Does Exposure to UV Radiation Induce a Shift to a Th-2-like Immune Reaction?

In addition to being the primary cause of skin cancer, UV radiation is immune suppressive and there appears to be a link between the ability of UV to suppress the immune response and induce skin cancer. Cytokines made by UV-irradlated keratinocytes play an essential role in activating immune suppression. In particular, we have found that keratinocyte-derlved interleukin (IL)-10 is responsible for the systemic impairment of antigenpresenting cell function and the UV-induced suppression of delayed-type hypersensitivity (DTH). Antigen presentation by splenic adherent cells isolated from UV-irradiated mice to T helper-1 type T (Th1) cells is suppressed, whereas antigen presentation to T helper-2 type T (Th2) cells is enhanced. The enhanced antigen presentation to Th2 cells and the impaired presentation to Th1 cells can be reversed in vivo by injecting the UV-irradiated mice with monoclonal anti-IL-10 antibody. Furthermore, immune suppression can be transferred from UV-irradiated mice to normal recipients by adoptive transfer of T cells. Injecting the recipient mice with anti-IL-4 or anti-IL-10 prevents the transfer of immune suppression, suggesting the suppressor cells are Th2 cells. In addition, injecting UV-irradiated mice with IL-12, a cytokine that has been shown to be the primary inducer of Th1 cells, and one that prevents the differentiation of Th2 cells in vivo, reverses UV-induced immune suppression. These findings support the hypothesis that UV exposure activates IL-10 secretion, which depresses the function of Th1 cells, while enhancing the activity of Th2 cells.     

Modulation effect of Semen Ziziphi Spinosae extracts on IL-1β, IL-4, IL-6, IL-10, TNF-α and IFN-γ in mouse serum

This study aims to explore and evaluate the effects of Semen Ziziphi Spinosae extracts on the serum levels of interleukin (IL)-6, IFN-γ, IL-1β, TNF-α, IL-10 and IL-4 in mice, and the regulative effect of Semen Ziziphi Spinosae on the cytokine system. Using an ELISA assay, the serum levels of IL-6, IFN-γ, IL-1β, TNF-α, IL-10 and IL-4 were examined in mice after intraperitoneal injection (i.p.) with Semen Ziziphi Spinosae extracts. The results showed that the levels of IL-6 and IL-1β were significantly increased compared with the control groups (p<0.01), while the level of tumour necrosis factor-α (TNF-α) was significantly decreased (p<0.01). Semen Ziziphi Spinosae possesses certain modulation effects on cytokines, and the immuno-regulating function and hypnosis effects of Semen Ziziphi Spinosae may be relevant to these modulation effects on cytokines.     

Inhibition of UV-induced immune suppression and interleukin-10 production by plant oligosaccharides and polysaccharides

Application of Aloe barbadensis poly/oligosaccharides to UV-irradiated skin prevents photosuppression of delayed-type hypersensitivity (DTH) responses in mice. We tested the hypothesis that these carbohydrates belong to a family of biologically active, plant-derived polysaccharides that can regulate responses to injury in animal tissues. C3H mice were exposed to 5 kJ/m2 UVB from unfiltered FS40 sunlamps and treated with between 1 pg and 10 micrograms tamarind xyloglucans or control polysaccharides methylcellulose or dextran in saline. The mice were sensitized 3 days later with Candida albicans. Tamarind xyloglucans and purified Aloe poly/oligosaccharides prevented suppression of DTH responses in vivo and reduced the amount of interleukin (IL)-10 observed in UV-irradiated murine epidermis. Tamarind xyloglucans were immunoprotective at low picogram doses. In contrast, the control polysaccharides methylcellulose and dextran had no effect on immune suppression or cutaneous IL-10 at any dose. Tamarind xyloglucans and Aloe poly/oligosaccharides also prevented suppression of immune responses to alloantigen in mice exposed to 30 kJ/m2 UVB radiation. To assess the effect of the carbohydrates on keratinocytes, murine Pam212 cells were exposed to 300 J/m2 UVB radiation and treated for 1 h with tamarind xyloglucans or Aloe poly/oligosaccharides. Treatment of keratinocytes with immunoprotective carbohydrates reduced IL-10 production by approximately 50% compared with the cells treated with UV radiation alone and completely blocked suppressive activity of the culture supernatants in vivo. The tamarind xyloglucans also blocked UV-activated phosphorylation of SAPK/JNK protein but had no effect on p38 phosphorylation. These results indicate that animals, like plants, may use carbohydrates to regulate responses to environmental stimuli.     

