Taurine enhances the protective effect of Dexmedetomidine on sepsis-induced acute lung injury via balancing the immunological system

The protective effect of ginsenoside Rg1 against sepsis-induced lung injury through PI3K-Akt pathway: insights from molecular dynamics simulation and experimental validation

Sepsis-induced acute lung injury (SALI) poses a significant threat with high incidence and mortality rates. Ginsenoside Rg1 (GRg1), derived from Ginseng in traditional Chinese medicine, has been found to reduce inflammation and protect lung epithelial cells against tissue damage. However, the specific roles and mechanisms by which GRg1 mitigates SALI have yet to be fully elucidated. In this context, we employed a relevant SALI mouse model, alongside network pharmacology, molecular docking, and molecular dynamics simulation to pinpoint GRg1's action targets, complemented by in vitro assays to explore the underlying mechanisms. Our research shows that GRg1 alleviates CLP-induced SALI, decreasing lung tissue damage and levels of serum proinflammatory factor IL-6, TNF-α, and IL-1β, also enhancing the survival rate of CLP mice. A total of 116 common targets between GRg1 and ALI, with specific core targets including AKT1, VEGFA, SRC, IGF1, ESR1, STAT3, and ALB. Further in vitro experiments assessed GRg1's intervention effects on MLE-12 cells exposed to LPS, with qRT-PCR analysis and molecular dynamics simulations confirming AKT1 as the key target with the favorable binding activity for GRg1. Western blot results indicated that GRg1 increased the Bcl-2/Bax protein expression ratio to reduce apoptosis and decreased the high expression of cleaved caspase-3 in LPS-induced MLE-12 cells. More results showed significant increases in the phosphorylation of PI3K and AKT1. Flow cytometric analysis using PI and Annexin-V assays further verified that GRg1 decreased the apoptosis rate in LPS-stimulated MLE-12 cells (from 14.85 to 6.54%, p < 0.05). The employment of the AKT1 inhibitor LY294002 confirmed these trends, indicating that AKT1's inhibition negates GRg1's protective effects on LPS-stimulated MLE-12 cells. In conclusion, our research highlights GRg1's potential as an effective adjunct therapy for SALI, primarily by inhibiting apoptosis in alveolar epithelial cells and reducing pro-inflammatory cytokine secretion, thus significantly enhancing the survival rates of CLP mice. These beneficial effects are mediated through targeting AKT1 and activating the PI3K-AKT pathway.

Evaluation of the efficacy of silymarin and dexmedetomidine on kidney and lung tissue in the treatment of sepsis in rats with cecal perforation

Sepsis is a systemic inflammatory response syndrome that develops in the host against microorganisms. This response develops away from the primary infection site and results in end-organ damage. The present study aimed to investigate the protective and therapeutic effects on lung and kidney tissue of silymarin (S) and dexmedetomidine (DEX) applied 1 h before and after sepsis induced by the cecal ligation and puncture (CLP) method in rats. A total of 62 rats was randomly divided into eight groups: i) Control (n=6); ii) cecal perforation (CLP; n=8); iii) S + CLP (n=8; S + CLP; S administered 1 h before CPL); iv) CLP + S (n=8; S administered 1 h after CLP); v) DEX + CLP (n=8; D + CLP; DEX administered 1 h before CLP); vi) CLP + D (n=8; DEX administered 1 h after CLP); vii) SD + CLP (n=8; S and DEX administered 1 h before CLP) and viii) CLP + SD (n=8; S and DEX administered 1 h after CLP). After the cecum filled with stool, it was tied with 3/0 silk under the ileocecal valve and the anterior surface of the cecum was punctured twice with an 18-gauge needle. A total of 100 mg/kg silymarin and 100 µg/kg DEX were administered intraperitoneally to the treatment groups. Lung and kidney tissue samples were collected to evaluate biochemical and histopathological parameters. In the histopathological examination, all parameters indicating kidney injury; interstitial edema, peritubular capillary dilatation, vacuolization, ablation of tubular epithelium from the basement membrane, loss of brush border in the proximal tubule epithelium, cell swelling and nuclear defragmentation; were increased in the CLP compared with the control group. Silymarin administration increased kidney damage, including ablation of tubular epithelium from the basement membrane, compared with that in the CLP group. DEX significantly reduced kidney damage compared with the CLP and silymarin groups. The co-administration of DEX + silymarin decreased kidney damage, although it was not as effective as DEX-alone. To conclude, intraperitoneal DEX ameliorated injury in CLP rats. DEX + silymarin partially ameliorated injury but silymarin administration increased damage. As a result, silymarin has a negative effects with this dosage and DEX has a protective effect. In the present study, it was determined that using the two drugs together had a greater therapeutic effect than silymarin and no differences in the effects were not observed any when the application times of the agents were changed.

