Biomedical subjects

Dapeng Zhou

Publications and source records attributed to Dapeng Zhou.

13 recordsLinked to original sources

PubMed2025

Proteomic hub proteins CDKN2B, TRAPPC2L, WFS1, and ARPP19 drive biochemical recurrence and metastatic progression in prostate cancer: Protein macromolecule action.

The biological characteristics and metastasis mechanism of prostate cancer are complex, involving the important role of many proteins in cell transcriptional regulation. This study focused on the role of the proteomic hub proteins CDKN2B, TRAPPC2L, WFS1 and ARPP19 in the biochemical recurrence and metastasis progression of prostate cancer. Cross-platform transcriptome integration and differential expression analysis were used to evaluate transcriptome characteristics in a prostate cancer cohort. Functional enrichment analysis was performed by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation, and weighted gene co-expression network analysis (WGCNA) was used to investigate cancer progression subtypes. It was found that prostate cancer progression showed significant transcriptome heterogeneity, and low-expression genes dominated. We reveal the important role of epithelial-immune interactions and inflammatory signaling in transcriptional remodeling in prostate cancer. The co-expression network topology analysis showed that the immune-metabolic center module plays a central role in cancer progression. CDKN2B was identified as a key transcriptional determinant in prostate cancer typing, while TRAPPC2L and WFS1 acted as core transcriptional regulators, driving metastatic heterogeneity. ARPP19 and LOC650152 also show important transcriptional driving effects in advanced prostate cancer.

Humans↗

PubMed2006

Thio-isoglobotrihexosylceramide, an agonist for activating invariant natural killer T cells.

Thio-isoglobotrihexosylceramide (S-iGb3) might be resistant to alpha-galactosidases in antigen-presenting cells and have a longer retaining time in the lysosome before being loaded to CD1d. The biological assay showed that S-iGb3 demonstrates a much higher increase as a stimulatory ligand toward invariant natural killer T (iNKT) cells as compared to iGb3. [structure: see text].

Animals↗

PubMed2006

Cutting edge: impaired glycosphingolipid trafficking and NKT cell development in mice lacking Niemann-Pick type C1 protein.

Niemann-Pick type C1 (NPC1) is a late endosomal/lysosomal transmembrane protein involved in the cellular transport of glycosphingolipids and cholesterol that is mutated in a majority of patients with Niemann-Pick C neurodegenerative disease. We found that NPC1-deficient mice lacked Valpha14-Jalpha18 NKT cells, a major population of CD1d-restricted T cells that is conserved in humans. NPC1-deficient mice also exhibited marked defects in the presentation of Sphingomonas cell wall Ags to NKT cells and in bacterial clearance in vivo. A synthetic fluorescent alpha-glycosylceramide analog of the Sphingomonas Ag trafficked to the lysosome of wild-type cells but accumulated in the late endosome of NPC1-deficient cells. These findings reveal a blockade of lipid trafficking between endosome and lysosome as a consequence of NPC1 deficiency and suggest a common mechanism for the defects in lipid presentation and development of Valpha14-Jalpha18 NKT cells.

Animals↗

PubMed2006

A modified alpha-galactosyl ceramide for staining and stimulating natural killer T cells.

CD1d presentation of alpha-galactosyl ceramides to natural killer T cells has been a focal point of the study of regulatory T cells. KRN7000, an alpha-galactosyl ceramide originally generated from structure activity studies of antitumor properties of marine sponge glycolipids, is currently the most commonly used agonist ligand and is used to stain NKT cells. However, this glycolipid suffers from poor solubility and availability. We have developed an alpha-galactosyl ceramide with improved solubility over KRN7000 that effectively stains NKT cells, both mouse and human, and stimulates cytokine release at low concentrations.

Adjuvants, Immunologic↗

PubMed2006

The immunological function of iGb3.

The mechanistic studies on immune recognition of carbohydrates have been paved by the synergized advances in identifying the precise sugar structures recognized by the immune system, in analyzing the cellular and humoral components bearing the receptors for glycoconjugates, and production of the biological relevant carbohydrate epitopes by synthetic chemistry. In our current studies on natural antigenic glycolipids, we have found that the activation as well as the development of natural killer T cells (NKT) is guided by the information provided by glycolipid metabolism pathways in antigen presenting cells (APC). Based on genetic data and cellular immunological assays, we propose a neutral glycosphingolipid isoglobotrihexosylceramide, iGb3, as one of the candidates recognized by NKT cells under patho-physiological conditions such as cancer and auto-immune disease. New immunotherapy approaches might be explored by interfering with glycolipid metabolism or by directly supplementing rationally designed glycolipids.

