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Xiaodong Chen

Publications and source records attributed to Xiaodong Chen.

At least 19 recordsLinked to original sources
PubMed2026

A spatiotemporal resolution to genetic redundancy: MIR164 diversification coordinates development and metabolism in Brassica.

Whole-genome duplication (WGD) events create genetic redundancy, posing the evolutionary challenge of how paralogs escape functional overlap to drive innovation. Here, we demonstrate that the MIR164 family in Brassica oleracea resolves this redundancy through spatiotemporal niche partitioning. Following WGD, the family expanded to eight members, which subsequently underwent divergent selection-some preserved under purifying selection, while others showed signals of positive selection. This led to expression divergence, with Bol-MIR164a1 emerging as a key universally expressed paralog. CRISPR-Cas9 mutagenesis of Bol-MIR164a1 revealed its essential role in coordinating two pivotal traits: leaf serration and leaf coloration. Mutants exhibited enhanced leaf serration due to spatial deregulation of CUC2 at organ boundaries, concurrently with yellow-green leaves and elevated flavonoid accumulation. We mechanistically linked the metabolic phenotype to direct transactivation of the anthocyanidin reductase (ANR) promoter by NAC100, alongside its upregulation of chlorophyll catabolism genes. Our findings establish a paradigm in which spatial segregation of target gene expression domains enables a single, widely expressed miRNA paralog to resolve genetic redundancy by independently orchestrating distinct regulatory programs. This provides a fundamental framework for understanding complex trait evolution in polyploids. This allows a single miRNA locus to independently orchestrate both morphological patterning and metabolic programming, providing a fundamental framework for understanding complex trait evolution in polyploid crops.

MicroRNAs↗
PubMed2025

Altered ruminal microbiome tryptophan metabolism and their derived 3-indoleacetic acid inhibit ruminal inflammation in subacute ruminal acidosis goats.

BACKGROUND: Subacute ruminal acidosis (SARA) is a digestive disorder that often severely jeopardizes the health and lactation performance of ruminants fed a high-energy diet. Different dairy ruminants exhibit varying degrees of inflammation accompanied by variations in the rumen microbiota when SARA occurs. Our understanding of the occurrence of SARA and varying degrees of rumen epithelial inflammation is lacking. Hence, we performed rumen metagenomic, metagenome-assembled genome and metabolomic analyses, with transcriptome and single-nucleus RNA sequence analyses, to explore the microbial mechanism of SARA occurrence and different degrees of inflammation. RESULTS: A total of 36 goats fed two diets with gradually increasing levels of rumen-degradable starch (RDS) were included in this study, and SARA goats fed 70% concentrate diets supplemented with whole corn (HGW-SARA) and SARA goats fed 70% concentrate diets supplemented with crushed corn (HGC-SARA) were identified. Moreover, 11 goats fed a control basal diet, named LGW-CON, were also included. Compared with those in the LGW-CON group, the rumen fermentation capacity was enhanced, accompanied by ruminal epithelial and systemic inflammation, in goats from HGW-SARA and HGC-SARA. Between them, HGC-SARA goats presented less inflammation. Notably, the ruminal inflammation-related pathways were increased only in the HGW-SARA group but not in the HGC-SARA group. Metagenomic analysis revealed that the β diversity of SARA goats was significantly different from that of LGW-CON goats. Ruminococcus significantly increased in both SARA groups, whereas Prevotella and Bacteroidales significantly decreased, which was accompanied by a decrease in cellulose and hemicellulose enzymes and an increase in lysozymes and lipopolysaccharide synthesis enzymes. Multi-omics analysis of the ruminal contents and tissues suggested that epithelial inflammation was caused by disturbed ruminal microbiome-induced Th17 cell differentiation and IL-17 signalling pathway activation. Comparative analyses between the HGW-SARA and HGC-SARA groups highlighted the importance of Selenomonas and Bifidobacterium, as well as bacterial tryptophan metabolism, in the production of 3-indoleacetic acid, which mitigated ruminal epithelial inflammation by modulating Th17 cells and inhibiting IL-17 signalling. Ruminal microbiota transplantation from HGW-SARA goats to healthy dairy goats and mice revealed the role of microbes in epithelial inflammation. Additionally, 3-indoleacetic acid supplementation reduced rumen inflammation and the IL-17 concentration in the serum, improved VFAs absorption, and enhanced milk production. CONCLUSIONS: This study unveiled that after SARA was induced by high-concentrate feeding, the rumen homeostasis was disrupted, and rumen fiber degradation capacity of dairy goats decreased, but the LPS synthesis capacity increased, and inflammation of the rumen epithelium was observed. However, the ruminal microbial species from the Bifidobacterium and Selenomonas genera and bacterial 3-indole acetic acid are pivotal in mitigating ruminal epithelial inflammation during SARA in dairy goats. This could potentially be attributed to the modulation of ruminal Th17 cell proportions and the inhibition of IL-17 signalling pathways. Video Abstract.

