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Recent documents in eScholarship@UMMS
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Simvastatin prevents and reverses depigmentation in a mouse model of vitiligo

Thu, 04/20/2017 - 12:38pm

Vitiligo is a common autoimmune disease of the skin that results in disfiguring white spots. There are no Food and Drug Administration (FDA)-approved treatments, and current treatments are time-consuming, expensive, and of low efficacy. We sought to identify new treatments for vitiligo, and first considered repurposed medications because of the availability of safety data and expedited regulatory approval. We previously reported that the IFN-gamma-induced chemokine CXCL10 is expressed in lesional skin from vitiligo patients, and that it is critical for the progression and maintenance of depigmentation in our mouse model of vitiligo. We hypothesized that targeting IFN-gamma signaling might be an effective new treatment strategy. Activation of signal transducer and activator of transcription 1 (STAT1) is required for IFN-gamma signaling and recent studies revealed that simvastatin, an FDA-approved cholesterol-lowering medication, inhibited STAT1 activation in vitro. Therefore, we hypothesized that simvastatin may be an effective treatment for vitiligo. We found that simvastatin both prevented and reversed depigmentation in our mouse model of vitiligo, and reduced the number of infiltrating autoreactive CD8(+) T cells in the skin. Treatment of melanocyte-specific, CD8(+) T cells in vitro decreased proliferation and IFN-gamma production, suggesting additional effects of simvastatin directly on T cells. Based on these data, simvastatin may be a safe, targeted treatment option for patients with vitiligo.

The deep penetrating nevus

Thu, 04/20/2017 - 12:38pm

The deep penetrating nevus (DPN), also known as the plexiform spindle cell nevus, is a pigmented lesion that commonly arises on the head and neck in the first few decades of life. Histopathologically, the DPN is wedge-shaped and contains melanocytes that exhibit deep infiltration into the dermis. Given these features, DPN may clinically and histopathologically mimic malignant melanoma, sparking confusion about the appropriate evaluation and management of these lesions. The goal of this review is to summarize the clinical and histopathological features of DPN and to discuss diagnostic and treatment strategies for dermatologists.

Child abuse masquerading as a soft tissue sarcoma

Thu, 04/20/2017 - 12:38pm

Pediatric fasciitides are rare benign lesions that may clinically mimic a malignant sarcoma. Nodular fasciitis, the most common of these fasciitides, rarely occurs in children younger than 5 years of age. Often there is a history of preceding trauma. Herein, we report the case of a 5-month-old boy diagnosed with nodular fasciitis in the setting of nonaccidental trauma.

Excipients in Oral Antihistamines Can Perpetuate Allergic Contact Dermatitis

Thu, 04/20/2017 - 12:38pm

Propylene glycol is a well-documented causative agent of allergic contact dermatitis (ACD). It is also reported to cause systemic dermatitis after ingestion of foods or medicines containing it and after intravenous injection of a medicine with propylene glycol in its base. We describe two adolescents with sensitivity to propylene glycol confirmed by patch testing whose dermatitis improved dramatically after cessation of oral antihistamines containing propylene glycol. We report these cases to alert providers to the potential for worsening of ACD due to systemic exposure to propylene glycol in patients with a cutaneous sensitivity to the allergen.

Gene expression profiling of skeletal muscles treated with a soluble activin type IIB receptor

