Akt2 deficiency protects from acute lung injury via alternative macrophage activation and miR-146a induction in mice

Triptolide alleviates acute gouty arthritis caused by monosodium urate crystals by modulating macrophage polarization and neutrophil activity

The present study focused on the efficacy and role of triptolide (TPL) in relieving symptoms of acute gouty arthritis (AGA) in vivo and in vitro. The effects of TPL in AGA were investigated in monosodium urate (MSU)-treated rat ankles, RAW264.7 macrophages, and neutrophils isolated from mouse peritoneal cavity. Observation of pathological changes in the ankle joint of rats. Enzyme-linked immunosorbent assay and real-time quantitative polymerase chain reaction (RT-qPCR) were performed to detect the expression levels of inflammatory factors and chemokines. The levels of the indicators of macrophage M1/M2 polarization, and the mechanistic targets of Akt and rapamycin complex 2, were determined via western blotting and RT-qPCR. The expression levels of CD86 and CD206 were detected using immunohistochemistry. Neutrophil migration was observed via air pouch experiments in vivo and Transwell cell migration assay in vitro. Myeloperoxidase (MPO) and Neutrophil elastase (NE) release was analyzed by via immunohistochemistry and immunofluorescence. The expression levels of beclin-1, LC3B, Bax, Bcl-2, and cleaved caspase-3 in neutrophils were determined via western blotting and immunofluorescence. Neutrophil apoptosis was detected using the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Our results suggest that TPL inhibited inflammatory cell infiltration in rat ankle joints and inflammatory factor and chemokine secretion in rat serum, regulated macrophage polarization through the PI3K/AKT signaling pathway, suppressed inflammatory factor and chemokine expression in neutrophils, and inhibited neutrophil migration, neutrophil extracellular trap formation, transitional autophagy, and apoptosis. This suggests that TPL can prevent and treat MSU-induced AGA by regulating macrophage polarization through the PI3K/Akt pathway and modulating neutrophil activity.

Mechanism of Lian Hua Qing Wen capsules regulates the inflammatory response caused by M1 macrophage based on cellular experiments and computer simulations

PURPOSE

The polarization of macrophages with the resulting inflammatory response play a crucial part in tissue and organ damage due to inflammatory. Study has proved Lian Hua Qing Wen capsules (LHQW) can reduce activation of inflammatory response and damage of tissue derived from the inflammatory reactions. However, the mechanism of LHQW regulates the macrophage-induced inflammatory response is unclear. Therefore, we investigated the mechanism of LHQW regulated the inflammatory response of M1 macrophages by cellular experiments and computer simulations.

METHODS

This study has analysed the targets and mechanisms of macrophage regulating inflammatory response at gene and protein levels through bioinformatics. The monomeric components of LHQW were analyzed by High Performance Liquid Chromatography (HPLC). We established the in vitro cell model by M1 macrophages (Induction of THP-1 cells into M1 macrophages). RT-qPCR and immunofluorescence were used to detect changes in gene and protein levels of key targets after LHQW treatment. Computer simulations were utilized to verify the binding stability of monomeric components and protein targets.

RESULTS

Macrophages had 140,690 gene targets, inflammatory response had 12,192 gene targets, intersection gene targets were 11,772. Key monomeric components (including: Pinocembrin, Fargesone-A, Nodakenin and Bowdichione) of LHQW were screened by HPLC. The results of cellular experiments indicated that LHQW could significantly reduce the mRNA expression of CCR5, CSF2, IFNG and TNF, thereby alleviating the inflammatory response caused by M1 macrophage. The computer simulations further validated the binding stability and conformation of key monomeric components and key protein targets, and IFNG/Nodakenin was able to form the most stable binding conformation for its action.

CONCLUSION

In this study, the mechanism of LHQW inhibits the polarization of macrophages and the resulting inflammatory response was investigated by computer simulations and cellular experiments. We found that LHQW may not only reduce cell damage and death by acting on TNF and CCR5, but also inhibit the immune recognition process and inflammatory response by regulating CSF2 and IFNG to prevent polarization of macrophages. Therefore, these results suggested that LHQW may act through multiple targets to inhibit the polarization of macrophages and the resulting inflammatory response.

Budesonide and N-acetylcysteine inhibit activation of the NLRP3 inflammasome by regulating miR-381 to alleviate acute lung injury caused by the pyroptosis-mediated inflammatory response

Background

The anti-inflammatory effects of budesonide (BUN) and N-acetylcysteine (NAC) attenuate acute lung injury (ALI). The aim of this study was to investigate the effects of combination therapy consisting of BUN and NAC on ALI and the underlying mechanisms.

Methods

In vitro and in vivo models of ALI were generated by LPS induction. Western blotting was used to detect the expression levels of pyroptosis-related proteins and inflammation-related factors, and RT-qPCR was used to detect the expression of miR-381. Cell proliferation and apoptosis were detected by CCK-8 and flow cytometry, respectively. ELISA was used to detect the levels of inflammation-related factors. HE staining was used to detect lung injury.

Results

The results showed that LPS effectively induced pyroptosis in cells and promoted the expression of pyroptosis-related proteins (Caspase1, Gasdermin D and NLRP3) and inflammatory cytokines (TNF-α, IL-6 and IL-1β). The combination of BUN and NAC significantly alleviated LPS-induced pyroptosis and inflammation. In addition, the combination of BUN and NAC effectively promoted miR-381 expression. Transfection of miR-381 mimics effectively alleviated LPS-induced pyroptosis and inflammation, while transfection of miR-381 inhibitors had the opposite effect. miR-381 negatively regulates NLRP3 expression. Treatment with a miR-381 inhibitor or pc-NLRP3 reversed the effects of the combination of BUN and NAC. In a mouse model of ALI, the combination of BUN and NAC effectively improved lung injury, while treatment with a miR-381 inhibitor or pc-NLRP3 effectively reversed this effect.

Conclusion

Overall, this study revealed that BUN + NAC inhibits the activation of NLRP3 by regulating miR-381, thereby alleviating ALI caused by pyroptosis-mediated inflammation.

Emerging role of mesenchymal stem cell-derived exosome microRNA in radiation injury

PURPOSE

Radiation injury (RI) is a common occurrence in malignant tumors patients receiving radiation therapy. While killing tumor cells, normal tissue surrounding the target area is inevitably irradiated at a certain dose, which can cause varying results of radiation injury. Currently, there are limited clinical treatments available for radiation injuries. In recent years, the negative effects of stem cell therapy have been reported more clearly and non-cellular therapies such as exosomes have become a focus of attention for researchers. As a type of vesicle-like substances secreted by mesenchymal stem cells (MSC), MSC derived exosomes (MSC-exo) carry DNA, mRNA, microRNA (miRNAs), specific proteins, lipids, and other active substances involved in intercellular information exchange. miRNAs released by MSC-exo are capable of alleviating and repairing damaged tissues through anti-apoptosis, modulating immune response, regulating inflammatory response and promoting angiogenesis, which indicates that MSC-exo miRNAs have great potential for application in the prevention and treatment of radiation injury. Therefore, it is necessary to explore the underlying therapeutic mechanisms of MSC-exo miRNAs in this process, which may shed new lights on the treatment of radiation injury.

CONCLUSIONS

Increasing evidence confirms that MSC-exo has shown encouraging applications in tissue repair due to the anti-apoptotic, immunoreactive, and pro-angiogenesis effects of the miRNAs it carries as intercellular communication carriers. However, miRNA-based therapeutics are still in their infancy and many practical issues remain to be addressed for clinical applications.

The Use of Extracellular Vesicles in Achilles Tendon Repair: A Systematic Review

Achilles tendon (AT) pathologies are common musculoskeletal conditions that can significantly impair function. Despite various traditional treatments, recovery is often slow and may not restore full functionality. The use of extracellular vesicles (EVs) has emerged as a promising therapeutic option due to their role in cell signaling and tissue regeneration. This systematic review aims to consolidate current in vivo animal study findings on the therapeutic effects of EVs on AT injuries. An extensive literature search was conducted using the PubMed, Scopus, and Embase databases for in vivo animal studies examining the effects of EVs on AT pathologies. The extracted variables included but were not limited to the study design, type of EVs used, administration methods, efficacy of treatment, and proposed therapeutic mechanisms. After screening, 18 studies comprising 800 subjects were included. All but one study reported that EVs augmented wound healing processes in the AT. The most proposed mechanisms through which this occurred were gene regulation of the extracellular matrix (ECM), the enhancement of macrophage polarization, and the delivery of therapeutic microRNAs to the injury site. Further research is warranted to not only explore the therapeutic potential of EVs in the context of AT pathologies, but also to establish protocols for their clinical application.

