Isobavachalcone attenuates myotube atrophy induced by TNF-α through muscle atrophy F-box signaling and the nuclear factor erythroid 2-related factor 2 cascade

Skeletal muscle atrophy is a condition characterized by damaged muscle fibers and reduced numbers of muscle cells due to various causes. Muscle atrophy is associated with chronic diseases, such as heart failure, diabetes, and aging-related diseases. Isobavachalcone (IBC) is a flavonoid found in various foods and natural products, and studies have investigated its diverse effects, including its neuroprotective and anticancer effects. However, no studies have evaluated the effects of IBC on muscle atrophy. Thus, in this study, we assessed the effects of IBC on prevention of muscle atrophy. To evaluate the preventive effects of IBC on muscle atrophy, we used C2C12 myoblasts and induced muscle atrophy by tumor necrosis factor (TNF)-α. IBC regulated the expression levels of muscle atrophy F-box and muscle RING finger-1 in response to damaged muscle cells, thereby restoring the expression of myosin heavy chain and myogenin. Moreover, IBC regulated the phosphorylation of the nuclear factor-κB and p38 and upregulated the expression of nuclear factor erythroid 2-related factor 2 and heme oxygenase-1, which are involved in regulating oxidative stress. Our results indicated that IBC acted to relieve TNF-α-induced skeletal muscle atrophy by regulating the factors related to inflammation and oxidative stress.

Augmented NRF2 activation protects adult sickle mice from lethal acute chest syndrome

Acute chest syndrome (ACS) mortality in sickle cell disease (SCD) rises sharply in young adult patients and mechanism-based prophylaxis is lacking. In SCD, haem oxygenase-1 (HO-1) declines with age and ACS is associated with low HO-1. To test if enhanced HO-1 can reduce ACS mortality, young SCD mice were treated with D3T (3H-1,2-dithiole-3-thione), an activator of nuclear-factor erythroid 2 like 2, which controls HO-1 expression, for 3 months. Following haem-induced ACS, all vehicle-treated mice succumbed to severe lung injury, while D3T-treated mice had significantly improved survival. Blocking HO-1 activity abrogated the D3T effect. Thus HO-1 may be targeted to reduce ACS severity in adult patients.

Nuclear Factor Erythroid 2 Regulates Human HSC Self-Renewal and T Cell Differentiation by Preventing NOTCH1 Activation

Nuclear factor erythroid-derived 2 (NF-E2) has been associated with megakaryocyte maturation and platelet production. Recently, an increased in NF-E2 activity has been implicated in myeloproliferative neoplasms. Here, we investigate the role of NF-E2 in normal human hematopoiesis. Knockdown of NF-E2 in the hematopoietic stem and progenitor cells (HSPCs) not only reduced the formation of megakaryocytes but also drastically impaired hematopoietic stem cell activity, decreasing human engraftment in immunodeficient (NSG) mice. This phenotype is likely to be related to both increased cell proliferation (p21-mediated) and reduced Notch1 protein expression, which favors HSPC differentiation over self-renewal. Strikingly, although NF-E2 silencing in HSPCs did not affect their myeloid and B cell differentiation in vivo, it almost abrogated T cell production in primary hosts, as confirmed by in vitro studies. This effect is at least partly due to Notch1 downregulation in NF-E2-silenced HSPCs. Together these data reveal that NF-E2 is an important driver of human hematopoietic stem cell maintenance and T lineage differentiation.

Oleanolic acid protects against diabetic cardiomyopathy via modulation of the nuclear factor erythroid 2 and insulin signaling pathways

Oleanolic acid (OL) is a pentacyclic triterpene compound used for the treatment of hepatitis, liver fibrosis and liver cirrhosis. In China, there is no published research on the effect or biological utilization of OL on liver diseases. The aim of the present study was to investigate the protective effects of OL against diabetic cardiomyopathy and its possible mechanism. A rat model of diabetes was established using streptozotocin and the effect of OL on diabetic cardiomyopathy (DCM) was evaluated. The results demonstrated that OL significantly reversed the DCM-induced changes to body weight, heart rate, echocardiography and hemodynamics, phosphorylated-glycogen synthase (GS) and glycogen phosphorylase (GP) activity in diabetic rats (all P<0.01). Treatment of diabetic rats with OL significantly inhibited oxidative stress and activated heme oxygenase (HO)-1/nuclear factor erythroid 2 (Nrf2) signaling in a rat model of diabetes (both P<0.01). The results of the present study indicate that OL protects against DCM through the HO-1/Nrf2 and insulin modulating GS/GP signaling pathways.

DHA sensitizes FaO cells to tert-BHP-induced oxidative effects. Protective role of EGCG

The excessive production of reactive oxygen species has been implicated in several pathologies, such as atherosclerosis, obesity, hypertension and insulin resistance. Docosahexaenoic acid (DHA) may protect against the above mentioned diseases, but paradoxically the main DHA treated pathologies are also associated with increased ROS levels. Therefore, the aim of this study was to explore if in vitro DHA supplementation may increase the sensitivity of cells to tert-BHP induced oxidative stress, and if the green tea polyphenol epigallocatechin-3-gallate (EGCG) is able to correct such detrimental effect. We found that DHA-enriched cells exacerbate ROS generation, decrease cell viability and increase Nrf2 nuclear translocation and HO-1 expression. Interestingly, cellular EGCG is able to counteract oxidative damage from either tert-BHP or DHA-enriched cells. In consequence, our results suggest that in a ROS enriched environment DHA could not always be beneficial for cells and can be considered a double-edged sword in terms of its benefits vs. risks. In this sense, our results propose that the supplementation with potent antioxidant molecules could be an appropriate strategy to reduce the risks related with the DHA supplementation in an oxidative stress-associated condition.