Dinitrofluorobenzene Research Articles

Comprehensive analysis of phenotypes and transcriptome characteristics reveal the best atopic dermatitis mouse model induced by MC903

BackgroundAlthough several mouse models of exogenous-agent–induced atopic dermatitis (AD) are currently available, the lack of certainty regarding their similarity with human AD has limited their scientific value. Thus, comprehensive evaluation of the characteristics of mouse models and their similarity with human AD is essential. ObjectiveTo compare six different exogenous-agent–induced AD mouse models and find out the optimum models for study. MethodsFemale BALB/c mice underwent induction of AD-like dermatitis by MC903 alone or in combination with ovalbumin (OVA), dinitrofluorobenzene (DNFB) alone or in combination with OVA, OVA alone, or Staphylococcus aureus. Gross phenotype, total immunoglobulin E (IgE) level, histopathological manifestations, and skin lesion transcriptome were analyzed, and metagenomic sequencing of the gut microbiome was performed. ResultsThe DNFB plus OVA model showed the highest disease severity, while the OVA model showed the lowest severity. The MC903 and MC903 plus OVA models showed high expression of T-helper (Th)2- and Th17-related genes; the DNFB and DNFB plus OVA models showed upregulation of Th1-, Th2-, and Th17-related genes; while the S. aureus inoculation model showed more enhanced Th1 and Th17 immune responses. In contrast to the other models, the OVA-induced model showed the lowest expression levels of inflammation-related genes, while the MC903 model shared the largest overlap with human AD profiles. The intestinal microbiota of all groups showed significant differences after modeling. ConclusionEach AD mouse model exhibited different characteristics. The MC903 model was the best to recapitulate most features of human AD among these exogenous-agent–induced AD models.

Sanger's reagent as a new general phototrigger for organelle imaging

Photoactivatable subcellular organelles imaging offers the desirable spatiotemporal resolution in studying the complex biological processes. Developing proper and simple photoremovable protecting groups (PPGs) is the key for constructing such imaging probes. In this study, we designed and synthesized three Sanger's reagent caged fluorescent probes for specific photoactivated organelle imaging. We showed the photoactivated fluorescence recovery of the probes. The photolysis mechanism was verified by mass spectra (MS) analysis, and the highly efficient photolysis process was monitored by high performance liquid chromatography (HPLC). The probes successfully imaged their respective targeted organelle, including mitochondria, lysosomes, and endoplasmic reticulum (ER), in a photoactivated manner, and exhibited high co-localization coefficients when compared to commercially available probes. Given the high reactivity and efficient photodissociation capability of Sanger's reagent with amino groups, our examples demonstrate the potential of Sanger's reagent as a novel general PPG for constructing photoactivatable fluorescent probes.

Role of creatine shuttle in colorectal cancer cells.

The creatine shuttle translocates the energy generated by oxidative phosphorylation to the cytoplasm via mitochondrial creatine kinase (MTCK) and creatine kinase B (CKB) in the cytoplasm. It is not apparent how the creatine shuttle is related to cancer. Here, we analyzed the expression and function of CKB and MTCK in colorectal cancer (CRC) and investigated the role of the creatine shuttle in CRC. Compared with normal mucosa, 184 CRC tissues had higher levels of CKB and MTCK, and these levels were associated with histological grade, tumor invasion, and distant metastasis. CK inhibitor dinitrofluorobenzene (DNFB) on CRC cell lines HT29 and CT26 inhibited cell proliferation and stemness to less than 2/3 and 1/20 of their control levels, respectively. In this treatment, the production of reactive oxygen species increased, mitochondrial respiration decreased, and mitochondrial volume and membrane potential decreased. In a syngeneic BALB/c mouse model using CT26 cells pretreated with DNFB, peritoneal metastasis was suppressed to 70%. Phosphorylation of EGFR, AKT, and ERK1/2 was inhibited in DNFB-treated tumors. High ATP concentrations prevented EGFR phosphorylation in HT29 cells following DNFB treatment, CKB or MTCK knockdown, and cyclocreatine administration. Despite not being immunoprecipitated, CKB and EGFR were brought closer together by EGF stimulation. These findings imply that blocking the creatine shuttle decreases the energy supply, suppresses oxidative phosphorylation, and blocks ATP delivery to phosphorylation signals, preventing signal transduction. These findings highlight the critical role of the creatine shuttle in cancer cells and suggest a potential new cancer treatment target.

