2,4-dichlorophenoxyacetic acid induces ROS activation in NLRP3 inflammatory body-induced autophagy disorder in microglia and the protective effect of Lycium barbarum polysaccharide

The pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) exerts neurotoxic effects; however, its action mechanism remains unclear. Here, we used BV2 cells as a model and divided them into six groups: control group (serum-free medium), lipopolysaccharide (LPS) (1 μg/mL), 2,4-D (1.2 μmol/mL), Lycium barbarum polysaccharide (LBP; 300 μg/mL LBP), LPS (1 μg/mL) + LBP (300 μg/mL), and 2,4-D (1.2 μmol/mL) + LBP (300 μg/mL) with dimethyl sulfoxide as the solvent. Our results showed that 2,4-D treatment decreased superoxide dismutase and glutathione peroxidase activities and increased malondialdehyde content. The percentage of microglial activation (co-expression of ionized calcium-binding adaptor protein-1 + CD68) in the LPS and 2,4-D groups and the levels of tumor necrosis factor alpha, interleukin (IL) 1 beta, IL-6, and IL-18 in the cell supernatant were increased. The protein and mRNA levels of Nod-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein, caspase-1, IL-1β, IL-18, and p62 increased, whereas those of LC3II/I and Beclin-1 decreased in the 2,4-D group. The protein expression and mRNA levels of NLRP3, cleaved caspase-1, IL-1β, IL-18, and p62 decreased significantly, whereas the protein expression and mRNA levels of LC3II/I and Beclin-1 increased in small interfering RNA of NLRP3-treated BV2 cells stimulated with 2,4-D and LPS. In conclusion, 2,4-D enhanced cell migration, promoted oxidative stress, induced excessive release of mitochondrial reactive oxygen species, promoted microglial cell activation, released inflammatory factors, activated NLRP3 inflammasomes, and inhibited autophagy. Meanwhile, LBP reduced inflammation and the release of mitochondrial reactive oxygen species, inhibited NLRP3 inflammasome activation, and regulated autophagy, thereby playing a neuroprotective role.

Effects of 2,4-dichlorophenoxyacetic acid on the expression of NLRP3 inflammasome and autophagy-related proteins as well as the protective effect of Lycium barbarum polysaccharide in neonatal rats

The pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) has neurotoxic effects, but its mechanism is not clear. In this study, a 2,4-D (75 mg/kg. b.w) exposure model was established in SD rats with colostrum. Lipopolysaccharide (1 mg/kg b.w) was used as the positive control, and Lycium barbarum polysaccharide (LBP, 50 mg/kg b.w) was used as an intervention factor to explore the neurotoxic effect of 2,4-D and the neuroprotective effect of LBP. Our research results show that 2,4-D causes a decrease in the number of hippocampal CA3 pyramidal cells and pyknosis in nuclei with a triangular or irregular shape and that rats show signs of anxiety or depression. In rat serum, superoxide dismutase, and glutathione peroxidase activity decreased, while malondialdehyde content increased. Protein and mRNA levels of TNFα, IL-6, IL-1β, IL-18, NLRP3, ASC, caspase-1, IL-1β, IL-18, and p62 increased, while those of LC3-II/LC3-I and Beclin-1 decreased in hippocampal tissues. In conclusion, 2,4-D increased the oxidative stress level, induced neuroinflammatory response, and decreased the autophagy level in experimental rats. LBP may have upregulated the autophagy level in the body by inhibiting the activation of the NLRP3 inflammasome, thus playing a neuroprotective role.

Isometric Finger Pose Recognition with Sparse Channel SpatioTemporal EMG Imaging

High fidelity myoelectric control of prostheses and orthoses isparamount to restoring lost function to amputees and neuro-muscular disease sufferers. In this study we prove that patio-temporal imaging can be used to allow convolutional neural networks to classify sparse channel EMG samples from a consumer-grade device with over 94 % accuracy. 10,572 images are generated from 960 samples of simple and complex isometric finger poses recorded from 4 fully intact subjects. Real-time classification of 12 poses is achieved with a 250ms continuous overlapping window.

