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Objective This project aims to use our robust women's health patient data to analyze the correlation between cytology and high-risk human papillomavirus (Hr-HPV) testing, study the performance of Hr-HPV testing for detecting cytology lesions, and examine epidemiologic measures of human papillomavirus (HPV) infections in the women's veteran population. Methods We collected patient data from 2014 to 2020 from our computerized patient record system. We performed HPV assays using the cobas® 4800 system (Roche Diagnostics, Basel, Switzerland). The cobas HPV assay detects HPV 16, HPV 18, and 12 other HPV types (31, 33, 35, 39, 45, 51, 56, 58, 59, 66, and 68). We organized cytology results and Hr-HPV assays with Microsoft Access and Microsoft Excel (Microsoft Corporation, Washington, USA) for analysis. Results A total of 9437 cervical specimens were co-tested. High-grade cytology lesions - high-grade intraepithelial lesion (HSIL) or higher and atypical squamous cells, cannot exclude HSIL (ASC-H) - were overwhelmingly positive for Hr-HPV (94.1% and 87.2%, respectively). Low-grade cytology lesions - low-grade squamous intraepithelial lesion ((LSIL) and atypical squamous cells of undetermined significance (ASC-US) - were positive for Hr-HPV in lower percentages (72.6% and 54.9%, respectively). Hr-HPV testing had a sensitivity of 91.3%, a specificity of 93.1%, a positive predictive value of 16.4%, and a negative predictive value of 99.8% for detecting high-grade cytology lesions. Hr-HPV testing had a lower performance for detecting low-grade cytology lesions. Ten cases had high-grade cytology and negative Hr-HPV test. Out of 10 such patients, nine showed no dysplasia (six) or low-grade dysplasia (three) on subsequent biopsy. Overall, 14.4% of tests were positive for Hr-HPV. The highest positive Hr-HPV test rates were in the third and eighth decades of life, 25.1% and 22.0%, respectively. However, the eighth decade consisted of a small sample of only 50 women. In women over 30 years of age with Hr-HPV infections, HPV types 16 and 18 were present in 11.7% and 6.4% of tests, respectively. Other HPV types were present in 82.3% of tests. Conclusions Hr-HPV testing has a high performance in detecting high-grade cytology lesions and a lower performance for detecting low-grade cytology lesions. However, studies show that LSIL rarely progresses to cervical intraepithelial neoplasia grade 3 or higher (CIN3+), suggesting minimal to no impact on cervical cancer screening. We believe our findings are in accordance with recent studies and affirm the guidelines that recommend primary Hr-HPV testing as the preferred screening method. The percentage of positive Hr-HPV tests and rates for age and HPV types 16 and 18 in our women’s veteran population suggest similar HPV prevalence to that of the general US population.

ObjectiveThis project aims to use our robust women’s health patient data to analyze the correlation between cytology and Hr-HPV testing, study performance of Hr-HPV testing for detecting cytology lesions, and examine epidemiologic measures of HPV infections in the women’s veteran population.MethodsWe collected patient data from 2014 to 2020 from our computerized patient record system. We performed HPV assays using the ROCHE 4800 system. The COBAS HPV assay detects HPV 16, HPV 18, and 12 other HPV types (31, 33, 35, 39, 45, 51, 56, 58, 59, 66, and 68). We organized cytology results and Hr-HPV assays with Microsoft Access and Microsoft Excel for analysis.ResultsA total of 9437 cervical specimens were co-tested. High-grade cytology lesions (HSIL or higher and ASC-H) were overwhelmingly positive for Hr-HPV (94.1% and 87.2%, respectively). Low-grade cytology lesions (LSIL and ASC-US) were positive for Hr-HPV in lower percentages (72.6% and 54.9%, respectively). Hr-HPV testing had a sensitivity of 91.3%, a specificity of 93.1%, a positive predictive value of 16.4%, and a negative predictive value of 99.8% for detecting high-grade cytology lesions. Hr-HPV testing had a lower performance for detecting low-grade cytology lesions. Ten (10) cases had high-grade cytology and negative Hr-HPV test. Nine out of ten (9/10) of these patients showed no dysplasia (6) or low-grade dysplasia (3) on subsequent biopsy. Overall, 14.4% of tests were positive for Hr-HPV. The highest positive Hr-HPV test rates were in the second and eighth decades of life, 25.1% and 22.0%, respectively. In women over age 30, HPV types 16 and 18 were present in 11.7% and 6.4% of tests, respectively. Other HPV types were present in 82.3% of tests.ConclusionsHr-HPV testing has high performance for detecting high-grade cytology lesions. We believe our findings are in accordance with recent studies and guidelines that recommend primary Hr-HPV testing as the preferred screening method. The percentage of positive Hr-HPV tests and rates for age and HPV types 16 and 18 in our women’s veteran population suggest similar HPV prevalence to that of the general US population.

Background Coronavirus disease-19 (COVID-19), caused by a novel member of the coronavirus family, is a respiratory disease that rapidly reached pandemic proportions with high morbidity and mortality. In only a few months, it has had a dramatic impact on society and world economies. COVID-19 has presented numerous challenges to all aspects of health care, including reliable methods for diagnosis, treatment, and prevention. Initial efforts to contain the spread of the virus were hampered by the time required to develop reliable diagnostic methods. Artificial intelligence (AI) is a rapidly growing field of computer science with many applications for health care. Machine learning is a subset of AI that uses deep learning with neural network algorithms. It can recognize patterns and achieve complex computational tasks often far quicker and with increased precision than can humans. Methods In this article, we explore the potential for the simple and widely available chest X-ray (CXR) to be used with AI to diagnose COVID-19 reliably. Microsoft CustomVision is an automated image classification and object detection system that is a part of Microsoft Azure Cognitive Services. We utilized publicly available CXR images for patients with COVID-19 pneumonia, pneumonia from other etiologies, and normal CXRs as a dataset to train Microsoft CustomVision. Results Our trained model overall demonstrated 92.9% sensitivity (recall) and positive predictive value (precision), with results for each label showing sensitivity and positive predictive value at 94.8% and 98.9% for COVID-19 pneumonia, 89% and 91.8% for non-COVID-19 pneumonia, 95% and 88.8% for normal lung. We then validated the program using CXRs of patients from our institution with confirmed COVID-19 diagnoses along with non-COVID-19 pneumonia and normal CXRs. Our model performed with 100% sensitivity, 95% specificity, 97% accuracy, 91% positive predictive value, and 100% negative predictive value. Conclusions We have used a readily available, commercial platform to demonstrate the potential of AI to assist in the successful diagnosis of COVID-19 pneumonia on CXR images. The findings have implications for screening and triage, initial diagnosis, monitoring disease progression, and identifying patients at increased risk of morbidity and mortality. Based on the data, a website was created to demonstrate how such technologies could be shared and distributed to others to combat entities such as COVID-19 moving forward.

