The Potential of Molecular Docking for Predictive Toxicology.

Molecular modeling techniques are widely used in medicinal chemistry for the study of biological targets, the rational design of new drugs, or the investigation of their mechanism of action.They are also applied in toxicology to identify chemical potential harmful effects.Molecular docking is a computational technique to predict the ligand binding mode and evaluate the interaction energy with a biological target.This chapter describes a computational workflow to predict possible endocrine disruptors on peroxisome proliferator-activated receptor alpha (PPARα), a nuclear receptor involved in glucose and lipid metabolism. The analyzed compounds are food contact chemicals, natural or synthetic substances intentionally added to food or released from the package or during production or technological processes.

Fibroblast growth factor 21 attenuates pulmonary ischemia/reperfusion injury via inhibiting endoplasmic reticulum stress-induced ferroptosis though FGFR1/PPARδ signaling pathway.

BACKGROUND: Acute lung injury is a critical life-threatening complication of pulmonary and cardiac surgery with a high rate of morbidity and mortality. Fibroblast growth factor 21 (FGF21) has been reported to play an important role in protecting vital organs from damage. This study aims to investigate the potential protective role and mechanism of FGF21 in pulmonary ischemia/reperfusion (I/R)-induced acute lung injury. METHODS: A pulmonary epithelial cell line was treated with hypoxia/regeneration (H/R) in vitro and a mouse model of acute lung injury was induced with pulmonary I/R in vivo. Lung injury after pulmonary I/R was compared between FGF21-konckout (KO) mice and wild-type (WT) mice. Recombinant FGF21 was administrated in vivo and in vitro to determine its therapeutic effect. RESULTS: Circulating levels of FGF21 in mice with pulmonary I/R injury were significantly higher than in those without pulmonary I/R injury. Lung injury was aggravated in FGF21-KO mice compared with WT mice and the administration of FGF21 alleviated lung injury in mouse treated with I/R and pulmonary epithelial cell injury treated with H/R. FGF21 treatment decreased endoplasmic reticulum (ER) stress, Fe2+ and lipid reactive oxygen species (ROS) contents and GPX4 expression and increased PTGS2 levels. Mechanistically, FGF21 upregulated the expression of FGFR1 and PPARδ, ameliorated ER stress and ER stress induced-ferroptosis. Furthermore, FGF21 increased the expression level of PPARδ in pulmonary epithelial cell exposed to H/R, which was inhibited by FGFR1 inhibitor (PD173074). The protective effects of FGF21 were abolished by co-treatment with PPARδ inhibitor (GSK0660), indicating FGF21 attenuated ER stress-induced ferroptosis by dependent on FGFR1/PPARδ signaling pathway. CONCLUSION: Our study reveals that FGF21 protects against pulmonary I/R injury via inhibiting ER stress-induced ferroptosis though FGFR1/PPARδ signaling pathway. Boosting endogenous FGF21 or the administration of recombinant FGF21 could be promising therapeutic strategies for pulmonary IRI.

Isoliquiritigenin mitigates intervertebral disc degeneration induced by oxidative stress and mitochondrial impairment through a PPARγ-dependent pathway.

OBJECTIVES: Oxidative stress, mitochondrial dysfunction, and apoptosis play significant roles in the degradation of extracellular matrix (ECM) in nucleus pulposus cells (NPCs), ultimately contributing to intervertebral disc degeneration (IVDD). This study investigates the potential of isoliquiritigenin (ISL), a natural extract known for its antioxidant, anti-inflammatory, and anti-atherosclerotic properties, to alleviate IVDD. METHODS: The viability of NPCs treated with ISL and tert-butyl hydroperoxide (TBHP) was assessed using the CCK-8 assay. Various techniques, including Western blot, qRT-PCR, immunofluorescence (IF), and immunohistochemistry, were employed to measure the expression of ECM components, oxidative stress markers, and apoptosis-related proteins. Mitochondrial function was evaluated through Western blot and IF analyses. Network pharmacology predicted ISL targets, and the expression levels of PPARγ were assessed using the aforementioned methods. The role of PPARγ in the therapeutic effects of ISL on IVDD was examined through siRNA knockdown. The therapeutic impact of ISL on puncture-induced IVDD in rats was evaluated using X-ray, MRI, and histological staining techniques. RESULTS: In vitro, ISL reduced oxidative stress in NPCs, restored mitochondrial function, inhibited apoptosis, and improved the ECM phenotype. In vivo, ISL slowed the progression of IVDD in a rat model. Further analysis revealed that ISL enhances PPARγ activity and promotes its expression by direct binding, contributing to the delay of IVDD progression. CONCLUSION: This study demonstrates that ISL effectively treats puncture-induced IVDD in rats by inhibiting oxidative stress, restoring mitochondrial function, and reducing NPC apoptosis through a PPARγ-dependent mechanism. By balancing ECM synthesis and degradation, ISL presents a novel therapeutic approach for IVDD and identifies a promising target for treatment.

