MicroRNA-294 Regulates Apoptosis of the Porcine Cerebellum Caused by Selenium Deficiency via Targeting iNOS

Left ventricle function and post-transcriptional events with exercise training in pigs

BACKGROUND

Standardized exercise protocols have been shown to improve overall cardiovascular fitness, but direct effects on left ventricular (LV) function, particularly diastolic function and relation to post-transcriptional molecular pathways (microRNAs (miRs)) are poorly understood. This project tested the central hypothesis that adaptive LV remodeling resulting from a large animal exercise training protocol, would be directly associated with specific miRs responsible for regulating pathways relevant to LV myocardial stiffness and geometry.

METHODS AND RESULTS

Pigs (n = 9; 25 Kg) underwent a 4 week exercise training protocol (10 degrees elevation, 2.5 mph, 10 min, 5 days/week) whereby LV chamber stiffness (KC) and regional myocardial stiffness (rKm) were measured by Doppler/speckle tracking echocardiography. Age and weight matched non-exercise pigs (n = 6) served as controls. LV KC fell by approximately 50% and rKm by 30% following exercise (both p < 0.05). Using an 84 miR array, 34 (40%) miRs changed with exercise, whereby 8 of the changed miRs (miR-19a, miR-22, miR-30e, miR-99a, miR-142, miR-144, miR-199a, and miR-497) were correlated to the change in KC (r ≥ 0.5 p < 0.05) and mapped to matrix and calcium handling processes. Additionally, miR-22 and miR-30e decreased with exercise and mapped to a localized inflammatory process, the inflammasome (NLRP-3, whereby a 2-fold decrease in NLRP-3 mRNA occurred with exercise (p < 0.05).

CONCLUSION

Chronic exercise reduced LV chamber and myocardial stiffness and was correlated to miRs that map to myocardial relaxation processes as well as local inflammatory pathways. These unique findings set the stage for utilization of myocardial miR profiling to identify underlying mechanisms by which exercise causes changes in LV myocardial structure and function.

Selenium Deficiency Induces Apoptosis, Mitochondrial Dynamic Imbalance, and Inflammatory Responses in Calf Liver

Selenium (Se) deficiency significantly impacts the cow breeding industry by reducing the milk quality of dairy cows and affecting the health of calves. The molecular mechanism of Se deficiency-induced damage to calves, however, remains unclear. The present study investigated whether Se deficiency induces oxidative stress, apoptosis, and inflammation in calf liver tissues. We collected the liver tissues of calves with Se deficiency. Experimental results showed that Se deficiency weakened the activity of antioxidant enzymes and increased the accumulation of oxidation products in the liver. Se deficiency also led to excessive fission of the mitochondria and downregulated the expression of the Mfn2 and Opa1 genes in the calf liver. Mitochondrial damage-induced apoptosis by increasing the expression of pro-apoptotic genes such as CytC, Cas3, Cas9, fas, and Cas8, leading to a decrease in energy metabolism. Se deficiency also triggered the expression of inflammatory-related factors such as IL-1β, IL-6, TNF-α, and NF-κB. Taken together, the results suggest that Se deficiency causes oxidative stress, triggers an inflammatory response, disrupts mitochondrial dynamic balance, and then induces apoptosis, eventually leading to calf liver damage. These findings might provide valuable clues for elucidating the mechanism of Se deficiency-induced injury in domestic animals.

1,8-cineole alleviates bisphenol A-induced apoptosis and necroptosis in bursa of Fabricius in chicken through regulating oxidative stress and PI3K/AKT pathway

Bisphenol A (BPA), an important chemical raw material, is now a ubiquitous environmental contaminant. As an endocrine disruptor similar to estrogen, BPA increases the risk of various metabolic and chronic diseases. BPA has immunotoxicity to humans and animals. 1,8-cineole (CIN) is a plant-derived monoterpene with antioxidant and antiapoptosis actions. However, there are no reports about whether CIN could antagonize the BPA-induced apoptosis and necroptosis in bursa of Fabricius (BF) of chicken. This study was to elucidate the ameliorative mechanism of CIN on the apoptosis and necroptosis in BF induced by BPA. 120 broilers (1-day-old) were randomly divided into four groups: control group, CIN group, CIN and BPA co-treatment group, and BPA group. TUNEL analysis results, histopathological variations, and the overexpression of proapoptosis biomakers (Caspase 3, Bax, Cyt-c, and p53) and necroptosis pathway-related factors (RIPK1, RIPK3, MLKL, and FADD) indicated that BPA exposure induced the apoptosis and necroptosis in chicken BF. Moreover, BPA treatment elevated the levels of oxidative stress indexes (MDA, iNOS, and NO) and weaken antioxidases activity (SOD, GPx, and CAT) and total antioxidant capacity in chicken BF. BPA administration also lessened the expression of PI3K and AKT and promoted HSPs (HSP27, HSP40, HSP60, and HSP70) activation. whereas CIN supplementation prominently mitigated BPA-caused these changes and the apoptosis and necroptosis damages. In brief, this study illuminated that CIN could protect the chicken BF against BPA-induced apoptosis and necroptosis through restraining oxidative stress and activating PI3K/AKT pathway.

