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Biomedical subjects

Ling Wang

Publications and source records attributed to Ling Wang.

At least 19 recordsLinked to original sources

Genome-wide DNA methylation analysis revealed epigenetic mechanism underlying end-stage renal disease.

End-stage renal disease (ESRD) remains a major clinical challenge with high morbidity and mortality, and its molecular mechanisms, particularly those shared among diverse primary kidney diseases during progression to ESRD, have not been studied. Here we conduct a large-scale two-stage epigenome-wide association study of ESRD in two independent cohorts consisting of 704 controls and 1031 ESRD cases. We identify 52 ESRD-associated differentially methylated CpG positions (ESRD DMPs) showing consistent association between the two cohorts and across diverse kidney diseases, implicating 144 candidate genes enriched in inflammatory and immune pathways. Five of the 52 DMPs are associated with ESRD complications, and seven with renal function decline in early-stage chronic kidney disease, demonstrating their potential as prognostic biomarkers for ESRD and its complications. Our findings highlight inflammation, immune dysregulation, and renal fibrosis as shared epigenetic drivers of ESRD progression, and identify biomarkers with potential utility for risk stratification and therapeutic intervention.

Humans↗

Transcranial Alternating Current Stimulation at 40 Hz Improves Social Functioning in Children With Autism Spectrum Disorder: A Randomized Clinical Trial.

BACKGROUND: Autism spectrum disorder (ASD) lacks rapid and effective interventions for its core social difficulties. The right temporoparietal junction (rTPJ), a critical hub for social cognition, together with gamma band abnormalities implicated in ASD, provides a promising neuromodulation target. METHODS: In this randomized, double-blind, sham-controlled trial, 47 children with ASD (39 male; mean [SD] age = 8.79 [2.71] years) were assigned to receive either 21 sessions of 40-Hz high-definition transcranial alternating current stimulation (tACS) targeting the rTPJ (3 sessions/day for 7 days) or sham stimulation, with assessments conducted at baseline, postintervention (week 1), and a 3-week follow-up (week 4). The primary outcome was change in Ohio State University Autism Rating Scale-DSM-5 (OARS-5) total scores. Secondary outcomes included the Aberrant Behavior Checklist-Second Edition, Social Responsiveness Scale-Second Edition, and Short Sensory Profile. Eye-tracking metrics during Frith-Happ&#xe9; animations were exploratory measures of theory of mind (ToM)-related social cognitive processing. RESULTS: The active group demonstrated significant improvements in OARS-5 total scores at week 1 (mean difference = -1.13, 95% CI [-1.78 to -0.47], p < .001) and week 4 (mean difference = -1.47, 95% CI [-2.20 to -0.74], p < .001). Improvements in selected behavioral and sensory domains were observed. Average fixation duration during ToM animations showed a significant group &#xd7; time interaction. No serious adverse events occurred. CONCLUSIONS: These findings suggest that 40-Hz tACS targeting the rTPJ may be associated with rapid improvements in ASD symptom severity, particularly social functioning, in children with ASD, while being well tolerated. Clinical significance requires further evaluation.

Humans↗

Probiotic potential of Parabacteroides johnsonii in mitigating age-related ovarian functional decline.

The gut microbiota is increasingly recognized as a regulator of reproductive health, yet its role in ovarian aging remains unclear. Here, we combine Mendelian randomization (MR) analysis with experimental validation to investigate the causal relationship between gut microbiota and ovarian aging. MR analysis identifies four microbial taxa significantly associated with age at natural menopause. In mouse models, germ-free mice exhibit accelerated ovarian functional decline, including reduced ovarian reserve and impaired folliculogenesis. Fecal microbiota transplantation (FMT) from young donors alleviates ovarian aging phenotypes, whereas FMT from aged donors exacerbates functional decline. Metagenomic analysis reveals species-level differences between young and ovarian-aging mice, with Parabacteroides johnsonii (P. johnsonii) enriched in young mice. Administration of P. johnsonii to middle-aged mice improves ovarian reserve, reduces follicular atresia, enhances granulosa cell proliferation, and decreases systemic inflammation. These findings highlight a causal role of the gut microbiota in ovarian aging and support microbiota-targeted interventions as a potential strategy to preserve ovarian function.

Female↗

BRCA1-A and LIG4 complexes mediate ecDNA biogenesis and cancer drug resistance.

