Biomedical subjects

Hao Wu

Publications and source records attributed to Hao Wu.

At least 19 recordsLinked to original sources

PubMed2026

Loss of Ku70 promotes mononucleate conidiation and homologous recombination in Phanerochaete chrysosporium.

Lignin is a major constituent of lignocellulose and the most abundant aromatic biopolymer on earth. It provides plants with rigidity and protection, but its recalcitrant nature also presents a significant barrier to lignocellulose valorization. The white-rot fungus Phanerochaete chrysosporium is among nature's most efficient lignin degraders, and its ligninolytic capabilities have been subjected to intensive investigations. Genome editing with precision is crucial for elucidating the in vivo mechanisms of its ligninolytic actions, but genetic manipulations of P. chrysosporium are often plagued by imprecision. This technical nuisance is driven primarily by canonical non-homologous end joining (c-NHEJ), a DNA repair system that requires little homology and depends on the binding of the Ku70/Ku80 heterodimer to double-strand break (DSB) ends. Loss of Ku70 or Ku80 abolishes c-NHEJ and significantly improves genome editing precision in many filamentous fungi, but it has yet to be examined and exploited in P. chrysosporium. Here, we constructed a homozygous ku70Δ mutant in a meiotic homokaryon of clear genetic background. Loss of Ku70 minimally impacts growth but significantly increases homologous recombination frequency from ~2% to ~66%, with ~32% of the latter being homozygous. Unexpectedly, loss of Ku70 also promotes mononucleate conidiation, which may facilitate isolation of homozygous mutants. Taken together, our work provides a valuable genetic tool to understand and exploit P. chrysosporium's remarkable ligninolytic capabilities.IMPORTANCEGenome editing with precision is essential to unraveling the intricacies of P. chrysosporium's exceptional ligninolytic capabilities, but the available tools are generally imprecise due to the dominance of non-homologous recombination, a problem that is further exacerbated by the discontinuation of Novozyme 234. We tackle these challenges by reestablishing protoplast-based transformation with Lywallzyme as an alternative. Importantly, we demonstrate that inactivation of c-NHEJ by deleting ku70 significantly increases gene knockout efficiency and report the unexpected involvement of c-NHEJ in regulating the number of nuclei during conidiation. Our work paves the way for future ventures into understanding ligninolysis in P. chrysosporium and building superior chassis for industrial applications.

Ku70↗

PubMed2026

Functional chimeric mRNAs encode proteins in mammalian immunity.

Individual mammalian mRNAs and proteins are typically believed to originate from single genomic loci, with isoform diversity arising through cis-splicing of pre-mRNA. Whether mRNA from distant genes can undergo trans-splicing to generate functionally relevant chimeric transcripts has remained unclear. Here we develop a pipeline combining long-read direct RNA sequencing with non-targeted and targeted validation to identify chimeric transcripts in macrophages. Chromatin conformation capture studies reveal that inflammation induces interchromosomal DNA interactions, positioning parent genes proximally to facilitate the formation of chimeric mRNA. Notably, we identify a protein-coding chimeric mRNA representing a fusion between the pore-forming protein gasdermin D (GSDMD)1,2 and a C-terminal domain translated out of frame from Tmem106a (Gsdmd-Tmem106a) in mice. We show that inflammasome priming upregulates Gsdmd-Tmem106a, with the protein localizing to the plasma membrane. After activation of the inflammasome, GSDMD-TMEM106A directly interacts with canonical GSDMD N termini to accelerate and enhance pore formation and IL-1β release. Finally, we show that GSDMD-TMEM106A balances host defence and immunopathology in vivo: its loss protects against lethal sepsis but compromises antibacterial defence, whereas overexpression enhances host protection while increasing sepsis lethality. We establish that protein-coding chimeric mRNAs formed by regulated transcript fusion events are operative during inflammation and immunity.

Journal Article↗

PubMed2026

Spatial mapping of RNA turnover kinetics in the mouse brain.

