Role of CD44 in increasing the potency of mesenchymal stem cell extracellular vesicles by hyaluronic acid in severe pneumonia

Li Zhou,Yoshifumi Naito,Che-Chung Yeh,Shinji Sugita,Hongli He,Qi Hao,Jae-Woo Lee

doi:10.1186/s13287-021-02329-2

Li Zhou, Yoshifumi Naito + Show 5 more

Open Access

https://doi.org/10.1186/s13287-021-02329-2

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Abstract

BackgroundAlthough promising, clinical translation of human mesenchymal stem or stromal cell-derived extracellular vesicles (MSC EV) for acute lung injury is potentially limited by significant production costs. The current study was performed to determine whether pretreatment of MSC EV with high molecular weight hyaluronic acid (HMW HA) would increase the therapeutic potency of MSC EV in severe bacterial pneumonia.MethodsIn vitro experiments were performed to determine the binding affinity of HMW HA to MSC EV and its uptake by human monocytes, and whether HMW HA primed MSC EV would increase bacterial phagocytosis by the monocytes. In addition, the role of CD44 receptor on MSC EV in the therapeutic effects of HMW HA primed MSC EV were investigated. In Pseudomonas aeruginosa (PA) pneumonia in mice, MSC EV primed with or without HMW HA were instilled intravenously 4 h after injury. After 24 h, the bronchoalveolar lavage fluid, blood, and lungs were analyzed for levels of bacteria, inflammation, MSC EV trafficking, and lung pathology.ResultsMSC EV bound preferentially to HMW HA at a molecular weight of 1.0 MDa compared with HA with a molecular weight of 40 KDa or 1.5 MDa. HMW HA primed MSC EV further increased MSC EV uptake and bacterial phagocytosis by monocytes compared to treatment with MSC EV alone. In PA pneumonia in mice, instillation of HMW HA primed MSC EV further reduced inflammation and decreased the bacterial load by enhancing the trafficking of MSC EV to the injured alveolus. CD44 siRNA pretreatment of MSC EV prior to incubation with HMW HA eliminated its trafficking to the alveolus and therapeutic effects.ConclusionsHMW HA primed MSC EV significantly increased the potency of MSC EV in PA pneumonia in part by enhancing the trafficking of MSC EV to the sites of inflammation via the CD44 receptor on MSC EV which was associated with increased antimicrobial activity.

Highlights

Promising, clinical translation of human mesenchymal stem or stromal cell-derived extracellular vesicles (MSC EV) for acute lung injury is potentially limited by significant production costs
Fluorescence microscopy showed that MSC EV bound preferentially to HMW Hyaluronic acid (HA) (1.0 MDa) compared with low molecular weight HA (LMW HA) (40 KDa) or, surprisingly, high molecular weight hyaluronic acid (HMW HA) (1.5 MDa) (Fig. 1b)
Incubation with MSC EV with HMW HA (1.0 MDa) significantly increased its uptake by human monocytes compared to MSC EV alone at doses between 0.2 and 5 μg/ml (Fig. 2a)

Summary

Introduction

Clinical translation of human mesenchymal stem or stromal cell-derived extracellular vesicles (MSC EV) for acute lung injury is potentially limited by significant production costs. Potential limitations of cell-based therapy exist such as the risk of iatrogenic tumor formation and the significant cost for cell storage in a bone marrow transplant facility, limiting the number of patients who may benefit. To overcome these obstacles, we recently demonstrated that human bone marrow-derived MSC extracellular vesicles (EV) shared similar therapeutic properties as MSC in treating ALI in small animal models as well as the ex vivo perfused human lung injured with bacterial pneumonia [8,9,10,11]. It is crucial to develop methods to increase the potency of MSC EV

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