Yin-Yang 1 transcription factor modulates ST2 expression during adverse cardiac remodeling post-myocardial infarction.

BACKGROUND: The cardioprotective effects of metformin remain poorly defined. Interleukin (IL)-33/ST2L signaling is a novel cardioprotective pathway, which is antagonized by the soluble isoform sST2. No data exist about the regulation of ST2 expression. This study aimed to evaluate the pathophysiological implication of Yin-Yang 1 (Yy1) transcription factor in cardiac remodeling and the expression of the soluble ST2 isoform. METHODS AND RESULTS: Myocardial infarction (MI) was induced in Wistar rats randomly receiving metformin or saline solution by permanent ligation of the left anterior coronary artery. In addition, a model of cardiomyocyte "biochemical strain" was used. Metformin administration improved post-MI cardiac remodeling, an effect that was associated with increased IL-33 and reduced sST2 levels in the myocardium. The anti-remodeling effects of metformin were also associated with a decrease in the transcription factor Yy1 intranuclear level and lower levels of phosphorylated HDAC4 within the cytoplasmic space. These effects were also observed in a cardiomyocyte biochemical strain model, where Yy1 silencing or HDAC4 inhibition blocked sST2 production in cardiomyocytes. Metformin blocked the HDAC4 phosphorylation induced by MI, preventing its export from the nucleus to the cytosol. The presence of dephosphorylated HDAC4 in the nucleus acted as a co-repressor of Yy1, repressing sST2 expression. CONCLUSION: The transcription factor Yy1 regulates sST2 expression, and repression of Yy1 by metformin results in lower levels of sST2 that are associated with favorable myocardial remodeling. The manipulation of YY1 or its co-repressor HDAC4 emerge as new targets to modulate ST2/IL33 signaling and prevent adverse cardiac remodeling.

Adenovirus-mediated overexpression of sST2 attenuates cardiac injury in the rat with severe acute pancreatitis.

AIMS: Severe acute pancreatitis (SAP) is a serious disease associated with systematic inflammation and multiple organs dysfunction. Soluble ST2 (sST2), a member of the Toll interleukin (IL)-1 receptor (TIR) superfamily, has been demonstrated to exert immune-regulatory and anti-inflammatory properties in several inflammation-related diseases. In this study, we investigated whether transfer of sST2 gene by adenovirus vector could attenuate sodium taurocholate-induced SAP and associated cardiac injury. MAIN METHODS: A rat model of SAP was induced by retrograde injection of 5% sodium taurocholate (1 ml/kg) into the biliopancreatic duct. Rats in the treatment groups were intravenously injected with adenovirus expressing sST2 (Ad-sST2, 1 × 109 particles/rat) or green fluorescent protein (Ad-GFP) via the tail vein 48 h before SAP induction. Histological changes in the pancreatic and heart tissues, and parameters for evaluating SAP and associated cardiac injury were determined at 24 h after SAP. KEY FINDINGS: Sodium taurocholate induced obvious pathological changes in pancreas and elevated serum levels of amylase and lipase. Furthermore, SAP animals exhibited significant cardiac impairment, evidenced by decreased cardiac function, increased myocardial apoptosis and cardiac-related enzymes including creatine kinase isoenzyme, lactate dehydrogenase, and Troponin T. Administration of Ad-sST2 markedly improved the structure of pancreas and heart tissues, and reversed the alterations in serum amylase, lipase and cardiac-related enzymes. In addition, Ad-sST2 treatment downregulated pro-inflammatory cytokines production, demonstrating the anti-inflammatory property of sST2. SIGNIFICANCE: Our results suggest that administration of Ad-sST2 significantly attenuated the severity of SAP and associated cardiac damage, and the cardioprotective effect is associated with its anti-inflammatory action.

IL-33/ST2 signaling contributes to radicular pain by modulating MAPK and NF-κB activation and inflammatory mediator expression in the spinal cord in rat models of noncompressive lumber disk herniation.