Gene regulation requires coordinated control of RNA synthesis and degradation, yet measuring RNA turnover across intact tissues remains challenging. Here we present spatial NT-seq, a method that combines transgenesis-free metabolic RNA labeling with in situ chemical recoding on spatial transcriptomics platforms to co-map newly synthesized and pre-existing RNAs. Applying spatial NT-seq to the mouse brain reveals pronounced regional heterogeneity in RNA turnover and identifies the dentate gyrus as a spatial hotspot marked by coordinated upregulation of basal RNA synthesis and decay. Moreover, spatial NT-seq uncovers rapid, brain region-specific transcriptional and post-transcriptional responses to electroconvulsive stimulation, a clinically relevant treatment for refractory depression. Finally, we leverage computational modeling to identify sequence features and post-transcriptional regulators that shape transcriptome-wide mRNA stability across spatial and cellular contexts in the mouse brain. Together, this integrated 'in vivo timescope' framework provides a spatially resolved view of RNA turnover kinetics and reveals the regulatory architecture of RNA stability in vivo.

Journal Article↗

PubMed2026

Phytolacca acinosa Roxb. induces intestinal toxicity through the histamine-MLCK-tight junction axis: Integrated evidence from proteomics, metabolomics, intestinal organoids and epithelial barrier validation.

Phytolacca acinosa Roxb. (PR) is a saponin-rich medicinal plant associated with gastrointestinal toxicity, but the mechanisms underlying PR-induced intestinal barrier injury remain unclear. In this study, raw PR extract was analytically characterized by UPLC-ZenoTOF-MS/MS, confirming triterpenoid saponins as the predominant constituents. C57BL/6 J mice were orally exposed to characterized PR extract (1.20 or 12.0 g/kg for 5 h), and Caco-2 cells and mouse intestinal organoids were used to assess epithelial toxicity and barrier disruption. Histopathology, ELISA, FITC-dextran permeability assays, immunofluorescence, CCK-8, LDH release, western blotting, DIA-based proteomics and untargeted metabolomics were integrated to define toxicological mechanisms. PR induced dose-dependent intestinal inflammation and barrier dysfunction, with the ileum as the most sensitive target. PR increased serum DAO and D-lactate and intestinal TNF-α and IL-1β, disrupted organoid morphology, enhanced epithelial permeability, and reduced ZO-1 expression. Proteomics revealed changes in inflammatory, lipid-metabolic, cytoskeletal and tight-junction pathways, including upregulation of MLCK3 and phospholipase-related proteins and downregulation of ZO-1 and ZO-2. Metabolomics identified histidine metabolism disturbance and histamine accumulation. Integrated multi-omics and pharmacological validation indicated that histamine activated the PLC/IP₃/Ca²⁺/CaM/MLCK cascade, promoting MLC phosphorylation, tight-junction disassembly and epithelial leakiness. MLCK inhibition partially restored ZO-1/ZO-2 expression and attenuated PR-induced epithelial injury. These findings identify the histamine-MLCK-tight junction axis as a key mechanism of PR-induced intestinal toxicity and support hazard identification of saponin-rich PR exposure.

Animals↗

PubMed2026

Genomic analysis of regulatory mechanisms governing EPS66A biosynthesis in Streptomyces changanensis HL-66.

Streptomyces changanensis HL-66 produces the α-(1,4)/(1,6)-glucan exopolysaccharide EPS66A, a potent plant immune elicitor with promising applications in plant protection. However, its low native fermentation yield limits large-scale application. To investigate the biosynthetic potential and regulatory mechanisms underlying EPS66A production, the whole genome of HL-66 was sequenced and analyzed. The HL-66 genome is 6.82 Mb in size, with a GC content of 74%, and encodes 6081 predicted functional genes. Among these, 1390 genes were annotated to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, 4187 were assigned to Gene Ontology (GO) terms, and 143 were classified into Clusters of Orthologous Groups (COG) categories. antiSMASH analysis identified 22 secondary metabolite biosynthetic gene clusters, including multiple polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) clusters. Functional analyses revealed that the glycosyltransferase gene (GTy) and the global regulatory gene (bldD) are involved in EPS66A biosynthesis. bldD is involved in morphological development and EPS66A production, whereas GTy specifically regulates EPS66A production without affecting growth or development. In both in vivo and potted-plant experiments, EPS66A (200 μg/mL) significantly reduced the severity of tobacco mosaic virus, apple anthracnose leaf spot, walnut bacterial leaf spot, and jujube anthracnose, achieving control efficacies of 90.21%, 87.95%, 77.41%, and 68.55%, respectively, and outperforming a commercial chitosan oligosaccharide control. These findings provide new insights into the genetic architecture and regulatory mechanisms of EPS66A biosynthesis and support its development as a polysaccharide-based green pesticide.