Effect of Momordicacharantia polysaccharide on immunomodulatory activity in mice.

Momordica charantia polysaccharides (MCPs) have been reported to exert beneficial roles, such as disease healing, in medicine and pharmacy. However, little is known about their effects on immunomodulation. The present study aimed to explore the possible effects of Momordica charantia polysaccharide (MCP) on the immunomodulatory activity of mice lymphocytes. To this aim, male BALB/c mice aged 6-8 weeks were assigned to the following six experimental groups: i) Normal (NG); ii) model (MG); iii) positive (PG); iv) MCP low-dose (MLG); v) MCP medium-dose (MMG); and vi) MCP high-dose (MHG). An immunosuppressive model was established by the intraperitoneal injection of cyclophosphamide in all groups apart from NG. The NG and MG mice were fed with distilled water, whereas the PG mice were administered with levamisole and the MLG, MMG and MHG mice were fed on low, medium and high (100, 200 and 300 mg/kg, respectively) doses of MCP for 21 consecutive days. Subsequently, the mice underwent surgical procedure and were analysed using a range of procedures, including measurement of the thymus index (TI) and spleen index (SI), assessment of the lymphocyte proliferation rate and cell phagocytosis of peritoneal macrophages, lymphocyte proliferation, secretion and mRNA expression of cytokines IFN-γ, IL-6 and IL-12. The mice divided into six groups as mentioned above and treated for 7 days, in the first 6 days, except NG group, mice in each group were desiccated in the abdominal cavity and sensitized by 1% dinitrofluorobenzene (DNFB). On day 6, mice were sensitized with 20 µl DNFB/acetone/olive oil solution behind the right ear and in front of the right ear. Compared with those in the NG mice (not injected with 80 mg/kg cyclophosphamide), the TIs and SIs of the PG, MLG, MMG and MHG mice were increased. In addition, the inhibitory rate of ear swelling and the phagocytic activity of peritoneal macrophages in the PG, MLG, MMG and MHG mice were increased compared with those of MG. Furthermore, the lymphocyte proliferation rate, the secretion and relative mRNA expression levels of cytokines IFN-γ, IL-6 and IL-12 were significantly increased in the PG, MMG and MHG mice compared with those in the NG mice. The results from the present study suggest that treatment with MCP led to an upregulation of the organ indices of immunosuppressed mice, reduced their delayed allergic reaction indicated by the differential cytokine levels, improved the phagocytic activity of peritoneal macrophages, enhanced the proliferation rate of lymphocytes, increased the secretion and expression of IFN-γ, IL-6 and IL-12. Therefore, MCP may improve the immune function of the immunosuppressed mice.

Combined application of dinitrofluorobenzene and ovalbumin induced AD-like dermatitis with an increase in helper T-cell cytokines and a prolonged Th2 response

