Fat takes over bone marrow niches of important stem and immune cells

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FAU researchers discover link between obesity, immune deficiency and impaired blood formation

Obesity, a widespread disease, affects the body in various different ways. Those affected have an increased risk of sustaining vessel damage or developing diabetes and joint diseases. Little research has so far been conducted regarding the direct impact of this metabolic disorder on bone marrow and on blood formation. Researchers at the new Collaborative Research Centre 1181 at FAU have now discovered that obesity severely impairs blood formation and weakens the immune system.

Stem and immune cells lose their home

Blood formation mainly takes place in the bone marrow where, in specific niches, hematopoietic stem cells develop into blood cells, red and white blood cells and blood platelets. Furthermore, there are specific bone marrow niches where immune cells can mature and train their defences. A pathological increase in body fat also causes a strong increase in bone marrow fat which takes over the niches for stem and immune cells. Bone marrow function is impaired by these alterations and the chances of new bone marrow being produced after transplantation are reduced.

It all starts in the intestine

The team of researchers led by Prof. Dr. Aline Bozec (Chair of Internal Medicine III) and Dr. Stefan Wirtz (Chair of Internal Medicine I) investigated in experiments how high-fat diet specifically modulates the composition of intestinal bacteria. In complex microbiological and genetic examinations of the bowel Bozec and Wirtz were able to show that the metabolic molecular switch PPAR-γ, which is also involved in bone formation, is activated by these modulations. This changes the composition of the bone marrow cavity considerably. Fat tissue in the bone marrow increases and takes over the stem and immune cell niches. The researchers were able to show for the first time a link between unhealthy high-fat diet and damage to the immune system. These findings could be significant for many patients suffering from obesity or diabetes.

The collaborative Research Centre 1181 was funded by the German Research Foundation (DFG), the Federal Ministry of Education and Research (BMBF) and FAU. Prof. Bozec received an appointment as an assistant professor in Erlangen in the context of the Emmy Noether Programme, which was set up to bring excellent international researchers to Germany. The French scientist, who studied in Lyon, had already worked at two renowned European research institutions in Vienna and Madrid before she came to Erlangen.

Further information:

Prof. Dr. Georg Schett
Phone: +49 9131 8539133