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Sepsis can cause sepsis-associated encephalopathy (SAE), but whether SAE was induced or exacerbated by ferroptosis remains unknown. In this study, the rat sepsis model was constructed using the cecal ligation and puncture method. The blood–brain barrier (BBB) permeability was measured by Evans blue dye (EBD) in vivo. The levels of ROS, Fe ion, MDA, GSH, and GPX4 were assessed by enzyme-linked immunosorbent assay (ELISA). The exosomes isolated from serum were cultured with bEnd.3 cells for the in vitro analysis. Moreover, bEnd.3 cells cultured with 100 μM FeCl3 (iron-rich) were to simulate ferroptosis stress. The cell viability was evaluated by Cell Counting Kit-8 (CCK-8) assay. A dual-luciferase reporter gene assay was performed to confirm the relationship between miR-9-5p with NEAT1, TFRC, and GOT1. In vivo, it is found that BBB permeability was damaged in model rats. Level of ROS, Fe ion, and MDA was increased, and level of GSH and GPX4 was decreased, which means ferroptosis was induced by sepsis. Exosome-packaged NEAT1 in serum was significantly upregulated in model rats. In vitro, it is found that NEAT1 functions as a ceRNA for miR-9-5p to facilitate TFRC and GOT1 expression. Overexpression of NEAT1 enhanced ferroptosis stress in bEnd.3 cells. Increased miR-9-5p alleviated sepsis-induced ferroptosis by suppressing the expression of TFRC and GOT1 both in vivo and in vitro. In conclusion, these findings suggest that sepsis induced high expression of serous exosome-derived NEAT1, and it might exacerbate SAE by promoting ferroptosis through regulating miR-9-5p/TFRC and GOT1 axis.

Objective: The aim of this study was to verify the protective effect of hypertonic saline (HS) on brain endothelial cells under hypoxic conditions and the relevant underlying mechanism. Methods: bEnd.3 cells were treated with oxygen-glucose deprivation (OGD)-induced injury. To measure HS performance, cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt assay, and cell apoptosis was assessed by flow cytometry and Terminal deoxynucleotidyl transferase UTP nick-end labeling staining. RNA-seq was performed to assess the expression profiles and screen the candidate genes that participated in OGD-induced injury and the HS protective effect. Quantitative real-time polymerase chain reaction (qPCR) and western blot analysis were used to confirm the expression of candidate genes, and enzyme-linked immunosorbent assay was used to measure the level of interleukin (IL)-1β. Overexpression analyses were performed to confirm the functions of the differentially expressed genes. Results: HS with a concentration of 40 mmol/L NaCl had an obvious protective effect on bEnd.3 cells after OGD-induced injury, resulting in increased cell viability and a smaller percentage of apoptotic cells. According to the RNA-seq results, epidermal growth factor receptor (EGFR) was chosen as the differentially expressed gene target in this study. The qPCR and western blot analyses further confirmed that the levels of EGFR/phosphorylated epidermal growth factor receptor and IL-1β were enhanced after OGD-induced injury, but attenuated after treatment with 40 mmol/L of NaCl HS. Overexpressed EGFR reversed the protective effect of HS that caused low viability and high rates of apoptosis in cells. Conclusion: HS can protect endothelial cells against OGD-induced injury, but is affected by the expression of EGFR/p-EGFR and IL-1β.

The nonpeptide AVE0991 is expected to be a putative new drug for cardiovascular diseases. However, the mechanisms for the cardioprotective actions of AVE0991 are still not fully understood. We planned to determine whether AVE0991 attenuates the angiotensin II (AngII)-induced myocardial hypertrophy and whether these AVE0991 effects involved transforming growth factor beta1 (TGF-beta1) and Smad2. A rat model of neonatal myocardial hypertrophy was induced by AngII. The AngII group significantly increased in protein content, surface area, and [(3)H]leucine incorporation efficiency by cardiomyocytes, compared to those of the control group (P < 0.01). The AngII group also had elevated TGF-beta1 and Smad2 expression (P < 0.01). These AngII-induced changes were significantly attenuated by AVE0991 in a dose-dependent manner. In our study, these actions of AngII (10(-6) mol/l) were significantly inhibited by both concentrations of AVE0991 (10(-5) mol/l and 10(-7) mol/l). Moreover, the high AVE0991 group had significantly better inhibition of myocardial hypertrophy than the low AVE0991 group. Meanwhile, the beneficial effects of AVE0991 were completely abolished when the cardiomyocytes were pretreated with Ang-(1-7) receptor antagonist A-779 (10(-6) mol/l). These results suggested that AVE0991 prevented AngII-inducing myocardial hypertrophy in a dose-dependent fashion, a process that may be associated with the inhibition of TGF-beta1/Smad2 signaling.

