Histone deacetylases: potential therapeutic targets for idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive disease of unknown origin and the most common interstitial lung disease. However, therapeutic options for IPF are limited, and novel therapies are urgently needed. Histone deacetylases (HDACs) are enzymes that participate in balancing histone acetylation activity for chromatin remodeling and gene transcription regulation. Increasing evidence suggests that the HDAC family is linked to the development and progression of chronic fibrotic diseases, including IPF. This review aims to summarize available information on HDACs and related inhibitors and their potential applications in treating IPF. In the future, HDACs may serve as novel targets, which can aid in understanding the etiology of PF, and selective inhibition of single HDACs or disruption of HDAC genes may serve as a strategy for treating PF.

Pt(IV) complexes loaded hollow copper sulfide nanoparticles for tumor chemo/photothermal/photodynamic therapy.

Hollow CuS nanoparticles can achieve photothermal and photodynamic therapy (PDT) in tumor treatment. However, excessive GSH in the tumor cells will consume the reactive oxygen species produced by PDT and reduce the PDT effect. Cisplatin is a broad-spectrum antineoplastic drug that can be used in a variety of tumor treatments. However, cisplatin is cytotoxic to normal cells while it kills tumor cells. Therefore, we construct Pt(IV) complexes loaded hollow CuS nanoparticles to attenuate the toxicity of cisplatin and enhance the PDT effect of the hollow CuS nanoparticles. The nanoparticles were proved to be able to accumulate around the tumor site through the enhanced permeability and retention (EPR) effect to achieve a synergistic chemo/photothermal/photodynamic therapy.

NBR1-p62-Nrf2 mediates the anti-pulmonary fibrosis effects of protodioscin.

BACKGROUND: Idiopathic pulmonary fibrosis is a persistent disease of the lung interstitium for which there is no efficacious pharmacological therapy. Protodioscin, a steroidal saponin, possesses diverse pharmacological properties; however, its function in pulmonary fibrosis is yet to be established. Hence, in this investigation, it was attempted to figure out the anti-pulmonary fibrosis influences of protodioscin and its pharmacological properties related to oxidative stress. METHODS: A mouse lung fibrosis model was generated using tracheal injections of bleomycin, followed by intraperitoneal injection of different concentrations of protodioscin, and the levels of oxidative stress and fibrosis were detected in the lungs. Multiple fibroblasts were treated with TGF-ß to induce their transition to myofibroblasts. It was attempted to quantify myofibroblast markers' expression levels and reactive oxygen species levels as well as Nrf2 activation after co-incubation of TGF-ß with fibroblasts and different concentrations of protodioscin. The influence of protodioscin on the expression and phosphorylation of p62, which is associated with Nrf2 activation, were detected, and p62 related genes were predicted by STRING database. The effects of Nrf2 inhibitor or silencing of the Nrf2, p62 and NBR1 genes, respectively, on the activation of Nrf2 by protodioscin were examined. The associations between p62, NBR1, and Keap1 in the activation of Nrf2 by protodioscin was demonstrated using a co-IP assay. Nrf2 inhibitor were used when protodioscin was treated in mice with pulmonary fibrosis and lung tissue fibrosis and oxidative stress levels were detected. RESULTS: In vivo, protodioscin decreased the levels of fibrosis markers and oxidative stress markers and activated Nrf2 in mice with pulmonary fibrosis, and these effects were inhibited by Nrf2 inhibitor. In vitro, protodioscin decreased the levels of myofibroblast markers and oxidative stress markers during myofibroblast transition and promoted Nrf2 downstream gene expression, with reversal of these effects after Nrf2, p62 and NBR1 genes were silenced or Nrf2 inhibitors were used, respectively. Protodioscin promoted the binding of NBR1 to p62 and Keap1, thereby reducing Keap1-Nrf2 binding. CONCLUSION: The NBR1-p62-Nrf2 axis is targeted by protodioscin to reduce oxidative stress and inhibit pulmonary fibrosis.

Sulfasalazine ameliorates lipopolysaccharide-induced acute lung injury by inhibiting oxidative stress and nuclear factor-kappaB pathways.

