A Role for PPARgamma in the Regulation of Cytokines in Immune Cells and Cancer

Uncovering the mechanism of troglitazone-mediated idiosyncratic drug-induced liver injury with individual-centric models

Idiosyncratic drug-induced liver injury is a rare and unpredictable event. Deciphering its initiating-mechanism is a hard task as its occurrence is individual dependent. Thus, studies that utilize models that are not individual-centric might drive to a general mechanistic conclusion that is not necessarily true. Here, we use the individual-centric spheroid model to analyze the initiating-mechanism of troglitazone-mediated iDILI risk. Individual-centric spheroid models were generated using a proprietary cell educating technology. These educated spheroids contain hepatocytes, hepatic stellate cells, activated monocyte-derived macrophages, and dendritic cells under physiological conditions. We show that phases 1 and 2 drug-metabolizing enzymes were induced in an individual-dependent manner. However, we did not observe any association of DEMs induction and troglitazone (TGZ)-mediated iDILI risk. We analyzed TGZ-mediated iDILI and found that a 44-year-old male showed iDILI risk that is associated with TGZ-mediated suppression of IL-12 expression by autologous macrophages and dendritic cells. We performed a rescue experiment and showed that treatment of spheroids from this 44-year-old male with TGZ and recombinant IL-12 suppressed iDILI risk. We confirmed the mechanism in another 31-year-old female with iDILI risk. We demonstrate here that individual-centric spheroid are versatile models that allow to predict iDILI risk and to analyze a direct effect of the drug on activated macrophages and dendritic cells to uncover the initiating-mechanism of iDILI occurrence. This model opens perspectives for a personalized strategy to mitigate iDILI risk.

TDAG51 deficiency attenuates dextran sulfate sodium-induced colitis in mice

Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is a group of chronic inflammatory diseases of the gastrointestinal tract. Although the multifactorial etiology of IBD pathogenesis is relatively well documented, the regulatory factors that confer a risk of IBD pathogenesis remain less explored. In this study, we report that T-cell death-associated gene 51 (TDAG51/PHLDA1) is a novel regulator of the development of dextran sulfate sodium (DSS)-induced colitis in mice. TDAG51 expression was elevated in the colon tissues of DSS-induced experimental colitis mice. TDAG51 deficiency protected mice against acute DSS-induced lethality and body weight changes and disease severity. DSS-induced structural damage and mucus secretion in colon tissues were significantly reduced in TDAG51-deficient mice compared with wild-type mice. We observed similar results in a DSS-induced chronic colitis mouse model. Finally, we showed that the production of inflammatory mediators, including proinflammatory enzymes, molecules and cytokines, was decreased in DSS-treated TDAG51-deficient mice compared with DSS-treated wild-type mice. Thus, we demonstrated that TDAG51 deficiency plays a protective role against DSS-induced colitis by decreasing the production of inflammatory mediators in mice. These findings suggest that TDAG51 is a novel regulator of the development of DSS-induced colitis and is a potential therapeutic target for IBD.

Regulation of Free Fatty Acid Receptor 4 on Inflammatory Gene Induced by LPS in Large Yellow Croaker (Larimichthys crocea)

Free fatty acid receptor 4 (FFAR4) plays a key role in regulating the inflammatory response in mammals. The present study aimed to investigate the function of large yellow croaker FFAR4 on inflammation. In the present study, ffar4 was widely expressed in 10 tissues of large yellow croaker including gill, head kidney and spleen. Further studies showed that treatment of head kidney macrophages with agonists (TUG891 or GSK137647A) or overexpression of ffar4 reduced the mRNA expression of pro-inflammatory genes induced by LPS, and increased the expression of pparγ. Treatment of macrophages with antagonist AH7614 increased the mRNA expression of pro-inflammatory genes induced by LPS, and decreased the mRNA expression of pparγ. In order to verify the immunomodulatory effect of PPARγ, PPARγ was overexpressed in macrophages which significantly reduced the mRNA expression of pro-inflammatory genes il6, il1β, il8, tnfα and cox2. Moreover, results of dual-luciferase assays showed that PPARγ downregulated the transcriptional activity of il6 and il1β promoters. In conclusion, FFAR4 showed anti-inflammatory effects on LPS-induced inflammation in large yellow croaker.

