Faculty Bibliography
Searched for:
in-biosketch:true
person:orlows01
Total Results:
295
Activation of melanocyte antioxidant response pathways following exposure to vitiligo-inducing phenols: Implications for vitiligo pathogenesis [Meeting Abstract]
Vitiligo is a common disorder characterized by progressive melanocyte death. Vitiligo can be induced in an occupational setting by exposure to vitiligo-inducing phenols (VIPs) such as 4 tert-butyl phenol (4TBP) and monobenzyl ether of hydroquinone (MBEH). These VIPs are believed to specifically target melanocytes due to their structural similarity to tyrosine and competition for binding to tyrosinase, the rate-limiting enzyme for melanin synthesis. By exposing normal melanocytes to VIPs and using microarray analysis and bioinformatics approaches for gene expression profiling, we identified key signaling pathways that are involved in the melanocyte response to VIP exposure. In particular, we hypothesized that exposure of primary human melanocytes to VIPs would result in oxidative stress that triggers antioxidant responses in order to protect melanocytes from cell death. Following melanocyte exposure to VIPs, HO-1 was upregulated (4TBP exposure: 5.49-fold; MBEH exposure: 25.98- fold). HO-1 is a direct target of Nrf2, a key regulator of the Nrf2- ARE antioxidant response. Activation of Nrf2 and its targets, HO- 1 and NQO1, was confirmed by conventional Western blot analysis and quantitative RT-PCR. We are now characterizing the mechanisms that regulate Nrf2 activation in response to VIPs. Additional antioxidants including SOD2 (4TBP: 10.5-fold; MBEH: 38.5-fold), peroxiredoxin 6 (4TBP: 2.44-fold; MBEH: 15.18-fold), and Nrf2 binding partners, MafK (4TBP: 2.12-fold; MBEH: 2.50- fold) and MafF (4TBP: 2.32-fold; MBEH: 3.16-fold) were also upregulated with VIP exposure and are being investigated further. Several studies have revealed dysfunctional antioxidant responses in melanocytes from patients with vitiligo, however the underlying mechanisms that reduce their efficacy are yet to be determined. We hypothesize that investigation of VIP-induced pathways may lead to the characterization of these mechanisms and provide opportunities for development of targeted therapeutics for the treatment of vitiligo
EMBASE:71656845
ISSN: 1755-1471
CID: 1362922
Mucocutaneous Granulomatous Disease in a Patient With Hermansky-Pudlak Syndrome
Importance: Hermansky-Pudlak syndrome (HPS) is a rare genodermatosis characterized by oculocutaneous albinism, platelet dysfunction, and in some patients, pulmonary fibrosis and granulomatous colitis. The granulomatous inflammation in the bowel of patients with HPS can be indistinguishable clinically and histologically from that of Crohn disease (CD); however, mucocutaneous granulomatous lesions have not been considered among the typical skin findings of HPS. Observations: We report a case of an albino woman in her 40s with a history of CD and pulmonary fibrosis who presented with ulcers, plaques, and nodules in the vulva, perineum, inguinal creases, and left axilla. These cutaneous findings had the typical clinical and histologic findings of metastatic cutaneous CD. However, she also had a genetically confirmed diagnosis of HPS. Conclusions and Relevance: It is unclear whether our patient's cutaneous findings were due to CD or secondary to HPS. This report reviews the features of HPS and CD, 2 entities characterized by a granulomatous inflammatory reaction pattern but with unique genetic and clinical features, and discusses the possible overlap between the 2 diagnoses.