Design, synthesis, and bioactivity evaluation of novel amide/sulfonamide derivatives as potential anti-inflammatory agents against acute lung injury and ulcerative colitis

The uneven regulation of inflammation is related to various diseases, making anti-inflammation a potential option for the development of novel therapies. In this study, we designed and synthesized a total of fifty-eight novel amide/sulfonamide derivatives based on our previously reported anti-inflammatory compounds. The anti-inflammatory activities of these compounds were evaluated upon LPS-stimulated J774A.1 cells. Compounds 11a, 11b, 11c, and 11d potently reduced the release of IL-6 and TNF-α, and decreased the mRNA level of cytokines in J774A.1 cells. The most active compound 11d with IC50 value of 0.61 μM for IL-6 inhibition, and 4.34 μM for TNF-α inhibition restored IκB α and inhibited the translocation of phosphorylated p65 into the nucleus. In vivo evaluation indicated that 11d improved LPS-induced ALI and alleviated DSS-induced ulcerative colitis in mice. In conclusion, these results suggested compound 11d can be a new lead structure for the development of anti-inflammatory drugs against ALI and ulcerative colitis.

Protective effects of Descurainia sophia seeds extract and its fractions on pulmonary edema by untargeted urine and serum metabolomics strategy

Background: Descurainia sophia seeds (DS) is a herbal medicine in traditional Chinese medicine (TCM) for treating lung diseases. We aimed to evaluate the therapeutic effect of DS and five of its fractions upon pulmonary edema (PE) through metabolomics analysis (MA) of urine and serum samples of rats. Methods: A PE model was established by intrathoracic injection of carrageenan. Rats were pretreated with DS extract or its five fractions (polysaccharides (DS-Pol); oligosaccharides (DS-Oli); flavonoid glycosides (DS-FG); flavonoid aglycone (DS-FA); fat oil fraction (DS-FO)) for seven consecutive days. Forty-eight hours after carrageenan injection, lung tissues were subjected to histopathology. MA of urine and serum was done by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry, respectively. Principal component analysis and orthogonal partial least squares-discriminant analysis were operated for the MA of rats and potential biomarkers related to treatment. Heatmaps and metabolic networks were constructed to explore how DS and its five fractions act against PE. Results: DS and its five fractions could all attenuate pathologic lung injury to different degrees, and DS-Oli, DS-FG, and DS-FO had a more potent effect compared with DS-Pol and DS-FA. DS-Oli, DS-FG, DS-FA, and DS-FO could regulate the metabolic profiles of PE rats, but DS-Pol was less potent. According to MA, the five fractions could improve PE to some degree due to their anti-inflammatory, immunoregulatory, and renoprotective activities by mediating the metabolism of taurine, tryptophan, and arachidonic acid. However, DS-Oli, DS-FG, and DS-FO had more important roles in edema-fluid reabsorption, and reduction of vascular leakage through regulating the metabolism of phenylalanine, sphingolipid and bile acid. Finally, heatmaps and hierarchical clustering analysis indicated DS-Oli, DS-FG, and DS-FO to be more efficacious than DS-Pol or DS-FA against PE. The five fractions of DS had a synergistic effect on PE from different aspects, thereby constituting the entire efficacy of DS. DS-Oli, DS-FG, or DS-FO could be used as an alternative to DS. Conclusion: MA combined with use of DS and its fractions provided novel insights into the mechanism of action of TCM.

Dexmedetomidine alleviates acute lung injury by promoting Tregs differentiation via activation of AMPK/SIRT1 pathway

OBJECTIVES

To explore the anti-inflammatory effect and the potential mechanism of dexmedetomidine in ARDS/ALI.

MATERIALS AND METHODS

C57BL/6 mice and EL-4 cells were used in this research. The ALI model was established by CLP. The level of inflammatory cytokines in the lung and blood, the severity of lung injury, the expression of Foxp3, and the proportion of Tregs were detected before and after dexmedetomidine treatment. The expression of the AMPK/SIRT1 after dexmedetomidine treatment was detected in vivo and in vitro. After blocking the AMPK/SIRT1 pathway or depleting Tregs in vivo, the level of the inflammatory response, tissue injury, and Tregs differentiation were detected again to clarify the effect of dexmedetomidine.

RESULTS

Dexmedetomidine significantly reduced systemic inflammation and lung injury in CLP mice. Dexmedetomidine enhanced the Foxp3 expression in the lungs and the frequency of Tregs in the spleen. Dexmedetomidine up-regulated the protein expression of p-AMPK and SIRT1 in lungs and EL-4 cells and facilitated the differentiation of naïve CD4⁺ T cells into Tregs in vitro. Meanwhile, DEX also increased the expression of Helios in Treg cells.

CONCLUSIONS

DEX could improve ARDS/ALI by facilitating the differentiation of Tregs from naïve CD4⁺ T cells via activating the AMPK/SIRT1 pathway.

