Immunomodulation by mesenchymal stem cells in treating human autoimmune disease-associated lung fibrosis

CD4+LAG3+T cells are decreased in SSc-ILD and affect fibroblast mesenchymal transition by TGF-β3

Pulmonary fibrosis frequently occurs in rheumatic conditions, particularly systemic sclerosis-associated interstitial lung disease (SSc-ILD). The pathology involves cell transformation into interstitial structures and collagen accumulation. CD4+LAG3+T cells, known for immune inhibition, are relevant in autoimmunity. This study investigates CD4+LAG3+T cells in SSc-ILD. Clinical analysis revealed a correlation between CD4+LAG3+T cells and interleukin-6 (IL-6) and erythrocyte sedimentation rate (ESR). Using primary human lung fibroblasts (pHLFs) and murine bone marrow-derived macrophages (BMDMs), we showed that CD4+LAG3+T cells secreted TGF-β3 inhibits TGF-β1-induced mesenchymal transformation, modulates cellular function, and reduces collagen release. In mouse models, CD4+LAG3+T cells exhibited potential in alleviating bleomycin-induced pulmonary fibrosis. This study emphasizes CD4+LAG3+T cells' therapeutic promise against fibrosis and proposes their role as biomarkers.

Promising Therapeutic Effects of Embryonic Stem Cells-Origin Mesenchymal Stem Cells in Experimental Pulmonary Fibrosis Models: Immunomodulatory and Anti-Apoptotic Mechanisms

Interstitial lung disease (ILD) involves persistent inflammation and fibrosis, leading to respiratory failure and even death. Adult tissue-derived mesenchymal stem cells (MSCs) show potential in ILD therapeutics but obtaining an adequate quantity of cells for drug application is difficult. Daewoong Pharmaceutical's MSCs (DW-MSCs) derived from embryonic stem cells sustain a high proliferative capacity following long-term culture and expansion. The aim of this study was to investigate the therapeutic potential of DW-MSCs in experimental mouse models of ILD. DW-MSCs were expanded up to 12 passages for in vivo application in bleomycin-induced pulmonary fibrosis and collagen-induced connective tissue disease-ILD mouse models. We assessed lung inflammation and fibrosis, lung tissue immune cells, fibrosis-related gene/protein expression, apoptosis and mitochondrial function of alveolar epithelial cells, and mitochondrial transfer ability. Intravenous administration of DW-MSCs consistently improved lung fibrosis and reduced inflammatory and fibrotic markers expression in both models across various disease stages. The therapeutic effect of DW-MSCs was comparable to that following daily oral administration of nintedanib or pirfenidone. Mechanistically, DW-MSCs exhibited immunomodulatory effects by reducing the number of B cells during the early phase and increasing the ratio of Tregs to Th17 cells during the late phase of bleomycin-induced pulmonary fibrosis. Furthermore, DW-MSCs exhibited anti-apoptotic effects, increased cell viability, and improved mitochondrial respiration in alveolar epithelial cells by transferring their mitochondria to alveolar epithelial cells. Our findings indicate the strong potential of DW-MSCs in the treatment of ILD owing to their high efficacy and immunomodulatory and anti-apoptotic effects.

Potential of resveratrol in the treatment of interstitial lung disease

Interstitial lung disease (ILD) is a heterogeneous group of diseases characterized by lung injury caused by lung fibroblast proliferation, interstitial inflammation, and fibrosis. Different cell signal transduction pathways are activated in response to various proinflammatory or fibrotic cytokines, such as IL-6, and these cytokines are increased in different ILDs. The overexpressed cytokines and growth factors in ILD can activate TGF-β/Smad2/3/4, NF-κB, and JAK/STAT signal transduction pathways, promote the activation of immune cells, increase the release of pro-inflammatory and pro-fibrotic factors, differentiate fibroblasts into myofibroblasts, and promote the occurrence and development of ILD. This finding suggests the importance of signal transduction pathways in patients with ILD. Recent evidence suggests that resveratrol (RSV) attenuates excessive inflammation and pulmonary fibrosis by inhibiting the TGF-β/Smad2/3/4, NF-κB, and JAK/STAT signal transduction pathways and overactivation of immune cells. In this review, advances in lung protection and the underlying mechanisms of RSV are summarized, and the potential efficacy of RSV as a promising treatment option for ILD is highlighted.

The Restoring Effect of Human Umbilical Cord-Derived Mesenchymal Cell-Conditioned Medium (hMSC-CM) against Carbon Tetrachloride-Induced Pulmonary Fibrosis in Male Wistar Rats

Objective

Pulmonary toxicity induced by CCl₄, a model of idiopathic pulmonary fibrosis (IPF), leads to tissue remodeling and inflammation. Human umbilical cord mesenchymal cell-conditioned medium (hMSC-CM) is a potent anti-inflammatory, antioxidative, and antifibrotic agent.

Methods

Forty male Wistar rats were assigned to the control (C), olive oil control (C.O) (hMSC-CM), control (C.Ms), fibrosis (fb), and fibrosis with hMSC-CM (f.Ms) treatment groups. The groups C, C.O, and C.Ms received PBS (200 µl), olive oil (1 ml/kg), and hMSC-CM (100 μg protein/kg), respectively. The fibrosis group was administered with only CCl4 (1 ml/kg). The last group, f.Ms was treated with CCl₄ (1 ml/kg) and 100 μg protein/kg IV hMSC-CM. While the treatment with olive oil and CCl₄ was performed for 2 days/week from the first week for 12 weeks, the treatment with PBS and hMSC-CM was carried out 2 days/week from week 4^th to week 12^th. The effect of the UC-MSC culture medium treatment on the lung was evaluated by assessing lysyl oxidase (LOX), tumor necrosis factor-alpha (TNF-α), and transforming growth factor-β1 (TGF-β1) genes, and proteins expression by real-time RCR and western blotting, respectively.

Results

Lysyl oxidase (LOX), tumor necrosis factor-alpha (TNF-α), transforming growth factor-b1 (TGF-β1), malondialdehyde (MDA), and oxidative stress levels were markedly higher in the fibrosis group than in the control groups (p ≤ 0.001). Additionally, glutathione (GSH) in the fibrosis group was markedly lower than those in the control groups (p ≤ 0.001). Fibrosis in the UC-MSC treatment group had milder histopathological injuries than in the fibrosis group.

Conclusion

hMSC-MSC as a strong anti-inflammatory, antioxidative, and antifibrotic decreases the level of oxidative stress, proinflammatory cytokines, and MDA causing a restoring effect against CCl₄-induced pulmonary fibrosis.

