Novel missense variants in brain morphogenic genes associated with depression and schizophrenia

Introduction

Impaired function of brain morphogenic genes is considered one of the predisposing factors for the manifestation of psychiatric and cognitive disorders, such as paranoid schizophrenia (SCZ) and major depressive disorder (MDD). Identification of such genes (genes of neurotrophic factors and guidance molecules among them) and their deleterious genetic variants serves as a key to diagnosis, prevention, and possibly treatment of such disorders. In this study, we have examined the prevalence of genomic variants in brain morphogenic genes in individuals with SCZ and MDD within a Russian population.

Methods

We have performed whole-exome sequencing of 21 DNA samples: 11 from individuals with SCZ and 10 with MDD, followed by ARMS (Amplification-Refractory Mutation System) based screening of detected single nucleotide variants (SNVs) in larger groups: 102 for individuals with SCZ, 79 for those with MDD and 103 for healthy donors.

Results

Whole-exome sequencing has revealed 226 missense mutations in 79 genes (out of 140 studied), some of which occur in patients with psychiatric disorders significantly more frequently than in healthy donors. We have identified previously undescribed genomic variants in brain morphogenic genes: CDH2 (rs1944294-T and rs17445840-T), DCHS2 (rs11935573-G and rs12500437-G/T) and CDH23 (rs1227051-G/A), significantly associated with the incidence of SCZ and MDD in the Russian population. For some SNVs (rs6265-T, rs1944294-T, rs11935573-G, rs4760-G) sex-biased differences in their prevalence between SCZ/MDD patients and healthy donors was detected.

Discussion

However, the functional significance of the SNVs identified has still to be confirmed in cellular and animal models. Once it is fulfilled, these SNVs have the potential to complement the diagnostic toolbox for assessing susceptibility to mental disorders. The data obtained indirectly confirm the importance of adequate brain structure formation for its correct functioning and preservation of mental health.

Morphogenetic theory of mental and cognitive disorders: the role of neurotrophic and guidance molecules

Mental illness and cognitive disorders represent a serious problem for the modern society. Many studies indicate that mental disorders are polygenic and that impaired brain development may lay the ground for their manifestation. Neural tissue development is a complex and multistage process that involves a large number of distant and contact molecules. In this review, we have considered the key steps of brain morphogenesis, and the major molecule families involved in these process. The review provides many indications of the important contribution of the brain development process and correct functioning of certain genes to human mental health. To our knowledge, this comprehensive review is one of the first in this field. We suppose that this review may be useful to novice researchers and clinicians wishing to navigate the field.

Novel Immortalized Human Multipotent Mesenchymal Stromal Cell Line for Studying Hormonal Signaling

Multipotent mesenchymal stromal cells (MSCs) integrate hormone and neuromediator signaling to coordinate tissue homeostasis, tissue renewal and regeneration. To facilitate the investigation of MSC biology, stable immortalized cell lines are created (e.g., commercially available ASC52telo). However, the ASC52telo cell line has an impaired adipogenic ability and a depressed response to hormones, including 5-HT, GABA, glutamate, noradrenaline, PTH and insulin compared to primary cells. This markedly reduces the potential of the ASC52telo cell line in studying the mechanisms of hormonal control of MSC's physiology. Here, we have established a novel immortalized culture of adipose tissue-derived MSCs via forced telomerase expression after lentiviral transduction. These immortalized cell cultures demonstrate high proliferative potential (up to 40 passages), delayed senescence, as well as preserved primary culture-like functional activity (sensitivity to hormones, ability to hormonal sensitization and differentiation) and immunophenotype up to 17-26 passages. Meanwhile, primary adipose tissue-derived MSCs usually irreversibly lose their properties by 8-10 passages. Observed characteristics of reported immortalized human MSC cultures make them a feasible model for studying molecular mechanisms, which regulate the functional activities of these cells, especially when primary cultures or commercially available cell lines are not appropriate.

The Secretome of Mesenchymal Stromal Cells in Treating Intracerebral Hemorrhage: The First Step to Bedside

Intracerebral hemorrhage is an unmet medical need that often leads to the disability and death of a patient. The lack of effective treatments for intracerebral hemorrhage makes it necessary to look for them. Previously, in our proof-of-concept study (Karagyaur M et al. Pharmaceutics, 2021), we have shown that the secretome of multipotent mesenchymal stromal cells (MSC) provides neuroprotection of the brain in a model of intracerebral hemorrhage in rats. Here, we have conducted a systematic study of the therapeutic potential of the MSC secretome in the model of hemorrhagic stroke and provided answers to the questions that need to be addressed in order to translate the secretome-based drug into clinical practice: routes and multiplicity of administration, optimal dose and door-to-treatment time. We have found that MSC secretome reveals prominent neuroprotective activity when administered intranasally or intravenously within 1-3 h after hemorrhage modeling, even in aged rats, and its multiple injections (even within 48 h) are able to reduce the delayed negative effects of hemorrhagic stroke. To our knowledge, this study provides the first systematic investigation of the therapeutic activity of a biomedical MSC-based cell-free drug in intracerebral hemorrhage and is an integral part of its preclinical studies.

Alpha1A- and Beta3-Adrenoceptors Interplay in Adipose Multipotent Mesenchymal Stromal Cells: A Novel Mechanism of Obesity-Driven Hypertension

Hypertension is a major risk factor for cardiovascular diseases, such as strokes and myocardial infarctions. Nearly 70% of hypertension onsets in adults can be attributed to obesity, primarily due to sympathetic overdrive and the dysregulated renin-angiotensin system. Sympathetic overdrive increases vasoconstriction via α1-adrenoceptor activation on vascular cells. Despite the fact that a sympathetic outflow increases in individuals with obesity, as a rule, there is a cohort of patients with obesity who do not develop hypertension. In this study, we investigated how adrenoceptors' expression and functioning in adipose tissue are affected by obesity-driven hypertension. Here, we demonstrated that α1A is a predominant isoform of α1-adrenoceptors expressed in the adipose tissue of patients with obesity, specifically by multipotent mesenchymal stromal cells (MSCs). These cells respond to prolonged exposure to noradrenaline in the model of sympathetic overdrive through the elevation of α1A-adrenoceptor expression and signaling. The extent of MSCs' response to noradrenaline correlates with a patient's arterial hypertension. scRNAseq analysis revealed that in the model of sympathetic overdrive, the subpopulation of MSCs with contractile phenotype expanded significantly. Elevated α1A-adrenoceptor expression is triggered specifically by beta3-adrenoceptors. These data define a novel pathophysiological mechanism of obesity-driven hypertension by which noradrenaline targets MSCs to increase microvessel constrictor responsivity.

Corrigendum: Declined adipogenic potential of senescent MSCs due to shift in insulin signaling and altered exosome cargo

[This corrects the article DOI: 10.3389/fcell.2022.1050489.].