BackgroundThe progression of acute-to-chronic atopic dermatitis is accompanied by multiple helper T-cell cytokine responses, but the mechanisms and relative importance of these changes remain unclear. There is no animal model for atopic dermatitis that recapitulates these cytokine responses.ObjectiveWe sought to build a novel mouse model for atopic dermatitis (AD) that recapitulates these helper T-cell responses and some dynamic changes in cytokine responses in the progression of AD.MethodsFemale BALB/c mice were subjected to the application of dinitrofluorobenzene (DNFB) and ovalbumin (OVA) to induce AD-like dermatitis. Skin lesions and serum were collected from mice in the acute and chronic phases to detect changes in cytokine responses and other features of AD.ResultsCombined application of DNFB and OVA successfully induced AD-like dermatitis and histological changes as well as epidermal barrier dysfunction. In the acute phase of AD-like dermatitis, Th2-associated cytokines were mainly increased in serum and skin lesions. In the chronic phase of AD-like dermatitis, Th2-associated cytokines were still highly expressed, while Th1- and Th17-associated cytokines were also gradually increased. Compared with the acute phase, the JAK-STAT signaling pathway was highly expressed in the chronic phase of AD-like dermatitis.ConclusionThe combined application of DNFB and OVA could be used to build a new mouse model for atopic dermatitis. This mouse model recapitulates the helper T-cell responses and some dynamic changes in cytokine responses in the progression of acute-to-chronic in human AD. The JAK-STAT signaling pathway plays a pivotal role in the chronicity of AD.

Isothermal Titration Calorimetry for Characterizing the Zinc(II)‐Binding Properties of Photocaged Complexes with Micromolar Affinity

AbstractMorphDeCage (2‐(4‐methoxy‐3‐nitrophenyl)‐2‐morpholinoacetic acid) and PyrDeCage (2‐(4‐methoxy‐3‐nitrophenyl)‐2‐(methyl(pyridin‐2‐ylmethyl)amino)acetic) are Zn2+ photocages that utilize photodecarboxylation of the methoxy derivative of meta‐nitrophenylacetic acid as the release mechanism. Isothermal titration calorimetry (ITC) was used an alternative to usual approaches to measure the Zn2+ binding affinities of these new compounds owing to unsuccessful measurement by competitive titration with 4‐(2‐pyridylazo)resorcinol (PAR). MorphDeCage forms a 1 : 1 ligand‐metal complex with a 106 μM Kd value. PyrDeCage forms both a 1 : 1 and 1 : 2 metal: ligand complexes with 3.2 and 21.7 μM Kd values respectively. To further demonstrate the efficacy of the ITC methodology and provide a comparison to direct UV‐vis titrations data, two photocages based on Sanger's reagent (SRPs) were prepared. The Kd values of the SRPs measured by UV‐vis titration and ITC were internally consistent and support the retraction of the original report (J. Am. Chem. Soc. 2020, 142, 3806–3813), which was withdrawn due to errors in binding affinity measurements.

Calcium-Based Antimicrobial Peptide Compounds Attenuate DNFB-Induced Atopic Dermatitis-Like Skin Lesions via Th-Cells in BALB/c Mice.

Atopic dermatitis (AD) is a chronic and recurrent inflammatory skin disease, characterized by severe itching and recurrent skin lesions. We hypothesized that a novel treatment involving calcium-based antimicrobial peptide compounds (CAPCS), a combination of natural calcium extracted from marine shellfish, and a variety of antimicrobial peptides, may be beneficial for AD. We established a dinitrofluorobenzene (DNFB)-induced AD model in BALB/c mice to test our hypothesis. We observed mouse behavior and conducted histopathological and immunohistochemical analyses on skin lesions before and after CAPCS treatment. We also characterized the changes in the levels of cytokines, inflammatory mediators, and Toll-like receptors (TLRs) in plasma and skin lesions. The results showed that (i) topical application of CAPCS ameliorated AD-like skin lesions and reduced scratching behavior in BALB/c mice; (ii) CAPCS suppressed infiltration of inflammatory cells and inhibited the expression of inflammatory cytokines in AD-like skin lesions; (iii) CAPCS reduced plasma levels of inflammatory cytokines; and (iv) CAPCS inhibited TLR2 and TLR4 protein expression in skin lesions. Topical application of CAPCS exhibits a therapeutic effect on AD by inhibiting inflammatory immune responses via recruiting helper T cells and engaging the TLR2 and TLR4 signaling pathways. Therefore, CAPCS may be useful for the treatment of AD.

