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

Dual-responsive nanoparticles targeting ACE-II senescence for therapeutic mitigation of acute lung injury

Acute lung injury (ALI) is a life-threatening condition characterized by severe pulmonary dysfunction, with alveolar type II epithelial cell (ACE-II) senescence playing a pivotal role in its progression. In this study, we developed pH/reactive oxygen species (ROS) dual-responsive nanoparticles (GNPsanti-SP-C) for the targeted delivery of Growth Differentiation Factor 15 (GDF15) to counteract ACE-II senescence. These nanoparticles (NPs) effectively activate the AMP-activated protein kinase (AMPK)/Sirtuin 1 (SIRT1) signaling pathway, inducing the mitochondrial unfolded protein response (UPRmt) and reversing senescence-associated cellular dysfunction. GNPsanti-SP-C were systematically engineered and demonstrated robust pH/ROS sensitivity, efficient GDF15 release, and precise ACE-II targeting. In lipopolysaccharide (LPS)-induced ALI mouse model, GNPsanti-SP-C treatment significantly mitigated lung injury, reduced inflammatory responses, and enhanced pulmonary function, as evidenced by decreased inflammatory markers, lung edema, and improved histopathology. Single-cell transcriptomic and proteomic analyses revealed increased ACE-II cell populations, reduced expression of senescence markers, and upregulation of AMPK/SIRT1 signaling. In vitro studies further demonstrated that UPRmt activation is associated with the NPs' therapeutic effects, suggesting a potential role in their mechanism of action. These findings demonstrate the potential of GDF15-loaded dual-responsive NPs as an innovative strategy to address cellular senescence and alleviate ALI-associated pulmonary damage.

Dexmedetomidine improve lung inflammation by regulating autophagy and apoptosis of CD4+ T cell via AMPK/mTOR signaling

OBJECTIVES

To investigate the protective effect and potential mechanism of dexmedetomidine (Dex) in acute lung injury (ALI).

MATERIALS AND METHODS

C57BL/6 mice and EL-4 cells were used for in vivo and in vitro studies, respectively. Cecal ligation and puncture (CLP) method was used to prepare an acute lung injury model. After dexmedetomidine intervention, tissue and cell samples were collected to evaluate and measure the severity of lung damage, the proportion of Treg cells, the expression of autophagy-related protein levels and AMPK/mTOR pathways.

RESULTS

Dex reduced lung damage, and IL-17a, MPO positive cells in the lung, decreased the levels of pro-inflammatory cytokines, and restrain autophagy and apoptosis via the activation of the AMPK/mTOR pathway and increase of the proportion of Tregs.

CONCLUSIONS

Dex can inhibit the levels of autophagy and apoptosis, increase the proportion of Treg cells, and reduce CLP induced acute lung injury through regulating AKMP/MTOR pathway.

Characterization of lactylation-based phenotypes and molecular biomarkers in sepsis-associated acute respiratory distress syndrome

Sepsis-associated acute respiratory distress syndrome (ARDS) is a heterogeneous disease with high morbidity and mortality. Lactylation plays a crucial role in sepsis and sepsis-induced lung injury. This study aimed to identify distinct lactylation-based phenotypes in patients with sepsis-associated ARDS and determine relevant molecular biomarkers. We analyzed blood transcriptome and clinical data from patients with sepsis-associated ARDS and calculated the lactylation activity. KEGG pathway analysis, drug sensitivity prediction, and immune cell infiltration analysis were performed. Candidate molecular biomarkers were identified by intersecting the feature genes extracted from four machine learning models. Lactylation activity showed significant heterogeneity among patients with sepsis-associated ARDS, which enabled the classification into low- and high-lactylation activity phenotypes. Patients with high-lactylation experienced longer hospital stays and higher mortality rates, as well as distinct signaling pathways, drug responses, and circulating immune cell abundances. Six key markers (ALDOB, CCT5, EP300, PFKP, PPIA, and SIRT1) were identified to differentiate the two lactylation activity phenotypes, all significantly correlated with circulating immune cell populations. This study revealed significant heterogeneity in lactylation activity phenotypes among patients with sepsis-associated ARDS and identified potential biomarkers to facilitate the application of these phenotypes in clinical practice.

