Barbara Meyrick, Ph.D.
Vanderbilt University Medical Center, Nashville, TN
Proteomic Approach to Unravelling the Pathogenesis of IPAH.
Diverse germline heterozygous mutations in the bone morphogenetic protein receptor type II (BMPR2) gene have been demonstrated in the majority of patients with familial pulmonary artery hypertension (FPAH) and approximately 25% sporadically affected subjects (IPAH). Since not all persons with mutations in BMPR2 develop the disease, our first hypothesis is that full expression of FPAH is accompanied by alterations in expression of one or a series of proteins as well as mutations in the BMPR2 gene.
The search for modifier genes and proteins in FPAH and for a protein marker(s) associated with the pathogenesis of IPAH is complex and to date only a few putative marker proteins have been examined. Application of proteomic techniques allows numerous proteins to be assessed at one time and is likely to hasten the finding of modifier proteins. Use of proteomic techniques will also allow us to answer our second hypothesis - that alterations in expression of specific proteins will serve as a marker of patients at risk for developing IPAH in the absence of a BMPR2 mutation.
Four specific aims address our two interrelated hypotheses:
1.) Determine the differences in protein profiles of pulmonary arteries displaying the various structural changes of IPAH as compared to each other and to similarly sized control arteries.
2.) Determine whether the protein profiles of various structural lesions are different in patients with IPAH with and without mutations in BMPR2 as well as in patients with FPAH.
3.) Search for a protein marker for IPAH by comparing the protein profiles from transformed lymphocytes isolated from patients with IPAH and controls.
4.) Search for a modifier protein in families with BMPR2 mutations using transformed lymphocytes from individuals with overt FPAH and those without evidence of disease. These aims will be addressed using laser capture microscopy, MALDI-TOF MS profiling and 2D-Differential Gel Electrophoresis. These studies will be carried out using the Vanderbilt Mass Spectrometry Research Center and its Tissue Profiling Laboratory of which Dr. Richard Caprioli is the Director.
If successful, the proposed studies will identify a protein(s) that can be used to identify patients with a BMPR2 mutation that are at risk for developing FPAH and to identify patients at risk for developing IPAH in the absence of a mutations in the BMPR2 gene. Identification of a specific protein or a group of proteins may also provide a target for novel therapeutic approaches.