Caloric restriction and the precision-control of autophagy: A strategy for delaying neurodegenerative disease progression

Treatment with walnut peptide ameliorates memory impairment in zebrafish and rats: promoting the expression of neurotrophic factors and suppressing oxidative stress

Walnut peptide, a low molecular weight peptide separated from walnuts by enzymatic hydrolysis, is considered as a potential nutraceutical with a variety of biological activities. In this study, we characterized the walnut peptide prepared by alkaline protease hydrolysis and evaluated its neuroprotective effect in zebrafish and rat models of memory disorders. Series of concentrations of the walnut peptide were orally administered to zebrafish and rats to examine its impact on the behavior and biochemical indicators. The results showed that the oral administration of walnut peptide significantly ameliorated the behavioral performance in zebrafish exposed to bisphenol AF (1 μg mL-1) and rats exposed to alcohol (30% ethanol, 10 mL kg-1). Furthermore, the walnut peptide upregulated the expression of neurotrophic-related molecules in zebrafish, such as the brain-derived neurotrophic factor (BDNF) and the glial cell-derived neurotrophic factor (GDNF). In the rat brain, the walnut peptide increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), while dramatically reduced malondialdehyde (MDA) level. Together, these findings elucidated that the walnut peptide might partially offset the declarative memory deficits via regulation of neurotrophic-related molecule expression and promotion of the antioxidant defense ability. Therefore, walnut peptide holds the potential for development into functional foods as a nutritional supplement for the management of certain neurodegenerative disorders.

Caloric restriction leading to attenuation of experimental Alzheimer's disease results from alterations in gut microbiome

BACKGROUND

Caloric restriction (CR) might be effective for alleviating/preventing Alzheimer's disease (AD), but the biological mechanisms remain unclear. In the current study, we explored whether CR caused an alteration of gut microbiome and resulted in the attenuation of cognitive impairment of AD animal model.

METHODS

Thirty-week-old male APP/PS1 transgenic mice were used as AD models (AD mouse). CR was achieved by 30% reduction of daily free feeding (ad libitum, AL) amount. The mice were fed with CR protocol or AL protocol for six consecutive weeks.

RESULTS

We found that with CR treatment, AD mice showed improved ability of learning and spatial memory, and lower levels of Aβ40, Aβ42, IL-1β, TNF-α, and ROS in the brain. By sequencing 16S rDNA, we found that CR treatment resulted in significant diversity in composition and abundance of gut flora. At the phylum level, Deferribacteres (0.04%), Patescibacteria (0.14%), Tenericutes (0.03%), and Verrucomicrobia (0.5%) were significantly decreased in CR-treated AD mice; at the genus level, Dubosiella (10.04%), Faecalibaculum (0.04%), and Coriobacteriaceae UCG-002 (0.01%) were significantly increased in CR-treated AD mice by comparing with AL diet.

CONCLUSIONS

Our results demonstrate that the attenuation of AD following CR treatment in APP/PS1 mice may result from alterations in the gut microbiome. Thus, gut flora could be a new target for AD prevention and therapy.

Mechanistic insights into fasting-induced autophagy in the aging heart

Autophagy is a prosurvival mechanism for the clearance of accumulated abnormal proteins, damaged organelles, and excessive lipids within mammalian cells. A growing body of data indicates that autophagy is reduced in aging cells. This reduction leads to various diseases, such as myocardial hypertrophy, infarction, and atherosclerosis. Recent studies in animal models of an aging heart showed that fasting-induced autophagy improved cardiac function and longevity. This improvement is related to autophagic clearance of damaged cellular components via either bulk or selective autophagy (such as mitophagy). In this editorial, we summarize the mechanisms of autophagy in normal and aging hearts. In addition, the protective effect of fasting-induced autophagy in cardiac aging has been highlighted.

Calorie restriction modulates the transcription of genes related to stress response and longevity in human muscle: The CALERIE study

The lifespan extension induced by 40% caloric restriction (CR) in rodents is accompanied by postponement of disease, preservation of function, and increased stress resistance. Whether CR elicits the same physiological and molecular responses in humans remains mostly unexplored. In the CALERIE study, 12% CR for 2 years in healthy humans induced minor losses of muscle mass (leg lean mass) without changes of muscle strength, but mechanisms for muscle quality preservation remained unclear. We performed high-depth RNA-Seq (387-618 million paired reads) on human vastus lateralis muscle biopsies collected from the CALERIE participants at baseline, 12- and 24-month follow-up from the 90 CALERIE participants randomized to CR and "ad libitum" control. Using linear mixed effect model, we identified protein-coding genes and splicing variants whose expression was significantly changed in the CR group compared to controls, including genes related to proteostasis, circadian rhythm regulation, DNA repair, mitochondrial biogenesis, mRNA processing/splicing, FOXO3 metabolism, apoptosis, and inflammation. Changes in some of these biological pathways mediated part of the positive effect of CR on muscle quality. Differentially expressed splicing variants were associated with change in pathways shown to be affected by CR in model organisms. Two years of sustained CR in humans positively affected skeletal muscle quality, and impacted gene expression and splicing profiles of biological pathways affected by CR in model organisms, suggesting that attainable levels of CR in a lifestyle intervention can benefit muscle health in humans.

Astragaloside IV ameliorates radiation-induced nerve cell damage by activating the BDNF/TrkB signaling pathway

Radiation can induce nerve cell damage. Synapse connectivity and functionality are thought to be the essential foundation of all cognitive functions. Therefore, treating and preventing damage to synaptic structure and function is an urgent challenge. Astragaloside IV (AS-IV) is a glycoside extracted from Astragalus membranaceus (Fisch.). Bunge is a widely used traditional Chinese medicine in China with various pharmacological properties, including protective effects on the central nervous system (CNS). In this study, the effect of AS-IV on synapse damage and BDNF/TrkB signaling pathway in radiated C57BL/6 mice with X-rays was investigated. PC12 cells and primary cortical neurons were exposed to UVA in vitro. Open field test and rotarod test were used to observe the effects of AS-IV on the motor and explore the abilities of radiated mice. The pathological changes in the brain were observed by hematoxylin and eosin and Nissl staining. Immunofluorescence analysis was used to detect the synapse damage. The expressions of the BDNF/TrkB pathway and neuroprotection-related molecules were detected by Western blotting and Quantitative-RTPCR, respectively. The results showed that AS-IV could improve the motor and explore abilities of radiated mice, reduce pathological damage to the cortex, enhance neuroprotection functions, and activate BDNF/TrkB pathway. In conclusion, AS-IV could relieve radiation-induced synapse damage, at least partly through the BDNF/TrkB pathway.

