RESUMEN

Ripened pu-erh tea is known to have beneficial hypoglycemic properties. However, it remains unclear whether the bioactive peptides produced during fermentation are also related to hypoglycemic potential. This study aimed to identify hypoglycemic peptides in ripened pu-erh tea and to elucidate their bioactive mechanisms using physicochemical property prediction, molecular docking, molecular dynamics simulations, and cell experiments. Thirteen peptides were identified by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Among them, AADTDYRFS (AS-9) and AGDGTPYVR (AR-9) exhibited high α-glucosidase inhibitory activity, with half-maximal inhibitory concentration (IC50) values of 0.820 and 3.942 mg/mL, respectively. Molecular docking and dynamics simulations revealed that hydrogen bonding, hydrophobic interactions, and van der Waals forces assist peptides AS-9 and AR-9 in forming stable and tight complexes with α-glucosidase. An insulin-resistance (IR)-HepG2 cell model was established. AS-9 was non-toxic to IR-HepG2 cells and significantly increased the glucose consumption capacity, hexokinase, and pyruvate kinase activities of IR-HepG2 cells (p < 0.05). AS-9 alleviated glucose metabolism disorders and ameliorated IR by activating the IRS-1/PI3K/Akt signaling pathway and increasing the expression levels of MDM2, IRS-1, Akt, PI3K, GLUT4, and GSK3ß genes. In addition, no hemolysis of mice red blood cells red blood cells occurred at concentrations below 1 mg/mL. This work first explored hypoglycemic peptides in ripened pu-erh tea, providing novel insights for enhancing its functional value.

Asunto(s)

Inhibidores de Glicósido Hidrolasas , Hipoglucemiantes , Simulación del Acoplamiento Molecular , Péptidos , Té , Hipoglucemiantes/farmacología , Hipoglucemiantes/química , Animales , Té/química , Humanos , Células Hep G2 , Péptidos/química , Péptidos/farmacología , Inhibidores de Glicósido Hidrolasas/farmacología , Inhibidores de Glicósido Hidrolasas/química , Ratones , Simulación de Dinámica Molecular , Resistencia a la Insulina , Transducción de Señal/efectos de los fármacos , Proteínas Sustrato del Receptor de Insulina/metabolismo , Espectrometría de Masas en Tándem , alfa-Glucosidasas/metabolismo , Fermentación

RESUMEN

Insulin-like growth factor (IGF)-I mediates long-term activities that determine cell fate, including cell proliferation and differentiation. This study aimed to characterize the mechanisms by which IGF-I determines cell fate from the aspect of IGF-I signaling dynamics. In L6 myoblasts, myogenic differentiation proceeded under low IGF-I levels, whereas proliferation was enhanced under high levels. Mathematical and experimental analyses revealed that IGF-I signaling oscillated at low IGF-I levels but remained constant at high levels, suggesting that differences in IGF-I signaling dynamics determine cell fate. We previously reported that differential insulin receptor substrate (IRS)-1 levels generate a driving force for cell competition. Computational simulations and immunofluorescence analyses revealed that asynchronous IRS-1 protein oscillations were synchronized during myogenic processes through cell competition. Disturbances of cell competition impaired signaling synchronization and cell fusion, indicating that synchronization of IGF-I signaling oscillation is critical for myoblast cell fusion to form multinucleate myotubes.

Asunto(s)

Diferenciación Celular , Factor I del Crecimiento Similar a la Insulina , Mioblastos , Transducción de Señal , Factor I del Crecimiento Similar a la Insulina/metabolismo , Mioblastos/metabolismo , Mioblastos/citología , Animales , Línea Celular , Proliferación Celular , Desarrollo de Músculos , Proteínas Sustrato del Receptor de Insulina/metabolismo , Ratas , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/citología , Fusión Celular

RESUMEN

Fucoxanthin (Fx) has garnered significant interest due to its exceptional biological properties. However, its efficacy in enhancing food quality and human health is contingent upon the solubility of the compound in water and its physicochemical stability. Therefore, nanocarriers must be developed to enhance the stability and biocompatibility of Fx. In this study, oxidized paramylon and Fx self-assembled nanoparticles (Fx-OEP) were prepared via the anti-solvent method, with a loading rate of 82.47 % for Fx. The Fx-OEP exhibited robust storage and photostability. In vitro simulated digestion assays demonstrated that Fx-OEP effectively protected Fx from premature gastric release, while achieving a release efficiency of 72.17 % in the intestinal phase. Fx-OEP has the capacity to scavenge a range of reactive oxygen species (ROS) induced by cellular oxidative stress. Treatment with Fx-OEP resulted in a significant reduction in ROS accumulation in insulin-resistant HepG2 cells, which was attributed to the activation of the nuclear factor E2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) pathway. This, in turn, activated insulin receptor substrate 1/glucose transporter type 4 (IRS1/GLUT4), promoting cellular glucose absorption and utilization. These findings indicate the potential of self-assembled nanoparticles based on oxidized paramylon as a new type of nanocarrier for delivering hydrophobic substances.

