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Browsing by Author "Department of Dermatology, School of Medicine"
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Item Altered mRNA Splicing in SMN-Depleted Motor Neuron-Like Cells(Public Library of Science (PLoS), 2016) Custer, Sara K.; Gilson, Timra D.; Li, Hongxia; Todd, A. Gary; Astroski, Jacob W.; Lin, Hai; Liu, Yunlong; Androphy, Elliot J.; Department of Dermatology, School of MedicineSpinal muscular atrophy (SMA) is an intractable neurodegenerative disease afflicting 1 in 6-10,000 live births. One of the key functions of the SMN protein is regulation of spliceosome assembly. Reduced levels of the SMN protein that are observed in SMA have been shown to result in aberrant mRNA splicing. SMN-dependent mis-spliced transcripts in motor neurons may cause stresses that are particularly harmful and may serve as potential targets for the treatment of motor neuron disease or as biomarkers in the SMA patient population. We performed deep RNA sequencing using motor neuron-like NSC-34 cells to screen for SMN-dependent mRNA processing changes that occur following acute depletion of SMN. We identified SMN-dependent splicing changes, including an intron retention event that results in the production of a truncated Rit1 transcript. This intron-retained transcript is stable and is mis-spliced in spinal cord from symptomatic SMA mice. Constitutively active Rit1 ameliorated the neurite outgrowth defect in SMN depleted NSC-34 cells, while expression of the truncated protein product of the mis-spliced Rit1 transcript inhibited neurite extension. These results reveal new insights into the biological consequence of SMN-dependent splicing in motor neuron-like cells.Item Dilysine motifs in exon 2b of SMN protein mediate binding to the COPI vesicle protein α-COP and neurite outgrowth in a cell culture model of spinal muscular atrophy(Oxford Journals, 2013-10-15) Custer, Sara K.; Todd, Adrian G.; Singh, Natalia N.; Androphy, Elliot J.; Department of Dermatology, School of MedicineSpinal muscular atrophy (SMA) is a devastating neuromuscular disorder that stems from low levels of survival of motor neuron (SMN) protein. The processes that cause motor neurons and muscle cells to become dysfunctional are incompletely understood. We are interested in neuromuscular homeostasis and the stresses put upon that system by loss of SMN. We recently reported that α-COP, a member of the coatomer complex of coat protein I (COPI) vesicles, is an SMN-binding partner, implicating this protein complex in normal SMN function. To investigate the functional significance of the interaction between α-COP and SMN, we constructed an inducible NSC-34 cell culture system to model the consequences of SMN depletion and find that depletion of SMN protein results in shortened neurites. Heterologous expression of human SMN, and interestingly over-expression of α-COP, restores normal neurite length and morphology. Mutagenesis of the canonical COPI dilysine motifs in exon 2b results in failure to bind to α-COP and abrogates the ability of human SMN to restore neurite outgrowth in SMN-depleted motor neuron-like NSC-34 cells. We conclude that the interaction between SMN and α-COP serves an important function in the growth and maintenance of motor neuron processes and may play a significant role in the pathogenesis of SMA.Item Epithelioid Malignant Mesothelioma Metastatic to the Skin: A Case Report and Review of the Literature(Wiley, 2017) Ward, Rachel Elizabeth; Ali, Stefanie Ann; Kuhar, Matthew; Department of Dermatology, School of MedicineMalignant mesothelioma (MM) is an aggressive and invasive neoplasm primarily affecting the pleura, peritoneum and pericardium. While mesothelioma commonly metastasizes to visceral organs, it has rarely been documented to involve the skin and subcutaneous tissue. There is a paucity of reports of cutaneous metastatic mesothelioma, and histologic examination is often challenging because the tumor closely mimics other primary and metastatic neoplasms. We report a case of a 75-year-old man presenting with a firm, hard nodule on his upper back, which on initial histologic evaluation resembled metastatic adenocarcinoma. However, upon review of his medical history and immunohistochemical evaluation of the lesion, the diagnosis of epithelioid MM metastatic to the skin was rendered. The purpose of this case report and review of the literature is to summarize the most effective available immunostains to aid in the diagnosis of this challenging entity, highlight the histologic similarities between metastatic epithelioid MM and other primary and metastatic neoplasms of the skin, and provide prognostic information for these rare tumors.Item Multifocal Rosai-Dorfman disease with involvement of the pinna(Elsevier, 2017-05) Hirt, Molly B.; Heskett, Jordan; Veerula, Vindhya; Warren, Simon; Avashia-Khemka, Nidhi; Mark, Lawrence A.; Department of Dermatology, School of MedicineItem Peters anomaly in PHACE syndrome(Elsevier, 2017-08) Shabeeb, Nadine M.; Plager, David A.; Haggstrom, Anita N.; Department of Dermatology, School of MedicinePHACE syndrome is a rare neurocutaneous disorder, with a complex pathogenesis. It presents with a large facial hemangioma associated with anomalies of the posterior fossa of the brain, arterial anomalies, cardiac anomalies, coarctation of the aorta, and eye anomalies. Ocular abnormalities are rare. We report the first published case of an infant with PHACE syndrome and Peters anomaly.Item Small Molecules in Development for the Treatment of Spinal Muscular Atrophy(ACS, 2016-08) Calder, Alyssa N.; Androphy, Elliot J.; Hodgetts, Kevin J.; Department of Dermatology, School of MedicineSpinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disease resulting from pathologically low levels of survival motor neuron (SMN) protein. The majority of mRNA from the SMN2 allele undergoes alternative splicing and excludes critical codons, causing an SMN protein deficiency. While there is currently no FDA-approved treatment for SMA, early therapeutic efforts have focused on testing repurposed drugs such as phenylbutyrate (2), valproic acid (3), riluzole (6), hydroxyurea (7), and albuterol (9), none of which has demonstrated clinical effectiveness. More recently, clinical trials have focused on novel small-molecule compounds identified from high-throughput screening and medicinal chemistry optimization such as olesoxime (11), CK-2127107, RG7800, LMI070, and RG3039 (17). In this paper, we review both repurposed drugs and small-molecule compounds discovered following medicinal chemistry optimization for the potential treatment of SMA.