Faculty Bibliography

BACKGROUND:Developing genomic resources for a diverse range of species is an important step towards understanding the mechanisms underlying complex traits. Specifically, organisms that exhibit unique and accessible phenotypes-of-interest allow researchers to address questions that may be ill-suited to traditional model organisms. We sequenced the genome and transcriptome of Alston's singing mouse (Scotinomys teguina), an emerging model for social cognition and vocal communication. In addition to producing advertisement songs used for mate attraction and male-male competition, these rodents are diurnal, live at high-altitudes, and are obligate insectivores, providing opportunities to explore diverse physiological, ecological, and evolutionary questions. RESULTS:Using PromethION, Illumina, and PacBio sequencing, we produced an annotated genome and transcriptome, which were validated using gene expression and functional enrichment analyses. To assess the usefulness of our assemblies, we performed single nuclei sequencing on cells of the orofacial motor cortex, a brain region implicated in song coordination, identifying 12 cell types. CONCLUSIONS:These resources will provide the opportunity to identify the molecular basis of complex traits in singing mice as well as to contribute data that can be used for large-scale comparative analyses.

Locomotion requires precise control of the strength and speed of muscle contraction and is achieved by recruiting functionally distinct subtypes of motor neurons (MNs). MNs are essential to movement and differentially susceptible in disease, but little is known about how MNs acquire functional subtype-specific features during development. Using single-cell RNA profiling in embryonic and larval zebrafish, we identify novel and conserved molecular signatures for MN functional subtypes and identify genes expressed in both early post-mitotic and mature MNs. Assessing MN development in genetic mutants, we define a molecular program essential for MN functional subtype specification. Two evolutionarily conserved transcription factors, Prdm16 and Mecom, are both functional subtype-specific determinants integral for fast MN development. Loss of prdm16 or mecom causes fast MNs to develop transcriptional profiles and innervation similar to slow MNs. These results reveal the molecular diversity of vertebrate axial MNs and demonstrate that functional subtypes are specified through intrinsic transcriptional codes.

Social learning (SL) through experience with conspecifics can facilitate the acquisition of many behaviors. Thus, when Mongolian gerbils are exposed to a demonstrator performing an auditory discrimination task, their subsequent task acquisition is facilitated, even in the absence of visual cues. Here, we show that transient inactivation of auditory cortex (AC) during exposure caused a significant delay in task acquisition during the subsequent practice phase, suggesting that AC activity is necessary for SL. Moreover, social exposure induced an improvement in AC neuron sensitivity to auditory task cues. The magnitude of neural change during exposure correlated with task acquisition during practice. In contrast, exposure to only auditory task cues led to poorer neurometric and behavioral outcomes. Finally, social information during exposure was encoded in the AC of observer animals. Together, our results suggest that auditory SL is supported by AC neuron plasticity occurring during social exposure and prior to behavioral performance.

OBJECTIVES/HYPOTHESIS/OBJECTIVE:Glucocorticoids (GC)s are commonly employed to treat vocal fold (VF) pathologies. However, VF atrophy has been associated with intracordal GC injections. Dexamethasone-induced skeletal muscle atrophy is well-documented in other tissues and believed to be mediated by increased muscle proteolysis via upregulation of Muscle Ring Finger (MuRF)-1 and Atrogin-1. Mechanisms of dexamethasone-mediated VF atrophy have not been described. This pilot study employed in vitro and in vivo models to investigate the effects of dexamethasone on VF epithelium, thyroarytenoid (TA) muscle, and TA-derived myoblasts. We hypothesized that dexamethasone will increase atrophy-associated gene expression in TA muscle and myoblasts and decrease TA muscle fiber size and epithelial thickness. STUDY DESIGN/METHODS:In vitro, pre-clinical. METHODS:TA myoblasts were isolated from a female Sprague-Dawley rat and treated with 1 μM dexamethasone for 24-h. In vivo, 15 New Zealand white rabbits were randomly assigned to three treatment groups: (1) bilateral intracordal injection of 40 μL dexamethasone (10 mg/ml; n = 5), (2) volume-matched saline (n = 5), and (3) untreated controls (n = 5). Larynges were harvested 7-days post-injection. Across in vivo and in vitro experimentation, MuRF-1 and Atrogin-1 mRNA expression were measured via RT-qPCR. TA muscle fiber cross-sectional area (CSA) and epithelial thickness were also quantified in vivo. RESULTS:Dexamethasone increased MuRF-1 gene expression in TA myoblasts. Dexamethasone injection, however, did not alter atrophy-associated gene expression, TA CSA, or epithelial thickness in vivo. CONCLUSION/CONCLUSIONS:Dexamethasone increased atrogene expression in TA myoblasts, providing foundational insight into GC induced atrophic gene transcription. Repeated dexamethasone injections may be required to elicit atrophy in vivo. LEVEL OF EVIDENCE/METHODS:N/A Laryngoscope, 2022.