Neurotrophic effects of intermittent fasting, calorie restriction and exercise: a review and annotated bibliography

In the last decades, important progress has been achieved in the understanding of the neurotrophic effects of intermittent fasting (IF), calorie restriction (CR) and exercise. Improved neuroprotection, synaptic plasticity and adult neurogenesis (NSPAN) are essential examples of these neurotrophic effects. The importance in this respect of the metabolic switch from glucose to ketone bodies as cellular fuel has been highlighted. More recently, calorie restriction mimetics (CRMs; resveratrol and other polyphenols in particular) have been investigated thoroughly in relation to NSPAN. In the narrative review sections of this manuscript, recent findings on these essential functions are synthesized and the most important molecules involved are presented. The most researched signaling pathways (PI3K, Akt, mTOR, AMPK, GSK3β, ULK, MAPK, PGC-1α, NF-κB, sirtuins, Notch, Sonic hedgehog and Wnt) and processes (e.g., anti-inflammation, autophagy, apoptosis) that support or thwart neuroprotection, synaptic plasticity and neurogenesis are then briefly presented. This provides an accessible entry point to the literature. In the annotated bibliography section of this contribution, brief summaries are provided of about 30 literature reviews relating to the neurotrophic effects of interest in relation to IF, CR, CRMs and exercise. Most of the selected reviews address these essential functions from the perspective of healthier aging (sometimes discussing epigenetic factors) and the reduction of the risk for neurodegenerative diseases (Alzheimer's disease, Huntington's disease, Parkinson's disease) and depression or the improvement of cognitive function.

The promise of neuroprotection by dietary restriction in glaucoma

Glaucoma, a progressive age-related optic neuropathy characterized by the death of retinal ganglion cells, is the most common neurodegenerative cause of irreversible blindness worldwide. The therapeutic management of glaucoma, which is limited to lowering intraocular pressure, is still a challenge since visual loss progresses in a significant percentage of treated patients. Restricted dietary regimens have received considerable attention as adjuvant strategy for attenuating or delaying the progression of neurodegenerative diseases. Here we discuss the literature exploring the effects of modified eating patterns on retinal aging and resistance to stressor stimuli.

Mutant Ataxin-3-Containing Aggregates (MATAGGs) in Spinocerebellar Ataxia Type 3: Dynamics of the Disorder

Spinocerebellar ataxia type 3 (SCA3) is the most common type of SCA worldwide caused by abnormal polyglutamine expansion in the coding region of the ataxin-3 gene. Ataxin-3 is a multi-faceted protein involved in various cellular processes such as deubiquitination, cytoskeletal organisation, and transcriptional regulation. The presence of an expanded poly(Q) stretch leads to altered processing and misfolding of the protein culminating in the production of insoluble protein aggregates in the cell. Various post-translational modifications affect ataxin-3 fibrillation and aggregation. This review provides an exhaustive assessment of the various pathogenic mechanisms undertaken by the mutant ataxin-3-containing aggregates (MATAGGs) for disease induction and neurodegeneration. This includes in-depth discussion on MATAGG dynamics including their formation, role in neuronal pathogenesis, and the debate over the toxic v/s protective nature of the MATAGGs in disease progression. Additionally, the currently available therapeutic strategies against SCA3 have been reviewed. The shift in the focus of such strategies, from targeting the steps that lead to or reduce aggregate formation to targeting the expression of mutant ataxin-3 itself via RNA-based therapeutics, has also been presented. We also discuss the intriguing promise that various growth and neurotrophic factors, especially the insulin pathway, hold in the modulation of SCA3 progression. These emerging areas show the newer directions through which SCA3 can be targeted including various preclinical and clinical trials. All these advances made in the last three decades since the discovery of the ataxin-3 gene have been critically reviewed here.

Stimulation of AMPK Prevents Diabetes-Induced Photoreceptor Cell Degeneration

Diabetic retinopathy (DR) is a kind of severe retinal neurodegeneration. The advanced glycation end products (AGEs) affect autophagy, and mitochondrial function is involved in DR. Adenosine-activated protein kinase (AMPK) is an important metabolic sensor that can regulate energy homeostasis in cells. However, the effect of AMPK in DR is still not fully understood. In this study, we investigated the effect of AMPK on diabetes-induced photoreceptor cell degeneration. In vivo, a diabetic mouse model was established by streptozotocin (STZ) injection. Haematoxylin-eosin (HE) staining was used to observe retinal morphology and measure the thicknesses of different layers in the retina. Electroretinogram (ERG) was used to evaluate retinal function. In vitro, 661w cells were treated with AGEs with/without an AMPK agonist (metformin) or AMPK inhibitor (compound C). Flow cytometry and CCK-8 assays were used to analyse apoptosis. Mitochondrial membrane potential was analysed by JC-1. Western blotting and qRT-PCR were used to examine the expression of related proteins and genes, respectively. The wave amplitude and the thickness of the outer nuclear layer were decreased in diabetic mice. The expression of rhodopsin and opsin was also decreased in diabetic mice. In vitro, the percentage of apoptotic cells was increased, the expression of the apoptosis-related protein Bax was increased, and Bcl-2 was decreased after AGE treatment in 661w cells. The expression of the autophagy-related protein LC3 was decreased, and p62 was increased. The mitochondrial-related gene expression and membrane potential were decreased, and mitochondrial morphology was abnormal, as observed by TEM. However, AMPK stimulation ameliorated this effect. These results indicate that AMPK stimulation can delay diabetes-induced photoreceptor degeneration by regulating autophagy and mitochondrial function.

