Mesenchymal Sufu Regulates Development of Mandibular Molars via Shh Signaling

2019 ◽  
Vol 98 (12) ◽  
pp. 1348-1356 ◽  
Author(s):  
J. Li ◽  
J. Xu ◽  
Y. Cui ◽  
L. Wang ◽  
B. Wang ◽  
...  

Sonic hedgehog ( Shh) in dental epithelium regulates tooth morphogenesis by epithelial-mesenchymal signaling transduction. However, the action of Shh signaling regulation in this process is not well understood. Here we find that mesenchymal Suppressor of Fused ( Sufu), a major negative regulator of Shh signaling, plays an important role in modulating the tooth germ morphogenesis during the bud-to-cap stage transition. Deletion of Sufu in dental mesenchyme by Dermo1-Cre mice leads to delayed development of mandibular molar into cap stage with defect of primary enamel knot (EK) formation. We show the disruption of cell proliferation and programmed cell death in dental epithelium and mesenchyme in Sufu mutants. Epithelial-specific adhesion molecule E-cadherin is evidently reduced in the bilateral basal cells of tooth germ at E14.5. The cells in the presumptive EK, predominantly expressing P-cadherin, appear stratified but fail to condense. Moreover, the transcripts of primary EK marker genes, including Shh, Fgf4, and p21, are significantly decreased compared to controls. In contrast, we find that deficiency of Sufu results in elevation of Shh signaling in mesenchyme, indicated by the significant upregulation of Gli1 and Ptch1. Meanwhile, the expression of Bmp4 and Fgf3, the critical factors of mesenchymal-epithelial induction, is significantly inhibited in dental mesenchyme. Furthermore, the expression of Runx2 experiences a transient decrease at the bud stage. Taken together, these data suggest that mesenchymal Sufu is necessary for tuning the Shh signaling, which may act as an upstream modulator of Bmp4 and Fgf3 to coordinate the interplay between the dental mesenchyme and epithelium of tooth germ.

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Hirofumi Noguchi ◽  
Jesse Garcia Castillo ◽  
Kinichi Nakashima ◽  
Samuel J Pleasure

Adult hippocampal neurogenesis requires the quiescent neural stem cell (NSC) pool to persist lifelong. However, establishment and maintenance of quiescent NSC pools during development is not understood. Here, we show that Suppressor of Fused (Sufu) controls establishment of the quiescent NSC pool during mouse dentate gyrus (DG) development by regulating Sonic Hedgehog (Shh) signaling activity. Deletion of Sufu in NSCs early in DG development decreases Shh signaling activity leading to reduced proliferation of NSCs, resulting in a small quiescent NSC pool in adult mice. We found that putative adult NSCs proliferate and increase their numbers in the first postnatal week and subsequently enter a quiescent state towards the end of the first postnatal week. In the absence of Sufu, postnatal expansion of NSCs is compromised, and NSCs prematurely become quiescent. Thus, Sufu is required for Shh signaling activity ensuring expansion and proper transition of NSC pools to quiescent states during DG development.


2018 ◽  
Author(s):  
Hirofumi Noguchi ◽  
Jesse Garcia Castillo ◽  
Kinichi Nakashima ◽  
Samuel J. Pleasure

AbstractAdult hippocampal neurogenesis requires the quiescent neural stem cell (NSC) pool to persist lifelong. The establishment and maintenance of quiescent NSC pools during development is not understood. Here we show that Suppressor of Fused (Sufu) controls establishment of the quiescent NSC pool during mouse dentate gyrus (DG) development through regulation of Sonic Hedgehog (Shh) signaling. Deletion of Sufuin NSCs at the beginning of DG development decreases Shh signaling leading to reduced proliferation of NSCs, resulting in a small quiescent NSC pool in adult mice. We found that putative adult NSCs proliferate and increase their numbers in the first postnatal week and subsequently become quiescent towards the end of the first postnatal week. In the absence of Sufu, postnatal expansion of NSCs is compromised, and NSCs prematurely become quiescent. Thus, Sufu is required for Shh signaling activity ensuring the expansion and proper transition of NSC pools to quiescence during DG development.


Development ◽  
2000 ◽  
Vol 127 (7) ◽  
pp. 1431-1443 ◽  
Author(s):  
Y. Zhang ◽  
Z. Zhang ◽  
X. Zhao ◽  
X. Yu ◽  
Y. Hu ◽  
...  

