Activation of M1 macrophages plays a critical role in the initiation of acute lung injury

Integration of microbiomics, metabolomics, and transcriptomics reveals the therapeutic mechanism underlying Fuzheng-Qushi decoction for the treatment of lipopolysaccharide-induced lung injury in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Fuzheng-Qushi decoction (FZQS) is a practical Chinese herbal formula for relieving cough and fever. Therefore, the action and specific molecular mechanism of FZQS in the treatment of lung injury with cough and fever as the main symptoms need to be further investigated.

AIMS OF THE STUDY

To elucidate the protective effects of FZQS against lung injury in mice and reveal its potential targets and key biological pathways for the treatment of lung injury based on transcriptomics, microbiomics, and untargeted metabolomics analyses.

MATERIALS AND METHODS

Lipopolysaccharide (LPS) was used to induce a mouse model of lung injury, followed by the administration of FZQS. ELISA was used to detect IL-1β, IL-6, IL-17A, IL-4, IL-10, and TNF-α, in mouse lung tissues. Macrophage polarization and neutrophil activation were measured by flow cytometry. RNA sequencing (RNA-seq) was applied to screen for differentially expressed genes (DEGs) in lung tissues. RT-qPCR and Western blot assays were utilized to validate key DEGs and target proteins in lung tissues. 16S rRNA sequencing was employed to characterize the gut microbiota of mice. Metabolites in the gut were analyzed using untargeted metabolomics.

RESULTS

FZQS treatment significantly ameliorated lung histopathological damage, decreased pro-inflammatory cytokine levels, and increased anti-inflammatory cytokine levels. M1 macrophage levels in the peripheral blood decreased, M2 macrophage levels increased, and activated neutrophils were inhibited in mice with LPS-induced lung injury. Importantly, transcriptomic analysis showed that FZQS downregulated macrophage and neutrophil activation and migration and adhesion pathways by reversing 51 DEGs, which was further confirmed by RT-qPCR and Western blot analysis. In addition, FZQS modulated the dysbiosis of the gut microbiota by reversing the abundance of Corynebacterium, Facklamia, Staphylococcus, Paenalcaligenes, Lachnoclostridium, norank_f_Muribaculaceae, and unclassified_f_Lachnospiraceae. Meanwhile, metabolomics analysis revealed that FZQS significantly regulated tryptophan metabolism by reducing the levels of 3-Indoleacetonitrile and 5-Hydroxykynurenine.

CONCLUSION

FZQS effectively ameliorated LPS-induced lung injury by inhibiting the activation, migration, and adhesion of macrophages and neutrophils and modulating gut microbiota and its metabolites.

Deciphering the performance of macrophages in tumour microenvironment: a call for precision immunotherapy

Macrophages infiltrating tumour tissues or residing in the microenvironment of solid tumours are known as tumour-associated macrophages (TAMs). These specialized immune cells play crucial roles in tumour growth, angiogenesis, immune regulation, metastasis, and chemoresistance. TAMs encompass various subpopulations, primarily classified into M1 and M2 subtypes based on their differentiation and activities. M1 macrophages, characterized by a pro-inflammatory phenotype, exert anti-tumoural effects, while M2 macrophages, with an anti-inflammatory phenotype, function as protumoural regulators. These highly versatile cells respond to stimuli from tumour cells and other constituents within the tumour microenvironment (TME), such as growth factors, cytokines, chemokines, and enzymes. These stimuli induce their polarization towards one phenotype or another, leading to complex interactions with TME components and influencing both pro-tumour and anti-tumour processes.This review comprehensively and deeply covers the literature on macrophages, their origin and function as well as the intricate interplay between macrophages and the TME, influencing the dual nature of TAMs in promoting both pro- and anti-tumour processes. Moreover, the review delves into the primary pathways implicated in macrophage polarization, examining the diverse stimuli that regulate this process. These stimuli play a crucial role in shaping the phenotype and functions of macrophages. In addition, the advantages and limitations of current macrophage based clinical interventions are reviewed, including enhancing TAM phagocytosis, inducing TAM exhaustion, inhibiting TAM recruitment, and polarizing TAMs towards an M1-like phenotype. In conclusion, while the treatment strategies targeting macrophages in precision medicine show promise, overcoming several obstacles is still necessary to achieve an accessible and efficient immunotherapy.

Agent-based model demonstrates the impact of nonlinear, complex interactions between cytokinces on muscle regeneration

Muscle regeneration is a complex process due to dynamic and multiscale biochemical and cellular interactions, making it difficult to identify microenvironmental conditions that are beneficial to muscle recovery from injury using experimental approaches alone. To understand the degree to which individual cellular behaviors impact endogenous mechanisms of muscle recovery, we developed an agent-based model (ABM) using the Cellular-Potts framework to simulate the dynamic microenvironment of a cross-section of murine skeletal muscle tissue. We referenced more than 100 published studies to define over 100 parameters and rules that dictate the behavior of muscle fibers, satellite stem cells (SSCs), fibroblasts, neutrophils, macrophages, microvessels, and lymphatic vessels, as well as their interactions with each other and the microenvironment. We utilized parameter density estimation to calibrate the model to temporal biological datasets describing cross-sectional area (CSA) recovery, SSC, and fibroblast cell counts at multiple timepoints following injury. The calibrated model was validated by comparison of other model outputs (macrophage, neutrophil, and capillaries counts) to experimental observations. Predictions for eight model perturbations that varied cell or cytokine input conditions were compared to published experimental studies to validate model predictive capabilities. We used Latin hypercube sampling and partial rank correlation coefficient to identify in silico perturbations of cytokine diffusion coefficients and decay rates to enhance CSA recovery. This analysis suggests that combined alterations of specific cytokine decay and diffusion parameters result in greater fibroblast and SSC proliferation compared to individual perturbations with a 13% increase in CSA recovery compared to unaltered regeneration at 28 days. These results enable guided development of therapeutic strategies that similarly alter muscle physiology (i.e. converting extracellular matrix [ECM]-bound cytokines into freely diffusible forms as studied in cancer therapeutics or delivery of exogenous cytokines) during regeneration to enhance muscle recovery after injury.

Exploring immune-related pathogenesis in lung injury: Providing new insights Into ALI/ARDS

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) represent a significant global burden of morbidity and mortality, with lung injury being the primary cause of death in affected patients. The pathogenesis of lung injury, however, remains a complex issue. In recent years, the role of the immune system in lung injury has attracted extensive attention worldwide. Despite advancements in our understanding of various lung injury subtypes, significant limitations persist in both prevention and treatment. This review investigates the immunopathogenesis of ALI/ARDS, aiming to elucidate the pathological processes of lung injury mediated by dendritic cells (DCs), natural killer (NK) cells, phagocytes, and neutrophils. Furthermore, the article expounds on the critical contributions of gut microbiota, inflammatory pathways, and cytokine storms in the development of ALI/ARDS.

Immune Dysregulation in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a disease whose incidence increase with age and is characterised by chronic inflammation and significant immune dysregulation. Inhalation of toxic substances cause oxidative stress in the lung tissue as well as airway inflammation, under the recruitment of chemokines, immune cells gathered and are activated to play a defensive role. However, persistent inflammation damages the immune system and leads to immune dysregulation, which is mainly manifested in the reduction of the body's immune response to antigens, and immune cells function are impaired, further destroy the respiratory defensive system, leading to recurrent lower respiratory infections and progressive exacerbation of the disease, thus immune dysregulation play an important role in the pathogenesis of COPD. This review summarizes the changes of innate and adaptive immune-related cells during the pathogenesis of COPD, aiming to control COPD airway inflammation and improve lung tissue remodelling by regulating immune dysregulation, for further reducing the risk of COPD progression and opening new avenues of therapeutic intervention in COPD.

Implication of M2 macrophage on NLRP3 inflammasome signaling in mediating the neuroprotective effect of Canagliflozin against methotrexate-induced cognitive impairment

Methotrexate (MTX), a chemotherapeutic antimetabolite, has been linked to cognitive impairment in cancer patients. MTX-induced metabolic pathway disruption may result in decreased antioxidant activity and increased oxidative stress, influencing hippocampal neurogenesis and microglial activation. Nuclear factor-kappa B (NF-κB), an oxidative stress byproduct, has been linked to MTX toxicity via the activation of NLRP3 inflammasome signaling. Macrophage activation and polarization plays an important role in tissue injury. This differentiation may be mediated via either the Toll-like receptor 4 (TLR4) or NLRP3 inflammasome. Interestingly, Canagliflozin (CANA), a sodium-glucose cotransporter 2 (SGLT2) inhibitor has been recently reported to exert anti-inflammatory effects by modulating macrophage polarization balance. This study aimed to investigate CANA's protective effect against MTX-induced cognitive impairment, highlighting the possible involvement of TLR4/ NF-κB crosstalk with NLRP3 inflammasome activation and macrophage polarization. Forty-eight Male Wistar rats were divided into 4 groups; (1) received saline orally for 30 days and intravenously on days 8 and 15. (2) received Canagliflozin (CANA; 20 mg/kg/day; p.o.) for 30 days. (3) received MTX (75 mg/kg, i.v.) on day 8 and 15, then they were injected with four i.p. injections of leucovorin (LCV): the first dose was 6 mg/ kg after 18 h, and the remaining doses were 3 mg/kg after 26, 42, and 50 h of MTX administration. (4) received MTX and LCV as in group 3 in addition to CANA as in group 2. MTX-treated rats showed cognitive deficits in spatial and learning memory as evidenced in the novel object recognition and Morris water maze tests. MTX exerted an oxidative effect which was evident by the increase in MDA and decline in SOD, GSH and GPx. Moreover, it exerted an inflammatory effect via elevated caspase-1, IL-1β and IL-8. CANA treatment restored cognitive ability, reduced MTX-induced oxidative stress and neuroinflammation via attenuation of TLR4/NF-κB/NLRP3 signaling, and rebalanced macrophage polarization by promoting the M2 phenotype. Hence, targeting molecular mechanisms manipulating macrophage polarization may offer novel neuroprotective strategies for preventing or treating MTX-induced immune modulation and its detrimental sequel.

