Fig 2: Differential mRNA and protein expression levels of ion channels in mCCDcl1 cells.A. qPCR analysis of mRNA expression levels of marker channels relative to the AQP2 water channel. The mechanosensitive TRPV4 channel mRNA levels and ROMK mRNA levels are relatively high while a second mechanosensitive TRP channel, TRPV2, are very low. For comparison, mRNA expression levels for all channels are also given, relative to AQP2 mRNA levels, in the accompanying Table 1. B. qPCR mRNA expression levels of KCa channels relative to the ROMK channel. It shows that SK1, SK3, IK1 are expressed at relative high mRNA levels, BKa at moderate mRNA levels, and SK2 at low mRNA levels. C. mRNA expression of BK channel subunits relative to BKa mRNA levels. It shows high relative mRNA levels for BKß1 and BKß2, but relatively low levels for BKß4. D. Immunoblots of mCCDcl1 cells for the key channels showing appropriate protein bands for TRPV4 (98 kD), SK1 (64 kD), SK3 (81 kD), IK1 (45 kD), and BKa (110 kD).

Fig 3: Differential mRNA expression levels of ion channels in mouse kidney.A. qPCR anlysis of mRNA expression levels of marker channels relative to the AQP2 water channel. As in mCCDcl1 cells, the mechanosensitive TRPV4 channel mRNA levels and ROMK mRNA levels are relatively high while mRNA levels for a second mechanosensitve TRP channel, TRPV2, are very low. For comparison mRNA expression levels for all channels are also given, relative to AQP2 mRNA levels, in the accompanying Table 1. B. qPCR analysis of mRNA expression levels of KCa channels in mouse kidney relative to the ROMK channel. It shows that SK1, SK2, and SK3 are expressed at relative high mRNA levels while IK1 and BKa are expressed at moderate mRNA levels. C. mRNA expression of BK channel subunits relative to BKa mRNA levels. The results show high relative mRNA levels for BKß4, moderate mRNA levels for BKß2, and low mRNA levels for BKß4.

Fig 4: Hdac-related remodeling of Kcnn1 mRNA in HL-1 atrial myocytes. (a–h) Left panels, transcript abundance of indicated Hdacs was calculated following application of respective anti-Hdac siRNAs (n = 6 each) in relation to control cell cultures (Ctrl; n = 6 each). (a-h) Right panels, relative Kcnn1 (n = 6 each) mRNA levels were measured after genetic knockdown of indicated Hdacs and compared with respective controls in the absence of siRNA (n = 6 each). Please note that data on Hdac2 suppression by anti-Hdac2 siRNA have been published previously (Rahm et al., 2021). Data are given as box plots with dots representing individual data. *p < 0.05, **p < 0.01, ***p < 0.001 versus control cells

Fig 5: MIA-SI increases the expression levels of Nav1.2 and SK3 channels. (A) Representative immunoblots of Nav1.2, Nav1.6 and tubulin, run on a same gel. Each band represents samples from one animal. (B,C) Average Nav1.2 and Nav1.6 protein levels in PFC in two experimental groups. (D) Averaged ratio of Nav1.2 to the sum of Nav1.2 and Nav1.6 was increased by MIA-SI. (E) Representative immunoblots of SK1, SK2, SK3, and tubulin run on a same gel. (F–H) Average SK1, SK2, and SK3 protein levels in PFC of experimental animals. For each protein, blots were cropped to retain the important bands at the same size of the same membrane. *p < 0.05; **p < 0.01.