Alpha-1 Antitrypsin Reduces Disease Progression in a Mouse Model of Charcot-Marie-Tooth Type 1A: A Role for Decreased Inflammation and ADAM-17 Inhibition.

Charcot-Marie-Tooth disease type 1 (CMT1A) is a hereditary peripheral neuropathy for which there is no available therapy. Alpha-1 antitrypsin (AAT) is an abundant serine protease inhibitor with anti-inflammatory and immunomodulating properties. Here, we tested whether treatment with human AAT (hAAT) would have a therapeutic effect on CMT1A in a PMP22 transgenic mouse model. Our results show that hAAT significantly improved compound muscle action potential and histopathological features and decreased circulating IL-6 in CMT1A mice. We also investigated some of the possible underlying mechanisms in vitro. We confirmed that hAAT inhibits ADAM-17, a protease that has been implicated in blocking myelination. Furthermore, both hAAT and recombinant human AAT (rhAAT) were able to attenuate the activation of a macrophage/microglia cell line, markedly decreasing the activation of the MHC class II promoter and the expression of pro-inflammatory genes such as IL-1β and the endoplasmic reticulum (ER) stress marker ATF3 . Taken together, our results demonstrate for the first time that hAAT is able to reduce the progression of CMT1A, possibly by dampening inflammation and by regulating ADAM-17. Given the already well-established safety profile of hAAT, specifically in AAT deficiency disease (AATD), we suggest that the findings of our study should be promptly investigated in CMT1A patients.