Ultraviolet radiation, both UVA and UVB, influences the composition of the skin microbiome.

BACKGROUND: Studies have begun to investigate the complex relationship between host and microorganisms in non-infectious pathologies such as acne, atopic dermatitis and psoriasis. Though the skin is exposed to environmental stressors such as ultraviolet radiation (UVR), no studies exist examining the effects of both UVA and UVB on the skin microbiome. OBJECTIVE: To test the effect of UVA and UVB on human skin microbiome. METHODS: To test whether UV will alter the cutaneous microbiome, participants were exposed to doses of UVA (22-47 J/cm2 ) or UVB (100-350 mJ/cm2 ) and samples were collected. DNA was isolated and sequenced to identify the microbial composition of each sample. RESULTS: There was vast intra- and inter-subject variation at all time points, and phylum and species-level differences were identified. These included an increase in the phylum Cyanobacteria and a decrease in the family Lactobacillaceae and Pseudomonadaceae. The sensitivity of microbes to UVR and their re-colonization potential following exposure differed in UVA vs UVB samples. LIMITATIONS: The sample size was small, and the study was limited to males. CONCLUSION: The results demonstrate that UVR has profound qualitative and quantitative influences on the composition of the skin microbiome, possibly effecting skin pathology in which UVR is a factor.

Identification of genetic modifiers of age-at-onset for familial Parkinson's disease.

Parkinson's disease (PD) is the most common cause of neurodegenerative movement disorder and the second most common cause of dementia. Genes are thought to have a stronger effect on age-at-onset of PD than on risk, yet there has been a phenomenal success in identifying risk loci but not age-at-onset modifiers. We conducted a genome-wide study for age-at-onset. We analysed familial and non-familial PD separately, per prior evidence for strong genetic effect on age-at-onset in familial PD. GWAS was conducted in 431 unrelated PD individuals with at least one affected relative (familial PD) and 1544 non-familial PD from the NeuroGenetics Research Consortium (NGRC); an additional 737 familial PD and 2363 non-familial PD were used for replication. In familial PD, two signals were detected and replicated robustly: one mapped to LHFPL2 on 5q14.1 (PNGRC = 3E-8, PReplication = 2E-5, PNGRC + Replication = 1E-11), the second mapped to TPM1 on 15q22.2 (PNGRC = 8E-9, PReplication = 2E-4, PNGRC + Replication = 9E-11). The variants that were associated with accelerated onset had low frequencies (<0.02). The LHFPL2 variant was associated with earlier onset by 12.33 [95% CI: 6.2; 18.45] years in NGRC, 8.03 [2.95; 13.11] years in replication, and 9.79 [5.88; 13.70] years in the combined data. The TPM1 variant was associated with earlier onset by 15.30 [8.10; 22.49] years in NGRC, 9.29 [1.79; 16.79] years in replication, and 12.42 [7.23; 17.61] years in the combined data. Neither LHFPL2 nor TPM1 was associated with age-at-onset in non-familial PD. LHFPL2 (function unknown) is overexpressed in brain tumours. TPM1 encodes a highly conserved protein that regulates muscle contraction, and is a tumour-suppressor gene.

Stool Immune Profiles Evince Gastrointestinal Inflammation in Parkinson's Disease.

BACKGROUND: Gastrointestinal symptoms are common in Parkinson's disease and frequently precede the development of motor impairments. Intestinal inflammation has been proposed as a driver of disease pathology, and evaluation of inflammatory mediators in stool could possibly identify valuable early-stage biomarkers. We measured immune- and angiogenesis-related proteins in human stool to examine inflammatory profiles associated with Parkinson's disease. METHODS: Stool samples and subjects' self-reported metadata were obtained from 156 individuals with Parkinson's disease and 110 without, including spouse and nonhousehold controls. Metadata were probed for disease-associated differences, and levels of 37 immune and angiogenesis factors in stool homogenates were measured by multiplexed immunoassay and compared across experimental groups. RESULTS: Parkinson's disease patients reported greater incidence of intestinal disease and digestive problems than controls. Direct comparison of levels of stool analytes in patients and controls revealed elevated vascular endothelial growth factor receptor 1, interleukin-1α, and CXCL8 in patients' stool. Paired comparison of patients and spouses suggested higher levels of multiple factors in patients, but this was complicated by sex differences. Sex, body mass index, a history of smoking, and use of probiotics were found to strongly influence levels of stool analytes. Multivariate analysis accounting for these and other potential confounders confirmed elevated levels of interleukin-1α and CXCL8 and also revealed increased interleukin-1ß and C-reactive protein in stool in Parkinson's disease. These differences were not dependent on subject age or disease duration. CONCLUSIONS: Levels of stool immune factors indicate that intestinal inflammation is present in patients with Parkinson's disease. © 2018 International Parkinson and Movement Disorder Society.