Impairment of the NKT-STAT1-CXCL9 Axis Contributes to Vessel Fibrosis in Pulmonary Hypertension Caused by Lung Fibrosis

Rationale: Pulmonary hypertension (PH) is a common, severe comorbidity in interstitial lung diseases such as pulmonary fibrosis (PF), and it has limited treatment options. Excessive vascular fibrosis and inflammation are often present in PH, but the underlying mechanisms are still not well understood. Objectives: To identify a novel functional link between natural killer T (NKT) cell activation and vascular fibrosis in PF-PH. Methods: Multicolor flow cytometry, secretome, and immunohistological analyses were complemented by pharmacological NKT cell activation in vivo, in vitro, and ex vivo. Measurements and Main Results: In pulmonary vessels of patients with PF-PH, increased collagen deposition was linked to a local NKT cell deficiency and decreased IL-15 concentrations. In a mouse model of PH caused by lung fibrosis, pharmacological NKT cell activation using a synthetic α-galactosylceramide analog (KRN7000) restored local NKT cell numbers and ameliorated vascular remodeling and right ventricular systolic pressure. Supplementation with activated NKT cells reduced collagen deposition in isolated human pulmonary arterial smooth muscle cells (hPASMCs) and in ex vivo precision-cut lung slices of patients with end-stage PF-PH. Coculture with activated NKT cells induced STAT1 signaling in hPASMCs. Secretome analysis of peripheral blood mononuclear cells identified CXCL9 and CXCL10 as indicators of NKT cell activation. Pharmacologically, CXCL9, but not CXCL10, potently inhibited collagen deposition in hPASMCs via the chemokine receptor CXCR3. Conclusions: Our results indicate that the absence of NKT cells impairs the STAT1-CXCL9-CXCR3 axis in PF-PH and that restoration of this axis by NKT cell activation may unravel a novel therapeutic strategy to target vascular fibrosis in interstitial lung disease.

Efficacy of umbilical cord mesenchymal stromal cells for COVID-19: A systematic review and meta-analysis

Objectives

A major challenge for COVID-19 therapy is dysregulated immune response associated with the disease. Umbilical cord mesenchymal stromal cells (UC-MSCs) may be a promising candidate for COVID-19 treatment owing to their immunomodulatory and anti-inflammatory functions. Therefore, this study aimed to evaluate the effectiveness of UC-MSCs inpatients with COVID-19.

Method

Medline, Embase, PubMed, Cochrane Library, and Web of Science databases were searched to collect clinical trials concerning UC-MSCs for the treatment of COVID-19. After literature screening, quality assessment, and data extraction, a systematic review and meta-analysis of the included study were performed.

Results

This systematic review and meta-analysis were prospectively registered on PROSPERO, and the registration number is CRD42022304061. After screening, 10 studies involving 293 patients with COVID-19 were eventually included. Our meta-analysis results showed that UC-MSCs can reduce mortality (relative risk [RR] =0.60, 95% confidence interval [CI]: [0.38, 0.95], P=0.03) in COVID-19 patients. No significant correlation was observed between adverse events and UC-MSC treatment (RR=0.85, 95% CI: [0.65, 1.10], P=0.22; RR=1.00, 95%CI: [0.64, 1.58], P=1.00). In addition, treatment with UC-MSCs was found to suppress inflammation and improve pulmonary symptoms.

Conclusions

UC-MSCs hold promise as a safe and effective treatment for COVID-19.

Systematic Review Registartion

PROSPERO, identifier CRD42022304061.

Glutathione prevents high glucose-induced pancreatic fibrosis by suppressing pancreatic stellate cell activation via the ROS/TGFβ/SMAD pathway

The activation of pancreatic stellate cells (PSCs) is the key mechanism of pancreatic fibrosis, which can lead to β-cell failure. Oxidative stress is an important risk factor for PSC activation. There is no direct evidence proving if administration of glutathione can inhibit fibrosis and β-cell failure. To explore the role of glutathione in pancreatic fibrosis and β-cell failure induced by hyperglycaemia, we established a rat model of pancreatic fibrosis and β-cell failure. The model was founded through long-term oscillating glucose (LOsG) intake and the setup of a sham group and a glutathione intervention group. In vitro, rat PSCs were treated with low glucose, high glucose, or high glucose plus glutathione to explore the mechanism of high glucose-induced PSC activation and the downstream effects of glutathione. Compared with sham rats, LOsG-treated rats had higher reactive oxygen species (ROS) levels in peripheral leukocytes and pancreatic tissue while TGFβ signalling was upregulated. In addition, as the number of PSCs and pancreatic fibrosis increased, β-cell function was significantly impaired. Glutathione evidently inhibited the upregulation of TGFβ signalling and several unfavourable outcomes caused by LOsG. In vitro treatment of high glucose for 72 h resulted in higher ROS accumulation and potentiated TGFβ pathway activation in PSCs. PSCs showed myofibroblast phenotype transformation with upregulation of α-SMA expression and increased cell proliferation and migration. Treatment with either glutathione or TGFβ pathway inhibitors alleviated these changes. Together, our findings suggest that glutathione can inhibit PSC activation-induced pancreatic fibrosis via blocking ROS/TGFβ/SMAD signalling in vivo and in vitro.

Application of Wharton jelly-derived mesenchymal stem cells in patients with pulmonary fibrosis

Pulmonary fibrosis is a devastating disease that eventually leads to death and respiratory failure. Despite the wide range of drugs, including corticosteroids, endothelin antagonist, and pirfenidone, there is no effective treatment, and the only main goal of treatment is to alleviate the symptoms as much as possible to slow down the progression of the disease and improve the quality of life. Lung transplantation may be a treatment option for a few people if pulmonary fibrosis develops and there is no established treatment. Pulmonary fibrosis caused by the COVID19 virus is another problem that we face in most patients despite the efforts of the international medical communities. Therefore, achieving alternative treatment for patients is a great success. Today, basic research using stem cells on pulmonary fibrosis has published promising results. New stem cell-based therapies can be helpful in patients with pulmonary fibrosis. Wharton jelly-derived mesenchymal stem cells are easily isolated in large quantities and made available for clinical trials without causing ethical problems. These cells have higher flexibility and proliferation potential than other cells isolated from different sources and differentiated into various cells in laboratory environments. More clinical trials are needed to determine the safety and efficacy of these cells. This study will investigate the cellular and molecular mechanisms and possible effects of Wharton jelly-derived mesenchymal stem cells in pulmonary fibrosis.

