Artesunate Inhibits Renal Ischemia-Reperfusion-Mediated Remote Lung Inflammation Through Attenuating ROS-Induced Activation of NLRP3 Inflammasome

Inflammation in cerebral ischemia reperfusion improved by avanafil via nod-like receptor protein-3 inflammasome: an experimental study in rats

OBJECTIVE

The aim of study was to investigate the effect of avanafil, a second-generation phosphodiesterase-5 (PDE5) inhibitor, on cerebral ischemia reperfusion (CI/R) model.

METHODS

32 male albino Wistar rats were used. Four groups were constituted, as I: the healthy (sham), II: the CI/R group, III: the CI/R +I 10 mg/kg avanafil group, and IV: the CI/R + 20 mg/kg avanafil group. Avanafil was administered twice via oral gavage, first shortly after ischemia reperfusion and once more after 12 h. The rats were euthanized after 24 h. Histopathological and Real Time PCR analyzes were performed on cerebral tissues.

RESULTS

IL-1β, NLRP3 and TNF-α mRNA expressions were statistically higher in the CI/R group when compared to healthy (sham) group. Conversely, the IL-1β, NLRP3, and TNF-α mRNA expressions were significantly decreased in both of the avanafil-treated groups when compared to CI/R group. Histopathological results showed that both doses of avanafil also decreased cellular damage in cerebral tissue that occurred after CI/R.

CONCLUSION

Avanafil, was found to have ameliorated inflammatory response and cellular injury caused by CI/R. The mRNA expression of IL-1β, NLRP3, and TNF-α decreased in the I/R groups and approached the control group levels with a high dose of avanafil.

Role of mitochondrial stress and the NLRP3 inflammasome in lung diseases

BACKGROUND

As an organelle essential for intracellular energy supply, mitochondria are involved in intracellular metabolism and inflammation, and cell death. The interaction of mitochondria with the NLRP3 inflammasome in the development of lung diseases has been extensively studied. However, the exact mechanism by which mitochondria mediate the activation of the NLRP3 inflammasome and trigger lung disease is still unclear.

METHODS

The literatures related to mitochondrial stress, NLRP3 inflammasome and lung diseases were searched in PubMed.

RESULTS

This review aims to provide new insights into the recently discovered mitochondrial regulation of the NLRP3 inflammasome in lung diseases. It also describes the crucial roles of mitochondrial autophagy, long noncoding RNA, micro RNA, altered mitochondrial membrane potential, cell membrane receptors, and ion channels in mitochondrial stress and regulation of the NLRP3 inflammasome, in addition to the reduction of mitochondrial stress by nuclear factor erythroid 2-related factor 2 (Nrf2). The effective components of potential drugs for the treatment of lung diseases under this mechanism are also summarized.

CONCLUSION

This review provides a resource for the discovery of new therapeutic mechanisms and suggests ideas for the development of new therapeutic drugs, thus promoting the rapid treatment of lung diseases.

Artesunate Alleviates Hyperoxia-Induced Lung Injury in Neonatal Mice by Inhibiting NLRP3 Inflammasome Activation

Bronchopulmonary dysplasia (BPD) is a chronic respiratory disease in preterm infants that may cause persistent lung injury. Artesunate exhibits excellent anti-inflammatory in lung injury caused by various factors. This study aimed to investigate the effect of the artesunate on hyperoxia-induced lung injury in neonatal mice and its mechanism. A BPD model of hyperoxic lung injury in neonatal mice was established after hyperoxia (75% oxygen) exposure for 14 days, and part of the mice received intraperitoneal injections of the artesunate. H&E staining was used to observe the pathology of lung tissue, and the degree of oxidative stress in the lung tissue was determined by commercial kits. The levels of inflammatory cytokines in the serum and lung tissues of neonatal mice were detected by an enzyme-linked immunosorbent assay. Immunohistochemical experiments were performed to further evaluate the expression of IL-1β. The real-time quantitative polymerase chain reaction was used to determine the mRNA level of the NLRP3 inflammasome. The western blot assay was used to measure the levels of NLRP3 inflammasome and NF-κB pathway-related proteins. Artesunate ameliorated weight loss and lung tissue injury in neonatal mice induced by hyperoxia. The level of malondialdehyde was decreased, while the activity of superoxide dismutase and the level of glutathione increased after artesunate treatment. Artesunate reduced the level of inflammation cytokines TNF-α, IL-6, and IL-1β in the serum and lung. Moreover, artesunate inhibited the mRNA expression and protein levels of NLRP3, ASC, and caspase-1, as well as the phosphorylation of the NF-κB and IκBα. Our findings suggest that artesunate treatment can attenuate hyperoxia-induced lung injury in BPD neonatal mice by inhibiting the activation of NLRP3 inflammasome and the phosphorylation of the NF-κB pathway.

Astragaloside IV ameliorates spinal cord injury through controlling ferroptosis in H2O2-damaged PC12 cells in vitro

BACKGROUND

Spinal cord injury (SCI) is associated with significant paralysis and high fatality. Recent research has revealed that ferroptosis participates in the pathogenesis of SCI. Astragaloside IV (AS-IV), the main active ingredient of the plant Astragalus membranaceus, has been reported to promote motor function recovery in rats with SCI. This study explored the effects of AS-IV in H2O2-treated PC12 pheochromocytoma cells.

METHODS

The optimal concentration and duration of AS-IV treatment in PC12 cells was assessed using the cell counting kit 8 (CCK-8) assay. Subsequently, the SCI cell model was established in PC12 cells using H2O2. The effects of AS-IV, FIN56, and transcription factor EB (TFEB) small interfering (si)RNA on cell viability and apoptosis in the SCI model were determined using the CCK-8 assay and flow cytometry, respectively. Caspase‑3 and lactate dehydrogenase (LDH) levels were measured by colorimetric assay and enzyme-linked immunosorbent assay (ELISA), respectively. Cellular reactive oxygen species (ROS) were detected by flow cytometry combined with dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay. The cellular ultrastructure was analyzed by transmission electron microscopy (TEM). The ferroptosis pathway-related proteins were confirmed using Western blot analysis. TFEB expression was confirmed by Western blot and immunofluorescence.

RESULTS

The optimal concentration and duration of AS-IV treatment in PC12 cells was determined to be 1.0 µM and 48 h, respectively. AS-IV markedly accelerated proliferation, suppressed apoptosis, and reduced ROS and LDH accumulation. Furthermore, AS-IV enhanced TFEB expression in H2O2-damaged PC12 cells. The effects of AS-IV on SCI were inhibited by si-TFEB, and this inhibition was further reinforced by the addition of FIN56.

CONCLUSIONS

The results of this investigation using the SCI cell model suggested that AS-IV alleviated SCI by promoting TFEB expression and subsequently mediating ferroptosis. This may represent a potential clinical treatment for SCI.

Pyroptosis and respiratory diseases: A review of current knowledge

Pyroptosis is a relatively newly discovered programmed cell death accompanied by an inflammatory response. In the classical view, pyroptosis is mediated by caspases-1,-4,-5,-11 and executed by GSDMD, however, recently it was demonstrated that caspase-3 and-8 also participate in the process of pyroptosis, by cleaving GSDMD/E and GSDMD respectively. Different from autophagy and apoptosis, many pores are formed on the cell membrane during pyroptosis, which makes the cell membrane lose its integrity, eventually leading to the release of cytokines interleukin(IL)-1β and IL-18. When the body is infected with pathogens or exposed to some stimulations, pyroptosis could play an immune defense role. It is found that pyroptosis exists widely in infectious and inflammatory respiratory diseases such as acute lung injury, bronchial dysplasia, chronic obstructive pulmonary disease, and asthma. Excessive pyroptosis may accompany airway inflammation, tissue injury, and airway damage, and induce an inflammatory reaction, leading to more serious damage and poor prognosis of respiratory diseases. This review summarizes the relationship between pyroptosis and related respiratory diseases.

Engineering plant family TPS into cyanobacterial host for terpenoids production

Terpenoids are synthesized naturally by plants as secondary metabolites, and are diverse and complex in structure with multiple applications in bioenergy, food, cosmetics, and medicine. This makes the production of terpenoids such as isoprene, β-phellandrene, farnesene, amorphadiene, and squalene valuable, owing to which their industrial demand cannot be fulfilled exclusively by plant sources. They are synthesized via the Methylerythritol phosphate pathway (MEP) and the Mevalonate pathway (MVA), both existing in plants. The advent of genetic engineering and the latest accomplishments in synthetic biology and metabolic engineering allow microbial synthesis of terpenoids. Cyanobacteria manifest to be the promising hosts for this, utilizing sunlight and CO2. Cyanobacteria possess MEP pathway to generate precursors for terpenoid synthesis. The terpenoid synthesis can be amplified by overexpressing the MEP pathway and engineering MVA pathway genes. According to the desired terpenoid, terpene synthases unique to the plant kingdom must be incorporated in cyanobacteria. Engineering an organism to be used as a cell factory comes with drawbacks such as hampered cell growth and disturbance in metabolic flux. This review set forth a comparison between MEP and MVA pathways, strategies to overexpress these pathways with their challenges.

