FOXO3a (Forkhead Transcription Factor O Subfamily Member 3a) Links Vascular Smooth Muscle Cell Apoptosis, Matrix Breakdown, Atherosclerosis, and Vascular Remodeling Through a Novel Pathway Involving MMP13 (Matrix Metalloproteinase 13)

Role of cardiolipin in regulating and treating atherosclerotic cardiovascular diseases

Cardiovascular diseases, mainly caused by atherosclerosis, are the leading causes of morbidity and mortality worldwide. Despite the discrepancies in clinical manifestations between different abnormalities, atherosclerosis shares similar pathophysiological processes, such as mitochondrial dysfunction. Cardiolipin (CL) is a conserved mitochondria-specific lipid that contributes to the cristae structure of the inner mitochondrial membrane (IMM). Alterations in the CL, including oxidative modification, reduced quantity, and abnormal localization, contribute to the onset and progression of atherosclerosis. In this review, we summarize the knowledge that CL is involved in the pathogenesis of atherosclerosis. On the one hand, CL and its oxidative modification promote the progression of atherosclerosis via several mechanisms, including oxidative stress, apoptosis, and inflammation in response to stress. On the other hand, CL externalizes to the outer mitochondrial membrane (OMM) and acts as the pivotal "eat-me" signal in mitophagy, removing dysfunctional mitochondria and safeguarding against the progression of atherosclerosis. Given the imbalance between proatherogenic and antiatherogenic effects, we provide our understanding of the roles of the CL and its oxidative modification in atherosclerotic cardiovascular diseases, in addition to potential therapeutic strategies aimed at restoring the CL. Briefly, CL is far more than a structural IMM lipid; broader significances of the evolutionarily conserved lipid need to be explored.

Involvement of Kindlin-1 in cutaneous squamous cell carcinoma

Kindler syndrome (KS) is a rare genodermatosis resulting from loss-of-function mutations in FERMT1, the gene that encodes Kindlin-1. KS patients have a high propensity to develop aggressive and metastatic cutaneous squamous cell carcinoma (cSCC). Here we show in non-KS-associated patients that elevation of FERMT1 expression is increased in actinic keratoses compared to normal skin, with a further increase in cSCC supporting a pro-tumorigenic role in this population. In contrast, we show that loss of Kindlin-1 leads to increased SCC tumor growth in vivo and in 3D spheroids, which was associated with the development of a hypoxic tumor environment and increased glycolysis. The metalloproteinase Mmp13 was upregulated in Kindlin-1-depleted tumors, and increased expression of MMP13 was responsible for driving increased invasion of the Kindlin-1-depleted SCC cells. These results provide evidence that Kindlin-1 loss in SCC can promote invasion through the upregulation of MMP13, and offer novel insights into how Kindlin-1 loss leads to the development of a hypoxic environment that is permissive for tumor growth.

Yohimbine Inhibits PDGF-Induced Vascular Smooth Muscle Cell Proliferation and Migration via FOXO3a Factor

Yohimbine (YHB) has been reported to possess anti-inflammatory, anticancer, and cardiac function-enhancing properties. Additionally, it has been reported to inhibit the proliferation, migration, and neointimal formation of vascular smooth muscle cells (VSMCs) induced by platelet-derived growth factor (PDGF) stimulation by suppressing the phospholipase C-gamma 1 pathway. However, the transcriptional regulatory mechanism of YHB controlling the behavior of VSMCs is not fully understood. In this study, YHB downregulated the expression of cell cycle regulatory proteins, such as proliferating cell nuclear antigen (PCNA), cyclin D1, cyclin-dependent kinase 4 (CDK4), and cyclin E, by modulating the transcription factor FOXO3a in VSMCs induced by PDGF. Furthermore, YHB decreased p-38 and mTOR phosphorylation in a dose-dependent manner. Notably, YHB significantly reduced the phosphorylation at Y397 and Y925 sites of focal adhesion kinase (FAK), and this effect was greater at the Y925 site than Y397. In addition, the expression of paxillin, a FAK-associated protein known to bind to the Y925 site of FAK, was significantly reduced by YHB treatment in a dose-dependent manner. A pronounced reduction in the migration and proliferation of VSMCs was observed following co-treatment of YHB with mTOR or p38 inhibitors. In conclusion, this study shows that YHB inhibits the PDGF-induced proliferation and migration of VSMCs by regulating the transcription factor FOXO3a and the mTOR/p38/FAK signaling pathway. Therefore, YHB may be a potential therapeutic candidate for preventing and treating cardiovascular diseases such as atherosclerosis and vascular restenosis.

FOXO3a functions as a transcriptional and co-transcriptional splicing regulator in vascular endothelial cell lines

Recent studies have indicated a connection between Forkhead box O3a protein and coronary artery disease, yet the exact role of FOXO3a in the regulation of metabolic processes and apoptosis in vascular endothelial cells is still unknown. Therefore, we investigated the role of FOXO3a on target genes in a human vascular endothelial cell line. Through the utilization of high-throughput sequencing technology, we analyzed gene expression profiles and alternative splicing patterns in human vascular endothelial cells with FOXO3a over expression. This study identified 419 DEGs between FOXO3a-OE HUVEC model and control cells. KEGG analysis indicated that the upregulated genes were mainly enriched in inflammation-related signaling pathways, and the downregulated genes were enriched in lipid metabolism-related pathways.

Role of circadian clock system in the mitochondrial trans-sulfuration pathway and tissue remodeling

Previous studies from our laboratory revealed that the gaseous molecule hydrogen sulfide (H2S), a metabolic product of epigenetics, involves trans-sulfuration pathway for ensuring metabolism and clearance of homocysteine (Hcy) from body, thereby mitigating the skeletal muscle's pathological remodeling. Although the master circadian clock regulator that is known as brain and muscle aryl hydrocarbon receptor nuclear translocator like protein 1 (i.e., BMAL 1) is associated with S-adenosylhomocysteine hydrolase (SAHH) and Hcy metabolism but how trans-sulfuration pathway is influenced by the circadian clock remains unexplored. We hypothesize that alterations in the functioning of circadian clock during sleep and wake cycle affect skeletal muscle's biology. To test this hypothesis, we measured serum matrix metalloproteinase (MMP) activities using gelatin gels for analyzing the MMP-2 and MMP-9. Further, employing casein gels, we also studied MMP-13 that is known to be influenced by the growth arrest and DNA damage-45 (GADD45) protein during sleep and wake cycle. The wild type and cystathionine β synthase-deficient (CBS-/+) mice strains were treated with H2S and subjected to measurement of trans-sulfuration factors from skeletal muscle tissues. The results suggested highly robust activation of MMPs in the wake mice versus sleep mice, which appears somewhat akin to the "1-carbon metabolic dysregulation", which takes place during remodeling of extracellular matrix during muscular dystrophy. Interestingly, the levels of trans-sulfuration factors such as CBS, cystathionine γ lyase (CSE), methyl tetrahydrofolate reductase (MTHFR), phosphatidylethanolamine N-methyltransferase (PEMT), and Hcy-protein bound paraoxonase 1 (PON1) were attenuated in CBS-/+ mice. However, treatment with H2S mitigated the attenuation of the trans-sulfuration pathway. In addition, levels of mitochondrial peroxisome proliferator-activated receptor-gamma coactivator 1-α (PGC 1-α) and mitofusin-2 (MFN-2) were significantly improved by H2S intervention. Our findings suggest participation of the circadian clock in trans-sulfuration pathway that affects skeletal muscle remodeling and mitochondrial regeneration.

