Transcription Factor Forkhead Box O1 Research Articles

Inhibition of FoxO1 alleviates polycystic ovarian syndrome by reducing inflammation and the immune response.

The aim of this study was to explore the role of forkhead box transcription Factor O1 (FoxO1) in chronic inflammation in polycystic ovary syndrome (PCOS). A PCOS rat model was constructed as an in vivo model by letrozole induction, and granulosa cells (GCs) from PCOS rats were isolated and cultured as an in vitro cellular model. FoxO1 was knocked down by shRNA and siRNA in the PCOS rat model and GCs model, respectively. H&E staining was conducted to evaluate the effect of FoxO1 inhibition on ovarian pathology and dysfunction in PCOS rats. The levels of inflammatory cytokines in the ovaries and uterus of PCOS rats and in GCs were assessed by ELISA. Flow cytometry was used to evaluate the changes in the contents of neutrophils and macrophages in the peripheral blood and spleen of PCOS rats. CCK-8 assays and Annexin V-FITC/PI staining were performed to evaluate the proliferation and apoptosis of GCs. The expression of genes and proteins related to the TLR4/NF-κB/NLRP3 pathway in GCs was determined by RT-qPCR and Western blotting. The results indicated that FoxO1 was highly expressed in PCOS rat model. Inhibition of FoxO1 significantly mitigated the pathological changes and dysfunction in the ovaries of PCOS rats while also suppressing inflammation and fibrosis in the ovaries and uterus. Moreover, knocking down FoxO1 facilitated the restoration of the normal ratio of neutrophils and macrophages in the peripheral blood and spleen of PCOS rats and promoted M2 polarization of macrophages. Additionally, inhibition of FoxO1 promoted the proliferation of GCs and inhibited the inflammatory response in GCs. Furthermore, FoxO1 knockdown inhibited the activation of the NF-κB pathway and the formation of the NLRP3 inflammasome in GCs. In conclusion, inhibition of FoxO1 can alleviate PCOS by inhibiting the TLR4/NF-κB/NLRP3 pathway to reduce inflammation and the immune response.

Angiotensin-(1-7) Improves Islet β-cell Dedifferentiation by Activating PI3K/Akt/FoxO1 Pathway.

Islet β-cell dedifferentiation may be the main cause of reduced insulin secretion. Angiotensin-(1-7) [Ang-(1-7)] can attenuate high glucose-induced apoptosis and dedifferentiation of pancreatic β-cell, but the specific signal transduction pathway and mechanism are not yet clear. This study aimed to investigate the effects of Ang-(1-7) on high glucose-induced islet β-cell dedifferentiation by activating the phosphatidylinositol-3-kinase/Protein kinase B/ Forkhead box transcription factor O1 (PI3K/Akt/FoxO1) signaling pathway. The mouse islet β-cell line MIN6 cells were passaged and cultured and randomly divided into five groups: control (Con) group, high glucose (HG) group, HG with Ang-(1-7) group, HG with Ang-(1-7) and specific MasR antagonist A-779 group, and HG with Ang-(1-7) and PI3K inhibitor LY294002 group. After 48 hours, glucose-stimulated insulin secretion (GSIS) was detected by Enzyme-Linked Immunosorbent Assay (ELISA). The mRNA and protein expression levels of β-cell-specific factors (Pancreatic duodenal homeobox-1 (Pdx1), v-maf musculoaponeurotic fibrosarcoma oncogene homolog A(MafA)) and endocrine progenitor cell-specific factors (Octamer binding transcription factor 4(Oct4), Nanog) were measured by Real Time-PCR and Western blot. The factors of protein expression levels of PI3K/Akt/FoxO1 signaling pathway (Akt, p-Akt, Fox- O1, p-FoxO1) were determined by Western blot. We observed for the first time that high glucotoxicity can induce dedifferentiation of pancreatic islet β-cell, causing a decrease in insulin secretion levels and expression of Pdx1, MafA, p-- FoxO1, and p-Akt and an increase in expression of Oct4 and Nanog. After Ang-(1-7) intervention, insulin secretion levels and expression of Pdx1, MafA, p-FoxO1 and p-Akt were increased, and the levels of Oct4 and Nanog were reduced. However, A-779 and LY294002 could reverse this effect. During these processes, the total Akt and total FoxO1 expression did not change significantly. Ang-(1-7) may prevent high glucose-induced pathological dedifferentiation of pancreatic β-cell by activating the PI3K/Akt/FoxO1 signaling pathway.

