A Dose-Response Study on the Relationship between White Meat Intake and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) in Southern Italy: Results from the Nutrihep Study.

(1) Background: Metabolic dysfunction-associated liver disease (MASLD) is one of the most important causes of liver disease worldwide. Meat consumption is a growing trend and white meat has been shown to have beneficial effects on cardiometabolic risk factors. The aim of this study was to investigate the dose-response relationship between white meat intake and MASLD at survey level in a Southern Italy setting. (2) Methods: This cross-sectional study encompassed 1192 subjects (509 males, 42.7%) without missing data from the second wave of the NUTRIHEP cohort (2014-2016). Adjusted dose-response modeling was employed for statistical analysis; (3) Results: There were 587 subjects with MASLD (49.2%), i.e., 278 males (54.6%) and 309 females (45.2%). By increasing the intake, an unfavorable influence of white meat on MASLD was significantly revealed in females, whereas a protective effect of white meat was detectable in males. Male sex was shown to be involved in other associations in this study, such as influencing the preference for specific foods such as poultry and chicken skin. (4) Conclusions: Our data suggest that white meat does not have a clear-cut independent dose-response effect on MASLD, but sex may be a trigger moderator for age and BMI, with an increasing unfavorable effect of white meat in women, and a favorable effect in men.

Ceramide synthesis inhibitors prevent lipid-induced insulin resistance through the DAG-PKCε-insulin receptorT1150 phosphorylation pathway.

Inhibition of the ceramide synthetic pathway with myriocin or an antisense oligonucleotide (ASO) targeting dihydroceramide desaturase (DES1) both improved hepatic insulin sensitivity in rats fed either a saturated or unsaturated fat diet and was associated with reductions in both hepatic ceramide and plasma membrane (PM)-sn-1,2-diacylglycerol (DAG) content. The insulin sensitizing effects of myriocin and Des1 ASO were abrogated by acute treatment with an ASO against DGAT2, which increased hepatic PM-sn-1,2-DAG but not hepatic C16 ceramide content. Increased PM-sn-1,2-DAG content was associated with protein kinase C (PKC)ε activation, increased insulin receptor (INSR)T1150 phosphorylation leading to reduced insulin-stimulated INSRY1152/AktS473 phosphorylation, and impaired insulin-mediated suppression of endogenous glucose production. These results demonstrate that inhibition of de novo ceramide synthesis by either myriocin treatment or DES1 knockdown protects against lipid-induced hepatic insulin resistance through a C16 ceramide-independent mechanism and that they mediate their effects to protect from lipid-induced hepatic insulin resistance via the PM-sn-1,2-DAG-PKCε-INSRT1150 phosphorylation pathway.

Mechanism of Obesity-Related Lipotoxicity and Clinical Perspective.

The link between cellular exposure to fatty acid species and toxicity phenotypes remains poorly understood. However, structural characterization and functional profiling of human plasma free fatty acids (FFAs) analysis has revealed that FFAs are located either in the toxic cluster or in the cluster that is transcriptionally responsive to lipotoxic stress and creates genetic risk factors. Genome-wide short hairpin RNA screen has identified more than 350 genes modulating lipotoxicity. Hypertrophic adipocytes in obese adipose are both unable to expand further to store excess lipids in the diet and are resistant to the antilipolytic action of insulin. In addition to lipolysis, the inability of packaging the excess lipids into lipid droplets causes circulating fatty acids to reach toxic levels in non-adipose tissues. Deleterious effects of accumulated lipid in non-adipose tissues are known as lipotoxicity. Although triglycerides serve a storage function for long-chain non-esterified fatty acid and their products such as ceramide and diacylglycerols (DAGs), overloading of palmitic acid fraction of saturated fatty acids (SFAs) raises ceramide levels. The excess DAG and ceramide load create harmful effects on multiple organs and systems, inducing chronic inflammation in obesity. Thus, lipotoxic inflammation results in ß cells death and pancreatic islets dysfunction. Endoplasmic reticulum stress stimuli induce lipolysis by activating cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) and extracellular signal-regulated kinase (Erk) 1/2 signaling in adipocytes. However, palmitic acid-induced endoplasmic reticulum stress-c-Jun N-terminal kinase (JNK)-autophagy axis in hypertrophic adipocytes is a pro-survival mechanism against endoplasmic reticulum stress and cell death induced by SFAs. Endoplasmic reticulum-localized acyl-coenzyme A (CoA): glycerol-3-phosphate acyltransferase (GPAT) enzymes are mediators of lipotoxicity, and inhibiting these enzymes has therapeutic potential for lipotoxicity. Lipotoxicity increases the number of autophagosomes, which engulf palmitic acid, and thus suppress the autophagic turnover. Fatty acid desaturation promotes palmitate detoxification and storages into triglycerides. As therapeutic targets of glucolipotoxicity, in addition to caloric restriction and exercise, there are four different pharmacological approaches, which consist of metformin, glucagon-like peptide 1 (GLP-1) receptor agonists, peroxisome proliferator-activated receptor-gamma (PPARγ) ligands thiazolidinediones, and chaperones are still used in clinical practice. Furthermore, induction of the brown fat-like phenotype with the mixture of eicosapentanoic acid and docosahexaenoic acid appears as a potential therapeutic application for treatment of lipotoxicity.

