Enhancement of lung tissue regeneration and functional recovery following an acute pulmonary insult by regenerative therapy based on the use of heparan sulfate mimetics (HSM) is a promising approach for the treatment of diffuse alveolar damage (DAD), observed in acute respiratory distress syndrome (ARDS), acute exacerbations of fibrotic interstitial lung diseases or severe COVID-19 pneumonitis. The beneficial effects of HSM would be mainly related to the regeneration of the injured tissue by restructuring the destroyed matrix, protecting the cellular communicating peptides (growth factors, cytokines, chemokines), and by limiting the fibrosis usually observed during the repair process. Using of innovative approaches and models developed by 4 partners including a private one, the MAT-PL project will explore the ability of a heparan sulphate mimetic agent (OTR4132) to reduce inflammation, dysregulated angiogenesis and fibrosis, and improves the outcome of acute pulmonary injuries characteristic of DAD, thus opening a new approach for the prevention and the treatment of lung fibrosis.

It is now well established that the extracellular matrix (ECM) and heparan sulfates (HS) are a key regulator of the cellular brain microenvironment. In the MaTTau project, we propose a new strategy to reconstruct the cellular microenvironment in the neurodegenerating brain in the case of tauopathies by rebuilding the ECM scaffold and promoting homeostasis with OTR4132, a HS mimetic which will restore the glycanic ECM, the blood-brain barrier (BBB) and protect the brain cells using the rTg4510 mouse model of tau pathology. Indeed, “tauopathies” include heterogenous neurodegenerative disorders characterized by abnormal deposition of the microtubule-associated protein tau (MAPT) in neurons and, at lower levels, in oligodendrocytes, astrocytes and extracellular space, with symptoms of dementia and parkinsonism. The emerging evidence shows that restoring ECM and HS homeostasis and then the regenerative microenvironment can have drastic consequences on slowing down the progression of the disease, brain speed improvement and recovery. Therefore, HS appeared to be the key elements that promote recovery when ECM niche is lost/altered in injured or degenerating brain tissue. Our preliminary studies highlighted the neurotrophic activity of OTR4132, assessed by neurite outgrowth, and decrease of tau pathology readouts in vitro in a dose-response manner. Additionally, RGTA®-based HS mimetic OTR4132 is capable of significantly protecting the brain against stroke injuries and neurodegeneration leading to BBB disruption, which also induces neurofibrillary tangle-like tauopathy as observed in Alzheimer patients. Recently, we showed the neuroprotective effect of OTR4132 in brain ischemia reperfusion models of stroke in vivo. In addition, by evaluating the regulation of the inflammatory process associated with the fate of the abnormal tau protein and by studying the protein interactions of OTR4132, we will highlight the mechanisms involved in these processes.

Regenerative therapy based on the use of mesenchymal stem cells (MSC) is a promising approach for the treatment of stroke. The beneficial effects of MSC appears to be mainly related to the secretion of cellular factors and/or extracellular vesicles (EV). Heparan sulfates present on the surface of producing and recipient cells as well as on EV could play a critical role in the EV-mediated communication. The MAESTROVE project will explore, through the use of innovative approaches and models developed by 4 partners, the ability of combining human MSC-derived EV with a HS mimetic (HSm) agent, i.e. OTR4132, to enhance EV-mediated tissue regeneration and functional recovery following stroke, thus opening a new and rapid perspective for a development more easily industrialized for the treatment of stroke. The research hypothesis of the project lies on the fact that OTR4132 will create/restore a favourable tissue environment in which MSC-derived EV will be satisfactorily trapped and thus exert their beneficial effects in an optimal manner in the damaged brain tissue after stroke. Moreover, in vitro MSC priming with OTR4132 could improve EV biogenesis, cargo composition and regenerative properties. Combining HSm-based matrix therapy and MSC-derived EV therapy has never been studied. Another originality of this project is to test a priming strategy of MSC with this HSm-based matrix therapy to improve EV cargo constitution. This project will also evaluate for the first time a high-yield and scalable turbulence EV production approach for post-ischemic stroke treatment. This therapeutic strategy will be tested in relevant animal models of stroke towards the clinic, including the integration of the main comorbidity factor, i.e. the pre-existence of chronic arterial hypertension and an original non-human primate model. Overall, this project aims to provide an improved EV-based therapy that could represent a new clinically cell-free feasible paradigm for stroke. MAESTROVE gathers 4 partners with complementary expertise, most of them collaborating for a long time together with publications, patents and joint funding including 3 academic laboratories (Partner 1: ISTCT unit, Partner 3: Gly-CRRET unit and Partner 4: MSC unit) and 1 SME (Partner 2: OTR3). This project is subdivided into 5 Work Packages with WP1 for project management; WP2 for EV production by turbulence and characterization; WP3 for in vitro potency studies of EV (derived from MSC primed or not with OTR4132) in association or not with OTR4132 on neuronal, glial and endothelial cells survival submitted to an ischemic-like stress; WP4 for effects of combined therapies (OTR4132/EV) in different stroke models in the rat and marmoset; WP5 for effects of combined therapies (OTR4132/EV) on endogenous GAG modifications induced by stroke and blood markers identification of treatment efficacy. The MAESTROVE project proposes to develop a new therapy concept with the combination of OTR4132 and EV produced by human MSC. The success of the project is strongly supported by the proven effectiveness of OTR4132 and combined OTR4132/MSC in stroke tissues. Partner 2 has exclusive and worldwide rights for the engineering of matrix agents (RGTA®, ReGeneraTing Agents including OTR4132) and its applications in nervous system pathologies. Besides, the development of GMP EV production by turbulence from human MSC is on ingoing for a future clinical via a bioproduction start-up (EverZom) exploiting the patent from Partner 4.

