Showing papers in "Journal of Cellular and Molecular Medicine in 2011"
TL;DR: Cellular and molecular consequences of physioxia versus normoxia and hypoxia, and the role of microRNAs in Hypoxia‐dependent regulations are summarized.
Abstract: Oxygen supply and diffusion into tissues are necessary for survival. The oxygen partial pressure (pO2), which is a key component of the physiological state of an organ, results from the balance between oxygen delivery and its consumption. In mammals, oxygen is transported by red blood cells circulating in a well-organized vasculature. Oxygen delivery is dependent on the metabolic requirements and functional status of each organ. Consequently, in a physiological condition, organ and tissue are characterized by their own unique ‘tissue normoxia’ or ‘physioxia’ status. Tissue oxygenation is severely disturbed during pathological conditions such as cancer, diabetes, coronary heart disease, stroke, etc., which are associated with decrease in pO2, i.e. ‘hypoxia’. In this review, we present an array of methods currently used for assessing tissue oxygenation. We show that hypoxia is marked during tumour development and has strong consequences for oxygenation and its influence upon chemotherapy efficiency. Then we compare this to physiological pO2 values of human organs. Finally we evaluate consequences of physioxia on cell activity and its molecular modulations. More importantly we emphasize the discrepancy between in vivo and in vitro tissue and cells oxygen status which can have detrimental effects on experimental outcome. It appears that the values corresponding to the physioxia are ranging between 11% and 1% O2 whereas current in vitro experimentations are usually performed in 19.95% O2, an artificial context as far as oxygen balance is concerned. It is important to realize that most of the experiments performed in so-called normoxia might be dangerously misleading.
962 citations
TL;DR: Decorin and growth control, and genetic evidence for a role for decorin in carcinogenesis and mechanism of decorin action: suppression of β‐catenin and Myc levels are presented.
Abstract: Proteoglycans, key molecular effectors of cell surface and pericellular microenvironments, perform multiple functions in cancer and angiogenesis by virtue of their polyhedric nature and their ability to interact with both ligands and receptors that regulate neoplastic growth and neovascularization. Some proteoglycans such as perlecan, have pro- and anti-angiogenic activities, whereas other proteoglycans, such as syndecans and glypicans, can also directly affect cancer growth by modulating key signalling pathways. The bioactivity of these proteoglycans is further modulated by several classes of enzymes within the tumour microenvironment: (i) sheddases that cleave transmembrane or cell-associated syndecans and glypicans, (ii) various proteinases that cleave the protein core of pericellular proteoglycans and (iii) heparanases and endosulfatases which modify the structure and bioactivity of various heparan sulphate proteoglycans and their bound growth factors. In contrast, some of the small leucine-rich proteoglycans, such as decorin and lumican, act as tumour repressors by physically antagonizing receptor tyrosine kinases including the epidermal growth factor and the Met receptors or integrin receptors thereby evoking anti-survival and pro-apoptotic pathways. In this review we will critically assess the expanding repertoire of molecular interactions attributed to various proteoglycans and will discuss novel proteoglycan functions modulating cancer progression, invasion and metastasis and how these factors regulate the tumour microenvironment.
461 citations
TL;DR: Embryonic, foetal and adult stem cells in osteogenesis, specific features of bone cells needed to be advantageous for clinical use, and the development of therapeutic biological agents.
Abstract: This invited review covers research areas of central importance for orthopaedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and foetal stem cells, effects of sex steroids on mesenchymal stem cells, use of platelet-rich plasma for tissue repair, osteogenesis and its molecular markers. A variety of cells in addition to stem cells, as well as advances in materials science to meet specific requirements for bone and soft tissue regeneration by addition of bioactive molecules, are discussed.
334 citations
TL;DR: The IRE1 axis: non‐conventional splicing of XBP1 mRNA and the PERK axis: attenuation of translation and the ATF6 axis: regulated proteolytic activation are studied.
Abstract: The stimuli for neuronal cell death in neurodegenerative disorders are multi-factorial and may include genetic predisposition, environmental factors, cellular stressors such as oxidative stress and free radical production, bioenergy failure, glutamate-induced excitotoxicity, neuroinflammation, disruption of Ca2+-regulating systems, mitochondrial dysfunction and misfolded protein accumulation. Cellular stress disrupts functioning of the endoplasmic reticulum (ER), a critical organelle for protein quality control, leading to induction of the unfolded protein response (UPR). ER stress may contribute to neurodegeneration in a range of neurodegenerative disorders. This review summarizes the molecular events occurring during ER stress and the unfolded protein response and it specifically evaluates the evidence suggesting the ER stress response plays a role in neurodegenerative disorders.
300 citations
TL;DR: The insulin and IGF‐1 system in AD and its role in brain amyloid formation, inflammation and AD are studied.
