Forkhead Transcription Factor O1 Research Articles

FoxO1 knockdown inhibits RANKL-induced osteoclastogenesis by blocking NLRP3 inflammasome activation.

This study aimed to elucidate the connection between osteoclastic forkhead transcription factor O1 (FoxO1) and periodontitis and explore the underlying mechanism by which FoxO1 knockdown regulates osteoclast formation. A conventional ligature-induced periodontitis model was constructed to reveal the alterations in the proportion of osteoclastic FoxO1 in periodontitis via immunofluorescence staining. Additionally, RNA sequencing (RNA-seq) was performed to explore the underlying mechanisms of FoxO1 knockdown-mediated osteoclastogenesis, followed by western blotting, quantitative polymerase chain reaction, and enzyme-linked immunosorbent assay. FoxO1+ osteoclasts were enriched in the alveolar bone in experimental periodontitis. Moreover, FoxO1 knockdown led to impaired osteoclastogenesis with low expression of osteoclast differentiation-related genes, accompanied by an insufficient osteoclast maturation phenotype. Mechanistically, RNA-seq revealed that the nuclear factor kappa B (NF-κB) and nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome signaling pathways were inhibited in FoxO1-knockdown osteoclasts. Consistent with this, MCC950, an effective inhibitor of the NLRP3 inflammasome, substantially attenuated osteoclast formation. FoxO1 knockdown contributed to the inhibition of osteoclastogenesis by effectively suppressing NF-κB signaling and NLRP3 inflammasome activation. This prospective study reveals the role of FoxO1 in mediating osteoclastogenesis and provides a viable therapeutic target for periodontitis treatment.

Zuogui Jiangtang Qinggan Formula improves glucolipid metabolism in type 2 diabetes mellitus complicated with non-alcoholic fatty liver disease by regulating FoxO1/MTP/APOB signaling pathway

This study aimed to investigate the effect and mechanism of Zuogui Jiangtang Qinggan Formula(ZGJTQG) on the glucolipid metabolism of type 2 diabetes mellitus(T2DM) complicated with non-alcoholic fatty liver disease(NAFLD). NAFLD was induced by a high-fat diet(HFD) in MKR mice(T2DM mice), and a model of T2DM combined with NAFLD was established. Forty mice were randomly divided into a model group, a metformin group(0.067 g·kg~(-1)), and high-and low-dose ZGJTQG groups(29.64 and 14.82 g·kg~(-1)), with 10 mice in each group. Ten FVB mice of the same age were assigned to the normal group. Serum and liver tissue specimens were collected from mice except for those in the normal and model groups after four weeks of drug administration by gavage, and fasting blood glucose(FBG) and fasting insulin(FINS) levels were measured. The levels of total cholesterol(TC), triglyceride(TG), and low-density lipoprotein(LDL) were detected by the single reagent GPO-PAP method. Very low-density lipoprotein(VLDL) was detected by enzyme-linked immunosorbent assay(ELISA). Alanine aminotransferase(ALT) and aspartate ami-notransferase(AST) were determined by the Reitman-Frankel assay. The pathological changes in the liver were observed by hematoxylin-eosin(HE) staining and oil red O staining. Real-time fluorescence-based quantitative polymerase chain reaction(real-time PCR) and Western blot were adopted to detect the mRNA and protein expression of forkhead transcription factor O1(FoxO1), microsomal triglyceride transfer protein(MTP), and apolipoprotein B(APOB) in the liver. The results showed that high-dose ZGJTQG could signi-ficantly reduce the FBG and FINS levels(P<0.05, P<0.01), improve glucose tolerance and insulin resistance(P<0.05, P<0.01), alleviate the liver damage caused by HFD which was reflected in improving liver steatosis, and reduce the serum levels of TC, TG, LDL, VLDL, ALT, and AST(P<0.05, P<0.01) in T2DM mice combined with NAFLD. The findings also revealed that the mRNA and protein expression of FoxO1, MTP, and APOB in the liver was significantly down-regulated after the intervention of high-dose ZGJTQG(P<0.05, P<0.01). The above study showed that ZGJTQG could effectively improve glucolipid metabolism in T2DM combined with NAFLD, and the mechanism was closely related to the regulation of the FoxO1/MTP/APOB signaling pathway.

