Alzheimer's disease is a neurodegenerative disorder characterized by extracellular deposition of amyloid‐β (Aβ) peptide and hyperphosphorylation of Tau protein, which ultimately leads to the ...formation of intracellular neurofibrillary tangles and cell death. Increasing evidence indicates that genistein, a soy isoflavone, has neuroprotective effects against Aβ‐induced toxicity. However, the molecular mechanisms involved in its neuroprotection are not well understood. In this study, we have established a neuronal damage model using retinoic‐acid differentiated SH‐SY5Y cells treated with different concentrations of Aβ25–35 to investigate the effect of genistein against Aβ‐induced cell death and the possible involvement of protein kinase B (PKB, also termed Akt), glycogen synthase kinase 3β (GSK‐3β), and Tau as an underlying mechanism to this neuroprotection. Differentiated SH‐SY5Y cells were pre‐treated for 24 hr with genistein (1 and 10 nM) and exposed to Aβ25–35 (25 μM), and we found that genistein partially inhibited Aβ induced cell death, primarily apoptosis. Furthermore, the protective effect of genistein was associated with the inhibition of Aβ‐induced Akt inactivation and Tau hyperphosphorylation. These findings reinforce the neuroprotective effects of genistein against Aβ toxicity and provide evidence that its mechanism may involve regulation of Akt and Tau proteins.
Skeletal muscle synthesizes, stores, and releases body L-glutamine (GLN). Muscle atrophy due to disabling diseases triggers the activation of proteolytic and pro-apoptotic cell signaling, thus ...impairing the body's capacity to manage GLN content. This situation has a poor therapeutic prognosis.
Evaluating if oral GLN supplementation can attenuate muscle wasting mediated by elevated plasma cortisol and activation of caspase-3, p38MAPK, and FOXO3a signaling pathways in soleus and gastrocnemius muscles of rats submitted to 14-day bilateral hindlimbs immobilization.
Animals were randomly distributed into six groups: non-immobilized rats (Control), control orally supplemented with GLN (1 g kg
) in solution with L-alanine (ALA: 0.61 g kg
; GLN+ALA), control orally supplemented with dipeptide L-alanyl-L-glutamine (DIP; 1.49 g kg
), hindlimbs immobilized rats (IMOB), IMOB orally GLN+ALA supplemented (GLN+ALA-IMOB), and IMOB orally DIP supplemented (DIP-IMOB). Plasma and muscle GLN concentration, plasma cortisol level, muscle caspase-3 activity, muscle p38MAPK and FOXO3a protein content (total and phosphorylated forms), and muscle cross-sectional area (CSA) were measured.
Compared to controls, IMOB rats presented: a) increased plasma cortisol levels; b) decreased plasma and muscle GLN concentration; c) increased muscle caspase-3 activity; d) increased total and phosphorylated p38MAPK protein content; e) increased FOXO3a and decreased phosphorylated FOXO3a protein content; f) reduced muscle weight and CSA befitting to atrophy. Oral supplementation with GLN+ALA and DIP was able to significantly attenuate these effects.
These findings attest that oral GLN supplementation in GLN+ALA solution or DIP forms attenuates rats' skeletal muscle mass wasting caused by disuse-mediated muscle atrophy.
Introduction
Cardiovascular diseases (CVD) have been associated with high exposure to fine particulate air pollutants (PM
2.5
). Alveolar macrophages are the first defense against inhaled particles. ...As soon as they phagocytize the particles, they reach an inflammatory phenotype, which affects the surrounding cells and associates with CVD. Not coincidentally, CVD are marked by a depleted heat shock response (HSR), defined by a deficit in inducing 70-kDa heat shock protein (HSP70) expression during stressful conditions. HSP70 is a powerful anti-inflammatory chaperone, whose reduced levels trigger a pro-inflammatory milieu, cellular senescence, and a senescence-associated secretory phenotype (SASP). However, whether macrophage senescence is the main mechanism by which PM
2.5
propagates low-grade inflammation remains unclear.