OBJECTIVES:Immune-checkpoint inhibitors (ICI) are being utilized with increasing frequency and may be linked to neurologic and audiovestibular toxicities. This report aimed to describe a case of ICI-induced sensorineural hearing loss ultimately requiring bilateral cochlear implantation. METHODS:A 42-year-old female with stage IV metastatic melanoma of the perianal skin was treated with ipilimumab (blocker of cytotoxic T-lymphocyte associated protein 4 [CTLA-4]) and nivolumab (anti-programmed cell death protein 1 [PD1]). After 21 weeks of therapy, she developed sudden vertigo and bilateral hearing loss. A full workup including MRI and lumbar puncture ruled out intracranial parenchymal metastases, leptomeningeal metastases, stroke and intracranial infection. ICI-associated aseptic meningoencephalitis was therefore diagnosed. The patient received systemic steroids as well as intratympanic steroids, which temporarily improved hearing, but eventually developed permanent, bilateral profound sensorineural hearing loss. RESULTS:The patient received bilateral cochlear implants and has demonstrated good performance one year after implantation. DISCUSSION:ICI are being increasingly used to treat a variety of advanced malignancies. This is the first report of bilateral cochlear implants in the context of profound hearing loss after an immunotherapy induced meningoencephalitis. CONCLUSION:ICI carries the risk of potential ototoxicity, including profound SNHL as depicted in our case. Cochlear implantation proved to be beneficial and may be considered in patients with ICI-related hearing loss.

Oxytocin is a neuropeptide that is important for maternal physiology and childcare, including parturition and milk ejection during nursing^1-6. Suckling triggers the release of oxytocin, but other sensory cues-specifically, infant cries-can increase the levels of oxytocin in new human mothers⁷, which indicates that cries can activate hypothalamic oxytocin neurons. Here we describe a neural circuit that routes auditory information about infant vocalizations to mouse oxytocin neurons. We performed in vivo electrophysiological recordings and photometry from identified oxytocin neurons in awake maternal mice that were presented with pup calls. We found that oxytocin neurons responded to pup vocalizations, but not to pure tones, through input from the posterior intralaminar thalamus, and that repetitive thalamic stimulation induced lasting disinhibition of oxytocin neurons. This circuit gates central oxytocin release and maternal behaviour in response to calls, providing a mechanism for the integration of sensory cues from the offspring in maternal endocrine networks to ensure modulation of brain state for efficient parenting.

Office-based procedures can be a fulfilling part of the facial plastic practice with the right tools, personnel, and preparation. Equipping the clinic for office-based procedures has several unique considerations that ultimately impact its success. It is important to strategize preemptively regarding what treatments will be offered and the respective equipment that will allow the safe, cost-effective, and high-quality delivery of those treatments. Most procedures in the office-based setting are cosmetic in nature and there are often overlapping treatment modalities that target similar outcomes. Patient selection and counseling is a crucial step in preparing for office-based procedures in the effort to maximize patient satisfaction. Nearly all the most common facial plastic procedures can be delivered in the office-based based setting under local anesthesia and moderate sedation, depending on the expertise of the surgeon. To enable these and other categories of treatments, there are certain expensive pieces of technology that one might consider for their office-based practice and other fundamental supplies that are necessary for almost all practices. Though the initial investment in equipment can be costly, this article also discusses more affordable alternatives or third-party sales of devices and equipment. The field of facial plastic surgery is very dynamic and having both peer and mentorship networks is invaluable in navigating some of the financial decisions discussed herein. This article also briefly covers personnel, training, and accreditation considerations.

