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Biomolecules Mar 2024Lipid rafts, specialised microdomains within cell membranes, play a central role in orchestrating various aspects of neurodevelopment, ranging from neural... (Review)
Review
Lipid rafts, specialised microdomains within cell membranes, play a central role in orchestrating various aspects of neurodevelopment, ranging from neural differentiation to the formation of functional neuronal networks. This review focuses on the multifaceted involvement of lipid rafts in key neurodevelopmental processes, including neural differentiation, synaptogenesis and myelination. Through the spatial organisation of signalling components, lipid rafts facilitate precise signalling events that determine neural fate during embryonic development and in adulthood. The evolutionary conservation of lipid rafts underscores their fundamental importance for the structural and functional complexity of the nervous system in all species. Furthermore, there is increasing evidence that environmental factors can modulate the composition and function of lipid rafts and influence neurodevelopmental processes. Understanding the intricate interplay between lipid rafts and neurodevelopment not only sheds light on the fundamental mechanisms governing brain development but also has implications for therapeutic strategies aimed at cultivating neuronal networks and addressing neurodevelopmental disorders.
Topics: Cell Membrane; Signal Transduction; Neurons; Brain; Membrane Microdomains
PubMed: 38540780
DOI: 10.3390/biom14030362 -
Cells Mar 2024High blood levels of low-density lipoprotein (LDL)-cholesterol (LDL-C) are associated with atherosclerosis, mainly by promoting foam cell accumulation in vessels. As...
Low Density Lipoprotein Cholesterol Decreases the Expression of Adenosine A Receptor and Lipid Rafts-Protein Flotillin-1: Insights on Cardiovascular Risk of Hypercholesterolemia.
High blood levels of low-density lipoprotein (LDL)-cholesterol (LDL-C) are associated with atherosclerosis, mainly by promoting foam cell accumulation in vessels. As cholesterol is an essential component of cell plasma membranes and a regulator of several signaling pathways, LDL-C excess may have wider cardiovascular toxicity. We examined, in untreated hypercholesterolemia (HC) patients, selected regardless of the cause of LDL-C accumulation, and in healthy participants (HP), the expression of the adenosine A receptor (AR), an anti-inflammatory and vasodilatory protein with cholesterol-dependent modulation, and Flotillin-1, protein marker of cholesterol-enriched plasma membrane domains. Blood cardiovascular risk and inflammatory biomarkers were measured. AR and Flotillin-1 expression in peripheral blood mononuclear cells (PBMC) was lower in patients compared to HP and negatively correlated to LDL-C blood levels. No other differences were observed between the two groups apart from transferrin and ferritin concentrations. AR and Flotillin-1 proteins levels were positively correlated in the whole study population. Incubation of HP PBMCs with LDL-C caused a similar reduction in AR and Flotillin-1 expression. We suggest that LDL-C affects AR expression by impacting cholesterol-enriched membrane microdomains. Our results provide new insights into the molecular mechanisms underlying cholesterol toxicity, and may have important clinical implication for assessment and treatment of cardiovascular risk in HC.
Topics: Humans; Hypercholesterolemia; Cholesterol, LDL; Receptor, Adenosine A2A; Leukocytes, Mononuclear; Adenosine; Cardiovascular Diseases; Risk Factors; Cholesterol; Carrier Proteins; Heart Disease Risk Factors; Membrane Microdomains; Membrane Proteins
PubMed: 38534331
DOI: 10.3390/cells13060488 -
Cells Mar 2024The ubiquitous second messenger 3',5'-cyclic adenosine monophosphate (cAMP) regulates cardiac excitation-contraction coupling (ECC) by signaling in discrete subcellular...
