MO338INCREASED INFLAMMATORY RESPONSE IS A HALLMARK OF AGE-RELATED AGGRAVATION OF EXPERIMENTAL AKI

Abstract Background and Aims Acute kidney injury (AKI) is associated with elevated mortality and morbidity presenting higher frequency in aged patients. Different mechanisms are activated in AKI, including tubular epithelial cell death (apoptosis and regulated necrosis), inflammatory cell infiltration, impaired mitochondrial function, and prolonged cell-cycle arrest (or cellular senescence). There is a strong connection between pathways activated in AKI and development of cellular senescence, a process implicated in regeneration failure and progression to fibrosis. However, the molecular mechanisms in ageing-associated mortality are not completely understood. Our aim was to investigate age-related molecular mechanisms of AKI. Method Experimental nephropathy by folic acid administration (FA, 125mg/kg) was induced in young (3 months) and old (12 months) mice. Renal lesions and mechanisms were evaluated at 48 hours (AKI acute phase). Results AKI mortality was higher in old (50 %) than in young (15%) mice 4 days after FA injection (pilot study). Tubular damage score (PAS evaluation) and KIM-1 tubular expression (renal damage biomarker) were also higher in old than in young FA-injected mice after 48h. The number of infiltrating immune cells (mainly neutrophils and macrophages) and gene expression levels of proinflammatory genes (Lcn-2 and ccl2) were significantly higher in FA kidneys of old as compared to young mice. Regulated necrosis (necroptosis), contrary to apoptosis, induces an inflammatory response and necroinflammation, being macrophages the key effector immune cells of this cell death pathway. Among some of the key necroptosis mediators, MLKL and RIPK3 were higher in old FA kidneys. These data could indicate a magnification of the inflammatory response to AKI in older mice. In contrast, expression of protective factors was dramatically downregulated in old FA mice, including the mitochondrial biogenesis driver PGC-1α, and the antiaging factor Klotho. Cellular senescence was induced in FA kidneys, as indicated by increased levels of cyclin-dependent kinase inhibitors p16ink4a and p21cip1, and of the DNA Damage Response marker yH2AX. Importantly, p21 mRNA expression and nuclear staining for p21 and yH2AX were increased in FA kidneys, and the fold increase was significantly higher in old than in young mice. Also, the expression of senescence-associated secretory phenotype (SASP) components (Tgfb1, Il-6, and Serpine-1) was significantly higher in old FA mouse kidneys. Interestingly, also some infiltrating immune cells were p21/yH2AX positive, suggesting molecular senescence in the immune cells (“immunesenescence”) and inflammation in the ageing kidney (“inflammaging”) are involved in the aggravated AKI response to FA in old mice. Conclusion Our data indicate that in advanced age, exposure to toxic compounds results in a more severe AKI response that might relate to an early inflammatory response characterize by more extensive necroptosis and activation of pathways related to cellular senescence of resident kidney cells and infiltrating inflammatory cells.

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Acute Kidney Injury is Aggravated in Aged Mice by the Exacerbation of Proinflammatory Processes

Frontiers in Pharmacology ◽

10.3389/fphar.2021.662020 ◽

2021 ◽

Vol 12 ◽

Author(s):

Laura Marquez-Exposito ◽

Lucia Tejedor-Santamaria ◽

Laura Santos-Sanchez ◽

Floris A. Valentijn ◽

Elena Cantero-Navarro ◽

...

