Advances in the understanding of the production, modification and applications of xylanases in the food industry.

Xylanases have broad applications in the food industry to decompose the complex carbohydrate xylan. This is applicable to enhance juice clarity, improve dough softness, or reduce beer turbidity. It can also be used to produce prebiotics and increase the nutritional value in foodstuff. However, the low yield and poor stability of most natural xylanases hinders their further applications. Therefore, it is imperative to explore higher-quality xylanases to address the potential challenges that appear in the food industry and to comprehensively improve the production, modification, and utilization of xylanases. Xylanases, due to their various sources, exhibit diverse characteristics that affect production and activity. Most fungi are suitable for solid-state fermentation to produce xylanases, but in liquid fermentation, microbial metabolism is more vigorous, resulting in higher yield. Fungi produce higher xylanase activity, but bacterial xylanases perform better than fungal ones under certain extreme conditions (high temperature, extreme pH). Gene and protein engineering technology helps to improve the production efficiency of xylanases and enhances their thermal stability and catalytic properties.

Targeting peroxisome proliferator-activated receptor γ proteasomal degradation by magnolol is a potential avenue for adipogenesis-mediated metabolic homeostasis.

OBJECTIVE: Adipogenesis has been recognized as an attractive avenue for maintaining systemic homeostasis, with peroxisome proliferator-activated receptor γ (PPARγ) showing predominant roles in this process. This study aims to identify promising drug candidates by targeting PPARγ for adipogenesis-based metabolic homeostasis and to clarify the detailed mechanisms. METHODS: Molecular events contributing to adipogenesis were screened, which identified PPARγ as having the predominant role. Promising agents of adipogenesis agonism were screened using a PPARγ-based luciferase reporter assay. The functional capacity and molecular mechanisms of magnolol were intensively examined using 3T3-L1 preadipocytes and dietary models. RESULTS: This study found that F-box only protein 9 (FBXO9)-mediated lysine 11 (K11)-linked ubiquitination and proteasomal degradation of PPARγ are critically required during adipogenesis and systemic homeostasis. Notably, magnolol was identified as a potent adipogenesis activator by stabilizing PPARγ. The pharmacological mechanisms investigations clarified that magnolol directly binds to PPARγ and markedly interrupts its interaction with FBXO9, leading to a decline in K11-linked ubiquitination and proteasomal degradation of PPARγ. Clinically important, magnolol treatment significantly facilitates adipogenesis in vitro and in vivo. CONCLUSIONS: The downregulation of K11-linked ubiquitination of PPARγ caused by FBOX9 is essentially required for adipogenesis, while targeting PPARγ-FBXO9 interaction provides a new avenue for the therapy of adipogenesis-related metabolic disorder.

Network-based analysis identifies key regulatory transcription factors involved in skin aging.

Skin aging is a complex process involving intricate genetic and environmental factors. In this study, we performed a comprehensive analysis of the transcriptional regulatory landscape of skin aging in canines. Weighted Gene Co-expression Network Analysis (WGCNA) was employed to identify aging-related gene modules. We subsequently validated the expression changes of these module genes in single-cell RNA sequencing (scRNA-seq) data of human aging skin. Notably, basal cell (BC), spinous cell (SC), mitotic cell (MC), and fibroblast (FB) were identified as the cell types with the most significant gene expression changes during aging. By integrating GENIE3 and RcisTarget, we constructed gene regulation networks (GRNs) for aging-related modules and identified core transcription factors (TFs) by intersecting significantly enriched TFs within the GRNs with hub TFs from WGCNA analysis, revealing key regulators of skin aging. Furthermore, we demonstrated the conserved role of CTCF and RAD21 in skin aging using an H2O2-stimulated cell aging model in HaCaT cells. Our findings provide new insights into the transcriptional regulatory landscape of skin aging and unveil potential targets for future intervention strategies against age-related skin disorders in both canines and humans.

