hucMSC Conditioned Medium Ameliorate Lipopolysaccharide-Induced Acute Lung Injury by Suppressing Oxidative Stress and Inflammation via Nrf2/NF-κB Signaling Pathway

Human umbilical cord mesenchymal stem cells-derived exosomes attenuate burn-induced acute lung injury via inhibiting ferroptosis

Our previous study has shown that exosomes derived from human umbilical cord mesenchymal stem cells (hUCMSCs-exo) alleviated burn-induced acute lung injury (ALI). In this study, we explored a novel mechanism by which hUCMSCs-exo contributed to the inhibition of burn-induced ALI. The ALI rat model with severe burn was established for the in vivo experiments, and rats PMVECs were stimulated with the serum from burn-induced ALI rats for the in vitro experiments. The pathological changes of lung tissues were evaluated by HE staining; the cell viability was measured using CCK-8; the iron level and Fe2+ concentration were assessed using Iron Assay Kit and Fe2+ fluorescence detection probe; the mRNA expression of SLC7A11 and GPX4 were measured by qRT-PCR; the protein levels of SLC7A11, GPX4, Nrf2 and HO-1 were detected by western blot. Both the in vivo and in vitro experiments revealed that ferroptosis was significantly induced in burn-induced ALI, which as verified by increased iron level and Fe2+ concentration, and decreased SLC7A11 and GPX4 mRNA and protein levels. Furthermore, both hUCMSCs-exo and Fer-1 (the inhibitor of ferroptosis) alleviated lung inflammation and up-regulated protein levels of Nrf2 and HO-1 in the lung tissues of burn-induced ALI rats. These results suggested that hUCMSCs-exo exhibited a protective role against burn-induced ALI by inhibiting ferroptosis, partly owing to the activation of Nrf2/HO-1 pathway, thus providing a novel therapeutic strategy for burn-induced ALI.

Targeting the AMPK/Nrf2 Pathway: A Novel Therapeutic Approach for Acute Lung Injury

ALI(acute lung injury) is a severe respiratory dysfunction caused by various intrapulmonary and extrapulmonary factors. It is primarily characterized by oxidative stress and affects the integrity of the pulmonary barrier. In severe cases, ALI can progress to ARDS(acute respiratory distress syndrome), a condition that poses a serious threat to the lives of affected patients. To date, the etiological mechanisms underlying ALI remain elusive, and available therapeutic options are quite limited. AMPK(AMP-activated protein kinase), an essential serine/threonine protein kinase, performs a pivotal function in the regulation of cellular energy levels and cellular regulatory mechanisms, including the detection of redox signals and mitigating oxidative stress. Meanwhile, Nrf2(nuclear factor erythroid 2-related factor 2), a critical transcription factor, alleviates inflammation and oxidative responses by interacting with multiple signaling pathways and contributing to the modulation of oxidative enzymes associated with inflammation and programmed cell death. Indeed, AMPK induces the dissociation of Nrf2 from Keap1(kelch-like ECH-associated protein-1) and facilitates its translocation into the nucleus to trigger the transcription of downstream antioxidant genes, ultimately suppressing the expression of inflammatory cells in the lungs. Given their roles, AMPK and Nrf2 hold promise as novel treatment targets for ALI. This study aimed to summarise the current status of research on the AMPK/Nrf2 signaling pathway in ALI, encompassing recently reported natural compounds and drugs that can activate the AMPK/Nrf2 signaling pathway to alleviate lung injury, and provide a theoretical reference for early intervention in lung injury and future research on lung protection.

Therapeutic effect of human umbilical cord mesenchymal stem cells and their conditioned medium on LPS-induced endometritis in mice

AIM

To explore the effect of human umbilical cord mesenchymal stem cells (hUC-MSCs) and their conditioned medium (MSC-CM) in repairing the endometritis mouse model in vivo.

METHODS

Lipopolysaccharide (LPS) was used to induce acute inflammation in endometritis mouse model. Mice were treated in six groups: control group (PBS), model group (LPS), LPS+MSC-CM (6 h) group, LPS+MSC-CM (12 h) group, LPS+MSCs (6 h) group and LPS+MSCs (12 h) group. Morphological and histological changes of mouse uterus were observed, and mouse uterine inflammation index myeloperoxidase (MPO) and related immune index TNF-α, IL-6 and IL-1β levels were detected by ELISA.

