Sex-Specific Variances in Anatomy and Blood Flow of the Left Main Coronary Bifurcation: Implications for Coronary Artery Disease Risk

Studies have shown marked sex disparities in Coronary Artery Diseases (CAD) epidemiology, yet the underlying mechanisms remain unclear. We explored sex disparities in the coronary anatomy and the resulting haemodynamics in patients with suspected, but no significant CAD. Left Main (LM) bifurcations were reconstructed from CTCA images of 127 cases (42 males and 85 females, aged 38 to 81). Detailed shape parameters were measured for comparison, including bifurcation angles, curvature, and diameters, before solving the haemodynamic metrics using CFD. The severity and location of the normalised vascular area exposed to physiologically adverse haemodynamics were statistically compared between sexes for all branches. We found significant differences between sexes in potentially adverse haemodynamics. Females were more likely than males to exhibit adversely low Time Averaged Endothelial Shear Stress along the inner wall of a bifurcation (16.8% vs. 10.7%). Males had a higher percentage of areas exposed to both adversely high Relative Residence Time (6.1% vs 4.2%, p=0.001) and high Oscillatory Shear Index (4.6% vs 2.3%, p<0.001). However, the OSI values were generally small and should be interpreted cautiously. Males had larger arteries (M vs F, LM: 4.0mm vs 3.3mm, LAD: 3.6mm 3.0mm, LCX:3.5mm vs 2.9mm), and females exhibited higher curvatures in all three branches (M vs F, LM: 0.40 vs 0.46, LAD: 0.45 vs 0.51, LCx: 0.47 vs 0.55, p<0.001) and larger inflow angle of the LM trunk (M: 12.9{\deg} vs F: 18.5{\deg}, p=0.025). Haemodynamic differences were found between male and female patients, which may contribute, at least in part, to differences in CAD risk. This work may facilitate a better understanding of sex differences in the clinical presentation of CAD, contributing to improved sex-specific screening, especially relevant for women with CAD who currently have worse predictive outcomes.Comment: 14 pages, 5 figure

Quantitative control of protein S-palmitoylation regulates meiotic entry in fission yeast

International audienceProtein S-palmitoylation, a lipid modification mediated by members of the palmitoyltransferase family, serves as an important membrane-targeting mechanism in eukaryotes. Although changes in palmitoyltransferase expression are associated with various physiological and disease states, how these changes affect global protein palmitoylation and cellular function remains unknown. Using a bioorthogonal chemical reporter and labeling strategy to identify and analyze multiple cognate substrates of a single Erf2 palmitoyltransferase, we demonstrate that control of Erf2 activity levels underlies the differential modification of key substrates such as the Rho3 GTPase in vegetative and meiotic cells. We show further that modulation of Erf2 activity levels drives changes in the palmitoylome as cells enter meiosis and affects meiotic entry. Disruption of Erf2 function delays meiotic entry, while increasing Erf2 palmitoyltransferase activity triggers aberrant meiosis in sensitized cells. Erf2-induced meiosis requires the function of the Rho3 GTPase, which is regulated by its palmitoylation state. We propose that control of palmitoyltransferase activity levels provides a fundamental mechanism for modulating palmitoylomes and cellular functions

Polen

Polen : Land in der Mitte Europas : Exkursionsbericht / [Hrsg.: Rudolf Schönbach ...] - Augsburg, 1977. - 115 S

Quantitative control of protein palmitoylation by varying palmitoyltransferase levels affects meiotic entry.

<p>(A) Labels are indicated in box. qPCR analysis of <i>erf2</i> and <i>erf4</i> transcripts normalized to <i>act1</i> mRNA levels in indicated <i>pat1-114/pat1-114</i> strains 8 h into synchronous meiosis (top panel). Data represent mean values of experimental triplicates ± SD Palmitoylation of cognate Erf2 substrates were analyzed from the same lysate of each strain (bottom panels). Ras1 and Rho3-HA₃ were immunopurified and their levels were determined by Ras1 and HA immunoblots, respectively. Isp3 palmitoylation was monitored at the lysate level since it accounts for most of the fluorescence at ∼23 kDa. (B) Labels are indicated in box. Overexpression of <i>erf2</i> and/or <i>erf4</i> from thiamine-repressible <i>nmt</i> promoters in the indicated vegetatively growing <i>pat1-114</i> cells was achieved by switching them into thiamine-free medium for 24 h. qPCR analysis (top panel) as well as palmitoylation of Ras1 and Rho3 (bottom panels) were performed as described in (A). Isp3 is not expressed in vegetative cells. Cells were maintained at permissive temperature throughout this experiment. (C, D) DAPI (left) and DIC (right) images of indicated cells 96 h after <i>erf2</i> and/or <i>erf4</i> overexpression. The DHHC→DHHA catalytic <i>erf2</i> mutant was co-overexpressed with <i>erf4</i> from <i>nmt1</i> promoters. Scale bars, 10 µm.</p

Modeling Sporadic Alzheimer's Disease in Human Brain Organoids under Serum Exposure.

