title: Attenuation of astrocyte activation by TAT-mediated delivery of a peptide JNK inhibitor.
abstract: Astrocyte activation contributes to the brain's response to disease and injury. Activated astrocytes generate harmful radicals that exacerbate brain damage including nitric oxide, peroxides and superoxides. Furthermore, reactive astrocytes hinder regeneration of damaged neural circuits by secreting neuro-developmental inhibitors and glycosaminoglycans (GAGs), which physically block growth cone extension. Therefore, targeted therapeutic strategies to limit astrocyte activation may enhance recovery from many neurodegenerative states. Previously, we demonstrated that the HIV-1 TAT cell-penetrating peptide, a short non-toxic peptide from the full-length TAT protein, delivered a protein cargo to astrocytes in a process dependent on cell-surface GAG. Since activated astrocytes produce GAG, in this study we tested whether TAT could transduce activated astrocytes, deliver a biologically active cargo, and produce a physiological effect. Astrocyte activation was induced by IL-1β, lipopolysaccharide (LPS), or mechanical stretch injury, and quantified by increased GAG and nitrite content. TAT-mediated delivery of a mock therapeutic protein, GFP, increased significantly after activation. Nitrite production, GAG expression, and GFP-TAT transduction were significantly attenuated by inhibitors of JNK, p38, or ERK. TAT fused to a peptide JNK inhibitor delivered the peptide inhibitor to activated astrocytes and significantly reduced activation. Our study is the first to report significant and direct modulation of astrocyte activation with a peptide JNK inhibitor. Our promising in vitro results warrant in vivo follow-up, as TAT-mediated protein delivery may have broad therapeutic potential for preventing astrocyte activation with the possibility of limiting off-target, negative side effects.
authors.affiliation: Department of Biomedical, Columbia University, 1210 Amsterdam Avenue, New York, NY 10027, USA. bm2119@columbia.edu
authors.forename: Woo Hyeun
authors.initials: WH
authors.lastname: Kang
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Simon
authors.forename: Shan
authors.initials: S
authors.lastname: Gao
authors.forename: Scott
authors.initials: S
authors.lastname: Banta
authors.forename: Barclay
authors.initials: B
authors.lastname: Morrison
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D001693:Biological Transport, Active / Q000502:physiology; D016503:Drug Delivery Systems / Q000379:methods; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D005911:Gliosis / Q000188:drug therapy / Q000201:enzymology / Q000209:etiology; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D010455:Peptides / Q000502:physiology* / Q000627:therapeutic use; D047428:Protein Kinase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D014161:Transduction, Genetic; D016896:Treatment Outcome; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000378:metabolism / Q000502:physiology* / Q000627:therapeutic use
chemical_list: D010455:Peptides; D047428:Protein Kinase Inhibitors; D054322:tat Gene Products, Human Immunodeficiency Virus; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases