Cationic Porphyrins as Antimicrobial and Antiviral Agents in Photodynamic Therapy

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you very much for submitting your interesting manuscript to CIMB. As a reviewer, I have the following comments on this study:

[Major comments]

1. In your current manuscript, the authors should investigate the alternatives to the current therapy. What are the advantages and disadvantages in the fields of bioindustry and/or medical sciences? Please describe them.

2. The current therapy is a little bit old and classical in the field. What is the reason that there are no specific drugs derived from photodynamic therapy? And then other approaches can be described in detail and explained as to how to overcome them.

 

 

Comments on the Quality of English Language

Thank you very much for submitting your interesting manuscript to CIMB. As a reviewer, I have the following comments on this study:

[Major comments]

1. In your current manuscript, the authors should investigate the alternatives to the current therapy. What are the advantages and disadvantages in the fields of bioindustry and/or medical sciences? Please describe them.

2. The current therapy is a little bit old and classical in the field. What is the reason that there are no specific drugs derived from photodynamic therapy? And then other approaches can be described in detail and explained as to how to overcome them.

 

 

Author Response

Thank you very much for your comments. We carefully read your review and corrected the manuscript’s text:

1. In your current manuscript, the authors should investigate the alternatives to the current therapy. What are the advantages and disadvantages in the fields of bioindustry and/or medical sciences? Please describe them.

Answer: The following text was added in the introduction. It devoted to the alternatives to the current therapy:

Antibiotics and antivirals are the most extensively used chemotherapeutical treatment of infectious diseases. Fast rate of bacteria or viruses’ mutation helps them to survive and receive resistance to the current drugs. Developing of new antibacterial or antiviral drugs is the most common strategy to overcome drug resistance. The widespread use of antibiotic drugs has led to the emergence of so-called "superbacteria", which are resistant to virtually all types of antibiotics. The major mechanisms of drug resistance include reducing drug internalization, overexpressing drug efflux pumps, sequestering entered drugs, modifying drug targets, as well as the formation of biofilms [http://dx.doi.org/10.1016/j.micpath.2016.02.009; https://doi.org/10.1016/S1473-3099(17)30753-3; http://dx.doi.org/10.1101/cshperspect.a026989; https://doi.org/10.1016/j.addr.2021.113941]. At the same time, administration of antibiotics leads to a number of undesirable side effects: negative impact on the normal microflora of the organism, nephro-, oto-, neurotoxic and other effects. In addition, some classes of antibiotics, for example, glycopeptide have a pseudoallergic effect - the so-called "red face syndrome" due to the release of histamine from mast cells.

Currently, alternative to traditional antibiotic therapy approaches were developed. Such approaches include the use of immunobiological drugs (vaccines, antibodies, probiotics, immunostimulants), biological defense agents (bacteriophages, phagolysins, artificial bacteriophages), as well as new chemotherapeutic agents based on peptides (antimicrobial peptides), antibacterial nucleic acids, antibiofilm compounds and some others [https://doi.org/10.1016/B978-0-323-89837-9.00004-8; https://doi.org/10.1016/j.bioactmat.2020.12.027; https://doi.org/10.1016/j.bioadv.2023.213684; https://doi.org/10.1016/j.sjbs.2021.08.054]. Despite a wide variety of new alternative approaches, there have been no striking breakthroughs in the treatment of infections using them for more than a decade [10.24075/brsmu.2018.002]. Many of the new methods are at the experimental research stage or even developed only theoretically [http://dx.doi.org/10.1016/S1473-3099(15)00466-1]. Phage therapy is considered as the one of the most promising methods in terms of clinical potential and ease of use [https://doi.org/10.1016/j.micpath.2023.106199]. Nevertheless, the appearance on the market of ready-to-use drugs to replace antibiotics is still questionable. The significance of immunostimulants, which are already used for disease prevention and as additional means of therapy, for clinical practice is unclear, so they do not look like a full-fledged substitute for antibiotics.

2. The current therapy is a little bit old and classical in the field. What is the reason that there are no specific drugs derived from photodynamic therapy? And then other approaches can be described in detail and explained as to how to overcome them

Photodynamic effects on bacterial cells or viruses do not cause the development of pathogen resistance to APDT, since photodynamic inactivation of pathogens is completely nonspecific and acts on several targets. Currently, photosensitizers conjugated with antibodies, folic acid, tyrosine kinase inhibitors have been proposed for the purpose of antitumor photodynamic therapy as targeting cancer cell targets. There are only a few examples of specifically targeted PSs for antimicrobial purposes, e.g. a conjugate with Zanamivir has been proposed [J. Med. Chem. 2009, 52, 4903–4910 4903 DOI: 10.1021/jm900515g], conjugates with antimicrobial peptides [http://dx.doi.org/10.1016/j.sbsr.2016.02.005; https://doi.org/10.1016/j.ijbiomac.2023.125698]. Studies are few and far between, and in addition, the economic justification for obtaining such complex molecules is questionable. Whereas the cationic porphyrins cited in our review can be obtained in sufficient quantities and some are commercially available.

