Hepatic inflammatory cytokine production can be regulated by modulating sphingomyelinase and ceramide synthase 6

CD36 deficiency protects lipopolysaccharide-induced sepsis via inhibiting CerS6-mediated endoplasmic reticulum stress

The type 2 scavenger receptor CD36 functions not only as a long chain fatty acid transporter, but also as a pro-inflammatory mediator. Ceramide is the simple N-acylated form of sphingosine and exerts distinct biological activity depending on its acyl chain length. Six ceramide synthases (CerS) in mammals determine the chain length of ceramide species, and CerS6 mainly produces C16-ceramide. Endotoxin-induced septic shock shows high mortality, but the pathophysiologic role of sphingolipids involved in this process has been hardly investigated. This paper aims to highlight the different role of CerS isoforms in endotoxin-induced inflammatory responses and the regulatory role of CD36 in CerS6 protein degradation with an emphasis as the potential therapeutic candidates in humans. Lipopolysaccharide (LPS), the endotoxin of the Gram-negative bacterial cell wall, was treated to induce endotoxin-induced inflammation both in vitro and in vivo. CerS6-derived C16-ceramide propagated LPS-induced inflammatory responses activating various intracellular signaling pathways, such as mitogen-activated protein kinase and nuclear factor-κB, resulting in the formation of inflammasome complex and pro-inflammatory cytokines. Mechanistically, CerS6-derived C16-ceramide augmented inflammatory responses via endoplasmic reticulum stress, and CerS6 protein stability was regulated by CD36. Finally, CerS6 protein expression and LPS-induced lethality were strikingly reduced in CD36 knockout mice. Collectively, our findings show that CerS6-derived C16-ceramide plays a pivotal role in endotoxin-induced inflammation and suggest CerS6 and its regulator CD36 as possible targets for therapy under life-threatening inflammation such as septic shock.

Integration of network pharmacology, metabolomics and lipidomics for clarifying the role of sphingolipid metabolism in the treatment of liver cancer by regorafenib

AIMS

Regorafenib, an FDA-approved drug for advanced primary liver cancer (PLC), could provide survival benefits for patients. However, markers for its therapeutic sensitivity are lacking. This study seeks to identify sensitive targets of regorafenib in PLC from the perspective of small molecular metabolites.

MATERIALS AND METHODS

Initiated with network pharmacology (NP) to map regorafenib's target landscape and metabolic regulatory network in liver cancer. Subsequently, regorafenib's impact on hepatoma cells was evaluated by flow cytometry, western blotting (WB) and cell viability assay. Advanced metabolomics and lipidomics were employed to elucidate regorafenib's metabolic reprogramming effects in liver cancer. Metabolic enzyme expression was assessed by WB, immunohistochemical and immunofluorescence assays. Ultimately, mendelian randomization (MR) analysis was utilized to investigate the potential causality of sphingolipid metabolism in hepatic cancer.

KEY FINDINGS

Regorafenib was observed to inhibit hepatoma cell proliferation and cell cycle progression at G0/G1 phase, resulting in significant alterations in sphingolipid levels. It promoted the significant accumulation of 16:0 dihydroceramide (16:0 dhCer) by upregulating ceramide synthase 6 (CERS6) expression and inhibiting dihydroceramide desaturase 1 (DEGS1) activity. The MR analysis revealed that DEGS1 was a risk factor for the development and progression of liver cancer, while cumulative 16:0 dhCer was a protective factor.

SIGNIFICANCE

Sphingolipids, particularly dhCer and regulatory enzymes, may be potential sensitive markers of regorafenib in the treatment of liver cancer, providing new insights for enhancing the treated efficacy of regorafenib in liver cancer.

Protaetia brevitarsis larvae extract protects against lipopolysaccharides-induced ferroptosis and inflammation by inhibiting acid sphingomyelinase

BACKGROUND/OBJECTIVES

Inflammation and ferroptosis are implicated in various diseases and lipopolysaccharides (LPS) have been linked with these disorders. Recently, many edible insects, such as Gryllus bimaculatus, Protaetia brevitarsis larvae (PB) and Tenebrio molitor larvae, have been recommended as alternative foods because they contain lots of nutritional sources. In this study, we explored the potential of PB extract in preventing LPS-induced inflammation and ferroptosis in Hep3B cells.

