RNA-Seq Analyses Reveal Roles of the HVCN1 Proton Channel in Cardiac pH Homeostasis

Figures

• 

  FIGURE 1. RNA sequencing analysis revealed a differential transcriptome profile in HVCN1−/− mouse heart. (A) Heatmap and hierarchical clustering of DEGs in the wild-type and HVCN1−/− hearts, n = 4 hearts for each group. (B) Principal component analysis of wild-type and HVCN1−/− hearts. (C) The volcano plot has red points representing upregulated DEGs, blue representing downregulated DEGs, and gray points representing non-DEGs. (D-E) Gene Ontology enrichment analysis of top significant gene groups either downregulated (D) or upregulated (E).

• 

  FIGURE 2. Downregulation of the NOX family of ROS-generating NADPH oxidases in HVCN1−/− hearts. Comparing relative gene expression levels of NOX1, NOX2, and NOX4 between WT (black) and HVCN1−/− (red) detected by RNA-seq (A-C) and qPCR (D-F). n = 4 independent experiments for RNA-seq; n = 3 independent experiments for qPCR; *p < 0.05.

• 

  FIGURE 3. Differentially expressed genes related to Cl−/HCO3- exchangers in HVCN1−/− hearts. Comparing relative gene expression levels of SLC4A1 (AE1), SLC4A2 (AE2), SLC4A3 (AE3), SLC26A6 between WT (black) and HVCN1−/− (red) detected by RNA-seq (A-D) and qPCR (E-H). n = 4 independent experiments for RNA-seq; n = 3 independent experiments for qPCR; *p < 0.05.

• 

  FIGURE 4. Differentially expressed genes related to other proton transporters/channels in HVCN1−/− hearts. Comparing relative gene expression levels of proton transporters between WT (black) and HVCN1−/− (red) including sodium-hydrogen exchanger 1 (NHE1) (A), a1-subunit of the V0 domain of V-type proton ATPase (ATP6V0A1) (B), and otopetrin proton channel 1 (OTOP1) (C), n = 4 independent experiments for RNA-seq; *p < 0.05.

• 

  FIGURE 5. Differentially expressed genes related to proton-coupled channels/transporters/antiporters in HVCN1−/− hearts. Comparing relative gene expression levels of proton-coupled transporters between WT (black) and HVCN1−/− (red) including acid-sensing ion channels ASIC1, ASIC2, ASIC3, ASIC4 (A-D), proton activated chloride channel TMEM206 (E), proton-coupled metal-ion transporters SLC11A1, SLC11A2 (F-G), proton-coupled amino acid transporters SLC36A1, SLC36A2, SLC36A4 (H-J), proton/amine antiporters SLC18A1, SLC18A2 (K-L), and proton-dependent oligopeptide transporters SLC15A2, SLC15A3, SLC15A4 (M-O). n = 4 independent experiments for RNA-seq; *p < 0.05.

• 

  FIGURE 6. Differentially expressed genes related to cardiac ion channels in HVCN1−/− hearts. Comparing relative gene expression levels of cardiac ion channels between WT (black) and HVCN1−/− (red) including cardiac sodium channel SCN5A (A), sodium channel beta subunits SCN1B and SCN2B (B-C), cardiac L-type calcium channel CACNA1C (D), T-type calcium channel CACNA1G (E), cardiac potassium channels KCNQ1 (F), KCNH2 (G), potassium channel beta subunits KCNE1 , KCNE3 , KCNE4 (H-J), Ito channels KNCD2, KCND3, KCNA4 (K-M), IK1 channels KCNJ2, KCNJ12 (N-O), Ikur channel KCNA5 (P), If channels HCN2, HCN4 (Q-R), and cardiac ryanodine receptor RYR2 (S) and SERCA pump ATPA2 (T). n = 4 independent experiments for RNA-seq; *p < 0.05.

• 

  FIGURE 7. Proposed roles of HVCN1 in regulating pH homeostasis in the heart. Proton (H+) extrusion by the HVCN1 channel compensates for the electrogenic activity of NOX and regulates the efficient generation of H2O2. In addition, HVCN1-mediated H+ current is associated with transport-mediated CO2 disposal. Except for HVCN1 functional regulation of pH homeostasis, the present study revealed that HVCN1 regulated the genetic expression of NOXs and SLC26A6 in the heart.