Biology subjects

Houchen, C. J.

Publications and source records attributed to Houchen, C. J..

3 recordsLinked to original sources

bioRxiv2025

Wnt5a gain- and loss-of-function present distinctly in craniofacial bone

IntroductionRobinow syndrome has characteristic craniofacial and dental features and can be caused by gain- or loss-of-function variants in Wnt family member 5A (WNT5A) non-canonical signaling. The craniofacial and dental manifestation of Robinow syndrome is heterogenous, as is the effect of altered Wnt5a in animal models. The relationship between Wnt5a and craniofacial and dental phenotypes is not fully understood. MethodsTo investigate the role of Wnt5a in craniofacial and dental development, we utilized a Wnt5a conditional loss-of-function (LOF: Wnt5afl/fl;Ctskcre) and a Wnt5a conditional gain-of-function (GOF: Rosa26-LSL-Wnt5a;Ctskcre) model to determine the effect of both LOF and GOF of Wnt5a in bone cells during craniofacial and dental development. Postnatal day 10 conditional LOF Wnt5a, GOF Wnt5a, and control skulls were scanned by micro-computed tomography and assessed using traditional and geometric morphometrics. Mandibular bone apoptosis was further assessed by TUNEL staining. ResultsConditional Wnt5a LOF resulted in midface hypoplasia, increased maxillary intermolar width, increased rostral basisphenoid width, and delayed molar eruption. Wnt5a LOF mandibles did not have altered bone mineral density or bone microarchitecture unlike our previous study examining Wnt5a LOF femurs. In contrast, conditional Wnt5a GOF results in macrocephaly, shortened hard palate, increased zygomatic length, micrognathia, and mandibular process morphology changes. The micrognathia and mandibular process morphology changes in the Wnt5a GOF mice were not due to increased apoptosis. A partially penetrant snout deviation was present in both the Wnt5a LOF and GOF mice. ConclusionsCraniofacial and dental phenotype differed between mice with conditional GOF and LOF of Wnt5a, consistent with the craniofacial phenotype heterogeneity in Wnt5a-associated Robinow syndrome. We detected tooth eruption delay, mandibular condyle dysmorphology, and facial asymmetry in mice with altered Wnt5a that have not been previously reported in patients. Our data suggest precise regulation of Wnt5a is essential for proper craniofacial and dental development. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=82 SRC="FIGDIR/small/665966v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@971284org.highwire.dtl.DTLVardef@40d5f6org.highwire.dtl.DTLVardef@9f0caforg.highwire.dtl.DTLVardef@1f9ba9b_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗

bioRxiv2024

TGF-β Signaling in Cranial Neural Crest Affects Late-Stage Mandibular Bone Resorption and Length

Malocclusions are common craniofacial malformations which cause quality of life and health problems if left untreated. Unfortunately, the current treatment for severe skeletal malocclusion is invasive surgery. Developing improved therapeutic options requires a deeper understanding of the cellular mechanisms responsible for determining jaw bone length. We have recently shown that neural crest mesenchyme (NCM) can alter jaw length by controlling recruitment and function of mesoderm-derived osteoclasts. Transforming growth factor beta (TGF-{beta}) signaling is critical to craniofacial development by directing bone resorption and formation, and heterozygous mutations in TGF-{beta} type I receptor (TGFBR1) are associated with micrognathia in humans. To identify what role TGF-{beta} signaling in NCM plays in controlling osteoclasts during mandibular development, mandibles of mouse embryos deficient in the gene encoding Tgfbr1 specifically in NCM were analyzed. Our lab and others have demonstrated that Tgfbr1fl/fl;Wnt1-Cre mice display significantly shorter mandibles with no condylar, coronoid, or angular processes. We hypothesize that TGF-{beta} signaling in NCM can also direct later bone remodeling and further regulate late embryonic jaw bone length. Interestingly, analysis of mandibular bone through micro-computed tomography and Massons trichrome revealed no significant difference in bone quality between the Tgfbr1fl/fl;Wnt1-Cre mice and controls, as measured by bone perimeter/bone area, trabecular rod-like diameter, number and separation, and gene expression of Collagen type 1 alpha 1 (Col11) and Matrix metalloproteinase 13 (Mmp13). Though there was not a difference in localization of bone resorption within the mandible indicated by TRAP staining, Tgfbr1fl/fl;Wnt1-Cre mice had approximately three-fold less osteoclast number and perimeter than controls. Gene expression of receptor activator of nuclear factor kappa-{beta} (Rank) and Mmp9, markers of osteoclasts and their activity, also showed a three-fold decrease in Tgfbr1fl/fl;Wnt1-Cre mandibles. Evaluation of osteoblast-to-osteoclast signaling revealed no significant difference between Tgfbr1fl/fl;Wnt1-Cre mandibles and controls, leaving the specific mechanism unresolved. Finally, pharmacological inhibition of Tgfbr1 signaling during the initiation of bone mineralization and resorption significantly shortened jaw length in embryos. We conclude that TGF-{beta} signaling in NCM decreases mesoderm-derived osteoclast number, that TGF-{beta} signaling in NCM impacts jaw length late in development, and that this osteoblast-to-osteoclast communication may be occurring through an undescribed mechanism.

developmental biology↗

bioRxiv2023

A novel qPCR-based technique for identifying avian sex: an illustration within embryonic craniofacial bone

Sex is a biological variable important to consider in all biomedical experiments. However, analyzing sex differences in avian models can be challenging as the sexes are morphologically indistinguishable in most avian embryos. Unlike humans, female birds are the heterogametic sex with a Z and W chromosome. The female-specific W chromosome has previously been identified using species-specific polymerase chain reaction (PCR) techniques. We developed a novel quantitative real-time PCR (RT-qPCR) technique which amplifies the W chromosome gene histidine triad nucleotide binding protein W (HINTW) in chick, quail, and duck. We confirmed the accuracy of the single set of HINTW RT-qPCR primers in all three species using species-specific PCR. Bone development-related gene expression was then analyzed by sex in embryonic lower jaws of duck and quail, as duck beak size is known to be sexually dimorphic while quail beak size is not. Trends towards sexual dimorphism were found in duck gene expression but not in quail, as expected. Our novel HINTW RT-qPCR technique to identify the sex of avian embryos is a useful tool for including sex as a biological variable in analysis of a variety of tissues and cells used in developmental biology research.

developmental biology↗