Advances in acute respiratory distress syndrome: focusing on heterogeneity, pathophysiology, and therapeutic strategies

In recent years, the incidence of acute respiratory distress syndrome (ARDS) has been gradually increasing. Despite advances in supportive care, ARDS remains a significant cause of morbidity and mortality in critically ill patients. ARDS is characterized by acute hypoxaemic respiratory failure with diffuse pulmonary inflammation and bilateral edema due to excessive alveolocapillary permeability in patients with non-cardiogenic pulmonary diseases. Over the past seven decades, our understanding of the pathology and clinical characteristics of ARDS has evolved significantly, yet it remains an area of active research and discovery. ARDS is highly heterogeneous, including diverse pathological causes, clinical presentations, and treatment responses, presenting a significant challenge for clinicians and researchers. In this review, we comprehensively discuss the latest advancements in ARDS research, focusing on its heterogeneity, pathophysiological mechanisms, and emerging therapeutic approaches, such as cellular therapy, immunotherapy, and targeted therapy. Moreover, we also examine the pathological characteristics of COVID-19-related ARDS and discuss the corresponding therapeutic approaches. In the face of challenges posed by ARDS heterogeneity, recent advancements offer hope for improved patient outcomes. Further research is essential to translate these findings into effective clinical interventions and personalized treatment approaches for ARDS, ultimately leading to better outcomes for patients suffering from ARDS.

Therapeutic Effects of TN13 Peptide on Acute Respiratory Distress Syndrome and Sepsis Models In Vivo

Background/Objectives: Regulation of acute inflammatory responses is crucial for host mortality and morbidity induced by pathogens. The pathogenesis of acute respiratory distress syndrome (ARDS) and sepsis are associated with systemic inflammation. p38 MAPK is a crucial regulator of inflammatory responses and is a potential target for acute inflammatory diseases, including ARDS and sepsis. We investigated the therapeutic effects of the TAT-TN13 peptide (TN13) on severe inflammatory diseases, including ARDS and sepsis, in vivo. Methods: To establish the ARDS model, C57BL/6 mice were intranasally (i.n.) administered lipopolysaccharide (LPS; 5 mg/kg, 40 µL) to induce lung inflammation. As a positive control, dexamethasone (DEX; 0.2 mg/kg) was administered intraperitoneally (i.n.) 1 h post-LPS exposure. In the experimental groups, TN13 was administered intranasally (i.n.) at doses of 2.5 mg or 5 mg/kg at the same time point. In the LPS-induced sepsis model, mice received an intraperitoneal injection of LPS (20 mg/kg) to induce systemic inflammation. TN13 (25 mg/kg, i.p.) was administered 1 h after LPS treatment. Control mice received phosphate-buffered saline (PBS). Lung histopathology, inflammatory cell infiltration, cytokine levels, and survival rates were assessed to evaluate TN13 efficacy. Results: TN13 significantly reduced inflammatory cell recruitment and cytokine production in the lungs, thereby mitigating LPS-induced ARDS. In the sepsis model, TN13 treatment improved survival rates by suppressing inflammatory responses. Mechanistically, TN13 exerted its effects by inhibiting the p38 MAPK/NF-κB signaling pathway. Conclusions: These results collectively suggested that TN13 could be an effective treatment option for severe inflammatory diseases.

Intranasal Atomized Dexmedetomidine in Combination With Intranasal Atomized Butorphanol for Dressing Change Sedation and Analgesia in Adult Burn Patients: A Randomized Clinical Trial

