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NCBI's PubMed is a powerful literature retrieval tool widely utilised in many areas including science and regulatory affairs. In regulatory affairs, PubMed searches are employed to identify clinical evidence pertinent to product approval processes. To ensure traceability and reproducibility, a highly structured literature search strategy is advised, as laid out in numerous guidance documents issued by regulatory agencies such as the European Commission and the International Medical Device Regulators Forum. Recently, a new version of PubMed was deployed, including a new user interface and, less visibly, potential changes to search algorithms, which may affect the results delivered by search strings. To unravel potential differences among the legacy and new version of PubMed, head-to-head com - parisons with increasing search complexity were performed. For the new version of PubMed, the user interface was redesigned and allows feature customisation. Importantly, as compared to the legacy version of PubMed, the new PubMed delivered diverging numbers of search hits. Of note, the PubMed inherent result sorting methods produced alternating search hit numbers only in the legacy version. Intriguingly, each version identified literature that was not found by the respective other version, although these publications were considered relevant in the search context. Technically, translation of entered search strings into detailed search strings varied between interfaces. Differences between the legacy (online at least until September 30, 2020) and the new version were found, affecting the traceability, reproducibility, and reliability of PubMed data used for approval processes. [ABSTRACT FROM AUTHOR]

Background: The neuropeptide alpha-melanocyte-stimulating hormone is well known as a mediator of skin pigmentation. More recently, it has been shown that alpha-melanocyte-stimulating hormone also plays pivotal roles in energy homeostasis, sexual function, and inflammation or immunomodulation. Alpha-melanocyte-stimulating hormone exerts its antiinflammatory and immunomodulatory effects by binding to the melanocortin-1 receptor, and since T cells are important effectors during immune responses, we investigated the effects of alpha-melanocyte-stimulating hormone on T cell function. Methodology/Principal Findings: T cells were treated with alpha-melanocyte-stimulating hormone, and subsequently, their phenotype and function was analyzed in a contact allergy as well as a melanoma model. Furthermore, the relevance of alpha-melanocyte-stimulating hormone-mediated signaling for the induction of cytotoxicity was assessed in CD8+ T cells from melanoma patients with functional and nonfunctional melanocortin-1 receptors. Here we demonstrate that the melanocortin-1 receptor is expressed by murine as well as human CD8+ T cells, and we furthermore show that alpha-melanocyte-stimulating hormone/melanocortin-1 receptor-mediated signaling is critical for the induction of cytotoxicity in human and murine CD8+ T cells. Upon adoptive transfer, alpha-melanocyte-stimulating hormone-treated murine CD8+ T cells significantly reduced contact allergy responses in recipient mice. Additionally, the presented data indicate that alpha-melanocyte-stimulating hormone via signaling through a functional melanocortin-1 receptor augmented antitumoral immunity by up-regulating the expression of cytotoxic genes and enhancing the cytolytic activity in tumor-specific CD8+ T cells. Conclusions/Significance: Together, these results point to an important role of alpha-melanocyte-stimulating hormone in MHC class I-restricted cytotoxicity. Therefore, treatment of contact allergies or skin cancer with alpha-melanocyte-stimulating hormone or other more stable agonists of melanocortin-1 receptor might ameliorate disease or improve antitumoral immune responses. [ABSTRACT FROM AUTHOR]

Various glutamate receptors have been described in both keratinocytes and melanocytes.l-Glutamate is the physiological agonist of the glutamate receptor family. The source of this transmitter had not yet been identified. In normal human epidermal keratinocytes (NHEK) and HaCaT-keratinocytes, cell supernatants were sampled in various stages of cell density and thel-glutamate content photometrically determined. The following examination time-points were defined: non-confluent (ca. 33%), subconfluent (ca. 70%) and confluent (90–100%). Thel-glutamate concentration originally in the culture medium was 14.7 mg/l (0.1 mm/l). Thel-glutamate concentration in the cell supernatant increased in NHEK with increasing cell density: non-confluent 39.9 ± 4 mg/l, subconfluent 60.6 ± 15.8 mg/l, confluent 100.7 ± 33.2 mg/l. A linear increase ofl-glutamate concentration was also found for HaCaT cells. The investigations show that keratinocytes are capable of producing and releasingl-glutamate. Thus they are a source ofl-glutamate which acts as a transmitter on epidermal glutamate receptors. [ABSTRACT FROM AUTHOR]

