Elsevier

Life Sciences

Volume 308, 1 November 2022, 120990
Life Sciences

Review article
Analysis of MSCs' secretome and EVs cargo: Evaluation of functions and applications

https://doi.org/10.1016/j.lfs.2022.120990Get rights and content

Abstract

Mesenchymal stem cells (MSCs) can exert different functions and can be used in several medical fields. In the last years, MSC properties have been attributed to their secreted factors such as soluble proteins, cytokines and growth factors. Moreover, a key role is played by the extracellular vesicles (EVs) which lead a heterogeneous cargo of proteins, lipids and small and long non-coding RNAs that interfere with the pathways of the recipient cells. Due to the safeness and easiness in obtaining the secretome, its use is becoming a turning point for the application in physiological and pathological fields. This review summarizes the most recent studies on the use of MSCs secretome, focusing on some physiological (angiogenesis and osteogenesis) and pathological (cancer, cardiovascular and autoimmune diseases) applications. The secreted analyzed factors are listed in a table. In addition, the different characteristics of the fetal MSCs derived secretome and the differences in the secretome composition of three-dimensionally (3D) cultured cells are discussed. As very innovative aspects, recent studies on some applications of engineered vesicles, embedded or not in three-dimensional structures, are treated and the influence of some epigenetic modifications on cells and EVs is investigated.

Introduction

Mesenchymal stem cells (MSCs) are multipotent and undifferentiated cells with the ability to differentiate into several mesenchymal lineages such as osteoblasts, chondrocytes, adipocytes, myocytes [1], [2] and also neuron-like [3]. Although it is known that MSCs are responsible of several cell functions, such as pro-angiogenesis [4], anti-apoptosis [5], neuro-protection and regulation [6], anti-inflammation [7], immunomodulation [8] and others, several studies showed that these functions are mainly exerted by MSCs secreted paracrine factors [9], [10], [11], [12], [13].

In fact, cells need to communicate between each other and to exchange information not only through a direct cell-cell interaction but also through an indirect way as the endocrine, autocrine and paracrine signalling [14]. In particular, paracrine signalling can occur through a set of soluble factors and/or extracellular vesicles (EVs) secreted by the cells in the culture medium, called ‘conditioned medium’. The set of secreted factors with EVs is called ‘secretome’.

Amongst the main components of the soluble fraction, there are proteins, cytokines, chemokines and growth factors [15], whilst EVs are distinguished into exosomes, microvesicles (MVs) and apoptotic bodies, according to their size and biogenesis. About that, exosomes are 30–150 nm in size and derive by multivesicular bodies generated by the early endosomes, whilst microvesicles are 100–1000 nm in size and derive by plasma membrane shedding. Both of them are enriched in small and long non-coding RNAs, mRNAs, lipid and proteins which exert specific functions in the recipient cells [16], [17]. Finally, apoptotic bodies are 1–3 μm in size and derive from apoptotic cells that disassemble themselves and close their content into vesicles, protecting the neighbouring cells. They contain cytosolic fragments and proteins as well as nuclear fragments, such as DNA and histones, or even organelles [18], [19].

It has been proved that the secretome has a higher safety profile if compared to cell engrafting due to its reduced possibility of neoplastic transformation [20] and a better ease of storage with the use of natural and non-toxic agents such as the trehalose, a natural disaccharide found in many foods [21]. Moreover, in the last few years, the analysis of factors contained in the secretome and/or extracellular vesicles made possible for researchers to engineer EVs for a controlled drug delivery [22], [23], [24], [25] or also to defeat viruses [26] but also to evaluate the risks and/or benefits of exposure to certain substances (e.g., chemical agents, environmental pollutants, etc.) [27], [28].

This review aims to summarize current literature on secretome derived from different MSCs with the purpose of creating a compendium of the most recently discovered proteins and non-coding RNAs as components of the soluble fraction or EVs.