Extracellular vesicles as carriers for noncoding RNA-based regulation of macrophage/microglia polarization: an emerging candidate regulator for lung and traumatic brain injuries

Macrophage/microglia function as immune defense and homeostatic cells that originate from bone marrow progenitor cells. Macrophage/microglia activation is historically divided into proinflammatory M1 or anti-inflammatory M2 states based on intracellular dynamics and protein production. The polarization of macrophages/microglia involves a pivotal impact in modulating the development of inflammatory disorders, namely lung and traumatic brain injuries. Recent evidence indicates shared signaling pathways in lung and traumatic brain injuries, regulated through non-coding RNAs (ncRNAs) loaded into extracellular vesicles (EVs). This packaging protects ncRNAs from degradation. These vesicles are subcellular components released through a paracellular mechanism, constituting a group of nanoparticles that involve exosomes, microvesicles, and apoptotic bodies. EVs are characterized by a double-layered membrane and are abound with proteins, nucleic acids, and other bioactive compounds. ncRNAs are RNA molecules with functional roles, despite their absence of coding capacity. They actively participate in the regulation of mRNA expression and function through various mechanisms. Recent studies pointed out that selective packaging of ncRNAs into EVs plays a role in modulating distinct facets of macrophage/microglia polarization, under conditions of lung and traumatic brain injuries. This study will explore the latest findings regarding the role of EVs in the progression of lung and traumatic brain injuries, with a specific focus on the involvement of ncRNAs within these vesicles. The conclusion of this review will emphasize the clinical opportunities presented by EV-ncRNAs, underscoring their potential functions as both biomarkers and targets for therapeutic interventions.

Therapeutic potential of mesenchymal stem cell-derived exosomes for allergic airway inflammation

Due to their immunomodulatory capacities, mesenchymal stem cells (MSCs) have been extensively used as therapeutic approaches in cell-based therapy for various inflammatory diseases. Several lines of studies have shown that the most beneficial effects of MSCs are associated with MSC-derived exosomes. Exosomes are nanoscale extracellular vesicles that contain important biomolecules such as RNA, microRNAs (miRNAs), DNA, growth factors, enzymes, chemokines, and cytokines that regulate immune cell functions and parenchymal cell survival. Recently, exosomes, especially MSC-derived exosomes, have been shown to have protective effects in allergic airway inflammation. This review focused on the immune-regulatory potential of MSC-derived exosomes as nanoscale delivery systems in the treatment of allergic airway inflammation.

Tiny Guides, Big Impact: Focus on the Opportunities and Challenges of miR-Based Treatments for ARDS

Acute Respiratory Distress Syndrome (ARDS) is characterized by lung inflammation and increased membrane permeability, which represents the leading cause of mortality in ICUs. Mechanical ventilation strategies are at the forefront of supportive approaches for ARDS. Recently, an increasing understanding of RNA biology, function, and regulation, as well as the success of RNA vaccines, has spurred enthusiasm for the emergence of novel RNA-based therapeutics. The most common types of RNA seen in development are silencing (si)RNAs, antisense oligonucleotide therapy (ASO), and messenger (m)RNAs that collectively account for 80% of the RNA therapeutics pipeline. These three RNA platforms are the most mature, with approved products and demonstrated commercial success. Most recently, miRNAs have emerged as pivotal regulators of gene expression. Their dysregulation in various clinical conditions offers insights into ARDS pathogenesis and offers the innovative possibility of using microRNAs as targeted therapy. This review synthesizes the current state of the literature to contextualize the therapeutic potential of miRNA modulation. It considers the potential for miR-based therapeutics as a nuanced approach that incorporates the complexity of ARDS pathophysiology and the multifaceted nature of miRNA interactions.

An IL-10/DEL-1 axis supports granulopoiesis and survival from sepsis in early life

The limited reserves of neutrophils are implicated in the susceptibility to infection in neonates, however the regulation of neutrophil kinetics in infections in early life remains poorly understood. Here we show that the developmental endothelial locus (DEL-1) is elevated in neonates and is critical for survival from neonatal polymicrobial sepsis, by supporting emergency granulopoiesis. Septic DEL-1 deficient neonate mice display low numbers of myeloid-biased multipotent and granulocyte-macrophage progenitors in the bone marrow, resulting in neutropenia, exaggerated bacteremia, and increased mortality; defects that are rescued by DEL-1 administration. A high IL-10/IL-17A ratio, observed in newborn sepsis, sustains tissue DEL-1 expression, as IL-10 upregulates while IL-17 downregulates DEL-1. Consistently, serum DEL-1 and blood neutrophils are elevated in septic adult and neonate patients with high serum IL-10/IL-17A ratio, and mortality is lower in septic patients with high serum DEL-1. Therefore, IL-10/DEL-1 axis supports emergency granulopoiesis, prevents neutropenia and promotes sepsis survival in early life.

Clinical significance of serum microRNA-146a and inflammatory factors in children with Mycoplasma pneumoniae pneumonia after azithromycin treatment

OBJECTIVE

This study aimed to investigate the clinical significance of serum microRNA-146a and pro-inflammatory factors in children with Mycoplasma pneumoniae pneumonia after azithromycin treatment. microRNA-146a is known to regulate inflammatory responses, and excessive inflammation is a primary characteristic of MPP.

METHODS

Children with MPP received conventional symptomatic therapy along with intravenous administration of azithromycin for one week. Serum levels of microRNA-146a and pro-inflammatory factors were measured using RT-qPCR and ELISA kits, respectively. The correlation between microRNA-146a and pro-inflammatory factors was analyzed by the Pearson method. Pulmonary function indexes were assessed using a pulmonary function analyzer, and their correlation with microRNA-146a and pro-inflammatory factors after treatment was evaluated. Children with MPP were divided into effective and ineffective treatment groups, and the clinical significance of microRNA-146a and pro-inflammatory factors was evaluated using receiver operating characteristic curves and logistic multivariate regression analysis.

RESULTS

Serum microRNA-146a was downregulated in children with MPP but upregulated after azithromycin treatment, contrasting with the trend observed for pro-inflammatory factors. MicroRNA-146a showed a negative correlation with pro-inflammatory cytokines. Pulmonary function parameters were initially reduced in children with MPP, but increased after treatment, showing positive/inverse associations with microRNA-146a and pro-inflammatory factors. Higher microRNA-146a and lower pro-inflammatory factors predicted better efficacy of azithromycin treatment. MicroRNA-146a, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-8 (IL-8), and forced expiratory volume in the first second/forced vital capacity (FEV1/FVC) were identified as independent factors influencing treatment efficacy.

CONCLUSION

Azithromycin treatment in children with MPP upregulates microRNA-146a, downregulates pro-inflammatory factors, and effectively improves pulmonary function.

The potential role of miRNA in regulating macrophage polarization

Macrophage polarization is a dynamic process determining the outcome of various physiological and pathological situations through inducing pro-inflammatory responses or resolving inflammation via exerting anti-inflammatory effects. The miRNAs are epigenetic regulators of different biologic pathways that target transcription factors and signaling molecules to promote macrophage phenotype transition and regulate immune responses. Modulating the macrophage activation, differentiation, and polarization by miRNAs is crucial for immune responses in response to microenvironmental signals and under various physiological and pathological conditions. In term of clinical significance, regulating macrophage polarization via miRNAs could be utilized for inflammation control. Also, understanding the role of miRNAs in macrophage polarization can provide insights into diagnostic strategies associated with dysregulated miRNAs and for developing macrophage-centered therapeutic methods. In this case, targeting miRNAs to further regulate of macrophage polarization may become an efficient strategy for treating immune-associated disorders. The current review investigated and categorized various miRNAs directly or indirectly involved in macrophage polarization by targeting different transcription factors and signaling pathways. In addition, prospects for regulating macrophage polarization via miRNA as a therapeutic choice that could be implicated in various pathological conditions, including cancer or inflammation-mediated injuries, were discussed.

Resveratrol regulates macrophage recruitment and M1 macrophage polarization and prevents corneal allograft rejection in rats

Introduction

Resveratrol is an immune modulator that can reduce M1 macrophage polarization in vitro. Reducing macrophage recruitment and M1 polarization can prevent corneal allograft rejection (CGR). In this study, rat corneal allograft rejection models were established to explore the effects of resveratrol on CGR and macrophages and the underlying mechanisms after corneal transplantation.

Methods

Corneal allograft models were established, and 100 mg/kg resveratrol was injected intraperitoneally. The corneal allografts were assessed clinically using the Holland rejection scoring system, anterior segment photography, and anterior segment optical coherence tomography. Corneal macrophages, pro-inflammatory cytokines, and corneal lymphatic vessels were detected using hematoxylin and eosin staining, immunofluorescence staining, and real-time quantitative polymerase chain reaction (qRT-PCR). Dendritic cells (DCs) in cervical lymph nodes were explored using flow cytometry. RNA sequencing experiments were conducted to identify the mechanisms through which resveratrol affected CGR. The results were verified using Simple Western analysis. Pro-inflammatory cytokines by macrophages in vitro were measured using qRT-PCR and enzyme-linked immunosorbent assays.

