Project description:Neuroinflammation, for which microglia are the predominant contributors, is a significant risk factor for cognitive dysfunction. Riboflavin (also known as vitamin B2) ameliorates cognitive impairment via anti-oxidative stress and anti-inflammation properties; however, the underlying mechanisms linking riboflavin metabolism and microglial function in cognitive impairment remain unclear. Here, it is demonstrated that riboflavin kinase (RFK), a critical enzyme in riboflavin metabolism, is specifically expressed in microglia. An intermediate product of riboflavin, flavin mononucleotide (FMN), inhibited RFK expression via regulation of lysine-specific methyltransferase 2B (KMT2B). FMN supplementation attenuated the pro-inflammatory TNFR1/NF-κB signaling pathway, and this effect is abolished by KMT2B overexpression. To improve the limited anti-inflammatory efficiency of free FMN, a biomimetic microglial nanoparticle strategy (designated as MNPs@FMN) is established, which penetrated the blood brain barrier with enhanced microglial-targeted delivery efficiency. Notably, MNPs@FMN ameliorated cognitive impairment and dysfunctional synaptic plasticity in a lipopolysaccharide-induced inflammatory mouse model and in a 5xFAD mouse model of Alzheimer's disease. Taken together, biomimetic microglial delivery of FMN may serve as a potential therapeutic approach for inflammation-dependent cognitive decline.
Project description:ObjectiveNon-alcoholic fatty liver disease (NAFLD) covers a wide spectrum of liver pathology ranging from simple fatty liver to non-alcoholic steatohepatitis (NASH). Notably, immune cell-driven inflammation is a key mechanism in the transition from fatty liver to the more serious NASH. Although exercise training is effective in ameliorating obesity-related diseases, the underlying mechanisms of the beneficial effects of exercise remain unclear. It is unknown whether there is an optimal modality and intensity of exercise to treat NAFLD. The objective of this study was to determine whether high-intensity interval training (HIIT) or moderate-intensity continuous training (MIT) is more effective at ameliorating the progression of NASH.MethodsWild-type mice were fed a high-fat, high-carbohydrate (HFHC) diet for 6 weeks and left sedentary (SED) or assigned to either an MIT or HIIT regimen using treadmill running for an additional 16 weeks. MIT and HIIT groups were pair-fed to ensure that energy intake was similar between the exercise cohorts. To determine changes in whole-body metabolism, we performed insulin and glucose tolerance tests, indirect calorimetry, and magnetic resonance imaging. NASH progression was determined by triglyceride accumulation, expression of inflammatory genes, and histological assessment of fibrosis. Immune cell populations in the liver were characterized by cytometry by time-of-flight mass spectrometry, and progenitor populations within the bone marrow were assessed by flow cytometry. Finally, we analyzed the transcriptional profile of the liver by bulk RNA sequencing.ResultsCompared with SED mice, both HIIT and MIT suppressed weight gain, improved whole-body metabolic parameters, and ameliorated the progression of NASH by reducing hepatic triglyceride levels, inflammation, and fibrosis. However, HIIT was superior to MIT at reducing adiposity, improving whole-body glucose tolerance, and ameliorating liver steatosis, inflammation, and fibrosis, without any changes in body weight. Improved NASH progression in HIIT mice was accompanied by a substantial decrease in the frequency of pro-inflammatory infiltrating, monocyte-derived macrophages in the liver and reduced myeloid progenitor populations in the bone marrow. Notably, an acute bout of MIT or HIIT exercise had no effect on the intrahepatic and splenic immune cell populations. In addition, bulk mRNA sequencing of the entire liver tissue showed a pattern of gene expression confirming that HIIT was more effective than MIT in improving liver inflammation and lipid biosynthesis.ConclusionsOur data suggest that exercise lessens hepatic inflammation during NASH by reducing the accumulation of hepatic monocyte-derived inflammatory macrophages and bone marrow precursor cells. Our findings also indicate that HIIT is superior to MIT in ameliorating the disease in a dietary mouse model of NASH.