How the brain fights fatty acids' toxicity

Neurons spurn hydrogen-rich fatty acids for energizing oxidative ATP synthesis, contrary to other cells. This feature has been mainly attributed to a lower yield of ATP per reduced oxygen, as compared to glucose. Moreover, the use of fatty acids as hydrogen donor is accompanied by severe β-oxidation-associated ROS generation. Neurons are especially susceptible to detrimental activities of ROS due to their poor antioxidative equipment. It is also important to note that free fatty acids (FFA) initiate multiple harmful activities inside the cells, particularly on phosphorylating mitochondria. Several processes enhance FFA-linked lipotoxicity in the cerebral tissue. Thus, an uptake of FFA from the circulation into the brain tissue takes place during an imbalance between energy intake and energy expenditure in the body, a situation similar to that during metabolic syndrome and fat-rich diet. Traumatic or hypoxic brain injuries increase hydrolytic degradation of membrane phospholipids and, thereby elevate the level of FFA in neural cells. Accumulation of FFA in brain tissue is markedly associated with some inherited neurological disorders, such as Refsum disease or X-linked adrenoleukodystrophy (X-ALD). What are strategies protecting neurons against FFA-linked lipotoxicity? Firstly, spurning the β-oxidation pathway in mitochondria of neurons. Secondly, based on a tight metabolic communication between neurons and astrocytes, astrocytes donate metabolites to neurons for synthesis of antioxidants. Further, neuronal autophagy of ROS-emitting mitochondria combined with the transfer of degradation-committed FFA for their disposal in astrocytes, is a potent protective strategy against ROS and harmful activities of FFA. Finally, estrogens and neurosteroids are protective as triggers of ERK and PKB signaling pathways, consequently initiating the expression of various neuronal survival genes via the formation of cAMP response element-binding protein (CREB).

Inhibiting mTOR activity using AZD2014 increases autophagy in the mouse cerebral cortex

Autophagy is a catabolic process that collects and degrades damaged or unwanted cellular materials such as protein aggregates. Defective brain autophagy has been linked to diseases such as Alzheimer's disease. Autophagy is regulated by the protein kinase mTOR (mechanistic target of rapamycin). Although already demonstrated in vitro, it remains contentious whether inhibiting mTOR can enhance autophagy in the brain. To address this, mice were intraperitoneally injected with the mTOR inhibitor AZD2014 for seven days. mTOR complex 1 (mTORC1) activity was decreased in liver and brain. Autophagic activity was increased by AZD2014 in both organs, as measured by immunoblotting for LC3 (microtubule-associated proteins-1A/1B light chain 3B) and measurement of autophagic flux in the cerebral cortex of transgenic mice expressing the EGFP-mRFP-LC3B transgene. mTOR activity was shown to correlate with changes in LC3. Thus, we show it is possible to promote autophagy in the brain using AZD2014, which will be valuable in tackling conditions associated with defective autophagy, especially neurodegeneration.

Neuregulins in Neurodegenerative Diseases

Neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS), are typically characterized by progressive neuronal loss and neurological dysfunctions in the nervous system, affecting both memory and motor functions. Neuregulins (NRGs) belong to the epidermal growth factor (EGF)-like family of extracellular ligands and they play an important role in the development, maintenance, and repair of both the central nervous system (CNS) and peripheral nervous system (PNS) through the ErbB signaling pathway. They also regulate multiple intercellular signal transduction and participate in a wide range of biological processes, such as differentiation, migration, and myelination. In this review article, we summarized research on the changes and roles of NRGs in neurodegenerative diseases, especially in AD. We elaborated on the structural features of each NRG subtype and roles of NRG/ErbB signaling networks in neurodegenerative diseases. We also discussed the therapeutic potential of NRGs in the symptom remission of neurodegenerative diseases, which may offer hope for advancing related treatment.

Transcriptional block of AMPK-induced autophagy promotes glutamate excitotoxicity in nutrient-deprived SH-SY5Y neuroblastoma cells

We investigated the role of autophagy, a controlled lysosomal degradation of cellular macromolecules and organelles, in glutamate excitotoxicity during nutrient deprivation in vitro. The incubation in low-glucose serum/amino acid-free cell culture medium synergized with glutamate in increasing AMP/ATP ratio and causing excitotoxic necrosis in SH-SY5Y human neuroblastoma cells. Glutamate suppressed starvation-triggered autophagy, as confirmed by diminished intracellular acidification, lower LC3 punctuation and LC3-I conversion to autophagosome-associated LC3-II, reduced expression of proautophagic beclin-1 and ATG5, increase of the selective autophagic target NBR1, and decreased number of autophagic vesicles. Similar results were observed in PC12 rat pheochromocytoma cells. Both glutamate-mediated excitotoxicity and autophagy inhibition in starved SH-SY5Y cells were reverted by NMDA antagonist memantine and mimicked by NMDA agonists D-aspartate and ibotenate. Glutamate reduced starvation-triggered phosphorylation of the energy sensor AMP-activated protein kinase (AMPK) without affecting the activity of mammalian target of rapamycin complex 1, a major negative regulator of autophagy. This was associated with reduced mRNA levels of autophagy transcriptional activators (FOXO3, ATF4) and molecules involved in autophagy initiation (ULK1, ATG13, FIP200), autophagosome nucleation/elongation (ATG14, beclin-1, ATG5), and autophagic cargo delivery to autophagosomes (SQSTM1). Glutamate-mediated transcriptional repression of autophagy was alleviated by overexpression of constitutively active AMPK. Genetic or pharmacological AMPK activation by AMPK overexpression or metformin, as well as genetic or pharmacological autophagy induction by TFEB overexpression or lithium chloride, reduced the sensitivity of nutrient-deprived SH-SY5Y cells to glutamate excitotoxicity. These data indicate that transcriptional inhibition of AMPK-dependent cytoprotective autophagy is involved in glutamate-mediated excitotoxicity during nutrient deprivation in vitro.

