Profilin-1 is expressed in human atherosclerotic plaques and induces atherogenic effects on vascular smooth muscle cells

Current targeting strategies and advanced nanoplatforms for atherosclerosis therapy

Atherosclerosis is one of the major causes of death worldwide, and it is closely related to many cardiovascular diseases, such as stroke, myocardial infraction and angina. Although traditional surgical and pharmacological interventions can effectively retard or slow down the progression of atherosclerosis, it is very difficult to prevent or even reverse this disease. In recent years, with the rapid development of nanotechnology, various nanoagents have been designed and applied to different diseases including atherosclerosis. The unique atherosclerotic microenvironment with signature biological components allows nanoplatforms to distinguish atherosclerotic lesions from normal tissue and to approach plaques specifically. Based on the process of atherosclerotic plaque formation, this review summarises the nanodrug delivery strategies for atherosclerotic therapy, trying to provide help for researchers to understand the existing atherosclerosis management approaches as well as challenges and to reasonably design anti-atherosclerotic nanoplatforms.

Unveiling Actin Cytoskeleton Role in Mediating Chikungunya-Associated Arthritis: An Integrative Proteome-Metabolome Study

Background: Chikungunya is a zoonotic disease caused by the Chikungunya virus (CHIKV), primarily transmitted to humans through infected Aedes mosquitoes. The infection is characterized by symptoms such as high fever, musculoskeletal pain, polyarthritis, and a rash, which can lead to severe complications such as encephalitis, meningitis, and even fatalities. While many disease manifestations resemble those of other viral infections, chronic arthritis caused by CHIKV is unique, and its molecular mechanisms remain ill-defined. Materials and Methods: Proteomics data from both cellular and patient levels of CHIKV infection were curated from PubMed and screened using inclusion and exclusion criteria. Patient serum proteomics data obtained from P RIDE underwent reanalysis using Proteome Discoverer 2.2. Enrichment and protein-protein interaction network analysis were conducted on differentially expressed proteins from both serum and cellular datasets. Metabolite data from CHIKV-infected patients were further retrieved, and their protein binding partners were identified using BindingDB. The protein-metabolite interaction pathway was further developed using MetaboAnalyst. Results: The proteomics data analysis revealed differential expression of proteins involved in critical host mechanisms, such as cholesterol metabolism and mRNA splicing, during CHIKV infection. Consistent upregulation of two actin cytoskeleton proteins, TAGLN2 and PFN1, was noted in both serum and cellular datasets, and their upregulations are associated with arthritis. Furthermore, alterations in purine metabolism were observed in the integrative proteome-metabolome analysis, correlating with cytoskeletal remodelling. Conclusion: Collectively, this integrative view sheds light on the involvement of actin cytoskeleton remodeling proteins and purine metabolic pathways in the development of arthritis during CHIKV infection.

Haplo-insufficiency of Profilin1 in vascular endothelial cells is beneficial but not sufficient to confer protection against experimentally induced atherosclerosis

Actin cytoskeleton plays an important role in various aspects of atherosclerosis, a key driver of ischemic heart disease. Actin-binding protein Profilin1 (Pfn1) is overexpressed in atherosclerotic plaques in human disease, and Pfn1, when partially depleted globally in all cell types, confers atheroprotection in vivo. This study investigates the impact of endothelial cell (EC)-specific partial loss of Pfn1 expression in atherosclerosis development. We utilized mice engineered for conditional heterozygous knockout of the Pfn1 gene in ECs, with atherosclerosis induced by depletion of hepatic LDL receptor by gene delivery of PCSK9 combined with high-cholesterol diet. Our studies show that partial depletion of EC Pfn1 has certain beneficial effects marked by dampening of select pro-atherogenic cytokines (CXCL10 and IL7) with concomitant reduction in cytotoxic T cell abundance but is not sufficient to reduce hyperlipidemia and confer atheroprotection in vivo. In light of these findings, we conclude that atheroprotective phenotype conferred by global Pfn1 haplo-insufficiency requires contributions of additional cell types that are relevant for atherosclerosis progression.

Haplo-insufficiency of Profilin1 in vascular endothelial cells is beneficial but not sufficient to confer protection against experimentally induced atherosclerosis

Actin cytoskeleton plays an important role in various aspects of atherosclerosis, a key driver of ischemic heart disease. Actin-binding protein Profilin1 (Pfn1) is overexpressed in atherosclerotic plaques in human disease, and Pfn1, when partially depleted globally in all cell types, confers atheroprotection in vivo . This study investigates the impact of endothelial cell (EC)-specific partial loss of Pfn1 expression in atherosclerosis development. We utilized mice engineered for conditional heterozygous knockout of the Pfn1 gene in ECs, with atherosclerosis induced by depletion of hepatic LDL receptor by gene delivery of PCSK9 combined with high-cholesterol diet. Our studies show that partial depletion of EC Pfn1 has certain beneficial effects marked by dampening of select pro-atherogenic cytokines (CXCL10 and IL7) with concomitant reduction in cytotoxic T cell abundance but is not sufficient to reduce hyperlipidemia and confer atheroprotection in vivo . In light of these findings, we conclude that atheroprotective phenotype conferred by global Pfn1 haplo-insufficiency requires contributions of additional cell types that are relevant for atherosclerosis progression.

Vascular endothelial cell-specific disruption of the profilin1 gene leads to severe multiorgan pathology and inflammation causing mortality

Actin-binding protein Profilin1 is an important regulator of actin cytoskeletal dynamics in cells and critical for embryonic development in higher eukaryotes. The objective of the present study was to examine the consequence of loss-of-function of Pfn1 in vascular endothelial cells (ECs) in vivo. We utilized a mouse model engineered for tamoxifen-inducible biallelic inactivation of the Pfn1 gene selectively in EC (Pfn1EC-KO). Widespread deletion of EC Pfn1 in adult mice leads to severe health complications presenting overt pathologies (endothelial cell death, infarct, and fibrosis) in major organ systems and evidence for inflammatory infiltrates, ultimately compromising the survival of animals within 3 weeks of gene ablation. Mice deficient in endothelial Pfn1 exhibit selective bias toward the proinflammatory myeloid-derived population of immune cells, a finding further supported by systemic elevation of proinflammatory cytokines. We further show that triggering Pfn1 depletion not only directly upregulates proinflammatory cytokine/chemokine gene expression in EC but also potentiates the paracrine effect of EC on proinflammatory gene expression in macrophages. Consistent with these findings, we provide further evidence for increased activation of Interferon Regulatory Factor 7 (IRF7) and STAT1 in EC when depleted of Pfn1. Collectively, these findings for the first time demonstrate a prominent immunological consequence of loss of endothelial Pfn1 and an indispensable role of endothelial Pfn1 in mammalian survival unlike tolerable phenotypes of Pfn1 loss in other differentiated cell types.

Rosuvastatin effects on the HDL proteome in hyperlipidemic patients

The advancements in proteomics have provided a better understanding of the functionality of apolipoproteins and lipoprotein-associated proteins, with the HDL lipoprotein fraction being the most studied. The focus of this study was to evaluate the HDL proteome in dyslipidemic subjects without an established cardiovascular disease, as well as to test whether rosuvastatin treatment alters the HDL proteome. Patients with primary hypercholesterolemia or mixed dyslipidemia were assigned to 20 mg/day rosuvastatin and blood samples were drawn at study entry and after 12 weeks of treatment. A label-free LC-MS/MS protein profiling was conducted, coupled with bioinformatics analysis. Sixty-nine HDL proteins were identified, belonging to four main biological function clusters: lipid transport and metabolism; platelet activation, degranulation, and aggregation, wound response and wound healing; immune response; inflammatory and acute phase response. Five HDL proteins showed statistically significant differences in the abundance (Anova ≤ 0.05), before and after rosuvastatin treatment. Platelet factor 4 variant (PF4V1), Pregnancy-specific beta-1-glycoprotein 2 (PSG2), Profilin-1 (PFN1) and Keratin type II cytoskeletal 2 epidermal (KRT2) showed decreased expressions, while Integrin alpha-IIb (ITGA2B) showed an increased expression after treatment with rosuvastatin. The ELISA validation of PFN1 segregated the subjects into responders and non-responders, as PFN1 levels after rosuvastatin were shown to mostly depend on the subjects' inflammatory phenotype. Findings from this study introduce novel insights into the HDL proteome and statin pleiotropism.