Wnt activation protects against neomycin-induced hair cell damage in the mouse cochlea

Recent studies have reported the role of Wnt/β-catenin signaling in hair cell (HC) development, regeneration, and differentiation in the mouse cochlea; however, the role of Wnt/β-catenin signaling in HC protection remains unknown. In this study, we took advantage of transgenic mice to specifically knockout or overactivate the canonical Wnt signaling mediator β-catenin in HCs, which allowed us to investigate the role of Wnt/β-catenin signaling in protecting HCs against neomycin-induced damage. We first showed that loss of β-catenin in HCs made them more vulnerable to neomycin-induced injury, while constitutive activation of β-catenin in HCs reduced HC loss both in vivo and in vitro. We then showed that loss of β-catenin in HCs increased caspase-mediated apoptosis induced by neomycin injury, while β-catenin overexpression inhibited caspase-mediated apoptosis. Finally, we demonstrated that loss of β-catenin in HCs led to increased expression of forkhead box O3 transcription factor (Foxo3) and Bim along with decreased expression of antioxidant enzymes; thus, there were increased levels of reactive oxygen species (ROS) after neomycin treatment that might be responsible for the increased aminoglycoside sensitivity of HCs. In contrast, β-catenin overexpression reduced Foxo3 and Bim expression and ROS levels, suggesting that β-catenin is protective against neomycin-induced HC loss. Our findings demonstrate that Wnt/β-catenin signaling has an important role in protecting HCs against neomycin-induced HC loss and thus might be a new therapeutic target for the prevention of HC death.

Reduced mtDNA copy number increases the sensitivity of tumor cells to chemotherapeutic drugs

Many cancer drugs are toxic to cells by activating apoptotic pathways. Previous studies have shown that mitochondria have key roles in apoptosis in mammalian cells, but the role of mitochondrial DNA (mtDNA) copy number variation in the pathogenesis of tumor cell apoptosis remains largely unknown. We used the HEp-2, HNE2, and A549 tumor cell lines to explore the relationship between mtDNA copy number variation and cell apoptosis. We first induced apoptosis in three tumor cell lines and one normal adult human skin fibroblast cell line (HSF) with cisplatin (DDP) or doxorubicin (DOX) treatment and found that the mtDNA copy number significantly increased in apoptotic tumor cells, but not in HSF cells. We then downregulated the mtDNA copy number by transfection with shRNA-TFAM plasmids or treatment with ethidium bromide and found that the sensitivity of tumor cells to DDP or DOX was significantly increased. Furthermore, we observed that levels of reactive oxygen species (ROS) increased significantly in tumor cells with lower mtDNA copy numbers, and this might be related to a low level of antioxidant gene expression. Finally, we rescued the increase of ROS in tumor cells with lipoic acid or N-acetyl-L-cysteine and found that the apoptosis rate decreased. Our studies suggest that the increase of mtDNA copy number is a self-protective mechanism of tumor cells to prevent apoptosis and that reduced mtDNA copy number increases ROS levels in tumor cells, increases the tumor cells' sensitivity to chemotherapeutic drugs, and increases the rate of apoptosis. This research provides evidence that mtDNA copy number variation might be a promising new therapeutic target for the clinical treatment of tumors.

Bmi1 regulates auditory hair cell survival by maintaining redox balance

Reactive oxygen species (ROS) accumulation are involved in noise- and ototoxic drug-induced hair cell loss, which is the major cause of hearing loss. Bmi1 is a member of the Polycomb protein family and has been reported to regulate mitochondrial function and ROS level in thymocytes and neurons. In this study, we reported the expression of Bmi1 in mouse cochlea and investigated the role of Bmi1 in hair cell survival. Bmi1 expressed in hair cells and supporting cells in mouse cochlea. Bmi1^−/− mice displayed severe hearing loss and patched outer hair cell loss from postnatal day 22. Ototoxic drug-induced hair cells loss dramatically increased in Bmi1^−/− mice compared with that in wild-type controls both in vivo and in vitro, indicating Bmi1^−/− hair cells were significantly more sensitive to ototoxic drug-induced damage. Cleaved caspase-3 and TUNEL staining demonstrated that apoptosis was involved in the increased hair cell loss of Bmi1^−/− mice. Aminophenyl fluorescein and MitoSOX Red staining showed the level of free radicals and mitochondrial ROS increased in Bmi1^−/− hair cells due to the aggravated disequilibrium of antioxidant–prooxidant balance. Furthermore, the antioxidant N-acetylcysteine rescued Bmi1^−/− hair cells from neomycin injury both in vitro and in vivo, suggesting that ROS accumulation was mainly responsible for the increased aminoglycosides sensitivity in Bmi1^−/− hair cells. Our findings demonstrate that Bmi1 has an important role in hair cell survival by controlling redox balance and ROS level, thus suggesting that Bmi1 may work as a new therapeutic target for the prevention of hair cell death.

