Biology subjects

Osakada, F.

Publications and source records attributed to Osakada, F..

12 recordsLinked to original sources

bioRxiv2026

Membrane progesterone receptors PAQR6 and PAQR8 in the ruminant uterus and ovary

Progesterone governs the establishment and maintenance of pregnancy in ruminants, acting through the nuclear progesterone receptor (PGR) and, potentially, through membrane progesterone receptors (mPRs) of the PAQR family. The cellular distribution of mPRs in ruminant reproductive tissues, however, remains undefined. We generated and validated rabbit polyclonal antibodies against the intracellular C-terminal peptides of bovine PAQR6 (mPR{delta}) and PAQR8 (mPR{beta}), and used them, with quantitative PCR of the uterus and conceptus, to map these receptors in the ovine uterus and conceptus and in the bovine ovary. Both antisera showed high ELISA titer against their immunizing peptides, negligible preimmune reactivity, and complete loss of tissue signal after peptide pre-absorption. By qPCR, PAQR6, PAQR8 and PGR transcript levels did not change significantly across the peri-implantation period in either the conceptus or the endometrium; in contrast, the progesterone-responsive gene ZBTB16 increased markedly in the conceptus (up to ~45-fold by day 21, p < 0.05 at days 17, 19 and 21), whereas FKBP5 showed a numerical increase without reaching statistical significance. Both genes remained relatively stable in the endometrium, indicating conceptus-specific changes in progesterone-responsive gene expression. At the protein level, PAQR6 and PAQR8 localized to the luminal and glandular epithelium of the endometrium across the cycle and early pregnancy, and to follicular (granulosa) and luteal cells of the ovary. Dual immunofluorescence in the ovine endometrium showed that both PAQR6 and PAQR8 are enriched at the apical surface of the luminal epithelium and are spatially distinct from the basolateral adherens-junction marker E-cadherin. These results provide a protein-level map of PAQR6 and PAQR8 in the ruminant reproductive tract, identify the apical epithelial surface as a site of receptor enrichment, and show that the endometrial epithelium retains membrane progesterone receptors while progesterone-responsive gene expression changes dynamically in the conceptus during the peri-implantation period. The validated ruminant-reactive antibodies provide a resource for future functional studies.

developmental biology↗

bioRxiv2026

Cell-type-specific expression of classical and membrane progesterone receptors at the human maternal-fetal interface

Progesterone is essential for the establishment and maintenance of pregnancy, primarily through the classical nuclear progesterone receptor (PGR). However, progesterone also exerts rapid, non-genomic effects through membrane progesterone receptors, including members of the progestin and adipoQ receptor (PAQR) family, whose cellular distribution and potential roles at the human maternal-fetal interface remain poorly understood. We therefore sought to define the cell-type-specific expression landscape of classical and membrane progesterone receptors during early human pregnancy. We analyzed publicly available single-cell RNA-sequencing datasets of the first-trimester human maternal-fetal interface to characterize the expression of PGR and PAQR family members across trophoblast, immune, stromal, and vascular cell populations. Major expression patterns were examined across independent datasets and further assessed using spatial transcriptomic data. PGR expression was predominantly localized to decidual stromal and perivascular populations, whereas individual PAQR family members showed distinct cellular distributions. PAQR6 was enriched in decidual natural killer cells, PAQR7 was broadly expressed in trophoblast populations, PAQR8 was prominently expressed in fetal stromal and macrophage populations, including Hofbauer cells, and PAQR9 showed prominent enrichment in syncytiotrophoblasts. Selected cell-type-specific patterns were further supported by spatial transcriptomic analysis. These findings provide a cell-type-resolved framework for investigating how distinct progesterone receptor systems mediate progesterone signaling across maternal and fetal cellular compartments during early human placentation.