Parkinson's disease and Parkinson's disease medications have distinct signatures of the gut microbiome.

BACKGROUND: There is mounting evidence for a connection between the gut and Parkinson's disease (PD). Dysbiosis of gut microbiota could explain several features of PD. OBJECTIVE: The objective of this study was to determine if PD involves dysbiosis of gut microbiome, disentangle effects of confounders, and identify candidate taxa and functional pathways to guide research. METHODS: A total of 197 PD cases and 130 controls were studied. Microbial composition was determined by 16S rRNA gene sequencing of DNA extracted from stool. Metadata were collected on 39 potential confounders including medications, diet, gastrointestinal symptoms, and demographics. Statistical analyses were conducted while controlling for potential confounders and correcting for multiple testing. We tested differences in the overall microbial composition, taxa abundance, and functional pathways. RESULTS: Independent microbial signatures were detected for PD (P = 4E-5), participants' region of residence within the United States (P = 3E-3), age (P = 0.03), sex (P = 1E-3), and dietary fruits/vegetables (P = 0.01). Among patients, independent signals were detected for catechol-O-methyltransferase-inhibitors (P = 4E-4), anticholinergics (P = 5E-3), and possibly carbidopa/levodopa (P = 0.05). We found significantly altered abundances of the Bifidobacteriaceae, Christensenellaceae, [Tissierellaceae], Lachnospiraceae, Lactobacillaceae, Pasteurellaceae, and Verrucomicrobiaceae families. Functional predictions revealed changes in numerous pathways, including the metabolism of plant-derived compounds and xenobiotics degradation. CONCLUSION: PD is accompanied by dysbiosis of gut microbiome. Results coalesce divergent findings of prior studies, reveal altered abundance of several taxa, nominate functional pathways, and demonstrate independent effects of PD medications on the microbiome. The findings provide new leads and testable hypotheses on the pathophysiology and treatment of PD. © 2017 International Parkinson and Movement Disorder Society.

Association of Parkinson disease with structural and regulatory variants in the HLA region.

Historically, association of disease with the major histocompatibility complex (HLA) genes has been tested with HLA alleles that encode antigen-binding affinity. The association with Parkinson disease (PD), however, was discovered with noncoding SNPs in a genome-wide association study (GWAS). We show here that several HLA-region SNPs that have since been associated with PD form two blocks tagged by rs3129882 (p = 9 × 10(-11)) and by rs9268515 and/or rs2395163 (p = 3 × 10(-11)). We investigated whether these SNP-associations were driven by HLA-alleles at adjacent loci. We imputed class I and class II HLA-alleles for 2000 PD cases and 1986 controls from the NeuroGenetics Research Consortium GWAS and sequenced a subset of 194 cases and 204 controls. We were therefore able to assess accuracy of two imputation algorithms against next-generation-sequencing while taking advantage of the larger imputed data sets for disease study. Additionally, we imputed HLA alleles for 843 cases and 856 controls from another GWAS for replication. PD risk was positively associated with the B(∗)07:02_C(∗)07:02_DRB5(∗)01_DRB1(∗)15:01_DQA1(∗)01:02_DQB1(∗)06:02 haplotype and negatively associated with the C(∗)03:04, DRB1(∗)04:04 and DQA1(∗)03:01 alleles. The risk haplotype and DQA1(∗)03:01 lost significance when conditioned on the SNPs, but C(∗)03:04 (OR = 0.72, p = 8 × 10(-6)) and DRB1(∗)04:04 (OR = 0.65, p = 4 × 10(-5)) remained significant. Similarly, rs3129882 and the closely linked rs9268515 and rs2395163 remained significant irrespective of HLA alleles. rs3129882 and rs2395163 are expression quantitative trait loci (eQTLs) for HLA-DR and HLA-DQ (9 × 10(-5) ≥ PeQTL ≥ 2 × 10(-79)), suggesting that HLA gene expression might influence PD. Our data suggest that PD is associated with both structural and regulatory elements in HLA. Furthermore, our study demonstrates that noncoding SNPs in the HLA region can be associated with disease irrespective of HLA alleles, and that observed associations with HLA alleles can sometimes be secondary to a noncoding variant.

