Membrane-bound O-acyltransferase 7 (MBOAT7) shapes lysosomal lipid homeostasis and function to control alcohol-associated liver injury.

Recent genome-wide association studies (GWAS) have identified a link between single-nucleotide polymorphisms (SNPs) near the MBOAT7 gene and advanced liver diseases. Specifically, the common MBOAT7 variant (rs641738) associated with reduced MBOAT7 expression is implicated in non-alcoholic fatty liver disease (NAFLD), alcohol-associated liver disease (ALD), and liver fibrosis. However, the precise mechanism underlying MBOAT7-driven liver disease progression remains elusive. Previously, we identified MBOAT7-driven acylation of lysophosphatidylinositol lipids as key mechanism suppressing the progression of NAFLD (Gwag et al., 2019). Here, we show that MBOAT7 loss of function promotes ALD via reorganization of lysosomal lipid homeostasis. Circulating levels of MBOAT7 metabolic products are significantly reduced in heavy drinkers compared to healthy controls. Hepatocyte- (Mboat7-HSKO), but not myeloid-specific (Mboat7-MSKO), deletion of Mboat7 exacerbates ethanol-induced liver injury. Lipidomic profiling reveals a reorganization of the hepatic lipidome in Mboat7-HSKO mice, characterized by increased endosomal/lysosomal lipids. Ethanol-exposed Mboat7-HSKO mice exhibit dysregulated autophagic flux and lysosomal biogenesis, associated with impaired transcription factor EB-mediated lysosomal biogenesis and autophagosome accumulation. This study provides mechanistic insights into how MBOAT7 influences ALD progression through dysregulation of lysosomal biogenesis and autophagic flux, highlighting hepatocyte-specific MBOAT7 loss as a key driver of ethanol-induced liver injury.

Dietary lipid is largely deposited in skin and rapidly affects insulating properties.

Skin has been shown to be a regulatory hub for energy expenditure and metabolism: mutations of skin lipid metabolism enzymes can change the rate of thermogenesis and susceptibility to diet-induced obesity. However, little is known about the physiological basis for this function. Here we show that the thermal properties of skin are highly reactive to diet: within three days, a high fat diet reduces heat transfer through skin. In contrast, a dietary manipulation that prevents obesity accelerates energy loss through skins. We found that skin was the largest target in a mouse body for dietary fat delivery, and that fat was assimilated both by epidermis and by dermal white adipose tissue. Dietary triglyceride acyl groups persist in skin for weeks after feeding. Using multi-modal lipid profiling, we have implicated both keratinocytes and sebocytes in the altered lipids which correlate with thermal function. In response to high fat feeding, wax diesters and ceramides accumulate, and triglycerides become more saturated. In contrast, in response to the dramatic loss of adipose tissue that accompanies restriction of the branched chain amino acid isoleucine, skin becomes highly heat-permeable: skins shows limited uptake of dietary lipids and editing of wax esters, and acquires a signature of depleted signaling lipids, which include the acyl carnitines and lipid ethers. We propose that skin should be routinely included in physiological studies of lipid metabolism, given the size of the skin lipid reservoir and its adaptable functionality.

Large language models as tax attorneys: a case study in legal capabilities emergence.

Better understanding of Large Language Models' (LLMs) legal analysis abilities can contribute to improving the efficiency of legal services, governing artificial intelligence and leveraging LLMs to identify inconsistencies in law. This paper explores LLM capabilities in applying tax law. We choose this area of law because it has a structure that allows us to set up automated validation pipelines across thousands of examples, requires logical reasoning and maths skills, and enables us to test LLM capabilities in a manner relevant to real-world economic lives of citizens and companies. Our experiments demonstrate emerging legal understanding capabilities, with improved performance in each subsequent OpenAI model release. We experiment with retrieving and using the relevant legal authority to assess the impact of providing additional legal context to LLMs. Few-shot prompting, presenting examples of question-answer pairs, is also found to significantly enhance the performance of the most advanced model, GPT-4. The findings indicate that LLMs, particularly when combined with prompting enhancements and the correct legal texts, can perform at high levels of accuracy but not yet at expert tax lawyer levels. As LLMs continue to advance, their ability to reason about law autonomously could have significant implications for the legal profession and AI governance. This article is part of the theme issue 'A complexity science approach to law and governance'.

