Genome-wide association study for systemic lupus erythematosus in an egyptian population

Systemic lupus erythematosus (SLE) susceptibility has a strong genetic component. Genome-wide association studies (GWAS) across trans-ancestral populations show both common and distinct genetic variants of susceptibility across European and Asian ancestries, while many other ethnic populations remain underexplored. We conducted the first SLE GWAS on Egyptians-an admixed North African/Middle Eastern population-using 537 patients and 883 controls. To identify novel susceptibility loci and replicate previously known loci, we performed imputation-based association analysis with 6,382,276 SNPs while accounting for individual admixture. We validated the association analysis using adaptive permutation tests (n = 109). We identified a novel genome-wide significant locus near IRS1/miR-5702 (Pcorrected = 1.98 × 10-8) and eight novel suggestive loci (Pcorrected < 1.0 × 10-5). We also replicated (Pperm < 0.01) 97 previously known loci with at least one associated nearby SNP, with ITGAM, DEF6-PPARD and IRF5 the top three replicated loci. SNPs correlated (r 2 > 0.8) with lead SNPs from four suggestive loci (ARMC9, DIAPH3, IFLDT1, and ENTPD3) were associated with differential gene expression (3.5 × 10-95 < p < 1.0 × 10-2) across diverse tissues. These loci are involved in cellular proliferation and invasion-pathways prominent in lupus and nephritis. Our study highlights the utility of GWAS in an admixed Egyptian population for delineating new genetic associations and for understanding SLE pathogenesis.

High Temperature Drives Topoisomerase Mediated Chromosomal Break Repair Pathway Choice

Simple Summary

Targeting topoisomerases has been widely used as anticancer therapeutics. Exposure to high temperature (hyperthermia) protects cells from the cytotoxic effect of topoisomerase-targeting therapeutics, yet the mechanism remains unknown. Here, we report that hyperthermia inhibits the nucleolytic processing of topoisomerase-induced DNA damage and drives repair to a more faithful pathway mediated by TDP1 and TDP2. We further show that hyperthermia suppresses topoisomerase-induced chromosomal translocation and hallmarks of inflammation, which has broad implications in cancer development and therapy.

Abstract

Cancer-causing mutations often arise from inappropriate DNA repair, yet acute exposure to DNA damage is widely used to treat cancer. The challenge remains in how to specifically induce excessive DNA damage in cancer cells while minimizing the undesirable effects of genomic instability in noncancerous cells. One approach is the acute exposure to hyperthermia, which suppresses DNA repair and synergizes with radiotherapy and chemotherapy. An exception, however, is the protective effect of hyperthermia on topoisomerase targeting therapeutics. The molecular explanation for this conundrum remains unclear. Here, we show that hyperthermia suppresses the level of topoisomerase mediated single- and double-strand breaks induced by exposure to topoisomerase poisons. We further uncover that, hyperthermia suppresses hallmarks of genomic instability induced by topoisomerase targeting therapeutics by inhibiting nuclease activities, thereby channeling repair to error-free pathways driven by tyrosyl-DNA phosphodiesterases. These findings provide an explanation for the protective effect of hyperthermia from topoisomerase-induced DNA damage and may help to explain the inverse relationship between cancer incidence and temperature. They also pave the way for the use of controlled heat as a therapeutic adjunct to topoisomerase targeting therapeutics.

Gold aggregating gold: A novel nanoparticle biosensor approach for the direct quantification of hepatitis C virus RNA in clinical samples

The affordable and reliable detection of Hepatitis C Virus (HCV) RNA is a cornerstone in the management and control of infection, affecting approximately 3% of the global population. However, the existing technologies are expensive, labor intensive and time consuming, posing significant limitations to their wide-scale exploitation, particularly in economically deprived populations. Here, we utilized the unique optical and physicochemical properties of gold nanoparticles (AuNPs) to develop a novel assay platform shown to be rapid and robust in sensing and quantifying unamplified HCV RNA in clinical samples. The assay is based on inducing aggregation of citrate AuNPs decorated with a specific nucleic acid probe. Two types of cationic AuNPs, cysteamine and CTAB capped, were compared to achieve maximum assay performance. The technology is simple, rapid, cost effective and quantitative with 93.3% sensitivity, high specificity and detection limit of 4.57IU/µl. Finally, our data suggest that RNA folding impact the aggregation behavior of the functionalized AuNPs, with broader applications in other nucleic acid detection technologies.

Primary nasopharyngeal non Hodgkin lymphoma: A retrospective investigation of 26 patients

e19552

Background: Primary nasopharyngeal non-Hodgkin lymphoma (NNHL) was uncommon. In this retrospective study we report our experience dealing with this disease at the National Institute of Oncology. Methods: We retrospectively analyzed various characteristics of Primary NNHL: patient demographics, clinical and histological diagnosis, disease stage, treatment effects and outcome, in 26 patients treated at our institution between January 2001 and December 2007. Results: The average age of our patients was 52.7 years (range: 31 - 87 years). The male/female ratio was equal to 1.5/1. The major symptoms at first diagnosis were: nasal obstruction (88.6%), hypoacousia (88.4%), epistaxis (33.3%) and rhinorrhea (15.3%). Clinical examination founded bilateral cervical lymph nodes in 17 cases (65%). Histological analysis showed follicular lymphoma in 7 cases (26.9%), large B-cell lymphoma in 11 cases (42,3%) and T lymphoma in 4 cases ( 15,3%). Four (15.4%) of the patients were at stage I, 15 (57.6%) were at stage II, and 7 (27%) were at stage III/IV. At early stage, the patients were managed with chemo-radiotherapy and were managed with CHOP based chemotherapy at advanced stage. At the end of total treatment, 18 patients (69.2%) achieved complete response and remained disease free while 4 (15.4%) achieved partial response (>70%) and 4 (15.4%) were progressive (these patients received second line chemotherapy). After 110 months median flow-up, median disease free and overall survival were not reached. Overall, the treatment was well tolerated. Conclusions: From our study and from the literature, we conclude that histological characteristics, principle of treatment and outcome of primary NNHL patients are similar to that of patients with nodal lymphoma.

No significant financial relationships to disclose.