Amino Acid Sequence↗

PubMed2006

[Effects of a hemostatic jelly with polylactic acid on hemostasis of injured cancellous bone].

OBJECTIVE: To prepare a self-made compound, hemostatic jelly with polylactic acid (PLA), which has the hemostatic and absorbable effect on injured cancellous bone. METHODS: Two bone defects of 5 mm in diameter and 4 mm in depth were subjected on 20 health rabbits by drilling through their either outside plate of the iliac, and were filled with hemostatic jelly(group A), bone wax(group B) and blank(group C) respectively. Hemostasis were observed and recorded after 1 and 10 minutes. Five specimens were harvested at 2, 4, 8 and 12 weeks postoperatively for histological observation. RESULTS: (1) Hemostatic effect: Bleeding of injured spongy bone stopped within 10 minutes after the treatment of hemostatic jelly and bone wax, but bleeding of blank did not stop. Hemostatic jelly and bone wax adhered to bone defects firmly within 10 minutes was after the treatment. (2) Absorbable effect: Hemostatic jelly and bone defects have not changed visibly in the first 2 weeks. With histological observation 4 to 8 weeks after the operation, hemostatic jelly was absorbed gradually and replaced by osteogeneous tissue. It was absorbed completely after 8 to 12 weeks. Bone wax was not absorbed after 12 weeks, no new bone tissue was observed at bone wax area. The blank was replaced by connective tissue and osteogeneous tissue partially after 12 weeks. CONCLUSION: The compound hemostatic jelly manifests both hemostatic and absorbable effects on injured cancellous bone and may substitute for bone wax in clinical application.

Animals↗

PubMed2005

Structure and function of a potent agonist for the semi-invariant natural killer T cell receptor.

Natural killer T cells express a conserved, semi-invariant alphabeta T cell receptor that has specificity for self glycosphingolipids and microbial cell wall alpha-glycuronosylceramide antigens presented by CD1d molecules. Here we report the crystal structure of CD1d in complex with a short-chain synthetic variant of alpha-galactosylceramide at a resolution of 2.2 A. This structure elucidates the basis for the high specificity of these microbial ligands and explains the restriction of the alpha-linkage as a unique pathogen-specific pattern-recognition motif. Comparison of the binding of altered lipid ligands to CD1d and T cell receptors suggested that the differential T helper type 1-like and T helper type 2-like properties of natural killer T cells may originate largely from differences in their 'loading' in different cell types and hence in their tissue distribution in vivo.

Amino Acid Motifs↗

PubMed2005

Exogenous and endogenous glycolipid antigens activate NKT cells during microbial infections.

CD1d-restricted natural killer T (NKT) cells are innate-like lymphocytes that express a conserved T-cell receptor and contribute to host defence against various microbial pathogens. However, their target lipid antigens have remained elusive. Here we report evidence for microbial, antigen-specific activation of NKT cells against Gram-negative, lipopolysaccharide (LPS)-negative alpha-Proteobacteria such as Ehrlichia muris and Sphingomonas capsulata. We have identified glycosylceramides from the cell wall of Sphingomonas that serve as direct targets for mouse and human NKT cells, controlling both septic shock reaction and bacterial clearance in infected mice. In contrast, Gram-negative, LPS-positive Salmonella typhimurium activates NKT cells through the recognition of an endogenous lysosomal glycosphingolipid, iGb3, presented by LPS-activated dendritic cells. These findings identify two novel antigenic targets of NKT cells in antimicrobial defence, and show that glycosylceramides are an alternative to LPS for innate recognition of the Gram-negative, LPS-negative bacterial cell wall.

Animals↗

PubMed2004

Lysosomal glycosphingolipid recognition by NKT cells.

NKT cells represent a distinct lineage of T cells that coexpress a conserved alphabeta T cell receptor (TCR) and natural killer (NK) receptors. Although the TCR of NKT cells is characteristically autoreactive to CD1d, a lipid-presenting molecule, endogenous ligands for these cells have not been identified. We show that a lysosomal glycosphingolipid of previously unknown function, isoglobotrihexosylceramide (iGb3), is recognized both by mouse and human NKT cells. Impaired generation of lysosomal iGb3 in mice lacking beta-hexosaminidase b results in severe NKT cell deficiency, suggesting that this lipid also mediates development of NKT cells in the mouse. We suggest that expression of iGb3 in peripheral tissues may be involved in controlling NKT cell responses to infections and malignancy and in autoimmunity.

