Showing papers by "Kari Alitalo published in 2013"
TL;DR: The results suggest that the skin contains a hypertonic interstitial fluid compartment in which MPS cells exert homeostatic and blood pressure-regulatory control by local organization of interstitial electrolyte clearance via TONEBP and VEGFC/VEGFR3-mediated modification of cutaneous lymphatic capillary function.
Abstract: The skin interstitium sequesters excess Na+ and Cl- in salt-sensitive hypertension. Mononuclear phagocyte system (MPS) cells are recruited to the skin, sense the hypertonic electrolyte accumulation in skin, and activate the tonicity-responsive enhancer-binding protein (TONEBP, also known as NFAT5) to initiate expression and secretion of VEGFC, which enhances electrolyte clearance via cutaneous lymph vessels and increases eNOS expression in blood vessels. It is unclear whether this local MPS response to osmotic stress is important to systemic blood pressure control. Herein, we show that deletion of TonEBP in mouse MPS cells prevents the VEGFC response to a high-salt diet (HSD) and increases blood pressure. Additionally, an antibody that blocks the lymph-endothelial VEGFC receptor, VEGFR3, selectively inhibited MPS-driven increases in cutaneous lymphatic capillary density, led to skin Cl- accumulation, and induced salt-sensitive hypertension. Mice overexpressing soluble VEGFR3 in epidermal keratinocytes exhibited hypoplastic cutaneous lymph capillaries and increased Na+, Cl-, and water retention in skin and salt-sensitive hypertension. Further, we found that HSD elevated skin osmolality above plasma levels. These results suggest that the skin contains a hypertonic interstitial fluid compartment in which MPS cells exert homeostatic and blood pressure-regulatory control by local organization of interstitial electrolyte clearance via TONEBP and VEGFC/VEGFR3-mediated modification of cutaneous lymphatic capillary function.
345 citations
TL;DR: A significantly more detailed view and novel model of early lymphatic development is presented and vascular endothelial growth factor C (VEGF‐C) and the matrix component CCBE1 indispensable for LEC budding and migration are found.
Abstract: During mammalian development, a subpopulation of endothelial cells in the cardinal vein (CV) expresses lymphatic-specific genes and subsequently develops into the first lymphatic structures, collectively termed as lymph sacs. Budding, sprouting and ballooning of lymphatic endothelial cells (LECs) have been proposed to underlie the emergence of LECs from the CV, but the exact mechanisms of lymph vessel formation remain poorly understood. Applying selective plane illumination-based ultramicroscopy to entire wholemount-immunostained mouse embryos, we visualized the complete developing vascular system with cellular resolution. Here, we report emergence of the earliest detectable LECs as strings of loosely connected cells between the CV and superficial venous plexus. Subsequent aggregation of LECs resulted in formation of two distinct, previously unidentified lymphatic structures, the dorsal peripheral longitudinal lymphatic vessel (PLLV) and the ventral primordial thoracic duct (pTD), which at later stages formed a direct contact with the CV. Providing new insights into their function, we found vascular endothelial growth factor C (VEGF-C) and the matrix component CCBE1 indispensable for LEC budding and migration. Altogether, we present a significantly more detailed view and novel model of early lymphatic development.
257 citations
TL;DR: Treatment of organoids and mice with anti-inflammatory agents suppresses the SIR and prevents p53-deficient organoid transformation and mouse carcinogenesis, suggesting that SIR/para-inflammation suppression may constitute a key mechanism in the anticarcinogenic effects of nonsteroidal anti- inflammatory drugs.
182 citations
TL;DR: The VEGFR and Tie families, their involvement in developmental and pathological angiogenesis, and the different possibilities for targeting them to either block or enhanceAngiogenesis and lymphangiogenesis are reviewed.