Genetic and pharmacological inhibition of fatty acid-binding protein 4 alleviated inflammation and early fibrosis after toxin induced kidney injury

Considerable data have suggested that acute kidney injury (AKI) is often incompletely repaired and could lead to chronic kidney disease (CKD). As we known, toxin-induced nephropathy triggers the rapid production of proinflammatory mediators and the prolonged inflammation allows the injured kidneys to develop interstitial fibrosis. In our previous study, fatty acid-binding protein 4 (Fabp4) has been reported to be involved in the process of AKI. However, whether Fabp4 plays crucial roles in toxin-induced kidney injury remained unclear. To explore the effect and mechanism of Fabp4 on toxin induced kidney injury, folic acid (FA) and aristolochic acid (AA) animal models were used. Both FA and AA injected mice developed severe renal dysfunction and dramatically inflammatory response (IL-6, MCP1 and TNF-a), which further lead to early fibrosis confirmed by the accumulation of extracellular matrix proteins (α-Sma, Fn, Col1 and Col4). Importantly, we found that FA and AA induced-kidney injury triggered the high expression of Fabp4 mRNA/protein in tubular epithelial cells. Furthermore, pharmacological and genetic inhibition of Fabp4 significantly attenuated FA and AA induced renal dysfunction, pathological damage, and early fibrosis via the regulation of inflammation, which is mediated by suppressing p-p65/p-stat3 expression via enhancing Pparγ activity. In summary, Fabp4 in tubular epithelial cells exerted the deleterious effects during the recovery of FA and AA induced kidney injury and the inhibition of Fabp4 might be an effective therapeutic strategy against the progressive AKI.

The role of glycogen synthase kinase 3 beta in multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) that leads to progressive neurological disability due to axonal deterioration. Although MS presents profound heterogeneity in the clinical course, its underlying central mechanism is active demyelination and neurodegeneration associated with inflammation. Multiple autoimmune and neuroinflammatory pathways are involved in the demyelination process of MS. Analysis of MS lesions has shown that inflammatory genes are upregulated. Glycogen synthase kinase-3 (GSK-3) is part of the mitogen-activated protein kinase (MAPK) family and has important roles in many signaling cascades. GSK-3 is a highly conserved serine/threonine protein kinase expressed in both the central and the peripheral nervous systems. GSK-3 modulates several biological processes through phosphorylation of protein kinases, including cell signaling, neuronal growth, apoptosis and production of pro-inflammatory cytokines and interleukins, allowing adaptive changes in events such as cellular proliferation, migration, inflammation, and immunity. GSK-3 occurs in mammals in two isoforms GSK-3α and GSK-3β, both of which are common in the brain, although GSK-3α is found particularly in the cerebral cortex, cerebellum, striated hippocampus and Purkinje cells, while GSK-3β is found in all brain regions. In patients with chronic progressive MS, expression of GSK-3β is elevated in several brain regions such as the corpus callosum and cerebral cortex. GSK-3β inhibition may play a role in glial cell activation, reducing pathological pain induced by nerve injury by formalin injection. According to the role of GSK-3β in pathological conditions, the aim of this article is review of the role of GSK-3β in multiple sclerosis and inflammation of neurons.

Induced Ketosis as a Treatment for Neuroprogressive Disorders: Food for Thought?

Induced ketosis (or ketone body ingestion) can ameliorate several changes associated with neuroprogressive disorders, including schizophrenia, bipolar disorder, and major depressive disorder. Thus, the effects of glucose hypometabolism can be bypassed through the entry of beta-hydroxybutyrate, providing an alternative source of energy to glucose. The weight of evidence suggests that induced ketosis reduces levels of oxidative stress, mitochondrial dysfunction, and inflammation-core features of the above disorders. There are also data to suggest that induced ketosis may be able to target other molecules and signaling pathways whose levels and/or activity are also known to be abnormal in at least some patients suffering from these illnesses such as peroxisome proliferator-activated receptors, increased activity of the Kelch-like ECH-associated protein/nuclear factor erythroid 2-related factor 2, Sirtuin-1 nuclear factor-κB p65, and nicotinamide adenine dinucleotide (NAD). This review explains the mechanisms by which induced ketosis might reduce mitochondrial dysfunction, inflammation, and oxidative stress in neuropsychiatric disorders and ameliorate abnormal levels of molecules and signaling pathways that also appear to contribute to the pathophysiology of these illnesses. This review also examines safety data relating to induced ketosis over the long term and discusses the design of future studies.

Identification of Secreted Phosphoprotein 1 (SPP1) as a Prognostic Factor in Lower-Grade Gliomas

OBJECTIVE

Secreted phosphoprotein 1 (SPP1) is an important extracellular glycoprotein that is associated with immune regulation, tumorigenesis, and cell signaling. However, the prognostic value of SPP1 in patients with glioma has not yet been clarified, especially in lower-grade gliomas. The objective of this study is to evaluate the prognostic merit of SPP1 in lower-grade gliomas.

METHODS

The messenger RNA (mRNA) expression of SPP1 in about 1000 cancer cell lines was explored by using the data from the Cancer Cell Line Encyclopedia database. The Oncomine database was mined to evaluate the mRNA expression of SPP1 in lower-grade glioma, glioblastoma, and normal brain tissues. The correlation between SPP1 mRNA expression and overall survival of patients with glioma from The Cancer Genome Atlas database was analyzed.

