A nadA Mutation Confers Nicotinic Acid Auxotrophy in Pro-carcinogenic Intestinal Escherichia coli NC101

A nadA Mutation Confers Nicotinic Acid Auxotrophy in Pro-carcinogenic Intestinal Escherichia coli NC101

Blog Article

Motor Reversing Module Inflammatory bowel diseases (IBDs) and inflammation-associated colorectal cancer (CRC) are linked to blooms of adherent-invasive Escherichia coli (AIEC) in the intestinal microbiota.AIEC are functionally defined by their ability to adhere/invade epithelial cells and survive/replicate within macrophages.Changes in micronutrient availability can alter AIEC physiology and interactions with host cells.Thus, culturing AIEC for mechanistic investigations often involves precise nutrient formulation.We observed that the pro-inflammatory and pro-carcinogenic AIEC strain NC101 failed to grow in minimal media (MM).

We hypothesized that NC101 was unable to synthesize a vital micronutrient normally found in the host gut.Through nutrient supplementation studies, we identified that NC101 is a nicotinic acid (NA) auxotroph.NA auxotrophy was not observed in the other non-toxigenic E.coli or AIEC strains we tested.Sequencing revealed NC101 has a missense mutation in nadA, a gene encoding quinolinate synthase A that is important for de novo nicotinamide adenine dinucleotide (NAD) biosynthesis.

Correcting the identified nadA point mutation Metal Table Lamp (1/CN) restored NC101 prototrophy without impacting AIEC function, including motility and AIEC-defining survival in macrophages.Our findings, along with the generation of a prototrophic NC101 strain, will greatly enhance the ability to perform in vitro functional studies that are needed for mechanistic investigations on the role of intestinal E.coli in digestive disease.