常用实验动物不同组织部位肥大细胞异质性的组织学特点比较

目的探讨并比较六种常用实验动物不同部位肥大细胞异质性的形态学特点。方法应用麻醉后处死的方法,取小鼠、大鼠、豚鼠、兔、犬和猴的皮肤、肺脏、乙状结肠和脾脏组织,经4%中性缓冲甲醛溶液或Bouin’s液固定后,制作常规组织切片,分别作HE、甲苯胺蓝、阿尔新蓝-藏红和P物质免疫组织化学染色,镜下观察并应用彩色病理图像分析软件进行形态学分析;另取皮肤组织固定于磷酸缓冲戊二醛溶液,制作常规超薄切片,透射电镜下观察肥大细胞超微结构。结果六种动物不同组织中肥大细胞各有其分布特点,且在形态大小、异染性及染色特性等方面表现各异,肥大细胞密度和形态学参数差异有显著性（P〈0.05）;豚鼠、犬和猴皮肤肥大细胞颗粒具有特殊亚微结构;小鼠皮肤组织内可见P物质免疫阳性肥大细胞和神经纤维,犬脾脏内可见P物质免疫阳性肥大细胞。结论在六种实验动物的同一组织中以及同一种动物不同组织中,肥大细胞具有明显的异质性,此异质性对采用实验动物开展与肥大细胞功能相关的动物实验研究具有重要参考价值。     

Comparative skin mucus and serum humoral defence mechanisms in the teleost gilthead seabream (Sparus aurata)

Mucosal surfaces of fish, including skin, gill and gut, contain numerous immune substances poorly studied that act as the first line of defence against a broad spectrum of pathogens. This study aimed to identify and characterize for the first time different constitutive humoral defence mechanisms of the skin mucus of gilthead seabream (Sparus aurata). To do this, the levels of total immunoglobulin M, several enzymes and proteins (peroxidase, lysozyme, alkaline phosphatase, esterases, proteases and antiproteases), as well as the bactericidal activity against opportunist fish pathogens (Vibrio harveyi, Vibrio angillarum, Photobacterium damselae) and non-pathogenic bacteria (Escherichia coli, Bacillus subtilis) were measured in the skin mucus and compared with those found in the serum. This study demonstrates that gilthead seabream skin mucus contains lower levels of IgM, similar levels of lysozyme, alkaline phosphatase and proteases, and higher esterase, peroxidase and antiprotease activities than serum. In addition, skin mucus revealed stronger bactericidal activity against tested fish pathogen bacteria compared to the serum activity, while human bacteria can even grow more in the presence of mucus. The results could be useful for better understanding the role of the skin mucus as a key component of the innate immune system with potential application for the aquaculture.     

微小RNA miR-21在皮肤创伤愈合中的研究进展

微小RNA是一类真核细胞中广泛存在的内源性转录后调控分子,其在细胞的增殖、分化、凋亡、迁移等过程中发挥了重要的调控作用。皮肤创伤修复涉及复杂的细胞与分子的相互作用网络。近年来研究表明micro RNAs在皮肤创伤修复中发挥调控作用,引人关注。miR-21作为重要的癌基因是目前研究的最多的miRNAs分子之一,其在皮肤创伤修复中的作用研究也越来越受到重视。研究表明miR-21参与了细胞增殖与迁移、炎症反应、血管生成和细胞外基质合成等重要修复相关事件的调控。因此,阐明miR-21分子在正常皮肤创伤愈合中的作用,厘清miR-21表达失调在修复不足和修复过度中的功能,将深化我们对于皮肤创伤愈合基本理论的认识,并为促进创面愈合与防治修复不足和过度提供潜在的治疗靶点。本文就miR-21分子在正常皮肤创伤修复、慢性难愈性创面和增生性瘢痕中作用的研究进展进行综述展望。     

Interleukin-36 potently stimulates human M2 macrophages,Langerhans cells and keratinocytes to produce pro-inflammatory cytokines

