Biology subjects

Muth, D. C.

Publications and source records attributed to Muth, D. C..

3 recordsLinked to original sources

bioRxiv2018

miRNAs in platelet-poor blood plasma and purified RNA are highly stable: a confirmatory study

The relative stability of microRNAs (miRNAs) as compared with other RNA molecules has been confirmed in many contexts. When bound to Argonaute (AGO) proteins, miRNAs are protected from degradation, even when released into the extracellular space in ribonucleoprotein complexes, and with or without the protection of membranes in extracellular vesicles (EVs). Purified miRNAs also appear to present less of a target for degradation than other RNAs. Although miRNAs are by no means immune to degradation, biological samples subjected to prolonged incubation at room temperature, multiple freeze/thaws, or collection in the presence of inhibitors like heparin, can typically be remediated or used directly for miRNA measurements. Here, we provide additional confirmation of early, well validated findings on miRNA stability and detectability. Our data also suggest that inadequate depletion of platelets from plasma may explain the occasional report that freeze-thaw cycles can adversely affect plasma miRNA levels. Overall, the repeated observation of miRNA stability is again confirmed.

molecular biology↗

bioRxiv2018

miRNA profiling of primate cervicovaginal lavage and extracellular vesicles reveals miR-186-5p as a potential retroviral restriction factor in macrophages

The goal of this study was to characterize extracellular vesicles (EVs) and miRNAs of primate cervicovaginal lavage (CVL) during the menstrual cycle and simian immunodeficiency virus (SIV) infection, and to determine if differentially regulated CVL miRNAs might influence retrovirus replication. CVL and peripheral blood were collected from SIV-infected and uninfected macaques. EVs were enriched by stepped ultracentrifugation and characterized thoroughly. miRNA profiles were assessed with a medium-throughput stem-loop/hydrolysis probe qPCR platform and validated by single qPCR assays. Hormone cycling was abnormal in infected subjects, but EV concentration correlated with progesterone concentration in uninfected subjects. miRNAs were present predominantly in the EV-depleted CVL supernatant. Only a small number of CVL miRNAs were found to vary during the menstrual cycle or SIV infection. Among them was miR-186-5p, which was depleted in retroviral infection. In experiments with infected macrophages in vitro, this miRNA inhibited HIV replication. These results provide further evidence for the potential of EVs and small RNAs as biomarkers or effectors of disease processes in the reproductive tract.

molecular biology↗

bioRxiv2016

Serum extracellular vesicle depletion processes affect release and infectivity of HIV-1 in culture

Extracellular vesicles (EVs, including exosomes and microvesicles) are involved in intercellular communication in health and disease and affect processes including immune and antiviral responses. Ultracentrifuged serum is depleted of EVs and, when used in culture media, reduces growth and viability of some cell types. In this study, we examined the effects of serum EV depletion processes on HIV-1 replication in primary cells and cell lines, including two HIV-1 latency models. Increased HIV-1 production was observed in certain EV-depleted conditions, along with cell morphology changes and decreased cell viability. Add-back of ultracentrifuge pellets rescued baseline HIV-1 production. Primary cells appeared to be less sensitive to EV depletion. ACH-2 and U1 latency models produced more HIV-1 under EV-depleted conditions, while virus produced under processed serum conditions was more infectious. Finally, changes in cellular metabolism and gene expression were associated with EV-depleted culture. In conclusion, the EV environment of HIV-1 infected cells has a substantial effect on virus production and infectivity. EV-dependence of cell cultures should be examined carefully along with other experimental variables. However, EVs may not be the only particles depleted by ultracentrifugation or other processes. Effects of EVs may be accompanied by or confused with those of closely associated or physically similar particles.

molecular biology↗