The ubiquitous second messenger 3',5'-cyclic adenosine monophosphate (cAMP) regulates cardiac excitation-contraction coupling (ECC) by signaling in discrete subcellular microdomains. Phosphodiesterase subfamilies 4B and 4D are critically involved in the regulation of cAMP signaling in mammalian cardiomyocytes. Alterations of PDE4 activity in human hearts has been shown to result in arrhythmias and heart failure. Here, we sought to systematically investigate specific roles of PDE4B and PDE4D in the regulation of cAMP dynamics in three distinct subcellular microdomains, one of them located at the caveolin-rich plasma membrane which harbors the L-type calcium channels (LTCCs), as well as at two sarco/endoplasmic reticulum (SR) microdomains centered around SR Ca-ATPase (SERCA2a) and cardiac ryanodine receptor type 2 (RyR2). Transgenic mice expressing Förster Resonance Energy Transfer (FRET)-based cAMP-specific biosensors targeted to caveolin-rich plasma membrane, SERCA2a and RyR2 microdomains were crossed to PDE4B-KO and PDE4D-KO mice. Direct analysis of the specific effects of both PDE4 subfamilies on local cAMP dynamics was performed using FRET imaging. Our data demonstrate that all three microdomains are differentially regulated by these PDE4 subfamilies. Whereas both are involved in cAMP regulation at the caveolin-rich plasma membrane, there are clearly two distinct cAMP microdomains at the SR formed around RyR2 and SERCA2a, which are preferentially controlled by PDE4B and PDE4D, respectively. This correlates with local cAMP-dependent protein kinase (PKA) substrate phosphorylation and arrhythmia susceptibility. Immunoprecipitation assays confirmed that PDE4B is associated with RyR2 along with PDE4D. Stimulated Emission Depletion (STED) microscopy of immunostained cardiomyocytes suggested possible co-localization of PDE4B with both sarcolemmal and RyR2 microdomains. In conclusion, our functional approach could show that both PDE4B and PDE4D can differentially regulate cardiac cAMP microdomains associated with calcium homeostasis. PDE4B controls cAMP dynamics in both caveolin-rich plasma membrane and RyR2 vicinity. Interestingly, PDE4B is the major regulator of the RyR2 microdomain, as opposed to SERCA2a vicinity, which is predominantly under PDE4D control, suggesting a more complex regulatory pattern than previously thought, with multiple PDEs acting at the same location.
Topics: Mice; Humans; Animals; Calcium; Ryanodine Receptor Calcium Release Channel; Cyclic AMP; Myocytes, Cardiac; Mice, Transgenic; Caveolins; Mammals
PubMed: 38534320
DOI: 10.3390/cells13060476 -
Acta Physiologica (Oxford, England) Apr 2024Trafficking, membrane retention, and signal-specific regulation of the Na/H exchanger 3 (NHE3) are modulated by the Na/H Exchanger Regulatory Factor (NHERF) family of...
AIM
Trafficking, membrane retention, and signal-specific regulation of the Na/H exchanger 3 (NHE3) are modulated by the Na/H Exchanger Regulatory Factor (NHERF) family of PDZ-adapter proteins. This study explored the assembly of NHE3 and NHERF2 with the cGMP-dependent kinase II (cGKII) within detergent-resistant membrane microdomains (DRMs, "lipid rafts") during in vivo guanylate cycle C receptor (Gucy2c) activation in murine small intestine.
METHODS
Small intestinal brush border membranes (siBBMs) were isolated from wild type, NHE3-deficient, cGMP-kinase II-deficient, and NHERF2-deficient mice, after oral application of the heat-stable Escherichia coli toxin (STa) analog linaclotide. Lipid raft and non-raft fractions were separated by Optiprep density gradient centrifugation of Triton X-solubilized siBBMs. Confocal microscopy was performed to study NHE3 redistribution after linaclotide application in vivo.
RESULTS
In the WT siBBM, NHE3, NHERF2, and cGKII were strongly raft associated. The raft association of NHE3, but not of cGKII, was NHERF2 dependent. After linaclotide application to WT mice, lipid raft association of NHE3 decreased, that of cGKII increased, while that of NHERF2 did not change. NHE3 expression in the BBM shifted from a microvillar to a terminal web region. The linaclotide-induced decrease in NHE3 raft association and in microvillar abundance was abolished in cGKII-deficient mice, and strongly reduced in NHERF2-deficient mice.
CONCLUSION
NHE3, cGKII, and NHERF2 form a lipid raft-associated signal complex in the siBBM, which mediates the inhibition of salt and water absorption by Gucy2c activation. NHERF2 enhances the raft association of NHE3, which is essential for its close interaction with the exclusively raft-associated activated cGKII.
Topics: Animals; Mice; Cyclic GMP-Dependent Protein Kinases; Intestine, Small; Membrane Microdomains; Microvilli; Sodium-Hydrogen Exchanger 3; Sodium-Hydrogen Exchangers; Cyclic GMP-Dependent Protein Kinase Type II
PubMed: 38533975
DOI: 10.1111/apha.14125 -
Current Biology : CB Mar 2024During cancer progression, tumor cells need to disseminate by remodeling the extracellular tumor matrix. A recent study sheds light on the intricate cooperation between...
