Nesrine Benkafadar

All Publications

• Hair cell regeneration, reinnervation, and restoration of hearing thresholds in the avian hearing organ. Cell reports Sato, M. P., Benkafadar, N., Heller, S. 2024; 43 (3): 113822

  Abstract

  Hearing starts, at the cellular level, with mechanoelectrical transduction by sensory hair cells. Sound information is then transmitted via afferent synaptic connections with auditory neurons. Frequency information is encoded by the location of hair cells along the cochlear duct. Loss of hair cells, synapses, or auditory neurons leads to permanent hearing loss in mammals. Birds, in contrast, regenerate auditory hair cells and functionally recover from hearing loss. Here, we characterized regeneration and reinnervation in sisomicin-deafened chickens and found that afferent neurons contact regenerated hair cells at the tips of basal projections. In contrast to development, synaptic specializations are established at these locations distant from the hair cells' bodies. The protrusions then contracted as regenerated hair cells matured and became functional 2 weeks post-deafening. We found that auditory thresholds recovered after 4-5 weeks. We interpret the regeneration-specific synaptic reestablishment as a location-preserving process that might be needed to maintain tonotopic fidelity.

  View details for DOI 10.1016/j.celrep.2024.113822

  View details for PubMedID 38393948

• Hair cell regeneration, reinnervation, and restoration of hearing thresholds in the avian hearing organ Cell Reports Sato, M. P., Benkafadar, N., Heller, S. 2024; 43

  View details for DOI 10.1016/j.celrep.2024.113822

• An essential signaling cascade for avian auditory hair cell regeneration. Developmental cell Benkafadar, N., Sato, M. P., Ling, A. H., Janesick, A., Scheibinger, M., Jan, T. A., Heller, S. 2023

  Abstract

  Hearing loss is a chronic disease affecting millions of people worldwide, yet no restorative treatment options are available. Although non-mammalian species can regenerate their auditory sensory hair cells, mammals cannot. Birds retain facultative stem cells known as supporting cells that engage in proliferative regeneration when surrounding hair cells die. Here, we investigated gene expression changes in chicken supporting cells during auditory hair cell death. This identified a pathway involving the receptor F2RL1, HBEGF, EGFR, and ERK signaling. We propose a cascade starting with the proteolytic activation of F2RL1, followed by matrix-metalloprotease-mediated HBEGF shedding, and culminating in EGFR-mediated ERK signaling. Each component of this cascade is essential for supporting cell S-phase entry in vivo and is integral for hair cell regeneration. Furthermore, STAT3-phosphorylation converges with this signaling toward upregulation of transcription factors ATF3, FOSL2, and CREM. Our findings could provide a basis for designing treatments for hearing and balance disorders.

  View details for DOI 10.1016/j.devcel.2023.11.028

  View details for PubMedID 38128539

• Topical Delivery of Elastic Liposomal Vesicles for Treatment of Middle and Inner Ear Diseases. ACS applied bio materials Kashfi Sadabad, R., Xia, A., Benkafadar, N., Faniku, C., Preciado, D., Yang, S., Valdez, T. A. 2022

  Abstract

  We present a topical drug delivery mechanism through the ear canal to the middle and inner ear using liposomal nanoparticles without disrupting the integrity of the tympanic membrane. The current delivery method provides a noninvasive and safer alternative to transtympanic membrane injections, ear tubes followed by ear drops administration, and systemic drug formulations. We investigate the capability of liposomal NPs, particularly transfersomes (TLipo), used as drug delivery vesicles to penetrate the tympanic membrane (TM) and round window membrane (RWM) with high affinity, specificity, and retention time. The TLipo is applied to the ear canal and found to pass through the tympanic membrane quickly in 3 h post drug administration. They are identified in the middle ear cavity 6 h and in the inner ear 24 h after drug administration. We performed cytotoxicity in vitro and ototoxicity in vivo studies. Cell viability shows no significant difference between the applied TLipo concentration and control. Furthermore, auditory brainstem response (ABR) reveals no hearing loss in 1 week and 1 month post-administration. Immunohistochemistry results demonstrate no evidence of hair cell loss in the cochlea at 1 month following TLipo administration. Together, the data suggested that TLipo can be used as a vehicle for topical drug delivery to the middle ear and inner ear.

