Fibroblast growth factor-2 alleviates the capillary leakage and inflammation in sepsis

S100A8/A9hi neutrophils induce mitochondrial dysfunction and PANoptosis in endothelial cells via mitochondrial complex I deficiency during sepsis

S100a8/a9, largely released by polymorphonuclear neutrophils (PMNs), belongs to the S100 family of calcium-binding proteins and plays a role in a variety of inflammatory diseases. Although S100a8/a9 has been reported to trigger endothelial cell apoptosis, the mechanisms of S100a8/a9-induced endothelial dysfunction during sepsis require in-depth research. We demonstrate that high expression levels of S100a8/a9 suppress Ndufa3 expression in mitochondrial complex I via downregulation of Nrf1 expression. Mitochondrial complex I deficiency contributes to NAD+-dependent Sirt1 suppression, which induces mitochondrial disorders, including excessive fission and blocked mitophagy, and mtDNA released from damaged mitochondria ultimately activates ZBP1-mediated PANoptosis in endothelial cells. Moreover, based on comprehensive scRNA-seq and bulk RNA-seq analyses, S100A8/A9hi neutrophils are closely associated with the circulating endothelial cell count (a useful marker of endothelial damage), and S100A8 is an independent risk factor for poor prognosis in sepsis patients.

FGF21 ameliorates septic liver injury by restraining proinflammatory macrophages activation through the autophagy/HIF-1α axis

INTRODUCTION

Sepsis, a systemic immune syndrome caused by severe trauma or infection, poses a substantial threat to the health of patients worldwide. The progression of sepsis is heavily influenced by septic liver injury, which is triggered by infection and cytokine storms, and has a significant impact on the tolerance and prognosis of septic patients. The objective of our study is to elucidate the biological role and molecular mechanism of fibroblast growth factor 21 (FGF21) in the process of sepsis.

OBJECTIVES

This study was undertaken in an attempt to elucidate the function and molecular mechanism of FGF21 in therapy of sepsis.

METHODS

Serum concentrations of FGF21 were measured in sepsis patients and septic mice. Liver injury was compared between mice FGF21 knockout (KO) mice and wildtype (WT) mice. To assess the therapeutic potential, recombinant human FGF21 was administered to septic mice. Furthermore, the molecular mechanism of FGF21 was investigated in mice with myeloid-cell specific HIF-1α overexpression mice (LyzM-CreDIO-HIF-1α) and myeloid-cell specific Atg7 knockout mice (Atg7△mye).

RESULTS

Serum level of FGF21 was significantly increased in sepsis patients and septic mice. Through the use of recombinant human FGF21 (rhFGF21) and FGF21 KO mice, we found that FGF21 mitigated septic liver injury by inhibiting the initiation and propagation of inflammation. Treatment with rhFGF21 effectively suppressed the activation of proinflammatory macrophages by promoting macroautophagy/autophagy degradation of hypoxia-inducible factor-1α (HIF-1α). Importantly, the therapeutic effect of rhFGF21 against septic liver injury was nullified in LyzM-CreDIO-HIF-1α mice and Atg7△mye mice.

CONCLUSIONS

Our findings demonstrate that FGF21 considerably suppresses inflammation upon septic liver injury through the autophagy/ HIF-1α axis.

The causal effects of circulating cytokines on sepsis: a Mendelian randomization study

Background

In observational studies, sepsis and circulating levels of cytokines have been associated with unclear causality. This study used Mendelian randomization (MR) to identify the causal direction between circulating cytokines and sepsis in a two-sample study.

Methods

An MR analysis was performed to estimate the causal effect of 41 cytokines on sepsis risk. The inverse-variance weighted random-effects method, the weighted median-based method, and MR-Egger were used to analyze the data. Heterogeneity and pleiotropy were assessed using MR-Egger regression and Cochran's Q statistic.

Results

Genetically predicted beta-nerve growth factor (OR = 1.12, 95% CI [1.037-1.211], P = 0.004) increased the risk of sepsis, while RANTES (OR = 0.92, 95% CI [0.849-0.997], P = 0.041) and fibroblast growth factor (OR = 0.869, 95% CI [0.766-0.986], P = 0.029) reduced the risk of sepsis. These findings were robust in extensive sensitivity analyses. There was no clear association between the other cytokines and sepsis risk.

