TY - JOUR
T1 - Synthesis and characterization of [125I]TZ6544, a promising radioligand for investigating sphingosine-1-phosphate receptor 2
AU - Luo, Zonghua
AU - Liang, Qianwa
AU - Liu, Hui
AU - Sumit, Joshi
AU - Jiang, Hao
AU - Klein, Robyn S.
AU - Tu, Zhude
N1 - Funding Information:
This study was supported by the USA National Multiple Sclerosis Society [RG150705331], the USA National Institutes of Health including the National Institute of Neurological Disorders and Stroke, and the National Institute on Aging [NS075527 and NS103988]. The authors declare that they have no conflict of interest. All applicable institutional and/or national guidelines for the care and use of animals were followed. This article does not contain any studies with human participants performed by any of the authors.
Funding Information:
This study was supported by the USA National Multiple Sclerosis Society [ RG150705331 ], the USA National Institutes of Health including the National Institute of Neurological Disorders and Stroke , and the National Institute on Aging [ NS075527 and NS103988 ].
Publisher Copyright:
© 2020 Elsevier Inc.
PY - 2020/9/1
Y1 - 2020/9/1
N2 - Introduction: Sphingosine-1-phosphate receptor 2 (S1PR2) activation exerts a critical role in biological abnormalities and diseases. A suitable radiotracer will advance our understanding of S1PR2 pathophysiology of diseases. The objective of this study is to evaluate the potential of iodine-125 labeled [125I]TZ6544 to be used for screening new compounds binding toward S1PR2, and assessing the changes of S1PR2 expression in the kidney of streptozotocin-induced diabetic rats. Methods: [125I]TZ6544 was synthesized from borate precursor by copper (II)-catalyzed iodization reaction with [125I]NaI. [125I]TZ6544 was characterized using human recombinant S1PR2 cell membrane and biodistribution studies of [125]TZ6544 were performed on Wistar rats that were euthanized at 5 and 30 min post-injection. A rat model of diabetes was induced by IV injection of streptozotocin (55 mg/kg). In vitro autoradiography studies, immunostaining, and enzyme-linked immunosorbent assay (ELISA) analysis were performed in both diabetic and control rats. Results: Radiosynthesis of [125I]TZ6544 was achieved successfully with good radiochemical yields of ~47% and high radiochemical purity of >99%. [125I]TZ6544 is a potent ligand in vitro for S1PR2 with Kd value of 4.31 nM. [125I]TZ6544 and [32P]-labeled endogenous S1P provided comparable IC50 values in radioactive competitive binding assays against known S1PR2 ligands. Compared to control, the kidney of diabetic rats had increased uptake of [125I]TZ6544, which could be reduced by a S1PR2 antagonist, JTE-013. Immunostaining and ELISA analysis confirmed that the diabetic rat had increased S1PR2 expression in the kidney. Conclusions: [125I]TZ6544 was synthesized successfully in high yields, and in vitro evaluation suggested [125I]TZ6544 has high potential to be used for screening new S1PR2 compounds and investigating the pathophysiology of S1PR2 functions. The availability of [125I]TZ6544 may facilitate the development of therapeutics and imaging agents targeting S1PR2. Advances in knowledge: [125I]TZ6544 showed increased expression of S1PR2 in diabetic rat kidney and can be used to determine binding potency of S1PR2 compounds.
AB - Introduction: Sphingosine-1-phosphate receptor 2 (S1PR2) activation exerts a critical role in biological abnormalities and diseases. A suitable radiotracer will advance our understanding of S1PR2 pathophysiology of diseases. The objective of this study is to evaluate the potential of iodine-125 labeled [125I]TZ6544 to be used for screening new compounds binding toward S1PR2, and assessing the changes of S1PR2 expression in the kidney of streptozotocin-induced diabetic rats. Methods: [125I]TZ6544 was synthesized from borate precursor by copper (II)-catalyzed iodization reaction with [125I]NaI. [125I]TZ6544 was characterized using human recombinant S1PR2 cell membrane and biodistribution studies of [125]TZ6544 were performed on Wistar rats that were euthanized at 5 and 30 min post-injection. A rat model of diabetes was induced by IV injection of streptozotocin (55 mg/kg). In vitro autoradiography studies, immunostaining, and enzyme-linked immunosorbent assay (ELISA) analysis were performed in both diabetic and control rats. Results: Radiosynthesis of [125I]TZ6544 was achieved successfully with good radiochemical yields of ~47% and high radiochemical purity of >99%. [125I]TZ6544 is a potent ligand in vitro for S1PR2 with Kd value of 4.31 nM. [125I]TZ6544 and [32P]-labeled endogenous S1P provided comparable IC50 values in radioactive competitive binding assays against known S1PR2 ligands. Compared to control, the kidney of diabetic rats had increased uptake of [125I]TZ6544, which could be reduced by a S1PR2 antagonist, JTE-013. Immunostaining and ELISA analysis confirmed that the diabetic rat had increased S1PR2 expression in the kidney. Conclusions: [125I]TZ6544 was synthesized successfully in high yields, and in vitro evaluation suggested [125I]TZ6544 has high potential to be used for screening new S1PR2 compounds and investigating the pathophysiology of S1PR2 functions. The availability of [125I]TZ6544 may facilitate the development of therapeutics and imaging agents targeting S1PR2. Advances in knowledge: [125I]TZ6544 showed increased expression of S1PR2 in diabetic rat kidney and can be used to determine binding potency of S1PR2 compounds.
KW - Autoradiography
KW - Biodistribution
KW - Diabetic nephropathy
KW - I-125 radioligand
KW - Sphingosine-1-phosphate receptor 2
UR - http://www.scopus.com/inward/record.url?scp=85089180406&partnerID=8YFLogxK
U2 - 10.1016/j.nucmedbio.2020.07.007
DO - 10.1016/j.nucmedbio.2020.07.007
M3 - Article
C2 - 32791475
AN - SCOPUS:85089180406
SN - 0969-8051
VL - 88-89
SP - 52
EP - 61
JO - Nuclear Medicine and Biology
JF - Nuclear Medicine and Biology
ER -