Conditioned Medium of Bone Marrow Mesenchymal Stem Cells Involved in Acute Lung Injury by Regulating Epithelial Sodium Channels via miR-34c

Abstract

BackgroundOne of the characteristics of acute lung injury (ALI) is severe pulmonary edema, which is closely related to alveolar fluid clearance (AFC). Mesenchymal stem cells (MSCs) secrete a wide range of cytokines, growth factors, and microRNA (miRNAs) through paracrine action to participate in the mechanism of pulmonary inflammatory response, which increase the clearance of edema fluid and promote the repair process of ALI. The epithelial sodium channel (ENaC) is the rate-limiting step in the sodium–water transport and edema clearance in the alveolar cavity; the role of bone marrow-derived MSC-conditioned medium (BMSC-CM) in edema clearance and how miRNAs affect ENaC are still seldom known.MethodsCCK-8 cell proliferation assay was used to detect the effect of BMSC-CM on the survival of alveolar type 2 epithelial (AT2) cells. Real-time polymerase chain reaction (RT-PCR) and western blot were used to detect the expression of ENaC in AT2 cells. The effects of miR-34c on lung fluid absorption were observed in LPS-treated mice in vivo, and the transepithelial short-circuit currents in the monolayer of H441 cells were examined by the Ussing chamber setup. Dual luciferase reporter gene assay was used to detect the target gene of miR-34c.ResultsBMSC-CM could increase the viability of mouse AT2 cells. RT-PCR and western blot results showed that BMSC-CM significantly increased the expression of the γ-ENaC subunit in mouse AT2 cells. MiR-34c could restore the AFC and lung wet/dry weight ratio in the ALI animal model, and Ussing chamber assay revealed that miR-34c enhanced the amiloride-sensitive currents associated with ENaC activity in intact H441 cell monolayers. In addition, we observed a higher expression of miR-34c in mouse AT2 cells administrated with BMSC-CM, and the overexpression or inhibition of miR-34c could regulate the expression of ENaC protein and alter the function of ENaC. Finally, we detected that myristoylated alanine-rich C kinase substrate (MARCKS) may be one of the target genes of miR-34c.ConclusionOur results indicate that BMSC-CM may alleviate LPS-induced ALI through miR-34c targeting MARCKS and regulate ENaC indirectly, which further explores the benefit of paracrine effects of bone marrow-derived MSCs on edematous ALI.

The miR-130a-3p/TGF-βRII Axis Participates in Inhibiting the Differentiation of Fibroblasts Induced by TGF-β1

“…The medium was changed every 2 days. BMSC characterization has been confirmed in our previously published paper (Zhou et al, 2021). At 80% confluence, the medium of BMSCs was changed with DMEM/F12 medium without FBS.…”

Hypoxia Aggravates Inhibition of Alveolar Epithelial Na-Transport by Lipopolysaccharide-Stimulation of Alveolar Macrophages

“…For example, Resolvin conjugates in tissue regeneration 1 (RCTR1), a series of docosahexaenoic acid–derived lipid mediators which can be released from macrophages when externally applied to LPS induced lung injury model upregulates ENaC abundance and improves alveolar fluid clearance [ 47 ]. Mesenchymal stem cells secrete a wide range of cytokines, growth factors, and microRNAs [ 49 ] attenuating edematous lung injury via enhancing γ-ENaC expression, through activating PI3K/AKT signaling [ 36 ]. Therefore, depending on the severity of the lung injury, the cause, and maybe the time elapsed from the onset of the disease, different signaling pathways might be involved in the regulation of alveolar fluid clearance.…”

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

“…For instance, in studies published by Goolaerts et It is well known that the typical pathophysiological features of ALI are lung inflammation, changes in alveolar ion transport, and increased endothelial permeability, often resulting in acute respiratory distress syndrome (ARDS). In all the mentioned research, the administration of MSC-CM resulted in a reduction in lung tissue inflammation and enhancement in wound healing, mainly through activating alveolar macrophage (AM) function; the reduced expression of anti-apoptotic molecules accompanied by increased neutrophil apoptosis; the increased expression of miR-214 and miR-34c; and the downregulation of proinflammatory cytokines, such as IL-1β, IL-6, and TNF-α [62,75,77,[84][85][86]. A similar affirmative result was published by Su et al, who found out that CM obtained from induced pluripotent stem cells (iPSCs) can attenuate endotoxin-induced ALI on mice model via the significant enhancement of endogenous leukemia inhibitory factor production and a decrease in the transendothelial migration of neutrophils [87].…”