Rumen↗
PubMed2006

Hierarchical luminescence patterning based on multiscaled self-assembly.

This communication describes a procedure for fabrication of hierarchical luminescence patterns based on the template-assisted assembly of CdSe nanocrystals on a self-assembled structure with green-emitting microstripes, as well as the photoinduced fluorescence enhancement of CdSe nanocrystals and photobleaching of dyes. The technique is low-cost and high-throughput and can be extended to many material combinations.

Journal Article↗
PubMed2006

Cloning, comparative characterization of porcine SCAP gene, and identification of its two splice variants.

Sterol responsive element binding protein (SREBP) cleavage-activating protein (SCAP) is the key regulator of activation of SREBPs, which stimulate most enzymes in cholesterol and lipid synthesis. In order to investigate the molecular basis of lipid metabolism in the pig, a unique model for fat deposition, we isolated and characterized the porcine SCAP. The 4,096-bp full-length porcine SCAP cDNA contains an open reading frame of 3,840 bp. The predicted SCAP protein consists of 1,280 amino acids of 55-92% identity with its vertebrate counterparts. The porcine SCAP gene consists of at least 19 exons and 18 introns, which span over 13 kb of the genome. The porcine SCAP gene was mapped to chromosome 13q21-22 using a porcine-rodent somatic cell hybrid panel. Comparison of SCAP genomic structures from various species revealed intron losses in porcine, Tetraodon and fugu SCAP, and intron gains in cow and chicken SCAP. Moreover, we isolated two novel splicing SCAP variants with 193-bp (variant 2) in-frame deletion from testis and a variant with 291-bp (variant 3) in-frame deletion from liver and muscle, which may affect the function of the porcine SCAP. In conclusion, the intron gains and losses appear to have contributed to the shape of the modern SCAP family. The splice variants detected, first to be reported in any species, may be involved in the particulars of the fat metabolism in the pig. Our data lay foundation for further study of SCAP function in this species.

Alternative Splicing↗
PubMed2006

Langmuir-Blodgett patterning of phospholipid microstripes: effect of the second component.

We systematically describe the striped pattern formation of the mixed monolayers of 1,2-di(2,4-octadecadienoyl)-sn-glycero-3-phosphocholine (DOEPC) and l-alpha-dipalmitoylphosphatidylcholine (DPPC) from the liquid expanded (LE) phase onto a mica surface by Langmuir-Blodgett (LB) transfer. The addition of the second component, DOEPC, strongly affects the formation of DPPC stripe patterns. When the molar ratio of DPPC and DOEPC is 1:0.1, the horizontal stripes dominate, while in the case of pure DPPC monolayer, there are three kinds of patterns: horizontal stripes, grids, and vertical stripes. The width and periodicity of stripes formed from the mixed monolayers are ca. 4-5 times smaller than those formed from pure DPPC patterns at the same transfer conditions, while the widths of channels are similar. A phase shift of substrate-mediated microphase separation in the two-component system during LB transfer is considered to be the mechanism for the influence of the second component on the formation of DPPC stripe patterns.

