The Immunomodulatory and Therapeutic Effects of Mesenchymal Stromal Cells for Acute Lung Injury and Sepsis

MSCs alleviate LPS-induced acute lung injury by inhibiting the proinflammatory function of macrophages in mouse lung organoid-macrophage model

Acute lung injury (ALI) is an inflammatory disease associated with alveolar injury, subsequent macrophage activation, inflammatory cell infiltration, and cytokine production. Mesenchymal stem cells (MSCs) are beneficial for application in the treatment of inflammatory diseases due to their immunomodulatory effects. However, the mechanisms of regulatory effects by MSCs on macrophages in ALI need more in-depth study. Lung tissues were collected from mice for mouse lung organoid construction. Alveolar macrophages (AMs) derived from bronchoalveolar lavage and interstitial macrophages (IMs) derived from lung tissue were co-cultured, with novel matrigel-spreading lung organoids to construct an in vitro model of lung organoids-immune cells. Mouse compact bone-derived MSCs were co-cultured with organoids-macrophages to confirm their therapeutic effect on acute lung injury. Changes in transcriptome expression profile were analyzed by RNA sequencing. Well-established lung organoids expressed various lung cell type-specific markers. Lung organoids grown on spreading matrigel had the property of functional cells growing outside the lumen. Lipopolysaccharide (LPS)-induced injury promoted macrophage chemotaxis toward lung organoids and enhanced the expression of inflammation-associated genes in inflammation-injured lung organoids-macrophages compared with controls. Treatment with MSCs inhibited the injury progress and reduced the levels of inflammatory components. Furthermore, through the nuclear factor-κB pathway, MSC treatment inhibited inflammatory and phenotypic transformation of AMs and modulated the antigen-presenting function of IMs, thereby affecting the inflammatory phenotype of lung organoids. Lung organoids grown by spreading matrigel facilitate the reception of external stimuli and the construction of in vitro models containing immune cells, which is a potential novel model for disease research. MSCs exert protective effects against lung injury by regulating different functions of AMs and IMs in the lung, indicating a potential mechanism for therapeutic intervention.

Viral airway injury promotes cell engraftment in an in vitro model of cystic fibrosis cell therapy

Cell therapy is a potential treatment for cystic fibrosis (CF). However, cell engraftment into the airway epithelium is challenging. Here, we model cell engraftment in vitro using the air-liquid interface (ALI) culture system by injuring well-differentiated CF ALI cultures and delivering non-CF cells at the time of peak injury. Engraftment efficiency was quantified by measuring chimerism by droplet digital PCR and functional ion transport in Ussing chambers. Using this model, we found that human bronchial epithelial cells (HBECs) engraft more efficiently when they are cultured by conditionally reprogrammed cell (CRC) culture methods. Cell engraftment into the airway epithelium requires airway injury, but the extent of injury needed is unknown. We compared three injury models and determined that severe injury with partial epithelial denudation facilitates long-term cell engraftment and functional CFTR recovery up to 20% of wildtype function. The airway epithelium promptly regenerates in response to injury, creating competition for space and posing a barrier to effective engraftment. We examined competition dynamics by time-lapse confocal imaging and found that delivered cells accelerate airway regeneration by incorporating into the epithelium. Irradiating the repairing epithelium granted engrafting cells a competitive advantage by diminishing resident stem cell proliferation. Intentionally, causing severe injury to the lungs of people with CF would be dangerous. However, naturally occurring events like viral infection can induce similar epithelial damage with patches of denuded epithelium. We found that viral preconditioning promoted effective engraftment of cells primed for viral resistance.NEW & NOTEWORTHY Cell therapy is a potential treatment for cystic fibrosis (CF). Here, we model cell engraftment by injuring CF air-liquid interface cultures and delivering non-CF cells. Successful engraftment required severe epithelial injury. Intentionally injuring the lungs to this extent would be dangerous. However, naturally occurring events like viral infection induce similar epithelial damage. We found that viral preconditioning promoted the engraftment of cells primed for viral resistance leading to CFTR functional recovery to 20% of the wildtype.

Intravitreal allogeneic mesenchymal stem cells: a non-randomized phase II clinical trial for acute non-arteritic optic neuropathy

BACKGROUND

An effective treatment for acute non-arteritic ischemic optic neuropathy (NA-AION) has not been known or proven yet. Previous studies have suggested a neuroprotective effect of allogeneic bone marrow-derived mesenchymal stem cells. This study aims to report the results of a clinical trial on patients with acute non-arteritic optic neuropathy (NA-AION) treated with an intravitreal injection of allogeneic bone marrow-derived mesenchymal stem cells (BM-MSCs) (MSV®).

METHODS

We conducted a prospective, non-randomized, clinical phase-II study (Eudra CT number 2016-003029-40; ClinicalTrials.gov Registry NCT03173638) that included 5 patients with acute unilateral NA-AION diagnosed within 2 weeks after symptom onset and who received an intravitreal injection of allogeneic BM-MSCs (0.05 ml; cell concentration: 1.5 × 106cells/mL). The patients underwent regular ophthalmological examinations and were followed for one year.

RESULTS

In this trial, allogeneic BM-MSCs appeared to be safe as no patients developed signs of acute nor chronic intraocular inflammation or a significant change in intraocular pressure, although an epiretinal membrane was developed in one patient. A retrolental aggregate formed shortly after the injection spontaneously disappeared within a few weeks in another phakic patient, leaving a subcapsular cataract. Visual improvement was noted in 4 patients, and amplitudes of P100 on the visually evoked potentials recordings increased in three patients. The retinal nerve fiber layer and macular ganglion cell layer thicknesses significantly decreased during the follow-up.

CONCLUSIONS

Besides the development of an epiretinal membrane in one patient, the intravitreal application of allogeneic BM-MSCs appeared to be intraocularly well tolerated. Consequently, not only NA-AION but also BM-MSCs deserve more clinical investigational resources and a larger randomized multicenter trial that would provide stronger evidence both about safety and the potential therapeutic efficacy of intravitreally injected allogeneic BM-MSCs in acute NA-AION.

TRIAL REGISTRATION

Safety Assessment of Intravitreal Mesenchymal Stem Cells for Acute Non-Arteritic Anterior Ischemic Optic Neuropathy (NEUROSTEM). NCT03173638. Registered June 02, 2017 https://clinicaltrials.gov/ct2/show/NCT03173638 .

Macrophage Inactivation by Small Molecule Wedelolactone via Targeting sEH for the Treatment of LPS-Induced Acute Lung Injury

Soluble epoxide hydrolase (sEH) plays a critical role in inflammation by modulating levels of epoxyeicosatrienoic acids (EETs) and other epoxy fatty acids (EpFAs). Here, we investigate the possible role of sEH in lipopolysaccharide (LPS)-mediated macrophage activation and acute lung injury (ALI). In this study, we found that a small molecule, wedelolactone (WED), targeted sEH and led to macrophage inactivation. Through the molecular interaction with amino acids Phe362 and Gln384, WED suppressed sEH activity to enhance levels of EETs, thus attenuating inflammation and oxidative stress by regulating glycogen synthase kinase 3beta (GSK3β)-mediated nuclear factor-kappa B (NF-κB) and nuclear factor E2-related factor 2 (Nrf2) pathways in vitro. In an LPS-stimulated ALI animal model, pharmacological sEH inhibition by WED or sEH knockout (KO) alleviated pulmonary damage, such as the increase in the alveolar wall thickness and collapse. Additionally, WED or sEH genetic KO both suppressed macrophage activation and attenuated inflammation and oxidative stress in vivo. These findings provided the broader prospects for ALI treatment by targeting sEH to alleviate inflammation and oxidative stress and suggested WED as a natural lead candidate for the development of novel synthetic sEH inhibitors.

The antimicrobial peptide LK2(6)A(L) exhibits anti-inflammatory activity by binding to the myeloid differentiation 2 domain and protects against LPS-induced acute lung injury in mice

Acute lung injury (ALI) is a life-threatening disease that is generally attributable to an uncontrolled inflammatory response in the lung, but there is a lack of effective treatments. At present, regulating the inflammatory response has become an important strategy for treating ALI. In the present study, LK2(6)A(L), a peptide derived from the natural antimicrobial peptide temporin-1CEa, inhibited lipopolysaccharide (LPS)-induced expression of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and NO in RAW264.7 cells. Herein, the anti-inflammatory mechanism of LK2(6)A(L) was investigated. The RNA-sequencing (RNA-seq) results showed that LK2(6)A(L) significantly inhibited the TLR4-mediated NF-κB and MAPK signaling pathways in LPS-induced RAW264.7 cells. The results of co-immunoprecipitation (Co-IP), pull-down experiment, confocal laser scanning microscopy, and surface plasmon resonance (SPR) suggested that MD2 was the direct target of LK2(6)A(L). Chemical inhibition of MD2 and its knockdown abolished the anti-inflammatory effect of LK2(6)A(L). Molecular dynamic simulation indicated that LK2(6)A(L) could bind to the active domain of the MD2 hydrophobic pocket via six hydrogen bonds. The truncated peptides were designed based on analysis of the molecular docking of LK2(6)A(L) to MD2. The truncated peptide IS-7 showed strong affinity to MD2 and a remarkable inhibitory effect on pro-inflammatory factors that was comparable to the effect of LK2(6)A(L). Finally, LK2(6)A(L) and IS-7 relieved inflammatory symptoms and lung tissue destruction in the ALI mouse model. Overall, our study suggested that LK2(6)A(L) showed promising anti-inflammatory activity by targeting MD2, and the amino acid domain 7-13 was an important area that binds with MD2 and also an anti-inflammatory active region. LK2(6)A(L) and IS-7 may be potential new treatments for ALI and other acute inflammatory diseases.