Comprehensive research synopsis and systematic meta-analyses in Parkinson's disease genetics: The PDGene database.

More than 800 published genetic association studies have implicated dozens of potential risk loci in Parkinson's disease (PD). To facilitate the interpretation of these findings, we have created a dedicated online resource, PDGene, that comprehensively collects and meta-analyzes all published studies in the field. A systematic literature screen of -27,000 articles yielded 828 eligible articles from which relevant data were extracted. In addition, individual-level data from three publicly available genome-wide association studies (GWAS) were obtained and subjected to genotype imputation and analysis. Overall, we performed meta-analyses on more than seven million polymorphisms originating either from GWAS datasets and/or from smaller scale PD association studies. Meta-analyses on 147 SNPs were supplemented by unpublished GWAS data from up to 16,452 PD cases and 48,810 controls. Eleven loci showed genome-wide significant (P < 5 × 10(-8)) association with disease risk: BST1, CCDC62/HIP1R, DGKQ/GAK, GBA, LRRK2, MAPT, MCCC1/LAMP3, PARK16, SNCA, STK39, and SYT11/RAB25. In addition, we identified novel evidence for genome-wide significant association with a polymorphism in ITGA8 (rs7077361, OR 0.88, P  =  1.3 × 10(-8)). All meta-analysis results are freely available on a dedicated online database (www.pdgene.org), which is cross-linked with a customized track on the UCSC Genome Browser. Our study provides an exhaustive and up-to-date summary of the status of PD genetics research that can be readily scaled to include the results of future large-scale genetics projects, including next-generation sequencing studies.

Identification of a novel Parkinson's disease locus via stratified genome-wide association study.

BACKGROUND: Parkinson's disease (PD) is complex and heterogeneous. The numerous susceptibility loci that have been identified reaffirm the complexity of PD but do not fully explain it; e.g., it is not known if any given PD susceptibility gene is associated with all PD or a disease subtype. We also suspect that important disease genes may have escaped detection because of this heterogeneity. We used presence/absence of family history to subdivide the cases and performed genome-wide association studies (GWAS) in Sporadic-PD and Familial-PD separately. The aim was to uncover new genes and gain insight into the genetic architecture of PD. RESULTS: Employing GWAS on the NeuroGenetics Research Consortium (NGRC) dataset stratified by family history (1565 Sporadic-PD, 435 Familial-PD, 1986 controls), we identified a novel locus on chromosome 1p21 in Sporadic-PD (PNGRC = 4 × 10(-8)) and replicated the finding (P(Replication) = 6 × 10(-3); P(Pooled) = 4 × 10(-10)) in 1528 Sporadic-PD and 796 controls from the National Institutes of Neurologic Disease and Stroke (NINDS) Repository. This is the fifth PD locus to be mapped to the short arm of chromosome 1. It is flanked by S1PR1 and OLFM3 genes, and is 200 kb from a multiple sclerosis susceptibility gene. The second aim of the study was to extend the stratified GWAS to the well-established PD genes. SNCA_ rs356220 was associated with both Sporadic-PD (OR = 1.37, P = 1 × 10(-9)) and Familial-PD (OR = 1.40, P = 2 × 10(-5)). HLA_rs3129882 was more strongly associated with Sporadic-PD (OR = 1.38, P = 5 × 10(-10)) than Familial-PD (OR = 1.12, P = 0.15). In the MAPT region, virtually every single nucleotide polymorphism (SNP) had a stronger effect-size and lower P-value in Familial-PD (peak P = 8 × 10(-7)) than in Sporadic-PD (peak P = 2 × 10(-5)). CONCLUSIONS: We discovered and replicated a new locus for Sporadic-PD which had escaped detection in un-stratified GWAS. This demonstrates that by stratifying on a key variable the power gained due to diminished heterogeneity can sometimes outweigh the power lost to reduced sample size. We also detected distinct patterns of disease associations for previously established PD susceptibility genes, which gives an insight to the genetic architecture of the disease and could aid in the selection of appropriate study population for future studies.

