Apoptosis and calcification of vascular endothelial cell under hyperhomocysteinemia. Med Oncol. 2015;32:403. [PMID: 25476479 DOI: 10.1007/s12032-014-0403-z]

Spatial confinement modulates endothelial cell behavior and traction force in 3D hydrogel microgrooves

The mechanical environment of vascular endothelial cells (ECs) encompasses a wide range of curvatures due to variations in blood vessel diameters. Integrins, key mediators of cell-matrix interactions, establish connections between the extracellular matrix and the actin cytoskeleton, influencing diverse cellular behaviors. In this study, we explored the impact of spatial confinement on human umbilical vein ECs (HUVECs) cultured within three-dimensional hydrogel microgrooves of varying curvatures and the underlying role of integrins in mediating cellular responses. Employing maskless lithography, we successfully fabricated precise and wall curvatures-controlled hydrogel microgrooves, conferring spatial constraints on the cells. Our investigations revealed substantial alterations in HUVEC behavior within the hydrogel microgrooves with varying sidewall curvatures, marked by reduced cell size, enhanced orientation, and increased apoptosis. Interestingly, microgroove curvature emerged as a crucial factor influencing cell orientation and apoptosis, with rectangular microgrooves eliciting distinct changes in cell orientation, while ring-form microgrooves exhibited higher apoptosis rates. The side-wall effect in the 20 μm region near the microgroove wall had the greatest influence on cell orientation and apoptosis. HUVECs within the microgrooves exhibited elevated integrin expression, and inhibition of αV-integrin by cilengitide significantly curtailed cell apoptosis without affecting proliferation. Additionally, integrin-mediated cell traction force closely correlated with the spatial confinement effect. Cilengitide not only reduced integrin and focal adhesion expression but also attenuated cell traction force and cytoskeletal actin filament alignment. Overall, our findings elucidate the spatial confinement of ECs in hydrogel microgrooves and underscores the pivotal role of integrins, particularly αV-integrin, in mediating cell traction force and apoptosis within this microenvironment.

Epigenetic Regulation by microRNAs in Hyperhomocysteinemia-Accelerated Atherosclerosis

Increased serum levels of homocysteine (Hcy) is a risk factor for cardiovascular disease and is specifically linked to various diseases of the vasculature such as atherosclerosis. However, the precise mechanisms by which Hcy contributes to this condition remain elusive. During the development of atherosclerosis, epigenetic modifications influence gene expression. As such, epigenetic modifications are an adaptive response to endogenous and exogenous factors that lead to altered gene expression by methylation and acetylation reactions of different substrates and the action of noncoding RNA including microRNAs (miRNAs). Epigenetic remodeling modulates cell biology in both physiological and physiopathological conditions. DNA and histone modification have been identified to have a crucial role in the progression of atherosclerosis. However, the potential role of miRNAs in hyperHcy (HHcy)-related atherosclerosis disease remains poorly explored and might be essential as well. There is no review available yet summarizing the contribution of miRNAs to hyperhomocystein-mediated atherogenicity or their potential as therapeutic targets even though their important role has been described in numerous studies. Specifically, downregulation of miR-143 or miR-125b has been shown to regulate VSCMs proliferation in vitro. In preclinical studies, downregulation of miR-92 or miR195-3p has been shown to increase the accumulation of cholesterol in foam cells and increase macrophage inflammation and atherosclerotic plaque formation, respectively. Another preclinical study found that there is a reciprocal regulation between miR-148a/152 and DNMT1 in Hcy-accelerated atherosclerosis. Interestingly, a couple of studies have shown that miR-143 or miR-217 may be used as potential biomarkers in patients with HHcy that may develop atherosclerosis. Moreover, the current review will also update current knowledge on miRNA-based therapies, their challenges, and approaches to deal with Hcy-induced atherosclerosis.

