Pentacyclic triterpenes modulate liposome membrane fluidity and permeability depending on membrane cholesterol content

2021 ◽  
pp. 121232
Author(s):  
Samar Kaddah ◽  
Nathalie Khreich ◽  
Fouad Kaddah ◽  
Catherine Charcosset ◽  
Hélène Greige-Gerges
Keyword(s):  
Membrane Fluidity ◽  
Cholesterol Content ◽  
Membrane Cholesterol ◽  
Liposome Membrane ◽  
Pentacyclic Triterpenes

scholarly journals Cholesterol is the main regulator of the carbon dioxide permeability of biological membranes

2018 ◽  
Vol 315 (2) ◽  
pp. C137-C140 ◽  
Author(s):  
Mariela Arias-Hidalgo ◽  
Samer Al-Samir ◽  
Gerolf Gros ◽  
Volker Endeward
Keyword(s):  
Carbon Dioxide ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Biological Membranes ◽  
Cell Types ◽  
Cholesterol Content ◽  
Membrane Cholesterol ◽  
Main Regulator

We present here a compilation of membrane CO2 permeabilities (Pco2) for various cell types from the literature. Pco2 values vary over more than two orders of magnitude. Relating Pco2 to the cholesterol content of the membranes shows that, with the exception of red blood cells, it is essentially membrane cholesterol that determines the value of Pco2. Thus, the observed strong modulation of Pco2 in the majority of membranes is caused by cholesterol rather than gas channels.

scholarly journals Activity of Antimicrobial Peptide Protegrin-1 is Tuned by Membrane Cholesterol Content

2015 ◽  
Vol 108 (2) ◽  
pp. 550a-551a ◽  
Author(s):  
J. Michael Henderson ◽  
Kathleen D. Cao ◽  
Zhiliang L. Gong ◽  
Gregory T. Tietjen ◽  
Charles T.R. Heffern ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Cholesterol Content ◽  
Membrane Cholesterol

scholarly journals Inefficient HIV-1 trans Infection of CD4 + T Cells by Macrophages from HIV-1 Nonprogressors Is Associated with Altered Membrane Cholesterol and DC-SIGN

2018 ◽  
Vol 92 (13) ◽  
Author(s):  
Diana C. DeLucia ◽  
Charles R. Rinaldo ◽  
Giovanna Rappocciolo
Keyword(s):  
T Cells ◽  
Hiv Infection ◽  
Disease Progression ◽  
B Lymphocytes ◽  
Cholesterol Content ◽  
Therapeutic Strategies ◽  
Membrane Cholesterol ◽  
Data Support ◽  
Early Endosomes ◽  
Hiv 1

ABSTRACT Professional antigen-presenting cells (APC; myeloid dendritic cells [DC] and macrophages [MΦ]; B lymphocytes) mediate highly efficient HIV-1 infection of CD4 + T cells, termed trans infection, that could contribute to HIV-1 pathogenesis. We have previously shown that lower cholesterol content in DC and B lymphocytes is associated with a lack of HIV-1 trans infection in HIV-1-infected nonprogressors (NP). Here, we assessed whether HIV-1 trans infection mediated by another major APC, MΦ, is deficient in NP due to altered cholesterol metabolism. When comparing healthy HIV-1 seronegatives (SN), rapid progressors (PR), and NP, we found that monocyte-derived MΦ from NP did not mediate HIV-1 trans infection of autologous CD4 + T cells, in contrast to efficient trans infection mediated by SN and PR MΦ. MΦ trans infection efficiency was directly associated with the number of DC-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN)-expressing MΦ. Significantly fewer NP MΦ expressed DC-SIGN. Unesterified (free) cholesterol in MΦ cell membranes and lipid rafting was significantly lower in NP than PR, as was virus internalization in early endosomes. Furthermore, simvastatin (SIMV) decreased the subpopulation of DC-SIGN + MΦ as well as cis and trans infection. Notably, SIMV decreased cell membrane cholesterol and led to lipid raft dissociation, effectively mimicking the incompetent APC trans infection environment characteristic of NP. Our data support that DC-SIGN and membrane cholesterol are central to MΦ trans infection, and a lack of these limits HIV-1 disease progression. Targeting the ability of MΦ to drive HIV-1 dissemination in trans could enhance HIV-1 therapeutic strategies. IMPORTANCE Despite the success of combination antiretroviral therapy, neither a vaccine nor a cure for HIV infection has been developed, demonstrating a need for novel prophylactic and therapeutic strategies. Here, we show that efficiency of MΦ-mediated HIV trans infection of CD4 + T cells is a unique characteristic associated with control of disease progression, and it is impaired in HIV-infected NP. In vitro treatment of MΦ from healthy donors with SIMV lowers their cholesterol content, which results in a strongly reduced trans infection ability, similar to the levels of MΦ from NP. Taken together, our data support the hypothesis that MΦ-mediated HIV-1 trans infection plays a role in HIV infection and disease progression and demonstrate that the use of SIMV to decrease this mechanism of virus transfer should be considered for future HIV therapeutic development.