Increased Oxidative Stress and Decreased Sirtuin-3 and FOXO3 Expression Following Carotid Artery Intimal Injury in Hyperlipidemic Yucatan Microswine

Hypercholesterolemia is a major risk factor for atherosclerosis as oxidized-low-density lipoproteins (ox-LDL) contribute to the formation of foam cells and inflammation. Increased immune cell infiltration and oxidative stress induce instability of a plaque. Rupture of the unstable plaque precipitates adverse ischemic events. Since reactive oxygen species (ROS) play a critical role in plaque formation and vulnerability, regulating ROS generation may have therapeutic potential. Sirtuins, specifically sirtuin-3 (SIRT3), are antigenic molecules that can reduce oxidative stress by reducing mitochondrial ROS production through epigenetic modulation. Lack of SIRT3 expression is associated with dysregulation of ROS and endothelial function following high-fat high-cholesterol diet. SIRT3 deacetylates FOXO3a (Forkhead transcription factor O subfamily member 3a) and protects mitochondria against oxidative stress which can lead to even further protective anti-oxidizing properties. This study was designed to investigate the association between hyperlipidemia, intimal injury, chronic inflammation, and the expression of NAD-dependent deacetylase SIRT-3, FOXO3, antioxidant genes, and oxidative stress in carotid arteries of hypercholesterolemic Yucatan microswine. We found that intimal injury in hypercholesterolemic state led to increased expression of oxidative stress, inflammation, neointimal hyperplasia, and plaque size and vulnerability, while decreasing anti-oxidative regulatory genes and mediators. The findings suggest that targeting the SIRT3-FOXO3a-oxidative stress pathway will have therapeutic significance.

MiR-122 knockdown regulates vascular smooth muscle cells phenotypic switching through enhanced FOXO3 expression

Vascular smooth muscle cells (VSMCs) phenotypic switching is identified as enhanced dedifferentiation, proliferation, and migration ability of VSMCs, in which microRNAs have been identified as important regulators of the process. The present study is aimed to explore the pathophysiological effect of miR-122 on VSMC phenotypic modulation. Here, the result showed that the decreased miR-122 expression was found in VSMCs subjected to platelet-derived growth factor-BB (PDGF-BB) treatment. Next, we investigated the response of miR-122 knockdown in VSMCs with PDGF-BB stimulation. MiR-122 silencing showed increased proliferation and migration capability, whereas attenuated the differentiation markers expression. The above results were reversed by miR-122 overexpression. Finally, we further demonstrated that FOXO3 was an important target for miR-122. Collectively, we demonstrated that miR-122 silencing promoted VSMC phenotypic modulation partially through upregulated FOXO3 expression that indicated miR-122 may be a novel therapeutic target for neointimal formation.

FoxO3 normalizes Smad3-induced arterial smooth muscle cell growth

Transition of arterial smooth muscle (ASM) from a quiescent, contractile state to a growth-promoting state is a hallmark of cardiovascular disease (CVD), a leading cause of death and disability in the United States and worldwide. While many individual signals have been identified as important mechanisms in this phenotypic conversion, the combined impact of the transcription factors Smad3 and FoxO3 in ASM growth is not known. The purpose of this study was to determine that a coordinated, phosphorylation-specific relationship exists between Smad3 and FoxO3 in the control of ASM cell growth. Using a rat in vivo arterial injury model and rat primary ASM cell lysates and fractions, validated low and high serum in vitro models of respective quiescent and growth states, and adenoviral (Ad-) gene delivery for overexpression (OE) of individual and combined Smad3 and/or FoxO3, we hypothesized that FoxO3 can moderate Smad3-induced ASM cell growth. Key findings revealed unique cellular distribution of Smad3 and FoxO3 under growth conditions, with induction of both nuclear and cytosolic Smad3 yet primarily cytosolic FoxO3; Ad-Smad3 OE leading to cytosolic and nuclear expression of phosphorylated and total Smad3, with almost complete reversal of each with Ad-FoxO3 co-infection in quiescent and growth conditions; Ad-FoxO3 OE leading to enhanced cytosolic expression of phosphorylated and total FoxO3, both reduced with Ad-Smad3 co-infection in quiescent and growth conditions; Ad-FoxO3 inducing expression and activity of the ubiquitin ligase MuRF-1, which was reversed with concomitant Ad-Smad3 OE; and combined Smad3/FoxO3 OE reversing both the pro-growth impact of singular Smad3 and the cytostatic impact of singular FoxO3. A primary takeaway from these observations is the capacity of FoxO3 to reverse growth-promoting effects of Smad3 in ASM cells. Additional findings lend support for reciprocal antagonism of Smad3 on FoxO3-induced cytostasis, and these effects are dependent upon discrete phosphorylation states and cellular localization and involve MuRF-1 in the control of ASM cell growth. Lastly, results showing capacity of FoxO3 to normalize Smad3-induced ASM cell growth largely support our hypothesis, and overall findings provide evidence for utility of Smad3 and/or FoxO3 as potential therapeutic targets against abnormal ASM growth in the context of CVD.

Detection and Imaging of Active Substances in Early Atherosclerotic Lesions Using Fluorescent Probes

Atherosclerosis (AS) is a vascular disease caused by chronic inflammation and lipids that is the main cause of myocardial infarction, stroke and other cardiovascular diseases. Atherosclerosis is often difficult to detect in its early stages due to the absence of clinically significant vascular stenosis. This is not conducive to early intervention or treatment of the disease. Over the past decade, researchers have developed various imaging methods for the detection and imaging of atherosclerosis. At the same time, more and more biomarkers are being found that can be used as targets for detecting atherosclerosis. Therefore, the development of a variety of imaging methods and a variety of targeted imaging probes is an important project to achieve early assessment and treatment of atherosclerosis. This paper provides a comprehensive review of the optical probes used to detect and target atherosclerosis imaging in recent years, and describes the current challenges and future development directions.

Potential roles of endothelial cells-related non-coding RNAs in cardiovascular diseases

Endothelial dysfunction is identified by a conversion of the endothelium toward decreased vasodilation and prothrombic features and is known as a primary pathogenic incident in cardiovascular diseases. An insight based on particular and promising biomarkers of endothelial dysfunction may possess vital clinical significances. Currently, non-coding RNAs due to their participation in critical cardiovascular processes like initiation and progression have gained much attention as possible diagnostic as well as prognostic biomarkers in cardiovascular diseases. Emerging line of proof has demonstrated that abnormal expression of non-coding RNAs is nearly correlated with the pathogenesis of cardiovascular diseases. In the present review, we focus on the expression and functional effects of various kinds of non-coding RNAs in cardiovascular diseases and negotiate their possible clinical implications as diagnostic or prognostic biomarkers and curative targets.

