Mitochondrial oxygen sensing: regulation of hypoxia-inducible factor by mitochondrial generated reactive oxygen species

2007 ◽  
Vol 43 ◽  
pp. 17-28 ◽  
Author(s):  
Eric L. Bell ◽  
Navdeep S. Chandel

Decreased oxygen availability (hypoxia) promotes physiological processes such as energy metabolism, angiogenesis, cell proliferation and cell viability through the transcription factor HIF (hypoxia-inducible factor). Activation of HIF can also promote pathophysiological processes such as cancer and pulmonary hypertension. The mechanism(s) by which hypoxia activates HIF are the subject of intensive research. In this chapter we outline the model in which mitochondria regulate the stability of HIF through the increased production of ROS (reactive oxygen species) during hypoxia.

2019 ◽  
Vol 39 (8) ◽  
Author(s):  
Nicholas W. Eyrich ◽  
Chad R. Potts ◽  
M. Hope Robinson ◽  
Victor Maximov ◽  
Anna M. Kenney

ABSTRACT Cerebellar development is a highly regulated process involving numerous factors acting with high specificity, both temporally and by location. Part of this process involves extensive proliferation of cerebellar granule neuron precursors (CGNPs) induced by Sonic Hedgehog (SHH) signaling, but downstream effectors of mitogenic signaling are still being elucidated. Using primary CGNP cultures, a well-established model for SHH-driven proliferation, we show that SHH-treated CGNPs feature high levels of hypoxia-inducible factor 1α (HIF1α), which is known to promote glycolysis, stemness, and angiogenesis. In CGNPs cultured under normoxic conditions, HIF1α is posttranslationally stabilized in a manner dependent upon reactive oxygen species (ROS) and NADPH oxidase (NOX), both of which are also upregulated in these cells. Inhibition of NOX activity resulted in HIF1α destabilization and reduced levels of cyclin D2, a marker of CGNP proliferation. As CGNPs are the putative cells of origin for the SHH subtype of medulloblastoma and aberrant SHH signaling is implicated in other neoplasms, these studies may also have future relevance in the context of cancer. Taken together, our findings suggest that a better understanding of nonhypoxic HIF1α stabilization through NOX-induced ROS generation can provide insights into normal cell proliferation in cerebellar development and SHH-driven cell proliferation in cancers with aberrant SHH signaling.


The Analyst ◽  
2021 ◽  
Author(s):  
Ya-Nan Wei ◽  
Bo Lin ◽  
Yang Shu ◽  
Jian-Hua Wang

As an indispensable biothiol, cysteine (Cys) plays a critical part in cellular redox homeostasis, pathological and physiological processes. One of the main sources of reactive oxygen species (ROS) in human...


2021 ◽  
pp. 074823372110110
Author(s):  
Shabnoor Iqbal ◽  
Farhat Jabeen ◽  
Abdul Shakoor Chaudhry ◽  
Muhammad Ajmal Shah ◽  
Gaber El-Saber Batiha

Nickel nanoparticles (Ni-NPs) are widely used for multiple purposes in industries. Ni-NPs exposure is detrimental to ecosystems owing to widespread use, and so their toxicity is important to consider for real-world applications. This review mainly focuses on the notable pathophysiological activities of Ni-NPs in various research models. Ni-NPs are stated to be more toxic than bulk forms because of their larger surface area to volume ratio and are reported to provoke toxicity through reactive oxygen species generation, which leads to the upregulation of nuclear factor-κB and promotes further signaling cascades. Ni-NPs may contribute to provoking oxidative stress and apoptosis. Hypoxia-inducible factor 1α and mitogen-activated protein kinases pathways are involved in Ni-NPs associated toxicity. Ni-NPs trigger the transcription factors p-p38, p-JNK, p-ERK1/2, interleukin (IL)-3, TNF-α, IL-13, Fas, Cyt c, Bax, Bid protein, caspase-3, caspase-8, and caspase-9. Moreover, Ni-NPs have an occupational vulnerability and were reported to induce lung-related disorders owing to inhalation. Ni-NPs may cause serious effects on reproduction as Ni-NPs induced deleterious effects on reproductive cells (sperm and eggs) in animal models and provoked hormonal alteration. However, recent studies have provided limited knowledge regarding the important checkpoints of signaling pathways and less focused on the toxic limitation of Ni-NPs in humans, which therefore needs to be further investigated.


2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi37-vi37
Author(s):  
Gabrielle Price ◽  
Daniel Rivera ◽  
Alexandros Bouras ◽  
Constantinos Hadjipanayis

Abstract Diffuse midline gliomas (DMGs) are highly invasive, unresectable tumors in children. To date, there is no effective treatment for DMGs. Fractionated radiotherapy (RT), currently the standard of care, has provided limited disease control. Current obstacles to treatment include the blood brain barrier (BBB) that limits systemic drug delivery, tumor therapy resistance, and brainstem infiltration. Given the unmet need for more effective DMG treatments, photodynamic therapy (PDT), with the precursor photosensitizing agent 5-aminolevulinic acid (5-ALA), is an oncologic treatment that holds promise. 5-ALA PDT of tumors occurs by targeting tumor cells that accumulate the 5-ALA metabolite, protoporphyrin IX (PPIX), with 635 nm light to create deadly reactive oxygen species (ROS). We explore the synergism of 5-ALA PDT with the MEK inhibitor, trametinib, since the RAS/MEK signaling pathway regulates tumor cell proliferation and survival and has been shown to therapeutically enhance PDT in select tumor models. We demonstrated that sub-micromolar levels of 5-ALA PDT and nanomolar levels of trametinib successfully decrease cell proliferation and induce apoptosis in multiple DMG cell lines. Cell viability assays revealed that drug response differs based on the histone mutation (H3.1 or H3.3) of the line. Mechanisms of decreased cell survival involves the generation of reactive oxygen species that induces programmed cell death. Through the use of a DMG genetically engineered mouse model, we also found 5-ALA PDT to induce apoptosis in vivo. The synergistic effects of MEK inhibition and 5-ALA PDT in vitro and apoptotic effects of 5-ALA PDT in vivo, highlights the potential therapeutic efficacy of this treatment modality.


2021 ◽  
Vol 67 (2) ◽  
pp. 44-52
Author(s):  
N.G. Zemlianskykh ◽  
◽  
L.O. Babiychuk ◽  

Protein modifications in the membrane-cytoskeleton complex (MCC) of human erythrocytes, as well as changes in the intensity of reactive oxygen species (ROS) production upon cell cryopreservation with polyethylene glycol (PEG) were investigated. The protein profile of ghosts of erythrocytes frozen with PEG has common features with both the control and cells frozen without cryoprotectant. PEG makes it possible to restrict the structural rearrangements of the main MCC proteins under the effect of extreme factors and to restrain the amount of high molecular weight polypeptide complexes induced by the protein-cross-linking reagent diamide at the control level, in contrast to cells frozen without a cryoprotectant. However, changes related to the protein peroxiredoxin 2 in ghosts of erythrocytes cryopreserved with PEG are also attributed to cells frozen without a cryoprotectant that may be associated with the activation of oxidative processes. This is evidenced by a 10-fold increase in ROS formation in erythrocytes frozen under PEG protection. Thus, upon cryopreservation of erythrocytes with PEG, certain disorders in MCC proteins may be associated with increased formation of ROS, which may contribute to the disorganization of the structural components of MCC and disrupt the stability of cryopreserved cells under physiological conditions.


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