Keyword(s):

Acute Kidney Injury ◽

Cell Death ◽

Cellular Senescence ◽

Immune Cells ◽

Kidney Injury ◽

Tubular Cell ◽

Nuclear Staining ◽

Age Related ◽

Regulated Necrosis ◽

Old Mice

Acute kidney injury (AKI) is more frequent in elderly patients. Mechanisms contributing to AKI (tubular cell death, inflammatory cell infiltration, impaired mitochondrial function, and prolonged cell-cycle arrest) have been linked to cellular senescence, a process implicated in regeneration failure and progression to fibrosis. However, the molecular and pathological basis of the age-related increase in AKI incidence is not completely understood. To explore these mechanisms, experimental AKI was induced by folic acid (FA) administration in young (3-months-old) and old (1-year-old) mice, and kidneys were evaluated in the early phase of AKI, at 48 h. Tubular damage score, KIM-1 expression, the recruitment of infiltrating immune cells (mainly neutrophils and macrophages) and proinflammatory gene expression were higher in AKI kidneys of old than of young mice. Tubular cell death in FA-AKI involves several pathways, such as regulated necrosis and apoptosis. Ferroptosis and necroptosis cell-death pathways were upregulated in old AKI kidneys. In contrast, caspase-3 activation was only found in young but not in old mice. Moreover, the antiapoptotic factor BCL-xL was significantly overexpressed in old, injured kidneys, suggesting an age-related apoptosis suppression. AKI kidneys displayed evidence of cellular senescence, such as increased levels of cyclin dependent kinase inhibitors p16ink4a and p21cip1, and of the DNA damage response marker γH2AX. Furthermore, p21cip1 mRNA expression and nuclear staining for p21cip1 and γH2AX were higher in old than in young FA-AKI mice, as well as the expression of senescence-associated secretory phenotype (SASP) components (Il-6, Tgfb1, Ctgf, and Serpine1). Interestingly, some infiltrating immune cells were p21 or γH2AX positive, suggesting that molecular senescence in the immune cells (“immunosenescence”) are involved in the increased severity of AKI in old mice. In contrast, expression of renal protective factors was dramatically downregulated in old AKI mice, including the antiaging factor Klotho and the mitochondrial biogenesis driver PGC-1α. In conclusion, aging resulted in more severe AKI after the exposure to toxic compounds. This increased toxicity may be related to magnification of proinflammatory-related pathways in older mice, including a switch to a proinflammatory cell death (necroptosis) instead of apoptosis, and overactivation of cellular senescence of resident renal cells and infiltrating inflammatory cells.

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Current and Emerging Biomarkers of Cell Death in Human Disease

BioMed Research International ◽

10.1155/2014/690103 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 7

Author(s):

Kongning Li ◽

Deng Wu ◽

Xi Chen ◽

Ting Zhang ◽

Lu Zhang ◽

...

Keyword(s):

Cell Death ◽

Molecular Mechanisms ◽

Research Area ◽

Human Diseases ◽

Mitotic Catastrophe ◽

Regulated Necrosis ◽

Early Diagnose ◽

Multicellular Organisms ◽

The Relationship ◽

Made In

Cell death is a critical biological process, serving many important functions within multicellular organisms. Aberrations in cell death can contribute to the pathology of human diseases. Significant progress made in the research area enormously speeds up our understanding of the biochemical and molecular mechanisms of cell death. According to the distinct morphological and biochemical characteristics, cell death can be triggered by extrinsic or intrinsic apoptosis, regulated necrosis, autophagic cell death, and mitotic catastrophe. Nevertheless, the realization that all of these efforts seek to pursue an effective treatment and cure for the disease has spurred a significant interest in the development of promising biomarkers of cell death to early diagnose disease and accurately predict disease progression and outcome. In this review, we summarize recent knowledge about cell death, survey current and emerging biomarkers of cell death, and discuss the relationship with human diseases.

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Obstructive Sleep Apnea as an Acceleration Trigger of Cellular Senescence Processes through Telomere Shortening

International Journal of Molecular Sciences ◽

10.3390/ijms222212536 ◽

2021 ◽

Vol 22 (22) ◽

pp. 12536

Author(s):

Szymon Turkiewicz ◽

Marta Ditmer ◽

Marcin Sochal ◽

Piotr Białasiewicz ◽

Dominik Strzelecki ◽

...