A high-throughput drug screening identifies luteolin as a therapeutic candidate for pathological cardiac hypertrophy and heart failure.

Background: Pathological cardiac hypertrophy is commonly resulted from sustained pressure overload and/or metabolic disorder and eventually leads to heart failure, lacking specific drugs in clinic. Here, we aimed to identify promising anti-hypertrophic drug(s) for heart failure and related metabolic disorders by using a luciferase reporter-based high-throughput screening. Methods: A screen of the FDA-approved compounds based on luciferase reporter was performed, with identified luteolin as a promising anti-hypertrophic drug. We systematically examined the therapeutic efficacy of luteolin on cardiac hypertrophy and heart failure in vitro and in vivo models. Transcriptome examination was performed to probe the molecular mechanisms of luteolin. Results: Among 2,570 compounds in the library, luteolin emerged as the most robust candidate against cardiomyocyte hypertrophy. Luteolin dose-dependently blocked phenylephrine-induced cardiomyocyte hypertrophy and showed extensive cardioprotective roles in cardiomyocytes as evidenced by transcriptomics. More importantly, gastric administration of luteolin effectively ameliorated pathological cardiac hypertrophy, fibrosis, metabolic disorder, and heart failure in mice. Cross analysis of large-scale transcriptomics and drug-target interacting investigations indicated that peroxisome proliferator activated receptor γ (PPARγ) was the direct target of luteolin in the setting of pathological cardiac hypertrophy and metabolic disorders. Luteolin can directly interact with PPARγ to inhibit its ubiquitination and subsequent proteasomal degradation. Furthermore, PPARγ inhibitor and PPARγ knockdown both prevented the protective effect of luteolin against phenylephrine-induced cardiomyocyte hypertrophy in vitro. Conclusion: Our data clearly supported that luteolin is a promising therapeutic compound for pathological cardiac hypertrophy and heart failure by directly targeting ubiquitin-proteasomal degradation of PPARγ and the related metabolic homeostasis.

Multiple omics study identifies an interspecies conserved driver for nonalcoholic steatohepatitis.

Lipotoxicity is a recognized pathological trigger and accelerator of nonalcoholic steatohepatitis (NASH). However, the molecular basis of lipotoxicity-induced NASH remains elusive. Here, we systematically mapped the changes in hepatic transcriptomic landscapes in response to lipotoxic insults across multiple species. Conserved and robust activation of the arachidonic acid pathway, in particular the arachidonate 12-lipoxygenase (ALOX12) gene, was closely correlated with NASH severity in humans, macaques with spontaneously developed NASH, as well as swine and mouse dietary NASH models. Using gain- and loss-of-function studies, we found that ALOX12 markedly exacerbated NASH in both mice and Bama pig models. ALOX12 was shown to induce NASH by directly targeting acetyl-CoA carboxylase 1 (ACC1) via a lysosomal degradation mechanism. Overall, our findings reveal a key molecular driver of NASH pathogenesis and suggest that ALOX12-ACC1 interaction may be a therapeutic target in NASH.

A small molecule targeting ALOX12-ACC1 ameliorates nonalcoholic steatohepatitis in mice and macaques.

Nonalcoholic steatohepatitis (NASH) is a progressive liver disease and has become a leading indication for liver transplantation in the United States. The development of effective therapies for NASH is a major unmet need. Here, we identified a small molecule, IMA-1, that can treat NASH by interrupting the arachidonate 12-lipoxygenase (ALOX12)­acetyl-CoA carboxylase 1 (ACC1) interaction. IMA-1 markedly blocked diet-induced NASH progression in both male mice and Cynomolgus macaque therapeutic models. The anti-NASH efficacy of IMA-1 was comparable to ACC inhibitor in both species. Protein docking simulations and following functional experiments suggested that the anti-NASH effects of IMA-1 were largely dependent on its direct binding to a pocket in ALOX12 proximal to its ACC1-interacting surface instead of inhibiting ALOX12 lipoxygenase activity. IMA-1 treatment did not elicit hyperlipidemia, a known side effect of direct inhibition of ACC enzymatic activity, in both mice and macaques. These findings provide proof of concept across multiple species for the use of small molecule­based therapies for NASH.

miR-491-5p inhibits the proliferation and migration of A549 cells by FOXP4.

