Search

In lung, thromboxane [A.sub.2] ([TXA.sub.2]) activates the TP receptor to induce proinflammatory and bronchoconstrictor effects. Thus, TP receptor antagonists and [TXA.sub.2] synthase inhibitors have been tested as potential asthma therapeutics in humans. Th9 cells play key roles in asthma and regulate the lung immune response to allergens. Herein, we found that [TXA.sub.2] reduces Th9 cell differentiation during allergic lung inflammation. Th9 cells were decreased approximately 2-fold and airway hyperresponsiveness was attenuated in lungs of allergic mice treated with [TXA.sub.2]. Naive [CD4.sup.+] T cell differentiation to Th9 cells and IL-9 production were inhibited dose-dependently by [TXA.sub.2] in vitro. TP receptor-deficient mice had an approximately 2-fold increase in numbers of Th9 cells in lungs in vivo after OVA exposure compared with wild-type mice. Naive [CD4.sup.+] T cells from TP- deficient mice exhibited increased Th9 cell differentiation and IL-9 production in vitro compared with [CD4.sup.+] T cells from wild-type mice. [TXA.sub.2] also suppressed Th2 and enhanced Treg differentiation both in vitro and in vivo. Thus, in contrast to its acute, proinflammatory effects, [TXA.sub.2] also has longer-lasting immunosuppressive effects that attenuate the Th9 differentiation that drives asthma progression. These findings may explain the paradoxical failure of anti-thromboxane therapies in the treatment of asthma., Introduction Development of allergic lung inflammation is a complex process involving both immune and inflammatory events. In the immune phase, allergens are taken up and processed by antigen-presenting cells such [...]

BackgroundDiabetic nephropathy (DN) is the leading cause of renal failure, and podocyte dysfunction contributes to the pathogenesis of DN. Soluble epoxide hydrolase (sEH, encoded by Ephx2) is a conserved cytosolic enzyme whose inhibition has beneficial effects on renal function. The aim of this study is to investigate the contribution of sEH in podocytes to hyperglycemia-induced renal injury.Materials and methodsMice with podocyte-specific sEH disruption (pod-sEHKO) were generated, and alterations in kidney function were determined under normoglycemia, and high-fat diet (HFD)- and streptozotocin (STZ)-induced hyperglycemia.ResultssEH protein expression increased in murine kidneys under HFD- and STZ-induced hyperglycemia. sEH deficiency in podocytes preserved renal function and glucose control and mitigated hyperglycemia-induced renal injury. Also, podocyte sEH deficiency was associated with attenuated hyperglycemia-induced renal endoplasmic reticulum (ER) stress, inflammation and fibrosis, and enhanced autophagy. Moreover, these effects were recapitulated in immortalized murine podocytes treated with a selective sEH pharmacological inhibitor. Furthermore, pharmacological-induced elevation of ER stress or attenuation of autophagy in immortalized podocytes mitigated the protective effects of sEH inhibition.ConclusionsThese findings establish sEH in podocytes as a significant contributor to renal function under hyperglycemia.General significanceThese data suggest that sEH is a potential therapeutic target for podocytopathies.

Podocytes play an important role in maintaining glomerular function, and podocyte injury is a significant component in the pathogenesis of proteinuria. Soluble epoxide hydrolase (sEH) is a cytosolic enzyme whose genetic deficiency and pharmacological inhibition have beneficial effects on renal function, but its role in podocytes remains unexplored. The objective of this study was to investigate the contribution of sEH in podocytes to lipopolysaccharide (LPS)-induced kidney injury. We report increased sEH transcript and protein expression in murine podocytes upon LPS challenge. To determine the function of sEH in podocytes in vivo we generated podocyte-specific sEH-deficient (pod-sEHKO) mice. Following LPS challenge, podocyte sEH-deficient mice exhibited lower kidney injury, proteinuria, and blood urea nitrogen concentrations than controls suggestive of preserved renal function. Also, renal mRNA and serum concentrations of inflammatory cytokines IL-6, IL-1β, and TNFα were significantly lower in LPS-treated pod-sEHKO than control mice. Moreover, podocyte sEH deficiency was associated with decreased LPS-induced NF-κB and MAPK activation and attenuated endoplasmic reticulum stress. Furthermore, the protective effects of podocyte sEH deficiency in vivo were recapitulated in E11 murine podocytes treated with a selective sEH pharmacological inhibitor. Altogether, these findings identify sEH in podocytes as a contributor to signaling events in acute renal injury and suggest that sEH inhibition may be of therapeutic value in proteinuria.EnzymesSoluble epoxide hydrolase: EC 3.3.2.10.