Project description:Obesity is considered a chronic inflammatory disease, the inflammatory factors, such as interleukin 6 (IL-6), monocyte chemoattractant protein 1 (MCP-1) and small inducible cytokine A5 (RANTES), are elevated in obese individuals. Pituitary adenylate cyclase-activating polypeptide (PACAP) suppresses anti-inflammatory cytokines and ameliorates glucose and lipid metabolism. Our previous study showed that Fas apoptosis inhibitory molecule (FAIM) is a new mediator of Akt2 signalling, increases the insulin signalling pathway and lipid metabolism. In this study, we found that PACAP promoted the expression of FAIM protein in a human hepatocyte cell line (L02). Overexpression of FAIM with lentivirus suppressed the expression of the inflammatory factor interleukin 6 (IL-6), monocyte chemoattractant protein 1 (MCP-1) and tumour necrosis factor alpha (TNF-?). Following treatment of obese mice with FAIM or PACAP for 2 weeks, inflammation was alleviated and the bodyweight and blood glucose levels were decreased. Overexpression of FAIM down-regulated the expression of adipogenesis proteins, including SREBP1, SCD1, FAS, SREBP2 and HMGCR, and up-regulated glycogen synthesis proteins, including Akt2 (Ser474) phosphorylation, GLUT2 and GSK-3?, in the liver of obese mice. However, down-regulation of FAIM with shRNA promotes obesity. Altogether, our data identified that FAIM mediates the function of PACAP in anti-inflammation, glucose regulation and lipid metabolism in obese liver.
Project description:Rationale: Physical exercise is essential for skeletal integrity and bone health. The gut microbiome, as a pivotal modulator of overall physiologic states, is closely associated with skeletal homeostasis and bone metabolism. However, the potential role of intestinal microbiota in the exercise-mediated bone gain remains unclear. Methods: We conducted microbiota depletion and fecal microbiota transplantation (FMT) in ovariectomy (OVX) mice and aged mice to investigate whether the transfer of gut ecological traits could confer the exercise-induced bone protective effects. The study analyzed the gut microbiota and metabolic profiles via 16S rRNA gene sequencing and LC-MS untargeted metabolomics to identify key microbial communities and metabolites responsible for bone protection. Transcriptome sequencing and RNA interference were employed to explore the molecular mechanisms. Results: We found that gut microbiota depletion hindered the osteogenic benefits of exercise, and FMT from exercised osteoporotic mice effectively mitigated osteopenia. Comprehensive profiling of the microbiome and metabolome revealed that the exercise-matched FMT reshaped intestinal microecology and metabolic landscape. Notably, alterations in bile acid metabolism, specifically the enrichment of taurine and ursodeoxycholic acid, mediated the protective effects on bone mass. Mechanistically, FMT from exercised mice activated the apelin signaling pathway and restored the bone-fat balance in recipient MSCs. Conclusion: Our study underscored the important role of the microbiota-metabolic axis in the exercise-mediated bone gain, heralding a potential breakthrough in the treatment of osteoporosis.
Project description:IntroductionIn a recent screening to detect biomarkers in systemic lupus erythematosus (SLE), expression of the iron storage protein, ferritin, was increased. Given that proteins that regulate the storage, transfer and release of iron play an important role in inflammation, this study aims to determine the serum and urine levels of ferritin and of the iron transfer protein, transferrin, in lupus patients and to correlate these levels with disease activity, inflammatory cytokine levels and markers of anemia.MethodsA protein array was utilized to measure ferritin expression in the urine and serum of SLE patients and healthy controls. To confirm these results as well as the role of the iron transfer pathway in SLE, ELISAs were performed to measure ferritin and transferrin levels in inactive or active SLE patients and healthy controls. The relationship between ferritin/transferrin levels and inflammatory markers and anemia was next analyzed.ResultsProtein array results showed elevated ferritin levels in the serum and urine of lupus patients as compared to controls, which were further validated by ELISA. Increased ferritin levels correlated with measures of disease activity and anemia as well as inflammatory cytokine titers. Though active SLE patients had elevated urine transferrin, serum transferrin was reduced.ConclusionUrine ferritin and transferrin levels are elevated significantly in SLE patients and correlate with disease activity, bolstering previous reports. Most importantly, these changes correlated with the inflammatory state of the patients and anemia of chronic disease. Taken together, altered iron handling, inflammation and anemia of chronic disease constitute an ominous triad in SLE.
