Interleukin-15 inhibits sodium nitroprusside-induced apoptosis of synovial fibroblasts and vascular endothelial cells

Synovial fibroblasts in juvenile idiopathic arthritis: A scoping review

Synovial fibroblasts and their role in juvenile idiopathic arthritis have received limited attention compared to other immune mediated disease such as rheumatoid arthritis. Furthermore, no review exists regarding synovial fibroblasts, their interaction with immune cells and their potential involvement in juvenile idiopathic arthritis pathogenesis. This scoping review set out to identify and compile the current knowledge of all peer-reviewed studies on synovial fibroblasts from patients with juvenile idiopathic arthritis. The aim was to map the current knowledge and to produce a tool to assist future studies. The entire MEDLINE, EMBASE and Web of Science databases were used to identify all published studies in English regarding synovial fibroblasts from patients with juvenile idiopathic arthritis. We identified 18 eligible studies out of a total of 1778 screened entries. The majority of studies identified synovial fibroblast subsets or functional characteristics that may be involved in disease pathogenesis. We identified mechanisms of cell-cell interaction with leukocytes, pro-inflammatory signaling and unfavorable connective tissue homeostasis that may contribute to cartilage damage or bony overgrowth. All included studies identified mechanisms potentially linking synovial fibroblasts to specific disease traits in juvenile idiopathic arthritis. Most findings were similar to mechanisms also described in synovial fibroblast from adults with arthritis. However, the limited number of studies found identifies an unmet need for additional studies on synovial fibroblasts and their potential role in juvenile idiopathic arthritis.

Upregulation of IL-15 in the placenta alters trophoblasts behavior contributing to gestational diabetes mellitus

Background

Interleukin-15 (IL-15), a member of the ‘four α-helix bundle’ cytokine family, has been associated with many inflammatory and metabolic diseases. Abnormal expression of IL-15 has been linked to the occurrence and development of obesity and diabetes. However, there is a paucity of research on the involvement of IL-15 in Gestational Diabetes Mellitus (GDM). This study aims at investigating the role of IL-15 in the pathogenesis of GDM.

Results

IL-15 was consistently expressed in the placenta throughout pregnancy and dynamically changed with pregnancy progress. Trophoblasts have been identified as the major source of IL-15 in the placenta. Expression of IL-15 was significantly increased in the placenta of GDM and in the trophoblasts cultured with high glucose (HG). In our study, expression of IL-15 in the placenta was positively correlated with blood glucose concentration of 75 g Oral Glucose Tolerance Test (OGTT), and was inversely correlated with weight of newborns. Further investigations in vitro showed that exogenous addition of IL-15 promoted trophoblasts proliferation, improved invasion and tube formation ability by activating the JAK/STAT signaling pathway, which be blocked by JAK inhibitors.

Conclusion

Our results demonstrated that IL-15 expression in the placenta was dynamically changing during pregnancy, and it was upregulated in the placenta of GDM patients. Furthermore, IL-15 altered the biological behavior of trophoblasts through JAK/STAT signaling pathway in vitro, and may contributed to the placental pathology of GDM. Our findings provide a new direction for studying the pathophysiological changes of placenta in GDM.

The anti-inflammatory potential of cefazolin as common gamma chain cytokine inhibitor

A continuing quest for specific inhibitors of proinflammatory cytokines brings promise for effective therapies designed for inflammatory and autoimmune disorders. Cefazolin, a safe, first-generation cephalosporin antibiotic, has been recently shown to specifically interact with interleukin 15 (IL-15) receptor subunit α (IL-15Rα) and to inhibit IL-15-dependent TNF-α and IL-17 synthesis. The aim of this study was to elucidate cefazolin activity against IL-2, IL-4, IL-15 and IL-21, i.e. four cytokines sharing the common cytokine receptor γ chain (γ_c). In silico, molecular docking unveiled two potential cefazolin binding sites within the IL-2/IL-15Rβ subunit and two within the γ_c subunit. In vitro, cefazolin decreased proliferation of PBMC (peripheral blood mononuclear cells) following IL-2, IL-4 and IL-15 stimulation, reduced production of IFN-γ, IL-17 and TNF-α in IL-2- and IL-15-treated PBMC and in IL-15 stimulated natural killer (NK) cells, attenuated IL-4-dependent expression of CD11c in monocyte-derived dendritic cells and suppressed phosphorylation of JAK3 in response to IL-2 and IL-15 in PBMC, to IL-4 in TF-1 (erythroleukemic cell line) and to IL-21 in NK-92 (NK cell line). The results of the study suggest that cefazolin may exert inhibitory activity against all of the γ_c receptor-dependent cytokines, i.e. IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21.

