Ultrastructure abnormalities of collagen and elastin in Arab patients with arterial tortuosity syndrome.

Arterial tortuosity syndrome (ATS) is a rare autosomal recessive disease characterized by elongation and tortuosity of the large- and medium-sized arteries. ATS patients display features that are also found in Ehlers-Danlos syndrome (EDS) patients. ATS is caused by pathogenic mutations in the SLC2A10 gene, which encodes for the glucose transporter, GLUT10. This study aimed at examining the ultrastructure of skin for abnormalities that can explain the loose skin and arterial phenotypes of Arab patients with the p.S81R mutation in SLC2A10. Forty-eight patients with SLC2A10 mutation were recruited for this study. Skin biopsy specimens from three children with ATS and a healthy child were examined by electron microscopy to determine the ultrastructure of collagen and elastin. Histopathologic staining of sections from tissue biopsy specimens was also performed. Large spaces were observed among the collagen fibrils in the skin biopsy specimens obtained from ATS patients, suggesting disorganization of the collagen structures. Furthermore, elastin fiber contents and their thickness are reduced in the skin. In small muscular arteries in the skin from ATS patients, discontinuous internal elastic lamina, lack of myofilaments, and disorganized medial smooth muscle cells with vacuolated cytoplasm are present. The disorganization of collagen fibrils and reduced elastin contents in the skin may explain the loose skin phenotype of ATS patients similar to the EDS patients. The lack of elastin in small muscular arteries may have contributed to the development of arterial tortuosity in these patients.

Sanguinarine Induces Apoptosis in Papillary Thyroid Cancer Cells via Generation of Reactive Oxygen Species.

Sanguinarine (SNG), a natural compound with an array of pharmacological activities, has promising therapeutic potential against a number of pathological conditions, including malignancies. In the present study, we have investigated the antiproliferative potential of SNG against two well-characterized papillary thyroid cancer (PTC) cell lines, BCPAP and TPC-1. SNG significantly inhibited cell proliferation of PTC cells in a dose and time-dependent manner. Western blot analysis revealed that SNG markedly attenuated deregulated expression of p-STAT3, without affecting total STAT3, and inhibited growth of PTC via activation of apoptotic and autophagy signaling cascade, as SNG treatment of PTC cells led to the activation of caspase-3 and caspase-8; cleavage of PARP and activation of autophagy markers. Further, SNG-mediated anticancer effects in PTC cells involved the generation of reactive oxygen species (ROS) as N-acetyl cysteine (NAC), an inhibitor of ROS, prevented SNG-mediated antiproliferative, apoptosis and autophagy inducing action. Interestingly, SNG also sensitized PTC cells to chemotherapeutic drug cisplatin, which was inhibited by NAC. Finally, SNG suppressed the growth of PTC thyrospheres and downregulated stemness markers ALDH2 and SOX2. Altogether, the findings of the current study suggest that SNG has anticancer potential against PTC cells as well its derived cancer stem-like cells, most likely via inactivation of STAT3 and its associated signaling molecules.

Ubiquitination of nuclear receptors.

Nuclear receptors (NRs) are cellular proteins, which upon ligand activation, act to exert regulatory control over transcription and subsequent expression. Organized via systemic classification into seven subfamilies, NRs partake in modulating a vast expanse of physiological functions essential for maintenance of life. NRs display particular characteristics towards ubiquitination, the process of addition of specific ubiquitin tags at appropriate locations. Orchestrated through groups of enzymes harboring a diverse array of specialized structural components, the ubiquitination process emphatically alters the fate or downstream effects of NRs. Such influence is especially prominent in transcriptional processes such as promoter clearing for optimization and degradation pathways eliminating or recycling targeted proteins. Ultimately, the ubiquitination of NRs carries significant implications in terms of generating pathological clinical manifestations. Increasing evidence from studies involving patients and disease models suggests a role for ubiquitinated NRs in virtually every organ system. This supports the broad repertoire of roles that NRs play in the body, including modulatory conductors, facilitators, responders to external agents, and critical constituents for pharmacological or biological interventions. This review aims to cover relevant background and mechanisms of NRs and ubiquitination, with a focus towards elucidating subsequent pathophysiology and therapeutics in clinical disorders encompassing such ubiquitinated NRs.

The Molecular Genetics of Autosomal Recessive Nonsyndromic Intellectual Disability: a Mutational Continuum and Future Recommendations.