Conclusion

The findings of this study demonstrate that beta-nerve growth factor, RANTES, and fibroblast growth factor contribute to sepsis risk. Investigations into potential mechanisms are warranted.

Causal association of circulating cytokines with sepsis: a Mendelian randomization study

Background

Observational studies have reported an association between circulating cytokines and sepsis. However, the precise causal relationship between these factors remains unclear. The objective of this study was to explore the causal link between circulating cytokines and sepsis using genetic data within the framework of Mendelian Randomization (MR).

Methods

We performed a two-sample MR analysis to investigate this causality relationship in individuals of European ancestry. The publicly available genome-wide association studies (GWAS) statistics were used. We selected eligible instrumental single nucleotide polymorphisms (SNPs) that were significantly related to the circulating cytokines. Multiple MR analysis approaches were carried out, which included inverse variance weighted (IVW), Weighted Median, MR-Egger, Weighted Mode, Simple Mode, and MR pleiotropy residual sum and outlier (MR-PRESSO) methods.

Results

We found evidence to support the causal role of genetically predicted circulating levels on decreased risk of sepsis, including RANTES (OR = 0.920, 95% CI: 0.849-0.997, P = 0.041) and basic fibroblast growth factor (basic-FGF) (OR = 0.869, 95% CI: 0.766-0.986, P = 0.029). Additionally, MR analysis positive causal association of between beta-nerve growth factor (β-NGF) and sepsis (OR = 1.120, 95% CI: 1.037-1.211, P = 0.004). The results of MR-Egger, Weighted Median, Weighted Mode, and Simple Mode methods were consistent with the IVW estimates. Sensitivity analysis showed no horizontal pleiotropy to bias the causal estimates.

Conclusion

This MR study provides first novel evidence that genetically predicted causal association of circulating levels of RANTES, basic-FGF, and β-NGF with altered sepsis risk. The findings shed light on the potential involvement of these cytokines in sepsis pathogenesis. Although requiring additional confirmation, the results contribute new insights into cytokine mediators in sepsis and suggest promising future research directions.

Ligustilide, a novel SIRT1 agonist, alleviates lipopolysaccharide-induced acute lung injury through deacetylation of NICD

Development and progression of sepsis-induced acute lung injury (ALI) involve apoptosis and oxidative stress in lung epithelial cells. Ligustilide (LIG) is one of the main bioactive constituents derived from the Angelica sinensis. As a novel SIRT1 agonist, LIG owns powerful anti-inflammatory and antioxidative properties, exerting remarkable therapeutic effects on cancers, neurological disorders, and diabetes mellitus. However, whether LIG could protect against lipopolysaccharide (LPS)-induced ALI by activating SIRT1 remains unclear. Mice underwent intratracheal LPS injection to mimic sepsis-induced ALI while MLE-12 cells were treated with LPS for 6 h to establish an in vitro ALI model. At the same time, mice or MLE-12 cells were treated with different doses of LIG to access its pharmacological effect. The results demonstrated that LIG pretreatment could improve LPS-induced pulmonary dysfunction and pathological injury, apart from increasing 7-day survival rate. In addition, LIG pretreatment also decreased inflammation, oxidative stress and apoptosis during LPS-induced ALI. Mechanically, LPS stimulation decreased the expression and activity of SIRT1 but increased the expression of Notch1 and NICD. And LIG could also enhance the interaction between SIRT1 and NICD, thus deacetylating NICD. In vitro experiments also unveiled that EX-527, a selective SIRT1 inhibitor, could abolish LIG-elicited protection in LPS-treated MLE-12 cells. And in SIRT1 knockout mice with ALI, LIG pretreatment also lost its effects on inflammation, apoptosis, and oxidative stress during ALI.

Next-generation biomaterials for dental pulp tissue immunomodulation

OBJECTIVES

The current standard for treating irreversibly damaged dental pulp is root canal therapy, which involves complete removal and debridement of the pulp space and filling with an inert biomaterial. A regenerative approach to treating diseased dental pulp may allow for complete healing of the native tooth structure and enhance the long-term outcome of once-necrotic teeth. The aim of this paper is, therefore, to highlight the current state of dental pulp tissue engineering and immunomodulatory biomaterials properties, identifying exciting opportunities for their synergy in developing next-generation biomaterials-driven technologies.

