Embryonic tongue morphogenesis in an organ culture model of mouse mandibular arches: blocking Sonic hedgehog signaling leads to microglossia

Galectin-3 Plays an Important Role in BMP7-Induced Cementoblastic Differentiation of Human Periodontal Ligament Cells by Interacting with Extracellular Components

Human periodontal ligament stem cells (hPDLSCs) contain multipotent postnatal stem cells that differentiate into PDL progenitors, osteoblasts, and cementoblasts. Previously, we obtained cementoblast-like cells from hPDLSCs using bone morphogenetic protein 7 (BMP7) treatment. Differentiation into appropriate progenitor cells requires interactions and changes between stem or progenitor cells and their so-called environment niches, and cell surface markers play an important role. However, cementoblast-specific cell surface markers have not yet been fully studied. Through decoy immunization with intact cementoblasts, we developed a series of monoclonal antibodies against cementoblast-specific membrane/extracellular matrix (ECM) molecules. One of these antibodies, the anti-CM3 antibody, recognized an approximate 30 kDa protein in a mouse cementoblast cell line, and the CM3 antigenic molecule accumulated in the cementum region of human tooth roots. Using mass spectrometric analysis, we found that the antigenic molecules recognized by the anti-CM3 antibody were galectin-3. As cementoblastic differentiation progressed, the expression of galectin-3 increased, and it localized at the cell surface. Inhibition of galectin-3 via siRNA and a specific inhibitor showed the complete blockage of cementoblastic differentiation and mineralization. In contrast, ectopic expression of galectin-3 induced cementoblastic differentiation. Galectin-3 interacted with laminin α2 and BMP7, and these interactions were diminished by galectin-3 inhibitors. These results suggested that galectin-3 participates in binding to the ECM component and trapping BMP7 to induce, in a sustained fashion, the upregulation of cementoblastic differentiation. Finally, galectin-3 could be a potential cementoblast-specific cell surface marker, with functional importance in cell-to-ECM interactions.

The role of Eya1 and Eya2 in the taste system of mice from embryonic stage to adulthood

Members of the Eya family, which are a class of transcription factors with phosphatase activity, are widely expressed in cranial sensory organs during development. However, it is unclear whether these genes are expressed in the taste system during development and whether they play any role in specifying taste cell fate. In this study, we report that Eya1 is not expressed during embryonic tongue development but that Eya1-expressing progenitors in somites or pharyngeal endoderm give rise to tongue musculature or taste organs, respectively. In the Eya1-deficient tongues, these progenitors do not proliferate properly, resulting in a smaller tongue at birth, impaired growth of taste papillae, and disrupted expression of Six1 in the papillary epithelium. On the other hand, Eya2 is specifically expressed in endoderm-derived circumvallate and foliate papillae located on the posterior tongue during development. In adult tongues, Eya1 is predominantly expressed in IP3R3-positive taste cells in the taste buds of the circumvallate and foliate papillae, while Eya2 is persistently expressed in these papillae at higher levels in some epithelial progenitors and at lower levels in some taste cells. We found that conditional knockout of Eya1 in the third week or Eya2 knockout reduced Pou2f3+, Six1+ and IP3R3+ taste cells. Our data define for the first time the expression patterns of Eya1 and Eya2 during the development and maintenance of the mouse taste system and suggest that Eya1 and Eya2 may act together to promote lineage commitment of taste cell subtypes.

Nuclear factor 1 X-type-associated regulation of myogenesis in developing mouse tongue

OBJECTIVES

The tongue contains skeletal myofibers that differ from those in the trunk, limbs, and other orofacial muscles. However, the molecular basis of myogenic differentiation in the tongue muscles remains unclear. In this study, we conducted comprehensive gene expression profiling of the developing murine tongue.

METHODS

Tongue primordia were dissected from mouse embryos at embryonic day (E)10.5-E18.5, while myogenic markers were detected via microarray analysis and quantitative polymerase chain reaction (PCR). In addition to common myogenic regulatory factors such as Myf5, MyoD, myogenin, and Mrf4, we focused on Nfix, which acts as a unique molecular switch triggering the shift from embryonic to fetal myoblast lineage during limb myogenesis. Nfix inhibition was performed using a specific antisense oligonucleotide in the organ culture of tongue primordia.