Journal Article↗
PubMed2006

Gene organization, alternate splicing and expression pattern of porcine visfatin gene.

Visfatin is a newly discovered visceral fat-specific adipocytokine. It is upregulated in obesity and exerts insulin-mimetic effects in various tissues in human and mouse. We reported here the cloning and characterization of porcine visfatin, its three alternate splicing variants. Sequence analysis indicated that variant 1 is the predominant form among species, which contains an open reading frame of 1473 bp encoding a 52-kDa protein of 491 amino acids. While the other two variants were predicted to encode two 3' truncated proteins due to early termination. The nucleotide and amino acid sequences deduced from variant 1 were conservative across species. The porcine visfatin gene was composed of 11 exons at least and had exactly the same exon/intron structure as the human orthologs. Nested PCR showed that variants 1 and 3 were ubiquitously expressed in porcine tissues and that variant 2 was expressed in most tissues examined with exception of testis and liver. The discovery of the three variants of visfatin in porcine would be useful to the further investigation of the function of the visfatin gene.

Alternative Splicing↗
PubMed2006

Control of hypertrophic scar from inception by using xenogenic (porcine) acellular dermal matrix (ADM) to cover deep second degree burn.

OBJECTIVE: We have spent 7 years to investigate the method of applying porcine acellular dermal matrix (ADM) on deep partial thickness burn wound until the wound heals without dressing change. Known as "Feng's pig skin method" by our hospital, the method appears to encourage rapid re-epithilization with minimum scarring. METHOD: The deep partial thickness burn wound was rinsed cleanly under anesthesia when the patient admitted. ADM was applied on the wound after the detached epidermis was thoroughly removed, wrapped and fixed by sterile gauze and bandages. The dressing was removed within two weeks and the wound completely healed. The outcome of the treatment was analyzed by using the modified Vancouver Burn Scar Assessment Scale. RESULT: All the wounds healed with one dressing within 2 weeks, and the time of wound re-epithelialization shortened to 7-12 days. Scar hyperplasia did not occur, or it was greatly ameliorated compared with traditional treatment after a followed-up period of 3 months to 2 years. The Scar Index was significant lower than that of the traditional exposure method. CONCLUSION: Using ADM to cover deep second degree burn can preserve maximally residual dermal tissue and epithelium, help accelerate the regeneration of epithelial and stem cells, thus shorten the healing time, remodel the skin structure, and consequently has the effect of controlling hypertrophic scar at inception.

Adolescent↗
PubMed2006

[Three-dimensional moston estimation of coronary artery from single-plane cineangiogram sequences].

This paper presents a method for estimating three-dimensional (3D) motion of coronary arteries from single-plane X-ray angiogram sequences on two views. Firstly, original images are preprocessed and two-dimensional (2D) vessel skeletons are extracted. 2D motion estimation is performed along the skeletons in two images. Then geometrical transformation matrix between views is obtained based on perspective projection model for X-ray angiography system, and 3D coordinate of spatial points are calculated. The 3D motion estimation and reconstruction algorithm is applied along the two image sequences to accomplish 3D reconstruction of vessel skeletons and motion vectors between consecutive time instants. Its effectiveness has been demonstrated on clinical single-plane coronary artery angiograms and potential errors are discussed.

Algorithms↗
PubMed2006

Resistin overexpression impaired glucose tolerance in hepatocytes.