developmental biology↗

bioRxiv2026

Maternal progesterone signaling establishes lifelong oral homeostasis

Pregnancy is accompanied by profound endocrine remodeling, yet the mechanisms by which maternal hormonal signals establish long-term tissue homeostasis remain largely unknown. Here we identify maternal progesterone signaling as a developmental cue that establishes lifelong oral homeostasis through a hormone-lipid-microbiome axis. We show that the membrane progesterone receptor mPR{delta} is selectively expressed in the developing and maternal submandibular glands, where it mediates non-genomic progesterone signaling to promote epithelial differentiation by driving the selective mobilization of docosahexaenoic acid (DHA). Loss of this pathway disrupts salivary gland maturation, reshapes the oral microbial ecosystem through the selective expansion of Pasteurellaceae, and causes local inflammation as well as systemic metabolic dysfunction. Mechanistically, antibiotic treatment abolishes these phenotypes, whereas transfer of the oral microbiota recapitulates disease, demonstrating that developmental defects in the host are translated into long-term pathology through the oral microbiome. Remarkably, maternal--but not adult--DHA supplementation restores salivary gland development and microbial homeostasis and prevents adult disease phenotypes, identifying a critical developmental window during which oral homeostasis is durably established. Collectively, these findings reveal a previously unrecognized maternal endocrine mechanism that establishes lifelong host-microbiome homeostasis and identify developmental programming as a fundamental principle linking maternal physiology to adult health. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=188 SRC="FIGDIR/small/743932v1_ufig1.gif" ALT="Figure 1"> View larger version (56K): org.highwire.dtl.DTLVardef@178cc90org.highwire.dtl.DTLVardef@1be04beorg.highwire.dtl.DTLVardef@29759dorg.highwire.dtl.DTLVardef@1e89994_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2025

Thalamus-cortex interactions drive cell type-specific cortical development in human pluripotent stem cell-derived assembloids

The thalamus plays a pivotal role in the development and function of neural circuits in the cerebral cortex. However, how thalamus-cortex interactions influence human cortical development remains unknown primarily because of the inaccessibility of the human embryonic brain. Here, we demonstrate thalamus-dependent gene expression, circuit organization, and neural activity during corticogenesis using human thalamocortical assembloids (hThCAs). Human cortical and thalamic organoids (hCOs and hThOs) derived from induced pluripotent stem cells exhibited region-specific gene expression and spontaneous neuronal activity. Upon the fusion of these organoids, hThCAs reconstructed reciprocal thalamus-cortex axonal projections and synaptic connections. Transcriptomic analysis revealed thalamus-dependent acceleration of cortical maturation, with upregulation of programs linked to axon development, subplate/cortical plate identity, and activity-regulated genes. Histological analysis showed expanded progenitor pools and increased deep-layer neurons within hThCAs. Wide-field Ca2+ imaging demonstrated that wave-like activity originated in the thalamic region and propagated to the cortical region. Furthermore, two-photon Ca2+ imaging of cortical neurons revealed that synchronous activity emerged exclusively in pyramidal tract (PT) and corticothalamic (CT) neurons, whereas intratelencephalic (IT) neurons remain asynchronous, highlighting cell type-specific circuit integration within hThCAs. These synchronized events were absent in isolated hCOs or in cortico-cortical assembloids, underscoring the specificity of thalamic input. Our findings suggest that diffusible thalamic cues broadly enhance progenitor expansion, while long-range thalamic input organizes cell type-specific synchronous activity. This study demonstrates the thalamus-dependent acquisition of mature cortical phenotypes in a cell type-specific manner in hThCAs, establishing developmental mechanisms linking regional interactions and cell type-specific circuit specification. Thus, hThCAs provide a tractable human platform for dissecting human-specific developmental processes and modeling neurodevelopmental disorders with disrupted thalamocortical communication at the molecular, cellular, and circuit levels. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/681772v1_ufig1.gif" ALT="Figure 1"> View larger version (61K): org.highwire.dtl.DTLVardef@95b599org.highwire.dtl.DTLVardef@c56085org.highwire.dtl.DTLVardef@43df08org.highwire.dtl.DTLVardef@1e7c4ed_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIhThCAs recapitulate the developmental sequence of reciprocal projections with synapses. C_LIO_LIhThCA cortical transcriptomes resemble the late fetal human cortex. C_LIO_LIThalamic paracrine signals promote progenitor expansion and cortical cytoarchitecture. C_LIO_LIWave-like activity originates in the thalamus and propagates across the cortex. C_LIO_LIThalamic input drives cell type-specific synchronization and circuit integration. C_LI

