Acetylcholine production by group 2 innate lymphoid cells promotes mucosal immunity to helminths

Innate lymphoid cells (ILCs) are critical mediators of immunological and physiological responses at mucosal barrier sites. Whereas neurotransmitters can stimulate ILCs, the synthesis of small-molecule neurotransmitters by these cells has only recently been appreciated. Group 2 ILCs (ILC2s) are shown here to synthesize and release acetylcholine (ACh) during parasitic nematode infection. The cholinergic phenotype of pulmonary ILC2s was associated with their activation state, could be induced by in vivo exposure to extracts of Alternaria alternata or the alarmin cytokines interleukin-33 (IL-33) and IL-25, and was augmented by IL-2 in vitro. Genetic disruption of ACh synthesis by murine ILC2s resulted in increased parasite burdens, lower numbers of ILC2s, and reduced lung and gut barrier responses to Nippostrongylus brasiliensis infection. These data demonstrate a functional role for ILC2-derived ACh in the expansion of ILC2s for maximal induction of type 2 immunity.

Hydroxylated Chalcones as Aryl Hydrocarbon Receptor Agonists: Structure-Activity Effects

Hydroxylated chalcones are phytochemicals which are biosynthetic precursors of flavonoids and their 1,3-diaryl-prop-2-en-1-one structure is used as a scaffold for drug development. In this study, the structure-dependent activation of aryl hydrocarbon receptor (AhR)-responsive CYP1A1, CYP1B1 and UGT1A1 genes was investigated in Caco2 colon cancer cells and in non-transformed young adult mouse colonocytes (YAMC) cells. The effects of a series of di- and trihydroxychalcones as AhR agonists was structure-dependent with maximal induction of CYP1A1, CYP1B1 and UGT1A1 in Caco2 cells observed for compounds containing 2,2′-dihydroxy substituents and this included 2,2′-dihydroxy-, 2,2′,4′-trihydroxy- and 2,2′,5′-trihydroxychalcones. In contrast, 2′,4,5′-, 2′3′,4′-, 2′,4,4′-trihydroxy, and 2′,3-, 2′,4-, 2′,4′-, and 2′,5-dihydroxychalcones exhibited low to non-detectable AhR activity in Caco2 cells. In addition, all of the hydroxychalcones exhibited minimal to non-detectable activity in YAMC cells, whereas 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced CYP1A1, CYP1B1 and UGT1A1 in Caco2 and YAMC cells. The activity of AhR-active chalcones was confirmed by determining their effects in AhR-deficient, Caco2 cells. In addition, 2,2′-dihydroxychalcone induced CYP1A1 protein and formation of an AhR-DNA complex in an in vitro assay. Simulation and modeling studies of hydroxylated chalcones confirmed their interactions with the AhR ligand binding domain and was consistent with their structure-dependent activity as AhR ligands. Thus, this study identifies hydroxylated chalcones as AhR agonists with potential for these phytochemicals to impact AhR mediated colonic pathways.

P1817DOES EPIGENETIC FACTORS LIKE HDAC2 PLAYS ROLE IN STEROID RESISTANCE VIA REGULATION OF P-GP AND MRP-1 IN CHILDHOOD IDIOPATHIC NEPHROTIC SYNDROME?