FoxO3 and oxidative stress: a multifaceted role in cellular adaptation

Oxidative stress is a major cause of morbidity and mortality in human health and disease. In this review, we focus on the Forkhead Box (Fox) subclass O3 (FoxO3), an extensively studied transcription factor that plays a pleiotropic role in a wide range of physiological and pathological processes by regulating multiple gene regulatory networks involved in the modulation of numerous aspects of cellular metabolism, including fuel metabolism, cell death, and stress resistance. This review will also focus on regulatory mechanisms of FoxO3 expression and activity, such as crucial post-translational modifications and non-coding RNAs. Moreover, this work discusses and evidences some pathways to how this transcription factor and reactive oxygen species regulate each other, which may lead to the pathogenesis of various types of diseases. Therefore, in addition to being a promising therapeutic target, the FoxO3-regulated signaling pathways can also be used as reliable diagnostic and prognostic biomarkers and indicators for drug responsiveness.

Molecular Mechanisms in Genetic Aortopathy-Signaling Pathways and Potential Interventions

Thoracic aortic disease affects people of all ages and the majority of those aged <60 years have an underlying genetic cause. There is presently no effective medical therapy for thoracic aneurysm and surgery remains the principal intervention. Unlike abdominal aortic aneurysm, for which the inflammatory/atherosclerotic pathogenesis is well established, the mechanism of thoracic aneurysm is less understood. This paper examines the key cell signaling systems responsible for the growth and development of the aorta, homeostasis of endothelial and vascular smooth muscle cells and interactions between pathways. The evidence supporting a role for individual signaling pathways in pathogenesis of thoracic aortic aneurysm is examined and potential novel therapeutic approaches are reviewed. Several key signaling pathways, notably TGF-β, WNT, NOTCH, PI3K/AKT and ANGII contribute to growth, proliferation, cell phenotype and survival for both vascular smooth muscle and endothelial cells. There is crosstalk between pathways, and between vascular smooth muscle and endothelial cells, with both synergistic and antagonistic interactions. A common feature of the activation of each is response to injury or abnormal cell stress. Considerable experimental evidence supports a contribution of each of these pathways to aneurysm formation. Although human information is less, there is sufficient data to implicate each pathway in the pathogenesis of human thoracic aneurysm. As some pathways i.e., WNT and NOTCH, play key roles in tissue growth and organogenesis in early life, it is possible that dysregulation of these pathways results in an abnormal aortic architecture even in infancy, thereby setting the stage for aneurysm development in later life. Given the fine tuning of these signaling systems, functional polymorphisms in key signaling elements may set up a future risk of thoracic aneurysm. Multiple novel therapeutic agents have been developed, targeting cell signaling pathways, predominantly in cancer medicine. Future investigations addressing cell specific targeting, reduced toxicity and also less intense treatment effects may hold promise for effective new medical treatments of thoracic aortic aneurysm.

Transcription factors: key regulatory targets of vascular smooth muscle cell in atherosclerosis

Atherosclerosis (AS), leading to gradual occlusion of the arterial lumen, refers to the accumulation of lipids and inflammatory debris in the arterial wall. Despite therapeutic advances over past decades including intervention or surgery, atherosclerosis is still the most common cause of cardiovascular diseases and the main mechanism of death and disability worldwide. Vascular smooth muscle cells (VSMCs) play an imperative role in the occurrence of atherosclerosis and throughout the whole stages. In the past, there was a lack of comprehensive understanding of VSMCs, but the development of identification technology, including in vivo single-cell sequencing technology and lineage tracing with the CreERT2-loxP system, suggests that VSMCs have remarkable plasticity and reevaluates well-established concepts about the contribution of VSMCs. Transcription factors, a kind of protein molecule that specifically recognizes and binds DNA upstream promoter regions or distal enhancer DNA elements, play a key role in the transcription initiation of the coding genes and are necessary for RNA polymerase to bind gene promoters. In this review, we highlight that, except for environmental factors, VSMC genes are transcriptionally regulated through complex interactions of multiple conserved cis-regulatory elements and transcription factors. In addition, through a series of transcription-related regulatory processes, VSMCs could undergo phenotypic transformation, proliferation, migration, calcification and apoptosis. Finally, enhancing or inhibiting transcription factors can regulate the development of atherosclerotic lesions, and the downstream molecular mechanism of transcriptional regulation has also been widely studied.

The Pan-Cancer Multi-Omics Landscape of FOXO Family Relevant to Clinical Outcome and Drug Resistance

The forkhead box O (FOXO) transcription factors (TFs) family are frequently mutated, deleted, or amplified in various human cancers, making them attractive candidates for therapy. However, their roles in pan-cancer remain unclear. Here, we evaluated the expression, prognostic value, mutation, methylation, and clinical features of four FOXO family genes (FOXO1, FOXO3, FOXO4, and FOXO6) in 33 types of cancers based on the Cancer Genome Atlas (TCGA) and Genotype Tissue Expression (GTEx) databases. We used a single sample gene set enrichment analysis (ssGSEA) algorithm to establish a novel index called "FOXOs score". Moreover, we investigated the association between the FOXOs score and tumor microenvironment (TME), the responses to multiple treatments, along with drug resistance. We found that the FOXO family genes participated in tumor progression and were related to the prognosis in various types of cancer. We calculated the FOXOs score and found that it was significantly correlated with multiple malignant pathways in pan-cancer, including Wnt/beta-catenin signaling, TGF-beta signaling, and hedgehog signaling. In addition, the FOXOs score was also associated with multiple immune-related characteristics. Furthermore, the FOXOs score was sensitive for predicting the efficacy of diverse treatments in multiple cancers, especially immunotherapy. In conclusion, FOXO family genes were vital in pan-cancer and were strongly correlated with the TME. A high FOXOs score indicated an excellent immune-activated TME and sensitivity to multiple treatments. Hence, the FOXOs score might potentially be used as a biomarker in patients with a tumor.

Role of PCK2 in the proliferation of vascular smooth muscle cells in neointimal hyperplasia

Vascular smooth muscle cell (VSMC) proliferation is a hallmark of neointimal hyperplasia (NIH) in atherosclerosis and restenosis post-balloon angioplasty and stent insertion. Although numerous cytotoxic and cytostatic therapeutics have been developed to reduce NIH, it is improbable that a multifactorial disease can be successfully treated by focusing on a preconceived hypothesis. We, therefore, aimed to identify key molecules involved in NIH via a hypothesis-free approach. We analyzed four datasets (GSE28829, GSE43292, GSE100927, and GSE120521), evaluated differentially expressed genes (DEGs) in wire-injured femoral arteries of mice, and determined their association with VSMC proliferation in vitro. Moreover, we performed RNA sequencing on platelet-derived growth factor (PDGF)-stimulated human VSMCs (hVSMCs) post-phosphoenolpyruvate carboxykinase 2 (PCK2) knockdown and investigated pathways associated with PCK2. Finally, we assessed NIH formation in Pck2 knockout (KO) mice by wire injury and identified PCK2 expression in human femoral artery atheroma. Among six DEGs, only PCK2 and RGS1 showed identical expression patterns between wire-injured femoral arteries of mice and gene expression datasets. PDGF-induced VSMC proliferation was attenuated when hVSMCs were transfected with PCK2 siRNA. RNA sequencing of PCK2 siRNA-treated hVSMCs revealed the involvement of the Akt-FoxO-PCK2 pathway in VSMC proliferation via Akt2, Akt3, FoxO1, and FoxO3. Additionally, NIH was attenuated in the wire-injured femoral artery of Pck2-KO mice and PCK2 was expressed in human femoral atheroma. PCK2 regulates VSMC proliferation in response to vascular injury via the Akt-FoxO-PCK2 pathway. Targeting PCK2, a downstream signaling mediator of VSMC proliferation, may be a novel therapeutic approach to modulate VSMC proliferation in atherosclerosis.