Starting from these goals, the applications of the secretome from MSCs from different sources, analyzed in its totality or in its specific components, have been characterized in a broad range of physiological and pathological conditions both in in vitro and in vivo studies.

Section snippets

Angiogenesis

Tissue and organ regeneration is nowadays a field of interest for many worldwide researchers. Although cell applications, together or not with a scaffold, were interestingly investigated [29], [30], [31], [32], [33], recently the attention was focused on the cells released paracrine factors and their regenerative properties. For example, studies concerning the secretome characterization from bone marrow MSCs (BM-MSCs) showed that the highest percentage of secreted proteins were involved in cell

Cancer

Cancer diseases are nowadays amongst the most diffused and lethal diseases in the world. Moreover, several studies predicted an increase in the number of affected people by 2040 [59], [60]; thus, it can be important to identify new tumor markers as well as to characterize cancer cells secretome to provide a tool to target specific cancer pathways. In this regard, several studies analyzed the secretome of cancer cells to find some specific factors that could be considered as biomarkers of

Cardiovascular diseases

Cardiovascular diseases (CVDs) are heart and circulatory system disorders with an extremely high incidence. CVDs are classified as chronic diseases and evolve gradually over a lifetime, generating numerous symptoms in the patients. They can also lead to sudden death. EVs seem to be excellent candidates for the treatment of myocardial damage, as shown by some recent studies. The treatment with MSC-EVs by hypoxic cardiomyocytes caused a marked improvement in cell invasion, proliferation and

Autoimmune diseases

Autoimmune diseases are characterized by a misreaction of the immune system, which attacks and destroys healthy tissues in the body by mistakenly recognizing them as foreign. These disorders are multifaceted and the causes are not entirely clear but several external factors seem to play a role. Recently, it was discovered that EVs derived from mesenchymal stem cells play a role in the progression or otherwise of the disease. In this regard, over-expressing programmed cell death-ligand

Characterization of secretome from fetal MSCs

Several studies have already proved that there are important differences amongst adult and fetal MSCs. Indeed, fetal MSCs showed better abilities as immune-modulators [79] and are more proliferative with longer telomeres and less predestined, with an higher expression of the pluripotency markers than adult ones [80], [81]. Moreover, they showed enhanced neuroprotective abilities also in in vivo models [82].

Due to the differences in the cell properties at different stages of life, it was easy to

Analysis of secretome from 3D cultured MSCs

Several scientific studies proved that cells cultured under 3D conditions were able to better mimic the properties of their native tissues [87], [88] both in oncological and regenerative studies. In this last field, until ten years ago, mesenchymal stem cells were only cultured in 2D adhesion conditions. Recently, several studies were performed on 3D cultures, demonstrating their effective superiority. Although to date there is still no standardized technique to obtain 3D spheroids, many

Secretome and epigenetic modifications

In recent years, science has focused much of its interest on studying the environmental effects on cells. The outdoor and indoor air pollution is amongst the increasingly significant issues, resulting in the death of more than 6 millions of people [100]. Moreover, the exposure to chemical compounds (for example phthalates and phenols, perfluorinated chemicals, ethyl paraben) as well as ionizing radiations, metals or cigarette smoke, lead cells to side effects [101]. It was already known that

Conclusion

Mesenchymal stem cells are multipotent cells with different functions [1], [2], [3]. Recently, several studies attributed these abilities to their secreted factors that act in a paracrine manner on the neighbouring cells [9], [10], [11], [12], [13]. In fact, paracrine signalling happens through the so-called “secretome”, formed by soluble factors, released by the cells in the culture medium, and extracellular vesicles (EVs), which are vehicles of small and long non-coding RNAs, proteins and

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data availability

No data was used for the research described in the article.

CRediT authorship contribution statement

Valentina Urrata: Conceptualization, Writing – original draft, Writing – review & editing. Marco Trapani: Writing – original draft. Mara Franza: Writing – original draft. Francesco Moschella: Supervision, Writing – review & editing. Anna Barbara Di Stefano: Conceptualization, Supervision, Writing – original draft, Writing – review & editing. Francesca Toia: Supervision, Writing – review & editing.