Niclosamide Ethanolamine Salt Alleviates Idiopathic Pulmonary Fibrosis by Modulating the PI3K-mTORC1 Pathway

Idiopathic pulmonary fibrosis (IPF) is an interstitial pneumonia characterized by chronic progressive fibrosis, ultimately leading to respiratory failure and early mortality. Although not fully explored, the major causative factors in IPF pathogenesis are dysregulated fibroblast proliferation and excessive accumulation of extracellular matrix (ECM) deposited by myofibroblasts differentiated from pulmonary fibroblasts. More signalling pathways, including the PI3K-Akt-mTOR and autophagy pathways, are involved in IPF pathogenesis. Niclosamide ethanolamine salt (NEN) is a highly effective multitarget small-molecule inhibitor reported in antitumor studies. Here, we reported that in an IPF animal model treated with NEN for 14 days, attractive relief of pulmonary function and hydroxyproline content were observed. To further explore, the therapeutic effect of NEN in IPF and pathological changes in bleomycin-challenged mouse lung sections were assessed. Additionally, the effects of NEN on abnormal proliferation and ECM production in IPF cell models established with TGF-β1-stimulated A549 cells or DHLF-IPF cells were studied. In nonclinical studies, NEN ameliorated lung function and histopathological changes in bleomycin-challenged mice, and the lung hydroxyproline content was significantly diminished with NEN treatment. In vitro, NEN inhibited PI3K-mTORC1 signalling and arrested the cell cycle to prevent uncontrolled fibroblast proliferation. Additionally, NEN inhibited TGF-β1-induced epithelial–mesenchymal transition (EMT) and ECM accumulation via the mTORC1-4EBP1 axis. Furthermore, NEN-activated noncanonical autophagy resensitized fibroblasts to apoptosis. The above findings demonstrated the potential antifibrotic effect of NEN mediated via modulation of the PI3K-mTORC1 and autophagy pathways. These data provide strong evidence for a therapeutic role for NEN in IPF.

Stem cells from exfoliated deciduous teeth transplantation ameliorates Sjögren's syndrome by secreting soluble PD-L1

Mesenchymal stem cell transplantation (MSCT) regulates immune cells, and is a promising therapeutic approach for treating autoimmune diseases. Stem cells from human exfoliated deciduous teeth (SHED) are a unique postnatal stem cell population from the cranial neural crest with high self-renewal, multipotent differentiation, and superior immunomodulatory properties. However, the mechanisms by which SHED can treat autoimmune diseases remain unclear. Sjögren's syndrome (SS) is an autoimmune disease histologically characterized by high lymphocytic infiltration in the salivary and lacrimal glands that results in dryness symptoms. This study explores the potential of systemic transplantation of SHED to ameliorate SS-induced dryness symptoms in mice. Overall, SHED could rescue the balance of regulatory T cell (Treg)/T helper cell 17 (Th17) in the recipient SS mice. Mechanistically, SHED promoted Treg conversion and inhibited Th17 function via paracrine effects, which were related to the secretion of soluble programmed cell death ligand 1 (sPD-L1). Moreover, it directly induced Th17 apoptosis via cell-cell contact, leading to the up-regulation of Treg and down-regulation of Th17 cells. In summary, SHED-mediated rescue of Treg/Th17 balance via the sPD-L1/PD-1 pathway ameliorates the gland inflammation and dryness symptoms in SS mice. These findings suggest that SHED are a promising stem cell source for the treatment of autoimmune diseases in the clinical setting.

Ion therapy of pulmonary fibrosis by inhalation of ionic solution derived from silicate bioceramics

Pulmonary fibrosis (PF) is a chronic and progressively fatal disease, but clinically available therapeutic drugs are limited due to efficacy and side effects. The possible mechanism of pulmonary fibrosis includes the damage of alveolar epithelial cells II (AEC2), and activation of immune cells such as macrophages. The ions released from bioceramics have shown the activity in stimulating soft tissue derived cells such as fibroblasts, endothelia cells and epithelia cells, and regulating macrophage polarization. Therefore, this study proposes an "ion therapy" approach based on the active ions of bioceramic materials, and investigates the therapeutic effect of bioactive ions derived from calcium silicate (CS) bioceramics on mouse models of pulmonary fibrosis. We demonstrate that silicate ions significantly reduce pulmonary fibrosis by simultaneously regulating the functions of AEC2 and macrophages. This result suggests potential clinical applications of ion therapy for lung fibrosis.

Current therapeutic strategies for respiratory diseases using mesenchymal stem cells

Mesenchymal stromal/stem cells (MSCs) have a great potential to proliferate, undergo multi-directional differentiation, and exert immunoregulatory effects. There is already much enthusiasm for their therapeutic potentials for respiratory inflammatory diseases. Although the mechanism of MSCs-based therapy has been well explored, only a few articles have summarized the key advances in this field. We hereby provide a review over the latest progresses made on the MSCs-based therapies for four types of inflammatory respiratory diseases, including idiopathic pulmonary fibrosis, acute respiratory distress syndrome, chronic obstructive pulmonary disease, and asthma, and the uncovery of their underlying mechanisms from the perspective of biological characteristics and functions. Furthermore, we have also discussed the advantages and disadvantages of the MSCs-based therapies and prospects for their optimization.

Mesenchymal stem cells enhance Treg immunosuppressive function at the fetal-maternal interface

Well-regulated maternal-fetal immune tolerance is a prerequisite for normal pregnancy. Hyperactivated immune cells and overwhelming inflammatory responses trigger adverse gestation outcome, such as recurrent spontaneous abortion (RSA). Local exacerbation of immunomodulatory cells in maternal decidua is a critical event, tightly linked with fetus acceptance. Owning to the notable immunoregulatory potentials, mesenchymal stromal cells (MSCs) and regulatory T cells (Tregs) have been separately reported as promising therapeutic approaches for refractory RSA attributable to certain immune disorders. However, the cross-talk between MSCs and Tregs at the fetal-maternal interface remains poorly understood. Here we revealed, for the first time, that umbilical MSCs could induce expansion of decidual Foxp3⁺CD4⁺ T cells with upregulated production of IL-10 and TGF-β. Meanwhile, MSCs reinforced the immune suppressive functions of decidual Tregs (dTregs). More important, MSCs-instructed dTregs gained enhanced capacity to suppress Th1 and Th17 related inflammatory responses. In vivo data demonstrated that adoptive transfer of MSCs obviously promoted accumulation of Foxp3⁺ dTregs in lipopolysaccharide (LPS)-induced mice abortion model and spontaneous abortion model (DBA/2-mated female CBA/J mice). Furthermore, MSCs treatment effectively ameliorated absorption rate in both models. This study may offer a new insight for the application of MSCs and Tregs in clinical recurrent miscarriage.