Epigenetic Control of Vascular Smooth Muscle Cell Function in Atherosclerosis: A Role for DNA Methylation

Atherosclerosis is a complex vascular inflammatory disease in which multiple cell types are involved, including vascular smooth muscle cells (VSMCs). In response to vascular injury and inflammatory stimuli, VSMCs undergo a "phenotypic switching" characterized by extracellular matrix secretion, loss of contractility, and abnormal proliferation and migration, which play a key role in the progression of atherosclerosis. DNA methylation modification is an important epigenetic mechanism that plays an important role in atherosclerosis. Studies investigating abnormal DNA methylation in patients with atherosclerosis have determined a specific DNA methylation profile, and proposed multiple pathways and genes involved in the etiopathogenesis of atherosclerosis. Recent studies have also revealed that DNA methylation modification controls VSMC function by regulating gene expression involved in atherosclerosis. In this review, we summarize the recent advances regarding the epigenetic control of VSMC function by DNA methylation in atherosclerosis and provide insights into the development of VSMC-centered therapeutic strategies.

Longevity-Promoting Pathways and Transcription Factors Respond to and Control Extracellular Matrix Dynamics During Aging and Disease

Aging is one of the largest risk factors for cancer, type 2 diabetes, osteoarthritis, cardiovascular diseases, and other age-related pathologies. Here, we give a detailed description of the interplay of chronic age-related pathologies with the remodeling of the extracellular matrix during disease development and progression. Longevity-promoting signaling pathways slow or prevent age-related diseases. In particular, we focus on the mTOR signaling pathway, sirtuins, and canonical longevity-promoting transcription factors, such as FOXO, NF-κB, and Nrf2. We extend our analysis using chromatin immunoprecipitation (ChIP) sequencing and transcriptomic data and report that many established and emerging longevity-promoting transcription factors, such as CREB1, FOXO1,3, GATA1,2,3,4, HIF1A, JUN, KLF4, MYC, NFE2L2/Nrf2, RELA/NF-κB, REST, STAT3,5A, and TP53/p53, directly regulate many extracellular matrix genes and remodelers. We propose that modulation of these pathways increases lifespan and protects from age-related diseases in part due to their effects on extracellular matrix remodeling. Therefore, to successfully treat age-related diseases, it is necessary to better understand the connection between extracellular matrix components and longevity pathways.

Regulation and Function of Matrix Metalloproteinase-13 in Cancer Progression and Metastasis

Matrix metalloproteinase-13 (MMP-13) is a member of the Matrix metalloproteinases (MMPs) family of endopeptidases. MMP-13 is produced in low amounts and is well-regulated during normal physiological conditions. Its expression and secretion are, however, increased in various cancers, where it plays multiple roles in tumour progression and metastasis. As an interstitial collagenase, MMP-13 can proteolytically cleave not only collagens I, II and III, but also a range of extracellular matrix proteins (ECMs). Its action causes ECM remodelling and often leads to the release of various sequestered growth and angiogenetic factors that promote tumour cell growth, invasion and angiogenesis. This review summarizes our current understanding of the regulation of MMP-13 expression and secretion and discusses the actions of MMP-13 in cancer progression and metastasis.

Senescence in Vascular Smooth Muscle Cells and Atherosclerosis

Vascular smooth muscle cells (VSMCs) are the primary cell type involved in the atherosclerosis process; senescent VSMCs are observed in both aged vessels and atherosclerotic plaques. Factors associated with the atherosclerotic process, including oxidative stress, inflammation, and calcium-regulating factors, are closely linked to senescence in VSMCs. A number of experimental studies using traditional cellular aging markers have suggested that anti-aging biochemical agents could be used to treat atherosclerosis. However, doubt has recently been cast on such potential due to the increasingly apparent complexity of VSMCs status and an incomplete understanding of the role that these cells play in the atherosclerosis process, as well as a lack of specific or spectrum-limited cellular aging markers. The utility of anti-aging drugs in atherosclerosis treatment should be reevaluated. Promotion of a healthy lifestyle, exploring in depth the characteristics of each cell type associated with atherosclerosis, including VSMCs, and development of targeted drug delivery systems will ensure efficacy whilst evaluation of the safety and tolerability of drug use should be key aims of future anti-atherosclerosis research. This review summarizes the characteristics of VSMC senescence during the atherosclerosis process, the factors regulating this process, as well as an overview of progress toward the development and application of anti-aging drugs.

Identification of HMOX1 as a Critical Ferroptosis-Related Gene in Atherosclerosis

Ferroptosis is a novel form of programmed iron-dependent cell death. The ferroptosis-related genes (FRGs) have been recognized as biomarkers for cancers. Increasing evidence has indicated that ferroptosis is involved in the process of atherosclerosis. However, the potential FRGs used for the diagnosis, prognosis and therapy for atherosclerosis are still unclear. We aimed to identify the ferroptosis-related differentially expressed genes (DEGs) of atherosclerosis. We downloaded the mRNA-sequencing data of patients with atherosclerosis from the Gene Expression Omnibus (GEO) database. HMOX1 was identified as an essential ferroptosis-related DEG by bioinformatic analysis of the GSE28829 and GSE43292 datasets. The pro-ferroptotic effect of HMOX1 was validated through cell experiments. Then we conducted a single-gene analysis of HMOX1 and found that high-expression of HMOX1 in atherosclerotic plaques was accompanied by matrix metalloproteinases (MMPs) producing and M0 macrophages infiltration. Taken together, our present study suggested HMOX1 as a potential diagnostic biomarker for atherosclerosis and provided more evidence about the vital role of ferroptosis in atherosclerosis progression.

STAT3 induces breast cancer growth via ANGPTL4, MMP13 and STC1 secretion by cancer associated fibroblasts

In the tumor microenvironment, Cancer Associated Fibroblasts (CAFs) become activated by cancer cells and increase their secretory activity to produce soluble factors that contribute to tumor cells proliferation, invasion and dissemination to distant organs. The pro-tumorigenic transcription factor STAT3 and its canonical inducer, the pro-inflammatory cytokine IL-6, act conjunctly in a positive feedback loop that maintains high levels of IL-6 secretion and STAT3 activation in both tumor and stromal cells. Here, we demonstrate that STAT3 is essential for the pro-tumorigenic functions of murine breast cancer CAFs both in vitro and in vivo, and identify a STAT3 signature significantly enriched for genes encoding for secreted proteins. Among these, ANGPTL4, MMP13 and STC-1 were functionally validated as STAT3-dependent mediators of CAF pro-tumorigenic functions by different approaches. Both in vitro and in vivo CAFs activities were moreover impaired by MMP13 inhibition, supporting the feasibility of a therapeutic approach based on inhibiting STAT3-induced CAF-secreted proteins. The clinical potential of such an approach is supported by the observation that an equivalent CAF-STAT3 signature in humans is expressed at high levels in breast cancer stromal cells and characterizes patients with a shorter disease specific survival, including those with basal-like disease.