Nonalcoholic Fatty Liver Disease and Staging of Hepatic Fibrosis.

Nonalcoholic fatty liver disease (NAFLD) is in parallel with the obesity epidemic, and it is the most common cause of liver diseases. The patients with severe insulin-resistant diabetes having high body mass index (BMI), high-grade adipose tissue insulin resistance, and high hepatocellular triacylglycerols (triglycerides; TAG) content develop hepatic fibrosis within a 5-year follow-up. Insulin resistance with the deficiency of insulin receptor substrate-2 (IRS-2)-associated phosphatidylinositol 3-kinase (PI3K) activity causes an increase in intracellular fatty acid-derived metabolites such as diacylglycerol (DAG), fatty acyl CoA, or ceramides. Lipotoxicity-related mechanism of NAFLD could be explained still best by the "double-hit" hypothesis. Insulin resistance is the major mechanism in the development and progression of NAFLD/nonalcoholic steatohepatitis (NASH). Metabolic oxidative stress, autophagy, and inflammation induce NASH progression. In the "first hit" the hepatic concentrations of diacylglycerol increase with an increase in saturated liver fat content in human NAFLD. Activities of mitochondrial respiratory chain complexes are decreased in the liver tissue of patients with NASH. Hepatocyte lipoapoptosis is a critical feature of NASH. In the "second hit," reduced glutathione levels due to oxidative stress lead to the overactivation of c-Jun N-terminal kinase (JNK)/c-Jun signaling that induces cell death in the steatotic liver. Accumulation of toxic levels of reactive oxygen species (ROS) is caused at least by two ineffectual cyclical pathways. First is the endoplasmic reticulum (ER) oxidoreductin (Ero1)-protein disulfide isomerase oxidation cycle through the downstream of the inner membrane mitochondrial oxidative metabolism and the second is the Kelch like-ECH-associated protein 1 (Keap1)-nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathways. In clinical practice, on ultrasonographic examination, the elevation of transaminases, γ-glutamyltransferase, and the aspartate transaminase to platelet ratio index indicates NAFLD. Fibrosis-4 index, NAFLD fibrosis score, and cytokeratin18 are used for grading steatosis, staging fibrosis, and discriminating the NASH from simple steatosis, respectively. In addition to ultrasonography, "controlled attenuation parameter," "magnetic resonance imaging proton-density fat fraction," "ultrasound-based elastography," "magnetic resonance elastography," "acoustic radiation force impulse elastography imaging," "two-dimensional shear-wave elastography with supersonic imagine," and "vibration-controlled transient elastography" are recommended as combined tests with serum markers in the clinical evaluation of NAFLD. However, to confirm the diagnosis of NAFLD, a liver biopsy is the gold standard. Insulin resistance-associated hyperinsulinemia directly accelerates fibrogenesis during NAFLD development. Although hepatocyte lipoapoptosis is a key driving force of fibrosis progression, hepatic stellate cells and extracellular matrix cells are major fibrogenic effectors. Thereby, these are pharmacological targets of therapies in developing hepatic fibrosis. Nonpharmacological management of NAFLD mainly consists of two alternatives: lifestyle modification and metabolic surgery. Many pharmacological agents that are thought to be effective in the treatment of NAFLD have been tried, but due to lack of ability to attenuate NAFLD, or adverse effects during the phase trials, the vast majority could not be licensed.

Immunomodulatory Effects and Regulatory Mechanisms of (R)-6-HITC, an Isothiocyanate from Wasabi (Eutrema japonicum), in an Ex Vivo Mouse Model of LPS-Induced Inflammation.

