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).
Asma Nusrat, MD
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. Read more
In the September issue of the Journal of the American Academy of Dermatology, Jack Arbiser and colleagues describe the use of gentian violet to provide some relief to a patient who came to the emergency room with a painful skin irritation. Arbiser is a professor of dermatology at Emory University School of Medicine.
A coal-tar dye which is inexpensive and availableÂ over the counter, gentian violet was first synthesized in the 19th century. It has been used as a component of paper ink, a histological stain, and an antibiotic or antifungal agent, especially before the arrival of penicillin.
“Clinicians should not forget about gentian violet for immediate pain relief and antibiotic coverage,” the authors conclude in their case report.
Biopsy of the patient's irritated skin shows that the gene angiopoetin-2 (dark brown) is turned on
In addition to its antibiotic properties, Arbiser reports that gentian violet has antiinflammatory effects, possibly because of its inhibition of the enzyme NADPH oxidase and the gene angiopoetin-2.
Posted on September 9, 2010
Why arenâ€™t antioxidants magic cure-alls?
Itâ€™s not a silly question, when one sees how oxidative stress and reactive oxygen species have been implicated in so many diseases, ranging from hypertension and atherosclerosis to neurodegenerative disorders. Yet large-scale clinical trials supplementing participantsâ€™ diets with antioxidants have showed little benefit.
Emory University School of Medicine scientists have arrived at an essential insight: the cell isnâ€™t a tiny bucket with all the constituent chemicals sloshing around. To modulate reactive oxygen species effectively, an antioxidant needs to be targeted to the right place in the cell.
Sergei Dikalov and colleagues in the Division of Cardiology have a paper in the July 9 issue ofÂ Circulation Research, describing how targeting antioxidant molecules to mitochondria dramatically increases their effectiveness in tamping down hypertension.
Mitochondria are usually described as miniature power plants, but in the cells that line blood vessels, they have the potential to act as amplifiers. The authors describe a â€œvicious cycleâ€ of feedback between the cellular enzyme NADPH oxidase, which produces the reactive form of oxygen called superoxide, and the mitochondria, which can also make superoxide as a byproduct of their energy-producing function.
Kathy Griendling, PhD (in green), surrounded by members of her lab
On June 15, 2010, vascular biologist Kathy Griendling delivered the 2010 Dean’s Distinguished Faculty lecture at Emory University School of Medicine.
Some of Griendling’s publications have been cited thousands of times by fellow scientists around the world, making her the lead member of a small group of researchers at Emory called theÂ “Millipub Club.”
With her five children and one grandson watching in the back row, Griendling explained how she and her colleagues, over the course of more than two decades at Emory, have gradually revealed the functions of a family of enzymes called NADPH oxidases in vascular smooth muscle cells. Read more
Posted on June 28, 2010