Streptomyces↗

PubMed2026

A genome-wide cross-trait analysis characterizes the shared genetic architecture between rheumatoid arthritis and psychiatric disorders.

OBJECTIVES: Patients with RA have a 2- to 3-fold elevated risk of psychiatric disorders, suggesting an underlying genetic link between these phenotypes. However, the shared genetic architectures and pathological mechanisms driving RA-psychiatric disorder comorbidity remain to be fully elucidated. Herein, we performed cross-trait analysis to investigate the shared genetic architecture between RA and psychiatric disorders. METHODS: Leveraging European-ancestry genome-wide association studies (GWASs) datasets of RA (n = 1 026 690) and 10 major psychiatric disorders (n = 14 307-1 222 882), we performed cross-trait pleiotropic analysis to identify the shared pleiotropic loci and genes between RA and psychiatric disorders, followed by functional annotation and Mendelian randomization analysis to explore the pathological mechanisms underlying RA-psychiatric disorder comorbidity. RESULTS: Our analysis revealed significant positive genetic correlations between RA and seven psychiatric disorders, such as major depressive disorder. From these correlations, we identified 61 pleiotropic loci jointly influencing RA and psychiatric disorder risk, along with 208 pleiotropic genes predominantly involved in immune and inflammatory response biological processes. Druggable target exploration identified 21 drug-gene interactions involving pleiotropic genes, with two genes (RHOA and TRAF3) classified in the clinically actionable category, representing potential therapeutic targets for both RA and psychiatric disorders. Mendelian randomization further demonstrated a bidirectional causal relationship between RA and schizophrenia, while supporting the causal roles of attention-deficit/hyperactivity disorder, major depressive disorder and post-traumatic stress disorder in increasing RA risk. CONCLUSION: Our findings elucidate the shared genetic architecture between RA and psychiatric disorders, providing novel insights into the pathological mechanisms underlying their comorbidity and laying the groundwork for improved comorbidity management.

Arthritis, Rheumatoid↗

PubMed2025

SIGEL: a context-aware genomic representation learning framework for spatial genomics analysis.

Spatial transcriptomics (ST) integrates spatial information into genomics, yet methods for generating spatially-informed gene representations are limited and computationally intensive. We present SIGEL, a cost-effective framework that derives gene manifolds from ST data by exploiting spatial genomic context. The resulting SIGEL-generated gene representations (SGRs) are context-aware, biologically meaningful, and robust across samples, making them highly effective for key downstream tasks, including imputing missing genes, detecting spatial expression patterns, identifying disease-related genes and interactions, and improving spatial clustering. Extensive experiments across diverse ST datasets validate SIGEL's effectiveness and highlight its potential in advancing spatial genomics research.

Genomics↗

PubMed2025

Accurate prediction of toxicity peptide and its function using multi-view tensor learning and latent semantic learning framework.

MOTIVATION: Therapeutic peptide is an important ingredient in the treatment of various diseases and drug discovery. The toxicity of peptides is one of the major challenges in peptide drug therapy. With the abundance of therapeutic peptides generated in the post-genomics era, it is a challenge to promptly identify toxicity peptides using computational methods. Although several efforts have been made, few algorithms are designed to identify whether a query peptide exhibits toxicity. Considering the varied levels of biological activities, the toxicity peptides should be further classified into multi-functional peptides. RESULTS: This study introduces a two-level predictor, ToxPre-2L, developed using the multi-view tensor learning and latent semantic learning framework. The proposed method utilized multi-label learning with feature induced labels to avoid the redundancy of information from each view. Then the multi-view tensor learning was employed to establish the latent semantic information among different views, while low-rank constraint learning was leveraged to exploit the correlation information among multi-labels. Finally, we constructed an updated toxicity peptide benchmark dataset to assess the effectiveness of the proposed method. Experimental results demonstrated that ToxPre-2L achieves a better performance than alternative computational methods in the prediction of toxicity peptides and their multi-functional types. AVAILABILITY AND IMPLEMENTATION: The source code and data of ToxPre-2L can be accessed at http://bliulab.net/ToxPre-2L.

