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Srivatsav AT, Kapoor S. Biophysical Interaction Landscape of Mycobacterial Mycolic Acids and Phenolic Glycolipids with Host Macrophage Membranes. ACS APPLIED BIO MATERIALS 2023; 6:5555-5562. [PMID: 38015441 DOI: 10.1021/acsabm.3c00748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Lipidic adjuvant formulations consisting of immunomodulatory mycobacterial cell wall lipids interact with host cells following administration. The impact of this cross-talk on the host membrane's structure and function is rarely given enough consideration but is imperative to rule out nonspecific perturbation underlying the adjuvant. In this work, we investigated changes in the plasma membranes of live mammalian cells after exposure to mycobacterial mycolic acid (MA) and phenolic glycolipids, two strong candidates for lipidic adjuvant therapy. We found that phenolic glycolipid 1 softened the plasma membrane, lowering membrane tension and stiffness, but MA did not significantly change the membrane characteristics. Further, phenolic glycolipid 1 had a fluidizing impact on the host plasma membrane, increasing the fluidity and the abundance of fluid-ordered-disordered coexisting lipid domains. Notably, lipid diffusion was not impacted. Overall, MA and, to a lesser extent, phenolic glycolipid 1, due to minor disruption of host cell membranes, may serve as appropriate lipids in adjuvant formulations.
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Affiliation(s)
- Aswin T Srivatsav
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Shobhna Kapoor
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
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Li A, Han X, Deng L, Wang X. Mechanical properties of tunneling nanotube and its mechanical stability in human embryonic kidney cells. Front Cell Dev Biol 2022; 10:955676. [PMID: 36238686 PMCID: PMC9551289 DOI: 10.3389/fcell.2022.955676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 09/13/2022] [Indexed: 11/28/2022] Open
Abstract
Tunneling nanotubes (TNTs) are thin membrane tubular structures that interconnect physically separated cells. Growing evidence indicates that TNTs play unique roles in various diseases by facilitating intercellular transfer of signaling and organelles, suggesting TNTs as a potential target for disease treatment. The efficiency of TNT-dependent communication is largely determined by the number of TNTs between cells. Though TNTs are physically fragile structures, the mechanical properties of TNTs and the determinants of their mechanical stability are still unclear. Here, using atomic force microscope (AFM) and microfluidic techniques, we investigated the mechanical behavior and abundance of TNTs in human embryonic kidney (HEK293) cells upon the application of forces. AFM measurements demonstrate that TNTs are elastic structures with an apparent spring constant of 79.1 ± 16.2 pN/μm. The stiffness and membrane tension of TNTs increase by length. TNTs that elongate slower than 0.5 μm/min display higher mechanical stability, due to the growth rate of F-actin inside TNTs being limited at 0.26 μm/min. Importantly, by disturbing the cytoskeleton, membrane, or adhesion proteins of TNTs, we found that F-actin and cadherin connection dominantly determines the tensile strength and flexural strength of TNTs respectively. It may provide new clues for screening TNT-interfering drugs that alter the stability of TNTs.
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Affiliation(s)
| | | | | | - Xiang Wang
- *Correspondence: Linhong Deng, ; Xiang Wang,
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Zhang X, Kang R, Liu Y, Yan Z, Xu Y, Yue T. From reversible to irreversible: When the membrane nanotube pearling is coupled with phase separation. Colloids Surf B Biointerfaces 2021; 209:112160. [PMID: 34736219 DOI: 10.1016/j.colsurfb.2021.112160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/17/2021] [Accepted: 10/07/2021] [Indexed: 12/11/2022]
Abstract
Membrane nanotubes, which are ubiquitous in biology and act as channels maintaining transport between different cells and organelles, readily undergo pearling in response to external stimuli. Membrane nanotube pearling involves generation of heterogeneous curvature coupled with redistribution of membrane components that may interfere with the shape recovery of pearled nanotubes. However, the mechanism underlying such delicate process remains unclear and difficult to study at the molecular scale in vivo. By means of molecular dynamics simulation, here we investigate pearling of multi-component membrane nanotubes and reversibility through manipulating system temperature and osmotic pressure. With the equilibrium shape of membrane nanotubes controlled by the osmotic pressure, our results demonstrate that the process of membrane nanotube pearling can be reversible or irreversible, depending on the phase segregation state. For the pearled nanotube releasing high surface energy, different lipid components redistribute along the tube axial direction. Lipids with unsaturated tails prefer gathering at the high-curvature shrinking region, whereas the swelling region is constituted by saturated lipids forming the liquid-ordered phase of a higher bending rigidity. Such curvature sensitive phase segregation minimizes the system free energy by reducing both the membrane bending energy and line tension at the phase boundary. As such, the pearled nanotube fails to recover its shape upon retracting stimuli, suggesting irreversibility of the membrane nanotube pearling coupled with phase separation. Given importance of membrane nanotube pearling in various cellular activities, these results provide a new mechanism of controlling equilibrium shapes of membrane nanotubes in complex cellular environment.
