Search Results (26)

Background/Objectives: The receptor for advanced glycation end products (RAGEs) has been implicated in obesity and metabolic dysfunction. However, its precise role in diet-induced obesity remains unclear. Methods: In this study, we investigated the metabolic consequences of RAGE knockout (RAGE KO) in mice subjected to a Western diet (WD). Results: Our findings demonstrate that RAGE KO mice remained significantly leaner than their wild-type (WT) counterparts when fed a WD, exhibiting reduced body weight gain and smaller adipocyte size. Indirect calorimetry revealed that RAGE KO mice had increased oxygen consumption and locomotor activity compared to WT mice, indicating enhanced energy expenditure. Mitochondrial respiration assays indicated significantly greater oxygen consumption in RAGE KO animals. Additionally, systemic inflammation markers, such as TNF-α, were significantly lower in RAGE KO mice when fed a WD, indicating a reduction in diet-induced inflammatory responses. Conclusions: These findings suggest that RAGE plays a key role in metabolic homeostasis, and its deletion confers resistance to obesity and metabolic disruption induced by a Western diet. Targeting RAGE may provide a novel therapeutic approach for combating obesity and related metabolic disorders. Full article

Apoptosis is critical in placental development, and its dysregulation is linked to pregnancy complications such as intrauterine growth restriction (IUGR) and preeclampsia (PE). Environmental exposures, particularly secondhand smoke (SHS) and e-cigarettes (eCigs), may contribute to placental dysfunction through apoptotic pathways. This study examined the effects of SHS and eCig exposure on placental apoptosis and growth-regulatory proteins in a murine model. C57BL/6 pregnant mice were exposed to SHS or eCigs at two critical gestational time points: early trophoblast invasion (E12.5 to E18.5) and established invasion (E14.5 to E18.5). Placental tissues were collected and analyzed for pro-apoptotic and anti-apoptotic markers, heat shock proteins, insulin-like growth factor-binding proteins (IGFBPs), and growth regulators. SHS exposure increased pro-apoptotic markers (BAD, Fas/FasL) and decreased mitochondrial function markers (cytochrome c), indicating compromised cellular survival. Both SHS and eCig exposure reduced anti-apoptotic markers (BCL-2, HSP27, survivin) and growth regulators (IGF-1, IGFBPs). SHS and eCig exposure create a pro-apoptotic environment in the placenta, potentially impairing fetal development through altered apoptotic and growth-regulatory pathways. These findings underscore the risks of environmental exposures during pregnancy, highlighting the need for strategies to minimize maternal exposure to SHS and eCigs. Full article

Gestational diabetes mellitus (GDM) affects placental metabolism, influencing both maternal and fetal outcomes. This study investigated the expression of metabolic regulators—Pyruvate Kinase M2 (PKM2), AMP-activated protein kinase (AMPK), and mTOR pathway components—in placental tissues from GDM pregnancies managed with either insulin (GDM-I) or dietary interventions (GDM-D). We hypothesize that metabolic adaptation in GDM is differentially regulated by treatment modality. This study analyzed 30 cases, including 10 control pregnancies,10 GDM-D cases, and 10 GDM-I cases. Analytical methods included immunofluorescence and immunoblotting. We observed an upregulation of PKM2 in both GDM-I and GDM-D placentas, suggesting enhanced glycolytic adaptation under GDM-induced metabolic stress. AMPK expression was significantly elevated in GDM-I and moderately increased in GDM-D placentas, potentially compensating for insulin resistance by promoting glucose uptake and energy homeostasis. Furthermore, mTOR pathway activation differed by treatment type, suggesting a treatment-specific mTOR response. The metabolic changes observed suggest that treatment modality in GDM may have direct implications for maternal and fetal health. Our findings indicate that while insulin and dietary management support metabolic adaptation in GDM, they do so through distinct mechanisms. These findings support a personalized approach in GDM treatment, where patient-specific metabolic responses should guide therapeutic decisions. Full article

