Electrochemical biomimetic enzyme cascade amplification combined with target-induced DNA walker for detection of thrombin.

Fe-N-doped carbon nanomaterials (Fe-N/CMs) were designed as a novel biomimetic enzyme with excellent peroxidase-like activity to achieve high-efficient enzyme cascade catalytic amplification with the aid of glucose oxidase (GOx), which was further combined with target-induced DNA walker amplification to develop a sensitive electrochemical biosensor for thrombin detection. Impressively, massive output DNA was transformed from small amounts of target thrombin by highly effective DNA walker amplification as protein-converting strategy, which could then induce the immobilization of functionalized nanozyme on the electrode surface to achieve the high-efficient electrochemical biomimetic enzyme cascade amplification. As a result, an amplified enzyme cascade catalytic signal was measured for thrombin detection ranging from 0.01 pM to 1 nM with a low detection limit of 3 fM. Importantly, the new biomimetic enzyme cascade reaction coupled the advantages of natural enzyme and nanozyme, which paved an avenue to construct varied artificial multienzymes amplification systems for biosensing, bioanalysis, and disease diagnosis applications.

Using machine learning to predict lymph node metastasis in patients with renal cell carcinoma: A population-based study.

Background: Lymph node (LN) metastasis is strongly associated with distant metastasis of renal cell carcinoma (RCC) and indicates an adverse prognosis. Accurate LN-status prediction is essential for individualized treatment of patients with RCC and to help physicians make appropriate surgical decisions. Thus, a prediction model to assess the hazard index of LN metastasis in patients with RCC is needed. Methods: Partial data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Data of 492 individuals with RCC, collected from the Southwest Hospital in Chongqing, China, were used for external validation. Eight indicators of risk of LN metastasis were screened out. Six machine learning (ML) classifiers were established and tuned, focused on predicting LN metastasis in patients with RCC. The models were integrated with big data analytics and ML algorithms. Based on the optimal model, we developed an online risk calculator and plotted overall survival using Kaplan-Meier analysis. Results: The extreme gradient-boosting (XGB) model was superior to the other models in both internal and external trials. The area under the curve, accuracy, sensitivity, and specificity were 0.930, 0.857, 0.856, and 0.873, respectively, in the internal test and 0.958, 0.935, 0.769, and 0.944, respectively, in the external test. These parameters show that XGB has an excellent ability for clinical application. The survival analysis showed that patients with predicted N1 tumors had significantly shorter survival (p < 0.0001). Conclusion: Our study shows that integrating ML algorithms and clinical data can effectively predict LN metastasis in patients with confirmed RCC. Subsequently, a freely available online calculator (https://xinglinyi.shinyapps.io/20221004-app/) was built, based on the XGB model.

Highly Efficient Electrochemiluminescence Based on Luminol/MoS2 Quantum Dots@Zeolitic Imidazolate Framework-8 as an Emitter for Ultrasensitive Detection of MicroRNA.

Herein, a highly efficient electrochemiluminescence (ECL) emitter, luminol/MoS2 quantum dots@zeolitic imidazolate framework-8 (Lu/MoS2 QDs@ZIF-8), with a positive charge was prepared to construct a novel luminol-H2O2-MoS2 QD ternary ECL system for ultrasensitive detection of microRNA-21 (miRNA-21). The porous Lu/MoS2 QDs@ZIF-8 was beneficial for reducing the accessible distance between various participants in the ternary system wherein co-reaction accelerator MoS2 QDs promoted H2O2 to generate superoxide anion radicals (O2•-), which instantaneously reacted with luminol to produce robust ECL signals. Simultaneously, the positively charged Lu/MoS2 QDs@ZIF-8 facilitated the enrichment of O2•- to further improve the ECL efficiency of luminol. Impressively, compared with the traditional binary luminol-H2O2 system, the ECL efficiency of this ternary system was increased by 12.7 times. In the aid of a target-cycled and endogenous adenosine triphosphate-driven signal amplification strategy, the biosensor with Lu/MoS2 QDs@ZIF-8 as an ECL emitter achieved ultrasensitive detection for miRNA-21 with a detection limit of 14.6 aM. This work provides a promising perspective to construct a highly efficient ECL ternary system for biomolecule detection and potential disease diagnosis.