neuroscience↗

bioRxiv2025

MeCP2 controls dendritic morphogenesis via miR-199a-mediated Qki downregulation

Rett syndrome (RTT) (OMIM: 312750) is a severe neurodevelopmental disorder caused by mutations in the MECP2 gene. Although decreased dendritic morphogenesis has been observed in the brain of RTT patients and mouse models, the molecular mechanisms underlying these dendritic anomalies remain unclear. We have previously shown that MeCP2 facilitates specific microRNA (miRNA) processing by associating with the miRNA microprocessor Drosha complex. In this study, we show that MeCP2 positively regulates dendritic formation via miR-199a, a specific target of the MeCP2-Drosha complex. Overexpression of MeCP2 and miR-199a promotes dendritic development such as increases in dendrite length, branching number, and complexity. In contrast, blocking miR-199a inhibited dendrite formation and abolished enhanced dendritic development induced by MeCP2 expression. We also demonstrate that the decreased dendrite outgrowth observed in MeCP2-deficient neurons could be rescued by miR-199a expression. In addition, we found that miR-199a targets the 3 untranslated region of quaking (Qki), a negative regulator of dendritic development, and downregulates its protein expression level. Furthermore, we report an increase in the Qki protein expression level in miR-199a-2-deficient brains and show that Qki knockdown restores the dendritic morphology of miR-199a-2-Knockout (KO) neurons. Taken together, these results suggest that the MeCP2/miR-199a/Qki axis is critical for proper dendritic development and its dysregulation contributes to the dendritic pathology in RTT.

neuroscience↗

bioRxiv2025

Bridge protein-mediated viral targeting of cells expressing endogenous μ-opioid G protein-coupled receptors in the mouse and monkey brain

Targeting specific cell types is essential for understanding their functional roles in the brain. Although genetic approaches enable cell-type-specific targeting in animals, their application to higher mammalian species, such as nonhuman primates, remains challenging. Here, we developed a nontransgenic method using bridge proteins to direct viral vectors to cells endogenously expressing -opioid receptors (MORs), a G protein-coupled receptor. The bridge protein comprises the avian viral receptor TVB, the MOR ligand {beta}-endorphin ({beta}ed), and an interdomain linker. EnvB-enveloped viruses bind to the TVB component, followed by the interaction of {beta}ed with MORs, triggering viral infection in MOR-expressing cells. We optimized the secretion signals, domain configurations, and interdomain linkers of the bridge proteins to maximize viral targeting efficiency and specificity. Alternative configurations incorporating different ligands and viral receptors also induced viral infection in MOR-expressing cells. The optimized {beta}ed-f2-TVB bridge protein with EnvB-pseudotyped lentiviruses induced infection in MOR-expressing cells in the striatum of mice and monkeys. An intersectional approach combining {beta}ed-f2-TVB with a neuron-specific promoter refined cell-type specificity. This study establishes the foundation for the rational bridge protein design and the feasibility of targeting G protein-coupled receptors beyond tyrosine kinase receptors, thereby expanding targetable cell types in the brain and throughout the body. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/637063v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1fe91org.highwire.dtl.DTLVardef@effe51org.highwire.dtl.DTLVardef@217d73org.highwire.dtl.DTLVardef@b31251_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

Conversion of silent synapses to AMPA receptor-mediated functional synapses in human cortical organoids

