Potential application of mesenchymal stem cells in acute lung injury

Evaluating the therapeutic potential of different sources of mesenchymal stem cells in acute respiratory distress syndrome

BACKGROUND

Mesenchymal stem/stromal cells (MSCs) have attracted interest as a potential therapy given their anti-inflammatory and immunomodulatory properties. However, clinical trials using MSCs for acute respiratory distress syndrome (ARDS) have produced mixed and inconclusive data. In previous work, we performed a "head-to-head" comparison between different sources of MSCs and showed that each source had a unique genomic and proteomic "signature".

METHOD

This study investigated which sources of MSC: bone marrow derived-MSCs (BM-MSCs), adipose tissue derived-MSCs (AD-MSCs) and umbilical cord derived-MSCs (UC-MSCs)  would be the optimal candidate to be used as a therapy in an LPS-induced mouse model of ARDS. Immune cells assessment, tissue transcriptomics, animal survival, and endothelial-epithelial barrier assessment were used to evaluate their effects.

RESULTS

When comparing the three most commonly used MSC sources, we found that UC-MSCs exhibited greater efficacy compared to other MSCs in improving animal survival, mitigating epithelial/endothelial damage, decreasing lung inflammation via reducing neutrophil infiltration, T cell proliferation, and M1 polarization. Bulk RNA sequencing of lung tissue also showed that UC-MSCs have the capability to downregulate extracellular trap formation, by the downregulation of key genes like Elane and Padi4. Notably, treatment with UC-MSCs demonstrated a significant reduction in Fc-γ R mediated phagocytosis, which has been associated with monocyte pyroptosis and intense inflammation in the context of COVID-19.

CONCLUSION

Our findings suggest that UC-MSCs are an optimal source of MSC to treat acute inflammatory conditions in the lungs, such as ARDS.

Respiratory Patterns in Neurological Injury, Pathophysiology, Ventilation Management, and Future Innovations: A Systematic Review

Traumatic brain injuries (TBI), ischemic stroke, hemorrhagic stroke, brain tumors, and seizures have diverse and sometimes overlapping associated breathing patterns. Homeostatic mechanisms for respiratory control are intertwined with complex neurocircuitry, both centrally and peripherally. This paper summarizes the neurorespiratory control and pathophysiology of its disruption. It also reviews the clinical presentation, ventilatory management, and emerging therapeutics. This review additionally serves to update all recent preclinical and clinical research regarding the spectrum of respiratory dysfunction. Having a solid pathophysiological foundation of disruptive mechanisms would permit further therapeutic development. This novel review bridges experimental/physiological data with bedside management, thus allowing neurosurgeons and intensivists alike to rapidly diagnose and treat respiratory sequelae of acute brain injury.

Key Role of Mesenchymal Stromal Cell Interaction with Macrophages in Promoting Repair of Lung Injury

Lung macrophages (Mφs) are essential for pulmonary innate immunity and host defense due to their dynamic polarization and phenotype shifts. Mesenchymal stromal cells (MSCs) have secretory, immunomodulatory, and tissue-reparative properties and have shown promise in acute and chronic inflammatory lung diseases and in COVID-19. Many beneficial effects of MSCs are mediated through their interaction with resident alveolar and pulmonary interstitial Mφs. Bidirectional MSC-Mφ communication is achieved through direct contact, soluble factor secretion/activation, and organelle transfer. The lung microenvironment facilitates MSC secretion of factors that result in Mφ polarization towards an immunosuppressive M2-like phenotype for the restoration of tissue homeostasis. M2-like Mφ in turn can affect the MSC immune regulatory function in MSC engraftment and tissue reparatory effects. This review article highlights the mechanisms of crosstalk between MSCs and Mφs and the potential role of their interaction in lung repair in inflammatory lung diseases.

Clinical Translation of Engineered Pulmonary Vascular Models

Diseases in pulmonary vasculature remain a major cause of morbidity and mortality worldwide. Numerous pre-clinical animal models were developed to understand lung vasculature during diseases and development. However, these systems are typically limited in their ability to represent human pathophysiology for the study of disease and drug mechanisms. In recent years, a growing number of studies have focused on developing in vitro experimental platforms that mimic human tissues/organs. In this chapter, we discuss the key components involved in developing engineered pulmonary vascular modeling systems and provide perspectives on ways to improve the translational potential of existing models.

Mesenchymal stem cell-based therapy as a new therapeutic approach for acute inflammation

Acute inflammatory diseases such as acute colitis, kidney injury, liver failure, lung injury, myocardial infarction, pancreatitis, septic shock, and spinal cord injury are significant causes of death worldwide. Despite advances in the understanding of its pathophysiology, there are many restrictions in the treatment of these diseases, and new therapeutic approaches are required. Mesenchymal stem cell-based therapy due to immunomodulatory and regenerative properties is a promising candidate for acute inflammatory disease management. Based on preclinical results, mesenchymal stem cells and their-derived secretome improved immunological and clinical parameters. Furthermore, many clinical trials of acute kidney, liver, lung, myocardial, and spinal cord injury have yielded promising results. In this review, we try to provide a comprehensive view of mesenchymal stem cell-based therapy in acute inflammatory diseases as a new treatment approach.

TLR-activated mesenchymal stromal cell therapy and antibiotics to treat multi-drug resistant Staphylococcal septic arthritis in an equine model

BACKGROUND

Rapid development of antibiotic resistance necessitates advancement of novel therapeutic strategies to treat infection. Mesenchymal stromal cells (MSC) possess antimicrobial and immunomodulatory properties, mediated through antimicrobial peptide secretion and recruitment of innate immune cells including neutrophils and monocytes. TLR-3 activation of human, canine and equine MSC has been shown to enhance bacterial killing and clearance in vitro, in rodent Staphylococcal biofilm infection models and dogs with spontaneous multi-drug-resistant infections. The objective of this study was to determine if intra-articular (IA) TLR-3-activated MSC with antibiotics improved clinical parameters and reduced bacterial counts and inflammatory cytokine concentrations in synovial fluid (SF) of horses with induced septic arthritis.

METHODS

Eight horses were inoculated in one tarsocrural joint with multidrug-resistant Staphylococcus aureus (S. aureus). Bone marrow-derived MSC from three unrelated donors were activated with TLR-3 agonist polyinosinic, polycytidylic acid (pIC). Recipient horses received MSC plus vancomycin (TLR-MSC-VAN), or vancomycin (VAN) alone, on days 1, 4, 7 post-inoculation and systemic gentamicin. Pain scores, quantitative bacterial counts (SF, synovium), SF analyses, complete blood counts, cytokine concentrations (SF, plasma), imaging changes (MRI, ultrasound, radiographs), macroscopic joint scores and histologic changes were assessed. Results were reported as mean ± SEM.

RESULTS

Pain scores (d7, P=0.01, 15.2±0.2 vs. 17.9±0.5), ultrasound (d7, P=0.03, 9.0±0.6 vs. 11.8±0.5), quantitative bacterial counts (SF d7, P=0.02, 0±0 vs. 3.4±0.4; synovium P=0.003, 0.4±0.4 vs. 162.7±18.4), systemic neutrophil (d4, P=0.03, 4.6±0.6 vs. 7.8±0.6) and serum amyloid A (SAA) (d4, P=0.01, 1,106.0±659.0 vs. 2,858.8±141.3; d7, P=0.02, 761.8±746.2 vs. 2,357.3±304.3), and SF lactate (d7, P<0.0001, 5.4±0.2 vs. 15.0±0.3), SAA (endterm, P=0.01, 0.0 vs. 2,094.0±601.6), IL-6 (P=0.03, 313.0±119.2 vs. 1,328.2±208.9), and IL-18 (P=0.02, 11.1±0.5 vs. 13.3±3.8) were improved in TLR-MSC-VAN vs. VAN horses. Study limitations include the small horse sample size, short study duration, and lack of additional control groups.

CONCLUSIONS

Combined TLR-activated MSC with antibiotic therapy may be a promising approach to manage joint infections with drug resistant bacteria.