Results

Resveratrol significantly prolonged the survival of corneal grafts and reduced graft edema and central corneal thickness. Corneal macrophage recruitment and M1 macrophage polarization decreased significantly after corneal transplantation in the resveratrol group. Resveratrol also reduced pro-inflammatory cytokines in corneal grafts and suppressed the early generation of cornea lymphatic vessels and the recruitment of cornea inflammatory cells 14 days after surgery. Resveratrol decreased the proportion of DCs in ipsilateral cervical lymph nodes. The effect of resveratrol on CGR was related to the phosphatidylinositol 3-kinase/protein kinase-B (PI3K/Akt) pathway. Resveratrol reduced the secretion of pro-inflammatory cytokines by M1 macrophages in vitro.

Conclusion

Our findings suggest that resveratrol can reduce corneal macrophage recruitment and M1 macrophage polarization after corneal transplantation in rats and prevent CGR. The PI3K/Akt pathway may be an important mechanism that warrants further research.

Mesenchymal stromal cells regulate THP-1-differentiated macrophage cytokine production by activating Akt/mammalian target of rapamycin complex 1 pathway

BACKGROUND AIMS

The Akt/mammalian target of rapamycin (mTOR) pathway in macrophages converges inflammatory and metabolic signals from multiple receptors to regulate a cell's survival, metabolism and activation. Although mesenchymal stromal cells (MSCs) are well known to modulate macrophage activation, the effects of MSCs on the Akt/mTOR pathway in macrophages have not been elucidated.

METHODS

We herein investigated whether MSCs affect the Akt/mTOR complex 1 (mTORC1) pathway to regulate macrophage polarization.

RESULTS

Results showed that human bone marrow-derived MSCs induced activation of Akt and its downstream mTORC1 signaling in THP-1-differentiated macrophages in a p62/sequestosome 1-independent manner. Inhibition of Akt or mTORC1 attenuated the effects of MSCs on the suppression of tumor necrosis factor-α and interleukin-12 production and the promotion of interleukin-10 and tumor growth factor-β1 in macrophages stimulated by lipopolysaccharide/ATP. Conversely, activation of Akt or mTORC1 reproduced and potentiated MSC effects on macrophage cytokine production. MSCs with cyclooxygenase-2 knockdown, however, failed to activate the Akt/mTORC1 signaling in macrophages and were less effective in the modulation of macrophage cytokine production than control MSCs.

CONCLUSIONS

These data demonstrate that MSCs control THP-1-differentiated macrophage activation at least partly through upregulation of the Akt/mTORC1 signaling in a cyclooxygenase-2-dependent manner.

Advancements in understanding the role of microRnas in regulating macrophage polarization during acute lung injury

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a critical and life-threatening illness that causes severe dyspnea, and respiratory distress and is often caused by a variety of direct or indirect factors that damage the alveolar epithelium and capillary endothelial cells, leading to inflammation factors and macrophage infiltration. Macrophages play a crucial role in the progression of ALI/ARDS, exhibiting different polarized forms at different stages of the disease that control the disease outcome. MicroRNAs (miRNA) are conserved, endogenous, short non-coding RNAs composed of 18-25 nucleotides that serve as potential markers for many diseases and are involved in various biological processes, including cell proliferation, apoptosis, and differentiation. In this review, we provide a brief overview of miRNA expression in ALI/ARDS and summarize recent research on the mechanism and pathways by which miRNAs respond to macrophage polarization, inflammation, and apoptosis. The characteristics of each pathway are also summarized to provide a comprehensive understanding of the role of miRNAs in regulating macrophage polarization during ALI/ARDS.

Targeting α7-nAChR by galantamine mitigates reserpine-induced fibromyalgia-like symptoms in rats: Involvement of cAMP/PKA, PI3K/AKT, and M1/M2 microglia polarization

Fibromyalgia (FM) is a pain disorder marked by generalized musculoskeletal pain accompanied by depression, fatigue, and sleep disturbances. Galantamine (Gal) is a positive allosteric modulator of neuronal nicotinic acetylcholine receptors (nAChRs) and a reversible inhibitor of cholinesterase. The current study aimed to explore the therapeutic potential of Gal against reserpine (Res)-induced FM-like condition along with investigating the α7-nAChR's role in Gal-mediated effects. Rats were injected with Res (1 mg/kg/day; sc) for 3 successive days then Gal (5 mg/kg/day; ip) was given alone and with the α7-nAChR blocker methyllycaconitine (3 mg/kg/day; ip), for the subsequent 5 days. Galantamine alleviated Res-induced histopathological changes and monoamines depletion in rats' spinal cord. It also exerted analgesic effect along with ameliorating Res-induced depression and motor-incoordination as confirmed by behavioral tests. Moreover, Gal produced anti-inflammatory effect through modulating AKT1/AKT2 and shifting M1/M2 macrophage polarization. The neuroprotective effects of Gal were mediated through activating cAMP/PKA and PI3K/AKT pathways in α7-nAChR-dependent manner. Thus, Gal can ameliorate Res-induced FM-like symptoms and mitigate the associated monoamines depletion, neuroinflammation, oxidative stress, apoptosis, and neurodegeneration through α7-nAChR stimulation, with the involvement of cAMP/PKA, PI3K/AKT, and M1/M2 macrophage polarization.

Efficacy of CU06-1004 via regulation of inflammation and endothelial permeability in LPS-induced acute lung injury

BACKGROUND

Acute lung injury (ALI) is a life-threatening condition that fundamentally results from inflammation and edema in the lung. There are no effective treatments available for clinical use. Previously, we found that as a leakage blocker CU06-1004 prevents endothelial barrier disruption and enhances endothelial cell survival under inflammatory conditions. In this study, we aimed to elucidate the effect of CU06-1004 in terms of prevention of inflammation and endothelial dysfunction in an ALI mouse model.

METHODS

An ALI model was established that included intraperitoneal administration of LPS. Following LPS administration, survival rates and lung wet/dry ratios were assessed. Histological analysis was performed using hematoxylin and eosin staining. Scanning electron microscopy was used to examine alveolar and capillary morphology. Cytokines such as IL-1β, IL-6, and TNF-α were analyzed using an ELISA assay of bronchoalveolar lavage fluid (BALF) and serum. Neutrophil infiltration was observed in BALF using Wright-Giemsa staining, and myeloperoxidase (MPO) activity was assessed. Pulmonary vascular leakage was confirmed using Evans-blue dye, and the expression of junctional proteins was evaluated using immunofluorescent staining. Expression of adhesion molecules was observed using immunofluorescence staining. NF-κB activation was determined using immunohistochemistry and western blot analysis.

RESULTS

Survival rates and pulmonary edema were ameliorated with CU06-1004 treatment. Administration of CU06-1004 normalized histopathological changes induced by LPS, and alveolar-capillary wall thickening was reduced. Compared with the LPS-challenged group, after CU06-1004 treatment, the infiltration of immune cells was decreased in the BALF, and MPO activity in lung tissue was reduced. Similarly, in the CU06-1004 treatment group, pro-inflammatory cytokines were significantly inhibited in both BALF and serum. Evans-blue leakage was reduced, and the expression of junctional proteins was recovered in the CU06-1004 group. Adhesion molecules were downregulated and NF-κB activation was inhibited after CU06-1004 treatment.

CONCLUSIONS

These results suggested that CU06-1004 had a therapeutic effect against LPS-induced ALI via alleviation of the inflammatory response and protection of vascular integrity.

