Switching from high-fat diet to foods containing resveratrol as a calorie restriction mimetic changes the architecture of arcuate nucleus to produce more newborn anorexigenic neurons

The role of resveratrol in neurogenesis: a systematic review

CONTEXT

Resveratrol (RV) is a natural compound found in grapes, wine, berries, and peanuts and has potential health benefits-namely, neurogenesis improvement. Neurogenesis, which is the process through which new neurons or nerve cells are generated in the brain, occurs in the subventricular zone and hippocampus and is influenced by various factors. RV has been shown to increase neural stem cell proliferation and survival, improving cognitive function in hippocampus-dependent tasks. Thus, to provide a convergent and unbiased conclusion of the available evidence on the correlation between the RV and neurogenesis, a systematic review needs to be undertaken meticulously and with appropriate attention.

OBJECTIVE

This study aimed to systematically review any potential connection between the RV and neurogenesis in animal models.

DATA SOURCES AND EXTRACTION

Based on the particular selection criteria, 8 original animal studies that investigated the relationship between RV and neurogenesis were included. Studies written in English and published in peer-reviewed journals with no restrictions on the starting date of publication on August 17, 2023, were searched in the Google Scholar and PubMed databases. Furthermore, data were extracted and analyzed independently by 2 researchers and then reviewed by a third researcher, and discrepancies were resolved by consensus. This project followed PRISMA reporting standards.

DATA ANALYSIS

In the studies analyzed in this review, there is a definite correlation between RV and neurogenesis, meaning that RV intake, irrespective of the mechanisms thereof, can boost neurogenesis in both the subventricular zone and hippocampus.

CONCLUSION

This finding, albeit with some limitations, provides a plausible indication of RV's beneficial function in neurogenesis. Indeed, RV intake may result in neurogenesis benefits-namely, cognitive function, mood regulation, stress resilience, and neuroprotection, potentially preventing cognitive decline.

Resveratrol Alleviates NEFA-Induced Oxidative Damage in Bovine Mammary Epithelial Cells by Restoring Mitochondrial Function

In periparturient dairy cows, high non-esterified fatty acids (NEFAs) caused by a severe negative energy balance induce oxidative stress and metabolic dysfunction, which pose a severe challenge to the dairy industry. Resveratrol (RES) is a polyphenolic compound with antioxidant, anti-inflammatory and multiple other physiological effects. However, its effect on oxidative damage triggered by NEFAs in bovine mammary epithelial cells is rarely reported. This study aimed to investigate the antioxidant effects and underlying molecular mechanisms of RES in NEFA-challenged BMECs. The results showed that RES ameliorated NEFA-induced oxidative damage by upregulating antioxidant enzyme expression and reducing malondialdehyde (MDA) and reactive oxygen species (ROS). Furthermore, exogenous NEFAs resulted in a decrease in mitochondrial membrane potential (MMP), cellular adenosine triphosphate (ATP) production, energy metabolism (NAD+/NADH ratio), abnormal mitochondrial structure and an increase in apoptosis levels. RES treatment restored mitochondrial function in NEFA-stressed BMECs, as evidenced by the increase in MMP, ATP generation and NAD+/NADH ratio accompanying the decline in mitochondrial structural abnormalities and cell apoptosis. In addition, in vivo studies in a mouse model of oxidative damage induced by high-fat diet (HFD) demonstrated that RES alleviated oxidative damage (decreased MDA content) and mitochondrial dysfunction (decreased expression of Drp1 and Fis1 and increased levels of Mfn2, Cyt C mRNA and ATP production) in mammary gland tissue. Overall, these findings suggested that RES could alleviate NEFA-induced oxidative damage in BMECs by modulating mitochondrial function, thereby contributing to the prevention and treatment of oxidative damage in perinatal dairy cows with a negative energy balance.

Management of inflammaging in kidney diseases: focusing on the current investigational drugs

INTRODUCTION

To improve kidney disease treatments, it is crucial to understand how inflammaging affects patients´ longevity. We could potentially slow down kidney disease progression and enhance longevity by targeting specific pathways involved in inflammaging with potential drugs.

AREAS OF COVERED

This review offers an updated overview of 'anti-inflammaging' drugs currently in the kidney disease research pipeline, as well as those with potential for future therapeutic use. Furthermore, these drugs are categorized according to their mechanisms, including targeting inflammation, immune and metabolic regulation, oxidative stress, senescence, and autophagy, as demonstrated in preclinical and early clinical trials. Additionally, the review provides insights into key challenges and opinions for future advancements in this field.

