Project description:Introduction Iodine-131 (131I) is frequently used in nuclear medicine. Unbound or released 131I accumulate in the thyroid gland and may be detrimental to normal thyroid function. The aim of the present study was to identify biomarkers for 131I exposure in rat thyroid tissue and to assess the effect on thyroid function. Methods Thirty six male Sprague Dawley rats were i.v. injected with 150 Âµl saline solution containing 9.0, 88, 170, 260, 340, 760, 1300, or 4700 kBq (group A-H) 131I, or mock-treated with 150 Âµl saline solution only, and killed at 24 h after injection. Total RNA was extracted from individual thyroid tissue samples thyroids and mRNA levels were determined with the Agilent microarray platform. Results Estimated absorbed doses in treatment groups A-H was 0.0058, 0.057, 0.11, 0.17, 0.22, 0.5 Gy, 0.8 Gy, and 3 Gy. Totally, 429 transcripts were identified with a fold change fold change â¥ 1.5 and adjusted p-value â¤ 0.01. A trend with downregulation of thyroid hormone biosynthesis associated genes (e.g. thyroglobulin, thyroid peroxidase, the sodium-iodine symporter) was identified, but only statistically significant after 0.0058 and 0.22 Gy. Three transcripts coding for isoform 1 of the DBP protein showed a pattern with monotonous decrease in downregulation with absorbed dose between 0.0058-0.22 Gy. Changes in Dbp expression were not statistically significant between 0.5-3 Gy. However, a trend with downregulation at 0.5 and 0.8 Gy and upregulation and 3 Gy was identified. Previously, 131I (0.85-17 Gy) and 211At (0.023-32 Gy) exposure resulted in upregulation of Dbp in mice thyroid tissue 24 h after administrations. Additionally, a monotonous decrease in Dbp downregulation has been identified of in mouse kidney tissue at 8 and 12 months after 177Lu-octreotate administrations. Conclusion Conclusively, the Dbp gene is a promising candidate biomarker gene for exposure to 131I and possibly other internal radiation emitters. Further studies should be performed to establish how Dbp expression vary with dose-rate, absorbed dose, time after administration, different radiation qualities, and the function of Dbp. Total RNA was isolated from fresh-frozen individual thyroid tissue samples (Sprague Dawley rats). Each sample was run once. Four rats received the same treatment. Control samples (from non-irradiated rats) are included.

Project description:Background. Radioiodide 131I is commonly used to treat thyroid cancer and hyperthyroidism, and 131I releases during nuclear accidents have resulted in increased incidence of thyroid cancer in children. To develop a better understanding of underlying cellular mechanisms behind 131I exposure and identify potential biomarkers, the aim of this work was to study the long-term dose-related effects of 131I exposure in thyroid tissue and plasma in young rats. Materials and methods. Male Sprague Dawley rats (5-week-old) were i.v. injected with 0.5, 5.0, 50 or 500 kBq 131I (Dthyroid ca 1–1000 mGy), and killed after nine months at which time the thyroid and blood samples were collected. Gene expression microarray analysis (thyroid samples) and LC-MS/MS analysis (thyroid and plasma samples) were performed to assess differential gene and protein expression patterns in treated and corresponding untreated control samples. Bioinformatics analyses were performed using the DAVID functional annotation tool and Ingenuity Pathway Analysis (IPA). Results. Nine 131I exposure-related biomarkers (Afp and RT1-Bb,ARF3, DLD, IKBKB, NONO, RAB6A, RPN2, and SLC25A5) were identified in thyroid tissue. Four dose-related biomarker candidates (APRT, LDHA) and (TGM3 and DSG4) were identified in thyroid and plasma, respectively. Candidate biomarkers for thyroid function were the upstream regulator PPARG and the proteins ACADL and SORBS2 (all activities), TPO and TG (low activities)). 131I exposure was shown to have a profound effect on metabolism, the immune system, apoptosis and cell death. Furthermore, several signalling pathways essential for normal cellular function (actin cytoskeleton signalling, HGF signalling, NRF2-mediated oxidative stress, integrin signalling, calcium signalling) were also significantly regulated. Conclusion. Exposure-related and dose-related effects on gene and protein expression were observed, thereby identifying several candidate genes that could be used as potential biomarkers for exposure, absorbed dose and thyroid function.

