Cell culture expansion media choice affects secretory, protective and immuno-modulatory features of adipose mesenchymal stromal cell-derived secretomes for orthopaedic applications Enrico Ragni, Andrea Papait, Michela Maria Taiana, Paola De Luca, Giulio Grieco, Elsa Vertua, Pietro Romele, Cecilia Colombo, Antonietta Rosa Silini, Ornella Parolini, Laura de Girolamo Regenerative Therapy, 2025 Mesenchymal stromal cells (MSCs) gained attention for their anti-inflammatory and trophic properties, with musculoskeletal diseases and osteoarthritis (OA) being among the most studied conditions. Alongside cells, their released factors and extracellular vesicles (EVs), overall termed “secretome”, are actively sifted being envisioned as the main therapeutic actors. In addition to standard supplementation given by foetal bovine serum (FBS) or human platelet lysate (hPL), new good manufacturing practice (GMP)-compliant serum/xeno (S/X)-free media formulations have been proposed, although their influence on MSCs phenotype and potential is scarcely described. The aim of this study is therefore to evaluate, in the OA context, the differences in secretome composition and potential after adipose-MSCs (ASCs) cultivation in both standard (FBS and hPL) and two next generation (S/X) GMP-ready supplements. Immunophenotype and secretory ability at soluble protein and EV-related levels, including embedded miRNAs, were analysed in the secretomes by means of flow cytometry, nanoparticle tracking analysis, high throughput ELISA and qRT-PCR arrays. Secretomes effect was tested in in vitro models of chondrocytes, lymphocytes and monocytes to mimic the OA microenvironment. Within a conserved molecular signature, a divergent fingerprint emerged for ASCs' secretomes collected after expansion in standard FBS/hPL or next-generation S/X formulations. Regarding soluble factors, a less protective feature for those in the secretome collected after ASCs were cultured in S/X media emerged. Moreover, the overall message for EV-miRNAs was characterized by a preponderance of protective signals in FBS and hPL conditions in a context of general safeguard given by ASCs released molecules. This dichotomy was reflected on secretomes’ potential in vitro , with expansion in hPL resulting in the most effective secretome for chondrocytes and in FBS for immune cells. These data open the question about the implications from using new media for MSCs expansion for clinical application. Although the undeniable advantages for GMP compliant processes, this study results suggest that new media formulations would deserve a deep characterization to drive the choice of the most effective one tailored to each specific application. • Divergent secretome signatures emerge from different MSC culture media. • EV-miRNAs after expansion in FBS/hPL promote protective signals for MSCs. • Secretomes after hPL are effective for chondrocytes and after FBS for immune cells. • Secretomes after serum/xeno media show less protective features for osteoarthritis. • Study emphasizes need for media characterization in clinical MSC/secretome use.
Comparative analysis of adipose-, bone marrow-, and amniotic membrane-derived MSC secretomes and EVs reveals shared and source-specific therapeutic signatures for osteoarthritis Enrico Ragni, Andrea Papait, Michela Maria Taiana, Paola De Luca, Giulio Grieco, Elsa Vertua, Pietro Romele, Antonietta Rosa Silini, Ornella Parolini, Laura de Girolamo Extracellular Vesicles and Circulating Nucleic Acids, 2025 Aim: Mesenchymal stromal cells (MSCs) exert their therapeutic effects in osteoarthritis (OA) primarily through paracrine signaling, including secreted proteins and extracellular vesicle (EV)-associated microRNAs (miRNAs). However, the contribution of tissue origin to the composition and function of these secretomes remains unclear. This study aimed to provide a comprehensive molecular and functional comparison of secretomes from adipose-derived (ASCs), bone marrow-derived MSCs (BMSCs) and human amniotic membrane-derived MSCs, with a specific focus on OA-relevant pathways. Methods: MSCs were immunophenotyped by flow cytometry. Secretomes were profiled for 200 factors and 784 EV-miRNAs. Functional enrichment was performed using Gene Ontology and Reactome databases. In vitro, secretomes were tested on interleukin (IL)-1β-stimulated human chondrocytes to assess modulation of OA-related gene expression. Results: All MSC secretomes shared a core of factors enriched in anti-inflammatory and matrix-regulatory functions. ASCs showed the differential expression of a few modulators, potentially shifting their chondroprotective phenotype. EV-miRNAs further distinguished the MSC types. ASCs and BMSCs clustered closely in both overall miRNA content and functional enrichment, which included pathways for extracellular matrix organization, angiogenesis and IL-6 signaling. BMSC- and ASC-EVs had a higher ratio of OA-protective to destructive miRNAs, including miR-24-3p, miR-125b-5p and miR-222-3p. Functional assays confirmed that all MSC secretomes were effective in suppressing key OA-related genes in inflamed chondrocytes, with ASCs and BMSCs having a stronger activity. Conclusion: These findings support the development of MSC-derived cell-free therapies and emphasize the importance of molecular profiling in MSC source selection. Further studies are warranted to validate these observations and optimize MSC-based interventions for clinical translation in OA.
