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Machine learning-based integration develops a novel lysosome-related prognostic signature associated with prognosis and immune infiltration landscape in acute myeloid leukemia.

BACKGROUND: Lysosomes are essential for intracellular degradation and recycling, and changes in their function significantly contribute to tumor growth. Nonetheless, the exact role of lysosome-related genes (LRGs) in the pathogenesis of acute myeloid leukemia (AML) is still inadequately comprehended. METHODS: Differentially expressed LRGs (DE-LRGs) between AML and control groups were identified using AML-related data extracted from the Gene Expression Omnibus (GEO). The LRGs-related prognostic genes were identified and the risk model was established using univariate COX regression analysis and machine learning algorithms, based on the data obtained from The Cancer Genome Atlas (TCGA). Subsequently, we performed comprehensive analyses regarding clinical features, functional pathways, immune microenvironment, and chemotherapeutic drugs sensitivity between the high- and low-risk groups. Reverse transcription Quantitative polymerase chain reaction (RT-qPCR) and western blot were adopted to validate the expression of prognostic genes in human bone marrow-derived cell line HS-27 A and human AML cell line MOLM-13. RESULTS: Through comprehensive analysis, a risk model was developed utilizing ten LRGs (ATP6V0E2, CALCRL, TMEM165, GZMB, HCK, TCIRG1, CD1D, GPRASP1, ABCA1, and NAGA), and this model was further validated using GEO datasets. Significant differences in clinical characteristics, functional pathways, immune microenvironment characteristics, and chemotherapeutic drug sensitivity were observed between the two risk groups In vitro validation experiment illustrated that the expression trends of ATP6V0E2, TMEM165, and ABCA1 were consistent with our bioinformatics analysis. CONCLUSION: Our study demonstrates that lysosome-associated signature might forecast the prognosis of AML patients and offer guidance for subsequent immunotherapy and chemotherapy strategies.

Acute myeloid leukemia↗

Quantitative proteomic analysis of the brain reveals the potential antidepressant mechanism of Jiawei Danzhi Xiaoyao San in a chronic unpredictable mild stress mouse model of depression.

OBJECTIVE: To reveal the antidepressant mechanisms of Jiawei DanZhiXiaoYaoSan (,JD) in chronic unpredictable mild stress (CUMS)-induced depression in mice. METHODS: Using the CUMS mouse model of depression, the antidepressant effects of JD were assessed using the sucrose preference test (SPT), forced swimming test (FST), and tail suspension test (TST). Tandem mass tag (TMT)-based quantitative proteomic analysis of the brain was performed following JD treatment. Hierarchical clustering, Gene Ontology function annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and protein-protein interactions (PPIs) were used to analyze differentially expressed proteins (DEPs), which were further validated using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. RESULTS: Behavioral tests confirmed the anti-depressant effects of JD, and bioinformatics analysis revealed 59 DEPs, including 33 up-regulated and 26 down-regulated proteins, between the CUMS and JD-M groups. KEGG and PPI analyses revealed that neuro-filament proteins and the Ras signaling pathway may be key targets of JD in the treatment of depression. qRT-PCR and Western blotting results demonstrated that CUMS reduced the protein expression of neurofilament light (NEFL) and medium (NEFM) and inhibited the phosphorylation of extracellular regulated kinase 1/2 (ERK1/2), whereas JD promoted the phosphorylation of ERK1/2 and up-regulated the protein expression of NEFL and NEFM. CONCLUSIONS: The antidepressant mechanism of JD may be related to the up-regulation of p-ERK1/2 and neurofilament proteins.

Animals↗

Comprehensive Analysis of miRNAs and Predicted Protein Interaction Networks in Skeletal Muscle Development of Myostatin-Deficient Rabbits.

