Biology subjects

Michalaki, E.

Publications and source records attributed to Michalaki, E..

3 recordsLinked to original sources

bioRxiv2025

A piezoelectric electroporator (Piezopen) for enhanced ''naked'' RNA vaccine delivery

Despite the success of COVID-19 mRNA vaccines, they still face challenges with high costs, complex manufacturing, off-target biodistribution, and systemic reactogenicity stemming from their inflammatory carriers: lipid nanoparticles (LNPs). While "naked" RNA delivery could in principle solve these issues, studies have suggested that it is infeasible due to rapid degradation by RNases and poor cellular entry, thereby necessitating formulations that enhance intracellular delivery and RNA stability. Now, we challenge this paradigm by showing that a simple and inexpensive (<$1), lighter-derived electroporator with microneedle electrodes (Piezopen) can augment gene expression and immunogenicity to naked mRNA leading to comparable responses to LNPs at low doses. We achieve robust responses in the absence of systemic inflammation and reactogenicity using skin-targeted delivery, administer diverse construct types (i.e., mRNA, self-amplifying RNA (saRNA), circular RNA (circRNA)), and demonstrate cross-species validation in live human skin to derisk subsequent clinical application. Our results introduce Piezopen as an inexpensive, well-tolerated, and efficacious alternative to LNPs for mRNA vaccine delivery, designed to facilitate routine vaccinations and pandemic response.

bioengineering↗

bioRxiv2024

Lymphatic endothelial cell-targeting lipid nanoparticles delivering VEGFC mRNA improve lymphatic function after injury

Dysfunction of the lymphatic system following injury, disease, or cancer treatment can lead to lymphedema, a debilitating condition with no cure. Advances in targeted therapy have shown promise for treating diseases where conventional therapies have been ineffective and lymphatic vessels have recently emerged as a new therapeutic target. Lipid nanoparticles (LNPs) have emerged as a promising strategy for tissue specific delivery of nucleic acids. Currently, there are no approaches to target LNPs to lymphatic endothelial cells, although it is well established that intradermal (ID) injection of nanoparticles will drain to lymphatics with remarkable efficiency. To design an LNP that would effectively deliver mRNA to LEC after ID delivery, we screened a library of 150 LNPs loaded with a reporter mRNA, for both self-assembly and delivery in vivo to lymphatic endothelial cells (LECs). We identified and validated several LNP formulations optimized for high LEC uptake when administered ID and compared their efficacy for delivery of functional mRNA with that of free mRNA and mRNA delivered with a commercially available MC3-based LNP (Onpattro). The lead LEC-specific LNP was then loaded with VEGFC mRNA to test the therapeutic advantage of the LEC-specific LNP (namely, LNP7) for treating a mouse tail lymphatic injury model. A single dose of VEGFC mRNA delivered via LNP7 resulted in enhanced LEC proliferation at the site of injury, and an increase in lymphatic function up to 14-days post-surgery. Our results suggest a therapeutic potential of VEGFC mRNA lymphatic-specific targeted delivery in alleviating lymphatic dysfunction observed during lymphatic injury and could provide a promising approach for targeted, transient lymphangiogenic therapy. One Sentence SummaryDevelopment of a novel lymphatic endothelial cell-targeting lipid nanoparticle via in vivo screening for mRNA delivery improves lymphatic regeneration and function after injury.

bioengineering↗

bioRxiv2020

Effect of human synovial fluid from osteoarthritis patients and healthy individuals on lymphatic contractility

The lymphatic system has been proposed to play a crucial role in the development and progression of osteoarthritis (OA). The synovial fluid (SF) of arthritic joints contains mediators of the inflammatory response and products of the injury to articular tissues, while lymphatic system plays a critical role in resolving inflammation and overall joint homeostasis. Despite the importance of both the lymphatic system and SF in OA disease, their relationship is still poorly understood. Here, we utilized SF derived from osteoarthritis patients (OASF) and healthy individuals (HSF) to investigate potential effects of SF on migration of lymphatic endothelial cells (LECs) in vitro, and lymphatic contractility of femoral lymphatic vessels (LVs) ex vivo. Both OASF and HSF treatments led to an increased migratory response in vitro compared to LECs treatment with media without serum. Ex vivo, both OASF and HSF treatments to the lumen of isolated LVs led to significant differences in the tonic and phasic contractions and these observations were dependent on the SF treatment time. Specifically, OASF treatment transiently enhanced the RFLVs tonic contractions. Regarding the phasic contractions, OASF generated either an abrupt reduction after 1 hr of treatment or a complete cease of contractions after an overnight treatment, while HSF treatment displayed a gradual decrease in lymphatic contractility. The observed variations after SF treatments suggest that the pump function of lymphatic vessel draining the joint could be directly compromised in OA and thus might present a new therapeutic target.

bioengineering↗