We aimed to evaluate the efficacy of the intranasal atomized dexmedetomidine (IAD) + intranasal atomized butorphanol (IAB) combination therapy on adult patients with burns undergoing dressing changes. Herein, 46 adult patients with burns were enrolled and randomly divided into 2 groups: dexmedetomidine-butorphanol (DB) and saline-butorphanol, treated with atomized dexmedetomidine + butorphanol and saline + butorphanol, respectively. The primary outcomes were the Ramsay Sedation Scale (RSS) and the Visual Analog Scale (VAS) scores. The secondary outcomes were mean blood pressure (MBP), heart rate, respiratory rate (RR), peripheral blood oxygen saturation (SpO2), total butorphanol consumption, and adverse effects. The 2 groups were comparable in age, sex, weight, and total burn surface area. During dressing changes, the DB group exhibited significantly lower RSS levels (P < .05). Besides, the 2 groups showed no significant differences in VAS scores across all measurement time points. Notably, the DB group exhibited decreased MBP at the beginning of the operation (P < .0001), 10 min after (P < .0001), and 20 min after (P = .0205). Heart rate decreased significantly at the beginning (P = .0005) and 10 min after (P = .0088) in the DB group. Furthermore, the 2 groups showed no significant differences in RR and SpO2 levels. In addition, the rescue butorphanol dose was lower in the DB group (P < .001). Finally, dizziness and nausea incidences were significantly lower in the DB group (P < .05). In conclusion, besides its hemodynamic adverse reactions, the IAD + IAB combination therapy exerted a better sedation effect in adult patients with burns than IAB treatment alone.

SIRT1 in acute lung injury: unraveling its pleiotropic functions and therapeutic development prospects

Acute lung injury (ALI) is a continuum of lung changes caused by multiple lung injuries, often associated with severe complications and even death. In ALI, macrophages, alveolar epithelial cells and vascular endothelial cells in the lung are damaged to varying degrees and their function is impaired. Research in recent years has focused on the use of SIRT1 for the treatment of ALI. In this paper, we reviewed the role of SIRT1 in ALI in terms of its cellular and molecular mechanism, targeting of SIRT1 by non-coding RNAs and drug components, as well as pointing out the value of SIRT1 for clinical diagnosis and prognosis. Based on the current literature, SIRT1 exhibits diverse functionalities and possesses significant therapeutic potential. Targeting SIRT1 may provide new therapeutic ideas for the treatment of ALI.

Advancements in omics technologies: Molecular mechanisms of acute lung injury and acute respiratory distress syndrome (Review)

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is an inflammatory response arising from lung and systemic injury with diverse causes and associated with high rates of morbidity and mortality. To date, no fully effective pharmacological therapies have been established and the relevant underlying mechanisms warrant elucidation, which may be facilitated by multi‑omics technology. The present review summarizes the application of multi‑omics technology in identifying novel diagnostic markers and therapeutic strategies of ALI/ARDS as well as its pathogenesis.

IL-27 regulates macrophage ferroptosis by inhibiting the Nrf2/HO1 signaling pathway in sepsis-induced ARDS

OBJECTIVES

Acute respiratory distress syndrome (ARDS) is a clinical syndrome characterized by high morbidity and mortality rates. Sepsis-induced ARDS involves excessive inflammatory responses, which are modulated by macrophages. This study aimed to elucidate the effect of Recombinant Mouse IL-27 Protein on macrophage ferroptosis and polarization, as well as its impact on sepsis-induced ARDS.

METHODS

A cecal ligation and puncture (CLP)-induced sepsis model was established using wild-type (WT) or IL27R-/- mice. Then, the mice were randomly divided into 4 groups: a control group, a CLP group, an IL-27 + CLP combination group, and an IL-27, CLP, and Oltipraz combination group. RAW 264.7 cells and BMDMs were used to further determine the role and mechanism of IL-27 in vitro.

RESULTS

In vitro, IL-27 alone did not alter the expression of proteins linked to the ferroptosis pathway or macrophage polarization. Contrastingly, the combination of IL-27 with LPS further amplified LPS-induced alterations in the ferroptosis pathway, thereby promoting macrophage M1 polarization and inhibiting M2 polarization. Additionally, IL-27 + LPS increased ROS levels in macrophages. A sepsis-induced ARDS mouse model was then established via CLP. In vivo, IL-27 exacerbated CLP-induced lung injury in WT mice. Additionally, it decreased the expression levels of ferroptosis-related proteins (Nrf2, HO-1, GPX4) and increased those of Ptgs2 in the lung tissue of septic mice. Besides, GSH and SOD levels in lung tissue were also reduced. Moreover, IL-27 also promoted M1 polarization and inhibited M2 polarization in macrophages. In IL27R-/- mice, the effects of IL-27 were abrogated. Oltipraz inhibited IL-27-induced changes by up-regulating Nrf2 expression. Overall, this present study demonstrated that the combination of IL-27 and LPS-induced macrophage ferroptosis, promoted macrophage M1 polarization, and inhibited M2 polarization by inhibiting the Nrf2/HO-1 pathway.

