Journal: Channels

Article Title: Association of the chemerin-CMKLR1 with atrial potassium current dysregulation and atrial fibrillation in obese mice

doi: 10.1080/19336950.2025.2611704

Figure Lengend Snippet: Localization and expression of potassium channel-associated proteins in mouse atrial myocytes. A. Immunofluorescence images showing membrane localization and expression of Kv4.3, Kv4.2, KChIP2, Kv1.5, and Kir2.1 in atrial cardiomyocytes from LFD and HFD groups. Scale bar, 100 μm. B. Representative Western blotting images and densitometric quantification of Kv4.3, Kv4.2, KChIP2, Kv1.5, and Kir2.1 protein expression in atrial cardiomyocytes from LFD and HFD mice. LFD, low-fat diet; HFD, high-fat diet. Data are presented as mean ± SD ( n = 3). ns, not significant; * p < 0.05, ** p < 0.01 vs. LFD group.

Article Snippet: Primary antibodies diluted in blocking buffer were applied overnight at 4°C as follows: resistin (1:1,000; Abcam, USA), chemerin (1:1,000; Abcam, USA), leptin (1:1,000; Abcam, USA), CMKLR1 (1:1,000; InvitrogenTM, USA), Kv4.3 (1:1,000; Alomone Labs, Israel), Kv4.2 (1:1,000; Alomone Labs, Israel), KChIP2 (1:1,000; Alomone Labs, Israel), Kv1.5 (1:1,000; Alomone Labs, Israel), Kir2.1 (1:1,000; Alomone Labs, Israel), β-Tubulin (1:1,000; Abcam, USA).

Techniques: Expressing, Immunofluorescence, Membrane, Western Blot

Journal: The Journal of Biological Chemistry

Article Title: A polybasic motif in alternatively spliced KChIP2 isoforms prevents Ca 2+ regulation of Kv4 channels

doi: 10.1074/jbc.RA118.006549

Figure Lengend Snippet: Ca2+ regulation of Kv4.2–KChIP2 complexes is KChIP isoform-dependent. a, consensus protein domain organization of KChIP family members (top). Protein domain organization of four KChIP2 isoforms that demonstrates N-terminal variability (below). b, two-way ANOVA returned significant differences in peak Kv4.2 current density between KChIP2 isoforms (p = 0.0005), by treatment (p = 0.0227), and the interaction (p = 0.0150). However, Kv4.2 peak current density was unaffected by intracellular Ca2+ when expressed with long forms of KChIP2 (KChIP2a1, p = 0.9415; KChIP2a, p = 0.9997), whereas Kv4.2 peak current was significantly increased in the presence of Ca2+ for shorter forms of KChIP2 (KChIP2b, p = 0.0114; KChIP2c, p = 0.0203). c, sequence alignment of human N-terminal domains of KChIP2 isoforms. The putative polybasic domain conserved in Ca2+-insensitive KChIP isoforms is underlined, and basic residues are indicated with an asterisk. d, site-directed acidification of the putative polybasic motif in KChIP2a1 rescues Ca2+ enhancement of peak current density. Two-way ANOVA returned no differences between WT KChIP2a1 and mutant KChIP2a1 groups by construct expression (p = 0.1419) or treatment (p = 0.6426); however, the interaction was significant (p = 0.0124) likely due to differences in peak current density between WT and mutant KChIP2a1. Sidak's multiple comparison revealed that mutant KChIP2a1 responded to Ca2+ (p = 0.0107), whereas WT KChIP2a1 did not (p = 0.6970) as also shown in b. Error bars, mean ± S.E. *, p < 0.05; ***, p < 0.001 by two-way ANOVA and Sidak's multiple comparison test. Refer to Table 2 for numerical data and replicate information.

Article Snippet: Kv4 auxiliary subunit expression was carried out using human DPP6 (RC216919), human KChIP1a (RC224442), KChIP1b (RC208255), KChIP2a1 (RC213131), KChIP2b (RC203823), KChIP3a (RC203957), KChIP4bL (RC211488), KChIP4a (RC211613), and mouse KChIP2a (MC211934) (Origene).

