Pharmacokinetics and Molecular Modeling Indicate nAChRα4-Derived Peptide HAEE Goes through the Blood–Brain Barrier
, Vladimir A. Mitkevich 1, Stanislav I. Shram 2, Alexei A. Adzhubei 1, Anna P. Tolstova 1, Oleg B. Talibov 3, Alexander K. Dadayan 2, Nikolai F. Myasoyedov 2, Alexander A. Makarov 1 and Sergey A. Kozin 1,*Round 1
Reviewer 1 Report
It is an interesting and well documented study addressing the pharmacokinetics of HAEE peptide administered in vivo. The idea of using this peptide to prevent amyloid-beta aggregation in the brain is quite relevant. A principal question, which is not even mentioned in the manuscript, is that the main target of amyloid-beta in the brain is considered to be alpha7 nAChR (Parri HR, Dineley KT. Nicotinic acetylcholine receptor interaction with β-amyloid: molecular, cellular, and physiological consequences. Curr Alzheimer Res. 2010; 7( 1): 27-39; Wang HY, Lee DH, D'Andrea MR, Peterson PA, Shank RP, Reitz AB. β-Amyloid 1–42 binds to α7 nicotinic acetylcholine receptor with high affinity. Implications for Alzheimer's disease pathology. J Biol Chem. 2000; 275:5626–5632). How do the authors coordinate their results/ideas with these data?
The English language of the manuscript requires improvement.
Author Response
Thank you very much for your valuable comments. Below are our responses.
Point 1: QUESTION It is an interesting and well documented study addressing the pharmacokinetics of HAEE peptide administered in vivo. The idea of using this peptide to prevent amyloid-beta aggregation in the brain is quite relevant. A principal question, which is not even mentioned in the manuscript, is that the main target of amyloid-beta in the brain is considered to be alpha7 nAChR (Parri HR, Dineley KT. Nicotinic acetylcholine receptor interaction with β-amyloid: molecular, cellular, and physiological consequences. Curr Alzheimer Res. 2010; 7( 1): 27-39; Wang HY, Lee DH, D'Andrea MR, Peterson PA, Shank RP, Reitz AB. β-Amyloid 1–42 binds to α7 nicotinic acetylcholine receptor with high affinity. Implications for Alzheimer's disease pathology. J Biol Chem. 2000; 275:5626–5632). How do the authors coordinate their results/ideas with these data?
Response 1: We agree with the opinion of the Reviewer and in the revised manuscript, in the Discussion section (lines 449-464), we added the following paragraph, including data on the role of beta-amyloid interactions with the alpha7 nicotinic acetylcholine receptor:
It can be assumed that Aβ deposition induces degeneration of cholinergic terminals [25], especially at the locations of α4β2 nAChRs [26,27] and a7 nAChRs [28]. Many studies support the notion that Aβ can physically interact with α4β2 nAChRs and α7 nAChRs in various model systems [29-32]. Since Aβ accumulates in the brain regions enriched in α4β2 nAChRs and α7 nAChRs, the selective vulnerability of the hippocampus to Aβ toxicity can be associated with the high-affinity interaction between Aβ and these nAChRs [33-36]. The Ab - α4β2 nAChR interaction interface is formed by sites 11-EVHH-14 and 35-HAEE-38 of Ab and α4 subunit of α4β2 nAChR, respectively [5]. The 11-EVHH-14 region of Aβ also plays a critical role in Aβ binding to a7 nAChRs, however, the exact interface of the Ab - α7 nAChR complex is unknown [4,6,29,37,38]. The 11-EVHH-14 region has a relatively rigid backbone conformation in soluble Aβ monomers [39,40] and zinc-bound dimers [41]. This site corresponds to the b-strand b2 from the N-terminal arch of the Aβ amyloid fibrils purified from Alzheimer's brain tissue and is solvent exposed and accessible for interactions with external molecules [42]. Thus, molecular agents binding to the 11-EVHH-14 region of Aβ can modulate interactions between Aβ (in soluble or aggregated states) and α4β2- and α7-containing nAChRs.
Point 2: The English language of the manuscript requires improvement.
Response 2: After consulting with a native speaker, we made all the necessary corrections and improvements (highlighted in yellow) to the revised manuscript.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Zolotarev et al. describe the pharmacokinetics of an anti-amyloid tetrapeptide on three types of laboratory animals and model the interactions peptide-transport protein as a putative mechanism for BBB permeability.
Minor revisions:
- Combine Tables 2 and 3.
- Improve the visibility of residue names in Figures 4 - 6.
Author Response
Thank you for your attention to our work. Below are our responses.
Point 1: Combine Tables 2 and 3.
Response 1: Done.
Point 2: Improve the visibility of residue names in Figures 4 - 6
Response 2: Done.
Author Response File: Author Response.pdf