Biomaterials for Tissue Engineering Applications and Current Updates in the Field: A Comprehensive Review

Tissue engineering has emerged as an interesting field nowadays; it focuses on accelerating the auto-healing mechanism of tissues rather than organ transplantation. It involves implanting an In Vitro cultured initiative tissue or a scaffold loaded with tissue regenerating ingredients at the damaged area. Both techniques are based on the use of biodegradable, biocompatible polymers as scaffolding materials which are either derived from natural (e.g. alginates, celluloses, and zein) or synthetic sources (e.g. PLGA, PCL, and PLA). This review discusses in detail the recent applications of different biomaterials in tissue engineering highlighting the targeted tissues besides the in vitro and in vivo key findings. As well, smart biomaterials (e.g. chitosan) are fascinating candidates in the field as they are capable of elucidating a chemical or physical transformation as response to external stimuli (e.g. temperature, pH, magnetic or electric fields). Recent trends in tissue engineering are summarized in this review highlighting the use of stem cells, 3D printing techniques, and the most recent 4D printing approach which relies on the use of smart biomaterials to produce a dynamic scaffold resembling the natural tissue. Furthermore, the application of advanced tissue engineering techniques provides hope for the researchers to recognize COVID-19/host interaction, also, it presents a promising solution to rejuvenate the destroyed lung tissues.

Stem cells, cell therapies, and bioengineering in lung biology and disease 2021

The 9th biennial conference titled "Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases" was hosted virtually, due to the ongoing COVID-19 pandemic, in collaboration with the University of Vermont Larner College of Medicine, the National Heart, Lung, and Blood Institute, the Alpha-1 Foundation, the Cystic Fibrosis Foundation, and the International Society for Cell & Gene Therapy. The event was held from July 12th through 15th, 2021 with a pre-conference workshop held on July 9th. As in previous years, the objectives remained to review and discuss the status of active research areas involving stem cells (SCs), cellular therapeutics, and bioengineering as they relate to the human lung. Topics included 1) technological advancements in the in situ analysis of lung tissues, 2) new insights into stem cell signaling and plasticity in lung remodeling and regeneration, 3) the impact of extracellular matrix in stem cell regulation and airway engineering in lung regeneration, 4) differentiating and delivering stem cell therapeutics to the lung, 5) regeneration in response to viral infection, and 6) ethical development of cell-based treatments for lung diseases. This selection of topics represents some of the most dynamic and current research areas in lung biology. The virtual workshop included active discussion on state-of-the-art methods relating to the core features of the 2021 conference, including in situ proteomics, lung-on-chip, induced pluripotent stem cell (iPSC)-airway differentiation, and light sheet microscopy. The conference concluded with an open discussion to suggest funding priorities and recommendations for future research directions in basic and translational lung biology.

Phase 1 clinical trial for intravenous administration of mesenchymal stem cells derived from umbilical cord and placenta in patients with moderate COVID-19 virus pneumonia: results of stage 1 of the study

OBJECTIVE

Mesenchymal stem cells can serve as a therapeutic option for COVID-19. Their immunomodulatory and anti-inflammatory properties can regulate the exaggerated inflammatory response and promote recovery of lung damage.

METHOD

Phase-1, single-centre open-label, prospective clinical trial was conducted to evaluate the safety and efficacy of intravenous administration of mesenchymal stem cells derived from umbilical cord and placenta in moderate COVID-19. The study was done in 2 stages with total 20 patients. Herein, the results of stage 1 including first 10 patients receiving 100 million cells on day 1 and 4 with a follow up of 6 months have been discussed.

RESULTS

No adverse events were recorded immediately after the administration of MSCs or on follow up. There was no deterioration observed in clinical, laboratory and radiological parameters. All symptoms of the study group resolved within 10 days. Levels of inflammatory biomarkers such as NLR, CRP, IL6, ferritin and D-dimer improved in all patients after intervention along with improved oxygenation demonstrated by improvement in the SpO2/FiO2 ratio and PaO2/FiO2 ratio. None of the patients progressed to severe stage. 9 out of 10 patients were discharged within 9 days of their admission. Improvements were noted in chest x-ray and chest CT scan scores at day 7 in most patients. No post-covid fibrosis was observed on chest CT 28 days after intervention and Chest X ray after 6 months of the intervention.

CONCLUSION

Administration of 100 million mesenchymal stem cells in combination with standard treatment was found to be safe and resulted in prevention of the cytokine storm, halting of the disease progression and acceleration of recovery in moderate COVID-19. This clinical trial has been registered with the Clinical Trial Registry- India (CTRI) as CTRI/2020/08/027043. http://www.ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=43175.

The anti-inflammatory feature of glucagon-like peptide-1 and its based diabetes drugs—Therapeutic potential exploration in lung injury

Since 2005, GLP-1 receptor (GLP-1R) agonists (GLP-1RAs) have been developed as therapeutic agents for type 2 diabetes (T2D). GLP-1R is not only expressed in pancreatic islets but also other organs, especially the lung. However, controversy on extra-pancreatic GLP-1R expression still needs to be further resolved, utilizing different tools including the use of more reliable GLP-1R antibodies in immune-staining and co-immune-staining. Extra-pancreatic expression of GLP-1R has triggered extensive investigations on extra-pancreatic functions of GLP-1RAs, aiming to repurpose them into therapeutic agents for other disorders. Extensive studies have demonstrated promising anti-inflammatory features of GLP-1RAs. Whether those features are directly mediated by GLP-1R expressed in immune cells also remains controversial. Following a brief review on GLP-1 as an incretin hormone and the development of GLP-1RAs as therapeutic agents for T2D, we have summarized our current understanding of the anti-inflammatory features of GLP-1RAs and commented on the controversy on extra-pancreatic GLP-1R expression. The main part of this review is a literature discussion on GLP-1RA utilization in animal models with chronic airway diseases and acute lung injuries, including studies on the combined use of mesenchymal stem cell (MSC) based therapy. This is followed by a brief summary.

Stem Cell-based therapies for COVID-19-related acute respiratory distress syndrome

As the number of confirmed cases and resulting death toll of the COVID-19 pandemic continue to increase around the globe - especially with the emergence of new mutations of the SARS-CoV-2 virus in addition to the known alpha, beta, gamma, delta and omicron variants - tremendous efforts continue to be dedicated to the development of interventive therapeutics to mitigate infective symptoms or post-viral sequelae in individuals for which vaccines are not accessible, viable or effective in the prevention of illness. Many of these investigations aim to target the associated acute respiratory distress syndrome, or ARDS, which induces damage to lung epithelia and other physiologic systems and is associated with progression in severe cases. Recently, stem cell-based therapies have demonstrated preliminary efficacy against ARDS based on a number of preclinical and preliminary human safety studies, and based on promising outcomes are now being evaluated in phase II clinical trials for ARDS. A number of candidate stem cell therapies have been found to exhibit low immunogenicity, coupled with inherent tropism to injury sites. In recent studies, these have demonstrated the ability to modulate suppression of pro-inflammatory cytokine signals such as those characterizing COVID-19-associated ARDS. Present translational studies are aiming to optimize the safety, efficacy and delivery to fully validate stem cell-based strategies targeting COVID-19 associated ARDS for viable clinical application.

The critical role of mesenchymal stromal/stem cell therapy in COVID-19 patients: An updated review

New coronavirus disease 2019 (COVID-19), as a pandemic disaster, has drawn the attention of researchers in various fields to discover suitable therapeutic approaches for the management of COVID-19 patients. Currently, there are many worries about the rapid spread of COVID-19; there is no approved treatment for this infectious disease, despite many efforts to develop therapeutic procedures for COVID-19. Emerging evidence shows that mesenchymal stromal/stem cell (MSC) therapy can be a suitable option for the management of COVID-19. These cells have many biological features (including the potential of differentiation, high safety and effectiveness, secretion of trophic factors and immunoregulatory features) that make them suitable for the treatment of various diseases. However, some studies have questioned the positive role of MSC therapy in the treatment of COVID-19. Accordingly, in this paper, we will focus on the therapeutic impacts of MSCs and their critical role in cytokine storm of COVID-19 patients.

Heterogeneous expression of ACE2 and TMPRRS2 in mesenchymal stromal cells

The outbreak of COVID‐19 has become a serious public health emergency. The virus targets cells by binding the ACE2 receptor. After infection, the virus triggers in some humans an immune storm containing the release of proinflammatory cytokines and chemokines followed by multiple organ failure. Several vaccines are enrolled, but an effective treatment is still missing. Mesenchymal stem cells (MSCs) have shown to secrete immunomodulatory factors that suppress this cytokine storm. Therefore, MSCs have been suggested as a potential treatment option for COVID‐19. We report here that the ACE2 expression is minimal or nonexistent in MSC derived from three different human tissue sources (adipose tissue, umbilical cord Wharton`s jelly and bone marrow). In contrast, TMPRSS2 that is implicated in SARS‐CoV‐2 entry has been detected in all MSC samples. These results are of particular importance for future MSC‐based cell therapies to treat severe cases after COVID‐19 infection.