Project description:BackgroundAnemia occurring as a result of inflammatory processes (anemia of inflammation, AI) has a high prevalence in critically ill patients. Knowledge on changes in iron metabolism during the course of AI is limited, hampering the development of strategies to counteract AI. This case control study aimed to investigate iron metabolism during the development of AI in critically ill patients.MethodsIron metabolism in 30 patients who developed AI during ICU stay was compared with 30 septic patients with a high Hb and 30 non-septic patients with a high Hb. Patients were matched on age and sex. Longitudinally collected plasma samples were analyzed for levels of parameters of iron metabolism. A linear mixed model was used to assess the predictive values of the parameters.ResultsIn patients with AI, levels of iron, transferrin and transferrin saturation showed an early decrease compared to controls with a high Hb, already prior to the development of anemia. Ferritin, hepcidin and IL-6 levels were increased in AI compared to controls. During AI development, erythroferrone decreased. Differences in iron metabolism between groups were not influenced by APACHE IV score.ConclusionsThe results show that in critically ill patients with AI, iron metabolism is already altered prior to the development of anemia. Levels of iron regulators in AI differ from septic controls with a high Hb, irrespective of disease severity. AI is characterized by high levels of hepcidin, ferritin and IL-6 and low levels of iron, transferrin and erythroferrone.
Project description:Introduction Wenzi Jiedu Recipe (WJR), traditional Chinese medicine (TCM) formula, has been proven to be clinically useful in the treatment of colorectal cancer (CRC). However, its underlying mechanisms are still elusive, which limits its wider application. Thus, we aimed to evaluate the effect of WJR on CRC and elucidate mechanisms underlying its action. Methods Network pharmacology was employed to clarify the “herb-active ingredient-target” network of WJR. The 16S rDNA sequencing method was used to analyze the changes of gut microbes mediated by WJR in tumor-bearing mice with CRC. The proportions of CD4+ T cell and CD8+ T cell were measured by flow cytometry. Levels of the cytokines interleukin (IL)-10, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α were assessed by immunohistochemistry and enzyme-linked immunosorbent assay (ELISA). Results WJR showed significant anti-CRC effects both in vitro and in vivo. Network pharmacology revealed that WJR exerts anti-CRC therapeutic effect on multiple targets and signaling pathways. Gut microbiota analysis revealed that WJR therapy significantly enriched for Oscillibacter and Bacteroides_acidifacien. In particular, we found that WJR significantly increased the proportion of CD8+ T cells and the expression of immune-associated cytokines IL-10, IFN-γ, and TNF-α. Conclusion The regulation of gut microbiota by WJR may be the breakthrough point to clarify its mechanism of action in the treatment of CRC, and it has a good prospect of clinical application.
