Preventive effects of crocin on neuronal damages induced by D-galactose through AGEs and oxidative stress in human neuroblastoma cells (SH-SY5Y)

Alpha-mangostin decreases high glucose-induced damage on human umbilical vein endothelial cells by increasing autophagic protein expression

Objectives

Diabetes is a chronic disorder that occurs as a result of impaired glucose metabolism. In hyperglycaemic states, the balance between oxidative stress and antioxidant enzymes is disrupted leading to oxidative damage and cell death. In addition, impaired autophagy leads to the storage of dysfunctional proteins and cellular organelles in the cell. Hence, the cytoprotective function of autophagy may be disrupted by high glucose conditions. Alpha-mangostin (A-MG) is an essential xanthone purified from the mangosteen fruit. The different pharmacological benefits of alpha-mangostin, including antioxidant, anti-obesity, and antidiabetic, were demonstrated.

Materials and Methods

We evaluated the protective influence of A-MG on autophagic response impaired by high concentrations of glucose in human umbilical vein endothelial cells (HUVECs). The HUVECs were treated with various glucose concentrations (5-60 mM) and A-MG (1.25-10 μM) for three days. Then, HUVECs were treated with 60 mM of glucose+2.5 μM of A-MG to measure viability, ROS, and NO content. Finally, the levels of autophagic proteins including LC3, SIRT1, and beclin 1 were evaluated by western blot.

Results

The results expressed that high glucose condition (60 mM) decreased viability and increased ROS and NO content in HUVECs. In addition, LC3, SIRT1, and beclin 1 protein levels declined when HUVECs were exposed to the high concentration of glucose. A-MG reversed these detrimental effects and elevated autophagic protein levels.

Conclusion

Our data represent that A-MG protects HUVECs against high glucose conditions by decreasing ROS and NO generation as well as increasing the expression of autophagy proteins.

Melamine Exacerbates Neurotoxicity in D-Galactose-Induced Neuronal SH-SY5Y Cells

Numerous studies have depicted the role of diet and environmental toxins in aging. Melamine (Mel) is a globally known notorious food adulterant, and its toxicity has been shown in several organs including the brain. However, till now, there are no reports regarding Mel neurotoxicity in aging neurons. So, this study examined the in vitro neurotoxicity caused by Mel in the D-galactose (DG)-induced aging model of neuronal SH-SY5Y cells. In the present study, the neuronal SH-SY5Y cells were treated with DG and Mel separately and in combination to assess the neurotoxicity potential using MTT assay and neurite length measurement. Further, the superoxide dismutase (SOD), catalase (CAT), and total antioxidant activities were evaluated followed by the determination of the intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and caspase3 (Casp3) activity. The cotreatment of Mel and DG in neuronal SH-SY5Y cells showed maximum cell death than the cells treated with DG or Mel individually and untreated control cells. The neurite length shrinkage and ROS production were maximum in the DG and Mel cotreated cells showing exacerbated toxicity of Mel. The activity of SOD, CAT, and total antioxidants was also found to be lowered in the cotreatment group (Mel + DG) than in Mel- or DG-treated and untreated cells. Further, the combined toxicity of Mel and DG also elevated the Casp3 activity more than any other group. This is the first study showing the increased neurotoxic potential of Mel in an aging model of neuronal SH-SY5Y cells which implicates that Mel consumption by the elderly may lead to increased incidences of neurodegeneration like Alzheimer's disease and Parkinson's disease.

Circulating Human Serum Metabolites Derived from the Intake of a Saffron Extract (Safr'InsideTM) Protect Neurons from Oxidative Stress: Consideration for Depressive Disorders

Increases in oxidative stress have been reported to play a central role in the vulnerability to depression, and antidepressant drugs may reduce increased oxidative stress in patients. Among the plants exerting anti-inflammatory and anti-oxidant properties, saffron, a spice derived from the flower of Crocus sativus, is also known for its positive effects on depression, potentially through its SSRI-like properties. However, the molecular mechanisms underlying these effects and their health benefits for humans are currently unclear. Using an original ex vivo clinical approach, we demonstrated for the first time that the circulating human metabolites produced following saffron intake (Safr’Inside^TM) protect human neurons from oxidative-stress-induced neurotoxicity by preserving cell viability and increasing BNDF production. In particular, the metabolites significantly stimulated both dopamine and serotonin release. In addition, the saffron’s metabolites were also able to protect serotonergic tone by inhibiting the expression of the serotonin transporter SERT and down-regulating serotonin metabolism. Altogether, these data provide new biochemical insights into the mechanisms underlying the beneficial impact of saffron on neuronal viability and activity in humans, in the context of oxidative stress related to depression.

SIRT 3 was involved in Lycium barbarum seed oil protection testis from oxidative stress: in vitro and in vivo analyses

CONTEXT

Lycium barbarum L. (Solanaceae) seed oil (LBSO) exerts LBSO exerts protective effects in the testis in vivo and in vitro via upregulating SIRT3.

OBJECTIVE

This study evaluates the effects and mechanism of LBSO in the d-galactose (d-gal)-induced ageing testis.

MATERIALS AND METHODS

Male Sprague Dawley (SD) rats (n = 30, 8-week-old) were randomly divided into three groups: LBSO group (n = 10) where rats received subcutaneous injection of d-gal at 125 mg/kg/day for 8 weeks and intragastric administration of LBSO at 1000 mg/kg/day for 4 weeks, ageing model group (n = 10) received 8-week-sunbcutaneous injection of d-gal, and control group (n = 10) with same administration of normal saline. Lentivirus had established TM4 cells with SIRT3 overexpression or silencing before LBSO intervened in vitro.

