cardiac voltage-gated K(+) and Na(+) channels. The SAR studies also indicated that the TRAM pharmacophore required for connexin inhibition is significantly different from the pharmacophore required for blocking the calcium-activated KCa3.1 channel. Both T122 and T136 selectively inhibited Cx50 GJ channels in lens epithelial cells, suggesting that they could be used to further explore the role of Cx50 in the lens. In addition, our results indicate that a similar approach may be used to find specific inhibitors of other connexin subtypes.

No MeSH data available.


Related in: MedlinePlus

(A) Dose-concentration curve for Cx50 inhibition by clotrimazole. (B) Connexin-selectivity profile of clotrimazole (10 μM). Shown is percentage of current inhibition (mean ± SEM).
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Figure 2: (A) Dose-concentration curve for Cx50 inhibition by clotrimazole. (B) Connexin-selectivity profile of clotrimazole (10 μM). Shown is percentage of current inhibition (mean ± SEM).

Mentions: Clotrimazole reversibly inhibited Cx50 expressed in N2A cells with an IC50 of 5 μM and a Hill slope of ∼ 2.1 (Figure 2). At concentrations of 10 μM clotrimazole had no effect on channels built out of Cx32, Cx36, and Cx46 (Figure 2). GJ channel conductance in all cases was measured by using the dual whole-cell patch-clamp technique as described in the Section “Materials and Methods” (Srinivas et al., 2001; Srinivas and Spray, 2003; Cruikshank et al., 2004).


Triarylmethanes, a new class of cx50 inhibitors.

Bodendiek SB, Rubinos C, Trelles MP, Coleman N, Jenkins DP, Wulff H, Srinivas M - Front Pharmacol (2012)

(A) Dose-concentration curve for Cx50 inhibition by clotrimazole. (B) Connexin-selectivity profile of clotrimazole (10 μM). Shown is percentage of current inhibition (mean ± SEM).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3368247&req=5

Figure 2: (A) Dose-concentration curve for Cx50 inhibition by clotrimazole. (B) Connexin-selectivity profile of clotrimazole (10 μM). Shown is percentage of current inhibition (mean ± SEM).
Mentions: Clotrimazole reversibly inhibited Cx50 expressed in N2A cells with an IC50 of 5 μM and a Hill slope of ∼ 2.1 (Figure 2). At concentrations of 10 μM clotrimazole had no effect on channels built out of Cx32, Cx36, and Cx46 (Figure 2). GJ channel conductance in all cases was measured by using the dual whole-cell patch-clamp technique as described in the Section “Materials and Methods” (Srinivas et al., 2001; Srinivas and Spray, 2003; Cruikshank et al., 2004).

Bottom Line: We initially screened a library of common ion channel modulating pharmacophores for their inhibitory effects on Cx50 GJ channels, and identified four new classes of compounds.The SAR studies also indicated that the TRAM pharmacophore required for connexin inhibition is significantly different from the pharmacophore required for blocking the calcium-activated KCa3.1 channel.In addition, our results indicate that a similar approach may be used to find specific inhibitors of other connexin subtypes.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, University of California Davis, CA, USA.

ABSTRACT
The paucity of specific pharmacological agents has been a major impediment for delineating the roles of gap junction (GJ) channels formed by connexin proteins in physiology and pathophysiology. Here, we used the selective optimization of side activities (SOSA) approach, which has led to the design of high affinity inhibitors of other ion channels, to identify a specific inhibitor for channels formed by Cx50, a connexin subtype that is primarily expressed in the lens. We initially screened a library of common ion channel modulating pharmacophores for their inhibitory effects on Cx50 GJ channels, and identified four new classes of compounds. The triarlymethane (TRAM) clotrimazole was the most potent Cx50 inhibitor and we therefore used it as a template to explore the structure activity relationship (SAR) of the TRAMs for Cx50 inhibition. We describe the design of T122 (N-[(2-methoxyphenyl)diphenylmethyl]-1,3-thiazol-2-amine) and T136 (N-[(2-iodophenyl)diphenylmethyl]-1,3-thiazol-2-amine), which inhibit Cx50 with IC(50)s of 1.2 and 2.4 μM. Both compounds exhibit at least 10-fold selectivity over other connexins as well as major neuronal and cardiac voltage-gated K(+) and Na(+) channels. The SAR studies also indicated that the TRAM pharmacophore required for connexin inhibition is significantly different from the pharmacophore required for blocking the calcium-activated KCa3.1 channel. Both T122 and T136 selectively inhibited Cx50 GJ channels in lens epithelial cells, suggesting that they could be used to further explore the role of Cx50 in the lens. In addition, our results indicate that a similar approach may be used to find specific inhibitors of other connexin subtypes.

No MeSH data available.


Related in: MedlinePlus