Response Of Bone Marrow-derived Cells Research Articles

Aberrant bone marrow-derived microglia in the hypothalamus may dysregulate appetite in diabetes

Bone marrow derived cells (BMDCs) migrate into the hypothalamus, where those cells give rise to microglia to regulate food intake. Given the fact that diabetes functionally impairs BMDCs, we hypothesized that diabetic microglia would fail to exhibit physiological function, accounting for hyperphagia in diabetes. To examine the role of BMDCs, total bone marrow cells from GFP transgenic mice were transplanted into wild type mice in which diabetes was induced by streptozotocin. We first confirmed that bone marrow transplantation could be utilized to examine BMDCs in the brain parenchyma as GFP positive cells could engraft the brain parenchyma and give rise to microglia even when the BBB was intact in the recipient mice. While diabetic mice manifested hyperphagia, BMDCs were in smaller number in the hypothalamus with less response to fasting in the brain parenchyma compared to nondiabetic mice. This finding was also confirmed by examining nondiabetic chimera mice in which BMDCs were diabetic. Those mice also exhibited less response of BMDCs in response to fasting. In conclusion, diabetic BMDCs had less response of microglia to fasting, perhaps accounting for diabetic hyperphagia.

Nuclear Transcription Factor Kappa B Downregulation Reduces Chemoresistance in Bone Marrow-derived Cells Through P-glycoprotein Modulation

Nuclear transcription factor kappa B (NF-κB) is associated with many types of refractory cancer. However, despite multiple strategies to treat cancer and novel target drugs, multidrug resistance still causes relapses. The best-characterized mechanism responsible for multidrug resistance involves the expression of the MDR-1 gene product, P-glycoprotein (P-gp). Because the direct inhibition of this protein is very toxic, other methods of multidrug resistance (MDR) regulation have been proposed. The MDR-1 promoter sequence contains a κB site, which is recognized by NF-κB. The aim of this work was to characterize whether NF-κB modulation changes the response of bone marrow-derived cells (BMDCs) to chemotherapy. We exposed BMDCs to etoposide and doxorubicin, two of the most used antineoplastic drugs. BMDCs presented high tolerance to these drugs, which correlated with high intrinsic P-gp activity and strong protein expression of NF-κB. To determine the mechanism behind the poor sensitivity of BMDCs to chemotherapy, we blocked the activity of the heterodimer protein NF-κB using the pharmacological inhibitor Bay 11-7085 and through the transfection of an adenovirus negative mutant of I kappa B alpha. The multidrug resistance phenotype of BMDCs was reversed by inhibiting the NF-κB pathway, and this change was accompanied by a decrease in P-gp activity. NF-κB is a possible target for improving the antineoplastic response.

Abstract 4983: The role of bone marrow derived tumor stromal cells in intestinal tumor response to Thymidylate Synthase Inhibitors inhibitors in the ApcMin/+ mouse.

Abstract Historically, most anti-cancer therapies have been developed to target cancer cells. For many decades, inhibitors of the enzyme thymidylate synthase (TS), such as fluoropyrimidines, have been used in the clinical management of various cancers. However, their clinical utility has been limited by their toxicity to normal cells and acquired resistance by tumor cells. More recently, the role of non-neoplastic cells in the tumor microenvironment on tumor initiation and progression has been firmly established. These non-neoplastic cells infiltrate the tumor and together with the extracellular matrix, blood vessels, connective tissue, and secreted molecules make up the tumor stroma. These cells are thought to play a role in tumor response to therapy. While therapeutic efficacy is often measured by its impact on tumor burden, the impact of TS inhibitors on tumor stromal cells is largely unknown. Bone marrow derived cells (BMDCs) are a major component of the tumor stroma.The goal of this project is to determine theirin mediating tumor response to systemic therapy with TS inhibitors. We hypothesize that in addition to targeting tumor cells, tumor stromal cells are also direct of TS inhibitors and thattumor response to therapy may in fact be dictated by stromal sensitivity to the therapy.To test this hypothesis, we generated chimeric wherein the chemo-sensitivity of intestinal tumor stromal cells to TS inhibitors was different from that of the tumor cells. We transplanted ApcMin/+ mice, a genetic model of intestinal tumorigenesis, with bone marrow cells that weregenetically modified to express a drug-resistant TS molecule from E. coli. We found that tumors in these mice were more resistant to a combined therapy of TS inhibitors as compared to mice transplanted with non-modified marrow. We identified examine the response of BMDCs in the tumor stroma that have previously been shown to promote intestinal tumor development, namely, myeloid derived suppressor cells (MDSCs), mast cells and T-regulatory (Treg) cells. We found that MDSCs, but not mast cells or Tregs were specifically sensitive to 5-fluorouracil (5-FU). Our data suggest that tumor response to 5-FU are at least in part mediated by MDSCs. Current studies are aimed at examining the response of other stromal components to 5-FU with the goal of developing strategies to enhance tumor sensitivity to TS inhibitors. Citation Format: Grishma Acharya, Celestia Davis, Nikeya Tisdale, Maria Marjorette O. Pena. The role of bone marrow derived tumor stromal cells in intestinal tumor response to Thymidylate Synthase Inhibitors inhibitors in the ApcMin/+ mouse. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4983. doi:10.1158/1538-7445.AM2013-4983

