Biomedical subjects

Yibing Jia

Publications and source records attributed to Yibing Jia.

5 recordsLinked to original sources

PubMed2005

Leveraging human genomic information to identify nonhuman primate sequences for expression array development.

BACKGROUND: Nonhuman primates (NHPs) are essential for biomedical research due to their similarities to humans. The utility of NHPs will be greatly increased by the application of genomics-based approaches such as gene expression profiling. Sequence information from the 3' end of genes is the key resource needed to create oligonucleotide expression arrays. RESULTS: We have developed the algorithms and procedures necessary to quickly acquire sequence information from the 3' end of nonhuman primate orthologs of human genes. To accomplish this, we identified terminal exons of over 15,000 human genes by aligning mRNA sequences with genomic sequence. We found the mean length of complete last exons to be approximately 1,400 bp, significantly longer than previous estimates. We designed primers to amplify genomic DNA, which included at least 300 bp of the terminal exon. We cloned and sequenced the PCR products representing over 5,500 Macaca mulatta (rhesus monkey) orthologs of human genes. This sequence information has been used to select probes for rhesus gene expression profiling. We have also tested 10 sets of primers with genomic DNA from Macaca fascicularis (Cynomolgus monkey), Papio hamadryas (Baboon), and Chlorocebus aethiops (African green monkey, vervet). The results indicate that the primers developed for this study will be useful for acquiring sequence from the 3' end of genes for other nonhuman primate species. CONCLUSION: This study demonstrates that human genomic DNA sequence can be leveraged to obtain sequence from the 3' end of NHP orthologs and that this sequence can then be used to generate NHP oligonucleotide microarrays. Affymetrix and Agilent used sequences obtained with this approach in the design of their rhesus macaque oligonucleotide microarrays.

Algorithms↗

PubMed2005

Expression of lynx1 in developing lung and its modulation by prenatal nicotine exposure.

The expression of nicotinic acetylcholine receptors (nAChR) in fetal lung suggests maternal smoking during pregnancy effects newborn lung structure and function by the direct interaction of nicotine with nAChR in the developing lung. The recent identification of the lynx1 nAChR modulator protein in nicotinic neurons in the brain suggests that lynx1 may be similarly expressed in the lung. To study this, cDNAs encoding lynx1 were cloned from rhesus monkey lung. The temporal expression of lynx1 was studied in pre- and postnatal monkey lungs by in situ hybridization, immunohistochemistry, and realtime polymerase chain reaction (PCR). Lynx1 mRNA signal and lynx1 immunohistochemical staining were localized predominantly in airway epithelial cells, submucous glands, and smooth muscle cells, in endothelial and smooth muscle cells in vessel walls, and in alveolar type II cells. The distribution of lynx1 was similar to that of alpha4, beta2, and beta4 nAChR expression as determined by immunohistochemistry. Immunohistochemical staining also co-localized choline acetyltransferase, the enzyme that synthesizes acetylcholine, with lynx1 expression. Lynx1 expression was first observed in 71-day fetal lungs and increased with age. Immunohistochemistry, Western analysis, and realtime PCR analysis showed increased lynx1 expression in lungs following prenatal nicotine exposure. Thus, lynx1 is co-expressed with nAChR in the lung. Alteration of lynx1 levels is a potential new mechanism by which nicotine affects lung development.

Aging↗

PubMed2005

Vitamin C prevents the effects of prenatal nicotine on pulmonary function in newborn monkeys.

Smoking during pregnancy leads to decreased pulmonary function and increased respiratory illness in offspring. Our laboratory has previously demonstrated that many effects of smoking during pregnancy are mediated by nicotine. We now report that vitamin C supplementation can prevent some of the effects of maternal nicotine exposure on pulmonary function of offspring. Timed-pregnant rhesus monkeys were treated with 2 mg/kg/day nicotine bitartrate from Gestation Days 26 to 160. On Gestation Day 160 (term, 165 days) fetuses were delivered by C-section and subjected to pulmonary function testing the following day. Nicotine exposure significantly reduced forced expiratory flows, but supplementation of mothers with 250 mg vitamin C per day prevented the effects of nicotine on expiratory flows. Vitamin C supplementation also prevented the nicotine-induced increases in surfactant apoprotein-B protein. Neither nicotine nor nicotine plus vitamin C significantly affected levels of cortisol or cytokines, which have been shown to affect lung development and surfactant expression. Prenatal nicotine exposure significantly decreased levels of elastin content in the lungs of offspring, and these effects were slightly attenuated by vitamin C. These findings suggest that vitamin C supplementation may potentially be clinically useful to limit the deleterious effects of maternal smoking during pregnancy on offspring's lung function.

