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To show that MRTF-A localization was dependent on F-actin dynamics, we stimulated SK-Mel-19 cells with 20% FBS to induce stress fiber formation which induced MRTF-A nuclear localization. We also treated SK-Mel-147 cells with latrunculin B which inhibits F-actin formation and MRTF-A relocated to the cytosol.

The Cancer Genome Atlas (TCGA) cutaneous melanoma dataset was stratified into quartiles based upon expression of indicated genes. Kaplan-Meier plots were generated from the highest (grey) and lowest (black) expressing quartiles. Survival curves were analyzed with the log-rank test with a cutoff of P < 0.05 as statistically significant.

To test the effect of two dietary antioxidants: butylated hydroxytoluene (BHT) and 3-hydroxytyrosol (3-HT) in experimental food allergy.BALB/c mice maintained on control diet or diet with BHT or 3-HT were sensitized with ovalbumin (OVA) or saline through transdermal exposure. Plasma OVA-specific IgE (OVA-IgE) and IgG1 (OVA-IgG1) antibody levels were determined using ELISA. Sensitized mice were challenged by oral gavage with OVA. Rectal temperature (RT) was measured before and after challenge. Mast cell degranulation was quantified by measuring the plasma levels of mouse mucosal mast cell protease-1 (mMCP-1). Flow cytometry was carried out to evaluate the percentage Th2 cells from the spleen.Mice on either a 3-HT or BHT diet showed a significantly decreased IgE response to OVA sensitization and less severe anaphylaxis, as evidenced by a diminished drop in body temperature, attenuated clinical signs, a more rapid recovery and decreased mast cell degranulation (as determined by lower plasma mMCP-1 levels).The present study indicates two dietary antioxidants: BHT and 3-HT may be protective against experimental food allergy. These results suggest 3-HT and BHT could potentially be useful for prevention of food allergy.

There are considerable data to suggest an association between inflammation and cardiovascular disease, including a link between the immune system and hypertension. Our previous studies indicated an increase in the induction of proinflammatory cytokines by activated T cells cultured in media conditioned with perivascular adipose tissue (PVAT) taken from Dahl S rats on a high fat diet (HFD). Notably this effect preceded the development of hypertension in these animals. The purpose of the present studies was to test the hypothesis that high fat diet promotes inflammatory gene expression in immune cells in mesenteric PVAT and mesenteric lymph nodes (mLN) of Dahl S rats prior to the development of hypertension. To test this hypothesis, we isolated the stromal vascular fraction (SVF) from mPVAT and cells from mLN from Dahl S rats on high fat diet for 10 weeks for single cell RNA-sequencing analysis. In the mPVAT SVF we found an increase in the expression of acute inflammatory genes, including Tnfa , and genes associated with T cell chemotaxis, such as Cxcr3 and Cxcl11 . Conversely, there was also an increase in genes that negatively regulate immune response and adipokine expression in mPVAT SVF from Dahl S rats on HFD. In mLN, we found an increase in genes associated with IL-3 signaling in CD8 T cells and in genes associated with NFκB signaling in CD4 T cells (Fig. 1). Taken together, these data suggest an increase in acute inflammatory signaling in cells in mPVAT and mLN from Dahl S rats on HFD.

Arsenic is a persistent environmental contaminant that humans are exposed to primarily through contaminated water supplies. Arsenic has been shown to have numerous immunomodulatory effects, including deleterious effects on T cell function. However, the effect of arsenic on human T cell function in the context of influenza infection remains poorly characterized. The goal of this study was to determine the effects of arsenic on T cell activation and effector function in a human-relevant ex vivo model with influenza challenge. Flow cytometric analysis of T cells following the treatment of primary human peripheral blood mononuclear cells with environmentally relevant concentrations of arsenic trioxide and subsequent challenge with influenza A virus showed reduced viability, alterations in activation, a reduction in the population of memory cells, and reduced effector function evidenced by decreased IFNγ and granzyme B production. Overall, these studies suggest that arsenic impairs the human T cell response to influenza which corroborates epidemiological findings and could have further implications for antiviral immunity and vaccine efficacy.

Background and AimsIn severe cases of acetaminophen (APAP) overdose, acute liver injury rapidly progresses to acute liver failure (ALF), producing life-threatening complications including, hepatic encephalopathy (HE) and multi-organ failure (MOF). Systemic levels of interleukin-6 (IL-6) and IL-10 are highest in ALF patients with the most severe complications and the poorest prognosis. The mechanistic basis for dysregulation of these cytokines, and their association with outcome in ALF, remain poorly defined.MethodsTo investigate the impact of IL-6 and IL-10 in ALF, we used an experimental setting of failed liver repair after APAP overdose in which a high dose of APAP is administered (i.e., 500-600 mg/kg). Mice were treated with neutralizing antibodies to block IL-6 and IL-10.ResultsIn mice with APAP-induced ALF, high levels of IL-10 reduced monocyte recruitment and trafficking in the liver resulting in impaired clearance of dead cell debris. Kupffer cells in these mice, displayed features of myeloid-derived suppressor cells, including high level expression of IL-10 and PD-L1, which were increased in an IL-6-dependent manner. Similar to ALF patients with HE, cerebral blood flow was reduced in mice with APAP-induced ALF. Remarkably, although IL-6 is hepatoprotective in mice treated with low doses of APAP (i.e., 300 mg/kg), IL-6 neutralization in mice with APAP-induced ALF fully restored cerebral blood flow and reduced mortality.ConclusionCollectively, these studies demonstrate that exaggerated production of IL-6 in APAP-induced ALF triggers immune suppression (i.e., high levels of IL-10 and PD-L1), reduces cerebral blood flow (a feature of hepatic encephalopathy), disrupts liver repair (i.e., failed clearance of dead cells), and increases mortality.

