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Investigating the Mechanism of Hyperglycemia-Induced Fetal Cardiac Hypertrophy.

Han SS, Wang G, Jin Y, Ma ZL, Jia WJ, Wu X, Wang XY, He MY, Cheng X, Li WJ, Yang X, Liu GS - PLoS ONE (2015)

Bottom Line: Next, we found that the individual cardiomyocyte size increased in pre-gestational diabetes mellitus mice and in response to high glucose exposure.Meanwhile, the expression of β-MHC and BMP-10 was up-regulated.In cultured H9c2 cells exposed to high glucose, Nkx2.5 expression decreased, as detected by both immunostaining and western blotting, and the expression of KCNE1 and Cx43 was also restricted.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics and Neonatology, Institute of Fetal-Preterm Labor Medicine, The First Affiliated Hospital, Jinan University, Guangzhou, 510630, China.

ABSTRACT
Hyperglycemia in diabetic mothers enhances the risk of fetal cardiac hypertrophy during gestation. However, the mechanism of high-glucose-induced cardiac hypertrophy is not largely understood. In this study, we first demonstrated that the incidence rate of cardiac hypertrophy dramatically increased in fetuses of diabetic mothers using color ultrasound examination. In addition, human fetal cardiac hypertrophy was successfully mimicked in a streptozotocin (STZ)-induced diabetes mouse model, in which mouse cardiac hypertrophy was diagnosed using type-M ultrasound and a histological assay. PH3 immunofluorescent staining of mouse fetal hearts and in vitro-cultured H9c2 cells indicated that cell proliferation decreased in E18.5, E15.5 and E13.5 mice, and cell apoptosis in H9c2 cells increased in the presence of high glucose in a dose-dependent manner. Next, we found that the individual cardiomyocyte size increased in pre-gestational diabetes mellitus mice and in response to high glucose exposure. Meanwhile, the expression of β-MHC and BMP-10 was up-regulated. Nkx2.5 immunofluorescent staining showed that the expression of Nkx2.5, a crucial cardiac transcription factor, was suppressed in the ventricular septum, left ventricular wall and right ventricular wall of E18.5, E15.5 and E13.5 mouse hearts. However, cardiac hypertrophy did not morphologically occur in E13.5 mouse hearts. In cultured H9c2 cells exposed to high glucose, Nkx2.5 expression decreased, as detected by both immunostaining and western blotting, and the expression of KCNE1 and Cx43 was also restricted. Taken together, alterations in cell size rather than cell proliferation or apoptosis are responsible for hyperglycemia-induced fetal cardiac hypertrophy. The aberrant expression of Nkx2.5 and its regulatory target genes in the presence of high glucose could be a principal component of pathogenesis in the development of fetal cardiac hypertrophy.

No MeSH data available.


Related in: MedlinePlus

Nkx2.5 expression was suppressed in E18.5 and E15.5 PGDM mice.Nkx2.5 immunofluorescent staining (red) was performed on the vertical sections of the prenatal mouse hearts. All of the sections were counterstained with DAPI (blue). A-D: The representative images of H&E-stained vertical sections from the E18.5 control (A), E18.5 PGDM (B), E15.5 control (C) and E15.5 PDGM (D) mice. A1-A3/B1-B3: The vertical sections of the E18.5 mouse hearts from control cardiac VS (A1), RVW (A2), and LVW (A3) and PGDM cardiac VS (B1), RVW (B2), and LVW (B3). C1-C3/D1-D3: The vertical sections of E15.5 mouse hearts from control cardiac VS (C1), RVW (C2), and LVW (C3) and PGDM cardiac VS (D1), RVW (D2), and LVW (D3). E: Bar charts showing the percentage of Nkx2.5+ cells/DAPI cells in the VS, RVW and LVW of the E18.5 control and PGDM mice. F: Bar charts showing the percentage of Nkx2.5+ cells/DAPI cells in the VS, RVW and LVW of the E15.5 control and PGDM mice. G: Western blotting data showing Nkx2.5 expression at the protein level in E18.5 or E15.5 control and PGDM mice. *P<0.05, ***P<0.001 vs control. Scale bars: 400 μm in A-D and 100 μm in A1-D3.
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pone.0139141.g007: Nkx2.5 expression was suppressed in E18.5 and E15.5 PGDM mice.Nkx2.5 immunofluorescent staining (red) was performed on the vertical sections of the prenatal mouse hearts. All of the sections were counterstained with DAPI (blue). A-D: The representative images of H&E-stained vertical sections from the E18.5 control (A), E18.5 PGDM (B), E15.5 control (C) and E15.5 PDGM (D) mice. A1-A3/B1-B3: The vertical sections of the E18.5 mouse hearts from control cardiac VS (A1), RVW (A2), and LVW (A3) and PGDM cardiac VS (B1), RVW (B2), and LVW (B3). C1-C3/D1-D3: The vertical sections of E15.5 mouse hearts from control cardiac VS (C1), RVW (C2), and LVW (C3) and PGDM cardiac VS (D1), RVW (D2), and LVW (D3). E: Bar charts showing the percentage of Nkx2.5+ cells/DAPI cells in the VS, RVW and LVW of the E18.5 control and PGDM mice. F: Bar charts showing the percentage of Nkx2.5+ cells/DAPI cells in the VS, RVW and LVW of the E15.5 control and PGDM mice. G: Western blotting data showing Nkx2.5 expression at the protein level in E18.5 or E15.5 control and PGDM mice. *P<0.05, ***P<0.001 vs control. Scale bars: 400 μm in A-D and 100 μm in A1-D3.