FoxO1/NLRP3 Inflammasome Promotes Age-Related Alveolar Bone Resorption

Periodontitis is the utmost common chronic oral disease that exhibits intense susceptibility to aging. Aging is characterized by persistent sterile low-grade inflammation, leading to age-related periodontal complications represented by alveolar bone loss. Currently, forkhead transcription factor O1 (FoxO1) is generally believed to have a significant role in body development, senescence, cell viability, and oxidative stress in numerous organs and cells. However, the role of this transcription factor in mediating age-related alveolar bone resorption has not been examined. In this study, FoxO1 deficiency was discovered to have a beneficial correlation with halting the progression of alveolar bone resorption in aged mice. To further investigate the function of FoxO1 in age-related alveolar bone resorption, osteoblastic-specific FoxO1 knockout mice were generated, leading to an amelioration in alveolar bone loss compared to aged-matched wild-type mice, manifested as enhanced osteogenic potential. Mechanistically, we identified enhancement of the NLRP3 inflammasome signaling in FoxO1-deficient osteoblasts in the high dose of reactive oxygen species. Concordant with our study, MCC950, a specific inhibitor of NLRP3 inflammasome, greatly rescued osteoblast differentiation under oxidative stress. Our data shed light on the manifestations of FoxO1 depletion in osteoblasts and propose a possible mechanism for the therapy of age-related alveolar bone loss.

Glycophagy mediated glucose-induced changes of hepatic glycogen metabolism via OGT1-AKT1-FOXO1Ser238 pathway

Glycophagy is the autophagy degradation of glycogen. However, the regulatory mechanisms for glycophagy and glucose metabolism remain unexplored. Herein, we demonstrated that high-carbohydrate diet (HCD) and high glucose (HG) incubation induced glycogen accumulation, protein kinase B (AKT)1 expression and AKT1-dependent phosphorylation of forkhead transcription factor O1 (FOXO1) at Ser238 in the liver tissues and hepatocytes. The glucose-induced FOXO1 phosphorylation at Ser238 prevents FOXO1 entry into the nucleus and the recruitment to the GABA(A) receptor-associated protein like 1 (gabarapl1) promoter, reduces the gabarapl1 promoter activity, and inhibits glycophagy and glucose production. The glucose-dependent O-GlcNAcylation of AKT1 by O-GlcNAc transferase (OGT1) enhances the stability of AKT1 protein and promotes its binding with FOXO1. Moreover, the glycosylation of AKT1 is crucial for promoting FOXO1 nuclear translocation and inhibiting glycophagy. Our studies elucidate a novel mechanism for glycophagy inhibition by high carbohydrate and glucose via OGT1-AKT1-FOXO1Ser238 pathway in the liver tissues and hepatocytes, which provides critical insights into potential intervention strategies for glycogen storage disorders in vertebrates, as well as human beings.

Lncrna CASC11 aggravates diabetic nephropathy via targeting FoxO1.

To explore the biological effects of CASC11 on aggravating diabetic nephropathy (DN) by regulating FoxO1 (forkhead transcription factor O1). Serum levels of CASC11 and FoxO1 in DN patients were detected. The possibility of CASC11 in predicting the onset of DN was analyzed by depicting ROC curves. Correlation between CASC11 and FoxO1 was evaluated by Pearson correlation test. After intervening CASC11 and FoxO1 levels, we found that changes in proliferative and migratory abilities in high glucose (HG)induced kidney mesangial cells were determined respectively. Protein levels of TGF-β1 and Smads regulated by both CASC11 and FoxO1 were examined by Western blot.

Detection value of FOXO1 gene methylation, blood glucose and lipids in patients with type 2 diabetic kidney disease.

Forkhead transcription factor O1 (FOXO1) methylation is associated with inflammation. Diabetic kidney disease (DKD) is characterized with increased inflammatory markers such as uric acid, hemogram indices, C-reactive protein derived markers, omentin and neuregulin. This study aimed to investigate the effect of DNA methylation in FOXO1 gene promoter, blood glucose and lipids in the process of type 2 DKD. Bisulfite genomic sequencing was used to monitor DNA methylation in the promoter region (+1021, +1193) of FOXO1 gene. The detections were taken in glycosylated hemoglobin A1c, fasting plasma glucose and blood lipid. 81 participants were divided into the control group, the preliminary diabetes mellitus group, the pure diabetes mellitus group, and the DKD group. The other groups displayed higher fasting plasma glucose than the control group (all P value < .05). The fasting plasma glucose level was higher in the pure diabetes mellitus group than the preliminary diabetes mellitus group (P = .004). The levels of HbA1c were higher in other groups than control group and preliminary diabetes mellitus groups (all P values < .01). The high-density lipoprotein level was lower in the DKD group (P = .021, P = .022) than control and pure diabetes mellitus group. The levels of low-density lipoprotein were statistically lower in preliminary diabetes mellitus and DKD groups than control group (all P value < .02). Along with the progress of DKD, a down trend was observed in the total methylation rate of FOXO1 gene (P = .025), which contains 5 CpG sites (1021, +1193) in the promoter. Hypomethylation in the promoter of FOXO1 gene, hyperglycemia and low level of serum lipid might be associated with the pathogenesis of type 2 DKD.