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) has a high mortality rate and incidence of complications. The pathophysiology of ALI/ARDS is still not fully understood. The lipopolysaccharide (LPS)-induced mouse model of ALI has been widely used to study human ALI/ARDS. Sulfasalazine (SASP) has antibacterial and anti-inflammatory effects and is used for treating inflammatory bowel and rheumatic diseases. However, the effect of SASP on LPS-induced ALI in mice has not yet been reported. Therefore, we aimed to investigate the effect of SASP on LPS-induced ALI in mice. Mice were intraperitoneally injected with SASP 2 h before or 4 h after LPS modeling. Pulmonary pathological damage was measured based on inflammatory factor expression (malondialdehyde and superoxide dismutase levels) in the lung tissue homogenate and alveolar lavage fluid. The production of inflammatory cytokines and occurrence of oxidative stress in the lungs induced by LPS were significantly mitigated after the prophylactic and long-term therapeutic administration of SASP, which ameliorated ALI caused by LPS. SASP reduced both the production of inflammatory cytokines and occurrence of oxidative stress in RAW264.7 cells, which respond to LPS. Moreover, its mechanism contributed to the suppression of NF-κB and nuclear translocation. In summary, SASP treatment ameliorates LPS-induced ALI by mediating anti-inflammatory and antioxidant effects, which may be attributed to the inhibition of NF-κB activation and promotion of antioxidant defenses. Thus, SASP may be a promising pharmacologic agent for ALI therapy.

NMDAR activation attenuates the protective effect of BM-MSCs on bleomycin-induced ALI via the COX-2/PGE2 pathway.

N-methyl-d-aspartate (NMDA) receptor (NMDAR) activation mediates glutamate (Glu) toxicity and involves bleomycin (BLM)-induced acute lung injury (ALI). We have reported that bone marrow-derived mesenchymal stem cells (BM-MSCs) are NMDAR-regulated target cells, and NMDAR activation inhibits the protective effect of BM-MSCs on BLM-induced pulmonary fibrosis, but its effect on ALI remains unknown. Here, we found that Glu release was significantly elevated in plasma of mice at d 7 after intratracheally injected with BLM. BM-MSCs were pretreated with NMDA (the selective agonist of NMDAR) and transplanted into the recipient mice after the BLM challenge. BM-MSCs administration significantly alleviated the pathological changes, inflammatory response, myeloperoxidase activity, and malondialdehyde content in the damaged lungs, but NMDA-pretreated BM-MSCs did not ameliorate BLM-induced lung injury in vivo. Moreover, NMDA down-regulated prostaglandin E2 (PGE2) secretion and cyclooxygenase (COX)-2 expression instead of COX-1 expression in BM-MSCs in vitro. We also found that NMDAR1 expression was increased and COX-2 expression was decreased, but COX-1 expression was not changed in primary BM-MSCs of BLM-induced ALI mice. Further, the cultured supernatants of lipopolysaccharide (LPS)-pretreated RAW264.7 macrophages were collected to detect inflammatory factors after co-culture with NMDA-pretreated BM-MSCs. The co-culture experiments showed that NMDA precondition inhibited the anti-inflammatory effect of BM-MSCs on LPS-induced macrophage inflammation, and PGE2 could partially alleviate this inhibition. Our findings suggest that NMDAR activation attenuated the protective effect of BM-MSCs on BLM-induced ALI in vivo. NMDAR activation inhibited COX-2 expression and PGE2 secretion in BM-MSCs and weakened the anti-inflammatory effect of BM-MSCs on LPS-induced macrophage inflammation in vitro. In conclusion, NMDAR activation attenuates the protective effect of BM-MSCs on BLM-induced ALI via the COX-2/PGE2 pathway. Keywords: Acute Lung Injury, BM-MSCs, NMDA receptor, COX-1/2, PGE2.

Asarinin attenuates bleomycin-induced pulmonary fibrosis by activating PPARγ.