Abstract: The endothelial cell is the essential cell type forming the inner layer of the vasculature. Two families of receptor tyrosine kinases (RTKs) are almost completely endothelial cell specific: the vascular endothelial growth factor (VEGF) receptors (VEGFR1-3) and the Tie receptors (Tie1 and Tie2). Both are key players governing the generation of blood and lymphatic vessels during embryonic development. Because the growth of new blood and lymphatic vessels (or the lack thereof) is a central element in many diseases, the VEGF and the Tie receptors provide attractive therapeutic targets in various diseases. Indeed, several drugs directed to these RTK signaling pathways are already on the market, whereas many are in clinical trials. Here we review the VEGFR and Tie families, their involvement in developmental and pathological angiogenesis, and the different possibilities for targeting them to either block or enhance angiogenesis and lymphangiogenesis.
141 citations
TL;DR: Overall, it is shown that two key vascular growth factor receptors — VEGFR2 and Tie2 — strikingly but differentially regulate decidual angiogenesis and vascular remodelling in rapidly growing and regressing uteri in an organotypic manner.
Abstract: The features and regulation of uterine angiogenesis and vascular remodelling during pregnancy are poorly defined. Here we show that dynamic and variable decidual angiogenesis (sprouting, intussusception and networking), and active vigorous vascular remodelling such as enlargement and elongation of 'vascular sinus folding' (VSF) and mural cell drop-out occur distinctly in a spatiotemporal manner in the rapidly growing mouse uterus during early pregnancy - just after implantation but before placentation. Decidual angiogenesis is mainly regulated through VEGF-A secreted from the progesterone receptor (PR)-expressing decidual stromal cells which are largely distributed in the anti-mesometrial region (AMR). In comparison, P4 -PR-regulated VEGF-A-VEGFR2 signalling, ligand-independent VEGFR3 signalling and uterine natural killer (uNK) cells positively and coordinately regulate enlargement and elongation of VSF. During the postpartum period, Tie2 signalling could be involved in vascular maturation at the endometrium in a ligand-independent manner, with marked reduction of VEGF-A, VEGFR2 and PR expressions. Overall, we show that two key vascular growth factor receptors - VEGFR2 and Tie2 - strikingly but differentially regulate decidual angiogenesis and vascular remodelling in rapidly growing and regressing uteri in an organotypic manner.
128 citations
TL;DR: To improve anti‐angiogenic therapies in cancer patients, it is necessary to identify additional molecular targets important for tumor angiogenesis, and to get mechanistic insight into their interactions for eventual combinatorial targeting.
121 citations
TL;DR: A mutation in zebrafish vegfc is identified that severely affects lymphatic development and leads to angiogenesis defects on sensitized genetic backgrounds and an autocrine Vegfc/Flt4 loop plays an important role in migratory persistence and filopodia stability during sprouting.
Abstract: Vascular endothelial growth factor C (Vegfc) is a secreted protein that guides lymphatic development in vertebrate embryos. However, its role during developmental angiogenesis is not well characterized. Here, we identify a mutation in zebrafish vegfc that severely affects lymphatic development and leads to angiogenesis defects on sensitized genetic backgrounds. The um18 mutation prematurely truncated Vegfc, blocking its secretion and paracrine activity but not its ability to activate its receptor Flt4. When expressed in endothelial cells, vegfcum18 could not rescue lymphatic defects in mutant embryos, but induced ectopic blood vessel branching. Furthermore, vegfc-deficient endothelial cells did not efficiently contribute to tip cell positions in developing sprouts. Computational modeling together with assessment of endothelial cell dynamics by time-lapse analysis suggested that an autocrine Vegfc/Flt4 loop plays an important role in migratory persistence and filopodia stability during sprouting. Our results suggest that Vegfc acts in two distinct modes during development: as a paracrine factor secreted from arteries to guide closely associated lymphatic vasculature and as an autocrine factor to drive migratory persistence during angiogenesis.
106 citations
TL;DR: In this paper, the crystal structures of VEGF-C in complex with VEGFR-3 domains D1-2 and of the VEGfr-3 D4-5 homodimer were analyzed.
