Inhibition of HDAC6 attenuates LPS-induced inflammation in macrophages by regulating oxidative stress and suppressing the TLR4-MAPK/NF-κB pathways

A novel HDAC6 inhibitor attenuate APAP-induced liver injury by regulating MDH1-mediated oxidative stress

Glutathione (GSH) depletion, mitochondrial damage, and oxidative stress have been implicated in the pathogenesis of acetaminophen (APAP) hepatotoxicity. Here, we demonstrated that the expression of histone deacetylase 6 (HDAC6) is highly elevated, whereas malate dehydrogenase 1 (MDH1) is downregulated in liver tissues and AML-12 cells induced by APAP. The therapeutic benefits of LT-630, a novel HDAC6 inhibitor on APAP-induced liver injury, were also substantiated. On this basis, we demonstrated that LT-630 improved the protein expression and acetylation level of MDH1. Furthermore, after overexpression of MDH1, an upregulated NADPH/NADP+ ratio and GSH level and decreased cell apoptosis were observed in APAP-stimulated AML-12 cells. Importantly, MDH1 siRNA clearly reversed the protection of LT-630 on APAP-stimulated AML-12 cells. In conclusion, LT-630 could ameliorate liver injury by modulating MDH1-mediated oxidative stress induced by APAP.

BMSC Alleviates Dry Eye by Inhibiting the ROS-NLRP3-IL-1β Signaling Axis by Reducing Inflammation Levels

PURPOSE

Bone marrow mesenchymal stem cells (BMSC) have multiple biological functions and are widely involved in regulating inflammatory diseases, tissue repair and regeneration. However, the mechanism of their action in dry eye disease (DED) is currently unclear. The purpose of this study was to investigate the effect of BMSCs in the treatment of dry eye mice and to explore its specific therapeutic mechanism.

METHODS

Mouse corneal epithelial cells (MCECs) were treated with 500 mOsM sodium chloride hypertonic solution to induce a DED cell model. The dry eye animal model was constructed by adding 5 μL 0.2% benzalkonium chloride solution to mouse eyes. Western blotting was used to detect the expression of related proteins, and flow cytometry, enzyme-linked immunosorbent assay (ELISA), terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining, hematoxylin-eosin (HE) staining, and periodic acid schiff (PAS) staining were used to detect cell and eye tissue damage.

RESULTS

The experimental results showed that BMSCs can reduce the levels of reactive oxygen species (ROS) and inflammatory factors in MCECs, promote cell proliferation, inhibit cell apoptosis, improve the integrity of the corneal epithelial layer in vivo, promote an increase in the number of goblet cells, and alleviate DED. Further exploration of the molecular mechanism of BMSCs treatment revealed that BMSCs alleviate the progression of DED by inhibiting the ROS-NLRP3-IL-1β signaling pathway.

CONCLUSION

BMSCs inhibit ROS-NLRP3-IL-1β signaling axis, reducing inflammation levels and alleviating dry eye symptoms. These findings provide new ideas and a basis for the treatment of DED and provide an experimental basis for further research on the application value of BMSCs in alleviating DED.

Zinc glycinate alleviates LPS-induced inflammation and intestinal barrier disruption in chicken embryos by regulating zinc homeostasis and TLR4/NF-κB pathway

The effect of an immune challenge induced by a lipopolysaccharide (LPS) exposure on systemic zinc homeostasis and the modulation of zinc glycinate (Zn-Gly) was investigated using a chicken embryo model. 160 Arbor Acres broiler fertilized eggs were randomly divided into 4 groups: CON (control group, injected with saline), LPS (LPS group, injected with 32 µg of LPS saline solution), Zn-Gly (zinc glycinate group, injected with 80 µg of zinc glycinate saline solution) and Zn-Gly+LPS (zinc glycinate and LPS group, injected with the same content of zinc glycinate and LPS saline solution). Each treatment consisted of eight replicates of five eggs each. An in ovo feeding procedure was performed at 17.5 embryonic day and samples were collected after 12 hours. The results showed that Zn-Gly attenuated the effects of LPS challenge-induced upregulation of pro-inflammatory factor interleukin 1β (IL-1β) level (P =0.003). The LPS challenge mediated zinc transporter proteins and metallothionein (MT) to regulate systemic zinc homeostasis, with increased expression of the jejunum zinc export gene zinc transporter protein 1 (ZnT-1) and elevated expression of the import genes divalent metal transporter 1 (DMT1), Zrt- and Irt-like protein 3 (Zip3), Zip8 and Zip14 (P < 0.05). A similar trend could be observed for the zinc transporter genes in the liver, which for ZnT-1 mitigated by Zn-Gly supplementation (P =0.01). Liver MT gene expression was downregulated in response to the LPS challenge (P =0.004). These alterations caused by LPS resulted in decreased serum and liver zinc levels and increased small intestinal, muscle and tibial zinc levels. Zn-Gly reversed the elevated expression of the liver zinc finger protein A20 induced by the LPS challenge (P =0.025), while Zn-Gly reduced the gene expression of the pro-inflammatory factors IL-1β and IL-6, decreased toll-like receptor 4 (TLR4) and nuclear factor kappa-B p65 (NF-κB p65) (P < 0.05). Zn-Gly also alleviated the LPS-induced downregulation of the intestinal barrier gene Claudin-1. Thus, LPS exposure prompted the mobilization of zinc transporter proteins and MT to perform the remodeling of systemic zinc homeostasis, Zn-Gly participated in the regulation of zinc homeostasis and inhibited the production of pro-inflammatory factors through the TLR4/NF-κB pathway, attenuating the inflammatory response and intestinal barrier damage caused by an immune challenge.

Supplementation of nicotinamide mononucleotide diminishes COX-2 associated inflammatory responses in macrophages by activating kynurenine/AhR signaling

Cyclooxygenase-2 (COX-2) is an inducible enzyme responsible for prostaglandin synthesis during inflammation and immune responses. Our previous results show that NAD+ level decreased in activated macrophages while nicotinamide mononucleotide (NMN) supplementation suppressed the inflammatory responses via restoring NAD+ level and downregulating COX-2. However, whether NMN downregulates COX-2 in mouse model of inflammation, and its underlying mechanism needs to be further explored. In the present study, we established LPS- and alum-induced inflammation model and demonstrated that NMN suppressed the inflammatory responses in vivo. Quantitative proteomics in mouse peritoneal macrophages identified that NMN activated AhR signaling pathway in activated macrophages. Furthermore, we revealed that NMN supplementation led to IDO1 activation and kynurenine accumulation, which caused AhR nuclear translocation and activation. On the other hand, AhR or IDO1 knockout abolished the effects of NMN on suppressing COX-2 expression and inflammatory responses in macrophages. In summary, our results demonstrated that NMN suppresses inflammatory responses by activating IDO-kynurenine-AhR pathway, and suggested that administration of NMN in early-stage immuno-activation may cause an adverse health effect.

Histone deacetylase 6 deficiency protects the liver against ischemia/reperfusion injury by activating PI3K/AKT/mTOR signaling

Liver transplantation (LT) is the only effective method to treat end-stage liver disease. Hepatic ischemia-reperfusion injury (IRI) continues to limit the prognosis of patients receiving LT. Histone deacetylase 6 (HDAC6) is a unique HDAC member involved in inflammation and apoptosis. However, its role and mechanism in hepatic IRI have not yet been reported. We examined HDAC6 levels in liver tissue from LT patients, mice challenged with liver IRI, and hepatocytes subjected to hypoxia/reoxygenation (H/R). In addition, HDAC6 global-knockout (HDAC6-KO) mice, adeno-associated virus-mediated liver-specific HDAC6 overexpressing (HDAC6-LTG) mice, and their corresponding controls were used to construct hepatic IRI models. Hepatic histology, inflammatory responses, and apoptosis were detected to assess liver injury. The molecular mechanisms of HDAC6 in hepatic IRI were explored in vivo and in vitro. Moreover, the HDAC6-selective inhibitor tubastatin A was used to detect the therapeutic effect of HDAC6 on liver IRI. Together, our results showed that HDAC6 expression was significantly upregulated in liver tissue from LT patients, mice subjected to hepatic I/R surgery, and hepatocytes challenged by hypoxia/reoxygenation (H/R) treatment. Compared with control mice, HDAC6 deficiency mitigated liver IRI by inhibiting inflammatory responses and apoptosis, whereas HDAC6-LTG mice displayed the opposite phenotype. Further molecular experiments show that HDAC6 bound to and deacetylated AKT and HDAC6 deficiency improved liver IRI by activating PI3K/AKT/mTOR signaling. In conclusion, HDAC6 is a key mediator of hepatic IRI that functions to promote inflammation and apoptosis via PI3K/AKT/mTOR signaling. Targeting hepatic HDAC6 inhibition may be a promising approach to attenuate liver IRI.

HDAC6-MYCN-CXCL3 axis mediates allergic inflammation and is necessary for allergic inflammation-promoted cellular interactions

Histone deacetylase 6 (HDAC6) has been shown to play an important role in allergic inflammation. This study hypothesized that novel downstream targets of HDAC6 would mediate allergic inflammation. Experiments employing HDAC6 knock out C57BL/6 mice showed that HDAC6 mediated passive cutaneous anaphylaxis (PCA) and passive systemic anaphylaxis (PSA). Antigen stimulation increased expression of N-myc (MYCN) and CXCL3 in an HDAC6-dependent manner in the bone marrow-derived mast cells. MYCN and CXCL3 were necessary for both PCA and PSA. The role of early growth response 3 (EGR3) in the regulation of HDAC6 expression has been reported. ChIP assays showed EGR3 as a direct regulator of MYCN. miR-34a-5p was predicted to be a negative regulator of MYCN. Luciferase activity assays showed miR-34a-5p as a direct regulator of MYCN. miR-34a-5p mimic negatively regulated PCA and PSA. MYCN decreased miR-34a-5p expression in antigen-stimulated rat basophilic leukemia cells (RBL2H3). MYCN was shown to bind to the promoter sequence of CXCL3. In an IgE-independent manner, recombinant CXCL3 protein increased expression of HDAC6, MYCN, and β-hexosaminidase activity in RBL2H3 cells. Mouse recombinant CXCL3 protein enhanced the angiogenic potential of the culture medium of RBL2H3. CXCL3 was necessary for the enhanced angiogenic potential of the culture medium of antigen-stimulated RBL2H3. The culture medium of RBL2H3 was able to induce M2 macrophage polarization in a CXCL3-dependent manner. Recombinant CXCL3 protein also increased the expression of markers of M2 macrophage. Thus, the identification of the novel role of HDAC6-MYCN-CXCL3 axis can help better understand the pathogenesis of anaphylaxis.