Protective effect of conditioned media of human fetal dermal mesenchymal stem cells can inhibit burn-induced microvascular hyperpermeability

Burns often cause loss of skin barrier protection, fluid exudation, and local tissue edema, which hinder functional recovery. Effectively improving the quality of deep burn wound healing, shortening the wound healing time, and reducing tissue fluid leakage are urgent problems in the medical field. Human mesenchymal stem cells (MSCs) can effectively stabilize vascular endothelial injury. Fetal dermal MSCs (FDMSCs) are a newly discovered source of MSCs derived from the skin of accidentally aborted fetuses. However, the effect of FDMSCs on vascular permeability remains poorly understood. In this study, conditioned media from FDMSCs (F-CM) extracted from fetal skin tissue was prepared. The effect of F-CM on vascular permeability was evaluated using the internal circulation method FITC-dextran in vivo, and several in vitro assays, including cell viability assay, transwell permeability test, immunofluorescence, and western blotting. Altogether, our results demonstrate that F-CM could inhibit burn-induced microvascular hyperpermeability by increasing the protein expression levels of occludin and VE-cadherin, while restoring the expression of endothelial F-actin, and providing the foundation of a novel therapy for the treatment of burns with F-CM.

Stem cell-based and mesenchymal stem cell derivatives for coronavirus treatment

Coronavirus disease 2019 (COVID-19) as one of the types of pneumonia was first reported in Wuhan, China in December 2019. COVID-19 is considered the third most common coronavirus among individuals after acute respiratory syndrome (SARS-CoV) and the Middle East respiratory syndrome (MERS-CoV) in the 20th century. Many studies have shown that cell therapy and regenerative medicine approaches have an impressive effect on different dangerous diseases in a way that using a cell-based experiment could be effective for improving humans with severe acute respiratory infections caused by the 2019 novel coronavirus. Accordingly, due to the stunning effects of mesenchymal stem cells (MSCs) and derivatives on the treatment of various diseases, this review focuses on the auxiliary role of MSCs and their derivatives in reducing the inflammatory processes of acute respiratory infections resulted from the 2019 novel coronavirus. The reported MSCs treatment outcomes are significant because these cells prevent the immune system from overactivating and improve, endogenous repair by improving the lung microenvironment after the SARS-CoV-2 infection. The MSCs can be an effective, autologous, and safe treatment, and therefore, share the results. To date, the results of several studies have shown that MSCs and their derivatives can inhibit inflammation. Exosomes act as intercellular communication devices between cells for the transfer of active molecules. In this review, recent MSCs and their derivatives-based clinical trials for the cure of COVID-19 are introduced.

FGF/FGFR signaling: From lung development to respiratory diseases

The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling system regulates a variety of biological processes, including embryogenesis, angiogenesis, wound repair, tissue homeostasis, and cancer. It exerts these regulatory functions by controlling proliferation, differentiation, migration, survival, and metabolism of target cells. The morphological structure of the lung is a complex tree-like network for effective oxygen exchange, and the airway terminates in the middle and distal ends of many alveoli. FGF/FGFR signaling plays an important role in the pathophysiology of lung development and pathogenesis of various human respiratory diseases. Here, we mainly review recent advances in FGF/FGFR signaling during human lung development and respiratory diseases, including lung cancer, acute lung injury (ALI), pulmonary arterial hypertension (PAH), chronic obstructive pulmonary disease (COPD), asthma, and pulmonary fibrosis.

COVID-19 and the role of stem cells

There is currently an ongoing coronavirus respiratory disease (COVID-19) pandemic that is caused by SARS-CoV-2 virus, which emerged out of Wuhan, China. In severe cases, the disease can progress to respiratory distress, hypoxia, and multi-organ failure, all of which are associated with high mortality. Mesenchymal stem cells (MSCs) possess potent and broad-ranging immunomodulatory activities. MSCs have demonstrated their impressive ability to inhibit lung damage, reduce inflammation, attenuate the immune response, and aid with alveolar fluid clearance. Studies that investigated the use of MSCs and exosome cells derived from MSCs in treating COVD-19 patients have encouraging results. The conclusion of the results of four clinical studies, as presented in this review article, is reduced patient mortality in more than half of the subjects who were administered MSCs or exosomes derived from MSCs, intravenously, positioning these cells as a possible therapeutic solution for COVID-19. While the studies do have limitations, they do provide a stepping stone based on different approaches in the search for treatment to save patients.

Mesenchymal Stem Cell-Based Therapy as an Alternative to the Treatment of Acute Respiratory Distress Syndrome: Current Evidence and Future Perspectives

Acute respiratory distress syndrome (ARDS) represents a current challenge for medicine due to its incidence, morbidity and mortality and, also, the absence of an optimal treatment. The COVID-19 outbreak only increased the urgent demand for an affordable, safe and effective treatment for this process. Early clinical trials suggest the therapeutic usefulness of mesenchymal stem cells (MSCs) in acute lung injury (ALI) and ARDS. MSC-based therapies show antimicrobial, anti-inflammatory, regenerative, angiogenic, antifibrotic, anti-oxidative stress and anti-apoptotic actions, which can thwart the physiopathological mechanisms engaged in ARDS. In addition, MSC secretome and their derived products, especially exosomes, may reproduce the therapeutic effects of MSC in lung injury. This last strategy of treatment could avoid several safety issues potentially associated with the transplantation of living and proliferative cell populations and may be formulated in different forms. However, the following diverse limitations must be addressed: (i) selection of the optimal MSC, bearing in mind both the heterogeneity among donors and across different histological origins, (ii) massive obtention of these biological products through genetic manipulations of the most appropriate MSC, (iii) bioreactors that allow their growth in 3D, (iv) ideal culture conditions and (v) adequate functional testing of these obtaining biological products before their clinical application.

Case Report: Human Umbilical Cord Mesenchymal Stem Cells as a Therapeutic Intervention for a Critically Ill COVID-19 Patient

Here we report a critically ill patient who was cured of SARS-CoV-2 infection in Changsha, China. A 66-year-old Chinese woman, with no significant past medical history, developed severe pneumonia-like symptoms and later diagnosed as severe COVID-19 pneumonia. Within 2 months of hospitalization, the patient deteriorated to ARDS including pulmonary edema and SIRS with septic shock. When treatment schemes such as antibiotics plus corticosteroids showed diminished therapeutic value, hUCMSC therapy was compassionately prescribed under the patient's consent of participation. After treatment, there was significant improvement in disease inflammation-related indicators such as IL-4, IL-6, and IL-10. Eventually, it confirmed the therapeutic value that hUCMSCs could dampen the cytokine storm in the critically ill COVID-19 patient and modulated the NK cells. In the continued hUCMSC treatment, gratifying results were achieved in the follow-up of the patient. The data we acquired anticipate a significant therapeutic value of MSC treatment in severe and critically ill patients with COVID-19, while further studies are needed.

New perspective towards therapeutic regimen against SARS-CoV-2 infection

The ongoing enormous loss of human life owing to Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), has led to a global crisis ranging from the collapse of health - care systems to socio-economic instability. As SARS-CoV-2 is a novel virus, very little information is available from researchers and therefore, a rigorous effort is required to decode its pathogenicity. There are no licenced treatment options available for treating SARS-CoV-2 infections and the development of a new antiviral drug targeting coronavirus cannot happen soon. Consequently, drug repurposing is a promising solution for combating the present pandemic. In this review, we have thoroughly discussed all the proteins encoded by the SARS-CoV-2 genome; their importance in pathogenicity and their potential role in drug discovery. Also, the budding threat of co-infections by other pathogenic microbes has been highlighted. Furthermore, the advances made in the medicinal field for the treatment and prevention of this viral infection is explained. Altogether, this review will provide some insightful discussions about this infectious disease and will meet certain of the knowledge gaps which exist by presenting an exhaustive and extensive scientific report on the ongoing mission for COVID-19 drug discovery.