Wenshen Yangxue decoction promotes follicular development in aged female mice stimulation of the silent information regulator 3/forkhead transcription factor O1 3a pathway.

To primarily explore the effect and mechanism of Wenshen Yangxue decoction in promoting follicular development in elderly female mice. Fifty Institute of Cancer Research mice were randomly divided into blank, controlled ovarian hyperstimulation (COH), low-dose Wenshen Yangxue decoction, medium-dose Wenshen Yangxue decoction, and high-dose Wenshen Yangxue decoction groups, with 10 mice in each group. The number of ovulations, number of fertilizations, mitochondrial adenosine triphosphate (ATP) level, and mitochondrial DNA (mtDNA) of oocytes in each group were compared. Reverse transcription-polymerase chain reaction and Western blotting were used to detect the mRNA and protein expression levels of silent information regulator 3 (Sirt3) and forkhead transcription factor O1 3a (FOXO3a). Wenshen Yangxue decoction significantly increased the number of ovulations in mice (P < 0.05) and promoted the formation of fertilized eggs. The ATP level and mtDNA copy number of mice oocytes in the high-dose groups were significantly higher than those in the COH group (P < 0.05). Wenshen Yangxue decoction significantly increased the mRNA and protein levels of Sirt3 and FOXO3a in mouse oocytes. Wenshen Yangxue decoction promoted the development of follicles in elderly female mice, increased the number of ovulations and improved fertility. Its mechanism may be related to increased mitochondrial energy metabolism and regulation of the Sirt3/FOXO3a pathway.

1390-P: FOXO1 Promotes Sexually Dimorphic Effects on Energy Balance in the Preoptic Anterior Hypothalamus

The preoptic anterior hypothalamus (POAH) , known as a thermointegrative center, modulates metabolic adaptation in response to temperature change, thus making it relevant for body weight homeostasis. Forkhead transcription factor O1 (FoxO1) plays an important role in mediating effects of leptin and insulin on metabolic homeostasis in the hypothalamus. However, the homeostatic role of FoxO1 in POAH has not been investigated. We found that FoxO1 specific deletion in the POAH neurons (FoxO1POAH-KO) prevented high fat diet-induced obesity (DIO) in female but not male mice. This female-specific protection was associated with increased lean mass, decreased fat mass, and upregulated thermogenesis in adipose tissues. The female FoxO1POAH-KO mice also showed improved insulin sensitivity and increased energy expenditure when exposed at room temperature (22 °C) or cold (6 °C) . Moreover, the FoxO1POAH-KO-induced protection against DIO in females was blunted by ovariectomy (OVX) , while 17β-estradiol supplementation after OVX failed to restore this protection, suggesting an estrogen-independent mechanism. Finally, mice with FoxO1 constitutively activated in the POAH neurons (FoxO1POAH-CA) significantly increased DIO in both sexes, further supporting an essential metabolic role of FoxO1POAH. Together, these findings indicate that FoxO1POAH is a crucial transcription factor that directs and coordinates control of energy balance, thermogenesis, and glucose homeostasis in female mice. Key words: FoxO1, POAH, sex difference. Disclosure P. Luo: None. H. Ye: None. T. Unterman: None. P. Xu: None. Funding P. Xu is supported by National Institutes of Health (R00DK1070 and R01DK123098) , Department of Defense (Innovative Grant W81XWH-19-PRMRP-DA) , and The University of Chicago Diabetes Research and Training Center (The Pilot and Feasibility Award DK020595) .