Purple Sweet Potato Polysaccharide Exerting an Anti-inflammatory Effect via a TLR-Mediated Pathway by Regulating Polarization and Inhibiting the Inflammasome Activation

Purple sweet potato polysaccharide (PSPP-1) is a novel glucan; this study aimed to examine the anti-inflammatory effect of PSPP-1 and elucidate its potential mechanisms. Lipopolysaccharide (LPS)-induced RAW264.7 was used as the model of inflammation, cell viability, and levels of nitric oxide (NO), reactive oxygen species (ROS), and calcium ion (Ca2+) were analyzed. ELISA and qPCR were used to assess the productions and mRNA expression of cytokines, and Western blotting was used to assess protein expressions in the TLR-mediated pathway, macrophage polarization, and inflammasome activation. The results demonstrated PSPP-1 inhibited cell proliferation and markedly decreased NO, ROS, and Ca2+ levels. Moreover, PSPP-1 suppressed the secretions and mRNA expressions of pro-inflammatory cytokines and increased those of anti-inflammatory cytokines. Furthermore, PSPP-1 could exert anti-inflammatory effects through different pathways mediated by both TLR2 and TLR4, which modulated the expressions of essential proteins in the myeloid differentiation factor 88 (MyD88)-dependent and toll/IL-1 receptor domain-containing adaptor-inducing interferon-β (TRIF)-dependent signaling pathways. PSPP-1 even regulated the polarization of M1/M2 macrophages and inhibited the nucleotide oligomerization domain-like receptor protein 3 (NLRP3) inflammasome activation. These findings indicate that PSPP-1 can suppress LPS-induced inflammation via multiple pathways and may be a potential agent for therapeutic inflammation-related pathophysiological processes and disorders.

Effects of Jatrorrhizine on inflammatory response induced by H2O2 in microglia by regulating the MAPK/NF-κB/NLRP3 signaling pathway

Microglia-induced neuroinflammation is a contributing factor to neurodegenerative diseases. Jatrorrhizine (JAT), an alkaloid isolated from Huanglian, has been shown to have neuroprotective effects against various neurodegenerative diseases, but its impact on microglia-induced neuroinflammation remains unclear. In this study, we investigated the role of JAT in MAPK/NF-κB/NLRP3 signaling pathway in an H2O2-induced oxidative stress model using microglia (N9 cells). We divided cells into six groups, including control, JAT, H2O2, H2O2 + 5 μmol/L JAT, H2O2 + 10 μmol/L JAT, and H2O2 + 20 μmol/L minocycline groups. Cell viability was measured using MTT assay and TNF-α levels were detected with an ELISA Kit. Western blot was used to detect NLRP3, HMGB1, NF-κB, p-NF-κB, ERK, p-ERK, p38, p-p38, p-JNK, JNK, IL-1β, and IL-18 expressions. Our results showed that JAT intervention improved H2O2-induced cytotoxicity in N9 cells and reduced the elevated expression of TNF-α, IL-1β, IL-18, p-ERK/ERK, p-p38/p38, p-JNK/JNK, p-p65/p65, NLRP3, and HMGB1 in H2O2 group. Furthermore, treatment with ERK inhibitor SCH772984 specifically blocked ERK phosphorylation, resulting in decreased protein levels of p-NF-κB, NLRP3, IL-1β, and IL-18 in H2O2 group. These results suggest that the MAPK/NF-κB signaling pathway may regulate the protein levels of NLRP3. Overall, our study indicates that JAT may have a protective effect on H2O2-treated microglia via inhibition the MAPK/NF-κB/NLRP3 pathway and could be a potential therapeutic approach for neurodegenerative diseases.

HDAC6 inhibition: a significant potential regulator and therapeutic option to translate into clinical practice in renal transplantation

Histone deacetylase 6 (HDAC6), an almost exclusively cytoplasmic enzyme, plays an essential role in many biological processes and exerts its deacetylation-dependent/independent effects on a variety of target molecules, which has contributed to the flourishing growth of relatively isoform-specific enzyme inhibitors. Renal transplantation (RT) is one of the alternatively preferred treatments and the most cost-effective treatment approaches for the great majority of patients with end-stage renal disease (ESRD). HDAC6 expression and activity have recently been shown to be increased in kidney disease in a number of studies. To date, a substantial amount of validated studies has identified HDAC6 as a pivotal modulator of innate and adaptive immunity, and HDAC6 inhibitors (HDAC6i) are being developed and investigated for use in arrays of immune-related diseases, making HDAC6i a promising therapeutic candidate for the management of a variety of renal diseases. Based on accumulating evidence, HDAC6i markedly open up new avenues for therapeutic intervention to protect against oxidative stress-induced damage, tip the balance in favor of the generation of tolerance-related immune cells, and attenuate fibrosis by inhibiting multiple activations of cell profibrotic signaling pathways. Taken together, we have a point of view that targeting HDAC6 may be a novel approach for the therapeutic strategy of RT-related complications, including consequences of ischemia-reperfusion injury, induction of immune tolerance in transplantation, equilibrium of rejection, and improvement of chronic renal graft interstitial fibrosis after transplantation in patients. Herein, we will elaborate on the unique function of HDAC6, which focuses on therapeutical mechanism of action related to immunological events with a general account of the tantalizing potential to the clinic.

HDAC6 Deficiency Has Moderate Effects on Behaviors and Parkinson's Disease Pathology in Mice

Histone deacetylase 6 (HDAC6) is involved in the regulation of protein aggregation and neuroinflammation, but its role in Parkinson's disease (PD) remains controversial. In this study, Hdac6^-/- mice were generated by CRISPR-Cas9 technology for exploring the effect of HDAC6 on the pathological progression of PD. We found that male Hdac6^-/- mice exhibit hyperactivity and certain anxiety. In the acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice, though motor injury was slightly alleviated by HDAC6 deficiency, dopamine (DA) depletion in the striatum, the decrease in the number of DA neurons in the substantia nigra (SN) and the reduction in DA neuronal terminals were not affected. In addition, activation of glial cells and the expression of α-synuclein, as well as the levels of apoptosis-related proteins in the nigrostriatal pathway, were not changed in MPTP-injected wild-type and Hdac6^-/- mice. Therefore, HDAC6 deficiency leads to moderate alterations of behaviors and Parkinson's disease pathology in mice.

The Role of Histone Deacetylases in Acute Lung Injury-Friend or Foe

Acute lung injury (ALI), caused by intrapulmonary or extrapulmonary factors such as pneumonia, shock, and sepsis, eventually disrupts the alveolar-capillary barrier, resulting in diffuse pulmonary oedema and microatasis, manifested by refractory hypoxemia, and respiratory distress. Not only is ALI highly lethal, but even if a patient survives, there are also multiple sequelae. Currently, there is no better treatment than supportive care, and we urgently need to find new targets to improve ALI. Histone deacetylases (HDACs) are epigenetically important enzymes that, together with histone acetylases (HATs), regulate the acetylation levels of histones and non-histones. While HDAC inhibitors (HDACis) play a therapeutic role in cancer, inflammatory, and neurodegenerative diseases, there is also a large body of evidence suggesting the potential of HDACs as therapeutic targets in ALI. This review explores the unique mechanisms of HDACs in different cell types of ALI, including macrophages, pulmonary vascular endothelial cells (VECs), alveolar epithelial cells (AECs), and neutrophils.

Advances in the Mechanistic Study of the Control of Oxidative Stress Injury by Modulating HDAC6 Activity

Oxidative stress is defined as an injury resulting from a disturbance in the dynamic equilibrium of the redox environment due to the overproduction of active/radical oxygen exceeding the antioxidative ability of the body. This is a key step in the development of various diseases. Oxidative stress is modulated by different factors and events, including the modification of histones, which are the cores of nucleosomes. Histone modification includes acetylation and deacetylation of certain amino acid residues; this process is catalyzed by different enzymes. Histone deacetylase 6 (HDAC6) is a unique deacetylating protease that also catalyzes the deacetylation of different nonhistone substrates to regulate various physiologic processes. The intimate relationship between HDAC6 and oxidative stress has been demonstrated by different studies. The present paper aims to summarize the data obtained from a mechanistic study of HDAC6 and oxidative stress to guide further investigations on mechanistic characterization and drug development.