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

Background

One of the characteristics of acute lung injury (ALI) is severe pulmonary edema, which is closely related to alveolar fluid clearance (AFC). Mesenchymal stem cells (MSCs) secrete a wide range of cytokines, growth factors, and microRNA (miRNAs) through paracrine action to participate in the mechanism of pulmonary inflammatory response, which increase the clearance of edema fluid and promote the repair process of ALI. The epithelial sodium channel (ENaC) is the rate-limiting step in the sodium–water transport and edema clearance in the alveolar cavity; the role of bone marrow-derived MSC-conditioned medium (BMSC-CM) in edema clearance and how miRNAs affect ENaC are still seldom known.

Methods

CCK-8 cell proliferation assay was used to detect the effect of BMSC-CM on the survival of alveolar type 2 epithelial (AT2) cells. Real-time polymerase chain reaction (RT-PCR) and western blot were used to detect the expression of ENaC in AT2 cells. The effects of miR-34c on lung fluid absorption were observed in LPS-treated mice in vivo, and the transepithelial short-circuit currents in the monolayer of H441 cells were examined by the Ussing chamber setup. Dual luciferase reporter gene assay was used to detect the target gene of miR-34c.

Results

BMSC-CM could increase the viability of mouse AT2 cells. RT-PCR and western blot results showed that BMSC-CM significantly increased the expression of the γ-ENaC subunit in mouse AT2 cells. MiR-34c could restore the AFC and lung wet/dry weight ratio in the ALI animal model, and Ussing chamber assay revealed that miR-34c enhanced the amiloride-sensitive currents associated with ENaC activity in intact H441 cell monolayers. In addition, we observed a higher expression of miR-34c in mouse AT2 cells administrated with BMSC-CM, and the overexpression or inhibition of miR-34c could regulate the expression of ENaC protein and alter the function of ENaC. Finally, we detected that myristoylated alanine-rich C kinase substrate (MARCKS) may be one of the target genes of miR-34c.

Conclusion

Our results indicate that BMSC-CM may alleviate LPS-induced ALI through miR-34c targeting MARCKS and regulate ENaC indirectly, which further explores the benefit of paracrine effects of bone marrow-derived MSCs on edematous ALI.

Exosomes contribution in COVID-19 patients' treatment

Adipose cell-free derivatives have been recently gaining attention as potential therapeutic agents for various human diseases. In this context, mesenchymal stromal/stem cells (MSCs), adipocyte mesenchymal stem cells (Ad-MSCs) and adipose-derived stem cells (ADSC) possessing potent immunomodulatory activities are proposed as a therapeutic option for the treatment of coronavirus disease 2019 (COVID-19). The COVID-19 represents a global concern of public health caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in which there is not actually any specific therapy. MSCs exert an immunomodulation effect due to the secretion of endogenous factors, such as vascular endothelial growth factor (VEGF), insulin growth factor (IGF), and nerve growth factor (NGF), transforming growth factor (TGF)-β and growth differentiation factor (GDF)-11. Recent reports are promising for further studies and clinical applications of ADSCs and Ad-MSCs in COVID-19 patients. Experimental and clinical studies are exploring the therapeutic potential of both MSCs and derived-exosomes in moderating the morbidity and mortality of COVID-19. In this field, more preclinical and clinical studies are warranted to find an effective treatment for the patients suffering from COVID-19 infection.

Therapeutic approaches to coronavirus infection according to "One Health" concept

Coronaviridae constantly infect human and animals causing respiratory, gastroenteric or systemic diseases. Over time, these viruses have shown a marked ability to mutate, jumping over the human-animal barrier, thus becoming from enzootic to zoonotic. In the last years, numerous therapeutic protocols have been developed, mainly for severe acute respiratory syndromes in humans. The aim of this review is to summarize drugs or other approaches used in coronavirus infections focusing on different roles of these molecules or bacterial products on viral adhesion and replication or in modulating the host's immune system. Within the "One Health" concept, the study of viral pathogenic role and possible therapeutic approaches in both humans and animals is essential to protect public health.

Impact of Three Different Serum Sources on Functional Properties of Equine Mesenchymal Stromal Cells

Culture and expansion of equine mesenchymal stromal cells (MSCs) are routinely performed using fetal bovine serum (FBS) as a source of growth factors, nutrients, and extracellular matrix proteins. However, the desire to minimize introduction of xenogeneic bovine proteins or pathogens and to standardize cellular products intended for clinical application has driven evaluation of alternatives to FBS. Replacement of FBS in culture for several days before administration has been proposed to reduce antigenicity and potentially prolong survival after injection. However, the functional consequences of MSC culture in different serum types have not been fully evaluated. The objective of this study was to compare the immunomodulatory and antibacterial properties of MSCs cultured in three serum sources: FBS or autologous or allogeneic equine serum. We hypothesized that continuous culture in FBS would generate MSCs with improved functionality compared to equine serum and that there would not be important differences between MSCs cultured in autologous vs. allogeneic equine serum. To address these questions, MSCs from three healthy donor horses were expanded in medium with FBS and then switched to culture in FBS or autologous or allogeneic equine serum for 72 h. The impact of this 72-h culture period in different sera on cell viability, cell doubling time, cell morphology, bactericidal capability, chondrogenic differentiation, and production of cytokines and antimicrobial peptides was assessed. Altering serum source did not affect cell viability or morphology. However, cells cultured in FBS had shorter cell doubling times and secreted more interleukin 4 (IL-4), IL-5, IL-17, RANTES, granulocyte–macrophage colony-stimulating factor, fibroblast growth factor 2, eotaxin, and antimicrobial peptide cathelicidin/LL-37 than cells cultured in either source of equine serum. Cells cultured in FBS also exhibited greater spontaneous bactericidal activity. Notably, significant differences in any of these parameters were not observed when autologous vs. allogeneic equine serum was used for cell culture. Chondrogenic differentiation was not different between different serum sources. These results indicate that MSC culture in FBS will generate more functional cells based on a number of parameters and that the theoretical risks of FBS use in MSC culture should be weighed against the loss of MSC function likely to be incurred from culture in equine serum.

Toll-like receptor activation of equine mesenchymal stromal cells to enhance antibacterial activity and immunomodulatory cytokine secretion

OBJECTIVE

To evaluate effects of Toll-like and nucleotide-binding oligomerization domain (NOD)-like receptor (TLR, NLR) ligand stimulation of equine mesenchymal stromal cells (MSCs) on antibacterial and immunomodulatory properties in vitro.

STUDY DESIGN

Controlled laboratory study.

SAMPLE POPULATION

Equine bone-marrow-derived MSCs (three horses).

METHODS

MSCs were stimulated with TLR (polyinosinic:polycytidylic acid [pIC] and lipopolysaccharide [LPS]) and NLR agonists (γ-d-Glu-mDAP [IE-DAP]) for 2 h, and plated at 1 × 10⁵ cells/well 24 h. MSC-conditioned media (MSC-CM) were collected and assessed for antimicrobial peptide cathelicidin/LL-37 production, bactericidal action against multidrug-resistant planktonic and biofilm Staphylococcus aureus and neutrophil phagocytosis. Bacterial growth was measured by plating bacteria and counting viable colonies, reading culture absorbance, and live-dead staining with confocal microscopy imaging. Following initial comparison of activating stimuli, TLR3-agonist pIC protocols (cell density during activation and plating, culture time, %serum) were further optimized for bactericidal activity and secretion of interleukin-8 (IL-8), monocyte-chemoattractant-protein (MCP-1), and cathelicidin/LL37.

RESULTS

MSCs stimulation with pIC (p = .004) and IE-DAP (p = .03) promoted increased bactericidal activity, evidenced by reduced viable planktonic colony counts. PIC stimulation (2 × 10⁶ cells/ml, 2 h, 10 μg/ml) further suppressed biofilm formation (p = .001), enhanced neutrophil bacterial phagocytosis (p = .009), increased MCP-1 secretion (p < .0001), and enhanced cathelicidin/LL-37 production, which was apparent when serum concentration in media was reduced to 1% (p = .01) and 2.5% (p = .05).

CONCLUSION

TLR-3 pIC MSCs activation was most effective to enhance antibacterial and cytokine responses, which were affected by serum reduction.

CLINICAL SIGNIFICANCE

In vitro TLR-3 activation of equine MSCs tested here may be a strategy to improve antibacterial properties of MSCs to treat antibiotic-resistant infections.

