Networked Pathological Mechanisms of Central Sympathetic Nervous System Regulation in Heart Failure and Novel Paradigms for Targeted Intervention

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript presents a valuable and comprehensive review of the current understanding of the pathophysiology of neurohumoral regulation in HF. I have only a few clarifications and suggestions that could potentially improve the manuscript prior to publication.

1. While the transcytosis of extracellular vesicles (EVs) across the blood-brain barrier (BBB) is a phenomenon documented in the literature, the in vivo efficiency of this process specifically in the context of HF—and the quantitative delivery of cargo specifically to RVLM neurons—remains a subject of ongoing investigation and debate. What proportion of circulating EVs are estimated to actually reach the RVLM parenchyma compared to peripheral clearance organs such as the liver or spleen? How significant is the contribution of non-vesicular (free) circulating miRNAs? Given that HF is associated with increased BBB permeability, these free miRNAs might also penetrate the brain and contribute to the observed pathology.
2. The manuscript identifies MAPK6 (ERK3) as a key mediator in the RVLM inflammatory response linked to let-7i-5p downregulation. However, MAPK6 is a relatively understudied atypical kinase, and its direct, canonical link to IL-1β secretion within RVLM neurons is not as firmly established or widely accepted as the classical NF-κB or MAPK p38/JNK pathways. The authors should consider either: (a) providing additional supporting references that specifically validate the MAPK6/IL-1β signaling axis in neuronal tissue or the RVLM, or (b) softening the language to reflect the nascent nature of this specific pathway, presenting it as a proposed mechanism or hypothesis based on target prediction rather than a fully validated physiological event.
3. The review excellently details the molecular targets for intervention (e.g., SGLT2 inhibitors, miRNA antagomirs, TUDCA). However, the discussion would be strengthened by a brief, balanced acknowledgment of the translational hurdles associated with these inhibitor-based therapies. There is currently no discussion regarding potential off-target or systemic side effects of chronic central pathway inhibition. Furthermore, the financial component (pharmacoeconomics) is a critical factor in the clinical adoption of advanced biologics (such as miRNA therapies or CNS-targeted delivery systems) compared to repurposed small molecules.
4. The current figure legends are extremely lengthy and, in their current form, largely duplicate the detailed mechanistic descriptions found in the main body of the text. It is recommended to significantly shorten these legends for improved reader comprehension.

Author Response

Response to reviewer 1

We are very grateful for the valuable comments by the reviewers. We tried our best to address the issue raised by the reviewers. The responses to the comments were highlighted in blue colored text.

 

1，While the transcytosis of extracellular vesicles (EVs) across the blood-brain barrier (BBB) is a phenomenon documented in the literature, the in vivo efficiency of this process specifically in the context of HF—and the quantitative delivery of cargo specifically to RVLM neurons—remains a subject of ongoing investigation and debate. What proportion of circulating EVs are estimated to actually reach the RVLM parenchyma compared to peripheral clearance organs such as the liver or spleen? How significant is the contribution of non-vesicular (free) circulating miRNAs? Given that HF is associated with increased BBB permeability, these free miRNAs might also penetrate the brain and contribute to the observed pathology.

Response: We thank you for your comments. We have supplemented and revised the relevant content regarding the in vivo transcytosis efficiency of extracellular vesicles across the blood–brain barrier, the quantitative delivery to RVLM neurons, the proportion of circulating EVs reaching the RVLM parenchyma compared with the liver and spleen, and the potential contribution of non‑vesicular free circulating miRNAs in heart failure. The revised content is shown on Page 5, Lines 171–188.

 

2，The manuscript identifies MAPK6 (ERK3) as a key mediator in the RVLM inflammatory response linked to let-7i-5p downregulation. However, MAPK6 is a relatively understudied atypical kinase, and its direct, canonical link to IL-1β secretion within RVLM neurons is not as firmly established or widely accepted as the classical NF-κB or MAPK p38/JNK pathways. The authors should consider either: (a) providing additional supporting references that specifically validate the MAPK6/IL-1β signaling axis in neuronal tissue or the RVLM, or (b) softening the language to reflect the nascent nature of this specific pathway, presenting it as a proposed mechanism or hypothesis based on target prediction rather than a fully validated physiological event.

