Immunomodulation of Mesenchymal Stem Cells in Acute Lung Injury: From Preclinical Animal Models to Treatment of Severe COVID-19

Interplay between pulmonary epithelial stem cells and innate immune cells contribute to the repair and regeneration of ALI/ARDS

Mammalian lung is the important organ for ventilation and exchange of air and blood. Fresh air and venous blood are constantly delivered through the airway and vascular tree to the alveolus. Based on this, the airways and alveolis are persistently exposed to the external environment and are easily suffered from toxins, irritants and pathogens. For example, acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a common cause of respiratory failure in critical patients, whose typical pathological characters are diffuse epithelial and endothelial damage resulting in excessive accumulation of inflammatory fluid in the alveolar cavity. The supportive treatment is the main current treatment for ALI/ARDS with the lack of targeted effective treatment strategies. However, ALI/ARDS needs more targeted treatment measures. Therefore, it is extremely urgent to understand the cellular and molecular mechanisms that maintain alveolar epithelial barrier and airway integrity. Previous researches have shown that the lung epithelial cells with tissue stem cell function have the ability to repair and regenerate after injury. Also, it is able to regulate the phenotype and function of innate immune cells involving in regeneration of tissue repair. Meanwhile, we emphasize that interaction between the lung epithelial cells and innate immune cells is more supportive to repair and regenerate in the lung epithelium following acute lung injury. We reviewed the recent advances in injury and repair of lung epithelial stem cells and innate immune cells in ALI/ARDS, concentrating on alveolar type 2 cells and alveolar macrophages and their contribution to post-injury repair behavior of ALI/ARDS through the latest potential molecular communication mechanisms. This will help to develop new research strategies and therapeutic targets for ALI/ARDS.

Protective Effects of Danmu Extract Syrup on Acute Lung Injury Induced by Lipopolysaccharide in Mice through Endothelial Barrier Repair

OBJECTIVE

To investigate the effects of Danmu Extract Syrup (DMS) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice and explore the mechanism.

METHODS

Seventy-two male Balb/C mice were randomly divided into 6 groups according to a random number table (n=12), including control (normal saline), LPS (5 mg/kg), LPS+DMS 2.5 mL/kg, LPS+DMS 5 mL/kg, LPS+DMS 10 mL/kg, and LPS+Dexamethasone (DXM, 5 mg/kg) groups. After pretreatment with DMS and DXM, the ALI mice model was induced by LPS, and the bronchoalveolar lavage fluid (BALF) were collected to determine protein concentration, cell counts and inflammatory cytokines. The lung tissues of mice were stained with hematoxylin-eosin, and the wet/dry weight ratio (W/D) of lung tissue was calculated. The levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1 β in BALF of mice were detected by enzyme linked immunosorbent assay. The expression levels of Claudin-5, vascular endothelial (VE)-cadherin, vascular endothelial growth factor (VEGF), phospho-protein kinase B (p-Akt) and Akt were detected by Western blot analysis.

RESULTS

DMS pre-treatment significantly ameliorated lung histopathological changes. Compared with the LPS group, the W/D ratio and protein contents in BALF were obviously reduced after DMS pretreatment (P<0.05 or P<0.01). The number of cells in BALF and myeloperoxidase (MPO) activity decreased significantly after DMS pretreatment (P<0.05 or P<0.01). DMS pre-treatment decreased the levels of TNF-α, IL-6 and IL-1 β (P<0.01). Meanwhile, DMS activated the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) pathway and reversed the expressions of Claudin-5, VE-cadherin and VEGF (P<0.01).

CONCLUSIONS

DMS attenuated LPS-induced ALI in mice through repairing endothelial barrier. It might be a potential therapeutic drug for LPS-induced lung injury.