Comparative efficacy of THR-ß agonists, FGF-21 analogues, GLP-1R agonists, GLP-1-based polyagonists, and Pan-PPAR agonists for MASLD: A systematic review and network meta-analysis.

AIMS: To compare the efficacy of thyroid hormone receptor beta (THR-ß) agonists, fibroblast growth factor 21 (FGF-21) analogues, glucagon-like peptide-1 receptor agonists (GLP-1RAs), GLP-1-based polyagonists, and pan-peroxisome proliferator-activated receptor (Pan-PPAR) agonists in the treatment of metabolic dysfunction-associated steatotic liver disease (MASLD). METHODS: A database search for relevant randomized double-blind controlled trials published until July 11, 2024, was conducted. Primary outcomes were the relative change in hepatic fat fraction (HFF) and liver stiffness assessed non-invasively by magnetic resonance imaging proton density fat fraction and elastography. Secondary outcomes included histology, liver injury index, lipid profile, glucose metabolism, blood pressure, and body weight. RESULTS: Twenty-seven trials (5357 patients with MASLD) were identified. For HFF reduction, GLP-1-based polyagonists were most potentially effective (mean difference [MD] -51.47; 95 % confidence interval [CI]: -68.25 to -34.68; surface under the cumulative ranking curve [SUCRA] 84.9) vs. placebo, followed by FGF-21 analogues (MD -47.08; 95 % CI: -58.83 to -35.34; SUCRA 75.5), GLP-1R agonists (MD -37.36; 95 % CI: -69.52 to -5.21; SUCRA 52.3) and THR-ß agonists (MD -33.20; 95 % CI: -43.90 to -22.51; SUCRA 36.9). For liver stiffness, FGF-21 analogues were most potentially effective (MD -9.65; 95 % CI: -19.28 to -0.01; SUCRA 82.2) vs. placebo, followed by THR-ß agonists (MD -5.79; 95 % CI: -9.50 to -2.09; SUCRA 58.2), and GLP-1RAs (MD -5.58; 95 % CI: -15.02 to 3.86; SUCRA 54.7). For fibrosis improvement in histology, GLP-1-based polyagonists were most potentially effective, followed by FGF-21 analogues, THR-ß agonists, Pan-PPAR agonists, and GLP-1R agonists; For MASH resolution in histology, GLP-1-based polyagonists were most potentially effective, followed by THR-ß agonists, GLP-1R agonists, FGF-21 analogues, and Pan-PPAR agonists. THR-ß agonists are well-balanced in liver steatosis and fibrosis, and excel at improving lipid profiles; FGF-21 analogues are effective at improving steatosis and particularly exhibit strong antifibrotic abilities. GLP-1R agonists showed significant benefits in improving liver steatosis, glucose metabolism, and body weight. GLP-1-based polyagonists have demonstrated the most potential efficacy overall in terms of comprehensive curative effect. Pan-PPAR agonists showed distinct advantages in improving liver function and glucose metabolism. CONCLUSION: These results illustrate the relative superiority of the five classes of therapy in the treatment of MASLD and may serve as guidance for the development of combination therapies.

Scoparone alleviates nonalcoholic fatty liver disease by modulating the PPARα signaling pathway.

Scoparone (Scop), a natural compound derived from Artemisia capillaris Thunb, has demonstrated efficacy in improving nonalcoholic fatty liver disease (NAFLD). This study aims to explore the underlying mechanism. NAFLD was induced by a high-fat diet in C57BL/6J mice, followed by an 8-week treatment with Scop. The effect of Scop on mice NAFLD was assessed. mRNA sequencing of liver tissues was performed to identify potential targets, which were validated through in vitro experiments using palmitic acid-induced AML12 hepatocytes. The results demonstrated that Scop promoted lipid metabolism, insulin sensitivity, and liver function, and alleviated inflammation in NAFLD mice. mRNA sequencing identified the peroxisome proliferator-activated receptor α (PPARα) signaling pathway as a target of Scop, which was further confirmed by in vivo and in vitro experiments. Molecular docking studies showed that Scop could bind stably to human PPARα. In summary, Scop was proven to alleviate lipid metabolism dysfunction and inflammation by targeting the PPARα signaling pathway, which provides a basis for its potential application in NAFLD treatment.

