[Preparation of recombinant mussel mucin Mfp-3P and its promotion of wound healing].

To investigate the role of recombinant mussel mucin in wound healing, we aimed to prepare this mucin using Pichia pastoris as the host microbe. Our method involved constructing a genetically engineered strain of P. pastoris that expressed a fusion protein consisting of Mfp-3 and preCol-P peptide segments of mussel. After fermentation and purification, we obtained a pure recombinant mussel mucin product. We then conducted experiments to evaluate its effect at both the cellular and animal levels. At the cellular level, we examined its impact on the proliferation and migration of mouse fibroblast L929. At the animal level, we assessed its ability to promote wound healing after full-layer skin resection in rats. Our results showed that the recombinant mussel mucin protein has a content of 90.28% and a purity of 96.49%. The content of 3,4-dihydroxyphenylalanine (DOPA) was 0.73 wt%, and the endotoxin content was less than 0.5 EU/mg. Importantly, the recombinant mussel mucin protein significantly promoted both the migration and proliferation of mouse fibroblast, as well as the wound healing in rat skin. In conclusion, our findings demonstrate that recombinant mussel mucin has the potential to promote wound healing and can be considered a promising medical biomaterial.

Assessment of biological properties of recombinant collagen-hyaluronic acid composite scaffolds.

OBJECTIVE: Recombinant collagen (rCOL)-hyaluronic acid (HA) composite scaffolds were prepared to thoroughly investigate their biological properties. METHODS: The rCOL and HA composite scaffolds were formulated via lyophilization. The scaffolds were characterized for various materials properties, including porosity, surface modification, and degradation rates. Biological properties such as in vitro cytotoxicity, cell adhesion, proliferation and migration effects were also evaluated. RESULTS: The water absorption, mechanical strength, degradation resistance and thermal stability of the prepared rCOL-HA composites were improved over that of the control studied. Scanning electron microscopy (SEM) revealed that the composites formed a three-dimensional network structure with uniform pore distribution. The cytotoxicity of the composites was minimal (grade I) and the material showed strong adhesion and proliferation effects when grown with mouse fibroblasts, particularly the composite material of rCOL (5% HA) group (P < 0.05). CONCLUSION: The rCOL-HA composite prepared via lyophilization after cross-linking is characterized by high porosity, high water absorption, and good interaction between the material and cells, as well as good biodegradability. Compared with rCOL materials, rCOL-HA has increased mechanical strength, water absorption and thermal stability. The biocompatibility and fibroblast proliferation of rCOL-HA have excellent biological performance, providing a new material for wound healing applications.

[Preparation and characterization of recombinant human-source collagen].

This study aimed to obtain a recombinant human-source collagen for industrialization. First, based on the Gly-X-Y sequence of human type I collagen, we optimized the hydrophilic Gly-X-Y collagen peptide, designed the human collagen amino acid sequence and the corresponding nucleotide sequence. Next, the expression vector pPIC9K-COL was constructed via endonuclease digestion technology. We obtained an engineering strain of human-source collagen by electrotransforming Pichia pastoris, and then it was fermented, purified and identified. As a result, the expression level reached 4.5 g/L and the purity was over 95%. After amino acid N-terminal sequencing, molecular weight analysis, amino acid analysis and collagenase degradation test, we confirmed that the obtained collagen was consistent with designed primary structure of human-source collagen. After freeze-drying, we analyzed the collagen by scanning electron microscope and cell cytotoxicity, confirming that the collagen has porous fiber reticular structure and superior cytocompatibility. This indicates that human-source collagen has potential to be applied as biomedical material. In conclusion, we successfully obtained the expected human-source collagen and laid a foundation to its further application.

[Transcriptional expression of GPR43 gene in adipose tissue and primary cultured adipocytes of pig].

GPR43 (G protein-coupled receptor 43) is a recently discovered short-chain free fatty acid receptor which plays important role in adipogenesis. Here we explored the transcriptional expression rule of GPR43 in porcine adipose tissue and primary cultured adipocytes. Partial cDNA of GPR43 was successfully cloned from swine by RT-PCR and the expression profile of GPR43 mRNA was studied from different types, different growing stages, and different sites of porcine adipose tissue as well as porcine primary cultured adipocytes. The results showed that porcine GPR43 shared high homology with human (89%), mouse (84%) and rat (83%). The expression level of GPR43 mRNA was significantly higher in adipose tissue of obese pigs than that of lean pigs, and also the expression level gradually increased with age. Further, the abundance of GPR43 mRNA level was higher in subcutaneous fat than in visceral fat. In addition, during the adipocytes differentiation, the expression of GPR43 mRNA increased in a time-dependent manner. These data indicated that GPR43 gene expression was relate to the site of adipose tissue, economic type, and age of pig as well as differentiating state of adipocytes, implying that GPR43 can be a potential factor to regulate adipogenesis.