Telomere length analysis from minimally-invasively collected samples: Methods development and meta-analysis of the validity of different sampling techniques: American Journal of Human Biology.

OBJECTIVES: Telomeres are the protective caps of chromosomes. They shorten with cell replication, age, and possibly environmental stimuli (eg, infection and stress). Short telomere length (TL) predicts subsequent worse health. Although venous whole blood (VWB) is most commonly used for TL measurement, other, more minimally invasive, sampling techniques are becoming increasingly common due to their field-friendliness, allowing for feasible measurement in low-resource contexts. We conducted statistical validation work for measuring TL in dried blood spots (DBS) and incorporated our results into a meta-analysis evaluating minimally invasive sampling techniques to measure TL. METHODS: We isolated DNA extracts from DBS using a modified extraction protocol and tested how they endured different shipping conditions and long-term cryostorage. We then included our in-house DBS TL validation statistics (correlation values with VWB TL and age) in a series of meta-analyses of results from 24 other studies that published similar associations for values between TL measured in DBS, saliva, and buccal cells. RESULTS: Our modified DBS extraction technique produced DNA yields that were roughly twice as large as previously recorded. Partially extracted DBS DNA was stable for 7 days at room temperature, and still provided reliable TL measurements, as determined by external validation statistics. In our meta-analysis, DBS TL had the highest external validity, followed by saliva, and then buccal cells-possibly reflecting similarities/differences in cellular composition vs VWB. CONCLUSIONS: DBS DNA is the best proxy for VWB from the three minimally-invasively specimen types evaluated and can be used to expand TL research to diverse settings and populations.

Quantification and real-time tracking of RNA in live cells using Sticky-flares.

We report a novel spherical nucleic acid (SNA) gold nanoparticle conjugate, termed the Sticky-flare, which enables facile quantification of RNA expression in live cells and spatiotemporal analysis of RNA transport and localization. The Sticky-flare is capable of entering live cells without the need for transfection agents and recognizing target RNA transcripts in a sequence-specific manner. On recognition, the Sticky-flare transfers a fluorophore-conjugated reporter to the transcript, resulting in a turning on of fluorescence in a quantifiable manner and the fluorescent labeling of targeted transcripts. The latter allows the RNA to be tracked via fluorescence microscopy as it is transported throughout the cell. We use this novel nanoconjugate to analyze the expression level and spatial distribution of ß-actin mRNA in HeLa cells and to observe the real-time transport of ß-actin mRNA in mouse embryonic fibroblasts. Furthermore, we investigate the application of Sticky-flares for tracking transcripts that undergo more extensive compartmentalization by fluorophore-labeling U1 small nuclear RNA and observing its distribution in the nucleus of live cells.