Expression Of Microtubule-associated Protein Tau Research Articles

Characterization and expression of the microtubule associated protein tau gene isoforms and their impact on clinical outcomes in glioma patients

Gliomas are the most common tumors found in the central nervous system. They are classified based on their histopathological malignancy. Low-grade gliomas (LGG) can turn into glioblastomas (GBM), the most aggressive form of brain cancer with the worst prognosis. Previous studies have shown that microtubule-associated protein tau (MAPT) is increased in GBM and that reducing it can improve survival in animal models. On the other hand, elevated MAPT expression has been linked to increased survival in LGG, indicating its potential as a survival biomarker. However, previous studies have primarily focused on the canonical protein-coding transcripts and gene-level expression of MAPT, disregarding the diversity of its many isoforms. Many diseases in almost every tissue have been associated with a dysregulation of alternative splicing, either through an altered ratio of the expressed isoforms or by expressing aberrant transcripts with different alternative transcription start and termination sites. This study investigates the association of specific MAPT transcripts with survival in LGG and GBM using publicly available genomic datasets and performing statistical analyses. The results of the study indicated coding and several non-coding isoforms associated with overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI). After including the relevant predictors as covariates, it was observed that among the protein-coding isoforms, MAPT-205 and MAPT-201 were significantly associated with clinical survival endpoints, but with opposite trends. These findings highlight the importance of studying the role of MAPT isoforms in glioma cellular phenotypes, aggressiveness, and patient survival.

Alzheimer’s disease phenotypes in human induced pluripotent stem cell‐based models of Down syndrome

AbstractBackgroundBy age 40, all people with Down syndrome (DS) develop Alzheimer’s disease (AD) brain neuropathology, including Aβ plaques and neurofibrillary tangles of phosphorylated microtubule associated protein tau (MAPT), and most go on to develop early‐onset dementia. People with Down syndrome (DS) have triplication of chromosome 21 (trisomy 21) and they develop AD neuropathology due to triplication of the amyloid precursor protein gene (APP) which resides on chromosome 21. Here, we developed and characterized human induced pluripotent stem cell (hiPSC)‐derived neurons, astrocytes, microglia, and cerebral organoid (CO) models of DS and familial AD and used them to evaluate the AD‐related pathological mechanisms caused by trisomy 21.MethodWe obtained hiPSC lines derived from individuals with DS, healthy control individuals (HC), and individuals with familial AD, including duplication of APP on one chromosome (APPdup) or carrying the London mutation in APP (APPV717I). All donors had the apolipoprotein E (APOE) ε3/ε3 genotype. We generated hiPSC‐derived neurons, astrocytes, microglia, and COs using validated techniques. We evaluated the hiPSC‐derived neural cells and COs at different ages for AD‐related neuropathology, neuroinflammation, and neurodegeneration by performing RNA sequencing, immunohistochemistry, immunoblotting, and enzyme‐linked immunosorbent assay.ResultAD‐related size phenotypes characteristic of neurodegeneration were observed in DS hiPSC‐based models relative to HC models. Dysregulated gene and protein expression of APP, MAPT, and APOE, in addition to chromosome 21 genes, were also observed in DS hiPSC‐based models. In particular, neuroinflammatory markers, especially those previously shown in APOE‐related pathways, were also increased in DS models.ConclusionWe characterized new hiPSC‐based models of DS and familial AD which will be useful for identifying commonalities in disease mechanisms as well as for dissecting the roles of chromosome 21 genes other than APP. We identified several AD‐related phenotypes in hiPSC‐based DS related to neuropathology, neuroinflammation, and neurodegeneration. We expect that these hiPSC‐based models will be useful for testing therapeutics in the future to address AD in people with DS, for which there is no cure.

Cell-specific MAPT gene expression is preserved in neuronal and glial tau cytopathologies in progressive supranuclear palsy

