Vitamin D receptor (VDR) on the cell membrane of mouse macrophages participates in the formation of lipopolysaccharide tolerance: mVDR is related to the effect of artesunate to reverse LPS tolerance.

It is unclear whether membrane vitamin D receptor (mVDR) exists on the macrophage membrane or whether mVDR is associated with lipopolysaccharide (LPS) tolerance. Herein, we report that interfering with caveolae and caveolae-dependent lipid rafts inhibited the formation of LPS tolerance. VDR was detected as co-localized with membrane molecular markers. VDR was detected on the cell membrane and its level was higher in LPS-tolerant cells than that in only LPS treatment cells. Anti-VDR antibodies could abolish the effect of artesunate (AS) to reverse LPS tolerance, and the wild-type peptides (H397 and H305) of VDR, but not the mutant peptide (H397D and H305A), led to the loss of AS's effect. AS decreased the mVDR level in LPS-tolerant cells. In vivo, AS significantly reduced VDR level in the lung tissue of LPS-tolerant mice. In summary, mVDR exists on the cell membrane of macrophages and is closely associated with the formation of LPS tolerance and the effects of AS. Video Abstract.

Artesunate interrupts the self-transcriptional activation of MarA to inhibit RND family pumps of Escherichia coli.

Resistance-Nodulation-Division (RND) family pumps are responsible for producing multidrug resistance in Escherichia coli; however, there has been little study of targeted inhibitors of RNDs. In the present study, we investigated the inhibition of RND pumps by artesunate (AS) in E. coli, and further investigated the mechanism with respect to MarA, a regulator of RNDs. Although AS had no direct antibacterial effect, it showed a synergistic effect in combination with ß-lactams against E. coli ATCC35218 in vitro and in vivo, suggesting it possesses antibacterial enhancement activity. Notably, AS, alone or in combination with ß-lactams, downregulated the mRNA expression levels of marA, soxS, and rob, known as the marA-soxS-rob regulon, which then decreased the expression levels of RNDs, thereby increased ampicillin accumulation within ATCC35218. Using gene-deletion strains, we found that the antibacterial sensitization effect of AS persisted in wildtype bacteria, but was completely lost in the strain lacking marA, and decreased in the strain lacking soxS or rob, suggesting marA plays a crucial role in the sensitization of AS. Critically, we showed that AS inhibited the binding of MarA to the promoter of marA itself, not acrB, resulting in decreased mRNA expression of both acrB and marA. Mechanistically, we found AS directly bound to the central cavity of MarA through the R59 and K62 residues, and thus altered the charge distribution of MarA to interrupt the recognition between MarA and its promoter. We concluded that AS interrupts the self-transcriptional activation of MarA, thereby inhibits MarA-dependent mRNA expression of marA, acrAB, and tolC, and also certain other RNDs and regulatory genes related to MarA. Therefore, AS is a novel inhibitor of RND pumps that acts on the regulator MarA.

Iron-Catalyzed Radical Relay Enabling the Modular Synthesis of Fused Pyridines from Alkyne-Tethered Oximes and Alkenes.

We have rationally designed a new class of alkyne-tethered oximes and applied them in an unprecedented iron-catalyzed radical relay protocol for the rapid assembly of a wide array of structurally new and interesting fused pyridines. This method shows broad substrate scope and good functional-group tolerance and enabled the synthesis of several biologically active molecules. Furthermore, the fused pyridines could be diversely functionalized through various simple transformations, such as cyclization, C-H alkylation, and a click reaction. DFT calculation studies indicate that the reactions involve cascade 1,5-hydrogen atom transfer, 5-exo-dig radical addition, and cyclization processes. Moreover, preliminary biological investigations suggest that some of the fused pyridines exhibit good anti-inflammatory activity by restoring the imbalance of inflammatory homeostasis of macrophages in a lipopolysaccharide-induced model.

Dual Role of Triptolide in Interrupting the NLRP3 Inflammasome Pathway to Attenuate Cardiac Fibrosis.

