AÂ Emory News item on a helpful part of the microbiome focuses on how the same type of bacteria â€“ lactobacilli â€“ activates the same ancient signaling pathway in intestinal cells in both insects and mammals.Â It continues a line of research from Rheinallt Jones and Andrew Neish on how beneficial bacteria stimulate wound healing by activating ROS (reactive oxygen species).
A idea behind this research is: if we know what parts of the bacteria stimulate healing, perhaps doctors can deliverÂ that material, or something very close, to patients directly to treat intestinal diseases such as Crohn’s or ulcerative colitis.
This ideaÂ has advanced experimentally, as demonstrated byÂ twoÂ papers from Jones and Neishâ€™s frequent collaborator, Asma Nusrat, who recently moved from Emory to the University of Michigan. This team had shown that a protein produced by human intestinal cells called annexin A1 activates ROS, acting through the same N-formyl peptide receptors that bacteria do.
Nusrat told me Friday her team began investigatingÂ annexins a decade ago at Emory, and it was fortuitous that Neish was working on beneficial bacteria right down the hall, since it is now apparent that annexin A1 and the bacteria areÂ activating the same molecular signals.Â (Did you know there is an entire conference devoted to annexins? I didn’t until a few days ago.)
In aÂ secondÂ Journal of Clinical Investigation paper published this February, NusratÂ and herÂ colleagues show that intestinal cells release vesicles containing annexin A1 following injury. The wound closure-promoting effects of these vesicles can be mimicked with nanoparticles containing annexin A1. The nanoparticles incorporate a form of collagen, which targets them to injured intestinal tissue.
The first author of bothÂ JCI papersÂ isÂ postdoc Giovanna Leoni, now in Munich, Germany. If you’re looking forÂ more great imagesÂ like the one of Drosophila intestine with bacteria, JCI editors designated thisÂ photoÂ from Leoni’sÂ 2015 paper as a “Scientific Show-Stopper”.
Nusrat has also begunÂ collaborating with Georgia Tech’s Andres Garcia to deliver intestinal stem cells in hydrogels.