Artesunate: A review of its therapeutic insights in respiratory diseases

BACKGROUND

Artesunate, as a semi-synthetic artemisinin derivative of sesquiterpene lactone, is widely used in clinical antimalarial treatment due to its endoperoxide group. Recent studies have found that artesunate may have multiple pharmacological effects, indicating its significant therapeutic potential in multiple respiratory diseases.

PURPOSE

This review aims to summarize proven and potential therapeutic effects of artesunate in common respiratory disorders.

STUDY DESIGN

This review summarizes the pharmacological properties of artesunate and then interprets the function of artesunate in various respiratory diseases in detail, such as bronchial asthma, chronic obstructive pulmonary disease, lung injury, lung cancer, pulmonary fibrosis, coronavirus disease 2019, etc., on different target cells and receptors according to completed and ongoing in silico, in vitro, and in vivo studies (including clinical trials).

METHODS

Literature was searched in electronic databases, including Pubmed, Web of Science and CNKI with the primary keywords of 'artesunate', 'pharmacology', 'pharmacokinetics', 'respiratory disorders', 'lung', 'pulmonary', and secondary search terms of 'Artemisia annua L.', 'artemisinin', 'asthma', 'chronic obstructive lung disease', 'lung injury', 'lung cancer', 'pulmonary fibrosis', 'COVID-19' and 'virus' in English and Chinese. All experiments were included. Reviews and irrelevant studies to the therapeutic effects of artesunate on respiratory diseases were excluded. Information was sort out according to study design, subject, intervention, and outcome.

RESULTS

Artesunate is promising to treat multiple common respiratory disorders via various mechanisms, such as anti-inflammation, anti-oxidative stress, anti-hyperresponsiveness, anti-proliferation, airway remodeling reverse, induction of cell death, cell cycle arrest, etc. CONCLUSION: Artesunate has great potential to treat various respiratory diseases.

The Protective Effect of Artesunate on LPS-Induced Acute Respiratory Distress Syndrome through Inhibiting NLRP3 Inflammasome Signaling

Background

Artesunate (AS) is a derivative of artemisinin that can exert anti-inflammatory effects. This study aims to explore the effect of AS on lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS).

Methods

The newborn mice were used for experimental ARDS model establishment by intraperitoneal injection of LPS (10 mg/kg) into mice with or without AS (20 mg/kg) pretreatment. After that, the pathological morphology of mouse lung tissue was observed by H&E staining. The content of inflammatory factors in serum was measured by ELISA and mRNA expression and lung tissue was determined by qRT-PCR. The expression of NLRP3 inflammasome and related proteins in lung tissue was confirmed by immunohistochemistry and Western blot.

Results

AS treatment effectively alleviated the LPS-induced lung injury and pulmonary edema, and reduced the expression of IL-1β, IL-18, IL-6, IL-8, MCP-1, and TNF-α in serum and lung tissues of experimental ARDS mice. In addition, AS treatment reduced the expression of NLRP3, ASC, and caspase-1 in lung tissues of experimental ARDS mice.

Conclusion

AS alleviated LPS-induced lung injury in ARDS mice by inhibiting the activation of NLRP3 inflammasome.

Effects of propofol on macrophage activation and function in diseases

Macrophages work with monocytes and dendritic cells to form a monocyte immune system, which constitutes a powerful cornerstone of the immune system with their powerful antigen presentation and phagocytosis. Macrophages play an essential role in infection, inflammation, tumors and other pathological conditions, but these cells also have non-immune functions, such as regulating lipid metabolism and maintaining homeostasis. Propofol is a commonly used intravenous anesthetic in the clinic. Propofol has sedative, hypnotic, anti-inflammatory and anti-oxidation effects, and it participates in the body’s immunity. The regulation of propofol on immune cells, especially macrophages, has a profound effect on the occurrence and development of human diseases. We summarized the effects of propofol on macrophage migration, recruitment, differentiation, polarization, and pyroptosis, and the regulation of these propofol-regulated macrophage functions in inflammation, infection, tumor, and organ reperfusion injury. The influence of propofol on pathology and prognosis via macrophage regulation is also discussed. A better understanding of the effects of propofol on macrophage activation and function in human diseases will provide a new strategy for the application of clinical narcotic drugs and the treatment of diseases.

Artemisinin inhibits neutrophil and macrophage chemotaxis, cytokine production and NET release

Immune cell chemotaxis to the sites of pathogen invasion is critical for fighting infection, but in life-threatening conditions such as sepsis and Covid-19, excess activation of the innate immune system is thought to cause a damaging invasion of immune cells into tissues and a consequent excessive release of cytokines, chemokines and neutrophil extracellular traps (NETs). In these circumstances, tempering excessive activation of the innate immune system may, paradoxically, promote recovery. Here we identify the antimalarial compound artemisinin as a potent and selective inhibitor of neutrophil and macrophage chemotaxis induced by a range of chemotactic agents. Artemisinin released calcium from intracellular stores in a similar way to thapsigargin, a known inhibitor of the Sarco/Endoplasmic Reticulum Calcium ATPase pump (SERCA), but unlike thapsigargin, artemisinin blocks only the SERCA3 isoform. Inhibition of SERCA3 by artemisinin was irreversible and was inhibited by iron chelation, suggesting iron-catalysed alkylation of a specific cysteine residue in SERCA3 as the mechanism by which artemisinin inhibits neutrophil motility. In murine infection models, artemisinin potently suppressed neutrophil invasion into both peritoneum and lung in vivo and inhibited the release of cytokines/chemokines and NETs. This work suggests that artemisinin may have value as a therapy in conditions such as sepsis and Covid-19 in which over-activation of the innate immune system causes tissue injury that can lead to death.

Artemisinin and Its Derivate Alleviate Pulmonary Hypertension and Vasoconstriction in Rodent Models

Background

Pulmonary arterial hypertension (PAH) is a complex pulmonary vasculature disease characterized by progressive obliteration of small pulmonary arteries and persistent increase in pulmonary vascular resistance, resulting in right heart failure and death if left untreated. Artemisinin (ARS) and its derivatives, which are common antimalarial drugs, have been found to possess a broad range of biological effects. Here, we sought to determine the therapeutic benefit and mechanism of ARS and its derivatives treatment in experimental pulmonary hypertension (PH) models.

Methods

Isolated perfused/ventilated lung and isometric tension measurements in arteries were performed to test pulmonary vasoconstriction and relaxation. Monocrotaline (MCT) and hypoxia+Su5416 (SuHx) were administered to rats to induce severe PH. Evaluation methods of ARS treatment and its derivatives in animal models include echocardiography, hemodynamics measurement, and histological staining. In vitro, the effect of these drugs on proliferation, viability, and hypoxia-inducible factor 1α (HIF1α) was examined in human pulmonary arterial smooth muscle cells (hPASMCs).

Results

ARS treatment attenuated pulmonary vasoconstriction induced by high K⁺ solution or alveolar hypoxia, decreased pulmonary artery (PA) basal vascular tension, improved acetylcholine- (ACh-) induced endothelial-dependent relaxation, increased endothelial nitric oxide (NO) synthase (eNOS) activity and NO levels, and decreased levels of NAD(P)H oxidase subunits (NOX2 and NOX4) expression, NAD(P)H oxidase activity, and reactive oxygen species (ROS) levels of pulmonary arteries (PAs) in MCT-PH rats. NOS inhibitor, L-NAME, abrogated the effects of ARS on PA constriction and relaxation. Furthermore, chronic application of both ARS and its derivative dihydroartemisinin (DHA) attenuated right ventricular systolic pressure (RVSP), Fulton index (right ventricular hypertrophy), and vascular remodeling of PAs in the two rat PH models. In addition, DHA inhibited proliferation and migration of hypoxia-induced PASMCs.

Conclusions

In conclusion, these results indicate that treatment with ARS or DHA can inhibit PA vasoconstriction, PASMC proliferation and migration, and vascular remodeling, as well as improve PA endothelium-dependent relaxation, and eventually attenuate the development and progression of PH. These effects might be achieved by decreasing NAD(P)H oxidase generated ROS production and increasing eNOS activation to release NO in PAs. ARS and its derivatives might have the potential to be novel drugs for the treatment of PH.

Paraquat Induces Lung Injury via miR-199-Mediated SET in a Mouse Model

Objective: To explore the molecular mechanism of lung injury caused by paraquat (PQ) poisoning by investigating miR-199-mediated SET.

