HIV-1 Structural Proteins or Cell-Signaling Factors? That Is the Question!

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Journal: Current Issues in Molecular Biology

Manuscript ID: cimb-3011811

Type of manuscript: Review

Title: Hiv-1 structural proteins or cell signaling factors? That is the question!

Authors: Michele Pellegrino, Francesca Giordano, Francesca De Amicis, Maria Marra, Paola Tucci, Stefania Marsico *, Stefano Aquaro, Molecular Microbiology

 

This review work is a summary of reports that the constituent proteins of HIV1, which is generally a causable agent of infectious immunodeficiency, cause or are involved in cancer. The authors write the main text with a focus on the signal transduction system induced, the target cell type, and the general regulation of its biological activity. This reviewer found the introduction to the various events induced by these proteins with great interest. Representative signal transduction pathways are briefly described, and references to more detailed information are also cited.

This reviewer would like to recommend this paper for publication in Current Issues in Molecular Biology as a review after the necessary revisions are made adequately. This reviewer would like to add several sentences to explain or emphasize the relationship to cancer.

 

As the authors stated in their introduction and conclusion, HIV1 infection is deeply involved in the surface proteins of immune-related cells and endothelial cells. For “4. p17” and “5. p24”, there are specific descriptions of the transformation of cells to cancer, while for “2. Gp120”, and “3. Gp41”, there are few descriptions related to the actual ous formation to cancer. "Exogenous" protein (HIV1 structural protein) triggers signaling for immune and inflammatory responses. Those are reasonable. So, this reviewer believes that adding a line or two to each part of the paper to emphasize that this is ``cancer-related'' signaling. That will increase the overall persuasiveness of the paper. This is because there are so many related proteins and abbreviations in the paper.

Author Response

Dear Reviewer 1,

Thank you for your very useful clarifications. It is true that we had taken for granted the relationship between cancer and the inflammatory and immune response activated by the viral proteins gp120 and gp41. It is correct to be more explicit and so we have added the following sentences in paragraph 2:

The inflammatory pathways STAT3, NF-κB, PI3K/AKT, activated by gp120 in cells of the immune system, directly or indirectly alter the microenvironment producing a tumor microenvironment and favoring the development of lymphomas [45,46]. Furthermore, the alteration of the activity of immune cells caused by the HIV-1 glycoprotein could delay and blunt the immune response against cancer cells and favor the evolution of cancer in HIV-positive patients. (highlighted in yellow)

 

And in paragraph 3:

T cells play a critical role in controlling cancer cells. Gp41 inhibition of activation and apoptosis, through PKC and Bid/Caspase-3 activation, respectively, produces dysregulation of T cell activity that could favor the evolution of cancer. (highlighted in yellow)

 

I hope I have satisfied your request.

Thanks again

Dear Reviewer 1,

Thank you for your very useful clarifications. It is true that we had taken for granted the relationship between cancer and the inflammatory and immune response activated by the viral proteins gp120 and gp41. It is correct to be more explicit and so we have added the following sentences in paragraph 2:

The inflammatory pathways STAT3, NF-κB, PI3K/AKT, activated by gp120 in cells of the immune system, directly or indirectly alter the microenvironment producing a tumor microenvironment and favoring the development of lymphomas [45,46]. Furthermore, the alteration of the activity of immune cells caused by the HIV-1 glycoprotein could delay and blunt the immune response against cancer cells and favor the evolution of cancer in HIV-positive patients. (highlighted in yellow)

 

And in paragraph 3:

T cells play a critical role in controlling cancer cells. Gp41 inhibition of activation and apoptosis, through PKC and Bid/Caspase-3 activation, respectively, produces dysregulation of T cell activity that could favor the evolution of cancer. (highlighted in yellow)

 

I hope I have satisfied your request.

Thanks again

Dear Reviewer 1,

Thank you for your very useful clarifications. It is true that we had taken for granted the relationship between cancer and the inflammatory and immune response activated by the viral proteins gp120 and gp41. It is correct to be more explicit and so we have added the following sentences in paragraph 2:

The inflammatory pathways STAT3, NF-κB, PI3K/AKT, activated by gp120 in cells of the immune system, directly or indirectly alter the microenvironment producing a tumor microenvironment and favoring the development of lymphomas [45,46]. Furthermore, the alteration of the activity of immune cells caused by the HIV-1 glycoprotein could delay and blunt the immune response against cancer cells and favor the evolution of cancer in HIV-positive patients. (highlighted in yellow)

 

And in paragraph 3:

T cells play a critical role in controlling cancer cells. Gp41 inhibition of activation and apoptosis, through PKC and Bid/Caspase-3 activation, respectively, produces dysregulation of T cell activity that could favor the evolution of cancer. (highlighted in yellow)

 

I hope I have satisfied your request.

