CRBN knockdown mitigates lipopolysaccharide-induced acute lung injury by suppression of oxidative stress and endoplasmic reticulum (ER) stress associated NF-κB signaling

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.

TMEM16A deficiency in alveolar type 2 epithelial cells protected against endoplasmic reticulum stress-induced ferroptosis during acute lung injury

Transmembrane protein 16A (TMEM16A) is one of the members of the ten-member family of "transmembrane protein 16", playing critical roles in infection and solid organ injury. Acute lung injury (ALI) is a devastating disease which could be triggered by sepsis, trauma, and ischemia reperfusion. However, molecular mechanisms contributing to ALI are poorly understood at presently. In this study, we investigated the role of TMEM16A in sepsis-induced ALI using TMEM16A-deficient mice. Sepsis-induced ALI model was established by intratracheal injection of lipopolysaccharide (LPS). Our results showed that LPS stimulation significantly upregulated the expression levels of TMEM16A in lung tissues and in alveolar epithelial type II (AT2) cells. Knockout of TMEM16A in AT2 cells significantly improved pulmonary function and alleviated lung pathological injury in LPS-treated mice. Meanwhile, TMEM16A deficiency also inhibited endoplasmic reticulum (ER) stress and ferroptosis in AT2 cells from LPS-treated mice. In vitro experiments further demonstrated that ER stress and ferroptosis were inhibited after TMEM16A was knocked out. Furthermore, we used ER stress inducer thapsigargin to induce ER stress in TMEM16A-null AT2 cells and found that the induction of ER stress abolished the inhibition of ferroptosis by TMEM16A deficiency in LPS-treated AT2 cells. Finally, we disclosed that pharmacological inhibition of TMEM16A by shikonin also showed similar therapeutic effect on LPS-induced ALI in vivo. In conclusion, TMEM16A deficiency in AT2 cells could alleviate sepsis-induced ALI by decreasing ER stress-induced ferroptosis during ALI.

IRE1α/XBP-1 promotes β-catenin signaling activation of airway epithelium in lipopolysaccharide-induced acute lung injury

BACKGROUND

Acute lung injury (ALI), along with the more severe condition--acute respiratory distress syndrome (ARDS), is a major cause of respiratory failure in critically ill patients with high morbidity and mortality. Inositol-requiring protein 1α (IRE1α)/X box protein-1 (XBP1) pathway was proved to regulate lipopolysaccharide (LPS)-induced lung injury and inflammation. Yet, its role on epithelial β-catenin in LPS-induced ALI remains to be elucidated.

METHODS

LPS-induced models were generated in mice (5 mg/kg) and Beas-2B cells (200 μg/mL). Two selective antagonists of IRE1α (4μ8c and STF-083010) were respectively given to LPS-exposed mice and cultured cells.

RESULTS

Up-regulated expression of endoplasmic reticulum (ER) stress markers immunoglobulin-binding protein (BIP) and spliced X box protein-1(XBP-1s) was detected after LPS exposure. Besides, LPS also led to a down-regulated total β-catenin level in the lung and Beas-2B cells, with decreased membrane distribution as well as increased cytoplasmic and nuclear accumulation, paralleled by extensively up-regulated downstream targets of the Wnt/β-catenin signaling. Treatment with either 4μ8c or STF-083010 not only significantly attenuated LPS-induced lung injury and inflammation, but also recovered β-catenin expression in airway epithelia, preserving the adhesive function of β-catenin while blunting its signaling activity.

CONCLUSION

These results illustrated that IRE1α/XBP1 pathway promoted the activation of airway epithelial β-catenin signaling in LPS-induced ALI.

The Relationship Between the Expression of CRBN in Peripheral Blood and the Severity and Prognosis of Adult Sepsis

Objective

To investigate the correlation between the expression of cereblon (CRBN) protein in peripheral blood and the severity and prognosis of sepsis.

Methods

A total of 130 patients with sepsis admitted to our hospital were selected as the observation subjects (sepsis group). The patients were divided into mild group, moderate group and severe group according to their conditions. The patients were divided into survival group and death group according to their living conditions within 28 days after admission. 130 health individuals were selected as the control group. The levels of CRBN mRNA, CRP and PCT in peripheral blood were detected.