S-allylmercapto-N-acetylcysteine ameliorates pulmonary fibrosis in mice via Nrf2 pathway activation and NF-κB, TGF-β1/Smad2/3 pathway suppression

Pulmonary fibrosis (PF) is a chronic lung disease characterised by alveolar inflammatory injury, alveolar septal thickening, and eventually fibrosis. Patients with severe Coronavirus Disease 2019 (COVID-19) may have left a certain degree of pulmonary fibrosis. PF is commonly caused by oxidative imbalance and inflammatory damage. S-allylmercapto-N-acetylcysteine (ASSNAC) exhibits anti-oxidative and anti-inflammatory effects in other diseases. However, the pharmacodynamics of ASSNAC remain unclear for PF. This investigation aimed to evaluate the efficacy and mechanism of ASSNAC against PF. The PF model was established by TGF-β1 stimulating HFL-1 cells in vitro. ASSNAC exhibited the potential to inhibit fibroblast transformation into myofibroblasts. Also, in the PF mice model with bleomycin (BLM), the sodium salt of ASSNAC (ASSNAC-Na) inhalation was treated. ASSNAC remarkably improved mice's lung tissue structure and collagen deposition. The important indicator proteins of PF, collagen Ⅰ, collagen Ⅲ, and α-SMA significantly decreased in the ASSNAC treated groups. Besides, ASSNAC attenuated oxidative stress by reversing glutathione (GSH), superoxide dismutase (SOD) levels and interfering with Nrf2/NOX4 signaling pathways. ASSNAC showed an anti-inflammatory effect by reducing the number of inflammatory cells and inflammatory cytokines, such as TNF-α and IL-6, and blocking the NF-κB signaling pathway. ASSNAC inhibited fibroblast differentiation by blocking the TGF-β1/Smad2/3 signaling pathway. This study implicates that ASSNAC alleviates pulmonary fibrosis through fighting against oxidative stress, reducing inflammation and inhibiting fibroblast differentiation.

Highly sensitive H2O2-scavenging nano-bionic system for precise treatment of atherosclerosis

In atherosclerosis, chronic inflammatory processes in local diseased areas may lead to the accumulation of reactive oxygen species (ROS). In this study, we devised a highly sensitive H₂O₂-scavenging nano-bionic system loaded with probucol (RPP-PU), to treat atherosclerosis more effectively. The RPP material had high sensitivity to H₂O₂, and the response sensitivity could be reduced from 40 to 10 μmol/L which was close to the lowest concentration of H₂O₂ levels of the pathological environment. RPP-PU delayed the release and prolonged the duration of PU in vivo. In Apolipoprotein E deficient (ApoE^‒/‒) mice, RPP-PU effectively eliminated pathological ROS, reduced the level of lipids and related metabolic enzymes, and significantly decreased the area of vascular plaques and fibers. Our study demonstrated that the H₂O₂-scavenging nano-bionic system could scavenge the abundant ROS in the atherosclerosis lesion, thereby reducing the oxidative stress for treating atherosclerosis and thus achieve the therapeutic goals with atherosclerosis more desirably.

HDAC6-dependent deacetylation of TAK1 enhances sIL-6R release to promote macrophage M2 polarization in colon cancer

Histone deacetylase 6 (HDAC6), a member of the HDAC family, has been identified as a potential therapeutic target for tumor therapy, but the function and underlying mechanisms of HDAC6 in colon cancer are incompletely characterized. Our study showed that the infiltration ratio of M2 macrophages was increased in colon cancer tissues with high HDAC6 expression. Similarly, the knockdown of HDAC6 in colon cancer cells inhibited cocultured macrophage M2 polarization in vitro. Analysis of the antibody chip revealed that HDAC6 promoted sIL-6R release to enhance macrophage M2 polarization. Mass spectrometry and immunoprecipitation demonstrated that, mechanistically, HDAC6 interacted with transforming growth factor β-activated kinase 1 (TAK1), deacetylated TAK1 at T178 and promoted TAK1 phosphorylation. TAK1-p38 MAPK signaling could further increase the phosphorylation and activity of ADAM17, which is responsible for shedding of IL-6R. Notably, the expression of phosphorylated TAK1 was positively correlated with HDAC6 expression and macrophage M2 polarization in human colon cancer tissues. Our study revealed a new HDAC6-TAK1-ADAM17 regulatory axis that mediates sIL-6R release and macrophage polarization in colon cancer.

Microbe-Derived Antioxidants Reduce Lipopolysaccharide-Induced Inflammatory Responses by Activating the Nrf2 Pathway to Inhibit the ROS/NLRP3/IL-1β Signaling Pathway

Inflammation plays an important role in the innate immune response, yet overproduction of inflammation can lead to a variety of chronic diseases associated with the innate immune system; therefore, modulation of the excessive inflammatory response has been considered a major strategy in the treatment of inflammatory diseases. Activation of the ROS/NLRP3/IL-1β signaling axis has been suggested to be a key initiating phase of inflammation. Our previous study found that microbe-derived antioxidants (MA) are shown to have excellent antioxidant and anti-inflammatory properties; however, the mechanism of action of MA remains unclear. The current study aims to investigate whether MA could protect cells from LPS-induced oxidative stress and inflammatory responses by modulating the Nrf2-ROS-NLRP3-IL-1β signaling pathway. In this study, we find that MA treatment significantly alleviates LPS-induced oxidative stress and inflammatory responses in RAW264.7 cells. MA significantly reduce the accumulation of ROS in RAW264.7 cells, down-regulate the levels of pro-inflammatory factors (TNF-α and IL-6), inhibit NLRP3, ASC, caspase-1 mRNA, and protein levels, and reduce the mRNA, protein levels, and content of inflammatory factors (IL-1β and IL-18). The protective effect of MA is significantly reduced after the siRNA knockdown of the NLRP3 gene, presumably related to the ability of MA to inhibit the ROS-NLRP3-IL-1β signaling pathway. MA is able to reduce the accumulation of ROS and alleviate oxidative stress by increasing the content of antioxidant enzymes, such as SOD, GSH-Px, and CAT. The protective effect of MA may be due to its ability of MA to induce Nrf2 to enter the nucleus and initiate the expression of antioxidant enzymes. The antioxidant properties of MA are further enhanced in the presence of the Nrf2 activator SFN. After the siRNA knockdown of the Nrf2 gene, the antioxidant and anti-inflammatory properties of MA are significantly affected. These findings suggest that MA may inhibit the LPS-stimulated ROS/NLRP3/IL-1β signaling axis by activating Nrf2-antioxidant signaling in RAW264.7 cells. As a result of this study, MA has been found to alleviate inflammatory responses and holds promise as a therapeutic agent for inflammation-related diseases.

NOD2-mediated HDAC6/NF-κb signalling pathway regulates ferroptosis induced by extracellular histone H3 in acute liver failure

Acute liver failure (ALF) is life-threatening and often associated with high mortality rates. The aim of the present study was to investigate whether extracellular histone H3 could induce ferroptosis in hepatic macrophages in ALF and explore its potential mechanism. RAW264.7 macrophages and C57BL/6 mice were used in this study. LPS, D-galactosamine (D-Gal), histone H3, histone H3 antibody, NOD2 agonist Muramyl Dipeptide (MDP) and HDAC6-siRNA were administered in this study. The key molecules of ferroptosis, NOD2, HDAC6 and the NF-κb pathway, were detected. In vitro, histone H3 was released into the extracellular environment from cell nucleus after LPS exposure. In addition, histone H3 could induce ferroptosis in RAW264.7 macrophages with increased level of Fe²⁺ and ROS and decreased levels of GPX4 and GSH. MDP further aggravated ferroptosis in RAW264.7 macrophages stimulated by histone H3, which was accompanied by elevated NOD2, HDAC6, p-P65 and IκBα. HDAC6-siRNA ameliorated ferroptosis in RAW264.7 macrophages induced by histone H3, which was accompanied by decreased levels of HDAC6, p-P65 and IκBα. However, HDAC6-siRNA did not alter NOD2 levels in RAW264.7 macrophages administered histone H3. In vivo, the levels of NOD2, HDAC6 the NF-κb pathway and ferroptosis were increased in ALF mice, which were downregulated by histone H3 antibody and upregulated by histone H3. Extracellular histone H3 could induce ferroptosis in hepatic macrophages in ALF by regulating theNOD2-mediated HDAC6/NF-κb signalling pathway.

Glucogallin Attenuates the LPS-Induced Signaling in Macrophages and Protects Mice against Sepsis

The anti-oxidant and anti-inflammatory effect of beta-glucogallin (BGG), a plant-derived natural product, was evaluated in both in vitro and in vivo studies. For the in vitro study, the ability of BGG pre-treatment to quench LPS-induced effects compared to LPS alone in macrophages was investigated. It was found that BGG pre-treatment showed a significant decrease in ROS, NO, superoxide, and pro-inflammatory cytokines (TNF-alpha, IL-4, IL-17, IL-1β, and IL-6) and increased reduced glutathione coupled with the restoration of mitochondrial membrane potential. Gene profiling and further validation by qPCR showed that BGG pre-treatment downregulated the LPS-induced expression of c-Fos, Fas, MMP-9, iNOS, COX-2, MyD88, TRIF, TRAF6, TRAM, c-JUN, and NF-κB. We observed that BGG pre-treatment reduced nuclear translocation of LPS-activated NF-κB and thus reduced the subsequent expressions of NLRP3 and IL-1β, indicating the ability of BGG to inhibit inflammasome formation. Molecular docking studies showed that BGG could bind at the active site of TLR4. Finally, in the LPS-driven sepsis mouse model, we showed that pre-treatment with BGG sustained toxic shock, as evident from their 100% survival. Our study clearly showed the therapeutic potential of BGG in toxic shock syndrome.

Macrophage Polarization and Reprogramming in Acute Inflammation: A Redox Perspective

Macrophage polarization refers to the process by which macrophages can produce two distinct functional phenotypes: M1 or M2. The balance between both strongly affects the progression of inflammatory disorders. Here, we review how redox signals regulate macrophage polarization and reprogramming during acute inflammation. In M1, macrophages augment NADPH oxidase isoform 2 (NOX2), inducible nitric oxide synthase (iNOS), synaptotagmin-binding cytoplasmic RNA interacting protein (SYNCRIP), and tumor necrosis factor receptor-associated factor 6 increase oxygen and nitrogen reactive species, which triggers inflammatory response, phagocytosis, and cytotoxicity. In M2, macrophages down-regulate NOX2, iNOS, SYNCRIP, and/or up-regulate arginase and superoxide dismutase type 1, counteract oxidative and nitrosative stress, and favor anti-inflammatory and tissue repair responses. M1 and M2 macrophages exhibit different metabolic profiles, which are tightly regulated by redox mechanisms. Oxidative and nitrosative stress sustain the M1 phenotype by activating glycolysis and lipid biosynthesis, but by inhibiting tricarboxylic acid cycle and oxidative phosphorylation. This metabolic profile is reversed in M2 macrophages because of changes in the redox state. Therefore, new therapies based on redox mechanisms have emerged to treat acute inflammation with positive results, which highlights the relevance of redox signaling as a master regulator of macrophage reprogramming.