Plasma microRNA and metabolic changes associated with pediatric acute respiratory distress syndrome: a prospective cohort study

Acute respiratory distress syndrome is a heterogeneous pathophysiological process responsible for significant morbidity and mortality in pediatric intensive care patients. Diagnosis is defined by clinical characteristics that identify the syndrome after development. Subphenotyping patients at risk of progression to ARDS could provide the opportunity for therapeutic intervention. microRNAs, non-coding RNAs stable in circulation, are a promising biomarker candidate. We conducted a single-center prospective cohort study to evaluate random forest classification of microarray-quantified circulating microRNAs in critically ill pediatric patients. We additionally selected a sub-cohort for parallel metabolomics profiling as a pilot study for concurrent use of miRNAs and metabolites as circulating biomarkers. In 35 patients (n = 21 acute respiratory distress, n = 14 control) 15 microRNAs were differentially expressed. Unsupervised random forest classification accurately grouped ARDS and control patients with an area under the curve of 0.762, which was improved to 0.839 when subset to only patients with bacterial infection. Nine metabolites were differentially abundant between acute respiratory distress and control patients (n = 4, both groups) and abundance was highly correlated with miRNA expression. Random forest classification of microRNAs differentiated critically ill pediatric patients who developed acute respiratory distress relative to those who do not. The differential expression of microRNAs and metabolites provides a strong foundation for further work to validate their use as a prognostic biomarker.

Xiao-Chai-Hu Decoction Ameliorates Poly (I:C)-Induced Viral Pneumonia through Inhibiting Inflammatory Response and Modulating Serum Metabolism

Viral pneumonia is widespread, progresses rapidly, and has a high mortality rate. Developing safe and effective therapies to treat viral pneumonia can minimize risks to public health and alleviate pressures on the associated health systems. Xiao-Chai-Hu (XCH) decoction can be used in the treatment of viral pneumonia. However, the mechanisms of XCH on viral pneumonia remain unclear. In this study, poly (I:C) was used to establish a mouse model of viral pneumonia, and the therapeutic effects of XCH on viral pneumonia were assessed. Furthermore, we evaluated the effects of XCH on inflammatory response. Lastly, untargeted metabolomics were used to study the metabolic regulatory mechanisms of XCH on viral pneumonia model mice. Our results showed that XCH treatment decreased the wet/dry ratio in lung tissue, total protein concentration, and total cell count in bronchoalveolar lavage fluid (BALF). H&E staining indicated that XCH treatment alleviated the pathological changes in lung. Moreover, XCH treatment decreased the levels of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) and lowered the ratio of CD86⁺/CD206⁺ macrophages and CD11b⁺LY6G⁺ neutrophils in BALF. XCH treatment also decreased the myeloperoxidase (MPO) and reduced the phosphorylations of PI3K, AKT, and NF-κB p65 in lung. Serum untargeted metabolomics analysis showed that XCH treatment could affect 18 metabolites in serum such as creatine, hydroxyproline, cortisone, hydrocortisone, corticosterone, hypotaurine, and taurine. These metabolites were associated with arginine and proline metabolism, steroid hormone biosynthesis, and taurine and hypotaurine metabolism processes. In conclusion, our study demonstrated that treatment with XCH can ameliorate viral pneumonia and reduce inflammatory response in viral pneumonia. The mechanism of action of XCH in the treatment of viral pneumonia may be associated with inhibiting the activation of PI3K/AKT/NF-κB signaling pathway in lung and regulating arginine and proline metabolism, steroid hormone biosynthesis, and taurine and hypotaurine metabolism in serum.

Early taurine administration as a means for halting the cytokine storm progression in COVID-19 patients

Around the world, more than 6.2 million individuals have died as a result of coronavirus disease 2019 (COVID-19). According to a recent survey conducted among immunologists, epidemiologists, and virologists, this disease is expected to become endemic. This implies that the disease could have a continuous presence and/or normal frequency in the population. Pharmacological interventions to prevent infection, as well as to treat the patients at an early phase of illness to avoid hospitalization are essential additions to the vaccines. Taurine is known to inhibit the generation of all inflammatory mediators linked to the cytokine storm. It can also protect against lung injury by suppressing increased oxidants production and promoting the resolution of the inflammatory process. Neutrophil lactoferrin degranulation stimulated by taurine may have antiviral effects against SARS-CoV-2, limiting viral replication. It is hypothesized that if taurine is administered early in the onset of COVID-19 disease, it may stop the cytokine storm from progressing, lowering morbidity and mortality.

Dexmedetomidine protects against acute lung injury in mice via the DUSP1/MAPK/NF-κB axis by inhibiting miR-152-3p

OBJECTIVE

Acute lung injury (ALI) is a debilitating condition in clinics. Dexmedetomidine (Dex) is known for its anti-apoptotic and anti-inflammatory properties. This study attempted to investigate the protective mechanism of Dex in ALI mice.