RESULTS

There exist remarkable inflammatory response and an obvious increase in the value of MPO, TNF-α, IL-1β and IL-6 in the endometritis mouse model compared with the control group. Morphological and histological appearances were relieved after treated with hUC-MSCs and MSC-CM. Besides, the value of MPO, TNF-α, IL-1β and IL-6 showed different degrees of decline. In comparison with LPS+MSC-CM (12 h) and LPS+MSCs (12 h) group, there was significant decrease in inflammatory indicators in LPS+MSC-CM (6 h) and LPS+MSCs (6 h) group.

CONCLUSIONS

Intrauterine infusion of hUC-MSCs and MSC-CM can alleviate LPS induced endometritis.

Ferrostatin-1 Ameliorated Oxidative Lipid Damage in LPS-induced Acute Lung Injury

INTRODUCTION

Ferroptosis is a new type of regulated cell death that is characterized by the overwhelming iron-dependent accumulation of lethal lipid reactive oxygen species and is involved in various diseases. However, the relationship between ferroptosis and lipopolysaccharide (LPS)-induced acute lung injury (ALI) remains largely unknown.

METHODS

In this study, iron metabolism and ferroptosis-related gene mRNA levels in the lung tissues of LPS-induced ALI mice at different time points were detected. Then, the histological, cytokines production, and iron levels of LPS-induced ALI mice with or without the pretreatment of the ferroptosis inhibitor ferrostatin-1 (Fer-1) were measured after mice received the ferroptosis inhibitor ferrostatin-1 (Fer-1) intraperitoneally before LPS administration. Ferroptosis-related protein (GPX4, NRF2, and DPP4) expression was measured in the in vivo and in vitro ALI model. Finally, ROS accumulation and lipid peroxidation was measured in in vivo and in vitro study.

RESULTS

Our results showed that iron metabolism and ferroptosis-related gene mRNA demonstrated significant variation in LPS-treated pulmonary tissues. The ferroptosis inhibitor Fer-1 markedly attenuated the histologic injuries of the lung tissue and suppressed the production of cytokines in bronchoalveolar lavage fluid (BALF). Fer-1 administration reduced the levels of NRF2 and DPP4 protein induced by the LPS challenge. Furthermore, Fer-1 reversed the tendency of iron metabolism, MDA, SOD, and GSH levels induced by LPS administration in in vivo and in vitro.

CONCLUSIONS

Taken together, ferroptosis inhibition by ferrostatin-1 alleviated acute lung injury through modulating oxidative lipid damages induced by the LPS challenge.

The Immunomodulatory Role of Cell-Free Approaches in SARS-CoV-2-Induced Cytokine Storm-A Powerful Therapeutic Tool for COVID-19 Patients

Currently, there is still no effective and definitive cure for the coronavirus disease 2019 (COVID-19) caused by the infection of the novel highly contagious severe acute respiratory syndrome virus (SARS-CoV-2), whose sudden outbreak was recorded for the first time in China in late December 2019. Soon after, COVID-19 affected not only the vast majority of China's population but the whole world and caused a global health public crisis as a new pandemic. It is well known that viral infection can cause acute respiratory distress syndrome (ARDS) and, in severe cases, can even be lethal. Behind the inflammatory process lies the so-called cytokine storm (CS), which activates various inflammatory cytokines that damage numerous organ tissues. Since the first outbreak of SARS-CoV-2, various research groups have been intensively trying to investigate the best treatment options; however, only limited outcomes have been achieved. One of the most promising strategies represents using either stem cells, such as mesenchymal stem cells (MSCs)/induced pluripotent stem cells (iPSCs), or, more recently, using cell-free approaches involving conditioned media (CMs) and their content, such as extracellular vesicles (EVs) (e.g., exosomes or miRNAs) derived from stem cells. As key mediators of intracellular communication, exosomes carry a cocktail of different molecules with anti-inflammatory effects and immunomodulatory capacity. Our comprehensive review outlines the complex inflammatory process responsible for the CS, summarizes the present results of cell-free-based pre-clinical and clinical studies for COVID-19 treatment, and discusses their future perspectives for therapeutic applications.

