Slick K+ channels contribute to cardiac remodeling, fibrosis, and dysfunction in postinfarction hearts
Jiaqi Yang, Lin Zhu, David Spähn, Melanie Cruz Santos, Sophia Schanz, Selina Maier, Lena Birkenfeld, Helmut Bischof, Anna Roslan, Nina Wettschureck, Oliver Borst, Lucas Matt, Robert Lukowski
Jiaqi Yang, Lin Zhu, David Spähn, Melanie Cruz Santos, Sophia Schanz, Selina Maier, Lena Birkenfeld, Helmut Bischof, Anna Roslan, Nina Wettschureck, Oliver Borst, Lucas Matt, Robert Lukowski
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Research Article Cardiology Cell biology

Slick K+ channels contribute to cardiac remodeling, fibrosis, and dysfunction in postinfarction hearts

Abstract

Resident cardiac fibroblast–derived (RCF-derived) cardiac myofibroblasts (CMFs) contribute to myocardial repair but also drive adverse ventricular remodeling and contractile dysfunction after myocardial infarction (MI). The sodium-activated potassium channel Slick (Slo2.1) has been described in cardiomyocyte (CM) mitochondria; however, transcriptomic analyses indicate higher Slick expression in RCFs/CMFs. Here, we investigated the role of Slick in cardiac fibroblast function and post-MI remodeling. Using live-cell imaging and whole-cell patch-clamp recordings, we found that plasma membrane Slick channels in RCFs and CMFs regulated potassium (K+) efflux and modulated store-operated calcium entry (SOCE), particularly in CMFs. Global Slick KO and conditional CMF-specific KO hearts exhibited reduced fibrosis and preserved left ventricular function after ischemia/reperfusion injury. This cardioprotection was associated with diminished CMF activation and proliferation, reduced inflammation, and improved CM survival after MI. Collectively, these findings identify fibroblast Slick channels as regulators of SOCE-dependent fibrogenesis and demonstrate that their deletion mitigates maladaptive remodeling and functional decline after MI.

Authors

Jiaqi Yang, Lin Zhu, David Spähn, Melanie Cruz Santos, Sophia Schanz, Selina Maier, Lena Birkenfeld, Helmut Bischof, Anna Roslan, Nina Wettschureck, Oliver Borst, Lucas Matt, Robert Lukowski

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Figure 5

Loss of Slick attenuates proliferation and fibrotic gene expression in CMFI/R.

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Loss of Slick attenuates proliferation and fibrotic gene expression in C...
(A) RT-qPCR analysis of Kcnt2 expression in cultured CMFs and in CMFI/R, normalized to Hprt. Mann-Whitney U test, *P < 0.05 (n = 6 hearts for CMF and n = 13 hearts for CMFI/R). (B) I-V relationships of persistent currents in WT and KO CMFI/R. Two-way ANOVA followed by Šidák’s multiple-comparison test, ***P < 0.001 (n = 6 hearts per genotype). (C) Representative outward current traces in WT and KO CMFI/R. (D and E) SOCE traces in WT and KO CMFI/R treated with DMSO (basal) or GSK7975A. (F) ΔSOCE (Rmax – Rmin during Ca2+ re-addition) in CMFI/R. GSK7975A significantly reduced SOCE in WT. Two-way ANOVA followed by Tukey’s multiple-comparison test, *P < 0.05 (n = 5 hearts for basal WT; n = 6 hearts for all other groups). (G) Representative brightfield images (0 h, 72 h) of grid-plate-based proliferation assay. Scale bar: 100 μm. (H) Quantitative analysis of proliferation rate over time. Two-way ANOVA with Šidák’s multiple-comparison test, ***P < 0.001 (n = 7 CTR and n = 11 mKO). (I) MTT assay of CMFI/R. Two-way ANOVA with Šidák’s multiple-comparison test, ***P < 0.001 (n = 6 hearts per genotype). (J and K) Western blot analysis of α-SMA in CMFI/R, normalized to GAPDH. Two-tailed unpaired Student’s t test, ***P < 0.001 (n = 5 hearts per group). (L–N) RT-qPCR analysis of profibrotic transcripts, normalized to Hprt. (L) Acta2 expression. Mann-Whitney U test (*P < 0.05; n = 7 CTR, n = 8 mKO). (M) Tgfb1 expression. Two-tailed unpaired Student’s t test, *P < 0.05 (n = 5 CTR, n = 8 mKO). (N) Col3a1 expression. Two-tailed unpaired Student’s t test (*P < 0.05; n = 7 CTR, n = 8 mKO).