Knockout of PINK1 altered the neural connectivity of Drosophila dopamine PPM3 neurons at input and output sites

YWHAZ variation causes intellectual disability and global developmental delay with brain malformation

YWHAZ encodes an adapter protein 14-3-3ζ, which is involved in many signaling pathways that control cellular proliferation, migration and differentiation. It has not been definitely correlated to any phenotype in OMIM. To investigate the role of YWHAZ gene in intellectual disability and global developmental delay, we conducted whole-exon sequencing in all of the available members from a large three-generation family and we discovered that a novel variant of the YWHAZ gene was associated with intellectual disability and global developmental delay. This variant is a missense mutation of YWHAZ, p.Lys49Asn/c.147A > T, which was found in all affected members but not found in other unaffected members. We also conducted computational modeling and knockdown/knockin with Drosophila to confirm the role of the YWHAZ variant in intellectual disability. Computational modeling showed that the binding energy was increased in the mutated protein combining with the ligand indicating that the c147A > T variation was a loss-of-function variant. Cognitive defects and mushroom body morphological abnormalities were observed in YWHAZ c.147A > T knockin flies. The YWHAZ knockdown flies also manifested serious cognitive defects with hyperactivity behaviors, which is consistent with the clinical features. Our clinical and experimental results consistently suggested that YWHAZ was a novel intellectual disability pathogenic gene.

Ketone Body Rescued Seizure Behavior of LRP1 Deficiency in Drosophila by Modulating Glutamate Transport

LRP1, the low-density lipoprotein receptor 1, would be a novel candidate gene of epilepsy according to our bioinformatic results and the animal study. In this study, we explored the role of LRP1 in epilepsy and whether beta-hydroxybutyrate, the principal ketone body of the ketogenic diet, can treat epilepsy caused by LRP1 deficiency in drosophila. UAS/GAL4 system was used to establish different genotype models. Flies were given standard, high-sucrose, and ketone body food randomly. The bang-sensitive test was performed on flies and seizure-like behavior was assessed. In morphologic experiments, we found that LRP1 deficiency caused partial loss of the ellipsoidal body and partial destruction of the fan-shaped body. Whole-body and glia LRP1 defect flies had a higher seizure rate compared to the control group. Ketone body decreased the seizure rate in behavior test in all LRP1 defect flies, compared to standard and high sucrose diet. Overexpression of glutamate transporter gene Eaat1 could mimic the ketone body effect on LRP1 deficiency flies. This study demonstrated that LRP1 defect globally or in glial cells or neurons could induce epilepsy in drosophila. The ketone body efficaciously rescued epilepsy caused by LRP1 knockdown. The results support screening for LRP1 mutations as discriminating conduct for individuals who require clinical attention and further clarify the mechanism of the ketogenic diet in epilepsy, which could help epilepsy patients make a precise treatment case by case.

Peiminine Reduces ARTS-Mediated Degradation of XIAP by Modulating the PINK1/Parkin Pathway to Ameliorate 6-Hydroxydopamine Toxicity and α-Synuclein Accumulation in Parkinson's Disease Models In Vivo and In Vitro

Parkinson’s disease (PD) is a degenerative disease that can cause motor, cognitive, and behavioral disorders. The treatment strategies being developed are based on the typical pathologic features of PD, including the death of dopaminergic (DA) neurons in the substantia nigra of the midbrain and the accumulation of α-synuclein in neurons. Peiminine (PMN) is an extract of Fritillaria thunbergii Miq that has antioxidant and anti-neuroinflammatory effects. We used Caenorhabditis elegans and SH-SY5Y cell models of PD to evaluate the neuroprotective potential of PMN and address its corresponding mechanism of action. We found that pretreatment with PMN reduced reactive oxygen species production and DA neuron degeneration caused by exposure to 6-hydroxydopamine (6-OHDA), and therefore significantly improved the DA-mediated food-sensing behavior of 6-OHDA-exposed worms and prolonged their lifespan. PMN also diminished the accumulation of α-synuclein in transgenic worms and transfected cells. In our study of the mechanism of action, we found that PMN lessened ARTS-mediated degradation of X-linked inhibitor of apoptosis (XIAP) by enhancing the expression of PINK1/parkin. This led to reduced 6-OHDA-induced apoptosis, enhanced activity of the ubiquitin–proteasome system, and increased autophagy, which diminished the accumulation of α-synuclein. The use of small interfering RNA to down-regulate parkin reversed the benefits of PMN in the PD models. Our findings suggest PMN as a candidate compound worthy of further evaluation for the treatment of PD.