Modulation of experimental acute lung injury by exosomal miR-7704 from mesenchymal stromal cells acts through M2 macrophage polarization

Acute lung injury (ALI) is a life-threatening condition with limited treatment options. The pathogenesis of ALI involves macrophage-mediated disruption and subsequent repair of the alveolar barriers, which ultimately results in lung damage and regeneration, highlighting the pivotal role of macrophage polarization in ALI. Although exosomes derived from mesenchymal stromal cells have been established as influential modulators of macrophage polarization, the specific role of exosomal microRNAs (miRNAs) remains underexplored. This study aimed to elucidate the role of specific exosomal miRNAs in driving macrophage polarization, thereby providing a reference for developing novel therapeutic interventions for ALI. We found that miR-7704 is the most abundant and efficacious miRNA for promoting the switch to the M2 phenotype in macrophages. Mechanistically, we determined that miR-7704 stimulates M2 polarization by inhibiting the MyD88/STAT1 signaling pathway. Notably, intra-tracheal delivery of miR-7704 alone in a lipopolysaccharide-induced murine ALI model significantly drove M2 polarization in lung macrophages and remarkably restored pulmonary function, thus increasing survival. Our findings highlight miR-7704 as a valuable tool for treating ALI by driving the beneficial M2 polarization of macrophages. Our findings pave the way for deeper exploration into the therapeutic potential of exosomal miRNAs in inflammatory lung diseases.

Agent-based model demonstrates the impact of nonlinear, complex interactions between cytokines on muscle regeneration

Muscle regeneration is a complex process due to dynamic and multiscale biochemical and cellular interactions, making it difficult to identify microenvironmental conditions that are beneficial to muscle recovery from injury using experimental approaches alone. To understand the degree to which individual cellular behaviors impact endogenous mechanisms of muscle recovery, we developed an agent-based model (ABM) using the Cellular Potts framework to simulate the dynamic microenvironment of a cross-section of murine skeletal muscle tissue. We referenced more than 100 published studies to define over 100 parameters and rules that dictate the behavior of muscle fibers, satellite stem cells (SSC), fibroblasts, neutrophils, macrophages, microvessels, and lymphatic vessels, as well as their interactions with each other and the microenvironment. We utilized parameter density estimation to calibrate the model to temporal biological datasets describing cross-sectional area (CSA) recovery, SSC, and fibroblast cell counts at multiple time points following injury. The calibrated model was validated by comparison of other model outputs (macrophage, neutrophil, and capillaries counts) to experimental observations. Predictions for eight model perturbations that varied cell or cytokine input conditions were compared to published experimental studies to validate model predictive capabilities. We used Latin hypercube sampling and partial rank correlation coefficient to identify in silico perturbations of cytokine diffusion coefficients and decay rates to enhance CSA recovery. This analysis suggests that combined alterations of specific cytokine decay and diffusion parameters result in greater fibroblast and SSC proliferation compared to individual perturbations with a 13% increase in CSA recovery compared to unaltered regeneration at 28 days. These results enable guided development of therapeutic strategies that similarly alter muscle physiology (i.e. converting ECM-bound cytokines into freely diffusible forms as studied in cancer therapeutics or delivery of exogenous cytokines) during regeneration to enhance muscle recovery after injury.

Peroxiredoxin 3 has a crucial role in the macrophage polarization by regulating mitochondrial homeostasis

Acute lung injury (ALI) is one of the life-threatening complications of sepsis, and macrophage polarization plays a crucial role in the sepsis-associated ALI. However, the regulatory mechanisms of macrophage polarization in ALI and in the development of inflammation are largely unknown. In this study, we demonstrated that macrophage polarization occurs in sepsis-associated ALI and is accompanied by mitochondrial dysfunction and inflammation, and a decrease of PRDX3 promotes the initiation of macrophage polarization and mitochondrial dysfunction. Mechanistically, PRDX3 overexpression promotes M1 macrophages to differentiate into M2 macrophages, and enhances mitochondrial functional recovery after injury by reducing the level of glycolysis and increasing TCA cycle activity. In conclusion, we identified PRDX3 as a critical hub integrating oxidative stress, inflammation, and metabolic reprogramming in macrophage polarization. The findings illustrate an adaptive mechanism underlying the link between macrophage polarization and sepsis-associated ALI.

Autophagy-modulating biomaterials: multifunctional weapons to promote tissue regeneration

Autophagy is a self-renewal mechanism that maintains homeostasis and can promote tissue regeneration by regulating inflammation, reducing oxidative stress and promoting cell differentiation. The interaction between biomaterials and tissue cells significantly affects biomaterial-tissue integration and tissue regeneration. In recent years, it has been found that biomaterials can affect various processes related to tissue regeneration by regulating autophagy. The utilization of biomaterials in a controlled environment has become a prominent approach for enhancing the tissue regeneration capabilities. This involves the regulation of autophagy in diverse cell types implicated in tissue regeneration, encompassing the modulation of inflammatory responses, oxidative stress, cell differentiation, proliferation, migration, apoptosis, and extracellular matrix formation. In addition, biomaterials possess the potential to serve as carriers for drug delivery, enabling the regulation of autophagy by either activating or inhibiting its processes. This review summarizes the relationship between autophagy and tissue regeneration and discusses the role of biomaterial-based autophagy in tissue regeneration. In addition, recent advanced technologies used to design autophagy-modulating biomaterials are summarized, and rational design of biomaterials for providing controlled autophagy regulation via modification of the chemistry and surface of biomaterials and incorporation of cells and molecules is discussed. A better understanding of biomaterial-based autophagy and tissue regeneration, as well as the underlying molecular mechanisms, may lead to new possibilities for promoting tissue regeneration. Video Abstract.

Intratracheal administration of programmable DNA nanostructures combats acute lung injury by targeting microRNA-155

Acute lung injury (ALI) is an acute inflammatory process that can result in life-threatening consequences. Programmable DNA nanostructures have emerged as excellent nanoplatforms for microRNA-based therapeutics, offering potential nanomedicines for ALI treatment. Nonetheless, the traditional systematic administration of nanomedicines is constrained by low delivery efficiency, poor pharmacokinetics, and nonspecific side effects. Here, we identify macrophage microRNA-155 as a novel therapeutic target using the magnetic bead sorting technique. We further construct a DNA nanotubular nucleic acid drug antagonizing microRNA-155 (NT-155) for ALI treatment through intratracheal administration. Flow cytometry results demonstrate that NT-155, when inhaled, is taken up much more effectively by macrophages and dendritic cells in the bronchoalveolar lavage fluid of ALI mice. Furthermore, NT-155 effectively silences the overexpressed microRNA-155 in macrophages and exerts excellent inflammation inhibition effects in vitro and ALI mouse models. Mechanistically, NT-155 suppresses microRNA-155 expression and activates its target gene SOCS1, inhibiting the p-P65 signaling pathway and suppressing proinflammatory cytokine secretion. The current study suggests that deliberately designed nucleic acid drugs are promising nanomedicines for ALI treatment and the local administration may open up new practical applications of DNA in the future.

Treatment of leishmaniasis with chemotherapy and vaccine: a mathematical model

Leishmaniasis, an infectious disease, manifests itself mostly in two forms, cutaneous leishmaniasis (CL) and, a more severe and potentially deadly form, visceral leishmaniasis (VL). The current control strategy for leishmaniasis relies on chemotherapy drugs such as sodium antimony gluconate (SAG) and meglumine antimoniate (MA). However, all these chemotherapy compounds have poor efficacy, and they are associated with toxicity and other adverse effects, as well as drug resistance. While research in vaccine development for leishmaniasis is continuously progressing, no vaccine is currently available. However, some experimental vaccines such as LEISH-F1+MPL-SE (V) have demonstrated some efficacy when used as drugs for CL patients. In this paper we use a mathematical model to address the following question: To what extent vaccine shots can enhance the efficacy of standard chemotherapy treatment of leishmaniasis? Starting with standard MA treatment of leishmaniasis and combining it with three injections of V , we find, by Day 84, that efficacy increased from 29% to 65-91% depending on the amount of the vaccine. With two or just one injection of V , efficacy is still very high, but there is a definite resurgence of the disease by end-time.

