Submited on: 09 Sep 2010 03:07:12 PM GMT
Published on: 09 Sep 2010 09:08:41 PM GMT
 

1 Is the subject of the article within the scope of the subject category? Yes
2 Are the interpretations / conclusions sound and justified by the data? No
3 Is this a new and original contribution? Yes
4 Does this paper exemplify an awareness of other research on the topic? Yes
5 Are structure and length satisfactory? Yes
6 Can you suggest brief additions or amendments or an introductory statement that will increase the value of this paper for an international audience? Yes
7 Can you suggest any reductions in the paper, or deletions of parts? No
8 Is the quality of the diction satisfactory? Yes
9 Are the illustrations and tables necessary and acceptable? No
10 Are the references adequate and are they all necessary? Yes
11 Are the keywords and abstract or summary informative? Yes
  • Other Comments:

    2. This article is hypothesis driven; no data is provided.

     

    6. Need to address issue of protection and delivey of genes to target cells.

     

    9. No illustrations and tyables are provided.

     

    General comments: Interesting article, but certain concerns remain:

     

    a. A bigger issue in gene delivey is protecing genes from degrading nucleases and delivering them to target cells. This aproach does not adress such issues.

     

    b. For eficient gene delivery, insertion of foreign genes in the nucleus in target cells is a prerequisite. Not sure how bacterial proteins can help here, as prokaryotic cells do not have a well defined nuclear membrane, and thus the translation in eukaryotic system is questionable.

     

    c. The specifiity of the modified cells to the desired genes seems to be absent; any DNA, including oncogenes, can enter and infect target cells.

     

     

     

     

     

  • Competing interests:
    None
  • Invited by the author to review this article? :
    No
  • Have you previously published on this or a similar topic?:
    Yes
  • References:
    1. Roy, I., Mitra, S., Maitra, A. N. and Mozumdar, S. Calcium phosphate nanoparticles as novel non-viral vectors for targeted gene delivery. Int. J. Pharm. 2003, 250, 25-33. 2. Roy, I., Ohulchansky, T.Y., Bharali, D.J., Pudavar, H.E., Mistretta, R.A., Kaur, N. and Prasad, P.N. Optical tracking of organically modified silica nanoparticles as DNA carriers: A nonviral, nanomedicine approach for gene delivery. Proc. Natl. Acad. Sci., USA. 2005, 102 (2), 279-284. 3. Roy, I., Stachowiak, M.K., Bergey, E.J. Non viral gene transfection nanoparticles: Functions and applications in CNS. Nanomedicine. 2008, 4 (2), 89-97.
  • Experience and credentials in the specific area of science:

    Non viral gene delivery

  • How to cite:  Roy I .Protection and delivery of genes to cells is a bigger challenge to overcome [Review of the article 'Hypothesis, Inserting Bacterial Natural Transformation Protein Complexes Into Human Cells For Efficient Gene Therapy Using Naked Dna ' by Tolmachov O].WebmedCentral 2011;2(4):WMCRW00706
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the nuclear enveloppe is the target
Posted by Mr. Justin Teissie on 21 Sep 2010 10:10:08 AM GMT

  • Other Comments: Hypothesis : inserting bacterial transformation protein complexes? Gene therapy using naked DNA is a safe method where the risks associated with viral methods is avoided. Its weakness is that it is associated to a low efficiency. The main problem is the penetration of the plasmid inside the nucleus. It is rather easy to introduce a large number of copies in the cytosol but only a very limited number of plasmids is then allowed to be transferred in the nucleus to be processed. The hypothesis that this can be obtained by transferring bacterial transformation protein complexes has two weaknesses: The complex must inserted in the nucleus envelope. The methods which are proposed do not seem to be realistic. Direct insertion supposes that the complex is already introduced in the cytosol (but with no insertion in the plasma membrane). Getting its localized expression after gene transfer is the only relevant method but supposes that an efficient method for gene transfer is already present. There is no evidence that a single stranded DNA will work in the nucleus. Results obtained with AAV vectors are obtained with the complex brought by the virus not with the naked single stranded DNA. Gene corrections is obtained with smaller DNA fragments but one may wonder if it is not easier to use short specific oligonucleotides to obtain the desired correction. It was shown in 2001 that hybridizing a bifunctional peptide nucleic acid (PNA) consisting of a nucleic acid binding moiety and a nuclear localization signal (NLS) to oligonucleotides a nuclear translocation was obtained. This appears as a simpler method. Delivering oligonucleotides to the cytosol is not a technical problem.
  • Competing interests:
    no
  • Invited by the author to review this article? :
    No
  • Have you previously published on this or a similar topic?:
    Yes
  • References:
    None
  • Experience and credentials in the specific area of science:
    electrotransfection on cells and tissues electroinsertion of membrane proteins electrofusion
  • How to cite:  Teissie J .the nuclear enveloppe is the target[Review of the article 'Hypothesis, Inserting Bacterial Natural Transformation Protein Complexes Into Human Cells For Efficient Gene Therapy Using Naked Dna ' by Tolmachov O].WebmedCentral 2011;1(9):WMCRW0040
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Penetration of naked DNA into the cytosol of mammalian cells is not a trivial task under standard circumstances. This is because the major inward route for DNA is thought to be via endocytosis. Endosomes with DNA are gradually acidified and the bulk of DNA is degraded. Transfectosomes sitting in the human plasma membrane would have a benefit of delivering DNA directly into the cytosol, circumventing the deadly endosomes. This is one of the important advantages of transfectosomes. Indeed, transfer of extraneous single-stranded DNA via nuclear envelope without help of a mammalian viral vector was not previously reported. Expression of transgenes from single-polarity single-stranded DNA delivered with filamentous bacteriophages, which was shown by D. Larocca and co-workers, is likely to be due to DNA entry into nucleosol during cell division when nuclear envelope is absent. I interpret transgene expression results with single-polarity AAV vectors and filamentous bacteriophages as indicative for successful expression of single-stranded DNA getting into the nucleus via transfectosomes sitting in the nuclear envelope. It is clearly a challenge to obtain functional transfectosomes in the nuclear envelope. In addition to the protein transport and assembly problems, one can mention immune reaction problems and potential protease attack. However, at a closer look, the problems seem to be surmountable. The goal of ultra-efficient and non-toxic gene transfer into post-mitotic cells is worth fighting for, there is obvious agreement on this point between me and Prof. Justin Teissie. Yes, there are existing techniques for non-viral intra-nuclear delivery of DNA, e.g. we previously used both PNA-NLS method and our own TetR-NLS method [Vaysse L; Harbottle R; Bigger B; Bergau A; Tolmachov O; Coutelle C. 2004. Development of a self-assembling nuclear targeting vector system based on the tetracycline repressor protein. J Biol Chem. 279:5555-5564]. These methods rely on DNA complexing with toxic cationic lipids, which limits therapeutic applicability of these gene transfer approaches. Yes, gene repair with short oligonucleotides is well-documented [Wang Z, Zhou ZJ, Liu DP, Huang JD. Single-stranded oligonucleotide-mediated gene repair in mammalian cells has a mechanism distinct from homologous recombination repair. Biochem Biophys Res Commun. 2006; 350(3):568-73.] Again, toxic cationic lipids were involved in gene delivery. Most importantly, currently obtained efficiency of gene repair is not sufficient to achieve curative effects in patients.
Responded by Dr. Oleg E Tolmachov on 07 Oct 2010 02:13:31 PM