UCP1 Expression Research Articles

Diet-induced obesity and aging-induced upregulation of Trib3 interfere with energy homeostasis by downregulating the thermogenic capacity of BAT

AbstractCharacterized by UCP1 expression and abundant mitochondria, brown adipose tissue (BAT) plays a crucial role in energy balance by converting chemical energy into heat through the cost of ATP production. In this study, it was demonstrated that Trib3 is a critical determinant of BAT-mediated energy expenditure and whole-body energy homeostasis. Under 60% high-fat diet conditions, Trib3 expression in BAT was elevated. Mice deficient in Trib3 are resistant to diet-induced obesity and exhibit improved glucose homeostasis due to enhanced BAT activity. Furthermore, brown adipocyte progenitor cells (APCs) lacking Trib3 exhibited increased proliferation and promoted brown adipocyte differentiation and mitochondrial biogenesis, contributing to the increase in the maximal thermogenic capacity of BAT in Trib3-deficient mice. Mechanistically, it was discovered that Trib3 expression is upregulated by free fatty acids at the transcriptional level and synergistically upregulated by DAG-PKC at the posttranslational level. This occurs through the modulation of COP1-mediated Trib3 protein turnover. Interestingly, the level of Trib3 expression in BAT increased with age. Trib3 knockout mice were protected from aging-related weight gain and impaired glucose homeostasis. These results suggest that Trib3 acts as an obesity- and aging-associated factor that negatively regulates BAT activity and that the loss of Trib3 may provide a beneficial approach to prevent obesity and aging-associated metabolic syndrome by increasing the thermogenic capacity of BAT.

Targeting Dlat-Trpv3 pathway by hyperforin elicits non-canonical promotion of adipose thermogenesis as an effective anti-obesity strategy

IntroductionPromoting adipose thermogenesis is considered as a promising therapeutic intervention in obesity. However, endeavors to develop anti-obesity medications by targeting the canonical thermogenesis regulatory pathway, particularly β3-adrenergic receptor (β3-AR)-dependent mechanism, have failed due to the off-target effects of β3-AR agonists, exacerbating the risk of cardiovascular disease. Hyperforin (HPF), a natural compound extracted from the traditional herbal St. John’s Wort, binds to Dihydrolipoamide s-acetyltransferase (Dlat) and exerts effective anti-obesity properties through promoting adipose thermogenesis. ObjectivesThe objective of this study was to investigate the oral efficacy and pharmacokinetics profile of HPF, and explore the detailed mechanism by which Dlat modulates HPF-mediated adipose thermogenesis. MethodsTo assess the anti-obesity efficacy of orally administered HPF in vivo, Dlat heterozygous knockout (Dlat+/-) mice and wild-type (WT) mice, both fed a high-fat diet (HFD), underwent a validation process that involved the use of metabolic cages, NMR analysis, and infrared imaging. Sprague Dawley rats were employed to determine the pharmacokinetic parameters of HPF. Seahorse assays, JC-1 staining, qPCR, and immunoblotting were performed to evaluate cellular thermogenic efficacy of HPF and Dlat in vitro. ResultsOur study uncovered a non-canonical thermogenesis pathway involving Dlat, transient receptor potential vanilloid 3 (Trpv3, a calcium channel) and AMPK. Dlat interacted with Trpv3 to activate it, resulting in an increase in intracellular calcium (Ca2+) and the activation of Camkkβ. Camkkβ then stimulated AMPK, leading to elevated Ucp1 expression and initiating adipose thermogenesis. HPF promoted thermogenesis in adipose tissues through enhancing the Dlat-Trpv3 interaction independently of β3­AR, causing minimal cardiac side effects. Notably, HPF’s thermogenic effects were reduced in Dlat+/- mice. Moreover, HPF exerted favorable oral bioavailability, a relatively long half-life, and extensive distribution within adipose tissues. ConclusionIn summary, our study demonstrates that HPF targets a novel mechanism for promoting adipose thermogenesis and exhibits potent and safe anti-obesity efficacy.