Background/Objectives: The increasing prevalence of metabolic disorders underscores the need for effective interventions to mitigate environmental stressors such as diesel particulate matter (DPM), a major urban air pollutant. DPM is composed of fine carbonaceous particles that can induce systemic inflammation. This phenomenon results in metabolic dysfunction such as adipocyte hypertrophy, insulin resistance, and mitochondrial impairment in body tissues. Methods: This study investigated the impact of DPM exposure on murine lung, skeletal muscle, and adipose tissues and evaluated the protective effects of supplementation with sodium copper chlorophyllin (SCC). Results: Compared to controls, DPM-exposed mice exhibited significantly elevated oxidative stress markers (* p ≤ 0.05), systemic pro-inflammatory cytokines including TNF-α, MCP-1, IL-6, and IL-1β (* p ≤ 0.05), and adipocyte hypertrophy of both subcutaneous and visceral fat depots, supporting prior findings of DPM-induced metabolic dysfunction. SCC supplementation restored pulmonary ATP levels (* p ≤ 0.05), significantly reduced ROS production in lung and muscle tissue (* p ≤ 0.05), and significantly attenuated DPM-induced inflammatory cytokine secretion (* p ≤ 0.05), while lessening DPM-induced adipocyte hypertrophy. Conclusions: These effects highlight the antioxidant and anti-inflammatory potential of SCC, which likely mitigates systemic metabolic compromise by modulating mitochondrial function and inflammatory pathways. This study further demonstrated that SCC supplementation may be an effective intervention for alleviating the adverse effects of DPM exposure on metabolic and inflammatory compromise. Additional research may clarify a role for SCC in reducing systemic health risks associated with air pollution and offer a foundation for future translational research in human populations exposed to environmental pollutants. Full article

Preeclampsia (PE) is a complex pregnancy-specific disorder characterized by hypertension, proteinuria, and systemic inflammation, posing significant risks to maternal and fetal health. This study investigates the role of growth arrest-specific protein 6 (Gas6) in PE pathogenesis using a rat model. Gas6 administration induces hallmark PE features, including hypertension, proteinuria, and significant alterations in placental gene expression. Transcriptomic analysis revealed changes in pathways related to extracellular matrix remodeling, interleukin signaling, and oxidative stress, highlighting their contribution to PE pathology. Key findings include the upregulation of Fam111a, linked to oxidative stress and DNA replication, and the downregulation of Clca4, associated with ion transport and cellular homeostasis. Protein-level validation through immunofluorescence confirmed these alterations, reinforcing their mechanistic roles in placental dysfunction. Enrichment analysis further identified significant disruptions in extracellular matrix organization and intercellular signaling. These results underscore the pivotal role of Gas6 in exacerbating placental oxidative stress and systemic inflammation. Importantly, therapeutic inhibition of the Gas6/AXL axis using small-molecule inhibitors mitigated PE-like symptoms, highlighting its potential as a therapeutic target. This study provides novel insights into the molecular underpinnings of Gas6-mediated placental dysfunction and supports the development of targeted therapies to improve PE outcomes. Full article

Background/Objectives: Yerba maté (YM), a traditional herbal beverage made from Ilex paraguariensis, contains bioactive compounds like polyphenols and alkaloids known for their metabolic benefits. This study investigates YM’s incretin effects, focusing on glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP). Methods: Male and female C57BL/6 mice were supplemented with YM for four weeks. Post-supplementation, GLP-1 and GIP gene expression levels were analyzed in jejunal mucosa, and plasma hormone concentrations were measured. Additionally, in vitro experiments were conducted using GLUTag L-cells to evaluate the direct effects of YM and its metabolites, including ferulic acid and dihydroferulic acid, on GLP-1 secretion. Gene expression analysis involved quantitative real-time PCR, while hormone levels were assessed via ELISA. Results: YM supplementation significantly increased GLP-1 gene expression and plasma GLP-1 levels compared to controls, with no changes observed in GIP expression or plasma levels. Direct treatment of GLUTag L-cells with YM did not enhance GLP-1 secretion. However, dihydroferulic acid, a microbial metabolite of ferulic acid, markedly stimulated GLP-1 production in L-cells, highlighting a role of gut-mediated metabolism in YM’s incretin effects. Conclusions: YM selectively upregulates GLP-1 pathways without affecting GIP, likely through gut-mediated mechanisms. These findings suggest YM as a promising nutraceutical for incretin modulation and metabolic disorder management. Further studies should explore the interplay between YM, the gut microbiota, and incretin pathways to fully realize its therapeutic potential. Full article

