Endothelial Cell-Matrix Interactions

Fibrogenesis & Tissue Repair, 2012

In the last decade there have been multiple studies concerning the contribution of endothelial progenitor cells (EPCs) to new vessel formation in different physiological and pathological settings. The process by which EPCs contribute to new vessel formation in adults is termed postnatal vasculogenesis and occurs via four inter-related steps. They must respond to chemoattractant signals and mobilize from the bone marrow to the peripheral blood; home in on sites of new vessel formation; invade and migrate at the same sites; and differentiate into mature endothelial cells (ECs) and/or regulate pre-existing ECs via paracrine or juxtacrine signals. During these four steps, EPCs interact with different physiological compartments, namely bone marrow, peripheral blood, blood vessels and homing tissues. The success of each step depends on the ability of EPCs to interact, adapt and respond to multiple molecular cues. The present review summarizes the interactions between integrins expressed by EPCs and their ligands: extracellular matrix components and cell surface proteins present at sites of postnatal vasculogenesis. The data summarized here indicate that integrins represent a major molecular determinant of EPC function, with different integrin subunits regulating different steps of EPC biology. Specifically, integrin α4β1 is a key regulator of EPC retention and/or mobilization from the bone marrow, while integrins α5β1, α6β1, αvβ3 and αvβ5 are major determinants of EPC homing, invasion, differentiation and paracrine factor production. β2 integrins are the major regulators of EPC transendothelial migration. The relevance of integrins in EPC biology is also demonstrated by many studies that use extracellular matrix-based scaffolds as a clinical tool to improve the vasculogenic functions of EPCs. We propose that targeted and tissue-specific manipulation of EPC integrin-mediated interactions may be crucial to further improve the usage of this cell population as a relevant clinical agent.

Cardiovascular Research, 2008

During angiogenic remodelling in embryo and adult life, endothelial cells lining blood vessel walls dynamically modify their integrin-mediated adhesive contacts with the surrounding extracellular matrix. However, besides regulating cell adhesion and migration, integrins dynamically participate in a network with soluble molecules and their receptors. Angiogenesis is characterized by opposing autocrine and paracrine loops of growth factors and semaphorins that regulate the activation of integrins on the endothelial surface through tyrosine kinase receptors (TKR) and the neuropilin/plexin system. Moreover, pro-and anti-angiogenic factors can directly bind integrins and regulate endothelial cell behaviour. This review summarizes the recent progress in understanding the reciprocal interactions between integrins, TKR, and semaphorin receptors.

Arteriosclerosis Thrombosis and Vascular Biology, 2008

http://atvb.ahajournals.org located on the World Wide Web at:

Experimental Cell Research, 2006

From an evolutionary point of view, the development of a cardiovascular system allowed vertebrates to nourish the several organs that compose their wider multicellular organism and to survive. Acquisition of new genes encoding for extracellular matrix (ECM) proteins and their cognate integrin receptors as well as secreted pro-and anti-angiogenic factors proved to be essential for the development of vascular networks in the vertebrate embryo. Postnatal tissue neo-vascularization plays a key role during wound healing and pathological angiogenesis as well. There is now clear evidence that building blood vessels in the embryo and in the adult organism relies upon different endothelial integrins and ECM ligands. A successful vascular development depends on fibronectin and its major receptor a5h1 integrin, but not on avh3, avh5, and a6h4 integrins that are instead central regulators of postnatal tumor angiogenesis. Here, endothelial avh3 elicits anti-or pro-angiogenic signals depending respectively on whether it is occupied by a soluble (e.g. type IV collagen derived tumstatin) or an insoluble (vitronectin) ECM ligand. The laminin-5 receptor a6h4 integrin, expressed only by endothelial cells of mature blood vessels, controls the invasive phase of tumor angiogenesis in the adult organism. Finally, regulation of vascular morphogenesis relies upon the fine modulation of integrin activation by chemoattractant and chemorepulsive cues, such as angiogenic growth factors and semaphorins. D

Contrary to what the casual reader might think, God the Father is the Person of Divinity that the revelation deals with the least. We have evidently more information about the characteristics of the Son and even of the Holy Spirit as we shall see in due course. I am referring to the biblical evidence, which is actually the only one that is valuable for a Bible study in this important matter. Obviously, much has been written about the Father and his place in the Trinity, but very rarely have these writings been based on what the Word of God holds. We have studied much of this in the treatise “The Godhead", as well as the characteristics common to the 3 Persons of the Godhead. However, even though the amount of biblical information is relatively scarce (compared to the other Persons of the Godhead), what these few verses convey is a treasure that could be written about in countless treatises of varying depth. One of the most outstanding aspects, which since almost the beginning of the Christian era has created controversy, is the relationship between the Father and the Son, as well as between them and the Holy Spirit. We will try in this treatise to determine what the Holy Bible says about God the Father and we will deal with the relationships with the other Persons of the Godhead in the following treatises.

Southeast European and Black Sea Studies, 2024

The impact of the Ukraine war on EU member states’ foreign policy and civil society, given the Union’s severe measures against Russia, requires rigorous academic attention. Cyprus is a special case because of its multifaceted ties with Russia, which have been mainly developed upon three pillars: economic, diplomatic, and cultural/religious. Since 2018, systemic developments stemming from Western reaction to the annexation of Crimea have undermined Cypriot-Russian economic relations, but diplomatic and cultural ties remained strong. However, the 2022 invasion seems to have affected even the most solid pillars of Cypriot-Russian friendship. To test this hypothesis, this article examines the consequences of the war at three levels: systemic effects that relate to geopolitical developments in the Eastern Mediterranean and the renewed great power competition; Cyprus’ policy in the Council of the EU; and internal balances in the Greek Orthodox Church of Cyprus.

Zeitschrift fur Personalforschung, 2004

The model of transformational leadership, proposed by Bass (1985), has been widely used in the United States in applied research as well as in practice for more than twenty years. In Germany, as well, this approach has received increasing attention since the late nineties. This article aims to offer a rough introduction to the model proposed by Bass and to provide a general survey on recent German research dealing with this paradigm. First of all, the transferability of the concept to Germany will be discussed. Similarities with results obtained in America are shown and differences thoroughly conferred. Although some limitations and restrictions have to be considered, it can be shown that the concept of transformational leadership is a fruitful approach for leadership research in Germany. Moreover, interesting implications for managerial practice are derived. Furthermore, advanced research questions concerning antecedences and consequences of transformational leadership in Germany are examined. Furthermore, recent findings show that the self-rater version of the MLQ provides additional information concerning the quality of leadership. A detailed look is taken at the relation between leadership and different facets of commitment. It could be shown that there are significant contributions of transformational leadership to affective and normative commitment. Interesting differences appear, if one considers the different contexts. Another direction of current research focuses on the role of followers for the perception and maintenance of transformational leadership. Results indicate that followers' characteristics, such as personality traits and implicit leadership theories, influence the perception and acceptance of transformational leadership.

G.S.Leite, I.W.Sarlet y M.Carbonell, Direitos, deveres e garantias fundamentais, Ius Podium, Salvador, Bahia, Brasil, 2011

En este ensayo se examina la renovación de los criterios y estándares constitucionales contemporáneos, a partir de la regulación fundamental argentina más reciente y su aplicación jurisprudencial en materia de derecho ambiental.

A research study on the impact of information was undertaken using case studies of three rural information communities in Tanzania and Malawi. The process of information provision had two aspects. the first was direct information provision using extension workers, health workers, community notice boards and video shows. The factors which influenced both positive and negative impact are discussed in this paper. The study was funded by IDR of Canada through the Nairobi Office.