Implications of Necroptosis for Cardiovascular Diseases. Curr Med Sci. 2019;39:513-522. [PMID: 31346984 DOI: 10.1007/s11596-019-2067-6]

PM2.5-mediated cardiovascular disease in aging: Cardiometabolic risks, molecular mechanisms and potential interventions

Air pollution, particularly fine particulate matter (PM2.5) with <2.5 μm in diameter, is a major public health concern. Studies have consistently linked PM2.5 exposure to a heightened risk of cardiovascular diseases (CVDs) such as ischemic heart disease (IHD), heart failure (HF), and cardiac arrhythmias. Notably, individuals with pre-existing age-related cardiometabolic conditions appear more susceptible. However, the specific impact of PM2.5 on CVDs susceptibility in older adults remains unclear. Therefore, this review addresses this gap by discussing the factors that make the elderly more vulnerable to PM2.5-induced CVDs. Accordingly, we focused on physiological aging, increased susceptibility, cardiometabolic risk factors, CVDs, and biological mechanisms. This review concludes by examining potential interventions to reduce exposure and the adverse health effects of PM2.5 in the elderly population. The latter includes dietary modifications, medications, and exploration of the potential benefits of supplements. By comprehensively analyzing these factors, this review aims to provide a deeper understanding of the detrimental effects of PM2.5 on cardiovascular health in older adults. This knowledge can inform future research and guide strategies to protect vulnerable populations from the adverse effects of air pollution.

Recognition of necroptosis: From molecular mechanisms to detection methods

Necroptosis is a crucial modality of programmed cell death characterized by distinct morphological and biochemical hallmarks, including cell membrane rupture, organelle swelling, cytoplasmic and nuclear disintegration, cellular contents leakage, and release of damage-associated molecular patterns (DAMPs), accompanied by the inflammatory responses. Studies have shown that necroptosis is involved in the etiology and evolution of a variety of pathologies including organ damage, inflammation disorders, and cancer. Despite its significance, the field of necroptosis research grapples with the challenge of non-standardized detection methodologies. In this review, we introduce the fundamental concepts and molecular mechanisms of necroptosis and critically appraise the principles, merits, and inherent limitations of current detection technologies. This endeavor seeks to establish a methodological framework for necroptosis detection, thereby propelling deeper insights into the research of cell necroptosis.

Cell death in atherosclerosis

A complex and evolutionary process that involves the buildup of lipids in the arterial wall and the invasion of inflammatory cells results in atherosclerosis. Cell death is a fundamental biological process that is essential to the growth and dynamic equilibrium of all living things. Serious cell damage can cause a number of metabolic processes to stop, cell structure to be destroyed, or other irreversible changes that result in cell death. It is important to note that studies have shown that the two types of programmed cell death, apoptosis and autophagy, influence the onset and progression of atherosclerosis by controlling these cells. This could serve as a foundation for the creation of fresh atherosclerosis prevention and treatment strategies. Therefore, in this review, we summarized the molecular mechanisms of cell death, including apoptosis, pyroptosis, autophagy, necroptosis, ferroptosis and necrosis, and discussed their effects on endothelial cells, vascular smooth muscle cells and macrophages in the process of atherosclerosis, so as to provide reference for the next step to reveal the mechanism of atherosclerosis.

MSC exosomes attenuate sterile inflammation and necroptosis associated with TAK1-pJNK-NFKB mediated cardiomyopathy in diabetic ApoE KO mice

Introduction

Diabetes is a debilitating disease that leads to complications like cardiac dysfunction and heart failure. In this study, we investigated the pathophysiology of diabetes-induced cardiac dysfunction in mice with dyslipidemia. We hypothesize diabetes in ApoE knockout (ApoE-/-) mice induces cardiac dysfunction by increasing inflammation and necroptosis.

Methods

ApoE-/- mice were divided into experimental groups: Control, Streptozotocin (STZ), STZ + MSC-Exo (mesenchymal stem cell-derived exosomes), and STZ+MEF-Exo (Mouse embryonic fibroblast derived exosomes). At Day 42, we assessed cardiac function, collected blood and heart tissues. Heart tissue samples were analyzed for inflammation, necroptosis, signaling mechanism, hypertrophy and adverse structural remodeling using histology, immunohistochemistry, western blotting, RT-PCR, cytokine array and TF array.

