scholarly journals NADPH Oxidase-Mediated Activation of Neutral Sphingomyelinase Is Responsible for Diesel Particulate Extract-Induced Keratinocyte Apoptosis

2020 ◽  
Vol 21 (3) ◽  
pp. 1001 ◽  
Author(s):  
Hyun-Seok Lee ◽  
Hye Yoon Park ◽  
Sung Pil Kwon ◽  
Bogyeong Kim ◽  
Yerin Lee ◽  
...  
Keyword(s):  
Cell Fate ◽  
Air Pollutants ◽  
Specific Inhibitor ◽  
Ros Generation ◽  
Cellular Functions ◽  
Diesel Particulate ◽  
Neutral Sphingomyelinase ◽  
Sphingosine 1 Phosphate ◽  
Pre Treatment ◽  
Diesel Particulate Extract

Human epidermis is positioned at the interface with the external environment, protecting our bodies against external challenges, including air pollutants. Emerging evidence suggests that diesel particulate extract (DPE), a major component of air pollution, leads to impairment of diverse cellular functions in keratinocytes (KC). In this study, we investigated the cellular mechanism underlying DPE-induced KC apoptosis. We first addressed cell death occurring in KC exposed to DPE, paralleled by increased activation of NADPH oxidases (NOXs) and subsequent ROS generation. Blockade of NOX activation with a specific inhibitor attenuated the expected DPE-induced KC apoptosis. In contrast, pre-treatment with a specific inhibitor of reactive oxygen species (ROS) generation did not reverse DPE/NOX-mediated increase in KC apoptosis. We next noted that NOX-mediated KC apoptosis is mainly attributable to neutral sphingomyelinase (SMase)-mediated stimulation of ceramides, which is a well-known pro-apoptotic lipid. Moreover, we found that inhibition of NOX activation significantly attenuated DPE-mediated increase in the ratio of ceramide to its key metabolite sphingosine-1-phosphate (S1P), an important determinant of cell fate. Together, these results suggest that activation of neutral SMase serves as a key downstream signal for the DPE/NOX activation-mediated alteration in ceramide and S1P productions, and subsequent KC apoptosis.

scholarly journals Controlling Redox Status for Stem Cell Survival, Expansion, and Differentiation

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Sébastien Sart ◽  
Liqing Song ◽  
Yan Li
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Disease Modeling ◽  
Redox Status ◽  
Culture Conditions ◽  
Ros Generation ◽  
Cellular Functions ◽  
Proliferation And Differentiation ◽  
Cell Organization

Reactive oxygen species (ROS) have long been considered as pathological agents inducing apoptosis under adverse culture conditions. However, recent findings have challenged this dogma and physiological levels of ROS are now considered as secondary messengers, mediating numerous cellular functions in stem cells. Stem cells represent important tools for tissue engineering, drug screening, and disease modeling. However, the safe use of stem cells for clinical applications still requires culture improvements to obtain functional cells. With the examples of mesenchymal stem cells (MSCs) and pluripotent stem cells (PSCs), this review investigates the roles of ROS in the maintenance of self-renewal, proliferation, and differentiation of stem cells. In addition, this work highlights that the tight control of stem cell microenvironment, including cell organization, and metabolic and mechanical environments, may be an effective approach to regulate endogenous ROS generation. Taken together, this paper indicates the need for better quantification of ROS towards the accurate control of stem cell fate.

scholarly journals Erythrocyte sphingosine kinase regulates intraerythrocytic development of Plasmodium falciparum

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Raj Kumar Sah ◽  
Soumya Pati ◽  
Monika Saini ◽  
Shailja Singh
Keyword(s):  
Plasmodium Falciparum ◽  
Plasma Level ◽  
Growth And Development ◽  
Specific Inhibitor ◽  
Sphingosine Kinase ◽  
Parasite Load ◽  
Mice Model ◽  
Cellular Functions ◽  
Sphingosine 1 Phosphate