PMID: 24989352
ISSN: 2168-6084
CID: 1065872
The cutaneous microbiota in atopic dermatitis changes with topical corticosteroid and bleach bath treatment [Meeting Abstract]
ISI:000334560400622
ISSN: 0022-202x
CID: 997122
Cole disease results from mutations in ENPP1 [Meeting Abstract]
ISI:000334560400415
ISSN: 0022-202x
CID: 997152
Identification of agents that promote endoplasmic reticulum stress using an assay that monitors luciferase secretion
Disruption of protein processing in the secretory pathway is a measurable hallmark of endoplasmic reticulum (ER) stress. Activation of ER stress-mediated pathways has been implicated in numerous diseases, including cancer. To identify agents that induce ER stress, we established a screen for compounds that reduce secretion of the reporter protein Gaussia luciferase (GLUC). Given the clinically validated importance of targeting ER stress-mediated pathways in the treatment of multiple myeloma (MM), we used this hematological malignancy as a model for validating our screening system. From a screen of 2000 marketed drugs and natural compounds in KMS11 and ARP1 MM cells, we identified 97 agents that reduced GLUC secretion in both cell lines by at least 30%. To confirm inducers of ER stress, we applied a secondary screen that assessed splicing of the unfolded protein response (UPR) transcription factor XBP1. One agent, theaflavin-3,3'-digallate (TF-3), was chosen based on its history of safe human consumption and further validated through studies of ER stress-related pathways, including the UPR and apoptosis. Given these promising results, this screen could be a useful tool to identify agents targeting ER stress-related mechanisms in other cellular systems wherein ER stress plays a role in disease etiology.
PMCID:4338999
PMID: 24371212
ISSN: 1087-0571
CID: 836082
Genital melanocytic nevi in children: Experience in a pediatric dermatology practice
BACKGROUND: Little is known about the prevalence and clinical characteristics of genital melanocytic nevi in children. OBJECTIVE: We sought to describe the epidemiology, clinical and dermoscopic features, and natural history of genital nevi in pediatric patients. METHODS: We reviewed charts of 1159 children given the diagnosis of melanocytic nevi over 11 years. Those with genital nevus as a chief symptom were contacted for follow-up. RESULTS: Among children/adolescents evaluated for nevi, the prevalence of genital nevus was 3.5% (40/1159), with a male:female ratio of 1.3:1. There were no statistically significant differences in age, sex, total nevus number, presence of acral and scalp nevi, or family history of dysplastic nevi and melanoma between patients with and without genital nevi. Genital nevus onset was before age 2 years in 63.6% of patients. A globular dermoscopic pattern was observed in 93.3%. Most genital nevi underwent a gradual change in diameter, elevation (becoming soft papules), color, texture, or a combination of these. After median follow-up of 1.5 years, no melanoma or other adverse outcome was observed. LIMITATIONS: This was a retrospective chart analysis and questionnaire-based study of a limited number of patients. CONCLUSIONS: Increased awareness of the clinical characteristics, dermoscopic features, and evolution of genital nevi in children may help to avoid unnecessary surgery.
PMID: 24373784
ISSN: 0190-9622
CID: 811032
IL-17 and TNF Synergistically Modulate Cytokine Expression while Suppressing Melanogenesis: Potential Relevance to Psoriasis
Inflammation-associated pigmentation changes are extremely common, but the etiology underlying this clinical observation remains elusive. Particularly, it is unclear how the myriad of cytokines known to be involved in inflammatory skin processes affect epidermal melanocytes. We sought to determine how IL-17 and tumor necrosis factor (TNF) influence normal human melanocytes, as these two cytokines have been implicated in various skin diseases. IL-17 and TNF jointly stimulated broad inductions of cytokines, including melanoma mitogens CXCL1 and IL-8. Moreover, IL-17 and TNF synergistically inhibited pigmentation-related signaling and melanin production, and induced keratinocyte production of beta-defensin 3, an antagonist for melanocortin 1 receptor. When analyzing psoriasis lesions that are known to overexpress IL-17 and TNF, we observed an increase in melanocyte number and a simultaneous decrease in pigmentation signaling. Furthermore, therapeutic neutralization of TNF and IL-17 with mAbs resulted in a rapid recovery of pigment gene expression in psoriasis lesions. These results demonstrate that IL-17 and TNF can affect both the growth and pigment production of melanocytes, which may contribute to the pigmentation changes associated with psoriasis. These findings may allow the development of novel therapeutics for pigmentary disorders and bring new insights into the immune milieu surrounding melanocytes and related neoplasms.