Role of Selective Histone Deacetylase 6 Inhibitor ACY-1215 in Cancer and Other Human Diseases

The deacetylation process regulated by histone deacetylases (HDACs) plays an important role in human health and diseases. HDAC6 belongs to the Class IIb of HDACs family, which mainly modifies non-histone proteins located in the cytoplasm. HDAC6 plays a key role in tumors, neurological diseases, and inflammatory diseases. Therefore, targeting HDAC6 has become a promising treatment strategy in recent years. ACY-1215 is the first orally available highly selective HDAC6 inhibitor, and its efficacy and therapeutic effects are being continuously verified. This review summarizes the research progress of ACY-1215 in cancer and other human diseases, as well as the underlying mechanism, in order to guide the future clinical trials of ACY-1215 and more in-depth mechanism researches.

Oridonin attenuates LPS-induced early pulmonary fibrosis by regulating impaired autophagy, oxidative stress, inflammation and EMT

CONTEXT

Oridonin (Ori) possesses anti-inflammatory, antioxidant and antitumor properties. However, the effects of Ori on Lipopolysaccharide (LPS)-induced early pulmonary fibrosis remain unclear.

OBJECTIVE

We evaluated the protective effects of Ori on the mice model of pulmonary fibrosis.

MATERIALS AND METHODS

The BALB/C mice were given LPS (1 mg/kg) or Ori (20 mg/kg) according to experimental grouping. Then the left lung tissues were used for HE, immunohistochemical and Masson staining, and the right lung tissues were used for hydroxyproline measurement and western blot experiments. Bronchoalveolar lavage fluid was collected for Giemsa staining.

RESULTS

The high levels of hydroxyproline induced by LPS were reduced by Ori treatment. Immunohistochemical staining and western blot analysis showed that Ori inhibited the increased levels of fibrosis-related proteins (α-smooth muscle actin, transforming growth factor-β, Collagen Ⅰ and phosphorylated-smad). Additionally, Ori treatment increased E-cadherin levels and decreased in Snail and Slug levels. Besides, Ori could suppress LPS-induced the infiltration of neutrophils and activation of the NLRP3 inflammasome. In addition, LPS caused the upregulation of NADPH oxidase 4 and exacerbated lung fibrosis. As the activator of NF-E2 related factor-2, Ori exerted protective effects in this animal model. Moreover, Ori reversed the LPS-triggered increases in Beclin-1, P62/sequestosome 1, autophagy related 3 and LC3.

CONCLUSIONS

These findings suggested that Ori protected against LPS-induced early pulmonary fibrosis by inhibiting NLRP3-dependent inflammation, NADPH oxidase 4-dependent oxidative stress, the impaired autophagy and epithelial mesenchymal transformation.

Sp1 S-Sulfhydration Induced by Hydrogen Sulfide Inhibits Inflammation via HDAC6/MyD88/NF-κB Signaling Pathway in Adjuvant-Induced Arthritis

Histone deacetylase 6 (HDAC6) acts as a regulator of the nuclear factor kappa-B (NF-κB) signaling pathway by deacetylating the non-histone protein myeloid differentiation primary response 88 (MyD88) at lysine residues, which is an adapter protein for the Toll-like receptor (TLR) and interleukin (IL)-1β receptor. Over-activated immune responses, induced by infiltrated immune cells, excessively trigger the NF-κB signaling pathway in other effector cells and contribute to the development of rheumatoid arthritis (RA). It has also been reported that HDAC6 can promote the activation of the NF-κB signaling pathway. In the present study, we showed that HDAC6 protein level was increased in the synovium tissues of adjuvant-induced arthritis rats. In addition, hydrogen sulfide (H₂S) donor S-propargyl-cysteine (SPRC) can inhibit HDAC6 expression and alleviate inflammatory response in vivo. In vitro study revealed that HDAC6 overexpression activated the NF-κB signaling pathway by deacetylating MyD88. Meanwhile, sodium hydrosulfide (NaHS) or HDAC6 inhibitor tubastatin A (tubA) suppressed the pro-inflammatory function of HDAC6. Furthermore, the reduced expression of HDAC6 appeared to result from transcriptional inhibition by S-sulfhydrating specificity protein 1 (Sp1), which is a transcription factor of HDAC6. Our results demonstrate that Sp1 can regulate HDAC6 expression, and S-sulfhydration of Sp1 by antioxidant molecular H₂S ameliorates RA progression via the HDAC6/MyD88/NF-κB signaling pathway.

Regulatory Mechanism of MicroRNA-9 / Long Non-Coding RNA XIST Expression on Mouse Macrophage RAW264.7 Apoptosis Induced by Oxidized Low Density Lipoprotein

It aims to analyze the influential mechanism of microRNA-9 (miR-9) and long non-coding RNA XIST (lncRNA XIST) expression on the proliferation and apoptosis of macrophages induced by oxidized-low density lipoprotein (ox-LDL). Firstly, lncRNA XIST overexpression vector was constructed, and then RAW264.7 cells were used as the research object. Methylthiazolyl tetrazolium (MTT) method, flow cytometry, and Western blot were used to detect and compare the differences of cell proliferation, apoptosis, and the expression levels of apoptosis signal-regulating kinase 1 (ASK1), c-Jun N-terminal kinase (JNK), matrix metalloproteinase-9 (MMP-9), and B-cell lymphoma-2 (Bcl-2) after ox-LDL induction and transfection of miR-9 mimic, miR-9 inhibitor and XIST expression vector, respectively. The results showed that lncRNA XIST overexpression vector was successfully constructed and transfected into cells, wh5ich can inhibit the expression level of miR-9. Compared with the normal control group, ox-LDL can inhibit cell proliferation, promote cell apoptosis, and increase the expression level of target protein. Moreover, transfection of XIST expression vector based on ox-LDL induction can significantly enhance the inhibition of cell proliferation, and promote cell apoptosis and the expression of target protein. Transfection of miR-9 mimic can improve the biological changes induced by ox-LDL. After co-transfection of miR-9 mimic and XIST expression vector based on ox-LDL induction, cell proliferation, apoptosis, and target protein expression level were not significantly different from those induced by ox-LDL alone. In summary, the increased expression level of miR-9 can inhibit the apoptosis of macrophages induced by ox-LDL. lncRNA XIST can positively regulate the apoptosis of macrophages induced by ox-LDL.

HDAC6 inhibitor ACY-1215 improves neuropathic pain and its comorbidities in rats of peripheral nerve injury by regulating neuroinflammation

The fact that neuropathic pain (NP) has no effective therapy and is frequently accompanied by psychiatric comorbidities is well established. Aberrant neuroinflammation plays an important role in the development and maintenance of NP. HDAC6 inhibitors have been demonstrated to ameliorate mechanical allodynia brought on by chemotherapy and peripheral nerve damage. However, its pharmacological mechanisms and its effects on NP-related mental disorders have not been fully elucidated. The present study was dedicated to exploring the effects of ACY-1215 (a specific HDAC6 inhibitor) on neuroinflammation and behavioral abnormalities associated with NP. In this work, spinal nerve ligation (SNL) was performed as an NP model on rats. Mechanical allodynia, cognitive impairment, and depressive-like behavior caused by SNL were attenuated by continuous intraperitoneal injection of ACY-1215. Moreover, ACY-1215 administration suppressed SNL-induced neuroinflammatory responses (including microgliosis, the elevation of pro-inflammatory factors IL-1β and TNF-α) in ligation of the ipsilateral spinal dorsal horn (iSDH), hippocampus (HPC) and prefrontal cortex (PFC). Mechanistically, MyD88-dependent pro-inflammatory pathways (MyD88/NF-κB and MyD88/ERK) were activated in the iSDH following SNL and were inhibited by ACY-1215. Moreover, ACY-1215 enhanced the acetylation modification of MyD88 and inhibited the SNL-induced elevation of MyD88 without affecting its transcription in the iSDH. These findings suggest that pharmacological inhibition of HDAC6 can ameliorate NP and its psychiatric complications through modulating neuroinflammation, in part by blocking the MyD88-mediated pro-inflammatory pathways. The possible mechanism is that ACY-1215 prevents the elevation of MyD88 reactivity by increasing its acetylation level. Notably, neither SNL nor ACY-1215 significantly altered MyD88 expression in HPC and PFC, indicating differentiated pro-inflammatory mechanisms in the supraspinal neural regions.

Methyl p‑hydroxycinnamate exerts anti‑inflammatory effects in mouse models of lipopolysaccharide‑induced ARDS

Methyl p-hydroxycinnamate (MH), an esterified derivative of p-Coumaric acid exerts anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Based on these effects, the present study investigated the protective role of MH in a mouse model of LPS-induced acute respiratory distress syndrome (ARDS). The results demonstrated that administration of LPS (5 mg/kg intranasally) markedly increased the neutrophil/macrophage numbers and levels of inflammatory molecules (TNF-α, IL-6, IL-1β and reactive oxygen species) in the bronchoalveolar lavage fluid (BALF) of mice. On histological examination, the presence of inflammatory cells was observed in the lungs of mice administered LPS. LPS also notably upregulated the secretion of monocyte chemoattractant protein-1 and protein content in BALF as well as expression of inducible nitric oxide synthase in the lungs of mice; it also caused activation of p38 mitogen-activated protein kinase (MAPK) and NF-κB signaling. However, MH treatment significantly suppressed LPS-induced upregulation of inflammatory cell recruitment, inflammatory molecule levels and p38MAPK/NF-κB activation, and also led to upregulation of heme oxygenase-1 (HO-1) expression in the lungs of mice. In addition, the ability of MH to induce HO-1 expression was confirmed in RAW264.7 macrophages. Taken together, the findings of the present study indicated that MH may exert protective effects against airway inflammation in ARDS mice by inhibiting inflammatory cell recruitment and the production of inflammatory molecules.