Methods: A paraquat poisoning model was established in C57BL/6 male mice via intraperitoneal injection of paraquat. The mice were transfected with miR-199 siRNA and or mimic. After 14 days of treatment, pathophysiological changes of the lung were observed and lung tissue was analyzed via Hematoxylin-Eosin staining. The levels of miR-199, SETs, surfactant protein SP-A and SP-B, and inflammatory and oxidative factors were analyzed by qPCR, Western Blot, and ELISA kits.

Results: A acute lung-injury (ALI) model was established using PQ treatment and confirmed with edema of pulmonary endothelium with low electronic density of endothelial cytoplasm, presence of protein-rich fluid, and numerous erythrocytes in alveolar space, concentric figures of damaged tubular myelin, alveolar destruction, and increase in inflammatory cell numbers. Compared with the control group, miR-199 and SET levels were reduced in the PQ-treated group. miR-199 siRNA increased the SET level, inflammatory and oxidative levels, and reduced the levels of SP-A and SP-B, and miR-199 mimic reduced the SET level, inflammatory and oxidative levels, and increased the levels of SP-A and SP-B. PQ treatment reduced miR-199 level.

Conclusion: Paraquat induces ALI by affecting miR-199-mediated SET.

Anti-inflammatory effects of artesunate on atherosclerosis via miR-16-5p and TXNIP regulation of the NLRP3 inflammasome

Background

Atherosclerosis (AS) is chronic inflammatory arterial disorder. Artesunate could exhibit anti-inflammatory activity in AS, but its role in AS is still in its incipient stage. In this study, we explored the anti-inflammatory effect of artesunate in AS and its underlying mechanism.

Methods

We isolated CD14⁺ monocytes from peripheral blood (PB) of 115 coronary heart disease (CHD) patients and 33 non-CHD patients confirmed by coronary angiography. Phorbol myristate acetate (PMA) was used to induce the differentiation of THP-1 monocytes to macrophages. Cells were treated with artesunate at a final concentration of 2.5, 5 or 10 µmol/L. The activation of NLRP3 inflammasome was assessed by immunoblotting of apoptosis-associated speck-like protein containing caspase recruitment domain (ASC). The expression of pro-caspase-1/pro-interleukin (IL)-1β/pro-IL-18 and their mature forms was measured using immunoblotting. A rat model of AS was induced by vitamin D3 (VD3) and a 21-day high-fat diet.

Results

Downregulated miR-16-5p and upregulated thioredoxin-interacting protein (TXNIP) was determined in CD14⁺ monocytes from CHD patients and associated with disease severity. Artesunate abrogated the activation of NLRP3 inflammasome in the presence of inflammasome activators in cultured macrophages. Artesunate reduced TXNIP expression and impaired the interaction between TXNIP and NLRP3, thereby inhibiting release of inflammatory cytokines and ASC production in cultured macrophages. In addition, miR-16-5p negatively regulated the messenger RNA (mRNA) of TXNIP. Artesunate increased the expression of miR-16-5p in a dose-dependent manner, and inhibition of miR-16-5p enhanced the secretion of inflammatory cytokines. Our in vivo experiments also demonstrated that artesunate reduced lipid accumulation, atherosclerotic plaque formation, and antagonized inflammation in a dose-dependent manner by upregulating miR-16-5p.

Conclusions

In summary, the present study unveiled a mechanism underlying the anti-inflammatory role of artesunate in AS.

Artemisinin Improves Acetylcholine-Induced Vasodilatation in Rats with Primary Hypertension

Purpose

Endothelial dysfunction and the subsequent decrease in endothelium-dependent vascular relaxation of small arteries are major features of hypertension. Artemisinin, a well-known antimalarial drug, has been shown to exert protecting roles against endothelial cell injury in cardiac and pulmonary vascular diseases. The current study aimed to investigate the effects of artemisinin on endothelium-dependent vascular relaxation and arterial blood pressure, as well as the potential signalling pathways in spontaneously hypertensive rats (SHRs).

Methods

In this study, acetylcholine (ACh)-induced dose-dependent relaxation assays were performed to evaluate vascular endothelial function after treatment with artemisinin. Artemisinin was administered to the rats by intravenous injection or to arteries by incubation for the acute exposure experiments, and it was administered to rats by intraperitoneal injection for 28 days for the chronic experiments.

Results

Both acute and chronic administration of artemisinin decreased the heart rate and improved ACh-induced endothelium-dependent relaxation but negligibly affected the arterial blood pressure in SHRs. Incubation with artemisinin decreased basal vascular tension, NAD(P)H oxidase activity and reactive oxygen species (ROS) levels, but it also increased endothelial nitric oxide (NO) synthase (eNOS) activity and NO levels in the mesenteric artery, coronary artery, and pulmonary artery of SHRs. Artemisinin chronic administration to SHRs increased the protein expression of eNOS and decreased the protein expression of the NAD(P)H oxidase subunits NOX-2 and NOX-4 in the mesenteric artery.

Conclusion

These results indicate that treatment with artemisinin has beneficial effects on reducing the heart rate and basal vascular tension and improving endothelium-dependent vascular relaxation in hypertension, which might occur by increasing eNOS activation and NO release and inhibiting NAD(P)H oxidase derived ROS production.

Penehyclidine hydrochloride ameliorates renal ischemia reperfusion-stimulated lung injury in mice by activating Nrf2 signaling

Introduction: Penehyclidine hydrochloride (PHC) is an anticholinergic with anti-inflammatory and anti-oxidation activities. PHC displayed protectivity against renal ischemia reperfusion (RIR) injury. Nevertheless, the precise protectivity of PHC on RIR-induced lung injury remains unknown. Methods: We examined the effects of PHC on RIR-induced lung injury and investigated the underlying mechanism. We induced RIR in mice and administrated PHC to RIR mice. Kidney function was monitored by measuring the blood urea nitrogen (BUN) and creatinine level in serum. We evaluated the lung injury, myeloperoxidase (MPO) activity in lung, pro-inflammatory cytokine level, and oxidative markers in serum and lung tissues. We tested the expression level of nuclear factor erythroid 2-related factor 2 (Nrf-2) and heme oxygenase 1 (HO-1) in lung of RIR mice after PHC treatment. Finally, we evaluated the effects of PHC in RIR Nrf2^-/- mice. Results: PHC greatly downregulated the serum levels of BUN, creatinine, IL-6, NO, malondialdehyde (MDA), and matrix metalloproteinase-2. PHC also ameliorated the lung injury, decreased the MPO activity, and suppressed production of IL-6, TNF-α, IFN-γ, MDA, and O2-, while it promoted production of superoxide dismutase (SOD) and catalase (CAT) in lung. PHC improved the production of Nrf2 and HO-1. Conclusion: The protectivity of PHC was absent in Nrf2^-/- mice. PHC ameliorated RIR-induced lung injury through Nrf2 pathway.

The Protective Activity of Penehyclidine Hydrochloride against Renal Ischemia/Reperfusion-Mediated NLRP3 Inflammasome Activation is Induced by SIRT1

Background: The activation of alveolar macrophages (AMs) modulated via leucine-rich repeat (NLR) pyrin domain containing 3 (NLRP3) inflammasome activation is key to the progression of renal ischemia/reperfusion (rI/R)-mediated acute lung injury (ALI). Sirtuin-1 (SIRT1) can attenuate NLRP3 inflammasome activation during I/R stress and may be an important mechanism underlying ALI pathogenesis. Penehyclidine hydrochloride (PHC), an anticholinergic drug, exerts protective effects against rI/R-mediated ALI. This study aimed to decipher the effects of PHC on SIRT1 activation and the underlying mechanism of the protective activity of PHC against rI/R-mediated ALI.Materials and methods: We used an ALI rat model and the rat AMs cell line NR8383 to assess the degree of lung injury in vivo and in vitro.Results: The results show that PHC attenuates rI/R-mediated lung injury indices, myeloperoxidase, and apoptosis in vivo. It decreases the rI/R-mediated release of prostaglandin E2 and nitric oxide, mitochondrial reactive oxygen species production, and the activity of NADPH oxidase-4 in vitro. PHC ameliorates the rI/R-induced activation of the thioredoxin-interacting protein, caspase 1 (P10 unit), and NLRP3 inflammasome, along with reduced activation of interleukin-1β and interleukin-18 in vitro. We show that PHC alleviates the rI/R-induced reduction of SIRT1 and the depletion of SIRT1 eliminates the ameliorating activity of PHC on the NLRP3 inflammasome activation in vitro. Conclusions: In summary, the findings suggest that PHC ameliorates the rI/R-mediated ALI through the SIRT1-mediated NLRP3 inflammasome activation.

