Mitochondrial Phosphopantetheinylation is Required for Oxidative Function.

4'-phosphopantetheinyl (4'PP) groups are essential co-factors added to target proteins by p hospho p antetheinyl transferase (PPTase) enzymes. Although mitochondrial 4'PP-modified proteins have been described for decades, a mitochondrially-localized PPTase has never been found in mammals. We discovered that the cytoplasmic PPTase a mino a dipate s emialdehyde d ehydrogenase p hospho p antetheinyl t ransferase (AASDHPPT) is required for mitochondrial respiration and oxidative metabolism.

Differential roles of FOXC2 in the trabecular meshwork and Schlemm's canal in glaucomatous pathology.

Impaired development and maintenance of Schlemm's canal (SC) are associated with perturbed aqueous humor outflow and intraocular pressure. The angiopoietin (ANGPT)/TIE2 signaling pathway regulates SC development and maintenance, whereas the molecular mechanisms of crosstalk between SC and the neural crest (NC)-derived neighboring tissue, the trabecular meshwork (TM), are poorly understood. Here, we show NC-specific forkhead box ( deletion in mice results in impaired SC morphogenesis, loss of SC identity, and elevated intraocular pressure.

Endothelial FOXC1 and FOXC2 promote intestinal regeneration after ischemia-reperfusion injury.

Intestinal ischemia underlies several clinical conditions and can result in the loss of the intestinal mucosal barrier. Ischemia-induced damage to the intestinal epithelium is repaired by stimulation of intestinal stem cells (ISCs), and paracrine signaling from the vascular niche regulates intestinal regeneration. Here, we identify FOXC1 and FOXC2 as essential regulators of paracrine signaling in intestinal regeneration after ischemia-reperfusion (I/R) injury.

Molecular Mechanisms Controlling Lymphatic Endothelial Junction Integrity.

The lymphatic system is essential for lipid absorption/transport from the digestive system, maintenance of tissue fluid and protein homeostasis, and immune surveillance. Despite recent progress toward understanding the cellular and molecular mechanisms underlying the formation of the lymphatic vascular system, the nature of lymphatic vessel abnormalities and disease in humans is complex and poorly understood. The mature lymphatic vasculature forms a hierarchical network in which lymphatic endothelial cells (LECs) are joined by functionally specialized cell-cell junctions to maintain the integrity of lymphatic vessels.

Control of endothelial tubulogenesis by Rab and Ral GTPases, and apical targeting of caveolin-1-labeled vacuoles.

Here, we examine known GTPase regulators of vesicle trafficking events to assess whether they affect endothelial cell (EC) lumen and tube formation. We identify novel roles for the small GTPases Rab3A, Rab3B, Rab8A, Rab11A, Rab27A, RalA, RalB and caveolin-1 in co-regulating membrane trafficking events that control EC lumen and tube formation. siRNA suppression of individual GTPases such as Rab3A, Rab8A, and RalB markedly inhibit tubulogenesis, while greater blockade is observed with combinations of siRNAs such as Rab3A and Rab3B, Rab8A and Rab11A, and RalA and RalB.

Shear stimulation of FOXC1 and FOXC2 differentially regulates cytoskeletal activity during lymphatic valve maturation.

Mutations in the transcription factor are predominately associated with lymphedema. Herein, we demonstrate a key role for related factor FOXC1, in addition to FOXC2, in regulating cytoskeletal activity in lymphatic valves. FOXC1 is induced by laminar, but not oscillatory, shear and inducible, endothelial-specific deletion impaired postnatal lymphatic valve maturation in mice.

The Role of Lymphatic Vascular Function in Metabolic Disorders.

In addition to its roles in the maintenance of interstitial fluid homeostasis and immunosurveillance, the lymphatic system has a critical role in regulating transport of dietary lipids to the blood circulation. Recent work within the past two decades has identified an important relationship between lymphatic dysfunction and patients with metabolic disorders, such as obesity and type 2 diabetes, in part characterized by abnormal lipid metabolism and transport. Utilization of several genetic mouse models, as well as non-genetic models of diet-induced obesity and metabolic syndrome, has demonstrated that abnormal lymphangiogenesis and poor collecting vessel function, characterized by impaired contractile ability and perturbed barrier integrity, underlie lymphatic dysfunction relating to obesity, diabetes, and metabolic syndrome.

Src- and Fyn-dependent apical membrane trafficking events control endothelial lumen formation during vascular tube morphogenesis.

Here we examine the question of how endothelial cells (ECs) develop their apical membrane surface domain during lumen and tube formation. We demonstrate marked apical membrane targeting of activated Src kinases to this apical domain during early and late stages of this process. Immunostaining for phosphotyrosine or phospho-Src reveals apical membrane staining in intracellular vacuoles initially.

Rasip1-Mediated Rho GTPase Signaling Regulates Blood Vessel Tubulogenesis via Nonmuscle Myosin II.

Rationale: Vascular tubulogenesis is essential to cardiovascular development. Within initial vascular cords of endothelial cells, apical membranes are established and become cleared of cell-cell junctions, thereby allowing continuous central lumens to open. Rasip1 (Ras-interacting protein 1) is required for apical junction clearance, as well as for regulation of Rho GTPase (enzyme that hydrolyzes GTP) activity.

Molecular Signaling Pathways Controlling Vascular Tube Morphogenesis and Pericyte-Induced Tube Maturation in 3D Extracellular Matrices.