Mesenchymal stromal/stem cells (MSCs) and MSC-derived extracellular vesicles in COVID-19-induced ARDS: Mechanisms of action, research progress, challenges, and opportunities

In late 2019, a novel coronavirus (SARS-CoV-2) emerged in Wuhan city, Hubei province, China. Rapidly escalated into a worldwide pandemic, it has caused an unprecedented and devastating situation on the global public health and society economy. The severity of recent coronavirus disease, abbreviated to COVID-19, seems to be mostly associated with the patients' immune response. In this vein, mesenchymal stromal/stem cells (MSCs) have been suggested as a worth-considering option against COVID-19 as their therapeutic properties are mainly displayed in immunomodulation and anti-inflammatory effects. Indeed, administration of MSCs can attenuate cytokine storm and enhance alveolar fluid clearance, endothelial recovery, and anti-fibrotic regeneration. Despite advantages attributed to MSCs application in lung injuries, there are still several issues __foremost probability of malignant transformation and incidence of MSCs-related coagulopathy__ which should be resolved for the successful application of MSC therapy in COVID-19. In the present study, we review the historical evidence of successful use of MSCs and MSC-derived extracellular vesicles (EVs) in the treatment of acute respiratory distress syndrome (ARDS). We also take a look at MSCs mechanisms of action in the treatment of viral infections, and then through studying both the dark and bright sides of this approach, we provide a thorough discussion if MSC therapy might be a promising therapeutic approach in COVID-19 patients.

Biomaterial-based immunoengineering to fight COVID-19 and infectious diseases

Infection by SARS-CoV-2 virus often induces the dysregulation of immune responses, tissue damage, and blood clotting. Engineered biomaterials from the nano- to the macroscale can provide targeted drug delivery, controlled drug release, local immunomodulation, enhanced immunity, and other desirable functions to coordinate appropriate immune responses and to repair tissues. Based on the understanding of COVID-19 disease progression and immune responses to SARS-CoV-2, we discuss possible immunotherapeutic strategies and highlight biomaterial approaches from the perspectives of preventive immunization, therapeutic immunomodulation, and tissue healing and regeneration. Successful development of biomaterial platforms for immunization and immunomodulation will not only benefit COVID-19 patients, but also have broad applications for a variety of infectious diseases.

Regulatory Immune Cells in Idiopathic Pulmonary Fibrosis: Friends or Foes?

The immune system is receiving increasing attention for interstitial lung diseases, as knowledge on its role in fibrosis development and response to therapies is expanding. Uncontrolled immune responses and unbalanced injury-inflammation-repair processes drive the initiation and progression of idiopathic pulmonary fibrosis. The regulatory immune system plays important roles in controlling pathogenic immune responses, regulating inflammation and modulating the transition of inflammation to fibrosis. This review aims to summarize and critically discuss the current knowledge on the potential role of regulatory immune cells, including mesenchymal stromal/stem cells, regulatory T cells, regulatory B cells, macrophages, dendritic cells and myeloid-derived suppressor cells in idiopathic pulmonary fibrosis. Furthermore, we review the emerging role of regulatory immune cells in anti-fibrotic therapy and lung transplantation. A comprehensive understanding of immune regulation could pave the way towards new therapeutic or preventive approaches in idiopathic pulmonary fibrosis.

Are activated B cells involved in the process of myocardial fibrosis after acute myocardial infarction? An in vivo experiment

BACKGROUND

Inflammatory cells infiltrate into the ischemic and hypoxic myocardial tissue after myocardial infarction. B cells gather at the site of myocardial injury and secrete cytokines to regulate immune inflammation and fiber repair processes.

METHODS

The animal experiment used ligation of the left anterior descending (LAD) artery of C57BL/6 mice to establish a mouse acute myocardial infarction (AMI) model to observe changes in activated B cells and cytokines at different time points. Twelve-week-old C57BL/6 male mice were randomly divided into the Sham group (24 mice) (thread under the LAD artery without ligation) and the AMI group (64 mice). In addition, C57BL/6 B-cell knockout (BKO) mice and C57BL/6 wild-type (WT) mice were used to establish AMI models to observe the expression levels of cardiomyocyte cytokines, such as TNF-α IL-1β, IL-6, TGF-β1, COL1-A1, COL3-AIII, TIMP, and MMP9. Moreover, pathological and collagen changes in the myocardium were analysed. One-way ANOVA and LSD method was used for comparisons of multiple and pairwise groups respectively. P < 0.05 indicated significant differences.

RESULTS

An AMI model of C57BL/6 mice was established successfully. The ratio of activated B cells and the expression of TNF-α, IL-1β, IL-6, TGF-β1, and B cell activating factor (BAFF) in the 5-day subgroup were the highest in the myocardium, spleen and peripheral blood with the most obvious myocardial inflammatory cell infiltration. The cytokines mRNA expression levels in the 5-day subgroup of the BKO group were decreased compared with those in the WT group (P < 0.05). Among the 2-week subgroups of the Sham, WT and BKO groups, the the LVEDd and LVESd of the BKO group were lower than those of the WT group (P < 0.05), and the left ventricular ejection fraction was higher than that of the WT group (P < 0.05).

CONCLUSION

Activated B cells participate in the sustained state of myocardial inflammation and immune system activation after AMI, and may affect the metabolism of myocardial collagen after AMI by secreting cytokines. Moreover, B cells promote the expression of myocardial collagen Type I and Type III and damage the left ventricular ejection function.

Regulatory Effect of PD1/PD-Ligand 1 (PD-L1) on Treg Cells in Patients with Idiopathic Pulmonary Fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a serious irreversible lung disease. The mechanism of immune checkpoint in idiopathic pulmonary fibrosis is still unknown.

Material/Methods

First, the expression levels of PD-1/PD-L1 on the surface of CD4+ T cells and the proportion of Treg cells in IPF or controls were detected by flow cytometry. Then, expression of TGF-β in blood samples was detected with ELISA. Moreover, a co-culture system was composed of fibroblasts stimulated by TGF-β and CD4+ T cells from healthy people. The proportions of Treg cells and PD-1 in the co-culture system were detected. In addition, we detected the proportion of Treg cells and the level of collagen-1 after adding PD-1 or PD-L1 protein antibody blocker to the co-culture system.

