Biology subjects

Oberhauser, L.

Publications and source records attributed to Oberhauser, L..

3 recordsLinked to original sources

bioRxiv2026

Deciphering auditory neuroprogenitor stemness for large-scale neuronal screening

Sensorineural hearing loss can arise from damage to sensory hair cells, auditory neurons or their synaptic connections, with auditory neuropathy and cochlear synaptopathy highlighting the importance of neural integrity for hearing. The mammalian cochlea has limited capacity to regenerate lost auditory neurons. Understanding the molecular programs that sustain cochlear progenitor expansion and neurogenic competence could support neuronal regeneration and provide renewable models for auditory drug discovery. We previously established that WNT activation combined with dual SMAD inhibition (CHIR-DS) supports scalable expansion and neuronal differentiation of mouse auditory neuroprogenitors (ANPGs). Here, we characterize the transcriptional, chromatin and metabolic changes associated with the induced state. RNA-seq and ATAC-seq identified reduced Id1 and Id2 expression and increased accessibility at proneural basic helix-loop-helix motifs, alongside transcriptional enrichment of translation, mTOR and glucose-metabolism programs. Compared with growth-factor controls, CHIR-DS-treated ANPGs showed slight increase in glycolysis at early passage. However, after long-term expansion, both glycolysis and mitochondrial respiration were markedly enhanced. Human fetal ANPGs also responded to CHIR-DS with increased sphere growth and retained neural differentiation capacity, providing proof of concept beyond the mouse system. Finally, neurons derived from stemness-induced ANPGs (siANs) supported a 384-well reporter assay and a 2,560-compound pilot screen that nominated candidate neurite-outgrowth enhancers. Together, these findings validate the pathway basis of ANPG stemness induction, characterize the resulting molecular and metabolic state, and demonstrate human feasibility and a neuronal screening application.

neuroscience↗

bioRxiv2025

Introducing a translationally relevant mouse model of radiosurgery-induced unilateral hearing loss

BackgroundStereotactic radiosurgery (SRS) is widely used to treat vestibular schwannomas but may cause irreversible hearing loss due to cochlear toxicity. The underlying mechanisms are not fully understood, and no effective otoprotective therapies exist. We aimed to establish a mouse model that replicates the clinical pattern of radiation-induced hearing loss. MethodsC57BL/6J mice (n=31) received 8 Gy (n=3), 16 Gy (n=5), 24 Gy (n=8), or 32 Gy (n=15) using the Leksell Gamma Knife ICON system. Targeting was based on the built-in cone-beam CT, co-registered with MRI and CT-based mouse atlases, to guide unilateral cochlea targeting. A single isocenter was placed lateral to the right cochlea, with the 80% isodose line traversing its medial edge. Auditory brainstem response (ABR) was measured at baseline and at 1 and 4 weeks post-SRS. A 32 Gy subgroup (n=7) was evaluated at 16 weeks. Histological analysis of cochleae was performed at 4 weeks in all groups and at 16 weeks in the long-term 32 Gy group. ResultsSRS was well tolerated, and the contralateral cochlea received a very low radiation dose. No ABR shifts were observed at 8 or 16 Gy, with only minimal histological changes. At 32 Gy, ABR threshold shifts at 22.6 and 32 kHz were evident by week 1 and worsened by week 4. Similar but milder effects occurred at 24 Gy. In the 32 Gy long-term subgroup, hearing loss progressed across all frequencies, most severely at high frequencies, alongside a sustained wave I amplitude decline. At 32 Gy, outer hair cells were reduced by 14% and 44% at 32 and 45.2 kHz, respectively, at 4 weeks, and by 38% and 80% at 16 weeks. Ribbon synapses were mildly reduced at 4 weeks and more markedly at 16 weeks in corresponding high-frequency regions. Spiral ganglion neuron density was mildly reduced at the basal and middle turns. All reported changes were statistically significant when compared to the contralateral ear. ConclusionsThis new model reproduces key features of SRS-induced cochlear toxicity, including unilateral, dose-dependent, and progressive hearing loss. It thus provides a valuable platform for investigating mechanisms and testing otoprotective strategies.

neuroscience↗

bioRxiv2022

Subcellular location defines GPCR signal transduction

G protein-coupled receptors in intracellular organelles can be activated in response to membrane permeant ligands, which contributes to the diversity and specificity of agonist action. The opioid receptors (ORs) provide a striking example, where opioid drugs activate ORs in the Golgi apparatus within seconds of drug addition. Till date, our knowledge on the signaling of intracellular GPCRs remains incomplete and it is unknown if the downstream effects triggered by ORs in plasma membrane and Golgi apparatus differ. To address this gap, we first assess the recruitment of signal transducers to ORs in both compartments. We find that Golgi-localized ORs couple to Gi/o probes and are phosphorylated by GPCR kinases (GRK2/3), but unlike plasma membrane receptors, do not recruit {beta}-arrestin or a specific G probe. Subsequent molecular dynamics simulations with OR-transducer complexes in model bilayers mimicking plasma membrane or Golgi composition reveal that the lipid environment promotes location selective coupling. Unbiased global analyses then show that OR activation in the plasma membrane and Golgi apparatus has strikingly different downstream effects on transcription and protein phosphorylation. Taken together, the study delineates OR signal transduction with unprecedented spatial resolution and reveals that the subcellular location defines the signaling effect of opioid drugs.

cell biology↗