Global fungal-host interactome mapping identifies host targets of candidalysin

Candidalysin, a cytolytic peptide toxin secreted by the human fungal pathogen Candida albicans, is critical for fungal pathogenesis. Yet, its intracellular targets have not been extensively mapped. Here, we performed a high-throughput enhanced yeast two-hybrid (HT-eY2H) screen to map the interactome of all eight Ece1 peptides with their direct human protein targets and identified a list of potential interacting proteins, some of which were shared between the peptides. CCNH, a regulatory subunit of the CDK-activating kinase (CAK) complex involved in DNA damage repair, was identified as one of the host targets of candidalysin. Mechanistic studies revealed that candidalysin triggers a significantly increased double-strand DNA breaks (DSBs), as evidenced by the formation of γ-H2AX foci and colocalization of CCNH and γ-H2AX. Importantly, candidalysin binds directly to CCNH to activate CAK to inhibit DNA damage repair pathway. Loss of CCNH alleviates DSBs formation under candidalysin treatment. Depletion of candidalysin-encoding gene fails to induce DSBs and stimulates CCNH upregulation in a murine model of oropharyngeal candidiasis. Collectively, our study reveals that a secreted fungal toxin acts to hijack the canonical DNA damage repair pathway by targeting CCNH and to promote fungal infection.

[Prognostic significance of the changes of elastic fibers in acinar predominant or papillary-predominant pulmonary adenocarcinomas]

OBJECTIVE

To evaluate the role of elastic fiber changes in predicting survival outcomes in intermediate-grade lung adenocarcinoma.

METHODS

All pulmonary adenocarcinoma resections conducted between January 2009 and December 2009 were reviewed. Pathologically confirmed adenocarcinomas smaller than 3 cm were included in the present study. All cases were categorized into three elastic fiber patterns (EFP): complete loss as pattern Ⅰ (EFP Ⅰ), partial loss as pattern Ⅱ (EFP Ⅱ), normal and diffusely increase as pattern Ⅲ (EFP Ⅲ). Patients with different EFP were compared.

RESULTS

One hundred and ninety four patients were included in this study, with 67(34.5%), 70(36.1%)and 57(29.4%) cases presenting as EFP Ⅰ, EFP Ⅱ, and EFP Ⅲ, respectively. Lymph nodal metastases occurred in 35.8% (24/67), 40.0% (28/70), and 10.5% (6/57) of EFP Ⅰ, EFP Ⅱ and EFP Ⅲ patterns, respectively. The percentage of EFP Ⅰ and Ⅱ increased with increasing tumor size, these patterns occurring in 55.1% (38/69) of tumors ≤2.0 cm, and 79.2% (99/125) of tumors 2.1-3.0 cm in sizes, respectively. The overall 5-year overall survival rate was 75.8%, and 67.2% for EFP I, 68.6% for EFP II, and 94.7% for EFP Ⅲ.

CONCLUSION

In patients with intermediate-grade lung adenocarcinoma, EFP should be formally recognized as a feature of tumor invasion, and its evaluation can help to recognize tumor invasive and access clinical prognosis.