Eicosapentaenoic Acid Enhances the Effects of Mesenchymal Stromal Cell Therapy in Experimental Allergic Asthma

Natural small molecules synergize mesenchymal stem cells for injury repair in vital organs: a comprehensive review

Mesenchymal stem cells (MSCs) therapy is a highly researched treatment that has the potential to promote immunomodulation and anti-inflammatory, anti-apoptotic, and antimicrobial activities. It is thought that it can enhance internal organ function, reverse tissue remodeling, and achieve significant organ repair and regeneration. However, the limited infusion, survival, and engraftment of transplanted MSCs diminish the effectiveness of MSCs-based therapy. Consequently, various preconditioning methods have emerged as strategies for enhancing the therapeutic effects of MSCs and achieving better clinical outcomes. In particular, the use of natural small molecule compounds (NSMs) as a pretreatment strategy is discussed in this narrative review, with a focus on their roles in regulating MSCs for injury repair in vital internal organs. Additionally, the discussion focuses on the future directions and challenges of transforming mesenchymal stem cell research into clinical applications.

Dietary LPC-Bound n-3 LCPUFA Protects against Neonatal Brain Injury in Mice but Does Not Enhance Stem Cell Therapy

Neonatal hypoxic-ischemic (HI) brain injury is a prominent cause of neurological morbidity, urging the development of novel therapies. Interventions with n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs) and mesenchymal stem cells (MSCs) provide neuroprotection and neuroregeneration in neonatal HI animal models. While lysophosphatidylcholine (LPC)-bound n-3 LCPUFAs enhance brain incorporation, their effect on HI brain injury remains unstudied. This study investigates the efficacy of oral LPC-n-3 LCPUFAs from Lysoveta following neonatal HI in mice and explores potential additive effects in combination with MSC therapy. HI was induced in 9-day-old C57BL/6 mice and Lysoveta was orally supplemented for 7 subsequent days, with or without intranasal MSCs at 3 days post-HI. At 21-28 days post-HI, functional outcome was determined using cylinder rearing, novel object recognition, and open field tasks, followed by the assessment of gray (MAP2) and white (MBP) matter injury. Oral Lysoveta diminished gray and white matter injury but did not ameliorate functional deficits following HI. Lysoveta did not further enhance the therapeutic potential of MSC therapy. In vitro, Lysoveta protected SH-SY5Y neurons against oxidative stress. In conclusion, short-term oral administration of Lysoveta LPC-n-3 LCPUFAs provides neuroprotection against neonatal HI by mitigating oxidative stress injury but does not augment the efficacy of MSC therapy.

Similar Distribution between EPA-containing Phosphatidylcholine and Mesenchymal Stem Marker Positive Cells in the Aortic Wall of Abdominal Aortic Aneurysm Model Rat Fed a Low-EPA Content Diet

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by progressive dilation of the abdominal aorta. Previous studies have suggested that dietary components are closely associated with AAA. Among those dietary components, eicosapentaenoic acid (EPA) is considered to have suppressive effects on AAA. In the AAA wall of AAA model animals bred under EPA-rich condition, the distribution of EPA-containing phosphatidylcholine (EPA-PC) has been reported to be similar to that of the markers of mesenchymal stem cells (MSCs) and M2 macrophages. These data suggest that the suppressive effects of EPA on AAA are related to preferential distribution of specific cells in the aortic wall. However, the distribution of EPA-PC in the AAA wall of AAA model animals fed a diet containing small amounts of EPA, which has not been reported to inhibit AAA, has not yet been explored. In the present study, we visualized the distribution of EPA-PCs in the AAA wall of AAA model animals fed a diet containing small amounts of EPA (1.5% EPA in the fatty acid composition) to elucidate the vasoprotective effects of EPA. Positive areas for markers of MSCs were significantly higher in the region where EPA-PC was abundant compared to the regions where EPA-PC was weakly detected, but not for markers of M2 macrophages, matrix metalloproteinase (MMP)-2, and MMP-9. The distribution of MSC markers was similar to that of EPA-PC but not that of M2 macrophages and MMPs. These data suggest preferential incorporation of EPA into MSCs under the conditions used in this study. The incorporation of EPA into certain cells may differ according to dietary conditions, which affect the development of AAA.

Mesenchymal stromal cell derived extracellular vesicles as a therapeutic tool: immune regulation, MSC priming, and applications to SLE

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by a dysfunction of the immune system. Mesenchymal stromal cell (MSCs) derived extracellular vesicles (EVs) are nanometer-sized particles carrying a diverse range of bioactive molecules, such as proteins, miRNAs, and lipids. Despite the methodological disparities, recent works on MSC-EVs have highlighted their broad immunosuppressive effect, thus driving forwards the potential of MSC-EVs in the treatment of chronic diseases. Nonetheless, their mechanism of action is still unclear, and better understanding is needed for clinical application. Therefore, we describe in this review the diverse range of bioactive molecules mediating their immunomodulatory effect, the techniques and possibilities for enhancing their immune activity, and finally the potential application to SLE.

The MSC-EV-microRNAome: A Perspective on Therapeutic Mechanisms of Action in Sepsis and ARDS

Mesenchymal stromal cells (MSCs) and MSC-derived extracellular vesicles (EVs) have emerged as innovative therapeutic agents for the treatment of sepsis and acute respiratory distress syndrome (ARDS). Although their potential remains undisputed in pre-clinical models, this has yet to be translated to the clinic. In this review, we focused on the role of microRNAs contained in MSC-derived EVs, the EV microRNAome, and their potential contribution to therapeutic mechanisms of action. The evidence that miRNA transfer in MSC-derived EVs has a role in the overall therapeutic effects is compelling. However, several questions remain regarding how to reconcile the stochiometric issue of the low copy numbers of the miRNAs present in the EV particles, how different miRNAs delivered simultaneously interact with their targets within recipient cells, and the best miRNA or combination of miRNAs to use as therapy, potency markers, and biomarkers of efficacy in the clinic. Here, we offer a molecular genetics and systems biology perspective on the function of EV microRNAs, their contribution to mechanisms of action, and their therapeutic potential.

