cCMP and cUMP occur in vivo

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Signaling

Background:

• Mammalian cells are known to contain cyclic pyrimidine nucleotides, cyclic CMP (cCMP) and cyclic UMP (cUMP).
• The in vivo occurrence and physiological relevance of these cyclic nucleotides as potential second messengers remain largely uncharacterized.

Purpose of the Study:

• To unequivocally demonstrate the in vivo presence of cyclic CMP (cCMP) and cyclic UMP (cUMP) in mammalian systems.
• To investigate the distribution of cCMP and cUMP in various organs and their response to external stimuli.

Main Methods:

• Quantification of nucleoside 3',5'-cyclic monophosphates using high-performance liquid chromatography quadrupole tandem mass spectrometry (HPLC-MS/MS).
• Confirmation of molecular identity using high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS).
• Intratracheal infection model in mice using Pseudomonas aeruginosa engineered to express the ExoY nucleotidyl cyclase toxin.

Main Results:

• Cyclic CMP (cCMP) was detected in all studied organs, with notable concentrations in the pancreas, spleen, and female reproductive system.
• Cyclic UMP (cUMP) was not detected in baseline organ samples, potentially due to mass spectrometry sensitivity limitations and matrix effects.
• Intratracheal infection with Pseudomonas aeruginosa significantly elevated cUMP levels in the lungs, serum, urine, and feces.
• The presence and identity of both cCMP and cUMP were rigorously confirmed by mass spectrometry.

Conclusions:

• This study provides the first definitive evidence for the in vivo occurrence of both cyclic CMP (cCMP) and cyclic UMP (cUMP) in mammals.
• The findings suggest that cCMP is constitutively present in various tissues, while cUMP levels can be significantly modulated by bacterial infection.
• These cyclic pyrimidine nucleotides represent novel signaling molecules with potential roles in mammalian physiology and disease.