RESULTS

SPP1 mRNA expression of glioma was ranked as the eighth highest of all cancer cell lines in the Cancer Cell Line Encyclopedia database. The data from the Oncomine database suggested that SPP1 expression was significantly high in glioblastoma compared with normal brain tissues but was not significantly high in lower-grade glioma compared with normal brain tissue. Analysis of the RNA-Seq data from The Cancer Genome Atlas database showed that the increased SPP1 mRNA expression in lower-grade glioma was significantly associated with poor survival outcomes in patients with lower-grade glioma. Multivariate Cox regression analysis showed that SPP1 might be considered as an independent prognostic factor in lower-grade gliomas.

CONCLUSIONS

The present study showed that SPP1 overexpression is related to worse overall survival in patients with lower-grade glioma. Moreover, SPP1 could be considered as an independent factor in lower-grade gliomas.

The paramount role of cytokines and chemokines in papillary thyroid cancer: a review and experimental results

Our study demonstrates that (C-X-C motif) ligand 9 and 11 (CXCL9, CXCL11) chemokines were absent basally in non-neoplastic thyroid (TFC) and papillary thyroid carcinoma (PTC) cells. Interferon (IFN)γ induced the chemokine secretion in TFC and PTC, while tumor necrosis factor (TNF)α induced it only in PTC. IFNγ+TNFα induced a synergistic chemokines release in PTC, and at a lower level in TFC. Peroxisome proliferator-activated receptor (PPAR)γ agonists suppressed dose-dependently IFNγ+TNFα-induced chemokine release in TFC, while stimulated it in PTC. PPARγ knocking down, by RNA interference technique in PTC cells, abolished the effect of PPARγ agonists on chemokines release. In PTC cells, PPARγ agonists reduced proliferation, and CXCL9 or CXCL11 (100 and 500 pg/mL) reduced proliferation and migration (P < 0.01, for all). In conclusion, in PTC cells: (a) IFNγ+TNFα induced a marked release of CXCL9 and CXCL11; (b) PPARγ agonists stimulated CXCL9 and CXCL11 secretion, while inhibited proliferation; (c) CXCL9 and CXCL11 inhibited proliferation and migration. The use of CXCL9 or CXCL11 as antineoplastic agents in PTC remains to be explored. HIGHLIGHTS: • IFNγ and IFNγ+TNFα induce dose-dependently CXCL9 (and less CXCL11) in PTC cells. • Rosi and Pio dose-dependently inhibit the PTC cells proliferation. • Rosi and Pio (at variance of normal TFC) stimulate CXCL9 or CXCL11 secretion. • CXCL9 or CXCL11 induce a significant antiproliferative effect in PTC cells. • Chemokines induced by IFNγ (CXCL9 or CXCL11) inhibit migration in PTC cells.

The PPARγ Agonist Rosiglitazone Suppresses Syngeneic Mouse SCC (Squamous Cell Carcinoma) Tumor Growth through an Immune-Mediated Mechanism

Recent evidence suggests that PPARγ agonists may promote anti-tumor immunity. We show that immunogenic PDV cutaneous squamous cell carcinoma (CSCC) tumors are rejected when injected intradermally at a low cell number (1 × 106) into immune competent syngeneic hosts, but not immune deficient mice. At higher cell numbers (5 × 106 PDV cells), progressively growing tumors were established in 14 of 15 vehicle treated mice while treatment of mice with the PPARγ agonist rosiglitazone resulted in increased tumor rejection (5 of 14 tumors), a significant decrease in PDV tumor size, and a significant decrease in tumor cell Ki67 labeling. Rosiglitazone treatment had no effect on tumor rejection, tumor volume or PDV tumor cell proliferation in immune deficient NOD.CB17-PrkdcSCID/J mice. Rosiglitazone treatment also promoted an increase in tumor infiltrating CD3+ T-cells at both early and late time points. In contrast, rosiglitazone treatment had no significant effect on myeloid cells expressing either CD11b or Gr-1 but suppressed a late accumulation of myeloid cells expressing both CD11b and Gr-1, suggesting a potential role for CD11b+Gr-1+ myeloid cells in the late anti-tumor immune response. Overall, our data provides evidence that the PPARγ agonist rosiglitazone promotes immune-mediated anti-neoplastic activity against tumors derived from this immunogenic CSCC cell line.

CBP/p300 Drives the Differentiation of Regulatory T Cells through Transcriptional and Non-Transcriptional Mechanisms

Regulatory T cells (Treg) are immunosuppressive and negatively impact response to cancer immunotherapies. CREB-binding protein (CBP) and p300 are closely related acetyltransferases and transcriptional coactivators. Here, we evaluate the mechanisms by which CBP/p300 regulate Treg differentiation and the consequences of CBP/p300 loss-of-function mutations in follicular lymphoma. Transcriptional and epigenetic profiling identified a cascade of transcription factors essential for Treg differentiation. Mass spectrometry analysis showed that CBP/p300 acetylates prostacyclin synthase, which regulates Treg differentiation by altering proinflammatory cytokine secretion by T and B cells. Reduced Treg presence in tissues harboring CBP/p300 loss-of-function mutations was observed in follicular lymphoma. Our findings provide novel insights into the regulation of Treg differentiation by CBP/p300, with potential clinical implications on alteration of the immune landscape. SIGNIFICANCE: This study provides insights into the dynamic role of CBP/p300 in the differentiation of Tregs, with potential clinical implications in the alteration of the immune landscape in follicular lymphoma.

