The Beneficial Roles of SIRT1 in Neuroinflammation-Related Diseases

Epigenetic Biomarkers as Diagnostic Tools for Neurodegenerative Disorders

Epigenetics is the study of heritable changes in gene expression that occur without alterations to the DNA sequence, linking the genome to its surroundings. The accumulation of epigenetic alterations over the lifespan may contribute to neurodegeneration. The aim of the present study was to identify epigenetic biomarkers for improving diagnostic efficacy in patients with neurodegenerative diseases. We analyzed global DNA methylation, chromatin remodeling/histone modifications, sirtuin (SIRT) expression and activity, and the expression of several important neurodegeneration-related genes. DNA methylation, SIRT expression and activity and neuregulin 1 (NRG1), microtubule-associated protein tau (MAPT) and brain-derived neurotrophic factor (BDNF) expression were reduced in buffy coat samples from patients with neurodegenerative disorders. Our data suggest that these epigenetic biomarkers may be useful in clinical practical for the diagnosis, surveillance, and prognosis of disease activity in patients with neurodegenerative diseases.

Novel mechanistic insights towards the repositioning of alogliptin in Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disease that impairs people's lives tremendously. The development of innovative treatment modalities for PD is a significant unmet medical need. The critical function of glucagon-like peptide-1 (GLP-1) in neurodegenerative diseases has raised impetus in investigating the repositioning of a dipeptidyl peptidase IV inhibitor, alogliptin (ALO), as an effective treatment for PD. As a result, the focus of this research was to assess the effect of ALO in a rat rotenone (ROT) model of PD. For 21 days, ROT (1.5 mg/kg) was delivered subcutaneously every other day. ALO (30 mg/kg/day), delivered by gavage for 21 days, recovered motor performance and improved motor coordination in the open-field and rotarod testing. These impacts were highlighted by restoring striatal dopamine content and correcting histological changes that occurred concurrently. The ALO molecular signaling was determined by increasing the quantity of GLP-1 and the protein expression of its downstream signaling pathway, pT172-AMPK/SIRT1/PGC-1α. Furthermore, it curbed neuroinflammation via hampering HMGB1/TLR4/NLRP3 inflammasome activation and conquered striatal microglia activation. Pre-administration of dorsomorphin reversed the neuroprotective effects. In conclusion, the promising neuroprotective effect of ALO highlights the repositioning of ALO as a prospective revolutionary candidate for combating PD.

The Regulation Effect of α7nAChRs and M1AChRs on Inflammation and Immunity in Sepsis

The inflammatory storm in the early stage and immunosuppression in the late stage are responsible for the high mortality rates and multiple organ dysfunction in sepsis. In recent years, studies have found that the body's cholinergic system can spontaneously and dynamically regulate inflammation and immunity in sepsis according to the needs of the body. Firstly, the vagus nerve senses and regulates local or systemic inflammation by means of the Cholinergic Anti-inflammatory Pathway (CAP) and activation of α7-nicotinic acetylcholine receptors (α7nAChRs); thus, α7nAChRs play important roles for the central nervous system (CNS) to modulate peripheral inflammation; secondly, the activation of muscarinic acetylcholine receptors 1 (M1AChRs) in the forebrain can affect the neurons of the Medullary Visceral Zone (MVZ), the core of CAP, to regulate systemic inflammation and immunity. Based on the critical role of these two cholinergic receptor systems in sepsis, it is necessary to collect and analyze the related findings in recent years to provide ideas for further research studies and clinical applications. By consulting the related literature, we draw some conclusions: MVZ is the primary center for the nervous system to regulate inflammation and immunity. It coordinates not only the sympathetic system and vagus system but also the autonomic nervous system and neuroendocrine system to regulate inflammation and immunity; α7nAChRs are widely expressed in immune cells, neurons, and muscle cells; the activation of α7nAChRs can suppress local and systemic inflammation; the expression of α7nAChRs represents the acute or chronic inflammatory state to a certain extent; M1AChRs are mainly expressed in the advanced centers of the brain and regulate systemic inflammation; neuroinflammation of the MVZ, hypothalamus, and forebrain induced by sepsis not only leads to their dysfunctions but also underlies the regulatory dysfunction on systemic inflammation and immunity. Correcting the neuroinflammation of these regulatory centers and adjusting the function of α7nAChRs and M1AChRs may be two key strategies for the treatment of sepsis in the future.

