Absence of receptor for advanced glycation end product (RAGE) reduces inflammation and extends survival in the hSOD1G93A mouse model of amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis (ALS) is a fatal and rapidly progressing motor neuron degenerative disease that is without effective treatment. The receptor for advanced glycation end products (RAGE) is a major component of the innate immune system that has been implicated in ALS pathogenesis. However, the contribution of RAGE signaling to the neuroinflammation that underlies ALS neurodegeneration remains unknown. The present study therefore generated SOD1G93A mice lacking RAGE, and compared them to SOD1G93A transgenic ALS mice in respect to disease progression (i.e. body weight, survival and muscle strength), neuroinflammation and denervation markers in the spinal cord and tibialis anterior muscle. We found that complete absence of RAGE signaling exerted a protective effect on SOD1G93A pathology, slowing disease progression and significantly extending survival by [~]3 weeks, and improving motor function (rotarod and grip strength). This was associated with reduced microgliosis, cytokines, innate immune factors (complement, TLRs, inflammasomes), and oxidative stress in the spinal cord, and a reduction of denervation markers in the tibialis anterior muscle. We also documented that RAGE mRNA expression was significantly increased in the spinal cord and muscles of preclinical SOD1 and TDP43 models of ALS, supporting a widespread involvement for RAGE in ALS pathology. In summary, our results indicate that RAGE signalling drives neuroinflammation and contributes to neurodegeneration in ALS, and highlights RAGE as a potential immune therapeutic target for ALS.