High-mannose glycans from Schistosoma mansoni eggs are important for priming of Th2 responses via Dectin-2 and prostaglandin E2.

The parasitic helminth Schistosoma mansoni is a potent inducer of type 2 immune responses by stimulating dendritic cells (DCs) to prime T helper 2 (Th2) responses. We previously found that S. mansoni soluble egg antigens (SEA) promote the synthesis of Prostaglandin E2 (PGE2) by DCs through ERK-dependent signaling via Dectin-1 and Dectin-2 that subsequently induces OX40L expression, licensing them for Th2 priming, yet the ligands present in SEA involved in driving this response and whether specific targeting of PGE2 synthesis by DCs could affect Th2 polarization are unknown. We here show that the ability of SEA to bind Dectin-2 and drive ERK phosphorylation, PGE2 synthesis, OX40L expression, and Th2 polarization is impaired upon cleavage of high-mannose glycans by Endoglycosidase H treatment. This identifies high-mannose glycans present on glycoproteins in SEA as important drivers of this signaling axis. Moreover, we find that OX40L expression and Th2 induction are abrogated when microsomal prostaglandin E synthase-1 (mPGES) is selectively inhibited, but not when a general COX-1/2 inhibitor is used. This shows that the de novo synthesis of PGE2 is vital for the Th2 priming function of SEA-stimulated DCs as well as points to the potential existence of other COX-dependent lipid mediators that antagonize PGE2-driven Th2 polarization. Lastly, specific PGE2 inhibition following immunization with S. mansoni eggs dampened the egg-specific Th cell response. In summary, our findings provide new insights in the molecular mechanisms underpinning Th2 induction by S. mansoni and identify druggable targets for potential control of helminth driven-Th2 responses.

Dendritic cell-intrinsic LKB1-AMPK/SIK signaling controls metabolic homeostasis by limiting the hepatic Th17 response during obesity.

Obesity-associated metabolic inflammation drives the development of insulin resistance and type 2 diabetes, notably through modulating innate and adaptive immune cells in metabolic organs. The nutrient sensor liver kinase B1 (LKB1) has recently been shown to control cellular metabolism and T cell priming functions of DCs. Here, we report that hepatic DCs from high-fat diet-fed (HFD-fed) obese mice display increased LKB1 phosphorylation and that LKB1 deficiency in DCs (CD11cΔLKB1) worsened HFD-driven hepatic steatosis and impaired glucose homeostasis. Loss of LKB1 in DCs was associated with increased expression of Th17-polarizing cytokines and accumulation of hepatic IL-17A+ Th cells in HFD-fed mice. Importantly, IL-17A neutralization rescued metabolic perturbations in HFD-fed CD11cΔLKB1 mice. Mechanistically, deficiency of the canonical LKB1 target AMPK in HFD-fed CD11cΔAMPKα1 mice recapitulated neither the hepatic Th17 phenotype nor the disrupted metabolic homeostasis, suggesting the involvement of other and/or additional LKB1 downstream effectors. We indeed provide evidence that the control of Th17 responses by DCs via LKB1 is actually dependent on both AMPKα1 salt-inducible kinase signaling. Altogether, our data reveal a key role for LKB1 signaling in DCs in protection against obesity-induced metabolic dysfunctions by limiting hepatic Th17 responses.

ER stress promotes mitochondrial DNA mediated type-1 interferon response in beta-cells and interleukin-8 driven neutrophil chemotaxis.

