3-Methyladenine alleviates excessive iodine-induced cognitive impairment via suppression of autophagy in rat hippocampus

Urinary iodine concentrations in preschoolers and cognitive development at 4 and 6 years of age, the Rhea mother-child cohort on Crete, Greece

BACKGROUND

Evidence regarding child iodine intake and neurodevelopment is scarce.

METHODS

We aimed to assess the impact of child iodine intake at 4 years of age on cognitive and motor development at 4 and 6 years among 304 children from the Rhea cohort on Crete, Greece. Child iodine intake was assessed via urinary iodine concentrations (UIC) measured using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and adjusted for specific gravity. Child cognitive and motor development was assessed using the McCarthy Scales of Children's Abilities (MSCA) at 4 years of age and Raven's Coloured Progressive Matrices (RCPM), Finger Tapping Test (FTT), and Trail Making Test (TMT) at 6 years. Associations were explored using multivariable-adjusted linear regression analyses with UIC categorized according to WHO criteria [insufficient intake <100 µg/L, adequate 100-299 µg/L (reference group), excessive ≥300 µg/L].

RESULTS

The children's median UIC was 249 µg/L (25-75th percentile: 181-344 μg/L). Children with UIC <100 μg/L had lower scores in the motor scale at 4 years (MSCA-motor scale: B=-10.3; 95 %CI -19.9, -0.6; n=10) and in intelligence at 6 years (RCPM-total score: B=-3.6, 95 %CI -6.8, -0.5; n=9) than children in the reference group. No associations were found with the general cognitive scale at 4 years or with TMT and FTT scales at 6 years. Children with UIC ≥300 μg/L had lower cognitive scores both at 4 (MSCA; B= -3.5; 95 %CI -6.9, -0.1; n =101) and 6 years of age (RCPM-total score; B= -1.2; 95 %CI -2.3, -0.0; n =98) than children in the reference group. No associations were observed with the motor scale at 4 years or with TMT and FTT scales at 6 years.

CONCLUSION

Our findings indicate that both low and excessive iodine intake at preschool age may adversely affect child cognitive abilities. Additionally, low iodine intake may also impact motor abilities.

Recent advances of vacuolar protein-sorting 34 inhibitors targeting autophagy

Autophagy is a ubiquitous pathological/physiological antioxidant cellular reaction in eukaryotic cells. Vacuolar protein sorting 34 (Vps34 or PIK3C3), which plays a crucial role in autophagy, has received much attention. As the only Class III phosphatidylinositol-3 kinase in mammals, Vps34 participates in vesicular transport, nutrient signaling and autophagy. Dysfunctionality of Vps34 induces carcinogenesis, and abnormal autophagy mediated by dysfunction of Vps34 is closely related to the pathological progression of various human diseases, which makes Vps34 a novel target for tumor immunotherapy. In this review, we summarize the molecular mechanisms underlying macroautophagy, and further discuss the structure-activity relationship of Vps34 inhibitors that have been reported in the past decade as well as their potential roles in anticancer immunotherapy to better understand the antitumor mechanism underlying the effects of these inhibitors.

A study of programmed death-1/programmed death ligand and iodine-induced autoimmune thyroiditis in NOD.H-2h4 mice

Excess iodine will trigger the occurrence of autoimmune thyroiditis (AIT), and programmed death-1 (PD-1)/programmed death ligand (PD-L) will also contribute to the development of AIT. The purpose of this study was to explore the role that negative regulatory signals mediated by PD-1/PD-L play in the development of spontaneous autoimmune thyroiditis (SAT) in NOD.H-2h4 mice when they are exposed to iodine. Programmed death ligand 1 (PD-L1) antibody was administered intraperitoneally to NOD.H-2h4 mice. The relevant indicators were determined by flow cytometry, real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, immunohistochemistry, pathological hematoxylin and eosin staining, and arsenic-cerium catalytic spectrophotometry. Results showed that the level of urinary iodine, the level of thyroid lymphocyte infiltration, the level of thyroglobulin antibodies (TgAb) and interferon (IFN-γ)/tumor necrosis factor (TNF-α)/interleukin (IL-2)/IL-17, and the relative expression of PD-1/PD-L1/programmed death-2 (PD-L2) increased with the intervention of excess iodine. After the intervention of the PD-L1 antibody, the expression of PD-1/PD-L1/PD-L2 in different degrees was inhibited, but the level of thyroid lymphocyte infiltration and serum TgAb/IFN-γ/TNF-α/ IL-2/IL-17 did not decrease. Collectively, although PD-1/PD-L participates in the occurrence of SAT and induces inflammation, administration of the PD-L1 antibody does not effectively improve the pathological process of SAT. More research is needed to determine whether PD-1/PD-L intervention can treat autoimmune thyroid disease.

