scholarly journals Natural Compounds and Aging: Between Autophagy and Inflammasome

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Shih-Yi Chuang ◽  
Chih-Hung Lin ◽  
Jia-You Fang

Aging, a natural physiological process, is characterized by a progressive loss of physiological integrity. Loss of cellular homeostasis in the aging process results from different sources, including changes in genes, cell imbalance, and dysregulation of the host-defense systems. Innate immunity dysfunctions during aging are connected with several human pathologies, including metabolic disorders and cardiovascular diseases. Recent studies have clearly indicated that the decline in autophagic capacity that accompanies aging results in the accumulation of dysfunctional mitochondria, reactive oxygen species (ROS) production, and further process dysfunction of the NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome activation in the macrophages, which produce the proinflammatory cytokines. These factors impair cellular housekeeping and expose cells to higher risk in many age-related diseases, such as atherosclerosis and type 2 diabetes. In this review, we investigated the relationship between dysregulation of the inflammasome activation and perturbed autophagy with aging as well as the possible molecular mechanisms. We also summarized the natural compounds from food intake, which have potential to reduce the inflammasome activation and enhance autophagy and can further improve the age-related diseases discussed in this paper.

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Elisa Benetti ◽  
Fausto Chiazza ◽  
Nimesh S. A. Patel ◽  
Massimo Collino

The combination of obesity and type 2 diabetes is a serious health problem, which is projected to afflict 300 million people worldwide by 2020. Both clinical and translational laboratory studies have demonstrated that chronic inflammation is associated with obesity and obesity-related conditions such as insulin resistance. However, the precise etiopathogenetic mechanisms linking obesity to diabetes remain to be elucidated, and the pathways that mediate this phenomenon are not fully characterized. One of the most recently identified signaling pathways, whose activation seems to affect many metabolic disorders, is the “inflammasome,” a multiprotein complex composed of NLRP3 (nucleotide-binding domain and leucine-rich repeat protein 3), ASC (apoptosis-associated speck-like protein containing a CARD), and procaspase-1. NLRP3 inflammasome activation leads to the processing and secretion of the proinflammatory cytokines interleukin- (IL-) 1βand IL-18. The goal of this paper is to review new insights on the effects of the NLRP3 inflammasome activation in the complex mechanisms of crosstalk between different organs, for a better understanding of the role of chronic inflammation in metabolic disease pathogenesis. We will provide here a perspective on the current research on NLRP3 inflammasome, which may represent an innovative therapeutic target to reverse the detrimental metabolic consequences of the metabolic inflammation.


2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Ana L. Santos ◽  
Ariel B. Lindner

Aging is characterized by the progressive decline of biochemical and physiological function in an individual. Consequently, aging is a major risk factor for diseases like cancer, obesity, and type 2 diabetes. The cellular and molecular mechanisms of aging are not well understood, nor is the relationship between aging and the onset of diseases. One of the hallmarks of aging is a decrease in cellular proteome homeostasis, allowing abnormal proteins to accumulate. This phenomenon is observed in both eukaryotes and prokaryotes, suggesting that the underlying molecular processes are evolutionarily conserved. Similar protein aggregation occurs in the pathogenesis of diseases like Alzheimer’s and Parkinson’s. Further, protein posttranslational modifications (PTMs), either spontaneous or physiological/pathological, are emerging as important markers of aging and aging-related diseases, though clear causality has not yet been firmly established. This review presents an overview of the interplay of PTMs in aging-associated molecular processes in eukaryotic aging models. Understanding PTM roles in aging could facilitate targeted therapies or interventions for age-related diseases. In addition, the study of PTMs in prokaryotes is highlighted, revealing the potential of simple prokaryotic models to uncover complex aging-associated molecular processes in the emerging field of microbiogerontology.