Project description:Introduction Iodine-131 (131I) is frequently used in nuclear medicine. Unbound or released 131I accumulate in the thyroid gland and may be detrimental to normal thyroid function. The aim of the present study was to identify biomarkers for 131I exposure in rat thyroid tissue and to assess the effect on thyroid function. Methods Thirty six male Sprague Dawley rats were i.v. injected with 150 µl saline solution containing 9.0, 88, 170, 260, 340, 760, 1300, or 4700 kBq (group A-H) 131I, or mock-treated with 150 µl saline solution only, and killed at 24 h after injection. Total RNA was extracted from individual thyroid tissue samples thyroids and mRNA levels were determined with the Agilent microarray platform. Results Estimated absorbed doses in treatment groups A-H was 0.0058, 0.057, 0.11, 0.17, 0.22, 0.5 Gy, 0.8 Gy, and 3 Gy. Totally, 429 transcripts were identified with a fold change fold change ≥ 1.5 and adjusted p-value ≤ 0.01. A trend with downregulation of thyroid hormone biosynthesis associated genes (e.g. thyroglobulin, thyroid peroxidase, the sodium-iodine symporter) was identified, but only statistically significant after 0.0058 and 0.22 Gy. Three transcripts coding for isoform 1 of the DBP protein showed a pattern with monotonous decrease in downregulation with absorbed dose between 0.0058-0.22 Gy. Changes in Dbp expression were not statistically significant between 0.5-3 Gy. However, a trend with downregulation at 0.5 and 0.8 Gy and upregulation and 3 Gy was identified. Previously, 131I (0.85-17 Gy) and 211At (0.023-32 Gy) exposure resulted in upregulation of Dbp in mice thyroid tissue 24 h after administrations. Additionally, a monotonous decrease in Dbp downregulation has been identified of in mouse kidney tissue at 8 and 12 months after 177Lu-octreotate administrations. Conclusion Conclusively, the Dbp gene is a promising candidate biomarker gene for exposure to 131I and possibly other internal radiation emitters. Further studies should be performed to establish how Dbp expression vary with dose-rate, absorbed dose, time after administration, different radiation qualities, and the function of Dbp.

Project description:Transcriptomic profiling of normal mouse thyroid tissue following 211At irradiation Introduction The cellular response to stimuli can be studied on different molecular levels, including gene expression regulation. RNA microarray is a high-throughput technique that enables comparison of genome-wide transcriptional status between samples. 211At-labeled radiopharmaceuticals are potentially useful for tumor therapy. Metabolically released 211At accumulates in the thyroid gland, which is one of the main critical organs for such therapy. The aim of this study was to determine the effect of absorbed dose, dose-rate, and time after 211At exposure on transcriptional expression in mouse thyroid gland. Method BALB/c mice were i.v. injected with 1.7, 7.5 or 100 kBq 211At. Animals injected with 1.7 kBq were killed after 1, 6, or 168 h with mean absorbed doses to thyroid of 0.023, 0.32, and 1.4 Gy, respectively. Animals injected with 7.5 and 100 kBq were killed after 6 and 1 h, respectively, resulting in mean absorbed doses to thyroid of 1.4 Gy. Animals were killed through cardiac puncture under anesthesia, and thyroids were removed and snap-frozen. Total RNA was extracted from pooled thyroid tissue samples and mRNA levels were determined with the Illumina RNA microarray platform. Nexus Expression 3.0 was used to identify differentially expressed transcripts (adjusted p-value <0.01, fold change >1.5) and enriched GO terms (p-value <0.05) between irradiated groups and controls. Results In total, 1232 differentially expressed transcripts were detected after 211At administration, demonstrating a profound effect on gene regulation. The number of regulated transcripts increased with higher initial dose-rate/absorbed dose when the exposure time was 1 or 6 h. However, the number of regulated transcripts decreased with mean absorbed dose/time after 1.7 kBq 211At administration. This suggests that initial dose-rate (thus injected activity) is an important parameter in radiation-induced responses. Furthermore, the regulation profiles of groups administered 1.7 kBq were similar. Few previously proposed radiation responsive genes were identified in the present study, but, e.g. Gadd45g and Cdkn1a were among the regulated genes identified in the present study. A response involving immunological processes was identified especially at 1, 6, and 168 h after 1.7 kBq administration (0.023, 0.32, 1.8 Gy). Conclusion The present study allowed a comprehensive assessment of how variations