Mesenchymal Stem Cells Promoted Lung Wound Repair through Hox A9 during Endotoxemia-Induced Acute Lung Injury

Desflurane alleviates LPS-induced acute lung injury by modulating let-7b-5p/HOXA9 axis

Acute lung injury (ALI) is characterized by acute respiratory failure with tachypnea and widespread alveolar infiltrates, badly affecting patients' health. Desflurane (Des) is effective against lung injury. However, its mechanism in ALI remains unknown. BEAS-2B cells were incubated with lipopolysaccharide (LPS) to construct an ALI cell model. Cell apoptosis was evaluated using flow cytometry. Enzyme-linked immunosorbent assay (ELISA) was employed to examine the levels of inflammatory cytokines. Interactions among let-7b-5p, homeobox A9 (HOXA9), and suppressor of cytokine signaling 2 (SOCS2) were verified using Dual luciferase activity, chromatin immunoprecipitation (ChIP), and RNA pull-down analysis. All experimental data of this study were derived from three repeated experiments. Des treatment improved LPS-induced cell viability, reduced inflammatory cytokine (tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6)) levels, decreased cell apoptosis, down-regulated the pro-apoptotic proteins (Bcl-2-associated X protein (Bax) and cleaved caspase 3) expression, and up-regulated the anti-apoptotic protein B-cell-lymphoma-2 (Bcl-2) expression in LPS-induced BEAS-2B cells. Des treatment down-regulated let-7b-5p expression in LPS-induced BEAS-2B cells. Moreover, let-7b-5p inhibition improved LPS-induced cell injury. let-7b-5p overexpression weakened the protective effects of Des. Mechanically, let-7b-5p could negatively modulate HOXA9 expression. Furthermore, HOXA9 inhibited the NF-κB signaling by enhancing SOCS2 transcription. HOXA9 overexpression weakened the promotion of let-7b-5p mimics in LPS-induced cell injury. Des alleviated LPS-induced ALI via regulating let-7b-5p/ HOXA9/NF-κB axis.

MicroRNA-139-5p mediates BMSCs impairment in diabetes by targeting HOXA9/c-Fos

The properties and functions of BMSCs were altered by the diabetic microenvironment, and its mechanism was not very clear. In recent years, the regulation of the function of BMSCs by microRNA has become a research hotspot, meanwhile, HOX genes also have been focused on and involved in multiple functions of stem cells. In this study, we investigated the role of miR-139-5p in diabetes-induced BMSC impairment. Since HOXA9 may be a target gene of miR-139-5p, we speculated that miR-139-5p/HOXA9 might be involved in regulating the biological characteristics and the function of BMSCs in diabetes. We demonstrated that the miR-139-5p expression was increased in BMSCs derived from STZ-induced diabetic rats. MiR-139-5p mimics were able to inhibit cell proliferation, and migration and promoted senescence and apoptosis in vitro. MiR-139-5p induced the down-regulated expression of HOXA9 and c-Fos in BMSCs derived from normal rats. Moreover, miR-139-5p inhibitors reversed the tendency in diabetic-derived BMSCs. Further, gain-and-loss function experiments indicated that miR-139-5p regulated the functions of BMSCs by targeting HOXA9 and c-Fos. In vivo wound model experiments showed that the downregulation of miR-139-5p further promoted the epithelialization and angiogenesis of diabetic BMSC-mediated skin. In conclusion, induction of miR-139-5p upregulation mediated the impairment of BMSCs through the HOXA9/c-Fos pathway in diabetic rats. Therefore, miR-139-5p/HOXA9 might be an important therapeutic target in treating diabetic BMSCs and diabetic complications in the future.

Identification of miRNA signatures associated with radiation-induced late lung injury in mice

Acute radiation exposure of the thorax can lead to late serious, and even life-threatening, pulmonary and cardiac damage. Sporadic in nature, late complications tend to be difficult to predict, which prompted this investigation into identifying non-invasive, tissue-specific biomarkers for the early detection of late radiation injury. Levels of circulating microRNA (miRNA) were measured in C3H and C57Bl/6 mice after whole thorax irradiation at doses yielding approximately 70% mortality in 120 or 180 days, respectively (LD70/120 or 180). Within the first two weeks after exposure, weight gain slowed compared to sham treated mice along with a temporary drop in white blood cell counts. 52% of C3H (33 of 64) and 72% of C57Bl/6 (46 of 64) irradiated mice died due to late radiation injury. Lung and heart damage, as assessed by computed tomography (CT) and histology at 150 (C3H mice) and 180 (C57Bl/6 mice) days, correlated well with the appearance of a local, miRNA signature in the lung and heart tissue of irradiated animals, consistent with inherent differences in the C3H and C57Bl/6 strains in their propensity for developing radiation-induced pneumonitis or fibrosis, respectively. Radiation-induced changes in the circulating miRNA profile were most prominent within the first 30 days after exposure and included miRNA known to regulate inflammation and fibrosis. Importantly, early changes in plasma miRNA expression predicted survival with reasonable accuracy (88-92%). The miRNA signature that predicted survival in C3H mice, including miR-34a-5p, -100-5p, and -150-5p, were associated with pro-inflammatory NF-κB-mediated signaling pathways, whereas the signature identified in C57Bl/6 mice (miR-34b-3p, -96-5p, and -802-5p) was associated with TGF-β/SMAD signaling. This study supports the hypothesis that plasma miRNA profiles could be used to identify individuals at high risk of organ-specific late radiation damage, with applications for radiation oncology clinical practice or in the context of a radiological incident.