Extracellular Vesicles Derived from Three-Dimensional-Cultured Human Umbilical Cord Blood Mesenchymal Stem Cells Prevent Inflammation and Dedifferentiation in Pancreatic Islets

It is unclear whether extracellular vesicles (EVs) from mesenchymal stem cells (MSCs) have a direct protective effect on pancreatic islets. In addition, whether culturing MSCs in three dimensions (3D) instead of a monolayer (2D) can induce changes in the cargo of EVs that facilitate the polarization of macrophages into an M2 phenotype has not been investigated. We sought to determine whether EVs from MSCs cultured in 3D can prevent inflammation and dedifferentiation in pancreatic islets and, if so, whether the protective effect is superior to that of EVs from 2D MSCs. Human umbilical cord blood- (hUCB-) MSCs cultured in 3D were optimized according to cell density, exposure to hypoxia, and cytokine treatment based on the ability of the hUCB-MSC-derived EVs to induce the M2 polarization of macrophages. Islets isolated from human islet amyloid polypeptide (hIAPP) heterozygote transgenic mice were cultured in serum-deprived conditions with hUCB-MSC-derived EVs. EVs derived from 3D hUCB-MSCs had more abundant microRNAs involved in M2 polarization of macrophages and had an enhanced M2 polarization ability on macrophages, which was optimized when the 3D culture condition was 2.5 × 10⁴ cells per spheroid without preconditioning with hypoxia and cytokine exposure. When islets isolated from hIAPP heterozygote transgenic mice were cultured in serum-deprived conditions with hUCB-MSC-derived EVs, the EVs derived from 3D hUCB-MSCs suppressed the expression of proinflammatory cytokines and caspase-1 in pancreatic islets and increased the proportion of M2-polarized islet-resident macrophages. They improved glucose-stimulated insulin secretion, reduced the expression of Oct4 and NGN3, and induced the expression of Pdx1 and FoxO1. The greater suppression of IL-1β, NLRP3 inflammasome, caspase-1, and Oct4 and induction of Pdx1 and FoxO1 were found in islets cultured with the EVs derived from 3D hUCB-MSCs. In conclusion, EVs derived from 3D hUCB-MSCs optimized for M2 polarization attenuated nonspecific inflammation and preserved β-cell identity of pancreatic islets.

MIR222HG attenuates macrophage M2 polarization and allergic inflammation in allergic rhinitis by targeting the miR146a-5p/TRAF6/NF-κB axis

Although M2 macrophages are involved in the orchestration of type 2 inflammation in allergic diseases, the mechanisms underlying non-coding RNA (ncRNA)-mediated macrophage polarization in allergic rhinitis (AR) have not been systematically understood. Here, we identified long non-coding RNA (lncRNA) MIR222HG as a key regulator of macrophage polarization and revealed its role in AR. Consistent with our bioinformatic analysis of GSE165934 dataset derived from the Gene Expression Omnibus (GEO) database, lncRNA-MIR222HG and murine mir222hg were downregulated in our clinical samples and animal models of AR, respectively. Mir222hg was upregulated in M1 macrophages and downregulated in M2 macrophages. The allergen-ovalbumin facilitated polarization of RAW264.7 cells to the M2 phenotype, accompanied by the downregulation of mir222hg expression in a dose-dependent manner. Mir222hg facilitates macrophage M1 polarization and reverses M2 polarization caused by ovalbumin. Furthermore, mir222hg attenuates macrophage M2 polarization and allergic inflammation in the AR mouse model. Mechanistically, a series of gain- and loss-of-function experiments and rescue experiments were performed to verify the role of mir222hg as a ceRNA sponge that adsorbed miR146a-5p, upregulated Traf6, and activated the IKK/IκB/P65 pathway. Collectively, the data highlight the remarkable role of MIR222HG in the modulation of macrophage polarization and allergic inflammation, as well as its potential role as a novel AR biomarker or therapeutic target.

Acid-sensitive ion channel 1a regulates TNF-α expression in LPS-induced acute lung injury via ERS-CHOP-C/EBPα signaling pathway

BACKGROUND

Acute lung injury (ALI) is the local inflammatory response of the lungs involved in a variety of inflammatory cells. Macrophages are immune cells and inflammatory cells widely distributed in the body. Acid-sensitive ion channel 1a (ASIC1a) is involved in the occurrence of ALI, but the mechanism is still unclear.

METHODS

Kunming mouse were stimulated by Lipopolysaccharides (LPS) to establish ALI model in vivo, and RAW264.7 cells were stimulated by LPS to establish inflammatory model in vitro. Amiloride was used as a blocker of ASIC1a to treat mice, and dexamethasone was used as a positive drug for ALI. After blockers and RNAi blocked or silenced the expression of ASIC1a, the expressions of ASIC1a, endoplasmic reticulum-related proteins GRP78, CHOP, C/EBPα and TNF-α were detected. The Ca²⁺ concentration was measured by a laser confocal microscope. The interaction between CHOP and C/EBPα and the effect of C/EBPα on the activity of TNF-α promoter were detected by immunoprecipitation and luciferase reporter.

RESULTS

The expressions of ASIC1a and TNF-α were increased significantly in LPS group. After the blocker and RNAi blocked or silenced ASIC1a, the expressions of TNF-α, GRP78, CHOP were reduced, and the intracellular Ca²⁺ influx was weakened. The results of immunoprecipitation showed that CHOP and C/EBPα interacted in the macrophages. After silencing CHOP, C/EBPα expression was increased, and TNF-α expression was decreased. The results of the luciferase reporter indicated that C/EBPα directly binds to TNF-α.

CONCLUSION

ASIC1a regulates the expression of TNF-α in LPS-induced acute lung injury via ERS-CHOP-C/EBPα signaling pathway.

Cell volume restriction by mercury chloride reduces M1-like inflammatory response of bone marrow-derived macrophages

Dysregulation of macrophages in the pro-inflammatory (M1) and anti-inflammatory (M2) sub-phenotypes is a crucial element in several inflammation-related diseases and injuries. We investigated the role of aquaporin (AQP) in macrophage polarization using AQP pan-inhibitor mercury chloride (HgCl₂). Lipopolysaccharides (LPSs) induced the expression of AQP-1 and AQP-9 which increased the cell size of bone marrow-derived macrophages. The inhibition of AQPs by HgCl₂ abolished cell size changes and significantly suppressed M1 polarization. HgCl₂ significantly reduced the activation of the nuclear factor kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) pathways and inhibited the production of IL-1β. HgCl₂ attenuated LPS-induced activation of mitochondria and reactive oxygen species production and autophagy was promoted by HgCl₂. The increase in the light chain three II/light chain three I ratio and the reduction in PTEN-induced kinase one expression suggests the recycling of damaged mitochondria and the restoration of mitochondrial activity by HgCl₂. In summary, the present study demonstrates a possible mechanism of the AQP inhibitor HgCl₂ in macrophage M1 polarization through the restriction of cell volume change, suppression of the p38 MAPK/NFκB pathway, and promotion of autophagy.

Role of CD40(L)-TRAF signaling in inflammation and resolution-a double-edged sword

Cardiovascular diseases (CVD) and cardiovascular risk factors are the leading cause of death in the world today. According to the Global Burden of Disease Study, hypertension together with ischemic heart and cerebrovascular diseases is responsible for approximately 40% of all deaths worldwide. The major pathomechanism underlying almost all CVD is atherosclerosis, an inflammatory disorder of the vascular system. Recent large-scale clinical trials demonstrated that inflammation itself is an independent cardiovascular risk factor. Specific anti-inflammatory therapy could decrease cardiovascular mortality in patients with atherosclerosis (increased markers of inflammation). Inflammation, however, can also be beneficial by conferring so-called resolution, a process that contributes to clearing damaged tissue from cell debris upon cell death and thereby represents an essential step for recovery from, e.g., ischemia/reperfusion damage. Based on these considerations, the present review highlights features of the detrimental inflammatory reactions as well as of the beneficial process of immune cell-triggered resolution. In this context, we discuss the polarization of macrophages to either M1 or M2 phenotype and critically assess the role of the CD40L-CD40-TRAF signaling cascade in atherosclerosis and its potential link to resolution. As CD40L can bind to different cellular receptors, it can initiate a broad range of inflammatory processes that may be detrimental or beneficial. Likewise, the signaling of CD40L downstream of CD40 is mainly determined by activation of TRAF1-6 pathways that again can be detrimental or beneficial. Accordingly, CD40(L)-based therapies may be Janus-faced and require sophisticated fine-tuning in order to promote cardioprotection.

The therapeutic effect of adipose-derived stem cells on soft tissue injury after radiotherapy and their value for breast reconstruction

Background

Postmastectomy radiotherapy is considered to be a necessary treatment in the therapy of breast cancer, while it will cause soft tissue damage and complications, which are closely related to the success rate and effectiveness of breast reconstruction. After radiotherapy, cutaneous tissue becomes thin and brittle, and its compliance decreases. Component fat grafting and adipose-derived stem cell therapy are considered to have great potential in treating radiation damage and improving skin compliance after radiotherapy.

Main body

In this paper, the basic types and pathological mechanisms of skin and soft tissue damage to breast skin caused by radiation therapy are described. The 2015–2021 studies related to stem cell therapy in PubMed were also reviewed. Studies suggest that adipose-derived stem cells exert their biological effects mainly through cargoes carried in extracellular vesicles and soluble secreted factors. Compared to traditional fat graft breast reconstruction, ADSC therapy amplifies the effects of stem cells in it. In order to obtain a more purposeful therapeutic effect, proper stem cell pretreatment may achieve more ideal and safe results.

Conclusion

Recent research works about ADSCs and other MSCs mainly focus on curative effects in the acute phase of radiation injury, and there is little research about treatment of chronic phase complications. The efficacy of stem cell therapy on alleviating skin fibrosis and its underlying mechanism require further research.