The protective effect of natural medicines against excessive inflammation and oxidative stress in acute lung injury by regulating the Nrf2 signaling pathway

Acute lung injury (ALI) is a common critical disease of the respiratory system that progresses into acute respiratory distress syndrome (ARDS), with high mortality, mainly related to pulmonary oxidative stress imbalance and severe inflammation. However, there are no clear and effective treatment strategies at present. Nuclear factor erythroid 2-related factor 2(Nrf2) is a transcription factor that interacts with multiple signaling pathways and regulates the activity of multiple oxidases (NOX, NOS, XO, CYP) related to inflammation and apoptosis, and exhibits antioxidant and anti-inflammatory roles in ALI. Recently, several studies have reported that the active ingredients of natural medicines show protective effects on ALI via the Nrf2 signaling pathway. In addition, they are cheap, naturally available, and possess minimal toxicity, thereby having good clinical research and application value. Herein, we summarized various studies on the protective effects of natural pharmaceutical components such as polyphenols, flavonoids, terpenoids, alkaloids, and polysaccharides on ALI through the Nrf2 signaling pathway and demonstrated existing gaps as well as future perspectives.

Advances in mesenchymal stromal cell therapy for acute lung injury/acute respiratory distress syndrome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) develops rapidly and has high mortality. ALI/ARDS is mainly manifested as acute or progressive hypoxic respiratory failure. At present, there is no effective clinical intervention for the treatment of ALI/ARDS. Mesenchymal stromal cells (MSCs) show promise for ALI/ARDS treatment due to their biological characteristics, easy cultivation, low immunogenicity, and abundant sources. The therapeutic mechanisms of MSCs in diseases are related to their homing capability, multidirectional differentiation, anti-inflammatory effect, paracrine signaling, macrophage polarization, the polarization of the MSCs themselves, and MSCs-derived exosomes. In this review, we discuss the pathogenesis of ALI/ARDS along with the biological characteristics and mechanisms of MSCs in the treatment of ALI/ARDS.

Potential stem cell-Conditioned medium and their derived exosomes versus omeprazole in treatment of experimental model of gastric ulcer

Gastric ulcer is a common frequent clinical problem affecting all age and gender. This work aims to compare between the therapeutic effects of stem cell derived exosomes, stem cells conditioned medium and omeprazole on the healing of gastric ulcer model. Fifty rats were, assigned into 5 groups; control, gastric ulcer, omeprazole-treated, conditioned medium- treated, and exosomes-treated groups. Gastric ulcer was induced by aspirin dissolved in 1% carboxymethyl cellulose at a daily dose of 200 mg/kg for 5 consecutive days. Stomach specimens were obtained for histological, biochemical, and immunohistochemical assessments. The gastric ulcer group revealed widening of the fundic glands lumen containing, exfoliated dead cells. There was a remarkable distortion of the normal histological structure of the gastric mucosa with surface lining epithelial cell sloughing, vascular congestion and inflammatory cell infiltration. Both exosomes and conditioned medium treatments ameliorated almost all of the histopathological changes. Interestingly, the healing effect of exosomes was greater because it restored the histological architecture of gastric mucosa to nearly normal. In conclusion, this work may pave the future for using stem cell derived exosomes as a more convenient and effective adjuvant therapy in gastric ulcer.

Anti-Inflammatory and Anti-Fibrotic Effect of Immortalized Mesenchymal-Stem-Cell-Derived Conditioned Medium on Human Lung Myofibroblasts and Epithelial Cells

Idiopathic pulmonary fibrosis (IPF) is caused by progressive lung tissue impairment due to extended chronic fibrosis, and it has no known effective treatment. The use of conditioned media (CM) from an immortalized human adipose mesenchymal stem cell line could be a promising therapeutic strategy, as it can reduce both fibrotic and inflammatory responses. We aimed to investigate the anti-inflammatory and anti-fibrotic effect of CM on human pulmonary subepithelial myofibroblasts (hPSM) and on A549 pulmonary epithelial cells, treated with pro-inflammatory or pro-fibrotic mediators. CM inhibited the proinflammatory cytokine-induced mRNA and protein production of various chemokines in both hPSMs and A549 cells. It also downregulated the mRNA expression of IL-1α, but upregulated IL-1β and IL-6 mRNA production in both cell types. CM downregulated the pro-fibrotic-induced mRNA expression of collagen Type III and the migration rate of hPSMs, but upregulated fibronectin mRNA production and the total protein collagen secretion. CM's direct effect on the chemotaxis and cell recruitment of immune-associated cells, and its indirect effect on fibrosis through the significant decrease in the migration capacity of hPSMs, makes it a plausible candidate for further development towards a therapeutic treatment for IPF.