Tue, 04/18/2017 - 9:01pm

Inhibition of the myostatin signaling pathway is emerging as a promising therapeutic means to treat muscle wasting and degenerative disorders. Activin type IIB receptor (ActRIIB) is the putative myostatin receptor, and a soluble activin receptor (ActRIIB-Fc) has been demonstrated to potently inhibit a subset of transforming growth factor (TGF)-beta family members including myostatin. To determine reliable and valid biomarkers for ActRIIB-Fc treatment, we assessed gene expression profiles for quadriceps muscles from mice treated with ActRIIB-Fc compared with mice genetically lacking myostatin and control mice. Expression of 134 genes was significantly altered in mice treated with ActRIIB-Fc over a 2-wk period relative to control mice (fold change > 1.5, P < 0.001), whereas the number of significantly altered genes in mice treated for 2 days was 38, demonstrating a time-dependent response to ActRIIB-Fc in overall muscle gene expression. The number of significantly altered genes in Mstn(-/-) mice relative to control mice was substantially higher (360), but for most of these genes the expression levels in the 2-wk treated mice were closer to the levels in the Mstn(-/-) mice than in control mice (P < 10(-)(3)(0)). Expression levels of 30 selected genes were further validated with quantitative real-time polymerase chain reaction (qPCR), and a correlation of > /= 0.89 was observed between the fold changes from the microarray analysis and the qPCR analysis. These data suggest that treatment with ActRIIB-Fc results in overlapping but distinct gene expression signatures compared with myostatin genetic mutation. Differentially expressed genes identified in this study can be used as potential biomarkers for ActRIIB-Fc treatment, which is currently in clinical trials as a therapeutic agent for muscle wasting and degenerative disorders.

A role for Zic1 and Zic2 in Myf5 regulation and somite myogenesis

Tue, 04/18/2017 - 9:01pm

Zic genes encode a conserved family of zinc finger proteins with essential functions in neural development and axial skeletal patterning in the vertebrate embryo. Zic proteins also function as Gli co-factors in Hedgehog signaling. Here, we report that Zic genes have a role in Myf5 regulation for epaxial somite myogenesis in the mouse embryo. In situ hybridization studies show that Zic1, 2, and 3 transcripts are expressed in Myf5-expressing epaxial myogenic progenitors in the dorsal medial dermomyotome of newly forming somites, and immunohistological studies show that Zic2 protein is co-localized with Myf5 and Pax3 in the dorsal medial lip of the dermomyotome, but is not expressed in the forming myotome. In functional reporter assays, Zic1 and Zic2, but not Zic3, potentiate the transactivation of Gli-dependent Myf5 epaxial somite-specific (ES) enhancer activity in 3T3 cells, and Zic1 activates endogenous Myf5 expression in 10T1/2 cells and in presomitic mesoderm explants. Zic2 also co-immunoprecipitates with Gli2, indicating that Zic2 forms complexes with Gli2 to promote Myf5 expression. Genetic studies show that, although Zic2 and Zic1 are activated normally in sonic hedgehog(-/-) mutant embryos, Myf5 expression in newly forming somites is deficient in both sonic hedgehog(-/-) and in Zic2(kd/kd) mutant mouse embryos, providing further evidence that these Zic genes are upstream regulators of Hedgehog-mediated Myf5 activation. Myf5 activation in newly forming somites is delayed in Zic2 mutant embryos until the time of Zic1 activation, and both Zic2 and Myf5 require noggin for their activation.

A new role for Hedgehogs in juxtacrine signaling

Tue, 04/18/2017 - 9:01pm

The Hedgehog pathway plays important roles in embryonic development, adult stem cell maintenance and tumorigenesis. In mammals these effects are mediated by Sonic, Desert and Indian Hedgehog (Shh, Dhh and Ihh). Shh undergoes autocatalytic cleavage and dual lipidation prior to secretion and forming a response gradient. Post-translational processing and secretion of Dhh and Ihh ligands has not previously been investigated. This study reports on the synthesis, processing, secretion and signaling activities of SHH, IHH and DHH preproteins expressed in cultured cells, providing unexpected evidence that DHH does not undergo substantial autoprocessing or secretion, and does not function in paracrine signaling. Rather, DHH functions as a juxtacrine signaling ligand to activate a cell contact-mediated HH signaling response, consistent with its localised signaling in vivo. Further, the LnCAP prostate cancer cell, when induced to express endogenous DHH and SHH, is active only in juxtacrine signaling. Domain swap studies reveal that the C-terminal domain of HH regulates its processing and secretion. These findings establish a new regulatory role for HHs in cell-mediated juxtacrine signaling in development and cancer.