Rifaximin alleviates MCD diet-induced NASH in mice by restoring the gut microbiota and intestinal barrier.

AIMS: Due to the increasing global incidence rate of nonalcoholic steatohepatitis (NASH) combined with the lack of effective treatment methods for this disease, there is an urgent need to find new treatment strategies. The aim of this study was to investigate the efficacy of rifaximin in preventing and treating NASH and the related mechanism. MATERIALS AND METHODS: A NASH model was constructed by feeding male C57BL/6 mice a methionine-choline-deficient (MCD) diet for 4 weeks. Rifaximin was administered for 1 week before MCD diet feeding or during the last week of MCD diet feeding to investigate its preventive or therapeutic effects. Liver pathology, hepatic enzyme levels and metabolic indices were measured to evaluate the effects of rifaximin on NASH. Intestinal barrier integrity was measured via the Ussing chamber system and western blotting. 16S rDNA sequencing was conducted to investigate the fecal microbiota composition. Western blotting was performed to evaluate peroxisome proliferator activated receptor (PPAR)α and PPARγ protein levels. KEY FINDINGS: Rifaximin effectively alleviated MCD diet-induced NASH. The microbiota composition in MCD diet-fed mice was significantly altered, and intestinal barrier integrity was disrupted. Dysbiosis and intestinal barrier dysfunction were reversed by rifaximin. In addition, rifaximin modulated PPARα and PPARγ expression in the liver. SIGNIFICANCE: Rifaximin effectively alleviated MCD diet-induced NASH by restoring the gut microbiota and reversing intestinal barrier dysfunction, suggesting that rifaximin treatment is a new approach for preventing and treating NASH.

FABP5+ lipid-loaded macrophages process tumor-derived unsaturated fatty acid signal to suppress T-cell antitumor immunity.

BACKGROUND & AIMS: Tumour-associated macrophages (TAMs) contribute to hepatocellular carcinoma (HCC) progression. However, while the pro-tumour and immunosuppressive roles of lipid-loaded macrophages are well established, the mechanisms by which lipid metabolism enhances the tumour-promoting effects in TAMs remain unclear. METHODS: Single-cell RNA sequencing was performed on mouse and human HCC tumour samples to elucidate the landscape of HCC TAMs. Macrophages were stimulated with various long-chain unsaturated fatty acids (UFAs) to assess immunosuppressive molecules expression in vitro. Additionally, in vivo and in vitro studies were conducted using mice with macrophage-specific deficiencies in fatty acid-binding protein 5 (FABP5) or peroxisome proliferator-activated receptor (PPAR). RESULTS: Single-cell RNA sequencing identified a subpopulation of FABP5+ lipid-loaded TAMs characterized by enhanced immune checkpoint blocker ligands and immunosuppressive molecules in an oncogene-mutant HCC mouse model and human HCC tumours. Mechanistically, long-chain UFAs released by tumour cells activate PPARvia FABP5, resulting in TAM immunosuppressive properties. FABP5 deficiency in macrophages decreases immunosuppressive molecules expression, enhances T-cell-dependent antitumor immunity, diminishes HCC growth, and improves immunotherapy efficacy. CONCLUSIONS: This study demonstrates that UFAs promote tumourigenesis by enhancing the immunosuppressive tumour microenvironment via FABP5-PPAR signaling and provides a proof-of-concept for targeting this pathway to improve tumour immunotherapy.

PPARγ-mediated amelioration of lipid metabolism abnormality by kaempferol.

Kaempferol can exert biological functions by regulating various signaling pathways. This study evaluated the ameliorative effect of kaempferol on lipid accumulation using oleic acid and palmitic acid-treated HepG2 cells and high-fat diet mice. In vitro oil red O staining showed that kaempferol treatment improved lipid accumulation (p < 0.001 for TG content and p < 0.05 for TC content). Immunofluorescence, western blot analysis and RT-qPCR showed that kaempferol could promote nuclear translocation of PPARγ and reduce the expression of PPARγ, C/EBPß, and SREBP-1c. Dietary intervention with kaempferol could reduce the lipid accumulation in hepatocytes and inflammatory cell infiltration, as well as attenuated serum levels of IL-6 and TNF-α in HFD-fed mice (p < 0.001 for IL-6 and p < 0.01 for TNF-α at kaempferol 60 mg/kg/d). Meanwhile, histopathological examination revealed that there was no substantial damage or distinct inflammation lesions in organs at the experimental dose, including the heart, lung, kidney, and spleen. The aforementioned research findings can serve as references for further preclinical investigations on the potential of kaempferol to mitigate lipid accumulation.