There is considerable evidence for a causative role for T cells in hypertension, including studies with immunosuppressive drugs and T cell-deficient models. Our previous studies showed that soluble mediators from mesenteric perivascular adipose tissue (mPVAT) modulate T cell function. Specifically, conditioned media from mPVAT (mPVAT-CM) from Dahl S rats on a high fat diet (HFD) promoted expression of the pro-inflammatory cytokines, IFNg, IL-17a and GM-CSF, by activated T cells. Furthermore, the Dahl S rats on HFD will later develop hypertension. Hypothesis: mPVAT is stimulated to produce immunomodulatory mediators that promotes Th1/17 differentiation preceding the development of HFD-induced hypertension. We conducted bulk RNA-seq on activated splenocytes cultured in mPVAT-CM from Dahl S rats on either control or HFD for 10 weeks. In accordance with our previous studies, PVAT-CM from HFD-fed rats significantly upregulated many genes associated with IFNg/IL-17 induction, including Mpeg1, Lyz2 and Tnfsf4 (5.0±1.78, 3.70±0.53 and 1.78±0.42 fold over Control diet, respectively). In contrast, Th2/Treg-associated genes, such as Ctla2a (-0.27±0.02) and Ccr4 (-0.41±0.03) were downregulated. We also performed single cell (sc) RNA-seq on the PVAT stromal vascular fraction (SVF) and found that acute inflammatory genes were enriched in the HFD group. Together with the bulk RNA-seq on mPVAT, these data strongly suggest that the pro-inflammatory mPVAT micro-environment may promote Th1/Th17 differentiation. To identify mediators in PVAT-CM that may induce Th1/Th17 differentiation, we compared the bulk RNA-seq on splenocytes cultured in PVAT-CM with bulk RNA-seq conducted on the whole mPVAT itself. We found that a T cell co-stimulatory receptor DPP4 (CD26), which is closely associated with T cell activation was significantly increased in mPVAT from HFD-fed rats (33.4±2.3 HFD vs. 15.3±1.8 Control diet). We also observed an increase in DPP4 global expression from mPVAT SVF in HFD-fed rats, as determined by scRNA-seq. Conclusion: The data suggest that HFD promotes the IFNg and IL-17a pathways in PVAT, which precedes hypertension in Dahl S rats and correlates with an increase in expression of DPP-4, a gene that promotes T cell activation. (NIH P01 HL070687).

Nrf2 is a cytoprotective transcription factor which is involved in ameliorating oxidative stress and toxic insults. Recently, an immunomodulatory role for Nrf2 has gained appreciation as it has been shown to protect cells and hosts alike in a variety of immune and inflammatory disorders. However, Nrf2 utilizes numerous distinct pathways to elicit its immunomodulatory effects. In this review, we summarize the literature discussing the roles of Nrf2 in autoimmunity and infectious diseases with a goal of understanding the potential to therapeutically target Nrf2.

Nuclear factor erythroid-derived 2-like 2 (Nrf2) is a stress-activated transcription factor that is highly responsive to oxidative stress and electrophilic stimuli. Upon activation, Nrf2 upregulates a battery of cytoprotective genes meant to prevent cell death or damage. In many models of inflammation, Nrf2 protects against the immune response and decreases injury, including in the context of asthma and allergy. However, in some models of asthma and allergy, Nrf2 either does not play a role or can even exacerbate inflammation. In general, the reasons behind these discrepancies are not clear and the mechanisms by which Nrf2 modulates immune response are largely uncharacterized. The aim of this review is to highlight current literature assessing the role of Nrf2 in allergy and asthma to understand Nrf2 as a potential therapeutic target. SIGNIFICANCE STATEMENT: Nuclear factor erythroid-derived 2-like 2 (Nrf2) is an important immune mediator that modulates numerous immune cell types in various inflammatory diseases, including allergy and asthma. There is considerable interest in Nrf2 as a drug target in inflammation, which is complicated by the complex nature of Nrf2 in the immune system. This review focuses on the role of Nrf2 in asthma and allergy, including in regulating immune cell function and in detoxifying xenobiotics that exacerbate these diseases.

Nrf2 is a cytoprotective transcription factor which is involved in ameliorating oxidative stress and toxic insults. Recently, an immunomodulatory role for Nrf2 has gained appreciation as it has been shown to protect cells and hosts alike in a variety of immune and inflammatory disorders. However, Nrf2 utilizes numerous distinct pathways to elicit its immunomodulatory effects. In this review, we summarize the literature discussing the roles of Nrf2 in autoimmunity and infectious diseases with a goal of understanding the potential to therapeutically target Nrf2.

Perivascular adipose tissue (PVAT) may connect adiposity to hypertension because of its functions and proximity to blood vessels. Immune cells in adipose tissue are proposed to couple adiposity to hypertension development in a sex-specific fashion. It is unknown if sex-differences exist in PVAT’s immune community during the onset of adiposity-induced hypertension. Both sexes of the Dahl S rat strain become equally hypertensive (table) when fed a high fat (HFD) diet. We hypothesized that both sexes have similar immune cell composition in PVAT with the development and progression of HFD-induced hypertension. Male and female Dahl S rats were fed a regular (10% calories from fat; CD) diet or a HFD (60%) from weaning. Thoracic aorta PVAT (APVAT) was harvested at 10 (pre-hypertension), 17 (onset) or 24 (chronic) weeks (w) of diet. Macrophages (subtypes), neutrophils, mast, T (subtypes), B, NK cells were measured by flow cytometry. At 10 w, HFD females had 5X the number of M1-like macrophages vs HFD males. At 17 w, CD females had 10X the number of M2-like macrophages vs CD males. At 17 w and 24 w, males had greater number of CD4 (2X) and CD8 (1.5X) memory T cells vs females, independent of the diet (table). In summary, sex-differences in M1-like macrophage counts in APVAT precedes the development of HFD-induced hypertension in Dahl S rats. The progression of hypertension is associated with memory T cells in males and M2-like macrophages in females. This study is foundational to understand the sex-specific roles of these immune cells in regulating vascular tone in HFD-induced hypertension, underscoring the need for novel sex-specific anti-hypertensive immune modulators.

Cadmium is a toxic metal and common environmental contaminant. Chronic cadmium exposure results in kidney, bone, reproductive, and immune toxicity as well as cancer. Cadmium induces splenomegaly and affects the adaptive immune system, but specific effects vary depending on the dose, model, and endpoint. This study investigates the effects of subchronic, oral, and low-dose cadmium exposure (32 ppm cadmium chloride in drinking water for 10 weeks) on the rat immune system, focusing on T cell function. Cadmium-exposed animals demonstrated slight increases in the spleen-to-body weight ratios, and decreases in overall splenic cell numbers and markers of oxidative stress. The relative ratios of splenic cell populations remained similar, except for modest increases in regulatory T cells in the cadmium-exposed animals. Cadmium exposure also significantly increased the production of IFNγ, a pro-inflammatory cytokine, and IL-10, a cytokine produced by multiple T cell subsets that typically inhibits IFNγ expression, by activated T cells. The increase in IFNγ and IL-10 suggests that cadmium exposure may affect multiple T cell subsets. Collectively, this study suggests that subchronic, low-dose cadmium exposure impacts both immune cell function and cellularity, and may enhance inflammatory responses.