2021 ◽  
Vol 22 (7) ◽  
pp. 3566
Author(s):  
Chae Bin Lee ◽  
Soon Uk Chae ◽  
Seong Jun Jo ◽  
Ui Min Jerng ◽  
Soo Kyung Bae

Metformin is the first-line pharmacotherapy for treating type 2 diabetes mellitus (T2DM); however, its mechanism of modulating glucose metabolism is elusive. Recent advances have identified the gut as a potential target of metformin. As patients with metabolic disorders exhibit dysbiosis, the gut microbiome has garnered interest as a potential target for metabolic disease. Henceforth, studies have focused on unraveling the relationship of metabolic disorders with the human gut microbiome. According to various metagenome studies, gut dysbiosis is evident in T2DM patients. Besides this, alterations in the gut microbiome were also observed in the metformin-treated T2DM patients compared to the non-treated T2DM patients. Thus, several studies on rodents have suggested potential mechanisms interacting with the gut microbiome, including regulation of glucose metabolism, an increase in short-chain fatty acids, strengthening intestinal permeability against lipopolysaccharides, modulating the immune response, and interaction with bile acids. Furthermore, human studies have demonstrated evidence substantiating the hypotheses based on rodent studies. This review discusses the current knowledge of how metformin modulates T2DM with respect to the gut microbiome and discusses the prospect of harnessing this mechanism in treating T2DM.


Antioxidants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 25
Author(s):  
Lara Macchioni ◽  
Davide Chiasserini ◽  
Letizia Mezzasoma ◽  
Magdalena Davidescu ◽  
Pier Luigi Orvietani ◽  
...  

Age-related retinal degenerations, including age-related macular degeneration (AMD), are caused by the loss of retinal pigmented epithelial (RPE) cells and photoreceptors. The pathogenesis of AMD, deeply linked to the aging process, also involves oxidative stress and inflammatory responses. However, the molecular mechanisms contributing to the shift from healthy aging to AMD are still poorly understood. Since RPE cells in the retina are chronically exposed to a pro-oxidant microenvironment throughout life, we simulated in vivo conditions by growing ARPE-19 cells in the presence of 10 μM H2O2 for several passages. This long-term oxidative insult induced senescence in ARPE-19 cells without affecting cell proliferation. Global proteomic analysis revealed a dysregulated expression in proteins involved in antioxidant response, mitochondrial homeostasis, and extracellular matrix organization. The analyses of mitochondrial functionality showed increased mitochondrial biogenesis and ATP generation and improved response to oxidative stress. The latter, however, was linked to nuclear factor-κB (NF-κB) rather than nuclear factor erythroid 2–related factor 2 (Nrf2) activation. NF-κB hyperactivation also resulted in increased pro-inflammatory cytokines expression and inflammasome activation. Moreover, in response to additional pro-inflammatory insults, senescent ARPE-19 cells underwent an exaggerated inflammatory reaction. Our results indicate senescence as an important link between chronic oxidative insult and detrimental chronic inflammation, with possible future repercussions for therapeutic interventions.


2021 ◽  
Vol 22 (2) ◽  
pp. 803
Author(s):  
Giuseppina Emanuela Grieco ◽  
Noemi Brusco ◽  
Giada Licata ◽  
Daniela Fignani ◽  
Caterina Formichi ◽  
...  

Diabetes mellitus is a group of heterogeneous metabolic disorders characterized by chronic hyperglycaemia mainly due to pancreatic β cell death and/or dysfunction, caused by several types of stress such as glucotoxicity, lipotoxicity and inflammation. Different patho-physiological mechanisms driving β cell response to these stresses are tightly regulated by microRNAs (miRNAs), a class of negative regulators of gene expression, involved in pathogenic mechanisms occurring in diabetes and in its complications. In this review, we aim to shed light on the most important miRNAs regulating the maintenance and the robustness of β cell identity, as well as on those miRNAs involved in the pathogenesis of the two main forms of diabetes mellitus, i.e., type 1 and type 2 diabetes. Additionally, we acknowledge that the understanding of miRNAs-regulated molecular mechanisms is fundamental in order to develop specific and effective strategies based on miRNAs as therapeutic targets, employing innovative molecules.


2021 ◽  
Author(s):  
Meihuan Zhao ◽  
Yuan Dai ◽  
Ping Li ◽  
Jie wang ◽  
Tengyun Ma ◽  
...  

Zanthoxylum bungeanum Maxim (Rutaceae), a homologous of medicine and foodstuff, has previously been demonstrated the potential prevention of age-related cognitive dysfunction. However, the mechanisms and material basis remain elusively understood....