Jingfang Granule alleviates bleomycin-induced acute lung injury via CD200-CD200R immunoregulatory pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Jingfang granules (JF), one famous traditional Chinese formula in "She Sheng Zhong Miao Fang" written by Shi-Che Zhang during the Ming Dynasty era, has been widely used to prevent epidemic diseases in history and now was recommended for the treatment of coronavirus disease 2019 (COVID-19) in China. However, the roles of JF against acute lung injury and its mechanisms remain unclear.

AIM OF THE STUDY

Acute lung injury (ALI) and its progressive acute respiratory distress syndrome (ARDS) are a continuum of lung inflammatory disease with high morbidity and mortality in clinic, especially in COVID-19 patients. The present study aims to investigate the effect of JF on ALI and clarify its underlying mechanisms for clinical application in COVID-19 control.

METHODS

Bleomycin-induced ALI mice were given oral gavage daily for seven days with or without Jingfang granules (2, 4 g/kg). The body weight, lung wet/dry weight ratios, lung appearance and tissue histopathology were evaluated. Quantitative real-time PCR, biochemical bronchoalveolar lavage fluids analysis was used to determine the gene expression of proinflammation factor and infiltrated inflammatory cells in lung. Immunofluorescence image and western blot were used to detect the markers of alveolar macrophages (AMs), endothelial cell apoptosis and changes of CD200-CD200R pathway.

RESULTS

Firstly, histopathological analysis showed that JF significantly attenuated pulmonary injury and inflammatory response in ALI mice. Then, cytokine detection, inflammatory cells assay, and JNKs and p38 pathway analysis indicated that the recruitment and activation of alveolar macrophages was the main reason to cause ALI and JF could reverse this variation. Next, immunofluorescence staining and TUNEL assay showed that JF upregulated the expression of CD200 and suppressed the apoptosis of alveolar endothelial cells. Finally, double immunofluorescence staining of CD200 and CD11c indicated that the seriously damaged tissue had the lower CD200 while more AMs infiltration, which was confirmed by RT-PCR analysis of CD200/CD200R.

CONCLUSIONS

Jingfang granules can protect lung from acu te injury and mitigate the recruitment and overactive AMs-induced inflammation via CD200-CD200R immunoregulatory signal axis, which will provide an experimental basis for Jingfang granules clinical applications in COVID-19.

Sinomenine alleviates lipopolysaccharide-induced acute lung injury via a PPARβ/δ-dependent mechanism

Evidence is mounting that sinomenine and peroxisome proliferator-activated receptor β/δ (PPARβ/δ) are effective against lipopolysaccharide (LPS)-induced acute lung injury (ALI) via anti-inflammatory properties. However, it is unknown whether PPARβ/δ plays a role in the protective effect of sinomenine on ALI. Here, we initially observed that preemptive administration of sinomenine markedly alleviated lung pathological changes, pulmonary edema and neutrophil infiltration, accompanied by inhibition of the expression of the pro-inflammatory cytokines Tumor necrosis factor-α (TNF-α) and Interleukin-6 (IL-6), which were largely reversed following the addition of a PPARβ/δ antagonist. Subsequently, we also noticed that sinomenine upregulated adenosine A_2A receptor expression in a PPARβ/δ-dependent manner in LPS-stimulated bone marrow-derived macrophages (BMDMs). Further investigation indicated that PPARβ/δ directly bound to the functional peroxisome proliferator responsive element (PPRE) in the adenosine A_2A receptor gene promoter region to enhance the expression of the adenosine A_2A receptor. Sinomenine was identified as a PPARβ/δ agonist. It could bind with PPARβ/δ, and promote the nuclear translocation and transcriptional activity of PPARβ/δ. In addition, combined treatment with sinomenine and an adenosine A_2A receptor agonist exhibited synergistic effects and better protective roles than their single use against ALI. Taken together, our results reveal that sinomenine exerts advantageous effects on ALI by activating of PPARβ/δ, with the subsequent upregulation of adenosine A_2A receptor expression, and provide a novel and potential therapeutic application for ALI.

"Zombie" Macrophages for Targeted Drug Delivery to Treat Acute Pneumonia

A cell-based drug delivery system has emerged as a promising drug delivery platform. Due to their innate inflammatory tropism, natural and engineered macrophages have exhibited targeted accumulation in inflammatory tissues, which has allowed targeted delivery of medicine for the treatment of a variety of inflammatory diseases. Nevertheless, live macrophages may take up the medicine and metabolize it during preparation, storage, and in vivo delivery, sometimes causing unsatisfactory therapeutic efficacy. In addition, live macrophage-based drug delivery systems are usually freshly prepared and injected, due to the poor stability that does not allow storage. "Off-the-shelf" products would be indeed conducive to the timely therapy of acute diseases. Herein, a cryo-shocked macrophage-based drug delivery system was developed via supramolecular conjugation of cyclodextrin (CD)-modified "zombie" macrophages and adamantane (ADA)-functionalized nanomedicine. "Zombie" macrophages exhibited a much better storage stability over time than their counterpart live macrophage drug carriers and maintained cell morphology, membrane integrity, and biological functions. In an acute pneumonia mouse model, "zombie" macrophages carried quercetin-loaded nanomedicine, hand-in-hand, to the inflammatory lung tissues and effectively alleviated the inflammation in mice.

Scavenger receptor A-mediated nanoparticles target M1 macrophages for acute liver injury

Acute liver injury (ALI) has an elevated fatality rate due to untimely and ineffective treatment. Although, schisandrin B (SchB) has been extensively used to treat diverse liver diseases, its therapeutic efficacy on ALI was limited due to its high hydrophobicity. Palmitic acid-modified serum albumin (PSA) is not only an effective carrier for hydrophobic drugs, but also has a superb targeting effect via scavenger receptor-A (SR-A) on the M1 macrophages, which are potential therapeutic targets for ALI. Compared with the common macrophage-targeted delivery systems, PSA enables site-specific drug delivery to reduce off-target toxicity. Herein, we prepared SchB-PSA nanoparticles and further assessed their therapeutic effect on ALI. In vitro, compared with human serum albumin encapsulated SchB nanoparticles (SchB-HSA NPs), the SchB-PSA NPs exhibited more potent cytotoxicity on lipopolysaccharide (LPS) stimulated Raw264.7 (LAR) cells, and LAR cells took up PSA NPs 8.79 times more than HSA NPs. As expected, the PSA NPs also accumulated more in the liver. Moreover, SchB-PSA NPs dramatically reduced the activation of NF-κB signaling, and significantly relieved inflammatory response and hepatic necrosis. Notably, the high dose of SchB-PSA NPs improved the survival rate in 72 h of ALI mice to 75%. Hence, SchB-PSA NPs are promising to treat ALI.

Osteoporosis remission via an anti-inflammaging effect by icariin activated autophagy

The pace of bone formation slows down with aging, which leads to the development of osteoporosis. In addition to senescent bone marrow mesenchymal stem cells (S-BMSCs), senescent macrophages (S-MΦs) present in the bone marrow produce numerous inflammatory cytokines that contribute to the inflammaged microenvironment and are involved in the development of osteoporosis. Although autophagy activation has shown a significant anti-aging effect, its influence on inflammaging and its role in osteoporosis treatment remain unclear. Traditional Chinese herbal medicine contains bioactive components that exhibit remarkable advantages in bone regeneration. We have demonstrated that icariin (ICA), a bioactive component of traditional Chinese herbal medicine, activates autophagy, exerts a significant anti-inflammaging effect on S-MΦs, and rejuvenates osteogenesis of S-BMSCs, thereby alleviating bone loss in osteoporotic mice. The transcriptomic analysis further reveals that the TNF-α signaling pathway, which is significantly associated with the level of autophagy, regulates this effect. Moreover, the expression of senescence-associated secretory phenotype (SASP) is significantly reduced after ICA treatment. In summary, our findings suggest that bioactive components/materials targeting autophagy can effectively modulate the inflammaging of S-MΦs, offering an innovative treatment strategy for osteoporosis remission and various age-related comorbidities.

Neonatal hyperoxia induces activated pulmonary cellular states and sex-dependent transcriptomic changes in a model of experimental bronchopulmonary dysplasia

Hyperoxia disrupts lung development in mice and causes bronchopulmonary dysplasia (BPD) in neonates. To investigate sex-dependent molecular and cellular programming involved in hyperoxia, we surveyed the mouse lung using single cell RNA sequencing (scRNA-seq), and validated our findings in human neonatal lung cells in vitro. Hyperoxia-induced inflammation in alveolar type (AT) 2 cells gave rise to damage-associated transient progenitors (DATPs). It also induced a new subpopulation of AT1 cells with reduced expression of growth factors normally secreted by AT1 cells, but increased mitochondrial gene expression. Female alveolar epithelial cells had less EMT and pulmonary fibrosis signaling in hyperoxia. In the endothelium, expansion of Car4+ EC (Cap2) was seen in hyperoxia along with an emergent subpopulation of Cap2 with repressed VEGF signaling. This regenerative response was increased in females exposed to hyperoxia. Mesenchymal cells had inflammatory signatures in hyperoxia, with a new distal interstitial fibroblast subcluster characterized by repressed lipid biosynthesis and a transcriptomic signature resembling myofibroblasts. Hyperoxia-induced gene expression signatures in human neonatal fibroblasts and alveolar epithelial cells in vitro resembled mouse scRNA-seq data. These findings suggest that neonatal exposure to hyperoxia programs distinct sex-specific stem cell progenitor and cellular reparative responses that underpin lung remodeling in BPD.