Dietary fiber of Tartary buckwheat bran modified by steam explosion alleviates hyperglycemia and modulates gut microbiota in db/db mice

Type 2 diabetes is a serious threat to human health. Tartary buckwheat bran dietary fiber has good hypoglycemic activity, with its modification widely studied. However, the hypoglycemic activity of steam explosion modified Tartary buckwheat bran soluble dietary fiber (SE-SDF) has not been reported. This research aimed at investigating the hypoglycemic effect with its underlying mechanism of SE-SDF on type 2 diabetic db/db mice. Results found SE-SDF decreased the levels of fasting blood glucose and glycosylated hemoglobin while improved oral glucose tolerance, insulin resistance, and injuries of liver, pancreas, and colon in diabetic db/db mice. Additionally, SE-SDF up-regulated the protein expression levels of hepatic phosphatidylinositol 3 kinase (PI3K), G protein-coupled receptor43 (GPR43), and phospho-adenosine monophosphate activated protein kinase (p-AMPK), whereas inhibited the protein expression levels of hepatic fork-head transcription factor O1 (FoxO1), phosphoenolpyruvate carboxy kinase (PEPCK) and glucose-6-phosphatase (G-6-Pase). Moreover, SE-SDF increased the production of fecal short chain fatty acids (SCFAs) and the expression of colon GPR43 and the concentration of serum glucagon like peptide-1 (GLP-1), leading to reduced ratio of Firmicutes/Bacteroidetes but increased relative abundance of Parabacteroides, norank_f_Muribaculaceae, Alloprevotella, Ruminiclostridium_9, unclassified_f_Ruminococcaceae, and Lachnospiraceae_NK4A136_group. These findings suggested that SE-SDF ameliorated type 2 diabetes via activating the liver PI3K/Akt/FoxO1 and GPR43/AMPK signaling pathways and modulating the gut microbiota-SCFAs-GPR43/GLP-1 signaling axis.

Artemisinin Alleviates Cerebral Ischemia/Reperfusion Injury via Regulation of the Forkhead Transcription Factor O1 Signaling Pathway.

The effect and mechanism of artemisinin therapy on cerebral ischemia-reperfusion injury (CIRI) was analyzed in this work. 100 healthy male C57BL/6 mice were selected and randomly divided into the sham group (no treatment), CIRI model group (IR), IR + artemisinin posttreatment group (IR + Arte), EX527 + IR group (EX527 + IR), and EX527 + IR + artemisinin posttreatment group (EX527 + IR + Arte), with 20 mice in each group. The cerebral infarct volumes of mice in different groups were measured by the 2,3,5-triphenyltetrazolium chloride (TTC) staining method. The neurological function scores and oxidative stress levels of mice in different groups were measured and compared. In addition, the expressions of silent information regulator 1 (SIRT1), forkhead transcription factor O1 (FOXO1), and p53 protein in brain tissue were detected. The results showed that the contents of reactive oxygen species (ROS) and malondialdehyde (MDA) in the EX527 + IR group and EX527 + IR + Arte group were significantly higher than those in the IR + Arte group (P < 0.05). The expressions of SIRT1 protein in the brain tissue of the IR group and EX527 + IR group were much lower than that of the sham group (P < 0.01); compared with the IR + Arte group, the expression of the X527 + IR group in the brain tissue was greatly reduced (P < 0.05). The expression levels of FOXO1 protein and p53 protein in the brain tissue of mice in the IR group and EX527 + IR group were higher than those in the sham group (P < 0.01). It was concluded that artemisinin treatment can reduce oxidative stress damage and alleviate CIRI through the SIRT1/FOXO1 signaling pathway, thereby achieving neuroprotective effects.

Astragaloside IV protects against podocyte apoptosis by inhibiting oxidative stress via activating PPARγ-Klotho-FoxO1 axis in diabetic nephropathy

