Regulation Of IL-1α Research Articles

Expression and regulation of alarmin cytokine IL-1α in human retinal pigment epithelial cells

Human retinal pigment epithelial (hRPE) cells play important immune-regulatory roles in a variety of retinal pathologic processes, including the production of inflammatory cytokines that are essential mediators of the innate immune response within the ocular microenvironment. The pro-inflammatory “alarmin” cytokine IL-1α has been implicated in both infectious and non-infectious retinal diseases, but its regulation in the retina is poorly understood. The purpose of this study was to elucidate the expression and regulation of IL-1α within hRPE cells. To do this, IL-1α mRNA and protein in hRPE cells was assessed by RT-PCR, qPCR, ELISA, Western blot, and immunofluorescence following treatment with a variety of stimuli and inhibitors. ER stress, LPS, IL-1β, and TLR2 activation all significantly increased intracellular IL-1α protein. Increasing intracellular calcium synergized both LPS- and Pam3CSK4-induced IL-1α protein production. Accordingly, blocking calcium signaling and calpain activity strongly suppressed IL-1α protein expression. Significant but more moderate inhibition occurred following blockage of TLR4, caspase-4, or caspase-1. Neutralizing antibodies to IL-1β and TLR2 partially eliminated LPS- and TLR2 ligand Pam3CSK4-stimulated IL-1α protein production. IFN-β induced caspase-4 expression and activation, and also potentiated LPS-induced IL-1α expression, but IFN-β alone had no effect on IL-1α protein production. Interestingly, all inhibitors targeting the PI3K/Akt pathway, with the exception of Ly294002, strongly increased IL-1α protein expression. This study improves understanding of the complex mechanisms regulating IL-1α protein expression in hRPE cells by demonstrating that TLR4 and TLR2 stimulation and exposure to IL-1β, ER stress and intracellular calcium all induce hRPE cells to produce intracellular IL-1α, which is negatively regulated by the PI3K/Akt pathway. Additionally, the non-canonical inflammasome pathway was shown to be involved in LPS-induced hRPE IL-1α expression through caspase-4 signaling.

IL-1α Up-Regulates IL-6 Expression in Bovine Granulosa Cells via MAPKs and NF-κB Signaling Pathways

Background/Aims: IL-6 is one of the main cytokines in regulating ovarian follicular development and ovulation. However, the factors that regulate IL-6 expression in follicles are still unclear. The aim of this study was to elucidate the mechanisms underlying the effect of IL-1α on IL-6 expression in granulosa cells. Methods: IL-6 expression after IL-1α with/without inhibitors treatment was analyzed by RT-qPCR and ELISA. The phosphorylation of proteins induced by IL-1α was analyzed by western blot. The intracellular cAMP level was assayed by immunoassay kit. Results: IL-1α has a dose-dependent effect on IL-6 expression in granulosa cells. This promoting effect can be significantly attenuated by Erk, c-Jun, p38 and IκB proteins inhibitors, respectively. Moreover, the phosphorylation levels of Erk, c-Jun, p38 and IκBα proteins were significantly increased after IL-1α treatment. In addition, we also found that IL-1α not only reversed the cAMP attenuated IL-6 expression， but also increased IL-1α mRNA expression in granulosa cells. Conclusion: The regulation of IL-1α on IL-6 expression is mediated by activation of MAPKs and NF-κB signaling pathways. Moreover，IL-1α may regulate the ovulation-related genes expression in granulosa cells by an autocrine and/or paracrine manner.

161 - Redox-Dependent Calcium-Mediated Signaling Networks That Control the Senescence-Associated Secretory Phenotype

Cellular senescence has evolved as one of the protective mechanisms to arrest the growth of cells with oncogenic potential. While senescent cells lose the ability to divide, they remain metabolically active and adapt a senescence-associated secretory phenotype (SASP). The SASP is central to the progression of several age-associated disease pathologies perpetuated by inflammation. A key modulator of SASP is the pro-inflammatory cytokine interleukin-1 alpha (IL-1α) whose expression and activity is responsive to the senescence-associated (SA) oxidant production and the accompanying disruption of calcium (Ca2+) homeostasis. Members of the Transient Receptor Potential (TRP) channel family control cellular Ca2+ and are sensitive to activation by steady state hydrogen peroxide (ss-H2O2). This study aims at determining the molecular identity of the Ca2+ channel(s) that control the activity of the SASP regulator IL-1α. Using primary IMR-90 human fetal lung fibroblasts as a cellular senescence model, we have begun to explore the likely channel responsible for increased Ca2+ entry in senescent cells. We establish the idea that the redox-responsive TRPM2/TRPC5 channel activity is compromised during senescence due to desensitization by increased ss-H2O2 and TRPC6 channel activity is elevated to compensate for this loss of H2O2-responsive channel activity, thereby modulating SA dysregulation of Ca2+. We hypothesize that modification of this Ca2+ channel in the senescent cells can limit the downstream processing and regulation of IL-1α thereby reversing the SASP. This can establish a new paradigm of communication between the mitochondrial reactive oxygen species (ROS), cytosolic Ca2+ and nuclear IL-1α in senescence. Also, IL-1 α and TRPC6 have been shown to be independently regulated by mechanistic target of rapamycin (mTOR) signaling, a nutrient sensing pathway involved in regulation of aging processes. Overall, these studies identifying the TRPC6-mediated IL1α regulatory loop in senescence have the potential to identify new therapeutic approaches that limit the disease promoting properties of senescent cells without impairing their ability to defend against oncogenic insult.

