Biology subjects

Siebrand, C. J.

Publications and source records attributed to Siebrand, C. J..

5 recordsLinked to original sources

bioRxiv2026

In vitro comparison of Aβ-targeting SNIPR, synNotch, and TRUCK for cell-based drug delivery in Alzheimer's disease.

Pioneering research is adapting chimeric antigen receptors (CARs) from oncology to Alzheimers disease (AD) by targeting amyloid beta (A{beta}). Newer synthetic receptor systems can go beyond, transforming cells into targeted biological drug factories that can couple A{beta} detection to synthesis and secretion of genetically encoded therapeutics. Among candidate systems, T cells Redirected for Universal Cytokine Killing (TRUCK), synthetic Notch (synNotch), and Synthetic Intramembrane Proteolysis Receptors (SNIPR) have shown promise in oncology. Here, we adapt these platforms to AD using a shared A{beta}-targeting binding domain derived from Aducanumab (Aduhelm), coupled to inducible expression cassettes driving identical transgenes: secreted Metridia luciferase (MetLuc) and a Lecanemab (Leqembi)-based chimeric human-mouse antibody (chLecanemab). To validate these systems in vitro, Jurkat clones expressing each receptor were treated with oligomer-enriched A{beta} (A{beta}O) to model AD, and receptor output was quantified by media MetLuc levels and chLecanemab colocalization with A{beta} aggregates. For TRUCK systems, we show the A{beta}-targeting CAR successfully activated Jurkat cells by flow cytometry. We also show that six Nuclear Factor of Activated T-cells (NFAT) tandem repeat response elements (6xNFAT) paired with either minimal interleukin-2, synthetic TATA box, or minimal cytomegalovirus promoters resulted in functional regulatory regions. Despite this, all TRUCK variants failed to significantly upregulate MetLuc in response to A{beta}O. In contrast, both synNotch and SNIPR responded robustly to A{beta}O, with SNIPR outperforming synNotch in both MetLuc and chLecanemab production. These findings establish SNIPR and synNotch as promising platforms for future research on cell-based targeted therapeutic delivery in AD.

neuroscience↗

bioRxiv2025

Chimeric Antigen Receptors Discriminate Between Tau and Distinct Amyloid-Beta Species

Abstract/SummaryThe lack of a definitive cure for Alzheimers disease (AD) is fueling the search for innovative therapeutic strategies. Having revolutionized cancer immunotherapy, immune cell engineering with chimeric antigen receptors (CAR) is being explored to target AD. Whether CARs can recognize distinct amyloid-{beta} (A{beta}) species and tau neurofibrillary tangles (NFTs)--hallmark pathologies of AD--remains unclear. To investigate this, we engineered CARs based on AD antibodies targeting tau (E2814), A{beta} (Lecanemab and Aducanumab), and truncated pyroglutamate form of A{beta} (A{beta}p3-42; Donanemab and Remternetug). To evaluate CAR function, we established the murine DO11.10 hybridoma T-cell line as a practical and scalable testing platform. Our findings demonstrate that CARs can detect and discriminate between tau preformed fibrils (PFFs), A{beta}1-42, and A{beta}p3-42 aggregates. This highlights the potential of repurposing AD antibodies for CAR-based therapies to selectively target tau NFTs and distinct forms of A{beta} senile plaques.

synthetic biology↗

bioRxiv2025

A Human Neuron Alzheimer's Disease Model Reveals Barriers to Senolytic Translatability

Therapeutic successes in mouse models of Alzheimers disease (AD) largely fail to translate into clinical trials, with experimental drugs rarely validated in human models before being administered to humans. To address this, we developed an accessible method for long-term culture of commercially available primary human neurons and astrocytes, along with an amyloid-beta 1-42 (A{beta})-based in vitro AD model. Using this system, we evaluated two senolytic regimens previously shown to be effective in AD mouse models--Navitoclax and Dasatinib plus Quercetin (DQ)--and the natural killer cell line NK92 for emerging immune-mediated senescent cell ablation therapies. NK92 cells preferentially--but not exclusively--targeted A{beta}-treated neurons and astrocytes with senescent-like phenotypes. DQ demonstrated a safe profile for human neurons, but Navitoclax exhibited non-selective neurotoxicity. These findings highlight risks of Navitoclax and NK-based interventions and underscore the critical need for human-relevant models in the AD drug-development pipeline to improve safety and clinical translatability.

neuroscience↗

bioRxiv2024

Aβ-targeting synNotch Receptor for Alzheimer's Disease: Expanding Applications to Extracellular Protein Aggregates

The synthetic Notch receptor (synNotch) system is a versatile platform that induces gene transcription in response to extracellular signals. However, its application has been largely confined to membrane-bound targets due to specific activation requirements. Whether synNotch can also target extracellular protein aggregates, such as amyloid beta (A{beta}) in Alzheimers disease (AD), is unclear. To address this, we engineered an A{beta}-targeting synNotch receptor controlling the production of chimeric human-mouse versions of Lecanemab (Leqembi(R)) or Aducanumab (Aduhelm(R)), both FDA-approved antibodies for AD. We demonstrate that NIH 3T3 cells expressing this synNotch system detect and respond to extracellular A{beta} aggregates by synthesizing and secreting Aducanumab or Lecanemab. These findings broaden the potential applications of synNotch, extending its targets beyond membrane-bound proteins to extracellular protein aggregates, providing obvious benefits to research in this scientific arena.

synthetic biology↗

bioRxiv2022

Lipidomic profiling reveals age-dependent changes in complex plasma membrane lipids that regulate neural stem cell aging

The aging brain exhibits a decline in the regenerative populations of neural stem cells (NSCs), which may underlie age-associated defects in sensory and cognitive functions1-6. While mechanisms that restore old NSC function have started to be identified7-23, the role of lipids - especially complex lipids - in NSC aging remains largely unclear. Using lipidomic profiling by mass spectrometry, we identify age-related lipidomic signatures in young and old quiescent NSCs in vitro and in vivo. These analyses reveal drastic changes in several complex membrane lipid classes, including phospholipids and sphingolipids in old NSCs. Moreover, poly-unsaturated fatty acids (PUFAs) strikingly increase across complex lipid classes in quiescent NSCs during aging. Age-related changes in complex lipid levels and side chain composition are largely occurring in plasma membrane lipids, as revealed by lipidomic profiling of isolated plasma membrane vesicles. Experimentally, we find that aging is accompanied by modifications in plasma membrane biophysical properties, with a decrease in plasma membrane order in old quiescent NSCs in vitro and in vivo. To determine the functional role of plasma membrane lipids in aging NSCs, we performed genetic and supplementation studies. Knockout of Mboat2, which encodes a phospholipid acyltransferase, exacerbates age-related lipidomic changes in old quiescent NSCs and impedes their ability to activate. As Mboat2 expression declines with age, Mboat2 deficiency may drive NSC decline during aging. Interestingly, supplementation of plasma membrane lipids derived from young NSCs boosts the ability of old quiescent NSCs to activate. Our work could lead to lipid-based strategies for restoring the regenerative potential of NSCs in old individuals, which has important implications for countering brain decline during aging.

molecular biology↗