Keyword(s):

Oxidative Stress ◽

Obstructive Sleep Apnea ◽

Sleep Apnea ◽

Circadian Clock ◽

Chronic Inflammation ◽

Cellular Senescence ◽

Molecular Mechanisms ◽

Telomere Shortening ◽

Age Related ◽

Obstructive Sleep

Obstructive sleep apnea (OSA) is chronic disorder which is characterized by recurrent pauses of breathing during sleep which leads to hypoxia and its two main pathological sequelae: oxidative stress and chronic inflammation. Both are also associated with cellular senescence. As OSA patients present with higher prevalence of age-related disorders, such as atrial hypertension or diabetes mellitus type 2, a relationship between OSA and accelerated aging is observable. Furthermore, it has been established that these OSA are associated with telomere shortening. This process in OSA is likely caused by increased oxidative DNA damage due to increased reactive oxygen species levels, DNA repair disruptions, hypoxia, chronic inflammation, and circadian clock disturbances. The aim of the review is to summarize study outcomes on changes in leukocyte telomere length (LTL) in OSA patients and describe possible molecular mechanisms which connect cellular senescence and the pathophysiology of OSA. The majority of OSA patients are characterized by LTL attrition due to oxidative stress, hypoxia and inflammation, which make a kind of positive feedback loop, and circadian clock disturbance.

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Molecular basis of disregulation of programmed lymphocytes’ death in chronic viral infection

Bulletin of Siberian Medicine ◽

10.20538/1682-0363-2006-2-23-34 ◽

2006 ◽

Vol 5 (2) ◽

pp. 23-34

Author(s):

V. V. Novitsky ◽

N. V. Ryazantseva ◽

O. B. Zhoukova

Keyword(s):

Cell Death ◽

Programmed Cell Death ◽

Viral Infection ◽

Immune Cells ◽

Molecular Basis ◽

Molecular Mechanisms ◽

Recent Literature ◽

Chronic Viral Infection ◽

Persistent Viruses

The review analyses information from recent literature and results of the authors’ own investigations concerning imbalance of programmed cell death in forming chronic viral infection. Molecular mechanisms of apoptosis modulation of immune cells by persistent viruses are discussed in the article.

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Cellular Senescence in Renal and Urinary Tract Disorders

Cells ◽

10.3390/cells9112420 ◽

2020 ◽

Vol 9 (11) ◽

pp. 2420

Author(s):

Yohan Santin ◽

Philippe Lluel ◽

Pascal Rischmann ◽

Xavier Gamé ◽

Jeanne Mialet-Perez ◽

...

Keyword(s):

Urinary Tract ◽

Cellular Senescence ◽

Molecular Mechanisms ◽

Therapeutic Potential ◽

Senescent Cell ◽

Post Injury ◽

Urinary Tract Disorders ◽

Age Related ◽

Adverse Remodeling ◽

Bladder Disorders

Cellular senescence is a state of cell cycle arrest induced by repetitive cell mitoses or different stresses, which is implicated in various physiological or pathological processes. The beneficial or adverse effects of senescent cells depend on their transitory or persistent state. Transient senescence has major beneficial roles promoting successful post-injury repair and inhibiting malignant transformation. On the other hand, persistent accumulation of senescent cells has been associated with chronic diseases and age-related illnesses like renal/urinary tract disorders. The deleterious effects of persistent senescent cells have been related, in part, to their senescence-associated secretory phenotype (SASP) characterized by the release of a variety of factors responsible for chronic inflammation, extracellular matrix adverse remodeling, and fibrosis. Recently, an increase in senescent cell burden has been reported in renal, prostate, and bladder disorders. In this review, we will summarize the molecular mechanisms of senescence and their implication in renal and urinary tract diseases. We will also discuss the differential impacts of transient versus persistent status of cellular senescence, as well as the therapeutic potential of senescent cell targeting in these diseases.

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Eosinophil Cell Death Determination: Role for ERK in the Mechanism Regulating Decision Between Eosinophil Activation, Apoptosis or Regulated Necrosis.