93 CALCIUM REMOVAL INCREASES THE PROTECTIVE EFFECTS OF β-CYCLODEXTRIN PLUS CHOLESTEROL ON PORCINE SPERM DURING COLD SHOCK

2006 ◽  
Vol 18 (2) ◽  
pp. 155 ◽  
Author(s):  
H. Galantino-Homer ◽  
W. Zeng ◽  
S. Megee ◽  
M. Modelski ◽  
I. Dobrinski
Keyword(s):  
Tyrosine Phosphorylation ◽  
Cold Shock ◽  
Cholesterol Content ◽  
Extracellular Calcium ◽  
Shock Treatment ◽  
Membrane Cholesterol ◽  
Protein Tyrosine Phosphorylation ◽  
Sperm Viability ◽  
Sperm Capacitation ◽  
Protein Tyrosine

Porcine sperm are extremely sensitive to the damaging effects of cold shock and cryopreservation. Cholesterol-binding molecules, such as 2-hydroxypropyl-�-cyclodextrin (HBCD), improve post-thaw and post-cooling porcine sperm viability when added to an egg yolk-based extender, but also enhance sperm capacitation in other species. Depending upon the environmental cholesterol content, HBCD can act either as a cholesterol shuttle or sink to increase or decrease, respectively, sperm plasma membrane cholesterol content. Increasing the sperm cholesterol to phospholipid ratio reduces cold shock sensitivity whereas decreasing the ratio initiates the process of sperm capacitation. An increase in protein tyrosine phosphorylation correlates with sperm capacitation and has been shown to be dependent upon the presence of extracellular calcium. Sperm intracellular calcium also increases during cold shock. The objective of this study was to determine the combined effects of extracellular calcium and membrane cholesterol manipulation on porcine sperm viability and protein tyrosine phosphorylation following cold shock (10�C for 10 min). Viability was assessed using CFDA/propidium iodide staining. Protein tyrosine phosphorylation, previously shown to correlate with porcine sperm capacitation, was evaluated via antiphosphotyrosine (clone 4G10) immunoblots. We report here that following cold shock, porcine sperm incubated in defined medium containing both 0.8 mM HBCD and 0.5 mM cholesterol 3-sulfate (ChS) incubated in the absence of added extracellular calcium and the presence of 6 mM EGTA have significantly improved viability (90.5 � 6.3%, n = 3) when compared with cold-shocked sperm incubated in either the same medium with calcium (46.1 � 3.8%), without HBCD or ChS (26.5 � 7.4% with calcium; 46.5 � 13.1% without calcium), or with HBCD alone (17.0 � 7.4% with calcium, 36.8 � 7.5% without calcium). As we have found previously, treatment with 0.8 mM HBCD plus 0.5 mM ChS completely inhibited the increase in protein tyrosine phosphorylation induced by the cold shock treatment. Although protein tyrosine phosphorylation correlates with porcine sperm capacitation, the ability of cold shock treatment to induce the same phosphorylation pattern indicates that other processes or pathways may contribute to its appearance. Removing extracellular calcium consistently decreased, but did not completely eliminate, the protein tyrosine phosphorylation induced by cold shock. These results indicate that cold shock-induced protein tyrosine phosphorylation is not dependent upon, but can be modulated by, extracellular calcium. The combined effects of calcium, HBCD and ChS on viability suggest that porcine sperm viability following cold shock is best maintained by removing extracellular calcium and increasing membrane cholesterol content via the cholesterol shuttle activity of HBCD. This work was supported by grants from PA Dept. Ag. (ME 443291) and the NIH (5-K08-HD041430).

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