Enhancement of cutaneous immune response to bacterial infection after low-level light therapy with 1072 nm infrared light: a preliminary study

We investigated the photobiomodulation effects of 1072 nm infrared light on the natural immune response involved in anti-bacterial and wound healing processes. Thirty mice infected with MRSA on the skin were divided into two groups. The experimental group was treated with 1072 nm infrared light (irradiance: 20 mW/cm(2), fluence: 12 J/cm(2) for 10 min) at 2, 4, 8, 12, 24 h, 3 and 5 days after inoculation and the control group with sham light. Serial changes of the mRNA levels of TLR2, IL-1β, TNF-α, IL-6, iNOS, MCP-1, TGF-β, bFGF and VEGF were studied by real time RT-PCR and those of the expression level of VEGF, bFGF, TGF-β and NF-κB by immunohistochemistry. The mRNA levels of the cytokines involved in the early phase of anti-bacterial immune response (IL-1β, TNF-α, IL-6, MCP-1) increased significantly in the 1072 nm group, peaking between 12 and 24 h post-inoculation. These levels normalized after 3-5 days. Immunohistochemistry revealed a notably stronger expression of VEGF in the 1072 nm group from 8-h post-inoculation to 5-day post-inoculation. We concluded that 1072 nm infrared light had a photobiomodulation effect which resulted in an enhanced biological immune response to the bacterial infection by MRSA and also increased the expression of VEGF to a significant level.     

EXPOSURE OF MICE TO UV-B RADIATION SUPPRESSES DELAYED HYPERSENSITIVITY TO Candida albicans

Groups of mice were exposed to a single dose of UV radiation before or after immunization with Candida albicans. The delayed type hypersensitivity (DTH) response was markedly depressed in all UV-irradiated groups. Exposure of mice to UV radiation before sensitization induced splenic suppressor cells that, upon transfer to normal recipients, impaired the induction of DTH to Candida. In contrast, exposure of mice to UV radiation after sensitization interfered with elicitation of the DTH response, but this suppression was not transferable. These studies demonstrate that immunity to Candida albicans in mice is impaired by exposure to UV radiation and that two separate mechanisms may be involved.     

TGF-β-signaling with small molecule FKBP12 antagonists that bind myristoylated FKBP12-TGF-β type I receptor fusion proteins

Background: Growth arrest in many cell types is triggered by transforming growth factor beta (TGF-β), which signals through two TGF-β receptors (type I, TGF-βRI, and type II, TGF-βRII). In the signaling pathway, TGF-β binds to the extracellular domain of TGF-βRII, which can then transphosphorylate TGF-βRI in its glycine/serine (GS)-rich box. Activated TGF-βRI phosphorylates two downstream effectors, Smad2 and Smad3, leading to their translocation into the nucleus. Cell growth is arrested and plasminogen activator inhibitor 1 (PAI-1) is upregulated. We investigated the role of the immunophilin FKBP12, which can bind to the GS box of TGF-βRI, in TGF-β signaling.Results: Overexpression of myristoylated TGF-βRI and TGF-βRII cytoplasmic tails caused constitutive nuclear translocation of a green-fluorescent-protein-Smad2 construct in COS-1 cells, and constitutive activation of a PAI-1 reporter plasmid in mink lung cells. Fusing FKBP12 to TGF-βRI resulted in repression of autosignaling that could be alleviated by FK506M or rapamycin (two small molecules that can bind to FKBP12). Mutation of the FKBP12-binding site in the FKBP12-TGF-βRI fusion protein restored constitutive signaling. An acidic mutation in the FKBP12-TGFβRI protein allowed FKBP12 antagonists to activate signaling in the absence of TGF-βRII. Further mutations in the TGF-βRI FKBP12-binding site resulted in TGF-β signaling that was independent of both TGF-βRII and FKBP12 antagonists.Conclusions: Fusing FKBP12 to TGF-βRI results in a novel receptor that is activated by small molecule FKBP12 antagonists. These results suggest that FKBP12 binding to TGF-βRI is inhibitory and that FKBP12 plays a role in inhibiting TGF-β superfamily signals.     

