Biomedical subjects

Xing Sun

Publications and source records attributed to Xing Sun.

5 recordsLinked to original sources

PubMed2026

Full-length single-cell spatial transcriptomics reveals spatial and cell-type-specific transcript isoforms in the primate brain.

The primate brain exhibits complex RNA alternative splicing heterogeneity crucial for functional complexity, yet systematic spatial isoform characterization has been lacking. We developed Fullscope-seq, a full-length single-molecule large field-of-view spatial transcriptomics sequencing method at single-cell resolution, based on programmed concatenation cDNA for multiple long-read sequencing platforms. Applying Fullscope-seq to the macaque brain, we uncovered thousands of genes exhibiting differential transcript usage (DTU) across cortical layers, cell types and brain regions. Fullscope-seq resolved hundreds of major isoform switches across distinct brain regions and identified DTUs between superficial and deep cortical layers. Cortical layer-specific DTUs showed cell-composition dependence, whereas regional DTUs were regulated according to both cellular composition and spatial contexts. These isoform variations showed substantial enrichment for neuropsychiatric disorder-associated genes and were conserved across platforms and species. Our study establishes a scalable framework for spatial isoform analysis and provides a resource for understanding transcriptomic diversity in complex tissues.

Animals↗

PubMed2004

Biopurification of industrial waste gas from rubber regeneration.

By using the biopurifying technology, the organic waste gas in low concentrations emitted from the rubber-regeneration process was purified in this research. The result of the 100-day continuous running test of the industrial test device indicated that the purification efficiency of toluene in the rubber-regeneration waste gas could be maintained at about 90% for a long period of time and the treated waste gas could meet the China National Emission Standard. The cost of waste gas biotreatment was about 0.12-0.14% of rubber-regeneration production value of the factory. The biopurifying technology of waste gas displayed its excellent technical advancement and economic rationale. The following industrialized device was run continuously and passed the examination and acceptance by the local EPA.

Air Pollutants↗

PubMed2003

Diurnal pineal 3-O-sulphotransferase 2 expression controlled by beta-adrenergic repression.

The 3-O-sulfotransferases (3OSTs) catalyze the addition of sulfate groups at the 3-OH site of glucosamine in heparan sulfate proteoglycans, which serve as critical mediators of various biological functions. We demonstrate that the 3OST2 isoform is expressed at high levels in the rat pineal specifically during the daylight hours. The dramatic diurnal rhythm of 3OST2 is regulated by central clock-controlled activities of the superior cervical ganglion, persists in constant darkness, and is inducible by light at nighttime. Importantly, 3OST2 transcription is blocked by beta-adrenergic agonists that activate the pineal melatonin formation and is induced by beta-adrenergic antagonists, which block melatonin production in vivo. Because of the inverse expression and regulation patterns of 3OST2 with serotonin N-acetyltransferase, the enzyme controlling the melatonin rhythm in the pineal, we tested the effects of forced expression of 3OST2 in the night pineals on N-acetyltransferase gene expression and melatonin production and found that, surprisingly, 3OST2 expression at night fails to interfere with melatonin synthesis. These data suggest 3OST2 may serve a unique function in the pineal that may be independent of melatonin formation.

Animals↗

PubMed2003

Long-term in vivo pineal microdialysis.

This study describes the development of a new technique for long-term measurement of daily 5-hydroxytryptamine (5-HT) and melatonin contents in the pineal gland of freely moving rats. The technique features a number of novel improvements over previous protocols. It allows visualization of the pineal gland for accurate targeting of the guide cannula, which minimizes bleeding; incurs no direct injury to the surrounding brain tissues; and causes no interference with the sympathetic innervation from the superior cervical ganglia. Robust releases of melatonin and indole precursors were continuously monitored quantitatively and reproducibly for more than 2 wk in the same animal. In addition, effects of pharmacological agents on in vivo pineal circadian rhythms can be studied reproducibly over time, and gene expression profiles can be correlated with physiological consequences in single animals. Using these approaches, it is found that beta-adrenergic activation leads to decreased release of 5-HT, and that increased cAMP signaling in vivo results in activation of N-acetyltransferase gene induction and melatonin production. These studies will enhance the understanding of signaling pathways that regulate pineal 5-HT and melatonin synthesis and secretion.

Adrenergic beta-Agonists↗

PubMed2002

Circadian 5-HT production regulated by adrenergic signaling.

Using on-line microdialysis, we have characterized in vivo dynamics of pineal 5-hydroxytryptamine (5-HT; serotonin) release. Daily pineal 5-HT output is triphasic: (i) 5-HT levels are constant and high during the day; (ii) early in the night, there is a novel sharp rise in 5-HT synthesis and release, which precedes the nocturnal rise in melatonin synthesis; and (iii) late in the night, levels are low. This triphasic 5-HT production persists in constant darkness and is influenced strongly by intrusion of light at night. We demonstrate that both diurnal 5-HT synthesis and 5-HT release are activated by sympathetic innervation from the superior cervical ganglion and show that these processes are controlled by distinct receptors. The increase in 5-HT synthesis is controlled by beta-adrenergic receptors, whereas the increase in 5-HT release is mediated by alpha-adrenergic signaling. On the other hand, the marked decrease in 5-HT content and release late at night is a passive process, influenced by the extent of melatonin synthesis. In the absence of melatonin synthesis, the late-night decline in 5-HT release is prevented, reaching levels roughly twice as high as that of the day value. In summary, our results demonstrate that 5-HT levels display marked circadian rhythms that depend on adrenergic signaling.

Animals↗