Results

The levels of serum CRBN mRNA, CRP, and PCT in patients with sepsis were higher than those in the control group (P<0.05); As the condition worsens, the levels of CRBN mRNA, CRP, and PCT gradually increase, and there are statistically significant differences among patients with mild, moderate, and severe sepsis; Correlation analysis showed that the expression of CRBN mRNA in sepsis patients was positively correlated with CRP, PCT levels, APACHE II score and SOFA score (P<0.05); the 28-day cumulative survival rate of patients with high CRBN mRNA expression was significantly lower than that of patients with low CRBN mRNA expression (P<0.05); compared with the survival group, the levels of serum CRBN mRNA, CRP and PCT in the death group were significantly higher (P<0.05); the AUC of death in sepsis patients diagnosed by CRBN mRNA, CRP and PCT was 0.961, the combined diagnostic efficacy was higher than that of single detection (P<0.05).

Conclusion

The expression level of CRBN in the peripheral blood of patients with sepsis is increased, which is related to the severity and prognosis of the patients. The combination of CRP and PCT has certain diagnostic value for the death of sepsis patients.

Involvement of IGF1 in endoplasmic reticulum stress contributes to cataract formation through regulating Nrf2/NF-κB signaling

Endoplasmic reticulum (ER) stress is reportedly involved in the development of ophthalmic diseases. This study aimed to investigate the role and potential mechanism of insulin-like growth factor 1 (IGF1) in ER stress. A mouse cataract model was constructed by subcutaneous injection of sodium selenite, and sh-IGF1 was used to evaluate the effect of silencing IGF1 on cataract progression. Slit-lamp and histological examination of the lens were performed to examine lens damage. The regulatory effects of IGF1 on inflammatory responses, oxidative stress, and ER stress were evaluated using ELISA, reverse transcription-quantitative PCR (RT-qPCR), and immunoblotting analysis. Tunicamycin was used to induce ER stress in the lens of epithelial cells. The NF-E2 related factor-2 (Nrf2) inhibitor ML385 and nuclear factor-κB (NF-κB) agonist diprovocim were used to confirm whether IGF1 regulates inflammation and ER stress through Nrf2/NF-κB signaling. Silencing IGF1 alleviated lens damage and reduced lens turbidity in the cataract mice. Silencing IGF1 inhibited inflammatory response, oxidative stress and ER stress response. Meanwhile, IGF1 was highly expressed in sodium selenite-treated lens epithelial cells. The ER stress agonist tunicamycin suppressed cell viability as well as induced ER stress, oxidative stress and inflammation. Silencing IGF1 increased cell viability, EdU-positive rate and migration. Also, silencing of IGF1 reduced inflammation and ER stress via regulating Nrf2/NF-κB pathway. This study reveals silencing IGF1 attenuated cataract through regulating Nrf2/NF-κB signaling, which shares novel insights into the underlying mechanism of cataract and provides potential therapeutic target for cataract.

Thalidomide interaction with inflammation in idiopathic pulmonary fibrosis

The "Thalidomide tragedy" is a landmark in the history of the pharmaceutical industry. Despite limited clinical trials, there is a continuous effort to investigate thalidomide as a drug for cancer and inflammatory diseases such as rheumatoid arthritis, lepromatous leprosy, and COVID-19. This review focuses on the possibilities of targeting inflammation by repurposing thalidomide for the treatment of idiopathic pulmonary fibrosis (IPF). Articles were searched from the Scopus database, sorted, and selected articles were reviewed. The content includes the proven mechanisms of action of thalidomide relevant to IPF. Inflammation, oxidative stress, and epigenetic mechanisms are major pathogenic factors in IPF. Transforming growth factor-β (TGF-β) is the major biomarker of IPF. Thalidomide is an effective anti-inflammatory drug in inhibiting TGF-β, interleukins (IL-6 and IL-1β), and tumour necrosis factor-α (TNF-α). Thalidomide binds cereblon, a process that is involved in the proposed mechanism in specific cancers such as breast cancer, colon cancer, multiple myeloma, and lung cancer. Cereblon is involved in activating AMP-activated protein kinase (AMPK)-TGF-β/Smad signalling, thereby attenuating fibrosis. The past few years have witnessed an improvement in the identification of biomarkers and diagnostic technologies in respiratory diseases, partly because of the COVID-19 pandemic. Hence, investment in clinical trials with a systematic plan can help repurpose thalidomide for pulmonary fibrosis.

