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:

[Retinoid therapy for autoimmune diseases].
Retinoid is a collective term for compounds which bind to and activate retinoic acid receptors (RARalpha, beta, gamma and RXRalpha, beta, gamma), members of nuclear hormone receptor superfamily. The most important endogeneous retinoid is all-trans-retinoic acid (ATRA) which is an RARalpha, beta and gamma ligand. ATRA and its mimics have been in clinical use for treatment of acute promyelocytic leukemia (APL) and some skin diseases. Many synthetic retinoids have been developed and attempts to improve their medicinal properties have been made. Among them, tamibarotene (Am80) is an RARalpha- and RARbeta-specific (but RARgamma- and RXRs-nonbinding) synthetic retinoid that is effective in the treatment of psoriasis patients and relapsed APL. Experimentally, this compound is also active in animal models of rheumatoid arthritis and experimental autoimmune encephalomyelitis. On this background, possible application of retinoids for the treatment of autoimmune diseases was discussed. In particular, Th1 dominant autoimmune diseases may be the targets of the retinoids.
{"Chemical": ["Retinoid", "tamibarotene", "retinoid", "ATRA", "Am80", "retinoids", "all-trans-retinoic acid"], "Protein": ["RXRs", "RARgamma", "RARbeta", "RARalpha", "RXRalpha, beta, gamma", "nuclear hormone receptor", "RARalpha, beta, gamma", "retinoic acid receptors", "RARalpha, beta and gamma"]}