LncRNA KCNQ1OT1 (potassium voltage-gated channel subfamily Q member 1 opposite strand/antisense transcript 1) aggravates acute kidney injury by activating p38/NF-κB pathway via miR-212-3p/MAPK1 (mitogen-activated protein kinase 1) axis in sepsis

Acute kidney injury (AKI), a common complication of sepsis, is characterized by a rapid loss of renal excretory function. A variety of etiologies and pathophysiological processes may contribute to AKI. Previously, mitogen-activated protein kinase 1 (MAPK1) was reported to regulate cellular processes in various sepsis-associated diseases. The current study aimed to further explore the biological function and regulatory mechanism of MAPK1 in sepsis-induced AKI. In our study, MAPK1 exhibited high expression in the serum of AKI patients. Functionally, knockdown of MAPK1 suppressed inflammatory response, cell apoptosis in response of lipopolysaccharide (LPS) induction in HK-2 cells. Moreover, MAPK1 deficiency alleviated renal inflammation, renal dysfunction, and renal injury in vivo. Mechanistically, MAPK1 could activate the downstream p38/NF-κB pathway. Moreover, long noncoding RNA potassium voltage-gated channel subfamily Q member 1 opposite strand/antisense transcript 1 (KCNQ1OT1) was identified to serve as a competing endogenous RNA for miR-212-3p to regulate MAPK1. Finally, rescue assays indicated that the inhibitory effect of KCNQ1OT1 knockdown on inflammatory response, cell apoptosis, and p38/NF-κB pathway was reversed by MAPK1 overexpression in HK-2 cells. In conclusion, KCNQ1OT1 aggravates acute kidney injury by activating p38/NF-κB pathway via miR-212-3p/MAPK1 axis in sepsis. Therefore, KCNQ1OT may serve as a potential biomarker for the prognosis and diagnosis of AKI patients.

HDAC6 and CXCL13 Mediate Atopic Dermatitis by Regulating Cellular Interactions and Expression Levels of miR-9 and SIRT1

Histone deacetylase 6 (HDAC6) has been known to regulate inflammatory diseases. The role of HDAC6 in allergic skin inflammation has not been studied. We studied the role of HDAC6 in atopic dermatitis (AD) and the mechanisms associated with it. The decreased expression or chemical inhibition of HDAC6 suppressed AD by decreasing autophagic flux and cellular features of AD. AD increased expression levels of the Th1 and Th2 cytokines, but decreased expression levels of forkhead box P3 (FoxP3) and interleukin-10 (IL-10) in an HDAC6-dependent manner. CXC chemokine ligand 13 (CXCL13), which was increased in an HDAC6-depenednt manner, mediated AD. MiR-9, negatively regulated by HDAC6, suppressed AD by directly regulating the expression of sirtuin 1 (SIRT1). The downregulation or inhibition of SIRT1 suppressed AD. Experiments employing culture medium and transwell suggested that cellular interactions involving mast cells, keratinocytes, and dermal fibroblast cells could promote AD; HDAC6 and CXCL13 were found to be necessary for these cellular interactions. Mouse recombinant CXCL13 protein increased HDAC6 expression in skin mast cells and dermal fibroblast cells. CXCL13 protein was found to be present in the exosomes of DNCB-treated skin mast cells. Exosomes of DNCB-treated skin mast cells enhanced invasion potentials of keratinocytes and dermal fibroblast cells and increased expression levels of HDAC6, SIRT1 and CXCL13 in keratinocytes and dermal fibroblast cells. These results indicate that HDAC6 and CXCL13 may serve as targets for the developing anti-atopic drugs.

Classical HDACs in the regulation of neuroinflammation

Neuroinflammation is a key factor of the pathology of various neurological diseases (brain injury, depression, neurodegenerative diseases). It is a complex and orderly process that relies on various types of glial cells and peripheral immune cells. Inhibition of neuroinflammation can reduce the severity of neurological diseases. The initiation, progression, and termination of inflammation require gene activation, epigenetic modification, transcriptional translation, and post-translational regulation, all of which are tightly regulated by different enzymes. Epigenetics refers to the regulation of epigenetic gene expression by epigenetic changes (DNA methylation, histone modification, and non-coding RNAs such as miRNA) that are not dependent on changes in gene sequence and are heritable. Histone deacetylases (HDACs) are a group of important enzymes that regulate epigenetics. They can remove the acetyl group on the lysine ϵ-amino group of the target protein, thereby affecting gene transcription or altering protein activity. HDACs are involved in the regulation of immunity and inflammation. HDAC inhibitor (HDACi) has also become a new hotspot in the research of anti-inflammatory drugs. Therefore, the aim of the current review is to discuss and summarize the role and mechanism of different HDACs in neuroinflammation and the corresponding role of HDACi in neurological diseases, and to providing new ideas for future research on neuroinflammation-related diseases and drug development.

EGR3-HDAC6-IL-27 Axis Mediates Allergic Inflammation and Is Necessary for Tumorigenic Potential of Cancer Cells Enhanced by Allergic Inflammation-Promoted Cellular Interactions

The objective of this study was to investigate mechanisms of allergic inflammation both in vitro and in vivo in details. For this, RNA sequencing was performed. Early growth response 3 gene (Egr3) was one of the most highly upregulated genes in rat basophilic leukemia (RBL2H3) cells stimulated by antigen. The role of Egr3 in allergic inflammation has not been studied extensively. Egr3 was necessary for passive cutaneous anaphylaxis (PCA) and passive systemic anaphylaxis (PSA). Egr3 promoter sequences contained potential binding site for NF-κB p65. NF-κB p65 directly regulated Egr3 expression and mediated allergic inflammation in vitro. Histone deacetylases (HDACs) is known to be involved in allergic airway inflammation. HDAC6 promoter sequences contained potential binding site for EGR3. EGR3 showed binding to promoter sequences of HDAC6. EGR3 was necessary for increased expression of histone deacetylase 6 (HDAC6) in antigen-stimulated RBL2H3 cells. HDAC6 mediated allergic inflammation in vitro and PSA. TargetScan analysis predicted that miR-182-5p was a negative regulator of EGR3. Luciferase activity assay confirmed that miR-182-5p was a direct regulator of EGR3. MiR-182-5p mimic inhibited allergic inflammation both in vitro and in vivo. Cytokine array showed that HDAC6 was necessary for increased interleukin-27 (IL-27) expression in BALB/C mouse model of PSA. Antigen stimulation did not affect expression of EBI3, another subunit of IL-27 in RBL2H3 cells or BALB/C mouse model of PCA or PSA. IL-27 receptor alpha was shown to be able to bind to HDAC6. IL-27 p28 mediated allergic inflammation in vitro, PCA, and PSA. Mouse recombinant IL-27 protein promoted features of allergic inflammation in an antigen-independent manner. HDAC6 was necessary for tumorigenic and metastatic potential enhanced by PSA. PSA enhanced the metastatic potential of mouse melanoma B16F1 cells in an IL-27-dependent manner. Experiments employing culture medium and mouse recombinant IL-27 protein showed that IL-27 mediated and promoted cellular interactions involving B16F1 cells, lung macrophages, and mast cells during allergic inflammation. IL-27 was present in exosomes of antigen-stimulated RBL2H3 cells. Exosomes from antigen-stimulated RBL2H3 cells enhanced invasion of B16F1 melanoma cells in an IL-27-dependemt manner. These results present evidence that EGR3-HDAC6-IL-27 axis can regulate allergic inflammation by mediating cellular interactions.

Inhibition of miR-128-3p Attenuated Doxorubicin-Triggered Acute Cardiac Injury in Mice by the Regulation of PPAR-γ

Background

The clinical usefulness of doxorubicin (DOX), an anthracycline with antitumor activity, is limited by its cardiotoxicity. Oxidative stress and myocardial apoptosis were closely associated with DOX-induced cardiac dysfunction. It has been reported that microRNA-128-3p (miR-128-3p) was involved into the regulation of redox balance. However, the role of miR-128-3p in DOX-related cardiac injury remains not yet understood. The aim of this study was to investigate the biological effect of miR-128-3p in DOX-induced cardiotoxicity.

Methods

To induce DOX-related acute cardiac injury, mice were subjected to a single injection of DOX. Inhibition of myocardial miR-128-3p was achieved by an adeno-associated virus (AAV9) system carrying a miR-128-3p sponge.

Results

The data in our study indicated that miR-128-3p was upregulated in DOX-treated hearts and cardiomyocytes. Inhibition of miR-128-3p attenuated DOX-related cardiac injury and improved cardiac function in mice. Moreover, miR-128-3p inhibition could suppress myocardial inflammatory response, oxidative damage, and cell apoptotic death in DOX-treated mice. Further analysis showed that miR-128-3p could directly target peroxisome proliferator-activated receptor γ (PPAR-γ) and decrease PPAR-γ expression. Moreover, the protective effects provided by miR-128-3p inhibition were abolished by a PPAR-γ antagonist in vivo and in vitro.

Conclusions

miR-128-3p inhibition attenuated DOX-related acute cardiac injury via the regulation of PPAR-γ in mice.

Histone Deacetylase 6 Regulates the Activation of M1 Macrophages by the Glycolytic Pathway During Acute Liver Failure

Background

The glycolysis pathway of M1 macrophages is a key factor affecting the inflammatory response. The aim of this article is to investigate the role of histone deacetylase 6 (HDAC6) in the M1 macrophage glycolysis pathway during acute liver failure (ALF).

Methodology

Targeted metabolomics for quantitative analysis of energy metabolites technology was used to detect the characteristics of energy metabolism for 8 ALF patients and 8 normal volunteers. The ALF mice model was intervened with HDAC6 inhibitor ACY-1215. iTRAQ/TMT quantitative proteomics was used to detect protein expression in livers in different mice groups. The liver function, energy metabolites, M1 macrophages, cytokines, and pathological structure, DDX3X, NLRP3 and DNMT1 in liver tissue were detected. The changes of the above molecules were verified in cell groups.

