NLRP3 activation contributes to endothelin-1-induced erectile dysfunction.

Area of Science:

• Urology
• Immunology
• Physiology

Background:

• Endothelin-1 (ET-1) is implicated in erectile dysfunction.
• The role of Nucleotide Oligomerization Domain-Like Receptor Family, Pyrin Domain Containing 3 (NLRP3) inflammasome in ET-1-induced erectile dysfunction is not fully understood.

Purpose of the Study:

• To investigate the role of ET receptors (ET_A and ET_B) and NLRP3 inflammasome activation in ET-1-induced erectile dysfunction in mice.

Main Methods:

• Functional assays measuring intracavernosal pressure (ICP/MAP) and smooth muscle relaxation in mouse corpora cavernosa (CC).
• Immunoblotting assays to assess protein expression (caspase-1).
• Pharmacological inhibition of ET receptors (BQ123, BQ788), NLRP3 (MCC950), calcium (BAPTA AM), and ROS (tiron).
• Studies in wild-type (WT), NLRP3 knockout (NLRP3^-/-), and caspase knockout (caspase^-/-) mice.

Main Results:

• ET-1 reduced ICP/MAP and impaired CC relaxation in WT mice.
• NLRP3 inhibition (MCC950), ET_A antagonism (BQ123), ET_B antagonism (BQ788), calcium chelation (BAPTA AM), and ROS scavenging (tiron) all reversed ET-1-induced erectile dysfunction.
• ET-1 increased caspase-1 expression in CC, which was prevented by BQ123 and NLRP3 genetic deletion.
• BQ788 increased caspase-1 and IL-1β levels, while BQ123 diminished caspase-1 expression.
• BAPTA AM blocked ET-1-induced ROS generation.

Conclusions:

• ET-1-induced erectile dysfunction in mice is mediated by the activation of both ET_A and ET_B receptors.
• This activation leads to calcium-dependent reactive oxygen species (ROS) generation, subsequently activating the NLRP3 inflammasome in the corpus cavernosum.
• Targeting ET receptors, NLRP3, calcium, or ROS pathways may offer therapeutic strategies for ET-1-related erectile dysfunction.