Asunto(s)

Resistencia a la Insulina , Nanopartículas , Xantófilas , Humanos , Xantófilas/farmacología , Xantófilas/química , Nanopartículas/química , Células Hep G2 , Oxidación-Reducción , Especies Reactivas de Oxígeno/metabolismo , Portadores de Fármacos/química , Factor 2 Relacionado con NF-E2/metabolismo , Estrés Oxidativo/efectos de los fármacos , Hemo-Oxigenasa 1/metabolismo , Transportador de Glucosa de Tipo 4/metabolismo , Proteínas Sustrato del Receptor de Insulina/metabolismo , Liberación de Fármacos , Glucanos/química , Glucanos/farmacología

RESUMEN

Background: Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age and is closely associated with chronic low-grade inflammation and insulin resistance. To clarify the contribution of prepubertal weight gain to the development of insulin resistance in PCOS, we investigated the effects of early postnatal overfeeding on inflammatory and energy-sensing pathways as well as on markers of insulin signaling in the liver of the PCOS rat model. Methods: Obesity induced by overfeeding was achieved by reducing litter size, while the PCOS-like condition was developed by treatment with 5α-dihydrotestosterone (DHT). Western blot and qPCR were used to analyze the expression of pro-inflammatory transcription factors and cytokines, as well as markers of the energy sensing and insulin signaling pathways. Results: The results showed that hepatic insulin sensitivity was impaired only in DHT-treated rats raised in small litters, as evidenced by increased phosphorylation of IRS1 on Ser307 and decreased expression of total IRS1. Postnatal overfeeding stimulated JNK1 activation independent of hyperandrogenemia; nevertheless, the synergistic effect of both factors triggered NLRP3 activation and increased IL1ß expression in the small litter DHT-treated group. This pro-inflammatory state was accompanied by decreased activatory phosphorylation of AMPK and reduced levels of its protein targets. Conclusions: Overfeeding in the early postnatal period leads to a decrease in hepatic insulin sensitivity in the rat model of PCOS, which is associated with decreased activation of AMPK and stimulation of the hepatic NLRP3-IL1ß signaling pathway. Accordingly, the inhibition of NLRP3 activation could provide a basis for the development of new therapeutic strategies for the treatment of insulin resistance in women with PCOS.

Asunto(s)

Dihidrotestosterona , Modelos Animales de Enfermedad , Inflamación , Resistencia a la Insulina , Hígado , Hipernutrición , Síndrome del Ovario Poliquístico , Animales , Síndrome del Ovario Poliquístico/metabolismo , Síndrome del Ovario Poliquístico/inducido químicamente , Síndrome del Ovario Poliquístico/patología , Femenino , Ratas , Dihidrotestosterona/farmacología , Hígado/metabolismo , Hígado/efectos de los fármacos , Hígado/patología , Inflamación/metabolismo , Inflamación/patología , Hipernutrición/metabolismo , Hipernutrición/complicaciones , Ratas Wistar , Obesidad/metabolismo , Animales Recién Nacidos , Transducción de Señal/efectos de los fármacos , Proteínas Sustrato del Receptor de Insulina/metabolismo

RESUMEN

Fenitrothion (FNT) is a common organophosphorus pesticide that is widely used in both agricultural and domestic pest control. FNT has been frequently detected in various environmental media, including the human body, and is a notable contaminant. Epidemiological investigations have recently shown the implications of exposure to FNT in the incidence of various metabolic diseases, such as diabetes mellitus in humans, indicating that FNT may be a potential endocrine disruptor. However, the effects of FNT exposure on glucose homeostasis and their underlying mechanisms in model organisms remain largely unknown, which may limit our understanding of the health risks of FNT. In this study, FNT (4 5, 90, 180, and 4 50 µM) exposure model of rat hepatocytes (Buffalo Rat Liver, BRL cells) was established to investigate the effects and potential mechanisms of its toxicity on glucose metabolism. Several key processes of glucose metabolism were detected in this study. The results showed significantly increased glucose levels in the culture medium and decreased glycogen content in the FNT-exposed BRL cells. The results of quantitative real-time PCR and enzymology showed the abnormal expression of genes and activity/content of glucose metabolic enzymes involved in glucose metabolism, which might promote gluconeogenesis and inhibit glucose uptake, glycolysis, and glycogenesis. Furthermore, gluconeogenesis and glycolytic were carried out in the mitochondrial membrane. The abnormal of mitochondrial membrane potential may be a potential mechanism underlying FNT-induced glucose metabolism disorder. In addition, the mRNA and protein expression implicated that FNT may disrupt glucose metabolism by inhibiting the AMPKα and IRS1/PI3K/AKT signaling pathways. In conclusion, results provide in vitro evidence that FNT can cause glucose metabolism disorder, which emphasizes the potential health risks of exposure to FNT in inducing diabetes mellitus.

Asunto(s)

Proteínas Quinasas Activadas por AMP , Fenitrotión , Glucosa , Proteínas Sustrato del Receptor de Insulina , Fosfatidilinositol 3-Quinasas , Proteínas Proto-Oncogénicas c-akt , Transducción de Señal , Animales , Ratas , Fenitrotión/toxicidad , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas Sustrato del Receptor de Insulina/metabolismo , Transducción de Señal/efectos de los fármacos , Proteínas Quinasas Activadas por AMP/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Glucosa/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Trastornos del Metabolismo de la Glucosa/inducido químicamente , Trastornos del Metabolismo de la Glucosa/metabolismo , Insecticidas/toxicidad