Declined adipogenic potential of senescent MSCs due to shift in insulin signaling and altered exosome cargo

Multipotent mesenchymal stromal cells (MSCs) maintain cellular homeostasis and regulate tissue renewal and repair both by differentiating into mesodermal lineage, e.g., adipocytes, or managing the functions of differentiated cells. Insulin is a key physiological inducer of MSC differentiation into adipocytes, and disturbances in MSC insulin sensitivity could negatively affect adipose tissue renewal. During aging, regulation and renewal of adipose tissue cells may be disrupted due to the altered insulin signaling and differentiation potential of senescent MSCs, promoting the development of serious metabolic diseases, including metabolic syndrome and obesity. However, the potential mechanisms mediating the dysfunction of adipose-derived senescent MSC remains unclear. We explored whether aging could affect the adipogenic potential of human adipose tissue-derived MSCs regulated by insulin. Age-associated senescent MSCs (isolated from donors older than 65 years) and MSCs in replicative senescence (long-term culture) were treated by insulin to induce adipogenic differentiation, and the efficiency of the process was compared to MSCs from young donors. Insulin-dependent signaling pathways were explored in these cells. We also analyzed the involvement of extracellular vesicles secreted by MSCs (MSC-EVs) into the regulation of adipogenic differentiation and insulin signaling of control and senescent cells. Also the microRNA profiles of MSC-EVs from aged and young donors were compared using targeted PCR arrays. Both replicatively and chronologically senescent MSCs showed a noticeably decreased adipogenic potential. This was associated with insulin resistance of MSCs from aged donors caused by the increase in the basal level of activation of crucial insulin-dependent intracellular effectors ERK1/2 and Akt. To assess the impact of the paracrine cross-talk of MSCs, we analyzed microRNAs profile differences in MSC-EVs and revealed that senescent MSCs produced EVs with increased content of miRNAs targeting components of insulin-dependent signaling cascade PTEN, MAPK1, GAREM1 and some other targets. We also confirmed these data by differentiation of control MSCs in the presence of EVs from senescent cells and vice versa. Thus, aging attenuated the adipogenic potential of MSCs due to autocrine or paracrine-dependent induction of insulin resistance associated with the specific changes in MSC-EV cargo.

The Power of Gene Technologies: 1001 Ways to Create a Cell Model

Modern society faces many biomedical challenges that require urgent solutions. Two of the most important include the elucidation of mechanisms of socially significant diseases and the development of prospective drug treatments for these diseases. Experimental cell models are a convenient tool for addressing many of these problems. The power of cell models is further enhanced when combined with gene technologies, which allows the examination of even more subtle changes within the structure of the genome and permits testing of proteins in a native environment. The list and possibilities of these recently emerging technologies are truly colossal, which requires a rethink of a number of approaches for obtaining experimental cell models. In this review, we analyze the possibilities and limitations of promising gene technologies for obtaining cell models, and also give recommendations on the development and creation of relevant models. In our opinion, this review will be useful for novice cell biologists, as it provides some reference points in the rapidly growing universe of gene and cell technologies.

Urokinase-Type Plasminogen Activator Enhances the Neuroprotective Activity of Brain-Derived Neurotrophic Factor in a Model of Intracerebral Hemorrhage

Brain-derived neurotrophic factor (BDNF) is a classic neuroprotective and pro-regenerative factor in peripheral and central nervous tissue. Its ability to stimulate the restoration of damaged nerve and brain tissue after ischemic stroke and intraventricular hemorrhage has been demonstrated. However, the current concept of regeneration allows us to assert that one factor, even if essential, cannot be the sole contributor to this complex biological process. We have previously shown that urokinase-type plasminogen activator (uPA) complements BDNF activity and stimulates restoration of nervous tissue. Using a model of intracerebral hemorrhage in rats, we investigated the neurotrophic and neuroprotective effect of BDNF combined with uPA. The local simultaneous administration of BDNF and uPA provided effective neuroprotection of brain tissue after intracerebral hemorrhage, promoted survival of experimental animals and their neurological recovery, and decreased lesion volume. The study of cellular mechanisms of the observed neurotrophic effect of BDNF and uPA combination revealed both known mechanisms (neuronal survival and neurite growth) and new ones (microglial activation) that had not been shown for BDNF and uPA. Our findings support the concept of using combinations of biological factors with diverse but complementary mechanisms of action as a promising regenerative approach.

Immature Vascular Smooth Muscle Cells in Healthy Murine Arteries and Atherosclerotic Plaques: Localization and Activity

The local development of atherosclerotic lesions may, at least partly, be associated with the specific cellular composition of atherosclerosis-prone regions. Previously, it was demonstrated that a small population of immature vascular smooth muscle cells (VSMCs) expressing both CD146 and neuron-glial antigen 2 is postnatally sustained in atherosclerosis-prone sites. We supposed that these cells may be involved in atherogenesis and can continuously respond to angiotensin II, which is an atherogenic factor. Using immunohistochemistry, flow cytometry, wound migration assay xCELLigence system, and calcium imaging, we studied the functional activities of immature VSMCs in vitro and in vivo. According to our data, these cells do not express nestin, CD105, and the leptin receptor. They are localized in atherosclerosis-prone regions, and their number increases with age, from 5.7% to 23%. Immature VSMCs do not migrate to low shear stress areas and atherosclerotic lesions. They also do not have any unique response to angiotensin II. Thus, despite the localization of immature VSMCs and the presence of the link between their number and age, our study did not support the hypothesis that immature VSMCs are directly involved in the formation of atherosclerotic lesions. Additional lineage tracing studies can clarify the fate of these cells during atherogenesis.

MSC Secretome as a Promising Tool for Neuroprotection and Neuroregeneration in a Model of Intracerebral Hemorrhage

Multipotent mesenchymal stromal cells (MSCs) are considered to be critical contributors to injured tissue repair and regeneration, and MSC-based therapeutic approaches have been applied to many peripheral and central neurologic disorders. It has been demonstrated that the beneficial effects of MSC are mainly mediated by the components of their secretome. In the current study, we have explored the neuroprotective potential of the MSC secretome in a rat model of intracerebral hemorrhage and shown that a 10-fold concentrated secretome of human MSC and its combination with the brain-derived neurotrophic factor (BDNF) provided a better survival and neurological outcome of rats within 14 days of intracerebral hemorrhage compared to the negative (non-treated) and positive (BDNF) control groups. We found that it was due to the ability of MSC secretome to stimulate neuron survival under conditions of glutamate-induced neurotoxicity. However, the lesion volume did not shrink in these rats, and this also correlated with prominent microglia activation. We hypothesize that this could be caused by the species-specificity of the used MSC secretome and provide evidence to confirm this. Thus, we have found that allogenic rat MSC secretome was more effective than xenogenic human MSC secretome in the rat intracerebral hemorrhage model: it reduced the volume of the lesion and promoted excellent survival and neurological outcome of the treated rats.