OBJECTIVES/OBJECTIVE:Effective treatments for vocal fold fibrosis remain elusive. Tamoxifen (TAM) is a selective estrogen receptor modulator and was recently reported to have antifibrotic actions. We hypothesized that TAM inhibits vocal fold fibrosis via altered transforming growth factor beta 1 (TGF-β1) signaling. Both in vitro and in vivo approaches were employed to address this hypothesis. METHODS: M) ± TGF-β1 (10 ng/ml) to quantify cell proliferation. The effects of TAM on genes related to fibrosis were quantified via quantitative real-time polymerase chain reaction. In vivo, rat vocal folds were unilaterally injured, and TAM was administered by oral gavage from pre-injury day 5 to post-injury day 7. The rats were randomized into two groups: 0 mg/kg/day (sham) and 50 mg/kg/day (TAM). Histological changes were examined on day 56 to assess tissue architecture. RESULTS: M) + TGF-β1, however, significantly increased Smad7 and Has3 expression and decreased Col1a1 and Acta2 expression compared to TGF-β1 alone. In vivo, TAM significantly increased lamina propria area, hyaluronic acid concentration, and reduced collagen deposition compared to sham treatment. CONCLUSIONS:TAM has antifibrotic potential via the regulation of TGF-β1/Smad signaling in vocal fold injury. These findings provide foundational data to develop innovative therapeutic options for vocal fold fibrosis. LEVEL OF EVIDENCE/METHODS:NA Laryngoscope, 2022.

BACKGROUND AND PURPOSE:Most multinodular and vacuolating neuronal tumors (MVNTs) are diagnosed and followed radiologically without any change across time. There are no surveillance guidelines or quantitative volumetric assessments of these tumors. We evaluated MVNT volumes during long follow-up periods using segmentation tools with the aim of quantitative assessment. MATERIALS AND METHODS:All patients with MVNTs in a brain MR imaging report in our system were reviewed. Patients with only 1 brain MR imaging or in whom MVNT was not clearly the most likely diagnosis were excluded. All MVNTs were manually segmented. For all follow-up examinations, absolute and percentage volume change from immediately prior and initial examinations were calculated. RESULTS:= .67), respectively. CONCLUSIONS:MVNT segmentation across follow-up brain MR imaging examinations did not demonstrate significant volume differences, suggesting that these tumors do not enlarge with time. Hence, frequent surveillance imaging of newly diagnosed MVNTs may not be necessary.

OBJECTIVE:To assess the validity of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) for evaluating thyroid nodules in children. METHODS:Patients aged <19 years with thyroid nodule(s) evaluated by ultrasound (US) from 2007-2018 at a tertiary children's hospital were included. Two radiologists scored de-identified thyroid US images using ACR TI-RADS (from 1, "benign" to 5, "highly suspicious"). The radiologists recorded size and rated vascularity for each nodule. Ultrasound findings were compared to pathology results (operative cases, n = 91) and clinical follow-up without disease progression (non-operative cases, n = 15). RESULTS:Thyroid images from 115 patients were reviewed. Nine patients were excluded due to the absence of an evaluable nodule. Forty-seven benign and 59 malignant nodules were included. Median age at ultrasound was 15 years (range 0.9-18 years). Twenty (18.9%) patients were male. There was moderate agreement between TI-RADS levels assigned by the two raters (kappa = 0.57, p < 0.001). When the raters' levels were averaged, >3 as the threshold for malignancy correctly categorized the greatest percentage of nodules (68.9%). Eleven (18.6%) malignant nodules received a TI-RADS level of 2 (n = 3) or 3 (n = 8). Sensitivity, specificity, and positive and negative predictive values were 81.4%, 53.2%, 68.6%, and 69.4%, respectively. Although not part of TI-RADS, vascularity was similar between benign and malignant nodules (p = 0.56). CONCLUSION/CONCLUSIONS:In a pediatric population, TI-RADS can help distinguish between benign and malignant nodules with comparable sensitivity and specificity to adults. However, the positive and negative predictive values suggest TI-RADS alone cannot eliminate the need for FNA. LEVEL OF EVIDENCE/METHODS:3 Laryngoscope, 2022.