Retinal angiogenesis suppression through small molecule activation of p53
Sai H. Chavala, Younghee Kim, Laura Tudisco, Valeria Cicatiello, Till Milde, Nagaraj Kerur, Nidia Claros, Susan Yanni, Victor H. Guaiquil, William W. Hauswirth, John S. Penn, Shahin Rafii, Sandro De Falco, Thomas C. Lee, Jayakrishna Ambati
Sai H. Chavala, Younghee Kim, Laura Tudisco, Valeria Cicatiello, Till Milde, Nagaraj Kerur, Nidia Claros, Susan Yanni, Victor H. Guaiquil, William W. Hauswirth, John S. Penn, Shahin Rafii, Sandro De Falco, Thomas C. Lee, Jayakrishna Ambati
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Research Article Vascular biology

Retinal angiogenesis suppression through small molecule activation of p53

Abstract

Neovascular age-related macular degeneration is a leading cause of irreversible vision loss in the Western world. Cytokine-targeted therapies (such as anti-vascular endothelial growth factor) are effective in treating pathologic ocular angiogenesis, but have not led to a durable effect and often require indefinite treatment. Here, we show that Nutlin-3, a small molecule antagonist of the E3 ubiquitin protein ligase MDM2, inhibited angiogenesis in several model systems. We found that a functional p53 pathway was essential for Nutlin-3–mediated retinal antiangiogenesis and disruption of the p53 transcriptional network abolished the antiangiogenic activity of Nutlin-3. Nutlin-3 did not inhibit established, mature blood vessels in the adult mouse retina, suggesting that only proliferating retinal vessels are sensitive to Nutlin-3. Furthermore, Nutlin-3 inhibited angiogenesis in nonretinal models such as the hind limb ischemia model. Our work demonstrates that Nutlin-3 functions through an antiproliferative pathway with conceivable advantages over existing cytokine-targeted antiangiogenesis therapies.

Authors

Sai H. Chavala, Younghee Kim, Laura Tudisco, Valeria Cicatiello, Till Milde, Nagaraj Kerur, Nidia Claros, Susan Yanni, Victor H. Guaiquil, William W. Hauswirth, John S. Penn, Shahin Rafii, Sandro De Falco, Thomas C. Lee, Jayakrishna Ambati

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Figure 7

Nutlin-3 inhibits postnatal retinal vascular proliferation.

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Nutlin-3 inhibits postnatal retinal vascular proliferation. (A) Postnata...
(A) Postnatal mouse retinal vascular development after birth (upper left panel). The optic nerve (ON) at the center of a retinal whole mount with green arrows indicating the direction of postnatal blood vessel growth (upper middle and right panels). GS-IB4 lectin staining of a retinal whole mount in the developing mouse pup demonstrating radial growth pattern of postnatal development of retinal vasculature. (lower panels). Double asterisks indicate areas of avascular retina. (B and C) Neonatal mice were given subcutaneous injections in the nape. (B) The retinal vasculature is abrogated in the Nutlin-3–treated eyes (n = 6) (bottom row) compared with the sham-injected mice (n = 4) (middle row). In addition, we noticed loss of smaller caliber vessels (inset, right column) in the Nutlin-3–treated mice. (C) The graph represents retinal vasculature measured as a function of pixels compared with the amount of retinal tissue in each mouse eye (*P < 0.05, representative of 2 independent experiments). (D and E) Neonatal mice were injected in the periocular area of each eye. (E) Nutlin-3–treated (lower row) mice (n = 8) have less retinal vasculature compared with sham-injected mice (n = 8) (upper row). (D) Same quantification method used in B shows a statistically significant difference between the 2 groups (*P < 0.01, representative of 2 independent experiments). (F) Rare TUNEL-positive cells identified in the retinal vasculature of a Nutlin-3–treated mouse. Original magnification, ×400. White arrows point to residual fetal vasculature unable to be removed during dissection. Data represent mean ± SD. *P < 0.05. Scale bars: 500 μm.