Aim: Mesenchymal stromal cells (MSCs) emerged as a promising therapeutic option for osteoarthritis (OA) management, in particular those isolated from adipose tissue (hASCs) and amniotic membrane (hAMSCs). The cartilage protective and immunomodulatory features of hASCs and hAMSCs are ascribed to secreted factors, including extracellular vesicles (EVs) and embedded miRNAs. The purpose of this study was to compare EVs and shuttled miRNAs from both MSC types and discuss them in the frame of OA pathological tissues.
Methods: Human hASCs and hAMSCs were analyzed by flow cytometry. EVs were analyzed by flow cytometry, nanoparticle tracking analysis, and electron microscopy. High-throughput qRT-PCR miRNA data available in the literature were compared. Abundant miRNAs and their experimentally validated targets were associated with those reported to drive OA pathology at cartilage, synovia, and macrophage levels. Four tools (Genorm, Normfinder, BestKeeper, and Delta Ct) were used to identify EVs stable reference genes.
Results: EVs did not show phenotypical or dimensional differences between the two sources, with hAMSCs releasing more particles. In total, 307 EV miRNAs were identified, with 306 shared. Several of the most abundant miRNAs target OA-driving factors and are involved in cartilage and synovia protective mechanisms, with hAMSC-EVs’ preponderance for M2 anti-inflammatory macrophage commitment. miR-34a-5p emerged as the most stable reference gene.
Conclusion: Both hASCs and hAMSCs release EVs enriched in joint-protective and anti-inflammatory miRNAs, supporting their use for treatment of joint diseases. Future comparative clinical studies would be needed to test whether hAMSCs’ higher EV secretion and enhanced M2 macrophage polarizing miRNA cargo allow for potentially increased OA therapeutic features.
Many researchers worldwide are currently trying to develop targeted molecular therapies such as nucleic acid medicines or antibody-drug conjugates for various diseases. Writing in Extracellular Vesicles and Circulating Nucleic Acids, Kim et al. summarized existing technologies for encapsulating therapeutic molecules into exosomes and introduced some human cell lines which are able to produce safe, effective therapeutic exosomes. Their review article offers the “magic bullet” for fighting threats to humanity such as the current coronavirus pandemic.
Aim: The fragmentation characteristics of cell-free DNA (cfDNA) are informative biomarkers in liquid biopsies, including non-invasive prenatal testing (NIPT), as they provide insights into the origins of the cfDNA. Viral infections by DNA viruses can contribute to the available cfDNA in these samples. Here, we characterize the fragment size distribution of viral cfDNA fragments obtained from available anonymous NIPT samples.
Methods: A viral database of 224 DNA viruses was generated from the NCBI RefSeq viral database. Paired-end cfDNA sequencing reads from 83.522 NIPT samples that did not map to any of the human chromosomes, or mitochondrial DNA of the human reference genome build GRCh38 (excluding alternative and unplaced contigs) were remapped to the generated viral database. Reads mapping to the 14 most abundant DNA viruses were selected, and fragment size distributions were analyzed in detail.
Results: Distinct fragmentation patterns were identified for several DNA viruses, most likely due to differences in viral tropism, chromatinization (binding of nucleosomes), and the topology of the viral DNA. In high viral load parvo B19 positive samples, the fragment size distribution differed between samples, potentially reflecting the state of the infection.
Conclusion: These findings outline the potential for liquid biopsies to elucidate the dynamics behind the viral infection, which may potentially have various clinical applications. Our data provide preliminary insights on the use of fragmentomics of viral cfDNA to distinguish between reactivation, reinfection, and primary infection and monitoring the state of viral infections.