Isochaihulactone protects PC12 cell against H(2)O(2) induced oxidative stress and exerts the potent anti-aging effects in D-galactose aging mouse model

The Role of Antioxidants in the Interplay between Oxidative Stress and Senescence

Cellular senescence is an irreversible state of cell cycle arrest occurring in response to stressful stimuli, such as telomere attrition, DNA damage, reactive oxygen species, and oncogenic proteins. Although beneficial and protective in several physiological processes, an excessive senescent cell burden has been involved in various pathological conditions including aging, tissue dysfunction and chronic diseases. Oxidative stress (OS) can drive senescence due to a loss of balance between pro-oxidant stimuli and antioxidant defences. Therefore, the identification and characterization of antioxidant compounds capable of preventing or counteracting the senescent phenotype is of major interest. However, despite the considerable number of studies, a comprehensive overview of the main antioxidant molecules capable of counteracting OS-induced senescence is still lacking. Here, besides a brief description of the molecular mechanisms implicated in OS-mediated aging, we review and discuss the role of enzymes, mitochondria-targeting compounds, vitamins, carotenoids, organosulfur compounds, nitrogen non-protein molecules, minerals, flavonoids, and non-flavonoids as antioxidant compounds with an anti-aging potential, therefore offering insights into innovative lifespan-extending approaches.

Phlorizin alleviates cholinergic memory impairment and regulates gut microbiota in d-galactose induced mice

We explored the effect of phlorizin against cholinergic memory impairment and dysbacteriosis in D-galactose induced ICR mice. The control (CON) group, D-galactose model (DGM) group, and three groups (DG-PL, DG-PM, DG-PH) treated with phlorizin at 0.01%, 0.02%, and 0.04% (w/w) in diets were raised for 12 weeks. Supplementing with phlorizin reversed the loss of organ coefficient and body weight caused by D-galactose. The functional abilities of phlorizin on hippocampal-dependent spatial learning and memory, anti-oxidation, anti-inflammation were also observed. Meanwhile, phlorizin intervention upregulated the gene expression of Nrf2, GSH-PX, SOD1, decreased the gene expression of NF-κB, TLR-4, TNF-α, and IL-1β in the hippocampus, while enhanced the gene expression of JAM-A, Mucin2, Occludin in the caecum. Furthermore, a neurotransmitter of acetylcholine (ACh) was enhanced, while acetylcholinesterase (AChE) activity was inhibited by phlorizin administration. Moreover, phlorizin administration increased short-chain fatty acids (SCFAs) content, and reduced lipopolysaccharides (LPS) levels, which may relate to the rebuilding of gut microbiota homeostasis. Treatment with phlorizin may be an effective intervention for alleviating cognitive decline and gut microbiota dysbiosis.

Human iPSC-Derived Neurons as A Platform for Deciphering the Mechanisms behind Brain Aging

With an increased life expectancy among humans, aging has recently emerged as a major focus in biomedical research. The lack of in vitro aging models-especially for neurological disorders, where access to human brain tissues is limited-has hampered the progress in studies on human brain aging and various age-associated neurodegenerative diseases at the cellular and molecular level. In this review, we provide an overview of age-related changes in the transcriptome, in signaling pathways, and in relation to epigenetic factors that occur in senescent neurons. Moreover, we explore the current cell models used to study neuronal aging in vitro, including immortalized cell lines, primary neuronal culture, neurons directly converted from fibroblasts (Fib-iNs), and iPSC-derived neurons (iPSC-iNs); we also discuss the advantages and limitations of these models. In addition, the key phenotypes associated with cellular senescence that have been observed by these models are compared. Finally, we focus on the potential of combining human iPSC-iNs with genome editing technology in order to further our understanding of brain aging and neurodegenerative diseases, and discuss the future directions and challenges in the field.

Resveratrol, a novel inhibitor of GLUT9, ameliorates liver and kidney injuries in a D-galactose-induced ageing mouse model via the regulation of uric acid metabolism

Accumulating evidence has shown that chronic injection of d-galactose (d-gal) can mimic natural ageing and induce liver and kidney injury. Previous studies showed that d-gal increased uric acid (UA) levels in mice. The increase in UA levels caused inflammation, accelerated oxidative stress, and aggravated liver and kidney injury. Oxidative stress and inflammation play vital roles in the ageing process. Therefore, reducing the levels of UA in ageing mice improved liver and kidney injury. Glucose transporter 9 (GLUT9) is responsible for the reabsorption of UA in the body, and its inhibition helps downregulate UA levels. The present study investigated the UA-lowering activity of the GLUT9 inhibitor resveratrol (RSV) using the patch clamping technique established in our laboratory in vitro. This research is the first study to demonstrate that RSV effectively inhibits UA uptake via GLUT9 (IC50 = 68.77 μM) in vitro. An in vivo study was also performed to investigate the possible protective effect of RSV on d-gal-induced liver and kidney injury. RSV significantly reduced serum UA levels via the downregulation of GLUT9 mRNA and protein expression and promoted the excretion of excess UA through urine. Biochemical analysis showed that RSV significantly downregulated abnormal increases in serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN) and creatinine (CRE) caused by long-term d-gal treatment, which effectively improved pathological damage, increased superoxide dismutase (SOD) activity and decreased the content of malondialdehyde (MDA) in the liver and kidneys. RSV also downregulated the expression of the inflammatory cytokines, interleukin IL-6, IL-1β and tumor necrosis factor (TNF)-α in the liver and kidneys of ageing mice. Our findings provide new insights into the treatment strategies for ageing-induced liver and kidney injury and reveal a new mechanism of RSV-induced reduction in UA levels in ageing individuals.