Successful salvage of a severe COVID-19 patient previously with lung cancer and radiation pneumonitis by mesenchymal stem cells: a case report and literature review

During the COVID-19 pandemic, elderly patients with underlying condition, such as tumors, had poor prognoses after progressing to severe pneumonia and often had poor response to standard treatment. Mesenchymal stem cells (MSCs) may be a promising treatment for patients with severe pneumonia, but MSCs are rarely used for patients with carcinoma. Here, we reported a 67-year-old female patient with lung adenocarcinoma who underwent osimertinib and radiotherapy and suffered from radiation pneumonitis. Unfortunately, she contracted COVID-19 and that rapidly progressed to severe pneumonia. She responded poorly to frontline treatment and was in danger. Subsequently, she received a salvage treatment with four doses of MSCs, and her symptoms surprisingly improved quickly. After a lung CT scan that presented with a significantly improved infection, she was discharged eventually. Her primary disease was stable after 6 months of follow-up, and no tumor recurrence or progression was observed. MSCs may be an effective treatment for hyperactive inflammation due to their ability related to immunomodulation and tissue repair. Our case suggests a potential value of MSCs for severe pneumonia that is unresponsive to conventional therapy after a COVID-19 infection. However, unless the situation is urgent, it needs to be considered with caution for patients with tumors. The safety in tumor patients still needs to be observed.

Clinical Trials of Mesenchymal Stem Cells for the Treatment of COVID 19

Mesenchymal Stem Cells (MSCs) are being investigated as a treatment for a novel viral disease owing to their immunomodulatory, anti-inflammatory, tissue repair and regeneration characteristics, however, the exact processes are unknown. MSC therapy was found to be effective in lowering immune system overactivation and increasing endogenous healing after SARS-CoV-2 infection by improving the pulmonary microenvironment. Many studies on mesenchymal stem cells have been undertaken concurrently, and we may help speed up the effectiveness of these studies by collecting and statistically analyzing data from them. Based on clinical trial information found on clinicaltrials. gov and on 16 November 2020, which includes 63 clinical trials in the field of patient treatment with COVID-19 using MSCs, according to the trend of increasing studies in this field, and with the help of meta-analysis studies, it is possible to hope that the promise of MSCs will one day be realized. The potential therapeutic applications of MSCs for COVID-19 are investigated in this study.

Adipose tissue-derived mesenchymal stromal cells attenuate acute lung injury induced by trauma and haemorrhagic shock

BACKGROUND

Mesenchymal stromal cells (MSCs) have shown promising therapeutic options for acute lung injury (ALI) caused by multiple factors. Here, we evaluated the therapeutic potential of adipose tissue-derived mesenchymal stromal cells (ADSCs) in trauma and hemorrhagic shock (THS)-induced ALI.

METHODS

ALI model induced by THS was constructed by fractures plus abdominal trauma plus acute hemorrhage plus fluid resuscitation. The ADSCs group rats were generated by injecting 2 × 106 ADSCs at 0 and 1 h after THS. The sham, ALI, and ADSCs group rats were sacrificed at 24 h after resuscitation. The changes in lung histopathology, total protein in bronchoalveolar lavage fluid (BALF), mRNA expression of pro-inflammatory/anti-inflammatory cytokines, antioxidant, and anti-apoptotic indicator, and the activity of Toll-like receptor 4 (TLR4) signaling in lung tissues were evaluated.

RESULTS

Administration of the ADSCs reversed ALI induced by THS, including lung histopathological changes/scores, and BALF total protein concentration. Additionally, ADSCs therapy also significantly down-regulated mRNA expression of pro-inflammatory TNF-α, IL-1β, and IL-6, up-regulated mRNA expression of anti-inflammatory IL-10, anti-apoptotic molecule Bcl-2, and anti-oxidative molecule HO-1 in THS rats. Furthermore, ADSCs suppressed the expression of TLR4 in lung tissue.

CONCLUSION

Our data show that ADSCs administration can exert therapeutic effects on THS-induced ALI in rats and may provide beneficial in preventative strategies for ALI.