Polystyrene-microplastics and DEHP co-exposure induced DNA damage, cell cycle arrest and necroptosis of ovarian granulosa cells in mice by promoting ROS production

The joint pollution of microplastics (MPs) and di-(2-ethylhexyl) phthalic acid (DEHP) often occurs, and consequently poses a serious threat to human and animal health, which has attracted widespread attention. However, the damage to the female mammalian ovary caused by the single exposure and co-exposure of MPs and DEHP and its specific mechanisms are not clear. Here, we established mouse models of single and co-exposures to polystyrene-microplastics (PS-MPs) and DEHP. The results showed that exposed to 100 mg/L PS-MPs and 200 mg/kg DEHP for 35 days destroyed the ovarian granulosa cell layer of mice, leading to follicular fragmentation and atresia. We cultured ovary granulosa cells in vitro to perform further mechanism studies and found that PS-MPs and DEHP had synergistic effects. Both of them promoted the excessive production of ROS and induced oxidative stress by triggering the CNR1/CRBN/YY1/CYP2E1 signaling axis, which in turn caused DNA oxidative damage. Additionally, we provided compelling evidence that oxidative stress mediated-hippo signaling pathway played a critical role in PS-MPs and DEHP caused ovary damage, resulting in ovarian granulosa cell cycle arrest and necroptosis. Using oxidative stress inhibitor AM251 or DAS could reverse these changes markedly and alleviate the reproductive toxicity caused by PS-MPs and DEHP, effectively. Overall, these results demonstrated that co-exposure of PS-MPs and DEHP adversely affected the integrity of ovary granulosa cell layer, resulting in DNA oxidative damage, cell cycle arrest and increased necroptosis of mouse ovarian granulosa cells by inducing oxidative stress. Our study shed new light on the co-exposure toxicity of PS-MPs and DEHP, provided novel insights for the reproductive toxicity of PS-MPs combined exposure with DEHP in female animals from a new free radical generation pathway perspective.

ALCAM Deficiency Alleviates LPS-Induced Acute Lung Injury by Inhibiting Inflammatory Response

We investigated the effects and underlying mechanisms of activated leukocyte adhesion molecule (ALCAM) on acute lung injury (ALI) by using lipopolysaccharide (LPS)-induced ALI animal model and LPS-induced inflammation in vitro. In LPS-stimulated mice, ALCAM deficiency relieved lung injury, which manifested as reduced pathological changes in the lung tissue, reduced pulmonary edema, and reduced vascular permeability. Furthermore, we demonstrated that ALCAM deficiency reduced the infiltration of inflammatory cells, including neutrophil, eosinophil, and macrophages; the release of inflammatory cytokines, including IL-1β, IL-6, TNF-α, and COX2; and reduced the protein level of TLR4/NF-κB pathway (TLR4, MyD88, p-IkBɑ, and p-NF-κB p65). We also demonstrated that ALCAM deficiency reduced the expression of oxidative stress-related proteins (Nrf-2, HO-1, and NQO-1) and endoplasmic reticulum stress-related proteins (CHOP, GRP78, ATF-6, and p-eIF2ɑ). In addition, in LPS-induced inflammation in vitro, ALCAM overexpression promoted inflammatory response, oxidative stress, and ER stress. We established that ALCAM deficiency can suppress the ALI process by reducing inflammatory response, oxidative stress, and endoplasmic reticulum stress.

rmMANF prevents sepsis-associated lung injury via inhibiting endoplasmic reticulum stress-induced ferroptosis in mice

Ferroptosis plays a critical role in LPS-induced acute lung injury and is modulated by endoplasmic reticulum stress (ERS). As a typical ER stress-responsive protein, recently mesencephalic astrocyte-derived neurotrophic factor (MANF) has been demonstrated to attenuate LPS-induced acute lung injury (ALI) through repressing macrophage activation. However, whether MANF exerts a preventive role on ferroptosis and excess ER stress remains unclear. Here, we first built a protein-protein interaction (PPI) network to obtain potential interacting proteins related to MANF through STRING and GeneMANIA. Then, male C57BL/6J mice were used to build a model of LPS-induced lung injury. Two days before LPS injection, the tail vein injected recombinant murine MANF (rmMANF) at 750 μg/kg. Twenty-four hours after the LPS injection, the histopathological changes and damage in the lung tissues were detected and scored by HE staining and TUNEL assay, respectively. Endogenous MANF levels, oxidative stress markers (GSH, SOD, CAT, and MDA), ERS markers (GRP78, PERK, and ATF4), and the ferroptosis markers (iron, GPX4, and 4-HNE) in the lung tissues were measured by IHC, western blotting, and commercial kits. Our results showed that LPS induced significant lung injury to the increase in MPO, MDA, and 4-HNE, a decrease in GPX4 and GSH, SOD, CAT, and total iron accumulation in LPS-exposed mice. Simultaneously, GRP78/PERK/ATF4 pathway was notably activated by LPS, accompanied by the down-regulation of MANF. Furthermore, rmMANF pretreatment markedly prevented LPS-induced lung tissue injury and ferroptosis characteristics with the increased GPX4 level in sepsis mice. Finally, we found that LPS-induced oxidative stress and activation of the GRP78/PERK/ATF4 pathway were significantly restrained by rmMANF pretreatment, except for endogenous MANF level. Overall, rmMANF pretreatment can prevent sepsis-associated lung injury by inhibiting ER stress-induced ferroptosis in mice.