PMCID:3830693
PMID: 23732752
ISSN: 0022-202x
CID: 666502
Cole Disease Results from Mutations in ENPP1
The coexistence of abnormal keratinization and aberrant pigmentation in a number of cornification disorders has long suggested a mechanistic link between these two processes. Here, we deciphered the genetic basis of Cole disease, a rare autosomal-dominant genodermatosis featuring punctate keratoderma, patchy hypopigmentation, and uncommonly, cutaneous calcifications. Using a combination of exome and direct sequencing, we showed complete cosegregation of the disease phenotype with three heterozygous ENPP1 mutations in three unrelated families. All mutations were found to affect cysteine residues in the somatomedin-B-like 2 (SMB2) domain in the encoded protein, which has been implicated in insulin signaling. ENPP1 encodes ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), which is responsible for the generation of inorganic pyrophosphate, a natural inhibitor of mineralization. Previously, biallelic mutations in ENPP1 were shown to underlie a number of recessive conditions characterized by ectopic calcification, thus providing evidence of profound phenotypic heterogeneity in ENPP1-associated genetic diseases.
PMCID:3791268
PMID: 24075184
ISSN: 0002-9297
CID: 602862
Loss of Oca2 disrupts the unfolded protein response and increases resistance to endoplasmic reticulum stress in melanocytes
Accumulation of proteins in the endoplasmic reticulum (ER) typically induces stress and initiates the unfolded protein response (UPR) to facilitate recovery. If homeostasis is not restored, apoptosis is induced. However, adaptation to chronic UPR activation can increase resistance to subsequent acute ER stress. We therefore investigated adaptive mechanisms in Oculocutaneous albinism type 2 (Oca2)-null melanocytes where UPR signaling is arrested despite continued tyrosinase accumulation leading to resistance to the chemical ER stressor thapsigargin. Although thapsigargin triggers UPR activation, instead of Perk-mediated phosphorylation of eIF2alpha, in Oca2-null melanocytes, eIF2alpha was rapidly dephosphorylated upon treatment. Dephosphorylation was mediated by the Gadd34-PP1alpha phosphatase complex. Gadd34-complex inhibition blocked eIF2alpha dephosphorylation and significantly increased Oca2-null melanocyte sensitivity to thapsigargin. Thus, Oca2-null melanocytes adapt to acute ER stress by disruption of pro-apoptotic Perk signaling, which promotes cell survival. This is the first study to demonstrate rapid eIF2alpha dephosphorylation as an adaptive mechanism to ER stress.
PMCID:3832131
PMID: 23962237
ISSN: 1755-1471
CID: 586232
Neutrophil-rich lymphomatoid papulosis in an adolescent [Meeting Abstract]
A 14-year-old boy presented with a 2-month history of recurrent crops of tender, erythematous papules. Cultures for infectious organisms (viral and bacterial) were negative. Biopsies revealed a neutrophil-dense infiltrate with numerous enlarged mononuclear cells reactive for CD30, CD3, and CD4 with a small subset reactive for CD56, TIA1, and GranzymeB. Special stains for fungal and bacterial microorganisms were negative. A diagnosis of neutrophilrich (pyogenic) lymphomatoid papulosis (LyP) was made. Classic LyP is rare in children, and the neutrophil-rich variant has not been described extensively in the literature. In this histopathologic setting, the atypical lymphocytes may be obscured but made more apparent with immunohistochemistry. Cases of neutrophil-rich anaplastic large cell lymphoma have been described and have a similar histologic appearance to our case but are generally in adults and present as solitary tumors on the face. The histopathologic differential diagnosis includes benign processes with CD30+ mononuclear cells in addition to infection processes and neutrophilic dermatoses
EMBASE:71163157
ISSN: 0193-1091
CID: 550222