Decreased HAT1 expression in granulosa cells disturbs oocyte meiosis during mouse ovarian aging

BackgroundWith advanced maternal age, abnormalities during oocyte meiosis increase significantly. Aneuploidy is an important reason for the reduction in the quality of aged oocytes. However, the molecular mechanism of aneuploidy in aged oocytes is far from understood. Histone acetyltransferase 1 (HAT1) has been reported to be essential for mammalian development and genome stability, and involved in multiple organ aging. Whether HAT1 is involved in ovarian aging and the detailed mechanisms remain to be elucidated.MethodsThe level of HAT1 in aged mice ovaries was detected by immunohistochemical and immunoblotting. To explore the function of HAT1 in the process of mouse oocyte maturation, we used Anacardic Acid (AA) and small interfering RNAs (siRNA) to culture cumulus-oocyte complexes (COCs) from ICR female mice in vitro and gathered statistics of germinal vesicle breakdown (GVBD), the first polar body extrusion (PBE), meiotic defects, aneuploidy, 2-cell embryos formation, and blastocyst formation rate. Moreover, the human granulosa cell (GC)-like line KGN cells were used to investigate the mechanisms of HAT1 in this progress.ResultsHAT1 was highly expressed in ovarian granulosa cells (GCs) from young mice and the expression of HAT1 was significantly decreased in aged GCs. AA and siRNAs mediated inhibition of HAT1 in GCs decreased the PBE rate, and increased meiotic defects and aneuploidy in oocytes. Further studies showed that HAT1 could acetylate Forkhead box transcription factor O1 (FoxO1), leading to the translocation of FoxO1 into the nucleus. Resultantly, the translocation of acetylated FoxO1 increased the expression of amphiregulin (AREG) in GCs, which plays a significant role in oocyte meiosis.ConclusionThe present study suggests that decreased expression of HAT1 in GCs is a potential reason corresponding to oocyte age-related meiotic defects and provides a potential therapeutic target for clinical intervention to reduce aneuploid oocytes.

Angiotensin (1-7) reverses glucose-induced islet β cell dedifferentiation by Wnt/β-catenin/FoxO1 signalling pathway.

Recent studies have shown that a decline in isletβ cells quality is due to β-cell dedifferentiation, not only β-cell apoptosis. Angiotensin (1-7) [Ang(1-7)] could attenuate high glucose-induced apoptosis and dedifferentiation of pancreaticβ cells by combining with MAS receptors. However, the mechanism of such action has not been elucidated. Recent studies have revealed that Wnt/β-catenin and forkhead box transcription factor O1 (FoxO1) are associated with β-cell dedifferentiation. Our study aims to explore whether the effects of Ang(1-7)on islet b cell dedifferentiation are mediated through the Wnt/β-catenin/FoxO1 pathway. Isletβ cells were divided into 6 groups: a control group, a high-glucose group, high glucose with Ang(1-7) group, high-glucose with Ang(1-7) and A779 group, high-glucose with angiotensin(1-7) and CHIR99021 group, and high-glucose with CHIR99021 group. A779 is a kind of MAS receptor antagonist that blocks the action of Ang(1-7), and CHIR99021 is a Wnt pathway activator. The morphology of pancreaticβ cells was observed in each group after 48 hours of intervention. β-cell insulin secretory function and expressions of relevant factors were measured. Compared with the control group, the cell morphology became degraded in the high-glucose group and the capability of insulin secretion was reduced. Meanwhile, the expressions of matureβ cells markers [pancreatic and duodenal homeobox 1 (Pdx1) and MAF BZIP transcription factor A (MafA)] were reduced, while the expressions of endocrine progenitor cells makers [octamer-binding transcription factor 4 (Oct4) and Nanog] were increased. The addition of CHIR99021 resulted in profound deep destruction ofβ cells compared with the high-glucose group. However, such changes were dramatically reversed following the treatment of Ang(1-7). The addition of A779 significantly inhibited the improvement caused by Ang(1-7). Ang(1-7) can effectively reverseβ cell dedifferentiation through Wnt/β-catenin/FoxO1 pathway. It might be a new strategy for preventing and treating diabetes.