Beta-cell destruction in type 1 diabetes (T1D) results from the combined effect of inflammation and recurrent autoimmunity. Accumulating evidence suggests the engagement of cellular stress during the initial stage of the disease, preceding destruction and triggering immune cell infiltration. While the role of the endoplasmic reticulum (ER) in this process has been largely described, the participation of the other cellular organelles, particularly the mitochondria which are central mediator for beta-cell survival and function, remains poorly investigated. Here, we have explored the contribution of ER stress, in activating type-I interferon signaling and innate immune cell recruitment. Using human beta-cell line EndoC-ßH1 exposed to thapsigargin, we demonstrate that induction of cellular stress correlates with mitochondria dysfunction and a significant accumulation of cytosolic mitochondrial DNA (mtDNA) that triggers neutrophils migration by an IL8-dependent mechanism. These results provide a novel mechanistic insight on how ER stress can cause insulitis and may ultimately facilitate the identification of potential targets to protect beta-cells against immune infiltration.

mTORC1 signaling in antigen-presenting cells of the skin restrains CD8+ T cell priming.

How mechanistic target of rapamycin complex 1 (mTORC1), a key regulator of cellular metabolism, affects dendritic cell (DC) metabolism and T cell-priming capacity has primarily been investigated in vitro, but how mTORC1 regulates this in vivo remains poorly defined. Here, using mice deficient for mTORC1 component raptor in DCs, we find that loss of mTORC1 negatively affects glycolytic and fatty acid metabolism and maturation of conventional DCs, particularly cDC1s. Nonetheless, antigen-specific CD8+ T cell responses to infection are not compromised and are even enhanced following skin immunization. This is associated with increased activation of Langerhans cells and a subpopulation of EpCAM-expressing cDC1s, of which the latter show an increased physical interaction with CD8+ T cells in situ. Together, this work reveals that mTORC1 limits CD8+ T cell priming in vivo by differentially orchestrating the metabolism and immunogenicity of distinct antigen-presenting cell subsets, which may have implications for clinical use of mTOR inhibitors.

On the force field optimisation of [Formula: see text]-lactam cores using the force field Toolkit.

When employing molecular dynamics (MD) simulations for computer-aided drug design, the quality of the used force fields is highly important. Here we present reparametrisations of the force fields for the core molecules from 9 different [Formula: see text]-lactam classes, for which we utilized the force field Toolkit and Gaussian calculations. We focus on the parametrisation of the dihedral angles, with the goal of reproducing the optimised quantum geometry in MD simulations. Parameters taken from CGenFF turn out to be a good initial guess for the multiplicity of each dihedral angle, but the key to a successful parametrisation is found to lie in the phase shifts. Based on the optimised quantum geometry, we come up with a strategy for predicting the phase shifts prior to the dihedral potential fitting. This allows us to successfully parameterise 8 out of the 11 molecules studied here, while the remaining 3 molecules can also be parameterised with small adjustments. Our work highlights the importance of predicting the dihedral phase shifts in the ligand parametrisation protocol, and provides a simple yet valuable strategy for improving the process of parameterising force fields of drug-like molecules.

Effects of a novel polyphenol-rich plant extract on body composition, inflammation, insulin sensitivity, and glucose homeostasis in obese mice.

BACKGROUND/OBJECTIVES: The worldwide prevalence of obesity, metabolic syndrome and type 2 diabetes (T2D) is reaching epidemic proportions that urge the development of new management strategies. Totum-63 is a novel, plant-based polyphenol-rich active principle that has been shown to reduce body weight, fasting glycemia, glucose intolerance, and fatty liver index in obese subjects with prediabetes. Here, we investigated the effects and underlying mechanism(s) of Totum-63 on metabolic homeostasis in insulin-resistant obese mice. METHODS: Male C57Bl6/J mice were fed a high-fat diet for 12 weeks followed by supplementation with Totum-63 for 4 weeks. The effects on whole-body energy and metabolic homeostasis, as well as on tissue-specific inflammation and insulin sensitivity were assessed using a variety of immunometabolic phenotyping tools. RESULTS: Totum-63 decreased body weight and fat mass in obese mice, without affecting lean mass, food intake and locomotor activity, and increased fecal energy excretion and whole-body fatty acid oxidation. Totum-63 reduced fasting plasma glucose, insulin and leptin levels, and improved whole-body insulin sensitivity and peripheral glucose uptake. The expression of insulin receptor ß and the insulin-induced phosphorylation of Akt/PKB were increased in liver, skeletal muscle, white adipose tissue (WAT) and brown adipose tissue (BAT). Hepatic steatosis was also decreased by Totum-63 and associated with a lower expression of genes involved in fatty acid uptake, de novo lipogenesis, inflammation, and fibrosis. Furthermore, a significant reduction in pro-inflammatory macrophages was also observed in epidydimal WAT. Finally, a potent decrease in BAT mass associated with enhanced tissue expression of thermogenic genes was found, suggesting BAT activation by Totum-63. CONCLUSIONS: Our results show that Totum-63 reduces inflammation and improves insulin sensitivity and glucose homeostasis in obese mice through pleiotropic effects on various metabolic organs. Altogether, plant-derived Totum-63 might constitute a promising novel nutritional supplement for alleviating metabolic dysfunctions in obese people with or without T2D.