Genome-wide gene-environment study identifies glutamate receptor gene GRIN2A as a Parkinson's disease modifier gene via interaction with coffee.

Our aim was to identify genes that influence the inverse association of coffee with the risk of developing Parkinson's disease (PD). We used genome-wide genotype data and lifetime caffeinated-coffee-consumption data on 1,458 persons with PD and 931 without PD from the NeuroGenetics Research Consortium (NGRC), and we performed a genome-wide association and interaction study (GWAIS), testing each SNP's main-effect plus its interaction with coffee, adjusting for sex, age, and two principal components. We then stratified subjects as heavy or light coffee-drinkers and performed genome-wide association study (GWAS) in each group. We replicated the most significant SNP. Finally, we imputed the NGRC dataset, increasing genomic coverage to examine the region of interest in detail. The primary analyses (GWAIS, GWAS, Replication) were performed using genotyped data. In GWAIS, the most significant signal came from rs4998386 and the neighboring SNPs in GRIN2A. GRIN2A encodes an NMDA-glutamate-receptor subunit and regulates excitatory neurotransmission in the brain. Achieving P(2df) = 10(-6), GRIN2A surpassed all known PD susceptibility genes in significance in the GWAIS. In stratified GWAS, the GRIN2A signal was present in heavy coffee-drinkers (OR = 0.43; P = 6×10(-7)) but not in light coffee-drinkers. The a priori Replication hypothesis that "Among heavy coffee-drinkers, rs4998386_T carriers have lower PD risk than rs4998386_CC carriers" was confirmed: OR(Replication) = 0.59, P(Replication) = 10(-3); OR(Pooled) = 0.51, P(Pooled) = 7×10(-8). Compared to light coffee-drinkers with rs4998386_CC genotype, heavy coffee-drinkers with rs4998386_CC genotype had 18% lower risk (P = 3×10(-3)), whereas heavy coffee-drinkers with rs4998386_TC genotype had 59% lower risk (P = 6×10(-13)). Imputation revealed a block of SNPs that achieved P(2df)<5×10(-8) in GWAIS, and OR = 0.41, P = 3×10(-8) in heavy coffee-drinkers. This study is proof of concept that inclusion of environmental factors can help identify genes that are missed in GWAS. Both adenosine antagonists (caffeine-like) and glutamate antagonists (GRIN2A-related) are being tested in clinical trials for treatment of PD. GRIN2A may be a useful pharmacogenetic marker for subdividing individuals in clinical trials to determine which medications might work best for which patients.

Preventative topical diclofenac treatment differentially decreases tumor burden in male and female Skh-1 mice in a model of UVB-induced cutaneous squamous cell carcinoma.

Ultraviolet B (UVB) light is the major environmental carcinogen contributing to non-melanoma skin cancer (NMSC) development. There are over 3.5 million NMSC diagnoses in two million patients annually, with men having a 3-fold greater incidence of squamous cell carcinoma (SCC) compared with women. Chronic inflammation has been linked to tumorigenesis, with a key role for the cyclooxygenase-2 (COX-2) enzyme. Diclofenac, a COX-2 inhibitor and non-steroidal anti-inflammatory drug, currently is prescribed to patients as a short-term therapeutic agent to induce SCC precursor lesion regression. However, its efficacy as a preventative agent in patients without evidence of precursor lesions but with significant UVB-induced cutaneous damage has not been explored. We previously demonstrated in a murine model of UVB-induced skin carcinogenesis that when exposed to equivalent UVB doses, male mice had lower levels of inflammation but developed increased tumor multiplicity, burden and grade compared with female mice. Because of the discrepancy in the degree of inflammation between male and female skin, we sought to determine if topical treatment of previously damaged skin with an anti-inflammatory COX-2 inhibitor would decrease tumor burden and if it would be equally effective in the sexes. Our results demonstrated that despite observed sex differences in the inflammatory response, prolonged topical diclofenac treatment of chronically UVB-damaged skin effectively reduced tumor multiplicity in both sexes. Unexpectedly, tumor burden was significantly decreased only in male mice. Our data suggest a new therapeutic use for currently available topical diclofenac as a preventative intervention for patients predisposed to cutaneous SCC development before lesions appear.