Revisiting PPAR agonists: novel perspectives in the treatment of primary biliary cholangitis.

INTRODUCTION: In primary biliary cholangitis (PBC), approximately 40% of the patients respond incompletely to first-line treatment with ursodeoxycholic acid (UDCA), resulting in a poorer prognosis. Although obeticholic acid (OCA) is approved as a second-line therapy, it is not well-tolerated by patients with significant itching or advanced cirrhosis. Peroxisome proliferator-activated receptor (PPAR) agonists, including fibrates traditionally known as antihyperlipidemic agents, have emerged as potent alternatives for treating PBC patients with an incomplete response to UDCA. AREAS COVERED: This article provides a detailed overview of the mechanisms of PPAR agonists and evaluates their efficacy and adverse events, focusing on findings from recent phase III clinical trials. EXPERT OPINION: PPAR agonists are significant alternatives in the treatment of PBC, showing the potential to enhance biochemical responses, reduce mortality, and alleviate pruritus. Long-term outcomes for PBC patients, particularly those with advanced disease, and longitudinal data on the antipruritic effects of PPAR agonists require further investigation. Combining PPAR agonists with other treatments and advancing personalized approaches may enhance therapeutic efficacy and patient outcomes. This study provides future perspectives on the roles of PPAR agonists in PBC management.

PPARγ drives mitochondrial stress signaling and the loss of atrial cardiomyocytes in newborn mice exposed to hyperoxia.

Diastolic dysfunction is increasingly common in preterm infants exposed to supplemental oxygen (hyperoxia). Previous studies in neonatal mice showed hyperoxia suppresses fatty acid synthesis genes required for proliferation and survival of atrial cardiomyocytes. The loss of atrial cardiomyocytes creates a hypoplastic left atrium that inappropriately fills the left ventricle during diastole. Here, we show that hyperoxia stimulates adenosine monophosphate-activated kinase (AMPK) and peroxisome proliferator activated receptor-gamma (PPARγ) signaling in atrial cardiomyocytes. While both pathways can regulate lipid homeostasis, PPARγ was the primary pathway by which hyperoxia inhibits fatty acid gene expression and inhibits proliferation of mouse atrial HL-1 cells. It also enhanced the toxicity of hyperoxia by increasing expression of activating transcription factor (ATF) 5 and other mitochondrial stress response genes. Silencing PPARγ signaling restored proliferation and survival of HL-1 cells as well as atrial cardiomyocytes in neonatal mice exposed to hyperoxia. Our findings reveal PPARγ enhances the toxicity of hyperoxia on atrial cardiomyocytes, thus suggesting inhibitors of PPARγ signaling may prevent diastolic dysfunction in preterm infants.

Team players in the pathogenesis of metabolic dysfunctions-associated steatotic liver disease: The basis of development of pharmacotherapy.

Nutrient metabolism is regulated by several factors. Social determinants of health with or without genetics are the primary regulator of metabolism, and an unhealthy lifestyle affects all modulators and mediators, leading to the adaptation and finally to the exhaustion of cellular functions. Hepatic steatosis is defined by presence of fat in more than 5% of hepatocytes. In hepatocytes, fat is stored as triglycerides in lipid droplet. Hepatic steatosis results from a combination of multiple intracellular processes. In a healthy individual nutrient metabolism is regulated at several steps. It ranges from the selection of nutrients in a grocery store to the last step of consumption of ATP as an energy or as a building block of a cell as structural component. Several hormones, peptides, and genes have been described that participate in nutrient metabolism. Several enzymes participate in each nutrient metabolism as described above from ingestion to generation of ATP. As of now several publications have revealed very intricate regulation of nutrient metabolism, where most of the regulatory factors are tied to each other bidirectionally, making it difficult to comprehend chronological sequence of events. Insulin hormone is the primary regulator of all nutrients' metabolism both in prandial and fasting states. Insulin exerts its effects directly and indirectly on enzymes involved in the three main cellular function processes; metabolic, inflammation and repair, and cell growth and regeneration. Final regulators that control the enzymatic functions through stimulation or suppression of a cell are nuclear receptors in especially farnesoid X receptor and peroxisome proliferator-activated receptor/RXR ligands, adiponectin, leptin, and adiponutrin. Insulin hormone has direct effect on these final modulators. Whereas blood glucose level, serum lipids, incretin hormones, bile acids in conjunction with microbiota are intermediary modulators which are controlled by lifestyle. The purpose of this review is to overview the key players in the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) that help us understand the disease natural course, risk stratification, role of lifestyle and pharmacotherapy in each individual patient with MASLD to achieve personalized care and target the practice of precision medicine. PubMed and Google Scholar databases were used to identify publication related to metabolism of carbohydrate and fat in states of health and disease states; MASLD, cardiovascular disease and cancer. More than 1000 publications including original research and review papers were reviewed.