Two kinds of DNA enzyme-powered bidirectional one-dimensional DNA walking nanomachine for payload release and biosensing.

Herein, we present a target-triggered bidirectional one-dimensional (1D) DNA walking nanomachine, built from a well-designed track, which could simultaneously move two different DNA walkers to the opposite direction along the track and release payload. This track is composed of a DNA walker station (chain S3) in the middle of track for storing two kinds of DNA walker (W1 and W2), and corresponding two kinds of payload conjugated DNA stators (chain S1, S2 and S4, S5) for the moving of walker on the two flanks of chain S3 respectively. Moreover, the chain S3 also serves as a target-assisted amplification platform based on a catalytic hairpin assembly (CHA)-like strategy. In the presence of target (nucleic acid), the dynamic assembly between hairpin (HP) and S3 is triggered for multiple recycling of target and releasing of W1 and W2. Since the W1 and W2 respectively correspond to 8-17 DNAzyme and 10-23 DNAzyme, they could cleave the RNA substrates with sequence specificity to move towards two opposite directions along the track at the same time, accompanying the release of payloads. Such a 1D DNA walking nanomachine is not only could propel the walker to move in two directions respectively but also improve the locomotion efficiency compared to the traditional single-directional 1D DNA walking nanomachine with the same amounts of stators. This concept of inducing the locomotion manner change on a 1D DNA device may provide a thought to facilitate the development of DNA dynamic nanomachines and intelligent nanosensors.

Unexpected Complication of Central Venous Catheter Exchange: Catheter Fragment Migration.

Tunneled central venous catheter (TCVC) placement is often an easy and uncomplicated procedure. As such, some clinicians pay little attention to the procedure, and different complications occurred. Catheter fragment loss in major vessels is a rare but serious complication of in situ catheter exchange with few reported cases in the literature. Once catheter fragments slip into a deep vein, endovascular retrieval should be attempted, due to its high success rate and minimal associated morbidity. A 37-year-old male patient underwent replacement of his temporary catheter with TCVC through a trans-right-internal-jugular-vein approach for maintenance of dialysis. As a major unintended outcome of the operation, a catheter fragment slipped into the right internal jugular vein, then migrated and lodged in the inferior vena cava. We retrieved it with a gooseneck snare without complications. We report the case hoping to emphasize on and raise awareness of the fact that catheter fragment loss is a completely evitable complication, provided the operator follows the correct safety measures and protocols. However, if catheter fragment loss occurred, the fragment should be retrieved as soon as possible. A gooseneck snare is an ideal option for retrieving catheter fragments that have migrated into deep veins.

LIGHT deficiency aggravates cisplatin-induced acute kidney injury by upregulating mitochondrial apoptosis.

