NBCe1 Na+-HCO3- cotransporter ablation causes reduced apoptosis following cardiac ischemia-reperfusion injury in vivo

Table 1 Enriched Gene Ontology categories in NBCe1 cardiac conditional KO mice

GO category	P-value	Q-value	Enrichment	(N, B, n, b)
GO categories dealing with ion homeostasis
GO:0006873 Cellular ion homeostasis	1.13E-4	5.68E-1	2.45	(21545, 579, 334, 22)
GO:0051453 Regulation of intracellular pH	1.92E-4	5.80E-1	5.86	(21545, 77, 334, 7)
GO:0030003 Cellular cation homeostasis	2.12E-4	4.58E-1	2.4	(21545, 564, 334, 21)
GO categories dealing with apoptosis
GO:0043652 Engulfment of apoptotic cell	4.09E-4	4.42E-1	19.35	(21545, 10, 334, 3)
GO:1901030 Mitochondrial membrane permeabilization involved in apoptotic signaling	4.09E-4	4.12E-1	19.35	(21545, 10, 334, 3)
GO categories dealing with membrane compartments
GO:0005783 Endoplasmic reticulum	2.82E-6	1.06E-3	2.03	(21545, 1493, 334, 47)
GO:0030315 T-tubule	3.45E-5	7.18E-3	7.65	(21545, 59, 334, 7)
GO:0016529 Sarcoplasmic reticulum	3.00E-4	3.30E-2	6.56	(21545, 59, 334, 6)
GO:0042383 Sarcolemma	4.84E-4	4.77E-2	4.41	(21545, 117, 334, 8)

GO categories were identified using the Two unranked list option of the GOrilla Gene Ontology program[24]. N is the total number of genes, B is the total number of genes associated with a specific GO term, n is the number of genes in the target set, b is the number of genes in the intersection. Enrichment = (b/n)/(B/N). Differential mRNA expression data were generated by RNA Seq analysis of hearts from 6 adult male mice for the NBCe1 KO (Slc4a4^flx/flx(Cre)) and NBCe1 WT (Slc4a4^flx/flx) genotypes.

Table 2 Ion channel and transporter genes altered in NBCe1-null hearts

Gene symbol	Description	Fold change	P value
Kcnj2	Inwardly-rectifying K+ channel J2	1.18	0.02
Kcnj11	Inwardly-rectifying K+ channel J11	1.14	0.03
Kcnk2	K+ channel K2; TREK-1	1.65	0
Kcna4	K+ channel, shaker-related 4; Kv1.4	1.50	0.05
Cacna1s	L type Ca2+ channel, alpha 1S subunit	1.44	0
Cacnb1	Ca2+ channel, beta 1 subunit	0.51	0
Atp2a1	Skeletal muscle SR Ca2+ pump	1.82	0.04
Slc9a1	Sarcolemmal Na+/H+ Exchanger	1.18	0.05
Slc9a9	Organellar Na+/H+ Exchanger	1.44	0.03
Slc16a3	Monocarboxylic acid transporter,	1.92	0.04
Slc1a5	Neutral amino acid transporter	0.81	0.04
Slc7a1	Cationic amino acid transporter, y+ system	1.24	0
Slc15a2	Proton/peptide transporter	1.87	0.01
Slc15a1	Oligopeptide transporter	0.56	0.03
Slc40a1	Iron transporter; ferroportin	0.86	0.02
Slc39a13	Zinc transporter	1.23	0.03
Slc36a1	Proton/amino acid symporter	0.83	0.05

Differential mRNA expression is presented as fold-changes in NBCe1-null hearts (Slc4a4^flx/flx(Cre)) relative to WT (Slc4a4^flx/flx) hearts.

Table 3 Differential expression of apoptosis genes in NBCe1-null hearts

Gene symbol	Description	Fold change	P value
Xkr8	X Kell Blood Group Precursor Related 8	0.61	0.015
Rac3	RAS-Related C3 Botulinum Substrate 3	0.36	0.016
Thbs1	Thrombospondin 1	0.79	0.020
Zfp13	Zinc Finger Protein 13	0.46	0.023
Sh3glb1	SH3-Domain GRB2-like B1 (Endophilin)	1.13	0.024
Siva1	SIVA1, Apoptosis-Inducing Factor	0.66	0.030
Msrb3	Methionine Sulfoxide Reductase B3	1.19	0.002
Xlrl	Xlr-like	1.77	0.003
Ier5	Immediate Early Response 5	0.80	0.005
Hint1	Histidine Triad Nucleotide Binding Protein 1	0.84	0.010
Stmn1	Stathmin 1	1.37	0.010

Differential mRNA expression is presented as fold-changes in NBCe1-null hearts (Slc4a4^flx/flx(Cre)) relative to WT (Slc4a4^flx/flx) hearts. The first six genes on this list were identified based on inclusion in the two apoptosis GO categories identified in Table 1.