Human macrophage migration inhibitory factor potentiates mesenchymal stromal cell efficacy in a clinically relevant model of allergic asthma

Current asthma therapies focus on reducing symptoms but fail to restore existing structural damage. Mesenchymal stromal cell (MSC) administration can ameliorate airway inflammation and reverse airway remodeling. However, differences in patient disease microenvironments seem to influence MSC therapeutic effects. A polymorphic CATT tetranucleotide repeat at position 794 of the human macrophage migration inhibitory factor (hMIF) gene has been associated with increased susceptibility to and severity of asthma. We investigated the efficacy of human MSCs in high- vs. low-hMIF environments and the impact of MIF pre-licensing of MSCs using humanized MIF mice in a clinically relevant house dust mite (HDM) model of allergic asthma. MSCs significantly attenuated airway inflammation and airway remodeling in high-MIF-expressing CATT7 mice but not in CATT5 or wild-type littermates. Differences in efficacy were correlated with increased MSC retention in the lungs of CATT7 mice. MIF licensing potentiated MSC anti-inflammatory effects at a previously ineffective dose. Mechanistically, MIF binding to CD74 expressed on MSCs leads to upregulation of cyclooxygenase 2 (COX-2) expression. Blockade of CD74 or COX-2 function in MSCs prior to administration attenuated the efficacy of MIF-licensed MSCs in vivo. These findings suggest that MSC administration may be more efficacious in severe asthma patients with high MIF genotypes (CATT6/7/8).

Serum from patients with asthma potentiates macrophage phagocytosis and human mesenchymal stromal cell therapy in experimental allergic asthma

BACKGROUND/AIMS

Although several studies have demonstrated that mesenchymal stromal cells (MSCs) exhibit beneficial immunomodulatory properties in preclinical models of allergic asthma, effects on airway remodeling have been controversial. Recent evidence has shown that MSCs modify their in vivo immunomodulatory actions depending on the specific inflammatory environment encountered. Accordingly, we assessed whether the therapeutic properties of human mesenchymal stromal cells (hMSCs) could be potentiated by conditioning these cells with serum (hMSC-serum) obtained from patients with asthma and then transplanted in an experimental model of house dust mite (HDM)-induced allergic asthma.

METHODS

hMSC and hMSC-serum were administered intratracheally 24 h after the final HDM challenge. hMSC viability and inflammatory mediator production, lung mechanics and histology, bronchoalveolar lavage fluid (BALF) cellularity and biomarker levels, mitochondrial structure and function as well as macrophage polarization and phagocytic capacity were assessed.

RESULTS

Serum preconditioning led to: (i) increased hMSC apoptosis and expression of transforming growth factor-β, interleukin (IL)-10, tumor necrosis factor-α-stimulated gene 6 protein and indoleamine 2,3-dioxygenase-1; (ii) fission and reduction of the intrinsic respiratory capacity of mitochondria; and (iii) polarization of macrophages to M2 phenotype, which may be associated with a greater percentage of hMSCs phagocytosed by macrophages. Compared with mice receiving hMSCs, administration of hMSC-serum led to further reduction of collagen fiber content, eotaxin levels, total and differential cellularity and increased IL-10 levels in BALF, improving lung mechanics. hMSC-serum promoted greater M2 macrophage polarization as well as macrophage phagocytosis, mainly of apoptotic hMSCs.

CONCLUSIONS

Serum from patients with asthma led to a greater percentage of hMSCs phagocytosed by macrophages and triggered immunomodulatory responses, resulting in further reductions in both inflammation and remodeling compared with non-preconditioned hMSCs.

Is there a role for specialized pro-resolving mediators in pulmonary fibrosis?

Pulmonary fibrotic diseases are characterized by proliferation of lung fibroblasts and myofibroblasts and excessive deposition of extracellular matrix proteins. Depending on the specific form of lung fibrosis, there can be progressive scarring of the lung, leading in some cases to respiratory failure and/or death. Recent and ongoing research has demonstrated that resolution of inflammation is an active process regulated by families of small bioactive lipid mediators termed "specialized pro-resolving mediators." While there are many reports of beneficial effects of SPMs in animal and cell culture models of acute and chronic inflammatory and immune diseases, there have been fewer reports investigating SPMs and fibrosis, especially pulmonary fibrosis. Here, we will review evidence that resolution pathways are impaired in interstitial lung disease, and that SPMs and other similar bioactive lipid mediators can inhibit fibroblast proliferation, myofibroblast differentiation, and accumulation of excess extracellular matrix in cell culture and animal models of pulmonary fibrosis, and we will consider future therapeutic implications of SPMs in fibrosis.

Functional enhancement strategies to potentiate the therapeutic properties of mesenchymal stromal cells for respiratory diseases

Respiratory diseases remain a major health concern worldwide because they subject patients to considerable financial and psychosocial burdens and result in a high rate of morbidity and mortality. Although significant progress has been made in understanding the underlying pathologic mechanisms of severe respiratory diseases, most therapies are supportive, aiming to mitigate symptoms and slow down their progressive course but cannot improve lung function or reverse tissue remodeling. Mesenchymal stromal cells (MSCs) are at the forefront of the regenerative medicine field due to their unique biomedical potential in promoting immunomodulation, anti-inflammatory, anti-apoptotic and antimicrobial activities, and tissue repair in various experimental models. However, despite several years of preclinical research on MSCs, therapeutic outcomes have fallen far short in early-stage clinical trials for respiratory diseases. This limited efficacy has been associated with several factors, such as reduced MSC homing, survival, and infusion in the late course of lung disease. Accordingly, genetic engineering and preconditioning methods have emerged as functional enhancement strategies to potentiate the therapeutic actions of MSCs and thus achieve better clinical outcomes. This narrative review describes various strategies that have been investigated in the experimental setting to functionally potentiate the therapeutic properties of MSCs for respiratory diseases. These include changes in culture conditions, exposure of MSCs to inflammatory environments, pharmacological agents or other substances, and genetic manipulation for enhanced and sustained expression of genes of interest. Future directions and challenges in efficiently translating MSC research into clinical practice are discussed.

