Formation of excessive fibrous tissue – a build up of connective tissue which leads to tissue hardening – is a contributing factor in up to 40 percent of all deaths in industrialised countries. In spite of this there are currently very few effective treatments available. Medical researchers at FAU have recently discovered a molecular mechanism which could hold the key to new treatments for fibrosis. The results of their research show that transforming growth factor beta (TGF-beta) – an important protein in growth processes – and the nuclear receptor NR4A1 have key functions in normal wound healing and in fibrotic diseases. The researchers’ findings have recently been published in the renowned journal Nature Medicine. (doi: 10.1038/nm.3777)
In fibrotic diseases such as systemic sclerosis excessive activation of connective tissue cells leads to tissue hardening. These diseases can affect any organ system and often lead to disruption of organ function. Connective tissue cells play a key role in normal wound healing and in fibrotic diseases. Researchers suspect that repair processes do not stop properly in fibrotic diseases, meaning that these processes are over-activated which in turn causes build-ups of extracellular connective tissue. However, until now it was unclear why repair processes malfunction in fibrotic diseases.
A team of researchers from the Chair of Internal Medicine 3 (Rheumatology and Immunology) at FAU, led by Prof. Dr. Jörg Distler, have recently discovered a molecular mechanism that is responsible for activating continuous regeneration processes. The researchers examined TGF-beta in experimental studies. In normal wound healing increased quantities of TGF-beta are temporarily produced to stimulate the repair of the tissue damage. Towards the end of the healing process the TGF-beta levels decrease again and the connective tissue cells return to their normal state. ‘We were able to show that in fibrotic diseases TGF-beta stays active and causes continuous stimulation of connective tissue cells, leading to continuous build-up of tissue,’ explains Professor Distler. The nuclear receptor NR4A1 plays a key role in the regulation of TGF-beta activity. In normal wound healing NR4A1 restricts the effects of TGF-beta. In fibrotic diseases this mechanism is prevented due to inactivation of the receptor. This means that TGF-beta can continue working without limitation and the repair process is not stopped.
‘In our experiments we were able to show that NR4A1 can be reactivated pharmacologically. This restricts TGF-beta, prevents over-activation of connective tissue cells and effectively combats fibrosis,’ says Prof. Dr. Jörg Distler. The discovery of this mechanism could lead to the development of innovative new forms of treatment for fibrotic diseases.
Source: Palumbo-Zerr K, et al. Nat Med. 2015 Jan 12. doi: 10.1038/nm.3777.
Prof. Dr. med. Jörg Distler
Phone: +49 9131 8534742