Native characterization and QC profiling of human amniotic mesenchymal stromal cell vesicular fractions for secretome-based therapy Valentina Marassi, Giampiero La Rocca, Anna Placci, Alexandra Muntiu, Federica Vincenzoni, Alberto Vitali, Claudia Desiderio, Tullia Maraldi, Francesca Beretti, Eleonora Russo, Vitale Miceli, Pier Giulio Conaldi, Andrea Papait, Pietro Romele, Anna Cargnoni, Antonietta Rosa Silini, Francesco Alviano, Ornella Parolini, Stefano Giordani, Andrea Zattoni, Pierluigi Reschiglian, Barbara Roda Talanta, 2024 Human amniotic mesenchymal stromal cells (hAMSCs) have unique immunomodulatory properties making them attractive candidates for regenerative applications in inflammatory diseases. Most of their beneficial properties are mediated through their secretome. The bioactive factors concurring to its therapeutic activity are still unknown. Evidence suggests synergy between the two main components of the secretome, soluble factors and vesicular fractions, pivotal in shifting inflammation and promoting self-healing. Biological variability and the absence of quality control (QC) protocols hinder secretome-based therapy translation to clinical applications. Moreover, vesicular secretome contains a multitude of particles with varying size, cargos and functions whose complexity hinders full characterization and comprehension. This study achieved a significant advancement in secretome characterization by utilizing native, FFF-based separation and characterizing extracellular vesicles derived from hAMSCs. This was accomplished by obtaining dimensionally homogeneous fractions then characterized based on their protein content, potentially enabling the identification of subpopulations with diverse functionalities. This method proved to be successful as an independent technique for secretome profiling, with the potential to contribute to the standardization of a qualitative method. Additionally, it served as a preparative separation tool, streamlining populations before ELISA and LC-MS characterization. This approach facilitated the categorization of distinctive and recurring proteins, along with the identification of clusters associated with vesicle activity and functions. However, the presence of proteins unique to each fraction obtained through the FFF separation tool presents a challenge for further analysis of the protein content within these cargoes.
Disclosing the molecular profile of the human amniotic mesenchymal stromal cell secretome by filter-aided sample preparation proteomic characterization Alexandra Muntiu, Andrea Papait, Federica Vincenzoni, Alberto Vitali, Wanda Lattanzi, Pietro Romele, Anna Cargnoni, Antonietta Silini, Ornella Parolini, Claudia Desiderio Stem Cell Research and Therapy, 2023 Background The secretome of mesenchymal stromal cells isolated from the amniotic membrane (hAMSCs) has been extensively studied for its in vitro immunomodulatory activity as well as for the treatment of several preclinical models of immune-related disorders. The bioactive molecules within the hAMSCs secretome are capable of modulating the immune response and thus contribute to stimulating regenerative processes. At present, only a few studies have attempted to define the composition of the secretome, and several approaches, including multi-omics, are underway in an attempt to precisely define its composition and possibly identify key factors responsible for the therapeutic effect. Methods In this study, we characterized the protein composition of the hAMSCs secretome by a filter-aided sample preparation (FASP) digestion and liquid chromatography-high resolution mass spectrometry (LC–MS) approach. Data were processed for gene ontology classification and functional protein interaction analysis by bioinformatics tools. Results Proteomic analysis of the hAMSCs secretome resulted in the identification of 1521 total proteins, including 662 unique elements. A number of 157 elements, corresponding to 23.7%, were found as repeatedly characterizing the hAMSCs secretome, and those that resulted as significantly over-represented were involved in immunomodulation, hemostasis, development and remodeling of the extracellular matrix molecular pathways. Conclusions Overall, our characterization enriches the landscape of hAMSCs with new information that could enable a better understanding of the mechanisms of action underlying the therapeutic efficacy of the hAMSCs secretome while also providing a basis for its therapeutic translation.
