ALS-related p97 R155H mutation disrupts lysophagy in iPSC-derived motor neurons
(2024) Stem Cell Reports, .
Klickstein, J.A.a , Johnson, M.A.a , Antonoudiou, P.b , Maguire, J.b , Paulo, J.A.c , Gygi, S.P.c , Weihl, C.d , Raman, M.a
a Department of Developmental Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, United States
b Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
c Department of Cell Biology, Harvard Medical School, Boston, MA, United States
d Department of Neurology, Washington University at St. Louis, St. Louis, MO, United States
Abstract
Mutations in the AAA+ ATPase p97 cause multisystem proteinopathy 1, which includes amyotrophic lateral sclerosis; however, the pathogenic mechanisms that contribute to motor neuron loss remain obscure. Here, we use two induced pluripotent stem cell models differentiated into spinal motor neurons to investigate how p97 mutations perturb the motor neuron proteome. Using quantitative proteomics, we find that motor neurons harboring the p97 R155H mutation have deficits in the selective autophagy of lysosomes (lysophagy). p97 R155H motor neurons are unable to clear damaged lysosomes and have reduced viability. Lysosomes in mutant motor neurons have increased pH compared with wild-type cells. The clearance of damaged lysosomes involves UBXD1-p97 interaction, which is disrupted in mutant motor neurons. Finally, inhibition of the ATPase activity of p97 using the inhibitor CB-5083 rescues lysophagy defects in mutant motor neurons. These results add to the evidence that endo-lysosomal dysfunction is a key aspect of disease pathogenesis in p97-related disorders. © 2024 The Author(s)
Author Keywords
ALS; autophagy; galectin; lysophagy; lysosome; mitochondria; p97; proteomics
Funding details
National Institutes of HealthNIH1070479, GM127557, NS123631
Muscular Dystrophy AssociationMDAAA026256, AG031867, AR073317, GM132129, GM133314, GM67945, MH122379, MH128235, NS102937, NS105628
Document Type: Article
Publication Stage: Article in Press
Source: Scopus
Comparison of Behavioral Effects of GABAergic Low- and High-Efficacy Neuroactive Steroids in the Zebrafish Larvae Assay
(2023) ACS Chemical Neuroscience, .
Germann, A.L., Xu, Y., Covey, D.F., Evers, A.S., Akk, G.
Department of Anesthesiology, Developmental of Biology, Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St Louis, MO 63110, United States
Abstract
Activation of the GABAA receptor is associated with numerous behavioral end points ranging from anxiolysis to deep anesthesia. The specific behavioral effect of a GABAergic compound is considered to correlate with the degree of its functional effect on the receptor. Here, we tested the hypothesis that a low-efficacy allosteric potentiator of the GABAA receptor may act, due to a ceiling effect, as a sedative with reduced and limited action. We synthesized a derivative, named (3α,5β)-20-methyl-pregnane-3,20-diol (KK-235), of the GABAergic neurosteroid 5β-pregnane-3α,20α-diol. Using electrophysiology, we showed that KK-235 is a low-efficacy potentiator of the synaptic-type α1β2γ2L GABAA receptor. In the zebrafish larvae behavioral assay, KK-235 was found to only partially block the inverted photomotor response (PMR) and to weakly reduce swimming behavior, whereas the high-efficacy GABAergic steroid (3α,5α,17β)-3-hydroxyandrostane-17-carbonitrile (ACN) fully blocked PMR and spontaneous swimming. Coapplication of KK-235 reduced the potentiating effect of ACN in an electrophysiological assay and dampened its sedative effect in behavioral experiments. We propose that low-efficacy GABAergic potentiators may be useful as sedatives with limited action. © 2024 American Chemical Society.
Author Keywords
behavior; function; GABAA receptor; neuroactive steroids; potentiation; sedatives
Funding details
P50MH122379
National Institute of General Medical SciencesNIGMSR35GM140947, R35GM149287
Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine in St. Louis
Document Type: Article
Publication Stage: Article in Press
Source: Scopus