Immunoresolvents in asthma and allergic diseases: Review and update

Asthma and allergic diseases are inflammatory conditions developed by excessive reaction of the immune system against normally harmless environmental substances. Although acute inflammation is necessary to eradicate the damaging agents, shifting to chronic inflammation can be potentially detrimental. Essential fatty-acids-derived immunoresolvents, namely, lipoxins, resolvins, protectins, and maresins, are anti-inflammatory compounds that are believed to have protective and beneficial effects in inflammatory disorders, including asthma and allergies. Accordingly, impaired biosynthesis and defective production of immunoresolvents could be involved in the development of chronic inflammation. In this review, recent evidence on the anti-inflam]matory effects of immunoresolvents, their enzymatic biosynthesis routes, as well as their receptors are discussed.

Effect of particulate matter 2.5 on gene expression profile and cell signaling in JEG-3 human placenta cells

Particulate matter the environmental toxicant, with a diameter less than or equal to 2.5 μm (PM_2.5 ) is a common cause of several respiratory diseases. In recent years, several studies have suggested that PM_2.5 can influence diverse diseases, such as respiratory diseases, cardiovascular diseases, metabolic diseases, dementia, and female reproductive disorders, and unhealthy birth outcomes. In addition, several epidemiological studies have reported that adverse health effects of PM_2.5 can differ depending on regional variations. In the present study, to evaluate specific adverse health effects of PM_2.5 , we collected two different PM_2.5 samples from an underground parking lot and ambient air, and we evaluated cytotoxicity with eight different cell lines originating from human organs. Then, we selected JEG-3 human placenta cells, which show high cytotoxicity to both PM samples. Through RNA sequencing, gene expression profiling, and a gene ontology (GO) analysis of JEG-3 after exposure to two different PM_2.5 samples, we identified 1021 commonly expressed genes involved in immune responses, the regulation of apoptosis, and so forth, which are known to induce several adverse health effects. In addition, we identified genes related to the calcium-signaling pathway, steroid hormone biosynthesis, and the cytokine-cytokine receptor interaction through a Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Then, we confirmed these gene expressions using qRT-PCR, and the protein levels of mitogen-activated protein kinases and COX-2 with progesterone decreased using western blotting and enzyme-linked immunosorbent assay. In conclusion, this study suggests the possible toxic mechanism of human placenta that might be associated with PM_2.5 -induced female reproductive disorders.

Proliferation of prostate epithelia induced by IL-6 from stroma reacted with Trichomonas vaginalis

Benign prostatic hyperplasia (BPH) is characterized by the proliferation of stromal and epithelial cell types in the prostate, and interactions between the two types of cells. We demonstrated previously that proliferation of prostate stromal cells was induced by BPH epithelial cells in response to Trichomonas vaginalis (Tv) infection via crosstalk with mast cells. In this study, we investigated whether IL-6 released by the proliferating stromal cells in turn induce the BPH epithelial cells to multiply. When culture supernatants of the proliferating prostate stromal cells were added to BPH epithelial cells, the latter multiplied, and expression of cyclin D1, FGF2 and Bcl-2 increased. Blocking the IL-6 signalling pathway with anti-IL-6R antibody or JAK1/2 inhibitor inhibited the proliferation of the BPH epithelial cells and reduced the expression of IL-6, IL-6R and STAT3. Also, epithelial-mesenchymal transition was detected in the proliferating BPH epithelial cells. In conclusion, IL-6 released from proliferating prostate stromal cells induced by BPH epithelial cells infected with Tv in turn induces multiplication of the BPH epithelial cells. This result provides first evidence that the inflammatory microenvironment of prostate stromal cells resulting from Tv infection induces the proliferation of prostate epithelial cells by stromal-epithelial interaction.

