Oxidative stress causes mitochondrial dysfunction and heart failure through unknown mechanisms. Cardiolipin (CL), a mitochondrial membrane phospholipid required for oxidative phosphorylation, plays a pivotal role in cardiac function. The onset of age-related heart diseases is characterized by aberrant CL acyl composition that is highly sensitive to oxidative damage, leading to CL peroxidation and mitochondrial dysfunction. Here we report a key role of ALCAT1, a lysocardiolipin acyltransferase that catalyzes the synthesis of CL with a high peroxidation index, in mitochondrial dysfunction associated with hypertrophic cardiomyopathy. We show that ALCAT1 expression was potently upregulated by the onset of hyperthyroid cardiomyopathy, leading to oxidative stress and mitochondrial dysfunction. Accordingly, overexpression of ALCAT1 in H9c2 cardiac cells caused severe oxidative stress, lipid peroxidation, and mitochondrial DNA (mtDNA) depletion. Conversely, ablation of ALCAT1 prevented the onset of T4-induced cardiomyopathy and cardiac dysfunction. ALCAT1 deficiency also mitigated oxidative stress, insulin resistance, and mitochondrial dysfunction by improving mitochondrial quality control through upregulation of PINK1, a mitochondrial GTPase required for mitochondrial autophagy. Together, these findings implicate a key role of ALCAT1 as the missing link between oxidative stress and mitochondrial dysfunction in the etiology of age-related heart diseases.

Background: MARK4 is a member of the AMPK-related kinase family whose biological function remains elusive. Results: Using mice with targeted deletion of mark4, we identified a key role of the kinase in regulating glucose and energy homeostasis. Conclusion: MARK4 is required for energy homeostasis by regulating satiety and the metabolic rate in rodents. Significance: These data provide a key insight for targeting MARK4 for the treatment of obesity.

Ischemic stroke is a clinically common cerebrovascular disease whose main risks include necrosis, apoptosis and cerebral infarction, all caused by cerebral ischemia and reperfusion (I/R). Ischemia and reperfusion-induced injury or apoptosis inhibition in human brain tissue may exert an irreplaceable protective effect on ischemic nerves. This process has particular significance for the treatment of stroke patients. However, the development of neuroprotective drugs remains challenging. Radix Scrophulariae, traditionally considered a valuable medicine, has been discovered to have neuroprotective effects. To explore the neuroprotective effects of an aqueous extract of Radix Scrophulariae (RSAE) on cerebral ischemia/reperfusion and their underlying mechanisms, oxygen-glucose deprivation and reperfusion (OGD/R)-induced PC12 cells were used, and a middle cerebral artery occlusion/reperfusion (MCAO/R) mouse model was established. In vitro results showed that 12.5 μg/mL RSAE markedly improved cell viability; inhibited LDH leakage; increased SOD, GSH-Px and CAT enzyme activity; stabilized the mitochondrial membrane potential; and reduced OGD-induced cell injury and apoptosis. Additionally, in vivo results preliminarily suggested that in MCAO/R model mice, RSAE treatments attenuated infarct volume; reduced brain water content and nitric oxide (NO) and malondialdehyde (MDA) concentrations; inhibited I/R-induced neurological deficits; reduced the levels of lactate dehydrogenase (LDH) leakage release; improved antioxidant capacity by upregulating SOD, GSH-Px and CAT enzyme activity; and reduced neuronal apoptosis, necrosis and loss of neurons. Moreover, it was found that RSAE upregulated the expression of Bcl-2 and downregulated the expression of Bax. In addition, the phosphorylation levels of MAPK signal pathways were elucidated via western blot analysis and immunohistochemical evaluation. In summary, this study investigated the neuroprotective effects and potential mechanisms of RSAE on focal cerebral I/R injury in mice. Radix Scrophulariae has been previously identified as a potential neuroprotective natural plant. Hence, our results may offer insight into discovering new active compounds or drugs for the treatment of ischemic stroke. Many new natural active chemicals in this extract may be discovered by chemical separation and identification and may provide new insights into therapeutic targets in stroke patients.

Mark4 promotes adipogenesis in 3T3-L1 adipocytes by activating the JNK1 and inhibiting the p38MAPK pathway, and triggers apoptosis by activating the JNK1 pathway. We conclude that anti-Mark4 therapy targetted to inhibit lipid accumulation and apoptosis of adipocytes shows potential as a novel therapeutic strategy for treatment of obesity-associated metabolic complications.