MATERIALS/METHODS

PB powder was extracted using 70% ethanol and applied to Hep3B cells. Co-treatment with LPS was conducted to induce ferroptosis and inflammation. The anti-inflammatory and anti-ferroptosis mechanisms of the PB extract were confirmed using Western blot, enzyme-linked immunosorbent assay, and real-time polymerase chain reaction analysis.

RESULTS

PB extract effectively prevented LPS-induced cell death and restored LPS-induced inflammatory cytokine production, NF-κB signaling, endoplasmic reticulum (ER) stress and ferroptosis. Interestingly, PB extract reduced LPS-induced ceramide increase and acid sphingomyelinase (ASMase) expression. The use of the ASMase inhibitor, desipramine, also demonstrated a reduction in these pathways, highlighting the pivotal role of ASMase in inflammation and ferroptosis. Treatment with each inhibitor revealed that ferroptosis causes ER stress and that NF-κB and MAP kinase pathways are involved in inflammation.

CONCLUSION

PB emerges as a potential functional food with inhibitory effects on LPS-induced inflammation and ferroptosis, making it a promising candidate for nutritional interventions.

Circulating sphingolipids and subclinical brain pathology: the cardiovascular health study

Background

Sphingolipids are implicated in neurodegeneration and neuroinflammation. We assessed the potential role of circulating ceramides and sphingomyelins in subclinical brain pathology by investigating their association with brain magnetic resonance imaging (MRI) measures and circulating biomarkers of brain injury, neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) in the Cardiovascular Health Study (CHS), a large and intensively phenotyped cohort of older adults.

Methods

Brain MRI was offered twice to CHS participants with a mean of 5 years between scans, and results were available from both time points in 2,116 participants (mean age 76 years; 40% male; and 25% APOE ε4 allele carriers). We measured 8 ceramide and sphingomyelin species in plasma samples and examined the associations with several MRI, including worsening grades of white matter hyperintensities and ventricular size, number of brain infarcts, and measures of brain atrophy in a subset with quantitative measures. We also investigated the sphingolipid associations with serum NfL and GFAP.

Results

In the fully adjusted model, higher plasma levels of ceramides and sphingomyelins with a long (16-carbon) saturated fatty acid were associated with higher blood levels of NfL [β = 0.05, false-discovery rate corrected P (PFDR) = 0.004 and β = 0.06, PFDR = < 0.001, respectively]. In contrast, sphingomyelins with very long (20- and 22-carbon) saturated fatty acids tended to have an inverse association with levels of circulating NfL. In secondary analyses, we found an interaction between ceramide d18:1/20:0 and sex (P for interaction = <0.001), such that ceramide d18:1/20:0 associated with higher odds for infarcts in women [OR = 1.26 (95%CI: 1.07, 1.49), PFDR = 0.03]. We did not observe any associations with GFAP blood levels, white matter grade, ventricular grade, mean bilateral hippocampal volume, or total brain volume.

Conclusion

Overall, our comprehensive investigation supports the evidence that ceramides and sphingomyelins are associated with increased aging brain pathology and that the direction of association depends on the fatty acid attached to the sphingosine backbone.

Neutral Sphingomyelinase 2 Inhibition Limits Hepatic Steatosis and Inflammation

Non-alcoholic fatty liver disease (NAFLD) is manifested by hepatic steatosis, insulin resistance, hepatocyte death, and systemic inflammation. Obesity induces steatosis and chronic inflammation in the liver. However, the precise mechanism underlying hepatic steatosis in the setting of obesity remains unclear. Here, we report studies that address this question. After 14 weeks on a high-fat diet (HFD) with high sucrose, C57BL/6 mice revealed a phenotype of liver steatosis. Transcriptional profiling analysis of the liver tissues was performed using RNA sequencing (RNA-seq). Our RNA-seq data revealed 692 differentially expressed genes involved in processes of lipid metabolism, oxidative stress, immune responses, and cell proliferation. Notably, the gene encoding neutral sphingomyelinase, SMPD3, was predominantly upregulated in the liver tissues of the mice displaying a phenotype of steatosis. Moreover, nSMase2 activity was elevated in these tissues of the liver. Pharmacological and genetic inhibition of nSMase2 prevented intracellular lipid accumulation and TNFα-induced inflammation in in-vitro HepG2-steatosis cellular model. Furthermore, nSMase2 inhibition ameliorates oxidative damage by rescuing PPARα and preventing cell death associated with high glucose/oleic acid-induced fat accumulation in HepG2 cells. Collectively, our findings highlight the prominent role of nSMase2 in hepatic steatosis, which could serve as a potential therapeutic target for NAFLD and other hepatic steatosis-linked disorders.