Inula japonica ameliorated the inflammation and oxidative stress in LPS-induced acute lung injury through the MAPK/NF-κB and Keap1/Nrf2 signalling pathways

OBJECTIVES

To investigate the protective effect and underlying mechanism of Inula japonica (TEIJ) in the treatment of acute lung injury (ALI).

METHODS

Protective effects of TEIJ in the inflammation and oxidative stress were studied in lipopolysaccharide (LPS)-induced ALI mice. Meanwhile, Western blot and real-time qPCR were carried out to investigate the underlying mechanism of TEIJ for ALI as well as immunohistochemistry.

KEY FINDINGS

TEIJ significantly alleviated the course of ALI via suppressing the interstitial infiltrated inflammatory cells, the increase of inflammatory factors and the decrease of anti-oxidative factors. TEIJ inactivated the MAPK/NF-κB signalling pathway to suppress the transcription of its downstream target genes, such as TNF-α, IL-6, etc. Meanwhile, TEIJ activated the Keap1/Nrf2 signalling pathway to regulate expression levels of Nrf2 and its target proteins. The results of LC-QTOF-MS/MS indicated potential active constituents of I. japonica, terpenoids and flavonoids. Additionally, terpenoids and flavonoids synergistically alleviated LPS-induced ALI depending on MAPK/NF-κB and Keap1/Nrf2 signalling pathways.

CONCLUSION

I. japonica could be considered a potential agent to treat ALI via regulating the MAPK/NF-κB and Keap1/Nrf2 signalling pathways.

Total terpenoids of Inula japonica activated the Nrf2 receptor to alleviate the inflammation and oxidative stress in LPS-induced acute lung injury

BACKGROUND

Acute lung injury (ALI) is a life-threatening lung disease and characterized by pulmonary edema and atelectasis. Inula japonica Thunb. is a commonly used traditional Chinese medicine for the treatment of lung diseases. However, the potential effect and mechanism of total terpenoids of I. japonica (TTIJ) on ALI remain obscure.

PURPOSE

This study focused on the protective effect of TTIJ on lipopolysaccharide (LPS)-induced ALI in mice and its potential mechanism.

STUDY DESIGN AND METHODS

A mouse model of ALI was established by intratracheal instillation of LPS to investigate the protective effect of TTIJ. RNA-seq and bioinformatics were then performed to reveal the underlying mechanism. Finally, western blot and real-time qPCR were used to verify the effects of TTIJ on the inflammation and oxidative stress.

RESULTS

TTIJ notably attenuated LPS-induced histopathological changes of lung. The RNA-seq result suggested that the protective effect of TTIJ on LPS-induced ALI were associated with the Toll-like receptor 4 (TLR4) and nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling pathways. Pretreatment with TTIJ significantly reduced the inflammation and oxidative stress via regulating levels of pro-inflammatory and anti-oxidative cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), superoxide dismutase (SOD), and glutathione (GSH), in LPS-induced ALI mice. TTIJ treatment could suppress the cyclooxygenase-2 (COX-2) expression level and the phosphorylation of p65, p38, ERK, and JNK through the inactivation of the MAPK/NF-κB signaling pathway in a TLR4-independent manner. Meanwhile, TTIJ treatment upregulated expression levels of proteins involved in the Nrf2 signaling pathway, such as heme oxygenase-1 (HO-1), NAD(P)H: quinoneoxidoreductase-1 (NQO-1), glutamate-cysteine ligase catalytic subunit (GCLC), and glutamate-cysteine ligase modifier subunit (GCLM), via activating the Nrf2 receptor, which was confirmed by the luciferase assay.

CONCLUSION

TTIJ could activate the Nrf2 receptor to alleviate the inflammatory response and oxidative stress in LPS-induced ALI mice, which suggested that TTIJ could serve as the potential agent in the treatment of ALI.

Total flavonoids of Inula japonica alleviated the inflammatory response and oxidative stress in LPS-induced acute lung injury via inhibiting the sEH activity: Insights from lipid metabolomics

BACKGROUND

Acute lung injury (ALI) is a severe respiratory disease characterized by diffuse lung interstitial and respiratory distress and pulmonary edema with a mortality rate of 35%-40%. Inula japonica Thunb., known as "Xuan Fu Hua" in Chinese, is a traditional Chinese medicine Inulae Flos to use for relieving cough, eliminating expectorant, and preventing bacterial infections in the clinic, and possesses an anti-pulmonary fibrosis effect. However, the effect and action mechanism of I. japonica on ALI is still unclear.

PURPOSE

This study aimed to investigate the protective effect and underlying mechanism of total flavonoids of I. japonica (TFIJ) in the treatment of ALI.

STUDY DESIGN AND METHODS

A mouse ALI model was established through administration of LPS by the intratracheal instillation. Protective effects of TFIJ in the inflammation and oxidative stress were studied in LPS-induced ALI mice based on inflammatory and oxidative stress factors, including MDA, MPO, SOD, and TNF-α. Lipid metabolomics, bioinformatics, Western blot, quantitative real-time PCR, and immunohistochemistry were performed to reveal the potential mechanism of TFIJ in the treatment of ALI.

RESULTS

TFIJ significantly alleviated the interstitial infiltration of inflammatory cells and the collapse of the alveoli in LPS-induced ALI mice. Lipid metabolomics demonstrated that TFIJ could significantly affect the CYP2J/sEH-mediated arachidonic acid metabolism, such as 11,12-EET, 14,15-EET, 8,9-DHET, 11,12-DHET, and 14,15-DHET, revealing that sEH was the potential target of TFIJ, which was further supported by the recombinant sEH-mediated the substrate hydrolysis in vitro (IC₅₀ = 1.18 μg/ml). Inhibition of sEH by TFIJ alleviated the inflammatory response and oxidative stress via the MAPK, NF-κB, and Nrf2 signaling pathways.

CONCLUSION

These results demonstrated that TFIJ could suppress the sEH activity to stabilize the level of EETs, allowing the alleviation of the pathological course of lung injury in LPS-treated mice, which suggested that TFIJ could serve as the potential agents in the treatment of ALI.

Activated Mesenchymal Stromal Cell Therapy for Treatment of Multi-Drug Resistant Bacterial Infections in Dogs

New and creative approaches are required to treat chronic infections caused by increasingly drug-resistant strains of bacteria. One strategy is the use of cellular therapy employing mesenchymal stromal cells (MSC) to kill bacteria directly and to also activate effective host immunity to infection. We demonstrated previously that activated MSC delivered systemically could be used effectively together with antibiotic therapy to clear chronic biofilm infections in rodent models. Therefore, we sought in the current studies to gain new insights into the antimicrobial properties of activated canine MSC and to evaluate their effectiveness as a novel cellular therapy for treatment of naturally-occurring drug resistant infections in dogs. These studies revealed that canine MSC produce and secrete antimicrobial peptides that synergize with most classes of common antibiotics to trigger rapid bactericidal activity. In addition, activated canine MSC migrated more efficiently to inflammatory stimuli, and secreted factors associated with wound healing and fibroblast proliferation and recruitment of activated neutrophils. Macrophages incubated with conditioned medium from activated MSC developed significantly enhanced bactericidal activity. Clinical studies in dogs with chronic multidrug resistant infections treated by repeated i.v. delivery of activated, allogeneic MSC demonstrated significant clinical benefit, including infection clearance and healing of infected tissues. Taken together, the results of these studies provide new insights into antimicrobial activity of canine MSC, and their potential clinical utility for management of chronic, drug-resistant infections.

RGD-Hydrogel Improves the Therapeutic Effect of Bone Marrow-Derived Mesenchymal Stem Cells on Phosgene-Induced Acute Lung Injury in Rats

Mesenchymal stem cells (MSCs) have promising potential in the treatment of various diseases, such as the therapeutic effect of bone marrow-derived MSCs for phosgene-induced acute lung injury (P-ALI). However, MSC-related therapeutics are limited due to poor cell survival, requiring appropriate MSC delivery systems to maximise therapeutic capacity. Biomaterial RGD-hydrogel is a potential cell delivery vehicle as it can mimic the natural extracellular matrix and provide cell adhesion support. The application of RGD-hydrogel in the MSC treatment of respiratory diseases is scarce. This study reports that RGD-hydrogel has good biocompatibility and can increase the secretion of Angiopoietin-1, hepatocyte growth factor, epidermal growth factor, vascular endothelial cell growth factor, and interleukin-10 in vitro MSCs. The hydrogel-encapsulated MSCs could further alleviate P-ALI and show better cell survival in vivo. Overall, RGD-hydrogel could improve the MSC treatment of P-ALI by modulating cell survival and reparative activities. It is exciting to see more and more ways to unlock the therapeutic potential of MSCs.

Effect of Bone Marrow Mesenchymal Stromal Cell Therapies in Rodent Models of Sepsis: A Meta-Analysis

Background

Multiple preclinical studies have demonstrated that bone‐marrow derived mesenchymal stromal (stem) cells [MSC(M)] positively influence the severity of sepsis symptoms and mortality in rodent models. However, this remains an inconclusive finding.

Objective

To review the effect of naïve MSC(M) in rodent models of sepsis.

Methods

The PubMed, EMBASE, and Web of Science databases were searched up to August 31, 2021. Inclusion criteria according to PICOS criteria were as follows: (1) population: rodents; (2) intervention: unmodified MSC(M); (3) comparison: not specified; (4) primary outcome: the effects of MSC(M) cell therapy on the mortality of rodent models of sepsis and endotoxemia; (5) study: experimental studies. Multiple prespecified subgroup and meta-regression analysis were conducted. Following quality assessment, random effects models were used for this meta-analysis.The inverse variance method of the fixed effects model was used to calculate the pooled odds ratios (ORs) and their 95% confidence intervals (CIs).

Results

twenty-four animal studies met the inclusion criteria. Our results revealed an overall OR difference between animals treated with naïve MSC(M) and controls for mortality rate was 0.34(95% confidence interval: 0.27-0.44; P < 0.0001). Significant heterogeneity among studies was observed.