Resistin is a 12.5-kDa cysteine-rich protein secreted from adipose tissue and is an important factor linking obesity with insulin resistance. Here, we investigated the effect of resistin on glucose tolerance in adult human hepatocytes (L-02 cells). In this study, resistin cDNA was transfected into L-02 cells, and glucose concentration and glucokinase activity were determined subsequently. The data indicated resistin impaired, insulin-stimulated glucose utilization, which implied liver was a target tissue of resistin. To understand its molecular mechanism, mRNA levels of key genes in glucose metabolism and insulin signaling pathway were analyzed. The results demonstrated resistin-stimulated expression of glucose-6-phosphatase (G6Pase), sterol regulatory element-binding protein 1c (SREBP1c) and suppressor of cytokine signaling 3 (SOCS-3), repressed expression of peroxisome proliferator-activated receptor gamma (PPARgamma) as well as insulin receptor substrate 2 (IRS-2). Given that glucokinase (GK) activity and glucose transporter 2 (GLUT2) expression were not altered, we presumed that resistin did not effect them. Moreover, resistin lowered mRNA levels of IRS-2 while stimulating SOCS-3 expression, which suggests it impairs glucose tolerance by blocking the insulin signal transduction pathway.

Adult↗
PubMed2005

Unconventional air-stable interdigitated bilayer formed by 2,3-disubstituted fatty acid methyl esters.

A single-chain fatty acid methyl ester, racemic anti-3-fluoro-2-hydroxyeicosanoic acid methyl ester (beta-FHE), forms an unconventional air-stable interdigitated bilayer at the air-water interface. The interdigitated bilayer transferred onto solid substrate by the Langmuir-Blodgett (LB) technique keeps air-stable without any substrate modification or protein inclusion. There are two visible plateaus in the surface pressure-molecular area (pi-A) isotherms of beta-FHE Langmuir film during continuous compression. According to Brewster angle microscopy (BAM), grazing incidence X-ray diffraction (GIXD), X-ray reflectivity (XR), fluorescence microscopy (FM), and atomic force microscopy (AFM) measurements, the first plateau is attributed to the coexistence of liquid expanded (LE) and liquid condensed (LC) phases in the monolayer, while the second plateau is interpreted as the transition from LC monolayer to interdigitated bilayer. The coupling between tilt and curvature associated with the packing mismatch between headgroup and chain gives rise to buckling and folding of the monolayer, leading to the transition of the LC monolayer to a bilayer structure. The diffusion-limited aggregation (DLA) model is applied to describe the formation of the fractal structures of the bilayer as observed in the second plateau. In addition, the transition between monolayer and bilayer is reversible. The present works are interesting for understanding biological processes, for example, the behavior of lung surfactants.

Air↗
PubMed2005

Transcriptional regulation of the resistin gene.

Resistin, which is a protein that is secreted exclusively by adipocytes, plays an important role in insulin resistance and adipocyte differentiation. Adipocytes express significant amounts of resistin mRNA, while preadipocytes express low levels of resistin mRNA. The mechanism that causes this difference is unclear. Therefore, we studied the mechanism regulating resistin expression and the roles of different transcriptional factors in this process. The results from fluorescent photography and semi-quantitative RT-PCR showed that sterol regulatory element-binding protein 1c (SREBP1c) and cyclic AMP response-element-binding protein (CREB) had no effect on resistin expression. By contrast, CCAAT/enhancer-binding protein-alpha (C/EBPalpha) increased resistin mRNA levels both in 3T3-L1 preadipocytes and in 293T cells. The relative increase in the amount of resistin mRNA in the 293T cells was much larger than that in the 3T3-L1 preadipocytes. Moreover, while C/EBPalpha was necessary for resistin expression, we found that up-regulating C/EBPalpha levels alone was not sufficient to induce a similar level of resistin in preadipocytes to that in adipocytes.

3T3-L1 Cells↗
PubMed2005

Influence of surfactant molecular structure on two-dimensional surfactant-DNA complexes: Langmuir balance study.