Myostatin (MSTN), encoded by the MSTN gene, is a critical negative regulator of skeletal muscle mass. This study aims to identify and characterize the miRNAs involved in the development of the double-muscling phenotype in MSTN-deficient rabbits. We performed high-throughput sequencing to analyze the miRNA expression profiles in gluteus maximus tissue from wild type (MSTN+/+) and MSTN-KO (MSTN+/- and MSTN-/- inclusive) rabbits. Differentially expressed miRNAs (DEmiRNAs) were identified, and their potential target genes were predicted. Functional enrichment analysis of these target mRNAs was conducted using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database to elucidate the involved biological pathways and regulatory networks. A total of 25 DEmiRNAs (13 downregulated and 12 upregulated, |log2FC|&#x2009;&#x2265;&#x2009;1.0, adjusted p&#x2009;<&#x2009;0.05) and 1178 differentially expressed mRNAs (408 upregulated and 770 downregulated, |log2FC|&#x2009;&#x2265;&#x2009;2.0, adjusted p&#x2009;<&#x2009;0.05) were identified in MSTN-KO compared to MSTN+/+ rabbits. Bioinformatics analysis revealed that the target genes of these DEmiRNAs were significantly enriched in key pathways governing muscle growth and metabolism, including the PI3K-Akt signaling pathway, MAPK signaling pathway, and pathways related to ECM-receptor interaction and insulin signaling. Notably, many predicted target mRNAs are expressed by genes that encode key inhibitors of myogenesis (e.g., HDAC4) and major extracellular matrix components (e.g., COL4A3, POSTN). Our results demonstrate that MSTN deficiency induces a distinct and widespread change in the miRNA expression landscape of skeletal muscle.

Animals↗

Screening and identification of the ncRNA-mRNA regulatory network associated with DNA methylation in goose embryonic myoblasts.

BACKGROUND: Local goose breeds Shitou and Wuzong exhibit distinct growth rates, implying divergent embryonic muscle development. This study used embryonic myoblasts from the Magang goose, an established model with superior growth traits, to explore the underlying common regulatory mechanisms. Extending our previous findings that 5-AZA (DNA methylation inhibitor) and BC339 (DNA hydroxylation inhibitor) oppositely affect myoblast proliferation and differentiation, we performed whole-transcriptome sequencing on inhibitor-treated goose embryonic myoblasts. This aimed to identify DNA methylation-mediated ncRNA-mRNA networks governing myoblast fate, with key interactions being functionally validated. RESULT: 5-AZA significantly promotes cell proliferation and differentiation by inhibiting DNA methyltransferase activity and reducing DNA methylation levels, whereas BC339 significantly suppresses cell proliferation and differentiation by inhibiting demethylation and increasing DNA methylation levels. Specifically, we identified 6,309 mRNAs, 579 lncRNAs, 194 miRNAs, and 825 circRNAs that were differentially expressed in response to 5-AZA and BC339 treatment. Based on GO and KEGG enrichment analyses, differentially expressed genes related to muscle development were selected to construct a ceRNA network. This network comprises 5 differentially expressed lncRNAs (DELs: MSTRG.17572.1, XR_001211738.1, MSTRG.1886.1, XR_001212555.1, MSTRG.8995.2), 2 differentially expressed circRNAs (DECs: novel_circ_029953, novel_circ_017636), 11 differentially expressed miRNAs (DEMs: miR-383-x, miR-10174-y, miR-191-x, miR-24-x, miR-9619-y, novel-m0303-5p, novel-m0105-3p, miR-204-x, miR-211-z, novel-m0075, miR-26-y), 5 differentially expressed genes (DEGs: KIF3A, CCND1, PPM1A, Table&#xa0;2, TGFBR1), forming a total of 24 interactions. This study identified miR-9619-y as a critical negative regulator of goose embryonic myoblast development through targeted inhibition of CCND1. Dual-luciferase reporter assays confirmed the direct binding of miR-9619-y to the 3'-untranslated region of CCND1. Functional experiments demonstrated that overexpression of miR-9619-y significantly reduced the EdU-positive cell ratio and myotube area percentage, accompanied by cell cycle arrest at the G0/G1 phase. Conversely, inhibition of miR-9619-y promoted myoblast proliferation and differentiation while decreasing the proportion of cells in G0/G1 phase. During the proliferation stage, miR-9619-y overexpression significantly suppressed CCND1 expression at both mRNA and protein levels, down-regulated MyoD expression, and reduced Myf5 mRNA abundance; whereas miR-9619-y inhibition up-regulated these genes and their corresponding proteins. During the differentiation stage, overexpression of miR-9619-y similarly decreased the mRNA levels of CCND1, Myh1, and MyoG, as well as the protein levels of MyHC and CCND1, with inhibition producing the opposite effects. CONCLUSION: In this study, we predicted a ceRNA network based on bioinformatics analysis governing goose embryonic myoblast development, identifying key molecular components including mRNAs, miRNAs, lncRNAs, and circRNAs, along with 24 regulatory axes. Functional experiments further demonstrated that miR-9619-y arrests cell cycle progression and negatively regulates the proliferation and differentiation of goose embryonic myoblasts, as evidenced by its impact on both the mRNA and protein expression of key myogenic factors through targeted inhibition of CCND1. These findings, together with the bioinformatically predicted ceRNA network, suggest potential complex post-transcriptional regulatory mechanisms underlying myogenesis in geese and offer candidate molecular targets for genetic improvement of meat production performance in waterfowl breeding programs.