Intellectual disability (ID) is a clinical manifestation of the central nervous system without any major dysmorphologies of the brain. Biologically it affects learning capabilities, memory, and cognitive functioning. The basic defining features of ID are characterized by IQ<70, age of onset before 18 years, and impairment of at least two of the adaptive skills. Clinically it is classified in a syndromic (with additional abnormalities) and a nonsyndromic form (with only cognitive impairment). The study of nonsyndromic intellectual disability (NSID) can best explain the pathophysiology of cognition, intelligence and memory. Genetic analysis in autosomal recessive nonsyndrmic ID (ARNSID) has mapped 51 disease loci, 34 of which have revealed their defective genes. These genes play diverse physiological roles in various molecular processes, including methylation, proteolysis, glycosylation, signal transduction, transcription regulation, lipid metabolism, ion homeostasis, tRNA modification, ubiquitination and neuromorphogenesis. High-density SNP array and whole exome sequencing has increased the pace of gene discoveries and many new mutations are being published every month. The lack of uniform criteria has assigned multiple identifiers (or accession numbers) to the same MRT locus (e.g. MRT7 and MRT22). Here in this review we describe the molecular genetics of ARNSID, prioritize the candidate genes in uncharacterized loci, and propose a new nomenclature to reorganize the mutation data that will avoid the confusion of assigning duplicate accession numbers to the same ID locus and to make the data manageable in the future as well.

Nonsense mutation in the WDR73 gene is associated with Galloway-Mowat syndrome.

BACKGROUND: Neuroanatomical defects are often present in children with severe developmental delay and intellectual disabilities. Few genetic loci have been associated with disorders of neurodevelopment. Our objective of the present study was to analyse a consanguineous Arab family showing some of the hallmark signs of a rare cerebellar hypoplasia-related neurodevelopmental syndrome as a strategy for discovering a causative genetic mutation. METHODS: We used whole exome sequencing to identify the causative mutation in two female siblings of a consanguineous Arab family showing some of the hallmark signs of a cerebellar-hypoplasia-related neurodevelopmental disorder. Direct Sanger sequencing was used to validate the candidate mutations that cosegregated with the phenotype. Gene expression and loss of function studies were carried out in the zebrafish model system to examine the role of the candidate gene in neurodevelopment. RESULTS: Patients presented with severe global developmental delay, intellectual disability, hypoplasia of the cerebellum and biochemical findings suggestive of nephrotic disease. Whole exome sequencing of the two patients revealed a shared nonsense homozygous variant in WDR73 (p.Q235X (c.703C>T)) resulting in loss of the last 144 amino acids of the protein. The variant segregated according to a recessive mode of inheritance in this family and was absent from public and our inhouse databases. We examined the developmental role of WDR73 using a loss-of-function paradigm in zebrafish. There was a significant brain growth and morphogenesis defect in wdr73 knockdown embryos resulting in a poorly differentiated midbrain and cerebellum. CONCLUSIONS: The results provide new insight into the functional role of WDR73 in brain development and show that perturbation of its function in an inherited disorder in humans is associated with cerebellar hypoplasia as well as nephrotic disease, consistent with Galloway-Mowat Syndrome.

High diagnostic yield of clinical exome sequencing in Middle Eastern patients with Mendelian disorders.

Clinical exome sequencing (CES) has become an increasingly popular diagnostic tool in patients with heterogeneous genetic disorders, especially in those with neurocognitive phenotypes. Utility of CES in consanguineous populations has not yet been determined on a large scale. A clinical cohort of 149 probands from Qatar with suspected Mendelian, mainly neurocognitive phenotypes, underwent CES from July 2012 to June 2014. Intellectual disability and global developmental delay were the most common clinical presentations but our cohort displayed other phenotypes, such as epilepsy, dysmorphism, microcephaly and other structural brain anomalies and autism. A pathogenic or likely pathogenic mutation, including pathogenic CNVs, was identified in 89 probands for a diagnostic yield of 60%. Consanguinity and positive family history predicted a higher diagnostic yield. In 5% (7/149) of cases, CES implicated novel candidate disease genes (MANF, GJA9, GLG1, COL15A1, SLC35F5, MAGE4, NEUROG1). CES uncovered two coexisting genetic disorders in 4% (6/149) and actionable incidental findings in 2% (3/149) of cases. Average time to diagnosis was reduced from 27 to 5 months. CES, which already has the highest diagnostic yield among all available diagnostic tools in the setting of Mendelian disorders, appears to be particularly helpful diagnostically in the highly consanguineous Middle Eastern population.

Molecular mechanism of WW-domain binding protein-2 coactivation function in estrogen receptor signaling.

