Fig 1.
UAS-apoLpp RNAi>W1118 group was exposed to HFD for 5 days, resulting in obesity and abnormal heart rhythm.
(A) Photographs and body weights of 10-day-old flies. The body weight was obtained by weighing flies on an electronic microbalance, N = 15. The flies in the HFD group were heavier compared to the NF group. (B) ORO staining of the abdomen of flies. Quantification of ORO intensity, N = 5. (B) ORO staining of fly abdomens. Quantification of ORO intensity, N = 5. The intensity of ORO staining in the abdomen of flies in the HFD group was higher, compared to the HF group. (C) Drosophila M-mode cardiogram, the red rectangle represents fibrillation, and the interception length is 10 s (This refers to the length of the electrocardiogram of 0–10 s). (D-F) M-Mode analysis. Quantification of the fly heart rate, arrhythmia index, and fibrillation, N = 30. The heart rate, arrhythmia index, and fibrillation of flies in the HFD group were higher than those in the NF group. (G) The relative expression level of apoLpp in cardiomyocytes of flies. The apoLpp in the cardiomyocytes of flies in the HFD group was significantly greater than in the NF group. The samples included at least 60 isolated hearts. (H) Whole-body TG levels in flies. The whole-body TG level of the HFD group was significantly higher than that of the NF group. N = 5, repeated three times. (I) Drosophila climbing index. The climbing index of the HFD group was significantly less than that of the NF group. The climbing index = number of flies at the top/total number of flies, N = 50, repeated three times. The detailed method is given in the (S2 Table).
Fig 2.
Under HFD feeding, inhibition of apoLpp in cardiomyocytes can reduce obesity and abnormal heart rhythm.
(A) Photographs and body weights of 10-day-old flies. The body weight was obtained with an electronic microbalance, N = 15. The flies in the HFD+KD group were lighter compared to the HFD group. (B) ORO staining of the fly abdomens. Quantification of ORO intensity, N = 5. The intensity of ORO staining in the fly abdomens in the HFD+KD group was reduced, compared with the HFD group. (C) Drosophila M-mode cardiogram, the red rectangle represents fibrillation, and the interception length was 10 s (This refers to the length of the electrocardiogram of 0–10 s). (D-F) M-Mode analysis. Quantification of fly heart rate, arrhythmia index, and fibrillation, N = 30. The heart rate, arrhythmia index, and fibrillation of flies in the HFD+KD group were lower than in the HFD group. (G) The relative expression level of apoLpp in the cardiomyocytes of flies. The apoLpp in cardiomyocytes of flies in the HFD+KD group was significantly lower than that in the HFD group. The test samples included at least 60 isolated hearts. (H) Whole-body TG levels in flies. The whole-body TG level of the HFD+KD group was significantly lower than that of the HFD group. N = 5, repeated three times.
Fig 3.
Regular exercise can reduce the expression level of apoLpp mRNA in cardiomyocytes and reverse the abnormal heart rhythm caused by the HFD diet.
(A) Photographs and body weights of 10-day-old flies. The body weight was obtained using an electronic microbalance, N = 15. The body weight of flies in the HE group was lower than the weight of the HFD group. (B) ORO staining of the abdomen of flies. Quantification of ORO intensity, N = 5. The intensity of ORO staining in the abdomen of flies in the HFD+E group was reduced compared to the HFD group. (C) Drosophila M-mode cardiogram, the red rectangle represents fibrillation, and the interception length is 10 s (This refers to the length of the electrocardiogram of 0–10 s). (D-F) M-Mode analysis. Quantification of the fly heart rate, arrhythmia index and fibrillation, N = 30 and 20. The heart rate, arrhythmia index, and fibrillation of flies in the HFD+E group were lower than those in the HFD group. (G) Whole-body TG levels in flies. The whole-body TG level of the HFD+E group was significantly lower than that of the HFD group. N = 5, repeated three times. (H) Relative expression level of apoLpp in cardiomyocytes of flies. The apoLpp in cardiomyocytes of flies in the HFD+E group was significantly lower than that in the HFD group. The samples included at least 60 isolated hearts.
Fig 4.
Combined effect of regular exercise and apoLpp knockdown in cardiomyocytes.
(A) Photographs and body weights of 10-day-old flies. The body weight was obtained using an electronic microbalance, N = 15. The body weight of flies in the HFD group was significantly higher than the other three groups. (B) ORO staining of the abdomen of flies. Quantification of ORO intensity, N = 5. The intensity of ORO staining of flies in the HFD group was significantly higher than that of the other three groups. (C) Drosophila M-mode cardiogram and the interception length was 10 s (This refers to the length of the electrocardiogram of 0–10 s). (D-F) M-Mode analysis. Quantification of fly heart rate, arrhythmia index and fibrillation, N = 30. The heart rate, arrhythmia index and fibrillation of the three groups of NF, HFD+KD and HFD+E+KD were significantly lower than those of the HFD group. Compared with the HFD+KD group, the HFD+E+KD group had no significant difference in heart rate and fibrillation, but the arrhythmia index was significantly lower. (G) The relative expression level of apoLpp in cardiomyocytes of flies. The expression level of apoLpp mRNA in cardiomyocytes of HFD group was significantly higher than that of the other three groups. In addition, compared with HFD+KD, the expression of apoLpp mRNA in cardiomyocytes of HFD+E+KD group was significantly reduced. The samples included at least 60 isolated hearts. (H) Whole-body TG levels in flies. The whole-body TG level in the HFD group was significantly higher than the other three groups. In addition, compared with the NF and HFD+KD groups, the HFD+E+KD group’s whole-body TG levels were significantly lower. N = 5, repeated three times.