Response: We greatly appreciate this insightful and professional comment. We have toned down the relevant statements and clarified that the MAPK6/IL‑1β axis in the RVLM is a proposed mechanism based on target prediction rather than a fully validated physiological event, as shown on Page 5, Lines 164–169..

 

3，The review excellently details the molecular targets for intervention (e.g., SGLT2 inhibitors, miRNA antagomirs, TUDCA). However, the discussion would be strengthened by a brief, balanced acknowledgment of the translational hurdles associated with these inhibitor-based therapies. There is currently no discussion regarding potential off-target or systemic side effects of chronic central pathway inhibition. Furthermore, the financial component (pharmacoeconomics) is a critical factor in the clinical adoption of advanced biologics (such as miRNA therapies or CNS-targeted delivery systems) compared to repurposed small molecules..

Response: We appreciate this valuable comment. We have added a new Section 4.8 to address the translational hurdles, off-target effects, and pharmacoeconomic issues of central targeted interventions, as shown on Page 21, Lines 759–773.

 

4，The current figure legends are extremely lengthy and, in their current form, largely duplicate the detailed mechanistic descriptions found in the main body of the text. It is recommended to significantly shorten these legends for improved reader comprehension.

Response: We thank you for this constructive suggestion on improving readability. We have substantially shortened all figure legends to eliminate redundancy with the main text and enhance reader comprehension, as shown on Page 4, Lines 123–124; Page 6, Lines 192–193; Page 8, Lines 266–267; Page 10, Lines 323–324; and Page 22, Lines 776–777.

 

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have summarized both the historical and current context of neurocardiac regulation in heart failure from the perspective of the central nervous system. As stated, much of the literature focuses on the peripheral nerve endings and changes within the cardiomyocytes, this review was refreshing to read more about the CNS role in sympathetic regulation of the heart. Based off the title and stated scope, the authors have achieved a well written review. The only thing I can say that could improve this manuscript would be an abbreviations table that readers can refer back to instead of finding it back in the body of the text. Great work!

Author Response

Response to reviewer 2

We are very grateful for the valuable comments by the reviewers. We tried our best to address the issue raised by the reviewers. The responses to the comments were highlighted in blue colored text.

 

The authors have summarized both the historical and current context of neurocardiac regulation in heart failure from the perspective of the central nervous system. As stated, much of the literature focuses on the peripheral nerve endings and changes within the cardiomyocytes, this review was refreshing to read more about the CNS role in sympathetic regulation of the heart. Based off the title and stated scope, the authors have achieved a well written review. The only thing I can say that could improve this manuscript would be an abbreviations table that readers can refer back to instead of finding it back in the body of the text. Great work!

 

Response: We greatly appreciate your positive and encouraging comments. Following your helpful suggestion, we have added a comprehensive abbreviations table for easier reference, as shown on Page 24–26, Lines 844–926..

 

 

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript provides a comprehensive overview of central mechanisms underlying sympathetic overactivation in heart failure, covering multiple interconnected pathways. The topic is of potential interest; however, several critical issues limit the current quality and clarity of the review. Major revisions are required before the manuscript can be considered for publication.

1. While the authors have summarized a wide range of mechanisms, the review remains largely descriptive and does not sufficiently distinguish between well-established findings and emerging or speculative evidence. The inclusion of critical evaluation (e.g., consensus vs. controversy, strengths and limitations of cited studies) would significantly enhance the scientific rigor and depth of the manuscript.
2. In several sections, the manuscript uses strong causal language (e.g., “core driver,” “directly mediates”) to describe relationships that are primarily based on associative or preclinical data. This may lead to overinterpretation. The authors are encouraged to adopt more cautious wording and clearly differentiate between correlation and causation, particularly when evidence is derived from animal models.
3. Although multiple pathways are discussed, they are presented in a largely parallel manner without a clear hierarchical framework. The manuscript would benefit from organizing these mechanisms into functional layers (e.g., initiation, amplification, and execution phases) and explicitly describing their interactions to better reflect a systems-level understanding.
4. The current structure treats each signaling pathway as relatively independent. However, increasing evidence supports extensive cross-talk among pathways such as ER stress, oxidative stress, inflammation, and MAPK signaling. The authors should strengthen the discussion on these interactions to avoid a fragmented presentation and to support the proposed network-based perspective.
5. The manuscript focuses heavily on mechanistic insights but provides limited discussion on how these central mechanisms may translate into therapeutic strategies. Expanding on the clinical implications, including potential central targets and their relevance to current or emerging treatments, would improve the translational value of the review.

