Effects of Bone Marrow Mesenchymal Stem Cell-Derived Exosomes in Central Nervous System Diseases.

Central nervous system (CNS) diseases are one of the diseases that threaten human health. The delivery of drugs targeting the CNS has always been a significant challenge; the blood-brain barrier (BBB) is the main obstacle that must be overcome. The rise of bone marrow mesenchymal stem cell (BMSC) therapy has brought hope for the treatment of CNS diseases. However, the problems of low homing rate, susceptibility differentiation into astrocytes, immune rejection, and formation of iatrogenic tumors of transplanted BMSCs limit their clinical application. Bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exos) have become a hot research topic in the treatment of CNS diseases in recent years because of their excellent histocompatibility, low immunogenicity, ease of crossing the BBB, and their ability to serve as natural carriers for treatment. This article reviews the mechanisms of BMSC-Exos in CNS diseases and provides direction for further research.

Structural basis of human SNAPc recognizing proximal sequence element of snRNA promoter.

In eukaryotes, small nuclear RNAs (snRNAs) function in many fundamental cellular events such as precursor messenger RNA splicing, gene expression regulation, and ribosomal RNA processing. The snRNA activating protein complex (SNAPc) exclusively recognizes the proximal sequence element (PSE) at snRNA promoters and recruits RNA polymerase II or III to initiate transcription. In view that homozygous gene-knockout of SNAPc core subunits causes mouse embryonic lethality, functions of SNAPc are almost housekeeping. But so far, the structural insight into how SNAPc assembles and regulates snRNA transcription initiation remains unclear. Here we present the cryo-electron microscopy structure of the essential part of human SNAPc in complex with human U6-1 PSE at an overall resolution of 3.49 Å. This structure reveals the three-dimensional features of three conserved subunits (N-terminal domain of SNAP190, SNAP50, and SNAP43) and explains how they are assembled into a stable mini-SNAPc in PSE-binding state with a "wrap-around" mode. We identify three important motifs of SNAP50 that are involved in both major groove and minor groove recognition of PSE, in coordination with the Myb domain of SNAP190. Our findings further elaborate human PSE sequence conservation and compatibility for SNAPc recognition, providing a clear framework of snRNA transcription initiation, especially the U6 system.

Comparative study on the main active components of Baoyuan decoction in plasma and urine of normal and heart failure rats.

The global morbidity and mortality of heart failure has been increasing in recent years. Traditional Chinese medicine (TCM) was increasingly used to treat cardiovascular diseases. Baoyuan decoction (BYD) was a famous classical prescription in China. Modern pharmacological studies showed that it had obvious therapeutic effects on cardiovascular diseases, but its pathological pharmacokinetic studies were unclear. In this research, the absorption of 16 bioactive components in plasma and the excretion of 9 representative components in urine of control rats and isoproterenol (ISO)-induced heart failure rats were studied using the large-volume direct-injection LC-MS method established by our research group. The results indicated that flavonoid constituents exhibited quicker absorption and elimination than saponin constituents after oral administration of BYD. The half-life period of some bioactive compounds in the model group was increased, which contributed to the longer therapeutic effect. The cumulative excretion rate of major flavonoid components of BYD decreased significantly in the ISO-induced heart failure rats.

Pharmacokinetics/pharmacometabolomics-pharmacodynamics reveals the synergistic mechanism of a multicomponent herbal formula, Baoyuan decoction against cardiac hypertrophy.

Multicomponent herbal formulas (MCHFs) have earned a wide reputation for their definite efficacy in preventing or treating chronic complex diseases. However, holistic elucidation of the causal relationship between the bioavailable ingredients of MCHFs and their multitarget interactions is very challenging. To solve this problem, pharmacokinetics/pharmacometabolomics-pharmacodynamics (PK/PM-PD) combined with a multivariate biological correlation-network strategy was developed and applied to a classic MCHF, Baoyuan decoction (BYD), to clarify its active components and synergistic mechanism against cardiac hypertrophy (CH). First, multiple plasma metabolic biomarkers for ß-adrenergic agonist-induced CH rats were identified by using untargeted metabolomic profiling, and then, these CH-associated endogenous metabolites and the absorbed BYD-compounds in plasma at different treatment stages after oral administration of BYD were analyzed by using targeted PK and PM. Second, the dynamic relationship of BYD-related compounds and CH-associated endogenous metabolites and signaling pathways was built by using multivariate and bioinformatic correlation analysis. Finally, metabolic-related PD indicators were predicted and further verified by biological tests. The results demonstrated that the bioavailable BYD-compounds, such as saponins and flavonoids, presented differentiated and distinctive metabolic features and showed positive or negative correlations with various CH-altered metabolites and PD-indicators related to gut microbiota metabolism, amino acid metabolism, lipid metabolism, energy homeostasis, and oxidative stress at different treatment stages. This study provides a novel strategy for investigating the dynamic interaction between BYD and the biosystem, providing unique insight for disclosing the active components and synergistic mechanisms of BYD against CH, which also supplies a reference for other MCHF related research.