AbstractThe sphingolipid pool is key regulator of vital cellular functions in Plasmodium falciparum a causative agent for deadly malaria. Erythrocytes, the host for asexual stage of Plasmodium, are major reservoir for Sphingosine-1-phosphate (S1P). Erythrocyte possesses Sphingosine kinase (SphK) that catalyzed its biosynthesis from sphingosine (Sph). Since, Plasmodium lacks SphK homologous protein it can be envisaged that it co-opts sphingolipids from both intraerythrocytic as well as extracellular pools for its growth and development. Herein, by sphingosine-NBD probing, we report that infected erythrocytes imports Sph from extracellular pool, which is converted to S1P and thereby taken by P. falciparum. Next, by targeting of the SphK through specific inhibitor N,N-Dimethylsphingosine DMS, we show a reduction in erythrocyte endogenous S1P pool and SphK-phosphorylation that led to inhibition in growth and development of ring stage P. falciparum. Owing to the role of S1P in erythrocyte glycolysis we analyzed uptake of NBD-Glucose and production of lactate in DMS treated and untreated plasmodium. DMS treatment led to decreased glycolysis in Plasmodium. Interestingly the host free Plasmodium did not show any effect on glycolysis with DMS treatment indicating its host-mediated effect. Further to understand the in-vivo anti-plasmodial effects of exogenous and endogenous erythrocyte S1P level, Sphingosine-1-phosphate lyase (S1PL) inhibitor (THI), S1P and SphK-1 inhibitor (DMS), were used in Plasmodium berghei ANKA (PbA) mice model. DMS treatment led to reduction of endogenous S1P conferred significant decrease in parasite load, whereas the plasma level S1P modulated by (THI) and exogenous S1P have no effect on growth of Plasmodium. This suggested erythrocyte endogenous S1P pool is important for Plasmodium growth whereas the plasma level S1P has no effect. Altogether, this study provides insight on cellular processes regulated by S1P in P. falciparum and highlights the novel mechanistically distinct molecular target i.e. SphK-1.

Acid ceramidase, a double-edged sword in cancer aggression: A minireview

2020 ◽  
Vol 20 ◽  
Author(s):  
Helen Shiphrah Vethakanraj ◽  
Niveditha Chandrasekaran ◽  
Ashok Kumar Sekar
Keyword(s):  
Cell Fate ◽  
Cancer Progression ◽  
Potential Role ◽  
Tumour Progression ◽  
Acid Ceramidase ◽  
The Core ◽  
The Past ◽  
Sphingosine 1 Phosphate ◽  
Key Enzyme

: Acid ceramidase (AC), the key enzyme of the ceramide metabolic pathway hydrolyzes pro-apoptotic ceramide to sphingosine, which by the action of sphingosine-1-kinase is metabolized to mitogenic sphingosine-1-phosphate. The intracellular level of AC determines ceramide/sphingosine-1-phosphate rheostat which in turn decides the cell fate. The upregulated AC expression during cancerous condition acts as a “double-edged sword” by converting pro-apoptotic ceramide to anti-apoptotic sphingosine-1-phosphate, wherein on one end, the level of ceramide is decreased and on the other end, the level of sphingosine-1-phosphate is increased, thus altogether aggravating the cancer progression. In addition, cancer cells with upregulated AC expression exhibited increased cell proliferation, metastasis, chemoresistance, radioresistance and numerous strategies were developed in the past to effectively target the enzyme. Gene silencing and pharmacological inhibition of AC sensitized the resistant cells to chemo/radiotherapy thereby promoting cell death. The core objective of this review is to explore AC mediated tumour progression and the potential role of AC inhibitors in various cancer cell lines/models.

scholarly journals Modulating Tumor Cell Functions by Tunable Nanopatterned Ligand Presentation