Receptors for advanced glycation end products (RAGE) are multiligand cell surface receptors found most abundantly in lung tissue. This study sought to evaluate the role of RAGE in lung development by using a transgenic (TG) mouse model that spatially and temporally controlled RAGE overexpression. Histological imaging revealed that RAGE upregulation from embryonic day (E) 15.5 to E18.5 led to a thickened alveolar parenchyma and reduced alveolar surface area, while RAGE overexpression from E0 to E18.5 caused a significant loss of tissue and decreased architecture. Mitochondrial dysfunction was a hallmark of RAGE-mediated disruption, with decreased levels of anti-apoptotic BCL-W and elevated pro-apoptotic BID, SMAC, and HTRA2, indicating compromised mitochondrial integrity and increased intrinsic apoptotic activity. Extrinsic apoptotic signaling was similarly dysregulated, as evidenced by the increased expression of TNFRSF21, Fas/FasL, and Trail R2 in E0-18.5 RAGE TG mice. Additionally, reductions in IGFBP-3 and IGFBP-4, coupled with elevated p53 and decreased p27 expression, highlighted disruptions in the cell survival and cycle regulatory pathways. Despite the compensatory upregulation of inhibitors of apoptosis proteins (cIAP-2, XIAP, and Survivin), tissue loss and structural damage persisted. These findings underscore RAGE’s role as a pivotal modulator of lung development. Specifically, the timing of RAGE upregulation significantly impacts lung development by influencing pathways that cause distinct histological phenotypes. This research may foreshadow how RAGE signaling plausibly contributes to developmental lung diseases. Full article

Background: Uric acid (UA), a metabolite of purine and fructose metabolism, is linked to inflammation and metabolic disorders, including gout and cardiovascular disease. Its pro-inflammatory effects are largely driven by the activation of the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, leading to increased cytokine production. Beta-hydroxybutyrate (BHB), a ketone produced during fasting or carbohydrate restriction, has been shown to reduce inflammation. This study explores the role of BHB in mitigating the inflammatory and metabolic effects of elevated uric acid levels. Methods: We utilized a murine muscle cell culture treated with UA and BHB. Results: Muscle cells treated with UA had increased production of pro-inflammatory cytokines and reduced cell viability. Co-treatment with BHB reversed these effects, improving cell survival and reducing cytokine levels. Additionally, uric acid impaired mitochondrial function and increased oxidative stress, which were mitigated by BHB. Furthermore, uric acid disrupted insulin signaling, but BHB co-treatment restored insulin sensitivity. Conclusions: These findings suggest that BHB holds therapeutic potential by counteracting the inflammatory and metabolic disruptions caused by elevated uric acid, making it a promising target for conditions such as hyperuricemia and metabolic syndrome. Full article

A complication of reducing sugars is that they can undergo Maillard chemical reactions, forming advanced glycation end-products (AGEs) that can induce oxidative stress and inflammation via engagements with the main receptor for AGEs (RAGE) in various tissues. Certain sugars, such as glucose and fructose, are well known to cause AGE formation. Recently, allulose has emerged as a rare natural sugar that is an epimer of fructose and which is of low caloric content that is minimally metabolized, leading to it being introduced as a low-calorie sugar alternative. However, the relative ability of allulose to generate AGEs compared to glucose and fructose is not known. Here we assess the accumulation of AGEs in cell-free, in vitro, and in vivo conditions in response to allulose and compare it to glycation mediated by glucose or fructose. AGEs were quantified in cell-free samples, cell culture media and lysates, and rat serum with glycation-specific ELISAs. In cell-free conditions, we observed concentration and time-dependent increases in AGEs when bovine serum albumin (BSA) was incubated with glucose or fructose and significantly less glycation when incubated with allulose. AGEs were significantly elevated when pulmonary alveolar type II-like cells were co-incubated with glucose or fructose; however, significantly less AGEs were detected when cells were exposed to allulose. AGE quantification in serum obtained from rats fed a high-fat, low-carb (HFLC) Western diet for 2 weeks revealed significantly less glycation in animals co-administered allulose compared to those exposed to stevia. These results suggest allulose is associated with less AGE formation compared to fructose or glucose, and support its safety as a low-calorie sugar alternative. Full article