Insulin-like growth factor-1 reduces hyperoxia-induced lung inflammation and oxidative stress and inhibits cell apoptosis through PERK/eIF2α/ATF4/CHOP signaling

Background: Insulin-like growth factor-1 (IGF-1), a member of the insulin family, has a high degree of homology with insulin and exhibits anti-inflammatory and anti-oxidative stress properties. However, the potential protective effect of IGF-1 on hyperoxia-induced lung injury remains unknown. In this study, we aimed to explore the effects and mechanism of action of IGF-1 in hyperoxia-induced lung injury in neonatal rats. Materials and Methods: Hematoxylin-eosin staining was used to observe pathological changes in lung tissue; transmission electron microscopy was used to examine the ultrastructure, and ELISA was used to detect the level of pro-inflammatory cytokines in bronchoalveolar lavage fluid. Further, malondialdehyde, glutathione, and superoxide dismutase activities in lung tissue were evaluated. TUNEL staining was used to detect cell apoptosis, and western blot analysis was used to detect the expression of Bax, Bcl-2, Caspase-3, p-PERK, p-eIF2α, ATF4, and CHOP in the lung tissue. Moreover, the wet/dry weight ratio of lung tissue was determined. Results: Intraperitoneal injection of IGF-1 effectively reduced lung tissue damage induced by hyperoxia; production of inflammatory cells and release of pro-inflammatory cytokines, oxidative stress, and cell apoptosis. Further, IGF-1 down-regulated the expression of ATF4, CHOP, and Bax/Bcl-2, and inhibited the phosphorylation of PERK and eIF2α. Conclusion: The results suggest that IGF-1 reduces hyperoxia-induced lung inflammation and oxidative stress in neonatal rats through the PERK/eIF2α/ATF4/CHOP signaling pathway and inhibits cell apoptosis.

Myeloid-Specific Pyruvate-Kinase-Type-M2-Deficient Mice Are Resistant to Acute Lung Injury

Infiltration of polymorphonuclear neutrophils (PMNs) plays a central role in acute lung injury (ALI). The mechanisms governing PMN inflammatory responses, however, remain incompletely understood. Based on our recent study showing a non-metabolic role of pyruvate kinase type M2 (PKM2) in controlling PMN degranulation of secondary and tertiary granules and consequent chemotaxis, here we tested a hypothesis that Pkm2-deficient mice may resist ALI due to impaired PMN inflammatory responses. We found that PMN aerobic glycolysis controlled the degranulation of secondary and tertiary granules induced by fMLP and PMA. Compared to WT PMNs, Pkm2-deficient (Pkm2-/-) PMNs displayed significantly less capacity for fMLP- or PMA-induced degranulation of secondary and tertiary granules, ROS production, and transfilter migration. In line with this, myeloid-specific Pkm2-/- mice exhibited impaired zymosan-induced PMN infiltration in the peritoneal cavity. Employing an LPS-induced ALI mouse model, LPS-treated Pkm2-/- mice displayed significantly less infiltration of inflammatory PMNs in the alveolar space and a strong resistance to LPS-induced ALI. Our results thus reveal that PKM2 is required for PMN inflammatory responses and deletion of PKM2 in PMN leads to an impaired PMN function but protection against LPS-induced ALI.

