Review for 10.1186/s12876-017-0731-5 (2018)

Reviewer ’s report  
 
Title: Cobalt Chloride Compromises Transepithelial Barrier Properties of CaCo -2 BBe Human 
Gastrointestinal Epithelial Cell Layers  
 
Version: 0 Date: 01 Feb 2017  
 
Reviewer: Radhakrishna  Rao 
 
Reviewer's report:  
 
Authors in this study have evaluated the effect of CoCl2 on the barrier function of Caco -2 cell 
monolayers.  The study indicates that CoCl2 treatment reduces resistance and increases 
macrom olecular permeability.  Study provides evidence to the role of HIF in this effect of 
CoCl2.  This is an interesting study, but poorly presented manuscript. It requires rearranging 
some of the data, and clarifying few specific issues.  
 
 
 
1. Fig 1: The inset on  HIF1α blot seems to be out of place and certainly does not belong in 
this figure.  
 
 
2. The Y -axis label indicates that these are immunoblot density.  Figure legend needs to be 
expanded to provide all details.  Also, show the representative blots for these t hree 
proteins.  
 
 
3. Discuss the significance of increased levels of claudins.  
 
 
4. Discuss the significance of basolateral effect.  
 
 
5. Figure 4: it is out of place.  It should be either part of or replace figure 1.  
 
 
6. Fig. 6: The HIF1a blot from figure 1 probab ly should be in this figure.   
 
 
7. Best way to determine whether HIF1α is involved in CoCl2 effect is to knockdown 
HIF1α by RNAi.  
 
 
8. Fig. 7: this figure is should be figure 2 or 3.  
 
9. Fig. 8: Is HIF1a expression in response to CoCl2 is high in 3D cell monol ayers compared 
to that in 7D cell monolayers?  
 
 
10. HIF knockdown study: a) Figure one shows immunoblot for HIF1α, but here HIF1β is 
knocked down.  Why switch from HIF1a to HIF1β? b) It is important to show data from 
control and CoCl2 -treated cell monolayers .  c) Label the blot for different samples. d) 
HIFβ knockdown appears to be almost complete.  Discuss why its effects on resistance 
and flux are only partial.  
 
 
 
 
Are the methods appropriate and well described?  
If not,  please specify what is required in your comments to the authors.  
 
Yes 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequatel y supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any statistics in the manuscript or wo uld you recommend an 
additional statistical review?  
If an additional statistical review is recommend ed, please specify what aspects require further 
assessment in your comments to the editors.  
 
I am able to assess the statistics  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Needs some language corrections before being published  
 
 
 
 
 
 
 
Are the methods appropriate and well described?  
If not, please specify what is required i n your comments to the authors.  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an 
organisation that may in any way ga in or lose financially from the publication of this 
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose 
financially from the publication of this manuscript, either now or in the  future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the 
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds or has applied for patents relating to the co ntent of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing inter ests' 
below. If your reply is yes to any, please give details below.  
 
I declare tha tI have no competing interests.  
 
I agree to the open peer review policy of the journal. I understand t hat my name will be included 
on my report to the authors and, if the m anuscript is accepted f or publication, my named report 
including any attachments I upload will be posted on the website along  with the authors' 
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CC-BY license (http://creativecommons.org/licenses/by/4.0/ ). I understand that a ny comments 
which I do not wish to be included in my named report can be included as confidential  comments 
to the editors, which will not be published.  
 
I agree to the open peer review policy of t he journal