Mouse Dux is myotoxic and shares partial functional homology with its human paralog DUX4

Tue, 04/18/2017 - 9:01pm

D4Z4 repeats are present in at least 11 different mammalian species, including humans and mice. Each repeat contains an open reading frame encoding a double homeodomain (DUX) family transcription factor. Aberrant expression of the D4Z4 ORF called DUX4 is associated with the pathogenesis of Facioscapulohumeral muscular dystrophy (FSHD). DUX4 is toxic to numerous cell types of different species, and over-expression caused dysmorphism and developmental arrest in frogs and zebrafish, embryonic lethality in transgenic mice, and lesions in mouse muscle. Because DUX4 is a primate-specific gene, questions have been raised about the biological relevance of over-expressing it in non-primate models, as DUX4 toxicity could be related to non-specific cellular stress induced by over-expressing a DUX family transcription factor in organisms that did not co-evolve its regulated transcriptional networks. We assessed toxic phenotypes of DUX family genes, including DUX4, DUX1, DUX5, DUXA, DUX4-s, Dux-bl and mouse Dux. We found that DUX proteins were not universally toxic, and only the mouse Dux gene caused similar toxic phenotypes as human DUX4. Using RNA-seq, we found that 80% of genes upregulated by Dux were similarly increased in DUX4-expressing cells. Moreover, 43% of Dux-responsive genes contained ChIP-seq binding sites for both Dux and DUX4, and both proteins had similar consensus binding site sequences. These results suggested DUX4 and Dux may regulate some common pathways, and despite diverging from a common progenitor under different selective pressures for millions of years, the two genes maintain partial functional homology.

Homologous Transcription Factors DUX4 and DUX4c Associate with Cytoplasmic Proteins during Muscle Differentiation

Tue, 04/18/2017 - 9:01pm

Hundreds of double homeobox (DUX) genes map within 3.3-kb repeated elements dispersed in the human genome and encode DNA-binding proteins. Among these, we identified DUX4, a potent transcription factor that causes facioscapulohumeral muscular dystrophy (FSHD). In the present study, we performed yeast two-hybrid screens and protein co-purifications with HaloTag-DUX fusions or GST-DUX4 pull-down to identify protein partners of DUX4, DUX4c (which is identical to DUX4 except for the end of the carboxyl terminal domain) and DUX1 (which is limited to the double homeodomain). Unexpectedly, we identified and validated (by co-immunoprecipitation, GST pull-down, co-immunofluorescence and in situ Proximal Ligation Assay) the interaction of DUX4, DUX4c and DUX1 with type III intermediate filament protein desmin in the cytoplasm and at the nuclear periphery. Desmin filaments link adjacent sarcomere at the Z-discs, connect them to sarcolemma proteins and interact with mitochondria. These intermediate filament also contact the nuclear lamina and contribute to positioning of the nuclei. Another Z-disc protein, LMCD1 that contains a LIM domain was also validated as a DUX4 partner. The functionality of DUX4 or DUX4c interactions with cytoplasmic proteins is underscored by the cytoplasmic detection of DUX4/DUX4c upon myoblast fusion. In addition, we identified and validated (by co-immunoprecipitation, co-immunofluorescence and in situ Proximal Ligation Assay) as DUX4/4c partners several RNA-binding proteins such as C1QBP, SRSF9, RBM3, FUS/TLS and SFPQ that are involved in mRNA splicing and translation. FUS and SFPQ are nuclear proteins, however their cytoplasmic translocation was reported in neuronal cells where they associated with ribonucleoparticles (RNPs). Several other validated or identified DUX4/DUX4c partners are also contained in mRNP granules, and the co-localizations with cytoplasmic DAPI-positive spots is in keeping with such an association. Large muscle RNPs were recently shown to exit the nucleus via a novel mechanism of nuclear envelope budding. Following DUX4 or DUX4c overexpression in muscle cell cultures, we observed their association with similar nuclear buds. In conclusion, our study demonstrated unexpected interactions of DUX4/4c with cytoplasmic proteins playing major roles during muscle differentiation. Further investigations are on-going to evaluate whether these interactions play roles during muscle regeneration as previously suggested for DUX4c.