Solid Phase Extraction of Urinary Polypeptide Growth Factors Using Methyl Bonded Silica in Free Suspension

Abstract

Methyl bonded silica effectively concentrates EGF, TGF-α, and TGF-β from urine. Fractional elution of the sorbent with aqueous acetonitrile released approximately 70 to 80% of the EGF at between 25 and 30% acetonitrile, 80% of TGF-α between 15 and 25% acetonitrile and 70% of TGF-β between 30 and 50% acetonitrile. Enrichment in a single step was 1400 fold for EGF, 200 fold for TGF-α, and 250 fold for TGF-β. Further chromatography on sizing gel, carboxymethyl cellulose, and HPLC provided complete separation of TGF-α from the much more abundant but bioactively similar EGF.     

Identification of novel small molecule TGF-β antagonists using structure-based drug design

Aberrant transforming growth factor-β (TGF-β) signalling has been associated with a number of disease pathologies, such as the development of fibrosis in the heart, lung and liver, cardiovascular disease and cancer, hence the TGF-β pathway represents a promising target for a variety of diseases. However, highly specific ways to inhibit TGF-β signalling need to be developed to prevent cross-talk with related receptors and minimise unwanted side effects. We have used used virtual screening and molecular docking to identify small molecule inhibitors of TGF-β binding to TßRII. The crystal structure of TGF-β3 in complex with the extracellular domain of the type II TGF-β receptor was taken as a starting point for molecular docking and we developed a structure-based pharmacophore model to identify compounds that competitively inhibit the binding of TGF-β to TβRII and antogonize TGF-β signalling. We have experimentally tested 67 molecules suggested by in silico screening and similarity searching for their ability to inhibit TGF-β signalling in TGF-β-dependent luciferase assays in vitro and the molecule with the strongest inhibition had an IC₅₀ of 18 μM. These compounds were selected to bind to the SS1 subsite (composed of F30, C31, D32, I50, T51 S52, I53, C54 and E55) of TßRII and all share the general property of being aromatic and fairly flat. Molecular dynamics simulations confirmed that this was the most likely binding mode. The computational methods used and the hits identified in this study provide an excellent guide to medicinal chemistry efforts to design tighter binding molecules to disrupt the TGF-β/TßRII interaction.     

Rottlerin enhances IL-1β-induced COX-2 expression through sustained p38 MAPK activation in MDA-MB-231 human breast cancer cells

Cyclooxygenase-2 (COX-2) is an important enzyme in inflammation. In this study, we investigated the underlying molecular mechanism of the synergistic effect of rottlerin on interleukin1β (IL-1β)-induced COX-2 expression in MDA-MB-231 human breast cancer cell line. Treatment with rottlerin enhanced IL-1β-induced COX-2 expression at both the protein and mRNA levels. Combined treatment with rottlerin and IL-1β significantly induced COX-2 expression, at least in part, through the enhancement of COX-2 mRNA stability. In addition, rottlerin and IL-1β treatment drove sustained activation of p38 Mitogen-activated protein kinase (MAPK), which is involved in induced COX-2 expression. Also, a pharmacological inhibitor of p38 MAPK (SB 203580) and transient transfection with inactive p38 MAPK inhibited rottlerin and IL-1β-induced COX-2 upregulation. However, suppression of protein kinase C δ (PKC δ) expression by siRNA or overexpression of dominant-negative PKC δ (DN-PKC-δ) did not abrogate the rottlerin plus IL-1β-induced COX-2 expression. Furthermore, rottlerin also enhanced tumor necrosis factor-α (TNF-α), phorbol myristate acetate (PMA), and lipopolysaccharide (LPS)-induced COX-2 expression. Taken together, our results suggest that rottlerin causes IL-1β-induced COX-2 upregulation through sustained p38 MAPK activation in MDA-MB-231 human breast cancer cells.     

