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Nature Communications Jun 2024One open question in the biology of growth factor receptors is how a quantitative input (i.e., ligand concentration) is decoded by the cell to produce specific...
One open question in the biology of growth factor receptors is how a quantitative input (i.e., ligand concentration) is decoded by the cell to produce specific response(s). Here, we show that an EGFR endocytic mechanism, non-clathrin endocytosis (NCE), which is activated only at high ligand concentrations and targets receptor to degradation, requires a tripartite organelle platform involving the plasma membrane (PM), endoplasmic reticulum (ER) and mitochondria. At these contact sites, EGFR-dependent, ER-generated Ca oscillations are sensed by mitochondria, leading to increased metabolism and ATP production. Locally released ATP is required for cortical actin remodeling and EGFR-NCE vesicle fission. The same biochemical circuitry is also needed for an effector function of EGFR, i.e., collective motility. The multiorganelle signaling platform herein described mediates direct communication between EGFR signaling and mitochondrial metabolism, and is predicted to have a broad impact on cell physiology as it is activated by another growth factor receptor, HGFR/MET.
Topics: Mitochondria; ErbB Receptors; Endoplasmic Reticulum; Humans; Signal Transduction; Adenosine Triphosphate; Endocytosis; Animals; Cell Membrane; Calcium Signaling; Calcium
PubMed: 38879572
DOI: 10.1038/s41467-024-49543-z -
Biomedicine & Pharmacotherapy =... Jun 2024Myocardial reperfusion injury occurs when blood flow is restored after ischemia, an essential process to salvage ischemic tissue. However, this phenomenon is intricate,... (Review)
Review
Myocardial reperfusion injury occurs when blood flow is restored after ischemia, an essential process to salvage ischemic tissue. However, this phenomenon is intricate, characterized by various harmful effects. Tissue damage in ischemia-reperfusion injury arises from various factors, including the production of reactive oxygen species, the sequestration of proinflammatory immune cells in ischemic tissues, the induction of endoplasmic reticulum stress, and the occurrence of postischemic capillary no-reflow. Secretory phospholipase A2 (sPLA2) plays a crucial role in the eicosanoid pathway by releasing free arachidonic acid from membrane phospholipids' sn-2 position. This liberated arachidonic acid serves as a substrate for various eicosanoid biosynthetic enzymes, including cyclooxygenases, lipoxygenases, and cytochromes P450, ultimately resulting in inflammation and an elevated risk of reperfusion injury. Therefore, the activation of sPLA2 directly correlates with the heightened and accelerated damage observed in myocardial ischemia-reperfusion injury (MIRI). Presently, clinical trials are in progress for medications aimed at sPLA2, presenting promising avenues for intervention. Cardiolipin (CL) plays a crucial role in maintaining mitochondrial function, and its alteration is closely linked to mitochondrial dysfunction observed in MIRI. This paper provides a critical analysis of CL modifications concerning mitochondrial dysfunction in MIRI, along with its associated molecular mechanisms. Additionally, it delves into various pharmacological approaches to prevent or alleviate MIRI, whether by directly targeting mitochondrial CL or through indirect means.
PubMed: 38878685
DOI: 10.1016/j.biopha.2024.116936 -
Clinical and Translational Medicine Jun 2024Smoking is recognised as an independent risk factor in the development of chronic pancreatitis (CP). Cystic fibrosis transmembrane conductance regulator (CFTR) function...
BACKGROUND AND AIMS
Smoking is recognised as an independent risk factor in the development of chronic pancreatitis (CP). Cystic fibrosis transmembrane conductance regulator (CFTR) function and ductal fluid and bicarbonate secretion are also known to be impaired in CP, so it is crucial to understand the relationships between smoking, pancreatic ductal function and the development of CP.
