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Biomedical subjects

Jie Li

Publications and source records attributed to Jie Li.

At least 37 records · Page 2Linked to original sources

Proteomic insights into platelet dysregulation and pathogenic mechanisms of chronic thromboembolic pulmonary hypertension.

BACKGROUND: Undissolved thrombus blocks the pulmonary arteries in chronic thromboembolic pulmonary hypertension (CTEPH), a potentially fatal illness that raises pulmonary resistance, causes right heart failure, and even results in death. Although platelets are linked to vascular dysfunction and thrombus formation, it is yet unknown what precise proteome alterations and mechanistic roles they play in CTEPH. METHODS: We extracted platelet-rich plasma from peripheral blood and separated the plasma to obtain enriched platelet pellet (EPP). Quantitative proteomics was used to examine EPP from CTEPH patients and healthy controls using mass spectrometry. The relationship between protein levels and clinical markers of right heart function was examined. Platelet activity, morphology, and interactions with other blood components were evaluated using transmission electron microscopy, immunofluorescence, and flow cytometry. RESULTS: The proteomic investigation found that 179 proteins were differentially expressed in CTEPH patients. The analysis revealed that these proteins were involved in crucial processes such as complement and coagulation cascades, phagosome, and neutrophil extracellular trap (NET) formation. Elevated proteins, specifically NOX2, PAD4, ITGB2, and HMGB1, have been associated to platelet-neutrophil aggregates and NET formation. In addition, enhanced P-selectin expression in platelets and plasma confirmed greater platelet activation in CTEPH patients. Notably, PAD4 and NOX2 levels showed a substantial correlation with hemodynamic parameters and right heart dysfunction. MPO-DNA, a NET marker associated with P-selectin and ITGB2 expression, was discovered in higher concentrations in CTEPH patients' plasmas. CONCLUSION: Platelet aggregation and activation in CTEPH encourage the formation of NETs, which advances the disease and prolongs thrombus. Right heart insufficiency and hemodynamic markers had a strong correlation with PAD4 and NOX2 levels, indicating that these biomarkers may be employed to assess the severity and prognosis of CTEPH disease and offer a fresh approach to targeted treatment. The results highlight the need for additional study to elucidate platelet-mediated pathways and create therapies for CTEPH that target platelets.

Humans↗

Proteomic signatures and predictive modeling of cadmium-associated anxiety in middle-aged and elderly populations: an environmental exposure association study.

BACKGROUND: Emerging evidence implicates environmental contaminants such as cadmium (Cd) as modifiable risk factors for anxiety. Despite growing recognition of heavy metal toxicity in neuropsychiatric disorders, the molecular mechanisms linking environmental exposure to anxiety pathogenesis remain poorly understood. METHODS: Based on the established cohort of individuals with cognitive impairment in cadmium-contaminated areas, this cross-sectional association study enrolled 50 middle-aged and elderly hospitalized patients from these regions, adhering to the STROBE guidelines. Blood concentrations of cadmium (Cd), lead (Pb), and mercury (Hg) were analyzed in relation to anxiety severity assessed via the Hamilton Anxiety Rating Scale (HAMA). Plasma proteomic profiling was performed using data-independent acquisition (DIA) quantitative technology with an LC-MS/MS platform (timsTOF Pro, Bruker Daltonics), systematically characterizing 2,531 proteins across all samples. Machine learning techniques, specifically XGBoost and LASSO, were employed to identify biomarkers that were subsequently validated through mediation analysis and animal experiments, allowing for the screening of key protein signatures. Finally, clinical variables were integrated to construct a comprehensive model, which was then thoroughly evaluated. RESULTS: Anxious individuals exhibited significantly higher blood Cd levels than controls (&#x3b2;&#x2009;=&#x2009;0.50, 95% CI: 0.07-0.93, p&#x2009;<&#x2009;0.01), with anxiety positively correlating with depression (r&#x2009;=&#x2009;0.62, p&#x2009;=&#x2009;0.003) and inversely with ApoE3 genotype prevalence. Proteomics identified 120 differentially expressed proteins in anxious patients, enriched in oxidative phosphorylation and neurodegenerative pathways. CCDC126 emerged as a cadmium-associated biomarker, validated in rat models exposed to Cd. Combining CCDC126, blood Cd, Pb, and hypertension, a clinical prediction model achieved robust discrimination (AUC&#x2009;=&#x2009;0.80, validation cohort). CONCLUSIONS: This first integrative environmental-proteomic study highlights cadmium's synergistic role in anxiety pathophysiology and psychiatric comorbidity. The predictive model offers translatable potential for early risk stratification, while CCDC126 provides mechanistic insights for targeted interventions in populations exposed to environmental pollutants.

