@article{TrivanovicVolkmannStoeckletal.2023,
  author    = {Trivanovic, Drenka and Volkmann, Noah and Stoeckl, Magdalena and Tertel, Tobias and Rudert, Maximilian and Giebel, Bernd and Herrmann, Marietta},
  title     = {Enhancement of immunosuppressive activity of mesenchymal stromal cells by platelet-derived factors is accompanied by apoptotic priming},
  series = {Stem Cell Reviews and Reports},
  volume    = {19},
  journal   = {Stem Cell Reviews and Reports},
  number    = {3},
  doi       = {10.1007/s12015-022-10471-4},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324669},
  pages     = {713-733},
  year      = {2023},
  abstract  = {The pro-inflammatory phase of bone healing, initiated by platelet activation and eventually hematoma formation, impacts bone marrow mesenchymal stromal cells (MSCs) in unknown ways. Here, we created platelet-rich plasma (PRP) hydrogels to study how platelet-derived factors modulate functional properties of encapsulated MSCs in comparison to a non-inflammatory fibrin (FBR) hydrogel environment. MSCs were isolated from human bone marrow, while PRP was collected from pooled apheresis thrombocyte concentrates and used for hydrogel preparation. After their encapsulation in hydrogels for 72 h, retrieved MSCs were analyzed for immunomodulatory activities, apoptosis, stem cell properties, senescence, CD9\(^+\), CD63\(^+\) and CD81\(^+\) extracellular vesicle (EV) release, and metabolism-related changes. PRP-hydrogels stimulated immunosuppressive functions of MSCs, along with their upregulated susceptibility to cell death in communication with PBMCs and augmented caspase 3/7 activity. We found impaired clonal growth and cell cycle progression, and more pronounced β-galactosidase activity as well as accumulation of LC3-II-positive vacuoles in PRP-MSCs. Stimuli derived from PRP-hydrogels upregulated AKT and reduced mTOR phosphorylation in MSCs, which suggests an initiation of survival-related processes. Our results showed that PRP-hydrogels might represent a metabolically stressful environment, inducing acidification of MSCs, reducing polarization of the mitochondrial membrane and increasing lipid accumulation. These features were not detected in FBR-MSCs, which showed reduced CD63\(^+\) and CD81\(^+\) EV production and maintained clonogenicity. Our data revealed that PRP-derived hematoma components cause metabolic adaptation of MSCs followed by increased immune regulatory functions. For the first time, we showed that PRP stimuli represent a survival challenge and "apoptotic priming" that are detrimental for stem cell-like growth of MSCs and important for their therapeutic consideration.},
  language  = {en}
}
@article{WangStoecklLietal.2022,
  author    = {Wang, Chenglong and St{\"o}ckl, Sabine and Li, Shushan and Herrmann, Marietta and Lukas, Christoph and Reinders, Yvonne and Sickmann, Albert and Gr{\"a}ssel, Susanne},
  title     = {Effects of extracellular vesicles from osteogenic differentiated human BMSCs on osteogenic and adipogenic differentiation capacity of na{\"i}ve human BMSCs},
  series = {Cells},
  volume    = {11},
  journal   = {Cells},
  number    = {16},
  issn      = {2073-4409},
  doi       = {10.3390/cells11162491},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-286112},
  year      = {2022},
  abstract  = {Osteoporosis, or steroid-induced osteonecrosis of the hip, is accompanied by increased bone marrow adipogenesis. Such a disorder of adipogenic/osteogenic differentiation, affecting bone-marrow-derived mesenchymal stem cells (BMSCs), contributes to bone loss during aging. Here, we investigated the effects of extracellular vesicles (EVs) isolated from human (h)BMSCs during different stages of osteogenic differentiation on the osteogenic and adipogenic differentiation capacity of na{\"i}ve (undifferentiated) hBMSCs. We observed that all EV groups increased viability and proliferation capacity and suppressed the apoptosis of na{\"i}ve hBMSCs. In particular, EVs derived from hBMSCs at late-stage osteogenic differentiation promoted the osteogenic potential of na{\"i}ve hBMSCs more effectively than EVs derived from na{\"i}ve hBMSCs (na{\"i}ve EVs), as indicated by the increased gene expression of COL1A1 and OPN. In contrast, the adipogenic differentiation capacity of na{\"i}ve hBMSCs was inhibited by treatment with EVs from osteogenic differentiated hBMSCs. Proteomic analysis revealed that osteogenic EVs and na{\"i}ve EVs contained distinct protein profiles, with pro-osteogenic and anti-adipogenic proteins encapsulated in osteogenic EVs. We speculate that osteogenic EVs could serve as an intercellular communication system between bone- and bone-marrow adipose tissue, for transporting osteogenic factors and thus favoring pro-osteogenic processes. Our data may support the theory of an endocrine circuit with the skeleton functioning as a ductless gland.},
  language  = {en}
}
@article{HerrmannDiederichsMelniketal.2021,
  author    = {Herrmann, Marietta and Diederichs, Solvig and Melnik, Svitlana and Riegger, Jana and Trivanović, Drenka and Li, Shushan and Jenei-Lanzl, Zsuzsa and Brenner, Rolf E. and Huber-Lang, Markus and Zaucke, Frank and Schildberg, Frank A. and Gr{\"a}ssel, Susanne},
  title     = {Extracellular Vesicles in Musculoskeletal Pathologies and Regeneration},
  series = {Frontiers in Bioengineering and Biotechnology},
  volume    = {8},
  journal   = {Frontiers in Bioengineering and Biotechnology},
  issn      = {2296-4185},
  doi       = {10.3389/fbioe.2020.624096},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-222882},
  year      = {2021},
  abstract  = {The incidence of musculoskeletal diseases is steadily increasing with aging of the population. In the past years, extracellular vesicles (EVs) have gained attention in musculoskeletal research. EVs have been associated with various musculoskeletal pathologies as well as suggested as treatment option. EVs play a pivotal role in communication between cells and their environment. Thereby, the EV cargo is highly dependent on their cellular origin. In this review, we summarize putative mechanisms by which EVs can contribute to musculoskeletal tissue homeostasis, regeneration and disease, in particular matrix remodeling and mineralization, pro-angiogenic effects and immunomodulatory activities. Mesenchymal stromal cells (MSCs) present the most frequently used cell source for EV generation for musculoskeletal applications, and herein we discuss how the MSC phenotype can influence the cargo and thus the regenerative potential of EVs. Induced pluripotent stem cell-derived mesenchymal progenitor cells (iMPs) may overcome current limitations of MSCs, and iMP-derived EVs are discussed as an alternative strategy. In the last part of the article, we focus on therapeutic applications of EVs and discuss both practical considerations for EV production and the current state of EV-based therapies.},
  language  = {en}
}