Functional regulatory divergence of the innate immune system in interspecific Drosophila hybrids.

In order to investigate divergence of immune regulation among Drosophila species, we have engaged in a study of innate immune function in F1 hybrids of Drosophila melanogaster and D. simulans. If pathways have diverged between the species such that incompatibilities have arisen between interacting components of the immune network, we expect the hybrids to display dysregulation of immune genes. We have quantified gene induction in hybrid and parental flies in response to bacterial infection. These results show that although the hybrids do not suffer widespread immune breakdown, they show significantly different regulation of many immune genes relative to the parents. We examine this divergence in terms of additivity and expression differences among genes, observing distinct patterns of dysregulation among functional groups within the pathways of the innate immune system. The functional groups most sensitive to misexpression in the hybrids are the downstream components of the network, indicative of some propagation of dysregulation throughout the immune pathways. Interestingly, this dysregulation does not appear to associate with phenotypic differences in bacterial load after infection in hybrids, possibly highlighting some robustness of function of the innate immune response to perturbations like hybridization.

Plasticity-related gene 3 (LPPR1) and age at diagnosis of Parkinson disease.

OBJECTIVE: To identify modifiers of age at diagnosis of Parkinson disease (PD). METHODS: Genome-wide association study (GWAS) included 1,950 individuals with PD from the NeuroGenetics Research Consortium (NGRC) study. Replication was conducted in the Parkinson's, Genes and Environment study, including 209 prevalent (PAGEP) and 517 incident (PAGEI) PD cases. Cox regression was used to test association with age at diagnosis. Individuals without neurologic disease were used to rule out confounding. Gene-level analysis and functional annotation were conducted using Functional Mapping and Annotation of GWAS platform (FUMA). RESULTS: The GWAS revealed 2 linked but seemingly independent association signals that mapped to LPPR1 on chromosome 9. LPPR1 was significant in gene-based analysis (p = 1E-8). The top signal (rs17763929, hazard ratio [HR] = 1.88, p = 5E-8) replicated in PAGEP (HR = 1.87, p = 0.01) but not in PAGEI. The second signal (rs73656147) was robust with no evidence of heterogeneity (HR = 1.95, p = 3E-6 in NGRC; HR = 2.14, p = 1E-3 in PAGEP + PAGEI, and HR = 2.00, p = 9E-9 in meta-analysis of NGRC + PAGEP + PAGEI). The associations were with age at diagnosis, not confounded by age in patients or in the general population. The PD-associated regions included variants with Combined Annotation Dependent Depletion (CADD) scores = 10-19 (top 1%-10% most deleterious mutations in the genome), a missense with predicted destabilizing effect on LPPR1, an expression quantitative trait locus (eQTL) for GRIN3A (false discovery rate [FDR] = 4E-4), and variants that overlap with enhancers in LPPR1 and interact with promoters of LPPR1 and 9 other brain-expressed genes (Hi-C FDR < 1E-6). CONCLUSIONS: Through association with age at diagnosis, we uncovered LPPR1 as a modifier gene for PD. LPPR1 expression promotes neuronal regeneration after injury in animal models. Present data provide a strong foundation for mechanistic studies to test LPPR1 as a driver of response to damage and a therapeutic target for enhancing neuroregeneration and slowing disease progression.

Proteomic Analysis and Functional Studies of Baicalin on Proteins Associated with Skin Cancer.