Introduction/Objective Prostate cancer is the most common non-cutaneous malignancy in veterans, with approximately 11,000 new prostate cancer cases diagnosed in the Veteran’s Affairs system each year. Prostate cancer diagnosis and grading can be challenging even for experienced pathologists. Although large VA medical centers have pathologists that specialize in urologic pathology, the vast majority have not. We hypothesized that the AI-augmented diagnosis and grading may provide the solution for such situations. Methods/Case Report Dataset consisted of 10,000 prostate biopsy whole slide images (WSI) from the Kaggle PANDA challenge, and 6,000 WSI from the James A. Haley Veterans’ Hospital. Two Classification models were trained on the combined Kaggle and VA datasets using whole slide labels, and not annotated slides that resemble semi-supervised training. Two-Class Classification to predict Benign: ISUP [0] / Cancerous: ISUP [1,2,3,4,5] Three-Class Classification to predict Benign: ISUP [0] / Low-grade: ISUP [1,2] / High-grade: ISUP [3,4,5] WSI split into “tiles” were used for training the models to reduce whitespace around samples, manage large images, and normalize dimensions/orientations. Results (if a Case Study enter NA) Models trained purely as binary and 3-class classifiers performed very well. Two-Class Model: Accuracy = 0.937 Precision = 0.965 F1 = 0.94 AUC = 0.979 Three-Class Model: Accuracy 0.89 o Benign: Precision=0.897 f1=0.928 o Low-grade: Precision=0.866 f1=0.841 o High-grade: Precision=0.91 f1=0.878 We plan to develop multi-stage prediction models using these 2-Class and 3-Class classifiers as the first stage and a cancer grade predictor in the second stage. Conclusion We successfully showed that AI can augment pathologist’s diagnosis and grading of prostate cancer.

Two machine learning platforms were successfully used to provide diagnostic guidance in the differentiation between common cancer conditions in veteran populations.

UV damage to the skin leads to the release of noncoding RNA (ncRNA) from necrotic keratinocytes that activates Toll-like receptor 3 (TLR3). This release of ncRNA triggers inflammation in the skin following UV damage. Recently, TLR3 activation was also shown to aid wound repair and increase the expression of genes associated with permeability barrier repair. Here, we sought to test whether skin barrier repair after UVB damage is dependent on the activation of TLR3. We observed that multiple ncRNAs induced expression of skin barrier repair genes, that the TLR3 ligand Poly (I:C) also induced expression and function of tight junctions, and that the ncRNA U1 acts in a TLR3-dependent manner to induce expression of skin barrier repair genes. These observations were shown to have functional relevance as Tlr3-/- mice displayed a delay in skin barrier repair following UVB damage. Combined, these data further validate the conclusion that recognition of endogenous RNA by TLR3 is an important step in the program of skin barrier repair.

Warfarin pharmacogenomic testing has become a prime example of the utility of personalized molecular testing in the modern clinical laboratory. Warfarin is a commonly used drug for the prevention and treatment of thromboembolic complications in a variety of clinical situations. However, a number of factors lead to a high interindividual variability in dose requirements. Among the primary factors in this variability are genetic polymorphisms in general patient populations, which can account for 35-50% of varying dose requirements among patients. In this review, we discuss the implications of polymorphisms in the cytochrome P-450 enzyme 2C9 (CYP2C9) and Vitamin K Epoxide Reductase Enzyme Complex subunit 1 (VKORC1) as they relate to therapeutic warfarin dosing. We discuss the clinical utility of pharmacogenomics testing as related to warfarin dosing, and propose a clinical model for the implementation of the pharmacogenomic test results. Finally, we provide a brief overview of the currently available commercial testing platforms with discussion of the complexities of utilizing patented methodologies in bringing genetic testing such as this to the clinical laboratory.

In this study, we observed that mice lacking the IL-1 receptor (IL-1R) ( IL1r –/– ) or deficient in IL1-β developed multiple epidermal cysts after chronic UVB exposure. Cysts that developed in IL1r –/– mice were characterized by the presence of the hair follicle marker Sox 9, keratins 10 and 14, and normal melanocyte distribution and retinoid X receptor-α expression. The increased incidence of cysts in IL1r –/– mice was associated with less skin inflammation as characterized by decreased recruitment of macrophages, and their skin also maintained epidermal barrier function compared with wild-type mice. Transcriptional analysis of the skin of IL1r –/– mice after UVB exposure showed decreased gene expression of proinflammatory cytokines such as tumor necrosis factor-α and IL-6. In vitro, primary keratinocytes derived from IL1r –/– mice were more resistant to UVB-triggered cell death compared with wild-type cells, and tumor necrosis factor-α release was completely blocked in the absence of IL-1R. These observations illustrate an unexpected yet prominent phenotype associated with the lack of IL-1R signaling in mice and support further investigation into the role of IL-1 ligands in epidermal repair and innate immune response after damaging UVB exposure.

A critical function for skin is that when damaged it must simultaneously identify the nature of the injury, repair barrier function, and limit the intrusion of pathogenic organisms. These needs are carried out through the detection of damage-associated molecular patterns (DAMPs) and a response that includes secretion of cytokines, chemokines, growth factors, and antimicrobial peptides (AMPs). In this study, we analyzed how non-coding double-stranded RNA (dsRNAs) act as a DAMP in the skin and how the human cathelicidin AMP LL-37 might influence growth factor production in response to this DAMP. dsRNA alone significantly increased the expression of multiple growth factors in keratinocytes, endothelial cells, and fibroblasts. Furthermore, RNA sequencing transcriptome analysis found that multiple growth factors increase when cells are exposed to both LL-37 and dsRNA, a condition that mimics normal wounding. Quantitative PCR and/or ELISA validated that growth factors expressed by keratinocytes in these conditions included, but were not limited to, basic fibroblast growth factor (FGF2), heparin-binding EGF-like growth factor (HBEGF), vascular endothelial growth factor C (VEGFC), betacellulin (BTC), EGF, epiregulin (EREG), and other members of the transforming growth factor β superfamily. These results identify a novel role for DAMPs and AMPs in the stimulation of repair and highlight the complex interactions involved in the wound environment.

