"The role of extracellular vesicle miRNAs in Mesenchymal Stem Cells' effects on macrophage modulation in ARDS"

Inflammation is the way in which the body reacts to infection, irritation or other injury. Normally, inflammation is one way the body heals and copes with the infection, However, when dysregulated in certain condition such as sepsis it can lead to severe damage and impair organ function. Recently more and more clinicians and basic scientists attention is drawn to cell-based therapies. A key advantage of cell based therapy compared to pharmacologic treatment is that cells can actively respond to the local microenvironment and exert multiple beneficial effects, modulating several injurious and reparative pathways in complex disease process.
One of the most promising candidate for a cell based therapy are cells termed Mesenchymal Stem Cells (MSCs), which represent one kind of adult stem cells (can be easily isolated from tissues of adult patients or healthy volunteers), because of this, there is no ethical issues. MSCs could easily be propagated and manipulated under laboratory conditions and have capacity to differentiate into different cell types of the body. Importantly, long term research has shown their safety in terms of developing tumors.
Multiple preclinical animal studies conducted by our group as well as by other investigators showed that MSCs indeed have protective effect when administered as a treatment for inflammatory conditions. Among several beneficial effects, their administration always is associated with drastically reduced inflammation, however the mechanisms of this phenomenon are still unclear and data on their interaction with the immune cells remain unsufficient and controversial. To translate MSCs into the clinical practice it is essential that we have more precise understanding of their mechanism of action. In this study we are seeking to establish the MSCs' response to a true physiological inflammatory environment. We have established in vitro models of primary human cells stimulated with samples from patients available from ongoing clinical trials, as the most physiologycally relevant mimic of inflammatory microenvironment.
In this project we will investigate the novel mechanism of MSC effect mediated through the capacity of these cells to release small membrane wrapped "exracellular vesicles". We are specifically interested in those vesicles which contain regulatory molecules, termed miRNAs.
After establishing the importance of miRNA transfer via extracellular vesicles to the primary human cells we will validate our findings in the animal model.
Finally we have a unique opportunity to validate our findings on MSC therapeutic efficacy by analysing clinical samples of patients who had entered into our clinical trial for MSCs in ARDS.The principle anticipated output is the establishment of a defined and robust mechanism of immunomodulatory action of MSC cell therapy which inform further trials for MSCs and MSC-derived extracellular vesicles. These findings will also inform potency assays for cell manufacturing purposes and provide insights into future MSC engineering to improve their therapeutic efficacy.The mechanistic data from this study will bring MSCs closer to the patient.

Acute Respiratory Distress Syndrome (ARDS) is a major cause of acute respiratory failure in critically ill patients, with no effective treatment. We have demonstrated that Mesenchymal Stem/Stromal Cells (MSCs) hold significant therapeutic promise for this condition. MSCs are rapidly progressing to clinical trials across the world, and we will shortly commence phase I/II clinical trial of MSCs in ARDS under a Wellcome Trust funding. The major challenge for rational development of MSC-based therapy is the lack of clear understanding of mechanisms of MSC action in the inflammatory environment, which poses a roadblock for clinical translation. Regulatory bodies highlight the need for evidence of therapeutic mechanism of action to be incorporated into clinical MSC Investigation Medicinal Product Dossiers. This knowledge is critical for the rational development of MSC-based therapies to ensure maximum realisation of their therapeutic potential. In this project, we will investigate immunomodulatory mechanisms of MSCs mediated by miRNAs secreted in the MSC-derived extracellular vesicles using clinically relevant in vitro and in vivo models of ARDS and clinical samples of ARDS patients who has recieved MSCs as a treatment.
The anticipated output is an understanding of the specific mechanisms of the immunomodulatory action for MSC cell therapy and MSC extracellular vesicles in ARDS thus enhancing the potential of translation into the clinic. Results from these studies will be timely to inform the design of the subsequent phase III trials and phase I/II trials for MSC extracellular vesicles. miRNAs found to be functionally important may be exploited therapeutically independently of MSCs. The results from these studies may also have relevance for other inflammatory conditions

The mortality associated with ARDS remains high, between 30-40%. It is a common condition affecting all age groups with an estimated incidence of 79 per 100, 000 patient years. ARDS has significant resource implications, prolonging intensive care unit (ICU) and hospital stay, and requiring rehabilitation in the community. The cost per ICU bed-day in the UK exceeds £1800 and delivery of critical care to patients with ARDS accounts for a significant proportion of ICU capacity. Only 54% of survivors are able to return to work 12 months after hospital discharge. The high incidence, mortality, longterm consequences and economic costs mean that ARDS is an extremely important problem.
Results from this work can be easily translated into the development of optimised MSC based therapy. Investigation of the MSC derived extracellular vesicles (EVs) may lead to further development of EV based therapies which would make a more uniform and predictable product compared to whole cell administration. In the long-term this research will have implications to improve health and wellbeing in the UK and globally. Hastening the recovery from ARDS would lead to a shorter ICU stay, with attendant reductions in nosocomial infection, and other critical illness complications including neuropathy/myopathy/ delirium. This would have direct short term benefits to the patients themselves, including reduced hospital stay and complications, leading hopefully to a better long term functional outcome, with more patients returning to work. Additionally this would lead to a reduced burden for carers and reduced cost of stay and long term healthcare provision.
Understanding the mechanisms mediating effect of MSC in ARDS will lead to identification of other therapeutic targets (independently of MSC), (e.g. specific miRNAs) with the potential for further development as a pharmacological treatment for ARDS.
In addition to this condition, the understanding of mechanisms of MSC effects will open new avenues of research for other diseases mediated by excessive inflammation, both in the lung and in other organs.
With this in mind, this research is likely to impact other researchers both academically and industrially in development of follow-on therapeutics and biomaterials that can exploit these effects. Therefore it is tangible that if successful, this project could lead on to the development of other daughter therapeutics that could not only help patients suffering other inflammatory diseases, but also generate new R&D jobs and revenue for the UK.
This proposal is at the forefront of rapidly emerging MSC field and of global competitiveness. Results from this research will be published in high impact journals and presented at the top international and national conferences. This will gain further recognition of the QUB as an internationally competitive University contributing to the reputation of the UK as a world leader in the biosciences.
Results of the miRNA sequensing will be deposited into the public database Gene Expression Omnibus annd will be available to wide scientific community.
Results from this project have the potential to attract R&D investment from biotechnology and pharmaceutical companies (e.g. through development of the potency assays important in the cell manufacturing process or may provide new insights into the cell manipulation in order to improve efficacy) . Any commercialisation would increase wealth and foster economic competitiveness in the UK.
MSC-derived EVs have a great potential to be developed into therapeutic for a range of conditions beyond ARDS.