Related Experiment Video
Updated: Jul 30, 2026
Megakaryocyte Differentiation and Platelet Formation from Human Cord Blood-derived CD34+ Cells
Published on: December 27, 2017
Molecular cloning and characterization of the platelet-activating factor receptor gene expressed in the human heart
T Sugimoto1, H Tsuchimochi, C G McGregor
1Department of Internal Medicine, Mayo Clinic, Mayo Foundation, Rochester, MN 55905.
Insights
Researchers identified a cardiac Platelet-Activating Factor (PAF) receptor in human heart tissue. This finding suggests a novel mechanism for regulating PAF receptor expression in the heart.
Area of Science:
- Cardiovascular Biology
- Molecular Pharmacology
- Receptor Biology
Background:
- Platelet-Activating Factor (PAF) is known to reduce cardiac contractility and blood pressure.
- Understanding the cardiac PAF receptor is crucial for elucidating PAF's cardiovascular effects.
Purpose of the Study:
- To identify and characterize the PAF receptor in human ventricular tissue.
- To investigate potential tissue-specific regulation of PAF receptor expression.
Main Methods:
- Screening of a human ventricular cDNA library using a probe for the guinea pig lung PAF receptor.
- Functional expression studies in Xenopus oocytes to assess PAF-induced currents.
- Northern blot analysis of human cardiac tissues to determine mRNA size.
Main Results:
- Four cDNA clones (HV1-4) were isolated; HV3 and HV4 encoded the human leukocyte PAF receptor.
- PAF stimulation of Xenopus oocytes expressing HV3 or HV4 cRNA induced Ca(2+)-activated Cl- currents.
- Northern blotting revealed a ~4 kb mRNA band in human ventricles and atria, suggesting a specific transcript size.
Conclusions:
- A cardiac PAF receptor, identical to the leukocyte receptor polypeptide, was identified.
- Differences in the 5' untranslated region of HV3/4 compared to the leukocyte receptor suggest regulatory mechanisms.
- Results indicate a potential tissue-specific translational regulation of cardiac PAF receptor mRNA expression.
Abstract:
PAF decreases cardiac contractility and blood pressure. To characterize the cardiac PAF receptor, we screened a human ventricular cDNA library in a low stringency condition, using a PCR product derived from guinea pig lung PAF receptor as a probe. Four clones were obtained and named HV1-4. In Xenopus oocytes injected with cRNA derived from HV3 or 4 but not from HV1 or 2, PAF elicited a Ca(2+)-activated Cl- current. HV3 and HV4 were duplicate clones, encoding a 342 amino-acid polypeptide which was identical to that of the human leukocyte PAF receptor. However, a portion of the 5' untranslated region of HV3 (or 4) was different from that of the leukocyte receptor cDNA. Northern blotting of human ventricles and atria using the HV3 insert showed a single band of approximately 4 kb. These results suggest a tissue-specific translational mechanism responsible for regulation of the expression of the PAF receptor mRNA in these tissues.