Astrocytic FoxO1 in the hypothalamus regulates metabolic homeostasis by coordinating neuropeptide Y neuron activity.

The forkhead box transcription factor O1 (FoxO1) is expressed ubiquitously throughout the central nervous system, including in astrocytes, the most prevalent glial cell type in the brain. While the role of FoxO1 in hypothalamic neurons in controlling food intake and energy balance is well-established, the contribution of astrocytic FoxO1 in regulating energy homeostasis has not yet been determined. In the current study, we demonstrate the essential role of hypothalamic astrocytic FoxO1 in maintaining normal neuronal activity in the hypothalamus and whole-body glucose metabolism. Inhibition of FoxO1 function in hypothalamic astrocytes shifts the cellular metabolism from glycolysis to oxidative phosphorylation, enhancing astrocyte ATP production and release meanwhile decreasing astrocytic export of lactate. As a result, specific deletion of astrocytic FoxO1, particularly in the hypothalamus, causes a hyperactivation of hypothalamic neuropeptide Y neurons, which leads to an increase in acute feeding and impaired glucose regulation and ultimately results in diet-induced obesity and systemic glucose dyshomeostasis.

Foxo3 Knockdown Mediates Decline of Myod1 and Myog Reducing Myoblast Conversion to Myotubes.

Sarcopenia has a high prevalence among the aging population. Sarcopenia is of tremendous socioeconomic importance because it can lead to falls and hospitalization, subsequently increasing healthcare costs while limiting quality of life. In sarcopenic muscle fibers, the E3 ubiquitin ligase F-Box Protein 32 (Fbxo32) is expressed at substantially higher levels, driving ubiquitin-proteasomal muscle protein degradation. As one of the key regulators of muscular equilibrium, the transcription factor Forkhead Box O3 (FOXO3) can increase the expression of Fbxo32, making it a possible target for the regulation of this detrimental pathway. To test this hypothesis, murine C2C12 myoblasts were transduced with AAVs carrying a plasmid for four specific siRNAs against Foxo3. Successfully transduced myoblasts were selected via FACS cell sorting to establish single clone cell lines. Sorted myoblasts were further differentiated into myotubes and stained for myosin heavy chain (MHC) by immunofluorescence. The resulting area was calculated. Myotube contractions were induced by electrical stimulation and quantified. We found an increased Foxo3 expression in satellite cells in human skeletal muscle and an age-related increase in Foxo3 expression in older mice in silico. We established an in vitro AAV-mediated FOXO3 knockdown on protein level. Surprisingly, the myotubes with FOXO3 knockdown displayed a smaller myotube size and a lower number of nuclei per myotube compared to the control myotubes (AAV-transduced with a functionless control plasmid). During differentiation, a lower level of FOXO3 reduced the expression Fbxo32 within the first three days. Moreover, the expression of Myod1 and Myog via ATM and Tp53 was reduced. Functionally, the Foxo3 knockdown myotubes showed a higher contraction duration and time to peak. Early Foxo3 knockdown seems to terminate the initiation of differentiation due to lack of Myod1 expression, and mediates the inhibition of Myog. Subsequently, the myotube size is reduced and the excitability to electrical stimulation is altered.

FOXO1 orchestrates the intestinal homeostasis via neuronal signaling in group 3 innate lymphoid cells.

The neuro-immune regulation is associated with homeostasis of the intestine. Intestinal group 3 innate lymphoid cells (ILC3s) are tissue-resident lymphocytes whose functions are affected by the intestine niche. However, how a gut neuronal signal coordinates the immune response of ILC3s is largely unknown. Here, we found that cyclic adenosine monophosphate (cAMP) signaling exacerbated the inflammatory response and attenuated the expression level of the transcription factor forkhead box O1 (FOXO1) in ILC3s. Deficiency of FOXO1 drove the hyperactivation of ILC3s and resulted in gut inflammation independently of T cells. Mechanistically, FOXO1 promoted the transcription of neuropeptide receptor VIPR2 and inhibited the transcription of adrenoceptor ADRA2A in ILC3s. FOXO1-related regulation of VIPR2 and ADRA2A signaling balanced the activation of ILC3s under steady condition or during colitis. Moreover, chronic stress elevated cAMP level and downregulated FOXO1 level, exacerbating intestinal inflammation. Our findings reveal that FOXO1 balances the activation of ILC3s via VIP and adrenergic signaling and regulates intestinal homeostasis.

