Differential proteomics of monosodium urate crystals-induced inflammatory response in dissected murine air pouch
Chih-Wei Chiu1, Han-Min Chen2, Tzong-Ta Wu2
1Department of Chemistry, National Taiwan Normal University, Taipei 116, Taiwan.
Abstract:
The precipitation of monosodium urate crystals within joints triggers an acute inflammatory reaction that is the root cause of gout. The inflammation induced by the injection of MSU crystals into the murine air pouch for 1, 3, and 5 h was examined by iTRAQ-based proteomic profiling. The iTRAQ-labeled peptides were fractionated by SCX, basic-RP or solution-IEF, followed by LC-MS/MS analysis. A total of 951 proteins were quantified from the total combined fractions. Among them, 317 proteins exhibited a differential expression, compared to that of the controls at one time point or more. The majority of the differentially expressed proteins were found in the sample after a 5-h MSU treatment. Western blot revealed that the expression levels of cathelin-related antimicrobial peptide and S100A9 were positively correlated with the time-course treated with MSU. Further analysis of GeneGO pathway demonstrated that these differentially expressed proteins are primarily related to the immune-related complement system and the tricarboxylic acid cycle. Moreover, seven genes from the TCA cycle were found to be significantly downregulated at the transcriptional level and its correlation with gout and possible therapeutic applications are worth further investigation. Last, we found that pyruvate carboxylation could be potential targets for antigout treatment.
Insights
Monosodium urate (MSU) crystal-induced gout inflammation involves significant protein expression changes, particularly in immune and metabolic pathways. Pyruvate carboxylation emerges as a potential therapeutic target for gout treatment.
Area of Science:
- Biochemistry
- Immunology
- Proteomics
Background:
- Gout is caused by monosodium urate (MSU) crystal precipitation in joints, triggering acute inflammation.
- Understanding the molecular mechanisms of MSU-induced inflammation is crucial for developing effective gout therapies.
Purpose of the Study:
- To investigate the proteomic changes associated with MSU crystal-induced inflammation in a murine air pouch model.
- To identify key biological pathways and potential therapeutic targets involved in gout pathogenesis.
Main Methods:
- iTRAQ-based proteomic profiling of murine air pouch lavage fluid after MSU crystal injection at 1, 3, and 5 hours.
- Peptide fractionation using SCX, basic-RP, and solution-IEF, followed by LC-MS/MS analysis.
- Western blot validation and pathway analysis (GeneGO).
Main Results:
- Quantification of 951 proteins, with 317 showing differential expression compared to controls.
- Most significant changes observed at 5 hours post-MSU treatment.
- Differentially expressed proteins are linked to the complement system and tricarboxylic acid (TCA) cycle; seven TCA cycle genes were downregulated.
- Cathelin-related antimicrobial peptide and S100A9 expression correlated with MSU treatment time.
Conclusions:
- MSU crystal-induced inflammation involves complex proteomic alterations, particularly affecting immune and metabolic pathways.
- Downregulation of TCA cycle genes suggests a metabolic component in gout pathogenesis.
- Pyruvate carboxylation represents a promising therapeutic target for antigout interventions.