The link between breast cancer and estrogen receptor (ER) is well established. The ER is a hormone-inducible transcription factor that, upon binding to its ligand, regulates the expression of a variety of genes mainly involved in cell proliferation and differentiation. Coactivators are proteins recruited by the hormone-activated receptor, which allow or enhance the ER transactivation functions by acting as chromatin remodeling enzymes or adaptors between ER and the transcriptional machinery. Our laboratory has previously identified the WW-domain binding protein-2 (WBP-2) as a bona fide coactivator of ER. However, the molecular mechanism underlying WBP-2 coactivation function was not clear yet. In this study, we explore and identify the mechanism by which WBP-2 acts as coactivator of ER. Our data show that WBP-2 is involved in the regulation of ER target genes, and its expression is required for the proper expression of some ER target genes. To clarify the molecular mechanism by which WBP-2 regulates ER function, we performed chromatin immunoprecipitation assays. We demonstrate here that WBP-2 binds to the ER target gene promoter pS2 promoter and is required for the binding of the phosphorylated form of RNA polymerase II (associated with active transcription/elongation) to the same promoter. Furthermore, we also show that WBP-2 is essential for the recruitment of the histone acetyl transferase p300, an important chromatin modifier enzyme and for histone acetylation at the same target region. Collectively, our data indicate that WBP-2 enhances ER transactivation function at certain genes by facilitating the recruitment and/or the stabilization of a histone modifier enzyme that favors a relaxed chromatin structure, permissive of transcription.

Spontaneous Remission in a Patient with Chronic Myeloid Leukemia: A Case Report.

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm in which granulocytic cells are the main proliferative component. At diagnosis, more than 90% of CML cases have the characteristic Philadelphia chromosome, containing the BCR::ABL1 fusion gene. The natural history of untreated CML is an initial indolent chronic phase which will be followed by an accelerated phase, blast phase, or both. Tyrosine kinase inhibitors (TKIs) have dramatically altered the natural history of CML. TKI discontinuation with the goal of treatment-free remission is currently part of current management recommendations. However, spontaneous remission without receiving any treatment is extraordinarily rare in CML patients. Herein, we report a 56-year-old male who presented with leukocytosis and was diagnosed as a case of CML in the chronic phase; however, treatment with TKIs was not initiated due to spontaneous hematological as well as molecular remission.

Label-free quantitative LC-MS proteomics of Alzheimer's disease and normally aged human brains.

Quantitative proteomics analysis of cortical samples of 10 Alzheimer's disease (AD) brains versus 10 normally aged brains was performed by following the accurate mass and time tag (AMT) approach with the high resolution LTQ Orbitrap mass spectrometer. More than 1400 proteins were identified and quantitated. A conservative approach of selecting only the consensus results of four normalization methods was suggested and used. A total of 197 proteins were shown to be significantly differentially abundant (p-values <0.05, corrected for multiplicity of testing) in AD versus control brain samples. Thirty-seven of these proteins were reported as differentially abundant or modified in AD in previous proteomics and transcriptomics publications. The rest to the best of our knowledge are new. Mapping of the discovered proteins with bioinformatic tools revealed significant enrichment with differentially abundant proteins of pathways and processes known to be important in AD, including signal transduction, regulation of protein phosphorylation, immune response, cytoskeleton organization, lipid metabolism, energy production, and cell death.

E3 ubiquitin protein ligase, E6-associated protein (E6-AP) regulates PI3K-Akt signaling and prostate cell growth.

This study elucidates the role of E6-associated protein, E6-AP (a dual function steroid hormone receptor coactivator and ubiquitin-protein ligase) in the regulation of PI3K-Akt signaling pathway, prostate gland growth and proliferation. Here, we report the generation of transgenic mice and prostate cancer cell line, LNCaP cells that overexpress E6-AP protein. Using these models we show that the levels of total Akt and phosphorylated Akt (active Akt) are increased in E6-AP overexpressing prostate gland and LNCaP cells suggesting that E6-AP regulates the PI3K-Akt signaling pathway. The prostate glands in our transgenic mice are ~20% larger and produce preneoplastic lesions at the age of 18 months. Our data also suggest that E6-AP modulates PI3K-Akt signaling pathway by both androgen-independent and -dependent mechanisms. In the androgen-independent mechanism, E6-AP modulates PI3K-Akt signaling by regulating the protein levels of RhoA, a small GTPase, which is a negative regulator of the Akt signaling pathway. Further, we show that E6-AP, a known coactivator of AR, amplifies the androgen-dependent activation of PI3K-Akt signaling pathway. In addition, we show that stable overexpression of E6-AP in prostate cancer cells results in increased cell size and proliferation. Overall our data suggests that E6-AP regulates both the positive and negative modulators of the PI3K-Akt pathway in prostate cells which results in increased prostate cell growth, proliferation and decreased apoptosis.This article is part of a Special Issue entitled The 26S Proteasome: When degradation is just not enough!