Characterization of the C17.2 cell line as testing system for endocrine disruption-induced developmental neurotoxicity.

Hormone signaling plays an essential role during fetal life and is vital for brain development. Endocrine-disrupting chemicals can interfere with the hormonal milieu during this critical time-period, disrupting key neurodevelopmental processes. Hence, there is a need for the development of assays that evaluate developmental neurotoxicity (DNT) induced by an endocrine mode of action. Herein, we evaluated the applicability of the neural progenitor C17. 2 cell-line, as an in vitro test system to aid in the detection of endocrine disruption (ED) induced DNT. For this, C17.2 cells were exposed during 10 days of differentiation to agonists and antagonists of the thyroid hormone (Thr), glucocorticoid (Gr), retinoic acid (Rar), retinoic x (Rxr), oxysterols (Lxr), estrogen (Er), androgen (Ar), and peroxisome proliferator activated delta (Pparß/δ) receptors, as well as to the agonist of the vitamin D (Vdr) receptor. Upon exposure and differentiation, neuronal morphology (neurite outgrowth and branching), and the percentage of neurons in culture were assessed by immunofluorescence. For this, the cells were incubated with Hoechst (nuclear staining) and stained for ßIII-tubulin (neuronal marker). The C17.2 cells were responsive to the Rar, Rxr and Pparß/δ agonists which decreased neurite outgrowth and branching. Additionally, exposure to the Gr agonist increased the number of cells differentiating into neurons, while exposure to the Rxr agonist had the opposite effect. With this approach, we have identified that the C17.2 cells are responsive to Gr, Rar, Rxr, and Pparß/δ agonists, hence contributing to the development of test systems for hazard assessment of ED-induced DNT.

Endocrine disrupting chemicals (EDCs) interfere with hormonal signaling. As hormones play a vital role for an organism's development, EDC exposure is of high concern. In European regulations, the use of a chemical can be restricted if its toxicity is mediated by hormonal interference. A number of EDCs affect brain development. However, in animal tests, it is impossible to prove that a chemical induces developmental neurotoxicity (DNT) via endocrine disruption (ED). Furthermore, the regulatory DNT tests require large amounts of animals. Thus, there is an urgent need for in vitro test systems to identify ED-induced DNT. Herein we present the development of such a method based on the murine neural progenitor cell-line C17.2 with which neuronal differentiation processes can be mimicked. We show that differentiation of C17.2 cells are sensitive to retinoid, glucocorticoid, and peroxisome proliferator activated receptor signaling disruption, thus providing an alternative method for identifying ED-induced DNT.

Spatial Transcriptomic Study Reveals Heterogeneous Metabolic Adaptation and a Role of Pericentral PPARα/CAR/Ces2a Axis During Fasting in Mouse Liver.

Spatial heterogeneity and plasticity of the mammalian liver are critical for systemic metabolic homeostasis in response to fluctuating nutritional conditions. Here, a spatially resolved transcriptomic landscape of mouse livers across fed, fasted and refed states using spatial transcriptomics is generated. This approach elucidated dynamic temporal-spatial gene cascades and how liver zonation-both expression levels and patterns-adapts to shifts in nutritional status. Importantly, the pericentral nuclear receptor Nr1i3 (CAR) as a pivotal regulator of triglyceride metabolism is pinpointed. It is showed that the activation of CAR in the pericentral region is transcriptionally governed by Pparα. During fasting, CAR activation enhances lipolysis by upregulating carboxylesterase 2a, playing a crucial role in maintaining triglyceride homeostasis. These findings lay the foundation for future mechanistic studies of liver metabolic heterogeneity and plasticity in response to nutritional status changes, offering insights into the zonated pathology that emerge during liver disease progression linked to nutritional imbalances.

Lipid Storage, Lipolysis, and Lipotoxicity in Obesity.