AimsPodocyte apoptosis plays an important role in the pathogenesis of diabetic nephropathy (DN). Astragaloside IV (AS-IV) has been shown to protect against podocyte apoptosis. Here we aim to investigate the mechanism responsible for the protective effects of AS-IV. Main methodsDiabetic db/db mice and high glucose (HG)-cultured podocytes were treated with AS-IV. Renal function and histopathological changes were measured to evaluate the therapeutic effects of AS-IV against DN. Adenovirus-mediated Klotho overexpression, Klotho siRNA, and PPARγ inhibitor were applied in vitro to investigate the potential mechanism. The expression levels of mRNA and proteins were analyzed by qRT-PCR, western blot or immunofluorescence. Intracellular ROS and mitochondrial superoxide were detected by DHE and MitoSOx Red, respectively. Cell apoptosis was evaluated by TUNEL staining and flow cytometry. Key findingsAS-IV improved renal function and ameliorated podocyte injury in db/db mice accompanied with enhanced Klotho expression in glomerular podocytes. In vitro, AS-IV inhibited HG-induced podocyte apoptosis and restored HG-inhibited Klotho expression, whereas Klotho knockdown abrogated the anti-apoptosis action of AS-IV. Further study showed that adenovirus-mediated Klotho overexpression enhanced Forkhead transcription factor O1 (FoxO1)-dependent antioxidant activity and attenuated HG-evoked oxidative stress and apoptosis. AS-IV prevented HG-induced FoxO1 inhibition and oxidative stress, whereas Klotho knockdown reversed these effects. Cotreatment with PPARγ inhibitor T0070907 abolished AS-IV-induced Klotho expression and anti-apoptosis action. SignificanceThese data suggested that AS-IV attenuated podocyte apoptosis presumably by inhibiting oxidative stress via activating PPARγ-Klotho-FoxO1 signaling pathway, thereby ameliorating DN. This study provided new insights into the molecular mechanisms of AS-IV against DN.

Lipocalin-2: a role in hepatic gluconeogenesis via AMP-activated protein kinase (AMPK).

Evidence is accumulating that lipocalin2 (LCN2) is implicated in insulin resistance and glucose homeostasis, but the underlying possible mechanisms remain unclear. This study is to investigate the possible linkage between LCN2 and AMP-activated protein kinase (AMPK) or forkhead transcription factor O1 (FoxO1), which influences insulin sensitivity and gluconeogenesis in liver. LCN2 knockout (LCN2KO) mice and wild-type littermates were used to evaluate the effect of LCN2 on insulin sensitivity and hepatic gluconeogenesis through pyruvate tolerance test (PTT), glucose tolerance test (ipGTT), insulin tolerance test (ITT), and hyperinsulinemic-euglycemic clamps, respectively. LCN2KO mice and WT mice in vivo, and in vitro HepG2 cells were co-transfected with adenoviral FoxO1-siRNA (Ad-FoxO1-siRNA) or adenovirus expressing constitutively active form of AMPK (Ad-CA-AMPK), or dominant negative adenovirus AMPK (Ad-DN-AMPK), the relative mRNA and protein levels of two key gluconeogenic enzymes phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6P) were measured. Improved insulin sensitivity and inhibited gluconeogenesis in the LCN2KO mice were confirmed by pyruvate tolerance tests and hyperinsulinemic-euglycemic clamps. Nuclear FoxO1 and its downstream genes PEECK and G6P were decreased in the livers of the LCN2KO mice, and AMPK activity was stimulated and directly phosphorylated FoxO1. In vitro, AMPK activity was inhibited in HepG2 cells overexpressing LCN2 leading to a decrease in phosphorylated FoxO1 and an increase in nuclear FoxO1. The present study demonstrates that LCN2 regulates insulin sensitivity and glucose metabolism through inhibiting AMPK activity, and regulating FoxO1 and its downstream genes PEPCK/G6P, which regulate hepatic gluconeogenesis.

Resveratrol attenuates dapagliflozin-induced renal gluconeogenesis via activating the PI3K/Akt pathway and suppressing the FoxO1 pathway in type 2 diabetes.