RESULTS

Microarray and ingenuity pathway analyses confirmed the significant upregulation of myogenic signaling molecules, including Nfix, associated with the differentiation of myoblasts from myogenic progenitor cells during E10.5-E11.5. Quantitative PCR confirmed that Nfix expression started at E10.5 and peaked at E14.5. Fetal myoblast-specific genes, such as Mck and Myh8, were upregulated after E14.5, whereas embryonic myoblast-specific genes, such as Myh3 and Myh7, were downregulated. When Nfix was inhibited in the organ culture of tongue primordia, subtle morphological differences were noted in the tongue. Such an observation was only noted in the cultures of E10.5-derived tongue primordia.

CONCLUSIONS

These results reveal the contribution of Nfix to tongue myogenesis. Nfix expression during early tongue development may play a vital role in tongue muscle development.

Gestational Intermittent Hypoxia Induces Mitochondrial Impairment in the Geniohyoid Muscle of Offspring Rats

Introduction Gestational intermittent hypoxia (IH), a hallmark of obstructive sleep apnea during gestation, alters respiratory neural control and diaphragm muscle contractile function in the offspring. The geniohyoid (GH) muscle is innervated by the respiratory-related hypoglossal nerve and plays a role in tongue traction and suckling, motor behaviors that then give way to chewing. Here, we aimed to investigate the effects of gestational exposure to IH on the muscle development and metabolism of GH and masseter muscles in male offspring rats. Materials and methods Pregnant Sprague-Dawley rats were exposed to IH (3-min periods of 4-21% O2) for eight hours/day during gestational days 7-20. The GH and masseter muscles from 35-day-old male offspring (n = 6 in each group) were analyzed.  Results Gestational IH induction reduced type IIA fiber size in the GH muscle of the offspring but not in the masseter muscle. Western blot analysis showed that gestational IH-induced significant downregulation of peroxisome proliferator-activated receptor (PPAR)-gamma coactivator 1-alpha (PGC1α) protein in the GH muscle but not in the masseter muscle. Moreover, optic atrophy 1 and mitofusin-2 proteins were decreased and mitochondrial fission 1 protein levels were increased in the GH muscle of the offspring exposed to gestational IH. Mitochondrial adenosine triphosphate (ATP) synthase subunit alpha and transcriptional factor A (TFAM) were decreased in the GH muscle post-gestational IH. Conclusion These findings suggest that gestational IH-induced impaired mitochondrial metabolism and alteration of oxidative myofibers of the GH muscle in the pre-adolescent offspring, but not the masseter muscle, owing to the susceptibility of GH muscular mitochondria to gestational IH.

Transcriptome Profile of Membrane and Extracellular Matrix Components in Ligament-Fibroblastic Progenitors and Cementoblasts Differentiated from Human Periodontal Ligament Cells

Ligament-fibroblastic cells and cementoblasts, two types of progenitor cells that differentiate from periodontal ligament stem cells (hPDLSCs), are responsible for the formation of the adhesive tissues in the tooth root. Since one of the factors that determines the fate of stem cell differentiation is the change in the microenvironment of the stem/progenitor cells, this study attempted to compare and analyze the molecular differences in the membrane and ECM of the two progenitor cells. Single cells derived from hPDLSCs were treated with TGF-β1 and BMP7 to obtain ligament-fibroblastic and cementoblastic cells, respectively. The transcriptome profiles of three independent replicates of each progenitor were evaluated using next-generation sequencing. The representative differentially expressed genes (DEGs) were verified by qRT-PCR, Western blot analysis, and immunohistochemistry. Among a total of 2245 DEGs identified, 142 and 114 DEGs related to ECM and cell membrane molecules were upregulated in ligament-fibroblastic and cementoblast-like cells, respectively. The major types of integrin and cadherin were found to be different between the two progenitor cells. In addition, the representative core proteins for each glycosaminoglycan-specific proteoglycan class were different between the two progenitors. This study provides a detailed understanding of cell–cell and cell–ECM interactions through the specific components of the membrane and ECM for ligament-fibroblastic and cementoblastic differentiation of hPDLSCs.

