Cytochrome P450 (CYP)-dependent arachidonic acid (AA) metabolites are involved in the regulation of renal vascular tone and salt excretion. The epoxygenation product 11,12-epoxyeicosatrienoic acid (EET) is anti-inflammatory and inhibits nuclear factor-kappa B activation. We tested the hypothesis that the peroxisome proliferator-activated receptor-alpha-activator fenofibrate (Feno) induces CYP isoforms, AA hydroxylation, and epoxygenation activity, and protects against inflammatory organ damage. Double-transgenic rats (dTGRs) overexpressing human renin and angiotensinogen genes were treated with Feno. Feno normalized blood pressure, albuminuria, reduced nuclear factor-kappa B activity, and renal leukocyte infiltration. Renal epoxygenase activity was lower in dTGRs compared to nontransgenic rats. Feno strongly induced renal CYP2C23 protein and AA-epoxygenase activity under pathological and nonpathological conditions. In both cases, CYP2C23 was the major isoform responsible for 11,12-EET formation. Moreover, we describe a novel CYP2C23-dependent pathway leading to hydroxy-EETs (HEETs), which may serve as endogenous peroxisome proliferator-activated receptor-alpha activators. The capacity to produce HEETs via CYP2C23-dependent epoxygenation of 20-HETE and CYP4A-dependent hydroxylation of EETs was reduced in dTGR kidneys and induced by Feno. These results demonstrate that Feno protects against angiotensin II-induced renal damage and acts as inducer of CYP2C23-mediated epoxygenase activities. We propose that CYP-dependent EET/HEET production may serve as an anti-inflammatory control mechanism.

Transcription factor AP-1 is constitutively activated and IRF4 drives growth and survival in ALK+ and ALK– anaplastic large cell lymphoma (ALCL). Here we demonstrate high-level BATF and BATF3 expression in ALCL. Both BATFs bind classical AP-1 motifs and interact with in ALCL deregulated AP-1 factors. Together with IRF4, they co-occupy AP-1-IRF composite elements, differentiating ALCL from non-ALCL. Gene-specific inactivation of BATFs, or global AP-1 inhibition results in ALCL growth retardation and/or cell death in vitro and in vivo. Furthermore, the AP-1-BATF module establishes TH17/group 3 innate lymphoid cells (ILC3)-associated gene expression in ALCL cells, including marker genes such as AHR, IL17F, IL22, IL26, IL23R and RORγt. Elevated IL-17A and IL-17F levels were detected in a subset of children and adolescents with ALK+ ALCL. Furthermore, a comprehensive analysis of primary lymphoma data confirms TH17–, and in particular ILC3-skewing in ALCL compared with PTCL. Finally, pharmacological inhibition of RORC as single treatment leads to cell death in ALCL cell lines and, in combination with the ALK inhibitor crizotinib, enforces death induction in ALK+ ALCL. Our data highlight the crucial role of AP-1/BATFs in ALCL and lead to the concept that some ALCL might originate from ILC3.

Key Points• IkB-z is essential for nuclear NF-kB activity in ABC DLBCL.• ABC DLBCL survival depends on IkB-z signaling.Constitutive activation of the nuclear factor-k B (NF-kB) pathway is a hallmark of the activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL). Recurrent mutations of NF-kB regulators that cause constitutive activity of this oncogenic pathway have been identified. However, it remains unclear how specific target genes are regulated. We identified the atypical nuclear IkB protein IkB-z to be upregulated in ABC compared with germinal center B-cell-like (GCB) DLBCL primary patient samples. Knockdown of IkB-z by RNA interference was toxic to ABC but not to GCB DLBCL cell lines. Gene expression profiling after IkB-z knockdown demonstrated a significant downregulation of a large number of known NF-kB target genes, indicating an essential role of IkB-z in regulating a specific set of NF-kB target genes. To further investigate how IkB-z mediates NF-kB activity, we performed immunoprecipitations and detected a physical interaction of IkB-z with both p50 and p52 NFkB subunits, indicating that IkB-z interacts with components of both the canonical and the noncanonical NF-kB pathway in ABC DLBCL. Collectively, our data demonstrate that IkB-z is essential for nuclear NF-kB activity in ABC DLBCL, and thus might represent a promising molecular target for future therapies. (Blood. 2013;122(13):2242-2250