ACAD10 and ACAD11 enable mammalian 4-hydroxy acid lipid catabolism.

Fatty acid ß-oxidation (FAO) is a central catabolic pathway with broad implications for organismal health. However, various fatty acids are largely incompatible with standard FAO machinery until they are modified by other enzymes. Included among these are the 4-hydroxy acids (4-HAs)-fatty acids hydroxylated at the 4 (γ) position-which can be provided from dietary intake, lipid peroxidation, and certain drugs of abuse. Here, we reveal that two atypical and poorly characterized acyl-CoA dehydrogenases (ACADs), ACAD10 and ACAD11, drive 4-HA catabolism in mice. Unlike other ACADs, ACAD10 and ACAD11 feature kinase domains N-terminal to their ACAD domains that phosphorylate the 4-OH position as a requisite step in the conversion of 4-hydroxyacyl-CoAs into 2-enoyl-CoAs-conventional FAO intermediates. Our ACAD11 cryo-EM structure and molecular modeling reveal a unique binding pocket capable of accommodating this phosphorylated intermediate. We further show that ACAD10 is mitochondrial and necessary for catabolizing shorter-chain 4-HAs, whereas ACAD11 is peroxisomal and enables longer-chain 4-HA catabolism. Mice lacking ACAD11 accumulate 4-HAs in their plasma while comparable 3- and 5-hydroxy acids remain unchanged. Collectively, this work defines ACAD10 and ACAD11 as the primary gatekeepers of mammalian 4-HA catabolism and sets the stage for broader investigations into the ramifications of aberrant 4-HA metabolism in human health and disease.

Membrane Bound O-Acyltransferase 7 (MBOAT7) Shapes Lysosomal Lipid Homeostasis and Function to Control Alcohol-Associated Liver Injury.

Several recent genome-wide association studies (GWAS) have identified single nucleotide polymorphism (SNPs) near the gene encoding membrane-bound O -acyltransferase 7 ( MBOAT7 ) that is associated with advanced liver diseases. In fact, a common MBOAT7 variant (rs641738), which is associated with reduced MBOAT7 expression, confers increased susceptibility to non-alcoholic fatty liver disease (NAFLD), alcohol-associated liver disease (ALD), and liver fibrosis in those chronically infected with hepatitis viruses B and C. The MBOAT7 gene encodes a lysophosphatidylinositol (LPI) acyltransferase enzyme that produces the most abundant form of phosphatidylinositol 38:4 (PI 18:0/20:4). Although these recent genetic studies clearly implicate MBOAT7 function in liver disease progression, the mechanism(s) by which MBOAT7-driven LPI acylation regulates liver disease is currently unknown. Previously we showed that antisense oligonucleotide (ASO)-mediated knockdown of Mboat7 promoted non-alcoholic fatty liver disease (NAFLD) in mice (Helsley et al., 2019). Here, we provide mechanistic insights into how MBOAT7 loss of function promotes alcohol-associated liver disease (ALD). In agreement with GWAS studies, we find that circulating levels of metabolic product of MBOAT7 (PI 38:4) are significantly reduced in heavy drinkers compared to age-matched healthy controls. Hepatocyte specific genetic deletion ( Mboat7 HSKO ), but not myeloid-specific deletion ( Mboat7 MSKO ), of Mboat7 in mice results in enhanced ethanol-induced hepatic steatosis and high concentrations of plasma alanine aminotransferase (ALT). Given MBOAT7 is a lipid metabolic enzyme, we performed comprehensive lipidomic profiling of the liver and identified a striking reorganization of the hepatic lipidome upon ethanol feeding in Mboat7 HSKO mice. Specifically, we observed large increases in the levels of endosomal/lysosomal lipids including bis(monoacylglycero)phosphates (BMP) and phosphatidylglycerols (PGs) in ethanol-exposed Mboat7 HSKO mice. In parallel, ethanol-fed Mboat7 HSKO mice exhibited marked dysregulation of autophagic flux and lysosomal biogenesis when exposed to ethanol. This was associated with impaired transcription factor EB (TFEB)-mediated lysosomal biogenesis and accumulation of autophagosomes. Collectively, this works provides new molecular insights into how genetic variation in MBOAT7 impacts ALD progression in humans and mice. This work is the first to causally link MBOAT7 loss of function in hepatocytes, but not myeloid cells, to ethanol-induced liver injury via dysregulation of lysosomal biogenesis and autophagic flux.

