scholarly journals Primary cilia as the nexus of biophysical and hedgehog signaling at the tendon enthesis

2020 ◽  
Vol 6 (44) ◽  
pp. eabc1799
Author(s):  
Fei Fang ◽  
Andrea G. Schwartz ◽  
Emily R. Moore ◽  
McKenzie E. Sup ◽  
Stavros Thomopoulos
Keyword(s):  
Primary Cilium ◽  
Therapeutic Target ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Surgical Repair ◽  
Failure Rates ◽  
Muscle Forces ◽  
Signal Transducers ◽  
Hh Signaling

The tendon enthesis is a fibrocartilaginous tissue critical for transfer of muscle forces to bone. Enthesis pathologies are common, and surgical repair of tendon to bone is plagued by high failure rates. At the root of these failures is a gap in knowledge of how the tendon enthesis is formed and maintained. We tested the hypothesis that the primary cilium is a hub for transducing biophysical and hedgehog (Hh) signals to regulate tendon enthesis formation and adaptation to loading. Primary cilia were necessary for enthesis development, and cilia assembly was coincident with Hh signaling and enthesis mineralization. Cilia responded inversely to loading; increased loading led to decreased cilia and decreased loading led to increased cilia. Enthesis responses to loading were dependent on Hh signaling through cilia. Results imply a role for tendon enthesis primary cilia as mechanical responders and Hh signal transducers, providing a therapeutic target for tendon enthesis pathologies.

scholarly journals KIF14 controls ciliogenesis via regulation of Aurora A and is important for Hedgehog signaling

2020 ◽  
Vol 219 (6) ◽  
Author(s):  
Petra Pejskova ◽  
Madeline Louise Reilly ◽  
Lucia Bino ◽  
Ondrej Bernatik ◽  
Linda Dolanska ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Primary Cilium ◽  
Hedgehog Signaling ◽  
Cell Cycle Progression ◽  
Primary Cilia ◽  
Aurora A ◽  
Pathway Activation ◽  
Cilia Formation ◽  
Tightly Coupled ◽  
Hh Signaling

Primary cilia play critical roles in development and disease. Their assembly and disassembly are tightly coupled to cell cycle progression. Here, we present data identifying KIF14 as a regulator of cilia formation and Hedgehog (HH) signaling. We show that RNAi depletion of KIF14 specifically leads to defects in ciliogenesis and basal body (BB) biogenesis, as its absence hampers the efficiency of primary cilium formation and the dynamics of primary cilium elongation, and disrupts the localization of the distal appendage proteins SCLT1 and FBF1 and components of the IFT-B complex. We identify deregulated Aurora A activity as a mechanism contributing to the primary cilium and BB formation defects seen after KIF14 depletion. In addition, we show that primary cilia in KIF14-depleted cells are defective in response to HH pathway activation, independently of the effects of Aurora A. In sum, our data point to KIF14 as a critical node connecting cell cycle machinery, effective ciliogenesis, and HH signaling.

scholarly journals Roles of the Primary Cilium Component Polaris in Synchondrosis Development

2009 ◽  
Vol 88 (6) ◽  
pp. 545-550 ◽  
Author(s):  
T. Ochiai ◽  
M. Nagayama ◽  
T. Nakamura ◽  
T. Morrison ◽  
D. Pilchak ◽  
...  
Keyword(s):  
Primary Cilium ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Cranial Base ◽  
Indian Hedgehog ◽  
Intramembranous Ossification ◽  
Endochondral Bone ◽  
Chondrocyte Maturation ◽  
Mouse Mutants ◽  
Patched 1

Primary cilia regulate several developmental processes and mediate hedgehog signaling. To study their roles in cranial base development, we created conditional mouse mutants deficient in Polaris, a critical primary cilium component, in cartilage. Mutant post-natal cranial bases were deformed, and their synchondrosis growth plates were disorganized. Expression of Indian hedgehog, Patched-1, collagen X, and MMP-13 was reduced and accompanied by decreases in endochondral bone. Interestingly, there was excessive intramembranous ossification along the perichondrium, accompanied by excessive Patched-1 expression, suggesting that Ihh distribution was wider and responsible for such excessive response. Indeed, expression of heparan sulfate proteoglycans (HS-PGs), normally involved in restricting hedgehog distribution, was barely detectable in mutant synchondroses. Analyses of the data provides further evidence for the essential roles of primary cilia and hedgehog signaling in cranial base development and chondrocyte maturation, and point to a close interdependence between cilia and HS-PGs to delimit targets of hedgehog action in synchondroses.