Effects of individualized administration of folic acid on prothrombotic state and vascular endothelial function with H-type hypertension: A double-blinded, randomized clinical cohort study

BACKGROUND

Hypertension and hyperhomocysteinemia (HHcy) have long been associated with adverse cardiovascular and cerebrovascular health outcomes. This study evaluated the effect of individualized administration of folic acid (FA) on homocysteine (Hcy) levels, prothrombotic state, and blood pressure (BP) in patients with H-type hypertension (combination of HHcy and hypertension).

METHODS

In this double-blinded, randomized clinical cohort study, 126 patients with H-type hypertension who were treated at our hospital were randomly divided into treatment and control groups (n = 55 each). The control group was treated with oral levamlodipine besylate tablets 2.5 mg and placebo, once a day (in the morning). The treatment group was first treated with oral levamlodipine besylate 2.5 mg and FA tablets 0.8 mg, once a day (in the morning), for 12 weeks. Then, in a second 12-week phase, the FA dose was adjusted using the methylene tetrahydrofolate reductase C677 polymorphism genotype. The levels of Hcy and coagulation factors, prothrombotic state parameters, BP, and adverse drug reactions were compared between the 2 groups.

RESULTS

Pretreatment general patient characteristics, including Hcy levels, were similar between the 2 groups (P > .05). BP and prothrombotic status did not differ before and after the first phase of treatment (P > .05). However, Hcy and endothelin-1 (ET-1) levels decreased, while nitric oxide levels increased significantly in the intervention group (P < .05). In the second phase, after 3 months' treatment with an FA dose adjusted according to methylene tetrahydrofolate reductase C677T genotype, the Hcy and ET-1/NO levels were significantly decreased in the intervention group and were lower than those after the first treatment phase and lower than in the control group (P < .01). BP, D-dimer levels, and fibrinogen scores were significantly lower after the second treatment phase (P < .01). There was no significant difference in the incidence of adverse drug reactions between the 2 groups (P > .05).

CONCLUSIONS

Individualized administration of FA tablets can effectively reduce BP, and Hcy and coagulation factor levels, and significantly improve prothrombotic status in patients with H-type hypertension.

Effects and mechanism of arachidonic acid against TNF-α induced apoptosis of endothelial cells

This study aimed to investigate the effects of arachidonic acid metabolite epoxyeicosatrienoic acid (EETs) in the apoptosis of endothelial cells induced by tumor necrosis factor-alpha (TNF-α). After human umbilical vein endothelial cells were cultured, TNF-α/ActD, 14, 15-EET, and HMR-1098 were added, respectively, into the culture medium. The apoptosis level of endothelial cells was detected by flow cytometry. After TNF-α/ActD induced endothelial cell apoptosis, flow cytometry staining showed that endothelial cell apoptosis increased significantly, and the apoptotic cells were significantly reduced after the addition of 14, 15-EET. However, the apoptotic cells significantly increased after the addition of HMR-1098. Western Blot results showed that the phosphorylation levels of LC3-II and AMPK were increased after TNF-α/ActD induction, and the increase was noticeable after the addition of 14, 15-EET. However, the phosphorylation levels of LC3-II and AMPK significantly decreased after the addition of HMR-1098. The activity of Caspase-8 and -9 decreased significantly after the addition of 14, 15-EET but increased after the addition of HMR-1098. Arachidonic acid can inhibit TNF-α induced endothelial cell apoptosis by upregulating autophagy.

Case Report: Two Novel Frameshift Mutations in SLC20A2 and One Novel Splice Donor Mutation in PDGFB Associated With Primary Familial Brain Calcification