Chromodomain Helicase DNA Binding Protein 1-like, a negative regulator of Forkhead box O3a, promotes the proliferation and migration of Angiotensin II-induced vascular smooth muscle cells

Essential hypertension (EH) represents a major risk factor for stroke, myocardial infarction, and heart failure. Dysregulated proliferation and migration of vascular smooth muscle cells (VSMCs) play an important role in pathogenesis of EH. This study aims to investigate the effect of Chromodomain Helicase DNA Binding Protein 1-Like (CHD1L) on Angiotensin II (AngII)-induced VSMCs injury and reveal the underlying mechanism. The expression of CHD1L in EH patients was determined by bioinformatics analysis, and then it was silenced in AngII-induced VSMCs to detect the changes in cellular functions including proliferation, migration, invasion and phenotypic switching via CCK-8, EDU staining, wound healing, transwell and Western blot assays, respectively. Inflammation and oxidative stress were also measured by detecting related markers via commercial kits. After confirming the binding sites between forkhead box O3A (FOXO3a) and CHD1L and their negative association by bioinformatics analysis, FOXO3a was further silenced, and the cellular functions were assessed again to reveal the underlying mechanism. Results showed that CHD1L was highly expressed in EH, and interference of CHD1L suppressed the proliferation, migration, invasion and phenotypic switching in VSMCs. Inflammation and oxidative stress were also restrained by CHD1L knockdown. After validating the negative role of FOXO3a in regulating CHD1L, it was found that FOXO3a abrogated the effect of CHD1L knockdown on the cellular functions of AngII-induced VSMCs. In conclusion, FOXO3a suppresses the proliferation and migration of AngII-induced VSMCs by down-regulating CHD1L.

Longevity Factor FOXO3: A Key Regulator in Aging-Related Vascular Diseases

Forkhead box O3 (FOXO3) has been proposed as a homeostasis regulator, capable of integrating multiple upstream signaling pathways that are sensitive to environmental changes and counteracting their adverse effects due to external changes, such as oxidative stress, metabolic stress and growth factor deprivation. FOXO3 polymorphisms are associated with extreme human longevity. Intriguingly, longevity-associated single nucleotide polymorphisms (SNPs) in human FOXO3 correlate with lower-than-average morbidity from cardiovascular diseases in long-lived people. Emerging evidence indicates that FOXO3 plays a critical role in vascular aging. FOXO3 inactivation is implicated in several aging-related vascular diseases. In experimental studies, FOXO3-engineered human ESC-derived vascular cells improve vascular homeostasis and delay vascular aging. The purpose of this review is to explore how FOXO3 regulates vascular aging and its crucial role in aging-related vascular diseases.

Methamphetamine mediates apoptosis of vascular smooth muscle cells via the chop-related endoplasmic reticulum stress pathway

Methamphetamine (METH) is a highly addictive amphetamine-type drug that has caused persistent harm to society and human health in recent years. Most studies have shown that METH severely damages the central nervous system, and this drug has been found to be toxic to the cardiovascular system in recent years. Therefore, we hypothesized that METH may also damage vascular smooth muscle. We examined the expression of the apoptosis-related proteins Caspase 3 and PARP after METH treatment in vivo and in vitro and detected the expression of endoplasmic reticulum stress-related proteins. After treatment with the endoplasmic reticulum stress inhibitor 4-PBA, changes in the above indicators were examined. C/EBP homologous protein (Chop) expression was also detected, and the relationship between endoplasmic reticulum stress and apoptosis was further determined by siRNA silencing of Chop. The results indicated that METH can induce apoptosis of vascular smooth muscle cells (VSMCs) and upregulate the expression of Chop and endoplasmic reticulum stress-related proteins. Chop inhibits protein kinase B phosphorylation and further inhibits forkhead box class O3a (Foxo3a) dephosphorylation, resulting in increased p53 upregulated molecular of apoptosis (PUMA) transcription. Increased PUMA induces apoptosis through the mitochondrial pathway. These results indicate that Chop is involved in the METH-induced endoplasmic reticulum stress and apoptosis in VSMCs and may be a potential therapeutic target for METH-induced VSMC injury.

Research progress in apoptosis of vascular smooth muscle cells in atherosclerosis

Vascular smooth muscle cell (VSMC) is one of the main cell types in blood vessel wall, and the VSMC apoptosis is involved in the development of atherosclerosis (AS). In early AS, the apoptosis of VSMC is regarded as a compensatory mechanism for neointimal hyperplasia and lumen stenosis. However, this process will also accelerate the rupture of atherosclerotic plaques, resulting in serious cardiovascular complications. More studies on the related genes, RNA, and inducing factors of VSMCs apoptosis in occurrence and development of AS can provide scientific strategies for prevention and treatment of AS in different periods.

Urine peptidome analysis in cardiorenal syndrome reflects molecular processes

The cardiorenal syndrome (CRS) is defined as the confluence of heart-kidney dysfunction. This study investigates the molecular differences at the level of the urinary peptidome between CRS patients and controls and their association to disease pathophysiology. The urinary peptidome of CRS patients (n = 353) was matched for age and sex with controls (n = 356) at a 1:1 ratio. Changes in the CRS peptidome versus controls were identified after applying the Mann-Whitney test, followed by correction for multiple testing. Proteasix tool was applied to investigate predicted proteases involved in CRS-associated peptide generation. Overall, 559 differentially excreted urinary peptides were associated with CRS patients. Of these, 193 peptides were specifically found in CRS when comparing with heart failure and chronic kidney disease urinary peptide profiles. Proteasix predicted 18 proteases involved in > 1% of proteolytic cleavage events including multiple forms of MMPs, proprotein convertases, cathepsins and kallikrein 4. Forty-four percent of the cleavage events were produced by 3 proteases including MMP13, MMP9 and MMP2. Pathway enrichment analysis supported that ECM-related pathways, fibrosis and inflammation were represented. Collectively, our study describes the changes in urinary peptides of CRS patients and potential proteases involved in their generation, laying the basis for further validation.

Signaling pathways associated with structural changes in varicose veins: a case-control study

INTRODUCTION AND OBJECTIVES

In varicose veins, blood pressure increases in the veins of the lower extremities due to mechanical stimulation and function remodeling. The aim of this study is assessment of Signaling pathways associated with structural changes in varicose veins.

MATERIALS AND METHODS

This pilot study was performed on patients with varicose veins, which had undergone surgery. The healthy tissues from trauma patients or vascular bypass without underlying diseases were used for control samples. Hematoxylin-eosin, trichrome, and elastin staining were used for histopathological examination. The levels of MDA (malondialdehyde), total thiol, SOD (Superoxide dismutase) and NO (nitric oxide) level were measured using Elisa kits to evaluate the oxidative stress level. Gene expression levels of MMP2, MMP9, FOXO3a, APOE and p53 genes were determined using Real-time PCR.

