TRPM7 in Synaptic Vesicle Endocytosis and Comparison Between Inhibitory and Excitatory Neurons

Neurons in the brain communicate with each other by signaling molecules called neurotransmitters that are released into the synaptic cleft through synaptic vesicle (SV) exocytosis triggered by an action potential firing. The released neurotransmitter will then bind to the postsynaptic receptors to either activate or inhibit postsynaptic neurons. On the other side, newly formed SVs by endocytosis, after refilled with neurotransmitters, will replenish the readily releasable vesicle pool. Therefore, SV endocytosis is essential to maintain synaptic transmission, during high-frequency stimulations particularly. Upon openings of voltage-gated calcium channels (VGCCs) during AP firings, influx of Ca2+, by binding to synaptotagmins (the Ca2+ sensors for exocytosis), triggers vesicle fusion with the plasma membrane. Meanwhile, it has been shown that Ca2+ is also important in regulating endocytic kinetics of SVs, in addition to exocytosis. However, in contrast to VGCCs as the well-established Ca2+ influx pathway for exocytosis, the identity of the Ca2+ influx pathway for endocytosis remains ambiguous. In the present study, by taking advantage of electrophysiology and live-cell imaging assays, data from my experimental work lead me to propose that a Ca2+-permeable non-selective cation channel TPRM7, a TRP superfamily member, may serve as the Ca2+ influx pathway for SV endocytosis and thus regulate the endocytic kinetics of SVs in neurons. Glutamatergic and GABAergic neurons are the major excitatory and inhibitory neurons in the cerebral cortex, respectively. Studies of the postsynaptic properties of both classes of neurons have been extensively investigated using electrophysiology by taking advantage of the electric responses upon neurotransmitter binding to the postsynaptic receptors. In addition, a growing number of research studies focuses on differences of presynaptic properties in both types of neurons by using electrophysiology and live-cell imaging. However, many critical aspects of SV recycling between excitatory and inhibitory neurons remain to be elucidated. In the current work, using pHluorin-based live-cell imaging assays, we identified that the kinetics of SV exocytosis and endocytosis are different between excitatory and inhibitory neurons. Our work may thus provide important insights to understand the distinct functions of these two types of neurons in the brain

PyFluor: A Low-Cost, Stable, and Selective Deoxyfluorination Reagent

We report an inexpensive, thermally stable deoxyfluorination reagent that fluorinates a broad range of alcohols without substantial formation of elimination side products. This combination of selectivity, safety, and economic viability enables deoxyfluorination on preparatory scale. We employ the [¹⁸F]-labeled reagent in the first example of a no-carrier-added deoxy-radio­fluorination

Differentially expressed keratins and keratin-associated proteins in OSCC versus adjacent normal oral tissues.

<p>Differentially expressed keratins and keratin-associated proteins in OSCC versus adjacent normal oral tissues.</p

Overexpression of Lipocalins and Pro-Inflammatory Chemokines and Altered Methylation of PTGS2 and APC2 in Oral Squamous Cell Carcinomas Induced in Rats by 4-Nitroquinoline-1-Oxide

<div><p>Oral squamous cell carcinomas (OSCC) induced in F344 rats by 4-nitroquinoline-1-oxide (4-NQO) demonstrate considerable phenotypic similarity to human oral cancers. Gene expression studies (microarray and PCR) were coupled with methylation analysis of selected genes to identify molecular markers of carcinogenesis in this model and potential biochemical and molecular targets for oral cancer chemoprevention. Microarray analysis of 11 pairs of OSCC and site-matched phenotypically normal oral tissues from 4-NQO-treated rats identified more than 3500 differentially expressed genes; 1735 genes were up-regulated in rat OSCC versus non-malignant tissues, while 1803 genes were down-regulated. In addition to several genes involved in normal digestion, genes demonstrating the largest fold increases in expression in 4-NQO-induced OSCC include three lipocalins (VEGP1, VEGP2, LCN2) and three chemokines (CCL, CXCL2, CXCL3); both classes are potentially druggable targets for oral cancer chemoprevention and/or therapy. Down-regulated genes in 4-NQO-induced OSCC include numerous keratins and keratin-associated proteins, suggesting that alterations in keratin expression profiles may provide a useful biomarker of oral cancer in F344 rats treated with 4-NQO. Confirming and extending our previous results, PTGS2 (cyclooxygenase-2) and several cyclooxygenase-related genes were significantly up-regulated in 4-NQO-induced oral cancers; up-regulation of PTGS2 was associated with promoter hypomethylation. Rat OSCC also demonstrated increased methylation of the first exon of APC2; the increased methylation was correlated with down-regulation of this tumor suppressor gene. Overexpression of pro-inflammatory chemokines, hypomethylation of PTGS2, and hypermethylation of APC2 may be causally linked to the etiology of oral cancer in this model.</p></div

Genes demonstrating the greatest up-regulation in OSCC versus adjacent normal oral tissues.

<p>Gene expression data are derived from raw intensity values normalized to the 75th percentile of each array, followed by calculation of mean expression in paired OSCC and phenotypically normal oral tissues; n = 11 tissue pairs). P values were calculated by paired Student’s t-test using GeneSpring software</p><p>Genes demonstrating the greatest up-regulation in OSCC versus adjacent normal oral tissues.</p

Histology of normal and neoplastic oral (tongue) epithelium in F344 rats treated with 4-NQO.

<p>A. Phenotypically normal oral epithelium in F344 rat treated with 4-NQO (H&E, x100). B. Non-invasive squamous cell papilloma (Score 0) induced by 4-NQO. The tumor is confined to the mucosal epithelium of the tongue (H&E, x40). C. Invasive OSCC (Score +1) induced by 4-NQO. The cancer extends through the mucosal epithelial basement membrane into the lamina propria (H&E, x100). D. Invasive OSCC (Score +2) induced by 4-NQO. The cancer extends into the upper muscle layers of the tongue (H&E, x100). E. Invasive OSCC (Score +3) induced by 4-NQO. The cancer demonstrates extensive invasion into the underlying muscle layers of the tongue (H&E, x40).</p

Comparative expression of chemokine ligands and receptors in OSCC and adjacent normal oral tissues.

<p>Comparative expression of chemokine ligands and receptors in OSCC and adjacent normal oral tissues.</p

Additional file 1 of Study of myopia progression and risk factors in Hubei children aged 7–10 years using machine learning: a longitudinal cohort

Supplementary Material

Genes demonstrating the greatest down-regulation in OSCC versus adjacent normal oral tissues.

<p>Genes demonstrating the greatest down-regulation in OSCC versus adjacent normal oral tissues.</p

Methylation status of the proximal promoter of PTGS2 in OSCC versus adjacent normal oral tissues.

<p>*p < 0.05 in comparison to corresponding normal tissue</p><p>Methylation status of the proximal promoter of PTGS2 in OSCC versus adjacent normal oral tissues.</p