Declaration of competing interest

The authors declare that there are no conflicts of interest.

Acknowledgements

Valentina Urrata, PhDst is supported, for this research, by the University of Palermo (IT), Doctoral Course of Experimental Oncology and Surgery, Cycle XXXVI.

References (105)

  • S. Ren et al.

    miR-29a-3p transferred by mesenchymal stem cells-derived extracellular vesicles protects against myocardial injury after severe acute pancreatitis

    Life Sci.

    (2021)
  • T. Shigemoto-Kuroda et al.

    MSC-derived extracellular vesicles attenuate immune responses in two autoimmune murine models: type 1 diabetes and uveoretinitis

    Stem Cell Rep.

    (2017)
  • J. Xu et al.

    Human fetal mesenchymal stem cell secretome enhances bone consolidation in distraction osteogenesis

    Stem Cell Res Ther

    (2016)
  • K. Carter et al.

    Characterizing the impact of 2D and 3D culture conditions on the therapeutic effects of human mesenchymal stem cell secretome on corneal wound healing in vitro and ex vivo

    Acta Biomater.

    (2019)
  • C. Chen et al.

    3D printed collagen/silk fibroin scaffolds carrying the secretome of human umbilical mesenchymal stem cells ameliorated neurological dysfunction after spinal cord injury in rats

    Regen. Biomater.

    (2022)
  • A.A. Khan et al.

    Significant transcriptomic changes are associated with differentiation of bone marrow-derived mesenchymal stem cells into neural progenitor-like cells in the presence of bFGF and EGF

    Cell Biosci.

    (2020)
  • M.F. Pittenger et al.

    Multilineage potential of adult human mesenchymal stem cells

    Science

    (1999)
  • K.S. Bae et al.

    Neuron-like differentiation of bone marrow-derived mesenchymal stem cells

    Yonsei Med. J.

    (2011)
  • W.H. Huang et al.

    Mesenchymal stem cells promote growth and angiogenesis of tumors in mice

    Oncogene

    (2013)
  • J. Kossl et al.

    Antiapoptotic properties of mesenchymal stem cells in a mouse model of corneal inflammation

    Stem Cells Dev.

    (2021)
  • I. Papazian et al.

    Mesenchymal stem cell protection of neurons against glutamate excitotoxicity involves reduction of NMDA-triggered calcium responses and surface GluR1, and is partly mediated by TNF

    Int. J. Mol. Sci.

    (2018)
  • A.R.R. Weiss et al.

    Immunomodulation by Mesenchymal Stem Cells (MSCs): mechanisms of action of living, apoptotic, and dead MSCs

    Front. Immunol.

    (2019)
  • L. Chen et al.

    Paracrine factors of mesenchymal stem cells recruit macrophages and endothelial lineage cells and enhance wound healing

    PLoS One

    (2008)
  • W. Huang et al.

    Paracrine factors secreted by MSCs promote astrocyte survival associated with GFAP downregulation after ischemic stroke via p38 MAPK and JNK

    J. Cell. Physiol.

    (2015)
  • P. Kuchroo et al.

    Paracrine factors secreted by umbilical cord-derived mesenchymal stem cells induce angiogenesis in vitro by a VEGF-independent pathway

    Stem Cells Dev.

    (2015)
  • D. Pankajakshan et al.

    Mesenchymal stem cell paracrine factors in vascular repair and regeneration

    J. Biomed. Technol. Res.

    (2014)
  • J. Driscoll et al.

    The mesenchymal stem cell secretome as an acellular regenerative therapy for liver disease

    J. Gastroenterol.

    (2019)
  • F.T. Borges et al.

    Extracellular vesicles: structure, function, and potential clinical uses in renal diseases

    Braz. J. Med. Biol. Res.

    (2013)
  • X. Zhou et al.

