Analysis of Potential Biomarkers in Frontal Temporal Dementia: A Bioinformatics Approach.

Frontal temporal dementia (FTD) is a neurological disorder known to have fewer therapeutic options. So far, only a few biomarkers are available for FTD that can be used as potential comorbidity targets. For example, genes such as VCP, which has a role in breast cancer, and WFS1, which has a role in COVID-19, are known to show a role in FTD as well. To this end, in the present study, we aim to identify potential biomarkers or susceptible genes for FTD that show comorbidities with diseases such as COVID-19 and breast cancer. A dataset from Gene Expression Omnibus containing FTD expression profiles from African American and white ethnicity backgrounds was included in our study. In FTD samples of the GSE193391 dataset, we identified 305 DEGs, with 168 genes being up-regulated and 137 genes being down-regulated. We conducted a comorbidity analysis for COVID-19 and breast cancer, followed by an analysis of potential drug interactions, pathogenicity, analysis of genetic variants, and functional enrichment analysis. Our results showed that the genes AKT3, GFAP, ADCYAP1R1, VDAC1, and C4A have significant transcriptomic alterations in FTD along with the comorbidity status with COVID-19 and breast cancer. Functional pathway analysis revealed that these comorbid genes were significantly enriched in the pathways such as glioma, JAK/STAT signaling, systematic lupus erythematosus, neurodegeneration-multiple diseases, and neuroactive ligand-receptor interaction. Overall, from these results, we concluded that these genes could be recommended as potential therapeutic targets for the treatment of comorbidities (breast cancer and COVID-19) in patients with FTD.

Quantified Brain Magnetic Resonance Imaging Volumes Differentiate Behavioral Variant Frontotemporal Dementia from Early-Onset Alzheimer's Disease.

BACKGROUND: The differentiation of behavioral variant frontotemporal dementia (bvFTD) from early-onset Alzheimer's disease (EOAD) by clinical criteria can be inaccurate. The volumetric quantification of clinically available magnetic resonance (MR) brain scans may facilitate early diagnosis of these neurodegenerative dementias. OBJECTIVE: To determine if volumetric quantification of brain MR imaging can identify persons with bvFTD from EOAD. METHODS: 3D T1 MR brain scans of 20 persons with bvFTD and 45 with EOAD were compared using Neuroreader to measure subcortical, and lobar volumes, and Volbrain for hippocampal subfields. Analyses included: 1) discriminant analysis with leave one out cross-validation; 2) input of predicted probabilities from this process into a receiver operator characteristic (ROC) analysis; and 3) Automated linear regression to identify predictive regions. RESULTS: Both groups were comparable in age and sex with no statistically significant differences in symptom duration. bvFTD had lower volume percentiles in frontal lobes, thalamus, and putamen. EOAD had lower parietal lobe volumes. ROC analyses showed 99.3% accuracy with Neuroreader percentiles and 80.2% with subfields. The parietal lobe was the most predictive percentile. Although there were differences in hippocampal (particularly left CA2-CA3) subfields, it did not add to the discriminant analysis. CONCLUSION: Percentiles from an MR based volumetric quantification can help differentiate between bvFTD from EOAD in routine clinical care. Use of hippocampal subfield volumes does not enhance the diagnostic separation of these two early-onset dementias.

Tau Modulates mRNA Transcription, Alternative Polyadenylation Profiles of hnRNPs, Chromatin Remodeling and Spliceosome Complexes.

Tau protein is a known contributor in several neurodegenerative diseases, including Alzheimer's disease (AD) and frontotemporal dementia (FTD). It is well-established that tau forms pathological aggregates and fibrils in these diseases. Tau has been observed within the nuclei of neurons, but there is a gap in understanding regarding the mechanism by which tau modulates transcription. We are interested in the P301L mutation of tau, which has been associated with FTD and increased tau aggregation. Our study utilized tau-inducible HEK (iHEK) cells to reveal that WT and P301L tau distinctively alter the transcription and alternative polyadenylation (APA) profiles of numerous nuclear precursors mRNAs, which then translate to form proteins involved in chromatin remodeling and splicing. We isolated total mRNA before and after over-expressing tau and then performed Poly(A)-ClickSeq (PAC-Seq) to characterize mRNA expression and APA profiles. We characterized changes in Gene Ontology (GO) pathways using EnrichR and Gene Set Enrichment Analysis (GSEA). We observed that P301L tau up-regulates genes associated with reactive oxygen species responsiveness as well as genes involved in dendrite, microtubule, and nuclear body/speckle formation. The number of genes regulated by WT tau is greater than the mutant form, which indicates that the P301L mutation causes loss-of-function at the transcriptional level. WT tau up-regulates genes contributing to cytoskeleton-dependent intracellular transport, microglial activation, microtubule and nuclear chromatin organization, formation of nuclear bodies and speckles. Interestingly, both WT and P301L tau commonly down-regulate genes responsible for ubiquitin-proteosome system. In addition, WT tau significantly down-regulates several genes implicated in chromatin remodeling and nucleosome organization. Although there are limitations inherent to the model systems used, this study will improve understanding regarding the nuclear impact of tau at the transcriptional and post-transcriptional level. This study also illustrates the potential impact of P301L tau on the human brain genome during early phases of pathogenesis.

