You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["RNA", "CellLine", "Protein", "DNA", "CellType"].

Please return the output as a JSON object of the format: {"DNA" : ["TAL1", ...], "RNA": ["mRNAs", ...], "CellLine": ["T cells", ...], "CellType": ["monocytes", ...], "Protein": ["IL-2", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

The human myelomonocytic cell line U-937 as a model for studying alterations in steroid-induced monokine gene expression: marked enhancement of lipopolysaccharide-stimulated interleukin-1 beta messenger RNA levels by 1, 25-dihydroxyvitamin D3. The active metabolite of vitamin D, 1, 25-dihydroxyvitamin D3 [ 1, 25- (OH) 2D3 ], is a potent regulator of human monocyte / macrophage function in vitro. To establish a model for 1, 25- (OH) 2D3 regulation of human monocyte monokine synthesis, three human cell lines (U-937, THP-1, and HL-60) were examined for: 1) the presence of functional 1, 25- (OH) 2D3 receptors; 2) the accumulation of interleukin-1 beta (IL-1 beta) mRNA and IL-1 beta protein in response to lipopolysaccharide (LPS); and 3) the regulation of this response by 1, 25- (OH) 2D3. All three cell lines expressed vitamin D receptor and had increased levels of IL-1 beta mRNA in response to LPS. Preincubation of cells with 1, 25- (OH) 2D3 augmented IL-1 beta mRNA levels only in U-937 and HL-60 cells. From these data, and taking into consideration their state of differentiation and relative ease of culture, U-937 was chosen over HL-60 and THP-1 as the cell line we further characterized. In U-937 cells, optimum time and dose of pretreatment with 1, 25- (OH) 2D3 were determined to be 12-24 h at a receptor saturating concentration of 1, 25- (OH) 2D3 (10 nM). Preincubation of cells with 1, 25- (OH) 2D3 had no effect on the time course of IL-1 beta mRNA appearance in response to LPS. However, exposure of U-937 cells to 1, 25- (OH) 2D3 increased by 200% the level of IL-1 beta mRNA detected and decreased by three orders of magnitude the concentration of LPS required to achieve steady state mRNA levels equivalent to those observed in U-937 cells not preincubated with the hormone. 2 + o
{"CellLine": ["THP - 1", "HL - 60 cells", "HL - 60", "U - 937", "human myelomonocytic cell line U - 937", "U - 937 cells", "human cell lines"], "CellType": [], "DNA": [], "Protein": ["IL - 1 beta", "interleukin - 1 beta", "IL - 1 beta protein"], "RNA": ["interleukin - 1 beta (IL - 1 beta) mRNA", "lipopolysaccharide - stimulated interleukin - 1 beta messenger RNA", "IL - 1 beta mRNA"]}