Effects of caloric restriction on retinal aging and neurodegeneration

Glaucoma is the most common neurodegenerative cause of irreversible blindness worldwide. Restricted caloric regimens are an attractive approach for delaying the progression of neurodegenerative diseases. Here we review the current literature on the effects of caloric restriction on retinal neurons, under physiological and pathological conditions. We focused on autophagy as one of the mechanisms modulated by restricted caloric regimens and involved in the death of retinal ganglion cells (RGCs) over the course of glaucoma.

Sustained mitochondrial biogenesis is essential to maintain caloric restriction-induced beige adipocytes

BACKGROUND

Caloric restriction (CR) delays the onset of metabolic and age-related disorders. Recent studies have demonstrated that formation of beige adipocytes induced by CR is strongly associated with extracellular remodeling in adipose tissue, decrease in adipose tissue inflammation, and improved systemic metabolic homeostasis. However, beige adipocytes rapidly transition to white upon CR withdrawal through unclear mechanisms.

MATERIALS AND METHODS

Six-week old C57BL6 mice were fed with 40% CR chow diet for 6 weeks. Subsequently, one group of mice was switched back to ad libitum chow diet, which was continued for additional 2 weeks. Adipose tissues were assessed histologically and biochemically for beige adipocytes.

RESULTS

Beige adipocytes induced by CR rapidly transition to white adipocytes when CR is withdrawn independent of parkin-mediated mitophagy. We demonstrate that the involution of mitochondria during CR withdrawal is strongly linked with a decrease in mitochondrial biogenesis. We further demonstrate that beige-to-white fat transition upon β3-AR agonist-withdrawal could be attenuated by CR, partly via maintenance of mitochondrial biogenesis.

CONCLUSION

In the model of CR, our study highlights the dominant role of mitochondrial biogenesis in the maintenance of beige adipocytes. We propose that loss of beige adipocytes upon β3-AR agonist withdrawal could be attenuated by CR.

Efficacy of a Short-Term Low-Calorie Diet in Overweight and Obese Patients with Chronic Sciatica: A Randomized Controlled Trial

Objectives: Chronic sciatica is a common condition. According to Traditional Persian Medicine and recent studies, calorie reduction is thought to be helpful for this condition. The purpose of this work is to evaluate a short-term low-calorie diet (LCD) for ameliorating chronic sciatica in the context of pain relief and reduced disability for patients. Design: In this randomized controlled trial, 96 candidates for the nonsurgical treatment of chronic sciatica were randomly assigned to two groups to receive a 1-month LCD (intervention) or ordinary diet (control), both in combination with nonsteroidal anti-inflammatory drugs (NSAIDs). Afterward, patients were visited at baseline and on days 15, 30, and 60 after treatment. Pain and disability were evaluated using the short-form McGill pain questionnaire (SFMPQ) and the Roland-Morris disability questionnaire (RMDQ), respectively. Results: Both mean RMDQ scores and SFMPQ scores decreased significantly in the LCD group compared to the control group. SFMPQ descriptor scale scores at baseline and on days 15, 30, and 60 in the LCD group were 7.71 ± 1.69, 6.63 ± 1.61, 5.54 ± 1.87, and 4.96 ± 2.02, respectively, and in the control group were 6.63 ± 1.44, 6.69 ± 1.32, 6.64 ± 1.98, and 6.62 ± 2.53, respectively (p = 0.001). RMDQ scores at baseline and on days 15, 30, and 60 in LCD group were 11.17 ± 3.90, 8.60 ± 1.97, 7.50 ± 2.71, and 6.77 ± 3.06, respectively, and in the control group, 10.00 ± 2.20, 9.98 ± 2.29, 9.94 ± 2.94, and 9.85 ± 3.32, respectively (p < 0.001). Conclusion: A short-term (1-month) LCD is effective in decreasing pain and disability in candidates for nonsurgical treatment of chronic sciatica.

12 days of in vivo caloric reduction can improve important parameters of aging in humans

Caloric reduction (CR) is considered as the most reasonable intervention to delay aging and age-related diseases. Numerous studies in various model organisms provide the main basis for this hypothesis. Human studies exist, but they differ widely in study design, characteristics of test persons and study outcome. In this study we investigated CR in humans on a molecular level to gain a better understanding in these processes. For that purpose, we analyzed human peripheral blood mononuclear cells of healthy people fasting according to F.X. Mayr. In a previous study our group could show a significantly improved DNA repair capacity after fasting. Here we were able to confirm these findings despite a slightly modified fasting therapy. Furthermore, the function of the mitochondrial respiratory chain and the mRNA levels of the mitochondria-associated genes SIRT3 and NDUFS1 were significantly affected by CR. However, these changes were only detectable in people who exhibited no improvement in DNA repair capacity. In contrast to that we could not observe any changes in ROS levels, mitochondrial DNA copy number and non-mitochondrial respiration. Altogether our results reveal that CR in form of F. X. Mayr therapy is able to positively influence several cellular parameters and especially mitochondrial function.

A Systematic Bioinformatics Workflow With Meta-Analytics Identified Potential Pathogenic Factors of Alzheimer's Disease

Potential pathogenic factors, other than well-known APP, APOE4, and PSEN, can be further identified from transcriptomics studies of differentially expressed genes (DEGs) that are specific for Alzheimer’s disease (AD), but findings are often inconsistent or even contradictory. Evidence corroboration by combining meta-analysis and bioinformatics methods may help to resolve existing inconsistencies and contradictions. This study aimed to demonstrate a systematic workflow for evidence synthesis of transcriptomic studies using both meta-analysis and bioinformatics methods to identify potential pathogenic factors. Transcriptomic data were assessed from GEO and ArrayExpress after systematic searches. The DEGs and their dysregulation states from both DNA microarray and RNA sequencing datasets were analyzed and corroborated by meta-analysis. Statistically significant DEGs were used for enrichment analysis based on KEGG and protein–protein interaction network (PPIN) analysis based on STRING. AD-specific modules were further determined by the DIAMOnD algorithm, which identifies significant connectivity patterns between specific disease-associated proteins and non-specific proteins. Within AD-specific modules, the nodes of highest degrees (>95th percentile) were considered as potential pathogenic factors. After systematic searches of 225 datasets, extensive meta-analyses among 25 datasets (21 DNA microarray datasets and 4 RNA sequencing datasets) identified 9,298 DEGs. The dysregulated genes and pathways in AD were associated with impaired amyloid-β (Aβ) clearance. From the AD-specific module, Fyn, and EGFR were the most statistically significant and biologically relevant. This meta-analytical study suggested that the reduced Aβ clearance in AD pathogenesis was associated with the genes encoding Fyn and EGFR, which were key receptors in Aβ downstream signaling.