Cancer therapy with immune checkpoint inhibitor and CSF-1 blockade: A mathematical model

Immune checkpoint inhibitors (ICIs) introduced in recent years have revolutionized the treatment of many metastatic cancers. However, data suggest that treatment has benefits only in a limited percentage of patients, and that this is due to immune suppression of the tumor microenvironment (TME). Anti-tumor inflammatory macrophages (M1), which are attracted to the TME, are converted by tumor secreted cytokines, such as CSF-1, to pro-tumor anti-inflammatory macrophages (M2), or tumor associated macrophages (TAMs), which block the anti-tumor T cells. In the present paper we develop a mathematical model that represents the interactions among the immune cells and cancer in terms of differential equations. The model can be used to assess treatments of combination therapy of anti-PD-1 with anti-CSF-1. Examples are given in comparing the efficacy among different strategies for anti-CSF-1 dosing in a setup of clinical trials.

Molybdenum and cadmium co-exposure promotes M1 macrophage polarization through oxidative stress-mediated inflammatory response and induces pulmonary fibrosis in Shaoxing ducks (Anas platyrhyncha)

High molybdenum (Mo) and cadmium (Cd) are harmful to the body, but pulmonary toxicity induced by Mo and Cd co-exposure is unknown. To assess the combined impacts of Mo and Cd on fibrosis through M1 polarization in the lung of ducks, 80 healthy 8-day-old Shaoxing ducks (Anas platyrhyncha) were randomly assigned to 4 groups and fed with containing unequal doses of Mo or/and Cd diet. Lung tissues were collected on the 16th week. Results indicated that Mo or/and Cd significantly increased their contents in the lungs, and led to trace elements disorder and histological abnormality, and oxidative stress accompanied by promoting contents of H₂ O₂ and MDA and decreasing activities of T-SOD, GSH-Px, and CAT, then activated the TLR4/NF-κB/NLRP3 pathway accompanied by upregulating Caspase-1, ASC, IL-18, IL-1β, TLR4, NF-κB, and NLRP3 expression levels, and disrupted M1/M2 balance to divert toward M1, which evoked the TGF-β/Smad2/3-mediated fibrosis by elevating TGF-β1, Smad2, Smad3, COL1A1, α-SMA, and MMP2 expression levels, and decreasing Smad7 and TIMP2 expression levels. The changes of the combined group were most obvious. To sum up, the research demonstrated that Mo or/and Cd may cause macrophages to polarize toward M1 by oxidative stress-mediated the TLR4/NF-κB/NLRP3 pathway, then result in fibrosis through the TGF-β1/Smad2/3 pathway in duck lungs. Mo and Cd may worsen lung damage.

5-Methoxyflavone alleviates LPS-mediated lung injury by promoting Nrf2-mediated the suppression of NOX4/TLR4 axis in bronchial epithelial cells and M1 polarization in macrophages

BACKGROUND

Acute lung injury (ALI) arises from sepsis or bacterial infection, which are life-threatening respiratory disorders that cause the leading cause of death worldwide. 5-Methoxyflavone, a methylated flavonoid, is gaining increased attention for its various health benefits. In the current study, we investigated the potential effects of 5-methoxyflavone against LPS-mediated ALI and elucidated the corresponding possible mechanism.

METHODS

A mouse model with ALI was established by intratracheal instillation of LPS, and lung pathological changes, signaling pathway related proteins and apoptosis in lung tissues were estimated by H&E staining, immunofluorescence and TUNEL assay, respectively. Cell viability was evaluated by MTT assay; protein levels of pro-inflammatory mediators were measured by ELISA assay; levels of ROS and M1 macrophage polarization were assayed by flow cytometry; the expression of Nrf2 signaling, NOX4/TLR4 axis and P-STAT1 were detected by western blotting.

RESULTS

Our results showed that 5-methoxyflavone treatment inhibited LPS-induced expression of NOX4 and TLR4 as well as the activation of downstream signaling (NF-κB and P38 MAPK), which was accompanied by markedly decreased ROS levels and pro-inflammatory cytokines (IL-6, TNF-α, MCP-1, and IL-8) in BEAS-2B cells. Moreover, we revealed that these effects of 5-methoxyflavone were related to its Nrf2 activating property, and blockade of Nrf2 prevented its inhibitory effects on NOX4/TLR4/NF-κB/P38 MAPK signaling, thus abrogating the anti-inflammatory effects of 5-methoxyflavone. Besides, the Nrf2 activating property of 5-methoxyflavone in RAW264.7 cells led to inhibition of LPS/IFN-γ-mediated STAT1 signaling, resulting in suppression of LPS/IFN-γ-induced M1 macrophage polarization and the repolarization of M2 macrophages to M1. In a mouse model of LPS-induced ALI, 5-methoxyflavone administration ameliorated LPS-mediated lung pathological changes, the increased lung index (lung/body weight ratio), and epithelial cell apoptosis. Meanwhile, we found 5-methoxyflavone effectively suppressed the hyperactive signaling pathways and the production of excessive pro-inflammatory mediators. Moreover, 5-methoxyflavone reduced LPS-mediated M1 macrophage polarization associated with elevated P-STAT1 activation in the lung tissues. In addition, 5-methoxyflavone improved the survival of LPS-challenged mice.

CONCLUSION

These results indicated that 5-methoxyflavone might be suitable for the development of a novel drug for ALI therapeutic.

BP5 alleviates endotoxemia-induced acute lung injury by activating Nrf2 via dual regulation of the Keap1-Nrf2 interaction and the Akt (Ser473)/GSK3β (Ser9)/Fyn pathway

Oxidative stress and inflammation play a crucial role in the pathogenesis of acute lung injury (ALI). Previously, pentapeptide bursopentin (BP5, Cys-Lys-Arg-Val-Tyr) was reported to possess significant antioxidant activity and inhibit lipopolysaccharides (LPS)-induced NF-κB activation in vitro, whereas little is known about its effects in vivo. In this study, we explored the effects of BP5 on endotoxemia-induced ALI in mice and the underlying molecular mechanisms. Our studies revealed that BP5 markedly improved survival and effectively alleviated lung injury by reducing overoxidation and excessive inflammatory response in endotoxemia mice. In LPS-stimulated mouse primary macrophages and RAW 264.7 cells, BP5 also exhibited antioxidant and anti-inflammatory properties by enhancing Nrf2 activation. Importantly, these beneficial effects were abolished by Nrf2 knockdown. To further elucidate the underlying mechanisms, we performed localized surface plasmon resonance (LSPR) assays, molecular docking, together with cell-based studies, and found that BP5 inhibited the Keap1-Nrf2 interaction to promote Nrf2 nuclear translocation and activation. Moreover, BP5-induced Nrf2 activation was shown to be accompanied by an increase in the phosphorylation of Akt (at Ser473) and GSK3β (at Ser9), and a decrease in Fyn nuclear accumulation both in vitro and in vivo. Pharmacologically inhibiting phosphorylation of Akt and GSK3β obviously enhanced Fyn nuclear accumulation in RAW 264.7 cells, which partially attenuated the promoting effect of BP5 on Nrf2 nuclear accumulation and activation. Furthermore, In Nrf2^-/- mice, the protective effects of BP5 on the endotoxemia-induced ALI in WT mice were largely vanished. Our findings indicated that BP5 effectively protected endotoxemia-induced ALI against oxidative stress and inflammatory response, which are largely dependent on activation of the Nrf2 pathway. Underlying mechanisms include dual regulation of the Keap-Nrf2 interaction and the Akt (Ser473)/GSK3β (Ser9)/Fyn pathway.

C/EBPβ Promotes LPS-Induced IL-1β Transcription and Secretion in Alveolar Macrophages via NOD2 Signaling

Objective

C/EBPβ, a crucial transcription factor, regulates innate immunity and inflammatory responses. However, the role played by C/EBPβ in alveolar macrophage (AM) inflammatory responses remains unknown. This study aimed to investigate the role and mechanism of C/EBPβ in alveolar macrophages (AMs) from the transcriptional level and to search for natural compounds targeting C/EBPβ.

Methods

Rat AMs were infected with Lv-sh-C/EBPβ and treated with LPS, and the expression levels of iNOS, TNF-α, IL-6, and IL-1β were measured by RT-qPCR, Western blotting, and ELISA. Mechanistically, transcriptome sequencing (RNA-seq) revealed changes in gene expression patterns in AMs after LPS stimulation and C/EBPβ knockdown. Functional enrichment analyses and rescue experiments identified and validated inflammation-associated cell signaling pathways regulated by C/EBPβ. Furthermore, virtual screening was used to search for natural compounds that inhibit C/EBPβ with the structure of helenalin as a reference.

