Dual action of Dooku1 on PIEZO1 channel in human red blood cells

by Selleckchem | Dec 04 2023

PIEZO1 is a mechanosensitive non-selective cation channel, present in many cell types including Red Blood Cells (RBCs). Together with the Gárdos channel, PIEZO1 forms in RBCs a tandem that participates in the rapid adjustment of the cell volume. The pharmacology allowing functional studies of the roles of PIEZO1 has only recently been developed, with Yoda1 as a widely used PIEZO1 agonist. In 2018, Yoda1 analogues were developed, as a step towards an improved understanding of PIEZO1 roles and functions. Among these, Dooku1 was the most promising antagonist of Yoda1-induced effects, without having any ability to activate PIEZO1 channels. Since then, Dooku1 has been used in various cell types to antagonize Yoda1 effects. In the present study using RBCs, Dooku1 shows an apparent IC50 on Yoda1 effects of 90.7 µM, one order of magnitude above the previously reported data on other cell types. Unexpectedly, it was able, by itself, to produce entry of calcium sufficient to trigger Gárdos channel activation. Moreover, Dooku1 evoked a rise in intracellular sodium concentrations, suggesting that it targets a non-selective cation channel. Dooku1 effects were abolished upon using GsMTx4, a known mechanosensitive channel blocker, indicating that Dooku1 likely targets PIEZO1. Our observations lead to the conclusion that Dooku1 behaves as a PIEZO1 agonist in the RBC membrane, similarly to Yoda1 but with a lower potency. Taken together, these results show that the pharmacology of PIEZO1 in RBCs must be interpreted with care especially due to the unique characteristics of RBC membrane and associated cytoskeleton.

Comments:

The passage you provided discusses the properties and effects of PIEZO1, a mechanosensitive non-selective cation channel, and its interaction with specific agonists and antagonists such as Yoda1 and Dooku1. Here's a summary of the key points mentioned in the passage:

1. **PIEZO1 Channel**: PIEZO1 is a mechanosensitive non-selective cation channel found in various cell types, including Red Blood Cells (RBCs). It plays a role in the rapid adjustment of cell volume, in conjunction with the Gárdos channel.

2. **Yoda1**: Yoda1 is a widely used agonist of PIEZO1. It activates PIEZO1 channels and has been an essential tool in studying the function of PIEZO1.

3. **Dooku1**: Dooku1 is an analogue of Yoda1. Unlike Yoda1, Dooku1 acts as an antagonist of Yoda1-induced effects and does not activate PIEZO1 channels. It has been used in various cell types to counteract the effects of Yoda1.

4. **Study Findings**: In the context of RBCs, Dooku1 was found to have an apparent IC50 of 90.7 µM on Yoda1 effects, which is higher than previously reported data in other cell types. Unexpectedly, Dooku1 alone was able to induce calcium entry, triggering the activation of the Gárdos channel. Additionally, Dooku1 led to an increase in intracellular sodium concentrations, suggesting its interaction with a non-selective cation channel.

5. **Mechanism of Action**: The study indicated that Dooku1 likely targets PIEZO1 in RBCs. This conclusion was supported by the fact that the effects of Dooku1 were abolished when GsMTx4, a known mechanosensitive channel blocker, was used. Therefore, Dooku1 behaves as a PIEZO1 agonist in RBC membranes, similar to Yoda1, although with lower potency.

6. **Interpretation Caution**: The unique characteristics of RBC membranes and associated cytoskeleton make the interpretation of PIEZO1 pharmacology in RBCs challenging. The study emphasizes the need for careful interpretation when studying the pharmacological effects of PIEZO1 in RBCs due to these unique properties.

In summary, the study suggests that Dooku1, initially characterized as a PIEZO1 antagonist, behaves as a PIEZO1 agonist in RBCs, activating the channel but with lower potency compared to Yoda1. These findings highlight the complexity of PIEZO1 pharmacology and the importance of considering cell type-specific responses when studying its functions and interactions with pharmacological agents.