Results

Flow cytometry revealed the upregulated expression of PD-1/PD-L1 in CD4+ T cells of IPF patients. PD-1 appears to inhibit the differentiation of CD4+ T cells into Treg cells. Co-culture of myofibroblasts and CD4+ T cells induced the generation of collagen-1 and reduced the proliferation of CD4+ T cells. When PD-1 was blocked, the inhibition of Treg cell differentiation was reversed, accompanied by decreased collagen-1 production.

Conclusions

This work identified the molecular mechanism of PD-1 in patients with IPF. It may provide a new perspective on the therapeutic effect of PD-1.

Chaotic activation of developmental signalling pathways drives idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is characterised by an important remodelling of lung parenchyma. Current evidence indicates that the disease is triggered by alveolar epithelium activation following chronic lung injury, resulting in alveolar epithelial type 2 cell hyperplasia and bronchiolisation of alveoli. Signals are then delivered to fibroblasts that undergo differentiation into myofibroblasts. These changes in lung architecture require the activation of developmental pathways that are important regulators of cell transformation, growth and migration. Among others, aberrant expression of profibrotic Wnt-β-catenin, transforming growth factor-β and Sonic hedgehog pathways in IPF fibroblasts has been assessed. In the present review, we will discuss the transcriptional integration of these different pathways during IPF as compared with lung early ontogeny. We will challenge the hypothesis that aberrant transcriptional integration of these pathways might be under the control of a chaotic dynamic, meaning that a small change in baseline conditions could be sufficient to trigger fibrosis rather than repair in a chronically injured lung. Finally, we will discuss some potential opportunities for treatment, either by suppressing deleterious mechanisms or by enhancing the expression of pathways involved in lung repair. Whether developmental mechanisms are involved in repair processes induced by stem cell therapy will also be discussed.

Clinical features of COVID-19 convalescent patients with re-positive nucleic acid detection

Background

Coronavirus disease 2019 (COVID‐19) is a pandemic that has rapidly spread worldwide. Increasingly, confirmed patients being discharged according to the current diagnosis and treatment protocols, follow‐up of convalescent patients is important to knowing about the outcome.

Methods

A retrospective study was performed among 98 convalescent patients with COVID‐19 in a single medical center. The clinical features of patients during their hospitalization and 2‐week postdischarge quarantine were collected.

Results

Among the 98 COVID‐19 convalescent patients, 17 (17.3%) were detected positive severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) nucleic acid during 2‐week postdischarge quarantine. The median time from discharge to SARS‐CoV‐2 nucleic acid re‐positive was 4 days (IQR, 3‐8.5).The median time from symptoms onset to final respiratory SARS‐CoV‐2 detection of negative result was significantly longer in re‐positive group (34 days [IQR, 29.5‐42.5]) than in non‐re‐positive group (19 days [IQR, 16‐26]). On the other hand, the levels of CD3‐CD56 + NK cells during hospitalization and 2‐week postdischarge were higher in re‐positive group than in non‐re‐positive group (repeated measures ANOVA, P = .018). However, only one case in re‐positive group showed exudative lesion recurrence in pulmonary computed tomography (CT) with recurred symptoms.

Conclusion

It is still possible for convalescent patients to show positive for SARS‐CoV‐2 nucleic acid detection, but most of the re‐positive patients showed no deterioration in pulmonary CT findings. Continuous quarantine and close follow‐up for convalescent patients are necessary to prevent possible relapse and spread of the disease to some extent.

miR-301a Suppression within Fibroblasts Limits the Progression of Fibrosis through the TSC1/mTOR Pathway

Pulmonary fibrosis has been characterized by abnormal proliferation of fibroblasts and massive deposition of the extracellular matrix, which results from a complex interplay of chronic injury and inflammatory responses. MicroRNA-301a (miR-301a) is activated by multiple inflammatory stimulators, contributing to multiple tumorigenesis and autoimmune diseases. This study showed that miR-301a was overexpressed in a bleomycin-induced murine model of pulmonary fibrosis and patients with idiopathic pulmonary fibrosis (IPF). In addition, miR-301a was activated by transforming growth factor β (TGF-β) and interleukin 6 (IL-6) in normal and IPF fibroblasts, which was markedly reversed by the signal transducer and activator of transcription 3 (STAT3) inhibitor. The genetic ablation of miR-301a in mice reduced bleomycin-induced lung fibrosis, and the downregulation of miR-301a restrained proliferation and activation of fibroblasts. Furthermore, this study demonstrated that TSC1 was a functional target of miR-301a in fibroblasts, and the negative regulation of TSC1 by miR-301a promoted the severity of pulmonary fibrosis through the mammalian target of rapamycin (mTOR) signaling pathway. The blocking of miR-301a by the intravenous injection of antagomiR-301a inhibited the proliferation of fibroblasts and the structural destruction of lung tissues in the bleomycin-induced lung fibrosis mouse model. The findings revealed the crucial role of the miR-301a/TSC1/mTOR axis in the pathogenesis of pulmonary fibrosis, suggesting that miR-301a might serve as a potential therapeutic target.

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.

Risk Factors and Changes of Peripheral NK and T Cells in Pulmonary Interstitial Fibrosis of Patients with Rheumatoid Arthritis

Objective

The absolute and relative changes of peripheral NK and T subsets are unclear in rheumatoid arthritis (RA) associated with pulmonary interstitial fibrosis (RA-ILD). To investigate the clinical risk factors, especially the changes of lymphocyte subsets, in RA-ILD in order to make early diagnosis and achieve prevention of the pulmonary interstitial lesions.

Methods

A total of 100 RA and 100 RA-ILD patients were enrolled. Rheumatoid factor, anti-cyclic citrulline peptide antibody, erythrocyte sedimentation rate, immunoglobulin, and C-reactive protein were examined. The percentage and absolute number of NK, T, B, Treg, Th1, Th2, and Th17 cells in peripheral blood were determined by flow cytometry.

Results

RA-ILD is more common in older and male RA patients and/or those with higher autoantibody titers. Flow cytometry showed that the absolute and relative numbers of CD56+ NK cells were significantly higher in RA-ILD (280.40 ± 180.51 cells/μl vs. 207.66 ± 148.57 cells/μl; 16.62 ± 8.56% vs. 12.11 ± 6.47%), whereas the proportion of T cells and CD4+ T cells was lower in peripheral blood of RA-ILD patients (69.82 ± 9.30%; 39.44 ± 9.87 cells/μl) than that in RA patients (74.45 ± 8.72%; 43.29 ± 9.10 cells/μl).

