Orphan GPCR Ligand

Succinate calcium is a key intermediate product of the citric acid cycle (tricarboxylic acid cycle). Succinate calcium can act as a specific ligand for the G protein-coupled receptor GPR91. Succinate calcium can increase the amplitude of calcium transient in cardiac muscle cells and accelerate the decay rate of calcium transient. Succinate calcium can induce myocardial apoptosis.

Phoenixin-14 (PNX-14) TFA is an endogenous neuropeptide with multiple biological activities, and serves as the endogenous ligand of GPR173. Phoenixin-14 TFA reduces ROS production by inhibiting the HMGB1/TLR4/MyD88/NF-κB signaling axis, thereby exerting antioxidant and mitochondrial protective effects. Phoenixin-14 TFA inhibits FOXO3 phosphorylation by upregulating SIRT3 expression, suppresses apoptosis, and improves myocardial systolic/diastolic function. Phoenixin-14 TFA resists ferroptosis by activating the ATF4/SLC7A11/GPX4 axis; it activates ERK1/2 phosphorylation via GPR173. Phoenixin-14 TFA can be used in researches on neuroprotection, diabetes, cardiomyopathy, reproductive protection and so on.