Animals↗

PubMed2004

Acetylcholine is an autocrine or paracrine hormone synthesized and secreted by airway bronchial epithelial cells.

The role of acetylcholine (ACh) as a key neurotransmitter in the central and peripheral nervous system is well established. However, the role of ACh may be broader because ACh may also function as an autocrine or paracrine signaling molecule in a variety of nonneuronal tissues. To begin to establish ACh of nonneuronal origin as a paracrine hormone in lung, we have examined neonatal and adult monkey bronchial epithelium for the components involved in nicotinic cholinergic signaling. Using immunohistochemistry and RT-PCR, we have demonstrated in lung bronchial epithelial cells (BECs) expression of choline acetyltransferase, the vesicular ACh transporter, the choline high-affinity transporter, alpha7, alpha4, and beta2 nicotinic ACh receptor (nAChR) subunits, and the nAChR accessory protein lynx1. Confocal microscopy demonstrates that these factors are expressed in epithelial cells and are clearly distinct from neighboring nerve fibers. Confirmation of RNA identity has been confirmed by partial sequence analysis of PCR products and by cDNA cloning. Primary culture of BECs confirms the synthesis and secretion of ACh and the activity of cholinesterases. Thus, ACh meets all the criteria for an autocrine/paracrine hormone in lung bronchial epithelium. The nonneuronal cholinergic signaling pathway in lung provides a potentially important target for cholinergic drugs. This pathway may also explain some of the effects of nicotine on fetal development and also provides additional mechanisms by which smoking affects lung cancer growth and development.

Acetylcholine↗

PubMed2003

Acetylcholine is synthesized by and acts as an autocrine growth factor for small cell lung carcinoma.

It is well established that small cell lung carcinomas (SCLCs) express receptors for acetylcholine (ACh) and that stimulation of these receptors by nicotine or other cholinergic agonists stimulates cell growth via activation of nicotinic cholinergic receptors (nAChRs) and/or muscarinic cholinergic receptors (mAChRs). The aim of this study was to determine whether SCLC cells synthesize and secrete ACh and respond to endogenous ACh to create a functioning cholinergic autocrine loop. Reverse transcription-PCR was used to screen a panel of SCLC cell lines for components of cholinergic signaling. Choline acetyltransferase (ChAT) and the vesicular ACh transporter (VAChT), as well as alpha3, alpha5, alpha7, beta2, and beta4, nAChR subunits and M3 and M5 mAChRs, were found to be present in most of the SCLC cell lines tested. Real-time PCR showed that mRNA levels for ChAT, VAChT, and alpha7 and beta2 nAChR subunits varied significantly among different SCLC cell lines tested. The H82 cell line was found to express the highest levels of ChAT, and that cell line was chosen for additional studies of ACh release and cell proliferation. ACh was easily detectable in H82 cell culture media, and levels of ACh were increased by the acetylcholinesterase inhibitor neostigmine. Vesamicol, an inhibitor of VAChT, and hemicholinium-3, an inhibitor of choline transport, both reduced H82 cell ACh basal release in a dose-dependent manner. In parallel with the reductions of ACh release, vesamicol and hemicholinium-3 also decreased H82 cell proliferation. H82 cell proliferation was also inhibited by the muscarinic and nicotinic antagonists atropine and mecamylamine, respectively, in dose- and time-dependent manners. Finally, archival cases of SCLC were screened by immunohistochemistry for expression of ChAT. Thirteen of 26 tumors screened were positive for ChAT. These findings demonstrate that SCLC can synthesize, secrete, and degrade ACh and that released ACh stimulates SCLC cell growth. Identification of this new autocrine loop provides a potential new target for therapeutic intervention.

Acetylcholine↗