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Theoharides TC. Could SARS-CoV-2 Spike Protein Be Responsible for Long-COVID Syndrome? Mol Neurobiol 2022; 59:1850-1861. [PMID: 35028901 PMCID: PMC8757925 DOI: 10.1007/s12035-021-02696-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/10/2021] [Indexed: 02/06/2023]
Abstract
SARS-CoV-2 infects cells via its spike protein binding to its surface receptor on target cells and results in acute symptoms involving especially the lungs known as COVID-19. However, increasing evidence indicates that many patients develop a chronic condition characterized by fatigue and neuropsychiatric symptoms, termed long-COVID. Most of the vaccines produced so far for COVID-19 direct mammalian cells via either mRNA or an adenovirus vector to express the spike protein, or administer recombinant spike protein, which is recognized by the immune system leading to the production of neutralizing antibodies. Recent publications provide new findings that may help decipher the pathogenesis of long-COVID. One paper reported perivascular inflammation in brains of deceased patients with COVID-19, while others showed that the spike protein could damage the endothelium in an animal model, that it could disrupt an in vitro model of the blood-brain barrier (BBB), and that it can cross the BBB resulting in perivascular inflammation. Moreover, the spike protein appears to share antigenic epitopes with human molecular chaperons resulting in autoimmunity and can activate toll-like receptors (TLRs), leading to release of inflammatory cytokines. Moreover, some antibodies produced against the spike protein may not be neutralizing, but may change its conformation rendering it more likely to bind to its receptor. As a result, one wonders whether the spike protein entering the brain or being expressed by brain cells could activate microglia, alone or together with inflammatory cytokines, since protective antibodies could not cross the BBB, leading to neuro-inflammation and contributing to long-COVID. Hence, there is urgent need to better understand the neurotoxic effects of the spike protein and to consider possible interventions to mitigate spike protein-related detrimental effects to the brain, possibly via use of small natural molecules, especially the flavonoids luteolin and quercetin.
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Affiliation(s)
- Theoharis C Theoharides
- Laboratory of Molecular Immunopharmacology and Drug Discovery, Department of Immunology, Tufts University School of Medicine, 136 Harrison Avenue, Suite 304, Boston, MA, 02111, USA.
- School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, MA, 02111, USA.
- Departments of Internal Medicine and Psychiatry, Tufts University School of Medicine and Tufts Medical Center, Boston, MA, 02111, USA.
- Institute of Neuro-Immune Medicine, Nova Southeastern University, Clearwater, FL, 33759, USA.
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Ney GM, Yang KB, Ng V, Liu L, Zhao M, Kuk W, Alaka L, Sampang L, Ross A, Jones MA, Jin X, McKay LM, Evarts H, Li Q. Oncogenic N-Ras Mitigates Oxidative Stress-Induced Apoptosis of Hematopoietic Stem Cells. Cancer Res 2021; 81:1240-1251. [PMID: 33441311 PMCID: PMC8647627 DOI: 10.1158/0008-5472.can-20-0118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 12/07/2020] [Accepted: 01/12/2021] [Indexed: 11/16/2022]
Abstract
Leukemic relapse is believed to be driven by transformed hematopoietic stem cells (HSC) that harbor oncogenic mutations or have lost tumor suppressor function. Recent comprehensive sequencing studies have shown that mutations predicted to activate Ras signaling are highly prevalent in hematologic malignancies and, notably, in refractory and relapsed cases. To better understand what drives this clinical phenomenon, we expressed oncogenic NrasG12D within the hematopoietic system in mice and interrogated its effects on HSC survival. N-RasG12D conferred a survival benefit to HSCs and progenitors following metabolic and genotoxic stress. This effect was limited to HSCs and early progenitors and was independent of autophagy and cell proliferation. N-RasG12D-mediated HSC survival was not affected by inhibition of canonical Ras effectors such as MEK and PI3K. However, inhibition of the noncanonical Ras effector pathway protein kinase C (PKC) ameliorated the protective effects of N-RasG12D. Mechanistically, N-RasG12D lowered levels of reactive oxygen species (ROS), which correlated with reduced mitochondrial membrane potential and ATP levels. Inhibition of PKC restored the levels of ROS to that of control HSCs and abrogated the protective effects granted by N-RasG12D. Thus, N-RasG12D activation within HSCs promotes cell survival through the mitigation of ROS, and targeting this mechanism may represent a viable strategy to induce apoptosis during malignant transformation of HSCs. SIGNIFICANCE: Targeting oncogenic N-Ras-mediated reduction of ROS in hematopoietic stem cells through inhibition of the noncanonical Ras effector PKC may serve as a novel strategy for treatment of leukemia and other Ras-mutated cancers.