Exposure to ultraviolet B (UVB) radiation from the sun can result in sunburn, premature aging and carcinogenesis, but the mechanism responsible for acute inflammation of the skin is not well understood. Here we show that RNA is released from keratinocytes after UVB exposure and that this stimulates production of the inflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) from nonirradiated keratinocytes and peripheral blood mononuclear cells (PBMCs). Whole-transcriptome sequencing revealed that UVB irradiation of keratinocytes induced alterations in the double-stranded domains of some noncoding RNAs. We found that this UVB-damaged RNA was sufficient to induce cytokine production from nonirradiated cells, as UVB irradiation of a purified noncoding RNA (U1 RNA) reproduced the same response as the one we observed to UVB-damaged keratinocytes. The responses to both UVB-damaged self-RNAs and UVB-damaged keratinocytes were dependent on Toll-like receptor 3 (TLR3) and Toll-like receptor adaptor molecule 1 (TRIF). In response to UVB exposure, Tlr3(-/-) mice did not upregulate TNF-α in the skin. Moreover, TLR3 was also necessary for UVB-radiation-induced immune suppression. These findings establish that UVB damage is detected by TLR3 and that self-RNA is a damage-associated molecular pattern that serves as an endogenous signal of solar injury.

A diverse environment challenges skin to maintain temperature, hydration, and electrolyte balance while also maintaining normal immunological function. Rosacea is a common skin disease that manifests unique inflammatory responses to normal environmental stimuli. We hypothesized that abnormal function of innate immune pattern recognition could explain the enhanced sensitivity of patients with rosacea, and observed that the epidermis of patients with rosacea expressed higher amounts of Toll-like receptor 2 (TLR2) than normal patients. Increased expression of TLR2 was not seen in other inflammatory skin disorders such as atopic dermatitis or psoriasis. Overexpression of TLR2 on keratinocytes, treatment with TLR2 ligands, and analysis of TLR2-deficient mice resulted in a calcium-dependent release of kallikrein 5 from keratinocytes, a critical protease involved in the pathogenesis of rosacea. These observations show that abnormal TLR2 function may explain enhanced inflammatory responses to environmental stimuli and can act as a critical element in the pathogenesis of rosacea.

Introduction: Graft-versus-host disease (GvHD) is a severe complication arising in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Potent and selective modulation of JAK/STAT-mediated signaling is an attractive therapeutic strategy for the management of acute GvHD and is currently being evaluated in clinical trials (REACH1: NCT02953678; REACH2: NCT02913261). Methods: Acute GvHD was induced in BALB/c mice using the established MHC-mismatched mouse model. BALB/c (H-2Kd) recipients were given an intravenous injection of a combination of splenocytes and T cell depleted bone marrow cells received from allogeneic cell transfer from donor C57BL/6 (H-2Kb) mice. Animals were dosed orally with vehicle or the potent and selective JAK1/JAK2 inhibitor, ruxolitinib (60 mg/kg) twice daily. Engraftment was analyzed for the proportion of donor and host leukocytes (CD45, H-2Kb, and H-2Kd). GvHD clinical scores were assessed by standard methods and inflammatory cytokine profiles in blood and colon quantified by multiplex analyses. Colon samples were sectioned at approximately 5 microns, and stained with the following immunohistochemical (IHC) markers: CD4, CD8, phosphoSTAT3/STAT5, CD3+phosphoSTAT3/STAT5 (dual staining) for pharmacodynamic assessment of JAK/STAT pathway activity in colon and infiltrating T-cells. Effects of ruxolitinib in corticosteroid refractory mice were evaluated by treating disease bearing BALB/c mice twice daily with an optimal oral dose of prednisolone (1 mg/kg) until the GvHD scores were comparable to vehicle treated mice. Steroid resistant animals were switched to ruxolitinib to determine the potential efficacy benefit in comparison to mice maintained on ruxolitinib treatment alone for the duration of the study. Results: Oral ruxolitinib administration was highly effective in both prophylactic (from day −3) and therapeutic (from day 14) dosing regimens in ameliorating body weight loss, improving GvHD scores and had no detrimental effects on donor engraftment. Comparable efficacy was observed between prophylactic and therapeutic treatment with 60 mg/kg twice daily dosing regimens. Oral ruxolitinib administration in BALB/c mice achieved JAK1/JAK2 IC50 coverage for 8 h with 60 mg/kg twice daily. Associated with GvHD progression, maximal upregulation of inflammatory cytokines were observed in peripheral blood on day 17 (IFN-γ, TNF-α, IL-6, IL-13) and in colon on day 28 (IFN-γ, TNF-α, IL-1β). Ruxolitinib (60 mg/kg twice daily) treatment significantly reduced the inflammatory cytokine milieu at these disease stages. No differences were observed in absolute number of CD4+ T cells and CD8+ T cells in blood and spleen in groups treated with ruxolitinib, but significant reductions were detected in CD4+ T cells and CD8+ T cells in the inflamed colon tissue along with JAK/STAT pathway inhibition as measured by significant reductions in normalized phosphoSTAT3/STAT5 in T cells and colonic epithelial cells. Prednisolone was transiently effective until day 31 in reducing GvHD scores. Switching treatment regimens from prednisolone to ruxolitinib twice daily rapidly and significantly enhanced GvHD efficacy to a level comparable to ruxolitinib monotherapy. In a dose cessation and resumption paradigm, ruxolitinib restored efficacy when treatment was resumed on day 33 after being halted on day 24. In addition, ruxolitinib significantly enhanced the survival of the recipient BALB/c mice in comparison to vehicle treated animals. Conclusions: Ruxolitinib, a JAK1/JAK2 selective inhibitor, significantly ameliorated GvHD severity with no detrimental effects on engraftment in both a steroid untreated and a corticosteroid refractory MHC-mismatched model of acute GvHD. Efficacy was associated with JAK/STAT pathway inhibition in colon and target tissue infiltrating T-cells. In a dose cessation and resumption paradigm, ruxolitinib restored efficacy once treatment was resumed. In addition, ruxolitinib reduced disease burden and enhanced survival by modulating levels of inflammatory cytokines important in the pathophysiology of acute GvHD. Disclosures Juvekar: Incyte Corporation: Employment. Ruggeri:Incyte Corporation: Employment. Condon:Incyte Corporation: Employment. Borkowski:Biomodels LLC: Employment. Huber:Incyte Corporation: Employment. Smith:Incyte Corporation: Employment.

