Impact of Insulin-like Growth Factor-I on Migration, Proliferation and Akt-ERK Signaling in Early and Late-passages of Vascular Smooth Muscle Cells

Vascular Smooth Muscle FTO Promotes Aortic Dissecting Aneurysms via m6A Modification of Klf5

Background: Aortic dissecting aneurysm (ADA) represents an aortic remodeling disease with a high mortality rate. Fat mass and obesity-associated protein (FTO) exerts RNA demethylation function to regulate gene expression related to stem cell differentiation, DNA damage repair, and tumorigenesis, but the role of FTO in ADA is still unclear.

Methods: The expression and location of FTO in 43 ADA tissues and 11 normal tissues were determined by RT-qPCR, WB, immunohistochemistry, and immunofluorescence staining. Detecting proliferation and migration of VSMCs. M6A methylated RNA immuno-precipitation qRT-PCR and dual luciferase reporter assay were performed for determining m6A level and interaction between m6A modulation and Klf5 mRNA, respectively.

Results: FTO are highly expressed in VSMCs. FTO was positively correlated with BMI, triglyceride, and D-dimer (all P < 0.05). Functionally, both AngII-induced FTO expression and over expression of FTO promote cell proliferation and migration, whereas knockdown of FTO inhibits these functions. Mechanically, we identified Krüppel-like factor 5 (Klf5) as a target of FTO mediating m6A modification. Overexpression of FTO reduced m6A modification on Klf5 mRNA and promoted Klf5 mRNA expression. Furthermore, the p-GSK3β and Klf5 levels increased after FTO overexpression. Finally, knockdown of FTO suppresses the p-GSK3β levels and Klf5 expression regardless of AngII treatment.

Conclusions: Our study revealed that FTO expression significantly contributes to the phenotype conversion of VSMCs and the ADA by the demethylation function (m6A), thereby providing a novel therapeutic target.

miR-18a-5p Promotes Proliferation and Migration of Vascular Smooth Muscle Cells by Activating the AKT/Extracellular Regulated Protein Kinases (ERK) Signaling Pathway

Background

microRNAs (miRNAs) play important roles in abnormal proliferation and migration of vascular smooth muscle cells (VSMCs), which lead to restenosis in coronary artery disease. Nevertheless, the role of miR-18a-5p and how it works in VSMCs remain unknown.

Material/Methods

miR-18a-5p expression was determined by fluorescence quantitative real-time polymerase chain reaction (qRT-PCR) analysis of tissues from 20 patients with stent restenosis, and rats with carotid artery injury, as well as VSMCs. A cell viability assay was used to measure cell proliferation. Cell migration abilities were assessed by transwell migration assay and wound healing assays. To identify miR-18a-5p targets, a dual-luciferase reporter assay was performed. Western blot analysis and immunofluorescence techniques were used to assess the protein expression levels of AKT and ERK. The rescue effects of miR-18a-5p on the proliferation or migration of VSMCs were evaluated after exposure to the AKT inhibitor MK-2206 and ERK inhibitor PD98059.

Results

The expression level of miR-18a-5p was significantly higher in the blood serum of patients with stent restenosis and in rats with carotid artery injury, and the expression of AKT and ERK was higher after carotid artery injury. The proliferation and migration abilities of VSMCs were accelerated by the overexpression of miR-18a-5p. It was found that miR-18a-5p directly modulates AKT/ERK signaling. Upregulated miR-18a-5p increased the protein expression levels of AKT and ERK and we found a positive correlation between miR-18a-5p expression level and expression of AKT and ERK. Additionally, the promoting effect of miR-18a-5p on VSMCs proliferation, migration, and invasion was reversed by ERK inhibitor or AKT inhibitor.

Conclusions

miR-18a-5p can promote proliferation of VSMCs by activating the AKT/ERK signaling pathway.

Hormetic dose response to L-ascorbic acid as an anti-cancer drug in colorectal cancer cell lines according to SVCT-2 expression

_L-Ascorbic acid (vitamin C, AA) exhibits anti-cancer effects with high-dose treatment through the generation of reactive oxygen species (ROS) and selective damage to cancer cells. The anti-cancer effects of _L-ascorbic acid are determined by sodium-dependent vitamin C transporter 2 (SVCT-2), a transporter of _L-ascorbic acid. In this study, we demonstrate that _L-ascorbic acid treatment showed efficient anti-cancer activity in cell lines with high expression levels of SVCT-2 for a gradient concentration of _L-ascorbic acid from 10 μM −2 mM. However, in low SVCT-2 expressing cell lines, high-dose _L-ascorbic acid (>1 mM) showed anti-cancer effects but low-dose (<10 μM) treatment induced cell proliferation. Such conflicting results that depend on the concentration are called a hormetic dose response. A hormetic dose response to low-dose _L-ascorbic acid was also observed in high SVCT-2 expressing cell lines in the presence of a SVCT family inhibitor. Insufficient uptake of _L-ascorbic acid in low SVCT-2 expressing cancer cell lines cannot generate sufficient ROS to kill cancer cells, resulting in the hormetic response. Molecular analysis confirmed the increased expression of cancer proliferation markers in the hormetic dose response. These results suggest that _L-ascorbic exhibits a biphasic effect in cancer cells depending on SVCT-2 expression.