Conclusions

The findings of this meta-analysis suggest that naïve MSC(M) therapy decreased mortality in rodent models of sepsis. Additionally, we identified several key knowledge gaps, including the lack of large animal studies and uncertainty regarding the optimal dose of MSC(M) transplantation in sepsis. Before MSC(M) treatment can advance to clinical trials, these knowledge gaps must be addressed.

Mesenchymal stromal cell-derived syndecan-2 regulates the immune response during sepsis to foster bacterial clearance and resolution of inflammation

Sepsis is a life-threatening process related to a dysregulated host response to an underlying infection, which results in organ dysfunction and poor outcomes. Therapeutic strategies using mesenchymal stromal cells (MSCs) are under investigation for sepsis, with efforts to improve cellular utility. Syndecan (SDC) proteins are transmembrane proteoglycans involved with cellular signaling events including tissue repair and modulating inflammation. Bone marrow-derived human MSCs express syndecan-2 (SDC2) at a level higher than other SDC family members; thus, we explored SDC2 in MSC function. Administration of human MSCs silenced for SDC2 in experimental sepsis resulted in decreased bacterial clearance, and increased tissue injury and mortality compared with wild-type MSCs. These findings were associated with a loss of resolution of inflammation in the peritoneal cavity, and higher levels of proinflammatory mediators in organs. MSCs silenced for SDC2 had a decreased ability to promote phagocytosis of apoptotic neutrophils by macrophages in the peritoneum, and also a diminished capability to convert macrophages from a proinflammatory to a proresolution phenotype via cellular or paracrine actions. Extracellular vesicles are a paracrine effector of MSCs that may contribute to resolution of inflammation, and their production was dramatically reduced in SDC2-silenced human MSCs. Collectively, these data demonstrate the importance of SDC2 for cellular and paracrine function of human MSCs during sepsis.

Long non-coding RNA OIP5-AS1 aggravates acute lung injury by promoting inflammation and cell apoptosis via regulating the miR-26a-5p/TLR4 axis

Background

Acute lung injury (ALI) is a pulmonary disorder that leads to acute respiration failure and thereby results in a high mortality worldwide. Increasing studies have indicated that toll-like receptor 4 (TLR4) is a promoter in ALI, and we aimed to explore the underlying upstream mechanism of TLR4 in ALI.

Methods

We used lipopolysaccharide (LPS) to induce an acute inflammatory response in vitro model and a murine mouse model. A wide range of experiments including reverse transcription quantitative polymerase chain reaction, western blot, enzyme linked immunosorbent assay, flow cytometry, hematoxylin–eosin staining, RNA immunoprecipitation, luciferase activity and caspase-3 activity detection assays were conducted to figure out the expression status, specific role and potential upstream mechanism of TLR4 in ALI.

Result

TLR4 expression was upregulated in ALI mice and LPS-treated primary bronchial/tracheal epithelial cells. Moreover, miR-26a-5p was confirmed to target TLR4 according to results of luciferase reporter assay. In addition, miR-26a-5p overexpression decreased the contents of proinflammatory factors and inhibited cell apoptosis, while upregulation of TLR4 reversed these effects of miR-26a-5p mimics, implying that miR-26a-5p alleviated ALI by regulating TLR4. Afterwards, OPA interacting protein 5 antisense RNA 1 (OIP5-AS1) was identified to bind with miR-26a-5p. Functionally, OIP5-AS1 upregulation promoted the inflammation and miR-26a-5p overexpression counteracted the influence of OIP5-AS1 upregulation on cell inflammatory response and apoptosis.

Conclusion

OIP5-AS1 promotes ALI by regulating the miR-26a-5p/TLR4 axis in ALI mice and LPS-treated cells, which indicates a promising insight into diagnostics and therapeutics in ALI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01589-1.

Association of uteroglobin-related protein 1 with smoke inhalation injury severity

Objective

To evaluate serum uteroglobin-related protein 1 expression early after smoke inhalation injuries and its association with the severity of inhalation injury in burned patients.

Methods

Smoke or chemical inhalation injury is associated with morbidity and mortality. The consequences of inhalation result from an inflammatory response. Uteroglobin-related protein 1 is an anti-inflammatory protein and may improve lung inflammation. We hypothesized that uteroglobin-related protein 1 levels could reflect disease severity and predict outcome in patients with inhalation injury. Sixteen patients diagnosed with acute respiratory distress syndrome secondary to smoke inhalation injury were prospectively included in the study. Plasma was collected upon intensive care unit admission and within 24 hours of the inhalation injury. Bronchoscopies were carried out in all patients to assess the severity of inhalation injury within 72 hours. Uteroglobin-related protein 1 plasma levels were determined in duplicate with enzyme-linked immunosorbent assay.

Results

The mean age was 23 ± 5 years, and the inhalation injury distribution was as follows: three of grade 1, four of grade 2, and nine of grade 3. The level of uteroglobin-related protein 1 was related to inhalation severity (grade 1: 0.389 ± 0.053 arbitrary units versus grade 2: 0.474 ± 0.0423 arbitrary units versus grade 3: 0.580 ± 0.094 arbitrary units; p = 0.007).

Conclusion

Plasma levels of uteroglobin-related protein 1 are associated with the degree of lung inhalation injury.

Allogenic Use of Human Placenta-Derived Stromal Cells as a Highly Active Subtype of Mesenchymal Stromal Cells for Cell-Based Therapies

The application of mesenchymal stromal cells (MSCs) from different sources, including bone marrow (BM, bmMSCs), adipose tissue (atMSCs), and human term placenta (hPSCs) has been proposed for various clinical purposes. Accumulated evidence suggests that the activity of the different MSCs is indirect and associated with paracrine release of pro-regenerative and anti-inflammatory factors. A major limitation of bmMSCs-based treatment for autologous application is the limited yield of cells harvested from BM and the invasiveness of the procedure. Similar effects of autologous and allogeneic MSCs isolated from various other tissues were reported. The easily available fresh human placenta seems to represent a preferred source for harvesting abundant numbers of human hPSCs for allogenic use. Cells derived from the neonate tissues of the placenta (f-hPSC) can undergo extended expansion with a low risk of senescence. The low expression of HLA class I and II on f-hPSCs reduces the risk of rejection in allogeneic or xenogeneic applications in normal immunocompetent hosts. The main advantage of hPSCs-based therapies seems to lie in the secretion of a wide range of pro-regenerative and anti-inflammatory factors. This renders hPSCs as a very competent cell for therapy in humans or animal models. This review summarizes the therapeutic potential of allogeneic applications of f-hPSCs, with reference to their indirect pro-regenerative and anti-inflammatory effects and discusses clinical feasibility studies.

Bone Marrow Mesenchymal Stromal Cells on Silk Fibroin Scaffolds to Attenuate Polymicrobial Sepsis Induced by Cecal Ligation and Puncture

Suitable scaffolds with appropriate mechanical and biological properties can improve mesenchymal stromal cell (MSC) therapy. Because silk fibroins (SFs) are biocompatible materials, they were electrospun and applied as scaffolds for MSC therapy. Consequently, interferon (IFN)-primed human bone marrow MSCs on SF nanofibers were administered into a polymicrobial sepsis murine model. The IL-6 level gradually decreased from 40 ng/mL at 6 h after sepsis to 35 ng/mL at 24 h after sepsis. The IL-6 level was significantly low as 5 ng/mL in primed MSCs on SF nanofibers, and 15 ng/mL in primed MSCs on the control surface. In contrast to the acute response, inflammation-related factors, including HO-1 and COX-2 in chronic liver tissue, were effectively inhibited by MSCs on both SF nanofibers and the control surface at the 5-day mark after sepsis. An in vitro study indicated that the anti-inflammatory function of MSCs on SF nanofibers was mediated through enhanced COX-2-PGE₂ production, as indomethacin completely abrogated PGE₂ production and decreased the survival rate of septic mice. Thus, SF nanofiber scaffolds potentiated the anti-inflammatory and immunomodulatory functions of MSCs, and were beneficial as a culture platform for the cell therapy of inflammatory disorders.

Investigating the effects of IDO1, PTGS2, and TGF-β1 overexpression on immunomodulatory properties of hTERT-MSCs and their extracellular vesicles

The therapeutic potential of mesenchymal stem cells (MSCs) is out of the question. Yet, recent drawbacks have resulted in a strategic shift towards the application of MSC-derived cell-free products such as extracellular vesicles (EVs). Recent reports revealed that functional properties of MSCs, including EV secretion patterns, correlate with microenvironmental cues. These findings highlight the urgent need for defining the optimal circumstances for EV preparation. Considering the limitations of primary cells, we employed immortalized cells as an alternative source to prepare therapeutically sufficient EV numbers. Herein, the effects of different conditional environments are explored on human TERT-immortalized MSCs (hTERT-MSCs). The latter were transduced to overexpress IDO1, PTGS2, and TGF-β1 transgenes either alone or in combination, and their immunomodulatory properties were analyzed thereafter. Likewise, EVs derived from these various MSCs were extensively characterized. hTERT-MSCs-IDO1 exerted superior inhibitory effects on lymphocytes, significantly more than hTERT-MSCs-IFN-γ. As such, IDO1 overexpression promoted the immunomodulatory properties of such enriched EVs. Considering the limitations of cell therapy like tumor formation and possible immune responses in the host, the results presented herein might be considered as a feasible model for the induction of immunomodulation in off-the-shelf and cell-free therapeutics, especially for autoimmune diseases.

