Alterations of immune functions in barrier disrupted skin by UVB irradiation

Protective effect of Schizandrin B against damage of UVB irradiated skin cells depend on inhibition of inflammatory pathways

Schizandrin B is extracted from Schisandra chinensis (Turcz.) Baill. This study evaluated the photoprotective effect of Schizandrin B on oxidative stress injury of the skin caused by UVB-irradiation and the molecular mechanism of the photoprotective effect of Schizandrin B, and we firstly found that Schizandrin B could block Cox-2, IL-6 and IL-18 signal pathway to protect damage of skin cells given by UVB-irradiation. In the research, we found that Schizandrin B can attenuate the UVB-induced toxicity on keratinocytes and dermal fibroblasts in human body, and can outstandingly eliminated intracellular ROS produced by UVB-irradiation. These results demonstrate that Schizandrin B can regulate the function of decreasing intracellular SOD's activity and increasing the expression level of MDA in HaCaT cells result from the guidance of UVB, and it markedly reduced the production of inflammatory factors such as Cox-2, IL-6 or IL-18, decreased the expression level of MMP-1, and interdicted degradation process of collagens in UVB-radiated cells. Therefore, skin keratinocytes can be effectively protected from UVB-radiated damage by Schizandrin B, and UVB-irradiation caused inflammatory responses can be inhibited by attenuating process of ROS generating.

Local cortisol/corticosterone activation in skin physiology and pathology

Cortisol and corticosterone are the endogenous glucocorticoids (GCs) in humans and rodents, respectively. Systemic GC is released through the hypothalamic-pituitary-adrenal (HPA) axis in response to various stressors. Over the last decade, extra-adrenal production/activation of cortisol/corticosterone has been reported in many tissues. The enzyme that catalyzes the conversion of hormonally inactive cortisone/11-dehydrocorticosterone (11-DHC) into active cortisol/corticosterone in cells is 11β-hydroxysteroid dehydrogenase (11β-HSD). The 11β-HSD1 isoform is predominantly a reductase, which catalyzes nicotinamide adenine dinucleotide phosphate hydrogen-dependent conversion of cortisone/11-DHC to cortisol/corticosterone, and is widely expressed and present at the highest levels in the liver, lungs, adipose tissues, ovaries, and central nervous system. The 11β-HSD2 isoform, which catalyzes nicotinamide adenine dinucleotide⁺-dependent inactivation of cortisol/corticosterone to cortisone/11-DHC, is highly expressed in distal nephrons, the colon, sweat glands, and the placenta. In healthy skin, 11β-HSD1 is expressed in the epidermis and in dermal fibroblasts. On the other hand, 11β-HSD2 is expressed in sweat glands but not in the epidermis. The role of 11β-HSD in skin physiology and pathology has been reported recently. In this review, we summarize the recently reported role of 11β-HSD in the skin, focusing on its function in cell proliferation, wound healing, inflammation, and aging.

The human papillomavirus type 16 E7 oncoprotein induces a transcriptional repressor complex on the Toll-like receptor 9 promoter

HPV16-positive cervical cancer lesions contain NFκB–ERα nuclear complexes to repress the TLR9 promoter.

Human papillomavirus type 16 (HPV16) and other oncogenic viruses have been reported to deregulate immunity by suppressing the function of the double-stranded DNA innate sensor TLR9. However, the mechanisms leading to these events remain to be elucidated. We show that infection of human epithelial cells with HPV16 promotes the formation of an inhibitory transcriptional complex containing NF-κBp50–p65 and ERα induced by the E7 oncoprotein. The E7-mediated transcriptional complex also recruited the histone demethylase JARID1B and histone deacetylase HDAC1. The entire complex bound to a specific region on the TLR9 promoter, which resulted in decreased methylation and acetylation of histones upstream of the TLR9 transcriptional start site. The involvement of NF-κB and ERα in the TLR9 down-regulation by HPV16 E7 was fully confirmed in cervical tissues from human patients. Importantly, we present evidence that the HPV16-induced TLR9 down-regulation affects the interferon response which negatively regulates viral infection. Our studies highlight a novel HPV16-mediated mechanism that combines epigenetic and transcriptional events to suppress a key innate immune sensor.