Cisplatin is widely used as a chemotherapeutic agent for treating patients with solid tumors. The most common side effect of cisplatin treatment is nephrotoxicity. Recent studies have shown that mitochondrial apoptotic pathways are involved in cisplatin-induced acute kidney injury (Cis-AKI). LIGHT, the 14th member of the tumor necrosis factor superfamily (TNFSF14), was found to induce apoptosis of certain types of tumor cells. So far, a link between LIGHT and Cis-AKI has not been reported. In this study, we observed that expression of LIGHT and its receptors HVEM and LTßR was increased in kidney tissues of mice after cisplatin treatment. LIGHT deficiency aggravated kidney injury, as evidenced by more severe tubular injury; remarkably increased levels of serum creatinine (Scr), blood urea nitrogen (BUN), and both kidney injury molecule-1 (KIM-1) and inflammatory cytokine mRNAs in renal tissues. Moreover, in the renal tissues of LIGHT KO mice, cisplatin-induced mitochondrion injury and the levels of the pro-apoptotic molecules Bax, Cytochrome C (Cyt C), cleaved caspase-3, and cleaved caspase-9 were dramatically increased; in contrast, the expression of anti-apoptotic molecule Bcl-2 was markedly reduced, compared to those in WT mice, suggesting that LIGHT deficiency accelerated cisplatin-induced mitochondrial apoptosis of renal tubular cells in these mice. Accordingly, treatment with recombinant human LIGHT (rLIGHT) was shown to alleviate cisplatin-induced kidney injury in vivo. Similar results were observed after the human renal tubular epithelial cell line HK-2 cells exposure to rLIGHT stimulation, evidenced by the reduction in the mitochondrion dysfunction (as confirmed by the significant reduced oxidative stress and membrane potential changes) and in the percentage of cells apoptosis. While blocking LIGHT with the soluble fusion protein LTßR-Ig or HVEM-Ig accelerated the HK-2 cells apoptosis. In conclusion, LIGHT deficiency aggravates Cis-AKI by promoting mitochondrial apoptosis pathways.

LIGHT aggravates sepsis-associated acute kidney injury via TLR4-MyD88-NF-κB pathway.

Sepsis-associated acute kidney injury (SA-AKI) is a common clinical critical care syndrome. It has received increasing attention due to its high morbidity and mortality; however, its pathophysiological mechanisms remain elusive. LIGHT, the 14th member of the tumour necrosis factor (TNF) superfamily and a bidirectional immunoregulatory molecule that regulates inflammation, plays a pivotal role in disease pathogenesis. In this study, mice with an intraperitoneal injection of LPS and HK-2 cells challenged with LPS were employed as a model of SA-AKI in vivo and in vitro, respectively. LIGHT deficiency notably attenuated kidney injury in pathological damage and renal function and markedly mitigated the inflammatory reaction by decreasing inflammatory mediator production and inflammatory cell infiltration in vivo. The TLR4-Myd88-NF-κB signalling pathway in the kidney of LIGHT knockout mice was dramatically down-regulated compared to the controls. Recombinant human LIGHT aggravated LPS-treated HK-2 cell injury by up-regulating the expression of the TLR4-Myd88-NF-κB signalling pathway and inflammation levels. TAK 242 (a selective TLR4 inhibitor) reduced this trend to some extent. In addition, blocking LIGHT with soluble receptor fusion proteins HVEM-Fc or LTßR-Fc in mice attenuated renal dysfunction and pathological damage in SA-AKI. Our findings indicate that LIGHT aggravates inflammation and promotes kidney damage in LPS-induced SA-AKI via the TLR4-Myd88-NF-κB signalling pathway, which provide potential strategies for the treatment of SA-AKI.

Successful Treatment of Allopurinol-Induced Severe Skin Reactions with Double Filtration Plasmapheresis: A Case Report.

Severe cutaneous adverse reactions (SCAR) are uncommon and acute and frequently represent a drug reaction. For years, allopurinol use has remained the highest risk factor for SCARs worldwide. There are multiple risk factors for allopurinol-induced SCARs, including genetic and non-genetic factors. Renal failure has been found to be an important factor resulting in allopurinol-induced SCARs with greater severity and poorer prognosis. An 80-year-old female was admitted to our hospital after administration of allopurinol in December 2018. She developed erythaematous skin of the epidermis of the hips, which rapidly extended over the trunk and limbs, resulting in itching and flaking. The presumptive diagnosis was a drug-induced SCAR. Despite treatment with glucocorticoids and kidney support therapy, the skin lesions extended over the entire body. Fortunately, the progression of pruritic erythema was stopped by double-filtration plasmapheresis (DFPP). DFPP was discontinued after the signs of skin inflammation were no longer visible. Her skin, but not kidney function, recovered after 10 days of hospitalization. She tolerated DFPP well without development of any severe complications. We present here a case of allopurinol-induced SCAR, which was successfully treated with DFPP.

