Nutritional Regulators of Bcl-xL in the Brain

Insights into nanoparticles-induced neurotoxicity and cope up strategies

Nanoparticle applications are becoming increasingly popular in fields such as photonics, catalysis, magnetics, biotechnology, manufacturing of cosmetics, pharmaceuticals, and medicines. There is still a huge pile of undermining information about the potential toxicity of these products to humans, which can be encountered by neuroprotective antioxidants and anti-inflammatory compounds. Nanoparticles can be administered using a variety of methods, including oronasal, topical applications, and enteral and parenteral routes of administration. There are different properties of these nanomaterials that characterize different pathways. Crossing of the blood-brain barrier, a direct sensory nerve-to-brain pathway whose barriers are bypassed, these checks otherwise prevent the nanoparticles from entering the brain. This inflicts damage to sensory neurons and receptors by nanoparticles that lead to neurotoxicity of the central nervous system. A number of routes make nanoparticles able to penetrate through the skin. Exposure by various routes to these nanoparticles can result in oxidative stress, and immune suppression triggers inflammatory cascades and genome-level mutations after they are introduced into the body. To out-power, these complications, plant-based antioxidants, essential oils, and dietary supplements can be put into use. Direct nanoparticle transport pathways from sensory nerves to the brain via blood have been studied grossly. Recent findings regarding the direct pathways through which nanoparticles cross the blood-brain barriers, how nanoparticles elicit different responses on sensory receptors and nerves, how they cause central neurotoxicity and neurodegeneration through sensory nerve routes, and the possible mechanisms that outcast these effects are discussed.

Alpha-Tocotrienol Enhances Arborization of Primary Hippocampal Neurons via Upregulation of Bcl-xL

Alpha-tocotrienol (α-TCT) is a member of the vitamin E family. It has been reported to protect the brain against various pathologies including cerebral ischemia and neurodegeneration. However, it is still unclear if α-TCT exhibits beneficial effects during brain development. We hypothesized that treatment with α-TCT improves intracellular redox homeostasis supporting normal development of neurons. We found that primary hippocampal neurons isolated from rat feti grown in α-TCT-containing media achieved greater levels of neurite complexity compared to ethanol-treated control neurons. Neurons were treated with 1 μM α-TCT for 3 weeks, and media were replaced with fresh α-TCT every week. Treatment with α-TCT increased α-TCT levels (26 pmol/mg protein) in the cells, whereas the control neurons did not contain α-TCT. α-TCT-treated neurons produced adenosine triphosphate (ATP) at a higher rate and increased ATP retention at neurites, supporting formation of neurite branches. Although treatment with α-TCT alone did not change neuronal viability, neurons grown in α-TCT were more resistant to death at maturity. We further found that messenger RNA and protein levels of B-cell lymphoma-extra large (Bcl-xL) are increased by α-TCT treatment without inducing posttranslational cleavage of Bcl-xL. Bcl-xL is known to enhance mitochondrial energy production, which improves neuronal function including neurite outgrowth and neurotransmission. Therefore α-TCT-mediated Bcl-xL upregulation may be the central mechanism of neuroprotection seen in the α-TCT-treated group. In summary, treatment with α-TCT upregulates Bcl-xL and increases ATP levels at neurites. This correlates with increased neurite branching during development and with protection of mature neurons against oxidative stress.

The Roles of the Ubiquitin-Proteasome System in the Endoplasmic Reticulum Stress Pathway

The endoplasmic reticulum (ER) is a highly dynamic organelle in eukaryotic cells, which is essential for synthesis, processing, sorting of protein and lipid metabolism. However, the cells activate a defense mechanism called endoplasmic reticulum stress (ER stress) response and initiate unfolded protein response (UPR) as the unfolded proteins exceed the folding capacity of the ER due to the environmental influences or increased protein synthesis. ER stress can mediate many cellular processes, including autophagy, apoptosis and senescence. The ubiquitin-proteasome system (UPS) is involved in the degradation of more than 80% of proteins in the cells. Today, increasing numbers of studies have shown that the two important components of UPS, E3 ubiquitin ligases and deubiquitinases (DUBs), are tightly related to ER stress. In this review, we summarized the regulation of the E3 ubiquitin ligases and DUBs in ER stress.