Blood ◽

10.1182/blood.v120.21.2134.2134 ◽

2012 ◽

Vol 120 (21) ◽

pp. 2134-2134

Author(s):

Gen Kano ◽

Maha Almanan ◽

Bruce Bochner ◽

Nives Zimmermann

Keyword(s):

Cell Death ◽

Conflicts Of Interest ◽

Membrane Integrity ◽

Annexin V ◽

Ros Production ◽

Survival Factor ◽

Cell Death Pathway ◽

Eosinophil Cell ◽

Regulated Necrosis ◽

Eosinophil Activation

Abstract Abstract 2134 Siglec-8 is a membrane protein predominantly expressed on eosinophils, where its ligation induces cell death. Paradoxically, Siglec-8-induced cell death is markedly enhanced by the eosinophil activation and survival factor IL-5. Thus, Siglec-8 induces cell death preferentially in activated eosinophils, making it an attractive therapeutic target for eosinophil-mediated diseases. However, the mechanism of this survival factor-enhanced cell death is not known. While Siglec-8 ligation (by anti-Siglec-8 antibody) induces caspase-dependent apoptosis in resting eosinophils, it induces caspase-independent cell death in activated eosinophils. We hypothesize that co-stimulating the Siglec-8 and IL-5 pathways induces a necrotic cell death pathway. By morphologically characterizing human peripheral blood eosinophils as “apoptotic” (i.e., shrunk cells with condensed chromatin) or “necrotic” (i.e., swollen cells, disrupted membrane integrity), we found that anti-Siglec-8 + IL-5 co-stimulation yielded more necrotic eosinophils (P = 0.055, 6 donors) than stimulation with anti-Siglec-8 alone. Additionally, we stained with Annexin V and 7AAD and assessed the percent of Annexin V+ cells that are 7AAD+ as an indicator of increased transition of apoptotic cells to secondary necrosis and/or cells dying primarily by necrosis. We found that anti-Siglec-8 + IL-5 co-stimulated cells had a higher ratio of 7AAD+ cells compared with cells treated with anti-Siglec-8 alone (P < 0.001, 25 experiments with 11 independent donors). This higher 7AAD+ ratio, the morphological characteristics and the caspase-independent cell death of co-stimulated cells suggest that Siglec-8 ligation induces a necrotic form of cell death in IL-5-stimulated eosinophils by activating a specific and distinct biochemical pathway. Our previous studies have shown that reactive oxygen species (ROS) production is involved in Siglec-8-induced cell death in both resting and activated eosinophils. However, we have observed that phosphorylation of ERK1/2 and MEK1 was significantly increased in cells co-stimulated with anti-Siglec-8 + IL-5 compared to cells stimulated with IL-5 alone; anti-Siglec-8 alone did not cause ERK1/2 phosphorylation. MEK1 inhibitors U0126 and PD184352 completely blocked anti-Siglec-8 + IL-5-induced cell death; however, intracellular ROS production induced by Siglec-8 ligation was MEK1-independent. In contrast, the ROS inhibitor DPI prevented the anti-Siglec-8 + IL-5-induced enhancement of ERK1/2 phosphorylation and subsequent cell death. Enhanced ROS accumulation in IL-5 treated cells was sufficient to induce enhanced cell death, similar to anti-Siglec-8 treatment. These findings suggest that Siglec-8 ligation leads to ROS-dependent enhancement of IL-5-induced ERK1/2 phosphorylation, which results in enhanced Siglec-8-induced eosinophil cell death. How ERK phosphorylation induces cell death in co-stimulated eosinophils is not known, and ERK's involvement is surprising considering its role in activation of IL-5-stimulated eosinophils. However, recent studies have shown that ERK can be involved in specific types of cell death, namely necroptosis or autophagy, and that spatiotemporal parameters determine whether ERK will induce cell death or activation. Thus, we hypothesized that ERK localization will be altered in eosinophils co-stimulated with anti-Siglec-8 + IL-5 compared with cells treated with IL-5 alone. Western blotting of nuclear and cytoplasmic fractions and immunofluorescence suggest that enhanced ERK1/2 localization and phosphorylation are sustained for at least 2 hours in the nucleus of anti-Siglec-8 + IL-5 co-stimulated cells; cells treated with IL-5 alone have only brief ERK1/2 nuclear localization. The sustained nuclear activation of ERK may explain the change in IL-5 function from eosinophil activation/survival to necrotic death upon Siglec-8 ligation. In summary, ERK is involved in regulating the decision point for eosinophil activation, apoptosis or regulated necrosis. Disclosures: No relevant conflicts of interest to declare.