The protective effects of activating Sirt1/NF-κB pathway for neurological disorders

Sirt1, a member of the sirtuins family, is a nicotinamide adenosine dinucleotide (NAD⁺)-dependent deacetylase. It can be involved in the regulation of several processes including inflammatory response, apoptosis, oxidative stress, energy metabolism, and autophagy by exerting deacetylation. Nuclear factor-κB (NF-κB), a crucial nuclear transcription factor with specific DNA binding sequences, exists in almost all cells and plays a vital role in several biological processes involving inflammatory response, immune response, and apoptosis. As the hub of multiple intracellular signaling pathways, the activity of NF-κB is regulated by multiple factors. Sirt1 can both directly deacetylate NF-κB and indirectly through other molecules to inhibit its activity. We would like to emphasize that Sirt1/NF-κB is a signaling pathway that is closely related to neuroinflammation. Many recent studies have demonstrated the neuroprotective effects of Sirt1/NF-κB signaling pathway activation applied to the treatment of neurological related diseases. In this review, we focus on new advances in the neuroprotective effects of the Sirt1/NF-κB pathway. First, we briefly review Sirt1 and NF-κB, two key molecules of cellular metabolism. Next, we discuss the connection between NF-κB and neuroinflammation. In addition, we explore how Sirt1 regulates NF-κB in nerve cells and relevant evidence. Finally, we analyze the therapeutic effects of the Sirt1/NF-κB pathway in several common neuroinflammation-related diseases.

Regulation of Sirt1 on energy metabolism and immune response in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease. Synovial hyperplasia and persistent inflammation serve as its typical pathological manifestations, which ultimately lead to joint destruction and function loss. Both clinical observations and metabolomics studies have revealed the prevalence of metabolic disorders in RA. In inflammatory immune microenvironments, energy metabolism is profoundly changed. Increasingly evidences suggest that this abnormality is involved in the occurrence and development of RA-related inflammation. Unsurprisingly, many energy metabolism sensors have been confirmed with immunoregulatory properties. As a representative, silent information regulator type 1 (Sirt1) controls many aspects of immune cells, such as cell lifespan, polarization, and secretion by functioning as a transcriptional regulator. Because of the profound clinical implication, researches on Sirt1 in the regulation of energy metabolism and immune functions under RA conditions have gradually gained momentum. This signaling balances glycolysis, lipid metabolism and insulin secretion orchestrating with other metabolism sensors, and consequently affects immune milieu through a so-called metabolism-immune feedback mechanism. This article reviews the involvement of Sirt1 in RA by discussing its impacts on energy metabolism and immune functions, and specially highlights the potential of Sirt1-targeting anti-rheumatic regimens. It also provides a theoretical basis for clarifying the mystery about the high incidence of metabolic complications in RA patients and identifying new anti-rheumatic reagents.

Role of SIRT1 in Hepatic Encephalopathy: In Vivo and In Vitro Studies Focusing on the NLRP3 Inflammasome

Hepatic encephalopathy (HE) is a neuropsychiatric disorder resulting from acute or chronic liver failure. This study is aimed at investigating the therapeutic effects and mechanisms of SIRT1 in thioacetamide- (TAA-) induced rat HE models. A selective activator (CAY10602) and inhibitor (EX527) of SIRT1 were used in this study. All male rats were separated into control, TAA, CAY10602+TAA, and EX527+TAA groups. Histological damage, liver function, serum ammonia, behavioral changes, and brain oxidative stress were measured in each group. Western blotting was used to measure SIRT1, NLRP3, ASC, and IL-1β protein expression. The results showed that CAY10602 alleviated liver injury, improved neurological decline, reduced microglial activation and brain oxidative stress, and improved the survival rates of HE rats. Moreover, CAY10602 inhibited activation of the NLRP3 inflammasome in microglia of the brain cortex in HE rats. Next, cell experiments confirmed that CAY10602 inhibited activation of the NLRP3 inflammasome in BV2 microglial cells. However, inhibition of SIRT1 by EX527 or lentivirus could enhance activation of the NLRP3 inflammasome in this process. Finally, CAY10602 reduced the neurotoxicity induced by high levels of ammonia in HT22 cells. Taken together, CAY10602 alleviates TAA-induced HE by suppressing microglial activation and the NLRP3 inflammasome and reducing the neurotoxicity of NH₄Cl in HT22 cells. A pharmacologic activator of SIRT1 may be a promising approach for the treatment of HE.