The present study aimed to investigate the effects of (R)-(-)-1-isothiocyanato-6-(methylsulfinyl)-hexane [(R)-6-HITC], the major isothiocyanate present in wasabi, in an ex vivo model of inflammation using lipopolysaccharide-stimulated murine peritoneal macrophages. (R)-6-HITC improved the immune response and mitigated oxidative stress, which involved suppression of reactive oxygen species, nitric oxide, and pro-inflammatory cytokines (IL-1ß, IL-6, IL-17, IL-18, and TNF-α) production and downregulation of pro-inflammatory enzymes such as inducible nitric oxide synthase, COX-2, and mPGES-1. In addition, (R)-6-HITC was able to activate the Nrf2/HO-1 axis while simultaneously inhibiting key signaling pathways, including JAK2/STAT3, mitogen-activated protein kinases, and canonical and noncanonical inflammasome pathways, orchestrating its potent immunomodulatory effects. Collectively, these findings demonstrate the potential of (R)-6-HITC as a promising nutraceutical for the management of immuno-inflammatory diseases and justify the need for further in vivo validation studies.

Fat Mass- and Obesity-Associated Protein (FTO) Promotes the Proliferation of Goat Skeletal Muscle Satellite Cells by Stabilizing DAG1 mRNA in an IGF2BP1-Related m6A Manner.

Skeletal muscle development is spotlighted in mammals since it closely relates to animal health and economic benefits to the breeding industry. Researchers have successfully unveiled many regulatory factors and mechanisms involving myogenesis. However, the effect of N6-methyladenosine (m6A) modification, especially demethylase and its regulated genes, on muscle development remains to be further explored. Here, we found that the typical demethylase FTO (fat mass- and obesity-associated protein) was highly enriched in goats' longissimus dorsi (LD) muscles. In addition, the level of m6A modification on transcripts was negatively regulated by FTO during the proliferation of goat skeletal muscle satellite cells (MuSCs). Moreover, a deficiency of FTO in MuSCs significantly retarded their proliferation and promoted the expression of dystrophin-associated protein 1 (DAG1). m6A modifications of DAG1 mRNA were efficiently altered by FTO. Intriguingly, the results of DAG1 levels and its m6A enrichment from FB23-2 (FTO demethylase inhibitor)-treated cells were consistent with those of the FTO knockdown, indicating that the regulation of FTO on DAG1 depended on m6A modification. Further experiments showed that interfering FTO improved m6A modification at site DAG1-122, recognized by Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) and consequently stabilized DAG1 transcripts. Our study suggests that FTO promotes the proliferation of MuSCs by regulating the expression of DAG1 through m6A modification. This will extend our knowledge of the m6A-related mechanism of skeletal muscle development in animals.

Temporal dissociation of COX-2-dependent arachidonic acid and 2-arachidonoylglycerol metabolism in RAW264.7 macrophages.

Cyclooxygenase-2 converts arachidonic acid to prostaglandins (PGs) and the endocannabinoid, 2-arachidonoylglycerol (2-AG), to PG glyceryl esters (PG-Gs). The physiological function of PG biosynthesis has been extensively studied, but the importance of the more recently discovered PG-G synthetic pathway remains incompletely defined. This disparity is due in part to a lack of knowledge of the physiological conditions under which PG-G biosynthesis occurs. We have discovered that RAW264.7 macrophages stimulated with Kdo2-lipid A (KLA) produce primarily PGs within the first 12 h followed by robust PG-G synthesis between 12 h and 24 h. We suggest that the amount of PG-Gs quantified is less than actually synthesized, because PG-Gs are subject to a significant level of hydrolysis during the time course of synthesis. Inhibition of cytosolic phospholipase A2 by giripladib does not accelerate PG-G synthesis, suggesting the differential time course of PG and PG-G synthesis is not due to the competition between arachidonic acid and 2-AG. The late-phase PG-G formation is accompanied by an increase in the level of 2-AG and a concomitant decrease in 18:0-20:4 diacylglycerol (DAG). Inhibition of DAG lipases by KT-172 decreases the levels of 2-AG and PG-Gs, indicating that the DAG-lipase pathway is involved in delayed 2-AG metabolism/PG-G synthesis. These results demonstrate that physiologically significant levels of PG-Gs are produced by activated RAW264.7 macrophages well after the production of PGs plateaus.