Epidermal PPARγ influences subcutaneous tumor growth and acts through TNF-α to regulate contact hypersensitivity and the acute photoresponse

It is known that ultraviolet B (UVB) induces PPARγ ligand formation while loss of murine epidermal PPARγ (Pparg-/-^epi) promotes UVB-induced apoptosis, inflammation, and carcinogenesis. PPARγ is known to suppress tumor necrosis factor-α (TNF-α) production. TNF-α is also known to promote UVB-induced inflammation, apoptosis, and immunosuppression. We show that Pparg-/-^epi mice exhibit increased baseline TNF-α expression. Neutralizing Abs to TNF-α block the increased photo-inflammation and photo-toxicity that is observed in Pparg-/-^epi mouse skin. Interestingly, the increase in UVB-induced apoptosis in Pparg-/-^epi mice is not accompanied by a change in cyclobutane pyrimidine dimer clearance or in mutation burden. This suggests that loss of epidermal PPARγ does not result in a significant alteration in DNA repair capacity. However, loss of epidermal PPARγ results in marked immunosuppression using a contact hypersensitivity (CHS) model. This impaired CHS response was significantly alleviated using neutralizing TNF-α antibodies or loss of germline Tnf. In addition, the PPARγ agonist rosiglitazone reversed UVB-induced systemic immunosuppression (UV-IS) as well as UV-induced growth of B16F10 melanoma tumor cells in syngeneic mice. Finally, increased B16F10 tumor growth was observed when injected subcutaneously into Pparg-/-^epi mice. Thus, we provide novel evidence that epidermal PPARγ is important for cutaneous immune function and the acute photoresponse.

Oyster crude polysaccharides attenuates lipopolysaccharide-induced cytokines production and PPARγ expression in weanling piglets

This study evaluated whether oyster crude polysaccharides (OPS) attenuates lipopolysaccharide (LPS)-induced immune stress in weanling piglets. Thirty healthy crossbred piglets (28 ± 1 days old) were randomly divided into five groups (6 piglets/group). Blank control and LPS groups were fed with the basal diet, while low, medium and high dose of OPS groups were fed with the basal diet supplemented with 0.5, 0.8 and 1.2 % OPS, respectively, for 30 days. LPS group, as well as low, medium and high dose of OPS groups were then injected intraperitoneally with LPS (100 μg/kg body weight), whereas the blank control group was given phosphate buffered saline. The concentrations of TNF-α, IL-1β and IL-6 in plasma were detected by ELISA. The mRNA levels of PPARγ in liver, spleen, adrenal gland and thymus were evaluated by quantitative real-time PCR. The results showed that compared with the blank control, LPS treatment significantly increased plasma IL-1β, IL-6 and TNF-α levels, which was significantly attenuated by supplementing 0.5, 0.8 or 1.2 % OPS in the diet. In addition, LPS significantly induced expression of PPARγ mRNA in liver, spleen, adrenal gland, and thymus, which was blocked by adding OPS regardless of the doses. These results indicate that dietary supplementation of OPS was able to alleviate the immune stress induced by LPS.

Prognostic role of PPAR-γ and PTEN in the renal cell carcinoma

OBJECTIVE

To explore association of peroxisome proliferator-activated receptor gamma (PPAR-γ) and phosphatase and tensin homolog (PTEN) expressions with prognosis of renal cell carcinoma (RCC).

METHODS

Our study subjects included 87 RCC tissues, 28 paracarcinoma tissues and 21 normal renal tissues. PPAR-γ and PTEN detection was conducted using immunohistochemistry staining. The association of PPAR-γ and PTEN with the clinical parameters and prognosis of RCC was analyzed. Kaplan-Meier method and Cox's proportional hazards regression model were used for exploring the relation between variables and prognosis.

RESULTS

Among normal renal tissues, para-carcinoma tissues and renal cell carcinomas, positive PPAR-γ expression presented with a progressive tendency (P < 0.001), while positive PTEN expression a degressive tendency (P < 0.001). PPAR-γ expressions were closely related to tumor size, clinical stage and lymph node metastases (all P < 0.05). PTEN expressions were in close association with tumor size, Fuhrman grading, lymph node metastases (all P < 0.05). PPAR-γ expressions were in a negative relation with PTEN expressions (r = -0.417, P < 0.001). Negative PPAR-γ expressions confer a significantly higher overall survival rate than positive PPAR-γ expressions (P = 0.015), while negative PTEN expressions confer a significantly lower overall survival rate than positive PTEN expressions (P = 0.003). Clinical staging, Fuhrman grading, lymph node metastases, PPAR-γ and PTEN were independent prognostic factors for prognosis (all P < 0.05).

CONCLUSION

PPAR-γ and PTEN expressions are related to the clinical parameters and prognosis of RCC and may be a biomarker for prognosis of RCC.

The Omega-3 Fatty Acid Docosahexaenoic Acid Modulates Inflammatory Mediator Release in Human Alveolar Cells Exposed to Bronchoalveolar Lavage Fluid of ARDS Patients

BACKGROUND

This study investigated whether the 1 : 2 ω-3/ω-6 ratio may reduce proinflammatory response in human alveolar cells (A549) exposed to an ex vivo inflammatory stimulus (bronchoalveolar lavage fluid (BALF) of acute respiratory distress syndrome (ARDS) patients). Methods. We exposed A549 cells to the BALF collected from 12 ARDS patients. After 18 hours, fatty acids (FA) were added as docosahexaenoic acid (DHA, ω-3) and arachidonic acid (AA, ω-6) in two ratios (1 : 2 or 1 : 7). 24 hours later, in culture supernatants were evaluated cytokines (TNF-α, IL-6, IL-8, and IL-10) and prostaglandins (PGE2 and PGE3) release. The FA percentage content in A549 membrane phospholipids, content of COX-2, level of PPARγ, and NF-κB binding activity were determined.

