Tau gene promoter rs242557 and allele-specific protein binding

HMGA1 deficiency: a pathogenic link between tau pathology and insulin resistance

BACKGROUND

Growing evidence links tau-related neurodegeneration with insulin resistance and type 2 diabetes (T2D), though the underlying mechanisms remain unclear. Our previous research identified HMGA1 as crucial for insulin receptor (INSR) expression, with defects in the HMGA1 gene associated with insulin resistance and T2D. Here, we explore HMGA1 deficiency as a potential contributor to tauopathies, such as Alzheimer's disease (AD), and its connection to insulin resistance.

METHODS

Immunoblot analyses, protein-DNA interaction studies, ChIP-qPCR, and reporter gene assays were conducted in human and mouse neuronal cell models. Tau immunohistochemistry, behavioural studies, and brain glucose metabolism were analysed in Hmga1-knockout mice. Additionally, a case-control study investigated the relationship between HMGA1 and tau pathology in patients with tauopathy, carrying or not the HMGA1 rs146052672 variant, known to reduce HMGA1 protein levels and increase the risk of insulin resistance and T2D.

FINDINGS

We show that HMGA1 regulates tau protein expression primarily through the specific repression of MAPT gene transcription. In both human neuronal cells and primary mouse neurons, tau mRNA and protein levels were inversely correlated with HMGA1 expression. This inverse relationship was further confirmed in the brain of Hmga1-knockout mice, where tau was overexpressed, INSR was downregulated, and brain glucose uptake was impaired. Additionally, the rs146052672 variant was more common in patients with tauopathy (12/69, 17.4%) than in controls (10/200, 5.0%) (p = 0.001), and carriers of this variant exhibited more severe disease progression and poorer therapeutic outcomes.

INTERPRETATION

These findings suggest that HMGA1 deficiency may drive tau pathology, linking tauopathies to insulin resistance and providing new insights into the relationship between metabolic and neurodegenerative disorders. Furthermore, our observation that over 17% of individuals with tauopathy exhibit a deficit in HMGA1 protein production could have significant clinical implications, potentially guiding the development of therapeutic strategies targeting this specific defect.

FUNDING

See acknowledgements section.

Whole-Genome Sequencing Analysis Reveals New Susceptibility Loci and Structural Variants Associated with Progressive Supranuclear Palsy

Background

Progressive supranuclear palsy (PSP) is a rare neurodegenerative disease characterized by the accumulation of aggregated tau proteins in astrocytes, neurons, and oligodendrocytes. Previous genome-wide association studies for PSP were based on genotype array, therefore, were inadequate for the analysis of rare variants as well as larger mutations, such as small insertions/deletions (indels) and structural variants (SVs).

Method

In this study, we performed whole genome sequencing (WGS) and conducted association analysis for single nucleotide variants (SNVs), indels, and SVs, in a cohort of 1,718 cases and 2,944 controls of European ancestry. Of the 1,718 PSP individuals, 1,441 were autopsy-confirmed and 277 were clinically diagnosed.

Results

Our analysis of common SNVs and indels confirmed known genetic loci at MAPT, MOBP, STX6, SLCO1A2, DUSP10, and SP1, and further uncovered novel signals in APOE, FCHO1/MAP1S, KIF13A, TRIM24, TNXB, and ELOVL1. Notably, in contrast to Alzheimer's disease (AD), we observed the APOE ε2 allele to be the risk allele in PSP. Analysis of rare SNVs and indels identified significant association in ZNF592 and further gene network analysis identified a module of neuronal genes dysregulated in PSP. Moreover, seven common SVs associated with PSP were observed in the H1/H2 haplotype region (17q21.31) and other loci, including IGH, PCMT1, CYP2A13, and SMCP. In the H1/H2 haplotype region, there is a burden of rare deletions and duplications (P = 6.73×10-3) in PSP.

Conclusions

Through WGS, we significantly enhanced our understanding of the genetic basis of PSP, providing new targets for exploring disease mechanisms and therapeutic interventions.

Genetic influences on cognition in progressive supranuclear palsy

BACKGROUND

Cognitive dysfunction is common in progressive supranuclear palsy, but the influence of genetics on cognition in this disorder has not been well studied. The objective of this study was to investigate the effect of genes previously identified as risk alleles, including microtubule-associated protein tau, myelin-associated oligodendrocyte basic protein, eukaryotic translation initiation factor 2-alpha kinase 3, and syntaxin 6, as well as apolipoprotein E, on cognitive function in progressive supranuclear palsy.

METHODS

The sample was composed of 305 participants who met criteria for possible or probable progressive supranuclear palsy. Genetic information was determined by TaqMan genotyping assays. A neuropsychological battery was administered to all study participants. Measures included in the battery evaluated for general cognition, executive function, memory, attention, language, and visuospatial ability.

RESULTS

Cognition did not vary significantly between individuals homozygous or heterozygous for the microtubule-associated protein tau H1 haplotype. However, cognition varied significantly at the subhaplotype level, with carriers of the microtubule-associated protein tau rs242557/A allele, which marks the H1c subhaplotype, performing better than noncarriers on measures of general cognitive function, executive function, and attention. No associations were found for other genes.

CONCLUSIONS

The results of the current study indicate that variations in microtubule-associated protein tau influence cognition in progressive supranuclear palsy. Although the H1c-specific rs242557/A allele is a risk factor for progressive supranuclear palsy, carriers of this allele may exhibit better cognition than non-carriers in patients with the atypical parkinsonian syndrome. Further studies are needed. © 2017 International Parkinson and Movement Disorder Society.

Monoaminergic neuropathology in Alzheimer's disease

None of the proposed mechanisms of Alzheimer's disease (AD) fully explains the distribution patterns of the neuropathological changes at the cellular and regional levels, and their clinical correlates. One aspect of this problem lies in the complex genetic, epigenetic, and environmental landscape of AD: early-onset AD is often familial with autosomal dominant inheritance, while the vast majority of AD cases are late-onset, with the ε4 variant of the gene encoding apolipoprotein E (APOE) known to confer a 5-20 fold increased risk with partial penetrance. Mechanisms by which genetic variants and environmental factors influence the development of AD pathological changes, especially neurofibrillary degeneration, are not yet known. Here we review current knowledge of the involvement of the monoaminergic systems in AD. The changes in the serotonergic, noradrenergic, dopaminergic, histaminergic, and melatonergic systems in AD are briefly described. We also summarize the possibilities for monoamine-based treatment in AD. Besides neuropathologic AD criteria that include the noradrenergic locus coeruleus (LC), special emphasis is given to the serotonergic dorsal raphe nucleus (DRN). Both of these brainstem nuclei are among the first to be affected by tau protein abnormalities in the course of sporadic AD, causing behavioral and cognitive symptoms of variable severity. The possibility that most of the tangle-bearing neurons of the LC and DRN may release amyloid β as well as soluble monomeric or oligomeric tau protein trans-synaptically by their diffuse projections to the cerebral cortex emphasizes their selective vulnerability and warrants further investigations of the monoaminergic systems in AD.