Amniotic Membrane-Derived Stromal Cells Release Extracellular Vesicles That Favor Regeneration of Dystrophic Skeletal Muscles Martina Sandonà, Federica Esposito, Anna Cargnoni, Antonietta Silini, Pietro Romele, Ornella Parolini, Valentina Saccone International Journal of Molecular Sciences, 2023 Duchenne muscular dystrophy (DMD) is a muscle disease caused by mutations in the dystrophin gene characterized by myofiber fragility and progressive muscle degeneration. The genetic defect results in a reduced number of self-renewing muscle stem cells (MuSCs) and an impairment of their activation and differentiation, which lead to the exhaustion of skeletal muscle regeneration potential and muscle replacement by fibrotic and fatty tissue. In this study, we focused on an unexplored strategy to improve MuSC function and to preserve their niche based on the regenerative properties of mesenchymal stromal cells from the amniotic membrane (hAMSCs), that are multipotent cells recognized to have a role in tissue repair in different disease models. We demonstrate that the hAMSC secretome (CM hAMSC) and extracellular vesicles (EVs) isolated thereof directly stimulate the in vitro proliferation and differentiation of human myoblasts and mouse MuSC from dystrophic muscles. Furthermore, we demonstrate that hAMSC secreted factors modulate the muscle stem cell niche in dystrophic–mdx-mice. Interestingly, local injection of EV hAMSC in mdx muscles correlated with an increase in the number of activated Pax7+/Ki67+ MuSCs and in new fiber formation. EV hAMSCs also significantly reduced muscle collagen deposition, thus counteracting fibrosis and MuSCs exhaustion, two hallmarks of DMD. Herein for the first time we demonstrate that CM hAMSC and EVs derived thereof promote muscle regeneration by supporting proliferation and differentiation of resident muscle stem cells. These results pave the way for the development of a novel treatment to counteract DMD progression by reducing fibrosis and enhancing myogenesis in dystrophic muscles.
Comparison of EV-free fraction, EVs, and total secretome of amniotic mesenchymal stromal cells for their immunomodulatory potential: a translational perspective Andrea Papait, Enrico Ragni, Anna Cargnoni, Elsa Vertua, Pietro Romele, Alice Masserdotti, Carlotta Perucca Orfei, Patrizia Bonassi Signoroni, Marta Magatti, Antonietta R. Silini, Laura De Girolamo, Ornella Parolini Frontiers in Immunology, 2022 Amniotic mesenchymal stromal cells (hAMSCs) have unique immunomodulatory properties demonstrated in vitro and in vivo in various diseases in which the dysregulated immune system plays a major role. The immunomodulatory and pro-regenerative effects of MSCs, among which hAMSCs lie in the bioactive factors they secrete and in their paracrine activity, is well known. The mix of these factors (i.e., secretome) can be either freely secreted or conveyed by extracellular vesicles (EV), thus identifying two components in the cell secretome: EV-free and EV fractions. This study aimed to discern the relative impact of the individual components on the immunomodulatory action of the hAMSC secretome in order to obtain useful information for implementing future therapeutic approaches using immunomodulatory therapies based on the MSC secretome. To this aim, we isolated EVs from the hAMSC secretome (hAMSC-CM) by ultracentrifugation and validated the vesicular product according to the International Society for Extracellular Vesicles (ISEV) criteria. EVs were re-diluted in serum-free medium to maintain the EV concentration initially present in the original CM. We compared the effects of the EV-free and EV fractions with those exerted by hAMSC-CM in toto on the activation and differentiation of immune cell subpopulations belonging to both the innate and adaptive immune systems.We observed that the EV-free fraction, similar to hAMSC-CM in toto, a) decreases the proliferation of activated peripheral blood mononuclear cells (PBMC), b) reduces the polarization of T cells toward inflammatory Th subsets, and induces the induction of regulatory T cells; c) affects monocyte polarization to antigen-presenting cells fostering the acquisition of anti-inflammatory macrophage (M2) markers; and d) reduces the activation of B lymphocytes and their maturation to plasma cells. We observed instead that all investigated EV fractions, when used in the original concentrations, failed to exert any immunomodulatory effect, even though we show that EVs are internalized by various immune cells within PBMC. These findings suggest that the active component able to induce immune regulation, tested at original concentrations, of the hAMSC secretome resides in factors not conveyed in EVs. However, EVs isolated from hAMSC could exert actions on other cell types, as reported by others.