Animals↗

A survey of genes in the Atlantic salmon (Salmo salar) as identified by expressed sequence tags.

We describe the construction and quality analysis of six cDNA libraries from the liver, ovary, testis, brain, spleen and muscle tissues of adult Atlantic salmon. The cDNA libraries were then screened with total cDNA probes to catalogue clones representing the abundant and rare mRNA populations in each tissue. Subsequently, the 5'-terminal DNA sequences of 1152 cDNA clones, composed of 96 clones from each of the abundant and rare mRNA populations in the six tissues, were determined. Bioinformatic analysis revealed that 510 (50%) of the salmon expressed sequence tags (ESTs) of sufficient length showed significant homology to previously identified genes from salmonid and other species, while 517 (50%) of salmon ESTs were unidentified or novel. After accounting for multi-EST redundancy, the 510 identified ESTs provided DNA sequence markers for 178 salmon genes which are listed in terms of tissue of origin and mRNA abundance class.

Animals↗

Molecular dissection of the S-adenosylmethionine-binding site of phosphatidylethanolamine N-methyltransferase.

Phosphatidylethanolamine N-methyltransferase (PEMT) is a quatrotopic membrane protein that catalyzes the conversion of phosphatidylethanolamine to phosphatidylcholine through three sequential methylation reactions. Analysis of mice lacking a functional PEMT gene revealed a severe reduction in plasma homocysteine levels. Homocysteine is generated by the hydrolysis of S-adenosylhomocysteine, which is also a product of the PEMT reaction. To gain insight into the PEMT transmethylation reaction and the mechanism by which PEMT regulates homocysteine levels, we sought to define residues that are required for binding of the methyl group donor, S-adenosylmethionine (AdoMet). Bioinformatic analysis of the predicted amino acid sequence of human PEMT identified two putative AdoMet-binding motifs (98GXG100 and 180EE181). Site-directed mutagenesis experiments demonstrated the requirement for the conserved motifs in PEMT specific activity. Analysis of the AdoMet binding ability of mutant recombinant PEMT derivatives established that residues Gly100 and Glu180 are essential for binding of the AdoMet moiety. A significantly elevated KD with respect to AdoMet is observed following conservative mutagenesis of residues Gly98 (400 pmol) and Glu181 (666.7 pmol), relative to the unmodified enzyme (303.1 pmol), suggesting that these residues also participate in AdoMet binding. A model positions two separate AdoMet-binding motifs of PEMT in close proximity at the external leaflet of the endoplasmic reticulum membrane.

Amino Acid Sequence↗

[Novel full-length cDNA cloning from normal adrenal gland and pheochromocytoma and functional prediction].