Nicotinamide enhances natural killer cell function and yields remissions in patients with non-Hodgkin lymphoma.

Allogeneic natural killer (NK) cell adoptive transfer has shown the potential to induce remissions in relapsed or refractory leukemias and lymphomas, but strategies to enhance NK cell survival and function are needed to improve clinical efficacy. Here, we demonstrated that NK cells cultured ex vivo with interleukin-15 (IL-15) and nicotinamide (NAM) exhibited stable induction of l-selectin (CD62L), a lymphocyte adhesion molecule important for lymph node homing. High frequencies of CD62L were associated with elevated transcription factor forkhead box O1 (FOXO1), and NAM promoted the stability of FOXO1 by preventing proteasomal degradation. NK cells cultured with NAM exhibited metabolic changes associated with elevated glucose flux and protection against oxidative stress. NK cells incubated with NAM also displayed enhanced cytotoxicity and inflammatory cytokine production and preferentially persisted in xenogeneic adoptive transfer experiments. We also conducted a first-in-human phase 1 clinical trial testing adoptive transfer of NK cells expanded ex vivo with IL-15 and NAM (GDA-201) combined with monoclonal antibodies in patients with relapsed or refractory non-Hodgkin lymphoma (NHL) and multiple myeloma (MM) (NCT03019666). Cellular therapy with GDA-201 and rituximab was well tolerated and yielded an overall response rate of 74% in 19 patients with advanced NHL. Thirteen patients had a complete response, and 1 patient had a partial response. GDA-201 cells were detected for up to 14 days in blood, bone marrow, and tumor tissues and maintained a favorable metabolic profile. The safety and efficacy of GDA-201 in this study support further development as a cancer therapy.

FOXO3 Deficiency in Neutrophils Drives Colonic Inflammation and Tumorigenesis.

Inflammatory bowel disease (IBD), characterized by infiltration of polymorphonuclear neutrophils (PMNs), increases the risk of colon cancer. PMN activation corresponds to the accumulation of intracellular Lipid Droplets (LDs). As increased LDs are negatively regulated by transcription factor Forkhead Box O3 (FOXO3), we aim to determine the significance of this regulatory network in PMN-mediated IBD and tumorigenesis. Affected tissue of IBD and colon cancer patients, colonic and infiltrated immune cells, have increased LDs' coat protein, PLIN2. Mouse peritoneal PMNs with stimulated LDs and FOXO3 deficiency have elevated transmigratory activity. Transcriptomic analysis of these FOXO3-deficient PMNs showed differentially expressed genes (DEGs; FDR < 0.05) involved in metabolism, inflammation, and tumorigenesis. Upstream regulators of these DEGs, similar to colonic inflammation and dysplasia in mice, were linked to IBD and human colon cancer. Additionally, a transcriptional signature representing FOXO3-deficient PMNs (PMN-FOXO3389) separated transcriptomes of affected tissue in IBD (p = 0.00018) and colon cancer (p = 0.0037) from control. Increased PMN-FOXO3389 presence predicted colon cancer invasion (lymphovascular p = 0.015; vascular p = 0.046; perineural p = 0.03) and poor survival. Validated DEGs from PMN-FOXO3389 (P2RX1, MGLL, MCAM, CDKN1A, RALBP1, CCPG1, PLA2G7) are involved in metabolism, inflammation, and tumorigenesis (p < 0.05). These findings highlight the significance of LDs and FOXO3-mediated PMN functions that promote colonic pathobiology.

Transcription Factor Forkhead Box O1 Mediates Transforming Growth Factor-β1–Induced Apoptosis in Hepatocytes