Endoplasmic reticulum stress in airway hyperresponsiveness

Airway hyperresponsiveness(AHR) is a major clinical phenomenon in lung diseases (asthma, COPD and pulmonary fibrosis) and not only a high-risk factor for perioperative airway spasm leading to hypoxaemia, haemodynamic instability and even "silent lung", but also a potential risk for increased mortality from underlying diseases (e.g. asthma, COPD). Airway reactivity is closely linked to airway inflammation, remodelling and increased mucus secretion, and endoplasmic reticulum stress is an important mechanism for the development of these pathologies. This review, therefore, focuses on the effects of endoplasmic reticulum stress on the immune cells involved in airway hyperreactivity (epithelial cells, dendritic cells, eosinophils and neutrophils) in inflammation and mucus & sputum secretion; and on the differentiation and remodelling of airway smooth muscle cells and epithelial cells. The aim is to clarify the mechanisms associated with endoplasmic reticulum stress in airway hyperresponsiveness and to find new ideas and methods for the prevention of airway hyperresponsiveness in the perioperative period.

Calcium-activated nucleotides 1 (CANT1)-driven nuclear factor-k-gene binding (NF-ĸB) signaling pathway facilitates the lung cancer progression

Dysregulation of calcium-activated nucleotides 1 (CANT1) has been observed in different organs. Thus, its biological function in cancer has increasingly attracted researchers. The current work aims to study the CANT1 role in lung cancer and understand the underlying pathological mechanisms. High amplification of CANT1 was observed in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) tissues compared to normal tissues. The high-CANT1 patients showed a dismal prognosis in comparison with the low-CANT1 patients. Highly expressed CANT1 was significantly associated with the N stage of LUSC patients. Ectopic expression of CANT1 conspicuously increased the proliferation and viability of A549 cells. Conversely, CANT1 depletion resulted in adverse effects in H1299 cells. CANT1 depletion also resulted in the retardation of tumor growth in vivo. Mechanically, we found that CANT1 could elevate NF-ĸB (nuclear factor-k-gene binding) transcriptional activity in a concentration-dependent manner. This regulatory relationship was also established by the Western blot technique. Inhibiting NF-ĸB can significantly blunt the increased NF-κ-B Inhibitor-α (IκBα) expression caused by CANT1 overexpression in A549 cells. In conclusion, highly amplified CANT1 promotes the proliferation and viability of lung cancer cells. We also elucidate a new signaling axis of CANT1-NF-ĸB in lung cancer. This approach might be a promising strategy for lung cancer treatment.

[2, 3, 5, 4'-tetrahydroxystilbene-2-O-β-d-glucoside alleviates lipopolysaccharide-induced acute lung injury in rats]

OBJECTIVE

To observe the protective effect of 2, 3, 5, 4'-tetrahydroxystilbene-2-O-β-d-glucoside (TSG) against lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats and explore the underlying mechanism.

METHODS

Thirty-six SD rats were randomized equally into 4 groups: the normal control group, ALI model group, and low- and high-dose TSG groups (treated with 50 and 100 mg/kg TSG via intragastric administration, respectively). In all but the normal control group, the rats were subjected to tail vein injection of LPS to induced ALI. The rats were euthanized at 6 h after the injection for pathological examination of the lungs. The wet/dry weight ratio (W/D) of the lungs were calculated, and superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in the lung tissues and serum levels of TNF-α and IL-6 were determined. Western blotting was performed to detect the levels of NF-κB p65 in the lungs.

RESULTS

Compared with those in LPS group, the TSGtreated rats showed significantly milder lung pathologies (P < 0.001) and had lower serum TNF-α and IL-6 levels (P < 0.001) and W/D of the lung tissues (P < 0.001), higher SOD activity (P < 0.001) and lower MDA content in the lungs (P < 0.001), and significantly lower expression of NF-κB p65 in the lungs (P < 0.001). None of these indices showed significant differences between the lowand high-dose TSG treatment groups (P>0.05).

CONCLUSIONS

TSG can ameliorate LPS-induced ALI in rats possibly by suppressing the NF-κB pathway to improve the antioxidant capacity and decrease the release of inflammatory factors.