Abstract: Type 2 diabetes mellitus (DM) appears to be a significant risk factor for Alzheimer disease (AD). Insulin and insulin-like growth factor-1 (IGF-1) also have intense effects in the central nervous system (CNS), regulating key processes such as neuronal survival and longevity, as well as learning and memory. Hyperglycaemia induces increased peripheral utilization of insulin, resulting in reduced insulin transport into the brain. Whereas the density of brain insulin receptor decreases during age, IGF-1 receptor increases, suggesting that specific insulin-mediated signals is involved in aging and possibly in cognitive decline. Molecular mechanisms that protect CNS neurons against β-amyloid-derived-diffusible ligands (ADDL), responsible for synaptic deterioration underlying AD memory failure, have been identified. The protection mechanism does not involve simple competition between ADDLs and insulin, but rather it is signalling dependent down-regulation of ADDL-binding sites. Defective insulin signalling make neurons energy deficient and vulnerable to oxidizing or other metabolic insults and impairs synaptic plasticity. In fact, destruction of mitochondria, by oxidation of a dynamic-like transporter protein, may cause synapse loss in AD. Moreover, interaction between Aβ and τ proteins could be cause of neuronal loss. Hyperinsulinaemia as well as complete lack of insulin result in increased τ phosphorylation, leading to an imbalance of insulin-regulated τ kinases and phosphatates. However, amyloid peptides accumulation is currently seen as a key step in the pathogenesis of AD. Inflammation interacts with processing and deposit of β-amyloid. Chronic hyperinsulinemia may exacerbate inflammatory responses and increase markers of oxidative stress. In addition, insulin appears to act as ‘neuromodulator’, influencing release and reuptake of neurotransmitters, and improving learning and memory. Thus, experimental and clinical evidence show that insulin action influences cerebral functions. In this paper, we reviewed several mechanisms by which insulin may affect pathophysiology in AD.
230 citations
TL;DR: Evidence is provided on the role of metformin as an anti‐proliferative therapeutic that can act through both AM PK‐dependent as well as AMPK‐independent pathways.
Abstract: Metformin, the most widely used drug for type 2 diabetes activates 59 adenosine monophosphate (AMP)-activated protein kinase (AMPK), which regulates cellular energy metabolism. Here, we report that ovarian cell lines VOSE, A2780, CP70, C200, OV202, OVCAR3, SKOV3ip, PE01 and PE04 predominantly express -α1, -β1, -γ1 and -γ2 isoforms of AMPK subunits. Our studies show that metformin treatment (1) significantly inhibited proliferation of diverse chemo-responsive and -resistant ovarian cancer cell lines (A2780, CP70, C200, OV202, OVCAR3, SKVO3ip, PE01 and PE04), (2) caused cell cycle arrest accompanied by decreased cyclin D1 and increased p21 protein expression, (3) activated AMPK in various ovarian cancer cell lines as evident from increased phosphorylation of AMPKα and its downstream substrate; acetyl co-carboxylase (ACC) and enhanced β-oxidation of fatty acid and (4) attenuated mTOR-S6RP phosphorylation, inhibited protein translational and lipid biosynthetic pathways, thus implicating metformin as a growth inhibitor of ovarian cancer cells. We also show that metformin-mediated effect on AMPK is dependent on liver kinase B1 (LKB1) as it failed to activate AMPK-ACC pathway and cell cycle arrest in LKB1 null mouse embryo fibroblasts (mefs). This observation was further supported by using siRNA approach to down-regulate LKB1 in ovarian cancer cells. In contrast, met formin inhibited cell proliferation in both wild-type and AMPKα1/2 null mefs as well as in AMPK silenced ovarian cancer cells. Collectively, these results provide evidence on the role of metformin as an anti-proliferative therapeutic that can act through both AMPK-dependent as well as AMPK-independent pathways.
206 citations
TL;DR: The direct (physical) contact of TCs with endothelial tubes, as well as the indirect (chemical) positive influence within the ‘angiogenic zones’, suggests an important participation ofTCs in neo‐angiogenesis during the late stage of myocardial infarction.
Abstract: We used rat experimental myocardial infarction to study the ultrastructural recovery, especially neo-angiogenesis in the infarction border zone. We were interested in the possible role(s) of telocytes (TCs), a novel type of interstitial cell very recently discovered in myocardim (see http://www.telocytes.com). Electron microscopy, immunocytochemistry and analysis of several proangiogenic microRNAs provided evidence for TC involvement in neo-angiogenesis after myocardial infarction. Electron microscopy showed the close spatial association of TCs with neoangiogenetic elements. Higher resolution images provided the following information: (a) the intercellular space between the abluminal face of endothelium and its surrounding TCs is frequently less than 50 nm; (b) TCs establish multiple direct nanocontacts with endothelial cells, where the extracellular space seems obliterated; such nanocontacts have a length of 0.4–1.5 μm; (c) the absence of basal membrane on the abluminal face of endothelial cell. Besides the physical contacts (either nanoscopic or microscopic) TCs presumably contribute to neo-angiognesis via paracrine secretion (as shown by immunocytochemistry for VEGF or NOS2). Last but not least, TCs contain measurable quantities of angiogenic microRNAs (e.g. let-7e, 10a, 21, 27b, 100, 126-3p, 130a, 143, 155, 503). Taken together, the direct (physical) contact of TCs with endothelial tubes, as well as the indirect (chemical) positive influence within the ‘angiogenic zones’, suggests an important participation of TCs in neo-angiogenesis during the late stage of myocardial infarction.
185 citations
TL;DR: In culture, TCs (but not satellite cells) emerge from muscle explants and form networks suggesting a key role in muscle regeneration and repair, at least after trauma.
