microRNA-124-3p inhibits the progression of congenital hypothyroidism via targeting programmed cell death protein 6

The Role of Thyroid Hormone Synthesis Gene-Related miRNAs Profiling in Structural and Functional Changes of The Thyroid Gland Induced by Excess Iodine

At recent years, the impairment caused by iodine excess are paid more attention. However, there is still largely unknown about the exact mechanism induced by excessive iodine. MiRNAs have been found to act as biomarkers for a variety of diseases, whereas fewer studies focused on miRNAs related to a cluster of genes regulating thyroid hormone synthesis, such as NIS, Pendrin, TPO, MCT8, TSHR, TSHα, and TSHβ-related miRNAs in structural and functional changes of the thyroid gland induced by subchronic and chronic high iodine exposure. In the present study, one hundred and twenty 4-week-old female Wistar rats were randomly divided into control group (I50µg/L KIO3); HI 1 (I6000µg/L KIO3); HI 2 (I10000µg/L KIO3); and HI 3 (I50000µg/L KIO3), the exposure period was 3 months and 6 months, respectively. The iodine contents in the urine and blood, thyroid function, and pathological changes were determined. In addition, levels of thyroid hormone synthesis genes and the associated miRNAs profiling were detected. The results showed that subclinical hypothyroidism occurred in the high iodine groups with subchronic high iodine exposure, while 6-month exposure led to hypothyroidism in the I10000µg/L and I50000µg/L groups. Subchronic and chronic high iodine exposure caused mRNA and protein levels of NIS, TPO, and TSHR decreased significantly, and Pendrin expression increased significantly. In addition, MCT8 mRNA and protein levels are only remarkably decreased under the subchronic exposure. PCR results showed that levels of miR-200b-3p, miR-185-5p, miR-24-3p, miR-200a-3p, and miR-25-3p increased significantly exposed to high iodine for 3 months, while miR-675-5p, miR-883-5p, and miR-300-3p levels increased significantly under the exposure to high iodine for 6 months. In addition, miR-1839-3p level was markedly decreased exposed to high iodine for 3 and 6 months. Taken together, the miRNA profiling of genes regulating thyroid hormone synthesis remarkably altered from subclinical hypothyroidism to hypothyroidism induced by excess iodine exposure, and some miRNAs may play an important role in subclinical hypothyroidism or hypothyroidism through regulating NIS, Pendrin, TPO, MCT8, and TSHR providing promising targets to alleviate the impairment on the structure and function of thyroid gland.

Interplay Between Non-Coding RNAs and Programmed Cell Death Proteins

Programmed cell death (PDCD) family of proteins includes at least 12 members, function of seven of them being more investigated. These members are PDCD1, PDCD2, PDCD4, PDCD5, PDCD6, PDCD7 and PDCD10. Consistent with the important roles of these proteins in the regulation of apoptosis, dysregulation of PDCDs is associated with diverse disorders ranging from intervertebral disc degeneration, amyotrophic lateral sclerosis, immune thrombocytopenia, type 1 diabetes, congenital hypothyroidism, Alzheimer’s disease to different types of cancers. More recently, the interaction between non-coding RNAs and different members of PDCD family is being discovered. In the current study, we described the functional interactions between PDCDs and two classes of non-coding RNAs, namely microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). miR-21 and miR-183 are two miRNAs whose interactions with PDCDs have been assessed in different contexts. The lncRNAs interaction with PDCDs is mainly assessed in the context of neoplasia indicating the role of MALAT1, MEG3, SNHG14 and LINC00473 in this process.

The effects of thyroid dysfunction on DNA damage and apoptosis in liver and heart tissues of rats

OBJECTIVES

Thyroid hormones affect many enzymes, organs, and systems. They also play a role in complex biological events including development and growth. The main objective of this study was to analyze the effects of thyroid dysfunction on DNA damage and apoptosis in liver and heart tissues as well as the treatment of these disorders.

METHODS

Thirty-eight Wistar-albino male rats were randomly divided into five groups: 1. Control group (n=6): The rats were sacrificed without any application and liver and heart samples were collected. 2. Hypothyroidism group (n=8): Prophyltiouracil (PTU)-10 mg/kg/day was applied to induce hypothyroidism by intraperitoneal route for two weeks. 3. Hypothyroidism + Thyroxine group (n=8): After one week of PTU application (10 mg/kg/day), a high dose of l-thyroxine (1.5 mg/kg/day) was applied by intraperitoneal route for one week. 4. Hyperthyroidism group (n=8): l-thyroxine (0.3 mg/kg/day) was applied intraperitoneally to induce hyperthyroidism for two weeks. 5. Hyperthyroidism + PTU group (n=8): After one week of high dose l-thyroxine application, PTU (10 mg/kg/day) was applied for one week.