The synergistic mechanism of total saponins and flavonoids in Notoginseng-Safflower pair against myocardial ischemia uncovered by an integrated metabolomics strategy.

The Notoginseng-Safflower pair composed of Panax notoginseng (Burk.) F. H. Chen and Carthamus tinctorius L. has remarkable clinical efficacy for preventing and treating cardiovascular diseases in China. Notoginseng total saponins (NS) and Safflower total flavonoids (SF) are the major effective ingredients in Notoginseng and Safflower, respectively. Though our previous study showed that the combination of NS and SF (NS-SF) exhibits significant cardioprotective effects for myocardial ischemia (MI), there might be difference in their action mechanisms. However, the anti-MI characteristics of individual NS and SF remains unclear. Herein, an integrated metabolomics strategy coupled with multiple biological methods were employed to investigate the cardioprotective effects of NS and SF alone or in combination against isoproterenol (ISO)-induced MI and to further explore the synergistic relationship between NS and SF. Our results demonstrated that pretreatments with NS, SF, and NS-SF all showed cardioprotective effects against MI injury and NS-SF exhibited to be the best. Interestingly, the results demonstrated that NS and SF exhibited differentiated metabolic targets and mediators in the glycerophospholipid metabolism. Furthermore, administration of NS alone exhibited greater effects on reversing the elevated the proinflammatory metabolites and mediators in MI rats compared to SF alone. However, individual SF showed greater amelioration of MI-disturbed antioxidant and prooxidative metabolites and better inhibition of the oxidative stress than NS alone. Collectively, our study demonstrated that the capability of NS-SF to regulate both metabolic targets of NS and SF might be the basis of NS-SF to produce a cooperative effect greater than their individual effects that enhance the anti-MI efficacy and provided valuable information for the clinical application of Notoginseng-Safflower pair.

Comparative study on metabolic profiling and excretion in rat bile between combination of notoginseng total saponins and safflower total flavonoids and its individual extracts by LC-MS/MS.

The combination of notoginseng total saponins (NS) and safflower total flavonoids (SF), namely CNS, presents a synergistic protection effect on the myocardial ischemia rats. The aim of this study was to find the clues for their synergistic actions by comparing the biliary metabolism and excretion profiles after oral administration of CNS and its individual extracts. An ultra-performance liquid chromatography coupled with hybrid triple quadrupole-linear ion trap mass spectrometer (UPLC-QTRAP-MS/MS) platform was used to identify and quantify the CNS-derived components in bile. The neutral losses, precursor ions, and predictive multiple reaction monitoring (pMRM) scans were firstly used to detect the CNS-derived ingredients in vivo. A total of 43 components, including 38 flavonoids and 5 ginsenosides were tentatively identified according to the previously established chemical and metabolic profiles of NS and SF. Afterwards, the primary circulating and biological components, hydroxysafflor yellow A (HSYA), ginsenosides Rg1 (GRg1), Re (GRe), and Rd (GRd) were chosen to compare the bile excretion between CNS and its individual extract groups, by using a validated LC-MRM-MS/MS method. The approach was proved to be well satisfied the related requirements from the guidelines of FDA (specificity, calibration curve, sensitivity, precision, accuracy, matrix effect, recovery, and stability). Comparing with the SF and NS groups, the combination group did not affect the metabolic pathways of the CNS-related components, however, it decreased the cumulative excretion ratios of HSYA, GRg1, GRe, and GRd. In conclusion, the compatibility of SF and NS could reduce the bile excretion of the CNS-derived compounds, which may be one of the reasons for the enhancement of anti-myocardial ischemia after combination.

MicroRNA-155 promotes the ox-LDL-induced activation of NLRP3 inflammasomes via the ERK1/2 pathway in THP-1 macrophages and aggravates atherosclerosis in ApoE-/- mice.