BackgroundNF-κB is widely involved in lymphoid malignancies; however, the functional roles and specific transcriptomes of NF-κB dimers with distinct subunit compositions have been unclear.MethodsUsing combined ChIP-sequencing and microarray analyses, we determined the cistromes and target gene signatures of canonical and non-canonical NF-κB species in Hodgkin lymphoma (HL) cells.ResultsWe found that the various NF-κB subunits are recruited to regions with redundant κB motifs in a large number of genes. Yet canonical and non-canonical NF-κB dimers up- and downregulate gene sets that are both distinct and overlapping, and are associated with diverse biological functions. p50 and p52 are formed through NIK-dependent p105 and p100 precursor processing in HL cells and are the predominant DNA binding subunits. Logistic regression analyses of combinations of the p50, p52, RelA, and RelB subunits in binding regions that have been assigned to genes they regulate reveal a cross-contribution of p52 and p50 to canonical and non-canonical transcriptomes. These analyses also indicate that the subunit occupancy pattern of NF-κB binding regions and their distance from the genes they regulate are determinants of gene activation versus repression. The pathway-specific signatures of activated and repressed genes distinguish HL from other NF-κB-associated lymphoid malignancies and inversely correlate with gene expression patterns in normal germinal center B cells, which are presumed to be the precursors of HL cells.ConclusionsWe provide insights that are relevant for lymphomas with constitutive NF-κB activation and generally for the decoding of the mechanisms of differential gene regulation through canonical and non-canonical NF-κB signaling.Electronic supplementary materialThe online version of this article (doi:10.1186/s13073-016-0280-5) contains supplementary material, which is available to authorized users.

Abstract-Transgenic rats overexpressing both human renin and angiotensinogen genes (dTGR) develop hypertension, inflammation, and renal failure. We tested the hypothesis that these pathological features are associated with changes in renal P450-dependent arachidonic acid (AA) metabolism. Samples were prepared from 5-and 7-week-old dTGR and from normotensive Sprague-Dawley (SD) rats, ie, before and after the dTGR developed severe hypertension and albuminuria. At both stages, dTGR showed significantly lower renal microsomal AA epoxygenase and hydroxylase activities that reached 63% and 76% of the control values at week 7. Furthermore, the protein levels of several potential AA epoxygenases (CYP2C11, CYP2C23, and CYP2J) were significantly reduced. Immunoinhibition studies identified CYP2C23 as the major AA epoxygenase, both in dTGR and SD rats. Immunohistochemistry showed that CYP2C23 was localized in cortical and outer medullary tubules that progressively lost this enzyme from week 5 to week 7 in dTGR. CYP2C11 expression occurred only in the outer medullary tubules and was markedly reduced in dTGR compared with age-matched SD rats. These findings indicate site-specific decreases in the availability of AA epoxygenase products in the kidney of dTGR. In contrast to renal microsomes, liver microsomes of dTGR and SD rats showed no change in the expression and activity of AA epoxygenases and hydroxylases. We conclude that hypertension and end-organ damage in dTGR is associated with kidney-specific downregulation of P450-dependent AA metabolism. Because the products of AA epoxygenation have anti-inflammatory properties, this alteration may contribute to uncontrolled renal inflammation, which is a major cause of renal damage in dTGR. Key Words: rats Ⅲ kidney Ⅲ cytochrome P450 Ⅲ arachidonic acid Ⅲ angiotensin II Ⅲ inflammation Ⅲ end-organ damage C ytochrome P450 enzymes (P450/CYP) generate 2 major classes of arachidonic acid (AA) metabolites in the kidney, namely epoxyeicosatrienoic acids (5,6-, 8,9-, 11,12-, and 14,15-EETs) and hydroxyeicosatetraenoic acids (19-and 20-HETE). 1,2 In rat kidney, EET formation is catalyzed by P450 isoforms belonging to the CYP2C and CYP2J subfamilies. 3-5 CYP4A subfamily members produce 20-HETE. 6,7 Both EETs and 20-HETE contribute to the regulation of renal vascular tone and tubular sodium and water transport. 5,8,9 Impaired renal hemodynamics and increased salt retention was associated with altered EET-and 20-HETE-generating P450 expression in a number of hypertensive rat and mouse models. 10 -17 A recent study indicates that EETs may be important by acting as anti-inflammatory mediators in endothelial cells. 18 EETs were found to inhibit cytokine-induced activation of the nuclear transcription factor B (NF-B) and may thus prevent vascular inflammation at a very early stage. We have studied a double transgenic rat (dTGR) model, which harbors the human genes for renin and angiotensinogen. 19,20 dTGR develop hypertension associated with impaired renal hemodynamics and tubular sodium reabsorp...