A well-directional three-dimensional DNA walking nanomachine that runs in an orderly manner.

Herein, we report a three-dimensional (3D) DNA walking nanomachine innovatively constructed from a functionalized 3D DNA track, which runs in an orderly manner with favorable directionality to allow for programming certain pathways of information transduction for some target tasks. The nanomachine was constructed using a departure station of walker (UB + W) and a functionalized 3D track, which was made up of a rolling circle amplification (RCA)-generated backbone chain and numerous triangular rung units with stators (UA + S) assembled into a repeating array along the backbone. A specific domain (SD) was designed at the 5'-end of the backbone to capture the UB + W, and stators with specific RNA substrates were immobilized at the three UA corners for the DNA walker to travel on. Powered by 10-23 DNAzyme, the DNA walker started moving from the SD end to the other end of the track by the autonomous cleavage of RNA substrates. Significantly, the homogeneous distribution of stators in the longitudinal and horizontal extensions paved a specific path for each walker to move along the 3D track. This resulted in random and inactive self-avoiding walking; thus, the nanomachine exhibited good executive ability. These properties allowed the DNA walking nanomachine to program the certain pathways of information transduction for the stepwise and programmed execution of some target tasks, such as the synthesis of specific polyorganics and cargo delivery. We believe that such a 3D DNA walking nanomachine could enrich the concept in the field of dynamic DNA nanotechnology, and may improve the development of novel DNA nanomachines in cargo delivery and composite product synthesis.

[LIGHT/ TNFSF14 alleviates cisplatin-induced acute kidney injury in mice and its mechanism].

Objective To investigate the role of LIGHT/TNFSF14 (TNF superfamily protein 14) in cisplatin-induced acute kidney injury (Cis-AKI) in mice and explore the underlying mechanism. Methods Male wild-type (WT) and LIGHT gene knockout (LIGHT-/-) C57BL/6 mice were selected and divided into four groups: saline- and cisplatin-treated WT mice, saline- and cisplatin-treated LIGHT-/- mice. The cisplatin groups were given a single intraperitoneal injection of cisplatin (20 mg/kg, 200 µL), and the saline groups were injected with equal volume of normal saline (9 g/L). After 72 hours, the mice were sacrificed, blood was taken from the eyeball, and kidney tissues were collected. Blood urea nitrogen (BUN) and serum creatinine (Scr) were measured by automatic biochemical analyzer. HE staining was used to detect the histopathological changes of kidney tissues, The mRNA levels of LIGHT, kidney injury molecule 1 (KIM-1), interleukin-6 (IL-6), monocyte chemotactic protein 1 (MCP-1), and tumor necrosis factor (TNF-α) were detected by real-time quantitative PCR. The protein levels of LIGHT, Bcl2, BAX and cytochrome C were detected by Western blot analysis or immunohistochemical staining. Results Compared with saline-treated WT mice, the expression of LIGHT in renal tissue of cisplatin-treated WT mice significantly increased. Compared with cisplatin-treated WT mice, the kidney injury in cisplatin-treated LIGHT-/- mice was more serious; BUN and Scr increased; and the pathological damage of kidney tissue was more obvious. Moreover, the mRNA levels of IL-6, MCP-1 and TNF-α, as well as the protein levels of BAX and cytochrome C increased, while the protein levels of Bcl2 decreased. Conclusion LIGHT plays a protective role in Cis-AKI, which may be related to down-regulated secretion of inflammatory factors and decreased apoptosis.

Anatomy Revisited: Hemodialysis Catheter Malposition into the Chest.

