Biology subjects

Nishiguchi, K. M.

Publications and source records attributed to Nishiguchi, K. M..

3 recordsLinked to original sources

bioRxiv2020

Improved daylight vision following AAV-mediated expression of R9AP in murine rod photoreceptors

Cone photoreceptors mediate daylight vision and are the primary cells responsible for vision in humans. Cone dysfunction leads to poor quality daylight vision because rod photoreceptors become saturated and non-functional at high light levels. Here we demonstrate that in mice lacking cone function, AAV-mediated over-expression of Rgs9-anchor protein (R9AP), a critical component of the GTPase complex that mediates the deactivation of the phototransduction cascade, results in desensitization of rod function and a "photopic shift" of the rod-driven electroretinogram. This treatment enables rods to respond to brighter light (up to [~]2.0 log) with increased visually-evoked cortical responses to high intensity stimulation. These results suggest that AAV-mediated transfer of R9ap into rods might be used to improve daylight vision in humans visually handicapped by cone dysfunction.

bioengineering↗

bioRxiv2019

Systematic detection of Mendelian and non-Mendelian variants associated with retinitis pigmentosa by genome-wide association study

To uncover genetic basis of autosomal recessive retinitis pigmentosa (ARRP), we applied 2-step genome-wide association study (GWAS) in 640 Japanese patients prescreened with targeted re-sequencing. Meta-GWAS identified three independent peaks at P < 5.0x10-8, all within the major ARRP gene EYS. Two were each tagged by a low frequency variant (allele frequency < 0.05); a known founder Mendelian mutation (c.4957dupA, p.S1653Kfs*2) and a presumably hypomorphic non-synonymous variant (c.2528G>A, p.G843E). c.2528G>A newly solved 7.0% of Japanese ARRP cases, improving genetic diagnosis by 26.8% and simultaneously serving as a new attractive target for genome editing gene therapy. The third peak was tagged by an intronic common variant, representing a novel disease-susceptibility signal. GWAS successfully unraveled genetic causes of a rare "monogenic" disorder for the first time, which provided unexpected insights into significant contribution of non-Mendelian genetic factors and identified a novel high frequency variant directly linked to development of local genome therapeutics.

genetics↗

bioRxiv2018

Frequent variants in the Japanese population determine quasi-Mendelian inheritance of rare retinal ciliopathy

Hereditary retinal degenerations (HRDs) are Mendelian diseases characterized by progressive blindness and caused by ultra-rare mutations. In a genomic screen of 331 unrelated Japanese patients, we identify a disruptive Alu insertion and a nonsense variant (p.Arg1933*) in the ciliary gene RP1, neither of which are rare alleles in Japan. p.Arg1933* is almost polymorphic (frequency = 0.6%, amongst 12,000 individuals), does not cause disease in homozygosis or heterozygosis, and yet is significantly enriched in HRD patients (frequency = 2.1%, i.e. a 3.5-fold enrichment; p-value = 9.2x10-5). Familial co-segregation and association analyses show that p.Arg1933* can act as a Mendelian mutation, in trans with the Alu insertion, but might also cause disease in association with two alleles in the EYS gene in a non-Mendelian pattern of heredity. Our results suggest that rare conditions such as HRDs can be paradoxically determined by relatively common variants, following a quasi-Mendelian model linking monogenic and complex inheritance.

genomics↗