The ratio of free fatty acid (FFA) turnover decreases significantly with the expansion of white adipose tissue. Adipose tissue and dietary saturated fatty acid levels significantly correlate with an increase in fat cell size and number. The G0/G1 switch gene 2 increases lipid content in adipocytes and promotes adipocyte hypertrophy through the restriction of triglyceride (triacylglycerol: TAG) turnover. Hypoxia in obese adipose tissue due to hypertrophic adipocytes results in excess deposition of extracellular matrix (ECM) components. Cluster of differentiation (CD) 44, as the main receptor of the extracellular matrix component regulates cell-cell and cell-matrix interactions including diet-induced insulin resistance. Excess TAGs, sterols, and sterol esters are surrounded by the phospholipid monolayer surface and form lipid droplets (LDs). Once LDs are formed, they grow up because of the excessive amount of intracellular FFA stored and reach a final size. The ratio of FFA turnover/lipolysis decreases significantly with increases in the degree of obesity. Dysfunctional adipose tissue is unable to expand further to store excess dietary lipids, increased fluxes of plasma FFAs lead to ectopic fatty acid deposition and lipotoxicity. Reduced neo-adipogenesis and dysfunctional lipid-overloaded adipocytes are hallmarks of hypertrophic obesity linked to insulin resistance. Obesity-associated adipocyte death exhibits feature of necrosis-like programmed cell death. Adipocyte death is a prerequisite for the transition from hypertrophic to hyperplastic obesity. Increased adipocyte number in obesity has life-long effects on white adipose tissue mass. The positive correlation between the adipose tissue volume and magnetic resonance imaging proton density fat fraction estimation is used for characterization of the obesity phenotype, as well as the risk stratification and selection of appropriate treatment strategies. In obese patients with type 2 diabetes, visceral adipocytes exposed to chronic/intermittent hyperglycemia develop a new microRNAs' (miRNAs') expression pattern. Visceral preadipocytes memorize the effect of hyperglycemia via changes in miRNAs' expression profile and contribute to the progression of diabetic phenotype. Nonsteroidal anti-inflammatory drugs, metformin, and statins can be beneficial in treating the local or systemic consequences of white adipose tissue inflammation. Rapamycin inhibits leptin-induced LD formation. Collectively, in this chapter, the concept of adipose tissue remodeling in response to adipocyte death or adipogenesis, and the complexity of LD interactions with the other cellular organelles are reviewed. Furthermore, clinical perspective of fat cell turnover in obesity is also debated.

Misalignment of Circadian Rhythms in Diet-Induced Obesity.

The biological clocks of the circadian timing system coordinate cellular and physiological processes and synchronize them with daily cycles. While the central clock in the suprachiasmatic nucleus (SCN) is mainly synchronized by the light/dark cycles, the peripheral clocks react to other stimuli, including the feeding/fasting state, nutrients, sleep-wake cycles, and physical activity. During the disruption of circadian rhythms due to genetic mutations or social and occupational obligations, incorrect arrangement between the internal clock system and environmental rhythms leads to the development of obesity. Desynchronization between the central and peripheral clocks by altered timing of food intake and diet composition leads to uncoupling of the peripheral clocks from the central pacemaker and to the development of metabolic disorders. The strong coupling of the SCN to the light-dark cycle creates a situation of misalignment when food is ingested during the "wrong" time of day. Food-anticipatory activity is mediated by a self-sustained circadian timing, and its principal component is a food-entrainable oscillator. Modifying the time of feeding alone greatly affects body weight, whereas ketogenic diet (KD) influences circadian biology, through the modulation of clock gene expression. Night-eating behavior is one of the causes of circadian disruption, and night eaters have compulsive and uncontrolled eating with severe obesity. By contrast, time-restricted eating (TRE) restores circadian rhythms through maintaining an appropriate daily rhythm of the eating-fasting cycle. The hypothalamus has a crucial role in the regulation of energy balance rather than food intake. While circadian locomotor output cycles kaput (CLOCK) expression levels increase with high-fat diet-induced obesity, peroxisome proliferator-activated receptor-alpha (PPARα) increases the transcriptional level of brain and muscle aryl hydrocarbon receptor nuclear translocator (ARNT)-like 1 (BMAL1) in obese subjects. In this context, effective timing of chronotherapies aiming to correct SCN-driven rhythms depends on an accurate assessment of the SCN phase. In fact, in a multi-oscillator system, local rhythmicity and its disruption reflects the disruption of either local clocks or central clocks, thus imposing rhythmicity on those local tissues, whereas misalignment of peripheral oscillators is due to exosome-based intercellular communication.Consequently, disruption of clock genes results in dyslipidemia, insulin resistance, and obesity, while light exposure during the daytime, food intake during the daytime, and sleeping during the biological night promote circadian alignment between the central and peripheral clocks. Thus, shift work is associated with an increased risk of obesity, diabetes, and cardiovascular diseases because of unusual eating times as well as unusual light exposure and disruption of the circadian rhythm.

