Biology subjects

Bellier, J.-P.

Publications and source records attributed to Bellier, J.-P..

3 recordsLinked to original sources

bioRxiv2025

CNS-Tau Specific Antibodies Illuminate Disease Signatures Across Tauopathies

BackgroundAlternative splicing of the MAPT gene produces distinct tau isoforms in the central and peripheral nervous systems (CNS and PNS), yet their respective biological and pathological roles remain poorly understood. Recent studies suggest that CNS-tau may play a key role in amyloid-{beta} associated neurodegeneration in Alzheimers disease (AD), but the absence of isoform-specific tools has limited both mechanistic insight and biomarker development. We aimed to develop and validate CNS-tau-specific monoclonal antibodies and assess their utility in neuropathology and fluid-based biomarker assays across AD and primary tauopathies. MethodsWe generated six recombinant rabbit monoclonal antibodies targeting a CNS-tau-specific sequence encoded by exons 4 and 5. Specificity and affinity were evaluated via biolayer interferometry, immunoblotting, and tau-expressing HEK293 models. The lead clone, LL-T-1-1, was tested in postmortem brain sections from AD (n = 23), progressive supranuclear palsy (PSP, n = 3), and corticobasal degeneration (CBD, n = 3). A second clone, LL-T-1-5, was optimized for use in plasma assays via an ultrasensitive nanoneedle platform, LoD < 1 pg/ml. ResultsLL-T-1-1 showed nanomolar affinity for CNS-tau and no cross-reactivity with PNS-tau. It selectively labeled dystrophic neurites in AD and all hallmark tau lesions in PSP and CBD without antigen retrieval. LL-T-1-5-based plasma assays revealed CNS-tau levels significantly correlated with cognitive scores (MMSE and QDRS) and differentiated impaired from unimpaired individuals. ConclusionsCNS-tau-specific antibodies LL-T-1-1 and LL-T-1-5 provide new tools for neuropathology and fluid biomarker development across tauopathies.

neuroscience↗

bioRxiv2024

Identification of Fibrinogen as a Plasma Protein Binding Partner for Lecanemab Biosimilar IgG: Implications for Alzheimer's Disease Therapy

ObjectiveRecombinant monoclonal therapeutic antibodies like lecanemab, which target amyloid beta in Alzheimers disease, offer a promising approach for modifying the disease progression. Due to its relatively short half-life, Lecanemab, administered as a bi-monthly infusion (typically 10mg/kg) has a relatively brief half-life. Interaction with abundant plasma proteins binder in the bloodstream can affect pharmacokinetics of drugs, including their half-life. In this study we investigated potential plasma protein binding interaction to lecanemab using lecanemab biosimilar. MethodsLecanemab biosimilar used in this study was based on publicly available sequences. ELISA and Western blotting were used to assess lecanemab biosimilar immunoreactivity in the fractions human plasma sample obtained through size exclusion chromatography. The binding of lecanemab biosimilar to candidate binders was confirmed by Western blotting, ELISA, and surface plasmon resonance analysis. ResultsUsing a combination of equilibrium dialysis, ELISA, and Western blotting in human plasma, we first describe the presence of likely plasma protein binding partner to lecanemab biosimilar, and then identify fibrinogen as one of them. Utilizing surface plasmon resonance, we confirmed that lecanemab biosimilar does bind to fibrinogen, although with lower affinity than to monomeric amyloid beta. InterpretationIn the context of lecanemab therapy, these results imply that fibrinogen levels could impact the levels of free antibodies in the bloodstream and that fibrinogen might serve as a reservoir for lecanemab. More broadly, these results indicate that plasma protein binding may be an important consideration when clinically utilizing therapeutic antibodies in neurodegenerative disease.

neuroscience↗

bioRxiv2023

Functional variations in gamma-secretase activity are critical determinants of the clinical, biomarker, and cognitive progression of autosomal dominant Alzheimer's disease

BackgroundThe balance between production, clearance, and toxicity of A{beta} peptides is central to Alzheimers disease (AD) pathobiology. Though highly variable in terms of age at symptom onset (AAO), hundreds of variants in PSEN1 cause autosomal dominant forms of AD (ADAD) with nearly complete penetrance. PSEN1 forms the catalytic core of the {gamma}-secretase complex and thereby directly mediates the production of longer, aggregation-prone A{beta} peptides relative to shorter, non-aggregating peptides. We hypothesized that the broad AAO and biomarker heterogeneity seen across ADAD would be predictable based on mutation-specific differences in the production of A{beta} species. MethodsA{beta}-37, 38, 40, 42, and 43 production was quantified from 161 unique PSEN1 variants expressed in HEK293 cells. Prediction of AAO was carried out in 106 variants with available AAO and then replicated in 55 variants represented across 190 PSEN1 mutation carriers who have detailed cognitive and biomarker data from the Dominantly Inherited Alzheimers Network (DIAN). ResultsVariations in A{beta} production across the 161 mutations examined in cell-based models were highly predictive of AAO. In those with corresponding in vivo data from the DIAN study, our cell-based {gamma}-secretase composite was strongly associated with biomarker and cognitive trajectories. ConclusionsThese findings elucidate the critical link between {gamma}-secretase function, A{beta} production, and AD progression and offer mechanistic support for the amyloid hypothesis. The approach used here represents a powerful tool to account for heterogeneity in disease progression in ADAD clinical trials and to assess the pathogenicity of variants of unknown significance or with limited family history.

neuroscience↗