High-iron diet damages brown adipose tissue mitochondria and exacerbates metabolic hazards of a high-fat diet

Metabolic diseases may be prevented by reducing carbohydrate intake and replacing plant-based diets with animal-based ones low in carbohydrates but high in protein, fat, and iron. While the effects of sugars on metabolic diseases are well-known, the role of iron remains unclear. This study aimed to explore the effects of a high-fat high-iron animal diet on body metabolism in mice. Micro-PET imaging was used to assess 18-F-labelled glucose uptake in BAT, and the morphology, respiratory function, and oxidative stress of BAT mitochondria were examined. The underlying mechanisms were elucidated by analyzing the expression of UCP-1, PGC-1α and PPARα. The high-iron high-fat diet increased appetite, impaired glucose tolerance, and reduced insulin sensitivity. Additionally, the high-iron diet promoted gluconeogenesis only in the absence of high-fat levels. Both high-iron and high-fat diets suppressed BAT activity, increased mitochondrial oxidative stress, decreased mitochondrial respiratory function, and lowered thermogenic gene expression. Weight loss strategies focusing solely on reducing carbohydrates and increasing animal foods, like ketogenic diets, may have long-term detrimental effects on metabolic health. Prioritizing dietary diversity and monitoring overall caloric intake is advisable for optimal outcomes.

Thermoregulation and survival during sepsis: insights from the cecal ligation and puncture experimental model

BackgroundSepsis remains a major global health concern due to its high prevalence and mortality. Changes in body temperature (Tb), such as hypothermia or fever, are diagnostic indicators and play a crucial role in the pathophysiology of sepsis. This study aims to characterize the thermoregulatory mechanisms during sepsis using the cecal ligation and puncture (CLP) model and explore how sepsis severity and ambient temperature (Ta) influence Tb regulation and mortality. Rats were subjected to mild or severe sepsis by CLP while housed at thermoneutral (28 °C) or subthermoneutral (22 °C) Ta, and their Tb was monitored for 12 h. Blood and hypothalamus were collected for cytokines and prostaglandin E2 (PGE2) analysis.ResultsAt 28 °C, febrile response magnitude correlated with sepsis severity and inflammatory response, with tail vasoconstriction as the primary heat retention mechanism. At 22 °C, Tb was maintained during mild sepsis but dropped during severe sepsis, linked to reduced UCP1 expression in brown adipose tissue and less effective vasoconstriction. Despite differences in thermoregulatory responses, both Ta conditions induced a persistent inflammatory response and increased hypothalamic PGE2 production. Notably, mortality in severe sepsis was significantly higher at 28 °C (80%) compared to 22 °C (0%).ConclusionsOur findings reveal that ambient temperature and the inflammatory burden critically influence thermoregulation and survival during early sepsis. These results emphasize the importance of considering environmental factors in preclinical sepsis studies. Although rodents in experimental settings are often adapted to cold environments, these conditions may not fully translate to human sepsis, where cold adaptation is rare. Thus, researchers should carefully consider these variables when designing experiments and interpreting translational implications.Graphical Graphical representation of the thermoregulatory and inflammatory responses to mild and severe sepsis in rats housed at thermoneutral (28 °C) and subthermoneutral (22 °C) ambient temperatures (Ta). The model highlights distinct body temperature outcomes: fever and hypothermia. At thermoneutral Ta, severe sepsis induces a high fever, associated with increased hypothalamic PGE2, cytokine levels, and mortality, while mild sepsis leads to a moderate fever. In contrast, at subthermoneutral Ta, severe sepsis results in hypothermia with decreased UCP1 expression and lower mortality, whereas mild sepsis maintains normal body temperature. The impact of Ta on sepsis severity, thermoregulatory mechanisms, and survival is emphasized.

In-vitro modulation of glucose and lipid metabolism by Lentinula edodes extracts in obesity and type 2 diabetes models

IntroductionLentinula edodes (shiitake mushroom) has been integral to Traditional Chinese Medicine (TCM) for centuries, with its cultivation dating back to the Song dynasty (960–1127) in China. Traditionally valued for its immune-boosting properties, L. edodes is now being studied for its potential in managing metabolic disorders like obesity and type 2 diabetes. This study examines the effects of L. edodes fruiting body extract on key metabolic pathways related to glucose metabolism and lipid regulation. MethodsFruiting body extracts of Lentinula edodes including water, ethanolic, methanolic, and hydroalcoholic (50:50, 75:25, 25:75) were tested on L6 myoblasts. The study evaluated glucose uptake, GLUT4 expression, p-AMPK activation, and gene expression levels of PPARγ, AMPK, UCP-1, and FASN. Comparisons were made with control groups and standards like berberine and insulin. ResultsThe hydroalcoholic extracts (50:50 and 75:25) significantly enhanced glucose uptake (p < 0.001) and GLUT4 translocation, similar to the effects of insulin (p < 0.0001) and berberine (p < 0.0001). These extracts also upregulated p-AMPK (p < 0.0001) and UCP-1 expression (7.621), indicating improved insulin sensitivity and thermogenic activity. Additionally, these extracts differentially regulated PPARγ and FASN, suggesting a complex interaction with lipid metabolism. Notably, FASN expression was highly upregulated in water extract (37.792), indicating potential implications for fatty acid synthesis and storage. DiscussionLentinula edodes shows significant potential as a functional food for managing obesity and diabetes, supporting traditional TCM practices with modern scientific evidence. The study suggests that L. edodes can modulate key metabolic pathways such as glucose uptake, AMPK signalling, PPARγ regulation, and upregulation of FASN and UCP-1, making it a promising natural therapeutic agent. Further research, including clinical trials, is necessary to confirm these benefits in humans and explore the underlying mechanisms.