Relieving Cellular Energy Stress in Aging, Neurodegenerative, and Metabolic Diseases, SIRT1 as a Therapeutic and Promising Node

The intracellular energy state will alter under the influence of physiological or pathological stimuli. In response to this change, cells usually mobilize various molecules and their mechanisms to promote the stability of the intracellular energy status. Mitochondria are the main source of ATP. Previous studies have found that the function of mitochondria is impaired in aging, neurodegenerative diseases, and metabolic diseases, and the damaged mitochondria bring lower ATP production, which further worsens the progression of the disease. Silent information regulator-1 (SIRT1) is a multipotent molecule that participates in the regulation of important biological processes in cells, including cellular metabolism, cell senescence, and inflammation. In this review, we mainly discuss that promoting the expression and activity of SIRT1 contributes to alleviating the energy stress produced by physiological and pathological conditions. The review also discusses the mechanism of precise regulation of SIRT1 expression and activity in various dimensions. Finally, according to the characteristics of this mechanism in promoting the recovery of mitochondrial function, the relationship between current pharmacological preparations and aging, neurodegenerative diseases, metabolic diseases, and other diseases was analyzed.

Sirt1 inhibits kidney stones formation by attenuating calcium oxalate-induced cell injury

Cell injury is a necessary and critical event during CaOx kidney stone formation. Sirt1 exerts a number of pleiotropic effects, protecting against renal cell injury. This study aims to explore the relationship between Sirt1 and CaOx kidney stone formation and the underlying mechanism. Sirt1 expression in renal tissues or HK-2 cells was detected by Western blot, immunohistochemistry and immunofluorescence. Apoptosis in renal tissues was examined by TUNEL staining. Renal pathological changes and the crystals deposition were detected by hematoxylin-eosin and Von Kossa staining. Crystal-cell adhesion and cell injury in HK-2 cells were assessed by atomic absorption spectrometry and flow cytometry, respectively. Sirt1 expression in nephrolithiasis patients was downregulated and the level of apoptosis was increased. Further study found that Sirt1 expression was decreased in both in vivo and in vitro models. Interestingly, the levels of cell injury were elevated in vivo and in vitro models. Suppressing Sirt1 expression promoted COM-induced crystal-cell adhesion and exacerbated cell injury. In contrast, increasing the expression of Sirt1 by lentivirus transfection in vitro and resveratrol administration in vivo, alleviated crystal deposition and cell damage. Our findings suggest that Sirt1 could inhibit kidney stone formation, at least in part, through attenuating CaOx -induced cell injury.

Saffron extract attenuates neuroinflammation in rmTBI mouse model by suppressing NLRP3 inflammasome activation via SIRT1

Traumatic brain injury (TBI) remains a major cause of morbidity and disability worldwide and a healthcare burden. TBI is an important risk factor for neurodegenerative diseases hallmarked by exacerbated neuroinflammation. Neuroinflammation in the cerebral cortex plays a critical role in secondary injury progression following TBI. The NOD-like receptors (NLR) family pyrin domain containing 3 (NLRP3) inflammasome is a key player in initiating the inflammatory response in various central nervous system disorders entailing TBI. This current study aims to investigate the role of NLRP3 in repetitive mild traumatic brain injury (rmTBI) and identify the potential neuroprotective effect of saffron extract in regulating the NLRP3 inflammasome. 24 hours following the final injury, rmTBI causes an upregulation in mRNA levels of NLRP3, caspase-1, the apoptosis-associated speck-like protein containing a CARD (ASC), nuclear factor kappa B (NF-κB), interleukin-1Beta (IL-1β), interleukin 18 (IL-18), nuclear factor erythroid 2-related factor 2 (NRF2) and heme oxygenase 1 (HMOX1). Protein levels of NLRP3, sirtuin 1 (SIRT1), glial fibrillary acidic protein (GFAP), ionized calcium-binding adaptor molecule 1 (Iba1), and neuronal nuclei (Neu N) also increased after rmTBI. Administration of saffron alleviated the degree of TBI, as evidenced by reducing the neuronal damage, astrocyte, and microglial activation. Pretreatment with saffron inhibited the activation of NLRP3, caspase-1, and ASC concurrent to reduced production of the inflammatory cytokines IL-1β and IL-18. Additionally, saffron extract enhanced SIRT1 expression, NRF2, and HMOX1 upregulation. These results suggest that NLRP3 inflammasome activation and the subsequent inflammatory response in the mice cortex are involved in the process of rmTBI. Saffron blocked the inflammatory response and relieved TBI by activating detoxifying genes and inhibiting NLRP3 activation. The effect of saffron on the NLRP3 inflammasome may be SIRT1 and NF-κB dependent in the rmTBI model. Thus, brain injury biomarkers will help in identifying a potential therapeutic target in treating TBI-induced neurodegenerative diseases.