Results

ALF patients and mice have significant energy metabolism disorders, accompanied by activation of M1 macrophages. After the intervention of ACY-1215, the activated M1 macrophages and cytokines levels in the mouse liver were reduced. The levels of IDH1, MDH1, and ATP were significantly increased. The expression of DDX3X increased, while the expression of NLRP3 and DNMT1 decreased. ACY-1215 could reduce the model cell apoptosis level and inflammatory response, and improve energy metabolism. It could also promote the expression of DDX3X, and inhibit the expression of NLRP3 and DNMT1.

Conclusion

ACY-1215 could inhibit the activation of M1 macrophages by improving the glycolytic pathway through regulating DNMT1 and DDX3X/NLRP3 signals to alleviate ALF.

Zi Qi Decoction Alleviates Liver Fibrosis by Inhibiting the Toll-Like Receptor 4 (TLR4)-Related Nuclear Factor kappa b (NF-κB) and Mitogen-Activated Protein Kinase (MAPK) Signaling Pathways

Background

Hepatic stellate cells (HSCs) play a vital role in hepatic fibrogenesis. Our recent clinical study indicated that the Zi Qi decoction, a Traditional Chinese Medicine formula, exhibited good efficacy in alleviating liver fibrosis, but the underlying mechanism remains elusive.

Material/Methods

Rats repeatedly injected with CCl₄ and cells stimulated with lipopolysaccharide were used as in vivo and in vitro models for liver fibrosis, respectively. The viability of LX-2 cells was evaluated with MTT assay. Relative messenger RNA (mRNA) expression of representative extracellular matrix (ECM) components was detected with real-time quantitative polymerase chain reaction (RT-qPCR). Moreover, total and phosphorylation levels of ECM proteins and pathway-related proteins were detected with western blotting. Immunofluorescent staining was used to show the nuclear translocation of nuclear factor kappa b (NF-κB) p65. Hematoxylin & eosin (H&E) and Masson trichrome staining and immunohistochemistry were performed to evaluate the extent of liver fibrosis. The levels of alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transpeptidase (GGT), Hyp, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were tested with an enzyme-linked immunosorbent assay. In addition, 7.0T micro-magnetic resonance imaging (micro-MRI) was used to evaluate the severity of hepatic damage.

Results

The Zi Qi decoction inhibited lipopolysaccharide-mediated upregulation of mRNA and protein levels of representative ECM proteins both in vivo and in vitro. The Zi Qi decoction also suppressed activation of the Toll-like receptor 4 (TLR4)-related NF-κB signaling pathway and subsequently inhibited the nuclear translocation of activated NF-κB. Moreover, another TLR4 downstream pathway, mitogen-activated protein kinase (MAPK), was simultaneously restrained. The results of liver pathology and MRI in rat models also suggested the efficacy of the Zi Qi decoction in attenuating liver damage.

Conclusions

The Zi Qi decoction inhibited liver fibrosis by inhibiting the TLR4-related NF-κB and MAPK signaling pathways and preventing activation of HSCs.

Infection with a newly designed dual fluorescent reporter HIV-1 effectively identifies latently infected CD4+ T cells

The major barrier to curing HIV-1 infection is a small pool of latently infected cells that harbor replication-competent viruses, which are widely considered the origin of viral rebound when antiretroviral therapy (ART) is interrupted. The difficulty in distinguishing latently infected cells from the vast majority of uninfected cells has represented a significant bottleneck precluding comprehensive understandings of HIV-1 latency. Here we reported and validated a newly designed dual fluorescent reporter virus, DFV-B, infection with which primary CD4⁺ T cells can directly label latently infected cells and generate a latency model that was highly physiological relevant. Applying DFV-B infection in Jurkat T cells, we generated a stable cell line model of HIV-1 latency with diverse viral integration sites. High-throughput compound screening with this model identified ACY-1215 as a potent latency reversing agent, which could be verified in other cell models and in primary CD4⁺ T cells from ART-suppressed individuals ex vivo. In summary, we have generated a meaningful and feasible model to directly study latently infected cells, which could open up new avenues to explore the critical events of HIV-1 latency and become a valuable tool for the research of AIDS functional cure.

The second phase of brain trauma can be controlled by nutraceuticals that suppress DAMP-mediated microglial activation

INTRODUCTION

A delayed second wave of brain trauma is mediated in large part by microglia that are activated to a pro-inflammatory M1 phenotype by DAMP proteins released by dying neurons. These microglia can promote apoptosis or necrosis in neighboring neurons by producing a range of pro-inflammatory cytokines and the deadly oxidant peroxynitrite. This second wave could therefore be mitigated with agents that blunt the post-traumatic M1 activation of microglia and that preferentially promote a pro-healing M2 phenotype.

AREAS COVERED

The literature on nutraceuticals that might have clinical potential in this regard.

EXPERT OPINION

The chief signaling pathway whereby DAMPs promote M1 microglial activation involves activation of toll-like receptor 4 (TLR4), NADPH oxidase, NF-kappaB, and the stress activated kinases JNK and p38. The green tea catechin EGCG can suppress TLR4 expression. Phycocyanobilin can inhibit NOX2-dependent NADPH oxidase, ferulate and melatonin can oppose pro-inflammatory signal modulation by NADPH oxidase-derived oxidants. Long-chain omega-3 fatty acids, the soy isoflavone genistein, the AMPK activator berberine, glucosamine, and ketone bodies can down-regulate NF-kappaB activation. Vitamin D activity can oppose JNK/p38 activation. A sophisticated program of nutraceutical supplementation may have important potential for mitigating the second phase of neuronal death and aiding subsequent healing.

Tribulus terrestris L. Extract Protects against Lipopolysaccharide-Induced Inflammation in RAW 264.7 Macrophage and Zebrafish via Inhibition of Akt/MAPKs and NF-κB/iNOS-NO Signaling Pathways

Inflammation response is a regulated cellular process and excessive inflammation has been recognized in numerous diseases, such as cardiovascular disease, neurodegenerative disease, inflammatory bowel disease, and cancer. Tribulus terrestris L. (TT), also known as Bai Jili in Chinese, has been applied in traditional Chinese medicine for thousands of years while its anti-inflammatory activity and underlying mechanism are not fully elucidated. Here, we hypothesize Tribulus terrestris L. extract (BJL) which presents anti-inflammatory effect, and the action mechanism was also investigated. We employed the transgenic zebrafish line Tg(MPO:GFP), which expresses green fluorescence protein (GFP) in neutrophils, and mice macrophage RAW 264.7 cells as the in vivo and in vitro model to evaluate the anti-inflammatory effect of BJL, respectively. The production of nitric oxide (NO) was measured by Griess reagent. The mRNA expression levels of inflammatory cytokines and inducible nitric oxide synthase (iNOS) were measured by real-time PCR, and the intracellular total or phosphorylated protein levels of NF-κB, Akt, and MAPKs including MEK, ERK, p38, and JNK were detected by western blot. We found that BJL significantly inhibited fin transection or lipopolysaccharide- (LPS-) induced neutrophil migration and aggregation in zebrafish in vivo. In mice macrophage RAW 264.7 cells, BJL ameliorated LPS-triggered excessive release of NO and transcription of inflammatory cytokine genes including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β). BJL also reduced the LPS-induced elevations of intracellular iNOS and nuclear factor kappa B (NF-κB) which mediate the cellular NO and inflammatory cytokine productions, respectively. Moreover, LPS dramatically increased the phosphorylation of Akt and MAPKs including MEK, ERK, p38, and JNK in RAW 264.7 cells, while cotreatment BJL with LPS suppressed their phosphorylation. Taken together, our data suggested that BJL presented potent anti-inflammatory effect and the underlying mechanism was closely related to the inhibition of Akt/MAPKs and NF-κB/iNOS-NO signaling pathways.

Role of HDAC6 inhibition in sepsis-induced acute respiratory distress syndrome (Review)

Acute respiratory distress syndrome (ARDS) induced by sepsis contributes remarkably to the high mortality rate observed in intensive care units, largely due to a lack of effective drug therapies. Histone deacetylase 6 (HDAC6) is a class-IIb deacetylase that modulates non-nuclear protein functions via deacetylation and ubiquitination. Importantly, HDAC6 has been shown to exert anti-cancer, anti-neurodegeneration, and immunological effects, and several HDAC6 inhibitors have now entered clinical trials. It has also been recently shown to modulate inflammation, and HDAC6 inhibition has been demonstrated to markedly suppress experimental sepsis. The present review summarizes the role of HDAC6 in sepsis-induced inflammation and endothelial barrier dysfunction in recent years. It is proposed that HDAC6 inhibition predominantly ameliorates sepsis-induced ARDS by directly attenuating inflammation, which modulates the innate and adaptive immunity, transcription of pro-inflammatory genes, and protects endothelial barrier function. HDAC6 inhibition protects against sepsis-induced ARDS, thereby making HDAC6 a promising therapeutic target. However, HDAC inhibition may be associated with adverse effects on the embryo sac and oocyte, necessitating further studies.

Increased transcription of TSPO, HDAC2, and HDAC6 in the amygdala of males with alcohol use disorder

INTRODUCTION

Repeated exposure to high doses of alcohol triggers neuroinflammatory processes that contribute to craving and mood dysfunction in alcohol use disorder (AUD). The upregulation of the translocator protein (TSPO) is considered a biomarker of neuroinflammation, and TSPO ligands have been used as neuroimaging biomarkers of neuroinflammation. Epigenetic mechanisms are also implicated in neuroinflammatory responses to alcohol, and elevated expression of HDAC2 and HDAC6 has been reported in the brain of animals exposed to chronic alcohol.