EXPERT OPINION

We reviewed recent advancements in applying different therapies to mitigate inflammaging in kidney diseases. We underscore the need for continued research to elucidate the complex pathways underlying inflammaging, which will be essential for the development of more precise and effective treatments. As research in this field advances, several emerging drugs appear promising for future investigation. While current findings are encouraging, further clinical studies are required to validate the therapeutic potential of these agents in kidney diseases, ultimately paving the way for more targeted and efficacious interventions.

Leptin receptor reactivation restores brain function in early-life Lepr-deficient mice

Obesity is a chronic disease caused by excessive fat accumulation that impacts the body and brain health. Insufficient leptin or leptin receptor (LepR) is involved in the disease pathogenesis. Leptin is involved with several neurological processes, and it has crucial developmental roles. We have previously demonstrated that leptin deficiency in early life leads to permanent developmental problems in young adult mice, including an imbalance in energy homeostasis, alterations in melanocortin and the reproductive system and a reduction in brain mass. Given that in humans, obesity has been associated with brain atrophy and cognitive impairment, it is important to determine the long-term consequences of early-life leptin deficiency on brain structure and memory function. Here, we demonstrate that leptin-deficient (LepOb) mice exhibit altered brain volume, decreased neurogenesis and memory impairment. Similar effects were observed in animals that do not express the LepR (LepRNull). Interestingly, restoring the expression of LepR in 10-week-old mice reverses brain atrophy, in addition to neurogenesis and memory impairments in older animals. Our findings indicate that leptin deficiency impairs brain development and memory, which are reversible by restoring leptin signalling in adulthood.

Resveratrol Mediated Regulation of Hippocampal Neuroregenerative Plasticity via SIRT1 Pathway in Synergy with Wnt Signaling: Neurotherapeutic Implications to Mitigate Memory Loss in Alzheimer's Disease

Alzheimer's disease (AD) is a major form of dementia. Abnormal amyloidogenic event-mediated degeneration of cholinergic neurons in the cognitive centers of the brain has been attributed to neuropathological sequelae and behavioral deficits in AD. Besides, impaired adult neurogenesis in the hippocampus has experimentally been realized as an underlying cause of dementia regardless of neurodegeneration. Therefore, nourishing the neurogenic process in the hippocampus has been considered an effective therapeutic strategy to mitigate memory loss. In the physiological state, the Wnt pathway has been identified as a potent mitogenic generator in the hippocampal stem cell niche. However, downstream components of Wnt signaling have been noticed to be downregulated in AD brains. Resveratrol (RSV) is a potent Sirtuin1 (SIRT1) enhancer that facilitates neuroprotection and promotes neurogenesis in the hippocampus of the adult brain. While SIRT1 is an important positive regulator of Wnt signaling, ample reports indicate that RSV treatment strongly mediates the fate determination of stem cells through Wnt signaling. However, the possible therapeutic roles of RSV-mediated SIRT1 enhancement on the regulation of hippocampal neurogenesis and reversal of memory loss through the Wnt signaling pathway have not been addressed yet. Taken together, this review describes RSV-mediated effects on the regulation of hippocampal neurogenesis via the activation of SIRT1 in synergy with the Wnt signaling. Further, the article emphasizes a hypothesis that RSV treatment can provoke the activation of quiescent neural stem cells and prime their neurogenic capacity in the hippocampus via Wnt signaling in AD.

A Short-Term Sucrose Diet Impacts Cell Proliferation of Neural Precursors in the Adult Hypothalamus

Radial glia-like cells in the hypothalamus and dorsal vagal complex are neural precursors (NPs) located near subventricular organs: median eminence and area postrema, respectively. Their strategic position can detect blood-borne nutrients, hormones, and mitogenic signals. Hypothalamic NPs increase their proliferation with a mechanism that involves hemichannel (HC) activity. NPs can originate new neurons in response to a short-term high-fat diet as a compensatory mechanism. The effects of high carbohydrate Western diets on adult neurogenesis are unknown. Although sugars are usually consumed as sucrose, more free fructose is now incorporated into food items. Here, we studied the proliferation of both types of NPs in Sprague Dawley rats exposed to a short-term high sucrose diet (HSD) and a control diet. In tanycyte cultures, we evaluated the effects of glucose and fructose and a mix of both hexoses on HC activity. In rats fed an HSD, we observed an increase in the proliferative state of both precursors. Glucose, either in the presence or absence of fructose, but not fructose alone, induced in vitro HC activity. These results should broaden the understanding of the nutrient monitoring capacity of NPs in reacting to changes in feeding behavior, specifically to high sugar western diets.