Decreased Insulin Sensitivity in Telomerase-Immortalized Mesenchymal Stem Cells Affects Efficacy and Outcome of Adipogenic Differentiation in vitro

Modern biomedical science still experiences a significant need for easy and reliable sources of human cells. They are used to investigate pathological processes underlying disease, conduct pharmacological studies, and eventually applied as a therapeutic product in regenerative medicine. For decades, the pool of adult mesenchymal stem/stromal cells (MSCs) remains a promising source of stem and progenitor cells. Their isolation is more feasible than most other stem cells from human donors, yet they have a fair share of drawbacks. They include significant variability between donors, loss of potency, and transformation during long-term culture, which may impact the efficacy and reproducibility of research. One possible solution is a derivation of immortalized MSCs lines which receive a broader use in many medical and biological studies. In the present work, we demonstrated that in the most widely spread commercially available hTERT-immortalized MSCs cell line ASC52telo, sensitivity to hormonal stimuli was reduced, affecting their differentiation efficacy. Furthermore, we found that immortalized MSCs have impaired insulin-dependent and cAMP-dependent signaling, which impairs their adipogenic, but not osteogenic or chondrogenic, potential under experimental conditions. Our findings indicate that hTERT-immortalized MSCs may present a suboptimal choice for studies involving modeling or investigation of hormonal sensitivity.

Scar-Free Healing of Endometrium: Tissue-Specific Program of Stromal Cells and Its Induction by Soluble Factors Produced After Damage

Besides certain exceptions, healing of most tissues in the human body occurs via formation of scar tissue, rather than restoration of lost structures. After extensive acute injuries, this phenomenon substantially limits the possibility of lost function recovery and, in case of chronic injury, it leads to pathological remodeling of organs affected. Managing outcomes of damaged tissue repair is one of the main objectives of regenerative medicine. The first priority for reaching it is comparative investigation of mechanisms responsible for complete restoration of damaged tissues and mechanisms of scarring. However, human body tissues that undergo complete scar-free healing are scarce. The endometrium is a unique mucous membrane in the human body that heals without scarring after various injuries, as well as during each menstrual cycle (i.e., up to 400 times during a woman's life). We hypothesized that absence of scarring during endometrial healing may be associated with tissue-specific features of its stromal cells (SCs) or their microenvironment, since SCs transform into myofibroblasts-the main effector link of scarring. We found that during healing of the endometrium, soluble factors are formed that inhibit the transition of SCs into myofibroblasts. Without influence of these factors, the SCs of the endometrium undergo transformation into myofibroblasts after transforming growth factor β1 (TGF-β1) treatment as well as the SCs from tissues that heal by scarring-skin or fat. However, unlike the latter, endometrial SCs organize extracellular matrix (ECM) in a specific way and are not prone to formation of bulky connective tissue structures. Thus, we may suggest that tissue-specific features of endometrial SCs along with effects of soluble factors secreted in utero during menstruation ensure scar-free healing of human endometrium.

Therapeutic Angiogenesis by a "Dynamic Duo": Simultaneous Expression of HGF and VEGF165 by Novel Bicistronic Plasmid Restores Blood Flow in Ischemic Skeletal Muscle

Therapeutic angiogenesis is a promising strategy for relief of ischemic conditions, and gene delivery was used to stimulate blood vessels’ formation and growth. We have previously shown that intramuscular injection of a mixture containing plasmids encoding vascular endothelial growth factor (VEGF)165 and hepatocyte growth factor (HGF) leads to restoration of blood flow in mouse ischemic limb, and efficacy of combined delivery was superior to each plasmid administered alone. In this work, we evaluated different approaches for co-expression of HGF and VEGF165 genes in a panel of candidate plasmid DNAs (pDNAs) with internal ribosome entry sites (IRESs), a bidirectional promoter or two independent promoters for each gene of interest. Studies in HEK293T culture showed that all plasmids provided synthesis of HGF and VEGF165 proteins and stimulated capillary formation by human umbilical vein endothelial cells (HUVEC), indicating the biological potency of expressed factors. Tests in skeletal muscle explants showed a dramatic difference and most plasmids failed to express HGF and VEGF165 in a significant quantity. However, a bicistronic plasmid with two independent promoters (cytomegalovirus (CMV) for HGF and chicken b-actin (CAG) for VEGF165) provided expression of both grow factors in skeletal muscle at an equimolar ratio. Efficacy tests of bicistronic plasmid were performed in a mouse model of hind limb ischemia. Intramuscular administration of plasmid induced significant restoration of perfusion compared to an empty vector and saline. These findings were supported by increased CD31+ capillary density in animals that received pHGF/VEGF. Overall, our study reports a first-in-class candidate gene therapy drug to deliver two pivotal angiogenic growth factors (HGF and VEGF165) with properties that provide basis for future development of treatment for an unmet medical need—peripheral artery disease and associated limb ischemia.

Cell Sheets from Adipose Tissue MSC Induce Healing of Pressure Ulcer and Prevent Fibrosis via Trigger Effects on Granulation Tissue Growth and Vascularization

We report a comparative study of multipotent mesenchymal stromal cells (MSC) delivered by injection, MSC-based cell sheets (CS) or MSC secretome to induce healing of cutaneous pressure ulcer in C57Bl/6 mice. We found that transplantation of CS from adipose-derived MSC resulted in reduction of fibrosis and recovery of skin structure with its appendages (hair and cutaneous glands). Despite short retention of CS on ulcer surface (3-7 days) it induced profound changes in granulation tissue (GT) structure, increasing its thickness and altering vascularization pattern with reduced blood vessel density and increased maturation of blood vessels. Comparable effects on GT vascularization were induced by MSC secretome, yet this treatment has failed to induce repair of skin with its appendages we observed in the CS group. Study of secretome components produced by MSC in monolayer or sheets revealed that CS produce more factors involved in pericyte chemotaxis and blood vessel maturation (PDGF-BB, HGF, G-CSF) but not sprouting inducer (VEGF165). Analysis of transcriptome using RNA sequencing and Gene Ontology mapping found in CS upregulation of proteins responsible for collagen binding and GT maturation as well as fatty acid metabolism enzymes known to be negative regulators of blood vessel sprouting. At the same time, downregulated transcripts were enriched by factors activating capillary growth, suggesting that in MSC sheets paracrine activity may shift towards matrix remodeling and maturation of vasculature, but not activation of blood vessel sprouting. We proposed a putative paracrine trigger mechanism potentially rendering an impact on GT vascularization and remodeling. Our results suggest that within sheets, MSC may change their functional state and spectrum of soluble factors that influence tissue repair and induce more effective skin healing inclining towards regeneration and reduced scarring.