Phlorizin exerts potent effects against aging induced by D-galactose in mice and PC12 cells

Phlorizin is the main active ingredient of apple peel and has potential utilization value. Some recent studies have suggested that phlorizin may have antioxidant capacity and protect the liver. The injection of a low dose of d-galactose can cause some changes that resemble accelerated aging in mice. This study explored the protective effects of phlorizin on d-galactose-induced mice and PC12 cells. In this study, ICR mice were divided into a normal group (NOR), a d-galactose model group (d-gal) and phlorizin treatment groups (100 mg kg-1, 200 mg kg-1 and 400 mg kg-1). In addition to the NOR group, four other groups were injected with d-galactose (120 mg kg-1) for 12 weeks. The results showed that phlorizin reduced the decline of strength, coordination and spatial memory caused by aging, increased the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), increased total antioxidant capacity (T-AOC), and reduced the content of malondialdehyde (MDA). On the other hand, phlorizin increased the levels of interleukin-2 (IL-2) and acetylcholine (ACh), reduced the release of interleukin-6 (IL-6), aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and decreased the activity of acetylcholinesterase (AChE) in the brain, improved the expression of antioxidant genes related to the nuclear factor E2-related factor 2 (Nrf2) pathway, and reduced the occurrence of morphological lesions in the hippocampus and liver. In addition, phlorizin improved cell viability and reduced the cytotoxicity of d-galactose-induced oxidative stress in PC12 cells. Meanwhile, the protective effect of phlorizin was abolished in Nrf2 gene knockdown PC12 cells. Furthermore, molecular docking showed that phlorizin could bind Keap1 protein, which can interact with Nrf2 protein. Therefore, these results suggest that phlorizin may delay senescence and enhance antioxidant capacity through the Nrf2 pathway.

Human Serum Albumin-Inspired Glycopeptide-Based Multifunctional Inhibitor of Amyloid-β Toxicity

In Alzheimer's disease (AD), insoluble Aβ42 peptide fragments self-aggregate and form oligomers and fibrils in the brain, causing neurotoxicity. Further, the presence of redox-active metal ions such as Cu2+ enhances the aggregation process through chelation with these Aβ42 aggregates as well as generation of Aβ42-mediated reactive oxygen species (ROS). Herein, we have adopted a bioinspired strategy to design and develop a multifunctional glycopeptide hybrid molecule (Glupep), which can serve as a potential AD therapeutic. This molecule consists of a natural metal-chelating tetrapeptide motif of human serum albumin (HSA), a β-sheet breaker peptide, and a sugar moiety for better bioavailability. We performed different biophysical and docking experiments, which revealed that Glupep not only associates with Aβ42 but also prevents its self-aggregation to form toxic oligomers and fibrils. Moreover, Glupep was also shown to sequester out Cu2+ from the Aβ-Cu2+ complex, reducing the ROS formation and toxicity. Besides, this study also revealed that Glupep could protect PC12-derived neurons from Aβ-Cu2+-mediated toxicity by reducing intracellular ROS generation and stabilizing the mitochondrial membrane potential. All these exciting features show Glupep to be a potent inhibitor of Aβ42-mediated multifaceted toxicity and a prospective therapeutic lead for AD.

D-Galactose-induced accelerated aging model: an overview

To facilitate the process of aging healthily and prevent age-related health problems, efforts to properly understand aging mechanisms and develop effective and affordable anti-aging interventions are deemed necessary. Systemic administration of D-galactose has been established to artificially induce senescence in vitro and in vivo as well as for anti-aging therapeutic interventions studies. The aim of this article is to comprehensively discuss the use of D-galactose to generate a model of accelerated aging and its possible underlying mechanisms involved in different tissues/organs.

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

Objective

D-galactose (D-gal) is well-known agent to induce aging process. In the present study, we selected crocin, the main constituent of Crocus sativus L. (saffron), against D-gal-induced cytotoxicity in human neuroblastoma SH-SY5Y cells.