Peptides↗

PubMed2007

The death domain superfamily in intracellular signaling of apoptosis and inflammation.

The death domain (DD) superfamily comprising the death domain (DD) subfamily, the death effector domain (DED) subfamily, the caspase recruitment domain (CARD) subfamily, and the pyrin domain (PYD) subfamily is one of the largest domain superfamilies. By mediating homotypic interactions within each domain subfamily, these proteins play important roles in the assembly and activation of apoptotic and inflammatory complexes. In this chapter, we review the molecular complexes assembled by these proteins, the structural and biochemical features of these domains, and the molecular interactions mediated by them. By analyzing the potential molecular basis for the function of these domains, we hope to provide a comprehensive understanding of the function, structure, interaction, and evolution of this important family of domains.

Animals↗

PubMed2006

Requirement of TORC1 for late-phase long-term potentiation in the hippocampus.

Late-phase long-term potentiation (L-LTP) and long-term memory depend on the transcription of mRNA of CRE-driven genes and synthesis of proteins. However, how synaptic signals propagate to the nucleus is unclear. Here we report that the CREB coactivator TORC1 (transducer of regulated CREB activity 1) undergoes neuronal activity-induced translocation from the cytoplasm to the nucleus, a process required for CRE-dependent gene expression and L-LTP. Overexpressing a dominant-negative form of TORC1 or down-regulating TORC1 expression prevented activity-dependent transcription of CREB target genes in cultured hippocampal neurons, while overexpressing a wild-type form of TORC1 facilitated basal and activity-induced transcription of CREB target genes. Furthermore, overexpressing the dominant-negative form of TORC1 suppressed the maintenance of L-LTP without affecting early-phase LTP, while overexpressing the wild-type form of TORC1 facilitated the induction of L-LTP in hippocampal slices. Our results indicate that TORC1 is essential for CRE-driven gene expression and maintenance of long-term synaptic potentiation.

Active Transport, Cell Nucleus↗

PubMed2006

TAK1-dependent signaling requires functional interaction with TAB2/TAB3.

Transforming growth factor beta-activated kinase 1 (TAK1), a member of the MAPKKK family, was initially described to play an essential role in the transforming growth factor beta-signaling pathway, but recent evidence has emerged implicating TAK1 in the interleukin (IL)-1 and tumor necrosis factor (TNF) pathways. Notably, two homologous proteins, TAB2 and TAB3, have been identified as adaptors linking TAK1 to the upstream adaptors TRAFs. However, it remains unclear whether the interaction between TAB2/TAB3 and TAK1 is necessary for its kinase activation and subsequent activation of the IKK and MAPK pathways. Here, we characterized the TAB2/TAB3-binding domain in TAK1 and further examined the requirement of this interaction for IL-1, TNF, and RANKL signaling. Through deletion mapping experiments, we demonstrated that the binding motif for TAB2/TAB3 is a non-contiguous region located within the last C-terminal 100 residues of TAK1. However, residues 479-553 of TAK1 appear to be necessary and sufficient for TAB2/TAB3 interaction. Conversely, residues 574-693 of TAB2 were shown to interact with TAK1. A green fluorescent protein fusion protein containing the last 100 residues of TAK1 (TAK1-C100) abolished the interaction of endogenous TAB2/TAB3 with TAK1, the phosphorylation of TAK1, and prevented the activation of IKK and MAPK induced by IL-1, TNF, and RANKL. Furthermore, TAK1-C100 blocked RANKL-induced nuclear accumulation of NFATc1 and consequently osteoclast differentiation consistent with the ability of a catalytically inactive TAK1 to block RANKL-mediated signaling. Significantly, our study provides evidence that the TAB2/TAB3 interaction with TAK1 is crucial for the activation of signaling cascades mediated by IL-1, TNF, and RANKL.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Phenotypic resistance of resistant strains of HIV type-1 subtype B in China.