Aims: Activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway in normal cells inhibits carcinogenesis, whereas constitutive activation of Nrf2 in cancer cells promotes tumor growth and chemoresistance. However, the effects of Nrf2 activation in immune cells during lung carcinogenesis are poorly defined and could either promote or inhibit cancer growth. Our studies were designed to evaluate tumor burden and identify immune cell populations in the lungs of Nrf2 knockout (KO) versus wild-type (WT) mice challenged with vinyl carbamate. Results: Nrf2 KO mice developed lung tumors earlier than the WT mice and exhibited more and larger tumors over time, even at late stages. T cell populations were lower in the lungs of Nrf2 KO mice, whereas tumor-promoting macrophages and myeloid-derived suppressor cells were elevated in the lungs and spleen, respectively, of Nrf2 KO mice relative to WT mice. Moreover, 34 immune response genes were significantly upregulated in tumors from Nrf2 KO mice, especially a series of cytokines (Cxcl1, Csf1, Ccl9, Cxcl12, etc.) and major histocompatibility complex antigens that promote tumor growth. Innovation: Our studies discovered a novel immune signature, characterized by the infiltration of tumor-promoting immune cells, elevated cytokines, and increased expression of immune response genes in the lungs and tumors of Nrf2 KO mice. A complementary profile was also found in lung cancer patients, supporting the clinical significance of our findings. Conclusion: Overall, our results confirmed a protective role for Nrf2 in late-stage carcinogenesis and, unexpectedly, suggest that activation of Nrf2 in immune cells may be advantageous for preventing or treating lung cancer.

Tert-butylhydroquinone (tBHQ) is a commonly used food preservative with known immunomodulatory activity; however, there is little information regarding its role on natural killer (NK) cell activation and function. tBHQ is a known activator of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), which results in induction of cytoprotective genes. Activation of Nrf2 has been shown to modulate immune responses in a number of different models. In addition, studies in our laboratory have shown that tBHQ inhibits numerous early events following T cell activation. In the current study, we investigated whether activated NK cells are impacted by tBHQ, since many signaling cascades that control NK cell effector function also contribute to T cell function. Splenocytes were isolated from female, wild-type C57Bl/6J mice and treated with 1 μM or 5 μM tBHQ. NK cell function was assessed after activation with phorbol 12-myristate 13-acetate (PMA) and ionomycin for 24 h. Activation of NK cells in the presence of tBHQ decreased total NK cell percentage, production of intracellular interferon gamma (IFNƔ), granzyme B, and perforin, and induction of the cell surface proteins CD25 and CD69, which are markers of NK cell activation. In addition to NK cell effector function, NK cell maturation was also altered in response to tBHQ. Notably, this is the first study to demonstrate that the Nrf2 activator, tBHQ, negatively impacts effector function and maturation of NK cells.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces hepatic oxidative stress following activation of the aryl hydrocarbon receptor (AhR). Our recent studies showed TCDD induced pyruvate kinase muscle isoform 2 (Pkm2) as a novel antioxidant response in normal differentiated hepatocytes. To investigate cooperative regulation between nuclear factor, erythroid derived 2, like 2 (Nrf2) and the AhR in the induction of Pkm2, hepatic chromatin immunoprecipitation sequencing (ChIP-seq) analyses were integrated with RNA sequencing (RNA-seq) time-course data from mice treated with TCDD for 2-168 hours. ChIP-seq analysis 2 hours after TCDD treatment identified genome-wide NRF2 enrichment. Approximately 842 NRF2-enriched regions were located in the regulatory region of differentially expressed genes (DEGs), whereas 579 DEGs showed both NRF2 and AhR enrichment. Sequence analysis of regions with overlapping NRF2 and AhR enrichment showed over-representation of either antioxidant or dioxin response elements, although 18 possessed both motifs. NRF2 exhibited negligible enrichment within a closed Pkm chromatin region, whereas the AhR was enriched 29-fold. Furthermore, TCDD induced Pkm2 in primary hepatocytes from wild-type and Nrf2-null mice, indicating NRF2 is not required. Although NRF2 and AhR cooperate to regulate numerous antioxidant gene expression responses, the induction of Pkm2 by TCDD is independent of reactive oxygen species-mediated NRF2 activation.

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a stress-activated transcription factor activated by stimuli such as electrophilic compounds and other reactive xenobiotics. Previously, we have shown that the commonly used food additive and Nrf2 activator tert-butylhydroquinone (tBHQ) suppresses interleukin-2 (IL-2) production, CD25 expression, and NFκB activity in human Jurkat T cells. The purpose of the current studies was to determine whether these effects were dependent upon Nrf2 by developing a human Nrf2-null T cell model using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 technology. The current studies show that suppression of CD25 expression by tBHQ is partially dependent on Nrf2, whereas inhibition of IL-2 secretion is largely Nrf2-independent. Interestingly, tBHQ inhibited NFκB activation in an Nrf2-independent manner. This was an unexpected finding since Nrf2 inhibits NFκB activation in other models. These results led us to investigate another more potent Nrf2 activator, the synthetic triterpenoid 1[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im). Treatment of wild-type and Nrf2-null Jurkat T cells with CDDO-Im resulted in an Nrf2-dependent suppression of IL-2. Furthermore, susceptibility to reactive oxygen species was significantly enhanced in the Nrf2-null clones as determined by decreased mitochondrial membrane potential and cell viability. Importantly, this study is the first to describe the generation of a human Nrf2-null model, which is likely to have multiple applications in immunology and cancer biology. Collectively, this study demonstrates a role for Nrf2 in the effects of CDDO-Im on CD25 and IL-2 expression, whereas the effect of tBHQ on these parameters is complex and likely involves modulation of multiple stress-activated transcription factors, including NFκB and Nrf2.

