Loste, A. | Search bioRxiv

bioRxiv2023

Multi-modal profiling of biostabilized human skin modules reveals a coordinated ecosystem response to injected mRNA-1273 COVID-19 vaccine.

The field of vaccination is witnessing a remarkable surge in the development of innovative strategies. There is a need to develop technological platforms capable of generating human data prior to progressing to clinical trials. Here we introduce VaxSkin, a flexible solution designed for the comprehensive monitoring of the natural human skin ecosystems response to vaccines over time. Based on bioengineering to repurpose surgical resections, it allows a comprehensive analysis of the response to vaccines at both organ and single-cell levels. Upon injection of the mRNA-1273 COVID-19 vaccine, we characterized precise sequential molecular events triggered upon detection of the exogenous substance. We also found that the vaccine consistently targets DC/macrophages and mast cells, regardless of the administration route, while promoting specific cell-cell communications in surrounding immune cell subsets. Given its direct translational relevance, VaxSkin provides a multiscale vision of skin vaccination that could pave the way toward the development of new vaccination development strategies.

bioengineering↗

bioRxiv2022

Involvement of an IgE/Mast cell/B cell amplification loop in abdominal aortic aneurysm progression

AimsIgE type immunoglobulins and their specific effector cells, mast cells (MCs), are associated with abdominal aortic aneurysm (AAA) progression. In parallel, immunoglobulin-producing B cells, organised in tertiary lymphoid organs (TLOs) within the aortic wall, have also been linked to aneurysmal progression. We aimed at investigating the potential role and mechanism linking local MCs, TLO B cells, and IgE production in aneurysmal progression. Methods and ResultsThrough histological assays conducted on human surgical samples from AAA patients, we uncovered that activated MCs were enriched at sites of unhealed haematomas, due to subclinical aortic wall fissuring, in close proximity to adventitial IgE+ TLO B cells. Remarkably, in vitro the IgEs deriving from these samples enhanced MC production of IL-4, a cytokine which favors IgE class-switching and production by B cells. Finally, the role of MCs in aneurysmal progression was further analysed in vivo in ApoE-/- mice subjected to angiotensin II infusion aneurysm model, through MC-specific depletion after the establishment of dissecting aneurysms. MC-specific depletion improved intramural haematoma healing and reduced aneurysmal progression. ConclusionsOur data suggest that MC located close to aortic wall fissures are activated by adventitial TLO B cell-produced IgEs and participate to their own activation by providing support for further IgE synthesis through IL-4 production. By preventing prompt repair of aortic subclinical fissures, such a runaway MC activation loop could precipitate aneurysmal progression, suggesting that MC-targeting treatments may represent an interesting adjunctive therapy for reducing AAA progression.

pathology↗