Loss of Ccbe1 affects cardiac-specification and cardiomyocyte differentiation in mouse embryonic stem cells

Space microgravity increases expression of genes associated with proliferation and differentiation in human cardiac spheres

Efficient generation of cardiomyocytes from human-induced pluripotent stem cells (hiPSCs) is important for their application in basic and translational studies. Space microgravity can significantly change cell activities and function. Previously, we reported upregulation of genes associated with cardiac proliferation in cardiac progenitors derived from hiPSCs that were exposed to space microgravity for 3 days. Here we investigated the effect of long-term exposure of hiPSC-cardiac progenitors to space microgravity on global gene expression. Cryopreserved 3D hiPSC-cardiac progenitors were sent to the International Space Station (ISS) and cultured for 3 weeks under ISS microgravity and ISS 1 G conditions. RNA-sequencing analyses revealed upregulation of genes associated with cardiac differentiation, proliferation, and cardiac structure/function and downregulation of genes associated with extracellular matrix regulation in the ISS microgravity cultures compared with the ISS 1 G cultures. Gene ontology analysis and Kyoto Encyclopedia of Genes and Genomes mapping identified the upregulation of biological processes, molecular function, cellular components, and pathways associated with cell cycle, cardiac differentiation, and cardiac function. Taking together, these results suggest that space microgravity has a beneficial effect on the differentiation and growth of cardiac progenitors.

[High expression of CCBE1 in adjacent tissues of tongue squamous cell carcinoma is correlated with pericancerous lymphatic vessel proliferation and poor 5-year survival outcomes]

OBJECTIVE

To examine the correlation of CCBE1 expression in adjacent tissues of tongue squamous cell carcinoma (TSCC) with pericancerous lymphatic vessel proliferation, cervical lymph node metastasis and survival outcomes of the patients.

METHODS

Lymphatic vessel density was quantified in pericancerous tissue sections of 44 cases of cT1-2N0 TSCC using D2-40 as the lymphatic vessel endothelial marker for calibration and counting of the lymphatic vessels. Of these 44 cases, 22 showed a relatively low lymphatic vessel density (group A) and the other 22 had a high lymphatic vessel density (group B), and the expression levels of CCBE1 in the adjacent tissues determined using immunohistochemistry, immunofluorescence assay and Western blotting were compared between the two groups. The expression level of CCBE1 was also measured in another 90 patients with TSCC using immunohistochemistry, and all the patients were followed up for their survival outcomes.

RESULTS

Immunohistochemistry and Western blotting showed a significantly lower rate of high CCBE1 expression in group A than in group B (P < 0.05). Immunofluorescence assay showed co-localization of CCBE1 and D2-40 in the adjacent tissues of TSCC. In the 90 TSCC patients with complete follow-up data, a high expression of CCBE1 was found to correlate with lymph node metastasis and a poor 5-year survival outcomes of the patients (P < 0.05).

CONCLUSION

A high expression of CCBE1 in the adjacent tissues of TSCC is closely related with pericancerous lymphatic vessel proliferation, cervical lymph node metastasis and a poor 5-year survival of the patients, suggesting the value of CCBE1 as a potential prognostic predictor for TSCC.

CCBE1 in Cardiac Development and Disease

The collagen- and calcium-binding EGF-like domains 1 (CCBE1) is a secreted protein extensively described as indispensable for lymphangiogenesis during development enhancing VEGF-C signaling. In human patients, mutations in CCBE1 have been found to cause Hennekam syndrome, an inherited disease characterized by malformation of the lymphatic system that presents a wide variety of symptoms such as primary lymphedema, lymphangiectasia, and heart defects. Importantly, over the last decade, an essential role for CCBE1 during heart development is being uncovered. In mice, Ccbe1 expression was initially detected in distinct cardiac progenitors such as first and second heart field, and the proepicardium. More recently, Ccbe1 expression was identified in the epicardium and sinus venosus (SV) myocardium at E11.5–E13.5, the stage when SV endocardium–derived (VEGF-C dependent) coronary vessels start to form. Concordantly, CCBE1 is required for the correct formation of the coronary vessels and the coronary artery stem in the mouse. Additionally, Ccbe1 was found to be enriched in mouse embryonic stem cells (ESC) and revealed as a new essential gene for the differentiation of ESC-derived early cardiac precursor cell lineages. Here, we bring an up-to-date review on the role of CCBE1 in cardiac development, function, and human disease implications. Finally, we envisage the potential of this molecule’s functions from a regenerative medicine perspective, particularly novel therapeutic strategies for heart disease.

DAND5 Inactivation Enhances Cardiac Differentiation in Mouse Embryonic Stem Cells

Deciphering the clues of a regenerative mechanism for the mammalian adult heart would save millions of lives in the near future. Heart failure due to cardiomyocyte loss is still one of the significant health burdens worldwide. Here, we show the potential of a single molecule, DAND5, in mouse pluripotent stem cell-derived cardiomyocytes specification and proliferation. Dand5 loss-of-function generated the double of cardiac beating foci compared to the wild-type cells. The early formation of cardiac progenitor cells and the increased proliferative capacity of Dand5 KO mESC-derived cardiomyocytes contribute to the observed higher number of derived cardiac cells. Transcriptional profiling sequencing and quantitative RT-PCR assays showed an upregulation of early cardiac gene networks governing cardiomyocyte differentiation, cell cycling, and cardiac regenerative pathways but reduced levels of genes involved in cardiomyocyte maturation. These findings prompt DAND5 as a key driver for the generation and expansion of pluripotent stem cell-derived cardiomyocytes systems with further clinical application purposes.