Dietary restriction of isoleucine increases healthspan and lifespan of genetically heterogeneous mice.

Low-protein diets promote health and longevity in diverse species. Restriction of the branched-chain amino acids (BCAAs) leucine, isoleucine, and valine recapitulates many of these benefits in young C57BL/6J mice. Restriction of dietary isoleucine (IleR) is sufficient to promote metabolic health and is required for many benefits of a low-protein diet in C57BL/6J males. Here, we test the hypothesis that IleR will promote healthy aging in genetically heterogeneous adult UM-HET3 mice. We find that IleR improves metabolic health in young and old HET3 mice, promoting leanness and glycemic control in both sexes, and reprograms hepatic metabolism in a sex-specific manner. IleR reduces frailty and extends the lifespan of male and female mice, but to a greater degree in males. Our results demonstrate that IleR increases healthspan and longevity in genetically diverse mice and suggests that IleR, or pharmaceuticals that mimic this effect, may have potential as a geroprotective intervention.

Modulation of hepatic transcription factor EB activity during cold exposure uncovers direct regulation of bis(monoacylglycero)phosphate lipids by Pla2g15.

Cold exposure is an environmental stress that elicits a rapid metabolic shift in endotherms and is required for survival. The liver provides metabolic flexibility through its ability to rewire lipid metabolism to respond to an increased demand in energy for thermogenesis. We leveraged cold exposure to identify novel lipids contributing to energy homeostasis and found that lysosomal bis(monoacylglycero)phosphate (BMP) lipids were significantly increased in the liver during acute cold exposure. BMP lipid changes occurred independently of lysosomal abundance but were dependent on the lysosomal transcriptional regulator transcription factor EB (TFEB). Knockdown of TFEB in hepatocytes decreased BMP lipid levels. Through molecular biology and biochemical assays, we found that TFEB regulates lipid catabolism during cold exposure and that TFEB knockdown mice were cold intolerant. To identify how TFEB regulates BMP lipid levels, we used a combinatorial approach to identify TFEB target Pla2g15 , a lysosomal phospholipase, as capable of degrading BMP lipids in in vitro liposome assays. Knockdown of Pla2g15 in hepatocytes led to a decrease in BMP lipid species. Together, our studies uncover a required role of TFEB in mediating lipid liver remodeling during cold exposure and identified Pla2g15 as an enzyme that regulates BMP lipid catabolism.

"Humanizing" mouse environments: Humidity, diurnal cycles and thermoneutrality.

Thermoneutral housing has been shown to promote more accurate and robust development of several pathologies in mice. Raising animal housing temperatures a few degrees may create a relatively straightforward opportunity to improve translatability of mouse models. In this commentary, we discuss the changes of physiology induced in mice housed at thermoneutrality, and review techniques for measuring systemic thermogenesis, specifically those affecting storage and mobilization of lipids in adipose depots. Environmental cues are a component of the information integrated by the brain to calculate food consumption and calorie deposition. We show that relative humidity is one of those cues, inducing a rapid sensory response that is converted to a more chronic susceptibility to obesity. Given high inter-institutional variability in the regulation of relative humidity, study reproducibility may be improved by consideration of this factor. We evaluate a "humanized" environmental cycling protocol, where mice sleep in warm temperature housing, and are cool during the wake cycle. We show that this protocol suppresses adaptation to cool exposure, with consequence for adipose-associated lipid storage. To evaluate systemic cues in mice housed at thermoneutral temperatures, we characterized the circulating lipidome, and show that sera are highly depleted in some HDL-associated phospholipids, specifically phospholipids containing the essential fatty acid, 18:2 linoleic acid, and its derivative, arachidonic acid (20:4) and related ether-phospholipids. Given the role of these fatty acids in inflammatory responses, we propose they may underlie the differences in disease progression observed at thermoneutrality.