In most situations, central catheters are implanted in the right jugular vein as initial access for hemodialysis. However, after repeated punctures, the proximal vessels become stenosed and thrombosed and misplacement is likely to occur. Correct catheter position in the vein can be easily ascertained with X-ray or cross-sectional CT imaging. In this report, we describe the case of a 77-year-old patient on chronic hemodialysis via catheter due to arteriovenous fistula dysfunction. We placed a cuffed-tunneled hemodialysis catheter in the left internal jugular vein. Malpositioning of the catheter led to perforation of the great veins and migration of the catheter tip into the chest. It is important to be aware of the risk of potential incorrect positioning of dialysis catheters. Due to the stenosis and fragility of the vessel wall, perforation may occur. In cases of doubt, correct placement of large-bore catheters via the internal jugular vein should be verified by means of appropriate imaging before hemodialysis is performed.

Plasmapheresis Therapy in Kidney Transplant Rejection.

Kidney transplantation (KT) is considered an optimal treatment strategy for end-stage renal disease. But human leukocyte antigen-sensitized, ABO-incompatible and antibody-mediated rejection might be the alarming hurdles in KT. Therapeutic plasma exchange is the mainstay of the antibody reduction therapy for reducing autoantibody more effectively. Even in the treatment for highly sensitized patients, it has played an indispensable role. However, clinicians should tailor therapies to individual patient's needs and multimodal treatment will bring better outcomes. Early diagnosis and precise treatment would reduce morbidity, mortality, and economic costs.

Perylene Derivative/Luminol Nanocomposite as a Strong Electrochemiluminescence Emitter for Construction of an Ultrasensitive MicroRNA Biosensor.

In this work, an electrochemiluminescent (ECL) biosensor was constructed on the basis of amino-modified 3,4,9,10-perylenetetracarboxylic dianhydride/luminol (PTC-NH2/Lu) nanocomposite as emitter and bipedal DNA walker signal amplification strategy for ultrasensitive detection of microRNA-21 (miRNA-21). The PTC-NH2/Lu nanocomposite was prepared as signal tag via π-π stacking molecular assembly, in which amino-modified 3,4,9,10-perylenetetracarboxylic dianhydride (PTC-NH2) as a novel coreaction accelerator significantly enhanced the ECL emission of luminol-H2O2 system. Moreover, target miRNA-21 triggered bipedal DNA walker was powered by toehold-mediated strand displacement reaction (TSDR) for signal amplification. Consequently, the proposed ECL biosensor achieved ultrasensitive detection of miRNA-21 with a linear range from 100 aM to 100 pM and a limit of detection of 33 aM. Simultaneously, the biosensor was also successfully applied to detect target miRNA-21 in lysates from human cancer cells. As a result, this work constructed a new signal amplification platform, exhibiting great application potential in biomedical analysis and early clinical diagnostics.

Highly sensitive electrochemical nuclear factor kappa B aptasensor based on target-induced dual-signal ratiometric and polymerase-assisted protein recycling amplification strategy.

In this work, an amplified electrochemical ratiometric aptasensor for nuclear factor kappa B (NF-κB) assay based on target binding-triggered ratiometric signal readout and polymerase-assisted protein recycling amplification strategy is described. To demonstrate the effect of "signal-off" and "signal-on" change for the dual-signal electrochemical ratiometric readout, the thiol-hairpin DNA (SH-HD) hybridizes with methylene blue (MB)-modified protection DNA (MB-PD) to form capture probes, which is rationally introduced for the construction of the assay platform. On the interface, the probes can specifically bind to target NF-κB and expose a toehold region which subsequently hybridizes with the ferrocene (Fc)-modified DNA strand to take the Fc group to the electrode surface, accompanied by displacing MB-PD to release the MB group from the electrode surface, leading to the both "signal-on" of Fc (IFc) and "signal-off" of MB (IMB). In order to improve the sensitivity of the electrochemical aptasensor, phi29-assisted target protein recycling amplification strategy was designed to achieve an amplified ratiometric signal. With the above advantages, the prepared aptasensor exhibits a wide linear range of 0.1pgmL-1 to 15ngmL-1 with a low detection limit of 0.03pgmL-1. This strategy provides a simple and ingenious approach to construct ratiometric electrochemical aptasensor and shows promising potential applications in multiple disease marker detection by changing the recognition probe.