Pulmonary Delivery of Emerging Antibacterials for Bacterial Lung Infections Treatment

Bacterial infections in the respiratory tract are considered as one of the major challenges to the public health worldwide. Pulmonary delivery is an attractive approach in the management of bacterial respiratory infections with a few inhaled antibiotics approved. However, with the rapid emergence of antibiotic-resistant bacteria, it is necessary to develop new/alternative inhaled antibacterial agents in the post-antibiotic era. A pipeline of novel biological antibacterial agents, including antimicrobial peptides, RNAi therapeutics, and bacteriophages, has emerged to combat bacterial infections with excellent performance. In this review, the causal effects of bacterial infections on the related pulmonary infectious diseases will be firstly introduced. This is followed by an overview on the development of emerging antibacterial therapeutics for managing lung bacterial infections through nebulization/inhalation of dried powders. The obstacles and underlying proposals regarding their clinical transformation are also discussed to seek insights for further development. Research on inhaled therapy of these emerging antibacterials are still in the infancy, but the promising progress warrants further attention.

Akt-2 Is a Potential Therapeutic Target for Disseminated Candidiasis

Akt-1 and Akt-2 are the major isoforms of the serine/threonine Akt family that play a key role in controlling immune responses. However, the involvement of Akt-1 and Akt-2 isoforms in antifungal innate immunity is completely unknown. In this study, we show that Akt2 -/-, but not Akt1 -/-, mice are protected from lethal Candida albicans infection. Loss of Akt-2 facilitates the recruitment of neutrophils and macrophages to the spleen and increases reactive oxygen species expression in these cells. Treating C57BL/6 mice with a specific inhibitor for Akt-2, but not Akt-1, provides protection from lethal C. albicans infection. Our data demonstrate that Akt-2 inhibits antifungal innate immunity by hampering neutrophil and macrophage recruitment to spleens and suppressing oxidative burst, myeloperoxidase activity, and NETosis. We thus describe a novel role for Akt-2 in the regulation of antifungal innate immunity and unveil Akt-2 as a potential target for the treatment of fungal sepsis.

Expression of MicroRNAs in Sepsis-Related Organ Dysfunction: A Systematic Review

Sepsis is a critical condition characterized by increased levels of pro-inflammatory cytokines and proliferating cells such as neutrophils and macrophages in response to microbial pathogens. Such processes lead to an abnormal inflammatory response and multi-organ failure. MicroRNAs (miRNA) are single-stranded non-coding RNAs with the function of gene regulation. This means that miRNAs are involved in multiple intracellular pathways and thus contribute to or inhibit inflammation. As a result, their variable expression in different tissues and organs may play a key role in regulating the pathophysiological events of sepsis. Thanks to this property, miRNAs may serve as potential diagnostic and prognostic biomarkers in such life-threatening events. In this narrative review, we collect the results of recent studies on the expression of miRNAs in heart, blood, lung, liver, brain, and kidney during sepsis and the molecular processes in which they are involved. In reviewing the literature, we find at least 122 miRNAs and signaling pathways involved in sepsis-related organ dysfunction. This may help clinicians to detect, prevent, and treat sepsis-related organ failures early, although further studies are needed to deepen the knowledge of their potential contribution.

IL35 attenuated LPS-induced acute lung injury by regulating macrophage polarization

BACKGROUND

Interleukin 35 (IL35) has been reported to play a role in acute lung injury (ALI); however, the current results regarding the relationship between IL35 and ALI are inconsistent. Therefore, we aimed to further determine the function of IL35 in ALI in mice and the potential mechanism in this paper.

MATERIALS AND METHODS

Hematoxylin-eosin (HE) staining and Masson staining were used to evaluate lung injury in mice. Immunohistochemical staining was used to evaluate the expression of IL35 p35, TLR4 and MD2 and the Bax/Bcl2 and p-P65/P65 ratios. The expression levels of IL35 EBi3, CD68, CD206 and MPO were assessed by immunofluorescence staining. RT-PCR was used to examine the expression levels of IL1β and IL6. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining was performed to detect apoptotic cells.

RESULTS

Overexpression of IL35 alleviated LPS-induced ALI in mice. IL35 overexpression decreased the expression of CD68 and increased the expression of CD206 in mice with ALI. Furthermore, upregulation of IL35 expression obviously reduced the expression of MPO, IL1β and IL6 in the lung tissues of mice with ALI. Mechanistically, IL35 suppressed the TLR4/NFκB-P65 pathway, leading to the promotion of the M1 to M2 macrophage transition and alleviation of inflammation in mice with ALI.

CONCLUSIONS

IL35 relieved LPS-induced inflammation and ALI in mice by regulating M1/M2 macrophage polarization and inhibiting the activation of the TLR4/NFκB-P65 pathway.

Noncoding RNA-mediated macrophage and cancer cell crosstalk in hepatocellular carcinoma

The tumor microenvironment (TME) is a well-recognized system that plays an essential role in tumor initiation, development, and progression. Intense intercellular communication between tumor cells and other cells (especially macrophages) occurs in the TME and is mediated by cell-to-cell contact and/or soluble messengers. Emerging evidence indicates that noncoding RNAs (ncRNAs) are critical regulators of the relationship between cells within the TME. In this review, we provide an update on the regulation of ncRNAs (primarily micro RNAs [miRNAs], long ncRNAs [lncRNAs], and circular RNAs [circRNAs]) in the crosstalk between macrophages and tumor cells in hepatocellular carcinoma (HCC). These ncRNAs are derived from macrophages or tumor cells and act as oncogenes or tumor suppressors, contributing to tumor progression not only by regulating the physiological and pathological processes of tumor cells but also by controlling macrophage infiltration, activation, polarization, and function. Herein, we also explore the options available for clinical therapeutic strategies targeting crosstalk-related ncRNAs to treat HCC. A better understanding of the relationship between macrophages and tumor cells mediated by ncRNAs will uncover new diagnostic biomarkers and pharmacological targets in cancer.

The Regulatory Role of MicroRNAs on Phagocytes: A Potential Therapeutic Target for Chronic Diseases

An effective acute inflammatory response results in the elimination of infectious microorganisms, followed by a smooth transition to resolution and repair. During the inflammatory response, neutrophils play a crucial role in antimicrobial defense as the first cells to reach the site of infection damage. However, if the neutrophils that have performed the bactericidal effect are not removed in time, the inflammatory response will not be able to subside. Anti-inflammatory macrophages are the main scavengers of neutrophils and can promote inflammation towards resolution. MicroRNAs (miRNAs) have great potential as clinical targeted therapy and have attracted much attention in recent years. This paper summarizes the involvement of miRNAs in the process of chronic diseases such as atherosclerosis, rheumatoid arthritis and systemic lupus erythematosus by regulating lipid metabolism, cytokine secretion, inflammatory factor synthesis and tissue repair in two types of cells. This will provide a certain reference for miRNA-targeted treatment of chronic diseases.

Therapeutic implications of exosomes in the treatment of radiation injury

Radiotherapy is one of the main cancer treatments, but it may damage normal tissue and cause various side effects. At present, radioprotective agents used in clinics have side effects such as nausea, vomiting, diarrhea and hypotension, which limit their clinical application. It has been found that exosomes play an indispensable role in radiation injury. Exosomes are lipid bilayer vesicles that carry various bioactive substances, such as proteins, lipids and microRNA (miRNA), that play a key role in cell-to-cell communication and affect tissue injury and repair. In addition, studies have shown that radiation can increase the uptake of exosomes in cells and affect the composition and secretion of exosomes. Here, we review the existing studies and discuss the effects of radiation on exosomes and the role of exosomes in radiation injury, aiming to provide new insights for the treatment of radiation injury.