Inhibition of complement C5a receptor protects lung cells and tissues against lipopolysaccharide-induced injury via blocking pyroptosis

Acute lung injury (ALI) is the injury of alveolar epithelial cells and capillary endothelial cells caused by various factors. Complement system and pyroptosis have been proved to be involved in ALI, and inhibition of C5a/C5a receptor (C5aR) could alleviate ALI. This study aimed to investigate whether C5a/C5aR inhibition could protect against LPS-induced ALI via mediating pyroptosis. Rats were assigned into four groups: Control, LPS, LPS+W-54011 1mg/kg, and LPS+W-54011 5mg/kg. Beas-2B cells pretreated with or without C5a and W-54011, alone and in combination, were challenged with LPS+ATP. Results unveiled that LPS caused lung tissue injury and inflammatory response, increased pyroptotic and apoptotic factors, along with elevated C5a concentration and C5aR expressions. However, W-54011 pretreatment alleviated lung damage and pulmonary edema, reduced inflammation and prevented cell pyroptosis. In vitro studies confirmed that LPS+ATP reduced cell viability, promoted cell death, generated inflammatory factors and promoted expressions of pyroptosis-related proteins, which could be prevented by W-54011 pretreatment while intensified by C5a pretreatment. The co-treatment of C5a and W-54011 could blunt the effects of C5a on LPS+ATP-induced cytotoxicity. In conclusion, inhibition of C5a/C5aR developed protective effects against LPS-induced ALI and the cytotoxicity of Beas-2B cells, and these effects may depend on blocking pyroptosis.

'Primed' Mesenchymal Stem Cells: a Potential Novel Therapeutic for COVID19 Patients

The COVID19 pandemic, designated as a public health crisis by the World Health Organization (WHO), is rapidly spreading around the world impacting the health and economy of almost all the countries. The data of hospitalized COVID19 patients, especially those with serious illness, indicate the involvement of immunopathological complications. As no effective treatment is currently available, we propose ‘Primed’ Mesenchymal Stem Cells (MSCs) as a therapeutic alternative to tackle devastating epidemic. The individual response to MSCs treatment is heterogeneous. During the treatment of infectious pathology, the effectiveness of the treatment may vary based on the disease scenario. Interestingly, when transplanted in vivo, MSCs are governed by the locally regulated microenvironment, suggesting that the restorative variability could be tailored by choosing a priming regimen to specifically correct a given pathology. Therefore, in our opinion, the priming of MSCs could be a novel approach to improve the responses of COVID19 patients.

A streamlined proliferation assay using mixed lymphocytes for evaluation of human mesenchymal stem cell immunomodulation activity

BACKGROUND

Mesenchymal stromal cells (MSCs) have been proposed for treatment of acute respiratory distress syndrome (ARDS), graft versus host disease (GVHD), wound healing and trauma. A consensus is building that immunomodulation by MSCs is important for therapeutic potential. MSCs suppress peripheral blood mononuclear cell (PBMC) proliferation in vitro, potentially reflecting an ability to suppress PBMC inflammatory responses in vivo. Current mixed lymphocyte reaction (MLR) assays commonly used to evaluate MSC potency generally rely on either direct co-culture or indirect culture using transwell systems for monitoring the proliferation of isolated PBMCs in the presence of mitotically inactive MSCs. Proliferation of PBMCs is monitored by several methods, including incorporation of radiolabeled nucleotides, BRDU labeling and ELISA assay or flow cytometry of carboxyfluorescein labeled PBMCs. Here we present a streamlined assay using MSCs in a direct co-culture system with unmodified MSCs using a luminescent ATP assay to evaluate both PBMC and MSC proliferation/survival.

METHODS

PBMCs were isolated from fresh anti-coagulated whole blood by centrifugation over Ficoll-Paque in LeucoSep tubes. Isolated PBMCs from 8 to 10 donors were pooled and cryopreserved at 1 × 10⁷/ml in 50% RPMI medium,10% DMSO, 40% human AB serum. MSCs derived from bone marrow, adipose tissue or umbilical cord (BM-MSC, Ad-MSC, UC-MSC, respectively) were serially diluted starting at 50-60,000 cells/well and cultured in 96 well plates for 4-48 h in their respective medium. On Day 0, MSCs were washed, resuspended in PBMC media (RPMI with 10% FBS, 2 mM Glutamine, 10 mM HEPES, pH 7.4) and incubated with or without 150,000 freshly thawed pooled PBMCs/well, in the presence or absence of phytohemagglutinin A (PHA, 0-5 μg/ml). Proliferation of both MSCs (adherent) and PBMCs (non-adherent) was assessed by quantitation of ATP levels using the bioluminescent reagent Cell Titer-Glo (Promega). Culture supernatant contained PBMC, while washed adherent cells were primarily MSCs. Both cell types were incubated for 30 min with an equal volume of Cell Titer-Glo reagent and then assayed in white plates on a luminescence plate reader.

RESULTS

PBMC proliferation in response to PHA stimulation resulted in a robust increase in ATP by 72 h, with >6 fold increase over unstimulated PBMCs, which showed no increase. MSC proliferation was decreased <20% at the highest PHA concentrations. Co-culture with MSCs suppressed PBMC proliferation dependent upon MSC passage number, source, and prior growth conditions. Total time to complete the ATP assay was under an hour including incubations. With minimal manipulations in the assay, intra- and inter- assay variations averaged 11.1 and 15.7% respectively.

CONCLUSIONS

Direct co-culture of live unmodified MSCs with freshly thawed pooled PBMCs gives a robust determination of immunosuppression by MSCs with unparalleled ease. Graded responses can be determined, allowing comparison of potency between MSC preparations as in comparisons between freshly thawed and cultured MSCs as well as interferon-γ licensed MSCs. With the 96 well plate assay, far fewer PBMCs are generally required than in a typical flow cytometry determination. This streamlined assay can be performed within 72 h, without irradiating cells and without specialized equipment.

Umbilical Cord-Derived CD362+ Mesenchymal Stromal Cells Attenuate Polymicrobial Sepsis Induced by Caecal Ligation and Puncture

Mesenchymal stromal cells (MSCs) have a multimodal, immunomodulatory mechanism of action and are now in clinical trials for single organ and systemic sepsis. However, a number of practicalities around source, homogeneity and therapeutic window remain to be determined. Here, we utilised conditioned medium from CD362⁺-sorted umbilical cord-human MSCs (UC-hMSCs) for a series of in vitro anti-inflammatory assays and the cryopreserved MSCs themselves in a severe (Series 1) or moderate (Series 2+3) caecal ligation and puncture (CLP) rodent model. Surviving animals were assessed at 48 h post injury induction. MSCs improved human lung, colonic and kidney epithelial cell survival following cytokine activation. In severe systemic sepsis, MSCs administered at 30 min enhanced survival (Series 1), and reduced organ bacterial load. In moderate systemic sepsis (Series 2), MSCs were ineffective when delivered immediately or 24 h later. Of importance, MSCs delivered 4 h post induction of moderate sepsis (Series 3) were effective, improving serum lactate, enhancing bacterial clearance from tissues, reducing pro-inflammatory cytokine concentrations and increasing antimicrobial peptides in serum. While demonstrating benefit and immunomodulation in systemic sepsis, therapeutic efficacy may be limited to a specific point of disease onset, and repeat dosing, MSC enhancement or other contingencies may be necessary.

Mesenchymal stem cells alleviate LPS-induced acute lung injury by inhibiting the proinflammatory function of Ly6C+ CD8+ T cells

Systemic inflammatory processes, including alveolar injury, cytokine induction, and neutrophil accumulation, play key roles in the pathophysiology of acute lung injury (ALI). The immunomodulatory effects of mesenchymal stem cells (MSCs) can contribute to the treatment of inflammatory disorders. In previous studies, the focus was on innate immune cells and the effects of MSCs on ALI through CD8⁺ T cells remain unclear. In the present study, lipopolysaccharide (LPS) was used to induce ALI in mice. ALI mice were treated with MSCs via intratracheal instillation. Survival rate, histopathological changes, protein levels, total cell count, cytokine levels, and chemokine levels in alveolar lavage fluid were used to determine the efficacy of MSCs. Mass cytometry and single-cell RNA sequencing (scRNA-seq) were used to characterize the CD8⁺ T cells in the lungs. Ly6C^- CD8⁺ T cells are prevalent in normal mice, whereas a specialized effector phenotype expressing a high level of Ly6C is predominant in advanced disease. MSCs significantly mitigated ALI and improved survival. MSCs decreased the infiltration of CD8⁺ T cells, especially Ly6C⁺ CD8⁺ T cells into the lungs. Mass cytometry revealed that CD8⁺ T cells expressing high Ly6C and CXCR3 levels caused tissue damage in the lungs of ALI mice, which was alleviated by MSCs. The scRNA-seq showed that Ly6C⁺ CD8⁺ T cells exhibited a more activated phenotype and decreased expression of proinflammatory factors that were enriched the most in immune chemotaxis after treatment with MSCs. We showed that CD8⁺ T cells play an important role in MSC-mediated ALI remission, and both infiltration quantity and proinflammatory function were inhibited by MSCs, indicating a potential mechanism for therapeutic intervention.

Adipose-derived mesenchymal stem cells attenuate acute lung injury and improve the gut microbiota in septic rats

Background

We hypothesized that adipose-derived mesenchymal stem cells (ADMSCs) may ameliorate sepsis-induced acute lung injury (ALI) and change microorganism populations in the gut microbiota, such as that of Firmicutes and Bacteroidetes.

Methods

A total of 60 male adult Sprague-Dawley (SD) rats were separated into three groups: the sham control (SC) group, the sepsis induced by cecal ligation and puncture (CLP) group, and the ADMSC treatment (CLP-ADMSCs) group, in which rats underwent the CLP procedure and then received 1 × 10⁶ ADMSCs. Rats were sacrificed 24 h after the SC or CLP procedures. To study the role of ADMSCs during ALI caused by sepsis and examine the impact of ADMSCs on the gut microbiome composition, rat lungs were histologically evaluated using hematoxylin and eosin (H&E) staining, serum levels of pro-inflammatory factors were detected using enzyme-linked immunosorbent assay (ELISA), and fecal samples were collected and analyzed using 16S rDNA sequencing.