Myeloid ATP Citrate Lyase Regulates Macrophage Inflammatory Responses In Vitro Without Altering Inflammatory Disease Outcomes.

Macrophages are highly plastic, key regulators of inflammation. Deregulation of macrophage activation can lead to excessive inflammation as seen in inflammatory disorders like atherosclerosis, obesity, multiple sclerosis and sepsis. Targeting intracellular metabolism is considered as an approach to reshape deranged macrophage activation and to dampen the progression of inflammatory disorders. ATP citrate lyase (Acly) is a key metabolic enzyme and an important regulator of macrophage activation. Using a macrophage-specific Acly-deficient mouse model, we investigated the role of Acly in macrophages during acute and chronic inflammatory disorders. First, we performed RNA sequencing to demonstrate that Acly-deficient macrophages showed hyperinflammatory gene signatures in response to acute LPS stimulation in vitro. Next, we assessed endotoxin-induced peritonitis in myeloid-specific Acly-deficient mice and show that, apart from increased splenic Il6 expression, systemic and local inflammation were not affected by Acly deficiency. Also during obesity, both chronic low-grade inflammation and whole-body metabolic homeostasis remained largely unaltered in mice with Acly-deficient myeloid cells. Lastly, we show that macrophage-specific Acly deletion did not affect the severity of experimental autoimmune encephalomyelitis (EAE), an experimental model of multiple sclerosis. These results indicate that, despite increasing inflammatory responses in vitro, macrophage Acly deficiency does not worsen acute and chronic inflammatory responses in vivo. Collectively, our results indicate that caution is warranted in prospective long-term treatments of inflammatory disorders with macrophage-specific Acly inhibitors. Together with our earlier observation that myeloid Acly deletion stabilizes atherosclerotic lesions, our findings highlight that therapeutic targeting of macrophage Acly can be beneficial in some, but not all, inflammatory disorders.

The helminth glycoprotein omega-1 improves metabolic homeostasis in obese mice through type 2 immunity-independent inhibition of food intake.

Type 2 immunity plays an essential role in the maintenance of metabolic homeostasis and its disruption during obesity promotes meta-inflammation and insulin resistance. Infection with the helminth parasite Schistosoma mansoni and treatment with its soluble egg antigens (SEA) induce a type 2 immune response in metabolic organs and improve insulin sensitivity and glucose tolerance in obese mice, yet, a causal relationship remains unproven. Here, we investigated the effects and underlying mechanisms of the T2 ribonuclease omega-1 (ω1), one of the major S mansoni immunomodulatory glycoproteins, on metabolic homeostasis. We show that treatment of obese mice with plant-produced recombinant ω1, harboring similar glycan motifs as present on the native molecule, decreased body fat mass, and improved systemic insulin sensitivity and glucose tolerance in a time- and dose-dependent manner. This effect was associated with an increase in white adipose tissue (WAT) type 2 T helper cells, eosinophils, and alternatively activated macrophages, without affecting type 2 innate lymphoid cells. In contrast to SEA, the metabolic effects of ω1 were still observed in obese STAT6-deficient mice with impaired type 2 immunity, indicating that its metabolic effects are independent of the type 2 immune response. Instead, we found that ω1 inhibited food intake, without affecting locomotor activity, WAT thermogenic capacity or whole-body energy expenditure, an effect also occurring in leptin receptor-deficient obese and hyperphagic db/db mice. Altogether, we demonstrate that while the helminth glycoprotein ω1 can induce type 2 immunity, it improves whole-body metabolic homeostasis in obese mice by inhibiting food intake via a STAT6-independent mechanism.