Epoxyeicosatrienoic acids (EETs) have potent antiinflammatory properties. Hydrolysis of EETs by soluble epoxide hydrolase/ epoxide hydrolase 2 (sEH/EPHX2) to less active diols attenuates their antiinflammatory effects. Macrophage activation is critical to many inflammatory responses; however, the role of EETs and sEH in regulating macrophage function remains unknown. Lung bacterial clearance of Streptococcus pneumoniae was impaired in Ephx2-deficient ([Ephx2.sup.-/-]) mice and in mice treated with an sEH inhibitor. The EET receptor antagonist EEZE restored lung clearance of S. pneumoniae in Ephx2 /mice. [Ephx2.sup.-/-] mice had normal lung Il1b, Il6, and Tnfa expression levels and macrophage recruitment to the lungs during S. pneumoniae infection; however, Ephx2 disruption attenuated proinflammatory cytokine induction, Tlr2 and Pgylrp1 receptor upregulation, and Ras-related C3 botulinum toxin substrates 1 and 2 (Rac1/2) and cell division control protein 42 homolog (Cdc42) activation in PGN-stimulated macrophages. Consistent with these observations, [Ephx2.sup.-/-] macrophages displayed reduced phagocytosis of S. pneumoniae in vivo and in vitro. Heterologous overexpression of TLR2 and peptidoglycan recognition protein 1 (PGLYRP1) in [Ephx2.sup.-/-] macrophages restored macrophage activation and phagocytosis. Human macrophage function was similarly regulated by EETs. Together, these results demonstrate that EETs reduced macrophage activation and phagocytosis of S. pneumoniae through the downregulation of TLR2 and PGLYRP1 expression. Defining the role of EETs and sEH in macrophage function may lead to the development of new therapeutic approaches for bacterial diseases., Introduction Pneumonia is the leading cause of mortality in the United States Streptococcus pneumoniae and Klebsiella pneumoniae are the mosi frequently isolated bacterial pathogens in community-acquirec pneumonia (1). Together, these [...]

Nongenomic effects of estrogen receptor α (ERα) signaling have been described for decades. Several distinct animal models have been generated previously to analyze the nongenomic ERα signaling (eg, membrane-only ER, and ERαC451A). However, the mechanisms and physiological processes resulting solely from nongenomic signaling are still poorly understood. Herein, we describe a novel mouse model for analyzing nongenomic ERα actions named H2NES knock-in (KI). H2NES ERα possesses a nuclear export signal (NES) in the hinge region of ERα protein resulting in exclusive cytoplasmic localization that involves only the nongenomic action but not nuclear genomic actions. We generated H2NESKI mice by homologous recombination method and have characterized the phenotypes. H2NESKI homozygote mice possess almost identical phenotypes with ERα null mice except for the vascular activity on reendothelialization. We conclude that ERα-mediated nongenomic estrogenic signaling alone is insufficient to control most estrogen-mediated endocrine physiological responses; however, there could be some physiological responses that are nongenomic action dominant. H2NESKI mice have been deposited in the repository at Jax (stock no. 032176). These mice should be useful for analyzing nongenomic estrogenic responses and could expand analysis along with other ERα mutant mice lacking membrane-bound ERα. We expect the H2NESKI mouse model to aid our understanding of ERα-mediated nongenomic physiological responses and serve as an in vivo model for evaluating the nongenomic action of various estrogenic agents. [ABSTRACT FROM AUTHOR]

Control of the inflammatory response is critical to maintaining homeostasis, and failure to do so contributes to the burden of chronic inflammation associated with several disease states. The mechanisms that underlie immunosuppression, however, remain largely unknown. Although defects in autophagy machinery have been associated with inflammatory pathologic conditions, we now appreciate that autophagic components participate in noncanonical pathways distinct from classical autophagy. We have previously demonstrated that LC3-associated phagocytosis (LAP), a noncanonical autophagic process dependent on Rubicon (rubicon autophagy regulator [RUBCN]), contributes to immunosuppression. We used Rubcn -/- mice to examine the role of the LAP pathway in mediating the UV-induced immunotolerant program in a model of contact hypersensitivity (CHS). Flow cytometry and transcriptional analysis were used to measure immune cell infiltration and activation in the skin of Rubcn +/+ and Rubcn -/- mice during the CHS response. Here, we demonstrate that LAP is required for UV-induced immunosuppression and that UV exposure induces a broadly anti-inflammatory transcriptional program dependent on Rubicon. Rubcn -/- mice are resistant to UV-induced immunosuppression and instead display exaggerated inflammation in a model of CHS. Specifically, RUBCN deficiency in CD301b+ dermal dendritic cells results in their increased antigen presentation capacity and subsequent hyperactivation of the CD8+ T-cell response. LAP functions to limit the immune response and is critical in maintaining the balance between homeostasis and inflammation. [ABSTRACT FROM AUTHOR]