Conclusions

The occurrence of RA-ILD is closely related to the older male patients with high titer of various self-antibodies. Imbalance of CD3−CD56+ NK cells and T cells with other subsets were found in RA-ILD patients, which, together with older age, male, and high levels of autoantibodies should be considered as risk factors of pulmonary interstitial lesions.

Preconditioning with interleukin-1 beta and interferon-gamma enhances the efficacy of human umbilical cord blood-derived mesenchymal stem cells-based therapy via enhancing prostaglandin E2 secretion and indoleamine 2,3-dioxygenase activity in dextran sulfate sodium-induced colitis

Preconditioning with inflammatory cytokines has improved mesenchymal stem cells characteristics, including differentiation and immunomodulating functions. In this study, we developed a preconditioning combination strategy using interleukin-1beta (IL-1β) and interferon-gamma (IFN-γ) to enhance the immuneregulatory ability of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs). Our results showed that hUCB-MSCs preconditioned with IL-1β and IFN-γ (primed hUCB-MSCs) created a statistically significant decrease in peripheral blood mononuclear cell proliferation, indicating that their immunosuppressive ability was increased. The secretion of PGE2, cyclooxygenase 2 mRNA expression, and indoleamine 2,3-dioxygenase (IDO) mRNA expression in primed hUCB-MSCs was significantly higher than those in the untreated hUCB-MSCs or the IL-1β or IFN-γ only treated hUCB-MSCs. When inhibitors of IDO and PGE2 were treated, peripheral blood mononuclear cell proliferation, which is inhibited by primed hUCB-MSCs, was recovered. We found that Th1 T cell differentiation was also inhibited by PGE2 and IDO in the primed hUCB-MSCs, and Tregs differentiation was increased by PGE2 and IDO in the primed hUCB-MSCs. Furthermore, the primed hUCB-MSCs as well as supernatants increase CD4⁺ T cells migration. We demonstrated the therapeutic effects of primed hUCB-MSCs in dextran sulfate sodium-induced colitis model. In conclusion, we have demonstrated that primed hUCB-MSCs simultaneously enhance PGE2 and IDO and greatly improve the immunoregulatory capacity of MSCs, and we have developed an optimal condition for pretreatment of MSCs for the treatment of immune diseases. Our results raise the possibility that the combination of PGE2 and IDO could be therapeutic mediators for controlling immunosuppression of MSCs.

Sclerosis as a predictive factor for failure after bulbar urethroplasty: a prospective single-centre study

OBJECTIVE

The aim of this study was to assess whether sclerosis in histology following bulbar urethroplasty is a predictive factor for failure of surgery.

MATERIALS AND METHODS

Resected stricture specimens from 45 patients undergoing open urethroplasty with excision and anastomosis were collected prospectively during 2011-2014. Histopathological characteristics, including fibrosis (grade I-III), inflammation and sclerosis, were evaluated using different routine staining. These specimens were compared to normal urethral resection specimens from patients undergoing sex-correction surgery. The uropathologist who conducted the analyses was blinded to the study design.

RESULTS

The outcomes of the histological classifications were as follows: 19 patients had grade I fibrosis, of whom three had failures; 13 patients had grade II fibrosis, without any failures; and the most severe fibrosis, grade III, including sclerosis, was found in 13 patients (11 with sclerosis), with failure in eight. Sclerosis was a significant risk factor for restricture when comparing patients with sclerosis and those without sclerosis, and likewise when adjusting for age, inflammation and stricture length.

CONCLUSION

Histological findings of sclerosis in the resected urethral stricture specimen indicate a significantly higher risk for restricture after urethroplasty surgery.

The Use of Human Mesenchymal Stem Cells as Therapeutic Agents for the in vivo Treatment of Immune-Related Diseases: A Systematic Review

Background: One of the greatest challenges for medicine is to find a safe and effective treatment for immune-related diseases. However, due to the low efficacy of the treatment available and the occurrence of serious adverse effects, many groups are currently searching for alternatives to the traditional therapy. In this regard, the use of human mesenchymal stem cells (hMSCs) represents a great promise for the treatment of a variety of immune-related diseases due to their potent immunomodulatory properties. The main objective of this study is, therefore, to present and summarize, through a systematic review of the literature, in vivo studies in which the efficacy of the administration of hMSCs for the treatment of immune-related diseases was evaluated. Methods: The article search was conducted in PubMed/MEDLINE, Scopus and Web of Science databases. Original research articles assessing the therapeutic potential of hMSCs administration for the in vivo treatment immune-related diseases, published from 1984 to December 2017, were selected and evaluated. Results: A total of 132 manuscripts formed the basis of this systematic review. Most of the studies analyzed reported positive results after hMSCs administration. Clinical effects commonly observed include an increase in the survival rates and a reduction in the severity and incidence of the immune-related diseases studied. In addition, hMSCs administration resulted in an inhibition in the proliferation and activation of CD19⁺ B cells, CD4⁺ Th1 and Th17 cells, CD8⁺ T cells, NK cells, macrophages, monocytes, and neutrophils. The clonal expansion of both Bregs and Tregs cells, however, was stimulated. Administration of hMSCs also resulted in a reduction in the levels of pro-inflammatory cytokines such as IFN-γ, TNF-α, IL-1, IL-2, IL-12, and IL-17 and in an increase in the levels of immunoregulatory cytokines such as IL-4, IL-10, and IL-13. Conclusions: The results obtained in this study open new avenues for the treatment of immune-related diseases through the administration of hMSCs and emphasize the importance of the conduction of further studies in this area.

Nab-paclitaxel interrupts cancer-stromal interaction through C-X-C motif chemokine 10-mediated interleukin-6 downregulation in vitro

Cancer‐associated fibroblasts (CAF), derived from stroma of cancer tissues, interact with cancer cells and play an important role in cancer initiation, growth, and metastasis. Nab‐paclitaxel (nab‐PTX) is a 130 nm albumin‐binding paclitaxel and recommended for many types of cancer chemotherapy. The nab‐PTX stromal‐disrupting effect during pancreatic cancer treatment has been reported. The aim of the present study was to determine the role of nab‐PTX in cancer cells and CAF interaction. Cancer cells (MIA PaCa‐2 and Panc‐1) were cocultured with CAF or treated with CAF conditioned medium, after which their migration and invasion ability, epithelial‐mesenchymal transition (EMT)‐related marker expression and C‐X‐C motif chemokine 10 (CXCL10) expression and secretion were detected. Nab‐PTX treatment was carried out during the coculture system or during preparation of CAF conditioned medium. Then cancer cell migration and invasion ability, EMT‐related marker expression, CXCL10 expression and secretion, and interleukin‐6 (IL‐6) expression and secretion by CAF were checked After coculture with CAF, migration and invasion ability of cancer cells increased. CAF also downregulated E‐cadherin and upregulated N‐cadherin and vimentin expression in cancer cells. During coculture or stimulation with cancer cell‐cultured medium, CAF significantly increased IL‐6 expression and secretion. However, nab‐PTX in the coculture system canceled CAF‐induced migration and invasion promotion and EMT‐related gene changes. Moreover, nab‐PTX increased CXCL10 expression of cancer cells which blocked CAF IL‐6 expression and secretion. Nab‐PTX treatment could increase CXCL10 expression of cancer cells which blocks CAF cancer cell migration and invasion‐promoting effect by inhibiting IL‐6 expression.

