Usher syndrome (USH) is the most common form of hereditary deaf-blindness in humans. USH is a complex genetic disorder, assigned to three clinical subtypes differing in onset, course, and severity, with USH1 being the most severe. Rodent USH1 models do not reflect the ocular phenotype observed in human patients to date; hence, little is known about the pathophysiology of USH1 in the human eye. One of the USH1 genes, USH1C, exhibits extensive alternative splicing and encodes numerous harmonin protein isoforms that function as scaffolds for organizing the USH interactome. RNA-seq analysis of human retinae uncovered harmonin_a1 as the most abundant transcript of USH1C. Bulk RNA-seq analysis and immunoblotting showed abundant expression of harmonin in Müller glia cells (MGCs) and retinal neurons. Furthermore, harmonin was localized in the terminal endfeet and apical microvilli of MGCs, presynaptic region (pedicle) of cones, and outer segments of rods as well as at adhesive junctions between MGCs and photoreceptor cells (PRCs) in the outer limiting membrane (OLM). Our data provide evidence for interaction of harmonin with OLM molecules in PRCs and MGCs and with rhodopsin in PRCs. Subcellular expression and colocalization of harmonin correlate with the clinical phenotype observed in USH1C patients. We also demonstrate that primary cilia defects in USH1C patient-derived fibroblasts could be reverted by the delivery of harmonin_a1 transcript isoform. Our studies thus provide novel insights into PRC cell biology, USH1C pathophysiology, and development of gene therapy treatment(s).

Human Usher syndrome (USH) is a complex genetic disorder that comprises three clinical subtypes USH1, USH2, and USH3, and the most common form of hereditary combined deaf-blindness. Since rodent USH1 models do not reflect the ocular phenotype observed in human patients to date only little is known about the pathophysiology of USH1 in the human eye. The USH1C gene is heavily alternatively spliced and encodes for numerous harmonin isoforms that function as scaffold proteins and organizer of the USH interactome. RNA-seq analysis of USH1C revealed harmonin a1 as the most abundant transcript of USH1C in the human retina. Bulk mRNA-seq and Western blots confirmed abundant expression of harmonin in Muller glia cells (MGCs) and retinal neurons. We located harmonin in the terminal endfeet and apical microvilli of MGCs and in photoreceptor cells (PRCs), particularly in cone synapses and outer segments of rods as well as at adhesive junctions between both, MGCs and PRCs in the outer limiting membrane (OLM). We evidenced the interaction of harmonin with OLM molecules and rhodopsin in PRCs. We correlate the identified harmonin subcellular expression and colocalization with the clinical phenotype observed in USH1C patients. Furthermore, we demonstrate a phenotype in primary cilia in patient-derived fibroblasts which we were able to revert by gene addition of harmonin a1. Our data provide novel insights for retinal cell biology, USH1C pathophysiology and subsequent gene therapy development.

Introduction Interviews are commonly used to select applicants for medical school, residency, and fellowship. However, interview techniques vary in acceptability, feasibility, reliability, and validity. This systematic review investigated the effectiveness of different interview methods in selecting the best qualified applicants for admission to medical school and developed a logic model to implement best practices for interviewing. Methods Five electronic literature databases were searched for comparative studies related to interviewing in medical schools from inception through February 1, 2021. Inclusion criteria included publications in English that compared different methods of conducting a selection interview in medical schools with a controlled trial design. General study characteristics, measurement methodologies, and outcomes were reviewed. Quality appraisal was performed using the Medical Education Research Study Quality Instrument (MERSQI) and the Oxford Risk of Bias Scale. Based on these findings, a logic model was constructed using content analysis. Results Thirteen studies were included. The multiple mini-interview (MMI) was reliable, unbiased, and predicted clinical and academic performance; the virtual MMI increased reliability and lowered costs. For unstructured interviews, blinding interviewers to academic scores reduced bias towards higher scorers; student and faculty interviewers rated applicants similarly. Applicants preferred structured over unstructured interviews. Study quality was above average per the MERSQI, risk of bias was high per the Oxford scale, and between-study heterogeneity was substantial. Discussion There were few high-quality studies on interviewing applicants for admission to medical school; the MMI appears to offer a reliable method of interviewing. A logic model can provide a conceptual framework for conducting evidence-based admissions interviews.