Intense Pulsed Light Attenuates Oxidative Stress in Perennial Allergic Conjunctivitis

Objective: To assess the effects of intense pulsed light (IPL) on oxidative stress (OS) in perennial allergic conjunctivitis (PAC). Background: IPL treatment has been proven effective for dry eye disease (DED). However, we have observed that, after IPL treatment, some patients with DED combined with allergic conjunctivitis (AC), an immune response condition in which excessive OS causes and exacerbates inflammatory damage, not only show an improvement in eye dryness, but also their AC-related eye itching is relieved. The mechanism by which IPL inhibits allergic reactions is not clear. Methods: Five patients with moderate-to-severe PAC were given two IPL treatments on the periorbital skin with a 2-week interval. Visual analog scale (VAS) scores and signs of AC, including eye redness and conjunctival follicles, were assessed before the first treatment (day 1) and 2 weeks after the second treatment (day 30). Tears were also collected at the same time, and lipid oxidation (LPO) metabolite analysis was performed using liquid chromatography tandem mass spectrometry (LC-MS/MS) to investigate the effects of IPL on OS response. Results: The average VAS score significantly decreased with treatment (30.2 for day 1, 10.6 for day 30; p < 0.001). The general signs of PAC showed no difference (p > 0.05). LPO metabolite analysis revealed that 17,18-diHETE, which is an oxidation product of eicosapentaenoic acid, and 13-OXoODE, which is an oxidation product of linoleic acid, are significantly downregulated after IPL treatment. Conclusions: The photothermal effect of IPL attenuates OS in PAC, and this seems to be one of the mechanisms by which IPL treatment improves PAC. Clinical Trial Registration number: ChiCTR1900022202.

Mesenchymal Stem/Stromal Cells in Asthma Therapy: Mechanisms and Strategies for Enhancement

Asthma is a complex and heterogeneous disease characterized by chronic airway inflammation, airway hyperresponsiveness, and airway remodeling. Most asthmatic patients are well-established using standard treatment strategies and advanced biologicals. However, a small group of patients who do not respond to biological treatments or are not effectively controlled by available treatment strategies remain a clinical challenge. Therefore, new therapies are urgently needed for poorly controlled asthma. Mesenchymal stem/stromal cells (MSCs) have shown therapeutic potential in relieving airway inflammation and repairing impaired immune balance in preclinical trials owing to their immunomodulatory abilities. Noteworthy, MSCs exerted a therapeutic effect on steroid-resistant asthma with rare side effects in asthmatic models. Nevertheless, adverse factors such as limited obtained number, nutrient and oxygen deprivation in vitro, and cell senescence or apoptosis affected the survival rate and homing efficiency of MSCs, thus limiting the efficacy of MSCs in asthma. In this review, we elaborate on the roles and underlying mechanisms of MSCs in the treatment of asthma from the perspective of their source, immunogenicity, homing, differentiation, and immunomodulatory capacity and summarize strategies to improve their therapeutic effect.

Eicosapentaenoic acid is associated with the attenuation of dysfunctions of mesenchymal stem cells in the abdominal aortic aneurysm wall

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by progressive dilation of the aorta which is reportedly associated with inflammation. Previous studies suggested that eicosapentaenoic acid (EPA) has suppressive effects on AAA development via anti-inflammatory activities. However, relationships between the anti-inflammatory effects and the cells in the AAA wall are poorly understood. In this study, we visualized the distribution of EPA-containing phosphatidylcholine (EPA-PC) in the AAA wall. EPA-PC was not ubiquitously distributed in both animal (hypoperfusion-induced AAA model) and human AAA walls, suggesting the preferential incorporation of EPA into certain cells. In the EPA-PC-high region of both animal and human AAAs, mesenchymal stem cell (MSC) marker positive areas were significantly higher than those in the EPA-PC-low region. Matrix metalloproteinase-positive MSCs were significantly lower in the AAA wall of the animal model which was administered EPA-rich fish oil. These data suggest that EPA is associated with the attenuation of MSC dysfunctions, which result in the suppression of AAA development.

Eugenol-Preconditioned Mesenchymal Stem Cell-Derived Extracellular Vesicles Promote Antioxidant Capacity of Tendon Stem Cells In Vitro and In Vivo

Tendon stem cells (TSCs) are often exposed to oxidative stress at tendon injury sites, which impairs their physiological effect as well as therapeutic application. Recently, extracellular vesicles (EVs) derived from bone marrow mesenchymal stem cells (BMSCs) were shown to mediate cell protection and survival under stress conditions. The function of BMSC-EVs may be affected by pretreatment with various factors such as eugenol (EUG)—a powerful antioxidant. In our previous study, we found that H₂O₂ significantly impaired TSC proliferation and tenogenic differentiation capabilities. Apoptosis and intracellular ROS accumulation in TSCs were induced by H₂O₂. However, such H₂O₂-induced damage was prevented by treatment with EUG-BMSC-EVs. Furthermore, EUG-BMSC-EVs activated the Nrf2/HO-1 pathway to counteract H₂O₂-induced damage in TSCs. In a rat patellar tendon injury model, the ROS level was significantly higher than that in the normal tendon and TSCs not pretreated showed a poor therapeutic effect. However, EUG-BMSC-EV-pretreated TSCs significantly improved tenogenesis and matrix regeneration during tendon healing. Additionally, the EUG-BMSC-EV group had a significantly improved fiber arrangement. Overall, EUG-BMSC-EVs protected TSCs against oxidative stress and enhanced their functions in tendon injury. These findings provide a basis for potential clinical use of EUG-BMSC-EVs as a new therapeutic vehicle to facilitate TSC therapies for tendon regeneration.

Mitochondria-Rich Fraction Isolated From Mesenchymal Stromal Cells Reduces Lung and Distal Organ Injury in Experimental Sepsis

OBJECTIVES

To ascertain whether systemic administration of mitochondria-rich fraction isolated from mesenchymal stromal cells would reduce lung, kidney, and liver injury in experimental sepsis.

DESIGN

Animal study.

SETTING

Laboratory investigation.

SUBJECTS

Sixty C57BL/6 male mice.

INTERVENTIONS

Sepsis was induced by cecal ligation and puncture; sham-operated animals were used as control. At 24 hours after surgery, cecal ligation and puncture and Sham animals were further randomized to receive saline or mitochondria-rich fraction isolated from mesenchymal stromal cells (3 × 106) IV. At 48 hours, survival, peritoneal bacterial load, lung, kidney, and liver injury were analyzed. Furthermore, the effects of mitochondria on oxygen consumption rate and reactive oxygen species production of lung epithelial and endothelial cells were evaluated in vitro.