Introduction: Graft-versus-host disease (GvHD) is a severe complication arising in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Potent and selective modulation of JAK1/STAT-mediated signaling is an attractive therapeutic strategy for the management of acute GvHD and is currently being evaluated in clinical trials (GRAVITAS-301: NCT03139604; GRAVITAS-119: NCT03320642). Methods: Acute GvHD was induced in BALB/c mice using the established MHC-mismatched mouse model. BALB/c (H-2Kd) recipients were given an intravenous injection of a combination of splenocytes and T cell depleted bone marrow cells from allogeneic cell transfer from donor C57BL/6 (H-2Kb) mice. Animals were dosed orally with vehicle or the selective JAK1 inhibitor, itacitinib (60 mg/kg or 120 mg/kg twice daily). Engraftment was analyzed for the proportion of donor and host leukocytes (CD45+, H-2Kb, and H-2Kd). GvHD clinical scores were assessed by standard methods and inflammatory cytokine profiles in blood and colon quantified by multiplex analysis. Colon samples were sectioned and stained with the following immunohistochemical (IHC) markers: CD4, CD8, phosphoSTAT3 and CD3+phosphoSTAT3 (dual staining) for pharmacodynamic assessment of JAK/STAT pathway activity in colon and infiltrating T-cells. Effects of itacitinib on preservation of Graft-versus-Leukemia (GVL) were evaluated by injecting BALB/c mice with A20 lymphoma cells that are of H-2Kd phenotype along with combination of splenocytes and T cell depleted bone marrow from C57BL/6 (H-2Kb) mice. Results: Itacitinib administration was highly effective in both prophylactic (from day −3) and therapeutic (from day 14) dosing regimens in ameliorating body weight loss and improving GvHD scores. Itacitinib did not significantly impact donor engraftment as determined by CD45+/H-2Kb quantification by flow cytometry. Similar efficacy was observed with 60 mg/kg versus 120 mg/kg twice daily dosing regimens. Oral itacitinib administration achieved JAK1 IC50 coverage for 4 h and 12 h at 60 mg/kg twice daily and 120 mg/kg twice daily, respectively. Associated with GvHD progression, maximal upregulation of inflammatory cytokines were observed in peripheral blood on day 17 (IFN-γ, TNF-α, IL-6, IL-13) and in colon on day 28 (IFN-γ, TNF-α, IL-1β). Itacitinib (120 mg/kg twice daily) treatment significantly reduced the inflammatory cytokine milieu at these disease stages. No differences were observed in absolute number of CD4+ T cells and CD8+ T cells in blood and spleen with itacitinib treatment, but significant reductions were detected in CD4+ T cells and CD8+ T cells in the inflamed colon tissue along with significant JAK1/STAT3 inhibition as measured by reductions in normalized pSTAT3 in T cells and colonic epithelial cells. Itacitinib treatment did not negatively impact GVL responses, as evidence by T cell mediated reduction of tumor burden. Furthermore, itacitinib treatment enhanced the survival of the recipient BALB/c mice in comparison to the vehicle treated animals. Conclusions: Itacitinib, a selective JAK1 inhibitor ameliorated GvHD severity when administered prophylactically or therapeutically and had no detrimental effects on engraftment and preservation of GVL. Furthermore, itacitinib inhibited JAK1/STAT3 activation in diseased colon tissue and infiltrating T-cells, and reduced disease burden and improved survival by modulating levels of inflammatory cytokines important in the pathophysiology of acute GvHD. Disclosures Juvekar: Incyte Corporation: Employment. Ruggeri:Incyte Corporation: Employment. Condon:Incyte Corporation: Employment. Borkowski:Biomodels LLC: Employment. Huber:Incyte Corporation: Employment. Smith:Incyte Corporation: Employment.

Summary A crucial tenet of the prion hypothesis is that misfolding of the prion protein (PrP) induced by mutations associated with familial prion disease is, in an otherwise normal mammalian brain, sufficient to generate the infectious agent. Yet this has never been demonstrated. We engineered knockin mice to express a PrP mutation associated with a distinct human prion disease, fatal familial insomnia (FFI). An additional substitution created a strong transmission barrier against pre-existing prions. The mice spontaneously developed a disease distinct from that of other mouse prion models and highly reminiscent of FFI. Unique pathology was transmitted from FFI mice to mice expressing wild-type PrP sharing the same transmission barrier. FFI mice were highly resistant to infection by pre-existing prions, confirming infectivity did not arise from contaminating agents. Thus, a single amino acid change in PrP is sufficient to induce a distinct neurodegenerative disease and the spontaneous generation of prion infectivity.

The human skin is an organ with a surface area of 1.5-2 m(2) that provides our interface with the environment. The molecular composition of this organ is derived from host cells, microbiota, and external molecules. The chemical makeup of the skin surface is largely undefined. Here we advance the technologies needed to explore the topographical distribution of skin molecules, using 3D mapping of mass spectrometry data and microbial 16S rRNA amplicon sequences. Our 3D maps reveal that the molecular composition of skin has diverse distributions and that the composition is defined not only by skin cells and microbes but also by our daily routines, including the application of hygiene products. The technological development of these maps lays a foundation for studying the spatial relationships of human skin with hygiene, the microbiota, and environment, with potential for developing predictive models of skin phenotypes tailored to individual health.

BACKGROUND This study investigated the effects of finasteride, a 5α-reductase inhibitor, clinically used for the treatment of benign prostatic hyperplasia (BPH) on prostate tumor vascularity, apoptosis, and cell adhesion in situ and in vitro. METHODS Prostate specimens from BPH patients treated with finasteride for 1–12 months (n = 13), or without finasteride treatment (n = 14), were evaluated for apoptosis (TUNEL assay), microvessel density (Factor VIII), and prostate specific antigen (PSA) immunoreactivity. In vitro, the effect of finasteride was investigated in benign prostate cells, BPH-1, and its tumorigenic derivatives, CAFTD-01 and CAFTD-03, using Hoechst staining and cell adhesion assays. RESULTS A significant increase in the apoptotic index, and reduced microvessel density and PSA expression were detected in prostates from finasteride-treated patients, compared to controls (P