Thanks again

Dear Reviewer 1,

Thank you for your very useful clarifications. It is true that we had taken for granted the relationship between cancer and the inflammatory and immune response activated by the viral proteins gp120 and gp41. It is correct to be more explicit and so we have added the following sentences in paragraph 2:

The inflammatory pathways STAT3, NF-κB, PI3K/AKT, activated by gp120 in cells of the immune system, directly or indirectly alter the microenvironment producing a tumor microenvironment and favoring the development of lymphomas [45,46]. Furthermore, the alteration of the activity of immune cells caused by the HIV-1 glycoprotein could delay and blunt the immune response against cancer cells and favor the evolution of cancer in HIV-positive patients. (highlighted in yellow)

 

And in paragraph 3:

T cells play a critical role in controlling cancer cells. Gp41 inhibition of activation and apoptosis, through PKC and Bid/Caspase-3 activation, respectively, produces dysregulation of T cell activity that could favor the evolution of cancer. (highlighted in yellow)

 

I hope I have satisfied your request.

Thanks again

Dear Reviewer 1,

Thank you for your very useful clarifications. It is true that we had taken for granted the relationship between cancer and the inflammatory and immune response activated by the viral proteins gp120 and gp41. It is correct to be more explicit and so we have added the following sentences in paragraph 2:

The inflammatory pathways STAT3, NF-κB, PI3K/AKT, activated by gp120 in cells of the immune system, directly or indirectly alter the microenvironment producing a tumor microenvironment and favoring the development of lymphomas [45,46]. Furthermore, the alteration of the activity of immune cells caused by the HIV-1 glycoprotein could delay and blunt the immune response against cancer cells and favor the evolution of cancer in HIV-positive patients. (highlighted in yellow)

 

And in paragraph 3:

T cells play a critical role in controlling cancer cells. Gp41 inhibition of activation and apoptosis, through PKC and Bid/Caspase-3 activation, respectively, produces dysregulation of T cell activity that could favor the evolution of cancer. (highlighted in yellow)

 

I hope I have satisfied your request.

Thanks again

Dear Reviewer 1,

Thank you for your very useful clarifications. It is true that we had taken for granted the relationship between cancer and the inflammatory and immune response activated by the viral proteins gp120 and gp41. It is correct to be more explicit and so we have added the following sentences in paragraph 2:

The inflammatory pathways STAT3, NF-κB, PI3K/AKT, activated by gp120 in cells of the immune system, directly or indirectly alter the microenvironment producing a tumor microenvironment and favoring the development of lymphomas [45,46]. Furthermore, the alteration of the activity of immune cells caused by the HIV-1 glycoprotein could delay and blunt the immune response against cancer cells and favor the evolution of cancer in HIV-positive patients. (highlighted in yellow)

 

And in paragraph 3:

T cells play a critical role in controlling cancer cells. Gp41 inhibition of activation and apoptosis, through PKC and Bid/Caspase-3 activation, respectively, produces dysregulation of T cell activity that could favor the evolution of cancer. (highlighted in yellow)

 

I hope I have satisfied your request.

Thanks again

Dear Reviewer 1,

Thank you for your very useful clarifications. It is true that we had taken for granted the relationship between cancer and the inflammatory and immune response activated by the viral proteins gp120 and gp41. It is correct to be more explicit and so we have added the following sentences in paragraph 2:

The inflammatory pathways STAT3, NF-κB, PI3K/AKT, activated by gp120 in cells of the immune system, directly or indirectly alter the microenvironment producing a tumor microenvironment and favoring the development of lymphomas [45,46]. Furthermore, the alteration of the activity of immune cells caused by the HIV-1 glycoprotein could delay and blunt the immune response against cancer cells and favor the evolution of cancer in HIV-positive patients. (highlighted in yellow)

 

And in paragraph 3:

T cells play a critical role in controlling cancer cells. Gp41 inhibition of activation and apoptosis, through PKC and Bid/Caspase-3 activation, respectively, produces dysregulation of T cell activity that could favor the evolution of cancer. (highlighted in yellow)

 

I hope I have satisfied your request.