METHODS

The present study examined the transcriptional regulation of TSPO, HDAC2, and HDAC6 in human postmortem brain tissue from males previously diagnosed with AUD (n = 11) compared to age-matched nondependent males (n = 13) in four brain regions relevant to AUD: prefrontal cortex (PFC), nucleus accumbens (NAc), hippocampus (HPP), and amygdala (AMY).

RESULTS

Translocator protein mRNA levels in AMY and PFC and HDAC2 and HDAC6 mRNA levels in AMY were upregulated in AUD compared to controls. In AMY, TSPO mRNA levels were positively associated with HDAC2 and HDAC6 mRNA levels, suggesting a possible regulation of TSPO by HDAC2 and HDAC6 in this brain region. In contrast, there were no group differences for TSPO, HDAC2, and HDAC6 in NAc and HPP.

CONCLUSION

Our study is the first to find upregulated TSPO mRNA levels in AMY and PFC in postmortem brains from AUD consistent with neuroinflammation, and in the amygdala, they implicate epigenetic regulation of TSPO by HDAC2 and HDAC6.

Thal protects against paraquat-induced lung injury through a microRNA-141/HDAC6/IκBα-NF-κB axis in rat and cell models

The protective functions of thalidomide in paraquat (PQ)-induced injury have been reported. But the mechanisms remain largely unknown. In this research, a PQ-treated rat model was established and further treated with thalidomide. Oedema and pathological changes, oxidative stress, inflammation, fibrosis and cell apoptosis in rat lungs were detected. A PQ-treated RLE-6TN cell model was constructed, and the viability and apoptosis rate of cells were measured. Differentially expressed microRNAs (miRNAs) after thalidomide administration were screened out. Binding relationship between miR-141 and histone deacetylase 6 (HDAC6) was validated. Altered expression of miR-141 and HDAC6 was introduced to identify their involvements in thalidomide-mediated events. Consequently, thalidomide administration alone exerted no damage to rat lungs; in addition it reduced PQ-induced oedema. The oxidative stress, inflammation and cell apoptosis in rat lungs were reduced by thalidomide. In RLE-6TN cells, thalidomide increased cell viability and decreased apoptosis. miR-141 was responsible for thalidomide-mediated protective events by targeting HDAC6. Overexpression of HDAC6 blocked the protection of thalidomide against PQ-induced injury via activating the IkBα-NF-κB signalling pathway. Collectively, this study evidenced that thalidomide protects lung tissues from PQ-induced injury through a miR-141/HDAC6/IkBα-NF-κB axis.

DOCK2 contributes to endotoxemia-induced acute lung injury in mice by activating proinflammatory macrophages

Dedicator of cytokinesis 2 (DOCK2), an atypical Rac activator, has important anti-inflammatory properties in blepharitis, enteric bacterial infection and colitis. However, the roles of DOCK2 in macrophage activation and acute lung injury (ALI) are still poorly elucidated. In vitro studies demonstrated that DOCK2 was essential for the nucleotide-sensing Toll-like receptor (TLR) 4-mediated inflammatory response in macrophages. We also confirmed that exposure of macrophages to LPS induced Rac activation through a TLR4-independent, DOCK2-dependent mechanism. Phosphorylation of IκB kinase (IKK) β and nuclear translocation of transcription factor nuclear factor kappa B (NF-κB) were impaired in Ad-shDOCK2-expressing macrophages, resulting in a decreased inflammatory response. Similar results were obtained when EHop-016 (a Rac inhibitor) was used to treat uninfected macrophages. In summary, these data indicate that the DOCK2-Rac signaling pathway acts in parallel with TLR4 engagement to control IKKβ activation for inflammatory cytokine release. Next, we investigated whether pharmacological inhibition of DOCK2 protects against endotoxemia-induced lung injury in mice. Treatment with 4-[3'-(2″-chlorophenyl)-2'-propen-1'-ylidene]-1-phenyl-3,5-pyrazolidinedione (CPYPP), a small-molecule inhibitor of DOCK2, reduced the severity of lung injury, as indicated by decreases in the lung injury score and myeloperoxidase (MPO) activity. Moreover, CPYPP attenuated LPS-induced proinflammatory cytokine release in mice. Our studies suggest that inhibition of DOCK2 may suppress LPS-induced macrophage activation and that DOCK2 may be a novel target for treating endotoxemia-related ALI.

Azilsartan Suppressed LPS-Induced Inflammation in U937 Macrophages through Suppressing Oxidative Stress and Inhibiting the TLR2/MyD88 Signal Pathway

BACKGROUND AND PURPOSE

Lipopolysaccharide (LPS) is an important factor that induce severe inflammation, resulting in multiple types of diseases. It is reported that LPS-induced inflammation is related to the activation of the NF-κB signal pathway and reactive oxygen species (ROS)-induced oxidative stress. Azilsartan, an angiotensin II type 1 (AT1) receptor blocker, has been licensed as a new generation of Sartan antihypertensive drugs. However, the effects of azilsartan in LPS-induced inflammation have not been reported before. The present study aims to investigate the anti-inflammatory effects of azilsartan on LPS-stimulated macrophages and explore the underlying mechanism.

METHODS

The release of lactic dehydrogenase (LDH), secretion of HMGB-1, and concentrations of IL-6, IL-1β, MCP-1, MMP-2, MMP-9, and PGE₂ were evaluated using the enzyme-linked immunosorbent assay (ELISA). The gene expression levels of IL-6, IL-1β, MCP-1, MMP-2, MMP-9, and COX-2 were determined by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Western blot analysis was used to detect the protein expression level of COX-2, Nrf2, TLR2, MyD-88, and NF-κB. The level of ROS was determined using the dihydroethidium (DHE) staining assay. The activity of NF-κB was evaluated using the luciferase activity assay.

RESULTS

The release of LDH, HMGB-1, IL-6, IL-1β, MCP-1, MMP-2, MMP-9, and PGE₂ was significantly promoted by LPS stimulation, whereas it was greatly suppressed by azilsartan. The upregulated COX-2, TLR2, MyD-88, and NF-κB in the LPS-treated macrophages were significantly downregulated by azilsartan. Interestingly, the expression level of Nrf2 was elevated by azilsartan. On the contrary, ROS levels were greatly increased by LPS but suppressed by azilsartan. Mechanistically, it was found that azilsartan suppressed LPS-induced activation of the TLR2/Myd-88/NF-κB signaling pathway.

CONCLUSION

Azilsartan might suppress LPS-induced inflammation in U937 macrophages through suppressing oxidative stress and inhibiting the TLR/MyD88 signal pathway.

Actin-granule formation is an additional step in cardiac myofibroblast differentiation

Background

Atrial fibrillation is the most common and long-lasting cardiac arrhythmia, and profoundly effects the daily lives of patients. The pathogenesis and persistence of atrial fibrillation is closely related to the cardiac fibroblast and its myofibroblast differentiation as increased collagen synthesis and migration capability. Thus better understanding of myofibroblast differentiation is essential for the prevention and treatment of atrial fibrillation.

Methods

Cardiac fibroblasts were isolated from neonatal rats and its actin structure was analyzed by immunofluorescence staining. Myofibroblast differentiation was induced by Angiotensin II (Ang II) and ROCK signaling related proteins were determined by western blot. Fasudil and Ricolinostat were employed to abrogate ROCK signaling and their effects on myofibroblast differentiation were assessed by IF microscopy and Celigo Image Cytometry.

Results

Stress actin fibers similar to actin filaments in myofibroblast differentiation are regulated by ROCK signaling, and our results also suggested Guanine nucleotide exchange factor-H1 (GEF-H1) phosphorylation could be induced by Ang II. In addition, Fasudil could down-regulate RhoA, GEF-H1, and phosphorylated GEF-H1 to inhibit ROCK signaling and further reduce Col I expression and the myofibroblast proportion.

Conclusions

An individual phase characterized by actin-granule formation was identified in cardiac myofibroblast differentiation. In the meanwhile, myofibroblast differentiation and its F-actin assembly could be detained in this phase by Fasudil abrogating the ROCK signaling pathway.

The immunoenhancement effects of starfish Asterias rollestoni polysaccharides in macrophages and cyclophosphamide-induced immunosuppression mouse models

The water-soluble polysaccharide, SF-2, obtained from starfish (Asterias rollestoni), belongs to the group of polysaccharides known as mannoglucan sulfate. It is composed of mannose as well as glucose and contains 13.85% SO₄^2-. We aimed to detect the immunoenhancement effects of SF-2 in macrophages and cyclophosphamide (CYP)-induced immunosuppression mouse models. RAW 264.7 macrophage cells were treated with SF-2 for different periods of time (0 h, 0.5 h, 1 h, 3 h, 6 h, and 9 h) and the results showed that SF-2 promoted the production of nitric oxide and up-regulated the levels of pro-inflammatory cytokines and related proteins, such as TNF-α, IL-1β, IL-6, COX-2, MMP-9, and iNOS in a time-dependent manner. In addition, SF-2 activated NLRP3 inflammasome and the MAPK/NF-κB signaling pathway, thus promoting its immunoenhancement effects. Moreover, we co-cultured the primary peritoneal macrophages with SF-2 for 6 h and found that SF-2 enhanced the expression of NLRP3 inflammasome and the release of cytokines. Furthermore, SF-2 significantly increased the body weight, spleen index, thymus index, and inflammatory cell counts in CYP-induced immunosuppression mouse models. These results indicate that SF-2 is a potential immunoenhancement mediator that acts by activating the NLRP3 inflammasome and MAPK/NF-κB pathway.

Role of Epigenetics in the Regulation of Immune Functions of the Skin

This review is intended to illuminate the emerging understanding of epigenetic modifications that regulate both adaptive and innate immunity in the skin. Host defense of the epidermis and dermis involves the interplay of many cell types to enable homeostasis; tolerance to the external environment; and appropriate response to transient microbial, chemical, and physical insults. To understand this process, the study of cutaneous immunology has focused on immune responses that reflect both adaptive learned and genetically programmed innate defense systems. However, recent advances have begun to reveal that epigenetic modifications of chromatin structure also have a major influence on the skin immune system. This deeper understanding of how enzymatic changes in chromatin structure can modify the skin immune system and may explain how environmental exposures during life, and the microbiome, lead to both short-term and long-term changes in cutaneous allergic and other inflammatory processes. Understanding the mechanisms responsible for alterations in gene and chromatin structure within skin immunocytes could provide key insights into the pathogenesis of inflammatory skin diseases that have thus far evaded understanding by dermatologists.