Abundant evidence supports the key role of ultraviolet radiation (UVR) in skin cancer development. The human skin, especially the epidermal layer, is the main defense against UV radiation. Baicalin is a major bioactive component of Scutellaria baicalensis Georgi, a plant which has been found to exhibit antitumor activity. The anticarcinogenic mechanism of baicalin is not completely understood. We have reported that baicalin inhibited UVB-induced photo-damage and apoptosis in HaCaT cells (human skin keratinocytes). The aim of the present study is to investigate the cellular gene targets responsible for baicalin's antitumor activity by performing two-dimensional electrophoresis liquid chromatography-mass spectrometry/mass spectrometry (2-DE LC-MS/MS) with HaCaT cells following UVB and baicalin exposure. Two-DE for protein separation was performed, followed by matrix-assisted laser desorption/ionization mass spectrometry and database searches. Nucleophosmin (NPM)-specific siRNA was designed and synthesized, and the small interfering RNA was transfected into skin squamous cancer A431 cells to knockdown the NPM expression. Proliferation and cell cycle status were assessed by CCK8 and flow cytometric analyses, respectively. We have identified 38 protein spots that are differentially expressed in HaCaT cells exposed to baicalin and/or UVB irradiation These proteins are involved in detoxification, proliferation, metabolism, cytoskeleton and motility. In particular, we found several proteins that have been linked to tumor progression and resistance, such as NPM. Baicalin treatment reduced the cellular proliferation rate and induced arrest during the S-phase of the cell cycle in A431 cells. NPM1 silencing significantly enhanced the effect of baicalin. Our data indicated that baicalin results in the significant inhibition of tumor growth in the A431 cell line, which may be associated with the regulation of the NPM gene expression.

Association of Vitamin D Receptor Polymorphisms With the Risk of Nonmelanoma Skin Cancer in Adults.

IMPORTANCE: Protective effects of UV-B radiation against nonmelanoma skin cancer (NMSC) are exerted via signaling mechanisms involving the vitamin D receptor (VDR). Recent studies have examined single-nucleotide polymorphisms (SNPs) in the VDR, resulting in contradictory findings as to whether these polymorphisms increase a person's risk for NMSC. OBJECTIVE: To examine whether the polymorphisms in the VDR gene are associated with the development of NMSC and the demographic characteristics of the participants. DESIGN, SETTING, AND PARTICIPANTS: This case-control study recruited 100 individuals who received a diagnosis of and were being treated for basal cell carcinoma or squamous cell carcinoma (cases) and 100 individuals who were receiving treatment of a condition other than skin cancer (controls) at the dermatology clinics at the Kirklin Clinic of the University of Alabama at Birmingham Hospital between January 1, 2012, and December 31, 2014. All participants completed a questionnaire that solicited information on skin, hair, and eye color; skin cancer family history; and sun exposure history, such as tanning ability and number of severe sunburns experienced throughout life. Blood samples for DNA genotyping were collected from all participants. MAIN OUTCOMES AND MEASURES: Polymorphisms in the VDR gene (ApaI, BsmI, and TaqI) were assessed to determine the association of polymorphisms with NMSC development and demographic characteristics. χ2 Analysis was used to determine whether genotype frequencies deviated significantly from Hardy-Weinberg equilibrium. Logistic regression was used to calculate odds ratios (ORs) and associated 95% CIs for the identification of factors associated with NMSC diagnosis. A model was created to predict NMSC diagnoses using known risk factors and, potentially, VDR SNPs. RESULTS: A total of 97 cases and 100 controls were included. Of the 97 cases, 68 (70%) were men and 29 (30%) were women, with a mean (SD) age of 70 (11) years. Of the 100 controls, 46 (46%) were men and 54 (54%) were women, with a mean (SD) age of 63 (9) years. All participants self-identified as non-Hispanic white. A model including age, sex, and skin color was created to most effectively predict the incidence of skin cancer. Risk factors that significantly increased the odds of an NMSC diagnosis were light skin color (OR, 5.79 [95% CI, 2.79-11.99]), greater number of severe sunburns (OR, 2.59 [95% CI, 1.31-5.10]), light eye color (OR, 2.47 [95% CI, 1.30-4.67]), and less of an ability to tan (OR, 2.35 [95% CI, 1.23-4.48]). The risk factors of family history of NMSC (OR, 1.66 [95% CI, 0.90-3.07]) and light hair color (OR, 1.17 [95% CI, 0.51-2.71]) did not reach statistical significance. Participants with the BsmI SNP were twice as likely to develop NMSC than participants with no mutation (OR, 2.04 [95% CI, 1.02-4.08]; P = .045). CONCLUSIONS AND RELEVANCE: The results of this study are especially useful in the early treatment and prevention of NMSC with chemopreventive agents (for those with the BsmI SNP). A screening for the BsmI SNP may emphasize the importance of sun protection and facilitate skin cancer prevention and, therefore, decrease the skin cancer burden.