TGF-β Inhibitor SB431542 Promotes the Differentiation of Induced Pluripotent Stem Cells and Embryonic Stem Cells into Mesenchymal-Like Cells

Due to their potential for tissue engineering applications and ability to modulate the immune system and reduce inflammation, mesenchymal stem cells (MSCs) have been explored as a promising option for the treatment of chronic diseases and injuries. However, there are problems associated with the use of this type of cell that limit their applications. Several studies have been exploring the possibility to produce mesenchymal stem cells from pluripotent stem cells (PSCs). The aim of these studies is to generate MSCs with advantageous characteristics of both PSCs and MSCs. However, there are still some questions concerning the characteristics of MSCs derived from the differentiation of PSCs that must be answered before they can be used to treat diseases and injuries. The objective of this study was, therefore, to determine if PSCs exposed to SB431542, a TGF-β inhibitor, are able to differentiate to MSCs, judging by morphology, expression of mesenchymal and pluripotent stem cell markers, expression of pluripotency-related genes, and ability to differentiate to osteocytes and adipocytes. The results obtained demonstrated that it is possible to induce the differentiation of both embryonic stem cells and induce pluripotent stem cells into cells with characteristics that highly resemble those from MSCs through the inhibition of the TGF-β pathway.

Stem cells in lung repair and regeneration: Current applications and future promise

Lung diseases are major cause of morbidity and mortality worldwide. The progress in regenerative medicine and stem cell research in the lung are currently a fast-growing research topic that can provide solutions to these major health problems. Under normal conditions, the rate of cellular proliferation is relatively low in the lung in vivo, compared to other major organ systems. Lung injury leads to the activation of stem/progenitor cell populations that re-enter the cell cycle. Yet, little is known about stem cells in the lung, despite common thoughts that these cells could play a critical role in the repair of lung injuries. Nor do we fully understand the cellular and architectural complexity of the respiratory tract, and the diverse stem/progenitor cells that are involved in the lung repair and regeneration. In this review, we discuss the conceptual framework of lung stem/progenitor cell biology, and describe lung diseases, in which stem cell manipulations may be physiologically significant. In addition, we highlight the challenges of lung stem cell-based therapy.

Safety and tracking of intrathecal allogeneic mesenchymal stem cell transplantation in healthy and diseased horses

Background

It is currently unknown if the intrathecal administration of a high dose of allogeneic mesenchymal stem cells (MSCs) is safe, how MSCs migrate throughout the vertebral canal after intrathecal administration, and whether MSCs are able to home to a site of injury. The aims of the study were: 1) to evaluate the safety of intrathecal injection of 100 million allogeneic adipose-derived MSCs (ASCs); 2) to assess the distribution of ASCs after atlanto-occipital (AO) and lumbosacral (LS) injection in healthy horses; and 3) to determine if ASCs homed to the site of injury in neurologically diseased horses.

Methods

Six healthy horses received 100 × 10⁶ allogeneic ASCs via AO (n = 3) or LS injection (n = 3). For two of these horses, ASCs were radiolabeled with technetium and injected AO (n = 1) or LS (n = 1). Neurological examinations were performed daily, and blood and cerebrospinal fluid (CSF) were evaluated prior to and at 30 days after injection. Scintigraphic images were obtained immediately postinjection and at 30 mins, 1 h, 5 h, and 24 h after injection. Three horses with cervical vertebral compressive myelopathy (CVCM) received 100 × 10⁶ allogeneic ASCs labeled with green fluorescent protein (GFP) via AO injection and were euthanized 1–2 weeks after injection for a full nervous system necropsy. CSF parameters were compared using a paired student’s t test.

Results

There were no significant alterations in blood, CSF, or neurological examinations at any point after either AO or LS ASC injections into healthy horses. The radioactive signal could be identified all the way to the lumbar area after AO ASC injection. After LS injection, the signal extended caudally but only a minimal radioactive signal extended further cranially. GFP-labeled ASCs were not present at the site of disease at either 1 or 2 weeks following intrathecal administration.

Conclusions

The intrathecal injection of allogeneic ASCs was safe and easy to perform in horses. The AO administration of ASCs resulted in better distribution within the entire subarachnoid space in healthy horses. ASCs could not be found after 7 or 15 days of injection at the site of injury in horses with CVCM.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0849-6) contains supplementary material, which is available to authorized users.

TRAIL-Dependent Resolution of Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is the most common form of interstitial lung disease characterized by the persistence of activated myofibroblasts resulting in excessive deposition of extracellular matrix proteins and profound tissue remodeling. In the present study, the expression of tumor necrosis factor- (TNF-) related apoptosis-inducing ligand (TRAIL) was key to the resolution of bleomycin-induced pulmonary fibrosis. Both in vivo and in vitro studies demonstrated that Gr-1⁺TRAIL⁺ bone marrow-derived myeloid cells blocked the activation of lung myofibroblasts. Although soluble TRAIL was increased in plasma from IPF patients, the presence of TRAIL⁺ myeloid cells was markedly reduced in IPF lung biopsies, and primary lung fibroblasts from this patient group expressed little of the TRAIL receptor-2 (DR5) when compared with appropriate normal samples. IL-13 was a potent inhibitor of DR5 expression in normal fibroblasts. Together, these results identified TRAIL⁺ myeloid cells as a critical mechanism in the resolution of pulmonary fibrosis, and strategies directed at promoting its function might have therapeutic potential in IPF.