IXBONE is a scientific proposal to find strategies for facial bone regeneration in the case of bone hypoplasia and in ischemic conditions (irradiated mandible after oral cancer). Cancer of the upper aero digestive tract is one of the most frequent cancers. Squamous cell carcinomas of the upper aero-digestive tract currently remain a major health challenge, with more than 263,000 new cases per year worldwide. In France, squamous cell carcinoma is the fourth cancer in order of frequency in men after prostate, lung and bowel cancers. In Europe, France has the highest head and neck cancer mortality and ranks in 3rd position just after Hong Kong and Singapore. Mandibular osteoradionecrosis (ORN) is a severe side effect of radiotherapy which affects 5% of treated patients, despite preventive efforts. ORN leads to mandibular fractures, deglutition and phonation disorders, and has a drastic impact on patient quality of life. The gold standard treatment is the autologous bone graft but, its difficult accessibility, the negative consequences of harvesting, and the limited quantity available require the need of alternative and reproducible solutions. The use of these bone morphogenic proteins is still difficult in children and not possible following cancer. The combination of Total Bone Marrow (TBM) associated with Biphasic Calcium Phosphate (BCP) has proven to be a simple and effective alternative method to tissue engineering strategies; however, this strategy is not yet able to replace the gold standard procedure due to the lack of reproducibility of TBM harvesting and due to the poor healing potential of the host tissue. IXBONE proposes a biomaterials cell-assisted therapy procedure to improve bone healing in patients suffering from ORN. We propose an innovative minimally-invasive strategy combining various skills (i) injectable biomaterials (ii) matrix therapy and (iii) stem cell therapy using allogenic mesenchymal stromal cells (MSC). Then IXBONE proposal takes into account the lack of the actual procedures. MSC will be laden in particles of hydrogel to allow protection and are included in an injectable bone substitute with specific synthetic sulfated sugar polymers that mimic GAGs called (RGTA) to increase their paracrine effects. This advanced biomaterial will be developed to also increase the osteoconductive and osteogenesis capacities. Part of the project aims to understand the behavior of the MSCs in this advanced-biomaterial, in particular, their bioactive activities (proteome, exosomes and miRNA). This new strategy will be tested in a rat model of ORN relevant to the human disease, already developed by the consortium. The therapeutic benefit will be evaluated on bone structure and vascularization using high resolution micro-scanners. We also have transgenic animal models to follow the engrafted cells as well as immunology and histology skills to evaluate the mechanism of action of the therapeutic benefit. The impact of IXBONE could be at various levels. The first is to propose the minimally-invasive strategy to patients with the very life threatening ORN disease. Indeed, the consortium includes clinicians that are already involved in ORN clinical trials and they will pursue their involvement through stakeholder panels along the project duration. Moreover, the collection of biopsies from patients will help us increase our knowledge about the pathology. Secondly, the combination of the biomaterial technology with the commercially available RGTA molecule would be of great interest in the field of bone regeneration. Third, the protection of the cells in this advanced-biomaterial could increase their lifespan in the microenvironment but interestingly, could also provide new perspectives on the uses of allogenic MSC facilitating their use in clinical trial.