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Article: Structural and mechanical properties of the red blood cell's cytoplasmic membrane seen through the lens of biophysics.

Himbert, Sebastian / Rheinstädter, Maikel C

2022 Volume 13, Page(s) 953257

Abstract: Red blood cells (RBCs) are the most abundant cell type in the human body and critical suppliers of oxygen. The cells are characterized by a simple structure with no internal organelles. Their two-layered outer shell is composed of a cytoplasmic membrane ( ...

Abstract	Red blood cells (RBCs) are the most abundant cell type in the human body and critical suppliers of oxygen. The cells are characterized by a simple structure with no internal organelles. Their two-layered outer shell is composed of a cytoplasmic membrane (RBC
Language	English
Publishing date	2022-09-12
Publishing country	Switzerland
Document type	Journal Article ; Review
ZDB-ID	2564217-0
ISSN	1664-042X
ISSN	1664-042X
DOI	10.3389/fphys.2022.953257
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Article ; Online: MEDUSA: A cloud-based tool for the analysis of X-ray diffuse scattering to obtain the bending modulus from oriented membrane stacks.

Himbert, Sebastian / Gaboo, Dorian / Brookes, Emre / Nagle, John F / Rheinstädter, Maikel C

PLoS computational biology

2024 Volume 20, Issue 1, Page(s) e1011749

Abstract: An important mechanical property of cells is their membrane bending modulus, κ. Here, we introduce MEDUSA (MEmbrane DiffUse Scattering Analysis), a cloud-based analysis tool to determine the bending modulus, κ, from the analysis of X-ray diffuse ... ...

Abstract	An important mechanical property of cells is their membrane bending modulus, κ. Here, we introduce MEDUSA (MEmbrane DiffUse Scattering Analysis), a cloud-based analysis tool to determine the bending modulus, κ, from the analysis of X-ray diffuse scattering. MEDUSA uses GPU (graphics processing unit) accelerated hardware and a parallelized algorithm to run the calculations efficiently in a few seconds. MEDUSA's graphical user interface allows the user to upload 2-dimensional data collected from different sources, perform background subtraction and distortion corrections, select regions of interest, run the fitting procedure and output the fitted parameters, the membranes' bending modulus κ, and compressional modulus B.
MeSH term(s)	X-Rays ; Cloud Computing ; Radiography ; Algorithms
Language	English
Publishing date	2024-01-08
Publishing country	United States
Document type	Journal Article
ZDB-ID	2193340-6
ISSN	1553-7358 ; 1553-734X
ISSN (online)	1553-7358
ISSN	1553-734X
DOI	10.1371/journal.pcbi.1011749
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Article: Perspective on the Application of Erythrocyte Liposome-Based Drug Delivery for Infectious Diseases.

Krivić, Hannah / Himbert, Sebastian / Rheinstädter, Maikel C

Membranes

2022 Volume 12, Issue 12

Abstract: Nanoparticles are explored as drug carriers with the promise for the treatment of diseases to increase the efficacy and also reduce side effects sometimes seen with conventional drugs. To accomplish this goal, drugs are encapsulated in or conjugated to ... ...

Abstract	Nanoparticles are explored as drug carriers with the promise for the treatment of diseases to increase the efficacy and also reduce side effects sometimes seen with conventional drugs. To accomplish this goal, drugs are encapsulated in or conjugated to the nanocarriers and selectively delivered to their targets. Potential applications include immunization, the delivery of anti-cancer drugs to tumours, antibiotics to infections, targeting resistant bacteria, and delivery of therapeutic agents to the brain. Despite this great promise and potential, drug delivery systems have yet to be established, mainly due to their limitations in physical instability and rapid clearance by the host's immune response. Recent interest has been taken in using red blood cells (RBC) as drug carriers due to their naturally long circulation time, flexible structure, and direct access to many target sites. This includes coating of nanoparticles with the membrane of red blood cells, and the fabrication and manipulation of liposomes made of the red blood cells' cytoplasmic membrane. The properties of these erythrocyte liposomes, such as charge and elastic properties, can be tuned through the incorporation of synthetic lipids to optimize physical properties and the loading efficiency and retention of different drugs. Specificity can be established through the anchorage of antigens and antibodies in the liposomal membrane to achieve targeted delivery. Although still at an early stage, this erythrocyte-based platform shows first promising results in vitro and in animal studies. However, their full potential in terms of increased efficacy and side effect minimization still needs to be explored in vivo.
Language	English
Publishing date	2022-12-03
Publishing country	Switzerland
Document type	Journal Article ; Review
ZDB-ID	2614641-1
ISSN	2077-0375
ISSN	2077-0375
DOI	10.3390/membranes12121226
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Article: The Formation of RNA Pre-Polymers in the Presence of Different Prebiotic Mineral Surfaces Studied by Molecular Dynamics Simulations.

