How to Identify and Quantify Microplastics and Nanoplastics Using Raman Imaging?

How to Identify and Quantify Microplastics and Nanoplastics Using Raman Imaging

A Neuronal Culture System to Detect Prion Synaptotoxicity

<div><p>Synaptic pathology is an early feature of prion as well as other neurodegenerative diseases. Although the self-templating process by which prions propagate is well established, the mechanisms by which prions cause synaptotoxicity are poorly understood, due largely to the absence of experimentally tractable cell culture models. Here, we report that exposure of cultured hippocampal neurons to PrP^Sc, the infectious isoform of the prion protein, results in rapid retraction of dendritic spines. This effect is entirely dependent on expression of the cellular prion protein, PrP^C, by target neurons, and on the presence of a nine-amino acid, polybasic region at the N-terminus of the PrP^C molecule. Both protease-resistant and protease-sensitive forms of PrP^Sc cause dendritic loss. This system provides new insights into the mechanisms responsible for prion neurotoxicity, and it provides a platform for characterizing different pathogenic forms of PrP^Sc and testing potential therapeutic agents.</p></div

Computational Study of Rh-Catalyzed Carboacylation of Olefins: Ligand-Promoted Rhodacycle Isomerization Enables Regioselective C–C Bond Functionalization of Benzocyclobutenones

The mechanism, reactivity, regio- and enantioselectivity of the Rh-catalyzed carboacylation of benzocyclobutenones are investigated using density functional theory (DFT) calculations. The calculations indicate that the selective activation of the relatively unreactive C1–C2 bond in benzocyclobutenone is achieved via initial C1–C8 bond oxidative addition, followed by rhodacycle isomerization via decarbonylation and CO insertion. Analysis of different ligand steric parameters, ligand steric contour maps, and the computed activation barriers revealed the origin of the positive correlation between ligand bite angle and reactivity. The increase of reactivity with bulkier ligands is attributed to the release of ligand–substrate repulsions in the P–Rh–P plane during the rate-determining CO insertion step. The enantioselectivity in reactions with the (<i>R</i>)-SEGPHOS ligand is controlled by the steric repulsion between the C8 methylene group in the substrate and the equatorial phenyl group on the chiral ligand in the olefin migratory insertion step

sj-docx-1-pib-10.1177_09544054231201919 – Supplemental material for Fabrication of Ni-TiN nanocomposite coatings by ultrasonic assisted jet electrodeposition

Supplemental material, sj-docx-1-pib-10.1177_09544054231201919 for Fabrication of Ni-TiN nanocomposite coatings by ultrasonic assisted jet electrodeposition by Yuanlong Chen, Huigui Li, Jiachen Zhu, Cheng Fang, Zhongquan Li and Wei Jiang in Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture</p

The N-terminal domain of PrP^C is essential for PrP^Sc-induced dendritic spine loss.

<p>Hippocampal neurons from Tg(Δ23–111) mice (<b>A-D</b>) and Tg(Δ23–31) mice (<b>E-H</b>) (both on the <i>Prn-p</i>^0/0 background) were treated for 24 hr with 4.4 μg/ml of PrP^Sc purified without proteases (<b>B, F</b>), or with an equivalent amount of mock-purified material from uninfected brains (<b>A, E</b>). Neurons were then fixed and stained with Alexa 488-phalloidin. Scale bar in panel F = 20 μm (applicable to panels A, B, E). Pooled measurements of spine number (<b>C, G</b>) and area (<b>D, H</b>) were collected from 20–24 cells from 4 independent experiments. N.S., not significantly different by Student’s t-test.</p

PK-digested PrP^Sc causes dendritic spine loss.

<p>(<b>A</b>) Silver stain and Western blot (using anti-PrP antibody D18) of a PrP^Sc sample and a mock-purified control sample, after digestion with PK. Lane M, molecular size markers in kDa. Hippocampal neurons from wild-type (WT) mice (<b>B, C</b>) and PrP knockout (<i>Prn-p</i>^0/0) mice (<b>D, E</b>) were treated for 24 hr with 4.4 μg/ml of purified, PK-treated PrP^Sc (<b>C, E</b>), or with an equivalent amount of mock-purified sample (<b>B, D</b>). Neurons were then fixed and stained with Alexa 488-phalloidin. Scale bar in panel E = 20 μm (applicable to panels B-D). Pooled measurements of spine number (<b>F</b>) and area (<b>G</b>) were collected from 20–24 cells from 3 independent experiments. ***p<0.001 by Student’s t-test; N.S., not significantly different.</p

Purified PrP^Sc, prepared using pronase E, causes PrP^C-dependent spine loss.