Aberrant expression of microRNAs (miRNAs/miRs) plays a key role in the development of non-small cell lung cancer (NSCLC). In the present study, lower miRNA (miR)-491-5p levels and a higher forkhead box P4 (FOXP4) mRNA level were observed in NSCLC tissues and cell lines, compared to adjacent tissues and the normal human lung epithelial cell line BEAS-2B, respectively. A549 cell proliferation and migration were inhibited upon transfection of miR-491-5p mimics compared to miR-negative control (NC) mimics. In addition, compared to miR-NC mimics, overexpression of miR-491-5p decreased FOXP4 expression, while downregulation of miR-491-5p increased FOXP4 expression in A549 cells. The dual luciferase assay confirmed that the 3'untranslated region of FOXP4 was a target for miR-491-5p in A549 cells. Moreover, compared with the control short hairpin (sh)RNA, there was lower expression levels of TGF-ß and its downstream targets (MMP-2 and MMP-9) in the FOXP4 shRNA group. Similarly, compared to miR-NC mimics, overexpression of miR-491-5p decreased MMP-2 and MMP-9 expression levels. In FOXP4-knockdown A549 cells, overexpression of miR-491-5p showed little effect on cell proliferation/migration. In A549 cells, overexpression of FOXP4 partially reversed the miR-491-5p mimics-induced inhibition on the cell proliferation and migration. These results may provide new insights into the role of miR-491-5p in NSCLC.

A kinome screen reveals that Nemo-like kinase is a key suppressor of hepatic gluconeogenesis.

Antihyperglycemic therapy is an important priority for the treatment of type 2 diabetes (T2D). Excessive hepatic glucose production (HGP) is a major cause of fasting hyperglycemia. Therefore, a better understanding of its regulation would be important to develop effective antihyperglycemic therapies. Using a gluconeogenesis-targeted kinome screening approach combined with transcriptome analyses, we uncovered Nemo-like kinase (NLK) as a potent suppressor of HGP. Mechanistically, NLK phosphorylates and promotes nuclear export of CRTC2 and FOXO1, two key regulators of hepatic gluconeogenesis, resulting in the proteasome-dependent degradation of the former and the inhibition of the self-transcriptional activity and expression of the latter. Importantly, the expression of NLK is downregulated in the liver of individuals with diabetes and in diabetic rodent models and restoring NLK expression in the mouse model ameliorates hyperglycemia. Therefore, our findings uncover NLK as a critical player in the gluconeogenic regulatory network and as a potential therapeutic target for T2D.

STEAP3 (Six-Transmembrane Epithelial Antigen of Prostate 3) Inhibits Pathological Cardiac Hypertrophy.

Pathological cardiac hypertrophy is one of the major predictors and inducers of heart failure, the end stage of various cardiovascular diseases. However, the molecular mechanisms underlying pathogenesis of pathological cardiac hypertrophy remain largely unknown. Here, we provided the first evidence that STEAP3 (Six-Transmembrane Epithelial Antigen of Prostate 3) is a key negative regulator of this disease. We found that the expression of STEAP3 was reduced in pressure overload-induced hypertrophic hearts and phenylephrine-induced hypertrophic cardiomyocytes. In a transverse aortic constriction-triggered mouse cardiac hypertrophy model, STEAP3 deficiency remarkably deteriorated cardiac hypertrophy and fibrosis, whereas the opposite phenotype was observed in the cardiomyocyte-specific STEAP3 overexpressing mice. Accordingly, STEAP3 significantly mitigated phenylephrine-induced cell enlargement in primary neonatal rat cardiomyocytes. Mechanistically, via RNA-seq and immunoprecipitation-mass screening, we demonstrated that STEAP3 directly bond to Rho family small GTPase 1 and suppressed the activation of downstream mitogen-activated protein kinase-extracellular signal-regulated kinase signaling cascade. Remarkably, the antihypertrophic effect of STEAP3 was largely blocked by overexpression of constitutively active mutant Rac1 (G12V). Our study indicates that STEAP3 serves as a novel negative regulator of pathological cardiac hypertrophy by blocking the activation of the Rac1-dependent signaling cascade and may contribute to exploring effective therapeutic strategies of pathological cardiac hypertrophy treatment.