Effect of Hangeshashinto on calprotectin expression in human oral epithelial cells.

Oral epithelial cells produce antimicrobial peptides (AMPs) to prevent microbial infection. Calprotectin (S100A8/S100A9) is one of these AMPs in oral epithelial cells, the expression of which is up-regulated by interleukin-1α (IL-1α). Hangeshashinto (HST) is a traditional Japanese herbal medicine that has anti-inflammatory effects. The purpose of this study was to investigate the effect of HST on the expression of calprotectin through the regulation of IL-1α in oral epithelial cells. Human oral epithelial cells (TR146) were cultured with HST in the presence or absence of anti-IL-1α antibody or IL-1 receptor antagonist, or with six major components of HST (3,4-dihydroxybenzaldehyde, baicalin, ginsenoside Rb1, glycyrrhizin, oleanolic acid and berberine). The expression of S100A8, S100A9, other AMPs and cytokine mRNAs was examined by RT-PCR and quantitative real-time PCR. Calprotectin expression and IL-1α secretion were investigated by ELISA. HST (6 μg/ml) increased the expression of S100A8/S100A9 mRNAs and calprotectin protein, and also up-regulated β-defensin 2 (DEFB4) and S100A7 expression. The expression of IL-1α mRNA and its protein was slightly but significantly increased by HST. A neutralizing antibody against IL-1α and IL-1 receptor antagonist inhibited HST-up-regulated S100A8/S100A9 mRNA expression. Although 3,4-dihydroxybenzaldehyde, baicalin and ginsenoside Rb1 as HST components increased S100A8/S100A9 expression, oleanolic acid and berberine decreased their expression. These results suggest that HST increases the expression of calprotectin, DEFB4 and S100A7 in oral epithelial cells. In response to HST, up-regulation of calprotectin expression may be partially induced via IL-1α.

Seminal plasma induces the expression of IL-1α in normal and neoplastic cervical cells via EP2/EGFR/PI3K/AKT pathway.

BackgroundCervical cancer is a chronic inflammatory disease of multifactorial etiology usually presenting in sexually active women. Exposure of neoplastic cervical epithelial cells to seminal plasma (SP) has been shown to promote the growth of cancer cells in vitro and tumors in vivo by inducing the expression of inflammatory mediators including pro-inflammatory cytokines. IL-1α is a pleotropic pro-inflammatory cytokine induced in several human cancers and has been associated with virulent tumor phenotype and poorer prognosis. Here we investigated the expression of IL-1α in cervical cancer, the role of SP in the regulation of IL-1α in neoplastic cervical epithelial cells and the molecular mechanism underlying this regulation.Methods and resultsReal-time quantitative RT-PCR confirmed the elevated expression of IL-1α mRNA in cervical squamous cell carcinoma and adenocarcinoma tissue explants, compared with normal cervix. Using immunohistochemistry, IL-1α was localized to the neoplastically transformed squamous, columnar and glandular epithelium in all cases of squamous cell carcinoma and adenocarcinomas explants studied. We found that SP induced the expression of IL-α in both normal and neoplastic cervical tissue explants. Employing HeLa (adenocarcinoma) cell line as a model system we identified PGE2 and EGF as possible ligands responsible for SP-mediated induction of IL-1α in these neoplastic cells. In addition, we showed that SP activates EP2/EGFR/PI3kinase-Akt signaling to induce IL-1α mRNA and protein expression. Furthermore, we demonstrate that in normal cervical tissue explants the induction of IL-1α by SP is via the activation of EP2/EGFR/PI3 kinase-Akt signaling.ConclusionSP-mediated induction of IL-1α in normal and neoplastic cervical epithelial cells suggests that SP may promote cervical inflammation as well as progression of cervical cancer in sexually active women.

IL-1α BUT NOT IL-1β-INDUCED PROSTAGLANDIN SYNTHESIS IS INHIBITED BY CORTICOTROPIN-RELEASING FACTOR

Interleukin (IL)-1α and IL-1β share low amino acid homology, but exhibit a very similar array of biological activities. The authors previously showed negative regulation of IL-1α-induced prostaglandin (PG) production by corticotropin releasing factor (CRF). In this study, the authors compared the effect of CRF on IL-1α- and IL-1β-induced PG synthesis. IL-1α (100U/ml) increased prostacyclin (PGI2) (measured as 6-keto PGF1α[6K]) synthesis in endothelial cells and the production of PGE2in fibroblasts. The PG response to IL-1α was suppressed by simultaneous exposure to CRF (2.5×10−11–2.5×10−8M) in both cell types. IL-1α enhanced both phospholipase A2(PLA2) and prostaglandin H synthase (PGHS) activities, and the two effects were completely abrogated by CRF. IL- 1β (100U/ml) was as active as IL-1α in triggering release of PGI2from endothelial cells and PGE2from fibroblasts. However, CRF (2.5×10−11–2.5×10−8M) failed to alter the IL-1β-induced PG synthesis in both cell types. Following IL-1β PGHS activity, and to a lesser extent PLA2activity, were enhanced, however CRF only inhibited PGHS and not PLA2activity. It is concluded that although IL-1α and IL-1β usually produce similar biological effects, here they seem to act via different mechanisms. The different regulation of IL-1α and IL-1β pro-inflammatory activities by CRF may attribute special precision and specificity to the neuroendocrine-immune control of inflammatory processes.

Differential regulation of IL-1α, IL-1ra, and IL-1R2 by IL-1β stimulation in a skin organ culture model

Differential regulation of IL-1α, IL-1ra, and IL-1R2 by IL-1β stimulation in a skin organ culture model