BNP signaling is crucial for embryonic stem cell proliferation.
BACKGROUND
Embryonic stem (ES) cells have unlimited proliferation potential, and can differentiate into several cell types, which represent ideal sources for cell-based therapy. This high-level proliferative ability is attributed to an unusual type of cell cycle. The Signaling pathways that regulate the proliferation of ES cells are of great interest.


RESULTS
In this study, we show that murine ES cells specifically express brain natriuretic peptide (BNP), and its signaling is essential for ES cell proliferation. We found that BNP and its receptor (NPR-A, natriuretic peptide receptor-A) were highly expressed in self-renewing murine ES cells, whereas the levels were markedly reduced after ES cell differentiation by the withdrawal of LIF. Targeting of BNP with short interfering RNA (siRNA) resulted in the inhibition of ES cell proliferation, as indicated by a marked reduction in the cell number and colony size, a significant reduction in DNA synthesis, and decreased numbers of cells in S phase. BNP knockdown in ES cells led to the up-regulation of gamma-aminobutyric acid receptor A (GABA(A)R) genes, and activation of phosphorylated histone (gamma-H2AX), which negatively affects ES cell proliferation. In addition, knockdown of BNP increased the rate of apoptosis and reduced the expression of the transcription factor Ets-1.


CONCLUSIONS
Appropriate BNP expression is essential for the maintenance of ES cell propagation. These findings establish BNP as a novel endogenous regulator of ES cell proliferation.
Abdelalim
Essam Mohamed
EM
Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Japan. essam@belle.shiga-med.ac.jp
Tooyama
Ikuo
I
D000818:Animals; D017209:Apoptosis; D001483:Base Sequence; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism; D002453:Cell Cycle; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000096:biosynthesis; D017931:DNA Primers / Q000235:genetics; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism*; D015870:Gene Expression; D051379:Mice; D008954:Models, Biological; D020097:Natriuretic Peptide, Brain / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism; D050784:Proto-Oncogene Protein c-ets-1 / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D017461:Receptors, Atrial Natriuretic Factor / Q000235:genetics / Q000378:metabolism; D011963:Receptors, GABA-A / Q000235:genetics; D015398:Signal Transduction; D000099242:Atrial Natriuretic Factor Receptor B
D006152:Cyclic GMP; D017931:DNA Primers; D020097:Natriuretic Peptide, Brain; D050784:Proto-Oncogene Protein c-ets-1; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017461:Receptors, Atrial Natriuretic Factor; D011963:Receptors, GABA-A; D000099242:Atrial Natriuretic Factor Receptor B; C494042:Ets1 protein, mouse; C058930:brain natriuretic peptide receptor; C091715:atrial natriuretic factor receptor A