Abstract: Skeletal muscle interstitium is crucial for regulation of blood flow, passage of substances from capillaries to myocytes and muscle regeneration. We show here, probably, for the first time, the presence of telocytes (TCs), a peculiar type of interstitial (stromal) cells, in rat, mouse and human skeletal muscle. TC features include (as already described in other tissues) a small cell body and very long and thin cell prolongations—telopodes (Tps) with moniliform appearance, dichotomous branching and 3D-network distribution. Transmission electron microscopy (TEM) revealed close vicinity of Tps with nerve endings, capillaries, satellite cells and myocytes, suggesting a TC role in intercellular signalling (via shed vesicles or exosomes). In situ immunolabelling showed that skeletal muscle TCs express c-kit, caveolin-1 and secrete VEGF. The same phenotypic profile was demonstrated in cell cultures. These markers and TEM data differentiate TCs from both satellite cells (e.g. TCs are Pax7 negative) and fibroblasts (which are c-kit negative). We also described non-satellite (resident) progenitor cell niche. In culture, TCs (but not satellite cells) emerge from muscle explants and form networks suggesting a key role in muscle regeneration and repair, at least after trauma.
180 citations
TL;DR: In conclusion, the next generation of MMPs should be developed to address the challenges faced by the current generation of politicians and policymakers in the rapidly changing environment.
Abstract: The original notion that matrix metalloproteinases (MMPs) act as tumour and metastasis-promoting enzymes by clearing a path for tumour cells to invade and metastasize has been challenged in the last decade. It has become clear that MMPs are involved in numerous steps of tumour progression and metastasis, and hence are now considered to be multifaceted proteases. Moreover, more recent experimental evidence indicates that some members of the MMP family behave as tumour-suppressor enzymes and should therefore be regarded as anti-targets in cancer therapy. The complexity of the pro- and anti-tumorigenic and -metastatic functions might partly explain why broad-spectrum MMP inhibitors failed in phase III clinical trials. This review will provide a focussed overview of the published data on the tumour-suppressive behaviour of MMPs.
176 citations
TL;DR: The role of Gene structure and regulation in regulation, target molecules, and other biological functions in development and cancer research is studied.
Abstract: The discovery of microRNAs (miRNAs) represents one of the most significant advances in biological and medical sciences in the last decade. Hundreds of miRNAs have been identified in plants, viruses, animals and human beings, and these tiny, non-coding RNA transcripts have been found to play crucial roles in important biological processes involved in human health and disease. Recently, many studies have demonstrated that miR-196 plays critical roles in normal development and in the pathogenesis of human disease processes such as cancer. Several investigations have implemented cell culture and animal models to explore the potential molecular mechanisms of miR-196. This review provides updated information about the structure of the miR-196 gene and the roles of miR-196 in development, cancer and disease formation. Importantly, we discuss the possible molecular mechanisms whereby miR-196 regulates cellular functions including targeting molecules and gene regulation pathways; potential clinical applications are addressed, as well as future directions for investigation. miR-196a may prove to be a novel therapeutic target for several cancers.
176 citations
TL;DR: It is found that both L and D‐CAR greatly reduced obese‐related diseases in obese Zucker rat, by significantly restraining the development of dyslipidaemia, hypertension and renal injury, as demonstrated by both urinary parameters and electron microscopy examinations of renal tissue.
Abstract: The metabolic syndrome is a risk factor that increases the risk for development of renal and vascular complications. This study addresses the effects of chronic administration of the endogenous dipeptide carnosine (β-alanyl-L-histidine, L-CAR) and of its enantiomer (β-alanyl-D-histidine, D-CAR) on hyperlipidaemia, hypertension, advanced glycation end products, advanced lipoxidation end products formation and development of nephropathy in the non-diabetic, Zucker obese rat. The Zucker rats received a daily dose of L-CAR or D-CAR (30 mg/kg in drinking water) for 24 weeks. Systolic blood pressure was recorded monthly. At the end of the treatment, plasma levels of triglycerides, total cholesterol, glucose, insulin, creatinine and urinary levels of total protein, albumin and creatinine were measured. Several indices of oxidative/carbonyl stress were also measured in plasma, urine and renal tissue. We found that both L- and D-CAR greatly reduced obese-related diseases in obese Zucker rat, by significantly restraining the development of dyslipidaemia, hypertension and renal injury, as demonstrated by both urinary parameters and electron microscopy examinations of renal tissue. Because the protective effect elicited by L- and D-CAR was almost superimposable, we conclude that the pharmacological action of L-CAR is not due to a pro-histaminic effect (D-CAR is not a precursor of histidine, since it is stable to peptidic hydrolysis), and prompted us to propose that some of the biological effects can be mediated by a direct carbonyl quenching mechanism.
TL;DR: HEDSC are a highly inducible source of allogenic stem cells that rescue dopamine concentrations in an immunocompetent PD mouse model and significantly increase striatal dopamine and dopamine metabolite concentrations.
Abstract: Parkinson’s disease (PD) is a neurodegenerative disorder caused by the loss of dopaminergic neurons. Adult human endometrial derived stem cells (HEDSC), a readily obtainable type of mesenchymal stem-like cell, were used to generate dopaminergic cells and for transplantation. Cells expressing CD90, platelet derived growth factor (PDGF)-Rβ and CD146 but not CD45 or CD31 were differentiated in vitro into dopaminergic neurons that exhibited axon projections, pyramidal cell bodies and dendritic projections that recapitulate synapse formation; these cells also expressed the neural marker nestin and tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis. Whole cell patch clamp recording identified G-protein coupled inwardly rectifying potassium current 2 channels characteristic of central neurons. A 1-methyl 4-phenyl 1,2,3,6-tetrahydro pyridine induced animal model of PD was used to demonstrate the ability of labelled HEDSC to engraft, migrate to the site of lesion, differentiate in vivo and significantly increase striatal dopamine and dopamine metabolite concentrations. HEDSC are a highly inducible source of allogenic stem cells that rescue dopamine concentrations in an immunocompetent PD mouse model.