Palm and Interesterified palm oil-enhanced brown fat whitening contributes to metabolic dysfunction in C57BL/6J mice

Palm oil is widely used in the food industry owing to its high stability and versatility. The interesterified version has been used as an alternative to oils rich in trans fatty acids. However, the health effects of these vegetable oils are not yet fully understood. We hypothesized that the consumption of palm oil (non-interesterified and interesterified), even without excessive amounts of energy and lipids in the diet, could lead to morphofunctional changes in brown adipose tissue (BAT). To this end, male C57BL/6J mice were divided into three dietary groups (n = 10 each): soybean oil (SO), palm oil (PO), and interesterified palm oil (IPO) for 10 weeks. The PO and IPO groups had significant increases in the visceral fat mass and interscapular BAT (iBAT) lipid content. In iBAT, the PO and IPO groups showed lower mRNA expression of Ucp1, Adrb3, and Pgc1a, while the PO also showed lower mRNA levels of Ppara and Ampk, and the IPO showed lower Prdm16 expression. Moreover, PO had higher Il6 expression and lower catalase activity, while the IPO showed an upregulated Tnfa expression and lower catalase activity, but higher antioxidant activity of the glutathione peroxidase (GPx) enzyme. The consumption of PO and IPO had negative effects on weight and body fat, including the impairment of iBAT function. Our findings give rise to apprehensions regarding the safety and consequences of consuming palm and interesterified palm oils for energy metabolism.

Dietary Lactate Intake and Physical Exercise Synergistically Reverse Brown Adipose Tissue Whitening to Ameliorate Diet-Induced Obesity.

Physical exercise represents an effective strategy for combating obesity via brown adipose tissue (BAT) activation, but the mechanism remains unclear. In this study, we demonstrated that the cooperation between lactate and adrenoceptor signaling regulated BAT activity during exercise. The lactate receptor GPR81 was highly expressed in the BAT of lean mice, whereas its expression was markedly decreased in obese mice. Notably, the level of GPR81 in BAT could be upregulated by exercise. The blockade of lactate production or GPR81 significantly impaired exercise-induced BAT activation. In addition, dietary lactate intake enhanced the efficacy of physical exercise in alleviating BAT whitening in obese mice, as evidenced by the improved mitochondrial ultrastructure, reduced lipid droplets, increased UCP1 expression, and elevated mitochondrial DNA content. Further data indicated that norepinephrine triggered UCP1 activation through both the cAMP/PKA and Ca2+/CaMK pathways during exercise, while lactate mediated this process via the GPR81-Ca2+/CaMK cascade. Our findings unveil a novel mechanism in the regulation of BAT function by physical exercise, providing a promising lifestyle intervention to improve metabolic health.

Sleep deprivation stimulates adaptive thermogenesis by activating AMPK pathway in mice.

Sleep deprivation (SD) can affect the adaptive thermogenesis in laboratory rodents, but the molecular mechanism and the crosstalk with other organs remain largely unknown. In order to investigate the effects and mechanisms of SD on thermoregulation and energy metabolism, here we measured the changes of body weight, body fat mass, body temperature, resting metabolic rate (RMR), and thermogenic gene expression in brown adipose tissue (BAT), white adipose tissue (WAT), skeleton muscle and liver in C57BL/6J mice during 7-day SD with rotating rod sleep deprivation device. Results showed that compared with the control group, the body weight and body fat mass of SD mice were decreased and RMR of SD mice increased. The gene expression of Ampk, Pgc1α and Ucp1 which related to thermogenesis in BAT and WAT were significantly increased, and the expression of Ampk, Serca1, Serca2 and Ucp3 which related to thermogenesis in skeletal muscle were significantly increased in SD mice. Taken together, these data demonstrated that 7-day SD enhanced the adaptive thermogenesis in mice by activating AMPK, including the upregulation of the AMPK - PGC1α - UCP1 pathway in BAT, and the AMPK - UCP3 and SLN - SERCA pathway in skeleton muscle. Our data provide the molecular evidence for SD-stimulated adaptive thermogenesis and energy metabolism in small mammals.