Emerging roles and therapeutic potentials of sphingolipids in pathophysiology: emphasis on fatty acyl heterogeneity

Sphingolipids not only exert structural roles in cellular membranes, but also act as signaling molecules in various physiological and pathological processes. A myriad of studies have shown that abnormal levels of sphingolipids and their metabolic enzymes are associated with a variety of human diseases. Moreover, blood sphingolipids can also be used as biomarkers for disease diagnosis. This review summarizes the biosynthesis, metabolism, and pathological roles of sphingolipids, with emphasis on the biosynthesis of ceramide, the precursor for the biosynthesis of complex sphingolipids with different fatty acyl chains. The possibility of using sphingolipids for disease prediction, diagnosis, and treatment is also discussed. Targeting endogenous ceramides and complex sphingolipids along with their specific fatty acyl chain to promote future drug development will also be discussed.

Inhibition of acid sphingomyelinase reduces reactive astrocyte secretion of mitotoxic extracellular vesicles and improves Alzheimer's disease pathology in the 5xFAD mouse

In Alzheimer's disease (AD), reactive astrocytes produce extracellular vesicles (EVs) that affect mitochondria in neurons. Here, we show that Aβ-induced generation of the sphingolipid ceramide by acid sphingomyelinase (A-SMase) triggered proinflammatory cytokine (C1q, TNF-α, IL-1α) release by microglia, which induced the reactive astrocytes phenotype and secretion of EVs enriched with ceramide. These EVs impeded the capacity of neurons to respond to energy demand. Inhibition of A-SMase with Arc39 and Imipramine reduced the secretion of cytokines from microglia, prompting us to test the effect of Imipramine on EV secretion and AD pathology in the 5xFAD mouse model. Brain derived-EVs from 5xFAD mice treated with Imipramine contained reduced levels of the astrocytic marker GFAP, ceramide, and Aβ and did not impair mitochondrial respiration when compared to EVs derived from untreated 5xFAD brain. Consistently, Imipramine-treated 5xFAD mice showed reduced AD pathology. Our study identifies A-SMase inhibitors as potential AD therapy by preventing cyotokine-elicited secretion of mitotoxic EVs from astrocytes.

Plasma C18:0-ceramide is a novel potential biomarker for disease severity in myasthenia gravis

Myasthenia gravis (MG) is an antibody-mediated autoimmune disorder characterized by fluctuation of fatigue and weakness of muscle. Due to the heterogeneity of the course of MG, available biomarkers for prognostic prediction are urgently needed. Ceramide (Cer) was reported to participate in immune regulation and many autoimmune diseases, but its effects on MG remain undefined. This study aimed to investigate the ceramides expression levels in MG patients and their potential as novel biomarkers of disease severity. Levels of plasma ceramides were determined by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Severity of disease was assessed by quantitative MG scores (QMGs), MG-specific activities of daily living scale (MG-ADLs) and 15-item MG quality of Life (MG-QOL15). The concentrations of serum interleukin-1β (IL-1β), IL-6, IL-17A, and IL-21 were determined by enzyme-linked immunosorbent assay (ELISA), and the proportions of circulating memory B cells and plasmablasts were detected by flow-cytometry assay. Four plasma ceramides levels we studied were detected higher in MG patients. And three of them (C16:0-Cer, C18:0-Cer, and C24:0-Cer) were positively associated with QMGs. In addition, receiver operating characteristic (ROC) analysis suggested that plasma ceramides have a good ability of differentiating MG from HCs. Importantly, only C18:0-Cer was shown to be positively associated with the concentration of serum IL and circulating memory B cells, and the decrease in plasma C18:0-Cer paralleled the clinical improvement of patients with MG. All together, our data suggest that ceramides may play an important role in the immunopathological mechanism of MG, and C18:0-Cer has the potential to be a novel biomarker for disease severity in MG.

