Protection of adipose-derived mesenchymal stromal cells during acute lung injury requires autophagy maintained by mTOR

An exploration of the protective effects of Ginsenoside Rb1 against acute lung injury using network pharmacology, molecular docking, molecular dynamics simulations, and in vivo experiments

BACKGROUND

Acute lung injury (ALI) is a severe inflammatory disorder where neutrophils contribute to inflammation and tissue damage by forming neutrophil extracellular traps (NETs). While Ginsenoside Rb1 (Gs-Rb1) has been shown to offer protective effects in ALI, it remains unclear whether its benefits in Lipopolysaccharide (LPS)-induced ALI involve modulation of NETs.

OBJECTIVE

The study aimed to assess the protection of Gs-Rb1 against ALI using bioinformatics analyses and animal experiments.

METHODS

Potential targets of Gs-Rb1 and ALI were identified through several databases and analyzed using protein-protein interaction (PPI) networks, GO and KEGG pathway enrichment, molecular docking, qRT-PCR, and molecular dynamics simulations to pinpoint key targets of Gs-Rb1. The compound's therapeutic effects were further explored in mouse models of LPS-induced ALI.

RESULTS

A total of 90 proteins were identified as shared targets between Gs-Rb1 and ALI. The top 10 targets were selected based on degree values from PPI networks. GO and KEGG enrichment analyses revealed links to 306 biological processes, 29 molecular functions, 63 cellular components, and 148 signaling pathways, suggesting that NET formation plays a central role in the therapeutic effects of Gs-Rb1 on ALI. Molecular docking showed strong binding affinity between Gs-Rb1 and the core targets, while qRT-PCR confirmed significant changes in AKT1 expression following Gs-Rb1 treatment. Molecular dynamics simulations further supported the binding of AKT1 to Gs-Rb1. In LPS-induced mouse models of ALI, Gs-Rb1 treatment attenuated histological damage, reduced the wet/dry mass ratio, and lowered levels of TNF-α, IL-1β, and IL-6. Furthermore, it decreased the fluorescence intensity and protein expression of CitH3, NE, and MPO and downregulated the protein ratios of p-PI3K/PI3K, p-Akt/Akt, and p-mTOR/mTOR.

CONCLUSION

These findings suggest that Gs-Rb1 may alleviate inflammation in ALI by inhibiting NET formation, likely through modulation of the PI3K/AKT/mTOR axis.

Endothelial GSDMD underlies LPS-induced systemic vascular injury and lethality

Endothelial injury destroys endothelial barrier integrity, triggering organ dysfunction and ultimately resulting in sepsis-related death. Considerable attention has been focused on identifying effective targets for inhibiting damage to endothelial cells to treat endotoxemia-induced septic shock. Global gasdermin D (Gsdmd) deletion reportedly prevents death caused by endotoxemia. However, the role of endothelial GSDMD in endothelial injury and lethality in lipopolysaccharide-induced (LPS-induced) endotoxemia and the underlying regulatory mechanisms are unknown. Here, we show that LPS increases endothelial GSDMD level in aortas and lung microvessels. We demonstrated that endothelial Gsdmd deficiency, but not myeloid cell Gsdmd deletion, protects against endothelial injury and death in mice with endotoxemia or sepsis. In vivo experiments suggested that hepatocyte GSDMD mediated the release of high-mobility group box 1, which subsequently binds to the receptor for advanced glycation end products in endothelial cells to cause systemic vascular injury, ultimately resulting in acute lung injury and lethality in shock driven by endotoxemia or sepsis. Additionally, inhibiting endothelial GSDMD activation via a polypeptide inhibitor alleviated endothelial damage and improved survival in a mouse model of endotoxemia or sepsis. These data suggest that endothelial GSDMD is a viable pharmaceutical target for treating endotoxemia and endotoxemia-induced sepsis.

