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: ["Protein", "Chemical"].

Please return the output as a JSON object of the format: {"Chemical" : ["Dexamethasone", ...], "Protein" : ["BRCA-1", ...]}. 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:

Total saponins of Panax notoginseng enhance VEGF and relative receptors signals and promote angiogenesis derived from rat bone marrow mesenchymal stem cells.
ETHNOPHARMACOLOGICAL RELEVANCE: Total saponins of Panax notoginseng (tPNS), main constituents extracted from Panax Notoginseng, a highly valued traditional Chinese medicine, has been shown to increase protein expression and the secretion of vascular endothelial growth factor (VEGF) in human umbilical vein endothelial cells. AIMS OF THE STUDY: The effects of tPNS on angiogenesis were studied in rat bone marrow mesenchymal stem cells (rBMSCs). MATERIALS AND METHODS: rBMSCs were stimulated by tPNS of 48h. The mRNA expression levels of VEGF-A, Flt-1 and Kdr in rBMSCs were determined by quantitative real time PCR (qRT-PCR). rBMSCs were induced to differentiate into endothelial-like cells and the effects of tPNS on the angiogenesis ability of rBMSCs and rBMSCs after endothelial differentiation were assayed by a Matrigel model in vivo and in vitro. RESULTS: tPNS (100μg/ml) significantly enhanced the mRNA expression level of VEGF-A and Kdr compared to the control group, while they had no obvious effect on the expression of Flt-1. tPNS (1μg/ml and 100μg/ml) significantly increased capillary network forming of rBMSCs after endothelial differentiation in Matrigel in vitro. tPNS (50μg/kg, 100μg/kg and 150μg/kg) also significantly increased angiogenesis induced by the combination with implantation of rBMSCs and Matrigel in vivo. CONCLUSION: tPNS up-regulate VEGF-A and Kdr expression, and promote angiogenesis in rat bone marrow mesenchymal stem cells.
{"Chemical": ["saponins"], "Protein": ["VEGF-A", "Kdr", "vascular endothelial growth factor", "VEGF", "Flt-1"]}