Dapagliflozin alleviates hyperglycemia by increasing glycosuria, but it induces renal gluconeogenesis, thus neutralizing its efficacy. Resveratrol (Rsv), a natural polyphenolic chemical, improves insulin sensitivity in type 2 diabetes (T2D). Here, we investigated the regulatory effects and underlying mechanisms of Rsv on dapagliflozin-induced renal gluconeogenesis. Male ob/ob mice were given the vehicle (HF), dapagliflozin (1 mg kg-1), Rsv (10 mg kg-1), or dapagliflozin and Rsv combination for 10 weeks. Glucose metabolism was evaluated by glucose and pyruvate tolerance tests. HK-2 cells (human renal proximal tubule cells) were treated with dapagliflozin (1 μmol L-1) for 2 h and further incubated with Rsv (10 μmol L-1) for 12 h. The effects of Rsv on gluconeogenesis and insulin signaling were assessed. Dapagliflozin treatment increased glucose production in HK-2 cells and lowered blood glucose and induced gluconeogenesis in ob/ob mice. After Rsv treatment, the enhanced glucose production and gluconeogenesis were alleviated. The upregulated mRNA and protein expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) and the activation of the forkhead transcription factor O1 (FoxO1) protein in the dapagliflozin group were attenuated by Rsv administration. Rsv also improved renal insulin signaling by increasing PI3K and Akt phosphorylation. The PI3K inhibitor LY294002 dramatically decreased the p-Akt expression and activated FoxO1 by dephosphorylation, thus diminishing the inhibitory effects of Rsv on dapagliflozin-induced PEPCK and G6Pase expression. The data showed the mechanisms of Rsv in attenuating dapagliflozin-induced renal gluconeogenesis via activating the PI3K/Akt pathway and further suppressing FoxO1 activation, suggesting a potential intervention to achieve better glucose-lowering effects for SGLT2 inhibitors in T2D therapy.

Forkhead transcription factor O1 (FoxO1) in torafugu pufferfish Takifugu rubripes: Molecular cloning, in vitro DNA binding, and target gene screening in fish metagenome.

The fish insulin/insulin-like growth factor (IGF) pathway has weak control over carbohydrate metabolism. To understand the molecular basis for the metabolic diversity, we characterized the forkhead box transcription factor O1A (FoxO1A), a downstream target of the insulin/IGF pathway, in torafugu Takifugu rubripes. The cloned torafugu FoxO1A cDNA contained all conserved features critical for its transcriptional activity and a unique unspliced intron encoding a poly-glutamine stretch. Torafugu FoxO1A showed the IGF-dependent nuclear exclusion and in vitro binding to the well-conserved FoxO1 binding site, DAF-16 binding element (DBE), but failed to bind to the insulin-responsive element by which mammalian FoxO1 mediates insulin effects. The subsequent in silico genomic screening provided a list of 587 potential torafugu FoxO1A target genes containing the DBE. Some carbohydrate metabolic genes regulated by FoxO1 in mammals were not included in the list. We further identified about 250 potential fish FoxO1 target genes by integrating results of the DBE screening against fish metagenome that contained 262 species. Neuronal processes appeared to be the common major function of fish FoxO1, although further annotation of the potential target genes is required. These results provide a part of the molecular basis underlying the weak association between the insulin/IGF pathway and carbohydrate metabolism in fish.

Up-regulation of CHMP4B alleviates microglial necroptosis induced by traumatic brain injury.

Microglial cells are key component of central nervous system (CNS) and mediate the immune response of the brain under physiological or pathological conditions. It tends to activate into a pro‐inflammatory M1 phenotype after traumatic brain injury (TBI) and promote secondary brain damage. Recently, necroptosis was found to promote microglial activation and neuroinflammation after TBI. However, the mechanism and specific interventions of microglial necroptosis after TBI remain poorly investigated. Here, we reported that overexpress the charged multivesicular body protein 4b (CHMP4B) which is a core member of the endosomal sorting required for transport complex III (ESCRT‐III) significantly decreased the level of necroptosis in microglia, improved neurological function recovery and protected against cell death after TBI. Further investigation showed that forkhead transcription factor O1 (FOXO1) was a crucial transcription factor that increased CHMP4B transcription by binding to the promoter region, thereby inhibiting necroptosis in microglia. Collectively, our findings demonstrated that CHMP4B relieved microglial necroptosis and neuroinflammation after TBI, and promote the recovery of nerve function. FOXO1 is an important factor in promoting CHMP4B expression. This study provides the novel viewpoint for TBI prevention and treatment.

Effect of electroacupuncture on silent information regulator 1, fork head transcription factor O1 and proopiomelanocortin in the hypothalamus of rats with obesity induced by high-fat diet