Hypoxia-inducible factor-1α-deficient adipose-tissue macrophages produce the heat to mediate lipolysis of white adipose tissue through uncoupling protein-1

BackgroundUncoupling protein 1 (UCP1) is a proton uncoupler located across the mitochondrial membrane generally involved in thermogenesis of brown adipose tissues. Although UCP1 is known to be strongly expressed in brown adipocytes, recent evidence suggest that white adipocytes can also express UCP1 under certain circumstances such as cold- or β-adrenergic receptor-stimulation, allowing them to acquire brown adipocyte-like features thereby becoming 'beige’ adipocytes.ResultsIn this study, we report that UCP1 can be expressed in adipose-tissue macrophages (ATM) lacking functional hypoxia-inducible factor-1 (HIF-1) and this does not require cold- nor β-adrenergic receptor activation. By using myeloid-specific Hif-1α knockout (KO) mice, we observed that these mice were protected from diet-induced obesity and exhibited an improved thermogenic tolerance upon cold challenge. ATM isolated from white adipose tissues (WAT) of these mice fed with high fat diet exhibited significantly higher M2-polarization, decreased glycolysis, increased mitochondrial functions and acetyl-CoA levels, along with increased expression of Ucp1, peroxisome proliferator activated receptor-gamma co-activator-1a, and others involved in histone acetylation. Consistent with the increased Ucp1 gene expression, these ATM produced a significant amount of heat mediating lipolysis of co-cultured adipocytes liberating free fatty acid. Treating ATM with acetate, a substrate for acetyl-CoA synthesis was able to boost the heat production in wild-type or Hif-1α-deficient but not UCP1-deficient macrophages, indicating that UCP1 was necessary for the heat production in macrophages. Lastly, we observed a significant inverse correlation between the number of UCP1-expressing ATM in WAT and the body mass index of human individuals.ConclusionsUCP1-expressing ATM produce the heat to mediate lipolysis of adipocytes, indicating that this can be a novel strategy to treat and prevent diet-induced obesity.

Regulatory effects of yam (Dioscorea opposita Thunb.) glycoprotein on energy metabolism in C2C12 and 3T3-L1 cells and on crosstalk between these two cells

Ethnopharmacological relevanceControlling energy and regulating metabolism have been key strategies in the treatment of metabolic disorders such as obesity. Yam glycoprotein (Y-Gly) is a polysaccharide-protein complex extracted from Chinese yam that has beneficial effects on glucose and lipid metabolism. This study aimed to investigate the role of Y-Gly in regulating energy metabolism in C2C12 and 3T3-L1 cells. Materials and methodsY-Gly was subjected to extraction and chemo-profiling. Staining methods, assay kits, Western Blot and transcriptomics were mainly used to determine the role of Y-Gly. Additionally, the study sought to examine the impact of Y-Gly on white adipose browning in 3T3-L1 cells, employing a cell co-culture technique. ResultsY-Gly promoted myotube differentiation in C2C12 myoblasts, increased cellular glucose consumption, promoted ATP synthesis and mitochondrial biogenesis, and played an active role in energy expenditure and glycolipid metabolism related pathways such as AMPK and MAPK. The introduction of Y-Gly inhibited lipid accumulation after lipogenesis in 3T3-L1 cells, facilitated induction of white adipose browning related proteins such as PPARγ and UCP1 expression, and the effect was more significant after cell co-culture. ConclusionsY-Gly regulates glucose and lipid metabolism by activating the key proteins in the aforementioned pathways, and plays a role in energy metabolism regulation through crosstalk between muscle and adipose tissues. This suggests a possible role of Y-Gly in metabolism-related diseases.

Two Regions with Different Expression of Lipogenic Enzymes in Rats' Posterior Subcutaneous Fat Depot.