Ablation of Akt2 and AMPKα2 rescues high fat diet-induced obesity and hepatic steatosis through Parkin-mediated mitophagy

Given the opposing effects of Akt and AMP-activated protein kinase (AMPK) on metabolic homeostasis, this study examined the effects of deletion of Akt2 and AMPKα2 on fat diet-induced hepatic steatosis. Akt2-Ampkα2 double knockout (DKO) mice were placed on high fat diet for 5 months. Glucose metabolism, energy homeostasis, cardiac function, lipid accumulation, and hepatic steatosis were examined. DKO mice were lean without anthropometric defects. High fat intake led to adiposity and decreased respiratory exchange ratio (RER) in wild-type (WT) mice, which were ablated in DKO but not Akt2 -/- and Ampkα2 -/- mice. High fat intake increased blood and hepatic triglycerides and cholesterol, promoted hepatic steatosis and injury in WT mice. These effects were eliminated in DKO but not Akt2 -/- and Ampkα2 -/- mice. Fat diet promoted fat accumulation, and enlarged adipocyte size, the effect was negated in DKO mice. Fat intake elevated fatty acid synthase (FAS), carbohydrate-responsive element-binding protein (CHREBP), sterol regulatory element-binding protein 1 (SREBP1), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), peroxisome proliferator-activated receptor-α (PPARα), PPARγ, stearoyl-CoA desaturase 1 (SCD-1), phosphoenolpyruvate carboxykinase (PEPCK), glucose 6-phosphatase (G6Pase), and diglyceride O-acyltransferase 1 (DGAT1), the effect was absent in DKO but not Akt2 -/- and Ampkα2 -/- mice. Fat diet dampened mitophagy, promoted inflammation and phosphorylation of forkhead box protein O1 (FoxO1) and AMPKα1 (Ser485), the effects were eradicated by DKO. Deletion of Parkin effectively nullified DKO-induced metabolic benefits against high fat intake. Liver samples from obese humans displayed lowered microtubule-associated proteins 1A/1B light chain 3B (LC3B), Pink1, Parkin, as well as enhanced phosphorylation of Akt, AMPK (Ser485), and FoxO1, which were consolidated by RNA sequencing (RNAseq) and mass spectrometry analyses from rodent and human livers. These data suggest that concurrent deletion of Akt2 and AMPKα2 offers resilience to fat diet-induced obesity and hepatic steatosis, possibly through preservation of Parkin-mediated mitophagy and lipid metabolism.

Epigenetic regulation of immunosuppressive tumor-associated macrophages through dysregulated microRNAs

Macrophages are immune cells that play different roles under different physiological conditions. They are present in all tissues where they primarily protect from bacteria and pathogens in addition to assisting in tissue repair. During tumor progression, macrophages can exert contrasting effects based on the M1 vs. M2 polarization. The M2 macrophages support tumor growth through mechanisms that help suppress immune responses and/or circumvent immune-surveillance. A number of such mechanisms such as production of IL-10 and arginase, and expression of PD-L1, V-domain Ig suppressor of T cell activation and B7 family molecule B7-H4 are now believed central to the immunosuppressive effects of tumor-associated macrophages (TAMs). Emerging data has identified epigenetic regulation of these immunosuppressive mechanisms by small non-coding RNAs, the microRNAs (miRNAs). This review discusses the available literature on the subject, including the exosomes mediated transfer of miRNAs between cancer cells and the macrophages within the tumor microenvironment. A number of miRNAs are now believed to be involved in TAMs' production of IL-10 and expression of PD-L1 while the information on such regulation of other immunosuppressive mechanisms is slowly emerging. A better understanding of epigenetic regulation of macrophages-mediated immunosuppressive effect can help identify novel targets for therapy and aid the design of future studies aimed at sensitizing tumors to immune responses.

Analgesic and Anti-Inflammatory Effects of the Synthetic Neurosteroid Analogue BNN27 during CFA-Induced Hyperalgesia

Dehydroepiandrosterone (DHEA), an adrenal and neurosteroid hormone with strong neuroprotective and immunomodulatory properties, and ligand for all high-affinity neurotrophin tyrosine kinase receptors (Trk), also exerts important effects on hyperalgesia. Its synthetic, 17-spiro-epoxy analogue, BNN27, cannot be converted to estrogen or androgen as DHEA; it is a specific agonist of TrkA, the receptor of pain regulator Nerve Growth Factor (NGF), and it conserves the immunomodulatory properties of DHEA. Our study aimed to evaluate the anti-nociceptive and anti-inflammatory properties of BNN27 during Complete Freund’s Adjuvant (CFA)-induced inflammatory hyperalgesia in mice. Hyperalgesia was evaluated using the Hargreaves test. Inflammatory markers such as cytokines, NGF and opioids were measured, additionally to corticosterone and the protein kinase B (AKT) signaling pathway. We showed for the first time that treatment with BNN27 reversed hyperalgesia produced by CFA. The effect of BNN27 involved the inhibition of NGF in the dorsal root ganglia (DRG) and the increased synthesis of opioid peptides and their receptors in the inflamed paw. We also found alterations in the cytokine levels as well as in the phosphorylation of AKT2. Our findings strongly support that BNN27 represents a lead molecule for the development of analgesic and anti-inflammatory compounds with potential therapeutic applications in inflammatory hyperalgesia.

Metabolic Regulation of Macrophage Activation

Macrophages, the central mediators of innate immune responses, being in the first-line of defense, they have to readily respond to pathogenic or tissue damage signals to initiate the inflammatory cascade. Such rapid responses require energy to support orchestrated production of pro-inflammatory mediators and activation of phagocytosis. Being a cell type that is present in diverse environments and conditions, macrophages have to adapt to different nutritional resources. Thus, macrophages have developed plasticity and are capable of utilizing energy at both normoxic and hypoxic conditions and in the presence of varying concentrations of glucose or other nutrients. Such adaptation is reflected on changes in signaling pathways that modulate responses, accounting for the different activation phenotypes observed. Macrophage metabolism has been tightly associated with distinct activation phenotypes within the range of M1-like and M2-like types. In the context of diseases, systemic changes also affect macrophage metabolism, as in diabetes and insulin resistance, which results in altered metabolism and distinct activation phenotypes in the adipose tissue or in the periphery. In the context of solid tumors, tumor-associated macrophages adapt in the hypoxic environment, which results in metabolic changes that are reflected on an activation phenotype that supports tumor growth. Coordination of environmental and pathogenic signals determines macrophage metabolism, which in turn shapes the type and magnitude of the response. Therefore, modulating macrophage metabolism provides a potential therapeutic approach for inflammatory diseases and cancer.

The Role of Macrophages in the Pathogenesis of SARS-CoV-2-Associated Acute Respiratory Distress Syndrome

Macrophages are cells that mediate both innate and adaptive immunity reactions, playing a major role in both physiological and pathological processes. Systemic SARS-CoV-2-associated complications include acute respiratory distress syndrome (ARDS), disseminated intravascular coagulation syndrome, edema, and pneumonia. These are predominantly effects of massive macrophage activation that collectively can be defined as macrophage activation syndrome. In this review we focus on the role of macrophages in COVID-19, as pathogenesis of the new coronavirus infection, especially in cases complicated by ARDS, largely depends on macrophage phenotypes and functionalities. We describe participation of monocytes, monocyte-derived and resident lung macrophages in SARS-CoV-2-associated ARDS and discuss possible utility of cell therapies for its treatment, notably the use of reprogrammed macrophages with stable pro- or anti-inflammatory phenotypes.

Hyperinsulinemia in Obesity, Inflammation, and Cancer

The relative insufficiency of insulin secretion and/or insulin action causes diabetes. However, obesity and type 2 diabetes mellitus can be associated with an absolute increase in circulating insulin, a state known as hyperinsulinemia. Studies are beginning to elucidate the cause-effect relationships between hyperinsulinemia and numerous consequences of metabolic dysfunctions. Here, we review recent evidence demonstrating that hyperinsulinemia may play a role in inflammation, aging and development of cancers. In this review, we will focus on the consequences and mechanisms of excess insulin production and action, placing recent findings that have challenged dogma in the context of the existing body of literature. Where relevant, we elaborate on the role of specific signal transduction components in the actions of insulin and consequences of chronic hyperinsulinemia. By discussing the involvement of hyperinsulinemia in various metabolic and other chronic diseases, we may identify more effective therapeutics or lifestyle interventions for preventing or treating obesity, diabetes and cancer. We also seek to identify pertinent questions that are ripe for future investigation.

Dexmedetomidine Inhibits Acute Lung Injury by Upregulating miR-144 Expression in Mice

The understanding of lung injury’s mechanisms at the molecular level is not fully completed. MicroR-NAs (miRNAs), which are part of different pathophysiological processes, are essential biological regulators that operate by suppressing target genes. A mouse model of acute lung injury (ALI), which is triggered by lipopolysaccharide (LPS), was used to analyze miR-144 level in the ALI mice with or without dexmedetomidine treatment. Inflammation was investigated by the ratio of wet weight’s value to dry weight (W/D) of the lung, the release of cytokines TNF-α, cytokines IL-6, and cytokines IL-1β, and MPO activity. To validate the effect of dexmedetomidine on miR-144, overex-pression and knockdown of miR-144 were applied to treat antagomir144 and agomir144. The result suggested that LPS-triggered ALI was alleviated by dexmedetomidine. miR-144 was downregulated in ALI mice. The knockdown of miR-144 attenuated the protection of dexmedetomidine to acute lung injury. Overexpression of miR-144 attenuated the ALI, which was induced by LPS.

M2 Macrophage-Derived Exosomal miR-590-3p Attenuates DSS-Induced Mucosal Damage and Promotes Epithelial Repair via the LATS1/YAP/ β-Catenin Signalling Axis

BACKGROUND AND AIMS

M2 phenotype macrophages are involved in the resolution of inflammation and intestinal repair. Exosomes are emerging as important mediators of intercellular communication in the mucosal microenvironment.