Blood Circulating Exosomes Contain Distinguishable Fractions of Free and Cell-Surface-Associated Vesicles

BACKGROUND

Considering exosomes as intercellular transporters, inevitably interacting with the plasma membrane and the large available surface of blood cells, we wonder if a fraction of circulating exosomes is associated with the surface of blood cells.

OBJECTIVE

The aim of this study was to develop an efficient protocol for isolating exosomes associated with the surface of blood cells and to further investigate the characteristics of this fraction in a healthy state and during the development of breast cancer, as well as its possible implication for use in diagnostic applications.

METHODS

Blood samples were collected from Healthy Females (HFs) and breast cancer patients (BCPs). Exosomes extracted from blood plasma and eluted from the surface of blood cells were isolated by ultrafiltration with subsequent ultracentrifugation.

RESULTS

Transmission Electron Microscopy (TEM), along with immunogold labeling, demonstrated the presence of exosomes among membrane-wrapped extracellular vesicles (EVs) isolated from both plasma and blood cell eluates. TEM, nanoparticle tracking analysis, and NanoOrange protein quantitation data showed that cell-associated exosomes constituted no less than 2/3 of total blood exosome number. Exosomes, ranging from 50-70 nm in size, prevailed in the blood of breast cancer patients, whereas smaller exosomes (30-50 nm) were mostly observed in the blood of healthy women. Analysis of specific proteins and RNAs in exosomes circulating in blood demonstrated the significant differences in the packing density of the polymers in exosomes of HFs and BCPs. Preliminary data indicated that detection of cancer-specific miRNA (miR-103, miR-191, miR-195) in exosomes associated with the fraction of red blood cells allowed to discriminate HFs and BCPs more precisely compared to cell-free exosomes circulating in plasma.

CONCLUSION

Our data provide the basis for using blood cell-associated exosomes for diagnostic applications.

A magic kick for regeneration: role of mesenchymal stromal cell secretome in spermatogonial stem cell niche recovery

Background

Injury of stem cell niches may disturb tissue homeostasis and regeneration coordinated by specific niche components. Yet, the mechanisms of stem cell niche restoration remain poorly understood. Herein, we examined the role of mesenchymal stromal cells (MSCs) as pivotal regulators of stem cell niche recovery focusing on the effects of their secretome.

Methods

The spermatogonial stem cell (SSC) niche was selected as a model. SSC niches were injured by inducing abdominal cryptorchidism in rats. Briefly, testes of anesthetized rats were elevated into the abdominal cavity through the inguinal canal for 14 days. After descent of testes, MSC or MSC secretome treatment was applied to the animals by local subtunical injections.

Results

Local administration of MSC or MSC secretome was sufficient to recover spermatogenesis and production of functional germ cells. The effects of MSC and their secreted components were comparable, leading to restoration of Sertoli cell pools and recovery of Leydig cell secretory functions.

Conclusion

Our data suggest that MSCs mimic the functions of lost supportive cells within the stem cell niche, transiently providing paracrine stimuli for target cells and triggering tissue regenerative processes after damage.

Correction: Adipose-Derived Stem Cells Stimulate Regeneration of Peripheral Nerves: BDNF Secreted by These Cells Promotes Nerve Healing and Axon Growth De Novo

[This corrects the article DOI: 10.1371/journal.pone.0017899.].

Oligonucleotide Microarrays Identified Potential Regulatory Genes Related to Early Outward Arterial Remodeling Induced by Tissue Plasminogen Activator

Constrictive vascular remodeling limiting blood flow, as well as compensatory outward remodeling, has been observed in many cardiovascular diseases; however, the underlying mechanisms regulating the remodeling response of the vessels remain unclear. Plasminogen activators (PA) are involved in many of the processes of vascular remodeling. We have shown previously that increased levels of tissue-type PA (tPA) contributes to outward vascular remodeling. To elucidate the mechanisms involved in the induction of outward remodeling we characterized changes in the expression profiles of 8799 genes in injured rat carotid arteries 1 and 4 days after recombinant tPA treatment compared to vehicle. Periadventitial tPA significantly increased lumen size and vessel area, encompassed by the external elastic lamina, at both one and 4 days after treatment. Among 41 differentially expressed known genes 1 day after tPA application, five genes were involved in gene transcription, five genes were related to the regulation of vascular tone [for example, thromboxane A2 receptor (D32080) or non-selective-type endothelin receptor (S65355)], and eight genes were identified as participating in vascular innervation [for example, calpain (D14478) or neural cell adhesion molecule L1 (X59149)]. Four days after injury in tPA-treated arteries, four genes, regulating vascular tone, were differentially expressed. Thus, tPA promotes outward arterial remodeling after injury, at least in part, by regulating expression of genes in the vessel wall related to function of the nervous system and vascular tone.

The transcription factor Prep1 controls hepatic insulin sensitivity and gluconeogenesis by targeting nuclear localization of FOXO1

Liver plays a key role in controlling body carbohydrate homeostasis by switching between accumulation and production of glucose and this way maintaining constant level of glucose in blood. Increased blood glucose level triggers release of insulin from pancreatic β-cells. Insulin represses hepatic glucose production and increases glucose accumulation. Insulin resistance is the main cause of type 2 diabetes and hyperglycemia. Currently thiazolidinediones (TZDs) targeting transcriptional factor PPARγ are used as insulin sensitizers for treating patients with type 2 diabetes. However, TZDs are reported to be associated with cardiovascular and liver problems and stimulate obesity. Thus, it is necessary to search new approaches to improve insulin sensitivity. A promising candidate is transcriptional factor Prep1, as it was shown earlier it could affect insulin sensitivity in variety of insulin-sensitive tissues. The aim of the present study was to evaluate a possible involvement of transcriptional factor Prep1 in control of hepatic glucose accumulation and production. We created mice with liver-specific Prep1 knockout and discovered that hepatocytes derived from these mice are much more sensitive to insulin, comparing to their WT littermates. Incubation of these cells with 100 nM insulin results in almost complete inhibition of gluconeogenesis, while in WT cells this repression is only partial. However, Prep1 doesn't affect gluconeogenesis in the absence of insulin. Also, we observed that nuclear content of gluconeogenic transcription factor FOXO1 was greatly reduced in Prep1 knockout hepatocytes. These findings suggest that Prep1 may control hepatic insulin sensitivity by targeting FOXO1 nuclear stability.

Urokinase and urokinase receptor participate in regulation of neuronal migration, axon growth and branching

PURPOSE

Recent findings indicate the significant contribution of urokinase and urokinase receptor (uPA and uPAR) in the processes of nerve regeneration, however, their role in axonal growth and branching is unclear. Using a 3D model of mouse Dorsal Root Ganglia (DRG) explants, differentiated into neurons Neuro 2a cells and transgenic mice lacking the urokinase gene, we studied the involvement of the uPA/uPAR system in the neural cell migration, neurite outgrowth, elongation and branching.