TL;DR: Investigation of the expression of miRNAs in three leukaemia cell lines with different degrees of resistance to doxorubicin compared with their parent cell line resulted in the increased sensitivity of cells to DOX, suggesting that correction of altered expression ofmiRNAs may be used for therapeutic strategies to overcome leukaemic cell resistance.
Abstract: Multidrug resistance (MDR) and disease relapse are challenging clinical problems in the treatment of leukaemia. Relapsed disease is frequently refractory to chemotherapy and exhibits multiple drug resistance. Therefore, it is important to identify the mechanism by which cancer cells develop resistance. In this study, we used microRNA (miRNA) microarray and qRT-PCR approaches to investigate the expression of miRNAs in three leukaemia cell lines with different degrees of resistance to doxorubicin (DOX) compared with their parent cell line, K562. The expression of miR-331–5p and miR-27a was inversely correlated with the expression of a drug-resistant factor, P-glycoprotein (P-gp), in leukaemia cell lines with gradually increasing resistance. The development of drug resistance is regulated by the expression of the P-gp. Transfection of the K562 and, a human promyelocytic cell line (HL) HL60 DOX-resistant cells with miR-331–5p and miR-27a, separately or in combination, resulted in the increased sensitivity of cells to DOX, suggesting that correction of altered expression of miRNAs may be used for therapeutic strategies to overcome leukaemia cell resistance. Importantly, miR-331–5p and miR-27a were also expressed at lower levels in a panel of relapse patients compared with primary patients at diagnosis, further illustrating that leukaemia relapse might be a consequence of deregulation of miR-331–5p and miR-27a.
TL;DR: This study demonstrates that in the cardiomyocytes clones differentiated from HFF‐derived iPS, the functional properties related to excitation–contraction coupling, resemble in part those of adult card iomyocytes.
Abstract: In view of the therapeutic potential of cardiomyocytes derived from induced pluripotent stem (iPS) cells (iPS-derived cardiomyocytes), in the present study we investigated in iPS-derived cardiomyocytes, the functional properties related to [Ca2+]i handling and contraction, the contribution of the sarcoplasmic reticulum (SR) Ca2+ release to contraction and the b-adrenergic inotropic responsiveness. The two iPS clones investigated here were generated through infection of human foreskin fibroblasts (HFF) with retroviruses containing the four human genes: OCT4, Sox2, Klf4 and C-Myc. Our major findings showed that iPS-derived cardiomyocytes: (i) express cardiac specific RNA and proteins; (ii) exhibit negative force–frequency relations and mild (compared to adult) post-rest potentiation; (iii) respond to ryanodine and caffeine, albeit less than adult cardiomyocytes, and express the SR-Ca2+ handling proteins ryanodine receptor and calsequestrin. Hence, this study demonstrates that in our cardiomyocytes clones differentiated from HFF-derived iPS, the functional properties related to excitation–contraction coupling, resemble in part those of adult cardiomyocytes.
TL;DR: iPSC and hESC differentiate into cardiomyocytes of comparable ultrastructure, thus supporting the notion that iPSC offer a viable option for an autologous cell source for cardiac regenerative therapy.
Abstract: Induced pluripotent stem cells (iPSC) are generated from fully differentiated somatic cells that were reprogrammed into a pluripotent state. Human iPSC which can be obtained from various types of somatic cells such as fibroblasts or keratinocytes can differentiate into cardiomyocytes (iPSC-CM), which exhibit cardiac-like transmembrane action potentials, intracellular Ca2+ transients and contractions. While major features of the excitation-contraction coupling of iPSC-CM have been well-described, very little is known on the ultrastructure of these cardiomyocytes. The ultrastructural features of 31-day-old (post-plating) iPSC-CM generated from human hair follicle keratinocytes (HFKT-iPSC-CM) were analysed by electron microscopy, and compared with those of human embryonic stem-cell-derived cardiomyocytes (hESC-CM). The comparison showed that cardiomyocytes from the two sources share similar proprieties. Specifically, HFKT-iPSC-CM and hESC-CM, displayed ultrastructural features of early and immature phenotype: myofibrils with sarcomeric pattern, large glycogen deposits, lipid droplets, long and slender mitochondria, free ribosomes, rough endoplasmic reticulum, sarcoplasmic reticulum and caveolae. Noteworthy, the SR is less developed in HFKT-iPSC-CM. We also found in both cell types: (1) ‘Ca2+-release units’, which connect the peripheral sarcoplasmic reticulum with plasmalemma; and (2) intercellular junctions, which mimic intercalated disks (desmosomes and fascia adherens). In conclusion, iPSC and hESC differentiate into cardiomyocytes of comparable ultrastructure, thus supporting the notion that iPSC offer a viable option for an autologous cell source for cardiac regenerative therapy.
TL;DR: This chapter discusses the pathways and consequences of intercellular protein transfer between the cells of immune system and systems unrelated to immunity, and the role of TCR‐mediated internalization and recycling in this phenomenon.