BACKGROUND: Nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome activation can induce the secretion of IL-1ß and IL-18 and after promoting the development of atherosclerosis. MiR-155 is an important microRNA that modulates inflammation in atherosclerosis, but the role of miR-155 in the regulation of the NLRP3 inflammasome is still unknown. METHODS: The atherosclerosis model was set up using ApoE-/- mice, and the lentiviral vector (LV) was used to interfere the expression of miR-155. HE stains was used for plaque morphology, immunohistochemistry (IHC) and western blot were used for protein expression quantification. We used oxidized low-density lipoprotein (ox-LDL) to incubate PMA-preprocessed THP-1 macrophages and detected NLRP3 inflammasome activation and ERK1/2 phosphorylation by western blot and Enzyme-linked immunosorbent assay. RESULTS: HE stains showed that the intravascular plaques in the miR-155-up group were remarkably increased, compared with negative control (NC) group. Results of IHC showed that the expression of caspase-1 and IL-1ß in the miR-155-up group was the highest of four groups, consist with the Western blot analysis. The results of in vitro experiment show that ox-LDL promoted NLRP3 inflammasome activation and ERK1/2 phosphorylation. Blocking the ERK1/2 pathway could inhibit ox-LDL-induced NLRP3 inflammasome activation. Moreover, we found that the overexpression of miR-155 promoted the activation of the ox-LDL-induced NLRP3 inflammasome, which could also be blocked by the ERK inhibitor U0126. CONCLUSIONS: MiR-155 aggravates the carotid AS lesion in ApoE-/- mice and exerts a regulatory effect on NLRP3 inflammasome activation in ox-LDL-induced macrophages via the ERK1/2 pathway.

MicroRNA-181a regulates the activation of the NLRP3 inflammatory pathway by targeting MEK1 in THP-1 macrophages stimulated by ox-LDL.

Atherosclerosis (AS) is a chronic inflammatory disease that is characterized by the deposition of lipids in the vascular wall and the formation of foam cells. Macrophages play a critical role in the development of this chronic inflammation. An increasing amount of research shows that microRNAs affect many steps of inflammation. The goal of our study was to investigate the regulatory effect of miR-181a on the NLRP3 inflammasome pathway and explore its possible mechanism. Compared with the control group, the expression of miR-181a was downregulated in the carotid tissue of AS group mice, while the expression of MEK1 and NLRP3-related proteins was upregulated significantly. In vitro, when THP-1 macrophages were stimulated with oxidized low-density lipoprotein (ox-LDL), the expression of miR-181a was decreased, the MEK/ERK/NF-κB inflammatory pathways were activated and the expression of NLRP3 inflammasome-related proteins was upregulated. Exogenous overexpression of miR-181a downregulated the activation of the MEK/ERK/NF-κB pathway and decreased the expression of NLRP3 inflammasome-related proteins (such as NLRP3, caspase-1, interleukin-18 [IL-18], IL-1ß, etc). Exogenous miR-181a knockdown showed the opposite results to those of overexpression group. A luciferase reporter assay proved that miR-181a inhibited the expression of MEK1 by binding to its 3'-untranslated region. When we knocked down miR-181a and then treated cells with U0126 before ox-LDL stimulation, we found that U0126 reversed the increased activation of the MEK/ERK/NF-κB pathway and upregulation of NLRP3 inflammasome-related proteins (NLRP3, caspase-1, IL-18, IL-1ß) that resulted from miR-181a knockdown. Our study suggests that miR-181a regulates the activation of the NLRP3 inflammatory pathway by altering the activity of the MEK/ERK/NF-κB pathway via targeting of MEK1.

LPS induces CXCL16 expression in HUVECs through the miR-146a-mediated TLR4 pathway.

Endothelial inflammation characterizes the early stages of atherosclerosis. CXCL16 is a protein that functions as both a chemokine and adhesion molecule, playing a crucial role in the pathogenesis of atherosclerosis. However, it is uncertain if LPS, a major inducer of inflammation, affects CXCL16 expression in endothelial cells and whether miR-146a, a negative regulator of atherosclerosis, participates in this process. The present study showed that exposure of human umbilical vein endothelial cells (HUVECs) to LPS induced the overexpression of CXCL16, TLR4 and NF-κB, and this induction was blocked by the TLR4 inhibitor TAK-242. In addition, LPS induced the upregulation of miR-146a in HUVECs. Overexpression or inhibition of miR-146a either inhibited or increased the LPS-induced expression CXCL16, TLR4 and NF-κB protein production, respectively. Additionally, miR-146a-induced CXCL16 expression was blocked by TAK-242. Thus, in this study, we demonstrate that LPS stimulates CXCL16 expression via the TLR4/NF-κB signaling pathway, and simultaneously, miR-146 negatively regulates LPS-induced CXCL16 expression through a TLR4-dependent mechanism.