Thanks again

Dear Reviewer 1,

Thank you for your very useful clarifications. It is true that we had taken for granted the relationship between cancer and the inflammatory and immune response activated by the viral proteins gp120 and gp41. It is correct to be more explicit and so we have added the following sentences in paragraph 2:

The inflammatory pathways STAT3, NF-κB, PI3K/AKT, activated by gp120 in cells of the immune system, directly or indirectly alter the microenvironment producing a tumor microenvironment and favoring the development of lymphomas [45,46]. Furthermore, the alteration of the activity of immune cells caused by the HIV-1 glycoprotein could delay and blunt the immune response against cancer cells and favor the evolution of cancer in HIV-positive patients. (highlighted in yellow)

 

And in paragraph 3:

T cells play a critical role in controlling cancer cells. Gp41 inhibition of activation and apoptosis, through PKC and Bid/Caspase-3 activation, respectively, produces dysregulation of T cell activity that could favor the evolution of cancer. (highlighted in yellow)

 

I hope I have satisfied your request.

Thanks again

Reviewer 2 Report

Comments and Suggestions for Authors

Pellegrino et al. summarize the multifaceted functionality of several HIV-1 proteins. They discuss their major role in virus replication as well as emerging evidence that several of these proteins may have additional functions that directly, or indirectly, influence virus replication or pathogenesis. In general, this is an interesting review article, but some small things should be addressed. The writing and grammar need some attention, especially early on in the manuscript where sentence structure and grammatical errors are prevalent. The authors should also consider including some statements regarding the fact that many of the “alternative functions” for these HIV proteins are described in a single study and have not been independently validated by other groups or by follow-up studies from the same group. This is particularly important given that these could be artifactual observations from experimental approaches or cell models being tested.

 

- Grammar, pluralization, noun-pronoun agreement, and general writing quality need to be improved in the early portions of the manuscript. For example, the introduction has grammatical errors or odd sentence structure/writing on lines 30, 37, 38-39, 42-43, and 44-45. Oddly, the rest of the manuscript reads much more clearly and there are less grammatical errors.

 

- Need to double-check that acronyms are consistent throughout, such as HIV or HAART.

 

- Can the authors speculate/elaborate on how these HIV-1 proteins are influencing such a broad range of signaling pathways when patients are successfully responding to HAART? By definition, that would imply that the viral load is undetectable in serum, yet in many instances several viral proteins are able to induce multiple independent signaling cascades in very different cell types/across broad anatomical locations. This does not seem feasible. Moreover, many of the examples given are backed by a single study, should this be mentioned in the text? I would think that more rigorous experimental testing is required to corroborate that these signaling responses are occurring reproducibly, and not just an artifact observed within a single study.

 

- In addition to the point above, can the authors clarify which of these signaling responses directly influence virus replication? It seems as though many of these signaling responses could be chalked up to non-specific artifacts that don’t influence virus replication but rather patient pathology.

 

- The statement that the HIV accessory proteins are not essential for viral replication in the conclusion section is not technically true. They’re not required in some in vitro cell models but are essential for in vivo replication. For example, the Vif-APOBEC3 interaction is absolutely essential for virus replication, as is the Vpu-Tetherin interaction. This should be corrected.

Comments on the Quality of English Language

The sentence structure and grammar in the early portions of the manuscript should be addressed. This includes the abstract, introduction (1), and GP120 (2) sections.

Author Response

Dear Reviewer 2,

Thank you for your attention in reviewing our manuscript. I hope I was able to edit the manuscript correctly according to your instructions.

• I have improved the grammar in the first part of the manuscript.
• I have ensured that the acronyms are consistent throughout the text. If I missed any, please let me know by indicating the exact line. Thank you.
• While it is true that patients respond successfully to HAART, it is also true that these same patients exhibit chronic immune activation and a chronic inflammatory state, which can lead to pathologies apparently unrelated to AIDS. Therefore, I have added the following sentences in the INTRODUCTION (highlighted in blue):

Indeed, patients living with HIV-1 show chronic immune activation and  inflammatory state. This includes B cell activation and increased T cell turnover, leading to elevated levels of cytokines, chemokines [2] and other inflammatory biomarkers [3]. This chronic inflammatory state is associated with the rapid onset of serious pathologies apparently not related to AIDS, such as metabolic syndrome [4,5], coronary heart disease with thrombotic events [6] and neurological disorders [7]. Although AIDS-related cancers have decreased since the advent of HAART, the incidence of lymphomas remains elevated among individuals with chronic HIV-1 infection, with non-Hodgkin lymphoma (NHL) being the predominant type [8]. This indicates that HAART alone, even when effectively suppressing viral replication, does not completely alleviate all HIV-1-associated complications. The most credible hypothesis is that circulating viral proteins may contribute to disease progression in patients where the virus is undetectable and in the absence of active HIV-1 replication. In HIV-1 infection, both regulatory and structural proteins, including Tat, Nef, gp120, and p17, can be produced and released from latently infected cells [9,10].