Microtubule-associated protein tau (MAPT) aggregates in neurons, astrocytes and oligodendrocytes in a number of neurodegenerative diseases, including progressive supranuclear palsy (PSP). Tau is a target of therapy and the strategy includes either the elimination of pathological tau aggregates or reducing MAPT expression, and thus the amount of tau protein made to prevent its aggregation. Disease-associated tau affects brain regions in a sequential manner that includes cell-to-cell spreading. Involvement of glial cells that show tau aggregates is interpreted as glial cells taking up misfolded tau assuming that glial cells do not express enough MAPT. Although studies have evaluated MAPT expression in human brain tissue homogenates, it is not clear whether MAPT expression is compromised in cells accumulating pathological tau. To address these perplexing aspects of disease pathogenesis, this study used RNAscope combined with immunofluorescence (AT8), and single-nuclear(sn) RNAseq to systematically map and quantify MAPT expression dynamics across different cell types and brain regions in controls (n = 3) and evaluated whether tau cytopathology affects MAPT expression in PSP (n = 3). MAPT transcripts were detected in neurons, astrocytes and oligodendrocytes, and varied between brain regions and within each cell type, and were preserved in all cell types with tau aggregates in PSP. These results propose a complex scenario in all cell types, where, in addition to the ingested misfolded tau, the preserved cellular MAPT expression provides a pool for local protein production that can (1) be phosphorylated and aggregated, or (2) feed the seeding of ingested misfolded tau by providing physiological tau, both accentuating the pathological process. Since tau cytopathology does not compromise MAPT gene expression in PSP, a complete loss of tau protein expression as an early pathogenic component is less likely. These observations provide rationale for a dual approach to therapy by decreasing cellular MAPT expression and targeting removal of misfolded tau.

WVE‐005, a stereopure antisense oligonucleotide for MAPT silencing in tauopathies

Abstract Background: Tau is a neuronal scaffolding protein which aggregates intracellularly upon hyperphosphorylation to form neurofibrillary tangles (NFT). NFTs are a hallmark of various microtubule associated protein tau (MAPT)‐associated neurodegenerative diseases, including Alzheimer’s disease, frontotemporal dementia, and progressive supranuclear palsy. Currently, there is no approved treatment targeting Tau pathology, nor any other disease‐modifying therapy for these diseases. Wave Life Sciences has developed a stereopure antisense oligonucleotide to reduce MAPT expression in patients with MAPT‐associated neurodegenerative diseases. Method: Using Wave’s proprietary PRISM platform, we designed and screened stereopure oligonucleotides targeting MAPT in vitro and identified a lead sequence. PN chemistry was applied to the lead sequence in subsequent studies to further improve pharmacological properties. In vitro target engagement was measured in human iCell neurons after treatment with Wave’s oligonucleotide, WVE‐005, or a published reference stereorandom oligonucleotide under gymnotic conditions. For in vivo analysis, transgenic mice received a single dose of 12.5, 25, 50, or 100µg oligonucleotide, and target engagement was measured after 4 weeks. To measure duration, transgenic mice received a single 100µg ICV dose and target engagement was tracked over 6 months. Finally, oligonucleotides were tested in non‐human primates (NHP) in a 12mg single‐dose intrathecal (IT) study. MAPT mRNA levels were quantified by qPCR, and intracellular distribution was evaluated by ViewRNA. Result: WVE‐005 showed dose‐dependent silencing of MAPT mRNA in iPSC‐derived neurons with an IC50 of 84nM. In a dose‐response study, 12.5µg and 25µg WVE‐005 led to 50% knockdown after 4 weeks in hippocampus and cortex, respectively, in transgenic mice. WVE‐005 led to >77% MAPT mRNA knockdown at 12 weeks post 100µg dosing, with knockdown of approximately 50% persisting 6 months post‐injection. In NHPs, WVE‐005 showed improved distribution and potency compared to non‐PN oligonucleotide with the same sequence. WVE‐005 decreased MAPT expression across NHP brain regions 28 days post‐single dose much greater than the non‐PN oligonucleotide and was detected in neuronal and glial cells. Conclusion: WVE‐005 potently and durably decreased MAPT mRNA expression in vitro and in multiple animal models, including throughout CNS upon IT administration in NHPs. These data support continued evaluation of WVE‐005 as a potential therapeutic for MAPT‐associated neurodegenerative diseases.

Targeting Microtubule-Associated Protein Tau in Chemotherapy-Resistant Models of High-Grade Serous Ovarian Carcinoma.