Polydopamine-based surface modification of hemoglobin particles for stability enhancement of oxygen carriers.

Templated assembly techniques have been extensively used to develop various types of hemoglobin (Hb) loaded particles with improved performance. However, several instability issues must still be solved, including Hb exposure, enhanced Hb auto-oxidation, and the relatively weak binding of Hb to cross-linkers. Herein, to meet the stability requirements for novel hemoglobin-based oxygen carriers (HBOCs), hemoglobin-polydopamine particles (Hb-PDA) were fabricated using a mild process that combines the co-precipitation of Hb and an inorganic template with the spontaneous adhesion of PDA. The Hb-PDA showed uniform size distribution, chemical integrity of both Hb and PDA, high biocompatibility, and robust oxygen delivery. Our results demonstrated that the use of polydopamine as a biocompatible coating material reduced Hb leakage from the particles under both static and flow conditions, thus mitigating the toxicity associated with free Hb and strengthening the stability of Hb particles. In addition, Hb-PDA reduced HUVEC (Human Umbilical Vein Cells) oxidative injury and scavenged 85% of the available hydroxyl radicals, exhibiting its potential to act as an antioxidant for encapsulated Hb. Hb-PDA therefore shows significant promise as a cell-like structurally and functionally stable HBOCs.

Hepatocyte TNF Receptor-Associated Factor 6 Aggravates Hepatic Inflammation and Fibrosis by Promoting Lysine 6-Linked Polyubiquitination of Apoptosis Signal-Regulating Kinase 1.

Activation of apoptosis signal-regulating kinase 1 (ASK1) is a key driving force of the progression of nonalcoholic steatohepatitis (NASH) and represents an attractive therapeutic target for NASH treatment. However, the molecular and cellular mechanisms underlying ASK1 activation in the pathogenesis of NASH remain incompletely understood. In this study, our data unequivocally indicated that hyperactivated ASK1 in hepatocytes is a potent inducer of hepatic stellate cell (HSC) activation by promoting the production of hepatocyte-derived factors. Our previous serial studies have shown that the ubiquitination system plays a key role in regulating ASK1 activity during NASH progression. Here, we further demonstrated that tumor necrosis factor receptor-associated factor 6 (TRAF6) promotes lysine 6 (Lys6)-linked polyubiquitination and subsequent activation of ASK1 to trigger the release of robust proinflammatory and profibrotic factors in hepatocytes, which, in turn, drive HSC activation and hepatic fibrosis. Consistent with the in vitro findings, diet-induced liver inflammation and fibrosis were substantially attenuated in Traf6+/- mice, whereas hepatic TRAF6 overexpression exacerbated these abnormalities. Mechanistically, Lys6-linked ubiquitination of ASK1 by TRAF6 facilitates the dissociation of thioredoxin from ASK1 and N-terminal dimerization of ASK1, resulting in the boosted activation of ASK1-c-Jun N-terminal kinase 1/2 (JNK1/2)-mitogen-activated protein kinase 14(p38) signaling cascade in hepatocytes. Conclusion: These results suggest that Lys6-linked polyubiquitination of ASK1 by TRAF6 represents a mechanism underlying ASK1 activation in hepatocytes and a key driving force of proinflammatory and profibrogenic responses in NASH. Thus, inhibiting Lys6-linked polyubiquitination of ASK1 may serve as a potential therapeutic target for NASH treatment.