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease that lacks effective treatment modalities. Once patients are diagnosed with IPF, their median survival is approximately 3-5 years. PPARγ is an important target for the prevention and treatment of pulmonary fibrosis. Asarinin is a lignan compound that can be extracted from food plant Asarum heterotropoides. In this study, we investigated the therapeutic effects of asarinin in a pulmonary fibrosis model constructed using bleomycin in mice and explored the underlying mechanisms. Intraperitoneal administration of asarinin to mice with pulmonary fibrosis showed that asarinin effectively attenuated pulmonary fibrosis, and this effect was significantly inhibited by the PPARγ inhibitor GW9662. Asarinin inhibited TGF-ß1-induced fibroblast-to-myofibroblast transition in vitro, while GW9662 and PPARγ gene silencing significantly inhibited this effect. In addition, asarinin inhibited not only the canonical Smad pathway of TGF-ß but also the non-canonical AKT and MAPK pathways by activating PPARγ. Our study demonstrates that asarinin can be used as a therapeutic agent for pulmonary fibrosis, and that PPARγ is its key target.

Sp1 mediated the inhibitory effect of glutamate on pulmonary surfactant synthesis.

BACKGROUND: Studies have shown that the release of endogenous glutamate (Glu) participates in lung injury by activating N-methyl-D-aspartate receptor (NMDAR), but the mechanism is still unclear. This study was to investigate the effects and related mechanisms of Glu on the lipid synthesis of pulmonary surfactant (PS) in isolated rat lung tissues. METHODS: The cultured lung tissues of adult SD rats were treated with Glu. The amount of [3H]-choline incorporation into phosphatidylcholine (PC) was detected. RT-PCR and Western blot were used to detect the changes of mRNA and protein expression of cytidine triphosphate: phosphocholine cytidylyltransferase alpha (CCTα), a key regulatory enzyme in PC biosynthesis. Western blot was used to detect the expression of NMDAR1, which is a functional subunit of NMDAR. Specific protein 1 (Sp1) expression plasmids were used. After transfected with Sp1 expression plasmids, the mRNA and protein levels of CCTα were detected by RT-PCR and Western blot in A549 cells. After treated with NMDA and MK-801, the mRNA and protein levels of Sp1 were detected by RT-PCR and Western blot in A549 cells. RESULTS: Glu decreased the incorporation of [3H]-choline into PC in a concentration- and time- dependent manner. Glu treatment significantly reduced the mRNA and protein levels of CCTα in lungs. Glu treatment up-regulated NMDAR1 protein expression, and the NMDAR blocker MK-801 could partially reverse the reduction of [3H]-choline incorporation induced by Glu (10-4 mol/L) in lungs. After transfected with Sp1 plasmid for 30 h, the mRNA and protein expression levels of CCTα were increased and the protein expression of Sp1 was also up-regulated. After A549 cells were treated with NMDA, the level of Sp1 mRNA did not change significantly, but the expression of nucleus protein in Sp1 was significantly decreased, while the expression of cytoplasmic protein was significantly increased. However, MK-801could reverse these changes. CONCLUSIONS: Glu reduced the biosynthesis of the main lipid PC in PS and inhibited CCTα expression by activating NMDAR, which were mediated by the inhibition of the nuclear translocation of Sp1 and the promoter activity of CCTα. In conclusion, NMDAR-mediated Glu toxicity leading to impaired PS synthesis may be a potential pathogenesis of lung injury.

NMDA receptor activation induces damage of alveolar type II cells and lung fibrogenesis through ferroptosis.

Ferroptosis, a newly discovered type of regulated cell death, has been implicated in numerous human diseases. Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal interstitial lung disease with poor prognosis and limited treatment options. Emerging evidence has linked ferroptosis and glutamate-determined cell fate which is considered a new light on the etiology of pulmonary fibrosis. Here, we observed that N-methyl d-aspartate receptor (NMDAR) activation promoted cell damage and iron deposition in MLE-12 cells in a dose-, time-, and receptor-dependent manner. This mediated substantial Ca2+ influx, upregulated the expression levels of nNOS and IRP1, and affected intracellular iron homeostasis by regulating the expression of iron transport-related proteins (i.e., TFR1, DMT1, and FPN). Excessive iron load promoted the continuous accumulation of total intracellular and mitochondrial reactive oxygen species, which ultimately led to ferroptosis. NMDAR inhibition reduced lung injury and pulmonary fibrosis in bleomycin-induced mice. Bleomycin stimulation upregulated the expression of NMDAR1, nNOS, and IRP1 in mouse lung tissues, which ultimately led to iron deposition via regulation of the expression of various iron metabolism-related genes. NMDAR activation initiated the pulmonary fibrosis process by inducing iron deposition in lung tissues and ferroptosis of alveolar type II cells. Our data suggest that NMDAR activation regulates the expression of iron metabolism-related genes by promoting calcium influx, increasing nNOS and IRP1 expression, and increasing iron deposition by affecting cellular iron homeostasis, ultimately leading to mitochondrial damage, mitochondrial dysfunction, and ferroptosis. NMDAR activation-induced ferroptosis of alveolar type II cells might be a key event to the initiation of pulmonary fibrosis.