Cadmium↗

The Role of Polo-Like Kinase 1 (PLK1) O-GlcNAcylation in Mitosis.

Polo-like kinase 1 (PLK1) is a crucial mitotic kinase that is implicated in various aspects of cell cycle. Many post-translational modifications have been identified on PLK1 to regulate its activation, stability, and localization. PLK1 has been shown previously to colocalize with the O-linked &#x3b2;-N-acetylglucosamine (O-GlcNAc) transferase (OGT), and OGT regulates PLK1 stability. In our recent work, we show that PLK1 is O-GlcNAcylated by click chemistry. Using stepped collisional energy/higher energy collision dissociation mass spectrometry, we mapped the PLK1 O-GlcNAc site to be T291. We further utilized fluorescent activated cell sorting and time-lapse microscopy to assess the mitotic defects of PLK1 O-GlcNAc mutants. In vivo studies in mouse xenograft demonstrated that it promoted uterine cancer tumorigenesis. In this chapter, we delineate the methodologies we used in studying PLK1 O-GlcNAcylation, including click chemistry, stepped collisional energy/higher energy collision dissociation mass spectrometry, fluorescent activated cell sorting, time-lapse microscopy, and mouse xenograft assays.

Polo-Like Kinase 1↗

Decoding the trajectory of antibiotic resistance genes in saline and alkaline soils: Insights from different fertilization regimes.

The soil salinity and alkalinity play an important role in the occurrence and proliferation of antibiotic resistance genes (ARGs). Yet, little is known the underlying mechanism by which soil salinity and alkalinity affect antibiotic resistance evolution. Here we investigated the ARGs variation in soil salinity and alkalinity environments created by different fertilization, and explored the biological mechanisms that salinity and alkalinity alter the evolutionary paradigm of antibiotic resistance. The results showed the soil treated by organic fertilizer exhibited a low salinity, neutral level (TSD 239.20 &#x3bc;S/cm, pH 7.17). The ARG abundance in the OF treatment was the highest, keeping an average of 67.83 TPM. Beside the effect of direct input of organic fertilizer at the beginning, it was important to note that, ARGs abundance during planting showed significant correlations with pH and electric conductivity. We observed that changes in microbial survival strategies under different salinity and alkalinity conditions further affected ARG hosts abundance. Indoor experiments demonstrated that there was a survival trade-off between the growth of resistant bacteria and the evolution of antibiotic resistance in salinity and alkalinity environments. Meta-genomic and Meta-transcriptomic analysis consistently demonstrated bacterial antibiotic resistance was primarily associated with pyruvate, energy and lipid metabolic pathways. The functional gene related to salinity and alkalinity, like cysH, cysK, plsB and plsC showed negative correlations with MDR. Prokaryotic transcription assays validated these relations. This study well explains the prevalence of soil ARGs after different fertilization regimes and will give a deeper understanding for the effect of soil salinity and alkalinity on antibiotic resistance evolution.

Soil↗

Is any link between inflammation and coronary artery ectasia?

