Biology subjects

Bumann, E. E.

Publications and source records attributed to Bumann, E. E..

6 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↗

bioRxiv2022

Controlled Hydrogen Sulfide Delivery to Enhance Cell Survival in Bone Tissue Engineering

The increased local concentration of calcium ions (Ca2+) and phosphate (Pi), a natural body process for bone healing and remodeling, as well as local delivery of these ions as signaling molecules by synthetic bone graft substitutes, may lead to cytotoxic ion levels that can result in Ca2+/ Pi mitochondria overload, oxidative stress, and cell death. In this research, the effect of H2S as a cytoprotective signaling molecule to increase the tolerance of mesenchymal stem cells (MSCs) in the presence of cytotoxic level of Ca2+/Pi was evaluated. Different concentrations of sodium hydrogen sulfide (NaSH), a fast-releasing H2S donor, were exposed to cells in order to evaluate the influence of H2S on MSC proliferation. The results suggested that a range of NaSH (i.e., 0.25 - 4 mM NaSH) was non-cytotoxic and could improve cell proliferation and differentiation in the presence of cytotoxic levels of Ca2+ (32 mM) and/or Pi (16 mM). To controllably deliver H2S over time, a novel donor molecule in thioglutamic acid (GluSH) was synthesized and evaluated for its H2S release profile. Excitingly, GluSH successfully maintained cytoprotective level of H2S over 7 days. Furthermore, MSCs exposed to cytotoxic Ca2+/Pi concentrations in the presence of GluSH were able to thrive and differentiate into osteoblasts. These findings suggest that the incorporation of a sustained H2S donor such as GluSH into CaP-based bone substitutes can facilitate considerable cytoprotection making it an attractive option for complex bone regenerative engineering applications.

bioengineering↗

bioRxiv2021

Early life stress is associated with earlier emergence of permanent molars

Exposure to adversity can accelerate biological aging. However, existing biomarkers of early aging are either difficult to detect in individuals at scale, like epigenetic signatures, or cannot be detected until late childhood, like pubertal onset. We evaluated the hypothesis that early adversity is associated with earlier molar eruption, an easily assessed measure that has been used to track the length of childhood across primates. In a pre-registered analysis (N = 117, ages 4-7), we demonstrate that lower family income and exposure to adverse childhood experiences (ACEs) are significantly associated with earlier eruption of the first permanent molars, as rated in T2-weighted magnetic resonance images (MRI). We replicate relationships between income and molar eruption in a population-representative dataset (NHANES; N = 1,973). These findings suggest that the impact of stress on the pace of biological development is evident in early childhood, and detectable in the timing of molar eruption.

neuroscience↗

bioRxiv2020

Thm2 interacts with paralog, Thm1, and sensitizes to Hedgehog signaling in postnatal skeletogenesis

Ciliopathies are genetic syndromes that link osteochondrodysplasias to dysfunction of primary cilia. Primary cilia extend from the surface of bone and cartilage cells, to receive extracellular cues and mediate signaling pathways. Mutations in several genes that encode components of the intraflagellar transport-A ciliary protein complex have been identified in skeletal ciliopathies, including THM1. Here, we report a role for genetic interaction between Thm1 and its paralog, Thm2, in skeletogenesis. THM2 localizes to the ciliary axoneme, but unlike its paralog, Thm2 deficiency does not affect ciliogenesis and Thm2-null mice survive into adulthood. Since paralogs often have redundant functions, we crossed a Thm1 null (aln) allele into the Thm2 colony. After 5 generations of backcrossing the colony onto a C57BL6/J background, we observed that by postnatal day 14, Thm2-/-; Thm1aln/+ mice are smaller than control littermates. Thm2-/-; Thm1aln/+ mice exhibit shortened long bones, narrow ribcage, shortened cranium and mandibular defects. Mutant mice also show aberrant architecture of the tibial growth plate, with an expanded proliferation zone and diminished hypertrophic zone, indicating impaired chondrocyte differentiation. Using microcomputed tomography, Thm2-/-; Thm1aln/+ tibia were revealed to have reduced cortical and trabecular bone mineral density. Deletion of one allele of Gli2, a major transcriptional activator of the Hedgehog (Hh) pathway, exacerbated the small phenotype of Thm2-/-; Thm1aln/+ mice and caused small stature in Thm2-null mice. Together, these data reveal Thm2 as a novel locus that sensitizes to Hh signaling in skeletal development. Further, Thm2-/-; Thm1aln/+ mice present a new postnatal ciliopathy model of osteochondrodysplasia.

developmental biology↗