METHODS

An overview of the inflammatory process focusing on immune responses of the dental pulp, followed by periapical and periodontal tissue inflammation are elaborated. Then, the most recent advances in treating infection-induced inflammatory oral diseases, focusing on biocompatible materials with immunomodulatory properties are discussed. Of note, we highlight some of the most used modifications in biomaterials' surface, or content/drug incorporation focused on immunomodulation based on an extensive literature search over the last decade.

RESULTS

We provide the readers with a critical summary of recent advances in immunomodulation related to pulpal, periapical, and periodontal diseases while bringing light to tissue engineering strategies focusing on healing and regenerating multiple tissue types.

SIGNIFICANCE

Significant advances have been made in developing biomaterials that take advantage of the host's immune system to guide a specific regenerative outcome. Biomaterials that efficiently and predictably modulate cells in the dental pulp complex hold significant clinical promise for improving standards of care compared to endodontic root canal therapy.

Deficiency of endothelial FGFR1 signaling via upregulation of ROCK2 activity aggravated ALI/ARDS

Vascular leakage and inflammation are pathological hallmarks of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Endothelial cells (ECs) serve as a semipermeable barrier and play a key role in disease progression. It is well known that fibroblast growth factor receptor 1 (FGFR1) is required for maintaining vascular integrity. However, how endothelial FGFR1 functions in ALI/ARDS remains obscure. Here, we revealed that conditional deletion of endothelial FGFR1 aggravated LPS-induced lung injury, including inflammation and vascular leakage. Inhibition of its downstream Rho-associated coiled-coil–forming protein kinase 2 (ROCK2) by AAV Vec-tie-shROCK2 or its selective inhibitor TDI01 effectively attenuated inflammation and vascular leakage in a mouse model. In vitro, TNFα-stimulated human umbilical vein endothelial cells (HUVECs) showed decreased FGFR1 expression and increased ROCK2 activity. Furthermore, knockdown of FGFR1 activated ROCK2 and thus promoted higher adhesive properties to inflammatory cells and higher permeability in HUVECs. TDI01 effectively suppressed ROCK2 activity and rescued the endothelial dysfunction. These data demonstrated that the loss of endothelial FGFR1 signaling mediated an increase in ROCK2 activity, which led to an inflammatory response and vascular leakage in vivo and in vitro. Moreover, inhibition of ROCK2 activity by TDI01 provided great value and shed light on clinical translation.

Prospective use of amniotic mesenchymal stem cell metabolite products for tissue regeneration

Chronic disease can cause tissue and organ damage constituting the largest obstacle to therapy which, in turn, reduces patients' quality-adjusted life-year. Degenerative diseases such as osteoporosis, Alzheimer's disease, Parkinson's disease, and infectious conditions such as hepatitis, cause physical injury to organs. Moreover, damage resulting from chronic conditions such as diabetes can also culminate in the loss of organ function. In these cases, organ transplantation constitutes the therapy of choice, despite the associated problems of immunological rejection, potential disease transmission, and high morbidity rates. Tissue regeneration has the potential to heal or replace tissues and organs damaged by age, disease, or trauma, as well as to treat disabilities. Stem cell use represents an unprecedented strategy for these therapies. However, product availability and mass production remain challenges. A novel therapeutic alternative involving amniotic mesenchymal stem cell metabolite products (AMSC-MP) has been developed using metabolites from stem cells which contain cytokines and growth factors. Its potential role in regenerative therapy has recently been explored, enabling broad pharmacological applications including various gastrointestinal, lung, bladder and renal conditions, as well as the treatment of bone wounds, regeneration and skin aging due to its low immunogenicity and anti-inflammatory effects. The various kinds of growth factors present in AMSC-MP, namely bFGF, VEGF, TGF-β, EGF and KGF, have their respective functions and activities. Each growth factor is formed by different proteins resulting in molecules with various physicochemical properties and levels of stability. This knowledge will assist in the manufacture and application of AMSC-MP as a therapeutic agent.