Coronary artery ectasia (CAE) is well-recognized, angiographic finding of abnormal coronary dilatation, and detected in 0.3-5.3% of angiographic studies. The gold standard for diagnosis this type of aneurysm is coronary angiography, which provides information about the size, sample, location and number of aneurysms. Despite growing prevalence in recent years, controversy still exists as to the pathogenetic mechanisms that underlie this entity. An increased incidence of CAE has been reported in several disorders. Examples include atherosclerotic vascular disease, heterozygous familial hypercholesterolemia, usage of substances including herbicide spray, acetylcholinesterase inhibitors and nitrates, previous arterial balloon angioplasty, polyarteritis nodosa and Kawasaki syndrome. In addition, possible factors contributing to CAE are imbalance between matrix metalloproteinase and tissue inhibitor of metalloproteinase, angiotensin converting enzyme genotype, elevated homocysteine levels, cocaine user, smoking, vascular trauma, nitrate use and diabetes. Emerging investigations have pinpointed inflammation as a central process in all stages of atherosclerosis. This inflammatory process culminates in acute thrombotic complications and clinical events, which is involved in different clinical settings of atherosclerotic diseases. Recent data have also showed that CAE is associated with inflammatory response presented as elevated inflammatory cytokines and C-reactive protein. Accordingly, more complete understanding of the pro- and anti-inflammatory circuits that operate during CAE in particular may foster the development of novel therapeutic approaches.

Aged↗

VAMP8/endobrevin as a general vesicular SNARE for regulated exocytosis of the exocrine system.

The molecular mechanism governing the regulated secretion of most exocrine tissues remains elusive, although VAMP8/endobrevin has recently been shown to be the major vesicular SNARE (v-SNARE) of zymogen granules of pancreatic exocrine acinar cells. In this article, we have characterized the role of VAMP8 in the entire exocrine system. Immunohistochemical studies showed that VAMP8 is expressed in all examined exocrine tissues such as salivary glands, lacrimal (tear) glands, sweat glands, sebaceous glands, mammary glands, and the prostate. Severe anomalies were observed in the salivary and lacrimal glands of VAMP8-null mice. Mutant salivary glands accumulated amylase and carbonic anhydrase VI. Electron microscopy revealed an accumulation of secretory granules in the acinar cells of mutant parotid and lacrimal glands. Pilocarpine-stimulated secretion of saliva proteins was compromised in the absence of VAMP8. Protein aggregates were observed in mutant lacrimal glands. VAMP8 may interact with syntaxin 4 and SNAP-23. These results suggest that VAMP8 may act as a v-SNARE for regulated secretion of the entire exocrine system.

Animals↗

Statins may be beneficial for patients with slow coronary flow syndrome due to its anti-inflammatory property.

The phenomenon of slow progression of angiographic contrast in the coronary arteries in the absence of stenosis in the epicardial vessels in some patients presenting with chest pain has been recently called as slow coronary flow syndrome because the underlying pathophysiological mechanisms as well as therapeutics of this unique phenomenon is less well understood. Although this phenomenon was first reported on in 1972 by Tambe, few studies have focused on the etiology of this unique angiographic finding since that time. Several hypotheses have been poised to elucidate this phenomenon, including a form of early phase of atherosclerosis, small vessel dysfunction, Hagen-Poiseuille's equation model, imbalance between vasoconstrictor and vasodilatory factors, and platelet function disorder. During the last several years there has been arisen the most interesting concept of "atherosclerosis as a inflammation disease", which is involving the different entities of coronary artery disease covering slow coronary flow syndrome. The angiographic finding appeared as slow flow is an important clinical entity because it may be the cause of angina at rest or during exercise, acute myocardial infarction, and hypertension. Despite the good prognosis, patients complained commonly of persistent uncomfortable chest, which can significantly impair quality of life. There is no effective therapy for patients with slow coronary flow syndrome up to now. Statins have been showed the important benefits for the large populations of individuals at high risk of coronary artery disease. In addition to lowering lipid profile, statins have pleiotropic effects on improving vascular function. Increasing evidence, suggests that reduction of cardiovascular events conferred by statins relates not only to cholesterol lowering but also to direct effects on endothelium function as well as anti-thrombotic and anti-inflammatory actions. Accordingly, we hypotheses that these pleiotropic effects of statin may be beneficial for patients with slow coronary flow syndrome due to its pharmacological basis.