OBJECTIVE: To investigate methodology of cloning full-length cDNA from tissues of normal adrenal gland and pheochromocytoma and predict their function. METHODS: 104 samples from normal adrenal gland and 22 samples from pheochromocytoma were examined by expressed sequence tags (EST) sequencing, bioinformatics analysis, in silico cloning, rapid amplification of cDNA ends and RT-PCR. RESULTS: Among the 126 samples of novel full-length cDNA cloning 104 were from normal adrenal gland, and 22 from pheochromocytoma (PC). Among the novel genes 50 were cloned by direct sequencing of clones, 74 by in silico cloning, and 2 by rapid amplification of cDNA ends, and the localization of chromosomes was made with UniGene searching and radiation hybrid (RH) procedure. Comparison of homology and analysis of motif or domain showed that some genes may be important functional genes, such as those coding signaling proteins, proteins associated with ion channel, enzymes involved in hormone production, important transcription factors, translation initiation factors, etc. 7 of the novel full-length cDNAs are new isoforms produced by alternative splicing. CONCLUSION: 126 novel full-length cDNAs have been cloned from adrenal tissues by large-scale EST sequencing and bioinformatic tools in a rather short time, some of which may play an important role in regulating adrenal functions and tumorigenesis of adrenal gland.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

Structural, genetic and functional characterization of the flagellin glycosylation process in Helicobacter pylori.

Mass spectrometry analyses of the complex polar flagella from Helicobacter pylori demonstrated that both FlaA and FlaB proteins are post-translationally modified with pseudaminic acid (Pse5Ac7Ac, 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno -n o n-ulosonic acid). Unlike Campylobacter, flagellar glycosylation in Helicobacter displays little heterogeneity in isoform or glycoform distribution, although all glycosylation sites are located in the central core region of the protein monomer in a manner similar to that found in Campylobacter. Bioinformatic analysis revealed five genes (HP0840, HP0178, HP0326A, HP0326B, HP0114) homologous to other prokaryote genes previously reported to be involved in motility, flagellar glycosylation or polysaccharide biosynthesis. Insertional mutagenesis of four of these homologues in Helicobacter (HP0178, HP0326A, HP0326B, HP0114) resulted in a non-motile phenotype, no structural flagella filament and only minor amounts of flagellin protein detectable by Western immunoblot. However, mRNA levels for the flagellin structural genes remained unaffected by each mutation. In view of the combined bioinformatic and structural evidence indicating a role for these gene products in glycan biosynthesis, subsequent investigations focused on the functional characterization of the respective gene products. A novel approach was devised to identify biosynthetic sugar nucleotide precursors from intracellular metabolic pools of parent and isogenic mutants using capillary electrophoresis-electrospray mass spectrometry (CE-ESMS) and precursor ion scanning. HP0326A, HP0326B and the HP0178 gene products are directly involved in the biosynthesis of the nucleotide-activated form of Pse, CMP-Pse. Mass spectral analyses of the cytosolic extract from the HP0326A and HP0326B isogenic mutants revealed the accumulation of a mono- and a diacetamido trideoxyhexose UDP sugar nucleotide precursor.

Amino Acid Sequence↗

DNA microarrays and likelihood ratio bioinformatic methods: discovery of human melanocyte biomarkers.

In this article, some of the advantages and limitations of DNA microarray technologies for gene expression profiling are summarized. As a model experiment, DermArray DNA microarrays were utilized to identify potential biomarkers of cultured normal human melanocytes in two different experimental comparisons. In the first case, melanocyte RNA was compared with vastly dissimilar non-melanocytic RNA samples of normal skin keratinocytes and fibroblasts. In the second case, melanocyte RNA was compared with a primary cutaneous melanoma line (MS7) and a metastatic melanoma cell line (SKMel-28). The alternative approaches provide dramatically different lists of 'normal melanocyte' biomarkers. The most robust biomarkers were identified using principal component analysis bioinformatic methods related to likelihood ratios. Only three of 25 robust biomarkers in the melanocyte-proximal study (i.e. melanocytes vs. melanoma cells) were coincidentally identified in the melanocyte-distal study (i.e. melanocytes vs. non-melanocytic cells). Selected up-regulated biomarkers of melanocytes (i.e. TRP-1, melan-A/MART-1, silver/Pmel17, and nidogen-2) were validated by qRT-PCR. Some of the melanocytic biomarkers identified here may be useful in molecular diagnostics, as potential molecular targets for drug discovery, and for understanding the biochemistry of melanocytic cells.

Aged↗

Genomic sequence of C1, the first streptococcal phage.