Interleukin (IL)-36 cytokines belong to the IL-1 family and include three agonists, IL-36 α, β and γ and one inhibitor, IL-36 receptor antagonist (IL-36Ra). IL-36 and IL-1 (α and β) activate similar intracellular pathways via their related heterodimeric receptors, IL-36R/IL-1RAcP and IL-1R1/IL-1RAcP, respectively. However, excessive IL-36 versus IL-1 signaling induces different phenotypes in humans, which may be related to differential expression of their respective receptors.We examined the expression of IL-36R, IL-1R1 and IL-1RAcP mRNA in human peripheral blood, tonsil and skin immune cells by RT-qPCR. Monocyte-derived dendritic cells (MDDC), M0, M1 or M2-polarized macrophages, primary keratinocytes, dermal macrophages and Langerhans cells (LC) were stimulated with IL-1β or IL-36β. Cytokine production was assessed by RT-qPCR and immunoassays.The highest levels of IL-36R mRNA were found in skin-derived keratinocytes, LC, dermal macrophages and dermal CD1a⁺ DC. In the blood and in tonsils, IL-36R mRNA was predominantly found in myeloid cells. By contrast, IL-1R1 mRNA was detected in almost all cell types with higher levels in tonsil and skin compared to peripheral blood immune cells. IL-36β was as potent as IL-1β in stimulating M2 macrophages, keratinocytes and LC, less potent than IL-1β in stimulating M0 macrophages and MDDC, and exerted no effects in M1 and dermal macrophages. Levels of IL-1Ra diminished the ability of M2 macrophages to respond to IL-1.Taken together, these data are consistent with the association of excessive IL-36 signaling with an inflammatory skin phenotype and identify human LC and M2 macrophages as new IL-36 target cells.     

Parasitic mites of medical and veterinary importance – is there a common research agenda?

There are an estimated 0.5–1 million mite species on earth. Among the many mites that are known to affect humans and animals, only a subset are parasitic but these can cause significant disease. We aim here to provide an overview of the most recent work in this field in order to identify common biological features of these parasites and to inform common strategies for future research. There is a critical need for diagnostic tools to allow for better surveillance and for drugs tailored specifically to the respective parasites. Multi-‘omics’ approaches represent a logical and timely strategy to identify the appropriate mite molecules. Recent advances in sequencing technology enable us to generate de novo genome sequence data, even from limited DNA resources. Consequently, the field of mite genomics has recently emerged and will now rapidly expand, which is a particular advantage for parasitic mites that cannot be cultured in vitro. Investigations of the microbiota associated with mites will elucidate the link between parasites and pathogens, and define the role of the mite in transmission and pathogenesis. The databases generated will provide the crucial knowledge essential to design novel diagnostic tools, control measures, prophylaxes, drugs and immunotherapies against the mites and associated secondary infections.     

Hyaluronan Breakdown Contributes to Immune Defense against Group A Streptococcus

Group A Streptococcus (GAS) commonly infects human skin and occasionally causes severe and life-threatening invasive diseases. The hyaluronan (HA) capsule of GAS has been proposed to protect GAS from host defense by mimicking endogenous HA, a large and abundant glycosaminoglycan in the skin. However, HA is degraded during tissue injury, and the functions of short-chain HA that is generated during infection have not been studied. To examine the impact of the molecular mass of HA on GAS infection, we established infection models in vitro and in vivo in which the size of HA was defined by enzymatic digestion or custom synthesis. We discovered that conversion of high molecular mass HA to low molecular mass HA facilitated GAS phagocytosis by macrophages and limited the severity of infection in mice. In contrast, native high molecular mass HA significantly impaired internalization by macrophages and increased GAS survival in murine blood. Thus, our data demonstrate that GAS virulence can be influenced by the size of HA derived from both the bacterium and host and suggest that high molecular mass HA facilitates GAS deep tissue infections, whereas the generation of short-chain HA can be protective.     

