Angiogenesis is the process of growing blood vessels in different body organs. Sustainability of life depends on the accuracy and abundance of this process. The cornea is a living tissue that is free of blood vessels, demonstrated by its transparency for optical clarity. The avascularity of the cornea makes it a good model to study the mechanisms that promote or inhibit angiogenesis. By comparing corneal tissue with other vascular tissues, a greater understanding of angiogenesis will occur that will eventually lead to treatment of vascular diseases such as macular degeneration, tumors, or ischemic heart disease.
Angiogenesis is primarily controlled by vascular endothelial growth factor (VEGF) which interacts with tyrosine kinase receptors VEGFR1, VEGFR2 and VEGFR3. Growth of blood vessels occurs when the body secretes VEGF to bind to the receptors and initializes the process. The cornea expresses the soluble version of VEGFR1, which sequesters VEGF, making angiogenesis impossible. However, factors such as injury or stress remove these soluble proteins and blood vessels begin to grow as a recovery response. The ability to induce and observe corneal neovascularization is a valuable tool in studying angiogenesis. Observing the effects of VEGF receptors and other factors that interact with VEGF is crucial to the understanding of angiogenic processes; this information can later be used to treat vascular diseases.
The ultimate goal of this research project is to understand the specifics of VEGF and its receptors to be able to eventually prevent neovascularization. Receptors can be physically altered, which allows for more versatility in research. VEGF specifically binds to domains 2 and 3 of both VEGFR1 and VEGFR2. However, VEGFR1 (also known as Flt-1) is the most abundant of the receptors, so it will be more easily targeted and researched. This means that a total loss in vascularization is not expected, as a reduction will be more likely to occur.
Focusing on the Flt23K receptor (FLT domains 2 and 3 tagged to KDEL protein) will lead to a better understanding of this mechanism. Flt23K is able to bind and sequester VEGF to render it incapable of angiogenesis. The delivery and long term incorporation of this gene is a major hurdle, as past experiments have been shown to be effective but temporary. My hypothesis is that incorporation of the Flt23K gene directly into the genome using a piggyBac plasmid will lead to long term reduction of corneal neovascularization in response to an injury. This will be done by first constructing a plasmid that will insert itself into the genome of a mouse cornea. Mechanical trauma will be induced in order to promote neovascularization. After a biological response has been able to take place, the cornea will be harvested and measured for levels of VEGF and other factors that are related to angiogenesis.
By using the piggyBac method, a plasmid will be created to transpose into a host...