Photocatalytic manipulation of Ca signaling for regulating cellular and animal behaviors via MOF-enabled HO generation.

The in situ generation of HO in cells in response to external stimulation has exceptional advantages in modulating intracellular Ca dynamics, including high controllability and biological safety, but has been rarely explored. Here, we develop photocatalyst-based metal-organic frameworks (DCSA-MOFs) to modulate Ca responses in cells, multicellular spheroids, and organs. By virtue of the efficient photocatalytic oxygen reduction to HO without sacrificial agents, photoexcited DCSA-MOFs can rapidly trigger Ca outflow from the endoplasmic reticulum with single-cell precision in a repeatable and controllable manner, enabling the propagation of intercellular Ca waves (ICW) over long distances in two-dimensional and three-dimensional cell cultures.

β-Catenin and SOX2 Interaction Regulate Visual Experience-Dependent Cell Homeostasis in the Developing Thalamus.

In the vertebrate brain, sensory experience plays a crucial role in shaping thalamocortical connections for visual processing. However, it is still not clear how visual experience influences tissue homeostasis and neurogenesis in the developing thalamus. Here, we reported that the majority of SOX2-positive cells in the thalamus are differentiated neurons that receive visual inputs as early as stage 47 .

Epigenetic regulation of GABAergic differentiation in the developing brain.

In the vertebrate brain, GABAergic cell development and neurotransmission are important for the establishment of neural circuits. Various intrinsic and extrinsic factors have been identified to affect GABAergic neurogenesis. However, little is known about the epigenetic control of GABAergic differentiation in the developing brain.

Cell landscape of larval and adult Xenopus laevis at single-cell resolution.

The rapid development of high-throughput single-cell RNA sequencing technology offers a good opportunity to dissect cell heterogeneity of animals. A large number of organism-wide single-cell atlases have been constructed for vertebrates such as Homo sapiens, Macaca fascicularis, Mus musculus and Danio rerio. However, an intermediate taxon that links mammals to vertebrates of more ancient origin is still lacking.

Development of advanced oil/water separation technologies to enhance the effectiveness of mechanical oil recovery operations at sea: Potential and challenges.

Mechanical oil recovery (i.e., booming and skimming) is the most common tool for oil spill response.

Evidence That -Mediated Intracellular Calcium Release in Oligodendrocytes Regulates the Development of Carbonic Anhydrase II + Type I/II Oligodendrocytes and the Sizes of Myelin Fibers.

Myelination of neuronal axons in the central nervous system (CNS) by oligodendrocytes (OLs) enables rapid saltatory conductance and axonal integrity, which are crucial for normal brain functioning. Previous studies suggested that different subtypes of oligodendrocytes in the CNS form different types of myelin determined by the diameter of axons in the unit. However, the molecular mechanisms underlying the developmental association of different types of oligodendrocytes with different fiber sizes remain elusive.

Electrophysiological Recording for Study of Retinotectal Circuitry.

The innervation of the optic tectum of by retinal ganglion cells controls visual information processing and behavioral output. Several indicators can be used to evaluate the functional inputs/outputs of tectal neurons, such as spontaneous activity, visually evoked currents, temporal receptive fields, and spatial receptive fields. Analysis of multiple functional properties in the same neurons allows increased understanding of mechanisms underlying visual system function and plasticity.

Xenopus in revealing developmental toxicity and modeling human diseases.

The Xenopus model offers many advantages for investigation of the molecular, cellular, and behavioral mechanisms underlying embryo development. Moreover, Xenopus oocytes and embryos have been extensively used to study developmental toxicity and human diseases in response to various environmental chemicals. This review first summarizes recent advances in using Xenopus as a vertebrate model to study distinct types of tissue/organ development following exposure to environmental toxicants, chemical reagents, and pharmaceutical drugs.

Wnt/β-Catenin Signaling in Neural Stem Cell Homeostasis and Neurological Diseases.