Lipid metabolism in various adipose tissue depots can differ vastly. This also applies to lipogenesis, the process of synthesizing fatty acids from acetyl-CoA. This study compared the expression of some lipogenic enzymes: fatty acid synthase (FASN), ATP-citrate lyase (ACLY), and malic enzyme 1 (ME1) in different regions of the posterior subcutaneous adipose tissue in rats. Methods and Results: Posterior subcutaneous adipose tissue collected from twelve-month-old Wistar rats was divided into six parts (A-F). The expression of genes encoding lipogenic enzymes was assessed by measuring their activity and mRNA levels using real-time PCR. In the gluteal region of the fat pad, there were much higher levels of activity and mRNA for these lipogenic enzymes compared to the dorsolumbar region. The mRNA level of FASN increased by more than twentyfold, whereas the level of ME1 and ACLY increased eight- and fivefold respectively. This phenomenon was observed in both old and young animals. Furthermore, the lack of uncoupling protein one (Ucp1) expression suggests that neither the presence of brown adipocytes in the gluteal part nor the transformation of white adipocytes into beige contributed to the observed differences. Conclusion: These results indicate that the gluteal white adipose tissue appears to be a unique and separate subcutaneous fat depot.

SnRNA-seq of adipose tissues reveals the potential cellular and molecular mechanisms of cold and disease resistance in Mongolian cattle

BackgroundMongolian cattle are local breeds in northern China with excellent adaptability to harsh environmental conditions. Adipose tissues play essential roles in tolerance to cold and disease, but the associated cellular and molecular mechanisms are unclear.MethodsSingle-nucleus RNA sequencing (snRNA-seq) was performed on the adipose tissues from the subcutaneous (SAT), greater omentum (OAT) and perirenal (PAT) of 3 healthy cattle. The adipogenic trajectory was analyzed, and the functional roles of gene of interest were verified in vitro.ResultsThere were different cell subpopulations in adipose tissues. The lipid-deposition adipocytes identified by the PTGER3 marker exhibited outstanding characteristics in SAT. In PAT and OAT, aldosterone was expressed to provide clues for the differential brown adipocytes. Among the DEGs by comparing OAT with SAT and PAT with OAT, C3 was significantly expressed in most of the cell populations in SAT. G0S2, LIPE, LPIN1, PTGER3 and RGCC took part in the adipogenic trajectory from preadipocyte commitment to mature adipocytes. S100A4 expression affected Ca2+ signaling and the expression of UCP1 ~ 3, FABP4 and PTGER3.ConclusionThe cell heterogeneity and genes expressed in adipose tissues of Mongolian cattle not only determine the endocrine and energy storage, but contribute to adapt to cold and disease resistance.

Targeted Deletion of Fibroblast Growth Factor 23 Rescues Metabolic Dysregulation of Diet-induced Obesity in Female Mice.

Fibroblast growth factor 23 (FGF23) is a bone-secreted protein widely recognized as a critical regulator of skeletal and mineral metabolism. However, little is known about the nonskeletal production of FGF23 and its role in tissues other than bone. Growing evidence indicates that circulating FGF23 levels rise with a high-fat diet (HFD) and they are positively correlated with body mass index (BMI) in humans. In the present study, we show for the first time that increased circulating FGF23 levels in obese humans correlate with increased expression of adipose Fgf23 and both positively correlate with BMI. To understand the role of adipose-derived Fgf23, we generated adipocyte-specific Fgf23 knockout mice (AdipoqFgf23Δfl/Δfl) using the adiponectin-Cre driver, which targets mature white, beige, and brown adipocytes. Our data show that targeted ablation of Fgf23 in adipocytes prevents HFD-fed female mice from gaining body weight and fat mass while preserving lean mass but has no effect on male mice, indicating the presence of sexual dimorphism. These effects are observed in the absence of changes in food and energy intake. Adipose Fgf23 inactivation also prevents dyslipidemia, hyperglycemia, and hepatic steatosis in female mice. Moreover, these changes are associated with decreased respiratory exchange ratio and increased brown fat Ucp1 expression in knockout mice compared to HFD-fed control mice (Fgf23fl/fl). In conclusion, this is the first study highlighting that targeted inactivation of Fgf23 is a promising therapeutic strategy for weight loss and lean mass preservation in humans.

Boosting Health Benefits in Vegetables: A Novel Ultraviolet B (UVB) Device for Rapid At-Home Enhancement of Phytochemicals and Bioactivity.