MEASUREMENTS AND MAIN RESULTS

In vitro exposure of lung epithelial and endothelial cells from cecal ligation and puncture animals to mitochondria-rich fraction isolated from mesenchymal stromal cells restored oxygen consumption rate and reduced total reactive oxygen species production. Infusion of exogenous mitochondria-rich fraction from mesenchymal stromal cells (mitotherapy) reduced peritoneal bacterial load, improved lung mechanics and histology, and decreased the expression of interleukin-1β, keratinocyte chemoattractant, indoleamine 2,3-dioxygenase-2, and programmed cell death protein 1 in lung tissue, while increasing keratinocyte growth factor expression and survival rate in cecal ligation and puncture-induced sepsis. Mitotherapy also reduced kidney and liver injury, plasma creatinine levels, and messenger RNA expressions of interleukin-18 in kidney, interleukin-6, indoleamine 2,3-dioxygenase-2, and programmed cell death protein 1 in liver, while increasing nuclear factor erythroid 2-related factor-2 and superoxide dismutase-2 in kidney and interleukin-10 in liver.

CONCLUSIONS

Mitotherapy decreased lung, liver, and kidney injury and increased survival rate in cecal ligation and puncture-induced sepsis.

Long non-coding RNA NKILA alleviates airway inflammation in asthmatic mice by promoting M2 macrophage polarization and inhibiting the NF-κB pathway

Asthma remains a severe public health problem. Long non-coding RNAs (lncRNAs) are potent regulators in various diseases including asthma. This study investigated the mechanism of lncRNA NF-κB interacting lncRNA (NKILA) in asthma. The model of asthma in mice was induced by ovalbum (OVA). LncRNA NKILA expression, serum total IgE level and expressions of inflammatory cytokines (IL-4, IL-5, IL-13, and TNF-α) in OVA-induced asthmatic mice were detected. NKILA was overexpressed to evaluate the airway inflammation and airway hyperresponsiveness (AHR) in asthmatic mice. Macrophage abundance, M1/M2-polarized macrophage numbers, and expressions of macrophage polarization-related genes were detected. Levels of the NF-κB pathway-related proteins were determined. Downregulated NKILA and upregulated total IgE level and expressions of inflammatory cytokines were observed in asthmatic mice. NKILA overexpression alleviated AHR and airway inflammation in asthmatic mice. NKILA reduced macrophage abundance and promoted M2 macrophage polarization in asthmatic mice. NKILA inhibited the NF-κB pathway in asthmatic mice. We highlighted that lncRNA NKILA limited the asthmatic airway inflammation via promoting M2 macrophage polarization and inhibiting the NF-κB pathway.

Emerging Cell-Based Therapies in Chronic Lung Diseases: What About Asthma?

Asthma is a widespread disease characterized by chronic airway inflammation. It causes substantial disability, impaired quality of life, and avoidable deaths around the world. The main treatment for asthmatic patients is the administration of corticosteroids, which improves the quality of life; however, prolonged use of corticosteroids interferes with extracellular matrix elements. Therefore, cell-based therapies are emerging as a novel therapeutic contribution to tissue regeneration for lung diseases. This study aimed to summarize the advancements in cell therapy involving mesenchymal stromal cells, extracellular vesicles, and immune cells such as T-cells in asthma. Our findings provide evidence that the use of mesenchymal stem cells, their derivatives, and immune cells such as T-cells are an initial milestone to understand how emergent cell-based therapies are effective to face the challenges in the development, progression, and management of asthma, thus improving the quality of life.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles in Lung Diseases: Current Status and Perspectives

Extracellular vesicles (EVs) have emerged as a potential therapy for several diseases. These plasma membrane-derived fragments are released constitutively by virtually all cell types-including mesenchymal stromal cells (MSCs)-under stimulation or following cell-to-cell interaction, which leads to activation or inhibition of distinct signaling pathways. Based on their size, intracellular origin, and secretion pathway, EVs have been grouped into three main populations: exosomes, microvesicles (or microparticles), and apoptotic bodies. Several molecules can be found inside MSC-derived EVs, including proteins, lipids, mRNA, microRNAs, DNAs, as well as organelles that can be transferred to damaged recipient cells, thus contributing to the reparative process and promoting relevant anti-inflammatory/resolutive actions. Indeed, the paracrine/endocrine actions induced by MSC-derived EVs have demonstrated therapeutic potential to mitigate or even reverse tissue damage, thus raising interest in the regenerative medicine field, particularly for lung diseases. In this review, we summarize the main features of EVs and the current understanding of the mechanisms of action of MSC-derived EVs in several lung diseases, such as chronic obstructive pulmonary disease (COPD), pulmonary infections [including coronavirus disease 2019 (COVID-19)], asthma, acute respiratory distress syndrome (ARDS), idiopathic pulmonary fibrosis (IPF), and cystic fibrosis (CF), among others. Finally, we list a number of limitations associated with this therapeutic strategy that must be overcome in order to translate effective EV-based therapies into clinical practice.

A mouse allergic asthma model induced by shrimp tropomyosin

Allergic asthma remains an important worldwide health issue. Animal models are valuable for understanding the pathophysiological mechanisms of asthma and the development of effective therapeutics. This study aims to develop an alternative murine model induced by shrimp tropomyosin (ST) instead of ovalbumin (OVA). To investigate responses to short-term exposure to antigens, mice were sensitized with intraperitoneal injections of ST or ST plus aluminum adjuvant on days 0, 7, 14 followed by an intranasal challenge with ST for seven consecutive days. We reveal that sensitization with ST alone or ST plus aluminum induces significant levels of serum total IgE and ST-specific IgE in mice. Challenge results show that ST causes severe eosinophilic airway inflammation. Histology analysis of the lung tissues demonstrates airway inflammation and mucus hypersecretion within the bronchi in mice exposed to ST. Analysis of the cell composition in bronchoalveolar lavage fluid (BALF) shows a significant increase in eosinophil count in ST alone and ST plus aluminum groups. We also detect increased CD4+ T lymphocytes in lung tissues and production of helper T cell type 2-associated cytokines (IL-4 and IL-5) in BALF. In addition, airway hyperresponsiveness to methacholine in ST alone and ST plus aluminum groups is much higher than that in control groups. For the chronic model, mice were sensitized by ST or ST plus aluminum adjuvant for 3weeks and challenged with ST for 6weeks. We find severe structural changes in animals upon prolonged exposure to ST, including goblet cell hyperplasia, collagen deposition, and smooth muscle thickening. In conclusion, ST-induced asthma is a simple murine model for studying pathogenesis of asthma and evaluating new therapeutic drugs.