Muscle dysfunction in a zebrafish model of Duchenne muscular dystrophy

Tue, 04/18/2017 - 9:01pm

Sapje zebrafish lack the protein dystrophin and are the smallest vertebrate model of Duchenne muscular dystrophy (DMD). Their small size makes them ideal for large-scale drug discovery screens. However, the extent that sapje mimic the muscle dysfunction of higher vertebrate models of DMD is unclear. We used an optical birefringence assay to differentiate affected dystrophic sapje larvae from their unaffected siblings and then studied trunk muscle contractility at 4-7 days post fertilization. Preparation cross-sectional area (CSA) was similar for affected and unaffected larvae, yet tetanic forces of affected preparations were only 30-60% of normal. ANCOVA indicated that the linear relationship observed between tetanic force and CSA for unaffected preparations was absent in the affected population. Consequently, the average force/CSA of affected larvae was depressed 30-70%. Disproportionate reductions in twitch vs. tetanic force, and a slowing of twitch tension development and relaxation, indicated that the myofibrillar disorganization evident in the birefringence assay could not explain the entire force loss. Single eccentric contractions, in which activated preparations were lengthened 5-10%, resulted in tetanic force deficits in both groups of larvae. However, deficits of affected preparations were 3 to 5-fold greater at all strains and ages, even after accounting for any recovery. Based on these functional assessments, we conclude that the sapje mutant zebrafish is a phenotypically severe model of DMD. The severe contractile deficits of sapje larvae represent novel physiological endpoints for therapeutic drug screening.

Antisense Oligonucleotides Used to Target the DUX4 mRNA as Therapeutic Approaches in FaciosScapuloHumeral Muscular Dystrophy (FSHD)

Tue, 04/18/2017 - 9:00pm

FacioScapuloHumeral muscular Dystrophy (FSHD) is one of the most prevalent hereditary myopathies and is generally characterized by progressive muscle atrophy affecting the face, scapular fixators; upper arms and distal lower legs. The FSHD locus maps to a macrosatellite D4Z4 repeat array on chromosome 4q35. Each D4Z4 unit contains a DUX4 gene; the most distal of which is flanked by a polyadenylation site on FSHD-permissive alleles, which allows for production of stable DUX4 mRNAs. In addition, an open chromatin structure is required for DUX4 gene transcription. FSHD thus results from a gain of function of the toxic DUX4 protein that normally is only expressed in germ line and stem cells. Therapeutic strategies are emerging that aim to decrease DUX4 expression or toxicity in FSHD muscle cells. We review here the heterogeneity of DUX4 mRNAs observed in muscle and stem cells; and the use of antisense oligonucleotides (AOs) targeting the DUX4 mRNA to interfere either with transcript cleavage/polyadenylation or intron splicing. We show in primary cultures that DUX4-targeted AOs suppress the atrophic FSHD myotube phenotype; but do not improve the disorganized FSHD myotube phenotype which could be caused by DUX4c over-expression. Thus; DUX4c might constitute another therapeutic target in FSHD.

SMCHD1 mutations associated with a rare muscular dystrophy can also cause isolated arhinia and Bosma arhinia microphthalmia syndrome

Tue, 04/18/2017 - 9:00pm

Arhinia, or absence of the nose, is a rare malformation of unknown etiology that is often accompanied by ocular and reproductive defects. Sequencing of 40 people with arhinia revealed that 84% of probands harbor a missense mutation localized to a constrained region of SMCHD1 encompassing the ATPase domain. SMCHD1 mutations cause facioscapulohumeral muscular dystrophy type 2 (FSHD2) via a trans-acting loss-of-function epigenetic mechanism. We discovered shared mutations and comparable DNA hypomethylation patterning between these distinct disorders. CRISPR/Cas9-mediated alteration of smchd1 in zebrafish yielded arhinia-relevant phenotypes. Transcriptome and protein analyses in arhinia probands and controls showed no differences in SMCHD1 mRNA or protein abundance but revealed regulatory changes in genes and pathways associated with craniofacial patterning. Mutations in SMCHD1 thus contribute to distinct phenotypic spectra, from craniofacial malformation and reproductive disorders to muscular dystrophy, which we speculate to be consistent with oligogenic mechanisms resulting in pleiotropic outcomes.