Serum proteomic identification and validation of two novel atherosclerotic aortic aneurysm biomarkers, profilin 1 and complement factor D

BACKGROUND

Effective diagnostic biomarkers for aortic aneurysm (AA) that are detectable in blood tests are required because early detection and rupture risk assessment of AA can provide insights into medical therapy and preventive treatments. However, known biomarkers for AA lack specificity and reliability for clinical diagnosis.

METHODS

We performed proteome analysis of serum samples from patients with atherosclerotic thoracic AA (TAA) and healthy control (HC) subjects to identify diagnostic biomarkers for AA. Serum samples were separated into low-density lipoprotein, high-density lipoprotein, and protein fractions, and the major proteins were depleted. From the proteins identified in the three fractions, we narrowed down biomarker candidates to proteins uniformly altered in all fractions between patients with TAA and HC subjects and evaluated their capability to discriminate patients with TAA and those with abdominal AA (AAA) from HC subjects using receiver operating characteristic (ROC) analysis. For the clinical validation, serum concentrations of biomarker candidates were measured in patients with TAA and AAA registered in the biobank of the same institute, and their capability for the diagnosis was evaluated.

RESULTS

Profilin 1 (PFN1) and complement factor D (CFD) showed the most contrasting profiles in all three fractions between patients with TAA and HC subjects and were selected as biomarker candidates. The PFN1 concentration decreased, whereas the CFD concentration increased in the sera of patients with TAA and AAA when compared with those of HC subjects. The ROC analysis showed that these proteins could discriminate patients with TAA and AAA from HC subjects. In the validation study, these candidates showed significant concentration differences between patients with TAA or AAA and controls. PFN1 and CFD showed sufficient area under the curve (AUC) in the ROC analysis, and their combination further increased the AUC. The serum concentrations of PFN1 and CFD also showed significant differences between patients with aortic dissection and controls in the validation study.

CONCLUSION

PFN1 and CFD are potential diagnostic biomarkers for TAA and AAA and measurable in blood samples; their diagnostic performance can be augmented by their combination. These biomarkers may facilitate the development of diagnostic systems to identify patients with AA.

Molecularly targeted nanomedicine enabled by inorganic nanoparticles for atherosclerosis diagnosis and treatment

Atherosclerosis, a chronic cardiovascular disease caused by plaque development in arteries, remains a leading cause of morbidity and mortality. Atherosclerotic plaques are characterized by the expression and regulation of key molecules such as cell surface receptors, cytokines, and signaling pathway proteins, potentially facilitating precise diagnosis and treatment on a molecular level by specifically targeting the characteristic molecules. In this review, we highlight the recent progress in the past five years on developing molecularly targeted nanomedicine for imaging detection and treatment of atherosclerosis with the use of inorganic nanoparticles. Through targeted delivery of imaging contrast nanoparticles to specific molecules in atherogenesis, atherosclerotic plaque development at different stages could be identified and monitored via various molecular imaging modalities. We also review molecularly targeted therapeutic approaches that target and regulate molecules associated with lipid regulation, inflammation, and apoptosis. The review is concluded with discussion on current challenges and future development of nanomedicine for atherosclerotic diagnosis and treatment.

Profilin-1 prevents psoriasis pathogenesis through IκBζ regulation

Profilin-1 (PFN-1) is an actin-binding protein that regulates actin polymerization, cell proliferation, apoptosis, angiogenesis, and carcinogenesis. Its dysregulation has been reported in diverse pathologic diseases; however, the role of PFN-1 in psoriasis has not yet been elucidated. In this study, we demonstrate that PFN-1 expression is increased in both skin and serum of patients with psoriasis. PFN-1 was markedly expressed in the epidermis of psoriatic lesions and its expression positively correlated with psoriasis severity. IL-17A treatment of keratinocytes increased the PFN-1 expression, whereas TNF-α induced the PFN-1 expression and secretion. In addition, knockdown of PFN-1 with shRNA resulted in an altered expression of psoriasis-associated inflammatory markers, HBD-2, S100A7, S100A9, and Ki67, and recombinant PFN-1 suppressed the IL-17A-induced inflammatory response in keratinocytes. Interestingly, recombinant PFN-1 also suppressed IL-17A-induced IκBζ, an important player in immune response in psoriasis. Collectively, our results show that PFN-1 acts as a negative regulator of psoriatic inflammation through suppression of IκBζ, and the balanced level of PFN-1 is important for the IκBζ regulation. Thus, the expression of PFN-1 can be used as a biomarker for psoriasis severity, and it can be considered as a possible target for the treatment of psoriasis.

The role of profilin-1 in cardiovascular diseases

Dynamic remodeling of the actin cytoskeleton is an essential feature for virtually all actin-dependent cellular processes, including cell migration, cell cycle progression, chromatin remodeling and gene expression, and even the DNA damage response. An altered actin cytoskeleton is a structural hallmark associated with numerous pathologies ranging from cardiovascular diseases to immune disorders, neurological diseases and cancer. The actin cytoskeleton in cells is regulated through the orchestrated actions of a myriad of actin-binding proteins. In this Review, we provide a brief overview of the structure and functions of the actin-monomer-binding protein profilin-1 (Pfn1) and then discuss how dysregulated expression of Pfn1 contributes to diseases associated with the cardiovascular system.

Profilin 1 and Mitochondria-Partners in the Pathogenesis of Coronary Artery Disease?

Atherosclerosis remains a large health and economic burden. Even though it has been studied for more than a century, its complex pathophysiology has not been elucidated. The relatively well-established contributors include: chronic inflammation in response to oxidized cholesterol, reactive oxygen species-induced damage and apoptosis. Recently, profilin 1, a regulator of actin dynamics emerged as a potential new player in the field. Profilin is abundant in stable atherosclerotic plaques and in thrombi extracted from infarct-related arteries in patients with acute myocardial infarction. The exact role of profilin in atherosclerosis and its complications, as well as its mechanisms of action, remain unknown. Here, we summarize several pathways in which profilin may act through mitochondria in a number of processes implicated in atherosclerosis.

Actin-binding protein profilin1 promotes aggressiveness of clear-cell renal cell carcinoma cells

Clear-cell renal cell carcinoma (ccRCC), the most common subtype of renal cancer, has a poor clinical outcome. A hallmark of ccRCC is genetic loss-of-function of VHL (von Hippel-Lindau) that leads to a highly vascularized tumor microenvironment. Although many ccRCC patients initially respond to antiangiogenic therapies, virtually all develop progressive, drug-refractory disease. Given the role of dysregulated expressions of cytoskeletal and cytoskeleton-regulatory proteins in tumor progression, we performed analyses of The Cancer Genome Atlas (TCGA) transcriptome data for different classes of actin-binding proteins to demonstrate that increased mRNA expression of profilin1 (Pfn1), Arp3, cofilin1, Ena/VASP, and CapZ, is an indicator of poor prognosis in ccRCC. Focusing further on Pfn1, we performed immunohistochemistry-based classification of Pfn1 staining in tissue microarrays, which indicated Pfn1 positivity in both tumor and stromal cells; however, the vast majority of ccRCC tumors tend to be Pfn1-positive selectively in stromal cells only. This finding is further supported by evidence for dramatic transcriptional up-regulation of Pfn1 in tumor-associated vascular endothelial cells in the clinical specimens of ccRCC. In vitro studies support the importance of Pfn1 in proliferation and migration of RCC cells and in soluble Pfn1's involvement in vascular endothelial cell tumor cell cross-talk. Furthermore, proof-of-concept studies demonstrate that treatment with a novel computationally designed Pfn1-actin interaction inhibitor identified herein reduces proliferation and migration of RCC cells in vitro and RCC tumor growth in vivo Based on these findings, we propose a potentiating role for Pfn1 in promoting tumor cell aggressiveness in the setting of ccRCC.