Abstract: Vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) are key drivers of blood and lymph vessel formation in development, but also in several pathological processes. VEGF-C signaling through VEGFR-3 promotes lymphangiogenesis, which is a clinically relevant target for treating lymphatic insufficiency and for blocking tumor angiogenesis and metastasis. The extracellular domain of VEGFRs consists of seven Ig homology domains; domains 1–3 (D1-3) are responsible for ligand binding, and the membrane-proximal domains 4–7 (D4-7) are involved in structural rearrangements essential for receptor dimerization and activation. Here we analyzed the crystal structures of VEGF-C in complex with VEGFR-3 domains D1-2 and of the VEGFR-3 D4-5 homodimer. The structures revealed a conserved ligand-binding interface in D2 and a unique mechanism for VEGFR dimerization and activation, with homotypic interactions in D5. Mutation of the conserved residues mediating the D5 interaction (Thr446 and Lys516) and the D7 interaction (Arg737) compromised VEGF-C induced VEGFR-3 activation. A thermodynamic analysis of VEGFR-3 deletion mutants showed that D3, D4-5, and D6-7 all contribute to ligand binding. A structural model of the VEGF-C/VEGFR-3 D1-7 complex derived from small-angle X-ray scattering data is consistent with the homotypic interactions in D5 and D7. Taken together, our data show that ligand-dependent homotypic interactions in D5 and D7 are essential for VEGFR activation, opening promising possibilities for the design of VEGFR-specific drugs.
87 citations
TL;DR: Lymphangiogenic growth factors improve lymphatic vessel regeneration and lymph node function after lymph node transfer and provide a basis for future clinical trials in lymphedema patients.
Abstract: Objective:Our objective was to define the optimal growth factor treatment to be used in combination with lymph node transfer to normalize lymphatic vascular anatomy.Background:In the lymph node transfer method, lymphatic anastomoses are expected to form spontaneously. However, lymphangiogenic growth
80 citations
TL;DR: This review will focus on Notch signaling in the vertebrate vascular and nervous systems and examine its role in angiogenesis, neurogenesis, and neurovascular interactions, and highlight the molecular relationships of the Notch pathway with vascular endothelial growth factors and their high-affinity tyrosine kinase VEGF receptors.
Abstract: Notch cell interaction mechanism governs cell fate decisions in many different cell contexts throughout the lifetime of all Metazoan species. It links the fate of one cell to that of its neighbors through cell-to-cell contacts, and binding of Notch receptors expressed on one cell to their membrane bound ligands on an adjacent cell. Environmental cues, such as growth factors and extracellular matrix molecules, superimpose a dynamic regulation on this canonical Notch signaling pathway. In this review, we will focus on Notch signaling in the vertebrate vascular and nervous systems and examine its role in angiogenesis, neurogenesis, and neurovascular interactions. We will also highlight the molecular relationships of the Notch pathway with vascular endothelial growth factors (VEGFs) and their high-affinity tyrosine kinase VEGF receptors, key regulators of both angiogenesis and neurogenesis.
75 citations
TL;DR: It is shown that VEGF-B, unlike other VEGFs, did not require D3 interactions for high-affinity binding, and this may aid in designing VEGFR-1–targeting compounds that can inhibit or stimulate angiogenesis.