Mesenchymal Stem Cells as a Cornerstone in a Galaxy of Intercellular Signals: Basis for a New Era of Medicine

Around 40% of the population will suffer at some point in their life a disease involving tissue loss or an inflammatory or autoimmune process that cannot be satisfactorily controlled with current therapies. An alternative for these processes is represented by stem cells and, especially, mesenchymal stem cells (MSC). Numerous preclinical studies have shown MSC to have therapeutic effects in different clinical conditions, probably due to their mesodermal origin. Thereby, MSC appear to play a central role in the control of a galaxy of intercellular signals of anti-inflammatory, regenerative, angiogenic, anti-fibrotic, anti-oxidative stress effects of anti-apoptotic, anti-tumor, or anti-microbial type. This concept forces us to return to the origin of natural physiological processes as a starting point to understand the evolution of MSC therapy in the field of regenerative medicine. These biological effects, demonstrated in countless preclinical studies, justify their first clinical applications, and draw a horizon of new therapeutic strategies. However, several limitations of MSC as cell therapy are recognized, such as safety issues, handling difficulties for therapeutic purposes, and high economic cost. For these reasons, there is an ongoing tendency to consider the use of MSC-derived secretome products as a therapeutic tool, since they reproduce the effects of their parent cells. However, it will be necessary to resolve key aspects, such as the choice of the ideal type of MSC according to their origin for each therapeutic indication and the implementation of new standardized production strategies. Therefore, stem cell science based on an intelligently designed production of MSC and or their derivative products will be able to advance towards an innovative and more personalized medical biotechnology.

Strategies to Potentiate Paracrine Therapeutic Efficacy of Mesenchymal Stem Cells in Inflammatory Diseases

Mesenchymal stem cells (MSCs) have been developed as cell therapeutics for various immune disorders using their immunoregulatory properties mainly exerted by their paracrine functions. However, variation among cells from different donors, as well as rapid clearance after transplantation have impaired the uniform efficacy of MSCs and limited their application. Recently, several strategies to overcome this limitation have been suggested and proven in pre-clinical settings. Therefore, in this review article, we will update the knowledge on bioengineering strategies to improve the immunomodulatory functions of MSCs, including genetic modification and physical engineering.

Stem cells and COVID-19: are the human amniotic cells a new hope for therapies against the SARS-CoV-2 virus?

A new coronavirus respiratory disease (COVID-19) caused by the SARS-CoV-2 virus, surprised the entire world, producing social, economic, and health problems. The COVID-19 triggers a lung infection with a multiple proinflammatory cytokine storm in severe patients. Without effective and safe treatments, COVID-19 has killed thousands of people, becoming a pandemic. Stem cells have been suggested as a therapy for lung-related diseases. In particular, mesenchymal stem cells (MSCs) have been successfully tested in some clinical trials in patients with COVID-19. The encouraging results positioned MSCs as a possible cell therapy for COVID-19. The amniotic membrane from the human placenta at term is a valuable stem cell source, including human amniotic epithelial cells (hAECs) and human mesenchymal stromal cells (hAMSCs). Interestingly, amnion cells have immunoregulatory, regenerative, and anti-inflammatory properties. Moreover, hAECs and hAMSCs have been used both in preclinical studies and in clinical trials against respiratory diseases. They have reduced the inflammatory response and restored the pulmonary tissue architecture in lung injury in vivo models. Here, we review the existing data about the stem cells use for COVID-19 treatment, including the ongoing clinical trials. We also consider the non-cellular therapies that are being applied. Finally, we discuss the human amniotic membrane cells use in patients who suffer from immune/inflammatory lung diseases and hypothesize their possible use as a successful treatment against COVID-19.

A Scoping Insight on Potential Prophylactics, Vaccines and Therapeutic Weaponry for the Ongoing Novel Coronavirus (COVID-19) Pandemic- A Comprehensive Review

The emergence of highly virulent CoVs (SARS-CoV-2), the etiologic agent of novel ongoing "COVID-19" pandemics has been marked as an alarming case of pneumonia posing a large global healthcare crisis of unprecedented magnitude. Currently, the COVID-19 outbreak has fueled an international demand in the biomedical field for the mitigation of the fast-spreading illness, all through the urgent deployment of safe, effective, and rational therapeutic strategies along with epidemiological control. Confronted with such contagious respiratory distress, the global population has taken significant steps towards a more robust strategy of containment and quarantine to halt the total number of positive cases but such a strategy can only delay the spread. A substantial number of potential vaccine candidates are undergoing multiple clinical trials to combat COVID-19 disease, includes live-attenuated, inactivated, viral-vectored based, sub-unit vaccines, DNA, mRNA, peptide, adjuvant, plant, and nanoparticle-based vaccines. However, there are no licensed anti-COVID-19 drugs/therapies or vaccines that have proven to work as more effective therapeutic candidates in open-label clinical trial studies. To counteract the infection (SARS-CoV-2), many people are under prolonged treatment of many chemical drugs that inhibit the PLpro activity (Ribavirin), viral proteases (Lopinavir/Ritonavir), RdRp activity (Favipiravir, Remdesivir), viral membrane fusion (Umifenovir, Chloroquine phosphate (CQ), Hydroxychloroquine phosphate (HCQ), IL-6 overexpression (Tocilizumab, Siltuximab, Sarilumab). Mesenchymal Stem Cell therapy and Convalescent Plasma Therapy have emerged as a promising therapeutic strategy against SARS-CoV-2 virion. On the other hand, repurposing previously designed antiviral agents with tolerable safety profile and efficacy could be the only promising approach and fast response to the novel virion. In addition, research institutions and corporations have commenced the redesign of the available therapeutic strategy to manage the global crisis. Herein, we present succinct information on selected anti-COVID-19 therapeutic medications repurposed to combat SARS-CoV-2 infection. Finally, this review will provide exhaustive detail on recent prophylactic strategies and ongoing clinical trials to curb this deadly pandemic, outlining the major therapeutic areas for researchers to step in.

Application of Nanotechnology in the COVID-19 Pandemic

COVID-19, caused by SARS-CoV-2 infection, has been prevalent worldwide for almost a year. In early 2000, there was an outbreak of SARS-CoV, and in early 2010, a similar dissemination of infection by MERS-CoV occurred. However, no clear explanation for the spread of SARS-CoV-2 and a massive increase in the number of infections has yet been proposed. The best solution to overcome this pandemic is the development of suitable and effective vaccines and therapeutics. Fortunately, for SARS-CoV-2, the genome sequence and protein structure have been published in a short period, making research and development for prevention and treatment relatively easy. In addition, intranasal drug delivery has proven to be an effective method of administration for treating viral lung diseases. In recent years, nanotechnology-based drug delivery systems have been applied to intranasal drug delivery to overcome various limitations that occur during mucosal administration, and advances have been made to the stage where effective drug delivery is possible. This review describes the accumulated knowledge of the previous SARS-CoV and MERS-CoV infections and aims to help understand the newly emerged SARS-CoV-2 infection. Furthermore, it elucidates the achievements in developing COVID-19 vaccines and therapeutics to date through existing approaches. Finally, the applicable nanotechnology approach is described in detail, and vaccines and therapeutic drugs developed based on nanomedicine, which are currently undergoing clinical trials, have presented the potential to become innovative alternatives for overcoming COVID-19.

Mesenchymal Stem Cell-Conditioned Medium Rescues LPS-Impaired ENaC Activity in Mouse Trachea via WNK4 Pathway

BACKGROUND

Airway epithelium plays an essential role in maintaining the homeostasis and function of respiratory system as the first line of host defense. Of note, epithelial sodium channel (ENaC) is one of the victims of LPS-induced airway injury. Regarding the great promise held by mesenchymal stem cells (MSCs) for regenerative medicine in the field of airway injury and the limitations of cell-based MSCs therapy, we focused on the therapeutic effect of MSCs conditioned medium (MSCs-CM) on the ENaC activity in mouse tracheal epithelial cells.

METHODS

Ussing chamber apparatus was applied to record the short-circuit currents in primary cultured mouse tracheal epithelial cells, which reflects the ENaC activity. Expressions of α and γ ENaC were measured at the protein and mRNA levels by western blot and real-time PCR, respectively. The expression of with-no-lysinekinase- 4 (WNK4) and ERK1/2 were measured at protein levels, and the relationship between WNK4 and ERK1/2 was determined by WNK4 knockdown.

