Lang Lab

Leadership

Hainan Lang, M.D., Ph.D.

Professor
Department of Pathology & Laboratory Medicine
Office: Room 401 Walton Research Building
Email: langh@musc.edu
Phone: 843-792-8483

Figures for Cellular and Molecular Mechanisms of Sensorineural Hearing Loss

Research Interests

Cellular and Molecular Mechanisms of Sensorineural Hearing Loss

Genetically modified mouse models and human inner ear tissues have been used for understanding the cellular and molecular mechanisms of auditory nerve survival and degeneration in several pathological conditions, including aging, exposure to noise and ototoxic drugs and genetic defects. We focus on the functional roles of glial cell dysfunction, neural crest cell associated transcription factors, RNA binding proteins, complement system, and their related regulatory networks for enhancing remyelination, preventing or protecting the auditory nerve from degeneration and promoting auditory nerve survival and functional recovery after cochlear injury. This translational research program provides an outstanding training opportunity for (1) cutting-edge cellular and molecular procedures in hearing research such as molecular imaging of living cochlear cells, 3D cell culture assay, and RNA-seq analysis of the degenerative cochlea; (2) processing and examination of mouse and human temporal bone tissues; (3) contemporary histopathological and high-resolution imaging techniques to assay human and animal inner ear specimens; and 4) evaluation of auditory function using electrophysiological techniques including the measurements of auditory nerve compound action potentials, spontaneous activities of single auditory nerve fiber, and auditory brainstem responses. The research program has been supported by grants from NIH/NIDCD for more than 20 years.

Figure 1. Axon-glial junctions in the auditory nerve of young adult mice. A: Molecula

organization of the node of Ranvier (voltage-gated sodium channel, Nav; voltage-gated

potassium channel, Kv). The schematic was modified from Girault and Peles (2002). B-D: A
schematic (the top panel in B) shows the pathway of the spiral ganglion neuron (SGN) neurites at the habenula opening (Hab), osseous spiral lamina (OSL), Rosenthal’s canal (RC) and modiolus (Mod). Heminodes (white arrows) and nodes (white arrowheads) were stained with Cntn1 (green arrowheads) and NrCam (red) at the Hab (B,C), OSL (B,C), RC (D) and Mod (D) of adult CBA/CaJ mice. The boxed area in C shows an enlarged node image. E-F: Features of a node of Ranvier in RC of another mouse. F is the enlarged image of the boxed area in E showing the septate-like axoglial junctions (arrowheads) that connect the paranodal loops with axolemma. G: Paranodes (arrows) in the auditory nerve of a 91-year-old donor. Insert shows Cntn1 in the fiber region preceding the SGN soma (white arrowhead) and another similar fiber lacking Cntn1 reactivity (black arrowheads Figure 2. Noise exposure induced pathophysiological alterations in young adult CBA/CaJ mice. A,B: Mean auditory brainstem response (ABR) thresholds revealed a dynamic alteration of auditory function immediately (Im), and at 1, 3, 7, 14 and 30 days (D1-D30) after noise exposure. Adult CBA/CaJ mice were exposed to an octave-band noise (8-16 kHz) at 100, 106 or 112 dB SPL for two hours. C,D: There was a marked loss of ribbon synapses (stained with anti-CtBP2 antibody, green) under inner hair cells (IHCs) at frequency regions above 22.3 kHz at both D1 and D14 after 106 dB SPL noise exposure. E: ABR Wave I amplitudes were reduced at 32 kHz at D3 (red line with dots) after 106 dB noise exposure. 


Peripheral Auditory System Deficits and Autism-Like Behaviors 
This is an exciting and newly developed project, which addresses the novel hypothesis that abnormal macrophage related activities, resulting from gene deficiency, lead to hearing loss and that these changes may be associated with communication impairment in Autism Spectrum Disorder (ASD) and other neurodevelopmental disorders. For example, mutations or deletions in the MEF2C gene has recently been linked to ASD. In collaboration with Dr. Christopher Cowan from the Department of Neuroscience our experiments



Figure 3.  Expression of MEF2C in cochlear macrophages within the auditory nerve (AN) of postnatal mice. (A) Gene expression profiles of 558 macrophage/immune-related genes differentially expressed in AN between P3 and young adult CBA/CaJ mice (log FC >0.3; p-adjusted <0.05). Macrophage/immune-related genes were compiled from the Gene Ontology Database. (B) Venn diagram depicting overlap among 1) ASD-risk genes (SFARI categories 1-4; https://gene.sfari.org), 2) human orthologs of Mef2c-dependent genes identified in mouse microglia, and 3) human orthologs of macrophage/immune-related genes outlined in (A). MEF2C was one of four genes identified in each analysis. (C) Expression of Mef2c mRNA is higher in postnatal AN compared to young adult AN.  Graph depicts RNA-seq standardized counts. (D) Expression of Mef2c (green) in macrophages in mouse P7 AN.  Macrophages were identified by immunostaining for Iba1 (red).