Granulomatous prostatitis is characterized by a pattern of granulomatous inflammation in the prostate. In most cases the etiology is unknown. Based on the hypothesis that granulomatous prostatitis may be an autoimmune disease we performed intermediate and selective high resolution typing of HLA-DR in a group of patients with the disease and compared the frequency of class II HLA phenotypes to that in a control group of volunteer marrow donors in the military.Histological records from 1 institution from 1990 to 2000 revealed 12 patients with diffuse granulomatous prostatitis. Three patients were dead and 1 refused blood drawing. Peripheral blood from the remaining 8 patients was typed along with blood from an additional 3 identified at the practice of one of us from 1999 through 2002. All slides were reviewed by 1 pathologist. Intermediate resolution typing of HLA-A, B and DR was performed by polymerase chain reaction-sequence specific oligonucleotide probe. High resolution, allele specific identification of HLA DR15 was performed if patients were DR15 positive by intermediate resolution typing.There were 3 black and 8 white individuals identified with diffuse nonspecific granulomatous prostatitis. Six of 8 white patients (75%) were HLA-DR15 by intermediate resolution typing. One of the 3 black American patients (33%) was HLA-DR15. In the control group 127 of 451 white (28.2%) and 23 of 89 black (25.8%) volunteer marrow donors were HLA-DR15. The case-control comparison of white patients was significantly different (Fisher's exact test p = 0.0086). There were no statistically significant differences between case-control comparisons for any other HLA-DR phenotype. High resolution DR15 typing showed that the white patients were HLA-DRB1*1501 and the black patient was HLA-DRB1*1503.The data suggest an association between HLA-DRB1*1501 and granulomatous prostatitis. HLA-DR15 is strongly associated with other autoimmune diseases, notably multiple sclerosis. The data are consistent with an autoimmune etiology for nonspecific granulomatous prostatitis.

Protection of the skin against microbiological infection is provided by the permeability barrier and by antimicrobial proteins. We asked whether the expression of murine β-defensins (mBDs)-1, -3, and -14-orthologs of human β-defensins hBD-1, -2, and -3, respectively--is stimulated by mechanically/physicochemically (tape stripping or acetone treatment) or metabolically (essential fatty acid-deficient (EFAD) diet) induced skin barrier dysfunction. Both methods led to a moderate induction of mBD-1 and mBD-14 and a pronounced induction of mBD-3 mRNA. Protein expression of the mBDs was increased as shown by immunohistology and by western blotting. Artificial barrier repair by occlusion significantly reduced the increased expression of mBD-14 after mechanical injury and of all three mBDs in EFAD mice, supporting an interrelationship between permeability and the antimicrobial barrier. mBD-3 expression was stimulated in vitro by tumor necrosis factor-α (TNF-α), and a neutralizing anti-TNF-α antibody significantly reduced increased mBD-3 expression after barrier injury in mouse skin, indicating that induction of mBD-3 expression is mediated by cytokines. The expression of mBD-14 was stimulated by transforming growth factor-α and not by TNF-α. In summary, we demonstrated upregulation of mBD1, -3, and -14 after mechanically and metabolically induced skin barrier disruption, which may be an attempt to increase defense in the case of permeability barrier dysfunction.

UV radiation poses a significant risk to human health. The mechanisms that help repair UV-damaged cells have recently been more clearly defined with the observation that Toll-like receptor 3 can sense self RNA released from necrotic keratinocytes following UV damage. TLR3 activation in the skin induces inflammation and increases the expression of genes involved in skin barrier repair. Activation of TLR2 in the skin by commensal microbial products prevents excessive inflammation by blocking downstream TLR3 signaling. This review highlights how UV damage–induced inflammation in the skin is propagated by host products and regulated by host inhabitants.

Prion diseases induce neurodegeneration in specific brain areas for undetermined reasons. A thorough understanding of the localization of the disease-causing molecule, the prion protein (PrP), could inform on this issue but previous studies have generated conflicting conclusions. One of the more intriguing disagreements is whether PrP is synthesized by astrocytes. We developed a knock-in reporter mouse line in which the coding sequence of the PrP expressing gene (Prnp), was replaced with that for green fluorescent protein (GFP). Native GFP fluorescence intensity varied between and within brain regions. GFP was present in astrocytes but did not increase during reactive gliosis induced by scrapie prion infection. Therefore, reactive gliosis associated with prion diseases does not cause an acceleration of local PrP production. In addition to aiding in Prnp gene activity studies, this reporter mouse line will likely prove useful for analysis of chimeric animals produced by stem cell and tissue transplantation experiments.

Background Medical treatment of benign prostatic hyperplasia (BPH) targets relief of symptoms by causing either relaxation of the prostatic smooth muscle with α1 adrenergic blockade, or shrinkage of the gland with 5α-reductase inhibitors. We recently demonstrated that α1-blockers, such as terazosin, induce apoptosis in prostatic cells. In this study, we examined the combined effect of finasteride and terazosin on the rate of apoptosis and cellular proliferation to investigate their potential synergy at the cellular level. Methods Prostate specimens were obtained from men who were treated with either finasteride (n = 24), terazosin (n = 42), or combination therapy (n = 10) for varying time periods (1 week to 36 months) for the relief of the symptoms of BPH. The proliferative and apoptotic indices of both stromal and epithelial prostatic cell populations were determined. Antibodies against TGF-β1 and TβRII were used to examine the immunoreactivity of TGF-β1 and TβRII, respectively, in all prostate tissue sections. Results The apoptotic index in both prostate cell populations was significantly higher following the combination treatment compared to terazosin or finasteride alone. There were no significant changes in the rate of cellular proliferation with any treatment. Furthermore, there was a significant increase in TGF-β1 expression in the prostates of patients treated with terazosin or combination therapy, while there was no change in TβRII expression. Conclusions These results support the concept that induction of prostate apoptosis is a potential molecular mechanism underlying the combination effect of α1 blockade with 5α-reductase inhibitors in the effective treatment of BPH. The upregulation of TGF-β1 implies a role for this ligand as an effector of apoptosis induction in response to α1-blockade or finasteride therapy of BPH patients. Prostate 46:45–51, 2001. © 2001 Wiley-Liss, Inc.