However, a paragraph on the preparation of conjugates of porphyrins with antimicrobial peptides can be added at the request of the reviewer.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manscript titled: "Cationic Porphyrins as Antimicrobial and Antiviral..." by Inga O. Savelyeva and others is a very good overview. Apart from minor corrections, I think it is suitable for publication.

However, the authors should make a few changes first.

Below are my questions, comments and suggestions.

1. The first part of the abstract seems to be a bit misleading, it should be slightly corrected or rewritten.

2. Is "APDT" a word needed in keywords?

3. "In addition, there is also an 44

increase in viral resistance to the antiviral drugs due to their high mutation rate" - why is this happening? Maybe it's worth explaining it a little?

4. PDT - has this abbreviation been explained? Line 50 page 2. I don't think so unless I missed it. I guess every new abbreviation used by the authors should be explained somehow.

5. "Traditionally, PDT has 50

been used in the treatment of malignant and non-malignant neoplasms...." can you cite any other works here, e.g. by Prof. Fiedor, who has been researching these types of effects all his life - and somehow I don't see any reference to his works here?

e.g.

- Lessons from Chlorophylls: Modifications of Porphyrinoids Towards Optimized Solar Energy Conversion - very nice work.

- or any others? Not necessarily Fiedora.

6. "In the field of photodynamic inactivation of the viral particles..." - do you know what this process looks like spectroscopically? I guess not many people were interested in it. A few sentences could be added here on this subject.

7. The last paragraph of the introduction could be written better - so that it clearly indicates the purpose of the work.

8. "2. Principles of antimicrobial PDT" - this part should be written better and clearer. Figers is very cool, but please refine it.

9. Line 132 page 3 - why is there a red comma?

10. I believe that in such a review the authors should show several spectra - 2.2. Photosensitizers for APDT - I'm very interested in this, and I'm probably not the only one?

11. Fig 7 - a bit illegible.

To sum up - I really like the job. I will support you after the corrections.

Author Response

Thank you very much for your comments. We carefully read your review and corrected the manuscript’s text

1. The first part of the abstract seems to be a bit misleading, it should be slightly corrected or rewritten.

Answer. The abstract was slightly corrected.

Antimicrobial photodynamic therapy (APDT) has received a great attention due to the unique ability to kill all currently known classes of microorganisms. To date, infectious diseases caused by bacteria and viruses are one of the main sources of high mortality, mass epidemics and global pandemics among humans. Every year, the emergence of three to four previously unknown species of viruses dangerous to humans is recorded, totaling more than 2/3 of all newly discovered human pathogens. The emergence of bacteria with multidrug resistance leads to the rapid obsolescence of antibiotics and the need to create new types of antibiotics. From this point of view, photodynamic inactivation of viruses and bacteria is of particular interest. The review summarizes on the most relevant mechanisms of antiviral and antibacterial action of APDT, molecular targets and correlation between the structure of cationic porphyrins and their photodynamic activity.

2. Is "APDT" a word needed in keywords?

Answer

“Photodynamic inactivation” and APDT” are similar, APDT can be deleted.

3. "In addition, there is also an 44

increase in viral resistance to the antiviral drugs due to their high mutation rate" - why is this happening? Maybe it's worth explaining it a little?

Answer The following text was added (Line 49, P.2)

Antibiotics and antivirals are the most extensively used chemotherapeutical treatment of infectious diseases. Fast rate of bacteria or viruses’ mutation helps them to survive and receive resistance to the current drugs. Developing of new antibacterial or antiviral drugs is the most common strategy to overcome drug resistance. The widespread use of antibiotic drugs has led to the emergence of so-called "superbacteria", which are resistant to virtually all types of antibiotics. The major mechanisms of drug resistance include reducing drug internalization, overexpressing drug efflux pumps, sequestering entered drugs, modifying drug targets, as well as the formation of biofilms [http://dx.doi.org/10.1016/j.micpath.2016.02.009; https://doi.org/10.1016/S1473-3099(17)30753-3; http://dx.doi.org/10.1101/cshperspect.a026989; https://doi.org/10.1016/j.addr.2021.113941]. At the same time, administration of antibiotics leads to a number of undesirable side effects: negative impact on the normal microflora of the organism, nephro-, oto-, neurotoxic and other effects. In addition, some classes of antibiotics, for example, glycopeptide have a pseudoallergic effect - the so-called "red face syndrome" due to the release of histamine from mast cells.

4. PDT - has this abbreviation been explained? Line 50 page 2. I don't think so unless I missed it. I guess every new abbreviation used by the authors should be explained somehow.

