Developing Topics.

The OGA inhibitor ASN90/FNP-223 has the potential for disease modification in neurodegenerative diseases. A phase 1 clinical program in healthy participants was performed to determine its suitability for subsequent studies in movement disorders and Alzheimer's disease (AD) patients. Clinical Study 1: A randomized, double-blind, placebo-controlled, first-in-human study to assess the safety, tolerability, pharmacokinetics, pharmacodynamics, and food effect of single and multiple doses of orally administered ASN90 in healthy adult and elderly participants. Clinical Study 2: A phase 1, open-label, positron emission tomography (PET) study in healthy participants to determine the relationship between plasma concentration and brain target occupancy of ASN90 following a single oral dose. To assess the safety, tolerability, pharmacokinetics, pharmacodynamics, and central nervous system (CNS) target engagement of ASN90 in healthy participants. ASN90 was considered safe and well tolerated with dose-proportional pharmacokinetics at steady-state up to oral doses of 500 mg twice daily. Cerebrospinal fluid-to-plasma ratios for mean peak and mean systemic exposures were in the range of 2.5%-4.6%. Investigation of CNS occupancy using a PET ligand demonstrated that target occupancy of greater than 98% in the brain of healthy participants can be achieved at doses that are clinically well tolerated. The phase 1 results of ASN90 in healthy participants provide strong support for its further development in progressive supranuclear palsy (PSP) and AD. Currently, Ferrer Internacional, S.A. is conducting a phase 2 study, known as PROSPER (ClinicalTrials.gov ID: NCT06355531), to evaluate the efficacy, safety, and pharmacokinetics of ASN90 in slowing the progression of PSP. © 2025 International Parkinson and Movement Disorder Society.

BackgroundBridging integrator 1 (BIN1), one of the most strongly associated gene with Alzheimer’s disease (AD). It has been reported to play a role in the pathological processes of AD; however, the exact mechanism has not yet been completely found.MethodAlzheimer’s Disease Neuroimaging Initiative (ADNI, N = 495) was the discovery cohort, and the Chinese Alzheimer’s Biomarker and LifestylE (CABLE, N = 619) study was used to replicate the results. Two BIN1 gene polymorphism (rs7561528 and rs744373) were included in the analysis. Multiple linear regression model was used to examine the BIN1 loci relationship with cerebrospinal fluid (CSF) AD biomarkers and alternative biomarker of microglial activation microglia‐soluble triggering receptor expressed on myeloid cells 2 (sTREM2). Causal mediation analysis was conducted through 10,000 bootstrapped iterations to explore the mediating effect of sTREM2 on AD pathology.ResultIn the ADNI database, we found a significant association between BIN1 loci (rs7561528 and rs744373) and the levels of CSF phosphorylated‐tau (P‐tau) (Pc = 0.017; 0.010, respectively) and total‐tau (T‐tau) (Pc = 0.011; 0.013, respectively). The BIN1 loci were also found to be correlated with the levels of CSF sTREM2 (Pc = 0.010; 0.008, respectively). Mediation analysis demonstrated that CSF sTREM2 partially mediated the association of the BIN1 loci with P‐tau (rs7561528: Prop = 20.9% of total effect; rs744373: Prop = 24.9% of total effect) and T‐tau (rs7561528: Prop = 36.6% of total effect; rs744373: Prop = 44.1% of total effect). The analysis in CABLE study replicated the mediation role of rs7561528.ConclusionThis study demonstrated correlation between BIN1 loci and CSF AD biomarkers as well as microglia biomarker, particularly in preclinical AD. Additionally, the link between BIN1 loci and AD pathology was partially mediated by CSF sTREM2

