Improvement in Facial Wrinkles Using Materials Enhancing PPARGC1B Expression Related to Mitochondrial Function

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript entitled "Improvement of Facial Wrinkles using Materials that Enhance PPARGC1B Expression related to Mitochondrial Function" shows the role of the PGC-1β transcription factor in the regulation of dermal extracellular matrix and proposes the use of several compounds that up-regulate PGC-1β against UVB-induced photodamage. The study is well-designed, starting from studies on human skin fibroblasts and using also a reconstructed three-dimensional human skin model and a small-scale clinical trial on human volunteers. The manuscript is also well-written with clear aims and substantiated figures and results.

The authors should correct the reference number in line 87 (ref. 22 has nothing to do with genome-wide association analysis).

Comments on the Quality of English Language

The manuscript language is fine.

Author Response

Response to Reviewer 1 Comments

1. Summary
   Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions highlighted/in track changes in the re-submitted files.
   
   
2. Point-by-point response to Comments and Suggestions for Authors
   

   Comments 1:

   The manuscript entitled "Improvement of Facial Wrinkles using Materials that Enhance PPARGC1B Expression related to Mitochondrial Function" shows the role of the PGC-1β transcription factor in the regulation of dermal extracellular matrix and proposes the use of several compounds that up-regulate PGC-1β against UVB-induced photodamage. The study is well-designed, starting from studies on human skin fibroblasts and using also a reconstructed three-dimensional human skin model and a small-scale clinical trial on human volunteers. The manuscript is also well-written with clear aims and substantiated figures and results.

   The authors should correct the reference number in line 87 (ref. 22 has nothing to do with genome-wide association analysis).
   
   

   Response 1: Thank you for pointing this out. We correct the mentioned reference in line 87, by adding missed reference containing genome wide association analysis.

   “23. Lee, S-G.; Shin J-G.; Kim, Y.; Leem, S.; Park, S.-G.; Won, H-H.; Kang, N.G. Identification of Genetic Loci Associated with Facial Wrinkles in a Large Korean Population. J Invest Dermatol. 2022, 142(10):2824-2827, doi: 10.1016/j.jid.2022.03.027.” 

Reviewer 2 Report

Comments and Suggestions for Authors

In this study the authors screened a number of bioactive materials from a library of suitable cosmetic ingredients with the aim to identify PPARGC1B inducers in order to use them in a cream formulation with antiaging properties.

1. Experimental design is not clear: Did the authors screen more bioactive compounds to results with the five that were the only ones inducing PPARGC1B overexpression? Please elaborate. How were the compounds to be tested were initially selected?

2. In the siRNA experiments, did not the authors use a scramble sequence to warrant the absence of non-specific knock-down events?

3. The authors should perform a western blot analysis to show siRNA-mediated knocking-down at the protein level, especially given that presented loss-of-expression at the mRNA level is lower than 70%.

4. The effect of the tested compounds only on PPARGC1B expression is shown. The authors should also check expression levels of the genes tested in Fig. 1C in the presence of the tested compounds.

5. Most importantly, why did the authors incorporate all five materials in the cream? An experiment for the assessment of a putative additive effect (using the in vitro assays presented in the study) should precede cream formulation preparation. If materials do not have an additive effect, a less complicated cream formulation (containing one or two ingredients) could be prepared.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Moderate editing of English language required

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Introduction:

lines 32-36: this phrase is too sexist. Please consider to exclude it. Is this the only relation between women and ageing? Are they not interested to ageing in a healthier way?

What is the definition of materials for the authors? It seems that we are talking about ingredients or combination of materials. I strongly suggest to review the term materials accross the paper.

Material and method

UV irradiation: please provide more information regarding intensity, time of exposure, distance of exposure etc.

How much formulation was applied in each test? How long it was in contact with the cell cultures and skin models? Please calculate the amount of substance was applied in each test according to the percentual in the creams.

Did the authors always applied creams with the substances or just a mixture? Please provide more information. If a cream was applied, please add some information regarding the formulation (it is presented only in the clinical study, is it the same?)

Results

Figure 2

Do the authors have a control to compare? What means, the knockout without the application of the substances. If yes, please include in this image, it is a little bit confuse to understand what your statistics are showing (it seems some increase but I can not trust in a statistic without SD, distribuctions etc).

I also recommend the authors to use box plot instead of this type of graphic. Information is missing.

Figure 6

I am a little confused regarding the images from the skin model. The dermis seems to be thicker, but the epidermis is thinner. Is this a real bennefit? Epidermis is an effective barrier and I assume that a thinner epidermis is not a positive effect for a cream. Please provide the evaluation of epidermis thickness. Why is this happening? Retinol normally is a molecule which increases the epidermal thickness (and reduces the SC thickness, but improve its conformation).

The effects observed at your clinical studies can be related with skin hydration. Why the authors did not include an evaluation of skin hydration or TEWL at your study?

General questions

Ok, you have a mix of substances that can act at fibroblasts and improve the collagen production etc. However, cosmetics should not penetrate too deep - and skin is a very cohesive barrier. How can you explain that your clinical studies are not just a skin hydration effect? Without a penetration study it is difficult to comprehend the extention of your results.Why the authors did not utilize keratinocytes?

Another point is that you do not have a negative control on your study, so we do not know the contribuction from your vehicle.

Why do not use retinol at 0.3%, normally this is the maximal in cosmetic legislation and the skin care products are developed with this amount. 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

This is the revised version of a previously submitted manuscript. The authors have replied to most of my queries.

Comments on the Quality of English Language

The manuscript still contains some grammar and syntax errors that need to be corrected. The authors need to check the manuscript throughout.

Author Response

Thank you for your comments.

We thoroughly reviewed and revised the manuscript with the help of Editage, a professional proofreading agency.

Author Response File: Author Response.pdf