BACKGROUND Epidemiologic evidence reveals striking racial differences in incidence and clinical behavior of prostate cancer among American men. In this study, we assessed the incidence of apoptosis and cell proliferation in prostate cancer specimens from African-American and Caucasian patients in an attempt to identify potential differences in tumor growth determinants between the two ethnic groups. METHODS Apoptosis and cell proliferation were analyzed in archival paraffin-embedded prostatic tumors from 44 African-American and 35 Caucasian age-matched men who underwent radical prostatectomy for localized prostate cancer. Both groups had comparable preoperative prostate-specific antigen (PSA) levels, clinical stage, and Gleason scores, and neither group of patients received neoadjuvant therapy prior to surgery. Apoptotic status in prostate tumors was evaluated in situ, using the transferase deoxyuridine end labeling (TUNEL) assay, and the expression profile of two apoptotic proteins, bcl-2 and bax. The proliferative index was determined on the basis of Ki-67 antigen immunoreactivity. RESULTS Apoptosis in malignant prostate cells was significantly higher in African American than Caucasian men (11.6% vs. 4.2%, P < 0.001). Interestingly, the rate of cell proliferation of prostate tumor cells was similar in the two ethnic groups (4.5% and 4.2%). The antiapoptotic protein bcl-2 was detected at significantly higher levels in tumors from Caucasian than African-American patients (40.8% vs. 31.6%, P < 0.05). Expression of bax, the apoptosis promoter, was consistently high among tumor epithelial cells in specimens from both racial groups (68%). CONCLUSIONS These findings provide a novel insight into the molecular determinants of tumor growth that may underlie the ethnic differences in prostate cancer incidence and clinical behavior. Downregulation of bcl-2 expression may be potentially responsible for the loss of apoptotic control in prostate tumors from African-American men. This study may have significant clinical implications in the development of novel diagnostic approaches for biologically aggressive prostate cancer from diverse racial origin. Prostate 42:130–136, 2000. © 2000 Wiley-Liss, Inc.

Markers predictive of therapeutic response of prostatic tumors to radiotherapy may have major significance in optimizing effective treatment of prostate cancer. Because inherent cellular radioresistance plays a critical role in the failure of radiotherapy, in this study, we investigated whether there is a correlation between the ratio of two apoptosis regulators, bcl-2 (apoptosis suppressor) and bax (apoptosis inducer) in prostatic tumors and the clinical response to radiotherapy in patients with localized prostate cancer.A retrospective review of records of 41 patients who underwent external beam radiotherapy for prostate cancer was conducted. On the basis of post-treatment prostate biopsy and prostate-specific antigen (PSA) criteria, the cancers of 20 patients were classified as radiation nonresponders and 21 as radiation responders. Immunohistochemical analysis was performed on paraffin-embedded prostate sections to determine the level of expression of the two apoptotic proteins, bcl-2 and bax, in tumor cells.bcl-2 immunoreactivity was significantly higher in prostatic tumors not responsive to radiotherapy (38.6+/-4.1), compared with the radiation responders (24.1+/-4.6) (P0.001). Expression of bax protein was lower in nonresponders, but values were not significantly different from the responders. The resulting significantly higher bcl-2/bax ratio (P0.01) correlated with poor therapeutic responsiveness of prostate cancer to radiotherapy (1.12+/-0.12 and 0.56+/-0.13, for nonresponders and responders, respectively). This correlation (r=0.67) was independent of age, PSA, and Gleason score.These findings suggest that patients with an elevated bcl-2/bax ratio are at increased risk of their cancer failing to respond to radiotherapy. This study suggests a predictive value for the bcl-2/bax ratio as a potential molecular marker for predicting radioresistance of prostatic tumors.

In man, mutations in different regions of the prion protein (PrP) are associated with infectious neurodegenerative diseases that have remarkably different clinical signs and neuropathological lesions. To explore the roots of this phenomenon, we created a knock-in mouse model carrying the mutation associated with one of these diseases [Creutzfeldt–Jakob disease (CJD)] that was exactly analogous to a previous knock-in model of a different prion disease [fatal familial insomnia (FFI)]. Together with the WT parent, this created an allelic series of three lines, each expressing the same protein with a single amino acid difference, and with all native regulatory elements intact. The previously described FFI mice develop neuronal loss and intense reactive gliosis in the thalamus, as seen in humans with FFI. In contrast, CJD mice had the hallmark features of CJD, spongiosis and proteinase K-resistant PrP aggregates, initially developing in the hippocampus and cerebellum but absent from the thalamus. A molecular transmission barrier protected the mice from any infectious prion agents that might have been present in our mouse facility and allowed us to conclude that the diseases occurred spontaneously. Importantly, both models created agents that caused a transmissible neurodegenerative disease in WT mice. We conclude that single codon differences in a single gene in an otherwise normal genome can cause remarkably different neurodegenerative diseases and are sufficient to create distinct protein-based infectious elements.

Staphylococcus aureus infections present an enormous global health concern complicated by an alarming increase in antibiotic resistance. S. aureus is among the few bacterial species that express nitric-oxide synthase (bNOS) and thus can catalyze NO production from l-arginine. Here we generate an isogenic bNOS-deficient mutant in the epidemic community-acquired methicillin-resistant S. aureus (MRSA) USA300 clone to study its contribution to virulence and antibiotic susceptibility. Loss of bNOS increased MRSA susceptibility to reactive oxygen species and host cathelicidin antimicrobial peptides, which correlated with increased MRSA killing by human neutrophils and within neutrophil extracellular traps. bNOS also promoted resistance to the pharmaceutical antibiotics that act on the cell envelope such as vancomycin and daptomycin. Surprisingly, bNOS-deficient strains gained resistance to aminoglycosides, suggesting that the role of bNOS in antibiotic susceptibility is more complex than previously observed in Bacillus species. Finally, the MRSA bNOS mutant showed reduced virulence with decreased survival and smaller abscess generation in a mouse subcutaneous infection model. Together, these data indicate that bNOS contributes to MRSA innate immune and antibiotic resistance phenotypes. Future development of specific bNOS inhibitors could be an attractive option to simultaneously reduce MRSA pathology and enhance its susceptibility to commonly used antibiotics.