Profilin-1 is dysregulated in endometroid (type I) endometrial cancer promoting cell proliferation and inhibiting pro-inflammatory cytokine production

Endometrial cancer (EC) is the most common gynaecological malignancy. Alarmingly its incidence and mortality rate is increasing particularly in younger women of reproductive age. Despite this, there are limited treatment options for EC. Profilin-1 (PFN1) regulates tumorigenesis in numerous cancers, but the role of PFN1 in EC has not been investigated. We hypothesized that PFN1 would have altered expression in EC and contribute to the development of EC. We quantified PFN1 in type 1 EC and benign/normal endometrium by RT-qPCR and IHC. The effect of silencing PFN1 on cell adhesion and proliferation was investigated using 2 EC cell lines (HEC1A and AN3CA). The effect of recombinant PFN1 (100 μM) on pro-inflammatory cytokine gene expression was investigated using THP1 monocyte cell line. PFN1 immunolocalized to glandular epithelial cells, vascular endothelial cells and leukocytes in the stromal compartment of normal endometrium and EC. PFN1 immunostaining intensity was significantly elevated in grade (G)I EC compared to normal endometrium, GI-II and GIII EC. In endometrial epithelial cancer cells alone, PFN1 immunostaining intensity was significantly reduced in GII and III EC compared to normal endometrium and GI EC. The stromal compartment of EC had strong PFN1 expression compared to benign and normal endometrium. Silencing PFN1 in the AN3CA endometrial epithelial cancer cell line significantly enhanced cell adhesion and proliferation. PFN1 treatment significantly down-regulated TNFα and IL1β mRNA expression by THP1 cells. This study demonstrated that whilst PFN1 production is retained in the stromal compartment of EC, PFN1 production is lost in endometrial epithelial cancer cells with increasing cancer grade. PFN1 may play a role in the tumorigenesis of EC. Loss of PFN1 in GII and GIII endometrial epithelial cancer cells associated with sustained PFN1 by infiltrating immune cells may promote EC tumorigenesis due to increased endometrial epithelial cancer cell proliferation coupled with a pro-tolerance tumor microenvironment.

Profilin choreographs actin and microtubules in cells and cancer

Actin and microtubules play essential roles in aberrant cell processes that define and converge in cancer including: signaling, morphology, motility, and division. Actin and microtubules do not directly interact, however shared regulators coordinate these polymers. While many of the individual proteins important for regulating and choreographing actin and microtubule behaviors have been identified, the way these molecules collaborate or fail in normal or disease contexts is not fully understood. Decades of research focus on Profilin as a signaling molecule, lipid-binding protein, and canonical regulator of actin assembly. Recent reports demonstrate that Profilin also regulates microtubule dynamics and polymerization. Thus, Profilin can coordinate both actin and microtubule polymer systems. Here we reconsider the biochemical and cellular roles for Profilin with a focus on the essential cytoskeletal-based cell processes that go awry in cancer. We also explore how the use of model organisms has helped to elucidate mechanisms that underlie the regulatory essence of Profilin in vivo and in the context of disease.

Profilin: many facets of a small protein

Profilin is a ubiquitously expressed protein well known as a key regulator of actin polymerisation. The actin cytoskeleton is involved in almost all cellular processes including motility, endocytosis, metabolism, signal transduction and gene transcription. Hence, profilin's role in the cell goes beyond its direct and essential function in regulating actin dynamics. This review will focus on the interactions of Profilin 1 and its ligands at the plasma membrane, in the cytoplasm and the nucleus of the cells and the regulation of profilin activity within those cell compartments. We will discuss the interactions of profilin in cell signalling pathways and highlight the importance of the cell context in the multiple functions that this small essential protein has in conjunction with its role in cytoskeletal organisation and dynamics. We will review some of the mechanisms that control profilin expression and the implications of changed expression of profilin in the light of cancer biology and other pathologies.

Disruption of profilin1 function suppresses developmental and pathological retinal neovascularization

Angiogenesis-mediated neovascularization in the eye is usually associated with visual complications. Pathological angiogenesis is particularly prominent in the retina in the settings of proliferative diabetic retinopathy, in which it can lead to permanent loss of vision. In this study, by bioinformatics analyses, we provide evidence for elevated expression of actin-binding protein PFN1 (profilin1) in the retinal vascular endothelial cells (VECs) of individuals with proliferative diabetic retinopathy, findings further supported by gene expression analyses for PFN1 in experimentally induced abnormal retinal neovascularization in an oxygen-induced retinopathy murine model. We observed that in a conditional knockout mouse model, postnatal deletion of the Pfn1 gene in VECs leads to defects in tip cell activity (marked by impaired filopodial protrusions) and reduced vascular sprouting, resulting in hypovascularization during developmental angiogenesis in the retina. Consistent with these findings, an investigative small molecule compound targeting the PFN1-actin interaction reduced random motility, proliferation, and cord morphogenesis of retinal VECs in vitro and experimentally induced abnormal retinal neovascularization in vivo In summary, these findings provide the first direct in vivo evidence that PFN1 is required for formation of actin-based protrusive structures and developmental angiogenesis in the retina. The proof of concept of susceptibility of abnormal angiogenesis to small molecule intervention of PFN1-actin interaction reported here lays a conceptual foundation for targeting PFN1 as a possible strategy in angiogenesis-dependent retinal diseases.

Construction of dual nanomedicines for the imaging and alleviation of atherosclerosis

Magnetic resonance imaging (MRI) is an essential tool for the diagnosis of atherosclerosis, a chronic cardiovascular disease. MRI primarily uses superparamagnetic iron oxide (SPIO) as a contrast agent. However, SPIO integrated with therapeutic drugs has rarely been studied. In this study, we explored biocompatible paramagnetic iron-oxide nanoparticles (NPs) in a complex with low pH-sensitive cyclodextrin for the diagnostic imaging and treatment of atherosclerosis. The NPs were conjugated with profilin-1 antibody (PFN1) to specifically target vascular smooth muscle cells (VSMCs) in the atherosclerotic plaque and integrated with the anti-inflammatory drug, rapamycin. The PFN1-CD-MNPs were easily binded to the VSMCs, indicating their good biocompatibility and low renal toxicity over the long term. Ex vivo near-infrared fluorescence (NIRF) imaging and in vivo MRI indicated the accumulation of PFN1-CD-MNPs in the atherosclerotic plaque. The RAP@PFN1-CD-MNPs alleviated the progression of arteriosclerosis. Thus, PFN1-CD-MNPs served not only as multifunctional imaging probes but also as nanovehicles for the treatment of atherosclerosis.

Endometrial profilin 1: a key player in embryo-endometrial crosstalk

Objective

Despite extensive research on implantation failure, little is known about the molecular mechanisms underlying the crosstalk between the embryo and the maternal endometrium, which is critical for successful pregnancy. Profilin 1 (PFN1), which is expressed both in the embryo and in the endometrial epithelium, acts as a potent regulator of actin polymerization and the cytoskeletal network. In this study, we identified the specific role of endometrial PFN1 during embryo implantation.