 

Furthermore, in this review, we used some examples of studies supporting the hypothesis that HIV-1 structural proteins are responsible for chronic activation of immune cells and chronic inflammatory state of patients undergoing HAART. I specified this in the INTRODUCTION with the following sentence (highlighted in blue):

In this review we highlight some representative examples of studies on the signaling capacity of HIV-1 structural proteins…..

 

and in the CONCLUSIONS (highlighted in blue):

 

Further experimental studies are needed to confirm the activation of signal transduction pathways in different cell types by HIV-1 structural proteins, as many examples reported in this review are present as single studies. Furthermore, further clinical studies on patients under HAART treatment would be appropriate, to confirm both the presence of individual viral proteins in serum and any pathogenic effects on organs and tissues.

 

-The described signaling responses do not affect “virus replication”, but can amplify infection. Then I edited the sentence on line 65 and added the sentence highlighted in blue in paragraph 3 (gp41):

 

The interaction of gp41 or gp41 fragments containing the loop sequence with CD74 highlights its ability to interact with host cell proteins, thereby influencing signaling pathways important for cell proliferation and HIV infection. The authors hypothesized that CD74 plays a role in the early stages of HIV-1 infection by interacting with the gp41 loop region. However, the observed inhibition of HIV-1 infection upon silencing CD74 likely occurs due to the stopping of the CD74-mediated ERK/MAPK pathway [45].

 

- The incorrect statement that “accessory proteins are not essential for HIV replication”, has been corrected and I wrote this in the CONCLUSIONS line 465:

 

The HIV "accessory proteins" (Nef, Vif, Vpr, and Vpu or Vpx in HIV-2) enhance the efficiency of viral replication through interactions with human cells.

 

Thank you

Dear Reviewer 2,

Thank you for your attention in reviewing our manuscript. I hope I was able to edit the manuscript correctly according to your instructions.

• I have improved the grammar in the first part of the manuscript.
• I have ensured that the acronyms are consistent throughout the text. If I missed any, please let me know by indicating the exact line. Thank you.
• While it is true that patients respond successfully to HAART, it is also true that these same patients exhibit chronic immune activation and a chronic inflammatory state, which can lead to pathologies apparently unrelated to AIDS. Therefore, I have added the following sentences in the INTRODUCTION (highlighted in blue):

Indeed, patients living with HIV-1 show chronic immune activation and  inflammatory state. This includes B cell activation and increased T cell turnover, leading to elevated levels of cytokines, chemokines [2] and other inflammatory biomarkers [3]. This chronic inflammatory state is associated with the rapid onset of serious pathologies apparently not related to AIDS, such as metabolic syndrome [4,5], coronary heart disease with thrombotic events [6] and neurological disorders [7]. Although AIDS-related cancers have decreased since the advent of HAART, the incidence of lymphomas remains elevated among individuals with chronic HIV-1 infection, with non-Hodgkin lymphoma (NHL) being the predominant type [8]. This indicates that HAART alone, even when effectively suppressing viral replication, does not completely alleviate all HIV-1-associated complications. The most credible hypothesis is that circulating viral proteins may contribute to disease progression in patients where the virus is undetectable and in the absence of active HIV-1 replication. In HIV-1 infection, both regulatory and structural proteins, including Tat, Nef, gp120, and p17, can be produced and released from latently infected cells [9,10].

 

Furthermore, in this review, we used some examples of studies supporting the hypothesis that HIV-1 structural proteins are responsible for chronic activation of immune cells and chronic inflammatory state of patients undergoing HAART. I specified this in the INTRODUCTION with the following sentence (highlighted in blue):

In this review we highlight some representative examples of studies on the signaling capacity of HIV-1 structural proteins…..

 

and in the CONCLUSIONS (highlighted in blue):

 

Further experimental studies are needed to confirm the activation of signal transduction pathways in different cell types by HIV-1 structural proteins, as many examples reported in this review are present as single studies. Furthermore, further clinical studies on patients under HAART treatment would be appropriate, to confirm both the presence of individual viral proteins in serum and any pathogenic effects on organs and tissues.

