Transnitrosylation directs TRPA1 selectivity in N-nitrosamine activators

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• S-nitrosylation regulates protein function by adding a nitrosyl group to cysteine thiols, mediating nitric oxide (NO) bioactivity.
• Transnitrosylation, the transfer of NO groups between proteins, confers selectivity in S-nitrosylation signaling pathways.
• Transient Receptor Potential (TRP) channels are sensitive to S-nitrosylation, but selective nitrosylating agents are lacking.

Purpose of the Study:

• To develop subtype-selective nitrosylating agents for TRP channels.
• To investigate the mechanism of selective TRPA1 channel activation by novel NO donors.

Main Methods:

• Synthesis of novel NO donors derived from 7-azabenzobicyclo[2.2.1]heptane (ABBH) N-nitrosamines.
• Assessing Ca(2+) influx through recombinant and native TRPA1 channels.
• Investigating the role of cysteine residues and NO scavenging in channel activation.

Main Results:

• Novel ABBH N-nitrosamines, including NNO-ABBH1, selectively activated TRPA1 channels without releasing NO.
• Activation involved S-nitrosylation of TRPA1 proteins, evidenced by cysteine mutation studies and lack of NO scavenging effect.
• Potency correlated with N-NO bond reactivity and molecular recognition of the ABBH moiety.

Conclusions:

• ABBH N-nitrosamines confer subtype selectivity to S-nitrosylation of TRP channels.
• Activation involves a synergistic mechanism of cysteine transnitrosylation and molecular recognition.
• These compounds represent a new class of selective chemical tools for studying TRPA1 channel function.