Pan HDACi Valproic Acid and Trichostatin A Show Apparently Contrasting Inflammatory Responses in Cultured J774A.1 Macrophages

This study was initiated as an attempt to clarify some of the apparent conflicting data regarding the so-called anti-inflammatory versus proinflammatory properties of histone deacetylase inhibitors (HDACis). In cell culture, typically, chronic pretreatment with the HDACi valproic acid (VPA) and trichostatin A (TSA) exhibits an anti-inflammatory effect. However, the effect of acute treatment with VPA and TSA on the levels of inflammatory cytokines in J774A.1 macrophage cell line is unknown. Therefore, this study investigated the effect of acute treatment with VPA and TSA on levels of key inflammatory cytokines in maximally stimulated J774A.1 cells. J774A.1 macrophages were treated with either VPA or TSA for 1 h (acute treatment), followed by maximal stimulation with LPS + IFNγ for 24 h. ELISA was used to measure the levels of proinflammatory cytokines TNFα, NO and IL-1β from the culture medium. Acute treatment with VPA showed a dose-dependent increase in levels of all three cytokines. Similar to VPA, TSA also showed a dose-dependent increase in levels of IL-1β alone. This study sheds new light on the conflicting data in the literature that may partly be explained by acute or short-term exposure versus chronic or long-term exposure to HDACi.

Identification of stable reference genes for lipopolysaccharide-stimulated macrophage gene expression studies

Gene expression studies which utilize lipopolysaccharide (LPS)-stimulated macrophages to model immune signaling are widely used for elucidating the mechanisms of inflammation-related disease. When expression levels of target genes are quantified using Real-Time quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR), they are analyzed in comparison to reference genes, which should have stable expression. Judicious selection of reference genes is, therefore, critical to interpretation of qRT-PCR results. Ideal reference genes must be identified for each experimental system and demonstrated to remain constant under the experimental conditions. In this study, we evaluated the stability of eight common reference genes: Beta-2-microglobulin (B2M), Cyclophilin A/Peptidylprolyl isomerase A, glyceraldehyde-3-phosphatedehydrogenase (GAPDH), Hypoxanthine Phosphoribosyltransferase 1, Large Ribosomal Protein P0, TATA box binding protein, Ubiquitin C (UBC), and Ribosomal protein L13A. Expression stability of each gene was tested under different conditions of LPS stimulation and compared to untreated controls. Reference gene stabilities were analyzed using C_t value comparison, NormFinder, and geNorm. We found that UBC, closely followed by B2M, is the most stable gene, while the commonly used reference gene GAPDH is the least stable. Thus, for improved accuracy in evaluating gene expression levels, we propose the use of UBC to normalize PCR data from LPS-stimulated macrophages.

Cell-SELEX-based selection and characterization of a G-quadruplex DNA aptamer against mouse dendritic cells

Targeting of dendritic cells (DCs) by aptamers increases antigen capture and presentation to the immune system. Our aim was to produce aptamers against DC molecules using the cell-SELEX procedure. For this purpose, 18 rounds of cell-SELEX were performed on mouse macrophage J774A.1 and CT26 as target and control cells, respectively. The selected aptamers were truncated and their binding to mouse macrophages, and immature and mature DCs analyzed. Two macrophage-specific aptamers, Seq6 and Seq7, were identified. A truncated form of Seq7, Seq7-4, 33 nucleotides in length and containing the G-quadruplex, bound macrophages and immature DCs with KD values in the nanomolar range. We anticipate that Seq7-4 has potential as a therapeutic tool in targeting of mouse macrophages and immature DCs to efficiently improve different immunotherapy approaches.

