Decrease in membrane phospholipids unsaturation correlates with myocardial diastolic dysfunction

Fig 1. SFA-rich HFD caused cardiac hypertrophy, fibrosis, and diastolic dysfunction. (A) Schema of HFD feeding protocol. Mice were fed either a high lard diet (HLD, rich in SFA), a high olive-oil diet (HOD, rich in MUFA), or a control diet (CD) from 4 weeks to 20 weeks of age. (B) Top, representative low-magnification views of hematoxylin and eosin staining of the heart sections. Scale bars: 1 mm. Bottom, heart weight (HW) normalized by tibial length (TL). (n = 6). (C) Quantification of cardiomyocyte surface area. (n = 3). (D) Top, representative image of azan staining of the heart sections. Scale bars: 100 μm. Bottom, quantification of the fibrotic area. (n = 3). (E) Quantification of TUNEL-positive cardiomyocytes. (n = 3). (F) Relative expression of hypertrophy-associated and fibrosis-associated genes. (n = 6). (G) Relative expression of TRPC channels. (n = 6). (H) Left, representative pressure–volume curve. Right, LV end-diastolic pressure (LVEDP). (n = 10). (I) End-diastolic pressure–volume relationship (EDPVR). (n = 10). Data were presented as mean ± SEM. * P < 0.05, ** P < 0.01, by ANOVA followed by post hoc Tukey–Kramer tests. See also Tables 1 and 2.

Fig 2. SFA-rich HFD increased fatty acid saturation in cardiac membrane phospholipids. (A) Relative microRNA (miR) expression. (n = 6). (B) Top, Representative immunoblots of phospho-AMPK(Thr172)(P-AMPK), AMPK and GAPDH. Bottom, Quantification of P-AMPK to AMPK ratio by densitometry analysis. (n = 3). (C) Top, representative immunoblots of Sirt1 and GAPDH. Bottom, quantification of Sirt1 by densitometry analysis. (n = 4). (D) Relative Sirt1 deacetylase activity. (n = 6). (E) Relative gene expression of mitochondrial biogenesis, TG turnover, PPARα-target genes in hearts. (n = 6). (F) Triglyceride (TG) content in hearts. (n = 4). (G) Ceramide content in hearts. (n = 4). (H) Diacylglycerol (DAG) content in hearts. (n = 4). (I) FA composition (mol% of phospholipids) of saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) and the SFA/MUFA ratio. (n = 4). (J) Relative expression of UPR signaling genes. (n = 5). sXBP1 indicates spliced-XBP1. (K) Top, representative immunoblots of SCD1 and GAPDH. Bottom, quantification of SCD1 by densitometry analysis. (n = 4). Data were presented as mean ± SEM. * P < 0.05, ** P < 0.01, by ANOVA followed by post hoc Tukey–Kramer tests. See also Table 1.

Fig 3. Palmitate increased SFA/MUFA ratio in membrane phospholipid and induced UPR in neonatal rat cardiomyocytes. Neonatal rat cardiomyocytes were stimulated by fatty acids (200 μmol/L). (A) Fatty acid composition (mol% of phospholipids) of saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) and the SFA/MUFA ratio after fatty acid stimulation for 6 hours. (n = 4). (B) Relative expression of UPR signaling genes after palmitate stimulation for 6 hours. Concentrations of palmitate were 50, 100, 200 and 400 μmol/L. (n = 4). sXBP1 indicates spliced-XBP1. (C) Relative expression of PPARα-target genes after co-administration of palmitate and oleate for 6 hours. Concentrations of each fatty acid was 200 μmol/L. (n = 4). (D) Relative expression of UPR signaling genes after co-administration of palmitate and oleate for 6 hours. Concentrations of oleate were 50, 100 and 200 μmol/L. (n = 4). sXBP1 indicates spliced-XBP1. (E) Relative expression of TRPC channels after palmitate stimulation for 12 hours. Concentrations of palmitate were 50, 100, 200 and 400 μmol/L. (n = 4). (F) Relative expression of TRPC channels after co-administration of palmitate and oleate for 12 hours. Concentrations…