RESULTS

uPA and uPAR are expressed in the growth cones of axons. Using an ex vivo model of DRG explants in Matrigel we have found that uPA inhibition attenuates neural cell migration and axonal growth, pointing to an important role of urokinase in these processes. Apparently, uPA mediates its effects through its specific receptor uPAR: anti-uPAR antibody, which blocks the uPA binding to uPAR, stimulates axon branching and attenuates neural cell migration from DRG explants. Simultaneous inhibition of uPA and uPAR almost completely prevents the axonal outgrowth from explants into the Matrigels. Experiments in vitro using Neuro 2a cells differentiated into neurons demonstrate that administration of exogenous uPA increases the neurite growth rate (elongation), most likely via the interaction of uPA with uPAR. Blocking of uPAR stimulates neurite formation and enhances branching of preexisting neurites. The results obtained on DRG explants from transgenic mice lacking uPA gene support the assumption that uPA stimulates neurite growth via uPA/uPAR interaction and uPAR role in axons branching and neural cell migration.

CONCLUSIONS

The uPA/uPAR system plays an essential role in neural cell migration, axonal growth and branching.

miR-92a regulates angiogenic activity of adipose-derived mesenchymal stromal cells

Mesenchymal stromal cells including those from adipose tissue (MSCs) regulate angiogenesis in adult tissues. MicroRNAs (miRs), small noncoding RNAs that control gene expression by binding to target mRNAs, reducing their stability and/or inhibiting translation, appear to be important regulators of blood vessel growth. In this study, we examined the impact of angio-miRs on paracrine activities of MSCs. Using Illumina microarrays we found that miR-92a is one of the most abundant angio-miRs in human MSCs. We transfected MSC with pre-miR-92a or anti-miR-92a which led to the coordinated changes of known miR-92a target mRNA levels. Then we tested the ability of conditioned medium from transfected cells to stimulate tube formation by HUVECs. MSC overexpressing miR-92a completely lost the ability to stimulate tubes formation by endothelial cells. However, knocking-out miR-92a by transfection with anti-miR-92a did not increase the ability of MSC to stimulate tube formation. Secretion of hepatocyte growth factor (HGF) and angiopoetin-1 was significantly lower in the medium of miR-92a overexpressing MSC, whereas VEGF secretion did not change significantly. The replenishment of HGF but not angiopoietin-1 has restored the ability of conditioned medium from miR-92a overexpressing MSC to stimulate the tube formation. We conclude that overexpression of miR-92a in MSC suppresses angiogenic properties of these cells by down-regulation of HGF secretion.

ChIP-Seq and RNA-Seq analyses identify components of the Wnt and Fgf signaling pathways as Prep1 target genes in mouse embryonic stem cells

The Prep1 (Pknox1) homeodomain transcription factor is essential at multiple stages of embryo development. In the E11.5 embryo trunk, we previously estimated that Prep1 binds about 3,300 genomic sites at a highly specific decameric consensus sequence, mainly governing basal cellular functions. We now show that in embryonic stem (ES) cells Prep1 binding pattern only partly overlaps that of the embryo trunk, with about 2,000 novel sites. Moreover, in ES cells Prep1 still binds mostly to promoters, as in total embryo trunk but, among the peaks bound exclusively in ES cells, the percentage of enhancers was three-fold higher. RNA-seq identifies about 1800 genes down-regulated in Prep1-/- ES cells which belong to gene ontology categories not enriched in the E11.5 Prep1i/i differentiated embryo, including in particular essential components of the Wnt and Fgf pathways. These data agree with aberrant Wnt and Fgf expression levels in the Prep1-/- ES cells with a deficient embryoid bodies (EBs) formation and differentiation. Re-establishment of the Prep1 level rescues the phenotype.

Adipose-derived mesenchymal stromal cells from aged patients with coronary artery disease keep mesenchymal stromal cell properties but exhibit characteristics of aging and have impaired angiogenic potential

Tissue regeneration is impaired in aged individuals. Adipose-derived mesenchymal stromal cells (ADSCs), a promising source for cell therapy, were shown to secrete various angiogenic factors and improve vascularization of ischemic tissues. We analyzed how patient age affected the angiogenic properties of ADSCs. ADSCs were isolated from subcutaneous fat tissue of patients with coronary artery disease (CAD; n = 64, 43-77 years old) and without CAD (n = 31, 2-82 years old). ADSC phenotype characterized by flow cytometry was CD90(+)/CD73(+)/CD105(+)/CD45(-)/CD31(-) for all samples, and these cells were capable of adipogenic and osteogenic differentiation. ADSCs from aged patients had shorter telomeres (quantitative reverse transcription polymerase chain reaction) and a tendency to attenuated telomerase activity. ADSC-conditioned media (ADSC-CM) stimulated capillary-like tube formation by endothelial cells (EA.hy926), and this effect significantly decreased with the age of patients both with and without CAD. Angiogenic factors (vascular endothelial growth factor, placental growth factor, hepatocyte growth factor, angiopoetin-1, and angiogenin) in ADSC-CM measured by enzyme-linked immunosorbent assay significantly decreased with patient age, whereas levels of antiangiogenic factors thrombospondin-1 and endostatin did not. Expression of angiogenic factors in ADSCs did not change with patient age (real-time polymerase chain reaction); however, gene expression of factors related to extracellular proteolysis (urokinase and its receptor, plasminogen activator inhibitor-1) and urokinase-type plasminogen activator receptor surface expression increased in ADSCs from aged patients with CAD. ADSCs from aged patients both with and without CAD acquire aging characteristics, and their angiogenic potential declines because of decreasing proangiogenic factor secretion. This could restrict the effectiveness of autologous cell therapy with ADSCs in aged patients.