Dujardin, Alix / Himbert, Sebastian / Pudritz, Ralph / Rheinstädter, Maikel C

Life (Basel, Switzerland)

2022 Volume 13, Issue 1

Abstract: We used all-atom Molecular Dynamics (MD) computer simulations to study the formation of pre-polymers between the four nucleotides in RNA (AMP, UMP, CMP, GMP) in the presence of different substrates that could have been present in a prebiotic environment. ...

Abstract	We used all-atom Molecular Dynamics (MD) computer simulations to study the formation of pre-polymers between the four nucleotides in RNA (AMP, UMP, CMP, GMP) in the presence of different substrates that could have been present in a prebiotic environment. Pre-polymers are C3'-C5' hydrogen-bonded nucleotides that have been suggested to be the precursors of phosphodiester-bonded RNA polymers. We simulated wet-dry cycles by successively removing water molecules from the simulations, from ~60 to 3 water molecules per nucleotide. The nine substrates in this study include three clay minerals, one mica, one phosphate mineral, one silica, and two metal oxides. The substrates differ in their surface charge and ability to form hydrogen bonds with the nucleotides. From the MD simulations, we quantify the interactions between different nucleotides, and between nucleotides and substrates. For comparison, we included graphite as an inert substrate, which is not charged and cannot form hydrogen bonds. We also simulated the dehydration of a nucleotide-only system, which mimics the drying of small droplets. The number of hydrogen bonds between nucleotides and nucleotides and substrates was found to increase significantly when water molecules were removed from the systems. The largest number of C3'-C5' hydrogen bonds between nucleotides occurred in the graphite and nucleotide-only systems. While the surface of the substrates led to an organization and periodic arrangement of the nucleotides, none of the substrates was found to be a catalyst for pre-polymer formation, neither at full hydration, nor when dehydrated. While confinement and dehydration seem to be the main drivers for hydrogen bond formation, substrate interactions reduced the interactions between nucleotides in all cases. Our findings suggest that small supersaturated water droplets that could have been produced by geysers or springs on the primitive Earth may play an important role in non-enzymatic RNA polymerization.
Language	English
Publishing date	2022-12-30
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2662250-6
ISSN	2075-1729
ISSN	2075-1729
DOI	10.3390/life13010112
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Article ; Online: Erythro-PmBs: A Selective Polymyxin B Delivery System Using Antibody-Conjugated Hybrid Erythrocyte Liposomes.

Krivić, Hannah / Himbert, Sebastian / Sun, Ruthie / Feigis, Michal / Rheinstädter, Maikel C

ACS infectious diseases

2022 Volume 8, Issue 10, Page(s) 2059–2072

Abstract: As a result of the growing worldwide antibiotic resistance crisis, many currently existing antibiotics have become ineffective due to bacteria developing resistive mechanisms. There are a limited number of potent antibiotics that are successful at ... ...

Abstract	As a result of the growing worldwide antibiotic resistance crisis, many currently existing antibiotics have become ineffective due to bacteria developing resistive mechanisms. There are a limited number of potent antibiotics that are successful at suppressing microbial growth, such as polymyxin B (PmB); however, these are often deemed as a last resort due to their toxicity. We present a novel PmB delivery system constructed by conjugating hybrid erythrocyte liposomes with antibacterial antibodies to combine a high loading efficiency with guided delivery. The retention of PmB is enhanced by incorporating negatively charged lipids into the red blood cells' cytoplasmic membrane (RBC
MeSH term(s)	Anti-Bacterial Agents/pharmacology ; Erythrocytes ; Erythromycin/pharmacology ; Escherichia coli ; Liposomes/pharmacology ; Maleimides ; Polymyxin B/pharmacology
Chemical Substances	Anti-Bacterial Agents ; Liposomes ; Maleimides ; Erythromycin (63937KV33D) ; Polymyxin B (J2VZ07J96K)
Language	English
Publishing date	2022-09-29
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	2373-8227
ISSN (online)	2373-8227
DOI	10.1021/acsinfecdis.2c00017
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Article ; Online: Alkylated EDTA potentiates antibacterial photodynamic activity of protoporphyrin.