BACKGROUND: Immune and inflammatory responses occurring in the spinal cord play a pivotal role in the progression of radicular pain caused by intervertebral disk herniation. Interleukin-33 (IL-33) orchestrates inflammatory responses in a wide range of inflammatory and autoimmune disorders of the nervous system. Thus, the purpose of this study is to investigate the expression of IL-33 and its receptor ST2 in the dorsal spinal cord and to elucidate whether the inhibition of spinal IL-33 expression significantly attenuates pain-related behaviors in rat models of noncompressive lumbar disc herniation. METHODS: Lentiviral vectors encoding short hairpin RNAs that target IL-33 (LV-shIL-33) were constructed for gene silencing. Rat models of noncompressive lumber disk herniation were established, and the spines of rats were injected with LV-shIL-33 (5 or 10 µl) on the first day after the operation. Mechanical thresholds were evaluated during an observation period of 21 days. Moreover, the expression levels of spinal tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and cyclooxygenase 2 (COX-2) and the activation of the mitogen-activated protein kinases (MAPK) and nuclear factor-κB (NF-κB) pathways were evaluated to gain insight into the mechanisms related to the contribution of IL-33/ST2 signaling to radicular pain. RESULTS: The application of nucleus pulposus (NP) to the dorsal root ganglion (DRG) induced an increase in IL-33 and ST2 expression in the spinal cord, mainly in the dorsal horn neurons, astrocytes, and oligodendrocytes. Spinally delivered LV-shIL-33 knocked down the expression of IL-33 and markedly attenuated mechanical allodynia. In addition, spinal administration of LV-shIL-33 reduced the overexpression of spinal IL-1ß, TNF-α, and COX-2 and attenuated the activation of C-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and NF-κB/p65 but not p38. CONCLUSIONS: This study indicates that spinal IL-33/ST2 signaling plays an important role in the development and progression of radicular pain in rat models of noncompressive lumber disk herniation. Thus, the inhibition of spinal IL-33 expression may provide a potential treatment to manage radicular pain caused by intervertebral disk herniation.

Salient type 1 interleukin 1 receptor expression in peripheral non-immune cells.

Interleukin 1 is a pleiotropic cytokine that mediates diverse functions through its receptor, type I interleukin 1 receptor (IL-1R1). Most previous studies have focused on the expression and function of IL-1R1 in immune cells. Here we performed a comprehensive mapping of IL-1R1 distribution in multiple peripheral tissues using our IL-1R1 reporter (IL-1R1GR/GR) mice. This method yielded the highest sensitivity of in situ detection of IL-1R1 mRNA and protein. Besides validating previously reported IL-1R1 expression in the endocrine tissues including pituitary and pancreas, our results refuted previously reported exclusive IL-1R1 expression in neurons of the spinal cord dorsal horn and dorsal root ganglia (DRG). Instead, IL-1R1 expression was detected in endothelial cells within DRG, spinal cord, pancreas, colon, muscles and many immune organs. In addition, gp38+ fibroblastic reticular cells (FRCs), rather than tissue macrophages or other immune cells, were found to express high levels of IL-1R1 in colon and many immune organs. A functional test of spleen FRCs showed that they responded rapidly to systemic IL-1ß stimulation in vivo. Taken together, this study provides a rigorous re-examination of IL-1R1 expression in peripheral tissues and reveals tissue FRCs as a previously unappreciated novel high IL-1R1-expressing cell type in peripheral IL-1 signaling.

Bifidobacterium adolescentis protects against necrotizing enterocolitis and upregulates TOLLIP and SIGIRR in premature neonatal rats.

BACKGROUND: Necrotizing enterocolitis (NEC) is a serious gastrointestinal disorder that is often seen in premature infants. Probiotics decrease the risk of NEC; however, the mechanism by which probiotics work is not clear. The goal of this study was to evaluate the preventive effect of Bifidobacterium adolescentis in an NEC rat model. METHODS: Sprague-Dawley neonatal rats were obtained by caesarean section after 20-21 d gestation and randomly divided into the following 3 groups: dam fed (DF), formula fed (FF), and formula + B. adolescentis (FB). Those in the FF and FB groups developed NEC after exposure to asphyxia and cold stress. All rats were sacrificed 72 h after birth and intestinal injury and mRNA expression of TLR4, TOLLIP and SIGIRR were assessed. RESULTS: B. adolescentis significantly increased the 72-h survival rate from 56.3% in the FF group to 86.7% in the FB group. B. adolescentis significantly reduced the histological score from a median of 3.0 in the FF group to a median of 1.0 in the FB group,and significantly decreased the rate of NEC-like intestinal injury from 77.8% in the FF group to 23.1% in the FB group. The mRNA expression of TLR4 increased 3.6 fold in the FF group but decreased by 2 fold from B. adolescentis treatment. mRNA expression of TOLLIP and SIGIRR decreased 4.3 and 3.7 fold, respectively, in the FF group. B. adolescentis significantly increased mRNA expression of TOLLIP and SIGIRR by 3.7 fold and 2.6 fold, respectively. CONCLUSIONS: This study demonstrated B. adolescentis prevents NEC in preterm neonatal rats and that the mechanism for this action might be associated with the alteration of TLR4, TOLLIP, and SIGIRR expression.