Abstract: `Vascular endothelial growth factors (VEGFs) regulate blood and lymphatic vessel development through VEGF receptors (VEGFRs). The VEGFR immunoglobulin homology domain 2 (D2) is critical for ligand binding, and D3 provides additional interaction sites. VEGF-B and placenta growth factor (PlGF) bind to VEGFR-1 with high affinity, but only PlGF is angiogenic in most tissues. We show that VEGF-B, unlike other VEGFs, did not require D3 interactions for high-affinity binding. VEGF-B with a PlGF-derived L1 loop (B-L1 P ) stimulated VEGFR-1 activity, whereas PlGF with a VEGF-B–derived L1 loop (P-L1 B ) did not. Unlike P-L1 B and VEGF-B, B-L1 P and PlGF were also angiogenic in mouse skeletal muscle. Furthermore, B-L1 P also bound to VEGFR-2 and activated downstream signaling. These results establish a role for L1-mediated D3 interactions in VEGFR activation in endothelial cells and indicate that VEGF-B is a high-affinity VEGFR-1 ligand that, unlike PlGF, cannot efficiently induce signaling downstream of VEGFR-1.
TL;DR: The VEGF–angiopoietin-1 chimera is a potent angiogenic factor that triggers a novel mode of V EGF receptor-2 activation, promoting less vessel leakiness, less tissue inflammation, and better perfusion in ischemic muscle than VEGf.
Abstract: Background—There is an unmet need for proangiogenic therapeutic molecules for the treatment of tissue ischemia in cardiovascular diseases. However, major inducers of angiogenesis such as vascular endothelial growth factor (VEGF/VEGF-A) have side effects that limit their therapeutic utility in vivo, especially at high concentrations. Angiopoietin-1 has been considered to be a blood vessel stabilization factor that can inhibit the intrinsic property of VEGF to promote vessel leakiness. In this study, we have designed and tested the angiogenic properties of chimeric molecules consisting of receptor-binding parts of VEGF and angiopoietin-1. We aimed at combining the activities of both factors into 1 molecule for easy delivery and expression in target tissues. Methods and Results—The VEGF–angiopoietin-1 (VA1) chimeric protein bound to both VEGF receptor-2 and Tie2 and induced the activation of both receptors. Detailed analysis of VA1 versus VEGF revealed differences in the kinetics of VEGF receptor-2 activatio...
TL;DR: Activation of the hypoxia response by Hif-P4H-2 inhibition in endothelial cells appears to be a major determinant of ischemic cardioprotection and justifies the exploration of systemic small-molecule HIF-P 4H- 2 inhibitors for isChemic heart disease.
Abstract: Small-molecule inhibition of hypoxia-inducible factor prolyl 4-hydroxylases (HIF-P4Hs) is being explored for the treatment of anemia. Previous studies have suggested that HIF-P4H-2 inhibition may also protect the heart from an ischemic insult. Hif-p4h-2(gt/gt) mice, which have 76 to 93% knockdown of Hif-p4h-2 mRNA in endothelial cells, fibroblasts, and cardiomyocytes and normoxic stabilization of Hif-α, were subjected to ligation of the left anterior descending coronary artery (LAD). Hif-p4h-2 deficiency resulted in increased survival, better-preserved left ventricle (LV) systolic function, and a smaller infarct size. Surprisingly, a significantly larger area of the LV remained perfused during LAD ligation in Hif-p4h-2(gt/gt) hearts than in wild-type hearts. However, no difference was observed in collateral vessels, while the size of capillaries, but not their number, was significantly greater in Hif-p4h-2(gt/gt) hearts than in wild-type hearts. Hif-p4h-2(gt/gt) mice showed increased cardiac expression of endothelial Hif target genes for Tie-2, apelin, APJ, and endothelial nitric oxide (NO) synthase (eNOS) and increased serum NO concentrations. Remarkably, blockage of Tie-2 signaling was sufficient to normalize cardiac apelin and APJ expression and resulted in reversal of the enlarged-capillary phenotype and ischemic cardioprotection in Hif-p4h-2(gt/gt) hearts. Activation of the hypoxia response by HIF-P4H-2 inhibition in endothelial cells appears to be a major determinant of ischemic cardioprotection and justifies the exploration of systemic small-molecule HIF-P4H-2 inhibitors for ischemic heart disease.
