TY - JOUR A1 - Müller-Deubert, Sigrid A1 - Seefried, Lothar A1 - Krug, Melanie A1 - Jakob, Franz A1 - Ebert, Regina T1 - Epidermal growth factor as a mechanosensitizer in human bone marrow stromal cells JF - Stem Cell Research N2 - Epidermal growth factors (EGFs) e.g. EGF, heparin-binding EGF and transforming growth factor alpha and their receptors e.g. EGFR and ErbB2 control proinflammatory signaling and modulate proliferation in bone marrow stromal cells (BMSC). Interleukin-6 and interleukin-8 are EGF targets and participate in the inflammatory phase of bone regeneration via non-canonical wnt signaling. BMSC differentiation is also influenced by mechanical strain-related activation of ERK1/2 and AP-1, but the role of EGFR signaling in mechanotransduction is unclear. We investigated the effects of EGFR signaling in telomerase-immortalized BMSC, transfected with a luciferase reporter, comprising a mechanoresponsive AP1 element, using ligands, neutralizing antibodies and EGFR inhibitors on mechanotransduction and we found that EGF via EGFR increased the response to mechanical strain. Results were confirmed by qPCR analysis of mechanoresponsive genes. EGF-responsive interleukin-6 and interleukin-8 were synergistically enhanced by EGF stimulation and mechanical strain. We show here in immortalized and primary BMSC that EGFR signaling enhances mechanotransduction, indicating that the EGF system is a mechanosensitizer in BMSC. Alterations in mechanosensitivity and -adaptation are contributors to age-related diseases like osteoporosis and the identification of a suitable mechanosensitizer could be beneficial. The role of the synergism of these signaling cascades in physiology and disease remains to be unraveled. KW - mechanotransduction KW - bone marrow stromal cells KW - epidermal growth factor KW - signaling Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170247 VL - 24 ER - TY - JOUR A1 - Ebert, Regina A1 - Weissenberger, Manuel A1 - Braun, Clemens A1 - Wagenbrenner, Mike A1 - Herrmann, Marietta A1 - Müller‐Deubert, Sigrid A1 - Krug, Melanie A1 - Jakob, Franz A1 - Rudert, Maximilian T1 - Impaired regenerative capacity and senescence‐associated secretory phenotype in mesenchymal stromal cells from samples of patients with aseptic joint arthroplasty loosening JF - Journal of Orthopaedic Research N2 - 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. KW - aseptic loosening KW - mesenchymal stromal cells KW - regenerative capacity KW - senescence‐associated secretory phenotype Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-238963 VL - 40 IS - 2 SP - 513 EP - 523 ER - TY - JOUR A1 - Ebert, Regina A1 - Benisch, Peggy A1 - Krug, Melanie A1 - Zeck, Sabine A1 - Meißner-Weigl, Jutta A1 - Steinert, Andre A1 - Rauner, Martina A1 - Hofbauer, Lorenz A1 - Jakob, Franz T1 - Acute phase serum amyloid A induces proinflammatory cytokines and mineralization via toll-like receptor 4 in mesenchymal stem cells JF - Stem Cell Research N2 - The role of serum amyloid A (SAA) proteins, which are ligands for toll-like receptors, was analyzed in human bone marrow-derived mesenchymal stem cells (hMSCs) and their osteogenic offspring with a focus on senescence, differentiation andmineralization. In vitro aged hMSC developed a senescence-associated secretory phenotype (SASP), resulting in enhanced SAA1/2, TLR2/4 and proinflammatory cytokine (IL6, IL8, IL1\(\beta\), CXCL1, CXCL2) expression before entering replicative senescence. Recombinant human SAA1 (rhSAA1) induced SASP-related genes and proteins in MSC, which could be abolished by cotreatment with the TLR4-inhibitor CLI-095. The same pattern of SASP-resembling genes was stimulated upon induction of osteogenic differentiation, which is accompanied by autocrine SAA1/2 expression. In this context additional rhSAA1 enhanced the SASP-like phenotype, accelerated the proinflammatory phase of osteogenic differentiation and enhanced mineralization. Autocrine/paracrine and rhSAA1 via TLR4 stimulate a proinflammatory phenotype that is both part of the early phase of osteogenic differentiation and the development of senescence. This signaling cascade is tightly involved in bone formation and mineralization, but may also propagate pathological extraosseous calcification conditions such as calcifying inflammation and atherosclerosis. KW - human atherosclerotic lesions KW - senescence KW - expression KW - toll-like receptor KW - mineralization KW - osteogenic differentiation KW - serum amyloid A KW - inflammation KW - mesenchymal stem cells KW - WNT5A KW - model KW - lines KW - stromal cells KW - RT-PCR Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148491 VL - 15 ER - TY - JOUR A1 - Benisch, Peggy A1 - Schilling, Tatjana A1 - Klein-Hitpass, Ludger A1 - Frey, Sönke P. A1 - Seefried, Lothar A1 - Raaijmakers, Nadja A1 - Krug, Melanie A1 - Regensburger, Martina A1 - Zeck, Sabine A1 - Schinke, Thorsten A1 - Amling, Michael A1 - Ebert, Amling A1 - Jakob, Franz T1 - The Transcriptional Profile of Mesenchymal Stem Cell Populations in Primary Osteoporosis Is Distinct and Shows Overexpression of Osteogenic Inhibitors JF - PLoS One N2 - Primary osteoporosis is an age-related disease characterized by an imbalance in bone homeostasis. While the resorptive aspect of the disease has been studied intensely, less is known about the anabolic part of the syndrome or presumptive deficiencies in bone regeneration. Multipotent mesenchymal stem cells (MSC) are the primary source of osteogenic regeneration. In the present study we aimed to unravel whether MSC biology is directly involved in the pathophysiology of the disease and therefore performed microarray analyses of hMSC of elderly patients (79-94 years old) suffering from osteoporosis (hMSC-OP). In comparison to age-matched controls we detected profound changes in the transcriptome in hMSC-OP, e.g. enhanced mRNA expression of known osteoporosis-associated genes (LRP5, RUNX2, COL1A1) and of genes involved in osteoclastogenesis (CSF1, PTH1R), but most notably of genes coding for inhibitors of WNT and BMP signaling, such as Sclerostin and MAB21L2. These candidate genes indicate intrinsic deficiencies in self-renewal and differentiation potential in osteoporotic stem cells. We also compared both hMSC-OP and non-osteoporotic hMSC-old of elderly donors to hMSC of similar to 30 years younger donors and found that the transcriptional changes acquired between the sixth and the ninth decade of life differed widely between osteoporotic and non-osteoporotic stem cells. In addition, we compared the osteoporotic transcriptome to long term-cultivated, senescent hMSC and detected some signs for pre-senescence in hMSC-OP. Our results suggest that in primary osteoporosis the transcriptomes of hMSC populations show distinct signatures and little overlap with non-osteoporotic aging, although we detected some hints for senescence-associated changes. While there are remarkable inter-individual variations as expected for polygenetic diseases, we could identify many susceptibility genes for osteoporosis known from genetic studies. We also found new candidates, e.g. MAB21L2, a novel repressor of BMP-induced transcription. Such transcriptional changes may reflect epigenetic changes, which are part of a specific osteoporosis-associated aging process. KW - alkaline-phosphatase KW - in vitro KW - bone-mineral density KW - age-related osteoporosis KW - WNT signaling pathway KW - replicative senescence KW - morphogenetic protein KW - parathyroid-hormone KW - growth factor KW - skeletal overexpression Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133379 VL - 7 IS - 9 ER -