Albendazole inhibits endothelial cell migration, tube formation, vasopermeability, VEGF receptor-2 expression and suppresses retinal neovascularization in ROP model of angiogenesis

The angiogenic process begins with the cell proliferation and migration into the primary vascular network, and leads to vascularization of previously avascular tissues and organs as well to growth and remodeling of the initially homogeneous capillary plexus to form a new microcirculation. Additionally, an increase in microvascular permeability is a crucial step in angiogenesis. Vascular endothelial growth factor (VEGF) plays a central role in angiogenesis. We have previously reported that albendazole suppresses VEGF levels and inhibits malignant ascites formation, suggesting a possible effect on angiogenesis. This study was therefore designed to investigate the antiangiogenic effect of albendazole in non-cancerous models of angiogenesis. In vitro, treatment of human umbilical vein endothelial cells (HUVECs) with albendazole led to inhibition of tube formation, migration, permeability and down-regulation of the VEGF type 2 receptor (VEGFR-2). In vivo albendazole profoundly inhibited hyperoxia-induced retinal angiogenesis in mice. These results provide new insights into the antiangiogenic effects of albendazole.     

Suppression of vascular permeability and inflammation by targeting of the transcription factor c-Jun

Conventional anti-inflammatory strategies induce multiple side effects, highlighting the need for novel targeted therapies. Here we show that knockdown of the basic-region leucine zipper protein, c-Jun, by a catalytic DNA molecule, Dz13, suppresses vascular permeability and transendothelial emigration of leukocytes in murine models of vascular permeability, inflammation, acute inflammation and rheumatoid arthritis. Treatment with Dz13 reduced vascular permeability due to cutaneous anaphylactic challenge or VEGF administration in mice. Dz13 also abrogated monocyte-endothelial cell adhesion in vitro and abolished leukocyte rolling, adhesion and extravasation in a rat model of inflammation. Dz13 suppressed neutrophil infiltration in the lungs of mice challenged with endotoxin, a model of acute inflammation. Finally, Dz13 reduced joint swelling, inflammatory cell infiltration and bone erosion in a mouse model of rheumatoid arthritis. Mechanistic studies showed that Dz13 blocks cytokine-inducible endothelial c-Jun, E-selectin, ICAM-1, VCAM-1 and VE-cadherin expression but has no effect on JAM-1, PECAM-1, p-JNK-1 or c-Fos. These findings implicate c-Jun as a useful target for anti-inflammatory therapies.     

PDGF-D Expression Is Down-Regulated by TGFβ in Fibroblasts

Transforming growth factor-β (TGFβ) is a key mediator of fibrogenesis. TGFβ is overexpressed and activated in fibrotic diseases, regulates fibroblast differentiation into myofibroblasts and induces extracellular matrix deposition. Platelet-derived growth factor (PDGF) is also a regulator of fibrogenesis. Some studies showed a link between TGFβ and PDGF in certain fibrotic diseases. TGFβ induces PDGF receptor alpha expression in scleroderma fibroblasts. PDGF-C and -D are the most recently discovered ligands and also play a role in fibrosis. In this study, we report the first link between TGFβ and PDGF-D and -C ligands. In normal fibroblasts, TGFβ down-regulated PDGF-D expression and up-regulated PDGF-C expression at the mRNA and protein levels. This phenomenon is not limited to TGFβ since other growth factors implicated in fibrosis, such as FGF, EGF and PDGF-B, also regulated PDGF-D and PDGF-C expression. Among different kinase inhibitors, only TGFβ receptor inhibitors and the IκB kinase (IKK) inhibitor BMS-345541 blocked the effect of TGFβ. However, activation of the classical NF-κB pathway was not involved. Interestingly, in a model of lung fibrosis induced by either bleomycin or silica, PDGF-D was down-regulated, which correlates with the production of TGFβ and other fibrotic growth factors. In conclusion, the down-regulation of PDGF-D by TGFβ and other growth factors may serve as a negative feedback in the network of cytokines that control fibrosis.     

ERK,JNK, and p38 MAP kinases differentially regulate proliferation and migration of phenotypically distinct smooth muscle cell subtypes

Proliferation and migration of vascular smooth muscle cells (SMCs) are important processes involved in the pathogenesis of vascular disorders such as atherosclerosis and post-angioplasty restenosis. Here we demonstrate that proliferation and migration of specific SMC subtypes is mitogen-activated protein (MAP) kinase-dependent. WKY12-22 SMCs derived from the aortae of 12 day-old pup rats proliferate and migrate faster than WKY3M-22 SMCs derived from the aortae of adult rats. WKY12-22 and WKY3M-22 cells equally expressed the active forms of phospho (Thr(183)/Tyr(185))-c-Jun N-terminal kinase (JNK) and phospho (Tyr(182))-p38, whereas the activity of extracellular signal-regulated kinase (ERK) was greater in WKY12-22 cells compared with WKY3M-22 cells. Proliferation of both SMC subtypes was attenuated by PD98059, SP600125 and SB202190, inhibitors of ERK, JNK, and p38, respectively. However, inhibition of PD98059 had a more profound effect on WKY12-22 SMCs. Furthermore, migration of WKY12-22 and WKY3M-22 cells was inhibited by SP600125 and SB202190, however, PD98059 failed to influence migration of either SMC subtype. Hence, migration of both SMC subtypes is JNK- and p38-dependent, but not ERK-dependent. These findings demonstrate that SMC heterogeneity is mediated, at least in part, by the activity of specific MAP kinase subtypes.