In a previous paper, we reported that triptolide (TP), a commonly used immunomodulator, could attenuate cardiac hypertrophy. This present study aimed to further explore the inhibition of cardiac fibrosis by TP and the possible mechanism from the perspective of the NOD-like receptor protein 3 (NLRP3) inflammasome. Hematoxylin-eosin and Masson's staining, immunohistochemistry, and immunofluorescence were performed to observe cardiac fibrotic changes in mice and mouse cardiac fibroblasts (CFs). The Western blot, colocalization, and immunoprecipitation were applied to detect protein expression and interactions. Results suggested that TP dose-dependently inhibited cardiac fibrosis induced by isoproterenol and collagen production of CFs induced by angiotensin II. TP exhibited an antifibrotic effect via inhibiting activation of the NLRP3 inflammasome, which sequentially decreased IL-1ß maturation, myeloid differentiation factor 88 (MyD88)-related phosphorylation of c-Jun N-terminal kinase (JNK), extracellular regulated protein kinase 1/2 (ERK1/2), and TGF-ß1/Smad signaling, and ultimately resulted in less collagen production. Moreover, TP showed no antifibrotic effect in Nlrp3-knockout CFs. Notably, TP inhibited the expression of NLRP3 and apoptosis-associated speck-like proteins containing a caspase recruitment domain (ASC) as well as inflammasome assembly, by interrupting the NLRP3-ASC interaction to inhibit inflammasome activation. Finally, TP indeed inhibited the NLRP3-TGFß1-Smad pathway in vivo. Conclusively, TP was found to play a dual role in interrupting the activation of the NLRP3 inflammasome to attenuate cardiac fibrosis.

Artesunate Attenuates Pro-Inflammatory Cytokine Release from Macrophages by Inhibiting TLR4-Mediated Autophagic Activation via the TRAF6-Beclin1-PI3KC3 Pathway.

BACKGROUND/AIMS: Lipopolysaccharide (LPS) plays a critical role in excessive inflammatory cytokine production during sepsis. Previously, artesunate (AS) was reported to protect septic mice by reducing LPS-induced pro-inflammatory cytokine release. In the present study, the possible mechanism of the anti-inflammatory effect of AS was further investigated. METHODS: An enzyme-linked immunosorbent assay was used to detect TNF-α and IL-6 release from macrophages. Specific small interfering RNAs (siRNAs) were used to knockdown the mRNA expression of target genes. Transmission electron microscopy and laser confocal microscopy were used to observe changes in autophagy. Western blotting was performed to detect the protein levels of tumor necrosis factor receptor-associated factor6 (TRAF6), Beclin1, phosphatidylinositol 3-kinase class III (PI3KC3), autophagy-related protein 5 (ATG5), and sequestosome 1. Immunoprecipitation (IP) and fluorescent co-localization were used to detect the interactions between TRAF6-Beclin1 and Beclin1-PI3KC3, and the ubiquitination of Beclin1. RESULTS: AS inhibited TNF-α and IL-6 release from RAW264.7 cells, mouse bone marrow-derived monocytes (BMDMs) and peritoneal macrophages (PMs) induced by LPS. However, the inhibition by AS of LPS-induced cytokine release decreased when autophagy was inhibited using 3-MA, bafilomycin A1, or a siRNA targeting the Atg5 gene. Notably, AS showed an inhibition of LPS-induced autophagic activation not degradation. Whereas, these effects of AS were lost in macrophages lacking TLR4 and decreased in macrophages with down-regulated TRAF6, indicating that AS inhibited LPS-induced cytokine release and autophagic activation via TLR4-TRAF6 signaling. Western blotting results showed AS could reduce the levels of TRAF6, Beclin1, and PI3KC3. Importantly, the IP results showed AS only inhibited K63-linked ubiquitylation not total ubiquitylation of Beclin1 by acting on TRAF6. This interrupted the TRAF6-Beclin1 interaction and subsequent the formation of Beclin1- PI3KC3 core complex of the PI3K-III complex. CONCLUSION: AS inhibited LPS-induced cytokine release from macrophages by inhibiting autophagic activation. This effect was tightly related to blockade of the TRAF6-Beclin1-PI3KC3 pathway via decreasing K63-linked ubiquitination of Beclin1 and then interrupting the formation of Beclin1-PI3KC3 core complex of the PI3K-III complex. Our findings reveal the mechanism of AS's anti-inflammatory effect and is significant for future targeted investigations of sepsis treatment.

Cyclin-Dependent Kinase Inhibitor p21WAF1/CIP1 Facilitates the Development of Cardiac Hypertrophy.