Previous studies involving workers at brick kilns in the Kathmandu Valley of Nepal have investigated chronic exposure to hazardous levels of fine particulate matter (PM_2.5) common in ambient and occupational environments. Such exposures are known to cause and/or exacerbate chronic respiratory diseases, including chronic obstructive pulmonary disease (COPD) and asthma. However, there is a paucity of data regarding the status of systemic inflammation observed in exposed workers at brick manufacturing facilities within the country. In the current study, we sought to elucidate systemic inflammatory responses by quantifying the molecular cytokine/chemokine profiles in serum from the study participants. A sample of participants were screened from a kiln in Bhaktapur, Nepal (n = 32; 53% female; mean ± standard deviation: 28.42 ± 11.47 years old) and grouped according to job category. Blood was procured from participants on-site, allowed to clot at room temperature, and centrifuged to obtain total serum. A human cytokine antibody array was used to screen the inflammatory mediators in serum samples from each of the participants. For the current study, four job categories were evaluated with n = 8 for each. Comparisons were generated between a control group of administration workers vs. fire master workers, administration workers vs. green brick hand molders, and administration workers vs. top loaders. We discovered significantly increased concentrations of eotaxin-1, eotaxin-2, GCSF, GM-CSF, IFN-γ, IL-1α, IL-1β, IL-6, IL-8, TGF-β1, TNF-α, and TIMP-2 in serum samples from fire master workers vs. administration workers (p < 0.05). Each of these molecules was also significantly elevated in serum from green brick hand molders compared to administration workers (p < 0.05). Further, each molecule in the inflammatory screening with the exception of TIMP-2 was significantly elevated in serum from top loaders compared to administration workers (p < 0.05). With few exceptions, the fire master workers expressed significantly more systemic inflammatory molecular abundance when compared to all other job categories. These results reveal an association between pulmonary exposure to PM_2.5 and systemic inflammatory responses likely mediated by cytokine/chemokine elaboration. The additional characterization of a broader array of inflammatory molecules may provide valuable insight into the susceptibility to lung diseases among this population. Full article

The global rise in type 2 diabetes (T2D) and obesity necessitates innovative dietary interventions. This study investigates the effects of allulose, a rare sugar shown to reduce blood glucose, in a rat model of diet-induced obesity and T2D. Over 12 weeks, we hypothesized that allulose supplementation would improve body weight, insulin sensitivity, and glycemic control. Our results showed that allulose mitigated the adverse effects of high-fat, high-sugar diets, including reduced body weight gain and improved insulin resistance. The allulose group exhibited lower food consumption and increased levels of glucagon-like peptide-1 (GLP-1), enhancing glucose regulation and appetite control. Additionally, allulose prevented liver triglyceride accumulation and promoted mitochondrial uncoupling in adipose tissue. These findings suggest that allulose supplementation can improve metabolic health markers, making it a promising dietary component for managing obesity and T2D. Further research is needed to explore the long-term benefits and mechanisms of allulose in metabolic disease prevention and management. This study supports the potential of allulose as a safe and effective intervention for improving metabolic health in the context of dietary excess. Full article

RAGE (receptor for advanced glycation end-products) represents a class of multi-ligand pattern recognition receptors highly expressed in the vertebrate lung. Our previous work demonstrated unique patterns of RAGE expression in the developing murine lung and regulation by key transcription factors including NKX2.1 and FoxA2. The current investigation employed conditional lung-specific upregulation via a TetOn transgenic mouse model (RAGE TG) and nontransgenic controls. RAGE expression was induced in RAGE TG mice throughout gestation (embryonic day, E0-E18.5) or from E15.5-E18.5 and compared to age-matched controls. High-resolution respirometry was used to assess mitochondrial respiration and context was provided by quantifying ATP and reactive oxygen species (ROS) generation. Lung lysates were also screened by immunoblotting for MAPK/PI3K signaling intermediates. RAGE upregulation increased mitochondrial oxygen consumption in the E0-E18.5 and E15.5-E18.5 groups compared to controls. RAGE TG mice also had increased ATP concentrations, which persisted even after controlling for oxygen consumption. In contrast, ROS generation was diminished in RAGE TG animals compared to controls. Lastly, in both RAGE TG groups, pERK and pp38 were significantly decreased, whereas pAKT was significantly elevated, suggesting that RAGE signaling is likely perpetuated via pAKT pathways. Together, these data demonstrate that despite lung hypoplasia in RAGE TG mice, the remaining tissue experiences a favorable shift in mitochondrial bioenergetics without excessive redox assault and a preference for AKT signaling over ERK or p38. Full article