Methods

Pretreated cells with crocin (25–500 μM, 24 h) were exposed to D-gal (25–400 mM, 48 h). The MTT assay was used for determination cell viability. Dichlorofluorescin diacetate assay (DCF-DA) and senescence associated β-galactosidase staining assay (SA-β-gal) were used to evaluate the generation of reactive oxygen species and beta-galactosidase as an aging marker, respectively. Also advanced glycation end products (AGEs) expression which is known as the main mechanism of age-related diseases was measured by western blot analysis.

Results

The findings of our study showed that treatment of cells with D-gal (25–400 mM) for 48h decreased cell viability concentration dependency. Reactive oxygen species (ROS) levels which are known as main factors in age-related diseases increased from 100 ± 8% in control group to 132 ± 22% in D-gal (200 mM) treated cells for 48h. The cytotoxic effects of D-gal decreased with 24h crocin pretreatment of cells. The cell viability at concentrations of 100 μM, 200 μM and 500 μM increased and ROS production decreased at concentrations of 200 and 500 μM to 111.5 ± 6% and 108 ± 5%, respectively. Also lysosomal biomarker of aging and carboxymethyl lysine (CML) expression as an AGE protein, significantly increased in D-gal 200 mM group after 48h incubation compare to control group. Pretreatment of SHSY-5Y cells with crocin (500 μM) before adding D-gal significantly reduced aging marker and CML formation.

Conclusion

Treatment of SH-SY5Y cells with crocin before adding of D-gal restored aging effects of D-gal concentration dependency. These findings indicate that crocin has potent anti-aging effects through inhibition of AGEs and ROS production.

Effects of Portulaca oleracea ethanolic extract on reproductive system of aging female mice

BACKGROUND

Aging contains morphological and functional deterioration in biological systems. D-galactose (D-gal) generates free radicals and accelerates aging. Portulaca oleracea (Purslane) may have protective effect against oxidative stress.

OBJECTIVE

Purslane ethanolic extract effects were evaluated on antioxidant indices and sex hormone in D-gal aging female mice.

MATERIALS AND METHODS

48 female NMRI mice (25-35 gr) were randomly divided into, 6 groups: 1- control (normal saline for 45 days), 2- Purslane (200 mg/kg for last 3 weeks), 3-D-gal (500 mg/kg for 45 days), 4-D-gal+Purslane, 5- Aging, 6-Aging+Purslane. Sex hormones, antioxidants and malondialdehyde (MDA) level of ovary and uterus were measured. Histological assessment was also done.

RESULTS

In D-gal treated and aging animals, LH and FSH levels were significantly increased (p<0.001) while estrogen and progesterone levels were significantly reduced (p<0.001) in comparison with control group. MDA contents were significantly increased in ovaries and uterus of D-gal and aging groups (p<0.01). Superoxide dismutase (SOD) (p<0.001) and catalase (p<0.01) activities were significantly decreased in both aging and D-gal treated animals. Ovarian follicles were degenerated and atrophy on uterine wall and endometrial glands was observed in D-gal and aging groups. Alteration in hormone levels, MDA contents and antioxidant activity were significantly reversed by Purslane (p<0.05). Purslane could also improve histological changes such as atrophy of endometrium.

CONCLUSION

These findings indicate that Purslane can attenuate aging alternations induced by D-gal and aging in female reproductive system.

D-galactose induces a mitochondrial complex I deficiency in mouse skeletal muscle: potential benefits of nutrient combination in ameliorating muscle impairment

Accumulating research has shown that chronic D-galactose (D-gal) exposure induces symptoms similar to natural aging in animals. Therefore, rodents chronically exposed to D-gal are increasingly used as a model for aging and delay-of-aging pharmacological research. Mitochondrial dysfunction is thought to play a vital role in aging and age-related diseases; however, whether mitochondrial dysfunction plays a significant role in mice exposed to D-gal remains unknown. In the present study, we investigated cognitive dysfunction, locomotor activity, and mitochondrial dysfunction involved in D-gal exposure in mice. We found that D-gal exposure (125 mg/kg/day, 8 weeks) resulted in a serious impairment in grip strength in mice, whereas spatial memory and locomotor coordination remained intact. Interestingly, muscular mitochondrial complex I deficiency occurred in the skeletal muscle of mice exposed to D-gal. Mitochondrial ultrastructure abnormality was implicated as a contributing factor in D-gal-induced muscular impairment. Moreover, three combinations (A, B, and C) of nutrients applied in this study effectively reversed D-gal-induced muscular impairment. Nutrient formulas B and C were especially effective in reversing complex I dysfunction in both skeletal muscle and heart muscle. These findings suggest the following: (1) chronic exposure to D-gal first results in specific muscular impairment in mice, rather than causing general, premature aging; (2) poor skeletal muscle strength induced by D-gal might be due to the mitochondrial dysfunction caused by complex I deficiency; and (3) the nutrient complexes applied in the study attenuated the skeletal muscle impairment, most likely by improving mitochondrial function.