Anti-Apoptotic Effects of Carotenoids in Neurodegeneration

Apoptosis, programmed cell death type I, is a critical part of neurodegeneration in cerebral ischemia, Parkinson’s, and Alzheimer’s disease. Apoptosis begins with activation of pro-death proteins Bax and Bak, release of cytochrome c and activation of caspases, loss of membrane integrity of intracellular organelles, and ultimately cell death. Approaches that block apoptotic pathways may prevent or delay neurodegenerative processes. Carotenoids are a group of pigments found in fruits, vegetables, and seaweeds that possess antioxidant properties. Over the last several decades, an increasing number of studies have demonstrated a protective role of carotenoids in neurodegenerative disease. In this review, we describe functions of commonly consumed carotenoids including lycopene, β-carotene, lutein, astaxanthin, and fucoxanthin and their roles in neurodegenerative disease models. We also discuss the underlying cellular mechanisms of carotenoid-mediated neuroprotection, including their antioxidant properties, role as signaling molecules, and as gene regulators that alleviate apoptosis-associated brain cell death.

Dietary Antioxidants and Parkinson's Disease

Parkinson’s disease (PD) is a neurodegenerative disorder caused by the depletion of dopaminergic neurons in the basal ganglia, the movement center of the brain. Approximately 60,000 people are diagnosed with PD in the United States each year. Although the direct cause of PD can vary, accumulation of oxidative stress-induced neuronal damage due to increased production of reactive oxygen species (ROS) or impaired intracellular antioxidant defenses invariably occurs at the cellular levels. Pharmaceuticals such as dopaminergic prodrugs and agonists can alleviate some of the symptoms of PD. Currently, however, there is no treatment to halt the progression of PD pathology. Due to the nature of PD, a long and progressive neurodegenerative process, strategies to prevent or delay PD pathology may be well suited to lifestyle changes like dietary modification with antioxidant-rich foods to improve intracellular redox homeostasis. In this review, we discuss cellular and genetic factors that increase oxidative stress in PD. We also discuss neuroprotective roles of dietary antioxidants including vitamin C, vitamin E, carotenoids, selenium, and polyphenols along with their potential mechanisms to alleviate PD pathology.

A miR-1275 mimic protects myocardiocyte apoptosis by regulating the Wnt/NF-κB pathway in a rat model of myocardial ischemia-reperfusion-induced myocardial injury

This study evaluated the cardioprotective effects of a miR-1275 mimic in a rat model of myocardial ischemia-reperfusion (I/R)-induced myocardial injury (MI). Three groups of rats were established: a sham-operated group, a MI group and a MI+miR-1275 group pretreated for 1 week i.p. with a miR-1275 mimic at a concentration of 30 pmol/mL. MI was induced by I/R. The levels of myocardial enzymes in serum were estimated in all rats, together with haemodynamic functions. The effects of the miR-1275 mimic were determined based on the serum concentrations of inflammatory mediators in the treated vs. sham and MI rats. In addition, western blot assay and immunohistochemical analyses were performed to examine the effect of the miR-1275 mimic on the Wnt/NF-kB signalling pathway in MI rats. Treatment with the miR-1275 mimic attenuated the altered levels of myocardial enzymes and haemodynamic functions seen in MI rats. The myocardial infarct was smaller in rats treated with the miR-1275 mimic than in MI rats. The miR-1275 mimic also reduced myocardiocyte apoptosis and ameliorated the altered Wnt/KF-kB pathway. These results demonstrate the efficacy of the miR-1275 mimic in preventing myocardial I/R-induced MI in rats, by regulating the Wnt/NF-κB pathway.