Results and Discussion

STZ treated ApoE-/- mice developed diabetes, with significantly (p<0.05) increased blood glucose and body weight loss. These mice developed cardiac dysfunction with significantly (p<0.05) increased left ventricular internal diameter end diastole and end systole, and decreased ejection fraction, and fractional shortening. We found significant (p<0.05) increased expression of inflammatory cytokines TNF- a, IL-6, IL-1a, IL-33 and decreased IL-10 expression. Diabetic mice also exhibited significantly (p<0.05) increased necroptosis marker expression and infiltration of inflammatory monocytes and macrophages. MSC-Exos treated mice showed recovery of diabetes associated pathologies with significantly reduced blood glucose, recovered body weight, increased IL-10 secretion and M2 polarized macrophages in the heart. These mice showed reduced TAK1-pJNK-NFKB inflammation associated expression and improved cardiac function with significantly reduced cardiac hypertrophy and fibrosis compared to diabetic mice. Treatment with MEF-Exos did not play a significant role in attenuating diabetes-induced cardiomyopathy as these treatment mice presented with cardiac dysfunction and underlying pathologies observed in STZ mice.

Conclusion

Thus, we conclude that cardiac dysfunction develops in diabetic ApoE-/- mice, arising from inflammation, necroptosis, and adverse tissue remodeling, which is ameliorated by MSC-Exos, a potential therapeutic for diabetes-induced cardiomyopathy.

Role of RIPK3‑CaMKII‑mPTP signaling pathway‑mediated necroptosis in cardiovascular diseases (Review)

Necroptosis, which is distinct from apoptosis and necrosis, serves a crucial role in ontogeny and the maintenance of homeostasis. In the last decade, it has been demonstrated that the pathogenesis of cardiovascular diseases is also linked to necroptosis. Receptor interaction protein kinase (RIPK) 1, RIPK3 and mixed lineage kinase domain‑like protein serve vital roles in necroptosis. In addition to the aforementioned necroptosis‑related components, calcium/calmodulin‑dependent protein kinase II (CaMKII) has been identified as a novel substrate for RIPK3 that promotes the opening of the mitochondrial permeability transition pore (mPTP), and thus, mediates necroptosis of myocardial cells through the RIPK3‑CaMKII‑mPTP signaling pathway. The present review provides an overview of the current knowledge of the RIPK3‑CaMKII‑mPTP‑mediated necroptosis signaling pathway in cardiovascular diseases, focusing on the role of the RIPK3‑CaMKII‑mPTP signaling pathway in acute myocardial infarction, ischemia‑reperfusion injury, heart failure, abdominal aortic aneurysm, atherosclerosis, diabetic cardiomyopathy, hypertrophic cardiomyopathy, atrial fibrillation, and the cardiotoxicity associated with antitumor drugs and other chemicals. Finally, the present review discusses the research status of drugs targeting the RIPK3‑CaMKII‑mPTP signaling pathway.

Construction of a Necroptosis-Related miRNA Signature for Predicting the Prognosis of Patients With Hepatocellular Carcinoma

Background: Many miRNAs have been demonstrated to be associated with the prognosis of hepatocellular carcinoma (HCC). However, how to combine necroptosis-related miRNAs to achieve the best predictive effect in estimating HCC patient survival has not been explored.

Methods: The mRNA and miRNA expression profile were downloaded from a public database (TCGA-LIHC cohort). Necroptosis-related genes were obtained from previous references, and necroptosis-related miRNAs were identified using Pearson analysis. Subsequently, differential expression miRNAs (DEms) were identified in HCC and paracancer normal samples based on necroptosis-related miRNA expression. The whole set with HCC was randomized into a training set and testing set (1:1). LASSO-Cox regression analysis was used to construct an miRNA signature. Multiple statistical methods were used to validate the clinical benefit of signature in HCC patients, including receiver operator characteristic (ROC) curves, Kaplan–Meier survival analyses, and decision curve analysis (DCA). The downstream target genes of miRNAs were obtained from different online tools, and the potential pathways involved in miRNAs were explored. Finally, we conducted RT-qPCR in SK-HEP-1, THLE-3, and HUH-7 cell lines for miRNAs involved in the signature.