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Affiliation(s)
- Xiaoyang Zhang
- College of Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Runshan Kang
- College of Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Yingjie Liu
- Institute of Coastal Environmental Pollution Control, Key Laboratory of Marine Environment and Ecology, Ministry of Education, Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao 266100, China
| | - Zengshuai Yan
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
| | - Yan Xu
- College of Electronic Engineering and Automation, Shandong University of Science and Technology, Qingdao 266590, China
| | - Tongtao Yue
- Institute of Coastal Environmental Pollution Control, Key Laboratory of Marine Environment and Ecology, Ministry of Education, Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
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Shao X, Sørensen MH, Xia X, Fang C, Hui TH, Chang RCC, Chu Z, Lin Y. Beading of injured axons driven by tension- and adhesion-regulated membrane shape instability. J R Soc Interface 2020; 17:20200331. [PMCID: PMC7423423 DOI: 10.1098/rsif.2020.0331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/13/2020] [Indexed: 08/14/2023] Open
Abstract
The formation of multiple beads along an injured axon will lead to blockage of axonal transport and eventually neuron death, and this has been widely recognized as a hallmark of nervous system degeneration. Nevertheless, the underlying mechanisms remain poorly understood. Here, we report a combined experimental and theoretical study to reveal key factors governing axon beading. Specifically, by transecting well-developed axons with a sharp atomic force microscope probe, significant beading of the axons was triggered. We showed that adhesion was not required for beading to occur, although when present strong axon–substrate attachments seemed to set the locations for bead formation. In addition, the beading wavelength, representing the average distance between beads, was found to correlate with the size and cytoskeleton integrity of axon, with a thinner axon or a disrupted actin cytoskeleton both leading to a shorter beading wavelength. A model was also developed to explain these observations which suggest that axon beading originates from the shape instability of the membrane and is driven by the release of work done by axonal tension as well as the reduction of membrane surface energy. The beading wavelength predicted from this theory was in good agreement with our experiments under various conditions. By elucidating the essential physics behind axon beading, the current study could enhance our understanding of how axonal injury and neurodegeneration progress as well as provide insights for the development of possible treatment strategies.
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Affiliation(s)
- Xueying Shao
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, People's Republic of China
| | - Maja Højvang Sørensen
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Xingyu Xia
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, People's Republic of China
| | - Chao Fang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, People's Republic of China
| | - Tsz Hin Hui
- Department of Electrical and Electronic Engineering, Joint Appointment with School of Biomedical Sciences, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Raymond Chuen Chung Chang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Zhiqin Chu
- Department of Electrical and Electronic Engineering, Joint Appointment with School of Biomedical Sciences, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Yuan Lin
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, People's Republic of China
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Li S, Yan Z, Huang F, Zhang X, Yue T. How a lipid bilayer membrane responds to an oscillating nanoparticle: Promoted membrane undulation and directional wave propagation. Colloids Surf B Biointerfaces 2019; 187:110651. [PMID: 31784121 DOI: 10.1016/j.colsurfb.2019.110651] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/15/2019] [Accepted: 11/16/2019] [Indexed: 01/14/2023]
Abstract
Mechanical forces acting on a plasma membrane are of essential importance to cellular functioning via inducing delicate change of the membrane shape with the underlying mechanism yet to be elucidated. Here, we introduce an oscillating nanoparticle (NP) interaction with a lipid bilayer membrane, using the coarse-grained simulation to investigate the dynamic membrane response to constrained mechanical stimulation, which is ubiquitous in biology. Our results demonstrate that, the membrane responds to an oscillating NP by generating nanoscale undulation waves, which immediately propagate through the membrane. In dynamics, propagation of the generated membrane undulation waves always starts from flattening of the region where the NP locates, thus producing a lateral force to propel the waves away from the point of stimulation. The speed of membrane undulation wave propagation is proportional to that of NP oscillation and accelerated by increasing the integral membrane surface tension, suggesting that both the membrane bending and stretching contribute to the energy driving the unique response of membrane undulation wave propagation.
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Affiliation(s)
- Shixin Li
- State Key Laboratory of Heavy Oil Processing, Center for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, China
| | - Zengshuai Yan
- State Key Laboratory of Heavy Oil Processing, Center for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, China
| | - Fang Huang
- State Key Laboratory of Heavy Oil Processing, Center for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, China
| | - Xianren Zhang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Tongtao Yue
- State Key Laboratory of Heavy Oil Processing, Center for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, China.
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