Biology subjects

Stoddard, A.

Publications and source records attributed to Stoddard, A..

6 recordsLinked to original sources

bioRxiv2026

Image-Guided Injectable Niche for Hepatocyte Transplantation

Liver transplantation remains the standard of care for end-stage liver failure, yet it is constrained by donor scarcity, surgical complexity, and restricted access for many patients. Cell-based therapies offer a potential alternative, yet their translation has been hindered by low engraftment, poor localization, and a lack of delivery strategies that are both effective and minimally invasive. To address these challenges, we developed a new approach termed INSITE (Injected Self-assembled Image-guided Tissue Ensembles), an injectable platform composed of primary human hepatocytes and hydrogel microspheres that can be delivered by image-guided injection and assembled in situ into supportive, vascularizable scaffolds. In vivo, ultrasound-guided delivery into an ectopic site enabled precise graft localization, persistent visibility under noninvasive imaging, and vascular integration. Hepatocytes within these niches remained confined to the scaffold and maintained long-term functional activity. Furthermore, tuning material properties allowed control over scaffold remodeling and vascular recruitment, providing a means to enhance graft function. By integrating image-guided delivery with a modular and supportive scaffold, INSITE establishes a clinically compatible strategy for advancing minimally invasive cell therapies.

bioengineering↗

bioRxiv2019

High Throughput Screening at the Membrane Interface Reveals New Inhibitors of Amyloid-β

Amyloid-{beta} aggregation at the cell-membrane of neruonal cells is implicated as a source of toxicity for Alzheimers disease. Small molecules have been studied for their ability to supress amyloid aggregation and toxicity, but the presence of membranes negate their activity. Here, we have identified 5 small molecules that are active at the membrane interface.

biochemistry↗

bioRxiv2019

Apolipoprotein A-I Mimetic 4F Peptide Generates Amyloid Cytotoxins by Forming Hetero-oligomers with β-amyloid

Apolipoproteins are involved in pathological conditions of Alzheimers disease (AD), truncated apolipoprotein fragments and {beta}-amyloid (A{beta}) peptides coexist as neurotoxic heteromers within the plaques. Therefore, it is important to investigate these complexes at the molecular level to better understand their properties and roles in the pathology of AD. Here, we present a mechanistic insight into such heteromerization using a structurally homologue apolipoprotein fragment of apoA-I (4F) complexed with A{beta}(M1-42) and characterize their toxicity. The 4F peptide slows down the aggregation kinetics of A{beta}(M1-42) by constraining its structural plasticity. NMR and CD experiments identified 4F-A{beta}(M1-42) heteromers as being comprised of unstructured A{beta}(M1-42) and helical 4F. A uniform {approx}2-fold reduction in A{beta}42 15N/1H NMR signal intensities with no observable chemical shift perturbation indicated the formation of a large complex, which was further confirmed by diffusion NMR experiments. Microsecond scale atomistic molecular dynamics simulations showed that 4F interaction with A{beta}(M1-42) is electrostatically driven and induces unfolding of A{beta}(M1-42). Neurotoxicity profiling of A{beta}(M1-42) complexed with 4F confirms a significant reduction in cell-viability and neurite growth. The molecular architecture of heteromerization between 4F and A{beta}(M1-42) discovered in this study provides evidence towards our understanding of the role of apolipoproteins or their truncated fragments in exacerbating AD pathology.

biophysics↗

bioRxiv2019

The effect of number of healthcare visits on study sample selection and prevalence estimates in electronic health record data

IntroductionFew studies have addressed how to select a study sample when using electronic health record (EHR) data.\n\nMethodsYear 2016 EHR data from three health systems was used to examine how alternate definitions of the study sample, based on number of healthcare visits in one year, affected measures of disease period prevalence. Curated collections of ICD-9, ICD-10, and SNOMED codes were used to define three diseases.\n\nResultsAcross all health systems, increasing the minimum required number of visits to be included in the study sample monotonically increased crude period prevalence estimates. The rate at which prevalence estimates increased with number of visits varied across sites and across diseases.\n\nConclusionsWhen using EHR data authors must carefully describe how a study sample is identified and report outcomes for a range of sample definitions, so that others can assess the sensitivity of reported results to sample definition in EHR data.

epidemiology↗

bioRxiv2018

Alzheimer’s Amyloid-Beta Intermediates Generated by Polymer-Nanodiscs

Polymethacrylate-copolymer (PMA) encased lipid-nanodiscs (~10 nm) and macro-nanodiscs (>15 nm) are used to study A{beta}1-40 aggregation. We demonstrate that PMA-nanodiscs form a ternary association with A{beta} and regulate its aggregation kinetics by trapping intermediates. Results demonstrating reduced neurotoxicity of nanodisc-bound A{beta} oligomers are also reported.

biophysics↗

bioRxiv2018

Cationic polymethacrylate-copolymer acts as an agonist for beta-amyloid and antagonist for amylin fibrillation

In human, amyloid-beta (A{beta}) and islet amyloid polypeptide (hIAPP) aggregations are linked to Alzheimers disease and Type-2 Diabetes, respectively. There is significant interest in better understanding the aggregation process by using chemical tools. Here, we show the ability of a cationic polymethacrylate-copolymer (PMAQA) to quickly induce {beta}-hairpin structure and promote fibrillation in A{beta}40, and to constrain the conformational plasticity of hIAPP for several days and inhibit its aggregation at sub-micromolar concentrations. NMR experiments and atomistic molecular dynamics simulations reveal that PMAQA electrostatically interacts with A{beta}40s Glu22 and Asp23 followed by {beta}-sheet induction while it binds strongly to the closest proximity of amyloid core domain (NFGAIL) of hIAPP and restrain its structural rearrangement. This study provides a valuable approach to develop polymer-based anti-amyloid inhibitors that may diminish the population of intermediates of A{beta}40 or hIAPP.

biophysics↗