Simple SummaryResistance to chemotherapy in patients with high-grade serous ovarian carcinoma is a clinically relevant problem, and it results in high mortality. The aim of the study was to determine whether targeting microtubule-associated protein tau could reduce cell proliferation and tumor burden in cell culture and mouse models of chemotherapy-resistant high-grade serous ovarian carcinoma. To achieve this aim, I tested an inhibitor of tau, leucomethylene blue, which was originally developed against neurodegenerative diseases, and found that it efficiently reduced cell and tumor growth. Additionally, paclitaxel and leucomethylene blue synergized in reducing cell growth and tumor burden. Altogether, the data demonstrate that tau could be considered a new target for treatment of chemotherapy-resistant high-grade serous ovarian carcinoma, and leucomethylene blue could potentially add to the arsenal of drugs to treat the terminal stage of this deadly malignancy.Relapsed, recurrent, chemotherapy-resistant high-grade serous ovarian carcinoma is the deadliest stage of this disease. Expression of microtubule-associated protein tau (tau) has been linked to resistance to paclitaxel treatment. Here, I used models of platinum-resistant and created models of platinum/paclitaxel-resistant high-grade serous ovarian carcinoma to examine the impact of reducing tau expression on cell survival and tumor burden in cell culture and xenograft and syngeneic models of the disease. Tau was overexpressed in platinum/paclitaxel-resistant models; expression of phosphoSer396 and phosphoThr181 species was also found. A treatment with leucomethylene blue reduced the levels of tau in treated cells, was cytotoxic in cell cultures, and efficiently reduced the tumor burden in xenograft models. Furthermore, a combination of leucomethylene blue and paclitaxel synergized in eliminating cancer cells in cell culture and xenograft models. These findings underscore the feasibility of targeting tau as a treatment option in terminal-stage high-grade serous ovarian cancer.

MAPT enhancer containing rs242557 regulates multiple neighboring genes in human microglial cell line.

Microtubule associated protein tau (MAPT) is involved in assembly and stabilization of microtubules. However, mutated or misfolded forms are commonly found to aggregate in Frontotemporal dementia (FTD), Progressive supranuclear palsy (PSP), Corticobasal degeneration (CBD) etc. singly or with another protein as in Alzheimer's disease (AD). The second strongest signal in MAPT locus after H1 haplotype, as identified by multiple GWAS on AD, PD, PSP and CBD, is from MAPT intronic SNP rs242557. It is part of a FANTOM5 enhancer in eye and brain and evolutionarily conserved from humans to armadillo. While it has been hypothesized that rs242557 could exert an effect on MAPT splicing, the results are contradictory. Strong, Independent signals from MAPT neighboring genes KANSL1, NSF LRR37A and WNT3 have also been noted in some of these diseases. In this study we investigate the role of the enhancer region encompassing rs242557 in gene regulation within MAPT locus. Established CRISPR-Cas9 editing protocols were used to delete rs242557 and its flanking sequences in human microglial clone 3 (HMC3) and human neuroblastoma (NBL-S) cell lines. Heterozygous and homozygous clones with deleted rs242557 and its flanking sequences were individually selected for the study. Cells that went through the entire process of genome editing protocol without the presence of any guide RNA were used as wild type controls. cDNA, synthesized from extracted RNA were used to study expression of MAPT isoforms and its neighboring genes by qRT-PCR, while western blots were performed from the corresponding proteins. HMC-3 cells had significant reduction (p=0.0001) of Nsf, Kansl1, Kansl1-AS1, LRR37A, LRR37A2 and LRR37A3 transcripts in both rs242557 homozygous and heterozygous deletion clones. Total MAPT, MAPT isoforms (3R, 4R, 0N, 1N and 2N) and CRHR1 were also low with some having ct values beyond 33. At the protein level reduced expression of NSF and KANSL1 were noted in the homozygotes and some heterozygotes. No significant alteration was observed in the NBL-S clones. Experiments are currently in progress for the remaining neighboring proteins. Our results indicate that the enhancer encompassing rs242557 alters expression of MAPT and several of its neighbors in HMC-3 but not NBL-S cells.

A natural small molecule induces MAPT clearance via mTOR-independent autophagy

Autophagy, the process of lysosomal degradation of biological materials within cells, is often halted abnormally in proteopathies, such as tauopathy and amyloidopathy. Thus, autophagy regulators that rescue dysregulated autophagy have great potential to treat proteopathies. We previously reported that the natural small molecule kaempferide (Kaem) induces autophagy without perturbing mTOR signaling. Here, we report that Kaem promotes lysosomal degradation of microtubule-associated protein tau (MAPT) in inducible MAPT cells. Kaem enhanced autophagy flux by mitigating microtubule-associated protein 1 light chain 3 (LC3) accumulation when MAPT expression was induced. Kaem also promoted activation of transcription factor EB (TFEB) without inhibiting mTOR and without mTOR inhibition-mediated cytotoxicity. In addition, Kaem-induced MAPT degradation was abolished in the absence of mitochondrial elongation factor Tu (TUFM), which was previously shown to be a direct binding partner of Kaem. Collectively, these results demonstrate that Kaem could be a potential therapeutic for tauopathy and reveal that TUFM can be a drug target for autophagy-driven disorders.

Long non-coding RNA 00507/miRNA-181c-5p/TTBK1/MAPT axis regulates tau hyperphosphorylation in Alzheimer's disease.