Techniques: Sequencing, Mutagenesis, Construct, Expressing

Journal: Scientific reports

Article Title: The Kv4 potassium channel modulator NS5806 attenuates cardiac hypertrophy in vivo and in vitro.

doi: 10.1038/s41598-024-70962-x

Figure Lengend Snippet: Fig. 5. Effects of NS5806 on Ito channel-related gene and protein expression. (A–C) Quantification of the mRNA levels of Kv4.2 (A), KChIP2 (B) and DPP6 (C). GAPDH served as an internal control (n = 9 in each group). (D) Representative immunoblots. Original blots are presented in Supplementary Figure S6–7. (E–G) Summary data of Kv4.2 (E), KChIP2 (F) and DPP6 (G) protein levels. GAPDH served as an internal control (n = 5 in each group). *P < 0.05, ** P < 0.01 versus the Sham + Vehicle group. #P < 0.05, ##P < 0.01 versus TAC + Vehicle.

Article Snippet: Primary antibodies against Kv4.2 (1:500, 75–016, NeuroMab, USA), KChIP2 (1:500, DF14620, 4 Vol:. (1234567890) Scientific Reports | (2024) 14:19839 | https://doi.org/10.1038/s41598-024-70962-x Affinity, China), DPP6 (1:200, APC-146, Alomone, Israel) and GAPDH (1:10,000, 10494-1-AP, Proteintech, China) were incubated at 4 °C overnight.

Techniques: Expressing, Control, Western Blot

Journal: The Journal of Biological Chemistry

Article Title: A polybasic motif in alternatively spliced KChIP2 isoforms prevents Ca 2+ regulation of Kv4 channels

doi: 10.1074/jbc.RA118.006549

Figure Lengend Snippet: Ca2+ regulation of Kv4.2–KChIP2 complexes is KChIP isoform-dependent. a, consensus protein domain organization of KChIP family members (top). Protein domain organization of four KChIP2 isoforms that demonstrates N-terminal variability (below). b, two-way ANOVA returned significant differences in peak Kv4.2 current density between KChIP2 isoforms (p = 0.0005), by treatment (p = 0.0227), and the interaction (p = 0.0150). However, Kv4.2 peak current density was unaffected by intracellular Ca2+ when expressed with long forms of KChIP2 (KChIP2a1, p = 0.9415; KChIP2a, p = 0.9997), whereas Kv4.2 peak current was significantly increased in the presence of Ca2+ for shorter forms of KChIP2 (KChIP2b, p = 0.0114; KChIP2c, p = 0.0203). c, sequence alignment of human N-terminal domains of KChIP2 isoforms. The putative polybasic domain conserved in Ca2+-insensitive KChIP isoforms is underlined, and basic residues are indicated with an asterisk. d, site-directed acidification of the putative polybasic motif in KChIP2a1 rescues Ca2+ enhancement of peak current density. Two-way ANOVA returned no differences between WT KChIP2a1 and mutant KChIP2a1 groups by construct expression (p = 0.1419) or treatment (p = 0.6426); however, the interaction was significant (p = 0.0124) likely due to differences in peak current density between WT and mutant KChIP2a1. Sidak's multiple comparison revealed that mutant KChIP2a1 responded to Ca2+ (p = 0.0107), whereas WT KChIP2a1 did not (p = 0.6970) as also shown in b. Error bars, mean ± S.E. *, p < 0.05; ***, p < 0.001 by two-way ANOVA and Sidak's multiple comparison test. Refer to Table 2 for numerical data and replicate information.

Article Snippet: Kv4 auxiliary subunit expression was carried out using human DPP6 (RC216919), human KChIP1a (RC224442), KChIP1b (RC208255), KChIP2a1 (RC213131), KChIP2b (RC203823), KChIP3a (RC203957), KChIP4bL (RC211488), KChIP4a (RC211613), and mouse KChIP2a (MC211934) (Origene).