The immunosuppressive activity of artemisinin-type drugs towards inflammatory and autoimmune diseases

The sesquiterpene lactone artemisinin from Artemisia annua L. is well established for malaria therapy, but its bioactivity spectrum is much broader. In this review, we give a comprehensive and timely overview of the literature regarding the immunosuppressive activity of artemisinin-type compounds toward inflammatory and autoimmune diseases. Numerous receptor-coupled signaling pathways are inhibited by artemisinins, including the receptors for interleukin-1 (IL-1), tumor necrosis factor-α (TNF-α), β3-integrin, or RANKL, toll-like receptors and growth factor receptors. Among the receptor-coupled signal transducers are extracellular signal-regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK), phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), AKT serine/threonine kinase (AKT), mitogen-activated protein kinase (MAPK)/extracellular signal regulated kinase (ERK) kinase (MEK), phospholipase C γ1 (PLCγ), and others. All these receptors and signal transduction molecules are known to contribute to the inhibition of the transcription factor nuclear factor κ B (NF-κB). Artemisinins may inhibit NF-κB by silencing these upstream pathways and/or by direct binding to NF-κB. Numerous NF-κB-regulated downstream genes are downregulated by artemisinin and its derivatives, for example, cytokines, chemokines, and immune receptors, which regulate immune cell differentiation, apoptosis genes, proliferation-regulating genes, signal transducers, and genes involved in antioxidant stress response. In addition to the prominent role of NF-κB, other transcription factors are also inhibited by artemisinins (mammalian target of rapamycin [mTOR], activating protein 1 [AP1]/FBJ murine osteosarcoma viral oncogene homologue [FOS]/JUN oncogenic transcription factor [JUN]), hypoxia-induced factor 1α (HIF-1α), nuclear factor of activated T cells c1 (NF-ATC1), Signal transducers and activators of transcription (STAT), NF E2-related factor-2 (NRF-2), retinoic-acid-receptor-related orphan nuclear receptor γ (ROR-γt), and forkhead box P-3 (FOXP-3). Many in vivo experiments in disease-relevant animal models demonstrate therapeutic efficacy of artemisinin-type drugs against rheumatic diseases (rheumatoid arthritis, osteoarthritis, lupus erythematosus, arthrosis, and gout), lung diseases (asthma, acute lung injury, and pulmonary fibrosis), neurological diseases (autoimmune encephalitis, Alzheimer's disease, and myasthenia gravis), skin diseases (dermatitis, rosacea, and psoriasis), inflammatory bowel disease, and other inflammatory and autoimmune diseases. Randomized clinical trials should be conducted in the future to translate the plethora of preclinical results into clinical practice.

Artesunate Attenuated the Progression of Abdominal Aortic Aneurysm in a Mouse Model

BACKGROUND

The inflammatory reaction is an important mechanism of pathogenesis of abdominal aortic aneurysm (AAA). Artesunate (AS) has been found to have anti-inflammatory effects in cardiovascular disease. The purpose of this study was to investigate whether AS could inhibit the development of AAA.

MATERIALS AND METHODS

AngII infused ApoE (-/-) male mice were selected as AAA model. Mice were spilt into three groups, the experimental control group (AngII), the AS treatment group (AngII + AS) and the negative control group (Vehicle) with 14 in each group. Daily administration of AS (100 mg/kg/d) or vehicle performed 3 day before the perfusion. At the end of the 28-day experiment, animal ultrasound and electronic digital caliper were used to measure the diameter of abdominal aorta. Histologic assays were performed to observe the microstructure of the aorta wall. Immunofluorescence staining was performed to detect inflammatory cells, as well as the levels of matrix metalloproteinases (MMPs). The transcription of cytokines and adhesion molecules were investigated by real-time fluorescence quantitative PCR (qPCR). Western blotting was performed to determine whether the NF-κB pathway is involved in the mechanism.

RESULTS

While AS failed to reduce the incidence of AAA, AS effectively reduced the diameter of AAA independently of blood pressure effects. Immunofluorescence detection showed that AS effectively reduced the levels of CD45+ cells and MAC3+ macrophages as well as MMP-2 and MMP-9. qPCR revealed that AS reduced mRNA transcription levels of MMP-2, MMP-9, the cytokine IL-1β, TNF-α, adhesion molecules ICAM-1, VCAM-1. AS decreased the levels of NF-κB signaling pathway in aorta.

CONCLUSIONS

AS can attenuate the development of AAA in mice. The possible mechanism is anti-inflammation.

Propofol ameliorates renal ischemia/reperfusion injury by enhancing macrophage M2 polarization through PPARγ/STAT3 signaling

Propofol (Pro) confers protection against renal ischemia/reperfusion (rI/R) injury through incompletely characterized mechanisms. Since Pro has shown net anti-inflammatory properties as part of its beneficial effects, we examined the potential role of Pro in the modulation of macrophage polarization status during both rI/R injury in vivo and exposure of cultured peritoneal macrophages (PMs) to hypoxia/reoxygenation (H/R). Rats were subjected to 45-min r/IR surgery or a sham procedure and administered PBS (vehicle) or Pro during the ischemia stage. Pro administration attenuated rI/R-induced kidney damage and renal TNF-α, IL-6, and CXCL-10 expression. Enhanced macrophage M2 polarization, evidenced by reduced iNOS and increased Arg1 and Mrc1 mRNA levels, was further detected after Pro treatment both in the kidney, after rI/R in vivo, and in H/R-treated PMs. Pro administration also repressed phosphorylated signal transducer and activator of transcription 1 (p-STAT1) and increased p-STAT3, p-STAT6, and peroxisome proliferator-activated receptor-γ (PPARγ) mRNA levels in H/R-exposed PMs. Importantly, siRNA-mediated PPARγ silencing repressed Pro-mediated STAT3 activation in PMs and restored proinflammatory cytokine levels and prevented macrophage M2 marker expression in both rI/R-treated rats and cultured PMs. These findings suggest that Pro confers renoprotection against rI/R by stimulating PPARγ/STAT3-dependent macrophage conversion to the M2 phenotype.

Artesunate Provides Neuroprotection against Cerebral Ischemia-Reperfusion Injury via the TLR-4/NF-κB Pathway in Rats

Inflammation has an important role in ischemia-reperfusion (I/R) injury. Artesunate (ART) has anti-microbial and anti-inflammatory pharmacological activities, and it is used for various types of serious malaria, including cerebral malaria. ART maintains a high concentration in the brain but little is known about the neuroprotective effect of ART against brain I/R injury. We studied the neuroprotection of ART against brain I/R injury and its underlying mechanism. In this study, rats were subjected to middle cerebral artery occlusion (MCAO) for 2 h. After 24 h of reperfusion, neurological deficits, cerebrum water content, infarct volume, hematoxylin-eosin (H&E)-staining, myeloperoxidase (MPO) activity, and proinflammatory cytokine levels were measured. Administration of 20, 40, 80, and 160 mg/kg ART intraperitoneally (i.p.) 10 min after MCAO significantly decreased brain water content and improved neurological deficits in a dose-dependent manner. An 80 mg/kg dosage was optimal. ART significantly reduced infarct volume, suppressed MPO activity and diminished the expressions of toll-like receptor (TLR)-4, MyD88, nuclear factor-κB (NF-κB), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in the area of the ischemic cortex. The neuroprotective action of ART against focal cerebral I/R injury might be due to the attenuation of inflammation through the TLR-4/NF-κB pathway.

Artesunate attenuates bone erosion in rheumatoid arthritis by suppressing reactive oxygen species via activating p62/Nrf2 signaling

Accumulating studies have indicated that reactive oxygen species (ROS) may be implicated into the destructive pathological events of rheumatoid arthritis (RA). As an effective antioxidant, artesunate (ARS) was reported to exert antiarthritic effects. However, whether ARS attenuates the bone erosion during RA progression by regulating ROS production remains to be defined. To address this problem, the inhibitive effects of ARS on osteoclastogenesis were observed in vitro. Mechanically, ARS significantly inhibited the NFATc1 signaling accompanied by markedly suppressing ROS production, which was abnormally enhanced during the pathological process of bone erosion. In addition, ARS may function as a potent ROS scavenger and significantly elevate the expression of HO-1 and NQO1 by activating Nrf2. Moreover, p62 accumulation induced by ARS was responsible for the activation of Nrf2, while the knockdown of p62 in osteoclast precursor cells diminished the suppressive effect of ARS on ROS production during osteoclastogenesis. Consistently, we also demonstrated that ARS effectively suppressed ROS production, leading to the inhibition of arthritic bone destruction by activating antioxidant enzyme and Nrf2/p62 signaling in the knee and ankle tissues of CIA rats. Collectively, our data offer the convincing evidence that ARS may inhibit osteoclastogenesis and ameliorate arthritic bone erosion through suppressing the generation of ROS via activating the p62/Nrf2 signaling.