MicroRNAs as Epigenetic Regulators of Obesity.

In obesity, the process of adipogenesis largely determines the number of adipocytes in body fat depots. Adipogenesis is regulated by several adipocyte-selective micro-ribonucleic acids (miRNAs) and transcription factors that modulate adipocyte proliferation and differentiation. However, some miRNAs block the expression of master regulators of adipogenesis. Since the specific miRNAs display different expressions during adipogenesis, in mature adipocytes and permanent obesity, their use as biomarkers or therapeutic targets is feasible. Upregulated miRNAs in persistent obesity are downregulated during adipogenesis. Moreover, some of the downregulated miRNAs in obese individuals are upregulated in mature adipocytes. Induction of adipocyte stress and hypertrophy leads to the release of adipocyte-derived exosomes (AdEXs) that contain the cargo molecules, miRNAs. miRNAs are important messengers for intercellular communication involved in metabolic responses and have very specific signatures that direct the metabolic activity of target cells. While each miRNA targets multiple messenger RNAs (mRNAs), which may coordinate or antagonize each other's functions, several miRNAs are dysregulated in other tissues during obesity-related comorbidities. Deletion of the miRNA-processing enzyme DICER in pro-opiomelanocortin-expressing cells results in obesity, which is characterized by hyperphagia, increased adiposity, hyperleptinemia, defective glucose metabolism, and alterations in the pituitary-adrenal axis. In recent years, RNA-based therapeutical approaches have entered clinical trials as novel therapies against overweight and its complications. Development of lipid droplets, macrophage accumulation, macrophage polarization, tumor necrosis factor receptor-associated factor 6 activity, lipolysis, lipotoxicity, and insulin resistance are effectively controlled by miRNAs. Thereby, miRNAs as epigenetic regulators are used to determine the new gene transcripts and therapeutic targets.

Inter-Organ Communication Involved in Brown Adipose Tissue Thermogenesis.

Brown and beige adipocytes produce heat from substrates such as fatty acids and glucose. Such heat productions occur in response to various stimuli and are called adaptive non-shivering thermogenesis. This review introduces mechanisms known to regulate brown and beige adipocyte thermogenesis. Leptin and fibroblast growth factor 21 (FGF21) are examples of periphery-derived humoral factors that act on the central nervous system (CNS) and increase brown adipose tissue (BAT) thermogenesis. Additionally, neuronal signals such as those induced by intestinal cholecystokinin and hepatic peroxisome proliferator-activated receptor γ travel through vagal afferent-CNS-sympathetic efferent-BAT pathways and increase BAT thermogenesis. By contrast, some periphery-derived humoral factors (ghrelin, adiponectin, plasminogen activator inhibitor-1, and soluble leptin receptor) act also on CNS but inhibit BAT thermogenesis. Neuronal signals also reduce BAT sympathetic activities and BAT thermogenesis, one such example being signals derived by hepatic glucokinase activation. Beige adipocytes can be induced by myokines (interleukin 6, irisin, and ß-aminoisobutyric acid), hepatokines (FGF21), and cardiac-secreted factors (brain natriuretic peptide). Cold temperature and leptin also stimulate beige adipocytes via sympathetic activation. Further investigation on inter-organ communication involving adipocyte thermogenesis may lead to the elucidation of how body temperature is regulated and, moreover, to the development of novel strategies to treat metabolic disorders.

Effects of a Muscle Relaxation Technique on Catatonia Symptoms Associated With Schizophrenia: A Case Report.

Catatonia is characterized by the loss of voluntary control over the workings of the mind and body. It disrupts daily life by manifesting as idle posture, heightened muscle tone, and repetitive purposeless movements. However, specific physiotherapy methods addressing these symptoms are yet to be established. This case report describes a 63-year-old man hospitalized for schizophrenia who was then diagnosed with stuporous catatonia based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) criteria, characterized by catalepsy, mutism, and difficulty performing daily activities. This case report aimed to evaluate the effectiveness of a specific muscle relaxation technique, squeeze-hold (SH), in treating catatonia associated with schizophrenia and its impact on daily activities. The patient exhibited catalepsy, mutism, and difficulty in performing daily activities. The SH technique employed temporarily obstructs muscle blood flow to induce ischemia, resulting in the relaxation of vascular smooth muscle due to CO2 retention. Furthermore, shear stress upon reperfusion stimulates nitric oxide production in the vascular endothelium, enhancing blood flow. Following weekly SH on the bilateral thighs, the muscle tone in the lower extremities was alleviated within two weeks, and the patient no longer required a wheelchair by the eighth week. In addition, responsiveness to verbal commands improved. As muscle tone in the lower limbs improved, the patient regained ambulation, and his improved responsiveness facilitated independent eating during activities of daily living (ADLs), potentially enhancing motivation and spontaneity. These findings suggest that muscle tone relaxation due to enhanced blood flow and increased CO2 concentration from blood flow restriction may have promoted ß-endorphin secretion, thereby improving symptoms via brain-derived neurotrophic factor expression through PGC-1α activation. In conclusion, the SH muscle relaxation technique effectively alleviated catatonic symptoms, and improved muscle tone and daily functioning in patients with schizophrenia-associated catatonia. These findings suggest that this physiotherapy approach may be a valuable addition to catatonia treatment, potentially contributing to physical and psychiatric rehabilitation. This case report illustrates the efficacy of a muscle-tone-focused treatment approach in physical therapy for catatonia and posits its contribution to the reacquisition of psychiatric function and ADLs.