Results

The serum levels of inflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-6, were significantly increased in rats after the CLP procedure, but were significantly decreased in rats treated with ADMSCs. Histological evaluation of the rat lungs yielded results consistent with the changes in IL-6 levels among all groups. Treatment with ADMSCs significantly increased the diversity of the gut microbiota in rats with sepsis. The principal coordinates analysis (PCoA) results showed that there was a significant difference between the gut microbiota of the CLP-ADMSCs group and that of the CLP group. In rats with sepsis, the proportion of Escherichia–Shigella (P = 0.01) related to lipopolysaccharide production increased, and the proportion of Akkermansia (P = 0.02) related to the regulation of intestinal mucosal thickness and the maintenance of intestinal barrier function decreased. These changes in the gut microbiota break the energy balance, aggravate inflammatory reactions, reduce intestinal barrier functions, and promote the translocation of intestinal bacteria. Intervention with ADMSCs increased the proportion of beneficial bacteria, reduced the proportion of harmful bacteria, and normalized the gut microbiota.

Conclusions

Therapeutically administered ADMSCs ameliorate CLP-induced ALI and improves gut microbiota, which provides a potential therapeutic mechanism for ADMSCs in the treatment of sepsis.

Non-coding RNAs and Exosomes: Their Role in the Pathogenesis of Sepsis

Sepsis is characterized as an uncontrolled host response to infection, and it represents a serious health challenge, causing excess mortality and morbidity worldwide. The discovery of sepsis-related epigenetic and molecular mechanisms could result in improved diagnostic and therapeutic approaches, leading to a reduced overall risk for affected patients. Accumulating data show that microRNAs, non-coding RNAs, and exosomes could all be considered as novel diagnostic markers for sepsis patients. These biomarkers have been demonstrated to be involved in regulation of sepsis pathophysiology. However, epigenetic modifications have not yet been widely reported in actual clinical settings, and further investigation is required to determine their importance in intensive care patients. Further studies should be carried out to explore tissue-specific or organ-specific epigenetic RNA-based biomarkers and their therapeutic potential in sepsis patients.

Alleviation of acute radiation-induced bone marrow failure in mice with human fetal placental stromal cell therapy

Purpose

Selected placental mesenchymal stromal cells isolated from the fetal mesenchymal placental tissues (f-hPSCs) were tested as cell therapy of lethal acute radiation syndrome (ARS) with bone marrow regeneration and induced extramedullary hematopoiesis.

Methods and materials

f-hPSCs were isolated from the chorionic plate of human placentae and further expanded in regular culture conditions. 2 × 10⁶ f-hPSCs were injected on days 1 and 4 to 8-Gy total body irradiated (TBI) C3H mice, both intramuscularly and subcutaneously. Pre-splenectomized TBI mice were used to test the involvement of extramedullary spleen hematopoiesis in the f-hPSC-induced hematopoiesis recovery in the TBI mice. Weight and survival of the mice were followed up within the morbid period of up to 23 days following irradiation. The role of hematopoietic progenitors in the recovery of treated mice was evaluated by flow cytometry, blood cell counts, and assay of possibly relevant growth factors.

Results and conclusions

The survival rate of all groups of TBI f-hPSC-treated mice at the end of the follow-up was dramatically elevated from < 10% in untreated to ~ 80%, with a parallel regain of body weight, bone marrow (BM) recovery, and elevated circulating progenitors of blood cell lineages. Blood erythropoietin levels were elevated in all f-hPSC-treated mice. Extramedullary splenic hematopoiesis was recorded in the f-hPSC-treated mice, though splenectomized mice still had similar survival rate. Our findings suggest that the indirect f-hPSC life-saving therapy of ARS may also be applied for treating other conditions with a failure of the hematopoietic system and severe pancytopenia.

Cell-Based Therapeutic Approaches for Cystic Fibrosis

Cystic Fibrosis (CF) is a chronic autosomal recessive disease caused by defects in the cystic fibrosis transmembrane conductance regulator gene (CFTR). Cystic Fibrosis affects multiple organs but progressive remodeling of the airways, mucus accumulation, and chronic inflammation in the lung, result in lung disease as the major cause of morbidity and mortality. While advances in management of CF symptoms have increased the life expectancy of this devastating disease, and there is tremendous excitement about the potential of new agents targeting the CFTR molecule itself, there is still no curative treatment. With the recent advances in the identification of endogenous airway progenitor cells and in directed differentiation of pluripotent cell sources, cell-based therapeutic approaches for CF have become a plausible treatment method with the potential to ultimately cure the disease. In this review, we highlight the current state of cell therapy in the CF field focusing on the relevant autologous and allogeneic cell populations under investigation and the challenges associated with their use. In addition, we present advances in induced pluripotent stem (iPS) cell approaches and emerging new genetic engineering methods, which have the capacity to overcome the current limitations hindering cell therapy approaches.

Mesenchymal stem cells combined with liraglutide relieve acute lung injury through apoptotic signaling restrained by PKA/β-catenin

Background

ARDS and ALI are life-threatening diseases with extremely high mortality in patients. Different sources of MSCs could mitigate the symptoms of ALI from diverse mechanisms. Liraglutide is an activator of glucagon-like peptide-1 receptor (GLP-1R) that activates anti-apoptotic pathways and exerts anti-inflammatory effects. We mainly compared the effects of human chorionic villus-derived mesenchymal stem cells (hCMSCs), human bone marrow-derived mesenchymal stem cells (hBMSCs), and human adipose-derived mesenchymal stem cells (hAMSCs) on the treatment of ALI and explored the apoptosis mechanism of combination MSCs of liraglutide.

Methods

The proliferation of MSCs was detected by MTT assay. Western blot and RT-qPCR were used to detect the expression of GLP-1R, SPC, Ang-1, and KGF in MSCs stimulated by LPS and liraglutide. By using flow cytometry and TUNEL assay to compare the apoptosis of three MSCs under the action of LPS and liraglutide, we selected hCMSCs as the target cells to study the expression of apoptotic protein through the PKA/β-catenin pathway. In ALI animal models, we observed the effects of liraglutide alone, MSCs alone, and MSCs combined with liraglutide by H&E staining, cell counting, immunohistochemistry, and ELISA assay.

Results

We demonstrated that LPS attenuates the proliferation of the three MSCs and the expression of GLP-1R. Liraglutide could reverse the effects of LPS; increase the expression of SPC, Ang-1, and KGF; and can reduce the apoptosis of three MSCs through the PKA/β-catenin pathway. In the LPS-induced ALI model, MSCs combined with liraglutide showed a significant therapeutic effect, and hCMSCs combined with liraglutide have advantages in the treatment of ALI.

Conclusions

The therapeutic effect of combination MSCs of liraglutide on ALI was higher than that of MSCs alone or liraglutide alone, and liraglutide could alleviate the symptoms of ALI by reducing MSCs apoptosis.

Comparative immunomodulatory properties of mesenchymal stem cells derived from human breast tumor and normal breast adipose tissue

OBJECTIVE

Mesenchymal stem cells (MSCs), one of the most important stromal cells in the tumor microenvironment, play a major role in the immunomodulation and development of tumors. In contrast to immunomodulatory effects of bone marrow-derived MSCs, resident MSCs were not well studied in tumor. The aim of this study was to compare the immunomodulatory properties and protein secretion profiles of MSCs isolated from breast tumor (T-MSC) and normal breast adipose tissue (N-MSC).

MATERIALS AND METHODS

T-MSCs and N-MSCs were isolated by the explant culture method and characterized, and their immunomodulatory function was assessed on peripheral blood lymphocytes (PBLs) by evaluating the effects of MSC conditioned media on the proliferation and induction of some cytokines and regulatory T cells (Tregs) by BrdU assay, ELISA, and flow cytometry. In addition, we compared the secretion of indoleamine 2,3-dioxygenase (IDO), vascular endothelial growth factor (VEGF), matrix metallopeptidase (MMP)-2, MMP-9, and Galectin-1.

RESULTS

T-MSCs showed a higher secretion of transforming growth factor beta (TGF-β), prostaglandin E2 (PGE2), IDO, and VEGF and lower secretion of MMP-2 and MMP-9 compared with N-MSCs. However, no significant difference was found in the secretion of interferon gamma (IFN-γ), interleukin 10 (IL10), IL4, IL17, and Galectin-1 in T-MSCs and N-MSCs. The immunomodulatory effect of soluble factors on PBLs showed that T-MSCs, in contrast to N-MSCs, stimulate PBL proliferation. Importantly, the ability of T-MSCs to induce IL10, TGF-β, IFN-γ, and PGE2 was higher than that of N-MSCs. In addition, T-MSCs and N-MSCs exhibited no significant difference in Treg induction.

CONCLUSION

MSCs educated in stage II breast cancer and normal breast adipose tissue, although sharing a similar morphology and immunophenotype, exhibited a clearly different profile in some immunomodulatory functions and protein secretions.

Use of Autologous Cord Blood Mononuclear Cells Infusion for the Prevention of Bronchopulmonary Dysplasia in Extremely Preterm Neonates: A Study Protocol for a Placebo-Controlled Randomized Multicenter Trial [NCT03053076]

Background: Despite the rapid advance of neonatal care, bronchopulmonary dysplasia (BPD) remains a significant burden for the preterm population, and there is a lack of effective intervention. Stem cell depletion because of preterm birth is regarded as one of the underlying pathological mechanisms for the arrest of alveolar and vascular development. Preclinical and small-sample clinical studies have proven the efficacy and safety of stem cells in treating and preventing lung injury. However, there are currently no randomized clinical trials (RCTs) investigating the use of autologous cord blood mononuclear cells (ACBMNC) for the prevention of BPD in premature infants. The purpose of this study is to investigate the effects of infusion of ACBMNC for the prevention of BPD in preterm neonates <28 weeks. Methods: In this prospective, randomized controlled double-blind multi-center clinical trial, 200 preterm neonates <28 weeks gestation will be randomly assigned to receive intravenous ACBMNC infusion (5 × 107 cells/kg) or placebo (normal saline) within 24 h after birth in a 1:1 ratio using a central randomization system. The primary outcome will be survival without BPD at 36 weeks of postmenstrual age or at discharge, whichever comes first. The secondary outcomes will include the mortality rate, other common preterm complication rates, respiratory support duration, length, and cost of hospitalization, and long-term outcomes after a 2-year follow-up. Conclusion: This will be the first randomized, controlled, blinded trial to evaluate the efficacy of ACBMNC infusion as a prevention therapy for BPD. The results of this trial will provide valuable clinical evidence for recommendations on the management of BPD in extremely preterm infants. Clinical Trial Registration: ClinicalTrials.gov, NCT03053076, registered 02/14/2017, retrospectively registered, https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S0006WN4&selectaction=Edit&uid=U0002PLA&ts=2&cx=9y23d4 (Additional File 2).