Animals↗

PubMed2004

Effects of lipid chain lengths in alpha-galactosylceramides on cytokine release by natural killer T cells.

Glycolipid presentation by CD1 proteins has emerged as an important aspect of antigen recognition, and presentation of alpha-glycosylceramides by CD1d to natural killer T cells has become a central focus in understanding how glycolipid presentation can influence immune responses. An alpha-galactosylceramide containing relatively long lipid chains has been the subject of intense study because, when presented by CD1d to natural killer T cells, it stimulates the release of both proinflammatory and immunomodulatory cytokines. Using an efficient synthesis of alpha-galactosylceramides, we have prepared a series of glycolipids in which the lipid chain lengths have been incrementally varied. The responses of natural killer T cells to these glycolipids have been determined, and we have found that truncation of the phytosphingosine lipid chain increases the relative amounts of immunomodulatory cytokines released. In similar fashion, the length of the acyl chain in alpha-galactosylceramides influences cytokine release profiles.

Animals↗

PubMed2003

Editing of CD1d-bound lipid antigens by endosomal lipid transfer proteins.

It is now established that CD1 molecules present lipid antigens to T cells, although it is not clear how the exchange of lipids between membrane compartments and the CD1 binding groove is assisted. We report that mice deficient in prosaposin, the precursor to a family of endosomal lipid transfer proteins (LTP), exhibit specific defects in CD1d-mediated antigen presentation and lack Valpha14 NKT cells. In vitro, saposins extracted monomeric lipids from membranes and from CD1, thereby promoting the loading as well as the editing of lipids on CD1. Transient complexes between CD1, lipid, and LTP suggested a "tug-of-war" model in which lipid exchange between CD1 and LTP is on the basis of their respective affinities for lipids. LTPs constitute a previously unknown link between lipid metabolism and immunity and are likely to exert a profound influence on the repertoire of self, tumor, and microbial lipid antigens.

Animals↗

PubMed2003

Why are glycoproteins modified by poly-N-acetyllactosamine glyco-conjugates?

Poly-N-acetyllactosamine structures occur in mammalian glycoproteins in both N- and O-linked glycans. They represent a backbone for additional modifications by fucosyltransferases, sialyltransferases and sulfotransferases. These glycans have been suggested to be involved in biospecific interactions with selectins and other glycan-binding proteins. Moreover, the poly-N-acetyllactosamine chains in N-glycans have been found to promote tumor progression and metastasis. Poly-N-acetyllactosamine chains are synthesized by repeated alternating additions of N-acetylglucosamine and galactose, catalyzed by beta-1,3-N-acetylglucosaminyltransferases (poly-N-acetyllactosamine synthase) and beta-1,4-galactosyltransferases. This review describes the poly-N-acetyllactosamine assembling machinery and focuses on recent advances in the molecular cloning and characterization of poly-N-acetyllactosamine synthase gene families. Recent progress in revealing the biological functions of poly-N-acetyllactosamine structures by various approaches in vitro and in vivo using different model systems has also been summarized.

Animals↗

PubMed2002

The Drosophila melanogaster brainiac protein is a glycolipid-specific beta 1,3N-acetylglucosaminyltransferase.

Mutations at the Drosophila melanogaster brainiac locus lead to defective formation of the follicular epithelium during oogenesis and to neural hyperplasia. The brainiac gene encodes a type II transmembrane protein structurally similar to mammalian beta1,3-glycosyltransferases. We have cloned the brainiac gene from D. melanogaster genomic DNA and expressed it as a FLAG-tagged recombinant protein in Sf9 insect cells. Glycosyltransferase assays showed that brainiac is capable of transferring N-acetylglucosamine (GlcNAc) to beta-linked mannose (Man), with a marked preference for the disaccharide Man(beta1,4)Glc, the core of arthro-series glycolipids. The activity of brainiac toward arthro-series glycolipids was confirmed by showing that the enzyme efficiently utilized glycolipids from insects as acceptors whereas it did not with glycolipids from mammalian cells. Methylation analysis of the brainiac reaction product revealed a beta1,3 linkage between GlcNAc and Man, proving that brainiac is a beta1,3GlcNAc-transferase. Human beta1,3GlcNAc-transferases structurally related to brainiac were unable to transfer GlcNAc to Man(beta1,4)Glc-based acceptor substrates and failed to rescue a homozygous lethal brainiac allele, indicating that these proteins are paralogous and not orthologous to brainiac.

Acetylglucosamine↗