RESULTS

This study showed, the vascular Vein wall changes are visible in vascular collagen staining. Although these changes are observed in the structure of vascular wall collagen fibers, the accumulation of collagen and elastin was increased in the walls of varicose veins compared to the control group. The amount of nitric oxide and thiol were increased in the varicose group (P < 0.0001). The expression of metalloproteinase2 gene associated with extracellular matrix change was increased in varicose veins. However, the amount of metalloproteinase 9 was decreased in this group compared to control group. FOXO3a, APOE Genes were down-regulated in the varicose veins compared to control group, while p53 gene expression was significantly increased in the varicose group (P < 0.0001).

CONCLUSION

This study demonstrated changes in oxidative stress, morphological structure, and aging pathways in varicose when compared to non-varicose veins. The changes in oxidative stress may be associated with the variations in morphological structure and aging pathways which contribute to the pathogenesis of varicose veins.

Silencing lncRNA AK136714 reduces endothelial cell damage and inhibits atherosclerosis

Atherosclerosis correlates with ischemic cardio-cerebrovascular diseases such as coronary heart disease. Long non-coding RNAs (lncRNAs) can promote atherosclerosis. We investigated the role of the lncRNA AK136714 in atherosclerosis. Compared with the healthy group, lncRNA AK136714 expression was elevated in the plaque and plasma of the atherosclerosis patients in a GEO dataset. AK136714 silencing inhibited atherosclerosis formation in ApoE-/- mice. AK136714 silencing also protected the endothelial barrier and inhibited endothelial cell inflammation. In vitro assays showed that knockdown of AK136714 suppressed the inflammatory response and apoptosis in human umbilical vein endothelial cells (HUVECs). Moreover, AK136714 was found to bind directly to HuR to increase the mRNA stability of TNF-α, IL-1β and IL-6 mRNAs. In addition, AK136714 promoted the transcription of Bim. This study expands our understanding of the role of lncRNA AK136714 in atherosclerosis and provides potential drug targets for the treatment of atherosclerosis.

Senescence-induced inflammation: an important player and key therapeutic target in atherosclerosis

Inflammation is a hallmark and potent driver of pathological vascular remodelling in atherosclerosis. However, current anti-inflammatory therapeutic strategies have shown mixed results. As an alternative perspective on the conundrum of chronic inflammation emerging evidence points towards a small subset of senescent cells as a critical player and central node driving atherosclerosis. Senescent cells belonging to various cell types are a dominant and chronic source of a large array of pro-inflammatory cytokines and various additional plaque destabilizing factors, being involved with various aspects of atherosclerosis pathogenesis. Antagonizing these key agitators of local chronic inflammation and plaque instability may provide a causative and multi-purpose therapeutic strategy to treat atherosclerosis. Anti-senescence treatment options with translational potential are currently in development. However, several questions and challenges remain to be addressed before these novel treatment approaches may enter the clinical setting.

Punicalin alleviates TNF-α- and IL-1β-induced chondrocyte dysfunction and cartilage metabolism via mediating FOXO3 signaling axis

Forkhead box O3 (FOXO3) transcription factor is involved in chondral homeostasis of normal, aging and osteoarthritis (OA) cartilage. At present, we aimed to investigate whether FOXO3 is a target of punicalin to prevent IL-1β- and TNF-α-induced chondrocyte dysfunction in vitro and in vivo models. Cell and mouse models of chondrocyte dysfunction were established to determine the pharmacological value of hydrolyzable tannin, punicalin, which was extracted from the pomegranate. FOXO3 protein levels in the nucleus and cytoplasm were analysed using western blot. Safranine O staining was performed to evaluate the expansion of growth plate and chondrocyte differentiation in IL-1β- and TNF-α-treated mice. In IL-1β- and TNF-α-treated chondrocytes and mice, IL-1β and TNF-α evoked phosphorylation and nucleocytoplasmic shuttling of FOXO3, as well as reduced FOXO3 expression levels in the nucleus. However, punicalin treatment repressed FOXO3 phosphorylation and cytoplasmic transfer. Punicalin treatment improved IL-1β and TNF-α-induced growth inhibition and apoptosis of chondrocyte and the abnormal expansion of growth plate and hypertrophic zone. Moreover, punicalin could maintain the normal phenotype of chondrocyte via mediating multiple gene expression. Punicalin showed a beneficial effect on IL-1β- and TNF-α-stimulated chondrocytes and cartilaginous metabolic disorders via preserving the transcriptional activity of FOXO3. PRACTICAL APPLICATIONS: Our study presents a prospective adjuvant therapeutic drug, punicalin, to prevent inflammation-related cartilage injury and chondrocyte dysfunction.

Loss of FoxO3a prevents aortic aneurysm formation through maintenance of VSMC homeostasis

Vascular smooth muscle cell (VSMC) phenotypic switching plays a critical role in the formation of abdominal aortic aneurysms (AAAs). FoxO3a is a key suppressor of VSMC homeostasis. We found that in human and animal AAA tissues, FoxO3a was upregulated, SM22α and α-smooth muscle actin (α-SMA) proteins were downregulated and synthetic phenotypic markers were upregulated, indicating that VSMC phenotypic switching occurred in these diseased tissues. In addition, in cultured VSMCs, significant enhancement of FoxO3a expression was found during angiotensin II (Ang II)-induced VSMC phenotypic switching. In vivo, FoxO3a overexpression in C57BL/6J mice treated with Ang II increased the formation of AAAs, whereas FoxO3a knockdown exerted an inhibitory effect on AAA formation in ApoE^−/− mice infused with Ang II. Mechanistically, FoxO3a overexpression significantly inhibited the expression of differentiated smooth muscle cell (SMC) markers, activated autophagy, the essential repressor of VSMC homeostasis, and promoted AAA formation. Our study revealed that FoxO3a promotes VSMC phenotypic switching to accelerate AAA formation through the P62/LC3BII autophagy signaling pathway and that therapeutic approaches that decrease FoxO3a expression may prevent AAA formation.

The Napkin-Ring Sign – the Story Behind Invasive Coronary Angiography

Coronary artery disease (CAD) represents one of the leading causes of morbidity and mortality across Europe. Most of the patients do not experience any warning sign before the coronary event develops, therefore screening this group of patients is essential to prevent major cardiac events. Coronary computed tomography angiography (CCTA) offers a noninvasive approach of the coronary arteries, providing information not only on the presence and severity of the coronary stenosis, but is also able to characterize the structure of the coronary wall. CCTA allows complex evaluation of the extension of CAD, and by assessing the structure of the atherosclerotic plaque, it can identify its degree of vulnerability. The napkin-ring sign (NRS) represents a ring-like attenuation of the non-calcified portion of the coronary lesion and has a high specificity (96–100%) for the identification of thin cap fibroatheroma (TCFA) or culprit lesion in acute coronary syndromes (ACS). It is also an independent predictor for ACS events and the strongest predictor for future ACS. Modern CCTA can provide submillimeter isotropic spatial resolution. Thus, CT attenuation-based tissue interpretation enables the assessment of total coronary plaque burden and individual plaque components, with a similar accuracy as intravascular ultrasoud-based investigations. This review aims to present the important role of CCTA as a potent screening tool for patients with CAD, and the current evidences in the detection and quantification of vulnerable plaques.