The consumption of vegetables is essential for reducing the risk of noncommunicable diseases, yet global intake falls short of recommended levels. Enhancing the nutraceutical content of vegetables through postharvest abiotic stress, such as ultraviolet B (UVB) radiation, offers a promising solution to increase health benefits. This study developed a user-friendly, at-home UVB device designed to increase the phytochemical content in common vegetables like carrots, lettuce, and broccoli. The device applies UVB radiation (305-315 nm) to fresh-cut vegetables, optimizing exposure time and intensity to maximize nutraceutical enrichment. The results demonstrated that UVB exposure increased the phenolic content by 44% in carrots, 58% in broccoli, and 10% in lettuce, with chlorogenic acid levels rising by 367% in lettuce, 547% in broccoli, and 43% in carrots after 48 h of storage. UVB treatment also enhanced antioxidant activity by up to 41% in broccoli and anti-inflammatory potential by 22% in carrots. In terms of gene expression, UVB treatment upregulated UCP-1 expression by 555% in carrots, enhanced thermogenesis, and increased SIRT-1 and ATGL expression by over 200%, promoting lipid metabolism. This process provides a convenient and efficient method for consumers to boost the health benefits of their vegetables. The study concludes that UVB-induced abiotic stress is an effective strategy to improve vegetable nutritional quality, offering a novel approach to increasing bioactive compound intake and aiding in the prevention of diet-related diseases.

Tissue oxidative stress and expression of chicken UCP and ANT mRNA in laying hens exposed to acute cold stress

ABSTRACT 1. Exposure to stress alters normal homoeostasis and, hence, the antioxidant defence system. The aim of this study was to examine the effect of acute cold temperature on the antioxidant defence system in hens. 2. Hy-line grey commercial layers (80 40-week-old) were randomly assigned to one of eight groups. In groups 1 to 5, hens were exposed to low temperature at −8.68°C (cool stressed) for 2, 4, 6, 8 and 10 h, respectively. In groups 6 and 7, post 10 h cool stressed, hens were quickly transferred to room at 21°C to recovery for 2 h and 4h, respectively. In treatment groups 6 and 7, post 10 h cool stressed, hens were quickly transferred to room at 21°C for 2 h and 4 h, respectively. Group 8 was the control, where hens were housed under regular condition at 21°C as controls. 3. Antioxidant enzymes (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GPx) and malondialdehyde (MDA), in skeletal muscle, the kidney, liver and pancreas were measured. The transcription of avUCP and ANT mRNA was tested by RT-PCR. 4. The T-AOC activity was increased in the skeletal muscle of hens cold stressed for 2, 4, 6, 8 and 10 h and the 2 h recovery groups compared with control hens (p < 0.05). The GPx activity was increased in the liver and skeletal muscle after cold stress 4 h and in the pancreas of cold stress 2 h compared with the control group (p < 0.05). Antioxidant SOD activity was increased in the kidney after cold stress 6 h and in the liver after cold stress 10 h compared to the control group (p < 0.05). Measured MDA activity was increased in the pancreas after 2 h cold stress (p < 0.05). 5. UCP mRNA expression level was increased in the pectoral muscle for 2 h and 4 h recovery groups compared with the control hens (p < 0.05) and avian uncoupling protein (UPC), adenine nucleotide translocator (ANT) expression level was increased in the leg muscle of hens cold stress for 2, 6, 8 h and recovery 2 and 4 h. 6. The observed changes in the antioxidant defence system were tissue specific. Increments in levels of ANT (leg muscle) and UCP (pectoral and leg muscle) mRNA expression may be involved in the regulation of thermogenesis in skeletal muscle.

Phenotypic characteristics of adipocyte-like cells generated from C2C12 myoblasts cultured with chicken serum

The aim of this study was to clarify the transcriptional and metabolic characteristics of C2C12 myoblasts cultured in Dulbecco's Modified Eagle Medium (DMEM) containing 20 % chicken serum (CHS) (C2C12–CHS cells) compared with C2C12 myoblasts cultured in DMEM containing 20 % fetal bovine serum (FBS) (C2C12-FBS cells). After 3 days of culture, C2C12–CHS cells showed a marked accumulation of lipid droplets, accompanied by increased expression levels of brown adipocyte-related genes (i.e., Bmp7, Prdm16, Ucp1, Cidea, Pgc1α, Cox7a1, Cox8, and β3-adorenoceptor). Furthermore, stimulation of β3-adorenoceptor by its selective agonist, mirabegron, increased the mRNA expression of Ucp1 and Pgc1α in C2C12–CHS cells. Wide-targeted metabolomic analysis performed by gas chromatography-tandem mass spectrometry revealed that the metabolic profile of C2C12–CHS cells was obviously different to that of C2C12-FBS cells. Additionally, the metabolomic analysis indicated that β3-adrenoceptor stimulation by mirabegron upregulated energy metabolism in C2C12–CHS cells as seen in brown adipocytes. These results suggest that C2C12–CHS cells may differentiate into brown adipocyte-like cells, accompanied by increased functional β3-adrenoceptor.