LKB1 expressed in dendritic cells governs the development and expansion of thymus-derived regulatory T cells.

Liver Kinase B1 (LKB1) plays a key role in cellular metabolism by controlling AMPK activation. However, its function in dendritic cell (DC) biology has not been addressed. Here, we find that LKB1 functions as a critical brake on DC immunogenicity, and when lost, leads to reduced mitochondrial fitness and increased maturation, migration, and T cell priming of peripheral DCs. Concurrently, loss of LKB1 in DCs enhances their capacity to promote output of regulatory T cells (Tregs) from the thymus, which dominates the outcome of peripheral immune responses, as suggested by increased resistance to asthma and higher susceptibility to cancer in CD11cΔLKB1 mice. Mechanistically, we find that loss of LKB1 specifically primes thymic CD11b+ DCs to facilitate thymic Treg development and expansion, which is independent from AMPK signalling, but dependent on mTOR and enhanced phospholipase C ß1-driven CD86 expression. Together, our results identify LKB1 as a critical regulator of DC-driven effector T cell and Treg responses both in the periphery and the thymus.

Isolated Schistosoma mansoni eggs prevent allergic airway inflammation.

Chronic helminth infection with Schistosoma (S.) mansoni protects against allergic airway inflammation (AAI) in mice and is associated with reduced Th2 responses to inhaled allergens in humans, despite the presence of schistosome-specific Th2 immunity. Schistosome eggs strongly induce type 2 immunity and allow to study the dynamics of Th2 versus regulatory responses in the absence of worms. Treatment with isolated S. mansoni eggs by i.p. injection prior to induction of AAI to ovalbumin (OVA)/alum led to significantly reduced AAI as assessed by less BAL and lung eosinophilia, less cellular influx into lung tissue, less OVA-specific Th2 cytokines in lungs and lung-draining mediastinal lymph nodes and less circulating allergen-specific IgG1 and IgE antibodies. While OVA-specific Th2 responses were inhibited, treatment induced a strong systemic Th2 response to the eggs. The protective effect of S. mansoni eggs was unaltered in µMT mice lacking mature (B2) B cells and unaffected by Treg cell depletion using anti-CD25 blocking antibodies during egg treatment and allergic sensitization. Notably, prophylactic egg treatment resulted in a reduced influx of pro-inflammatory, monocyte-derived dendritic cells into lung tissue of allergic mice following challenge. Altogether, S. mansoni eggs can protect against the development of AAI, despite strong egg-specific Th2 responses.

Self-similar fragmentation regulated by magnetic fields in a region forming massive stars.

Most molecular clouds are filamentary or elongated. For those forming low-mass stars (<8 solar masses), the competition between self-gravity and turbulent pressure along the dynamically dominant intercloud magnetic field (10 to 100 parsecs) shapes the clouds to be elongated either perpendicularly or parallel to the fields. A recent study also suggested that on the scales of 0.1 to 0.01 parsecs, such fields are dynamically important within cloud cores forming massive stars (>8 solar masses). But whether the core field morphologies are inherited from the intercloud medium or governed by cloud turbulence is unknown, as is the effect of magnetic fields on cloud fragmentation at scales of 10 to 0.1 parsecs. Here we report magnetic-field maps inferred from polarimetric observations of NGC 6334, a region forming massive stars, on the 100 to 0.01 parsec scale. NGC 6334 hosts young star-forming sites where fields are not severely affected by stellar feedback, and their directions do not change much over the entire scale range. This means that the fields are dynamically important. The ordered fields lead to a self-similar gas fragmentation: at all scales, there exist elongated gas structures nearly perpendicular to the fields. Many gas elongations have density peaks near the ends, which symmetrically pinch the fields. The field strength is proportional to the 0.4th power of the density, which is an indication of anisotropic gas contractions along the field. We conclude that magnetic fields have a crucial role in the fragmentation of NGC 6334.

