Surrogate fostering of mice prevents prenatal estradiol-induced insulin resistance modulation of the microbiota-gut-brain axis.

Introduction: Prenatal and early postnatal development are known to influence future health. We previously reported that prenatal high estradiol (HE) exposure induces insulin resistance in male mice by disrupting hypothalamus development. Because a foster dam can modify a pup's gut microbiota and affect its health later in life, we explored whether surrogate fostering could also influence glucose metabolism in HE offspring and examined mechanisms that might be involved.

External α-carbonic anhydrase and solute carrier 4 are required for bicarbonate uptake in a freshwater angiosperm.

The freshwater monocot Ottelia alismoides is the only known species to operate three CO2-concentrating mechanisms (CCMs): constitutive bicarbonate (HCO3-) use, C4 photosynthesis, and facultative Crassulacean acid metabolism, but the mechanism of HCO3- use is unknown. We found that the inhibitor of an anion exchange protein, 4,4'-diisothio-cyanatostilbene-2,2'-disulfonate (DIDS), prevented HCO3- use but also had a small effect on CO2 uptake. An inhibitor of external carbonic anhydrase (CA), acetazolamide (AZ), reduced the affinity for CO2 uptake but also prevented HCO3- use via an effect on the anion exchange protein.

Sox2 haploinsufficiency primes regeneration and Wnt responsiveness in the mouse cochlea.

During development, Sox2 is indispensable for cell division and differentiation, yet its roles in regenerating tissues are less clear. Here, we used combinations of transgenic mouse models to reveal that Sox2 haploinsufficiency (Sox2haplo) increases rather than impairs cochlear regeneration in vivo. Sox2haplo cochleae had delayed terminal mitosis and ectopic sensory cells, yet normal auditory function.

Augmented Indian hedgehog signaling in cranial neural crest cells leads to craniofacial abnormalities and dysplastic temporomandibular joint in mice.

Extensive studies have pinpointed the crucial role of Indian hedgehog (Ihh) signaling in the development of the appendicular skeleton and the essential function of Ihh in the formation of the temporomandibular joint (TMJ). In this study, we have investigated the effect of augmented Ihh signaling in TMJ development. We took a transgenic gain-of-function approach by overexpressing Ihh in the cranial neural crest (CNC) cells using a conditional Ihh transgenic allele and the Wnt1-Cre allele.

Altered FGF Signaling Pathways Impair Cell Proliferation and Elevation of Palate Shelves.

In palatogenesis, palatal shelves are patterned along the mediolateral axis as well as the anteroposterior axis before the onset of palatal fusion. Fgf10 specifically expressed in lateral mesenchyme of palate maintains Shh transcription in lateral epithelium, while Fgf7 activated in medial mesenchyme by Dlx5, suppressed the expansion of Shh expression to medial epithelium. How FGF signaling pathways regulate the cell behaviors of developing palate remains elusive.

FGF8 signaling sustains progenitor status and multipotency of cranial neural crest-derived mesenchymal cells in vivo and in vitro.

The cranial neural crest (CNC) cells play a vital role in craniofacial development and regeneration. They are multi-potent progenitors, being able to differentiate into various types of tissues. Both pre-migratory and post-migratory CNC cells are plastic, taking on diverse fates by responding to different inductive signals.

The short stature homeobox 2 (Shox2)-bone morphogenetic protein (BMP) pathway regulates dorsal mesenchymal protrusion development and its temporary function as a pacemaker during cardiogenesis.

The atrioventricular (AV) junction plays a critical role in chamber septation and transmission of cardiac conduction pulses. It consists of structures that develop from embryonic dorsal mesenchymal protrusion (DMP) and the embryonic AV canal. Despite extensive studies on AV junction development, the genetic regulation of DMP development remains poorly understood.

BMPRIA mediated signaling is essential for temporomandibular joint development in mice.

The central importance of BMP signaling in the development and homeostasis of synovial joint of appendicular skeleton has been well documented, but its role in the development of temporomandibular joint (TMJ), also classified as a synovial joint, remains completely unknown. In this study, we investigated the function of BMPRIA mediated signaling in TMJ development in mice by transgenic loss-of- and gain-of-function approaches. We found that BMPRIA is expressed in the cranial neural crest (CNC)-derived developing condyle and glenoid fossa, major components of TMJ, as well as the interzone mesenchymal cells.