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 212
Author(s):  
Katharina Amschler ◽  
Michael P. Schön
Keyword(s):  
Extracellular Matrix ◽  
Tumor Cell ◽  
Cell Fate ◽  
Epithelial Mesenchymal Transition ◽  
Model Systems ◽  
Cellular Functions ◽  
Biophysical Parameters ◽  
Ligand Density ◽  
Mesenchymal Transition ◽  
Cell Functions

Cancer comprises a large group of complex diseases which arise from the misrouted interplay of mutated cells with other cells and the extracellular matrix. The extracellular matrix is a highly dynamic structure providing biochemical and biophysical cues that regulate tumor cell behavior. While the relevance of biochemical signals has been appreciated, the complex input of biophysical properties like the variation of ligand density and distribution is a relatively new field in cancer research. Nanotechnology has become a very promising tool to mimic the physiological dimension of biophysical signals and their positive (i.e., growth-promoting) and negative (i.e., anti-tumoral or cytotoxic) effects on cellular functions. Here, we review tumor-associated cellular functions such as proliferation, epithelial-mesenchymal transition (EMT), invasion, and phenotype switch that are regulated by biophysical parameters such as ligand density or substrate elasticity. We also address the question of how such factors exert inhibitory or even toxic effects upon tumor cells. We describe three principles of nanostructured model systems based on block copolymer nanolithography, electron beam lithography, and DNA origami that have contributed to our understanding of how biophysical signals direct cancer cell fate.

scholarly journals The Multifaceted Roles of Zinc in Neuronal Mitochondrial Dysfunction

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 489
Author(s):  
Hilary Y. Liu ◽  
Jenna R. Gale ◽  
Ian J. Reynolds ◽  
John H. Weiss ◽  
Elias Aizenman
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Neuronal Damage ◽  
Mitochondrial Fission ◽  
Permeability Transition ◽  
High Energy ◽  
Atp Depletion ◽  
Ros Generation ◽  
Cellular Functions ◽  
Calcium Deregulation ◽  
Energy Demands

Zinc is a highly abundant cation in the brain, essential for cellular functions, including transcription, enzymatic activity, and cell signaling. However, zinc can also trigger injurious cascades in neurons, contributing to the pathology of neurodegenerative diseases. Mitochondria, critical for meeting the high energy demands of the central nervous system (CNS), are a principal target of the deleterious actions of zinc. An increasing body of work suggests that intracellular zinc can, under certain circumstances, contribute to neuronal damage by inhibiting mitochondrial energy processes, including dissipation of the mitochondrial membrane potential (MMP), leading to ATP depletion. Additional consequences of zinc-mediated mitochondrial damage include reactive oxygen species (ROS) generation, mitochondrial permeability transition, and excitotoxic calcium deregulation. Zinc can also induce mitochondrial fission, resulting in mitochondrial fragmentation, as well as inhibition of mitochondrial motility. Here, we review the known mechanisms responsible for the deleterious actions of zinc on the organelle, within the context of neuronal injury associated with neurodegenerative processes. Elucidating the critical contributions of zinc-induced mitochondrial defects to neurotoxicity and neurodegeneration may provide insight into novel therapeutic targets in the clinical setting.

scholarly journals NBS1 is regulated by two kind of mechanisms: ATM-dependent complex formation with MRE11 and RAD50, and cell cycle–dependent degradation of protein

2017 ◽  
Vol 58 (4) ◽  
pp. 487-494 ◽  
Author(s):  
Hui Zhou ◽  
Kasumi Kawamura ◽  
Hiromi Yanagihara ◽  
Junya Kobayashi ◽  
Qiu-Mei Zhang-Akiyama
Keyword(s):  
Dna Damage ◽  
Complex Formation ◽  
Genetic Disorder ◽  
Specific Inhibitor ◽  
Nijmegen Breakage Syndrome ◽  
End Joining ◽  
Mrn Complex ◽  
Pre Treatment ◽  
Non Homologous End Joining ◽  
Cycle Dependent