Air pollution poses a significant global health risk, with fine particulate matter (PM_2.5) such as diesel exhaust particles (DEPs) being of particular concern due to their potential to drive systemic toxicities through bloodstream infiltration. The association between PM_2.5 exposure and an increased prevalence of metabolic disorders, including obesity, metabolic syndrome, and type 2 diabetes mellitus (T2DM), is evident against a backdrop of rising global obesity and poor metabolic health. This paper examines the role of adipose tissue in mediating the effects of PM_2.5 on metabolic health. Adipose tissue, beyond its energy storage function, is responsive to inhaled noxious stimuli, thus disrupting metabolic homeostasis and responding to particulate exposure with pro-inflammatory cytokine release, contributing to systemic inflammation. The purpose of this study was to characterize the metabolic response of adipose tissue in mice exposed to either DEPs or room air (RA), exploring both the adipokine profile and mitochondrial bioenergetics. In addition to a slight change in fat mass and a robust shift in adipocyte hypertrophy in the DEP-exposed animals, we found significant changes in adipose mitochondrial bioenergetics. Furthermore, the DEP-exposed animals had a significantly higher expression of adipose inflammatory markers compared with the adipose from RA-exposed mice. Despite the nearly exclusive focus on dietary factors in an effort to better understand metabolic health, these results highlight the novel role of environmental factors that may contribute to the growing global burden of poor metabolic health. Full article

Exposure to secondhand smoke (SHS) during fetal development results in negative postnatal effects, including altered organ development, changes in metabolism, and increased risk of respiratory illness. Previously, we found the induction of intrauterine growth restriction (IUGR) dependent on the expression of the receptor for advanced glycation end-products (RAGE) in mice treated with SHS. Furthermore, antenatal SHS exposure increases RAGE expression in the fetal lung. Our objective was to determine the postnatal effects of antenatal SHS treatment in 4- and 12-week-old offspring. Pregnant animals were treated with SHS via a nose-only delivery system (Scireq Scientific, Montreal, Canada) for 4 days (embryonic day 14.5 through 18.5), and offspring were evaluated at 4 or 12 weeks of age. Animal and organ weights were measured, and lungs were histologically characterized. Blood pressure and heart rates were obtained, and RAGE protein expression was determined in the lungs of control and treated animals. We observed the following: (1) significant decreases in animal, liver, and heart weights at 4 weeks of age; (2) increased blood pressure in 4-week-old animals; and (3) increased RAGE expression in the lungs of the 4-week-old animals. Our results suggest an improvement in these metrics by 12 weeks postnatally such that measures were not different regardless of RA or SHS exposure. Increased RAGE expression in lungs from 4-week-old mice antenatally treated with SHS suggests a possible role for this important smoke-mediated receptor in establishing adult disease following IUGR pregnancies. Full article

This study aimed to determine the impact of various fast-interrupting shakes on markers of glycemic control including glucose, β-hydroxybutyrate (BHB), insulin, glucagon, GLP-1, and GIP. Twenty-seven sedentary adults (twelve female, fifteen male) with overweight or obesity completed this study. One condition consisted of a 38-h water-only fast, and the other two conditions repeated this, but the fasts were interrupted at 24 h by either a high carbohydrate/low fat (HC/LF) shake or an isovolumetric and isocaloric low carbohydrate/high fat (LC/HF) shake. The water-only fast resulted in 135.3% more BHB compared to the HC/LF condition (p < 0.01) and 69.6% more compared to the LC/HF condition (p < 0.01). The LC/HF condition exhibited a 38.8% higher BHB level than the HC/LF condition (p < 0.01). The area under the curve for glucose was 14.2% higher in the HC/LF condition than in the water condition (p < 0.01) and 6.9% higher compared to the LC/HF condition (p < 0.01), with the LC/HF condition yielding 7.8% more glucose than the water condition (p < 0.01). At the 25-h mark, insulin and glucose-dependent insulinotropic polypeptide (GIP) were significantly elevated in the HC/LF condition compared to the LC/HF condition (p < 0.01 and p = 0.02, respectively) and compared to the water condition (p < 0.01). Furthermore, insulin, GLP-1, and GIP were increased in the LC/HF condition compared to the water condition at 25 h (p < 0.01, p = 0.015, and p < 0.01, respectively). By the 38-h time point, no differences were observed among the conditions for any of the analyzed hormones. While a LC/HF shake does not mimic a fast completely, it does preserve some of the metabolic changes including elevated BHB and glucagon, and decreased glucose and insulin compared to a HC/LF shake, implying a potential for improved metabolic health. Full article