Smad7, A Type Of Protein In The Gut Plays Role In The Development Of Multiple Sclerosis
Source: Thailand Medical News Dec 05, 2019 4 years, 5 months, 3 days, 10 hours, 32 minutes ago
The human
gut has long been suspected to play a role in autoimmune disease. A research team has now identified evidence of a potential mechanism.
Which factors in patients with
multiple sclerosis (MS) act as a trigger for the immune system to attack the brain and spinal cord is still not understood or known. A potential factor is described by a research team in the journal
Proceedings of the National Academy of Sciences,
PNAS. The medical researchers used an animal model to show that the protein
Smad7 mobilizes immune cells in the intestines which, in turn, trigger inflammation in the central nervous system. Analyses of intestinal tissue samples taken from
Multiple Sclerosis patients confirmed the results, which were published online on 4 December 2019.
The research study was conducted at the Department of Neurology and the Centre of Neuroimmunology at St. Josef-Hospital, university hospital of Ruhr-Universität Bochum. The Bochum-based group with biologist Dr. Steffen Haupeltshofer and neurologists Professor Simon Faissner and Professor Ingo Kleiter, formerly at the Bochum university hospital, currently at Marianne-Strauß-Klinik in Berg, collaborated with other colleagues from Bochum, Bremen, Mainz, Düsseldorf, Jülich and Rome.
The medical researchers initially analyzed the signal protein
Smad7 in intestinal immune cells in mice, or more precisely: in T-cells. The researchers compared genetically modified mice with a normal and those with a particularly high quantity of
Smad7 in T-cells as well as mice without any
Smad7 in T-cells. They monitored if the animals developed opticospinal encephalomyelitis, a disease that mimics
Multiple Sclerosis in humans.
The most strongest clinical
Multiple Sclerosis-like symptoms occurred in animals with an increased
Smad7 level in T-cells. In their intestines, T-cells were more frequently activated, which then migrated into the central nervous system where they triggered inflammation. Moreover, the ratio of protective regulatory T-cells to pathogenic autoreactive T-cells had changed. In mice that didn't have any
Smad7 protein, no clinical signs of a
Multiple Sclerosis-like disease occurred.
Consequently, the researchers analysed tissue samples taken from the intestines of 27
Multiple Sclerosis patients and compared them with samples taken from 27 healthy individuals. In the patients, they identified changes similar to those in the animal model: the signal protein
Smad7 occurred more frequently in intestinal mucosa samples of
Multiple Sclerosis patients than in those of healthy individuals; in addition, an abnormal ratio of regulatory to pathogenic mechanisms was identified in intestinal mucosa samples in patients.
Dr Simon Faissner todl
Thailand Medical
>News, "For other autoimmune diseases such as Crohn's and other inflammatory bowel diseases, researchers are already aware that
Smad7 offers a promising therapeutic target; our results suggest that the same is true for
multiple sclerosis," says Ingo Kleiter. "Researchers are increasingly exploring intestinal involvement in the development and progression of
Multiple Sclerosis."
Reference : Steffen Haupeltshofer et al. Smad7 in intestinal CD4+ T cells determines autoimmunity in a spontaneous model of multiple sclerosis, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1905955116
