Messenger RNA (mRNA) vaccines have exhibited promising potential for infectious disease prevention. Although various delivery methods have been explored, the use of electroporation (EP) for the delivery of naked mRNA has received relatively less attention. In this study, we used mouse models to investigate whether naked mRNA vaccine delivery via intramuscular EP (IM-EP) elicits a protective immune response against lethal viral infection. To achieve this, we injected C57BL/6 mice with naked mRNA encoding the SARS-CoV-2 mRNA vaccine via IM-EP and evaluated the resulting immune responses. IM-EP-mediated delivery of the mRNA vaccine induced robust humoral and cellular immune responses, characterized by elevated SARS-CoV-2 receptor-binding domain (RBD)-specific IgG antibodies, enhanced IFN-γ production by CD8⁺ T cells, and upregulated cytokine expression in the muscle and lymph nodes. Using the K18-hACE2 mouse model, we revealed that IM-EP-mediated delivery of the naked mRNA vaccine effectively protected mice from lethal SARS-CoV-2 infection. Overall, our findings suggest that the delivery of naked mRNA via IM-EP can be an effective strategy for preventing infectious diseases.

Chronic pressure ulcers persist within a self-sustaining microenvironment marked by unresolved inflammation, inadequate neovascularization, and excessive extracellular-matrix (ECM) degradation, highlighting the need for injectable bioactive scaffolds that can be delivered precisely to reprogram compromised tissue. The ultra-fine micronized human acellular dermal matrix (UFM-hADM; ∼70 μm) is designed to remain suspendable and pass through narrow-gauge injection, enabling uniform distribution along irregular wound margins and undermined tissue planes where sheet-type matrices may have limited contact and conformability. Here, we evaluated perilesional injection of an UFM-hADM (∼70 μm) as an injectable ECM scaffold in a murine cyclic ischemia–reperfusion pressure-ulcer model. Compared to saline, UFM-hADM accelerated early wound closure and improved quality of healing at Day 7, with enhanced re-epithelialization and dermal regeneration accompanied by increased collagen deposition. Mechanistically, UFM-hADM shifted the wound milieu toward a pro-healing program by attenuating pro-inflammatory cytokines (TNF-α and IL-6) while increasing IL-10, promoting neovascularization and vascular maturation (upregulated VEGF, increased CD31 and α-SMA), and restoring balanced ECM remodeling (elevated COL1A1 and COL3A1 with suppression of MMP1 and MMP3). These coordinated molecular changes opposed inflammatory, protease-rich transcriptional signatures identified in human pressure ulcers through public transcriptomic reanalysis. In addition, exploratory observational use of Ministry of Food and Drug Safety (MFDS)-approved UFM-hADM for pressure ulcers, undertaken with patient consent as part of routine clinician-directed care, suggested acceptable tolerability and a favorable healing course during follow-up. Collectively, these findings provide mechanistic support for the adjunctive clinical use of UFM-hADM as a minimally invasive, human-derived injectable ECM adjunct that may facilitate pressure-ulcer healing through coordinated modulation of immune, vascular, and matrix responses.

Journal of Biomedical and Translational Research