Precision Medicine in Lifestyle Medicine: The Way of the Future?

Precision medicine has captured the imagination of the medical community with visions of therapies precisely targeted to the specific individual's genetic, biological, social, and environmental profile. However, in practice it has become synonymous with genomic medicine. As such its successes have been limited, with poor predictive or clinical value for the majority of people. It adds little to lifestyle medicine, other than in establishing why a healthy lifestyle is effective in combatting chronic disease. The challenge of lifestyle medicine remains getting people to actually adopt, sustain, and naturalize a healthy lifestyle, and this will require an approach that treats the patient as a person with individual needs and providing them with suitable types of support. The future of lifestyle medicine is holistic and person-centered rather than technological.

Molecular Mechanism of Autophagy: Its Role in the Therapy of Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder of progressive dementia that is characterized by the accumulation of beta-amyloid (Aβ)-containing neuritic plaques and intracellular Tau protein tangles. This distinctive pathology indicates that the protein quality control is compromised in AD. Autophagy functions as a "neuronal housekeeper" that eliminates aberrant protein aggregates by wrapping then into autophagosomes and delivering them to lysosomes for degradation. Several studies have suggested that autophagy deficits in autophagy participate in the accumulation and propagation of misfolded proteins (including Aβ and Tau). In this review, we summarize current knowledge of autophagy in the pathogenesis of AD, as well as some pathways targeting the restoration of autophagy. Moreover, we discuss how these aspects can contribute to the development of disease-modifying therapies in AD.

Impact of caloric restriction on peripheral nerve injury-induced neuropathic pain during ageing in mice

The incidence of peripheral neuropathy development and chronic pain is strongly associated with the arrival of senescence. The gradual physiological decline that begins after the mature stage produces myelin dysregulation and pathological changes in peripheral nervous system, attributed to reduction in myelin proteins expression and thinner myelin sheath. Moreover in elder subjects, when nerve damage occurs, the regenerative processes are seriously compromised and neuropathic pain (NeP) is maintained. We previously demonstrated that caloric restriction (CR) in adult (4 months) nerve-lesioned mice was able to facilitate remyelination and axons regeneration, to have anti-inflammatory action and to prevent NeP chronification. Here, we show CR therapeutic potential on nerve injury-induced neuropathy in mice at the beginning of the senescence (12 months). Long lasting decrease in hypersensitvity induced by peripheral nerve lesion and powerful reduction in proinflammatory circulating agents have been observed. Moreover, our results evidence that CR is able to counteract the ageing-related delay in axonal regeneration, enhancing Schwann cells proliferation and accelerating recovery processes. Differently from adults, it does not affect fibres myelination. In light of a continuous growth in elderly population and correlated health problems, including metabolic disorders, the prevalence of neuropathy is enhancing, generating a significant public cost and social concern. In this context energy depletion by dietary restriction can be a therapeutic option in NeP.

Postsynaptic Proteome of Non-Demented Individuals with Alzheimer's Disease Neuropathology

Some individuals, here referred to as Non-Demented with Alzheimer’s Neuropathology (NDAN), retain their cognitive function despite the presence of amyloid plaques and tau tangles typical of symptomatic Alzheimer’s disease (AD). In NDAN, unlike AD, toxic amyloid-β oligomers do not localize to the postsynaptic densities (PSDs). Synaptic resistance to amyloid-β in NDAN may thus enable these individuals to remain cognitively intact despite the AD-like pathology. The mechanism(s) responsible for this resistance remains unresolved and understanding such protective biological processes could reveal novel targets for the development of effective treatments for AD. The present study uses a proteomic approach to compare the hippocampal postsynaptic densities of NDAN, AD, and healthy age-matched persons to identify protein signatures characteristic for these groups. Subcellular fractionation followed by 2D gel electrophoresis and mass spectrometry were used to analyze the PSDs. We describe fifteen proteins which comprise the unique proteomic signature of NDAN PSDs, thus setting them apart from control subjects and AD patients.

Insulin and Autophagy in Neurodegeneration

Crosstalk in the pathophysiological processes underpinning metabolic diseases and neurodegenerative disorders have been the subject of extensive investigation, in which insulin signaling and autophagy impairment demonstrate to be a common factor in both conditions. Although it is still somewhat conflicting, pharmacological and genetic strategies that regulate these pathways may be a promising approach for aggregate protein clearancing and consequently the delaying of onset or progression of the disease. However, as the response due to this modulation seems to be time-dependent, finding the right regulation of autophagy may be a potential target for drug development for neurodegenerative diseases. In this way, this review focuses on the role of insulin signaling/resistance and autophagy in some neurodegenerative diseases, discussing pharmacological and non-pharmacological interventions in these diseases.