Integration of Theory and Practice in Medical Morphology Curriculum in Postgraduate Training: A Flipped Classroom and Case-based Learning Exercise.

OBJECTIVE: The integration of training in theory and practice across the medical education spectrum is being encouraged to increase student understanding and skills in the sciences. This study aimed to determine the deciding factors that drive students' perceived advantages in class to improve precision education and the teaching model. METHODS: A mixed strategy of an existing flipped classroom (FC) and a case-based learning (CBL) model was conducted in a medical morphology curriculum for 575 postgraduate students. The subjective learning evaluation of the individuals (learning time, engagement, study interest and concentration, and professional integration) was collected and analyzed after FC-CBL model learning. RESULTS: The results from the general evaluation showed promising results of the medical morphology in the FC-CBL model. Students felt more engaged by instructors in person and benefited in terms of time-saving, flexible arrangements, and professional improvement. Our study contributed to the FC-CBL model in Research Design in postgraduate training in 4 categories: 1) advancing a guideline of precision teaching according to individual characteristics; 2) revealing whether a learning background is needed for a Research Design course to guide setting up a preliminary course; 3) understanding the perceived advantages and their interfaces; and 4) barriers and/or improvement to implement the FC-CBL model in the Research Design class, such as a richer description of e-learning and hands-on practice. CONCLUSION: Undertaking a FC-CBL combined model could be a useful addition to pedagogy for medical morphology learning in postgraduate training.

N-methyl-D-aspartate receptor blockers attenuate bleomycin-induced pulmonary fibrosis by inhibiting endogenous mesenchymal stem cells senescence.

Background: A large number of our previous studies showed that endogenous glutamate and N-methyl-D-aspartate receptor (NMDAR) activation may be involved in various types of acute lung injury, airway inflammation, asthma, and pulmonary fibrosis. In animal models, the transplantation of exogenous bone marrow mesenchymal stem cells (BM-MSCs) is the most promising treatment for idiopathic pulmonary fibrosis. However, there are limited reports on the status of endogenous BM-MSCs in the process of bleomycin-induced pulmonary fibrosis in animals. Methods: We constructed a mouse model of bleomycin-induced pulmonary fibrosis. In vitro, the senescence model of BM-MSCs was constructed with hydrogen peroxide and high concentration of N-methyl-D-aspartate (NDMA). The changes in aging-related indexes were detected by senescence associated beta-galactosidase (SA-ß-gal) staining, western blot, flow cytometry and real time-PCR. The epithelial-mesenchymal transformation (EMT) changes of mouse lung epithelial cells (MLE-12) co-cultured with senescent BM-MSCs were detected by immunofluorescence and western blotting. Results: We observed that endogenous BM-MSCs senescence occurs during bleomycin-induced pulmonary fibrosis in mice, and the model group had a higher expression level of the NMDAR subunit than the control group. We observed a significant increase in NMDAR subunit expression in a hydrogen peroxide-induced senescent cell model in vitro. BM-MSCs showed senescence-related phenotype and cell cycle arrest after high concentration of NMDA treatment. At the same time, the expression levels of the classic Wingless and int-1 (Wnt) pathway protein ß-cantenin and downstream cyclin D1 also changed. In the co-culture of aged BM-MSCs and MLE-12 cells, EMT can be promoted in MLE-12 cells, and MK-801 can partially antagonize the occurrence of EMT. The NMDAR antagonist can partially prevent the above phenomenon. Conclusions: High concentrations of NMDA can promote senescence of BM-MSCs. NMDAR blockers may inhibit endogenous BM-MSCs aging through the WNT signaling pathway, thereby reducing the effect of bleomycin-induced pulmonary fibrosis.

Activation of N-methyl-D-aspartate receptor regulates insulin sensitivity and lipid metabolism.