TL;DR: Gene silencing and cell depletion strategies demonstrate that TIE2 induction in macrophages is required to promote their proarteriogenic functions, enabling collateral vessel formation following arterial obstruction, suggesting possible new venues for the treatment of ischaemic disorders.
Abstract: Occlusion of the main arterial route redirects blood flow to the collateral circulation. We previously reported that macrophages genetically modified to express low levels of prolyl hydroxylase domain protein 2 (PHD2) display an arteriogenic phenotype, which promotes the formation of collateral vessels and protects the skeletal muscle from ischaemic necrosis. However, the molecular mechanisms underlying this process are unknown. Here, we demonstrate that femoral artery occlusion induces a switch in macrophage phenotype through angiopoietin-1 (ANG1)-mediated Phd2 repression. ANG blockade by a soluble trap prevented the downregulation of Phd2 expression in macrophages and their phenotypic switch, thus inhibiting collateral growth. ANG1-dependent Phd2 repression initiated a feed-forward loop mediated by the induction of the ANG receptor TIE2 in macrophages. Gene silencing and cell depletion strategies demonstrate that TIE2 induction in macrophages is required to promote their proarteriogenic functions, enabling collateral vessel formation following arterial obstruction. These results indicate an indispensable role for TIE2 in sustaining in situ programming of macrophages to a proarteriogenic, M2-like phenotype, suggesting possible new venues for the treatment of ischaemic disorders.
TL;DR: It is concluded that lymphangiogenesis triggered by IL-1β overexpression in mouse airways is driven by VEGF-C/D from macrophages, but not neutrophils, recruited by chemokines from epithelial cells that express IL1R1.
Abstract: These studies used bi-transgenic Clara cell secretory protein (CCSP)/IL-1β mice that conditionally overexpress IL-1β in Clara cells to determine whether IL-1β can promote angiogenesis and lymphangiogenesis in airways. Doxycycline treatment induced rapid, abundant, and reversible IL-1β production, influx of neutrophils and macrophages, and conspicuous and persistent lymphangiogenesis, but surprisingly no angiogenesis. Gene profiling showed many up-regulated genes, including chemokines ( Cxcl1, Ccl7 ), cytokines (tumor necrosis factor α, IL-1β , and lymphotoxin-β), and leukocyte genes ( S100A9, Aif1/ Iba1). Newly formed lymphatics persisted after IL-1β overexpression was stopped. Further studies examined how IL1R1 receptor activation by IL-1β induced lymphangiogenesis. Inactivation of vascular endothelial growth factor (VEGF)-C and VEGF-D by adeno-associated viral vector-mediated soluble VEGFR-3 (VEGF-C/D Trap) completely blocked lymphangiogenesis, showing its dependence on VEGFR-3 ligands. Consistent with this mechanism, VEGF-C immunoreactivity was present in some Aif1/Iba1-immunoreactive macrophages. Because neutrophils contribute to IL-1β–induced lung remodeling in newborn mice, we examined their potential role in lymphangiogenesis. Triple-transgenic CCSP/IL-1β/CXCR2 −/− mice had the usual IL-1β-mediated lymphangiogenesis but no neutrophil recruitment, suggesting that neutrophils are not essential. IL1R1 immunoreactivity was found on some epithelial basal cells and neuroendocrine cells, suggesting that these cells are targets of IL-1β, but was not detected on lymphatics, blood vessels, or leukocytes. We conclude that lymphangiogenesis triggered by IL-1β overexpression in mouse airways is driven by VEGF-C/D from macrophages, but not neutrophils, recruited by chemokines from epithelial cells that express IL1R1.
TL;DR: Of the growth factors tested, PlGF emerged as the most efficient and safe angiogenic factor, hence making it a candidate for therapeutic CNS revascularization.
TL;DR: It is reported that a subpopulation of secondary motoneurons extends axons ventrally outside of the neural tubes and rostrocaudally as a fascicle beneath the dorsal aorta (DA) in zebrafish and it is found that Vegfc in the DA and Vegfr3 in the mot oneurons were essential for the axon growth.