Normal Oral Keratinocytes and Head and Neck Squamous Carcinoma Cells Induce an Innate Response of Fibroblasts.

BACKGROUND: Tumor stroma is similar to the connective tissue of chronic inflammation. The extracellular matrix of tumors is formed by cancer-associated fibroblasts that also modulate the inflammatory response. MATERIALS AND METHODS: We studied the ability of oral keratinocytes (NOK) and oral squamous cell carcinoma cells (SCC) to induce an innate immune response in fibroblasts. Co-cultures with fibroblasts in collagen gels and keratinocytes in inserts were used. Pentraxin 3 (PTX3) was used as an indicator of an innate immune response. RESULTS: SCC and NOK up-regulated fibroblast mRNA expression and protein release of PTX3. mRNA levels were more pronounced in cultures with malignant cells. The induction of PTX3 was abrogated by an interleukin-1 receptor antagonist CONCLUSION: Keratinocytes have the capacity to induce an interleukin-1-dependent innate immune response by fibroblasts in vitro. This could be important for subsequent fibroblast modulation of the inflammatory reaction in non-malignant and malignant disease processes.

Costimulation Endows Immunotherapeutic CD8 T Cells with IL-36 Responsiveness during Aerobic Glycolysis.

CD134- and CD137-primed CD8 T cells mount powerful effector responses upon recall, but even without recall these dual-costimulated T cells respond to signal 3 cytokines such as IL-12. We searched for alternative signal 3 receptor pathways and found the IL-1 family member IL-36R. Although IL-36 alone did not stimulate effector CD8 T cells, in combination with IL-12, or more surprisingly IL-2, it induced striking and rapid TCR-independent IFN-γ synthesis. To understand how signal 3 responses functioned in dual-costimulated T cells we showed that IL-2 induced IL-36R gene expression in a JAK/STAT-dependent manner. These data help delineate a sequential stimulation process where IL-2 conditioning must precede IL-36 for IFN-γ synthesis. Importantly, this responsive state was transient and functioned only in effector T cells capable of aerobic glycolysis. Specifically, as the effector T cells metabolized glucose and consumed O2, they also retained potential to respond through IL-36R. This suggests that T cells use innate receptor pathways such as the IL-36R/axis when programmed for aerobic glycolysis. To explore a function for IL-36R in vivo, we showed that dual costimulation therapy reduced B16 melanoma tumor growth while increasing IL-36R gene expression. In summary, cytokine therapy to eliminate tumors may target effector T cells, even outside of TCR specificity, as long as the effectors are in the correct metabolic state.

Potential roles of microRNA-29a in the molecular pathophysiology of T-cell acute lymphoblastic leukemia.

Recent evidence has shown that deregulated expression of members of the microRNA-29 (miR-29) family may play a critical role in human cancer, including hematological malignancies. However, the roles of miR-29 in the molecular pathophysiology of T-cell acute lymphoblastic leukemia (T-ALL) has not been investigated. Here, we show that lower levels of miR-29a were significantly associated with higher blast counts in the bone marrow and with increased disease-free survival in T-ALL patients. Furthermore, miR-29a levels are extremely reduced in T-ALL cells compared to normal T cells. Microarray analysis following introduction of synthetic miR-29a mimics into Jurkat cells revealed the downregulation of several predicted targets (CDK6, PXDN, MCL1, PIK3R1, and CXXC6), including targets with roles in active and passive DNA demethylation (such as DNMT3a, DNMT3b, and members of the TET family and TDG). Restoring miR-29a levels in Jurkat and Molt-4 T-ALL cells led to the demethylation of many genes commonly methylated in T-ALL. Overall, our results suggest that reduced miR-29a levels may contribute to the altered epigenetic status of T-ALL, highlighting its relevance in the physiopathology of this disease.