There is considerable evidence for a role for the immune system in the development of hypertension, however the exact nature of this role is currently being characterized. Specifically, T cells have been identified as one of the immune cell types that contributes to hypertension. Our previous studies demonstrated that mesenteric perivascular adipose tissue (mPVAT) harbors a large T cell population. In the present study, we tested the hypothesis that soluble mediators in mPVAT influence T cell function during hypertension. Toward this end, we utilized a unique model of hypertension in which Dahl S rats on a high fat/high calorie diet develop hypertension by 17 weeks of age, whereas Dahl S rats on normal rodent chow do not. We found that conditioned media from mPVAT from Dahl S rats on a high fat diet markedly increased activated T cell production of the pro-inflammatory cytokines, GM-CSF, IFNγ and IL-17a as compared to cytokine production by T cells cultured in mPVAT-conditioned media from rats on normal control chow (Table 1). These cytokines would be expected to cause pleiotropic inflammatory effects, including increasing the numbers and activation of macrophages and neutrophils, among other effects. Conversely, the anti-inflammatory cytokine, IL-10, was not different between the groups, suggesting the effect is selective for inflammatory cytokines. Taken together, these data strongly suggest soluble mediators from PVAT influence T cell inflammatory status early during the development of hypertension triggered by high fat diet. Overall, the data provide evidence for a role for T cells in high fat diet-associated hypertension. (This study was supported by NIH grant P01 HL070687)

Perivascular adipose tissue (PVAT) is protective and reduces the contraction of blood vessels in health. Eosinophils are one of the key players to the anti-contractile nature of PVAT in health. This finding led to our hypothesis that an ‘active’ immune complement exists in healthy PVAT. Male and female Sprague Dawley rats (12-14 weeks age) were used. PVATs from the thoracic aorta (brown APVAT), mesenteric resistance vessels (white MRPVAT), non-PVATs: subscapular (brown SS fat), retroperitoneal (white RP fat) and spleen (positive control) were harvested from each animal. T cells (CD4 and CD8), B cells, NK cells, macrophages, mast cells and neutrophils in the stromal vascular fraction were quantified using 9-color flow cytometry. Activation status (effector/ memory/ regulatory) of macrophages, T and B cells were also determined by flow cytometry. The number of immune cells are normalized to tissue weight (table). MRPVAT has denser total immune population (both sexes) and active macrophage pool (females) vs RP fat. APVAT homes a denser immune niche (females) and active T cell, B cell pools (both sexes) vs SS fat. This is the first study to characterize ‘active’ immune populations in healthy PVATs vs non-PVATs in male and female rats. Further studies to understand the functions of basally active immune cells in healthy PVATs are warranted.

OBJECTIVES: We examined the effects of the food preservative, tert-Butylhydroquinone (tBHQ), on natural killer (NK) cells when infected with influenza in C57Bl/6 mice. Previously, we found tBHQ to negatively impact splenic NK cell effector function in vitro. Therefore, we hypothesized that the consumption of tBHQ would impair the NK cell response against a primary influenza virus infection. METHODS: Female, C57Bl/6 mice were fed either a diet containing 0.0014% tBHQ or a control diet two weeks prior to infection. Mice were instilled intranasally with 21.78 HAU of influenza A/PR/8/34 (H1N1) and were monitored for two days. Body weight was recorded as a measurement for infection. After day two of infection, lungs were collected and processed for analysis by flow cytometry, enzyme-linked immunosorbent assay (ELISA), and total antioxidant capacity (TAC). RESULTS: The NK cell activation markers, CD25 and CD69, were not affected by tBHQ consumption. Additionally, tBHQ did not have an effect on maturation of NK cells or interferon (IFN)γ production. Notably, NK cell expression of granzyme B was significantly decreased with tBHQ in infected mice. Furthermore, mice on the tBHQ diet showed decreased TAC after two days of infection compared to mice on the control diet, suggesting increased oxidative stress in the tBHQ group. CONCLUSIONS: tBHQ had no effect on NK cell activation, maturation, and IFNγ production after two days of influenza infection. However, decreased expression of granzyme B by NK cells suggests tBHQ may impair NK cell cytoxicity during the infection. Moreover, the decrease in TAC suggests increased oxidative stress in the tBHQ-treated mice. FUNDING SOURCES: This study was funded by National Institute of Environmental Health Sciences (ES024966).

Influenza virus infections have been a persistent threat to society, causing up to 650,000 respiratory deaths annually world-wide. The United States alone suffered 80,000 influenza-related deaths d...

Kupffer cells and monocyte-derived macrophages are critical for liver repair after acetaminophen (APAP) overdose. These cells produce promitogenic cytokines and growth factors, and they phagocytose dead cell debris, a process that is critical for resolution of inflammation. The factors that regulate these dynamic functions of macrophages after APAP overdose, however, are not fully understood. We tested the hypothesis that the fibrinolytic enzyme, plasmin, is a key regulator of macrophage function after APAP-induced liver injury. In these studies, inhibition of plasmin in mice with tranexamic acid delayed up-regulation of proinflammatory cytokines after APAP overdose. In culture, plasmin directly, and in synergy with high-mobility group B1, stimulated Kupffer cells and bone marrow–derived macrophages to produce cytokines by a mechanism that required NF-κB. Inhibition of plasmin in vivo also prevented trafficking of monocyte-derived macrophages into necrotic lesions after APAP overdose. This prevented phagocytic removal of dead cells, prevented maturation of monocyte-derived macrophages into F4/80-expressing macrophages, and prevented termination of proinflammatory cytokine production. Our studies reveal further that phagocytosis is an important stimulus for cessation of proinflammatory cytokine production as treatment of proinflammatory, monocyte-derived macrophages, isolated from APAP-treated mice, with necrotic hepatocytes decreased expression of proinflammatory cytokines. Collectively, these studies demonstrate that plasmin is an important regulator of macrophage function after APAP overdose.

Perivascular adipose tissue (PVAT) is protective and reduces contraction of blood vessels in health. PVAT is composed of adipocytes, multiple types of immune cells and stromal cells. Interleukin (IL)-10, an anti-inflammatory cytokine usually produced by T cells, B cells and macrophages, was identified as one of the highly expressed (mRNA) cytokines in the mesenteric PVAT of healthy rats. One report suggested that exogenous IL-10 causes relaxation of mouse mesenteric arteries, also suggesting that IL-10 maybe a potential anti-contractile factor. Hence, we hypothesized that PVAT-derived IL-10 causes vasorelaxation and/or reduces vasoconstriction, thus contributing to the anti-contractile nature of PVAT in health. Mesenteric arteries from rats and mice expressed the receptor for IL-10 (in tunica intima and media) as determined by immunohistochemistry. Mesenteric resistance arteries for rats and superior mesenteric artery for mice were used for isometric contractility studies. Increasing concentrations [0.4– 100 ng/mL] of recombinant rat/ mouse (rr/ mr) IL-10 or vehicle was directly added to half-maximally constricted (phenylephrine, PE) vessels (without PVAT, with endothelium). IL-10 did not cause a direct vasorelaxation. Further, the ability of rrIL-10 to cause a rightward or downward shift of a vasoconstriction-response curve was tested in the rat. The vessels were incubated with rrIL-10 [100 ng/mL or 10 ng/mL] or vehicle for 1.5 hours in the tissue bath followed by a cumulative PE [10(−8)–10(−4) M] or U46619 [10(−10)–10(−5) M] response curve. The maximal contractions and EC(50) values were similar in IL-10 incubated vessels vs vehicle. Thus, acute exposure of exogenous IL-10 did not reduce local vasoconstriction. To further test if endogenous IL-10 from PVAT was anti-contractile, superior mesenteric arteries from IL-10 WT and KO mice, with and without PVAT, were subjected to increasing concentrations of PE. The anti-contractile nature of PVAT was preserved with both short-term and prolonged depletion (using younger and older mice, respectively) of endogenous IL-10 in males and females. Contrary to our hypothesis, PVAT-derived IL-10 neither caused vasorelaxation nor reduced local vasoconstriction directly/ indirectly. Therefore, IL-10 does not contribute to the anti-contractile nature of PVAT in healthy rodents.

