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van der Valk, W. H.

Publications and source records attributed to van der Valk, W. H..

3 recordsLinked to original sources

Patient-Derived Inner Ear Organoids as a Disease Modeling and Therapy Validation Platform For Hereditary Inner Ear Disorders

BackgroundHereditary inner ear disorders comprise a highly heterogenous group of disorders and are a major cause of hearing and vestibular dysfunction. Despite advances in genetic diagnosis, the development of precision therapies has been limited by the lack of relevant and scalable human model systems that can accommodate the wide spectrum of disease-causing variants and support the evaluation of therapeutic interventions. We established patient-derived inner ear organoids (IEOs) as a platform to assess antisense oligonucleotide (ASO)-based therapeutic strategies for hereditary hearing loss. MethodsTwo representative genetic models were selected: recessive syndromic Usher syndrome type IIa (USH2A) and dominant non-syndromic DFNA9 (COCH). Human induced pluripotent stem cells (iPSCs) were generated from a patient carrying a homozygous pathogenic USH2A variant and a patient carrying a frequently occurring pathogenic COCH variant. In parallel, isogenic iPSC lines were created by introducing the same disease-causing variants into a healthy donor background. Following differentiation into IEOs, disease-associated transcript expression was evaluated. Splice-switching and RNase H1-mediated gapmer ASOs were assessed for target engagement. ASO biodistribution and cellular uptake was also examined in both IEOs and adult human vestibular tissue. ResultsPatient-derived and isogenic iPSCs were successfully differentiated into IEOs that recapitulated disease-associated transcript expression. ASOs showed efficient uptake into disease-relevant cell populations in both IEOs and adult human vestibular tissue. In USH2A-variant IEOs, splice-switching ASO treatment corrected aberrant splicing. In COCH-variant IEOs, gapmer ASO treatment reduced total COCH transcript levels, achieving up to 75% knockdown in patient-derived IEOs. ConclusionsPatient-derived and isogenic variant IEOs provide a versatile and scalable human platform for evaluating ASO therapies for hereditary hearing loss. Their adaptability to diverse genetic variants, inheritance patterns, and ASO modalities makes them well suited to address the genetic heterogeneity of hereditary inner ear diseases and establishes IEOs as a broadly applicable preclinical model for rare hereditary inner ear diseases.

neuroscience↗

Human pluripotent stem cells-derived Inner ear organoids recapitulate otic development in vitro.

Our molecular understanding of the early stages of human inner ear development has been limited by the difficulty in accessing fetal samples at early gestational stages. As an alternative, previous studies have shown that inner ear morphogenesis can be partially recapitulated using induced pluripotent stem cells (iPSCs) directed to differentiate into Inner Ear Organoids (IEOs). Once validated and benchmarked, these systems could represent unique tools to complement and refine our understanding of human otic differentiation and model developmental defects. Here, we provide the first direct comparisons of the early human embryonic otocyst and human iPSC-derived IEOs. We use multiplexed immunostaining, and single-cell RNA sequencing to characterize IEOs at three key developmental steps, providing a new and unique signature of in vitro derived otic -placode, -epithelium, -neuroblasts, and -sensory epithelia. In parallel, we evaluate the expression and localization of critical markers at these equivalent stages in human embryos. We show that the placode derived in vitro (days 8-12) has similar marker expression to the developing otic placode of Carnegie Stage (CS) 11 embryos and subsequently (days 20-40) this gives rise to otic epithelia and neuroblasts comparable to the CS13 embryonic stage. Differentiation of sensory epithelia, including supporting cells and hair cells starts in vitro at days 50-60 of culture. The maturity of these cells is equivalent to vestibular sensory epithelia at week 10 or cochlear tissue at week 12 of development, before functional onset. Together, our data indicate that the current state-of-the-art protocol enables the specification of bona fide otic tissue, supporting the further application of IEOs to inform inner ear biology and disease.

developmental biology↗

A Single-Cell Level Comparison of Human Inner Ear Organoids and the Human Cochlea and Vestibular Organs

Genetic inner ear disorders are among the most common congenital abnormalities and lead to hearing loss and balance disorders. Ideally, tissue culture models of the inner ear should contain a functional unit combining otic sensory and nonsensory cell types to recapitulate the varied etiologies of inner ear disorders. Here, we evaluated cell type diversity of late-stage human pluripotent stem cell-derived inner ear organoids using single-cell transcriptomic analysis, electron microscopy and immunohistochemistry. We observed the induction of on-target inner ear-related periotic mesenchymal cells alongside off-target induction of skeletal myocytes, endothelial cells, and ependymal cells. By constructing a single-cell transcriptomic atlas of the human fetal and adult inner ear, we show that epithelium in the inner ear organoids contains cochlear and vestibular identities similar to the developing human inner ear. Moreover, the inner ear organoids contain immature type I and type II vestibular hair cells. Within these putative inner ear cell types, we confirmed the expression of genes and proteins linked to sensorineural hearing loss. This approach using human inner ear organoids would allow for disease modeling of specific genetic inner ear pathologies in the sensory and nonsensory domains of the inner ear.

developmental biology↗