HECKMAN, M

Abstract Genetic studies have significantly advanced our understanding of tauopathies, yet the genetic aetiology of Pick’s disease, a rare 3-Repeat tauopathy, remains unclear. The MAPT p.A152T variant has been identified as a risk factor for Alzheimer’s disease and progressive supranuclear palsy, but its role in Pick’s disease is unknown. In this study, we examined the prevalence of MAPT p.A152T in the largest series of neuropathologically confirmed Pick’s disease cases to date (n = 401). Through genotyping, we identified a single mutation carrier in the Pick’s disease cohort (minor allele frequency = 0.12%). We previously reported MAPT p.A152T at a 0.20% frequency in healthy controls (n = 2456), suggesting that it does not associate with 3-Repeat tauopathy risk. To further investigate the effect of the variant on MAPT transcript expression, we used bulk RNA sequencing in Alzheimer’s disease and progressive supranuclear palsy A152T mutation carriers. We did not detect significant differences in 4-Repeat tau levels, though preliminary trends may indicate more nuanced effects that need to be examined with long-read sequencing in a larger series. Overall, our study suggests that MAPT p.A152T does not increase Pick’s disease risk and may instead be linked to 4-Repeat or mixed tau pathologies, warranting further functional investigation.

Introduction Parkinson's disease (PD) and Dementia with Lewy Bodies (DLB) are progressive neurodegenerative disorders characterized by alpha-synuclein pathology. As current therapies largely target symptoms, there is a clear need for disease-modifying treatments. Emerging evidence links these disorders to glucose metabolism dysregulation, suggesting antidiabetic agents may hold therapeutic potential. Methods This was a prospective, randomized, double-blind pilot study involving 12 subjects with PD or DLB to evaluate the tolerability and preliminary effects of a dipeptidyl peptidase 4 (DPP4) inhibitor (sitagliptin 100 mg) vs. sodium glucose like transporter 2 (SGLT2) inhibitor (dapagliflozin 10 mg) over a 4-week period, compared to a placebo. We assessed changes in Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) scores, cognitive function, and autonomic biomarkers. Both sitagliptin and dapagliflozin were well-tolerated, with no adverse events. While no significant changes were observed in cognitive scores, a significant difference was found in the change from baseline for MDS-UPDRS part 1 ( P = 0.008), part 2 ( P = 0.020), and total scores ( P = 0.047) when comparing the three groups. Discussion The dapagliflozin group showed more favorable trends in MDS-UPDRS scores. Limitations include small study size and duration as well as all participants had PD except one subject in the DPP4 inhibitor group with DLB. This pilot study suggests that these inhibitors are safe in PD and DLB patients. The preliminary findings, particularly the trends in the dapagliflozin group, provide a basis for larger-scale, long-term studies to confirm these potential symptomatic benefits and explore disease-modifying effects. Clinical trial registration https://clinicaltrials.gov/study/NCT06263673 , identifier: NCT06263673.

Abstract Background Individual environmental exposures, the exposome, can play an influential role in the development and progression of neurodegenerative diseases such as AD. The protein components of the main AD neuropathologies, amyloid (Aβ) plaques and tau neurofibrillary tangles (NFTs), can be measured using immunohistochemical and biochemical approaches. The main genetic risk factor for AD is the APOE e4 allele. APOE levels can also be measured in the brain. We hypothesize that social determinants of health, specifically alcohol and tobacco consumption, and the area deprivation index (ADI), could play a considerable role in severity of neuropathology and brain biochemical phenotypes of AD. Method We evaluated 478 neuropathologically characterized AD donors, from the Mayo Clinic Brain Bank. 469 samples had available biochemical measures (APOE, Aβ40, Aβ42, tau, and phospho‐tau (Thr231)), collected across three isolated fractions (soluble (TBS), membrane‐bound (TX), and insoluble (FA)) of the superior temporal gyrus. Exposome variables were extracted from the available records. ADI from the Neighborhood Atlas® version from the year 2015 was obtained from de‐identified addresses. ADI, smoking and alcohol were available for 263 of these donors and were examined for association with biochemical measures using linear regression adjusting for age at death and sex. Result Higher ADI levels representing neighborhoods with increased deprivation, were nominally associated (β=0.006, p =0.01) with soluble levels of APOE. Alcohol consumption was associated with lower levels of membrane bound APOE (β=‐0.23, p =0.04). Analysis with neuropathological variables including CAA ( N =454), Braak ( N =454), Thal ( N =454), Hippocampal sclerosis ( N =453), Lewy bodies ( N =455) will also be performed. Conclusion Different components of the social exposome may impact levels of core AD proteins. Additional analyses in expanded cohorts to further explore the associations with neuropathology are ongoing. We expect that understanding how the social exposome impacts specific aspects of neurodegenerative diseases will provide key insights into underlying, potentially modifiable, mechanisms of disease.