Fibroblast growth factor 2 (FGF2) ameliorates the coagulation abnormalities in sepsis

BACKGROUND

Sepsis is defined as a life-threatening organ dysfunction caused by dysregulation of the host response to infection. There is still a lack of specific treatment for sepsis. Here, we report that Fibroblast growth factor-2 (FGF2) can reduce the mortality of sepsis by ameliorating the coagulation abnormalities.

METHODS

FGF2 was intraperitoneally injected into septic mice induced by lipopolysaccharide (LPS) and then assessed for coagulation response, organ damage and survival. RAW264.7 cells with or without FGF2 pretreating were exposed to LPS, and then changes in coagulation related factors expression and signaling were tested.

RESULTS

The findings showed that intraperitoneal injection of FGF2 inhibited coagulation activity, reduced lung and liver damage, and increased survival in septic mice. In RAW264.7 cells, LPS upregulated the expression of tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1); however, pretreatment with FGF2 prevented this upregulation, while FGF2 knockdown exacerbated TF upregulation. Moreover, FGF2 suppressing the AKT/mTOR/S6K1 signaling pathway in septic mice and RAW264.7 cells stimulated by LPS.

CONCLUSIONS

This study revealed a therapeutic role of FGF2 in ameliorating the coagulation abnormalities during sepsis.

In silico high-throughput screening system for AKT1 activators with therapeutic applications in sepsis acute lung injury

Purpose

AKT1 is an important target in sepsis acute lung injury (SALI). The current study was aim to construct a high-throughput screening (HTS) system based on the ChemDiv database (https://www.chemdiv.com/complete-list/) and use the system to screen for AKT1 activation agents, which may provide clues for the research and development of new drugs to treat SALI.

Methods

Based on the existing X-ray structure of AKT1 and known AKT activators, a large-scale virtual HTS was performed on the ChemDiv database of small molecules by the cascade docking method and demonstrated both accuracy and screening efficiency. Molecular docking and molecular dynamics simulations were used to assess the stability and binding characteristics of the identified small-molecule compounds. The protective effect of the new highly selective compound on SALI were verified both in vitro and in vivo experiments.

Results

The small-molecule compound 7460-0250 was screened out as a specific activator of AKT1. Molecular validation experiments confirmed that compound 7460-0250 specifically promoted the phosphorylation of AKT1 and down-regulated the LPS-induced apoptosis of human umbilical vein endothelial cells (HUVECs) by activating the AKT-mTOR pathway. Up-regulated mTOR was detected to directly interact with Bax to reduce apoptosis. In vivo, compound 7460-0250 could improved survival rate and alleviated lung injury of sepsis mice induced by cecum ligation and puncture (CLP), parallel with the activation of the AKT-mTOR pathway.

Conclusion

Small-molecule compound 7460-0250 was successfully screened and confirmed as a highly selective AKT1 activator, which is a critical target in the development of new therapeutics for SALI.

Knockdown of TRIM27 alleviated sepsis-induced inflammation, apoptosis, and oxidative stress via suppressing ubiquitination of PPARγ and reducing NOX4 expression

BACKGROUND

Sepsis is a global fatal disease and leads to severe lung injury due to dysfunction of inflammation response. TRIM27 is closely related to the diseased with dysfunction of inflammation response. The aim of this study was to clarify the role and mechanism of TRIM27 in sepsis-induced lung injury.

METHODS

The lipopolysaccharide (LPS)-induced septic mouse model was successfully established. The lung injury was evaluated by lung wet/dry (W/D) ratio and hematoxylin-eosin (H&E) staining. The cell apoptosis was evaluated by TUNEL assay. The inflammatory cytokines were measured by quantitative real time-PCR (qRT-PCR) assay and commercial enzyme-linked immunosorbent assay (ELISA). The oxidative stress was assessed by the contents of superoxide dismutase (SOD) and malondialdehyde (MDA), and the expression of dihydroethidium (DHE).