Abstract: Blood vessels and neurons grow often side by side. However, the molecular and cellular mechanisms underlying their parallel development remain unclear. Here, we report that a subpopulation of secondary motoneurons extends axons ventrally outside of the neural tubes and rostrocaudally as a fascicle beneath the dorsal aorta (DA) in zebrafish. We tried to clarify the mechanism by which these motoneuron axons grow beneath the DA and found that Vegfc in the DA and Vegfr3 in the motoneurons were essential for the axon growth. Forced expression of either Vegfc in arteries or Vegfr3 in motoneurons resulted in enhanced axon growth of motoneurons over the DA. Both vegfr3 morphants and vegfc morphants lost the alignment of motoneuron axons with DA. In addition, forced expression of two mutant forms of Vegfr3 in motoneurons, potentially trapping endogenous Vegfc, resulted in failure of growth of motoneuron axons beneath the DA. Finally, a vegfr3 mutant fish lacked the motoneuron axons beneath the DA. Collectively, Vegfc from the preformed DA guides the axon growth of secondary motoneurons.
TL;DR: The data suggest that a high interstitial protein concentration and longstanding edema is not sufficient to induce fibrosis and inflammation characteristic for the human condition and may have implications for the understanding of the pathophysiology of this condition.
Abstract: Objective— The pathophysiology of lymphedema is incompletely understood. We asked how transcapillary fluid balance parameters and lymph flow are affected in a transgenic mouse model of primary lymphedema, which due to an inhibition of vascular endothelial growth factor receptor-3 (VEGFR-3) signaling lacks dermal lymphatics, and whether protein accumulation in the interstitium occurring in lymphedema results in inflammation.
Methods and Results— As estimated using a new optical-imaging technique, we found that this signaling defect resulted in lymph drainage in hind limb skin of K14-VEGFR-3-Ig mice that was 34% of the corresponding value in wild-type. The interstitial fluid pressure and tissue fluid volumes were significantly increased in the areas of visible swelling only, whereas the colloid osmotic pressure in plasma, and thus the colloid osmotic pressure gradient, was reduced compared to wild-type mice. An acute volume load resulted in an exaggerated interstitial fluid pressure response in transgenic mice. There was no accumulation of collagen or lipid in skin, suggesting that chronic edema presented in the K14-VEGFR-3-Ig mouse was not sufficient to induce changes in tissue composition. Proinflammatory cytokines (interleukin-2, interleukin-6, interleukin-12) in subcutaneous interstitial fluid and macrophage infiltration in skin of the paw were lower, whereas the monocyte/macrophage cell fraction in blood and spleen was higher in transgenic compared with wild-type mice.
Conclusion— Our data suggest that a high interstitial protein concentration and longstanding edema is not sufficient to induce fibrosis and inflammation characteristic for the human condition and may have implications for our understanding of the pathophysiology of this condition.
TL;DR: The findings suggest that NRP2 functions as a factor maintaining the pathological vascular network in these anomalies and could become a potential therapeutic target for the diagnosis and treatment of vascular anomalies.
Abstract: Despite multiple previous studies in the field of vascular anomalies, the mechanism(s) leading to their development, progression and maintenance has remained unclear. In this study, we have characterized the expression levels of vascular endothelial growth factors and their receptors in 33 human vascular anomalies. Analysis with quantitative real-time PCR and gene-specific assays showed higher expression of neuropilin-2 (NRP2) and VEGF-receptor-3 (VEGFR-3) mRNAs in vascular malformations (VascM) as compared to infantile hemangiomas (Hem). In addition, the expression levels of PlGF and VEGF-C mRNA were significantly higher in venous VascM when compared to the other VascM and Hem. Higher expression of NRP2 and VEGFR-3 were confirmed by immunohistochemistry. To further study the importance of NRP2 and VEGFR-3, endothelial cell (EC) cultures were established from vascular anomalies. It was found that NRP2 and VEGFR-3 mRNA levels were significantly higher in some of the VascM ECs as compared to human umbilical vein ECs which were used as control cells in the study. Furthermore, adenoviral delivery of soluble decoy NRP2 prevented the proliferation of ECs isolated from most of the vascular anomalies. Our findings suggest that NRP2 functions as a factor maintaining the pathological vascular network in these anomalies. Thus, NRP2 could become a potential therapeutic target for the diagnosis and treatment of vascular anomalies.