Improved flowing behaviour and gas exchange of stored red blood cells by a compound porous structure.

Storage lesions in red blood cells (RBCs) hinder efficient circulation and tissue oxygenation. The absence of flow mechanics and gas exchange may contribute to this problem. To test if in vitro compensation of flow mechanics and gas exchange helps RBC recovery, three-dimensional polydimethylsiloxane (PDMS) porous structures were fabricated with a sugar mould, simulating lung alveoli. RBC suspensions were passed through the porous structure cyclically, simulating in vivo blood circulation. Acid-base indices, partial gas pressures, ions, glucose and RBC indices were analyzed. An atomic force microscope was used to investigate local mechanical properties of intact RBCs. RBCs suspensions that passed through the porous structures had a higher pH and oxygen partial pressure, and a lower potassium concentration and carbon dioxide partial pressure. Meantime they had better biochemical properties relative to static samples, namely, they exhibited a more homogenous distribution of Young's Modulus. RBCs that passed through a PDMS porous structure were healthier than static ones, giving hints to prevent RBC storage lesions.

Influence of polydopamine-mediated surface modification on oxygen-release capacity of haemoglobin-based oxygen carriers.

Oxidative toxicity has impeded the development of haemoglobin-based oxygen carriers (HBOCs) by causing methaemoglobin (MetHb) formation and inducing oxidative stress. In our previous work, polydopamine-coated haemoglobin (Hb-PDA) nanoparticles have been designed and synthesized with the capacity to reduce oxidative toxicity. In this investigation, the mass ratio of dopamine (DA) to haemoglobin (Hb) and the pH value are found to be the primary factors that influence preparation of Hb-PDA nanoparticles. X-ray photoelectron spectroscopy showed that the catechol groups of DA play a crucial role in the modification of Hb surface. Hb-PDA nanoparticles were found to exhibit oxidative protection from hydrogen peroxide (H2O2) and the change of mitochondrial membrane potential showed that the Hb-PDA nanoparticles reduced H2O2-induced apoptosis. It is demonstrated that modification of PDA could maintain the oxygen-release capacity of Hb. These findings confirm that Hb-PDA nanoparticles possess restrained oxidative toxicity and preserve oxygen-release capacity.

In vitro and in vivo investigation of the novel Dex-bHb as oxygen carriers.

The development of hemoglobin-based oxygen carriers (HBOCs) is a persistent and urgent need in biomedicine. As a potential HBOCs, Dextran-hemoglobin (Dex-bHb) has been developed over the past years. The novel Dex-bHb, whose thiol group of Cys-93(ß) was reversibly protected, was produced and the characteristics were evaluated in our previous study. Herein, blood compatibility was characterized in terms of the red blood cell aggregation and hemolysis rate in vitro, and Dex-bHb showed no obvious effects. After intravenous administration of Dex-bHb to golden Syrian hamsters with hemorrhages shock, it showed mean arterial pressure recovery, blood flow increase and the organ protection from serious hemorrhage injury. Consequently, Dex-bHb is hopeful to be a safe and available blood substitute.

A PEGylated bovine hemoglobin as a potent hemoglobin-based oxygen carrier.

Hemoglobin (Hb)-based oxygen carriers (HBOCs) have been used as blood substitutes in surgery medicine and oxygen therapeutics for ischemic stroke. As a potent HBOC, the PEGylated Hb has received much attention for its oxygen delivery and plasma expanding ability. Two PEGylated Hbs, Euro-Hb, and MP4 have been developed for clinical trials, using human adult hemoglobin (HbA) as the original substrate. However, HbA was obtained from outdated human blood and its quantity available from this source may not be sufficient for mass production of PEGylated HbA. In contrast, bovine Hb (bHb) has no quantity constraints for its ample resource. Thus, bHb is of potential to function as an alternative substrate to obtain a PEGylated bHb (bHb-PEG). bHb-PEG was prepared under the same reaction condition as HbA-PEG, using maleimide chemistry. The structural, functional, solution and physiological properties of bHb-PEG were determined and compared with those of HbA-PEG. bHb-PEG showed higher hydrodynamic volume, colloidal osmotic pressure, viscosity and P50 than HbA-PEG. The high P50 of bHb can partially compensate the PEGylation-induced perturbation in the R to T state transition of HbA. bHb-PEG was non-vasoactive and could efficiently recover the mean arterial pressure of mice suffering from hemorrhagic shock. Thus, bHb-PEG is expected to function as a potent HBOC for its high oxygen delivery and strong plasma expanding ability. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:252-260, 2017.