Extrachromosomal circular DNA (ecDNA) is frequently generated within the nucleus, contributing to genome dynamics and heterogeneity, thereby promoting cancer cell evolution and adaptation. However, the mechanisms underlying ecDNA biogenesis remain poorly understood. Here, using genome-wide CRISPR screening in human cells, we identified the BRCA1-A and the LIG4 complexes as key drivers of ecDNA production. Following DNA segmentation, the upstream BRCA1-A complex protects DNA ends from excessive resection, promoting end-joining for circularization. Conversely, the MRN complex, which mediates end resection and thus antagonizes the BRCA1-A complex, suppresses ecDNA formation. Downstream, LIG4 conservatively mediates ecDNA production by joining the free ends of the DNA fragments. Furthermore, ecDNA from patient tumors harbors junction sites with a LIG4 signature. Notably, disruption of either LIG4 or the BRCA1-A complex in cancer cells impairs ecDNA-mediated adaptation, hindering the development of resistance to both chemotherapy and targeted therapies. Together, our study reveals the roles of the LIG4 and BRCA1-A complexes in ecDNA biogenesis, and uncovers therapeutic targets to block ecDNA-mediated adaptation for cancer treatment.

Humans↗

Patient-derived organoids predict responses to chemotherapy and PARP inhibitors in advanced ovarian cancer.

BACKGROUND: While tumor organoids hold promise for personalized medicine, clinical validation of epithelial ovarian cancer (EOC) organoids as predictors of therapeutic efficacy-particularly for PARP inhibitors (PARPi)-remains unestablished. METHODS: Patient-derived organoids (PDOs) were established from treatment-naive EOC specimens and characterized by H&E staining, immunohistochemistry, and whole-exome sequencing. Drug sensitivity testing (DST) was performed using carboplatin, paclitaxel, and PARPi (olaparib and niraparib). Clinical homologous recombination deficiency (HRD) status was assessed by tumor sequencing. Organoid responses were prospectively compared to patient outcomes after first-line chemotherapy (carboplatin/paclitaxel) and PARPi maintenance. RESULTS: PDOs were successfully established from 21 of 30 patients (70%) across multiple EOC subtypes and preserved the histopathological features and genomic landscapes of their corresponding primary tumors. Organoid-based DST accurately predicted responses to first-line carboplatin/paclitaxel, with a sensitivity of 100% (95% CI 62.88-100%), specificity of 66.67% (95% CI 12.53-98.23%), accuracy of 91.67% (95% CI 61.52-99.79%), AUC of 0.95 (95% CI 0.85-1.00), and Cohen's kappa of 0.75 (95% CI 0.30-1.00). In evaluating PARPi response, organoids revealed discrepancies between genomic HRD status and actual drug responses. One HRD-positive PDO was PARPi-resistant, consistent with patient non-response, while two HRR-proficient PDOs showed PARPi sensitivity and corresponding clinical benefit. CONCLUSIONS: EOC-derived PDOs provide a robust platform for predicting chemotherapy response and offer added value in assessing PARPi efficacy beyond genomic profiling. Combination of organoid-based testing with genomic analysis may improve precision treatment strategies in EOC.

Humans↗

&#x3b3;-tubulin mediates DNA double-strand break repair.

Double-strand breaks (DSBs) in DNA pose a critical threat to genomic integrity, potentially leading to the onset and progression of various diseases, including cancer. Cellular responses to such lesions entail sophisticated repair mechanisms primarily mediated by non-homologous end joining (NHEJ) and homologous recombination (HR). Interestingly, the efficient recruitment of repair proteins and completion of DSB repair likely involve complex, inter-organelle communication and coordination of cellular components. In this study, we report a role of &#x3b3;-tubulin in DSB repair. &#x3b3;-tubulin is a major microtubule nucleation factor governing microtubule dynamics. We show that &#x3b3;-tubulin is recruited to the site of DNA damage and is required for efficient DSB repair via both NHEJ and HR. Suppression of &#x3b3;-tubulin impedes DNA repair and exacerbates DNA damage accumulation. Furthermore, &#x3b3;-tubulin mediates the mobilization and formation of DNA damage foci, which serve as repair centers, thereby facilitating the recruitment of HR and NHEJ repair proteins on damaged chromatin. Finally, pharmacological inhibition of &#x3b3;-tubulin enhances the cytotoxic effect of DNA-damaging agents, consistent with the DNA repair function of &#x3b3;-tubulin, and underscoring the potential of its therapeutic intervention in cancer therapy.