RESULTS

The 1 : 2 DHA/AA ratio reversed the baseline predominance of ω-6 over ω-3 in the cell membranes (P < 0.001). The proinflammatory cytokine release was reduced by the 1 : 2 ratio (P < 0.01 to <0.001) but was increased by the 1 : 7 ratio (P < 0.01). The 1 : 2 ratio reduced COX-2 and PGE2 (P < 0.001) as well as NF-κB translocation into the nucleus (P < 0.01), while it increased activation of PPARγ and IL-10 release (P < 0.001). Conclusion. This study demonstrated that shifting the FA supply from ω-6 to ω-3 decreased proinflammatory mediator release in human alveolar cells exposed to BALF of ARDS patients.

Involvement of glucocorticoid receptor activation on anti-inflammatory effect induced by peroxisome proliferator-activated receptor γ agonist in mice

Glucocorticoids are effective anti-inflammatory agents widely used for the treatment of acute and chronic inflammatory diseases. Recent in vitro studies have proposed that glucocorticoid receptor (GR) activation is involved in peroxisome proliferator-activated receptor γ (PPARγ) agonist-induced effects. In this study, to examine the involvement of the GR in PPARγ agonist- and retinoid X receptor (RXR) agonist-mediated anti-inflammatory effects in vivo, we tested the anti-inflammatory effects of dexamethasone (a GR agonist) with pioglitazone (a PPARγ agonist) or 6-[N-ethyl-N-(3-isopropoxy-4-isopropylphenyl)-amino] nicotinic acid (NEt-3IP; an RXR agonist) by using an experimental model of carrageenan-induced inflammation. We also evaluated the effects of a GR antagonist on PPARγ agonist- or RXR agonist-induced anti-inflammatory effects. Results showed that the GR antagonist RU486 reduced the anti-inflammatory effects of GR or PPARγ agonists but not those of the RXR agonist. In addition, combinations of GR and PPARγ agonists or GR and RXR agonists had no effect on carrageenan-induced paw edema. Moreover, the PPARγ antagonist GW9662 and RXR antagonist 6-[N-4-(trifluoromethyl)-benzenesulfonyl-N-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-2-naphthyl)-amino] nicotinic acid (NS-4TF) had no effect on the anti-inflammatory effect of the GR agonist dexamethasone. Therefore, it is suggested that GR activation in vivo does not play a direct role in PPARγ/RXR heterodimer signaling. In contrast, pioglitazone showed a partial anti-inflammatory effect via GR activation. These data provide evidence for the pro-inflammatory activity of pioglitazone.

Induction of Wnt-inducible signaling protein-1 correlates with invasive breast cancer oncogenesis and reduced type 1 cell-mediated cytotoxic immunity: a retrospective study

Innate and type 1 cell-mediated cytotoxic immunity function as important extracellular control mechanisms that maintain cellular homeostasis. Interleukin-12 (IL12) is an important cytokine that links innate immunity with type 1 cell-mediated cytotoxic immunity. We recently observed in vitro that tumor-derived Wnt-inducible signaling protein-1 (WISP1) exerts paracrine action to suppress IL12 signaling. The objective of this retrospective study was three fold: 1) to determine whether a gene signature associated with type 1 cell-mediated cytotoxic immunity was correlated with overall survival, 2) to determine whether WISP1 expression is increased in invasive breast cancer, and 3) to determine whether a gene signature consistent with inhibition of IL12 signaling correlates with WISP1 expression. Clinical information and mRNA expression for genes associated with anti-tumor immunity were obtained from the invasive breast cancer arm of the Cancer Genome Atlas study. Patient cohorts were identified using hierarchical clustering. The immune signatures associated with the patient cohorts were interpreted using model-based inference of immune polarization. Reverse phase protein array, tissue microarray, and quantitative flow cytometry in breast cancer cell lines were used to validate observed differences in gene expression. We found that type 1 cell-mediated cytotoxic immunity was correlated with increased survival in patients with invasive breast cancer, especially in patients with invasive triple negative breast cancer. Oncogenic transformation in invasive breast cancer was associated with an increase in WISP1. The gene expression signature in invasive breast cancer was consistent with WISP1 as a paracrine inhibitor of type 1 cell-mediated immunity through inhibiting IL12 signaling and promoting type 2 immunity. Moreover, model-based inference helped identify appropriate immune signatures that can be used as design constraints in genetically engineering better pre-clinical models of breast cancer.

