Rational design of highly stabilized and selective adrenomedullin analogs.

Area of Science:

• Medicinal Chemistry
• Pharmacology
• Biochemistry

Background:

• Adrenomedullin (ADM) is a peptide hormone with significant vasodilatory and cardioprotective properties.
• The therapeutic potential of ADM is limited by its poor metabolic stability and rapid degradation in vivo.
• Previous ADM analogs exhibited reduced receptor activity and selectivity for the adrenomedullin 1 receptor (AM1R).

Purpose of the Study:

• To rationally design and develop novel ADM derivatives with enhanced proteolytic stability and improved receptor selectivity.
• To create ADM analogs that retain high agonistic activity at the AM1R while maintaining selectivity over the related calcitonin gene-related peptide receptor (CGRPR).
• To achieve long-term in vivo efficacy for potential therapeutic applications.

Main Methods:

• Rational design incorporating stabilizing motifs such as lactamization, lipidation, and oligoethylene glycol linkers.
• Solid-phase peptide synthesis (Fmoc/t-Bu) for analog preparation.
• In vitro assays including cAMP reporter gene assay for receptor activation (AM1R and CGRPR), and stability testing in human plasma and liver homogenate.
• Analysis of peptide stability and integrity using RP-HPLC and MALDI-ToF mass spectrometry.
• In vivo evaluation of vasodilatory effects in rodent models.

Main Results:

• Novel ADM analogs were synthesized combining lactamization, lipidation, ethylene glycol linkers, and a disulfide mimetic.
• These stabilized analogs demonstrated remarkable proteolytic resistance, with a plasma half-life exceeding 144 hours.
• The developed compounds exhibited excellent AM1R activity and wild-type-like selectivity against CGRPR.
• In vivo studies showed dose-dependent, prolonged vasodilatory effects lasting several hours in rodents.

Conclusions:

• The rational design approach successfully yielded highly stabilized ADM analogs with significantly improved pharmacokinetic profiles.
• These novel ADM derivatives possess potent and selective AM1R agonistic activity, coupled with sustained in vivo efficacy.
• The developed ADM analog represents a promising therapeutic candidate for conditions requiring long-term vasodilation.