The Effect of LRAP on Enamel Organ Epithelial Cell Differentiation

2007 ◽  
Vol 86 (11) ◽  
pp. 1095-1099 ◽  
Author(s):  
T.Q. Le ◽  
Y. Zhang ◽  
W. Li ◽  
P.K. DenBesten

Leucine-rich amelogenin peptide (LRAP) is an alternatively spliced amelogenin found in the developing enamel organ. LRAP functions to regulate the development of mesenchymal-derived cells; however, its effect on cells of the enamel organ remains unclear. The hypothesis tested in this study is that LRAP also regulates human enamel organ epithelial cells. Recombinant human LRAP (rH58) was synthesized in E. coli, purified, and exogenously added to cultures of human primary enamel epithelial cells, which were analyzed for changes in cell proliferation and differentiation. rH58 had no effect on cell proliferation, but altered enamel epithelial cell morphology, resulting in larger, more rounded cells. Immunofluorescence showed that rH58 treatment increased amelogenin synthesis, but down-regulated Notch1 expression in enamel epithelial cells. LAMP-1, a membrane receptor for LRAP in mesenchymal cells, was identified and was up-regulated in the presence of rH58. These results suggest that rH58 promotes differentiation of human enamel organ epithelial cells.

2022 ◽  
Author(s):  
Wenguang Yin ◽  
Andreas Liontos ◽  
Janine Koepke ◽  
Maroua Ghoul ◽  
Luciana Mazzocchi ◽  
...  

The tracheal epithelium is a primary target for pulmonary diseases as it provides a conduit for air flow between the environment and the lung lobes. The cellular and molecular mechanisms underlying airway epithelial cell proliferation and differentiation remain poorly understood. Hedgehog (Hh) signaling orchestrates communication between epithelial and mesenchymal cells in the lung, where it modulates stromal cell proliferation, differentiation and signaling back to the epithelium. Here, we reveal a new, autocrine function of Hh signaling in airway epithelial cells. Epithelial cell depletion of the ligand Sonic hedgehog (SHH) or its effector Smoothened (SMO) causes defects in both epithelial cell proliferation and differentiation. In cultured primary human airway epithelial cells, Hh signaling inhibition also hampers cell proliferation and differentiation. Epithelial Hh function is mediated, at least in part, through transcriptional activation as Hh signaling inhibition leads to downregulation of cell-type specific transcription factor genes in both the mouse trachea and human airway epithelial cells. These results provide new insights into the role of Hh signaling in epithelial cell proliferation and differentiation during airway development.


2007 ◽  
Vol 361-363 ◽  
pp. 1075-1078
Author(s):  
Michiyo Honda ◽  
Shigeki Izumi ◽  
Nobuyuki Kanzawa ◽  
Takahide Tsuchiya ◽  
Mamoru Aizawa

Appropriate culture conditions cause bone marrow stem cells to differentiate into multilineage cells such as adipocytes, chondrocytes, and osteoblasts. One key factor that regulates intercellular signaling and cell differentiation is the extracellular matrix microenvironment. The composition of the extracellular matrix influences cellular functions. In the present study, we investigated the effects of a microenvironment comprising a three-dimensional apatite-fiber scaffold (AFS) that has two kinds of pores (micro- and macro pores) on proliferation and subsequent differentiation of bone marrow stem cells. Morphologic observation revealed that osteoblastic cells in the AFS were distributed primarily in the same location on the fibrous scaffold and formed bridges within micro- and macro pores. We used molecular approaches to evaluate cell proliferation and differentiation in detail. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that culturing bone marrow cells on AFS increases expression of osteocalcin (OC) mRNA compared with culture in a dish. Furthermore, cells cultured in AFS expressed type X collagen (Col X), which is a marker of hypertrophic cartilage. These data suggest that the three-dimensional microenvironment of AFS facilitates cell proliferation and differentiation, and promotes endochondral ossification of bone marrow cells.