BACKGROUND: This study was aim to explore the characteristics of phenotypic resistance of resistant strains of HIV type-1 (HIV-1) subtype B and to compare the concordance between the phenotypic resistance and genotypic resistance. METHODS: The genotypic resistance assay for the HIV-1 clinical isolates was performed. One isolate without resistance mutation was chosen as a drug-sensitive reference strain and seven subtype B isolates with resistance mutations were phenotypically tested. Fifty percent inhibitory concentrations (IC50) between resistant and sensitive viruses were compared. The resistance extent was determined by the folds of the increased IC50. The concordance between the phenotypic resistance and genotypic resistance was also analyzed. RESULTS: IC50 of resistant isolates were 0.0006 - 0.1300 micromol/L for zidovudine (AZT), 0.0016 - 0.0390 micromol/L for lamivudine (3TC), 0.0104 - 0.4234 micromol/L for nevirapine (NVP), and 0.0163 - 0.1142 micromol/L for indinavir (IDV), respectively. Genotypic and phenotypic resistance assays indicated that the resistant strains were intermediately and highly resistant to nucleotide analog reverse transcriptase inhibitors and non-nucleotide analog reverse transcriptase inhibitors. The phenotypic assay was consistent with the genotypic assay. For measuring the potential resistance, the genotypic assay was more sensitive than the phenotypic. In evaluating the resistance to protease inhibitors, these two assays were discrepant. CONCLUSIONS: Both the phenotypic and genotypic assays indicate that the resistant viruses exist in HIV-infected patients in China who have received treatment. Phenotypic and genotypic assays have high concordance, and the genotypic assay could replace the phenotypic assay to predict the HIV-1 resistance.

Anti-Retroviral Agents↗

PubMed2006

Site-specific Lys-63-linked tumor necrosis factor receptor-associated factor 6 auto-ubiquitination is a critical determinant of I kappa B kinase activation.

Tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) is a key mediator in proximal signaling of the interleukin-1/Toll-like receptor and the TNF receptor superfamily. Analysis of TRAF6-deficient mice revealed a fundamental role of TRAF6 in osteoclastogenesis; however, the molecular mechanism underlying TRAF6 signaling in this biological process is not understood. Recent biochemical evidence has indicated that TRAF6 possesses ubiquitin ligase activity that controls the activation of IKK and NF-kappaB. Because these studies are primarily based on cell-free systems, the role of the ubiquitin ligase activity of TRAF6 and its auto-ubiquitination to initiate the NF-kappaB pathway in vivo remain elusive. Here we show that an intact RING domain of TRAF6 in conjunction with the E2 enzyme Ubc13/Uev1A is necessary for Lys-63-linked auto-ubiquitination of TRAF6 and for its ability to activate IKK and NF-kappaB. Furthermore, a RING mutant of TRAF6 abolishes its ability to induce receptor activator of NF-kappaB-independent osteoclast differentiation and nuclear accumulation of the transcription factor NFATc1. Notably, we map the auto-ubiquitination site of TRAF6 to a single Lys residue, which if mutated renders TRAF6 unable to activate transforming growth factor-beta-activated kinase 1 and IKK and to cause spontaneous osteoclast differentiation. Additionally, we provide biochemical and in vivo evidence that TRAF6 serves as an E3 to directly ubiquitinate NEMO. Reconstituting TRAF6-deficent cells with various TRAF6 mutants, we clearly demonstrate the requirement for the TRAF6 RING domain and site-specific auto-ubiquitination of TRAF6 to activate IKK in response to interleukin-1. These data establish a signaling cascade in which regulated site-specific Lys-63-linked TRAF6 auto-ubiquitination is the critical upstream mediator of IKK.

Animals↗

PubMed2006

[The efficacy of early intervention for infants and toddlers with hearing loss].