METHODS

Mice were pretreated with Dex before model establishment by tracheal injection of lipopolysaccharide (LPS). Pulmonary function indexes and wet-to-dry (W/D) ratio were measured. Pulmonary pathological changes were observed through HE staining, CD31+-positive mouse pulmonary microvascular endothelial cells (MPMVECs) were counted through immunofluorescence staining, and apoptosis was detected through TUNEL staining. miR-152-3p mimic, sh-DUSP1, or p38 MAPK inhibitor was delivered into MPMVECs, followed by combined treatment of Dex and LPS. miR-152-3p expression, apoptosis, levels of apoptosis- and MAPK/NF-κB pathway-associated proteins, and inflammatory factors were measured through RT-qPCR, flow cytometry, Western blot, and ELISA. The binding relationship of miR-152-3p and DUSP1 was verified through bioinformatics software and dual-luciferase assay. ALI mouse model was established after injection of miR-152-3p antagomir.

RESULTS

Dex improved ALI mouse pulmonary function and mitigated injury in mice and MPMVECs. miR-125-3p overexpression or sh-DUSP1 partially abolished the protection of Dex on MPMVECs. miR-152-3p targeted DUSP1. sh-DUSP1 partially averted the protection of Dex on MPMVECs. Dex inhibited the activation of the MAPK/NF-κB pathway in MPMVECs mediated by LPS, which was partially reversed by sh-DUSP1. The p38 MAPK inhibitor SB203580 antagonized the protective effect of Dex on MPMVECs mediated by sh-DUSP1. Similarly, downregulation of miR-152-3p mitigated ALI via the DUSP1/MAPK/NF-κB axis in vivo.

CONCLUSION

Dex relieved ALI in mice via the DUSP1/MAPK/NF-κB axis by down-regulating miR-152-3p.

Dexmedetomidine modulates mitochondrial dynamics to protect against endotoxin-induced lung injury via the protein kinase C-ɑ/heme oxygenase-1 signaling pathway

BACKGROUND

Endotoxin-induced acute lung injury (ALI) has a high mortality rate, and there are limited effective treatment options available. The aim of the present study was to identify if dexmedetomidine could regulate mitochondrial fusion and fission through the protein kinase C (PKC)-α/heme oxygenase (HO)-1 pathway to protect against endotoxin-induced ALI.

MATERIALS AND METHODS

Dexmedetomidine was administered by intraperitoneal injection once daily for 3 days prior to induction of lung injury to mice. Mice in the PKC-α inhibitor group received dexmedetomidine by intraperitoneal injection 1 h after each chelerythrine injection, and lipopolysaccharide was injected 1 h after the last dose of dexmedetomidine. The lung wet/dry weight ratio, oxidative stress, inflammatory response, and expression levels of PKC-α, Nrf2, HO-1, Mfn1, Mfn2, OPA1, Drp1, and Fis1 were determined.

RESULTS

Dexmedetomidine administration attenuated lung oxidative stress, decreased inflammatory cytokines secretion, and downregulated the expression levels of Drp1 and Fis1. Moreover, dexmedetomidine increased levels of Mfn1, Mfn2, and OPA1, and alleviated endotoxin-induced lung injury. Administration of chelerythrine partially reversed the pneumoprotective effects of dexmedetomidine.

CONCLUSIONS

Dexmedetomidine may activate the PKC-ɑ/HO-1 pathway to increase the expression of Mfn1, Mfn2, and OPA1, while decreasing Drp1 and Fis1 expression, thereby reduce endotoxin-induced acute lung injury.

Taurine alleviates kidney injury in a thioacetamide rat model by mediating Nrf2/HO-1, NQO-1 and MAPK/ NF-κB signaling pathways

This study aimed to investigate the molecular mechanisms by which taurine exerts its reno-protective effects in thioacetamide (TAA)-induced kidney injury in rats. Rats received taurine (100 mg/kg daily, intraperitoneally) either from day 1 of TAA injection (250 mg/kg twice weekly for 6 weeks) or after 6 weeks of TAA administration. Taurine treatment, either concomitant or later as a therapy, restored kidney functions, reduced BUN, creatinine, MDA, and increased renal levels of SOD and reversed the increase of KIM-1 and NGAL caused by TAA. Taurine treatment also led to a significant rise in Nrf2, HO-1, and NQO-1 levels, with significant suppression of ERK 1/2, NF-κB, and TNFα gene expressions, and IL-18 and TNFα protein levels compared to those in TAA kidney-injured rats. Taurine exhibited reno-protective potential in TAA-induced kidney injury through its anti-oxidant and anti-inflammatory effects. Taurine anti-oxidant activity is accredited to its effect on Nrf-2 induction and subsequent activation of HO-1 and NQO-1. In addition, taurine exerts its anti-inflammatory effect via regulating NF-κB transcription and subsequent production of pro-inflammatory mediators via MAPK signaling regulation.