The Two-Faced Role of SIRT6 in Cancer

Simple Summary

Cancer therapy relies on the employment of different strategies aimed at inducing cancer cell death through different mechanisms, including DNA damage and apoptosis induction. One of the key regulators of these pathways is the epigenetic enzyme SIRT6, which has been shown to have a dichotomous function in cell fate determination and, consequently, cancer initiation and progression. In this review, we aim to summarize the current knowledge on the role of SIRT6 in cancer. We show that it can act as both tumor suppressor and promoter, even in the same cancer type, depending on the biological context. We then describe the most promising modulators of SIRT6 which, through enzyme activation or inhibition, may impair tumor growth. These molecules can also be used for the elucidation of SIRT6 function, thereby advancing the current knowledge on this crucial protein.

Abstract

Sirtuin 6 (SIRT6) is a NAD⁺-dependent nuclear deacylase and mono-ADP-ribosylase with a wide spectrum of substrates. Through its pleiotropic activities, SIRT6 modulates either directly or indirectly key processes linked to cell fate determination and oncogenesis such as DNA damage repair, metabolic homeostasis, and apoptosis. SIRT6 regulates the expression and activity of both pro-apoptotic (e.g., Bax) and anti-apoptotic factors (e.g., Bcl-2, survivin) in a context-depending manner. Mounting evidence points towards a double-faced involvement of SIRT6 in tumor onset and progression since the block or induction of apoptosis lead to opposite outcomes in cancer. Here, we discuss the features and roles of SIRT6 in the regulation of cell death and cancer, also focusing on recently discovered small molecule modulators that can be used as chemical probes to shed further light on SIRT6 cancer biology and proposed as potential new generation anticancer therapeutics.

Effect of tocotrienol on the primary progression of nonalcoholic steatohepatitis in a mouse model

Tocotrienol (T3), a vitamin E (Vit E) isoform, is known to have both biological and antioxidant effects. Although alpha-tocopherol (α-Toc), another isoform of Vit E is suggested to be a useful treatment against nonalcoholic steatohepatitis (NASH), the effect of T3 on NASH is unclear. This study aimed to comparatively evaluate the effects of T3 and α-Toc on NASH in the early stage of NASH progression, using a recently established NASH mouse model induced by a choline-deficient l-amino acid-defined high-fat diet (CDAHFD). Six-week-old male mice were divided into four groups (n = 6 per group) and fed the CDAHFD for 1 week. The first group was given no other treatment (Pre). The other three groups continued the CDAHFD plus daily oral administration of Vit E-free corn oil (Control), corn oil containing α-Toc, or corn oil containing T3 for additional 2 weeks. Neither Vit E treatment changed the histologic features of NASH, but T3 significantly reduced the mRNA expression of several genes related to inflammation and fibrosis and α-Toc did not. These results suggested that oral T3 treatment was more effective than α-Toc at suppressing hepatic inflammation and fibrosis in the early stage of NASH progression in CDAHFD model mice.

OCT4 regulated neointimal formation in injured mouse arteries by matrix metalloproteinase 2-mediated smooth muscle cells proliferation and migration

The excessive proliferation and migration of vascular smooth muscle cells (VSMCs) play vital roles in neointimal hyperplasia and vascular restenosis. In the present study, we aimed to investigate the function and mechanism of octamer-binding transcription factor 4 (OCT4, a key transcription factor for maintaining stem cells in de-differentiated state) on neointima formation in response to vascular injury. Quantitative reverse-transcription polymerase chain reaction and western blot results displayed a significant increase of OCT4 levels in injured carotid arteries. Immunohistochemistry and immunofluorescence assays confirmed that the increased OCT4 expression was primarily localized in α-SMA-positive VSMCs from neointima, and colocalized with PCNA in the nuclei of VSMCs. Adenovirus-mediated OCT4 overexpression in injured carotid arteries exacerbated intimal thickening, while OCT4 knockdown significantly inhibited intimal thickening. In-vitro experiments confirmed that the increased OCT4 expression in VMSCs could be induced by platelet-derived growth factor-BB (PDGF-BB) in a time-dependent manner. Overexpression of OCT4 greatly promoted VSMCs proliferation and migration, while OCT4 knockdown significantly retarded the PDGF-BB-induced excessive proliferation and migration of VSMCs. Bioinformatics analysis, dual-luciferase reporter assay, and chromatin immunoprecipitation assay confirmed that OCT4 could upregulate matrix metalloproteinases 2 (MMP2) expression through promoting its transcription. Moreover, knockdown of MMP2 significantly attenuated OCT4-mediated VSMCs proliferation and migration. These results indicated that OCT4 facilitated neointimal formation in response to vascular injury by MMP2-mediated VSMCs proliferation and migration, and targeting OCT4 in VSMCs might be a novel therapeutic strategy for vascular restenosis.

FOXO transcription factor family in cancer and metastasis

Forkhead box O (FOXO) transcription factors regulate diverse biological processes, affecting development, metabolism, stem cell maintenance and longevity. They have also been increasingly recognised as tumour suppressors through their ability to regulate genes essential for cell proliferation, cell death, senescence, angiogenesis, cell migration and metastasis. Mechanistically, FOXO proteins serve as key connection points to allow diverse proliferative, nutrient and stress signals to converge and integrate with distinct gene networks to control cell fate, metabolism and cancer development. In consequence, deregulation of FOXO expression and function can promote genetic disorders, metabolic diseases, deregulated ageing and cancer. Metastasis is the process by which cancer cells spread from the primary tumour often via the bloodstream or the lymphatic system and is the major cause of cancer death. The regulation and deregulation of FOXO transcription factors occur predominantly at the post-transcriptional and post-translational levels mediated by regulatory non-coding RNAs, their interactions with other protein partners and co-factors and a combination of post-translational modifications (PTMs), including phosphorylation, acetylation, methylation and ubiquitination. This review discusses the role and regulation of FOXO proteins in tumour initiation and progression, with a particular emphasis on cancer metastasis. An understanding of how signalling networks integrate with the FOXO transcription factors to modulate their developmental, metabolic and tumour-suppressive functions in normal tissues and in cancer will offer a new perspective on tumorigenesis and metastasis, and open up therapeutic opportunities for malignant diseases.

Transglutaminase-2 regulates Wnt and FoxO3a signaling to determine the severity of osteoarthritis

Transglutaminase 2 (TG2), also known as tissue transglutaminase, is a calcium-dependent enzyme that has a variety of intracellular and extracellular substrates. TG2 not only increases in osteoarthritis (OA) tissue but also affects the progression of OA. However, it is still unclear how TG2 affects cartilage degradation in OA at the molecular level. Surgically induced OA lead to an increase of TG2 in the articular cartilage and growth plate, and it was dependent on TGFβ1 in primary chondrocytes. The inhibition of TG2 enzymatic activity with intra-articular injection of ZDON, the peptide-based specific TG2 inhibitor, ameliorated the severity of surgically induced OA as well as the expression of MMP-3 and MMP-13. ZDON attenuated MMP-3 and MMP-13 expression in TGFβ- and calcium ionophore-treated chondrocytes in a Runx2-independent manner. TG2 inhibition with ZDON suppressed canonical Wnt signaling through a reduction of β-catenin, which was mediated by ubiquitination-dependent proteasomal degradation. In addition, TG2 activation by a calcium ionophore enhanced the phosphorylation of AMPK and FoxO3a and the nuclear translocation of FoxO3a, which was responsible for the increase in MMP-13. In conclusion, TG2 plays an important role in the pathogenesis of OA as a major catabolic mediator that affects the stability of β-catenin and FoxO3a-mediated MMP-13 production.