Neurogenesis in aging and age-related neurodegenerative diseases

Adult neurogenesis, the process by which neurons are generated in certain areas of the adult brain, declines in an age-dependent manner and is one potential target for extending cognitive healthspan. Aging is a major risk factor for neurodegenerative diseases and, as lifespans are increasing, these health challenges are becoming more prevalent. An age-associated loss in neural stem cell number and/or activity could cause this decline in brain function, so interventions that reverse aging in stem cells might increase the human cognitive healthspan. In this review, we describe the involvement of adult neurogenesis in neurodegenerative diseases and address the molecular mechanistic aspects of neurogenesis that involve some of the key aggregation-prone proteins in the brain (i.e., tau, Aβ, α-synuclein, …). We summarize the research pertaining to interventions that increase neurogenesis and regulate known targets in aging research, such as mTOR and sirtuins. Lastly, we share our outlook on restoring the levels of neurogenesis to physiological levels in elderly individuals and those with neurodegeneration. We suggest that modulating neurogenesis represents a potential target for interventions that could help in the fight against neurodegeneration and cognitive decline.

An integrated chemo-informatics and in vitro experimental approach repurposes acarbose as a post-ischemic neuro-protectant

The increasing prevalence of ischemic stroke combined with limited therapeutic options highlights the compelling need for continued research into the development of future neuro-therapeutics. Death-Associated Protein Kinase 1 (DAPK1) and p53 protein-protein interaction serve as a signaling point for the convergence of apoptosis and necrosis in cerebral ischemia. In this study, we used an integrated chemo-informatics and in vitro experimental drug repurposing strategy to screen potential small-molecule inhibitors of DAPK1-p53 interaction from the United States of America Food and Drug Administration (FDA) approved drug database exhibiting post-ischemic neuroprotective and neuro-regenerative efficacy and mechanisms. The computational docking and molecular dynamics simulation of FDA-approved drugs followed by an in vitro experimental validation identified acarbose, an anti-diabetic medication and caloric restriction mimetic as a potential inhibitor of DAPK1-p53 interaction. The evaluation of post-ischemic neuroprotective and regenerative efficacy and mechanisms of action for acarbose was carried out using a set of experimental methods, including cell viability, proliferation and differentiation assays, fluorescence staining, and gene expression analysis. Post-ischemic administration of acarbose conferred significant neuroprotection against ischemia-reperfusion injury in vitro. The reduced fluorescence emission in cells stained with _pS²⁰ supported the potential of acarbose in inhibiting the DAPK1-p53 interaction. Acarbose prevented mitochondrial and lysosomal dysfunction, and favorably modulated gene expression related to cell survival, inflammation, and regeneration. BrdU staining and neurite outgrowth assay showed a significant increase in cell proliferation and differentiation in acarbose-treated group. This is the first study known to provide mechanistic insight into the post-ischemic neuroprotective and neuro-regenerative potential of acarbose. Our results provide a strong basis for preclinical studies to evaluate the safety and neuroprotective efficacy of acarbose against ischemic stroke.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-022-03130-5.

Hypothalamic Expression of Neuropeptide Y (NPY) and Pro-OpioMelanoCortin (POMC) in Adult Male Mice Is Affected by Chronic Exposure to Endocrine Disruptors

In the arcuate nucleus, neuropeptide Y (NPY) neurons, increase food intake and decrease energy expenditure, and control the activity of pro-opiomelanocortin (POMC) neurons, that decrease food intake and increase energy expenditure. Both systems project to other hypothalamic nuclei such as the paraventricular and dorsomedial hypothalamic nuclei. Endocrine disrupting chemicals (EDCs) are environmental contaminants that alter the endocrine system causing adverse health effects in an intact organism or its progeny. We investigated the effects of long-term exposure to some EDCs on the hypothalamic NPY and POMC systems of adult male mice that had been previously demonstrated to be a target of some of these EDCs after short-term exposure. Animals were chronically fed for four months with a phytoestrogen-free diet containing two different concentrations of bisphenol A, diethylstilbestrol, tributyltin, or E₂. At the end, brains were processed for NPY and POMC immunohistochemistry and quantitatively analyzed. In the arcuate and dorsomedial nuclei, both NPY and POMC immunoreactivity showed a statistically significant decrease. In the paraventricular nucleus, only the NPY system was affected, while the POMC system was not affected. Finally, in the VMH the NPY system was affected whereas no POMC immunoreactive material was observed. These results indicate that adult exposure to different EDCs may alter the hypothalamic circuits that control food intake and energy metabolism.