METHODS

M2 macrophages were transfected with or without miR-590-3p. Exosomes derived from M2 macrophages were isolated and identified. Proliferation and wound healing were tested in vitro and compared between groups. The mechanism involving LATS1, and activation of YAP and β-catenin signalling was investigated by using plasmid transfection, western blotting, immunofluorescence and luciferase reporter assays. The effect of exosomes in vivo was detected in dextran saline sulphate [DSS]-induced murine colitis.

RESULTS

First, we demonstrated that M2 macrophages promoted colonic epithelial cell proliferation in an exosome-dependent manner. Epithelial YAP mediated the effect of M2 macrophage-derived exosomes [M2-exos] in epithelial proliferation. Moreover, miR-590-3p, which was significantly enriched in M2-exos, could be transferred from macrophages into epithelial cells, resulting in the enhanced proliferation and wound healing of epithelial cells. Mechanistically, miR-590-3p suppressed the expression of LATS1 by binding to its coding sequence and subsequently activated the YAP/β-catenin-modulated transcription process to improve epithelial cell wound-healing ability. miR-590-3p also inhibited the induction of pro-inflammatory cytokines, including tumour necrosis factor-α, interleukin-1β [IL-1β] and IL-6. More importantly, repression of miR-590-3p in M2-exos resulted in more severe mucosal damage and impaired colon repair of mice compared with those in M2-exo-treated mice after DSS-induced colitis.

CONCLUSION

M2 macrophage-derived exosomal miR-590-3p reduces inflammatory signals and promotes epithelial regeneration by targeting LATS1 and subsequently activating YAP/β-catenin-regulated transcription, which could offer a new opportunity for clinical therapy for ulcerative colitis.

Epigenetics and Communication Mechanisms in Microglia Activation with a View on Technological Approaches

Microglial cells, the immune cells of the central nervous system (CNS), play a crucial role for the proper brain development and function and in CNS homeostasis. While in physiological conditions, microglia continuously check the state of brain parenchyma, in pathological conditions, microglia can show different activated phenotypes: In the early phases, microglia acquire the M2 phenotype, increasing phagocytosis and releasing neurotrophic and neuroprotective factors. In advanced phases, they acquire the M1 phenotype, becoming neurotoxic and contributing to neurodegeneration. Underlying this phenotypic change, there is a switch in the expression of specific microglial genes, in turn modulated by epigenetic changes, such as DNA methylation, histones post-translational modifications and activity of miRNAs. New roles are attributed to microglial cells, including specific communication with neurons, both through direct cell–cell contact and by release of many different molecules, either directly or indirectly, through extracellular vesicles. In this review, recent findings on the bidirectional interaction between neurons and microglia, in both physiological and pathological conditions, are highlighted, with a focus on the complex field of microglia immunomodulation through epigenetic mechanisms and/or released factors. In addition, advanced technologies used to study these mechanisms, such as microfluidic, 3D culture and in vivo imaging, are presented.

Rosmarinic Acid Regulates Microglial M1/M2 Polarization via the PDPK1/Akt/HIF Pathway Under Conditions of Neuroinflammation

Microglia are resident macrophage-like cells in the central nervous system (CNS). The induction of microglial activation dampens neuroinflammation-related diseases by promoting microglial (re)polarization to the anti-inflammatory (M2) phenotype and can serve as a potential therapeutic approach. Mitochondrial respiration and metabolic reprogramming are required for the anti-inflammatory response of M2 macrophages. However, whether these mitochondrial-dependent pathways are involved in microglial (re)polarization to the anti-inflammatory (M2) phenotype under conditions of lipopolysaccharide (LPS)-induced neuroinflammation remains unclear. Moreover, the mechanisms that coordinate mitochondrial respiration and the functional reprogramming of microglial cells have not been fully elucidated. Rosmarinic acid (RA) possesses antioxidative and anti-inflammatory activities, and we previously reported that RA markedly suppresses LPS-stimulated M1 microglial activation in mice. In this study, we found that RA suppresses M1 microglial polarization and promotes microglial polarization to the M2 phenotype under conditions of neuroinflammation. We identified an increase in mitochondrial respiration and found that metabolic reprogramming is required for the RA-mediated promotion of microglial polarization to the M2 phenotype under LPS-induced neuroinflammation conditions. Hypoxia-inducible factor (HIF) subunits are the key effector molecules responsible for the effects of RA on the restoration of mitochondrial function, metabolic reprogramming, and phenotypic polarization to M2 microglia. The phosphoinositide-dependent protein kinase 1 (PDPK1)/Akt/mTOR pathway is involved in the RA-mediated regulation of HIF expression and increase in M2 marker expression. We propose that the inhibition of PDPK1/Akt/HIFs by RA might be a potential therapeutic approach for inhibiting neuroinflammation through the regulation of microglial M1/M2 polarization. Graphical abstract Schematic of the mechanism through which RA suppresses LPS-induced neuroinflammation by promoting microglial polarization to the M2 phenotype via PDPK1/Akt/HIFs. The bold arrows indicate the direction of the effects of RA (i.e., inhibitory or promoting effects on cytokines or mediators).

Contradictory regulation of macrophages on atherosclerosis based on polarization, death and autophagy

The main pathological feature of atherosclerosis is lipid metabolism disorder and inflammation. Macrophages, as the most important immune cells in the body, run through the beginning and end of disease development. After macrophages overtake the atherosclerosis-susceptible area apolipoprotein low-density lipoprotein ox-LDL, they transform into foam cells that adhere to blood vessels and recruit a large number of pro-inflammatory factors to initiate the disease. Promoting the outflow of lipids in foam cells and alleviating inflammation have become the basic ideas for the study of atherosclerosis treatment strategies. The polarization of macrophages refers to the estimation of the activation of macrophages at a specific point in space and time. Determining the proportion of different macrophage phenotypes in the plaque can help identify delay or prevent disease development. However, the abnormal polarization of macrophages and the accumulation of lipid also affect the growth state of cells to some extent, thus aggravate the influence on plaque area and stability. Besides, overactive or deficient autophagy of macrophages may also lead to cell death and participate in lipid metabolism and inflammation regression. In this paper, the role of macrophages in atherosclerosis was discussed from three aspects: polarization, death, and autophagy.

Depleting microRNA-146a-3p attenuates lipopolysaccharide-induced acute lung injury via up-regulating SIRT1 and mediating NF-κB pathway

OBJECTIVE

The role of microRNAs (miRs) in acute lung injury (ALI) has been discussed. This study is to uncover the effects of miR-146a-3p/Sirtuin-1 (SIRT1)/Nuclear factor-kappa B (NF-κB) axis on ALI.

METHODS

Human normal lung epithelial cell line BEAS-2B was exposed to lipopolysaccharide (LPS) to establish an in vitro model of ALI. NF-κB expression, cell activity, apoptosis, inflammatory factors, oxidative stress indices were detected in LPS-induced BEAS-2B cells after miR-146a-3p was down-regulated or SIRT1 was up-regulated. ALI rat model was established and the NF-κB expression, wet/dry weight (W/D) ratio, pathological changes, pneumonocyte apoptosis, inflammatory factors, oxidative stress indices were detected in ALI rats after miR-146a-3p was down-regulated or SIRT1 was up-regulated. The target relationship between miR-146a-3p and SIRT1 was confirmed.

RESULTS

Reduced SIRT1 and raised miR-146a-3p  were found in LPS-induced BEAS-2B cells and ALI rats. SIRT1-overexpressing or  miR-146a-3p-underexpressing up-regulated NF-κB expression, promoted viability and inhibited apoptosis of LPS-induced BEAS-2B cells in vitro, and increased NF-κB expression, down-regulated the W/D ratio, attenuated pathological changes, suppressed apoptosis, and alleviated inflammatory response and oxidative stress in the lung of ALI rats. MiR-146a-3p directly binds to the 3'UTR of SIRT1 mRNA.

CONCLUSION

Depleting miR-146a-3p improves ALI through up-regulating SIRT1 and mediating NF-κB pathway.

Implications for MicroRNA involvement in the prognosis and treatment of atherosclerosis

MicroRNAs (miRNAs) are important molecules which implicated in various processes, such as differentiation, development, cell survival, cell apoptosis and also cell metabolism. Investigations over decades have revealed that various genes and signaling pathways are implicated in beginning and development of atherosclerosis, several miRNAs being involved in these dysregulated genes and pathways. miRNAs have provided new molecular vision in the context of atherosclerosis. miRNAs are considered as important regulators of cellular migration, differentiation, proliferation, lipid uptake and efflux, as well as cytokine production. Application of miRNAs as a biomarker in diagnosis, prognosis and even therapy is quiet exciting. Although animal researches showed promising results, still some practical difficulties and technical challenges need to be addressed before translation from researches into clinical practices. In this review, we present important data about three critical cells endothelial cell (EC), vascular smooth muscle cell (VSMC), and monocyte/macrophage and regulation of these cells through miRNAs. Furthermore, we discuss about the potential of miRNAs as a prognostic and diagnostic biomarkers, therapeutic opportunities and challenges, and also future perspective.

