What is the most highest contributor of ROS in the cells?
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The main contributor of reactive oxygen species (ROS) in cells is not mitochondria, as commonly assumed. While mitochondria are a significant source of cellular ROS, they are not necessarily the main contributor under normal conditions . Other major sites/enzymes responsible for cellular ROS production include organelles and metabolic pathways, such as Protoporphyrin IX (PpIX) synthetized from 5-aminolevulinic acid (ALA) . Chemotherapeutic agents also generate ROS that lead to oxidative damage in various molecules of the cell . Additionally, exposure to amorphous nanosilica particles induces a higher level of ROS generation . Furthermore, complex IV (cytochrome c oxidase, COX) is the principal site for ROS generation, with significantly more ROS generated from mitochondria in cancer cells than in normal cells . Therefore, while mitochondria are an important source of cellular ROS, they are not the highest contributor, and other organelles, metabolic pathways, and external factors also play significant roles in ROS production.
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| Papers (4) | Insight |
|---|---|
Open access•Journal Article 4 Citations | The paper does not mention the highest contributor of ROS in the cells. The paper is about the generation of ROS in Langerhans cells treated with different sized amorphous silica particles. |
5 Citations | The paper does not provide information about the highest contributor of ROS in cells. The paper discusses the use of ROS in chemotherapy and the potential benefits of elevating ROS levels to overcome drug resistance in cancer cells. |
44 Citations | The paper does not provide a clear answer to the question of the highest contributor of ROS in cells. It states that mitochondria are a significant source of ROS production but may not be the largest contributor. The paper suggests that more studies are needed to investigate the regulation of ROS production in different cellular conditions. |
Open access•Journal Article 8 Citations | The paper does not mention the highest contributor of ROS in the cells. |
Related Questions
Why do plants produce ROS?5 answersPlants produce reactive oxygen species (ROS) as by-products of aerobic metabolism. ROS are generated in various organelles like chloroplasts, mitochondria, and peroxisomes. These ROS play dual roles in plants: in low concentrations, they act as signaling molecules for normal biological processes and stress responses, aiding in growth and stress tolerance. However, at higher concentrations, ROS can cause oxidative damage to cellular components like lipids, proteins, and DNA, leading to cell death. To maintain ROS at non-damaging levels, plants have evolved enzymatic and non-enzymatic antioxidant systems that regulate ROS levels within cells. Additionally, ROS are involved in mineral and nutrient mobilization and remobilization within plants, contributing to their growth and development.
Which pathway is more commonly involved in oxidative stress?4 answersThe involvement of various pathways in oxidative stress is a complex and multifaceted aspect of cellular biology, with several key signaling pathways being recurrently implicated across different studies. Among these, the nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) signaling pathway is frequently highlighted as a central mechanism in the cellular defense against oxidative stress. This pathway plays a pivotal role in maintaining intracellular homeostasis and protecting cells from oxidative damage by inducing the expression of phase II detoxifying and oxidative-stress responsive genes. The Nrf2/ARE pathway's significance is further underscored by its activation in response to environmental pollutants in aquatic species, indicating its fundamental role across different organisms. Additionally, the pathway's involvement is evident in the context of neurodegeneration, where oxidative stress and mitochondrial damage are key factors, and the modulation of Nrf2/ARE signaling could potentially alleviate symptoms.
Other pathways also play significant roles in the oxidative stress response, including the mitogen-activated protein kinase kinase 5/extracellular signal-regulated kinase 5 (MEK5/ERK5) pathway, which has been identified for its prominent role in the anti-oxidative response across various physiological contexts. The p53 signaling pathway is another critical player, especially in regulating the response of endothelial cells to oxidative stress, highlighting the importance of noncoding-RNAs in this process. Moreover, the DNA damage response (DDR) pathways, such as ATM-Chk2 and ATR-Chk1 checkpoints, are activated in oxidative stress to coordinate DNA repair and cell cycle progression.
