Hyperglycemia-Induced Oxidative-Nitrosative Stress Induces Inflammation and Neurodegeneration via Augmented Tuberous Sclerosis Complex-2 (TSC-2) Activation in Neuronal Cells

Inducing elevated glucose levels in vitro: A model to simulate prediabetes (preDBT) states in primary cultures

There is increasing evidence suggesting a relationship between prediabetes (preDBT, the early stage of Type 2 Diabetes or DBT2) and neurodegenerative disorders (NDDs) such as Alzheimer's disease. The preDBT stage, characterized by impaired fasting glucose (IFG), may represent an early risk factor for cognitive decline and the onset of NDDs. However, the underlying mechanisms connecting preDBT to cognitive impairment and neurodegeneration remain poorly understood. This study aims to explore the effects of IFG on central nervous system (CNS) cells by developing an in vitro model of preDBT using sera from individuals with IFG. Our results demonstrate that exposure of astrocyte-neuron mixed cultures to IFG sera induced hyperglycemia, increased oxidative levels and astrogliosis that would lead to cognitive impairment observed in the analyzed cohort, as evidenced by a battery of cognitive tests. These findings suggest that the early stages of preDBT may trigger changes in CNS cells that correlate with cognitive decline. The study underscores the importance of early diagnosis and intervention in preDBT to prevent progression to DBT2 and associated NDDs.

Analyzing the correlation between acute ischemic stroke and triglyceride-glucose index based on ordered logistic regression

Objective

To investigate the association between insulin resistance, measured by the triglyceride-glucose (TyG) index, and clinical outcomes in patients with acute ischemic stroke who underwent intravenous thrombolysis with alteplase.

Methods

This retrospective study included 165 patients with acute ischemic stroke treated with intravenous alteplase. Insulin resistance was evaluated using the TyG index, and its relationship with the modified Rankin Scale (mRS) scores was analyzed. The analysis was conducted using R software (version R 4.1.3) to evaluate the correlation between the TyG index and functional outcomes at 14, 30, and 90 days post-stroke.

Results

The study found that each unit increase in the TyG index significantly raised the risk of poor functional outcomes at 14 days (OR 9.86; 95% CI: 3.32-32.21; P < 0.001), 30 days (OR 5.82; 95% CI: 2.08-17.45; P = 0.001), and 90 days (OR 9.79; 95% CI: 3.33-31.66; P < 0.001) following a stroke. Higher TyG index values were associated with worse neurological outcomes. Although male gender, older age, and smoking were also linked to poorer outcomes, these associations did not reach statistical significance.

Conclusion

The findings suggest that a higher TyG index, indicating greater insulin resistance, is associated with worse neurological outcomes in stroke patients. Early intervention targeting insulin resistance may improve clinical outcomes in ischemic stroke patients, and further research is needed to explore additional factors affecting neurological recovery.

Jaranol alleviates cognitive impairment in db/db mice through the PI3K/AKT pathway

The widely used Radix Astragali (RA) has significant therapeutic effects on cognitive impairment (CI) caused by type 2 diabetes (T2DM). However, the effective active ingredients and the precise mechanism underly RA alleviation of T2DM-induced CI still require further study. In this study, we aim to elucidate whether and how jaranol, a key effective active ingredient in RA, influences CI in db/db mice. We used various online databases and Cytoscape to screen jaranol as the most active ingredient of RA in the treatment of T2DM-induced CI. The fear conditioning experiment, new object recognition (NOR) test, and Morris water maze (MWM) test were conducted to assess the improvement effect of jaranol on CI in diabetic mice. The protein-protein interaction (PPI) network, Cytoscape, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to identify key genes. The levels of AKT and caspase-3 were determined by Western blotting. The number of surviving hippocampal neurons was verified through Nissl staining. AutoDock was utilized for predicting potential binding sites between jaranol and key genes.As a result, jaranol attenuated CI in db/db mice probably through activation of PI3K-AKT signaling pathway by inhibiting cell apoptosis in hippocampus. Furthermore, A329 near the active site of AKT1 had hydrogen bond with jaranol. In conclusion, we suggest that jaranol may have therapeutic applications in T2DM-induced CI by targeting the PI3K-AKT signaling pathway directly via key sites. Our study provides alternative drugs and potential therapeutic targets for the prevention and treatment of T2DM-induced CI.