Expression and localization of interleukin 1 beta and interleukin 1 receptor (type I) in the bovine endometrium and embryo.

The interleukin-1 (IL1) system likely mediates mammalian embryo-maternal communication. In cattle, we have reported that the uterine fluid of heifers carrying early embryos shows downregulated IL1 beta (IL1B), which could lead to reduced NFkB expression and dampening of maternal innate immune responses. In this work, we assessed the expression of IL 1 beta (IL1B) and its receptor, interleukin 1 receptor type I (IL1R1) in the bovine endometrium and embryos by RT-PCR, immunohistochemistry and Western blot at the time of blastocyst development. Day 8 endometrium, both collected from animals after transfer of day 5 embryos (ET) and sham transferred (ST), showed IL1B and IL1R1 mRNA transcription and protein co-localization. Similarly, day 8 blastocyst, from ET animals and entirely produced in vitro, showed IL1R1 mRNA transcription and IL1B and IL1R1 protein co-localization. IL1B mRNA was detected in the analyzed blastocysts, but at very low levels that precluded its quantification. IL1B and IL1R1 immunostaining was observed in luminal epithelial cells, glandular epithelium and stromal cells. The presence of embryos increased endometrial IL1B protein locally, while no differences regarding IL1R1 protein and IL1B and IL1R1 mRNA were detected. These results suggest that the early preimplantation bovine embryo in the maternal tract might interact with the maternal immune system through the IL1 system. Such a mechanism may allow the embryo to elicit local endometrial responses at early stages, which are required for the development of a receptive endometrium.

Membrane translocation of IL-33 receptor in ventilator induced lung injury.

Ventilator-induced lung injury is associated with inflammatory mechanism and causes high mortality. The objective of this study was to discover the role of IL-33 and its ST2 receptor in acute lung injury induced by mechanical ventilator (ventilator-induced lung injury; VILI). Male Wistar rats were intubated after tracheostomy and received ventilation at 10 cm H2O of inspiratory pressure (PC10) by a G5 ventilator for 4 hours. The hemodynamic and respiratory parameters were collected and analyzed. The morphological changes of lung injury were also assessed by histological H&E stain. The dynamic changes of lung injury markers such as TNF-α and IL-1ß were measured in serum, bronchoalveolar lavage fluid (BALF), and lung tissue homogenization by ELISA assay. During VILI, the IL-33 profile change was detected in BALF, peripheral serum, and lung tissue by ELISA analysis. The Il-33 and ST2 expression were analyzed by immunohistochemistry staining and western blot analysis. The consequence of VILI by H&E stain showed inducing lung congestion and increasing the expression of pro-inflammatory cytokines such as TNF-α and IL-1ß in the lung tissue homogenization, serum, and BALF, respectively. In addition, rats with VILI also exhibited high expression of IL-33 in lung tissues. Interestingly, the data showed that ST2L (membrane form) was highly accumulated in the membrane fraction of lung tissue in the PC10 group, but the ST2L in cytosol was dramatically decreased in the PC10 group. Conversely, the sST2 (soluble form) was slightly decreased both in the membrane and cytosol fractions in the PC10 group compared to the control group. In conclusion, these results demonstrated that ST2L translocation from the cytosol to the cell membranes of lung tissue and the down-expression of sST2 in both fractions can function as new biomarkers of VILI. Moreover, IL-33/ST2 signaling activated by mechanically responsive lung injury may potentially serve as a new therapy target.

Corilagin Protects Against HSV1 Encephalitis Through Inhibiting the TLR2 Signaling Pathways In Vivo and In Vitro.

In this study, we tried to explore the molecular mechanism that Corilagin protected against herpes simplex virus-1 encephalitis through inhibiting the TLR2 signaling pathways in vivo and in vitro. As a result, Corilagin significantly prevented increase in the levels of TLR2 and its downstream mediators following Malp2 or HSV-1 challenge. On the other hand, in spite of TLR2 knockdown, Corilagin could still significantly suppress the expression of P38 and NEMO, phosphor-P38, and nuclear factor kappa B. The mRNA and protein expression of TLR2 and its downstream mediators in the brain tissue were also significantly lowered in mice treated with Corilagin. In addition, Corilagin inhibited expression of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 protein. In conclusion, Corilagin shows the potential to protect against HSV-1-induced encephalitis, and the beneficial effects may be mediated by inhibiting TLR2 signaling pathways.