Isolation and Molecular Characterization of the LTA precursor molecule Glc2-DAG, a potential target for antibiotics.

Bacterial infections present a major global health threat, often displaying resistance to various antibiotics. Lipoteichoic acid (LTA) is a vital component of bacterial cell envelopes of Gram-positive bacteria, crucial for cell integrity, cell division, and host inflammation. Due to its essential role for bacteria, LTA and its biosynthesis are also attractive drug targets, however, there is only scant molecular knowledge on LTA and its precursor molecules in membranes. Here, we report the isolation and molecular characterization of diglucosyldiacylglycerol (Glc2-DAG), the glycolipid precursor molecule that anchors LTA in the bacterial plasma-membrane. Using a tailored growth medium and purification protocols, we isolated 13C-isotope labelled Glc2-DAG from bacteria, which can then be used for high-resolution NMR studies. Using solution-state and solid-state NMR, we show an in-depth molecular characterization of Glc2-DAG, including in native-like membranes. Our approach may help to identify antibiotics that directly target LTA precursor molecules, and it offers a tool for future investigations into the role of Glc2-DAG in bacterial physiology.

RadDeploy: A framework for integrating in-house developed software and artificial intelligence models seamlessly into radiotherapy workflows.

The use of and research in automation and artificial intelligence (AI) in radiotherapy is moving with incredible pace. Many innovations do, however, not make it into the clinic. One technical reason for this may be the lack of a platform to deploy such software into clinical practice. We suggest RadDeploy as a framework for integrating containerized software in clinical workflows outside of treatment planning systems. RadDeploy supports multiple DICOM as input for model containers and can run model containers asynchronously across GPUs and computers. This technical note summarizes the inner workings of RadDeploy and demonstrates three use-cases with varying complexity.

Ectopic Expression of C-Type Lectin Mincle Renders Mice Susceptible to Staphylococcal Pneumonia.

Staphylococcus aureus is a prevalent pathogen in pneumonia and harbors glycolipids, which may serve as molecular patterns in Mincle (macrophage-inducible C-type lectin)-dependent pathogen recognition. We examined the role of Mincle in lung defense against S aureus in wild-type (WT), Mincle knockout (KO), and Mincle transgenic (tg) mice. Two glycolipids, glucosyl-diacylglycerol (Glc-DAG) and diglucosyl-diacylglycerol (Glc2-DAG), were purified, of which only Glc-DAG triggered Mincle reporter cell activation and professional phagocyte responses. Proteomic profiling revealed that Glc2-DAG blocked Glc-DAG-induced cytokine responses, thereby acting as inhibitor of Glc-DAG/Mincle signaling. WT mice responded to S aureus with a similar lung pathology as Mincle KO mice, most likely due to Glc2-DAG-dependent inhibition of Glc-DAG/Mincle signaling. In contrast, ectopic Mincle expression caused severe lung pathology in S aureus-infected mice, characterized by bacterial outgrowth and fatal pneumonia. Collectively, Glc2-DAG inhibits Glc-DAG/Mincle-dependent responses in WT mice, whereas sustained Mincle expression overrides Glc2-DAG-mediated inhibitory effects, conferring increased host susceptibility to S aureus.

Diacylglycerol kinase is a keystone regulator of signaling relevant to the pathophysiology of asthma.

Signal transduction by G protein-coupled receptors (GPCRs), receptor tyrosine kinases (RTKs) and immunoreceptors converge at the activation of phospholipase C (PLC) for the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). This is a point for second-messenger bifurcation where DAG via protein kinase C (PKC) and IP3 via calcium activate distinct protein targets and regulate cellular functions. IP3 signaling is regulated by multiple calcium influx and efflux proteins involved in calcium homeostasis. A family of lipid kinases belonging to DAG kinases (DGKs) converts DAG to phosphatidic acid (PA), negatively regulating DAG signaling and pathophysiological functions. PA, through a series of biochemical reactions, is recycled to produce new molecules of PIP2. Therefore, DGKs act as a central switch in terminating DAG signaling and resynthesis of membrane phospholipids precursor. Interestingly, calcium and PKC regulate the activation of α and ζ isoforms of DGK that are predominantly expressed in airway and immune cells. Thus, DGK forms a feedback and feedforward control point and plays a crucial role in fine-tuning phospholipid stoichiometry, signaling, and functions. In this review, we discuss the previously underappreciated complex and intriguing DAG/DGK-driven mechanisms in regulating cellular functions associated with asthma, such as contraction and proliferation of airway smooth muscle (ASM) cells and inflammatory activation of immune cells. We highlight the benefits of manipulating DGK activity in mitigating salient features of asthma pathophysiology and shed light on DGK as a molecule of interest for heterogeneous diseases such as asthma.

