The Controversial Role of Human Gut Lachnospiraceae

Abstract

The complex polymicrobial composition of human gut microbiota plays a key role in health and disease. Lachnospiraceae belong to the core of gut microbiota, colonizing the intestinal lumen from birth and increasing, in terms of species richness and their relative abundances during the host's life. Although, members of Lachnospiraceae are among the main producers of short-chain fatty acids, different taxa of Lachnospiraceae are also associated with different intra- and extraintestinal diseases. Their impact on the host physiology is often inconsistent across different studies. Here, we discuss changes in Lachnospiraceae abundances according to health and disease. With the aim of harnessing Lachnospiraceae to promote human health, we also analyze how nutrients from the host diet can influence their growth and how their metabolites can, in turn, influence host physiology.

Keywords: Lachnospiraceae; disease; gut microbial metabolites; gut microbial pathways; gut microbiota; health.

Figure 1

Phylogeny of taxa belonging to the Lachnospiraceae family. Sequences have been retrieved from the RefSeq Targeted Loci Project included in the National Center for Biotechnology Information (NCBI) database using the following combined search: txid186803[ORGN] AND (33175[Bioproject] OR 33317[Bioproject] of bacterial 16S ribosomal RNA. The nucleotide sequences have been multiply aligned using MAFFT tool version 7.427 (https://mafft.cbrc.jp/alignment/software/) and the approximately-maximum-likelihood phylogenetic tree has been inferred from the nucleotide alignments by using the general time-reversible model (GTR).

Figure 2

Reconstruction of the main microbial pathways associated to Lachnospiraceae in human gut. The panel in blue shows a schematic representation of the metabolic pathways involved in the biosynthesis of acetate and butyrate, as well as the main pathways of carbohydrate degradation (yellow). The green panel shows a schematic representation of metabolic pathways of aromatic amino acids involved in the biosynthesis of indole-propionic acid, indole, phenol, and p-cresol.