Localized delivery of curcumin by thermosensitive hydrogels for promoting wound healing.

BACKGROUND: Curcumin can promote wound healing, but its drug delivery medium needs to be improved further. OBJECTIVES: A curcumin-loaded thermosensitive hydrogel was prepared, its characterization was evaluated, and its promoting effect on wound healing was observed. METHODS: Curcumin-loaded thermosensitive hydrogels were prepared with different percentages of poloxamer 188 and poloxamer 407. A small tube inversion assay was used to observe the sol-gel transition temperature, and a rotational rheometer was used to detect the sol viscosity, sol-gel phase transition temperature, and phase transition time. The microstructure of the gel was observed by scanning electron microscopy, and Fourier infrared spectroscopy was used to evaluate whether curcumin was successfully loaded. Finally, its promoting effect on wound healing was observed in vivo and in vitro. RESULTS: Poloxamer 407 24% and poloxamer 188 1% were selected to prepare curcumin-loaded thermosensitive hydrogels. After 60 ± 15 s at 32°C, the sol-gel transition process was completed, with certain elastic behavior and solid-like rheological properties. Scanning electron microscopy showed that the pores of the curcumin-P407/P188 thermosensitive hydrogel were interconnected, with an average pore size ranging from 5 to 10 µm. Hydrogels showed a higher swelling ratio. Fourier transform infrared spectroscopy showed that curcumin had been incorporated into the hydrogel. Live/dead cell assays suggested that the hydrogel was not toxic to fibroblasts. Curcumin-loaded thermosensitive hydrogels can promote an increase in S-phase fibroblasts and improve wound healing. CONCLUSIONS: Curcumin-loaded P407/P188 thermosensitive hydrogel improves wound healing. More in-depth research is needed in the future.

Role of miRNAs in melanin metabolism: Implications in melanin-related diseases.

BACKGROUND: MicroRNAs (miRNAs) are short single-stranded non-coding RNAs that regulate degradation and expression of messenger RNA (mRNA) and play a wide range of key roles in different biological processes. They mediate different stages of melanocyte differentiation, growth, and apoptosis through a variety of pathways and can mediate melanin production by targeting key enzymes. AIMS: This article was aimed to review the role of miRNAs in melanin metabolism and to introduce the role and significance of miRNAs in melanin-related diseases. MATERIALS & METHODS: Systematic search and retrospective review were performed on the published data. RESULTS: This paper reviews the process of melanin synthesis and the regulatory mechanism, explores the miRNA expression profiles in different model organisms, and introduces the mechanisms of several key miRNAs participating in melanin metabolism through target genes. We also explore the potential role of miRNA as a new target for the treatment of melanin metabolism disease, including vitiligo, melanoma, and chloasma. CONCLUSION: miRNAs play a key role in melanin-related diseases, and the miRNAs involved may be potential therapeutic targets.

The Ubiquitin Proteasome System and Skin Fibrosis.

The ubiquitin proteasome system (UPS) is a highly conserved way to regulate protein turnover in cells. The UPS hydrolyzes and destroys variant or misfolded proteins and finely regulates proteins involved in differentiation, apoptosis, and other biological processes. This system is a key regulatory factor in the proliferation, differentiation, and collagen secretion of skin fibroblasts. E3 ubiquitin protein ligases Parkin and NEDD4 regulate multiple signaling pathways in keloid. Tumor necrosis factor (TNF) receptor-associated factor 4 (TRAF4) binding with deubiquitinase USP10 can induce p53 destabilization and promote keloid-derived fibroblast proliferation. The UPS participates in the occurrence and development of hypertrophic scars by regulating the transforming growth factor (TGF)-ß/Smad signaling pathway. An initial study suggests that TNFα-induced protein 3 (TNFAIP3) polymorphisms may be significantly associated with scleroderma susceptibility in individuals of Caucasian descent. Sumoylation and multiple ubiquitin ligases, including Smurfs, UFD2, and KLHL42, play vital roles in scleroderma by targeting the TGF-ß/Smad signaling pathway. In the future, drugs targeting E3 ligases and deubiquitinating enzymes have great potential for the treatment of skin fibrosis.