Effective anti-tumor immunity is proportional to the number and to the cytotoxic activity of immune cells that enter the tumor microenvironment. Recent advances in cancer immunotherapy stem from increasing the number of tumor-infiltrating immune cells by inhibiting immune checkpoints or adoptive T cell therapy. Here, we used computational methods to identify potential mechanisms present within the tumor microenvironment that limit the efficacy of anti-tumor immunity. Specifically, we found that oncogenic transformation is associated with the induction of tumor-derived biochemical cues, namely Wnt-inducible signaling protein-1, that locally suppress anti-tumor immunity. Moreover, we used model-based inference to demonstrate that a gene signature consistent with effective type 1 cell-mediated cytotoxic immunity is a predictor of overall survival independent of molecular pathology. Interestingly, patients with triple negative breast cancer were more enriched in the cohort associated with type 1 cell-mediated immunity. As this immune gene signature is not present in current genetically engineered mouse models of breast cancer, the results help identify design constraints for engineering better pre-clinical models of breast cancer. Demonstrating efficacy in pre-clinical animal models is a pre-requisite for bringing improved cancer immunotherapies into the clinic.

Use of Pioglitazone in Patients with Lichen Planopilaris

Background:

Recent basic science research has revealed a decreased tissue expression of peroxisome proliferator-activated receptor (PPAR) γ in lichen planopilaris (LPP). Therefore, thiazolidinediones, being PPARγ agonists, could be used to treat LPP.

Methods:

We followed 24 patients with LPP who were treated with oral pioglitazone hydrochloride. Improvement in LPP was defined as a decrease in or disappearance of symptoms and perifollicular erythema in the context of halted spread of old patches.

Results:

Twenty of 24 patients were females. The average age was 52.5 years, and ages ranged from 22 to 70 years. Five of 24 patients have achieved remission; improvement was noted in half of the patients; there was no change in 3 patients; and 4 patients discontinued treatment due to side effects. Side effects were mild and included left calf pain, lightheadedness and nausea, dizziness, and hives.

Conclusion:

Use of thiazolidinediones might be a new promising venue of LPP treatment.

Involvement of the Retinoid X Receptor Ligand in the Anti-Inflammatory Effect Induced by Peroxisome Proliferator-Activated Receptor γ Agonist In Vivo

Peroxisome proliferator-activated receptor γ (PPARγ) forms a heterodimeric DNA-binding complex with retinoid X receptors (RXRs). It has been reported that the effect of the PPAR agonist is reduced in hepatocyte RXR-deficient mice. Therefore, it is suggested that the endogenous RXR ligand is involved in the PPARγ agonist-induced anti-inflammatory effect. However, the participation of the RXR ligand in the PPARγ-induced anti-inflammatory effect is unknown. Here, we investigated the influence of RXR antagonist on the anti-inflammatory effect of PPARγ agonist pioglitazone in carrageenan test. In addition, we also examined the influence of PPAR antagonist on the anti-inflammatory effect induced by RXR agonist NEt-3IP. The RXR antagonist suppressed the antiedema effect of PPARγ agonist. In addition, the anti-inflammatory effect of RXR agonist was suppressed by PPARγ antagonist. PPARγ agonist-induced anti-inflammatory effects were reversed by the RXR antagonist. Thus, we showed that the endogenous RXR ligand might contribute to the PPARγ agonist-induced anti-inflammatory effect.

Anticancer Role of PPARgamma Agonists in Hematological Malignancies Found in the Vasculature, Marrow, and Eyes

The use of targeted cancer therapies in combination with conventional chemotherapeutic agents and/or radiation treatment has increased overall survival of cancer patients. However, longer survival is accompanied by increased incidence of comorbidities due, in part, to drug side effects and toxicities. It is well accepted that inflammation and tumorigenesis are linked. Because peroxisome proliferator-activated receptor (PPAR)-gamma agonists are potent mediators of anti-inflammatory responses, it was a logical extension to examine the role of PPARgamma agonists in the treatment and prevention of cancer. This paper has two objectives: first to highlight the potential uses for PPARgamma agonists in anticancer therapy with special emphasis on their role when used as adjuvant or combined therapy in the treatment of hematological malignancies found in the vasculature, marrow, and eyes, and second, to review the potential role PPARgamma and/or its ligands may have in modulating cancer-associated angiogenesis and tumor-stromal microenvironment crosstalk in bone marrow.

Peroxisome proliferator-activated receptor (PPAR): balance for survival in parasitic infections

Parasitic infections induce a magnitude of host responses. At the opposite ends of the spectrum are those that ensure the host's needs to eliminate the invaders and to minimize damage to its own tissues. This review analyzes how parasites would manipulate immunity by activating the immunosuppressive nuclear factor, peroxisome proliferator-activated receptors (PPARs) with type 2 cytokines and free fatty acids from arachidonic acid metabolism. PPARs limit the action of type 1 immunity, in which classically activated macrophages act through the production of proinflammatory signals, to spare the parasites. They also favor the development of alternately activated macrophages which control inflammation so the host would not be destroyed. Possibly, the nuclear factors hold a pivotal role in the establishment of chronic infection by delicately balancing the pro- and anti-inflammatory signaling mechanisms and their ligands may be used as combination therapeutics to limit host pathology.