BACKGROUND/AIMS: Adult cardiomyocytes can re-enter cell cycle as stimulated by prohypertrophic factors although they withdraw from cell cycle soon after birth. p21WAF1/CIP1, a cyclin-dependent kinase inhibitor, has been implicated in cardiac hypertrophy, however, its precise contribution to this process remains largely unclear. METHODS: The gene expression profile in left ventricle (LV) of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats was determined using quantitative PCR array and verified by real-time PCR and Western blotting. Hypertrophic response of H9c2 cells and neonatal rat ventricular myocytes (NRVM) were induced by angiotensin II (1 µmol/L). Cardiac hypertrophy of mice was elicited by isoproterenol (ISO) infusion (40 mg/kg per day for 14 days). p21-adenovirus and p21-siRNA were employed to transfect NRVM, and sterigmatocystin (STE, 3 mg/kg, ip, qd) was used to inhibit p21 activity. mRNA and protein expression levels of α- and ß-myosin heavy chain (MHC), p21WAF1/CIP1, calcineurin (CaN) and atrial natriuretic peptide (ANP) were assayed by realtime PCR and WB, respectively. RESULTS: Sixteen genes showed two-fold or greater changes between SHR and WKY rats, in which the expression of p21WAF1/CIP1 was upregulated by 4.15-fold (P=0.002) and reversed by losartan. Surface area, protein content, mRNA and protein expressions of ß-MHC, ANP and p21WAF1/CIP1 in H9c2 cells treated with AngII elevated significantly compared with control group. p21-Ad transfection markedly increased the surface area and ß-MHC mRNA expression of normal NRVMs, and p21-siRNA transfection decreased them in AngII-treated NRVMs. STE treatment decreased HW/BW and cross-sectional area, expression levels of ß-MHC, ANP and p21 significantly in ISO-treated mice. CONCLUSION: Our findings suggest that p21 facilitates the development of cardiac hypertrophy, and regulating the expression of p21 may be an approach to attenuate hypertrophic growth of cardiomyocytes.

Synthetic Human TLR9-LRR11 Peptide Attenuates TLR9 Signaling by Binding to and thus Decreasing Internalization of CpG Oligodeoxynucleotides.

Toll-like receptor (TLR) 9 is an endosomal receptor recognizing bacterial DNA/CpG-containing oligodeoxynucleotides (CpG ODN). Blocking CpG ODN/TLR9 activity represents a strategy for therapeutic prevention of immune system overactivation. Herein, we report that a synthetic peptide (SP) representing the leucine-rich repeat 11 subdomain of the human TLR9 extracellular domain could attenuate CpG ODN/TLR9 activity in RAW264.7 cells by binding to CpG ODN and decreasing its internalization. Our results demonstrate that preincubation with SP specifically inhibited CpG ODN- but not lipopolysaccharide (LPS)- and lipopeptide (PAM3CSK4)-stimulated TNF-α and IL-6 release. Preincubation of SP with CpG ODN dose-dependently decreased TLR9-driven phosphorylation of IκBα and ERK and activation of NF-κB/p65. Moreover, SP dose-dependently decreased FAM-labeled CpG ODN internalization, whereas non-labeled CpG ODN reversed the inhibition. The KD value of SP-CpG ODN binding was within the micromolar range. Our results demonstrated that SP was a specific inhibitor of CpG ODN/TLR9 activity via binding to CpG ODN, leading to reduced ODN internalization and decreased activation of subsequent pathways within cells. Thus, SP could be used as a potential CpG ODN antagonist to block TLR9 signaling.

Design of New Antibacterial Enhancers Based on AcrB's Structure and the Evaluation of Their Antibacterial Enhancement Activity.

Previously, artesunate (AS) and dihydroartemisinine 7 (DHA7) were found to have antibacterial enhancement activity against Escherichia coli via inhibition of the efflux pump AcrB. However, they were only effective against E. coli standard strains. This study aimed to develop effective antibacterial enhancers based on the previous work. Our results demonstrate that 86 new antibacterial enhancers were designed via 3D-SAR and molecular docking. Among them, DHA27 had the best antibacterial enhancement activity. It could potentiate the antibacterial effects of ampicillin against not only E. coli standard strain but also clinical strains, and of ß-lactam antibiotics, not non-ß-lactamantibiotics. DHA27 could increase the accumulation of daunomycin and nile red within E. coli ATCC 35218, but did not increase the bacterial membrane permeability. DHA27 reduced acrB's mRNA expression of E. coli ATCC 35218 in a dose-dependent manner, and its antibacterial enhancement activity is related to the degree of acrB mRNA expression in E. coli clinical strains. The polypeptides from AcrB were obtained via molecular docking assay; the pre-incubated polypeptides could inhibit the activity of DHA27. Importantly, DHA27 had no cytotoxicity on cell proliferation. In conclusion, among newly designed antibacterial enhancers, DHA27 had favorable physical and pharmacological properties with no significant cytotoxicity at effective concentrations, and might serve as a potential efflux pump inhibitor in the future.