Objective and design
In this article, we review evidence supporting that chronic exposure to PM
2.5
depletes HSR and determines the ability to solve the initial stress.
Results and Discussion
When exposed to PM
2.5
, macrophages increase the production of reactive oxygen species, which activate nuclear factor-kappa B (NF-κB). NF-κB is naturally a pro-inflammatory factor that drives prostaglandin E2 (PGE2) synthesis and causes fever. PGE2 can be converted into prostaglandin A2, a powerful inducer of HSR. Therefore, when transiently activated, NF-κB can trigger the anti-inflammatory response through negative feedback, by inducing HSP70 expression. However, when chronically activated, NF-κB heads a set of pathways involved in mitochondrial dysfunction, endoplasmic reticulum stress, unfolded protein response, inflammasome activation, and apoptosis. During chronic exposure to PM
2.5
, cells cannot properly express sirtuin-1 or activate heat shock factor-1 (HSF-1), which delays the resolution phase of inflammation. Since alveolar macrophages are the first immune defense against PM
2.5
, we suppose that the pollutant impairs HSR and, consequently, induces cellular senescence. Accordingly, senescent macrophages change its secretory phenotype to a more inflammatory one, known as SASP. Finally, macrophages’ SASP would propagate the systemic inflammation, leading to endothelial dysfunction and atherosclerosis.
The phytoalexin Resveratrol (3,5,4′-trihydroxystilbene; RSV) has been related to numerous beneficial effects on health by its cytoprotection and chemoprevention activities. Liver fibrosis is ...characterized by the extracellular matrix accumulation after hepatic injury and can lead to cirrhosis. Hepatic stellate cells (HSC) play a crucial role during fibrogenesis and liver wound healing by changing their quiescent phenotype to an activated phenotype for protecting healthy areas from damaged areas. Strategies on promoting the activated HSC death, the quiescence return or the cellular activation stimuli decrease play an important role on reducing liver fibrosis. Here, we evaluated the RSV effects on some markers of activation in GRX, an HSC model. We further evaluated the RSV influence in the ability of GRX on releasing inflammatory mediators. RSV at 1 and 10 µM did not alter the protein content of α-SMA, collagen I and GFAP; but 50 µM increased the content of these activation-related proteins. Also, RSV did not change the myofibroblast-like morphology of GRX. Interestingly, RSV at 10 and 50 µM decreased the GRX migration and collagen-I gel contraction. Finally, we showed that RSV triggered the increase in the TNF-α and IL-10 content in culture media of GRX while the opposite occurred for the IL-6 content. Altogether, these results suggested that RSV did not decrease the activation state of GRX and oppositely, triggered a pro-activation effect at the 50 µM concentration. However, despite the increase of TNF- α in culture media, these results on IL-6 and IL-10 secretion were in accordance with the anti-inflammatory role of RSV in our model.
Ischemic stroke is a major cause of death and disability, intensely demanding innovative and accessible therapeutic strategies. Approaches presenting a prolonged period for therapeutic intervention ...and new treatment administration routes are promising tools for stroke treatment. Here, we evaluated the potential neuroprotective properties of nasally administered human adipose tissue mesenchymal stem cell (hAT-MSC)-derived extracellular vesicles (EVs) obtained from healthy individuals who underwent liposuction. After a single intranasal EV (200 µg/kg) administered 24 h after a focal permanent ischemic stroke in rats, a higher number of EVs, improvement of the blood-brain barrier, and re-stabilization of vascularization were observed in the recoverable peri-infarct zone, as well as a significant decrease in infarct volume. In addition, EV treatment recovered long-term motor (front paws symmetry) and behavioral impairment (short- and long-term memory and anxiety-like behavior) induced by ischemic stroke. In line with these findings, our work highlights hAT-MSC-derived EVs as a promising therapeutic strategy for stroke.
