The Effects of Bradykinin B1 Receptor Antagonism on the Myocardial and Vascular Consequences of Hypertension in SHR Rats

Bifidobacterium longum CCFM752 prevented hypertension and aortic lesion, improved antioxidative ability, and regulated the gut microbiome in spontaneously hypertensive rats

Oxidative stress and gut dysbiosis are important risk factors for hypertension. In this study, the preventive effect of Bifidobacterium longum CCFM752 (CCFM752) on hypertension was evaluated. 5-week-old spontaneously hypertensive rats (SHR) were treated with vehicle or CCFM752 (1.0 × 10⁹ CFU day^-1) for 12 weeks. The increase in systolic blood pressure and diastolic blood pressure was significantly prevented by CCFM752 treatment. Simultaneously, CCFM752 prevented aortic fibrosis and hypertrophy and increased aortic endothelial nitric oxide synthase (eNOS) activity. CCFM752 presented an antioxidative effect by inhibiting aortic NADPH oxidase activation and increasing aortic and serum catalase activity, and reducing aortic reactive oxygen species (ROS). The gut dysbiosis of SHR, including the increased Firmicutes/Bacteroidetes ratio, decreased Actinobacteria as well as reduced α-diversity, were restored by CCFM752. CCFM752 also increased the prevalence of Bifidobacterium and Lactobacillus, while decreasing Turicibacter at the genus level. Furthermore, serum metabolomic analysis revealed that CCFM752 up-regulated serum proline and pyridoxamine 5'-phosphate, both of which were negatively correlated with blood pressure. In conclusion, the positive impact of CCFM752 on the gut microbiota may contribute to the antioxidative effect as well as its preventive effect on hypertension.

Neuroinflammation and Its Impact on the Pathogenesis of COVID-19

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The clinical manifestations of COVID-19 include dry cough, difficult breathing, fever, fatigue, and may lead to pneumonia and respiratory failure. There are significant gaps in the current understanding of whether SARS-CoV-2 attacks the CNS directly or through activation of the peripheral immune system and immune cell infiltration. Although the modality of neurological impairments associated with COVID-19 has not been thoroughly investigated, the latest studies have observed that SARS-CoV-2 induces neuroinflammation and may have severe long-term consequences. Here we review the literature on possible cellular and molecular mechanisms of SARS-CoV-2 induced-neuroinflammation. Activation of the innate immune system is associated with increased cytokine levels, chemokines, and free radicals in the SARS-CoV-2-induced pathogenic response at the blood-brain barrier (BBB). BBB disruption allows immune/inflammatory cell infiltration into the CNS activating immune resident cells (such as microglia and astrocytes). This review highlights the molecular and cellular mechanisms involved in COVID-19-induced neuroinflammation, which may lead to neuronal death. A better understanding of these mechanisms will help gain substantial knowledge about the potential role of SARS-CoV-2 in neurological changes and plan possible therapeutic intervention strategies.

Mitochondrial protective effects of PARP-inhibition in hypertension-induced myocardial remodeling and in stressed cardiomyocytes

AIMS

During oxidative stress mitochondria become the main source of endogenous reactive oxygen species (ROS) production. In the present study, we aimed to clarify the effects of pharmacological PARP-1 inhibition on mitochondrial function and quality control processes.

MAIN METHODS

L-2286, a quinazoline-derivative PARP inhibitor, protects against cardiovascular remodeling and heart failure by favorable modulation of signaling routes. We examined the effects of PARP-1 inhibition on mitochondrial quality control processes and function in vivo and in vitro. Spontaneously hypertensive rats (SHRs) were treated with L-2286 or placebo. In the in vitro model, 150 μM H2O2 stress was applied on neonatal rat cardiomyocytes (NRCM).

KEY FINDINGS

PARP-inhibition prevented the development of left ventricular hypertrophy in SHRs. The interfibrillar mitochondrial network were less fragmented, the average mitochondrial size was bigger and showed higher cristae density compared to untreated SHRs. Dynamin related protein 1 (Drp1) translocation and therefore the fission of mitochondria was inhibited by L-2286 treatment. Moreover, L-2286 treatment increased the amount of fusion proteins (Opa1, Mfn2), thus preserving structural stability. PARP-inhibition also preserved the mitochondrial genome integrity. In addition, the mitochondrial biogenesis was also enhanced due to L-2286 treatment, leading to an overall increase in the ATP production and improvement in survival of stressed cells.

