Inflammasome-mediated secretion of IL-1β in human monocytes through TLR2 activation; modulation by dietary fatty acids

Plant-based antioxidant peptides: impact on oxidative stress and gut microbiota

Plant-based peptides can be obtained from natural and climate-friendly sources. These peptides show various bioactivities including antioxidant activity. Oxidative stress has an impact on the gut microbiota causing inflammation, insulin resistance, osteoporosis, cancer, and several chronic diseases like type 2 diabetes, arthritis, hypertension, and atherosclerosis. Therefore, antioxidant peptides may significantly affect oxidative stress as a potential alternative to conventional medication. The production of antioxidant peptides from plant-based protein sources through conventional and innovative approaches may provide promising strategies to improve gut microbiota. Recent studies in plant-based antioxidant peptides (PBAP) focus on their advanced identification and characterization techniques, structure-activity relationship, improvement of extraction and purification, cellular and molecular mechanisms, specific health applications in preventing and managing conditions with gut microbiota, and commercial applications in nutraceuticals. Short-chain fatty acids and reactive sulfur species are specific gut-derived metabolites that can improve metabolic function by modulating oxidative stress and the immune system. This review highlights the influence of food oxidants on the gut microbiota and PBAP-induced modulation of gut microbiota. Moreover, the production of PBAP and the challenges in their application will be discussed.

Serum lipid and plasma fatty acid profiles in PTSD patients and healthy individuals: Associations with symptoms, cognitive function, and inflammatory markers

Increasing evidence suggests that posttraumatic stress disorder (PTSD), a serious mental health condition, is associated with physical health problems. Lipid-related molecules are crucial for central nervous system functions associated with PTSD symptoms; however, case-control studies exploring the relationship between PTSD and lipid-related molecules are scarce. We examined 68 civilian PTSD patients and 97 healthy controls, evaluating PTSD symptoms, childhood maltreatment history, suicidality, and cognitive functions. Cholesterol, triglycerides, and inflammation-related marker levels were analyzed in serum, while fatty acid levels were measured in plasma. Compared to controls, patients exhibited significantly lower high-density lipoprotein cholesterol and n-6 linoleic acid levels, alongside higher saturated palmitic acid levels and the triene-to-tetraene (T/T) ratio. PTSD symptoms, particularly hyperarousal, were significantly positively correlated with n-6 γ-linolenic, n-6 dihomo-γ-linolenic, and n-9 mead acid levels, and the T/T ratio. Cognitive functions were significantly positively correlated with n-3 docosahexaenoic acid and total n-3 fatty acid levels, and negatively correlated with saturated lauric, palmitic, and total saturated fatty acid levels. Suicidality was significantly positively correlated with dihomo-γ-linolenic acid, mead acid levels, and the T/T ratio, and negatively correlated with polyunsaturated fatty acid (PUFA) levels. Inflammation-related marker levels were significantly correlated with higher palmitic, n-9 oleic, and total n-9 fatty acid levels, and lower linoleic acid and PUFA levels. Latent profile analysis (LPA) revealed distinct subgroups associated with unique fatty acid profiles. These lipid-related alterations may improve the understanding of PTSD pathophysiology. Distinct fatty acid profiles identified by LPA may help subtype PTSD patients and guide nutrition-based personalized treatment strategies.

Mesenchymal stromal cells can block palmitate training of macrophages via cyclooxygenase-2 and interleukin-1 receptor antagonist

Innate training of macrophages can be beneficial for the clearance of pathogens. However, for certain chronic conditions, innate training can have detrimental effects due to an excessive production of pro-inflammatory cytokines. Obesity is a condition that is associated with a range of increased pro-inflammatory training stimuli including the free fatty acid palmitate. Mesenchymal stromal cells (MSCs) are powerful immunomodulators and known to suppress inflammatory macrophages via a range of soluble factors. We show that palmitate training of murine bone-marrow-derived macrophages and human monocyte-derived macrophages (MDMs) results in an increased production of TNFα and IL-6 upon stimulation with lipopolysaccharide and is associated with epigenetic remodeling. Palmitate training led to metabolic changes, however, MSCs did not alter the metabolic profile of human MDMs. Using a transwell system, we demonstrated that human bone marrow MSCs block palmitate training in both murine and human macrophages suggesting the involvement of secreted factors. MSC disruption of the training process occurs through more than one pathway. Suppression of palmitate-enhanced TNFα production is associated with cyclooxygenase-2 activity in MSCs, while secretion of interleukin-1 receptor antagonist by MSCs is required to suppress palmitate-enhanced IL-6 production in MDMs.

Molecular characteristics of organic matters in PM2.5 associated with upregulation of respiratory virus infection in vitro

The extent to which organic matters (OM) in PM2.5 affect virus infections and the key organic molecules involved in this process remain unclear. Herein, this study utilized ultra-high resolution mass spectrometry coupled with in vitro experiments to identify the organic molecules associated with respiratory virus infection for the first time. Water-soluble organic matters (WSOM) and water-insoluble organic matters (WIOM) were separated from PM2.5 samples collected at the urban area of Guangzhou, China. Their molecular compositions were analyzed using Fourier transform ion cyclotron resonance mass spectrometry. Subsequently, in vitro experiments were conducted to explore the impact of WSOM and WIOM exposure on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pseudo-virus infection in A549 cells. Results revealed that WSOM and WIOM respectively promoted 1.7 to 2.1-fold and 1.9 to 3.5-fold upregulation of SARS-CoV-2 pseudo-virus infection in a concentration-dependent manner (at 25 to 100 μg mL-1) compared to the virus-only control group. Partial least squares model analysis indicated that the increased virus infection was likely related to phthalate ester and nitro-aromatic molecules in WSOM, as well as LipidC molecules with aliphatic and olefinic structures in WIOM. Interestingly, the molecules responsible for upregulating SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE2) expression and virus infection differed. Thus, it was concluded that ACE2 upregulation alone may not fully elucidate the mechanisms underlying increased susceptibility to virus infection. The findings highlight the critical importance of aromatic and lipid molecules found in OM in relation to respiratory virus infection.

Exploring the potential of omega-3 fatty acids in acne patients: A prospective intervention study

BACKGROUND

Omega-3 fatty acids (ω-3 FA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), are essential nutrients known for their anti-inflammatory properties, which involve reducing pro-inflammatory cytokines, eicosanoids, and insulin-like growth factor-1. This suggests their potential to alleviate acne severity, especially when deficits are present.

AIMS

To elevate EPA/DHA levels in acne patients through dietary intervention and supplementation, observing subsequent clinical effects.

METHODS

Over 16 weeks, 60 patients without prescription medication (n = 23 acne comedonica [AC], n = 37 acne papulopustulosa [AP]) adhered to a Mediterranean diet, incorporating oral algae-derived ω-3 FA supplementation (600 mg DHA/300 mg EPA week 1-8, 800 mg DHA/400 mg EPA week 8-16). At four visits (V1-V4), blood EPA/DHA levels were tracked using the HS-omega 3 index® (EPA/DHA (%) of total identified fatty acids in erythrocytes; target 8%-11%, deficit <8%, severe deficit <4%), alongside clinical assessments and standardized questionnaires.

RESULTS

At baseline, 98.3% of patients had an EPA/DHA deficit, with the mean HS-omega 3 index® rising from 4.9% at V1 to 8.3% at V4 (p < 0.001). AC showed significantly higher indices than AP at V4 (p = 0.035). Objective improvements in both inflammatory and non-inflammatory lesions were observed (p < 0.001). While self-reported appearance worsened in four patients, overall quality of life improved (p < 0.001), particularly in AP. Dietary triggers were more clearly defined than beneficial foods. Intake of cow's milk and dairy products reduced (p < 0.001). Compliance was good; no adverse events were reported.

CONCLUSION

Many acne patients have a ω-3 FA deficit. The HS-omega 3 index® can be increased by a Mediterranean diet and oral supplementation with algae-derived ω-3 FA. Acne severity improved significantly in patients with target ω-3 FA levels.

Obesity aggravates the role of C-reactive protein on knee pain: A cross-sectional analysis with NHANES data

OBJECTIVE

To examine the relationship between C-reactive protein (CRP) and knee pain, and further explore whether this association is mediated by obesity.

METHODS

The population was derived from 1999 to 2004 National Health and Nutrition Examination Survey. Logistic regression was used to analyze the relationship between CRP and knee pain in three different models, and the linear trend was analyzed. A restricted cubic spline model to assess the nonlinear dose-response relationship between CRP and knee pain. Mediation analyses were used to assess the potential mediating role of obesity. Subgroup analyses and sensitivity analyses were performed to ensure robustness.