17β-Estradiol Prevents Extracellular Matrix Degradation by Downregulating MMP3 Expression via PI3K/Akt/FOXO3 Pathway

STUDY DESIGN

In vitro studies of the role of 17β-estradiol (E2) and its possible targets in intervertebral disc degeneration (IDD).

OBJECTIVE

To define the regulatory role of E2 in IDD and the potential mechanisms.

SUMMARY OF BACKGROUND DATA

IDD has intricate etiology that is influenced by multiple risk factors. However, the underlying molecular mechanisms of occurrence and progression of IDD are not well elucidated. The degradation of extracellular matrix (ECM) has been extensively observed in IDD. E2 was found to inhibit ECM degradation in human nuleus pulposus cells (HNPCs), but the molecular mechanism remained to be determined.

METHODS

Western blot and qPCR was performed to quantify the expression of target proteins in HNPCs. Luciferase reporter gene assay was applied to detect the effects of E2 and forkhead box O-3 (FOXO3) on matrix metalloproteinases (MMP)-3 promoter activity. Chromatin immunoprecipitation assay analyzed the binding of FOXO3 to MMP-3 and the effect of E2 on this process.

RESULTS

We identified the upregulation of collagen II and aggrecan by E2 independent of time and concentration. And E2 downregulated MMP-3 expression in human nucleus pulposus cells. The phosphorylation of FOXO3 led to the reduction of MMP-3 promoter activity. Furthermore, 17β-estradiol-induced the activation of PI3K/Akt pathway is required for FOXO3 phosphorylated.

CONCLUSION

E2 prevents the degradation of ECM by upregulating collagen II and aggrecan expression via reducing MMP-3 expression in HNPCs, and PI3K/Akt/FOXO3 pathway is dispensable for MMP-3 downregulated. Therefore, E2 protects against IDD by preventing ECM degradation.

LEVEL OF EVIDENCE

3.

Increased hydrostatic pressure induces nuclear translocation of DAF-16/FOXO in C. elegans

Mechanical stimulation is well known to be important for maintaining tissue and organ homeostasis. Here, we found that hydrostatic pressure induced nuclear translocation of a forkhead box O (FOXO) transcription factor DAF-16, in C. elegans within minutes, whereas the removal of this pressure resulted in immediate export of DAF-16 to the cytoplasm. We also monitored DAF-16-dependent transcriptional changes by exposure to 1 MPa pressure for 5 min, and found significant changes in collagen and other genes in a DAF-16 dependent manner. Lifespan was markedly prolonged with exposure to cyclic pressure treatment (1 MPa once a day for 5 min from L1 larvae until death). Furthermore, age-dependent decline in locomotor activity was suppressed by the treatment. In contrast, the nuclear translocation of the yes-associated protein YAP-1 was not induced under the same pressure conditions. Thus, moderate hydrostatic pressure improves ageing progression through activation of DAF-16/FOXO in C. elegans.

Vascular smooth muscle cells in atherosclerosis

Vascular smooth muscle cells (VSMCs) are a major cell type present at all stages of an atherosclerotic plaque. According to the 'response to injury' and 'vulnerable plaque' hypotheses, contractile VSMCs recruited from the media undergo phenotypic conversion to proliferative synthetic cells that generate extracellular matrix to form the fibrous cap and hence stabilize plaques. However, lineage-tracing studies have highlighted flaws in the interpretation of former studies, revealing that these studies had underestimated both the content and functions of VSMCs in plaques and have thus challenged our view on the role of VSMCs in atherosclerosis. VSMCs are more plastic than previously recognized and can adopt alternative phenotypes, including phenotypes resembling foam cells, macrophages, mesenchymal stem cells and osteochondrogenic cells, which could contribute both positively and negatively to disease progression. In this Review, we present the evidence for VSMC plasticity and summarize the roles of VSMCs and VSMC-derived cells in atherosclerotic plaque development and progression. Correct attribution and spatiotemporal resolution of clinically beneficial and detrimental processes will underpin the success of any therapeutic intervention aimed at VSMCs and their derivatives.

Integrated Analysis of miRNA-mRNA Interaction Network in Porcine Granulosa Cells Undergoing Oxidative Stress

Oxidative stress (OS), a common intracellular phenomenon induced by excess reactive oxygen species (ROS) generation, has been shown to be associated with mammalian ovarian follicular development blockage and granulosa cell (GC) impairment. However, the mechanism involved in these effects remains unknown, and the effect of OS on the transcriptome profiles in porcine GCs has not been fully characterized. In this study, we found that hydrogen peroxide-mediated oxidative stress induced porcine GC apoptosis and impaired cell viability. Moreover, RNA-seq analysis showed that oxidative stress induced dramatic changes in gene expression in porcine GCs. A total of 2025 differentially expressed genes (DEGs) were identified, including 1940 DEmRNAs and 55 DEmiRNAs. Functional annotation showed that the DEGs were mainly associated with cell states and function regulation. In addition, multiple hub genes (FOXO1, SOD2, BMP2, DICER1, BCL2L11, FZD4, ssc-miR-424, and ssc-miR-27b) were identified by constructing protein-protein interaction and DEmiRNA-DEmRNA regulatory networks. Furthermore, a gene-pathway-function coregulatory network was established and demonstrated that these hub genes were enriched in FoxO, TGF-β, Wnt, PIK3-Akt, MAPK, and cAMP signaling pathways, which play important roles in regulating cell apoptosis, cell proliferation, stress responses, and hormone secretion. The current research provides a comprehensive perspective of the effects of oxidative stress on porcine GCs and also identifies potential therapeutic targets for oxidative stress-induced female infertility.

Methodological Approach for the Evaluation of FOXO as a Positive Regulator of Antioxidant Genes

All four FOXO isoforms have been shown to respond to changes in the cellular redox status of the cell, and regulate the expression of target genes that in turn can modulate the cellular oxidative status. However, the mechanisms involved are still controversial. It is clear though that redox regulation of FOXO factors occurs at different levels. The proteins themselves are redox-sensitive and their capacity to bind their target sites seems to be at least partially dependent on their oxidative status. Importantly, several of the cofactors that are known to regulate FOXO transcriptional activity are also sensitive to changes in the cellular redox status, in particular the deacetylase SirT1 is activated in response to reduced levels of reducing equivalents (increased NAD⁺/NADH⁺ ratio) and the coactivator PGC-1α is induced in response to increased cellular oxidative stress. Furthermore, nuclear localization of FOXO factors is also regulated by proteins that, like AKT, are themselves regulated directly or indirectly by the cellular levels of reactive oxygen and nitrogen species. In this technical review, we aim to update the current status of our knowledge of how to handle redox-regulated FOXO factor research in order to better understand FOXO biology.