Despite the crucial role of synaptic connections and neural activity in the development and organization of cortical circuits, the mechanisms underlying the formation of functional synaptic connections in the developing human cerebral cortex remain unclear. We investigated the development of -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-mediated synaptic transmission using human cortical organoids (hCOs) derived from induced pluripotent stem cells. Two-photon Ca2 imaging revealed an increase in the frequency and amplitude of spontaneous activity in hCOs on day 80 compared to day 50. Additionally, spontaneous neural activity in late-stage hCOs, but not in early-stage hCOs, was blocked by N-methyl-D-aspartate receptor (NMDAR) and AMPAR antagonists. However, transsynaptic circuit tracing with G-deleted rabies viral vectors indicated a similar number of synaptic connections in early- and late-stage hCOs. Notably, chemical labeling demonstrated a significant increase in AMPAR expression on the postsynaptic membrane and colocalization with NMDAR in late-stage hCOs. These results suggest that hCOs progressively organize excitatory synaptic transmission, concurrent with the transition from silent synapses lacking AMPARs to functional synapses containing NMDARs and AMPARs. This in vitro model of human cortical circuits derived from induced pluripotent stem cells reflects the developmental programs underlying physiological transitions, providing valuable insights into human corticogenesis and neurodevelopmental disorders. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=181 SRC="FIGDIR/small/629885v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@1432b6dorg.highwire.dtl.DTLVardef@d8350borg.highwire.dtl.DTLVardef@8273f8org.highwire.dtl.DTLVardef@8bbabd_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

Maternal progesterone and adipose mPRε in pregnancy regulate the embryonic nutritional state

Sex steroid hormones such as progesterone play a pivotal role in reproductive functions and maintaining pregnancy; however, the impact of progesterone on the interaction between mother and embryo is unclear. Here, we demonstrate that the relationship between maternal progesterone and membrane progesterone receptor epsilon (mPR{varepsilon}) in adipose tissue regulates embryonic nutritional environment and growth after birth in mice. The activation of adipose mPR{varepsilon} by increased progesterone during pregnancy enhanced maternal insulin resistance through the production of prostaglandins, thereby efficiently providing glucose to embryos. The offspring of mPR{varepsilon}-deficient mothers exhibited metabolic dysfunction, whereas mPR{varepsilon}-deficient mothers with high-fat-diet-induced obesity exhibited improved insulin sensitivity. These findings establish the importance of progesterone as a nutritional regulator between mother and embryo, and suggest that mPR{varepsilon} modulators could be developed to treat pregnant glycemic control disorders such as gestational diabetes mellitus, as well as metabolic syndrome in offspring. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/609823v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@1ecd968org.highwire.dtl.DTLVardef@b5492aorg.highwire.dtl.DTLVardef@1d692ecorg.highwire.dtl.DTLVardef@47de8a_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2024

Layer Va neurons, as major presynaptic partners of corticospinal neurons, play critical roles in skilled movements

Corticospinal neurons (CSNs) are located in the cortex and projecting into the spinal cord. The activation of CSNs, which is associated with skilled motor behaviors, induces the activation of interneurons in the spinal cord. Eventually, motor neuron activation is induced by corticospinal circuits to coordinate muscle activation. Therefore, elucidating how the activation of CSNs in the brain is regulated is necessary for understanding the roles of CSNs in skilled motor behaviors. However, the presynaptic partners of CSNs in the brain remain to be identified. Here, we performed transsynaptic rabies virus-mediated brain-wide mapping to identify presynaptic partners of CSNs (pre-CSNs). We found that pre-CSNs are located in all cortical layers, but major pre-CSNs are located in layer Va. A small population of pre-CSNs are also located outside the cortex, such as in the thalamus. Inactivation of layer Va neurons in Tlx3-Cre mice results in deficits in skilled reaching and grasping behaviors, suggesting that, similar to CSNs, layer Va neurons are critical for skilled movements. Finally, we examined whether the connectivity of CSNs is altered after spinal cord injury (SCI). We found that unlike connections between CNSs and postsynaptic neurons, connections between pre-CSNs and CSNs do not change after SCI.

neuroscience↗

bioRxiv2023

Asymmetric cortical projections to striatal direct and indirect pathways distinctly control actions