RESULTS

In this study, we demonstrated that TRIM27 was up-regulated in LPS-induced septic mice. In loss-of-function experiments, knockdown of TRIM27 alleviated sepsis-induced lung injury, inflammation, apoptosis, and oxidative stress. More importantly, knockdown of TRIM27 was observed to reduce p-p65/NOX4 expression via suppressing ubiquitination of PPARγ. In rescue experiments, overexpression of NOX4 abolished the effect of sh-TRIM27 on alleviating sepsis-induced inflammation, apoptosis, and oxidative stress.

CONCLUSION

These findings highlighted that knockdown of TRIM27 alleviated sepsis-induced inflammation, oxidative stress and apoptosis via suppressing ubiquitination of PPARγ and reducing NOX4 expression, which supports the potential utility of TRIM27 as a therapeutic target in septic lung injury.

Red Blood Cell Membrane-Camouflaged PLGA Nanoparticles Loaded With Basic Fibroblast Growth Factor for Attenuating Sepsis-Induced Cardiac Injury

Cardiac injury is recognized as a major contributor to septic shock and a major component of the multiple organ dysfunction associated with sepsis. Emerging evidence shows that regulation of the intramyocardial oxidative stress and inflammatory response has a promising prospect. Basic fibroblast growth factor (bFGF) exhibits anti-inflammatory and antioxidant properties. In this study, red blood cell membrane-camouflaged poly (lactide-co-glycolide) nanoparticles were synthesized to deliver bFGF (bFGF-RBC/NP) for sepsis-induced cardiac injury. The in vitro experiments revealed that bFGF-RBC/NP could protect cardiomyocytes from oxidative and inflammatory damage. In addition, the antioxidant and anti-inflammatory properties of bFGF-RBC/NP against cardiac injury were validated using data from in vivo experiments. Collectively, our study used bFGF for the treatment of sepsis-induced cardiac injury and confirmed that bFGF-RBC/NP has therapeutic benefits in the treatment of myocardial dysfunction. This study provides a novel strategy for preventing and treating cardiac injury in sepsis.

Roles of the fibroblast growth factor signal transduction system in tissue injury repair

Following injury, tissue autonomously initiates a complex repair process, resulting in either partial recovery or regeneration of tissue architecture and function in most organisms. Both the repair and regeneration processes are highly coordinated by a hierarchy of interplay among signal transduction pathways initiated by different growth factors, cytokines and other signaling molecules under normal conditions. However, under chronic traumatic or pathological conditions, the reparative or regenerative process of most tissues in different organs can lose control to different extents, leading to random, incomplete or even flawed cell and tissue reconstitution and thus often partial restoration of the original structure and function, accompanied by the development of fibrosis, scarring or even pathogenesis that could cause organ failure and death of the organism. Ample evidence suggests that the various combinatorial fibroblast growth factor (FGF) and receptor signal transduction systems play prominent roles in injury repair and the remodeling of adult tissues in addition to embryonic development and regulation of metabolic homeostasis. In this review, we attempt to provide a brief update on our current understanding of the roles, the underlying mechanisms and clinical application of FGFs in tissue injury repair.

Anagliptin alleviates lipopolysaccharide-induced inflammation, apoptosis and endothelial dysfunction of lung microvascular endothelial cells

It has been reported that dipeptidyl peptidase-4 (DPP4) inhibition protects against acute lung injury (ALI). Anagliptin is a novel selective inhibitor of DPP4 but its role in ALI has not been studied. The present study aimed to investigate the effects of anagliptin on lipopolysaccharide (LPS)-induced human pulmonary microvascular endothelial cell (HPMVEC) injury, as well as its underlying mechanism. HPMVECs were exposed to LPS in the presence or absence of anagliptin co-treatment. MTT assay was used to evaluate cell viability and nitric oxide (NO) production was detected using a commercial kit. DPP4 and pro-inflammatory cytokine expression levels, apoptosis and migration were assessed via reverse transcription-quantitative PCR, western blotting, TUNEL staining and wound healing assay, respectively. Western blot analysis was performed to assess expression levels of proteins involved in NF-κB signaling, cell apoptosis and migration, as well as high mobility group box 1 (HMGB1)/receptor for advanced glycation end products (RAGE). LPS decreased cell viability and NO production, but elevated expression of DPP4 in HPMVECs. LPS promoted pro-inflammatory cytokine expression, NF-κB activation and cell apoptosis, but inhibited cell migration and phosphorylated-AKT/endothelial NO synthase expression. Anagliptin co-treatment significantly restored all of these effects. Mechanistically, the upregulation of HMGB1/RAGE expression induced by LPS was markedly blocked by anagliptin. In conclusion, anagliptin alleviated inflammation, apoptosis and endothelial dysfunction in LPS-induced HPMVECs via modulating HMGB1/RAGE expression. These data provide a basis for use of anagliptin in ALI treatment.