During cancer progression, tumor cells need to disseminate by remodeling the extracellular tumor matrix. A recent study sheds light on the intricate cooperation between caveolae and invadosomes that facilitates the spread of cancer cells.
Topics: Humans; Podosomes; Caveolae; Extracellular Matrix; Neoplasm Invasiveness; Crime
PubMed: 38531317
DOI: 10.1016/j.cub.2024.02.006 -
Biochemical Society Transactions Apr 2024Caveolin-1 (Cav1) is a 22 kDa intracellular protein that is the main protein constituent of bulb-shaped membrane invaginations known as caveolae. Cav1 can be also... (Review)
Review
Caveolin-1 (Cav1) is a 22 kDa intracellular protein that is the main protein constituent of bulb-shaped membrane invaginations known as caveolae. Cav1 can be also found in functional non-caveolar structures at the plasma membrane called scaffolds. Scaffolds were originally described as SDS-resistant oligomers composed of 10-15 Cav1 monomers observable as 8S complexes by sucrose velocity gradient centrifugation. Recently, cryoelectron microscopy (cryoEM) and super-resolution microscopy have shown that 8S complexes are interlocking structures composed of 11 Cav1 monomers each, which further assemble modularly to form higher-order scaffolds and caveolae. In addition, Cav1 can act as a critical signaling regulator capable of direct interactions with multiple client proteins, in particular, the endothelial nitric oxide (NO) synthase (eNOS), a role believed by many to be attributable to the highly conserved and versatile scaffolding domain (CSD). However, as the CSD is a hydrophobic domain located by cryoEM to the periphery of the 8S complex, it is predicted to be enmeshed in membrane lipids. This has led some to challenge its ability to interact directly with client proteins and argue that it impacts signaling only indirectly via local alteration of membrane lipids. Here, based on recent advances in our understanding of higher-order Cav1 structure formation, we discuss how the Cav1 CSD may function through both lipid and protein interaction and propose an alternate view in which structural modifications to Cav1 oligomers may impact exposure of the CSD to cytoplasmic client proteins, such as eNOS.
Topics: Animals; Humans; Caveolae; Caveolin 1; Cell Membrane; Cryoelectron Microscopy; Nitric Oxide Synthase Type III; Protein Domains; Signal Transduction
PubMed: 38526159
DOI: 10.1042/BST20231570 -
Langmuir : the ACS Journal of Surfaces... Apr 2024The polymer brush architecture of the end-tethered polymer molecules is one of the most widely used efficient methods to regulate interfacial interactions in colloidal...
The polymer brush architecture of the end-tethered polymer molecules is one of the most widely used efficient methods to regulate interfacial interactions in colloidal systems found in live matter and manufactured materials. Emerging applications of polymer brush structures require solutions to new tasks in the control of interfacial interactions. The rapid development of live cell manufacturing relies on scalable and efficient cell harvesting methods. Stimuli-responsive surfaces made of surface-grafted poly(-isopropylacrylamide) (PNIPAM) can bind and detach the adherent cell upon changes in temperature and have been used for cell growth and harvesting. The applications are limited by the requirement to satisfy a range of PNIPAM coating characteristics that depend on the dimensions of the integrin complex in the cell membrane and the basal surface. The analysis of the microstructured surfaces, when adhesive and disjoining functions of the microdomains are decoupled, shows that many limitations of PNIPAM one-component coatings can be avoided by using a much broader range of structural characteristics of the microstructured interfaces composed of alternating disjoining PNIPAM domains and adhesive polymeric domains with cell-affinity functional groups. Temperature-controlled reversible adhesion to such microstructured interfaces is studied here experimentally with model systems of solid spherical particles and by employing simulations for solid and soft membranes interacting with the microstructured surfaces to mimic interactions with soft and solid disk-like particles.
PubMed: 38525827
DOI: 10.1021/acs.langmuir.4c00062 -
Biochimica Et Biophysica Acta.... Jun 2024Calcium signaling stands out as the most widespread and universally used signaling system and is of utmost importance for immunity. Controlled elevations in cytosolic... (Review)
Review
Calcium signaling stands out as the most widespread and universally used signaling system and is of utmost importance for immunity. Controlled elevations in cytosolic and organellar Ca concentrations in T cells control complex and essential effector functions including proliferation, differentiation, cytokine secretion, and cytotoxicity, among others. Additionally, disruptions in Ca regulation in T cells contribute to diverse autoimmune, inflammatory, and immunodeficiency conditions. Among the initial intracellular signals, which occurring even before T cell receptor (TCR) stimulation are highly localized, spatially and temporally restricted so-called Ca microdomains, caused by adhesion to extracellular matrix proteins (ECM proteins). The Ca microdomains present both before and within the initial seconds following TCR stimulation are likely to play a crucial role in fine-tuning the downstream activity of T cell activation and thus, shaping an adaptive immune response. In this review, the emphasis is on the recent advances of adhesion-dependent Ca microdomains (ADCM) in the absence of TCR stimulation, initial Ca microdomains evoked by TCR stimulation (TDCM), the downstream signaling processes as well as possible therapeutic targets for interventions.