Background and Aims The action of glucocorticoids is to switch off activated inflammatory genes. The activated glucocorticoid receptors (GR) interact with co-repressor molecules to impair NFκB-associated co-activator activity, reducing histone acetylation, chromatin remodelling. Reduction in histone acetylation occurs via recruitment of histone deacetylase (HDAC) 2 to the activated inflammatory gene complex by activated GR, resulting in efficacious suppression of activated inflammatory genes within the nucleus. To evaluate the effect HDAC 2 on P-gp and MRP-1 expression and function. Method Total of 78 subjects were considered in the study out of which 50 were steroid sensitive nephrotic syndrome (SSNS), and 28 were steroid resistant nephrotic syndrome (SRNS) patients. mRNA expression was analyzed on peripheral blood mononuclear cells (PBMCs) in SRNS patients (mean age 8.43±3.8 years), SSNS patients (mean age 7.54±3.5 years). PBMCs were treated with 1µM of Theophylline (HDAC2 stimulator) and 0.8µM of Trichostatin A (HDAC2 inhibitor) for a period of 48 hours. Quantitative PCR was performed using light cycler LC480 using SYBR green PCR technology with SYBR premix relative gene expression levels were calculated and normalized to the corresponding levels of the housekeeping gene (GAPDH). Results Expression of P-gp (4.79±0.970 v/s 2.13±0.72, p<0.0001) and MRP-1 (3.99 ±0.8 v/s 1.99 ±0.91, p<0.0001) on PBMCs was increased in SRNS as compared to that of SSNS. HDAC2 mRNA levels were significantly decreased in SRNS patients as compared to that of SSNS patients (2.97 ± 0.95 v/s 6.02 ± 1.13, p<0.0001). Theophylline(HDAC stimulator) for a period of 48 hours decreased mRNA levels of P-gp and MRP-1 in PBMCs of SRNS with maximal induction at 1µM (fold change 2.65 and 2.21, *p<0.0001) However HDAC2 mRNA expression increased significantly (fold change5.67, *p<0.0001). In SSNS patients P-gp and MRP-1 mRNA expression decreased at1µM (fold change 1.25, 1.24, *p<0.0001) while the mRNA expression was increased (fold change 6.93, *p<0.0001). TSA(HDAC inhibitor) for a period of 48 hours increased mRNA levels of P-gp and MRP-1 in PBMCs of SRNS with maximal induction at 0.8µM (fold change 7.51, 7.31, *p<0.0001) and significantly decreased the level of HDAC2 (fold change1.50, *p<0.0001) similarly in SSNS patients P-gp and MRP-1 mRNA expression increased at 0.8µM (fold change 3.49, 3.35, *p<0.0001) and HDAC2 decreased (fold change2.53, *p<0.0001) at 0.8µM. The functional activity of P-gp and MRP-1 was significantly higher in SRNS group as compared to SSNS group (p<0.001), whereas enzymatic activity of HDAC2 was increased in SSNS group as compared to SRNS group (p<0.001) Conclusion As we observed that HDAC2 regulates P-gp and MRP-1 efflux pumps, Inducer of HDAC2 may be a probable treatment stratergy for patients of Idiopathic Nephrotic Syndrome.

Dal81 Regulates Expression of Arginine Metabolism Genes inCandida parapsilosis

ABSTRACTFungi can use a wide variety of nitrogen sources. In the absence of preferred sources such as ammonium, glutamate, and glutamine, secondary sources, including most other amino acids, are used. Expression of the nitrogen utilization pathways is very strongly controlled at the transcriptional level. Here, we investigated the regulation of nitrogen utilization in the pathogenic yeastCandida parapsilosis. We found that the functions of many regulators are conserved with respect toSaccharomyces cerevisiaeand other fungi. For example, the core GATA activatorsGAT1andGLN3have a conserved role innitrogencataboliterepression (NCR). There is one ortholog ofGZF3andDAL80, which represses expression of genes in preferred nitrogen sources. The regulatorsPUT3andUGA3are required for metabolism of proline and γ-aminobutyric acid (GABA), respectively. However, the role of the Dal81 transcription factor is distinctly different. InS. cerevisiae, Dal81 is a positive regulator of acquisition of nitrogen from GABA, allantoin, urea, and leucine, and it is required for maximal induction of expression of the relevant pathway genes. InC. parapsilosis, induction of GABA genes is independent of Dal81, and deletingDAL81has no effect on acquisition of nitrogen from GABA or allantoin. Instead, Dal81 represses arginine synthesis during growth under preferred nitrogen conditions.IMPORTANCEUtilization of nitrogen by fungi is controlled bynitrogencataboliterepression (NCR). Expression of many genes is switched off during growth on nonpreferred nitrogen sources. Gene expression is regulated through a combination of activation and repression. Nitrogen regulation has been studied best in the model yeastSaccharomyces cerevisiae. We found that although many nitrogen regulators have a conserved function inSaccharomycesspecies, some do not. The Dal81 transcriptional regulator has distinctly different functions inS. cerevisiaeandC. parapsilosis. In the former, it regulates utilization of nitrogen from GABA and allantoin, whereas in the latter, it regulates expression of arginine synthesis genes. Our findings make an important contribution to our understanding of nitrogen regulation in a human-pathogenic fungus.

Efficacy, long-term toxicity, and mechanistic studies of gold nanorods photothermal therapy of cancer in xenograft mice