RESUMEN

Prolonged strenuous exercise induces oxidative stress, leading to oxidative damage, skeletal muscle fatigue, and reduced exercise performance. The body compensates for oxidative stress through antioxidant actions, while related enzymes alone may not overcome excessive oxidative stress during prolonged strenuous exercise. Phycocyanin is an important antioxidant supplement derived from blue-green algae, which may be helpful in this type of situation. This study determined the effects of phycocyanin on exercise performance from prolonged strenuous exercise. Forty Sprague Dawley male rats were divided into 5 groups (n = 8 /group); Control group (C), Exercise group (E), and Exercise with supplement groups receiving low dose (Phycocyanin = 100 mg/kg BW; ELP) and high dose (Phycocyanin = 200 mg/kg BW; EHP) or vitamin C (Vitamin C = 200 mg/kg BW; VC). Phycocyanin was found to decrease oxidative damage markers, muscle fatigue, and muscle atrophy through the activated AKT/mTOR pathway. This was also found to have greater increases in antioxidants via Nrf2 signaling and increases ATP synthesis, GLUT4 transporters, and insulin signaling due to increased IRS-1/AKT signaling. In conclusion, phycocyanin was found to reduce oxidative damage and muscle atrophy, including an increase in insulin signaling in skeletal muscles leading to increased exercise performance in rats.

Asunto(s)

Músculo Esquelético , Factor 2 Relacionado con NF-E2 , Estrés Oxidativo , Ficocianina , Condicionamiento Físico Animal , Proteínas Proto-Oncogénicas c-akt , Ratas Sprague-Dawley , Transducción de Señal , Serina-Treonina Quinasas TOR , Animales , Estrés Oxidativo/efectos de los fármacos , Masculino , Factor 2 Relacionado con NF-E2/metabolismo , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Transducción de Señal/efectos de los fármacos , Ratas , Ficocianina/farmacología , Proteínas Sustrato del Receptor de Insulina/metabolismo , Fatiga Muscular/efectos de los fármacos , Antioxidantes/metabolismo , Antioxidantes/farmacología

RESUMEN

The pathophysiological effects of chronic heavy metal exposures on human health remains uncertain. In this study, we developed a novel chronic, low-dose exposure of Cadmium (CLEC) model using the hepatocellular cell lines, HepG2 and HUH7. We modulated cell culture conditions to mimic human normoglycemic (5.6 mM) and hyperglycemic (15 mM) states with concomitant cadmium (Cd) exposures for 24 weeks. CLEC cells undergo non-trivial alterations in glucose signaling and metabolic characteristics within our model. We observe elevated baseline reactive oxygen species (ROS) production and decreased 2-NBDG uptake indicative of glucose metabolic dysfunction. Additionally, induction of metallothionein (MT) expression, increased activation of Akt signaling (via phosphorylation) and reduced IRS-2 protein expression are observed in CLEC cells. Cell line specific changes are observed with HepG2 showing a much higher MT gene induction compared to HUH7 cell line which impacts glucose metabolic dysfunction. Hyperglycemic culture conditions (representing type II diabetes) significantly modulate CLEC effects on cells. In conclusion, pathophysiologically relevant models of chronic heavy metal exposures are urgently needed to gain an in-depth, mechanistic understanding of the long-term impacts of toxic metals (e.g., Cd) on human metabolic health.

Asunto(s)

Cadmio , Hiperglucemia , Insulina , Transducción de Señal , Humanos , Transducción de Señal/efectos de los fármacos , Insulina/metabolismo , Hiperglucemia/inducido químicamente , Hiperglucemia/metabolismo , Cadmio/toxicidad , Células Hep G2 , Especies Reactivas de Oxígeno/metabolismo , Metalotioneína/metabolismo , Metalotioneína/genética , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Relación Dosis-Respuesta a Droga , Glucosa/metabolismo , Proteínas Sustrato del Receptor de Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina/genética

RESUMEN

Background: Our previous studies indicated that anesthesia/surgery could aggravate cognitive impairment and tau pathology in female 5XFAD transgenic (Tg) mice. However, it is unknown whether there are sex differences in the susceptibility of developing postoperative cognitive dysfunction in 5XFAD Tg mice. Objective: In this study, we aim to determine whether anesthesia/surgery can have different effects on female and male 5XFAD Tg mice, and to explore the underpinning mechanisms. Methods: The mice received abdominal surgery under isoflurane anesthesia. Morris water maze was used to assess the cognitive function. Hippocampal levels of p-tau (AT8), p-IRS1 (Ser612), IRS1, p-GSK3ß (Tyr216), and p-GSK3ß (Ser9) at postoperative day 1 were evaluated by western blot assays. Results: Anesthesia/surgery exaggerated cognitive impairment and tau pathology in female, but not male 5XFAD Tg mice. The anesthesia/surgery led to elevated hippocampus protein levels of p-IRS1 (Ser612)/IRS1 ratio and p-GSK3ß (Tyr216) and reduced hippocampus protein levels of p-GSK3ß (Ser9) in female, but not male 5XFAD Tg mice. Conclusions: This study demonstrated that female 5XFAD Tg mice were more susceptible to anesthesia/surgery-induced cognitive deterioration and tau pathology aggravation, potentially due to female-specific brain insulin resistance.