in exposure parameters affect transcriptional regulation. The regulation profiles were dependent on both absorbed dose and time after exposure, but, initial dose-rate was the most influential parameter. Functional annotation of regulated genes revealed exposure-specific effects on biological processes. Additionally, we have identified several recurrently regulated genes after 211At exposure that may play a role in how mouse thyroid tissue responds to 211At exposure. Introduction The cellular response to stimuli can be studied on different molecular levels, including gene expression regulation. RNA microarray is a high-throughput technique that enables comparison of genome-wide transcriptional status between samples. 211At-labeled radiopharmaceuticals are potentially useful for tumor therapy. Metabolically released 211At accumulates in the thyroid gland, which is one of the main critical organs for such therapy. The aim of this study was to determine the effect of absorbed dose, dose-rate, and time after 211At exposure on transcriptional expression in mouse thyroid gland. Method BALB/c mice were i.v. injected with 1.7, 7.5 or 100 kBq 211At. Animals injected with 1.7 kBq were killed after 1, 6, or 168 h with mean absorbed doses to thyroid of 0.023, 0.32, and 1.4 Gy, respectively. Animals injected with 7.5 and 100 kBq were killed after 6 and 1 h, respectively, resulting in mean absorbed doses to thyroid of 1.4 Gy. Animals were killed through cardiac puncture under anesthesia, and thyroids were removed and snap-frozen. Total RNA was extracted from pooled thyroid tissue samples and mRNA levels were determined with the Illumina RNA microarray platform. Nexus Expression 3.0 was used to identify differentially expressed transcripts (adjusted p-value <0.01, fold change >1.5) and enriched GO terms (p-value <0.05) between irradiated groups and controls. Results In total, 1232 differentially expressed transcripts were detected after 211At administration, demonstrating a profound effect on gene regulation. The number of regulated transcripts increased with higher initial dose-rate/absorbed dose when the exposure time was 1 or 6 h. However, the number of regulated transcripts decreased with mean absorbed dose/time after 1.7 kBq 211At administration. This suggests that initial dose-rate (thus injected activity) is an important parameter in radiation-induced responses. Furthermore, the regulation profiles of groups administered 1.7 kBq were similar. Few previously proposed radiation responsive genes were identified in the present study, but, e.g. Gadd45g and Cdkn1a were among the regulated genes identified in the present study. A response involving immunological processes was identified especially at 1, 6, and 168 h after 1.7 kBq administration (0.023, 0.32, 1.8 Gy). Conclusion The present study allowed a comprehensive assessment of how variations in exposure parameters affect transcriptional regulation. The regulation profiles were dependent on both absorbed dose and time after exposure, but, initial dose-rate was the most influential parameter. Functional annotation of regulated genes revealed exposure-specific effects on biological processes. Additionally, we have identified several recurrently regulated genes after 211At exposure that may play a role in how mouse thyroid tissue responds to 211At exposure. Total RNA was isolated from fresh-frozen tissue samples (Normal balb/c mouse thyroids)

Project description:Transcriptomic profiling of normal mouse thyroid tissue following 211At irradiation Introduction The cellular response to stimuli can be studied on different molecular levels, including gene expression regulation. RNA microarray is a high-throughput technique that enables comparison of genome-wide transcriptional status between samples. 211At-labeled radiopharmaceuticals are potentially useful for tumor therapy. Metabolically released 211At accumulates in the thyroid gland, which is one of the main critical organs for such therapy. The aim of this study was to determine the effect of absorbed dose, dose-rate, and time after 211At exposure on transcriptional expression in mouse thyroid gland. Method BALB/c mice were i.v. injected with 1.7, 7.5 or 100 kBq 211At. Animals injected with 1.7 kBq were killed after 1, 6, or 168 h with mean absorbed doses to thyroid of 0.023, 0.32, and 1.4 Gy, respectively. Animals injected with 7.5 and 100 kBq were killed after 6 and 1 h, respectively, resulting in mean absorbed doses to thyroid of 1.4 Gy. Animals were killed through cardiac puncture under anesthesia, and thyroids were removed and snap-frozen. Total RNA was extracted from pooled thyroid tissue samples and mRNA