Directed Bmp4 expression in neural crest cells generates a genetic model for the rare human bony syngnathia birth defect.

Congenital bony syngnathia, a rare but severe human birth defect, is characterized by bony fusion of the mandible to the maxilla. However, the genetic mechanisms underlying this birth defect are poorly understood, largely due to limitation of available animal models. Here we present evidence that transgenic expression of Bmp4 in neural crest cells causes a series of craniofacial malformations in mice, including a bony fusion between the maxilla and hypoplastic mandible, resembling the bony syngnathia syndrome in humans.

Replacing Shox2 with human SHOX leads to congenital disc degeneration of the temporomandibular joint in mice.

The temporomandibular joint (TMJ) consists in the glenoid fossa arising from the otic capsule through intramembranous ossification, the fibrocartilaginous disc and the condyle, which is derived from the secondary cartilage by endochondral ossification. We have reported previously that cranial neural-crest-specific inactivation of the homeobox gene Shox2, which is expressed in the mesenchymal cells of the maxilla-mandibular junction and later in the progenitor cells and perichondrium of the developing chondyle, leads to dysplasia and ankylosis of the TMJ and that replacement of the mouse Shox2 with the human SHOX gene rescues the dysplastic and ankylosis phenotypes but results in a prematurely worn out articular disc. In this study, we investigate the molecular and cellular bases for the prematurely worn out articular disc in the TMJ of mice carrying the human SHOX replacement allele in the Shox2 locus (termed Shox2 (SHOX-KI/KI)).

FGF signaling sustains the odontogenic fate of dental mesenchyme by suppressing β-catenin signaling.

Odontoblasts and osteoblasts develop from multipotent craniofacial neural crest cells during tooth and jawbone development, but the mechanisms that specify and sustain their respective fates remain largely unknown. In this study we used early mouse molar and incisor tooth germs that possess distinct tooth-forming capability after dissociation and reaggregation in vitro to investigate the mechanism that sustains odontogenic fate of dental mesenchyme during tooth development. We found that after dissociation and reaggregation, incisor, but not molar, mesenchyme exhibits a strong osteogenic potency associated with robustly elevated β-catenin signaling activity in a cell-autonomous manner, leading to failed tooth formation in the reaggregates.

Generation of Shox2-Cre allele for tissue specific manipulation of genes in the developing heart, palate, and limb.

Shox2 is expressed in several developing organs in a tissue specific manner in both mice and humans, including the heart, palate, limb, and nervous system. To better understand the spatial and temporal expression patterns of Shox2 and to systematically dissect the genetic cascade regulated by Shox2, we created Shox2-LacZ and Shox2-Cre knock-in mouse lines. We show that the Shox2-LacZ allele expresses beta-galactosidase reporter gene in a fashion that recapitulates the endogenous Shox2 expression pattern in developing organs, including the sinoatrial node (SAN), the anterior portion of the palate, and the proximal region of the limb bud.

Mice with Tak1 deficiency in neural crest lineage exhibit cleft palate associated with abnormal tongue development.

Cleft palate represents one of the most common congenital birth defects in humans. TGFβ signaling, which is mediated by Smad-dependent and Smad-independent pathways, plays a crucial role in regulating craniofacial development and patterning, particularly in palate development. However, it remains largely unknown whether the Smad-independent pathway contributes to TGFβ signaling function during palatogenesis.

Mutant HSPB1 overexpression in neurons is sufficient to cause age-related motor neuronopathy in mice.

The small heat shock protein HSPB1 is a multifunctional, α-crystallin-based protein that has been shown to be neuroprotective in animal models of motor neuron disease and peripheral nerve injury. Missense mutations in HSPB1 result in axonal Charcot-Marie-Tooth disease with minimal sensory involvement (CMT2F) and distal hereditary motor neuropathy type 2 (dHMN-II). These disorders are characterized by a selective loss of motor axons in peripheral nerve resulting in distal muscle weakness and often severe disability.

Tissue interaction is required for glenoid fossa development during temporomandibular joint formation.

The mammalian temporomandibular joint (TMJ) develops from two distinct mesenchymal condensations that grow toward each other and ossify through different mechanisms, with the glenoid fossa undergoing intramembranous ossification while the condyle being endochondral in origin. In this study, we used various genetically modified mouse models to investigate tissue interaction between the condyle and glenoid fossa during TMJ formation in mice. We report that either absence or dislocation of the condyle results in an arrested glenoid fossa development.

