SR-B1 drives endothelial cell LDL transcytosis via DOCK4 to promote atherosclerosis.

Atherosclerosis, which underlies life-threatening cardiovascular disorders such as myocardial infarction and stroke, is initiated by passage of low-density lipoprotein (LDL) cholesterol into the artery wall and its engulfment by macrophages, which leads to foam cell formation and lesion development. It is unclear how circulating LDL enters the artery wall to instigate atherosclerosis. Here we show in mice that scavenger receptor class B type 1 (SR-B1) in endothelial cells mediates the delivery of LDL into arteries and its accumulation by artery wall macrophages, thereby promoting atherosclerosis.

Distinct reorganization of collagen architecture in lipopolysaccharide-mediated premature cervical remodeling.

Previous work has identified divergent mechanisms by which cervical remodeling is achieved in preterm birth (PTB) induced by hormone withdrawal (mifepristone) or lipopolysaccharide (LPS). Our current study aims to document how collagen architecture is modified to achieve premature cervical remodeling in mice treated with LPS as a model of infection-induced inflammation. Cervices were collected on gestation day (d) 15 from mice with premature cervical ripening induced by LPS and compared to d15 and d18 controls as well as a hormone withdrawal PTB model.

Soluble klotho binds monosialoganglioside to regulate membrane microdomains and growth factor signaling.

Soluble klotho, the shed ectodomain of the antiaging membrane protein α-klotho, is a pleiotropic endocrine/paracrine factor with no known receptors and poorly understood mechanism of action. Soluble klotho down-regulates growth factor-driven PI3K signaling, contributing to extension of lifespan, cardioprotection, and tumor inhibition. Here we show that soluble klotho binds membrane lipid rafts.

Brown adipose tissue derived VEGF-A modulates cold tolerance and energy expenditure.

We recently reported that local overexpression of VEGF-A in white adipose tissue (WAT) protects against diet-induced obesity and metabolic dysfunction. The observation that VEGF-A induces a "brown adipose tissue (BAT)-like" phenotype in WAT prompted us to further explore the direct function of VEGF-A in BAT. We utilized a doxycycline (Dox)-inducible, brown adipocyte-specific VEGF-A transgenic overexpression model to assess direct effects of VEGF-A in BAT in vivo.

Autophagy is essential for cardiac morphogenesis during vertebrate development.

Genetic analyses indicate that autophagy, an evolutionarily conserved lysosomal degradation pathway, is essential for eukaryotic differentiation and development. However, little is known about whether autophagy contributes to morphogenesis during embryogenesis. To address this question, we examined the role of autophagy in the early development of zebrafish, a model organism for studying vertebrate tissue and organ morphogenesis.

The physical chemistry of cytoplasm and its influence on cell function: an update.

From the point of view of intermolecular interactions, the cytoplasmic space is more like a crowded party in a house full of furniture than a game of tag in an empty field. Understanding the physical chemical properties of cytoplasm is thus of key importance for understanding cellular function. This article attempts to provide an entrée into the current literature on this subject and offers some general guidelines for thinking about intracellular biochemistry.

Quantitative fluorescence imaging reveals point of release for lipoproteins during LDLR-dependent uptake.

The LDL receptor (LDLR) supports efficient uptake of both LDL and VLDL remnants by binding lipoprotein at the cell surface, internalizing lipoprotein through coated pits, and releasing lipoprotein in endocytic compartments before returning to the surface for further rounds of uptake. While many aspects of lipoprotein binding and receptor entry are well understood, it is less clear where, when, and how the LDLR releases lipoprotein. To address these questions, the current study employed quantitative fluorescence imaging to visualize the uptake and endosomal processing of LDL and the VLDL remnant β-VLDL.

Subcellular particles tracking in time-lapse confocal microscopy images.

Automatically tracking and analyzing the mobility of live subcellular structures will expedite the understanding of signaling pathways, protein-protein interaction, drug delivery, protein synthesis and functionality. Traditional computer vision tracking methods produce yet-to-be-satisfactory results due to the complexity of the particles recorded in spatial-temporal video sequences from confocal images. The difficulties arise from diverse modalities of motion patterns (translational, Brownian, or sessile), changes in behavior during tracking, and cluttered background.

Regulation of purinergic signaling in biliary epithelial cells by exocytosis of SLC17A9-dependent ATP-enriched vesicles.

ATP in bile is a potent secretogogue, stimulating biliary epithelial cell (BEC) secretion through binding apical purinergic receptors. In response to mechanosensitive stimuli, BECs release ATP into bile, although the cellular basis of ATP release is unknown. The aims of this study in human and mouse BECs were to determine whether ATP release occurs via exocytosis of ATP-enriched vesicles and to elucidate the potential role of the vesicular nucleotide transporter SLC17A9 in purinergic signaling.

Epicardial spindle orientation controls cell entry into the myocardium.

During heart morphogenesis, epicardial cells undergo an epithelial-to-mesenchymal transition (EMT) and migrate into the subepicardium. The cellular signals controlling this process are poorly understood. Here, we show that epicardial cells exhibit two distinct mitotic spindle orientations, directed either parallel or perpendicular to the basement membrane.

Initiation of purinergic signaling by exocytosis of ATP-containing vesicles in liver epithelium.