Asunto(s)

Disfunción Cognitiva , Resistencia a la Insulina , Ratones Transgénicos , Proteínas tau , Animales , Femenino , Ratones , Resistencia a la Insulina/fisiología , Masculino , Proteínas tau/metabolismo , Proteínas tau/genética , Disfunción Cognitiva/metabolismo , Disfunción Cognitiva/genética , Encéfalo/metabolismo , Encéfalo/patología , Proteínas Sustrato del Receptor de Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina/genética , Hipocampo/metabolismo , Hipocampo/patología , Anestesia/efectos adversos , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Complicaciones Cognitivas Postoperatorias/metabolismo , Modelos Animales de Enfermedad , Factores Sexuales , Caracteres Sexuales , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/patología

RESUMEN

Because of the advent of genome-editing technology, gene knockout (KO) hamsters have become attractive research models for diverse diseases in humans. This study established a new KO model of diabetes by disrupting the insulin receptor substrate-2 (Irs2) gene in the golden (Syrian) hamster. Homozygous KO animals were born alive but with delayed postnatal growth until adulthood. They showed hyperglycemia, high HbA1c, and impaired glucose tolerance. However, they normally responded to insulin stimulation, unlike Irs2 KO mice, an obese type 2 diabetes (T2D) model. Consistent with this, Irs2 KO hamsters did not increase serum insulin levels upon glucose administration and showed ß-cell hypoplasia in their pancreas. Thus, our Irs2 KO hamster provide a unique T2D animal model that is distinct from the obese T2D models. This model may contribute to a better understanding of the pathophysiology of human non-obese T2D with ß-cell dysfunction, the most common type of T2D in East Asian countries, including Japan.

Asunto(s)

Diabetes Mellitus Tipo 2 , Proteínas Sustrato del Receptor de Insulina , Mesocricetus , Animales , Cricetinae , Humanos , Masculino , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/genética , Modelos Animales de Enfermedad , Técnicas de Inactivación de Genes , Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina/genética , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patología

RESUMEN

Polycystic ovary syndrome (PCOS) is an intricate endocrine disorder that targets millions of women globally. Recent research has drawn attention to its association with cognitive impairment and Alzheimer's disease (AD) risk, yet the exact mechanism remains elusive. This study aimed to explore the potential role of PCOS-associated insulin resistance (IR) and inflammation in linking PCOS to AD pathogenesis. It additionally investigated the therapeutic merits of pterostilbene (PTS) in ameliorating PCOS and associated cognitive deficits in comparison to metformin (MET). Rats were divided into five groups; vehicle group, PTS group [30 mg/kg, per os (p.o.) for 13 days], and the remaining three groups received letrozole (1 mg/kg, p.o. for 21 days) to represent the PCOS, PCOS + MET (300 mg/kg, p.o. for 13 days), and PCOS + PTS groups, respectively. Behavioral tests were conducted, along with a histopathological investigation of brains and ovaries. Assessment of serum hormonal profile and hippocampal IRS-1/PI3K/AKT/GSK-3ß insulin signaling pathway components were performed. PTS rats exhibited improved insulin sensitivity and hormonal profile, besides enhanced neurobehavioral tests performance and histopathological findings. These effects may be attributed to modulation of the IRS-1/PI3K/AKT/GSK-3ß pathway, reducing GSK-3ß activity, and mitigating Tau hyperphosphorylation and Aß accumulation in the brain. Likewise, PTS attenuated nuclear factor kappa B-mediated inflammation and reversed AChE elevation, suggesting multifaceted neuroprotective effects. Comparatively, PTS showed outcomes similar to those of MET in most parameters. The obtained findings validated that dysregulated insulin signaling in PCOS rats detrimentally affects cognitive function, which is halted by PTS, unveiling the potential of PTS as a novel therapy for PCOS and related cognitive deficits.

Asunto(s)

Disfunción Cognitiva , Glucógeno Sintasa Quinasa 3 beta , Proteínas Sustrato del Receptor de Insulina , Resistencia a la Insulina , Metformina , Fosfatidilinositol 3-Quinasas , Síndrome del Ovario Poliquístico , Proteínas Proto-Oncogénicas c-akt , Transducción de Señal , Estilbenos , Animales , Síndrome del Ovario Poliquístico/tratamiento farmacológico , Síndrome del Ovario Poliquístico/metabolismo , Femenino , Metformina/farmacología , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Disfunción Cognitiva/tratamiento farmacológico , Disfunción Cognitiva/metabolismo , Proteínas Sustrato del Receptor de Insulina/metabolismo , Ratas , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal/efectos de los fármacos , Estilbenos/farmacología , Fosfatidilinositol 3-Quinasas/metabolismo , Modelos Animales de Enfermedad , Hipoglucemiantes/farmacología , Ratas Wistar

RESUMEN

Plasma levels of branched-chain amino acids and their metabolites, the branched-chain ketoacids are increased in insulin resistance. Our previous studies showed that leucine and its metabolite KIC suppress insulin-stimulated glucose uptake in L6 myotubes along with the activation of the S6K1-IRS-1 pathway. Because other tissue and fiber types can be differentially regulated by KIC, we analyzed the effect of KIC gavage on whole-body insulin sensitivity and insulin signaling in vivo. We hypothesized that KIC gavage would reduce whole-body insulin sensitivity and increase S6K1-IRS-1 phosphorylation in various tissues and muscle fibers. Five-week-old male Sprague-Dawley rats were starved for 24 hours and then gavaged with 0.75ml/100g of water, leucine (22.3g/L) or KIC (30g/L) twice, ten minutes apart. They were then euthanized at different time points post-gavage (0.5-3h), and muscle, liver, and heart tissues were dissected. Other sets of gavaged animals underwent an insulin tolerance test. Phosphorylation (ph) of S6K1 (Thr389), S6 (Ser235/6) and IRS-1 (Ser612) was increased at 30 minutes post leucine gavage in skeletal muscles irrespective of fiber type. Ph-S6 (Ser235/6) was also increased in liver and heart 30 minutes after leucine gavage. KIC gavage increased ph-S6 (Ser235/6) in the liver. Neither Leucine nor KIC influenced whole-body insulin tolerance, nor ph-Akt (Ser473) in skeletal muscle and heart. BCKD-E1 α abundance was highest in the heart and liver, while ph-BCKD-E1 α (Ser293) was higher in the gastrocnemius and EDL compared to the soleus. Our data suggests that only leucine activates the S6K1-IRS-1 signaling axis in skeletal muscle, liver and heart, while KIC only does so in the liver. The effect of leucine and KIC on the S6K1-IRS-1 signaling pathway is uncoupled from whole-body insulin sensitivity. These results suggest that KIC and leucine may not induce insulin resistance, and the contributions of other tissues may regulate whole-body insulin sensitivity in response to leucine/KIC gavage.

