bims-mitlys Biomed News
on Mitochondria and Lysosomes
Issue of 2021‒07‒18
four papers selected by
Nicoletta Plotegher
University of Padua

  1. Food Chem Toxicol. 2021 Jul 07. pii: S0278-6915(21)00421-X. [Epub ahead of print]155 112388
      Aluminum (Al), as a common environmental pollutant, causes osteoblast (OB) dysfunction and then leads to Al-related bone diseases (ARBD). One of the mechanisms of ARBD is oxidative stress, which leads to an increase in the production of reactive oxygen species (ROS). ROS can induce mitochondrial damage, thereby inducing mitophagy and apoptosis. But whether mitophagy and apoptosis mediated by ROS, and the role of ROS in AlCl3-induced MC3T3-E1 cell dysfunction is still unclear. In this study, MC3T3-E1 cells used 0 mM Al (control group), 2 mM Al (Al group), 5 mM N-acetyl cysteine (NAC) (NAC group), 2 mM Al and 5 mM NAC (Al + NAC group) for 24 h. We found AlCl3-induced MC3T3-E1 cell dysfunction accompanied by oxidative stress, apoptosis, and mitophagy. While NAC, a ROS scavenger treatment, restored cell function and alleviated the mitophagy and apoptosis. These results suggested that mitophagy and apoptosis mediated by ROS participate in AlCl3-induced MC3T3-E1 cell dysfunction.
    Keywords:  Aluminum; Apoptosis; MC3T3-E1; Mitophagy; ROS
  2. Inflamm Res. 2021 Jul 10.
      BACKGROUND: Multiple organ failure (MOF) is the main cause of early death in septic shock. Lungs are among the organs that are affected in MOF, resulting in acute lung injury. Inflammation is an important factor that causes immune cell dysfunction in the pathogenesis of sepsis. Autophagy is involved in the process of inflammation and also occurs in response to cell and tissue injury in several diseases. We previously demonstrated that hydrogen alleviated the inflammation-induced cell injury and organ damage in septic mice.AIM: The focus of the present study was to elucidate whether mitophagy mediates the inflammatory response or oxidative injury in sepsis in vitro and in vivo. Furthermore, we evaluated the role of mitophagy in the protective effects of hydrogen against cell injury or organ dysfunction in sepsis.
    METHOD: RAW 264.7 macrophages induced by lipopolysaccharide (LPS) were used as an in vitro model for inflammation, and cecal ligation and puncture (CLP)-induced acute lung injury mice were used as an in vivo model for sepsis. The key protein associated with mitophagy, PTEN-induced putative kinase 1 (PINK1), was knocked down by PINK1 shRNA transfection in RAW 264.7 macrophages or mice.
    RESULTS: Hydrogen ameliorated cell injury and enhanced mitophagy in macrophages stimulated by LPS. PINK1 was required for the mitigation of the cell impairment in LPS-stimulated macrophages by hydrogen treatment. PINK1 knockdown abrogated the beneficial effects of hydrogen on mitophagy in LPS-stimulated macrophages. Hydrogen inhibited acute lung injury in CLP mice via activation of PINK1-mediated mitophagy.
    CONCLUSION: These results suggest that PINK1-mediated mitophagy plays a key role in the protective effects of hydrogen against cell injury in LPS-induced inflammation and CLP-induced acute lung injury.
    Keywords:  Hydrogen; Mitophagy; PINK1; Sepsis
  3. Free Radic Biol Med. 2021 Jul 08. pii: S0891-5849(21)00412-3. [Epub ahead of print]
      Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by memory loss and multiple cognitive impairments. AD is marked by multiple cellular changes, including deregulation of microRNAs, activation of glia and astrocytes, hormonal imbalance, defective mitophagy, synaptic degeneration, in addition to extracellular neuritic amyloid-beta (Aβ) plaques, phosphorylated tau (P-tau), and intracellular neurofibrillary tangles (NFTs). Recent research in AD revealed that defective synaptic mitophagy leads to synaptic degeneration and cognitive dysfunction in AD neurons. Our critical analyses of mitochondria and Aβ and P-tau revealed that increased levels of Aβ and P-Tau, and abnormal interactions between Aβ and Drp1, P-Tau and Drp1 induced increased mitochondrial fragmentation and proliferation of dysfunctional mitochondria in AD neurons and depleted Parkin and PINK1 levels. These events ultimately lead to impaired clearance of dead and/or dying mitochondria in AD neurons. The purpose of our article is to highlight the recent research on mitochondria and synapses in relation to Aβ and P-tau, focusing on recent developments.
    Keywords:  Alzheimer's disease; Amyloid beta; Amyloid precursor protein; Autophagy; Mitophagy; Oxidative phosphorylation; Phosphorylated tau
  4. Cancer Lett. 2021 Jul 13. pii: S0304-3835(21)00347-5. [Epub ahead of print]
      Radiotherapy is a standard and conventional treatment strategy for nasopharyngeal carcinoma (NPC); however, radioresistance remains refractory to clinical outcomes. Understanding the molecular mechanism of radioresistance is crucial for advancing the efficacy of radiotherapy and improving the prognosis of NPC. In this study, β-lactamase-like-protein 2 (LACTB2) was identified as a potential biomarker for radioresistance using tandem mass tag proteomic analysis of NPC cells, gene chip analysis of NPC tissues, and differential gene analysis between NPC and normal nasopharyngeal tissues from the Gene Expression Omnibus database GSE68799. Meanwhile, LACTB2 levels were elevated in the serum of patients with NPC after radiotherapy. Inhibiting LACTB2 levels and mitophagy can sensitize NPC cells to ionizing radiation. In NPC cells, LACTB2 was augmented at the transcription and protein levels after radiation rather than nucleus-cytoplasm-mitochondria transposition to activate PTEN-induced kinase 1 (PINK1) and mitophagy. In addition, LACTB2 was first authenticated to co-locate with PINK1 by interacting with its N-terminal domain. Together, our findings indicate that overexpressed LACTB2 provoked PINK1-dependent mitophagy to promote radioresistance and thus might serve as a prognostic biomarker for NPC radiotherapy.
    Keywords:  Autophagy; LACTB2; Mitochondria; Nasopharyngeal carcinoma; Radiosensitivity