Plasma urokinase antigen and C-reactive protein predict angina recurrence after coronary angioplasty

This study evaluates the predictive value of several biochemical indices of the coagulation-fibrinolysis system, platelet function, and inflammatory state for angina recurrence after successful percutaneous transluminal coronary angioplasty (PTCA). We measured preprocedural and follow-up plasma levels of C-reactive protein (CRP), fibrinogen, and urokinase plasminogen activator antigen (uPA), plasminogen activator inhibitor-1 (PAI-1) activity, tissue plasminogen activator activity, and adenosine diphosphate-induced platelet aggregation in 53 patients with chronic stable angina who underwent successful elective PTCA of single hemodynamically significant lesions in coronary arteries. All patients were followed up for 12 months after PTCA. The Cox proportional hazards model was used to assess the association of variables with angina recurrence rate. At the end of the follow-up, 16 patients had angina recurrence. Among 36 clinical, biochemical, and angiographic variables, the duration of stable angina more than 12 months before PTCA (χ (2) = 5.73; P = 0.02, hazard ratio (HR) 3.7, 95 % confidence interval (CI) 1.26-10.6), high baseline levels of CRP (>7 mg/l) (χ (2) = 8.34; P = 0.004, HR 2.9, 95 % CI 1.4-5.9), uPA antigen baseline (>1 ng/ml) (χ (2) = 17.11; P = 0.0001, HR 11.5, 95 % CI 3.6-36.7) and 48 h after PTCA (χ (2) = 15.73; P = 0.0001, HR 8.8, 95 % CI 3.01-25.96), baseline PAI-1 activity (>18 IU/ml) (χ (2) = 9.37; P = 0.002, HR 7.6, 95 % CI 2.07-27.84) were significant predictors of recurrent angina by univariate analyses. According to stepwise multivariate analyses, only the levels of plasma uPA antigen and serum CRP were shown to be significant independent predictors of angina recurrence (multivariate uPA χ (2) = 8.22, P = 0.004, HR 6.2, 95 % CI 1.78-21.67; CRP χ (2) = 4.09, P = 0.04, HR 1.9, 95 % CI 1.02-3.68). High preprocedural plasma uPA and serum CRP levels are indicative of angina recurrence after successful PTCA, and are valuable for the prognosis of restenosis.

In vitro neuronal induction of adipose-derived stem cells and their fate after transplantation into injured mouse brain

The effect of substances known as inducers of neuronal differentiation on cultured human and mouse adipose-derived mesenchymal stem cells (ASCs) and their fate after transplantation into the injured and ischemic mouse brains were studied. ASCs were isolated from the human and mouse adipose tissue. Inducers of neuronal differentiation included β-mercaptoethanol, glial cell line-derived neurotrophic factor (GNDF), brain-derived neurotrophic factor (BDNF), retinoic acid (RA), 5-azacytidine, as well as their combinations. Three days after the induction, the phenotype of the induced cells was analyzed using immunocytochemistry and real-time PCR assay for differential expression of specific genes. The induction efficiency was evaluated by the increased transcription of neuronal differentiation markers: nestin, β-III-tubulin (Tub-B), microtubule-associated protein 2 (MAP2), and neuron-specific enolase (ENO2). The expression of marker genes was tested by immunocytochemical analysis. ASC cultivation in the medium with RA or BDNF in combination with 5- azacytidine for a week increased the mRNA and protein levels of nestin, Tub-B, and ENO2. The transplantation of induced mouse ASCs into the mouse brain increased the lifespan of the cells relative to control uninduced cells and promoted their migration from the transplantation site to the recipient cerebral parenchyma. The transplantation of the induced cells into the mouse brain pre-exposed to endothelin- 1 promoted a more active cell migration into the surrounding ischemic brain tissue. Thus, ASC exposure to RA or BDNF in combination with 5-azacytidine elevated the transcription of the neuronal differentiation markers and improved the viability and integration of ASCs grafted into the mouse brain.

Analysis of the DNA-binding profile and function of TALE homeoproteins reveals their specialization and specific interactions with Hox genes/proteins

The interactions of Meis, Prep, and Pbx1 TALE homeoproteins with Hox proteins are essential for development and disease. Although Meis and Prep behave similarly in vitro, their in vivo activities remain largely unexplored. We show that Prep and Meis interact with largely independent sets of genomic sites and select different DNA-binding sequences, Prep associating mostly with promoters and housekeeping genes and Meis with promoter-remote regions and developmental genes. Hox target sequences associate strongly with Meis but not with Prep binding sites, while Pbx1 cooperates with both Prep and Meis. Accordingly, Meis1 shows strong genetic interaction with Pbx1 but not with Prep1. Meis1 and Prep1 nonetheless coregulate a subset of genes, predominantly through opposing effects. Notably, the TALE homeoprotein binding profile subdivides Hox clusters into two domains differentially regulated by Meis1 and Prep1. During evolution, Meis and Prep thus specialized their interactions but maintained significant regulatory coordination.

Combined transfer of human VEGF165 and HGF genes renders potent angiogenic effect in ischemic skeletal muscle

Increased interest in development of combined gene therapy emerges from results of recent clinical trials that indicate good safety yet unexpected low efficacy of "single-gene" administration. Multiple studies showed that vascular endothelial growth factor 165 aminoacid form (VEGF165) and hepatocyte growth factor (HGF) can be used for induction of angiogenesis in ischemic myocardium and skeletal muscle. Gene transfer system composed of a novel cytomegalovirus-based (CMV) plasmid vector and codon-optimized human VEGF165 and HGF genes combined with intramuscular low-voltage electroporation was developed and tested in vitro and in vivo. Studies in HEK293T cell culture, murine skeletal muscle explants and ELISA of tissue homogenates showed efficacy of constructed plasmids. Functional activity of angiogenic proteins secreted by HEK293T after transfection by induction of tube formation in human umbilical vein endothelial cell (HUVEC) culture. HUVEC cells were used for in vitro experiments to assay the putative signaling pathways to be responsible for combined administration effect one of which could be the ERK1/2 pathway. In vivo tests of VEGF165 and HGF genes co-transfer were conceived in mouse model of hind limb ischemia. Intramuscular administration of plasmid encoding either VEGF165 or HGF gene resulted in increased perfusion compared to empty vector administration. Mice injected with a mixture of two plasmids (VEGF165+HGF) showed significant increase in perfusion compared to single plasmid injection. These findings were supported by increased CD31+ capillary and SMA+ vessel density in animals that received combined VEGF165 and HGF gene therapy compared to single gene therapy. Results of the study suggest that co-transfer of VEGF and HGF genes renders a robust angiogenic effect in ischemic skeletal muscle and may present interest as a potential therapeutic combination for treatment of ischemic disorders.

Adipose-derived stem cells stimulate regeneration of peripheral nerves: BDNF secreted by these cells promotes nerve healing and axon growth de novo

Transplantation of adipose-derived mesenchymal stem cells (ASCs) induces tissue regeneration by accelerating the growth of blood vessels and nerve. However, mechanisms by which they accelerate the growth of nerve fibers are only partially understood. We used transplantation of ASCs with subcutaneous matrigel implants (well-known in vivo model of angiogenesis) and model of mice limb reinnervation to check the influence of ASC on nerve growth. Here we show that ASCs stimulate the regeneration of nerves in innervated mice's limbs and induce axon growth in subcutaneous matrigel implants. To investigate the mechanism of this action we analyzed different properties of these cells and showed that they express numerous genes of neurotrophins and extracellular matrix proteins required for the nerve growth and myelination. Induction of neural differentiation of ASCs enhances production of brain-derived neurotrophic factor (BDNF) as well as ability of these cells to induce nerve fiber growth. BDNF neutralizing antibodies abrogated the stimulatory effects of ASCs on the growth of nerve sprouts. These data suggest that ASCs induce nerve repair and growth via BDNF production. This stimulatory effect can be further enhanced by culturing the cells in neural differentiation medium prior to transplantation.