Answer

The abbreviation PDT was indeed missed; we’ve added it.

5. "Traditionally, PDT has 50

been used in the treatment of malignant and non-malignant neoplasms...." can you cite any other works here, e.g. by Prof. Fiedor, who has been researching these types of effects all his life - and somehow I don't see any reference to his works here?

e.g.

- Lessons from Chlorophylls: Modifications of Porphyrinoids Towards Optimized Solar Energy Conversion - very nice work.

- or any others? Not necessarily Fiedora.

Answer

Antitumor effect of PDT has been widely studied in literature. Several new references were added. [10.1002/tcr.201600121; 10.3390/molecules191015938;  10.3390/pharmaceutics15041284; 10.3390/molecules26237268; https://doi.org/10.3390/ijms231710029].

6. "In the field of photodynamic inactivation of the viral particles..." - do you know what this process looks like spectroscopically? I guess not many people were interested in it. A few sentences could be added here on this subject.

Answer

We suggest adding the following text into the part “Principles of antimicrobial PDT”, not directly into the phase "In the field of photodynamic inactivation of the viral particles..." (P.3, line 100)

A detailed study of the interaction of viral particles with photosensitizers was carried out in the work of R. Neris [DOI:10.1038/s41598-018-27855-7]. Fluorescence images of viruses treated with the 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindodicarbocyanine (DiD) were received in this work. DiD only emits fluorescence when the viral envelope fuses with the endosomal membrane during virus endocytosis. Treatment of the DiD-stained viruses with the PS and light stimuli leads to the fluorescence quenching indicating that viruses can’t fuse to the endosomal membrane. Transmission electron microscopy also can give the information about the condition of viral particles. Thus, after PDT procedure viral particles exhibit irregularities in particle structure resulting in symmetry loss, a tendency of viral particle aggregation as well as the appearance of a projection on the surface of the virus.

Images from the paper R. Neris [DOI:10.1038/s41598-018-27855-7]

7. The last paragraph of the introduction could be written better - so that it clearly indicates the purpose of the work.

Answer. Corrected.

Establishing the dependence between the structure of photosensitizing agents and their antimicrobial action is the most important task for improving the APDT method. This review examines the available data on the current state of research on photodynamic inactivation of bacteria, mammalian viruses and bacteriophages using cationic porphyrins. Particular attention is paid to the possible mechanisms of photoinactivation, molecular targets and factors influencing the process of viral inactivation, as well as the current developments in terms of treating Gram-positive and Gram-negative bacteria, the limitations and future perspectives.

 

8. "2. Principles of antimicrobial PDT" - this part should be written better and clearer. Figers is very cool, but please refine it.

Answer.

This part was rewritten.

9. Line 132 page 3 - why is there a red comma?

Answer. It was corrected.

10. I believe that in such a review the authors should show several spectra - 2.2. Photosensitizers for APDT - I'm very interested in this, and I'm probably not the only one?

Answer. Spectra was added into Fig.3B.

11. Fig 7 - a bit illegible.

Answer. The fugure was updated

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for your revision. As I mentioned previously and additionally, you also agreed that you had better describe a paragraph on the preparation of conjugates of porphyrins with antimicrobial peptides. Others are clearly defended.

Comments on the Quality of English Language

Moderate editing of English language required

Author Response

The following paragraph was added

2.4.4. Preparation of conjugates with antimicrobial peptides

Antimicrobial peptides (AMPs) are considered as one of the promising alternatives to the antibiotics. AMPs, also called host-defense peptides, are part of the immune system in bacteria, plants, and animals [147–149]. AMPs were studied against Gram-positive and Gram-negative bacteria, as well as fungi, parasites, and viruses [147]. Conjugation of AMPs that specifically target bacterial cells with PS is a promising synergetic strategy to enhance antimicrobial activity. Recently several studies have demonstrated the perspective of AMPs-PS conjugates. Thus, conjugates of different AMPs with purpurin 18 [150], chlorin e6 [151], 5-(4-carboxyphenyl)-10,15,20-triphenylporphyrin [152] were studied.

Dosselli et al [153] reported a series of novel antimicrobial peptide apidaecin-porphyrin conjugates for E.Coli and methicillin-resistant S.aureus (MRSA) inactivation (Fig.19). The structure of PS consisted of neutral or cationic charged porphyrin 35-36 or porphycene. In this study unfortunately apidaecin targeting properties was lost after conjugation to a bulky PS. The use of another treatment protocol including the repetitive washing after sensitizer delivery improved the activity of conjugate 36 compared to the apidaecin-free porphyrin 35. Conjugate 36 caused total photokilling of E. coli cells at a concentration (10 μM). Despite the controversial result of this work creation of AMPs-PS conjugates requires further investigation.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors answered my questions very well. I believe that the manuscript can be accepted. 

Author Response

Some changes have been done.

Author Response File: Author Response.pdf