Potential skin involvement in ALS: revisiting Charcot's observation - a review of skin abnormalities in ALS

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting motor neurons of the brain and spinal cord, leading to progressive paralysis and death. Interestingly, many skin changes have been reported in ALS patients, but never as yet fully explained. These observations could be due to the common embryonic origin of the skin and neural tissue known as the ectodermal germ layer. Following the first observation in ALS patients' skin by Dr Charcot in the 19th century, in the absence of bedsores unlike other bedridden patients, other morphological and molecular changes have been observed. Thus, the skin could be of interest in the study of ALS and other neurodegenerative diseases. This review summarizes skin changes reported in the literature over the years and discusses about a novel in vitro ALS tissue-engineered skin model, derived from patients, for the study of ALS.

Bisdemethoxycurcumin inhibits PDGF-induced vascular smooth muscle cell motility and proliferation

SCOPE

A key event in the development of plaque in the arteries is the migration and proliferation of smooth muscle cells (SMCs) from the media to the intima of the blood vessel. This study was conducted to evaluate the effects of bisdemethoxycurcumin (BC), a naturally occurring structural analog of curcumin (CC), on platelet-derived growth factor (PDGF)-stimulated migration and proliferation of SMCs.

METHODS AND RESULTS

CC and BC were synthesized by condensing acetyl acetone with vanillin and 4-hydroxybenzaldehyde, respectively. SMCs isolated from adult rat aorta were stimulated with PDGF in the presence or absence of CC or BC following which, cell migration and proliferation were assessed by monolayer wound healing assay and [(3) H]-thymidine incorporation respectively. PDGF-stimulated phosphorylation of PDGF receptor-β and its downstream effectors Akt and ERK were assessed by Western blotting. Intracellular reactive oxygen species was assessed using the fluorescent dye 5-(6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate. BC elicited a concentration-dependent inhibition of PDGF-stimulated phosphorylation of PDGF receptor-β, Akt and Erk as well as the PDGF-stimulated SMC migration and proliferation. BC was more potent than CC in inhibiting migration and proliferation and suppressing PDGF-signaling in SMCs. Both compounds were equipotent in inhibiting PDGF-stimulated generation of intracellular reactive oxygen species.

CONCLUSION

BC may be of potential use in the prevention or treatment of vascular disease.

Engineered insulin-like growth factor-1 for improved smooth muscle regeneration

Insulin-like growth factor-1 (IGF-1) has been shown to induce potent mitogenic responses in various cell types, yet its sustained local delivery is still an underdeveloped domain in the clinic. We report here an engineered IGF-1 that facilitates extended local delivery to a site through its immobilization capacity within fibrin. Through recombinant fusion with a substrate sequence tag derived from α(2)-plasmin inhibitor (α(2)PI(1-8)), the resulting variant, α(2)PI(1-8)-IGF-1, was covalently incorporated into fibrin matrices during normal thrombin/factor XIIIa-mediated polymerization. Bioactivity of the variant was confirmed to be equivalent to wild type (WT) IGF-1 via IGF-1 receptor phosphorylation and cell proliferation studies in urinary tract-derived cells in 2-D. Assessment of functional retention within 3-D fibrin matrices demonstrated that incorporation of α(2)PI(1-8)-IGF-1 induced a 1.3- and 1.5-fold more robust proliferative response in smooth muscle cells (SMCs) than WT IGF-1 and negative control matrices, respectively, when release was not contained. Sustained α(2)PI(1-8)-IGF-1 availability at bladder lesion sites in vivo evoked a considerable increase in SMC proliferation and a favorable host tissue response after 28 days in rats. We conclude that the sustained local IGF-1 availability from fibrin provided by our variant protein enhances smooth muscle regeneration better than the WT form of the protein.

Common inflammatory mediators orchestrate pathophysiological processes in rheumatoid arthritis and atherosclerosis

RA is characterized by a systemic inflammatory state, in which immune cells and soluble mediators play a crucial role. These inflammatory processes resemble those in other chronic inflammatory diseases, such as atherosclerosis. The chronic systemic inflammation in RA can be considered as an independent risk factor for the development of atherosclerosis, and represents an important field to investigate the reasons of the increase of acute cardiovascular events in RA. In the present review, we focused on several mediators of autoimmunity, inflammation and endothelial dysfunction, which can be considered the most promising targets to prevent atherogenesis in RA. Among several mediators, the pro-inflammatory cytokine TNF-alpha has been shown as a crucial factor to induce atherosclerosis in RA patients.

Intracellular redox status and oxidative stress: implications for cell proliferation, apoptosis, and carcinogenesis

Oxidative stress can be defined as the imbalance between cellular oxidant species production and antioxidant capability. Reactive oxygen species (ROS) are involved in a variety of different cellular processes ranging from apoptosis and necrosis to cell proliferation and carcinogenesis. In fact, molecular events, such as induction of cell proliferation, decreased apoptosis, and oxidative DNA damage have been proposed to be critically involved in carcinogenesis. Carcinogenicity and aging are characterized by a set of complex endpoints, which appear as a series of molecular reactions. ROS can modify many intracellular signaling pathways including protein phosphatases, protein kinases, and transcription factors, suggesting that the majority of the effects of ROS are through their actions on signaling pathways rather than via non-specific damage of macromolecules; however, exact mechanisms by which redox status induces cells to proliferate or to die, and how oxidative stress can lead to processes evoking tumor formation are still under investigation.