Piao, Ying / Himbert, Sebastian / Li, Zifan / Liu, Jun / Zhao, Zhihao / Yu, Huahai / Liu, Shuangshuang / Shao, Shiqun / Fefer, Michael / Rheinstädter, Maikel C / Shen, Youqing

Journal of nanobiotechnology

2024 Volume 22, Issue 1, Page(s) 161

Abstract: Antibiotic resistance has garnered significant attention due to the scarcity of new antibiotics in development. Protoporphyrin IX (PpIX)-mediated photodynamic therapy shows promise as a novel antibacterial strategy, serving as an alternative to ... ...

Abstract	Antibiotic resistance has garnered significant attention due to the scarcity of new antibiotics in development. Protoporphyrin IX (PpIX)-mediated photodynamic therapy shows promise as a novel antibacterial strategy, serving as an alternative to antibiotics. However, the poor solubility of PpIX and its tendency to aggregate greatly hinder its photodynamic efficacy. In this study, we demonstrate that alkylated EDTA derivatives (aEDTA), particularly C14-EDTA, can enhance the solubility of PpIX by facilitating its dispersion in aqueous solutions. The combination of C14-EDTA and PpIX exhibits potent antibacterial activity against Staphylococcus aureus (S. aureus) when exposed to LED light irradiation. Furthermore, this combination effectively eradicates S. aureus biofilms, which are known to be strongly resistant to antibiotics, and demonstrates high therapeutic efficacy in an animal model of infected ulcers. Mechanistic studies reveal that C14-EDTA can disrupt PpIX crystallization, increase bacterial membrane permeability and sequester divalent cations, thereby improving the accumulation of PpIX in bacteria. This, in turn, enhances reactive oxygen species (ROS) production and the antibacterial photodynamic activity. Overall, this effective strategy holds great promise in combating antibiotic-resistant strains.
MeSH term(s)	Animals ; Staphylococcus aureus ; Protoporphyrins/pharmacology ; Edetic Acid/pharmacology ; Photochemotherapy ; Anti-Bacterial Agents/pharmacology ; Anti-Bacterial Agents/chemistry ; Photosensitizing Agents/pharmacology ; Photosensitizing Agents/chemistry
Chemical Substances	protoporphyrin IX (C2K325S808) ; Protoporphyrins ; Edetic Acid (9G34HU7RV0) ; Anti-Bacterial Agents ; Photosensitizing Agents
Language	English
Publishing date	2024-04-08
Publishing country	England
Document type	Journal Article
ZDB-ID	2100022-0
ISSN	1477-3155 ; 1477-3155
ISSN (online)	1477-3155
ISSN	1477-3155
DOI	10.1186/s12951-024-02353-3
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Article ; Online: The Effects of Resveratrol, Caffeine, β-Carotene, and Epigallocatechin Gallate (EGCG) on Amyloid-

Gastaldo, Isabella P / Himbert, Sebastian / Ram, Udbhav / Rheinstädter, Maikel C

Molecular nutrition & food research

2020 Volume 64, Issue 22, Page(s) e2000632

Abstract: Scope: Alzheimer's disease is a neurodegenerative condition marked by the formation and aggregation of amyloid-β (Aβ) peptides. There exists, to this day, no cure or effective prevention for the disease; however, there is evidence that a healthy diet ... ...