Toll-Like Receptor Signaling Pathways: Novel Therapeutic Targets for Cerebrovascular Disorders

Toll-like receptors (TLRs), a class of pattern recognition proteins, play an integral role in the modulation of systemic inflammatory responses. Cerebrovascular diseases (CVDs) are a group of pathological conditions that temporarily or permanently affect the brain tissue mostly via the decrease of oxygen and glucose supply. TLRs have a critical role in the activation of inflammatory cascades following hypoxic-ischemic events and subsequently contribute to neuroprotective or detrimental effects of CVD-induced neuroinflammation. The TLR signaling pathway and downstream cascades trigger immune responses via the production and release of various inflammatory mediators. The present review describes the modulatory role of the TLR signaling pathway in the inflammatory responses developed following various CVDs and discusses the potential benefits of the modulation of different TLRs in the improvement of functional outcomes after brain ischemia.

Maternal-infant nutrition and development programming of offspring appetite and obesity

In the United States and Mexico, the obesity epidemic represents a significant public health problem. Although obesity is often attributed to a Western-style, high-fat diet and decreased activity, there is now compelling evidence that this, in part, occurs because of the developmental programming effects resulting from exposure to maternal overnutrition. Human and animal studies demonstrate that maternal obesity and high-fat diet result in an increased risk for childhood and adult obesity. The potential programming effects of obesity have been partly attributed to hyperphagia, which occurs as a result of increased appetite with reduced satiety neuropeptides or neurons. However, depending on maternal nutritional status during the nursing period, the programmed hyperphagia and obesity can be exacerbated or prevented in offspring born to obese mothers. The underlying mechanism of this phenomenon likely involves the plasticity of the appetite regulatory center and thus presents an opportunity to modulate feeding and satiety regulation and break the obesity cycle.

Hypothalamic neurogenesis and its implications for obesity-induced anxiety disorders

Obesity and anxiety are public health problems that have no effective cure. Obesity-induced anxiety is also the most common behavioural trait exhibited amongst obese patients, with the mechanisms linking these disorders being poorly understood. The hypothalamus and hippocampus are reciprocally connected, important neurogenic brain regions that could be vital to understanding these disorders. Dietary, physical activity and lifestyle interventions have been shown to be able to enhance neurogenesis within the hippocampus, while the effects thereof within the hypothalamus is yet to be ascertained. This review describes hypothalamic neurogenesis, its impairment in obesity as well as the effect of interventional therapies. Obesity is characterized by a neurogenic shift towards neuropeptide Y neurons, promoting appetite and weight gain. While, nutraceuticals and exercise promote proopiomelanocortin neuron proliferation, causing diminished appetite and reduced weight gain. Through the furthered development of multimodal approaches targeting both these brain regions could hold an even greater therapeutic potential.

The FGF2-induced tanycyte proliferation involves a connexin 43 hemichannel/purinergic-dependent pathway

In the adult hypothalamus, the neuronal precursor role is attributed to the radial glia-like cells that line the third-ventricle (3V) wall called tanycytes. Under nutritional cues, including hypercaloric diets, tanycytes proliferate and differentiate into mature neurons that moderate body weight, suggesting that hypothalamic neurogenesis is an adaptive mechanism in response to metabolic changes. Previous studies have shown that the tanycyte glucosensing mechanism depends on connexin-43 hemichannels (Cx43 HCs), purine release, and increased intracellular free calcium ion concentration [(Ca²⁺ )_i ] mediated by purinergic P2Y receptors. Since, Fibroblast Growth Factor 2 (FGF2) causes similar purinergic events in other cell types, we hypothesize that this pathway can be also activated by FGF2 in tanycytes to promote their proliferation. Here, we used bromodeoxyuridine (BrdU) incorporation to evaluate if FGF2-induced tanycyte cell division is sensitive to Cx43 HC inhibition in vitro and in vivo. Immunocytochemical analyses showed that cultured tanycytes maintain the expression of in situ markers. After FGF2 exposure, tanycytic Cx43 HCs opened, enabling release of ATP to the extracellular milieu. Moreover, application of external ATP was enough to induce their cell division, which could be suppressed by Cx43 HC or P2Y1-receptor inhibitors. Similarly, in vivo experiments performed on rats by continuous infusion of FGF2 and a Cx43 HC inhibitor into the 3V, demonstrated that FGF2-induced β-tanycyte proliferation is sensitive to Cx43 HC blockade. Thus, FGF2 induced Cx43 HC opening, triggered purinergic signaling, and increased β-tanycytes proliferation, highlighting some of the molecular mechanisms involved in the cell division response of tanycyte. This article has an Editorial Highlight see https://doi.org/10.1111/jnc.15218.