C(1), a lytic bacteriophage infecting group C streptococci, is one of the earliest-isolated phages, and the method of bacterial classification known as phage typing was defined by using this bacteriophage. We present for the first time a detailed analysis of this phage by use of electron microscopy, protein profiling, and complete nucleotide sequencing. This virus belongs to the Podoviridae family of phages, all of which are characterized by short, noncontractile tails. The C(1) genome consists of a linear double-stranded DNA molecule of 16,687 nucleotides with 143-bp inverted terminal repeats. We have assigned functions to 9 of 20 putative open reading frames based on experimental substantiation or bioinformatic analysis. Their products include DNA polymerase, holin, lysin, major capsid, head-tail connector, neck appendage, and major tail proteins. Additionally, we found one intron belonging to the HNH endonuclease family interrupting the apparent lysin gene, suggesting a potential splicing event yielding a functional lytic enzyme. Examination of the C(1) DNA polymerase suggests that this phage utilizes a protein-primed mechanism of replication, which is prominent in the phi29-like members of Podoviridae. Consistent with this evidence, we experimentally determined that terminal proteins are covalently attached to both 5' termini, despite the fact that no homology to known terminal proteins could be elucidated in any of our open reading frames. Likewise, comparative genomics revealed no close evolutionary matches, suggesting that the C(1) bacteriophage is a unique member of the Podoviridae.

Animals↗

Analysis of Drosophila yellow-B cDNA reveals a new family of proteins related to the royal jelly proteins in the honeybee and to an orphan protein in an unusual bacterium Deinococcus radiodurans.

The yellow locus in Drosophila is involved in both cuticle development and behaviour. However, the function of the encoded protein is unknown. Here we have characterised the sequence and expression pattern of a new Drosophila gene, designated yellow-B, encoding a 453-amino-acid protein that is 57% identical to Yellow. High levels of yellow-B mRNA are present in the larval-pupal stages, but the gene is also expressed in the head. Bioinformatics analysis indicates that the Drosophila genome encodes at least 7 members of the Yellow family distributed among chromosomes 2, 3, and X. The Yellow proteins are related to the Royal Jelly proteins and have no relatives in other non-insect metazoan species. Interestingly, a Yellow-like protein is encoded by the genome of a radiation tolerant bacterium, Deinococcus radiodurans.

Amino Acid Sequence↗

EST analysis of mRNAs expressed in neurula of Chinese amphioxus.

Amphioxus, a cephalochordate, is the closest living relative to the vertebrates. In order to investigate the molecular mechanisms of the early embryogenesis of amphioxus, we constructed a neurula embryo cDNA library of Chinese amphioxus (Branchiostoma belcheri tsingtauense) and generated 5235 expressed sequenced tags in the present study. The initial ESTs consisted of 638 clusters and 1855 singletons, which revealed approximately 2493 unique genes in the data set. Of these sequences, 35.52% ESTs matched to known genes, 12.76% matched to other ESTs, and 51.71% had no match to any known sequences in GenBank. Interestingly we found homologous genes related to neural development and human disease. Bioinformatic analysis showed the direct evidence that the gene homologue found only in vertebrates in previous studies also exists in the amphioxus genome. This study provides a preliminary view of the gene information involved in the development of neurula embryos of Chinese amphioxus and helps our understanding of vertebrate evolution at gene level.

Animals↗

Two families with familial amyotrophic lateral sclerosis are linked to a novel locus on chromosome 16q.