Suppression of collagen synthesis is a major therapeutic goal in the treatment of fibrotic disorders. We show here that alpha-melanocyte-stimulating hormone (alpha-MSH), a neuropeptide well known for its pigment-inducing capacity, modulates collagen synthesis and deposition. Alpha-MSH in vitro suppresses the synthesis of collagen types I, III, and V and down-regulates the secretion of procollagen type I C-terminal peptide (PICP) in human dermal fibroblasts treated with the fibrogenic cytokine transforming growth factor-beta1 (TGF-beta1). Alpha-MSH did not interfere with TGF-beta1 signaling, because TGF-beta1-induced expression of collagen mRNA was not affected, implying a posttranscriptional mechanism. Human dermal fibroblasts in vitro express a high affinity binding site for MSH, which was identified by reverse transcription PCR and immunofluorescence analysis as the melanocortin-1 receptor (MC-1R). Immunohistochemical studies on normal adult human skin confirmed MC-1R expression in distinct dermal fibroblastic cells. The MC-1R on fibroblasts appears to be functionally relevant because alpha-MSH increased the amount of intracellular cAMP, and coincubation with a synthetic peptide corresponding to the human Agouti signaling protein abrogated the inhibition of TGF-beta1-induced PICP secretion by alpha-MSH. To assess the in vivo relevance of these findings, a mouse model was used in which dermal fibrosis was induced by repetitive intracutaneous injections with TGF-beta1. The inductive activity of TGF-beta1 on collagen deposition and the number of dermal cells immunoreactive for vimentin and alpha-smooth muscle actin was significantly suppressed by injection of alpha-MSH. Melanocortins such as alpha-MSH may therefore represent a novel class of modulators with potential usefulness for the treatment of fibrotic disorders.

Ultraviolet light is one of the most crucial environmental factors with regard to its capacity to induce skin cancer, premature aging of the skin, and immunosuppression. Although ultraviolet directly affects the function of epidermal cells, many of these effects are mediated by induction of cytokines, growth factors, and neuropeptides, such as alpha-melanocyte-stimulating hormone. Recently, in addition to its well-known pigmentation inducing activity, a strong anti-inflammatory as well as an immunomodulatory potential of alpha-melanocyte-stimulating hormone has been recognized. The aim of this study was to determine, whether ultraviolet irradiation affects the expression of both alpha-melanocyte-stimulating hormone and the melanocortin-1 receptor in human epidermis in vivo. The volar aspects of the forearms were exposed to twice the minimal erythema dose of solar-simulating radiation. Three, 6, and 24 h after irradiation, the proopiomelanocortin and interleukin-10 mRNA levels in suction blister induced epidermal sheets were considerably upregulated as detected by semiquantitative reverse transcription-polymerase chain reaction. Furthermore, alpha-melanocyte-stimulating hormone and interleukin-10 protein levels in blister fluids were significantly increased 24 h after ultraviolet irradiation, an effect that could be abolished by application of the broad-spectrum sunscreen Anthélios XL prior to ultraviolet (solar-simulating radiation) exposure. In addition, enhanced melanocortin-1 receptor mRNA and receptor protein expression upon solar-simulating radiation was ascertained by reverse transcription-polymerase chain reaction and immunohistochemistry of the epidermal sheets, respectively. Proopiomelanocortin-derived neuropeptides, such as alpha-melanocyte-stimulating hormone may therefore play an important part in modulating ultraviolet-induced inflammation.

Alpha-melanocyte-stimulating hormone (alpha-MSH) is a neuropeptide controlling melanogenesis in pigmentary cells. In addition, its potent immunomodulatory and immunosuppressive activity has been recently described in cutaneous inflammatory disorders. Whether alpha-MSH is also produced in the lung and might play a role in the pathogenesis of inflammatory lung conditions, including allergic bronchial asthma, is unknown. Production and functional role of alpha-MSH were investigated in a murine model of allergic airway inflammation. alpha-MSH production was detected in bronchoalveolar lavage fluids. Although aerosol challenges stimulate alpha-MSH production in nonsensitized mice, this rapid and marked stimulation was absent in allergic animals. Treatment of allergic mice with alpha-MSH resulted in suppression of airway inflammation. These effects were mediated via IL-10 production, because IL-10 knockout mice were resistant to alpha-MSH treatment. This study provides evidence for a novel function of alpha-MSH linking neuroimmune functions in allergic airway inflammation.