Characterization and Roles of Membrane Lipids in Fatty Liver Disease

Obesity has reached global epidemic proportions and it affects the development of insulin resistance, type 2 diabetes, fatty liver disease and other metabolic diseases. Membrane lipids are important structural and signaling components of the cell membrane. Recent studies highlight their importance in lipid homeostasis and are implicated in the pathogenesis of fatty liver disease. Here, we discuss the numerous membrane lipid species and their metabolites including, phospholipids, sphingolipids and cholesterol, and how dysregulation of their composition and physiology contribute to the development of fatty liver disease. The development of new genetic and pharmacological mouse models has shed light on the role of lipid species on various mechanisms/pathways; these lipids impact many aspects of the pathophysiology of fatty liver disease and could potentially be targeted for the treatment of fatty liver disease.

A Rheostat of Ceramide and Sphingosine-1-Phosphate as a Determinant of Oxidative Stress-Mediated Kidney Injury

Reactive oxygen species (ROS) modulate sphingolipid metabolism, including enzymes that generate ceramide and sphingosine-1-phosphate (S1P), and a ROS-antioxidant rheostat determines the metabolism of ceramide-S1P. ROS induce ceramide production by activating ceramide-producing enzymes, leading to apoptosis, while they inhibit S1P production, which promotes survival by suppressing sphingosine kinases (SphKs). A ceramide-S1P rheostat regulates ROS-induced mitochondrial dysfunction, apoptotic/anti-apoptotic Bcl-2 family proteins and signaling pathways, leading to apoptosis, survival, cell proliferation, inflammation and fibrosis in the kidney. Ceramide inhibits the mitochondrial respiration chain and induces ceramide channel formation and the closure of voltage-dependent anion channels, leading to mitochondrial dysfunction, altered Bcl-2 family protein expression, ROS generation and disturbed calcium homeostasis. This activates ceramide-induced signaling pathways, leading to apoptosis. These events are mitigated by S1P/S1P receptors (S1PRs) that restore mitochondrial function and activate signaling pathways. SphK1 promotes survival and cell proliferation and inhibits inflammation, while SphK2 has the opposite effect. However, both SphK1 and SphK2 promote fibrosis. Thus, a ceramide-SphKs/S1P rheostat modulates oxidant-induced kidney injury by affecting mitochondrial function, ROS production, Bcl-2 family proteins, calcium homeostasis and their downstream signaling pathways. This review will summarize the current evidence for a role of interaction between ROS-antioxidants and ceramide-SphKs/S1P and of a ceramide-SphKs/S1P rheostat in the regulation of oxidative stress-mediated kidney diseases.

Low-grade elevation of palmitate and lipopolysaccharide synergistically induced β-cell damage via inhibition of neutral ceramidase

High concentrations of free fatty acids (FFAs) or lipopolysaccharide (LPS) could lead to β-cell apoptosis and dysfunction, while low-grade elevation of FFAs or LPS, which are more common in people with type 2 diabetes mellitus (T2DM) or obesity, have no obvious toxic effect on β-cells. Palmitate is a component closely related to metabolic disorders in FFAs. Recent studies have found that low-grade elevation of palmitate and LPS synergistically affects the sphingolipid signaling pathway by activating Toll-like receptor 4 (TLR4) and further enhances the expression of inflammatory cytokines in immune cells. Previous studies demonstrated that sphingolipids also played an important role in the occurrence and development of T2DM. This study aimed to investigate the synergistic effects of low-grade elevation of palmitate and LPS on viability, apoptosis and insulin secretion in the rat pancreatic β-cell line INS-1 or islets and the role of sphingolipids in this process. We showed that low-grade elevation of palmitate or LPS alone did not affect the viability, apoptosis, glucose-stimulated insulin secretion (GSIS) or intracellular insulin content of INS-1 cells or islets, while the combination of the two synergistically inhibited cell viability, induced apoptosis and decreased basal insulin secretion in INS-1 cells or islets. Treatment with palmitate and LPS markedly upregulated TLR4 protein expression and downregulated neutral ceramidase (NCDase) activity and protein expression. Additionally, low-grade elevation of palmitate and LPS synergistically induced a significant increase in ceramide and a decrease in sphingosine-1-phosphate. Blocking TLR4 signaling or overexpressing NCDase remarkably attenuated INS-1 cell injury induced by the combination of palmitate and LPS. However, inhibition of ceramide synthase did not ameliorate injury induced by palmitate and LPS. Overall, we show for the first time that low-grade elevation of palmitate and LPS synergistically induced β-cell damage by activating TLR4 signaling, inhibiting NCDase activity, and further modulating sphingolipid metabolism, which was different from a high concentration of palmitate-induced β-cell injury by promoting ceramide synthesis.