Mentions: Nkx2.5 is indispensable for the differentiation of cardiac cardiomyocytes due to its role in regulating the expression of several essential transcription factors during heart formation [20, 21]. Therefore, we determined the expression of Nkx2.5 in the VS, RVW and LVW from the E18.5 and E15.5 control or PGDM mouse hearts. From Nkx2.5 immunofluorescent staining, we found that the numbers of Nkx2.5+ cells in the PGDM group were much lower than those in the control group (details following), in either the E18.5 or E15.5 mouse hearts (Fig 7A1–7D3). In the E18.5 mouse hearts, the number of Nkx2.5+ cells in the VS of the PGDM group (17.15±4.03%, n = 5) was significantly lower than that in the control group (74.56±5.74%, n = 5; P<0.001); the number of Nkx2.5+ cells in RVW of the PGDM group (27.21±4.72%, n = 5) was significantly lower than that in the control group (62.27±7.86%, n = 5; P<0.001); and the number of Nkx2.5+ cells in LVW of the PGDM group (43.32±2.59%, n = 5) was significantly lower than that in the control group (60.93±9.52%, n = 5; P<0.05) (Fig 7E). The numbers of Nkx2.5+ cells in the VS, RVW and LVW of the E15.5 PGDM mouse hearts (6.50±4.60%, 16.42±6.67% and 4.26±3.53%, respectively; n = 5) were also significantly lower than those in the control group (75.22±2.88%, 68.42±4.62% and 75.25±4.30%, respectively; n = 5; P<0.001) (Fig 7F). The western blotting data also showed reduced Nkx2.5 expression at the protein level in the E18.5 and E15.5 PGDM mouse hearts compared with that of the controls (Fig 7G).


Investigating the Mechanism of Hyperglycemia-Induced Fetal Cardiac Hypertrophy.

Han SS, Wang G, Jin Y, Ma ZL, Jia WJ, Wu X, Wang XY, He MY, Cheng X, Li WJ, Yang X, Liu GS - PLoS ONE (2015)

