α-MSH inhibits TNF-α-induced maturation of human dendritic cells in vitro through the up-regulation of ANXA1

Potential regulatory mechanism of TNF-α/TNFR1/ANXA1 in glioma cells and its role in glioma cell proliferation

The purpose of this study was to explore the regulatory mechanism of Annexin A1 (ANXA1) in glioma cells in the inflammatory microenvironment induced by tumour necrosis factor α (TNF-α) and its effects on glioma cell proliferation. CCK-8 analysis demonstrated that TNF-α stimulation promotes rapid growth in glioma cells. Changes in tumour necrosis factor receptor 1 (TNFR1) and ANXA1 expression in glioma cells stimulated with TNF-α were revealed through western blot analysis and immunofluorescence staining. Coimmunoprecipitation analysis revealed that ANXA1 interacts with TNFR1. Moreover, we found that ANXA1 promotes glioma cell growth by activating the p65 and Akt signalling pathways. Finally, immunohistochemistry analysis showed an obvious correlation between ANXA1 expression and Ki-67 in glioma tissues. In summary, our results indicate that the TNF-α/TNFR1/ANXA1 axis regulates the proliferation of glioma cells and that ANXA1 plays a regulatory role in the inflammatory microenvironment.

Antifibrotic and Anti-Inflammatory Actions of α-Melanocytic Hormone: New Roles for an Old Player

The melanocortin system encompasses melanocortin peptides, five receptors, and two endogenous antagonists. Besides pigmentary effects generated by α-Melanocytic Hormone (α-MSH), new physiologic roles in sexual activity, exocrine secretion, energy homeostasis, as well as immunomodulatory actions, exerted by melanocortins, have been described recently. Among the most common and burdensome consequences of chronic inflammation is the development of fibrosis. Depending on the regenerative capacity of the affected tissue and the quality of the inflammatory response, the outcome is not always perfect, with the development of some fibrosis. Despite the heterogeneous etiology and clinical presentations, fibrosis in many pathological states follows the same path of activation or migration of fibroblasts, and the differentiation of fibroblasts to myofibroblasts, which produce collagen and α-SMA in fibrosing tissue. The melanocortin agonists might have favorable effects on the trajectories leading from tissue injury to inflammation, from inflammation to fibrosis, and from fibrosis to organ dysfunction. In this review we briefly summarized the data on structure, receptor signaling, and anti-inflammatory and anti-fibrotic properties of α-MSH and proposed that α-MSH analogues might be promising future therapeutic candidates for inflammatory and fibrotic diseases, regarding their favorable safety profile.

Annexin A1 involved in the regulation of inflammation and cell signaling pathways

With the deepening of research, proteomics has developed into a science covering the study of all the structural and functional characteristics of proteins and the dynamic change rules. The essence of various biological activities is revealed from the perspectives of the biological structure, functional activity and corresponding regulatory mechanism of proteins by proteomics. Among them, phospholipid-binding protein is one of the hotspots of proteomics, especially annexin A1, which is widely present in various tissues and cells of the body. It has the capability of binding to phospholipid membranes reversibly in a calcium ion dependent manner. In order to provide possible research ideas for researchers, who are interested in this protein, the biological effects of annexin A1, such as inflammatory regulation, cell signal transduction, cell proliferation, differentiation and apoptosis are described in this paper.

The tripeptide KdPT ameliorates ongoing psoriasis-like skin inflammation in murine and human skin

Psoriasis is a chronic inflammatory disease appearing as scaly erythematous cutaneous lesions, which are characterized by parakeratosis and acanthosis as well as the infiltration of immune cells, such as T helper-1 and T helper-17 cells. Here, we demonstrated that KdPT, a tripeptide structurally related to the C-terminal amino acids of alpha-melanocyte-stimulating hormone, which was previously shown to exhibit anti-inflammatory effects in intestinal inflammation, ameliorated ongoing disease in the mouse model of imiquimod-induced psoriasis-like skin inflammation and in the small xenotransplant mouse model of psoriasis. We could show that systemic KdPT treatment significantly reduced hyperkeratosis and acanthosis in murine as well as human skin. Moreover, KdPT upregulated Foxp3 in CD4⁺ T cells from mice and from peripheral blood of individuals with psoriasis and decreased the expression of type 1 inflammatory cytokines, indicating that the beneficial effect of KdPT was, at least in part, mediated by the induction of functional regulatory T cells that suppressed the activation of pathogenic CD4⁺ IFN-γ⁺ and CD4⁺ IL-17⁺ T cells. Thus, these data might suggest KdPT as a potential novel therapeutic alternative for the treatment of psoriasis.