Perfluorononanoic acid (PFNA) is a perfluoroalkyl substance (PFAS) that is structurally related to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Whereas PFOA and PFOS are known immunotoxicants, PFNA is less well characterized. Our previous study showed that PFNA has immunomodulatory effects on leukocyte populations and immune function. The present studies sought to determine whether, and to what degree, the immune system recovered 28 days after PFNA exposure. None of the parameters measured had fully recovered. A few parameters had partially recovered, including decreased spleen size and the decreased ratio of the CD4+/CD8+ double-positive population in thymus. The majority of effects of PFNA remained unchanged 28 days after exposure, including decreased proportion of intact thymocytes (as determined by FSC vs SSC), alterations in the ratios of immune cell populations in spleen and the CD4+, CD8+ and double-negative populations in thymus. Notably, PFNA markedly increased the TNFα response to LPS in vivo, and no recovery was evident 28 days after exposure. The effect of PFNA on CD4+ T cells, CD8+ T cells and CD19+ cells was more pronounced in females. The current study demonstrates that a single high dose exposure to PFNA (e.g. as might occur accidentally in an occupational setting) has long-lasting effects on the immune system.

Melanoma is the most dangerous form of skin cancer with the majority of deaths arising from metastatic disease. Evidence implicates Rho-activated gene transcription in melanoma metastasis mediated by the nuclear localization of the transcriptional coactivator, myocardin-related transcription factor (MRTF). Here, we highlight a role for Rho and MRTF signaling and its reversal by pharmacologic inhibition using in vitro and in vivo models of human melanoma growth and metastasis. Using two cellular models of melanoma, we clearly show that one cell type, SK-Mel-147, is highly metastatic, has high RhoC expression, and MRTF nuclear localization and activity. Conversely, SK-Mel-19 melanoma cells have low RhoC expression, and decreased levels of MRTF-regulated genes. To probe the dependence of melanoma aggressiveness to MRTF transcription, we use a previously developed small-molecule inhibitor, CCG-203971, which at low micromolar concentrations blocks nuclear localization and activity of MRTF-A. In SK-Mel-147 cells, CCG-203971 inhibits cellular migration and invasion, and decreases MRTF target gene expression. In addition, CCG-203971–mediated inhibition of the Rho/MRTF pathway significantly reduces cell growth and clonogenicity and causes G1 cell-cycle arrest. In an experimental model of melanoma lung metastasis, the RhoC-overexpressing melanoma cells (SK-Mel-147) exhibited pronounced lung colonization compared with the low RhoC–expressing SK-Mel-19. Furthermore, pharmacologic inhibition of the MRTF pathway reduced both the number and size of lung metastasis resulting in a marked reduction of total lung tumor burden. These data link Rho and MRTF-mediated signaling with aggressive phenotypes and support targeting the MRTF transcriptional pathway as a novel approach to melanoma therapeutics. Mol Cancer Ther; 16(1); 193–204. ©2016 AACR.

Coagulation cascade activation and fibrin deposits have been implicated or observed in diverse forms of liver damage. Given that fibrin amplifies pathological inflammation in several diseases through the integrin receptor αMβ2, we tested the hypothesis that disruption of the fibrin(ogen)-αMβ2 interaction in Fibγ(390-396A) mice would reduce hepatic inflammation and fibrosis in an experimental setting of chemical liver injury. Contrary to our hypothesis, α-naphthylisothiocyanate (ANIT)-induced liver fibrosis increased in Fibγ(390-396A) mice, whereas inflammatory cytokine expression and hepatic necrosis were similar to ANIT-challenged wild-type (WT) mice. Increased fibrosis in Fibγ(390-396A) mice appeared to be independent of coagulation factor 13 (FXIII) transglutaminase, as ANIT challenge in FXIII-deficient mice resulted in a distinct pathological phenotype characterized by increased hepatic necrosis. Rather, bile duct proliferation underpinned the increased fibrosis in ANIT-exposed Fibγ(390-396A) mice. The mechanism of fibrin-mediated fibrosis was linked to interferon (IFN)γ induction of inducible nitric oxide synthase (iNOS), a gene linked to bile duct hyperplasia and liver fibrosis. Expression of iNOS messenger RNA was significantly increased in livers of ANIT-exposed Fibγ(390-396A) mice. Fibrin(ogen)-αMβ2 interaction inhibited iNOS induction in macrophages stimulated with IFNγ in vitro and ANIT-challenged IFNγ-deficient mice had reduced iNOS induction, bile duct hyperplasia, and liver fibrosis. Further, ANIT-induced iNOS expression, liver fibrosis, and bile duct hyperplasia were significantly reduced in WT mice administered leukadherin-1, a small molecule that allosterically enhances αMβ2-dependent cell adhesion to fibrin. These studies characterize a novel mechanism whereby the fibrin(ogen)-integrin-αMβ2 interaction reduces biliary fibrosis and suggests a novel putative therapeutic target for this difficult-to-treat fibrotic disease.

Nrf2 is a transcription factor that regulates cytoprotective cellular responses to oxidative and electrophilic stress. Nrf2 is potently activated by the synthetic food additive, tert-butylhydroquinone (tBHQ), which is widely used as a preservative in oils and processed foods. Previously published studies have established that tBHQ has numerous effects on T cell function. The purpose of this study was to determine the effect of tBHQ on B cell function and the role of Nrf2 in these effects. Specifically, we investigated T cell-independent B cell activation, differentiation, and IgM antibody production. Murine wild-type and Nrf2-null splenocytes were isolated, treated with tBHQ (0.25–2.5 μm), and activated by lipopolysaccharide (LPS), a T cell-independent B cell activator. Our findings indicate that tBHQ significantly enhanced IgM production in activated wild-type, but not Nrf2-null, B cells, suggesting this effect is Nrf2-dependent. In contrast, tBHQ significantly decreased the induction of CD69, CD25, CD22, and CD138 in both wild-type and Nrf2-null splenocytes. These findings indicate that the tBHQ-mediated increase in IgM is Nrf2-dependent, whereas the inhibition of CD69, CD25, CD22 and CD138 is Nrf2-independent. Overall, this study demonstrates that in addition to its effects on T cells, tBHQ also has potent effects on T cell-independent B cell function.

