Biomedical subjects

Zheng Xia

Publications and source records attributed to Zheng Xia.

5 recordsLinked to original sources

PubMed2025

OmicsTweezer: A distribution-independent cell deconvolution model for multi-omics Data.

Cell deconvolution estimates cell type proportions from bulk omics data, enabling insights into tissue microenvironments and disease. However, practical applications are often hindered by batch effects between bulk data and referenced single-cell data, a challenge that is frequently overlooked. To address this discrepancy, we developed OmicsTweezer, a distribution-independent cell deconvolution model. By integrating optimal transport with deep learning, OmicsTweezer aligns simulated and real data in a shared latent space, effectively mitigating data shifts and inter-omics distribution differences. OmicsTweezer is versatile, capable of deconvolving bulk RNA-seq, bulk proteomics, and spatial transcriptomics. Extensive evaluations on simulated and real-world datasets demonstrate its robustness and accuracy. Furthermore, applications in prostate and colon cancer showcase OmicsTweezer's ability to identify biologically meaningful cell types. As a unified deconvolution framework for multi-omics data, OmicsTweezer offers an efficient and powerful tool for studying disease microenvironments.

Humans↗

PubMed2006

Recombinant omega-conotoxin MVIIA possesses strong analgesic activity.

BACKGROUND: omega-Conotoxin (CTX) MVIIA is a specific antagonist of N-type voltage-sensitive calcium channels. A synthetic peptide version of CTX MVIIA (ziconotide) has been approved by the US FDA for severe and chronic pain. Given the high cost and complexity of the synthetic process of the disulfide-rich peptide, the genetic recombinant approach may simplify the development of this potent therapeutic agent. AIM: In this study, we report a new method for production of the recombinant CTX MVIIA. METHOD: A novel DNA fragment encoding CTX MVIIA was designed using Escherichia coli-preferred codons, and the fragment was cloned into the expression vector pGEX(2T). The fusion protein, CTX MVIIA and glutathione-S-transferase (GST) [GST-CTX MVIIA], was expressed in E. coli and purified by affinity chromatography on a glutathione-agarose column. After digestion with thrombin, the CTX MVIIA fragment was purified on a Sephacryl S-100 HR column and identified by mass spectrometry. The bioactivity of the peptide was evaluated by the hot tail-flick assay, in which the CTX MVIIA was intracerebroventricularly administered into Sprague-Dawley rats and its antinociceptive effect measured. RESULTS: The analgesic activity of the conotoxin was about 800 times stronger than that of morphine. CONCLUSION: The recombinant CTX MVIIA expressed in E. coli has shown marked analgesic activity, which may have potential in clinical application.

Analgesics↗

PubMed2005

[Cloning and expression of luffin-a gene from the seeds of Luffa cylindrical].

OBJECTIVE: To clone luffin-a cDNA from the seeds of Luffa cylindrical, and to obtain bioactive recombinant luffin-a protein using the expression vector pET-44a (+) in E. coli. METHODS: The cDNA sequence encoding luffin-a was cloned from the fresh seeds of Luffa cylindrical by RT-PCR. The target DNA fragments were sequenced after T-A cloning. The luffin-a expression plasmid was constructed by inserting the luffin-a cDNA fragment into vector pET-44a (+). Luffin-a was expressed in E. coli by addition of IPTG into final concentration 1.0 mmol/L. The recombinant luffin-a was identified by SDS-PAGE. The biological activity of luffin-a protein was evaluated by using the MTT assay in HepG2 cells following fluid-phase endocytosis. RESULTS: In comparison with the reported luffin-a, the homology of nucleotide sequence of the cloned luffin-a gene was 99.73%, while their amino acid sequences were identical. The solubility of recombinant protein was analyzed by SDS-PAGE, and the luffin-a was mainly produced in inclusion bodies. The recombinant luffin-a, renatured by dialysis of the denatured products, showed a similar cytotoxicity to ricin A chain. CONCLUSION: The cDNA of luffin-a has been successfully cloned. The recombinant luffin-a protein expressed by E. coli is bioactive.

Amino Acid Sequence↗

PubMed2003

A peptide mimetic of Gal-alpha 1,3-Gal is able to block human natural antibodies.

The carbohydrate of Gal-alpha1,3-Gal is thought to be the major antigenic epitope present on pig vascular endothelium. The peptides that mimic the binding of antigenic epitope (Gal-alpha1,3-Gal) to lectin BS-I-B4 were identified from screening a filamentous phage-displayed random library. A phage bearing the peptide NCVSPYWCEPLAPSARA has been identified to bind the lectin strongly. Melibiose was able to inhibit the binding of the human natural anti-alpha Gal antibody to the peptide competitively. Our experiments show that the peptide mimetic of Gal-alpha1,3-Gal is able to inhibit the agglutination of pig RBCs by human natural antibody or lectin BS-I-B4. The peptide inhibitor of human natural antibodies may prove useful in pig-to-human xenotransplantation.

Amino Acid Sequence↗

PubMed2002

Constitutive activity of signal transducer and activator of transcription 3 protein in acute myeloid leukemia blasts is associated with short disease-free survival.

Signal transducer and activator of transcription (STAT) proteins are involved in hematopoietic cytokine receptor signaling pathways that regulate cell proliferation, differentiation, and survival. STATs are dysregulated in acute myeloid leukemia (AML); mechanisms of dysregulation include constitutive activation and truncation of the C-terminal transactivation domain; the latter results in a beta isoform that has a trans-dominant negative effect on gene induction mediated by the full-length STAT alpha form. It was hypothesized that constitutive STAT activity might correlate with unfavorable treatment outcome in AML. Pretreatment bone marrow samples from 63 adult patients with AML were analyzed by electrophoretic mobility shift assay for the presence of STAT DNA-binding activity. Isoforms and relative levels of STAT proteins were determined by immunoblotting. Constitutive STAT3 activity was detected in samples from 28 (44%) patients. Pretreatment clinical characteristics, expression of STAT alpha/beta isoforms, and treatment regimens did not differ significantly between patients with and without constitutive STAT3 activity. Disease-free survival (DFS) was significantly shorter in patients with than in patients without constitutive STAT3 activity (median 8.7 vs 20.6 months; P =.01). Overall survival did not differ significantly. The subgroup of patients with constitutive STAT3 activity and the STAT3 beta isoform had the shortest DFS (P =.006) and shorter overall survival (P =.049) than all other patients. Whether adverse treatment outcome is attributable to constitutive STAT activity itself or to a process that leads to constitutive STAT activity remains to be determined. This is the first demonstration of a prognostic significance for STAT proteins in a malignancy.

Bone Marrow↗