Alleviation of pulmonary fibrosis by the dual PPAR agonist saroglitazar and breast milk mesenchymal stem cells via modulating TGFß/SMAD pathway

Pulmonary fibrosis (PF) is a complex disorder with high morbidity and mortality. Limited efficacies of the available drugs drive researchers to seek for new therapies. Saroglitazar (Saro), a full (PPAR α/γ) agonist, is devoid of known PPAR-mediated adverse effects. Breast milk mesenchymal stem cells (BrMSCs) are contemplated to be the ideal cell type harboring differentiation/anti-inflammatory/immunosuppressive properties. Accordingly, our aims were to investigate the potential roles of Saro and/or BrMSCs in PF and to spot their underlying protective mechanisms. In this study, PF was induced by bleomycin (BLM) via intratracheal instillation. Treatment started 14 days later. Animals were treated with oral saroglitazar (3 mg/kg daily) or intraperitoneal single BrMSCs injection (0.5 ml phosphate buffer saline (PBS) containing 2 × 107 cells) or their combination with same previous doses. At the work end, 24 h following the 6 weeks of treatment period, the levels of oxidative (MDA, SOD), inflammatory (IL-1ß, IL-10), and profibrotic markers (TGF-ß, αSMA) were assessed. The autophagy-related genes (LC3, Beclin) and the expression of PPAR-α/γ and SMAD-3/7 were evaluated. Furthermore, immunohistochemical and histological work were evaluated. Our study revealed marked lung injury influenced by BLM with severe oxidative/inflammatory/fibrotic damage, autophagy inhibition, and deteriorated lung histology. Saro and BrMSCs repaired the lung structure worsened by BLM. Treatments greatly declined the oxidative/inflammatory markers. The pro-fibrotic TGF-ß, αSMA, and SMAD-3 were decreased. Contrarily, autophagy markers were increased. SMAD-7 and PPAR α/γ were activated denoting their pivotal antifibrotic roles. Co-administration of Saro and BrMSCs revealed the top results. Our findings support the study hypothesis that Saro and BrMSCs can be proposed as potential treatments for IPF.

Processing of angiocrine alarmin IL-1α in endothelial cells promotes lung and liver fibrosis

BACKGROUND

Fibrosis results from excessive scar formation after tissue injury. Injured cells release alarmins such as interleukin 1 (IL-1) α and β as primary mediators initiating tissue repair. However, how alarmins from different cell types differentially regulate fibrosis remains to be explored.

METHODS

Here, we used tissue specific knockout strategy to illustrate a unique contribution of endothelial cell-derived IL-1α to lung and liver fibrosis. The two fibrotic animal model triggered by bleomycin and CCl4 were used to study the effects of endothelial paracrine/angiocrine IL-1α in fibrotic progression. Human umbilical vein endothelial cells (HUVEC) were performed to explore the production of angiocrine IL-1α at both transcriptional and post-transcriptional levels in vitro.

RESULTS

We found that endothelial paracrine/angiocrine IL-1α primarily promotes lung and liver fibrosis during the early phase of organ repair. By contrast, myeloid cell-specific ablation of IL-1α in mice resulted in little influence on fibrosis, suggesting the specific pro-fibrotic role of IL-1α from endothelial cell but not macrophage. In vitro study revealed a coordinated regulation of IL-1α production in human primary endothelial cells at both transcriptional and post-transcriptional levels. Specifically, the transcription of IL-1α is regulated by RIPK1, and after caspase-8 (CASP8) cleaves the precursor form of IL-1α, its secretion is triggered by ion channel Pannexin 1 upon CASP8 cleavage.

CONCLUSIONS

Endothelial cell-produced IL-1α plays a unique role in promoting organ fibrosis. Furthermore, the release of this angiocrine alarmin relies on a unique molecular mechanism involving RIPK1, CASP8, and ion channel Pannexin 1.

Effects of nebulized adipose-derived mesenchymal stem cells on acute lung injury following smoke inhalation in sheep

INTRODUCTION

Treatment of ARDS caused by smoke inhalation is challenging with no specific therapies available. The aim of this study was to test the efficacy of nebulized adipose-derived mesenchymal stem cells (ASCs) in a well-characterized, clinically relevant ovine model of smoke inhalation injury.

