CONTROL ID: 1315075 INHIBITION OF PRE-B CELL COLONY-ENHANCING FACTOR (PBEF) PREVENTS AND REVERSES MONOCROTALINE-INDUCED PULMONARY HYPERTENSION
J. Chen, H. Yamamura, K.M. Shioura, J. Torres, A. Yamamura, S. Sahni, J. Wan, Q. Guo, S.M. Camp, C. Evenoski, Y. Zhao, A. Desai, L. Moreno-Vinasco, J.X. Yuan, J.G. Garcia, R.F. Machado University of Illinois at Chicago, Chicago, IL.
CURRENT CATEGORY: Cardiology/Cardiovascular Disease
ABSTRACT BODY: Rationale: We have previously shown that PBEF, a cytozyme with extracellular proinflammatory cytokine-like activity and intracellular enzymatic activity as a phosphoribosyltransferase, which regulates intracellular NAD levels and cellular redox state, regulates histone deacetylases and inhibits apoptosis, is significantly upregulated in patients with pulmonary arterial hypertension. We sought to determine whether inhibition of the cytokine and enzymatic activities of PBEF could prevent and reverse monocrotaline (MCT)-induced pulmonary hypertension (PH) in rats. In addition, we hypothesized that PBEF could affect calcium signaling pathway, which plays a role in cell proliferation and vascular constriction.
Methods: Male Sprague-Dawley rats (n=6 per group) received one dose of MCT (60mg/kg), IP. In the prevention experiments, rats were simultaneously administrated FK866 (an inhibitor of PBEF enzymatic activity) (2.5 mg/kg, IP, twice daily for 2wks) or recombinant goat anti-PBEF antibodies (20mg/kg, IP, daily for 2wks). In the reversal experiments, the same doses frequency and duration of FK866 or PBEF antibodies were given two weeks after MCT. Right ventricular systolic pressure (RVSP) was determined with a pressure transducer catheter. The right ventricle: left ventricle +septum (RV/LV+S) ratio was calculated. In a cell culture model, human pulmonary arterial smooth muscle cells (PASMC) were stimulated with recombinant PBEF (25ug/ml) for 6 hrs and 48 hrs. [Ca2+]cyt was measured in PASMC loaded with flura-2/AM (4uM) in a fluorescence microscope and cyclepiazonic acid (CPA, a specific Ca2+-ATPase inhibitor) was used to induce store-operated calcium entry (SOCE).
Results: Administration of FK866 or PBEF antibody prevented the development of PH (RVSP (mmHg) 21.04 ± 0.65 [control] vs. 39.33 ± 3.24 …