Asunto(s)

Resistencia a la Insulina , Insulina , Cetoácidos , Leucina , Ratas Sprague-Dawley , Transducción de Señal , Animales , Masculino , Leucina/metabolismo , Leucina/farmacología , Transducción de Señal/efectos de los fármacos , Insulina/metabolismo , Insulina/sangre , Ratas , Fosforilación/efectos de los fármacos , Cetoácidos/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/efectos de los fármacos , Proteínas Sustrato del Receptor de Insulina/metabolismo , Hígado/metabolismo , Hígado/efectos de los fármacos , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/efectos de los fármacos

RESUMEN

The kinase domains of receptor tyrosine kinases (RTKs) are highly conserved, yet they are able to discriminate among potential substrates to selectively activate downstream signaling pathways. In this study, we tested the importance of catalytic domain specificity by creating two series of chimeric RTKs. In one set, the kinase domain of insulin-like growth factor I receptor (IGF1R) was replaced by the kinase domains from insulin receptor (IR), macrophage stimulating protein 1 receptor/Ron (Ron) or Src. In the other set of chimeras, the kinase domain of epidermal growth factor receptor (EGFR) was similarly replaced by the kinase domains of IR, Ron, or Src. We expressed the wild-type and chimeric forms of the receptors in mammalian cells. For some signaling events, such as recognition of IRS1, the identity of the tyrosine kinase catalytic domain did not appear to be crucial. In contrast, recognition of some sites, such as the C-terminal autophosphorylation sites on EGFR, did depend on the identity of the kinase domain. Our data also showed that ligand dependence was lost when the native kinase domains were replaced by Src, suggesting that the identity of the kinase domains could be important for proper receptor regulation. Overall, the results are consistent with the idea that the fidelity of RTK signaling depends on co-localization and targeting with substrates, as well as on the intrinsic specificity of the kinase domain.

Asunto(s)

Receptores ErbB , Proteínas Tirosina Quinasas Receptoras , Receptor IGF Tipo 1 , Humanos , Receptores ErbB/metabolismo , Receptor IGF Tipo 1/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Fosforilación , Transducción de Señal , Animales , Receptor de Insulina/metabolismo , Especificidad por Sustrato , Familia-src Quinasas/metabolismo , Dominio Catalítico , Dominios Proteicos , Células HEK293 , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Sustrato del Receptor de Insulina/metabolismo

RESUMEN

OBJECTIVE: To examine the associations of renin-angiotensin system (RAS) inhibitor use with postmortem brain insulin signaling and neuropathology. METHODS: Among Religious Orders Study participants, 150 deceased and autopsied older individuals (75 with diabetes matched to 75 without by age at death, sex, and education) had measurements of insulin receptor substrate-1 (IRS-1) and RAC-alpha serine/threonine protein kinase (AKT1) collected in the prefrontal cortex using ELISA and immunohistochemistry. Alzheimer's disease (AD), brain infarcts, and cerebral vessel pathology data were assessed by systematic neuropathologic evaluations. RAS inhibitor use was determined based on visual inspection of medication containers during study visits. The associations of RAS inhibitor use with brain insulin signaling measures and neuropathology were examined using adjusted regression analyses. RESULTS: Of the 90 RAS inhibitor users (54 with diabetes), 65 had used only angiotensin-converting enzyme inhibitors, 11 only angiotensin II receptor blockers, and 14 used both. RAS inhibitor use was associated with lower pT308AKT1/total AKT1, but not with pS307IRS-1/total IRS-1 or the density of cells stained positive for pS616 IRS-1. RAS inhibitor use was not associated with the level of global AD pathology or amyloid beta burden, but it was associated with a lower tau-neurofibrillary tangle density. Additionally, we found a significant interaction between diabetes and RAS inhibitors on tangle density. Furthermore, AKT1 phosphorylation partially mediated the association of RAS inhibitor use with tau tangle density. Lastly, RAS inhibitor use was associated with more atherosclerosis, but not with other cerebral blood vessel pathologies or cerebral infarcts. INTERPRETATION: Late-life RAS inhibitor use may be associated with lower brain AKT1 phosphorylation and fewer neurofibrillary tangles.

