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Introduction: Genetic studies have shown that variants in the microtubuleassociated protein tau (MAPT) gene, which encodes tau protein, can increase the risk for Alzheimer's disease (AD). Additionally, two haplotypes of the MAPT gene (H1 and H2) are associated with various neurodegenerative disorders, including AD. This study aimed to test the association of MAPT haplotypes (H1 and H2) and MAPT haplotype-tagging polymorphisms (rs1467967, rs242557, rs3785883, rs2471738, del-In9, rs7521) with AD. Methods: The study included 964 individuals: 113 with AD, 53 with mild cognitive impairment (MCI), 54 with other dementias, and 744 healthy controls. Results: The results showed that individuals carrying the A allele in the MAPT rs1467967 polymorphism, the GG genotype in the MAPT rs7521 polymorphism, and the G allele in the MAPT rs242557 polymorphism had worse performance on various neuropsychological tests. Carriers of the C allele in MAPT rs2471738 polymorphism and CC homozygotes also showed worse performance on neuropsychological tests and pathological levels of several cerebrospinal fluid (CSF) biomarkers. However, T allele carriers in the MAPT rs2471738 polymorphism were more represented among patients with dementia and apolipoprotein E (APOE) 4 carriers. Carriers of the H2 MAPT haplotype had worse performance on various neuropsychological tests, consistent with our previous study, which associated the H2 MAPT haplotype with pathological levels of CSF AD biomarkers. Regarding the MAPT rs3785883 polymorphism, further research is needed since both the AA and GG genotypes were associated with pathological levels of CSF and plasma AD biomarkers. Discussion: In conclusion, further genetic studies are needed to elucidate the role of MAPT haplotypes and MAPT haplotype-tagging polymorphisms in the development of AD. [ABSTRACT FROM AUTHOR]

Lipids play crucial roles in the susceptibility and brain cellular responses to Alzheimer's disease (AD) and are increasingly considered potential soluble biomarkers in cerebrospinal fluid (CSF) and plasma. To delineate the pathological correlations of distinct lipid species, we conducted a comprehensive characterization of both spatially localized and global differences in brain lipid composition in AppNL‐G‐F mice with spatial and bulk mass spectrometry lipidomic profiling, using human amyloid‐expressing (h‐Aβ) and WT mouse brains controls. We observed age‐dependent increases in lysophospholipids, bis(monoacylglycerol) phosphates, and phosphatidylglycerols around Aβ plaques in AppNL‐G‐F mice. Immunohistology‐based co‐localization identified associations between focal pro‐inflammatory lipids, glial activation, and autophagic flux disruption. Likewise, in human donors with varying Braak stages, similar studies of cortical sections revealed co‐expression of lysophospholipids and ceramides around Aβ plaques in AD (Braak stage V/VI) but not in earlier Braak stage controls. Our findings in mice provide evidence of temporally and spatially heterogeneous differences in lipid composition as local and global Aβ‐related pathologies evolve. Observing similar lipidomic changes associated with pathological Aβ plaques in human AD tissue provides a foundation for understanding differences in CSF lipids with reported clinical stage or disease severity. [ABSTRACT FROM AUTHOR]

Introduction: Genetic studies have shown that variants in the microtubule-associated protein tau ( MAPT ) gene, which encodes tau protein, can increase the risk for Alzheimer's disease (AD). Additionally, two haplotypes of the MAPT gene (H1 and H2) are associated with various neurodegenerative disorders, including AD. This study aimed to test the association of MAPT haplotypes (H1 and H2) and MAPT haplotype-tagging polymorphisms (rs1467967, rs242557, rs3785883, rs2471738, del-In9, rs7521) with AD., Methods: The study included 964 individuals: 113 with AD, 53 with mild cognitive impairment (MCI), 54 with other dementias, and 744 healthy controls., Results: The results showed that individuals carrying the A allele in the MAPT rs1467967 polymorphism, the GG genotype in the MAPT rs7521 polymorphism, and the G allele in the MAPT rs242557 polymorphism had worse performance on various neuropsychological tests. Carriers of the C allele in MAPT rs2471738 polymorphism and CC homozygotes also showed worse performance on neuropsychological tests and pathological levels of several cerebrospinal fluid (CSF) biomarkers. However, T allele carriers in the MAPT rs2471738 polymorphism were more represented among patients with dementia and apolipoprotein E ( APOE ) ɛ4 carriers. Carriers of the H2 MAPT haplotype had worse performance on various neuropsychological tests, consistent with our previous study, which associated the H2 MAPT haplotype with pathological levels of CSF AD biomarkers. Regarding the MAPT rs3785883 polymorphism, further research is needed since both the AA and GG genotypes were associated with pathological levels of CSF and plasma AD biomarkers., Discussion: In conclusion, further genetic studies are needed to elucidate the role of MAPT haplotypes and MAPT haplotype-tagging polymorphisms in the development of AD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Babić Leko, Španić Popovački, Willumsen, Nikolac Perković, Pleić, Zubčić, Langer Horvat, Vogrinc, Boban, Borovečki, Zemunik, de Silva and Šimić.)