Regenerative Medicine Applications of Mesenchymal Stem Cells

A major research challenge is to develop therapeutics that assist with healing damaged tissues and organs because the human body has limited ability to restore the majority of these tissues and organs to their original state. Tissue engineering (TE) and regenerative medicine (RM) promises to offer efficient therapeutic biological strategies that use mesenchymal stem cells (MSCs). MSCs possess the capability for self-renewal, multilineage differentiation, and immunomodulatory properties that make them attractive for clinical applications. They have been extensively investigated in numerous preclinical and clinical settings in an attempt to overcome their challenges and promote tissue regeneration and repair. This review explores the exciting opportunities afforded by MSCs, their desirable properties as cellular therapeutics in RM, and implicates their potential use in clinical practice. Here, we attempt to identify challenges and issues that determine the clinical efficacy of MSCs as treatment for skeletal and non-skeletal tissues.

Mesenchymal stem cells in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a major cause of respiratory failure in critically ill patients and common outcome of various lung interstitial diseases. Its mortality remains high, and no effective pharmacotherapy, in addition to artificial ventilation and transplantation, exists. As such, the administration of mesenchymal stem or stromal cells (MSCs) is currently investigated as a new therapeutic method for pulmonary fibrosis. Clinical trials on MSC-based therapy as a potential treatment for lung injury and fibrosis are also performed. MSCs can migrate to injured sites and secrete multiple paracrine factors and then regulate endothelial and epithelial permeability, decrease inflammation, enhance tissue repair, and inhibit bacterial growth. In this review, recent studies on stem cells, particularly MSCs, involved in alleviating lung inflammation and fibrosis and their potential MSC-induced mechanisms, including migration and differentiation, soluble factor and extracellular vesicle secretion, and endogenous regulatory functions, were summarized.

Efficacy of ALK5 inhibition in myelofibrosis

Myelofibrosis (MF) is a bone marrow disorder characterized by clonal myeloproliferation, aberrant cytokine production, extramedullary hematopoiesis, and bone marrow fibrosis. Although somatic mutations in JAK2, MPL, and CALR have been identified in the pathogenesis of these diseases, inhibitors of the Jak2 pathway have not demonstrated efficacy in ameliorating MF in patients. TGF-β family members are profibrotic cytokines and we observed significant TGF-β1 isoform overexpression in a large cohort of primary MF patient samples. Significant overexpression of TGF-β1 was also observed in murine clonal MPL^W515L megakaryocytic cells. TGF-β1 stimulated the deposition of excessive collagen by mesenchymal stromal cells (MSCs) by activating the TGF-β receptor I kinase (ALK5)/Smad3 pathway. MSCs derived from MPL^W515L mice demonstrated sustained overproduction of both collagen I and collagen III, effects that were abrogated by ALK5 inhibition in vitro and in vivo. Importantly, use of galunisertib, a clinically active ALK5 inhibitor, significantly improved MF in both MPL^W515L and JAK2^V617F mouse models. These data demonstrate the role of malignant hematopoietic stem cell (HSC)/TGF-β/MSC axis in the pathogenesis of MF, and provide a preclinical rationale for ALK5 blockade as a therapeutic strategy in MF.

TGF-β1-miR-200a-PTEN induces epithelial-mesenchymal transition and fibrosis of pancreatic stellate cells

Although the function of miR-200a has been discussed in many cancers and fibrotic diseases, its role in pancreatic fibrosis is still poorly understood. In this study, we for the first time confirm that miR-200a attenuates TGF-β1-induced pancreatic stellate cells activation and extracellular matrix formation. First, we find that TGF-β1 induces activation and extracellular matrix (ECM) formation in PSCs, and the effects are blocked by the inhibitor of PI3K (LY294002). Furthermore, we identify that miR-200a is down-regulated in TGF-β1-activated PSCs, and up-regulation of miR-200a inhibits PSCs activation induced by TGF-β1. Meanwhile, TGF-β1 inhibits the expression of the epithelial marker E-cadherin, and increases the expression of mesenchymal markers vimentin, and the expression of ECM proteins a-SMA and collagen I, while miR-200a mimic reversed the above effects in PSCs, indicating that miR-200a inhibits TGF-β1-induced activation and epithelial-mesenchymal transition (EMT). In addition, overexpression of miR-200a promotes the expression of PTEN and decreases the expression of matrix proteins and attenuates phosphorylation of Akt and mTOR. Taken together, our study uncovers a novel mechanism that miR-200a attenuates TGF-β1-induced pancreatic stellate cells activation and ECM formation through inhibiting PTEN /Akt/mTOR pathway.

TSG-6 secreted by mesenchymal stem cells suppresses immune reactions influenced by BMP-2 through p38 and MEK mitogen-activated protein kinase pathway. Cell Tissue Res. 2017;368:551-561. [PMID: 28247086 DOI: 10.1007/s00441-017-2581-4]

Bone morphogenetic protein 2 (BMP-2) has a critical function in bone and cartilage development and in repairing damaged organs and tissue. However, clinical use of BMP-2 at doses of 0.5-1 mg/ml for orthopedics has been associated with severe postoperative swelling requiring emergency surgical intervention. We determined whether a high concentration of BMP-2 induces inflammatory responses in macrophages and the suppression of osteogenesis in hMSCs. We obtained human periodontal ligament stem cells and bone marrow stem cells from the maxilla, i.e., human mesenchymal stem cells (hMSCs), from the periodontal ligament of extracted third molar teeth and from the bone marrow of the maxilla, respectively. Osteogenic differentiation was measured by alkaline phosphatase activity and alizarin red S staining. Proteins were assessed by flow cytometry, enzyme-linked immunosorbent assay, Western blot and immunocytochemistry. Changes of gene expression were measured by reverse transcription plus the polymerase chain reaction (RT-PCR) and real-time PCR. A high BMP-2 concentration inhibited the early stages of osteogenesis in hMSCs. Co-culturing THP-1 cells (human monocytic cells) with hMSCs reduced the late stages of osteogenesis compared with those seen in hMSCs alone. In addition, high-dose BMP-2 induced the expression of inflammatory cytokines in THP-1 cells and the expression of the anti-inflammatory cytokine tumor-necrosis-factor-α-inducible gene 6 protein (TSG-6) in hMSCs. Consistent with the anti-inflammatory effects of hMSCs when co-cultured with THP-1 cells, interleukin-1β expression was downregulated by TSG-6 treatment of THP-1 cells. Our findings suggest that a high BMP-2 concentration triggers inflammation that causes inflammatory cytokine release from THP-1 cells, leading to the suppression of osteogenesis, whereas TSG-6 secreted by hMSCs suppresses inflammatory reactions through p38 and ERK in the mitogen-activated protein kinase pathway.