Perivascular adipose tissue (PVAT) may be a key player in mediating adiposity-associated hypertension because of its proximity to blood vessels. Although increased immune cell occupancy in adipose tissue is proposed to couple adiposity to hypertension, little is known about PVAT’s immune complement. We hypothesized that an immune complement exists in PVAT that would become pro-inflammatory with adiposity-induced hypertension. Male and female Dahl S rats were fed a regular (10% calories from fat) diet (control) or a high fat (60%) diet (HFD) from weaning through 24 weeks of age. HFD rats demonstrated significantly higher systolic blood pressure [mm Hg; control: 127±7 (M), 145±8 (F); HFD: 168±9 (M), 184±11 (F); tail cuff] and visceral adiposity (micro-CT scans). PVATs from the thoracic aorta (APVAT), mesenteric resistance vessels (MRPVAT), non-PVAT retroperitoneal fat (RP fat) and spleen (positive control) were harvested from each animal. T cells (CD4 and CD8), B cells, macrophages, mast cells and neutrophils in the stromal vascular fraction were quantified using 7-color flow cytometry. The type and number of immune cells are presented as a percentage (%) of total live singlet cells. Each immune cell type is reported as % of total immune cells, and CD4, CD8 cells as % of T cells. The table illustrates significant (Pvs respective controls. HFD-induced hypertension in Dahl S rats leads to greater macrophage infiltration of MRPVAT and RP fat in females vs males. Further studies are needed to gain mechanistic insights into how macrophage subtypes and their associated cytokines in PVAT may alter vascular tone and blood pressure.

The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) regulates a battery of antioxidant, detoxification, and cell stress genes. It is activated by oxidative stress and a number of exogenous compounds, one of which is tert-butylhydroquinone (tBHQ), a widely used food preservative. Nrf2 modulates immune responses in numerous rodent models of inflammation, but its effects on human immune cells are not well characterized. The purpose of these studies was to evaluate the effects of the Nrf2 activator tBHQ on early events of T cell activation in primary human cells. Treatment with tBHQ induced mRNA expression of the Nrf2 target genes HMOX-1, GCLC, and NQO1, and also increased NRF2 mRNA expression, albeit to a lesser extent than the other target genes. tBHQ decreased production of the cytokines IL-2 and IFN-γ at both the protein and mRNA levels after stimulation with anti-CD3/anti-CD28 in human peripheral blood mononuclear cells and to an even greater extent in isolated CD4 T cells. Likewise, tBHQ decreased induction of CD25 and CD69 in peripheral blood mononuclear cells (PBMCs) and this decrease was even more marked in isolated CD4 T cells. In addition, tBHQ inhibited induction of NFκB DNA binding in anti-CD3/anti-CD28-activated PBMCs. Collectively, these data suggest that tBHQ inhibits activation of primary human CD4 T cells, which correlates with activation of Nrf2 and inhibition of NFκB DNA binding. Although these studies suggest the food additive tBHQ negatively impacts T cell activation, further studies will be needed to fully elucidate the effect of tBHQ on human immune responses.

Bile acids (BAs) are known to regulate BA synthesis and transport by the farnesoid X receptor in the liver (FXR-SHP) and intestine (FXR-Fgf15). However, the relative importance of individual BAs in regulating these processes is not known. Therefore, mice were fed various doses of five individual BAs, including cholic acid (CA), chenodeoxycholic acid (CDCA), deoxoycholic acid (DCA), lithocholic acid (LCA), and ursodeoxycholic acid (UDCA) in their diets at various concentrations for one week to increase the concentration of one BA in the enterohepatic circulation. The mRNA of BA synthesis and transporting genes in liver and ileum were quantified. In the liver, the mRNA of SHP, which is the prototypical target gene of FXR, increased in mice fed all concentrations of BAs. In the ileum, the mRNA of the intestinal FXR target gene Fgf15 was increased at lower doses and to a higher extent by CA and DCA than by CDCA and LCA. Cyp7a1, the rate-limiting enzyme in BA synthesis, was decreased more by CA and DCA than CDCA and LCA. Cyp8b1, the enzyme that 12-hydroxylates BAs and is thus responsible for the synthesis of CA, was decreased much more by CA and DCA than CDCA and LCA. Surprisingly, neither a decrease in the conjugated BA uptake transporter (Ntcp) nor increase in BA efflux transporter (Bsep) was observed by FXR activation, but an increase in the cholesterol efflux transporter (Abcg5/Abcg8) was observed with FXR activation. Thus in conclusion, CA and DCA are more potent FXR activators than CDCA and LCA when fed to mice, and thus they are more effective in decreasing the expression of the rate limiting gene in BA synthesis Cyp7a1 and the 12-hydroxylation of BAs Cyp8b1, and are also more effective in increasing the expression of Abcg5/Abcg8, which is responsible for biliary cholesterol excretion. However, feeding BAs do not alter the mRNA or protein levels of Ntcp or Bsep, suggesting that the uptake or efflux of BAs is not regulated by FXR at physiological and pharmacological concentrations of BAs.

We previously demonstrated that activation of the transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2) promotes CD4+ Th2 differentiation. In the current study, we assessed the role of Nrf2 in early events following T cell activation. The Nrf2 activators, tBHQ (tert-butylhydroquinone) and CDDO-Im (the imidazolide derivative of the triterpenoid CDDO), were used in conjunction with splenocytes derived from wild-type and Nrf2-null mice to distinguish between Nrf2-specific and off-target effects. CDDO-Im inhibited early IFNγ and TNFα production in a largely Nrf2-dependent manner. In contrast, tBHQ and CDDO-Im had little effect on expression of CD25 or CD69. Furthermore, tBHQ inhibited GM-CSF and IL-2 production in both wild-type and Nrf2-null T cells, suggesting this effect is Nrf2-independent. Conversely, CDDO-Im caused a concentration-dependent increase in IL-2 secretion in wild-type, but not Nrf2-null, splenocytes, suggesting that Nrf2 promotes IL-2 production. Interestingly, both compounds inhibit NFκB DNA binding, where the suppression by tBHQ is Nrf2-independent and CDDO-Im is Nrf2-dependent. Surprisingly, as compared to wild-type splenocytes, Nrf2-null splenocytes showed lower nuclear accumulation of c-Jun, a member of the AP-1 family of transcription factors, which have been shown to drive multiple immune genes, including IL-2. Both Nrf2 activators caused a Nrf2-dependent trend towards increased nuclear accumulation of c-Jun. These data suggest that modulation of cytokine secretion by tBHQ likely involves multiple pathways, including AP-1, NFκB, and Nrf2. Overall, the data suggest that Nrf2 activation inhibits secretion of the Th1 cytokine IFNγ, and increases early production of IL-2, which has been shown to promote Th2 differentiation, and may support the later occurrence of Th2 polarization.