RESULTS

Compared with adults with lower CRP (first quartile), those with higher CRP had higher risks of knee pain (odds ratio 1.39, 95% confidence interval 1.12-1.72 in third quartile; 1.56, 1.25-1.95 in fourth quartile) after adjusting for covariates (except body mass index [BMI]), and the proportion mediated by BMI was 76.10% (p < .001). BMI and CRP were linear dose-response correlated with knee pain. The odds ratio for those with obesity compared with normal to knee pain was 2.27 (1.42-3.65) in the first quartile of CRP, 1.99 (1.38-2.86) in the second, 2.15 (1.38-3.33) in the third, and 2.92 (1.72-4.97) in the fourth.

CONCLUSION

Obesity mediated the systemic inflammation results in knee pain in US adults. Moreover, higher BMI was associated with higher knee pain risk in different degree CRP subgroups, supporting an important role of weight loss in reducing knee pain caused by systemic inflammation.

Understanding Macrophage Complexity in Metabolic Dysfunction-Associated Steatotic Liver Disease: Transitioning from the M1/M2 Paradigm to Spatial Dynamics

Metabolic dysfunction-associated steatotic liver disease (MASLD) encompasses metabolic dysfunction-associated fatty liver (MASL) and metabolic dysfunction-associated steatohepatitis (MASH), with MASH posing a risk of progression to cirrhosis and hepatocellular carcinoma (HCC). The global prevalence of MASLD is estimated at approximately a quarter of the population, with significant healthcare costs and implications for liver transplantation. The pathogenesis of MASLD involves intrahepatic liver cells, extrahepatic components, and immunological aspects, particularly the involvement of macrophages. Hepatic macrophages are a crucial cellular component of the liver and play important roles in liver function, contributing significantly to tissue homeostasis and swift responses during pathophysiological conditions. Recent advancements in technology have revealed the remarkable heterogeneity and plasticity of hepatic macrophage populations and their activation states in MASLD, challenging traditional classification methods like the M1/M2 paradigm and highlighting the coexistence of harmful and beneficial macrophage phenotypes that are dynamically regulated during MASLD progression. This complexity underscores the importance of considering macrophage heterogeneity in therapeutic targeting strategies, including their distinct ontogeny and functional phenotypes. This review provides an overview of macrophage involvement in MASLD progression, combining traditional paradigms with recent insights from single-cell analysis and spatial dynamics. It also addresses unresolved questions and challenges in this area.

Genome-wide meta-analysis identifies novel loci conferring risk of acne vulgaris

Acne vulgaris is a common chronic skin disorder presenting with comedones, cystic structures forming within the distal hair follicle, and in most cases additionally with inflammatory skin lesions on the face and upper torso. We performed a genome-wide association study and meta-analysis of data from 34,422 individuals with acne and 364,991 controls from three independent European-ancestry cohorts. We replicated 19 previously implicated genome-wide significant risk loci and identified four novel loci [11q12.2 (FADS2), 12q21.1 (LGR5), 17q25.3 (FASN), and 22q12.1 (ZNRF3-KREMEN1)], bringing the total number of reported acne risk loci to 50. Our meta-analysis results explain 9.4% of the phenotypic variance of acne. A polygenic model of acne risk variants showed that individuals in the top 5% of the risk percentiles had a 1.62-fold (95% CI 1.47-1.78) increased acne risk relative to individuals with average risk (20-80% on the polygenic risk score distribution). Our findings highlight the Wnt and MAPK pathways as key factors in the genetic predisposition to acne vulgaris, together with the effects of genetic variation on the structure and maintenance of the hair follicle and pilosebaceous unit. Two novel loci, 11q12.2 and 17q25.3, contain genes encoding key enzymes involved in lipid biosynthesis pathways.

Benfotiamine improves dystrophic pathology and exercise capacity in mdx mice by reducing inflammation and fibrosis

Duchenne Muscular Dystrophy (DMD) is a progressive and fatal neuromuscular disease. Cycles of myofibre degeneration and regeneration are hallmarks of the disease where immune cells infiltrate to repair damaged skeletal muscle. Benfotiamine is a lipid soluble precursor to thiamine, shown clinically to reduce inflammation in diabetic related complications. We assessed whether benfotiamine administration could reduce inflammation related dystrophic pathology. Benfotiamine (10 mg/kg/day) was fed to male mdx mice (n = 7) for 15 weeks from 4 weeks of age. Treated mice had an increased growth weight (5-7 weeks) and myofibre size at treatment completion. Markers of dystrophic pathology (area of damaged necrotic tissue, central nuclei) were reduced in benfotiamine mdx quadriceps. Grip strength was increased and improved exercise capacity was found in mdx treated with benfotiamine for 12 weeks, before being placed into individual cages and allowed access to an exercise wheel for 3 weeks. Global gene expression profiling (RNAseq) in the gastrocnemius revealed benfotiamine regulated signalling pathways relevant to dystrophic pathology (Inflammatory Response, Myogenesis) and fibrotic gene markers (Col1a1, Col1a2, Col4a5, Col5a2, Col6a2, Col6a2, Col6a3, Lum) towards wildtype levels. In addition, we observed a reduction in gene expression of inflammatory gene markers in the quadriceps (Emr1, Cd163, Cd4, Cd8, Ifng). Overall, these data suggest that benfotiamine reduces dystrophic pathology by acting on inflammatory and fibrotic gene markers and signalling pathways. Given benfotiamine's excellent safety profile and current clinical use, it could be used in combination with glucocorticoids to treat DMD patients.

Oral Administration of Limosilactobacillus reuteri KBL346 Ameliorates Influenza Virus A/PR8 Infection in Mouse

Influenza virus infection is an important public-health concern because of its high transmissibility and potential for severe complications. To mitigate the severity and complications of influenza, probiotics containing Lactobacillus are used and generally recognized as safe. We evaluated the anti-influenza effect of Limosilactobacillus reuteri (L. reuteri) KBL346, isolated from the fecel sample of healthy South Koreans, in mice. BALB/c mice were orally administered live and heat-inactivated L. reuteri KBL346. After infection with influenza virus (A/Puerto Rico/8/34) 0.5 times the 50% lethal dose (LD50), body weight loss was improved and recovery was accelerated. Furthermore, L. reuteri KBL346 improved body weight loss and survival rate of mice infected with 4 times the LD50 of influenza virus. Heat-inactivated L. reuteri KBL346 reduced the viral titer in the lung and the plasma immunoglobulin G level. Expression levels of genes encoding inflammatory cytokines, such as interferon-γ and toll-like receptor 2 (Tlr2), were decreased in the lung tissues of mice administered L. reuteri KBL346. Live and heat-inactivated L. reuteri KBL346 increased the expression level of Adamts4, which promotes recovery after infection, and decreased that of Tlr2. The α-diversity of the gut microbiome was modulated by the administration of L. reuteri KBL346. In addition, the structure of the gut microbial community differed according to the degree of weight loss. L. reuteri KBL346 has the potential to alleviate disease severity and improve histopathological changes in mice infected with influenza A/PR8, suggesting its efficacy as a probiotic against influenza infection.

Metabolomic analysis reveals macrophage metabolic reprogramming and polarization under different nutritional cues

BACKGROUND AND AIMS

Obesity-induced chronic inflammation and metabolic abnormalities are highly relevant to the functional dysregulation of macrophages, especially under obese conditions. Hyperglycemia and hyperlipidemia, central to obesity, directly alter macrophage activity. However, the impacts of different nutritional cues on the intricate metabolic networks in macrophages remain unclear.

MATERIALS AND METHODS

In this study, we employed metabolomic approaches to examine the metabolic responses of macrophages to high glucose, high fat and their coexistence, aiming to delineate the molecular mechanisms of nutritional factors on macrophage activation and obesity-related diseases from a metabolic perspective.

RESULTS

Our findings revealed that different nutritional conditions could reprogram key metabolism in macrophages. Additionally, we identified a metabolite derived from macrophages, Long-Chain Phosphatidylcholine (LPC), which exerts beneficial effects on obese mice. It ameliorates the obesity phenotype and improves glucose metabolism profiles. This discovery suggests that LPC has a significant therapeutic potential in the context of obesity-induced metabolic dysfunctions. Our study unveils the metabolic phenotype of macrophages in high-fat and high-sugar environments and uncovers a macrophage-derived metabolite that significantly ameliorates the obesity phenotype.

