Nanostring gene expression profiling for markers of Alzheimer's disease in MAPT P301S;cTFEB;HSACre and MAPT P301S male and female mice
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ABSTRACT: To assess the potential neuroprotective effects of overexpressing skeletal muscle Transcription Factor EB (TFEB) signaling in the context of age-associated neurodegenerative disease pathologies, we derived cTFEB;HSACre transgenic mice in the MAPT P301S tau hyperphosphorylated background and used the Nanostring nCounter® Alzheimer’s Disease panel to gain more precise insights into disease-relevant transcriptional changes in the hippocampus in both male and female mice with both Tau hyperphosphorylation and skeletal muscle TFEB overexpression. We confirmed significantly reduced transcriptional activation of the nCounter AD microglial activation module through signature scoring.
Project description:Skeletal muscle has recently arisen as a novel regulator of Central Nervous System (CNS) function and aging, secreting bioactive molecules known as myokines with metabolism-modifying functions in targeted tissues, including the CNS. Here we report the generation of a novel transgenic mouse with enhanced skeletal muscle lysosomal and mitochondrial function via targeted overexpression of Transcription Factor E-B (TFEB). We have discovered that the resulting geroprotective benefits in skeletal muscle reduces neuroinflammation and accumulation of tau-associated pathological hallmarks in a mouse model of tau pathology. Muscle TFEB overexpression also significantly ameliorates proteotoxicity, reduces neuroinflammation and promotes transcriptional remodeling of the aging CNS, preserving cognition and memory in aging mice. Our results implicate the maintenance of skeletal muscle function throughout aging to direct regulation of CNS health and disease, and suggest that skeletal-muscle originating factors may act as novel therapeutic targets against age-associated neurodegenerative disorders.
Project description:The development of an effective therapy against tauopathies like Alzheimer’s disease (AD) and frontotemporal dementia (FTD) remains challenging, partly due to limited access to fresh brain tissue, the lack of translational in vitro disease models and the fact that underlying molecular pathways remain to be deciphered. Several genes play an important role in the pathogenesis of AD and FTD, one of them being the MAPT gene encoding the microtubule-associated protein tau. Over the past few years, it has been shown that induced pluripotent stem cells (iPSC) can be used to model various human disorders and can serve as translational in vitro tools. Therefore, we generated iPSC harboring the pathogenic FTDP-17 (frontotemporal dementia and parkinsonism linked to chromosome 17) associated mutations IVS10+16 with and without P301S in MAPT using Zinc Finger Nuclease technology. Whole transcriptome analysis of MAPT IVS10+16 neurons reveals neuronal subtype differences, reduced neural progenitor proliferation potential and aberrant WNT signaling. Notably, all phenotypes were recapitulated using patient-derived neurons. Finally, an additional P301S mutation causes an increased calcium bursting frequency, reduced lysosomal acidity and tau oligomerization. Altogether, these tau mutant iPSC lines allow us to study IVS10+16 and P301S mutations in an isogenic background and to unravel a potential link between pathogenic 4R tau expression and FTDP-17.
Project description:Post-mortem investigations indicate that the locus coeruleus (LC) is the initial site of hyperphosphorylated pretangle tau, a precursor to neurofibrillary tangles (NFTs) found in Alzheimer's disease (AD). The presence of pretangle tau and NFTs in the LC correlates with AD progression. LC neuron integrity and quantity are linked to cognitive states, with degeneration associated with AD. However, the mechanisms of pretangle tau-induced LC degeneration are unclear. This study examined the transcriptomic and mitochondrial profiles of LC noradrenergic neurons after transduction with pseudophosphorylated human tau. Tau hyperphosphorylation increased the somatic expression of the L-type calcium channel (LTCC), impaired mitochondria health, and led to deficits in spatial and olfactory learning. Sex-dependent alterations in gene expression were observed in rats transduced with pretangle tau. Chronic LTCC blockade prevented behavioral deficits and altered mitochondrial mRNA expression, suggesting a potential link between LTCC hyperactivity and mitochondrial dysfunction. Our research provides insights into the consequences of tau pathology in the originating structure of AD.
Project description:One of the defining pathological features of Alzheimer’s Disease (AD) is the deposition of neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau in the brain. Aberrant activation of kinases in AD has been suggested to enhance phosphorylation and toxicity of tau, making the responsible tau kinases attractive therapeutic targets. The full complement of tau interacting kinases in AD brain and their activity in disease remains incompletely defined. Here, immunoaffinity enrichment coupled with mass spectrometry (MS) identified TANK-binding kinase 1 (TBK1) as a tau-interacting partner in human AD cortical brain tissues. We validated this interaction in human AD, familial frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17) caused by mutations in MAPT (R406W & P301L) and corticobasal degeneration (CBD) postmortem brain tissues as well as human cell lines. Further, we document increased TBK1 activation in both AD and FTDP-17 and map TBK1 phosphorylation sites on tau based on in vitro kinase assays coupled to MS. Lastly, in a Drosophila tauopathy model, activating expression of a conserved TBK1 ortholog triggers tau hyperphosphorylation and enhanced neurodegeneration, whereas knockdown had the reciprocal effect, suppressing tau toxicity. Collectively, our findings suggest that increased TBK1 activation may promote tau hyperphosphorylation and neuronal loss in AD and related tauopathies.