 

-The described signaling responses do not affect “virus replication”, but can amplify infection. Then I edited the sentence on line 65 and added the sentence highlighted in blue in paragraph 3 (gp41):

 

The interaction of gp41 or gp41 fragments containing the loop sequence with CD74 highlights its ability to interact with host cell proteins, thereby influencing signaling pathways important for cell proliferation and HIV infection. The authors hypothesized that CD74 plays a role in the early stages of HIV-1 infection by interacting with the gp41 loop region. However, the observed inhibition of HIV-1 infection upon silencing CD74 likely occurs due to the stopping of the CD74-mediated ERK/MAPK pathway [45].

 

- The incorrect statement that “accessory proteins are not essential for HIV replication”, has been corrected and I wrote this in the CONCLUSIONS line 465:

 

The HIV "accessory proteins" (Nef, Vif, Vpr, and Vpu or Vpx in HIV-2) enhance the efficiency of viral replication through interactions with human cells.

 

Thank you

Dear Reviewer 2,

Thank you for your attention in reviewing our manuscript. I hope I was able to edit the manuscript correctly according to your instructions.

• I have improved the grammar in the first part of the manuscript.
• I have ensured that the acronyms are consistent throughout the text. If I missed any, please let me know by indicating the exact line. Thank you.
• While it is true that patients respond successfully to HAART, it is also true that these same patients exhibit chronic immune activation and a chronic inflammatory state, which can lead to pathologies apparently unrelated to AIDS. Therefore, I have added the following sentences in the INTRODUCTION (highlighted in blue):

Indeed, patients living with HIV-1 show chronic immune activation and  inflammatory state. This includes B cell activation and increased T cell turnover, leading to elevated levels of cytokines, chemokines [2] and other inflammatory biomarkers [3]. This chronic inflammatory state is associated with the rapid onset of serious pathologies apparently not related to AIDS, such as metabolic syndrome [4,5], coronary heart disease with thrombotic events [6] and neurological disorders [7]. Although AIDS-related cancers have decreased since the advent of HAART, the incidence of lymphomas remains elevated among individuals with chronic HIV-1 infection, with non-Hodgkin lymphoma (NHL) being the predominant type [8]. This indicates that HAART alone, even when effectively suppressing viral replication, does not completely alleviate all HIV-1-associated complications. The most credible hypothesis is that circulating viral proteins may contribute to disease progression in patients where the virus is undetectable and in the absence of active HIV-1 replication. In HIV-1 infection, both regulatory and structural proteins, including Tat, Nef, gp120, and p17, can be produced and released from latently infected cells [9,10].

 

Furthermore, in this review, we used some examples of studies supporting the hypothesis that HIV-1 structural proteins are responsible for chronic activation of immune cells and chronic inflammatory state of patients undergoing HAART. I specified this in the INTRODUCTION with the following sentence (highlighted in blue):

In this review we highlight some representative examples of studies on the signaling capacity of HIV-1 structural proteins…..

 

and in the CONCLUSIONS (highlighted in blue):

 

Further experimental studies are needed to confirm the activation of signal transduction pathways in different cell types by HIV-1 structural proteins, as many examples reported in this review are present as single studies. Furthermore, further clinical studies on patients under HAART treatment would be appropriate, to confirm both the presence of individual viral proteins in serum and any pathogenic effects on organs and tissues.

 

-The described signaling responses do not affect “virus replication”, but can amplify infection. Then I edited the sentence on line 65 and added the sentence highlighted in blue in paragraph 3 (gp41):

 

The interaction of gp41 or gp41 fragments containing the loop sequence with CD74 highlights its ability to interact with host cell proteins, thereby influencing signaling pathways important for cell proliferation and HIV infection. The authors hypothesized that CD74 plays a role in the early stages of HIV-1 infection by interacting with the gp41 loop region. However, the observed inhibition of HIV-1 infection upon silencing CD74 likely occurs due to the stopping of the CD74-mediated ERK/MAPK pathway [45].

 

- The incorrect statement that “accessory proteins are not essential for HIV replication”, has been corrected and I wrote this in the CONCLUSIONS line 465:

 

The HIV "accessory proteins" (Nef, Vif, Vpr, and Vpu or Vpx in HIV-2) enhance the efficiency of viral replication through interactions with human cells.

 

Thank you