Caveolin‐1 (Cav‐1) expression is increased in hepatic stellate cells (HSC) upon liver cirrhosis and it functions as an integral membrane protein of lipid rafts and caveolae that regulates and ...integrates multiple signals as a platform. This study aimed to evaluate the role of Cav‐1 in HSC. Thus, the effects of exogenous expression of Cav‐1 in GRX cells, a model of activated HSC, were determined. Here, we demonstrated through evaluating well‐known HSC activation markers – such as α‐smooth muscle actin, collagen I, and glial fibrillary acidic protein – that up regulation of Cav‐1 induced GRX to a more activated phenotype. GRXEGFP‐Cav1 presented an increased migration, an altered adhesion pattern, a reorganization f‐actin cytoskeleton, an arrested cell cycle, a modified cellular ultrastructure, and a raised endocytic flux. Based on this, GRX
EGFP‐Cav1 represents a new cellular model that can be an important tool for understanding of events related to HSC activation. Furthermore, our results reinforce the role of Cav‐1 as a molecular marker of HSC activation.
1‐ Exogenous expression of caveolin‐1 (Cav‐1) leads hepatic stellate cells (HSC) to more activated phenotype 2‐ GRXEGFP‐Cav1 cell line is a first‐rate tool for liver fibrosis studying 3‐ Cav‐1 is a potential molecular marker for HSC activation.
Glioblastoma is the most frequent and malignant brain tumor. Treatment includes chemotherapy with temozolomide concomitant with surgical resection and/or irradiation. However, a number of cases are ...resistant to temozolomide, as well as the human glioblastoma cell line U138-MG. We investigated doxazosin's (an antihypertensive drug) activity against glioblastoma cells (C6 and U138-MG) and its neurotoxicity on primary astrocytes and organoptypic hippocampal cultures. For this study, the following methods were used: citotoxicity assays, flow cytometry, western-blotting and confocal microscopy. We showed that doxazosin induces cell death on C6 and U138-MG cells. We observed that doxazosin's effects on the PI3K/Akt pathway were similar as LY294002 (PI3K specific inhibitor). In glioblastoma cells treated with doxasozin, Akt levels were greatly reduced. Upon examination of activities of proteins downstream of Akt we observed upregulation of GSK-3β and p53. This led to cell proliferation inhibition, cell death induction via caspase-3 activation and cell cycle arrest at G0/G1 phase in glioblastoma cells. We used in this study Lapatinib, a tyrosine kinase inhibitor, as a comparison with doxazosin because they present similar chemical structure. We also tested the neurocitotoxicity of doxazosin in primary astrocytes and organotypic cultures and observed that doxazosin induced cell death on a small percentage of non-tumor cells. Aggressiveness of glioblastoma tumors and dismal prognosis require development of new treatment agents. This includes less toxic drugs, more selective towards tumor cells, causing less damage to the patient. Therefore, our results confirm the potential of doxazosin as an attractive therapeutic antiglioma agent.
In the present report 15day-old Wistar rats were injected with 0.3μmol of diphenyl ditelluride (PhTe)2/kg body weight and parameters of neurodegeneration were analyzed in slices from striatum 6days ...afterwards. We found hyperphosphorylation of intermediate filament (IF) proteins from astrocyte (glial fibrillary acidic protein—GFAP and vimentin) and from neuron (low-, medium- and high molecular weight neurofilament subunits: NF-L, NF-M and NF-H, respectively) and increased MAPK (Erk, JNK and p38MAPK) as well as PKA activities. The treatment induced reactive astrogliosis in the striatum, evidenced by increased GFAP and vimentin immunocontent as well as their mRNA overexpression. Also, (PhTe)2 significantly increased the propidium iodide (PI) positive cells in NeuN positive population without altering PI incorporation into GFAP positive cells, indicating that in vivo exposure to (PhTe)2 provoked neuronal damage. Immunohistochemistry showed a dramatic increase of GFAP staining characteristic of reactive astrogliosis. Moreover, increased caspase 3 in (PhTe)2 treated striatal slices suggested apoptotic cell death. (PhTe)2 exposure decreased Akt immunoreactivity, however phospho-GSK-3-β (Ser9) was unaltered, suggesting that this kinase is not directly implicated in the neurotoxicity of this compound. Therefore, the present results shed light into the mechanisms of (PhTe)2-induced neurodegeneration in rat striatum, evidencing a critical role for the MAPK and Akt signaling pathways and disruption of cytoskeletal homeostasis, which could be related with apoptotic neuronal death and astrogliosis.