CONCLUSION

Oltipraz may alleviate ARDS-related lung injury by up-regulating Nrf2 expression and concurrently inhibiting macrophage ferroptosis.

Effect of Multidimensional Integrated Lung Protection Measures in Elderly Patients With Fragile Lungs or Combined Lung Dysfunction by Regulating AMPK/SIRT1 Pathway

Fragile lungs or lung dysfunction can significantly impact a patient's quality of life. Currently, no specific treatment exists to prevent lung dysfunction in elderly patients. The detailed mechanism of fragile lungs or lung dysfunction in elderly patients remains elusive, and this study aimed to clarify it. General data and blood specimens were obtained from patients with fragile lungs or lung dysfunction. The mice were exposed to cigarette smoke using a smoking apparatus to induce fragile lungs or lung dysfunction mice model. Blood samples and lung tissues were collected from all groups for further testing. haematoxylin-eosin (HE) staining, immunofluorescence, Western blot, flow cytometry and quantitative reverse transcriptase PCR (qRT-PCR) were used to elucidate the molecular mechanisms of multidimensional integrated lung protection measures (MILPM) in fragile lungs or lung dysfunction mice by targeting the AMP-activated protein kinase (AMPK)/Sirtuin 1 (SIRT1) pathway. The results indicated that upregulation of the AMPK/SIRT1 signalling pathway accelerates the fragile lungs or lung dysfunction process, whereas downregulation of the AMPK/SIRT1 signalling pathway can prevent it. Similarly, the change of forced vital capacity (FVC), total lung capacity (TLC) levels is associated with the fragile lungs or lung dysfunction process, whereas reducing their levels can serve as a preventative method against fragile lungs or lung dysfunction development. Upregulation of the AMPK/SIRT1 pathway can accelerate the process of fragile lungs or lung dysfunction.

Dexmedetomidine Regulates Macrophage Phenotype Remodeling Through AMPK/SIRT1 to Alleviate Inflammatory Mediators and Lung Injury

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is associated with high morbidity and mortality in the intensive care unit (ICU) and can cause excessive inflammation. Dexmedetomidine (DEX) is a drug that exerts anti-inflammatory effects. Identifying the anti-inflammatory mechanism of DEX in the context of ALI/ARDS possesses potential significance for the prevention and treatment of ARDS. In this study, DEX was used to treat mouse models of cecal ligation and puncture (CLP) and lipopolysaccharide (LPS)-stimulated cells. Immunofluorescence, western blot analysis, and flow cytometry were used to detect macrophage phenotypic markers in mice, and western blot analysis, real-time qPCR (RT-qPCR), ELISA, and immunofluorescence were used to detect macrophage phenotype markers in RAW264.7 cells. Flow cytometry was used to detect phenotypic markers of bone marrow-derived macrophages (BMDM). Culture medium collected from macrophages was used to cultivate human non-small cell adenocarcinoma epithelial cells (A549) to detect their aquaporins 1 (AQP1) expression and apoptosis status. Western blot analysis was used to detect the activation of the AMP-activated protein kinase (AMPK)/sirtuin 1(SIRT1) signaling pathway both in vivo and in vitro. The regulatory effect of DEX on macrophage phenotype remodeling was detected by knocking down AMPK expression in cells using AMPK shRNA. The results showed that in both in vivo and in vitro experiments, DEX downregulated the expression of M1 markers (tumor necrosis factor-α [TNF-α], nitric oxide synthase [iNOS], and cluster of differentiation [CD]-86) and upregulated the expression of M2 markers (arginase-1 [ARG-1], interleukin [IL]-10, and CD206) in macrophages. The culture medium of macrophages treated with DEX alleviated the edema and apoptosis of A549 cells. DEX activates the AMPK/SIRT1 signaling pathway in macrophages. After AMPK knockdown, the ability of DEX to regulate macrophage phenotype remodeling decreased. Together, this study suggests that DEX regulates macrophage phenotype remodeling by activating the AMPK/SIRT1 pathway, thereby reducing ALI/ARDS.