Addition of Sodium Pyruvate to Stored Red Blood Cells Attenuates Liver Injury in a Murine Transfusion Model.

RBCs undergo numerous changes during storage and stored RBCs may induce adverse effects, ultimately resulting in organ injury in transfusion recipients. We tested the hypothesis that the addition of SP to stored RBCs would improve the quality of the stored RBCs and mitigate liver injury after transfusion in a murine model. RBCs were harvested from C57BL/6J mice and stored for 14 days in CPDA-1 containing either a solution of SP in saline or saline alone. Haemolysis, the 24-hour posttransfusion recovery, the oxygen-carrying capacity, and the SOD activity of stored RBCs were evaluated. The plasma biochemistry, hepatic MDA level, MPO activity, IL-6, TNF-α concentrations, and histopathology were measured two hours after the transfusion of stored RBCs. Compared with RBCs stored in CPDA-1 and saline, the addition of SP to stored RBCs restored their oxygen-carrying capacity and SOD activity, reduced the AST activity, BUN concentrations, and LDH activity in the plasma, and decreased the MDA level, MPO activity, and concentrations of IL-6 and TNF-α in the liver. These data indicate that the addition of SP to RBCs during storage has a beneficial effect on storage lesions in vitro and subsequently alleviates liver injury after the transfusion of stored RBCs in vivo.

The mechanical properties of stored red blood cells measured by a convenient microfluidic approach combining with mathematic model.

The mechanical properties of red blood cells (RBCs) are critical to the rheological and hemodynamic behavior of blood. Although measurements of the mechanical properties of RBCs have been studied for many years, the existing methods, such as ektacytometry, micropipette aspiration, and microfluidic approaches, still have limitations. Mechanical changes to RBCs during storage play an important role in transfusions, and so need to be evaluated pre-transfusion, which demands a convenient and rapid detection method. We present a microfluidic approach that focuses on the mechanical properties of single cell under physiological shear flow and does not require any high-end equipment, like a high-speed camera. Using this method, the images of stretched RBCs under physical shear can be obtained. The subsequent analysis, combined with mathematic models, gives the deformability distribution, the morphology distribution, the normalized curvature, and the Young's modulus (E) of the stored RBCs. The deformability index and the morphology distribution show that the deformability of RBCs decreases significantly with storage time. The normalized curvature, which is defined as the curvature of the cell tail during stretching in flow, suggests that the surface charge of the stored RBCs decreases significantly. According to the mathematic model, which derives from the relation between shear stress and the adherent cells' extension ratio, the Young's moduli of the stored RBCs are also calculated and show significant increase with storage. Therefore, the present method is capable of representing the mechanical properties and can distinguish the mechanical changes of the RBCs during storage. The advantages of this method are the small sample needed, high-throughput, and easy-use, which make it promising for the quality monitoring of RBCs.

Effects of synthetic colloid and crystalloid solutions on hemorheology in vitro and in hemorrhagic shock.