In this paper, we used two simplified methods to understand the influence of surfactant molecular structure on the properties of surfactant-DNA complexes. First, we selected Langmuir balance technique, a two-dimensional (2D) method, which allows complex formation under equilibrium-like conditions, avoiding some of the inherent problems involved in solution. Secondly, two series of simple quaternary ammonium surfactants were used. The cationic surfactant-DNA complex monolayers were formed at the air-water interface through the electrostatic interaction between the ammonium groups of the surfactants and the phosphate groups of DNA at the air-water interface. Combining the results of pi-A isotherms, pi-t isotherms, and atomic force microscopy (AFM) measurements, it was found that the surfactant molecular structures affect the surface properties and morphologies of 2D surfactant-DNA complexes. We expect that the study of the properties of 2D surfactant-DNA complexes will help us to understand the physicochemical properties of surfactant-DNA complexes, which are important for gene delivery.

Aluminum Silicates↗
PubMed2005

Phase behavior of 2,3-disubstituted methyl octadecanoate monolayers at the air-water interface.

The phase behavior of 2,3-disubstituted methyl octadecanoate monolayers at the air-water interface is studied by film balance and a Brewster angle microscope (BAM). The comparison of the surface pressure-molecular area (pi-A) isotherms with the corresponding BAM images provides information on the phase behavior of the monolayers. Variations in the phase behavior of different 2,3-disubstituted methyl octadecanoate monolayers can be correlated with the size of the headgroups, the interactions between the polar molecular moieties and the subphase, and the intermolecular interactions. The enlarging of the headgroups makes forming a condensed monolayer difficult for the molecules, even after introduction of substituents giving rise to the formation of hydrogen bonds between the molecules, which may balance the steric repulsion and stabilize the monolayers. Model calculations of the two-dimensional lattice structure of the 2,3-disubstituted methyl octadecanoates on basis of the pg and p1 space group are performed and correspond well with the experimental results.

Air↗
PubMed2005

PTEN promoter methylation and protein expression in normal early placentas and hydatidiform moles.

OBJECTIVE: To investigate the relationship between PTEN promoter methylation and protein expression, and the possible involvement of the PTEN gene in development of gestational trophoblasts and the pathogenesis of hydatidiform moles. METHODS: DNA was extracted from choria of normal early placentas, partial hydatidiform moles, complete hydatidiform moles, and invasive moles, and overdigested by methylation-sensitive endonuclease HpaII. The PTEN promoter was amplificated by polymerase chain reaction. PTEN protein expression was detected by immunohistochemistry. RESULTS: In partial and complete hydatidiform moles, the PTEN promoter methylation rate was significantly higher than in early placentas (72%, 59.4%, 14.3%; P = .000, .002, respectively), and the PTEN protein expression rate was significantly lower than in early placentas (9.1%, 4.5%, 90.5%; P = .000, .000, respectively). However, partial hydatidiform moles, complete hydatidiform moles, and invasive moles were not significant different in terms of PTEN promoter methylation and protein expression. CONCLUSIONS: These findings suggest that the regulation of PTEN expression may play an important role in the development of the early gestational trophoblast and in the pathogenesis of hydatidiform mole, but not in its malignant transformation.

DNA Methylation↗
PubMed2004

The pH stimulated reversible loading and release of a cationic dye in a layer-by-layer assembled DNA/PAH film.

Through the layer-by-layer (LbL) deposition method, DNA was assembled into an ultrathin film with a cationic poly(allylamine hydrochloride) (PAH). The loading and release of a typical cationic dye, 5, 10, 15, 20-tetrakis(4-N-methylpyridyl)porphine-tetra-(p-toluenesulfonate) (TMPyP), in the DNA/PAH films were investigated. It has been found that the LbL-assembled DNA/PAH film was very stable in both acidic and alkaline solutions. Stimulated by the pH change of the dye solution, the dye can be easily loaded into or released from the DNA/PAH film. In an alkaline solution, the dye could be rapidly loaded into the DNA/PAH film at room temperature, while in an acidic solution, the dye could be rapidly released. The mechanism of such pH-stimulated loading and release in the DNA/PAH film was discussed. It was further observed that the loading and release of the dye in the DNA/PAH film was reversible upon pH change and the process could be repeated many times.