Methods

Morphological alterations depending on the status of PFN1 expression were assessed in PFN1-depleted or control cells grown on Matrigel-coated cover glass. Day-5 mouse embryos were cocultured with Ishikawa cells. Comparisons of the rates of F-actin formation and embryo attachment were performed by measuring the stability of the attached embryo onto PFN1-depleted or control cells.

Results

Depletion of PFN1 in endometrial epithelial cells induced a significant reduction in cell-cell adhesion displaying less formation of colonies and a more circular cell shape. Mouse embryos co-cultured with PFN1-depleted cells failed to form actin cytoskeletal networks, whereas more F-actin formation in the direction of surrounding PFN1-intact endometrial epithelial cells was detected. Furthermore, significantly lower embryo attachment stability was observed in PFN1-depleted cells than in control cells. This may have been due to reduced endometrial receptivity caused by impaired actin cytoskeletal networks associated with PFN1 deficiency.

Conclusion

These observations definitively demonstrate an important role of PFN1 in mediating cell-cell adhesion during the initial stage of embryo implantation and suggest a potential therapeutic target or novel biomarker for patients suffering from implantation failure.

Small Dimension-Big Impact! Nanoparticle-Enhanced Non-Invasive and Intravascular Molecular Imaging of Atherosclerosis In Vivo

Extensive translational research has provided considerable progress regarding the understanding of atherosclerosis pathophysiology over the last decades. In contrast, implementation of molecular in vivo imaging remains highly limited. In that context, nanoparticles represent a useful tool. Their variable shape and composition assure biocompatibility and stability within the environment of intended use, while the possibility of conjugating different ligands as well as contrast dyes enable targeting of moieties of interest on a molecular level and visualization throughout various imaging modalities. These characteristics have been exploited by a number of preclinical research approaches aimed at advancing understanding of vascular atherosclerotic disease, in order to improve identification of high-risk lesions prior to oftentimes fatal thromboembolic events. Furthermore, the combination of these targeted nanoparticles with therapeutic agents offers the potential of site-targeted drug delivery with minimized systemic secondary effects. This review gives an overview of different groups of targeted nanoparticles, designed for in vivo molecular imaging of atherosclerosis as well as an outlook on potential combined diagnostic and therapeutic applications.

Long noncoding RNA NEXN-AS1 mitigates atherosclerosis by regulating the actin-binding protein NEXN

Noncoding RNAs are emerging as important players in gene regulation and disease pathogeneses. Here, we show that a previously uncharacterized long noncoding RNA, nexilin F-actin binding protein antisense RNA 1 (NEXN-AS1), modulates the expression of the actin-binding protein NEXN and that NEXN exerts a protective role against atherosclerosis. An expression microarray analysis showed that the expression of both NEXN-AS1 and NEXN was reduced in human atherosclerotic plaques. In vitro experiments revealed that NEXN-AS1 interacted with the chromatin remodeler BAZ1A and the 5' flanking region of the NEXN gene and that it also upregulated NEXN expression. Augmentation of NEXN-AS1 expression inhibited TLR4 oligomerization and NF-κB activity, downregulated the expression of adhesion molecules and inflammatory cytokines by endothelial cells, and suppressed monocyte adhesion to endothelial cells. These inhibitory effects of NEXN-AS1 were abolished by knockdown of NEXN. In vivo experiments using ApoE-knockout mice fed a Western high-fat diet demonstrated that NEXN deficiency promoted atherosclerosis and increased macrophage abundance in atherosclerotic lesions, with heightened expression of adhesion molecules and inflammatory cytokines, whereas augmented NEXN expression deterred atherosclerosis. Patients with coronary artery disease were found to have lower blood NEXN levels than healthy individuals. These results indicate that NEXN-AS1 and NEXN represent potential therapeutic targets in atherosclerosis-related diseases.

Proteomic analysis of rat serum revealed the effects of chronic sleep deprivation on metabolic, cardiovascular and nervous system

Sleep is an essential and fundamental physiological process that plays crucial roles in the balance of psychological and physical health. Sleep disorder may lead to adverse health outcomes. The effects of sleep deprivation were extensively studied, but its mechanism is still not fully understood. The present study aimed to identify the alterations of serum proteins associated with chronic sleep deprivation, and to seek for potential biomarkers of sleep disorder mediated diseases. A label-free quantitative proteomics technology was used to survey the global changes of serum proteins between normal rats and chronic sleep deprivation rats. A total of 309 proteins were detected in the serum samples and among them, 117 proteins showed more than 1.8-folds abundance alterations between the two groups. Functional enrichment and network analyses of the differential proteins revealed a close relationship between chronic sleep deprivation and several biological processes including energy metabolism, cardiovascular function and nervous function. And four proteins including pyruvate kinase M1, clusterin, kininogen1 and profilin-1were identified as potential biomarkers for chronic sleep deprivation. The four candidates were validated via parallel reaction monitoring (PRM) based targeted proteomics. In addition, protein expression alteration of the four proteins was confirmed in myocardium and brain of rat model. In summary, the comprehensive proteomic study revealed the biological impacts of chronic sleep deprivation and discovered several potential biomarkers. This study provides further insight into the pathological and molecular mechanisms underlying sleep disorders at protein level.

Silencing profilin-1 confers protection from oxLDL injury in human vascular endothelial cells

Oxidized low density lipoprotein (oxLDL) plays a key role in the dysfunction, injury and apoptosis of vascular endothelial cells (ECs). Profilin-1, an actin-binding protein, is up-regulated during these processes of endothelial cells. The aim for this study is to investigate expression of profilin-1 in human vascular endothelial cells (HUVECs) in present of oxLDL and the protection effect by Silencing profilin-1 on HUVECs exposed to oxLDL and its mechanism. HUVECs were cultured and exposed to oxLDL (50 µg/ml) for 24 h and subsequently were treated with siRNA to inhibit gene profilin-1. Expression of protein and mRNA for profilin-1 and genes (caspase-3, Bax, Bcl-2, NF-κB and survivin) associated with apoptosis were determined using real-time PCR and western blot analysis, respectively. The cells injuries and apoptosis were examined by flow cytometry analysis. After exposed to oxLDL, the mRNA and protein levels of profilin-1 in HUVECs were significantly increased. Suppressed profilin-1 expression in oxLDL treated HUVECs by RNA-interference resulted in significant reduction and elevation of the mRNA and protein of caspase-3 and Bax, Bcl-2 and NF-κB and survivin, respectively. In addition, this is the first time that reports survivin involving oxLDL induced ECs injuries. Flow cytometry analysis showed the apoptosis ratio of oxLDL treated HUVECs significantly decreased after silencing profilin-1. These findings suggest that profilin-1 may play a key role in process of ECs injuries and apoptosis caused by oxLDL, and mechanism of its action involves various apoptosis related genes and deserves more attention.

Notch2 and Proteomic Signatures in Mouse Neointimal Lesion Formation

Supplemental Digital Content is available in the text.

Objective—

Vascular remodeling is associated with complex molecular changes, including increased Notch2, which promotes quiescence in human smooth muscle cells. We used unbiased protein profiling to understand molecular signatures related to neointimal lesion formation in the presence or absence of Notch2 and to test the hypothesis that loss of Notch2 would increase neointimal lesion formation because of a hyperproliferative injury response.

