Publications by authors named "Shota Tanifuji"

The effects of angiotensin II (AngII) on blood vessel development and remodeling have been extensively investigated in mice and humans. However, its action on the vessels in the zebrafish remains largely unknown. To investigate whether AngII affects vascular morphology in vivo, we administered AngII into the endothelial-specific transgenic reporter zebrafish (Tg[kdrl:EGFP]) at the 1-cell stage.

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  • The study aims to understand the role of the PGE2 receptor EP4 in vascular intimal hyperplasia (IH), noting its differing effects in vascular smooth muscle cells (VSMCs) and endothelial cells.
  • Researchers generated EP4 reporter mice and found that EP4 expression peaks in VSMCs two weeks post-femoral artery injury, affecting IH's progression based on EP4 levels in these cells.
  • The downstream effects of EP4 signaling in VSMCs were explored, revealing that EP4 promotes VSMC proliferation and migration through fibulin-1 and its interaction with ECM1, suggesting that targeting this signaling pathway could be a potential therapeutic approach to manage IH.
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The ductus arteriosus (DA) immediately starts closing after birth. This dynamic process involves DA-specific properties, including highly differentiated smooth muscle, sparse elastic fibers, and intimal thickening (IT). Although several studies have demonstrated DA-specific gene expressions using animal tissues and human fetuses, the transcriptional profiles of the closing DA and the patent DA remain largely unknown.

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SUMOylation is an important post-translational modification process involving covalent attachment of SUMO (Small Ubiquitin-like MOdifier) protein to target proteins. Here, we investigated the potential for SUMO-1 protein to modulate the function of the Ca2.2 (N-type) voltage-gated calcium channel (VGCC), a protein vital for presynaptic neurotransmitter release.

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Short-term synaptic depression (STD) is a common form of activity-dependent plasticity observed widely in the nervous system. Few molecular pathways that control STD have been described, but the active zone (AZ) release apparatus provides a possible link between neuronal activity and plasticity. Here, we show that an AZ cytomatrix protein CAST and an AZ-associated protein kinase SAD-B coordinately regulate STD by controlling reloading of the AZ with release-ready synaptic vesicles.

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  • Presynaptic nerve terminals must ensure stable neurotransmission by efficiently resupplying synaptic vesicles (SVs) despite changes in action potential (AP) frequency.
  • Myosins II and VI, two types of motor proteins, play key roles in this process by managing the dynamics of actin and transporting membranes in brain synapses.
  • Research shows that myosin VI supplies SVs slowly and consistently after APs, while myosin IIB responds quickly during high-frequency AP firing, highlighting their unique contributions to SV reuse pathways linked to different neuronal firing patterns.
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Synaptic vesicle glycoprotein (SV)2A is a transmembrane protein found in secretory vesicles and is critical for Ca(2+) -dependent exocytosis in central neurons, although its mechanism of action remains uncertain. Previous studies have proposed, variously, a role of SV2 in the maintenance and formation of the readily releasable pool (RRP) or in the regulation of Ca(2+) responsiveness of primed vesicles. Such previous studies have typically used genetic approaches to ablate SV2 levels; here, we used a strategy involving small interference RNA (siRNA) injection to knockdown solely presynaptic SV2A levels in rat superior cervical ganglion (SCG) neuron synapses.

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  • Calcium regulation is crucial for neurotransmitter release and synaptic transmission, but how Ca(2+) dynamics specifically influence synaptic vesicle release in sympathetic neurons is not well understood.* -
  • The study reveals that both fast and slow Ca(2+) signals at synaptic sites significantly impact cholinergic transmission, with slow signals also playing a role in synaptic responses during repetitive action potentials and recovery phases.* -
  • Results suggest that local Ca(2+) signals are organized into fast and slow temporal phases, which together facilitate exocytosis and short-term plasticity, ultimately supporting stable acetylcholine release over time.*
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  • Presynaptic nerve terminals need to recycle synaptic vesicles efficiently to maintain neurotransmission despite varying incoming action potentials (APs).
  • Researchers studied the role of three dynamin isoforms in vesicle trafficking and found that each isoform has unique response rates to different frequencies of neuronal activity.
  • Dynamin 3 acted quickly after APs, while dynamin 1 handled high-frequency recycling but with slower kinetics, and dynamin 2 showed a mixed response, highlighting the importance of these proteins in matching vesicle reuse with firing patterns.
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Mast cells play a key role in allergic inflammation by releasing various mediators, such as histamine, serotonin, leukotrienes and cytokines. A signaling cascade of events activated by stimulation with antigens contributes to the regulation of mast cell degranulation. While various anti-inflammatory and anti-allergic drugs have been developed that inhibit degranulation of mast cells, the inhibitory mechanism has been poorly understood.

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