1
|
Fink A, Fazliev S, Abele T, Spatz JP, Göpfrich K, Cavalcanti-Adam EA. Membrane localization of actin filaments stabilizes giant unilamellar vesicles against external deforming forces. Eur J Cell Biol 2024; 103:151428. [PMID: 38850712 DOI: 10.1016/j.ejcb.2024.151428] [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] [Received: 06/28/2023] [Revised: 05/25/2024] [Accepted: 06/03/2024] [Indexed: 06/10/2024] Open
Abstract
Actin organization is crucial for establishing cell polarity, which influences processes such as directed cell motility and division. Despite its critical role in living organisms, achieving similar polarity in synthetic cells remains challenging. In this study, we employ a bottom-up approach to investigate how molecular crowders facilitate the formation of cortex-like actin networks and how these networks localize and organize based on membrane shape. Using giant unilamellar vesicles (GUVs) as models for cell membranes, we show that actin filaments can arrange along the membrane to form cortex-like structures. Notably, this organization is achieved using only actin and crowders as a minimal set of components. We utilize surface micropatterning to examine actin filament organization in deformed GUVs adhered to various pattern shapes. Our findings indicate that at the periphery of spherical GUVs, actin bundles align along the membrane. However, in highly curved regions of adhered GUVs, actin bundles avoid crossing the highly curved edges perpendicular to the adhesion site and instead remain in the lower curved regions by aligning parallel to the micropatterned surface. Furthermore, the actin bundles increase the stiffness of the GUVs, effectively counteracting strong deformations when GUVs adhere to micropatterns. This finding is corroborated by real-time deformability cytometry on GUVs with synthetic actin cortices. By precisely manipulating the shape of GUVs, our study provides a minimal system to investigate the interplay between actin structures and the membrane. Our findings provide insights into the spatial organization of actin structures within crowded environments, specifically inside GUVs that resemble the size and shape of cells. This study advances our understanding of actin network organization and functionality within cell-sized compartments.
Collapse
Affiliation(s)
- Andreas Fink
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg 69120, Germany
| | - Sunnatullo Fazliev
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg 69120, Germany
| | - Tobias Abele
- Biophysical Engineering Group, Center for Molecular Biology of Heidelberg University (ZMBH) Heidelberg University, Im Neuenheimer Feld 329, Heidelberg 69120, Germany
| | - Joachim P Spatz
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg 69120, Germany
| | - Kerstin Göpfrich
- Biophysical Engineering Group, Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg 69120, Germany; Biophysical Engineering Group, Center for Molecular Biology of Heidelberg University (ZMBH) Heidelberg University, Im Neuenheimer Feld 329, Heidelberg 69120, Germany
| | - Elisabetta Ada Cavalcanti-Adam
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg 69120, Germany; Cellular Biomechanics, University of Bayreuth, Universitätsstraße 30, Bayreuth 95447, Germany.
| |
Collapse
|
2
|
Kuhn TB, Minamide LS, Tahtamouni LH, Alderfer SA, Walsh KP, Shaw AE, Yanouri O, Haigler HJ, Ruff MR, Bamburg JR. Chemokine Receptor Antagonists Prevent and Reverse Cofilin-Actin Rod Pathology and Protect Synapses in Cultured Rodent and Human iPSC-Derived Neurons. Biomedicines 2024; 12:93. [PMID: 38255199 PMCID: PMC10813319 DOI: 10.3390/biomedicines12010093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/20/2023] [Accepted: 12/26/2023] [Indexed: 01/24/2024] Open
Abstract
Synapse loss is the principal cause of cognitive decline in Alzheimer's disease (AD) and related disorders (ADRD). Synapse development depends on the intricate dynamics of the neuronal cytoskeleton. Cofilin, the major protein regulating actin dynamics, can be sequestered into cofilactin rods, intra-neurite bundles of cofilin-saturated actin filaments that can disrupt vesicular trafficking and cause synaptic loss. Rods are a brain pathology in human AD and mouse models of AD and ADRD. Eliminating rods is the focus of this paper. One pathway for rod formation is triggered in ~20% of rodent hippocampal neurons by disease-related factors (e.g., soluble oligomers of Amyloid-β (Aβ)) and requires cellular prion protein (PrPC), active NADPH oxidase (NOX), and cytokine/chemokine receptors (CCRs). FDA-approved antagonists of CXCR4 and CCR5 inhibit Aβ-induced rods in both rodent and human neurons with effective concentrations for 50% rod reduction (EC50) of 1-10 nM. Remarkably, two D-amino acid receptor-active peptides (RAP-103 and RAP-310) inhibit Aβ-induced rods with an EC50 of ~1 pM in mouse neurons and ~0.1 pM in human neurons. These peptides are analogs of D-Ala-Peptide T-Amide (DAPTA) and share a pentapeptide sequence (TTNYT) antagonistic to several CCR-dependent responses. RAP-103 does not inhibit neuritogenesis or outgrowth even at 1 µM, >106-fold above its EC50. N-terminal methylation, or D-Thr to D-Ser substitution, decreases the rod-inhibiting potency of RAP-103 by 103-fold, suggesting high target specificity. Neither RAP peptide inhibits neuronal rod formation induced by excitotoxic glutamate, but both inhibit rods induced in human neurons by several PrPC/NOX pathway activators (Aβ, HIV-gp120 protein, and IL-6). Significantly, RAP-103 completely protects against Aβ-induced loss of mature and developing synapses and, at 0.1 nM, reverses rods in both rodent and human neurons (T½ ~ 3 h) even in the continuous presence of Aβ. Thus, this orally available, brain-permeable peptide should be highly effective in reducing rod pathology in multifactorial neurological diseases with mixed proteinopathies acting through PrPC/NOX.