Igniting adipocyte thermogenesis.

Maintenance of body temperature is intimately tied to energy expenditure and body weight regulation. In this issue of Cell, Li, Wang, et al. discovered that localized hyperthermia induces the thermogenic program to increase energy expenditure and decrease body weight in mice and humans.

Determination of tissue contributions to the circulating lipid pool in cold exposure via systematic assessment of lipid profiles.

Plasma lipid levels are altered in chronic conditions such as type 2 diabetes and cardiovascular disease as well as during acute stresses such as fasting and cold exposure. Advances in MS-based lipidomics have uncovered a complex plasma lipidome of more than 500 lipids that serve functional roles, including as energy substrates and signaling molecules. This plasma lipid pool is maintained through regulation of tissue production, secretion, and uptake. A major challenge in understanding the lipidome complexity is establishing the tissues of origin and uptake for various plasma lipids, which is valuable for determining lipid functions. Using cold exposure as an acute stress, we performed global lipidomics on plasma and in nine tissues that may contribute to the circulating lipid pool. We found that numerous species of plasma acylcarnitines (ACars) and ceramides (Cers) were significantly altered upon cold exposure. Through computational assessment, we identified the liver and brown adipose tissue as major contributors and consumers of circulating ACars, in agreement with our previous work. We further identified the kidney and intestine as novel contributors to the circulating ACar pool and validated these findings with gene expression analysis. Regression analysis also identified that the brown adipose tissue and kidney are interactors with the plasma Cer pool. Taken together, these studies provide an adaptable computational tool to assess tissue contribution to the plasma lipid pool. Our findings have further implications in understanding the function of plasma ACars and Cers, which are elevated in metabolic diseases.

Nanostructured graphitic carbon nitride based ultrasensing electrochemical biosensor for food toxin detection.

We report results of the studies related to the fabrication of thionine functionalized graphitic carbon nitride nanosheets based ultrasensing platform for food toxin (Aflatoxin B1, AfB1) detection. The synthesis of graphitic carbon nitride nanosheets (g-C3N4) was carried out by polycondensation of melamine followed by chemical exfoliation. Further, thionine was used for the functionalization of g-C3N4 (Thn/g-C3N4) and deposited electrophoretically onto the indium tin oxide (ITO) coated glass electrode. The fabricated Thn/g-C3N4/ITO electrode was covalently immobilized by EDC-NHS chemistry with anti-aflatoxin B1 (anti-AfB1) followed by blocking of non-specific sites using BSA molecules. For structural, morphological, functional and electrochemical properties analysis of synthesized nanomaterials and fabricated electrodes X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, atomic force microscopy and cyclic voltammetry techniques were used. The electrochemical response studies of the fabricated biosensing platform (BSA/anti-AfB1/Thn/g-C3N4/ITO) were carried out towards detection of AfB1 antigen using cyclic voltammetry technique. The obtained electrochemical results indicate that the fabricated biosensing electrode having ability to detect AfB1 with lower limit of detection of 0.328 fg mL-1, linear detection range in between 1 fg mL-1 to 1 ng mL-1, sensitivity of 4.85 µA log [ng-1 mL] cm-2 with stability upto 7 weeks.

Protein based biomarkers for non-invasive Covid-19 detection.

COVID-19 has become a substantial lethal disease worldwide, and early diagnosis is a significant concern for this virus. Currently, RT-PCR is being used worldwide for the detection of this virus with human to human transmission. Furthermore, the recent develop biosensor leading to others diagnosis approach but being invasive are painful and time taking. Another possibility can be protein-based biomarkers as an application of biosensors for detection and early diagnostics. Considering the other approach, that is, microfluidics-based biosensor, though being a non-invasive method, will be restricting virus transmission. This review commences with the recent develop biosensor for Covid-19 detection and listing down the available biomarkers with their secretion range comparison of normal to COVID-19 patients through clinical analysis in china and concludes with the future approach for the diagnosis.

Seasonal differences exist in the polyunsaturated fatty acid, mineral and antioxidant content of U.S. grass-finished beef.

