Palmer, Lisa Ann PhD
Principal Investigator, TITUS Group Project 2
Associate Professor, Pediatrics and Anesthesiology
University of Virginia
Since my arrival at the University of Virginia in 1995, I have been working on the regulation of nitric oxide synthases and nitric oxide signaling pathways. As activation of any one of the nitric oxide synthases correlates with the production of protein S-nitrosothiols, my familiarity with the biological, molecular, and signaling aspects of this enzyme system will be a benefit. In addition, I am proficient in all of the technical aspects of measuring, characterizing, and modulating S-nitrosothiols in vivo, ex vivo and in vitro. I have an excellent working relationship with Dr. Zaman. In fact, we meet regularly to discuss current topics in S-nitrosothiol research, recent advances in the field, current research results and future projects. I will consult and help perform experiments, particularly in the field of molecular biology. In addition, I will review prepared manuscripts.
Dysregulated S-nitrosothiol (SNO) signaling contributes to a wide range of human pathologies including those within the cardiovascular, pulmonary, musculoskeletal, and neurological systems. SNOs have been implicated in the development of various pulmonary diseases, many of which display distinct gender preferences in presentation or a change in severity at puberty by unknown mechanisms. Project 2 examines the hypothesis that S-nitrosothiol bioavailability in the pulmonary vascular endothelium is regulated by a novel hormonally regulated S-nitrosylation/denitrosylation coupling loop. This feedback loop consists of eNOS, which is up-regulated by estrogens, and GSNO-R, which is down-regulated by androgens.
We hypothesize that a mismatch between the production and the catabolism of S-nitrosothiols may contribute to the development of diseases with a gender prediliction such as pulmonary hypertension. However, it may also be applicable to the gender discordance seen in asthma, cystic fibrosis, septic shock, some forms of cancer, cardiovascular disease, and ventilatory control in response to hypoxia. Currently, the impact of the interaction between eNOS and GSNOR, its effect on SNO bioavailability and effects on pulmonary physiology and pathology is currently unknown. Thus, defining the subcellular location of this interaction within the endothelial cell and the influence of this relationship on local SNO abundance is of paramount importance to identifying its role in normal pulmonary vascular physiology and pathology.
Specific Aim 1 examines the hypothesis that crosstalk between GSNO-R and eNOS contributes to S-nitrosothiol bioavailability/ bioactivity seen in the pulmonary endothelium.
A. Define the relationship between eNOS and GSNO-R
B. Determine the differential kinetics of S-nitrosylation of eNOS and GSNO-R
C. Identify the domains/cysteine residues important to GSNO-R and eNOS interaction
Specific Aim 2 examines the hypothesis that the subcellular location of the interaction between eNOS and GSNO-R determines its function within the endothelial cell.
A. Identify the subcellular location where the interaction takes place.
B. Determine the influence of eNOS/GSNO-R crosstalk on the S-nitrosylation and activity of proteins involved in intracellular transport of eNOS.
Specific Aim 3 examines the hypothesis that disruption of the S-nitrosylation/Denitrosylation regulatory loop in the endothelium contributes to the gender preferences in pulmonary arterial hypertension.
A. Determine the expression, location and activities of GSNO-R in male and female mice.
B. Determine changes in the eNOS/GSNO-R coupling with stimuli known to induce pulmonary hypertension.
C. Identify the involvement of sex hormones in determining of S-nitrosothiol bioavailability through the eNOS GSNO-R regulatory couple.