The direct anti-MRSA effect of emodin via damaging cell membrane.

Methicillin-resistant Staphylococcus aureus (MRSA) has become an important bacterium for nosocomial infection. Only a few antibiotics can be effective against MRSA. Therefore, searching for new drugs against MRSA is important. Herein, anti-MRSA activities of emodin and its mechanisms were investigated. Firstly, in vitro antimicrobial activity was investigated by minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-growth curve, and multipassage resistance testing was performed. Secondly, protection of emodin on mice survival and blood bacterial load in mice challenged with lethal or sublethal dose of MRSA were investigated. Subsequently, the influences of emodin on the bacterial morphology, messenger RNA (mRNA) expressions related to cell wall synthesis and lysis, ß-lactamase activity, drug accumulation, membrane fluidity, and integrity were performed to investigate its mechanisms. Lastly, in vitro cytotoxicity assay were performed using the 3-(4,5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) method. The results showed MICs and MBCs of emodin against MRSA252 and 36 clinical MRSA strains were among 2-8 and 4-32 µg/mL, respectively. There was no MIC increase for emodin during 20 passages. In vivo, emodin dose-dependently protected mice challenged with lethal dose of MRSA and decreased bacterial load in mice challenged with sublethal dose of MRSA. Morphology observation showed emodin might disrupt cell wall and membrane of MRSA. Although emodin had no influence on genes related to cell wall synthesis and lysis as well as ß-lactamase activity and drug accumulation, emodin reduced membrane fluidity and disrupted membrane integrity. Based on the fact that emodin had no significant cytotoxicity against mammalian cells, it could be further investigated as a membrane-damage bactericide against MRSA in the future.

Emodin is identified as the active component of ether extracts from Rhizoma Polygoni Cuspidati, for anti-MRSA activity.

This study investigated the anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activity and chemical compositions of ether extracts from Rhizoma Polygoni Cuspidati (ET-RPC). Significant anti-MRSA activities of ET-RPC against MRSA252 and MRSA clinical strains were tested in in vitro antibacterial experiments, such as inhibition zone diameter test, minimal inhibitory concentration test, and dynamic bacterial growth assay. Subsequently, 7 major compounds of ET-RPC were purified and identified as polydatin, resveratrol-4-O-d-(6'-galloyl)-glucopyranoside, resveratrol, torachryson-8-O-glucoside, emodin-8-O-glucoside, 6-hydroxy-emodin, and emodin using liquid chromatography - electrospray ionization - tandem mass spectrometry. After investigation of anti-MRSA activities of the 7 major compounds, only emodin had significant anti-MRSA activity. Further, transmission electron microscopy was used to observe morphological changes in the cell wall of MRSA252, and the result revealed that emodin could damage the integrity of cell wall, leading to loss of intracellular components. In summary, our results showed ET-RPC could significantly inhibit bacterial growth of MRSA strains. Emodin was identified as the major compound with anti-MRSA activity; this activity was related to destruction of the integrity of the cell wall and cell membrane.

Artesunate reduces serum lipopolysaccharide in cecal ligation/puncture mice via enhanced LPS internalization by macrophages through increased mRNA expression of scavenger receptors.

Innate immunity is the first line of defense in human beings against pathogen infection; monocytes/macrophages are the primary cells of the innate immune system. Recently, macrophages/monocytes have been discovered to participate in LPS clearance, and the clearance efficiency determines the magnitude of the inflammatory response and subsequent organ injury. Previously, we reported that artesunate (AS) protected sepsis mice against heat-killed E. coli challenge. Herein, we further confirmed that AS protected cecal ligation/puncture (CLP) sepsis mice. Its protection on sepsis mice was related to not only reduction of pro-inflammatory cytokines and serum LPS levels but also improvement of liver function. Based on the fact that AS did not directly bind and neutralize LPS, we hypothesized that the reduction of serum LPS level might be related to enhancement of LPS internalization and subsequent detoxification. Our results showed that AS increased FITC-LPS internalization by peritoneal macrophage and liver Kupffer cell, but enhancement of LPS internalization by AS was not related to the clathrin-dependent pathway. However, AS induced mRNA expression of important scavenger receptors (SRs); SR-A and MARCO mRNA expression was upregulated, suggesting that AS enhancement of LPS internalization and inhibition of pro-inflammatory cytokines was related to changes in mRNA expression of SRs.

