The accumulation of abnormal protein aggregates is a major characteristic of many neurodegenerative disorders, including Parkinson's disease (PD). The intracytoplasmic deposition of alpha-synuclein aggregates and Lewy bodies, often found in PD and other alpha-synucleinopathies, is thought to be linked to inefficient cellular clearance mechanisms, such as the proteasome and autophagy/lysosome pathways. The accumulation of alpha-synuclein aggregates in neuronal cytoplasm causes numerous autonomous changes in neurons. However, it can also affect the neighboring cells through transcellular transmission of the aggregates. Indeed, a progressive spreading of Lewy pathology among brain regions has been hypothesized from autopsy studies. We tested whether inhibition of the autophagy/lysosome pathway in alpha-synuclein-expressing cells would increase the secretion of alpha-synuclein, subsequently affecting the alpha-synuclein deposition in and viability of neighboring cells. Our results demonstrated that autophagic inhibition, via both pharmacological and genetic methods, led to increased exocytosis of alpha-synuclein. In a mixed culture of alpha-synuclein-expressing donor cells with recipient cells, autophagic inhibition resulted in elevated transcellular alpha-synuclein transmission. This increase in protein transmission coincided with elevated apoptotic cell death in the recipient cells. These results suggest that the inefficient clearance of alpha-synuclein aggregates, which can be caused by reduced autophagic activity, leads to elevated alpha-synuclein exocytosis, thereby promoting alpha-synuclein deposition and cell death in neighboring neurons. This finding provides a potential link between autophagic dysfunction and the progressive spread of Lewy pathology.
Adenine/analogs & derivatives/pharmacology ; Animals ; *Autophagy/drug effects ; Cell Line ; *Exocytosis/drug effects ; Extracellular Space/*metabolism ; Humans ; Mice ; Mice, Knockout ; Microtubule-Associated Proteins/deficiency/metabolism ; Phagosomes/drug effects/metabolism ; Protein Structure, Quaternary ; Protein Transport/drug effects ; alpha-Synuclein/chemistry/*metabolism/secretion/toxicity

Background and Objectives: MYC, also known as an oncogenic reprogramming factor, is a multifunctional transcription factor that maintains induced pluripotent stem cells (iPSCs). Although MYC is frequently upregulated in various cancers and is correlated with a poor prognosis, MYC is downregulated and correlated with a good prognosis in lung adenocarcinoma. MYC and two other MYC family genes, MYCN and MYCL, have similar structures and could contribute to tumorigenic conversion both in vitro and in vivo. Methods: and Results: We systematically investigated whether MYC family genes act as prognostic factors in various human cancers. We first evaluated alterations in the expression of MYC family genes in various cancers using the Oncomine and The Cancer Genome Atlas (TCGA) database and their mutation and copy number alterations using the TCGA database with cBioPortal. Then, we investigated the association between the expression of MYC family genes and the prognosis of cancer patients using various prognosis databases. Multivariate analysis also confirmed that co-expression of MYC/MYCL/MYCN was significantly associated with the prognosis of lung, gastric, liver, and breast cancers. Conclusions Taken together, our results demonstrate that the MYC family can function not only as an oncogene but also as a tumor suppressor gene in various cancers, which could be used to develop a novel approach to cancer treatment.

Background and Objectives: Flavonoids form the largest group of plant phenols and have various biological and pharma-cological activities. In this study, we investigated the effect of a flavonoid, 3, 4’-dihydroxyflavone (3, 4’-DHF) on osteogenic differentiation of equine adipose-derived stromal cells (eADSCs). Methods: and Results: Treatment of 3, 4’-DHF led to increased osteogenic differentiation of eADSCs by increasing phosphorylation of ERK and modulating Reactive Oxygen Species (ROS) generation. Although PD98059, an ERK inhibitor, suppressed osteogenic differentiation, another ERK inhibitor, U0126, apparently increased osteogenic differentiation of the 3, 4’-DHF-treated eADSCs, which may indicate that the effect of U0126 on bone morphogenetic protein signaling is involved in the regulation of 3, 4’-DHF in osteogenic differentiation of eADSCs. We revealed that 3, 4’-DHF could induce osteogenic differentiation of eADSCs by suppressing ROS generation and co-treatment of 3, 4’-DHF, U0126, and/or N-acetyl cysteine (NAC) resulted in the additive enhancement of osteogenic differentiation of eADSCs. Conclusions Our results showed that co-treatment of 3, 4’-DHF, U0126, and/or NAC cumulatively regulated osteo-genesis in eADSCs, suggesting that 3, 4’-DHF, a flavonoid, can provide a novel approach to the treatment of osteoporosis and can provide potential therapeutic applications in therapeutics and regenerative medicine for human and companion animals.