Targeting HDAC6 attenuates nicotine-induced macrophage pyroptosis via NF-κB/NLRP3 pathway

BACKGROUND AND AIMS

During the development of atherosclerosis, nicotine activates macrophage inflammation. However, whether nicotine induces macrophage pyroptosis and the underlying mechanisms remain unclear. This study aimed to investigate the role of histone deacetylase 6 (HDAC6) in nicotine-induced macrophage pyroptosis.

METHODS

For the in vivo study, nicotine was administered to 8-week-old ApoE^-/- mice fed a high-fat diet (HFD) for 12 weeks. TUNEL/CD68 and Caspase-1/CD68 staining was used to assess macrophage pyroptosis in plaque. For the in vitro study, Western blotting, lactic dehydrogenase activity (LDH), coimmunoprecipitation, chromatin immunoprecipitation and immunofluorescence were used to evaluate pyroptosis and related signaling pathway in RAW264.7 cells.

RESULTS

A high-fat diet and nicotine upregulated macrophage pyroptosis in atherosclerotic lesions. Nicotine promoted pyroptosis in RAW264.7 cells, as evidenced by increased expression of cleaved Caspase1, NLRP3, IL-1β, IL-18, and elevated LDH release. Inhibition of HDAC6 suppressed nicotine-induced pyroptosis, which is partly mediated by p65 acetylation and NLRP3 transcription. Silencing p65 or NLRP3 resulted in decreased pyroptosis in RAW264.7 cells.

CONCLUSIONS

Nicotine induces macrophage pyroptosis in atherosclerosis through HDAC6/NF-κB/NLRP3 signaling pathway.

Carbon black nanoparticles induce HDAC6-mediated inflammatory responses in 16HBE cells

Long-term inhalation of carbon black nanoparticles (CBNPs) leads to pulmonary inflammatory diseases. Histone deacetylase 6 (HDAC6) has been identified as an important regulator in the development of inflammatory disorders. However, the direct involvement of HDAC6 in CBNPs-induced pulmonary inflammatory responses remains unclear. To explore whether HDAC6 participates in CBNPs-induced pulmonary inflammation, human bronchial epithelial cell line (16HBE cells) was transfected with HDAC6 small interference RNA (siRNA) and then exposed to CBNPs at concentrations of 0, 25, and 50 µg/ml for 24 h. Intracellular HDAC6 and intraflagellar transport protein 88 (IFT88) mRNA and protein were determined by real-time polymerase chain reaction and Western blot, respectively. The secretions of inflammatory cytokines including interleukin (IL)-8, tumor necrosis factor (TNF)-α, IL-6, and IL-1β were measured by enzyme-linked immunosorbent assay. CBNPs induced a significant increase in the expressions of IL-8 and IL-6, accompanied by a high level of intracellular HDAC6 mRNA when compared with a blank control group (p < 0.05). However, there were no significant changes in the levels of TNF-α secretion, intracellular HDAC6 and IFT88 protein induced by CBNPs (p > 0.05). The HDAC6 mRNA expression was significantly suppressed in HDAC6 siRNA-transfected cells (p < 0.05). The secretions of IL-8, TNF-α, and IL-6 were significantly less in HDAC6 siRNA-transfected cells than that in normal 16HBE cells with exposure to 25 or 50 µg/ml of CBNPs, but intracellular IFT88 mRNA expression was markedly increased in HDAC6 siRNA-transfected cells when compared with normal 16HBE cells exposed to 50 µg/ml of CBNPs (all p < 0.05). Downregulation of the HDAC6 gene inhibits CBNPs-induced inflammatory responses in bronchial epithelial cells, partially through regulating IFT88 expression. It is suggested that CBNPs may trigger inflammatory responses in bronchial epithelial cells by an HDAC6/IFT88-dependent pathway.

The Primary Cilium as a Therapeutic Target in Ocular Diseases

Primary cilia are microtubule-based cellular structures located on the surfaces of most mammalian cells and play important roles in detecting external stimuli, signal transduction, and cell cycle regulation. Primary cilia are also present in several structures of the eye, and their abnormal development or dysfunction can cause various ocular diseases. The rapid development of proteomics and metabolomics technologies have helped in the identification of many ocular disease-related proteins, some of which are dysregulated in primary cilia. This review focuses on ciliary dysregulation in a number of ocular diseases and discusses the potential of targeting primary cilia in gene and stem cell therapy for these diseases.

Breaking the vicious loop between inflammation, oxidative stress and coagulation, a novel anti-thrombus insight of nattokinase by inhibiting LPS-induced inflammation and oxidative stress

Thrombosis is a principle cause of cardiovascular disease, the leading cause of morbidity and mortality worldwide; however, the conventional anti-thrombotic approach often leads to bleeding complications despite extensive clinical management and monitoring. In view of the intense crosstalk between inflammation and coagulation, plus the contributing role of ROS to both inflammation and coagulation, it is highly desirable to develop safer anti-thrombotic agent with preserved anti-inflammatory and anti-oxidative stress activities. Nattokinase (NK) possesses many beneficial effects on cardiovascular system due to its strong thrombolytic and anticoagulant activities. Herein, we demonstrated that NK not only effectively prevented xylene-induced ear oedema in mice, but also remarkably protected against LPS-induced acute kidney injury in mice through restraining inflammation and oxidative stress, a central player in the initiation and progression of inflammation. Fascinatingly, in line with our in vivo data, NK elicited prominent anti-inflammatory activity in RAW264.7 macrophages via suppressing the LPS-induced TLR4 and NOX2 activation, thereby repressing the corresponding ROS production, MAPKs activation, and NF-κB translocation from the cytoplasm to the nucleus, where it mediates the expression of pro-inflammatory mediators, such as TNF-α, IL-6, NO, and PAI-1 in activated macrophage cells. In particular, consistent with the macrophage studies, NK markedly inhibited serum PAI-1 levels induced by LPS, thereby blocking the deposition of fibrin in the glomeruli of endotoxin-treated animals. In summary, we extended the anti-thrombus mechanism of NK by demonstrating the anti-inflammatory and anti-oxidative stress effects of NK in ameliorating LPS-activated macrophage signaling and protecting against LPS-stimulated AKI as well as glomeruler thrombus in mice, opening a comprehensive anti-thrombus strategy by breaking the vicious cycle between inflammation, oxidative stress and thrombosis.

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NK protects against LPS-induced AKI via inhibiting inflammation and oxidative stress.

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NK inhibits LPS-induced TRL4 and NOX2 activation in macrophages.

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NK inhibits inflammation and oxidative stress both in vitro and in vivo.

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NK inhibits LPS-induced PAI-I levels, thereby blocking glomerular thrombus in mice.

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NK may break the vicious loop between inflammation, oxidative stress and coagulation.

Macrophage stimulating 1-induced inflammation response promotes aortic aneurysm formation through triggering endothelial cells death and activating the NF-κB signaling pathway

Aortic aneurysm formation is associated with endothelial cells dysfunction through an undefined mechanism. Macrophage stimulating 1 (Mst1) and NF-κB signaling pathway have been found to be related to inflammation response in endothelial cell damage. The goal of our study is to explore the role of Mst1 in regulating endothelial cell viability with a focus on NF-κB signaling pathway and inflammation response. Endothelial cell viability and death were determined via immunofluorescence and ELISA. Agonist of NF-κB signaling pathway and siRNA against Mst1 were used. The results in our study demonstrated that Mst1 transcription and expression were significantly elevated after exposure to oxidative stress in endothelial cells. Once loss of Mst1 through transfection of siRNA (si-Mst1), endothelial cell viability and survival rate were rapidly increased in response to oxidative stress. In addition, we also found that Mst1 controlled inflammation response and mitochondrial function in endothelial cells. Re-activation of NF-κB signaling pathway was followed by an activation of inflammation response and mitochondrial dysfunction, as evidenced by increased expression of inflammation factors and decreased ATP synthesis. Altogether, our results identify Mst1 as the primary factors responsible for endothelial cells dysfunction in aneurysms formation through inducing inflammation response, endothelial apoptosis, and NF-κB signaling pathway activation.

Schizandrin attenuates lung lesions induced by Avian pathogenic Escherichia coli in chickens

Avian pathogenic Escherichia coli (APEC) can cause serious pathological changes and inflammation in chickens. Schizandrin has anti-inflammatory activity and can prevent damage to various tissues and organs. The purpose of this study was to investigate the protective effect of schizandrin on APEC-induced lung lesions in chickens and explore the potential mechanism of schizandrin protection. The schizandrin (50, 100, and 200 mg/kg) was intragastrically administered for 3 days. APEC was administered using intraperitoneal (i.p.) injection to induce lung lesions. Then, chickens were sacrificed by CO2 inhalation 24 h later and the lung tissues were collected for examining histopathological changes, wet/dry (W/D) ratio, myeloperoxidase (MPO) activity, malondialdehyde (MDA), levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-8 and activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Our findings showed that schizandrin markedly inhibited pathological changes, pulmonary edema, MPO activity and MDA content. Moreover, schizandrin markedly reduced the levels of TNF-α, IL-1β, IL-6 and IL-8 in lung tissue. Importantly, the mechanism responsible for these effects was attributed to the inhibitory effect of schizandrin on NF-κB and MAPK signaling activation. In conclusion, our findings reveal that schizandrin displays anti-oxidant and anti-inflammatory activity against APEC-induced lung lesions in chickens, paving the way for rational use of schizandrin as a protective agent against lung-related inflammatory disease.