Results: The results showed that a total of eight specific necroptosis-related miRNAs were screened between HCC and adjacent tissues in the training set. Subsequently, based on the aforementioned miRNAs, 5-miRNA signature (miR-139-5p, hsa-miR-326, miR-10b-5p, miR-500a-3p, and miR-592) was generated by LASSO-Cox regression analysis. Multivariate Cox regression analysis showed that the risk scores were independent prognostic indicators in each set. The area under curves (AUCs) of 1 year, 3 years, 5 years, and 7 years were high in each set (AUC >0.7). DCA analysis also revealed that the risk score had a potential benefit than other clinical characteristics. Meanwhile, survival analysis showed that the high-risk group showed low survival probabilities. Moreover, the results of enrichment analysis showed that specific miRNAs were mainly enriched in the cAMP signaling pathway and TNF signaling pathway. Finally, the results of RT-qPCR were consistent with the prediction results in public databases.

Conclusion: Our study establishes a robust tool based on 5-necroptosis-related miRNAs for the prognostic management of HCC patients.

Atherosclerosis: Pathogenesis and Key Cellular Processes, Current and Emerging Therapies, Key Challenges, and Future Research Directions

Atherosclerosis is the principal cause of cardiovascular disease that continues to be a substantial drain on healthcare systems, being responsible for about 31% of all global deaths. Atherogenesis is influenced by a range of factors, including oxidative stress, inflammation, hypertension, and hyperlipidemia, and is ultimately driven by the accumulation of low-density lipoprotein cholesterol within the arterial wall of medium and large arteries. Lipoprotein accumulation stimulates the infiltration of immune cells (such as monocytes/macrophages and T-lymphocytes), some of which take up the lipoprotein, leading to the formation of lipid-laden foam cells. Foam cell death results in increased accumulation of dead cells, cellular debris and extracellular cholesterol, forming a lipid-rich necrotic core. Vascular smooth muscle cells from the arterial media also migrate into the intima layer and proliferate, taking up the available lipids to become foam cells and producing extracellular matrix proteins such as collagen and elastin. Plaque progression is characterized by the formation of a fibrous cap composed of extracellular matrix proteins and smooth muscle cells, which acts to stabilize the atherosclerotic plaque. Degradation, thinning, and subsequent rupture of the fibrous cap leads to lumen-occlusive atherothrombosis, most commonly resulting in heart attack or stroke. This chapter describes the pathogenesis of atherosclerosis, current and emerging therapies, key challenges, and future directions of research.

Preliminary evidence for the presence of multiple forms of cell death in diabetes cardiomyopathy

Diabetic mellitus (DM) is a common degenerative chronic metabolic disease often accompanied by severe cardiovascular complications (DCCs) as major causes of death in diabetic patients with diabetic cardiomyopathy (DCM) as the most common DCC. The metabolic disturbance in DCM generates the conditions/substrates and inducers/triggers and activates the signaling molecules and death executioners leading to cardiomyocyte death which accelerates the development of DCM and the degeneration of DCM to heart failure. Various forms of programmed active cell death including apoptosis, pyroptosis, autophagic cell death, autosis, necroptosis, ferroptosis and entosis have been identified and characterized in many types of cardiac disease. Evidence has also been obtained for the presence of multiple forms of cell death in DCM. Most importantly, published animal experiments have demonstrated that suppression of cardiomyocyte death of any forms yields tremendous protective effects on DCM. Herein, we provide the most updated data on the subject of cell death in DCM, critical analysis of published results focusing on the pathophysiological roles of cell death, and pertinent perspectives of future studies.