Discovery of Potent DAG-Lactone Derivatives as HIV Latency Reversing Agents.

Toward human immunodeficiency virus type-1 (HIV-1) cure, cells latently infected with HIV-1 must be eliminated from people living with HIV-1. We previously developed a protein kinase C (PKC) activator, diacylglycerol (DAG)-lactone derivative 3, with high HIV-1 latency-reversing activity, based on YSE028 (2) as a lead compound and found that the activity was correlated with binding affinity for PKC and stability against esterase-mediated hydrolysis. Here, we synthesized new DAG-lactone derivatives not only containing a tertiary ester group or an isoxazole surrogate but also several symmetric alkylidene moieties to improve HIV-1 latency reversing activity. Compound 9a, with a dimethyl group at the α-position of the ester group, exerted twice higher HIV-1 latency reversing activity than compound 3, and compound 26, with the isoxazole moiety, was significantly active. In addition, DAG-lactone derivatives with moderate hydrophobicity and potent biostability showed high biological activity.

Metallo-Glycodendrimeric Materials against Enterotoxigenic Escherichia coli.

Conjugation of carbohydrates to nanomaterials has been extensively studied and recognized as an alternative in the biomedical field. Dendrimers synthesized with mannose at the end group and with entrapped zero-valent copper/silver could be a potential candidate against bacterial proliferation. This study is aimed at investigating the bactericidal activity of metal-glycodendrimers. The Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction was used to synthesize a new mannosylated dendrimer containing 12 mannopyranoside residues in the periphery. The enterotoxigenic Escherichia coli fimbriae 4 (ETEC:F4) viability, measured at 600 nm, showed the half-inhibitory concentration (IC50) of metal-free glycodendrimers (D), copper-loaded glycodendrimers (D:Cu) and silver-loaded glycodendrimers (D:Ag) closed to 4.5 × 101, 3.5 × 101 and to 1.0 × 10-2 µg/mL, respectively, and minimum inhibitory concentration (MIC) of D, D:Cu and D:Ag of 2.0, 1.5 and 1.0 × 10-4 µg/mL, respectively. The release of bacteria contents onto broth and the inhibition of ETEC:F4 biofilm formation increased with the number of metallo-glycodendrimer materials, with a special interest in silver-containing nanomaterial, which had the highest activity, suggesting that glycodendrimer-based materials interfered with bacteria-bacteria or bacteria-polystyrene interactions, with bacteria metabolism and can disrupt bacteria cell walls. Our findings identify metal-mannose-dendrimers as potent bactericidal agents and emphasize the effect of entrapped zero-valent metal against ETEC:F4.

A computable biomedical knowledge system: Toward rapidly building candidate-directed acyclic graphs.

AIM: It is essential for health researchers to have a systematic understanding of third-party variables that influence both the exposure and outcome under investigation, as shown by a directed acyclic graph (DAG). The traditional construction of DAGs through literature review and expert knowledge often needs to be more systematic and consistent, leading to potential biases. We try to introduce an automatic approach to building network linking variables of interest. METHODS: Large-scale text mining from medical literature was utilized to construct a conceptual network based on the Semantic MEDLINE Database (SemMedDB). SemMedDB is a PubMed-scale repository of the "concept-relation-concept" triple format. Relations between concepts are categorized as Excitatory, Inhibitory, or General. RESULTS: To facilitate the use of large-scale triple sets in SemMedDB, we have developed a computable biomedical knowledge (CBK) system (https://cbk.bjmu.edu.cn/), a website that enables direct retrieval of related publications and their corresponding triples without the necessity of writing SQL statements. Three case studies were elaborated to demonstrate the applications of the CBK system. CONCLUSIONS: The CBK system is openly available and user-friendly for rapidly capturing a set of influencing factors for a phenotype and building candidate DAGs between exposure-outcome variables. It could be a valuable tool to reduce the exploration time in considering relationships between variables, and constructing a DAG. A reliable and standardized DAG could significantly improve the design and interpretation of observational health research.

Recoverability and estimation of causal effects under typical multivariable missingness mechanisms.