Project description:Tau is a microtubule-associated protein (MAPT, tau) implicated in the pathogenesis of Tauopathies, a spectrum of neurodegenerative disorders characterized by accumulation of hyperphosphorylated, aggregated tau. Because tau pathology can be distinct across diseases, a pragmatic therapeutic approach may be to intervene at the level of the tau transcript, as it makes no assumptions to mechanisms of tau toxicity. Here we performed a large library screen of locked-nucleic acid-modified antisense oligonucleotides (LNA-ASOs), where careful tiling of the MAPT locus resulted in the identification of hot spots for activity in the 3’UTR. Further modifications to the LNA design resulted in the generation of ASO-001933, which selectively and potently reduces tau in primary cultures from hTau mice, monkey, and human neurons. ASO-001933 was well-tolerated and produced a robust, long lasting reduction in tau protein in both mouse and cynomolgus monkey brain. In monkey, tau protein reduction was maintained in brain for 20 weeks post-injection and corresponded with tau protein reduction in the CSF. Our results demonstrate that LNA-ASOs exhibit excellent drug-like properties and sustained efficacy likely translating to infrequent, intrathecal dosing in patients. These data further support the development of LNA-ASOs against tau for the treatment of tauopathies.
Project description:Tau is a microtubule-associated protein (MAPT, tau) implicated in the pathogenesis of Tauopathies, a spectrum of neurodegenerative disorders characterized by accumulation of hyperphosphorylated, aggregated tau. Because tau pathology can be distinct across diseases, a pragmatic therapeutic approach may be to intervene at the level of the tau transcript, as it makes no assumptions to mechanisms of tau toxicity. Here we performed a large library screen of locked-nucleic acid-modified antisense oligonucleotides (LNA-ASOs), where careful tiling of the MAPT locus resulted in the identification of hot spots for activity in the 3’UTR. Further modifications to the LNA design resulted in the generation of ASO-001933, which selectively and potently reduces tau in primary cultures from hTau mice, monkey, and human neurons. ASO-001933 was well-tolerated and produced a robust, long lasting reduction in tau protein in both mouse and cynomolgus monkey brain. In monkey, tau protein reduction was maintained in brain for 20 weeks post-injection and corresponded with tau protein reduction in the CSF. Our results demonstrate that LNA-ASOs exhibit excellent drug-like properties and sustained efficacy likely translating to infrequent, intrathecal dosing in patients. These data further support the development of LNA-ASOs against tau for the treatment of tauopathies.
Project description:Tau is a microtubule-associated protein (MAPT, tau) implicated in the pathogenesis of Tauopathies, a spectrum of neurodegenerative disorders characterized by accumulation of hyperphosphorylated, aggregated tau. Because tau pathology can be distinct across diseases, a pragmatic therapeutic approach may be to intervene at the level of the tau transcript, as it makes no assumptions to mechanisms of tau toxicity. Here we performed a large library screen of locked-nucleic acid-modified antisense oligonucleotides (LNA-ASOs), where careful tiling of the MAPT locus resulted in the identification of hot spots for activity in the 3’UTR. Further modifications to the LNA design resulted in the generation of ASO-001933, which selectively and potently reduces tau in primary cultures from hTau mice, monkey, and human neurons. ASO-001933 was well-tolerated and produced a robust, long lasting reduction in tau protein in both mouse and cynomolgus monkey brain. In monkey, tau protein reduction was maintained in brain for 20 weeks post-injection and corresponded with tau protein reduction in the CSF. Our results demonstrate that LNA-ASOs exhibit excellent drug-like properties and sustained efficacy likely translating to infrequent, intrathecal dosing in patients. These data further support the development of LNA-ASOs against tau for the treatment of tauopathies.
Project description:Neuroinflammation is one of the major neuropathological hallmarks of Alzheimer's disease (AD) and related tauopathies. Activated microglia often co-exist in the same brain regions where tau protein accumulates as hyperphosphorylated and aggregated PHFs or neurofibrillary tangles (NFTs) within neurons in patients with AD and related tauopathies. However, the exact mechanisms how pathological tau could induce neuroinflammatory responses are not clear. In this study, we treated primary human microglia with purified human PHFs and performed RNA-sequence analysis.
Project description:Frontotemporal dementia (FTD) is an incurable group of early-onset dementias that can be caused by deposition of hyperphosphorylated tau in patient brains. However, the mechanisms leading to neurodegeneration remain largely unknown. Here, we combined single-cell analyses of FTD patient brains with a stem cell culture and transplantation model of FTD. We identified disease phenotypes in FTD neurons carrying the MAPT-N279K mutation, which were related to oxidative stress, oxidative phosphorylation and neuroinflammation with an upregulation of the inflammation-associated protein osteopontin (OPN). Human FTD neurons survived less and elicited an increased microglial response after transplantation into the mouse forebrain, that we further characterized by single nucleus RNA-sequencing of microdissected grafts. Notably, downregulation of OPN in engrafted FTD neurons resulted in improved engraftment and reduced microglial infiltration, indicating an immune-modulatory role of OPN in patient neurons, which may represent a potential therapeutic target in FTD.
Project description:Frontotemporal dementia (FTD) is an incurable group of early-onset dementias that can be caused by deposition of hyperphosphorylated tau in patient brains. However, the mechanisms leading to neurodegeneration remain largely unknown. Here, we combined single-cell analyses of FTD patient brains with a stem cell culture and transplantation model of FTD. We identified disease phenotypes in FTD neurons carrying the MAPT-N279K mutation, which were related to oxidative stress, oxidative phosphorylation and neuroinflammation with an upregulation of the inflammation-associated protein osteopontin (OPN). Human FTD neurons survived less and elicited an increased microglial response after transplantation into the mouse forebrain, that we further characterized by single nucleus RNA-sequencing of microdissected grafts. Notably, downregulation of OPN in engrafted FTD neurons resulted in improved engraftment and reduced microglial infiltration, indicating an immune-modulatory role of OPN in patient neurons, which may represent a potential therapeutic target in FTD.