A novel peptide that improves metabolic parameters without adverse central nervous system effects

Area of Science:

• Pharmacology
• Molecular Biology
• Endocrinology

Background:

• Intracellular peptides from proteolysis may have therapeutic potential.
• G-protein coupled receptors (GPCRs) are targets for drug discovery.
• Cannabinoid type 1 receptors (CB1Rs) are involved in metabolic regulation.

Purpose of the Study:

• To screen for novel pharmacologically active peptides targeting GPCRs.
• To identify and characterize peptides with activity at CB1Rs.
• To evaluate the therapeutic potential of a novel peptide (Pep19) for obesity and related metabolic disorders.

Main Methods:

• Screening of peptides using conformational-sensitive antibodies against GPCRs.
• Characterization of peptide activity at CB1Rs, including inverse agonism.
• In vitro studies on adipocytes to assess signaling pathways (pERK1/2, AKT) and gene expression (uncoupling protein 1).
• In vivo studies in diet-induced obese rats to evaluate metabolic effects and safety.
• Assessment of central nervous system effects through behavioral tests and c-Fos expression.

Main Results:

• A peptide, DITADDEPLT, was found to activate CB1Rs.
• A modified peptide, DIIADDEPLT (Pep19), exhibited inverse agonist activity at CB1Rs.
• Pep19 induced uncoupling protein 1 expression in adipose tissue and adipocytes, activating pERK1/2 and AKT pathways.
• Oral Pep19 administration in obese rats reduced adiposity, body weight, glucose, lipids, and blood pressure.
• Pep19 demonstrated no central nervous system effects, indicating peripheral action.

Conclusions:

• Pep19 is a novel peripherally acting CB1R inverse agonist with significant anti-obesity effects.
• Pep19 modulates adipocyte function and metabolic parameters.
• The lack of central nervous system effects makes Pep19 a promising candidate for clinical development in metabolic diseases.