Midbrain dopamine drives splenic immunity through a brain-to-body circuit.

Midbrain dopamine neurons are well-known to shape central nervous system function, yet there is growing evidence for their influence on the peripheral immune systems. Here we demonstrate that midbrain dopamine neurons form a circuit to the spleen via a multisynaptic pathway from the dorsal vagal complex (DVC) through the celiac ganglion. Midbrain dopamine neurons modulate the activity of D1-like and D2-like dopamine receptor-expressing DVC neurons.

'Rod and ring' formation from IMP dehydrogenase is regulated through the one-carbon metabolic pathway.

'Rods and rings' (RRs) are conserved, non-membrane-bound intracellular polymeric structures composed, in part, of inosine monophosphate dehydrogenase (IMPDH), a key enzyme leading to GMP and GTP biosynthesis. RR formation is induced by IMPDH inhibitors as well as glutamine deprivation. They also form upon treatment of cells with glutamine synthetase inhibitors.

Chemosensitizing AML cells by targeting bone marrow endothelial cells.

Refractory disease is the greatest challenge in treating patients with acute myeloid leukemia (AML). Blood vessels may serve as sanctuary sites for AML. When AML cells were co-cultured with bone marrow endothelial cells (BMECs), a greater proportion of leukemia cells were in G0/G1.

Actoclampin (+)-end-tracking motors: How the pursuit of profilin's role(s) in actin-based motility twice led to the discovery of how cells crawl.

The path to the discovery of the actoclampins began with efforts to define profilin's role in actin-based pathogen and endosome rocketing. That research identified a set of FPPPP-containing cargo proteins and FPPPP-binding proteins that are consistently stationed within the polymerization zone during episodes of active motility. The very same biophysical clues that forced us to abandon Brownian Ratchet models guided us to the Actoclampin Hypothesis, which asserts that every propulsive filament possesses a (+)-end-tracking motor that generates the forces cells need to crawl.

Angiopoietin-like protein 8 (betatrophin) is a stress-response protein that down-regulates expression of adipocyte triglyceride lipase.

Aim: Atypical angiopoietin-like 8 (ANGPTL8), also known as betatrophin, is known to regulate lipid metabolism. However, its mechanism of action remains elusive.

Methods: HepG2, 3T3-L1, and NIT-1 cells were cultured in amino acid-complete MEM or histidine-free MEM to detect ANGPTL8 expression.

Ionic Functionalization of Hydrophobic Colloidal Nanoparticles To Form Ionic Nanoparticles with Enzymelike Properties.

Inorganic colloidal nanoparticles (NPs) stabilized by a layer of hydrophobic surfactant on their surfaces have poor solubility in the aqueous phase, thus limiting their application as biosensors under physiological conditions. Here we report a simple model to ionize various types of hydrophobic colloidal NPs, including FePt, cubic Fe3O4, Pd, CdSe, and NaYF4 (Yb 30%, Er 2%, Nd 1%) NPs, to multicharged (positive and negative) NPs via ligand exchange. Surfaces of neutral hydrophobic NPs were converted to multicharged ions, thus making them soluble in water.

Activation of the Neuroprotective Angiotensin-Converting Enzyme 2 in Rat Ischemic Stroke.

The angiotensin-converting enzyme 2/angiotensin-(1-7)/Mas axis represents a promising target for inducing stroke neuroprotection. Here, we explored stroke-induced changes in expression and activity of endogenous angiotensin-converting enzyme 2 and other system components in Sprague-Dawley rats. To evaluate the clinical feasibility of treatments that target this axis and that may act in synergy with stroke-induced changes, we also tested the neuroprotective effects of diminazene aceturate, an angiotensin-converting enzyme 2 activator, administered systemically post stroke.

Glutamine deprivation initiates reversible assembly of mammalian rods and rings.

Rods and rings (RR) are protein assemblies composed of cytidine triphosphate synthetase type 1 (CTPS1) and inosine monophosphate dehydrogenase type 2 (IMPDH2), key enzymes in CTP and GTP biosynthesis. Small-molecule inhibitors of CTPS1 or IMPDH2 induce RR assembly in various cancer cell lines within 15 min to hours. Since glutamine is an essential amide nitrogen donor in these nucleotide biosynthetic pathways, glutamine deprivation was examined to determine whether it leads to RR formation.