The type-1 ribosome-inactivating protein OsRIP1 triggers caspase-independent apoptotic-like death in HeLa cells

Ribosome-inactivating proteins (RIPs) are capable of removing a specific adenine from 28S ribosomal RNA, thus inhibiting protein biosynthesis in an irreversible manner. In this study, recombinant OsRIP1, a type 1 RIP from rice (Oryza sativa L.), was investigated for its anti-proliferative properties. Human cervical cancer HeLa cells were incubated in the presence of OsRIP1 for 24-72 h. OsRIP1 treatment yielded an anti-proliferation response of the HeLa cells and resulted in apoptotic-like blebbing of the plasma membrane without causing DNA fragmentation. OsRIP1 labeled with FITC accumulated at the cell surface. Pull-down assays identified ASPP1 (Apoptosis-Stimulating Protein of p53 1) and IFITM3 (interferon-induced transmembrane protein 3) as potential interaction partners for OsRIP1. Transcript levels for several critical genes related to different signaling pathways were quantified by RT-qPCR. OsRIP1 provoked HeLa cells to undergo caspase-independent cell death, associated with a significant transcriptional upregulation of the apoptotic gene PUMA, interferon regulatory factor 1 (IRF1) and the autophagy-related marker LC3. No changes in caspase activities were observed. Together, these data suggest that apoptotic-like events were involved in OsRIP1-driven caspase-independent cell death that might trigger the IRF1 signaling pathway and LC3-mediated autophagy.

A systematic summary of survival and death signalling during the life of hair follicle stem cells

Hair follicle stem cells (HFSCs) are among the most widely available resources and most frequently approved model systems used for studying adult stem cells. HFSCs are particularly useful because of their self-renewal and differentiation properties. Additionally, the cyclic growth of hair follicles is driven by HFSCs. There are high expectations for the use of HFSCs as favourable systems for studying the molecular mechanisms that contribute to HFSC identification and can be applied to hair loss therapy, such as the activation or regeneration of hair follicles, and to the generation of hair using a tissue-engineering strategy. A variety of molecules are involved in the networks that critically regulate the fate of HFSCs, such as factors in hair follicle growth and development (in the Wnt pathway, Sonic hedgehog pathway, Notch pathway, and BMP pathway), and that suppress apoptotic cues (the apoptosis pathway). Here, we review the life cycle, biomarkers and functions of HFSCs, concluding with a summary of the signalling pathways involved in HFSC fate for promoting better understanding of the pathophysiological changes in the HFSC niche. Importantly, we highlight the potential mechanisms underlying the therapeutic targets involved in pathways associated with the treatment of hair loss and other disorders of skin and hair, including alopecia, skin cancer, skin inflammation, and skin wound healing.

The Role of HSP90α in Methamphetamine/Hyperthermia-Induced Necroptosis in Rat Striatal Neurons

Methamphetamine (METH) is one of the most widely abused synthetic drugs in the world. The users generally present hyperthermia (HT) and psychiatric symptoms. However, the mechanisms involved in METH/HT-induced neurotoxicity remain elusive. Here, we investigated the role of heat shock protein 90 alpha (HSP90α) in METH/HT (39.5°C)-induced necroptosis in rat striatal neurons and an in vivo rat model. METH treatment increased core body temperature and up-regulated LDH activity and the molecular expression of canonical necroptotic factors in the striatum of rats. METH and HT can induce necroptosis in primary cultures of striatal neurons. The expression of HSP90α increased following METH/HT injuries. The specific inhibitor of HSP90α, geldanamycin (GA), and HSP90α shRNA attenuated the METH/HT-induced upregulation of receptor-interacting protein 3 (RIP3), phosphorylated RIP3, mixed lineage kinase domain-like protein (MLKL), and phosphorylated MLKL. The inhibition of HSP90α protected the primary cultures of striatal neurons from METH/HT-induced necroptosis. In conclusion, HSP90α plays an important role in METH/HT-induced neuronal necroptosis and the HSP90α-RIP3 pathway is a promising therapeutic target for METH/HT-induced neurotoxicity in the striatum.

RhoA Signaling in Immune Cell Response and Cardiac Disease

Chronic inflammation, the activation of immune cells and their cross-talk with cardiomyocytes in the pathogenesis and progression of heart diseases has long been overlooked. However, with the latest research developments, it is increasingly accepted that a vicious cycle exists where cardiomyocytes release cardiocrine signaling molecules that spiral down to immune cell activation and chronic state of low-level inflammation. For example, cardiocrine molecules released from injured or stressed cardiomyocytes can stimulate macrophages, dendritic cells, neutrophils and even T-cells, which then subsequently increase cardiac inflammation by co-stimulation and positive feedback loops. One of the key proteins involved in stress-mediated cardiomyocyte signal transduction is a small GTPase RhoA. Importantly, the regulation of RhoA activation is critical for effective immune cell response and is being considered as one of the potential therapeutic targets in many immune-cell-mediated inflammatory diseases. In this review we provide an update on the role of RhoA at the juncture of immune cell activation, inflammation and cardiac disease.

