Activation of M1 muscarinic acetylcholine receptors by proline-rich oligopeptide 7a (

Author(s)

Carlos Alberto-Silva ^[1] ; Halyne Queiroz Pantaleão ^[2] ; Brenda Rufino da Silva ^[3] ; Julio Cezar Araujo da Silva ^[4] ; Marcela Bermudez Echeverry ^[5]

Affiliation

^[1] Federal University of ABC. Natural and Humanities Sciences Center. Experimental Morphophysiology Laboratory - Brasil

^[2] Federal University of ABC. Natural and Humanities Sciences Center. Experimental Morphophysiology Laboratory - Brasil

^[3] Federal University of ABC. Natural and Humanities Sciences Center. Experimental Morphophysiology Laboratory - Brasil

^[4] Federal University of ABC. Natural and Humanities Sciences Center. Experimental Morphophysiology Laboratory - Brasil

^[5] Federal University of ABC. Center for Mathematics, Computation and Cognition - Brasil

• Document type: Journal article
• Source: Journal of Venomous Animals and Toxins including Tropical Diseases; v. 30, 2024-02-09.

Abstract

Abstract Background: The bioactive peptides derived from snake venoms of the Viperidae family species have been promising as therapeutic candidates for neuroprotection due to their ability to prevent neuronal cell loss, injury, and death. Therefore, this study aimed to evaluate the cytoprotective effects of a synthetic proline-rich oligopeptide 7a (PRO-7a; <EDGPIPP) from Bothrops jararaca snake, on oxidative stress-induced toxicity in neuronal PC12 cells and astrocyte-like C6 cells. Methods: Both cells were pre-treated for four hours with different concentrations of PRO-7a, submitted to H2O2-induced damage for 20 h, and then the oxidative stress markers were analyzed. Also, two independent neuroprotective mechanisms were investigated: a) L-arginine metabolite generation via argininosuccinate synthetase (AsS) activity regulation to produce agmatine or polyamines with neuroprotective properties; b) M1 mAChR receptor subtype activation pathway to reduce oxidative stress and neuron injury. Results: PRO-7a was not cytoprotective in C6 cells, but potentiated the H2O2-induced damage to cell integrity at a concentration lower than 0.38 μM. However, PRO-7a at 1.56 µM, on the other hand, modified H2O2-induced toxicity in PC12 cells by restoring cell integrity, mitochondrial metabolism, ROS generation, and arginase indirect activity. The α-Methyl-DL-aspartic acid (MDLA) and L-NΩ-Nitroarginine methyl ester (L-Name), specific inhibitors of AsS and nitric oxide synthase (NOS), which catalyzes the synthesis of polyamines and NO from L-arginine, did not suppress PRO-7a-mediated cytoprotection against oxidative stress. It suggested that its mechanism is independent of the production of L-arginine metabolites with neuroprotective properties by increased AsS activity. On the other hand, the neuroprotective effect of PRO-7a was blocked in the presence of dicyclomine hydrochloride (DCH), an M1 mAChR antagonist. Conclusions: For the first time, this work provides evidence that PRO-7a-induced neuroprotection seems to be mediated through M1 mAChR activation in PC12 cells, which reduces oxidative stress independently of AsS activity and L-arginine bioavailability. (AU)

• FAPESP's process: 23/03608-1 - Bioprospection of neuroprotective peptides from snake venoms in vitro and in vivo experimental models for the study of neurodegenerative diseases
• Grantee: Carlos Alberto da Silva
• Support Opportunities: Regular Research Grants