Inhibition of acid sphingomyelinase by imipramine abolishes the synergy between metabolic syndrome and periodontitis on alveolar bone loss

BACKGROUND AND OBJECTIVE

Clinical studies have shown that metabolic syndrome (MetS) exacerbates periodontitis. However, the underlying mechanisms remain largely unknown. Since our animal study has shown that high-fat diet-induced MetS exacerbates lipopolysaccharide (LPS)-stimulated periodontitis in mouse model and our in vitro study showed that acid sphingomyelinase (aSMase) plays a key role in the amplification of LPS-triggered pro-inflammatory response by palmitic acid (PA) in macrophages, we tested our hypothesis that inhibitor of aSMase attenuates MetS-exacerbated periodontitis in animal model. Furthermore, to explore the potential underlying mechanisms, we tested our hypothesis that aSMase inhibitor downregulates pro-inflammatory and pro-osteoclastogenic gene expression in macrophages in vitro.

MATERIAL AND METHODS

We induced MetS and periodontitis in C57BL/6 mice by feeding high-fat diet (HFD) and periodontal injection of A. actinomycetemcomitans LPS, respectively, and treated mice with imipramine, a well-established inhibitor of aSMase. Micro-computed tomography (micro-CT), tartrate-resistant acid phosphatase staining, histological and pathological evaluations as well as cell cultures were performed to evaluate alveolar bone loss, osteoclast formation, periodontal inflammation and pro-inflammatory gene expression.

RESULTS

Analysis of metabolic parameter showed that while HFD induced MetS by increasing bodyweight, insulin resistance, cholesterol and free fatty acids, imipramine reduced free fatty acids but had no significant effects on other metabolic parameters. MicroCT showed that either MetS or periodontitis significantly reduced bone volume fraction (BVF) of maxilla and the combination of MetS and periodontitis further reduced BVF. However, imipramine increased BVF in mice with both MetS and periodontitis to a level similar to that in mice with periodontitis alone, suggesting that imipramine abolished the synergy between MetS and periodontitis on alveolar bone loss. Consistently, results showed that imipramine inhibited osteoclast formation and periodontal inflammation in mice with both MetS and periodontitis. To elucidate the mechanisms by which imipramine attenuates MetS-exacerbated periodontitis, we showed that imipramine inhibited the upregulation of pro-inflammatory cytokines and transcription factor c-FOS as well as ceramide production by LPS plus PA in macrophages.

CONCLUSION

This study has shown that imipramine as an inhibitor of aSMase abolishes the synergy between MetS and periodontitis on alveolar bone loss in animal model and inhibits pro-inflammatory and pro-osteoclastogenic gene expression in macrophages in vitro. This study provides the first evidence that aSMase is a potential therapeutic target for MetS-exacerbated periodontitis.

Sex-specific plasma lipid profiles of ME/CFS patients and their association with pain, fatigue, and cognitive symptoms

Background

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex illness which disproportionally affects females. This illness is associated with immune and metabolic perturbations that may be influenced by lipid metabolism. We therefore hypothesized that plasma lipids from ME/CFS patients will provide a unique biomarker signature of disturbances in immune, inflammation and metabolic processes associated with ME/CFS.

Methods

Lipidomic analyses were performed on plasma from a cohort of 50 ME/CFS patients and 50 controls (50% males and similar age and ethnicity per group). Analyses were conducted with nano-flow liquid chromatography (nLC) and high-performance liquid chromatography (HPLC) systems coupled with a high mass accuracy ORBITRAP mass spectrometer, allowing detection of plasma lipid concentration ranges over three orders of magnitude. We examined plasma phospholipids (PL), neutral lipids (NL) and bioactive lipids in ME/CFS patients and controls and examined the influence of sex on the relationship between lipids and ME/CFS diagnosis.

