Biogenic silver nanoparticles (AgNp-Bio) reduce Toxoplasma gondii infection and proliferation in HeLa cells, and induce autophagy and death of tachyzoites by apoptosis-like mechanism

Acta Trop. 2021 Jul 28:106070. doi: 10.1016/j.actatropica.2021.106070. Online ahead of print.ABSTRACTToxoplasma gondii is a protozoan parasite that can cause severe and debilitating diseases, especially in immunocompromised individuals. The available treatment is based on drugs that have low efficacy, high toxicity, several adverse effects, and need long periods of treatment. Thus, the search for therapeutic alternatives is urgently needed. Biogenic silver nanoparticles (AgNp-Bio) have been associated with several biological effects, as antiproliferative, pro-apoptotic, antioxidant, antiviral, antifungal, and antiprotozoal activity. Thus, the objective was evaluating AgNp-Bio effect on HeLa cells infected with T. gondii (RH strain). First, nontoxic AgNp-Bio concentrations for HeLa cells (1.5 - 6 µM) were determined, which were tested on cells infected with T. gondii. A significant reduction in infection, proliferation, and intracellular parasitic load was observed, also an increase in ROS and IL-6. Additionally, the evaluation of the action mechanisms of the parasite showed that AgNp-Bio acts directly on tachyzoites, inducing depolarization of the mitochondrial membrane, ROS increase, and lipid bodies accumulation, as well as triggering an autophagic process, causing damage to the parasite membrane, and phosphatidylserine exposure. Based on this, it was inferred that AgNp-Bio affects T. gondii by inducing immunomodulation and microbicidal molecules production produced by inf...

Source: Acta Tropica - July 31, 2021 Category: Infectious Diseases Authors: Raquel Arruda da Silva Sanfelice Bruna Taciane da Silva Bortoleti Fernanda Tomiotto-Pellissier Taylon Felipe Silva Larissa Rodrigues Bosqui Gerson Nakazato Pablo Menegon Castilho Luiz Daniel de Barros Jo ão Luis Garcia Danielle Lazarin-Bid óia Ivete Con Source Type: research