Alzheimer's disease (AD) is a progressive neurodegenerative disease with no cure. Huge efforts have been made to develop anti-AD drugs in the past decades. However, all drug development programs for disease-modifying therapies have failed. Possible reasons for the high failure rate include incomplete understanding of complex pathophysiology of AD, especially sporadic AD (sAD), and species difference between humans and animal models used in preclinical studies. In this study, sAD is modeled using human induced pluripotent stem cell (hiPSC)-derived 3D brain organoids. Because the blood-brain barrier (BBB) leakage is a well-known risk factor for AD, brain organoids are exposed to human serum to mimic the serum exposure consequence of BBB breakdown in AD patient brains. The serum-exposed brain organoids are able to recapitulate AD-like pathologies, including increased amyloid beta (Aβ) aggregates and phosphorylated microtubule-associated tau protein (p-Tau) level, synaptic loss, and impaired neural network. Serum exposure increases Aβ and p-Tau levels through inducing beta-secretase 1 (BACE) and glycogen synthase kinase-3 alpha / beta (GSK3α/β) levels, respectively. In addition, single-cell transcriptomic analysis of brain organoids reveals that serum exposure reduced synaptic function in both neurons and astrocytes and induced immune response in astrocytes. The human brain organoid-based sAD model established in this study can provide a powerful platform for both mechanistic study and therapeutic development in the future

Erf2 substrates are differentially modified in vegetative and meiotic cells.

<p>(A) Filter criteria for candidate substrates that are palmitoylated by Erf2 during meiosis. (B) Each of the 238 candidates obtained is represented as a data point reflecting its molecular weight and enrichment (net spectral counts) in alk-16 over DMSO labeled <i>erf2⁺</i> meiotic cells. Isp3 and Rho3 are the top two candidates with molecular weights ∼23 kDa (shaded). (C) Fluorescence profiles of meiotic cells with indicated gene deletions or expressing endogenous or tagged Isp3 (top panels). Western blot is probed for HA (bottom panels). Ctrl, DMSO control. (D) Isp3-HA₃ expression as determined by anti-HA blot of lysates from cells in distinct cellular states. Veg, vegetative cells. Mei, meiotic cells. (E) Rho3-HA₃ palmitoylation in meiotic <i>erf2⁺</i> and <i>erf2Δ</i> cells (top panel). Western blot is probed for HA (bottom panel). (F) Ras1 and Rho3 palmitoylation states in vegetative and meiotic cells (top panels). Western blots were probed for Ras1 and HA (bottom panels). Synchronous meiosis in indicated diploid <i>pat1-114/pat1-114</i> cells was induced by shifting nitrogen-starved cultures to restrictive temperature (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001597#s4" target="_blank">Materials and Methods</a>). Meiotic cells refer to cells 8 h after the temperature shift.</p

Palmitoylation-dependent Rho3 function is required for the Erf2-induced meiotic phenotype.

<p>(A) DAPI (top) and DIC (bottom) images of <i>erf2</i> and <i>erf4</i> co-overexpressing cells with indicated genotypes at 96 h postinduction. Vectors expressing internally tagged wild-type and mutant (Cys4→Ala) Rho3-HA₃ proteins from the <i>nmt41</i> promoter were integrated into the chromosome of <i>rho3Δ</i> cells. Scale bars, 10 µm. (B) Alk-16-associated fluorescence of Rho3 and palmitoylation-deficient Rho3(C4A) (top panel). Western blots were probed for HA (bottom panel).</p

The Erf2–Erf4 palmitoyltransferase drives major changes in the meiotic palmitoylome during meiosis.

<p>(A–B) Alk-16-associated fluorescence of immunopurified Ras1 from vegetatively growing cells with the indicated palmitoyltransferase deletions (top panels). Western blots are probed for Ras1 (bottom panels). Wild-type (<i>DHHC</i>) or catalytically inactive (<i>DHHA</i>) Erf2 was expressed from a thiamine-repressible promoter in <i>erf2Δ</i> cells (B). (C) Fluorescence detection of palmitoylated substrates (top panel) and Ras1 palmitoylation (bottom panel) in homozygous diploid <i>pat1-114/pat1-114</i> cells with the indicated palmitoyltransferase deletions 8 h after meiotic induction. Ctrl, DMSO control; Veg, vegetative cells.</p