1992 ◽  
Vol 263 (2) ◽  
pp. C343-C347 ◽  
Author(s):  
V. Quemener ◽  
Y. Blanchard ◽  
D. Lescoat ◽  
R. Havouis ◽  
J. P. Moulinoux

Polyamines (PA), polycations present in all mammalian cells, are essential for cell proliferation and differentiation. In vitro, PA are known to bind to DNA with a high affinity. In vivo, the intimate association of endogenous PA with highly condensed chromatin has been reported. During spermatogenesis, when processes of cell proliferation and differentiation take place, the potential role of polyamines has not been studied in depth. We report here the PA levels measured in human spermatogenic cell nuclei at different stages of differentiation. Cell populations (spermatocytes and round, elongating, or elongated spermatids) were obtained after submitting human testes to a trypsin-deoxyribonuclease digestion, then to a centrifugal elutriation and Percoll gradient centrifugation. A significant and progressive nuclear spermine level decrease was observed from primary spermatocytes to elongated spermatids. This release of spermine from nuclei was concomitant with three major events in mammalian spermiogenesis: the reduction of DNA transcription activity, the replacement of histone proteins by protamines, and the compaction of chromatin. This is the first report arguing a release of nuclear spermine during an in vivo physiological cell differentiation process.


2011 ◽  
Vol 301 (2) ◽  
pp. L187-L196 ◽  
Author(s):  
Guang Yang ◽  
Maurice D. Hinson ◽  
Jessica E. Bordner ◽  
Qing S. Lin ◽  
Amal P. Fernando ◽  
...  

Postnatal lung development requires proliferation and differentiation of specific cell types at precise times to promote proper alveolar formation. Hyperoxic exposure can disrupt alveolarization by inhibiting cell growth; however, it is not fully understood how this is mediated. The transcription factor CCAAT/enhancer binding protein-α (C/EBPα) is highly expressed in the lung and plays a role in cell proliferation and differentiation in many tissues. After 72 h of hyperoxia, C/EBPα expression was significantly enhanced in the lungs of newborn mice. The increased C/EBPα protein was predominantly located in alveolar type II cells. Silencing of C/EBPα with a transpulmonary injection of C/EBPα small interfering RNA (siRNA) prior to hyperoxic exposure reduced expression of markers of type I cell and differentiation typically observed after hyperoxia but did not rescue the altered lung morphology at 72 h. Nevertheless, when C/EBPα hyperoxia-exposed siRNA-injected mice were allowed to recover for 2 wk in room air, lung epithelial cell proliferation was increased and lung morphology was restored compared with hyperoxia-exposed control siRNA-injected mice. These data suggest that C/EBPα is an important regulator of postnatal alveolar epithelial cell proliferation and differentiation during injury and repair.


2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Ying Li ◽  
Eun Ha Choi ◽  
Ihn Han

Recently, a growing body of evidence has shown the role of reactive species as secondary messengers in cell proliferation and differentiation, as opposed to the harmful metabolism byproducts that they were previously solely recognized as. Thus, the balance of intracellular reduction-oxidation (redox) homeostasis plays a vital role in the regulation of stem cell self-renewal and differentiation. Nonthermal biocompatible plasma (NBP) has emerged as a novel tool in biomedical applications. Recently, NBP has also emerged as a powerful tool in the tissue engineering field for the surface modification of biomaterial and the promotion of stem cell differentiation by the regulation of intracellular redox biology. NBP can generate various kinds of reactive oxygen species (ROS) and reactive nitrogen species (RNS), which may play the role of the second passenger in the cell signaling network and active antioxidant system in cells. Herein, we review the current knowledge on mechanisms by which NBP regulates cell proliferation and differentiation through redox modification. Considering the importance of redox homeostasis in the regulation of stem cell differentiation, understanding the underlying molecular mechanisms involved will provide important new insights into NBP-induced stem cell differentiation for tissue engineering.


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