The exact wavefunction factorization of a vibronic coupling system.

We investigate the exact wavefunction as a single product of electronic and nuclear wavefunction for a model conical intersection system. Exact factorized spiky potentials and nodeless nuclear wavefunctions are found. The exact factorized potential preserves the symmetry breaking effect when the coupling mode is present. Additionally nodeless wavefunctions are found to be closely related to the adiabatic nuclear eigenfunctions. This phenomenon holds even for the regime where the non-adiabatic coupling is relevant, and sheds light on the relation between the exact wavefunction factorization and the adiabatic approximation.

Multi-layer Potfit: an accurate potential representation for efficient high-dimensional quantum dynamics.

The multi-layer multi-configuration time-dependent Hartree method (ML-MCTDH) is a highly efficient scheme for studying the dynamics of high-dimensional quantum systems. Its use is greatly facilitated if the Hamiltonian of the system possesses a particular structure through which the multi-dimensional matrix elements can be computed efficiently. In the field of quantum molecular dynamics, the effective interaction between the atoms is often described by potential energy surfaces (PES), and it is necessary to fit such PES into the desired structure. For high-dimensional systems, the current approaches for this fitting process either lead to fits that are too large to be practical, or their accuracy is difficult to predict and control. This article introduces multi-layer Potfit (MLPF), a novel fitting scheme that results in a PES representation in the hierarchical tensor (HT) format. The scheme is based on the hierarchical singular value decomposition, which can yield a near-optimal fit and give strict bounds for the obtained accuracy. Here, a recursive scheme for using the HT-format PES within ML-MCTDH is derived, and theoretical estimates as well as a computational example show that the use of MLPF can reduce the numerical effort for ML-MCTDH by orders of magnitude, compared to the traditionally used POTFIT representation of the PES. Moreover, it is shown that MLPF is especially beneficial for high-accuracy PES representations, and it turns out that MLPF leads to computational savings already for comparatively small systems with just four modes.

Kinetic energy release in fragmentation processes following electron emission: a time-dependent approach.

A time-dependent approach for the kinetic energy release (KER) spectrum is developed for a fragmentation of a diatomic molecule after an electronic decay process, e.g., Auger process. It allows one to simulate the time-resolved spectra and provides more insight into the molecular dynamics than the time-independent approach. Detailed analysis of the time-resolved emitted electron and KER spectra sheds light on the interrelation between wave packet dynamics and spectra.

Interrelation between the distributions of kinetic energy release and emitted electron energy following the decay of electronic states.

In an electronic decay process followed by fragmentation the kinetic energy release and electron spectra can be measured. Classically they are the mirror image of each other, a fact which is often used in practice. Quantum expressions are derived for both spectra and analyzed. It is demonstrated that these spectra carry complementary quantum information and are related to the nuclear dynamics in different participating electronic states. Illustrative examples show that the classical picture of a mirror image can break down and shed light on the underlying physics.

Determination of extractability of pine bark using supercritical CO(2) extraction and different solvents: optimization and prediction.

Bark from Pinus brutia was extracted with supercritical fluid extraction (SFE), using CO(2), at various extraction conditions both at laboratory and at pilot scale. Optimized parameters were 200 bar, 60 degrees C, and 3% ethanol at a solvent/feed ratio of 30. Additionally, the pine bark was sonicated (1 h at 50 degrees C) by different solvents (n-hexane, dichloromethane, ethyl acetate, and ethanol) to investigate the correlation between the different extraction setups and to obtain information on SFE up-scaling possibilities. Analyzed by HPLC, 7.2% of (-)-catechin was extractable at laboratory scale, and 58.4% (800 bar) and 47.8% (200 bar), both with modifiers, at pilot scale. By sonication with ethanol, 46.8% of (-)-catechin and almost 100% of (-)-epicatechin and (-)-catechin gallate were extracted. Ethyl acetate extract revealed high correlations with the laboratory scale SFE (r = 0.98) and also pilot scale SFE runs at 200 (r = 0.99) and 800 bar (r = 0.98) without modifiers.

