Mutations in GFAP Disrupt the Distribution and Function of Organelles in Human Astrocytes
Jeffrey R. Jones,
Linghai Kong,
Michael G. Hanna, IV,
Brianna Hoffman,
Robert Krencik,
Robert Bradley,
Tracy Hagemann,
Jeea Choi,
Matthew Doers,
Marina Dubovis,
Mohammad Amin Sherafat,
Anita Bhattacharyya,
Christina Kendziorski,
Anjon Audhya,
Albee Messing,
Su-Chun Zhang
Affiliations
Jeffrey R. Jones
Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
Linghai Kong
Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
Michael G. Hanna, IV
Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
Brianna Hoffman
Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
Robert Krencik
Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
Robert Bradley
Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
Tracy Hagemann
Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
Jeea Choi
Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI 53706, USA
Matthew Doers
Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
Marina Dubovis
Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
Mohammad Amin Sherafat
Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
Anita Bhattacharyya
Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
Christina Kendziorski
Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI 53706, USA
Anjon Audhya
Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
Albee Messing
Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA
Su-Chun Zhang
Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neurology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA; Program in Neuroscience & Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore; Corresponding author
Summary: How mutations in glial fibrillary acidic protein (GFAP) cause Alexander disease (AxD) remains elusive. We generated iPSCs from two AxD patients and corrected the GFAP mutations to examine the effects of mutant GFAP on human astrocytes. AxD astrocytes displayed GFAP aggregates, recapitulating the pathological hallmark of AxD. RNA sequencing implicated the endoplasmic reticulum, vesicle regulation, and cellular metabolism. Corroborating this analysis, we observed enlarged and heterogeneous morphology coupled with perinuclear localization of endoplasmic reticulum and lysosomes in AxD astrocytes. Functionally, AxD astrocytes showed impaired extracellular ATP release, which is responsible for attenuated calcium wave propagation. These results reveal that AxD-causing mutations in GFAP disrupt intracellular vesicle regulation and impair astrocyte secretion, resulting in astrocyte dysfunction and AxD pathogenesis. : Jones et al. study the structure function relationship of GFAP on astrocytes using Alexander disease patient-derived induced pluripotent stem cells. Mutations in GFAP result in mislocalization of organelles and functional consequences such as reduced ATP release and attenuated calcium wave propagation. Genetic correction of mutant GFAP rescues these defects. Keywords: Alexander disease, iPSC, CRISPR, endoplasmic reticulum, lysosome