Abstract: In a multicellular system, cellular communication is a must for orchestration and coordination of cellular events. Advent of the latest analytical and imaging tools has allowed us to enhance our understanding of the intercellular communication. An intercellular exchange of proteins or intact membrane patches is a ubiquitous phenomenon, and has been the subject of renewed interest, particularly in the context of immune cells. Recent evidence implicates that intercellular protein transfers, including trogocytosis is an important mechanism of the immune system to modulate immune responses and transferred proteins can also contribute to pathology. It has been demonstrated that intercellular protein transfer can be through the internalization/pathway, dissociation-associated pathway, uptake of exosomes and membrane nanotube formations. Exchange of membrane molecules/antigens between immune cells has been observed for a long time, but the mechanisms and functional consequences of these transfers remain unclear. In this review, we will discuss the important findings concerning intercellular protein transfers, possible mechanisms and highlight their physiological relevance to the immune system, with special reference to T cells such as the stimulatory or suppressive immune responses derived from T cells with acquired dendritic cell membrane molecules.
TL;DR: It is shown that TAFs and MSCs share immunophenotypic similarities, including the presence of certain cell surface molecules, and production of cytokines, chemokines and growth factors showed a significant increase in T AFs for vascular endothelial growth factor, transforming growth factor‐β1, interleukins and tumour necrosis factors.
Abstract: Tumour-associated fibroblasts (TAFs) are part of the tumour stroma, providing functional and structural support for tumour progression and development. The origin and biology of TAFs are poorly understood, but within the tumour environment, TAFs become activated and secrete different paracrine and autocrine factors involved in tumorigenesis. It has been shown that bone marrow mesenchymal stem cells (MSCs) can be recruited into the tumours, where they proliferate and acquire a TAF-like phenotype. We attempted to determine to what extent TAFs characteristics in vitro juxtapose to MSCs’ definition, and we showed that TAFs and MSCs share immunophenotypic similarities, including the presence of certain cell surface molecules [human leukocyte antigen-DR subregion (HLA-DR), CD29, CD44, CD73, CD90, CD106 and CD117]; the expression of cytoskeleton and extracellular matrix proteins, such as vimentin, α-smooth muscle actin, nestin and trilineage differentiation potential (to adipocytes, chondrocytes and osteoblasts). When compared to MSCs, production of cytokines, chemokines and growth factors showed a significant increase in TAFs for vascular endothelial growth factor, transforming growth factor-β1, interleukins (IL-4, IL-10) and tumour necrosis factor α. Proliferation rate was highly increased in TAFs and fibroblast cell lines used in our study, compared to MSCs, whereas ultrastructural details differentiated the two cell types by the presence of cytoplasmic elongations, lamellar content lysosomes and intermediate filaments. Our results provide supportive evidence to the fact that TAFs derive from MSCs and could be a subset of ‘specialized’ MSCs.
TL;DR: It is shown that cardiac remodelling induced by paracrine effects and other potential effects including anti‐inflammatory effect of MSCs and anti‐apoptotic effects by M SCs are related.
Abstract: The prognosis of patients with myocardial infarction (MI) and resultant chronic heart failure remains extremely poor despite advances in optimal medical therapy and interventional procedures. Animal experiments and clinical trials using adult stem cell therapy following MI have shown a global improvement of myocardial function. Bone marrow-derived mesenchymal stem cells (MSCs) hold promise for cardiac repair following MI, due to their multilineage, self-renewal and proliferation potential. In addition, MSCs can be easily isolated, expanded in culture, and have immunoprivileged properties to the host tissue. Experimental studies and clinical trials have revealed that MSCs not only differentiate into cardiomyocytes and vascular cells, but also secrete amounts of growth factors and cytokines which may mediate endogenous regeneration via activation of resident cardiac stem cells and other stem cells, as well as induce neovascularization, anti-inflammation, anti-apoptosis, anti-remodelling and cardiac contractility in a paracrine manner. It has also been postulated that the anti-arrhythmic and cardiac nerve sprouting potential of MSCs may contribute to their beneficial effects in cardiac repair. Most molecular and cellular mechanisms involved in the MSC-based therapy after MI are still unclear at present. This article reviews the potential repair mechanisms of MSCs in the setting of MI.
TL;DR: Whether hypoxic stimulation triggers MIF secretion from ECs and whether the MIF/CXCR4 axis contributes to EPC recruitment is studied and MIF potently promoted EPC chemotaxis in a dose‐dependent bell‐shaped manner is studied.
Abstract: Macrophage migration inhibitory factor (MIF) is a pleiotropic inflammatory cytokine that was recently identified as a non-cognate ligand of the CXC-family chemokine receptors 2 and 4 (CXCR2 and CXCR4). MIF is expressed and secreted from endothelial cells (ECs) following atherogenic stimulation, exhibits chemokine-like properties and promotes the recruitment of leucocytes to atherogenic endothelium. CXCR4 expressed on endothelial progenitor cells (EPCs) and EC-derived CXCL12, the cognate ligand of CXCR4, have been demonstrated to be critical when EPCs are recruited to ischemic tissues. Here we studied whether hypoxic stimulation triggers MIF secretion from ECs and whether the MIF/CXCR4 axis contributes to EPC recruitment. Exposure of human umbilical vein endothelial cells (HUVECs) and human aortic endothelial cells (HAoECs) to 1% hypoxia led to the specific release of substantial amounts of MIF. Hypoxia-induced MIF release followed a biphasic behaviour. MIF secretion in the first phase peaked at 60 min. and was inhibited by glyburide, indicating that this MIF pool was secreted by a non-classical mechanism and originated from pre-formed MIF stores. Early hypoxia-triggered MIF secretion was not inhibited by cycloheximide and echinomycin, inhibitors of general and hypoxia-inducible factor (HIF)-1α-induced protein synthesis, respectively. A second phase of MIF secretion peaked around 8 hrs and was likely due to HIF-1α-induced de novo synthesis of MIF. To functionally investigate the role of hypoxia-inducible secreted MIF on the recruitment of EPCs, we subjected human AcLDL+ KDR+ CD31+ EPCs to a chemotactic MIF gradient. MIF potently promoted EPC chemotaxis in a dose-dependent bell-shaped manner (peak: 10 ng/ml MIF). Importantly, EPC migration was induced by supernatants of hypoxia-conditioned HUVECs, an effect that was completely abrogated by anti-MIF- or anti-CXCR4-antibodies. Thus, hypoxia-induced MIF secretion from ECs might play an important role in the recruitment and migration of EPCs to hypoxic tissues such as after ischemia-induced myocardial damage.
