Canagliflozin attenuates neurodegeneration and ameliorates dyskinesia through targeting the NLRP3/Nurr1/GSK-3β/SIRT3 pathway and autophagy modulation in rotenone-lesioned rats

Despite a deep understanding of Parkinson's disease (PD) and levodopa-induced dyskinesia (LID) pathogenesis, current therapies are insufficient to effectively manage the progressive nature of PD or halt LID. Growing hypotheses suggested the NOD-like receptor 3 (NLRP3) inflammasome and orphan nuclear receptor-related 1 (Nurr1)/glycogen synthase kinase-3β (GSK-3β) and peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α)/sirtuin 3 (SIRT3) pathways as potential avenues for halting neuroinflammation and oxidative stress in PD.

Aims: This study investigated for the first time the neuroprotective effect of canagliflozin against PD and LID in rotenone-intoxicated rats, emphasizing the crosstalk among the NLRP3/caspase-1 cascade, PGC-1α/SIRT3 pathway, mammalian target of rapamycin (mTOR)/beclin-1, and Nurr1/β-catenin/GSK-3β pathways as possible treatment strategies in PD and LID. Also, correlating NLRP3 expression with all evaluated parameters.

Main methods: The PD rat model was induced via eleven rotenone (1.5 mg/kg) subcutaneous injections day after day. Canagliflozin (20 mg/kg) and/or L-dopa/carbidopa (100/25 mg/kg) were orally administered daily from the beginning until the end of the experiment.

Key findings: Canagliflozin significantly improved neurobehavioral and histological assessments, whereas dyskinesia scores declined. The improvement was confirmed through tyrosine hydroxylase and β-catenin upregulation in contrast to NLRP3 and caspase-1 in substantia nigra pars compacta, as revealed immunohistochemically. In addition, canagliflozin induced a prominent elevation in dopamine, Nurr1, PGC-1α, SIRT3, and beclin-1, whereas mTOR and GSK-3β expressions were downregulated.

Significance: Our results revealed the aspiring canagliflozin neuroprotective properties against PD and LID in rotenone-lesioned rats via the assumed anti-inflammatory activity and implication of NLRP3/caspase-1, Nurr1/GSK-3β/β-catenin, PGC-1α/SIRT3, and beclin-1/mTOR pathways.