Dysregulation of hepatocyte apoptosis is associated with several types of chronic liver diseases. Transforming growth factor-β1 (TGF-β1) is a well-known pro-apoptotic factor in the liver, which is constituted by a receptor complex composed of TGF-β receptor I and II, along with transcription factor Smad proteins. As a member of the forkhead box O (Foxo) class of transcription factors, Foxo1 is a predominant regulator of hepatic glucose production and apoptosis. In this study, we investigated the potential relationship between TGF-β1 signaling and Foxo1 in control of apoptosis in hepatocytes. By using hepatocytes isolated from both wild-type and liver-specific Foxo1 knockout mice, we found that TGF-β1 induces hepatocyte apoptosis in a Foxo1-dependent manner. We further demonstrated that TGF-β1 activates protein kinase A through TGF-β receptor I-Smad3, followed by phosphorylation of Foxo1 at Ser273 in promotion of apoptosis in hepatocytes. Moreover, Smad3 overexpression in the liver of mice promoted the levels of phosphorylated Foxo1-S273, total Foxo1, and a Foxo1-target pro-apoptotic gene Bim, which eventually resulted in hepatocyte apoptosis. We further demonstrated a crucial role of Foxo1-S273 phosphorylation in the pro-apoptotic effect of TGF-β1 by using hepatocytes isolated from Foxo1-S273A/A knock-in mice, in which the phosphorylation of Foxo1-S273 is disrupted. Taken together, we established a novel role of TGF-β1→protein kinase A→Foxo1 signaling cascades in control of hepatocyte survival.

Role of miR-300-3p in Leydig cell function and differentiation: A therapeutic target for obesity-related testosterone deficiency

MicroRNAs (miRNAs) regulate various cellular functions, but their specific roles in the regulation of Leydig cells (LCs) have yet to be fully understood. Here, we found that the expression of miR-300-3p varied significantly during the differentiation from progenitor LCs (PLCs) to adult LCs (ALCs). High expression of miR-300-3p in PLCs inhibited testosterone production and promoted PLC proliferation by targeting the steroidogenic factor-1 (Sf-1) and transcription factor forkhead box O1 (FoxO1) genes, respectively. As PLCs differentiated into ALCs, the miR-300-3p expression level significantly decreased, which promoted testosterone biosynthesis and suppressed proliferation of ALCs by upregulating SF-1 and FoxO1 expression. The LH/METTL3/SMURF2/SMAD2 cascade pathway controlled miR-300-3p expression, in which luteinizing hormone (LH) upregulated SMAD-specific E3 ubiquitin protein ligase 2 (SMURF2) expression through methyltransferase like 3 (METTL3)-mediated Smurf2 N6-methyladenosine modification. The Smurf2 then suppressed miR-300 transcription by inhibiting SMAD family member 2 (SMAD2) binding to the promoter of miR-300. Notably, miR-300-3p was associated with an obesity-related testosterone deficiency in men and the inhibition of miR-300-3p effectively rescued testosterone deficiency in obese mice. These findings suggested that miR-300-3p plays a pivotal role in LC differentiation and function, and could be a promising diagnostic or therapeutic target for obesity-related testosterone deficiency.

P16 INK4A drives nonalcoholic fatty liver disease phenotypes in high fat diet fed mice through biliary E2F1/FOXO1/IGF-1 signaling.

NAFLD is characterized by steatosis, hepatic inflammation, and fibrosis, which can develop into NASH. Patients with NAFLD/NASH have increased ductular reaction (DR) and biliary senescence. High fat/high cholesterol diet feeding increases biliary senescence, DR, and biliary insulin-like growth factor-1 (IGF-1) expression in mice. p16/IGF-1 converges with fork-head box transcription factor O1 (FOXO1) through E2F1. We evaluated p16 inhibition on NAFLD phenotypes and biliary E2F1/FOXO1/IGF-1 signaling. 4-week wild-type (C57BL/6J) male mice were fed a control diet (CD) or high fat/high cholesterol diet and received either p16 or control Vivo Morpholino (VM) by tail vein injection 2× during the 16th week of feeding. We confirmed p16 knockdown and examined: (i) NAFLD phenotypes; (ii) DR and biliary senescence; (iii) serum metabolites; and (iv) biliary E2F1/FOXO1/IGF-1 signaling. Human normal, NAFLD, and NASH liver samples and isolated cholangiocytes treated with control or p16 VM were evaluated for p16/E2F1/FOXO1/IGF-1 signaling. p16 VM treatment reduced cholangiocyte and hepatocyte p16. In wild-type high fat/high cholesterol diet mice with control VM, there were increased (i) NAFLD phenotypes; (ii) DR and biliary senescence; (iii) serum metabolites; and (iv) biliary E2F1/FOXO1/IGF-1 signaling; however, p16 VM treatment reduced these parameters. Biliary E2F1/FOX-O1/IGF-1 signaling increased in human NAFLD/NASH but was blocked by p16 VM. In vitro , p16 VM reduced biliary E2f1 and Foxo1 transcription by inhibiting RNA pol II binding and E2F1 binding at the Foxo1 locus, respectively. Inhibition of E2F1 reduced biliary FOXO1 in vitro. Attenuating hepatic p16 expression may be a therapeutic approach for improving NAFLD/NASH phenotypes.

