Fig 2: NR supplementation, NAD+ salvage and mitochondrial function in H6PDKO muscle. a-d NAD+, NAD(H), total NAD(H) quantification and ratio of NAD+/NADH in TA of WT and H6PDKO +/− intraperitoneal (i.p.) Nicotinamide Riboside (NR) (n = 6-9). e qRT-PCR data of genes involved in the biosynthesis of NAD+ and salvage of NAM in WT and H6PDKO muscle +/− i.p. NR (n = 6-9). f qRT-PCR data of genes critical carnitine and fatty acids metabolism in WT and H6PDKO muscle +/− i.p. NR (n = 6-9). g-h Western blots and quantification of the NAM salvage protein NAMPT and the skeletal muscle specific protein NRK2 (n = 6). i High-resolution respirometry of fatty acid oxidation in permeabilised TA tissue from WT and H6PDKO i.p NR (n = 3). j High-resolution respiration for fatty acid oxidation using WT and H6PDKO after i.p NR permeabilised SOL (n = 3). k Western blots showing total lysine acetylation and IDH2 acetylation in WT and H6PDKO muscle +/− i.p NR. l Western blots showing ER stress regulator CHOP and protein folding factors PDI and ERO1a in WT and H6PDKO +/− i.p NR. (n = 6-9). *P < 0.05, **P < 0.01 and ***P < 0.001

Fig 3: Identification of ERO1A as a direct target gene by mass spectrometry analysis and ChIP-Seq. (A) Volcano plot showing differentially expressed proteins between the knockdown and control groups. The upregulated and downregulated proteins (P < 0.05 for both) are shown in red and blue, respectively. Gray represents no significant change in the expression level. (B) Differentially expressed proteins’ subcellular localization. (C) Functional categorization by Gene Ontology (GO) analysis of the differentially expressed proteins between knockdown and control cells. The GO terms among the three main categories of GO classification (biological process, cellular component and molecular function) are revealed. The x axis represents the number of proteins in a particular GO term within the main category. (D) ChIP analysis shows that PPARδ as a transcription factor binds to the intron sites of ERO1A (Gene ID number: 014584) which are highlighted with the red rectangle in the lower panel. The tracks below the lower panel are for the annotations of the chromosomal region of ERO1A. Exon is indicated in purple arrow while Intro in green arrow. The black arrow presents the Transcriptional orientation. Numbers below the black arrow denote chromosomal positions in ERO1A. The binding sites are located between chr14_53106632_53162649.

Fig 4: Molecular and phenotypic analysis of H6PD/NRK2 Double knockout mice. a-d NAD+, NADH, total NAD(H) and ratio of NAD+/NADH in WT, H6PDKO, NRK2KO and DKO (H6PDKO-NRK2KO) TA muscle (n = 3-6). e-g Skeletal muscle tissue weights from WT, H6PDKO, NRK2KO and H6-NRK2 Double Knockout (DKO) (n = 3-6). h qRT-PCR of NAD+ biosynthetic gene expression in WT, H6PDKO, NRK2 KO and DKO in TA (n = 3-6). i qRT-PCR of mitochondrial and acyl-CoA genes in TA of WT, H6PDKO, NRK2 KO and DKO (n = 3-6). j Western blots of total lysine acetylation, IDH2 and H3K56 acetylation in WT, H6PDKO, NRK2KO and DKO muscle protein lysates (n = 3-6). k Western blots of CHOP and protein folding factors PDI and ERO1a in WT, H6PDKO, NRK2 KO and DKO muscle lysates (n = 3-6). *P < 0.05, **P < 0.01 and ***P < 0.001

Fig 5: circ-ACACA/miR-582-5p/ERO1A promotes the glycolysis of cervical cancer cells. (A) ECAR after HeLa cells were transfected with shRNA-circ-ACACA and miR-582-5p inhibitor or pcDNA3.1-ERO1A. *P<0.05, **P<0.01, ***P<0.001 vs. shRNA-NC; #P<0.05, ##P<0.01, ###P<0.001 vs. shRNA circ-ACACA+NC inhibitor; ΔP<0.05 and ΔΔΔP<0.001 vs. shRNA circ-ACACA+pcDNA3.1-NC. (B) Lactate levels and (C) glucose content were assessed with commercially available kits. (D) Metabolite analysis and (E) glycolysis-related protein expression after HeLa cells were transfected with shRNA-circ-ACACA and miR-582-5p inhibitor or pcDNA3.1-ERO1A. *P<0.05, **P<0.01, ***P<0.001. circ-ACACA, circular RNA acetyl-CoA-carboxylase α; ECAR, extracellular acidification rate; ERO1A, endoplasmic reticulum disulphide oxidase 1α; GLUT1, glucose transporter type 1; HIF1A, hypoxia-inducible factor 1α; HK2, hexokinase-2; LDHA, lactate dehydrogenase A; miR, microRNA; NC, negative control; shRNA, short hairpin RNA; OM, oligomycin; 2-DG, 2-deoxy-D-glucose.