CONCLUSION

This finding reveals a potential dialogue mechanism between macrophages and adipocytes, shedding light on the complex interplay of immune and metabolic systems in obesity. This discovery not only enhances our understanding of obesity's underlying mechanisms but also opens up new avenues for therapeutic interventions targeting macrophage-adipocyte interactions.

Grape seed extract prevents oestrogen deficiency-induced bone loss by modulating the gut microbiota and metabolites

Proanthocyanidin-rich grape seed extract (GSE) has been shown to have the potential to protect bones, although the underlying mechanism remains unknown. The current study aims to explore GSE's preventive and therapeutic impact on bone loss induced by oestrogen deficiency and the underlying mechanism through the gut microbiota (GM) and metabolomic responses. In oestrogen-deficient ovariectomized (OVX) mice, GSE ameliorated bone loss by inhibiting the expansion of bone marrow adipose tissue (BMAT), restoring BMAT lipolysis and promoting bone formation. GSE regulated OVX-induced GM dysbiosis by reducing the abundance of opportunistic pathogenic bacteria, such as Alistipes, Turicibacter and Romboutsia, while elevating the abundance of beneficial bacteria, such as Bifidobacterium. The modified GM primarily impacted lipid and amino acid metabolism. Furthermore, the serum metabolites of GSE exhibited a significant enrichment in lipid metabolism. In summary, GSE shows potential as a functional food for preventing oestrogen deficiency-induced bone loss by modulating GM and metabolite-mediated lipid metabolism.

Eating away cancer: the potential of diet and the microbiome for shaping immunotherapy outcome

The gut microbiome (GMB) plays a substantial role in human health and disease. From affecting gut barrier integrity to promoting immune cell differentiation, the GMB is capable of shaping host immunity and thus oncogenesis and anti-cancer therapeutic response, particularly with immunotherapy. Dietary patterns and components are key determinants of GMB composition, supporting the investigation of the diet-microbiome-immunity axis as a potential avenue to enhance immunotherapy response in cancer patients. As such, this review will discuss the role of the GMB and diet on anti-cancer immunity. We demonstrate that diet affects anti-cancer immunity through both GMB-independent and GMB-mediated mechanisms, and that different diet patterns mold the GMB's functional and taxonomic composition in distinctive ways. Dietary modulation therefore shows promise as an intervention for improving cancer outcome; however, further and more extensive research in human cancer populations is needed.

Metabolite-derived damage-associated molecular patterns in immunological diseases

Damage-associated molecular patterns (DAMPs) are typically derived from the endogenous elements of necrosis cells and can trigger inflammatory responses by activating DAMPs-sensing receptors on immune cells. Failure to clear DAMPs may lead to persistent inflammation, thereby contributing to the pathogenesis of immunological diseases. This review focuses on a newly recognized class of DAMPs derived from lipid, glucose, nucleotide, and amino acid metabolic pathways, which are then termed as metabolite-derived DAMPs. This review summarizes the reported molecular mechanisms of these metabolite-derived DAMPs in exacerbating inflammation responses, which may attribute to the pathology of certain types of immunological diseases. Additionally, this review also highlights both direct and indirect clinical interventions that have been explored to mitigate the pathological effects of these DAMPs. By summarizing our current understanding of metabolite-derived DAMPs, this review aims to inspire future thoughts and endeavors on targeted medicinal interventions and the development of therapies for immunological diseases.

Loss of ceramide synthase 5 inhibits the development of experimentally induced aortic valve stenosis

AIM

Inflammation and calcification are hallmarks in the development of aortic valve stenosis (AVS). Ceramides mediate inflammation and calcification in the vascular tissue. The highly abundant d18:1,16:0 ceramide (C16) has been linked to increased cardiovascular mortality and obesity. In this study, we investigate the role of ceramide synthase 5 (CerS5), a critical enzyme for C16 ceramide synthesis, in the development of AVS, particularly in conjunction with a high-fat/high-cholesterol diet (Western diet, WD).

METHODS

We used wild-type (WT) and CerS5-/- mice on WD or normal chow in a wire injury model. We measured the peak velocity to determine AVS development and performed histological analysis of the aortic valve area, immune cell infiltration (CD68 staining), and calcification (von Kossa). In vitro experiments involved measuring the calcification of human aortic valvular interstitial cells (VICs) and evaluating cytokine release from THP-1 cells, a human leukemia monocytic-like cell line, following CerS5 knockdown.

RESULTS

CerS5-/- mice showed a reduced peak velocity compared to WT only in the experiment with WD. Likewise, we observed reduced immune cell infiltration and calcification in the aortic valve of CerS5-/- mice, but only on WD. In vitro, calcification was reduced after knockdown of CerS5 in VICs, while THP-1 cells exhibited a decreased inflammatory response following CerS5 knockdown.

CONCLUSION

We conclude that CerS5 is an important mediator for the development of AVS in mice on WD and regulates critical pathophysiological hallmarks of AVS formation. CerS5 is therefore an interesting target for pharmacological therapy and merits further investigation.

Lipotoxicity and immunometabolism in ischemic acute kidney injury: current perspectives and future directions

Dysregulated lipid metabolism is implicated in the pathophysiology of a range of kidney diseases. The specific mechanisms through which lipotoxicity contributes to acute kidney injury (AKI) remain poorly understood. Herein we review the cardinal features of lipotoxic injury in ischemic kidney injury; lipid accumulation and mitochondrial lipotoxicity. We then explore a new mechanism of lipotoxicity, what we define as "immunometabolic" lipotoxicity, and discuss the potential therapeutic implications of targeting this lipotoxicity using lipid lowering medications.

Triggers for the onset and recurrence of psoriasis: a review and update

Psoriasis is an immune-mediated inflammatory skin disease, involving a complex interplay between genetic and environmental factors. Previous studies have demonstrated that genetic factors play a major role in the pathogenesis of psoriasis. However, non-genetic factors are also necessary to trigger the onset and recurrence of psoriasis in genetically predisposed individuals, which include infections, microbiota dysbiosis of the skin and gut, dysregulated lipid metabolism, dysregulated sex hormones, and mental illness. Psoriasis can also be induced by other environmental triggers, such as skin trauma, unhealthy lifestyles, and medications. Understanding how these triggers play a role in the onset and recurrence of psoriasis provides insights into psoriasis pathogenesis, as well as better clinical administration. In this review, we summarize the triggers for the onset and recurrence of psoriasis and update the current evidence on the underlying mechanism of how these factors elicit the disease. Video Abstract.

Association of different cell types and inflammation in early acne vulgaris

Acne vulgaris, one of the most common skin diseases, is a chronic cutaneous inflammation of the upper pilosebaceous unit (PSU) with complex pathogenesis. Inflammation plays a central role in the pathogenesis of acne vulgaris. During the inflammatory process, the innate and adaptive immune systems are coordinately activated to induce immune responses. Understanding the infiltration and cytokine secretion of differential cells in acne lesions, especially in the early stages of inflammation, will provide an insight into the pathogenesis of acne. The purpose of this review is to synthesize the association of different cell types with inflammation in early acne vulgaris and provide a comprehensive understanding of skin inflammation and immune responses.

Peiminine Exerts Its Anti-Acne Effects by Regulating the NF-κB Pathway

Peiminine is the main natural alkaloid compound extracted from the Chinese herb Fritillaria. Although peiminine is known for its antioxidant and anti-inflammatory effects in conditions such as mastitis and arthritis, its impact on inflammation induced by Cutibacterisum acnes (C. acnes) has not been explored. The aim of this study was to investigate the effect of peiminine on C. acnes-induced inflammatory responses in the skin and to identify the underlying mechanism involved. We discovered that peiminine inhibits the C. acnes-induced expression of inflammatory mediators such as pro-interleukin-1β (pro-IL-1β), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in mouse bone marrow-derived macrophages (BMDMs). Peiminine suppressed the activation of nuclear factor-kappa B (NF-κB) without affecting the activation of mitogen-activated protein kinase (MAPK) pathways such as JNK, ERK, and p38 MAPK. In addition, we found that peiminine suppressed inflammatory cytokine expression and ameliorated histological symptoms in C. acnes-induced mouse skin. Our study is the first to provide evidence that peiminine has an inhibitory effect on acne, and it points toward the potential of incorporating peiminine into cosmetic and pharmaceutical formulations for acne treatment.