SummaryBackground The prevalence of asthma in the elderly is increasing and associated with higher mortality than in children or young adults. However, the effects of age on the development and character of allergic asthma have been understudied. It has been suggested that mixed Th2/Th17 responses cause more severe forms of asthma, but the role of Th17 response in allergic airway disease and aging is not well understood. Objective To investigate age-dependent characteristics and Th17 immune response in allergic airway disease in a murine house dust mite (HDM)-allergen model. Methods Twelve-week-old and 15-month-old male BALB/c mice were sensitized and challenged with HDM. Bronchoalveolar lavage fluid (BALF), airway inflammation and hyperresponsiveness (AHR), serum immunoglobulin and splenic T cells were assessed. Age-related T cell activation was analyzed in a co-culture with bone marrow-derived dendritic cells (BMDC) and splenic CD4+T cells from young and old mice. Results Features of allergic airway disease such as mucous cell hyperplasia, infiltration of airway eosinophils and lymphocytes, Th2 cytokine expression and serum IgG1 levels were greater in old compared to young mice. In contrast to the more marked inflammatory/immune responses to HDM in old mice, AHR was greater in young HDM-treated mice. Only the old mice developed airway neutrophil infiltration and a Th17 immune response upon HDM exposure, with increases in BALF cytokines IL-17A and KC, and Th17 cytokine producing T cells in the spleen. Stimulation of CD4+T cells and BMDC co-cultures with HDM, resulted in an enhanced Th17 cytokine response in cells isolated from old mice. Conclusions and Clinical Relevance Our findings in mice suggest that the severity and character of allergic airway disease are age dependent, with a bias towards a Th17 immune response with aging. Elderly, asthmatics may be prone to develop severe allergic airway inflammation with a mixed Th2/Th17 immune response.

Hypoxia-inducible factor-1α (HIF-1α) is activated in hepatic stellate cells (HSCs) by hypoxia and regulates genes important for tissue repair. Whether HIF-1α is activated in HSCs after acute injury and contributes to liver regeneration, however, is not known. To investigate this, mice were generated with reduced levels of HIF-1α in HSCs by crossing HIF-1α floxed mice with mice that express Cre recombinase under control of the glial fibrillary acidic protein (GFAP) promoter (i.e., HIF-1α-GFAP Cre+ mice). These mice and control mice (i.e., HIF-1α-GFAP Cre− mice) were treated with a single dose of carbon tetrachloride, and liver injury and repair were assessed. After carbon tetrachloride, HIF-1α was activated in HSCs. Although liver injury was not different between the two strains of mice, during resolution of injury, clearance of necrotic cells was decreased in HIF-1α-GFAP Cre+ mice. In these mice, the persistence of necrotic cells stimulated a fibrotic response characterized by extensive collagen deposition. Hepatic accumulation of macrophages, which clear necrotic cells from the liver after carbon tetrachloride, was not affected by HIF-1α deletion in HSCs. Conversion of macrophages to M1-like, proinflammatory macrophages, which have increased phagocytic activity, however, was reduced in HIF-1α-GFAP Cre+ mice as indicated by a decrease in proinflammatory cytokines and a decrease in the percentage of Gr1hi macrophages. Collectively, these studies have identified a novel function for HSCs and HIF-1α in orchestrating the clearance of necrotic cells from the liver and demonstrated a key role for HSCs in modulating macrophage phenotype during acute liver injury.

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a stress-activated transcription factor activated by stimuli such as electrophilic compounds and other reactive xenobiotics. Previously, we have shown that the commonly used food additive and Nrf2 activator tert-butylhydroquinone (tBHQ) suppresses interleukin-2 (IL-2) production, CD25 expression, and NFκB activity in human Jurkat T cells. The purpose of the current studies was to determine whether these effects were dependent upon Nrf2 by developing a human Nrf2-null T cell model using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 technology. The current studies show that suppression of CD25 expression by tBHQ is partially dependent on Nrf2, whereas inhibition of IL-2 secretion is largely Nrf2-independent. Interestingly, tBHQ inhibited NFκB activation in an Nrf2-independent manner. This was an unexpected finding since Nrf2 inhibits NFκB activation in other models. These results led us to investigate another more potent Nrf2 activator, the synthetic triterpenoid 1[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im). Treatment of wild-type and Nrf2-null Jurkat T cells with CDDO-Im resulted in an Nrf2-dependent suppression of IL-2. Furthermore, susceptibility to reactive oxygen species was significantly enhanced in the Nrf2-null clones as determined by decreased mitochondrial membrane potential and cell viability. Importantly, this study is the first to describe the generation of a human Nrf2-null model, which is likely to have multiple applications in immunology and cancer biology. Collectively, this study demonstrates a role for Nrf2 in the effects of CDDO-Im on CD25 and IL-2 expression, whereas the effect of tBHQ on these parameters is complex and likely involves modulation of multiple stress-activated transcription factors, including NFκB and Nrf2.

Background: The development of common forms of hypertension (HTN) involves both genetic and environmental factors. Methylation changes (one of the epigenetic modifications) of DNA may play a role in the regulation of BP and development of HTN, and may result from interaction of specific genes with the environment. The current study investigates the relationship between genome-wide changes in DNA methylation in T-lymphocytes and BP level differences among monozygotic twins, who have identical DNA sequences. Methods: In a preliminary study, we recruited 24 pairs of monozygotic twins (60% women) with a mean age of 44 ± 10 years. Zygosity was determined via self-report or participants’ responses to a standard zygosity questionnaire. BPs were measured in triplicate after 5 minutes of rest at one minute intervals and averaged. Anthropometrics measurements were obtained along with blood for isolation of T-lymphocytes. DNA from T-lymphocytes was used to perform reduced representation bisulfite sequencing (RRBS) to measure methylation levels at single-base resolution in these subjects. Average differences in systolic (SBP) and diastolic (DBP) BPs were used as continuous variables for these analyses. Results: Mean SBP was 124 ± 15 (range (r): 97-174) mm Hg and mean DBP was 78 ± 11 (r: 49-106) mm Hg. Average differences in SBP and DBP among the co-twins (members of a twin pair) were 9 ± 10 (r: 0-40) mm Hg and 8 ± 6 (r: 0-26) mm Hg respectively. Average BMI was 29 ± 8 kg/m 2 . We observed that an average of 3063 (r: 757-7250) CpG islands were differentially methylated (DMRs) between co-twins. Among these DMRs, 10 were associated with average SBP difference and 5 were associated with average DBP difference at a significance level of p < 0.001. DMRs showing the strongest association (unadjusted p < 10 -4 ) between the co-twins were located in the transcriptional start site (TSS) of genes: CDC26 (cell division cycle protein) and NR2F6 (nuclear receptor) for average SBP difference and LEPRE1 (propyl 3 hydroxylase protein) for average DBP difference. Conclusions: BP differences between monozygotic co-twins, which most likely result from environmental factors, appear to be associated with differences in DNA methylation in T lymphocytes.

