Biology subjects

Christensen, K. V.

Publications and source records attributed to Christensen, K. V..

3 recordsLinked to original sources

bioRxiv2021

Synergistic Effect of Serotonin 1A and Serotonin 1B/D Receptor Agonists in the Treatment of L-DOPA-Induced Dyskinesia in 6-Hydroxydopamine-Lesioned Rats

BackgroundThe gold standard for symptomatic relief of Parkinsons disease is L-DOPA. However, long-term treatment often leads to motor complications such as L-DOPA-induced dyskinesia (LID). While amantadine (Gocovri) is the only approved therapy for dyskinesia in people with Parkinsons disease on the American market, it is associated with neurological side effects and limited efficacy. Thus, there remains a high unmet need for addressing LID in Parkinsons disease patients worldwide. ObjectiveThe objective of this study was to evaluate the efficacy, safety and performance compared to approved treatments of the serotonin receptor 1A (5-HT1A) and 5-HT1B/D agonists buspirone and zolmitriptan in the 6-hydroxydopamine unilaterally lesioned rat model for Parkinsons disease. MethodsThe hemi-parkinsonian 6-OHDA lesioned rats underwent chronic treatment with L-DOPA to induce dyskinesia and were subsequently used for efficacy testing of buspirone, zolmitriptan and comparison with amantadine, measured as abnormal involuntary movement (AIM) scores after L-DOPA challenge. Safety testing was performed in model and naive animals using forelimb adjusting, rotarod and open field tests. Results5-HT1A and 5-HT1B/D agonism effectively reduced AIM scores in a synergistic manner. The drug combination of buspirone and zolmitriptan was safe and did not lead to tolerance development following sub-chronic administration. Head-to-head comparison with amantadine showed superior performance of buspirone and zolmitriptan in the model. ConclusionsThe strong anti-dyskinetic effect found with combined 5-HT1A and 5-HT1B/D agonism renders buspirone and zolmitriptan a potential clinical candidate for LID in Parkinsons disease.

neuroscience↗

bioRxiv2018

Long-term exposure to PFE-360 in the AAV-α-synuclein rat model: findings and implications

Significance statementTreatment of Parkinsons disease is reliant on symptomatic treatments, without any option to slow or halt disease progression. Mutations in LRRK2 and -synuclein are known risk factors for Parkinsons disease. Presence of -synuclein aggregates at autopsies in both idiopathic and most G2019S cases is suggestive of a common disease pathogenesis. LRRK2 and -synuclein interaction is hypothesized to play a pivotal role in the pathological mechanisms and inhibitors of LRRK2 are investigated as novel disease modulatory treatments in the clinic. However, preclinical in vivo evidence of a beneficial effect of LRRK2 inhibition is mixed and limited. This study increases our understanding of LRRK2 as a mediator of neuronal dysfunction and the potential of LRRK2 as a promising target in PD.

neuroscience↗

bioRxiv2018

LRRK2 exonic variants associated with Parkinson’s disease augment phosphorylation levels for LRRK2-Ser1292 and Rab10-Thr73

Leucine-rich repeat kinase 2 (LRRK2) is associated to Parkinsons disease (PD). The most common form of LRRK2 PD is caused by the G2019S variant. Besides G2019S, eight other LRRK2 variants causing familial PD also have amino acid substitutions located in a LRRK2 enzymatic domainsuggesting that enzymatic activity is at the core of mechanisms underlying disease risk. Common LRRK2 polymorphic risk variations such as G2385R, A419V, R1628 and M1646T all reside in other LRRK2 domains. Prior knowledge is limited on how these variants influence LRRK2 function. To investigate the impact on enzymatic function of both rare and common LRRK2 variation a comprehensive profiling of nineteen LRRK2 exonic variants was pursued. Six LRRK2 phosphorylation sites were identified by mass spectrometry. Besides already known phosphorylation sites such as Ser910, Ser935, Ser955, Ser973 and Ser1292 also Thr826 was confirmed by a targeted MRM assay as a LRRK2 phosphorylation site in mammalian cells. Phosphorylation site occupancy for all six LRRK2 sites was obtained but no obvious correlation to risk of disease was found. Instead, application of phospho-specific antibodies targeting LRRK2 phosphorylation sites confirmed that autophosphorylation at Ser1292 was significantly increased for all disease-causing variants whereas no significant differences could be observed for the common intermediate risk variants. Recently, Rab10 and Rab12 have been shown to be bona fide LRRK2 substrates and we find that both rare and common LRRK2 exonic variants augment the phosphorylation of Rab10. This was not observed with Rab12. Furthermore, the protective variant N551K has reduced Rab10 phosphorylation compared to LRRK2 WT. This was not observed with the protective variant R1398H. Our findings support the hypothesis that increased LRRK2 kinase function is associated with increased PD risk but also highlights the need for more sensitive tools for detection of increases in kinase activity in carriers of LRRK2 PD risk variants.\n\nAbbreviations

biochemistry↗