Biomedical subjects

Xiao-Wei Zhou

Publications and source records attributed to Xiao-Wei Zhou.

5 recordsLinked to original sources

PubMed2006

[Construction, expression and preliminary pharmacokinetic analysis of IL-1ra mutants].

Interleukin-1 receptor antagonist (IL-1ra), a member of IL-1 family, is a naturally occurring IL-1 inhibitor as "receptor antagonist", which blocks biological responses mediated by IL-1. Recombinant human IL-1ra (rhIL-1ra, Kineret) was introduced in clinical trials involving patients with RA. Between 2001 to approximately 2002, rhIL-1 ra was approved by the US Food and Drug Administration and the European Agency for the Evaluation of Medicine Procedure. Unfortunately, 10,000 to 100,000-fold excess amounts of IL-1ra are needed to relieve disease because minimal IL-1 can induce complete biological responses, and the dosage of 100 to approximately 150mg/day in a RA patient is so big that it greatly influence patients' physical, psychological and economical situation. In this study, IL-1ra mutants were established by site-specific mutagenesis to improve its stability. The sites of mutagenesis included R6 K7-AA,R93 K94-AA and K97 R98-AA. IL-1ra and its mutants were expressed in E. coli BL21 (DE3) using pTIG-Trx expressing system with the induction of IPTG. The recombinant proteins were purified by Ni2+ chelate chromatography and Sephadex G75 gel filtration chromatography. The activity of mutants is as high as IL-1ra. We characterized the pharmacokinetic profile of IL-1ra and its mutants. The third mutant's half life is 2.26 times than wt IL-1ra. The study has provided some approaches and experience for further research to improve the metabolism stability of IL-1ra.

Animals↗

PubMed2006

[Expression, purification and activity analysis of anti-human transferrin receptor scFv].

Human transferrin receptor (TfR) was isolated from homogenates of placental tissues by affinity chromatography on transferrin-Sepharose, and then used to screen human scFv against it from a fully-synthesized phage scFv library. After verifying the specificity, gene fragment of one of the selected scFv was inserted into the plasmid pET22b(+) and transformed into E. coli BL21(DE3) . Expression of scFv in transformant was induced with 0.5mmol/L IPTG. ELISA assay on HeLa cells showed that scFv protein could recognize and bind to TfR on the surface of HeLa cells. The scFv was purified by one-step affinity chromatography with Ni+ -NTA agarose, and injected into Kunming mouse via tail veins. This scFv was detected in brain tissues 1h later by capillary depletion method, which indicates that scFv protein can permeate through the blood brain barrier by mediation of the TfR receptor. Our works lay the foundation for the treatment of tumors and central nervous system diseases.

Animals↗

PubMed2006

[Design and implementation of DB sequence optimization software].

TIR (Translation Initiation Region) efficiency is very important in prokaryotic expression. The TIR's efficiency is highly dependent on SD (Shine-Dalgarno) sequence, distance between SD sequence and start codon, DB (Downstream Box) sequence, TIR's second structure, codon adaptation and so on. In this paper, we designed and implemented the software to optimize DB sequence and 5' rare codons. It generated some optimization sequences by analyzing the target sequence and comparing it with 16S RNA. And the optimization sequences is sorting by number of base pairing, location of base pairing and codon adaptation. We drew up the algorithm and the core of code in this paper.

Base Sequence↗

PubMed2005

[Involvement of N-type calcium channels in pain and antinociception].

N-type voltage-dependent calcium channels are critical for pain transduction and modulation. These channels are highly present at the presynaptic terminals of nociceptive neurons in dorsal horn of the spinal cord where they regulate the release of the key pro-nociceptive neurotransmitters such as glutamate and substance P. Consistent with this, the selective blockers of the N-type channels are powerful analgesics, and, mice lacking the N-type Ca(v)2. 2 subunit have higher pain thresholds compared to wild-type. The N-type channels are also present at synapses in the autonomic system and the central nervous system, the inhibition of these synapses is the main reason of the side effects in analgesic therapy with current N-type channel blockers. Recently, a unique splice isoform of the N-type channels was found exclusively expressed at the nociceptive neurons in dorsal root ganglia, which may represent a novel target for pain management.

Animals↗

PubMed2002

[Construction of eukaryotic expression vector using neomycin-resistance gene mutant as selectable marker].

Neomycin-resistance gene is widely used as a selectable marker in eukaryotic expression vector. It codes neomycin phosphotransferase II (NPT II) which confers resistance to various aminoglycoside antibiotic such as G418 and kanamycine. In this work, by site-directed mutagenesis the neo gene mutant was obtained. The expression vector pmDNA using the neo gene mutant as selectable marker has been constructed. After inserting interest luciferase gene, the expression plasmid pmDNAluc + was stably transfected CHO-K1 cells. As a result, the expression positive ratio reaches to approximate 95% and the ratio of high expression colonies is apparently higher than the controls.

Amino Acid Sequence↗