While the Nrf2/ARE pathway is more commonly cited across the literature for its broad and fundamental role in combating oxidative stress, it is clear that the cellular response to oxidative stress is multifaceted, involving a complex interplay of multiple signaling pathways. This intricate network of pathways underscores the adaptive capacity of cells to counteract oxidative stress through various mechanisms, highlighting the importance of continued research to fully understand these processes and their implications for human health and disease.
How does ROS are involved in insulin resistance?5 answersReactive oxygen species (ROS) play a role in insulin resistance. In hyperthyroidism, increased ROS levels lead to tissue oxidative stress, which is associated with insulin resistance. Obesity is also linked to insulin resistance, and ROS contribute to its onset and progression. ROS can be generated by overloading the mitochondrial oxidative phosphorylation system and by nicotinamide adenine dinucleotide phosphate oxidases (NOX) produced by adipocytes and macrophages. The source of ROS may differ at different stages of obesity, with NOX4, NOX2, and mitochondria all potentially involved. Additionally, high ROS levels in obesity activate inflammatory pathways and contribute to oxidative stress, leading to insulin resistance. Antioxidant treatment has been explored as a strategy to target ROS and improve glycemic control, but human research in this area has been inconsistent and limited by factors such as treatment context, antioxidant specificity, and bioavailability.
Does elevation of ROS and down-regulation of antioxidant enzyme systems lead to oxidative damage in tissues?4 answersElevation of reactive oxygen species (ROS) and down-regulation of antioxidant enzyme systems can lead to oxidative damage in tissues. In the honey bee, higher ROS production resulting from higher respiratory metabolism in queen larvae is effectively counterbalanced by up-regulation of antioxidant genes, preventing oxidative damage. Oxidative stress, caused by an imbalance between oxidants and antioxidants, can result in oxidative damage to DNA, lipids, and proteins, and has been implicated in several pathologies. Ischemia reperfusion (IR) injury in striated muscles involves excessive ROS accumulation, leading to cellular oxidative stress, mitochondrial dysfunction, and cell death. Hyperoxia, a state of oversupply of oxygen, can increase ROS levels and cause oxidative stress, resulting in lipid damage and heart failure. Therefore, the elevation of ROS and down-regulation of antioxidant enzyme systems can indeed lead to oxidative damage in tissues.
What is the most highest contributor of ROS in the cells under stress?5 answersThe production of reactive oxygen species (ROS) in cells under stress is primarily attributed to the activation of specific enzymes such as nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, fatty acid oxidase, and cell wall oxidases. Additionally, impairment of photosynthetic and mitochondrial electron transport chain (ETC) can also lead to the generation of ROS. Furthermore, stress signals like hypoxia, stress hormones, and high glutamate or glucose levels can increase the cytosolic Ca2+ concentration, which activates a mitochondrial phosphatase that dephosphorylates cytochrome c oxidase (COX). This dephosphorylated COX exhibits no allosteric ATP inhibition, resulting in an increase in mitochondrial membrane potential (ΔΨm) and subsequent ROS formation. Therefore, the activation of specific enzymes and the impairment of electron transport chain play significant roles in the generation of ROS in cells under stress.
Why Are antioxidants used as markers of ROS?5 answersAntioxidants are used as markers of reactive oxygen species (ROS) because they play a crucial role in neutralizing and detoxifying these harmful molecules. ROS are highly reactive and can cause damage to cellular components, leading to various diseases and oxidative stress. Antioxidants act as a defense mechanism by scavenging ROS and preventing their harmful effects. They can donate electrons or hydrogen atoms to ROS, thereby stabilizing them and reducing their reactivity. The quantification of antioxidants provides valuable information about the oxidative stress levels in cells and tissues. Different methods, such as spectrophotometry and fluorometry, are used to measure the activity of antioxidants and ROS. These methods allow for the assessment of the redox balance and the effectiveness of antioxidant defense systems. Understanding the role of antioxidants in combating ROS can help in the development of strategies to mitigate oxidative stress-related diseases and improve overall health and well-being.