Tachykinins Stimulate a Subset of Mouse Taste Cells

The tachykinins substance P (SP) and neurokinin A (NKA) are present in nociceptive sensory fibers expressing transient receptor potential cation channel, subfamily V, member 1 (TRPV1). These fibers are found extensively in and around the taste buds of several species. Tachykinins are released from nociceptive fibers by irritants such as capsaicin, the active compound found in chili peppers commonly associated with the sensation of spiciness. Using real-time Ca2+-imaging on isolated taste cells, it was observed that SP induces Ca2+ -responses in a subset of taste cells at concentrations in the low nanomolar range. These responses were reversibly inhibited by blocking the SP receptor NK-1R. NKA also induced Ca2+-responses in a subset of taste cells, but only at concentrations in the high nanomolar range. These responses were only partially inhibited by blocking the NKA receptor NK-2R, and were also inhibited by blocking NK-1R indicating that NKA is only active in taste cells at concentrations that activate both receptors. In addition, it was determined that tachykinin signaling in taste cells requires Ca2+-release from endoplasmic reticulum stores. RT-PCR analysis further confirmed that mouse taste buds express NK-1R and NK-2R. Using Ca2+-imaging and single cell RT-PCR, it was determined that the majority of tachykinin-responsive taste cells were Type I (Glial-like) and umami-responsive Type II (Receptor) cells. Importantly, stimulating NK-1R had an additive effect on Ca2+ responses evoked by umami stimuli in Type II (Receptor) cells. This data indicates that tachykinin release from nociceptive sensory fibers in and around taste buds may enhance umami and other taste modalities, providing a possible mechanism for the increased palatability of spicy foods

Repair of the TGFBI gene in human corneal keratocytes derived from a granular corneal dystrophy patient via CRISPR/Cas9-induced homology-directed repair

Abstract Granular corneal dystrophy (GCD) is an autosomal dominant hereditary disease in which multiple discrete and irregularly shaped granular opacities are deposited in the corneal stroma. GCD is caused by a point mutation in the transforming growth factor-β-induced (TGFBI) gene, located on chromosome 5q31. Here, we report the first successful application of CRISPR-Cas9-mediated genome editing for the correction of a TGFBI mutation in GCD patient-derived primary corneal keratocytes via homology-directed repair (HDR). To correct genetic defects in GCD patient cells, we designed a disease-specific guide RNA (gRNA) targeting the R124H mutation of TGFBI, which causes GCD type 2 (GCD2). An R124H mutation in primary human corneal keratocytes derived from a GCD2 patient was corrected by delivering a CRISPR plasmid expressing Cas9/gRNA and a single-stranded oligodeoxynucleotide HDR donor template in vitro. The gene correction efficiency was 20.6% in heterozygous cells and 41.3% in homozygous cells. No off-target effects were detected. These results reveal a new therapeutic strategy for GCD2; this method may also be applicable to other heredity corneal diseases

Supplementary Material for: A case of inflammatory juvenile conjunctival nevus with a rare histopathological type

Introduction Inflammatory juvenile conjunctival nevus (IJCN) is a rare condition affecting both children and adolescents. It has misleading clinical and histopathological features; therefore, careful assessment is necessary. We present a case of IJCN with a rare pathological type and misleading histopathological features. Case Presentation A 13-year-old girl with IJCN in the right eye was treated with antiallergic and steroid eye drops but showed no response and was referred to our hospital for excisional biopsy. Slit-lamp examination revealed a nonpigmented juxtalimbal tumor in the right eye. Histopathologically, nevus cells with mild nuclear atypia proliferated within conjunctival epithelium. Confluent growth of junctional nests, conjunctival cysts and a prominent inflammatory infiltration were also observed. Considering the young age of the patient and immunohistochemical characteristics (HMB-45, SOX10, p16 and Ki-67), this case was finally diagnosed as IJCN. IJCN has three pathological subtypes; compound, subepithelial and junctional, depending on the location of the nevus cells. This case was diagnosed as a rare junctional type, as most of the sections we examined showed lesions only within the epithelium, and none clearly showed lesions extending beneath the epithelium. Conclusion Pathological diagnosis of IJCN is difficult because some features of IJCN suggests malignancy. Detailed microscopic examination, immunohistochemical staining, and the patient’s young age could help render a final diagnosis