Return to search

A glutaminyl cyclase‑catalyzed α‑synuclein modification identified in human synucleinopathies

Parkinson’s disease (PD) is a progressive neurodegenerative disorder that is neuropathologically characterized by degeneration
of dopaminergic neurons of the substantia nigra (SN) and formation of Lewy bodies and Lewy neurites composed of
aggregated α-synuclein. Proteolysis of α-synuclein by matrix metalloproteinases was shown to facilitate its aggregation and
to affect cell viability. One of the proteolysed fragments, Gln79-α-synuclein, possesses a glutamine residue at its N-terminus.
We argue that glutaminyl cyclase (QC) may catalyze the pyroglutamate (pGlu)79-α-synuclein formation and, thereby, contribute
to enhanced aggregation and compromised degradation of α-synuclein in human synucleinopathies. Here, the kinetic
characteristics of Gln79-α-synuclein conversion into the pGlu-form by QC are shown using enzymatic assays and mass
spectrometry. Thioflavin T assays and electron microscopy demonstrated a decreased potential of pGlu79-α-synuclein to
form fibrils. However, size exclusion chromatography and cell viability assays revealed an increased propensity of pGlu79-
α-synuclein to form oligomeric aggregates with high neurotoxicity. In brains of wild-type mice, QC and α-synuclein were
co-expressed by dopaminergic SN neurons. Using a specific antibody against the pGlu-modified neo-epitope of α-synuclein,
pGlu79-α-synuclein aggregates were detected in association with QC in brains of two transgenic mouse lines with human
α-synuclein overexpression. In human brain samples of PD and dementia with Lewy body subjects, pGlu79-α-synuclein
was shown to be present in SN neurons, in a number of Lewy bodies and in dystrophic neurites. Importantly, there was a
spatial co-occurrence of pGlu79-α-synuclein with the enzyme QC in the human SN complex and a defined association of
QC with neuropathological structures. We conclude that QC catalyzes the formation of oligomer-prone pGlu79-α-synuclein
in human synucleinopathies, which may—in analogy to pGlu-Aβ peptides in Alzheimer’s disease—act as a seed for pathogenic
protein aggregation.

Identiferoai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:93686
Date11 September 2024
CreatorsHartlage‑Rübsamen, Maike, Bluhm, Alexandra, Moceri, Sandra, Machner, Lisa, Köppen, Janett, Schenk, Mathias, Hilbrich, Isabel, Holzer, Max, Weidenfeller, Martin, Richter, Franziska, Coras, Roland, Serrano, Geidy E., Beach, Thomas G., Schilling, Stephan, von Hörsten, Stephan, Xiang, Wei, Schulze, Anja, Roßner, Steffen
PublisherSpringer
Source SetsHochschulschriftenserver (HSSS) der SLUB Dresden
LanguageEnglish
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/publishedVersion, doc-type:article, info:eu-repo/semantics/article, doc-type:Text
Rightsinfo:eu-repo/semantics/openAccess
Relation10.1007/s00401-021-02349-5

Page generated in 0.0018 seconds