RESULTS

MSCs-CM restored the LPS-impaired ENaC activity, as well as enhanced the mRNA and protein expressions of ENaC in primary cultured mouse tracheal epithelial cells. Meanwhile, WNK4 and ERK1/2, both negative-regulators of ENaC, were suppressed accordingly after the administration of MSCs-CM in LPS-induced airway injury. After WNK4 gene was knocked down by siRNA, the level of ERK1/2 phosphorylation decreased.

CONCLUSION

In light of the key role of ENaC in fluid reabsorption and the beneficial effects of MSCs-CM in the injury of airway epithelium, our results suggest that MSCs-CM is effective in alleviating LPS-induced ENaC dysfunction through WNK4-ERK1/2 pathway, which will provide a potent direction for the therapy of airway injury.

Current Status and Future Prospects of Perinatal Stem Cells

The placenta is a temporary organ that is discarded after birth and is one of the most promising sources of various cells and tissues for use in regenerative medicine and tissue engineering, both in experimental and clinical settings. The placenta has unique, intrinsic features because it plays many roles during gestation: it is formed by cells from two individuals (mother and fetus), contributes to the development and growth of an allogeneic fetus, and has two independent and interacting circulatory systems. Different stem and progenitor cell types can be isolated from the different perinatal tissues making them particularly interesting candidates for use in cell therapy and regenerative medicine. The primary source of perinatal stem cells is cord blood. Cord blood has been a well-known source of hematopoietic stem/progenitor cells since 1974. Biobanked cord blood has been used to treat different hematological and immunological disorders for over 30 years. Other perinatal tissues that are routinely discarded as medical waste contain non-hematopoietic cells with potential therapeutic value. Indeed, in advanced perinatal cell therapy trials, mesenchymal stromal cells are the most commonly used. Here, we review one by one the different perinatal tissues and the different perinatal stem cells isolated with their phenotypical characteristics and the preclinical uses of these cells in numerous pathologies. An overview of clinical applications of perinatal derived cells is also described with special emphasis on the clinical trials being carried out to treat COVID19 pneumonia. Furthermore, we describe the use of new technologies in the field of perinatal stem cells and the future directions and challenges of this fascinating and rapidly progressing field of perinatal cells and regenerative medicine.

Drug Repurposing for Prevention and Treatment of COVID-19: A Clinical Landscape

SARS-CoV-2, the novel coronavirus strain responsible for the current pandemic of COVID-19, has rendered the entire humanity suffering. Several months have passed since the pandemic has struck. However, the world is still looking for an effective treatment plan to battle the viral infection. The first vaccine just received emergency approval in December 2020 for use in USA and UK. These are excellent news, however, the worldwide distribution of such vaccine, the possibility of virus mutation and the lack of data regarding the long-term effects of such vaccines are a significant concern. In addition, although remdesivir was recently approved by the FDA to be used as a clinical drug against COVID-19, it hasn't stood out yet as a proven form of therapeutics. Such inability to produce a novel therapy has caused enough inconveniences for the affected people worldwide. Repurposing the already available drugs to fight against the virus seems to be a reasonable option amidst such uncertainty. Given the vast collection of potential treatment candidates to be explored against COVID-19, there is a decent chance that a success in this regard will serve the intermediary purpose of clinically treating the infection until a COVID-19 vaccine is widely distributed worldwide and will be able to treat COVID-19 patients that do not adequately respond to vaccines. Such treatments may prove very useful in future coronavirus outbreaks too. Proper research into these repurposing treatments may yield a certain insight into the field of novel treatment production as well. This review study accumulates a relevant set of information about drugs and vaccines against COVID-19, in terms of their repurposing properties and the specific phases of clinical trials they are undergoing across the world.  A potential timeline is also suggested to estimate when an effective result can be expected from the ongoing clinical trials for a better anticipation of the drug landscape. This study will hopefully help accelerate investment of resources into development and discovery of drugs and vaccines against the infection.

Mesenchymal stem cell therapies for COVID-19: Current status and mechanism of action

The outbreak of COVID-19 in December 2019, has become an urgent and serious public health emergency. At present, there is no effective treatment or vaccine for COVID-19. Therefore, there is a crucial unmet need to develop a safe and effective treatment for COVID-19 patients. Mesenchymal stem cells (MSCs) are widely used in basic science and in a variety of clinical trials. MSCs are able to engraft to the damaged tissues after transplantation and promote tissue regeneration, besides MSCs able to secrete immunomodulatory factors that suppress the cytokine storms. Moreover, the contribution of MSCs to prevent cell death and inhibit tissue fibrosis is well established. In the current review article, the potential mechanisms by which MSCs contribute to the treatment of COVID-19 patients are highlighted. Also, current trials that evaluated the potential of MSC-based treatments for COVID-19 are briefly reviewed.

"A Chain Only as Strong as Its Weakest Link": An Up-to-Date Literature Review on the Bidirectional Interaction of Pulmonary Fibrosis and COVID-19

The COVID-19 pandemic rapidly became a worldwide healthcare emergency affecting millions of people, with poor outcomes for patients with chronic conditions and enormous pressure on healthcare systems. Pulmonary fibrosis (PF) has been cited as a risk factor for a more severe evolution of COVID-19, primarily because its acute exacerbations are already associated with high mortality. We reviewed the available literature on biochemical, pathophysiological, and pharmacological mechanisms of PF and COVID-19 in an attempt to foresee the particular risk of infection and possible evolution of PF patients if infected with SARS-COV-2. We also analyzed the possible role of medication and risk factors (such as smoking) in the disease's evolution and clinical course. We found out that there is a complexity of interactions between coexisting idiopathic pulmonary fibrosis/interstitial lung disease (ILD) and COVID-19 disease. Also, patients recovering from severe COVID-19 disease are at serious risk of developing PF. Smokers seem to have, in theory, a chance for a better outcome if they develop a severe form of COVID-19 but statistically are at much higher risk of dying if they become critically ill.

Umbilical cord: an allogenic tissue for potential treatment of COVID-19

The COVID-19 pandemic has placed an unprecedented burden on health care systems and economies around the globe. Clinical evidences demonstrate that SARS-CoV-2 infection produces detrimental levels of pro-inflammatory cytokines and chemokines that can lead to acute respiratory distress syndrome (ARDS) and significant systemic organ damage. Currently, there is no definitive therapy for COVID-19 or associated complications, and with the hope of a safe and effective vaccine in the distant future, the search for an answer is paramount. Mesenchymal stem cells (MSCs) provide a viable option due to their immunomodulatory effects and tissue repair and regeneration abilities. Studies have demonstrated that compassionate use of MSCs can reduce symptoms associated with SARS-CoV-2 infection, eliminate fluid buildup, and act as a regenerative technique for alveolar damage; all in a safe and effective way. With multiple autologous sources available for MSCs, each with their own respective limitations, allogenic umbilical cord (UC) and/or UC-derived Wharton’s jelly (WJ) seem to be best positioned source to harvest MSCs to treat COVID-19 and associated symptoms. As an allogenic source, UC is readily available, easily obtainable, and is rich in immunomodulatory and regenerative factors. In this manuscript, we reviewed the current evidences and explored the potential therapeutic use of allogenic UC and/or WJ-derived MSCs for the treatment of COVID-19. Although, preliminary preclinical and clinical studies indicate that their use is safe and potentially effective, more multi-center, randomized, controlled trials are needed to adequately assess the safety and efficacy of UC and/or WJ-derived MSCs for the treatment of COVID-19.

New normal: two aspects of adipose tissue in COVID-19-treat and threat?

INTRODUCTION

Adipose-derived stromal cells (ADSCs) can be an important alternative in COVID-19 prevention, treatment, and subsequent sequelae repair. However, ACE-2 plays a common role in the pathogenesis of adipocyte hypertrophy and COVID 19.

AREAS COVERED

In this 'Perspective,' the author would like to emphasize the use of adipose tissue-derived stromal cells in COVID 19 and the issues that clinicians should pay attention to in fat graft applications in terms of adipose tissue-RAS relationship. The new normal for adipose tissue in COVID 19 will be highlighted.

EXPERT OPINION

ADSCs may potentially be used in COVID-19. However, it has been speculated that ACE2 receptors are responsible for the pathogenesis of adipose tissue overgrowth and may be a potential danger in terms of the relationship between ACE2 receptors and COVID19. We speculate that reducing the size of overgrown fat tissue by ultra-sharp blades and using near-normal adipocytes will create a 'new normal.'