TL;DR: The present study focuses on the characterization of cells for bone regeneration in human beings and the applications of cell based therapies for bone repair in paediatric bone disorders and cellular therapies.
Abstract: Regenerative medicine seeks to repair or replace damaged tissues or organs, with the goal to fully restore structure and function without the formation of scar tissue. Cell based therapies are promising new therapeutic approaches in regenerative medicine. By using mesenchymal stem cells, good results have been reported for bone engineering in a number of clinical studies, most of them investigator initiated trials with limited scope with respect to controls and outcome. With the implementation of a new regulatory framework for advanced therapeutic medicinal products, the stage is set to improve both the characterization of the cells and combination products, and pave the way for improved controlled and well-designed clinical trials. The incorporation of more personalized medicine approaches, including the use of biomarkers to identify the proper patients and the responders to treatment, will be contributing to progress in the field. Both translational and clinical research will move the boundaries in the field of regenerative medicine, and a coordinated effort will provide the clinical breakthroughs, particularly in the many applications of bone engineering.
TL;DR: It is demonstrated for the first time that MSCs survive exposure to long‐term (12 days), severe (pO2 < 1.5 mmHg) hypoxia, provided glucose is available and the traditional view according to which severe Hypoxia per se is responsible for the massive MSC death observed upon transplantation is challenged.
Abstract: Use of mesenchymal stem cells (MSCs) has emerged as a potential new treatment for various diseases but has generated marginally successful results. A consistent finding of most studies is massive death of transplanted cells. The present study examined the respective roles of glucose and continuous severe hypoxia on MSC viability and function with respect to bone tissue engineering. We hereby demonstrate for the first time that MSCs survive exposure to long-term (12 days), severe (pO2 < 1.5 mmHg) hypoxia, provided glucose is available. To this end, an in vitro model that mimics the hypoxic environment and cell-driven metabolic changes encountered by grafted sheep cells was established. In this model, the hallmarks of hypoxia (low pO2, hypoxia inducible factor-1α expression and anaerobic metabolism) were present. When conditions switched from hypoxic (low pO2) to ischemic (low pO2 and glucose depletion), MSCs exhibited shrinking, decreased cell viability and ATP content due to complete exhaustion of glucose at day 6; these results provided evidence that ischemia led to the observed massive cell death. Moreover, MSCs exposed to severe, continuous hypoxia, but without any glucose shortage, remained viable and maintained both their in vitro proliferative ability after simulation with blood reperfusion at day 12 and their in vivo osteogenic ability. These findings challenge the traditional view according to which severe hypoxia per se is responsible for the massive MSC death observed upon transplantation of these cells and provide evidence that MSCs are able to withstand exposure to severe, continuous hypoxia provided that a glucose supply is available.
TL;DR: Close correlation was found between the surface charge on an aging RBC and its structure and functions, from the cell morphology, the membrane deformability to the intracellular Hb structure and oxidation ability.
Abstract: Red blood cells (RBCs) during microcirculation, aging and storage, lose N-acetylneuraminic acid (NANA) and other biomaterials thereby altering cell structures, some properties and functions Such cell damage very likely underlies the serious adverse effects of blood transfusion However, a controversy has remained since 1961–1977 as to whether with aging, the RBCs, suffering loss of NANA, do have a decreased charge density Any correlation between the changes in the cell properties with cell aging is also not clear Therefore, to remove the ambiguity and uncertainty, we carried out multiparameteric studies on Percoll fractions of blood of 38 volunteers (lightest-young-Y-RBCs, densest-old-O-RBCs, two middle fractions)We found that there were striking differences between the properties of Y-RBCs and O-RBCs The ζ-potential of Y-RBCs decreased gradually with aging Studies in parallel on RBC fractions incubated with both positively charged quantum dots and Sambucus Nigra-fluorescein isothiocyanate (FITC) along with their ζ-potentials provide for the first time direct visual evidence about the lesser amount of charge density and NANA on O-RBCs, and a collinear decrease in their respective ζ-potentials Close correlation was found between the surface charge on an aging RBC and its structure and functions, from the cell morphology, the membrane deformability to the intracellular Hb structure and oxidation ability This quantitative approach not only clarifies the picture but also has implications in biology and medicine
TL;DR: It is indicated that Twist1 induces HCC invasion via increased activity in MMPs, leading to poor clinical prognoses, and a novel cogitation in Twist2, which has no effect on H CC invasion and metastasis.