2018 ◽  
Vol 92 (19) ◽  
Author(s):  
Takayuki Komatsu ◽  
Yukie Tanaka ◽  
Yoshinori Kitagawa ◽  
Naoki Koide ◽  
Yoshikazu Naiki ◽  
...  

ABSTRACT Inflammasomes play a key role in host innate immune responses to viral infection by caspase-1 (Casp-1) activation to facilitate interleukin-1β (IL-1β) secretion, which contributes to the host antiviral defense. The NLRP3 inflammasome consists of the cytoplasmic sensor molecule NLRP3, adaptor protein ASC, and effector protein pro-caspase-1 (pro-Casp-1). NLRP3 and ASC promote pro-Casp-1 cleavage, leading to IL-1β maturation and secretion. However, as a countermeasure, viral pathogens have evolved virulence factors to antagonize inflammasome pathways. Here we report that V gene knockout Sendai virus [SeV V(−)] induced markedly greater amounts of IL-1β than wild-type SeV in infected THP1 macrophages. Deficiency of NLRP3 in cells inhibited SeV V(−)-induced IL-1β secretion, indicating an essential role for NLRP3 in SeV V(−)-induced IL-1β activation. Moreover, SeV V protein inhibited the assembly of NLRP3 inflammasomes, including NLRP3-dependent ASC oligomerization, NLRP3-ASC association, NLRP3 self-oligomerization, and intermolecular interactions between NLRP3 molecules. Furthermore, a high correlation between the NLRP3-binding capacity of V protein and the ability to block inflammasome complex assembly was observed. Therefore, SeV V protein likely inhibits NLRP3 self-oligomerization by interacting with NLRP3 and inhibiting subsequent recruitment of ASC to block NLRP3-dependent ASC oligomerization, in turn blocking full activation of the NLRP3 inflammasome and thus blocking IL-1β secretion. Notably, the inhibitory action of SeV V protein on NLRP3 inflammasome activation is shared by other paramyxovirus V proteins, such as Nipah virus and human parainfluenza virus type 2. We thus reveal a mechanism by which paramyxovirus inhibits inflammatory responses by inhibiting NLRP3 inflammasome complex assembly and IL-1β activation. IMPORTANCE The present study demonstrates that the V protein of SeV, Nipah virus, and human parainfluenza virus type 2 interacts with NLRP3 to inhibit NLRP3 inflammasome activation, potentially suggesting a novel strategy by which viruses evade the host innate immune response. As all members of the Paramyxovirinae subfamily carry similar V genes, this new finding may also lead to identification of novel therapeutic targets for paramyxovirus infection and related diseases.


2021 ◽  
Vol 22 (21) ◽  
pp. 11629
Author(s):  
Jorge Gutiérrez-Cuevas ◽  
Arturo Santos ◽  
Juan Armendariz-Borunda

Obesity is now a worldwide epidemic ensuing an increase in comorbidities’ prevalence, such as insulin resistance, type 2 diabetes (T2D), metabolic dysfunction-associated fatty liver disease (MAFLD), nonalcoholic steatohepatitis (NASH), hypertension, cardiovascular disease (CVD), autoimmune diseases, and some cancers, CVD being one of the main causes of death in the world. Several studies provide evidence for an association between MAFLD and atherosclerosis and cardio-metabolic disorders, including CVDs such as coronary heart disease and stroke. Therefore, the combination of MAFLD/NASH is associated with vascular risk and CVD progression, but the underlying mechanisms linking MAFLD/NASH and CVD are still under investigation. Several underlying mechanisms may probably be involved, including hepatic/systemic insulin resistance, atherogenic dyslipidemia, hypertension, as well as pro-atherogenic, pro-coagulant, and pro-inflammatory mediators released from the steatotic/inflamed liver. MAFLD is strongly associated with insulin resistance, which is involved in its pathogenesis and progression to NASH. Insulin resistance is a major cardiovascular risk factor in subjects without diabetes. However, T2D has been considered the most common link between MAFLD/NASH and CVD. This review summarizes the evidence linking obesity with MAFLD, NASH, and CVD, considering the pathophysiological molecular mechanisms involved in these diseases. We also discuss the association of MAFLD and NASH with the development and progression of CVD, including structural and functional cardiac alterations, and pharmacological strategies to treat MAFLD/NASH and cardiovascular prevention.


