P21 is also known as cyclin-dependent kinase (CDK) inhibitor 1. It is involved in the processes of apoptosis and cell cycle arrest and has been shown to block the activity of cyclin and CDK complexes in animal modules.

A study conducted by Mavers et. Al examined the potential P21 has in use relating to synovial inflammation that is consistent in animals with rheumatoid arthritis. In a previous study, Mavers et. Al found that in animals with rheumatoid arthritis there is decreased expression of P21 throughout the synovium, leading them to conclude that P21 has a suppressant effect on the inflammatory responses of the macrophages. This alludes to the idea that in the presence of P21 there will be less inflammation and tissue breakdown in the synovium.

The researchers of the initial study induced arthritis in mice that were lacking the expression of P21. From there, the next step was to treat the P21 knockout mice with a P21 mimetic which acted as a prophylactic for the development of arthritis in the mice. In the mice treated with P21 mimetic, the use of Luminex-based assays, flow cytometry, and ELISAs were used in order to observe LPS-induced cytokines and the signal transduction pathways throughout the macrophages in order to determine the strength of the inflammatory response in the presence of the P21 mimetic.

The results of this study showed that in the mice lacking the presence of P21 had drastic development of arthritis. However, in the mice treated with the P21 mimetic the activation of the macrophages was inhibited. Since there was a reduced inflammatory response in the macrophages which led to exacerbated arthritis symptoms, the researchers concluded that the presence of P21 could potentially play a key role in treating rheumatoid arthritis (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3253189/).

Effects of P21 on Alzheimer’s Disease and Cognitive Defects

The integrity of dendritic spines is essential to proper cognitive functioning. Mental delays are frequently caused by mutations in the P21-activated kinases (PAK) due to the important role that PAK-cofilin signaling plays in the morphogenesis of the dendritic spines and regulation of actin filaments. A study conducted by Zhao et. Al examined how the PAK pathway could potentially be involved in the development of Alzheimer’s disease. It was found that in cases of Alzheimer’s Disease PAK activity was remarkably reduced which goes hand in hand with decreased phosphoPAK, pathology of cofilin proteins, and loss of the protein drebrin which is an actin-regulatory protein.

Additionally, the study found the 𝜷-amyloid (A𝜷) was directly involved in drebrin loss and defects in PAK signaling pathways in hippocampal neurons that were treated with A𝜷. Furthermore, the same defects were found in Appswe transgenic mice that possessed a double mutation leading to overproduction of A𝜷. It was also noted that in adult mice, inhibition of PAK signaling led to similar instances of cofilin pathology, loss of drebrin protein, and memory loss that is also seen in cases of Alzheimer’s disease. The findings of this study indicate that activation of the P21-activated kinase pathway can potentially protect against Alzheimer’s as well as various other forms of declining cognitive functioning (https://www.nature.com/articles/nn1630).

Peptides Prefer the Cold

In order to reduce peptide breakdown, keep peptides refrigerated at all times but DO NOT FREEZE.
Swab the top of the vial with a 95% alcohol wipe before accessing.
Only Mix with Sterile Bacteriostatic Water
Bacteriostatic water is vital to preventing contamination and preserving the stability of the compound.
Push the needle through the stopper at an angle in order to direct the stream to the side of the vial.
Reconstituted peptide solution should be stored at around 4 degrees Celsius but not frozen, while lyophilized peptide solution should be kept at -20 degrees Celsius.

P21 is sold for laboratory research use only. Terms of sale apply. Not for human consumption, nor medical, veterinary, or household uses. Please familiarize yourself with our Terms & Conditions prior to ordering.