Genetics, Mechanisms, and Therapeutic Progress in Polyglutamine Spinocerebellar Ataxias

Autosomal dominant cerebellar ataxias (ADCAs) are a group of neurodegenerative disorders characterized by degeneration of the cerebellum and its connections. All ADCAs have progressive ataxia as their main clinical feature, frequently accompanied by dysarthria and oculomotor deficits. The most common spinocerebellar ataxias (SCAs) are 6 polyglutamine (polyQ) SCAs. These diseases are all caused by a CAG repeat expansion in the coding region of a gene. Currently, no curative treatment is available for any of the polyQ SCAs, but increasing knowledge on the genetics and the pathological mechanisms of these polyQ SCAs has provided promising therapeutic targets to potentially slow disease progression. Potential treatments can be divided into pharmacological and gene therapies that target the toxic downstream effects, gene therapies that target the polyQ SCA genes, and stem cell replacement therapies. Here, we will provide a review on the genetics, mechanisms, and therapeutic progress in polyglutamine spinocerebellar ataxias.

Maternal perinatal calorie restriction temporally regulates the hepatic autophagy and redox status in male rat

Intrauterine growth restriction (IUGR) leads to adult obesity, cardiovascular disease, and non-alcoholic fatty liver disease/steatohepatitis. Animal models have shown that combined intrauterine and early postnatal calorie restriction (IPCR) ameliorates these sequelae in adult life. The mechanism by which IPCR protects against adult onset disease is not understood. Autophagy, a lysosomal degradative process, recycles cellular constituents and eliminates damaged organelles, proteins, and oxidants. In this study, we hypothesized that IPCR could regulate autophagy in the liver of male rat offspring. At birth (d1) of male IUGR rat offspring and on day 21 (p21) of life, IPCR male rat offspring had a profound decrease in hepatic autophagy in all three stages of development: initiation, elongation, and maturation. However, upon receiving a normal diet ad-lib throughout adulthood, aged IPCR rats (day 450 of life (p450)), had increased hepatic autophagy, in direct contrast to what was seen in early life. The decreased autophagy at d21 led to the accumulation of ubiquitinated proteins and lipid oxidative products, whereas the increased autophagy in late life had the opposite effect. Oxidized lipids were unchanged at d1 by IUGR treatment indicating that decreased autophagy precedes oxidative stress in early life. When cellular signaling pathways regulating autophagy were examined, the 5' adenosine monophosphate-activated protein kinase pathway (AMPK), and not endoplasmic stress pathways, was found to be altered, suggesting that autophagy is regulated through AMPK signaling pathway in IPCR rats. Taken together, this study reveals that the perinatal nutritional status establishes a nutritionally sensitive memory that enhances hepatic autophagy in late life, a process that perhaps acts as a protective mechanism to limited nutrition.

The effect of fasting or calorie restriction on autophagy induction: A review of the literature

Autophagy is a lysosomal degradation process and protective housekeeping mechanism to eliminate damaged organelles, long-lived misfolded proteins and invading pathogens. Autophagy functions to recycle building blocks and energy for cellular renovation and homeostasis, allowing cells to adapt to stress. Modulation of autophagy is a potential therapeutic target for a diverse range of diseases, including metabolic conditions, neurodegenerative diseases, cancers and infectious diseases. Traditionally, food deprivation and calorie restriction (CR) have been considered to slow aging and increase longevity. Since autophagy inhibition attenuates the anti-aging effects of CR, it has been proposed that autophagy plays a substantive role in CR-mediated longevity. Among several stress stimuli inducers of autophagy, fasting and CR are the most potent non-genetic autophagy stimulators, and lack the undesirable side effects associated with alternative interventions. Despite the importance of autophagy, the evidence connecting fasting or CR with autophagy promotion has not previously been reviewed. Therefore, our objective was to weigh the evidence relating the effect of CR or fasting on autophagy promotion. We conclude that both fasting and CR have a role in the upregulation of autophagy, the evidence overwhelmingly suggesting that autophagy is induced in a wide variety of tissues and organs in response to food deprivation.

Glucosamine Extends the Lifespan of Caenorhabditis elegans via Autophagy Induction

Glucosamine (GlcN) is commonly used as a dietary supplement to promote cartilage health in humans. We previously reported that GlcN could induce autophagy in cultured mammalian cells. Autophagy is known to be involved in the prevention of various diseases and aging. Here, we showed that GlcN extended the lifespan of the nematode Caenorhabditis elegans by inducing autophagy. Autophagy induction by GlcN was demonstrated by western blotting for LGG-1 (an ortholog of mammalian LC3) and by detecting autophagosomal dots in seam cells by fluorescence microscopy. Lifespan assays revealed that GlcN-induced lifespan extension was achieved with at least 5 mM GlcN. A maximum lifespan extension of approximately 30 % was achieved with 20 mM GlcN (p<0.0001). GlcN-induced lifespan extension was not dependent on the longevity genes daf-16 and sir-2.1 but dependent on the autophagy-essential gene atg-18. Therefore, we suggest that oral administration of GlcN could help delay the aging process via autophagy induction.

The Precision Control of Autophagic Flux and Vesicle Dynamics-A Micropattern Approach

Autophagy failure is implicated in age-related human disease. A decrease in the rate of protein degradation through the entire autophagy pathway, i.e., autophagic flux, has been associated with the onset of cellular proteotoxity and cell death. Although the precision control of autophagy as a pharmacological intervention has received major attention, mammalian model systems that enable a dissection of the relationship between autophagic flux and pathway intermediate pool sizes remain largely underexplored. Here, we make use of a micropattern-based fluorescence life cell imaging approach, allowing a high degree of experimental control and cellular geometry constraints. By assessing two autophagy modulators in a system that achieves a similarly raised autophagic flux, we measure their impact on the pathway intermediate pool size, autophagosome velocity, and motion. Our results reveal a differential effect of autophagic flux enhancement on pathway intermediate pool sizes, velocities, and directionality of autophagosome motion, suggesting distinct control over autophagy function. These findings may be of importance for better understanding the fine-tuning autophagic activity and protein degradation proficiency in different cell and tissue types of age-associated pathologies.