TL;DR: According to these results, AdsVEGFR-2 and AdsVEgFR-3 gene therapy combined with chemotherapy is safe and can be brought to clinical testing in ovarian cancer patients.
Abstract: Antiangiogenic and antilymphangiogenic gene therapy with soluble vascular endothelial growth factor receptor-2 (VEGFR-2) and soluble VEGFR-3 in combination with chemotherapy is a potential new treatment for ovarian carcinoma. We evaluated the safety, toxicology, and biodistribution of intravenous AdsVEGFR-2 and AdsVEGFR-3 combined with chemotherapy in healthy rats (n=90) before entering a clinical setting. The study groups were: AdLacZ and AdLacZ with chemotherapy as control groups, low dose AdsVEGFR-2 and AdsVEGFR-3, high dose AdsVEGFR-2 and AdsVEGFR-3, combination of low dose AdsVEGFR-2 and AdsVEGFR-3 with chemotherapy, combination of high dose AdsVEGFR-2 and AdVEGFR-3 with chemotherapy, and chemotherapy only. The follow-up time was 4 weeks. Safety and toxicology were assessed by monitoring the clinical status of the animals and by histological, hematological, and clinical chemistry parameters. For the biodistribution studies, quantitative reverse-transcriptase polymerase chain reaction (qRT-PC...
TL;DR: Results suggest AAV2 as a potential vector for gene therapy in preclinical heart transplants studies, and highlight the importance of delivery route in gene transfer studies.
Abstract: Summary Heart transplant gene therapy requires vectors with long-lasting gene expression, high cardiotropism, and minimal pathological effects. Here, we examined transduction properties of ex vivo intracoronary delivery of adeno-associated virus (AAV) serotype 2, 8, and 9 in rat syngenic and allogenic heart transplants. Adult Dark Agouti (DA) rat hearts were intracoronarily perfused ex vivo with AAV2, AAV8, or AAV9 encoding firefly luciferase and transplanted heterotopically into the abdomen of syngenic DA or allogenic Wistar–Furth (WF) recipients. Serial in vivo bioluminescent imaging of syngraft and allograft recipients was performed for 6 months and 4 weeks, respectively. Grafts were removed for PCR-, RT-PCR, and luminometer analysis. In vivo bioluminescent imaging of recipients showed that AAV9 induced a prominent and stable luciferase activity in the abdomen, when compared with AAV2 and AAV8. However, ex vivo analyses revealed that intracoronary perfusion with AAV2 resulted in the highest heart transplant transduction levels in syngrafts and allografts. Ex vivo intracoronary delivery of AAV2 resulted in efficient transgene expression in heart transplants, whereas intracoronary AAV9 escapes into adjacent tissues. In terms of cardiac transduction, these results suggest AAV2 as a potential vector for gene therapy in preclinical heart transplants studies, and highlight the importance of delivery route in gene transfer studies.
TL;DR: Early changes in T2 relaxation times and ADC values after gene therapy suggest the potential of T1 relaxation time measurements and DW-MRI as early markers of treatment response after anti-angiogenic gene therapy and chemotherapy.
