Blocking meningeal lymphatic drainage aggravates Parkinson’s disease-like pathology in mice overexpressing mutated α-synuclein

Background:Abnormal aggregation of brainα-synuclein is a central step in the pathogenesis of Parkinson’s disease(PD),thus,it is reliable to promote the clearance ofα-synuclein to prevent and treat PD.Recent studies have revealed an essential role of glymphatic system and meningeal lymphatic vessels in the clearance of brain macromolecules,however,their pathophysiological aspects remain elusive.Method:Meningeal lymphatic drainage of 18-week-old A53T mice was blocked via ligating the deep cervical lymph nodes.Six weeks later,glymphatic functions and PD-like phenotypes were systemically analyzed.Results:Glymphatic influx of cerebrospinal fluid tracer was reduced in A53T mice,accompanied with perivascular aggregation ofα-synuclein and impaired polarization of aquaporin 4 expression in substantia nigra.Cervical lymphatic ligation aggravated glymphatic dysfunction of A53T mice,causing more severe accumulation ofα-synuclein,glial activation,inflammation,dopaminergic neuronal loss and motor deficits.Conclusion:The results suggest that brain lymphatic clearance dysfunction may be an aggravating factor in PD pathology.