Polydom/SVEP1 binds to Tie1 and promotes migration of lymphatic endothelial cells.

Polydom is an extracellular matrix protein involved in lymphatic vessel development. Polydom-deficient mice die immediately after birth due to defects in lymphatic vessel remodeling, but the mechanism involved is poorly understood. Here, we report that Polydom directly binds to Tie1, an orphan receptor in the Angiopoietin-Tie axis, and facilitates migration of lymphatic endothelial cells (LECs) in a Tie1-dependent manner.

Combined administration of laminin-221 and prostacyclin agonist enhances endogenous cardiac repair in an acute infarct rat heart.

Although endogenous cardiac repair by recruitment of stem cells may serve as a therapeutic approach to healing a damaged heart, how to effectively enhance the migration of stem cells to the damaged heart is unclear. Here, we examined whether the combined administration of prostacyclin agonist (ONO1301), a multiple-cytokine inducer, and stem cell niche laminin-221 (LM221), enhances regeneration through endogenous cardiac repair. We administered ONO1301- and LM221-immersed sheets, LM221-immersed sheets, ONO1301-immersed sheets, and PBS-immersed sheets (control) to an acute infarction rat model.

Laminin-221 Enhances Therapeutic Effects of Human-Induced Pluripotent Stem Cell-Derived 3-Dimensional Engineered Cardiac Tissue Transplantation in a Rat Ischemic Cardiomyopathy Model.

Background Extracellular matrix, especially laminin-221, may play crucial roles in viability and survival of human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) after in vivo transplant. Then, we hypothesized laminin-221 may have an adjuvant effect on therapeutic efficacy by enhancing cell viability and survival after transplantation of 3-dimensional engineered cardiac tissue (ECT) to a rat model of myocardial infarction. Methods and Results In vitro study indicates the impacts of laminin-221 on hiPS-CMs were analyzed on the basis of mechanical function, mitochondrial function, and tolerance to hypoxia.

Laminin is the ECM niche for trophoblast stem cells.

The niche is a specialized microenvironment for tissue stem cells in vivo. It has long been emphasized that niche ECM molecules act on tissue stem cells to regulate their behavior, but the molecular entities of these interactions remain to be fully elucidated. Here, we report that laminin forms the in vivo ECM niche for trophoblast stem cells (TSCs), the tissue stem cells of the placenta.

Expression of polydom in dermal neurofibroma and surrounding dermis in von Recklinghausen's disease.

Background: Neurofibromas in von Recklinghausen's disease (vRD) can develop in the dermis. Therefore, we hypothesized that a dermal niche exists that promotes the development of these neurofibromas in subjects with vRD.

Objective: The purpose of this study is to examine the function of polydom, known as a ligand for integrin, mediating cell adhesion, and expressed in mouse nerve tissue, in promotion of neurofibroma.

Laminin-511 Supplementation Enhances Stem Cell Localization With Suppression in the Decline of Cardiac Function in Acute Infarct Rats.

Background: The extracellular matrix, in particular basement membrane components such as laminins (LMs), is essential for stem cell differentiation and self-renewal. LM511 and LM221 are the main extracellular matrix components of the epicardium, where stem cells were abundant. Here, we examined whether LMs affected the regeneration process by modulating stem cell activities.

Recombinant laminin fragments endowed with collagen-binding activity: A tool for conferring laminin-like cell-adhesive activity to collagen matrices.

Laminins are major components of basement membranes that sustain a wide variety of stem cells. Among 15 laminin isoforms, laminin-511 and its E8 fragment (LM511E8) have been shown to strongly promote the adhesion and proliferation of human pluripotent stem cells. The aim of this study was to endow the cell-adhesive activity of laminin-511 on collagen matrices, thereby fabricating collagen-based culture scaffolds for stem cells with defined composition.

Polydom Is an Extracellular Matrix Protein Involved in Lymphatic Vessel Remodeling.

Rationale: Lymphatic vasculature constitutes a second vascular system essential for immune surveillance and tissue fluid homeostasis. Maturation of the hierarchical vascular structure, with a highly branched network of capillaries and ducts, is crucial for its function. Environmental cues mediate the remodeling process, but the mechanism that underlies this process is largely unknown.

In situ detection of integrin ligands.

Integrins are cell surface receptors for cell adhesion. Integrin-mediated cell adhesion regulates various cellular processes, including cell survival, migration, proliferation, and differentiation. In vivo, ligands for integrins are immobilized within extracellular matrices, insoluble sheet-like or fibrous supramolecular complexes that associate with or surround cells.

In Situ Detection of Integrin Ligands.

Integrins are cell surface receptors for cell adhesion. Integrin-mediated cell adhesion regulates various cellular processes, including cell survival, migration, proliferation, and differentiation. In vivo, ligands for integrins are immobilized within extracellular matrices, insoluble sheet-like or fibrous supramolecular complexes that associate with or surround cells.

Polydom/SVEP1 is a ligand for integrin α9β1.

A variety of proteins, including tenascin-C and osteopontin, have been identified as ligands for integrin α9β1. However, their affinities for integrin α9β1 are apparently much lower than those of other integrins (e.g.

Molecular basis of the recognition of nephronectin by integrin alpha8beta1.

Integrin alpha8beta1 interacts with a variety of Arg-Gly-Asp (RGD)-containing ligands in the extracellular matrix. Here, we examined the binding activities of alpha8beta1 integrin toward a panel of RGD-containing ligands. Integrin alpha8beta1 bound specifically to nephronectin with an apparent dissociation constant of 0.

The C-terminal region of laminin beta chains modulates the integrin binding affinities of laminins.

Laminins are major cell-adhesive proteins in basement membranes that are capable of binding to integrins. Laminins consist of three chains (alpha, beta, and gamma), in which three laminin globular modules in the alpha chain and the Glu residue in the C-terminal tail of the gamma chain have been shown to be prerequisites for binding to integrins. However, it remains unknown whether any part of the beta chain is involved in laminin-integrin interactions.

Laminin isoforms containing the gamma3 chain are unable to bind to integrins due to the absence of the glutamic acid residue conserved in the C-terminal regions of the gamma1 and gamma2 chains.

Laminins are the major cell adhesive proteins in basement membranes, and consist of three subunits termed alpha, beta, and gamma. Recently, we found that the Glu residue at the third position from the C termini of the gamma1 and gamma2 chains is critically involved in integrin binding by laminins. However, the gamma3 chain lacks this Glu residue, suggesting that laminin isoforms containing the gamma3 chain may be unable to bind to integrins.

Probing the interaction of tetraspanin CD151 with integrin alpha 3 beta 1 using a panel of monoclonal antibodies with distinct reactivities toward the CD151-integrin alpha 3 beta 1 complex.

CD151, a member of the tetraspanin family of proteins, forms a stable complex with integrin alpha 3 beta 1 and regulates integrin-mediated cell-substrate adhesion. However, the molecular basis of the stable association of CD151 with integrin alpha 3 beta 1 remains poorly understood. In the present study, we show that a panel of anti-human CD151 mAbs (monoclonal antibodies) could be divided into three groups on the basis of their abilities to co-immunoprecipitate integrin alpha 3: Group-1 mAbs were devoid of sufficient activities to co-precipitate integrin alpha 3 under both low- and high-stringency detergent conditions; Group-2 mAbs co-precipitated integrin alpha 3 under low-stringency conditions; and Group-3 mAbs exhibited strong co-precipitating activities under both conditions.