Abstract: E-cadherin loss is a key biological mechanism in tumour invasion. As a main regulator of epithelial-mesenchymal transition (EMT) mechanism-mediated invasion and metastasis, Twist1 plays an important role through its regulation of E-cadherin expression. However, whether or not Twist2 has the same function in tumour metastasis remains unclear. The purpose of this study is to investigate the expressions and different roles of Twist1 and Twist2 in human hepatocellular carcinoma (HCC). The expressions of Twist1 and Twist2 in HCC tissue were evaluated by immunohistochemical staining. The role of Twist1 and Twist2 in invasiveness was also evaluated in vitro by using HCC cell lines. Twist1 nuclear overexpression is found to be correlated with HCC metastasis, and its expression is negatively correlated with E-cadherin expression in human tissue. Twist2, a Twist1 homology protein, only expresses in the cytoplasm and shows no significant correlation with HCC metastasis. By ectopic transfection of Twist1 and Twist2 into the HCC cells, HepG2 and PLC, Twist1 is able to down-regulate E-cadherin expression and promote matrix metalloproteinase (MMP) activation, specifically in MMP2 and MMP9. In functional assays, Twist1 is found to promote invasion in HepG2 and PLC cells, but the invasion ability of the groups is not affected Twist2. Our findings indicate that Twist1 induces HCC invasion via increased activity in MMPs, leading to poor clinical prognoses. The results of this study also demonstrate a novel cogitation in Twist2, which has no effect on HCC invasion and metastasis. Twist1 may contribute to HCC invasion and metastasis and may be used as a novel therapeutic target for the inhibition of HCC metastasis.
TL;DR: MiR‐155 provides the opportunity to block necrosis, a conventionally thought non‐regulated process, and might be a potential novel approach to improve cell engraftment for cell therapy.
Abstract: To improve regeneration of the injured myocardium, cardiomyocyte progenitor cells (CMPCs) have been put forward as a potential cell source for transplantation therapy. Although cell transplantation therapy displayed promising results, many issues need to be addressed before fully appreciating their impact. One of the hurdles is poor graft-cell survival upon injection, thereby limiting potential beneficial effects. Here, we attempt to improve CMPCs survival by increasing microRNA-155 (miR-155) levels, potentially to improve engraftment upon transplantation. Using quantitative PCR, we observed a 4-fold increase of miR-155 when CMPCs were exposed to hydrogen-peroxide stimulation. Flow cytometric analysis of cell viability, apoptosis and necrosis showed that necrosis is the main cause of cell death. Overexpressing miR-155 in CMPCs revealed that miR-155 attenuated necrotic cell death by 40 ± 2.3%via targeting receptor interacting protein 1 (RIP1). In addition, inhibiting RIP1, either by pre-incubating the cells with a RIP1 specific inhibitor, Necrostatin-1 or siRNA mediated knockdown, reduced necrosis by 38 ± 2.5% and 33 ± 1.9%, respectively. Interestingly, analysing gene expression using a PCR-array showed that increased miR-155 levels did not change cell survival and apoptotic related gene expression. By targeting RIP1, miR-155 repressed necrotic cell death of CMPCs, independent of activation of Akt pro-survival pathway. MiR-155 provides the opportunity to block necrosis, a conventionally thought non-regulated process, and might be a potential novel approach to improve cell engraftment for cell therapy.
TL;DR: Defining autoantibody signatures in cancer: still many challenges and how to build screening tests in high‐risk populations is explored.
Abstract: Becoming invasive is a crucial step in cancer development, and the early spread of tumour cells is usually undetected by current imaging technologies. In patients with cancer and no signs of overt metastases, sensitive methods have been developed to identify circulating autoantibodies and their antigen counterparts in several cancers. These technologies are often based on proteomic approaches, and recent advances in protein and antibody microarrays have greatly facilitated the discovery of new antibody biomarkers in sera from cancer patients. Interestingly, in a clinical application setting, combinations of multiple autoantibody reactivities into panel assays have recently been proposed as relevant screening tests and validated in several independent trials. In addition, autoantibody signatures seem to be particularly relevant for early detection of cancer in high-risk cancer patients. In this review, we highlight the concept that immunogenic epitopes associated with the humoural response and key pathogenic pathways elicit serum autoantibodies that can be considered as relevant cancer biomarkers. We outline the proteomic strategies employed to identify and validate their use in clinical practice for cancer screening and diagnosis. We particularly emphasize the clinical utility of autoantibody signatures in several cancers. Finally, we discuss the challenges remaining for clinical validation.
TL;DR: This work shows that PDT prompted Akt‐mTOR (mammalian target of rapamycin) pathway down‐regulation and stimulated macroautophagy (MA) in cancer and normal cells and unravels CMA as the dominant defence mechanism against PDT.
Abstract: Reactive oxygen species (ROS) concurrently instigate apoptosis and autophagy pathways, but the link between these processes remains unclear. Because cytotoxic ROS formation is exploited in anticancer therapy, such as in photodynamic therapy (PDT), a better understanding of the complex interplay between autophagy and apoptosis is urgently required. Previously, we reported that ROS generated by PDT with an endoplasmic reticulum (ER)-associated sensitizer leads to loss of ER-Ca2+ homeostasis, ER stress and apoptosis. Here we show that PDT prompted Akt-mTOR (mammalian target of rapamycin) pathway down-regulation and stimulated macroautophagy (MA) in cancer and normal cells. Overexpression of the antioxidant enzyme glutathione peroxidase-4 reversed mTOR down-regulation and blocked MA progression and apoptosis. Attenuating MA using Atg5 knockdown or 3-methyladenine, reduced clearance of oxidatively damaged proteins and increased apoptosis, thus revealing a cytoprotective role of MA in PDT. Paradoxically, genetic loss of MA improved clearance of oxidized proteins and reduced photokilling. We found that up-regulation of chaperone-mediated autophagy (CMA) in unstressed Atg5−/− cells compensated for MA loss and increased cellular resistance to PDT. CMA-deficient cells were significantly sensitized to photokilling but were protected against the ER stressor thapsigargin. These results disclose a stress-specific recruitment of autophagy pathways with cytoprotective function and unravel CMA as the dominant defence mechanism against PDT.