Anti-inflammatory activity of methyl salicylate glycosides isolated from Gaultheria yunnanensis (Franch.) Rehder

Gaultheria yunnanensis (Franch.) Rehder is a kind of traditional Chinese herbal medicine used for the treatments of rheumatoid arthritis, swelling and pain. Two methyl salicylate glycosides, namely methyl benzoate-2-O-β-D-xylopyranosyl(1-6)-O-β-D-gluco-pyranoside (J12122) and methyl benzoate-2-O-β-D-xylopyranosyl(1-2)[O-β-D-xylopyranosyl(1-6)]-O-β-D-glucopyranoside (J12123), are natural salicylic derivatives isolated from Gaultheria yunnanensis. In this study, we investigated the anti-inflammatory activity of J12122 and J12123 on LPS-induced RAW264.7 macrophage cells by measuring the production of pro-inflammatory cytokines, accumulation of nitric oxide (NO), and level of reactive oxygen species (ROS). The results showed that both methyl salicylate glycosides dose-dependently inhibited the production of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6, respectively. Consistent with these observations, J12122 and J12123 significantly suppressed the accumulation of NO, with an inhibitory rate of 56.20% and 51.72% at 3.0 μg/mL concentration, respectively. Furthermore, the two methyl salicylate glycosides reduced the level of ROS induced by LPS. These results showed that the isolated compounds possess anti-inflammatory properties through inhibition the production pro-inflammatory cytokines, NO, and ROS.     

Viability of the antigen determines whether DNA or urocanic acid act as initiator molecules for UV-induced suppression of delayed-type hypersensitivity

UV radiation suppresses the immune response, and UV-induced immune suppression contributes to UV-induced photocarcinogenesis. For UV-induced immune suppression to occur, electromagnetic energy (i.e. UV radiation) must be converted to a biological signal. Two photoreceptors have been identified in the skin that serves this purpose, epidermal DNA and trans-urocanic acid (UCA). Although compelling evidence exists to support a role for each pathway (UV-induced DNA damage or photoisomerization of UCA) in UV-induced immune suppression, it is not clear what determines which photoreceptor pathway is activated. To address this question, we injected UV-irradiated mice with a monoclonal antibody with specificity for cis-UCA or applied liposomes containing DNA repair enzymes to the skin of UV-irradiated mice. The effect that each had on UV-induced suppression of delayed-type hypersensitivity was measured. We asked whether the light source used (FS-40 sunlamps vs solar-simulated UV radiation) altered whichever pathway of immune suppression was activated. Different doses of UV radiation and the viability of the antigen were also considered. Neither the dose of UV nor the light source had any influence on determining which pathway was activated. Rather, we found that the viability of the antigen was the critical determinant. When live antigens were used, UV-induced immune suppression was blocked with monoclonal anti-cis-UCA but not with T4 endonuclease V-containing liposomes. The reverse was observed when formalin-fixed or killed antigens were used. Our findings indicate that antigen viability dictates which photoreceptor pathway predominates after UV exposure.     

In vitro migration capacity of human adipose tissue-derived mesenchymal stem cells reflects their expression of receptors for chemokines and growth factors

The homing properties of adipose tissue-derived mesenchymal stem cells (AdMSCs) have stimulated intravenous applications for their use in stem cell therapy. However, the soluble factors and corresponding cellular receptors responsible for inducing chemotaxis of AdMSCs have not yet been reported. In the present study, the migration capacity of human AdMSCs (hAdMSCs) toward various cytokines or growth factors (GFs) and the expression of their receptors were determined. In a conventional migration assay, PDGF-AB, TGF-β1, and TNF-α showed the most effective chemoattractant activity. When AdMSCs were preincubated with various chemokines or GF, and then allowed to migrate toward medium containing 10% FBS, those preincubated with TNF-α showed the highest migratory activity. Next, hAdMSCs were either preincubated or not with TNF-α, and allowed to migrate in response to various GFs or chemokines. Prestimulation with TNF-α increased the migration activity of hAdMSCs compared to unstimulated hAdMSCs. When analyzed by FACS and RT-PCR methods, hAdMSCs were found to express C-C chemokine receptor type 1 (CCR1), CCR7, C-X-C chemokine receptor type 4 (CXCR4), CXCR5, CXCR6, EGF receptor, fibroblast growth factor receptor 1, TGF-β receptor 2, TNF receptor superfamily member 1A, PDGF receptor A and PDGF receptor B at both the protein and the mRNA levels. These results indicate that the migration capacity of hAdMSCs is controlled by various GFs and chemokines. Prior in vitro modulation of the homing capacity of hAdMSCs could stimulate their movement into injured sites in vivo when administered intravenously, thereby improving their therapeutic potential.     