Pathological role of inflammation in ocular disease progress and its targeting by mesenchymal stem cells (MSCs) and their exosome; current status and prospect

Because of their unique capacity for differentiation to a diversity of cell lineages and immunosuppressive properties, mesenchymal stem cells (MSC) are being looked at as a potential new treatment option in ophthalmology. The MSCs derived from all tissue sources possess immunomodulatory attributes through cell-to-cell contact and releasing a myriad of immunomodulatory factors (IL-10, TGF-β, growth-related oncogene (GRO), indoleamine 2,3 dioxygenase (IDO), nitric oxide (NO), interleukin 1 receptor antagonist (IL-1Ra), prostaglandin E2 (PGE2)). Such mediators, in turn, alter both the phenotype and action of all immune cells that serve a pathogenic role in the progression of inflammation in eye diseases. Exosomes from MSCs, as natural nano-particles, contain the majority of the bioactive components of parental MSCs and can easily by-pass all biological barriers to reach the target epithelial and immune cells in the eye without interfering with nearby parenchymal cells, thus having no serious side effects. We outlined the most recent research on the molecular mechanisms underlying the therapeutic benefits of MSC and MSC-exosome in the treatment of inflammatory eye diseases in the current article.

Cell-Based Biomaterials for Coronavirus Disease 2019 Prevention and Therapy

Coronavirus disease 2019 (COVID-19) continues to threaten human health, economic development, and national security. Although many vaccines and drugs have been explored to fight against the major pandemic, their efficacy and safety still need to be improved. Cell-based biomaterials, especially living cells, extracellular vesicles, and cell membranes, offer great potential in preventing and treating COVID-19 owing to their versatility and unique biological functions. In this review, the characteristics and functions of cell-based biomaterials and their biological applications in COVID-19 prevention and therapy are described. First the pathological features of COVID-19 are summarized, providing enlightenment on how to fight against COVID-19. Next, the classification, organization structure, characteristics, and functions of cell-based biomaterials are focused on. Finally, the progress of cell-based biomaterials in overcoming COVID-19 in different aspects, including the prevention of viral infection, inhibition of viral proliferation, anti-inflammation, tissue repair, and alleviation of lymphopenia are comprehensively described. At the end of this review, a look forward to the challenges of this aspect is presented.

Bioengineered stem cell membrane functionalized nanoparticles combine anti-inflammatory and antimicrobial properties for sepsis treatment

BACKGROUND

Sepsis is a syndrome of physiological, pathological and biochemical abnormalities caused by infection. Although the mortality rate is lower than before, many survivors have persistent infection, which means sepsis calls for new treatment. After infection, inflammatory mediators were largely released into the blood, leading to multiple organ dysfunction. Therefore, anti-infection and anti-inflammation are critical issues in sepsis management.

RESULTS

Here, we successfully constructed a novel nanometer drug loading system for sepsis management, FZ/MER-AgMOF@Bm. The nanoparticles were modified with LPS-treated bone marrow mesenchymal stem cell (BMSC) membrane, and silver metal organic framework (AgMOF) was used as the nanocore for loading FPS-ZM1 and meropenem which was delivery to the infectious microenvironments (IMEs) to exert dual anti-inflammatory and antibacterial effects. FZ/MER-AgMOF@Bm effectively alleviated excessive inflammatory response and eliminated bacteria. FZ/MER-AgMOF@Bm also played an anti-inflammatory role by promoting the polarization of macrophages to M2. When sepsis induced by cecal ligation and puncture (CLP) challenged mice was treated, FZ/MER-AgMOF@Bm could not only reduce the levels of pro-inflammatory factors and lung injury, but also help to improve hypothermia caused by septic shock and prolong survival time.

CONCLUSIONS

Together, the nanoparticles played a role in combined anti-inflammatory and antimicrobial properties, alleviating cytokine storm and protecting vital organ functions, could be a potential new strategy for sepsis management.

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.

Regenerative medicine in lung diseases: A systematic review

Regenerative medicine has opened the door to the exploration of new therapeutic methods for the treatment of various diseases, especially those associated with local or general disregulation of the immune system. In pulmonary diseases, new therapeutic strategies have emerged that are aimed at restoring functional lung tissue rather than alleviating symptoms. These strategies focus on tissue regeneration using stem cells and/or their derivatives or replacement of dysfunctional tissue using biomedical engineering. Animal health can directly benefit from regenerative therapy strategies and also serve as a translational experimental model for human disease. Several clinical trials have been conducted to evaluate the effects of cellular treatment on inflammatory lung disease in animals. Data reported to date show several beneficial effects in ex vivo and in vivo models; however, our understanding of the mechanisms that regenerative therapies exert on diseased tissues remains incomplete.