Tofogliflozin attenuates renal lipid deposition and inflammation via PPARα upregulation mediated by miR-21a impairment in diet-induced steatohepatitic mice.

We previously demonstrated hepatic, cardiac, and skin inflammation in a high-fat diet-induced steatotic liver disease (SLD) model. However, the molecular mechanism in the kidneys in this model remains unclear. It has been recently reported that SGLT2 inhibitors improve chronic kidney disease (CKD). Therefore, we used this model to evaluate the effects of tofogliflozin on renal lipid metabolism and inflammation. Male 8-10-week-old C57Bl/6 mice were fed a high-fat/high-cholesterol/high-sucrose/bile acid (HF/HC/HS/BA) diet with 0.015% tofogliflozin (Tofo group) or an HF/HC/HS/BA diet alone (SLD group). After eight weeks, serum lipid profiles, histology, lipid content, and mRNA/microRNA and protein expression levels in the kidney were examined. The Tofo group showed significant reductions in body (26.9 ± 0.9 vs. 24.5 ± 1.0 g; p < 0.001) and kidney weight compared to those of the SLD group. Renal cholesterol (9.1 ± 1.6 vs. 7.5 ± 0.7 mg/g; p < 0.05) and non-esterified fatty acid (NEFA) (12.0 ± 3.0 vs. 8.4 ± 1.5 µEq/g; p < 0.01) were significantly decreased in the Tofo group. Transmission electron microscopy revealed the presence of fewer lipid droplets. mRNA sequencing analysis revealed that fatty acid metabolism-related genes were upregulated and NFκB signaling pathway-related genes were downregulated in the Tofo group. MicroRNA sequencing analysis indicated that miR-21a was downregulated and miR-204 was upregulated in the Tofo group. Notably, the expression of PPARα, which has been known to be negatively regulated by miR-21, was significantly increased, leading to enhancing ß-oxidation genes, Acox1 and Cpt1 in the Tofo group. Tofogliflozin decreased renal cholesterol and NEFA levels and improved inflammation through the regulation of PPARα and miR-21a.

Chronic glial activation and behavioral alterations induced by acute/subacute pioglitazone treatment in a mouse model of traumatic brain injury.

Traumatic brain injury (TBI) is a disabling neurotraumatic condition and the leading cause of injury-related deaths and disability in the United States. Attenuation of neuroinflammation early after TBI is considered an important treatment target; however, while these inflammatory responses can induce secondary brain injury, they are also involved in the repair of the nervous system. Pioglitazone, which activates peroxisome proliferator-activated receptor gamma, has been shown to decrease inflammation acutely after TBI, but the long-term consequences of its use remain unknown. For this reason, the impacts of treatment with pioglitazone during the acute/subacute phase (30 min after injury and each subsequent 24 h for 5 days) after TBI were interrogated during the chronic phase (30- and 274-days post-injury (DPI)) in mice using the controlled cortical impact model of experimental TBI. Acute/subacute pioglitazone treatment after TBI results in long-term deleterious consequences, including disruption of tau homeostasis, chronic glial cell activation, neuronal pathology, and worsened injury severity particularly at 274 DPI, with male mice being more susceptible than female mice. Further, male pioglitazone-treated TBI mice exhibited increased dominant and offensive-like behavior while having a decreased non-social exploring behavior at 274 DPI. After TBI, both sexes exhibited glial activation at 30 DPI when treated with pioglitazone; however, while injury severity was increased in females it was not impacted in male mice. This work reveals that although pioglitazone has been shown to lead to attenuated TBI outcomes acutely, sex-based differences, timing and long-term consequences of treatment with glitazones must be considered and further studied prior to their clinical use for TBI therapy.