Browsing by Subject "Integrin"

Now showing 1 - 5 of 5
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    Expression of integrin αvβ3 in pig, dog and cattle
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2001) Singh, B.; Rawlings, N.; Kaur, A.
    The avlB integrin, also known as vitronectin receptor, is an adhesive glycoprotein that promotes angiogenesis in the embryo and tumors such as melanoma. Integrin avID is one of the receptors for adenovirus and hantavirus. There is little information on the constitutive expression of this integrin especially in animal species that are used for biomedical research. We used light and elec tron microscope immunocytochemistry and western blots to determine integrin avB3 expression in seven organs in the pig, dog and cattle. Immunohistology showed the integrin expression on the epithelium of small intestine , bile duct and renal proximal convoluted tubules in three species. The airway epithelium revealed a weak reaction for integrin avB3. Skin showed the integrin in occasional extravascular cells while skeletal muscles were negative. The integrin was expressed only in bronchial vasculature in the lung and occasional dermal microvessels. Many mononuclear cells in the lung and spleen stained for integrin avB3. Immunogold electron microscopy revealed the expression on the epithelium but not on the vasculature of the small intestine. Western blots detected integrin avB3 in small intestine and lung but not in skeletal muscles. We conclude the integrin is expressed on the epithelium but not in the vasculature. The expression differs strikingly among organs in the same pecies although the inter-species differences are minor. Restriction of the integrin to absorptive epithelia of small intestine and kidney may suggest its putative role in endocytosis. Because the integrin is a receptor for adenovirus, these data may be relevant to gene therapy studies.
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    Immuno-histochemical expression of a1, a2 and a3 integrin subunits during angiogenesis in vitro
    (Murcia: F. Hernández, 2004) Suda, H.; Asami, Y.; Murata, E.; Fujita, K.; Akita, M.
    Aortic explants were obtained from mouse fetuses and cultured in collagen gels. Immuno-fluorescence microscopy, antibodies (anti a1, a2 and a3 integrin subunits) were used. Fibroblastic cells migrated from the aortic explant after one day of cultivation. The migrating cells located in the peripheral part of the aortic explant were positive for a1 and a2 integrin subunit antibodies. Immuno-fluorescence-positive staining for the a3 integrin subunit antibody was clearly seen in the migrating cells located near the aortic explant and surrounding tube-like structures. In an immuno-electron microscope study performed by pre-embedding immuno labeling, gold particles associated with the a3 integrin subunit were found to reside on the membranes of the cells surrounding the capillary-like tubes. Two synthetic peptides, GRGDSP (Gly-Arg-Gly-Asp-Ser-Pro) and KDGEA (Lys-Asp-Gly-Glu-Ala), were added to the growth medium to study their effects on cell migration. KDGEA, a compound containing the recognition sequence for a2ß1 integrin, decreased cell migration, while GRGDSP exhibited no effect. The migration of fibroblastic cells is an important phenomenon for tube formation. The present study suggested that the a1 and a2 integrin subunits are both involved in the cell migration, and more specifically, that the a2 integrin subunit participates in cell migration through the KDGEA sequence. The a3 integrin subunit played a role in tube formation.
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    Ion channels and actin: A tale of two friends
    (Universidad de Murcia, Departamento de Histología e Histopatología, 2025) Sesti Federico; Forzisi Elena; Biología Celular e Histología
    An increasing number of studies highlight ion channels as multifunctional proteins involved in diverse cellular processes, including proliferation, differentiation, adhesion, migration, morphology, and programmed cell death (apoptosis). Given these broad roles, it is not surprising that ion channels interact closely with actin, a ubiquitous cytoskeletal component that participates in a vast array of biological functions. Ion channels depend on the actin cytoskeleton for essential activities such as trafficking to and from the plasma membrane. Conversely, actin dynamics are often modulated by ion channels during various cellular events. In this review, we provide an overview of the field and discuss key examples that reveal emerging patterns in the bidirectional interactions between ion channels and the actin cytoskeleton
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    The role of integrins in primary and secondary brain tumors
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2016) Schittenhelm, Jens; Tabatabai, Ghazaleh; Sipos, Bence
    The tumor environment plays an integral part in the biology of cancer, participating in tumor initiation, progression, and response to therapy. Integrins, a family of cell surface receptors, bridge the extracellular matrix to the intracellular cytoskeleton. Since their first characterization 25 years ago, a vast amount of work has been performed to understand the essential role of integrins in cell development, tissue organization, tumor growth, vessel development and their signaling mechanisms. Their potential as therapeutic targets in various types of cancer is intensively studied. In this review, we discuss the expression patterns and functional role of integrin in primary brain tumors and brain metastases, provide an overview of clinical data on integrin inhibition and their potential application in imaging and therapy of these tumors.
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    The signaling network of tumor invasion
    (Murcia : F. Hernández, 2005) Wang, G.K.; Zhang, W.
    The ability of a cell to invade its surroundings is an important hallmark of malignant tumors and results from aberrant cell signaling mechanisms. The signal transduction that leads to tumor invasion can be broken down into major pathways. Even though the pathway systems are distinct in themselves, none of these pathways operate independently when it comes to transmitting signals that culminate in an invasive phenotype. That is, the malignant change in one receptor not only leads to malignant changes directly downstream but can also affect the molecules of many other pathways. Three major pathway systems involved in tumor invasion are discussed in this review: the integrin system, the insulin-like growth factor system, and the Rho family GTPases. Here we see that although the individual signaling systems can each contribute to invasion, each system is networked to others and should not be considered isolated. Each system is first reviewed as independent contributors to an invasive phenotype and then discussed in the context of interacting pathways that collectively result in tumor invasion.