2020 ◽  
Author(s):  
Daniel Ahmed ◽  
Martin Stattin ◽  
Anna-Maria Haas ◽  
Alexandra Graf ◽  
Katharina Krepler ◽  
...  

Abstract Background: To assess the relationship between drusen characteristics and type 2 macular neovascularization (MNV) in age-related macular degeneration (AMD)Methods: Retrospective data analysis of eyes previously diagnosed with neovascular AMD in a tertiary eye care center (Medical Retina Unit, Rudolf Foundation Hospital, Vienna, Austria) between June 2008 and December 2017. Drusen subtypes, fibrosis, atrophy and subfoveal choroidal thickness (SFCT) of both eyes in patients with type 2 MNV lesions were categorized based on multimodal imaging.Results: Type 2 MNV was diagnosed in 27 (3.2%) of 835 eyes (749 patients). Drusen characteristics in type 2 MNV were observed as followed: drusen < 63 mm in 2 eyes (7.4%), drusen ≥ 63 mm in 10 eyes (37%), subretinal drusenoid deposits (SDD) in 8 eyes (29.6%), cuticular drusen in 2 eye (7.4%) and no drusen were evident in 10 eyes (37%). Drusen distribution in 23 fellow eyes was detected as followed: drusen < 63 mm in 2 eyes (8.7%), drusen ≥ 63 mm in 9 eyes (39.1%), SDD in 5 eyes (21.7%), cuticular drusen in 1 eye (4.3%) and no drusen were evident in 9 eyes (39.1%). Mean SFCT was 140 ± 49 mm in affected eyes and 152 ± 41 mm in the fellow eyes. Patients with drusen or SDD were significantly younger (mean 70.88 ± 6.85, p=0.04) than patients without deposits (mean 77.40 ± 5.74). Conclusions: Type 2 MNV remains a rare entity in AMD. It was frequently seen in the absence ofdrusen, a hallmark of AMD. These findings contribute to the heterogeneity of phenotypes related to pure type 2 lesions.


2020 ◽  
Vol 21 (11) ◽  
pp. 3740 ◽  
Author(s):  
Claudia Espinosa-Garcia ◽  
Fahim Atif ◽  
Seema Yousuf ◽  
Iqbal Sayeed ◽  
Gretchen N. Neigh ◽  
...  

NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome inhibition and autophagy induction attenuate inflammation and improve outcome in rodent models of cerebral ischemia. However, the impact of chronic stress on NLRP3 inflammasome and autophagic response to ischemia remains unknown. Progesterone (PROG), a neuroprotective steroid, shows promise in reducing excessive inflammation associated with poor outcome in ischemic brain injury patients with comorbid conditions, including elevated stress. Stress primes microglia, mainly by the release of alarmins such as high-mobility group box-1 (HMGB1). HMGB1 activates the NLRP3 inflammasome, resulting in pro-inflammatory interleukin (IL)-1β production. In experiment 1, adult male Sprague-Dawley rats were exposed to social defeat stress for 8 days and then subjected to global ischemia by the 4-vessel occlusion model, a clinically relevant brain injury associated with cardiac arrest. PROG was administered 2 and 6 h after occlusion and then daily for 7 days. Animals were killed at 7 or 14 days post-ischemia. Here, we show that stress and global ischemia exert a synergistic effect in HMGB1 release, resulting in exacerbation of NLRP3 inflammasome activation and autophagy impairment in the hippocampus of ischemic animals. In experiment 2, an in vitro inflammasome assay, primary microglia isolated from neonatal brain tissue, were primed with lipopolysaccharide (LPS) and stimulated with adenosine triphosphate (ATP), displaying impaired autophagy and increased IL-1β production. In experiment 3, hippocampal microglia isolated from stressed and unstressed animals, were stimulated ex vivo with LPS, exhibiting similar changes than primary microglia. Treatment with PROG reduced HMGB1 release and NLRP3 inflammasome activation, and enhanced autophagy in stressed and unstressed ischemic animals. Pre-treatment with an autophagy inhibitor blocked Progesterone’s (PROG’s) beneficial effects in microglia. Our data suggest that modulation of microglial priming is one of the molecular mechanisms by which PROG ameliorates ischemic brain injury under stressful conditions.


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