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Biology subjects

Okabe, M.

Publications and source records attributed to Okabe, M..

7 recordsLinked to original sources

Trajectory Inference for Multi-Omics Data Using Ordered Labels

Trajectory inference (TI) has emerged as a crucial approach for understanding cellular development and differentiation processes. By reconstructing the temporal ordering of individual cells, TI can analyze the mechanisms underlying development and disease progression. Various TI methods have been proposed and applied across diverse fields, including cancer research and immunology. However, most existing methods rely solely on gene expression data and do not incorporate other omics information such as DNA methylation, chromatin accessibility, and protein expression. To address this limitation, approaches that integrate multiple omics datasets for TI have been proposed. Nevertheless, these methods typically assume the use of only common variables across datasets, making it difficult to align heterogeneous data with differing measurement targets across omics layers. This limitation can lead to information loss and challenges in capturing interactions between different omics datasets, which may reduce integration accuracy. In this study, we propose a novel TI method that captures interactions among variables across different omics layers and accommodates unpaired datasets with non-overlapping measurement targets. By effectively capturing relationships between different omics layers, our approach enables a more comprehensive multi-omics TI framework, thus providing deeper insights into cellular development.

bioinformatics↗

Biosynthesis of gibberellin-related compounds modulates far-red light responses in the liverwort Marchantia polymorpha

The phytohormone gibberellins (GAs) are key regulators of growth, development and environmental responses in angiosperms. From an evolutionary perspective, all major steps of GA biosynthesis are conserved among vascular plants, while GA biosynthetic intermediates such as ent-kaurenoic acid (KA) are also produced by bryophytes. Here we show that in the liverwort Marchantia polymorpha, KA and GA12 are synthesized by evolutionarily conserved enzymes, which are required for developmental responses to far-red light (FR). Under FR-enriched conditions, mutants of various biosynthesis enzymes consistently altered thallus growth allometry, delayed the initiation of gametogenesis, and affected the morphology of gamete-bearing structures (gametangiophores). By chemical treatments and LC-MS/MS analyses, we confirmed these phenotypes were caused by deficiency of some GA-related compounds derived from KA, but not bioactive GAs from vascular plants. Transcriptome analysis showed that FR enrichment induced the up-regulation of genes related to stress responses and secondary metabolism in M. polymorpha, which was largely dependent on the biosynthesis of GA-related compounds. Due to the lack of the canonical GA receptors in bryophytes, we hypothesize that GA-related compounds are commonly synthesized in land plants but co-opted independently to regulate responses to light quality change in different lineages during the past 450 million years of evolution.

plant biology↗

Latent taste diversity revealed by a vertebrate-wide catalogue of T1R receptors

Taste is a vital chemical sense for feeding behavior. In mammals, the umami and sweet taste receptors are composed of three members of the taste receptor type 1 (T1R/TAS1R) family: T1R1, T1R2, and T1R3. Because their functional homologs exist in teleosts, only three TAS1R genes generated by gene duplication are believed to have been inherited from the common ancestor of bony vertebrates. Here, we report five previously uncharacterized TAS1R members in vertebrates, named TAS1R4, 5, 6, 7, and TAS1Rcf, through a genome-wide survey of diverse taxa. For TAS1R2 and TAS1R3, mammalian and teleost fish genes were found to be paralogous. Phylogenetic analysis suggests that the bony vertebrate ancestor had nine TAS1Rs due to multiple gene duplications, and some TAS1Rs were lost independently in each lineage; ultimately, mammals and teleosts have retained only three TAS1Rs, whereas other lineages have retained more TAS1Rs. Functional assays and expression analysis in non-teleost fishes suggest that the novel T1Rs form heterodimers in taste receptor cells and contribute to the recognition of a broad range of ligands such as essential amino acids, including branched-chain amino acids, which were not previously considered as T1R ligands. These results highlight an unexpected diversity of taste sensations in both modern and the ancestors of vertebrates. The complex evolution of the taste receptor family might have enabled vertebrates to adapt to diverse habitats on Earth.