Modular Assembly of 2-Aminoaniline Derivatives by Merging Hydroxylamine-Passerini and Hetero-Cope Rearrangement.

A metal-free three-component protocol that combines a hydroxylamine-Passerini reaction and hetero-Cope rearrangement was realized, which enables the modular assembly of a wide range of structurally new and interesting 2-aminoanilines bearing an α-hydroxyamide substructure.

Leucine-rich repeat 11 of Toll-like receptor 9 can tightly bind to CpG-containing oligodeoxynucleotides, and the positively charged residues are critical for the high affinity.

TLR9 is a receptor for sensing bacterial DNA/CpG-containing oligonucleotides (CpG ODN). The extracellular domain (ECD) of human TLR9 (hTLR9) is composed of 25 leucine-rich repeats (LRR) contributing to the binding of CpG ODN. Herein, we showed that among LRR2, -5, -8, and -11, LRR11 of hTLR9 had the highest affinity for CpG ODN followed by LRR2 and -5, whereas LRR8 had almost no affinity. In vitro, preincubation with LRR11 more significantly decreased CpG ODN internalization, subsequent NF-κB activation, and cytokine release than with LRR2 and -5 in mouse peritoneal macrophages treated with CpG ODN. The LRR11 deletion mutant of hTLR9 conferred decreased cellular responses to CpG ODN. Single- or multiple-site mutants at five positively charged residues of LRR11 (LRR11m1-9), especially Arg-337 and Lys-367, were shown to contribute to hTLR9 binding of CpG ODN. LRR11m1-9 showed reduced inhibition of CpG ODN internalization and CpG ODN/TLR9 signaling, supporting the above findings. Prediction of whole hTLR9 ECD-CpG ODN interactions revealed that Arg-337 and Lys-338 directly contact CpG ODN through hydrogen bonding, whereas Lys-347, Arg-348, and His-353 contribute to stabilizing the shape of the ligand binding region. These findings suggested that although all five positively charged residues within LRR11 contributed to its high affinity, only Arg-337 and Lys-338 directly interacted with CpG ODN. In conclusion, the results suggested that LRR11 could strongly bind to CpG ODN, whereas mutations at the five positively charge residues reduced this high affinity. LRR11 may be further investigated as an antagonist of hTLR9.

Toll-like receptor 9 interaction with CpG ODN--an in silico analysis approach.

BACKGROUND: Toll-like receptor 9 (TLR9) recognises unmethylated CpG DNA and activates a signalling cascade, leading to the production of inflammatory cytokines such as TNF-α, IL-1, IL-6 and IL-12 via the adaptor protein MyD88. However, the specific sequence and structural requirements of the CpG DNA for the recognition of and binding to TLR9 are unknown. Moreover, the 3D structures of TLR9 and the TLR9-ODN complex have not been determined. In this study, we propose a reliable model of the interaction of the TLR9 ECD with CpG ODN using bioinformatics tools. RESULTS: The three-dimensional structures of two TLR9 ECD-CpG ODN complexes were constructed using a homology modelling and docking strategy. Based on the models of these complexes, the TLR9 ECD-CpG ODN interaction patterns were calculated. The results showed that the interface between the human TLR9 and the CpG ODN molecule is geometrically complementary. The computed molecular interactions indicated that LRR11 is the main region of TLR9 that binds to CpG ODN and that five positively charged residues within LRR11 are involved in the binding of the TLR9 ECD to the CpG ODN. Observations in the close-up view of these interactions indicated that these five positively charged residues contribute differently to the binding region within the TLR9 ECD-CpG ODN complex. 337Arg and 338Lys reside in the binding sites of ODN, forming hydrogen bonds and direct contacts with the CpG ODN, whereas 347Lys, 348Arg, and 353His do not directly contact the CpG ODN. These results are in agreement with previously reported experimental data. CONCLUSION: In this study, we present two structural models for the human and mouse TLR9 ECD in a complex with CpG ODN. Some features predicted by this model are consistent with previously reported experimental data. This complex model may lead to a better understanding of the function of TLR9 and its interaction with CpG ODN and will improve our understanding of TLR9-ligand interaction in general.