Primary familial brain calcification (PFBC, OMIM#213600), also known as Fahr's disease, is characterized by bilateral and symmetric brain calcification in the basal ganglia (globus pallidus, caudate nucleus, and putamen), thalamus, subcortical white matter, and cerebellum. PFBC can be caused by loss-of-function mutations in any of the six known causative genes. The most common clinical manifestations include movement disorders, cognitive impairment, and neuropsychiatric signs that gradually emerge in middle-aged patients. To broaden the PFBC mutation spectrum, we examined nine members of a family with PFBC and two sporadic cases from clinical departments, and sequenced all PFBC-causative genes in the index case. Two novel frameshift mutations in SLC20A2 [NM_001257180.2; c.806delC, p.(Pro269Glnfs^*49) and c.1154delG, p.(Ser385Ilefs^*70)] and one novel splice donor site mutation (NM_002608.4, c.456+1G>C, r.436_456del) in PDGFB were identified in the patient cohort. c.806delC co-segregated with brain calcification and led to SLC20A2 haploinsufficiency among the affected family members. The c.456+1G>C mutation in PDGFB resulted in aberrant mRNA splicing, thereby forming mature transcripts containing an in-frame 21 base pair (bp) deletion, which might create a stably truncated protein [p.(Val146_Gln152del)] and exert a dominant negative effect on wild-type PDGFB. All three mutations were located in highly conserved regions among multiple species and predicted to be pathogenic, as evaluated by at least eight common genetic variation scoring systems. This study identified three novel mutations in SLC20A2 and PDGFB, which broadened and enriched the PFBC mutation spectrum.

Apoptosis in the Extraosseous Calcification Process

Extraosseous calcification is a pathologic mineralization process occurring in soft connective tissues (e.g., skin, vessels, tendons, and cartilage). It can take place on a genetic basis or as a consequence of acquired chronic diseases. In this last case, the etiology is multifactorial, including both extra- and intracellular mechanisms, such as the formation of membrane vesicles (e.g., matrix vesicles and apoptotic bodies), mitochondrial alterations, and oxidative stress. This review is an overview of extraosseous calcification mechanisms focusing on the relationships between apoptosis and mineralization in cartilage and vascular tissues, as these are the two tissues mostly affected by a number of age-related diseases having a progressively increased impact in Western Countries.

Serum alkaline phosphatase levels and the risk of new-onset diabetes in hypertensive adults

BACKGROUND

The association between alkaline phosphatase (ALP) and incident diabetes remains uncertain. Our study aimed to investigate the prospective relation of serum ALP with the risk of new-onset diabetes, and explore possible effect modifiers, in hypertensive adults.

METHODS

A total 14,393 hypertensive patients with available ALP measurements and without diabetes and liver disease at baseline were included from the China Stroke Primary Prevention Trial (CSPPT). The primary outcome was new-onset diabetes, defined as physician-diagnosed diabetes or use of glucose-lowering drugs during follow-up, or fasting glucose ≥ 7.0 mmol/L at the exit visit. The secondary study outcome was new-onset impaired fasting glucose (IFG), defined as FG < 6.1 mmol/L at baseline and ≥ 6.1 but < 7.0 mmol/L at the exit visit.

RESULTS

Over a median of 4.5 years follow-up, 1549 (10.8%) participants developed diabetes. Overall, there was a positive relation of serum ALP and the risk of new-onset diabetes (per SD increment, adjusted OR, 1.07; 95% CI: 1.01, 1.14) and new-onset IFG (per SD increment, adjusted OR, 1.07; 95% CI: 1.02, 1.14). Moreover, a stronger positive association between baseline ALP (per SD increment) with new-onset diabetes was found in participants with total homocysteine (tHcy) < 10 μmol/L (adjusted OR, 1.24; 95% CI: 1.10, 1.40 vs. ≥ 10 μmol/L: adjusted OR, 1.03; 95% CI: 0.96, 1.10; P-interaction = 0.007) or FG ≥ 5.9 mmol/L (adjusted OR, 1.16; 95% CI: 1.07, 1.27 vs. < 5.9 mmol/L: adjusted OR, 1.00; 95% CI: 0.93, 1.08; P-interaction = 0.009) CONCLUSIONS: In this non-diabetic, hypertensive population, higher serum ALP was significantly associated with the increased risk of new-onset diabetes, especially in those with lower tHcy or higher FG levels. Clinical Trial Registration-URL Trial registration: NCT00794885 (clinicaltrials.gov). Retrospectively registered November 20, 2008.