Ameliorative effect of umbelliferone in remote organ injury induced by renal ischemia-reperfusion in rats

We evaluated the ameliorative role of umbelliferone in kidney, heart, and lung damage induced by renal ischemia/reperfusion (I/R) injury in rats. Umbelliferone was given orally to rats 60 min before ischemia. Ischemia was induced for 50 min and then reperfusion for 3 hr. The antioxidant enzymes, myeloperoxidase (MPO) activity, malondialdehyde (MDA) content, and cytokine levels in the kidney, heart, and lung were measured by ELISA. Moreover, histopathological changes were monitored. Renal I/R-induced oxidative stress in the organs by decreasing antioxidant enzymes. However, umbelliferone pretreatment enhanced superoxide dismutase (SOD) and glutathione (GSH), levels, reduced MDA and MPO levels. Renal I/R increased in tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) levels, and histopathological changes but these effects were inhibited with umbelliferone pretreatment. Furthermore, umbelliferone increased in nitric oxide synthase (eNOS) level under ischemia conditions. Our results indicated that pretreatment of umbelliferone-ameliorated damages in remote organ induced by renal I/R through suppressing oxidative stress and modulating inflammatory responses. PRACTICAL APPLICATIONS: kidney, heart, and lung damages induced by renal I/R in rats was alleviated by umbelliferone. The oral treatment of umbelliferone markedly reversed the oxidative stress, inflammation, and histopathological changes by increasing in the levels of SOD, GSH, and eNOS, decreasing in the levels of MDA, MPO, TNF-α, and IL-6 in distant organ injury induced by renal I/R. This study firstly revealed that umbelliferone has potent antioxidant and anti-inflammatory activity in the remote organ damages caused by renal I/R. Consequently, umbelliferone may be an alternative therapeutic agent for treating renal I/R-induced damages.

Inhibition of Peptidyl Arginine Deiminase-4 Prevents Renal Ischemia-Reperfusion-Induced Remote Lung Injury

Ischemia reperfusion (IR) can lead to acute kidney injury and can be complicated by acute lung injury, which is one of the leading causes of acute kidney injury-related death. Peptidyl arginine deiminase-4 (PAD4) is a member of the PAD enzyme family and plays a critical role in inflammatory reactions and neutrophil extracellular trap formation in a variety of pathological conditions. It has been reported that PAD4 inhibition can protect certain organs from ischemic injury. In this study, we aimed to understand the mode of action of PAD4 in renal ischemia-reperfusion-mediated acute lung injury. Bilateral renal pedicle occlusion was induced for 30 min followed by reperfusion for 24 h. A specific inhibitor of PAD4, GSK484, was delivered via intraperitoneal injection to alter the PAD4 activity. The pulmonary PAD4 expression, pulmonary impairment, neutrophil infiltration, Cit-H3 expression, neutrophil extracellular trap formation, inflammatory cytokine secretion, and pulmonary apoptosis were analyzed. We found that renal ischemia reperfusion was associated with pulmonary pathological changes and increases in neutrophil infiltration, neutrophil extracellular trap formation, and inflammatory cytokine secretion in the lungs of the recipient animals. Suppression of PAD4 by GSK484 reduced remote lung injury by mitigating neutrophil infiltration, neutrophil extracellular trap formation, apoptosis, and inflammatory factor secretion. Our findings demonstrate that specific PAD4 inhibition by GSK484 may be an effective strategy to attenuate distant lung injury complicating renal ischemia-reperfusion injury.

Could Artesunate Have a Positive Effect on the Neurological Complications Related to Infection When It Is Used in the Treatment of COVID-19?

Artesunate is a safe noncytotoxic drug with low side effects which is used in the treatment of chloroquine-resistant malaria. In addition to being an antimalarial drug, artesunate also has immunomodulatory, anticarcinogenic, and antiviral activity. There are in vivo and in vitro studies reporting that artesunate may have a positive effect on the treatment of COVID-19. Artesunate may be effective based on its effect on the anti-inflammatory activity, chloroquine-like endocytosis inhibition mechanism, and nuclear factor kappa B (NF-κB) signal pathway. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may cause neurological complications in addition to targeting the respiratory system. In this study, we have discussed the possible neuroprotective action mechanisms of artesunate. We think that systemic and intranasal topical artesunate administration may have a positive effect on neurological complications resulting from COVID-19.

Propofol reduces renal ischemia/reperfusion-induced acute lung injury by stimulating sirtuin 1 and inhibiting pyroptosis

The activation of pyroptosis is an important feature of renal ischemia/reperfusion (rI/R)-induced acute lung injury (ALI). Propofol, a general anesthetic, is known to inhibit inflammation in I/R-induced ALI. We investigated whether propofol could suppress pyroptosis during rI/R-induced ALI by upregulating sirtuin 1 (SIRT1). We generated an in vivo model of rI/R-induced ALI by applying microvascular clamps to the renal pedicles of rats for 45 min. Pathological studies revealed that rI/R provoked substantial lung injury and inflammatory cell infiltration. The rI/R stimulus markedly activated pyroptotic proteins such as NLRP3, ASC, caspase 1, interleukin-1β and interleukin-18 in the lungs, but reduced the mRNA and protein levels of SIRT1. Propofol treatment greatly inhibited rI/R-induced lung injury and pyroptosis, whereas it elevated SIRT1 expression. Treatment with the selective SIRT1 inhibitor nicotinamide reversed the protective effects of propofol during rI/R-induced ALI. Analogous defensive properties of propofol were detected in vitro in rat alveolar macrophages incubated with serum from the rI/R rat model. These findings indicate that propofol attenuates rI/R-induced ALI by suppressing pyroptosis, possibly by upregulating SIRT1 in the lungs.

The interrupted cross-talk of inflammatory and oxidative stress trajectories signifies the effect of artesunate against hepatic ischemia/reperfusion-induced inflammasomopathy

The antimalarial drug artesunate (Art) has proven its beneficial effects against ischemia/reperfusion (I/R) injury in diverse organs, but its potential role against hepatic I/R is still obscure. This study, hence, examined whether treatment with Art alone or in combination with rapamycin (Rapa), an mTOR inhibitor, can ameliorate hepatic I/R injury via targeting the NLRP3 inflammasome signaling pathway. Rats were divided into hepatic sham- and I/R-operated rats. The latter were either left untreated (I/R group) or treated with Art, Rapa, or their combination. On the molecular level, all treatment regimens succeeded to hinder inflammasome assembly and activation, assessed as NLRP3, ASC, cleaved caspase-1, caspase-11, N-terminal cleaved gasdermin-D (GSDMD-N), IL-1β, and IL-18. This effect was associated by the inhibition in the harmful signaling pathways HMGB1/RAGE and TLR4/MyD88/TRAF6 to inactivate the transcription factor NF-κB and the production of its pro-inflammatory cytokines IL-1β, IL-18, IL-6, and TNF-α. Additionally, this effect entailed the inhibition of ICAM-1/MPO/ROS cascade, which in turn hampered cell demise induced by apoptosis, manifested as correction of the imbalanced Bcl2/Bax, as well as pyroptosis (LDH, cleaved caspase-1, caspase-11, GSDMD-N, IL-1β, and IL-18), and necrosis. The corrected pathways were reflected on the improved liver function (serum ALT, AST, and LDH) and microscopical hepatic architecture. Noteworthy, the effect of Art on all parameters exceeded significantly that of Rapa and even improved the effect of the latter in the combination group. In conclusion, our results suggest novel roles for Art in abating functional and structural I/R-induced hepatic abnormalities via several traversing cross-talking pathways that succeeded to abate NLRP3 inflammasome and cell death.

Nodakenin alleviates renal ischaemia-reperfusion injury via inhibiting reactive oxygen species-induced NLRP3 inflammasome activation

BACKGROUND

Acute kidney injury (AKI) is a vital contributor to chronic kidney disease and limited therapeutic options are existed to preserve the renal injury. The research presented here investigated the protective effect of nodakenin against AKI and the underlying mechanism.

METHODS

The effect of nodakenin was investigated in ischaemia reperfusion-induced renal injury (IRI) of AKI mice and hypoxia-treated primary renal tubular cells. Briefly, renal functions including creatinine and urea nitrogen were determined and mechanisms associated inflammation were investigated by the advantage of immunohistochemistry, western blot, RT-PCR and flow cytometry.

RESULTS

Deterioration of renal functions including and creatinine, urea nitrogen and tubular necrosis were observed in IRI-AKI model. In contrast, nodakenin strikingly alleviated the deterioration of creatinine, urea nitrogen and tubular necrosis when compared with IRI model. Moreover, nodakenin could significantly inhibit the expression of pro-inflammatory cytokines including interleukin (IL)-1β, IL-6 and tumour necrosis factor-α both in hypoxia-treated primary renal tubular cells and in AKI model. Mechanistic studies revealed that nodakenin dramatically suppressed the production of reactive oxygen species and subsequent NLPR3 inflammasome activation.