Tau hyperphosphorylation is involved in the progression of Alzheimer's disease (AD). In the present study, we aimed to evaluate the role of linc00507 with respect to modulating Tau phosphorylation in ab AD animal and an Aβ42-SH-SY5Y cell model. Aβ precursor protein (APP)/PS transgenic mice and Aβ42-SH-SY5Y cell model were used to investigate the role of linc00507 in AD. A quantitative real-time polymerase chain reaction evaluated the RNA expression of linc00507, miR-181c-5p and microtubule-associated protein tau (MAPT)/tau-tubulin kinase-1 (TTBK1). The interactions between the genes were investigated through changes in one gene expression by regulating another gene in cells and, in addition, correlation assays were performed in mice. Western blot assays examined the protein expression of MAPT/TTBK1, phosphorylation of tau and signaling proteins P25/P35/GSK3β in response to the regulation of linc00507, miR-181c-5p and MAPT/TTBK1 in cells and also in mice. linc00507 was significantly elevated in hippocampus, and cerebral cortex of APP/PS transgenic mice and AD-like SH-SY5Y cells. It could bind miR-181c-5p and thereby regulate the expression of microtubule-associated protein Tau (MAPT) and tau-tubulin kinase-1 (TTBK1) as a competitive endogenous RNA (ceRNA). MAPT (encoding the tau protein) and TTBK1 (encoding a tau kinase) were identified as direct target genes of miR-181c-5p. Furthermore, linc00507 mediated tau protein hyperphosphorylation by the activation of the P25/P35/GSK3β signaling pathway through regulating MAPT/TTBK1 by sponging miR-181c-5p. The findings of the present highlight the regulatory role of linc00507 in tau phosphorylation miR-181c-5p as ceRNA of MAPT/TTBK1 in vitro and in vivo, providing a basis for novel diagnostic and treatment strategies for AD.

Nimodipine Improves Cognitive Impairment After Subarachnoid Hemorrhage in Rats Through IncRNA NEAT1/miR-27a/MAPT Axis.

BackgroundSubarachnoid hemorrhage (SAH) is a cerebral hemorrhage disease that severely damages the brain and causes cognitive impairment (CI). Therefore, accurate and appropriate treatment strategies are urgently needed. The application of nimodipine can not only improve blood circulation in patients with SAH but also repair ischemic neuron injury.PurposeTo investigate the effects of nimodipine and lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1)/miR-27a/microtubule-associated protein tau (MAPT) axis on CI after SAH.MethodsOne hundred and twenty healthy male rats were selected and equally divided into control group, sham operation group, model group, PBS group, nimodipine group (drug group), NC siRNA group, NC mimics group, NEAT1 siRNA, miR-27a mimics, MAPT siRNA, drug + NEAT1-ad, and drug + NC-ad groups by random number table. Rats in the model group were constructed by double-hemorrhage model, and expression vectors were injected into the tail to regulate the expression of lncRNA NEAT1, miR-27a and MAPT. In addition, Western blot was employed to detect brain tissue protein, flow cytometry was applied to measure brain tissue apoptosis, and MTT was utilized to determine cell activity, so as to evaluate brain damage and cognitive function in each group.ResultsNimodipine, down-regulated lncRNA NEAT1, up-regulated miR-27a and down-regulated MAPT all improved brain damage and CI, inhibited brain tissue cell apoptosis, and enhanced brain cell activity. The common binding sites of lncRNA NEAT1 and MAPT were found on the miR-27a sequence fragment, and miR-27a could be paired with the former two. Nimodipine was found to cause the down-regulation of lncRNA NEAT1 and MAPT, as well as the up-regulation of miR-27a.ConclusionNimodipine can improve CI after SAH in rats through the lncRNA NEAT1/miR-27a/MAPT axis.

Microtubule-associated protein tau (MAPT) promotes bicalutamide resistance and is associated with survival in prostate cancer

IntroductionMicrotubule-associated protein tau (MAPT), facilitates tubulin assembly and microtubule stabilization. Several studies have shown that overexpression of MAPT is linked to poor prognosis and is involved in taxane resistance in cancer. This study aimed to assess the expression and function of MAPT in prostate cancer (CaP). MethodsThe expression of MAPT was determined using immunohistochemistry in CaP. We analyzed the interaction between MAPT, Phosphatase and Tensin Homolog (PTEN), and androgen receptor and investigated the role of MAPT in bicalutamide resistance. ResultsImmunohistochemistry in 155 CaP cases showed that 15% of them were positive for MAPT. High MAPT expression was significantly orrelated with high Gleason score and high T stage. Kaplan-Meier analysis showed that the high MAPT expression was significantly associated with poor prostate-specific antigen recurrence survival after radical prostatectomy. There was an inverse correlation between MAPT and PTEN. In the CaP cell lines, knockout of PTEN increased the expression of MAPT, whereas knockdown of MAPT suppressed the expression of androgen receptor and increased the sensitivity to bicalutamide. Furthermore, immunohistochemical staining of MAPT showed that high MAPT expression was significantly associated with poor overall survival in 74 CaP patients who were treated with androgen deprivation therapy. ConclusionThese results suggest that MAPT may be a promising predictive biomarker for survival and play an essential role in bicalutamide resistance in CaP.