Anti-Inflammatory Agents, Non-Steroidal↗

The binding of FKBP23 to BiP modulates BiP's ATPase activity with its PPIase activity.

Peptidyl-prolyl cis-trans-isomerases (PPIases) are enzymes that can cis-trans-isomerize a Xaa-Pro peptide bond. Three families of PPIases are known: cyclophilins, FKBPs, and parvulins. The physiological functions of the PPIases are only poorly understood. In previous work, we reported that the mouse FK506-binding protein 23 (mFKBP23), which comprises an N-terminal PPIase domain and a C-terminal domain with Ca(2+)-binding sites, binds to mBiP in the endoplasmic reticulum (ER) and this binding is affected by the Ca(2+) concentration. In this study, we demonstrate the ability of mFKBP23 to modulate the ATPase activity of BiP, and that the bound mFKBP23, but not the free mFKBP23, can suppress the ATPase activity of mBiP through its PPIase activity.

Adenosine Triphosphatases↗

Stability of and inflammatory response to silicon coated with a fluoroalkyl self-assembled monolayer in the central nervous system.

A self-assembled monolayer (SAM) of fluoroalkyl silane (FAS) (CF(3)(CF(2))(5)(CH(2))(2)SiCl(3)) was deposited on the surface of silicon wafers, aiming to enhance its stability and to reduce the inflammatory response in the central nervous system. Following implantation of the FAS SAM coated silicon in rat brains, the FAS SAM coating failed to reduce the inflammatory response of silicon, because it could not prevent the corrosion of the underlying silicon. The corrosion was hindered for the initial 10 days by the FAS SAM coating, but there was nearly no difference when compared to the uncoated silicon when the implantation periods were extended to 28 and 90 days. The FAS SAM coating was completely removed within 28 and 90 days. Meanwhile, on all the extracted uncoated and FAS SAM coated silicon wafers, there were proteinaceous substances deposited on the surfaces, and the amount of the deposits increased with exposure time.

Animals↗

Correlates of lifetime suicide attempts among individuals with affective disorders in a Chinese rural community.

The aim of this study was to compare the demographic and clinical characteristics of individuals with affective disorders who had attempted suicide at some time in their lives and those who had not made a suicide attempt. In a Chinese rural community, individuals with suicide attempt (N = 30) and those without suicide attempt (N = 166) were assessed with Present State Examination (PSE). Attempters had a significantly higher level of family economic status, higher rate of lifetime depressed mood and hopelessness, and delusions than nonattempters. The logistic regression models also indicated that depressed mood and hopelessness were the most important predictors of suicide attempts. No significant difference in treatment condition was found between attempters and non-attempters. Early identification and interventions focusing on reducing depressed mood, hopelessness, and controlling psychotic symptoms may be helpful in reducing the risk of suicide attempts among individuals with affective disorders residing in the community.

Adult↗

RSS made easy: a basic guide for librarians.

Really Simple Syndication (RSS) uses extensive markup language (XML) to constantly scan the content of Web sites for updates, which will then be delivered to subscribers' desktops or mobile devices through an RSS feed. RSS helps professionals stay current while reducing workloads. Librarians need to get familiar with RSS to educate their users, to stay current in information technology, and to generate and disseminate selected information to target user groups. doi:10.1300/J115v26n01_04.

Access to Information↗

Production of a novel recombinant Drosophila melanogaster acetylcholinesterase for detection of organophosphate and carbamate insecticide residues.