Results

Among females, levels of total phosphatidylethanolamine (PE), omega-6 arachidonic acid-containing PE, and total hexosylceramides (HexCer) were significantly decreased in ME/CFS compared to controls. In males, levels of total HexCer, monounsaturated PE, phosphatidylinositol (PI), and saturated triglycerides (TG) were increased in ME/CFS patients compared to controls. Additionally, omega-6 linoleic acid-derived oxylipins were significantly increased in male ME/CFS patients versus male controls. Principal component analysis (PCA) identified three major components containing mostly PC and a few PE, PI and SM species—all of which were negatively associated with headache and fatigue severity, irrespective of sex. Correlations of oxylipins, ethanolamides and ME/CFS symptom severity showed that lower concentrations of these lipids corresponded with an increase in the severity of headaches, fatigue and cognitive difficulties and that this association was influenced by sex.

Conclusion

The observed sex-specific pattern of dysregulated PL, NL, HexCer and oxylipins in ME/CFS patients suggests a possible role of these lipids in promoting immune dysfunction and inflammation which may be among the underlying factors driving the clinical presentation of fatigue, chronic pain, and cognitive difficulties in ill patients. Further evaluation of lipid metabolism pathways is warranted to better understand ME/CFS pathogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03035-6.

Ethanol Induces Extracellular Vesicle Secretion by Altering Lipid Metabolism through the Mitochondria-Associated ER Membranes and Sphingomyelinases

Recent evidence pinpoints extracellular vesicles (EVs) as key players in intercellular communication. Given the importance of cholesterol and sphingomyelin in EV biology, and the relevance of mitochondria-associated endoplasmic reticulum membranes (MAMs) in cholesterol/sphingomyelin homeostasis, we evaluated if MAMs and sphingomyelinases (SMases) could participate in ethanol-induced EV release. EVs were isolated from the extracellular medium of BV2 microglia treated or not with ethanol (50 and 100 mM). Radioactive metabolic tracers combined with thin layer chromatography were used as quantitative methods to assay phospholipid transfer, SMase activity and cholesterol uptake/esterification. Inhibitors of SMase (desipramine and GW4869) and MAM (cyclosporin A) activities were also utilized. Our data show that ethanol increases the secretion and inflammatory molecule concentration of EVs. Ethanol also upregulates MAM activity and alters lipid metabolism by increasing cholesterol uptake, cholesterol esterification and SMase activity in microglia. Notably, the inhibition of either SMase or MAM activity prevented the ethanol-induced increase in EV secretion. Collectively, these results strongly support a lipid-driven mechanism, specifically via SMases and MAM, to explain the effect of ethanol on EV secretion in glial cells.

One-year results of a clinical trial of olipudase alfa enzyme replacement therapy in pediatric patients with acid sphingomyelinase deficiency

PURPOSE

To assess olipudase alfa enzyme replacement therapy for non-central nervous system manifestations of acid sphingomyelinase deficiency (ASMD) in children.

METHODS

This phase 1/2, international, multicenter, open-label trial (ASCEND-Peds/NCT02292654) administered intravenous olipudase alfa every 2 weeks with intrapatient dose escalation to 3 mg/kg. Primary outcome was safety through week 64. Secondary outcomes included pharmacokinetics, spleen and liver volumes, lung diffusing capacity (DLCO), lipid profiles, and height through week 52.

RESULTS

Twenty patients were enrolled: four adolescents (12-17 years), nine children (6-11 years), and seven infants/early child (1-5 years). Most adverse events were mild or moderate, including infusion-associated reactions (primarily urticaria, pyrexia, and/or vomiting) in 11 patients. Three patients had serious treatment-related events: one with transient asymptomatic alanine aminotransferase increases, another with urticaria and rash (antidrug antibody positive [ADA+]), and a third with an anaphylactic reaction (ADA+) who underwent desensitization and reached the 3 mg/kg maintenance dose. Mean splenomegaly and hepatomegaly improved by >40% (p < 0.0001). Mean % predicted DLCO improved by 32.9% (p = 0.0053) in patients able to perform the test. Lipid profiles and elevated liver transaminase levels normalized. Mean height Z-scores improved by 0.56 (p < 0.0001).

