Dopamine Transporter, PhosphoSerine129 α-Synuclein and α-Synuclein Levels in Aged LRRK2 G2019S Knock-In and Knock-Out Mice

Domenicale, Chiara; Mercatelli, Daniela; Albanese, Federica; Novello, Salvatore; Vincenzi, Fabrizio; Varani, Katia; Morari, Michele

doi:10.3390/biomedicines10040881

Cited by 6 publications

(9 citation statements)

References 70 publications

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“…CLEC7A has been identified as a marker for disease-associated microglial states (7,8). Upon visualization of these cells through electron microscopy, we observed substantial evidence that these CLEC7A + microglia undertake severe phagocytic activity, particularly by the presence of extensive phagosomes, and accumulate protein aggregates which is slightly enhanced in the striatum of these mice (64). The CLEC7A + microglia had both typical and intermediate nuclear patterns and did not meet the classic criteria for DM—suggesting that DM may downregulate CLEC7A in the current context, although the immunostaining might have masked the cell’s electron density, which warrants further examination.…”

Section: Discussionmentioning

confidence: 99%

Investigation of microglial diversity in a mouse model of Parkinson’s disease pathology

Iovino,

VanderZwaag,

Kaur

et al. 2023

Preprint

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Microglia, the central nervous system resident immune cells, are now recognized to critically impact homeostasis maintenance and contribute to the outcomes of various pathological conditions including Parkinson’s disease (PD). Microglia are heterogenous, with a variety of states recently identified in aging and neurodegenerative disease models, including the ‘disease-associated microglia’ (DAM) which present a selective enrichment ofCLEC7Aencoding the CLEC7A or DECTIN1 protein, and the ‘dark microglia’ (DM) displaying markers of cellular stress at the ultrastructural level. However, the roles of CLEC7A-positive microglia and DM in the pathology of PD have remained largely elusive. By applying immunofluorescence and scanning electron microscopy, we aimed to characterize 1) the CLEC7A -positive cell population, and 2) their possible relationships to DM in a mouse model harboring a G2019S pathogenic mutation of the LRRK2 gene, the most common mutation linked to PD. We examined 18-month-old mice, comparing between LRRK2 G2019S knock-in mice and wild-type controls. In the dorsal striatum, a region affected by PD pathology, extensive ultrastructural features of cellular stress (e.g., endoplasmic reticulum and Golgi apparatus dilation), as well as reduced direct cellular contacts, were observed for microglia from LRRK2 G2019S miceversuscontrols. CLEC7A-positive microglia exhibited extensive phagocytic ultrastructural characteristics in the LRRK2 G2019S mice. Additionally, the LRRK2 G2019S mice presented a higher proportion of DM. Lastly, immunofluorescence and biochemical analysis revealed higher number of CLEC7A-positive cells in Lrrk2 G2019S genotypeversuscontrols both in tissues and in primary microglia cells. Of note, CLEC7A-positive cells present a selective enrichment of ameboid morphology and tend to cluster in the pathogenic animal. In summary, we provide novel insights into the involvement of recently-defined microglial states, CLEC7A-positive cells and DM, in the context of LRRK2 G2019S PD pathology.

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Section: Discussionmentioning

confidence: 99%

Investigation of microglial diversity in a mouse model of Parkinson’s disease pathology

Iovino,

VanderZwaag,

Kaur

et al. 2023

Preprint

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“…LRRK2 G2019S mutant knock-in (GKI) mice show a significant increase in striatal DAT protein as assessed by western blot ( Longo et al, 2017 ; Volta et al, 2017 ; Domenicale et al, 2022 ) and dopamine uptake ( Longo et al, 2017 ; Domenicale et al, 2022 ). These changes to DAT levels are observed in LRRK2 G2019S mutants but not LRRK2 kinase-dead or knock-out mice ( Domenicale et al, 2022 ).…”

Section: Preclinical Evidencementioning

confidence: 99%

Selective dopaminergic vulnerability in Parkinson’s disease: new insights into the role of DAT

Harraz

2023

Front. Neurosci.