Asunto(s)

Inhibidores de la Enzima Convertidora de Angiotensina , Proteínas Sustrato del Receptor de Insulina , Insulina , Sistema Renina-Angiotensina , Transducción de Señal , Humanos , Masculino , Femenino , Anciano de 80 o más Años , Anciano , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Sistema Renina-Angiotensina/efectos de los fármacos , Sistema Renina-Angiotensina/fisiología , Proteínas Sustrato del Receptor de Insulina/metabolismo , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología , Insulina/metabolismo , Encéfalo/metabolismo , Encéfalo/patología , Encéfalo/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Antagonistas de Receptores de Angiotensina/farmacología

RESUMEN

Based on the insulin receptor substrate(IRS)/phosphoinositide 3-kinase(PI3K)/protein kinase B(Akt) pathway, the intervention effect of Yupingfeng Powder on type 2 diabetes mellitus(T2DM) rats was studied, and the potential mechanism of improving T2DM hepatic insulin resistance was explored. A T2DM rat model was established by feeding with high-fat and high-sugar feed combined with intraperitoneal injection of streptozotocin. Successfully modeled rats were selected and divided into a model group, a positive control group(MET), and a Yupingfeng Powder group. At the same time, a blank group was set up, and corresponding drugs were given by gavage. The model group and blank group were given an equal amount of physiological saline by gavage. During the experiment, body mass and fasting blood glucose were regularly measured, and glucose tolerance and insulin tolerance were measured at the end of the experiment. After the experiment, the levels of blood glucose, insulin, blood lipids, and related liver function indicators were measured; changes in liver pathological damage were observed, levels of liver monoamine oxidase were detected, and qRT-PCR was used to detect mRNA expression levels of IRS/PI3K/Akt pathway related genes. Compared with the model group, the Yupingfeng Powder group had an increase in body weight, a decrease in fasting blood glucose, fasting insulin, and steady-state model evaluation index, a decrease in the area under the curve of glucose tolerance and insulin tolerance tests, a decrease in serum total cholesterol, triglycerides, and low-density lipoprotein cholesterol content, and an increase in high-density lipoprotein cholesterol content. Compared with the model group, the Yupingfeng Powder group showed a decrease in liver monoamine oxidase levels, a decrease in serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and total bilirubin levels, and an increase in total protein and albumin levels. Hematoxylin-eosin(HE) staining showed a reduction in pathological liver cell damage. Compared with the model group, the Yupingfeng Powder group showed a significant increase in the mRNA expression levels of IRS1, PI3K, and Akt in the liver of rats, as well as a significant decrease in the mRNA expression levels of interleukin-6(IL-6) and tumor necrosis factor-α(TNF-α). This indicates that Yupingfeng Powder can regulate the IRS/PI3K/Akt signaling pathway and glucose and lipid metabolism disorders, increase insulin sensitivity, improve hepatic insulin resistance, and thus play a therapeutic role in T2DM.

Asunto(s)

Diabetes Mellitus Tipo 2 , Medicamentos Herbarios Chinos , Proteínas Sustrato del Receptor de Insulina , Resistencia a la Insulina , Hígado , Fosfatidilinositol 3-Quinasas , Polvos , Proteínas Proto-Oncogénicas c-akt , Transducción de Señal , Animales , Ratas , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas Proto-Oncogénicas c-akt/genética , Medicamentos Herbarios Chinos/farmacología , Medicamentos Herbarios Chinos/administración & dosificación , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Fosfatidilinositol 3-Quinasas/genética , Hígado/metabolismo , Hígado/efectos de los fármacos , Masculino , Proteínas Sustrato del Receptor de Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina/genética , Transducción de Señal/efectos de los fármacos , Ratas Sprague-Dawley , Glucemia/metabolismo , Insulina/metabolismo , Humanos

RESUMEN

BACKGROUND: The importance of N6-methyladenosine (m6A) modification in tumorigenesis and progression have been highlighted. This study aimed to investigate the modification of insulin receptor substrate 1 (IRS1) by m6A and its role in oral squamous cell carcinoma (OSCC). METHODS: Bioinformatics was employed to predict differential genes related to epithelial-mesenchymal transition (EMT) in OSCC. Seventeen pairs of OSCC and paracancerous tissue samples were collected. The impact of IRS1 on OSCC cell growth and EMT was evaluated. The fluctuations in IRS1 enrichment and the involvement of p53/Line-1 were investigated. RESULTS: IRS1 was highly expressed in OSCC. IRS1 silencing decreased OSCC cell proliferation and increased apoptosis. IRS1 silencing hindered EMT by regulating related markers. IRS1 silencing upregulated p53 and downregulated Line-1 ORF1p. The p53 inhibition reversed the effects of IRS1 silencing and induced EMT in OSCC cells. Furthermore, the m6A modification of IRS1 was increased in OSCC cells. IRS1 were positively regulated by the m6A regulators methyltransferase-like 14 (METTL14) and YTH domain-containing protein 1 (YTHDC1). IRS1 bound to YTHDC1, and YTHDC1 knockdown inhibited the IRS1 nuclear export. The obesity-associated protein (FTO) negatively regulated IRS1, and FTO overexpression reversed the IRS1-induced OSCC tumor growth. CONCLUSIONS: m6A methylation-mediated IRS1 regulated EMT in OSCC through p53/Line-1. These findings provide potential therapeutic strategies for managing OSCC.