Approach and Results—

Murine carotid arteries isolated at 6 or 14 days after ligation injury were analyzed by mass spectrometry using a data-independent acquisition strategy in comparison to uninjured or sham injured arteries. We used a tamoxifen-inducible, cell-specific Cre recombinase strain to delete the Notch2 gene in smooth muscle cells. Vessel morphometric analysis and immunohistochemical staining were used to characterize lesion formation, assess vascular smooth muscle cell proliferation, and validate proteomic findings. Loss of Notch2 in smooth muscle cells leads to protein profile changes in the vessel wall during remodeling but does not alter overall lesion morphology or cell proliferation. Loss of smooth muscle Notch2 also decreases the expression of enhancer of rudimentary homolog, plectin, and annexin A2 in vascular remodeling.

Conclusions—

We identified unique protein signatures that represent temporal changes in the vessel wall during neointimal lesion formation in the presence and absence of Notch2. Overall lesion formation was not affected with loss of smooth muscle Notch2, suggesting compensatory pathways. We also validated the regulation of known injury- or Notch-related targets identified in other vascular contexts, providing additional insight into conserved pathways involved in vascular remodeling.

Differential expression of genes identified by suppression subtractive hybridization in liver and adipose tissue of gerbils with diabetes

Objectives

We aimed at identifying genes related to hereditary type 2 diabetes expressed in the liver and the adipose tissue of spontaneous diabetic gerbils using suppression subtractive hybridization (SSH) screening.

Methods

Two gerbil littermates, one with high and the other with normal blood glucose level, from our previously bred spontaneous diabetic gerbil strain were used in this study. To identify differentially expressed genes in the liver and the adipose tissue, mRNA from these tissues was extracted and SSH libraries were constructed for screening. After sequencing and BLAST analyzing, up or down-regulated genes possibly involved in metabolism and diabetes were selected, and their expression levels in diabetic gerbils and normal controls were analyzed using quantitative RT-PCR and Western blotting.

Results

A total of 4 SSH libraries were prepared from the liver and the adipose tissue of gerbils. There are 95 up or down-regulated genes were identified to be involved in metabolism, oxidoreduction, RNA binding, cell proliferation, and differentiation or other function. Expression of 17 genes most possibly associated with diabetes was analyzed and seven genes (Sardh, Slc39a7, Pfn1, Arg1, Cth, Sod1 and P4hb) in the liver and one gene (Fabp4) in the adipose tissue were identified that were significantly differentially expressed between diabetic gerbils and control animals.

Conclusions

We identified eight genes associated with type 2 diabetes from the liver and the adipose tissue of gerbils via SSH screening. These findings provide further insights into the molecular mechanisms of diabetes and imply the value of our spontaneous diabetic gerbil strain as a diabetes model.

The association of profilin-1 levels with survival in chronic kidney disease

BACKGROUND

Profilin-1 is a ubiquitous, actin-binding protein that plays an important role in the regulation of actin polymerization and cytoskeleton remodelling and contributes to vascular dysfunction. We conducted this study to investigate the association of serum profilin-1 levels with fatal and nonfatal CVE in a cohort of patients with stage 1-5 CKD.

MATERIALS AND METHODS

Serum concentrations of profilin-1 levels were determined by enzyme-linked immunosorbent assay. Endothelium-dependent vasodilatation (flow-mediated dilatation [FMD]) and endothelium-independent vasodilatation (nitroglycerine-mediated dilatation [NMD]) of the brachial artery were assessed noninvasively, using high-resolution ultrasound.

RESULTS

Both fatal and nonfatal CVE were significantly higher in patients with high profilin-1 levels. Kaplan-Meier survival curves showed that patients with profilin-1 below the median value (114 pg/mL) had higher cumulative survival compared with patients who had profilin-1 levels above the median value (log-rank test, P < .001).

CONCLUSIONS

This is the first study that demonstrates the serum profilin-1 is independently associated with endothelial dysfunction, cardiovascular events and survival in patients with CKD.

ANGPTL-4 induces diabetic retinal inflammation by activating Profilin-1

Diabetic retinopathy (DR), the most common cause of irreversible blindness in working-age adults, results in central vision loss that is caused by microvascular damage to the inner lining of the back of the eye, the retina. The aim of this work was to assess the temporal relationships between angiopoietin-like protein-4 (ANGPTL-4), a novel adipocytokine factor, and diabetic retinal inflammation and microvascular dysfunction. The downstream pathway(s) and upstream mediator(s) of ANGPTL-4 were then determined under high glucose (HG) conditions. Diabetic rats and control animals were randomly assigned to receive hypoxia inducible factor-1 alpha (HIF-1α) blockade (doxorubicin or shRNA) or vehicle for 8 weeks. Human retinal microvascular endothelial cells (HRMECs) were incubated with normal or high glucose, with or without blockade or recombinant proteins, for ANGPTL-4, HIF-1α, and vascular endothelial growth factor (VEGF). The levels of ANGPTL-4, profilin-1, HIF-1α, VEGF, interleukin 1 beta (IL-1β), IL-6, and intercellular adherent molecule 1 (ICAM-1) in the rat retinas and HRMEC extracts were examined by Western blotting and real-time RT-PCR. The levels of ANGPTL-4, profilin-1, HIF-1α, and VEGF protein and mRNA were significantly higher in the diabetic rats and HG-exposed HRMECs. ANGPTL-4 was a potent modulator of increased inflammation, permeability, and angiogenesis via activation of the profilin-1 signaling pathway. Our results showed that ANGPTL-4 upregulation was induced by HG, which was dependent on HIF-1α activation that was also triggered by HG, both in vivo and in vitro. Our results suggest that targeting ANGPTL-4, alone or in combination with profilin-1, may be an effective therapeutic strategy and diagnostic screening biomarker for proliferative diabetic retinopathy and other vitreous-retinal inflammatory diseases.

Profilin‑1 contributes to cardiac injury induced by advanced glycation end‑products in rats

Cardiac injury, including hypertrophy and fibrosis, induced by advanced glycation end products (AGEs) has an important function in the onset and development of diabetic cardiomyopathy. Profilin-1, a ubiquitously expressed and multifunctional actin-binding protein, has been reported to be an important mediator in cardiac hypertrophy and fibrosis. However, whether profilin-1 is involved in AGE-induced cardiac hypertrophy and fibrosis remains to be determined. Therefore, the present study aimed to investigate the function of profilin-1 in cardiac injury induced by AGEs. The model of cardiac injury was established by chronic tail vein injection of AGEs (50 mg/kg/day for 8 weeks) in Sprague-Dawley rats. Rats were randomly assigned to control, AGEs, AGEs + profilin-1 shRNA adenovirus vectors (AGEs + S)or AGEs + control adenovirus vectors (AGEs + V) groups. Profilin-1 shRNA adenovirus vectors were injected via the tail vein to knockdown profilin-1 expression at a dose of 3×10⁹ plaque forming units every 4 weeks. Echocardiography was performed to measure cardiac contractile function. Cardiac tissues were stained with Masson's trichrome stain to evaluate ventricular remodeling. The serum levels of procollagen type III N-terminal peptide were detected by ELISA. The expression of profilin-1, receptor for AGEs (RAGE), Rho, p65, atrial natriuretic peptide, β-myosin heavy chain, matrix metalloproteinase (MMP)-2 and MMP-9 were determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and/or western blot analysis and immunohistochemistry staining. The results demonstrated that chronic injection of exogenous AGEs led to cardiac dysfunction, hypertrophy and fibrosis, as determined by echocardiography, Masson trichrome staining and the expression of associated genes. The expression of profilin-1 was markedly increased in heart tissue at the mRNA and protein level following AGE administration, as determined by RT-qPCR and western blotting, which was further confirmed by immunohistochemistry staining. Furthermore, the expression of RAGE, Rho and p65 was also increased at the protein level. Notably, knockdown of profilin-1 expression ameliorated AGE-induced cardiac injury and reduced the expression of RAGE, Rho and p65. These results indicate an important role for profilin-1 in AGE-induced cardiac injury, which may provide a novel therapeutic target for patients with diabetic heart failure.

