TLQP 21 (trifluoroacetate salt)

TLQP 21 is a neuropeptide and fragment of the neurosecretory protein VGF (non-acronymic). It is produced by cleavage of pro-VGF by prohormone convertases. TLQP 21 selectively activates the complement C3a receptor (C3aR; EC50 = 83.6 nM in CHO cells expressing the human receptor) over C5a1 and C5a2 at 10 µM and induces phosphorylation of ERK1/2 in primary mouse bone marrow-derived macrophages (BMDMs), which endogenously express C3aR (EC50 = 96.5 nM). It also induces increases in intracellular calcium in primary mouse BMDMs, which can be inhibited by monoclonal antibodies targeting the globular C1q receptor (gC1qR). Intraplantar hind paw injection of TLQP 21-activated macrophages induces mechanical persensitivity in rats. TLQP 21 (25 µg/animal, i.c.v.) decreases food intake and body weight in hamsters. It also increases serum luteinizing hormone (LH) levels in pre-pubertal female rats when administered intraperitoneally but not intracerebroventricularly.