  View details for DOI 10.1021/acsabm.2c00569

  View details for PubMedID 36179346

• Cell-type identity of the avian utricle. Cell reports Scheibinger, M., Janesick, A., Benkafadar, N., Ellwanger, D. C., Jan, T. A., Heller, S. 2022; 40 (13): 111432

  Abstract

  The avian utricle, a vestibular organ of the inner ear, displays turnover of sensory hair cells throughout life. This is in sharp contrast to the mammalian utricle, which shows limited regenerative capacity. Here, we use single-cell RNA sequencing to identify distinct marker genes for the different sensory hair cell subtypes of the chicken utricle, which we validated in situ. We provide markers for spatially distinct supporting cell populations and identify two transitional cell populations of dedifferentiating supporting cells and developing hair cells. Trajectory reconstruction resulted in an inventory of gene expression dynamics of natural hair cell generation in the avian utricle.

  View details for DOI 10.1016/j.celrep.2022.111432

  View details for PubMedID 36170825

• Avian auditory hair cell regeneration is accompanied by JAK/STAT-dependent expression of immune-related genes in supporting cells. Development (Cambridge, England) Janesick, A., Scheibinger, M., Benkafadar, N., Kirti, S., Heller, S. 2022

  Abstract

  The avian hearing organ is the basilar papilla that, in sharp contrast to the mammalian cochlea, can regenerate sensory hair cells and thereby recover from deafness within weeks. The mechanisms that trigger, sustain, and terminate the regenerative response in vivo are largely unknown. Here, we profile the changes in gene expression in the chicken basilar papilla after aminoglycoside antibiotic-induced hair cell loss using RNA-sequencing. We identified changes in gene expression of a group of immune-related genes and confirmed with single-cell RNA-sequencing that these changes occur in supporting cells. In situ hybridization was used to further validate these findings. We determined that the JAK/STAT signaling pathway is essential for upregulation of the damage-response genes in supporting cells during the second day after induction of hair cell loss. Four days after ototoxic damage, we identified newly regenerated, nascent auditory hair cells that express genes linked to termination of the JAK/STAT signaling response. The robust, transient expression of immune-related genes in supporting cells suggests a potential functional involvement of JAK/STAT signaling in sensory hair cell regeneration.

  View details for DOI 10.1242/dev.200113

  View details for PubMedID 35420675

• Cell-type identity of the avian cochlea. Cell reports Janesick, A. n., Scheibinger, M. n., Benkafadar, N. n., Kirti, S. n., Ellwanger, D. C., Heller, S. n. 2021; 34 (12): 108900

  Abstract

  In contrast to mammals, birds recover naturally from acquired hearing loss, which makes them an ideal model for inner ear regeneration research. Here, we present a validated single-cell RNA sequencing resource of the avian cochlea. We describe specific markers for three distinct types of sensory hair cells, including a previously unknown subgroup, which we call superior tall hair cells. We identify markers for the supporting cells associated with tall hair cells, which represent the facultative stem cells of the avian inner ear. Likewise, we present markers for supporting cells that are located below the short cochlear hair cells. We further infer spatial expression gradients of hair cell genes along the tonotopic axis of the cochlea. This resource advances neurobiology, comparative biology, and regenerative medicine by providing a basis for comparative studies with non-regenerating mammalian cochleae and for longitudinal studies of the regenerating avian cochlea.

  View details for DOI 10.1016/j.celrep.2021.108900

  View details for PubMedID 33761346

• Transcriptomic characterization of dying hair cells in the avian cochlea. Cell reports Benkafadar, N. n., Janesick, A. n., Scheibinger, M. n., Ling, A. H., Jan, T. A., Heller, S. n. 2021; 34 (12): 108902

  Abstract

  Sensory hair cells are prone to apoptosis caused by various drugs including aminoglycoside antibiotics. In mammals, this vulnerability results in permanent hearing loss because lost hair cells are not regenerated. Conversely, hair cells regenerate in birds, making the avian inner ear an exquisite model for studying ototoxicity and regeneration. Here, we use single-cell RNA sequencing and trajectory analysis on control and dying hair cells after aminoglycoside treatment. Interestingly, the two major subtypes of avian cochlear hair cells, tall and short hair cells, respond differently. Dying short hair cells show a noticeable transient upregulation of many more genes than tall hair cells. The most prominent gene group identified is associated with potassium ion conductances, suggesting distinct physiological differences. Moreover, the dynamic characterization of >15,000 genes expressed in tall and short avian hair cells during their apoptotic demise comprises a resource for further investigations toward mammalian hair cell protection and hair cell regeneration.