Invasive trophoblast promote stromal fibroblast decidualization via Profilin 1 and ALOX5

During the establishment of pregnancy, extravillous trophoblast (EVT) must invade into the uterine decidua to facilitate decidual artery remodelling to create the placental blood supply. The local decidual environment is thought to regulate trophoblast invasion, however these interactions are poorly defined in humans. Recent evidence in women suggests impaired decidualization is associated with miscarriage and preeclampsia. Primary human endometrial stromal cells (HESC) and first trimester extravillous trophoblast (EVTs) were used to assess the effect of EVT-secreted factors on HESC decidualization, adhesion, proliferation and migration. We determined the role of profilin (PFN)1, an EVT-secreted factor, on HESC function and identified a downstream target of PFN1. EVT-secreted factors induced HESC decidualization and enhanced decidualized HESC adhesion, proliferation and migration. Recombinant PFN1 enhanced methoxyprogesterone acetate-induced HESC decidualization and proliferation. PFN1 down-regulated the expression of lipoxygenase arachidonate 5-lipoxygenase (ALOX5) in HESC and THP-1 macrophages. ALOX5 localised to decidual cells and CD68+macrophages in 1^st trimester decidua. This study demonstrated that EVT secretions, including PFN1, enhanced HESC decidualization and motility. This study has identified a new pathway that facilitates appropriate decidualization during the establishment of pregnancy.

The myocardin-related transcription factor MKL co-regulates the cellular levels of two profilin isoforms

Megakaryoblastic leukemia (MKL)/serum-response factor (SRF)-mediated gene transcription is a highly conserved mechanism that connects dynamic reorganization of the actin cytoskeleton to regulation of expression of a wide range of genes, including SRF itself and many important structural and regulatory components of the actin cytoskeleton. In this study, we examined the possible role of MKL/SRF in the context of regulation of profilin (Pfn), a major controller of actin dynamics and actin cytoskeletal remodeling in cells. We demonstrated that despite being located on different genomic loci, two major isoforms of Pfn (Pfn1 and Pfn2) are co-regulated by a common mechanism involving the action of MKL that is independent of its SRF-related activity. We found that MKL co-regulates the expression of Pfn isoforms indirectly by modulating signal transducer and activator of transcription 1 (STAT1) and utilizing its SAP-domain function. Unexpectedly, our studies revealed that cellular externalization, rather than transcription of Pfn1, is affected by the perturbations of MKL. We further demonstrated that MKL can influence cell migration by modulating Pfn1 expression, indicating a functional connection between MKL and Pfn1 in actin-dependent cellular processes. Finally, we provide initial evidence supporting the ability of Pfn to influence MKL and SRF expression. Collectively, these findings suggest that Pfn may play a role in a possible feedback loop of the actin/MKL/SRF signaling circuit.

Profilin modulates sarcomeric organization and mediates cardiomyocyte hypertrophy

Aims

Heart failure is often preceded by cardiac hypertrophy, which is characterized by increased cell size, altered protein abundance, and actin cytoskeletal reorganization. Profilin is a well-conserved, ubiquitously expressed, multifunctional actin-binding protein, and its role in cardiomyocytes is largely unknown. Given its involvement in vascular hypertrophy, we aimed to test the hypothesis that profilin-1 is a key mediator of cardiomyocyte-specific hypertrophic remodelling.

Methods and results

Profilin-1 was elevated in multiple mouse models of hypertrophy, and a cardiomyocyte-specific increase of profilin in Drosophila resulted in significantly larger heart tube dimensions. Moreover, adenovirus-mediated overexpression of profilin-1 in neonatal rat ventricular myocytes (NRVMs) induced a hypertrophic response, measured by increased myocyte size and gene expression. Profilin-1 silencing suppressed the response in NRVMs stimulated with phenylephrine or endothelin-1. Mechanistically, we found that profilin-1 regulates hypertrophy, in part, through activation of the ERK1/2 signalling cascade. Confocal microscopy showed that profilin localized to the Z-line of Drosophila myofibrils under normal conditions and accumulated near the M-line when overexpressed. Elevated profilin levels resulted in elongated sarcomeres, myofibrillar disorganization, and sarcomeric disarray, which correlated with impaired muscle function.

Conclusion

Our results identify novel roles for profilin as an important mediator of cardiomyocyte hypertrophy. We show that overexpression of profilin is sufficient to induce cardiomyocyte hypertrophy and sarcomeric remodelling, and silencing of profilin attenuates the hypertrophic response.

Mechanism of Profilin-1 in regulating eNOS/NO signaling pathway and its role in hypertensive myocardial hypertension

OBJECTIVE

To explore the mechanism of Profilin-1 in regulating eNOS/NO pathway and its role in the development of myocardial hypertrophy.

METHODS

Spontaneously hypertensive rats (SHR) aged 5 weeks were injected with different adenovirus vectors to induce Profilin-1 expression knockdown (SHR-I) or over express (SHR-H) or to use as control (SHR-C). All these treatment were compared with Wistar-Kyoto rats (SKY) treated with control adenovirus vectors (WKY-C). The same injection was executed at the sixth week during the experiment of 12 weeks. After experiment, the left ventricular weight-to-heart weight ratio (LVW/HW) and left ventricular long axis (LVLA) were measured. Meanwhile, NO contents in blood and myocardium, Profilin-1, eNOS and Caveolin-3 mRNA and protein levels and phosphorylated eNOS (P-eNOS) protein level in myocardium were determined.

RESULTS

Compared with WKY-C group, the SHR-C group was statistically higher in LVW/HW (0.79±0.03), LVLA (11.82±0.58 mm) and Profilin-1 mRNA and protein level (P<0.05), but lower in NO content [(18.63±6.23) μmol/L] in blood and [(2.71±0.17) μmol/L] in myocardium), eNOS activity and Caveolin-3 expression (P<0.05). The over expressing Profilin-1 led SHR-H group to a higher value of LVW/HW [(0.93±0.03) mm and LVLA (14.17±0.69) mm] in comparison with SHR-C group (P<0.05), and to a lower value of NO content (in myocardium), eNOS activity and Caveolin-3 expression (P<0.05); however, this phenomenon was reversed by the knockdown Profilin-1 expression (SHR-I group).

CONCLUSIONS

Profilin-1 expression, being negative in regulating Caveolin-3 expression and eNOS/NO pathway activity, promotes the development of myocardial hypertrophy which can be reversed by Profilin-1 silencing.

Changes in thrombus composition and profilin-1 release in acute myocardial infarction

AIM

Thrombus formation is a dynamic process regulated by flow, blood cells, and plasma proteins. The present study was performed to investigate the characteristics of human coronary thrombus in ST-segment elevation myocardial infarction (STEMI).

METHODS AND RESULTS

Patients admitted with ST-elevation myocardial infarction, in which thrombectomy was performed, were included (n = 86). Intracoronary thrombi and blood from the culprit coronary site and the systemic circulation were obtained during percutaneous coronary intervention (PCI). Thrombi were categorized by onset-of-pain-to-PCI elapsed time in thrombus of <3 (T3) and more than 6 h of evolution (T6). Clinical, morphological, and proteomic variables were investigated. While T3 were mainly composed by platelets and fibrin(ogen), T6 were characterized by a reduced platelet content, increased leucocytes infiltration (including monocytes, neutrophils, T-cells, and B-cells), and appearance of undifferentiated progenitor cells. Significant differences between T3 and T6 were found in the cell cytoskeleton-associated proteome (beta-actin and tropomyosin 3 and 4). By discovery proteomics, we have identified profilin-1 (Pfn-1) in the coronary thrombi and detected higher levels in T3 than in T6. While plasma Pfn-1 levels were low in T3 patients, levels significantly increased in both coronary and peripheral circulation in T6 patients indicating release. In vitro platelet aggregation studies showed that platelets secrete Pfn-1 upon complete activation.