Microtubule-associated protein tau (MAPT) is a promising independent prognostic marker and tumor suppressive protein in clear cell renal cell carcinoma

IntroductionMicrotubule-associated protein tau (MAPT) overexpression has been linked to poor prognosis in several cancers. MAPT-AS1 is a long noncoding RNA existing at the antisense strand of the MAPT promoter region. The clinical significance of MAPT and MAPT-AS-1 in clear cell renal cell carcinoma (ccRCC) is unknown. This study aimed to assess the expression and function of MAPT and MAPT-AS1 in ccRCC. MethodsThe expression of MAPT was determined using immunohistochemistry in ccRCC. The effects of MAPT knockdown on cell growth and invasion were evaluated and the interaction between MAPT and microtubule-associated protein tau antisense (MAPT-AS1) were analyzed. The expression of MAPT-AS1 was determined using quantitative reverse transcription polymerase chain reaction in ccRCC tissues. We investigated the effect of MAPT-AS1 knockdown on cell growth and invasion. We analyzed the regulation of MAPT and MAPT-AS1. ResultsImmunohistochemistry in 135 ccRCC cases showed that 61% of the cases were positive for MAPT. Kaplan-Meier analysis showed that the low expression of MAPT was associated with poor overall survival after nephrectomy. Knockdown of MAPT enhanced cell growth and invasion. quantitative reverse transcription polymerase chain reaction revealed a positive correlation between MAPT and MAPT-AS1. The expression of MAPT-AS1 was higher in ccRCC tissue than in nonneoplastic kidney tissue. Kaplan-Meier analysis showed that the low expression of MAPT-AS1 was associated with poor overall survival after nephrectomy by in silico analysis. MAPT-AS1 knockdown promoted cell growth and invasion activity. P53 knockout suppressed the expression of MAPT and MAPT-AS1. ConclusionThese results suggest that MAPT and MAPT-AS1 may be promising predictive biomarkers for survival and play a tumor-suppressive role in ccRCC.

Overexpression of MAPT-AS1 is associated with better patient survival in breast cancer.

Breast cancer is the most frequent malignant disease in women worldwide. It is a heterogeneous and complex genetic disease with different molecular characteristics. MAPT-AS1, a long non-coding RNA (lncRNA) existing at the anti-sense strand of the MAPT (microtubule associated protein tau) promoter region, was believed to regulate MAPT, which was associated with disease state in Parkinson's disease. But the role of MAPT-AS1 in breast cancer has never been reported. In our study we found that MAPT-AS1 is overexpressed in breast cancer but not in triple negative breast cancer (TNBC), and that high expression of MAPT-AS1 was correlated with better patient survival. In addition, the level of MAPT-AS1 was correlated with the expression of MAPT, and MAPT was associated with survival time in breast cancer. Our study suggests that MAPT-AS1 may play a role and be a potential survival predictive biomarker in breast cancer.

MAPT Genetic Variation and Neuronal Maturity Alter Isoform Expression Affecting Axonal Transport in iPSC-Derived Dopamine Neurons.

SummaryThe H1 haplotype of the microtubule-associated protein tau (MAPT) locus is genetically associated with neurodegenerative diseases, including Parkinson's disease (PD), and affects gene expression and splicing. However, the functional impact on neurons of such expression differences has yet to be fully elucidated. Here, we employ extended maturation phases during differentiation of induced pluripotent stem cells (iPSCs) into mature dopaminergic neuronal cultures to obtain cultures expressing all six adult tau protein isoforms. After 6 months of maturation, levels of exon 3+ and exon 10+ transcripts approach those of adult brain. Mature dopaminergic neuronal cultures display haplotype differences in expression, with H1 expressing 22% higher levels of MAPT transcripts than H2 and H2 expressing 2-fold greater exon 3+ transcripts than H1. Furthermore, knocking down adult tau protein variants alters axonal transport velocities in mature iPSC-derived dopaminergic neuronal cultures. This work links haplotype-specific MAPT expression with a biologically functional outcome relevant for PD.

