UNICAMP Researchers Uncover Dual-Function Intestinal Cells Regulated by Gut Microbiota

Researchers from the State University of Campinas (UNICAMP) in Brazil have identified a specific cell type in the large intestine that performs both mucus secretion and nutrient absorption, a function not previously attributed to it. Published in Gut Microbes, the study details how the abundance of these dual-function cells is regulated by gut microbiota and its metabolic compounds, such as butyrate.

This discovery contributes to understanding intestinal plasticity, particularly in conditions like inflammatory bowel disease and age-related changes to the intestinal wall.

Study Overview

A research team led by scientists from the State University of Campinas (UNICAMP) in Brazil has investigated the interaction between gut microbiota and intestinal cells. Their study, published in Gut Microbes, detailed how the gut microbiota and its produced compounds, including butyrate, influence the function of cells lining the large intestine. This intestinal layer is known for producing mucus, which contributes to its barrier function by preventing bacterial entry into the body.

Key Findings

The research identified a cell type within the intestinal epithelium previously classified exclusively as mucus-secreting that also performs nutrient absorption. These dual-function cells were found to express genes for both mucus secretion and absorption, indicating an adaptive capability of the intestinal epithelium.

The study determined that the presence of these cells is regulated by signals from the gut microbiota. Their numbers increase when the gut microbiota is reduced. Butyrate, a compound derived from dietary fiber fermentation, along with its receptor GPR109A, also regulates the abundance of this cell type. Higher butyrate production correlates with fewer of these cells.

Vinicius Dias Nirello, the study's first author, explained that a reduction in microbiota causes the large intestine, which typically prioritizes mucus production, to exhibit characteristics of nutrient absorption usually observed in the small intestine. This change, potentially an adaptive response to decreased bacteria, may be linked to the expansion of these dual-function cells.

Professor Marco Vinolo added that while butyrate reduces these cells, conditions of dysbiosis—defined as a loss of bacteria due to factors such as antibiotic use or aging—lead to their expansion, a response hypothesized to reinforce the intestinal barrier.

Furthermore, the specific cell population was observed to be more prevalent in the large intestines of older individuals, a finding supported by analysis of human biopsies and observations in mice with microbiota from older human donors.

Implications

This research provides a foundation for understanding the role of microbiota and its metabolites in conditions such as inflammatory bowel disease (IBD), potentially aiding in the development of treatments. The findings also illustrate how the integrity of the intestinal wall can change, particularly in older individuals. The study highlights a previously unrecorded level of plasticity within the intestinal epithelium, governed by microbial triggers.

Methodology

To conduct the study, researchers utilized several experimental approaches. They treated mice with antibiotics to significantly reduce their gut microbiota, comparing them to a control group with intact microbiota.

Germ-free animals were also employed, divided into subgroups that received bacteria transplanted from either young (18-35 years old) or older (over 65 years old) human donors to investigate age-related microbiota effects.

In addition to mouse models, biopsies from the large intestines of young and older adult humans were analyzed to assess the impact of aging on intestinal epithelial cells. Single-cell transcriptomics technology was applied to mouse samples, allowing for detailed examination of individual cell characteristics, including enterocytes (involved in nutrient absorption) and goblet cells (involved in mucus secretion).

Future Research

Researchers plan further experiments, such as deleting secretory or absorptive genes in these dual-function cells, to clarify their precise role. This future work aims to advance understanding and treatment of intestinal diseases.