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Necroptosis contributes to chronic inflammation and fibrosis in aging liver

10.1101/2021.09.19.460953 ◽

2021 ◽

Author(s):

Sabira Mohammed ◽

Nidheesh Thadathil ◽

Ramasamy Selvarani ◽

Evan H Nicklas ◽

Dawei Wang ◽

...

Keyword(s):

Chronic Inflammation ◽

Proinflammatory Cytokines ◽

Term Treatment ◽

Low Grade ◽

Short Term Treatment ◽

M1 Macrophages ◽

Cell Death Pathway ◽

Age Related ◽

Old Mice ◽

Young Mice

Inflammaging, characterized by an increase in low-grade chronic inflammation with age, is a hallmark of aging and is strongly associated with various age-related diseases, including chronic liver disease (CLD) and hepatocellular carcinoma (HCC). Because necroptosis is a cell death pathway that induces inflammation through the release of DAMPs, we tested the hypothesis that age-associated increase in necroptosis contributes to chronic inflammation in aging liver. Phosphorylation of MLKL and MLKL-oligomers, markers of necroptosis, as well as phosphorylation of RIPK3 and RIPK1 were significantly upregulated in the livers of old mice relative to young mice and this increase occurred in the later half of life (i.e., after 18 months of age). Markers of M1 macrophages, expression of proinflammatory cytokines (TNFα, IL6 and IL-1β), and markers of fibrosis were significantly upregulated in the liver with age and the change in necroptosis paralleled the changes in inflammation and fibrosis. Hepatocytes and liver macrophages isolated from old mice showed elevated levels of necroptosis markers as well as increased expression of proinflammatory cytokines relative to young mice. Short term treatment with the necroptosis inhibitor, necrostatin-1s (Nec-1s), reduced necroptosis, markers of M1 macrophages, expression of proinflammatory cytokines, and markers of fibrosis in the livers of old mice. Thus, our data show for the first time that liver aging is associated with increased necroptosis and necroptosis contributes to chronic inflammation in the liver, which in turn appears to contribute to liver fibrosis and possibly CLD.

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Role of CNC1 gene in TDP-43 aggregation-induced oxidative stress-mediated cell death in S. cerevisiae model of ALS

10.1101/2020.03.05.978411 ◽

2020 ◽

Author(s):