Techniques: Sequencing, Mutagenesis, Construct, Expressing

Journal: Acta pharmacologica Sinica

Article Title: Knockout of interleukin-17A diminishes ventricular arrhythmia susceptibility in diabetic mice via inhibiting NF-κB-mediated electrical remodeling.

doi: 10.1038/s41401-021-00659-8

Figure Lengend Snippet: Fig. 4 Effects of IL-17 knockout on the Ito and KChIP2 expression in the hearts of diabetic mice. a Representative traces of the Ito. b Current density-voltage (I–V) relationship of the Ito. n = 8–11 cells. c Current density-voltage (I–V) relationship of the Iss. n = 9–16 cells. d Mean membrane capacitance of the Ito and Iss n = 9–16 cells. e The protein and mRNA levels of Kv4.2. n = 7. f The protein and mRNA levels of Kv4.3. n = 7. g The protein and mRNA levels of KChIP2. n = 5. *P < 0.05 vs. WT mice; #P < 0.05 vs. WT+DM mice. WT wild-type, IL-17 KO IL-17 knockout, WT+DM wild-type+diabetes mellitus, IL-17 KO+DM IL-17 knockout+diabetes mellitus.

Article Snippet: The primary antibodies included rabbit anti-mouse Nav1.5 (Alomone Labs, Israel), Kv4.2 (Alomone Labs, Israel), Kv4.3 (Alomone Labs, Israel), KChIP2 (Boster, China), Cav1.2 (Alomone Labs, Israel), and NF-κB (CST, USA). β-Actin was used as an internal control.

Techniques: Knock-Out, Expressing, Membrane

Journal: Acta pharmacologica Sinica

Article Title: Knockout of interleukin-17A diminishes ventricular arrhythmia susceptibility in diabetic mice via inhibiting NF-κB-mediated electrical remodeling.

doi: 10.1038/s41401-021-00659-8

Figure Lengend Snippet: Fig. 8 Knockout of IL-17 protects against ventricular arrhythmias in STZ-induced diabetic mice. Knockout of IL-17 downregulates the expression of NF-κB, which suppresses the expression of KCNIP2, which encodes potassium voltage-gated channel interacting protein 2; CACNA1C, which encodes the pore-forming subunit of the voltage-gated L-type calcium channel Cav1.2; and SCN5A, which encodes the pore-forming subunit of the voltage-gated sodium channel Nav1.5. Decreased expression of KChIP2 and Nav1.5 prolonged the APD and slowed the conduction velocity, which increased susceptibility to ventricular arrhythmias. KCNIP2, potassium voltage-gated channel interacting protein 2; CACNA1C, calcium voltage-gated channel subunit alpha 1 C; KCND2, potassium voltage-gated channel subfamily D member 2; KCND3, potassium voltage-gated channel subfamily D member 3; SCN5A, sodium voltage-gated channel alpha subunit 5; WT+DM, wild-type+diabetes mellitus; IL-17 KO+DM, IL-17 knockout+diabetes mellitus.

Article Snippet: The primary antibodies included rabbit anti-mouse Nav1.5 (Alomone Labs, Israel), Kv4.2 (Alomone Labs, Israel), Kv4.3 (Alomone Labs, Israel), KChIP2 (Boster, China), Cav1.2 (Alomone Labs, Israel), and NF-κB (CST, USA). β-Actin was used as an internal control.

Techniques: Knock-Out, Expressing

Journal: European Journal of Pharmacology

Article Title: In vitro ion channel profile and ex vivo cardiac electrophysiology properties of the R (-) and S (+) enantiomers of hydroxychloroquine

doi: 10.1016/j.ejphar.2021.174670

Figure Lengend Snippet: Inhibitory potencies of R (-)HCQ and S (+)HCQ on six cardiac ion channels of the Comprehensive in vitro Pro-arrhythmia Assay (CiPA) panel.

Article Snippet: Briefly, CHO cells expressing hERG or K V 7.1/minK were obtained from B'Sys (Switzerland), and Ca V 1.2/β2/α2δ1, K ir 2.1 or K V 4.3/KChIP2.2 from Charles River (USA), respectively.

Techniques: In Vitro