Effects of manganese on microglia M1/M2 polarization and SIRT1-mediated transcription of STAT3-dependent genes in mouse

Overexposure to manganese (Mn) can lead to neurological diseases, characterized by behavioral and motor impairments. Microglia-mediated neuroinflammation is involved in the pathogenesis and progression of neurodegenerative diseases. Microglial M1 and M2 phenotypes play pro-inflammatory and anti-inflammatory roles, respectively, in response to microenvironmental disturbances. Silent information regulator (SIRT1) has been demonstrated to play an important role in the neuroinflammatory response by deacetylating various transcription factors, such as proliferator-activated receptor γ coactivator 1α (PGC-1α), nuclear factor kappa B (NF-κB), and signal transducer and activator of transcription 3 (STAT3). In addition, PGC-1α and STAT3 have been implicated in microglial polarization and inflammatory response. In this study, Mn exposure (50, 100, 200 μmol/kg) induced neuroinflammatory injury and interfered with microglial M1/M2 polarization in mice, as indicated by the upregulated expression of M1 polarization marker mRNA (IL-1β, IL-6, TNF-α, and iNOS), whereas changes in M2 polarization markers (IL-4, TGF-β, and Arg1) varied, with some increasing and some decreasing, in response to increasing Mn doses, which was consistent with the flow cytometry results used to detect the percentages of each microglial type. We found that Mn could downregulate SIRT1 expression and activate NF-κB signaling. Following mice in the 200 μmol/kg Mn treatment, STAT3 and PGC-1α levels in the nuclear fraction both significantly decreased, and the interaction between the proteins decreased, affecting the transcription of STAT3-mediated genes. These findings provide new insights regarding the role played by Mn neurotoxicity in the suppression of neuroinflammation through the regulation of microglial polarization.

Icariin ameliorate Alzheimer's disease by influencing SIRT1 and inhibiting Aβ cascade pathogenesis

Of all types of dementia, Alzheimer's disease is the type that has the highest proportion of cases and is the cause of substantial medical and economic burden. The mechanism of Alzheimer's disease is closely associated with the aggregation of amyloid-β protein and causes neurotoxicity and extracellular accumulation in the brain and to intracellular neurofibrillary tangles caused by tau protein hyperphosphorylation in the brain tissue. Previous studies have demonstrated that sirtuin1 downregulation is involved in the pathological mechanism of Alzheimer's disease. The decrease of sirtuin1 level would cause Alzheimer's disease by means of promoting the amyloidogenic pathway to generate amyloid-β species and thereby triggering amyloid-β cascade reaction, such as tau protein hyperphosphorylation, neuron autophagy, neuroinflammation, oxidative stress, and neuron apoptosis. Currently, there is no effective treatment for Alzheimer's disease, it is necessary to develop new treatment strategies. According to the theory of traditional Chinese medicine and based on the mechanism of the disease, tonifying the kidneys is one of the principles for the treatment of Alzheimer's disease and Epimedium is a well-known Chinese medicine for tonifying kidney. Therefore, investigating the influence of the components of Epimedium on the pathological characteristics of Alzheimer's disease may provide a reference for the treatment of Alzheimer's disease in the future. In this article, we summarise the effects and mechanism of icariin, the main ingredient extracted from Epimedium, in ameliorating Alzheimer's disease by regulating sirtuin1 to inhibit amyloid-β protein and improve other amyloid-β cascade pathogenesis.