Novel Therapeutic Target for ALI/ARDS: Forkhead Box Transcription Factors

ALI/ARDS can be a pulmonary manifestation of a systemic inflammatory response or a result of overexpression of the body's normal inflammatory response involving various effector cells, cytokines, and inflammatory mediators, which regulate the body's immune response through different signalling pathways. Forkhead box transcription factors are evolutionarily conserved transcription factors that play a crucial role in various cellular processes, such as cell cycle progression, proliferation, differentiation, migration, metabolism, and DNA damage response. Transcription factors control protein synthesis by regulating gene transcription levels, resulting in diverse biological outcomes. The Fox family plays a role in activating or inhibiting the expression of various molecules related to ALI/ARDS through phosphorylation, acetylation/deacetylation, and control of multiple signalling pathways. An in-depth analysis of the integrated Fox family's role in ALI/ARDS can aid in the development of potential diagnostic and therapeutic targets for the condition.

Toll-like receptor 4 (TLR4) deficiency impedes Toxoplasma gondii excreted-secreted antigens (ESA)-induced abortion

INTRODUCTION

Toxoplasma gondii is an opportunistic intracellular parasite that is a major pathogenic factor in miscarriage, especially when it occurs early in pregnancy. We have previously demonstrated that the regulation of forkhead box transcription factor (Foxp3) is associated with abortion in early pregnancy caused by excretory-secretory antigen (ESA) of strain China 1. We aimed to reveal the underlying mechanism of miscarriage caused by ESA.

METHODS

A TLR4-/- pregnant mouse model was successfully constructed. Pregnant mice at gestational day 5 (G5) were injected with ESA. All animals were sacrificed on G13, pregnancy outcomes were observed, and abortion rates were calculated. Placental status observed by Hematoxylin-eosin staining; gene expression was measured by IHC; flow cytometry analysis was used to determine the number and function of regulatory T cells. In EL4 cells, real-time PCR and Western blot were used to evaluate gene expression and cytokines assay.

RESULTS

In vivo studies revealed that ESA injection caused 83% abortion in pregnant mice but only 35% abortion in TLR4-/- pregnant mice. In addition, ESA attenuated the number and function of regulatory T cells, further suppressed Foxp3, FOXO1 levels, and upregulated CD127 expression. TLR4-/- mice partially reversed this inhibitory effect on regulatory T cells. Furthermore, in vitro studies revealed that ESA inhibited TLR4/NF-κB signaling pathway expression and that TLR4 agonists significantly restored the ESA-induced decrease in Foxp3.

DISCUSSION

These findings suggest that ESA suppresses Foxp3 expression by blocking TLR4/NF-κB signaling, resulting in miscarriage. More importantly, the results indicated that miscarriage caused by ESA is TLR4 dependent.

Mapping Theme Trends and Research Frontiers in Dexmedetomidine Over Past Decade: A Bibliometric Analysis

Background

Dexmedetomidine, an α2-adrenergic receptor (α2-AR) agonist, is extensively used in clinical and animal studies owing to its sedative, analgesic, and anxiolytic effects. The diverse range of research domains associated with dexmedetomidine poses challenges in defining pivotal research directions. Therefore, this study aimed to conduct a qualitative and quantitative bibliometric study in the field of dexmedetomidine over the past decade to establish current research trends and emerging frontiers.

Methods

Relevant publications in the field of dexmedetomidine between 2014 and 2023 were extracted from the Web of Science Core Collection database. The bibliometric analysis, incorporating statistical and visual analyses, was conducted using CiteSpace (6.1.R6) and R (4.3.1).

Results

The present study encompassed a total of 5,482 publications, exhibiting a consistent upward trend over the past decade. The United States and its institutions had the highest centrality. Ji, Fuhai, and Ebert, Thomas J. were identified as the most productive author and the most cited author, respectively. As anticipated, the most cited journal was Anesthesiology. Moreover, cluster analysis of cited references and co-occurrence of keywords revealed that recent studies were primarily focused on sedation, delirium, and opioid-free anesthesia. Finally, a timeline view of keywords clusters and keywords burst demonstrated that primary research frontiers were stress response, neuroinflammation, delirium, opioid-free anesthesia, peripheral nerve block, and complications.