Short Term, Low Dose Simvastatin Pretreatment Alters Memory Immune Function Following Secondary Staphylococcus aureus Infection.

Statins are potent modulators of immune responses, resulting in their ability to enhance host survival from primary bacterial infections. Alterations in primary immune responses that may be beneficial for survival following infection may also result in alterations in the generation of the immunologic memory response and subsequently affect immune responses mounted during secondary bacterial infection. In this study, we report that levels of total serum IgG2c, following primary infection, were decreased in simvastatin pretreated mice, and investigate the effect of simvastatin treatment, prior to primary infection, on immune responses activated during secondary S. aureus infection. A secondary infection model was implemented whereby simvastatin pretreated and control mice were reinfected with S. aureus 14 days after primary infection, with no additional simvastatin treatment, and assessed for survival and alterations in immune function. While survivability to secondary S. aureus infection was not different between simvastatin pretreated and control mice, memory B and T lymphocyte functions were altered. Memory B cells, isolated 14 days after secondary infection, from simvastatin pretreated mice and stimulated ex vivo produced increased levels of IgG1 compared to memory B cells isolated from control mice, while levels of IgM and IgG2c remained similar. Furthermore, memory B and T lymphocytes from simvastatin pretreated mice exhibited a decreased proliferative response when stimulated ex vivo compared to memory cells isolated from control mice. These findings demonstrate the ability of a short term, low dose simvastatin treatment to modulate memory immune function.

Vitamin D and skin cancer.

Vitamin D signaling plays a key role in many important processes, including cellular proliferation, differentiation and apoptosis, immune regulation, hormone secretion and skeletal health. Furthermore, vitamin D production and supplementation have been shown to exert protective effects via an unknown signaling mechanism involving the vitamin D receptor (VDR) in several diseases and cancer types, including skin cancer. With over 3.5 million new diagnoses in 2 million patients annually, skin cancer is the most common cancer type in the United States. While ultraviolet B (UVB) radiation is the main etiologic factor for nonmelanoma skin cancer (NMSC), UVB also induces cutaneous vitamin D production. This paradox has been the subject of contradictory findings in the literature in regards to amount of sun exposure necessary for appropriate vitamin D production, as well as any beneficial or detrimental effects of vitamin D supplementation for disease prevention. Further clinical and epidemiological studies are necessary to elucidate the role of vitamin D in skin carcinogenesis.

Baicalin Protects Keratinocytes from Toll-like Receptor-4 Mediated DNA Damage and Inflammation Following Ultraviolet Irradiation.

UVB radiation contributes to both direct and indirect damage to the skin including the generation of free radicals and reactive oxygen species (ROS), inflammatory responses, immunosuppression and gene mutations, which can ultimately lead to photocarcinogenesis. A plant-derived flavonoid, baicalin, has been shown to have antioxidant, anti-inflammatory and free radical scavenging activities. Previous studies from our laboratory have shown that in murine skin, Toll-like receptor-4 (TLR4) enhanced both UVB-induced DNA damage and inflammation. The aim of this study was to investigate the efficacy of baicalin against TLR4-mediated processes in the murine keratinocyte PAM 212 cell line. Our results demonstrate that treating keratinocytes with baicalin both before and after UV radiation (100 mJ cm(-2) ) significantly inhibited the level of intracellular ROS and decreased cyclobutane pyrimidine dimers and 8-Oxo-2'-deoxyguanosine (8-oxo-dG)-markers of DNA damage. Furthermore, cells treated with baicalin demonstrated an inhibition of TLR4 and its downstream signaling molecules, MyD88, TRIF, TRAF6 and IRAK4. TLR4 pathway inhibition resulted in NF-κB inactivation and down-regulation of iNOS and COX-2 protein expression. Taken together, baicalin treatment effectively protected keratinocytes from UVB-induced inflammatory damage through TLR pathway modulation.