A narrative review of research advances in mesenchymal stem cell therapy for asthma

Asthma is a chronic inflammatory disease of the airways that involves multiple cells, including inflammatory cells, structural cells, and cellular components. Glucocorticoids and beta-receptor agonists are still the first choices for asthma treatment. However, the asthma symptoms may still be poorly controlled in some patients after an optimal treatment. Mesenchymal stem cells (MSCs) are characterized by the potential for multi-directional differentiation and can exert immunomodulatory and anti-inflammatory effects. Its role in treating asthma has increasingly been recognized in recent years. In this review article, we sought to summarize the recent advances in the therapeutic effects of MSCs on several types of asthma and explain the relevant mechanisms. Articles on asthma treatment with MSCs as of January 2020 were searched in PubMed, Google Scholar, and Web of Science databases. It was found that MSCs have therapeutic effects on allergic asthma, non-allergic asthma and occupational asthma; gene-modified or pretreated MSCs improves the therapeutic effects of MSCs in asthma; MSC-derived conditioned medium or extracellular vesicles possess the considerable curative effect as MSC on asthma; and MSCs exert their therapeutic effects on asthma by restoring Th1/Th2 balance, reversing Th17/Tregs imbalance, inhibiting DC maturation, and promoting the switch of M1 to M2 and repairing epithelial injury. Thus, MSCs may be a promising treatment for asthma.

Fluorous-paired derivatization approach towards highly sensitive and accurate determination of long chain unsaturated fatty acids by liquid chromatography-tandem mass spectrometry

Long chain unsaturated fatty acids (LCUFAs) are emerging as critical contributors to inflammation and its resolution. Sensitive and accurate measurement of LCUFAs in biological samples is thus of great value in disease diagnosis and prognosis. In this work, a fluorous-derivatization approach for UPLC-MS/MS quantification of LCUFAs was developed by employing a pair of fluorous reagents, namely 3-(perfluorooctyl)-propylamine (PFPA) and 2-(perfluorooctyl)-ethylamine (PFEA). With this method, the LCUFAs in biological samples were perfluoroalkylated with PFPA and specifically retained on a fluorous-phase LC column, which largely reduced matrix interferences-induced quantitation deviation. Moreover, PFEA-labeled LCUFAs standards were introduced as one-to-one internal standards to farthest ensure unbiased results. Application of the proposed method enabled a reliable determination of eight typical LCUFAs with high sensitivity (LLOQ ranged from 30 amol to 6.25 fmol) and low matrix interferences (almost less than 10%). Such a high sensitivity could facilitate the determination of small-volume and low-concentration bio-samples. Further metabolic characterization of these targeted LCUFAs was monitored in OVA-induce asthma mice, requiring only 5 μL serum sample. Our results showed that asthmatic attack led to significant disturbances not only in the concentrations but also in the ratio among these LCUFAs. In view of the favorable advantages in sensitivity and accuracy, the present fluorous-paired derivatization approach will be expected to serve as a new avenue for dissecting the physiological and clinical implications of LCUFAs, thereby shedding light on the management of diseases related to their disturbances.

Human Mesenchymal Stromal Cell Secretome Promotes the Immunoregulatory Phenotype and Phagocytosis Activity in Human Macrophages

Human mesenchymal stromal/stem cells (hMSCs) show great promise in cell therapy due to their immunomodulatory properties. The overall immunomodulatory response of hMSCs resembles the resolution of inflammation, in which lipid mediators and regulatory macrophages (Mregs) play key roles. We investigated the effect of hMSC cell-cell contact and secretome on macrophages polarized and activated toward Mreg phenotype. Moreover, we studied the effect of supplemented polyunsaturated fatty acids (PUFAs): docosahexaenoic acid (DHA) and arachidonic acid, the precursors of lipid mediators, on hMSC immunomodulation. Our results show that unlike hMSC cell-cell contact, the hMSC secretome markedly increased the CD206 expression in both Mreg-polarized and Mreg-activated macrophages. Moreover, the secretome enhanced the expression of programmed death-ligand 1 on Mreg-polarized macrophages and Mer receptor tyrosine kinase on Mreg-activated macrophages. Remarkably, these changes were translated into improved Candida albicans phagocytosis activity of macrophages. Taken together, these results demonstrate that the hMSC secretome promotes the immunoregulatory and proresolving phenotype of Mregs. Intriguingly, DHA supplementation to hMSCs resulted in a more potentiated immunomodulation with increased CD163 expression and decreased gene expression of matrix metalloproteinase 2 in Mreg-polarized macrophages. These findings highlight the potential of PUFA supplementations as an easy and safe method to improve the hMSC therapeutic potential.

Autologous bone marrow-derived mononuclear cell therapy in three patients with severe asthma

BACKGROUND

Despite recent advances in understanding its pathophysiology and development of novel therapies, asthma remains a serious public health issue worldwide. Combination therapy with inhaled corticosteroids and long-acting β₂-adrenoceptor agonists results in disease control for many patients, but those who exhibit severe asthma are often unresponsive to conventional treatment, experiencing worse quality of life, frequent exacerbations, and increasing healthcare costs. Bone marrow-derived mononuclear cell (BMMC) transplantation has been shown to reduce airway inflammation and remodeling and improve lung function in experimental models of allergic asthma.

METHODS

This is a case series of three patients who presented severe asthma, unresponsive to conventional therapy and omalizumab. They received a single intravenous dose of autologous BMMCs (2 × 10⁷) and were periodically evaluated for 1 year after the procedure. Endpoint assessments included physical examination, quality of life questionnaires, imaging (computed tomography, single-photon emission computed tomography, and ventilation/perfusion scan), lung function tests, and a 6-min walk test.

