Inhibiting neuronal degeneration and why muscles fall asleep
Also this week MedZine brings you the latest medical news on various medical specialisms. In this editorial two striking studies in the field of neurology are highlighted. The first identifies an inhibitor that slows neuronal degeneration and shows potential as a therapy against Alzheimer’s disease. The second describes how muscles accidentally fall asleep while someone is awake.
Researcher identify a compound that may be a new therapeutic target for neurodegenerative diseases
Conditions such as Alzheimer’s and Parkinson’s disease are caused by the degeneration of neurons. In a publication in Science Translational Medicine, Ortori and colleagues show that an inhibitor of protein kinase RNA–like endoplasmic reticulum kinase (PERK) has neuroprotective effects. PERK is a key mediator in the unfolded protein response (UPR) pathway, which is overactive when misfolded prion proteins are present. In mice, oral treatment with the Perk inhibitor prevented UPR-mediated translational repression and abrogated development of clinical prion disease. Neuroprotection was observed throughout the mouse brain. The inhibitor was effective in a preclinical stage as well as in a later stage when behavioral symptoms have emerged. The researchers state that these data suggest that PERK, and other members of this pathway, may be new therapeutic targets for developing drugs against prion disease or other neurodegenerative diseases.
Mechanism behind cataplexy
Cataplexy is a rare condition were the body's muscles ‘fall asleep’ and become involuntarily paralyzed. It is a symptom of the sleep disorder narcolepsy and is very incapacitating. The individual is awake but can’t move. In a publication in Current Biology, Burgess and Peever describe the mechanism behind this condition. Cataplexy is caused by a loss of hypocretin cells and the researchers used hypocretin knockout mice to identify the neurochemical cause of cataplexy. They show that the noradrenergic system acts to synchronize motor and arousal systems. Excitatory noradrenergic drive maintains postural muscle tone during wakefulness by activating α1-receptors on skeletal motoneurons. The researchers show that loss of this noradrenergic drive causes muscle tone to fall and restoring this drive rescues cataplexy.
Sources: Eurekalert, Science Translational Medicine, and Current Biology