Design, synthesis and evaluation of the antibacterial enhancement activities of amino dihydroartemisinin derivatives.

Artemisinin (ART) and its derivatives artesunate (AS), dihydroartemisinin (DHA) are a group of drugs containing a sesquiterpene lactone used to treat malaria. Previously, AS was shown to not have antibacterial activity but to significantly increase the antibacterial activities of ß-lactam antibiotics against E. coli. Herein, molecular docking experiments showed that ART, AS and DHA could dock into AcrB very well, especially DHA and AS; both DHA and AS had the same docking pose. The affinity between AS and AcrB seemed weaker than that of DHA, while the succinate tail of AS, which was like a "bug", could extend in the binding pocket very well. Imitating the parent nucleus of DHA and the succinate tail of AS, twenty-one DHA derivatives 4a-u were designed and synthesized. Among them, seventeen were new compounds. The synergistic effects against E. coli AG100A/pET28a-AcrB showed among the new structures 4k, 4l, 4m, 4n, and 4r exhibited significant synergism with ß-lactam antibiotics although they had no direct antibacterial activities themselves. The bacterial growth assay showed that only 4k in combination with ampicillin or cefuroxime could totally inhibit bacterial growth from 0 to 12 h, demonstrating that 4k had the best antibacterial enhancement effect. In conclusion, our results provided a new idea and several candidate compounds for antibacterial activity enhancers against multidrug resistant E. coli.

Anti-malarial artesunate ameliorates atherosclerosis by modulating arterial inflammatory responses via inhibiting the NF-κB-NLRP3 inflammasome pathway.

Introduction: Chronic inflammation plays a critical role in the pathogenesis of atherosclerosis (AS), and involves a complex interplay between blood components, macrophages, and arterial wall. Therefore, it is valuable in the development of targeted therapies to treat AS. Methods: AS rat model was induced by atherogenic diet plus with lipopolysaccharide (LPS) and then treated by anti-malarial artesunate (Art), a succinate derivative of artemisinin. The arterial morphology was observed after Oil red O, hematoxylin-eosin, and Masson's staining. The arterial protein level was detected by immunohistochemistry or immunofluorescence. The expression level of mRNA was determined by PCR array or real-time PCR. Results: Herein, we showed that Art possessed a dose-dependently protective effect on AS rats. In detail, Art showed a comparable inhibitory effect on arterial plaque and serum lipids compared to those of rosuvastatin (RS), and further showed a better inhibition on arterial lipid deposition and arterial remodeling comprised of arterial wall thicken and vascular collagen deposition, than those of RS. The improvement of Art on AS rats was related to inhibit arterial macrophage recruitment, and inhibit nuclear factor κB (NF-κB)-related excessive arterial inflammatory responses. Critically, Art showed significant inhibition on the NLRP3 inflammasome activation in both arterial wall and arterial macrophages, by down-regulating the expression of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and apoptosis associated speckle-like protein containing CARD (ASC), leading to less production of the NLRP3 inflammasome-derived caspase-1, interleukin-1ß (IL-1ß), IL-18, and subsequent transforming growth factor ß1 (TGF-ß1) in AS rats. Conclusion: We propose that Art is an anti-AS agent acts through modulating the arterial inflammatory responses via inhibiting the NF-κB - NLRP3 inflammasome pathway.

The Chinese Herbal Formula Huoxiang Zhengqi Dropping Pills Prevents Acute Intestinal Injury Induced by Heatstroke by Increasing the Expression of Claudin-3 in Rats.