Author Response

Response to reviewer 3

We are very grateful for the valuable comments by the reviewers. We tried our best to address the issue raised by the reviewers. The responses to the comments were highlighted in blue colored text.

 

1，While the authors have summarized a wide range of mechanisms, the review remains largely descriptive and does not sufficiently distinguish between well-established findings and emerging or speculative evidence. The inclusion of critical evaluation (e.g., consensus vs. controversy, strengths and limitations of cited studies) would significantly enhance the scientific rigor and depth of the manuscript.

Response: We appreciate this valuable and professional comment. We have carefully revised and supplemented the critical analysis and critical evaluation of the relevant content in the manuscript in accordance with your professional comments. We have added in-depth discussions and clear distinctions between consensus conclusions, controversial viewpoints, and speculative evidence, and strengthened the critical evaluation of the relevant research, as shown in Page 4 (Lines 131–137), Page 5 (Lines 171–188), Page 7 (Lines 228–229, 246–248, 262–263), Page 9 (Lines 286-289, 304–307, 319–320), Page 11 (Lines 384–387), Page 13 (Lines 438–442), Page 15 (Lines 483–489), and Page 16 (Lines 531–534).

 

2，In several sections, the manuscript uses strong causal language (e.g., “core driver,” “directly mediates”) to describe relationships that are primarily based on associative or preclinical data. This may lead to overinterpretation. The authors are encouraged to adopt more cautious wording and clearly differentiate between correlation and causation, particularly when evidence is derived from animal models.

Response: We appreciate this valuable comment. We have revised the overly strong causal expressions throughout the manuscript and adopted more cautious wording to clearly distinguish between correlation and causation, especially for conclusions supported only by preclinical animal data, as shown on Page 1 (Lines 10–13), Page 2 (Lines 42–43 and 60–61), Page 5 (Lines 164–169), Page 6 (Lines 205–208), Page 9 (Line 282), Page 11 (Lines 242–243).

 

3，Although multiple pathways are discussed, they are presented in a largely parallel manner without a clear hierarchical framework. The manuscript would benefit from organizing these mechanisms into functional layers (e.g., initiation, amplification, and execution phases) and explicitly describing their interactions to better reflect a systems-level understanding.

Response: Thank you for this constructive suggestion. We have reorganized all pathological mechanisms into a clear hierarchical framework of initiation, amplification, and execution phases, and supplemented detailed explanations of their crosstalk and interactions to reflect a systems-level understanding, as shown in Chapter 3.

 

4，The current structure treats each signaling pathway as relatively independent. However, increasing evidence supports extensive cross-talk among pathways such as ER stress, oxidative stress, inflammation, and MAPK signaling. The authors should strengthen the discussion on these interactions to avoid a fragmented presentation and to support the proposed network-based perspective.

Response: Thank you for this insightful suggestion. We have strengthened the discussion on the extensive crosstalk among ER stress, oxidative stress, inflammation, and MAPK signaling pathways to avoid a fragmented presentation and better support our network‑based perspective, as shown on Page 4 (Lines 131–137) and Page 16 (Lines 535–552).

 

5，The manuscript focuses heavily on mechanistic insights but provides limited discussion on how these central mechanisms may translate into therapeutic strategies. Expanding on the clinical implications, including potential central targets and their relevance to current or emerging treatments, would improve the translational value of the review.

Response: Thank you for this constructive suggestion. We have expanded the discussion on the translational implications of central mechanisms, including potential central targets and their connections with current and emerging therapies, to enhance the translational value of the review, as shown on Page 17 (Lines 574–590, 595–599), Page 18 (Lines 607–609, 612–614, 629–637, 646–647, 653–655), Page 19 (Lines 658–666, 669–674, 688–692, 697–701), Page 20 (Lines 711–713, 727–731, 744–748), and Page 21 (Lines 759–773) in Chapter 4.

 

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Accept in present form.