Extracellular ATP represents an important autocrine/paracrine signaling molecule within the liver. The mechanisms responsible for ATP release are unknown, and alternative pathways have been proposed, including either conductive ATP movement through channels or exocytosis of ATP-enriched vesicles, although direct evidence from liver cells has been lacking. Utilizing dynamic imaging modalities (confocal and total internal reflection fluorescence microscopy and luminescence detection utilizing a high sensitivity CCD camera) at different scales, including confluent cell populations, single cells, and the intracellular submembrane space, we have demonstrated in a model liver cell line that (i) ATP release is not uniform but reflects point source release by a defined subset of cells; (ii) ATP within cells is localized to discrete zones of high intensity that are approximately 1 mum in diameter, suggesting a vesicular localization; (iii) these vesicles originate from a bafilomycin A(1)-sensitive pool, are depleted by hypotonic exposure, and are not rapidly replenished from recycling of endocytic vesicles; and (iv) exocytosis of vesicles in response to cell volume changes depends upon a complex series of signaling events that requires intact microtubules as well as phosphoinositide 3-kinase and protein kinase C.

Dynamic near-infrared optical imaging of 2-deoxyglucose uptake by intracranial glioma of athymic mice.

Background: It is recognized that cancer cells exhibit highly elevated glucose metabolism compared to non-tumor cells. We have applied in vivo optical imaging to study dynamic uptake of a near-infrared dye-labeled glucose analogue, 2-deoxyglucose (2-DG) by orthotopic glioma in a mouse model.

Methodology And Principal Findings: The orthotopic glioma model was established by surgically implanting U87-luc glioma cells into the right caudal nuclear area of nude mice.

Tracking multiple interacting subcellular structure by sequential Monte Carlo method.

With the wide application of Green Fluorescent Proteins (GFP) in the study of live cells, there is a surging need for computer-aided analysis on the huge amount of image sequence data acquired by the advanced microscopy devices. In this paper, a framework based on Sequential Monte Carlo (SMC) is proposed for multiple interacting object tracking. The distribution of the dimension varying joint state is sampled efficiently by a Reversible Jump Markov Chain Monte Carlo (RJMCMC) algorithm with a novel height swap move.

Systemic fate of the adipocyte-derived factor adiponectin.

Objective: The adipocyte-derived secretory protein adiponectin has been widely studied and shown to have potent insulin-sensitizing, antiapoptotic, and anti-inflammatory properties. While its biosynthesis is well understood, its fate, once in circulation, is less well established.

Research Design And Methods: Here, we examine the half-life of adiponectin in circulation by tracking fluorescently labeled recombinant adiponectin in the circulation, following it to its final destination in the hepatocyte.

Feature selection, matching, and evaluation for subcellular structure tracking.

Understanding the motility of subcellular particles like organelles, vesicles, or mRNAs is critical to understand how cells regulate delivery of specific proteins from the site of synthesis to the site of action. The goal of this paper is to present a framework of feature selection, matching, and evaluation for the segmentation and tracking of green fluorescent protein (GFP) labeled subcellular structures. To select stable and distinctive features for small-sized subcellular particles, a grid-based minimum variance (GMV) feature selection method is proposed.

Autophagy gene-dependent clearance of apoptotic cells during embryonic development.

Autophagy is commonly observed in metazoan organisms during programmed cell death (PCD), but its function in dying cells has been unclear. We studied the role of autophagy in embryonic cavitation, the earliest PCD process in mammalian development. Embryoid bodies (EBs) derived from cells lacking the autophagy genes, atg5 or beclin 1, fail to cavitate.

Dectin-2 is a pattern recognition receptor for fungi that couples with the Fc receptor gamma chain to induce innate immune responses.

Antigen presenting cells recognize pathogens via pattern recognition receptors (PRR), which upon ligation transduce intracellular signals that can induce innate immune responses. Because some C-type lectin-like receptors (e.g.

Mitochondria mass is low in mouse substantia nigra dopamine neurons: implications for Parkinson's disease.

In Parkinson's disease (PD) there is a selective loss of certain midbrain dopaminergic (DA) neurons. The most vulnerable neurons reside in the substantia nigra zona compacta (SNC), whereas the DA neurons in the ventral tegmental area (VTA) and interfascicular (IF) nucleus are less vulnerable to degeneration. Many sporadic PD patients have a defect in mitochondria respiration, and some of the genes that cause PD are mitochondrial-related (e.

WNK1 phosphorylates synaptotagmin 2 and modulates its membrane binding.

WNK (with no lysine [K]) protein kinases were named for their unique active site organization. Mutations in WNK1 and WNK4 cause a familial form of hypertension by undefined mechanisms. Here, we report that WNK1 selectively binds to and phosphorylates synaptotagmin 2 (Syt2) within its calcium binding C2 domains.

ERK2 enters the nucleus by a carrier-independent mechanism.

In stimulated cells, the mitogen-activated protein kinase ERK2 (extracellular signal-regulated kinase 2) concentrates in the nucleus. Evidence exists for CRM1-dependent, mitogen-activated protein kinase kinase-mediated nuclear export of ERK2, but its mechanism of nuclear entry is not understood. To determine requirements for nuclear transport, we tagged ERK2 with green fluorescent protein (GFP) and examined its nuclear uptake by using an in vitro import assay.