Peer-reviewed by 3 reviewers with median rating of 11.5/20. Review process was triple-blinded.
Round 1 (11.5/20)
Round 2 (11.5/20)
Conceptual advance and Impact8
The authors should include a more detailed EV isolation procedure, so the reader can exclude the possibility of apoptotic vesicle isolation.
Conceptual advance and Impact1.5
The title suggests a biological response to stimulus, such as the release of histamine. However, the mast cells were not stimulated in this experiment. Perhaps a better title would be "Conditioned medium from human mast cells contains DNA of different molecular weights that can adhere to cells."
No conclusions described.
No conjectures described.
There is not a list of references and the manuscript does not contain direct links to Pubmed.
It's not clear to the reader whether the methodology described is sufficient for the objective. Unsure if the differential centrifugation can isolate extracellular vesicles containing DNA from uncontrolled lipoprotein aggregates containing genomic DNA. A control group could include a purified DNA fraction without EVs that may not enter mesenchymal cells.
Results & Discussion
Several technical problems with the experiment limit the ability of the reader to make meaningful interpretations.
The multiple bands of DNA in the gels are similar to observations of DNA from apoptotic cells. Such isolated genomic DNA aggregates easily and may be attached to a variety of cellular debris, including EVs.
Missing experimental control groups. A comparison of stimulated versus unstimulated mast cells (control group) would provide a biological context for the data. Another control group of purified genomic DNA fragments without EVs would help to clarify the presence and function of the EVs in this experiment.
The assay for cellular uptake of DNA is not robust. The images of mesenchymal cells in panel D may show either adherence of the DNA to the plasma membrane or uptake of the DNA. The authors need to demonstrate that the fractionated DNA has crossed the plasma membrane to be sure that cellular uptake has taken place.
No limitations described.
The method does not contain sufficient information to allow the reader to conclude that exosomes were isolated from the culture of HMC1.2 cells.
Conceptual advance and Impact8.5
This study is an excellent single observation study describing the presence of DNA on the outer surface of EVs and how this confers net increase in the negative charge. This is truly a fantastic observations.
If this were to be demonstrated in one more cell line, that would have made this more compelling.
The authors should say: "In conclusion, we report that DNA is present on EVs and speculate that this might regulate recipient cellular function"