Results

Following stimulation with LPS, AMs exhibited an increased expression of C/EBPβ. C/EBPβ knockdown significantly decreased the expression levels of inflammatory mediators. A total of 374 differentially expressed genes (DEGs) were identified between LPS-stimulated C/EBPβ knockdown and negative control cells. The NOD-like receptor signaling may be a key target for C/EBPβ, according to functional enrichment analyses of the DEGs. Further experiments showed that the muramyl dipeptide (MDP, NOD2 agonist) reversed the downregulation of inflammatory mediators and the NF-κB pathway caused by the C/EBPβ knockdown. The virtual screening revealed that N-caffeoyltryptophan, orilotimod, and petasiphenone have comparable pharmacological properties to helenalin (a known C/EBPβ inhibitor) and demonstrate a great binding capacity to C/EBPβ.

Conclusion

Ablation of C/EBPβ may attenuate LPS-induced inflammatory damage in AMs by inhibiting the NOD2 receptor signaling pathway. Three natural compounds, N-caffeoyltryptophan, orilotimod, and petasiphenone, may be potential C/EBPβ inhibitors.

Supramolecular erythrocytes-hitchhiking drug delivery system for specific therapy of acute pneumonia

Acute pneumonia is an inflammatory syndrome often associated with severe multi-organ dysfunction and high mortality. The therapeutic efficacy of current anti-inflammatory medicines is greatly limited due to the short systemic circulation and poor specificity in the lungs. New drug delivery systems (DDS) are urgently needed to efficiently transport anti-inflammatory drugs to the lungs. Here, we report an inflammation-responsive supramolecular erythrocytes-hitchhiking DDS to extend systemic circulation of the nanomedicine via hitchhiking red blood cells (RBCs) and specifically "drop off" the payloads in the inflammatory lungs. β-cyclodextrin (β-CD) modified RBCs and ferrocene (Fc) modified liposomes (NP) were prepared and co-incubated to attach NP to RBCs via β-CD/Fc host-guest interactions. RBCs extended the systemic circulation of the attached NP, meanwhile, the NP may get detached from RBCs due to the high ROS level in the inflammatory lungs. In acute pneumonia mice, this strategy delivered curcumin specifically to the lungs and effectively alleviated the inflammatory syndrome.

Leishmania infection-derived extracellular vesicles drive transcription of genes involved in M2 polarization

Although it is known that the composition of extracellular vesicles (EVs) is determined by the characteristics of the cell and its environment, the effects of intracellular infection on EV composition and functions are not well understood. We had previously shown that cultured macrophages infected with Leishmania parasites release EVs (LiEVs) containing parasite-derived molecules. In this study we show that LdVash, a molecule previously identified in LiEVs from L. donovani infected RAW264.7 macrophages, is widely distributed in the liver of L. donovani infected mice. This result shows for the first time that parasite molecules are released in EVs and distributed in infected tissues where they can be endocytosed by cells in the liver, including macrophages that significantly increase numbers as the infection progresses. To evaluate the potential impact of LiEVs on macrophage functions, we show that primary peritoneal exudate macrophages (PECs) express transcripts of signature molecules of M2 macrophages such as arginase 1, IL-10, and IL-4R when incubated with LiEVs. In comparative studies that illustrate how intracellular pathogens control the composition and functions of EVs released from macrophages, we show that EVs from RAW264.7 macrophages infected with Salmonella Typhimurium activate PECs to express transcripts of signature molecules of M1 macrophages such as iNOS, TNF alpha, and IFN-gamma and not M2 signature molecules. Finally, in contrast to the polarized responses observed in in vitro studies of macrophages, both M1 and M2 signature molecules are detected in L. donovani infected livers, although they exhibit differences in their spatial distribution in infected tissues. In conclusion, EVs produced by macrophages during Leishmania infection lead to the gene expression consistent with M2 polarization. In contrast, the EVs produced during S. Typhimurium infection stimulated the transcription of genes associated with M1 polarization.

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.

ACT001 suppressing M1 polarization against inflammation via NF-κB and STAT1 signaling pathways alleviates acute lung injury in mice

ACT001 has been shown to exhibit excellent antitumor and anti-fibrosis activities. However, the role of ACT001 in acute lung injury (ALI) and the underlying mechanism remains largely unclear. The present study aimed to investigate the protective effects of ACT001 on ALI and explore the potential mechanisms. Herein, we firstly established the ALI mouse model induced by intratracheal instillation of lipopolysaccharide (LPS). ACT001 treatment significantly alleviated histopathological changes of lung tissues with lower infiltration of pulmonary M1 macrophages in ALI mice. Then, we performed in vitro experiment and found that ACT001 treatment effectively inhibited the M1 phenotype of RAW264.7 and THP-1.. Next, we performed pull-down and mass spectrometry analysis to screen the interacting proteins of ACT001, identifying IKKβ and STAT1 as the critical target proteins of ACT001. And ACT001 treatment significantly suppressed the NF-κB and STAT1 pathways, thereby inhibiting the M1 polarization against inflammation in vivo and in vitro. Finally, we used IMD 0354 (IMD) and Fludarabine (Flud) to specifically block the activity of IKKβ and STAT1, and stimulated macrophages through IKKβ and STAT1 overexpression. Our data clearly showed that ACT001-induced decrease of the M1 polarization was blocked by IMD and Flud treatment, and reversed by IKKβ and STAT1 overexpression in RAW264.7 cells. In conclusion, we discovered that ACT001 significantly alleviates inflammation and limits M1 phenotype of pulmonary macrophages via suppressing NF-κB and STAT1 signaling pathways, providing new insights for the development of drugs to treat ALI/ARDS.

An mTOR siRNA-Loaded Spermidine/DNA Tetrahedron Nanoplatform with a Synergistic Anti-Inflammatory Effect on Acute Lung Injury

Acute lung injury (ALI) is characterized by severe inflammation and damage to the lung air-blood barrier, resulting in respiratory function damage and life-threatening outcomes. Macrophage polarization plays an essential role in the occurrence, development, and outcome of ALI. As drug carriers, self-assembled DNA nanostructures can potentially overcome the drawbacks and limitations of traditional anti-inflammatory agents owing to their nontoxicity, programmability, and excellent structural control at the nanoscale. A small interfering RNA (siRNA) and drug dual therapy nanoplatform are proposed and constructed here to combat ALI. The nanoplatform consists of a spermidine-assembled DNA tetrahedron and four mammalian target of rapamycin siRNAs. Spermidine serves as a mediator of drug delivery vehicle synthesis and a drug that alters macrophage polarization. Both spermidine and siRNA exert anti-inflammatory effects in vitro and in vivo by regulating the macrophage phenotype. More importantly, these factors exhibit a synergistic anti-inflammatory effect by promoting macrophage autophagy. For the first time, an anti-inflammatory dual therapy strategy that uses self-assembled DNA nanostructures as nontoxic, programmable delivery vehicles is proposed and demonstrated through this work. Future work on utilizing DNA nanostructures for the treatment of noncancerous diseases such as ALI is highly promising and desirable.

Tracheal Macrophages During Regeneration and Repair of Long-Segment Airway Defects

OBJECTIVES/HYPOTHESIS

Tissue-engineered tracheal grafts (TETGs) offer a potential solution for repair of long-segment airway defects. However, preclinical and clinical TETGs have been associated with chronic inflammation and macrophage infiltration. Macrophages express great phenotypic heterogeneity (generally characterized as classically activated [M1] vs. alternatively activated [M2]) and can influence tracheal repair and regeneration. We quantified and characterized infiltrating host macrophages using mouse microsurgical tracheal replacement models.

STUDY DESIGN

Translational research, animal model.

METHODS

We assessed macrophage infiltration and phenotype in animals implanted with syngeneic tracheal grafts, synthetic TETGs, or partially decellularized tracheal scaffolds (DTSs).

RESULTS

Macrophage infiltration was observed following tracheal replacement with syngeneic trachea. Both M1 and M2 macrophages were present in native trachea and increased during early tracheal repair (P = .014), with an M1/M2 ratio of 0.48 ± 0.15. In contrast, orthotopic implantation of synthetic TETGs resulted in a shift to M1 predominant macrophage phenotype with an increased M1/M2 ratio of 1.35 ± 0.41 by 6 weeks following implant (P = .035). Modulation of the synthetic scaffold with the addition of polyglycolic acid (PGA) resulted in a reduction of M1/M2 ratio due to an increase in M2 macrophages (P = .006). Using systemic macrophage depletion, the M1/M2 ratio reverted to native values in synthetic TETG recipients and was associated with an increase in graft epithelialization. Macrophage ratios seen in DTSs were similar to native values.

CONCLUSIONS

M1 and M2 macrophages are present during tracheal repair. Poor epithelialization with synthetic TETG is associated with an elevation of the M1/M2 ratio. Macrophage phenotype can be altered with scaffold composition and host-directed systemic therapies. DTSs exhibit M1/M2 ratios similar to those seen in native trachea and syngeneic tracheal replacement.

LEVEL OF EVIDENCE

NA Laryngoscope, 132:737-746, 2022.