Topics: Humans; Adaptive Immunity; Calcium Signaling; T-Lymphocytes; Calcium; Animals; Receptors, Antigen, T-Cell; Lymphocyte Activation; Membrane Microdomains
PubMed: 38522726
DOI: 10.1016/j.bbamcr.2024.119710 -
ELife Mar 2024Large transcellular pores elicited by bacterial mono-ADP-ribosyltransferase (mART) exotoxins inhibiting the small RhoA GTPase compromise the endothelial barrier. Recent...
Large transcellular pores elicited by bacterial mono-ADP-ribosyltransferase (mART) exotoxins inhibiting the small RhoA GTPase compromise the endothelial barrier. Recent advances in biophysical modeling point toward membrane tension and bending rigidity as the minimal set of mechanical parameters determining the nucleation and maximal size of transendothelial cell macroaperture (TEM) tunnels induced by bacterial RhoA-targeting mART exotoxins. We report that cellular depletion of caveolin-1, the membrane-embedded building block of caveolae, and depletion of cavin-1, the master regulator of caveolae invaginations, increase the number of TEMs per cell. The enhanced occurrence of TEM nucleation events correlates with a reduction in cell height due to the increase in cell spreading and decrease in cell volume, which, together with the disruption of RhoA-driven F-actin meshwork, favor membrane apposition for TEM nucleation. Strikingly, caveolin-1 specifically controls the opening speed of TEMs, leading to their dramatic 5.4-fold larger widening. Consistent with the increase in TEM density and width in siCAV1 cells, we record a higher lethality in CAV1 KO mice subjected to a catalytically active mART exotoxin targeting RhoA during staphylococcal bloodstream infection. Combined theoretical modeling with independent biophysical measurements of plasma membrane bending rigidity points toward a specific contribution of caveolin-1 to membrane stiffening in addition to the role of cavin-1/caveolin-1-dependent caveolae in the control of membrane tension homeostasis.
Topics: Animals; Mice; Caveolae; Caveolin 1; Cell Membrane; Endothelial Cells; Exotoxins
PubMed: 38517935
DOI: 10.7554/eLife.92078 -
Journal of Agricultural and Food... Apr 2024Macrophage inflammation and oxidative stress promote atherosclerosis progression. Naringenin is a naturally occurring flavonoid with antiatherosclerotic properties....
Macrophage inflammation and oxidative stress promote atherosclerosis progression. Naringenin is a naturally occurring flavonoid with antiatherosclerotic properties. Here, we elucidated the effects of naringenin on monocyte/macrophage endothelial infiltration and vascular inflammation. We found naringenin inhibited oxidized low-density lipoprotein (oxLDL)-induced pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α toward an M2 macrophage phenotype and inhibited oxLDL-induced TLR4 (Toll-like receptor 4) membrane translocation and downstream NF-κB transcriptional activity. Results from flow cytometric analysis showed that naringenin reduced monocyte/macrophage infiltration in the aorta of high-fat-diet-treated ApoE-deficient mice. The aortic cytokine levels were also inhibited in naringenin-treated mice. Further, we found that naringenin reduced lipid raft clustering and acid sphingomyelinase (ASMase) membrane gathering and inhibited the TLR4 and NADPH oxidase subunit p47phox membrane recruitment, which reduced the inflammatory response. Recombinant ASMase treatment or overexpression of ASMase abolished the naringenin function and activated macrophage and vascular inflammation. We conclude that naringenin inhibits ASMase-mediated lipid raft redox signaling to attenuate macrophage activation and vascular inflammation.
Topics: Mice; Animals; Toll-Like Receptor 4; Sphingomyelin Phosphodiesterase; Inflammation; NF-kappa B; Cytokines; NADPH Oxidases; Membrane Microdomains; Flavanones
PubMed: 38516841
DOI: 10.1021/acs.jafc.3c07874