Erratum: Reduction of Abeta amyloid pathology in APPPS1 transgenic mice in the absence of gut microbiota.

This corrects the article DOI: 10.1038/srep41802.

Reduction of Abeta amyloid pathology in APPPS1 transgenic mice in the absence of gut microbiota.

Alzheimer's disease is the most common form of dementia in the western world, however there is no cure available for this devastating neurodegenerative disorder. Despite clinical and experimental evidence implicating the intestinal microbiota in a number of brain disorders, its impact on Alzheimer's disease is not known. To this end we sequenced bacterial 16S rRNA from fecal samples of Aß precursor protein (APP) transgenic mouse model and found a remarkable shift in the gut microbiota as compared to non-transgenic wild-type mice. Subsequently we generated germ-free APP transgenic mice and found a drastic reduction of cerebral Aß amyloid pathology when compared to control mice with intestinal microbiota. Importantly, colonization of germ-free APP transgenic mice with microbiota from conventionally-raised APP transgenic mice increased cerebral Aß pathology, while colonization with microbiota from wild-type mice was less effective in increasing cerebral Aß levels. Our results indicate a microbial involvement in the development of Abeta amyloid pathology, and suggest that microbiota may contribute to the development of neurodegenerative diseases.

Neurodegeneration in models of Gram-positive bacterial infections of the central nervous system.

Gram-positive bacterial infections of the central nervous system, such as meningitis, induce an extensive inflammatory response, which in turn may damage neurons. LTA (lipoteichoic acid) is a component of the Gram-positive bacterial cell wall that induces glial inflammatory activation in vitro and in vivo. It does so by binding to Toll-like receptor-2 on microglia and astrocytes, rapidly activating ERK1/2 (extracellular-signal-regulated kinase 1/2) and p38 MAPKs (mitogen-activated protein kinases), causing NF-kappaB (nuclear factor kappaB) activation and leading to the production of pro-inflammatory cytokines and expression of inducible nitric oxide synthase (in synergy with muramyl dipeptide). LTA-activated microglia kill co-cultured neurons apparently via nitric oxide, superoxide and peroxynitrite, which may induce apoptosis of neurons that are then phagocytosed by microglia.