CM from intact hAM: an easily obtained product with relevant implications for translation in regenerative medicine Antonietta Rosa Silini, Andrea Papait, Anna Cargnoni, Elsa Vertua, Pietro Romele, Patrizia Bonassi Signoroni, Marta Magatti, Silvia De Munari, Alice Masserdotti, Anna Pasotti, Sara Rota Nodari, Giorgio Pagani, Mario Bignardi, Ornella Parolini Stem Cell Research and Therapy, 2021 Background It is now well established that factors (free or in extracellular vesicles) secreted by mesenchymal stromal cells (MSC) are important mediators of MSC regenerative actions. Herein we produced the secretome (conditioned medium, CM) from MSC isolated from the amniotic membrane (hAMSC) and CM from the intact amniotic membrane (hAM, no manipulation or enzymatic digestion) in order to potentially identify an effective, easy and less expensive secretome to produce for potential applications in regenerative medicine. Given that immunomodulation is a key mechanism of action through which hAMSC contributes to tissue regeneration, we used a comprehensive panel of in vitro immunomodulatory tests to compare the CMs. Methods Amniotic membranes were either cut into fragments or used for hAMSC isolation. CMs from hAMSC at passages 0 and 2 were collected after a standard 5-day culture while CM from hAM was collected after a 2- and 5-day culture. Immunomodulation was assessed in terms of PBMC and T-cell proliferation, T-cell subset polarization, T-regulatory cell induction, cell cytotoxicity and monocyte differentiation toward antigen-presenting cells. Furthermore, we performed a comparison between CM obtained from single donors and pooled CM. We also assessed the impact of lyophilization on the immunomodulatory properties of CM. Results We demonstrate that CM from hAM has comparable immunomodulatory properties to CM from hAMSC at passages 0 and 2. Furthermore, we demonstrate that pooled CMs have similar effects when compared to CM from single donors used separately. Finally, we demonstrate that lyophilization does not alter the in vitro immunomodulatory properties of CM from hAM and hAMSC. Conclusions The results presented herein support the possibility to produce secretome from intact hAM and open the prospect to highly improve the scalability of the GMP production process while reducing the costs and time related to the process of cell isolation and expansion. Moreover, the possibility of having a lyophilized secretome that maintains its original properties would allow for a ready-to-use product with easier handling, shipping and storage. The use of a lyophilized product will also facilitate clinicians by permitting customized reconstitution volumes and methods according to the most suitable formula required by the clinical application.
Human amniotic mesenchymal stromal cells support the ex vivo expansion of cord blood hematopoietic stem cells Valentina Orticelli, Andrea Papait, Elsa Vertua, Patrizia Bonassi Signoroni, Pietro Romele, Lorena Di Pietro, Marta Magatti, Luciana Teofili, Antonietta Rosa Silini, Ornella Parolini Stem Cells Translational Medicine, 2021 Currently, more than 30 000 allogeneic hematopoietic stem cell (HSC) transplantations have been performed for the treatment of hematological and nonhematological diseases using HSC from umbilical cord blood (CB). However, the wide utilization of CB as a source of HSC is limited by the low number of cells recovered. One strategy to expand ex vivo CB‐HSC is represented by the use of bone marrow mesenchymal stromal cells (BM‐MSCs) as a feeder to enhance HSC proliferation while maintaining HSC stemness. Indeed, BM‐MSCs have been recognized as one of the most relevant players in the HSC niche. Thus, it has been hypothesized that they can support the ex vivo expansion of HSC by mimicking the physiological microenvironment present in the hematopoietic niche. Due to the role of placenta in supporting fetal hematopoiesis, MSC derived from the amniotic membrane (hAMSC) of human term placenta could represent an interesting alternative to BM‐MSC as a feeder layer to enhance the proliferation and maintain HSC stemness. Therefore, in this study we investigated if hAMSC could support the ex vivo expansion of HSC and progenitor cells. The capacity of hAMSCs to support the ex vivo expansion of CB‐HSC was evaluated in comparison to the control condition represented by the CB‐CD34+ cells without a feeder layer. The coculture was performed at two different CD34+:MSC ratios (1:2 and 1:8) in both cell‐to‐cell contact and transwell setting. After 7 days, the cells were collected and analyzed for phenotype and functionality. Our results suggest that hAMSCs represent a valuable alternative to BM‐MSC to support: (a) the ex vivo expansion of CB‐HSC in both contact and transwell systems, (b) the colony forming unit ability, and (c) long‐term culture initiating cells ability. Overall, these findings may contribute to address the unmet need of high HSC content in CB units available for transplantation.
Protection of Brain Injury by Amniotic Mesenchymal Stromal Cell-Secreted Metabolites Francesca Pischiutta, Laura Brunelli, Pietro Romele, Antonietta Silini, Eliana Sammali, Lara Paracchini, Sergio Marchini, Laura Talamini, Paolo Bigini, Giorgio B. Boncoraglio, Roberta Pastorelli, Maria-Grazia De Simoni, Ornella Parolini, Elisa R. Zanier Critical Care Medicine, 2016
Internalization of nanopolymeric tracers does not alter characteristics of placental cells Paolo Bigini, Elisa R. Zanier, Silvia Saragozza, Simona Maciotta, Pietro Romele, Patrizia Bonassi Signoroni, Antonietta Silini, Francesca Pischiutta, Eliana Sammali, Claudia Balducci, Martina B. Violatto, Laura Talamini, David Garry, Davide Moscatelli, Raffaele Ferrari, Mario Salmona, Maria Grazia De Simoni, Federico Maggi, Giuseppe Simoni, Francesca Romana Grati, Ornella Parolini Journal of Cellular and Molecular Medicine, 2016