Alveolar epithelial cell type II as main target of SARS-CoV-2 virus and COVID-19 development via NF-Kb pathway deregulation: A physio-pathological theory

The Corona Virus Disease (COVID-19) pandemic caused by Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) requires a rapid solution and global collaborative efforts in order to define preventive and treatment strategies. One of the major challenges of this disease is the high number of patients needing advanced respiratory support due to the Acute Respiratory Distress Syndrome (ARDS) as the lung is the major - although not exclusive - target of the virus. The molecular mechanisms, pathogenic drivers and the target cell type(s) in SARS-CoV-2 infection are still poorly understood, but the development of a "hyperactive" immune response is proposed to play a role in the evolution of the disease and it is envisioned as a major cause of morbidity and mortality. Here we propose a theory by which the main targets for SARS-CoV-2 are the Type II Alveolar Epithelial Cells and the clinical manifestations of the syndrome are a direct consequence of their involvement. We propose the existence of a vicious cycle by which once alveolar damage starts in AEC II cells, the inflammatory state is supported by macrophage pro-inflammatory polarization (M1), cytokines release and by the activation of the NF-κB pathway. If this theory is confirmed, future therapeutic efforts can be directed to target Type 2 alveolar cells and the molecular pathogenic drivers associated with their dysfunction with currently available therapeutic strategies.

Mesenchymal Stem Cell-Derived Exosomes: Biological Function and Their Therapeutic Potential in Radiation Damage

Radiation-induced damage is a common occurrence in cancer patients who undergo radiotherapy. In this setting, radiation-induced damage can be refractory because the regeneration responses of injured tissues or organs are not well stimulated. Mesenchymal stem cells have become ideal candidates for managing radiation-induced damage. Moreover, accumulating evidence suggests that exosomes derived from mesenchymal stem cells have a similar effect on repairing tissue damage mainly because these exosomes carry various bioactive substances, such as miRNAs, proteins and lipids, which can affect immunomodulation, angiogenesis, and cell survival and proliferation. Although the mechanisms by which mesenchymal stem cell-derived exosomes repair radiation damage have not been fully elucidated, we intend to translate their biological features into a radiation damage model and aim to provide new insight into the management of radiation damage.

MiR-367 alleviates inflammatory injury of microglia by promoting M2 polarization via targeting CEBPA

MiR-367 was reported to regulate inflammatory response of microglia. CCAAT/enhancer-binding protein α (C/EBPA) could mediate microglia polarization. In this study, we explored the possible roles of miR-367 and CEBPA in intracerebral hemorrhage (ICH). ICH and normal specimens were obtained from the tissue adjacent to and distant from hematoma of ICH patients, respectively. Microglia were isolated and identified by immunofluorescence. The isolated microglia were treated with erythrocyte lysate and randomly divided into 8 groups using different transfection reagents. The transfection efficiency of miR-367 was determined by qRT-PCR. The expressions of M1 and M2 microglia markers were detected by Western blotting. The relationship between CEBPA and miR-367 was confirmed by dual luciferase reporter system. Flow cytometry was performed to determine the level of apoptosis in the cells transfected with miR-367 and CEBPA in erythrocyte lysate–treated microglia. We found that miR-367 expression level was downregulated in ICH specimens. Erythrocyte lysate–treated microglia was successfully established using erythrocyte lysate, as decreased miR-367 expression was observed. Overexpression of miR-367 could significantly decrease the expressions of MHC-ІІ, IL-1β, and Bax, reduced apoptosis rate, and increased the expressions of CD206, Bal-2, and Arg-1 in erythrocyte lysate–treated microglia. CEBPA was proved to be a direct target for miR-367, which could inhibit microglia M2 polarization and increase apoptosis rate. However, in the presence of both CEBPA and miR-367 mimic, the protein and mRNA expressions of CEBPA were decreased, leading to promoted microglia M2 polarization and a decreased apoptosis rate. MiR-367 regulates microglia polarization by targeting CEBPA and is expected to alleviate ICH-induced inflammatory injury.

Ferulic acid alleviates lipopolysaccharide-induced acute lung injury through inhibiting TLR4/NF-κB signaling pathway

Ferulic acid (FA) exhibits anti-inflammatory, antidiabetic, antihyperlipidemic, antioxidant, neuroprotective, and antihypertensive effects. This study aimed to determine whether FA could ameliorate lipopolysaccharide (LPS)-induced inflammatory responses and acute lung injury (ALI) in mice. Mice were challenged with LPS intratracheally to induce ALI 1 h after 3 days of FA (25, 50, and 100 mg/kg) or dexamethasone (DEX; 5 mg/kg) administration. The lung tissues and bronchoalveolar lavage fluid (BALF) were collected 12 h after the LPS challenge. Pretreatment with FA or DEX could attenuate lung histopathological change, complement deposition, and lung wet-to-dry weight ratio of mice injured by LPS. Meanwhile, the influx of neutrophils and macrophages, as well as the production of proinflammatory cytokine (tumor necrosis factor-alpha, interleukin 1 beta [IL-1β], and IL-6), in BALF of ALI mice was significantly decreased. Moreover, FA or DEX markedly reversed the LPS-induced elevation of myeloperoxidase activity and monocyte chemoattractant protein-1 level in lung tissues of ALI mice. In addition, the Western blot analysis demonstrated that FA or DEX effectively inhibited the LPS-induced activation of the toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) signaling pathway in lung tissues. The current study suggested that the alleviating effect of FA against LPS-induced ALI might be partially due to the inhibition of the inflammatory response via inactivation of the TLR4/NF-κB signaling pathway.

The Role of MicroRNAs in Acute Respiratory Distress Syndrome and Sepsis, From Targets to Therapies: A Narrative Review

Acute respiratory distress syndrome (ARDS) is a significant cause of morbidity and mortality in the intensive care unit (ICU) and is characterized by lung epithelial and endothelial cell injury, with increased permeability of the alveolar-capillary membrane, leading to pulmonary edema, severe hypoxia, and difficulty with ventilation. The most common cause of ARDS is sepsis, and currently, treatment of ARDS and sepsis has consisted mostly of supportive care because targeted therapies have largely been unsuccessful. The molecular mechanisms behind ARDS remain elusive. Recently, a number of microRNAs (miRNAs) identified through high-throughput screening studies in ARDS patients and preclinical animal models have suggested a role for miRNA in the pathophysiology of ARDS. miRNAs are small noncoding RNAs ranging from 18 to 24 nucleotides that regulate gene expression via inhibition of the target mRNA translation or by targeting complementary mRNA for early degradation. Unsurprisingly, some miRNAs that are differentially expressed in ARDS overlap with those important in sepsis. In addition, circulatory miRNA may be useful as biomarkers or as targets for pharmacologic therapy. This can be revolutionary in a syndrome that has neither a measurable indicator of the disease nor a targeted therapy. While there are currently no miRNA-based therapies targeted for ARDS, therapies targeting miRNA have reached phase II clinical trials for the treatment of a wide range of diseases. Further studies may yield a unique miRNA profile pattern that serves as a biomarker or as targets for miRNA-based pharmacologic therapy. In this review, we discuss miRNAs that have been found to play a role in ARDS and sepsis, the potential mechanism of how particular miRNAs may contribute to the pathophysiology of ARDS, and strategies for pharmacologically targeting miRNA as therapy.

Mesenchymal stem cell-derived extracellular vesicles alter disease outcomes via endorsement of macrophage polarization

Mesenchymal stem cells (MSCs) are adult stromal cells that reside in virtually all postnatal tissues. Due to their regenerative and immunomodulatory capacities, MSCs have attracted growing attention during the past two decades. MSC-derived extracellular vesicles (MSC-EVs) are able to duplicate the effects of their parental cells by transferring functional proteins and genetic materials to recipient cells without cell-to-cell contact. MSC-EVs also target macrophages, which play an essential role in innate immunity, adaptive immunity, and homeostasis. Recent studies have demonstrated that MSC-EVs reduce M1 polarization and/or promote M2 polarization in a variety of settings. In this review, we discuss the mechanisms of macrophage polarization and roles of MSC-EV-induced macrophage polarization in the outcomes of cardiovascular, pulmonary, digestive, renal, and central nervous system diseases. In conclusion, MSC-EVs may become a viable alternative to MSCs for the treatment of diseases in which inflammation and immunity play a critical role.