DPP4 Inhibition, NPY1-36, PYY1-36, SDF-1α, and a Hypertensive Genetic Background Conspire to Augment Cell Proliferation and Collagen Production: Effects That Are Abolished by Low Concentrations of 2-Methoxyestradiol

The Bidirectional Relationship of NPY and Mitochondria in Energy Balance Regulation

Energy balance is regulated by several hormones and peptides, and neuropeptide Y is one of the most crucial in feeding and energy expenditure control. NPY is regulated by a series of peripheral nervous and humoral signals that are responsive to nutrient sensing, but its role in the energy balance is also intricately related to the energetic status, namely mitochondrial function. During fasting, mitochondrial dynamics and activity are activated in orexigenic neurons, increasing the levels of neuropeptide Y. By acting on the sympathetic nervous system, neuropeptide Y modulates thermogenesis and lipolysis, while in the peripheral sites, it triggers adipogenesis and lipogenesis instead. Moreover, both central and peripheral neuropeptide Y reduces mitochondrial activity by decreasing oxidative phosphorylation proteins and other mediators important to the uptake of fatty acids into the mitochondrial matrix, inhibiting lipid oxidation and energy expenditure. Dysregulation of the neuropeptide Y system, as occurs in metabolic diseases like obesity, may lead to mitochondrial dysfunction and, consequently, to oxidative stress and to the white adipose tissue inflammatory environment, contributing to the development of a metabolically unhealthy profile. This review focuses on the interconnection between mitochondrial function and dynamics with central and peripheral neuropeptide Y actions and discusses possible therapeutical modulations of the neuropeptide Y system as an anti-obesity tool.

Proline oxidase silencing inhibits p53-dependent apoptosis in MCF-7 breast cancer cells

Proline oxidase (POX) is mitochondrial proline-degrading enzyme of dual apoptosis/survival function. POX expression and proline availability are considered an underlying mechanism for differential POX functions. The mechanism for POX-dependent regulation of cell death/survival was studied in wild-type (MCF-7^WT) and shRNA POX-silenced breast cancer cells (MCF-7^iPOX). Proline concentration and proteomic analyses were determined by LC/MS/QTOF and LC/MS/ORBITRA, respectively. Inhibition of collagen biosynthesis (proline utilizing process) by 2-methoxyestradiol (2ME) contributed to induction of apoptosis in MCF-7^WT cells, as detected by increase in the expression of active caspase-3, -9 and p53. The process was not shown in MCF-7^iPOX. In MCF-7^iPOX cells prolidase activity and expression as well as proline concentration were drastically increased, compared to MCF-7^WT cells. Down-regulation of p53 in MCF-7^iPOX cells was corroborated by proteomic analysis showing decrease in the expression of p53-related proteins. The mechanism for down-regulation of p53 expression in MCF-7^iPOX cells was found at the level of p53-PEPD complex formation that was counteracted by hydrogen peroxide treatment. In this study, we found that silencing POX modulate pro-survival phenotype of MCF-7 cells and suggest that the mechanism of this process undergoes through down-regulation of p53-dependent signaling.

Long-Term Dipeptidyl Peptidase 4 Inhibition Worsens Hypertension and Renal and Cardiac Abnormalities in Obese Spontaneously Hypertensive Heart Failure Rats

Background The long-term effects of dipeptidyl peptidase 4 (DPP4) inhibitors on blood pressure and cardiovascular and renal health remain controversial. Herein, we investigated the extended (>182 days) effects of DPP4 inhibition in a model of spontaneous hypertension, heart failure, diabetes mellitus, obesity and hyperlipidemia. Methods and Results Adult obese spontaneously hypertensive heart failure rats (SHHF) were implanted with radio transmitters for measurement of arterial blood pressures. Two weeks later, SHHF were randomized to receive either a DPP4 inhibitor (sitagliptin, 80 mg/kg per day in drinking water) or placebo. At the end of the radiotelemetry measurements, renal and cardiac function and histology, as well as other relevant biochemical parameters, were assessed. For the first 25 days, mean arterial blood pressures were similar in sitagliptin-treated versus control SHHF; afterwards, mean arterial blood pressures increased more in sitagliptin-treated SHHF (P<0.000001). The time-averaged mean arterial blood pressures from day 26 through 182 were 7.2 mm Hg higher in sitagliptin-treated SHHF. Similar changes were observed for systolic (8.6 mm Hg) and diastolic (6.1 mm Hg) blood pressures, and sitagliptin augmented hypertension throughout the light-dark cycle. Long-term sitagliptin treatment also increased kidney weights, renal vascular resistances, the excretion of kidney injury molecule-1 (indicates injury to proximal tubules), renal interstitial fibrosis, glomerulosclerosis, renal vascular hypertrophy, left ventricular dysfunction, right ventricular degeneration, and the ratios of collagen IV/collagen III and collagen IV/laminin in the right ventricle. Conclusions These findings indicate that, in some genetic backgrounds, long-term DPP4 inhibitor treatment is harmful and identify an animal model to study mechanisms of, and test ways to prevent, DPP4 inhibitor-induced pathological conditions.

The cardioprotective and anxiolytic effects of Chaihujialonggumuli granule on rats with anxiety after acute myocardial infarction is partly mediated by suppression of CXCR4/NF-κB/GSDMD pathway

AIMS

Over-expression of CXCR4 activates nuclear translocation of NF-κB, induces high expression of NLRP3, GSDMD, IL-1β and IL-18, which promotes severe inflammatory response following myocardial infarction. Previous studies revealed inflammation induces anxiety after myocardial infarction. The Chaihujialonggumuli granule has anti-inflammatory properties and could tranquillize mind. But the mechanism of its efficacy remains unknown. This study was to investigate the possible mechanism of BFG on cardioprotective and anxiolytic.

METHODS

The expression of CXCR4, NF-κB, NLRP3and GSDMD was measured with western-blot, QRT-PCR. The expression location of CXCR4, NLRP3, GSDMD were determined by immunohistochemistry. IL-1β、IL-18 in the peripheral blood were measured by ELISA. HE staining, Masson staining and transmission electron microscopy were used to observe morphological changes of cardiomyocytes. Echocardiography was used to assess cardiac function after cardiac surgery. Elevated cross maze test and open field test were used to evaluate behaviours. Western blot was used to detect the protein expressions of 5-HT, DA, IL-1β, IL-18 and neuron damage was investigated by Nissl staining in the hippocampus.

RESULTS

The up-regulation of CXCR4, NF-κB, NLRP3 and GSDMD were found in the infarcted area after left coronary artery ligation. Pathological staining and analysis showed that more severe inflammatory cytokines infiltration, myocardial fibrosis, were found in myocardial tissue of the complex group rats. And when compared to the sham group, the levels of IL-1β, IL-18 was increased of the complex group in both peripheral blood and brain. Behavioural test and echocardiography indicated that the rats in complex group exploration behaviours was significantly reduced, and with poor cardiac functional recovery. The AMD3100 had an inhibitory impact of CXCR4 on the activition of its downstream effectors, alleviating inflammatory reaction. Furthermore, the BFG decreased the expression level of CXCR4, NF-κB, GSDMD, NLRP3 in the infarcted area after myocardial infarction, when compared to the complex group. The assays in the brain indicated the BFG suppressed expression and activity of IL-1β, IL-18, and improved 5-HT and DA synthesis.

CONCLUSIONS

In sum, our study indicated that BFG may reduce inflammation, treat co-existing anxiety after myocardial infarction through inhibition of CXCR4/NF-κB/GSDMD signalling.