BackgroundTau deposition in brain is a pathological hallmark of some neurodegenerative disorders including Alzheimer’s disease (AD). Braak staging of post‐mortem tissue suggests pathological tau spreads through the brain via synaptically connected pathways, and specific tau isoforms containing the microtubule binding region (MTBR) are thought to be essential to form extracellular seeds that propagate pathology. Tau is cleaved at the mid‐domain and the N‐ter to mid‐domain species are actively secreted extracellularly, whereas MTBR‐tau show faster turn‐over and deposition in brain. Recently, we identified the MTBR regions (residues 299‐317 (HVPG) and 354‐369 (IGSL)) and the nearby region (residue 243‐254 (LQTA)) were specifically enriched in AD brain aggregates. However, if and how these species change in extracellular spaces under pathophysiogical conditions were not known. This work describes the behavior of the pathological species in extracellular spaces by analyzing human cerebrospinal fluid (CSF) with changes of disease progression.MethodWe established a method to quantify MTBR‐tau in CSF, consisting of chemical extraction followed by tryptic digestion and mass spectrometry analysis. This method was applied to the CSF analysis of AD participants (n=50 amyloid negative with CDR=0‐1, n=50 amyloid positive with CDR=0‐2). A subset of these participants was followed longitudinally (2‐9 years).ResultOur method revealed that (1) MTBR‐tau were specifically increased in amyloid positive group and HVPG was the most significantly increased even in clinically asymptomatic stages, (2) the increases of HVPG and IGSL were saturated after symptomatic onset, whereas LQTA continued to increase even after the clinical onset, and (3) the concentration of LQTA showed the highest correlation with tau pathology as measured by positron emission tomography (PET) for tau (Pearson r=0.84, n=35) as well as cognitive testing measures.ConclusionMTBR‐tau enriched in AD brain aggregates are increased in AD CSF. These findings suggest HVPG and LQTA in CSF could be promising biomarkers to recapitulate amyloid status and tau pathology in AD, respectively. Notably, only LQTA showed the continuous increase along to disease progression in terms of tau‐PET as well as amyloid status and cognitive decline, which suggests the region is key to differentiate tau pathology in AD.

BackgroundIt has been documented that β‐amyloid (Aβ) deposition, tau pathology and neuronal degeneration precedes clinical symptoms in autosomal dominant Alzheimer's disease (AD). Since the divergence on pathogenesis between sporadic and familial AD limits the extension of these findings to sporadic AD, where and magnitude of pathologic processes in sporadic AD are of significant importance to clinical management.MethodIn this longitudinal study, we analyzed data from 982 ADNI participants with abnormal amyloid accumulations who underwent cerebrospinal fluid (CSF) test, brain imaging and cognitive assessments. We compared the levels of clinical outcomes and biomarkers at baseline and the rates of change in follow‐up between different stages of AD. The slope of the regression model over years was applied to estimate rates of change for Aβ deposition, tau alteration, hypometabolism, brain atrophy, and cognitive decline.ResultIn total 167 healthy controls, 133 patients with preclinical AD, 451 patients with MCI due to AD, and 231 patients with dementia due to AD were studied. The levels of clinical and biomarkers at baseline and their change rates at follow‐up significantly differed among the four groups. In terms of average years, Aβ deposition was observed over a range of 45·6 years for CSF Aβ, and 31·1 years with amyloid imaging, although Aβ markers began to be abnormal at 27·8 years for CSF Aβ and 26·3 years for neuroimaging. When Aβ markers exceeded the threshold, CSF tau and other non‐ Aβ markers started to change, and patients were estimated to take 29·1 years (CSF tau),12·7 years (memory), 12·2 years (hippocampus atrophy), 10·1years (hypometabolism) to transition from clinically normal to dementia. Finally, CSF p‐tau significantly increased as dementia onset approached.ConclusionOur results reveal the trajectory of biomarkers in sporadic Alzheimer's disease is led by Aβ accumulation, followed by CSF tau change, memory deficits, brain atrophy, hypometabolism, cognitive decline, and lastly CSF p‐tau increase.

A multiscale model to explain the spatiotemporal progression of amyloid beta and tau pathology in Alzheimer's disease.

Identifying cerebrospinal fluid measures of the microtubule binding region of tau (MTBR-tau) species that reflect tau aggregation could provide fluid biomarkers that track Alzheimer's disease related neurofibrillary tau pathological changes. We examined the cerebrospinal fluid (CSF) MTBR-tau species in dominantly inherited Alzheimer's disease (DIAD) mutation carriers to assess the association with Alzheimer's disease (AD) biomarkers and clinical symptoms. Cross-sectional and longitudinal CSF from 229 DIAD mutation carriers and 130 mutation non-carriers had sequential characterization of N-terminal/mid-domain phosphorylated tau (p-tau) followed by MTBR-tau species and tau positron emission tomography (tau PET), other soluble tau and amyloid biomarkers, comprehensive clinical and cognitive assessments, and brain magnetic resonance imaging of atrophy. CSF MTBR-tau species located within the putative "border" region and one species corresponding to the "core" region of aggregates in neurofibrillary tangles (NFTs) increased during the presymptomatic stage and decreased during the symptomatic stage. The "border" MTBR-tau species were associated with amyloid pathology and CSF p-tau; whereas the "core" MTBR-tau species were associated stronger with tau PET and CSF measures of neurodegeneration. The ratio of the border to the core species provided a continuous measure of increasing amounts that tracked clinical progression and NFTs. Changes in CSF soluble MTBR-tau species preceded the onset of dementia, tau tangle increase, and atrophy in DIAD. The ratio of 4R-specific MTBR-tau (border) to the NFT (core) MTBR-tau species corresponds to the pathology of NFTs in DIAD and change with disease progression. The dynamics between different MTBR-tau species in the CSF may serve as a marker of tau-related disease progression and target engagement of anti-tau therapeutics. ANN NEUROL 2023;93:1158-1172.

