Limits...
Imatinib inhibits VEGF-independent angiogenesis by targeting neuropilin 1-dependent ABL1 activation in endothelial cells.

Raimondi C, Fantin A, Lampropoulou A, Denti L, Chikh A, Ruhrberg C - J. Exp. Med. (2014)

Bottom Line: NRP1 formed a complex with ABL1 that was responsible for FN-dependent PXN activation and actin remodeling.Accordingly, both physiological and pathological angiogenesis in the retina were inhibited by treatment with Imatinib, a small molecule inhibitor of ABL1 which is widely used to prevent the proliferation of tumor cells that express BCR-ABL fusion proteins.The finding that NRP1 regulates angiogenesis in a VEGF- and VEGFR2-independent fashion via ABL1 suggests that ABL1 inhibition provides a novel opportunity for anti-angiogenic therapy to complement VEGF or VEGFR2 blockade in eye disease or solid tumor growth.

View Article: PubMed Central - HTML - PubMed

Affiliation: UCL Institute of Ophthalmology, University College London, London EC1V 9EL, England UK c.raimondi@ucl.ac.uk c.ruhrberg@ucl.ac.uk.

Show MeSH

Related in: MedlinePlus

Imatinib and endothelial NRP1 targeting inhibit pathological angiogenesis in mouse models of retinopathy and ear wound healing. (A) Immunostaining of a P17 wild-type mouse retina for FN together with IB4 after sequential exposure to 7 d of normoxia, 5 d of hyperoxia, and 5 d of normoxia. The area indicated with a square is shown in higher magnification adjacent to the first panel as double label and single channels. Bar, 1 mm. (B) Immunostaining for collagen IV together with IB4 of P17 retinas from mice treated with vehicle (control) or Imatinib by daily injections after return from hyperoxia to normoxia (P13–16). Pseudocoloring highlights AV (white) and neovascularization (NV, red). Bar, 1 mm. (C–F) Quantitation of AV and NV area in Imatinib-treated relative to vehicle-injected littermates (C and D; fold change; n = 8 retinas each) and in tamoxifen-injected Nrp1fl/fl mice lacking or expressing Pdgfb-iCre-ERT2-Egfp (E and F; fold change; n ≥ 5 retinas each). Asterisks indicate statistical significance: *, P < 0.05; **, P < 0.01; ***, P < 0.001, Student’s t test. Error bars show SD. (G–J) To examine angiogenesis-dependent wound healing in the ear of vehicle- and Imatinib-treated mice between the day of injury (day 0, D0) and day 21, the punch wound was imaged on days 0 and 21 (G; bar, 2 mm) and immunostained for FN together with PECAM and DAPI in 40-µm ear sections on day 21 (H and I; bar, 200 µm). Higher magnifications of the areas indicated with dotted squares in H and I are shown in H′ and I′. Note the reduced number of blood vessels at the wound margin after Imatinib treatment (Δ). (J) Quantitation of wound diameter in vehicle and Imatinib-treated mice on days 0, 7, 14, and 21 after wounding (vehicle, n = 3 mice; Imatinib, n = 4 mice; *, P < 0.05; **, P < 0.01, Student’s t test for vehicle vs. Imatinib-treated mice at days 14 and 21). Error bars show SEM.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4042645&req=5

fig8: Imatinib and endothelial NRP1 targeting inhibit pathological angiogenesis in mouse models of retinopathy and ear wound healing. (A) Immunostaining of a P17 wild-type mouse retina for FN together with IB4 after sequential exposure to 7 d of normoxia, 5 d of hyperoxia, and 5 d of normoxia. The area indicated with a square is shown in higher magnification adjacent to the first panel as double label and single channels. Bar, 1 mm. (B) Immunostaining for collagen IV together with IB4 of P17 retinas from mice treated with vehicle (control) or Imatinib by daily injections after return from hyperoxia to normoxia (P13–16). Pseudocoloring highlights AV (white) and neovascularization (NV, red). Bar, 1 mm. (C–F) Quantitation of AV and NV area in Imatinib-treated relative to vehicle-injected littermates (C and D; fold change; n = 8 retinas each) and in tamoxifen-injected Nrp1fl/fl mice lacking or expressing Pdgfb-iCre-ERT2-Egfp (E and F; fold change; n ≥ 5 retinas each). Asterisks indicate statistical significance: *, P < 0.05; **, P < 0.01; ***, P < 0.001, Student’s t test. Error bars show SD. (G–J) To examine angiogenesis-dependent wound healing in the ear of vehicle- and Imatinib-treated mice between the day of injury (day 0, D0) and day 21, the punch wound was imaged on days 0 and 21 (G; bar, 2 mm) and immunostained for FN together with PECAM and DAPI in 40-µm ear sections on day 21 (H and I; bar, 200 µm). Higher magnifications of the areas indicated with dotted squares in H and I are shown in H′ and I′. Note the reduced number of blood vessels at the wound margin after Imatinib treatment (Δ). (J) Quantitation of wound diameter in vehicle and Imatinib-treated mice on days 0, 7, 14, and 21 after wounding (vehicle, n = 3 mice; Imatinib, n = 4 mice; *, P < 0.05; **, P < 0.01, Student’s t test for vehicle vs. Imatinib-treated mice at days 14 and 21). Error bars show SEM.