Auxiliary role of mesenchymal stem cells as regenerative medicine soldiers to attenuate inflammatory processes of severe acute respiratory infections caused by COVID-19

Acute respiratory infections as one of the most common problems of healthcare systems also can be considered as an important reason for worldwide morbidity and mortality from infectious diseases. Coronaviruses are a group of well-known respiratory viruses that can cause acute respiratory infections. At the current state, the 2019 novel coronavirus is cited as the most worldwide problematic agent for the respiratory system. According to investigations, people with old age and underlying diseases are at higher risk of 2019 novel coronavirus infection. Indeed, they may show a severe form of the disease (with severe acute respiratory infections). Based on the promising role of cell therapy and regenerative medicine approaches in the treatment of several life-threatening diseases, it seems that applying cell-based approaches can also be a hopeful strategy for improving subjects with severe acute respiratory infections caused by the 2019 novel coronavirus. Herein, due to the amazing effects of mesenchymal stem cells in the treatment of various diseases, this review focuses on the auxiliary role of mesenchymal stem cells to reduce inflammatory processes of acute respiratory infections caused by the 2019 novel coronavirus.

The Coronavirus Pandemic (SARS-CoV-2): New Problems Demand New Solutions, the Alternative of Mesenchymal (Stem) Stromal Cells

Mesenchymal (stem) stromal cells (MSC) can be a therapeutic alternative for COVID-19 considering their anti-inflammatory, regenerative, angiogenic, and even antimicrobial capacity. Preliminary data point to therapeutic interest of MSC for patients with COVID-19, and their effect seems based on the MSC's ability to curb the cytokine storm caused by COVID-19. In fact, promising clinical studies using MSC to treat COVID-19, are currently underway. For this reason, now is the time to firmly consider new approaches to MSC research that addresses key issues, like selecting the most optimal type of MSC for each indication, assuming the heterogeneity of the donor-dependent MSC and the biological niche where MSC are located.

Rationale for the clinical use of adipose-derived mesenchymal stem cells for COVID-19 patients

In late 2019, a novel coronavirus (SARS-CoV-2) emerged in Wuhan, capital city of Hubei province in China. Cases of SARS-CoV-2 infection quickly grew by several thousand per day. Less than 100 days later, the World Health Organization declared that the rapidly spreading viral outbreak had become a global pandemic. Coronavirus disease 2019 (COVID-19) is typically associated with fever and respiratory symptoms. It often progresses to severe respiratory distress and multi-organ failure which carry a high mortality rate. Older patients or those with medical comorbidities are at greater risk for severe disease. Inflammation, pulmonary edema and an over-reactive immune response can lead to hypoxia, respiratory distress and lung damage. Mesenchymal stromal/stem cells (MSCs) possess potent and broad-ranging immunomodulatory activities. Multiple in vivo studies in animal models and ex vivo human lung models have demonstrated the MSC's impressive capacity to inhibit lung damage, reduce inflammation, dampen immune responses and aid with alveolar fluid clearance. Additionally, MSCs produce molecules that are antimicrobial and reduce pain. Upon administration by the intravenous route, the cells travel directly to the lungs where the majority are sequestered, a great benefit for the treatment of pulmonary disease. The in vivo safety of local and intravenous administration of MSCs has been demonstrated in multiple human clinical trials, including studies of acute respiratory distress syndrome (ARDS). Recently, the application of MSCs in the context of ongoing COVID-19 disease and other viral respiratory illnesses has demonstrated reduced patient mortality and, in some cases, improved long-term pulmonary function. Adipose-derived stem cells (ASC), an abundant type of MSC, are proposed as a therapeutic option for the treatment of COVID-19 in order to reduce morbidity and mortality. Additionally, when proven to be safe and effective, ASC treatments may reduce the demand on critical hospital resources. The ongoing COVID-19 outbreak has resulted in significant healthcare and socioeconomic burdens across the globe. There is a desperate need for safe and effective treatments. Cellular based therapies hold great promise for the treatment of COVID-19. This literature summary reviews the scientific rationale and need for clinical studies of adipose-derived stem cells and other types of mesenchymal stem cells in the treatment of patients who suffer with COVID-19.

A Review of SARS-CoV-2 and the Ongoing Clinical Trials

The sudden outbreak of 2019 novel coronavirus (2019-nCoV, later named SARS-CoV-2) in Wuhan, China, which rapidly grew into a global pandemic, marked the third introduction of a virulent coronavirus into the human society, affecting not only the healthcare system, but also the global economy. Although our understanding of coronaviruses has undergone a huge leap after two precedents, the effective approaches to treatment and epidemiological control are still lacking. In this article, we present a succinct overview of the epidemiology, clinical features, and molecular characteristics of SARS-CoV-2. We summarize the current epidemiological and clinical data from the initial Wuhan studies, and emphasize several features of SARS-CoV-2, which differentiate it from SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV), such as high variability of disease presentation. We systematize the current clinical trials that have been rapidly initiated after the outbreak of COVID-19 pandemic. Whereas the trials on SARS-CoV-2 genome-based specific vaccines and therapeutic antibodies are currently being tested, this solution is more long-term, as they require thorough testing of their safety. On the other hand, the repurposing of the existing therapeutic agents previously designed for other virus infections and pathologies happens to be the only practical approach as a rapid response measure to the emergent pandemic, as most of these agents have already been tested for their safety. These agents can be divided into two broad categories, those that can directly target the virus replication cycle, and those based on immunotherapy approaches either aimed to boost innate antiviral immune responses or alleviate damage induced by dysregulated inflammatory responses. The initial clinical studies revealed the promising therapeutic potential of several of such drugs, including favipiravir, a broad-spectrum antiviral drug that interferes with the viral replication, and hydroxychloroquine, the repurposed antimalarial drug that interferes with the virus endosomal entry pathway. We speculate that the current pandemic emergency will be a trigger for more systematic drug repurposing design approaches based on big data analysis.

PM2.5 collecting in a tire manufacturing plant affects epithelial differentiation of human umbilical cord derived mesenchymal stem cells by Wnt/β-catenin pathway

Mesenchymal stem cells (MSCs) can differentiate into pulmonary epithelial cells by Wnt/β-catenin pathway and promote lung repair. However, whether fine particulate matter (PM_2.5) could affect Wnt pathway and finally reduce the ability of MSCs to differentiate into epithelial cells is still unknown. This study aimed to investigate whether PM_2.5 could inhibit the epithelial differentiation of human umbilical cord-derived MSCs cells (hUCMSCs) and the related underlying mechanism. hUCMSCs were incubated with different concentrations of PM_2.5. Then, the cell viability, reactive oxygen species level, and single-cell sphere formation were assessed. The underlying mechanism of PM_2.5 in epithelial differentiation of hUCMSCs was further evaluated by co-culturing hUCMSCs with A549 cells. Our results demonstrated that PM_2.5 exposures could affect the expressions of β-catenin and lung epithelial markers (zonula occludens-1 (ZO-1); cytokeratins 5 and 19) in the co-cultured hUCMSCs. The Wnt/β-catenin pathway is involved in regulating the epithelial differentiation of MSCs. As expected, co-treatment with Wnt3a, which is the activator of the Wnt pathway, attenuated the downregulation of lung epithelial markers (ZO-1; cytokeratins 5 and 19) and paracrine factors (keratinocyte growth factor and hepatocyte growth factor) caused by PM_2.5. Altogether, these results demonstrated that PM_2.5 could affect the epithelial differentiation of hUCMSCs via the Wnt/β-catenin pathway.

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.