RESULTS

Treatment with LBSO, the levels of INHB and testosterone both increased, compared to ageing model. In vitro, we found the ED₅₀ of LBSO was 86.72 ± 1.49 and when the concentration of LBSO at 100 μg/mL to intervene TM4 cells, the number of cells increased from 8120 ± 676.2 to 15251 ± 1119, and the expression of SIRT3, HO-1, and SOD upregulated. However, HO-1 and SOD were dysregulated by silencing SIRT3. On the other hand, the expression of AMPK and PGC-1α upregulated as an effect of SIRT3 overexpression by lentivirus, meanwhile the same increasing trend of that being found in cells treated with LBSO, compared to control group.

DISCUSSION AND CONCLUSIONS

LBSO alleviated oxidative stress in d-gal-induced sub-acutely ageing testis and TM4 cells by suppressing the oxidative stress to mitochondria via SIRT3/AMPK/PGC-1α.

Effects of alpha-mangostin on memory senescence induced by high glucose in human umbilical vein endothelial cells

Objective(s):

Hyperglycemia induces cellular senescence in various body cells, such as vascular endothelial cells. Since the vessels are highly distributed in the body and nourish all tissues, vascular damages cause diabetes complications such as kidney failure and visual impairment. Alpha-mangostin is a xanthone found in mangosteen fruit with protective effects in metabolic syndrome and diabetes. This paper has investigated the protective effect of this xanthone against high glucose-induced memory senescence in human vascular endothelial cells (HUVECs) in the presence of metformin, as a positive control.

Materials and Methods:

To induce the memory senescence model, HUVECs, after three days incubation with high glucose, were incubated with normal glucose for another three days, and for whole six days, cells were treated with metformin (50 µM) or alpha-mangostin (1.25 µM). On the last day, cell viability by MTT assay, oxidative stress by fluorimetric assay, the number of senescent cells by SA beta-galactosidase staining kit, and secretory interleukin-6 by ELISA kit were measured. SIRT1 and P53 proteins were also evaluated by Western blotting.

Results:

Metformin and alpha-mangostin significantly increased cell viability, decreased reactive oxygen species, and senescence-associated beta-galactosidase in HUVECs incubated in metabolic memory condition. Generally, metabolic memory increased p53 and acetyl-P53 and decreased SIRT1 proteins in HUVECs, which were reversed by alpha-mangostin and metformin.

Conclusion:

These data exhibit that alpha-mangostin, comparable to metformin, protects endothelial cells against metabolic memory-induced senescence, which is likely via SIRT1.

L-histidine and L-carnosine exert anti-brain aging effects in D-galactose-induced aged neuronal cells

BACKGROUND/OBJECTIVES

Brain aging is a major risk factor for severe neurodegenerative diseases. Conversely, L-histidine and L-carnosine are known to exhibit neuroprotective effects. The aim of this study was to examine the potential for L-histidine, L-carnosine, and their combination to mediate anti-brain aging effects in neuronal cells subjected to D-galactose-induced aging.

MATERIALS/METHODS

The neuroprotective potential of L-histidine, L-carnosine, and their combination was examined in a retinoic acid-induced neuronal differentiated SH-SY5Y cell line exposed to D-galactose (200 mM) for 48 h. Neuronal cell proliferation, differentiation, and expression of anti-oxidant enzymes and apoptosis markers were subsequently evaluated.

RESULTS

Treatment with L-histidine (1 mM), L-carnosine (10 mM), or both for 48 h efficiently improved the proliferation, neurogenesis, and senescence of D-galactose-treated SH-SY5Y cells. In addition, protein expression levels of both neuronal markers (β tubulin-III and neurofilament heavy protein) and anti-oxidant enzymes, glutathione peroxidase-1 and superoxide dismutase-1 were up-regulated. Conversely, protein expression levels of amyloid β (1-42) and cleaved caspase-3 were down-regulated. Levels of mRNA for the pro-inflammatory cytokines, interleukin (IL)-8, IL-1β, and tumor necrosis factor-α were also down-regulated.

CONCLUSIONS

To the best of our knowledge, we provide the first evidence that L-histidine, L-carnosine, and their combination mediate anti-aging effects in a neuronal cell line subjected to D-galactose-induced aging. These results suggest the potential benefits of L-histidine and L-carnosine as anti-brain aging agents and they support further research of these amino acid molecules.

Anti-Inflammatory and Anti-Aging Evaluation of Pigment-Protein Complex Extracted from Chlorella Pyrenoidosa

Oxidative stress contributes to chronic inflammatory processes implicated in aging, referred to as “inflamm-aging.” In this study, the potential anti-inflammatory and anti-aging effects of a pigment–protein complex (PPC) from Chlorella pyrenoidosa were investigated using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and D-galactose (D-gal)-induced aging in a murine model. Results indicated that PPC inhibits the production of the inflammatory cytokines TNF-α and IL-6, and the inflammatory mediator nitric oxide (NO) in LPS-stimulated RAW 264.7 cells. It also protected mice from D-gal induced informatory aging by increasing the activity of the antioxidant enzyme, such as superoxide dismutase (SOD), inhibiting D-gal-induced NF-κB upregulation, and increasing PPARs expression in the brain and gut. The findings indicated that PPC has favorable anti-inflammatory and anti-aging properties, and could be useful in the treatment of acute inflammation and senescence diseases.