Apolipoprotein E (ApoE) is the major genetic risk factor for sporadic Alzheimer's Disease (AD). Some studies showed a relationship between ApoE4 genotype and the cerebrospinal fluid (CSF) biomarkers (β-amyloid42, p-Tau, t-Tau), as well as with cognitive status. In this sense, it could be interesting to develop an approach to establish amyloid status in a minimally invasive way. The present study assessed the ApoE genotype in different participant groups (mild cognitive impairment due to AD (MCI-AD), mild/moderate dementia due to AD, MCI not due to AD (MCI not AD), other neurological diseases, healthy participants) (n = 342). As expected, the ApoE4 allele was more prevalent in AD patients, characterized by impairment in CSF β-amyloid42 levels (Aβ +), than in the other groups (Aβ -). In this sense, ApoE4-carrier subjects showed lower CSF levels for β-amyloid42 and higher CSF levels for t-Tau and p-Tau. From this, a multivariate model to predict Aβ status was developed by means of partial least square analysis (PLS) and predictive variables (ApoE genotype, cognitive score, sex, age). This model showed suitable AUC-ROC 0.792 (95% CI, 0.744-0.840) and predictive negative value (81.6%). ApoE genotype could be useful in detecting CSF β-amyloid42 impairment associated with early AD development.

The total amount of hyperphosphorylated tau protein (p-tau load), present as neurofibrillary tangles (NFTs), neuropil threads or plaque neurites, was quantified in the frontal cortex of 109 cases of sporadic Alzheimer's disease (AD) and 35 cases of familial AD due to missense mutations in the presenilin-1, presenilin-2 and amyloid precursor protein genes. p-tau load was inversely correlated with age at onset of illness in both sporadic and familial AD but not with duration of disease. There was no difference in p-tau load between cases of familial AD and others with sporadic AD, matching the familial cases for apolipoprotein E (APO E) genotype. However, p-tau was greater in cases of familial and sporadic AD in the presence of APO E epsilon4 allele and increased with gene dose. Conversely, p-tau load tended to be lower when epsilon2 allele was present. In sporadic AD, tau load was highly significantly correlated with amyloid beta40 (Abeta40), but not Abeta42(43), load. These data indicate that the burden of pathological tau deposited in the brain in both familial and sporadic AD is favoured in the presence of APO E epsilon4 allele and also related to the amount of Abeta40, this also being higher when epsilon4 allele is present. Abeta40 plaques are rich in microglial cells and it is possible that p-tau pathology in AD is triggered by reaction of microglial cells to the presence of Abeta40 and not this peptide directly.

Clearance of tau seeds by immunization with tau antibodies is currently evaluated as therapeutic strategy to block the spreading of tau pathology in Alzheimer's disease and other tauopathies. Preclinical evaluation of passive immunotherapy is performed in different cellular culture systems and in wild-type and human tau transgenic mouse models. Depending on the preclinical model used, tau seeds or induced aggregates can either be of mouse, human or mixed origin. We aimed to develop human and mouse tau-specific antibodies to discriminate between the endogenous tau and the introduced form in preclinical models. Using hybridoma technology, we developed human and mouse tau-specific antibodies that were then used to develop several assays to specifically detect mouse tau. Four antibodies, mTau3, mTau5, mTau8, and mTau9, with a high degree of specificity for mouse tau were identified. Additionally, their potential application in highly sensitive immunoassays to measure tau in mouse brain homogenate and cerebrospinal fluid is illustrated, as well as their application for specific endogenous mouse tau aggregation detection. The antibodies reported here can be very important tools to better interpret the results obtained from different model systems as well as to study the role of endogenous tau in tau aggregation and pathology observed in the diverse mouse models available.