Dexmedetomidine Directs T Helper Cells toward Th1 Cell Differentiation via the STAT1-T-Bet Pathway

Dexmedetomidine is an α2 adrenergic receptor agonist that has been reported to modulate the polarization of CD4+ T cells. However, the underlying mechanisms by which dexmedetomidine induces T-helper 1 (Th1) cell differentiation remain poorly understood. The aim of this study was to explore the potential mechanisms through which dexmedetomidine can induce Th1 cell differentiation. Purified CD4+ T cells were stimulated with anti-CD3/anti-CD28 and then treated with dexmedetomidine. Flow cytometry analysis was adopted to measure the concentration of Th1 cells. Enzyme-linked immunosorbent assay (ELISA) and real-time quantitative polymerase chain reaction (qPCR) were performed to detect protein levels and mRNA expression, respectively, of IFN-γ and IL-4. Western blotting was used to determine the phosphorylation of signal transducer and activator of transcription 1 (STAT1) and T-bet expression. The Th1 cell subset and IFN-γ levels were elevated in the dexmedetomidine-induced CD4+ T cells. Dexmedetomidine enhanced the phosphorylation of STAT1 and the expression of T-bet in the CD4+ T cells. Atipamezole (an α2 adrenergic antagonist) and fludarabine (a STAT1 inhibitor) reversed the dexmedetomidine-induced Th1 cell differentiation. These results suggested that dexmedetomidine induced Th1 cell differentiation via the STAT1-T-bet signaling pathway.

Protective effect of taurine on sepsis‑induced lung injury via inhibiting the p38/MAPK signaling pathway

Sepsis, a leading cause of acute lung injury (ALI), is characterized by an overwhelming systemic inflammatory response and widespread organ injury, particularly in the lungs. Taurine, an intracellular free amino acid, has been used for the treatment of various diseases, including lung injury; however, the underlying mechanisms are unclear. The present study aimed to investigate the protective effect of taurine on septic ALI and the underlying mechanism. A septic ALI model was established by performing cecal ligation and puncture (CLP) surgery on Sprague Dawley rats. Following successful model establishment, rats were treated with taurine. The results of hematoxylin and eosin, respiratory function detection, malondialdehyde level and superoxide dismutase activity determination and ELSIA demonstrated that taurine significantly alleviated lung injury, restored respiratory function, reduced oxidation and decreased the concentrations of inflammatory factors in CLP‑induced septic ALI model rats. In addition, compared with that in the ALI group, western blotting results indicated that taurine ameliorated lung epithelial injury by significantly increasing the expression levels of lung epithelial markers, E‑cadherin and occludin. The western blotting results demonstrated that, compared with the control group, the p38/MAPK and NF‑κB signaling pathways were significantly activated in CLP‑induced septic ALI model rats, but taurine significantly suppressed ALI‑mediated signaling pathway activation. To investigate the mechanism underlying taurine in the treatment of septic ALI, CLP‑induced septic ALI model rats were treated with an antagonist of the p38/MAPK signaling pathway (SB203580). The effects of SB203580 on CLP‑induced septic ALI model rats were similar to those of taurine. SB203580 significantly attenuated sepsis‑induced lung injury and increases in IL‑1β and TNF‑α concentrations in the lung tissue. In addition, SB203580 promoted restoration of the injured lung tissue and respiratory function in CLP‑induced septic ALI model rats. The western blotting results indicated that SB203580 significantly decreased the ratios of phosphorylated (p)‑p38/p38 and p‑p65/065, and increased the protein expression levels of E‑cadherin and occludin compared with those in the ALI group. In summary, the present study demonstrated that taurine alleviated sepsis‑induced lung injury, which was associated with suppression of the inflammatory response and oxidative stress via inhibiting the p38/MAPK signaling pathway. Therefore, the p38/MAPK signaling pathway may serve as a potential therapeutic target for the treatment of sepsis‑induced ALI.

Dexmedetomidine promotes inflammation resolving through TGF-β1 secreted by F4/80+Ly6G+ macrophage

Dexmedetomidine (DEX) is a highly selective α2-adrenoceptor agonist, which can regulate inflammatory responses. However, whether DEX interferes with the inflammation resolving remains unclear. Here, we reported the effects of DEX on zymosan-induced generalized inflammation in mice during resolution. Mice were administered intraperitoneally with DEX after the initiation of sepsis. The resolution interval (Ri), a vital resolution indice, decreased from twelve hours to eight hours after the administration of DEX. The induction of peritoneal pro-inflammatory interleukin [IL] - 1β and tumour necrosis factor-α (TNF-α) appeared to be inhibited. Of interest, the anti-inflammatory transforming growth factor-β1 (TGF-β1) but not IL-10 levels were up-regulated at twenty-four hours in the DEX group along with 1.0 mg/mice zymosan A (ZyA) treatment. The expression levels of multiple genes related to protective immune processes and clearance functions were detected and revealed the same trends. DEX markedly increased the F4/80+Ly6G+ macrophage population. Additionally, the adequate apoptotic neutrophil clearance from injury after DEX installation could be reverse by opsonization or co-instillation of TGF-β1 neutralizing antibody in vivo, promoting the inflammation-resolution programs. In conclusion, DEX post-treatment, via the increase of F4/80+Ly6G+ macrophages, provokes further secretion of TGF-β1, leading to the attenuated cytokine storm and accelerated inflammation resolving.