RESULTS

All patients completed the follow-up protocol. No serious adverse events attributable to BMMC transplantation were observed during or after the procedure. Lung function remained stable throughout. A slight increase in ventilation of the right lung was observed on day 120 after BMMC transplantation in one patient. All three patients reported improvement in quality of life in the early post-procedure course.

CONCLUSIONS

This paper described for the first time the effects of BMMC therapy in patients with severe asthma, providing a basis for subsequent trials to assess the efficacy of this therapy.

MSC Based Therapies-New Perspectives for the Injured Lung

Chronic lung diseases pose a tremendous global burden. At least one in four people suffer from severe pulmonary sequelae over the course of a lifetime. Despite substantial improvements in therapeutic interventions, persistent alleviation of clinical symptoms cannot be offered to most patients affected to date. Despite broad discrepancies in origins and pathomechanisms, the important disease entities all have in common the pulmonary inflammatory response which is central to lung injury and structural abnormalities. Mesenchymal stem cells (MSC) attract particular attention due to their broadly acting anti-inflammatory and regenerative properties. Plenty of preclinical studies provided congruent and convincing evidence that MSC have the therapeutic potential to alleviate lung injuries across ages. These include the disease entities bronchopulmonary dysplasia, asthma and the different forms of acute lung injury and chronic pulmonary diseases in adulthood. While clinical trials are so far restricted to pioneering trials on safety and feasibility, preclinical results point out possibilities to boost the therapeutic efficacy of MSC application and to take advantage of the MSC secretome. The presented review summarizes the most recent advances and highlights joint mechanisms of MSC action across disease entities which provide the basis to timely tackle this global disease burden.

Multiple doses of adipose tissue-derived mesenchymal stromal cells induce immunosuppression in experimental asthma

In experimental house dust mite (HDM)‐induced allergic asthma, therapeutic administration of a single dose of adipose tissue‐derived mesenchymal stromal cells (MSCs) ameliorates lung inflammation but is unable to reverse remodeling. We hypothesized that multiple doses of MSCs might exert better therapeutic effects by reducing lung inflammation and remodeling but might also result in immunosuppressive effects in experimental asthma. HDM was administered intranasally in C57BL/6 mice. After the last HDM challenge, mice received two or three doses of MSCs (10⁵ cells per day) or saline intravenously. An additional cohort of mice received dexamethasone as a positive control for immunosuppression. Two and three doses of MSCs reduced lung inflammation, levels of interleukin (IL)‐4, IL‐13, and eotaxin; total leukocyte, CD4⁺ T‐cell, and eosinophil counts in bronchoalveolar lavage fluid; and total leukocyte counts in bone marrow, spleen, and mediastinal lymph nodes. Two and three doses of MSCs also reduced collagen fiber content and transforming growth factor‐β levels in lung tissue; however, the three‐dose regimen was more effective, and reduced these parameters to control levels, while also decreasing α‐actin content in lung tissue. Two and three doses of MSCs improved lung mechanics. Dexamethasone, two and three doses of MSCs similarly increased galectin levels, but only the three‐dose regimen increased CD39 levels in the thymus. Dexamethasone and the three‐dose, but not the two‐dose regimen, also increased levels of programmed death receptor‐1 and IL‐10, while reducing CD4⁺CD8^low cell percentage in the thymus. In conclusion, multiple doses of MSCs reduced lung inflammation and remodeling while causing immunosuppression in HDM‐induced allergic asthma.

The potential of mesenchymal stem cell therapy for chronic lung disease

Introduction: Mesenchymal stem/stromal cells (MSCs) have been shown to improve lung function and survival in chronic inflammatory lung diseases, including asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), pulmonary arterial hypertension (PAH), and silicosis.Areas covered: This review covers rationale for the use of MSC therapy, along with preclinical studies and clinical trials with MSC therapy in chronic lung diseases.Expert opinion: MSC therapy holds promise for the treatment of chronic lung diseases, mainly when administered at early stages. In clinical trials, MSC administration was safe, but associated with limited effects on clinical outcomes. Further studies are required to elucidate unresolved issues, including optimal MSC source and dose, route of administration, and frequency (single vs. multiple-dose regimens). A better understanding of the mechanisms of MSC action, local microenvironment of each disease, and development of strategies to potentiate the beneficial effects of MSCs may improve outcomes.

Eicosapentaenoic acid potentiates the therapeutic effects of adipose tissue-derived mesenchymal stromal cells on lung and distal organ injury in experimental sepsis

Background

Even though mesenchymal stromal cells (MSCs) mitigate lung and distal organ damage in experimental polymicrobial sepsis, mortality remains high. We investigated whether preconditioning with eicosapentaenoic acid (EPA) would potentiate MSC actions in experimental sepsis by further decreasing lung and distal organ injury, thereby improving survival.

Methods

In C57BL/6 mice, sepsis was induced by cecal hligation and puncture (CLP); sham-operated animals were used as control. Twenty-four hours after surgery, CLP mice were further randomized to receive saline, adipose tissue-derived (AD)-MSCs (10⁵, nonpreconditioned), or AD-MSCs preconditioned with EPA for 6 h (10⁵, EPA-preconditioned MSCs) intravenously. After 24 h, survival rate, sepsis severity score, lung mechanics and histology, protein level of selected biomarkers in lung tissue, cellularity in blood, distal organ damage, and MSC distribution (by technetium-99m tagging) were analyzed. Additionally, the effects of EPA on the secretion of resolvin-D₁ (RvD₁), prostaglandin E₂ (PGE₂), interleukin (IL)-10, and transforming growth factor (TGF)-β1 by MSCs were evaluated in vitro.

Results

Nonpreconditioned and EPA-preconditioned AD-MSCs exhibited similar viability and differentiation capacity, accumulated mainly in the lungs and kidneys following systemic administration. Compared to nonpreconditioned AD-MSCs, EPA-preconditioned AD-MSCs further reduced static lung elastance, alveolar collapse, interstitial edema, alveolar septal inflammation, collagen fiber content, neutrophil cell count as well as protein levels of interleukin-1β and keratinocyte chemoattractant in lung tissue, and morphological abnormalities in the heart (cardiac myocyte architecture), liver (hepatocyte disarrangement and Kupffer cell hyperplasia), kidney (acute tubular necrosis), spleen (increased number of megakaryocytes and lymphocytes), and small bowel (villi architecture disorganization). EPA preconditioning of MSCs resulted in increased secretion of pro-resolution and anti-inflammatory mediators (RvD₁, PGE₂, IL-10, and TGF-β).