The killifish visual system as an in vivo model to study brain aging and rejuvenation

Worldwide, people are getting older, and this prolonged lifespan unfortunately also results in an increased prevalence of age-related neurodegenerative diseases, contributing to a diminished life quality of elderly. Age-associated neuropathies typically include diseases leading to dementia (Alzheimer's and Parkinson's disease), as well as eye diseases such as glaucoma and age-related macular degeneration. Despite many research attempts aiming to unravel aging processes and their involvement in neurodegeneration and functional decline, achieving healthy brain aging remains a challenge. The African turquoise killifish (Nothobranchius furzeri) is the shortest-lived reported vertebrate that can be bred in captivity and displays many of the aging hallmarks that have been described for human aging, which makes it a very promising biogerontology model. As vision decline is an important hallmark of aging as well as a manifestation of many neurodegenerative diseases, we performed a comprehensive characterization of this fish's aging visual system. Our work reveals several aging hallmarks in the killifish retina and brain that eventually result in a diminished visual performance. Moreover, we found evidence for the occurrence of neurodegenerative events in the old killifish retina. Altogether, we introduce the visual system of the fast-aging killifish as a valuable model to understand the cellular and molecular mechanisms underlying aging in the vertebrate central nervous system. These findings put forward the killifish for target validation as well as drug discovery for rejuvenating or neuroprotective therapies ensuring healthy aging.

Two methoxy derivatives of resveratrol, 3,3',4,5'-tetramethoxy-trans-stilbene and 3,4',5-trimethoxy-trans-stilbene, suppress lipopolysaccharide-induced inflammation through inactivation of MAPK and NF-κB pathways in RAW 264.7 cells

Background

3,3′,4,5′-tetramethoxy-trans-stilbene (3,3′,4,5′-TMS) and 3,4′,5-trimethoxy-trans-stilbene (3,4′,5-TMS) are two methoxy derivatives of resveratrol. Previous researches have proved that resveratrol and its analogues have anti-inflammatory effect through suppressing mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways. This study aims to study whether 3,3′,4,5′-TMS and 3,4′,5-TMS alleviate inflammation and the underlying mechanism.

Methods

RAW 264.7 macrophage cells were treated with lipopolysaccharide (LPS) to induce inflammation and pretreated with 3,3′,4,5′-TMS or 3,4′,5-TMS. Cell viability was measured with the 3-(4,5)-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Nitric oxide (NO) release was detected by Griess reagent. The secretions of pro-inflammatory cytokines were assessed by ELISA kits. Protein expressions of signaling molecules were determined by Western blotting. Reactive oxygen species (ROS) production was detected by fluorescence staining and malondialdehyde (MDA) assay.

Results

3,3′,4,5′-TMS and 3,4′,5-TMS suppressed LPS-induced NO release and pro-inflammatory cytokines (IL-6 and TNF-α) secretions in a dose-dependent manner in RAW 264.7 cells. 3,3′,4,5′-TMS and 3,4′,5-TMS significantly down-regulated the LPS-induced expressions of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), and partially suppressed the activation of MAPK (phosphorylation of p38, JNK, ERK), and NF-κB (phosphorylation of IKKα/β, p65 and IκBα) signaling pathways; where phosphorylation of ERK and p65 was mildly but not significantly decreased by 3,3′,4,5′-TMS. LPS-induced NF-κB/p65 nuclear translocation was inhibited by both 3,3′,4,5′-TMS and 3,4′,5-TMS. Moreover, both resveratrol derivatives decreased the ROS levels.

Conclusions

3,3′,4,5′-TMS and 3,4′,5-TMS significantly suppress LPS-induced inflammation in RAW 264.7 cells through inhibition of MAPK and NF-κB signaling pathways and also provide anti-oxidative effect. This study reveals potential therapeutic applications of 3,3′,4,5′-TMS and 3,4′,5-TMS for inflammatory diseases.