Preventing mutant huntingtin proteolysis and intermittent fasting promote autophagy in models of Huntington disease

Huntington disease (HD) is caused by the expression of mutant huntingtin (mHTT) bearing a polyglutamine expansion. In HD, mHTT accumulation is accompanied by a dysfunction in basal autophagy, which manifests as specific defects in cargo loading during selective autophagy. Here we show that the expression of mHTT resistant to proteolysis at the caspase cleavage site D586 (C6R mHTT) increases autophagy, which may be due to its increased binding to the autophagy adapter p62. This is accompanied by faster degradation of C6R mHTT in vitro and a lack of mHTT accumulation the C6R mouse model with age. These findings may explain the previously observed neuroprotective properties of C6R mHTT. As the C6R mutation cannot be easily translated into a therapeutic approach, we show that a scheduled feeding paradigm is sufficient to lower mHTT levels in YAC128 mice expressing cleavable mHTT. This is consistent with a previous model, where the presence of cleavable mHTT impairs basal autophagy, while fasting-induced autophagy remains functional. In HD, mHTT clearance and autophagy may become increasingly impaired as a function of age and disease stage, because of gradually increased activity of mHTT-processing enzymes. Our findings imply that mHTT clearance could be enhanced by a regulated dietary schedule that promotes autophagy.

Oxidative Stress, Synaptic Dysfunction, and Alzheimer's Disease

Alzheimer's disease (AD) is a devastating neurodegenerative disorder without a cure. Most AD cases are sporadic where age represents the greatest risk factor. Lack of understanding of the disease mechanism hinders the development of efficacious therapeutic approaches. The loss of synapses in the affected brain regions correlates best with cognitive impairment in AD patients and has been considered as the early mechanism that precedes neuronal loss. Oxidative stress has been recognized as a contributing factor in aging and in the progression of multiple neurodegenerative diseases including AD. Increased production of reactive oxygen species (ROS) associated with age- and disease-dependent loss of mitochondrial function, altered metal homeostasis, and reduced antioxidant defense directly affect synaptic activity and neurotransmission in neurons leading to cognitive dysfunction. In addition, molecular targets affected by ROS include nuclear and mitochondrial DNA, lipids, proteins, calcium homeostasis, mitochondrial dynamics and function, cellular architecture, receptor trafficking and endocytosis, and energy homeostasis. Abnormal cellular metabolism in turn could affect the production and accumulation of amyloid-β (Aβ) and hyperphosphorylated Tau protein, which independently could exacerbate mitochondrial dysfunction and ROS production, thereby contributing to a vicious cycle. While mounting evidence implicates ROS in the AD etiology, clinical trials with antioxidant therapies have not produced consistent results. In this review, we will discuss the role of oxidative stress in synaptic dysfunction in AD, innovative therapeutic strategies evolved based on a better understanding of the complexity of molecular mechanisms of AD, and the dual role ROS play in health and disease.

Sulfur amino acid restriction-induced changes in redox-sensitive proteins are associated with slow protein synthesis rates

The mechanisms underlying life span extension by sulfur amino acid restriction (SAAR) are unclear. Cysteine and methionine are essential for the biosynthesis of proteins and glutathione (GSH), a major redox buffer in the endoplasmic reticulum (ER). We hypothesized that SAAR alters protein synthesis by modulating the redox milieu. Male F344-rats were fed control (CD: 0.86% methionine without cysteine) and SAAR diets (0.17% methionine without cysteine) for 12 weeks. Growth rates, food intake, cysteine and GSH levels, proteins associated with redox status and translation, and fractional protein synthesis rates (FSRs) were determined in liver. Despite a 40% higher food intake, growth rates for SAAR rats were 27% of those fed CD. Hepatic free cysteine in SAAR rats was 55% compared with CD rats. SAAR altered tissue distribution of GSH, as hepatic and erythrocytic levels were 56% and 196% of those in CD rats. Lower GSH levels did not induce ER stress (i.e., unchanged expression of Xbp1_s , Chop, and Grp78), but activated PERK and its substrates eIF2-α and NRF2. SAAR-induced changes in translation-initiation machinery (higher p-eIF2-α and 4E-BP1, and lower eIF4G-1) resulted in slower protein synthesis rates (53% of CD). Proteins involved in the antioxidant response (NRF2, KEAP1, GCLM, and NQO1) and protein folding (PDI and ERO1-α) were increased in SAAR. Lower FSR and efficient protein folding might be improving proteostasis in SAAR.

Involvement of autophagy in the beneficial effects of resveratrol in hepatic steatosis treatment. A comparison with energy restriction

Involvement of autophagy in the liver delipidating effects of resveratrol and energy restriction.

Neuregulin-1 protects mouse cerebellum against oxidative stress and neuroinflammation

Cerebellum undergoes degenerative changes in neurodegenerative diseases. Two main factors including oxidative stress and neuroinflammation mediate neurodegeneration. Neuregulin-1 (Nrg1) has been implicated in many neurodegenerative diseases, while the underlying mechanisms are unknown. We hypothesized that Nrg1 prevents oxidative stress and neuroinflammation in neurodegeneration. We found a positive correlation between Nrg1 protein levels and ErbB4 and ErbB2 receptor phosphorylation in microarrays of normal human cerebellar tissue. In addition, Nrg1 was also co-localized with pErbB4 and pErbB2. Primary mouse cerebellar granule neurons (CGNs) were treated with H₂O₂ or LPS combined with recombinant Nrg1β (rNrg1β). Western blot analysis and immunofluorescence revealed that H₂O₂ and LPS-induced neuronal toxicity down-regulated the activation of ErbB receptors and Akt1, and the ratio of Bcl2/Bax, which was reversed by rNrg1β. In vivo studies showed that LPS-induced neuroinflammation in mouse cerebellum down-regulated pErbB4, pErbB2, pAkt1/Akt1 and Bcl2/Bax levels, whereas rNrg1β treatment reversed the changes. Immunohistochemistry and Western blot analysis showed that rNrg1β alleviates neuroinflammation by reducing the number of microglial cells and astrocytes and the expression of IL1β. Our results indicate that Nrg1 protects against oxidative stress and neuroinflammation in mouse cerebellum, suggesting potential therapeutic application in neuroinflammation associated with neurodegenerative diseases.