During capillary network formation, ECs establish interconnecting tubes with defined lumens that reside within vascular guidance tunnels (physical spaces generated during EC tubulogenesis). Pericytes are recruited to EC tubes within these tunnels and capillary basement membrane deposition occurs to facilitate tube maturation. Here, we discuss molecular mechanisms controlling EC tubulogenesis demonstrating the involvement of integrins, MT1-MMP, extracellular matrix, Cdc42, Rac1, Rac2, k-Ras, Rap1b, and key downstream effectors including Pak2, Pak4, IQGAP1, MRCKβ, and Rasip1.

Foxc1 and Foxc2 deletion causes abnormal lymphangiogenesis and correlates with ERK hyperactivation.

The lymphatic vasculature is essential for maintaining interstitial fluid homeostasis, and dysfunctional lymphangiogenesis contributes to various pathological processes, including inflammatory disease and tumor metastasis. Mutations in FOXC2 are dominantly associated with late-onset lymphedema; however, the precise role of FOXC2 and a closely related factor, FOXC1, in the lymphatic system remains largely unknown. Here we identified a molecular cascade by which FOXC1 and FOXC2 regulate ERK signaling in lymphatic vessel growth.

Cdc42 and k-Ras Control Endothelial Tubulogenesis through Apical Membrane and Cytoskeletal Polarization: Novel Stimulatory Roles for GTPase Effectors, the Small GTPases, Rac2 and Rap1b, and Inhibitory Influence of Arhgap31 and Rasa1.

A critical and understudied property of endothelial cells is their ability to form lumens and tube networks. Although considerable information has been obtained concerning these issues, including the role of Cdc42 and Rac1 and their effectors such as Pak2, Pak4, Par6b, and co-regulators such as integrins, MT1-MMP and Par3; many key questions remain that are necessary to elucidate molecular and signaling requirements for this fundamental process. In this work, we identify new small GTPase regulators of EC tubulogenesis including k-Ras, Rac2 and Rap1b that act in conjunction with Cdc42 as well as the key downstream effectors, IQGAP1, MRCKβ, beta-Pix, GIT1, and Rasip1 (which can assemble into multiprotein complexes with key regulators including α2β1 integrin and MT1-MMP).

Molecular control of capillary morphogenesis and maturation by recognition and remodeling of the extracellular matrix: functional roles of endothelial cells and pericytes in health and disease.

This review addresses fundamental mechanisms underlying how capillaries form in three-dimensional extracellular matrices and how endothelial cells (ECs) and pericytes co-assemble to form capillary networks. In addition to playing a critical role in supplying oxygen and nutrients to tissues, recent work suggests that blood vessels supply important signals to facilitate tissue development. Here, we hypothesize that another major function of capillaries is to supply signals to suppress major disease mechanisms including inflammation, infection, thrombosis, hemorrhage, edema, ischemic injury, fibrosis, autoimmune disease and tumor growth/progression.

Cdc42 is required for cytoskeletal support of endothelial cell adhesion during blood vessel formation in mice.

The Rho family of small GTPases has been shown to be required in endothelial cells (ECs) during blood vessel formation. However, the underlying cellular events controlled by different GTPases remain unclear. Here, we assess the cellular mechanisms by which Cdc42 regulates mammalian vascular morphogenesis and maintenance.

Control of vascular tube morphogenesis and maturation in 3D extracellular matrices by endothelial cells and pericytes.

An important advance using in vitro EC tube morphogenesis and maturation models has been the development of systems using serum-free defined media. Using this approach, the growth factors and cytokines which are actually necessary for these events can be determined. The first model developed by our laboratory was such a system where we showed that phorbol ester was needed in order to promote survival and tube morphogenesis in 3D collagen matrices.

Biochemical mechanism of HIV-1 resistance to rilpivirine.

Rilpivirine (RPV) is a second generation nonnucleoside reverse transcriptase (RT) inhibitor (NNRTI) that efficiently inhibits HIV-1 resistant to first generation NNRTIs. Virological failure during therapy with RPV and emtricitabine is associated with the appearance of E138K and M184I mutations in RT. Here we investigate the biochemical mechanism of RT inhibition and resistance to RPV.

Cutaneous disseminated xanthogranuloma in an adult: case report and review of the literature.

Xanthogranuloma (XG) is a rare, non-Langerhans cell histiocytosis (LCH) that most commonly presents in infancy or early childhood. The condition is typified by the formation of reddish to yellow papules and nodules that are usually solitary. Xanthogranuloma rarely occurs in adults with immunohistochemical features similar to those seen in juvenile XG.

Keeping them connected--reducing drug-related harm in Australian schools from a Catholic perspective.

In this Harm Reduction Digest, Father Peter Norden of Jesuit Social Services (Australia) summarises the findings of a report of a consultation into how Catholic schools in Australia address substance use by school students. The report showed that while in the past the 'zero tolerance' approach had been the norm, more recently there had been a growing awareness in Catholic schools that it is possible to respond to the needs of drug-using students while being respectful of the duty of care to other students. Moreover, harm reduction was accepted as a serious objective for drug policy and practice in Australian Catholic schools.

Health-related quality of life of pediatric patients receiving allogeneic stem cell or bone marrow transplantation: results of a longitudinal, multi-center study.

The results of a 5-year longitudinal prospective study about the health-related quality of life (HRQL) of pediatric patients receiving allogeneic bone marrow or stem cell transplantation (BMT) are described. The patients' HRQL was assessed twice before, and five times after BMT, the end point being 1 year after BMT. For the measurement of HRQL, standardized questionnaires were completed by patients, parents and physicians.