Gold nanorods (AuNRs)-assisted plasmonic photothermal therapy (AuNRs-PPTT) is a promising strategy for combating cancer in which AuNRs absorb near-infrared light and convert it into heat, causing cell death mainly by apoptosis and/or necrosis. Developing a valid PPTT that induces cancer cell apoptosis and avoids necrosis in vivo and exploring its molecular mechanism of action is of great importance. Furthermore, assessment of the long-term fate of the AuNRs after treatment is critical for clinical use. We first optimized the size, surface modification [rifampicin (RF) conjugation], and concentration (2.5 nM) of AuNRs and the PPTT laser power (2 W/cm2) to achieve maximal induction of apoptosis. Second, we studied the potential mechanism of action of AuNRs-PPTT using quantitative proteomic analysis in mouse tumor tissues. Several death pathways were identified, mainly involving apoptosis and cell death by releasing neutrophil extracellular traps (NETs) (NETosis), which were more obvious upon PPTT using RF-conjugated AuNRs (AuNRs@RF) than with polyethylene glycol thiol-conjugated AuNRs. Cytochrome c and p53-related apoptosis mechanisms were identified as contributing to the enhanced effect of PPTT with AuNRs@RF. Furthermore, Pin1 and IL18-related signaling contributed to the observed perturbation of the NETosis pathway by PPTT with AuNRs@RF. Third, we report a 15-month toxicity study that showed no long-term toxicity of AuNRs in vivo. Together, these data demonstrate that our AuNRs-PPTT platform is effective and safe for cancer therapy in mouse models. These findings provide a strong framework for the translation of PPTT to the clinic.

Clinical Pharmacodynamic Markers and Combinations with SY1425 (tamibarotene) in a Genomically-Defined Subset of Non-APL AML

SY-1425, a potent and selective agonist of the retinoic acid receptor RARα, is being investigated in a Ph2 trial in a novel genomically-defined subset of non-APL AML and MDS patients (clinicaltrials.gov NCT02807558). RARa is a nuclear hormone receptor and transcription factor that regulates genes involved in cell differentiation and proliferation. We identified a super-enhancer (SE) at the RARA locus, the gene encoding RARa, in a subset of primary non-APL AML blasts. Preclinical models demonstrated a correlation between the presence of a RARA SE and sensitivity to SY-1425, providing the rationale for clinical investigation. Further research has investigated pharmacodynamics (PD) markers and combinations of drugs to support clinical development of SY-1425. In this study we identified DHRS3mRNA induction as a measure of RARα target engagement with SY-1425. We also demonstrated synergy in preclinical models with SY-1425 and hypomethylating agents. Since RARα is a transcription factor that regulates target genes when bound by a retinoid, we characterized the dynamic expression changes of a panel of RARA enhancer- high and - low non-APL AML cell lines (hereafter referred to as RARA-high and -low) in response to SY-1425 treatment. DHRS3 showed the largest expression increase following treatment in 3 RARA-high cell lines, with a range of 29 to 115 fold. In contrast, there was a much lower DHRS3 induction in 3 RARA-low cell lines (range of 1.6 to 6.1 fold). Induction was found to be both time- and dose-dependent with maximal induction at approximately 6 hours and half maximal induction near the EC50 for the anti-proliferative effect in RARA-high cell lines. DHRS3 encodes dehydrogenase/reductase (SDR family) member 3, a metabolic enzyme involved in maintaining cellular retinol homeostasis and had previously been shown to be induced by retinoids. Thus, DHRS3induction in tumor cells represents a potentially useful PD marker for clinical studies of SY-1425. To better understand the mechanism of induction of DHRS3 by SY-1425 we examined the chromosomal localization of RARα as well as the epigenomic state of the DHRS3 locus by ChIP-seq for RARα and H3K27 acetylation, the latter being an indicator of active enhancers and promoters. In the untreated state, OCI-AML3 (a typical RARA-high AML cell line) was found to have multiple RARα binding sites both within and distal to the DHRS3 gene but minimal H3K27 acetylation. Following treatment with SY-1425, the level of H3K27 acetylation at DHRS3 increased, resulting in the formation of a SE. Moreover, the SE encompassed the RARα binding sites, consistent with the model in which SY-1425 converts RARα into an activator of DHRS3expression. Similar results were seen for the CD38 locus in which SY-1425 treatment increased expression, H3K27 acetylation, and RARα binding. CD38 is a cell surface antigen and marker of myeloid maturation readily analyzed by FACS analysis, suggesting it could be an additional PD marker to be used in clinical studies. Indeed, it was found that SY-1425 induced CD38 cell surface expression at similar levels in RARA-high AML cell lines and the NB-4 APL cell line, but not in RARA-low cell lines. We also investigated combinations of SY-1425 with approved or investigational AML and MDS agents in in vitro and in vivo models to inform future clinical studies and to further explore potential PD markers unique to the combined action of the drugs. Several standard of care agents and drugs in current development were found to have synergistic interactions with SY-1425 in RARA-high but not RARA-low cell lines. In particular, azacitidine and decitabine each showed strong in vitro synergy with SY-1425. Evaluation of SY-1425 plus azacitidine in a RARA-high PDX model of non-APL AML demonstrated a better response compared to either agent alone. Additional genome-wide ChIP-seq and expression studies of RARA-high cells treated with various combinations are being investigated to identify optimal PD markers for these combinations. These studies support the use of DHRS3 mRNA induction in tumor cells as a PD marker in the recently initiated Ph2 study of SY-1425 in genomically-defined non-APL AML and MDS patients (clinicaltrials.gov NCT02807558) and further exploration as a PD marker for future combination studies. Disclosures McKeown: Syros Pharmaceuticals: Employment, Equity Ownership. Fiore:Syros Pharmaceuticals: Employment, Equity Ownership. Lee:Syros Pharmaceuticals: Employment, Equity Ownership. Eaton:Syros Pharmaceuticals: Employment, Equity Ownership. Fritz:Syros Pharmaceuticals: Employment, Equity Ownership.