The striatal direct and indirect pathways constitute the core for basal ganglia function in action control. Although both striatal D1- and D2-spiny projection neurons (SPNs) receive excitatory inputs from the cerebral cortex, whether or not they share inputs from the same cortical neurons, and how pathway-specific corticostriatal projections control behavior remain largely unknown. Here using a G-deleted rabies system in mice, we found that more than two-thirds of excitatory inputs to D2-SPNs also target D1-SPNs, while only one-third do so vice versa. Optogenetic stimulation of striatal D1- vs. D2-SPN-projecting cortical neurons differently regulate locomotion, reinforcement learning and sequence behavior, implying the functional dichotomy of pathway-specific corticostriatal subcircuits. These results reveal the partially segregated yet asymmetrically overlapping cortical projections on striatal D1- vs. D2-SPNs, and that the pathway-specific corticostriatal subcircuits distinctly control behavior. It has important implications in a wide range of neurological and psychiatric diseases affecting cortico-basal ganglia circuitry. In BriefKlug, Yan et al. employed a modified rabies system in combination with slice physiology, optogenetics and behavioral tests to reveal that pathway-specific corticostriatal subcircuits distinctly control actions. HighlightsO_LIOne-third of the excitatory inputs to D1-SPNs project to D2-SPNs, while two-third of the excitatory inputs to D2-SPNs also target D1-SPNs C_LIO_LIActivation of D1-SPN projecting cortical neurons triggers behavioral effects in line with postsynaptic striatal direct pathway activation C_LIO_LIActivation of D2-SPN projecting cortical neurons causes behavioral effects similar with co-activation of both direct and indirect pathways C_LIO_LICorticostriatal subcircuits control actions in a brain-region and pathway-specific manner C_LI

neuroscience↗

bioRxiv2023

Modeling the marmoset brain using embryonic stem cell-derived cerebral assembloids

Studying the non-human primate (NHP) brain is required for the translation of rodent research to humans, but remains a challenge for molecular, cellular, and circuit-level analyses in the NHP brain due to the lack of in vitro NHP brain system. Here, we report an in vitro NHP cerebral model using marmoset (Callithrix jacchus) embryonic stem cell-derived cerebral assembloids (CAs) that recapitulate inhibitory neuron migration and cortical network activity. Cortical organoids (COs) and ganglionic eminence organoids (GEOs) were induced from cjESCs and fused to generate CAs. GEO cells expressing the inhibitory neuron marker LHX6 migrated toward the cortical side of CAs. COs developed their neural activity from a synchronized pattern to an unsynchronized pattern as COs matured. CAs showed mature neural activity with an unsynchronized pattern. The marmoset assembloid system will provide an in vitro platform for the NHP neurobiology and facilitate translation into humans in neuroscience research, regenerative medicine, and drug discovery.

neuroscience↗

bioRxiv2022

Posteromedial cortical networks encode visuomotor prediction errors.

Predicting future events based on internal models is essential for animal survival. Predictive coding postulates that errors between prediction and observation in lower-order areas update predictions in higher-order areas through the hierarchy. However, it is unclear how predictive coding is implemented in the hierarchy of the brain. Herein, we report the neural mechanism of the hierarchical processing and transmission of bottom-up prediction error signals in the mouse cortex. Ca2+ imaging and electrophysiological recording in virtual reality revealed responses to visuomotor mismatches in the retrosplenial, dorsal visual, and anterior cingulate cortex. These mismatch responses were attenuated when mismatches became predictable through experience. Optogenetic inhibition of bottom-up signals reduced a behavioral indicator for prediction errors. Moreover, cellular-level mismatch responses were modeled by Bayesian inference using a state-space model. This study demonstrates hierarchical circuit organization underlying prediction error propagation, advancing the understanding of predictive coding in sensory perception and learning in the brain. O_FIG O_LINKSMALLFIG WIDTH=188 HEIGHT=200 SRC="FIGDIR/small/504075v2_ufig1.gif" ALT="Figure 1"> View larger version (82K): org.highwire.dtl.DTLVardef@1f03960org.highwire.dtl.DTLVardef@46df08org.highwire.dtl.DTLVardef@dc97ccorg.highwire.dtl.DTLVardef@7200ae_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