METHODS
We measured sweat chloride (Cl) concentrations in patients with and without CP, both smokers and non-smokers, to assess CFTR activity. Serum heavy metal levels and tissue cadmium concentrations were determined by mass spectrometry in smoking and non-smoking patients. Guinea pigs were exposed to cigarette smoke, and cigarette smoke extract (CSE) was prepared to characterise its effects on pancreatic HCO and fluid secretion and CFTR function. We administered cerulein to both the smoking and non-smoking groups of mice to induce pancreatitis.
RESULTS
Sweat samples from smokers, both with and without CP, exhibited elevated Cl concentrations compared to those from non-smokers, indicating a decrease in CFTR activity due to smoking. Pancreatic tissues from smokers, regardless of CP status, displayed lower CFTR expression than those from non-smokers. Serum levels of cadmium and mercury, as well as pancreatic tissue cadmium, were increased in smokers. Smoking, CSE, cadmium, mercury and nicotine all hindered fluid and HCO secretion and CFTR activity in pancreatic ductal cells. These effects were mediated by sustained increases in intracellular calcium ([Ca]), depletion of intracellular ATP (ATP) and mitochondrial membrane depolarisation.
CONCLUSION
Smoking impairs pancreatic ductal function and contributes to the development of CP. Heavy metals, notably cadmium, play a significant role in the harmful effects of smoking.
KEY POINTS
Smoking and cigarette smoke extract diminish pancreatic ductal fluid and HCO secretion as well as the expression and function of CFTR Cd and Hg concentrations are significantly higher in the serum samples of smokers Cd accumulates in the pancreatic tissue of smokers.
Topics: Humans; Pancreatitis, Chronic; Animals; Metals, Heavy; Male; Mice; Female; Middle Aged; Guinea Pigs; Adult; Pancreatic Ducts; Cystic Fibrosis Transmembrane Conductance Regulator; Smoking; Disease Models, Animal
PubMed: 38877637
DOI: 10.1002/ctm2.1733 -
Cellular & Molecular Biology Letters Jun 2024Osteoarthritis (OA) is the most common degenerative joint disorder that causes disability in aged individuals, caused by functional and structural alterations of the...
Osteoarthritis (OA) is the most common degenerative joint disorder that causes disability in aged individuals, caused by functional and structural alterations of the knee joint. To investigate whether metabolic drivers might be harnessed to promote cartilage repair, a liquid chromatography-mass spectrometry (LC-MS) untargeted metabolomics approach was carried out to screen serum biomarkers in osteoarthritic rats. Based on the correlation analyses, α-ketoglutarate (α-KG) has been demonstrated to have antioxidant and anti-inflammatory properties in various diseases. These properties make α-KG a prime candidate for further investigation of OA. Experimental results indicate that α-KG significantly inhibited HO-induced cartilage cell matrix degradation and apoptosis, reduced levels of reactive oxygen species (ROS) and malondialdehyde (MDA), increased superoxide dismutase (SOD) and glutathione (GSH)/glutathione disulfide (GSSG) levels, and upregulated the expression of ETV4, SLC7A11 and GPX4. Further mechanistic studies observed that α-KG, like Ferrostatin-1 (Fer-1), effectively alleviated Erastin-induced apoptosis and ECM degradation. α-KG and Fer-1 upregulated ETV4, SLC7A11, and GPX4 at the mRNA and protein levels, decreased ferrous ion (Fe) accumulation, and preserved mitochondrial membrane potential (MMP) in ATDC5 cells. In vivo, α-KG treatment inhibited ferroptosis in OA rats by activating the ETV4/SLC7A11/GPX4 pathway. Thus, these findings indicate that α-KG inhibits ferroptosis via the ETV4/SLC7A11/GPX4 signaling pathway, thereby alleviating OA. These observations suggest that α-KG exhibits potential therapeutic properties for the treatment and prevention of OA, thereby having potential clinical applications in the future.
