The Microbiota-Gut-Brain Axis

Abstract

The importance of the gut-brain axis in maintaining homeostasis has long been appreciated. However, the past 15 yr have seen the emergence of the microbiota (the trillions of microorganisms within and on our bodies) as one of the key regulators of gut-brain function and has led to the appreciation of the importance of a distinct microbiota-gut-brain axis. This axis is gaining ever more traction in fields investigating the biological and physiological basis of psychiatric, neurodevelopmental, age-related, and neurodegenerative disorders. The microbiota and the brain communicate with each other via various routes including the immune system, tryptophan metabolism, the vagus nerve and the enteric nervous system, involving microbial metabolites such as short-chain fatty acids, branched chain amino acids, and peptidoglycans. Many factors can influence microbiota composition in early life, including infection, mode of birth delivery, use of antibiotic medications, the nature of nutritional provision, environmental stressors, and host genetics. At the other extreme of life, microbial diversity diminishes with aging. Stress, in particular, can significantly impact the microbiota-gut-brain axis at all stages of life. Much recent work has implicated the gut microbiota in many conditions including autism, anxiety, obesity, schizophrenia, Parkinson’s disease, and Alzheimer’s disease. Animal models have been paramount in linking the regulation of fundamental neural processes, such as neurogenesis and myelination, to microbiome activation of microglia. Moreover, translational human studies are ongoing and will greatly enhance the field. Future studies will focus on understanding the mechanisms underlying the microbiota-gut-brain axis and attempt to elucidate microbial-based intervention and therapeutic strategies for neuropsychiatric disorders.

Faecal microbiota transplant from aged donor mice affects spatial learning and memory via modulating hippocampal synaptic plasticity- and neurotransmission-related proteins in young recipients

“…In particular, a deficit of hippocampal-dependent functions, including spatial learning and memory is a distinctive trait of ageing [17]. Although the role of the gastrointestinal tract and gut microbiome on the development and function of the CNS has become evident in the past few years [2][3][4][5][6], the extent of the impact of the age-associated shits of the gut microbiota on specific functions of the CNS remained to be determined. Here we report that FMT from aged donors affects memory and spatial learning in transplanted adult mice, a phenomenon led through a differential expression of proteins involved in maintenance of synaptic plasticity and neurotransmission in the hippocampus area.…”

“…Ageing is an inevitable process that starts immediately after birth and ultimately leads to the loss of functional capacity in several body systems, including the cardiovascular, skeletomuscular, osteoarticular and neuro-immune-endocrine, and is often associated with a decline in psychological wellbeing and cognitive function. In the past few years it has been brought to the surface that events taking place in the gut play an important role in the ageing process [1] and recently, the existence of bidirectional communication between the gut and the brain -the gut-brain axis -has emerged as an important player in shaping aspects of behaviour and cognitive function [2]. In particular, the gut microbiome has been reported to play an important role within this scenario.…”

Annual Research Review: Critical windows – the microbiota–gut–brain axis in neurocognitive development

“…The past decade has seen this idea of ‘something more’ expand to the trillions of bacteria within the gut, the microbiota (Cryan et al, ; Rhee et al, ). Indeed, there has been an explosion of research investigating the microbiota and its contribution to all aspects of human health and disease, including psychological well‐being and neurodevelopment.…”

High-Throughput Stool Metaproteomics: Method and Application to Human Specimens

“…The gut microbiome is characterized by numerous complex interactions influencing human health and disease, and has been associated with disorders ranging from inflammatory bowel disease to autism 1,2 . Stool is a biologically rich biomaterial, containing host, microbe, and dietary proteins, among a rich array of biomolecules.…”