The Emerging Role of Macrophages in Chronic Obstructive Pulmonary Disease: The Potential Impact of Oxidative Stress and Extracellular Vesicle on Macrophage Polarization and Function

Chronic obstructive pulmonary disease (COPD) is one of the most common airway diseases, and it is considered a major global health problem. Macrophages are the most representative immune cells in the respiratory tract, given their role in surveying airways, removing cellular debris, immune surveillance, and resolving inflammation. Macrophages exert their functions by adopting phenotypical changes based on the stimuli they receive from the surrounding tissue. This plasticity is described as M1/M2 macrophage polarization, which consists of a strictly coordinated process leading to a difference in the expression of surface markers, the production of specific factors, and the execution of biological activities. This review focuses on the role played by macrophages in COPD and their implication in inflammatory and oxidative stress processes. Particular attention is on macrophage polarization, given macrophage plasticity is a key feature in COPD. We also discuss the regulatory influence of extracellular vesicles (EVs) in cell-to-cell communications. EV composition and cargo may influence many COPD-related aspects, including inflammation, tissue remodeling, and macrophage dysfunctions. These findings could be useful for better addressing the role of macrophages in the complex pathogenesis and outcomes of COPD.

Deleterious effect of bone marrow-resident macrophages on hematopoietic stem cells in response to total body irradiation

Bone marrow resident macrophages interact with a population of long-term hematopoietic stem cell (LT-HSC) but their role on LT-HSC properties after stress is not well defined. Here, we show that a 2 Gy total body irradiation (TBI)-mediated death of LT-HSC is associated with increased percentages of LT-HSC with reactive oxygen species (ROS) and of bone marrow resident macrophages producing nitric oxide (NO), resulting in an increased percentage of LT-HSC with endogenous cytotoxic peroxynitrites. Pharmacological or genetic depletion of bone marrow resident macrophages impairs the radio-induced increases in the percentage of both ROS+ LT-HSC and peroxynitrite+ LT-HSC and results in a complete recovery of a functional pool of LT-HSC. Finally, we show that after a 2 Gy-TBI, a specific decrease of NO production by bone marrow resident macrophages improves the LT-HSC recovery, whereas an exogenous NO delivery decreases the LT-HSC compartment. Altogether, these results show that bone marrow resident macrophages are involved in the response of LT-HSC to a 2 Gy-TBI and suggest that regulation of NO production can be used to modulate some deleterious effects of a TBI on LT-HSC.

Tendon Immune Regeneration: Insights on the Synergetic Role of Stem and Immune Cells during Tendon Regeneration

Tendon disorders represent a very common pathology in today’s population, and tendinopathies that account 30% of tendon-related injuries, affect yearly millions of people which in turn cause huge socioeconomic and health repercussions worldwide. Inflammation plays a prominent role in the development of tendon pathologies, and advances in understanding the underlying mechanisms during the inflammatory state have provided additional insights into its potential role in tendon disorders. Different cell compartments, in combination with secreted immune modulators, have shown to control and modulate the inflammatory response during tendinopathies. Stromal compartment represented by tenocytes has shown to display an important role in orchestrating the inflammatory response during tendon injuries due to the interplay they exhibit with the immune-sensing and infiltrating compartments, which belong to resident and recruited immune cells. The use of stem cells or their derived secretomes within the regenerative medicine field might represent synergic new therapeutical approaches that can be used to tune the reaction of immune cells within the damaged tissues. To this end, promising opportunities are headed to the stimulation of macrophages polarization towards anti-inflammatory phenotype together with the recruitment of stem cells, that possess immunomodulatory properties, able to infiltrate within the damaged tissues and improve tendinopathies resolution. Indeed, the comprehension of the interactions between tenocytes or stem cells with the immune cells might considerably modulate the immune reaction solving hence the inflammatory response and preventing fibrotic tissue formation. The purpose of this review is to compare the roles of distinct cell compartments during tendon homeostasis and injury. Furthermore, the role of immune cells in this field, as well as their interactions with stem cells and tenocytes during tendon regeneration, will be discussed to gain insights into new ways for dealing with tendinopathies.

Therapeutic effect of pH-Responsive dexamethasone prodrug nanoparticles on acute lung injury

Acute lung injury/inflammation (ALI) is usually caused by various injury factors inside and outside the lung, which can be transformed into acute respiratory distress syndrome (ARDS) in severe cases. Alveolar macrophages play a key role in the pathogenesis of ALI, which regulate inflammatory responses by secreting inflammatory mediators. Therefore, we prepared dexamethasone (DXM)/mannose co-modified branched polyethyleneimine (PEI) (DXM-PEI-mannose, DPM) prodrug nanopartcales, which could effectively target the mannose receptor (MR) on the surface of alveolar macrophages and be used for the treatment of ALI. The DXM-PEI (DP) prodrug was obtained by linking DXM with branched PEI through Schiff base reaction. Subsequently, the pH-responsive DPM prodrug was obtained by using mannose-targeted head modification. The DPM prodrug NPs with a particle size of 115 ± 1 nm, a polydispersity index (PDI) value of 0.054 ± 0.018, and a zeta potential of 31 ± 1 mV were obtained by cross-linking. The drug loading of DPM prodrug NPs measured by the acid hydrolysis method was 51.88%, which had good serum stability and biocompatibility. By comparing the stability and property release of prodrug NPs under different pH (7.4 and 5.0) conditions, it showed that DPM prodrug NPs had certain sensitivity to the micro-acid environment. To study the targeting of mouse mononuclear macrophages, mannose-modified prodrug NPs showed significant in vitro targeting. Moreover, prodrug NPs showed good anti-inflammatory activity in vitro, which was significantly different from free drugs. In vivo biodistribution experiments also showed that it had a long-term lung targeting effect. DPM prodrug NPs also had a good therapeutic effect on ALI. In conclusion, the mannose-modified DXM prodrug NPs delivery system could specifically target lung tissues and have a good therapeutic effect, which might be useful for the treatment of lung diseases.

Nicaraven prevents the fast growth of inflamed tumors by an anti-inflammatory mechanism

Inflammatory microenvironment is known to accelerate the progression of malignant tumors. We investigated the possible anti-inflammatory effect of nicaraven on slowing tumor growth. Tumor-bearing mice randomly received nicaraven injection (50 mg/kg daily, i.p, n = 8) or placebo treatment (n = 8) for 10 days, and then sacrificed for evaluations. Nicaraven administration effectively inhibited the fast growth of tumor, as a large tumor (> 1.0 g) developed finally in three of the eight mice received placebo treatment. Cytokines/chemokines array indicated that nicaraven reduced the levels of CXCL10 and SDF-1 in the tumor as well as the levels of IL-2 and MIP-2 in serum. Immunofluorescence staining showed that nicaraven significantly reduced the recruitment of macrophages and neutrophils in the tumor. Interestingly, western blot indicated that the expression of CD86, CD206, and NIMP-R14 was especially enhanced in the three large-size tumors, suggesting the potential role of nicaraven in preventing the hyper-inflammatory tumor microenvironment. Moreover, the expression of PARP-1 was downregulated, but the expression of phospho-p38 MAPK, phospho-MKK-3/6, and phospho-MSK-1 was upregulated in the large-size tumors, suggesting the involvement of p38 MAPK pathway in the anti-inflammatory effect of nicaraven. Taken together, our study suggests that nicaraven may effectively prevent the fast growth of inflamed tumors by an anti-inflammatory mechanism.

Inflammation-modulating nanoparticles for pneumonia therapy

Pneumonia is a common but serious infectious disease, and is the sixth leading cause for death. The foreign pathogens such as viruses, fungi, and bacteria establish an inflammation response after interaction with lung, leading to the filling of bronchioles and alveoli with fluids. Although the pharmacotherapies have shown their great effectiveness to combat pathogens, advanced methods are under developing to treat complicated cases such as virus-infection and lung inflammation or acute lung injury (ALI). The inflammation modulation nanoparticles (NPs) can effectively suppress immune cells and inhibit inflammatory molecules in the lung site, and thereby alleviate pneumonia and ALI. In this review, the pathological inflammatory microenvironments in pneumonia, which are instructive for the design of biomaterials therapy, are summarized. The focus is then paid to the inflammation-modulating NPs that modulate the inflammatory cells, cytokines and chemokines, and microenvironments of pneumonia for better therapeutic effects. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Respiratory Disease.

Modified Xiaoqinglong decoction alleviates lipopolysaccharide-induced acute lung injury in mice by regulating arachidonic acid metabolism and exerting anti-apoptotic and anti-inflammatory effects

Effective therapeutics are not available for acute lung injury (ALI) and acute respiratory distress syndrome. Modified Xiaoqinglong decoction (M-XQL) is reported to effectively treat pneumonia, but the underlying mechanisms are unclear. In this study, the therapeutic effect and mechanism of M-XQL were examined using a lipopolysaccharide (LPS)-induced ALI mouse model. The effects of M-XQL on lung injury, inflammatory responses, and cell apoptosis were analyzed. Additionally, high-throughput sequencing was performed to evaluate the therapeutic mechanism of M-XQL. Pretreatment with M-XQL significantly and dose-dependently mitigated the pathological changes and upregulation of pulmonary, nitric oxide content and cell apoptosis and serum tumor necrosis factor-alpha contents in the LPS-induced ALI mouse model. RNA sequencing analysis revealed that the expression of several arachidonic acid metabolism-associated genes in the LPS + high-dose M-XQL group differed from that in the LPS group. In particular, the Cbr2, Cyp4f18, and Cyp2e1 levels were upregulated, whereas the Alox12, Ptges, and Ptges2 levels were downregulated in the LPS + high-dose M-XQL group. These results suggest that M-XQL exerts therapeutic effects in ALI mice by regulating arachidonic acid metabolism and exerting anti-apoptotic and anti-inflammatory effects. Thus, M-XQL is a potential agent for the clinical treatment of ALI.