Melatonin and vitamin E alleviate homocysteine-induced oxidative injury and apoptosis in endothelial cells

A relationship exists between hyperhomocysteinemia and cardiovascular diseases, although the underlying mechanisms are still incompletely defined. One possibility involves a homocysteine (Hcy)-induced increased oxidative stress. Melatonin (Mel) and vitamin E (vitE) are important anti-oxidants. The main purpose of this study was (1) to compare the effect of treatments with Mel, vitE or both, on Hcy-induced apoptosis in human umbilical vein endothelial cells (HUVECs), and (2) to investigate the underlying mechanisms. Cell proliferation assay was carried out by Water Soluble Tetrazolium-1 (WST-1) assay kit. Apoptotic index was calculated by TUNEL Assay. Anti-oxidant parameters were studied by measurement of reactive oxygen species (ROS) and lipid peroxidation (LPO) levels. mRNA and protein expression levels of apoptotic and anti-apoptotic genes and proteins were studied by quantitative real time polymerase chain reaction (qRT-PCR) and Western blotting experiments respectively. The results showed that treatments with Mel, vitE or Mel + vitE suppressed Hcy-induced cell death, with a higher efficiency for the Mel and Mel + vitE treatments. Our results suggests that the mechanisms by which these anti-oxidants protected endothelial cells include the decrease in ROS and LPO levels, an increase in cell migration, the downregulation of pro-apoptotic proteins Cas 3, Cas 9, Cyt C and Bax and the upregulation of anti-apoptotic protein Bcl 2. Collectively, these results revealed the protective role of vitE and Mel against Hcy-induced cell apoptosis, which may add insight into therapeutic approaches to Hcy-induced damages.

Hyperhomocysteinemia induces vascular calcification by activating the transcription factor RUNX2 via Krüppel-like factor 4 up-regulation in mice

One of the main characteristics of atherosclerosis is vascular calcification, which is linked to adverse cardiovascular events. Increased homocysteine (Hcy), a feature of hyperhomocysteinemia, is correlated with advanced vascular calcification and phenotypic switching of vascular smooth muscle cells (VSMCs). Oxidative stress and high phosphate levels also induce VSMC calcification, suggesting that the Krüppel-like factor 4 (KLF4) signaling pathway may also contribute to vascular calcification. In this study, we investigated this possibility and the role and mechanisms of Hcy in vascular calcification. We found that in atherosclerotic apolipoprotein E-deficient (ApoE^-/-) mice, Hcy significantly increases vascular calcification in vivo, as well as VSMC calcification in vitro Of note, the Hcy-induced VSMC calcification was correlated with elevated KLF4 levels. Hcy promoted KLF4 expression in calcified atherosclerotic lesions in vivo and in calcified VSMCs in vitro shRNA-mediated KLF4 knockdown blocked the Hcy-induced up-regulation of runt-related transcription factor 2 (RUNX2) and VSMC calcification. RUNX2 inhibition abolished Hcy-induced VSMC calcification. Using ChIP analysis, we demonstrate that KLF4 interacts with RUNX2, an interaction promoted by Hcy stimulation. Our experiments also revealed that the KLF4 knockdown attenuates Hcy-induced RUNX2 transactivity, indicating that KLF4 is important in modulating RUNX2 transactivity. These findings support a role for Hcy in regulating vascular calcification through a KLF4-RUNX2 interaction and indicate that Hcy-induced, enhanced RUNX2 transactivity increases VSMC calcification. These insights reveal possible opportunities for developing interventions that prevent or manage vascular calcification.