Project description:Following cardiac injury, increased adrenergic drive plays an important role in compensating for reduced cardiac function. However, chronic excess adrenergic stimulation can be detrimental to cardiac pathophysiology and can also affect other organs including adipose tissue, leading to increased lipolysis. Interestingly, inhibition of adipose triglyceride lipase (ATGL), a rate-limiting enzyme in lipolysis, in adipocytes ameliorates cardiac dysfunction in a heart failure model. Thus, we investigated whether inhibition of adipocyte ATGL can mitigate the adverse cardiac effects of chronic adrenergic stimulation and explored the underlying mechanisms. To do this, isoproterenol (ISO) was continuously administered to C57Bl/6N mice for 2 wk with or without an ATGL inhibitor (Atglistatin). We found that Atglistatin alleviated ISO-induced cardiac remodeling and reduced ISO-induced upregulation of galectin-3, a marker of activated macrophages and a potent inducer of fibrosis, in white adipose tissue (WAT), heart, and the circulation. To test whether the beneficial effects of Atglistatin occur via inhibition of adipocyte ATGL, adipocyte-specific ATGL knockout (atATGL-KO) mice were utilized for similar experiments. Subsequently, the same cardioprotective effects of atATGL-KO following ISO administration were observed. Furthermore, Atglistatin and atATGL-KO abolished ISO-induced galectin-3 secretion from excised WAT. We further demonstrated that activation of cardiac fibroblasts by the conditioned media of ISO-stimulated WAT is galectin-3-dependent. In conclusion, the inhibition of adipocyte ATGL ameliorated ISO-induced cardiac remodeling possibly by reducing galectin-3 secretion from adipose tissue. Thus, inhibition of adipocyte ATGL might be a potential target to prevent some of the adverse effects of chronic excess adrenergic drive.NEW & NOTEWORTHY The reduction of lipolysis by adipocyte ATGL inhibition ameliorates cardiac remodeling induced by chronic β-adrenergic stimulation likely via reducing galectin-3 secretion from adipose tissue. Our findings highlight that suppressing lipolysis in adipocytes may be a potential therapeutic target for patients with heart failure whose sympathetic nervous system is activated. Furthermore, galectin-3 might be involved in the mechanisms by which excessive lipolysis in adipose tissues influences remote cardiac pathologies and thus warrants further investigation.
Project description:Leukotrienes are biologically active eicosanoid lipid mediators that originate from oxidative metabolism of arachidonic acid. Biosynthesis of leukotrienes involves a set of soluble and membrane-bound enzymes that constitute a machinery complex primarily expressed by cells of myeloid origin. Leukotrienes and their synthetic enzymes are critical immune modulators for leukocyte migration. Increased concentrations of leukotrienes are implicated in a number of inflammatory disorders. More recent work indicates that leukotrienes may also interact with a variety of tissue cells, contributing to the low-grade inflammation of cardiovascular, neurodegenerative, and metabolic conditions, as well as that of cancer. Leukotriene signaling contributes to the active tumor microenvironment, promoting tumor growth and resistance to immunotherapy. This review summarizes recent insights into the intricate roles of leukotrienes in promoting tumor growth and metastasis through shaping the tumor microenvironment. The emerging possibilities for pharmacological targeting of leukotriene signaling in tumor metastasis are considered.
Project description:Triple-negative breast cancer (TNBC) stands out for its aggressiveness and accelerated rate of proliferation. Evidence shows that exercise may exert antitumorigenic effects, but the biochemical mechanisms underlying them remain unclear. Our objective was to evaluate the ability of exercise to modulate tumor growth and energy metabolism in an experimental TNBC model. Female BALB/c mice were sedentary or trained for 12 weeks and inoculated with 1 × 104 4T1 cells in the eighth week. Analyzes of macronutrient oxidation, mitochondrial respiration, and expression of genes related to cell metabolism were performed. The results showed that the trained group had a smaller tumor mass and the mitochondria in the tumors presented lower respiratory rates in the state of maximum electron transport capacity. Additionally, the tumors of the exercised group showed a higher expression of genes related to tumor suppressors, while the genes linked with cellular growth were similar between groups. Furthermore, the training modulated the corporal macronutrient oxidation to almost exclusive carbohydrate oxidation, while the sedentary condition metabolized both carbohydrate and lipids. Therefore, the exercise reduced tumor growth, with an impact on mitochondrial and macronutrient metabolism. Our results shed light on the understanding of the antitumorigenic effects of physical exercise, particularly regarding the metabolic transformations in TNBC.