Abstract: Anti-angiogenic and anti-lymphangiogenic gene therapy is a new potential method for the treatment of epithelial ovarian carcinoma. We studied the usefulness and feasibility of diffusion-weighted magnetic resonance imaging (DW-MRI) and relaxation measurements as surrogate markers of AdsVEGFR-2, AdsVEGFR-3, AdsNRP-1 and AdsNRP-2 gene therapy treatment responses in an intraperitoneal ovarian cancer mouse model (n= 45). Gene therapy was also combined with paclitaxel and carboplatin chemotherapy. Gene therapy was performed when visible tumors were noticed in MRI. Adenoviral gene transfer was dosed intravenously (2×109 pfu), while chemotherapy was dosed intraperitoneally. The study groups were: AdLacZ as controls (group I); AdsVEGFR-2 and AdsVEGFR-3 (group II); combination of AdsVEGFR-2, AdsVEGFR-3 and chemotherapy (group III) and AdsNRP-1 and AdsNRP-2 (group IV). Antitumor effectiveness was assessed by sequential MRI, immunohistochemistry, microvessel density, overall tumor growth, formation of ascites and survival time. Early responses in tumor tissue were evaluated with MRI measurements using relaxation times T2, T1ρ, TRAFF2, TRAFF4 and water apparent diffusion coefficient (ADC). The mean survival of mice (30 days) was significantly prolonged in group II as compared to controls (24 days) or other treatment groups (p= 0.003). The mean vascular density (MVD) and total vascular area (TVA) were significantly lower compared to controls in all groups: group II (p= 0.001), group III (p= 0.002), group IV (p= 0.026). T2 relaxation times were significantly increased at day 8 after the gene transfer in the combination gene therapy and chemotherapy group III compared to controls (p= 0.005). ADC values in the tumors were significantly increased in group IV at four days compared to controls (p= 0.044). Early changes in T2 relaxation times and ADC values after gene therapy suggest the potential of T2 relaxation time measurements and DW-MRI as early markers of treatment response after anti-angiogenic gene therapy and chemotherapy.
Patent•
07 Mar 2013TL;DR: In this paper, the use of anti-Ang2 antibodies or antigen-binding fragments thereof for treating ischemia is discussed, and the methods are useful for reducing microvascular permeability, increasing micro-vascular perfusion, reducing inflammation in a tissue, and treating or ameliorating diseases associated with amchemia and/or reperfusion injury.
Abstract: The disclosure is directed to methods and uses of antibodies or antigen-binding fragments thereof against Angiopoietin-2 (Ang-2). Specifically, the disclosure is direct to the use of anti-Ang2 antibodies or antigen-binding fragments thereof for treating ischemia. The methods disclosed are useful for reducing microvascular permeability, increasing microvascular perfusion, reducing inflammation in a tissue, and treating or ameliorating diseases associated with ischemia and/or reperfusion injury. The disclosed methods are also useful for protecting solid organ transplant tissue and treating or preventing chronic tissue transplant rejection.
01 Jan 2013
TL;DR: Results shed light on the mechanism of receptor activation by VEGF ligands and may help in designing chimeric proteins that could be used therapeutically to promote or inhibit angiogenesis.
Abstract: This Podcast features an interview with Kari Alitalo, author of a Research Article that appears in the 2 July 2013 issue of Science Signaling , on how two related growth factors trigger distinct biological outcomes despite binding to the same receptor. Ligands of the vascular endothelial growth factor (VEGF) family modulate the development and growth of blood and lymphatic vessels. Although the related VEGF ligands VEGF-B and placental growth factor (PlGF) both exert their biological activities by binding to VEGF receptor 1 (VEGFR-1), PlGF robustly induces angiogenesis, whereas VEGF-B triggers angiogenesis only weakly. Through domain swapping experiments, Anisimov et al . determined that the angiogenic activity of PlGF was conferred by a domain in PlGF that interacted with VEGFR-1, whereas the corresponding domain in VEGF-B did not. These results shed light on the mechanism of receptor activation by VEGF ligands and may help in designing chimeric proteins that could be used therapeutically to promote or inhibit angiogenesis.