Cations↗
PubMed2004

Mismatch repair gene promoter methylation and expression in hydatidiform moles.

METHODS: In this study, to investigate the significance of mismatch repair genes (MMR) promoter methylation and expression in the pathogenesis and malignant transformation of hydatidiform moles, we assayed promoter methylation and protein expression of the MMR genes hMLH1 and hMSH2 in gestational trophoblastic diseases (GTDs). DNA was extracted from normal placentas, partial hydatidiform moles, complete hydatidiform moles, and invasive moles, over-digested by methylation-sensitive endonuclease Hpa II, and then the promoters were amplificated by polymerase chain reaction. The protein expression was detected by immunohistochemistry. RESULTS: In the normal placentas, neither hMLH1 nor hMSH2 promoter methylation was detected. Expression of hMLH1 and hMSH2 in cytotrophoblasts was strongly positive. In partial hydatidiform moles and complete hydatidiform moles, hMLH1 and hMSH2 promoter methylation rates were significantly higher than that of normal placentas (P = 0.000), and the protein expression in cytotrophoblasts was significantly lower (P = 0.000). In the invasive moles, hMLH1 and hMSH2 promoter methylation was not significantly different compared with the partial hydatidiform moles and complete hydatidiform moles (P > 0.05). Expression of hMLH1 in the invasive moles (54.5%, 6 out of 11) was not significantly different compared with the partial hydatidiform moles and complete hydatidiform moles (P > 0.05). But hMSH2 expression in the invasive moles (36.5%, 4 out of 11) was weaker than that in complete hydatidiform moles (P = 0.044). Promoter methylation and less expression of hMSH2 were correlated in complete hydatidiform moles (P = 0.001) and invasive moles (P = 0.039). CONCLUSIONS: These results indicated that strong expression of hMLH1 and hMSH2 in the cytotrophoblasts of normal placentas may maintain genome stability. Promoter methylation and down-regulation of the expression of hMLH1 and hMSH2 are probably involved in the pathogenesis of hydatidiform moles.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Induced chirality of binary aggregates of oppositely charged water-soluble porphyrins on DNA matrix.

The induced chirality of achiral binary aggregates of meso-tetrakis(4-N-methylpyridyl)porphyrine (TMPyP) and meso-tetrakis(4-sulfonatophenyl)porphyrine (TPPS) on a deoxyribonucleic acid (DNA) matrix was investigated. Although the negatively charged TPPS did not show induced chirality in DNA solution due to the electrostatic repulsion, induced chirality was obtained through the addition of a positively charged TMPyP. It was confirmed that the induced chirality was due to the binary complex formation between TPPS and TMPyP on the DNA matrix. Moreover, the induced chirality depended on the relative molar ratio of TPPS to TMPyP (r) and the binding modes of the complex to DNA. When r<1, induced circular dichroism (CD) spectrum of the ternary complex was similar to that of intercalated TMPyP into DNA. For r=1, the induced CD spectrum showed a reversed biphasic signal due to the complex of TMPyP and TPPS stacking along the DNA surface. At a higher r value (>1), there was an induced CD signal at 482 nm attributed to a lateral shifted arrangement of heteroaggregate of TPPS and TMPyP on DNA matrix where TMPyP acted as a spacer to mediate the growth of heteroaggregates. Increasing the concentration of sodium chloride in the solution would favor the formation of the lateral shifted arrangement of heteroaggregate of TPPS and TMPyP. The resonance light scattering (RLS) spectra confirmed the above results. Analysis of the CD spectral changes in DNA conformation showed that during the binary complex formation of TPPS and TMPyP, the intercalated TMPyP could be 'pulled out' from the base pairs of DNA, which might be useful in gene therapy. A model was proposed to account for these observations.

DNA↗