Optineurin deficiency induces patchy hair loss but it is not sufficient to cause amyotrophic lateral sclerosis in mice

Abstract

Genetic alterations and environmental factors contribute towards pathogenesis of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease. Various types of mutations in the autophagy receptor protein optineurin (coded by OPTN gene) including deletions are causatively associated with ALS. To explore the role of OPTN in ALS pathogenesis, we used Optn knockout mice to study the features of ALS. The Optn-deficient mice did not show kyphosis, loss of body weight, weakening of front paw-grip strength or limb muscle strength. However, several Optn-deficient mice showed patchy loss of hair, which increased with age. Our results suggest that optineurin deficiency alone is not sufficient to induce ALS-like symptoms in mice. We suggest that optineurin deficiency may require cooperation with other genetic or environmental factors to cause ALS. Since endoplasmic reticulum (ER) stress plays an important role in ALS pathogenesis, and Optn modulates ER stress response signaling, Optn deficiency may contribute to ALS pathogenesis partly by potentiating ER stress response signaling.