Heavy Metal Interactions with Neuroglia and Gut Microbiota: Implications for Huntington's Disease

Abstract

Huntington's disease (HD) is a rare but progressive and devastating neurodegenerative disease characterized by involuntary movements, cognitive decline, executive dysfunction, and neuropsychiatric conditions such as anxiety and depression. It follows an autosomal dominant inheritance pattern. Thus, a child who has a parent with the mutated huntingtin (mHTT) gene has a 50% chance of developing the disease. Since the HTT protein is involved in many critical cellular processes, including neurogenesis, brain development, energy metabolism, transcriptional regulation, synaptic activity, vesicle trafficking, cell signaling, and autophagy, its aberrant aggregates lead to the disruption of numerous cellular pathways and neurodegeneration. Essential heavy metals are vital at low concentrations; however, at higher concentrations, they can exacerbate HD by disrupting glial-neuronal communication and/or causing dysbiosis (disturbance in the gut microbiota, GM), both of which can lead to neuroinflammation and further neurodegeneration. Here, we discuss in detail the interactions of iron, manganese, and copper with glial-neuron communication and GM and indicate how this knowledge may pave the way for the development of a new generation of disease-modifying therapies in HD.

Keywords: Huntington’s disease; copper; glial cells; gut microbiota; gut–brain axis; heavy metals; iron; manganese; neuroinflammation.

Figure 1

Schematic diagram depicting how heavy metals, via their interactions with the neuroglia and gut microbiota, may contribute to Huntington’s disease (HD) pathology. A detailed understanding of this interaction can pave the way for novel therapeutic interventions in this rare but devastating neurological disease.