Tremella fuciformis polysaccharides alleviate induced atopic dermatitis in mice by regulating immune response and gut microbiota.

Atopic dermatitis (AD), characterized by severe pruritus, immune imbalance, and skin barrier dysfunction, has a high incidence worldwide. Recent evidence has shown that the modulation of gut microbiota is crucial for alleviating clinical symptoms of AD. Tremella fuciformis polysaccharides (TFPS) have been demonstrated to have a variety of biological activities such as immunomodulatory, anti-tumor, antioxidant, anti-inflammatory, neuroprotective, hypoglycemic and hypolipidemic effects. However, their effects on AD treatment have never been investigated. In this study, we compared the therapeutic effects of topical or oral administration of TFPS on AD in dinitrofluorobenzene (DNFB)-induced AD mice. Both topical application and oral administration of TFPS led to improvement on transdermal water loss, epidermal thickening, and ear edema in AD mice, but the oral administration showed significantly better efficacy than the topical application. The TFPS treatment increased the proportion of CD4 (+) CD25 (+) Foxp3 (+) regulatory T cells in mesenteric lymph nodes. Additionally, the non-targeted metabolomics and sequencing of 16S rDNA amplicons were performed, revealing metabolite modulation in feces and changed composition of gut microbiota in mice, which were induced for AD-like disorder and treated by oral administration of TFPS. Collectively, these data suggest that the oral administration of TFPS may constitute a novel effective therapy for AD, with underlying mechanisms associated with the regulation of immune response, and improvement of both metabolism and the composition of intestinal microbiota.

619 CP31398, which reverses UV-induced p53 mutations, does not undo ultraviolet radiation-induced immune suppression

Chronic, excessive exposure to solar ultraviolet radiation is the major causative agent for cutaneous squamous cell carcinomas. Mutations in p53 are essential for these cancers to develop. UV radiation is also immunosuppressive and is an additional requirement for UV-induced SCCs to develop. Mutations in p53 can be reversed with the compound CP31398, which results in fewer SCCs in mice exposed to a UV radiation skin carcinogenesis protocol. It is unknown whether p53 mutations contribute to photoimmunosuppression. The purpose of this study was to determine if the UV immunosuppressive effects could be reversed by pretreatment with CP31398. A local UVB regimen consisting of UVB radiation (200 mJ/cm2) for 4 days followed by sensitization with the hapten 2, 4, dinitrofluorobenzene (DNFB) was employed for photoimmunosuppression. To determine the role of CP-31398, we treated the shaved dorsal skin of C57BL/6 mice with CP-31398 (1.25 mg/mouse) or vehicle cream, 30 min before each UVB treatment. Treatment with CP-31398 did not abrogate the immunosuppressive effect of UV. These findings suggest that although p53 mutations are responsible for UV-induced SCCs, they are not necessary for UV-induced immunosuppression.

004 Calcitonin gene-related peptide (CGRP) acts on endothelial cells (ECs) at a site not in skin to favor th17-type immunity

The neuropeptide CGRP can influence the outcome of in vitro antigen presentation through actions on ECs acting as bystanders. To examine this pathway in vivo, we used an inducible, conditional knockout (KO) mouse with RAMP1 (part of the CGRP receptor) deleted on ECs. Upon skin immunization with dinitrofluorobenzene (DNFB), stimulated CD4+ T cells from draining lymph nodes (LNs) had significantly reduced IL-17A expression with significantly increased IFNγ and IL-22 expression at the protein and mRNA levels compared to control RAMP1 floxed, Cre- mice (Cre-).

An Atopic Dermatitis-Like Mouse Model by Alternate Epicutaneous Application of Dinitrofluorobenzene and an Extract of Dermatophagoides Farinae.

