Chronic liver disease leads to ~2 million deaths annually. Cyclic AMP (cAMP) signaling has long been studied in liver injury, particularly in the regulation of fatty acid (FA) β-oxidation and pro-inflammatory polarization of tissue-resident lymphocytes. Phosphodiesterase 4B inhibition has been explored as a therapeutic modality, but these drugs have had limited success and are known to cause significant adverse effects. The PDE4 inhibitor 2-(4-([2-(5-Chlorothiophen-2-yl)-5-ethyl-6-methylpyrimidin-4-yl]amino)phenyl)acetic acid) (known as A-33) has yet to be explored for the treatment of metabolic diseases.