Specific support needs and experiences of carers of people with frontotemporal dementia: A systematic review.

INTRODUCTION: Frontotemporal dementia (FTD) is one of the most common types of dementia in persons younger than 65 years of age. Diagnosis is often delayed due to slow, gradual decline and misinterpretation of 'non-typical' dementia symptoms. Informal carers of people with FTD experience greater levels of overall burden than carers of people with other forms of dementia. The aim of this systematic review was to describe the subjective experience of being an informal carer of a person with FTD and to identify the specific needs, coping strategies and helpful support resources of this carer population. METHODS: Four electronic databases were used to search for published literature presenting experiences of carers of people with FTD between January 2003 and July 2019. Search strategy followed PRISMA guidelines. Findings were analysed using framework analysis, employing five stages of analysis to develop a coding index and thematic framework that included key aspects of the carer experience, which were grouped into themes and presented in a narrative format. RESULTS: 1213 articles were identified in total. Twelve studies were included in the final synthesis of the review. Six themes were identified: 'Challenging road to and receipt of diagnosis', 'relationship change and loss', 'challenging experiences in caring', 'positive experiences and resilience', 'coping' and 'support needs'. DISCUSSION: Findings highlight an increased need for carers of people with FTD to receive support during the pre-diagnostic stage, including support to manage symptoms. Further research should explore relationship changes and loss amongst carers to inform approaches for carer support. In conclusion, the lack of knowledge and unique needs of carers highlight the importance of public awareness campaigns and healthcare professional education to support carers with FTD symptom impact.

Regulation of nonsense-mediated mRNA decay in neural development and disease.

Eukaryotes have evolved a variety of mRNA surveillance mechanisms to detect and degrade aberrant mRNAs with potential deleterious outcomes. Among them, nonsense-mediated mRNA decay (NMD) functions not only as a quality control mechanism targeting aberrant mRNAs containing a premature termination codon but also as a posttranscriptional gene regulation mechanism targeting numerous physiological mRNAs. Despite its well-characterized molecular basis, the regulatory scope and biological functions of NMD at an organismal level are incompletely understood. In humans, mutations in genes encoding core NMD factors cause specific developmental and neurological syndromes, suggesting a critical role of NMD in the central nervous system. Here, we review the accumulating biochemical and genetic evidence on the developmental regulation and physiological functions of NMD as well as an emerging role of NMD dysregulation in neurodegenerative diseases.

Changes to the TDP-43 and FUS Interactomes Induced by DNA Damage.

The RNA-binding proteins TDP-43 and FUS are tied as the third leading known genetic cause for amyotrophic lateral sclerosis (ALS), and TDP-43 proteopathies are found in nearly all ALS patients. Both the natural function and contribution to pathology for TDP-43 remain unclear. The intersection of functions between TDP-43 and FUS can focus attention for those natural functions mostly likely to be relevant to disease. Here, we compare the role played by TDP-43 and FUS, maintaining chromatin stability for dividing HEK293T cells. We also determine and compare the interactomes of TDP-43 and FUS, quantitating changes in those before and after DNA damage. Finally, selected interactions with known importance to DNA damage repair were validated by co-immunoprecipitation assays. This study uncovered TDP-43 and FUS binding to several factors important to DNA repair mechanisms that can be replication-dependent, -independent, or both. These results provide further evidence that TDP-43 has an important role in DNA stability and provide new ways that TDP-43 can bind to the machinery that guards DNA integrity in cells.