RATIONALE: Although significant progress has been made in understanding the mechanisms of steatosis and insulin resistance, the physiological functions of regulators in these processes remain largely elusive. Evidence has suggested that the glutamate/N-methyl-D-aspartic acid receptor (NMDAR) axis contributes to acute lung injury, pulmonary arterial hypertension, and diabetes, but the specific metabolic contribution of the glutamate/NMDAR axis is not clear. Here we provide data at the animal, cellular, and molecular levels to support the role of the glutamate/NMDAR axis as a therapeutic target for metabolic syndrome in obesity. Methods: We examined the glutamate level in the obese mouse induced by a high-fat diet (HFD) for 12 weeks. To assess the role of NMDAR in insulin sensitivity and lipid metabolism, we tested the effects of Memantine (an NMDAR antagonist) and NMDA (an NMDAR agonist) on mice fed with HFD or standard chow diet. The in vitros NMDAR roles were analyzed in hepatocytes and potential mechanisms involved in regulating lipid metabolism were investigated. Results: Glutamate was increased in the serum of HFD-treated mice. The NMDAR blockade by Memantine decreased the susceptibility to insulin resistance and hepatic steatosis in obese mice. NMDA treatment for 6 months induced obesity in mice, characterized by hyperglycemia, hyperlipidemia, insulin resistance, and pathological changes in the liver. We provided in vitro evidence demonstrating that NMDAR activation facilitated metabolic syndrome in obesity through promoting lipid accumulation. NMDAR inhibition attenuated lipid accumulation induced by palmitic acid. Mechanistically, NMDAR activation impaired fatty acid oxidation by reducing PPARα phosphorylation and activity. The PPARα activity reduction induced by NMDAR activation was reversibly mediated by ERK1/2 signaling. Conclusion: These findings revealed that targeting NMDAR might be a promising therapeutic strategy for metabolic syndrome in obesity.

[The construction and application of online open courses in Chinese colleges and universities--Taking the physiology course at Central South University of China as an example].

Massive open online course (MOOC) is a new learning model, which integrates the progress of novel educational concepts and the breakthrough of information technology. MOOC uses new web-based tools and online-environments to deliver knowledge education and lecture classes in a new paradigm. In this paper, we firstly reviewed the achievements through four stages of the construction and development of online courses of physiology in China in the past 20 years. Then, taking the physiology MOOC at Central South University of China as an example, we introduced the specific practices and experiences to construct the online physiological open course, including the online open course-based offline and online flipped classroom teaching practice. Finally, we discussed several important issues during the construction and application of online open courses, aiming to provide practical information for other universities.

[The metabolic networks of ferroptosis and links to lung diseases].

Ferroptosis is a newly discovered non-apoptotic form of regulated cell death driven by iron-dependent lipid peroxidation. The present studies have shown that many metabolic processes and homeostasis are affected by ferroptosis. It is related to many lung diseases, including acute lung injury, chronic obstructive pulmonary disease and pulmonary fibrosis, etc. Currently, the research on ferroptosis is still in its infancy. Previous studies have confirmed that ferroptosis is regulated by a variety of genes, and the mechanism is complex, mainly involving iron homeostasis and lipid peroxidation metabolism. This review summarizes some regulation networks of metabolic processes associated with ferroptosis and discusses the roles of ferroptosis in the pathophysiological progression of many lung diseases. We expected to provide new ideas and references for the treatment of these diseases.

[Research progress of endogenous bone marrow-derived mesenchymal stem cells in pulmonary fibrosis].

Pulmonary fibrosis is a chronic, diffuse, interstitial lung disease involving the pulmonary interstitium, alveoli, and bronchioles caused by various causes. There is no effective treatment. Currently, exogenous bone marrow-derived mesenchymal stem cells (BM-MSCs) transplantation has attracted much attention as a new stem cell therapy in the treatment of pulmonary fibrosis. Less attention has been paid to the functional status of endogenous BM-MSCs during pulmonary fibrosis. Based on summary on the anti-pulmonary fibrosis effect of BM-MSCs and its mechanism, this review further discusses the abnormal changes of bone marrow function in animals with pulmonary fibrosis and the role of glutamate NMDA receptor overactivation in mediating the functional inhibition of endogenous BM-MSCs induced by pulmonary fibrosis. This will provide potential ideas for finding effective treatments for pulmonary fibrosis.