TL;DR: The findings show that typical telocytes are present in the rat duodenum, and suggest that these cells may be involved in immune response and it may be possible that different locations of telocytes could be associated with different roles.
Abstract: Recently the new term ‘telocytes’ has been proposed for cells formerly known as interstitial Cajal-like cells. In fact, telocytes are not really Cajal-like cells, they being different from all other interstitial cells by the presence of telopodes, which are cell-body prolongations, very thin, extremely long with a moniliform aspect. The identification of these cells is based on ultrastructural criteria. The presence of telocytes in others organs was previously documented. We reported for the first time, an ultrastructural study of telocytes in the lamina propria of rat duodenum. Our findings show that typical telocytes are present in the rat duodenum. Telocytes are located in the lamina propria, immediately below mucosal crypts. Telopodes frequently establish close spatial relationships with immune cells, blood vessels and nerve endings. On the basis of their distribution and morphology, we suggest that these cells may be involved in immune response and in our opinion, it may be possible that different locations of telocytes could be associated with different roles.
TL;DR: The presence of mesenchymal markers on CTC more accurately predicted worse prognosis than the expression of cytokeratins alone and assays targeting epithelial antigens may miss the most invasive cell population.
Abstract: Circulating tumour cells (CTCs) are independent predictor of prognosis in metastatic breast cancer. Nevertheless, in one third of patients, circulating tumour cells are undetected by conventional methods. Aim of the study was to assess the prognostic value of circulating tumour cells expressing mesenchymal markers in metastatic breast cancer patients. We isolated CTC from blood of 55 metastatic breast cancer patients. CTC were characterized for cytokeratins and markers of epithelial mesenchymal transition. The gain of mesenchymal markers in CTC was correlated to prognosis of patients in a follow-up of 24 months. The presence of mesenchymal markers on CTC more accurately predicted worse prognosis than the expression of cytokeratins alone. Because of the frequent loss of epithelial antigens by CTC, assays targeting epithelial antigens may miss the most invasive cell population. Thus, there is an urgent need to improve detection methods to identify CTC which undergone epithelial mesenchymal transition program.
TL;DR: It is found that miR‐193 is differentially expressed between TCs and other interstitial cells, and this data support the previous finding that TCs express c‐kit in certain circumstances.
Abstract: Telocytes (TCs) are a particular type of interstitial (stromal) cells defined by very long, moniliform telopodes. Their tissue location, between blood vessels and other cells such as cardiomyocytes (CMC) and neurons, suggests a role in intercellular signalling. In order to define a microRNA (miR) signature in cardiac TCs, we have found that miR-193 is differentially expressed between TCs and other interstitial cells. Because miR-193 regulates c-kit, our data support the previous finding that TCs express c-kit in certain circumstances. In addition, the miRs which are specific to CMC and other muscle cells (e.g. miR-133a, miR-208a) are absent in TCs. Overall the data reinforce the view that TCs are a particular type of interstitial (mesenchymal) cells.
TL;DR: These data are the first to document different miRNA expression and regulation profiles in primary and metastatic OC, suggesting a role for these molecules in tumour progression.
Abstract: MicroRNAs (miRNAs) are small non-coding RNAs that exert a regulatory effect post-transcriptionally by binding target mRNAs and inhibiting gene translation. miRNA expression is deregulated in cancer. The aim of this study was to characterize the differences in miRNA expression pattern and the miRNA-regulating machinery between ovarian carcinoma (OC) cells in primary tumours versus effusions. Using miRNA array platforms, we analysed a set of 21 tumours (13 effusions, 8 primary carcinomas) and identified three sets of miRNAs, one that is highly expressed in both primary carcinomas and effusions, one overexpressed in primary carcinomas and one overexpressed in effusions. Levels of selected miRNAs were analysed using quantitative PCR in an independent set of 45 additional tumours (30 effusions, 15 primary carcinomas). Reduced miR-145 and miR-214 and elevated let-7f, miR-182, miR-210, miR-200c, miR-222 and miR-23a levels were found in effusions in both sets. In silico target prediction programs identified potential target genes for some of the differentially expressed miRNAs. Expression of zinc finger E-box binding homeobox (ZEB)1 and c-Myc, targets of miR-200c, as well as of p21 protein (Cdc42/Rac)-activated kinase (PAK)1 and phosphatase and tensin homologue deleted on chromosome 10 (PTEN), predicted targets of miR-222, were analysed. Inverse correlations between expression levels of the indicated miRNAs and of the predicted target genes were found. In addition, higher expression of the miRNA-processing molecules Ago1, Ago2 and Dicer was observed in effusions compared to primary carcinomas. In conclusion, our data are the first to document different miRNA expression and regulation profiles in primary and metastatic OC, suggesting a role for these molecules in tumour progression.