The Role of Post-Translational Acetylation and Deacetylation of Signaling Proteins and Transcription Factors after Cerebral Ischemia: Facts and Hypotheses

Histone deacetylase (HDAC) and histone acetyltransferase (HAT) regulate transcription and the most important functions of cells by acetylating/deacetylating histones and non-histone proteins. These proteins are involved in cell survival and death, replication, DNA repair, the cell cycle, and cell responses to stress and aging. HDAC/HAT balance in cells affects gene expression and cell signaling. There are very few studies on the effects of stroke on non-histone protein acetylation/deacetylation in brain cells. HDAC inhibitors have been shown to be effective in protecting the brain from ischemic damage. However, the role of different HDAC isoforms in the survival and death of brain cells after stroke is still controversial. HAT/HDAC activity depends on the acetylation site and the acetylation/deacetylation of the main proteins (c-Myc, E2F1, p53, ERK1/2, Akt) considered in this review, that are involved in the regulation of cell fate decisions. Our review aims to analyze the possible role of the acetylation/deacetylation of transcription factors and signaling proteins involved in the regulation of survival and death in cerebral ischemia.

Protective role of SIRT1-mediated Sonic Hedgehog signaling pathway in the preeclampsia rat models

OBJECTIVE

To explore the role of silent information regulator 1 (SIRT1)-mediated Sonic Hedgehog (SHH) pathway in reduced uterine perfusion pressure (RUPP) model of preeclampsia (PE) in rats.

METHODS

The pregnant rats were divided into sham, RUPP, RUPP + rSIRT1 (recombinant SIRT1 protein), RUPP + rSHH (recombinant SHH protein), and RUPP + rSIRT1+ Cy (cyclopamine, an SHH pathway inhibitor) groups, followed by the determination of mean arterial pressure (MAP) and pregnancy outcome. The gene or protein expression was determined by enzyme-linked immunosorbent assay (ELISA), quantitative reverse transcription-polymerase chain reaction (qRT-PCR), or Western blotting.

RESULTS

RUPP rats showed increases MAP with the lower levels of vascular endothelial growth factor (VEGF) and nitrite and nitrate (NOx), as well as the higher levels of soluble FMS-like tyrosine kinase-1 (sFlt-1), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in maternal plasma, which was attenuated after rSIRT1 or rSHH treatment. Besides, the improvement in the pregnancy outcome was seen in the rats from the RUPP + rSIRT1/rSHH groups as compared with the RUPP group. However, the therapeutic effect of rSIRT1 was reversed by cyclopamine. Placenta tissues of RUPP rats manifested the down-regulations of SIRT1, Patched-1 (PTCH1), and GLI family zinc finger 2 (GLI2), which were up-regulated in the RUPP + rSIRT1 group.

CONCLUSION

SIRT1 was down-regulated while SHH pathway was inhibited in the placental tissue of PE rats. SIRT1 improved the blood pressure, angiogenic imbalance, inflammation, and pregnancy outcome in PE rats via SHH pathway, supporting its potential use for the treatment of PE.

Role of Polyphenols as Antioxidant Supplementation in Ischemic Stroke

Stroke is the second most common cause of death globally and the leading cause of death in China. The pathogenesis of cerebral ischemia injury is complex, and oxidative stress plays an important role in the fundamental pathologic progression of cerebral damage in ischemic stroke. Previous studies have preliminarily confirmed that oxidative stress should be a potential therapeutic target and antioxidant as a treatment strategy for ischemic stroke. Emerging experimental studies have demonstrated that polyphenols exert the antioxidant potential to play the neuroprotection role after ischemic stroke. This comprehensive review summarizes antioxidant effects of some polyphenols, which have the most inhibition effects on reactive oxygen species generation and oxidative stress after ischemic stroke.

Neuroinflammation in Alzheimer's Disease

Alzheimer’s disease (AD) is a neurodegenerative disease associated with human aging. Ten percent of individuals over 65 years have AD and its prevalence continues to rise with increasing age. There are currently no effective disease modifying treatments for AD, resulting in increasingly large socioeconomic and personal costs. Increasing age is associated with an increase in low-grade chronic inflammation (inflammaging) that may contribute to the neurodegenerative process in AD. Although the exact mechanisms remain unclear, aberrant elevation of reactive oxygen and nitrogen species (RONS) levels from several endogenous and exogenous processes in the brain may not only affect cell signaling, but also trigger cellular senescence, inflammation, and pyroptosis. Moreover, a compromised immune privilege of the brain that allows the infiltration of peripheral immune cells and infectious agents may play a role. Additionally, meta-inflammation as well as gut microbiota dysbiosis may drive the neuroinflammatory process. Considering that inflammatory/immune pathways are dysregulated in parallel with cognitive dysfunction in AD, elucidating the relationship between the central nervous system and the immune system may facilitate the development of a safe and effective therapy for AD. We discuss some current ideas on processes in inflammaging that appear to drive the neurodegenerative process in AD and summarize details on a few immunomodulatory strategies being developed to selectively target the detrimental aspects of neuroinflammation without affecting defense mechanisms against pathogens and tissue damage.