CONCLUSION

Coronary thrombi show rapid dynamic changes both in structure and cell composition as a function of elapsed onset-of-pain-to-PCI time. Aged ischaemic thrombi were more likely to have reduced Pfn-1 content releasing Pfn-1 to the circulation. Onset-of-pain-to-PCI elapsed time in STEMI patients and hence age of occlusive thrombus can be profiled by Pfn-1 levels found in the peripheral circulation.

A potential therapeutic effect of CYP2C8 overexpression on anti-TNF-α activity

Epoxyeicosatrienoic acids (EETs) are generated from arachidonic acid catalysed by cytochrome P450 (CYP) epoxygenases. In addition to regulating vascular tone EETs may alleviate inflammation and ROS. The present study was conducted to determine whether CYP2C8 gene overexpression was able to increase the level of EETs, and subsequently prevent TNF-α induced inflammation and reactive oxygen species (ROS) in human umbilical vein endothelial cells (HUVECs) and macrophages. Peroxisome proliferator-activated receptor γ (PPARγ) activation, nuclear factor-κB (NF-κB) activation, endothelial nitric oxide synthase (eNOS) activation, gp-91 activation, and inflammatory cytokine expression were detected by western blot analysis or enzyme-linked immunosorbent assay. Intracellular reactive oxygen species (ROS) was measured by flow cytometry, while the migration of vascular smooth muscle cells (VSMCs) was detected by Transwell assay. pCMV-mediated CYP2C8 overexpression and its metabolites, EETs, markedly suppressed TNF-α induced inflammatory cytokines IL-6 and MCP-1 expression via the activation of NF-κB and degradation of IκBα. Moreover, pretreatment with 11,12-EET significantly blocked TNF-α-induced ROS production. CYP2C8-derived EETs also effectively alleviated the migration of VSMCs and improved the function of endothelial cells through the upregulation of eNOS, which was significantly decreased under the stimulation of TNF-α. Furthermore, these protective effects observed were mediated by PPARγ activation. To the best of our knowledge, the results of the present study demonstrated for the first time that CYP2C8-derived EETs exerted antivascular inflammatory and anti-oxidative effects, at least in part, through the activation of PPARγ. Thus, the CYP2C8 gene may be useful in the prevention and treatment of vascular inflammatory diseases.

Development and validation of a gene expression score that predicts response to fulvestrant in breast cancer patients

Fulvestrant is a selective estrogen receptor antagonist. Based on the measured growth inhibition of 60 human cancer cell lines (NCI60) in the presence of fulvestrant, as well as the baseline gene expression of the 60 cell lines, a gene expression score that predicts response to fulvestrant was developed. The score is based on 414 genes, 103 of which show increased expression in sensitive cell lines, while 311 show increased expression in the non-responding cell lines. The sensitivity genes primarily sense signaling through estrogen receptor alpha, whereas the resistance genes modulate the PI3K signaling pathway. The latter genes suggest that resistance to fulvestrant can be overcome by drugs targeting the PI3K pathway. The level of this gene expression score and its correlation with fulvestrant response was measured in a panel of 20 breast cancer cell lines. The predicted sensitivity matched the measured sensitivity well (CC = -0.63, P = 0.003). The predictor was applied to tumor biopsies obtained from a Phase II clinical trial. The sensitivity of each patient to treatment with fulvestrant was predicted based on the RNA profile of the biopsy taken before neoadjuvant treatment and without knowledge of the subsequent response. The prediction was then compared to clinical response to show that the responders had a significantly higher sensitivity prediction than the non-responders (P = 0.01). When clinical covariates, tumor grade and estrogen receptor H-score, were included in the prediction, the difference in predicted senstivity between responders and non-responders improved (P = 0.003). Using a pre-defined cutoff to separate patients into predicted sensitive and predicted resistant yielded a positive predictive value of 88% and a negative predictive value of 100% when compared to clinical data. We conclude that pre-screening patients with the new gene expression predictor has the potential to identify those postmenopausal women with locally advanced, estrogen-receptor-positive breast cancer most likely to respond to fulvestrant.

The multifaceted role of profilin-1 in adipose tissue inflammation and glucose homeostasis

Profilin-1 (pfn) is a small ubiquitous protein that can bind to: (1) G-actin, (2) phosphatidylinositol 4,5-bisphosphate, and (3) a heterogeneous group of proteins harboring poly-l-proline stretches. Through these interactions, pfn integrates signaling from a diverse array of extracellular cues with actin cytoskeleton dynamics. Cumulating evidence indicates that changes in pfn levels are associated and may play a pathogenic role in such inflammatory diseases as atherosclerosis and glomerulonephritis. We recently demonstrated that high fat diet (HFD) increases pfn expression in the white adipose tissue (WAT), but not in the liver or the muscle. Pfn heterozygote mice (PfnHet) were protected against HFD-induced glucose intolerance, and WAT and systemic inflammation, when compared to pfn wild-type mice. In addition to blunted accumulation of macrophages and reduced "pro-inflammatory" cytokines, the WAT of PfnHet exhibited preserved frequency of regulatory T cells. These findings suggest that pfn levels in WAT-both adipocytes and hematopoietic-derived cells-can modulate immune homeostasis within the WAT and glucose tolerance systemically. Here, we review the interaction of pfn with his diverse array of binding partners and discuss mechanisms that may underlie the effects of pfn dosage on insulin sensitivity and metabolic inflammation.

Profilin-1 haploinsufficiency protects against obesity-associated glucose intolerance and preserves adipose tissue immune homeostasis

Metabolic inflammation may contribute to the pathogenesis of obesity and its comorbidities, including type 2 diabetes and cardiovascular disease. Previously, we showed that the actin-binding protein profilin-1 (pfn) plays a role in atherogenesis because pfn heterozygote mice (PfnHet) exhibited a significant reduction in atherosclerotic lesion burden and vascular inflammation. In the current study, we tested whether pfn haploinsufficiency would also limit diet-induced adipose tissue inflammation and insulin resistance (IR). First, we found that a high-fat diet (HFD) upregulated pfn expression in epididymal and subcutaneous white adipose tissue (WAT) but not in the liver or muscle of C57BL/6 mice compared with normal chow. Pfn expression in WAT correlated with F4/80, an established marker for mature macrophages. Of note, HFD elevated pfn protein levels in both stromal vascular cells and adipocytes of WAT. We also found that PfnHet were significantly protected from HFD-induced glucose intolerance observed in pfn wild-type mice. With HFD, PfnHet displayed blunted expression of systemic and WAT proinflammatory cytokines and decreased accumulation of adipose tissue macrophages, which were also preferentially biased toward an M2-like phenotype; this correlated with preserved frequency of regulatory T cells. Taken together, the findings indicate that pfn haploinsufficiency protects against diet-induced IR and inflammation by modulating WAT immune homeostasis.

The role of profilin-1 in endothelial cell injury induced by advanced glycation end products (AGEs)

BACKGROUND

Accumulation of advanced glycation end products (AGEs) in the vasculature triggers a series of morphological and functional changes contributing to endothelial hyperpermeability. The reorganisation and redistribution of the cytoskeleton regulated by profilin-1 mediates endothelial cell contraction, which results in vascular hyperpermeability. This study aimed to investigate the pivotal role of profilin-1 in the process of endothelial cell damage induced by AGEs.

