In recent years, cell penetrating peptides as drug delivery carriers have aroused great interest of scientists, which may help to develop new therapeutic preparations or cosmetics. Generally, compounds with molecular weight greater than 500 Da can hardly penetrate the biofilm. In a recent study report, researchers have covalently combined a sequence promoting wound healing with cell penetrating peptides In order to improve the transport efficiency of drugs in the cell membrane, in the study of cell internalization, the researchers found that the new peptide absorbed by cells can be conjugated into keratinocytes, which can significantly improve the transport of drugs under good tolerance.

In this study, the researchers analyzed the effect of a new type of polypeptide chimera (tylotoin-sc18 ) on wound healing. The results showed that the fusion of polypeptide and (tylotoin) did not induce the loss of its activity. In addition, the researchers also observed the effect of its proliferation on keratinocytes, which may be an important step in wound healing. Tylotoin-sc18 It has strong antibacterial activity and can effectively inhibit bacterial infection in the wound. Due to its multiple functions, researchers speculate whether this new peptide chimera can be used to treat wound infection of the body. Relevant research results are published in the international journal scientific reports.

The skin injury caused by burn or disease often needs effective wound treatment, while the transport of therapeutic and active molecules through the skin has attracted great attention of scientists, and the impermeability of skin cell membrane is often an insurmountable obstacle. Therefore, in the past 10 years, scientists have found cell penetrating polypeptide molecules CPPs may be a new method to transport large molecules across biofilm.

CPPs has a relatively short molecular structure, which is composed of less than 40 amino acid molecules with positive charge. These sequences can carry electrostatic or covalently bound bioactive substances, including plasmid DNA, siRNA and therapeutic proteins, through the cell membrane. In this case, the mechanism of endocytosis may include the process of endocytosis and the process of direct transposition through pores. However, at present Researchers are not clear about the factors and mechanisms that induce molecular transport.

In recent years, scientists have used CPPs as a new transdermal drug delivery system to provide a safe alternative for the cosmetics industry. For example, in the treatment of inflammatory skin diseases, cyclosporine a plant can adsorb on polyargine-7 to form R7 CSA. Until recently, researchers combined the four structural categories of CPPs with human epidermal growth factor (HGF) The fusion protein is used as a wound healing agent.

In this study, horn and his colleagues successfully combined sc18, a peptide with cell permeability characteristics, with tyrotonin, a peptide sequence for wound healing, in tyrottriton The short peptide tylotoin was identified and isolated from the skin of verrucosus); then the researchers evaluated the toxic effect of the conjugate on diagonal protein cells and cancer cell lines to observe the internalization behavior of cells and the effect of these peptides on wound healing in vitro.

Subsequently, the researchers synthesized chimeric peptides containing tyrotoin and CPP sc18. In this study, a shortened version of sc18 was also included. The C-terminal sc18 * lacked four amino acids, and CPP could fuse the C or N-terminal to tyrotoin to form four peptide chimeras. The researchers also used circular dichroism technology to determine the secondary structure of this peptide. In order to eliminate the toxic effect of this potential wound healing agent, the researchers investigated the activity of this peptide in human immortalized keratinocytes (HaCaT). The results showed that tyrotoin-sc18 *, tyrotoin and sc18 keratinocytes had no toxic effect. In subsequent experiments, the researchers used a type of cell called giant unilamellar In this study, the researchers found that the new peptides do not accumulate significantly on the membrane of neutral GUVs. In contrast, when the fluorescent labeled proteins are used to incubate the anionic GUVs, tyrotoin-sc18 * and anion The interaction of ionic lipid membrane will lead to the release of dye to completely dye the whole vesicle.

In order to detect the effect of tyrotoin-sc18 * on wound healing, the researchers conducted a scratch wound healing analysis We also observed the migration of keratinocytes. When tyrotoin-sc18 * was present, the migration of keratinocytes to the wound area increased significantly by 30 hours. In addition, we also observed similar results in human epidermal growth factor (HGF). The new chimeric peptides developed by the researchers have the same migration efficiency as tyrotoin and HGF.

In addition, the researchers analyzed the behavior of the new peptide conjugate in HeLa cells to understand its effect on cancer cell lines. Compared with the control peptide, CF labeled Tylotoin-sC18* The results also showed that the activity of cancer cells induced by tyrotoin-sc18 * decreased, and even at a lower concentration, the potential antitumor activity of this peptide could be indicated.

In this study, the researchers evaluated the inhibition of cytosolic action and the effect of absorption of tyrotonin-sc18 * by HaCaT cells. In order to establish the inhibition conditions of cytosolic action and limit the energy-dependent pathway, HaCaT cells were incubated with tyrotonin-sc18 * at 4 degrees, although the researchers observed the ability of peptides to enter the cells, and at the same time, they could stably locate them in the nucleus, Thus, the hypothesis that peptide chimeras can be directly internalized by translocation is established.

In addition, the fusion of tyrotoin and sc18 * does not damage the intrinsic wound healing ability of tyrotoin. As the researchers have observed, chimeric peptides can increase the healing ability of wound surface in vitro by inducing the migration and proliferation of keratinocytes. When combined with antibacterial properties, this new cell permeable chimeric peptide, tyrotoin sc18 *, can be used as a new type of local peptide Preparation to treat infected wounds.

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