Mentions: To assess the relevance of the FN-induced NRP1–ABL1 pathway for pathological vessel growth, we used a mouse model of oxygen-induced retinopathy (OIR; Connor et al., 2009). In this model, the sequential exposure of mouse pups to hyperoxia followed by normoxia leads to the formation of retinal neovascular lesions that resemble those observed in PDR patients and in babies with ROP, which arises after moving them out of incubators with high oxygen tension (Connor et al., 2009). Specifically, the exposure of neonatal mice to hyperoxia from P7 to P12 induces vasoobliteration of central retinal capillaries, which causes central retinal hypoxia on return to room air. The ensuing up-regulation of VEGF and other proangiogenic factors then activates angiogenesis, but this process fails to effectively revascularize the retina and instead leads to abundant tuft-like vascular malformations that protrude into the vitreous (Smith et al., 1994). Immunostaining of flat-mounted retinas on P17, 5 days after return to room air, showed that these neovascular tufts were FN positive (Fig. 8 A), suggesting that OIR is a suitable model to examine the role of NRP1 and ABL1 in ECM-mediated angiogenesis pathways. In agreement, Imatinib treatment of mouse pups from their return to normoxia until P17 significantly reduced revascularization of avascular areas (AV; Fig. 8, B and C) and effectively inhibited the formation of neovascular tufts (Fig. 8, B–D).


Imatinib inhibits VEGF-independent angiogenesis by targeting neuropilin 1-dependent ABL1 activation in endothelial cells.

Raimondi C, Fantin A, Lampropoulou A, Denti L, Chikh A, Ruhrberg C - J. Exp. Med. (2014)

Imatinib and endothelial NRP1 targeting inhibit pathological angiogenesis in mouse models of retinopathy and ear wound healing. (A) Immunostaining of a P17 wild-type mouse retina for FN together with IB4 after sequential exposure to 7 d of normoxia, 5 d of hyperoxia, and 5 d of normoxia. The area indicated with a square is shown in higher magnification adjacent to the first panel as double label and single channels. Bar, 1 mm. (B) Immunostaining for collagen IV together with IB4 of P17 retinas from mice treated with vehicle (control) or Imatinib by daily injections after return from hyperoxia to normoxia (P13–16). Pseudocoloring highlights AV (white) and neovascularization (NV, red). Bar, 1 mm. (C–F) Quantitation of AV and NV area in Imatinib-treated relative to vehicle-injected littermates (C and D; fold change; n = 8 retinas each) and in tamoxifen-injected Nrp1fl/fl mice lacking or expressing Pdgfb-iCre-ERT2-Egfp (E and F; fold change; n ≥ 5 retinas each). Asterisks indicate statistical significance: *, P < 0.05; **, P < 0.01; ***, P < 0.001, Student’s t test. Error bars show SD. (G–J) To examine angiogenesis-dependent wound healing in the ear of vehicle- and Imatinib-treated mice between the day of injury (day 0, D0) and day 21, the punch wound was imaged on days 0 and 21 (G; bar, 2 mm) and immunostained for FN together with PECAM and DAPI in 40-µm ear sections on day 21 (H and I; bar, 200 µm). Higher magnifications of the areas indicated with dotted squares in H and I are shown in H′ and I′. Note the reduced number of blood vessels at the wound margin after Imatinib treatment (Δ). (J) Quantitation of wound diameter in vehicle and Imatinib-treated mice on days 0, 7, 14, and 21 after wounding (vehicle, n = 3 mice; Imatinib, n = 4 mice; *, P < 0.05; **, P < 0.01, Student’s t test for vehicle vs. Imatinib-treated mice at days 14 and 21). Error bars show SEM.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4042645&req=5

