GPRC Function in autophagy control: a systematic approach of chemical intervention

Autophagy facilitates the degradation of cellular content via the lysosome and is involved in cellular homeostasis and stress response pathways. As such, malfunction of autophagy is linked to a variety of diseases ranging from organ specific illnesses like cardiomyopathy to systemic illnesses such as cancer or metabolic syndromes. Given the variety of autophagic functions within a cell and tissue, regulation of autophagy is complex and contains numerous positive and negative feedback loops. While our knowledge of mechanisms for cargo selectivity has significantly improved over the last decade, our understanding of signaling routes activating individual autophagy pathways remains rather sparce. In this resource study, we report on a well-characterized chemical library assembled within the IMI initiative EUbOPEN containing 77 GPCR-targeting ligands that was used to systematically analyze LC3B-based autophagy as well as ER-phagy flux upon compound treatment. The global impact of hit compounds TC-G 1004, BAY 60-6583, PSNCBAM-1, TC-G 1008, LPA2 Antagonist 1, ML154, JTC-801 and ML-290 targeting Adenosine receptor A2a (ADORA2A), Adenosine receptor A2b (ADORA2B), Cannabinoid receptor 1 (CNR1), G-protein coupled receptor 39 (GPR39), Lysophosphatidic acid receptor 2 (LPAR2), neuropeptide S receptor 1 (NPSR1), NOP (OPRL1), and Relaxin receptor 1 (RXFP1) were subsequently analyzed and compared by TMT-based mass spectrometry. Our results indicate the differential impact of targeted GPCRs on known autophagy-associated proteins.