Topics: Ferroptosis; Animals; Osteoarthritis; Ketoglutaric Acids; Signal Transduction; Rats; Phospholipid Hydroperoxide Glutathione Peroxidase; Amino Acid Transport System y+; Male; Proto-Oncogene Proteins c-ets; Rats, Sprague-Dawley; Apoptosis; Reactive Oxygen Species
PubMed: 38877424
DOI: 10.1186/s11658-024-00605-6 -
Scientific Reports Jun 2024Acute promyelocytic leukemia (APL) is characterized by rearrangements of the retinoic acid receptor, RARα, which makes all-trans retinoic acid (ATRA) highly effective...
Acute promyelocytic leukemia (APL) is characterized by rearrangements of the retinoic acid receptor, RARα, which makes all-trans retinoic acid (ATRA) highly effective in the treatment of this disease, inducing promyelocytes differentiation. Current therapy, based on ATRA in combination with arsenic trioxide, with or without chemotherapy, provides high rates of event-free survival and overall survival. However, a decline in the drug activity, due to increased ATRA metabolism and RARα mutations, is often observed over long-term treatments. Furthermore, dedifferentiation can occur providing relapse of the disease. In this study we evaluated fenretinide, a semisynthetic ATRA derivative, encapsulated in nanomicelles (nano-fenretinide) as an alternative treatment to ATRA in APL. Nano-fenretinide was prepared by fenretinide encapsulation in a self-assembling phospholipid mixture. Physico-chemical characterization was carried out by dinamic light scattering and spectrophotometry. The biological activity was evaluated by MTT assay, flow cytometry and confocal laser-scanning fluorescence microscopy. Nano-fenretinide induced apoptosis in acute promyelocytic leukemia cells (HL60) by an early increase of reactive oxygen species and a mitochondrial potential decrease. The fenretinide concentration that induced 90-100% decrease in cell viability was about 2.0 µM at 24 h, a concentration easily achievable in vivo when nano-fenretinide is administered by oral or intravenous route, as demonstrated in previous studies. Nano-fenretinide was effective, albeit at slightly higher concentrations, also in doxorubicin-resistant HL60 cells, while a comparison with TK6 lymphoblasts indicated a lack of toxicity on normal cells. The results indicate that nano-fenretinide can be considered an alternative therapy to ATRA in acute promyelocytic leukemia when decreased efficacy, resistance or recurrence of disease emerge after protracted treatments with ATRA.
Topics: Humans; Fenretinide; Leukemia, Promyelocytic, Acute; HL-60 Cells; Apoptosis; Reactive Oxygen Species; Antineoplastic Agents; Nanoparticles; Cell Survival; Micelles; Membrane Potential, Mitochondrial
PubMed: 38877119
DOI: 10.1038/s41598-024-64629-w -
Phytomedicine : International Journal... May 2024Although AMP-activated protein kinase (AMPK) has been extensively studied in cellular processes, the understanding of its substrates, downstream functions, contributions...
BACKGROUND
Although AMP-activated protein kinase (AMPK) has been extensively studied in cellular processes, the understanding of its substrates, downstream functions, contributions to cell fate and colorectal cancer (CRC) progression remains incomplete.
PURPOSE
The aim of this study was to investigate the effects and mechanisms of naringenin on CRC.
METHODS
The biological and cellular properties of naringenin and its anticancer activity were evaluated in CRC. In addition, the effect of combined treatment with naringenin and 5-fluorouracil on tumor growth in vitro and in vivo was evaluated.
RESULTS
The present study found that naringenin inhibits the proliferation of CRC and promote its apoptosis. Compared with the naringenin group, naringenin combined with 5-fluorouracil had significant effect on inhibiting cell proliferation and promoting its apoptosis. It is showed that naringenin activates AMPK phosphorylation and mitochondrial fusion in CRC. Naringenin combined with 5-fluorouracil significantly reduces cardiotoxicity and liver damage induced by 5-fluorouracil in nude mice bearing subcutaneous CRC tumors, and attenuates colorectal injuries in azoxymethane/DSS dextran sulfate (AOM/DSS)-induced CRC. The combination of these two drugs alters mitochondrial function by increasing reactive oxygen species (ROS) levels and decreasing the mitochondrial membrane potential (MMP), thereby stimulating AMPK/mTOR signaling. Mitochondrial dynamics are thereby regulated by activating the AMPK/p-AMPK pathway, and mitochondrial homeostasis is coordinated through increased mitochondrial fusion and reduced fission to activate apoptosis in cancer cells.
