Reverse Apolipoprotein A-I Mimetic Peptide R-D4F Inhibits Neointimal Formation following Carotid Artery Ligation in Mice

Identification of key differential genes in intimal hyperplasia induced by left carotid artery ligation

Background

Intimal hyperplasia is a common pathological process of restenosis following angioplasty, atherosclerosis, pulmonary hypertension, vein graft stenosis, and other proliferative diseases. This study aims to screen for potential novel gene targets and mechanisms related to vascular intimal hyperplasia through an integrated microarray analysis of the Gene Expression Omnibus Database (GEO) database.

Material and Methods

The gene expression profile of the GSE56143 dataset was downloaded from the Gene Expression Omnibus database. Functional enrichment analysis, protein-protein interaction (PPI) network analysis, and the transcription factor (TF)-target gene regulatory network were used to reveal the biological functions of differential genes (DEGs). Furthermore, the expression levels of the top 10 key DEGs were verified at the mRNA and protein level in the carotid artery 7 days after ligation.

Results

A total of 373 DEGs (199 upregulated DEGs and 174 downregulated DEGs) were screened. These DEGs were significantly enriched in biological processes, including immune system process, cell adhesion, and several pathways, which were mainly associated with cell adhesion molecules and the regulation of the actin cytoskeleton. The top 10 key DEGs (Ptprc, Fn1, Tyrobp, Emr1, Itgb2, Itgax, CD44, Ctss, Ly86, and Aif1) acted as key genes in the PPI network. The verification of these key DEGs at the mRNA and protein levels was consistent with the results of the above-mentioned bioinformatics analysis.

Conclusion

The present study identified key genes and pathways involved in intimal hyperplasia induced by carotid artery ligation. These results improved our understanding of the mechanisms underlying the development of intimal hyperplasia and provided candidate targets.

D4F prophylaxis enables redox and energy homeostasis while preventing inflammation during hypoxia exposure

Apo-A1 is correlated with conditions like hyperlipidemia, cardiovascular diseases, high altitude pulmonary edema and etc. where hypoxia constitutes an important facet.Hypoxia causes oxidative stress, vaso-destructive and inflammatory outcomes.Apo-A1 is reported to have vasoprotective, anti-oxidative, anti-apoptotic, and anti-inflammatory effects. However, effects of Apo-A1 augmentation during hypoxia exposure are unknown.In this study, we investigated the effects of exogenously supplementing Apo-A1-mimetic peptide on SD rats during hypoxia exposure. For easing the processes of delivery, absorption and bio-availability, Apo-A1 mimetic peptide D4F was used. The rats were given 10 mg/kg BW dose (i.p.) of D4F for 7 days and then exposed to hypoxia. D4F was observed to attenuate both oxidative stress and inflammation during hypoxic exposure. D4F improved energy homeostasis during hypoxic exposure. D4F did not affect HIF-1a levels during hypoxia but increased MnSOD levels while decreasing CRP and Apo-B levels. D4F showed promise as a prophylactic against hypoxia exposure.

The apolipoprotein A-I mimetic peptide, D-4F, restrains neointimal formation through heme oxygenase-1 up-regulation

D‐4F, an apolipoprotein A‐I (apoA‐I) mimetic peptide, possesses distinctly anti‐atherogenic effects. However, the biological functions and mechanisms of D‐4F on the hyperplasia of vascular smooth muscle cells (VSMCs) remain unclear. This study aimed to determine its roles in the proliferation and migration of VSMCs. In vitro, D‐4F inhibited VSMC proliferation and migration induced by ox‐LDL in a dose‐dependent manner. D‐4F up‐regulated heme oxygenase‐1 (HO‐1) expression in VSMCs, and the PI3K/Akt/AMP‐activated protein kinase (AMPK) pathway was involved in these processes. HO‐1 down‐regulation with siRNA or inhibition with zinc protoporphyrin (Znpp) impaired the protective effects of D‐4F on the oxidative stress and the proliferation and migration of VSMCs. Moreover, down‐regulation of ATP‐binding cassette transporter A1 (ABCA1) abolished the activation of Akt and AMPK, the up‐regulation of HO‐1 and the anti‐oxidative effects of D‐4F. In vivo, D‐4F restrained neointimal formation and oxidative stress of carotid arteries in balloon‐injured Sprague Dawley rats. And inhibition of HO‐1 with Znpp decreased the inhibitory effects of D‐4F on neointimal formation and ROS production in arteries. In conclusion, D‐4F inhibited VSMC proliferation and migration in vitro and neointimal formation in vivo through HO‐1 up‐regulation, which provided a novel prophylactic and therapeutic strategy for anti‐restenosis of arteries.

Treatment options for low high-density lipoproteins

PURPOSE OF REVIEW

To examine the current and future therapeutic option of HDL-based therapies.

RECENT FINDINGS

The inverse association between plasma level of high-density lipoprotein cholesterol (HDL-C) is strong and coherent across the population studied. In-vitro and in-vivo studies show the strong biological plausibility for HDL as a therapeutic target. Mendelian randomization does not support HDL-C as a causal (protective) cardiovascular risk factor, and clinical data does not support the concept that raising HDL-cholesterol mass alters the outcomes. Better biomarkers of HDL function are being examined in the clinical trials. These include cellular cholesterol efflux, antioxidant and anti-inflammatory effects, effects on vascular endothelial cells (inflammation and nitric oxide release) and endothelial progenitor cells. Novel therapeutic agents that alter HDL function are in advanced phase 3 trials and in early preclinical trials. These include inhibitors of cholesteryl ester transfer protein, reconstituted proteoliposomes, apolipoprotein A-I and HDL mimetic peptides and small molecules that increase apo A-I production rate.

SUMMARY

Targeting HDL-C has, to date, not led to changes in the cardiovascular outcomes. Novel therapeutic advances target the HDL function. In keeping with the recent 2013 American College of Cardiology/American Heart Association Guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults, the major focus of prevention lies with LDL-cholesterol reduction.