OBJECTIVE: To investigate the efficacy of early intervention on language, pronunciation and cognitive developments of infants and toddlers with hearing loss and to build up an early intervention model. METHODS: Fifty-six children with moderate to profound sensorineural hearing loss aged 10 months to 2 years were divided into two groups. 20 children, aged 10 months to 2 years, received early intervention services after wearing hearing aids for 6 - 18 months, and 36 children, aged 11 months to 2 years, didn't receive any intervention. The type and degree of hearing loss were measured by a series of auditory tests. Language and cognitive developments of the children with hearing loss and 28 age, and sex-matched children with normal hearing, aged 10 to 23 months, were evaluated by the Gesell developmental schedules. The results were expressed as developmental quotient (DQ). Pronunciation test in mandarin Chinese was adopted to evaluate the speech development of the 56 children with hearing loss. RESULTS: (1) The language DQ according the Gesell developmental schedules of the children with hearing loss who received early intervention was (92.25 +/- 17.32), significantly higher than those children with hearing loss who didn't receive intervention (70.44 +/- 29.99, P = 0.00), whish was significantly lower than that of the normal hearing children (P = 0.00). However, there was no significant difference in language DQ between the children who received early intervention and the normal hearing children. There was no significant correlation between the degree of hearing loss and language DQ in the children who received early intervention (P = 0.27). (2) The personal-social developmental quotient (DQ) of the children who received intervention was (101.40 +/- 7.66), significantly higher than that of the children who didn't receive intervention (83.94 +/- 22.09, P = 0.00), that were significantly lower than that of the children with normal hearing (P = 0.00). However, there were no significant difference in the personal-social DQ between the children who received early intervention and the children with normal hearing. No significant differences in the gross motor ability, fine motor ability and adaptive ability were observed between the two groups of children with hearing loss and normal hearing children. (3) The consonant pronunciation of the children with moderate to severe hearing loss who received early intervention was normal. Among those children only one case with profound hearing loss had/d/error. The consonant pronunciation of the children with moderate hearing loss who didn't receive early intervention of those was normal. One case with moderate-severe hearing loss and one case with severe hearing loss had/d/errors. Six cases with profound hearing loss had/d, m/errors. The tone of the children with moderate to severe hearing loss who received early intervention was normal. Three cases with profound hearing loss exhibited tone errors. Among the children who didn't receive early intervention, tone errors were found in two cases with moderate hearing loss, one case with moderate-severe hearing loss, one case with severe hearing loss, and twelve cases with profound hearing loss showed. CONCLUSION: The language, pronunciation and cognitive developments of the children who don't receive early intervention are significantly lower than those of the children with normal hearing. Early intervention can significantly improve the language, speech and cognitive abilities of children with hearing loss.

Child, Preschool↗

PubMed2006

Elongation factor-2 kinase: its role in protein synthesis and autophagy.

Elongation factor-2 kinase (eEF-2 kinase; Ca(2+)/calmodulin-dependent kinase III) controls the rate of peptide chain elongation. The activity of eEF-2 kinase is increased in many malignancies, yet its precise function in carcinogenesis remains unknown. Autophagy, a well-defined survival pathway in yeast, may also play an important role in oncogenesis. Furthermore, the autophagic response to nutrient deprivation is regulated by the mammalian target of rapamycin (mTOR). eEF-2 kinase lies downstream of mTOR and is regulated by several kinases in this pathway. Therefore, we studied the role of eEF-2 kinase in autophagy. Knockdown of eEF-2 kinase by RNA interference inhibited autophagy in several cell types as measured by light chain 3 (LC3)-II formation, acidic vesicular organelle staining, and electron microscopy. In contrast, overexpression of eEF-2 kinase increased autophagy. Furthermore, inhibition of autophagy markedly decreased the viability of glioblastoma cells grown under conditions of nutrient depletion. These results suggest that eEF-2 kinase plays a regulatory role in the autophagic process in tumor cells and may promote cancer cell survival under conditions of nutrient deprivation. Therefore, eEF-2 kinase activation may be a part of a survival mechanism in glioblastoma, and targeting this kinase may represent a novel approach to cancer treatment.