3-Methyladenine ameliorates surgery-induced anxiety-like behaviors in aged mice by inhibiting autophagy-induced excessive oxidative stress

BACKGROUND

Postoperative anxiety is a common surgical complication in older patients. Research has recently linked excessive autophagy to several neurological disorders, including anxiety. This study aimed to determine whether 3-Methyladenine (3-MA) administration reduced anxiety-like behaviors in a mouse model following abdominal exploratory laparotomy.

METHODS

An abdominal exploratory laparotomy model of postoperative anxiety was established using male C57BL/6 mice aged 20 months. 3-MA (6, 30, and 150 mg/ml) was administered via intracerebroventricular immediately following surgery. The mice were assessed 14 days after surgery using the marble burying, elevated plus maze tests, and local field potential recording in the amygdala. The levels of expression of phosphorylated-Akt, Beclin-1, LC3B, nuclear factor erythroid 2-related factor 2 (Nrf2)-occupied regions in NeuN-positive cells, superoxide dismutase (SOD) activity, malondialdehyde (MDA), and glutathione (GSH) were measured at 24 h after surgery.

RESULTS

The injection of 3-MA reversed the increased number of marbles buried, decreased time spent in the open arm, and enhanced θ oscillation power after 14 days of abdominal exploratory laparotomy. In addition, administration of 3-MA reduced the ratio of phosphorylated- to total-Akt, decreased expression in Beclin-1 and LC3B, attenuated MDA levels, and increased the ratio of Nrf2-occupied areas in NeuN-positive cells, SOD activity, and GSH levels under abdominal exploratory laparotomy conditions.

CONCLUSIONS

3-MA improved anxiety-like behaviors in aged mice undergoing abdominal exploratory laparotomy by inhibiting excessive autophagy-induced oxidative stress. These results suggest that 3-MA could be an effective treatment for postoperative anxiety.

Iodide intake during pregnancy and lactation stimulates KLF9, BDNF expression in offspring brain with elevated DHA, EPA metabolites

To investigate the effect of different iodide intake during pregnancy and lactation on thyroid function, docosahexaenoic acid (DHA), Eicosapentaenoic acid (EPA) metabolites, the expression of Krüppel-like factor KLF9 (KLF9), brain-derived neurotrophic factor (BDNF) in brain in offspring rats. In both male and female offspring rats, serum FT3, FT4 levels and the expression of KLF9, thyroid hormone receptors (TR)α, TRβ and BDNF in the hippocampal region and cerebellum were significantly increased in 5 times higher-than-normal pregnant iodide intake (5 HI) and 10 times higher-than-normal pregnant iodide intake (10 HI) group. The median levels of DHA metabolite (17-HDoHE) and EPA metabolites (15-HEPE, 17,18-EEQ, 9-HEPE and 14,15-DiHETE) were significantly increased in 5 HI and 10 HI group of offspring rats. Serum DHA, EPA metabolites and KLF9 as well as BDNF expression in brain might be potential iodine status biomarkers to reflect brain development in offspring.

The effect and mechanism of excessive iodine on the endothelial function of human umbilical vein endothelial cells

Iodine excess (IE) can cause thyroid dysfunction, thyroid diseases can adversely affect cardiovascular function. Accordingly, this study was to explore the direct and indirect effects of IE on endothelial function. Nthy-ori 3-1 and HUVECs cells were treated with potassium iodide (KI). CCK-8, LDH leakage, Elisa, RT-PCR and Western blotting were used to detect relevant indicators. Results showed that a certain level of KI can directly and indirectly reduce the viability of HUVECs and increase cytotoxicity. KI decreased the expression of ET-1 and VWF in HUVECs, inhibited the secretion of ET-1 in culture medium, and increased the expression of IL-6 and TNFα in HUVECs or Nthy-ori 3-1 cells alone. In the co-culture system, KI decreased the expression of ET-1 and THBD and increased the expression of TNFα and IL-6. Collectively, IE can directly and indirectly inhibit endothelial function of endothelial cells, which may be related to its induced inflammatory response.

