The proposed project will focus on the role of fibroblast growth factors (FGFs) in the control of proliferation and differentiation in vascular smooth muscle cells. The overall goal of the project is to determine if endogenously synthesized FGFs participate in regulating these processes, and if so, whether they produce their effects primarily through interactions with cell surface receptors activating cytoplasmic second messenger pathways, or directly in the nucleus via regulated patterns of intracellular trafficking (or both). By manipulating FGF expression, the role of endogenously produced FGFs in smooth muscle proliferation and differentiation will be determined. The signaling pathway(s) (nuclear or cytoplasmic) utilized to mediate the effects of extracellular and intracellular FGF will be investigated. Mutational analysis will be used to identify the signals responsible for cellular trafficking of FGFs, and the synthesis of FGF/reporter fusion proteins will allow cellular localization to be monitored. The effect of extracellularly produced FGF isoforms and mutant proteins, as well as FGF receptor isoforms and mutants, on the proliferation and differentiation of smooth muscle cells will be examined to identify functional domains of these proteins and to probe the mechanisms responsible for their effects. The applicant's research interests include the molecular mechanisms of vascular, skeletal and cardiac muscle development related to the control of cellular proliferation and differentiation. The disease processes of atherogenesis, restenosis following mechanical revascularization, cardiac hypertrophy, myocardial remodeling after infarction, congenital cardiac malformations, and skeletal muscle regeneration or degeneration each involve basic mechanisms controlling the proliferation of, and expression of differentiation-specific genes in, muscle cells. A better understanding of the effects of FGFs on myogenic differentiation, and the pathways responsible for FGF signaling, is of general importance since this knowledge may be useful in developing strategies to influence muscle development and alter the course of muscular diseases. The preceptor's area of research is of particular interest to the applicant because of the potential relationship between a better understanding of myogenesis and novel therapeutic approaches to ischemic cardiovascular disease. The preceptor's laboratory is experienced in the techniques of interest to the applicant, including cell culture, gene cloning and in vitro or in vivo means of assessing gene expression. The availability of a bank of cloned muscle-related gene sequences will allow the detailed assessment of the functional consequences resulting form manipulation of FGFs in cultured smooth muscle cells. Several aspects of the proposed project may be amenable to analysis using transgenic models in collaboration with other members of the research group focusing on such models. Participating in the intellectual environment and acquiring the technological skills as currently practiced in the preceptor's laboratory will give the applicant a solid foundation upon which to build an independent research program in molecular cardiology.