Diabetes mellitus, cachexia and obesity in heart failure: rationale and design of the Studies Investigating Co-morbidities Aggravating Heart Failure (SICA-HF)

BACKGROUND: Chronic heart failure (CHF) is increasing in prevalence. Patients with CHF usually have co-morbid conditions, but these have been subjected to little research and consequently there is a paucity of guidance on how to manage them. Obesity and diabetes mellitus are common antecedents of CHF and often complicate management and influence outcome. Cachexia is an ominous and often missed sign in patients with CHF. METHODS: This manuscript describes the rationale and the design of Studies Investigating Co-morbidities Aggravating Heart Failure (SICA-HF), a prospective, multicentre, multinational, longitudinal, pathophysiological evaluation study, which is being conducted in 11 centres across six countries in the European Union and in Russia. We aim to recruit >1,600 patients with CHF due to various common aetiologies, irrespective of left ventricular ejection fraction, and with or without co-morbidities at study entry. In addition, >300 patients with type 2 diabetes mellitus without CHF and >150 healthy subjects will serve as control groups. Participants will be systematically investigated at annual intervals for up to 48 months. Additional investigations focusing on cellular and subcellular mechanisms, adipose and skeletal muscle tissue, and in endothelial progenitor cells will be performed in selected subgroups. CONCLUSIONS: SICA-HF will provide insights into common co-morbidities in CHF with a specific emphasis on diabetes mellitus and body mass. This will provide a more thorough pathophysiological understanding of the complexity of CHF that will help develop therapies tailored to manage specific co-morbidities.

Adipose stromal cells stimulate angiogenesis via promoting progenitor cell differentiation, secretion of angiogenic factors, and enhancing vessel maturation

Adipose-derived stromal cells (ASCs) are suggested to be potent candidates for cell therapy of ischemic conditions due to their ability to stimulate blood vessel growth. ASCs produce many angiogenic and anti-apoptotic growth factors, and their secretion is significantly enhanced by hypoxia. Utilizing a Matrigel implant model, we showed that hypoxia-treated ASCs stimulated angiogenesis as well as maturation of the newly formed blood vessels in vivo. To elucidate mechanisms of ASC angiogenic action, we used a co-culture model of ASCs with cells isolated from early postnatal hearts (cardiomyocyte fraction, CMF). CMF contained mature cardiomyocytes, endothelial cells, and progenitor cells. On the second day of culture CMF cells formed spontaneously beating colonies with CD31+ capillary-like structures outgrowing from those cell aggregates. However, these vessel-like structures were not stable, and disassembled within next 5 days. Co-culturing of CMF with ASCs resulted in the formation of stable and branched CD31+ vessel-like structures. Using immunomagnetic depletion of CMF from vascular cells as well as incubation of CMF with mitomycin C-treated ASCs, we showed that in co-culture ASCs enhance blood vessel growth not only by production of paracrine-acting factors but also by promoting the endothelial differentiation of cardiac progenitor cells. All these mechanisms of actions could be beneficial for the stimulation of angiogenesis in ischemic tissues by ASCs administration.

T-cadherin suppresses angiogenesis in vivo by inhibiting migration of endothelial cells

Our previous studies have revealed the abundant expression of T-cadherin--a glycosylphosphatidylinositol (GPI)-anchored member of cadherin superfamily--in endothelial and mural cells in the heart and vasculature. The upregulation of T-cadherin in vascular proliferative disorders such as atherosclerosis and restenosis suggests the involvement of T-cadherin in vascular growth and remodeling. However, the functional significance of this molecule in the vasculature remains unknown. The effect of T-cadherin on angiogenesis in vivo was evaluated using Matrigel implant model. We demonstrate that T-cadherin overexpression in L929 cells injected in Matrigel inhibits neovascularization of the plug. In vitro T-cadherin inhibits the directional migration of endothelial cells, capillary growth, and tube formation but has no effect on endothelial cell proliferation, adhesion, or apoptosis in vitro. These data suggest that T-cadherin expressed in the stroma could act as a negative guidance cue for the ingrowing blood vessels and thus could have an important potential therapeutic application.

Urokinase Induces Matrix Metalloproteinase-9/Gelatinase B Expression in THP-1 Monocytes via ERK1/2 and Cytosolic Phospholipase A2 Activation and Eicosanoid Production

OBJECTIVE

Urokinase-type plasminogen activator (uPA) regulates cell migration and invasion by pericellular proteolysis and signal transduction events. We characterized the mechanisms by which uPA regulates matrix metalloproteinase-9 (MMP9) function in THP-1 monocytes.

METHODS AND RESULTS

In THP-1 monocytes, MMP9 production induced by urokinase was completely inhibited by the ERK1/2 inhibitor, PD98059, but not by the p38 mitogen-activated protein kinase inhibitor, SB202190. A dominant negative MEK1 adenovirus also blocked MMP9 expression. The effect of urokinase was completely suppressed by genistein and by herbimycin A indicating that tyrosine kinase(s) are required for MMP9 production. Bisindolylmaleimide, a protein kinase C (PKC) inhibitor, did not decrease MMP9 expression suggesting that PKC activation is not required. Key roles for cytosolic phospholipase A2 (PLA2) and eicosanoid production were shown by complete inhibition with methyl arachidonyl fluorophosphonate (an inhibitor of cytosolic PLA2), and indomethacin (a cyclooxygenase inhibitor), with no effect of monoalide, a secretory PLA2 inhibitor. uPA stimulated phosphorylation of cytosolic PLA2.

CONCLUSIONS

Induction of MMP9 by uPA in THP-1 monocytes is via a pathway involving MEK1-ERK1/2-mediated activation of cytosolic PLA2 and eicosanoid generation. These data suggest important roles for eicosanoids in monocyte migration induced by uPA and MMP9.

Urokinase plasminogen activator stimulates vascular smooth muscle cell proliferation via redox-dependent pathways

OBJECTIVE

We showed previously that increased urokinase plasminogen activator (uPA) expression contributes to vascular smooth muscle cell (VSMC) proliferation and neointima formation after injury. Proliferation of cultured rat aortic VSMCs induced by uPA was inhibited by the antioxidant ebselen. Because increases in VSMC reactive oxygen species (ROS) contribute to VSMC proliferation, we hypothesized that uPA increases ROS generation by regulating expression or activity of cellular oxidases.