In vitro response of the bone marrow-derived mesenchymal stem cells seeded in a type-I collagen-glycosaminoglycan scaffold for skin wound repair under the mechanical loading condition.

In order to achieve successful wound repair by regenerative tissue engineering using mesenchymal stem cells (MSCs), it is important to understand the response of stem cells in the scaffold matrix to mechanical stress. To investigate the clinical effects of mechanical stress on the behavior of cells in scaffolds, bone marrow-derived mesenchymal stem cells (MSCs) were grown on a type-I collagen-glycosaminoglycan (GAG) scaffold matrix for one week under cyclic stretching loading conditions. The porous collagen-GAG scaffold matrix for skin wound repair was prepared, the harvested canine MSCs were seeded on the scaffold, and cultured under three kinds of cyclic stretching loading conditions (0%: control, 5% strain, 15% strain). After 7 days incubation, MSCs were evaluated histologically and immunohistochemically regarding the proliferation and differentiation. Cultured MSCs in the high strain (15% strain) group showed active alpha-smooth muscle actin (alpha-SMA) expression and poor differentiation into type-I collagen-positive cells, whereas enhanced differentiation into type-I collagen positive cells and a lack of alpha-SMA expression where shown in the lower stress (5% strain) group. These results suggest that mechanical stress may affect the proliferation and differentiation of stem cells, and subsequently the wound healing process, through attachment interactions between the stem cells and scaffold matrix. Our findings provide an additional consideration for clinical treatment of wound repair using regenerative tissue engineering.

Different response to osteo-inductive agents in bone marrow- and periosteum-derived cell preparations.

Rabbit bone marrow- and periosteum-derived cells were cultured in medium containing dexamethasone, bone morphogenetic protein-2 (BMP2) or both. The response of bone marrow-derived cells, measured as alkaline phosphatase expression, depended on the stage of growth. In subconfluent cultures, BMP2 had a greater effect than dexamethasone and treatment with both further increased enzyme activity. In confluent cultures, the effect of dexamethasone was greater than that of BMP2 and, when used together, they had an additive effect. The mineral deposition observed in these cultures did not have the typical structure of bone nodules. For periosteum-derived cells, dexamethasone did not increase the expression of alkaline phosphatase, while BMP2 did; treatment with both was less effective than treatment with BMP2 alone. Typical bone nodules were observed in cultures of periosteum-derived cells treated with dexamethasone and BMP2. These findings indicate that either osteoprogenitor cells from these two sources are intrinsically different or else non-progenitor cells in the preparations directly or indirectly affect the responsiveness to osteo-inductive agents.

Reconstitution of the Antibody Response in Vitro of T Cell-Deprived Spleen Cells by Supernatants from Spleen Cell Cultures

Abstract The antibody response of spleen cells against sheep red cells was tested in vitro with the Mishell-Dutton technique. Spleen cells deprived of thymus-derived (T) cells by anti-θ serum treatment gave a low response. Supernatants from cultures of either parental or syngeneic spleen cells could restore the response of T cell-deprived spleen cells against sheep red cells to a certain degree, but supernatants from mixed lymphocyte cultures between two H-2 incompatible parental strains were more efficient in this respect. These supernatants also could stimulate markedly the immune response of spleen cells from athymic “nude” mice. Addition of supernatants to cultures of normal or T cell-depleted cells caused an early appearance of plaque-forming cells by day 2 with a maximal number on day 3 for the T cell-depleted cells. Supernatants harvested on day 1 were more effective than supernatants from day 2 in restoring the immune response, whereas supernatants from days 3 and 4 were inhibitory. This was not due to an excessive production of the restorative factor. Both T cells and adherent cells were necessary for the production of the restorative factor. The active factor in the supernatants could be produced in serum-free medium and was capable of supporting a primary antibody response of spleen cells cultured in normal mouse serum. The findings suggest that T cells may stimulate the antibody response of bone marrow-derived cells by means of a soluble factor.