Anti-inflammatory and antioxidant properties of jervine, a sterodial alkaloid from rhizomes of Veratrum album

BACKGROUND

Veratrum, hellebore is an important plant species of the Liliaceae family and jervine is the characteristic steroidal alkaloid constituent of Veratrum album.

PURPOSE

In the current study, anti-inflammatory and antioxidant effects of jervine isolated from NH₄OH-benzene extract of V. album rhizomes were investigated on CAR induced paw edema in rats.

METHODS/STUDY DESIGN

In inflammatory study, 50, 100, 200 and 400  mg/kg doses of jervine, 25  mg/kg doses of DIC and IND were orally administered, and the volume of the foots were measured up to their knee arthrosis by plethismometer. After one hour of the oral administration of the all treatments, 0.1 ml of CAR solution (1%) was injected into the foot of the all rat groups and the volume of the foots were measured during 5 h after CAR injection. GPx, SOD, GR, MPO, CAT enzymes activities and GSH, LPO levels of the supernatants of paw homogenates and inflammation biomarkers such as TNF-α and IL-1β in the rats serums were also estimated.

RESULTS

According to the present results, jervine exerted 50.4-73.5% anti-inflammatory effects in carrageenan induced paw edema. Inflammation biomarkers such as TNF-α, IL-1β and MPO that increased by CAR injection were suppressed by the administrations of all doses of jervine, IND and DIC. In all paw tissues, LPO levels as indicator of oxidative tissue damage were found to be high in CAR-treated group and it was found to be decreased in all doses of jervine.

CONCLUSION

Jervine, DIC and IND reduced the negative effects of CAR due to increasing effects on the SOD, CAT, GSH, GPx and GR antioxidants.

Neural crest cells utilize primary cilia to regulate ventral forebrain morphogenesis via Hedgehog-dependent regulation of oriented cell division

Development of the brain directly influences the development of the face via both physical growth and Sonic hedgehog (SHH) activity; however, little is known about how neural crest cells (NCCs), the mesenchymal population that comprise the developing facial prominences, influence the development of the brain. We utilized the conditional ciliary mutant Wnt1-Cre;Kif3a^fl/fl to demonstrate that loss of primary cilia on NCCs resulted in a widened ventral forebrain. We found that neuroectodermal Shh expression, dorsal/ventral patterning, and amount of proliferation in the ventral neuroectoderm was not changed in Wnt1-Cre;Kif3a^fl/fl mutants; however, tissue polarity and directional cell division were disrupted. Furthermore, NCCs of Wnt1-Cre;Kif3a^fl/fl mutants failed to respond to a SHH signal emanating from the ventral forebrain. We were able to recapitulate the ventral forebrain phenotype by removing Smoothened from NCCs (Wnt1-Cre;Smo^fl/fl) indicating that changes in the ventral forebrain were mediated through a Hedgehog-dependent mechanism. Together, these data suggest a novel, cilia-dependent mechanism for NCCs during forebrain development.

Tongue and Taste Organ Biology and Function: Homeostasis Maintained by Hedgehog Signaling

The tongue is an elaborate complex of heterogeneous tissues with taste organs of diverse embryonic origins. The lingual taste organs are papillae, composed of an epithelium that includes specialized taste buds, the basal lamina, and a lamina propria core with matrix molecules, fibroblasts, nerves, and vessels. Because taste organs are dynamic in cell biology and sensory function, homeostasis requires tight regulation in specific compartments or niches. Recently, the Hedgehog (Hh) pathway has emerged as an essential regulator that maintains lingual taste papillae, taste bud and progenitor cell proliferation and differentiation, and neurophysiological function. Activating or suppressing Hh signaling, with genetic models or pharmacological agents used in cancer treatments, disrupts taste papilla and taste bud integrity and can eliminate responses from taste nerves to chemical stimuli but not to touch or temperature. Understanding Hh regulation of taste organ homeostasis contributes knowledge about the basic biology underlying taste disruptions in patients treated with Hh pathway inhibitors.