    The function and clinical application of extracellular vesicles in innate immune regulation

    Cell Mol Immunol.

    (2020)
  • M. Battistelli et al.

    Apoptotic bodies: particular extracellular vesicles involved in intercellular communication

    Biology (Basel)

    (2020)
  • Y.B. Haddad et al.

    Sterile inflammation of endothelial cell-derived apoptotic bodies is mediated by interleukin-1α

    PNAS

    (2011)
  • C. Théry et al.

    Minimal information for studies of extracellular vesicles 2018 (MISEV2018): a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

    J. Extracell Vesicles

    (2018)
  • A. Jeyaram et al.

    Preservation and storage stability of extracellular vesicles for therapeutic applications

    AAPS J.

    (2017)
  • L. Huang et al.

    Engineered exosomes as an in situ DC-primed vaccine to boost antitumor immunity in breast cancer

    Mol. Cancer

    (2022)
  • B. Hui et al.

    Engineered exosomes for co-delivery of PGM5-AS1 and oxaliplatin to reverse drug resistance in colon cancer

    J. Cell. Physiol.

    (2022)
  • G. Liang et al.

    Engineered exosomes for targeted co-delivery of miR-21 inhibitor and chemotherapeutics to reverse drug resistance in colon cancer

    J. Nanobiotechnol.

    (2020)
  • A. Nikhil et al.

    Evaluating potential of tissue-engineered cryogels and chondrocyte derived exosomes in articular cartilage repair

    Biotechnol. Bioeng.

    (2022)
  • S. Shrivastava et al.

    Exosome-mediated stable epigenetic repression of HIV-1

    Nat. Commun.

    (2021)
  • K. Man et al.

    Epigenetic reprogramming enhances the therapeutic efficacy of osteoblast-derived extracellular vesicles to promote human bone marrow stem cell osteogenic differentiation

    J. Extracell Vesicles

    (2021)
  • J. Zou et al.

    Ethanol induces secretion of proinflammatory extracellular vesicles that inhibit adult hippocampal neurogenesis through G9a/GLP-epigenetic signaling

    Front. Immunol.

    (2022)
  • C. Amnael Orozco-Díaz et al.

    Characterization of a composite polylactic acid-hydroxyapatite 3D-printing filament for bone-regeneration

    Biomed. Phys. Eng. Express

    (2020)
  • G.G. Walmsley et al.

    Stem cells in bone regeneration

    Stem Cell Rev. Rep.

    (2016)
  • Y. Xiao et al.

    Clonal characterization of bone marrow derived stem cells and their application for bone regeneration

    Int. J. Oral Sci.

    (2010)
  • S.R. Baglio et al.

    Human bone marrow- and adipose-mesenchymal stem cells secrete exosomes enriched in distinctive miRNA and tRNA species

    Stem Cell Res Ther

    (2015)
  • Y. Lu et al.

    Extracellular vesicle-enclosed miR-486-5p mediates wound healing with adipose-derived stem cells by promoting angiogenesis

    J. Cell. Mol. Med.

    (2020)
  • T. Kang et al.

    Adipose-derived stem cells induce angiogenesis via microvesicle transport of miRNA-31

    Stem Cells Transl. Med.

    (2016)
  • Y.H. Oktaviono et al.

    Human umbilical cord blood-mesenchymal stem cell-derived secretome in combination with atorvastatin enhances endothelial progenitor cells proliferation and migration

    F1000Research

    (2021)
  • A. Ratushnyy et al.

    Secretome of senescent adipose-derived mesenchymal stem cells negatively regulates angiogenesis

    Int. J. Mol. Sci.

    (2020)
  • J. Boulestreau et al.

    Mesenchymal stem cell derived extracellular vesicles in aging

    Front. Cell Dev. Biol.

    (2020)
  • S. Bianciardi et al.

    Vescicole extracellulari e metabolismo Osseo: ruolo e possibili implicazioni cliniche

    L’Endocrinologo

    (2021)
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