A variety of external perturbations can induce endoplasmic reticulum (ER) stress, followed by stimulation of epithelial cells to produce an innate immune element, the cathelicidin antimicrobial peptide (CAMP). ER stress also increases production of the proapoptotic lipid ceramide and its antiapoptotic metabolite, sphingosine-1-phosphate (S1P). We demonstrate here that S1P mediates ER stress-induced CAMP generation. Cellular ceramide and S1P levels rose in parallel with CAMP levels following addition of either exogenous cell-permeating ceramide (C2Cer), which increases S1P production, or thapsigargin (an ER stressor), applied to cultured human skin keratinocytes or topically to mouse skin. Knockdown of S1P lyase, which catabolizes S1P, enhanced ER stress-induced CAMP production in cultured cells and mouse skin. These and additional inhibitor studies show that S1P is responsible for ER stress-induced upregulation of CAMP expression. Increased CAMP expression is likely mediated via S1P-dependent NF-κB-C/EBPα activation. Finally, lysates of both ER-stressed and S1P-stimulated cells blocked growth of virulent Staphylococcus aureus in vitro, and topical C2Cer and LL-37 inhibited invasion of Staphylococcus aureus into murine skin. These studies suggest that S1P generation resulting in increased CAMP production comprises a novel regulatory mechanism of epithelial innate immune responses to external perturbations, pointing to a new therapeutic approach to enhance antimicrobial defense.

Wound healing is a multifaceted process that depends on both epithelial and bone marrow derived cells to promote proper healing. Recent publications have shown that a subset of T cells in the skin are activated by certain lipids bound to CD1 molecules. Cd1d, the isoform of CD1 expressed in mice, is an MHC-like molecule that binds lipid antigens and is expressed by Langerhans cells (LCs), macrophages, B cells, and wounded keratinocytes. As our lab has previously shown that T cell activation in the skin promotes wound healing, we hypothesize that Cd1d is an important component of normal wound healing. To investigate this hypothesis, we administered full thickness wounds to the dorsal skin of WT and Cd1d−/− mice and analyzed wound closure. Cd1d−/− mice had a significant delay in wound healing between days 1 and 5 compared to WT controls. Analysis of ex vivo wound healing failed to show any difference in wound closure rates between WT and Cd1d−/− skin. This suggested that an infiltrating cell type is at least partially responsible for the observed difference in in vivo wound healing. Transfer of WT bone marrow cells into lethally irradiated Cd1d−/− mice did not rescue the wound healing defect observed in Cd1d−/− mice. Interestingly, transfer of Cd1d−/− bone marrow into WT mice caused a delay in wound healing. Analysis of wounded skin demonstrated that significantly fewer macrophages and LCs were present in Cd1d−/− epidermis. We conclude that the Cd1d-mediated wound healing defect is dependent on both resident LCs and infiltrating macrophages, and continue to investigate how Cd1d expressed by LCs promotes wound repair as studies have shown that LCs have an immunosuppressive effect in models of contact hypersensitivity and UVB-induced inflammation.

Hepatitis C virus (HCV) infects up to 1.8% of the US general population, although the rate is significantly higher in military veterans at 5.4-20%. Early detection and accurate diagnosis are critical as chronic HCV infection can lead to liver cirrhosis and hepatocellular carcinoma. Genotype analysis has both therapeutic and prognostic importance in patients with HCV infections.We compare two versions of a commonly utilized platform for genotype analysis in HCV infections and review the implications of the results for clinical practice.A retrospective review of 9401 genotype results from 2001-2010 were analyzed. All results were obtained from the James A. Haley VA Medical Center, a large referral veterans' healthcare facility.Genotype 1 was identified in 80.1% of samples, genotype 2 in 11.1%, genotype 3 in 7.4%, and genotype 4 in 1.2%. Genotypes 5 and 6 were rarely present in our patient population. Improvements in diagnostic methodologies over the study period resulted in shifts in genotype subtyping. Specifically, upgrading from the Versant HCV genotype assay (LIPA) (Siemens, Tarrytown, NY) to the newer version 2.0 assay resulted in an increase in identification of genotype 1a by 18.5%.Improved technologies lead to accurate genotype identification and subtyping, both of which have increasingly important prognostic and therapeutic implications. The clinical importance of these results in patients with HCV infections is reviewed.

Injury to the skin, and the subsequent release of noncoding double-stranded RNA (dsRNA) from necrotic keratinocytes, has been identified as an endogenous activator of Toll-like receptor 3 (TLR3). As changes in keratinocyte growth and differentiation follow injury, we hypothesized that TLR3 might trigger some elements of the barrier repair program in keratinocytes. dsRNA was observed to induce TLR3-dependent increases in human keratinocyte mRNA abundance for ABCA12 (ATP-binding cassette, sub-family A, member 12), glucocerebrosidase, acid sphingomyelinase, and transglutaminase 1. Additionally, treatment with dsRNA resulted in increases in sphingomyelin and morphologic changes including increased epidermal lipid staining by Oil Red O and TLR3-dependent increases in lamellar bodies and keratohyalin granules. These observations show that dsRNA can stimulate some events in keratinocytes that are important for skin barrier repair and maintenance.

Prion diseases are fatal, transmissible, neurodegenerative diseases caused by the misfolding of the prion protein (PrP). At present, the molecular pathways underlying prion-mediated neurotoxicity are largely unknown. We hypothesized that the transcriptional regulator of the stress response, heat shock factor 1 (HSF1), would play an important role in prion disease. Uninoculated HSF1 knockout (KO) mice used in our study do not show signs of neurodegeneration as assessed by survival, motor performance, or histopathology. When inoculated with Rocky Mountain Laboratory (RML) prions HSF1 KO mice had a dramatically shortened lifespan, succumbing to disease ≈20% faster than controls. Surprisingly, both the onset of home-cage behavioral symptoms and pathological alterations occurred at a similar time in HSF1 KO and control mice. The accumulation of proteinase K (PK)-resistant PrP also occurred with similar kinetics and prion infectivity accrued at an equal or slower rate. Thus, HSF1 provides an important protective function that is specifically manifest after the onset of behavioral symptoms of prion disease.

The pathogenic mechanism(s) underlying neurodegenerative diseases associated with protein misfolding is unclear. Several studies have implicated ER stress pathways in neurodegenerative conditions, including prion disease, amyotrophic lateral sclerosis, Alzheimer's disease and many others. The ER stress response and upregulation of ER stress-responsive chaperones is observed in the brains of patients affected with Creutzfeldt-Jacob disease and in mouse models of prion diseases. In particular, the processing of caspase-12, an ER-localized caspase, correlates with neuronal cell death in prion disease. However, the contribution of caspase-12 to neurodegeneration has not been directly addressed in vivo. We confirm that ER stress is induced and that caspase-12 is proteolytically processed in a murine model of infectious prion disease. To address the causality of caspase-12 in mediating infectious prion pathogenesis, we inoculated mice deficient in caspase-12 with prions. The survival, behavior, pathology and accumulation of proteinase K-resistant PrP are indistinguishable between caspase-12 knockout and control mice, suggesting that caspase-12 is not necessary for mediating the neurotoxic effects of prion protein misfolding.