Abstract Nijmegen breakage syndrome (NBS), a condition similar to Ataxia-Telangiectasia (A-T), is a radiation-hypersensitive genetic disorder showing chromosomal instability, radio-resistant DNA synthesis, immunodeficiency, and predisposition to malignances. The product of the responsible gene, NBS1, forms a complex with MRE11 and RAD50 (MRN complex). The MRN complex is necessary for the DNA damage–induced activation of ATM. However, the regulation of MRN complex formation is still unclear. Here, we investigated the regulatory mechanisms of MRN complex formation. We used an immunoprecipitation assay to determine whether levels of the MRN complex were increased by radiation-induced DNA damage and found that the levels of these proteins and their mRNAs did not increase. ATM-dependent phosphorylation of NBS1 contributed to the DNA damage–induced MRN complex formation. However, pre-treatment of cells with an ATM-specific inhibitor did not affect homologous recombination (HR) and non-homologous end-joining (NHEJ) repair. G0 phase cells, decreasing NBS1 and HR activity but not NHEJ, gained HR-related chromatin association of RAD51 by overexpression of NBS1, suggesting that the amount of NBS1 may be important for repressing accidental activation of HR. These evidences suggest that NBS1 is regulated by two kind of mechanisms: complex formation dependent on ATM, and protein degradation mediated by an unknown MG132-resistant pathway. Such regulation of NBS1 may contribute to cellular responses to double-strand breaks.

scholarly journals Mice Deficient in Sphingosine Kinase 1 Are Rendered Lymphopenic by FTY720

2004 ◽  
Vol 279 (50) ◽  
pp. 52487-52492 ◽  
Author(s):  
Maria L. Allende ◽  
Teiji Sasaki ◽  
Hiromichi Kawai ◽  
Ana Olivera ◽  
Yide Mi ◽  
...  
Keyword(s):  
Vascular Development ◽  
Sphingosine Kinase ◽  
Sphingosine Kinase 1 ◽  
Cellular Functions ◽  
Lymphocyte Trafficking ◽  
Signaling Molecule ◽  
Physiological Functions ◽  
Sphingosine 1 Phosphate ◽  
Sphingosine Kinases ◽  
S1p Receptor

Sphingosine-1-phosphate (S1P), a lipid signaling molecule that regulates many cellular functions, is synthesized from sphingosine and ATP by the action of sphingosine kinase. Two such kinases have been identified, SPHK1 and SPHK2. To begin to investigate the physiological functions of sphingosine kinase and S1P signaling, we generated mice deficient in SPHK1.Sphk1null mice were viable, fertile, and without any obvious abnormalities. Total SPHK activity in mostSphk1-/-tissues was substantially, but not completely, reduced indicating the presence of multiple sphingosine kinases. S1P levels in most tissues from theSphk1-/- mice were not markedly decreased. In serum, however, there was a significant decrease in the S1P level. Although S1P signaling regulates lymphocyte trafficking, lymphocyte distribution was unaffected in lymphoid organs ofSphk1-/- mice. The immunosuppressant FTY720 was phosphorylated and elicited lymphopenia in theSphk1null mice showing that SPHK1 is not required for the functional activation of this sphingosine analogue prodrug. The results with theseSphk1null mice reveal that some key physiologic processes that require S1P receptor signaling, such as vascular development and proper lymphocyte distribution, can occur in the absence of SPHK1.

scholarly journals Redox Buffering Capacity of Nanomaterials as an Index of ROS-based Therapeutics and Toxicity: A Preclinical Animal Study

2021 ◽  
Author(s):  
Aniruddha Adhikari ◽  
Susmita Mondal ◽  
Monojit Das ◽  
Ria Ghosh ◽  
Pritam Biswas ◽  
...  
Keyword(s):  
Therapeutic Index ◽  
Redox Status ◽  
Buffering Capacity ◽  
Engineered Nanoparticles ◽  
Ros Generation ◽  
Cellular Functions ◽  
Physiological Level ◽  
Precise Control ◽  
Preclinical Animal Study ◽  
Intracellular Redox Status