Intestinal injury has been regarded as an important causative factor for systemic inflammation during heatstroke, and maintaining intestinal integrity has been a potential target for the prevention of HS. Huoxiang Zhengqi Dropping Pills (HZPD) is a modern preparation of Huoxiang Zhengqi and widely used to prevent HS. The present study aims to explore the protective effect of HZDP on intestinal injury during heatstroke and analyze its potential pharmacodynamic basis. Male rats in the control and HS groups were given normal saline, and those in the HZDP groups were given HZDP (0.23, 0.46, and 0.92 g/kg) before induction of HS. Serum contents of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), intestinal fatty acid-binding protein (iFABP), and diamine oxidase (DAO) were determined using ELISA. Histopathology of intestinal injury was observed following H&E staining. The expression of claudin-3 was determined using western blot, immunohistochemistry, and immunofluorescence techniques. Moreover, network pharmacological tools were used to analyze the potential pharmacodynamic basis and the mechanism of HZDP. Treatment with HZDP significantly prolonged the time to reach Tc. Compared with the control group, the contents of TNF-α, IL-6, iFABP, and DAO in HS rats increased markedly. HZDP treatments reduced these levels significantly, and the effects in the middle dose group (0.46 g/kg) were most obvious. HZDP also attenuated intestinal injury and significantly reversed the decrease in claudin-3 expression. Bioinformatics analysis suggested that 35 active ingredients and 128 target genes of HZDP were screened from TCMSP and 93 target genes intersected with heatstroke target genes, which were considered potential therapeutic targets. TNF-α and IL-6 were the main inflammatory target genes of HZDP correlated with HS. These results indicated that HZDP effectively protected intestinal barrier function and prevented acute intestinal injury by increasing the expression of claudin-3 in rats, eventually improving heat resistance.

Self-limiting bidirectional positive feedback between P53 and P21 is involved in cardiac hypertrophy.

Pathological cardiac hypertrophy is an independent risk factor of cardiovascular diseases. Although the function of p53 and p21 in pathological cardiac hypertrophy have been studied, the relationship between them in cardiomyocytes is still unclear. By using specific adenoviruses and siRNAs to modulate p53 or p21 expression in neonatal rat ventricular myocytes (NRVMs), we found that both upregulated p53 and p21 expression induced hypertrophic responses, and they promote each other's expression. Overexpression of p53 aggravated the hypertrophic response of cardiomyocytes in vitro and in vivo, while knockdown of p21 diminished the hypertrophic responses induced by angiotensin Ⅱ and the increase of p53 expression. Additionally, Angiotensin Ⅱ treatment promoted the nuclear translocation of p21 in NRVMs. Notably, increased p53 expression alone did not promote p21 translocation to the nucleus. Together, these data suggest a self-limiting bidirectional positive feedback interaction between p53 and p21 during cardiac hypertrophy.

Cardiomyocytic FoxP3 is involved in Parkin-mediated mitophagy during cardiac remodeling and the regulatory role of triptolide.

Rationale: Forkhead/winged helix transcriptional factor P3 (FoxP3) is a well-studied transcription factor that maintains the activity of T cells, but whether cardiomyocytic FoxP3 participates in cardiac remodeling (CR) remains unclear. The present study was to investigate the role of cardiomyocytic FoxP3 in CR from the perspective of mitophagy. Methods: CR was induced by angiotensin II (AngII) in vitro, or by isoproterenol (Iso) in vivo using male C57 mice or FoxP3DTR mice. Histological changes were observed by hematoxylin-eosin and Masson staining. Molecular changes were detected by immunohistochemistry, immunofluorescence, immunoblotting, and real-time PCR. Mitophagy was shaped by transmission electron microscopy and co-localization. The mRNA expression was operated by siRNA or adeno associated virus (AAV). Molecular interactions were detected by co-localization, immunoprecipitation (IP), and chromatin IP. Results: The expression and nuclear translocation of cardiomyocytic FoxP3 were downregulated in CR, while they were upregulated after triptolide (TP) treatment. In left ventricle (LV) remodeling in mice, autophagy was activated continuously in the myocardium, and TP significantly attenuated it. AngII induced massive mitophagy characterized by the activation of autophagy regulatory protein 5 (Atg5)-dependent autophagic flux. Critically, Parkin was identified as the main adaptor mediated myocardial mitophagy and was responsible for the effect of TP. Moreover, FoxP3 was responsible for the downregulation of Parkin and inhibited AngII-induced cardiac mitophagy. We found that mitophagy increased significantly and the inhibition of TP treatment reversed completely in FoxP3-deficient LVs. Mechanistically, FoxP3 interacted with a motif located downstream of the activating transcription 4 (ATF4)-binding motif involved in the promoter of Parkin and hijacked free nuclear ATF4 to decrease Parkin mRNA expression in CR. Conclusion: Cardiomyocytic FoxP3 could negatively regulate Parkin-mediated mitophagy in CR, and restoring cardiomyocytic FoxP3 activity provided a cardioprotective strategy by inhibiting excessive cardiac mitophagy.