Xanthosine, a purine glycoside mediates hepatic glucose homeostasis through inhibition of gluconeogenesis and activation of glycogenesis via regulating the AMPK/ FoxO1/AKT/GSK3β signaling cascade

Type 2 Diabetes Mellitus (T2DM) is characterized by hepatic insulin resistance, which results in increased glucose production and reduced glycogen storage in the liver. There is no previous study in the literature that has explored the role of Xanthosine in hepatic insulin resistance. Moreover, mechanistic explanation for the beneficial effects of Xanthosine in lowering glucose production in diabetes is yet to be determined. This study for the first time investigated the beneficial effects of Tribulus terrestris (TT) and its active constituent, Xanthosine on gluconeogenesis and glycogenesis in Free Fatty Acid (FFA)-induced CC1 hepatocytes and streptozotocin (STZ)-induced Wistar rats. Xanthosine enhanced glucose uptake and decreased glucose production through phosphorylation of AMP-activated protein kinase (AMPK) and forkhead box transcription factor O1 (FoxO1), and downregulation of two rate limiting enzymes of gluconeogenesis, phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) expression in FFA-induced CC1 cells. Xanthosine also prevented FFA-induced decreases in the phosphorylation of AKT/Protein kinase B, glycogen synthase kinase-3β (GSK3β), and increased glycogen synthase (GS) phosphorylation to increase the glycogen content in the hepatocytes. Moreover, in STZ-induced diabetic rats, oral administration of TT n-butanol fraction (TTBF) enriched with compound Xanthosine (10, 50 & 100 mg/kg body weight) improved insulin sensitivity, reduced fasting blood glucose levels, improved glucose homeostasis by reducing gluconeogenesis via AMPK/FoxO1-mediated PEPCK and G6Pase down-regulation and increasing glycogenesis via AKT/GSK3β-mediated GS activation. Overall, Xanthosine may be developed further for treating insulin resistance and hyperglycemia in T2DM.

Salvianolic Acid B Inhibits Oxidative Stress in Glomerular Mesangial Cells Alleviating Diabetic Nephropathy by Regulating SIRT3/FOXO1 Signaling

Introduction: Oxidative stress is pivotal in advancing diabetic nephropathy (DN). Salvianolic acid B (SAB), derived from Radix Salviae miltiorrhizae, exhibits renoprotective effects. However, the mechanisms underlying its action in DN are not fully elucidated. This study explores SAB’s protective effect on DN, focusing on its antioxidative properties in glomerular mesangial cells. Methods: The renoprotective effects of various SAB dosages on DN rats were assessed by evaluating kidney tissue pathological alterations through hematoxylin and eosin, periodic acid-Schiff, Masson, TUNEL staining, and kidney function through biochemical detection. Cell counting kit-8 and lactate dehydrogenase cytotoxicity assays were utilized to evaluate the viability of high glucose (HG)-induced HBZY-1 cells treated with various SAB dosages. Oxidative stress and inflammation levels were measured using enzyme-linked immunosorbent assay kits. The Sirtuin 3 (SIRT3)/Forkhead box transcription factor O1 (FOXO1) pathway was examined through Western blot and immunohistochemistry. Results: SAB mitigated kidney histopathological alterations and function and cell apoptosis in DN rats at various dosages. It enhanced the activity of glutathione peroxidase and superoxide dismutase while decreasing reactive oxygen species and malondialdehyde levels both in vivo and in vitro. SAB also suppressed the levels of pro-inflammatory cytokines (IL-1β, IL-6, MCP-1, and TNF-α) and the expression of collagen IV and fibronectin in HG-induced HBZY-1 cells. Furthermore, SAB activated the SIRT3/FOXO1 signaling pathway. Conclusion: Our findings suggest that SAB may alleviate oxidative stress in DN both in vivo and in vitro, potentially through the activation of the SIRT3/FOXO1-mediated signaling pathway. This study provides initial insights into the possible antioxidative and renoprotective effects of SAB, indicating its potential utility as a therapeutic agent for DN.

