Monica Romero Lopez

All Publications

• Osteogenic ability of rat bone marrow concentrate is at least as efficacious as mesenchymal stem cells in vitro. Journal of biomedical materials research. Part B, Applied biomaterials Kohno, Y., Lin, T., Pajarinen, J., Romero-Lopez, M., Maruyama, M., Huang, J., Nathan, K., Yao, Z., Goodman, S. B. 2019

  Abstract

  Cell therapy using bone marrow concentrate (BMC) or purified and expanded mesenchymal stem cells (MSCs) has been shown to have a promising osteogenic capacity. However, few studies have directly compared their relative osteogenic ability. The aim of this study was to compare the osteogenic ability of BMC isolated by density gradient centrifugation with bone marrow-derived MSCs in vitro using the cells of 3-month-old Sprague-Dawley rats. The isolated cells were seeded onto 24-well plates (1*105 cells/well) and cultured in control growth media, osteogenic media with dexamethasone, or media without dexamethasone (which simulated the in vivo tissue environment). Alkaline phosphatase activity at week 2, osteocalcin using quantitative real-time polymerase chain reaction at week 4, and Alizarin red staining at week 4 were evaluated. In the osteogenic media with dexamethasone, BMC showed equivalent (osteocalcin) or even greater (Alizarin red staining) osteogenic ability compared to MSCs, suggesting that cross-talk among various cells in the BMC leads to greater osteogenesis. Furthermore, in the osteogenic media without dexamethasone, BMC showed equivalent (osteocalcin) or a trend for greater (Alizarin red staining) bone formation than MSCs alone. Our results suggest that BMC has at least comparable bone regeneration potential to MSCs. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: 00B: 000-000, 2019.

  View details for PubMedID 30779478

• Preconditioned or IL4-Secreting Mesenchymal Stem Cells Enhanced Osteogenesis at Different Stages. Tissue engineering. Part A Lin, T., Kohno, Y., Huang, J., Romero-Lopez, M., Maruyama, M., Ueno, M., Pajarinen, J., Nathan, K., Yao, Z., Yang, F., Wu, J., Goodman, S. B. 2019

  Abstract

  Chronic inflammation-associated bone diseases involve continuous destruction and impaired regeneration of bone. Mesenchymal stem cell (MSC)-based therapy has great potential to modulate inflammatory responses and enhance tissue regeneration. We previously showed that lipopolysaccharide [LPS] plus TNF preconditioned MSCs or genetically modified inflammation-sensing (driven by NFB activation) IL4-secreting MSCs enhanced immunomodulation of macrophages to the more desired tissue repaired M2 type. In the current study, the paracrine regulation of therapeutic MSCs on the pro-inflammatory response and osteogenesis of macrophage-MSC co-cultures (representing endogenous cells) was examined using an in vitro transwell system. In the co-cultures, IL4-secreting MSCs decreased TNF and iNOS expression, and increased Arginase 1 and CD206 expression in the presence of LPS-contaminated polyethylene particles. The preconditioned MSCs decreased TNF and CD206 expression in the bottom MSC-macrophage co-cultures in the presence of contaminated particles. In osteogenesis assays, IL4-secreting MSCs decreased ALP expression, but increased alizarin red staining in the presence of contaminated particles. The preconditioned MSCs increased ALP and osteocalcin expression, and had no significant effect on alizarin red staining. These results suggest that potential treatments using preconditioned MSCs at an earlier stage, or IL4-secreting MSCs at a later stage could enhance bone regeneration in inflammatory conditions including periprosthetic osteolysis.

  View details for PubMedID 30652628

• Trained murine mesenchymal stem cells have anti-inflammatory effect on macrophages, but defective regulation on T-cell proliferation. FASEB journal : official publication of the Federation of American Societies for Experimental Biology Lin, T., Pajarinen, J., Kohno, Y., Huang, J., Maruyama, M., Romero-Lopez, M., Nathan, K., Yao, Z., Goodman, S. B. 2018: fj201801845R

  Abstract

  Mesenchymal stem cell (MSC)-mediated immunomodulation affects both innate and adaptive immune systems. These responses to environmental cues, such as pathogen-associated molecular patterns, damage-associated molecular patterns, or proinflammatory cytokines, are crucial for resolution of inflammation, as well as successful tissue healing and regeneration. We observed that intermittent, repeated exposure of MSCs to LPS induced stronger NF-kappaB activation than singular stimulation. A similar phenomenon, named innate immune memory or trained immunity, has been reported with macrophages. However, the potential regulation of "immune memory" in nonclassic immune cells, such as MSCs, has not been reported. In the current study, we chose IFN-gamma plus TNF-alpha restimulation-induced iNOS expression as a model of MSC activation, because IFN-gamma and TNF-alpha play crucial roles in MSC-mediated immunomodulation. The iNOS expression was enhanced in LPS-trained MSCs, 3 d after a washout period following primary stimulation. LPS-trained MSCs enhanced the anti-inflammatory (arginase 1 and CD206) marker expression, but decreased the proinflammatory marker (TNF-alpha, IL-1beta, iNOS, and IL-6) expression using an MSC-macrophage coculture model. In contrast, LPS-trained MSCs demonstrated a defective regulation on CD4 T-cell proliferation. Mechanistic studies suggested that histone methylation and the JNK pathway are involved in LPS-trained immunomodulation in MSCs. Our results demonstrate differential immunomodulatory effects of trained MSCs on macrophages and T cells. These immunomodulatory consequences are critical, because they will have a major impact on current MSC-based cell therapies.-Lin, T., Pajarinen, J., Kohno, Y., Huang, J.-F., Maruyama, M., Romero-Lopez, M., Nathan, K., Yao, Z., Goodman, S. B. Trained murine mesenchymal stem cells have anti-inflammatory effect on macrophages, but defective regulation on T-cell proliferation.

