There has been no consistent conclusion on whether Sarcoptes mites parasitizing in humans and animals are the same species. To identify Sarcoptes (S.) hominis and S. canis in China, gDNA was extracted from individual mites (five from patients with scabies and five from dogs with mange) for amplification of rDNA ITS2, mtDNA 16S, and cox1 fragment sequences. Then, the sequences obtained were aligned with those from different hosts and geographical locations retrieved from GenBank and sequence analyses were conducted. Phylogenetic trees based on 317-bp mtDNA cox1 showed five distinctive branches (species) of Sarcoptes mites, four for S. hominis (S. hominis Chinese, S. nr. hominis Chinese, S. hominis Australian, and S. hominis Panamanian) and one for S. animal (S. animal). S. animal included mites from nine animal species, with S. canis China, S. canis Australia, and S. canis USA clustering as a subbranch. Further sequence divergence analysis revealed no overlap between intraspecific (≤ 2.6 %) and interspecific (2.6-10.5 %) divergences in 317-bp mtDNA cox1. However, overlap was detected between intra- and interspecific divergences in 311-bp rDNA ITS2 or 275-bp mtDNA 16S when the divergences exceeded 1.0 %, which resulted in failure in identification of Sarcoptes. The results showed that the 317-bp mtDNA cox1 could be used as a DNA barcode for molecular identification of Sarcoptes mites. In addition, geographical isolation was observed between S. hominis Chinese, S. hominis Australian, and S. hominis Panamanian, but not between all S. canis. S. canis and the other S. animal belonged to the same species.
IFAP syndrome is a rare genetic disorder characterized by ichthyosis follicularis, atrichia, and photophobia. Previous research found that mutations in MBTPS2, encoding site-2-protease (S2P), underlie X-linked IFAP syndrome. The present report describes the identification via whole-exome sequencing of three heterozygous mutations in SREBF1 in 11 unrelated, ethnically diverse individuals with autosomaldominant IFAP syndrome. SREBF1 encodes sterol regulatory element-binding protein 1 (SREBP1), which promotes the transcription of lipogenes involved in the biosynthesis of fatty acids and cholesterols. This process requires cleavage of SREBP1 by site-1-protease (S1P) and S2P and subsequent translocation into the nucleus where it binds to sterol regulatory elements (SRE). The three detected SREBF1 mutations caused substitution or deletion of residues 527, 528, and 530, which are crucial for S1P cleavage. In vitro investigation of SREBP1 variants demonstrated impaired S1P cleavage, which prohibited nuclear translocation of the transcriptionally active form of SREBP1. As a result, SREBP1 variants exhibited significantly lower transcriptional activity compared to the wild-type, as demonstrated via luciferase reporter assay. RNA sequencing of the scalp skin from IFAP-affected individuals revealed a dramatic reduction in transcript levels of low-density lipoprotein receptor (LDLR) and of keratin genes known to be expressed in the outer root sheath of hair follicles. An increased rate of in situ keratinocyte apoptosis, which might contribute to skin hyperkeratosis and hypotrichosis, was also detected in scalp samples from affected individuals. Together with previous research, the present findings suggest that SREBP signaling plays an essential role in epidermal differentiation, skin barrier formation, hair growth, and eye function.
MicroRNAs (miRNAs) participate in the development and progression of melanoma. However, while dysregulation of microRNA-378 (miR-378) has been seen in various cancer types, its clinical importance and function in melanoma is poorly elucidated. In this work, miR-378 expression in melanoma and in adjacent non-cancerous tissue was evaluated with quantitative real time polymerase chain reaction (qRT-PCR). A series of assays (wound healing, Transwell and nude mouse subcutaneous tumor model) were used to investigate the implications of abnormal miR-378 regulation on melanoma cell migration and invasion in vitro, and on tumorigenicity in vivo. Prediction and conformation of the miR-378 target gene was undertaken using bioinformatic analysis and luciferase reporter system. Expression of miR-378 was often increased in melanoma, and shown to potentiate its migration, invasion and tumorigenicity. miR-378 acted, at least partially, through inhibition of the potential target FOXN3 and via Wnt/β-catenin pathway activation. The findings indicate that miR-378 triggers melanoma development and progression. This microRNA could be a novel diagnostic and prognostic biological marker, and provide utility for targeted treatment of melanoma.
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