Synthesis, characterization, and antileishmanial activities of gold(I) complexes involving quinoline functionalized N-heterocyclic carbenes

A series of new mononuclear cationic or neutral gold(I) complexes containing quinoline functionalized N-heterocyclic carbene(s) (NHC(s)) were synthesized and fully characterized by spectroscopic methods. The X-ray structures of two key compounds are presented. Proligands and their corresponding gold(I) complexes together with previously described silver(I) and gold(I) bis(NHC-quinoline) and gold(I) bis(NHC-methylbipyridine) complexes were evaluated in vitro towards Leishmania infantum. In parallel, the in vitro cytotoxicity of these molecules was assessed on the murine macrophages J774A.1. All gold(I) compounds show potent antileishmanial activity against L. infantum promastigotes and three of them are also efficient against L. infantum intracellular amastigotes. Structure-activity and toxicity relationships enables to evidence a lead-compound (6) displaying both a high activity and a good selectivity index.

The effects of WW2/WW3 domains of Smurf2 molecule on TGF-β signaling and arginase I gene expression

Smad ubiquitination regulatory factor 2 (Smurf2) consists of multiple WW domains which can interact with Smad7 molecule and inhibit signaling of transforming growth factor-beta (TGF-β) cytokine. Arginase I (ArgI) is one of the main products of TGF-β signaling that plays important roles in tumor escape and airway tissue fibrosis and remodeling in asthma. In this study, the effects of TAT fused to WW2/WW3 (TAT-WW2/WW3) recombinant protein on TGF-β signaling and ArgI gene expression were evaluated on J774A.1 cell culture. For this purpose, interaction of TAT-WW2/WW3 with Smad7, mRNA expression of ArgI, and phosphorylated Smad3 (P-Smad3) were analyzed in TAT-WW2/WW3-treated J774A.1 cell. The results showed interaction of TAT-WW2/WW3 with Smad7, downregulation of ArgI gene expression (P < 0.05), and higher amount of P-Smad3 in the TAT-WW2/WW3-treated cells. In conclusion, we suggest that TAT-WW2/WW3 could interfere with TGF-β signaling and reduce ArgI gene expression. Since, ArgI has important effects on tissue remodeling in asthma and cancer progression, so these findings could be used to develop a new approach in the treatment of asthma and cancers.

Synthesis of genistein coupled with sugar derivatives and their inhibitory effect on nitric oxide production in macrophages

The isoflavone genistein 1 and some derivatives modulate IL-12, TNF-α and NO production by macrophages and lung cancer cell lines, and improve the clinical signs of experimental autoimmune encephalomyelitis (EAE). Seven genistein derivatives connected at C-6 position of a sugar, such as d-glucose and d-galactose, were synthesized. The ability to modulate macrophage response was evaluated, showing variable inhibition capacity of NO and TNF-α production in J774.A1 and RAW 264.7. Five of the seven compounds were non-cytotoxic; compound 8 was more effective to inhibit NO and TNF-α production, without affecting cell viability.

Expression of an innate immune element (mouse hepcidin-1) in baculovirus expression system and the comparison of its function with synthetic human hepcidin-25

Hepcidin is an innate immune element which decreases the iron absorption from diet and iron releasing from macrophage cell. In contrast to the chemical iron chelators, there has been limited effort applied to the specific use of hepcidin as a new drug for decreasing the iron overload. Hepcidin is produced in different biological systems. For instance, E-coli is used for human hepcidin expression, however, post-translational modification is impaired. We have used a simple baculovirus expression system (BES) to improve the hepcidin folding and activity. Hepcidin Messenger Ribonucleic acid (mRNA) was isolated from mouse liver cells and its complementary Deoxyribonucleic acid (cDNA) was produced and amplified. PFastBac HTB vector was used for recombinant bacmid production. Recombinant baculovirus was produced using SF-9 cell line. The mouse hepcidin-1 protein was expressed in a large quantity and functional tests were performed for this recombinant peptide. The yield of hepcidin in BES was 20 μg/mL and anti-histidine (anti-His) tag antibody was used for the confirmation of hepcidin on western blot nitrocellulose paper. Functional tests showed that mouse hepcidin accumulates iron in the macrophage cell line J774A.1 up to 63%. In addition, our data showed that the mouse hepcidin-1 has less toxicity compared to the synthetic human hepcidin-25 (p = 0.000).