[The effects of levothyroxine replacement therapy on bone and mineral metabolism in patients with hypothyroidism]

OBJECTIVE

To investigate the effects of short-term thyroid hormone replacement therapy on bone and mineral metabolism in patients with hypothyroidism.

METHODS

Enzyme linked immunosorbent assay (ELISA) was used to measure urinary deoxypyridinoline (DPD) and radioimmunoassay (RIA) to measure serum calcitonin (CT), parathyroid hormone (PTH-M), bone GLA protein (BGP), free T(3) (FT(3)), free T(4) (FT(4)) and thyroid-stimulating hormone (TSH) in 29 patients with hypothyroidism before and after treatment with levothyroxine for (11.5 +/- 2.5) months. Dual energy X-ray absorptiometry was used to measure bone mineral density (BMD) of their spine (L(2 - 4)) and femur neck, trochanter and Ward's triangle. The results were compared with those in 37 healthy controls.

RESULTS

In hypothyroidism patients before treatment, serum BGP level was significantly lower (P < 0.05) than but urinary DPD was similar with those of control. BMD was significantly lower in postmenopausal patients (P < 0.01 - 0.001) than that in control group, but there was no change in premenopausal patients. After replacement therapy serum BGP and urinary DPD elevated significantly (P < 0.05), whereas BMD decreased slightly both in the premenopausal and postmenopausal patients when compared with that before treatment, with no statistical significance (P > 0.05). BMD decreased by 0.7% and 1.7% - 5.1% in premenopausal and postmenopausal patients respectively, but there was no significant difference between these two groups (P > 0.05). FT(3) was positively correlated with BGP. FT(4) and FT(3) were positively correlated with DPD. BMD of femur neck and trochanter sites was negatively correlated with FT(4).

CONCLUSION

Short-term physiological dose levothyroxine replacement therapy causes increase of bone turnover and leads to bone mass loss to various extent on hypothyroidism patients.

[Changes of bone and mineral metabolism in patients with hyperthyroidism before and after treatment]

OBJECTIVE

To investigate the changes of bone and mineral metabolism in patients with hyperthyroidism before and after treatment.

METHODS

Enzyme linked immunosorbent assay was used to measure bone-specific alkaline phosphatase (BAP) and deoxypyridinoline (DPD); radioimmunoassay to to measure serum calcitonin (CT), parathyroid hormone (PTH-M), bone GLA protein (BGP) and other markers related to bone metabolism; dual energy X-ray absorptiometry to measure bone mineral density (BMD) of spine(L2-4) and femur(Neck, Troch, Ward's) in 45 patients with hyperthyroidism before and after treatment and 58 healthy volunteers.

RESULTS

The urinary DPD level was elevated by 527% in patients with hyperthyroidism before treatment. Compared to controls the serum ALP, BAP, BGP elevated by 62%, 146%, 87% (P < 0.001), BMD decreased to various extent, and women L2-4, Ward's were marked (P < 0.05). The results after treatment and before treatment showed that urinary DPD decreased by 79%; serum ALP, BAP, BGP decreased by 19.5%, 24.7%, 27.5% respectively (P < 0.001, 0.05, 0.05, > 0.05). All sites BMD increased, and women Troch sites were marked (P < 0.05). The correlation analysis showed that the urinary DPD was positively correlated with serum BGP(r = 0.349 P < 0.05). FT4 was positively correlated with BAP, ALP and DPD respectively) (r = 0.353, P < 0.05, r = 0.294 P = 0.05, r = 0.426 P < 0.01).

CONCLUSION

Hyperthyroidism bone disease is caused by excessive serum thyroid hormone that speeds up bone turnover and marked bone absorption compared to bone formation.