GC/MS and LC/MS serum metabolomic analysis of Chinese LN patients

China, being a densely populated nation, faces a substantial economic burden due to a high incidence of lupus nephritis (LN) cases. The concealed onset of LN has resulted in many individuals have missed the optimal timing for treatment. The aim of the research is to study the serum metabolomics of Chinese LN patients using gas chromatography (GC)/mass spectrometry (MS) and liquid chromatography (LC)/MS to identify potential diagnostic markers. Fifty LN patients and fifty normal controls, matched for Body Mass Index (BMI) and age, were selected. Serum analysis was conducted using GC/MS and LC/MS, followed by multivariate statistical analysis. Various multidimensional analyses, including principal component analysis, partial least squares discrimination analysis, and orthogonal partial least squares discrimination analysis, along with one-dimensional analyses such as t-tests, were performed. Metabolites with variable importance in projection value > 1 and a p-value < 0.05 were considered critical biomarkers for LN. Furthermore, identified biomarkers delineated relevant metabolic pathways, and a metabolic pathway map was obtained from the database. Forty-one metabolites were identified as potential LN biomarkers, primarily associated with immune regulation, energy metabolism, intestinal microbial metabolism, renal damage, and oxidative stress. The potential for diagnosing LN and other diseases through metabolomics is demonstrated. Future research should explore larger sample sizes, metabolomic comparisons across different diseases and health states, and integration of metabolomics with clinical diagnostics. Such studies will enhance the understanding of metabolomics in medical diagnosis and provide robust support for its practical application.

Palmitate Stimulates Expression of the von Willebrand Factor and Modulates Toll-like Receptors Level and Activity in Human Umbilical Vein Endothelial Cells (HUVECs)

An increased concentration of palmitate in circulation is one of the most harmful factors in obesity. The von Willebrand factor (vWF), a protein involved in haemostasis, is produced and secreted by the vascular endothelium. An increased level of vWF in obese patients is associated with thrombosis and cardiovascular disease. The aim of this study was to investigate a palmitate effect on vWF in endothelial cells and understand the mechanisms of palmitate-activated signalling. Human umbilical vein endothelial cells (HUVECs) incubated in the presence of palmitate, exhibited an increased VWF gene expression, vWF protein maturation, and stimulated vWF secretion. Cardamonin, a Nuclear Factor kappa B (NF-κB) inhibitor, abolished the palmitate effect on VWF expression. The inhibition of Toll-like receptor (TLR) 2 with C29 resulted in the TLR4 overactivation in palmitate-treated cells. Palmitate, in the presence of TLR4 inhibitor TAK-242, leads to a higher expression of TLR6, CD36, and TIRAP. The silencing of TLR4 resulted in an increase in TLR2 level and vice versa. The obtained results indicate a potential mechanism of obesity-induced thrombotic complication caused by fatty acid activation of NF-κB signalling and vWF upregulation and help to identify various compensatory mechanisms related to TLR4 signal transduction.

Innate Immune System Regulated by Stimulator of Interferon Genes, a Cytosolic DNA Sensor, Regulates Endothelial Function

BACKGROUND

Sterile inflammation caused by metabolic disorders impairs endothelial function; however, the underlying mechanism by which hyperglycemia induces inflammation remains obscure. Recent studies have suggested that stimulator of interferon genes (STING), a key cytosolic DNA sensor in the innate immune system, contributes to the pathogenesis of inflammatory diseases. This study examines the role of the STING in endothelial dysfunction in streptozotocin-induced diabetic mice.

METHODS AND RESULTS

Injection of streptozotocin promoted the expression of STING and DNA damage markers in the aorta of wild-type mice. Streptozotocin elevated blood glucose and lipid levels in both wild-type and STING-deficient mice, which showed no statistical differences. Genetic deletion of STING ameliorated endothelial dysfunction as determined by the vascular relaxation in response to acetylcholine (P<0.001) and increased endothelial nitric oxide synthase phosphorylation in the aorta (P<0.05) in STZ-injected mice. Endothelium-independent vascular response to sodium nitroprusside did not differ. Treatment with a direct STING agonist, cyclic GMP-AMP, or mitochondrial DNA increased inflammatory molecule expression (eg, VCAM1 and IFNB) and decreased endothelial nitric oxide synthase phosphorylation in human umbilical vein endothelial cells, partially through the STING pathway. Cyclic GMP-AMP significantly impaired endothelial function of aortic segments obtained from wild-type mice, which was ameliorated in the presence of C-176, a STING inhibitor, or a neutralizing interferon-β antibody. Furthermore, the administration of C-176 ameliorated endothelial dysfunction in STZ-induced diabetic mice (P<0.01).

CONCLUSIONS

The DNA damage response regulated by STING impairs endothelial function. STING signaling may be a potential therapeutic target of endothelial dysfunction caused by hyperglycemia.

Mechanisms underlying HIV-associated cognitive impairment and emerging therapies for its management

People living with HIV are affected by the chronic consequences of neurocognitive impairment (NCI) despite antiretroviral therapies that suppress viral replication, improve health and extend life. Furthermore, viral suppression does not eliminate the virus, and remaining infected cells may continue to produce viral proteins that trigger neurodegeneration. Comorbidities such as diabetes mellitus are likely to contribute substantially to CNS injury in people living with HIV, and some components of antiretroviral therapy exert undesirable side effects on the nervous system. No treatment for HIV-associated NCI has been approved by the European Medicines Agency or the US Food and Drug Administration. Historically, roadblocks to developing effective treatments have included a limited understanding of the pathophysiology of HIV-associated NCI and heterogeneity in its clinical manifestations. This heterogeneity might reflect multiple underlying causes that differ among individuals, rather than a single unifying neuropathogenesis. Despite these complexities, accelerating discoveries in HIV neuropathogenesis are yielding potentially druggable targets, including excessive immune activation, metabolic alterations culminating in mitochondrial dysfunction, dysregulation of metal ion homeostasis and lysosomal function, and microbiome alterations. In addition to drug treatments, we also highlight the importance of non-pharmacological interventions. By revisiting mechanisms implicated in NCI and potential interventions addressing these mechanisms, we hope to supply reasons for optimism in people living with HIV affected by NCI and their care providers.

Multiple TLRs elicit alternative NLRP3 inflammasome activation in primary human monocytes independent of RIPK1 kinase activity

The canonical NOD-like receptor family pyrin domain containing 3 (NLRP3) pathway involves a priming step to induce pro-IL-1β followed by a secondary signal such as K+ efflux to activate inflammasome formation. This then leads to the maturation of IL-1β and the formation of gasdermin D (GSDMD) pores that initiate pyroptosis and mediate IL-1β release. In contrast, primary human monocytes also engage an alternative pathway in response to toll-like receptor (TLR) 4 activation, without the need for a secondary signal. Data from a monocyte-like cell line suggest that the alternative pathway functions via the TLR adaptor protein TIR-domain-containing adapter-inducing interferon-β (TRIF), receptor-interacting protein kinase 1 (RIPK1), FAS-associated death domain (FADD) and caspase-8 upstream of NLRP3 activation, but in the absence of K+ efflux or pyroptosis. Usage of the alternative pathway by other members of the TLR family that induce IL-1β but do not signal through TRIF, has yet to be explored in primary human monocytes. Furthermore, the mechanism by which IL-1β is released from monocytes remains unclear. Therefore, this study investigated if the alternative NLRP3 inflammasome pathway is initiated following activation of TLRs other than TLR4, and if GSDMD was necessary for the release of IL-1β. Monocytes were stimulated with ligands that activate TLR1/2, TLR2/6, TLR4 and TLR7 and/or TLR8 (using a dual ligand). Similar to TLR4, all of the TLRs investigated induced IL-1β release in a NLRP3 and caspase-1 dependent manner, indicating that TRIF may not be an essential upstream component of the alternative pathway. Furthermore, inhibition of RIPK1 kinase activity had no effect on IL-1β release. Although IL-1β was released independently of K+ efflux and pyroptosis, it was significantly reduced by an inhibitor of GSDMD. Therefore, it is feasible that low level GSDMD pore formation may facilitate the release of IL-1β from the cell, but not be present in sufficient quantities to initiate pyroptosis. Together these data suggest that the alternative pathway operates independently of RIPK1 kinase activity, downstream of diverse TLRs including TLR4 in primary human monocytes and supports the potential for IL-1β release via GSDMD pores alongside other unconventional secretory pathways.