Dexmedetomidine ameliorates endotoxin-induced acute lung injury in vivo and in vitro by preserving mitochondrial dynamic equilibrium through the HIF-1a/HO-1 signaling pathway

Increasing lines of evidence identified that dexmedetomidine (DEX) exerted protective effects against sepsis-stimulated acute lung injury via anti-inflammation, anti-oxidation and anti-apoptosis. However, the mechanisms remain unclear. Herein, we investigated whether DEX afforded lung protection by regulating the process of mitochondrial dynamics through the HIF-1a/HO-1 pathway in vivo and in vitro. Using C57BL/6J mice exposed to lipopolysaccharide, it was initially observed that preemptive administration of DEX (50μg/kg) alleviated lung pathologic injury, reduced oxidative stress indices (OSI), improved mitochondrial dysfunction, upregulated the expression of HIF-1α and HO-1, accompanied by shifting the dynamic course of mitochondria into fusion. Moreover, HO-1-knockout mice or HO-1 siRNA transfected NR8383 cells were pretreated with HIF-1α stabilizer DMOG and DEX to validate the effect of HIF-1a/HO-1 pathway on DEX-mediated mitochondrial dynamics in a model of endotoxin-induced lung injury. We found that pretreatment with DEX and DMOG distinctly relieved lung injury, decreased the levels of mitochondrial ROS and mtDNA, reduced OSI, increased nuclear accumulation of HIF-1a and HO-1 protein in wild type mice but not HO-1 KO mice. Similar observations were recapitulated in NC siRNA transfected NR8383 cells after LPS stimulation but not HO-1 siRNA transfected cells. Concertedly, DEX reversed the impaired mitochondrial morphology in LPS stimulated-wild type mice or NC siRNA transfected NR8383 cells, upregulated the expression of mitochondrial fusion protein, while downregulated the expression of fission protein in HIF-1a/HO-1 dependent pathway. Altogether, our data both in vivo and in vitro certified that DEX treatment ameliorated endotoxin-induced acute lung injury by preserving the dynamic equilibrium of mitochondrial fusion/fission through the regulation of HIF-1a/HO-1 signaling pathway.

Dexmedetomidine inhibits apoptosis of astrocytes induced by oxygen-glucose deprivation via targeting JAK/STAT3 signal pathway

OBJECTIVE

There is an increasing interest concerning the contribution of astrocytes to the intrinsic bioremediation of ischemic brain injury. The aim of this work was to disclose the effects and mechanism of dexmedetomidine (DEX) on the apoptosis of astrocytes under oxygen glucose deprivation (OGD) condition.

METHODS

Primary cultured astrocytes separated from Sprague-Dawley (SD) rats were subjected to OGD treatment. Astrocytes were transfected with si-JMJD3 or pcDNA3.1-JMJD3 and then treated with DEX or JAK/STAT inhibitor (WP1066) before cell apoptosis was detected by TUNEL apoptosis kit. Western blot was applied to assess the level of apoptosis-related proteins Caspase-3, Bax and Bcl-2. Astrocyte cell viability was assessed by measuring the lactate dehydrogenase (LDH) level using a LDH assay kit.

RESULTS

Astrocytes received OGD treatment had increased LDH and elevated apoptotic rate (P < 0.05). DEX could suppress OGD induced cytotoxic effect on astrocytes, as evidenced by decreased LDH release and suppressed cell apoptosis rate (P < 0.05). Meanwhile, DEX and WP1066 treatment were also found to inhibit the phosphorylation level of STAT1 and STAT3 (P < 0.05), indicating the DEX could suppress the activation of JAK/STAT signal pathway. JMJD3 overexpression in astrocytes could suppress the anti-apoptotic function of WP1066 in OGD treated astrocytes and hamper the protective effect of DEX in cell apoptosis (P < 0.05), suggesting that DEX and JAK/STAT signal pathway inhibits OGD induced apoptosis in astrocytes by down-regulating JMJD3.

CONCLUSION

DEX protects astrocytes against apoptosis via inhibiting JAK2/STAT3 signal pathway and downregulating JMJD3 expression in vitro.

Dexmedetomidine For The Treatment Of Acute Lung Injury: A Fact Or Fiction?