Extended UVB Exposures Alter Tumorigenesis and Treatment Efficacy in a Murine Model of Cutaneous Squamous Cell Carcinoma.

Epidemiological studies support a link between cumulative sun exposure and cutaneous squamous cell carcinoma (SCC) development. However, the presumed effects of extended ultraviolet light B (UVB) exposure on tumorigenesis in the sexes have not been formally investigated. We examined differences in ultimate tumorigenesis at 25 weeks in mice exposed to UVB for either 10 or 25 weeks. Additionally, we investigated the effect of continued UVB exposure on the efficacy of topical treatment with anti-inflammatory (diclofenac) or antioxidant (C E Ferulic or vitamin E) compounds on modulating tumorigenesis. Vehicle-treated mice in the 25-week UVB exposure model exhibited an increased tumor burden and a higher percentage of malignant tumors compared to mice in the 10-week exposure model, which correlated with increases in total and mutant p53-positive epidermal cells. Only topical diclofenac decreased tumor number and burden in both sexes regardless of UVB exposure length. These data support the commonly assumed but not previously demonstrated fact that increased cumulative UVB exposure increases the risk of UVB-induced SCC development and can also affect therapeutic efficacies. Our study suggests that cessation of UVB exposure by at-risk patients may decrease tumor development and that topical NSAIDs such as diclofenac may be chemopreventive.

Differential effects of topical vitamin E and C E Ferulic® treatments on ultraviolet light B-induced cutaneous tumor development in Skh-1 mice.

Because of the ever-increasing incidence of ultraviolet light B (UVB)-induced skin cancer, considerable attention is being paid to prevention through the use of both sunscreens and after sun treatments, many of which contain antioxidants. Vitamin E is included as an antioxidant in many sunscreens and lotions currently on the market. Studies examining the efficacy of vitamin E as a topical preventative agent for UVB-induced skin cancer have yielded conflicting results. A likely contributor to differences in study outcome is the stability of vitamin E in the particular formulation being tested. In the current study we examined the effects of topical vitamin E alone as well as vitamin E combined with vitamin C and ferulic acid in a more stable topical formula (C E Ferulic®). Mice were exposed to UVB for 10 weeks in order to induce skin damage. Then, before the appearance of any cutaneous lesions, mice were treated for 15 weeks with a topical antioxidant, without any further UVB exposure. We found that topical C E Ferulic decreased tumor number and tumor burden and prevented the development of malignant skin tumors in female mice with chronically UVB-damaged skin. In contrast, female mice chronically exposed to UVB and treated topically with vitamin E alone showed a trend towards increased tumor growth rate and exhibited increased levels of overall DNA damage, cutaneous proliferation, and angiogenesis compared to vehicle-treated mice. Thus, we have demonstrated that topical 5% alpha tocopherol may actually promote carcinogenesis when applied on chronically UVB-damaged skin while treating with a more stable antioxidant compound may offer therapeutic benefits.

Short term statin treatment improves survival and differentially regulates macrophage-mediated responses to Staphylococcus aureus.

Staphylococcus aureus is the most prevalent etiologic agent of sepsis. Statins, primarily prescribed for their cholesterol-lowering capabilities, may be beneficial for treating sepsis due to their anti-inflammatory properties. This study examined the effect of low dose, short term simvastatin pretreatment in conjunction with antibiotic treatment on host survival and demonstrated that pretreatment with simvastatin increased survival of C57BL/6 mice in response to S. aureus infection. In vitro studies revealed that short term simvastatin pretreatment did not reduce S. aureus-stimulated expression of surface proteins necessary for macrophage presentation of antigen to T cells, such as MHC Class II and costimulatory molecules CD80 and CD86, but did reduce both basal and S. aureus-stimulated levels of C5aR. Additionally, this work demonstrated the ability of simvastatin to dampen macrophage responses initiated not only by bacteria directly but by membrane vesicles shed in response to infection, revealing a new mechanism of immune modulation by statins. These data demonstrate the ability of short term simvastatin pretreatment to modulate immune responses and identify new insights into the underlying mechanisms of the anti-inflammatory properties of simvastatin that may decrease the pathophysiological effects leading to sepsis.