scholarly journals The novel ciliogenesis regulator DYRK2 governs Hedgehog signaling during mouse embryogenesis

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Saishu Yoshida ◽  
Katsuhiko Aoki ◽  
Ken Fujiwara ◽  
Takashi Nakakura ◽  
Akira Kawamura ◽  
...  
Keyword(s):  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Molecular Mechanisms ◽  
The Novel ◽  
Mammalian Development ◽  
Hh Signaling ◽  
Functional Analyses ◽  
First Time ◽  
Insight Into

Mammalian Hedgehog (Hh) signaling plays key roles in embryogenesis and uniquely requires primary cilia. Functional analyses of several ciliogenesis-related genes led to the discovery of the developmental diseases known as ciliopathies. Hence, identification of mammalian factors that regulate ciliogenesis can provide insight into the molecular mechanisms of embryogenesis and ciliopathy. Here, we demonstrate that DYRK2 acts as a novel mammalian ciliogenesis-related protein kinase. Loss of Dyrk2 in mice causes suppression of Hh signaling and results in skeletal abnormalities during in vivo embryogenesis. Deletion of Dyrk2 induces abnormal ciliary morphology and trafficking of Hh pathway components. Mechanistically, transcriptome analyses demonstrate down-regulation of Aurka and other disassembly genes following Dyrk2 deletion. Taken together, the present study demonstrates for the first time that DYRK2 controls ciliogenesis and is necessary for Hh signaling during mammalian development.

scholarly journals Glypican-5 stimulates rhabdomyosarcoma cell proliferation by activating Hedgehog signaling

2011 ◽  
Vol 192 (4) ◽  
pp. 691-704 ◽  
Author(s):  
Fuchuan Li ◽  
Wen Shi ◽  
Mariana Capurro ◽  
Jorge Filmus
Keyword(s):  
Cell Proliferation ◽  
Heparan Sulfate ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Core Protein ◽  
Stimulatory Activity ◽  
Rhabdomyosarcoma Cell ◽  
Hh Signaling ◽  
Patched 1

Glypican-5 (GPC5) is one of the six members of the glypican family. It has been previously reported that GPC5 stimulates the proliferation of rhabdomyosarcoma cells. In this study, we show that this stimulatory activity of GPC5 is a result of its ability to promote Hedgehog (Hh) signaling. We have previously shown that GPC3, another member of the glypican family, inhibits Hh signaling by competing with Patched 1 (Ptc1) for Hh binding. Furthermore, we showed that GPC3 binds to Hh through its core protein but not to Ptc1. In this paper, we demonstrate that GPC5 increases the binding of Sonic Hh to Ptc1. We also show that GPC5 binds to both Hh and Ptc1 through its glycosaminoglycan chains and that, unlike GPC3, GPC5 localizes to the primary cilia. Interestingly, we found that the heparan sulfate chains of GPC5 display a significantly higher degree of sulfation than those of GPC3. Based on these results, we propose that GPC5 stimulates Hh signaling by facilitating/stabilizing the interaction between Hh and Ptc1.

scholarly journals Transient primary cilia mediate robust Hedgehog pathway-dependent cell cycle control

2019 ◽  
Author(s):  
Emily K. Ho ◽  
Anaïs E. Tsai ◽  
Tim Stearns
Keyword(s):  
Cell Cycle ◽  
Primary Cilium ◽  
Primary Cilia ◽  
Cell Cycle Control ◽  
Proliferating Cells ◽  
Pathway Activity ◽  
Cell Cycles ◽  
Medulloblastoma Cell Line ◽  
Multiple Cell ◽  
Hh Signaling

SummaryThe regulation of proliferation is one of the primary functions of Hedgehog (Hh) signaling in development. Transduction of Hh signaling requires the primary cilium, a microtubule-based organelle that is necessary for several steps in the pathway (Corbit et al., 2005; Huangfu and Anderson, 2005; Huangfu et al., 2003; Liu et al., 2005; Rohatgi et al., 2007). Many cells only build a primary cilium upon cell cycle arrest in G0. In those proliferating cells that do make a cilium, it is a transient organelle, being assembled in G1 and disassembled sometime after, although exactly when is not well-characterized (Ford et al., 2018; Pugacheva et al., 2007; Wang and Dynlacht, 2018). Thus the requirement for primary cilia presents a conundrum: how are proliferative signals conveyed through an organelle that is present for only part of the cell cycle? Here we investigate this question in a mouse medulloblastoma cell line, SMB55, that requires cilium-mediated Hh pathway activity for proliferation (Zhao et al., 2015). We show that SMB55 cells are often ciliated beyond G1 into S phase, and the presence of the cilium determines the periods of Hh pathway activity. Using live imaging over multiple cell cycles, we define two windows of opportunity for Hh pathway activity, either of which is sufficient to effect cell cycle entry. The first is in the ciliated phase of the previous cell cycle, and the second is in G1 of the cell cycle in which the decision is made. We propose that the ability of cells to integrate Hh pathway activity from more than one cell cycle imparts robustness on Hh pathway control of proliferation and may have implications for other Hh-mediated events in development.