Branched-chain amino acid modulation of lipid metabolism, gluconeogenesis, and inflammation in a finishing pig model: targeting leucine and valine.

Branched-chain amino acids (BCAAs) play a regulatory role in adipogenesis and energy balance. Therefore, this study aimed to investigate the impact of BCAA supplements, especially leucine (Leu) and valine (Val) supplementation, on lipid metabolism and related disorders in a finishing pig model. The results demonstrated that Leu (1%) and Val decreased serum as well as hepatic lipid accumulation. Moreover, metabolomics and lipidomics analyses revealed that Leu and Val markedly downregulated the level of various lipid species in the liver. This outcome may be explained by Leu and Val promoting cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/hormone-sensitive triglyceride lipase (HSL) signaling pathways. Leu and Val altered the fatty acid composition in distinct adipose tissues and decreased the levels of inflammatory factors. Additionally, they significantly decreased back fat thickness, and the results of the fatty acid profiles demonstrated that Leu and Val significantly increased the levels of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) while decreasing those of saturated fatty acids (SFAs), especially in back fat and abdominal fat. Besides, Leu and Val restored glucose homeostasis by suppressing gluconeogenesis through the serine/threonine protein kinase (AKT)/transcription factor forkhead box O1 (FOXO1) signaling pathway in the liver and back fat. In summary, these results suggest that Leu and Val may serve as key regulators for modulating lipid metabolism and steatosis.

Epstein-Barr Virus Regulates Endothelin-1 Expression through the ERK/FOXO1 Pathway in EBV-Associated Gastric Cancer.

Epstein-Barr virus-associated gastric carcinoma (EBVaGC) is one of the four subtypes of gastric carcinoma and its unique clinicopathological mechanism is unclear. Herein, the expression of endothelin-1 (ET-1) in EBVaGC was lower than of Epstein-Barr virus-negative gastric carcinoma (EBVnGC) and associated with a low frequency of lymph node metastasis of EBVaGC. Functional studies showed that the activation of ET-1/endothelin receptor type A (ETAR) axis could promote cell growth, migration, and antiapoptosis. The expression of the ET-1 gene was unrelated to methylation of its promoter region and miRNAs (-1, -125a, -125b). After being treated with MEK1/2 inhibitor (PD0325901), the inactivation of ERK1/2 pathway resulted in downregulation of ET-1 and forkhead box O1 (FOXO1) expression. Further, FOXO1 knockdown decreased the ET-1 expression. These findings indicated that ET-1 could be involved in development of gastric cancer and EBV could suppress the expression of ET-1 via the regulation of the transcription factor FOXO1 through the MAPK/ERK pathway. IMPORTANCE The relationship between Epstein-Barr virus and gastric cancer has been relatively clear. However, there are still many unresolved mechanisms of the virus in tumorigenesis. In recent years, activation of the endothelin-1 signaling axis has been found to play an important role in tumorigenesis, which is involved in tumor angiogenesis and epithelial-mesenchymal transition. EBV genes. In our study, we found that ET-1 was low-expressed in EBV-positive gastric cancer cells, which was due to the inhibition of ERK signaling by EBNA1 through the repression of FOXO1 expression. The low expression of ET-1 limits the proliferation, migration, and anti-apoptotic ability of tumor cells. These findings contribute to further understanding of the role of EBV in EBV-associated gastric cancer.

Protective mechanisms of loquat leaf extract and ursolic acid against diabetic pro-inflammation.

The pharmacological effectiveness of loquat leaf extract (LE) and its important component, ursolic acid (UA), in the treatment of diabetes mellitus, has been well established in traditional medicine; however, the mechanism underlying their action is still unclear. We evaluated the protective effects of LE and UA against hyperglycemia-induced advanced glycation end product (AGE) formations and hepatic pro-inflammation. Oral administration of UA and LE at a dose of 50mg/kg/day for 15days yielded no significant hypoglycemic effect in diabetic db/db mice. UA and LE suppressed hepatic oxidative stress and AGE formation in diabetic mice, and this was followed by the downregulated mitogen-activated protein kinase signaling and nuclear factor κ B (NF-κB) activity. To identify the molecular target of LE and UA, a docking simulation was performed, and this predicted UA to bind to liver kinase B1 (LKB1), an upstream of AMP-activated protein kinase (AMPK)/transcription factor forkhead box O3 (FOXO3) axis. UA reversed the high-glucose-induced downregulation of LKB1-AMPK1-FOXO3 activation and antioxidant gene transcription. These findings demonstrated the antioxidant and anti-inflammatory effects of UA and LE against hyperglycemia-induced hepatic inflammation. Furthermore, we speculate that the LKB1/AMPK/FOXO3 pathway is a potential target responsible for these beneficial effects of LE and UA.