RESULTS

Liver and heart tissues were collected to evaluate 8-hydroxy-2 deoxyguanosine (8-OHdG), caspase-8 and caspase-9 levels. Hypothyroidism caused DNA damage in the liver, while hyperthyroidism caused DNA damage in the heart tissue. Hyperthyroidism also led to a significant increase in levels of caspase-8 and caspase-9 in liver tissue.

CONCLUSIONS

The results of the study show that DNA damage and caspase levels in the heart and liver are affected differently in experimental hypothyroidism and hyperthyroidism.

The role of miRNA-624-5p in congenital hypothyroidism and its molecular mechanism by targeting SIRT1

BACKGROUND

Accumulating reports evidenced that congenital hypothyroidism (CH) is a kind of endocrine diseases caused by thyroid hormone imperfection. MicroRNAs (miRNAs) were confirmed to exhibit protective functions in CH progression. However, the functions and latent mechanism of microRNA-624-5p (miR-624-5p) in CH remains unknown.

OBJECTIVE

This report was designed to illustrate the potential molecular mechanisms of miR-624-5p on CH.

METHODS

Rats were induced by 50 mg/day propylthiouracil to conduct CH models. Free thyroxine (fT4) and thyroid-Stimulating hormone (TSH) concentrations were measured to confirm CH model conduction. The direct target of miR-624-5p was predicted and verified by Starbase and dual luciferase reporter assay. Besides, the levels of miR-624-5p and sirtuin1 (SIRT1) in hippocampus or hippocampal neuronal cells were assessed using quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot assays. Then CH rat behaviors were evaluated using open field test (OFT) and forced swim test (FST). Furthermore, neuronal cells viability and apoptosis were checked using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and flow cytometry.

RESULTS

qRT-PCR assay suggested that miR-624-5p was up-regulated and SIRT1 was low-expressed in hippocampus tissues of CH rats. SIRT1 was a direct target of miR-624-5p. MiR-624-5p inhibitor signally enhanced fT4 levels and reduced TSH levels in the plasma of CH rats, and improved CH rat depressive behaviors by targeting SIRT1. Moreover, our data also revealed that miR-624-5p inhibitor increased cell viability and reduced apoptotic neuronal cells, which was reversed by silencing of SIRT1.

CONCLUSIONS

Taken together, this research demonstrated that miR-624-5p serves as a promising target for CH treatment.

MicroRNA-489-3p plays a significant role in congenital hypothyroidism through regulating neuronal cell apoptosis via targeting translationally controlled tumor protein 1

Accumulating reports have indicated that congenital hypothyroidism (CH) is an endocrine disorder caused by underdeveloped thyroid gland or thyroid dyshormonogenesis. It has been also reported that certain microRNAs (miRNAs) may exert protective effects against the development of CH. However, whether miR-489-3p regulates CH progression remains unclear. The aim of the present study was to investigate the effects of miR-489-3p on CH and elucidate the underlying mechanisms. Therefore, Sprague Dawley rats were injected with propylthiouracil (50 mg/day) to establish a CH model. Reverse transcription-quantitative PCR (RT-qPCR) assay demonstrated that miR-489-3p was upregulated in the hippocampal tissues of CH rats. Furthermore, the TargetScan software was employed to predict the target gene of miR-489-3p, and a dual luciferase reporter assay revealed that translationally controlled tumor protein 1 (TPT1) was directly targeted by miR-489-3p. Additionally, RT-qPCR and western blot assays suggested that TPT1 was markedly downregulated in the hippocampal tissues of CH rats compared with control rats. In addition, inhibitor control, miR-489-3p inhibitor, control-shRNA or TPT1-shRNA were injected into CH rats. The results of the open-field and forced swimming tests revealed that miR-489-3p inhibitor notably improved the behavior of CH rats. Flow cytometry was applied to explore the effects of miR-489-3p inhibitor on neuronal cell apoptosis, and the findings indicated that miR-489-3p inhibitor attenuated CH-induced neuronal cell apoptosis, whereas these effects were reversed by treatment with miR-489-3p inhibitor and TPT1-shRNA. Finally, the function of miR-489-3p in neuronal cells was investigated in vitro. Neuronal cell viability, apoptosis and the expression of apoptosis-related proteins were determined using MTT assay, flow cytometry and western blot analysis, respectively. The results demonstrated that miR-489-3p inhibitor enhanced cell viability, suppressed apoptosis and upregulated Pim-3, phosphorylated (p)-Bad (Ser112) and Bcl-xL expression. Rescue experiments indicated that these effects were reversed following silencing of TPT1. Taken together, the findings of the present study demonstrated that miR-489-3p inhibitor could relieve CH-induced neurological damage through regulating TPT1 expression.

