Biomedical subjects

Ling-Jia Qian

Publications and source records attributed to Ling-Jia Qian.

5 recordsLinked to original sources

PubMed2004

[Negative regulation of homocysteine metabolism by stress in rats].

To investigate the effect of stress on homocysteine metabolism in the rat and explore the mechanism as well as the key regulatory link of stress-induced hyperhomocysteinemia, male Wistar rats were treated with restraint stress while control rats received routine treatment. By HPLC-fluorometry, the homocysteine level in rat plasma was determined. Cystathionine beta-synthase (CBS) activity in blood, heart, liver and kidney was measured by radioisotope assay using [(14)C]-serine as the labeled substrate. Total RNA was isolated from rat liver after restraint stress. RT-PCR and Northern blot were used to estimate the level of CBS mRNA. The results showed that hyperhomocysteinemia was induced by restraint stress. The highest CBS enzyme activity was seen in rat livers. A decrease in hepatic activities of CBS was found in restraint stress rats. The 29.4% +/-2.5% reduction in the activity of CBS was accompanied by a 44.1% +/-3.4% decrease in its mRNA level. CBS enzyme activity was slightly elevated in the kidney of stressed rats while it was almost undeterminable in the cardiovascular system. The study suggests that stress leads to an inhibition of the transsulfuration pathway in homocysteine metabolism. The hepatic CBS influenced by stress at the level of transcription exerts a profound effect on the circulating levels of homocysteine. The liver is the key organ where stress affects homocysteine metabolism.

Animals↗

PubMed2004

Proteomic analysis of mitochondrial proteins in cardiomyocytes from chronic stressed rat.

Chronic restraint stress induces cardiac dysfunction as well as cardiomyocyte injury including severe ultrastructural alteration and cell death, but its mechanism and molecular basis remain unclear. Mitochondria play a key role in regulating cell life. For exploring mitochondrial proteins which correlate with stress-induced injury, two-dimensional electrophoresis and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) were applied. After comparing the protein profiles of myocardial mitochondria between a chronic restraint stress group and a control group, 11 protein spots were found altered, seven of which were identified by MALDI-TOF MS. Among the seven proteins, five proteins involved in the Krebs cycle and lipid metabolism in mitochondria decreased after chronic restraint stress. They were identified as carnitine palmitoyltransferase 2, mitochondrial acyl-CoA thioesterase 1, isocitrate dehydrogenase 3 (NAD+) alpha, fumarate hydratase 1 and pyruvate dehydrogenase beta. The last two proteins, creatine kinase and prohibitin, increased after chronic restraint stress. Biochemical tests for energy metabolism in mitochondria also supported the proteomic results. These findings provide clues for understanding the mechanism of dysfunction or injury in cardiomyocytes induced by chronic stress.

Animals↗

PubMed2004

Prokaryotic expression, polyclonal antibody preparation, and sub-cellular localization analysis of Na+, K+-ATPase beta2 subunit.

Na+, K+-ATPase beta2 subunit (NKA1b2) is not only a regulator of Na+, K+-ATPase, but also functions in the interaction between neuron and glia cells as a Ca2+-dependent adhesion molecule. To further study the function of NKA1b2, the anti-NKA1b2 polyclonal antibody was prepared to recognize the outer-membrane carboxyl portion segment of NKA1b2. The coding region for amino acids 190-290 at the carboxyl portion of NKA1b2 (NKA1b2-CP) was sub-cloned into the vector pGEX-4T-2 and introduced into the Escherichia coli BL21(DE3) cell for efficient soluble expression. The amino acid sequence of expressed protein was determined using mass spectrometry following Mascot analysis. After purification, GST-NKA-beta2-CP was used to immunize the adult rabbits following standard protocols. The produced antiserum could detect the NKA1b2 protein expressed not only in the prokaryotic cells (E. coli) but also in the eukaryotic cells (COS7) transfected with NKA1b2 expression vector (pEGFP-NKA1b2). Furthermore, the antiserum was used for determining the localization of NKA1b2 in primary culture of neonatal rat neurons using immunohistochemical technique. Results demonstrated that NKA1b2 was localized both in the cytoplasm and cellular membrane. The preparation of anti-NKA-beta2-CP polyclonal antibody will facilitate further functional study on NKA1b2.

Amino Acid Sequence↗

PubMed2003

[Differentially expressed genes associated with cold acclimation].

To investigate the upregulated genes associated with cold acclimation, a cold acclimation model was established based on Balb/C mouse. mRNA of muscle and liver were isolated, and the upregulated genes of these tissues were studied by representational differential analysis (RDA). The upregulated genes then were sequenced and searched by Blast software in GenBank database. The results showed that some genes were upregulated and possibly associated with cold acclimation. Three of these genes, transferrin, fibrinogen B-beta-chains and a new gene fragment (Genbank ID: AF454762), were confirmed to be upregulated by RNA slot-blot analysis. The finding of these genes might contribute to further understanding of the molecular mechanisms of cold acclimation.

Acclimatization↗

PubMed2003

[Identification of interaction and interaction domains between neuroglobin and Na(+), K(+)-ATPase beta2 subunit].

The pre-transformed human fetal brain cDNA library was used to screen the protein interacting with neuroglobin by using yeast two hybrid system III from ClonTech Inc. The protein encoded by one of the clones interacting with neuroglobin (NGB) was confirmed to be the C terminus of the Na(+), K(+)-ATPase beta2 subunit (NKA1b2) based on amino acid sequences. Then the full-length coding region cDNA sequence of NKA1b2 was obtained from human fetal brain cDNA library by PCR. A set of experiments were designed to test the interaction between NGB and NKA1b2. Interaction between NGB and NKA1b2 was confirmed by binding assay in vitro. Furthermore, the interaction was also proved by co-immunoprecipitation test in vivo. Moreover, the structure integrity of neuroglobin was found to be essential for the interaction between NGB and NKA1b2 by yeast two hybrid method with a series of neuroglobin truncated mutants.

Amino Acid Sequence↗