Programmed cell death in stem cell-based therapy: Mechanisms and clinical applications

Stem cell-based therapy raises hopes for a better approach to promoting tissue repair and functional recovery. However, transplanted stem cells show a high death percentage, creating challenges to successful transplantation and prognosis. Thus, it is necessary to investigate the mechanisms underlying stem cell death, such as apoptotic cascade activation, excessive autophagy, inflammatory response, reactive oxygen species, excitotoxicity, and ischemia/hypoxia. Targeting the molecular pathways involved may be an efficient strategy to enhance stem cell viability and maximize transplantation success. Notably, a more complex network of cell death receives more attention than one crucial pathway in determining stem cell fate, highlighting the challenges in exploring mechanisms and therapeutic targets. In this review, we focus on programmed cell death in transplanted stem cells. We also discuss some promising strategies and challenges in promoting survival for further study.

Prognostic Utility of the Combination of Platelet Count with Neutrophil-to-Lymphocyte Ratio in Aged Patients with Acute Myocardial Infarction Undergoing Percutaneous Coronary Intervention

Method

This was a study recording 637 patients who were diagnosed with acute myocardial infarction. Our patients were grouped according to the combination of platelet count and neutrophil-to-lymphocyte ratio. The prognostic role of the combination of platelet count and neutrophil-to-lymphocyte ratio on mortality was assessed by the univariate and multivariate Cox regression analysis.

Result

Our study population was divided into three parts according to the median values of platelet count and neutrophil-to-lymphocyte ratio. It was indicated that platelet count and neutrophil-to-lymphocyte ratio were correlative mutually to a certain degree (p=0.010). The Kaplan–Meier analysis showed that the combination of high platelet count and high neutrophil-to-lymphocyte ratio had a greater risk of death in short- and long-term endpoints (log-rank p=0.046, p < 0.001, respectively). Moreover, by multivariate analysis, both high platelet count and high neutrophil-to-lymphocyte ratio groups were an independent predictor (hazard ratio: 2.132, 95% confidence interval: 1.020–4.454, p=0.044) and long-term mortality (hazard ratio: 2.791, 95% confidence interval: 1.406–5.538, p=0.003).

Conclusion

The combination of platelet count and neutrophil-to-lymphocyte ratio could be a useful predictor for the prediction of in-hospital and long-term mortality in aged patients with acute myocardial infarction.

P. aeruginosa Mediated Necroptosis in Mouse Tumor Cells Induces Long-Lasting Systemic Antitumor Immunity

Necroptosis is a form of programmed cell death (PCD) characterized by RIP3 mediated MLKL activation and increased membrane permeability via MLKL oligomerization. Tumor cell immunogenic cell death (ICD) has been considered to be essential for the anti-tumor response, which is associated with DC recruitment, activation, and maturation. In this study, we found that P. aeruginosa showed its potential to suppress tumor growth and enable long-lasting anti-tumor immunity in vivo. What's more, phosphorylation- RIP3 and MLKL activation induced by P. aeruginosa infection resulted in tumor cell necrotic cell death and HMGB1 production, indicating that P. aeruginosa can cause immunogenic cell death. The necrotic cell death can further drive a robust anti-tumor response via promoting tumor cell death, inhibiting tumor cell proliferation, and modulating systemic immune responses and local immune microenvironment in tumor. Moreover, dying tumor cells killed by P. aeruginosa can catalyze DC maturation, which enhanced the antigen-presenting ability of DC cells. These findings demonstrate that P. aeruginosa can induce immunogenic cell death and trigger a robust long-lasting anti-tumor response along with reshaping tumor microenvironment.