IntroductionHeparin binding proteins (HBPs) with roles in extracellular matrix assembly are strongly correlated to β-amyloid (Aβ) and tau pathology in Alzheimer’s disease (AD) brain and cerebrospinal fluid (CSF). However, it remains challenging to detect these proteins in plasma using standard mass spectrometry-based proteomic approaches.MethodsWe employed heparin-affinity chromatography, followed by off-line fractionation and tandem mass tag mass spectrometry (TMT-MS), to enrich HBPs from plasma obtained from AD (n = 62) and control (n = 47) samples. These profiles were then correlated to Aβ, tau and phosphorylated tau (pTau) CSF biomarkers and plasma pTau181 from the same individuals, as well as a consensus brain proteome network to assess the overlap with AD brain pathophysiology.ResultsHeparin enrichment from plasma was highly reproducible, enriched well-known HBPs like APOE and thrombin, and depleted high-abundant proteins such as albumin. A total of 2865 proteins, spanning 10 orders of magnitude in abundance, were measured across 109 samples. Compared to the consensus AD brain protein co-expression network, we observed that specific plasma proteins exhibited consistent direction of change in both brain and plasma, whereas others displayed divergent changes, highlighting the complex interplay between the two compartments. Elevated proteins in AD plasma, when compared to controls, included members of the matrisome module in brain that accumulate with Aβ deposits, such as SMOC1, SMOC2, SPON1, MDK, OLFML3, FRZB, GPNMB, and the APOE4 proteoform. Additionally, heparin-enriched proteins in plasma demonstrated significant correlations with conventional AD CSF biomarkers, including Aβ, total tau, pTau, and plasma pTau181. A panel of five plasma proteins classified AD from control individuals with an area under the curve (AUC) of 0.85. When combined with plasma pTau181, the panel significantly improved the classification performance of pTau181 alone, increasing the AUC from 0.93 to 0.98. This suggests that the heparin-enriched plasma proteome captures additional variance in cognitive dementia beyond what is explained by pTau181.ConclusionThese findings support the utility of a heparin-affinity approach coupled with TMT-MS for enriching amyloid-associated proteins, as well as a wide spectrum of plasma biomarkers that reflect pathological changes in the AD brain.

Although fatty acid oxidation is associated with Alzheimer's disease (AD) pathology, no links have been established between brain lipids and excreted oxidized products. We hypothesize that oxidation of brain polyunsaturated fatty acids (PUFA) can generate dicarboxylic acids (DCA) excreted in urine by AD subjects at different rates compared with cognitively healthy (CH) subjects. Furthermore, this trend can be extended to differentiate CH subjects with normal cerebrospinal fluid (CSF) Aβ 42 /tau ratios (CH‐NAT) and CH subjects with pathological CSF Aβ 42 /tau ratios (CH‐PAT). Subjects > 70 years were classified as CH (n=64) or AD (n=26) after neuropsychological assessment. CSF Aβ 42 and Tau levels were determined using an ELISA‐based method and a logistic regression of Aβ 42 /tau ratios used to classify CH‐NAT and CH‐PAT. CSF was fractionated and PUFA levels quantified in supernatant fluid (SF), nanoparticles (NP), and unesterified fatty acid (UFA). DCA was derivatized to pentafluorobenzyl ester, and quantified using gas chromatography and isotope dilution negative ion chemical ionization mass spectrometry. PUFA data is expressed as a percentage of fatty acids detected in CSF fractions while DCA is calculated as a percentage of 7 DCAs (C4–C10) in urine. Links between urinary DCAs and CSF PUFAs were determined using Spearman's ranked correlation. C10 DCA negatively correlated with 6 of 8 PUFAs in SF from CH and also negatively correlated with C20:3n‐3 and C22:6n‐3 in SF from CH‐NAT. In contrast, C9 DCA negatively correlated with 7 of 8 PUFAs in SF from AD. C6 and C8 DCAs positively correlated with SF C18:3n‐3 and C20:3n‐3 in AD, respectively, while C6 DCA negatively correlated with SF C18:2n‐6 from CH‐NAT. C4 DCA negatively correlated with C18:2n‐6, C20:4n‐6, and C22:6n‐3 in SF from CH‐PAT, while C7 DCA positively correlated with C20:4n‐6 in SF from CH‐PAT. In the NP fraction of CH, C4 DCA positively correlated with C20:2n‐6, C20:3n‐3, C20:5n‐3, and C22:5n‐3 PUFAs, while C8 DCA negatively correlated with C20:5n‐3. Only C9 DCA positively correlated with C20:4n‐6 in AD NP fractions. Interestingly, no correlations were found in the NP fraction from CH‐NAT. However, C8 DCA negatively correlated with NP C20:3n‐3, C20:5n‐3, and C22:5n‐3 and C4 DCA positively correlated with NP C20:5n‐3 from CH‐PAT. For UFA of CH, C6 DCA negatively correlated with C20:2n‐6, C20:3n‐3, and C22:6n‐3, while C5 and C7 DCAs positively correlated with homo‐γ‐C20:3n‐6 and C18:2n‐6, respectively. For UFA of CH‐NAT, C4 DCA positively correlated with homo‐γ‐C20:3n‐6, C5 and C8 DCAs negatively correlated with homo‐γ‐C20:3n‐6, and C7 DCA negatively correlated with C18:2n‐6. C5 DCA positively correlated with C18:2n‐6 in UFA from CH‐PAT. C8 DCA positively correlated with unesterified C22:6n‐3, while C9 DCA negatively correlated with unesterified C20:5n‐3 in AD subjects. Differential correlation of urinary DCAs with CSF PUFAs in clinical groups suggests a link with AD pathology. PUFAs and DCAs that segregate CH‐NAT from CH‐PAT are potential biomarkers of early AD. Support or Funding Information L.K. Whittier and the Helen Posthuma Foundations This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