Influences of Sex and Estrogen in Arterial and Valvular Calcification

Vascular and cardiac valvular calcification was once considered to be a degenerative and end stage product in aging cardiovascular tissues. Over the past two decades, however, a critical mass of data has shown that cardiovascular calcification can be an active and highly regulated process. While the incidence of calcification in the coronary arteries and cardiac valves is higher in men than in age-matched women, a high index of calcification associates with increased morbidity, and mortality in both sexes. Despite the ubiquitous portending of poor outcomes in both sexes, our understanding of mechanisms of calcification under the dramatically different biological contexts of sex and hormonal milieu remains rudimentary. Understanding how the critical context of these variables inform our understanding of mechanisms of calcification-as well as innovative strategies to target it therapeutically-is essential to advancing the fields of both cardiovascular disease and fundamental mechanisms of aging. This review will explore potential sex and sex-steroid differences in the basic biological pathways associated with vascular and cardiac valvular tissue calcification, and potential strategies of pharmacological therapy to reduce or slow these processes.

Targeting MTHFR for the treatment of migraines

INTRODUCTION

Migraine is a common neurovascular disorder classified by the World Health Organization as one of the most debilitating diseases. Migraine is a complex disease and is a consequence of an interaction between genetic, epigenetic and environmental factors. The MTHFR gene is one of the few replicated genetic risk factors for migraine and encodes an enzyme that is crucial for the folate and the methionine cycles. Individuals carrying the T allele of the MTHFR C677T polymorphism have increased plasma concentrations of homocysteine which leads to endothelial cell injury and alterations in coagulant properties of blood. Areas covered: This review focuses on the recent advances in genetics and the role of the MTHFR gene and homocysteine metabolism in migraine etiopathogenesis. The article summarizes the potential of targeting MTHFR and homocysteine for disease prevention. Expert opinion: Determination of MTHFR C677T polymorphisms as well as measurement of homocysteine concentrations may be useful to migraine patients, particularly those suffering from migraine with aura. Preliminary studies support the use of folate, vitamin B6 and vitamin B12 for the prevention of migraine. However, the results of these studies await replication in larger randomized controlled clinical trials.

MicroRNA-130a alleviates human coronary artery endothelial cell injury and inflammatory responses by targeting PTEN via activating PI3K/Akt/eNOS signaling pathway

Our study aims to investigate the roles of microRNA-130a (miR-130a) in human coronary artery endothelial cells (HCAECs) injury and inflammatory responses by targeting PTEN through the PI3K/Akt/eNOS signaling pathway. HCAECs were treated with 1.0 mmol/L homocysteine (HCY) and assigned into eight groups: the blank group, the negative control (NC) group, the miR-130a mimics group, the miR-130a inhibitors group, the si-PTEN group, the Wortmannin group, the miR-130a inhibitors + si-PTEN group and the miR-130a mimics + Wortmannin group. Luciferase reporter gene assay was used to validate the relationship between miR-130a and PTEN. The expressions of miR-130a, PTEN and PI3K/Akt/eNOS signaling pathway-related proteins were detected by qRT-PCR assay and Western blotting. MTT assay and Hoechst 33258 staining were adopted to testify cell growth and apoptosis. The NO kit assay was used to detect the NO release. ELISA was conducted to measure serum cytokine levels. Luciferase reporter gene assay confirmed the target relationship between miR-130a and PTEN. Compared with the blank and NC groups, the miR-130a mimics and si-PTEN groups showed significant increases in the expressions of PI3K/Akt/eNOS signaling pathway-related proteins, cell viability and the NO release, while serum cytokine levels and cell apoptosis were decreased; by contrast, an opposite trend was observed in miR-130a inhibitors and Wortmannin groups. However, no significant difference was found in the miR-130a inhibitors + si-PTEN and miR-130a mimics + Wortmannin groups when compared with the blank group. These results indicate that miR-130a could alleviate HCAECs injury and inflammatory responses by down-regulating PTEN and activating PI3K/Akt/eNOS signaling pathway.

