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  • In mammals NETs contain DNA and

    2020-02-05

    In mammals, NETs contain DNA and antimicrobial proteins composed mainly of nuclear histones, granule-derived neutrophil elastase, myeloperoxidase, lactoferrin, pentraxin, and gelatinase among others [11], [46], [47], [48]. In fish, NETs-like structures have been observed, and DNA staining and immunofluorescence assay confirmed the presence of DNA and histones in these structures [11], [28]. However, the molecules that contribute to the antibacterial effect of fish NETs are unclear. In our study, we found that CsH2B, CsH4, CsEla1, and CsEla2 were detected in NETs stimulated by various stimuli, and that the presence of antibodies against either of these proteins significantly increased the survival of the P. fluorescens trapped in NETs. These observations indicate that CsH2B, CsH4, CsEla1, and CsEla2 are the basic constituents of fish NETs and that these proteins play an essential role in the execution of killing NETs-trapped bacteria.
    Acknowledgements This work was supported by the grants from the National Natural Science Foundation of China (41576150 and 31330081), the AoShan Talents Program Supported by Elacridar Qingdao National Laboratory for Marine Science and Technology (No. 2015ASTP), and the Taishan Scholar Program of Shandong Province.
    Introduction Although topical drug delivery is one of the most promising routes of administration, the stratum corneum (SC) is still a major biological barrier that makes it a challenge. Topical formulations are selected due to their localized effects at the site of the application, taking advantage of drug permeation into the deeper layers of skin. However, approximately 40% of the novel promising molecules exhibit low or insignificant solubility, presenting problems often associated with low Elacridar and poor bioavailability [1], [2]. Several formulation strategies have been suggested to overcome these bioavailability problems, including the use of polymeric and lipid-based nanoparticles, to improve percutaneous absorption due to their capacity to enhance the rate and extent of transport across the skin, as a result of their high specific surface area [3], [4], [5], [6]. Nanoparticulate carriers can provide important advantages over the conventional drug delivery systems, namely the possibility to modulate the drug release by modifying some of its characteristics as well as the ability to deliver both hydrophilic and hydrophobic drugs. They carry drugs to the target in a controlled manner, offering further advantages such as reducing the dose frequency, increasing therapeutic control, reducing side effects, and, consequently, improving patient compliance [7]. Particularly, starch-based nanocapsules have attracted increasing interest as a nanobiomaterial for topical drug delivery [4], [8]. These nanoparticulate carriers can enhance topical bioavailability due to their reduced particle size, increasing the rate of absorption, and by forming an occlusive layer on the skin surface that decreases water evaporation and creates wider diffusion channels [3], [9]. Furthermore, starch is a natural polymer with an important role and safe application in the pharmaceutical industry, since it is biodegradable, non-toxic, renewable and sustainable [10]. It also allows simple and green processes for nanocapsule preparation, not requiring the use of hazardous organic solvents, while incorporating a wide range of drugs [8]. The human neutrophil elastase (HNE) is a proteolytic enzyme that plays a central role in several inflammatory diseases. An imbalance between HNE and its endogenous inhibitors lead to severe tissue injuries triggering various disease as for instance rheumatoid arthritis, chronic obstructive pulmonary disease, psoriasis or delayed wound healing [11], [12]. The HNE is present inside the migrating neutrophils in the reticular dermis and dermal papillae, as well as outside the cells in micro-abscesses in psoriatic skin. Hence, psoriatic skin contains low concentrations of specific elastase tissue inhibitor, which results in an excessive in vivo hydrolytic activity of neutrophil elastase released from migrating cells [13].