Relevance of the myeloid differentiation factor 88 (MyD88) on RANKL, OPG, and nod expressions induced by TLR and IL-1R signaling in bone marrow stromal cells.

The myeloid differentiation factor 88 (MyD88) plays a pivotal role in Toll-like receptor (TLR)- and interleukin-1 receptor (IL-1R)-induced osteoclastogenesis. We examined the role of MyD88 on p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) activation and nucleotide-binding oligomerization domain (Nod) induction by lipopolysaccharide (LPS) and IL-1 beta, and their effect on receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) production in bone marrow stromal cell (BMSC). RANKL, Nod1, Nod2, NF-κB, and p38 protein levels were determined by Western blot. Nod2 was stimulated with muramyl dipeptide (MDP) prior to TLR4 stimulation with LPS. MyD88 deficiency markedly inhibited RANKL expression after LPS stimulation and increased OPG messenger RNA (mRNA) production. Also, MyD88 was necessary for NF-κB and p38 MAPK activation. MDP alone did not induce RANKL and OPG expressions; however, when combined with LPS, their expressions were significantly increased (p < 0.05). Our results support that MyD88 signaling has a pivotal role in osteoclastogenesis thought NF-κB and p38 activation. Nod2 and especially Nod1 levels were influenced by MyD88.

Global identification of genes targeted by DNMT3b for epigenetic silencing in lung cancer.

The maintenance cytosine DNA methyltransferase DNMT1 and de novo methyltransferase DNMT3b cooperate to establish aberrant DNA methylation and chromatin complexes to repress gene transcription during cancer development. The expression of DNMT3b was constitutively increased 5-20-fold in hTERT/CDK4-immortalized human bronchial epithelial cells (HBECs) before treatment with low doses of tobacco carcinogens. Overexpression of DNMT3b increased and accelerated carcinogen-induced transformation. Genome-wide profiling of transformed HBECs identified 143 DNMT3b-target genes, many of which were transcriptionally regulated by the polycomb repressive complex 2 (PRC2) complex and silenced through aberrant methylation in non-small-cell lung cancer cell lines. Two genes studied in detail, MAL and OLIG2, were silenced during transformation, initially through enrichment for H3K27me3 and H3K9me2, commonly methylated in lung cancer, and exert tumor suppressor effects in vivo through modulating cancer-related pathways. Re-expression of MAL and OLIG2 to physiological levels dramatically reduced the growth of lung tumor xenografts. Our results identify a key role for DNMT3b in the earliest stages of initiation and provide a comprehensive catalog of genes targeted for silencing by this methyltransferase in non-small-cell lung cancer.

Mineralocorticoid receptor antagonists modulate galectin-3 and interleukin-33/ST2 signaling in left ventricular systolic dysfunction after acute myocardial infarction.

OBJECTIVES: This study aimed to evaluate the specific role of the 2 available mineralocorticoid receptor antagonists (MRAs), eplerenone and spironolactone, on the modulation of galectin-3 (Gal-3) and interleukin (IL)-33/ST2 signaling in an experimental model of left ventricular systolic dysfunction after acute myocardial infarction (MI). BACKGROUND: The molecular mechanisms of benefits of MRAs in patients with left ventricular systolic dysfunction after MI not well understood. METHODS: MI and left ventricular systolic dysfunction were induced by permanent ligation of the anterior coronary artery in 45 male Wistar rats, randomly assigned to no therapy (MI group, n = 15) or to receive MRAs (100 mg/kg/day) for 4 weeks; either eplerenone (n = 15) or spironolactone (n = 15) was used. A sham group was used as a control (n = 8). Elements of the pathway for Gal-3 including transforming growth factor (TGF)-ß and SMAD3, as well as that for IL-33/ST2 (including IL-33 and soluble ST2 [sST2]) were analyzed in the infarcted and noninfarcted myocardium by quantitative real-time reverse transcription polymerase chain reaction. Expression of markers of fibrosis (collagen types I and III, tissue inhibitor of metalloproteinase-1) and inflammation (IL-6, tumor necrosis factor-α, monocyte chemotactic protein-1) was also examined. RESULTS: In the infarcted myocardium, compared with sham animals, the MI group had higher concentrations of Gal-3, TGF-ß, SMAD3, IL-33, and sST2, as well as higher concentrations of markers of fibrosis and inflammation. Treatment with MRAs down-regulated Gal-3, TGF-ß, and SMAD3 and enhanced IL-33/ST2 signaling with lower expression of sST2; protective IL-33 up-regulation was unaffected by MRAs. Modulation of Gal-3 and IL-33/ST2 signaling induced by MRAs correlated with lower expression levels of fibrosis and inflammatory markers. No differences were found between eplerenone and spironolactone. In the noninfarcted myocardium, compared with sham animals, the MI group exhibited a higher expression of Gal-3 and IL-33, but no signs of inflammation or fibrosis were observed; in the presence of MRAs, IL-33 expression was significantly up-regulated, but Gal-3 was unaffected. CONCLUSIONS: MRAs play a pivotal role in the Gal-3 and IL-33/ST2 modulation in post-MI cardiac remodeling.