The cyclin-dependent kinase inhibitor p27(Kip1) is a powerful molecular determinant of cell cycle progression. Loss of expression of p27(Kip1) has been shown to be predictive of disease progression in several human malignancies. In this study we investigated the expression of two key cell cycle regulators, p27(Kip1) and cyclin E, in the progression of transitional cell carcinoma of the bladder. An immunohistochemical analysis was conducted in a series of 50 bladder tumor specimens, including 3 metastatic lymph nodes, and 7 normal bladder specimens, using specific antibodies against the two regulators of the cell cycle, p27(Kip1) and cyclin E. The degree of immunoreactivity was correlated with the pathological tumor grade, stage, and patient survival. A uniformly intense immunoreactivity for p27(Kip1) and cyclin E was observed in epithelial cells of normal bladder tissue. Malignant bladder tissue demonstrated a heterogeneous pattern of significantly reduced p27(Kip1) and cyclin E immunoreactivity, compared with normal urothelium (P0.01). In addition, there was progressive loss of expression of both cell cycle proteins with increasing tumor grade and pathological stage. Expression of p27(Kip1) was significantly lower in the poorly differentiated tumors (grades III) compared to well and moderately differentiated (grades I and II) tumors (P = 0.004). Moreover, the expression of cyclin E was lower in grade III tumors compared to grade I and II lesions, although this difference failed to reach statistical significance. Most significantly, Kaplan-Meier plots of patient survival show increased mortality risk associated with low levels of p27(Kip1) (P = 0.001) and cyclin E (P = 0.002) expression. This is the first evidence that loss of expression of p27(Kip1) and cyclin E in human bladder transitional cell carcinoma cells correlates with advancing histological aggressiveness and poor patient survival. These results have clinical importance, because they support a role for p27(Kip1) and cyclin E as novel predictive markers of the biological potential of bladder tumors that will enable identification of those tumors most likely to progress to muscle invasive disease and of patient survival.

The molecular mechanisms underlying the therapeutic effect of the alpha1 blocker, doxazosin, on benign prostatic hyperplasia (BPH) are poorly understood. We evaluated the effect of doxazosin on cell proliferation and apoptosis in the prostatic glandular epithelium and stroma of patients with BPH.We examined proliferative and apoptotic activities in prostate specimens of 22 men a mean of 65 years old with BPH before and after doxazosin treatment within the normal therapeutic range. Proliferative and apoptotic indexes were determined using Ki-67 nuclear antigen staining and the terminal transferase end labeling assay, respectively. The smooth muscle cell content in prostatic specimens was identified by smooth muscle alpha-actin, and desmin immunoreactivity and apoptotic indexes were correlated with prostatic stromal tissue regression and improvement in BPH symptoms.In response to doxazosin treatment there were no significant changes in the kinetics of cell proliferation in the prostatic epithelial or stromal cell population. Mean pretreatment baseline apoptosis was 1.9 and 1.0% for the epithelial and stromal prostate components, respectively. Mean apoptotic indexes significantly increased after 3 months of doxazosin treatment in the glandular epithelial (6%) and smooth muscle cells (15%). By 12 months after treatment epithelial apoptosis had decreased to constitutive levels, while the apoptotic index of prostatic stroma cells remained high. Doxazosin induced smooth muscle cell apoptosis correlated with prostatic stromal degeneration, decreased alpha-smooth muscle actin expression and improved BPH symptoms.These findings implicate the induction of prostate apoptosis by doxazosin as a potential molecular mechanism underlying the acute and chronic therapeutic responses of BPH to alpha1 blockade.

We recently discovered a regulatory mechanism that stimulates the production of the multifunctional antimicrobial peptide cathelicidin antimicrobial peptide (CAMP). In response to subtoxic levels of ER stress, increased sphingosine-1-phosphate (S1P) production activates an NFκB→C/EBPα-dependent pathway that enhances CAMP production in cultured human keratinocytes. As the multifunctional stilbenoid compound resveratrol (RESV) increases ceramide (Cer) levels, a precursor of S1P, we hypothesized and assessed whether RESV could exploit the same pathway to regulate CAMP production. Accordingly, RESV significantly increased Cer and S1P levels in cultured keratinocytes, paralleled by increased CAMP mRNA/protein expression. Furthermore, topical RESV also increased murine CAMP mRNA/protein expression in mouse skin. Conversely, blockade of Cer→sphingosine→S1P metabolic conversion, with specific inhibitors of ceramidase or sphingosine kinase, attenuated the expected RESV-mediated increase in CAMP expression. The RESV-induced increase in CAMP expression required both NF-κB and C/EBPα transactivation. Moreover, conditioned media from keratinocytes treated with RESV significantly suppressed Staphylococcus aureus growth. Finally, topical RESV, if not coapplied with a specific inhibitor of sphingosine kinase, blocked S. aureus invasion into murine skin. These results demonstrate that the dietary stilbenoid RESV stimulates S1P signaling of CAMP production through an NF-κB→C/EBPα-dependent mechanism, leading to enhanced antimicrobial defense against exogenous microbial pathogens. © 2013 The Society for Investigative Dermatology.

Atopic dermatitis (AD) is characterized by epidermal tight junction (TJ) defects and a propensity for Staphylococcus aureus skin infections. S. aureus is sensed by many pattern recognition receptors, including Toll-like receptor 2 (TLR2). We hypothesized that an effective innate immune response will include skin barrier repair, and that this response is impaired in AD subjects. S. aureus-derived peptidoglycan (PGN) and synthetic TLR2 agonists enhanced TJ barrier and increased expression of TJ proteins, claudin-1 (CLDN1), claudin-23 (CLDN23), occludin, and Zonulae occludens 1 (ZO-1) in primary human keratinocytes. A TLR2 agonist enhanced skin barrier recovery in human epidermis wounded by tape stripping. Tlr2(-/-) mice had a delayed and incomplete barrier recovery following tape stripping. AD subjects had reduced epidermal TLR2 expression as compared with nonatopic subjects, which inversely correlated (r=-0.654, P=0.0004) with transepidermal water loss (TEWL). These observations indicate that TLR2 activation enhances skin barrier in murine and human skin and is an important part of a wound repair response. Reduced epidermal TLR2 expression observed in AD patients may have a role in their incompetent skin barrier.