LPAR1 and obesity due to melanocortin 4 receptor deficiency: Despite recent studies implicating LPA receptor signaling in cardiovascular disease [9–13] and obesity/diabetes [20, 22–24, 30–32], it remains unclear which of the six so far identified LPA receptors (LPA1-6) are expressed in the heart and cardiomyocytes and whether myocardial LPA receptor expression is regulated by changes in metabolic status.