1
|
Tsao HC, Liao YF, Pratiwi FW, Mou CY, Lin YJ, Pan CY, Chen YT. Zn 2+-Depletion Enhances Lysosome Fission in Cultured Rat Embryonic Cortical Neurons Revealed by a Modified Epifluorescence Microscopic Technique. Microsc Microanal 2021; 27:420-424. [PMID: 33487212 DOI: 10.1017/s1431927620024940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Lysosomes are integration hubs for several signaling pathways, such as autophagy and endocytosis, and also crucial stores of ions, including Zn2+. Lysosomal dysfunction caused by changes in their morphology by fusion and fission processes can result in several pathological disorders. However, the role of Zn2+ in modulating the morphology of lysosomes is unclear. The resolution of conventional epifluorescence microscopy restricts accurate observation of morphological changes of subcellular fluorescence punctum. In this study, we used a modified epifluorescence microscopy to identify the center of a punctum from a series of z-stack images and calculate the morphological changes. We stained primary cultured rat embryonic cortical neurons with FluoZin3, a Zn2+-sensitive fluorescent dye, and Lysotracker, a lysosome-specific marker, to visualize the distribution of Zn2+-enriched vesicles and lysosomes, respectively. Our results revealed that treating neurons with N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine, a cell-permeable Zn2+ chelator, shrank Zn2+-enriched vesicles and lysosomes by up to 25% in an hour. Pretreating the neurons with YM201636, a blocker of lysosome fission, could suppress this shrinkage. These results demonstrate the usefulness of the modified epifluorescence microscopy for investigating the homeostasis of intracellular organelles and related disorders.
Collapse
Affiliation(s)
- Hung-Chun Tsao
- Department of Chemistry, National Taiwan University, Taipei10617, Taiwan
| | - Yi-Feng Liao
- Department of Life Science, National Taiwan University, Taipei10617, Taiwan
- Institute of Physics, Academia Sinica, Taipei11529, Taiwan
| | | | - Chung-Yuan Mou
- Department of Chemistry, National Taiwan University, Taipei10617, Taiwan
| | - Yi-Jhen Lin
- Department of Life Science, National Taiwan University, Taipei10617, Taiwan
| | - Chien-Yuan Pan
- Department of Life Science, National Taiwan University, Taipei10617, Taiwan
| | - Yit-Tsong Chen
- Department of Chemistry, National Taiwan University, Taipei10617, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei10617, Taiwan
| |
Collapse
|
2
|
DoĞan E, DÜzgÜn Z, Yildirim Z, Özdİl B, AktuĞ H, Bozok ÇetİntaŞ V. The effects of PIKfyve inhibitor YM201636 on claudins and malignancy potential of nonsmall cell cancer cells. ACTA ACUST UNITED AC 2021; 45:26-34. [PMID: 33597819 PMCID: PMC7877718 DOI: 10.3906/biy-2010-32] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/22/2020] [Indexed: 11/15/2022]
Abstract
PIKfyve is an evolutionarily conserved lipid and protein kinase enzyme that has pleiotropic cellular functions. The aim of the present study was to investigate the effects of phosphatidylinositol-3-phosphate 5-kinase (PIKfyve) inhibitor, YM201636, on nonsmall cell lung cancer (NSCLC) cells growth, tumorigenicity, and claudin (CLDN) expressions. Three NSCLC cell lines (Calu-1, H1299 and HCC827) were used to compare the effects of YM201636. Cytotoxic effects of YM201636 were analysed using XTT assay. Malignancy potential of cells assesses with wound healing and soft agar colony-forming assays. mRNA and protein expressions of claudins were analysed by qRT-PCR and immunofluorescence staining. Our results revealed that YM201636 inhibited the proliferation and malignancy potential of Calu-1, H1299, and HCC827 cells in a dose-dependent manner. After YM201636 treatment CLDN1, -3 and -5 expressions increased significantly in HCC827 cells. CLDN3 and -5 expressions also significantly increased in Calu1 cell line. YM201636 treatment significantly reduced the CLDN1 and increased the CLDN5 expression in H1299 cells. Immunofluorescence staining of CLDN1, -3 and -5 proteins showed a significant increase after YM201636 treatment. Besides, YM201636 induced EGFR mRNA expression in all NSCLC cell lines. Our results have shown that YM201636 inhibits tumorigenicity of NSCLC cells. Furthermore, estimated glomerular filtration rate (EGFR) pathway is important signalling involved in the regulation of claudins. Understanding the mechanisms of PIKfyve inhibitors may improve cancer treatment particularly for EGFR overactivated NSCLC.