In the context of missing data, the identifiability or "recoverability" of the average causal effect (ACE) depends not only on the usual causal assumptions but also on missingness assumptions that can be depicted by adding variable-specific missingness indicators to causal diagrams, creating missingness directed acyclic graphs (m-DAGs). Previous research described canonical m-DAGs, representing typical multivariable missingness mechanisms in epidemiological studies, and examined mathematically the recoverability of the ACE in each case. However, this work assumed no effect modification and did not investigate methods for estimation across such scenarios. Here, we extend this research by determining the recoverability of the ACE in settings with effect modification and conducting a simulation study to evaluate the performance of widely used missing data methods when estimating the ACE using correctly specified g-computation. Methods assessed were complete case analysis (CCA) and various implementations of multiple imputation (MI) with varying degrees of compatibility with the outcome model used in g-computation. Simulations were based on an example from the Victorian Adolescent Health Cohort Study (VAHCS), where interest was in estimating the ACE of adolescent cannabis use on mental health in young adulthood. We found that the ACE is recoverable when no incomplete variable (exposure, outcome, or confounder) causes its own missingness, and nonrecoverable otherwise, in simplified versions of 10 canonical m-DAGs that excluded unmeasured common causes of missingness indicators. Despite this nonrecoverability, simulations showed that MI approaches that are compatible with the outcome model in g-computation may enable approximately unbiased estimation across all canonical m-DAGs considered, except when the outcome causes its own missingness or causes the missingness of a variable that causes its own missingness. In the latter settings, researchers may need to consider sensitivity analysis methods incorporating external information (e.g., delta-adjustment methods). The VAHCS case study illustrates the practical implications of these findings.

County Mammogram Uptake can be Predicted from Social Determinants of Health, but Patterns Do Not Hold for Individual Patients.

Purpose: The objective of this study is to describe patterns in barriers to breast cancer screening uptake with the end goal of improving screening adherence and decreasing the burden of mortality due to breast cancer. This study looks at social determinants of health and their association to screening and mortality. It also investigates the extent that models trained on county data are generalizable to individuals. Methods: County level screening uptake and age adjusted mortality due to breast cancer are combined with the Centers for Disease Controls Social Vulnerability Index (SVI) to train a model predicting screening uptake rates. Patterns learned are then applied to de-identified electronic medical records from individual patients to make predictions on mammogram screening follow through. Results: Accurate predictions can be made about a county's breast cancer screening uptake with the SVI. However, the association between increased screening, and decreased age adjusted mortality, doesn't hold in areas with a high proportion of minority residents. It is also shown that patterns learned from county SVI data have little discriminative power at the patient level. Conclusion: This study demonstrates that social determinants in the SVI can explain much of the variance in county breast cancer screening rates. However, these same patterns fail to discriminate which patients will have timely follow through of a mammogram screening test. This study also concludes that the core association between increased screening and decreased age adjusted mortality does not hold in high proportion minority areas. Objective: The objective of this study is to describe patterns in social determinants of health and their association with female breast cancer screening uptake, age adjusted breast cancer mortality rate and the extent that models trained on county data are generalizable to individuals.

Exploring a Potential Interaction Between the Effect of Specific Maternal Smoking Patterns and Comorbid Antenatal Depression in Causing Postpartum Depression.

Purpose: To explore a potential interaction between the effect of specific maternal smoking patterns and the presence of antenatal depression, as independent exposures, in causing postpartum depression (PPD). Methods: This case-control study of participants with singleton term births (N = 51220) was based on data from the 2017-2018 Pregnancy Risk Assessment Monitoring System. Multivariable log-binomial regression models examined the main effects of smoking patterns and self-reported symptoms of antenatal depression on the risk of PPD on the adjusted risk ratio (aRR) scale and tested a two-way interaction adjusting for covariates selected in a directed acyclic graph (DAG). The interaction effects were measured on the additive scale using relative excess risk due to interaction (RERI), the attributable proportion of interaction (AP), and the synergy index (SI). Causal effects were defined in a counterfactual framework. The E-value quantified the potential impact of unobserved/unknown covariates, conditional on observed covariates. Results: Among 6841 women in the sample who self-reported PPD, 35.7% also reported symptoms of antenatal depression. Out of 3921 (7.7%) women who reported smoking during pregnancy, 32.6% smoked at high intensity (≥10 cigarettes/day) in all three trimesters and 36.6% had symptoms of antenatal depression. The main effect of PPD was the strongest for women who smoked at high intensity throughout pregnancy (aRR 1.65; 95% CI: 1.63, 1.68). A synergistic interaction was detected, and the effect of all maternal smoking patterns was augmented, particularly in late pregnancy for Increasers and Reducers. Conclusion: Strong associations and interaction effects between maternal smoking patterns and co-occurring antenatal depression support smoking prevention and cessation interventions during pregnancy to lower the likelihood of PPD.