Several studies have tried to establish mice models of atopic dermatitis (AD) through the allergen of Dermatophagoides farinae (Df). However, there are no typical skin lesions after epicutaneous application of an extract of Df (DfE) on BALB/c mice. Dinitrofluorobenzene (DNFB) is a common hapten that brings about contact dermatitis. Skin dysfunction induced by DNFB may be a way to enhance the effects of DfE on mice skin. Thus, we hypothesized that alternate epicutaneous application of DNFB and DfE could induce AD-like skin lesions on BALB/c mice. To test this hypothesis, we alternately applied the DNFB and DfE to the back skin of BALB/c mice for 8 weeks. Changes in mice skin lesions and the frequency of scratching behavior were recorded. The variation of Th1-related cytokines (interferon-γ [IFN-γ] and interleukin two [IL-2]) and Th2-related cytokines (IL-4 and IL-13) was detected in serum and lesional skin. Eventually, the BALB/c mice developed severe erythema, erosion, scarring, and excoriation on the entire back, showing a high frequency of scratching behavior. In addition, Th2 cells' dominant cytokines appeared in both serum and lesional skin. Those results indicate that alternating epicutaneous exposure to DNFB and DfE can produce AD-like models with typical clinical features and Th2-type immune responses in BALB/c mice. This model could be valuable for studying the pathogenesis of AD and developing novel therapeutic agents for it.

Circadian rhythm affects the magnitude of contact hypersensitivity response in mice.

The circadian rhythm controls multiple biological processes, including immune responses; however, its impact on cutaneous adaptive immune response remains unclear. We used a well-established cutaneous type IV allergy model, contact hypersensitivity (CHS). We induced CHS using dinitrofluorobenzene (DNFB). Mice were sensitized and elicited with DNFB in the daytime or at night. In mice, a nocturnally active animal, we found that ear swelling increased when mice were sensitized at night compared with in the daytime. In addition, cell proliferation and cytokine production in the draining lymph nodes (LNs) were promoted when sensitized at night. We hypothesized that these differences were due to the oscillation of leukocyte distribution in the body through the circadian production of adrenergic hormones. Administration of a β2-adrenergic receptor (β2AR) agonist salbutamol in the daytime decreased the number of immune cells in blood and increased the number of immune cells in LNs. In contrast, a β2AR antagonist ICI18551 administration at night increased the number of immune cells in blood and decreased the number of immune cells in LNs. Accordingly, the severity of CHS response was exacerbated by salbutamol administration in the daytime and attenuated by ICI18551 administration at night. Our study demonstrated that the magnitude of adaptive CHS response depends on the circadian rhythm and this knowledge may improve the management of allergic contact dermatitis (ACD) in humans.

The medicinal mushroom Ganoderma lucidum attenuates UV-induced skin carcinogenesis and immunosuppression.

The medicinal mushroom Ganoderma lucidum is traditionally used for treating multiple diseases, including cancer. This study examined skin cancer preventive activity of a commercial product containing spore and fruiting body in 30:8 ratio (GLSF). Extracts of GLSF and spore component (GLS) were prepared using artificial gastrointestinal juice and examined on JB6 cells. GLSF and GLS dose-dependently inhibited epidermal growth factor-induced JB6 transformation at non-toxic concentrations. SKH-1 mice which were fed with diets containing GLSF (1.25%), GLS (0.99%) or the fruiting body (GLF) (0.26%) were exposed to chronic low-dose ultraviolet (UV) radiation to assess their effects on skin carcinogenesis. GLSF, but not GLS or GLF, reduced skin tumor incidence and multiplicity. In non-tumor skin tissues of mice, GLSF attenuated UV-induced epidermal thickening, expression of Ki-67, COX-2 and NF-κB, while in tumor tissues, GLSF increased expression of CD8 and Granzyme B. To examine the effects of GLSF on UV-induced immunosuppression, mice which were fed with GLSF were evaluated for the contact hypersensitivity (CHS) response to dinitrofluorobenzene (DNFB). GLSF significantly reversed UV-mediated suppression of DNFB-induced CHS by increasing CD8+ and decreasing CD4+ and FoxP3+ T-cells in mouse ears. Therefore, GLSF prevents skin cancer probably via attenuating UV-induced immunosuppression.