Targeting O-Glycosyltransferase (OGT) to Promote Healing of Diabetic Skin Wounds

Non-healing wounds are a significant source of morbidity. This is particularly true for diabetic patients, who tend to develop chronic skin wounds. O-GlcNAc modification of serine and threonine residues is a common regulatory post-translational modification analogous to protein phosphorylation; increased intracellular protein O-GlcNAc modification has been observed in diabetic and hyperglycemic states. Two intracellular enzymes, UDP-N-acetylglucosamine-polypeptide β-N-acetylglucosaminyl transferase (OGT) and O-GlcNAc-selective N-acetyl-β-d-glucosaminidase (OGA), mediate addition and removal, respectively, of N-acetylglucosamine (GlcNAc) from intracellular protein substrates. Alterations in O-GlcNAc modification of intracellular proteins is linked to diabetes, and the increased levels of protein O-GlcNAc modification observed in diabetic tissues may in part explain some of the observed underlying pathophysiology that contributes to delayed wound healing. We have previously shown that increasing protein O-GlcNAc modification by overexpression of OGT in murine keratinocytes results in elevated protein O-GlcNAc modification and a hyperadhesive phenotype. This study was undertaken to explore the hypothesis that increased O-GlcNAc modification of cellular proteins in diabetic skin could contribute to the delayed wound healing observed in patients with diabetic skin ulcers. In the present study, we show that human keratinocytes cultured under hyperglycemic conditions display increased levels of O-GlcNAc modification as well as a delay in the rate of wound closure in vitro. We further show that specific knockdown of OGT by RNA interference (RNAi) reverses this effect, thereby opening up the opportunity for OGT-targeted therapies to promote wound healing in diabetic patients.     

ERK2 dependent signaling contributes to wound healing after a partial-thickness burn

Burn healing is a complex physiological process involving multiple cell activities, such as cell proliferation, migration and differentiation. Although extracellular signal-regulated kinases (ERK) have a pivotal role in regulating a variety of cellular responses, little is known about the individual functions of ERK isoform for healing in vivo. This study investigated the role of ERK2 in burn healing. To assess this, Erk2^+/− mice generated by gene targeting were used. The resultant mice exhibited significant delay in re-epithelization of partial-thickness burns in the skin in comparison to wild-type. An in vitro proliferation assay revealed that keratinocytes from Erk2^+/− mice grew significantly slower than those prepared from wild-type. These results highlight the importance of ERK2 in the process of burn healing.     

Cyanobacteria and microalgae bioactive compounds in skin-ageing: potential to restore extracellular matrix filling and overcome hyperpigmentation

As the largest organ in human body, skin acts as a physicochemical barrier, offering protection against harmful environmental stressors, such as chemicals, pathogens, temperature and radiation. Nonetheless, skins prominence goes further, with a significant psychosocial role in an increasingly ageing population. Prompted by consumers’ concern regarding skincare, cosmetic industry has been developing new formulas capable of lessening the most visible signs of ageing, including reduction in skin density and elasticity, wrinkling and hyperpigmentation. Allied to skincare is the rising importance set on natural products, sustainably obtained from less environmental impacting methods. Cyanobacteria and microalgae are adding importance in this field, given their ability to biosynthesize secondary metabolites with anti-ageing potential. In this review, we present an overview on the potential of cyanobacteria and microalgae compounds to overcome skin-ageing, essentially by exploring their effects on the metalloproteinases collagenase, elastase, gelatinase and hyaluronidase, and in other enzymes involved in the pigmentation process.     

Role of voluntary motor activity on menthol-induced hyperthermia in mice

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This study tested the hypothesis that activating cutaneous TRPM8 receptors by menthol causes an increase in voluntary activity, because of a heat-seeking behavior, that contributes to menthol-induced hyperthermia in mice.