Role of Escherichia coli endopeptidases and dd-carboxypeptidases in infection and regulation of innate immune response

Expression of Carboxypeptidase X M14 Family Member 2 Accelerates the Progression of Hepatocellular Carcinoma via Regulation of the gp130/JAK2/Stat1 Pathway

Background

Carboxypeptidase X, M14 family member 2 (CPXM2) has been reported to be involved with several human malignancies. However, the impact of CPXM2 on human hepatocellular carcinoma (HCC) tumorigenesis has not been studied.

Materials and Methods

Using immunohistochemistry, the detailed CPXM2 expression patterns were examined in HCC cell lines and tissues. Additionally, a hepatic stellate cell line overexpressing CPXM2 and an HCC CPXM2-knockdown cell line were established by lipofection of an expression plasmid or short hairpin RNA, respectively. The transfection efficiencies were confirmed by reverse transcription-quantitative PCR, Western blotting and immunofluorescence. Moreover, Western blotting was conducted to determine the phosphorylation levels of the tyrosine kinase 2 (JAK2)/signal transducer and activator of transcription 3 (Stat1) pathway. Furthermore, gp130-specific hairpin RNA was used to knockdown gp130 expression in hepatic stellate cells overexpressing CPXM2. The malignant phenotype of cultured HCC cells was assessed by a Cell Counting Kit-8 (CCK8) assay, plate cloning assay, Matrigel invasion assay and wound-healing assay in vitro.

Results

It was demonstrated that CPXM2 was upregulated in HCC, and its upregulation predicted a poor prognosis. Besides, the upregulation of CPXM2 markedly enhanced the metastatic potential of HCC via the gp130/JAK2/Stat1 signaling pathway in vitro.

Conclusion

In summary, this evidence suggests a positive role for CPXM2 in HCC progression via modulation of the gp130/JAK2/Stat1 signaling pathway in HCC.

Comparative Analysis of Peptidoglycans From Pseudomonas aeruginosa Isolates Recovered From Chronic and Acute Infections

Pseudomonas aeruginosa is one of the first causes of acute nosocomial and chronic infections in patients with underlying respiratory pathologies such as cystic fibrosis (CF). It has been proposed that P. aeruginosa accumulates mutations driving to peptidoglycan modifications throughout the development of the CF-associated infection, as a strategy to lower the immune detection hence ameliorating the chronic persistence. As well, some studies dealing with peptidoglycan modifications driving to a better survival within the host have been published in other gram-negatives. According to these facts, the gram-negative peptidoglycan could be considered as a pathogen-associated molecular pattern with very important implications regarding the host’s detection-response, worthy to dissect in detail. For this reason, in this work we characterized for the first time the peptidoglycans of three large collections [early CF, late CF and acute infection (bloodstream) P. aeruginosa strains] from qualitative (HPLC), quantitative and inflammatory capacity-related perspectives. The final goal was to identify composition trends potentially supporting the cited strategy of evasion/resistance to the immune system and providing information regarding the differential intrinsic adaptation depending on the type of infection. Although we found several punctual strain-specific particularities, our results indicated a high degree of inter-collection uniformity in the peptidoglycan-related features and the absence of trends amongst the strains studied here. These results suggest that the peptidoglycan of P. aeruginosa is a notably conserved structure in natural isolates regardless of transitory changes that some external conditions could force. Finally, the inverse correlation between the relative amount of stem pentapeptides within the murein sacculus and the resistance to immune lytic attacks against the peptidoglycan was also suggested by our results. Altogether, this work is a major step ahead to understand the biology of peptidoglycan from P. aeruginosa natural strains, hopefully useful in future for therapeutic alternatives design.