Nkx2.5 expression was suppressed in E18.5 and E15.5 PGDM mice.Nkx2.5 immunofluorescent staining (red) was performed on the vertical sections of the prenatal mouse hearts. All of the sections were counterstained with DAPI (blue). A-D: The representative images of H&E-stained vertical sections from the E18.5 control (A), E18.5 PGDM (B), E15.5 control (C) and E15.5 PDGM (D) mice. A1-A3/B1-B3: The vertical sections of the E18.5 mouse hearts from control cardiac VS (A1), RVW (A2), and LVW (A3) and PGDM cardiac VS (B1), RVW (B2), and LVW (B3). C1-C3/D1-D3: The vertical sections of E15.5 mouse hearts from control cardiac VS (C1), RVW (C2), and LVW (C3) and PGDM cardiac VS (D1), RVW (D2), and LVW (D3). E: Bar charts showing the percentage of Nkx2.5+ cells/DAPI cells in the VS, RVW and LVW of the E18.5 control and PGDM mice. F: Bar charts showing the percentage of Nkx2.5+ cells/DAPI cells in the VS, RVW and LVW of the E15.5 control and PGDM mice. G: Western blotting data showing Nkx2.5 expression at the protein level in E18.5 or E15.5 control and PGDM mice. *P<0.05, ***P<0.001 vs control. Scale bars: 400 μm in A-D and 100 μm in A1-D3.
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pone.0139141.g007: Nkx2.5 expression was suppressed in E18.5 and E15.5 PGDM mice.Nkx2.5 immunofluorescent staining (red) was performed on the vertical sections of the prenatal mouse hearts. All of the sections were counterstained with DAPI (blue). A-D: The representative images of H&E-stained vertical sections from the E18.5 control (A), E18.5 PGDM (B), E15.5 control (C) and E15.5 PDGM (D) mice. A1-A3/B1-B3: The vertical sections of the E18.5 mouse hearts from control cardiac VS (A1), RVW (A2), and LVW (A3) and PGDM cardiac VS (B1), RVW (B2), and LVW (B3). C1-C3/D1-D3: The vertical sections of E15.5 mouse hearts from control cardiac VS (C1), RVW (C2), and LVW (C3) and PGDM cardiac VS (D1), RVW (D2), and LVW (D3). E: Bar charts showing the percentage of Nkx2.5+ cells/DAPI cells in the VS, RVW and LVW of the E18.5 control and PGDM mice. F: Bar charts showing the percentage of Nkx2.5+ cells/DAPI cells in the VS, RVW and LVW of the E15.5 control and PGDM mice. G: Western blotting data showing Nkx2.5 expression at the protein level in E18.5 or E15.5 control and PGDM mice. *P<0.05, ***P<0.001 vs control. Scale bars: 400 μm in A-D and 100 μm in A1-D3.
Mentions: Nkx2.5 is indispensable for the differentiation of cardiac cardiomyocytes due to its role in regulating the expression of several essential transcription factors during heart formation [20, 21]. Therefore, we determined the expression of Nkx2.5 in the VS, RVW and LVW from the E18.5 and E15.5 control or PGDM mouse hearts. From Nkx2.5 immunofluorescent staining, we found that the numbers of Nkx2.5+ cells in the PGDM group were much lower than those in the control group (details following), in either the E18.5 or E15.5 mouse hearts (Fig 7A1–7D3). In the E18.5 mouse hearts, the number of Nkx2.5+ cells in the VS of the PGDM group (17.15±4.03%, n = 5) was significantly lower than that in the control group (74.56±5.74%, n = 5; P<0.001); the number of Nkx2.5+ cells in RVW of the PGDM group (27.21±4.72%, n = 5) was significantly lower than that in the control group (62.27±7.86%, n = 5; P<0.001); and the number of Nkx2.5+ cells in LVW of the PGDM group (43.32±2.59%, n = 5) was significantly lower than that in the control group (60.93±9.52%, n = 5; P<0.05) (Fig 7E). The numbers of Nkx2.5+ cells in the VS, RVW and LVW of the E15.5 PGDM mouse hearts (6.50±4.60%, 16.42±6.67% and 4.26±3.53%, respectively; n = 5) were also significantly lower than those in the control group (75.22±2.88%, 68.42±4.62% and 75.25±4.30%, respectively; n = 5; P<0.001) (Fig 7F). The western blotting data also showed reduced Nkx2.5 expression at the protein level in the E18.5 and E15.5 PGDM mouse hearts compared with that of the controls (Fig 7G).

Bottom Line: Next, we found that the individual cardiomyocyte size increased in pre-gestational diabetes mellitus mice and in response to high glucose exposure.Meanwhile, the expression of β-MHC and BMP-10 was up-regulated.In cultured H9c2 cells exposed to high glucose, Nkx2.5 expression decreased, as detected by both immunostaining and western blotting, and the expression of KCNE1 and Cx43 was also restricted.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics and Neonatology, Institute of Fetal-Preterm Labor Medicine, The First Affiliated Hospital, Jinan University, Guangzhou, 510630, China.

ABSTRACT
Hyperglycemia in diabetic mothers enhances the risk of fetal cardiac hypertrophy during gestation. However, the mechanism of high-glucose-induced cardiac hypertrophy is not largely understood. In this study, we first demonstrated that the incidence rate of cardiac hypertrophy dramatically increased in fetuses of diabetic mothers using color ultrasound examination. In addition, human fetal cardiac hypertrophy was successfully mimicked in a streptozotocin (STZ)-induced diabetes mouse model, in which mouse cardiac hypertrophy was diagnosed using type-M ultrasound and a histological assay. PH3 immunofluorescent staining of mouse fetal hearts and in vitro-cultured H9c2 cells indicated that cell proliferation decreased in E18.5, E15.5 and E13.5 mice, and cell apoptosis in H9c2 cells increased in the presence of high glucose in a dose-dependent manner. Next, we found that the individual cardiomyocyte size increased in pre-gestational diabetes mellitus mice and in response to high glucose exposure. Meanwhile, the expression of β-MHC and BMP-10 was up-regulated. Nkx2.5 immunofluorescent staining showed that the expression of Nkx2.5, a crucial cardiac transcription factor, was suppressed in the ventricular septum, left ventricular wall and right ventricular wall of E18.5, E15.5 and E13.5 mouse hearts. However, cardiac hypertrophy did not morphologically occur in E13.5 mouse hearts. In cultured H9c2 cells exposed to high glucose, Nkx2.5 expression decreased, as detected by both immunostaining and western blotting, and the expression of KCNE1 and Cx43 was also restricted. Taken together, alterations in cell size rather than cell proliferation or apoptosis are responsible for hyperglycemia-induced fetal cardiac hypertrophy. The aberrant expression of Nkx2.5 and its regulatory target genes in the presence of high glucose could be a principal component of pathogenesis in the development of fetal cardiac hypertrophy.

No MeSH data available.


Related in: MedlinePlus