ABSTRACT
Accumulation of amyloid-ß (Aß) in brain tissue contributes to the pathophysiology of Alzheimer's disease (AD). We recently reported that intrahippocampal transplantation of mouse bone marrow-derived microglia-like (BMDML) cells suppresses brain amyloid pathology and cognitive impairment in a mouse model of AD. How these transplanted cells interact with resident microglia remains unknown. In the present study, we evaluated the effects of cytokines secreted from mouse BMDML cells on cultured mouse microglia. Conditioned medium from BMDML cells increased microglial Aß phagocytosis. High levels of transforming growth factor-ß1 (TGF-ß1) were present in the conditioned medium, and BMDML cells and microglia expressed Tgf-ß1 mRNA and TGF-ß receptor type 1 (TGF-ßR1) protein, respectively. BMDML conditioned medium also induced microglial Smad2/3 phosphorylation. A TGF-ßR1 inhibitor suppressed Smad2/3 phosphorylation and promotion of microglial Aß phagocytosis induced by conditioned medium. Recombinant mouse TGF-ß1 similarly increased microglial Aß phagocytosis and induced Smad2/3 phosphorylation, which were suppressed by the TGF-ßR1 inhibitor. Brain TGF-ß1 levels and resident microglial TGF-ß1R expression were increased by intrahippocampal injection of BMDML cells in a mouse model of AD. Cotreatment with the TGF-ßR1 inhibitor suppressed the ability of transplanted BMDML cells to increase microglial TGF-ß1R expression and decrease hippocampal Aß levels. Taken together, these findings suggested that transplanted BMDML cells secreted TGF-ß1 to stimulate Aß phagocytosis by resident microglia and decrease brain Aß pathology.
Subject(s)
Alzheimer Disease , Microglia , Amyloid beta-Peptides/metabolism , Animals , Bone Marrow/metabolism , Brain/metabolism , Mice , Mice, Transgenic , Microglia/metabolism , Phagocytosis , Transforming Growth Factor beta1/metabolismABSTRACT
Ca2+-permeable ion channels, such as transient receptor channels, are one of the potential therapeutic targets in cancer. Transient receptor potential vanilloid subtype 4 (TRPV4) is a nonselective cation channel associated with cancer progression. This study investigates the roles of TRPV4 in the pathogenesis of colitis-associated cancer (CAC) in mice. The role of TRPV4 was examined in azoxymethane (AOM)/dextran sulphate sodium (DSS)-induced murine CAC model. The formation of colon tumours induced by AOM/DSS treatment was significantly attenuated in TRPV4-deficient mice (TRPV4KO). TRPV4 was co-localised with markers of angiogenesis and macrophages. AOM/DSS treatment upregulated the expression of CD105, vascular endothelial growth factor receptor 2, and TRPV4 in wildtype, but the upregulation of CD105 was significantly attenuated in TRPV4KO. Bone marrow chimera experiments indicated that TRPV4, expressed in both vascular endothelial cells and bone marrow-derived macrophages, played a significant role in colitis-associated tumorigenesis. There was no significant difference in the population of hematopoietic cells, neutrophils, and monocytes between untreated and AOM/DSS-treated WT and TRPV4KO on flow cytometric analysis. TRPV4 activation by a selective agonist induced TNF-α and CXCL2 release in macrophages. Furthermore, TRPV4 activation enhanced the proliferation of human umbilical vein endothelial cells. These results suggest that TRPV4 expressed in neovascular endothelial cells and bone marrow-derived macrophages contributes to the progression of CAC in mice.
Subject(s)
Carcinogenesis/pathology , Colitis/pathology , Colonic Neoplasms/pathology , Neoplasms, Experimental/pathology , TRPV Cation Channels/metabolism , Animals , Azoxymethane/toxicity , Carcinogenesis/drug effects , Carcinogens/toxicity , Cell Proliferation/drug effects , Chemokine CXCL2/metabolism , Colitis/chemically induced , Colon/drug effects , Colon/pathology , Colonic Neoplasms/chemically induced , Dextran Sulfate/toxicity , Disease Progression , Human Umbilical Vein Endothelial Cells , Humans , Intestinal Mucosa/drug effects , Intestinal Mucosa/pathology , Macrophages/drug effects , Macrophages/metabolism , Macrophages/pathology , Male , Mice , Mice, Knockout , Neoplasms, Experimental/chemically induced , TRPV Cation Channels/agonists , TRPV Cation Channels/geneticsABSTRACT
Amyloid-ß (Aß) accumulation in the brain triggers the onset of Alzheimer's disease (AD), and its prevention and elimination are high priorities for anti-AD therapeutic strategies. Microglia, the resident immune cells in the brain, promote Aß clearance by phagocytosis. Previously, we demonstrated that injection of primary cultured rat microglia and mouse bone marrow-derived microglia-like cells into the brain decreases the level of Aß and that intrahippocampal injection of these cells ameliorates cognitive impairment in a mouse model of AD. To advance this cell therapeutic strategy to the clinical stage, less invasive ways of preparing autologous microglia-like cells from elderly patients are required. In this study, we demonstrated that hematopoietic stem cells mobilized from the bone marrow to peripheral blood by administering granulocyte colony-stimulating factor and a CXCR4 antagonist to mice differentiated into microglia-like cells upon stimulation with colony-stimulating factor 1 and interleukin-34. The peripheral blood-derived microglia-like (PBDML) cells expressed microglial markers and engaged in Aß phagocytosis. Although PBDML cells were in an anti-inflammatory state under nonstimulated conditions, they expressed mRNAs encoding proinflammatory cytokines following lipopolysaccharide treatment. PBDML cells injected into the hippocampi of a mouse AD model survived for at least 36 days while phagocytosing Aß, contributed to a reduction in brain Aß burden, and ameliorated cognitive impairment in the mice. These results strongly suggest that PBDML cells are a promising source for the development of a novel cell therapy against AD.
Subject(s)
Alzheimer Disease/therapy , Amyloid beta-Peptides/metabolism , Cognitive Dysfunction/therapy , Microglia/transplantation , Alzheimer Disease/psychology , Animals , Cognitive Dysfunction/psychology , Granulocyte Colony-Stimulating Factor/pharmacology , Hematopoietic Stem Cells , Humans , Macrophage Colony-Stimulating Factor/pharmacology , Maze Learning , Mice , Mice, Inbred C57BL , Phagocytosis , Primary Cell Culture , Rats , Receptors, CXCR4/antagonists & inhibitors , Recognition, Psychology , Survival AnalysisABSTRACT
BACKGROUND/AIM: Osteosarcoma is the most malignant type of bone tumor. Patients with osteosarcoma metastases have a poorer prognosis than those without metastases. Thus, the prognosis of osteosarcoma patients with metastases must be improved. MATERIALS AND METHODS: The present study investigated the inhibitory effects of 6-hydroxythiobinupharidine isolated from Nuphar pumilum on migration of LM8 murine osteosarcoma cells by a migration assay and also examined the expression of proteins related to actin dynamics by western blot. The present study also developed an automatic cell counting system using machine learning to count migrated cells by Fiji and Trainable Weka Segmentation. RESULTS: 6-Hydroxythiobinupharidine inhibited migration of LM8 osteosarcoma cells in a dose-dependent manner, and decreased protein expression of Lin11, Isl-1, and Mec-3 domain kinase 1 (LIMK1) and the levels of phosphorylated Cofilin. CONCLUSION: 6-Hydroxythiobinupharidine suppressed migration of LM8 osteosarcoma cells by decreasing expression of LIMK1. 6-Hydroxythiobinupharidine could be potentially used as an anti-metastatic compound.