DNA Breaks, Double-Stranded↗

Livin/ML-IAP as a new target for cancer treatment.

Livin is a member of the inhibitors of apoptosis protein (IAP) gene family, which encodes negative regulatory proteins that prevent cell apoptosis. Livin is selectively expressed in the most common human neoplasms and appears to be involved in tumor cell resistance to chemotherapeutic agents. Several studies in vitro and in vivo have demonstrated that down-regulation of Livin expression increases the apoptotic rate, reduces tumor growth potential and sensitized tumor cells to chemotherapeutic drugs. This review will focus on the role of this protein during cancer development and progression and will demonstrate possible targets for cancer therapy.

Adaptor Proteins, Signal Transducing↗

Simple determination of huperzine A in human plasma by liquid chromatographic-tandem mass spectrometric method.

Huperzine A is a potent, reversible acetylcholinesterase inhibitor. In the present work, a rapid and sensitive LC-MS-MS method for the determination of huperzine A in human plasma using codeine phosphate as internal standard has been developed and validated. The analyte and internal standard were extracted from plasma using ethyl acetate, chromatographed on a C(18) column (5 microm, 150 x 4.6 mm i.d.) with a mobile phase consisting of 1% formic acid-methanol (40:60, v/v), and detected using a tandem mass spectrometer with a TurboIonSpray ionization interface. The run time was only 2 min. Good linearity was achieved in the range 0.126 -25.2 ng/mL and the limit of detection in plasma was 0.064 ng/mL. The average recovery for huperzine A was 83.4% from plasma. The analytical sensitivity and accuracy of this assay is adequate for characterization of huperzine A in human plasma.

Alkaloids↗

[Construction and expression of eukaryotic coexpression plasmid containing human MUC1 gene and GM-CSF gene].

AIM: To construct an eukaryotic coexpression plasmid containing the coding region of human MUC1 tandem repeats gene and GM-CSF gene and to identify its expression in COS-7 cell. METHODS: MUC1 tandem repeats gene was obtained by synthesizing the segments. After identified by restriction endonuclease digestion analysis and DNA sequencing, MUC1 tandem repeats gene and GM-CSF gene were cloned into eukaryotic expression vector pcDNA3.1(+) to construct recombinant plasmid pcDNA3.1(+)-MUC1-GM-CSF. Then the recombinant plasmid was transfected into COS-7 cell by electroporation and the expression of target gene was detected by immunoflourescence and ELISA. RESULTS: Restriction analysis and DNA sequencing showed that the recombinant plasmid contained the coding region of human MUC1 tandem repeats gene and GM-CSF gene. The expression of MUC1 and GM-CSF was detected. CONCLUSION: The suuessful construction and expression of recombinant plasmid pcDNA3.1(+)-MUC1-GM-CSF lay a foundation for further development of DNA vaccine against breast cancer.

Animals↗

Differential cell cycle-specificity for chromosomal damage induced by merbarone and etoposide in V79 cells.

Merbarone, a topoisomerase II (topo II) inhibitor which, in contrast to etoposide, does not stabilize topo II-DNA cleavable complexes, was previously shown to be a potent clastogen in vitro and in vivo. To investigate the possible mechanisms, we compared the cell cycle-specificity of the clastogenic effects of merbarone and etoposide in V79 cells. Using flow cytometry and BrdU labeling techniques, etoposide was shown to cause a rapid and persistent G2 delay while merbarone was shown to cause a prolonged S-phase followed by a G2 delay. To identify the stages which are susceptible to DNA damage, we performed the micronucleus (MN) assay with synchronized cells or utilized a combination of BrdU pulse labeling and the cytokinesis-blocked MN assay with non-synchronized cells. Treatment of M phase cells with either agent did not result in increased MN formation. Etoposide but not merbarone caused a significant increase in MN when cells were treated during G2 phase. When treated during S-phase, both chemicals induced highly significant increases in MN. However, the relative proportion of MN induced by merbarone was substantially higher than that induced by etoposide. Both chemicals also caused significant increases in MN in cells that were treated during G1 phase. To confirm the observations in the MN assay, first division metaphases were evaluated in the chromosome aberration assay. The chromosomes of cells treated with merbarone and etoposide showed increased frequencies of both chromatid- and chromosome-type of aberrations. Our findings indicate that while etoposide causes DNA damage more evenly throughout the G1, S and G2 phases of the cell cycle, an outcome which may be closely associated with topo II-mediated DNA strand cleavage, merbarone induces DNA breakage primarily during S-phase, an effect which is likely due to the stalling of replication forks by inhibition of topo II activity.