Wild-Type, but Not Mutant N296H, Human Tau Restores Aβ-Mediated Inhibition of LTP in Tau-/- mice.

Microtubule associated protein tau (MAPT) is involved in the pathogenesis of Alzheimer's disease and many forms of frontotemporal dementia (FTD). We recently reported that Aβ-mediated inhibition of hippocampal long-term potentiation (LTP) in mice requires tau. Here, we asked whether expression of human MAPT can restore Aβ-mediated inhibition on a mouse Tau−/− background and whether human tau with an FTD-causing mutation (N296H) can interfere with Aβ-mediated inhibition of LTP. We used transgenic mouse lines each expressing the full human MAPT locus using bacterial artificial chromosome technology. These lines expressed all six human tau protein isoforms on a Tau−/− background. We found that the human wild-type MAPT H1 locus was able to restore Aβ42-mediated impairment of LTP. In contrast, Aβ42 did not reduce LTP in slices in two independently generated transgenic lines expressing tau protein with the mutation N296H associated with frontotemporal dementia (FTD). Basal phosphorylation of tau measured as the ratio of AT8/Tau5 immunoreactivity was significantly reduced in N296H mutant hippocampal slices. Our data show that human MAPT is able to restore Aβ42-mediated inhibition of LTP in Tau−/− mice. These results provide further evidence that tau protein is central to Aβ-induced LTP impairment and provide a valuable tool for further analysis of the links between Aβ, human tau and impairment of synaptic function.

The Role of MAPT Haplotype H2 and Isoform 1N/4R in Parkinsonism of Older Adults.

Background and ObjectiveRecently, we have shown that the Parkinson’s disease (PD) susceptibility locus MAPT (microtubule associated protein tau) is associated with parkinsonism in older adults without a clinical diagnosis of PD. In this study, we investigated the relationship between parkinsonian signs and MAPT transcripts by assessing the effect of MAPT haplotypes on alternative splicing and expression levels of the most common isoforms in two prospective clinicopathologic studies of aging.Materials and Methodsusing regression analysis, controlling for age, sex, study and neuropathology, we evaluated 976 subjects with clinical, genotyping and brain pathology data for haplotype analysis. For transcript analysis, we obtained MAPT gene and isoform-level expression from the dorsolateral prefrontal cortex for 505 of these subjects.ResultsThe MAPT H2 haplotype was associated with lower total MAPT expression (p = 1.2x10-14) and global parkinsonism at both study entry (p = 0.001) and proximate to death (p = 0.050). Specifically, haplotype H2 was primarily associated with bradykinesia in both assessments (p<0.001 and p = 0.008). MAPT total expression was associated with age and decreases linearly with advancing age (p<0.001). Analysing MAPT alternative splicing, the expression of 1N/4R isoform was inversely associated with global parkinsonism (p = 0.008) and bradykinesia (p = 0.008). Diminished 1N/4R isoform expression was also associated with H2 (p = 0.001).ConclusionsOverall, our results suggest that age and H2 are associated with higher parkinsonism score and decreased total MAPT RNA expression. Additionally, we found that H2 and parkinsonism are associated with altered expression levels of specific isoforms. These findings may contribute to the understanding of the association between MAPT locus and parkinsonism in elderly subjects and in some extent to age-related neurodegenerative diseases.

Role of the Long Non-Coding RNA MAPT-AS1 in Regulation of Microtubule Associated Protein Tau (MAPT) Expression in Parkinson's Disease.

Studies investigating the pathogenic role of the microtubule associated protein tau (MAPT) gene in Parkinson’s disease (PD) have indicated that DNA methylation of the promoter region is aberrant in disease, leading to dysregulated MAPT expression. We examined two potential regulators of MAPT gene expression in respect to PD, a promoter-associated long non-coding RNA MAPT-AS1, and DNA methyltransferases (DNMTs), enzymes responsible for new and maintenance of DNA methylation. We assessed the relationship between expression levels of MAPT and the candidate MAPT-AS1, DNMT1, DNMT3A and DNMT3B transcripts in four brain regions with varying degrees of cell loss and pathology (putamen, anterior cingulate cortex, visual cortex and cerebellum) in N = 10 PD and N = 10 controls. We found a significant decrease in MAPT-AS1 expression in PD (p = 7.154 x 10−6). The transcript levels of both MAPT-AS1 (p = 2.569 x 10−4) and DNMT1 (p = 0.001) correlated with those of MAPT across the four brain regions, but not with each other. Overexpression of MAPT-AS1 decreased MAPT promoter activity by ∼2.2 to 4.3 fold in an in vitro luciferase assay performed in two cell lines (p ≤ 2.678 x 10−4). Knock-down expression of MAPT-AS1 led to a 1.3 to 6.3 fold increase in methylation of the endogenous MAPT promoter (p ≤ 0.011) and a 1.2 to 1.5 fold increased expression of the 4-repeat MAPT isoform transcript (p ≤ 0.013). In conclusion, MAPT-AS1 and DNMT1 have been identified as potential epigenetic regulators of MAPT expression in PD across four different brain regions. Our data also suggest that increased MAPT expression could be associated with disease state, but not with PD neuropathology severity.

