Biology subjects

Tomita, A.

Publications and source records attributed to Tomita, A..

5 recordsLinked to original sources

bioRxiv2026

Selective depletion of AMH-expressing granulosa cells in vivo impairs follicular development and fertility in female mice

In mammals, ovarian follicle development is a highly coordinated process that underlies female fertility. Granulosa cells expressing anti-Mullerian hormone (AMH) are widely used as a marker of growing follicles. However, the in vivo roles of granulosa cells in follicular development and female fertility remain unclear. Here, we analyzed AMH-toxin receptor-mediated cell knockout (AMH-TRECK) transgenic (Tg) mice on a NOG background, in which AMH-expressing granulosa cells are specifically depleted by diphtheria toxin (DT). We first found that, after a single DT injection into postnatal AMH-TRECK Tg females, AMH-expressing granulosa cells in primary and secondary follicles exhibited cleaved caspase-3 signals 1 day later and were depleted 4 days later. Second, after repeated DT injections weekly from 1 to 7 weeks of age in AMH-TRECK Tg females, antral follicles and corpora lutea were rarely observed, and the numbers of primordial, primary, and secondary follicles were decreased. Following PMSG and hCG stimulation, repeated DT-injected Tg females exhibited a reduced number of ovulated oocytes with a low proportion of mature oocytes, resulting in reduced IVF rates and fertility. Further, after a cessation of repeated DT treatment, ovarian weight and follicular development recovered: the numbers of primary, secondary, and antral follicles were recovered, whereas the primordial follicle pool remains reduced. We conclude that selective depletion of AMH-expressing granulosa cells in vivo impairs follicular development and fertility. Our model enables assessment of the in vivo effects of granulosa cell depletion and may provide a useful platform for future transplantation-based studies to understand complex follicular dynamics.

developmental biology↗

bioRxiv2025

Systematic measurements of dose-dependent responses for combinatorial treatments of SA and JA led to the development of transcriptomic biomarkers

Plants coordinate defence against pathogens and herbivores through the crosstalk between salicylic acid (SA) and jasmonic acid (JA) signalling pathways. However, little is known about how plants integrate the phytohormone concentration profiles to shape defence states in complex field environments. Here we show that systematically varying combinatorial SA and JA concentrations in Arabidopsis thaliana reveals 43 distinct combination-specific transcriptional signatures beyond SA-JA antagonism. Leveraging these data, we developed and validated machine-learning-based transcriptomic biomarkers that enabled independent quantification of SA and JA response states. By applying these biomarkers to field-grown A. thaliana, we revealed that SA/JA response states were dynamically shaped by abundant and co-occurrence of herbivores on individual plants. Our study provides a strategy to decode hormonal responses to biotic environments from field transcriptomes, bridging the gap between molecular signalling and ecological dynamics.

plant biology↗

bioRxiv2024

Microglial engulfing of glutamatergic inputs and diminished excitability of D1 medium spiny neurons of the nucleus accumbens by peripheral inflammatory insult

Neuroimmune responses to systemic inflammation can generate anxiodepressive behaviors and psychomotor slowing. The nucleus accumbens (NAc) is a neural hub encoding mood and motivation that contributes to the locomotor and mood dampening effects of neuroinflammation. Dopamine receptor 1 mediums spiny neurons (D1-MSNs) of the NAc regulate locomotor activity, motivated behavior and emotional states and are modulated by microglial reactivity. Here, we evaluated sickness- and anxiety-like behaviors along with D1-MSN activity and microglial responses in the NAc to systemic lipopolysaccharide (LPS) administration. LPS stimulated anxiety-like behavior, blunted locomotion and reduced cFos expression in D1-MSNs of the NAc core and shell of male mice. These effects associated with reduced excitatory inputs (EPSCs) onto D1-MSNs as measured by whole cell patch-clamp. To determine if microglia contribute to changes in MSN activity, Ca2+ imaging of primary cultures containing NAc neurons with or without primary NAc microglia was performed. The presence of microglia decreased the activity of LPS-treated MSNs in response to dopamine and glutamate application and LPS stimulated microglial phagocytosis of MSN processes in co-cultures. Immunohistochemical analyses revealed that in vivo LPS treatment enhanced morphological indices of microglia reactivity and engulfment of vesicular glutamate transporter 1 (VGLUT1) inputs in the NAc. Our results suggest that LPS reduces locomotion and stimulates anxiety via increasing microglia engulfment of excitatory inputs onto D1-MSNs, and highlight changes in NAc microglia phagocytic activity in the behavioral consequences of neuroinflammation.

neuroscience↗

bioRxiv2020

Cryo-EM structure of the MgtE Mg2+ channel pore domain in Mg2+-free conditions reveals cytoplasmic pore opening

MgtE is a Mg2+ channel conserved in organisms ranging from prokaryotes to eukaryotes, including humans, and plays an important role in Mg2+ homeostasis. The previously determined MgtE structures in the Mg2+-bound, closed state and structure-based functional analyses of MgtE revealed that the binding of Mg2+ ions to the MgtE cytoplasmic domain induces channel inactivation to maintain Mg2+ homeostasis. However, due to the lack of a structure of the MgtE channel, including its transmembrane domain in Mg2+-free conditions, the pore-opening mechanism of MgtE has remained unclear. Here, we determined the cryoelectron microscopy (cryo-EM) structure of the MgtE-Fab complex in the absence of Mg2+ ions. The Mg2+-free MgtE transmembrane domain structure and its comparison with the Mg2+-bound, closed-state structure, together with functional analyses, showed the Mg2+-dependent pore opening of MgtE on the cytoplasmic side and revealed the kink motions of the TM2 and TM5 helices at the glycine residues, which are important for channel activity. Overall, our work provides structure-based mechanistic insights into the channel gating of MgtE.

biophysics↗

bioRxiv2019

Gene Cascade Finder: A tool for identification of gene cascades and its application in Caenorhabditis elegans

Obtaining a comprehensive understanding of the gene regulatory networks, or gene cascades, involved in cell fate determination and cell lineage segregation in Caenorhabditis elegans is a long-standing challenge. Although RNA-sequencing (RNA-Seq) is a promising technique to resolve these questions, the bioinformatics tools to identify associated gene cascades from RNA-Seq data remain inadequate. To overcome these limitations, we developed Gene Cascade Finder (GCF) as a novel tool for building gene cascades by comparison of mutant and wild-type RNA-Seq data along with integrated information of protein-protein interactions, expression timing, and domains. Application of GCF to RNA-Seq data confirmed that SPN-4 and MEX-3 regulate the canonical Wnt pathway during embryonic development. Moreover, lin-35, hsp-3, and gpa-12 were found to be involved in MEX-1-dependent neurogenesis, and MEX-3 was found to control the gene cascade promoting neurogenesis through lin-35 and apl-1. Thus, GCF could be a useful tool for building gene cascades from RNA-Seq data.

genomics↗