scholarly journals EMT programs promote basal mammary stem cell and tumor-initiating cell stemness by inducing primary ciliogenesis and Hedgehog signaling

2017 ◽  
Vol 114 (49) ◽  
pp. E10532-E10539 ◽  
Author(s):  
Vincent J. Guen ◽  
Tony E. Chavarria ◽  
Cornelia Kröger ◽  
Xin Ye ◽  
Robert A. Weinberg ◽  
...  
Keyword(s):  
Hedgehog Signaling ◽  
Adult Stem Cells ◽  
Primary Cilia ◽  
Epithelial Mesenchymal Transition ◽  
Mammary Epithelium ◽  
Mammary Tissue ◽  
Small Subset ◽  
Tumor Initiating Cells ◽  
Mesenchymal Transition ◽  
Hh Signaling

Tissue regeneration relies on adult stem cells (SCs) that possess the ability to self-renew and produce differentiating progeny. In an analogous manner, the development of certain carcinomas depends on a small subset of tumor cells, called “tumor-initiating cells” (TICs), with SC-like properties. Mammary SCs (MaSCs) reside in the basal compartment of the mammary epithelium, and their neoplastic counterparts, mammary TICs (MaTICs), are thought to serve as the TICs for the claudin-low subtype of breast cancer. MaSCs and MaTICs both use epithelial–mesenchymal transition (EMT) programs to acquire SC properties, but the mechanism(s) connecting EMT programs to stemness remain unclear. Here we show that this depends on primary cilia, which are nonmotile, cell-surface structures that serve as platforms for receiving cues and enable activation of various signaling pathways. We show that MaSC and MaTIC EMT programs induce primary cilia formation and Hedgehog (Hh) signaling, which has previously been implicated in both MaSC and MaTIC function. Moreover, ablation of these primary cilia is sufficient to repress Hh signaling, the stemness of MaSCs, and the tumor-forming potential of MaTICs. Together, our findings establish primary ciliogenesis and consequent Hh signaling as a key mechanism by which MaSC and MaTIC EMT programs promote stemness and thereby support mammary tissue outgrowth and tumors of basal origin.

scholarly journals Disruption of Dhcr7 and Insig1/2 in cholesterol metabolism causes defects in bone formation and homeostasis through primary cilium formation

Bone Research ◽  
2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Akiko Suzuki ◽  
Kenichi Ogata ◽  
Hiroki Yoshioka ◽  
Junbo Shim ◽  
Christopher A. Wassif ◽  
...  
Keyword(s):  
Bone Formation ◽  
Primary Cilium ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Cilium Formation ◽  
Intracellular Cholesterol

AbstractHuman linkage studies suggest that craniofacial deformities result from either genetic mutations related to cholesterol metabolism or high-cholesterol maternal diets. However, little is known about the precise roles of intracellular cholesterol metabolism in the development of craniofacial bones, the majority of which are formed through intramembranous ossification. Here, we show that an altered cholesterol metabolic status results in abnormal osteogenesis through dysregulation of primary cilium formation during bone formation. We found that cholesterol metabolic aberrations, induced through disruption of either Dhcr7 (which encodes an enzyme involved in cholesterol synthesis) or Insig1 and Insig2 (which provide a negative feedback mechanism for cholesterol biosynthesis), result in osteoblast differentiation abnormalities. Notably, the primary cilia responsible for sensing extracellular cues were altered in number and length through dysregulated ciliary vesicle fusion in Dhcr7 and Insig1/2 mutant osteoblasts. As a consequence, WNT/β-catenin and hedgehog signaling activities were altered through dysregulated primary cilium formation. Strikingly, the normalization of defective cholesterol metabolism by simvastatin, a drug used in the treatment of cholesterol metabolic aberrations, rescued the abnormalities in both ciliogenesis and osteogenesis in vitro and in vivo. Thus, our results indicate that proper intracellular cholesterol status is crucial for primary cilium formation during skull formation and homeostasis.

