Performance of ChatGPT in Board Examinations for Specialists in the Japanese Ophthalmology Society.

We investigated the potential of ChatGPT in the ophthalmological field in the Japanese language using board examinations for specialists in the Japanese Ophthalmology Society. We tested GPT-3.5 and GPT-4-based ChatGPT on five sets of past board examination problems in July 2023. Japanese text was used as the prompt adopting two strategies: zero- and few-shot prompting. We compared the correct answer rate of ChatGPT with that of actual examinees, and the performance characteristics in 10 subspecialties were assessed. ChatGPT-3.5 and ChatGPT-4 correctly answered 112 (22.4%) and 229 (45.8%) out of 500 questions with simple zero-shot prompting, respectively, and ChatGPT-4 correctly answered 231 (46.2%) questions with few-shot prompting. The correct answer rates of ChatGPT-3.5 were approximately two to three times lower than those of the actual examinees for each examination set (p = 0.001). However, the correct answer rates for ChatGPT-4 were close to approximately 70% of those of the examinees. ChatGPT-4 had the highest correct answer rate (71.4% with zero-shot prompting and 61.9% with few-shot prompting) in "blepharoplasty, orbit, and ocular oncology," and the lowest answer rate (30.0% with zero-shot prompting and 23.3% with few-shot prompting) in "pediatric ophthalmology." We concluded that ChatGPT could be one of the advanced technologies for practical tools in Japanese ophthalmology.

Robotic search for optimal cell culture in regenerative medicine.

Induced differentiation is one of the most experience- and skill-dependent experimental processes in regenerative medicine, and establishing optimal conditions often takes years. We developed a robotic AI system with a batch Bayesian optimization algorithm that autonomously induces the differentiation of induced pluripotent stem cell-derived retinal pigment epithelial (iPSC-RPE) cells. From 200 million possible parameter combinations, the system performed cell culture in 143 different conditions in 111 days, resulting in 88% better iPSC-RPE production than that obtained by the pre-optimized culture in terms of the pigmentation scores. Our work demonstrates that the use of autonomous robotic AI systems drastically accelerates systematic and unbiased exploration of experimental search space, suggesting immense use in medicine and research.

Automated evaluation of retinal pigment epithelium disease area in eyes with age-related macular degeneration.

The retinal pigment epithelium (RPE) is essential for the survival and function of retinal photoreceptor cells. RPE dysfunction causes various retinal diseases including age-related macular degeneration (AMD). Clinical studies on ES/iPS cell-derived RPE transplantation for RPE dysfunction-triggered diseases are currently underway. Quantification of the diseased RPE area is important to evaluate disease progression or the therapeutic effect of RPE transplantation. However, there are no standard protocols. To address this issue, we developed a 2-step software that enables objective and efficient quantification of RPE-disease area changes by analyzing the early-phase hyperfluorescent area in fluorescein angiography (FA) images. We extracted the Abnormal region. This extraction was based on deep learning-based discrimination. We scored the binarized extracted area using an automated program. Our program's performance for the same eye from the serial image captures was within 3.1 ± 7.8% error. In progressive AMD, the trend was consistent with human assessment, even when FA images from two different visits were compared. This method was applicable to quantifying RPE-disease area changes over time, evaluating iPSC-RPE transplantation images, and a disease other than AMD. Our program may contribute to the assessment of the clinical course of RPE-disease areas in routine clinics and reduce the workload of researchers.

A Variable Scheduling Maintenance Culture Platform for Mammalian Cells.

Cell culturing is a basic experimental technique in cell biology and medical science. However, culturing high-quality cells with a high degree of reproducibility relies heavily on expert skills and tacit knowledge, and it is not straightforward to scale the production process due to the education bottleneck. Although many automated culture systems have been developed and a few have succeeded in mass production environments, very few robots are permissive of frequent protocol changes, which are often required in basic research environments. LabDroid is a general-purpose humanoid robot with two arms that performs experiments using the same tools as humans. Combining our newly developed AI software with LabDroid, we developed a variable scheduling system that continuously produces subcultures of cell lines without human intervention. The system periodically observes the cells on plates with a microscope, predicts the cell growth curve by processing cell images, and decides the best times for passage. We have succeeded in developing a system that maintains the cultures of two HEK293A cell plates with no human intervention for 192 h.

A Microfluidic Platform Based on Robust Gas and Liquid Exchange for Long-term Culturing of Explanted Tissues.

Microfluidic devices are important platforms to culture and observe biological tissues. Compared with conventional setups, microfluidic devices have advantages in perfusion, including an enhanced delivery of nutrients and gases to tissues. However, explanted tissues can maintain their functions for only hours to days in microfluidic devices, although their observations are desired for weeks. The suprachiasmatic nucleus (SCN) is a brain region composed of heterogeneous cells to control the biological clock system through synchronizing individual cells in this region. The synchronized and complicated cell-cell interactions of SCN cells are difficult to reproduce from seeded cells. Thus, the viability of explanted SCN contributes to the study of SCN functions. In this paper, we propose a new perfusion platform combining a PDMS microfluidic device with a porous membrane to culture an explanted SCN for 25 days. We expect that this platform will provide a universal interface for microfluidic manipulation of tissue explants.

Muscarinic Acetylcholine Receptors Chrm1 and Chrm3 Are Essential for REM Sleep.