Asunto(s)

Adenosina , Carcinoma de Células Escamosas , Proliferación Celular , Transición Epitelial-Mesenquimal , Proteínas Sustrato del Receptor de Insulina , Neoplasias de la Boca , Transducción de Señal , Proteína p53 Supresora de Tumor , Proteínas Sustrato del Receptor de Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina/genética , Humanos , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/genética , Neoplasias de la Boca/genética , Neoplasias de la Boca/metabolismo , Neoplasias de la Boca/patología , Adenosina/análogos & derivados , Adenosina/metabolismo , Línea Celular Tumoral , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Proliferación Celular/genética , Transición Epitelial-Mesenquimal/genética , Regulación Neoplásica de la Expresión Génica , Apoptosis/genética , Animales , Ratones , Ratones Desnudos

RESUMEN

Insulin receptor substrate (IRS) proteins are key mediators in insulin signaling pathway. In social insect lives, IRS proteins played important roles in caste differentiation and foraging, but there function in disease defenses such as active immunization has not been reported yet. To investigate the issue, we successfully suppressed the IRS gene 3 days after dsRNA injection. Suppressing IRS gene increased the contents of glucose, trehalose, glycogen, and triglyceride and decreased the content of pyruvate in termites, and led to the metabolic disorder of glucose and lipids. IRS suppressing significantly enhanced grooming behaviors of nestmates of fungus-contaminated termites and hence increased the conidial load in the guts of the nestmates. Additionally, IRS suppressing led to significant downregulation of the immune genes Gram-negative bacteria-binding protein2 (GNBP2) and termicin and upregulation of the apoptotic gene caspase8, and hence diminished antifungal activity of nestmates of fungus-contaminated termites. The above abnormal behavioral and physiological responses significantly decreased the survival rate of dsIRS-injected nestmates of the fungus-contaminated termites. These findings suggest that IRS is involved in regulation of active immunization in termites, providing a better understanding of the link between insulin signaling and the social immunity of termites.

Asunto(s)

Proteínas Sustrato del Receptor de Insulina , Isópteros , Animales , Isópteros/inmunología , Proteínas Sustrato del Receptor de Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética

RESUMEN

Rationale: Sepsis is a life-threatening organ dysfunction and lack of effective measures in the current. Exosomes from mesenchymal stem cells (MSCs) reported to alleviate inflammation during sepsis, and the preconditioning of MSCs could enhance their paracrine potential. Therefore, this study investigated whether exosomes secreted by lipopolysaccharide (LPS)-pretreated MSCs exert superior antiseptic effects, and explored the underlying molecular mechanisms. Methods: Exosomes were isolated and characterized from the supernatants of MSCs. The therapeutic efficacy of normal exosomes (Exo) and LPS-pretreated exosomes (LPS-Exo) were evaluated in terms of survival rates, inflammatory response, and organ damage in an LPS-induced sepsis model. Macrophages were stimulated with LPS and treated with Exo or LPS-Exo to confirm the results of the in vivo studies, and to explain the potential mechanisms. Results: LPS-Exo were shown to inhibit aberrant pro-inflammatory cytokines, prevent organ damages, and improve survival rates of the septic mice to a greater extent than Exo. In vitro, LPS-Exo significantly promoted the M2 polarization of macrophages exposed to inflammation. miRNA sequencing and qRT-PCR analysis identified the remarkable expression of miR-150-5p in LPS-Exo compared to that in Exo, and exosomal miR-150-5p was transferred into recipient macrophages and mediated macrophage polarization. Further investigation demonstrated that miR-150-5p targets Irs1 in recipient macrophages and subsequently modulates macrophage plasticity by down-regulating the PI3K/Akt/mTOR pathway. Conclusion: The current findings highly suggest that exosomes derived from LPS pre-conditioned MSCs represent a promising cell-free therapeutic method and highlight miR-150-5p as a novel molecular target for regulating immune hyperactivation during sepsis.

Asunto(s)

Exosomas , Proteínas Sustrato del Receptor de Insulina , Lipopolisacáridos , Macrófagos , Células Madre Mesenquimatosas , MicroARNs , Fosfatidilinositol 3-Quinasas , Proteínas Proto-Oncogénicas c-akt , Sepsis , Transducción de Señal , Serina-Treonina Quinasas TOR , MicroARNs/genética , MicroARNs/metabolismo , Animales , Exosomas/metabolismo , Células Madre Mesenquimatosas/metabolismo , Sepsis/metabolismo , Sepsis/inmunología , Serina-Treonina Quinasas TOR/metabolismo , Ratones , Proteínas Proto-Oncogénicas c-akt/metabolismo , Macrófagos/metabolismo , Macrófagos/inmunología , Proteínas Sustrato del Receptor de Insulina/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Masculino , Ratones Endogámicos C57BL , Activación de Macrófagos/efectos de los fármacos , Modelos Animales de Enfermedad

RESUMEN

Milk fat synthesis has garnered significant attention due to its influence on the quality of milk. Recently, an increasing amount of proofs have elucidated that microRNAs (miRNAs) are important post-transcriptional factor involved in regulating gene expression and play a significant role in milk fat synthesis. MiR-200a was differentially expressed in the mammary gland tissue of dairy cows during different lactation periods, which indicated that miR-200a was a candidate miRNA involved in regulating milk fat synthesis. In our research, we investigated the potential function of miR-200a in regulating milk fat biosynthesis in bovine mammary epithelial cells (BMECs). We discovered that miR-200a inhibited cellular triacylglycerol (TAG) synthesis and suppressed lipid droplet formation; at the same time, miR-200a overexpression suppressed the mRNA and protein expression of milk fat metabolism-related genes, such as fatty acid synthase (FASN), peroxisome proliferator-activated receptor gamma (PPARγ), sterol regulatory element-binding protein 1 (SREBP1), CCAAT enhancer binding protein alpha (CEBPα), etc. However, knocking down miR-200a displayed the opposite results. We uncovered that insulin receptor substrate 2 (IRS2) was a candidate target gene of miR-200a through the bioinformatics online program TargetScan. Subsequently, it was confirmed that miR-200a directly targeted the 3'-untranslated region (3'-UTR) of IRS2 via real-time fluorescence quantitative PCR (RT-qPCR), western blot analysis, and dual-luciferase reporter gene assay. Additionally, IRS2 knockdown in BMECs has similar effects to miR-200a overexpression. Our research set up the mechanism by which miR-200a interacted with IRS2 and discovered that miR-200a targeted IRS2 and modulated the activity of the PI3K/Akt signaling pathway, thereby taking part in regulating milk fat synthesis in BMECs. Our research results provided valuable information on the molecular mechanisms for enhancing milk quality from the view of miRNA-mRNA regulatory networks.