► Diphenyl ditelluride causes apoptotic neuronal death in the striatum of young rats. ► Diphenyl ditelluride causes reactive astrogliosis in the striatum of rats. ► Diphenyl ditelluride disrupts the homeostasis of the cytoskeleton of the striatum. ► The actions of diphenyl ditelluride are mediated by MAPK and Akt signaling pathways.
Resveratrol has been the focus of numerous studies reporting opposite effects that depend on its concentration. The GRX is an activated hepatic stellate cells model used to study liver fibrosis ...development and resolution. We recently showed that GRX treatment with RSV (0.1–50 µM) for 24 h triggered dose-dependent pro-oxidant effects, resulting in cytotoxicity and cell damage only at the highest concentration. Here, we evaluated whether the pro-oxidant effect of resveratrol treatment is accompanied by alterations on the GRX mitochondrial metabolism, and whether the concomitantly autophagy/mitophagy induction can influence on cell death or survival. We demonstrated that all concentrations of resveratrol promoted an increase of GRX cell death signals, altering the mitochondrial dynamics and function. Cells treated with all resveratrol concentrations presented higher autophagy/mitophagy features, but only treatments with 1 and 10 µM of resveratrol-induced mitochondrial biogenesis. Since cell damage was higher and there was no mitochondrial biogenesis in GRX treated with 50 µM of resveratrol, we suggest that these cells failed to remove and replace all damaged mitochondria. In conclusion, the cytotoxic effect of resveratrol that effectively promotes cell death could be related to the interrelation between the concomitant induction of apoptosis, autophagy/mitophagy and mitochondrial biogenesis in GRX.
Abstract
Background:
Growing evidence supports the existence of neurobiological trait abnormalities in individuals at genetic risk for bipolar disorder. The aim of this study was to examine potential ...differences in brain-derived neurotrophic factor, cytokines, oxidative stress, and telomere length markers between patients with bipolar disorder, their siblings, and healthy controls.
Methods:
Thirty-six patients with bipolar disorder type I, 39 siblings, and 44 healthy controls were assessed. Serum levels of brain-derived neurotrophic factor, interleukin-6, interleukin-10, tumor necrosis factor-α, C-C motif chemokine 11, C-C motif chemokine 24, and 3-nitrotyrosine were measured, as were the activities of glutathione peroxidase, glutathione reductase, and glutathione S-transferase. Telomere length (T/S ratio) was measured using quantitative polymerase chain reaction.
Results:
Telomere length was different between the 3 groups (P = .041) with both patients and siblings showing a shorter T/S ratio compared with healthy controls. Patients showed increased levels of interleukin-6 (P = .005) and interleukin-10 (P = .002) compared with controls as well as increased levels of interleukin-6 (p = 0.014) and CCL24 (P = .016) compared with their siblings. C-C motif chemokine 11 levels were increased in siblings compared with controls (P = .015), and a similar tendency was found in patients compared with controls (P = .045). Glutathione peroxidase activity was decreased in patients compared with controls (P = .006) and siblings (P = .025). No differences were found for the other markers.
Conclusions:
The present results suggest that unaffected siblings may present accelerated aging features. These neurobiological findings may be considered as endophenotypic traits. Further prospective studies are warranted.
PDF