  View details for PubMedID 30521384

• NFkappaB sensing IL-4 secreting mesenchymal stem cells mitigate the proinflammatory response of macrophages exposed to polyethylene wear particles. Journal of biomedical materials research. Part A Lin, T., Kohno, Y., Huang, J., Romero-Lopez, M., Pajarinen, J., Maruyama, M., Nathan, K., Yao, Z., Goodman, S. B. 2018

  Abstract

  Total joint replacement is a highly effective treatment for patients with end-stage arthritis. Proinflammatory macrophages (M1) mediate wear particle-associated inflammation and bone loss. Anti-inflammatory macrophages (M2) help resolve tissue damage and favor bone regeneration. Mesenchymal stem cell (MSC)-based therapy mitigates the M1 dominated inflammatory reaction and favorably modulates the bone remodeling process. In the current study, the immunomodulating ability of (1) unmodified MSCs, (2) MSCs preconditioned by NFkappaB stimulating ligands [lipopolysaccharide (LPS) plus TNFalpha], and (3) genetically modified MSCs that secrete IL-4 as a response to NFkappaB activation (NFkappaB-IL4) was compared in a macrophage/MSC co-culture system. Sterile or LPS-contaminated ultra-high molecular weight polyethylene particles were used to induce the proinflammatory responses in the macrophages. Contaminated particles induced M1 marker expression (TNFalpha, IL1beta, and iNOS), while NFkappaB-IL4 MSCs modulated the macrophages from an M1 phenotype into a more favorable M2 phenotype (Arginase 1/Arg 1 and CD206 high). The IL4 secretion by NFkappaB-IL4 MSCs was significantly induced by the contaminated particles. The induction of Arg 1 and CD206 in macrophages via the preconditioned or naive MSCs was negligible when compared with NFkappaB-IL4 MSC. Our findings indicated that NFkappaB-IL4 MSCs have the "on-demand" immunomodulatory ability to mitigate wear particle-associated inflammation with minimal adverse effects. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2018.

  View details for PubMedID 30084534

• Transplanted interleukin-4--secreting mesenchymal stromal cells show extended survival and increased bone mineral density in the murine femur. Cytotherapy Lin, T., Pajarinen, J., Kohno, Y., Maruyama, M., Romero-Lopez, M., Huang, J., Nathan, K., Khan, T. N., Yao, Z., Goodman, S. B. 2018

  Abstract

  BACKGROUND: Mesenchymal stromal cell (MSC)-based therapy has great potential to modulate chronic inflammation and enhance tissue regeneration. Crosstalk between MSC-lineage cells and polarized macrophages is critical for bone formation and remodeling in inflammatory bone diseases. However, the translational application of this interaction is limited by the short-term viability of MSCs after cell transplantation.METHODS: Three types of genetically modified (GM) MSCs were created: (1) luciferase-expressing reporter MSCs; (2) MSCs that secrete interleukin (IL)-4 either constitutively; and (3) MSCs that secrete IL-4 as a response to nuclear factor kappa-light-chain-enhancer of activated B cell (NFkappaB) activation. Cells were injected into the murine distal femoral bone marrow cavity. MSC viability and bone formation were examined in vivo. Cytokine secretion was determined in a femoral explant organ culture model.RESULTS: The reporter MSCs survived up to 4 weeks post-implantation. No difference in the number of viable cells was found between high (2.5 * 106) and low (0.5 * 106) cell-injected groups. Injection of 2.5 * 106 reporter MSCs increased local bone mineral density at 4 weeks post-implantation. Injection of 0.5 * 106 constitutive IL-4 or NFkappaB-sensing IL-4-secreting MSCs increased bone mineral density at 2 weeks post-implantation. In the femoral explant organ culture model, LPS treatment induced IL-4 secretion in the NFkappaB-sensing IL-4-secreting MSC group and IL-10 secretion in all the femur samples. No significant differences in tumor necrosis factor (TNF)alpha and IL-1beta secretion were observed between the MSC-transplanted and control groups in the explant culture.DISCUSSION: Transplanted GM MSCs demonstrated prolonged cell viability when transplanted to a compatible niche within the bone marrow cavity. GM IL-4-secreting MSCs may have great potential to enhance bone regeneration in disorders associated with chronic inflammation.

  View details for PubMedID 30077567