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Affiliation(s)
- Gina M Ney
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan
| | - Kevin B Yang
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Victor Ng
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Lu Liu
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Meiling Zhao
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Wun Kuk
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Lila Alaka
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Leilani Sampang
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Adam Ross
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Morgan A Jones
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Xi Jin
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Laura M McKay
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan
| | - Hadie Evarts
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Qing Li
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan.
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
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Mahameed M, Wilhelm T, Darawshi O, Obiedat A, Tommy WS, Chintha C, Schubert T, Samali A, Chevet E, Eriksson LA, Huber M, Tirosh B. The unfolded protein response modulators GSK2606414 and KIRA6 are potent KIT inhibitors. Cell Death Dis 2019; 10:300. [PMID: 30931942 PMCID: PMC6443726 DOI: 10.1038/s41419-019-1523-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/10/2019] [Accepted: 03/11/2019] [Indexed: 12/17/2022]
Abstract
IRE1, PERK, and ATF6 are the three transducers of the mammalian canonical unfolded protein response (UPR). GSK2606414 is a potent inhibitor of PERK, while KIRA6 inhibits the kinase activity of IRE1. Both molecules are frequently used to probe the biological roles of the UPR in mammalian cells. In a direct binding assay, GSK2606414 bound to the cytoplasmic domain of KIT with dissociation constants (Kd) value of 664 ± 294 nM whereas KIRA6 showed a Kd value of 10.8 ± 2.9 µM. In silico docking studies confirmed a compact interaction of GSK2606414 and KIRA6 with KIT ATP binding pocket. In cultured cells, GSK2606414 inhibited KIT tyrosine kinase activity at nanomolar concentrations and in a PERK-independent manner. Moreover, in contrast to other KIT inhibitors, GSK2606414 enhanced KIT endocytosis and its lysosomal degradation. Although KIRA6 also inhibited KIT at nanomolar concentrations, it did not prompt KIT degradation, and rescued KIT from GSK2606414-mediated degradation. Consistent with KIT inhibition, nanomolar concentrations of GSK2606414 and KIRA6 were sufficient to induce cell death in a KIT signaling-dependent mast cell leukemia cell line. Our data show for the first time that KIT is a shared target for two seemingly unrelated UPR inhibitors at concentrations that overlap with PERK and IRE1 inhibition. Furthermore, these data underscore discrepancies between in vitro binding measurements of kinase inhibitors and inhibition of the tyrosine kinase receptors in living cells.
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Affiliation(s)
- Mohamed Mahameed
- Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Thomas Wilhelm
- Institute of Biochemistry and Molecular Immunology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Odai Darawshi
- Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Akram Obiedat
- Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Weiss-Sadan Tommy
- Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Chetan Chintha
- Apoptosis Research Centre, National University of Ireland Galway, Galway, H91 TK33, Ireland
| | | | - Afshin Samali
- Apoptosis Research Centre, National University of Ireland Galway, Galway, H91 TK33, Ireland
| | - Eric Chevet
- INSERM U1242, Université de Rennes, Rennes, France.,Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France
| | - Leif A Eriksson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göthenburg, Sweden
| | - Michael Huber
- Institute of Biochemistry and Molecular Immunology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Boaz Tirosh
- Institute for Drug Research, The Hebrew University of Jerusalem, Jerusalem, Israel.
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Yessotoxin, a Marine Toxin, Exhibits Anti-Allergic and Anti-Tumoural Activities Inhibiting Melanoma Tumour Growth in a Preclinical Model. PLoS One 2016; 11:e0167572. [PMID: 27973568 PMCID: PMC5156389 DOI: 10.1371/journal.pone.0167572] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 11/15/2016] [Indexed: 01/29/2023] Open
Abstract
Yessotoxins (YTXs) are a group of marine toxins produced by the dinoflagellates Protoceratium reticulatum, Lingulodinium polyedrum and Gonyaulax spinifera. They may have medical interest due to their potential role as anti-allergic but also anti-cancer compounds. However, their biological activities remain poorly characterized. Here, we show that the small molecular compound YTX causes a slight but significant reduction of the ability of mast cells to degranulate. Strikingly, further examination revealed that YTX had a marked and selective cytotoxicity for the RBL-2H3 mast cell line inducing apoptosis, while primary bone marrow derived mast cells were highly resistant. In addition, YTX exhibited strong cytotoxicity against the human B-chronic lymphocytic leukaemia cell line MEC1 and the murine melanoma cell line B16F10. To analyse the potential role of YTX as an anti-cancer drug in vivo we used the well-established B16F10 melanoma preclinical mouse model. Our results demonstrate that a few local application of YTX around established tumours dramatically diminished tumour growth in the absence of any significant toxicity as determined by the absence of weight loss and haematological alterations. Our data support that YTX may have a minor role as an anti-allergic drug, but reveals an important potential for its use as an anti-cancer drug.
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