scholarly journals Cell-autonomous activation of Hedgehog signaling inhibits brown adipose tissue development

2015 ◽  
Vol 112 (16) ◽  
pp. 5069-5074 ◽  
Author(s):  
LaGina Nosavanh ◽  
Da-Hai Yu ◽  
Eric J. Jaehnig ◽  
Qiang Tong ◽  
Lanlan Shen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Brown Adipose ◽  
Adipose Tissue Development ◽  
Poorly Differentiated ◽  
Hh Signaling

Although recent studies have shown that brown adipose tissue (BAT) arises from progenitor cells that also give rise to skeletal muscle, the developmental signals that control the formation of BAT remain largely unknown. Here, we show that brown preadipocytes possess primary cilia and can respond to Hedgehog (Hh) signaling. Furthermore, cell-autonomous activation of Hh signaling blocks early brown-preadipocyte differentiation, inhibits BAT formation in vivo, and results in replacement of neck BAT with poorly differentiated skeletal muscle. Finally, we show that Hh signaling inhibits BAT formation partially through up-regulation of chicken ovalbumin upstream promoter transcription factor II (COUP-TFII). Taken together, our studies uncover a previously unidentified role for Hh as an inhibitor of BAT development.

scholarly journals Motile cilia of human airway epithelia contain hedgehog signaling components that mediate noncanonical hedgehog signaling

2018 ◽  
Vol 115 (6) ◽  
pp. 1370-1375 ◽  
Author(s):  
Suifang Mao ◽  
Alok S. Shah ◽  
Thomas O. Moninger ◽  
Lynda S. Ostedgaard ◽  
Lin Lu ◽  
...  
Keyword(s):  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Contact Point ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Airway Epithelial Cells ◽  
Airway Epithelial ◽  
Airway Epithelia ◽  
Hh Signaling ◽  
Motile Cilia

Differentiated airway epithelia produce sonic hedgehog (SHH), which is found in the thin layer of liquid covering the airway surface. Although previous studies showed that vertebrate HH signaling requires primary cilia, as airway epithelia mature, the cells lose primary cilia and produce hundreds of motile cilia. Thus, whether airway epithelia have apical receptors for SHH has remained unknown. We discovered that motile cilia on airway epithelial cells have HH signaling proteins, including patched and smoothened. These cilia also have proteins affecting cAMP-dependent signaling, including Gαi and adenylyl cyclase 5/6. Apical SHH decreases intracellular levels of cAMP, which reduces ciliary beat frequency and pH in airway surface liquid. These results suggest that apical SHH may mediate noncanonical HH signaling through motile cilia to dampen respiratory defenses at the contact point between the environment and the lung, perhaps counterbalancing processes that stimulate airway defenses.

scholarly journals ERICH3 in Primary Cilia Regulates Cilium Formation and the Localisations of Ciliary Transport and Sonic Hedgehog Signaling Proteins

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mona Alsolami ◽  
Stefanie Kuhns ◽  
Manal Alsulami ◽  
Oliver E. Blacque
Keyword(s):  
Sonic Hedgehog ◽  
Primary Cilium ◽  
Molecular Motors ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Intraflagellar Transport ◽  
Retrograde Transport ◽  
Signaling Proteins ◽  
Sonic Hedgehog Signaling ◽  
And Function

Abstract Intraflagellar transport (IFT) is essential for the formation and function of the microtubule-based primary cilium, which acts as a sensory and signalling device at the cell surface. Consisting of IFT-A/B and BBSome cargo adaptors that associate with molecular motors, IFT transports protein into (anterograde IFT) and out of (retrograde IFT) the cilium. In this study, we identify the mostly uncharacterised ERICH3 protein as a component of the mammalian primary cilium. Loss of ERICH3 causes abnormally short cilia and results in the accumulation of IFT-A/B proteins at the ciliary tip, together with reduced ciliary levels of retrograde transport regulators, ARL13B, INPP5E and BBS5. We also show that ERICH3 ciliary localisations require ARL13B and BBSome components. Finally, ERICH3 loss causes positive (Smoothened) and negative (GPR161) regulators of sonic hedgehog signaling (Shh) to accumulate at abnormally high levels in the cilia of pathway-stimulated cells. Together, these findings identify ERICH3 as a novel component of the primary cilium that regulates cilium length and the ciliary levels of Shh signaling molecules. We propose that ERICH3 functions within retrograde IFT-associated pathways to remove signaling proteins from cilia.

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