Dusp1 regulates thermal tolerance limits in zebrafish by maintaining mitochondrial integrity.

Temperature tolerance restricts the distribution of a species. However, the molecular and cellular mechanisms that set the thermal tolerance limits of an organism are poorly understood. Here, we report on the function of dual-specificity phosphatase 1 (DUSP1) in thermal tolerance regulation. Notably, we found that dusp1 -/- zebrafish grew normally but survived within a narrowed temperature range. The higher susceptibility of these mutant fish to both cold and heat challenges was attributed to accelerated cell death caused by aggravated mitochondrial dysfunction and over-production of reactive oxygen species in the gills. The DUSP1-MAPK-DRP1 axis was identified as a key pathway regulating these processes in both fish and human cells. These observations suggest that DUSP1 may play a role in maintaining mitochondrial integrity and redox homeostasis. We therefore propose that maintenance of cellular redox homeostasis may be a key mechanism for coping with cellular thermal stress and that the interplay between signaling pathways regulating redox homeostasis in the most thermosensitive tissue (i.e., gills) may play an important role in setting the thermal tolerance limit of zebrafish.

Study on the correlation between extracellular matrix protein-1 and the growth, metastasis and angiogenesis of laryngeal carcinoma.

OBJECTIVE: To investigate the correlation between extracellular matrix protein-1 (ECM1) and the growth, metastasis and angiogenesis of laryngeal carcinoma. MATERIALS AND METHODS: Forty-five samples with laryngeal benign and malignant tumors confirmed by pathology in Laiwu City People's Hospital from March 2006 to March 2011 were collected, in which there were 29 cases with laryngeal carcinoma and 16 with benign tumors. The expression of ECM1 and factor VIII-related antigens in patients with laryngeal carcinoma and those with benign tumors was respectively detected using immunohistochemical method, and the correlation between ECM1 staining grade and microvessel density (MVD) was analyzed. RESULTS: In laryngeal carcinoma tissue, ECM1 was mainly expressed in cytoplasm, less in cytomembrane or intercellular substance. With abundant expression in the tissue of laryngeal benign tumors (benign mesenchymoma and hemangioma), ECM1 was primarily expressed in the connective tissue, which was different from the expression in laryngeal carcinoma tissue. The proportion of positive ECM1 staining (++) in patients with laryngeal carcinoma was dramatically higher than those with benign tumors (p<0.05), and that of strongly-positive ECM1 staining (+++) slightly higher. The results of Spearman nonparametric correlation analysis revealed that ECM1 staining grade in laryngeal carcinoma tissue had a significantly-positive correlation with MVD (r=0.866, p=0.000). CONCLUSIONS: ECM1 expression in laryngeal carcinoma is closely associated with tumor cell growth, metastasis and angiogenesis, which can be considered as an effective predictor in the occurrence and postoperative recurrence of laryngeal carcinoma.