CONCLUSION

In summary, these findings provided a solid evidence base and a new drug option for the treatment of AKI.

Dexmedetomidine ameliorates renal ischemia reperfusion-mediated activation of the NLRP3 inflammasome in alveolar macrophages

Renal ischemia-reperfusion (rI/R) is a risk factor for acute lung injury (ALI). Alveolar macrophages (AMs) activation mediated by rI/R-induced ALI is one of the pathogeneses associated with the development of ALI. In rI/R, α₂-adrenergic receptor agonists have been indicated to be effective in decreasing urea nitrogen concentrations. In this study, we explored the underlying pathogenesis of the clinically obtainable α₂-adrenergic receptor agonist dexmedetomidine (DEX) in protecting against rI/R -mediated AMs activation. We incubated AMs with the serum of sham and rI/R rats in the presence or absence of various concentrations of DEX. We used an enzyme-linked immunosorbent assay to detect the secretion levels of GSH, LDH, IL-18, IL-1β, and HMGB1 in the culture supernatant. We employed real-time polymerase chain reaction to assess the expression of NOX-4 mRNA, and western blotting to observe the protein levels of NOX-4, the NLRP3 inflammasome, AMPK, and eNOS. In addition, we used immunofluorescence to analyze ROS and MMP activity. Incubation of AMs with DEX suppressed rI/R-mediated cellular LDH production and ROS release. DEX also abolished the rI/R-mediated decrease in the activity of GSH and increased the levels of the rI/R-related NADPH oxidase protein NOX-4. Furthermore, DEX reduced the amelioration of the mitochondrial potential induced by rI/R. Our study showed that DEX inhibits rI/R-mediated levels of the NLRP3 inflammasome proteins ASC, NLRP3, HMGB1 and p20, and ameliorates rI/R-mediated AMPK signaling inactivation. Therefore, DEX reduces the levels of two mediators that are activated by the NLRP3 inflammasome: IL-18 and IL-1β. Finally, our study established that DEX mitigates the rI/R-mediated decrease in eNOS, demonstrating its protective functions against AMs activation. In conclusion, our study demonstrated that the protective action of DEX in AMs is induced through amelioration of HMGB1-NLRP3 inflammasome-AMPK signaling. Our results suggest that the anesthetic reagent DEX exerts beneficial effects to ameliorate rI/R-induced ALI.

Penehyclidine hydrochloride inhibits renal ischemia/reperfusion-induced acute lung injury by activating the Nrf2 pathway

The nuclear factor (NF)-κB and NOD-like receptor protein 3 (NLRP3) pathways promote inflammatory signaling that injures the kidneys, whereas the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway promotes anti-inflammatory signaling that inhibits oxidative damage. Penehyclidine hydrochloride (PHC) inhibits NF-κB and activates Nrf2 signaling. We investigated whether PHC induces communication between the Nrf2 and NF-κB/NLRP3 pathways, thereby protecting against renal ischemia/reperfusion (rI/R)-induced lung inflammation. Rat alveolar macrophages (NR8383 cells) were stimulated for 24 h with PHC with or without brusatol (a Nrf2 antagonist), after which they were treated for 4 h with tert-butyl hydroperoxide (10 mM). PHC Nrf2-dependently alleviated tert-butyl hydroperoxide-induced reactive oxygen species production in alveolar macrophages. Additionally, wild-type and Nrf2^-/- rats were each divided into four groups: (1) sham, (2) PHC (1 mg/kg), (3) rI/R and (4) rI/R + PHC (1 mg/kg). PHC markedly induced the Nrf2 and adenosine monophosphate-activated protein kinase pathways and suppressed rI/R-induced NF-κB and NLRP3 activation in the lungs. Nrf2 deficiency diminished the ability of PHC to ameliorate rI/R-induced histopathological alterations and reactive oxygen species release in the lungs; however, PHC inhibited NLRP3 signaling Nrf2-dependently, while it inhibited NF-κB signaling Nrf2-independently. Our findings demonstrate the beneficial effects of PHC on rI/R-induced lung inflammation.

Anti-malarial drug, artemisinin and its derivatives for the treatment of respiratory diseases

Artemisinins are sesquiterpene lactones with a peroxide moiety that are isolated from the herb Artemisia annua. It has been used for centuries for the treatment of fever and chills, and has been recently approved for the treatment of malaria due to its endoperoxidase properties. Progressively, research has found that artemisinins displayed multiple pharmacological actions against inflammation, viral infections, and cell and tumour proliferation, making it effective against diseases. Moreover, it has displayed a relatively safe toxicity profile. The use of artemisinins against different respiratory diseases has been investigated in lung cancer models and inflammatory-driven respiratory disorders. These studies revealed the ability of artemisinins in attenuating proliferation, inflammation, invasion, and metastasis, and in inducing apoptosis. Artemisinins can regulate the expression of pro-inflammatory cytokines, nuclear factor-kappa B (NF-κB), matrix metalloproteinases (MMPs), vascular endothelial growth factor (VEGF), promote cell cycle arrest, drive reactive oxygen species (ROS) production and induce Bak or Bax-dependent or independent apoptosis. In this review, we aim to provide a comprehensive update of the current knowledge of the effects of artemisinins in relation to respiratory diseases to identify gaps that need to be filled in the course of repurposing artemisinins for the treatment of respiratory diseases. In addition, we postulate whether artemisinins can also be repurposed for the treatment of COVID-19 given its anti-viral and anti-inflammatory properties.

Pharmacological Inhibition of HDAC6 Attenuates NLRP3 Inflammatory Response and Protects Dopaminergic Neurons in Experimental Models of Parkinson's Disease

Aim

To investigate the role of histone deacetylase 6 (HDAC6) deacetylation activity in nucleotide-binding oligomerization domain and leucine-rich repeat pyrin 3 domain (NLRP3) inflammatory response and explore the effects of pharmacological inhibition of HDAC6 with tubastatin A (TBA) on dopaminergic injury.

Methods

Using 6-OHDA-induced Parkinson's disease (PD) models, we examined the effects of TBA on NLRP3 activation and cell injury in SH-SY5Y cells. We also investigated the effects of TBA on NLRP3 inflammatory responses and dopaminergic injury in the nigrostriatal system in mice and analyzed the acetylation levels of peroxiredoxin2 (Prx2) and oxidative stress.

Results

TBA inhibited 6-OHDA-induced NLRP3 activation, as demonstrated by decreased expressions of NLRP3 and matured caspase-1 and IL-1β, and also alleviated glial proliferation and dopaminergic neuronal degeneration. Notably, TBA recovered acetylation levels of Prx2 and reduced oxidative stress.

Conclusion

Our findings indicate that pharmacological inhibition of HDAC6 with TBA attenuates NLRP3 inflammation and protects dopaminergic neurons, probably through Prx2 acetylation. This study suggests that the deacetylase catalytic domain of HDAC6 is a potential target for PD treatment.

Propofol post-conditioning lessens renal ischemia/reperfusion-induced acute lung injury associated with autophagy and apoptosis through MAPK signals in rats

Renal Ischemia/Reperfusion (rI/R)-induced acute lung injury (ALI) is a major problem in rI/R. The objective of the current study was to explore the defensive roles of propofol (Pro), an intravenous anesthetic, on rI/R-induced ALI through mitogen-activated protein kinase (MAPK) signaling. Rats were divided into Sham, Pro (10 mg/kg), rI/R, rI/R + Pro (5 mg/kg), and rI/R + Pro (10 mg/kg) groups. Rats were treated with Pro at 1 h after rI/R treatment. Serum and lung tissues at 24 h after rI/R were collected to evaluate morphological changes and the expression of myeloperoxidase (MPO), inflammatory cytokines, and crucial proteins in the MAPK pathway. Pro attenuated the production of mediators, resulting in reduced levels of autophagy and apoptosis by restricting the MAPK pathway in rI/R-induced ALI model. Pro represses rI/R-induced pulmonary autophagy and apoptosis by decreasing the production of inflammatory molecules, and the effects of Pro are involved in the inhibition of the MAPK pathway.

Inhibition of PRMT5 Attenuates Oxidative Stress-Induced Pyroptosis via Activation of the Nrf2/HO-1 Signal Pathway in a Mouse Model of Renal Ischemia-Reperfusion Injury

Background

Extensive evidence has demonstrated that oxidative stress, pyroptosis, and proinflammatory programmed cell death are related to renal ischemia/reperfusion (I/R) injury. However, the underlying mechanism remains to be illustrated. Protein arginine methylation transferase 5 (PRMT5), which mediates arginine methylation involved in the regulation of epigenetics, exhibits a variety of biological functions and essential roles in diseases. The present study investigated the role of PRMT5 in oxidative stress and pyroptosis induced by I/R injury in a mouse model and in a hypoxia/reoxygenation (H/R) model of HK-2 cells.