Bcl-XL: A multifunctional anti-apoptotic protein

B-cell lymphoma-extra large (Bcl-X_L) is one of the anti-apoptotic proteins of the Bcl-2 family that is localized in the mitochondria. Bcl-X_L is one of the key regulators of apoptosis that can also regulate other important cellular functions. Bcl-X_L is overexpressed in many cancers, and its inhibitors have shown good therapeutic effects. Bcl-X_L interacts with Beclin 1, a key factor regulating autophagy. Bcl-X_L is essential for the survival of neurons and plays protective roles in neuronal injuries. It can promote the growth of neurons and the correct formation of neural networks, enhance synaptic plasticity, and control neurotoxicity. Bcl-X_L can also promote the transport of Ca²⁺ to mitochondria, increase the production of ATP, and improve metabolic efficiency. In addition, targeting Bcl-X_L has shown potential value in autoimmune diseases and aging. In this review, we summarize the functions of Bcl-X_L in cancer, autophagy, Ca²⁺ signaling, neuroprotection, neuronal growth and synaptic plasticity, energy metabolism, immunity, and senescence as revealed by investigations conducted in the past 10 years. Moreover, we list some inhibitors that have been developed based on the functions of Bcl-X_L.

Modulation of Nitric Oxide Synthases by Oxidized LDLs: Role in Vascular Inflammation and Atherosclerosis Development

The maintenance of physiological levels of nitric oxide (NO) produced by eNOS represents a key element for vascular endothelial homeostasis. On the other hand, NO overproduction, due to the activation of iNOS under different stress conditions, leads to endothelial dysfunction and, in the late stages, to the development of atherosclerosis. Oxidized LDLs (oxLDLs) represent the major candidates to trigger biomolecular processes accompanying endothelial dysfunction and vascular inflammation leading to atherosclerosis, though the pathophysiological mechanism still remains to be elucidated. Here, we summarize recent evidence suggesting that oxLDLs produce significant impairment in the modulation of the eNOS/iNOS machinery, downregulating eNOS via the HMGB1-TLR4-Caveolin-1 pathway. On the other hand, increased oxLDLs lead to sustained activation of the scavenger receptor LOX-1 and, subsequently, to NFkB activation, which, in turn, increases iNOS, leading to EC oxidative stress. Finally, these events are associated with reduced protective autophagic response and accelerated apoptotic EC death, which activates atherosclerotic development. Taken together, this information sheds new light on the pathophysiological mechanisms of oxLDL-related impairment of EC functionality and opens new perspectives in atherothrombosis prevention.

Leukemic IL-17RB signaling regulates leukemic survival and chemoresistance

Secreted proteins provide crucial signals that have been implicated in the development of acute myeloid leukemia (AML) in the bone marrow microenvironment. Here we identify aberrant expressions of inflammatory IL-17B and its receptor (IL-17RB) in human and mouse mixed lineage leukemia-rearranged AML cells, which were further increased after exposure to chemotherapy. Interestingly, silencing of IL-17B or IL-17RB led to significant suppression of leukemic cell survival and disease progression in vivo. Moreover, the IL-17B-IL-17RB axis protected leukemic cells from chemotherapeutic agent-induced apoptotic effects. Mechanistic studies revealed that IL-17B promoted AML cell survival by enhancing ERK, NF-κB phosphorylation, and the expression of antiapoptotic protein B-cell lymphoma 2, which were reversed by small-molecule inhibitors. Thus, the inhibition of the IL-17B-IL-17RB axis may be a valid strategy to enhance sensitivity and therapeutic benefit of AML chemotherapy.-Guo, H.-Z., Niu, L.-T., Qiang, W.-T., Chen, J., Wang, J., Yang, H., Zhang, W., Zhu, J., Yu, S.-H. Leukemic IL-17RB signaling regulates leukemic survival and chemoresistance.