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One of the hallmarks of Parkinson’s disease (PD) is the progressive loss of dopaminergic neurons and associated dopamine depletion. Several mechanisms, previously considered in isolation, have been proposed to contribute to the pathophysiology of dopaminergic degeneration: dopamine oxidation-mediated neurotoxicity, high dopamine transporter (DAT) expression density per neuron, and autophagy-lysosome pathway (ALP) dysfunction. However, the interrelationships among these mechanisms remained unclear. Our recent research bridges this gap, recognizing autophagy as a novel dopamine homeostasis regulator, unifying these concepts. I propose that autophagy modulates dopamine reuptake by selectively degrading DAT. In PD, ALP dysfunction could increase DAT density per neuron, and enhance dopamine reuptake, oxidation, and neurotoxicity, potentially contributing to the progressive loss of dopaminergic neurons. This integrated understanding may provide a more comprehensive view of aspects of PD pathophysiology and opens new avenues for therapeutic interventions.

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“…No change was reported in the midbrain or other brain regions of G2019S KI mice up to 20 months [ 62 , 63 ]. An increase of pSer129 α-syn levels was observed in striatal homogenates of 12-month-old G2019S KI mice which, however, was not confirmed using DAB immunohistochemistry in striatal slices [ 69 ]. Most R1441C/G KI mice did not show changes of α-syn levels up to 28 months [ 65–67 ].…”

Section: Pd Neuropathologymentioning

confidence: 99%

“…A careful [ 3 H]-DA uptake analysis in G2019S KI mice, instead, showed an age-dependent 2-fold elevation of V max in a striatal synaptosomal preparation from G2019S KI mice compared with WT mice ( Table 4 ). This increase was significant from 9 through 18 months of age and was not paralleled by changes in K m , indicating no changes in transporter affinity for DA [ 64 , 69 ]. Acute administration of MLi-2 (10 mg/kg, i.p.)…”

Section: Neurotransmissionmentioning

confidence: 99%

“…Acute administration of MLi-2 (10 mg/kg, i.p.) could not affect V max elevation in G2019S KI mice, possibly suggesting it was not sustained by ongoing LRRK2 activity [ 69 ]. Functional DAT changes came along with an increase in striatal DAT protein levels although this was observed in a narrower time frame (9 and 12 months) [ 64 , 69 , 70 ].…”

Section: Neurotransmissionmentioning

confidence: 99%

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Modeling Parkinson’s disease in LRRK2 rodents

Domenicale,

Magnabosco,

Morari

2023

Neuronal Signaling

Self Cite

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Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are associated with familial and sporadic forms of Parkinson’s disease (PD). Sporadic PD and LRRK2 PD share main clinical and neuropathological features, namely hypokinesia, degeneration of nigro-striatal dopamine neurons and α-synuclein aggregates in the form of Lewy bodies. Animals harboring the most common LRRK2 mutations, i.e. G2019S and R1441C/G, have been generated to replicate the parkinsonian phenotype and investigate the underlying pathogenic mechanisms. Disappointingly, however, LRRK2 rodents did not consistently phenocopy hypokinesia and nigro-striatal degeneration, or showed Lewy body-like aggregates. Instead, LRRK2 rodents manifested non-motor signs and dysregulated transmission at dopaminergic and non-dopaminergic synapses that are reminiscent of behavioral and functional network changes observed in the prodromal phase of the disease. LRRK2 rodents also manifested greater susceptibility to different parkinsonian toxins or stressors when subjected to dual-hit or multiple-hit protocols, confirming LRRK2 mutations as genetic risk factors. In conclusion, LRRK2 rodents represent a unique tool to identify the molecular mechanisms through which LRRK2 modulates the course and clinical presentations of PD and to study the interplay between genetic, intrinsic and environmental protective/risk factors in PD pathogenesis.

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Dopamine Transporter, PhosphoSerine129 α-Synuclein and α-Synuclein Levels in Aged LRRK2 G2019S Knock-In and Knock-Out Mice

Cited by 6 publications

References 70 publications

Investigation of microglial diversity in a mouse model of Parkinson’s disease pathology

Investigation of microglial diversity in a mouse model of Parkinson’s disease pathology

Selective dopaminergic vulnerability in Parkinson’s disease: new insights into the role of DAT

Modeling Parkinson’s disease in LRRK2 rodents

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