Collapse
Affiliation(s)
- Thomas B. Kuhn
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (L.H.T.); (K.P.W.); (A.E.S.)
| | - Laurie S. Minamide
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (L.H.T.); (K.P.W.); (A.E.S.)
| | - Lubna H. Tahtamouni
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (L.H.T.); (K.P.W.); (A.E.S.)
- Department of Biology and Biotechnology, Faculty of Science, The Hashemite University, Zarqa 13133, Jordan
| | - Sydney A. Alderfer
- Department of Chemical and Biological Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA;
| | - Keifer P. Walsh
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (L.H.T.); (K.P.W.); (A.E.S.)
| | - Alisa E. Shaw
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (L.H.T.); (K.P.W.); (A.E.S.)
| | - Omar Yanouri
- Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO 80523, USA;
| | - Henry J. Haigler
- Creative Bio-Peptides, Inc., 10319 Glen Road, Suite 100, Potomac, MD 20854, USA; (H.J.H.); (M.R.R.)
| | - Michael R. Ruff
- Creative Bio-Peptides, Inc., 10319 Glen Road, Suite 100, Potomac, MD 20854, USA; (H.J.H.); (M.R.R.)
| | - James R. Bamburg
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (L.H.T.); (K.P.W.); (A.E.S.)
- Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO 80523, USA;
| |
Collapse
|
3
|
Tahtamouni LH, Alderfer SA, Kuhn TB, Minamide LS, Chanda S, Ruff MR, Bamburg JR. Characterization of a Human Neuronal Culture System for the Study of Cofilin-Actin Rod Pathology. Biomedicines 2023; 11:2942. [PMID: 38001943 PMCID: PMC10669520 DOI: 10.3390/biomedicines11112942] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 10/17/2023] [Accepted: 10/26/2023] [Indexed: 11/26/2023] Open
Abstract
Cofilactin rod pathology, which can initiate synapse loss, has been extensively studied in rodent neurons, hippocampal slices, and in vivo mouse models of human neurodegenerative diseases such as Alzheimer's disease (AD). In these systems, rod formation induced by disease-associated factors, such as soluble oligomers of Amyloid-β (Aβ) in AD, utilizes a pathway requiring cellular prion protein (PrPC), NADPH oxidase (NOX), and cytokine/chemokine receptors (CCR5 and/or CXCR4). However, rod pathways have not been systematically assessed in a human neuronal model. Here, we characterize glutamatergic neurons differentiated from human-induced pluripotent stem cells (iPSCs) for the formation of rods in response to activators of the PrPC-dependent pathway. Optimization of substratum, cell density, and use of glial-conditioned medium yielded a robust system for studying the development of Aβ-induced rods in the absence of glia, suggesting a cell-autonomous pathway. Rod induction in younger neurons requires ectopic expression of PrPC, but this dependency disappears by Day 55. The quantification of proteins within the rod-inducing pathway suggests that increased PrPC and CXCR4 expression may be factors in the doubling of the rod response to Aβ between Days 35 and 55. FDA-approved antagonists to CXCR4 and CCR5 inhibit the rod response. Rods were predominantly observed in dendrites, although severe cytoskeletal disruptions prevented the assignment of over 40% of the rods to either an axon or dendrite. In the absence of glia, a condition in which rods are more readily observed, neurons mature and fire action potentials but do not form functional synapses. However, PSD95-containing dendritic spines associate with axonal regions of pre-synaptic vesicles containing the glutamate transporter, VGLUT1. Thus, our results identified stem cell-derived neurons as a robust model for studying cofilactin rod formation in a human cellular environment and for developing effective therapeutic strategies for the treatment of dementias arising from multiple proteinopathies with different rod initiators.
Collapse
Affiliation(s)
- Lubna H. Tahtamouni
- Department of Biology and Biotechnology, Faculty of Science, The Hashemite University, Zarqa 13133, Jordan;
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (S.C.)
| | - Sydney A. Alderfer
- Department of Chemical and Biological Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523, USA;
| | - Thomas B. Kuhn
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (S.C.)
| | - Laurie S. Minamide
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (S.C.)
| | - Soham Chanda
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (S.C.)
| | - Michael R. Ruff
- Creative Bio-Peptides, Inc., 10319 Glen Road, Suite 100, Potomac, MD 20854, USA;
| | - James R. Bamburg
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA; (T.B.K.); (L.S.M.); (S.C.)
| |
Collapse
|