Inducible neuronal expression of transgenic TGF-beta1 in vivo: dissection of short-term and long-term effects.
Various chronic neurological diseases are associated with increased expression of transforming growth factor-beta1 (TGF-beta1) in the brain. TGF-beta1 has both neuroprotective and neurodegenerative functions, depending on conditions such as duration and the local and temporal pattern of its expression. Previous transgenic approaches did not enable control for these dynamic aspects. To overcome these limitations, we established a transgenic mouse model with inducible neuron-specific expression of TGF-beta1 based on the tetracycline-regulated gene expression system. TGF-beta1 expression was restricted to the brain where it was particularly pronounced in the neocortex, hippocampus and striatum. Transgene expression was highly sensitive to the presence of doxycycline and completely silenced within 6 days after doxycycline application. After long-term expression, perivascular thioflavin-positive depositions, formed by amyloid fibrils, developed. These depositions persisted even after prolonged silencing of the transgene, indicating an irreversible process. Similarly, strong perivascular apolipoprotein E (ApoE) depositions were found after TGF-beta1 expression and these remained despite TGF-beta1 removal. These in vivo observations suggests that the continuous presence of TGF-beta1 as initial trigger is not necessary for the persistence and development of chronic lesions. Neuroprotective effects were observed after short-term expression of TGF-beta1. Death of striatal neurons induced by 3-nitropropionic acid was markedly reduced after induced TGF-beta1 expression.
Ueberham
Uwe
U
Paul Flechsig Institute for Brain Research, Department of Neuroanatomy, University of Leipzig, Jahnallee 59, D-04109 Leipzig, Germany. uebu@medizin.uni-leipzig.de
Ueberham
Elke
E
Brückner
Martina K
MK
Seeger
Gudrun
G
Gärtner
Ulrich
U
Gruschka
Hildegard
H
Gebhardt
Rolf
R
Arendt
Thomas
T
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001057:Apolipoproteins E / Q000235:genetics; D052160:Benzothiazoles; D001921:Brain / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D004318:Doxycycline / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000235:genetics; D020868:Gene Silencing / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic; D008967:Molecular Biology / Q000379:methods; D009410:Nerve Degeneration / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism*; D019636:Neurodegenerative Diseases / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D018696:Neuroprotective Agents / Q000378:metabolism; D009498:Neurotoxins / Q000494:pharmacology; D009574:Nitro Compounds; D058225:Plaque, Amyloid / Q000235:genetics / Q000378:metabolism; D011422:Propionates / Q000494:pharmacology; D013844:Thiazoles / Q000378:metabolism; D014162:Transfection / Q000379:methods; D016212:Transforming Growth Factor beta / Q000096:biosynthesis* / Q000235:genetics; D053773:Transforming Growth Factor beta1; D019076:Transgenes / Q000235:genetics
D000900:Anti-Bacterial Agents; D001057:Apolipoproteins E; D052160:Benzothiazoles; D018696:Neuroprotective Agents; D009498:Neurotoxins; D009574:Nitro Compounds; D011422:Propionates; C508961:Tgfb1 protein, mouse; D013844:Thiazoles; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C009462:thioflavin T; D004318:Doxycycline; C015392:3-nitropropionic acid