The murine tooth development is governed by sequential and reciprocal epithelial-mesenchymal interactions. Multiple signaling molecules are expressed in the developing tooth germ and interact each other to mediate the inductive tissue interactions. Among them are Sonic hedgehog (SHH), Bone Morphogenetic Protein-2 (BMP2) and Bone Morphogenetic Protein-4 (BMP4). We have investigated the interactions between these signaling molecules during early tooth development. We found that the expression of Shh and Bmp2 is downregulated at E12.5 and E13.5 in the dental epithelium of the Msx1 mutant tooth germ where Bmp4 expression is significantly reduced in the dental mesenchyme. Inhibition of BMP4 activity by noggin resulted in repression of Shh and Bmp2 in wild-type dental epithelium. When implanted into the dental mesenchyme of Msx1 mutants, beads soaked with BMP4 protein were able to restore the expression of both Shh and Bmp2 in the Msx1 mutant epithelium. These results demonstrated that mesenchymal BMP4 represents one component of the signal acting on the epithelium to maintain Shh and Bmp2 expression. In contrast, BMP4-soaked beads repressed Shh and Bmp2 expression in the wild-type dental epithelium. TUNEL assay indicated that this suppression of gene expression by exogenous BMP4 was not the result of an increase in programmed cell death in the tooth germ. Ectopic expression of human Bmp4 to the dental mesenchyme driven by the mouse Msx1 promoter restored Shh expression in the Msx1 mutant dental epithelium but repressed Shh in the wild-type tooth germ in vivo. We further demonstrated that this regulation of Shh expression by BMP4 is conserved in the mouse developing limb bud. In addition, Shh expression was unaffected in the developing limb buds of the transgenic mice in which a constitutively active Bmpr-IB is ectopically expressed in the forelimb posterior mesenchyme and throughout the hindlimb mesenchyme, suggesting that the repression of Shh expression by BMP4 may not be mediated by BMP receptor-IB. These results provide evidence for a new function of BMP4. BMP4 can act upstream to Shh by regulating Shh expression in mouse developing tooth germ and limb bud. Taken together, our data provide insight into a new regulatory mechanism for Shh expression, and suggest that this BMP4-mediated pathway in Shh regulation may have a general implication in vertebrate organogenesis.


2020 ◽  
Vol 21 (5) ◽  
pp. 1587 ◽  
Author(s):  
Akihiro Hosoya ◽  
Nazmus Shalehin ◽  
Hiroaki Takebe ◽  
Tsuyoshi Shimo ◽  
Kazuharu Irie

Sonic hedgehog (Shh) is a secreted protein with important roles in mammalian embryogenesis. During tooth development, Shh is primarily expressed in the dental epithelium, from initiation to the root formation stages. A number of studies have analyzed the function of Shh signaling at different stages of tooth development and have revealed that Shh signaling regulates the formation of various tooth components, including enamel, dentin, cementum, and other soft tissues. In addition, dental mesenchymal cells positive for Gli1, a downstream transcription factor of Shh signaling, have been found to have stem cell properties, including multipotency and the ability to self-renew. Indeed, Gli1-positive cells in mature teeth appear to contribute to the regeneration of dental pulp and periodontal tissues. In this review, we provide an overview of recent advances related to the role of Shh signaling in tooth development, as well as the contribution of this pathway to tooth homeostasis and regeneration.


Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1353
Author(s):  
A. Denise R. Garcia

The Sonic hedgehog (Shh) molecular signaling pathway is well established as a key regulator of neurodevelopment. It regulates diverse cellular behaviors, and its functions vary with respect to cell type, region, and developmental stage, reflecting the incredible pleiotropy of this molecular signaling pathway. Although it is best understood for its roles in development, Shh signaling persists into adulthood and is emerging as an important regulator of astrocyte function. Astrocytes play central roles in a broad array of nervous system functions, including synapse formation and function as well as coordination and orchestration of CNS inflammatory responses in pathological states. Neurons are the source of Shh in the adult, suggesting that Shh signaling mediates neuron–astrocyte communication, a novel role for this multifaceted pathway. Multiple roles for Shh signaling in astrocytes are increasingly being identified, including regulation of astrocyte identity, modulation of synaptic organization, and limitation of inflammation. This review discusses these novel roles for Shh signaling in regulating diverse astrocyte functions in the healthy brain and in pathology.


2012 ◽  
Vol 91 (7) ◽  
pp. 690-695 ◽  
Author(s):  
Y. Wang ◽  
L. Li ◽  
Y. Zheng ◽  
G. Yuan ◽  
G. Yang ◽  
...  