INTRODUCTIONAmyloid beta and tau pathology are the hallmarks of sporadic Alzheimer's disease (AD) and autosomal dominant AD (ADAD). However, Lewy body pathology (LBP) is found in ≈ 50% of AD and ADAD brains.METHODSUsing an α‐synuclein seed amplification assay (SAA) in cerebrospinal fluid (CSF) from asymptomatic (n = 26) and symptomatic (n = 27) ADAD mutation carriers, including 12 with known neuropathology, we investigated the timing of occurrence and prevalence of SAA positive reactivity in ADAD in vivo.RESULTSNo asymptomatic participant and only 11% (3/27) of the symptomatic patients tested SAA positive. Neuropathology revealed LBP in 10/12 cases, primarily affecting the amygdala or the olfactory areas. In the latter group, only the individual with diffuse LBP reaching the neocortex showed α‐synuclein seeding activity in CSF in vivo.DISCUSSIONResults suggest that in ADAD LBP occurs later than AD pathology and often as amygdala‐ or olfactory‐predominant LBP, for which CSF α‐synuclein SAA has low sensitivity.HighlightsCerebrospinal fluid (CSF) real‐time quaking‐induced conversion (RT‐QuIC) detects misfolded α‐synuclein in ≈ 10% of symptomatic autosomal dominant Alzheimer's disease (ADAD) patients.CSF RT‐QuIC does not detect α‐synuclein seeding activity in asymptomatic mutation carriers.Lewy body pathology (LBP) in ADAD mainly occurs as olfactory only or amygdala‐predominant variants.LBP develops late in the disease course in ADAD.CSF α‐synuclein RT‐QuIC has low sensitivity for focal, low‐burden LBP.

PTI-125 Reduces Biomarkers of Alzheimer's Disease in Patients.

The insufficiency and heterogeneity of research to date primarily leads to a state of uncertainty regarding the value of CSF testing of t-tau, p-tau or p-tau/ABeta ratio for the diagnosis of Alzheimer's disease in current clinical practice. Particular attention should be paid to the risk of misdiagnosis and overdiagnosis of dementia (and therefore over-treatment) in clinical practice. These tests, like other biomarker tests which have been subject to Cochrane DTA reviews, appear to have better sensitivity than specificity and therefore might have greater utility in ruling out Alzheimer's disease as the aetiology to the individual's evident cognitive impairment, as opposed to ruling it in. The heterogeneity observed in the few studies awaiting classification suggests our initial summary will remain valid. However, these tests may have limited clinical value until uncertainties have been addressed. Future studies with more uniformed approaches to thresholds, analysis and study conduct may provide a more homogenous estimate than the one that has been available from the included studies we have identified.

IntroductionWe examine the role of brain apolipoprotein B (apoB) as a putative marker of early tau pathology and cognitive decline.MethodsCerebrospinal fluid (CSF) samples from cognitively normal and Alzheimer's disease (AD) participants were collected to measure protein levels of apoB and AD biomarkers amyloid beta (Aβ), t‐tau and p‐tau, as well as synaptic markers GAP43, SYNAPTOTAGMIN‐1, synaptosome associated protein 25 (SNAP‐25), and NEUROGRANIN. CSF apoB levels were contrasted with positron emission tomography (PET) scan measures of Aβ (18F‐NAV4694) and Tau (flortaucipir) along with cognitive assessment alterations over 6 to 8 years.ResultsCSF apoB levels were elevated in AD participants and correlated with t‐tau, p‐tau, and the four synaptic markers in pre‐symptomatic individuals. In the latter, CSF apoB levels correlated with PET flortaucipir‐binding in entorhinal, parahippocampal, and fusiform regions. Baseline CSF apoB levels were associated with longitudinal visuospatial cognitive decline.DiscussionCSF apoB markedly associates with early tau dysregulation in asymptomatic subjects and identifies at‐risk individuals predisposed to develop visuospatial cognitive decline over time.