Asunto(s)

Células Epiteliales , Proteínas Sustrato del Receptor de Insulina , Glándulas Mamarias Animales , MicroARNs , Leche , Fosfatidilinositol 3-Quinasas , Proteínas Proto-Oncogénicas c-akt , Transducción de Señal , Animales , Bovinos/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Leche/metabolismo , Leche/química , Células Epiteliales/metabolismo , Femenino , Proteínas Sustrato del Receptor de Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina/genética , Glándulas Mamarias Animales/metabolismo , Glándulas Mamarias Animales/citología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas Proto-Oncogénicas c-akt/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Fosfatidilinositol 3-Quinasas/genética , Triglicéridos/metabolismo , Triglicéridos/biosíntesis , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/genética , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo , Grasas/metabolismo , Lactancia/genética

RESUMEN

Somatic mutations have been identified in 10% to 63% of focal cortical dysplasia type II samples, primarily linked to the mTOR pathway. When the causative genetic mutations are not identified, this opens the possibility of discovering new pathogenic genes or pathways that could be contributing to the condition. In our previous study, we identified a novel candidate pathogenic somatic variant of IRS-1 c.1791dupG in the brain tissue of a child with focal cortical dysplasia type II. This study further explored the variant's role in causing type II focal cortical dysplasia through in vitro overexpression in 293T and SH-SY5Y cells and in vivo evaluation via in utero electroporation in fetal brains, assessing effects on neuronal migration, morphology, and network integrity. It was found that the mutant IRS-1 variant led to hyperactivity of p-ERK, increased cell volume, and was predominantly associated with the MAPK signaling pathway. In vivo, the IRS-1 c.1791dupG variant induced abnormal neuron migration, cytomegaly, and network hyperexcitability. Notably, the ERK inhibitor GDC-0994, rather than the mTOR inhibitor rapamycin, effectively rescued the neuronal defects. This study directly highlighted the ERK signaling pathway's role in the pathogenesis of focal cortical dysplasia II and provided a new therapeutic target for cases of focal cortical dysplasia II that are not treatable by rapamycin analogs.

Asunto(s)

Proteínas Sustrato del Receptor de Insulina , Sistema de Señalización de MAP Quinasas , Mutación , Humanos , Proteínas Sustrato del Receptor de Insulina/genética , Proteínas Sustrato del Receptor de Insulina/metabolismo , Sistema de Señalización de MAP Quinasas/genética , Animales , Malformaciones del Desarrollo Cortical de Grupo I/genética , Malformaciones del Desarrollo Cortical de Grupo I/metabolismo , Encéfalo/metabolismo , Encéfalo/patología , Neuronas/metabolismo , Neuronas/patología , Movimiento Celular/genética , Células HEK293 , Femenino , Displasia Cortical Focal , Epilepsia

RESUMEN

Nucleotides (NTs) act as pivotal regulatory factors in numerous biological processes, playing indispensable roles in growth, development, and metabolism across organisms. This study delves into the effects of exogenous NTs on hepatic insulin resistance using palmitic-acid-induced HepG2 cells, administering interventions at three distinct dosage levels of exogenous NTs. The findings underscore that exogenous NT intervention augments glucose consumption in HepG2 cells, modulates the expression of glycogen-synthesis-related enzymes (glycogen synthase kinase 3ß and glycogen synthase), and influences glycogen content. Additionally, it governs the expression levels of hepatic enzymes (hexokinase, phosphoenolpyruvate carboxykinase, and glucose-6-phosphatase). Moreover, exogenous NT intervention orchestrates insulin signaling pathway (insulin receptor substrate-1, protein kinase B, and forkhead box protein O1) and AMP-activated protein kinase (AMPK) activity in HepG2 cells. Furthermore, exogenous NT intervention fine-tunes the expression levels of oxidative stress-related markers (malondialdehyde, glutathione peroxidase, and NADPH oxidase 4) and the expression of inflammation-related nuclear transcription factor (NF-κB). Lastly, exogenous NT intervention regulates the expression levels of glucose transporter proteins (GLUTs). Consequently, exogenous NTs ameliorate insulin resistance in HepG2 cells by modulating the IRS-1/AKT/FOXO1 pathways and regulate glucose consumption, glycogen content, insulin signaling pathways, AMPK activity, oxidative stress, and inflammatory status.

Asunto(s)

Proteína Forkhead Box O1 , Proteínas Sustrato del Receptor de Insulina , Resistencia a la Insulina , Ácido Palmítico , Proteínas Proto-Oncogénicas c-akt , Transducción de Señal , Humanos , Células Hep G2 , Ácido Palmítico/farmacología , Proteínas Sustrato del Receptor de Insulina/metabolismo , Proteína Forkhead Box O1/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal/efectos de los fármacos , Nucleótidos/metabolismo , Nucleótidos/farmacología , Glucosa/metabolismo , Estrés Oxidativo/efectos de los fármacos , Glucógeno/metabolismo , Insulina/metabolismo