title: Traumatically injured astrocytes release a proteomic signature modulated by STAT3-dependent cell survival.
abstract: Molecular markers associated with CNS injury are of diagnostic interest. Mechanical trauma generates cellular deformation associated with membrane permeability with unknown molecular consequences. We used an in vitro model of stretch-injury and proteomic analyses to determine protein changes in murine astrocytes and their surrounding fluids. Abrupt pressure-pulse stretching resulted in the rapid release of 59 astrocytic proteins with profiles reflecting cell injury and cell death, i.e., mechanoporation and cell lysis. This acute trauma-release proteome was overrepresented with metabolic proteins compared with the uninjured cellular proteome, bearing relevance for post-traumatic metabolic depression. Astrocyte-specific deletion of signal transducer and activator of transcription 3 (STAT3-CKO) resulted in reduced stretch-injury tolerance, elevated necrosis and increased protein release. Consistent with more lysed cells, more protein complexes, nuclear and transport proteins were released from STAT3-CKO versus nontransgenic astrocytes. STAT3-CKO astrocytes had reduced basal expression of GFAP, lactate dehydrogenase B (LDHB), aldolase C (ALDOC), and astrocytic phosphoprotein 15 (PEA15), and elevated levels of tropomyosin (TPM4) and α actinin 4 (ACTN4). Stretching caused STAT3-dependent cellular depletion of PEA15 and GFAP, and its filament disassembly in subpopulations of injured astrocytes. PEA15 and ALDOC signals were low in injured astrocytes acutely after mouse spinal cord crush injury and were robustly expressed in reactive astrocytes 1 day postinjury. In contrast, α crystallin (CRYAB) was present in acutely injured astrocytes, and absent from uninjured and reactive astrocytes, demonstrating novel marker differences among postinjury astrocytes. These findings reveal a proteomic signature of traumatically-injured astrocytes reflecting STAT3-dependent cellular survival with potential diagnostic value.
authors.affiliation: Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California.
authors.forename: Jaclynn
authors.initials: J
authors.lastname: Levine
authors.affiliation: Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California.
authors.forename: Eunice
authors.initials: E
authors.lastname: Kwon
authors.affiliation: Department of Pharmacology and Toxicology, Hunter James Kelly Research Institute, School of Medicine and Biomedical Sciences, SUNY, University at Buffalo, NYS Center of Excellence, Buffalo, New York.
authors.forename: Pablo
authors.initials: P
authors.lastname: Paez
authors.affiliation: Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California.
authors.forename: Weihong
authors.initials: W
authors.lastname: Yan
authors.affiliation: Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California.
authors.forename: Gregg
authors.initials: G
authors.lastname: Czerwieniec
authors.affiliation: Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California.|Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California.|UCLA/DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Loo
authors.affiliation: Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California.
authors.forename: Michael V
authors.initials: MV
authors.lastname: Sofroniew
authors.affiliation: Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California.
authors.forename: Ina-Beate
authors.initials: IB
authors.lastname: Wanner
mesh_terms: D000818:Animals; D001057:Apolipoproteins E / Q000378:metabolism; D001253:Astrocytes / Q000378:metabolism*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D004195:Disease Models, Animal; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010446:Peptide Fragments / Q000378:metabolism; D040901:Proteomics; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013119:Spinal Cord Injuries / Q000473:pathology*; D013314:Stress, Mechanical; D059467:Transcriptome / Q000235:genetics*
chemical_list: D001057:Apolipoproteins E; D010446:Peptide Fragments; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; C579624:apolipoprotein E (133-149); D049452:Green Fluorescent Proteins
keywords: astrocyte; biomarker; mechanoporation; proteome; trauma