Amyotrophic lateral sclerosis (ALS) is a fatal adult-onset disease in which motor neurons in the brain and spinal cord degenerate by largely unknown mechanisms. ALS is familial (FALS) in 10% of cases, and the inheritance is usually dominant, with variable penetrance. Mutations in copper/zinc super oxide dismutase (SOD1) are found in 20% of familial and 3% of sporadic ALS cases. Five families with ALS and frontotemporal dementia (ALS-FTD) are linked to 9q21, whereas one family with pure ALS is linked to 18q21. We identified two large European families with ALS without SOD1 mutations or linkage to known FALS loci and conducted a genomewide linkage screen using 400 microsatellite markers. In both families, two-point LOD scores >1 and a haplotype segregating with disease were demonstrated only across regions of chromosome 16. Subsequent fine mapping in family 1 gave a maximum two-point LOD score of 3.62 at D16S3137 and a three-point LOD score of 3.85 for markers D16S415 and D16S3137. Haplotype analysis revealed no recombination > approximately 30 cM, (flanking markers at D16S3075 and D16S3112). The maximum two-point LOD score for family 2 was 1.84 at D16S415, and the three-point LOD score was 2.10 for markers D16S419 and D16S415. Definite recombination occurred in several individuals, which narrowed the shared haplotype in affected individuals to a 10.1-cM region (flanking markers: D16S3396 and D16S3112). The region shared by both families on chromosome 16q12 corresponds to approximately 4.5 Mb on the Marshfield map. Bioinformatic analysis of the region has identified 18 known genes and 70 predicted genes in this region, and sequencing of candidate genes has now begun.

Adult↗

Design of peptide mimetics of HIV-1 gp120 for prevention and therapy of HIV disease.

It has been reported that the C-terminus of the second conserved region (C2) of the envelope glycoprotein gp120, encompassing peptide RSANFTDNAKTIIVQLNESVEIN (NTM), is important for infectivity and neutralization of the human immunodeficiency virus type 1 (HIV-1). It was also demonstrated that human natural anti-vasoactive intestinal peptide (VIP) antibodies reactive with this gp120 region play an important role in control of HIV disease progression. The bioinformatic analysis based on the time-frequency signal processing revealed non-obvious similarities between NTM and VIP. When tested against a battery of sera from 46 AIDS patients, these peptides, in spite of a significant difference in their primary structures, showed a similar reactivity profiles (r = 0.83). Presented results point out that similarity in the periodical pattern of some physicochemical properties in primary structures of peptides plays a significant role in determination of their immunological crossreactivity. Based on these findings, we propose this bioinformatic criterion be used for design of VIP/NTM peptide mimetics for prevention and treatment of HIV disease.

Amino Acid Sequence↗

Prediction of enzyme family classes.

Classes of newly found enzyme sequences are usually determined either by biochemical analysis of eukaryotic and prokaryotic genomes or by microarray chips. These experimental methods are both time-consuming and costly. With the explosion of protein sequences entering into databanks, it is highly desirable to explore the feasibility of selectively classifying newly found enzyme sequences into their respective enzyme classes by means of an automated method. This is indeed important because knowing which family or subfamily an enzyme belongs to may help deduce its catalytic mechanism and specificity, giving clues to the relevant biological function. In this study, a bioinformatical analysis was conducted for 2640 oxidoreductases classified into 16 subclasses according to the different types of substrates they act on during the catalytic process. Although it is an extremely complicated problem and might involve the knowledge of 3-dimensional structure as well as many other physical chemistry factors, some quite promising results have been obtained indicating that the family or subfamily of an enzyme is predictable to a considerable degree by means of sequence-based approach alone if a good training dataset can be established.

Amino Acid Sequence↗

Human periodontal ligament stem cells promote oral ulcer healing in rats through modulation of TGF-&#x3b2;1/smad signaling.