To investigate the effect of electroacupuncture (EA) on silent information regulator 1 (SIRT1), forkhead transcription factor O1 (FoxO1), and proopiomelanocortin (POMC) in the hypothalamus of rats with high-fat diet-induced obesity (DIO), as well as the mechanism of EA in regulating central appetite peptides to help lose weight. Male Wistar rats were randomly divided into normal group, model group, EA group, EA＋inhibitor group, inhibitor group, and sham-operation group, with 10 rats in each group. High-fat diet was used to establish a rat model of DIO. The rats in the EA group and EA＋inhibitor group were given EA at "Fenglong" (ST40), "Zhongwan "(CV12)，"Guanyuan "(CV4), and"Zusanli" (ST36) with continuous wave at a frequency of 2 Hz and an intensity of 1 mA, for 10 minutes each time. The rats in the EA＋inhibitor group and inhibitor group were given tube placement in the third ventricle and injection of the specific SIRT1 antagonist EX-527. The rats in the sham-operation group were given tube placement in the third ventricle and injection of artificial cerebrospinal fluid. The above treatment was given 3 times a week for 8 weeks in total. Body weight, food intake, and Lee's index were observed before and after treatment. An automatic biochemical analyzer was used to measure the serum levels of total cholesterol (TC), triglyceride (TG), and free fatty acid (FFA), and Western blot was used to measure the protein expression of SIRT1, FoxO1, acetylated FoxO1(AC-FoxO1), and POMC in the hypothalamus. Before treatment, the model group, the EA group, the EA＋inhibitor group, the inhibitor group, and the sham-operation group had significantly higher body weight and food intake than the normal group (P<0.01), and the model group and the sham-operation group had a significantly higher Lee's index than the normal group (P<0.05). Compared with the model group after treatment, the EA group and the EA＋inhibitor group had significant reductions in body weight, food intake, TC, and the protein expression of AC-FoxO1 (P<0.01, P<0.05) and significant increases in the protein expression of SIRT1, FoxO1 and POMC (P<0.01, P<0.05); the EA group had significant reductions in Lee's index and the levels of TG, FFA(P<0.05，P<0.01)；the inhibitor group had significant increases in food intake, the serum levels of TC, TG, FFA(P<0.01) and significant reductions in the protein expression of SIRT1, FoxO1 and POMC (P<0.01，P<0.05). Compared with the EA group, the EA＋inhibitor group and the inhibitor group had significant increases in body weight, food intake, Lee's index, the levels of TG, FFA and the protein expression of AC-FoxO1 (P<0.01, P<0.05) and significant reductions in the protein expression of SIRT1, FoxO1 and POMC (P<0.01); the inhibitor group had significant increases in the serum levels of TC (P<0.01). Compared with the EA＋inhibitor group, the inhibitor group had significant increases in body weight, food intake, the serum levels of TC, TG, FFA, and the protein expression of AC-FoxO1 (P<0.01), as well as significant reductions in the protein expression of SIRT1, FoxO1 and POMC (P<0.01). In rats with DIO, EA can effectively up-regulate the expression of SIRT1 in the hypothalamus, exert a deacetylation effect on FoxO1, and promote the expression of the downstream appetite-inhibiting peptide POMC, which may be one of the mechanisms of EA to help lose weight by regulating central appetite peptides in the obesity model.

Sweroside Alleviated LPS-Induced Inflammation via SIRT1 Mediating NF-κB and FOXO1 Signaling Pathways in RAW264.7 Cells.

Pterocephalus hookeri was used as a traditional Chinese medicine for the treatment of rheumatoid arthritis. Sweroside was a main iridoid isolated from P. hookeri. The present study aimed to investigate the anti-inflammatory effect mechanism of sweroside. In RAW264.7 cells induced by lipopolysaccharide (LPS), the abnormal proliferation, the NO content increase, and the downregulated Sirtuin1 (SIRT1) expression were observed. Sweroside could alleviate the inflammation by inhibiting cell proliferation through arresting the cell cycle at the G0/G1 phase, by suppressing pro-inflammatory cytokines and by promoting anti-inflammatory cytokines in LPS-induced RAW264.7 cells. Further mechanism research indicated that sweroside could activate the SIRT1, then suppress the nuclear factor-kappa B (NF-κB) and promote the Forkhead transcription factor O1 (FOXO1) signaling pathways. The present study indicated that sweroside may be the main anti-inflammatory constituent of P. hookeri and a promising candidate for anti-inflammation therapy.