Maternal selenium deficiency suppresses proliferation, induces autophagy dysfunction and apoptosis in the placenta of mice

Selenium deficiency is thought to be associated with the occurrence of gestational complications. However, the underlying mechanism of selenium deficiency impairs placental function remains unclear. In this study, female mice were separately supplemented with a Se-deficient (0.02 mg/kg Se) or control diet (0.2 mg/kg Se) for 12 weeks before mating and throughout gestation. Maternal liver and placentas were collected at embryonic day 15.5 and analyzed for Se content. Oxidative stress status, proliferation capability, autophagy, and apoptosis of the placenta were determined. We found that maternal selenium deficiency decreased placental Se concentration and some antioxidant selenoproteins expressions. The concentrations of catalase and glutathione in selenium-deficient placentas were reduced, along with an increase in hydrogen peroxide (H2O2) content. Selenium deficiency inhibited the expression of proliferating cell nuclear antigen. Autophagosomes, autophagolysosomes, and upregulation of autophagy-related protein microtubule-associated protein 1 light chain 3 alpha II (LC3B), Beclin1, PTEN-induced putative kinase 1 (PINK1), and Parkin were found in the selenium-deficient trophoblasts. Autophagic substrate p62/sequestosome 1 was surprisingly increased, indicating autophagy flux dysfunction. Selenium deficiency increased expressions of B cell leukemia/lymphoma 2 associated X protein (Bax), cleaved caspase-9/-3, and decreased the B cell leukemia/lymphoma 2 (Bcl2) level. Moreover, typical apoptotic ultrastructure and apoptosis-positive cells were observed in the selenium-deficient placenta. Our results suggested that maternal selenium deficiency impaired placental proliferation, induced autophagy dysfunction and apoptosis via increasing oxidative stress, and the Akt/mechanistic target of rapamycin (mTOR) pathway involved in this process. This study revealed a novel mechanism by which maternal selenium deficiency caused impairment of the placenta.

Th1/Th2 imbalance and heat shock protein mediated inflammatory damage triggered by manganese via activating NF-κB pathway in chicken nervous system in vivo and in vitro

Manganese (Mn) is a ubiquitous heavy metal pollutant in environment, and excess Mn can damage nervous system of humans and animals. However, molecular mechanism of Mn-induced poultry neurotoxicity on inflammatory injury is still not fully clear. Thus, the purpose of the conducted research was to explore molecular mechanism of inflammatory injury caused by Mn in chicken nervous system. Two Mn poisoning models were established in vivo and in vitro. One hundred and eighty chickens were randomly separated into four groups. One control group was raised drinking water and standard diet. Three Mn groups were raised drinking water, and the standard diet supplemented with three different concentrations of MnCl2 ∙ 4H2O. There were 45 birds and 3 replicates in each group. Neurocytes from chicken embryos were cultured in mediums without and with six different concentrations of MnCl2 ∙ 4H2O in vitro. Our experiments showed that excess Mn caused cerebral histomorphological structure alternations and damage, and increased the expressions (P < 0.05) of inflammation-related factor NF-κB, TNF-α, iNOS, COX-2, and PTGEs in vivo and in vitro, meaning that excess Mn caused inflammatory damage and inflammatory response in chicken nervous system. Moreover, there were an upregulated IFN-γ mRNA expression and a downregulated IL-4 mRNA expression (P < 0.05) in bird cerebra and embryonic neurocytes after exposure to Mn, indicating that Mn exposure caused Th1/Th2 imbalance and immunosuppression. Additionally, in our research, the elevation (P < 0.05) of five HSPs (HSP27, HSP40, HSP60, HSP70, and HSP90) was found, suggesting that HSPs participated molecular mechanism of Mn stress. In addition, the inflammatory toxicity of Mn to chicken nervous system was time- and dose-dependent. Taken all together, our findings indicated that Th1/Th2 imbalance and HSPs mediated Mn-caused inflammatory injury via NF-κB pathway in chicken nervous system in vivo and in vitro.

Dietary Selenium Regulates microRNAs in Metabolic Disease: Recent Progress

Selenium (Se) is an essential element for the maintenance of a healthy physiological state. However, due to environmental and dietary factors and the narrow safety range of Se, diseases caused by Se deficiency or excess have gained considerable traction in recent years. In particular, links have been identified between low Se status, cognitive decline, immune disorders, and increased mortality, whereas excess Se increases metabolic risk. Considerable evidence has suggested microRNAs (miRNAs) regulate interactions between the environment (including the diet) and genes, and play important roles in several diseases, including cancer. MiRNAs target messenger RNAs to induce changes in proteins including selenoprotein expression, ultimately generating disease. While a plethora of data exists on the epigenetic regulation of other dietary factors, nutrient Se epigenetics and especially miRNA regulated mechanisms remain unclear. Thus, this review mainly focuses on Se metabolism, pathogenic mechanisms, and miRNAs as key regulatory factors in Se-related diseases. Finally, we attempt to clarify the regulatory mechanisms underpinning Se, miRNAs, selenoproteins, and Se-related diseases.