Lewy body dementia

GALNT9 enrichment attenuates MPP+-induced cytotoxicity by ameliorating protein aggregations containing α-synuclein and mitochondrial dysfunction

BACKGROUND

GALNTs (UDP-GalNAc; polypeptide N-acetylgalactosaminyltransferases) initiate mucin-type O-GalNAc glycosylation by adding N-GalNAc to protein serine/threonine residues. Abnormalities in O-GalNAc glycosylation are involved in various disorders such as Parkinson's disease (PD), a neurodegenerative disorder. GALNT9 is potentially downregulated in PD patients.

METHODS

To determine whether GALNT9 enrichment ameliorates cytotoxicity related to PD-like variations, a pcDNA3.1-GALNT9 plasmid was constructed and transfected into SH-SY5Y cells to establish a GALNT9-overexpressing cell model.

RESULTS

Downregulation of GALNT9 and O-GalNAc glycosylation was confirmed in our animal and cellular models of PD-like variations. GALNT9 supplementation greatly attenuated cytotoxicity induced by MPP+ (1-Methyl-4-phenylpyridinium iodide) since it led to increased levels of tyrosine hydroxylase and dopamine, reduced rates of apoptosis, and significantly ameliorated MPP+-induced mitochondrial dysfunction by alleviating abnormal levels of mitochondrial membrane potential and reactive oxygen species. A long-lasting mPTP (mitochondrial permeability transition pores) opening and calcium efflux resulted in significantly lower activity in the cytochrome C-associated apoptotic pathway and mitophagy process, signifying that GALNT9 supplementation maintained neuronal cell health under MPP+ exposure. Additionally, it was found that glycans linked to proteins influenced the formation of protein aggregates containing α-synuclein, and GALNT9 supplement dramatically reduced such insoluble protein aggregations under MPP+ treatment. Glial GALNT9 predominantly appears under pathological conditions like PD-like variations.

CONCLUSIONS

GALNT9 enrichment improved cell survival, and glial GALNT9 potentially represents a pathogenic index for PD patients. This study provides insights into the development of therapeutic strategies for the treatment of PD.

Sleep physiology and disorders in aging and dementia

Sleep problems occur commonly in normal and pathologic aging. Older adults typically have more difficulty falling asleep and remaining asleep, report more daytime napping, and have an increased prevalence of primary sleep disorders such as insomnia, parasomnias, sleep apnea, and sleep-related movement disorders. Medical and psychiatric disorders as well as medications used to treat them also contribute to sleep disturbances in aging. Patients with mild cognitive impairment and dementia have more severe sleep problems, and disturbed sleep and sleep disorders contribute to earlier onset and more rapid progression of neurodegenerative disorders. Approaches to diagnosing and treating sleep disorders in the elderly are discussed.

Treatment of psychosis in elderly people

Psychotic symptoms in elderly people can be seen in a variety of conditions. This article reviews treatment strategies (both pharmacological and non-pharmacological) for such symptoms in schizophrenia and neurodegenerative disorders in this population. Traditionally, antipsychotics have been the most commonly used treatment for psychotic symptoms. Their usefulness in treating schizophrenia, both chronic and late onset, is well established and the atypical antipsychotics, which have a better side-effect profile, are more suitable for elderly people. More recently, there have been increasing concerns about their safety in psychoses due to dementia. The debate about whether an absolute ban on their use is required is still ongoing, but it has highlighted the need for adopting and developing non-pharmacological interventions.

Rivastigmine in Parkinson's disease dementia

Parkinson's disease has now evolved beyond what was considered to be a traditional motor disorder. It is being increasingly recognized that non-motor symptoms such as cognitive impairment, frank dementia, psychosis, depression, autonomic dysfunction and sleep disturbances are just as integral to the disease spectrum. The cholinergic system has been proposed to play a pivotal role in cognitive dysfunction. Based on interpretation of clinical studies in patients with Alzheimer's, cholinesterase inhibitors have also been studied for dementia associated with Parkinson's disease. Most of these include large and small placebo-controlled studies and several pilot studies have indicated that cholinesterase inhibitors have a favorable effect on cognition, psychiatric symptoms and global function in Parkinson's disease dementia. A large randomized placebo-controlled clinical trial showed that rivastigmine had moderate improvement in dementia associated with Parkinson's disease. The magnitude of effects in terms of scores for the cognitive subscale of the Alzheimer's disease assessment scale and Alzheimer's disease cooperative study-clinicians global impression of change were similar to those observed among patients with Alzheimer's disease who were treated with cholinesterase inhibitors. A transdermal patch which gradually releases rivastigmine over the application period is now available for use in mild to moderate dementia associated with Parkinson's disease and Alzheimer's disease.

TorsinA accumulation in Lewy bodies in sporadic Parkinson's disease

Parkinson's disease (PD) is a neurodegnerative disorder that is pathologically characterized by the presence of Lewy bodies in the brain. We show that Lewy bodies in PD are strongly immunoreactive for torsinA, the protein product of the DYT1 gene, which is associated with primary generalized dystonia. In the substantia nigra, torsinA immunoreactivity is localized to the periphery of Lewy bodies, whereas, in cortical Lewy bodies it is uniformly distributed. The significance of this finding is unknown, but may implicate torsinA in neuronal dysfunction that occurs in PD as well as in primary dystonia.

Did Don Quixote have Lewy body disease?

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