Animals↗

Analysis of bacteria degradation products of methyl parathion by liquid chromatography/electrospray time-of-flight mass spectrometry and gas chromatography/mass spectrometry.

The biodegradation of the organophosphorus insecticide methyl parathion (MP) in aqueous environment by bacteria isolated from river sediment has been studied. Two species of bacteria which show strong MP degradation ability are identified as Shewanella and Vibrio parahaemolyticus. The biodegradation of MP proceeded rapidly with the formation of a series of intermediate products, which were analyzed using a combination of GC/MS and HPLC/ESI-TOFMS techniques. The major products tentatively identified include a series of reduced products of MP. Results demonstrate that the coupling of TOFMS to HPLC enhances further the capability of LC-MS in the identification of polar organic species in complex environmental samples. Degradation pathways leading to the formation of these products are proposed which involves first the reduction of nitro to amino group in MP, followed by combination with some intrinsic matters of bacteria. The mechanism and products from biodegradation are quite different from those of photocatalytic process for which the main intermediates included methyl paraoxon and 4-nitrophenol.

Biotransformation↗

Novel role of the human alveolar epithelium in regulating intra-alveolar coagulation.

Intra-alveolar fibrin deposition is a common response to localized and diffuse lung infection and acute lung injury (ALI). We hypothesized that the alveolar epithelium modulates intra-alveolar fibrin deposition through activation of protein C. Our objectives [corrected] were to determine whether components of the protein C activation pathway are present in the alveolar compartment in ALI and whether alveolar epithelium is a potential source. In patients with ALI, pulmonary edema fluid levels of endothelial protein C receptor (EPCR) were higher than plasma, suggesting a source in the lung. To determine whether alveolar epithelial cells are a potential source, protein C activation by A549, small airway epithelial, and primary human alveolar epithelial type II cells was measured. All three cell types express thrombomodulin (TM) and EPCR, and activate protein C on the cell surface. Activation of protein C was inhibited by cytomix (TNF-alpha, IL-1beta, and IFN-gamma). Release of EPCR and TM into the conditioned medium was inhibited by the metalloproteinase inhibitors tumor necrosis factor protease inhibitor (TAPI) and GM6001, indicating that the shedding of EPCR and TM from the alveolar epithelium is mediated by a metalloproteinase. These findings provide new evidence that the alveolar epithelium can modulate the protein C pathway and thus could be an important determinant of alveolar fibrin deposition. Local fibrin deposition may be a fundamental mechanism for the lung to localize and confine injury, thus limiting the risk of dissemination of injury or infection to the systemic circulation.

Adult↗

Effects of aspirin on atherosclerosis and the cyclooxygenase-2 expression in atherosclerotic rabbits.

BACKGROUND: Atherosclerosis is a complex vascular inflammatory disease. Aspirin is a mainstay in the prevention of vascular complications of atherosclerosis. In this study, the effectiveness of aspirin in suppressing atherosclerosis and the inflammation process was evaluated in rabbits fed with a high fat diet. METHODS: Eighteen male New Zealand rabbits were randomly divided into 3 groups: control group, untreated cholesterol-fed group, aspirin treated cholesterol-fed group, which were fed for 12 weeks. After 12 weeks, the aorta was harvested for pathologic morphology observation. Immunohistochemical analysis of cyclooxygenase-2 (COX-2), macrophage and vascular smooth muscle cell (VSMC) was performed. The statistical analysis was performed by the statistical program SPSS10.0. RESULTS: The aorta plaque/intima size (P/I) by pathologic morphology observation was 0%, (59.6 +/- 13.7)% and (36.3 +/- 16.5)% in the control, untreated cholesterol-fed group and aspirin treated group, respectively. The maximum plaque thickness, the degree of artery stenosis and the proportion of the intimal circumference occupied by atheroma of the 3 groups were significantly different from each other (P < 0.01). The expression of COX-2 and macrophage in plaque of the aspirin treated group were decreased compared with that in untreated cholesterol-fed group. However, no difference was found in the expression of VSMC between the aspirin treated and the untreated cholesterol-fed group. CONCLUSION: The mechanism of atherosclerosis suppression by aspirin in cholesterol-fed rabbits is related to the inhibition of COX-2 expression together with the reduced inflammation followed by, but not related to the hypolipidemic effects.