Idiopathic Pulmonary Comorbidities and Mechanisms

Idiopathic pulmonary fibrosis (IPF) is a disease with an unknown etiology mainly characterized by a progressive decline of lung function due to the scarring of the tissue deep in the lungs. The overall survival after diagnosis remains low between 3 and 5 years. IPF is a heterogeneous disease and much progress has been made in the past decade in understanding the disease mechanisms that contributed to the development of two new drugs, pirfenidone and nintedanib, which improved the therapeutic management of the disease. The understanding of the cofactors and comorbidities of IPF also contributed to improved management of the disease outcome. In the present review, we evaluate scientific evidence which indicates IPF as a risk factor for other diseases based on the complexity of molecular and cellular mechanisms involved in the disease development and of comorbidities. We conclude from the existing literature that while much progress has been made in understating the mechanisms involved in IPF development, further studies are still necessary to fully understand IPF pathogenesis which will contribute to the identification of novel therapeutic targets for IPF management as well as other diseases for which IPF is a major risk factor.

Novel pharmacological strategies to treat cognitive dysfunction in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major incurable global health burden and currently the 3rd largest cause of death in the world, with approximately 3.23 million deaths per year. Globally, the financial burden of COPD is approximately €82 billion per year and causes substantial morbidity and mortality. Importantly, much of the disease burden and health care utilisation in COPD is associated with the management of its comorbidities and viral and bacterial-induced acute exacerbations (AECOPD). Recent clinical studies have shown that cognitive dysfunction is present in up to 60% of people with COPD, with impairments in executive function, memory, and attention, impacting on important outcomes such as quality of life, hospitalisation and survival. The high prevalence of cognitive dysfunction in COPD may also help explain the insufficient adherence to therapeutic plans and strategies, thus worsening disease progression in people with COPD. However, the mechanisms underlying the impaired neuropathology and cognition in COPD remain largely unknown. In this review, we propose that the observed pulmonary oxidative burden and inflammatory response of people with COPD 'spills over' into the systemic circulation, resulting in damage to the brain and leading to cognitive dysfunction. As such, drugs targeting the lungs and comorbidities concurrently represent an exciting and unique therapeutic opportunity to treat COPD and cognitive impairments, which may lead to the production of novel targets to prevent and reverse the debilitating and life-threatening effects of cognitive dysfunction in COPD.

Coagulation Dysfunction in Acute Respiratory Distress Syndrome and Its Potential Impact in Inflammatory Subphenotypes

The Acute Respiratory Distress Syndrome (ARDS) has caused innumerable deaths worldwide since its initial description over five decades ago. Population-based estimates of ARDS vary from 1 to 86 cases per 100,000, with the highest rates reported in Australia and the United States. This syndrome is characterised by a breakdown of the pulmonary alveolo-epithelial barrier with subsequent severe hypoxaemia and disturbances in pulmonary mechanics. The underlying pathophysiology of this syndrome is a severe inflammatory reaction and associated local and systemic coagulation dysfunction that leads to pulmonary and systemic damage, ultimately causing death in up to 40% of patients. Since inflammation and coagulation are inextricably linked throughout evolution, it is biological folly to assess the two systems in isolation when investigating the underlying molecular mechanisms of coagulation dysfunction in ARDS. Although the body possesses potent endogenous systems to regulate coagulation, these become dysregulated and no longer optimally functional during the acute phase of ARDS, further perpetuating coagulation, inflammation and cell damage. The inflammatory ARDS subphenotypes address inflammatory differences but neglect the equally important coagulation pathway. A holistic understanding of this syndrome and its subphenotypes will improve our understanding of underlying mechanisms that then drive translation into diagnostic testing, treatments, and improve patient outcomes.

Effects of Ultrashort Wave Therapy on Inflammation and Macrophage Polarization after Acute Lung Injury in Rats

Acute lung injury (ALI) features dysregulated pulmonary inflammation. Ultrashort waves (USWs) exert anti-inflammatory effects but no studies have evaluated their activity in ALI. Herein, we used an in vivo lipopolysaccharide (LPS)-induced ALI model to investigate whether the anti-inflammatory activity of USWs is mediated by altering the polarization of M1 to M2 macrophages. Twenty-four male Sprague-Dawley rats were randomly divided into control, untreated ALI, and ALI treated with USW groups (n = 8 in each group). ALI was induced by intratracheal LPS instillation. Rats in the USW group were treated for 15 min at 0, 4, and 8 h after a single LPS intratracheal instillation. Histopathologic examination, wet/dry lung weight ratio, enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, and western blot analyses were performed to evaluate the degree of lung injury and to determine macrophage phenotypes. Histopathologic examination disclosed attenuation of ALI, with reduced alveolar hemorrhage and neutrophilic infiltration in the USW group. Serum levels of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were significantly decreased after USW therapy. Moreover, the messenger RNA (mRNA) expressions of TNF-α and IL-1β were significantly decreased in the USW group, whereas the mRNA expression of Arginase 1 (Arg1) and the protein expression of mannose receptor significantly increased in comparison with the untreated ALI group. We conclude that USW therapy may attenuate inflammation in LPS-induced ALI through the modulation of macrophage polarization. © 2021 Bioelectromagnetics Society.

Protective effects of recombinant 53-kDa protein of Trichinella spiralis on acute lung injury in mice via alleviating lung pyroptosis by promoting M2 macrophage polarization

Trichinella spiralis represents an effective treatment for autoimmune and inflammatory diseases. The effects of recombinant T. spiralis (TS) 53-kDa protein (rTsP53) on acute lung injury (ALI) remain unclear. Here, mice were divided randomly into a control group, LPS group, and rTsP53 + LPS group. ALI was induced in BALB/c mice by LPS (10 mg/kg) injected via the tail vein. rTsP53 (200 µl; 0.4 μg/μl) was injected subcutaneously three times at an interval of 5 d before inducing ALI in the rTsP53+LPS group. Lung pathological score, the ratio and markers of classic activated macrophages (M1) and alternatively activated macrophages (M2), cytokine profiles in alveolar lavage fluid, and pyroptosis protein expression in lung tissue were investigated. RTsP53 decreased lung pathological score. Furthermore, rTsP53 suppressed inflammation by increasing IL-4, IL-10, and IL-13. There was an increase in alveolar M2 macrophage numbers, with an increase in CD206 and arginase-1-positive cells and a decrease in alveolar M1 markers such as CD197 and iNOS. In addition, the polarization of M2 macrophages induced by rTsP53 treatment could alleviate ALI by suppressing lung pyroptosis. RTsP53 was identified as a potential agent for treating LPS-induced ALI via alleviating lung pyroptosis by promoting M2 macrophage polarization.

Treatment with an Anti-CX3CL1 Antibody Suppresses M1 Macrophage Infiltration in Interstitial Lung Disease in SKG Mice

CX3C Motif Chemokine Ligand 1 (CX3CL1; fractalkine) has been implicated in the pathogenesis of rheumatoid arthritis (RA) and its inhibition was found to attenuate arthritis in mice as well as in a clinical trial. Therefore, we investigated the effects of an anti-CX3CL1 monoclonal antibody (mAb) on immune-mediated interstitial lung disease (ILD) in SKG mice, which exhibit similar pathological and clinical features to human RA-ILD. CX3CL1 and CX3C chemokine receptor 1 (CX3CR1), the receptor for CX3CL1, were both expressed in the fibroblastic foci of lung tissue and the number of bronchoalveolar fluid (BALF) cells was elevated in ILD in SKG mice. No significant changes were observed in lung fibrosis or the number of BALF cells by the treatment with anti-CX3CL1 mAb. However, significantly greater reductions were observed in the number of M1 macrophages than in M2 macrophages in the BALF of treated mice. Furthermore, CX3CR1 expression levels were significantly higher in M1 macrophages than in M2 macrophages. These results suggest the stronger inhibitory effects of the anti-CX3CL1 mAb treatment against the alveolar infiltration of M1 macrophages than M2 macrophages in ILD in SKG mice. Thus, the CX3CL1-CX3CR1 axis may be involved in the infiltration of inflammatory M1 macrophages in RA-ILD.

MiR-124-3p helps to protect against acute respiratory distress syndrome by targeting p65

Background: Acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury that has a high mortality rate and leads to substantial healthcare costs. MicroRNA-124-3p (miR-124-3p) helps to suppress inflammation during a pulmonary injury. However, its mechanism of action is largely unknown, and its role in ARDS remains to be determined.

Methods: Mice and NR8383 cells were exposed to lipopolysaccharides (LPS) to induce ARDS, and their miR-124-3p levels were determined. After a miRNA agomir was administrated to the mice, their pulmonary injuries were evaluated by H&E staining and assays for peripheral inflammatory cytokine levels. The direct interaction between miR-124-3p and p65 was predicted, and then confirmed by a luciferase activity assay. The role played by miRNA-124-3p in regulating p65 expression was further examined by transfection with its agomir, and its role in cell apoptosis was investigated by observing the effects of miRNA overexpression in vitro and in vivo.