Fibroblast growth factor 2 suppresses the expression of C-C motif chemokine 11 through the c-Jun N-terminal kinase pathway in human dental pulp-derived mesenchymal stem cells

The regulation of the mesenchymal stem cell (MSC) programming mechanism promises great success in regenerative medicine. Tissue regeneration has been associated not only with the differentiation of MSCs, but also with the microenvironment of the stem cell niche that involves various cytokines and immune cells in the tissue regeneration site. In the present study, fibroblast growth factor 2 (FGF2), the principal growth factor for tooth development, dental pulp homeostasis and dentin repair, was reported to affect the expression of cytokines in human dental pulp-derived MSCs. FGF2 significantly inhibited the expression of chemokine C-C motif ligand 11 (CCL11) in a time- and dose-dependent manner in the SDP11 human dental pulp-derived MSC line. This inhibition was diminished following treatment with the AZD4547 FGF receptor (FGFR) inhibitor, indicating that FGF2 negatively regulated the expression of CCL11 in SDP11 cells. Furthermore, FGF2 activated the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinases (JNK) in SDP11 cells. The mechanism of the FGFR-downstream signaling pathway was then studied using the SB203580, U0126 and SP600125 inhibitors for p38 MAPK, ERK1/2, and JNK, respectively. Interestingly, only treatment with SP600125 blocked the FGF2-mediated suppression of CCL11. The present results suggested that FGF2 regulated the expression of cytokines and suppressed the expression of CCL11 via the JNK signaling pathway in human dental pulp-derived MSCs. The present findings could provide important insights into the association of FGF2 and CCL11 in dental tissue regeneration therapy.

IQ Motif-Containing GTPase-Activating Protein 2 Inhibits Breast Cancer Angiogenesis By Suppressing VEGFR2-AKT Signaling

Antiangiogenesis cancer therapies are facing setbacks due to side effects and resistance. Parallel targeting of multiple pathways can help in the development of more effective therapies. This requires the discovery of new molecules that can regulate multiple cellular processes. Our study has recently established the association of reduced IQGAP2 expression in breast cancer with EMT and poor prognosis of the patient. Existing literature indirectly suggests the role of IQGAP2 in angiogenesis that is still unexplored. In this study, we searched the role of IQGAP2 in tumor angiogenesis in a comprehensive manner using cell culture, patients, and animal models. Depletion of IQGAP2 in breast cancer cells increased proliferation, migration, and tubulogenesis of HUVECs. Findings were validated in ex ovo CAM, Matrigel plug and skin wound-healing assays in mouse model, showing that the reduction of IQGAP2 significantly increased angiogenesis. As a confirmation, IHC analysis of the patient's tissues showed a negative correlation of IQGAP2 expression with the microvessel density. Mechanistically, loss of IQGAP2 appeared to activate VEGF-A via ERK activation in tumor cells, which activated the VEGFR2-AKT axis in HUVECs. IMPLICATIONS: The findings of this study suggest the antiangiogenic properties of IQGAP2 in breast cancer. The Dual effect of IQGAP2 on EMT and angiogenesis makes it a potential target for anticancer therapy.

An in situ tissue engineering scaffold with growth factors combining angiogenesis and osteoimmunomodulatory functions for advanced periodontal bone regeneration

Background

The regeneration of periodontal bone defect remains a vital clinical challenge. To date, numerous biomaterials have been applied in this field. However, the immune response and vascularity in defect areas may be key factors that are overlooked when assessing the bone regeneration outcomes of biomaterials. Among various regenerative therapies, the up-to-date strategy of in situ tissue engineering stands out, which combined scaffold with specific growth factors that could mimic endogenous regenerative processes.