Genetically reprogrammed, liver-derived insulin-producing cells are glucose-responsive, but susceptible to autoimmune destruction in settings of murine model of type 1 diabetes.

Many previous studies demonstrate that hepatocytes can be reprogrammed into insulin-producing cells (IPCs) utilizing viral vector-mediated delivery of pancreatic transcription factors (PTFs). However, whether these liver-derived IPCs are susceptible to autoimmune attack in animal models of type 1 diabetes remains unclear, in part due to the immunogenicity of the viral vectors used to introduce PTF genes. Adeno-associated virus serotype 2 vector-expressing Pdx1-VP16 (Pdx1) and Ngn3 were prepared and injected into the portal vein of streptozotocin (Stz)/diabetic NOD/SCID mice.

Regional citrate anticoagulation for slow continuous ultrafiltration: risk of severe metabolic alkalosis.

Background: Slow continuous ultrafiltration (SCUF) is a safe and efficient treatment for fluid overload in patients who are hemodynamically unstable, have low urine output, and are not in need of dialysis or hemofiltration for solute clearance. Sustained anticoagulation is required for these long treatments, thus posing clinically challenges for patients having contraindications to systemic anticoagulation with heparin. Regional citrate anticoagulation would be an alternative option; however, we believed that this would be problematic due to citrate kinetics that predicted the development of metabolic alkalosis.

Carbon monoxide and nitric oxide mediate cytoskeletal reorganization in microvascular cells via vasodilator-stimulated phosphoprotein phosphorylation: evidence for blunted responsiveness in diabetes.

Objective: We examined the effect of the vasoactive agents carbon monoxide (CO) and nitric oxide (NO) : n the phosphorylation and intracellular redistribution of vasodilator-stimulated phosphoprotein (VASP), a critical actin motor protein required for cell migration that also controls vasodilation and platelet aggregation.

Research Design And Methods: We examined the effect of donor-released CO and NO in endothelial progenitor cells (EPCs) and platelets from nondiabetic and diabetic subjects and in human microvascular endothelial cells (HMECs) cultured under low (5.5 mmol/l) or high (25 mmol/l) glucose conditions.

Reversal of streptozotocin-induced diabetes in mice by cellular transduction with recombinant pancreatic transcription factor pancreatic duodenal homeobox-1: a novel protein transduction domain-based therapy.

Objective: The key pancreatic transcription factor pancreatic duodenal homeobox-1 (Pdx1), known to control development and maintenance of pancreatic beta-cells, possesses a protein transduction domain (PTD) that facilitates its entry into cells. We therefore sought to evaluate the capacity of in vivo-administered recombinant Pdx1 (rPdx1) to ameliorate hyperglycemia in mice with streptozotocin-induced diabetes.

Research Design And Methods: Cell entry and transcriptional regulatory properties of rPdx1 protein and its PTD-deletion mutant rPdx1Delta protein, as well as a PTD-green fluorescent protein, were evaluated in vitro.

Guidance of actin filament elongation on filament-binding tracks.

Biomolecular motors, which convert chemical energy into mechanical work in intracellular processes, have high potential in bionanotechnology in vitro as molecular shuttles or nanoscale actuators. In this context, guided elongation of actin filaments in vitro could be used to lay tracks for myosin motor-based shuttles or to direct nanoscale actuators based on actin filament end-tracking motors. To guide the direction of filament polymerization on surfaces, microcontact printing was used to create tracks of chemically modified myosin, which binds to, but cannot exert force on, filaments.

Nematode sperm motility: nonpolar filament polymerization mediated by end-tracking motors.

In nematode sperm cell motility, major sperm protein (MSP) filament assembly results in dynamic membrane protrusions in a manner that closely resembles actin-based motility in other eukaryotic cells. Paradoxically, whereas actin-based motility is driven by addition of ATP-bound actin subunits onto actin filament plus-ends located at the cell membrane, MSP dimers assemble from solution into nonpolar filaments that lack a nucleotide binding site. Thus, filament polarity and on-filament ATP hydrolysis, although essential for actin-based motility, appear to be unnecessary for membrane protrusions by MSP.

Diffusion rate limitations in actin-based propulsion of hard and deformable particles.