Validity of the 6 minute walk test in facioscapulohumeral muscular dystrophy

Tue, 04/18/2017 - 9:00pm

INTRODUCTION: In preparation for future clinical trials, we determined the reliability, relationship to measures of disease severity, and consistency across sites of the 6 Minute Walk Test (6MWT) in patients with facioscapulohumeral muscular dystrophy (FSHD).

METHODS: Genetically defined and clinically affected FSHD participants at 2 sites performed the 6MWT, the Timed Up and Go, and the 30 foot Go/Timed 10 meter test as measures of mobility using standard procedures.

RESULTS: Eight-six participants representing the full range of severity performed the 6MWT. The mean 6MWT distance was 404.3 meters (SD 123.9), with no difference between sites. The 6MWT was reliable (n = 25; intraclass correlation coefficient = 0.99) and demonstrated moderate to strong correlations with lower extremity strength, functional outcomes, and FSHD Clinical Score.

CONCLUSIONS: The 6MWT is reliable and is associated with other measures of FSHD disease severity. Future directions include assessing its sensitivity to disease progression. .

Bone Health in Facioscapulohumeral Muscular Dystrophy: A Cross-Sectional Study

Tue, 04/18/2017 - 9:00pm

INTRODUCTION: We provide a comprehensive overview of bone health in facioscapulohumeral muscular dystrophy (FSHD).

METHODS: Ninety-four adult individuals with FSHD1 from two sites were included in this cross-sectional study. Clinical characteristics and determinants of bone health were examined. Relationships between bone mineral density (BMD), strength and function were explored.

RESULTS: Nearly a third of subjects were deficient in vitamin D3. Mean whole body BMD z-score was -0.7; 11% had greater than age-related reductions in whole body BMD (z-score < -2.0). Whole body and regional BMD were associated with strength and function. Thirty-six percent had a history of fractures. Likelihood for fractures was reduced for those with normal whole body BMD (OR=0.25, 95% CI: 0.04-0.78).

DISCUSSION: A diagnosis of FSHD is not necessarily predictive of reduced BMD or increased fracture rate. Given the considerable variability of bone health in the FSHD population, strength and function can serve as predictors of BMD. This article is protected by copyright.

Safety and efficacy of high-dose tamoxifen and sulindac for desmoid tumor in children: results of a Children's Oncology Group (COG) phase II study

Tue, 04/18/2017 - 12:08pm

BACKGROUND: Desmoid fibromatosis (desmoid tumor, DT) is a soft tissue neoplasm prone to recurrence despite complete surgical resection. Numerous small retrospective reports suggest that non-cytotoxic chemotherapy using tamoxifen and sulindac may be effective for DT. We evaluated the safety and efficacy of tamoxifen and sulindac in a prospective phase II study within the Children's Oncology Group.

PROCEDURES: Eligible patients were (PFS). Patients received tamoxifen and sulindac daily for 12 months or until disease progression or intolerable toxicity occurred. Response was assessed by magnetic resonance imaging.

RESULTS: Fifty-nine eligible patients were enrolled from 2004 to 2009; 78% were 10-18 years old. Twenty-two (38%) were previously untreated; 15 (41%) of the remaining 37 enrolling with recurrent DT had prior systemic chemotherapy and six (16%) had prior radiation. No life-threatening toxicity was reported. Twelve (40%) of 30 females developed ovarian cysts, which were asymptomatic in 11 cases. Ten patients completed therapy without disease progression or discontinuing treatment. Responses included four partial and one complete (5/59, 8%). The estimated 2-year PFS and survival rates were 36% (95% confidence interval: 0.23-0.48) and 96%, respectively. All three deaths were due to progressive DT.

CONCLUSIONS: Tamoxifen and sulindac caused few serious side effects in children with DT, although ovarian cysts were common. However, the combination showed relatively little activity as measured by response and PFS rates.