Conclusions

Compared to nonpreconditioned cells, EPA-preconditioned AD-MSCs yielded further reductions in the lung and distal organ injury, resulting in greater improvement in sepsis severity score and higher survival rate in CLP-induced experimental sepsis. This may be a promising therapeutic approach to improve outcome in septic patients.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1365-z) contains supplementary material, which is available to authorized users.

Mesenchymal Stromal Cells Are More Effective Than Their Extracellular Vesicles at Reducing Lung Injury Regardless of Acute Respiratory Distress Syndrome Etiology

Although mesenchymal stromal cells (MSCs) have demonstrated beneficial effects on experimental acute respiratory distress syndrome (ARDS), preconditioning may be required to potentiate their therapeutic effects. Additionally, administration of cell-free products, such as extracellular vesicles (EVs) obtained from MSC-conditioned media, might be as effective as MSCs. In this study, we comparatively evaluated the effects of MSCs, preconditioned or not with serum collected from mice with pulmonary or extrapulmonary ARDS (ARDSp and ARDSexp, respectively), and the EVs derived from these cells on lung inflammation and remodeling in ARDSp and ARDSexp mice. Administration of MSCs (preconditioned or not), but not their EVs, reduced static lung elastance, interstitial edema, and collagen fiber content in both ARDSp and ARDSexp. Although MSCs and EVs reduced alveolar collapse and neutrophil cell counts in lung tissue, therapeutic responses were superior in mice receiving MSCs, regardless of preconditioning. Despite higher total cell, macrophage, and neutrophil counts in bronchoalveolar lavage fluid in ARDSp than ARDSexp, MSCs and EVs (preconditioned or not) led to a similar decrease. In ARDSp, both MSCs and EVs, regardless of preconditioning, reduced levels of tumor necrosis factor- (TNF-) α, interleukin-6, keratinocyte chemoattractant (KC), vascular endothelial growth factor (VEGF), and transforming growth factor- (TGF-) β in lung homogenates. In ARDSexp, TNF-α, interleukin-6, and KC levels were reduced by MSCs and EVs, preconditioned or not; only MSCs reduced VEGF levels, while TGF-β levels were similarly increased in ARDSexp treated either with saline, MSCs, or EVs, regardless of preconditioning. In conclusion, MSCs yielded greater overall improvement in ARDS in comparison to EVs derived from the same number of cells and regardless of the preconditioning status. However, the effects of MSCs and EVs differed according to ARDS etiology.

Integrative analysis of the contribution of mRNAs and long non‑coding RNAs to the pathogenesis of asthma

Asthma, a common but poorly controlled disease, is one of the most serious health problems worldwide; however, the mechanisms underlying the development of asthma remain unknown. Long non-coding RNAs (lncRNAs) and mRNAs serve important roles in the initiation and progression of various diseases. The present study aimed to investigate the role of differentially expressed lncRNAs and mRNAs associated with asthma. Differentially expressed lncRNAs and mRNAs were screened between the expression data of 62 patients with asthma and 43 healthy controls. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to investigate the biological functions and pathways associated with the lncRNAs and mRNAs identified. Protein-protein interaction (PPI) networks were subsequently generated. In addition, lncRNA-mRNA weighted co-expression networks were obtained. In total, 159 differentially expressed lncRNAs and 1,261 mRNAs were identified. GO and KEGG analyses revealed that differentially expressed mRNAs regulated asthma by participating in the ‘vascular endothelial (VEGF) signaling pathway’, ‘oxidative phosphorylation’, ‘Fc ε RI signaling pathway’, ‘amino sugar and nucleotide sugar metabolism’, ‘histidine metabolism’, ‘β-alanine metabolism’ and ‘extracellular matrix-receptor interaction’ (P<0.05). Furthermore, protein kinase B 1 had the highest connectivity degree in the PPI network, and was significantly enriched in the ‘VEGF signaling pathway’ and ‘Fc ε RI signaling pathway’. A total of 8 lncRNAs in the lncRNA-mRNA co-expression network were reported to interact with 52 differentially expressed genes, which were enriched in asthma-associated GO and KEGG pathways. The results obtained in the present study may provide insight into the profile of differentially expressed lncRNAs associated with asthma. The identification of a cluster of dysregulated lncRNAs and mRNAs may serve as a potential therapeutic strategy to reverse the progression of asthma.

Current understanding of the immunosuppressive properties of mesenchymal stromal cells

Several studies have demonstrated the anti-inflammatory potential of mesenchymal stromal cells (MSCs) isolated from bone marrow, adipose tissue, placenta, and other sources. Nevertheless, MSCs may also induce immunosuppression when administered systemically or directly to injured environments, as shown in different preclinical disease models. MSCs express certain receptors, including toll-like receptors and the aryl-hydrocarbon receptor, that are activated by the surrounding environment, thus leading to modulation of their immunosuppressive activity. Once MSCs are activated, they can affect a wide range of immune cells (e.g., neutrophils, monocytes/macrophages, dendritic cells, natural killer cells, T and B lymphocytes), a phenomenon that has been correlated to secretion of several mediators (e.g., indolamine 2,3-dioxygenase, galectins, prostaglandin E₂, nitric oxide, and damage- and pathogen-associated molecular patterns) and stimulation of certain signaling pathways (e.g., protein kinase R, signal transducer and activator of transcription-1, nuclear factor-κB). Additionally, MSC manipulation and culture conditions, as well as the number of passages, duration of cryopreservation, and O₂ content available, can significantly affect the immunosuppressive properties of MSCs. This review sheds light on current knowledge regarding the mechanisms by which MSCs exert immunosuppressive effects both in vitro and in vivo, focusing on the receptors expressed by MSCs, the correlation between soluble factors secreted by MSCs and their immunosuppressive effects, and interactions between MSCs and immune cells.