Macrophage metabolism in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) and its inflammatory and often progressive subtype nonalcoholic steatohepatitis (NASH), have emerged as significant contributors to hepatic morbidity worldwide. The pathophysiology of NAFLD/NASH is multifaceted, variable, and remains incompletely understood. The pivotal role of liver-resident and recruited macrophages in the pathogenesis of NAFLD and NASH is widely acknowledged as a crucial factor in innate immunity. The remarkable plasticity of macrophages enables them to assume diverse activation and polarization states, dictated by their immunometabolism microenvironment and functional requirements. Recent studies in the field of immunometabolism have elucidated that alterations in the metabolic profile of macrophages can profoundly influence their activation state and functionality, thereby influencing various pathological processes. This review primarily focuses on elucidating the polarization and activation states of macrophages, highlighting the correlation between their metabolic characteristics and the transition from pro-inflammatory to anti-inflammatory phenotypes. Additionally, we explore the potential of targeting macrophage metabolism as a promising therapeutic approach for the management of NAFLD/NASH.

Dysregulation of inflammasome activation in glioma

Gliomas are the most common brain tumors characterized by complicated heterogeneity. The genetic, molecular, and histological pathology of gliomas is characterized by high neuro-inflammation. The inflammatory microenvironment in the central nervous system (CNS) has been closely linked with inflammasomes that control the inflammatory response and coordinate innate host defenses. Dysregulation of the inflammasome causes an abnormal inflammatory response, leading to carcinogenesis in glioma. Because of the clinical importance of the various physiological properties of the inflammasome in glioma, the inflammasome has been suggested as a promising treatment target for glioma management. Here, we summarize the current knowledge on the contribution of the inflammasomes in glioma and therapeutic insights. Video Abstract.

Titanium dioxide nanoparticles: revealing the mechanisms underlying hepatotoxicity and effects in the gut microbiota

Numerous studies in recent years have questioned the safety of oral exposure to titanium dioxide nanoparticles (TiO2 NPs). TiO2 NPs are not only likely to accumulate in the gastrointestinal tract, but they are also found to penetrate the body circulation and reach distant organs. The liver, which is considered to be a target organ for nanoparticles, is of particular concern. TiO2 NPs accumulate in the liver and cause oxidative stress and inflammatory reactions, resulting in pathological damage. The impact of TiO2 NPs on liver aspartate aminotransferase (AST) and alanine aminotransferase (ALT) was studied using a meta-analysis. According to the findings, TiO2 NPs exposure can cause an elevation in AST and ALT levels in the blood. Furthermore, TiO2 NPs are eliminated mostly through feces, and their lengthy residence in the gut exposes them to microbiota. The gut microbiota is also dysbiotic due to titanium dioxide's antibacterial capabilities. This further leads to changes in the amount of microbiota metabolites, which can reach the liver with blood circulation and trigger hepatotoxicity through the gut-liver axis. This review examines the gut-liver axis to assess the effects of gut microbiota dysbiosis on the liver to provide suggestions for assessing the gut-hepatotoxicity of TiO2 NPs.

Fatty Acids Composition and HIV Infection: Altered Levels of n-6 Polyunsaturated Fatty Acids Are Associated with Disease Progression

Fatty acids (FAs) are important regulators of immune responses and innate defense mechanisms. We hypothesized that disturbed FA metabolism could contribute to the progression of HIV infection. Plasma levels of 45 FAs were analyzed with gas chromatography in healthy controls and HIV-infected patients with regard to Mycobacterium avium complex (MAC) infection. In vitro, we assessed MAC-PPD-induced release of inflammatory cytokines in peripheral and bone marrow mononuclear cells (PBMC and BMMC) according to levels of n-6 polyunsaturated fatty acids (PUFAs). While plasma saturated FAs were higher in HIV infection, PUFAs, and in particular the n-6 PUFA arachidonic acid (AA), were lower in patients with advanced disease. The ratio between AA and precursor dihomo-γ-linolenic acid, reflecting Δ5-desaturase activity, was markedly lower and inversely correlated with plasma HIV RNA levels in these patients. Depletion of AA was observed prior to MAC infection, and MAC-PPD-induced release of TNF and IL-6 in PBMC and BMMC was lower in patients with low plasma AA. Our findings suggest that dysregulated metabolism of n-6 PUFAs may play a role in the progression of HIV infection. While high AA may contribute to chronic inflammation in asymptomatic HIV-infected patients, low AA seems to increase the susceptibility to MAC infection in patients with advanced disease.

Effects of different obesogenic diets on joint integrity, inflammation and intermediate monocyte levels in a rat groove model of osteoarthritis

Introduction: Obesogenic diets aggravate osteoarthritis (OA) by inducing low-grade systemic inflammation, and diet composition may affect OA severity. Here, we investigated the effect of diet on joint damage and inflammation in an OA rat model. Methods: Wistar-Han rats (n = 24) were fed a chow, a high-fat (HF) diet, or a high-fat/high-sucrose (HFS) for 24 weeks. OA was induced unilaterally 12 weeks after the diet onset by groove surgery, and compared to sham surgery or no surgical intervention (contralateral limb). Knee OA severity was determined by OARSI histopathology scoring system. At several timepoints monocyte populations were measured using flow cytometry, and joint macrophage response was determined via CD68 immunohistochemistry staining. Results: Groove surgery combined with HF or HFS diet resulted in higher OARSI scores, and both HF and HFS diet showed increased circulating intermediate monocytes compared to chow fed rats. Additionally, in the HFS group, minimal damage by sham surgery resulted in an increased OARSI score. HFS diet resulted in the largest metabolic dysregulation, synovial inflammation and increased CD68 staining in tibia epiphysis bone marrow. Conclusion: Obesogenic diets resulted in aggravated OA development, even with very minimal joint damage when combined with the sucrose/fat-rich diet. We hypothesize that diet-induced low-grade inflammation primes monocytes and macrophages in the blood, bone marrow, and synovium, resulting in joint damage when triggered by groove OA inducing surgery. When the metabolic dysregulation is larger, as observed here for the HFS diet, the surgical trigger required to induce joint damage may be smaller, or even redundant.

The Effects of a High-Fat Diet on Inflammatory Bowel Disease

The interactions among diet, intestinal immunity, and microbiota are complex and play contradictory roles in inflammatory bowel disease (IBD). An increasing number of studies has shed light on this field. The intestinal immune balance is disrupted by a high-fat diet (HFD) in several ways, such as impairing the intestinal barrier, influencing immune cells, and altering the gut microbiota. In contrast, a rational diet is thought to maintain intestinal immunity by regulating gut microbiota. In this review, we emphasize the crucial contributions made by an HFD to the gut immune system and microbiota.

NOD-like Receptors-Emerging Links to Obesity and Associated Morbidities

Obesity and its associated metabolic morbidities have been and still are on the rise, posing a major challenge to health care systems worldwide. It has become evident over the last decades that a low-grade inflammatory response, primarily proceeding from the adipose tissue (AT), essentially contributes to adiposity-associated comorbidities, most prominently insulin resistance (IR), atherosclerosis and liver diseases. In mouse models, the release of pro-inflammatory cytokines such as TNF-alpha (TNF-α) and interleukin (IL)-1β and the imprinting of immune cells to a pro-inflammatory phenotype in AT play an important role. However, the underlying genetic and molecular determinants are not yet understood in detail. Recent evidence demonstrates that nucleotide-binding and oligomerization domain (NOD)-like receptor (NLR) family proteins, a group of cytosolic pattern recognition receptors (PRR), contribute to the development and control of obesity and obesity-associated inflammatory responses. In this article, we review the current state of research on the role of NLR proteins in obesity and discuss the possible mechanisms leading to and the outcomes of NLR activation in the obesity-associated morbidities IR, type 2 diabetes mellitus (T2DM), atherosclerosis and non-alcoholic fatty liver disease (NAFLD) and discuss emerging ideas about possibilities for NLR-based therapeutic interventions of metabolic diseases.