Collapse
Affiliation(s)
- Eda DoĞan
- Department of Medical Biology, Faculty of Medicine, Ege University, İzmir Turkey
| | - Zekeriya DÜzgÜn
- Department of Medical Biology, Faculty of Medicine, Giresun University, Giresun Turkey
| | - Zafer Yildirim
- Department of Medical Biology, Faculty of Medicine, Ege University, İzmir Turkey
| | - Berrin Özdİl
- Department of Histology and Embryology, Faculty of Medicine, Ege University, İzmir Turkey
| | - Hüseyin AktuĞ
- Department of Histology and Embryology, Faculty of Medicine, Ege University, İzmir Turkey
| | | |
Collapse
|
3
|
Hirano T, Stecker K, Munnik T, Xu H, Sato MH. Visualization of Phosphatidylinositol 3,5-Bisphosphate Dynamics by a Tandem ML1N-Based Fluorescent Protein Probe in Arabidopsis. Plant Cell Physiol 2017; 58:1185-1195. [PMID: 28158631 PMCID: PMC5921506 DOI: 10.1093/pcp/pcx011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 01/13/2017] [Indexed: 05/24/2023]
Abstract
Phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2] is a low-abundance phospholipid known to be associated with a wide variety of physiological functions in plants. However, the localization and dynamics of PI(3,5)P2 in plant cells remain largely unknown, partially due to the lack of an effective fluorescent probe. Using Arabidopsis transgenic plant expressing the PI(3,5)P2-labeling fluorescent probe (tagRFP-ML1N*2) developed based on a tandem repeat of the cytosolic phosphoinositide-interacting domain (ML1N) of the mammalian lysosomal transient receptor potential cation channel, Mucolipin 1 (TRPML1), here we show that PI(3,5)P2 is predominantly localized on the limited membranes of the FAB1- and SNX1-positive late endosomes, but rarely localized on the membranes of plant vacuoles or trans-Golgi network/early endosomes of cortical cells of the root differentiation zone. The late endosomal localization of tagRFP-ML1N*2 is reduced or abolished by pharmacological inhibition or genetic knockdown of expression of genes encoding PI(3,5)P2-synthesizing enzymes, FAB1A/B, but markedly increased with FAB1A overexpression. Notably, reactive oxygen species (ROS) significantly increase late endosomal levels of PI(3,5)P2. Thus, tandem ML1N-based PI(3,5)P2 probes can reliably monitor intracellular dynamics of PI(3,5)P2 in Arabidopsis cells with less binding activity to other endomembrane organelles.