UROCANIC ACID ANALOGUES AND THE SUPPRESSION OF THE DELAYED TYPE HYPERSENSITIVITY RESPONSE TO Herpes simplex VIRUS

Ultraviolet irradiated urocanic acid (4-imidazoleacrylic acid) containing a mixture of cis- and trans-isomers has been shown previously to induce suppression of the delayed type hypersensitivity (DTH) response to Herpes simplex virus type 1 (HSV-1) in a murine model of infection. The cis-isomer of urocanic acid was prepared and the cis- and trans-isomers of 2-methylurocanic acid. 2-pyrroleacrylic acid, 2-furanacrylic acid, 2-thiopheneacrylic acid, 3-thiopheneacrylic acid as well as dihydrourocanic acid and histamine. Each was applied at concentrations of 1 and 50 micrograms per mouse to the shaved dorsal skin and the mice were infected subcutaneously with HSV 5 h later. After 8-10 days the DTH response to the virus was measured by an ear swelling test. It was found that cis-urocanic acid was effective in suppressing the DTH response at levels of 1 microgram per mouse or less. The cis- and trans-isomers of 2-furanacrylic acid, 2-pyrroleacrylic acid and 2-thiopheneacrylic acid were also effective, with the cis- form generally being more active than trans, and 2-pyrroleacrylic acid being particularly potent. Cis- and trans-3-thiopheneacrylic acid, on the other hand, were only marginally immunosuppressive while neither isomer of 2-methylurocanic acid had any suppressive ability. Dihydrourocanic acid and histamine were also shown to suppress the DTH response. Thus the structural features necessary for urocanic acid and its analogues to act as mediators of UV-induced immunosuppression could be deduced and implications for their mechanism of action discussed.     

Enhancement of Protective Effects of <Emphasis Type="Italic">Radix Scutellariae</Emphasis> on UVB-induced Photo Damage in Human HaCaT Keratinocytes

Radix Scutellariae (RS) has long been used in the treatment of inflammatory and allergic diseases. Its main flavonoids, baicalin (BG) and wogonoside (WG), can be hydrolyzed into their corresponding aglycones, baicalein (B) and wogonin (W). In this study, we developed a safe and effective method of transforming these glycosides using Peclyve PR. The transformation rate of BG and WG reached 98.5 and 98.1%, respectively, with 10% enzyme at 40 °C for 60 h. Furthermore, we compared the anti-photoaging activity of RS before and after enzyme treatment, as well as their respective main components, in UVB-irradiated HaCaT cells. Results found that enzyme-treated RS (ERS) appeared to be much better at preventing UVB-induced photoaging than RS. ERS significantly inhibited the upregulation of matrix metalloproteinase-1 and IL-6 caused by UVB radiation by inactivating the MAPK/AP-1 and NF-κB/IκB-α signaling pathways. ERS treatment also recovered UVB-induced reduction of procollagen type I by activating the TGF-β/Smad pathway. In addition, ERS exhibited an excellent antioxidant activity, which could increase the expression of cytoprotective antioxidants such as HO-1 and NQ-O1, by facilitating Nrf2 nuclear transfer. These findings demonstrated that the photoprotective effects of RS were significantly improved by enzyme-modified biotransformation.     

Inhibition of inflammatory mediators by neobavaisoflavone in activated RAW264.7 macrophages

Flavonoids and coumarins are the major bioactive constituents identified in Psoralea corylifolia. The active fraction isolated from fruits, seeds and roots possesses antibacterial, antioxidative and immunomodulatory properties. Neobavaisoflavone is one of the flavonoids found in Psoralea corylifolia. In the present study we investigated in vitro the anti-inflammatory activity of neobavaisoflavone. Macrophages play an important role in inflammation through the release of inflammatory mediators involved in the immune response. Inappropriate and prolonged macrophage activation is largely responsible for the pathology of acute and chronic inflammatory conditions. Neobavaisoflavone significantly inhibited the production of reactive oxygen species (ROS), reactive nitrogen species (RNS) and cytokines: IL-1β, IL-6, IL-12p40, IL-12p70, TNF-α in LPS+IFN-γ- or PMA- stimulated RAW264.7 macrophages.     