Phosphorylation and isoform expression of microtubule-associated protein tau are regulated independently in the mouse brain

Event Abstract Back to Event Phosphorylation and isoform expression of microtubule-associated protein tau are regulated independently in the mouse brain Dilina Tuerde1*, Taeko Kimura1, Tomohiro Miyasaka2, Akiko Asada1, Kanae Ando1, Taro Saito1 and Shin-Ichi Hisanaga1* 1 Tokyo Metropolitan University, Department of Biological Sciences, Japan 2 Doshisha University, Faculty of Life and Medical Sciences Neuropathology, Japan Tau is a microtubule-associated protein, mainly expressed in axon of neurons. There are 6 isoforms in tau, which are produced by alternative mRNA splicing of N-terminal insertions and C-terminal microtubule-binding repeats. The C-terminal splicing produces 3-repeat (3R) and 4-repeart (4R) tau with different microtubule-binding ability. It is shown that isoforms and phosphorylation of tau change during neuronal development. In mouse brain 3R tau isoforms are expressed in embryonic and early postnatal days and replaced with 4R tau until postnatal day 20 (P20). Early postnatal tau resembles that of Alzheimer`s disease in their high phosphorylation states. Thus, it is important to understand the mechanism of highly phosphorylated postnatal tau. However, it is not entirely known how the changes in isoforms and phosphorylation of tau are regulated and related to each other. In order to address this question, we used Phos-tag SDS-PAGE, in which phosphorylated proteins are shifted upward remarkably depending on the number and site of phosphorylation. Phosphorylation of tau drops with the decrease in 3R tau expression during postnatal day 5 (P5) to 18 (P18). In contrast, 4R tau, whose expression began at around P9 and was not highly phosphorylated even when 3R tau was phosphorylated. Phosphorylation of 4R tau changed around P24, one week after 3R tau completed the change in phosphorylation. We also examined phosphorylation of human 3R tau which was knocked in mouse tau locus. Human 3R tau changed phosphorylation states at P20, slightly delayed after mouse tau even though its expression levels did not change. We also studied phosphorylation of tau in several brain regions, cerebral cortex, cerebellum, hippocampus and olfactory bulb. Tau was phosphorylated higher in olfactory bulb than other areas with stronger expression of 3R tau. Keywords: Brain, Phosphorylation, in vivo, neurone, protein Conference: 14th Meeting of the Asian-Pacific Society for Neurochemistry, Kuala Lumpur, Malaysia, 27 Aug - 30 Aug, 2016. Presentation Type: Poster Presentation Session Topic: 14th Meeting of the Asian-Pacific Society for Neurochemistry Citation: Tuerde D, Kimura T, Miyasaka T, Asada A, Ando K, Saito T and Hisanaga S (2016). Phosphorylation and isoform expression of microtubule-associated protein tau are regulated independently in the mouse brain. Conference Abstract: 14th Meeting of the Asian-Pacific Society for Neurochemistry. doi: 10.3389/conf.fncel.2016.36.00125 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 04 Aug 2016; Published Online: 11 Aug 2016. * Correspondence: Ms. Dilina Tuerde, Tokyo Metropolitan University, Department of Biological Sciences, Hachioji-shi, Tokyo, Japan, dilnara0616@gmail.com Dr. Shin-Ichi Hisanaga, Tokyo Metropolitan University, Department of Biological Sciences, Hachioji-shi, Tokyo, Japan, Shin-ichi.Hisanaga@frontiersin.org Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Dilina Tuerde Taeko Kimura Tomohiro Miyasaka Akiko Asada Kanae Ando Taro Saito Shin-Ichi Hisanaga Google Dilina Tuerde Taeko Kimura Tomohiro Miyasaka Akiko Asada Kanae Ando Taro Saito Shin-Ichi Hisanaga Google Scholar Dilina Tuerde Taeko Kimura Tomohiro Miyasaka Akiko Asada Kanae Ando Taro Saito Shin-Ichi Hisanaga PubMed Dilina Tuerde Taeko Kimura Tomohiro Miyasaka Akiko Asada Kanae Ando Taro Saito Shin-Ichi Hisanaga Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Effects of microtubule-associated protein tau expression on neural stem cell migration after spinal cord injury.