Abstract	Scope: Alzheimer's disease is a neurodegenerative condition marked by the formation and aggregation of amyloid-β (Aβ) peptides. There exists, to this day, no cure or effective prevention for the disease; however, there is evidence that a healthy diet and certain food products can slow down first occurrence and progression. To investigate if food ingredients can interact with peptide aggregates, synthetic membranes that contained aggregates consisting of cross-β sheets of the membrane active fragment A Methods and results: The impact of resveratrol, found in grapes, caffeine, the main active ingredient in coffee, β-carotene, found in orange fruits and vegetables, and epigallocatechin gallate (EGCG), a component of green tea, on the size and volume fraction of Aβ aggregates is studied using optical and fluorescence microscopy, X-ray diffraction, UV-vis spectroscopy, and molecular dynamics simulations. All compounds are membrane active and spontaneously partitioned in the synthetic brain membranes. While resveratrol and caffeine lead to membrane thickening and reduced membrane fluidity, β-carotene and EGCG preserve or increase fluidity. Conclusion: Resveratrol and caffeine do not reduce the volume fraction of peptide aggregates while β-carotene significantly reduces plaque size. Interestingly, EGCG dissolves peptide aggregates and significantly decreases the corresponding cross-β and β-sheet signals.
MeSH term(s)	Amyloid beta-Peptides/metabolism ; Brain/cytology ; Caffeine/chemistry ; Caffeine/pharmacology ; Catechin/analogs & derivatives ; Catechin/chemistry ; Catechin/pharmacology ; Cell Membrane/chemistry ; Cell Membrane/drug effects ; Microscopy, Fluorescence ; Molecular Dynamics Simulation ; Peptide Fragments/metabolism ; Resveratrol/chemistry ; Resveratrol/pharmacology ; Spectrophotometry, Ultraviolet ; X-Ray Diffraction ; beta Carotene/chemistry ; beta Carotene/pharmacology
Chemical Substances	Amyloid beta-Peptides ; Peptide Fragments ; amyloid beta-protein (25-35) ; beta Carotene (01YAE03M7J) ; Caffeine (3G6A5W338E) ; Catechin (8R1V1STN48) ; epigallocatechin gallate (BQM438CTEL) ; Resveratrol (Q369O8926L)
Language	English
Publishing date	2020-10-19
Publishing country	Germany
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2160372-8
ISSN	1613-4133 ; 1613-4125
ISSN (online)	1613-4133
ISSN	1613-4125
DOI	10.1002/mnfr.202000632
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Article ; Online: Anesthetics significantly increase the amount of intramembrane water in lipid membranes.

Himbert, Sebastian / Zhang, Lili / Alsop, Richard J / Cristiglio, Viviana / Fragneto, Giovanna / Rheinstädter, Maikel C

Soft matter

2020 Volume 16, Issue 42, Page(s) 9674–9682

Abstract: The potency of anesthesia was directly linked to the partitioning of the drug molecules in cell membranes by Meyer and Overton. Many molecules interact with lipid bilayers and lead to structural and functional changes. It remains an open question which ... ...

Abstract	The potency of anesthesia was directly linked to the partitioning of the drug molecules in cell membranes by Meyer and Overton. Many molecules interact with lipid bilayers and lead to structural and functional changes. It remains an open question which change in membrane properties is responsible for a potential anesthetic effect or if anesthetics act by binding to direct targets. We studied the effect of ethanol, diethyl ether and isoflurane on the water distribution in lipid bilayers by combining all-atom molecular dynamics simulations and neutron diffraction experiments. The simulations show strong membrane-drug interactions with partitioning coefficients of 38%, 92% and 100% for ethanol, diethyl ether and isoflurane, respectively, and provide evidence for an increased water partitioning in the membrane core. The amount of intramembrane water molecules was experimentally determined by selectively deuterium labeling lipids, anesthetic drug and water molecules in neutron diffraction experiments. Four additional water molecules per lipid were observed in the presence of ethanol. Diethyl ether and isoflurane were found to significantly increase the amount of intramembrane water by 25% (8 water molecules). This increase in intramembrane water may contribute to the non-specific interactions between anesthetics and lipid membranes.
MeSH term(s)	Anesthetics ; Lipid Bilayers ; Membranes ; Molecular Dynamics Simulation ; Water
Chemical Substances	Anesthetics ; Lipid Bilayers ; Water (059QF0KO0R)
Language	English
Publishing date	2020-08-16
Publishing country	England
Document type	Journal Article
ZDB-ID	2191476-X
ISSN	1744-6848 ; 1744-683X
ISSN (online)	1744-6848
ISSN	1744-683X
DOI	10.1039/d0sm01271h
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Article ; Online: Curcumin and Homotaurine Suppress Amyloid-β

