Biology subjects

Yokoyama, C.

Publications and source records attributed to Yokoyama, C..

4 recordsLinked to original sources

bioRxiv2025

The sympathoadrenal contribution to inferior vena cava formation

Vascular development is fundamental during embryogenesis. Although the molecular and cellular mechanisms of vascular formation have been extensively studied, the developmental basis common to anatomical variations in major veins remains poorly understood1-4. In particular, the renal segment of the inferior vena cava (IVC) exhibits marked anatomical variability, and these structural differences often affect the safety of retroperitoneal surgeries5,6. Here we show that the renal segment of the IVC in mouse embryos does not arise from the subcardinal vein (SubCV), as classically proposed7, but instead forms from a vascular plexus in the para-aortic ridge (PAR) closely associated with developing sympathetic and adrenal tissues. Three-dimensional imaging with molecular markers revealed the vascular plexus in PAR arises independently of the SubCV and develops in Zuckerkandl organ and adrenal gland primordia. Moreover, genetic models demonstrated that the development of the sympathetic and adrenal tissues contributes to the organization and remodeling of this vascular network. This sympathoadrenal contribution contrasts with the classical mesonephros-centric model and explains the consistent IVC structures observed even in the absence of renal development. Our findings suggest a mammal-specific mode of IVC formation driven by the emergence of dominant sympathetic paraganglia and reduced reliance on mesonephric filtration. This revised developmental framework provides insight into the evolutionary divergence of venous anatomy and may help interpret clinically significant vascular variations during abdominal surgery.

developmental biology↗

bioRxiv2022

The shh limb enhancer is activated in patterned limb regeneration but not in hypomorphic limb regeneration in Xenopus laevis

Xenopus young tadpoles regenerate a limb with the anteroposterior (AP) pattern, but metamorphosed froglets regenerate a hypomorphic limb after amputation. The key gene for AP patterning, shh, is expressed in a regenerating limb of the tadpole but not in that of the froglet. Genomic DNA in the shh limb-specific enhancer, MFCS1 (ZRS), is hypermethylated in froglets but hypomethylated in tadpoles: shh expression may be controlled by epigenetic regulation of MFCS1. Is MFCS1 specifically activated for regenerating the AP-patterned limb? We generated transgenic Xenopus laevis lines that visualize the MFCS1 enhancer activity with a GFP reporter. The transgenic tadpoles showed GFP expression in hoxd13- and shh-expressing domains of developing and regenerating limbs, whereas the froglets showed no GFP expression in the regenerating limbs despite having hoxd13 expression. Genome sequence analysis and co-transfection assays using cultured cells revealed that Hoxd13 can activate Xenopus MFCS1. These results suggest that MFCS1 activation correlates with regeneration of AP-patterned limbs and that re-activation of epigenetically inactivated MFCS1 would be crucial to confer the ability to non-regenerative animals for regenerating a properly patterned limb.

developmental biology↗

bioRxiv2022

Anatomical variability, multi-modal coordinate systems, and precision targeting in the marmoset brain

Localising accurate brain regions needs careful evaluation in each experimental species due to their individual variability. However, the function and connectivity of brain areas is commonly studied using a single-subject cranial landmark-based stereotactic atlas in animal neuroscience. Here, we address this issue in a small primate, the common marmoset, which is increasingly widely used in systems neuroscience. We developed a non-invasive multi-modal neuroimaging-based targeting pipeline, which accounts for intersubject anatomical variability in cranial and cortical landmarks in marmosets. This methodology allowed creation of multi-modal templates (MarmosetRIKEN20) including head CT and brain MR images, embedded in coordinate systems of anterior and posterior commissures (AC-PC) and CIFTI grayordinates. We found that the horizontal plane of the stereotactic coordinate was significantly rotated in pitch relative to the AC-PC coordinate system (10 degrees, frontal downwards), and had a significant bias and uncertainty due to positioning procedures. We also found that many common cranial and brain landmarks (e.g., bregma, intraparietal sulcus) vary in location across subjects and are substantial relative to average marmoset cortical area dimensions. Combining the neuroimaging-based targeting pipeline with robot-guided surgery enabled proof-of-concept targeting of deep brain structures with an accuracy of 0.2 mm. Altogether, our findings demonstrate substantial intersubject variability in marmoset brain and cranial landmarks, implying that subject-specific neuroimaging-based localization is needed for precision targeting in marmosets. The population-based templates and atlases in grayordinates, created for the first time in marmoset monkeys, should help bridging between macroscale and microscale analyses. HighlightsO_LIAchieved sub-millimeter localization accuracy of subject-wise brain region C_LIO_LIPropose a dedicated non-invasive multi-modal subject-specific registration pipeline C_LIO_LIConstruct brain coordinate system in AC-PC and grayordinate spaces C_LIO_LIEstablish multi-modal MRI and CT brain and cortical templates, MarmosetRIKEN20 C_LIO_LIQuantify intersubject variabilities in marmoset brain C_LIO_LISignificant bias and uncertainty exist in marmoset stereotactic positioning C_LI

neuroscience↗

bioRxiv2020

Personality, Subjective Well-Being, and the Serotonin 1a Receptor Gene in Common Marmosets (Callithrix jacchus)

Studies of personality traits in common marmosets (Callithrix jacchus) indicate that there are five or six constructs--sociability, dominance, neuroticism, openness, and two related to conscientiousness--that define personality in common marmosets. The present study attempted to determine whether our earlier study of laboratory-housed individuals only yielded three domains--Dominance, Sociability, and Neuroticism--because of a low amount of between-subjects variance. We therefore increased our sample size from 77 to 128. In addition, we ascertained the reliability and validity of ratings and whether polymorphisms related to the serotonin 1a receptor were associated with personality. We found Sociability, Dominance, and Negative Affect factors that resembled three domains found in previous studies, including ours. We also found an Openness and Impulsiveness factor, the latter of which bore some resemblance to Conscientiousness, and two higher-order factors, Pro-sociality and Boldness. Further analyses could not exclude the possibility that Pro-sociality and Boldness represented a higher-level of personality organization. Correlations between personality factors and well-being were consistent with the definitions of the factors. There were no significant associations between personality and genotype. These results are consistent with the possibility that common marmoset personality structure varies as a function of rearing or housing variables that have not yet been investigated systematically.

animal behavior and cognition↗