Expression of TIR8 receptor in chicken tissues.

The orphan receptor TIR8, also known as SIGIRR, belongs to the TLR/IL-1R (TIR) superfamily and plays an important role in the immune response. The signalling pathways of the receptors belonging to the TIR family are tightly regulated at multiple levels and through different mechanisms. TIR8 negatively modulates innate immunity and inflammatory responses in the areas where it is primarily expressed (gastrointestinal tract, kidney and lung). TIR8 has been well characterized in mouse, humans and in other Mammalian species, but it is still poorly known in chicken. Given the importance of gastrointestinal diseases in chicken, the aim of our study was to investigate the distribution of TIR8 in a wide panel of non-pathologic tissues and organs. TIR8 expression was analyzed in chicken samples at both levels of transcript mRNA and translated protein. The pattern of expression of TIR8 (ubiquitous) was similar to Mammals for some tissues (high levels in kidney and gastrointestinal tract), but it resulted unique for other tissues. High expression was detected in liver, pancreas and female reproductive tract. Interestingly, the receptor was highly expressed also in heterophils, the most common granulocytes of birds. Few isoforms of chicken TIR8 were detected by Western blot, suggesting the occurrence of different post-translational processing in different organs. Immunohistochemistry revealed TIR8 immunolabelling in chicken intestine and thymus. These results demonstrate that the receptor, although evolutionarily conserved, show species-specific peculiarities.

Increased Th17 differentiation in aged mice is significantly associated with high IL-1ß level and low IL-2 expression.

OBJECTIVE: Aging has been reported to be associated with changes in immune function. Although frequent infection and the development of malignancy suggest the decline of immune function with aging, changes toward proinflammatory conditions also develop at the same time. Th17 cells are well known CD4(+) T cell subpopulation closely linked to chronic inflammation and autoimmunity. In this study, changes in the Th17 population were investigated to elucidate a possible mechanism for this response with aging. METHODS: Splenocytes were isolated from 2-month-old (young) and 20-month-old (aged) mice. CD4(+)CD44(+) memory T cells and CD4(+)CD62L(+) naïve T cells were isolated and sorted using magnetic beads and flow cytometry. The frequency of IL-17-producing cells was measured using flow cytometry. The expression of IL-17 and Th17-related factors at the mRNA level was measured with RT-PCR. IL-17 and Il-1ß expression in spleen tissues was additionally assessed using confocal microscopy. RESULTS: The proportion of IL-17-producing CD4(+) T cells was higher in the splenocytes among the old mice than those of the young mice. When splenocytes were cultured in Th17 polarizing conditions, the proportion of IL-17 producing CD4(+) T cells was higher in aged mice as well. This was consistently observed when naïve and memory cells were isolated and differentiated into Th17 respectively. In addition, the expression of retinoic acid receptor-related orphan nuclear receptor gamma t (RORγt) and other Th17-related factors (AhR, CCR6, and CCL20) increased in the splenocytes of aged mice compared to the young mice. The expression of IL-1ß, showing to promote Th17 differentiation, was higher in the aged mice. Likewise, CD4(+) T cell expression of IL-1R was higher in the aged mice, suggesting that the CD4(+) T cells of the aged mice are readily prepared to differentiate into Th17 cells in response to IL-1ß. Confocal microscopy showed that cells positive for IL-1R or IL-1ß were more frequent in the spleens of the aged mice. When an anti-IL-2 antibody was applied, the proportion of IL-17-producing cells increased more prominently in the young mice. We observed that IL-2 production and IL-2R expression were reduced in the aged mice, respectively, explaining the blunted response to the anti-IL-2 antibody treatment and the consequent minimal change in the Th17 population. CONCLUSION: We demonstrated that the proportion of Th17 cells increased in the aged mice both in naïve and memory cell populations. Elevation of IL-1R and IL-1ß expression and the reduction in IL-2 and IL-2R expression in aged mice seemed to promote Th17 differentiation. Our results suggest that enhanced Th17 differentiation in aging may have a pathogenic role in the development of Th17-mediated autoimmune diseases.