BACKGROUND: Plasma expanders are commonly used in the management of critically ill patients, which may exhibit altered hemorheology. We evaluated the effects of various synthetic colloids and Lactated Ringer's (LR) solution on hemorheological parameters in vitro and in a rodent hemorrhagic shock model. METHODS: For the in vitro experiments, rat blood was incubated with hydroxyethyl starch (HES) 130/0.4, HES 200/0.5, succinylated gelatine (GEL), or LR at various ratios. The control consisted of blood without dilution. The hemorheological parameters were measured after a 15-min incubation. For the in vivo study, rats were subjected to a severe volume-controlled hemorrhage and were resuscitated using a colloid solution (HES 130/0.4, HES 200/0.5, or GEL) or LR. The hemorheological parameters were measured 2 h after resuscitation. RESULTS: The GEL significantly elevated the plasma viscosity compared to the other groups. In the in vitro study, GEL and LR accelerated the erythrocyte aggregation. There was no significant difference between HES 130/0.4, HES 200/0.5, and control groups regarding the aggregation amplitude and index. In the in vivo study, the aggregation amplitude increased significantly in the GEL group compared to the HES 130/0.4, HES 200/0.5, LR, and sham groups. There was no significant difference between the groups with respect to the elongation index in vivo. CONCLUSIONS: Hydroxyethyl starch did not change the erythrocyte aggregation compared to the control. GEL significantly accelerates the erythrocyte aggregation and elevates the plasma viscosity compared to hydroxyethyl starch. The in vitro hemorheological measurements most likely provide hints for the in vivo study.

Impaired erythrocyte deformability in transgenic HO-1G143H mutant mice.

To investigate the potential effects of variation of HO-1 activity on hemorheology, this study compared the hemorheological properties between transgenic HO-1G143H mutant mice and wild-type (WT) control mice. Fresh blood samples were obtained from mice via the ocular venous sinus. The whole blood viscosity was measured using a cone-plate viscometer. Erythrocyte deformability and aggregation was measured using ektacytometry. The elongation index was significantly reduced in the HO-1G143H mutant mice compared to the WT mice at the shear rates of 600, 800, and 1,000 s(-1). The integrated elongation index was decreased in the HO-1G143H mutant mice compared to the WT mice. There was no statistically significant difference between the HO-1G143H mutant mice and the WT mice in terms of whole blood viscosity, aggregation index, amplitude of aggregation, and aggregation half time. The present study demonstrated that a reduction in HO-1 activity results in an impaired erythrocyte deformability. Although the mechanism underlying this effect remains unclear, our study brings to light the participation of HO-1 in the variations of hemorheology.

C-type natriuretic peptide attenuates LPS-induced endothelial activation: involvement of p38, Akt, and NF-κB pathways.

Endothelial activation elicited by inflammatory agents is regarded as a key event in the pathogenesis of several vascular inflammatory diseases. In the present study, the inhibitory effects and underlying mechanism of C-type natriuretic peptide (CNP) on LPS-induced endothelial activation were examined in human umbilical vein endothelial cells (HUVECs). The effect of CNP on adhesion molecule expression was assessed using quantitative real-time RT-PCR and western blotting analyses. The nuclear factor-κB (NF-κB), MAPK, and PI3K/Akt signaling pathways in LPS-stimulated HUVECs were investigated using western blotting analyses, and the production of intracellular reactive oxygen species (ROS) was measured using a fluorescence method. Pretreatment with CNP inhibited LPS-induced expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin, and P-selectin in a concentration-dependent manner. CNP suppressed the phosphorylation of p65 and NF-κB activation in LPS-stimulated cells. Moreover, CNP reduced ERK1/2 and p38 phosphorylation induced by LPS but not JNK. Furthermore, CNP induced Akt phosphorylation and activation of hemeoxygenase-1 (HO-1) expression. CNP significantly inhibited the production of intracellular ROS. These results suggest that CNP effectively attenuated LPS-induced endothelial activation by inhibiting the NF-κB and p38 signaling pathways, eliminating LPS-induced intracellular ROS production, and activating the PI3K/Akt/HO-1 pathway in HUVECs; thereby, demonstrating that CNP may be a potential therapeutic target for the treatment of sepsis and inflammatory vascular diseases.