Enhanced anti-tumor immunity by superantigen-pulsed dendritic cells

Staphylococcal enterotoxins A (SEA) and B (SEB) are classical models of superantigens (SAg), which induce potent T-cell-stimulating activity by forming complexes with MHC class II molecules on antigen-presenting cells. This large-scale activation of T-cells is accompanied by increased production of cytokines such as interferon-γ (IFN-γ). Additionally, as we previously reported, IFN-γ-producing CD8(+) T cells act as "helper cells," supporting the ability of dendritic cells to produce interleukin-12 (IL-12)p70. Here, we show that DC pulsed with SAg promote the enhancement of anti-tumor immunity. Murine bone marrow-derived dendritic cells (DC) were pulsed with OVA(257-264) (SIINFEKL), which is an H-2Kb target epitope of EG7 [ovalbumin (OVA)-expressing EL4] cell lines, in the presence of SEA and SEB and were subcutaneously injected into naïve C57BL/6 mice. SAg plus OVA(257-264)-pulsed DC vaccine strongly enhanced peptide-specific CD8(+) T cells exhibiting OVA(257-264)-specific cytotoxic activity and IFN-γ production, leading to the induction of protective immunity against EG7 tumors. Furthermore, cyclophosphamide (CY) added to SAg plus tumor-antigens (OVA(257-264), tumor lysate, or TRP-2) pulsed DC immunization markedly enhanced tumor-specific T-cell expansion and had a significant therapeutic effect against various tumors (EG7, 2LL, and B16). Superantigens are potential candidates for enhancing tumor immunity in DC vaccines.

Broad-band ultraviolet B phototherapy in zoster patients may reduce the incidence and severity of postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia (PHN) is one of the common complications of herpes zoster infection, particularly in the elderly. Current therapeutic measures are only partially effective in the affected patients. As inflammatory mediators released by different cells play an important role in the pathogenesis of this neuropathic pain and with regard to the immunomodulatory effects of ultraviolet B (UVB) spectrum, we presumed that UVB phototherapy might be effective in the prevention of PHN.

METHOD

This study was performed in two phases. Phase I was a prospective open controlled trial. Twenty-five patients with severe pain in the first 7 days of zoster rash were divided into two groups: the prevention group (n=12) received oral acyclovir (800 mg five times a day for 10 days) plus broad-band UVB to the affected dermatomes, starting with 20 mJ/cm(2) and gradually increasing the dose by 10 mJ/cm(2) each session to a maximum dose of 100 mJ/cm(2). Treatment sessions were repeated three times a week until pain relief or to a maximum of 15 sessions. The control group (n=13), who had disease characteristics similar to the prevention group, received only oral acyclovir with the same dose. All patients reported their severity of pain on a verbal rating scale (VRS, score 0-4) before treatment and at 1 and 3 months' follow-up. In phase II of the study, five patients with established PHN (more than 3 months after rash onset) received UVB with the above-mentioned protocol.

RESULTS

A total of 17 patients older than 40 (10 females, seven males; mean age, 65.5 years; range: 47-82 years) who had intractable pain due to zoster infection received UVB in two phases of the study. In patients who received phototherapy in the first 7 days of rash, 58.33% and 83.33% were completely pain free at 1-and 3-month follow-up, respectively. The corresponding figure in the control group was significantly lower (38.46% at 1 month and 53.85% at 3 months). The severity of pain was also lower in the phototherapy group than the control group (mean VRS 2.50 vs. 3.28 at 3 months). None of the patients who were treated more than 3 months after rash onset (established PHN) experienced significant (more than 50%) pain relief.

CONCLUSION

UVB phototherapy in the acute stage of zoster rash might reduce the incidence and severity of PHN. Treatment after 3 months does not seem to have a significant beneficial effect.