BACKGROUND: Oral ulcers (OU) often present with prolonged healing, recurrent episodes, and scar formation, posing challenges for clinical management. Human periodontal ligament stem cells (hPDLSCs) have shown potential in oral tissue repair, but further research is needed to clarify their mechanism of action in OU healing. This study aims to elucidate the molecular mechanisms by which hPDLSCs promote oral ulcer healing. METHOD: To identify key regulatory genes, the OU-associated microarray dataset GSE37265 was integrated with hPDLSC genomic data for differential expression analysis. Subsequently, Weighted Gene Co-expression Network Analysis (WGCNA) was used to identify functional modules associated with OU healing. In vivo, hPDLSCs were locally administered into a rat ulcer model, and therapeutic efficacy was assessed by ulcer closure rates and histological evaluation (HE and Masson's trichrome staining). Furthermore, RNA-sequencing (RNA-seq) was performed on oral mucosal tissues to delineate the underlying molecular landscape and critical signaling pathways. The involvement of the TGF-&#x3b2; signaling pathway was confirmed by real-time quantitative PCR (RT-qPCR) and Western blotting (WB) analyses. RESULTS: Bioinformatics analysis identified 92 key genes in hPDLSCs-mediated treatment of OU, highlighting the central role of the TGF-&#x3b2;1/Smad pathway. As shown by the animal studies, hPDLSCs therapy increased the healing rate to 97% by day 8 (vs. 70% in the model). Furthermore, the therapy significantly reduced inflammatory cell infiltration and abnormal collagen deposition while promoting regular collagen arrangement. Transcriptomic and molecular experiments further showed that hPDLSCs simultaneously inhibit TGF-&#x3b2;1/Smad and extracellular signal-regulated kinase (ERK) signaling pathways, thereby alleviating inflammatory responses and suppressing mucosal fibrosis. CONCLUSION: In this study, we reveal a novel role for hPDLSCs in promoting oral ulcer healing. The findings indicate that hPDLSCs suppress inflammation and fibrosis via the TGF-&#x3b2;1/Smad pathway, offering a promising therapeutic strategy for OU and other fibrotic conditions.

TGF-&#x3b2;1↗

Virulence gene identification by differential fluorescence induction analysis of Staphylococcus aureus gene expression during infection-simulating culture.

We have employed a strategy utilizing differential fluorescence induction (DFI) in an effort to identify Staphylococcus aureus genes whose products can be targeted for antimicrobial drug development. DFI allows identification of promoters preferentially active under given growth conditions on the basis of their ability to drive expression of a promoterless green fluorescent protein gene (gfp). A plasmid-based promoter trap library was constructed of 200- to 1,000-bp fragments of S. aureus genomic DNA fused to gfp, and clones with active promoters were isolated under seven different in vitro growth conditions simulating infection. Six thousand two hundred sixty-seven clones with active promoters were screened to identify those that exhibited differential promoter activity. Bioinformatic analysis allowed the identification of 42 unique operons, containing a total of 61 genes, immediately downstream of the differentially active putative promoters. Replacement mutations were generated for most of these operons, and the abilities of the resulting mutants to cause infection were assessed in two different murine infection models. Approximately 40% of the mutants were attenuated in at least one infection model.

Abscess↗

Transcription analysis of the Bacillus subtilis PucR regulon and identification of a cis-acting sequence required for PucR-regulated expression of genes involved in purine catabolism.

The PucR protein of Bacillus subtilis has previously been suggested to regulate the expression of 15 genes, pucABCDE, pucFG, pucH, pucI, pucJKLM, pucR, and gde, all of which encode proteins involved in purine catabolism. When cells are grown under nitrogen-limiting conditions, the expression of these genes is induced and intermediary compounds of the purine catabolic pathway affect this expression. By using pucR deletion mutants, we have found that PucR induces the expression of pucFG, pucH, pucI, pucJKLM, and gde while it represses the expression of pucR and pucABCDE. Deletions in the promoters of the five induced operons and genes combined with bioinformatic analysis suggested a conserved upstream activating sequence, 5'-WWWCNTTGGTTAA-3', now named the PucR box. Potential PucR boxes overlapping the -35 and -10 regions of the pucABCDE promoter and located downstream of the pucR transcription start point were also found. The positions of these PucR boxes are consistent with PucR acting as a negative regulator of pucABCDE and pucR expression. Site-directed mutations in the PucR box upstream of pucH and pucI identified positions that are essential for the induction of pucH and pucI expression, respectively. Mutants with decreased pucH or increased pucR expression obtained from a library of clones containing random mutations in the pucH-to-pucR intercistronic region all contained mutations in or near the PucR box. The induction of pucR expression under nitrogen-limiting conditions was found to be mediated by the global nitrogen-regulatory protein TnrA. In other gram-positive bacteria, we have found open reading frames that encode proteins similar to PucR located next to other open reading frames encoding proteins with similarity to purine catabolic enzymes. Hence, the PucR homologues are likely to exert the same function in other gram-positive bacteria as PucR does in B. subtilis.

Bacillus subtilis↗