Rotational excitations in para-H2+para-H2 collisions: full- and reduced-dimensional quantum wave packet studies comparing different potential energy surfaces.

We study the process of rotational excitation in the collisions of para-H(2) with para-H(2) by propagating wave packets with the multiconfiguration time-dependent Hartree (MCTDH) algorithm. Transition probabilities are then calculated by the method of Tannor and Weeks based on time-correlation functions. Calculations were carried out up to a total angular momentum of J=70 to compute integral cross sections up to 1.2 eV in collision energy and thermal rate coefficients from 100 to 3000 K. The process is studied on the full-dimensional potential energy surface of Boothroyd-Martin-Keogh-Peterson (BMKP) as well as on the rigid rotor surface of Diep and Johnson. We test the validity of the rigid rotor approximation by also considering two rigid rotor restrictions of the BMKP potential energy surface (PES). Additionally, we investigate a variant of the BMKP PES suggested by Pogrebnya and Clary [Chem. Phys. Lett. 363, 523 (2002)] with reduced anisotropy. We compare our results with previous theoretical data for the cross sections and with experimental data for the rate coefficients at low temperatures.

Rovibrational energy transfer in ortho-H2+para-H2 collisions.

We present the results of a full-dimensional quantum mechanical study of the rovibrational energy transfer in the collision between ortho-H2 and para-H2 in the energy range of 0.1-1.0 eV. The multiconfiguration time-dependent Hartree algorithm has been used to propagate the wave packets on the global potential energy surface by Boothroyd et al. [J. Chem. Phys. 116, 666 (2002)] and on a modification of this surface where the short range anisotropy is reduced. State-to-state attributes such as probabilities or integral cross sections are obtained using the formalism of Tannor and Weeks [J. Chem. Phys. 98, 3884 (1993)] by Fourier transforming the correlation functions. The effect of initial rotation of the diatoms on the inelastic and de-excitation processes is investigated.

Rotational excitation cross sections of para-H2 + para-H2 collisions. A full-dimensional wave-packet propagation study using an exact form of the kinetic energy.

A full-dimensional quantum dynamical study of the rotational excitation in para-para H2 + H2 collisions using the potential-energy surface of Boothroyd et al. [J. Chem. Phys. 116, 666 (2002)] is reported. The multiconfiguration time-dependent Hartree algorithm is utilized to propagate wave packets and the cross sections for collision energies up to 1.2 eV are determined by a flux analysis through the interaction of the wave packet with a complex absorbing potential. Calculations for a collection of total angular momenta up to J = 70 are performed; the missing channels are obtained with a J-interpolation algorithm.

Supercritical carbon dioxide extraction of marigold at high pressures: comparison of analytical and pilot-scale extraction.

The effects of pressure and co-solvent on the extraction of anti-inflammatory faradiol esters in marigold (Calendula officinalis L.) were investigated by supercritical fluid extraction at laboratory and pilot scales. Pressures higher than 300 bar and modifier (ethanol) concentrations ranging from 0 to 20% (v/v) were used at an extraction temperature of 50 degrees C. With an analytical extractor, exhaustive extraction of the drug and highest concentrations in the extracts were achieved with 0.5% ethanol at the maximum pressure of 689 bar. Increased modifier concentrations improved the extractability at lower pressure, but the higher amount of total extractables led to a lower concentration of faradiol esters in the extracts. The HPLC fingerprints of the extracts, the yields of total extract and the concentration of faradiol esters obtained with analytical and pilot scale extractors under the same conditions were comparable.