Project description:No treatment for frontotemporal dementia (FTD), the second most common type of early-onset dementia, is available, but therapeutics are being investigated to target the 2 main proteins associated with FTD pathological subtypes: TDP-43 (FTLD-TDP) and tau (FTLD-tau). Testing potential therapies in clinical trials is hampered by our inability to distinguish between patients with FTLD-TDP and FTLD-tau. Therefore, we evaluated truncated stathmin-2 (STMN2) as a proxy of TDP-43 pathology, given the reports that TDP-43 dysfunction causes truncated STMN2 accumulation. Truncated STMN2 accumulated in human induced pluripotent stem cell–derived neurons depleted of TDP-43, but not in those with pathogenic TARDBP mutations in the absence of TDP-43 aggregation or loss of nuclear protein. In RNA-Seq analyses of human brain samples from the NYGC ALS cohort, truncated STMN2 RNA was confined to tissues and disease subtypes marked by TDP-43 inclusions. Last, we validated that truncated STMN2 RNA was elevated in the frontal cortex of a cohort of patients with FTLD-TDP but not in controls or patients with progressive supranuclear palsy, a type of FTLD-tau. Further, in patients with FTLD-TDP, we observed significant associations of truncated STMN2 RNA with phosphorylated TDP-43 levels and an earlier age of disease onset. Overall, our data uncovered truncated STMN2 as a marker for TDP-43 dysfunction in FTD.
Project description:Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are associated with loss of nuclear TDP-43. Here we identify that TDP-43 regulates expression of the neuronal growth-associated factor stathmin-2. Lowered TDP-43 levels, which reduce its binding to sites within the first intron of stathmin-2 pre-mRNA, uncover a cryptic polyadenylation site whose utilization produces a truncated, non-functional mRNA. Reduced stathmin-2 expression is found in neurons trans-differentiated from patient fibroblasts expressing an ALS-causing TDP-43 mutation, in motor cortex and spinal motor neurons from sporadic ALS patients and familial ALS patients with expansion in C9orf72, and in induced pluripotent stem cell (iPSC)-derived motor neurons depleted of TDP-43. Remarkably, while reduction in TDP-43 is shown to inhibit axonal regeneration of iPSC-derived motor neurons, rescue of stathmin-2 expression restores axonal regenerative capacity. Thus, premature polyadenylation-mediated reduction in stathmin-2 is a hallmark of ALS/FTD that functionally links reduced nuclear TDP-43 function to enhanced neuronal vulnerability.
Project description:We have performed methylation microarray analysis of two types of dementia, Alzheimer's disease (AD) and frontotemporal dementia (FTD), using two kind of samples, frozen brain tissue and lymphoblastoid cell lines.
Project description:Alzheimer’s disease (AD) and Frontotemporal dementia (FTD) are the two most common forms of dementia that occur during aging. Both AD and FTD are associated with the pathological aggregation of proteins. Nevertheless, it remains unclear how these protein aggregates lead to neuronal cell death in these dementias. Here we show that the histone demethylase LSD1 is mislocalized with cytoplasmic aggregates in human cases of AD and FTD. In addition, loss of LSD1 systemically in adult mice is sufficient to recapitulate many aspects of these diseases. From these data, we propose that the aggregation of Tau and TDP-43 lead to neuronal cell death in AD and FTD by interfering with the continuous requirement for LSD1 to repress inappropriate transcription. Furthermore, we observe the inappropriate reactivation of stem cell loci in the hippocampal neurons of LSD1 mutant mice. This suggests that LSD1 may function to maintain the fate of differentiated neurons by repressing stem cell transcription.
Project description:Understanding the molecular mechanisms underlying frontotemporal dementia (FTD) is essential for the development of successful therapies. Systematic studies on human post-mortem brain tissue of patients with genetic subtypes of FTD are currently lacking. The Risk and Modyfing Factors of Frontotemporal Dementia (RiMod-FTD) consortium therefore has generated multi-omics datasets for genetic subtypes of FTD to identify common and distinct molecular mechanisms disturbed in disease. This experiment contains data from smRNA-sequencing of human post-mortem brain tissue of the frontal lobe from patients with FTD caused by mutations in GRN, MAPT or C9orf72 and healthy controls.
Project description:In order to obtain an overview of gene expression changes in CHMP2B-dependent frontotemporal dementia (FTD3), RNA sequencing analyses were performed in FTD3 patient neurons compared to their gene-corrected isogenic controls.
Project description:Methylation state of human post-mortem brain tissue from the frontal lobe of patients with Frontotemporal Dementia caused by mutations in GRN, MAPT and C9orf72 and healthy controls