Cnn3 regulates neural tube morphogenesis and neuronal stem cell properties

Abstract

Calponin 3 (Cnn3) is a member of the Cnn family of actin-binding molecules that is highly expressed in the mammalian brain and has been shown to control dendritic spine morphology, density, and plasticity by regulating actin cytoskeletal reorganization and dynamics. However, little is known about the role of Cnn3 during embryonic development. In this study, we analyzed mutant animals deficient in Cnn3 to gain a better understanding of its role in brain morphogenesis. Embryos lacking Cnn3 exhibited massive malformation of the developing brain including exoencephaly, closure defects at the rostral neural tube, and strong enlargement of brain tissue. In wild-type animals, we found Cnn3 being localized to the apical lining of the neuroepithelium in close vicinity to beta-Catenin and N-cadherin. By performing immunohistochemistry on beta-Catenin and p-Smad, and furthermore taking advantage of Wnt-reporter animals, we provide evidence that the loss of Cnn3 during development can affect signaling pathways crucial for correct morphogenesis of the neural tube. In addition, we used embryonic neurosphere cultures to investigate the role of Cnn3 in embryonic neuronal stem cells (NSC). Here, we observed that Cnn3 deficiency in NSCs increased the number of newly formed neurospheres and increased neurosphere size without perturbing their differentiation potential. Together, our study provides evidence for an important role of Cnn3 during development of the embryonic brain and in regulating NSC function.

Calponin-3 deficiency augments contractile activity, plasticity, fibrogenic response and Yap/Taz transcriptional activation in lens epithelial cells and explants

“…TGF-β has similarly been shown to mediate crosstalk between Yap/Taz transcription and Wnt signaling and induce EMT and fibrogenic response 51 . Although deficiency of CNN3 is reported to induce neuronal stem cell proliferation via increased nuclear translocation of β-catenin and Wnt activation 15 , we did not detect nuclear translocation of β-catenin in lens epithelial cells and explants.…”

“…The C-terminal domain of CNN-3 is longer than those of CNN1 and CNN2 13 . Calponin isoforms reveal cell-type and tissue-specific distribution; with CNN1 being expressed only in smooth muscle tissues while CNN2 and CNN3 are expressed in both smooth muscle and non-muscle tissues, and CNN3 being expressed abundantly in the brain tissues 13,15,16 . CNN3 is recognized as a downstream target gene of Otx2 transcription factor which is required for eye development 17 .…”

“…Calponins are known to be serine/threonine phosphorylated by various kinases including protein kinase C, Ca 2+ /calmodulin kinase II, Rho kinase (CNN3) and MEKK1 (CNN3), with phosphorylation being reported to decrease actin interaction and suppression of the inhibitory effect of calponin on myosin Mg 2+ ATPase activity 13,[18][19][20][21][22] . CNN3 has been shown to be involved in trophoblast cell fusion, wound healing and neural tube morphogenesis largely through its role in actin cytoskeletal organization 15,22,23 . A definitive role has also been recently demonstrated for CNN3 in regulating contractile activity and force generation in different types of cells 21,24 .Our recent cDNA microarray and RNA-seq based analysis of gene expression profiles of neonatal and adult mouse lenses revealed relatively high level expression of acidic calponin (CNN3) with little to no expression of basic (CNN1) and neutral (CNN2) calponin isoforms 25 .…”

Calponin-3 is critical for coordinated contractility of actin stress fibers

“…Cnn2 knockout mice are viable, but display defects in the proliferation and migration of macrophages, neutrophils and monocytes 24 , 25 . In contrary, Cnn3 is essential for embryonic development and viability of mice 23 , 26 . The precise functions of Cnn2 and Cnn3 in non-muscle cells remain somewhat controversial.…”

Genome-wide Studies Reveal the Essential and Opposite Roles of ARID1A in Controlling Human Cardiogenesis and Neurogenesis from Pluripotent Stem Cells

“…Pervious study showed that disruption of Arid1a-DNA interaction by a single mutation (Arid1aV 1068G/V1068G ) [15] in mouse caused neural tube defects including open head folds, neural tube closure defects, and heart defects such as trabeculation defects, hypoplastic myocardial walls and ventricular septal defects. Although it was not defined whether the neural tube closure defects in Arid1aV 1068G/V1068G mouse was due to increased neurogenesis, it was previously reported that increased number of neural stem cells led to defective neural tube closure [48][49][50].…”