SIGNIFICANCE

Our results suggest that the modulation of mitochondrial dynamics and biogenesis can be a promising therapeutical target in hypertension-induced myocardial remodeling and heart failure.

Effects of bradykinin on proliferation, apoptosis, and cycle of glomerular mesangial cells via the TGF-β1/Smad signaling pathway

We aimed to assess the effects of bradykinin (BK) on the proliferation, apoptosis, and cycle of glomerular mesangial cells via the transforming growth factor-β 1 (TGF-β1)/Smad signaling pathway. Rat glomerular mesangial cells, HBZY-1, were divided into normal group (untreated), model group (5 ng/L TGF-β1), BK group (5 ng/L TGF-β1 + 1 ng/L BK), and inhibitor group [5 ng/L TGF-β1 + 1 ng/L LY2109761 (TGF-β1-specific inhibitor)]. The cell proliferation, cycle, apoptosis, expression of type I collagen (Col-1), and protein expressions of Col-1, TGF-β1, and phosphorylated Smad2 (p-Smad2) were detected by EdU labeling, flow cytometry, acridine orange/ethidium bromide (AO/EB) dual staining, immunofluorescence assay, and Western blotting, respectively. Compared with the normal group, the cell proliferation rate (P = 0.02) and protein expression levels of Col-1 (P = 0.02), TGF-β1 (P = 0.01), p-Smad2 (P = 0.02), and p-Smad7 (P = 0.00) in the model group significantly increased, and apoptosis rate (P = 0.01) significantly decreased. Compared with the model group, the BK and inhibitor groups significantly decreased in proliferation rate (P = 0.01) and protein expression levels of Col-1 (P = 0.01), TGF-β1 (P = 0.01), and p-Smad2 (P = 0.00). Also, they were significantly elevated in apoptosis rate (P = 0.02) and p-Smad7 protein expression (P = 0.02). BK regulates the proliferation, apoptosis, and the cycle of glomerular mesangial cells by inhibiting the TGF-β1/Smad signaling pathway.

BGP-15 Protects against Heart Failure by Enhanced Mitochondrial Biogenesis and Decreased Fibrotic Remodelling in Spontaneously Hypertensive Rats

Heart failure (HF) is a complex clinical syndrome with poor clinical outcomes despite the growing number of therapeutic approaches. It is characterized by interstitial fibrosis, cardiomyocyte hypertrophy, activation of various intracellular signalling pathways, and damage of the mitochondrial network. Mitochondria are responsible for supplying the energy demand of cardiomyocytes; therefore, the damage of the mitochondrial network causes cellular dysfunction and finally leads to cell death. BGP-15, a hydroxylamine derivative, is an insulin-sensitizer molecule and has a wide range of cytoprotective effects in animal as well as in human studies. Our recent work was aimed at examining the effects of BGP-15 in a chronic hypertension-induced heart failure model. 15-month-old male SHRs were used in our experiment. The SHR-Baseline group represented the starting point (n = 7). Animals received BGP-15 (SHR-B, n = 7) or placebo (SHR-C, n = 7) for 18 weeks. WKY rats were used as age-matched normotensive controls (n = 7). The heart function was monitored by echocardiography. Histological preparations were made from cardiac tissue. The levels of signalling proteins were determined by Western blot. At the end of the study, systolic and diastolic cardiac function was preserved in the BGP-treated animals. BGP-15 decreased the interstitial collagen deposition via decreasing the activity of TGFβ/Smad signalling factors and prevented the cardiomyocyte hypertrophy in hypertensive animals. BGP-15 enhanced the prosurvival signalling pathways (Akt/Gsk3β). The treatment increased the activity of MKP1 and decreased the activity of p38 and JNK signalling routes. The mitochondrial mass of cardiomyocytes was also increased in BGP-15-treated SHR animals due to the activation of mitochondrial biogenesis. The mitigation of remodelling processes and the preserved systolic cardiac function in hypertension-induced heart failure can be a result-at least partly-of the enhanced mitochondrial biogenesis caused by BGP-15.