Exploration of Nitroaromatic Antibiotics via Sanger’s Reagent: Synthesis, In Silico, and Antimicrobial Evaluation

Facile synthesis of molecular hybrids containing a 2,4-dinitrophenyl moiety was achieved via nucleophilic aromatic substitution of the fluoride anion of Sanger’s reagent (2,4-dinitrofluorobenzene) with various N, S, and O nucleophiles, considered as bioactive moieties. Antimicrobial evaluation of the new hybrids was carried out using amoxicillin and nystatin as antibacterial and antifungal reference standards, respectively. MIC test results identified the compounds 3, 4, and 7 as the most active hybrids against standard strains and multidrug-resistant strains (MDR) of Staphylococcus aureus, Escherichia coli, and Pseudomonas aurginosa. Most of the hybrids displayed two times the antibacterial activity of AMOX against MDR Pseudomonas aeruginosa, E. coli, and a standard strain of P. aeruginosa (ATCC 29853), while demonstrating a weak antifungal profile against Candida albicans. Selectivity profiles of the promising compounds 3, 4, 6, 7, 8, and 11 on WI-38 human cells were characterized, which indicated that compound 3 is the safest one (CC50 343.72 μM). The preferential anti-Gram-negative activity of our compounds led us to do docking studies on DNA gyrase B. Docking revealed that the potential antimicrobial compounds fit well into the active site of DNA gyrase B. Furthermore, in silico absorption, distribution, metabolism, and excretion (ADME) predictions revealed that most of the new compounds have high gastrointestinal absorption and a good oral bioavailability with no BBB permeability.

Type I Interferons Enhance the Repair of Ultraviolet Radiation-Induced DNA Damage and Regulate Cutaneous Immune Suppression.

Type I interferons (IFNs) are important enhancers of immune responses which are downregulated in human cancers, including skin cancer. Solar ultraviolet (UV) B radiation is a proven environmental carcinogen, and its exposure contributes to the high prevalence of skin cancer. The carcinogenic effects of UV light can be attributed to the formation of cyclobutane pyrimidine dimers (CPD) and errors in the repair and replication of DNA. Treatment with a single dose of UVB (100 mJ/cm2) upregulated IFNα and IFNβ in the skin of C57BL/6 mice. IFNα and IFNβ were predominantly produced by CD11b+ cells. In mice lacking the type I IFN receptor 1 (IFNAR1), the repair of CPD following cutaneous exposure to a single dose of UVB (100 mJ/cm2) was decreased. UVB induced the expression of the DNA repair gene xeroderma pigmentosum A (XPA) in wild-type (WT) mice. In contrast, such treatment in IFNAR1 (IFNAR1-/-) mice downregulated XPA. A local UVB regimen consisting of UVB radiation (150 mJ/cm2) for 4 days followed by sensitization with hapten 2,4, dinitrofluorobenzene (DNFB) resulted in significant suppression of immune responses in both WT and IFNAR1-/- mice. However, there were significantly higher CD4+CD25+Foxp3+ regulatory T-cells in the draining lymph nodes of IFNAR1-/- mice in comparison to WT mice. Overall, our studies reveal a previously unknown action of type I IFNs in the repair of photodamage and the prevention of UVB-induced immune suppression.

Dual Electrode Detection in LC‐EC Analysis of Sanger‐tagged Amino Acids: Electrochemical Reduction of Aromatic Nitro Groups