Zou, Xingyuan / Himbert, Sebastian / Dujardin, Alix / Juhasz, Janos / Ros, Samantha / Stöver, Harald D H / Rheinstädter, Maikel C

ACS chemical neuroscience

2021 Volume 12, Issue 8, Page(s) 1395–1405

Abstract: Amyloid-β (Aβ) peptides spontaneously aggregate into β- and cross-β-sheets in model brain membranes. These nanometer sized can fuse into larger micrometer sized clusters and become extracellular and serve as nuclei for further plaque and fibril growth. ... ...

Abstract	Amyloid-β (Aβ) peptides spontaneously aggregate into β- and cross-β-sheets in model brain membranes. These nanometer sized can fuse into larger micrometer sized clusters and become extracellular and serve as nuclei for further plaque and fibril growth. Curcumin and homotaurine represent two different types of Aβ aggregation inhibitors. While homotaurine is a peptic antiaggregant that binds to amyloid peptides, curcumin is a nonpeptic molecule that can inhibit aggregation by changing membrane properties. By using optical and fluorescent microscopy, X-ray diffraction, and UV-vis spectroscopy, we study the effect of curcumin and homotaurine on Aβ
MeSH term(s)	Alzheimer Disease ; Amyloid/metabolism ; Amyloid beta-Peptides/metabolism ; Brain/metabolism ; Curcumin/pharmacology ; Humans ; Peptide Fragments ; Taurine/analogs & derivatives
Chemical Substances	Amyloid ; Amyloid beta-Peptides ; Peptide Fragments ; Taurine (1EQV5MLY3D) ; tramiprosate (5K8EAX0G53) ; Curcumin (IT942ZTH98)
Language	English
Publishing date	2021-04-07
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	1948-7193
ISSN (online)	1948-7193
DOI	10.1021/acschemneuro.1c00057
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Article ; Online: Blood bank storage of red blood cells increases RBC cytoplasmic membrane order and bending rigidity.

Himbert, Sebastian / Qadri, Syed M / Sheffield, William P / Schubert, Peter / D'Alessandro, Angelo / Rheinstädter, Maikel C

PloS one

2021 Volume 16, Issue 11, Page(s) e0259267

Abstract: Blood banks around the world store blood components for several weeks ensuring its availability for transfusion medicine. Red blood cells (RBCs) are known to undergo compositional changes during storage, which may impact the cells' function and ... ...

Abstract	Blood banks around the world store blood components for several weeks ensuring its availability for transfusion medicine. Red blood cells (RBCs) are known to undergo compositional changes during storage, which may impact the cells' function and eventually the recipients' health. We extracted the RBC's cytoplasmic membrane (RBCcm) to study the effect of storage on the membranes' molecular structure and bending rigidity by a combination of X-ray diffraction (XRD), X-ray diffuse scattering (XDS) and coarse grained Molecular Dynamics (MD) simulations. Blood was stored in commercial blood bags for 2 and 5 weeks, respectively and compared to freshly drawn blood. Using mass spectrometry, we measured an increase of fatty acids together with a slight shift towards shorter tail lengths. We observe an increased fraction (6%) of liquid ordered (lo) domains in the RBCcms with storage time, and an increased lipid packing in these domains, leading to an increased membrane thickness and membrane order. The size of both, lo and liquid disordered (ld) lipid domains was found to decrease with increased storage time by up to 25%. XDS experiments reveal a storage dependent increase in the RBCcm's bending modulus κ by a factor of 2.8, from 1.9 kBT to 5.3 kBT. MD simulations were conducted in the absence of proteins. The results show that the membrane composition has a small contribution to the increased bending rigidity and suggests additional protein-driven mechanisms.
MeSH term(s)	Blood Preservation ; Cell Membrane ; Erythrocytes ; Molecular Dynamics Simulation
Language	English
Publishing date	2021-11-12
Publishing country	United States
Document type	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
ZDB-ID	2267670-3
ISSN	1932-6203 ; 1932-6203
ISSN (online)	1932-6203
ISSN	1932-6203
DOI	10.1371/journal.pone.0259267
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