Results: After exposure to LPS, there was a consistent decrease in miR-124-3p expression in the lungs of mice and in NR8383 cells. After treatment with the miR-124-3p agomir, the degrees of pulmonary injury (e.g. alveolar hemorrhage and interstitial edema), and the increases in IL-1β, IL-6, and TNF-α levels induced by LPS were significantly attenuated. Overexpression of miR-124-3p in NC8383 cells and lung tissues significantly suppressed LPS-induced p65 expression and cell apoptosis.

Conclusions: These results suggest that miR-124-3p directly targeted p65, and thereby decreased the levels of inflammation and pulmonary injury in a mouse model of ARDS.

Emodin protects against intestinal and lung injury induced by acute intestinal injury by modulating SP-A and TLR4/NF-κB pathway

Objective: Our aim was to investigate the effect of emodin on intestinal and lung injury induced by acute intestinal injury in rats and explore potential molecular mechanisms.

Methods: Healthy male Sprague–Dawley (SD) rats were randomly divided into five groups (n=10, each group): normal group; saline group; acute intestinal injury model group; model + emodin group; model+NF-κB inhibitor pynolidine dithiocarbamate (PDTC) group. Histopathological changes in intestine/lung tissues were observed by Hematoxylin and Eosin (H&E) and terminal deoxynucleotidyl transferase biotin-dUTP nick-end labeling (TUNEL) staining. Serum IKBα, p-IKBα, surfactant protein-A (SP-A) and toll-like receptor 4 (TLR4) levels were examined using enzyme-linked immunosorbent assay (ELISA). RT-qPCR was performed to detect the mRNA expression levels of IKBα, SP-A and TLR4 in intestine/lung tissues. Furthermore, the protein expression levels of IKBα, p-IKBα, SP-A and TLR4 were detected by Western blot.

Results: The pathological injury of intestinal/lung tissues was remarkedly ameliorated in models treated with emodin and PDTC. Furthermore, the intestinal/lung injury scores were significantly decreased after emodin or PDTC treatment. TUNEL results showed that both emodin and PDTC treatment distinctly attenuated the apoptosis of intestine/lung tissues induced by acute intestinal injury. At the mRNA level, emodin significantly increased the expression levels of SP-A and decreased the expression levels of IKBα and TLR4 in intestine/lung tissues. According to ELISA and Western blot, emodin remarkedly inhibited the expression of p-IKBα protein and elevated the expression of SP-A and TLR4 in serum and intestine/lung tissues induced by acute intestinal injury.

Conclusion: Our findings suggested that emodin could protect against intestinal and lung injury induced by acute intestinal injury by modulating SP-A and TLR4/NF-κB pathway.

Tamoxifen suppresses brain metastasis of estrogen receptor-deficient breast cancer by skewing microglia polarization and enhancing their immune functions

Background

Brain metastasis of breast cancer exhibits exceedingly poor prognosis, and both triple negative (TN) and Her2⁺ subtypes have the highest incidence of brain metastasis. Although estrogen blockers are considered to be ineffective for their treatment, recent evidence indicates that estrogen blockade using tamoxifen showed certain efficacy. However, how estrogen affects brain metastasis of triple negative breast cancer (TNBC) remains elusive.

Methods

To examine the effect of estrogen on brain metastasis progression, nude mice were implanted with brain metastatic cells and treated with either estrogen supplement, tamoxifen, or ovariectomy for estrogen depletion. For clinical validation study, brain metastasis specimens from pre- and post-menopause breast cancer patients were examined for microglia polarization by immunohistochemistry. To examine the estrogen-induced M2 microglia polarization, microglia cells were treated with estrogen, and the M1/M2 microglia polarization was detected by qRT-PCR and FACS. The estrogen receptor-deficient brain metastatic cells, SkBrM and 231BrM, were treated with conditioned medium (CM) derived from microglia that were treated with estrogen in the presence or absence of tamoxifen. The effect of microglia-derived CM on tumor cells was examined by colony formation assay and sphere forming ability.

Results

We found that M2 microglia were abundantly infiltrated in brain metastasis of pre-menopausal breast cancer patients. A similar observation was made in vivo, when we treated mice systemically with estrogen. Blocking of estrogen signaling either by tamoxifen treatment or surgical resection of mice ovaries suppressed M2 microglial polarization and decreased the secretion of C-C motif chemokine ligand 5, resulting in suppression of brain metastasis. The estrogen modulation also suppressed stemness in TNBC cells in vitro. Importantly, estrogen enhanced the expression of signal regulatory protein α on microglia and restricted their phagocytic ability.

Conclusions

Our results indicate that estrogen promotes brain metastasis by skewing polarity of M2 microglia and inhibiting their phagocytic ability, while tamoxifen suppresses brain metastasis by blocking the M2 polarization of microglia and increasing their anti-tumor phagocytic ability. Our results also highlight a potential therapeutic utility of tamoxifen for treating brain metastasis of hormone receptor-deficient breast cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01412-z.

Macrophages in Lung Injury, Repair, and Fibrosis

Fibrosis progression in the lung commonly results in impaired functional gas exchange, respiratory failure, or even death. In addition to the aberrant activation and differentiation of lung fibroblasts, persistent alveolar injury and incomplete repair are the driving factors of lung fibrotic response. Macrophages are activated and polarized in response to lipopolysaccharide- or bleomycin-induced lung injury. The classically activated macrophage (M1) and alternatively activated macrophage (M2) have been extensively investigated in lung injury, repair, and fibrosis. In the present review, we summarized the current data on monocyte-derived macrophages that are recruited to the lung, as well as alveolar resident macrophages and their polarization, pyroptosis, and phagocytosis in acute lung injury (ALI). Additionally, we described how macrophages interact with lung epithelial cells during lung repair. Finally, we emphasized the role of macrophage polarization in the pulmonary fibrotic response, and elucidated the potential benefits of targeting macrophage in alleviating pulmonary fibrosis.

Exosome-based photoacoustic imaging guided photodynamic and immunotherapy for the treatment of pancreatic cancer

Exosomes, which are released from all cells and take part in cell-to-cell communication, have been utilized as drug delivery vehicles in many recent studies. Immunotherapy is an emerging technology which uses patients' innate immune systems. In immunotherapy, immune cells are stimulated through antibodies, the other immune cells and genetic modifications for the purposes of, for instance, cancer therapy. In this study, tumor-derived re-assembled exosome (R-Exo) was simultaneously utilized as both a drug delivery carrier and an immunostimulatory agent. A chlorin e6 photosensitizer was loaded into tumor-derived exosomes during exosomal re-assembly. After this modification, R-Exo retains its original average size and has the same membrane proteins, which allows for targeting of tumor cells. Chlorin e6-loaded R-Exo (Ce6-R-Exo) can be visualized by photoacoustic imaging and can efficiently generate reactive oxygen species inside tumor cells under laser irradiation. In addition, Ce6-R-Exo increased the release of cytokines from immune cells, which indicates that these modified exosomes can be used as an immunotherapeutic agent. In conclusion, we developed a novel strategy that enables photoacoustic imaging-guided photodynamic and immune-combination therapy for the treatment of cancer with tumor-derived Ce6-R-Exo.

IFIH1 Contributes to M1 Macrophage Polarization in ARDS

Accumulated evidence has demonstrated that the macrophage phenotypic switch from M0 to M1 is crucial in the initiation of the inflammatory process of acute respiratory distress syndrome (ARDS). Better insight into the molecular control of M1 macrophages in ARDS may identify potential therapeutic targets. In the current study, 36 candidate genes associated with the severity of ARDS and simultaneously involved in M1-polarized macrophages were first screened through a weighted network algorithm on all gene expression profiles from the 26 ARDS patients and empirical Bayes analysis on the gene expression profiles of macrophages. STAT1, IFIH1, GBP1, IFIT3, and IRF1 were subsequently identified as hub genes according to connectivity degree analysis and multiple external validations. Among these candidate genes, IFIH1 had the strongest connection with ARDS through the RobustRankAggreg algorithm. It was selected as a crucial gene for further investigation. For in vitro validation, the RAW264.7 cell line and BMDMs were transfected with shIFIH1 lentivirus and plasmid expression vectors of IFIH1. Cellular experimental studies further confirmed that IFIH1 was a novel regulator for promoting M1 macrophage polarization. Moreover, gene set enrichment analysis (GSEA) and in vitro validations indicated that IFIH1 regulated M1 polarization by activating IRF3. In addition, previous studies demonstrated that activation of IFIH1-IRF3 was stimulated by viral RNAs or RNA mimics. Surprisingly, the current study found that LPS could also induce IFIH1-IRF3 activation via a MyD88-dependent mechanism. We also found that only IFIH1 expression without LPS or RNA mimic stimulation could not affect IRF3 activation and M1 macrophage polarization. These findings were validated on two types of macrophages, RAW264.7 cells and BMDMs, which expanded the knowledge on the inflammatory roles of IFIH1 and IRF3, suggesting IFIH1 as a potential target for ARDS treatment.