Maternal Obesity Alters Placental and Umbilical Cord Plasma Oxidative Stress, a Cross-Sectional Study.

Maternal obesity has been shown to impair the oxidative status in the placenta and newborns, potentially leading to adverse pregnancy outcomes and long-term effects on the programming of offspring metabolic status. This study aimed to investigate the impact of maternal obesity on maternal and umbilical cord plasma oxidative status, as well as placental oxidative adaptation. Maternal obesity (n = 20), defined as a pre-pregnancy BMI ≥ 25 kg/m2, and maternal leanness (n = 20), defined as a pre-pregnancy BMI < 23 kg/m2, were the group categories used in this study. Both groups were matched according to gestational age at delivery. Maternal blood, umbilical cord blood, and placental tissue were collected to assess nutritional content (cholesterol, triglyceride, and protein), oxidative stress markers (MDA and protein carbonyl), and antioxidant activity (SOD and catalase). Placental protein expression (SOD2, catalase, UCP2, and Nrf2) was evaluated using Western blot analysis. Catalase activity in maternal plasma significantly increased in the maternal obesity group (p = 0.0200), with a trend toward increased MDA and protein carbonyl levels. In umbilical cord plasma, triglyceride, protein carbonyl, and catalase activity were significantly elevated in the maternal obesity group compared with the lean controls (p = 0.0482, 0.0291, and 0.0347, respectively). Placental protein expression analysis revealed significantly decreased SOD2 (p = 0.0011) and catalase (p < 0.0001), along with Nrf2 downregulation (p < 0.0001). An increase in mitochondrial antioxidant UCP2 expression was observed (p = 0.0117). The neonatal protein carbonyl levels positively correlated with placental protein carbonyl (r = 0.7405, p < 0.0001) and negatively correlated with maternal catalase activity (r = -0.4332, p = 0.0052). This study thus provides evidence that maternal obesity is associated with placental and fetal oxidative stress, alongside a concurrent increase in placental antioxidant UCP2 expression.

7951 The Response of HPT Axis &amp; BAT to Cold Exposure Is Delayed in Female Rats Compared to Males

Abstract Disclosure: A. Gutiérrez-Mata: None. L. Jaimes-Hoy: None. I. Sotelo-Rivera: None. F. Romero-Arteaga: None. R.M. Uribe: None. J.L. Charli: None. P. Joseph-Bravo: None. Cold exposure activates the sympathetic nervous system releasing NE in thermogenic brown adipose tissue (BAT) and in parallel, the Hypothalamus-Pituitary-Thyroid (HPT) axis, increasing synthesis and release of hypothalamic-TRH, pituitary-TSH, and thyroid hormones T4 and T3; T4 in concert with NE induce brown adipose tissue (BAT) thermogenesis through stimulation of deiodinase 2 (Dio2), and uncoupling protein 1 (Ucp1) expression. These changes are detected within the first hour in male rats [J Neuroendo 12:861, 2014] while in females, only in ovariectomized [J Neuroendocrinol 21:439, 2009]. Given the thermogenic effect of ovarian hormones, we hypothesized that females could respond to longer exposures. Female Wistar rats were exposed individually to 5°C for 1 to 5h and compared to male’s acute response (15 min to 4h); controls were moved individually to a nearby room at 22°C for similar times. Rats were euthanized by guillotine, rectal temperature was immediately measured, trunk blood collected, serum separated, and tissues kept at -70°C. Hormone concentrations were quantified in serum by RIA and ELISA, and gene expression in paraventricular nucleus (PVN), anterior pituitary (AP), and BAT by RT-PCR or qPCR. Body temperature of cold-exposed males was higher than isolated controls since the first 30min, Trh expression increased at 1h in the paraventricular nucleus (PVN), TSH release from 15 min up to 2 hours, T4 levels peaked until 4h, and T3 increased after 2h as in [Endocrinology 58:140, 1993]; Trhr1 in AP reached its lowest levels at 2h. In BAT, Dio2 expression peaked at 1h and subsequently decreased. Ucp1 increased from 30 min and remained elevated until 4h, Adrb3, and Ppargc1a expressions were highest at 4h. Cold exposure in females decreased body temperature after 4 hours when Trh PVN expression increased and that of TRH receptor 1 (Trhr1) in AP was lowest; TRH degrading enzyme (Trhde) expression peaked after 2h of cold and subsequently decreased at 4h. TSH in serum increased at 2h and then returned to control levels, T4 slightly increased at 3h, and T3 peaked at 5h. Progesterone serum concentration increased from 2h and peaked at 4h. No changes were found in estradiol serum concentration. In BAT, Dio2 expression increased from 2 to 4h, Ucp1 at 3 and 5h while that of β3 adrenergic receptor (Adrb3) decreased at 2h but rose reaching a peak at 4h. In contrast, expression of Pgc1α -the major transcriptional coactivator of Ucp1- rapidly increased (1h) decreasing afterward. The data suggest that when the ambient temperature decreases, the sympathetic system is activated including stimulation of progesterone, and supports a delayed response of female HPT axis to cold exposure, compared to male’s leading to the proposal that when female body temperature diminishes, the HPT axis and thyroid hormone-induced thermogenesis are activated.Funding: DGAPA IN217422, PAEP, CONAHCYT 790605. Presentation: 6/2/2024