AGEs-RAGE-KCa3.1 pathway mediates palmitic acid-induced migration of PBMCs from patients with type 2 diabetes

Type 2 diabetes mellitus (T2DM) is characterized by chronic low-grade systemic inflammation. Tissue infiltration by monocyte migration contributes to the pathogenesis of vascular complications in T2DM. We studied the role of intermediate-conductance Ca²⁺-activated K⁺ (K_Ca3.1) channels in the palmitic acid (PA)-induced migration of peripheral blood mononuclear cells (PBMCs) from T2DM patients and the influence of advanced glycation endproducts (AGEs). A total of 49 T2DM patients and 33 healthy subjects was recruited into this study. Using flow cytometry and Western blotting analysis as well as cell migration assay, we found that there was a significant decrease in frequency of T lymphocytes and monocytes in CD45⁺ leukocyte population. PA at 100 μM stimulated migration of PBMCs from T2DM individuals, which was inhibited by the specific K_Ca3.1 channel blocker TRAM-34 (1 μM). The PBMC migration was positively correlated with glycosylated hemoglobin A1 chain (HbA1c) level of T2DM patients, an indicator of AGEs, and PBMCs with higher level of HbA1c showed upregulated expression of toll-like receptor (TLR) 2/4 and K_Ca3.1 channels. In THP-1 cells, AGEs at 200 μg/ml increased protein expression of TLR 2/4 and K_Ca3.1 channels, and were synergistically involved in PA-induced migration through receptors of AGEs (RAGE)-mediated K_Ca3.1 upregulation. In conclusion, in PBMCs of T2DM patients, AGEs promotes PA-induced migration via upregulation of TLR2/4 and K_Ca3.1 channels.

The HDM allergen orchestra and its cysteine protease maestro: Stimulators of kaleidoscopic innate immune responses

House dust mite (HDM) encloses an explosive cocktail of allergenic proteins sensitizing hundreds of millions of people worldwide. To date, the innate cellular and molecular mechanism(s) orchestrating the HDM-induced allergic inflammation remains partially deciphered. Understanding the kaleidoscope of HDM-induced innate immune responses is hampered by (1) the large complexity of the HDM allergome with very diverse functional bioreactivities, (2) the perpetual presence of microbial compounds (at least LPS, β-glucan, chitin) promoting as well pro-Th2 innate signaling pathways and (3) multiple cross-talks involving structural, neuronal and immune cells. The present review provides an update on the innate immune properties, identified so far, of multiple HDM allergen groups. Experimental evidence highlights the importance of HDM allergens displaying protease or lipid-binding activities on the initiation of the allergic responses. Specifically, group 1 HDM cysteine proteases are considered as the key initiators of the allergic response through their capacities to impair the epithelial barrier integrity, to stimulate the release of pro-Th2 danger-associated molecular patterns (DAMPs) in epithelial cells, to produce super-active forms of IL-33 alarmin and to mature thrombin leading to Toll-like receptor 4 (TLR4) activation. Remarkably, the recently evidenced primary sensing of cysteine protease allergens by nociceptive neurons confirms the critical role of this HDM allergen group in the early events leading to Th2 differentiation.

Autophagy: A Cellular Guardian against Hepatic Lipotoxicity

Lipotoxicity is a phenomenon of lipid-induced cellular injury in nonadipose tissue. Excess of free saturated fatty acids (SFAs) contributes to hepatic injury in nonalcoholic fatty liver disease (NAFLD), which has been growing at an unprecedented rate in recent years. SFAs and their derivatives such as ceramides and membrane phospholipids have been shown to induce intrahepatic oxidative damage and ER stress. Autophagy represents a cellular housekeeping mechanism to counter the perturbation in organelle function and activation of stress signals within the cell. Several aspects of autophagy, including lipid droplet assembly, lipophagy, mitophagy, redox signaling and ER-phagy, play a critical role in mounting a strong defense against lipotoxic lipid species within the hepatic cells. This review provides a succinct overview of our current understanding of autophagy-lipotoxicity interaction and its pharmacological and nonpharmacological modulation in treating NAFLD.

The interplay between nonalcoholic fatty liver disease and atherosclerotic cardiovascular disease

Therapeutic approaches that lower circulating low-density lipoprotein (LDL)-cholesterol significantly reduced the burden of cardiovascular disease over the last decades. However, the persistent rise in the obesity epidemic is beginning to reverse this decline. Alongside obesity, the incidence of nonalcoholic fatty liver disease (NAFLD) has substantially increased in the last three decades. Currently, approximately one third of world population is affected by NAFLD. Notably, the presence of NAFLD and particularly its more severe form, nonalcoholic steatohepatitis (NASH), serves as an independent risk factor for atherosclerotic cardiovascular disease (ASCVD), thus, raising interest in the relationship between these two diseases. Importantly, ASCVD is the major cause of death in patients with NASH independent of traditional risk factors. Nevertheless, the pathophysiology linking NAFLD/NASH with ASCVD remains poorly understood. While dyslipidemia is a common risk factor underlying both diseases, therapies that lower circulating LDL-cholesterol are largely ineffective against NASH. While there are no approved pharmacological therapies for NASH, some of the most advanced drug candidates exacerbate atherogenic dyslipidemia, raising concerns regarding their adverse cardiovascular consequences. In this review, we address current gaps in our understanding of the mechanisms linking NAFLD/NASH and ASCVD, explore strategies to simultaneously model these diseases, evaluate emerging biomarkers that may be useful to diagnose the presence of both diseases, and discuss investigational approaches and ongoing clinical trials that potentially target both diseases.

Hadh deficiency induced oligoasthenoteratozoospermia through the TNF-α/Bcl-2 pathway in male mice

The process of spermatogenesis is a complex and delicate process that is still not fully understood. In this study, we examined the role of fatty acid oxidase 3-hydroxy acyl CoA dehydrogenase (HADH) in maintaining normal spermatogenesis in mice. In male mice, ablation of the Hadh gene using CRISPR/Cas9 technology arrested spermatocyte meiosis, increased multinucleated giant germ cells and vacuoles in seminiferous tubules, and accompanied with acrosomal dysplasia. Hadh^-/- male mice showed the typical features of oligoasthenoteratozoospermia (OAT), including decreased sperm concentration and motility and increased sperm abnormalities. Next, we explored the molecular events in the testes of the mutant mice. We found fatty acids accumulated in the testis of Hadh^-/- mice. And also, inflammatory factors TNF-α, IL-1β, and IL-6 were significantly increased, apoptosis-related protein Bcl-2 was decreased, and Bax and cleaved-Caspase3 were increased in Hadh^-/- male mice testis. After using etanercept, a specific inhibitor of TNF-α, testis injury caused by Hadh knockout was significantly alleviated, the sperm quality and motility were improved, and germ cell apoptosis was reduced. So our study demonstrated that Hadh deletion caused an increase in fatty acids. The accumulated fatty acids further induced testicular inflammation and germ cell apoptosis through the TNF-α/Bcl-2 signaling pathway, finally resulting in OAT in the Hadh^-/- mice. Inhibiting TNF-α may be used as a new treatment approach for testicular inflammation and OAT.

Association between low-fat diet and liver cancer risk in 98,455 participants: Results from a prospective study

BACKGROUND

Low-fat diet reduces the risk of chronic metabolic diseases such as obesity and diabetes, which exhibit overlapping mechanisms with liver cancer. However, the association between low-fat diet and liver cancer risk remains unclear.

AIM

To investigate whether adherence to low-fat diet is associated with a reduced risk of liver cancer in a prospective study.

MATERIALS AND METHODS

Data of participants in this study were collected from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. A low-fat diet score was calculated to reflect adherence to low-fat dietary pattern, with higher scores indicating greater adherence. Cox regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for liver cancer incidence with adjustment for potential covariates. Restricted cubic spline model was used to characterize liver cancer risk across the full range of the low-fat diet score. Prespecified subgroup analyses were used to identify potential impact modifiers. Sensitivity analyses were performed to test the robustness of this association.

RESULTS

A total of 98,455 participants were included in the present analysis. The mean (standard deviation) age, low-fat diet score, and follow-up time were 65.52 (5.73) years, 14.99 (6.27) points, and 8.86 (1.90) years, respectively. During 872639.5 person-years of follow-up, 91 liver cancers occurred, with an overall incidence rate of 0.01 cases per 100 person-years. In the fully adjusted Cox model, the highest versus the lowest quartile of low-fat diet score was found to be associated with a reduced risk of liver cancer (HR Q4 vs. Q1: 0.458; 95% CI: 0.218, 0.964; P = 0.035 for trend), which remained associated through a series of sensitivity analyses. The restricted cubic spline model showed a linear dose-response association between low-fat diet score and liver cancer incidence (p = 0.482 for non-linear). Subgroup analyses did not show significant interaction between low-fat diet score and potential impact modifiers in the incidence of liver cancer.

CONCLUSION

In this study, low-fat diet score is associated with reduced liver cancer risk in the US population, indicating that adherence to low-fat diet may be helpful for liver cancer prevention. Future studies should validate our findings in other populations.

