**Background:** Skin wound healing often results in scar formation, which can cause physical and psychological distress. Current treatments are limited, and clinical trials of single growth factors (e.g., TGF-β3, IL-10) have failed to meet endpoints. This study explores a novel approach using human adipose-derived stem cells (hADSCs) as delivery vehicles for modified mRNA (modRNA) encoding TGF-β3 and IL-10 to create a scar-free healing microenvironment.
**Methods:** hADSCs were isolated from liposuction tissue and transfected with m1ψ-modified mRNA encoding TGF-β3 and/or IL-10 using liposomal reagents. Transfection efficiency was assessed by qRT-PCR and ELISA. In vitro, a Transwell coculture system was used to evaluate the effects of modRNA-loaded ADSCs on primary keloid fibroblasts (KFs), assessing proliferation (EdU, CCK-8), migration (scratch and transwell assays), cell cycle (flow cytometry), apoptosis (Annexin V/PI), and ECM-related gene/protein expression (qRT-PCR, Western blot, ELISA). In vivo, 20 male SD rats were divided into 5 groups (n=4/group) with two 1-cm dorsal excisional wounds. On Days 0, 7, and 14, wounds were injected with PBS (control), ADSCs, ADSCs^TGF-β3^, ADSCs^IL-10^, or ADSCs^dual^ (0.7×10^6 cells in 100 μL PBS injected around each wound, plus 0.3×10^6 cells in 20 μL Matrigel topically). Wound closure was photographed on Days 0, 5, 10, 15, and 25. Wounds were harvested on Day 18 for histology (HE, Masson's trichrome, picrosirius red, immunohistochemistry, immunofluorescence). An ex vivo keloid explant model was also used, where keloid biopsies were cultured with conditioned medium from ADSCs, ADSCs^TGF-β3^, ADSCs^IL-10^, or ADSCs^dual^ for 14 days, followed by analysis of collagen content (hydroxyproline assay, Western blot).
**Key Results:** Transfection of modRNA into ADSCs led to efficient and transient protein secretion: TGF-β3 peaked at 18 ng/mL after 48 h and decreased ~50% per day, while IL-10 sustained ~55 ng/mg for 96 h. Co-transfection (ADSCs^dual^) showed higher gene expression and protein translation than single transfections. In vitro, ADSCs^dual^ significantly inhibited KF proliferation (EdU-positive fraction reduced, p<0.001) and migration (transwell assay, p<0.001), and increased apoptosis after heat stress. ADSCs^dual^ upregulated MMP1, MMP8, and MMP12 expression and secretion in KFs (ELISA, p<0.001). ADSCs^IL-10^ and ADSCs^dual^ reduced α-SMA expression and promoted myofibroblast dedifferentiation (immunofluorescence, Western blot). In vivo, all wounds closed by Day 25. ADSCs^IL-10^ showed delayed closure on Day 15 (p<0.05), but ADSCs^dual^ did not. Histology on Day 18 showed that ADSCs^TGF-β3^ and ADSCs^dual^ significantly reduced epidermal thickness, scar index, and collagen volume fraction (Masson's trichrome, p<0.001). Picrosirius red staining revealed improved collagen organization (basket-weave pattern) in modRNA-treated groups. CD31 staining showed increased neovascularization in ADSCs^TGF-β3^ and ADSCs^dual^ groups (p<0.001). α-SMA expression was reduced, and α-SMA-positive cell apoptosis was increased in ADSCs^IL-10^ and ADSCs^dual^ groups (p<0.001). In the ex vivo keloid model, ADSCs^TGF-β3^ and ADSCs^dual^ conditioned medium significantly reduced collagen I and III expression (Western blot, p<0.001) and total hydroxyproline content in tissue (p<0.001), while increasing hydroxyproline release into the medium (p<0.001).
**Clinical Implications:** This study provides the first evidence that mRNA technology can be applied to dermal fibrosis, using ADSCs as a delivery platform for transient, pulsatile expression of TGF-β3 and IL-10. The synergistic effects of this dual therapy improved multiple aspects of wound healing—collagen remodeling, neovascularization, myofibroblast clearance, and ECM degradation—without the safety concerns of viral vectors. While promising, limitations include the use of same-sex rats, focus on pathologic KFs, and the need for further safety and dosing studies. This platform could be developed for scar-susceptible populations, such as those with keloid or hypertrophic scar tendencies.