 

Adult Stem/Progenitor Cell and Auditory Nerve Repair

Our research on isolation of adult neural stem/progenitor cells from the adult mouse auditory nerve is aimed at replacing damaged spiral ganglion neurons, preventing neuron degeneration and promoting auditory functional recovery. Several lines of studies are ongoing with a focus on remyelination and de-differentiation of adult glial cells after acute auditory nerve injury resulting from noise- or ototoxic drug-exposure. A variety of advanced methods are employed to 1) isolate and expand neural stem/progenitor cells; 2) purify and characterize neural stem/progenitor cells using transgenic mouse models and fluorescence-activated cell sorting; and 3) identify the molecular characteristics of neural stem/progenitor cells using next generation sequencing, gene expression profiling at the single cell level (e.g., single cell RNA-seq), complementary proteomics assays and super resolution imaging analysis.

Figures for Neural crest-derived stem cells (NCSCs) generated from adult mouse cochlear tissues and human CD 34+ bone marrow cells
 
Figure 4. Neural crest-derived stem cells (NCSCs) generated from adult mouse cochlear tissues and human CD 34+ bone marrow cells. A: Adult mouse cochlear tissues isolated from auditory nerve (AN) and cochlear lateral wall (LA) give rise to self-renewing spheres. A majority of cochlear sphere-derived cells express the NCSC marker nestin and cell proliferation marker BrdU. B: Cochlear NCSCs generate cells expressing the neuronal marker TuJ1 and other neural crest lineage cell markers such as Sox10 and P75 under a neural differentiation condition. C: Purified CD34+ cells from adult human bone marrow give rise to self-renewing spheres expressing NCSC markers. Human CD34+ cells were isolated from bone marrow of a 21 year-old donor.|

Selected Recent Publications

  1. Lang H, Noble KV, Barth JL, Rumschlag JA, Jenkins TR, Storm SL, Eckert MA, Dubno JR, Schulte BA (2023). The stria vascularis in mice and humans is an early site of age-related cochlear degeneration, macrophage dysfunction, and inflammation. J Neurosci 43, 5057-5075. PMCID: PMC10324995.

  2. Brown LN, Barth JL, Jafri S, Rumschlag JA, Jenkins TR, Atkinson C, Lang H (2023). Complement factor B is essential for the proper function of the peripheral auditory system. Front Neurol 14:1214408. PMCID: PMC10408708.

  3. McChesney N, Barth JL, Rumschlag JR, Tan J, Harrington AJ, Noble KV, McClaskey CM, Elvis P, Vaena SG, Romeo MJ, Harris KC, Cowan CW, Lang H (2022). Peripheral auditory nerve impairment in a mouse model of syndromic autism. J Neurosci 42, 8002-8018 (Selected for cover photo). PMCID: PMC9617620

  4. Rumschlag JA, McClaskey CM, Dias JW, Kerouac LB, Noble KV, Panganiban C, Lang H, Harris KC (2022). Age-related central gain with degraded neural synchrony in the auditory brainstem of mice and humans. Neurobiol Aging 115, 50-59. PMCID: PMC9153923

  5. Panganiban CH, Barth JL, Tan J, Noble KV, McClaskey CM, Howard BA, Jafri SH, Dias JW, Harris KC, Lang H (2021). Two distinct types of nodes of Ranvier support auditory nerve function in the mouse cochlea. Glia 70, 768-791. PMCID: PMC8994501

  6. Liu T, Li G, Noble KV, Li Yong, Barth JL, Schulte BA, Lang H (2019). Age-dependent alterations of Kir4.1 expression in neural crest-derived cells of the mouse and human cochlea. Neurobiol Aging 18, 80:210-222. PMCID: PMC6679794