Microvesicles derived from human Wharton's jelly mesenchymal stem cells enhance autophagy and ameliorate acute lung injury via delivery of miR-100

Objectives

Microvesicles (MVs) derived from human Wharton’s jelly mesenchymal stem cells (MSC-MVs) were demonstrated to ameliorate acute lung injury (ALI). We have previously found that MSC-MV-transferred hepatocyte growth factor was partly involved in their therapeutic effects. Since MSC-MVs also contained a substantial quantity of miR-100, which plays an important role in lung cancer and injury, we speculated that miR-100 might similarly account for a part of the therapeutic effects of MSC-MVs.

Methods

MSCs were transfected with miR-100 inhibitor to downregulate miR-100 in MSC-MVs. A rat model of ALI and cell injury in rat type II alveolar epithelial cell line (L2) was induced by bleomycin (BLM). A co-culture model of alveolar epithelial cells and MSC-MVs was utilized to examine the therapeutic role of MSC-MVs and mechanism.

Results

MSC-MV treatment attenuated BLM-induced apoptosis and inflammation in BLM-treated L2 cells and ameliorated BLM-induced lung apoptosis, inflammation, and fibrosis in BLM-induced ALI rats. The beneficial effect of MSC-MVs was partly eliminated when miR-100 was knocked down in MSCs. Moreover, MSC-MV-transferred miR-100 mediated the therapeutic effect of MSC-MVs in ALI through enhancing autophagy by targeting mTOR.

Conclusion

MSC-MVs enhance autophagy and ameliorate ALI partially via delivery of miR-100.

Bone Marrow-derived Mesenchymal Stem Cells and Chronic Allograft Disease in a Bronchiolitis Obliterans Animal Model

INTRODUCTION

Bronchiolitis obliterans (BO) is the most common expression of chronic allograft dysfunction in lung transplantation. Moreover, BO represents the major cause of death in the long-term after this procedure. On the other hand, mesenchymal stem cells have been tested in animal models of BO aiming to interfere in its development. The aim of this experimental study is to explore the role of bone-marrow derived stem cells (BMSCs) as a preventive intervention of BO occurrence.

MATERIALS AND METHODS

This an experimental randomized study. A bronchiolitis obliterans animal model in rats was reproduced: heterotopical tracheal transplant model in lung parenchyma. Five of these animals were used as control group. After setting up the model, individuals were divided in 3 groups of treatment (n=15), in which BMSCs were administered in 3 different time points after the tracheal transplant (tracheal transplantation and BMSCs administration occurred the same day, group G0; after 7 days, group G7; after 14 days, group G14. In addition, within each group, BMSCs were administered through 3 different routes: endotracheally, endovascular and topically in the lung parenchyma). Animals were sacrificed at 21 days. Histology, fluorescence in situ hybridization and immunohistochemistry techniques were performed for identifying stem cells.

RESULTS

Compared to control group, animals receiving BMSCs showed large neovessels in a loose fibrous matrix. Group G7 showed less fibrosis (p<0.033) and edema (p<0.028). Moreover, G7 animals receiving stem cells endotracheally showed no fibrosis (p<0.008). Alveolar-like patches of tissue were observed among all groups (53.4%, 46.7% and 40% in G0, G7 and G14 respectively), consisting of cells expressing both stem and alveolar cells biomarkers.

CONCLUSION

BMSCs modify the course of bronchiolitis obliterans and differentiate into alveolar cells. Endotracheal administration of BMSCs 7 days after the heterotopical tracheal transplant might be considered an effective way to prevent BO in this animal model.

Allogeneic mesenchymal stromal cells: Novel therapeutic option for mutated FLNA-associated respiratory failure in the pediatric setting

BACKGROUND

Mesenchymal stromal cell (MSC)-mediated therapeutic effects have been observed in the treatment of lung diseases. For the first time, this treatment was used as rescue therapy in a pediatric patient with a life-threatening respiratory syndrome associated with the filamin A (FLNA) gene mutation.

METHODS

A child with a new pathogenic variant of the FLNA gene c.7391_7403del (p.Val2464AlafsTer5), at the age of 18 months, due to serious and irreversible chronic respiratory failure, was treated with repeated intravenous infusions of allogeneic bone marrow (BM)-MSCs. The child's respiratory condition was monitored. Immunologic studies before each MSC treatment were performed.

RESULTS

No acute adverse events related to the MSC infusions were observed. After the second infusion, the child's respiratory condition progressively improved, with reduced necessity for mechanical ventilation support. A thorax computed tomography (CT) scan showed bilateral recovery of the basal parenchyma, anatomical-functional alignment and aerial penetration improvement. After the first MSC administration, an increase in Th17 and FoxP3⁺ T percentages in the peripheral blood was observed. After the second MSC infusion, a significant rise in the Treg/Th17 ratio was noted, as well as an increased percentage of CD20⁺ /CD19⁺ B lymphocytes and augmented PHA-induced proliferation.

DISCUSSION

MSC infusions are a promising therapeutic modality for patients in respiratory failure, as observed in this pediatric patient with an FLNA mutation. MSCs may have an immunomodulatory effect and thus mitigate lung injury; although in this case, MSC antimicrobial effects may have synergistically impacted the clinical improvements. Further investigations are planned to establish the safety and efficacy of this treatment option for interstitial lung diseases in children.

Autologous cord blood cell infusion in preterm neonates safely reduces respiratory support duration and potentially preterm complications

Preterm birth and its complications are the leading cause of neonatal death. The main underlying pathological mechanisms for preterm complications are disruption of the normal maturation processes within the target tissues, interrupted by premature birth. Cord blood, as a new and convenient source of stem cells, may provide new, promising options for preventing preterm complications. This prospective, nonrandomized placebo controlled study aimed at investigating the effect of autologous cord blood mononuclear cells (ACBMNC) for preventing preterm associated complications. Preterm infants less than 35 weeks gestational age were assigned to receive ACBMNC (5 × 10⁷ cells/kg) intravenous or normal saline within 8 hours after birth. Preterm complication rates were compared between two groups to demonstrate the effect of ACBMNC infusion in reducing preterm complications. Fifteen preterm infants received ACBMNC infusion, and 16 infants were assigned to the control group. There were no significant differences when comparing mortality and preterm complication rates before discharge. However, ACBMNC infusion demonstrated significant decreases in duration of mechanical ventilation (3.2 days vs 6.41 days, P = .028) and oxygen therapy (5.33 days vs 11.31 days, P = .047). ACBMNC infusion was effective in reducing respiratory support duration in very preterm infants. Due to the limited number of patients enrolled, powered randomized controlled trials are needed to better define its efficacy.

Mesenchymal Stromal Cells Modulate Peripheral Stress-Induced Innate Immune Activation Indirectly Limiting the Emergence of Neuroinflammation-Driven Depressive and Anxiety-like Behaviors

BACKGROUND

Hyperactivation of innate immunity has been implicated in the etiology of mood disorders, including major depressive disorder (MDD). Mesenchymal stromal cells (MSCs) have demonstrated potent immunomodulatory capabilities in the context of chronic inflammatory disease and injury but have yet to be evaluated in stress-based preclinical models of MDD. We sought to test the ability of intravenous MSCs to modulate innate immune activation and behavioral patterns associated with repeated social defeat (RSD).

METHODS

Murine RSD-induced innate immune activation as well as depressive and anxiety-like behaviors were assessed in unstressed, RSD, and RSD + human MSC groups. Biodistribution and fate studies were performed to inform potential mechanisms of action.

RESULTS

MSCs reduced stress-induced circulating proinflammatory cytokines, monocytes, neuroinflammation, and depressive and anxiety-like behaviors. Biodistribution analyses indicated that infused MSCs distributed within peripheral organs without homing to the brain. Murine neutrophils targeted MSCs in the lungs within hours of administration. MSCs and recipient neutrophils were cleared by recipient macrophages promoting a switch toward a regulatory phenotype and systemic resolution of inflammation.

CONCLUSIONS

Peripheral delivery of MSCs modulates central nervous system inflammatory processes and aberrant behavioral patterns in a stress-based rodent model of MDD and anxiety. Recent studies suggest that host immune cell-mediated phagocytosis of MSCs in vivo can trigger an immunomodulatory cascade, resulting in resolution of inflammation. Our data suggest that similar mechanisms may protect distal organs, including the brain, from systemic, stress-induced proinflammatory spikes and may uncover unexpected targets in the periphery for novel or adjunct treatment for a subset of patients with MDD.

Penehyclidine Hydrochloride Alleviates Lipopolysaccharide-Induced Acute Lung Injury by Ameliorating Apoptosis and Endoplasmic Reticulum Stress

BACKGROUND

Penehyclidine hydrochloride (PHC), a novel anticholinergic reagent, has been shown to exert anti-endoplasmic reticulum stress (ERS), antioxidant, and antiinflammation functions in various rat models. However, the definite pathogenesis of lung defensive roles of PHC remains unclear. This study measured the functions of PHC on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats.