Precise control of intracellular redox status, i.e., maintenance of physiological level of reactive oxygen species (ROS) for mediating normal cellular functions (oxidative eustress) while evading the excess ROS stress (distress) is central to the concept of redox medicine. In this regard, engineered nanoparticles with unique ROS generation, transition, or depletion functions have the potential to be the choice of redox therapeutics. However, it is always challenging to estimate whether ROS-induced intracellular events are beneficial or deleterious to the cell. Here, we propose the concept of redox buffering capacity as a therapeutic index of engineered nanomaterials. As a steady redox state is maintained for normal functioning cells, we hypothesize that the ability of a nanomaterial to preserve this homeostatic condition will dictate its therapeutic efficacy. Additionally, the redox buffering capacity is expected to provide information about the nanoparticle toxicity. Here, using citrate functionalized trimanganese tetroxide nanoparticles (C-Mn3O4 NPs) as a model nanosystem we explored its redox buffering capacity in erythrocytes. Furthermore, we went on to study the chronic toxic effect (if any) of this nanomaterial in animal model in order to co-relate with the experimentally estimated redox buffering capacity. This study could function as a framework for assessing the capability of a nanomaterial as redox medicine (whether maintains eustress or damages by creating distress), thus orienting its application and safety for clinical use.

scholarly journals Hypoxia in Cell Reprogramming and the Epigenetic Regulations

2021 ◽  
Vol 9 ◽  
Author(s):  
Nariaki Nakamura ◽  
Xiaobing Shi ◽  
Radbod Darabi ◽  
Yong Li
Keyword(s):  
Cell Proliferation ◽  
Cell Fate ◽  
Tissue Regeneration ◽  
Cellular Reprogramming ◽  
Cell Reprogramming ◽  
Cell Renewal ◽  
Cellular Functions ◽  
Stem Cell Renewal ◽  
Epigenetic Regulations

Cellular reprogramming is a fundamental topic in the research of stem cells and molecular biology. It is widely investigated and its understanding is crucial for learning about different aspects of development such as cell proliferation, determination of cell fate and stem cell renewal. Other factors involved during development include hypoxia and epigenetics, which play major roles in the development of tissues and organs. This review will discuss the involvement of hypoxia and epigenetics in the regulation of cellular reprogramming and how interplay between each factor can contribute to different cellular functions as well as tissue regeneration.

scholarly journals Clinical Impact of Sphingosine-1-Phosphate in Breast Cancer

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Junko Tsuchida ◽  
Masayuki Nagahashi ◽  
Kazuaki Takabe ◽  
Toshifumi Wakai
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Cancer Metastasis ◽  
Clinical Importance ◽  
Breast Cancer Metastasis ◽  
Lipid Mediator ◽  
Breast Cancer Patients ◽  
Cellular Functions ◽  
Sphingosine 1 Phosphate ◽  
Underlying Mechanisms

Breast cancer metastasizes to lymph nodes or other organs, which determine the prognosis of patients. It is difficult to cure the breast cancer patients with distant metastasis due to resistance to drug therapies. Elucidating the underlying mechanisms of breast cancer metastasis and drug resistance is expected to provide new therapeutic targets. Sphingosine-1-phosphate (S1P) is a pleiotropic, bioactive lipid mediator that regulates many cellular functions, including proliferation, migration, survival, angiogenesis/lymphangiogenesis, and immune responses. S1P is formed in cells by sphingosine kinases and released from them, which acts in an autocrine, paracrine, and/or endocrine manner. S1P in extracellular space, such as interstitial fluid, interacts with components in the tumor microenvironment, which may be important for metastasis. Importantly, recent translational research has demonstrated an association between S1P levels in breast cancer patients and clinical outcomes, highlighting the clinical importance of S1P in breast cancer. We suggest that S1P is one of the key molecules to overcome the resistance to the drug therapies, such as hormonal therapy, anti-HER2 therapy, or chemotherapy, all of which are crucial aspects of a breast cancer treatment.

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