Circ_0114428 Regulates Sepsis-Induced Kidney Injury by Targeting the miR-495-3p/CRBN Axis

Septic acute kidney injury (AKI) is considered as a severe and common complication of sepsis, with complex pathogenesis. Recently, Circular RNA (circRNA) is considered to be implicated in this disease. This study was intended to elucidate the role of circ_0114428 and the potential mechanism of action in sepsis-induced kidney injury. Sepsis-induced kidney injury cell model was established in human kidney 2 (HK2) cells by the treatment of lipopolysaccharide (LPS). The expression of circ_0114428, CRBN mRNA, and miR-495-3p was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability was assessed by cell counting kit-8 (CCK-8) assay. The inflammatory response was monitored according to the release of proinflammatory factors by enzyme-linked immunosorbent assay (ELISA). Cell apoptosis was evaluated by flow cytometry assay. The activities of oxidative indicators were examined using the corresponding kits. Endoplasmic reticulum (ER) stress-related proteins and CRBN protein were quantified by western blot. RNA immunoprecipitation (RIP) assay was performed to ensure whether circ_0114428 could interact with Argonaute 2 (Ago2) protein. The potential miRNAs targeted by circ_0114428 were predicted by the bioinformatics tool and screened by RNA pull-down assay. The interaction between miR-495-3p and circ_0114428 or CRBN was validated by dual-luciferase reporter assay. The results showed that circ_0114428 and CRBN were upregulated in septic AKI serum specimens and LPS-induced HK2 cells. Circ_0114428 knockdown attenuated LPS-induced apoptosis, inflammation, oxidative stress, and ER stress, which were rescued by CRBN overexpression. Further analysis revealed that miR-495-3p was targeted by circ_0114428 and directly bound to CRBN, and circ_0114428 regulated CRBN expression by sponging miR-495-3p. Besides, miR-495-3p inhibition also reversed the effects of circ_0114428 knockdown. In conclusion, circ_00114428 knockdown attenuated LPS-induced HK2 cell injury by regulating CRBN expression via targeting miR-495-3p.

MicroRNA-490-3p inhibits inflammatory responses in LPS-induced acute lung injury of neonatal rats by suppressing the IRAK1/TRAF6 pathway

Acute lung injury (ALI) is a main reason for neonatal death. Studying the molecular mechanism behind neonatal ALI is critical for the development of therapeutic strategies. The present study explored microRNA (miR)-490-3p-mediated regulatory effects on lipopolysaccharide (LPS)-induced neonatal ALI. Initially, LPS (10 mg/kg body weight) was injected to 3-8 day old neonatal SD rats to induce ALI, and LPS (100 ng/ml) was used to treat lung epithelial cells to construct an ALI model in vitro. Next, miR-490-3p, pro-inflammatory factors (that included IL-1β, IL-6 and TNFα), interleukin 1 receptor associated kinase 1 (IRAK1) and TNF receptor associated factor 6 (TRAF6) mRNA expression levels in lung tissues and epithelial cells were assessed via reverse transcription-quantitative PCR. In addition, miR-490-3p mimics were adopted to construct its overexpressed cell model, and Cell Counting Kit-8 and BrdU assays were conducted to assess cell viability. Furthermore, the miR-490-3p target, IRAK was predicted by bioinformatics analysis and verified via Dual-luciferase reporter gene assay. The results revealed that miR-490-3p was markedly downregulated in an LPS-induced rat ALI model, while IL-1β, IL-6, TNFα, IRAK1 and TRAF6 were all upregulated and negatively correlated with miR-490-3p expression. Moreover, overexpressed miR-490-3p significantly inhibited LPS-induced lung epithelial cell injury and inflammatory response. Mechanistically, miR-490-3p targeted and attenuated IRAK1 expression, which thus inactivated the LPS-mediated TRAF6/NF-κB pathway. Overall, the present study indicated that miR-490-3p overexpression significantly inhibited LPS-induced ALI and inflammatory responses by restricting the IRAK1/TRAF6 pathway.

Knockout of cytochrome P450 1A1 enhances lipopolysaccharide-induced acute lung injury in mice by targeting NF-κB activation

Acute lung injury (ALI) is accompanied by overactivation of multiple pro-inflammatory factors. Cytochrome P450 1A1 (CYP1A1) has been shown to aggravate lung injury in response to hyperoxia. However, the relationship between CYP1A1 and lipopolysaccharide (LPS)-induced ALI is unknown. In this study, CYP1A1 was shown to be upregulated in mouse lung in response to LPS. Using CYP1A1-deficient (CYP1A1-/-) mice, we found that CYP1A1 knockout enhanced LPS-induced ALI, as evidenced by increased TNF-α, IL-1β, IL-6, and nitric oxide in lung; these effects were mediated by overactivation of NF-κB and iNOS. Furthermore, we found that aspartate aminotransferase, lactate dehydrogenase, creatine kinase, and creatinine levels were elevated in serum of LPS-induced CYP1A1-/- mice. Altogether, these data provide novel insights into the involvement of CYP1A1 in LPS-induced lung injury.