Low-Temperature Fabrication of Thymosin β4-Loaded Soluble Microneedles to Promote Wound Healing by Specific Binding to Downregulated Immune Regulators Vsig4 and IL22rɑ2.
This study developed a novel low-temperature fabrication method for soluble microneedles (MNs) loaded with thymosin β4 (Tβ4), a peptide with known wound-healing and immunomodulatory properties. Traditional MN production methods involve conditions that can denature sensitive peptides, so the researchers used chitosan and sucrose to create stable, biocompatible MNs at lower temperatures. The resulting patches demonstrated uniform morphology, a high drug-loading capacity (~248 µg/patch), and rapid dissolution within one hour. In a mouse wound model, Tβ4-loaded MNs significantly enhanced wound healing compared to controls. To investigate the underlying mechanism, the study employed RNA sequencing and differentially expressed gene (DEG) analysis, identifying downregulated immune regulators Spp1, Vsig4, and IL22rα2 as potentially relevant targets. Subsequent in vitro experiments — including qPCR, western blot, and surface plasmon resonance (SPR) — demonstrated that Tβ4 specifically binds to Vsig4 (KD = 3.56 × 10⁻⁶ M) and IL22rα2 (KD = 9.69 × 10⁻⁶ M). A key limitation is that efficacy and mechanistic data are primarily derived from mouse models and cell-based assays, with no human clinical data reported. The findings offer insights into Tβ4's immunomodulatory targets and potential avenues for drug development.
Why this grade: Wound-healing efficacy was assessed in a mouse model, and mechanistic binding data came from in vitro cell assays and SPR; no human subjects were involved.
Skin wound treatment is hindered by the poor penetration of large therapeutics and a lack of treatments that effectively regulate immune environments. While microneedles (MNs) can bypass the skin, they destabilize sensitive peptides, including thymosin β4 (Tβ4), whose immunomodulatory targets are not well understood, limiting their clinical use. This study introduces a novel fabrication method for Tβ4-loaded soluble MNs at low temperatures using chitosan and sucrose, avoiding the denaturing conditions of traditional MN production. These MNs exhibit a uniform shape, high drug capacity (248.15 ± 1.37 µg/patch), quick dissolution within an hour, excellent biocompatibility, and significantly enhanced wound healing in mice. This study examines the mechanism by which Tβ4 accelerates wound healing, identifying the downregulated immune regulators Spp1, Vsig4, and IL22rɑ2 through RNA-seq and DEG analysis. In vitro qPCR, western blot, and surface plasmon resonance (SPR) experiments demonstrate that Tβ4 specifically binds to the downregulated immune regulators Vsig4 (K D = 3.56 × 10 -6 m) and IL22rɑ2 (K D = 9.69 × 10 -6 m). This article explores how Tβ4 influences the wound immune microenvironment to aid healing, identifies its specific molecular targets, and moves beyond its general roles to offer new opportunities for drug development.
Educational summary of published research — not medical advice. License: cc by-nc-nd. Full text is shown only where licensing permits.