CXCR4 inhibition suppresses Cd-induced renal oxidative stress,apoptosis, and fibrosis by inhibiting the TGF-β1/Smad pathway

This study aimed to investigate the role and mechanism of CXC chemokine receptor 4 (CXCR4) in cadmium (Cd)-induced renal injury. CXCR4 and TGF-β1/Smad pathway protein levels were detected by western blotting. Indicators related to renal function and oxidative stress factors were assessed and reactive oxygen species (ROS) level was evaluated by staining. TUNEL was used to measure apoptosis rate. PAS and Masson's trichrome staining were used to detect the level of renal fibrosis. The expression of Bcl-2, Bax, Cleaved-caspase 3, fibronectin, and collagen I proteins were detected by western blotting, immunohistochemistry, or immunofluorescence. The expression of CXCR4 was increased in a Cd-induced chronic renal injury model in rats. Si-CXCR4 decreased levels of TGF-β1, TGF-βR1, p-Smad2/Smad2, p-Smad3/Smad3, the renal weight index, urine protein, blood urea nitrogen, blood creatinine, and levels of MDA but raised the levels of SOD and GSH-Px. In addition, si-CXCR4 inhibited apoptosis in Cd-treated rats. CXCR4 inhibition alleviated fibrosis levels in Cd-treated rats. In Cd-treated cells, TGF-β attenuated the suppressive effect of CXCR4 inhibition on the TGF-β1/Smad pathway. TGF-β intervention increased MDA and ROS, and downregulated SOD and GSH-Px. TGF-β attenuated the inhibitory effect of CXCR4 on apoptosis and fibrosis. CXCR4 inhibition decreased levels of Cd-induced renal oxidative stress, apoptosis, and fibrosis by inhibiting the TGF-β1/Smad pathway.     

PHOTOREVERSAL OF ABNORMAL MORPHOGENESIS IN SEA-URCHIN EMBRYOS CAUSED BY UV-IRRADIATION

Abstract— Morphological abnormalities induced by UV-irradiation of 8- or 16-cell-stage embryos of the sea-urchin, Hemicentrotus pulchenimus , and their photoreversal were studied. UV-irradiation of the animal hemisphere of embryos caused the formation of exogastrulae, while that of the vegetal hemisphere caused the formation of permanent blastulae. These UV-induced morphological abnormalities were photoreversed when the UV-irradiated embryos were subsequently illuminated with visible light, so that the UV-irradiated embryos developed into normal pluteus-larvae. When UV-irradiated embryos were illuminated with visible light up to the onset of the DNA-synthesis phase of the following cell cycle, the UV-induced morphological abnormalities were photoreversed almost completely. The effectiveness of an exposure to visible light declined thereafter and was subsequently completely lost.     

Inflammasome Activation of IL-1 Family Mediators in Response to Cutaneous Photodamage(†)

Although keratinocytes are relatively resistant to ultraviolet radiation (UVR) induced damage, repeated UVR exposure result in accumulated DNA mutations that can lead to epidermal malignancies. Keratinocytes play a central role in elaborating innate responses that lead to inflammation and influence the generation of adaptive immune responses in skin. Apart from the minor cellular constituents of the epidermis, specifically Langerhans cells and melanocytes, keratinocytes are the major source of cytokines. UVR exposure stimulates keratinocytes to secrete abundant pro-inflammatory IL-1-family proteins, IL-1α, IL-1β, IL-18, and IL-33. Normal skin contains only low levels of inactive precursor forms of IL-1β and IL-18, which require caspase 1-mediated proteolysis for their maturation and secretion. However, caspase-1 activation is not constitutive, but dependents on the UV-induced formation of an active inflammasome complex. IL-1 family cytokines can induce a secondary cascade of mediators and cytokines from keratinocytes and other cells resulting in wide range of innate processes including infiltration of inflammatory leukocytes, induction of immunosuppression, DNA repair or apoptosis. Thus, the ability of keratinocytes to produce a wide repertoire of proinflammatory cytokines can influence the immune response locally as well as systematically, and alter the host response to photodamaged cells. We will highlight differential roles played by each IL-1 family molecule generated by UV-damaged keratinocytes, and reveal their complementary influences in modulating acute inflammatory and immunological events that follow cutaneous UV exposure.