Electroacupuncture improves cognitive impairment in diabetic cognitive dysfunction rats by regulating the mitochondrial autophagy pathway

Background

Diabetes-associated cognitive dysfunction has become a major public health concern. However, the mechanisms driving this disease are elusive. Herein, we explored how electroacupuncture improves learning and memory function in diabetic rats.

Methods

The diabetic model was established by intraperitoneal injection of streptozotocin (STZ) in adult Sprague–Dawley rats. Rats were fed on high-fat and high-sugar diets. Learning and memory functions were assessed using behavioral tests. The hematoxylin and eosin (H&E) staining, Western blotting, real-time PCR, ELISA, immunohistochemistry, and transmission electronic microscopy (TEM) was performed to test related indicators.

Results

High-fat and high-sugar diets impaired learning and memory function in rats, while electroacupuncture treatment reversed these changes. The model group presented highly prolonged escape latency compared to the control group, indicating impaired learning and memory functions. The TEM examination showed that electroacupuncture enhanced Aβ clearance and mitochondrial autophagy in hippocampal neuronal cells by increasing DISC1 expression.

Conclusions

Electroacupuncture improves learning and memory function in diabetic rats by increasing DISC1 expression to promote mitophagy. This enhanced Aβ clearance, alleviating cytotoxicity in hippocampal neuronal cells.

Long-term repetitive exposure to excess iodine induces mitochondrial apoptosis, and alters monoamine neurotransmitters in hippocampus of rats of different genders

The influence of excess iodine on human health has been paid more and more attention. Although numerous studies have reported that excess iodine may cause deleterious effects, the mental damage and its mechanism is yet to be identified. Using Sprague-Dawley rats exposed to excess iodine from pregnancy to 6 months post-delivery as in vivo model, this study explored the impacts of long-term repetitive excess iodine administration on the hippocampus of offspring rats, focusing on mitochondrial apoptosis pathway, with changes in monoamine neurotransmitters. The results showed that excess iodine could increase urinary iodine and brain organ coefficient in offspring of both genders, change the hippocampal cell structure, and damage the spatial learning and memory capacities. Poly ADP-ribose polymerase (PARP), P53, Cleaved Caspase-3, and cytochrome C proteins expression increased and Bcl2 protein expression decreased in hippocampus of excess iodine-treated offspring, indicating that excess iodine could activate the mitochondrial apoptosis pathway. Besides, excess iodine showed different effects on monoamine neurotransmitter in different gender. Collectively, our experimental data indicated that the learning and memory impairment induced by excess iodine may be mediated via mitochondrial apoptotic pathway. Long-term repetitive excess iodine exposure affected monoamine neurotransmitters in hippocampus of offspring rats.

The negative effect of the PI3K inhibitor 3-methyladenine on planarian regeneration via the autophagy signalling pathway

As an important PI3K (VPS34) inhibitor, 3-methyladenine (3-MA) can block the formation of autophagic vesicles in animals. Most toxicological studies using 3-MA have shown that 3-MA leads to serious disorders via autophagy suppression in mammals. However, no toxicological research on 3-MA has been performed on individuals undergoing regeneration. The freshwater planarian has powerful regenerative capability, and it can regenerate a new brain in 5 days and undergo complete adult individual remodelling in approximately 14 days. Moreover, it is also an excellent model organism for studies on environmental toxicology due to its high chemical sensitivity and extensive distribution. Here, Dugesia japonica planarians were treated with 3-MA, and the results showed that autophagy was inhibited and Djvps34 expression levels were down-regulated. After exposure to 10 mM 3-MA for 18 h, all the controls showed normal phenotypes, while one-half of the planarians treated with 3-MA showed morphological defects. In most cases, an ulcer appeared in the middle of the body, and a normal phenotype was restored 7 days following 3-MA exposure. During regeneration, disproportionate blastemas with tissue regression were observed. Furthermore, 3-MA treatment suppressed stem cell proliferation in intact and regenerating worms. These findings demonstrate that autophagy is indispensable for tissue homeostasis and regeneration in planarians and that 3-MA treatment is detrimental to planarian regeneration via its effect on the autophagy pathway.