Metabolism Characteristics of Mycoplasma pneumoniae Infection in Asthmatic Children

PURPOSE

Studies have shown that Mycoplasma pneumoniae (Mp) infection can aggravate symptoms in asthmatics. However, the mechanism by which Mp infection exacerbates asthma remains unclear. Metabolomics can help identify the mechanism of Mp aggravating asthma in children, thereby providing more a potential target for improving clinical treatment programs. In this article, we analyzed the metabolic level of patients to explain how Mp aggravates asthma in children.

METHODS

We divided the subjects into the asthma, Mp infection, asthma combined with Mp infection and healthy groups. Patients' peripheral blood was collected for metabolic and interaction analysis. Cytokine levels were measured via serum and exhaled breath condensate (EBC).

RESULTS

A total of 150 participating subjects were divided into four groups after exclusion. We found out that there were different metabolic pathways between the healthy and disease groups. The major pathways of both asthma and asthma combined with Mp infection were valine, leucine and isoleucine biosynthesis; malate-aspartate shuttle was the main differential pathway for Mp infection. Moreover, even though three disease groups involved 81 metabolites at the same time, compared with asthma combined with Mp infection, 2 single disease groups still involved different amino acid pathways (phenylalanine, tyrosine and tryptophan biosynthesis; valine, leucine and isoleucine biosynthesis). Interaction analysis showed that Mp infection in asthmatic patients not only activated cytokines, but also activated Toll-like receptors (TLRs) 2 and 6. Finally, the levels of interleukin (IL)-4, IL-8, IL-13 and tumor necrosis factor-α in EBC with asthma combined with Mp infection were significantly higher than the 2 single disease groups.

CONCLUSIONS

Mp infection in asthmatic children can cause changes in the levels of various amino acids in the body, which were enriched in the pathways such as valine, leucine and isoleucine biosynthesis. Palmitic acid can activate TLR2, and iloprost reduces IL-10 levels, ultimately leading to the increased airway inflammation.

Expanding role of deoxyribonucleic acid-sensing mechanism in the development of lifestyle-related diseases

In lifestyle-related diseases, such as cardiovascular, metabolic, respiratory, and kidney diseases, chronic inflammation plays a causal role in their pathogenesis; however, underlying mechanisms of sterile chronic inflammation are not well-understood. Previous studies have confirmed the damage of cells in these organs in the presence of various risk factors such as diabetes, dyslipidemia, and cigarette smoking, releasing various endogenous ligands for pattern recognition receptors. These studies suggested that nucleic acids released from damaged tissues accumulate in these tissues, acting as an endogenous ligand. Undamaged DNA is an integral factor for the sustenance of life, whereas, DNA fragments, especially those from pathogens, are potent activators of the inflammatory response. Recent studies have indicated that inflammatory responses such as the production of type I interferon (IFN) induced by DNA-sensing mechanisms which contributes to self-defense system in innate immunity participates in the progression of inflammatory diseases by the recognition of nucleic acids derived from the host, including mitochondrial DNA (mtDNA). The body possesses several types of DNA sensors. Toll-like receptor 9 (TLR9) recognizes DNA fragments in the endosomes. In addition, the binding of DNA fragments in the cytosol activates cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase (cGAS), resulting in the synthesis of the second messenger cyclic GMP-AMP (cGAMP). The binding of cGAMP to stimulator of interferon genes (STING) activates NF-κB and TBK-1 signaling and consequently the production of many inflammatory cytokines including IFNs. Numerous previous studies have demonstrated the role of DNA sensors in self-defense through the recognition of DNA fragments derived from pathogens. Beyond the canonical role of TLR9 and cGAS-STING, this review describes the role of these DNA-sensing mechanism in the inflammatory responses caused by endogenous DNA fragments, and in the pathogenesis of lifestyle-related diseases.

Feasibility of conducting a randomized, placebo-controlled study assessing whether omega-3 fatty acids prevent gout flares when starting urate-lowering treatment

Objective

The aim was to test the feasibility of a randomized controlled trial exploring whether omega-3 fatty acid supplementation limits gout flares during treat-to-target urate-lowering treatment (T2T-ULT).

Methods

Adults with at least one gout flare in the past 12 months and serum urate (SU) ≥360 μmol/l were recruited from general practices (primary method) and randomly assigned 1:1 to receive omega-3 fatty acid supplementation (4 g/day) or placebo for 28 weeks. At week 5, participants began T2T-ULT. The primary outcome was drop-out rate. Secondary outcomes were recruitment rate, outcome data completeness, the number, severity and duration of gout flares between weeks 5 and 28, and study drug compliance.

Results

Ninety-five per cent of randomized participants (n = 60) completed all study visits. The primary method recruitment rate was 2.2%. Fifty and 42 participants achieved SU &lt; 360 and 300 μmol/l (6 and 5 mg/dl), respectively. The number of gout flares [median (interquartile range): active 1 (0–2) and placebo 1 (0–2)], flare duration [mean (s.d.): active 7.00 (4.52) days and placebo 7.06 (8.14) days] and time to first flare [hazard ratio (95% CI) 0.97 (0.50, 1.86)] were comparable between both arms. Study drug compliance was high and comparable in both arms [median (interquartile range) returned capsule count: active 57 (26–100) and placebo 58 (27–154)]; red blood cell omega-3 fatty acid index increased twofold in the active arm and remained unchanged in the control arm.

Conclusion

The study demonstrated feasibility and provided useful metrics for conducting a community-based gout flare prophylaxis trial.

Study registration

ISRCTN; https://www.isrctn.com/; ISRCTN79392964.

Docosahexaenoic Acid Ameliorates the Toll-Like Receptor 22-Triggered Inflammation in Fish by Disrupting Lipid Raft Formation

BACKGROUND

Although dietary DHA alleviates Toll-like receptor (TLR)-associated chronic inflammation in fish, the underlying mechanism is not well understood.

OBJECTIVES

This study aimed to explore the role of Tlr22 in the innate immunity of large yellow croaker and investigate the anti-inflammatory effects of DHA on Tlr22-triggered inflammation.

METHODS

Head kidney-derived macrophages of croaker and HEK293T cells were or were not pretreated with 100 μM DHA for 10 h prior to polyinosinic-polycytidylic acid (poly I:C) stimulation. We executed qRT-PCR, immunoblotting, and lipidomic analysis to examine the impact of DHA on Tlr22-triggered inflammation and membrane lipid composition. In vivo, croakers (12.03 ± 0.05 g) were fed diets containing 0.2% [control (Ctrl)], 0.8%, and 1.6% DHA for 8 wk before injection with poly I:C. Inflammatory genes expression and rafts-related lipids and protein expression were measured in the head kidney. Data were analyzed by ANOVA or Student t test.

RESULTS

The activation of Tlr22 by poly I:C induced inflammation, and DHA diminished Tlr22-targeted inflammatory gene expression by 56-73% (P ≤ 0.05). DHA reduced membrane sphingomyelin (SM) and SFA-containing phosphatidylcholine (SFA-PC) contents, as well as lipid raft marker caveolin 1 amounts. Furthermore, lipid raft disruption suppressed Tlr22-induced Nf-κb and interferon h activation and p65 nuclear translocation. In vivo, expression of Tlr22 target inflammatory genes was 32-64% lower in the 1.6% DHA group than in the Ctrl group upon poly I:C injection (P ≤ 0.05). Also, the 1.6% DHA group showed a reduction in membrane SM and SFA-PC contents, accompanied by a decrease in caveolin 1 amounts, compared with the Ctrl group.

CONCLUSIONS

The activation of Tlr22 signaling depends on lipid rafts, and DHA ameliorates the Tlr22-triggered inflammation in both head kidney and head kidney-derived macrophages of croaker partially by altering membrane SMs and SFA-PCs that are required for lipid raft organization.