Impedimetric aptasensor for nuclear factor kappa B with peroxidase-like mimic coupled DNA nanoladders as enhancer.

In this work, we developed a sensitive and universal aptasensor for nuclear factor kappa B (NF-κB) detection based on peroxidase-like mimic coupled DNA nanoladders for signal amplification. The dsDNA formed by capture DNA S1 and NF-κB binding aptamer (NBA) was firstly assembled on electrode surface. The presence of target NF-κB then led to the leave of NBA from electrode surface and thus provided the binding sites for immobilizing initiator to trigger in situ formation of DNA nanoladders on electrode surface. Since the peroxidase-like mimic manganese (III) meso-tetrakis (4-Nmethylpyridyl)-porphyrin (MnTMPyP) interacts with DNA nanoladders via groove binding, the insoluble benzo-4-chlorohexadienone (4-CD) precipitation derived from the oxidation of 4-chloro-1-naphthol (4-CN) could be formed on electrode surface in the presence of H2O2, resulting in a significantly amplified EIS signal output for quantitative target analysis. As a result, the developed aptasensor showed a low detection limit of 7pM and a wide linear range of 0.01-20nM. Featured with high sensitivity and label-free capability, the proposed sensing scheme can thus offer new opportunities for achieving sensitive, selective and stable detection of different types of target proteins.

Indoleamine 2, 3-Dioxgenase Transfected Mesenchymal Stem Cells Induce Kidney Allograft Tolerance by Increasing the Production and Function of Regulatory T Cells.

BACKGROUND: The immunoregulatory properties of mesenchymal stem cells (MSCs) have been well characterized in vitro. However, the role of MSCs in organ transplantation remains unclear. The purpose of this study was to examine the role of indoleamine 2, 3-dioxgenase (IDO)-transfected MSCs in immunoregulation both in vitro and in vivo. METHODS: Wild-type (WT) MSCs, empty lentivirus-transfected MSCs (Lenti-MSCs) or IDO-lentivirus-transfected MSCs (IDO-MSCs) were cocultured with peripheral blood mononuclear cells (PBMCs) or CD4CD25 regulatory T (Treg) cells to examine the impact of IDO on the immunoregulatory properties of MSCs in vitro. WT-MSCs, Lenti-MSCs or IDO-MSCs (2 × 10/kg) were intravenously injected into rabbit renal transplant recipients immediately after surgery to examine the role of IDO-MSCs in tolerance induction in vivo. RESULTS: Lentivirus infection of MSCs resulted in stable expression of IDO. The IDO-MSCs inhibited the proliferation of CD4CD25 effector T cells to a greater extent than WT-MSCs. Coculture of PBMCs and IDO-MSCs induced a higher percentage of CD4CD25Foxp3 Treg cells in PBMCs. Additionally, the antigen-specific suppressive function of these CD4CD25 Treg cells was increased. The IDO-MSCs-treated Treg cells showed upregulated expression of cytotoxic T-lymphocyte-associated antigen 4 and increased secretion of IL-10 and TGF-ß. Low doses of IDO-MSCs prolonged graft survival and induced tolerance by inducing antigen-specific CD4CD25 Treg cells, as evidenced by the finding that IDO-MSCs-treated kidney transplant recipients accepted donor-specific skin grafts but rejected third-party grafts. CONCLUSIONS: The IDO increased the direct immunoregulatory properties of MSCs. The IDO-MSCs enhanced the expression and function of CD4CD25 Foxp3 Treg cells and induced allograft tolerance.

