Développement analytique et caractérisation in vitro de nanoparticules fonctionnalisées ciblant l'agrégation de hIAPP dans le diabète de type 2
Year: 2025
Type: dissertation
Abstract: Type 2 diabetes (T2D) remains one of the most pressing global health challenges, characterized by chronic hyperglycemia and progressive pancreatic β-cell degeneration. A key pathogenic hallmark is the extracellular aggregation of human islet amyloid polypeptide (hIAPP), leading to the formation of toxic oligomers and amyloid fibrils that compromise β-cell viability and accelerate functional decline. Despite the magnitude of the problem, current therapeutic options are limited to symptomatic management, with no curative treatment available. This underscores the urgent need for innovative approaches that intervene at the earliest stages of hIAPP aggregation. Within this context, nanomedicine provides a highly promising framework.This thesis, conducted within an ANR project, introduces an original strategy based on anisotropic Janus nanorods (JNRs) specifically engineered to capture hIAPP and prevent its progression into cytotoxic species. These nanorods, generated through polymer co-assembly, exhibit a unique bifacial architecture: one face is functionalized with a selective hIAPP-binding ligand, while the opposite surface remains available for interactions with blood circulating proteins. Extensive physicochemical characterization revealed cylindrical morphologies (100-1000 nm in length, ~10 nm in diameter) and excellent colloidal stability.To investigate their biological interface, interactions between JNRs and plasma proteins, particularly human serum albumin (HSA), were quantified using frontal analysis continuous capillary electrophoresis (FACCE), a label-free, quantitative method further developed and optimized in this work. Binding constants revealed weak interactions, providing critical insight into JNR and HSA interactions and its potential impact on nanoparticle biodistribution.Functionalization of JNRs with a β-helical ligand, referred to as LP2, yielded strong and highly specific binding to hIAPP (~10⁶ M⁻¹), as quantified by an optimized FACCE method. Importantly, JNR-LP2 demonstrated a strong capacity to inhibit hIAPP oligomerization and fibrillation, as confirmed by capillary zone electrophoresis (CZE) and thioflavin T fluorescence assays, respectively. In vitro studies on pancreatic β-cells established both the biocompatibility of JNR-LP2 and their protective effect against hIAPP-induced cytotoxicity, most likely through selective sequestration of toxic oligomeric species.Collectively, these findings shed light on the therapeutic potential of JNR-LP2 in T2D. Beyond demonstrating efficacy, this work highlights the value of orthogonal analytical approaches to thoroughly characterizing complex anisotropic nanomaterials and elucidating key parameters governing their biological interactions. Future in vivo investigations will be essential to assess the influence of protein interactions on biodistribution and to unravel the molecular mechanisms underlying hIAPP aggregation inhibition.
Source: theses.fr (ABES)
Author: Jégo, Mathilde
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7108844266
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