  View details for DOI 10.1016/j.celrep.2021.108902

  View details for PubMedID 33761357

• ROS-Induced Activation of DNA Damage Responses Drives Senescence-Like State in Postmitotic Cochlear Cells: Implication for Hearing Preservation. Molecular neurobiology Benkafadar, N., François, F., Affortit, C., Casas, F., Ceccato, J. C., Menardo, J., Venail, F., Malfroy-Camine, B., Puel, J. L., Wang, J. 2019

  Abstract

  In our aging society, age-related hearing loss (ARHL) has become a major socioeconomic issue. Reactive oxygen species (ROS) may be one of the main causal factors of age-related cochlear cell degeneration. We examined whether ROS-induced DNA damage response drives cochlear cell senescence and contributes to ARHL from the cellular up to the system level. Our results revealed that sublethal concentrations of hydrogen peroxide (H2O2) exposure initiated a DNA damage response illustrated by increased γH2AX and 53BP1 expression and foci formation mainly in sensory hair cells, together with increased levels of p-Chk2 and p53. Interestingly, postmitotic cochlear cells exposed to H2O2 displayed key hallmarks of senescent cells, including dramatically increased levels of p21, p38, and p-p38 expression, concomitant with decreased p19 and BubR1 expression and positive senescence-associated β-galactosidase labeling. Importantly, the synthetic superoxide dismutase/catalase mimetic EUK-207 attenuated H2O2-induced DNA damage and senescence phenotypes in cochlear cells in vitro. Furthermore, systemic administration of EUK-207 reduced age-related loss of hearing and hair cell degeneration in senescence-accelerated mouse-prone 8 (SAMP8) mice. Altogether, these findings highlight that ROS-induced DNA damage responses drive cochlear cell senescence and contribute to accelerated ARHL. EUK-207 and likely other antioxidants with similar mechanisms of action could potentially postpone cochlear aging and prevent ARHL in humans.

  View details for DOI 10.1007/s12035-019-1493-6

  View details for PubMedID 30693443

• New Strategies for Improving the Quality of Life of Cancer Survivors: Reversible p53 Inhibition Journal of Cancer Science & Therapy Benkafadar, N., Coyat, C., Lloyd, R., Puel , J., Wang, J. 2017; 9(6): 490-491
• Reversible p53 inhibition prevents cisplatin ototoxicity without blocking chemotherapeutic efficacy. EMBO molecular medicine Benkafadar, N., Menardo, J., Bourien, J., Nouvian, R., François, F., Decaudin, D., Maiorano, D., Puel, J., Wang, J. 2017; 9 (1): 7-26

  Abstract

  Cisplatin is a widely used chemotherapy drug, despite its significant ototoxic side effects. To date, the mechanism of cisplatin-induced ototoxicity remains unclear, and hearing preservation during cisplatin-based chemotherapy in patients is lacking. We found activation of the ATM-Chk2-p53 pathway to be a major determinant of cisplatin ototoxicity. However, prevention of cisplatin-induced ototoxicity is hampered by opposite effects of ATM activation upon sensory hair cells: promoting both outer hair cell death and inner hair cell survival. Encouragingly, however, genetic or pharmacological ablation of p53 substantially attenuated cochlear cell apoptosis, thus preserving hearing. Importantly, systemic administration of a p53 inhibitor in mice bearing patient-derived triple-negative breast cancer protected auditory function, without compromising the anti-tumor efficacy of cisplatin. Altogether, these findings highlight a novel and effective strategy for hearing protection in cisplatin-based chemotherapy.

  View details for DOI 10.15252/emmm.201606230

  View details for PubMedID 27794029

  View details for PubMedCentralID PMC5210089

• Impairment of Visual Function and Retinal ER Stress Activation in Wfs1-Deficient Mice PLOS ONE Bonnet Wersinger, D., Benkafadar, N., Jagodzinska, J., Hamel, C., Tanizawa, Y., Lenaers, G., Delettre, C. 2014; 9 (5)

  View details for DOI 10.1371/journal.pone.0097222