Autophagy inhibition enhances isorhamnetin‑induced mitochondria‑dependent apoptosis in non‑small cell lung cancer cells

Isorhamnetin (ISO) is a flavonoid from plants of the Polygonaceae family and is also an immediate metabolite of quercetin in mammals. To date, the anti-tumor effects of ISO and the underlying mechanisms have not been elucidated in lung cancer cells. The present study investigated the inhibitory effects of ISO on the growth of human lung cancer A549 cells. Treatment of the lung cancer cells with ISO significantly suppressed cell proliferation and colony formation. ISO treatment also resulted in a significant increase in apoptotic cell death of A549 cells in a time- and dose-dependent manner. Further investigation showed that the apoptosis proceeded via the mitochondria-dependent pathway as indicated by alteration of the mitochondrial membrane potential, the release of cytochrome C and caspase activation. Of note, treatment with ISO also induced the formation of autophagosomes and light chain 3-II protein in A549 cells. Furthermore, co-treatment with autophagy inhibitors 3-methyladenine and hydroxychloroquine significantly inhibited the ISO-induced autophagy and enhanced the ISO-induced apoptotic cell death in vitro as well as in vivo. Thus, the results of the present study suggested that ISO is a potential anti-lung cancer agent. In addition, the results indicated that the inhibition of autophagy may be a useful strategy for enhancing the chemotherapeutic effect of ISO on lung cancer cells.

Significance of expression of MST1 in homocysteine-induced hepatocyte apoptosis

AIM: To study the role of the mammalian sterile 20-like kinase 1 (MST1) gene in homocysteine-induced hepatocyte apoptosis.

METHODS: Five-week-old C57BL/6J mice of SPF grade were divided into four groups: a normal control group, an ApoE^-/- group, a high methionine diet group, and an intervention group (n = 12 each). In the normal control group, normal mice were fed a normal diet. In the ApoE^-/- group, male ApoE^-/- mice were fed a normal diet. In the high methionine diet group, male ApoE^-/- mice were fed a high methionine diet. In the intervention group, male ApoE^-/- mice were fed a high methionine diet plus folic acid and vitamin B₁₂. Transmission electron microscopy and DAPI staining were used to determine the level of apoptosis in hepatic tissue. qRT-PCR and Western blot were used to determine the expression of MST1. Hepatocytes were then cultured in the presence or absence of homocysteine (100 μmol/L) alone or 100 μmol/L homocysteine plus folic acid and vitamin B₁₂; flow cytometry was used to determine the level of hepatocytes apoptosis, and the expression of MST1 was detected by qRT-PCR and Western blot.

RESULTS: After the mice were fed for 14 wk, serum homocysteine level in the high methionine diet group was 2.3 and 1.9 times as high as that in the normal control group and the ApoE^-/- group (P < 0.01), respectively. Serum homocysteine level in the intervention group was 28% lower than that in the high methionine diet group (P < 0.01). These findings suggest that the model was successfully established. Electron microscopy showed that in the high methionine diet group, there were chromosome swelling or condensation, mitochondrial swelling, marked endoplasmic reticulum swelling and break, which suggested the trend of cell apoptosis in hepatic tissue. Compared with the normal control group and ApoE^-/- group, hepatic apoptosis level in the high methionine diet group was higher. However, hepatic apoptosis level in the intervention group was lower than that in the high methionine diet group. Compared with the normal control group and ApoE^-/- group, the expression of MST1 mRNA and protein in heapatic tissue in the high methionine diet group was upregulated (P < 0.05 or P < 0.01); however, MST1 expression in the intervention group was significantly lower than that in the high methionine diet group (P < 0.05). In vitro, compared with the normal control group, hepatocytes apoptosis level in the homocysteine alone group was significantly higher (P < 0.01); however, hepatocytes apoptosis level in the intervention group was significantly lower than that in the homocysteine alone group (P < 0.05). Compared with the normal control group, the expression of MST1 mRNA and protein in the homocysteine alone group was upregulated (P < 0.01); however, MST1 expression in the intervention group was significantly lower than that in the homocysteine alone group (P < 0.05).

CONCLUSION: MST1 expression is upregulated in homocysteine-induced hepatocyte apoptosis, and folic acid and vitamin B₁₂ can suppress the up-regulation of MST1.