Methods

C57 mice were used as an animal model. All mice underwent right nephrectomy, and the left renal pedicles were either clamped or not. Renal I/R injury was induced by ligating the left renal pedicle for 30 min followed by reperfusion for 24 h. HK-2 cells were exposed to normal conditions or stimulation through H/R. EPZ015666(EPZ)—a selective potent chemical inhibitor—and small interfering RNA (siRNA) were administered to suppress the function and expression of PRMT5. The levels of urea nitrogen and creatinine in the serum and renal tissue injury were assessed. Immunohistochemistry, western blotting, and reverse transcription-polymerase chain reaction were used to evaluate pyroptosis-related proteins including nod-like receptor protein-3, ASC, caspase-1, caspase-11, GSDMD-N, and interleukin-1β. Cell apoptosis and cell viability were detected through flow cytometry, and the levels of reactive oxygen species (ROS) and hydrogen peroxide (H₂O₂) were measured. Ki-67 was used to assess the proliferation of renal tubular epithelium. In addition, the activity of malondialdehyde and superoxide dismutase was determined.

Results

I/R or H/R induced an increase in the expression of PRMT5. Inhibition of PRMT5 by EPZ alleviated oxidative stress and I/R- or H/R-induced pyroptosis. In renal tissue, the application of EPZ promoted the proliferation of tubular epithelium. In addition, H/R-induced pyroptosis in HK-2 cells was dependent on oxidative stress in vitro. Administration of either EPZ or siRNA led to decreased expression of pyroptosis-related proteins. Inhibition of PRMT5 also attenuated the I/R- or H/R-induced oxidative stress in vivo and in HK-2 cells, respectively. It also resulted in a distinct decrease in the levels of malondialdehyde and H₂O₂, and an apparent increase in superoxide dismutase activity in mouse renal tissue. Moreover, it led to a significant decrease in the levels of ROS and H₂O₂ in HK-2 cells. When activated, NF-E2-related factor/heme oxygenase-1 (Nrf2/HO-1)—a key regulator of various cytoprotective proteins that withstand oxidative damage—can decrease the generation of ROS. Nrf2/HO-1 was downregulated during I/R in tissues and H/R in HK-2 cells, and this effect was reversed by the PRMT5 inhibitor. Furthermore, the expressions of Nrf2 and HO-1 proteins were markedly upregulated by EPZ or siRNA against PRMT5.

Conclusion

PRMT5 is involved in ischemia- and hypoxia-induced oxidative stress and pyroptosis in vitro and in vivo. Inhibition of PRMT5 may ameliorate renal I/R injury by suppressing oxidative stress and pyroptosis via the activation of the Nrf2/HO-1 pathway, as well as promoting the proliferation of tubular epithelium. Therefore, PRMT5 may be a promising therapeutic target.

Dihydroartemisinin attenuates lipopolysaccharide‑induced acute lung injury in mice by suppressing NF‑κB signaling in an Nrf2‑dependent manner

Acute lung injury (ALI) is a severe health issue with significant morbidity and mortality. Artemisinin is used for the treatment of fever and malaria in clinical practice. Dihydroartemisinin (DHA), the major active metabolite of artemisinin, plays a role in anti‑organizational fibrosis and anti‑neuronal cell death. However, whether DHA can attenuate ALI remains unclear. The current study thus examined the effects of DHA on ALI and primary macrophages. The results revealed that DHA attenuated lipopolysaccharide (LPS)‑induced pulmonary pathological damage. DHA suppressed the LPS‑induced infiltration of inflammatory cells, the elevation of myeloperoxidase activity, oxidative stress and the production of pro‑inflammatory cytokines, including interleukin (IL)‑1β, tumor necrosis factor‑α, and IL‑6. Furthermore, DHA reduced the LPS‑induced inflammatory response by suppressing the degradation of I‑κB and the nuclear translocation of nuclear factor κ‑light‑chain‑enhancer of activated B cells (NF‑κB)/p65 in vivo and in vitro. DHA activated the nuclear factor‑erythroid 2 related factor 2 (Nrf2) pathway, which was suppressed by LPS treatment. The Nrf2 inhibitor, ML385, diminished the protective effects of DHA against LPS‑induced inflammation in macrophages. On the whole, the findings of this study demonstrate that DHA exerts therapeutic effects against LPS‑induced ALI by inhibiting the Nrf2‑mediated NF‑κB activation in macrophages. The present study also confirmed the therapeutic effects of DHA in mice with LPS‑induced ALI. Thus, these findings demonstrate that DHA exhibits anti‑inflammatory activities and may be a therapeutic candidate for the treatment of ALI.

Penehyclidine hydrochloride defends against LPS-induced ALI in rats by mitigating endoplasmic reticulum stress and promoting the Hes1/Notch1 pathway

Penehyclidine hydrochloride (PHC) is a novel anticholinergic drug applied broadly in surgeries as a preanesthetic medication. A substantial amount of research indicates that PHC has lung defensive properties. Considering that endoplasmic reticulum (ER) stress exerts a crucial function in cell apoptosis associated with the lipopolysaccharides (LPS)-induced acute lung injury (ALI) model, we aimed to determine whether regulation of ER stress in the LPS-induced ALI model was associated with the lung defensive role of PHC. Adult male SD rats were administered LPS (5 mg/kg, intratracheally) followed by PHC (1.0 mg/kg, intravenously) for 24 h. The NR8383 alveolar macrophages were randomly separated into Sham, LPS (100 ng/mL), and PHC (1, 2.5, or 5 μg/mL) + LPS groups. PHC (1, 2.5, or 5 μg/mL) + LPS groups were treated with PHC alone for 1 h after LPS exposure. Posttreatment with PHC relieved LPS-induced pulmonary impairment and blocked LPS-mediated lung apoptosis, indicated by the downregulation of the lung apoptotic indicators malondialdehyde and superoxide dismutase in serum at 24 h after LPS-induced ALI. PHC (1-5 μg/mL) did not influence the activity of cultivated NR8383 alveolar macrophages in vitro. However, postconditioning with PHC dosage-dependently reduced LPS-mediated cell apoptosis. Additionally, many studies have indicated that PHC administration inhibits ER stress and initiates hairy and enhancer of split 1 (Hes1)/(Notch1) signaling by decreasing phosphorylated α subunit of eukaryotic initiation factor 2α (p-eIF2α)/eukaryotic translation initiation factor 2α (eIF2α) and Phospho-protein kinase R-like ER kinase (p-PERK)/ protein kinase R-like ER kinase (PERK) proportions; inhibiting C/EBP-homologous protein (CHOP), activating transcription factor 4 (ATF4), caspase-3, and Bcl2-associated x (Bax) activity; and enhancing notch1 intracellular domain (NICD), Notch1, B-cell lymphoma-2 (Bcl-2), and Hes1 activity in vivo and in vitro. In addition, the defensive functions of PHC on LPS-activated NR8383 alveolar macrophages were abrogated through the Notch1 pathway antagonist [(3,5-difluorophenacetyl)-1-alanyl] -phenylglycine-butyl ester (DAPT). In conclusion, PHC alleviates LPS-induced ALI by ameliorating ER stress-mediated apoptosis and promoting Hes1/Notch1 signaling in vivo and in vitro.

The Defensive Action of LYRM03 on LPS-Induced Acute Lung Injury by NF-κB/TLR4/NLRP3 Signals

The aim of the current investigation was to study the role of 3-amino-2-hydroxy-4-phenyl-valyl-isoleucine (LYRM03) in lipopolysaccharide (LPS)-induced acute lung injury (ALI) and investigate its potential pathogenesis. An LPS-induced ALI model was produced with LPS (5 mg/kg) followed by 24 h of injury. Rats were randomly assigned to 6 groups for in vivo experiments: (1) Sham, (2) LYRM03 (20 mg/kg), (3) LPS, (4) LPS plus LYRM03 (5 mg/kg), (5) LPS plus LYRM03 (10 mg/kg), and (6) LPS plus LYRM03 (20 mg/kg). The rat alveolar macrophage cell line (NR8383) cells were divided into 6 groups for in vitro experiments: (1) Sham, (2) LYRM03 (200 μmol/L), (3) LPS (100 ng/mL), (4) LPS plus LYRM03 (50 μmol/L), (5) LPS plus LYRM03 (100 μmol/L), and (6) LPS plus LYRM03 (200 μmol/L). Further study about siRNA targeting NF-κB p65, TLR4, and NLRP3 to explore the potential mechanism of LYRM03 in the LPS-induced ALI models have been done. Therefore, LYRM03 decreased LPS-induced ALI and NR8383 activation as demonstrated through hematoxylin-eosin staining and western blot analysis in vivo and in vitro. LYRM03 ameliorated the content of protein in bronchoalveolar lavage fluid, myeloperoxidase in the lung and malondialdehyde (MDA) in serum. In addition, LYRM03 ameliorated the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-18 (IL-18) in the serum of rats and the supernatant of NR8383 cells. Moreover, LYRM03 significantly inhibited the activities of nuclear factor kappa B (NF-κB), myeloid differentiation factor 88 (MyD88), and toll-like receptor 4 (TLR4). LYRM03 also reduced the increase in the inflammasome, including apoptosis-related speck-like protein containing CARD (ASC), and NOD-like receptor 3 (NLRP3), in LPS-stimulated rats and NR8383 cells. The extent of injury and lung injury scores in the LYRM03 (20 mg/kg) + siRNA targeting NF-κB p65, TLR4, or NLRP3 + LPS-treated rats were higher than that in the LYRM03 (20 mg/kg) + LPS-treated rats. In summary, LYRM03 conferred an intensely lung defensive action on LPS-induced ALI in vivo and in vitro, which could be associated with the abatement of TLR4-induced NLRP3/NF-κB.