SummaryThis study was conducted to evaluate the influence of back-fat thickness (BF), at mating of sows, on the maternal and newborn circulating lipids, expression of placental fatty acids (FA) transporters and lipid accumulation in placenta. Full-term placentas were obtained by vaginal delivery from BFI (9-14 mm; n = 37), BFII (15-19 mm; n = 43) and BFIII (20-27 mm; n = 38) sows according to BF at mating, and frozen placental sections were analysed for fat accumulation. Blood samples were collected from the sows of day 105 pregnancy and from cord blood at delivery. mRNA and protein expression levels were evaluated with real-time RT-PCR and Western blotting.Our results demonstrated that BFII females had significantly increased litter weight and placental efficiency, decreased maternal triglyceride (TG) and non-esterified fatty acids (NEFA) levels, decreased maternal IL-6, TNFα and leptin levels compared to BFIII females (p < .05). BFIII sows were associated with significantly decreased newborn TG levels, increased newborn glucose, IL-6 and TNFα levels compared to BFI or BFII sows (p < .05). BFI and BFII females had significantly decreased placental TG, NEFA and cholesterol (CHOL) contents compared to BFIII females (p < .05). Moreover, decreased CD36, FATP1, FABP4, and FABP1 mRNA and protein and FATP4 protein expression, and increased LPL activity were also observed in BFIII group compared with BFII group (p < .05). PPARγ mRNA and protein and lipogenic genes such as SREBP-1c, ACSL1, ACCα, FAS and SCD mRNA expression were downregulated or upregulated, respectively, in the placentas of BFIII sows compared to BFI or BFII sows (p < .05). Overall, this study demonstrated that there is no advantage, in terms of litter live size, litter weight and placental FA transport and metabolism, in performing the mating of sows with BF>19 mm. K E Y W O R D Sfatty acids, LPL, obesity, pig, placenta, PPAR

This study aimed to characterize the full-length cDNA of MARK4 in Sus scrofa, and evaluated its potential role in the regulation of lipid accumulation in pig placental trophoblasts and analyzed signaling pathways involved, thereby providing insights into mechanisms for placental lipotoxicity induced by excessive back-fat during pregnancy of sows. The cDNA obtained with 5′ and 3′ RACE amplification covered 3216 bp with an open reading frame of 2259 bp encoding 752 amino acids. Multiple alignments and phylogenetic analysis revealed MARK4 protein of Sus scrofa had a high homology (95%–99%) to that of other higher vertebrates. After transfection, enhanced MARK4 significantly promoted lipogenesis in pig trophoblasts, as evidenced by accelerated lipid accumulation and consistently increased mRNA expressions of lipogenic genes DGAT1, LPIN1, LPIN3, LPL, PPARδ and SREBP-1c. Meanwhile, PPARγ remarkably inhibited the stimulating effect of MARK4 on non-receptor-mediated lipid accumulation in trophoblasts. Further analyses revealed WNT signaling enhanced lipid accumulation and activation of MARK4 in pig trophoblast cells. Finally, we demonstrated that WNT/β-catenin signal pathway is involved in MARK4 activated lipogenesis. These results suggest that MARK4 promotes lipid accumulation in porcine placental trophoblasts and can be considered as a potential regulator of lipotoxicity associated with maternal obesity in the pig placenta.

The aim of this study was to determine the effect of excessive back-fat (BF) of sows on placental oxidative stress, ATP generation, mitochondrial alterations in content and structure, and mitochondrial function in isolated trophoblasts. Placental tissue was collected by vaginal delivery from BFI (15–20 mm, n = 10) and BFII (21–27 mm, n = 10) sows formed according to BF at mating. Our results demonstrated that excessive back-fat contributed to augmented oxidative stress in term placenta, as evidenced by excessive production of ROS, elevated protein carbonylation, and reduced SOD, GSH-PX, and CAT activities (p < 0.05). Indicative of mitochondrial dysfunction, reduced mitochondrial respiration in cultured trophoblasts was linked to decreased ATP generation, lower mitochondrial Complex I activity and reduced expression of electron transport chain subunits in placenta of BFII sows (p < 0.05). Meanwhile, we observed negative alterations in mitochondrial biogenesis and structure in the placenta from BFII group (p < 0.05). Finally, our in vitro studies showed lipid-induced ROS production resulted in mitochondrial alterations in trophoblasts, and these effects were blocked by antioxidant treatment. Together, these data reveal that excessive back-fat aggravates mitochondrial injury induced by increased oxidative stress in pig term placenta, which may have detrimental consequences on placental function and therefore impaired fetal growth and development.

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