<p>(<b>A</b>) Silver stain and Western blot analysis (using anti-PrP antibody IPC1) of PrP^Sc purified from scrapie-infected brains using pronase E, and mock-purified material from uninfected brains. Lane M, molecular size markers in kDa. Hippocampal neurons from wild-type (WT) mice (<b>B, C</b>) and PrP knockout (<i>Prn-p</i>^0/0) mice (<b>D, E</b>) were treated for 24 hr with 4.4 μg/ml of purified PrP^Sc (<b>C, E</b>), or with an equivalent amount of material mock-purified from uninfected brains (<b>B, D</b>). Neurons were then fixed and stained with Alexa 488-phalloidin. Scale bar in panel E = 20 μm (applicable to panels B-D). Pooled measurements of spine number (<b>F</b>) and area (<b>G</b>) were collected from 16–18 cells from 3 independent experiments. ***p<0.001 or *p<0.05 by Student’s t-test; N.S., not significantly different.</p

Purified PrP^Sc, prepared without proteases, causes PrP^C-dependent spine loss.

<p>(<b>A</b>) Silver stain and Western blot analysis (using anti-PrP antibody D18) of PrP^Sc purified from scrapie-infected brains without proteases, and mock-purified material from uninfected brains. Lane M, molecular size markers in kDa. Hippocampal neurons from wild-type (WT) mice (<b>B, C</b>) and PrP knockout (<i>Prn-p</i>^0/0) mice (<b>D, E</b>) were treated for 24 hr with 4.4 μg/ml of purified PrP^Sc (<b>C, E</b>), or with an equivalent amount of material mock-purified from uninfected brains (<b>B, D</b>). Neurons were then fixed and stained with Alexa 488-phalloidin. Scale bar in panel E = 20 μm (applicable to panels B-D). Pooled measurements of spine number (<b>F</b>) and area (<b>G</b>) were collected from 22–25 cells from 4 independent experiments. ***p<0.001 by Student’s t-test; N.S., not significantly different.</p

Table_1_Endothelial β-Catenin Deficiency Causes Blood-Brain Barrier Breakdown via Enhancing the Paracellular and Transcellular Permeability.DOCX

Disruption of the blood-brain barrier (BBB) causes or contributes to neuronal dysfunction and several central nervous system (CNS) disorders. Wnt/β-catenin signaling is essential for maintaining the integrity of the adult BBB in physiological and pathological conditions, including stroke. However, how the impairment of the endothelial Wnt/β-catenin signaling results in BBB breakdown remains unclear. Furthermore, the individual contributions of different BBB permeability-inducing mechanisms, including intercellular junction damage, endothelial transcytosis, and fenestration, remains unexplored. Here, we induced β-catenin endothelial-specific conditional knockout (ECKO) in adult mice and determined its impact on BBB permeability and the underlying mechanism. β-catenin ECKO reduced the levels of active β-catenin and the mRNA levels of Wnt target genes in mice, indicating downregulation of endothelial Wnt/β-catenin signaling. β-catenin ECKO mice displayed severe and widespread leakage of plasma IgG and albumin into the cerebral cortex, which was absent in wild-type controls. Mechanistically, both the paracellular and transcellular transport routes were disrupted in β-catenin ECKO mice. First, β-catenin ECKO reduced the tight junction protein levels and disrupted the intercellular junction ultrastructure in the brain endothelium. Second, β-catenin ECKO substantially increased the number of endothelial vesicles and caveolae-mediated transcytosis through downregulating Mfsd2a and upregulating caveolin-1 expression. Interestingly, fenestration and upregulated expression of the fenestration marker Plvap were not observed in β-catenin ECKO mice. Overall, our study reveals that endothelial Wnt/β-catenin signaling maintains adult BBB integrity via regulating the paracellular as well as transcellular permeability. These findings may have broad applications in understanding and treatment of CNS disorders involving BBB disruption.</p

ALDH^high-CD8+ T treatment prolongs the overall survival of the tumor-bearing mice.

<p>The mice treated with ALDH^high-CD8+ T cells survived much longer than the mice treated with PBS, H-CD8+ T, or ALDH^low-CD8+ T cells.</p