AbstractAnalysis of amino acids is crucial to protein structure elucidation. Amino acids, amenable to separation by liquid chromatography (LC), can be detected by sensitive detectors used in liquid chromatograph including absorbance, fluorescence or electrochemical detector when derivatized. Derivatization of amino acids using suitable reagents enhances the separation and detection of amino acids using liquid chromatography. Sanger's reagent (1‐fluoro‐2,4‐dinitrobenzene, DNFB) makes amino acids suitable for absorbance detection. However, little has been done in terms of liquid chromatography with electrochemical detection (LC‐EC) of the DNFB derivatized amino acids. Furthermore, sensor development based on electrochemistry of nitroaromatics has increased dramatically for explosive detection. Since nitroaromatics are electrochemically active, it is essential to determine the reduction pathway. Cyclic voltammetry (CV), rotating disk electrode (RDE) and rotating ring disk electrode (RRDE) experiments have been performed on nitrobenzene (NB) and N‐methyl‐2,4‐dinitroaniline (NMDNA). The results showed that the nitro group was reduced to hydroxylamine in aqueous solutions by addition of four electrons and four protons per nitro group and the hydroxylamine can be reversibly oxidized into a nitroso by removal of two electrons and two protons. Electrochemical detection of the nitro groups is appropriate for dual electrode detection of DNFB labeled amino acids in which reduction can occur on an upstream electrode and corresponding oxidation of the reduction product occurs on the downstream electrode.

Anti-allergy Effect of Sulfated Polysaccharide from Sargassum polycystum on Dinitrofluorobenzene Induced Allergic Contact Dermatitis in Mice

Background: Sargassum polycystum C. Agardh has potent antioxidant and antiinflammatory properties. However, its anti-allergic effect has not yet been reported. In this study, we investigated the anti-allergic effects of sulfated polysaccharide of S. polycystum (SPSP) in Dinitrofluorobenzene (DNFB)- induced allergic contact dermatitis animal model. Methods: SPSP was extracted through the hot water extraction method and was subjected to compositional analyses. For the Allergic Contact Dermatitis (ACD) model, symptoms were induced by the topical application of 0.5% DNFB on the shaved ventral skin of mice. SPSP (500, 1000, and 2000 mg/kg) and Prednisolone were orally administered for seven days after sensitization. Elicitation was performed seven days later with 0.2% DNFB. After this, ear thickness was measured at baseline and 24 hours post elicitation using a dial thickness gauge. Serum of mice was obtained 24 hours post elicitation, and the level of IFNγ and TNFα was quantified by enzyme-linked immunosorbent assays (ELISA). Results: SPSP afforded 33.6% carbohydrates, 23.7% sulfate, 7.5% protein, and 1.5% uronic acid contents. SPSP inhibited the ear swelling and cytokines (IFNγ and TNFα) production in DNFBinduced mice in a dose-dependent manner. In comparison with Prednisolone (p>0.05), the highest concentration (2000 mg/kg) of SPSP showed a comparable anti-allergic effect. Conclusion: These findings showed that the sulfated polysaccharide from S. polycystum is a potential natural source to treat allergic contact dermatitis. The effect is attributed to the polysaccharideprotein complex present in the extract, but further studies are needed to establish the exact mechanism of action of SPSP in the treatment of the disease.

Diet-induced obesity aggravates NK cell-mediated contact hypersensitivity reaction in Rag1-/- mice.

Previous studies showed that natural killer (NK) cells mediate contact hypersensitivity (CHS) reaction. Many reports are showing that obesity promotes several inflammatory diseases. It was shown that diet-induced obesity (DIO) aggravates classical T cell-mediated CHS in mice. To determine whether the high-fat diet (HFD)-induced obesity modulates antigen-specific NK cell-mediated response. We evaluated the effect of DIO on NK cell-mediated CHS reaction using a model of dinitrofluorobenzene (DNFB)-induced CHS in Rag1-/- mice. Rag1-/- mice fed HFD for 8 but not for 4 weeks developed aggravated CHS reaction determined by ear swelling measurement when compared to animals kept on normal diet (ND) prior to DNFB sensitization. The obese Rag1-/- mice presented the adipose tissue inflammation. Furthermore, in vitro analysis showed that feeding with HFD significantly increases interferon γ (IFN-γ) and interleukin (IL)-12p70 and decreases adiponectin concentration in liver mononuclear cell (LMNC) culture supernatants. The flow cytometry analysis of LMNC revealed that HFD treatment prior to DNFB sensitization increases the percentage of NK1.1+ IFN-γ+ cell population and affects the development and maturation of NK1.1+ cells. In summary, current results suggest that the DIO significantly modulates the local and systemic inflammatory response, contributing to exacerbation of the CHS response mediated by liver NK cells.