Conclusion

Current research trends and directions are focused on sedation, delirium, and opioid-free anesthesia, as evidenced by our results. The frontier of future research is anticipated to encompass basic investigations into dexmedetomidine, including stress response and neuroinflammation, as well as clinical studies focusing on delirium, opioid-free anesthesia, peripheral nerve block, and associated complications.

Exogenous modification of EL-4 T cell extracellular vesicles with miR-155 induce macrophage into M1-type polarization

Extracellular vesicles (EVs) show promising potential to be used as therapeutics, disease biomarkers, and drug delivery vehicles. We aimed to modify EVs with miR-155 to modulate macrophage immune response that can be potentially used against infectious diseases. Primarily, we characterized T cells (EL-4) EVs by several standardized techniques and confirmed that the EVs could be used for experimental approaches. The bioactivities of the isolated EVs were confirmed by the uptake assessment, and the results showed that target cells can successfully uptake EVs. To standardize the loading protocol by electroporation for effective biological functionality, we chose fluorescently labelled miR-155 mimics because of its important roles in the immune regulations to upload them into EVs. The loading procedure showed that the dosage of 1 µg of miRNA mimics can be efficiently loaded to the EVs at 100 V, further confirmed by flow cytometry. The functional assay by incubating these modified EVs (mEVs) with in vitro cultured cells led to an increased abundance of miR-155 and decreased the expressions of its target genes such as TSHZ3, Jarid2, ZFP652, and WWC1. Further evaluation indicated that these mEVs induced M1-type macrophage polarization with increased TNF-α, IL-6, IL-1β, and iNOS expression. The bioavailability analysis revealed that mEVs could be detected in tissues of the livers. Overall, our study demonstrated that EVs can be engineered with miR-155 of interest to modulate the immune response that may have implications against infectious diseases.

Progranulin promotes regulatory T cells plasticity by mitochondrial metabolism through AMPK/PGC-1α pathway in ARDS

As the aging population increases, the focus on elderly patients with acute respiratory distress syndrome (ARDS) is also increasing. In this article, we found progranulin (PGRN) differential expression in ARDS patients and healthy controls, even in young and old ARDS patients. Its expression strongly correlates with several cytokines in both young and elderly ARDS patients. PGRN has comparable therapeutic effects in young and elderly mice with lipopolysaccharide-induced acute lung injury, manifesting as lung injury, apoptosis, inflammation, and regulatory T cells (Tregs) differentiation. Considering that Tregs differentiation relies on metabolic reprogramming, we discovered that Tregs differentiation was mediated by mitochondrial function, especially in the aged population. Furthermore, we demonstrated that PGRN alleviated the mitochondrial damage during Tregs differentiation through the AMPK/PGC-1α pathway in T cells. Collectively, PGRN may regulate mitochondria function to promote Tregs differentiation through the AMPK/PGC-1α pathway to improve ARDS.

Targeting immunometabolism against acute lung injury

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are life-threatening conditions triggered by multiple intra- and extra-pulmonary injury factors, characterized by complicated molecular mechanisms and high mortality. Great strides have been made in the field of immunometabolism to clarify the interplay between intracellular metabolism and immune function in the past few years. Emerging evidence unveils the crucial roles of immunometabolism in inflammatory response and ALI. During ALI, both macrophages and lymphocytes undergo robust metabolic reprogramming and discrete epigenetic changes after activated. Apart from providing ATP and biosynthetic precursors, these metabolic cellular reactions and processes in lung also regulate inflammation and immunity.In fact, metabolic reprogramming involving glucose metabolism and fatty acidoxidation (FAO) acts as a double-edged sword in inflammatory response, which not only drives inflammasome activation but also elicits anti-inflammatory response. Additionally, the features and roles of metabolic reprogramming in different immune cells are not exactly the same. Here, we outline the evidence implicating how adverse factors shape immunometabolism in differentiation types of immune cells during ALI and summarize key proteins associated with energy expenditure and metabolic reprogramming. Finally, novel therapeutic targets in metabolic intermediates and enzymes together with current challenges in immunometabolism against ALI were discussed.