The Essential Role of FoxO1 in the Regulation of Macrophage Function.

Macrophages are widely distributed in various tissues and organs. They not only participate in the regulation of innate and adaptive immune response, but also play an important role in tissue homeostasis. Dysregulation of macrophage function is closely related to the initiation, development and prognosis of multiple diseases, including infection and tumorigenesis. Forkhead box transcription factor O1 (FoxO1) is an important member among the forkhead box transcription factor family. Through directly binding to the promoter regions of downstream target genes, FoxO1 is implicated in cell proliferation, apoptosis, metabolic activities and other biological processes. In this review, we summarized the regulatory role of FoxO1 in macrophage phagocytosis, migration, differentiation and inflammatory activation. We also emphasized that macrophage reciprocally modulated FoxO1 activity via a post-translational modification (PTM) dominant manner.

Hepatic p53 is regulated by transcription factor FOXO1 and acutely controls glycogen homeostasis

The tumor suppressor p53 is involved in the adaptation of hepatic metabolism to nutrient availability. Acute deletion of p53 in the mouse liver affects hepatic glucose and triglyceride metabolism. However, long-term adaptations upon the loss of hepatic p53 and its transcriptional regulators are unknown. Here we show that short-term, but not chronic, liver-specific deletion of p53 in mice reduces liver glycogen levels, and we implicate the transcription factor forkhead box O1 protein (FOXO1) in the regulation of p53 and its target genes. We demonstrate that acute p53 deletion prevents glycogen accumulation upon refeeding, whereas a chronic loss of p53 associates with a compensational activation of the glycogen synthesis pathway. Moreover, we identify fasting-activated FOXO1 as a repressor of p53 transcription in hepatocytes. We show that this repression is relieved by inactivation of FOXO1 by insulin, which likely mediates the upregulation of p53 expression upon refeeding. Strikingly, we find that high-fat diet–induced insulin resistance with persistent FOXO1 activation not only blunted the regulation of p53 but also the induction of p53 target genes like p21 during fasting, indicating overlapping effects of both FOXO1 and p53 on target gene expression in a context-dependent manner. Thus, we conclude that p53 acutely controls glycogen storage in the liver and is linked to insulin signaling via FOXO1, which has important implications for our understanding of the hepatic adaptation to nutrient availability.

Over Expression of FOXO1 in Subcutaneous Fatty Tissue and its Response to Resistance Training in High Fat Diet and Type 2 Diabetic Rat

Objective: Forkhead box proteins and Forkhead box transcription factor O1 (FOXO1) in particular, mediate insulin signaling pathways and glucose homeostasis. This study aimed to compare FOXO1 expression in subcutaneous adipose (SA) tissue between obese rats with and without type 2 diabetes (T2D) and its response to resistance training in T2D.&#x0D; Materials and Methods: 21 male wistar rats (220±20 g) were obese by 6 weeks high fat diet (HFD) and randomly assigned to either non-diabetes (n=7) or two T2D groups (control and exercise groups, n=7 in each case). Fasting glucose, insulin, insulin resistance and FOXO1 expression were compared between non-diabetes and diabetes groups. All variables were also assigned after resistance training in the form of climbing a ladder (6 weeks/5 times weekly) in exercise compare with control groups. Data were compared by ANOVA, independent and paired t-test methods (P&lt;0.05).&#x0D; Results: Induction of diabetes resulted in significant increase in insulin resistance, glucose, and FOXO expression in SA tissue and a decrease in insulin compared to obese health rats (P&lt; 0.0001). A significant decrease in fasting insulin (P&lt; 0.0001), insulin resistance (P&lt; 0.0001) and FOXO1 expression in SA tissue (P&lt; 0.0001) and increase in insulin (P: 0.002) were observed by resistance training compared to control diabetes rats.&#x0D; Conclusion: Based on our results, improving insulin resistance and glucose in response to resistance training in obese diabetic rats may be rooted in decreased insulin expression following these exercises.