Formyl Peptide Receptor (FPR)1 Modulation by Resveratrol in an LPS-Induced Neuroinflammatory Animal Model

Among therapeutic approaches that have been investigated, targeting of receptors implicated in managing neuroinflammation has been described. One such family of receptors comprises the formyl peptide receptors (FPRs) whose ligands could play a role in host defense. The murine FPR gene family includes at least six members while in humans there are only three. The two most important members are the Fpr1 and Fpr2. Fpr1encodes murine FPR1, which is considered the murine orthologue of human FPR. Resveratrol, a non-flavonoid polyphenol rich in red wine and grapes, apart from its beneficial health effects and anti-inflammatory properties, has been reported to reduce neuroinflammation in different neurodegenerative disease models. Resveratrol anti-inflammatory responses involve the activation of the protein deacetylase sirtuin 1 (SIRT1) gene. In this work we have investigated in an LPS-based murine model of neuroinflammation the role of FPR1, examining not only if this receptor undergoes a reduction of its expression during neuroinflammation, but also whether treatment with resveratrol was able to modulate its expression leading to an amelioration of neuroinflammatory picture in a murine model of neuroinflammation. Results of this work showed that FPR1 together with SIRT1 resulted upregulated by resveratrol treatment and that this increase is associated with an amelioration of the neuroinflammatory picture, as demonstrated by the induction of IL-10 and IL1-RA expression and the downregulation of proinflammatory mediators, such as TNF-α and IL-1β. The expression and the modulation of FPR1 by resveratrol may be evaluated in order to propose a novel anti-inflammatory and pro-resolving therapeutic approach for the reduction of the detrimental effects associated with neuro-inflammation based neurodegenerative diseases and also as a promising strategy to promote human health by a diet rich in antioxidative bioactive compounds.

Research progress on the potential delaying skin aging effect and mechanism of tea for oral and external use

Skin aging is characterized by the gradual loss of elasticity, the formation of wrinkles and various color spots, the degradation of extracellular matrix proteins, and the structural changes of the dermis. With the increasingly prominent problems of environmental pollution, social pressure, ozone layer thinning and food safety, skin problems have become more and more complex. The skin can reflect the overall health of the body. Skincare products for external use alone cannot fundamentally solve skin problems; it needs to improve the overall health of the body. Based on the literature review in recent 20 years, this paper systematically reviewed the potential delaying effect of tea and its active ingredients on skin aging by oral and external use. Tea is the second-largest health drink after water. It is rich in tea polyphenols, l-theanine, tea pigments, caffeine, tea saponins, tea polysaccharides and other secondary metabolites. Tea and its active substances have whitening, nourishing, anti-wrinkle, removing spots and other skincare effects. Its mechanism of action is ultraviolet absorption, antioxidant, anti-inflammatory, inhibition of extracellular matrix aging, inhibiting the accumulation of melanin and toxic oxidation products, balancing intestinal and skin microorganisms, and improving mood and sleep, among other effects. At present, tea elements skincare products are deeply loved by consumers. This paper provides a scientific theoretical basis for tea-assisted beauty and the high-end application of tea in skincare products.

The Pleiotropic Function of Human Sirtuins as Modulators of Metabolic Pathways and Viral Infections

Sirtuins (SIRTs) are nicotinamide adenine dinucleotide-dependent histone deacetylases that incorporate complex functions in the mechanisms of cell physiology. Mammals have seven distinct members of the SIRT family (SIRT1-7), which play an important role in a well-maintained network of metabolic pathways that control and adapt the cell to the environment, energy availability and cellular stress. Until recently, very few studies investigated the role of SIRTs in modulating viral infection and progeny. Recent studies have demonstrated that SIRT1 and SIRT2 are promising antiviral targets because of their specific connection to numerous metabolic and regulatory processes affected during infection. In the present review, we summarize some of the recent progress in SIRTs biochemistry and their emerging function as antiviral targets. We also discuss the potential of natural polyphenol-based SIRT modulators to control their functional roles in several diseases including viral infections.