IL-15: a novel prosurvival signaling pathway in cardiomyocytes

Cardiovascular disease is the leading cause of death in Western countries. A major limitation of current treatments is the inability to efficiently repair or replace dead myocardium. Recently, stem cell-based therapies have been explored as an avenue to circumvent current therapeutic limitations. Overall, these therapies seem to result in small improvements in the contractile function of the heart. The exact mechanism(s) of action that underlie these improvements remain unknown, and it is believed that paracrine effects play a significant role. Previously, we had reported that an extract derived from bone marrow cells, in the absence of any live cell, contained cardioprotective soluble factors. In this study, we identify IL-15 as a putative cardioprotectant within the bone marrow cells paracrine profile. Using an in vitro culture system, we assessed the ability of IL-15 to protect cardiomyocytes under hypoxic conditions. For the first time, we have identified IL-15 receptors on the surface of cardiomyocytes and delineated the signaling system by which hypoxic cardiomyocytes may be protected from cellular death and rescued from oxidative stress with IL-15 treatment.

Effects of interleukin-15 on neuronal differentiation of neural stem cells

Interleukin-15 (IL-15) signaling has pleiotropic actions in many cell types during development and has been best studied in cells of immune system lineage, where IL-15 stimulates proliferation of cytotoxic T cells and induces maturation of natural killer cells. A few reports have indicated that IL-15 and the IL-15 receptor are expressed in central nervous system tissues and neuronal cell lines. Because this aspect of IL-15 action is poorly studied, we used cultured rat neural stem cells (NSCs) to study IL-15 signal transduction and activity. Primary cultures of rat NSCs in culture will form neurospheres and will differentiate into neuron, astrocyte, and oligodendrocyte progenitors under permissive conditions. We found by immunofluorescence that the IL-15Ralpha subunit of the IL-15 receptor was expressed in NSCs and differentiating neurons, but not astrocyte or oligodendrocyte progenitors. We also showed that IL-15 treatment reduced MAP-2 protein levels in neurons and could reduce neurite outgrowth in differentiating neurons but did not affect NSC proliferation, and cell proportions and viability of the corresponding lineage cells. In the presence of a STAT3 inhibitor, Stattic, IL-15 no longer reduced MAP-2 protein levels. IL-15 treatment caused STAT3 phosphorylation. Furthermore, using anti-IL-15Ralpha antibody to block IL-15 signaling completely inhibited IL-15-induced phosphorylation of STAT3 and prevented IL-15 from decreasing neurite outgrowth. In conclusion, IL-15 may influence neural cell differentiation through a signal transduction pathway involving IL-15Ralpha and STAT3. This signal transduction modifies MAP-2 protein levels and, consequently, the differentiation of neurons from NSCs, as evidenced by reduced neurite outgrowth.

Abnormal mandibular growth and the condylar cartilage

Deviations in the growth of the mandibular condyle can affect both the functional occlusion and the aesthetic appearance of the face. The reasons for these growth deviations are numerous and often entail complex sequences of malfunction at the cellular level. The aim of this review is to summarize recent progress in the understanding of pathological alterations occurring during childhood and adolescence that affect the temporomandibular joint (TMJ) and, hence, result in disorders of mandibular growth. Pathological conditions taken into account are subdivided into (1) congenital malformations with associated growth disorders, (2) primary growth disorders, and (3) acquired diseases or trauma with associated growth disorders. Among the congenital malformations, hemifacial microsomia (HFM) appears to be the principal syndrome entailing severe growth disturbances, whereas growth abnormalities occurring in conjunction with other craniofacial dysplasias seem far less prominent than could be anticipated based on their often disfiguring nature. Hemimandibular hyperplasia and elongation undoubtedly constitute the most obscure conditions that are associated with prominent, often unilateral, abnormalities of condylar, and mandibular growth. Finally, disturbances of mandibular growth as a result of juvenile idiopathic arthritis (JIA) and condylar fractures seem to be direct consequences of inflammatory and/or mechanical damage to the condylar cartilage.

Therapeutic potential of interleukin-15: a myokine involved in muscle wasting and adiposity

Since the discovery of IL-15 and its role in T-cell proliferation in 1994, different studies on the effects of the cytokine on metabolic effects have been performed. These studies have mainly been involved with the metabolic pathways involved in lipid and protein metabolism. The present review summarises the metabolic effects of IL-15 at different target tissues and the possibilities and potential for therapeutic interventions based on the cytokine's roles in obesity and wasting.