Reactive species-induced microvascular dysfunction in ischemia/reperfusion

Vascular endothelial cells line the inner surface of the entire cardiovascular system as a single layer and are involved in an impressive array of functions, ranging from the regulation of vascular tone in resistance arteries and arterioles, modulation of microvascular barrier function in capillaries and postcapillary venules, and control of proinflammatory and prothrombotic processes, which occur in all segments of the vascular tree but can be especially prominent in postcapillary venules. When tissues are subjected to ischemia/reperfusion (I/R), the endothelium of resistance arteries and arterioles, capillaries, and postcapillary venules become dysfunctional, resulting in impaired endothelium-dependent vasodilator and enhanced endothelium-dependent vasoconstrictor responses along with increased vulnerability to thrombus formation, enhanced fluid filtration and protein extravasation, and increased blood-to-interstitium trafficking of leukocytes in these functionally distinct segments of the microcirculation. The number of capillaries open to flow upon reperfusion also declines as a result of I/R, which impairs nutritive perfusion. All of these pathologic microvascular events involve the formation of reactive species (RS) derived from molecular oxygen and/or nitric oxide. In addition to these effects, I/R-induced RS activate NLRP3 inflammasomes, alter connexin/pannexin signaling, provoke mitochondrial fission, and cause release of microvesicles in endothelial cells, resulting in deranged function in arterioles, capillaries, and venules. It is now apparent that this microvascular dysfunction is an important determinant of the severity of injury sustained by parenchymal cells in ischemic tissues, as well as being predictive of clinical outcome after reperfusion therapy. On the other hand, RS production at signaling levels promotes ischemic angiogenesis, mediates flow-induced dilation in patients with coronary artery disease, and instigates the activation of cell survival programs by conditioning stimuli that render tissues resistant to the deleterious effects of prolonged I/R. These topics will be reviewed in this article.

Transient receptor potential vanilloid 4 is a critical mediator in LPS mediated inflammation by mediating calcineurin/NFATc3 signaling

Transient Receptor Potential Vanilloid 4 (TRPV4) ion channel is thought to be an essential component of inflammatory response. However, its role and mechanism in regulating acute lung injury (ALI) and macrophages activation are not well characterized. In our study, we observe that blockade of TRPV4 using GSK2193874 or HC-067047 greatly improve the pneumonedema, the lung pathologic changes, the up-regulation of proinflammatory cytokines and the neutrophil infiltration in LPS-induced lung injury. In vitro, knockdown of TRPV4 in macrophages reduces the levels of pro-inflammatory cytokines, ROS production, Ca²⁺ concentration in cytoplasma and the activation of calcineurin/NFATc3 signaling. Importantly, change of extracellular Ca²⁺ in culture medium prevents LPS-induced NFATc3 nuclear translocation, up-regulation of proinflammatory cytokines and ROS production in macrophages. Inhibition of calcineurin with cyclosporine A, FK506 down-regulates the levels of NFATc3 nuclear translocation and proinflammatory cytokines expression. Our results demonstrate that TRPV4-dependent Ca²⁺ influx contributes to LPS-induced macrophage activation by calcineurin-NFATc3 pathway.

Erythropoietin Ameliorates Lung Injury by Accelerating Pulmonary Endothelium Cell Proliferation via Janus Kinase-Signal Transducer and Activator of Transcription 3 Pathway After Kidney Ischemia and Reperfusion Injury

BACKGROUND/AIMS

Kidney ischemia and reperfusion injury could cause microvascular barrier dysfunction, lung inflammatory cascades activation, and programmed cell death of pulmonary endothelium, leading to acute lung injury. Our study aimed at determining whether erythropoietin (EPO) can ameliorate lung dysfunction following renal ischemia and reperfusion (IR) injury and explored the underlying mechanisms.

METHODS

In vivo, C57BL/6 mice received EPO (6000 U/kg) before right renal vascular pedicles clamping for 30 minutes, followed by 24 hours of reperfusion. The lung histopathologic changes and inflammatory cytokines expression were assessed. In vitro, cultured human umbilical vein endothelial cells were treated with EPO, and apoptosis rate, proliferation capacity, and phosphorylation status of the Janus kinase-signal transducer and activator of transcription 3 (Jak-STAT3) pathway were measured respectively in the presence or absence of lipopolysaccharide stimulation.

RESULTS

In vivo, EPO remarkably attenuated pulmonary interstitial and alveolar epithelial edema caused by renal IR injury. In vitro, the proliferation capacity of human umbilical vein endothelial cells was significantly increased under EPO stimulation, which correlated with changes in Jak-STAT3 signaling.

CONCLUSION

Our data indicated that EPO is able to ameliorate acute lung tissue damage induced by renal IR, and at least in part, via the Jak-STAT3 pathway.

The Nox1/Nox4 inhibitor attenuates acute lung injury induced by ischemia-reperfusion in mice

Lung ischemia and reperfusion injury (LIRI) were mediated by several processes including over-production of reactive oxygen species (ROS) and inflammatory activation. ROS generated by nicotinamide adenine dinucletide phosphate (NADPH) oxidase (Nox) may play a pivotal role in pathophysiological changes in a range of disease. However, it was poorly understood in LIRI. Thus, the purpose of our study was to explore whether GKT137831, as a special dual inhibitor of Nox1 and 4, could alleviate LIRI in mice model and explore the minimal dose. According to the protocol, this study was divided into two parts. The first part was to determine the minimal dose of Nox1/4 inhibitor in attenuating LIRI via histopathology and apoptosis analysis. Eighteen C57BL/6J male wild-type mice were randomly divided in to sham, 2.5Nox+sham, 5.0Nox+sham, IR, 2.5Nox+IR and 5.0Nox+IR groups. According to the different group, mice were pretreated with corresponding dose of Nox1/4 inhibitors or normal saline. After LIRI, the results showed 5.0mg/kg Nox1/4 inhibitor could be considered as the minimal dose to alleviate injury by decreasing of lung injury score and the number of TUNEL-positive cells. The second part was to further verify the benefit of 5.0mg/kg Nox1/4 inhibitor in lung protective effects. Thirty-seven C57BL/6J male wild-type mice were divided in to sham, IR and 5.0Nox+IR groups randomly. The results showed that expressions of inflammatory, autophagy cytokines were markedly elevated and PH value was declined after LIRI. However, 5.0 mg/kg Nox1/4 inhibitor significantly attenuated cytokine production as reflected by immunohistochemistry, western blotting and Q-PCR analysis. In conclusion, our findings suggested that 5.0mg/kg Nox1/4 inhibitor contributed to protect lung tissue damage after LIRI via the suppression of inflammatory and autophagy activation.

Chick Embryo: A Preclinical Model for Understanding Ischemia-Reperfusion Mechanism

Ischemia-reperfusion (I/R)-related disorders, such as stroke, myocardial infarction, and peripheral vascular disease, are among the most frequent causes of disease and death. Tissue injury or death may result from the initial ischemic insult, primarily determined by the magnitude and duration of the interruption in blood supply and then by the subsequent reperfusion-induced damage. Various in vitro and in vivo models are currently available to study I/R mechanism in the brain and other tissues. However, thus far, no in ovo I/R model has been reported for understanding the I/R mechanisms and for faster drug screening. Here, we developed an in ovo Hook model of I/R by occluding and releasing the right vitelline artery of a chick embryo at 72 h of development. To validate the model and elucidate various underlying survival and death mechanisms, we employed imaging (Doppler blood flow imaging), biochemical, and blotting techniques and evaluated the cell death mechanism: autophagy and inflammation caused by I/R. In conclusion, the present model is useful in parallel with established in vitro and in vivo I/R models to understand the mechanisms of I/R development and its treatment.