New cardiac expression of two adenosine-2A receptor isoforms in dysfunctioning minipigs

Area of Science:

• Cardiovascular Physiology
• Molecular Biology
• Pharmacology

Background:

• Adenosine A2A receptors (A2A R) have known variants in humans, but isoforms in pigs are uncharacterized.
• Understanding cardiac A2A R is crucial for defining its role in cardiovascular pathophysiology.

Purpose of the Study:

• To investigate the presence and characteristics of A2A R isoforms in pig cardiac tissue.
• To explore the potential involvement of A2A R in cardiovascular pathophysiology, particularly in the context of left ventricular dysfunction (LVD).

Main Methods:

• Induction of LVD in minipigs via right ventricular pacing.
• Collection of cardiac tissue from paced and sham-operated pigs.
• Real-Time PCR and Sanger sequencing to identify A2A R isoforms.
• Histological analysis to examine cardiac tissue morphology.

Main Results:

• Two A2A R isoforms (long and short) were detected in pig cardiac tissue.
• A short A2A R isoform with an alternative promoter and specific translated protein was found predominantly near the pacing site in LVD pigs.
• Histology revealed prominent Purkinje cells in the affected cardiac regions of LVD pigs.

Conclusions:

• The presence of distinct A2A R isoforms in pig myocardium suggests state-specific expression.
• These findings highlight the potential differential role of A2A R isoforms in cardiac function and disease.