G-CSF Inhibits Pulmonary Fibrosis by Promoting BMSC Homing to the Lungs via SDF-1/CXCR4 Chemotaxis.

Bone marrow mesenchymal stem cells (BMSCs) have multi-lineage differentiation potential and play an important role in tissue repair. Studies have shown that BMSCs gather at the injured tissue site after granulocyte-colony stimulating factor (G-CSF) administration. In this study, we first investigated whether G-CSF could promote BMSC homing to damaged lung tissue induced by bleomycin (BLM) and then investigated whether SDF-1/CXCR4 chemotaxis might be involved in this process. Next, we further studied the potential inhibitory effect of G-CSF administration in mice with lung fibrosis induced by bleomycin. We examined both the antifibrotic effects of G-CSF in mice with bleomycin-induced pulmonary fibrosis in vivo and its effects on the proliferation, differentiation and chemotactic movement of cells in vitro. Flow cytometry, real-time PCR, transwell and Cell Counting Kit-8 (CCK-8) assays were used in this study. The results showed that both preventative and therapeutic G-CSF administration could significantly inhibit bleomycin-induced pulmonary fibrosis. G-CSF enhanced BMSC migration to lung tissues, but this effect could be alleviated by AMD3100, which blocked the SDF-1/CXCR4 axis. We also found that BMSCs could inhibit fibroblast proliferation and transdifferentiation into myofibroblasts through paracrine actions. In conclusion, G-CSF exerted antifibrotic effects in bleomycin-induced lung fibrosis, in part by promoting BMSC homing to injured lung tissues via SDF-1/CXCR4 chemotaxis.

Regulatory effects of Prohibitin 1 on proliferation and apoptosis of pulmonary arterial smooth muscle cells in monocrotaline-induced PAH rats.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a severe pulmonary vascular disease characterized by unbalanced proliferation and apoptosis of pulmonary arterial smooth muscle cells (PASMCs). Prohibitin 1 (PHB1) is known for its significant anti-proliferative activity. However, the role of PHB1 in PASMCs and PAH have not been elucidated. METHODS: Monocrotaline (MCT 60 mg/kg) was used to build a PAH model in SD rats. Right ventricular systolic pressure (RVSP) and right ventricle (RV) hypertrophy were measured. Morphology of pulmonary vessels was observed by Hematoxylin-Eosin (HE) staining. Expression of PHB1 in pulmonary arteries and PASMCs was determinated by immunoblot and immunofluorescence. Cell proliferation was detected by CCK8 and EDU when PASMCs were stimulated by PDGF-BB (20 ng/mL). Furthermore, siRNA for PHB1 and Akt inhibitor were conducted to investigate the mechanism behind the role of PHB1 and AKT signaling pathway in PASMCs proliferation and apoptosis. RESULTS: The protein expression of PHB1 in PAH rats lung tissue was significantly up-regulated accompanied by elevated RVSP and enhanced RV hypertrophy. Immunohistochemistry showed that PHB1 was mainly localized in the pulmonary vascular smooth muscle layer. PDGF-BB significantly up-regulated the expression of PHB1 in rat primary PASMCs in a time- and dose-dependent manner. After PHB1 knock down, PASMCs proliferation was significantly suppressed while apoptosis was significantly recovered. Meanwhile the level of proliferating cell nuclear antigen (PCNA) and P-Akt were significantly down-regulated. Perifosine (Akt inhibitor) also significantly inhibit proliferation of PASMCs. CONCLUSION: PHB1 contributes to pulmonary vascular remodeling by accelerating proliferation of PASMCs which involves AKT phosphorylation.