The mechanism by which actin polymerization propels intracellular vesicles and invasive microorganisms remains an open question. Several recent quantitative studies have examined propulsion of biomimetic particles such as polystyrene microspheres, phospholipid vesicles, and oil droplets. In addition to allowing quantitative measurement of parameters such as the dependence of particle speed on its size, these systems have also revealed characteristic behaviors such a saltatory motion of hard particles and oscillatory deformation of soft particles.

Structural insights into Alzheimer filament assembly pathways based on site-directed mutagenesis and S-glutathionylation of three-repeat neuronal Tau protein.

Although Tau and MAP2 readily assemble into straight filaments (SFs), Tau's unique ability to form paired-helical filaments (PHFs) may offer clues as to why Tau's microtubule-binding region (MTBR) is the exclusive building block of the neurofibrillary tangles that accumulate during Alzheimer's disease. To learn more about the factors permitting Tau to form both SFs and PHFs, we investigated the microtubule binding, thiol oxidation, and polymerization reactions of the monomer and dimer forms of Tau and MAP2 MTBRs. This review focuses on electron microscopic evidence (1) that facilitated the identification of amino acid residues within 3-repeat Tau that promote PHF formation; and (2) provided experimental evidence for the polymerization of S-glutathionylated three-repeat Tau, a reaction that unambiguously demonstrates that disulfide-linked Tau-S-S-Tau dimer formation is not a compulsory step in filament assembly.

Listeria's right-handed helical rocket-tail trajectories: mechanistic implications for force generation in actin-based motility.

Listeria monocytogenes forms right-handed helical rocket tail trajectories during actin-based motility in cell-free extracts, and this stereochemical feature is consistent with actoclampin's affinity-modulated, clamped-filament elongation model [Dickinson and Purich, 2002: Biophys J 82:605-617]. In that mechanism, right-handed torque is generated by an end-tracking molecular motor, each comprised of a filament barbed end and clamping protein that processively traces the right-handed helix of its filament partner. By contrast, torque is not a predicted property of those models (e.

Force generation by cytoskeletal filament end-tracking proteins.

Force generation in several types of cell motility is driven by rapidly elongating cytoskeletal filaments that are persistently tethered at their polymerizing ends to propelled objects. These properties are not easily explained by force-generation models that require free (i.e.

Actin-based endosome and phagosome rocketing in macrophages: activation by the secretagogue antagonists lanthanum and zinc.

Although motile endocytic vesicles form actin-rich rocket tails [Merrifield et al., 1999: Nature Cell Biol 1:72-74], the mechanism of intracellular organelle locomotion remains poorly understood. We now demonstrate that bone marrow macrophages treated with lanthanum and zinc ions, well-known secretagogue antagonists, reliably exhibit vesicle motility.

A direct-transfer polymerization model explains how the multiple profilin-binding sites in the actoclampin motor promote rapid actin-based motility.

The high actin-based motility rates observed in nonmuscle cells require the per-second addition of 400-500 monomers to the barbed ends of growing actin filaments. The chief polymerization-competent species is profilin.actin.

Actin-based phagosome motility.

Despite abundant evidence of actin's involvement at the particle internalization stage of phagocytosis, little is known about whether phagosomes undergo the same type of actin-based motility as observed with endocytic vesicles or such intracellular pathogens as Listeria and Shigella. By employing video microscopy to follow the fate of latex bead-containing phagosomes within the cytoplasm of bone marrow macrophages, we have made the novel observation of actin-based phagosome motility. Immunofluorescence microscopy confirmed that phagosomes containing IgG-opsonized, bovine serum albumin (or BSA) -coated or uncoated latex beads all formed actin-rich rocket tails that persisted only during a brief, 1-2 min period of actin-based motility.

In vitro assembly of Alzheimer-like filaments. How a small cluster of charged residues in Tau and MAP2 controls filament morphology.

Although the microtubule-binding regions (MTBRs) of both Tau and MAP2 can undergo self-assembly into straight filaments (SFs) in vitro, only the Tau MTBR forms paired helical filaments (PHFs). Moreover, Tau appears to be the exclusive building block of the neuropathic filaments observed in Alzheimer's disease and certain frontotemporal dementias (FTDs). Despite significant conservation in the MTBR sequences, there are two persistently different stretches of amino acids (designated here as Module-A and Module-B) between Tau and MAP2 from a number of organisms.