Neural stem/progenitor cells (NSCs) maintain the ability of self-renewal and differentiation and compose the complex nervous system. Wnt signaling is thought to control the balance of NSC proliferation and differentiation via the transcriptional coactivator β-catenin during brain development and adult tissue homeostasis. Disruption of Wnt signaling may result in developmental defects and neurological diseases.

d-Glucuronolactone attenuates para-xylene-induced defects in neuronal development and plasticity in Xenopus tectum in vivo.

Xylene and its derivatives are known to be neurotoxic to the central nervous system of animals. Our previous work has shown that para-xylene (PX) can cause an increase in apoptotic cells and abnormal avoidance behavior in Xenopus laevis. However, the mechanism underlying the impact of PX on neuronal structural and functional plasticity is less clear.

Excitatory synaptic dysfunction cell-autonomously decreases inhibitory inputs and disrupts structural and functional plasticity.

Functional circuit assembly is thought to require coordinated development of excitation and inhibition, but whether they are co-regulated cell-autonomously remains unclear. We investigate effects of decreased glutamatergic synaptic input on inhibitory synapses by expressing AMPAR subunit, GluA1 and GluA2, C-terminal peptides (GluA1CTP and GluA2CTP) in developing Xenopus tectal neurons. GluACTPs decrease excitatory synaptic inputs and cell-autonomously decreases inhibitory synaptic inputs in excitatory and inhibitory neurons.

Role of the visual experience-dependent nascent proteome in neuronal plasticity.

Experience-dependent synaptic plasticity refines brain circuits during development. To identify novel protein synthesis-dependent mechanisms contributing to experience-dependent plasticity, we conducted a quantitative proteomic screen of the nascent proteome in response to visual experience in optic tectum using bio-orthogonal metabolic labeling (BONCAT). We identified 83 differentially synthesized candidate plasticity proteins (CPPs).

Visual experience dependent regulation of neuronal structure and function by histone deacetylase 1 in developing Xenopus tectum in vivo.

Histone deacetylase 1 (HDAC1) is thought to play pivotal roles in neurogenesis and neurodegeneration. However, the role of HDAC1 in neuronal growth and structural plasticity in the developing brain in vivo remains unclear. Here, we show that in the optic tectum of Xenopus laevis, HDAC1 knockdown dramatically decreased the frequency of AMPAR-mediated synaptic currents and increased the frequency of GABAAR-mediated currents, whereas HDAC1 overexpression significantly decreased the frequency of GABAAR-mediated synaptic currents.

HDAC3 But not HDAC2 Mediates Visual Experience-Dependent Radial Glia Proliferation in the Developing Tectum.

Radial glial cells (RGs) are one of the important progenitor cells that can differentiate into neurons or glia to form functional neural circuits in the developing central nervous system (CNS). Histone deacetylases (HDACs) has been associated with visual activity dependent changes in BrdU-positive progenitor cells in the developing brain. We previously have shown that HDAC1 is involved in the experience-dependent proliferation of RGs.

Increased apoptosis and abnormal visual behavior by histone modifications with exposure to para-xylene in developing Xenopus.

Xylene and its derivatives are raw materials widely used in industry and known to be toxic to animals. However, the mechanism underlying the neurotoxicity of para-xylene (PX) to the central nervous system (CNS) in vivo is less clear. Here, we exposed Xenopus laevis tadpoles to sub-lethal concentrations of PX during the critical period of brain development to determine the effects of PX on Xenopus development and visual behavior.

Experience-Dependent Bimodal Plasticity of Inhibitory Neurons in Early Development.

Inhibitory neurons are heterogeneous in the mature brain. It is unclear when and how inhibitory neurons express distinct structural and functional profiles. Using in vivo time-lapse imaging of tectal neuron structure and visually evoked Ca(2+) responses in tadpoles, we found that inhibitory neurons cluster into two groups with opposite valence of plasticity after 4 hr of dark and visual stimulation.

Subcellular Localization of Class I Histone Deacetylases in the Developing Xenopus tectum.