Chitooligosaccharide Biguanide Repairs Islet β‐Cell Dysfunction by Activating the IRS‐2/PI3K/Akt Signaling Pathway in Type 2 Diabetic Rats

AbstractIslet β cell failure is a critical metabolic disorder in the development of type 2 diabetes (T2DM), and the decreased viability and dysfunction of β cells accelerate diabetic pathogenesis in association with higher mortality. In this study, the therapeutic effects of chitooligosaccharide biguanide (COSG), which is similar in structure to metformin and has negligible side effects, on islet β‐cell dysfunction and the possible mechanism are explored. Streptozocin‐induced diabetic rats are administered COSG via daily intragastric gavage for 8 weeks. COSG significantly controlled body weight loss, attenuated glucose levels in blood and urine, and increased serum insulin. Histological examination of the pancreas reveals that COSG also alleviated pancreatic atrophy in T2DM rats. Furthermore, COSG stimulated insulin receptor substrate‐2 (IRS‐2) signaling in rat islet β cells, thereby mediating the activation of the phosphatidylinositol 3 kinase/protein kinase (PI3K/Akt) signaling pathway. In addition, COSG promoted downstream forkhead transcription factor O1 (FoxO1) nuclear output to potentially activate pancreas duodenum homeobox‐1 (PDX‐1)/glucose transporter type‐2 (GLUT‐2)/glucose kinase (GCK) pathway‐regulated insulin secretion. COSG also inhibited the glycogen synthase kinase‐3β (GSK‐3β)/caspase‐3 pathway to prevent cell apoptosis. The intrinsic protective effects of COSG on the impaired insulin signaling system to delay β‐cell apoptosis, increase β‐cell growth and proliferation, improve β‐cell function and promote insulin secretion highlight the possibilities of COSG as a novel strategy for the prevention of T2DM.

Involvement of AMPK activation in the inhibition of hepatic gluconeogenesis by Ficus carica leaf extract in diabetic mice and HepG2 cells

The aim of this study was to explore the possible mechanisms of Ficus carica leaf (FCL) extract in suppressing hepatic gluconeogenesis in diabetic mice. Diabetic mice (streptozotocin-induced) received 1 g/kg of FCL extract twice a day for 6 weeks. Fasting blood glucose levels were measured and a 2-h oral glucose tolerance test was conducted. AMP-activated protein kinase (AMPK), phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G6Pase), and peroxisome proliferator activated receptor-γ coactivator-1α (PGC-1α) expression was examined. HepG2 hepatocytes were treated with FCL extract and an AMPK inhibitor (compound C) or agonist (AICAR), and PEPCK, G6pase, PGC-1α, AMPK, forkhead transcription factor O1 (FOXO1), and hepatic nuclear factor 4α (HNF4α) expression was determined. The results showed that FCL extract inhibited the expression of PEPCK and G6Pase in the liver of diabetic mice and HepG2 hepatocytes. FCL extract activated AMPK and decreased PGC-1α, HNF4α, and FOXO1 expression. The AMPK inhibitor attenuated those effects through inhibiting gluconeogenesis, while the AMPK agonist partially enhanced gluconeogenesis. In conclusion, FCL extract inhibits hepatic gluconeogenesis via activation of AMPK and down-regulation of gluconeogenic enzymes.

Forskolin Effect on FOXO1 Expression and Relationship of FOXO1 Activation to Oxidative Stress: From Molecular to Therapeutic Strategy

Background: Reactive Oxygen Species (ROS) production has been established as an essential contributor in the development cardiotoxicity. The increase of ROS production simultaneously leads to the inhibition of anti-oxidant systems. Forkhead transcription factor O1 (FOXO1) plays an important role in regulating metabolism and oxidant stress. Clozapine was used to induce cardiotoxicity. Forskolin the well-known anti-oxidant and anti-inflammatory agent was used to modulate the effect on both FOXO1 gene and its target gene catalase and to what extent it may protect against clozapine-induced cardiotoxicity. Methods: The animals were classified into: control group, forskolin group; forskolin was administered for 8 weeks; clozapine group, and forskolin + clozapine group; forskolin was pre-administered for 5 weeks then continued along with clozapine for the last 3 weeks. RT-qPCR and gel electrophoresis were done. We analyzed the relation between FoxO1 gene and oxidative stress. Results: These effects are achieved by the ability of Forskolin to modulate the expression of Foxo-1 and catalase, the levels of CKMB, troponin I, GST, MDA, and TNF- α, Caspase-3 were decreased, histopathological changes were improved. Forskolin reduce cardiomyocytes damage, and improve cardiac function by decreasing oxidative stress. Conclusion: Forkolin with its biological activities and anti-oxidative effects control cardiotoxicity induced by ROS in addition to its anti-inflammatory activity. This may be considered as therapy in cardiac problems management.