NF erythroid 2-related factor 2 (Nrf2) is a transcription factor that mediates the upregulation of a battery of cytoprotective genes in response to cell stress. Recent studies showed that Nrf2 also modulates immune responses and exhibits anti-inflammatory activity. In this article, we demonstrate that a common food preservative, tert-butylhydroquinone, can activate Nrf2 in T cells, as evidenced by Nrf2 binding to the antioxidant response element and the subsequent upregulation of Nrf2 target genes. The activation of Nrf2 suppresses IFN-γ production, while inducing the production of the Th2 cytokines IL-4, IL-5, and IL-13. Nrf2 activation also suppresses T-bet DNA binding and promotes GATA-binding protein 3 DNA binding. Collectively, the present studies suggested that Nrf2 activation skews CD4+ T cells toward Th2 differentiation and, thus, represents a novel regulatory mechanism in CD4+ T cells. Further studies are needed to determine whether the commercial use of Nrf2 activators as food preservatives promotes food allergies in humans.

Background and Purpose: The proteasome is a multi-subunit complex that proteolytically cleaves proteins. The replacement of the constitutive proteasome subunits β1, β2, and/or β5 with the IFNγ-inducible subunits LMP2, MECL1, and/or LMP7 results in the ‘immunoproteasome’. The inducible subunits change the cleavage specificities of the proteasome, but it is unclear whether they have functions in addition to this. The purpose of the present study was to determine the role of the proteasome in general, as well as LMP7 and MECL1 specifically, with regard to cytokine production by activated primary splenocytes. Methods: A LMP7/MECL1-null mouse was engineered to determine the roles of these subunits in cytokine production. Isolated splenocytes from wild-type and LMP7/MECL1–/– mice were treated with lactacystin and activated with PMA and ionomycin and subsequently cytokine mRNA levels were quantified. Results: The present study demonstrates that LMP7/MECL1 regulates the expression of IFNγ, IL4, IL10, IL2Rβ, GATA3, and t-bet. In contrast, the regulation of IL2, IL13, TNFα, and IL2Rα by the proteasome appears to occur independently of LMP7/MECL1. Conclusions: Collectively, the present study demonstrates that LMP7 and MECL1 regulate cytokine expression, suggesting this system represents a novel mechanism for the regulation of cytokines and cytokine signaling.

The pregnane X receptor (PXR) is a key regulator of xenobiotic metabolism and disposition in liver. However, little is known about the PXR DNA-binding signatures in vivo, or how PXR regulates novel direct targets on a genome-wide scale. Therefore, we generated a roadmap of hepatic PXR bindings in the entire mouse genome [chromatin immunoprecipitation (ChIP)-Seq]. The most frequent PXR DNA-binding motif is the AGTTCA-like direct repeat with a 4 bp spacer [direct repeat (DR)-4)]. Surprisingly, there are also high motif occurrences with spacers of a periodicity of 5 bp, forming a novel DR-(5 n+4) pattern for PXR binding. PXR-binding overlaps with the epigenetic mark for gene activation (histone-H3K4-di-methylation), but not with epigenetic marks for gene suppression (DNA methylation or histone-H3K27-tri-methylation) (ChIP-on-chip). After administering a PXR agonist, changes in mRNA of most PXR-direct target genes correlate with increased PXR binding. Specifically, increased PXR binding triggers the trans-activation of critical drug-metabolizing enzymes and transporters. The mRNA induction of these genes is absent in PXR-null mice. The current work provides the first in vivo evidence of PXR DNA-binding signatures in the mouse genome, paving the path for predicting and further understanding the multifaceted roles of PXR in liver.

Activation of Nrf2 and its downstream target genes serves as a master defense mechanism, protecting cells against oxidative and electrophilic stress. Numerous activators of Nrf2 inhibit carcinogenesis. However, genetic alterations resulting in constitutive Nrf2 activation in human lung tumors promotes tumor growth and chemoresistance. The dual role of Nrf2 in cancer has generated a high level of interest, but little is known regarding the effect of Nrf2 on immune cells during lung carcinogenesis. In this study, we used the potent carcinogen vinyl carbamate to induce lung tumors in mice. Tumor burden, the immunophenotype, and genetic signatures were compared in the lungs of Nrf2 knockout (-/-, KO) vs. wildtype (+/+, WT) mice. Nrf2 KO mice were more susceptible to vinyl carbamate; these mice developed tumors earlier than the WT mice and exhibited more and larger tumors over times ranging from 20-32 weeks after initiation. By 32 weeks, WT mice have an average of 6.5 ± 0.95 tumors per lung compared to 12.25 ± 2.6 tumors in the KO mice. Immune cell populations including T cells (CD4+ and CD8+), B cells, macrophages and myeloid derived suppressor cells were investigated in the lungs and spleens of Nrf2 WT and KO mice challenged with vinyl carbamate. T cell populations were significantly (P < 0.05) reduced in the lungs of Nrf2 KO mice, while tumor-promoting macrophages and myeloid derived suppressor cells were elevated in the lung and spleen, respectively, of Nrf2 KO mice compared to WT mice. Moreover, immune response genes, especially a series of cytokines (Cxcl1, Cxcl12, Csf1, and Ccl9) and MHC antigens that promote tumor growth, were significantly upregulated in tumors from Nrf2-/- mice. Importantly, this expression profile is conserved in patients with lung cancer. Overall, our results confirmed a tumor protective role of Nrf2 in carcinogenesis and suggest an important regulatory role for Nrf2 in immune cells in both mouse and human lung tumors. Citation Format: Di Zhang, Jonathan Rennhack, Eran Andrechek, Cheryl Rockwell, Karen Liby. Different immune signatures in advanced lung tumors of Nrf2 wildtype vs. knockout mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4051.