Release of siRNA from Liposomes Induced by Curcumin

Liposomes are a potential carrier of small interfering RNA (siRNA) for drug delivery systems (DDS). In this study, we searched for a molecule capable of controlling the release of siRNA from a certain type of liposomes and found that curcumin could induce the release of siRNA from the liposomes encapsulating siRNA within 30 min. However, the release of siRNA from the liposomes by curcumin showed a unique dose-response (i.e., bell-shaped curve) with a maximal induction at around 60 μg/ml of curcumin. Liposomal lipid compositions and temperatures influenced the efficiency in the release of siRNA induced by curcumin. About 10% of curcumin at a 60 μg/ml dose was incorporated into the liposomes within 30 min under our experimental conditions. Our results suggest a possibility that curcumin is useful in controlling the permeability of liposomes carrying large molecules like siRNA.

A novel RARα/CAR-mediated mechanism for regulation of human organic solute transporter-β gene expression

The organic solute transporter-α/β (OSTα/β) is a heteromeric transporter that is essential for bile acid and sterol disposition and for the enterohepatic circulation. To better understand the mechanism underlying OST gene regulation, the effects of retinoic acid (RA) on OSTα/β gene expression were investigated. The results show a dose-dependent induction of OSTβ but not OSTα expression in both Huh7 and HepG2 cells by RA treatment. A novel functional RA receptor response element (RARE; so-called DR5) in the promoter of OSTβ gene was identified. The interaction of RARα/RXRα with the RARE was verified by electrophoretic mobility shift and chromatin immunoprecipitation assays and its functional importance by hOSTβ promoter activation in luciferase reporter assays. The studies demonstrated that the RARE is also a constitutive androstane receptor (CAR) binding site for OSTβ gene regulation. These results suggest that OSTβ is a target of both FXR-mediated (by binding to IR-1 element) and RARα- and CAR-mediated (by binding to DR5 element) gene regulation pathways. In summary, this study has uncovered a novel RARE (DR5) element in the promoter of OSTβ that binds RARα or CAR heterodimerized with RXRα and appears to function synergistically with the IR-1 element to provide maximal induction of OSTβ in response to RA. These findings demonstrate a role for RARα and CAR in controlling OSTβ expression levels.

Sp1 trans-activates and is required for maximal aldosterone induction of the αENaC gene in collecting duct cells

The epithelial Na+ channel (ENaC) in the distal nephron constitutes the rate-limiting step for renal sodium reabsorption. Aldosterone increases tubular sodium absorption in large part by increasing αENaC transcription in collecting duct principal cells. We previously reported that Af9 binds to +78/+92 of αENaC and recruits Dot1a to repress basal and aldosterone-sensitive αENaC transcription in mouse inner medullary collecting duct (mIMCD)3 cells. Despite this epigenetic repression, basal αENaC transcription is still evident and physiologically necessary, indicating basal operation of positive regulators. In the present study, we identified Sp1 as one such regulator. Gel shift and antibody competition assays using a +208/+240 probe revealed DNA-Sp1-containing complexes in mIMCD3 cells. Mutation of the +222/+229 element abrogated Sp1 binding in vitro and in promoter-reporter constructs stably expressed in mIMCD3 cells. Compared with the wild-type promoter, an αENaC promoter-luciferase construct with +222/+229 mutations exhibited much lower activity and impaired trans-activation in Sp1 overexpression experiments. Conversely, Sp1 knockdown inhibited endogenous αENaC mRNA and the activity of the wild-type αENaC promoter but not the mutated construct. Aldosterone triggered Sp1 recruitment to the αENaC promoter, which was required for maximal induction of αENaC promoter activity and was blocked by spironolactone. Sequential chromatin immunoprecipitation assays and functional tests of +78/+92 and +222/+229 αENaC promoter mutants indicated that while Sp1, Dot1a, and Af9 co-occupy the αENaC promoter, the Sp1 effects are functionally independent from Dot1a and Af9. In summary, Sp1 binding to a cis-element at +222/+229 represents the first identified constitutive driver of αENaC transcription, and it contributes to maximal aldosterone trans-activation of αENaC.