Animals↗

Rapamycin is efficacious against primary effusion lymphoma (PEL) cell lines in vivo by inhibiting autocrine signaling.

The antitumor potency of the mTOR inhibitor rapamycin (sirolimus) is the subject of intense investigations. Primary effusion lymphoma (PEL) appears as an AIDS-defining lymphoma and like Kaposi sarcoma has been linked to Kaposi sarcoma-associated herpesvirus (KSHV). We find that (1) rapamycin is efficacious against PEL in culture and in a murine xenograft model; (2) mTOR, its activator Akt, and its target p70S6 kinase are phosphorylated in PEL; (3) rapamycin inhibits mTOR signaling as determined by S6 phosphorylation; (4) KSHV transcription is unaffected; (5) inhibition of IL-10 signaling correlates with drug sensitivity; and (6) addition of exogenous IL-10 or IL-6 can reverse the rapamycin growth arrest. This validates sirolimus as a new treatment option for PEL.

Animals↗

Expression and regulatory role of GAIP-interacting protein GIPC in pancreatic adenocarcinoma.

Regulator of G-protein signaling-GAIP-interacting protein COOH terminus (GIPC) is involved in protein trafficking, endocytosis, and receptor clustering and is associated with insulin-like growth factor I receptor (IGF-IR), a receptor important for proliferation and anchorage-independent growth. Here, we described GIPC expression in different human pancreatic adenocarcinoma (PCA) cell lines and we examined the role of GIPC in the regulation of IGF-IR protein levels in PCA. Interestingly, inhibition of GIPC expression by RNA interference led to reduced IGF-IR protein levels and a subsequent decrease in proliferation of PCA cells. We also determined that the PDZ domain of GIPC is essential for the post-translational regulation and the binding of IGF-IR. The importance of GIPC in pancreatic cancer development and progression is supported by tissue microarray data of 300 pancreatic cancer specimens where GIPC is highly expressed in PCA. Taken together, our data suggest that GIPC is a central molecule for the stability of IGF-IR and could be a target for future therapy.

Adaptor Proteins, Signal Transducing↗

Kinetic and mass spectrometric analysis of p300 histone acetyltransferase domain autoacetylation.

Acetylation of proteins by p300 histone acetyltransferase plays a critical role in the regulation of gene expression. The prior discovery of an autoacetylated regulatory loop in the p300 histone acetyltransferase (HAT) domain prompted us to further explore the mechanisms of p300 autoacetylation. Here we have described a kinetic and mass spectrometric analysis of p300 HAT autoacetylation. The rate of p300 HAT autoacetylation was approximately fourth order with respect to p300 HAT domain concentration and thus appeared to be a highly cooperative process. By showing that a catalytically defective p300 HAT domain could be efficiently acetylated by active p300 HAT, we deduced that autoacetylation occurs primarily by an intermolecular mechanism. This was further confirmed using a semisynthetic biotinylated p300 HAT domain that could be physically separated from the catalytically defective p300 HAT by avidin affinity chromatography. Autoacetylation catalyzed by p300 HAT was approximately 1000-fold more efficient than PCAF (p300/CREB-binding protein-associated factor)-mediated acetylation of catalytically defective p300 HAT. Using a novel tandem mass spectrometric approach, it was found to be possible to observe up to 17 autoacetylation events within the intact p300 regulatory loop. Kinetic analysis of the site specificity of p300 autoacetylation reveals a class of rapid events followed by a slower set of modifications. Several of these rapid autoacetylation sites correlate with an acetyltransferase-activating function based on prior mutagenesis analysis.

Acetylation↗

A biocompatible method of decorporation: bisphosphonate-modified magnetite nanoparticles to remove uranyl ions from blood.

We report on the use of bisphosphonate to functionalize Fe3O4 magnetic nanoparticles via dopamine (DA) linkage. Using tetraethyl-3-aminopropane-1,1-bisphosphonate (BP) as the functional molecule, we created a system with an Fe3O4-DA-BP nanostructure, which possesses high specificity for removing uranyl ions from water or blood. This work demonstrates that magnetic nanoparticles, combined with specific receptor-ligand interactions, promise a sensitive and rapid platform for the detection, recovery, and decorporation of metal toxins from biological environment.

Biocompatible Materials↗