CONCLUSIONS
Our data suggest that naringenin is important for inhibiting CRC proliferation, possibly through the AMPK pathway, to regulate mitochondrial function and induce apoptosis in CRC.
PubMed: 38875812
DOI: 10.1016/j.phymed.2024.155786 -
Frontiers in Chemistry 2024Mitochondria are the energy factories of cells and are important targets for the development of novel tumour treatment strategies owing to their involvement in processes... (Review)
Review
Mitochondria are the energy factories of cells and are important targets for the development of novel tumour treatment strategies owing to their involvement in processes such as apoptosis, oxidative stress, and metabolic programming. Thiosemicarbazone metal complexes target mitochondria and reduce mitochondrial membrane potential. The breakdown of mitochondrial membrane potential is a key event in the early stage of apoptosis, which releases cytochrome C and other pro-apoptotic factors, activates the intracellular apoptotic enzyme cascade, and eventually causes irreversible apoptosis of tumour cells. Thiosemicarbazone metal complexes targeting the mitochondria have recently emerged as potential antitumour agents; therefore, this review describes the structural diversity of thiosemicarbazone metal [Fe(III), Cu(II), Ni(II), Zn(II), Ga(III), Pb(II), Au(III), and Ir(III)] complexes and explores their anti-tumour mechanisms that target mitochondrial pathways.
PubMed: 38873408
DOI: 10.3389/fchem.2024.1424022 -
Bioactive Materials Oct 2024Previous studies have confirmed that intervertebral disc degeneration (IDD) is closely associated with inflammation-induced reactive oxygen species (ROS) and resultant...
Previous studies have confirmed that intervertebral disc degeneration (IDD) is closely associated with inflammation-induced reactive oxygen species (ROS) and resultant cell mitochondrial membrane potential (MMP) decline. Clearance of ROS in an inflammatory environment is essential for breaking the vicious cycle of MMP decline. Additionally, re-energizing the mitochondria damaged in the inflammatory milieu to restore their function, is equally important. Herein, we proposed an interesting concept of mitochondrion-engine equipped with coolant, which enables first to "cool-down" the inflammatory environment, next to restore the MMP, finally to allow cells to regain normal energy metabolism through materials design. As such, we developed a multi-functional composite composed of a reactive oxygen species (ROS)-responsive sodium alginate/gelatin hydrogel infused into a rigid 3D-printed thermoplastic polyurethane (TPU) scaffold. The TPU scaffold was coated with conductive polypyrrole (PPy) to electrophoretically deposit l-arginine, which could upregulate the Mammalian target of rapamycin () pathway, thus increasing MMP and energy metabolism to stimulate extracellular matrix synthesis for IVD repair. While the ROS-responsive hydrogel acting as the "mito-engine coolant" could scavenge the excessive ROS to create a favorable environment for IVD cells recovery. Demonstrated by and evaluations, the mito-engine system markedly promoted the proliferation and collagen synthesis of nucleus pulposus cells while enhancing the mitochondrial respiration and MMP under oxidative stress. Radiological and histological assessments revealed the efficacy of this system in IVD repair. This unique bioinspired design integrated biomaterial science with mitochondrial biology, presents a promising paradigm for IDD treatment.
PubMed: 38873262
DOI: 10.1016/j.bioactmat.2024.05.044 -
Cell Communication and Signaling : CCS Jun 2024Kawasaki disease (KD) is an immune vasculitis of unknown origin, characterized by transient inflammation. The activation of the cGAS-STING pathway, triggered by...