Collapse
Affiliation(s)
- Tomoko Hirano
- Laboratory of Cellular Dynamics, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo-nakaragi-cho, Sakyo-ku, Kyoto, 606-8522 Japan
| | - Kelly Stecker
- Biotechnology Center, University of Wisconsin, Madison, WI 53706, USA
| | - Teun Munnik
- Section of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science park 904, 1098 XH Amsterdam 94216, The Netherlands
| | - Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Masa H. Sato
- Laboratory of Cellular Dynamics, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamo-nakaragi-cho, Sakyo-ku, Kyoto, 606-8522 Japan
| |
Collapse
|
4
|
Hirano T, Munnik T, Sato MH. Inhibition of phosphatidylinositol 3,5-bisphosphate production has pleiotropic effects on various membrane trafficking routes in Arabidopsis. Plant Cell Physiol 2017; 58:120-129. [PMID: 27803131 DOI: 10.1093/pcp/pcw164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
Phosphoinositides play an important role in various membrane trafficking events in eukaryotes. One of them, however, phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2], has not been studied widely in plants. Using a combination of fluorescent reporter proteins and the PI(3,5)P2-specific inhibitor YM202636, here we demonstrated that in Arabidopsis thaliana, PI(3,5)P2 affects various membrane trafficking events, mostly in the post-Golgi routes. We found that YM201636 treatment effectively reduced PI(3,5)P2 concentration not only in the wild type but also in FAB1A-overexpressing Arabidopsis plants. In particular, reduced PI(3,5)P2 levels caused abnormal membrane dynamics of plasma membrane proteins, AUX1 and BOR1, with different trafficking patterns. Secretion and morphological characteristics of late endosomes and vacuoles were also affected by the decreased PI(3,5)P2 production. These pleiotropic defects in the post-Golgi trafficking events were caused by the inhibition of PI(3,5)P2 production. This effect is probably mediated by the inhibition of maturation of FAB1-positive late endosomes, thereby impairing late endosome function. In conclusion, our results imply that in Arabidopsis, late endosomes are involved in multiple post-Golgi membrane trafficking routes including not only vacuolar trafficking and endocytosis but also secretion.
Collapse
Affiliation(s)
- Tomoko Hirano
- Laboratory of Cellular Dynamics, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Teun Munnik
- Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Masa H Sato
- Laboratory of Cellular Dynamics, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| |
Collapse
|
5
|
Compton LM, Ikonomov OC, Sbrissa D, Garg P, Shisheva A. Active vacuolar H+ ATPase and functional cycle of Rab5 are required for the vacuolation defect triggered by PtdIns(3,5)P2 loss under PIKfyve or Vps34 deficiency. Am J Physiol Cell Physiol 2016; 311:C366-77. [PMID: 27335171 DOI: 10.1152/ajpcell.00104.2016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 06/17/2016] [Indexed: 01/12/2023]
Abstract
The two evolutionarily conserved mammalian lipid kinases Vps34 and PIKfyve are involved in an important physiological relationship, whereby the former produces phosphatidylinositol (PtdIns) 3P that is used as a substrate for PtdIns(3,5)P2 synthesis by the latter. Reduced production of PtdIns(3,5)P2 in proliferating mammalian cells is phenotypically manifested by the formation of multiple translucent cytoplasmic vacuoles, readily rescued upon exogenous delivery of PtdIns(3,5)P2 or overproduction of PIKfyve. Although the aberrant vacuolation phenomenon has been frequently used as a sensitive functional measure of localized PtdIns(3,5)P2 reduction, cellular factors governing the appearance of cytoplasmic vacuoles under PtdIns3P-PtdIns(3,5)P2 loss remain elusive. To gain further mechanistic insight about the vacuolation process following PtdIns(3,5)P2 reduction, in this study we sought for cellular mechanisms required for manifestation of the aberrant endomembrane vacuoles triggered by PIKfyve or Vps34 dysfunction. The latter was achieved by various means such as pharmacological inhibition, gene disruption, or dominant-interference in several proliferating mammalian cell types. We report here that inhibition of V-ATPase with bafilomycin A1 as well as inactivation of the GTP-GDP cycle of Rab5a GTPase phenotypically rescued or completely precluded the cytoplasmic vacuolization despite the continued presence of inactivated PIKfyve or Vps34. Bafilomycin A1 also restored the aberrant EEA1-positive endosomes, enlarged upon short PIKfyve inhibition with YM201636. Together, our work identifies for the first time that factors such as active V-ATPase or functional Rab5a cycle are acting coincidentally with the PtdIns(3,5)P2 reduction in triggering formation of aberrant cytoplasmic vacuoles under PIKfyve or Vps34 dysfunction.
Collapse
Affiliation(s)
- Lauren M Compton
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - Ognian C Ikonomov
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - Diego Sbrissa
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| | - Puneet Garg
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan; and
| |
Collapse
|