Results

Herein, we fabricated a core/shell fibrous scaffold releasing basic fibroblast growth factor (bFGF) and bone morphogenetic protein-2 (BMP-2) in a sequential manner and investigated its immunomodulatory and angiogenic properties during periodontal bone defect restoration. The in situ tissue engineering scaffold (iTE-scaffold) effectively promoted the angiogenesis of periodontal ligament stem cells (PDLSCs) and induced macrophage polarization into pro-healing M2 phenotype to modulate inflammation. The immunomodulatory effect of macrophages could further promote osteogenic differentiation of PDLSCs in vitro. After being implanted into the periodontal bone defect model, the iTE-scaffold presented an anti-inflammatory response, provided adequate blood supply, and eventually facilitated satisfactory periodontal bone regeneration.

Conclusions

Our results suggested that the iTE-scaffold exerted admirable effects on periodontal bone repair by modulating osteoimmune environment and angiogenic activity. This multifunctional scaffold holds considerable promise for periodontal regenerative medicine and offers guidance on designing functional biomaterials.

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00992-4.

Ultrasound and Microbubbles for Targeted Drug Delivery to the Lung Endothelium in ARDS: Cellular Mechanisms and Therapeutic Opportunities

Acute respiratory distress syndrome (ARDS) is characterized by increased permeability of the alveolar–capillary membrane, a thin barrier composed of adjacent monolayers of alveolar epithelial and lung microvascular endothelial cells. This results in pulmonary edema and severe hypoxemia and is a common cause of death after both viral (e.g., SARS-CoV-2) and bacterial pneumonia. The involvement of the lung in ARDS is notoriously heterogeneous, with consolidated and edematous lung abutting aerated, less injured regions. This makes treatment difficult, as most therapeutic approaches preferentially affect the normal lung regions or are distributed indiscriminately to other organs. In this review, we describe the use of thoracic ultrasound and microbubbles (USMB) to deliver therapeutic cargo (drugs, genes) preferentially to severely injured areas of the lung and in particular to the lung endothelium. While USMB has been explored in other organs, it has been under-appreciated in the treatment of lung injury since ultrasound energy is scattered by air. However, this limitation can be harnessed to direct therapy specifically to severely injured lungs. We explore the cellular mechanisms governing USMB and describe various permutations of cargo administration. Lastly, we discuss both the challenges and potential opportunities presented by USMB in the lung as a tool for both therapy and research.

MicroRNA-877-5p alleviates ARDS via enhancing PI3K/Akt path by targeting CDKN1B both in vivo and in vitro

Acute respiratory distress syndrome (ARDS) is a public health problem with high morbidity and mortality worldwide due to lacking known characteristic biomarkers and timely intervention. Pulmonary edema caused by inflammation and pulmonary microvascular endothelial cell disfunction is the main pathophysiological change of ARDS. Circulating microRNAs (miRNAs) are differentially expressed between subjects who did and did not develop ARDS. Many miRNAs have been exemplified to be involved in ARDS and could represent the novel therapeutic targets, but the role of microRNA-877-5p (miR-877-5p) in ARDS and its regulatory mechanisms are still unknown. Herein, we explore the underlying function of miR-877-5p toward anesis of ARDS and addressed that miRNA-877 can reduce the release of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 thus attenuating the damage of pulmonary microvascular endothelial cells (HPMECs). Have further evaluated the protein expression, we detected that miR-877-5p contributed to the relief of ARDS by suppressing Cyclin-dependent kinase inhibitor 1B (CDKN1B), which serves as a regulator of endothelial cell polarization and migration through phosphatidylinositol-3-kinase and AKT (PI3K/Akt) signaling pathway. Besides, we noticed that CDKN1B restrains cell differentiation by inhibiting Cdk2 (cyclin-dependent kinase 2), instead of Cdk4 (cyclin-dependent kinase 4), during which the nuclear translocation of CDKN1B may participate. Together, our works testified that miR-877-5p might suppress inflammatory responses and promote HPMECs regeneration via targeting CDKN1B by modulation of Cdk2 and PI3K/Akt path. These molecules likely modulating ARDS progression may inform biomarkers and therapeutic development.