BACKGROUND
Kawasaki disease (KD) is an immune vasculitis of unknown origin, characterized by transient inflammation. The activation of the cGAS-STING pathway, triggered by mitochondrial DNA (mtDNA) release, has been implicated in the onset of KD. However, its specific role in the progression of inflammation during KD's acute phase remains unclear.
METHODS
We measured mtDNA and 2'3'-cGAMP expression in KD patient serum using RT-qPCR and ELISA. A murine model of KD was induced by injecting Lactobacillus casei cell wall extract (LCWE), after which cGAS-STING pathway activation and inflammatory markers were assessed via immunohistochemistry, western blot, and RT-qPCR. Human umbilical vein endothelial cells (HUVECs) were treated with KD serum and modulators of the cGAS-STING pathway for comparative analysis. Mitochondrial function was evaluated using Mitosox staining, mPTP opening was quantified by fluorescence microscopy, and mitochondrial membrane potential (MMP) was determined with JC-1 staining.
RESULTS
KD patient serum exhibited increased mtDNA and 2'3'-cGAMP expression, with elevated levels of pathway-related proteins and inflammatory markers observed in both in vivo and in vitro models. TEM confirmed mitochondrial damage, and further studies demonstrated that inhibition of mPTP opening reduced mtDNA release, abrogated cGAS-STING pathway activation, and mitigated inflammation.
CONCLUSION
These findings indicate that mtDNA released through the mPTP is a critical activator of the cGAS-STING pathway, contributing significantly to KD-associated inflammation. Targeting mtDNA release or the cGAS-STING pathway may offer novel therapeutic approaches for KD management.
Topics: Mucocutaneous Lymph Node Syndrome; DNA, Mitochondrial; Nucleotidyltransferases; Humans; Membrane Proteins; Inflammation; Animals; Mitochondrial Permeability Transition Pore; Signal Transduction; Male; Mice; Human Umbilical Vein Endothelial Cells; Female; Acute Disease; Mice, Inbred C57BL; Child, Preschool
PubMed: 38872145
DOI: 10.1186/s12964-024-01677-9 -
Scientific Reports Jun 2024Barth syndrome (BTHS) is a lethal rare genetic disorder, which results in cardiac dysfunction, severe skeletal muscle weakness, immune issues and growth delay. Mutations...
Barth syndrome (BTHS) is a lethal rare genetic disorder, which results in cardiac dysfunction, severe skeletal muscle weakness, immune issues and growth delay. Mutations in the TAFAZZIN gene, which is responsible for the remodeling of the phospholipid cardiolipin (CL), lead to abnormalities in mitochondrial membrane, including alteration of mature CL acyl composition and the presence of monolysocardiolipin (MLCL). The dramatic increase in the MLCL/CL ratio is the hallmark of patients with BTHS, which is associated with mitochondrial bioenergetics dysfunction and altered membrane ultrastructure. There are currently no specific therapies for BTHS. Here, we showed that cardiac mitochondria isolated from TAFAZZIN knockdown (Taz) mice presented abnormal ultrastructural membrane morphology, accumulation of vacuoles, pro-fission conditions and defective mitophagy. Interestingly, we found that in vivo treatment of Taz mice with a CL-targeted small peptide (named SS-31) was able to restore mitochondrial morphology in tafazzin-deficient heart by affecting specific proteins involved in dynamic process and mitophagy. This agrees with our previous data showing an improvement in mitochondrial respiratory efficiency associated with increased supercomplex organization in Taz mice under the same pharmacological treatment. Taken together our findings confirm the beneficial effect of SS-31 in the amelioration of tafazzin-deficient dysfunctional mitochondria in a BTHS animal model.
Topics: Animals; Barth Syndrome; Mitophagy; Disease Models, Animal; Mice; Acyltransferases; Cardiolipins; Mitochondria, Heart; Transcription Factors; Lysophospholipids; Mice, Knockout; Oligopeptides
PubMed: 38871974
DOI: 10.1038/s41598-024-64368-y