Wnt5a regulates directional cell migration and cell proliferation via Ror2-mediated noncanonical pathway in mammalian palate development.

Tissue and molecular heterogeneities are present in the developing secondary palate along the anteroposterior (AP) axis in mice. Here, we show that Wnt5a and its receptor Ror2 are expressed in a graded manner along the AP axis of the palate. Wnt5a deficiency leads to a complete cleft of the secondary palate, which exhibits distinct phenotypic alterations at histological, cellular and molecular levels in the anterior and posterior regions of the palate.

Shox2-deficiency leads to dysplasia and ankylosis of the temporomandibular joint in mice.

The temporomandibular joint (TMJ) is a unique synovial joint whose development differs from the formation of other synovial joints. Mutations have been associated with the developmental defects of the TMJ only in a few genes. In this study, we report the expression of the homeobox gene Shox2 in the cranial neural crest derived mesenchymal cells of the maxilla-mandibular junction and later in the progenitor cells and undifferentiated chondrocytes of the condyle as well as the glenoid fossa of the developing TMJ.

Mice with an anterior cleft of the palate survive neonatal lethality.

Many genes are known to function in a region-specific manner in the developing secondary palate. We have previously shown that Shox2-deficient embryos die at mid-gestation stage and develop an anterior clefting phenotype. Here, we show that mice carrying a conditional inactivation of Shox2 in the palatal mesenchyme survive the embryonic and neonatal lethality, but develop a wasting syndrome.

Expression survey of genes critical for tooth development in the human embryonic tooth germ.

In the developing murine tooth, the expression patterns of numerous regulatory genes have been examined and their roles have begun to be revealed. To unveil the molecular mechanisms that regulate human tooth morphogenesis, we examined the expression patterns of several regulatory genes, including BMP4, FGF8, MSX1, PAX9, PITX2, and SHOX2, and compared them with that found in mice. All of these genes are known to play critical roles in murine tooth development.

Polycomblike-2-deficient mice exhibit normal left-right asymmetry.

Polycomb group (PcG) proteins are required for maintaining the repressed state of developmentally important genes such as homeotic genes. Polycomblike (Pcl), a member of PcG genes with two characteristic PHD finger motifs, was shown to strongly enhance the effects of PcG genes in Drosophila. Three Pcl genes exist in the mouse genome, with their function largely unknown.

[New option for gene-targeting vector construction Red/ET recombination].

The study of human new gene's function has become an increasingly active academic field basically relying on the gene knockout (KO) mouse. The construction of targeting vector economically and efficiently has turned into the key step to acquire a KO mouse because of the low efficiency of recombination with traditional constructed targeting vector. For study of the function of new gene-Resp18, we brought in a new DNA engineering platform-Red/ET recombination to construct Resp18 targeting vector.

Application of lentivirus-mediated RNAi in studying gene function in mammalian tooth development.

RNA interference (RNAi) has recently become a powerful tool to silence gene expression in mammalian cells, but its application in assessing gene function in mammalian developing organs remains highly limited. Here we describe several unique developmental properties of the mouse molar germ. Embryonic molar mesenchyme, but not the incisor mesenchyme, once dissociated into single cell suspension and re-aggregated, retains its odontogenic potential, the capability of a tissue to instruct an adjacent tissue to initiate tooth formation.

Regional regulation of palatal growth and patterning along the anterior-posterior axis in mice.

Cleft palate is a congenital disorder arising from a failure in the multistep process of palate development. In its mildest form the cleft affects only the posterior soft palate. In more severe cases the cleft includes the soft (posterior) and hard (anterior) palate.

Shox2-deficient mice exhibit a rare type of incomplete clefting of the secondary palate.

The short stature homeobox gene SHOX is associated with idiopathic short stature in humans, as seen in Turner syndrome and Leri-Weill dyschondrosteosis, while little is known about its close relative SHOX2. We report the restricted expression of Shox2 in the anterior domain of the secondary palate in mice and humans. Shox2-/- mice develop an incomplete cleft that is confined to the anterior region of the palate, an extremely rare type of clefting in humans.

Cloning of full length cDNA sequence of the mouse ameloblastin.

Objective: Screening for special genes of matrix proteins of dentin and enamel of mouse dental germ.

Methods: A cDNA library of dental germ of mouse was screened by differential display. The interesting clones were sequenced.