There is increased consumer interest in grass-finished beef (GFB) with retail sales reaching $272 million in 2016. GFB contains higher omega-3 fatty acid levels compared to grain-finished beef, but variations in fatty acid (FA), mineral, and antioxidant content by producers and season is poorly documented. Hence, GFB samples from cattle finished in both fall and spring were obtained from four producers representing several US sub-regions. FAs were extracted using microwave-assisted extraction, derivatized to methyl-esters, and quantified using gas chromatography-mass spectrometry. Mineral content was quantified using coupled plasma mass-spectrometry and antioxidants were quantified via UV-absorption. Overall, total omega-3 FA content was greater in beef from cattle finished in the spring (13.4 mg/100g beef) than the fall (10.3; P<0.001). Additionally, α-tocopherol was present in greater amounts in spring-finished beef (259 vs. 223 ug/100g beef, P<0.001) as was the micromineral selenium (18.2 vs. 17.3ug/100g beef, P = 0.008). Despite using the same feed in fall and spring, cattle from producer 4 had higher total omega-3, omega-6, and total polyunsaturated fatty acids in spring compared to fall (P<0.010). These results suggest there are seasonal differences in omega-3 and omega-6 fatty acids, minerals and antioxidants in grass-finished beef independent of finishing diet.

Serum n-6 Fatty Acids are Positively Associated with Growth in 6-to-10-Year Old Ugandan Children Regardless of HIV Status-A Cross-Sectional Study.

Fatty acids (FAs) are crucial in child growth and development. In Uganda, antiretroviral therapy (ART) has drastically reduced perinatal human immunodeficiency virus (HIV) infection of infants, however, the interplay of FAs, ART, and HIV in relation to child growth is not well understood. To investigate this, serum was collected from 240 children between 6-10 years old in Uganda and analyzed for FAs using gas-chromatography mass-spectrometry. HIV status and anthropometric measurements were taken, and relationships with FAs were assessed. No significant differences in growth parameters or serum FAs were found between HIV uninfected children with and without exposure to ART. HIV positive children had significantly lower height-for-age-z-scores (HAZ) than uninfected children (p < 0.001). HIV-positive children had higher arachidonic acid than uninfected children (p = 0.003). Total omega-6 FAs were significantly associated with HAZ regardless of HIV status (p = 0.035). Mean total omega-3 FAs (2.90%) were low in this population compared to other cohorts in Africa. These results provide reference serum FA values for 6-10-year-old children in Uganda and may be used to inform lipid supplementation programs to promote child growth. Future studies should investigate the relationships between child growth trajectories in relation to HIV status and serum FAs.

Frontline Science: A reduction in DHA-derived mediators in male obesity contributes toward defects in select B cell subsets and circulating antibody.

Obesity dysregulates B cell populations, which contributes toward poor immunological outcomes. We previously reported that differing B cell subsets are lowered in the bone marrow of obese male mice. Here, we focused on how lipid metabolites synthesized from docosahexaenoic acid (DHA) known as specialized pro-resolving lipid mediators (SPMs) influence specific B cell populations in obese male mice. Metabololipidomics revealed that splenic SPM precursors 14-hydroxydocosahexaenoic acid (14-HDHA), 17-hydroxydocosahexaenoic acid (17-HDHA), and downstream protectin DX (PDX) were decreased in obese male C57BL/6J mice. Simultaneous administration of these mediators to obese mice rescued major decrements in bone marrow B cells, modest impairments in the spleen, and circulating IgG2c, which is pro-inflammatory in obesity. In vitro studies with B cells, flow cytometry experiments with ALOX5-/- mice, and lipidomic analyses revealed the lowering of 14-HDHA/17-HDHA/PDX and dysregulation of B cell populations in obesity was driven indirectly via B cell extrinsic mechanisms. Notably, the lowering of lipid mediators was associated with an increase in the abundance of n-6 polyunsaturated fatty acids, which have a high affinity for SPM-generating enzymes. Subsequent experiments revealed female obese mice generally maintained the levels of SPM precursors, B cell subsets, and antibody levels. Finally, obese human females had increased circulating plasma cells accompanied by ex vivo B cell TNFα and IL-10 secretion. Collectively, the data demonstrate that DHA-derived mediators of the SPM pathway control the number of B cell subsets and pro-inflammatory antibody levels in obese male but not female mice through a defect that is extrinsic to B cells.