Mediator-free triple-enzyme cascade electrocatalytic aptasensor with exonuclease-assisted target recycling and hybridization chain reaction amplification.

The amplified sensitive detection of protein is essential to biomedical research as well as clinical diagnosis. Here, we developed an ultrasensitive mediator-free triple-enzyme cascade electrocatalytic aptasensor for thrombin detection on the basis of exonuclease-assisted target recycling and hybridization chain reaction (HCR) amplification strategy. The double strands constructed by the hybridization of thrombin binding aptamer (S1) with its complementary strand (S2) were firstly assembled on the electrode. Upon addition of target to the system, the S1 recognized thrombin and left off electrode to make space for assembly of hybrid-primer probe (H0). Then, the H0 triggered the HCR to form the multi-functional hemin/G-quadruplex DNAzyme nanowires. In the mediator-free triple-enzyme cascade electrocatalytic amplification system, the hemin/G-quadruplex DNAzyme nanowires here simultaneously played three roles: the redox probe, NADH oxidase and HRP-mimicking DNAzyme, respectively, which effectively avoided the fussy redox probe and enzyme labeling process, serving a useful alternative or supplement to conventional assays that typically suffer from complexity and poor sensitivity. Additionally, in order to improve the assembly amount of hemin/G-quadruplex DNAzyme nanowire, the exonuclease-assisted target recycling amplification was used for the continuous removal of S1. As a result, the proposed method can detect thrombin specifically with a detection limit as low as 20 fM.

Two novel antimicrobial peptides from centipede venoms.

Centipede venoms are complex mixtures of biochemically and pharmacologically active components such as peptides and proteins. Very few are known about their pharmacological actions. The present work reports the structural and functional characterization of two antimicrobial peptides (scolopin 1 and -2) identified from centipede venoms of Scolopendra subspinipes mutilans by Sephadex gel filtration and reverse-phase high-performance liquid chromatography (RP-HPLC). The amino acid sequences of scolopin 1 and -2 were FLPKMSTKLRVPYRRGTKDYH and GILKKFMLHRGTKVYKMRTLSKRSH determined by Edman degradation and matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). Both scolopin 1 and -2 showed strong antimicrobial activities against tested microorganisms including Gram-positive/negative bacteria and fungi. They also showed moderate hemolytic activity against both human and rabbit red cells. This is the first report of antimicrobial peptides from centipedes.

Advanced oxidation protein products induce monocyte chemoattractant protein-1 expression via p38 mitogen-activated protein kinase activation in rat vascular smooth muscle cells.

BACKGROUND: Advanced oxidation protein products (AOPPs) are new uremic toxins reported by Witko-Sarsat in 1996, which are associated with the pathogenesis of atherosclerosis. However, the mechanisms by which AOPPs enhance atherosclerosis have not been fully understood. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine which stimulates migration of monocytes and plays a critical role in the development of atherosclerosis. In this study, we investigated the effect of AOPPs on MCP-1 expression in cultured vascular smooth muscle cells (VSMCs). METHODS: VSMCs were cultured and then co-incubated with AOPP (200 micromol/L, 400 micromol/L) for different times with or without pretreatment with specific p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580. RT-PCR and Western blott were used to detect MCP-1 mRNA and protein expression at different time points after AOPP stimulation in rat smooth muscle cells. Western blot was used to detect the expression of phosphorylated p38 MAPK. RESULTS: Treatment of VSMC with AOPPs resulted in a significant increase of the expression of MCP-1 mRNA and protein in time- and dose-dependent manner, and could activated p38 MAPK. Pretreatment of VSMCs with SB203580 resulted in a dose-dependent inhibition of AOPPs-induced MCP-1 mRNA and protein expression. CONCLUSIONS: AOPPs can stimulate MCP-1 expression via p38 MAPK in VSMCs. This suggests that AOPPs might contribute to the formation of atherosclerosis through this proinflammatory effect.