Sleep regulation involves interdependent signaling among specialized neurons in distributed brain regions. Although acetylcholine promotes wakefulness and rapid eye movement (REM) sleep, it is unclear whether the cholinergic pathway is essential (i.e., absolutely required) for REM sleep because of redundancy from neural circuits to molecules. First, we demonstrate that synaptic inhibition of TrkA+ cholinergic neurons causes a severe short-sleep phenotype and that sleep reduction is mostly attributable to a shortened sleep duration in the dark phase. Subsequent comprehensive knockout of acetylcholine receptor genes by the triple-target CRISPR method reveals that a similar short-sleep phenotype appears in the knockout of two Gq-type acetylcholine receptors Chrm1 and Chrm3. Strikingly, Chrm1 and Chrm3 double knockout chronically diminishes REM sleep to an almost undetectable level. These results suggest that muscarinic acetylcholine receptors, Chrm1 and Chrm3, are essential for REM sleep.

Enhanced transgene expression by plasmid-specific recruitment of histone acetyltransferase.

Histone acetylation is associated with the activation of genes on chromosomes. Transgene expression from plasmid DNA might be increased by the acetylation of histones bound to plasmid DNA. To examine this hypothesis, we employed a positive feedback system, using a fusion protein of the sequence-specific DNA binding domain of yeast GAL4 and the histone acetyltransferase (HAT) domain of mouse CREB-binding protein (GAL4-HAT), in which GAL4-HAT promotes its own expression as well as that of a reporter gene product (luciferase). The activator plasmid DNA carrying the gene encoding GAL4-HAT was introduced into mouse Hepa1-6 cells, together with the reporter plasmid DNA, by lipofection. Significantly increased luciferase expression was observed by the co-introduction of the activator plasmid DNA. Moreover, the acetylation of histones bound to the reporter plasmid DNA was enriched by the activator plasmid DNA. These results indicated that the GAL4-HAT system is useful for enhanced transgene expression.

Mass spectrometry-based absolute quantification reveals rhythmic variation of mouse circadian clock proteins.

Absolute values of protein expression levels in cells are crucial information for understanding cellular biological systems. Precise quantification of proteins can be achieved by liquid chromatography (LC)-mass spectrometry (MS) analysis of enzymatic digests of proteins in the presence of isotope-labeled internal standards. Thus, development of a simple and easy way for the preparation of internal standards is advantageous for the analyses of multiple target proteins, which will allow systems-level studies. Here we describe a method, termed MS-based Quantification By isotope-labeled Cell-free products (MS-QBiC), which provides the simple and high-throughput preparation of internal standards by using a reconstituted cell-free protein synthesis system, and thereby facilitates both multiplexed and sensitive quantification of absolute amounts of target proteins. This method was applied to a systems-level dynamic analysis of mammalian circadian clock proteins, which consist of transcription factors and protein kinases that govern central and peripheral circadian clocks in mammals. Sixteen proteins from 20 selected circadian clock proteins were successfully quantified from mouse liver over a 24-h time series, and 14 proteins had circadian variations. Quantified values were applied to detect internal body time using a previously developed molecular timetable method. The analyses showed that single time-point data from wild-type mice can predict the endogenous state of the circadian clock, whereas data from clock mutant mice are not applicable because of the disappearance of circadian variation.

Anatomy of plasmid DNAs with anti-silencing elements.

The transience of transgene expression is a major obstacle in the development of nonviral vectors. The CpG-free and pLIVE plasmids reportedly achieve long-term transgene expression in mouse liver. In this work, the anti-silencing elements within these plasmids were studied. The effects of plasmid that was being silenced on transgene expression from the CpG-free plasmid and those of transgene expression at early time points on silencing were also examined. The results suggested that the backbone sequence of the CpG-free plasmid and the 3' untranslated region of the albumin gene of the pLIVE plasmid contribute to durable expression. In addition, no influence of the silencing of another plasmid on the duration of CpG-free plasmid expression or of transgene expression at early time points on silencing was detected.

Enhanced transgene expression from chromatinized plasmid DNA in mouse liver.

Plasmid DNA was chromatinized with core histones (H2A, H2B, H3, and H4) in vitro and was delivered into mouse liver by hydrodynamics-based administration. Transgene expression from the chromatinized plasmid DNA was more efficient than that from plasmid DNA delivered in the naked form. The use of acetylation-enriched histones isolated from cells treated with a histone deacetylase inhibitor (trichostatin A) seemed to be more effective. These results indicated that chromatinized plasmid DNA is useful for efficient transgene expression in vivo.

Effects of endogenous proteins and microRNA target sequence in a positive feedback system.

A positive feedback system, using GAL4-vp16 (a fusion protein of yeast GAL4 and herpes simplex virus vp16) as an activator and firefly luciferase as a reporter, maintained luciferase expression for 7 d in mice. However, the luciferase expression decreased after 7 d, and this phenomenon could be caused by immunoreactions against these exogenous proteins. This hypothesis was examined by the following three strategies, designed to avoid the putative immunoreactions: (i) use of the endogenous secreted alkaline phosphatase (SEAP) protein as a reporter, (ii) replacement of vp16 with endogenous transcription factors, and (iii) insertion of the target sequence of microRNA expressed in cells of hematopoietic origin, to suppress GAL4-vp16 expression in antigen-presenting cells. The results obtained in this study suggested that silencing would be induced by mechanism(s) besides immunoreactions against reporter and activator proteins.