METHODS

In this research, the LPS-induced ALI model was assessed through the branchial injection of LPS for 24 h. Male Sprague-Dawley rats were randomly allocated into 5 groups: sham, LPS, LPS + PHC (0.5 mg/kg), LPS + PHC (1 mg/kg), and LPS + PHC (2.5 mg/kg). The concentrations of superoxide dismutase, malondialdehyde, myeloperoxidase, and glutathione peroxidase were measured by enzyme-linked immunosorbent assay and immunohistochemistry analysis. Western blotting, real-time PCR, and immunofluorescence analysis were used to determine the ERS-associated protein levels and mRNA expression. The protein levels of Bax, Bcl-2, caspase-3, and caspase-9 were used to measure lung tissue apoptosis.

RESULTS

The results revealed that PHC administration inhibited LPS-induced ALI as indicated by the loss in the ratio of injury production evaluated through hematoxylin-eosin staining, in particular the lung sample sections, compared with the LPS group. PHC administration inhibited LPS-induced lung myeloperoxidase and serum concentrations of malondialdehyde, superoxide dismutase, and glutathione peroxidase in rats. PHC administration repressed the LPS-activated ERS-correlated pathway and apoptosis-associated protein levels in rats.

CONCLUSIONS

In summary, our findings indicated that PHC has a defensive effect on LPS-induced ALI by inhibiting oxidative stress, attenuating PERK and ATF6 signals, and suppressing ERS-mediated apoptosis.

Microvesicles derived from human Wharton's Jelly mesenchymal stem cells ameliorate acute lung injury partly mediated by hepatocyte growth factor

Several studies have highlighted the underlying role of mesenchymal stem cells microvesicles (MSC-MVs) in acute lung injury (ALI). Hepatocyte growth factor (HGF) derived from MSC-MVs is partly involved in their therapeutic effects; however, the detailed mechanism remains unclear. MVs were isolated from human Wharton's Jelly MSCs. The rat model of ALI was established by intratracheal instillation of bleomycin (BLM). A co-culture model of alveolar epithelial cells or pulmonary endothelial cells and MSC-MVs was utilized. Total protein content in bronchoalveolar lavage fluid (BALF) was determined by bicinchoninic acid method. White blood cell (WBC) and neutrophil in BALF were counted. ELISA was used for the determination of cytokines and HGF in BALF. Apoptosis was determined by TUNEL assay and Annexin V-FITC/PI staining as well as caspase-3 activity detection. HE and Masson staining of lung tissues was used for histopathology analysis. The expression of HGF and proteins involved in the PI3K/AKT/mTOR pathway were measured by quantitative Real-Time PCR (qRT-PCR) and western blotting. Treatment with MSC-MVs significantly inhibited BLM-induced apoptosis and fibrosis in lung tissues and PI3K/AKT/mTOR activation, which was reversed by HGF mRNA deficient MVs. Intriguingly, these effects were completely abrogated by PI3K inhibitor. The therapeutic effect of MSC-MVs in ALI was partly mediated through HGF mRNA.

Human Adipose-Derived Mesenchymal Stem Cells Modify Lung Immunity and Improve Antibacterial Defense in Pneumosepsis Caused by Klebsiella pneumoniae

Adult mesenchymal stem cells exert immunomodulatory effects that might improve the host response during sepsis. Knowledge on the effect of adipose-derived mesenchymal stem cells (ASCs) in sepsis is limited. Klebsiella (K.) pneumoniae is a common cause of gram-negative pneumonia and sepsis. This study sought to determine the effect of human ASCs on the host response during pneumosepsis in mice. Mice were infected with K. pneumoniae via the airways to induce a gradually evolving infection in the lung culminating pneumosepsis. One or 6 hours after infection, mice were infused intravenously with ASCs or vehicle, and euthanized after 16 hours or 48 hours, respectively. The effects of freshly cultured and cryopreserved ASCs were compared, the latter formulation being more clinically relevant. Intravenously administered ASCs were visualized in lung tissue by immunostaining at 1 and 3 hours, but not at 15 hours after infusion. Although early after infection, ASCs did not or only modestly influence bacterial loads, they reduced bacterial burdens in lungs and distant organs at 48 hours. ASCs reduced the lung levels of pro-inflammatory cytokines and attenuated lung pathology, but did not influence distant organ injury. ASCs strongly modified the lung transcriptome in uninfected mice and especially mice with pneumosepsis. Cryopreserved and cultured ASCs induced largely similar effects on the lung transcriptome. These data indicate that human ASCs induce profound immune modulatory effects in the lungs, resulting in reduced bacterial burdens and lung inflammation during pneumosepsis caused by a common human pathogen, suggesting that ASCs may be an adjunctive therapeutic in this condition. Stem Cells Translational Medicine 2019;8:785&796.

A proof-of-concept clinical trial using mesenchymal stem cells for the treatment of corneal epithelial stem cell deficiency

Ocular stem cell transplantation derived from either autologous or allogeneic donor corneoscleral junction is a functional cell therapy to manage extensive and/or severe limbal stem cell deficiencies that lead to corneal epithelial failure. Mesenchymal stem cells have been properly tested in animal models of this ophthalmic pathology, but never in human eyes despite their potential advantages. We conducted a 6- to 12-month proof-of-concept, randomized, and double-masked pilot trial to test whether allogeneic bone marrow-derived mesenchymal stem cell transplantation (MSCT], n = 17) was as safe and as equally efficient as allogeneic cultivated limbal epithelial transplantation (CLET), (n = 11) to improve corneal epithelial damage due to limbal stem cell deficiency. Primary endpoints demanded combination of symptoms, signs, and the objective improvement of the epithelial phenotype in central cornea by in vivo confocal microscopy. This proof-of-concept trial showed that MSCT was as safe and efficacious as CLET. Global success at 6-12 months was 72.7%-77.8% for CLET cases and 76.5%-85.7% for MSCT cases (not significant differences). Central corneal epithelial phenotype improved in 71.4% and 66.7% of MSCT and CLET cases, respectively at 12 months (P = 1.000). There were no adverse events related to cell products. This trial suggests first evidence that MSCT facilitated improvement of a diseased corneal epithelium due to lack of its stem cells as efficiently as CLET. Consequently, not only CLET but also MSCT deserves more preclinical investigational resources before the favorable results of this proof-of-concept trial could be transformed into the larger numbers of the multicenter trials that would provide stronger evidence. (ClinicalTrials.gov number, NCT01562002.).

Protective effects of CXCR3/HO‑1 gene‑modified BMMSCs on damaged intestinal epithelial cells: Role of the p38‑MAPK signaling pathway

The purpose of the present study was to investigate whether bone marrow mesenchymal stem cells (BMMSCs) modified by CXC-chemokine receptor type 3 (CXCR3) and heme oxygenase-1 (HO-1) genes can repair damaged intestinal epithelial cells in vitro, and the role of the p38 mitogen-activated protein kinase (p38-MAPK) pathway in this process. A model of intestinal epithelial crypt cell line-6 (IEC-6) damage was created, and BMMSCs were transfected with either the CXCR3 and/or HO-1 gene in vitro. There were nine experimental groups in which the damaged IEC-6 cells were co-cultured with differentially-treated BMMSCs and lymphocytes for 24 h. Reverse transcription-quantitative polymerase chain reaction analysis, immunohistochemistry and a western blot analysis were performed to detect stem cell transfection, the repair of damaged intestinal epithelial cells and the expression of related molecules in the P38-MAPK pathway, respectively. Crystal violet staining and live cell imaging were used to detect the chemotaxis of BMMSCs. Flow cytometry was used to detect T lymphocyte activity and the surface markers expressed on BMMSCs. An ELISA was used to quantify cytokine production. The adenovirus (Ad)-CXCR3/MSCs exhibited the characteristics of stem cells and exhibited chemotaxis. The Ad-CXCR3/MSCs and Ad-(CXCR3 + HO)/MSCs exhibited increased expression of tight junction protein zonula occludens-1 (ZO-1) and anti-proliferating cell nuclear antigen in the damaged IEC-6 cells, and apoptosis of the damaged IEC-6 cells was decreased. BMMSCs inhibited the phosphorylation of p38, in addition to downstream molecules of the p38MAPK signaling pathway. The Ad-CXCR3/MSCs and Ad-(CXCR3 + HO)/MSCs exhibited significantly decreased expression levels of downstream molecules, including phosphorylated (p)-p38, p-activated transcription factor 2, p-C/EBP homologous protein-10, and p-myocyte enhancer factor 2C, and target molecules (e.g., apoptotic bodies). The effects of Ad-(CXCR3 + HO)/MSCs on the repair of the damaged intestinal tract and inhibition of the p38-MAPK pathway was more marked than those in other groups on day 7 post-surgery in the rejection model for small bowel transplantation. BMMSCs modified by the CXCR3 and HO-1 genes exhibited superior ability to repair damaged intestinal epithelial cells and served this role via the p38-MAPK pathway.

CXCR4-Overexpressing Umbilical Cord Mesenchymal Stem Cells Enhance Protection against Radiation-Induced Lung Injury

Less quantity of transplanted mesenchymal stem cells (MSCs) influences the therapeutic effects on radiation-induced lung injury (RILI). Previous studies have demonstrated that MSCs overexpressing Chemokine (C-X-C motif) receptor 4 (CXCR4) could increase the quantity of transplanted cells to local tissues. In the present study, we conducted overexpressing CXCR4 human umbilical cord mesenchymal stem cell (HUMSC) therapy for RILI. C57BL mice received single dose of thoracic irradiation with 13 Gy of X-rays and then were administered saline, control HUMSCs, or CXCR4-overexpressing HUMSCs via tail vein. Transfection with CXCR4 enhanced the quantity of transplanted HUMSCs in the radiation-induced injured lung tissues. CXCR4-overexpressing HUMSCs not only improved histopathological changes but also decreased the radiation-induced expression of SDF-1, TGF-β1, α-SMA, and collagen I and inhibited the radiation-induced decreased expression of E-cadherin. Transplanted CXCR4-overexpressing HUMSCs also could express pro-SP-C, indicated adopting the feature of ATII. These finding suggests that CXCR4-overexpressing HUMSCs enhance the protection against RILI and may be a promising strategy for RILI treatment.