Animals↗

PubMed2006

Triptolide, a diterpenoid triepoxide, suppresses inflammation and cartilage destruction in collagen-induced arthritis mice.

Chinese herbal remedy Tripterygium wilfordii Hook. f. (TWHF) has been reported to be therapeutically efficacious in the treatment of rheumatoid arthritis (RA), but its in vivo actions have not been clarified. The purpose of this study was to investigate the effects of triptolide, a diterpenoid triepoxide extracted from TWHF, on inflammation and cartilage destruction in collagen-induced arthritis (CIA) model mice. Histological examination demonstrated that triptolide significantly reduced the inflammatory responses and cartilage damage in the joint tissues. Interestingly, triptolide interfered with CIA-augmented expression of matrix metalloproteinases-13 and -3, which are considered to be key enzymes in the pathological destruction of cartilage, and simultaneously augmented CIA-reduced tissue inhibitors of metalloproteinases-1 and -2 expression in the joints. Moreover, triptolide inhibited prostaglandin E(2) production via selective suppression of the production and gene expression of cyclooxygenase (COX)-2, but not COX-1. The levels of interleukin (IL)-1beta, tumor necrosis factor alpha and IL-6 were also decreased by triptolide in the joint tissues and sera as well as the suppression of CIA-mediated expression of their mRNAs in the joints. In addition, triptolide treatment in vivo was able to reduce an abundance of nuclear factor-kappaB, the transcriptional factor closely related to the inflammatory process, in articular cartilage and synovium in CIA mice. These results suggest that triptolide exerts novel chondroprotective and anti-inflammatory effects on RA, and the therapeutic action of TWHF on RA is, in part, due to the triptolide activities.

Animals↗

PubMed2006

Identification of the yeast R-SNARE Nyv1p as a novel longin domain-containing protein.

Using nuclear magnetic resonance spectroscopy, we establish that the N-terminal domain of the yeast vacuolar R-SNARE Nyv1p adopts a longin-like fold similar to those of Sec22b and Ykt6p. Nyv1p is sorted to the limiting membrane of the vacuole via the adaptor protein (AP)3 adaptin pathway, and we show that its longin domain is sufficient to direct transport to this location. In contrast, we found that the longin domains of Sec22p and Ykt6p were not sufficient to direct their localization. A YXX phi-like adaptin-dependent sorting signal (Y31GTI34) unique to the longin domain of Nyv1p mediates interactions with the AP3 complex in vivo and in vitro. We show that amino acid substitutions to Y31GTI34 (Y31Q;I34Q) resulted in mislocalization of Nyv1p as well as reduced binding of the mutant protein to the AP3 complex. Although the sorting of Nyv1p to the limiting membrane of the vacuole is dependent upon the Y31GTI34 motif, and Y31 in particular, our findings with structure-based amino acid substitutions in the mu chain (Apm3p) of yeast AP3 suggest a mechanistically distinct role for this subunit in the recognition of YXX phi-like sorting signals.

Adaptor Protein Complex 3↗

PubMed2006

Crystallization and preliminary X-ray crystallographic studies of Drep-3, a DFF-related protein from Drosophila melanogaster.

During apoptosis, DNA fragmentation is mainly mediated by the caspase-activated DFF40 nuclease. DFF40 exists as a heterodimeric complex with its inhibitor DFF45. Upon apoptosis induction, DFF45 is cleaved by caspases to allow DFF40 activation. Drep-3 is a recently identified regulator of the DFF40 system in Drosophila melanogaster. Here, Drep-3 was expressed with a C-terminal His tag in Escherichia coli and the protein was purified to homogeneity. Multi-angle light-scattering analysis showed that Drep-3 is a homotetramer in solution. Native and selenomethionine-substituted Drep-3 proteins were crystallized at 293 K and X-ray diffraction data were collected to 2.8 and 3.0 A resolution, respectively. The crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 56.9, b = 125.4, c = 168.7 A. The asymmetric unit is estimated to contain one homotetramer.

Cloning, Molecular↗