miR-124-3p Ameliorates Isoflurane-Induced Learning and Memory Impairment via Targeting STAT3 and Inhibiting Neuroinflammation

INTRODUCTION

Substantial evidence has indicated that isoflurane leads to learning and memory impairment. This study was designed to investigate the potential role of microRNA-124-3p (miR-124-3p) in isoflurane-induced learning and memory impairment in rats.

METHODS

Spatial learning and memory of rats were estimated by the Morris water maze (MWM) test after the construction of isoflurane-treated models. qRT-PCR was performed to assess the expression levels of miR-124-3p. The levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α in the hippocampal tissues were determined by enzyme-linked immunosorbent assay. The luciferase activity was determined by using a dual-luciferase reporter assay system.

RESULTS

The higher escape latency and lower time spent in the original quadrant were shown in isoflurane-treated rats compared with the control rats. Moreover, treatment with isoflurane could induce neuroinflammation, and miR-124-3p was poorly expressed in the hippocampal tissue of isoflurane-treated rats. Furthermore, STAT3 is a functional target of miR-124-3p, and inflammatory cytokine level was downregulated by miR-124-3p.

DISCUSSION/CONCLUSION

Combining the results of the current study demonstrates that miR-124-3p may have pivotal roles in improving isoflurane-induced learning and memory impairment via targeting STAT3 and inhibiting neuroinflammation.

MicroRNA-1236-3p/translationally controlled tumor protein (TPT1) axis participates in congenital hypothyroidism progression by regulating neuronal apoptosis

Congenital hypothyroidism (CH) is an endocrine disease caused by congenital thyroid hormone (TH) deficiency. MicroRNAs (miRNAs or miRs) have been reported to inhibit the progression of congenital hypothyroidism. However, the expression and role of miR-1236-3p in CH remains unclear. To address this, 12 day old Sprague-Dawley rats were divided into five groups: Control; Congenital hypothyroidism (CH), miR-1236-3p inhibitor control (inhibitor control); miR-1236-3p inhibitor (inhibitor); and miR-1236-3p inhibitor + translationally-controlled tumor protein 1 (TPT1)-small interfering (si)RNA (inhibitor + siRNA). Propylthiouracil (50 mg/day) was injected intraperitoneally into pregnant rats to generate pups with CH. The levels of miR-1236-3p and TPT1 were detected via reverse transcription-quantitative PCR and western blot analysis. Bioinformatics analysis was performed to predict the targets of miR-1236-3p, which was confirmed using dual luciferase reporter assay. Flow cytometry and MTT assay were used to measure neuronal cell apoptosis and cell viability, whereas western blotting was applied to detect the expression of Pim-3, p-Bad (Ser112), Bad and Bcl-xL, proteins associated with apoptosis. The results revealed that miR-1236-3p expression was significantly upregulated, whilst TPT1 expression was significantly downregulated in the hippocampus tissues of CH rats compared with the control group. TPT1 was confirmed as a target of miR-1236-3p. MiR-1236-3p inhibitor prevented hippocampal neuron apoptosis induced by CH induction, which was reversed by TPT1-siRNA transfection. In addition, following miR-1236-3p inhibitor transfection, neuronal cell apoptosis significantly reduced compared with the control group, which was accompanied by significantly increased expressions of Pim-3, p-Bad (Ser112) and Bcl-xL expression. These effects were reversed by TPT1-siRNA co-transfection. These results indicated that inhibition of miR-1236-3p expression inhibited neuron apoptosis in vivo and in vitro by targeting TPT1, serving a protective role in CH.