501 Administration of nicotinamide riboside (NR) or pterostilbene (PT) to mice inhibits suppression of contact hypersensitivity (CHS) by mid-range ultraviolet radiation (UVR)

Topical administration of PT inhibits some acute effects of mid-range UVR (UVBR, 280-320 nm) in mouse skin and oral nicotinamide reduces the rate of new non-melanoma skin cancers in high-risk patients. NR+PT inhibits UVBR-induced tissue swelling in mice and does so more effectively than either agent at the dose tested. We have now asked if NR, PT or the combination can inhibit UVBR suppression of CHS in 2 models. In the low-dose model, mice receive a UVBR dose too low to cause gross changes in skin, followed by immunization at the irradiated site, resulting in suppressed CHS. In the high-dose model, mice receive a dose sufficient to cause gross skin changes followed by immunization at an unirradiated site, also with suppressed CHS. C3H mice were placed in groups that were fed standard diet/water or chow containing 0.08% PT, water with 0.4% NR or both for 4 wks. In low-dose experiments, mice in each group had their dorsa shaved and depilated. Half in each group were exposed to 1,700 J/m2 of UVBR daily for 4 d while the other half were mock-irradiated. Mice were immunized on the exposed dorsum with 25 μl of 0.5% dinitrofluorobenzene (DNFB) 4 h after the last irradiation. Mice were challenged 7 d later with 10 μl of 0.2% DNFB to each ear and 24-h ear swelling assessed. CHS in mice not given PT, NR or both was significantly reduced by UVBR exposure compared to mock-irradiated mice. In mice fed NR, PT, or both the UVBR effect was significantly less pronounced. In a preliminary high-dose experiment, groups of mice were treated similarly except that a single dose of 10,000 J/m2 of radiation was administered and immunization was performed on the unirradiated shaved abdomen 3 d later. In this experiment, the UVBR effect was also significantly less pronounced in the NR, PT or NR+PT groups. NR and PT both inhibited UVB-induced immune suppression at the doses administered as did the combination.

Capsaicin attenuates immunosuppression induced by chronic stress in BALB/C mice

Although acute stress generally exerts positive effects on the immune system, chronic stress typically causes immunosuppression via the hypothalamic–pituitary–adrenal (HPA) axis. In this study, the effects of capsaicin (1.28 mg/kg intraperitoneally [i.p.] for 7 days) on immune parameters were evaluated under conditions of chronic stress. Capsaicin treatment significantly increased the immune response as evaluated by the delayed-type hypersensitivity (DTH) reaction to dinitrofluorobenzene (DNFB) and splenocyte proliferation assays- It also is able to rescue the splenocytes of the apoptosis induced by stress. The capsaicin treatment increased the production of Th1 cytokines and decreased the production of Th2 cytokines and TGF-β1 in the plasma and culture supernatants of immunosuppressed mice, which is associated with the modulation of Th2 induced by stress cells. Moreover, the production of corticosterone significantly decreased in capsaicin-treated animals as compared to control groups. The capsaicin treatment further attenuated the immunosuppression induced by the corticosterone treatment (40 mg/kg i.p. for 7 days), albeit less potently, as exhibited in the DTH response. Intriguingly, the capsaicin treatment decreased the induction of IL-10, IL-4, and TGF-β1 through high doses of corticosterone, indicating direct cellular immunomodulation. These results show, that capsaicin is able to modulate chronic stress-induced immunosuppression, mediating corticosterone released inhibition, but also, that capsaicin significantly modulates the pharmacological action of corticosterone in vivo.