Pharmacokinetics study of 16 representative components from Baoyuan Decoction in rat plasma by LC-MS/MS with a large-volume direct injection method.

BACKGROUND: Baoyuan decoction (BYD), a well-known traditional Chinese medicine (TCM) formula, is clinically used for the treatment of aplastic anemia, chronic renal failure, coronary heart disease, etc. PURPOSE: The purpose of this study was to develop a large-volume direct injection liquid chromatography-mass spectrometry (LC-MS) method for simultaneous determination of 16 representative flavonoids and saponins in rat plasma after oral administration of BYD. METHODS: The rat plasma sample was injected directly into a pre-column, which was eluted firstly by 0.05% formic acid in water. Then, the accumulated components were eluted from the pre-column and transferred into a Waters BEH C18 column with acetonitrile and water system (contain 0.05% formic acid) as the mobile phase at a rate of 0.3 ml/min. The detection was accomplished in a negative mode using the schedule multiple-reaction monitoring (sMRM). RESULTS: The correlation coefficients for calibration curves were all higher than 0.9920 for formononetin, ononin, calycosin, liquiritigenin, isoliquiritigenin, glycyrrhizic acid, glycyrrhetinic acid, liquiritin, isoliquiritin, liquiritin apioside, isoliquiritin apioside, ginsenoside Rb1, ginsenoside Re, ginsenoside Rd, ginsenoside Rg1 and astragaloside. The intra- and inter-day precisions (RSD) and accuracy (RE) for the investigated components were in the range of -10.9 to 13.7%. The average recoveries were in the range of 75.7-108.6%. This method was successfully applied to investigate the pharmacokinetics of 16 compounds of BYD in rats. The absorption and elimination rates of the representative saponins were significantly slower than most of the targeted-flavonoids after oral administration of BYD in rats. CONCLUSION: The results demonstrated that the large-volume direct injection LC-MS method provided a rapid and efficient approach for multi-components pharmacokinetics of TCM.

Comparative Study on Excretive Characterization of Main Components in Herb Pair Notoginseng-Safflower and Single Herbs by LC⁻MS/MS.

The herbal medicine combination of notoginseng-safflower has been commonly used clinically for the prevention and treatment of cardiovascular diseases. A reliable liquid chromatography-tandem mass spectrometry (LC⁻MS/MS) method was developed for simultaneous determination of six bioactive components (hydroxysafflor yellow A, notoginsenoide R1, ginsenoside Rb1, Re, Rd, and Rg1) in rat urine and feces after oral administration of notoginseng total saponins (NS), safflower total flavonoids (SF), and the combination of NS and SF (CNS). The chromatographic separation was achieved on a Waters HSS T3 column under gradient elution with acetonitrile and water containing formic acid as the mobile phase. The calibration curves were linear, with correlation coefficient (r) > 0.99 for six components. The intra- and interday precision (RSD) and accuracy (RE) of QC samples were within -14.9% and 14.9%, respectively. The method was successfully applied to study of the urinary and fecal excretion of six bioactive constituents following oral administration of NS, SF, and CNS in rats. Compared to the single herb, the cumulative excretion ratios of six constituents were decreased in the herbal combination. The study indicated that the combination of notoginseng and safflower could reduce the renal and fecal excretion of the major bioactive constituents and promote their absorption in rats.

Improved Coarray Interpolation Algorithms with Additional Orthogonal Constraint for Cyclostationary Signals.

Many modulated signals exhibit a cyclostationarity property, which can be exploited in direction-of-arrival (DOA) estimation to effectively eliminate interference and noise. In this paper, our aim is to integrate the cyclostationarity with the spatial domain and enable the algorithm to estimate more sources than sensors. However, DOA estimation with a sparse array is performed in the coarray domain and the holes within the coarray limit the usage of the complete coarray information. In order to use the complete coarray information to increase the degrees-of-freedom (DOFs), sparsity-aware-based methods and the difference coarray interpolation methods have been proposed. In this paper, the coarray interpolation technique is further explored with cyclostationary signals. Besides the difference coarray model and its corresponding Toeplitz completion formulation, we build up a sum coarray model and formulate a Hankel completion problem. In order to further improve the performance of the structured matrix completion, we define the spatial spectrum sampling operations and the derivative (conjugate) correlation subspaces, which can be exploited to construct orthogonal constraints for the autocorrelation vectors in the coarray interpolation problem. Prior knowledge of the source interval can also be incorporated into the problem. Simulation results demonstrate that the additional constraints contribute to a remarkable performance improvement.