Quantification of fatty acid and mineral levels of selected seeds, nuts, and oils in Northern Ghana.

The purpose of this study was to identify locally available foods that can be utilized by Northern Ghanaians to improve child growth status. An assortment of seeds, nuts and oils were collected from a local market, packaged in plastic containers, and shipped to the US for all analyses. Fatty acids (FAs) were extracted and derivatized to FA methyl esters prior to quantification by GC/MS. ANOVA were conducted on FA concentrations and Tukey's post hoc test was used to compare FA content. Food grade oils, particularly palm oil and shea butter, contained higher saturated and monounsaturated FAs than seeds or nuts. Soybean, was significantly higher in the essential omega-3 FA alpha-linolenic acid (2.98 mg/g), whereas neri seed (68.4 mg/g) and fermented dawadawa (seed; 56.3 mg/g) had significantly higher amounts of total polyunsaturated FAs than all other foods. Iron levels in soybean (353 mg/kg), neri (282 mg/kg) and fermented dawadawa (165 mg/kg) were also the highest of all foods. Together, these foods may be useful for future intervention to curb stunting and iron-deficiency anemia.

The role of the lipidome in obesity-mediated colon cancer risk.

Obesity is a state of chronic inflammation influenced by lipids such as fatty acids and their secondary oxygenated metabolites deemed oxylipids. Many such lipid mediators serve as potent signaling molecules of inflammation, which can further alter lipid metabolism and lead to carcinogenesis. For example, sphingosine-1-phosphate activates cyclooxygenase-2 in endothelial cells resulting in the conversion of arachidonic acid (AA) to prostaglandin E2 (PGE2). PGE2 promotes colon cancer cell growth. In contrast, the less studied path of AA oxygenation via cytochrome p450 enzymes produces epoxyeicosatetraenoic acids (EETs), whose anti-inflammatory properties cause shrinking of enlarged adipocytes, a characteristic of obesity, through the liberation of fatty acids. It is now thought that EET depletion occurs in obesity and may contribute to colon cell carcinogenesis. Meanwhile, gangliosides, a type of sphingolipid, are cell surface signaling molecules that contribute to the apoptosis of colon tumor cells. Many of these discoveries have been made recently and the mechanisms are still not fully understood, leading to an exciting new chapter of lipidomic research. In this review, mechanisms behind obesity-associated colon cancer are discussed with a focus on the role of small lipid signaling molecules in the process. Specifically, changes in lipid metabolite levels during obesity and the development of colon cancer, as well as novel biomarkers and targets for therapy, are discussed.

Association of whole blood n-6 fatty acids with stunting in 2-to-6-year-old Northern Ghanaian children: A cross-sectional study.

In Northern Ghana, 33% of children are stunted due to economic disparities. Dietary fatty acids (FA) are critical for growth, but whether blood FA levels are adequate in Ghanaian children is unknown. The objective of this study was to determine the association between whole blood FAs and growth parameters in Northern Ghanaian children 2-6 years of age. A drop of blood was collected on an antioxidant treated card and analyzed for FA composition. Weight and height were measured and z-scores were calculated. Relationships between FAs and growth parameters were analyzed by Spearman correlations, linear regressions, and factor analysis. Of the 307 children who participated, 29.7% were stunted and 8% were essential FA deficient (triene/tetraene ratio>0.02). Essential FA did not differ between stunted and non-stunted children and was not associated with height-for-age z-score (HAZ) or weight-for-age z-score (WAZ). In hemoglobin adjusted regression models, both HAZ and WAZ were positively associated with arachidonic acid (p≤0.01), dihomo-gamma-linolenic acid (DGLA, p≤0.05), docosatetraenoic acid (p≤0.01) and the ratio of DGLA/linoleic acid (p≤0.01). These data add to the growing body of evidence indicating n-6 FAs are critical in childhood linear growth. Our findings provide new insights into the health status of an understudied Northern Ghanaian population.