LL-37 and its analog FF/CAP18 attenuate neutrophil migration in sepsis-induced acute lung injury

INTRODUCTION

Sepsis can result in acute lung injury. LL-37 is a small cationic host defense peptide involved in anti-inflammatory. In the current study, it was hypothesized that antimicrobial peptide LL-37 could play a protective role in attenuating the progression of sepsis-induced acute lung injury.

METHODS

Forty male C57BL/6 mice were induced into sepsis using cecal ligation and puncture, and subsequently administered with recombinant mouse osteopontin. Peptides LL-37, the LL-37 analog (FF/CAP18, called sLL-37), or normal saline was intravenously administered into septic mice for 20 hours. Then, proinflammatory cytokines (IL-6 and IL-1β), acute lung injury markers (alanine aminotransferase [ALT], aspartate aminotransferase [AST], and lactate dehydrogenase [LDH]), the neutrophil infiltration marker (myeloperoxidase [MPO]), and neutrophil infiltration were detected. Furthermore, the neutrophil migration and expression of migration-related factors (focal adhesion kinase [FAK], ERK, and P38) in differentiated HL-60 cells were detected.

RESULTS

Septic mice had upregulated IL-6, IL-1β, ALT, AST, LDH, MPO, p-FAK, p-ERK, and p-P38, infiltrated neutrophils, and migrated neutrophil-like HL-60 cells. In contrast, the administration of peptide LL-37 and sLL-37 inhibited all these changes. Compared with septic mice, it was found that proinflammatory cytokines, lung injury markers, MPO, and infiltrated neutrophils decreased in mice treated with LL-37 and sLL-37. In addition, the migrated neutrophil-like HL-60 cells and activated p-FAK, p-ERK, and p-P38 proteins were suppressed by LL-37 and sLL-37 treatments.

CONCLUSIONS

Peptide LL-37 and its analog sLL-37 attenuated the progression of sepsis-induced acute lung injury by inhibiting neutrophil infiltration and migration through the FAK, ERK, and P38 pathways.

Identification of Myocardial Telocytes and Bone Marrow Mesenchymal Stem Cells in Mice

OBJECTIVES

The aim of this study was to compare the morphology, immune phenotype, and cytokine profiles between myocardial telocytes (TCs) and bone marrow mesenchymal stem cells (MSCs), and explore the difference between those two types of interstitial cells.

METHODS

TCs and MSCs were cultured in vitro and cell morphology was observed with a light microscope. The expression levels of CD34, c-kit, and vimentin were detected by immunofluorescence, RT-qPCR, and Western blotting in both TCs and MSCs. The related supernatant was collected and total of 49 cytokine profiles were detected by RayBio Mice Cytokine Antibody Array. Significantly different cytokines were further confirmed by ELISA.

RESULTS

TCs have small cellular body and very long prolongations and they were CD34⁺/c-kit⁺/vimentin⁺, whereas MSCs have no telopodes and they were CD34^-/c-kit^- /vimentin⁺. Cytokine profile analysis and ELISA showed that 19 of 49 cytokines were increased dramatically in the supernatant of TCs compared with those of MSCs. Moreover, 9 of 19 cytokines were increased 2-fold at least in the supernatant of TCs compared with those of MSCs. Of 49 cytokines, 30 exhibited no significant changes in the supernatant of TCs compared with those of MSCs.

CONCLUSIONS

Using various technologies, we identified that myocardial TCs and MSCs are significantly different in terms of cell structure and cytokine profiles.

MicroRNA-326 aggravates acute lung injury in septic shock by mediating the NF-κB signaling pathway

Our previous studies have demonstrated that the activation of the nuclear factor-kappa B (NF-κB) signaling pathway contributes to the development of lipopolysaccharide (LPS)-induced acute lung injury (ALI) as well as an inflammatory reaction, and its inhibition may provide future therapeutic values. Thereby, this study aims to explore the effects of miR-326 on inflammatory response and ALI in mice with septic shock via the NF-κB signaling pathway. The study included normal mice and LPS-induced mouse models of septic shock with ALI. Modeled mice were transfected with the blank plasmid, miR-326 mimic, miR-326 inhibitor, si-BCL2A1 and miR-326 inhibitor + si-BCL2A1. Mean arterial pressure (MAP), airway pressure (AP), heart rate (HR) and lung wet dry (W/D) ratio were determined. Serum levels of interleukin (IL)-6, IL-10, IL-1β, and tumor necrosis factor-α (TNF-α) were detected using ELISA. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis were performed to detect the miR-326 expression and expression levels of BCL2A1, related genes of inflammatory response and the NF-κB signaling pathway in lung tissues. Cell viability and apoptosis were measured using the CCK-8 assay and flow cytometry, respectively. Compared to the ALI models and those transfected with blank plasmid, the up-regulated miR-326 expression and silenced BCL2A1 lead to decreased levels of MAP, increased AP, HR and lung W/D, increased serum levels of IL-6, IL-10, IL-1β and TNF-α, increased expressions of IL-6, IL-1β, TNF-α, NF-κB p65 (p-NF-κB p65), and iNOS with decreased expressions of BCL2A1s as well as inhibition of cell viability and enhanced cell apoptosis; the down-regulated miR-326 expression reversed the aforementioned situation. MiR-326 targeting the BCL2A1 gene activated the NF-κB signaling pathway, resulting in aggravated inflammatory response and lung injury of septic shock with ALI in mice.