METHODS

Human umbilical vein endothelial cells (HUVECs) were incubated with AGEs. The mRNA and protein expression of profilin-1 was determined using real-time PCR and western blotting analyses. The levels of intercellular adhesion molecule-1 (ICAM-1), nitric oxide (NO) and reactive oxygen species (ROS), as well as the activities of nuclear factor-κB (NF-κB) and protein kinase C (PKC), were detected using the appropriate kits. The levels of asymmetric dimethylarginine (ADMA) were determined using HPLC. The distribution of the cytoskeleton was visualised using immunofluorescent staining.

RESULTS

Compared with the control, incubation of endothelial cells with AGEs (200 μg/ml) for 4 or 24 h significantly up-regulated the mRNA and protein expression of profilin-1, markedly increased the levels of ICAM-1 and ADMA and decreased the production of NO (P<0.05, P<0.01), which was significantly attenuated by pretreatment with DPI (an antioxidant), GF 109203X (PKC inhibitor) or BAY-117082 (NF-κB inhibitor). DPI (10 μmol/L) markedly decreased the elevated levels of ROS induced by AGEs (200 μg/ml, 24 h); however, GF 109203X (10 μmol/L) and BAY-117082 (5 μmol/L) exhibited no significant effect on the formation of ROS by AGEs. Immunofluorescent staining indicated that AGEs markedly increased the expression of profilin-1 in the cytoplasm and the formation of actin stress fibres, resulting in the rearrangement and redistribution of the cytoskeleton. This effect was significantly ameliorated by DPI, GF 109203X, BAY-117082 or siRNA treatment of profilin-1. Incubation with DPI and GF 109203X markedly inhibited the activation of PKC triggered by AGEs, and DPI and BAY-117082 significantly decreased the activity of NF-κB mediated by AGEs. Disruption of profilin-1 gene expression attenuated the extent of endothelial abnormalities by reducing ICAM-1 and ADMA levels and elevating NO levels (P<0.05, P<0.01), but this disruption had no effect on the activities of NF-κB and PKC (P>0.05).

CONCLUSIONS

These findings suggested that profilin-1 might act as an ultimate and common cellular effector in the process of metabolic memory (endothelial abnormalities) mediated by AGEs via the ROS/PKC or ROS/NF-қB signalling pathways.

Profilin-1 promotes the development of hypertension-induced cardiac hypertrophy

OBJECTIVE

Cardiac hypertrophy is a major cause of heart failure and sudden cardiac death among hypertensive individuals. The present study examined the effects of profilin-1 on hypertension-induced cardiac hypertrophy.

METHODS

We used adenovirus injection to knockdown or overexpress profilin-1 in spontaneous hypertensive rats (SHRs). As a control, blank adenovirus was injected into age-matched SHRs and Wistar-Kyoto rats (WKYs). SBP and cardiac mass index were measured. Cardiac tissues were stained with hematoxylin-eosin and sirius red, and cardiac ultrastructure was imaged using transmission electron microscopy. Actin filament was quantified by staining with TRIC-tagged phalloidin. Caveolin-3 abundance and endothelial nitric oxide synthase (eNOS) activity were measured using real-time quantitative PCR, Western blot or immunofluorescence staining.

RESULTS

Endogenous profilin-1 was highly expressed in hypertrophic myocardium of SHRs compared with WKYs. Lowering profilin-1 expression in SHRs significantly attenuated hypertension-induced cardiac hypertrophy and fibrosis and displayed a significant preservation of myofibrils, sarcolemmal caveolae, abundance of caveolin-3 protein, activity of eNOS and production of nitric oxide (NO). In contrast, transgenic overexpression of profilin-1 in SHRs induced more serious cardiac hypertrophy and fibrosis with significant reduction of sarcolemmal caveolae, caveolin-3 protein, eNOS activity, and production of NO when compared with SHR controls.

CONCLUSION

Profilin-1 promotes cardiac hypertrophy partly through interfering with the formation of sarcolemmal caveolae and attenuating the eNOS/NO pathway. These results demonstrate a crucial role for profilin-1 in hypertensive cardiac hypertrophy.

ACE2 deficiency enhances angiotensin II-mediated aortic profilin-1 expression, inflammation and peroxynitrite production

Inflammation and oxidative stress play a crucial role in angiotensin (Ang) II-mediated vascular injury. Angiotensin-converting enzyme 2 (ACE2) has recently been identified as a specific Ang II-degrading enzyme but its role in vascular biology remains elusive. We hypothesized that loss of ACE2 would facilitate Ang II-mediated vascular inflammation and peroxynitrite production. 10-week wildtype (WT, Ace2^+/y) and ACE2 knockout (ACE2KO, Ace2^−/y) mice received with mini-osmotic pumps with Ang II (1.5 mg.kg⁻¹.d⁻¹) or saline for 2 weeks. Aortic ACE2 protein was obviously reduced in WT mice in response to Ang II related to increases in profilin-1 protein and plasma levels of Ang II and Ang-(1–7). Loss of ACE2 resulted in greater increases in Ang II-induced mRNA expressions of inflammatory cytokines monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-1β, and IL-6 without affecting tumor necrosis factor-α in aortas of ACE2KO mice. Furthermore, ACE2 deficiency led to greater increases in Ang II-mediated profilin-1 expression, NADPH oxidase activity, and superoxide and peroxynitrite production in the aortas of ACE2KO mice associated with enhanced phosphorylated levels of Akt, p70S6 kinase, extracellular signal-regulated kinases (ERK1/2) and endothelial nitric oxide synthase (eNOS). Interestingly, daily treatment with AT1 receptor blocker irbesartan (50 mg/kg) significantly prevented Ang II-mediated aortic profilin-1 expression, inflammation, and peroxynitrite production in WT mice with enhanced ACE2 levels and the suppression of the Akt-ERK-eNOS signaling pathways. Our findings reveal that ACE2 deficiency worsens Ang II-mediated aortic inflammation and peroxynitrite production associated with the augmentation of profilin-1 expression and the activation of the Akt-ERK-eNOS signaling, suggesting potential therapeutic approaches by enhancing ACE2 action for patients with vascular diseases.

Transforming growth factor-beta increases the expression of vascular smooth muscle cell markers in human multi-lineage progenitor cells

BACKGROUND

Vascular smooth muscle cell (SMC) differentiation is an essential component of vascular repair and tissue engineering. However, currently used cell models for the study of SMC differentiation have several limitations. Multi-lineage progenitor cells (MLPCs) originate from human umbilical cord blood and are cloned from a single cell. The object of this study was to investigate whether MLPCs could differentiate into SMCs in vitro with induction by transforming growth factor beta1 (TGF-beta1).

MATERIAL/METHODS

MLPCs were treated without or with TGF-beta1 (1 and 5 ng/mL) in mesenchymal stem cell media plus 1% FBS for 7 days. Total RNA was isolated from the MLPCs, and semi-quantitative real-time PCR was performed to test the following mRNA levels: early and late phase SMC-specific markers, two endothelial cell (EC)-specific markers, endothelial progenitor cell (EPC) marker CD34, TGF-beta1 accessory protein CD105, and adhesion molecule CD146.

RESULTS

TGF-beta1 (1 ng/mL) significantly increased the mRNA levels of SMC-specific markers SM22α, calponin-1, SM α-actin, caldesmon, tropomyosin and MLCK as well as adhesion molecule CD146. The mRNA levels of EC-specific markers VE-cadherin and VEGFR-2, EPC marker CD34 and TGF-beta1 accessory protein CD105 were decreased significantly, after MLPC were treated with TGF-beta1 (1 ng/mL). TGF-beta1 at 5 ng/mL showed similar effect on the expression of these genes.

CONCLUSIONS

This study demonstrates that in the presence of TGF-beta1, MLPCs undergo SMC lineage differentiation indicating that MLPCs are a promising cell model for SMC lineage differentiation studies, which may contribute to advances in vascular repair and tissue engineering.