Fig 2: VB protected APP/PS1 mice against ER stress. VB reduced the concentrations of the following proteins related to ER stress in mice brains by ELISA: a MANF, b BiP, c ATF6, d p-IRE1/IRE1, e XBP1, f p-PERK/PERK, g p-eIF2a/eIF2a, h ATF4, i CHOP, and j caspase 12. The data are presented as mean ± SEM (n = 8/group). #p < 0.05, ##p < 0.01, and ###p < 0.001 vs. WT mice, *p < 0.05 and ***p < 0.001 vs. APP/PS1 mice

Fig 3: Effect of TS and APS on the transcript levels of ERS-UPR-related genes in transported-chicks. (A) GRP78, glucose regulated protein78kD. (B) ATF6, activating transcription factor 6. (C) PERK, protein kinase RNA-like ER kinase. (D) eIF2a, eukaryotic initiation factor 2. (E) ATF4, activating transcription factor 4. (F) IRE1, inositol-requiring enzyme 1a. (G) Heat map of relative mRNA levels of ERS-UPR-related genes. (H) PCA of ERS-UPR-related factor levels. Data are presented as the mean ± SD. *P < 0.05 and **P < 0.01. At the same time point, the same letters mean the difference is not significant (P > 0.05), different small letters mean a significant difference (P < 0.05) and different capital letters for the extremely significant difference (P < 0.01).

Fig 4: ATF4 silencing improves cardiac function and relieves interstitial fibrosis in diabetic mice. (A, B) The mRNA and protein expression of ATF4 in heart tissues was determined by RT-qPCR and western blotting. LVEF (C) and LVFS (D) were detected by M-mode echocardiography. (E) Representative images of myocardial sections subjected to H&E staining and Masson's staining. (F) Apoptosis in cardiac tissues was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labelling assay. (G) Western blotting analysis of collagen I and collagen III protein abundance in heart tissues. Data are presented as the mean ± SD (n = 5). **P < 0.01, ***P < 0.001.

Fig 5: Inhibition of ATF4 attenuates apoptosis, oxidative stress, and fibrosis in HG-exposed cardiomyocytes. (A) ATF4 level in HL-1 cells after exposure to HG was determined by RT-qPCR. (B) The mRNA level of ATF4 in HL-1 cells transfected with sh-ATF4 was detected by RT-qPCR. (C) Cell viability was detected by MTT assay. (D) Flow cytometry analysis of cell apoptosis. (E) SOD activity, (F) GSH-Px activity, (G) MDA level in HL-1 cells were determined. (H) DCFH-DA staining for measurement of ROS release from HL-1 cells. Data are presented as the mean ± SD (n = 3). **P < 0.01, ***P < 0.001.