Vidhya Bharathi ◽

Amandeep Girdhar ◽

Basant K Patel

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Stress Response ◽

Molecular Mechanisms ◽

Motor Neuron Diseases ◽

C Protein ◽

Cell Death Pathway ◽

Cyclin C ◽

Dependent Cell ◽

Anti Oxidant

ABSTRACTTDP-43 is a multi-functional ribonucleoprotein that is also found deposited as hyper-phosphorylated and ubiquitinated TDP-43 inclusions in the brain and spinal cord of the patients of the motor neuron diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Till date, how the cell death ensues is not fully deciphered although several molecular mechanisms of the TDP-43 toxicity such as impairments of endocytosis and chromatin remodelling, mis-regulations of autophagy and proteasome function, mis-localization to the mitochondria and generation of oxidative stress etc., have been proposed. A predominantly nuclear protein, Cyclin C, can regulate the oxidative stress response by affecting the transcription of stress response genes and also by translocation to the cytoplasm for the activation of the mitochondrial fragmentation-dependent cell death pathway. Using the well-established yeast model of TDP-43 aggregation and toxicity, we examined here whether upon TDP-43 aggregation, the cell survival depends on the presence of the CNC1 gene that encodes Cyclin C protein or other genes that encode proteins that function in conjunction with Cyclin C, such as the DNM1, FIS1 and MED13 genes. We found that the TDP-43 toxicity is significantly reduced in the yeast deleted for the CNC1 or DNM1 genes. Importantly, the rescue of TDP-43 toxicity in these yeast deletion backgrounds required the presence of functional mitochondria. Also, the deletion of YBH3 gene, which encodes for a protein involved in the mitochondria-dependent apoptosis, also reduced the TDP-43 toxicity. Furthermore, Cyclin C-YFP was observed to localize from the nucleus to the cytoplasm in response to the TDP-43 co-expression. Also, this cytoplasmic localization of Cyclin C was prevented by the addition of an anti-oxidant molecule, N-acetyl-cysteine. Taken together, our data suggest that Cyclin C, Dnm1 and Ybh3 proteins are important in mediating the TDP-43-induced oxidative stress-mediated cell death in the S. cerevisiae model.

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Crosstalk between Oxidative Stress and Ferroptosis/Oxytosis in Ischemic Stroke: Possible Targets and Molecular Mechanisms

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/6643382 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Jia-Xin Ren ◽

Chao Li ◽

Xiu-Li Yan ◽

Yang Qu ◽

Yi Yang ◽

...

Keyword(s):

Oxidative Stress ◽

Lipid Peroxidation ◽

Cell Death ◽

Ischemic Stroke ◽

Molecular Mechanisms ◽

Glutathione Depletion ◽

Molecular Pathways ◽

Neuronal Dysfunction ◽

Cell Death Pathway

Oxidative stress is a key cause of ischemic stroke and an initiator of neuronal dysfunction and death, mainly through the overproduction of peroxides and the depletion of antioxidants. Ferroptosis/oxytosis is a unique, oxidative stress-induced cell death pathway characterized by lipid peroxidation and glutathione depletion. Both oxidative stress and ferroptosis/oxytosis have common molecular pathways. This review summarizes the possible targets and the mechanisms underlying the crosstalk between oxidative stress and ferroptosis/oxytosis in ischemic stroke. This knowledge might help to further understand the pathophysiology of ischemic stroke and open new perspectives for the treatment of ischemic stroke.

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Similarities and interplay between senescent cells and macrophages

The Journal of Cell Biology ◽

10.1083/jcb.202010162 ◽

2020 ◽

Vol 220 (2) ◽

Author(s):

Jacques Behmoaras ◽

Jesús Gil

Keyword(s):

Tumor Microenvironment ◽

Cellular Senescence ◽

Immune Cells ◽

Molecular Mechanisms ◽

Senescent Cell ◽

Phenotypic Characteristics ◽

Effector Functions ◽

Inflammatory Conditions ◽

Secretory Phenotype ◽

Cancerous Cells

Senescence is a cellular program that prevents the replication of old, damaged, or cancerous cells. Senescent cells become growth arrested and undergo changes in their morphology, chromatin organization, and metabolism, and produce a bioactive secretome. This secretome, the senescence-associated secretory phenotype (SASP), mediates many of the pathophysiological effects associated with senescent cells, for example, recruiting and activating immune cells such as macrophages. The relation between senescent cells and macrophages is intriguing: senescent cells recruit macrophages, can induce them to undergo senescence, or can influence their polarization. Senescent cells and macrophages share multiple phenotypic characteristics; both have a high secretory status, increased lysosome numbers, or the ability to activate the inflammasome. Senescent cells accumulate during aging and disease, and killing them results in widespread benefits. Here we discuss similarities between senescent cells and macrophages and interpret the latest developments in macrophage biology to understand the molecular mechanisms of cellular senescence. We describe evidence and effects of senescence in macrophages and speculate on the ontogeny of the senescent-like state in macrophages. Finally, we examine the macrophage–senescent cell interplay and its impact on macrophage effector functions during inflammatory conditions and in the tumor microenvironment.

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