CONCLUSION

In this study in children with chronic ASMD, olipudase alfa was generally well-tolerated with significant, comprehensive improvements in disease pathology across a range of clinically relevant endpoints.

Potential Mechanism of S. baicalensis on Lipid Metabolism Explored via Network Pharmacology and Untargeted Lipidomics

Background

S. baicalensis, a traditional herb, has great potential in treating diseases associated with aberrant lipid metabolism, such as inflammation, hyperlipidemia, atherosclerosis and Alzheimer’s disease.

Aim of the Study

To elucidate the mechanism by which S. baicalensis modulates lipid metabolism and explore the medicinal effects of S. baicalensis at a holistic level.

Materials and Methods

The potential active ingredients of S. baicalensis and targets involved in regulating lipid metabolism were identified using a network pharmacology approach. Metabolomics was utilized to compare lipids that were altered after S. baicalensis treatment in order to identify significantly altered metabolites, and crucial targets and compounds were validated by molecular docking.

Results

Steroid biosynthesis, sphingolipid metabolism, the PPAR signaling pathway and glycerolipid metabolism were enriched and predicted to be potential pathways upon which S. baicalensis acts. Further metabolomics assays revealed 14 significantly different metabolites were identified as lipid metabolism-associated elements. After the pathway enrichment analysis of the metabolites, cholesterol metabolism and sphingolipid metabolism were identified as the most relevant pathways. Based on the results of the pathway analysis, sphingolipid and cholesterol biosynthesis and glycerophospholipid metabolism were regarded as key pathways in which S. baicalensis is involved to regulate lipid metabolism.

Conclusion

According to our metabolomics results, S. baicalensis may exert its therapeutic effects by regulating the cholesterol biosynthesis and sphingolipid metabolism pathways. Upon further analysis of the altered metabolites in certain pathways, agents downstream of squalene were significantly upregulated; however, the substrate of SQLE was surprisingly increased. By combining evidence from molecular docking, we speculated that baicalin, a major ingredient of S. baicalensis, may suppress cholesterol biosynthesis by inhibiting SQLE and LSS, which are important enzymes in the cholesterol biosynthesis pathway. In summary, this study provides new insights into the therapeutic effects of S. baicalensis on lipid metabolism using network pharmacology and lipidomics.

Gryllus bimaculatus extract protects against lipopolysaccharide and palmitate-induced production of proinflammatory cytokines and inflammasome formation

Inflammation and the inflammasome complex formation are associated with numerous diseases, and palmitates or lipopolysaccharides (LPS) have been identified as potential links between these disorders. Recently, edible insects such as the Gryllus bimaculatus (GB) and the larva of Tenebrio molitor have emerged as alternative food sources. In the present study, the effect of GB on LPS- or palmitate-induced production of inflammatory cytokines, the formation of the inflammasome complex, reactive oxygen species (ROS) generation, endoplasmic reticulum (ER) stress and cell death was investigated in RAW264.7 cells. The results revealed that GB extract downregulated the production of inflammatory cytokines (such as TNF-α, IL-1β and IL-6). Since the role of the MAP kinase and NF-κB signalling pathways in the production of inflammatory cytokines is well established, the translocation of p65 into the nucleus and the phosphorylation of IκB and MAP kinases were further examined. Both these processes were upregulated following LPS and palmitate treatment, but they were inhibited by the GB extract. Moreover, GB extract decreased LPS/palmitate-induced inflammasome complex formation (assessed via analysing the levels of the apoptosis-associated speck-like protein containing a caspase-recruitment domain, NOD-like receptor family pyrin domain containing 3, cleaved caspase-1 and IL-1β), the generation of ROS, ER stress and cell death. Treatment with SB203580 (a p38 inhibitor), SP600125 (a JNK inhibitor) and pyrrolidinedithiocarbamate ammonium (an NF-κB inhibitor) decreased the production of inflammatory cytokines, as well as helped in the recovery of LPS/palmitate-induced cell death. Overall, GB extract served an inhibitory role in LPS/palmitate-induced inflammation via inhibiting the MAP kinase and NF-κB signalling pathways, inflammasome complex formation, ROS generation, ER stress and cell death.

