title: Induction of autophagy by cystatin C: a mechanism that protects murine primary cortical neurons and neuronal cell lines.
abstract: Cystatin C (CysC) expression in the brain is elevated in human patients with epilepsy, in animal models of neurodegenerative conditions, and in response to injury, but whether up-regulated CysC expression is a manifestation of neurodegeneration or a cellular repair response is not understood. This study demonstrates that human CysC is neuroprotective in cultures exposed to cytotoxic challenges, including nutritional-deprivation, colchicine, staurosporine, and oxidative stress. While CysC is a cysteine protease inhibitor, cathepsin B inhibition was not required for the neuroprotective action of CysC. Cells responded to CysC by inducing fully functional autophagy via the mTOR pathway, leading to enhanced proteolytic clearance of autophagy substrates by lysosomes. Neuroprotective effects of CysC were prevented by inhibiting autophagy with beclin 1 siRNA or 3-methyladenine. Our findings show that CysC plays a protective role under conditions of neuronal challenge by inducing autophagy via mTOR inhibition and are consistent with CysC being neuroprotective in neurodegenerative diseases. Thus, modulation of CysC expression has therapeutic implications for stroke, Alzheimer's disease, and other neurodegenerative disorders.
authors.affiliation: Nathan S. Kline Institute, Orangeburg, New York, United States of America.
authors.forename: Belen
authors.initials: B
authors.lastname: Tizon
authors.forename: Susmita
authors.initials: S
authors.lastname: Sahoo
authors.forename: Haung
authors.initials: H
authors.lastname: Yu
authors.forename: Sebastien
authors.initials: S
authors.lastname: Gauthier
authors.forename: Asok R
authors.initials: AR
authors.lastname: Kumar
authors.forename: Panaiyur
authors.initials: P
authors.lastname: Mohan
authors.forename: Matthew
authors.initials: M
authors.lastname: Figliola
authors.forename: Monika
authors.initials: M
authors.lastname: Pawlik
authors.forename: Anders
authors.initials: A
authors.lastname: Grubb
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Uchiyama
authors.forename: Urmi
authors.initials: U
authors.lastname: Bandyopadhyay
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Cuervo
authors.forename: Ralph A
authors.initials: RA
authors.lastname: Nixon
authors.forename: Efrat
authors.initials: E
authors.lastname: Levy
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000378:metabolism; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy; D000071186:Beclin-1; D002460:Cell Line; D003078:Colchicine / Q000494:pharmacology; D055316:Cystatin C / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008247:Lysosomes / Q000378:metabolism; D051379:Mice; D019636:Neurodegenerative Diseases / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D019311:Staurosporine / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D050257:Tubulin Modulators / Q000494:pharmacology
chemical_list: D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; C115010:Becn1 protein, mouse; C512829:Becn1 protein, rat; D055316:Cystatin C; D004791:Enzyme Inhibitors; D050257:Tubulin Modulators; C025946:3-methyladenine; D058570:TOR Serine-Threonine Kinases; D019311:Staurosporine; D000225:Adenine; D003078:Colchicine