Our preliminary proteomics analysis suggested that expression of microtubule-associated protein tau is elevated in the spinal cord after injury. Therefore, the first aim of the present study was to examine tau expression in the injured spinal cord. The second aim was to determine whether tau can regulate neural stem cell migration, a critical factor in the successful treatment of spinal cord injury. We established rat models of spinal cord injury and injected them with mouse hippocampal neural stem cells through the tail vein. We used immunohistochemistry to show that the expression of tau protein and the number of migrated neural stem cells were markedly increased in the injured spinal cord. Furthermore, using a Transwell assay, we showed that neural stem cell migration was not affected by an elevated tau concentration in the outer chamber, but it was decreased by changes in intracellular tau phosphorylation state. These results demonstrate that neural stem cells have targeted migration capability at the site of injury, and that although tau is not a chemokine for targeted migration of neural stem cells, intracellular tau phosphorylation/dephosphorylation can inhibit cell migration.

Genome-wide Meta-analysis on the Sense of Smell Among US Older Adults.

Olfactory dysfunction is common among older adults and affects their safety, nutrition, quality of life, and mortality. More importantly, the decreased sense of smell is an early symptom of neurodegenerative diseases such as Parkinson disease (PD) and Alzheimer disease. However, the genetic determinants for the sense of smell have been poorly investigated. We here performed the first genome-wide meta-analysis on the sense of smell among 6252 US older adults of European descent from the Atherosclerosis Risk in Communities (ARIC) study, the Health, Aging, and Body Composition (Health ABC) study, and the Religious Orders Study and the Rush Memory and Aging Project (ROS/MAP). Genome-wide association study analysis was performed first by individual cohorts and then meta-analyzed using fixed-effect models with inverse variance weights. Although no SNPs reached genome-wide statistical significance, we identified 13 loci with suggestive evidence for an association with the sense of smell (Pmeta < 1 × 10). Of these, 2 SNPs at chromosome 17q21.31 (rs199443 in NSF, P = 3.02 × 10; and rs2732614 in KIAA1267-LRRC37A, P = 6.65 × 10) exhibited cis effects on the expression of microtubule-associated protein tau (MAPT, 17q21.31) in 447 frontal-cortex samples obtained postmortem and profiled by RNA-seq (P < 1 × 10). Gene-based and pathway-enrichment analyses further implicated MAPT in regulating the sense of smell in older adults. Similar results were obtained after excluding participants who reported a physician-diagnosed PD or use of PD medications. In conclusion, we provide preliminary evidence that the MAPT locus may play a role in regulating the sense of smell in older adults and therefore offer a potential genetic link between poor sense of smell and major neurodegenerative diseases.

Microtubule-associated protein tau (Mapt) is expressed in terminally differentiated odontoblasts and severely down-regulated in morphologically disturbed odontoblasts of Runx2 transgenic mice

Runx2 is an essential transcription factor for osteoblast and odontoblast differentiation and the terminal differentiation of chondrocytes. We have previously shown that the terminal differentiation of odontoblasts is inhibited in Runx2 transgenic {Tg(Col1a1-Runx2)} mice under the control of the 2.3-kb Col1a1 promoter, which directs the transgene expression to osteoblasts and odontoblasts. Odontoblasts show severe reductions in Dspp and nestin expression and lose their characteristic polarized morphology, including a long process extending to dentin, in Tg(Col1a1-Runx2) mice. We study the molecular mechanism of odontoblast morphogenesis by comparing gene expression in the molars of wild-type and Tg(Col1a1-Runx2) mice, focusing on cytoskeleton-related genes. Using microarray, we found that the gene expression of microtubule-associated protein tau (Mapt), a neuronal phosphoprotein with important roles in neuronal biology and microtubule dynamics and assembly, was high in wild-type molars but severely reduced in Tg(Col1a1-Runx2) molars. Immunohistochemical analysis revealed that Mapt was specifically expressed in terminally differentiated odontoblasts including their processes in wild-type molars but its expression was barely detectable in Tg(Col1a1-Runx2) molars. Double-staining of Mapt and Runx2 showed their reciprocal expression in odontoblasts. Mapt and tubulin co-localized in odontoblasts in wild-type molars. Immunoelectron microscopic analysis demonstrated Mapt lying around α-tubulin-positive filamentous structures in odontoblast processes. Thus, Mapt is a useful marker for terminally differentiated odontoblasts and might play an important role in odontoblast morphogenesis.