Correlation between Cholinergic Innervation, Autophagy, and Etiopathology of Benign Prostatic Hyperplasia

BACKGROUND

Whether cholinergic innervations and/or autophagy have a role in the etiopathology of benign prostatic hyperplasia (BPH) is still unknown. This study aimed to investigate the role of cholinergic innervation and autophagy in the etiopathology of BPH.

METHODS

Male, 13-week-old spontaneous hypertension rats (spontaneous BPH animal model) were divided into three groups: an experimental group (EG, n = 24), a control group (CG, n = 24), and a normal control group (NC, n = 10). The EG animals were intragastrically injected with tolterodine (3.5 mg/kg, twice a day), CG animals were intragastrically injected with physiological saline, and the NC animals did not receive any treatment. Rats were sacrificed every 4 weeks, and the prostatic gross morphological changes, wet weight/body weight (ww/bw), dry weight/wet weight (dw/ww), histological changes, ultrastructural changes, and LC3 immunohistochemistry were continuously observed and compared.

RESULTS

The gross morphological and ww/bw changes in the three groups were similar at every stage. The dw/ww (mg/mg) values of the EG at week 17, 21, 25, and 29 were 0.1478 ± 0.0034, 0.1653 ± 0.0036, 0.1668 ± 0.0045, and 0.1755 ± 0.0034, respectively, and the CG values were 0.1511 ± 0.0029, 0.1734 ± 0.0020, 0.1837 ± 0.0052, and 0.1968 ± 0.0045, respectively. The difference between EG and CG for dw/ww showed statistical significance after 21 weeks of age (week 21: P= 0.016, week 25: P= 0.008, and week 29: P= 0.001). Both EG and CG, prostatic glandular epithelial cell proliferation, and secretory function improved with age, but in EG, these improvements were slower than those in CG, and all the differences were statistically significant after 21 weeks. An increasing number of autophagosomes in the prostatic glandular cell cytoplasm, attenuation of LC3-I immunohistochemical staining, enhancement of LC3-II staining, and the ratio of LC3-II/LC3-I staining were all progressive in both groups, but the rate of change in EG was faster than that in CG, and these differences gained statistical significance after 25 weeks. Comparisons with regard to the above indexes between CG and NC showed no statistical significance at any stage.

CONCLUSIONS

Cholinergic innervations and activation of autophagy appear to have important functions in the etiopathology of BPH. Drug-mediated blockade of cholinergic innervations could delay the physiopathology processes. Moreover, overactivation of autophagy may also play an important role in this delay.

GRP78 at the Centre of the Stage in Cancer and Neuroprotection

The 78-kDa glucose-regulated protein GRP78, also known as BiP and HSP5a, is a multifunctional protein with activities far beyond its well-known role in the unfolded protein response (UPR) which is activated after endoplasmic reticulum (ER) stress in the cells. Most of these newly discovered activities depend on its position within the cell. GRP78 is located mainly in the ER, but it has also been observed in the cytoplasm, the mitochondria, the nucleus, the plasma membrane, and secreted, although it is dedicated mostly to engage endogenous cytoprotective processes. Hence, GRP78 may control either UPR and macroautophagy or may activated phosphatidylinositol 3-kinase (PI3K)/AKT pro-survival pathways. GRP78 influences how tumor cells survive, proliferate, and develop chemoresistance. In neurodegeneration, endogenous mechanisms of neuroprotection are frequently insufficient or dysregulated. Lessons from tumor biology may give us clues about how boosting endogenous neuroprotective mechanisms in age-related neurodegeneration. Herein, the functions of GRP78 are revealed at the center of the stage of apparently opposite sites of the same coin regarding cytoprotection: neurodegeneration and cancer. The goal is to give a comprehensive and critical review that may serve to guide future experiments to identify interventions that will enhance neuroprotection.

Dietary restriction protects against diethylnitrosamine-induced hepatocellular tumorigenesis by restoring the disturbed gene expression profile

Hepatocellular carcinoma (HCC) is one of the most lethal and prevalent malignancies, worse still, there are very limited therapeutic measures with poor clinical outcomes. Dietary restriction (DR) has been known to inhibit spontaneous and induced tumors in several species, but the mechanisms are little known. In the current study, by using a diethylnitrosamine (DEN)-induced HCC mice model, we found that DR significantly reduced the hepatic tumor number and size, delayed tumor development, suppressed proliferation and promoted apoptosis. Further transcriptome sequencing of liver tissues from the DEN and the DEN accompanied with DR (DEN+DR) mice showed that DEN induced profound changes in the gene expression profile, especially in cancer-related pathways while DR treatment reversed most of the disturbed gene expression induced by DEN. Finally, transcription factor enrichment analysis uncovered the transcription factor specificity protein 1 (SP1) probably functioned as the main regulator of gene changes, orchestrating the protective effects of DR on DEN induced HCC. Taken together, by the first comprehensive transcriptome analysis, we elucidate that DR protects aginst DEN-induced HCC by restoring the disturbed gene expression profile, which holds the promise to provide effective molecular targets for cancer therapies.

The role of SUMOylation in ageing and senescent decline

Posttranslational protein modifications are playing crucial roles in essential cellular mechanisms. SUMOylation is a reversible posttranslational modification of specific target proteins by the attachment of a small ubiquitin-like protein. Although the mechanism of conjugation of SUMO to proteins is analogous to ubiquitination, it requires its own, specific set of enzymes. The consequences of SUMOylation are widely variable, depending on the physiological state of the cell and the attached SUMO isoform. Accumulating recent findings have revealed a prominent role of SUMOylation in molecular pathways that govern senescence and ageing. Here, we review the link between SUMO attachment events and cellular processes that influence senescence and ageing, including promyelocytic leukaemia (PML) nuclear body and telomere function, autophagy, reactive oxygen species (ROS) homeostasis and growth factor signalling.

Licorice extract attenuates brain aging of d-galactose induced rats through inhibition of oxidative stress and attenuation of neuronal apoptosis

A potential protective mechanism of licorice for d-galactose induced aging in rats.