Integrative Analysis of MicroRNAs and mRNAs in LPS-Induced Macrophage Inflammation Based on Adipose Tissue Stem Cell Therapy

Severe inflammation can lead to multiple organ dysfunction syndrome, which has high mortality. Adipose-derived stem cells have been shown to affect the inflammatory response of macrophages. However, the molecular mechanism of the anti-inflammatory capacity of adipose-derived stem cells (ADSCs) remains to be understood. In the present study, a macrophage inflammation model was established by LPS, and treated with different volumes of ADSC supernatant. Then, we investigated the key genes in the LPS group and treatment group by RT-PCR, RNA sequencing technology, and bioinformatics analysis. A total of 26 miRNAs and 11,882 mRNAs were differentially expressed between them. The expression of 15 of the miRNAs (9 upregulated and 6 downregulated) was confirmed by RT-PCR. GO and KEGG pathway analyses of the targets of the 9 significantly upregulated miRNAs showed that they were related to immune system process, inflammatory response, lipopolysaccharide, and TNF-α, NF-κB, Toll-like receptor, and MAPK signaling pathways. Moreover, a miRNA-mRNA network also revealed 8 important genes (Mapkapk2, Sepp1, Cers6, Snn, ZfP568, Ccdc93, Pofut1, Pik3cd). We finally confirmed the expression of these 8 targeted genes by performing the RT-PCR analysis. This study may provide a new understanding of the molecular mechanism of ADSCs in the inflammatory response related to multiple miRNAs and mRNAs.

Screening for Susceptibility-Related Factors and Biomarkers of Xianling Gubao Capsule-Induced Liver Injury

Although increasing reports from the literature on herbal-related hepatotoxicity, the identification of susceptibility-related factors and biomarkers remains challenging due to idiosyncratic drug-induced liver injury (IDILI). As a well-known Chinese medicine prescription, Xianling Gubao Capsule (XLGB) has attracted great attention due to reports of potential liver toxicity. But the mechanism behind it is difficult to determine. In this paper, we found that XLGB-induced liver injury belongs to IDILI through the analysis of clinical liver injury cases. In toxicological experiment assessment, co-exposure to XLGB and non-toxic dose of lipopolysaccharide (LPS) could cause evident liver injury as manifested by significantly increased plasma alanine aminotransferase activity and obvious liver histological damage. However, it failed to induce observable liver injury in normal rats, suggesting that mild immune stress may be a susceptibility factor for XLGB-induced idiosyncratic liver injury. Furthermore, plasma cytokines were determined and 15 cytokines (such as IL-1β, IFN-γ, and MIP-2α etc) were acquired by receiver operating characteristic (ROC) curves analysis. The expression of these 15 cytokines in LPS group was significantly up-regulated in contrast to the normal group. Meanwhile, the metabolomics profile showed that mild immune stress caused metabolic reprogramming, including sphingolipid metabolism, phenylalanine metabolism, and glycerophospholipid metabolism. 8 potential biomarkers (such as sphinganine, glycerophosphoethanolamine, and phenylalanine etc.) were identified by correlation analysis. Therefore, these results suggested that intracellular metabolism and immune changes induced by mild immune stress may be important susceptibility mechanisms for XLGB IDILI.

Adoptive Transfer of Ceramide Synthase 6 Deficient Splenocytes Reduces the Development of Colitis

Sphingolipids regulate critical cellular processes including inflammation. Ceramide, which serves a central role in sphingolipid metabolism, is generated by six ceramide synthases (CerS) that differ in substrate specificity. CerS6 preferentially generates C₁₆-ceramide and its mRNA is highly expressed in immune tissues. In this study we analyzed how deficiency of CerS6 impacts on the development of colitis using an adoptive transfer model. Adoptive transfer of CerS6-deficient splenocytes, which have significantly decreased levels of C₁₆-ceramide, showed that CerS6-deficiency protected against the development of colitis. However, adoptively transferred cells isolated from the lamina propria of the large intestine from wild type or CerS6-deficient groups showed no differences in the percentages of immune-suppressive regulatory T cells, pro-inflammatory Th17 cells, or their ability to express IL-17. In vitro polarization of wild type or CerS6-deficient splenocytes also revealed no defects in the development of T cell subsets. Our data suggest that protection from colitis following adoptive transfer of CerS6-deficient splenocytes maybe related to their ability to migrate and proliferate in vivo rather than subset development or cytokine expression.