Bibliometric Analysis of the Inflammasome and Pyroptosis in Brain

Background: Considering the pivotal role of inflammasome/pyroptosis in biological function, we visually analyzed the research hotspots of inflammasome/pyroptosis related to the brain in this work through the method of bibliometrics from the Web of Science (WOS) Core database over the past two decades.

Methods: Documents were retrieved from WOS Core Collection on October 16, 2020. The search terms and strategies used for the WOS database are as follow: # 1, “pyroptosis”; # 2, “pyroptotic”; # 3, “inflammasome”; # 4, “pyroptosome”; # 5 “brain”; # 6, “# 1” OR “# 2” OR “# 3” OR “# 4”; # 7, “# 5” AND “# 6”. We selected articles and reviews published in English from 2000 to 2020. Visualization analysis and statistical analysis were performed by VOSviewer 1.6.15 and CiteSpace 5.7. R2.

Results: 1,222 documents were selected for analysis. In the approximately 20 years since the pyroptosis was first presented, the publications regarding the inflammasome and pyroptosis in brain were presented since 2005. The number of annual publications increased gradually over a decade, which are involved in this work, and will continue to increase in 2020. The most prolific country was China with 523 documents but the United States was with 16,328 citations. The most influential author was Juan Pablo de Rivero Vaccari with 27 documents who worked at the University of Miami. The bibliometric analysis showed that inflammasome/pyroptosis involved a variety of brain cell types (microglia, astrocyte, neuron, etc.), physiological processes, ER stress, mitochondrial function, oxidative stress, and disease (traumatic brain injuries, stroke, Alzheimer’s disease, and Parkinson’s disease).

Conclusion: The research of inflammasome/pyroptosis in brain will continue to be the hotspot. We recommend investigating the mechanism of mitochondrial molecules involved in the complex crosstalk of pyroptosis and regulated cell deaths (RCDs) in brain glial cells, which will facilitate the development of effective therapeutic strategies targeting inflammasome/pyroptosis and large-scale clinical trials. Thus, this study presents the trend and characteristic of inflammasome/pyroptosis in brain, which provided a helpful bibliometric analysis for researchers to further studies.

Research trends, hot spots and prospects for necroptosis in the field of neuroscience

There are two types of cell death-apoptosis and necrosis. Apoptosis is cell death regulated by cell signaling pathways, while necrosis has until recently been considered a passive mechanism of cell death caused by environmental pressures. However, recent studies show that necrosis can also be regulated by specific cell signaling pathways. This mode of death, termed necroptosis, has been found to be related to the occurrence and development of many diseases. We used bibliometrics to analyze the global output of literature on necroptosis in the field of neuroscience published in the period 2007–2019 to identify research hotspots and prospects. We included 145 necroptosis-related publications and 2239 references published in the Web of Science during 2007–2019. Visualization analysis revealed that the number of publications related to necroptosis has increased year by year, reaching a peak in 2019. China is the country with the largest number of publications. Key word and literature analyses demonstrated that mitochondrial function change, stroke, ischemia/reperfusion and neuroinflammation are likely the research hotspots and future directions of necroptosis research in the nervous system. The relationship between immune response-related factors, damage-associated molecular patterns, pathogen-associated molecular patterns and necroptosis may become a potential research hotspot in the future. Taken together, our findings suggest that although the inherent limitations of bibliometrics may affect the accuracy of the literature-based prediction of research hotspots, the results obtained from the included publications can provide a reference for the study of necroptosis in the field of neuroscience.

Caspase-8-Dependent Inflammatory Responses Are Controlled by Its Adaptor, FADD, and Necroptosis

Cell death pathways regulate various homeostatic processes. Autoimmune lymphoproliferative syndrome (ALPS) in humans and lymphoproliferative (LPR) disease in mice result from abrogated CD95-induced apoptosis. Because caspase-8 mediates CD95 signaling, we applied genetic approaches to dissect the roles of caspase-8 in cell death and inflammation. Here, we describe oligomerization-deficient Caspase-8^{F122GL123G/F122GL123G} and non-cleavable Caspase-8^D387A/D387A mutant mice with defective caspase-8-mediated apoptosis. Although neither mouse developed LPR disease, removal of the necroptosis effector Mlkl from Caspase-8^D387A/D387A mice revealed an inflammatory role of caspase-8. Ablation of one allele of Fasl, Fadd, or Ripk1 prevented the pathology of Casp8^D387A/D387AMlkl^-/- animals. Removing both Fadd alleles from these mice resulted in early lethality prior to post-natal day 15 (P15), which was prevented by co-ablation of either Ripk1 or Caspase-1. Our results suggest an in vivo role of the inflammatory RIPK1-caspase-8-FADD (FADDosome) complex and reveal a FADD-independent inflammatory role of caspase-8 that involves activation of an inflammasome.