Dexmedetomidine has been widely used in the intensive care unit (ICU), with the primary aim to keep patients on an appropriate level of sedation. Both observational and randomized controlled trials have observed that the use of dexmedetomidine is associated with improved outcomes for mechanically ventilated patients [1]. In ICU patients receiving prolonged mechanical ventilation, dexmedetomidine was not inferior to other sedatives in maintaining sedation level, but was associated with shortened MV duration and improved ability to communicate pain [2]. MV is an important factor for delirium and dexmedetomidine was found to be associated with lower risk of delirium [3, 4]. Prophylactic low-dose dexmedetomidine is able to reduce the occurrence of delirium during the first 7 days after surgery for patients aged over 65 years who are admitted to the ICU after surgery [4]. Thus, the beneficial effect of might be explained by the reduction of delirium in the treated group. In fact, delirium can be considered as a type of acute organ dysfunction mediated via inflammatory response. There has been evidence that inflammatory biomarkers such as C-reactive protein was positively correlated with the occurrence of delirium [5].

Dexmedetomidine alleviated sepsis‑induced myocardial ferroptosis and septic heart injury

Cardiac dysfunction resulting from sepsis may cause significant morbidity and mortality, and ferroptosis plays a role in this pathology. Dexmedetomidine (Dex), a α2‑adrenergic receptor (α2‑AR) agonist exerts cardioprotective effects against septic heart dysfunction, but the exact mechanism is unknown. In the present study, sepsis was induced by cecal ligation and puncture (CLP) in male C57BL/6 mice. Dex and yohimbine hydrochloride (YOH), an α2‑AR inhibitor, were administered before inducing CLP. Then, 24 h after CLP, serum and heart tissue were collected to detect changes of troponin‑I (TN‑I), interleukin 6 (IL‑6), superoxide dismutase (SOD), malonaldehyde (MDA) and glutathione (GSH) levels, and iron release. Ferroptosis‑targeting proteins, apoptosis and inflammatory factors were assessed by western blotting or ELISA. It was found that, 24 h after CLP, TN‑I, a biomarker of myocardial injury, was significantly increased compared with the control group. Furthermore, the levels of MDA, 8‑hydroxy‑2'‑deoxyguanosine and the inflammatory factors IL‑6 and monocyte chemoattractant protein‑1 were also significantly increased. It was demonstrated that treatment with Dex reverted or attenuated these changes (CLP + Dex vs. CLP; P<0.05), but these protective effects of Dex were reversed by YOH. Moreover, CLP significantly decreased the protein expression levels of glutathione peroxidase 4 (GPX4), SOD and GSH. However, CLP increased expression levels of heme oxygenase‑1 (HO‑1), transferrin receptor, cleaved caspase 3, inducible nitric oxide synthase and gasdermin D, and iron concentrations. It was found that Dex reversed these changes, but YOH abrogated the protective effects of Dex (CLP + Dex + YOH vs. CLP + Dex; P<0.05). Therefore, the present results suggested that the attenuation of sepsis‑induced HO‑1 overexpression and iron concentration, and the reduction of ferroptosis via enhancing GPX4, may be the major mechanisms via which Dex alleviates sepsis‑induced myocardial cellular injury.

Dexmedetomidine inhibits the invasion, migration, and inflammation of rheumatoid arthritis fibroblast-like synoviocytes by reducing the expression of NLRC5

Rheumatoid arthritis (RA) is a chronic, autoimmune disease characterized by inflammatory synovitis, but its pathogenesis remains unclear. NLRC5 is a newly discovered member of the NLR family that is effective in regulating autoimmunity, inflammatory responses, and cell death processes. Dexmedetomidine (DEX) has been reported to have a variety of pharmacological effects, including anti-inflammatory and analgesic effects. However, the role of DEX in RA has not been explored. In adjuvant-induced arthritis (AA) rat models, DEX (10 μg/kg and 20 μg/kg) reduced the pathological score, the arthritis score, paw swelling volume, and the serum levels of IL-1β, IL-6, IL-17A, and TNF-α. Moreover, by using Western blot and real-time quantitative PCR (RT-qPCR), it was demonstrated that DEX can inhibit the expression of IL-1β, IL-6, MMP-3, MMP-9 and P-P65 in the synovial tissue of AA rats. In human rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs), DEX (250 nM and 500 nM) was found to inhibit the expression of IL-1β, IL-6, MMP-3, MMP-9, and P-P65 following stimulation with TNF-α. Moreover, DEX can inhibit the invasion and migration of RA-FLSs stimulated by TNF-α. Finally, the expression of NLRC5 in RA-FLSs and AA rat models was also reduced by DEX. After silencing NLRC5 in RA-FLSs, the expression of IL-1β, IL-6, MMP-3, MMP-9, and P-P65, as well as the invasion and migration of cells, were significantly reduced. These results indicate that DEX inhibits the invasion, migration, and inflammation of RA-FLSs by reducing the expression of NLRC5 and inhibiting the NF-κB activation.