Quenching the fires: Pro-resolving mediators, air pollution, and smoking

Exposure to air pollution and other environmental inhalation hazards, such as occupational exposures to dusts and fumes, aeroallergens, and tobacco smoke, is a significant cause of chronic lung inflammation leading to respiratory disease. It is now recognized that resolution of inflammation is an active process controlled by a novel family of small lipid mediators termed "specialized pro-resolving mediators" or SPMs, derived mainly from dietary omega-3 polyunsaturated fatty acids. Chronic inflammation results from an imbalance between pro-inflammatory and pro-resolution pathways. Research is ongoing to develop SPMs, and the pro-resolution pathway more generally, as a novel therapeutic approach to diseases characterized by chronic inflammation. Here, we will review evidence that the resolution pathway is dysregulated in chronic lung inflammatory diseases, and that SPMs and related molecules have exciting therapeutic potential to reverse or prevent chronic lung inflammation, with a focus on lung inflammation due to inhalation of environmental hazards including urban particulate matter, organic dusts and tobacco smoke.

Serum from Asthmatic Mice Potentiates the Therapeutic Effects of Mesenchymal Stromal Cells in Experimental Allergic Asthma

Asthma is a chronic inflammatory disease characterized by airway inflammation and remodeling, which can lead to progressive decline of lung function. Although mesenchymal stromal cells (MSCs) have shown beneficial immunomodulatory properties in preclinical models of allergic asthma, effects on airway remodeling have been limited. Mounting evidence suggests that prior exposure of MSCs to specific inflammatory stimuli or environments can enhance their immunomodulatory properties. Therefore, we investigated whether stimulating MSCs with bronchoalveolar lavage fluid (BALF) or serum from asthmatic mice could potentiate their therapeutic properties in experimental asthma. In a house dust mite (HDM) extract asthma model in mice, unstimulated, asthmatic BALF‐stimulated, or asthmatic serum‐stimulated MSCs were administered intratracheally 24 hours after the final HDM challenge. Lung mechanics and histology; BALF protein, cellularity, and biomarker levels; and lymph‐node and bone marrow cellularity were assessed. Compared with unstimulated or BALF‐stimulated MSCs, serum‐stimulated MSCs further reduced BALF levels of interleukin (IL)‐4, IL‐13, and eotaxin, total and differential cellularity in BALF, bone marrow and lymph nodes, and collagen fiber content, while increasing BALF IL‐10 levels and improving lung function. Serum stimulation led to higher MSC apoptosis, expression of various mediators (transforming growth factor‐β, interferon‐γ, IL‐10, tumor necrosis factor‐α‐stimulated gene 6 protein, indoleamine 2,3‐dioxygenase‐1, and IL‐1 receptor antagonist), and polarization of macrophages to M2 phenotype. In conclusion, asthmatic serum may be a novel strategy to potentiate therapeutic effects of MSCs in experimental asthma, leading to further reductions in both inflammation and remodeling than can be achieved with unstimulated MSCs. stem cells translational medicine2019;8:301&312

Impact of one versus two doses of mesenchymal stromal cells on lung and cardiovascular repair in experimental emphysema

Background

A single administration of mesenchymal stromal cells (MSCs) has been shown to reduce lung inflammation in experimental elastase-induced emphysema; however, effects were limited in terms of lung-tissue repair and cardiac function improvement. We hypothesized that two doses of MSCs could induce further lung and cardiovascular repair by mitigating inflammation and remodeling in a model of emphysema induced by multiple elastase instillations. We aimed to comparatively investigate the effects of one versus two doses of MSCs, administered 1 week apart, in a murine model of elastase-induced emphysema.

Methods

C57BL/6 mice were randomly divided into control (CTRL) and emphysema (E) groups. Mice in the E group received porcine pancreatic elastase (0.2 IU, 50 μL) intratracheally once weekly for four consecutive weeks; the CTRL animals received sterile saline (50 μL) using the same protocol. Three hours after the last instillation, the E group was further randomized to receive either saline (SAL) or murine MSCs (10⁵ cells) intratracheally, in one or two doses (1 week apart). Fourteen days later, mice were euthanized, and all data analyzed.

Results

Both one and two doses of MSCs improved lung mechanics, reducing keratinocyte-derived chemokine and transforming growth factor-β levels in lung homogenates, total cell and macrophage counts in bronchoalveolar lavage fluid (BALF), and collagen fiber content in airways and blood vessels, as well as increasing vascular endothelial growth factor in lung homogenates and elastic fiber content in lung parenchyma. However, only the two-dose group exhibited reductions in tumor necrosis factor-α in lung tissue, BALF neutrophil and lymphocyte count, thymus weight, and total cellularity, as well as CD8⁺ cell counts and cervical lymph node CD4⁺ and CD8⁺ T cell counts, as well as further increased elastic fiber content in the lung parenchyma and reduced severity of pulmonary arterial hypertension.

Conclusions

Two doses of MSCs enhanced lung repair and improvement in cardiac function, while inducing T cell immunosuppression, mainly of CD8⁺ cells, in elastase-induced emphysema.

The Potential of Intrinsically Magnetic Mesenchymal Stem Cells for Tissue Engineering

The magnetization of mesenchymal stem cells (MSC) has the potential to aid tissue engineering approaches by allowing tracking, targeting, and local retention of cells at the site of tissue damage. Commonly used methods for magnetizing cells include optimizing uptake and retention of superparamagnetic iron oxide nanoparticles (SPIONs). These appear to have minimal detrimental effects on the use of MSC function as assessed by in vitro assays. The cellular content of magnetic nanoparticles (MNPs) will, however, decrease with cell proliferation and the longer-term effects on MSC function are not entirely clear. An alternative approach to magnetizing MSCs involves genetic modification by transfection with one or more genes derived from Magnetospirillum magneticum AMB-1, a magnetotactic bacterium that synthesizes single-magnetic domain crystals which are incorporated into magnetosomes. MSCs with either or mms6 and mmsF genes are followed by bio-assimilated synthesis of intracytoplasmic magnetic nanoparticles which can be imaged by magnetic resonance (MR) and which have no deleterious effects on MSC proliferation, migration, or differentiation. The stable transfection of magnetosome-associated genes in MSCs promotes assimilation of magnetic nanoparticle synthesis into mammalian cells with the potential to allow MR-based cell tracking and, through external or internal magnetic targeting approaches, enhanced site-specific retention of cells for tissue engineering.