A novel recombinant Drosophila melanogaster acetylcholinesterase (R-DmAChE) produced in Pichia pastoris was first reported in this study. We cloned the DmAChE cDNA by reverse transcription PCR with removal of the signal for glycosylphosphatidylinositol (GPI) anchor attachment and the endogenous signal peptide coding sequence, and inserted it into P. pastoris vector pPIC9K under control of the alcohol oxidase gene AOX1 promoter (5'AOX1). The expression cassette of AChE cDNA was then introduced into methylotrophic yeast GS115 and several recombinant strains expressing R-DmAChE were obtained. The secreted R-DmAChE showed high stability in neutral phosphate buffer at 4 degrees C, and its kinetic parameters were identical to those of the native DmAChE. The bimolecular rate constants of R-DmAChE to dichlorvos, aldicarb and carbaryl were ranging from three to six times higher than of native DmAChE. Within six insecticides, the R-DmAChE was more sensitive than EeAChE, NbAChE and HuAChE. For 10 widely used insecticides, the IC50 values to the R-DmAChE were much lower than those to AChEs commonly used in China. With the R-DmAChE-based assay, samples spiked with three concentrations of pesticides caused enzymatic activity inhibition with R.S.D. of 0-13.7%. These results suggest that the R-DmAChE can be useful for detection of organophosphate and carbamate insecticide residues.

Acetylcholinesterase↗

The cytoplasmic tail of the severe acute respiratory syndrome coronavirus spike protein contains a novel endoplasmic reticulum retrieval signal that binds COPI and promotes interaction with membrane protein.

Like other coronaviruses, severe acute respiratory syndrome coronavirus (SARS CoV) assembles at and buds into the lumen of the endoplasmic reticulum (ER)-Golgi intermediate compartment (ERGIC). Accumulation of the viral envelope proteins at this compartment is a prerequisite for virus assembly. Previously, we reported the identification of a dibasic motif (KxHxx) in the cytoplasmic tail of the SARS CoV spike (S) protein that was similar to a canonical dilysine ER retrieval signal. Here we demonstrate that this motif is a novel and functional ER retrieval signal which reduced the rate of traffic of the full-length S protein through the Golgi complex. The KxHxx motif also partially retained two different reporter proteins in the ERGIC region and reduced their rates of trafficking, although the motif was less potent than the canonical dilysine signal. The dibasic motif bound the coatomer complex I (COPI) in an in vitro binding assay, suggesting that ER retrieval may contribute to the accumulation of SARS CoV S protein near the virus assembly site for interaction with other viral structural proteins. In support of this, we found that the dibasic motif on the SARS S protein was required for its localization to the ERGIC/Golgi region when coexpressed with SARS membrane (M) protein. Thus, the cycling of SARS S through the ER-Golgi system may be required for its incorporation into assembling virions in the ERGIC.

Amino Acid Motifs↗

Microglial activation as a priming event leading to paraquat-induced dopaminergic cell degeneration.

Dopaminergic cells in the substantia nigra are highly vulnerable to the neurodegenerative process of Parkinson's disease. Therefore, mechanisms that enhance their susceptibility to injury bear important implications for disease pathogenesis. Repeated injections with the herbicide paraquat cause oxidative stress and a selective loss of dopaminergic neurons in mice. In this model, the first paraquat exposure, though not sufficient to induce any neurodegeneration, predisposes neurons to damage by subsequent insults. The purpose of this study was to elucidate the mechanisms underlying this "priming" event. We found that a single paraquat exposure was followed by an increase in the number of cells with immunohistochemical, morphological and biochemical characteristics of activated microglia, including induction of NADPH oxidase. If this microglial response was inhibited by the anti-inflammatory drug minocycline, subsequent exposures to the herbicide failed to cause oxidative stress and neurodegeneration. On the other hand, if microglial activation was induced by pre-treatment with lipopolysaccharide, a single paraquat exposure became capable of triggering a loss of dopaminergic neurons. Finally, mutant mice lacking functional NADPH oxidase were spared from neurodegeneration caused by repeated paraquat exposures. Data indicate that microglial activation and consequent induction of NADPH oxidase may act as risk factors for Parkinson's disease by increasing the vulnerability of dopaminergic cells to toxic injury.

Animals↗

Quantitative structure-retention relationship studies with immobilized artificial membrane chromatography II: partial least squares regression.

