Methylmercury Interactions With Gut Microbiota and Potential Modulation of Neurogenic Niches in the Brain

Front Neurosci. 2020 Nov 3:14:576543. doi: 10.3389/fnins.2020.576543. eCollection 2020.

Methylmercury Interactions With Gut Microbiota and Potential Modulation of Neurogenic Niches in the Brain

Daniel V Pinto  1 , Ramon S Raposo  2 , Gabriella A Matos  1 , Jacqueline I Alvarez-Leite  3 , João O Malva  4 , Reinaldo B Oriá  1

1 Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology, School of Medicine, Institute of Biomedicine, Federal University of Ceara, Fortaleza, Brazil.

2 Experimental Biology Core, University of Fortaleza, Fortaleza, Brazil.

3 Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil.

4 Center for Innovative Biomedicine and Biotechnology (CIBB), Faculty of Medicine, Institute of Pharmacology and Experimental Therapeutics, Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, Coimbra, Portugal.

Conclusion and Perspectives

This opinion paper discussed the role of the intestinal microbiota on MeHg neurointoxication with potential consequences for the hippocampal neurogenic niche. Novel breakthrough findings are much supportive of human neurogenesis even in elderly (Boldrini et al., 2018), which was not universally accepted (Sorrells et al., 2018). Activity of NSCs and renewal of hippocampal neurons even in adulthood may be a protective/preventive factor against neurodegenerative diseases. New available neuroimaging tools to study the human brain neurogenesis may shed light to MeHg deleteriously effects on dynamic processes occurring in the hippocampal neurogenic niche during lifespan.

Accumulating evidence implies the gut-brain axis as a pathway for MeHg harmful neurotoxic effects and a potential factor for later neurodegenerative disorders. The MeHg may induce a hormesis-related neuronal toxicity. Hormesis is an important redox dependent aging-associated neurodegenerative/ neuroprotective issue (Calabrese et al., 2010). The use of antioxidants, such as plant polyphenols (Calabrese et al., 2010; Leri et al., 2020) and protective nutrients (Oria et al., 2020) may be beneficial in reducing the MeHg-driven neuroinflammatory state and associated cell death with the interplay of the intestinal microbiota. Further research is warranted to elucidate the fine molecular mechanisms and NSC biomarkers during lifelong hippocampal neurogenesis and how they are affected by MeHg. Such findings may contribute to health policies in highly endemic MeHg intoxication and poor sanitation settings.