METHODS AND RESULTS

uPA stimulated ROS production to levels equivalent to angiotensin II as measured by electron spin resonance and fluorescent redox indicators (dichlorofluorescein diacetate, lucigenin, and hydroethidine). The increase in ROS was biphasic, with the first peak at 30 minutes and the second peak at 4 hours. uPA increased expression of the NAD(P)H oxidases Nox1 and Nox4 as measured by RT-PCR and Western blot analysis. Knockdown of Nox1 and Nox4 expression with small interfering RNA showed that both isoforms (Nox1>Nox4) contributed significantly to uPA-stimulated ROS production and VSMC proliferation. Transfection of VSMCs with uPA cDNA to increase endogenous uPA expression enhanced ROS production dramatically, suggesting that autocrine uPA production may be an important mechanism for uPA-mediated VSMC events.

CONCLUSIONS

These data show that uPA is an autocrine VSMC growth factor that increases ROS generated by both Nox1 and Nox4 oxidases.

LDL induces intracellular signalling and cell migration via atypical LDL-binding protein T-cadherin

Cadherins are a superfamily of adhesion molecules that mediate Ca(2+)-dependent cell-cell adhesion. T-cadherin (T-cad), a unique glycosylphosphatidylinositol-anchored member of the cadherin superfamily, was initially identified by immunoblotting of vascular cell membranes as an atypical low affinity low density lipoprotein (LDL)-binding protein. It is not known whether this heterophilic interaction is physiologically relevant. Expression of T-cadherin is upregulated in vascular cells during atherosclerosis, restenosis and tumour angiogenesis, conditions characterized by enhanced cell migration and growth. Elevated levels of serum low density lipoproteins (LDL), which result in cholesterol accumulation in vascular wall, is a widely accepted risk factor in atherosclerosis development. Additionally to its metabolic effects, LDL can produce hormone-like effects in a number of cell types. This study has utilized HEK293 cells and L929 cells stably transfected with T-cadherin cDNA to investigate T-cad-dependent responses to LDL. Stable expression of T-cad in both HEK293 and L929 cells results in significantly (p < 0.05) elevated specific surface binding of [I125]-LDL. Compared with mock-transfectants, cells expressing T-cad exhibit significantly (p < 0.01) enhanced LDL-induced mobilization of intracellular Ca(2+)-stores and a significantly (p < 0.01) increased migration toward an LDL gradient (0.1% BSA + 60 microg/ml LDL) in Boyden chamber migration assay. Thus LDL-binding to T-cad is capable of activating physiologically relevant intracellular signaling and functional responses.

Polyelectrolyte Nanoparticles Mediate Vascular Gene Delivery

PURPOSE

The purpose is to develop a non-viral gene delivery system that meets the requirements of colloidal stability of DNA complexes expressed in terms of no particle aggregation under physiologic conditions. The system should be used to transfect cardiovascular tissues.

METHODS

We used a strategy based on the formation of polyelectrolyte nanoparticles by deposition of alternatively charged polyelectrolytes onto a DNA core. Polyelectrolytes were transfer RNA as well as the synthetic polyanion, polyvinyl sulfate (PVS), and the polycation polyethylenimine (PEI). The PEI/DNA complex formed the DNA core.

RESULTS

We observed that the DNA is condensed by polycations and further packaged by association with a polyanion. These nanoparticles exhibited negative surface charge and low aggregation tendency. In vivo rat carotid artery experiments revealed high transfection efficiency, not only with the reporter gene but also with the gene encoding human urokinase plasminogen activator (Hu-uPA). Hu-uPA is one of the proteins involved in the recovery of the blood vessels after balloon catheter injury and therefore clinically relevant.

CONCLUSIONS

A strategy for in vivo gene transfer is proposed that uses the incorporation of polyanions as RNA or PVS into PEI/DNA complexes in order to overcome colloidal instability and to generate a negative surface charge. The particles proved to be transfectionally active in vascular gene transfer.

Contrasting Effects of Urokinase and Tissue-Type Plasminogen Activators on Neointima Formation and Vessel Remodelling after Arterial Injury

Urokinase-type plasminogen activator (uPA) has been implicated in neointima formation and arterial lumen narrowing after angioplasty. To determine the specificity of the action of uPA on vessel remodelling after arterial injury we compared the effects of the recombinant urokinase- and tissue-type plasminogen activators on vessel morphology, cell migration and proliferation. We used a standard model of the balloon catheter injury of the rat carotid artery followed by the periadventitial application to the injured vessel of the one of the recombinant PAs or recombinant alpha(2)-antiplasmin (alpha-AP) in pluronic gel with further immunohistochemistry and morphometry. The perivascular application of alpha-AP immediately after injury attenuated the healing response, significantly reducing neointima size and neointimal SMC numbers. The periadventitial application to the injured artery of recombinant uPA stimulated neointima formation as well as cell proliferation and migration in vivo and induced greater reductions in lumen size than injury alone. In contrast, recombinant tissue-type plasminogen activator reduced the number of neointimal smooth muscle cells and the neointimal area and increased both the lumen area and the area encompassed by the external elastic laminae after balloon catheter injury of the rat carotid artery. In the meantime both PAs nearly doubled medial and adventitial SMC numbers in the vessels. We conclude that the ability to stimulate neointima formation and inward arterial remodelling is a specific property for urokinase plasminogen activator that could not be mimicked by tissue-type plasminogen activator.

Cell adhesion molecule T-cadherin regulates vascular cell adhesion, phenotype and motility

T-cadherin (T-cad), an unusual glycosylphosphatidylinositol (GPI)-anchored member of the cadherin family of cell adhesion molecules, is widely expressed in the cardiovascular system. The expression profile of T-cad within diseased (atherosclerotic and restenotic) vessels indicates some relationship between expression of T-cad and the phenotypic status of resident cells. Using cultures of human aortic smooth muscle cells (SMC) and human umbilical vein endothelial cells (HUVEC) we investigate the hypothesis that T-cad may function in modulating adhesive properties of vascular cells. Coating of culture plates with recombinant T-cad protein or with antibody against the first amino-terminal domain of T-cad (anti-EC1) significantly decreased adhesion and spreading of SMC and HUVEC. HUVECs adherent on T-cad or anti-EC1 substratum exhibited an elongated morphology and associated redistribution of the cytoskeleton and focal adhesions to a distinctly peripheral location. These changes are characteristic of the less-adhesive, motile or pro-migratory, pro-angiogenic phenotype. Boyden chamber migration assay demonstrated that the deadhesion induced by T-cad facilitates cell migration towards a serum gradient. Overexpression of T-cad in vascular cells using adenoviral vectors does not influence cell adhesion or motility per se, but increases the detachment and migratory responses induced by T-cad substratum. The data suggest that T-cad acts as an anti-adhesive signal for vascular cells, thus modulating vascular cell phenotype and migration properties.