Mesenchymal stem cells overexpressing heme oxygenase-1 ameliorate lipopolysaccharide-induced acute lung injury in rats

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are common and potentially lethal clinical syndromes characterized by acute respiratory failure resulting from excessive pulmonary inflammation, noncardiogenic pulmonary edema, and alveolar-capillary barrier disruption. At present, there is no effective and specific therapy for ALI/ARDS. Mesenchymal stem cells (MSCs) have well-known therapeutic potential in patients with ALI/ARDS. Heme oxygenase-1 (HO-1), a cytoprotective enzyme, possesses antioxidative, anti-inflammatory, and antiapoptotic effects. Thus, a combination of MSC transplantation with HO-1 delivery may have an additional protective effect against ALI/ARDS. This study investigated the effect of HO-1-modified bone-marrow-derived MSCs (MSCs-HO-1) on lipopolysaccharide (LPS)-induced ALI and its underlying mechanisms. We established MSCs-HO-1 through lentiviral transduction. The ALI rat model was established by successive LPS inhalations following injection with MSCs-HO-1. The survival rate, histological changes in the lungs, total protein concentration and neutrophil counts in bronchoalveolar lavage fluid, lung wet/dry weight ratio, cytokine levels in serum and lungs, nuclear transcription factor-κB activity, and protein expression of Toll-like receptor 4 signaling adaptors were examined. Furthermore, the cell viability, apoptosis, and paracrine activity of MSCs-HO-1 were examined under inflammatory stimuli in vitro. MSCs-HO-1 injection improved these parameters compared with primary unmodified MSCs. Moreover, MSCs-HO-1 had superior prosurvival and antiapoptotic properties and enhanced paracrine functions in vitro. Therefore, MSCs-HO-1 exert an enhanced protective effect to alleviate LPS-induced ALI in rats, and the mechanisms may be partially associated with superior prosurvival, antiapoptosis, and enhanced paracrine functions of MSCs-HO-1. These findings provide a novel insight into MSC-based therapeutic strategies for treating ALI/ARDS.

Lung transplantation, ex-vivo reconditioning and regeneration: state of the art and perspectives

Lung transplantation is the only therapeutic option for end-stage pulmonary failure. Nevertheless, the shortage of donor pool available for transplantation does not allow to satisfy the requests, thus the mortality on the waiting list remains high. One of the tools to overcome the donor pool shortage is the use of ex-vivo lung perfusion (EVLP) to preserve, evaluate and recondition selected lung grafts not otherwise suitable for transplantation. EVLP is nowadays a clinical reality and have several destinations of use. After a narrative review of the literature and looking at our experience we can assume that one of the chances to improve the outcome of lung transplantation and to overcome the donor pool shortage could be the tissue regeneration of the graft during EVLP and the immunomodulation of the recipient. Both these strategies are performed using mesenchymal stem cells (MSC). The results of the models of lung perfusion with MSC-based cell therapy open the way to a new innovative approach that further increases the potential for using of the lung perfusion platform.

Tracking of transplanted human umbilical cord-derived mesenchymal stem cells labeled with fluorescent probe in a mouse model of acute lung injury

The aim of the present study was topreliminarily visualize the distribution of humanumbilical cord-derived-mesenchymal stem cells (hUC-MSCs) in treating acute lung injury (ALI) using a targeted fluorescent technique. Anovel fluorescent molecule probe was first synthesized via the specific binding of antigen and antibody in vitro to label the hUC-MSCs. Two groups of mice, comprising a normal saline (NS)+MSC group and lipopolysaccharide (LPS)+MSC group, were subjected to optical imaging. At 4 h following ALI mouse model construction, the labeled hUC-MSCs were transplanted into the mice in the NS+MSC group and LPS+MSC group by tail vein injection. The mice were sacrificed 30 min, 1 day, 3 days and 7 days following injection of the labeled hUC-MSCs, and the lungs, heart, spleen, kidneys and liver were removed. The excised lungs, heart, spleen, kidneys and liver were then detected on asmall animal fluorescent imager. The fluorescent results showed that the signal intensity in the lungs of the LPS+MSC group was significantly higher, compared with that of the NS+MSC group at 30 min (3.53±0.06×10⁻⁴, vs. 1.95±0.05×10⁻⁴ scaled counts/sec), 1 day (36.20±0.77×10⁻⁴, vs. 23.45±0.43×10⁻⁴ scaled counts/sec), 3 days (11.83±0.26×10⁻⁴, vs. 5.39±0.10×10⁻⁴ scaled counts/sec), and 7 days (3.14±0.04×10⁻⁴, vs. 0.00±0.00×10⁻⁴ scaled counts/sec; all P<0.05). The fluorescence intensity in the liver of the LPS+MSC group, vs. NS+MSC group was measured at 30 min (0.00±0.00×10⁻⁴, vs. 0.00±0.00×10⁻⁴ scaled counts/sec); 1 day (5.53±0.08×10⁻⁴, vs. 5.44±0.16×10⁻⁴ scaled counts/sec); 3 days (0.00±0.00×10⁻⁴, vs. 8.67±0.05×10⁻⁴ scaled counts/sec); 7 days (0.00±0.00×10⁻⁴, vs. 0.00±0.00×10⁻⁴ scaled counts/sec). The signal intensity of the heart, spleen and kidneys was minimal. In conclusion, the novel targeted fluorescence molecular probe was suitable for tracking the distribution processes of hUC-MSCs in treating ALI.

Anti-inflammatory roles of mesenchymal stromal cells during acute Streptococcus pneumoniae pulmonary infection in mice

BACKGROUND

Pneumonia is the fourth leading cause of death worldwide, and Streptococcus pneumoniae is the most commonly associated pathogen. Increasing evidence suggests that mesenchymal stromal cells (MSCs) have anti-inflammatory roles during innate immune responses such as sepsis. However, little is known about the effect of MSCs on pneumococcal pneumonia.

METHODS

Bone marrow-derived macrophages (BMDMs) were stimulated with various ligands in the presence or absence of MSC-conditioned medium. For in vivo studies, mice intranasally-inoculated with S. pneumoniae were intravenously treated with MSCs or vehicle, and various parameters were assessed.

RESULTS

After stimulation with toll-like receptor (TLR) 2, TLR9 or TLR4 ligands, or live S. pneumoniae, TNF-α and interleukin (IL)-6 levels were significantly decreased, whereas IL-10 was significantly increased in BMDMs cultured in MSC-conditioned medium. In mice, MSC treatment decreased the number of neutrophils in bronchoalveolar lavage fluid (BALF) after pneumococcal infection, and this was associated with a decrease in myeloperoxidase activity in the lungs. Levels of proinflammatory cytokines, including TNF-α, IL-6, GM-CSF and IFN-γ, were significantly lower in MSC-treated mice, and the bacterial load in the lung after pneumococcal infection was significantly reduced. In addition, histopathologic analysis confirmed a decrease in the number of cells recruited to the lungs; however, lung edema, protein leakage into the BALF and levels of the antibacterial protein lipocalin 2 in the BALF were comparable between the groups.

CONCLUSIONS

These results indicate that MSCs could represent a potential therapeutic application for the treatment of pneumonia caused by S. pneumoniae.

Comparative Effects of Umbilical Cord- and Menstrual Blood-Derived MSCs in Repairing Acute Lung Injury

Mesenchymal stem cells (MSCs) can effectively relieve acute lung injury (ALI) in several in vivo models. However, the underlying mechanisms and optimal sources of MSCs are unclear. In the present study, we investigated the effects of umbilical cord- (UC-) and menstrual blood- (MB-) derived MSCs on ALI. MSCs were transplanted into a lipopolysaccharide-induced ALI mouse model, and the therapeutic effects were determined by histological, cellular, and biochemical analyses. Our results showed that both UCMSC and MBMSC transplantation inhibited the inflammatory response and promoted lung tissue repair. UCMSC treatment resulted in reduced damage and inflammation in the lung tissue and enhanced protection of lung function. Furthermore, we found that UCMSCs secreted higher levels of anti-inflammatory cytokines (interleukin-10 and keratinocyte growth factor) in ALI-related conditions, which may be due to the greater therapeutic capacity of UCMSCs compared with MBMSCs. These findings suggest that MSCs protected the lipopolysaccharide-induced ALI model by regulating inflammation, most likely via paracrine factors. Moreover, MSCs derived from the UC may be a promising alternative for ALI treatment.

Mesenchymal stem cells: A double-edged sword in radiation-induced lung injury

Radiation therapy is an important treatment modality for multiple thoracic malignancies. However, radiation‐induced lung injury (RILI), which is the term generally used to describe damage to the lungs caused by exposure to ionizing radiation, remains a critical issue affecting both tumor control and patient quality of life. Despite tremendous effort, there is no current consensus regarding the optimal treatment approach for RILI. Because of a number of functional advantages, including self‐proliferation, multi‐differentiation, injury foci chemotaxis, anti‐inflammation, and immunomodulation, mesenchymal stem cells (MSCs) have been a focus of research for many years. Accumulating evidence indicates the therapeutic potential of transplantation of MSCs derived from adipose tissue, umbilical cord blood, and bone marrow for inflammatory diseases, including RILI. However, reports have also shown that MSCs, including fibrocytes, lung hematopoietic progenitor cells, and ABCG²⁺ MSCs, actually enhance the progression of lung injuries. These contradictory results suggest that MSCs may have dual effects and that caution should be taken when using MSCs to treat RILI. In this review, we present and discuss recent evidence of the double‐edged function of MSCs and provide comments on the prospects of these findings.