Vol.46 No.9, September 30, 2023 Article TypeJournal ClubMinireviewResearch Article

• Minireview 2023-09-30

  0 232 77

  Updates on the Immune Cell Basis of Hepatic Ischemia-Reperfusion Injury

  Mi Jeong Heo , Ji Ho Suh , Kyle L. Poulsen , Cynthia Ju , and Kang Ho Kim

  Mol. Cells 2023; 46(9): 527-534 https://doi.org/10.14348/molcells.2023.0099

  

  

  Abstract

  Full Text PubReader Cite Share

  Abstract : Liver ischemia-reperfusion injury (IRI) is the main cause of organ dysfunction and failure after liver surgeries including organ transplantation. The mechanism of liver IRI is complex and numerous signals are involved but cellular metabolic disturbances, oxidative stress, and inflammation are considered the major contributors to liver IRI. In addition, the activation of inflammatory signals exacerbates liver IRI by recruiting macrophages, dendritic cells, and neutrophils, and activating NK cells, NKT cells, and cytotoxic T cells. Technological advances enable us to understand the role of specific immune cells during liver IRI. Accordingly, therapeutic strategies to prevent or treat liver IRI have been proposed but no definitive and effective therapies exist yet. This review summarizes the current update on the immune cell functions and discusses therapeutic potentials in liver IRI. A better understanding of this complex and highly dynamic process may allow for the development of innovative therapeutic approaches and optimize patient outcomes.

• Journal Club 2023-09-30

  0 129 23

  Unveiling Nature’s Nitrogen-Fixing Secrets

  Wonchull Kang

  Mol. Cells 2023; 46(9): 535-537 https://doi.org/10.14348/molcells.2023.0086

  

  

  Full Text PubReader Cite Share

• Research Article 2023-09-30

  0 254 68

  Copper Oxide Spike Grids for Enhanced Solution Transfer in Cryogenic Electron Microscopy

  Dukwon Lee , Hansol Lee , Jinwook Lee , Soung-Hun Roh , and Nam-Chul Ha

  Mol. Cells 2023; 46(9): 538-544 https://doi.org/10.14348/molcells.2023.0058

  

  

  Abstract

  Full Text PubReader Cite Share

  Abstract : The formation of uniform vitreous ice is a crucial step in the preparation of samples for cryogenic electron microscopy (cryo-EM). Despite the rapid technological progress in EM, controlling the thickness of vitreous ice on sample grids with reproducibility remains a major obstacle to obtaining high-quality data in cryo-EM imaging. The commonly employed classical blotting process faces the problem of excess water that cannot be absorbed by the filter paper, resulting in the formation of thick and heterogeneous ice. In this study, we propose a novel approach that combines the recently developed nanowire self-wicking technique with the classical blotting method to effectively control the thickness and homogeneity of vitrified ice. With simple procedures, we generated a copper oxide spike (COS) grid by inducing COSs on commercially available copper grids, which can effectively remove excess water during the blotting procedure without damaging the holey carbon membrane. The ice thickness could be controlled with good reproducibility compared to non-oxidized grids. Incorporated into other EM techniques, our new modification method is an effective option for obtaining high-quality data during cryo-EM imaging.

• Research Article 2023-09-30

  0 400 119

  Purification and Characterization of Mitochondrial Mg²⁺-Independent Sphingomyelinase from Rat Brain

  Jong Min Choi , Yongwei Piao , Kyong Hoon Ahn , Seok Kyun Kim , Jong Hoon Won , Jae Hong Lee , Ji Min Jang , In Chul Shin , Zhicheng Fu , Sung Yun Jung , Eui Man Jeong , and Dae Kyong Kim

  Mol. Cells 2023; 46(9): 545-557 https://doi.org/10.14348/molcells.2023.0074

  

  

  Abstract

  Full Text PubReader Cite Share

  Abstract : Sphingomyelinase (SMase) catalyzes ceramide production from sphingomyelin. Ceramides are critical in cellular responses such as apoptosis. They enhance mitochondrial outer membrane permeabilization (MOMP) through self-assembly in the mitochondrial outer membrane to form channels that release cytochrome c from intermembrane space (IMS) into the cytosol, triggering caspase-9 activation. However, the SMase involved in MOMP is yet to be identified. Here, we identified a mitochondrial Mg²⁺-independent SMase (mt-iSMase) from rat brain, which was purified 6,130-fold using a Percoll gradient, pulled down with biotinylated sphingomyelin, and subjected to Mono Q anion exchange. A single peak of mt-iSMase activity was eluted at a molecular mass of approximately 65 kDa using Superose 6 gel filtration. The purified enzyme showed optimal activity at pH of 6.5 and was inhibited by dithiothreitol and Mg²⁺, Mn²⁺, N²⁺, Cu²⁺, Zn²⁺, Fe²⁺, and Fe³⁺ ions. It was also inhibited by GW4869, which is a non-competitive inhibitor of Mg²⁺-dependent neutral SMase 2 (encoded by SMPD3), that protects against cytochrome c release-mediated cell death. Subfractionation experiments showed that mt-iSMase localizes in the IMS of the mitochondria, implying that mt-iSMase may play a critical role in generating ceramides for MOMP, cytochrome c release, and apoptosis. These data suggest that the purified enzyme in this study is a novel SMase.

• Research Article 2023-09-30

  0 321 162

  Recombinant Human HAPLN1 Mitigates Pulmonary Emphysema by Increasing TGF-β Receptor I and Sirtuins Levels in Human Alveolar Epithelial Cells

  Yongwei Piao , So Yoon Yun , Zhicheng Fu , Ji Min Jang , Moon Jung Back , Ha Hyung Kim , and Dae Kyong Kim

  Mol. Cells 2023; 46(9): 558-572 https://doi.org/10.14348/molcells.2023.0097

  

  

  Abstract

  Full Text PubReader Cite Share

  Abstract : Chronic obstructive pulmonary disease (COPD) will be the third leading cause of death worldwide by 2030. One of its components, emphysema, has been defined as a lung disease that irreversibly damages the lungs’ alveoli. Treatment is currently unavailable for emphysema symptoms and complete cure of the disease. Hyaluronan (HA) and proteoglycan link protein 1 (HAPLN1), an HA-binding protein linking HA in the extracellular matrix to stabilize the proteoglycan structure, forms a bulky hydrogel-like aggregate. Studies on the biological role of the full-length HAPLN1, a simple structure-stabilizing protein, are limited. Here, we demonstrated for the first time that treating human alveolar epithelial type 2 cells with recombinant human HAPLN1 (rhHAPLN1) increased TGF-β receptor 1 (TGF-β RI) protein levels, but not TGF-β RII, in a CD44-dependent manner with concurrent enhancement of the phosphorylated Smad3 (p-Smad3), but not p-Smad2, upon TGF-β1 stimulation. Furthermore, rhHAPLN1 significantly increased sirtuins levels (i.e., SIRT1/2/6) without TGF-β1 and inhibited acetylated p300 levels that were increased by TGF-β1. rhHAPLN1 is crucial in regulating cellular senescence, including p53, p21, and p16, and inflammation markers such as p-NF-κB and Nrf2. Both senile emphysema mouse model induced via intraperitoneal rhHAPLN1 injections and porcine pancreatic elastase (PPE)-induced COPD mouse model generated via rhHAPLN1-containing aerosols inhalations showed a significantly potent efficacy in reducing alveolar spaces enlargement. Preclinical trials are underway to investigate the effects of inhaled rhHAPLN1-containing aerosols on several COPD animal models.