@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{EbertWeissenbergerBraunetal.2022,
  author    = {Ebert, Regina and Weissenberger, Manuel and Braun, Clemens and Wagenbrenner, Mike and Herrmann, Marietta and M{\"u}ller-Deubert, Sigrid and Krug, Melanie and Jakob, Franz and Rudert, Maximilian},
  title     = {Impaired regenerative capacity and senescence-associated secretory phenotype in mesenchymal stromal cells from samples of patients with aseptic joint arthroplasty loosening},
  series = {Journal of Orthopaedic Research},
  volume    = {40},
  journal   = {Journal of Orthopaedic Research},
  number    = {2},
  doi       = {10.1002/jor.25041},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-238963},
  pages     = {513 -- 523},
  year      = {2022},
  abstract  = {Aseptic loosening of total hip and knee joint replacements is the most common indication for revision surgery after primary hip and knee arthroplasty. Research suggests that exposure and uptake of wear by mesenchymal stromal cells (MSC) and macrophages results in the secretion of proinflammatory cytokines and local osteolysis, but also impaired cell viability and regenerative capacity of MSC. Therefore, this in vitro study compared the regenerative and differentiation capacity of MSC derived from patients undergoing primary total hip arthroplasty (MSCprim) to MSC derived from patients undergoing revision surgery after aseptic loosening of total hip and knee joint implants (MSCrev). Regenerative capacity was examined by measuring the cumulative population doubling (CPD) in addition to the number of passages until cells stopped proliferating. Osteogenesis and adipogenesis in monolayer cultures were assessed using histological stainings. Furthermore, RT-PCR was performed to evaluate the relative expression of osteogenic and adipogenic marker genes as well as the expression of markers for a senescence-associated secretory phenotype (SASP). MSCrev possessed a limited regenerative capacity in comparison to MSCprim. Interestingly, MSCrev also showed an impaired osteogenic and adipogenic differentiation capacity compared to MSCprim and displayed a SASP early after isolation. Whether this is the cause or the consequence of the aseptic loosening of total joint implants remains unclear. Future research should focus on the identification of specific cell markers on MSCprim, which may influence complication rates such as aseptic loosening of total joint arthroplasty to further individualize and optimize total joint arthroplasty.},
  language  = {en}
}
@article{KleinBenchellalKleffetal.2013,
  author    = {Klein, Diana and Benchellal, Mohamed and Kleff, Veronika and Jakob, Heinz G{\"u}nther and Erg{\"u}n, S{\"u}leyman},
  title     = {Hox genes are involved in vascular wall-resident multipotent stem cell differentiation into smooth muscle cells},
  series = {Scientific Reports},
  volume    = {3},
  journal   = {Scientific Reports},
  number    = {2178},
  doi       = {10.1038/srep02178},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131496},
  year      = {2013},
  abstract  = {Human vascular wall-resident CD44+ multipotent stem cells (VW-MPSCs) within the vascular adventitia are capable to differentiate into pericytes and smooth muscle cells (SMC). This study demonstrates HOX-dependent differentiation of CD44(+) VW-MPSCs into SMC that involves epigenetic modification of transgelin as a down-stream regulated gene. First, HOXB7, HOXC6 and HOXC8 were identified to be differentially expressed in VW-MPSCs as compared to terminal differentiated human aortic SMC, endothelial cells and undifferentiated pluripotent embryonic stem cells. Silencing these HOX genes in VW-MPSCs significantly reduced their sprouting capacity and increased expression of the SMC markers transgelin and calponin and the histone gene histone H1. Furthermore, the methylation pattern of the TAGLN promoter was altered. In summary, our findings suggest a role for certain HOX genes in regulating differentiation of human VW-MPSC into SMCs that involves epigenetic mechanisms. This is critical for understanding VW-MPSC-dependent vascular disease processes such as neointima formation and tumor vascularization.},
  language  = {en}
}