Histone deacetylases (HDACs) are thought to localize in the nucleus to regulate gene transcription and play pivotal roles in neurogenesis, apoptosis, and plasticity. However, the subcellular distribution of class I HDACs in the developing brain remains unclear. Here, we show that HDAC1 and HDAC2 are located in both the mitochondria and the nucleus in the Xenopus laevis stage 34 tectum and are mainly restricted to the nucleus following further brain development.

HDAC1 regulates the proliferation of radial glial cells in the developing Xenopus tectum.

In the developing central nervous system (CNS), progenitor cells differentiate into progeny to form functional neural circuits. Radial glial cells (RGs) are a transient progenitor cell type that is present during neurogenesis. It is thought that a combination of neural trophic factors, neurotransmitters and electrical activity regulates the proliferation and differentiation of RGs.

Acute synthesis of CPEB is required for plasticity of visual avoidance behavior in Xenopus.

Neural plasticity requires protein synthesis, but the identity of newly synthesized proteins generated in response to plasticity-inducing stimuli remains unclear. We used in vivo bio-orthogonal noncanonical amino acid tagging (BONCAT) with the methionine analog azidohomoalanine (AHA) combined with the multidimensional protein identification technique (MudPIT) to identify proteins that are synthesized in the tadpole brain over 24 hr. We induced conditioning-dependent plasticity of visual avoidance behavior, which required N-methyl-D-aspartate (NMDA) and Ca(2+)-permeable α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, αCaMKII, and rapid protein synthesis.

Neurogenesis is required for behavioral recovery after injury in the visual system of Xenopus laevis.

Nonmammalian vertebrates have a remarkable capacity to regenerate brain tissue in response to central nervous system (CNS) injury. Nevertheless, it is not clear whether animals recover lost function after injury or whether injury-induced cell proliferation mediates recovery. We address these questions using the visual system and visually-guided behavior in Xenopus laevis tadpoles.

Inhibition to excitation ratio regulates visual system responses and behavior in vivo.

The balance of inhibitory to excitatory (I/E) synaptic inputs is thought to control information processing and behavioral output of the central nervous system. We sought to test the effects of the decreased or increased I/E ratio on visual circuit function and visually guided behavior in Xenopus tadpoles. We selectively decreased inhibitory synaptic transmission in optic tectal neurons by knocking down the γ2 subunit of the GABA(A) receptors (GABA(A)R) using antisense morpholino oligonucleotides or by expressing a peptide corresponding to an intracellular loop of the γ2 subunit, called ICL, which interferes with anchoring GABA(A)R at synapses.

Acute and gradual increases in BDNF concentration elicit distinct signaling and functions in neurons.

Extracellular factors may act on cells in two distinct modes: an acute increase in concentration as a result of regulated secretion, or a gradual increase in concentration when secreted constitutively or from a distant source. We found that cellular responses to brain-derived neurotrophic factor (BDNF) differed markedly depending on how BDNF was delivered. In cultured rat hippocampal neurons, acute and gradual increases in BDNF elicited transient and sustained activation of TrkB receptor and its downstream signaling, respectively, leading to differential expression of Homer1 and Arc.

Ca(2+) signaling evoked by activation of Na(+) channels and Na(+)/Ca(2+) exchangers is required for GABA-induced NG2 cell migration.

NG2 cells originate from various brain regions and migrate to their destinations during early development. These cells express voltage-gated Na(+) channels but fail to produce typical action potentials. The physiological role of Na(+) channels in these cells is unclear.

Type A GABA-receptor-dependent synaptic transmission sculpts dendritic arbor structure in Xenopus tadpoles in vivo.

The emergence of dendritic arbor structure in vivo depends on synaptic inputs. We tested whether inhibitory GABAergic synaptic transmission regulates Xenopus optic tectal cell dendritic arbor development in vivo by expressing a peptide corresponding to an intracellular loop (ICL) of the gamma2 subunit of type A GABA receptors (GABA(A)R), which is required to anchor GABA(A) receptors to the postsynaptic scaffold. Enhanced green fluorescent protein (EGFP)-tagged ICL (EGFP-ICL) was distributed in a punctate pattern at putative inhibitory synapses, identified by vesicular GABA transporter immunoreactive puncta.