Induced Pluripotent Stem Cells Attenuate Endothelial Leakage in Acute Lung Injury via Tissue Inhibitor of Metalloproteinases-1 to Reduce Focal Adhesion Kinase Activity

Induced pluripotent stem cells (iPSCs) can reduce the severity of endotoxin-induced acute lung injury (ALI). However, the interaction between iPSCs and vascular endothelium remains unclear. In this study, we investigated the effects of iPSCs in moderating pulmonary endothelial leakage in endotoxin-induced ALI. Murine iPSCs were delivered intravenously to male C57BL/6 mice (8-12 weeks old) 4 hours after intratracheal lipopolysaccharide (LPS) delivery. Histology, blood and bronchoalveolar lavage fluid (BALF) cytokine and junctional protein assays, and regulatory signaling pathway assays were performed 24 hours later. Human umbilical vein endothelial cells (HUVECs) were used as a model of junctional protein-expressing cells and stimulated with LPS. Our results showed that iPSC treatment alleviated histological signs of ALI, protein leakage, and proinflammatory cytokines. iPSC therapy restored vascular endothelial cadherin (VE-cadherin) expression in ALI mouse lungs. In HUVECs, human iPSCs (hiPSCs) restored disrupted VE-cadherin expression and reduced the activity of Snail and focal adhesion kinase (FAK) phosphorylation in Tyr397 in response to LPS. iPSC-conditioned medium contained extra antiangiogenic factor of tissue inhibitor of metalloproteinases-1 (TIMP-1) compared with control medium. TIMP-1 inhibition diminished the beneficial effects of iPSC-conditioned medium in ALI mice. Our study suggested that iPSCs attenuate endothelial cell leakage in endotoxin-induced ALI via a mechanism involving TIMP-1 and the FAK/Snail pathway. Stem Cells 2019;37:1516-1527.

Mesenchymal stem cells with downregulated Hippo signaling attenuate lung injury in mice with lipopolysaccharide‑induced acute respiratory distress syndrome

Mesenchymal stem cell (MSC)-mediated repair of injured alveolar epithelial cells is a promising potential cure for acute respiratory distress syndrome (ARDS); however, the repairing effect of MSCs is limited by poor homing and differentiation. Our previous study revealed that the inhibition of the Hippo signaling pathway promotes the proliferation, migration and differentiation of MSCs in vitro, leading to the hypothesis that MSCs with downregulated Hippo signaling could further ameliorate lipopolysaccharide (LPS)-induced ARDS in vivo. In the current study, mouse bone marrow-derived MSCs (mMSCs) with downregulated Hippo signaling were constructed by shRNA-mediated knockdown of large tumor suppressor kinase 1 (Lats1) and were intratracheally administered to LPS-induced mouse models of ARDS. The inhibition of Hippo signaling increased the retention of mMSC in ARDS lung tissue and their differentiation toward alveolar type II epithelial cells. Furthermore, mMSCs with downregulated Hippo signaling led to a decreased lung wet weight/body weight ratio, decreased total protein and albumin concentrations in bronchoalveolar lavage fluid, decreased levels of proinflammatory factors and increased levels of anti-inflammatory factors. Finally, mMSCs with downregulated Hippo signaling improved pathological changes and decreased pulmonary fibrosis in lungs of mice with ARDS. These results suggest that the inhibition of the Hippo signaling pathway in mouse mMSCs by knockdown of Lats1 could further improve the protective effects of mMSCs against epithelial damage and the therapeutic potential of mMSCs on mice with ARDS.

Bone marrow stem cells modified with human interleukin 10 attenuate acute rejection in rat lung allotransplantation

OBJECTIVES

The aim of this study was to investigate new therapeutic options to attenuate acute rejection in a rat lung allograft model. Cell-based gene therapies have recently been reported as a novel curative option in acute and chronic diseases for which conventional treatments are not available. We studied the effect of human interleukin 10 (hIL-10) on expressing bone marrow-derived mesenchymal stem cells (BMSCs) in combination with cyclosporine A (CsA) on acute rejection of lung allografts in the rat.

METHODS

Lung allotransplantation was performed from male Brown Norway donor to male Fisher (F344) rats. Rat BMSCs were transfected with hIL-10 in vitro and introduced in the graft prior to implantation. Group A (n = 5) received CsA intraperitoneally (2.5 mg/kg body weight) for 5 days post-transplant; Group B (n = 5) received BMSC and CsA and Group C (n = 5) received hIL-10-BMSC before implantation and CsA. Graft function was assessed by blood gas levels only from the graft on day 5; tissue was sampled for histological grading of rejection and measurement of the wet-to-dry ratio.

RESULTS

All Group A control animals showed severe signs of rejection. On Day 5, all grafts in Group C showed improved gas exchange (mean arterial partial pressure of oxygen 222.2 ± 40.38 mmHg vs 92.36 ± 20.92 mmHg in Group B and 42.72 ± 18.07 mmHg in Group A). Histological examination revealed moderate-to-severe rejection in all animals in Group A [International Society for Heart and Lung Transplantation Level III B (ISHLT)] in contrast to low-to-moderate rejection in Group B (II-IIIA) and much improved histological grade in Group C (I-IIA). Moreover, the wet-to-dry ratio was also reduced in Group C (4.8 ± 1.19 compared with 4.78 ± 0.62 in Group B and 9.36 ± 0.90 in Group A).

CONCLUSIONS

The hIL-10 BMSC represent a promising novel method for localized cell-based gene therapy for acute rejection in a rat lung allograft model.

Inhibition of NLRP9b attenuates acute lung injury through suppressing inflammation, apoptosis and oxidative stress in murine and cell models

Acute lung injury (ALI), known a severe disease along with high morbidity and mortality, is lacking of specific therapies. Inflammation, apoptosis and oxidative stress are critical pathologies that contribute to ALI. Recently, there is study indicated that NLRP9b, a NOD-like receptor (NLR) member, is critical in modulation of inflammatory response. However, the effects of NLRP9b on sepsis-associated ALI, and the underlying molecular mechanism have not been understood. In the present study, the wild type (WT) and NLRP9b-knockout (NLRP9b^-/-) mice with C57B/L6 background were subjected to a cecal ligation and puncture (CLP) for ALI murine model establishment. The findings indicated that NLRP9b^-/- improved the survival rate of CLP-induced ALI mice, and inhibited pulmonary histopathological alterations, inflammation, and apoptosis. NLRP9b^-/- reduced the activation of inhibitor of κBα/nuclear factor kappa B (IκBα/NF-κB), apoptosis-associated speck-like protein containing a Caspase-recruitment domain (ASC)/Casapse-1 and Caspase-3/poly (ADP-ribose) polymerase (PARP) signaling pathways in CLP-challenged mice with ALI. In vitro, mouse epithelial cells (MLE-12) were incubated with lipopolysaccharide (LPS) or recombinant NLRP9b caused a significant increased of pro-inflammatory cytokines or chemokine, and reactive oxygen species (ROS) generation; however, these changes were markedly alleviated by NLRP9-knockdown using its specific siRNA sequence. Pre-treatment of MLE-12 cells with ROS scavenger of N-acetylcysteine (NAC) remarkably decreased lipopolysaccharide (LPS)- and rMuNLRP9-induced production of ROS, and the secretion of inflammatory cytokines or chemokine, as well as the activity of IκBα/NF-κB, ASC/Casapse-1 and Caspase-3/PARP signaling pathways. Together, the findings here suggested that NLRP9b played an essential role in lung inflammation, apoptosis and oxidative stress of sepsis-induced ALI animal model or in LPS-induced MLE-12 cells, providing that NLRP9b inhibition might be a potential therapeutic option for ALI.

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.

Application of stem cells in tissue engineering for defense medicine

The dynamic nature of modern warfare, including threats and injuries faced by soldiers, necessitates the development of countermeasures that address a wide variety of injuries. Tissue engineering has emerged as a field with the potential to provide contemporary solutions. In this review, discussions focus on the applications of stem cells in tissue engineering to address health risks frequently faced by combatants at war. Human development depends intimately on stem cells, the mysterious precursor to every kind of cell in the body that, with proper instruction, can grow and differentiate into any new tissue or organ. Recent reports have suggested the greater therapeutic effects of the anti-inflammatory, trophic, paracrine and immune-modulatory functions associated with these cells, which induce them to restore normal healing and tissue regeneration by modulating immune reactions, regulating inflammation, and suppressing fibrosis. Therefore, the use of stem cells holds significant promise for the treatment of many battlefield injuries and their complications. These applications include the treatment of injuries to the skin, sensory organs, nervous system tissues, the musculoskeletal system, circulatory/pulmonary tissues and genitals/testicles and of acute radiation syndrome and the development of novel biosensors. The new research developments in these areas suggest that solutions are being developed to reduce critical consequences of wounds and exposures suffered in warfare. Current military applications of stem cell-based therapies are already saving the lives of soldiers who would have died in previous conflicts. Injuries that would have resulted in deaths previously now result in wounds today; similarly, today's permanent wounds may be reduced to tomorrow's bad memories with further advances in stem cell-based therapies.