TY - JOUR
T1 - Autophagy inhibition promotes SNCA/alpha-synuclein release and transfer via extracellular vesicles with a hybrid autophagosome-exosome-like phenotype
AU - Minakaki, Georgia
AU - Menges, Stefanie
AU - Kittel, Agnes
AU - Emmanouilidou, Evangelia
AU - Schaeffner, Iris
AU - Barkovits, Katalin
AU - Bergmann, Anna
AU - Rockenstein, Edward
AU - Adame, Anthony
AU - Marxreiter, Franz
AU - Mollenhauer, Brit
AU - Galasko, Douglas
AU - Buzás, Edit Irén
AU - Schlötzer-Schrehardt, Ursula
AU - Marcus, Katrin
AU - Xiang, Wei
AU - Lie, Dieter Chichung
AU - Vekrellis, Kostas
AU - Masliah, Eliezer
AU - Winkler, Jürgen
AU - Klucken, Jochen
N1 - Publisher Copyright:
© 2018 Taylor & Francis.
PY - 2018/1/2
Y1 - 2018/1/2
N2 - The autophagy-lysosome pathway (ALP) regulates intracellular homeostasis of the cytosolic protein SNCA/alpha-synuclein and is impaired in synucleinopathies, including Parkinson disease and dementia with Lewy bodies (DLB). Emerging evidence suggests that ALP influences SNCA release, but the underlying cellular mechanisms are not well understood. Several studies identified SNCA in exosome/extracellular vesicle (EV) fractions. EVs are generated in the multivesicular body compartment and either released upon its fusion with the plasma membrane, or cleared via the ALP. We therefore hypothesized that inhibiting ALP clearance 1) enhances SNCA release via EVs by increasing extracellular shuttling of multivesicular body contents, 2) alters EV biochemical profile, and 3) promotes SNCA cell-to-cell transfer. Indeed, ALP inhibition increased the ratio of extra- to intracellular SNCA and upregulated SNCA association with EVs in neuronal cells. Ultrastructural analysis revealed a widespread, fused multivesicular body-autophagosome compartment. Biochemical characterization revealed the presence of autophagosome-related proteins, such as LC3-II and SQSTM1. This distinct “autophagosome-exosome-like” profile was also identified in human cerebrospinal fluid (CSF) EVs. After a single intracortical injection of SNCA-containing EVs derived from CSF into mice, human SNCA colocalized with endosome and neuronal markers. Prominent SNCA immunoreactivity and a higher number of neuronal SNCA inclusions were observed after DLB patient CSF EV injections. In summary, this study provides compelling evidence that a) ALP inhibition increases SNCA in neuronal EVs, b) distinct ALP components are present in EVs, and c) CSF EVs transfer SNCA from cell to cell in vivo. Thus, macroautophagy/autophagy may regulate EV protein composition and consequently progression in synucleinopathies.
AB - The autophagy-lysosome pathway (ALP) regulates intracellular homeostasis of the cytosolic protein SNCA/alpha-synuclein and is impaired in synucleinopathies, including Parkinson disease and dementia with Lewy bodies (DLB). Emerging evidence suggests that ALP influences SNCA release, but the underlying cellular mechanisms are not well understood. Several studies identified SNCA in exosome/extracellular vesicle (EV) fractions. EVs are generated in the multivesicular body compartment and either released upon its fusion with the plasma membrane, or cleared via the ALP. We therefore hypothesized that inhibiting ALP clearance 1) enhances SNCA release via EVs by increasing extracellular shuttling of multivesicular body contents, 2) alters EV biochemical profile, and 3) promotes SNCA cell-to-cell transfer. Indeed, ALP inhibition increased the ratio of extra- to intracellular SNCA and upregulated SNCA association with EVs in neuronal cells. Ultrastructural analysis revealed a widespread, fused multivesicular body-autophagosome compartment. Biochemical characterization revealed the presence of autophagosome-related proteins, such as LC3-II and SQSTM1. This distinct “autophagosome-exosome-like” profile was also identified in human cerebrospinal fluid (CSF) EVs. After a single intracortical injection of SNCA-containing EVs derived from CSF into mice, human SNCA colocalized with endosome and neuronal markers. Prominent SNCA immunoreactivity and a higher number of neuronal SNCA inclusions were observed after DLB patient CSF EV injections. In summary, this study provides compelling evidence that a) ALP inhibition increases SNCA in neuronal EVs, b) distinct ALP components are present in EVs, and c) CSF EVs transfer SNCA from cell to cell in vivo. Thus, macroautophagy/autophagy may regulate EV protein composition and consequently progression in synucleinopathies.
KW - Parkinson disease
KW - SNCA
KW - alpha-synuclein
KW - autophagosome
KW - cell-to-cell transfer
KW - cerebrospinal fluid
KW - dementia with Lewy bodies
KW - extracellular vesicles
KW - multivesicular body
KW - release
KW - synucleinopathies
UR - http://www.scopus.com/inward/record.url?scp=85040961874&partnerID=8YFLogxK
U2 - 10.1080/15548627.2017.1395992
DO - 10.1080/15548627.2017.1395992
M3 - Article
C2 - 29198173
AN - SCOPUS:85040961874
SN - 1554-8627
VL - 14
SP - 98
EP - 119
JO - Autophagy
JF - Autophagy
IS - 1
ER -