There is a substantial body of evidence that the tridecapeptide alpha-melanocyte-stimulating hormone (alpha-MSH) functions as a mediator of immunity and inflammation. The immunomodulating capacity of alpha-MSH is primarily because of its effects on melanocortin receptor (MC-1R)-expressing monocytes, macrophages, and dendritic cells (DCs). alpha-MSH down-regulates the production of proinflammatory and immunomodulating cytokines (IL-1, IL-6, TNF-alpha, IL-2, IFN-gamma, IL-4, IL-13) as well as the expression of costimulatory molecules (CD86, CD40, ICAM-1) on antigen-presenting DCs. In contrast, the production of the cytokine synthesis inhibitor IL-10 is up-regulated by alpha-MSH. At the molecular level, these effects of alpha-MSH are mediated via the inhibition of the activation of transcription factors such as NFkappaB. Not only alpha-MSH but also its C-terminal tripeptide (alpha-MSH 11-13, KPV) was able to bind to MC-1R and to modulate the function of APCs. In vivo, using a mouse model of contact hypersensitivity (CHS) systemic and topical application of alpha-MSH or KPV inhibited the sensitization and the elicitation phase of CHS and was able to induce hapten-specific tolerance. To investigate the underlying mechanisms of tolerance induction, we have performed in vivo transfer experiments. Treatment of naive mice with bone marrow-derived immature haptenized and alpha-MSH-pulsed DCs resulted in a significant inhibition of CHS. Furthermore, tolerance induction was found to be mediated by the generation of CTLA4(+) and IL-10-producing T lymphocytes. The potent capacity of alpha-MSH to modulate the function of antigen-presenting cells (APCs) has been further supported in another experimental approach. In vitro, by activating APCs, alpha-MSH has been shown to modulate IgE production by IL-4 and anti-CD40 stimulated B lymphocytes. Moreover, in a murine model of allergic airway inflammation, systemic treatment with alpha-MSH resulted in a significant reduction of allergen-specific IgE production, eosinophil influx, and IL-4 production. These effects were mediated via IL-10 production, because IL-10 knockout mice were resistant to alpha-MSH treatment. Therefore, therapeutic application of alpha-MSH or related peptides (KPVs) as well as alpha-MSH/KPV-pulsed DCs may be a useful approach for the treatment of inflammatory, autoimmune, and allergic diseases in the future.

Proteinase-activated receptor 2 belongs to a new G protein-coupled receptor subfamily activated by various serine proteases. It has been demonstrated to play a role during inflammation of many tissues including the skin. Proteinase-activated receptor 2 is expressed by endothelial cells and regulates cutaneous inflammation in vivo. The underlying mechanisms of proteinase-activated receptor 2 activation in the skin and the effects on human dermal microvascular endothelial cells, however, are still unknown. Agonists of proteinase-activated receptor 2 such as mast cell tryptase induce widespread inflammation in many organs including the skin. Trypsinogen is generated by endothelial cells during inflammation or tumor growth. Therefore we tested whether human dermal microvascular endothelial cells express functional proteinase-activated receptor 2 and whether agonists of proteinase-activated receptor 2 regulate inflammatory responses in these cells. Calcium mobilization studies revealed that proteinase-activated receptor 2 is functional in human dermal microvascular endothelial cells. Interleukin-6 and interleukin-8 were upregulated as detected by reverse transcription polymerase chain reaction or enzyme-linked immunosorbent assay indicating a role of proteinase-activated receptor 2 in stimulating human dermal microvascular endothelial cells. Electromobility shift assays revealed proteinase-activated-receptor-2-induced activation of nuclear transcription factor kappaB with a maximum after 1 h. In conclusion, agonists of proteinase-activated receptor 2 upregulate interleukin-6 and interleukin-8 expression and release in human dermal microvascular endothelial cells. Thus, proteinase-activated receptor 2 may play an important role in cutaneous inflammation by mediating inflammatory responses on dermal microvascular endothelial cells and activation of nuclear transcription factor kappaB.