Mitochondrial Coenzyme Q Protects Sepsis-Induced Acute Lung Injury by Activating PI3K/Akt/GSK-3β/mTOR Pathway in Rats

The aim of our study was to assess the effects of mitochondrial coenzyme Q (MitoQ) on sepsis-induced acute lung injury (ALI) and investigate its possible mechanisms. The cecal ligation and puncture (CLP) method was used to establish a septic ALI model. Rats were randomly divided into Con group, CLP group, MitoQ group, and MitoQ + LY294002 group. The survival rate of the rats was recorded, and the survival rate curve was plotted. Moreover, the ratio of wet/dry weight (W/D) in lung tissue was measured. The activity of myeloperoxidase (MPO) was measured by using the MPO colorimetric activity assay kit. The levels of high-mobility group box 1 (HMGB1) and interleukin-6 (IL-6), macrophage inflammatory protein 2 (MIP2), and keratinocyte chemoattractant (KC) were analyzed by ELISA. The histopathological changes were measured by HE staining, and the lung injury was scored. TUNEL assay was applied to detect the apoptotic cells in lung tissue. The protein expressions were detected by western blot. MitoQ increased the survival rate and alleviated pulmonary edema in septic ALI rats. In addition, MitoQ inhibited the MPO activity and decreased the levels of HMGB1 and IL-6. After treatment with MitoQ, alveolar wall edema, inflammatory cell infiltration, and red blood cell exudation were relieved. MitoQ inhibited cell apoptosis in lung tissue of septic ALI rats. Meanwhile, MitoQ treatment remarkedly increased the expression of p-Akt, p-GSK-3β, and p-mTOR but decreased Bax, caspase-3, caspase-9, Beclin-1, and LC-3II/LC-3I. The effects of MitoQ were significantly reversed by the PI3K inhibitor (LY294002). Our study demonstrated that MitoQ could protect sepsis-induced acute lung injury by activating the PI3K/Akt/GSK-3β/mTOR pathway in rats.

The protective effects of angiotensin-converting enzyme inhibitor against cecal ligation and puncture-induced sepsis via oxidative stress and inflammation

AIMS

Sepsis is a severe public health problem affecting millions of individuals, with global mortality rates caused by lower respiratory tract infections are approximately 2.38 million people a year die from respiratory failure caused by infection. Although ACE is known to contribute to damage in septicemia, the pathophysiological mechanisms of sepsis remain unclear. While mortality can be significantly reduced through effective and sensitive antibiotic therapy, antibiotic resistance restricts the use of these drugs, and the investigation of novel agents and targets is therefore essential. Our aim was to determine whether Perindopril (PER) has anti-inflammatory and antioxidant capable of preventing these adverse conditions resulting in injury in previous studies.

MAIN METHODS

Sprague Dawley rats were randomly assigned into the control group, received oral saline solution alone for four days. the cecal ligation and puncture (CLP) group, underwent only cecal ligation and puncture induced sepsis, while the CLP + PER (2 mg/kg) underwent cecal ligation and puncture-induced sepsis together with oral administration of 2 mg/kg PER for four days before induction of sepsis.

KEY FINDINGS

Malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), Caspase-3 and nuclear factor kappa B (NF-kβ/p65) levels increased in the CLP group. On the other hand, PER (2 mg/kg) oral administration to septic rats decreased MDA, TNF-α and increase glutathione (GSH) in the lung tissue. In addition, PER administration also decreased the lung tissue NF-κB and Caspase-3 immunopositivity against sepsis.

SIGNIFICANCE

PER treatment may represent a promising means of preventing sepsis-induced lung injury via antioxidant and anti-inflammation effects.

Dexmedetomidine effects in different experimental sepsis in vivo models

Sepsis is a major cause of death and the most common cause of death among critically ill, non-ICU patients. Dexmedetomidine (DEX), an <alpha>₂ adrenergic receptor agonist, presents sympatholytic action in certain parts of the brain with anxiolytic, sedative, and pain killing effects. Additionally, through the activation of <alpha>₇ nicotinic acetylcholine receptor receptors, DEX reduces cytokine transcription and inhibits inflammation, rendering it beneficial during septic conditions. Moreover, there is a lot of interest in designing experimental sepsis models, where the administration of DEX is evaluated for its impact on multiple systems. This review focuses on experimental studies published between 1999 to March 2019 that were using DEX administration in sepsis in vivo models. From these, 36 articles were selected and summarized. Overall results show evidence that DEX may decrease mortality and inhibit inflammation, as it enhances the activity of the immune system while reducing its systemic reaction and lowering cytokine concentrations. Moreover DEX succeeds to alleviate heart injury during sepsis, acting beneficially for microcirculation and shows a neuroprotective role by inhibiting apoptotic pathways. In addition, DEX appears to have a protective role for liver and spleen as well as a beneficial role for the function of lungs and kidneys as it reduces sepsis-induced injuries and apoptosis in intra-abdominal experimental sepsis models.

Retracted Article: A high-throughput metabolomics strategy for discovering the influence of differential metabolites and metabolic pathways of huaxian capsules on sepsis-associated Qi deficiency and blood stasis syndrome

High-throughput metabolomics can be used to investigate the therapeutic targets and metabolic mechanisms of traditional Chinese medicine formulae.