levels were determined with the Illumina RNA microarray platform. Nexus Expression 3.0 was used to identify differentially expressed transcripts (adjusted p-value <0.01, fold change >1.5) and enriched GO terms (p-value <0.05) between irradiated groups and controls. Results In total, 1232 differentially expressed transcripts were detected after 211At administration, demonstrating a profound effect on gene regulation. The number of regulated transcripts increased with higher initial dose-rate/absorbed dose when the exposure time was 1 or 6 h. However, the number of regulated transcripts decreased with mean absorbed dose/time after 1.7 kBq 211At administration. This suggests that initial dose-rate (thus injected activity) is an important parameter in radiation-induced responses. Furthermore, the regulation profiles of groups administered 1.7 kBq were similar. Few previously proposed radiation responsive genes were identified in the present study, but, e.g. Gadd45g and Cdkn1a were among the regulated genes identified in the present study. A response involving immunological processes was identified especially at 1, 6, and 168 h after 1.7 kBq administration (0.023, 0.32, 1.8 Gy). Conclusion The present study allowed a comprehensive assessment of how variations in exposure parameters affect transcriptional regulation. The regulation profiles were dependent on both absorbed dose and time after exposure, but, initial dose-rate was the most influential parameter. Functional annotation of regulated genes revealed exposure-specific effects on biological processes. Additionally, we have identified several recurrently regulated genes after 211At exposure that may play a role in how mouse thyroid tissue responds to 211At exposure. Introduction The cellular response to stimuli can be studied on different molecular levels, including gene expression regulation. RNA microarray is a high-throughput technique that enables comparison of genome-wide transcriptional status between samples. 211At-labeled radiopharmaceuticals are potentially useful for tumor therapy. Metabolically released 211At accumulates in the thyroid gland, which is one of the main critical organs for such therapy. The aim of this study was to determine the effect of absorbed dose, dose-rate, and time after 211At exposure on transcriptional expression in mouse thyroid gland. Method BALB/c mice were i.v. injected with 1.7, 7.5 or 100 kBq 211At. Animals injected with 1.7 kBq were killed after 1, 6, or 168 h with mean absorbed doses to thyroid of 0.023, 0.32, and 1.4 Gy, respectively. Animals injected with 7.5 and 100 kBq were killed after 6 and 1 h, respectively, resulting in mean absorbed doses to thyroid of 1.4 Gy. Animals were killed through cardiac puncture under anesthesia, and thyroids were removed and snap-frozen. Total RNA was extracted from pooled thyroid tissue samples and mRNA levels were determined with the Illumina RNA microarray platform. Nexus Expression 3.0 was used to identify differentially expressed transcripts (adjusted p-value <0.01, fold change >1.5) and enriched GO terms (p-value <0.05) between irradiated groups and controls. Results In total, 1232 differentially expressed transcripts were detected after 211At administration, demonstrating a profound effect on gene regulation. The number of regulated transcripts increased with higher initial dose-rate/absorbed dose when the exposure time was 1 or 6 h. However, the number of regulated transcripts decreased with mean absorbed dose/time after 1.7 kBq 211At administration. This suggests that initial dose-rate (thus injected activity) is an important parameter in radiation-induced responses. Furthermore, the regulation profiles of groups administered 1.7 kBq were similar. Few previously proposed radiation responsive genes were identified in the present study, but, e.g. Gadd45g and Cdkn1a were among the regulated genes identified in the present study. A response involving immunological processes was identified especially at 1, 6, and 168 h after 1.7 kBq administration (0.023, 0.32, 1.8 Gy). Conclusion The present study allowed a comprehensive assessment of how variations in exposure parameters affect transcriptional regulation. The regulation profiles were dependent on both absorbed dose and time after exposure, but, initial dose-rate was the most influential parameter. Functional annotation of regulated genes revealed exposure-specific effects on biological processes. Additionally, we have identified several recurrently regulated genes after 211At exposure that may play a role in how mouse thyroid tissue responds to 211At exposure.

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