Dihydroartemisinin attenuates lipopolysaccharide­induced acute lung injury in mice by suppressing NF­κB signaling in an Nrf2­dependent 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 anti­organizational fibrosis and anti­neuronal 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 LPS­induced infiltration of inflammatory cells, the elevation of myeloperoxidase activity, oxidative stress and the production of pro­inflammatory cytokines, including interleukin (IL)­1ß, tumor necrosis factor­α, and IL­6. Furthermore, DHA reduced the LPS­induced inflammatory response by suppressing the degradation of I­κB and the nuclear translocation of nuclear factor κ­light­chain­enhancer of activated B cells (NF­κB)/p65 in vivo and in vitro. DHA activated the nuclear factor­erythroid 2 related factor 2 (Nrf2) pathway, which was suppressed by LPS treatment. The Nrf2 inhibitor, ML385, diminished the protective effects of DHA against LPS­induced inflammation in macrophages. On the whole, the findings of this study demonstrate that DHA exerts therapeutic effects against LPS­induced ALI by inhibiting the Nrf2­mediated NF­κB activation in macrophages. The present study also confirmed the therapeutic effects of DHA in mice with LPS­induced ALI. Thus, these findings demonstrate that DHA exhibits anti­inflammatory activities and may be a therapeutic candidate for the treatment of ALI.

The protective effect of oleanolic acid on NMDA-induced MLE-12 cells apoptosis and lung injury in mice by activating SIRT1 and reducing NF-κB acetylation.

Overactivation of the N-methyl-d-aspartate (NMDA) receptor promotes oxidative stress, aggravates the inflammatory response and induces excitotoxic lung injury. NMDA is a synthetic agonist that selectively activates the NMDA receptor. Oleanolic acid (OA) is a natural anti-inflammatory and antioxidant compound. This study investigated the effect and possible mechanism of OA on NMDA-induced acute lung injury (ALI) in mice. OA pretreatment alleviated NMDA-induced histological lung changes and ameliorated pulmonary oedema and pulmonary permeability. At the same time, OA inhibited inflammatory cell infiltration and decreased the levels of tumour necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1ß in the lung and bronchoalveolar lavage fluid (BALF). OA markedly decreased malondialdehyde (MDA) production and increased the superoxide dismutase (SOD) and glutathione (GSH) contents of the lung in vivo. Meanwhile, we first found that NMDA increased LDH activity and decreased cell viability, and induced oxidative stress and apoptosis in mouse lung epithelial (MLE)-12 cells. By employing SRT1720 and sirtinol, the activator and inhibitor of sirtuin 1 (SIRT1), we found that SRT1720 partially eliminated the increase in ROS，and sirtinol further promoted the increase in ROS caused by NMDA. OA increased MLE-12 cells viability and attenuated oxidative stress after NMDA challenge in vitro. OA suppressed NMDA-induced MLE-12 cells apoptosis, while sirtinol inhibited the effect of OA. In addition, OA significantly upregulated the levels of SIRT1, nuclear-related factor 2(Nrf2) and Bcl-2 protein and downregulated the levels of acetylated nuclear factor-kappa B (NF-κB), NLRP3 and Bax protein. In conclusion, OA attenuated NMDA-induced excitotoxic lung injury, potentially through its anti-inflammatory, antioxidative stress and anti-apoptotic effects. The mechanism may be related to activating SIRT1 and reducing NF-κB acetylation.

[ERα36 is involved in the proliferation promotion and anti-apoptosis effects of icaritin on MG63 cells].

The mechanism for icaritin to improve postmenopausal osteoporosis (PMOP) has not been clarified. The aim of this study was to investigate the role of estrogen receptor α36 (ERα36) in the proliferation promotion and anti-apoptosis effects of icaritin on osteoblasts and the underlying mechanism of downstream signal transduction. The ERα36 knockdown human osteosarcoma MG63 cell model was constructed by transfection of shRNA vector. Cell proliferation was detected by CCK-8, the apoptosis was detected by flow cytometry, and the activation of ERK and AKT signaling pathways was detected by Western blot. The results showed that the effects of icaritin on the proliferation and apoptosis of MG63 cells were significantly decreased after ERα36 knockdown, and icaritin could up-regulate the levels of ERK and AKT phosphorylation in MG63 cells, which could be reduced by ERα36 knockdown. The effect of icaritin on the proliferation of MG63 cells was significantly decreased by pretreating the cells with U0126 (an ERK signaling pathway blocker) and LY294002 (an AKT signaling pathway blocker), respectively. Furthermore, anti-apoptotic effect of icaritin on MG63 cells was significantly decreased after the cells were pretreated with U0126, but not with LY294002. These results suggest that icaritin exerts proliferation promotion and anti-apoptosis effects on osteoblasts through ERα36 and its downstream ERK and AKT signaling pathways.