Human ID2 ELISA Matched Antibody Pair

Among the diverse cytokines involved in osteoclast differentiation, interleukin (IL)-3 inhibits RANKL-induced osteoclastogenesis. However, the mechanism underlying IL-3-mediated inhibition of osteoclast differentiation is not fully understood. Here we demonstrate that the activation of signal transducers and activators of transcription 5 (STAT5) by IL-3 inhibits RANKL-induced osteoclastogenesis through the induction of the expression of Id genes. We found that STAT5 overexpression inhibited RANKL-induced osteoclastogenesis. However, RANKL did not regulate the expression or activation of STAT5 during osteoclast differentiation. STAT5 deficiency prevented IL-3-mediated inhibition of osteoclastogenesis, suggesting a key role of STAT5 in IL-3-mediated inhibition of osteoclast differentiation. In addition, IL-3-induced STAT5 activation upregulated the expression of Id1 and Id2, which are negative regulators of osteoclastogenesis. Overexpression of ID1 or ID2 in STAT5-deficient cells reversed osteoclast development recovered from IL-3-mediated inhibition. Importantly, microcomputed tomography and histomorphometric analysis revealed that STAT5 conditional knockout mice showed reduced bone mass, with an increased number of osteoclasts. Furthermore, IL-3 inhibited RANKL-induced osteoclast differentiation less effectively in the STAT5 conditional knockout mice than in the wild-type mice after RANKL injection. Taken together, our findings indicate that STAT5 contributes to the remarkable IL-3-mediated inhibition of RANKL-induced osteoclastogenesis by activating Id genes and their associated pathways.

ID genes have an important function in the cell cycle, and ID proteins may help identify aggressive tumors, besides being considered promising therapeutic targets. However, their role in thyroid tumors is still poorly understood. We examined ID expression and their correlation with diagnostic and prognostic features aiming to find a clinical application in differentiated thyroid carcinoma (DTC) cases. mRNA levels of ID1, ID2, ID3, and ID4 genes were quantified and their expression was observed by immunohistochemistry in 194 thyroid samples including 68 goiters, 16 follicular adenomas, 75 classic papillary thyroid carcinomas, 18 follicular variants of papillary thyroid carcinoma, 5 follicular thyroid carcinomas, and 1 anaplastic thyroid cancer, besides 11 normal thyroid tissues. DTC patients were managed according to standard protocols and followed up for M=28 +/- 16months. ID2, ID3, and ID4 mRNA levels were higher in benign (2.0 +/- 1.9; 0.6 +/- 0.6; and 0.7 +/- 1.0AU, respectively) than those in malignant nodules (0.30 +/- 0.62; 0.3 +/- 0.3; and 0.2 +/- 0.3AU, respectively, p<0.0001 for all three genes) and were associated with no extra thyroid invasion or metastasis at diagnosis. ID3 nuclear protein expression was higher in benign than that in malignant cells (5.2 +/- 0.9 vs 3.0 +/- 1.8AU; p<0.0001). On the contrary, the cytoplasmic expression of ID3 was higher in malignant than that in benign lesions (5.7 +/- 1.5 vs 4.0 +/- 1.4AU; p<0.0001). Our data indicate that ID genes are involved in thyroid tumorigenesis and suggest these genes act impeding the evolution of more aggressive phenotypes. The different patterns of their tissue expression may help identify malignancy and characterize thyroid lesion aggressiveness.