Inferring a directed acyclic graph of phenotypes from GWAS summary statistics.

Estimating phenotype networks is a growing field in computational biology. It deepens the understanding of disease etiology and is useful in many applications. In this study, we present a method that constructs a phenotype network by assuming a Gaussian linear structure model embedding a directed acyclic graph (DAG). We utilize genetic variants as instrumental variables and show how our method only requires access to summary statistics from a genome-wide association study (GWAS) and a reference panel of genotype data. Besides estimation, a distinct feature of the method is its summary statistics-based likelihood ratio test on directed edges. We applied our method to estimate a causal network of 29 cardiovascular-related proteins and linked the estimated network to Alzheimer's disease (AD). A simulation study was conducted to demonstrate the effectiveness of this method. An R package sumdag implementing the proposed method, all relevant code, and a Shiny application are available.

A longitudinal causal graph analysis investigating modifiable risk factors and obesity in a European cohort of children and adolescents.

Childhood obesity is a complex disorder that appears to be influenced by an interacting system of many factors. Taking this complexity into account, we aim to investigate the causal structure underlying childhood obesity. Our focus is on identifying potential early, direct or indirect, causes of obesity which may be promising targets for prevention strategies. Using a causal discovery algorithm, we estimate a cohort causal graph (CCG) over the life course from childhood to adolescence. We adapt a popular method, the so-called PC-algorithm, to deal with missing values by multiple imputation, with mixed discrete and continuous variables, and that takes background knowledge such as the time-structure of cohort data into account. The algorithm is then applied to learn the causal structure among 51 variables including obesity, early life factors, diet, lifestyle, insulin resistance, puberty stage and cultural background of 5112 children from the European IDEFICS/I.Family cohort across three waves (2007-2014). The robustness of the learned causal structure is addressed in a series of alternative and sensitivity analyses; in particular, we use bootstrap resamples to assess the stability of aspects of the learned CCG. Our results suggest some but only indirect possible causal paths from early modifiable risk factors, such as audio-visual media consumption and physical activity, to obesity (measured by age- and sex-adjusted BMI z-scores) 6 years later.

The Role of Neutral Sphingomyelinase-2 (NSM2) in the Control of Neutral Lipid Storage in T Cells.

The accumulation of lipid droplets (LDs) and ceramides (Cer) is linked to non-alcoholic fatty liver disease (NAFLD), regularly co-existing with type 2 diabetes and decreased immune function. Chronic inflammation and increased disease severity in viral infections are the hallmarks of the obesity-related immunopathology. The upregulation of neutral sphingomyelinase-2 (NSM2) has shown to be associated with the pathology of obesity in tissues. Nevertheless, the role of sphingolipids and specifically of NSM2 in the regulation of immune cell response to a fatty acid (FA) rich environment is poorly studied. Here, we identified the presence of the LD marker protein perilipin 3 (PLIN3) in the intracellular nano-environment of NSM2 using the ascorbate peroxidase APEX2-catalyzed proximity-dependent biotin labeling method. In line with this, super-resolution structured illumination microscopy (SIM) shows NSM2 and PLIN3 co-localization in LD organelles in the presence of increased extracellular concentrations of oleic acid (OA). Furthermore, the association of enzymatically active NSM2 with isolated LDs correlates with increased Cer levels in these lipid storage organelles. NSM2 enzymatic activity is not required for NSM2 association with LDs, but negatively affects the LD numbers and cellular accumulation of long-chain unsaturated triacylglycerol (TAG) species. Concurrently, NSM2 expression promotes mitochondrial respiration and fatty acid oxidation (FAO) in response to increased OA levels, thereby shifting cells to a high energetic state. Importantly, endogenous NSM2 activity is crucial for primary human CD4+ T cell survival and proliferation in a FA rich environment. To conclude, our study shows a novel NSM2 intracellular localization to LDs and the role of enzymatically active NSM2 in metabolic response to enhanced FA concentrations in T cells.