Ataxin-3, The Spinocerebellar Ataxia Type 3 Neurodegenerative Disorder Protein, Affects Mast Cell Functions

Natural diterpenoid EKO activates deubiqutinase ATXN3 to preserve vascular endothelial integrity and alleviate diabetic retinopathy through c-fos/focal adhesion axis

Diabetic retinopathy (DR) is one of the most prevalent severe diabetic microvascular complications caused by hyperglycemia. Deciphering the underlying mechanism of vascular injury and finding ways to alleviate hyperglycemia induced microvascular complications is of great necessity. In this study, we identified that a compound ent-9α-hydroxy-15-oxo-16-kauren-19-oic acid (EKO), the diterpenoid isolated and purified from Pteris semipinnata L., exhibited good protective roles against vascular endothelial injury associated with diabetic retinopathy in vitro and in vivo. To further uncover the underlying mechanism, we used unbiased transcriptome sequencing analysis and showed substantial impairment in the focal adhesion pathway upon high glucose and IL-1β stimulation. EKO could effectively improve endothelial focal adhesion pathway by enhancing the expression of two focal adhesion proteins Vinculin and ITGA11. We found that c-fos protein was involved in regulating the expression of Vinculin and ITGA11, a transcription factor component that was downregulated by high glucose and IL-1β stimulation and recovered by EKO. Mechanically, EKO facilitated the binding of deubiquitylation enzyme ATXN3 to c-fos protein and promoted its deubiquitylation, thereby elevating its protein level to enhance the expression of Vinculin and ITGA11. Besides, EKO effectively suppressed ROS production and restored mitochondrial function. In vivo studies, we confirmed EKO could alleviate some of the indicators of diabetic mice. In addition, protein levels of ATXN3 and focal adhesion Vinculin molecule were also verified in vivo. Collectively, our findings addressed the endothelial protective role of natural diterpenoid EKO, with emphasize of mechanism on ATXN3/c-fos/focal adhesion signaling pathway as well as oxygen stress suppression, implicating its therapeutic potential in alleviating vascular endothelium injury and diabetic retinopathy.

Genetic analysis of potential biomarkers and therapeutic targets in neuroinflammation from sporadic Creutzfeldt-Jakob disease

This study aimed to identify hub genes and pathological mechanisms related to neuroinflammation in Sporadic Creutzfeldt-Jakob disease (SCJD) based on comprehensive bioinformatics. SCJD and normal samples were collected from GSE160208. Weighted gene co-expression network analysis (WGCNA) and Limma R package were used to obtain key genes, which were used for enrichment and immune cell infiltration analyses. Protein-protein interaction (PPI) network, cytoHubba, and machine learning were used to screen the central genes of SCJD. The chemicals related to hub genes were predicted and explored by molecular docking. 88 candidate genes were screened. Enrichment analysis showed they were mainly related to bacterial and viral infection and immune cell activation. Immune cell infiltration analysis suggested that immune cell activation and altered activity of the immune system are involved in the progression of SCJD. After identifying hub genes, KIT and SPP1 had higher diagnostic efficacy for SCJD (AUC > 0.9), so they were identified as central genes. The molecular docking results showed hub genes both docked well with Tretinoin. KIT, SPP1, and Tretinoin are essential in developing neuroinflammation in SCJD and may provide new ideas for diagnosing and treating SCJD.

Peripheral Inflammation Links with the Severity of Clinical Phenotype in Spinocerebellar Ataxia 2

BACKGROUND

The role of peripheral inflammation in spinocerebellar ataxia type 2 (SCA2) is unknown.

OBJECTIVE

The objective of this study was to identify peripheral inflammation biomarkers and their relationship with the clinical and molecular features.

METHODS

Blood cell count-derived inflammatory indices were measured in 39 SCA2 subjects and their matched controls. Clinical scores of ataxia, nonataxia, and cognitive dysfunction were assessed.

RESULTS

The neutrophil-to-lymphocyte ratio (NLR), the platelet-to-lymphocyte ratio (PLR), the Systemic Inflammation Index (SII), and the Aggregate Index of Systemic Inflammation (AISI) were significantly increased in SCA2 subjects compared with controls. The increases in PLR, SII, and AISI were even observed in preclinical carriers. NLR, PLR, and SII were correlated with the Scale for the Assessment and Rating of Ataxia speech item score rather than with the total score. The NLR and SII were correlated with the nonataxia and the cognitive scores.

CONCLUSIONS

Peripheral inflammatory indices are biomarkers in SCA2, which may help to design future immunomodulatory trials and advance our understanding of the disease. © 2023 International Parkinson and Movement Disorder Society.

CBP-Mediated Acetylation of Importin α Mediates Calcium-Dependent Nucleocytoplasmic Transport of Selective Proteins in Drosophila Neurons

For proper function of proteins, their subcellular localization needs to be monitored and regulated in response to the changes in cellular demands. In this regard, dysregulation in the nucleocytoplasmic transport (NCT) of proteins is closely associated with the pathogenesis of various neurodegenerative diseases. However, it remains unclear whether there exists an intrinsic regulatory pathway(s) that controls NCT of proteins either in a commonly shared manner or in a target-selectively different manner. To dissect between these possibilities, in the current study, we investigated the molecular mechanism regulating NCT of truncated ataxin-3 (ATXN3) proteins of which genetic mutation leads to a type of polyglutamine (polyQ) diseases, in comparison with that of TDP-43. In Drosophila dendritic arborization (da) neurons, we observed dynamic changes in the subcellular localization of truncated ATXN3 proteins between the nucleus and the cytosol during development. Moreover, ectopic neuronal toxicity was induced by truncated ATXN3 proteins upon their nuclear accumulation. Consistent with a previous study showing intracellular calcium-dependent NCT of TDP-43, NCT of ATXN3 was also regulated by intracellular calcium level and involves Importin α3 (Imp α3). Interestingly, NCT of ATXN3, but not TDP-43, was primarily mediated by CBP. We further showed that acetyltransferase activity of CBP is important for NCT of ATXN3, which may acetylate Imp α3 to regulate NCT of ATXN3. These findings demonstrate that CBP-dependent acetylation of Imp α3 is crucial for intracellular calcium-dependent NCT of ATXN3 proteins, different from that of TDP-43, in Drosophila neurons.