Review Reports - Effects of Glutathione Diminishment on the Immune Responses against <i>Mycobacterium tuberculosis</i> Infection

Round 1

Reviewer 1 Report

The authors aim to elucidate the effects of diethyl maleate (DEM)-induced GSH deficiency during an active M. tb infection in an in vivo mouse model. They assessed for total and reduced GSH levels, malondialdehyde (MDA) levels, cytokine profiles, granuloma formation and M. tb burden. After confirming that DEM administration significantly diminished total and reduced GSH levels in the lungs and plasma along with increased MDA levels in infected mice compared to sham-treated control mice. They found that DEM treatment was also associated with an increase in IL-6, TNF-α and ill-formed granulomas in infected mice. Furthermore, M. tb survival was significantly increased along with a higher pulmonary and extrapulmonary bacterial load following DEM treatment. Overall, GSH deficiency leads to increased oxidative stress, impaired granuloma response, and increased M. tb survival in infected mice. These findings can provide insight into how GSH-deficiency can interfere with the control of M. tb infection and avenues for novel therapeutic approaches.

This study was carried out properly and obtained results sound interesting. So, this manuscript could be acceptable without major revision. There are several points to be revised as follows.

(L.104) Please correct “C57BL6” to “C57BL/6” or “C57BL/6J”
In the experiments using tissue (lung, spleen etc.) lysate, the authors expressed the data as concentration in the tissue (for ex. µM total GSH in the lung tissue). In general, it should be expressed as mol/ tissue protein. Is it possible? If not, the author should state this matter.
(L.418) Please correct “TGF-B” to “TGF-β” or “TGF-beta”.
(L.445) Please correct “BAL/c” to “BALB/c” or “Balb/c”.

Author Response

REVIEWER 1:

We truly appreciate your comprehensive and thorough review of our paper. We have taken each comment to heart and to the best of our ability, made revisions to improve upon our original paper. We thank you for the feedback.

The authors aim to elucidate the effects of diethyl maleate (DEM)-induced GSH deficiency during an active M. tb infection in an in vivo mouse model. They assessed for total and reduced GSH levels, malondialdehyde (MDA) levels, cytokine profiles, granuloma formation and M. tb burden. After confirming that DEM administration significantly diminished total and reduced GSH levels in the lungs and plasma along with increased MDA levels in infected mice compared to sham-treated control mice. They found that DEM treatment was also associated with an increase in IL-6, TNF-α and ill-formed granulomas in infected mice. Furthermore, M. tb survival was significantly increased along with a higher pulmonary and extrapulmonary bacterial load following DEM treatment. Overall, GSH deficiency leads to increased oxidative stress, impaired granuloma response, and increased M. tb survival in infected mice. These findings can provide insight into how GSH-deficiency can interfere with the control of M. tb infection and avenues for novel therapeutic approaches.

This study was carried out properly and obtained results sound interesting. So, this manuscript could be acceptable without major revision. There are several points to be revised as follows.

(L.104) Please correct “C57BL6” to “C57BL/6” or “C57BL/6J”

Thank you, this has now been corrected.

In the experiments using tissue (lung, spleen etc.) lysate, the authors expressed the data as concentration in the tissue (for ex. µM total GSH in the lung tissue). In general, it should be expressed as mol/ tissue protein. Is it possible? If not, the author should state this matter.

Thank you, we have addressed this by changing our data to reflect micromoles/milligram protein in Figure 1 and 4 and also updating our results section to reflect this change.

(L.418) Please correct “TGF-B” to “TGF-β” or “TGF-beta”.

Thank you, this has now been corrected.

(L.445) Please correct “BAL/c” to “BALB/c” or “Balb/c”.

Thank you, this has now been corrected.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript by Can et al investigated the effects of GSH diminishment on the immune response against M. tb infections using a diethyl maleate (DEM)-induced GSH deficiency in a mouse lung model. The concept of exploration the effects of GSH level against M. tb infection is interesting, but the data presented in its current form was rather routine. The authors performed a few standard assays including the GSH assay, Il-6 and TNF-a, MDA assay and H&E staining. The data presentation was also rather dull. The connection between GSH deficiency and T2D was more of a speculation without any concrete data. Therefore, my suggestion would be to clarify what is the key contribution of this study and the data presentation should be significantly improved to reflect its significance.

Author Response

REVIEWER 2:

Agreed. The connection between GSH deficiency and T2D has been taken out of the majority of the paper to help focus on the effects of GSH deficiency and the relation to the immune response against M. tb.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Recommend publication after language check to eliminate typos and errors.

Author Response

09/02/2021

Dear Reviewer,

Thanks for the constructive feedback. Per your recommendation, we reviewed the manuscript numerous times to ensure that there are no typos or grammatical errors. The edits made are denoted in track changes. Once again, I appreciate your support and look forward to the publication of this important study.

Sincerely,

Vishwanath Venketaraman, Ph. D.

Professor
Microbiology/Immunology
Department of Basic Medical Sciences
College of Osteopathic Medicine of the Pacific
Western University of Health Sciences
309 E Second Street
Pomona, CA 91766-1854
Phone: 909-706-3736
Fax: 909-469-5698
Email: vvenketaraman@westernu.edu

Author Response File: Author Response.docx