MATERIAL AND METHODS

Fourteen female Merino sheep were surgically instrumented 5-7 days prior to study. After induction of acute lung injury (ALI) by cooled cotton smoke insufflation into the lungs (under anesthesia and analgesia), sheep were placed on a mechanical ventilator for 48 hrs and monitored for cardiopulmonary hemodynamics in a conscious state. ASCs were isolated from ovine adipose tissue. Sheep were randomly allocated to two groups after smoke injury: 1) ASCs group (n = 6): 10 million ASCs were nebulized into the airway at 1 hr post-injury; and 2) Control group (n = 8): Nebulized with saline into the airways at 1 hr post-injury. ASCs were labeled with green fluorescent protein (GFP) to trace cells within the lung. ASCs viability was determined in bronchoalveolar lavage fluid (BALF).

RESULTS

PaO2/FiO2 in the ASCs group was significantly higher than in the control group (p = 0.001) at 24 hrs. Oxygenation index: (mean airway pressure × FiO2/PaO2) was significantly lower in the ASCs group at 36 hr (p = 0.003). Pulmonary shunt fraction tended to be lower in the ASCs group as compared to the control group. GFP-labelled ASCs were found on the surface of trachea epithelium 48 hrs after injury. The viability of ASCs in BALF was significantly lower than those exposed to the control vehicle solution.

CONCLUSION

Nebulized ASCs moderately improved pulmonary function and delayed the onset of ARDS.

Three-dimensional spheroid formation of adipose-derived stem cells improves the survival of fat transplantation by enhance their therapeutic effect

Adipose-derived stem cells (ADSCs) have important applications in basic research, especially in fat transplantation. Some studies have found that three-dimensional (3D) spheroids formed by mesenchymal stem cells have enhanced therapeutic potential. However, the fundamental basics of this effect are still being discussed. ADSCs were harvested from subcutaneous adipose tissues and 3D spheroids were formed by the automatic aggregation of ADSCs in a non-adhesive 6-well plate. Oxygen glucose deprivation (OGD) was used to simulate the transplantation microenvironment. We found that 3D culture of ADSCs triggered cell autophagy. After inhibiting autophagy by Chloroquine, the rates of apoptosis were increased. When the 3D ADSC-spheroids were re-planked, the number of senescent ADSCs decreased, and the proliferation ability was promoted. In addition, there were more cytokines secreted by 3D ADSC-spheroids including VEGF, IGF-1, and TGF-β. After adding the conditioned medium with human umbilical vein endothelial cells (HUVECs), 3D ADSC-spheroids were more likely to promote migration, and tube formation, stimulating the formation of new blood vessels. Fat grafting experiments in nude mice also showed that 3D ADSC-spheroids enhanced survival and neovascularization of fat grafts. These results suggested that 3D spheroids culturing of ADSCs can increase the therapeutic potential in fat transplantation.

Injectable Decorin/Gellan Gum Hydrogel Encapsulating Adipose-Derived Stem Cells Enhances Anti-Inflammatory Effect in Cartilage Injury via Autophagy Signaling

Adipose-derived stem cells (ADSCs) are employed as a promising alternative in treating cartilage injury. Regulating the inflammatory "fingerprint" of ADSCs to improve their anti-inflammatory properties could enhance therapy efficiency. Herein, a novel injectable decorin/gellan gum hydrogel combined with ADSCs encapsulation for arthritis cartilage treatment is proposed. Decorin/gellan gum hydrogel was prepared according to the previous manufacturing protocol. The liquid-solid form transition of gellan gum hydrogel is perfectly suitable for intra-articular injection. Decorin-enriched matrix showing an immunomodulatory ability to enhance ADSCs anti-inflammatory phenotype under inflammation microenvironment by regulating autophagy signaling. This decorin/gellan gum/ADSCs hydrogel efficiently reverses interleukin-1β-induced cellular injury in chondrocytes. Through a mono-iodoacetate-induced arthritis mice model, the synergistic therapeutic effect of this ADSCs-loaded hydrogel, including inflammation attenuation and cartilage protection, is demonstrated. These results make the decorin/gellan gum hydrogel laden with ADSCs an ideal candidate for treating inflammatory joint disorders.