  7. Noble KV, Liu T, Matthews L, Schulte BA, Lang H (2019). Age-related alterations in resident immune cells of the human cochlea. Front Neurol 10, 895. PMCID: PMC6707808

  8. Noble KV, Reyzer ML, Barth JL, McDonald H, Tuck M, Schey KL, Krug EL, Lang H (2018). Use of proteomic imaging coupled with transcriptomic analysis to identify biomolecules responsive to cochlear injury. Front Mol Neurosci 11,243. PMCID: PMC30065626

  9. Panganiban CH, Barth JL, Darbelli L, Xing Y, Zhang J, Li H, Noble KV, Liu T,Brown LN, Schulte BA, Richard S, Lang H (2018). Noise-induced dysregulation ofQuaking RNA binding proteins contributes to auditory nerve demyelination and hearing loss. J Neurosci 38, 2551-2568. PMCID: PMC5858596

  10. Brown LN, Xing Y, Noble KV, Barth JL, Panganiban CH, Smythe NM, Bridges MC, Zhu J, Lang H (2017). Macrophage-mediated glial cell elimination in the postnatal mouse cochlea. Front Mol Neurosci10, 407. PMCID: PMC5770652

  11. Lang H, Nishimoto E, Xing Y, Brown LN, Noble KV, Barth JL, LaRue AC, Ando K, Schulte BA (2016). Contributions of mouse and human hematopoietic cells to remodeling of the adult auditory nerve after neuron loss. Mol Ther 24, 2000-2011. PMCID: PMC5154482

  12. Lang H, Xing Y, Brown LN, Samuvel DJ, Panganiban CH, Havens LT, Balasubramanian S, Wegner M, Krug EL, Barth JL (2015). Neural stem/progenitor cell properties of glial cells in the adult mouse auditory nerve. Sci Rep 5, 3383. PMCID: PMC4549618

 

 

Laboratory Members
Tyreek Jenkins, Ph.D. candidate

171 Ashley Avenue, WRB
RS304 Charleston, SC 29425

Degree(s): B.S. in Biomedical Engineering, University of South Carolina Biography: Tyreek is a PhD candidate in the Molecular and Cellular Biology and Pathobiology Program at MUSC who is interested in understanding how altered mitochondrial activity in the stria vascularis, the inner ear’s cellular battery, contributes to cochlear inflammation, a hallmark characteristic of sensorineural hearing loss. As a PhD candidate in the Lang Lab, Tyreek uses advanced biochemical imaging approaches and molecular biological techniques to investigate the relationship between mitochondrial dysfunction and aberrant immune cell activity in various mouse models of hearing loss.

Shelby Ashton Payne, M.D./Ph.D. candidate


171 Ashley Avenue, WRB
RS304 Charleston, SC 29425

Biography: Shelby Payne is an MD/PhD student currently enrolled in the NIH-funded Medical Scientist Training Program (MSTP) at the MUSC. Shelby holds a Bachelor of Arts degree in Classical Studies with a minor in Speech and Hearing Sciences from Washington University in St. Louis which piqued her interest in becoming a physician-scientist and otolaryngologist. Before joining the Lang Laboratory in 2023, Shelby studied auditory neuroscience and cochlear inflammation at the Department of Otolaryngology – Head and Neck Surgery at Washington University School of Medicine (WUSM) from 2016 – 2021 where she contributed to numerous publications and presented at national conferences. She was also invited to the Biology of the Inner Ear Course at the Marine Biological Laboratory in Woods Hole, MA as a research instructor to teach students patch-clamp electrophysiology. She is interested in studying the role of the immune system in auditory pathology with the goal of pioneering novel therapeutics to treat hearing loss and diseases of the inner ear.

Emily Fabrizio-Stover, Ph.D.

71 Ashley Avenue, WRB RS610
Charleston, SC 29425

Biography: After completing my undergraduate degree at the University of Connecticut, I earned my Ph.D. at the University of Connecticut in the laboratory of Dr. Douglas Oliver. During my doctorate degree, my research focused on developing non-invasive, electrophysiological correlates of tinnitus in both laboratory animals and human subjects. As a postdoc in both the Lang lab and Harris lab, I am interested in how the excitatory/inhibitory balance in the auditory system changes with increasing age and what underlying factors contribute to this imbalance.

Jiaying Wu, B.S., M.S. Research Specialist
Juhong, Zhu, B.S., M.S. Research Specialist