evolutionary biology↗

Lung evolution in vertebrates and the water-to-land transition

A crucial evolutionary change in vertebrate history was the Palaeozoic (Devonian ~400 million years ago) water-to-land transition, allowed by key morphological and physiological modifications including the acquisition of lungs. Nonetheless, the origin and early evolution of vertebrate lungs remain highly controversial, particularly whether the ancestral state was paired or unpaired. Due to the rarity of fossil soft tissue preservation, lung evolution can only be traced based on the extant phylogenetic bracket. Here we investigate, for the first time, lung morphology in extensive developmental series of key living lunged osteichthyans using synchrotron X-ray microtomography and histology. Our results shed light on the primitive state of vertebrate lungs as unpaired, evolving to be truly paired in the lineage towards the tetrapods. The water-to-land transition confronted profound physiological challenges and paired lungs were decisive for increasing the surface area and the pulmonary compliance and volume, especially during the air-breathing on land.

evolutionary biology↗

Visual discrimination of optical material properties: a large-scale study

Complex visual processing involved in perceiving the object materials can be better elucidated by taking a variety of research approaches. Sharing stimulus and response data is an effective strategy to make the results of different studies directly comparable and can assist researchers with different backgrounds to jump into the field. Here, we constructed a database containing several sets of material images annotated with visual discrimination performance. We created the material images using physically-based computer graphics techniques and conducted psychophysical experiments with them in both laboratory and crowdsourcing settings. The observers task was to discriminate materials on one of six dimensions (gloss contrast, gloss distinctness-of-image, translucent vs. opaque, metal vs. plastic, metal vs. glass, and glossy vs. painted). The illumination consistency and object geometry were also varied. We used a non-verbal procedure (an oddity task) applicable for diverse use-cases such as cross-cultural, cross-species, clinical, or developmental studies. Results showed that the material discrimination depended on the illuminations and geometries and that the ability to discriminate the spatial consistency of specular highlights in glossiness perception showed larger individual differences than in other tasks. In addition, analysis of visual features showed that the parameters of higher-order color texture statistics can partially, but not completely, explain task performance. The results obtained through crowdsourcing were highly correlated with those obtained in the laboratory, suggesting that our database can be used even when the experimental conditions are not strictly controlled in the laboratory. Several projects using our dataset are underway.

neuroscience↗

The reactivation of reprogramming factors within human blastocysts by using ATP contribute to human blastocyst development

Scientists worldwide have been unable to replicate the stimulus-triggered acquisition of pluripotency (STAP) cells and/or the STAP phenomenon. However, investigations into STAP cells and/or the STAP phenomenon by RIKEN CDB in Japan found that ATP (adenosine 5-triphosphate disodium salt hydrate) can upregulate Oct3/4 (POU5F1: POU domain, class 5, transcription factor 1) and Nanog mRNA expression in mouse hepatocytes.\n\nOn the other hand, no studies have investigated whether ATP can contribute to human blastocyst development. Here we show the reactivation of reprogramming factors within human blastocysts by appropriate ATP treatment (1 mM for 2 days) can contribute to human blastocyst development.\n\nIn conclusion, although ATP treatment could not replicate STAP cells and/or the STAP phenomenon by scientists worldwide, appropriate ATP treatment (1 mM for 2 days) in cultured human blastocysts with totipotency would be helpful for infertility women.

developmental biology↗

Beyond the limitation of randomized controlled trials (RCTs)-current drug repositioning by using human induced pluripotent stem (iPS) cells technology-

To ensure the clinical value of medical interventions, randomized controlled trials (RCTs) are necessary. However, the results of conventional RCTs cannot show individual therapeutic efficacy and safety for medical intervention to a targeted patient. It is the most important weak point of conventional RCTs. Here I show that the new clinical research method by using human induced pluripotent stem (iPS) cells technology will be able to complement the most important weak point of conventional RCTs.\n\nAs the representative examples, I show the new clinical values of statins (inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase) found by using human iPS cells technology in achondroplasia or hanatophoric dysplasia (type 1) case and hepatitis C virus (HCV) infection case. Furthermore, they are also important examples for drug repositioning.\n\nTherefore, my article would be valuable as a scientific communication for physicians and/or scientists.

scientific communication and education↗