We aimed to establish quantitative structure-retention relationship (QSRR) with immobilized artificial membrane (IAM) chromatography using easily understood and obtained physicochemical molecular descriptors and to elucidate which descriptors are critical to affect the interaction process between solutes and immobilized phospholipid membranes. The retention indices (logk(IAM)) of 55 structurally diverse drugs were determined on an immobilized artificial membrane column (IAM.PC.DD2) directly or obtained by extrapolation method for highly hydrophobic compounds. Ten simple physicochemical property descriptors (clogP, rings, rotatory bond, hydro-bond counting, etc.) of these drugs were collected and used to establish QSRR and predict the retention data by partial least squares regression (PLSR). Five descriptors, clogP, rotatory bond (RotB), rings, molecular weight (MW) and total surface area (TSA), were reserved by using the Variable Importance for Projection (VIP) values as criterion to build the final PLSR model. An external test set was employed to verify the QSRR based on the training set with the five variables, and QSRR by PLSR exhibited a satisfying predictive ability with R(p)=0.902 and RMSE(p)=0.400. Comparison of coefficients of centered and scaled variables by PLSR demonstrated that, for the descriptors studied, clogP and TSA have the most significant positive effect but the rotatable bond has significant negative effect on drug IAM chromatographic retention.

Chromatography, High Pressure Liquid↗

Enhanced G-protein coupled receptors-mediated contraction and reduced endothelium-dependent relaxation in hypertension.

The present study was designed to demonstrate a hypothesis that some G-protein coupled receptors are up-regulated and a dysfunction of endothelium occurs in hypertension. The arteries from hypertensive patients and spontaneously hypertensive rats (SHR) were tested. An in vitro myograph system was used to obtain concentration-contraction curves mediated by endothelin ET(A), endothelin ET(B), 5-hydroxytryptamine 2A (5-HT2A)-receptors and alpha1-adrenoceptors in the arterial segments. In hypertensive patients, the maximum contractions (Emax) induced by endothelin ET(B), endothelin ET(A) and 5-HT receptors were significantly increased with elevated pEC50 values, while a significantly leftward shift of alpha1-adrenoceptor-mediated contraction was seen. Similar results were obtained in SHR. Specific antagonists for 5-HT2A receptors or alpha1-adrenoceptors rightward shifted the concentration-contractile curves induced by 5-HT or noradrenaline, while the Emax were not significantly altered, suggesting that the contractions were mediated by 5-HT2A receptors and alpha1-adrenoceptors, respectively. Endothelium-dependent maximum relaxation (Rmax) in the arterial segments induced by acetylcholine was significantly decreased in both hypertensive patients and SHR. In addition, nitric oxide- and endothelium-derived hyperpolarizing factor-mediated dilatations were decreased significantly and the arterial endothelial cells were in part lost in SHR. In conclusion, endothelin ET(B), endothelin ET(A), 5-HT2A receptor- and alpha-adrenoceptor-mediated contractions were increased in hypertension, while the endothelium and its functions were damaged.

Adrenergic alpha-Agonists↗

The Arabidopsis histidine phosphotransfer proteins are redundant positive regulators of cytokinin signaling.

Arabidopsis thaliana histidine phosphotransfer proteins (AHPs) are similar to bacterial and yeast histidine phosphotransfer proteins (HPts), which act in multistep phosphorelay signaling pathways. A phosphorelay pathway is the current model for cytokinin signaling. To assess the role of AHPs in cytokinin signaling, we isolated T-DNA insertions in the five AHP genes that are predicted to encode functional HPts and constructed multiple insertion mutants, including an ahp1,2,3,4,5 quintuple mutant. Single ahp mutants were indistinguishable from wild-type seedlings in cytokinin response assays. However, various higher-order mutants displayed reduced sensitivity to cytokinin in diverse cytokinin assays, indicating both a positive role for AHPs in cytokinin signaling and functional overlap among the AHPs. In contrast with the other four AHPs, AHP4 may play a negative role in some cytokinin responses. The quintuple ahp mutant showed various abnormalities in growth and development, including reduced fertility, increased seed size, reduced vascular development, and a shortened primary root. These data indicate that most of the AHPs are redundant, positive regulators of cytokinin signaling and affect multiple aspects of plant development.

Arabidopsis↗