fig8: Imatinib and endothelial NRP1 targeting inhibit pathological angiogenesis in mouse models of retinopathy and ear wound healing. (A) Immunostaining of a P17 wild-type mouse retina for FN together with IB4 after sequential exposure to 7 d of normoxia, 5 d of hyperoxia, and 5 d of normoxia. The area indicated with a square is shown in higher magnification adjacent to the first panel as double label and single channels. Bar, 1 mm. (B) Immunostaining for collagen IV together with IB4 of P17 retinas from mice treated with vehicle (control) or Imatinib by daily injections after return from hyperoxia to normoxia (P13–16). Pseudocoloring highlights AV (white) and neovascularization (NV, red). Bar, 1 mm. (C–F) Quantitation of AV and NV area in Imatinib-treated relative to vehicle-injected littermates (C and D; fold change; n = 8 retinas each) and in tamoxifen-injected Nrp1fl/fl mice lacking or expressing Pdgfb-iCre-ERT2-Egfp (E and F; fold change; n ≥ 5 retinas each). Asterisks indicate statistical significance: *, P < 0.05; **, P < 0.01; ***, P < 0.001, Student’s t test. Error bars show SD. (G–J) To examine angiogenesis-dependent wound healing in the ear of vehicle- and Imatinib-treated mice between the day of injury (day 0, D0) and day 21, the punch wound was imaged on days 0 and 21 (G; bar, 2 mm) and immunostained for FN together with PECAM and DAPI in 40-µm ear sections on day 21 (H and I; bar, 200 µm). Higher magnifications of the areas indicated with dotted squares in H and I are shown in H′ and I′. Note the reduced number of blood vessels at the wound margin after Imatinib treatment (Δ). (J) Quantitation of wound diameter in vehicle and Imatinib-treated mice on days 0, 7, 14, and 21 after wounding (vehicle, n = 3 mice; Imatinib, n = 4 mice; *, P < 0.05; **, P < 0.01, Student’s t test for vehicle vs. Imatinib-treated mice at days 14 and 21). Error bars show SEM.
Mentions: To assess the relevance of the FN-induced NRP1–ABL1 pathway for pathological vessel growth, we used a mouse model of oxygen-induced retinopathy (OIR; Connor et al., 2009). In this model, the sequential exposure of mouse pups to hyperoxia followed by normoxia leads to the formation of retinal neovascular lesions that resemble those observed in PDR patients and in babies with ROP, which arises after moving them out of incubators with high oxygen tension (Connor et al., 2009). Specifically, the exposure of neonatal mice to hyperoxia from P7 to P12 induces vasoobliteration of central retinal capillaries, which causes central retinal hypoxia on return to room air. The ensuing up-regulation of VEGF and other proangiogenic factors then activates angiogenesis, but this process fails to effectively revascularize the retina and instead leads to abundant tuft-like vascular malformations that protrude into the vitreous (Smith et al., 1994). Immunostaining of flat-mounted retinas on P17, 5 days after return to room air, showed that these neovascular tufts were FN positive (Fig. 8 A), suggesting that OIR is a suitable model to examine the role of NRP1 and ABL1 in ECM-mediated angiogenesis pathways. In agreement, Imatinib treatment of mouse pups from their return to normoxia until P17 significantly reduced revascularization of avascular areas (AV; Fig. 8, B and C) and effectively inhibited the formation of neovascular tufts (Fig. 8, B–D).

Bottom Line: NRP1 formed a complex with ABL1 that was responsible for FN-dependent PXN activation and actin remodeling.Accordingly, both physiological and pathological angiogenesis in the retina were inhibited by treatment with Imatinib, a small molecule inhibitor of ABL1 which is widely used to prevent the proliferation of tumor cells that express BCR-ABL fusion proteins.The finding that NRP1 regulates angiogenesis in a VEGF- and VEGFR2-independent fashion via ABL1 suggests that ABL1 inhibition provides a novel opportunity for anti-angiogenic therapy to complement VEGF or VEGFR2 blockade in eye disease or solid tumor growth.

View Article: PubMed Central - HTML - PubMed

Affiliation: UCL Institute of Ophthalmology, University College London, London EC1V 9EL, England UK c.raimondi@ucl.ac.uk c.ruhrberg@ucl.ac.uk.

Show MeSH
Related in: MedlinePlus