Myricetin and myricitrin indirectly and directly increases uncoupling protein-1 mRNA expression in C3H10T1/2 beige adipocytes

In thermogenic brown and beige adipocytes, the proton gradient formed by energy derived from nutrients such as lipids and carbohydrates is consumed by uncoupling protein-1 (UCP-1), resulting in thermogenesis without ATP production in the mitochondria. Accordingly, increased UCP-1 expression represents a crucial aspect of dietary management for individuals with overweight and obesity. Myricetin and its glycoside, myricitrin, are food-derived flavonoids that possess various beneficial effects. This is the first study to examine the effects of myricetin and myricitrin on the inflammation-inhibited expression of Ucp-1 using a modified cell-based assay with conditioned medium (CM). The CM derived from lipopolysaccharide (LPS)-activated RAW264.7 macrophages was observed to inhibit the Ucp-1 expression induced by adrenergic stimulation in 10T1/2 adipocytes. Conversely, the CM derived from activated macrophages treated with myricetin or myricitrin reversed this inhibition of Ucp-1 expression. Subsequently, the direct effects of both the compounds on basal and adrenaline-induced expression of Ucp-1 were investigated. In contrast to a previous report, myricetin and myricitrin did not increase the basal Ucp-1 mRNA expression in 10T1/2 adipocytes when treated during the differentiation-promoting period. However, we have found for the first time that both compounds enhanced the adrenergic sensitivity of 10T1/2 adipocytes when treated during the differentiation-inducing period. These results indicate that myricetin and myricitrin have indirect effects on inflammation-induced suppression and direct effects on adrenergic sensitivity, suggesting a novel mechanism that both compounds increase Ucp-1 expression in vivo by both indirect and direct effects, rather than by affecting basal expression.

Exploring the role of mitochondrial uncoupling protein 4 in brain metabolism: implications for Alzheimer's disease.

The brain's high demand for energy necessitates tightly regulated metabolic pathways to sustain physiological activity. Glucose, the primary energy substrate, undergoes complex metabolic transformations, with mitochondria playing a central role in ATP production via oxidative phosphorylation. Dysregulation of this metabolic interplay is implicated in Alzheimer's disease (AD), where compromised glucose metabolism, oxidative stress, and mitochondrial dysfunction contribute to disease progression. This review explores the intricate bioenergetic crosstalk between astrocytes and neurons, highlighting the function of mitochondrial uncoupling proteins (UCPs), particularly UCP4, as important regulators of brain metabolism and neuronal function. Predominantly expressed in the brain, UCP4 reduces the membrane potential in the inner mitochondrial membrane, thereby potentially decreasing the generation of reactive oxygen species. Furthermore, UCP4 mitigates mitochondrial calcium overload and sustains cellular ATP levels through a metabolic shift from mitochondrial respiration to glycolysis. Interestingly, the levels of the neuronal UCPs, UCP2, 4 and 5 are significantly reduced in AD brain tissue and a specific UCP4 variant has been associated to an increased risk of developing AD. Few studies modulating the expression of UCP4 in astrocytes or neurons have highlighted protective effects against neurodegeneration and aging, suggesting that pharmacological strategies aimed at activating UCPs, such as protonophoric uncouplers, hold promise for therapeutic interventions in AD and other neurodegenerative diseases. Despite significant advances, our understanding of UCPs in brain metabolism remains in its early stages, emphasizing the need for further research to unravel their biological functions in the brain and their therapeutic potential.