Transportation stress alters the expression of immunoregulatory cytokines in the porcine thymus

This study investigated the effects of transportation stress on blood concentrations of the main pro-inflammatory cytokines (interleukins IL-1β, IL-2 and IL-6; tumour necrosis factor-α) and anti-inflammatory cytokines (IL-4 and IL-10) and the expression of these cytokines and their receptors in the thymus. Pigs were assessed after 1, 2 and 4 h of transportation (n=5 per group), with normal housing conditions as a control (n=4). Serum concentrations of IL-2, IL-6 and IL-10 were highest at 1 h, whereas concentrations of IL-6 and IL-10 were significantly decreased at 4h. Expression of these three cytokines and their receptors was also significantly altered in the thymus during transportation stress. Serum IL-10 concentrations and thymus IL-10 mRNA expression were significantly correlated. The thymus may contribute towards the regulation of cytokines in pigs during transportation.

Metabolic syndrome and cancer

Since its first description by Reavan in 1988, accepted criteria for clinical identification of the components of metabolic syndrome have been promulgated by the National Cholesterol Education Program/Adult Treatment Panel III (NCEP/ATP III) and the World Health Organization (WHO) as well as the International Diabetes Federation (IDF), and the American Association of Clinical Endocrinologists (AACE). Insulin resistance is a common metabolic abnormality underlying type 2 diabetes mellitus and is also an independent risk factor for cardiovascular disease. Although ATP III identified cardiovascular disease (CVD) as the primary clinical outcome of the metabolic syndrome, we now have evidence that metabolic syndrome is associated with type 2 diabetes mellitus, polycystic ovarian disease, nonalcoholic fatty liver disease, and possibly some cancers. This review summarizes evidence in support of the relationship between metabolic syndrome and various cancers and possible underlying mechanisms and therapeutic interventions.

Monokine induced by interferon gamma (IFNgamma) (CXCL9) and IFNgamma inducible T-cell alpha-chemoattractant (CXCL11) involvement in Graves' disease and ophthalmopathy: modulation by peroxisome proliferator-activated receptor-gamma agonists

CONTEXT

CXC alpha-chemokine CXCL10/IP-10 plays an important role in the initial phases of Graves' ophthalmopathy (GO). Human thyrocytes, orbital fibroblasts, and preadipocytes are stimulated to produce CXCL10 when treated with interferon gamma (IFNgamma) and TNFalpha. Peroxisome proliferator-activated receptor-gamma (PPARgamma) activation plays an inhibitory role in this process.

OBJECTIVE

Until now, no data are present in literature about the involvement of CXCL9 and CXCL11 in Graves' disease and GO, or of PPARgamma activators' effect on these chemokines.

METHODS

It has been studied how IFNgamma and TNFalpha stimulation and PPARgamma activation affect CXCL9 and CXCL11 secretion in primary cultures of thyrocytes, orbital fibroblasts, and preadipocytes.

RESULTS

In primary cultures of thyrocytes, retrobulbar fibroblasts, and retrobulbar preadipocytes obtained from GO patients, CXCL9 and CXCL11 production was absent under basal conditions; CXCL9 and CXCL11 secretion was not induced by TNFalpha alone, whereas it was dose dependently stimulated treating cells with IFNgamma. The treatment with TNFalpha plus IFNgamma has a synergistic effect on CXCL9 and CXCL11 release. Treating all cell types with the PPARgamma agonist, rosiglitazone, or pioglitazone, the IFNgamma plus TNFalpha-induced CXCL9 and CXCL11 release was dose dependently (0.1-20 microm) suppressed.

CONCLUSIONS

We conclude that thyrocytes and retrobulbar cell types from patients with Graves' disease and ophthalmopathy participate in the self-perpetuation of inflammation, releasing CXCL9 and CXCL11 chemokines when stimulated with cytokines. PPARgamma activation plays an inhibitory role in this process. The huge response of CXCL9 to the IFNgamma plus TNFalpha-stimulation suggests its leading role among CXC chemokines.

PPARs Mediate Lipid Signaling in Inflammation and Cancer

Lipid mediators can trigger physiological responses by activating nuclear hormone receptors, such as the peroxisome proliferator-activated receptors (PPARs). PPARs, in turn, control the expression of networks of genes encoding proteins involved in all aspects of lipid metabolism. In addition, PPARs are tumor growth modifiers, via the regulation of cancer cell apoptosis, proliferation, and differentiation, and through their action on the tumor cell environment, namely, angiogenesis, inflammation, and immune cell functions. Epidemiological studies have established that tumor progression may be exacerbated by chronic inflammation. Here, we describe the production of the lipids that act as activators of PPARs, and we review the roles of these receptors in inflammation and cancer. Finally, we consider emerging strategies for therapeutic intervention.