Acne, Microbiome, and Probiotics: The Gut–Skin Axis

The objective of this narrative review was to check the influence of the human microbiota in the pathogenesis of acne and how the treatment with probiotics as adjuvant or alternative therapy affects the evolution of acne vulgaris. Acne is a chronic inflammatory skin disease involving the pilosebaceous units. The pathogenesis of acne is complex and multifactorial involving genetic, metabolic, and hormonal factors in which both skin and gut microbiota are implicated. Numerous studies have shown the bidirectionality between the intestinal microbiota and skin homeostasis, a communication mainly established by modifying the immune system. Increased data on the mechanisms of action regarding the relevance of Cutibacterium acnes, as well as the importance of the gut–skin axis, are becoming known. Diverse and varied in vitro studies have shown the potential beneficial effects of probiotics in this context. Clinical trials with both topical and oral probiotics are scarce, although they have shown positive results, especially with oral probiotics through the modulation of the intestinal microbiota, generating an anti-inflammatory response and restoring intestinal integrity, or through metabolic pathways involving insulin-like growth factor I (IGF-1). Given the aggressiveness of some standard acne treatments, probiotics should continue to be investigated as an alternative or adjuvant therapy.

Understanding the role of host metabolites in the induction of immune senescence: Future strategies for keeping the ageing population healthy

Advancing age is accompanied by significant remodelling of the immune system, termed immune senescence, and increased systemic inflammation, termed inflammageing, both of which contribute towards an increased risk of developing chronic diseases in old age. Age-associated alterations in metabolic homeostasis have been linked with changes in a range of physiological functions, but their effects on immune senescence remains poorly understood. In this article, we review the recent literature to formulate hypotheses as to how an age-associated dysfunctional metabolism, driven by an accumulation of key host metabolites (saturated fatty acids, cholesterol, ceramides and lactate) and loss of other metabolites (glutamine, tryptophan and short-chain fatty acids), might play a role in driving immune senescence and inflammageing, ultimately leading to diseases of old age. We also highlight the potential use of metabolic immunotherapeutic strategies targeting these processes in counteracting immune senescence and restoring immune homeostasis in older adults. LINKED ARTICLES: This article is part of a themed issue on Inflammation, Repair and Ageing. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.9/issuetoc.

Comparative Proteomic Analysis of Membrane Vesicles from Clinical C. acnes Isolates with Differential Antibiotic Resistance

Purpose

Cutibacterium acnes (C. acnes) is closely associated with the pathogenesis of acne, and antibiotics targeting C. acnes have been widely used for decades. However, antibiotic resistance has been increasing rapidly. Membrane vesicles (MVs) have been found to play important roles in antibiotic resistance in some bacteria. We aimed to explore the mechanism of antibiotic resistance and the virulence components within C. acnes-derived MVs.

Materials and Methods

We isolated clinical C. acnes strains from the lesions of acne patients who were sensitive or resistant to the antibiotics erythromycin and clindamycin. We analyzed the proteome of MVs from four sensitive C. acnes isolates and three resistant isolates by LC-MS/MS.

Results

We identified 543 proteins within the MVs of clinical C. acnes strains. Several lipases, NlpC/P60, CAMP factor, and Hta domain protein were detected as virulence factors in the C. acnes-derived MVs. The levels of two lipases and FtsZ were significantly higher in resistant C. acnes-derived MVs compared with sensitive strains (p < 0.05).

Conclusion

According to the implications of this study, improper antibiotic use might not only increase antibiotic resistance in C. acnes but could also further alter the cutaneous lipid composition and aggravate host inflammation, thus resulting in worse clinical manifestations in acne patients. This study re-emphasizes that the improper use of antibiotics should be treated more seriously in clinical practice. Furthermore, to combat multidrug resistance in C. acnes, this study suggests that FtsZ inhibitors could be useful.

Chronic Inflammation in Obesity and Cancer Cachexia

Chronic inflammation has long been linked to obesity and related conditions such as type 2 diabetes and metabolic syndrome. According to current research, the increased risk of cancer in people with certain metabolic diseases may be due to chronic inflammation. Adipocytokines, which are pro-inflammatory cytokines secreted in excess, are elevated in many chronic metabolic diseases. Cytokines and inflammatory mediators, which are not directly linked to DNA, are important in tumorigenesis. Cachexia, a type of metabolic syndrome linked to the disease, is associated with a dysregulation of metabolic pathways. Obesity and cachexia have distinct metabolic characteristics, such as insulin resistance, increased lipolysis, elevated free fatty acids (FFA), and ceramide levels, which are discussed in this section. The goal of this research project is to create a framework for bringing together our knowledge of inflammation-mediated insulin resistance.

Dietary obesity and glycemic excursions cause a parallel increase in STEAP4 and pro-inflammatory gene expression in murine PBMCs

BACKGROUND

The balance between pro-atherogenic and anti-atherogenic factors is very crucial in the development of atherosclerotic lesions. Although the expression of the six-transmembrane epithelial antigen of the prostate 4 (STEAP4) in myeloid cells is known to be atheroprotective, there is not a single study reporting on the status of STEAP4 expression in circulating monocytes in the early stages of diet-induced obesity or in events of glycemic excursions.

METHODS

We induced glycemic spikes twice daily for a 1-week duration to rats fed on regular chow and western diet, and analyzed gene expression changes in the peripheral blood mononuclear cells (PBMCs). We also conducted experiments on RAW 264.7 cells to gain insight into some of our in vivo findings.

RESULTS

Diet-induced obesity and glycemic excursions independently caused a significant increase in STEAP4 mRNA expression in PBMCs. This was also accompanied by an induction of a substantial number of pro-inflammatory cytokines, chemokines, and chemokine receptors. However, the combined effect of western diet and hyperglycemic spikes was subtle and non-additive. In the in vitro setting, either glucose spikes, persistent hyperglycemia, or a combination of palmitic acid and insulin resulted in a parallel increase in expression of STEAP4 and pro-inflammatory genes. This was, however, significantly abrogated with 4-octyl itaconate or attenuated by inhibitors of p38MAPK and NF-kB.

CONCLUSIONS

STEAP4 expression in mononuclear cells is induced by increasing inflammation or oxidative stress. The observed increase in STEAP4 expression in circulating monocytes due to visceral obesity or glycemic excursions is a compensatory response.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13340-021-00542-1.

Dietary fatty acid patterns and risk of oesophageal squamous cell carcinoma

Background

To characterize and examine the associations between dietary fatty acid intake patterns and the risk of oesophageal squamous cell carcinoma (ESCC).

Methods

A total of 422 patients and 423 controls were recruited. Dietary fatty acids were entered into a factor analysis. Multivariable logistic regression and restricted cubic spline were used to evaluate the risk of ESCC specific for different dietary fatty acid patterns (FAPs). A forest plot was applied to show the association between FAPs and ESCC risk after stratification by lifestyle exposure factors (tobacco smoking, alcohol drinking, pickled food, fried food, hot food, hard food).

Results

The factor analysis generated four major fatty acid patterns: a medium- and long-chain SFA (MLC-SFA) pattern; an even-chain unsaturated fatty acid (EC-UFA) pattern, a saturated fatty acid (SFA) pattern and an n-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA) pattern. In the multivariate-adjusted model, the odds ratios (ORs) with 95% confidence intervals (CIs) of ESCC were 2.07 (1.31, 3.26) and 0.53 (0.34, 0.81) for the highest versus the lowest tertiles of the EC-UFA pattern and n-3 LC-PUFA pattern, respectively. The MLC-SFA and SFA patterns were not associated with ESCC. An association between FAPs and ESCC risk after stratification by lifestyle exposure factors was also observed.

Conclusions

Our study indicates that the EC-UFA pattern and n-3 LC-PUFA pattern intake are associated with ESCC, providing a potential dietary intervention for ESCC prevention.

Molecular Mechanism of Lipotoxicity as an Interesting Aspect in the Development of Pathological States-Current View of Knowledge

Free fatty acids (FFAs) play numerous vital roles in the organism, such as contribution to energy generation and reserve, serving as an essential component of the cell membrane, or as ligands for nuclear receptors. However, the disturbance in fatty acid homeostasis, such as inefficient metabolism or intensified release from the site of storage, may result in increased serum FFA levels and eventually result in ectopic fat deposition, which is unfavorable for the organism. The cells are adjusted for the accumulation of FFA to a limited extent and so prolonged exposure to elevated FFA levels results in deleterious effects referred to as lipotoxicity. Lipotoxicity contributes to the development of diseases such as insulin resistance, diabetes, cardiovascular diseases, metabolic syndrome, and inflammation. The nonobvious organs recognized as the main lipotoxic goal of action are the pancreas, liver, skeletal muscles, cardiac muscle, and kidneys. However, lipotoxic effects to a significant extent are not organ-specific but affect fundamental cellular processes occurring in most cells. Therefore, the wider perception of cellular lipotoxic mechanisms and their interrelation may be beneficial for a better understanding of various diseases’ pathogenesis and seeking new pharmacological treatment approaches.