Image based feasibility of renal sparing surgery for very low risk unilateral Wilms tumors: a report from the Children's Oncology Group

Tue, 04/18/2017 - 12:08pm

PURPOSE: Nephrectomy with lymph node sampling is the recommended treatment for children with unilateral Wilms tumor under the Children's Oncology Group protocols. Using radiological assessment, we determined the feasibility of performing partial nephrectomy in a select group of patients with very low risk unilateral Wilms tumor.

MATERIALS AND METHODS: We reviewed imaging studies of 60 patients with a mean age of less than 2 years with very low risk unilateral Wilms tumor (mean weight less than 550 gm) to assess the feasibility of partial nephrectomy. We evaluated percentage of salvageable parenchyma, tumor location and anatomical features preventing a nephron sparing approach.

RESULTS: A linear relationship exists between tumor weight and computerized tomography estimated tumor volume. Mean tumor weight in the study population was 315 gm. Partial nephrectomy was deemed feasible in only 5 of 60 patients (8%).

CONCLUSIONS: When considering a select population with very low risk unilateral Wilms tumor (lower volume tumor), only a small percentage of nonpretreated patients are candidates for nephron sparing surgery. .

Children's Oncology Group's 2013 blueprint for research: renal tumors

Tue, 04/18/2017 - 12:08pm

Renal malignancies are among the most prevalent pediatric cancers. The most common is favorable histology Wilms tumor (FHWT), which has 5-year overall survival exceeding 90%. Other pediatric renal malignancies, including anaplastic Wilms tumor, clear cell sarcoma, malignant rhabdoid tumor, and renal cell carcinoma, have less favorable outcomes. Recent clinical trials have identified gain of chromosome 1q as a prognostic marker for FHWT. Upcoming studies will evaluate therapy adjustments based on this and other novel biomarkers. For high-risk renal tumors, new treatment regimens will incorporate biological therapies. A research blueprint, viewed from the perspective of the Children's Oncology Group, is presented.

A Pilot Study (SWOG S0429) of Weekly Cetuximab and Chest Radiotherapy for Poor-Risk Stage III Non-Small Cell Lung Cancer

Tue, 04/18/2017 - 12:08pm

PURPOSE: Stage III non-small cell lung cancer (NSCLC) patients with poor performance status (PS) or co-morbidities are often not candidates for standard chemoradiotherapy (chemoRT) due to poor tolerance to treatments. A pilot study for poor-risk stage III NSCLC patients was conducted combining cetuximab, a chimeric monoclonal antibody targeting epidermal growth factor receptor (EGFR), with chest radiation (RT).

METHODS: Stage III NSCLC patients with Zubrod PS 2, or Zubrod PS 0-1 with poor pulmonary function and co-morbidities prohibiting chemoRT were eligible. A loading dose of cetuximab (400 mg/m(2)) was delivered week 1, followed by weekly cetuximab (250 mg/m(2))/RT to 64.8 Gy in 1.8 Gy daily fractions, and maintenance weekly cetuximab (250 mg/m(2)) for 2 years or until disease progression. H-score for EGFR protein expression was conducted in available tumors.

RESULTS: Twenty-four patients were enrolled. Twenty-two were assessed for outcome and toxicity. Median survival was 14 months and median progression-free survival was 8 months. The response rate was 47% and disease control rate was 74%. Toxicity assessment revealed 22.7% overall > /=Grade 3 non-hematologic toxicities. Grade 3 esophagitis was observed in one patient (5%). The skin reactions were mostly Grade 1 or 2 except two of 22 (9%) had Grade 3 acne and one of 22 (5%) had Grade 3 radiation skin burn. Grade 3-4 hypomagnesemia was seen in four (18%) patients. One patient (5%) had elevated cardiac troponin and pulmonary emboli. H-score did not reveal prognostic significance. An initially planned second cohort of the study did not commence due to slow accrual, which would have added weekly docetaxel to cetuximab/RT after completion of the first cohort of patients.

CONCLUSION: Concurrent weekly cetuximab/chest RT followed by maintenance cetuximab for poor-risk stage III NSCLC was well tolerated. Further studies with larger sample sizes will be useful to establish the optimal therapeutic ratio of this regimen.