The necroptosis pathway and its role in age-related neurodegenerative diseases: will it open up new therapeutic avenues in the next decade?

INTRODUCTION

Necroptosis is a programmed form of necrotic cell death. Growing evidence demonstrates that necroptosis contributes to cell demise in different pathological conditions including age-dependent neurodegenerative diseases (NDs). These findings open new avenues for understanding the mechanisms of neuronal loss in NDs, which might eventually translate into novel therapeutic interventions.

AREAS COVERED

We reviewed key aspects of necroptosis, in health and disease, focusing on evidence demonstrating its involvement in the pathogenesis of age-related NDs. We then highlight the activation of this pathway in the mechanism of axonal degeneration. We searched on PubMed the literature regarding necroptosis published between 2008 and 2020 and reviewed all publications were necroptosis was studied in the context of age-related NDs.

EXPERT OPINION

Axonal loss and neuronal death are the ultimate consequences of NDs that translate into disease phenotypes. Targeting degenerative mechanisms of the neuron appears as a strategy that might cover a wide range of diseases. Thus, the participation of necroptosis as a common mediator of neuronal demise emerges as a promising target for therapeutic intervention. Considering evidence demonstrating that necroptosis mediates axonal degeneration, we propose and discuss the potential of targeting necroptosis-mediated axonal destruction as a strategy to tackle NDs before neuronal loss occurs.

A perspective on targeting inflammation and cytokine actions in atherosclerosis

Atherosclerosis, a chronic inflammatory disorder of the vasculature that results in cardiovascular disease, continues to pose a significant health and economic burden on modern society. Whilst inflammation has generally been accepted as the key driver of all stages of the disease, it was not until recently that inhibition of a specific proinflammatory cytokine (IL-1β) yielded successful results in the Canakinumab Anti-Inflammatory Thrombosis Outcomes Study trial. This article offers a perspective on targeting inflammation for atherosclerosis, focusing on results of recent Phase III clinical trials, and discusses other potential candidates together with future challenges and prospects.

SIRT3 deficiency delays diabetic skin wound healing via oxidative stress and necroptosis enhancement

Sirtuin 3 (SIRT3) plays a vital role in several dermatological diseases. However, the role and detailed mechanism of SIRT3 in diabetic wound healing are unknown well yet. To explore possible involvement of SIRT3 and necroptosis in diabetic skin wound healing, SIRT3 knockout (KO) mice and 129S1/SvImJ wild‐type (WT) mice were injected with streptozotocin (STZ), and mice skin fibroblasts were exposed to high glucose (HG). It was found that SIRT3 expression decreased in the skin of diabetic patients. SIRT3 deficiency delayed healing rate, reduced blood supply and vascular endothelial growth factor expression, promoted superoxide production, increased malondialdehyde (MDA) levels, decreased total antioxidant capacity (T‐AOC), reduced superoxide dismutase (SOD) activity and aggravated ultrastructure disorder in skin wound of diabetic mice. SIRT3 deficiency inhibited mice skin fibroblasts migration with HG stimulation, which was restored by SIRT3 overexpression. SIRT3 deficiency also suppressed α‐smooth muscle actin (α‐SMA) expression, enhanced superoxide production but decreased mitochondrial membrane potential with HG stimulation after scratch. SIRT3 deficiency further elevated receptor‐interacting protein kinase 3 (RIPK3), RIPK1 and caspase 3 expression both in vitro and in vivo. Collectively, SIRT3 deficiency delayed skin wound healing in diabetes, the mechanism might be related to impaired mitochondria function, enhanced oxidative stress and increased necroptosis. This may provide a novel therapeutic target to accelerate diabetic skin wound healing.