β‐amino acid analogs of an insect neuropeptide feature potent bioactivity and resistance to peptidase hydrolysis

Abstract

Insect neuropeptides of the insect kinin class share a common C-terminal pentapeptide sequence F(1)X(1)(2)X(2)(3)W(4)G(5)-NH(2) (X(2)(3) = P, S, A) and regulate such critical physiological processes as water balance and digestive enzyme release. Analogs of the insect kinin class, in which the critical residues of F(1), P(3), and W(4) were replaced with beta(3)-amino acid or their beta(2)-homo-amino acid variants, have been synthesized by the solid phase peptide strategy. The resulting single- and double-replacement analogs were evaluated in an insect diuretic assay and enzyme digestion trials. Analogs modified in the core P(3) position produce a potent and efficacious diuretic response that is not significantly different from that obtained with the endogenous achetakinin peptides. The analogs also demonstrate enhanced resistance to hydrolysis by ACE and NEP, endopeptidases that inactivate the natural insect neuropeptides. This paper describes the first instance of beta-amino acids analogs of an arthropod peptide that demonstrate significant bioactivity and resistance to peptidase degradation.

Leucokinin mimetic elicits aversive behavior in mosquito Aedes aegypti (L.) and inhibits the sugar taste neuron

“…Although both the Aib-containing analogs 1728 and 1729 elicit hindgut contractions in Rhodnius; 1728 is more potent (39). Structural modifications of insect kinins, such as the incorporation of Aib and β-amino acids with an additional methylene group (-CH 2 -), render these peptides biostable, because they are protease resistant (8,(10)(11)(12)26). Our hypothesis is that the potent analog 1728 enters the labellar and tarsal sensilla (30) and diffuses through the aqueous sensillum lymph to activate the Aedae-KR expressed in sucrose taste neurons, thereby decreasing sucrose taste perception.…”

“…We verified that the aedeskinins activate the single Aedes kinin receptor (Aedae-KR), a G protein-coupled receptor (GPCR) that signals through intracellular calcium (9). We designed kinin analogs to be resistant to degrading peptidases and therefore exhibit sustained high potency (10,11). One biostable kinin peptidomimetic containing aminoisobutyric acid, 1728, has potency similar to or higher than the aedeskinins on recombinant receptors (12).…”

A SLC4-like anion exchanger from renal tubules of the mosquito (Aedes aegypti): evidence for a novel role of stellate cells in diuretic fluid secretion

“…In other experiments, unstimulated secretion rates were first measured over 30 min, and then aedeskinin III (AKIII) or calcitonin-like peptide from Anopheles gambiae (CLP; Anoga-DH 31) was added to the Ringer droplet to yield a concentration of 10 Ϫ6 M. After secretion rates were measured for 30 min in the presence of AKIII or CLP, DIDS was added to the Ringer droplet at a final concentration of 200 M, and the ensuing secretion rate was measured for 30 min. The AKIII was synthesized and provided by the laboratory of Nachman (97). The CLP was a gift of Prof. David A. Schooley (University of Nevada).…”

Signaling to the apical membrane and to the paracellular pathway: changes in the cytosolic proteome ofAedesMalpighian tubules

“…All aedeskinins were synthesized in the laboratory of Nachman (Zubrzak et al, 2007). The calcitonin-like diuretic peptide AnogaDH31 was a gift of David Schooley (University of Nevada).…”