Sustained IL-1ß expression impairs adult hippocampal neurogenesis independent of IL-1 signaling in nestin+ neural precursor cells.

Alterations in adult hippocampal neurogenesis have been observed in numerous neurological diseases that contain a neuroinflammatory component. Interleukin-1ß (IL-1ß) is a pro-inflammatory cytokine that contributes to neuroinflammation in many CNS disorders. Our previous results reveal a severe reduction in adult hippocampal neurogenesis due to focal and chronic expression of IL-1ß in a transgenic mouse model, IL-1ß(XAT), that evokes a complex neuroinflammatory response. Other investigators have shown that IL-1ß can bind directly to neural precursors to cause cell cycle arrest in vitro. In order to observe if IL-1 signaling is necessary in vivo, we conditionally knocked out MyD88, an adapter protein essential for IL-1 signaling, in nestin(+) neural precursor cells (NPCs) in the presence of IL-1ß-dependent inflammation. Our results show that conditional knockout of MyD88 does not prevent IL-1ß-induced reduction in neuroblasts using a genetic fate mapping model. Interestingly, MyD88 deficiency in nestin(+) NPCs causes an increase in the number of astrocytes in the presence of IL-1ß, suggesting that MyD88-dependent signaling is important in limiting astroglial differentiation due to inflammation. MyD88 deficiency does not alter the fate of NPCs in the absence of inflammation. Furthermore, the inflammatory milieu due to IL-1ß is not affected by the absence of MyD88 in nestin(+) NPCs. These results show that sustained IL-1ß causes a reduction in adult hippocampal neurogenesis that is independent of MyD88-dependent signaling in nestin(+) NPCs, suggesting an indirect negative effect of IL-1ß on neurogenesis.

Inhibition of acetylcholinesterase activity by rivastigmine decreases lipopolysaccharide-induced IL-1ß expression in the hypothalamus of ewes.

The present study was designed to determine the effect of subcutaneous rivastigmine treatment on IL-1ß expression and IL-1 type I receptor (IL-1R1) gene expression in the hypothalamic structures (preoptic area [POA], anterior hypothalamus [AHA], and medial basal hypothalamus [MBH]) of ewes after lipopolysaccharide (LPS) treatment. Endotoxin treatment increased (P ≤ 0.01) both IL-1ß and IL-1R1 gene expression in the POA, AHA, and MBH compared with the control group, whereas concomitant rivastigmine and LPS injection abolished this stimulatory effect. It was also found that LPS elevated (P ≤ 0.01) IL-1ß concentration in the hypothalamus (71.0 ± 2.3 pg/mg) compared with controls (16.1 ± 3.6 pg/mg). The simultaneous injection of LPS and rivastigmine did not increase IL-1ß concentration in the hypothalamus (24.6 ± 13.0 pg/mg). This central change in IL-1ß synthesis seems to be an effect of acetylcholinesterase (AChE) inhibition by rivastigmine, which decreases (P ≤ 0.01) the activity of this enzyme from 78.5 ± 15.0 µmol · min(-1) · g(-1) of total protein in the control and 68.8 ± 9.8 µmol · min(-1) · g(-1) of total protein in LPS-treated animals to 45.2 ± 5.6 µmol · min(-1) · g(-1) of total protein in the rivastigmine and LPS-treated group. Our study showed that rivastigmine could effectively reverse the stimulatory effect of immune stress induced by LPS injection on IL-1ß synthesis through a decrease in AChE activity in the hypothalamic area of sheep. Our results also proved that the cholinergic anti-inflammatory pathway could directly modulate the central response to endotoxin.