Several Bmp genes are expressed in the developing mouse tooth germ from the initiation to the late-differentiation stages, and play pivotal roles in multiple steps of tooth development. In this study, we investigated the requirement of BMP activity in early tooth development by transgenic overexpression of the extracellular BMP antagonist Noggin. We show that overexpression of Noggin in the dental epithelium at the tooth initiation stage arrests tooth development at the lamina/early-bud stage. This phenotype is coupled with a significantly reduced level of cell proliferation rate and a down-regulation of Cyclin-D1 expression, specifically in the dental epithelium. Despite unaltered expression of genes known to be implicated in early tooth development in the dental mesenchyme and dental epithelium of transgenic embryos, the expression of Pitx2, a molecular marker for the dental epithelium, became down-regulated, suggesting the loss of odontogenic fate in the transgenic dental epithelium. Our results reveal a novel role for BMP signaling in the progression of tooth development from the lamina stage to the bud stage by regulating cell proliferation and by maintaining odontogenic fate of the dental epithelium.


2018 ◽  
Vol 48 (6) ◽  
pp. 456-464 ◽  
Author(s):  
Jin Sug Kim ◽  
Kyung Sook Cho ◽  
Seon Hwa Park ◽  
Sang Ho Lee ◽  
Ji Hwan Lee ◽  
...  

Background: Peritoneal fibrosis is a devastating complication of peritoneal dialysis. However, its precise mechanism is unclear, and specific treatments have not yet been established. Recent evidence suggests that the sonic hedgehog (SHH) signaling pathway is involved in tissue fibrogenesis. Drugs that inhibit this pathway are emerging in the field of anti-fibrosis therapy. Itraconazole, an anti-fungal agent, was also recently recognized as an inhibitor of the SHH signaling pathway. In this study, we used a mouse model to investigate whether the SHH signaling pathway is involved in the development of peritoneal fibrosis and the effects of itraconazole on peritoneal fibrosis. Methods: Peritoneal fibrosis was induced by intraperitoneal (IP) injection of 0.1% chlorhexidine gluconate (CG) solution every other day for 4 weeks, with or without itraconazole treatment (20 mg/kg, IP injection on a daily basis). Male C57BL/6 mice were divided into 4 groups: saline group, saline plus itraconazole group, CG group, and CG plus itraconazole group. Isotonic saline was administered intraperitoneally to the control group. The peritoneal tissues were evaluated for histological changes, expression of fibrosis markers, and the main components of the SHH signaling pathway. Results: Peritoneal thickening was evident in the CG group and was significantly decreased by itraconazole administration (80.4 ± 7.7 vs. 28.2 ± 3.8 µm, p < 0.001). The expression of the following SHH signaling pathway components was upregulated in the CG group and suppressed by itraconazole treatment: SHH, patched, smoothened, and glioma-associated oncogene transcription factor 1. The IP injection of CG solution increased the expression of fibrosis markers such as α-smooth muscle actin and transforming growth factor-β1 in the peritoneal tissues. Itraconazole treatment significantly decreased the expression of these markers. Conclusion: Our study provides the first evidence that the SHH signaling pathway may be implicated in peritoneal fibrosis. It also demonstrates that itraconazole treatment has protective effects on peritoneal fibrosis through the regulation of the SHH signaling pathway. These findings suggest that blockage of the SHH signaling pathway is a potential therapeutic strategy for peritoneal fibrosis.


2020 ◽  
Author(s):  
Carian Jägers ◽  
Henk Roelink

AbstractBirth defects due to congenital errors in enzymes involved cholesterol synthesis like Smith-Lemli-Opitz syndrome (SLOS) and Lathosterolosis cause an accumulation of cholesterol precursors and a deficit in cholesterol. The phenotype of both SLOS and Lathosterolosis have similarities to syndromes associated with abnormal Sonic hedgehog (Shh) signaling, consistent with the notion that impaired cholesterol signaling can cause reduced Shh signaling. Two multipass membrane proteins play central roles in Shh signal transduction, the putative Resistance, Nodulation and Division (RND) antiporters Ptch1 and Ptch2, and the G-protein coupled receptor Smoothened (Smo). Sterols have been suggested as cargo for Ptch1, while Smo activity can affected both positively and negatively by steroidal molecules. We demonstrate that mESCs mutant for 7-dehydroxycholesterol reductase (7dhcr) or sterol-C5-desaturase (sc5d) reduce the Hh response in nearby wildtype cells when grown in mosaic organoids. This non-cell autonomous inhibitory activity of the mutant cells required the presence of both Ptch1 and Ptch2. These observations support a model in which late cholesterol precursors that accumulate in cells lacking 7DHCR are the cargo for Ptch1 and Ptch2 activity that mediates the non-cell autonomous inhibition of Smo.


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