Cardiomyocyte stretching has been reported to be a major trigger for brain natriuretic peptide (BNP) release; however, an increase in circulating BNP is observed in patients with acute myocardial ischemia in the absence of increased left ventricular wall stress or cardiomyocyte stretching. In the present study, to investigate the direct and independent effects of acute myocardial ischemia on BNP expression and its mechanism, we established an in vitro glucose-free ischemia and hypoxia injured model of cultured rat cardiomyotes and proved hypoxia upregulated expressions of interleukin-6(il-6) and BNP. Further treatment with il-6 elicited dose- and time-dependent increases in BNP mRNA and protein expression as well as an upregulation in transforming growth factor-β1 (TGF-β1)/Smad2 expression, which was partially suppressed by a neutralizing antibody. In conclusion, our study showed that acute myocardial ischemia can directly upregulate BNP expression at the translational and transcriptional levels through the action of il-6, and this process is associated with the upregulation of TGF-β1/Smad2 signal path.

Summary 1. Previously, we showed that long-term treatment of rats after myocardial infarction (MI) with B-type natriuretic peptide (BNP) prevented ventricular remodelling. However, it is unclear whether long-term BNP treatment affects cardiac hypertrophy and, if so, its mechanism of action. In the present study, we investigated the effects of long-term BNP treatment on cardiac hypertrophy and the molecular mechanisms involved. 2. Cardiac hypertrophy was established in rats by ligation of the left anterior descending coronary artery. After treatment with BNP (5 or 15 μg/kg per day) for 8 weeks, indices of cardiac hypertrophy were determined. In separate in vitro experiments, cardiomyocyte hypertrophy was induced by treatment of cardiomyocytes with 10−6 mol/L angiotensin (Ang) II for 48 h and cell surface area and [3H] incorporation were measured. Transforming growth factor (TGF)-β1 and smad7 mRNA and protein expression in vivo and in vitro were detected using reverse transcription–polymerase chain reaction and western blotting. 3. Long-term BNP treatment dose-dependently attenuated cardiac hypertrophy and improved cardiac function in rats after MI. Furthermore, BNP attenuated the upregulation of TGF-β1 and downregulation of smad7 mRNA and protein expression. The in vitro experiments further proved that BNP inhibited cardiac hypertrophy and changes in the TGF-β1/smad7 pathway, which were completely blocked by the cyclic GMP-dependent protein kinase (PKG) inhibitor, KT5823 (cells were treated with 10−6 mol/L KT5823 for 48 h). 4. The results of the present study demonstrate that long-term treatment of rats with BNP dose-dependently attenuates cardiac hypertrophy and that this is associated with downregulation of TGF-β1 and upregulation of smad7 via PKG signalling. Long-term BNP treatment may be a new therapeutic strategy to prevent cardiac hypertrophy and progression to heart failure.

Although short-term B-type natriuretic peptide (BNP) treatment has been shown to be effective for decompensated congestive heart failure, little is known about the effects of long-term BNP treatment in ventricular remodeling and heart failure in response to myocardial infarction. The aim of the present study was to investigate the effects of long-term BNP treament on ventricular remodeling and heart failure after myocardial infarction in rats. Myocardial infarction was induced by ligating the left anterior descending coronary artery. The surviving rats were randomly divided into four groups: 1) vehicle-treated myocardial infarction group (‘vehicle-treated group’), 2) rats treated with low-dose BNP (‘low BNP group’), 3) rats treated with high-dose BNP (‘high BNP group’), 4) sham-operated group. Eight weeks after the operation, rats were sacrificed. Compared with the sham-operated group, the vehicle-treated group had significantly higher collagen deposition and angiotensin II levels (P < 0.01) and a significantly lower cardiac function (P < 0.05). Both BNP-treated groups had significant improvement of these indexes compared with the vehicle-treated group (P < 0.01). The high BNP group had significantly less collagen deposition and better cardiac function than the untreated and low BNP groups. Moreover, the mRNA and protein expression of TGFβ1 and Smad2 in the vehicle-treated group was significantly higher than in the sham-operated group (P < 0.01). Both BNP-treated groups had a suppression of TGFβ1 and Smad2 expression (P < 0.01). In conclusion, long-term treatment with BNP prevents ventricular remodeling and deterioration of cardiac function in a dose-dependent fashion, a process that may be associated with the inhibition of TGFβ1/ Smad2 signaling.