Search results for "Reverse transcriptase"

Physicochemical and Preclinical Evaluation of Spermine-Derived Surfactant Liposomes for in Vitro and in Vivo siRNA-Delivery to Liver Macrophages

2016

Herein we report on a liposomal system for siRNA delivery consisting of cholesterol (Chol), distearoylphosphatidylcholine (DSPC), and surfactant TF (1-hydroxy-50-amino-3,4,7,10,13,16,19,22-octaoxa-37,41,45-triaza-pentacontane), a novel spermine derivative (HO-EG8-C12-spermine) which has shown improved siRNA delivery to cells in vitro and in vivo. Predominantly single-walled liposomes with reproducible sizes and moderately broad size distributions were generated with an automated extrusion device. The liposomes remained stable when prepared in the presence of siRNA at N/P ratios of 17-34. However, when mixed with human serum in equal volumes, larger aggregates in the size range of several hu…

DNA demethylation caused By 5-Aza-2'-Deoxycytidine induces mitotic alterations and aneuploidy

2016

Aneuploidy, the unbalanced number of chromosomes in a cell, is considered a prevalent form of genetic instability and is largely acknowledged as a condition implicated in tumorigenesis. Epigenetic alterations like DNA hypomethylation have been correlated with cancer initiation/progression. Furthermore, a growing body of evidence suggests the involvement of epigenome-wide disruption as a cause of global DNA hypomethylation in aneuploidy generation. Here, we report that the DNA hypomethylating drug 5-aza-2′-deoxycytidine (DAC), affects the correct ploidy of nearly diploid HCT-116 human cells by altering the methylation pattern of the chromosomes. Specifically, we show that a DAC-induced reduc…

Virus-encoded microRNA contributes to the molecular profile of EBV-positive Burkitt lymphomas

2015

Burkitt lymphoma (BL) is an aggressive neoplasm characterized by consistent morphology and phenotype, typical clinical behavior and distinctive molecular profile. The latter is mostly driven by the MYC over-expression associated with the characteristic translocation (8;14) (q24; q32) or with variant lesions. Additional genetic events can contribute to Burkitt Lymphoma pathobiology and retain clinical significance. A pathogenetic role for Epstein-Barr virus infection in Burkitt lymphomagenesis has been suggested; however, the exact function of the virus is largely unknown. In this study, we investigated the molecular profiles (genes and microRNAs) of Epstein-Barr virus-positive and -negative…

Haploinsufficiency of the Primary Familial Brain Calcification Gene SLC20A2 Mediated by Disruption of a Regulatory Element

2020

OBJECTIVE Primary familial brain calcification (PFBC) is a rare cerebral microvascular calcifying disorder with diverse neuropsychiatric expression. Five genes were reported as PFBC causative when carrying pathogenic variants. Haploinsufficiency of SLC20A2, which encodes an inorganic phosphate importer, is a major cause of autosomal-dominant PFBC. However, PFBC remains genetically unexplained in a proportion of patients, suggesting the existence of additional genes or cryptic mutations. We analyzed exome sequencing data of 71 unrelated, genetically unexplained PFBC patients with the aim to detect copy number variations that may disrupt the expression of core PFBC-causing genes. METHODS Afte…

Extracellular Vesicles Shed by Melanoma Cells Contain a Modified Form of H1.0 Linker Histone and H1.0 mRNA-binding Proteins

2016

Extracellular vesicles (EVs) are shed in the extracellular environment by both prokaryotes and eukaryotes. Although produced from both normal and cancer cells, malignant cells release a much higher amount of EVs, which also contain tumor-specific proteins and RNAs. We previously found that G26/24 oligodendroglioma cells shed EVs that contain the pro-apoptotic factors FasL and TRAIL1-2. Interestingly, G26/24 release, via EVs, extracellular matrix remodelling proteases3, and H1° histone protein4, and mRNA. To shed further light on the role of EVs in discarding proteins and mRNAs otherwise able to counteract proliferative signals, we studied a melanoma cell line (A375). We found that also thes…

Mitophagy in human astrocytes treated with the antiretroviral drug Efavirenz: Lack of evidence or evidence of the lack

2019

Efavirenz (EFV), a first generation non-nucleoside analogue reverse transcriptase inhibitor widely employed in combination antiretroviral therapy regimens over the last 20 years, has been associated with a wide range of neuropsychiatric effects and has also been linked with HIV-associated neurocognitive disorder (HAND). EFV has been reported to alter mitochondrial dysfunction and bioenergetics in different cell types, including astrocytes. Here, we analyzed whether this mitochondrial effect is associated with alterations in autophagy and, more specifically, mitophagy. U251-MG cells were exposed to EFV (10 and 25 μM; 24 h) and the effect was compared with that of CCCP - an uncoupler of the m…

2019

Recent studies on extracellular RNA raised awareness that extracellular vesicles (EVs) isolated from cultured cells may co-purify RNAs derived from media supplements such as fetal bovine serum (FBS) confounding EV-associated RNA. Defined culture media supplemented with a range of nutrient components provide an alternative to FBS addition and allow EV-collection under full medium conditions avoiding starvation and cell stress during the collection period. However, the potential contribution of serum-free media supplements to EV-RNA contamination has remained elusive and has never been assessed. Here, we report that RNA isolated from EVs harvested from cells under serum-replacement conditions…

Externalized decondensed neutrophil chromatin occludes pancreatic ducts and drives pancreatitis

2016

Ductal occlusion has been postulated to precipitate focal pancreatic inflammation, while the nature of the primary occluding agents has remained elusive. Neutrophils make use of histone citrullination by peptidyl arginine deiminase-4 (PADI4) in contact to particulate agents to extrude decondensed chromatin as neutrophil extracellular traps (NETs). In high cellular density, NETs form macroscopically visible aggregates. Here we show that such aggregates form inside pancreatic ducts in humans and mice occluding pancreatic ducts and thereby driving pancreatic inflammation. Experimental models indicate that PADI4 is critical for intraductal aggregate formation and that PADI4-deficiency abrogates…

Apoptosis induced by a HIPK2 full-length-specific siRNA is due to off-target effects rather than prevalence of HIPK2-Δe8 isoform

2017

Small interfering RNAs (siRNAs) are widely used to study gene function and extensively exploited for their potential therapeutic applications. HIPK2 is an evolutionary conserved kinase that binds and phosphorylates several proteins directly or indirectly related to apoptosis. Recently, an alternatively spliced isoform skipping 81 nucleotides of exon 8 (Hipk2-Δe8) has been described. Selective depletion of Hipk2 full-length (Hipk2-FL) with a specific siRNA that spares the Hipk2-Δe8 isoform has been shown to strongly induce apoptosis, suggesting an unpredicted dominant-negative effect of Hipk2-FL over the Δe8 isoform. From this observation, we sought to take advantage and assessed the therape…

ICTV Virus Taxonomy Profile: Pseudoviridae

2021

Pseudoviridae is a family of reverse-transcribing viruses with long terminal repeats (LTRs) belonging to the order Ortervirales. Pseudoviruses are commonly found integrated in the genomes of diverse plants, fungi and animals and are broadly known as Ty1/Copia LTR retrotransposons. Inside the cell, they form icosahedral virus particles, but unlike most other viruses, do not have an extracellular phase. This is a summary of the ICTV Report on the family Pseudoviridae, which is available at ictv.global/report/pseudoviridae.