Risk factors of delirium after cardiac surgery: a systematic review and meta-analysis

BACKGROUND

Post-operative delirium (POD) is a relatively common occurrence following surgical procedures, particularly cardiac surgeries. Given that the majority of pharmacologic treatments for delirium have demonstrated inadequate efficacy, it is of great importance to identify risk factors to prevent delirium or reduce its complications. Consequently, in this systematic review and meta-analysis, we identified risk factors of POD after cardiac surgery.

METHOD

A comprehensive search of the literature was conducted using the databases Scopus, PubMed, and Web of Science from the inception to April 22, 2024. The objective was to identify prospective cohorts that had assessed the risk factors associated with POD in patients undergoing cardiac surgery using multivariate regression.

RESULTS

Of the 3,166 studies that were initially screened, 23 were included in the review. Nine risk factors were evaluated including age (OR 1.06, 95% CI (1.04, 1.08), p < 0.001), pre-operative depression (OR 3.71, 95% CI (2.45, 5.62), p < 0.001), post-operative atrial fibrillation (AF) (OR 2.39, 95% CI (1.79, 3.21), p < 0.001), hypertension (HTN) (OR 1.64, 95% CI (0.75, 3.56), p = 0.212), age ≥ 65 (OR 3.32, 95% CI (2.40, 4.60), p < 0.001), pre-operative AF (OR 4.43, 95% CI (2.56, 7.69), p < 0.001), diabetes mellitus (OR 2.16, 95% CI (1.39, 3.35), p = 0.001), combined coronary artery bypass graft (CABG) + valve surgery (OR 2.73, 95% CI (1.66, 4.49), p < 0.001), and cardiopulmonary bypass (CPB) time (OR 1.02, 95% CI (1.01, 1.04), p = 0.001).

CONCLUSIONS

A total of nine risk factors were evaluated, from which eight were found to have a statistically significant effect on the risk of developing POD. These factors can be employed to more effectively identify at-risk patients and to prevent the occurrence of POD. Furthermore, this approach can facilitate earlier diagnosis and more effective patient care.

Mesenchymal stem cells improve cardiac function in diabetic rats by reducing cardiac injury biomarkers and downregulating JAK/STAT/iNOS and iNOS/Apoptosis signaling pathways

Cardiovascular complications are prevalent manifestations of type 2 diabetes mellitus (T2DM) and are usually the main cause of death. This study aims to show the underlying mechanisms of the potential therapeutic effect of mesenchymal stem cells (MSCs) on diabetic cardiac dysfunction. Twenty-four male Wistar rats were randomly assigned to one of three groups The control group received standard laboratory chow, and the groups with T2DM received a single dose of 45 mg/kg body weight of streptozotocin (STZ) after 3 weeks of pretreatment with a high-fat diet (HFD). Eight weeks after the diagnosis of T2DM, rats were divided into two groups: the T2DM model group and the T2DM + MSCs group. BM-MSCs were administered systemically at 2 × 106 cells/rat doses. A Significant amelioration in Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) and dyslipidemia was noted 2 weeks post-administration of MSCs. Administration of MSCs improved dyslipidemia, the altered cardiac injury biomarkers (p ≤ 0.0001), downregulated Janus kinase 2/signal transducer and activator of transcription 3(JAK2/STAT3)/inducible Nitric oxide synthase (iNOS) and iNOS/Apoptosis signaling pathways. This was associated with improved cardiac dysfunction (impaired left ventricular performance and decreased contractility index). Our results show that MSCs ameliorate cardiac dysfunction associated with diabetic cardiomyopathy by lowering dyslipidemia and insulin resistance, inhibiting oxidative stress, and inflammation, downregulating JAK2/STAT3/iNOS and iNOS/Apoptosis signaling pathways.

Lavandula angustifolia Mill. inhibits high glucose and nicotine-induced Ca2+ influx in microglia and neuron-like cells via two distinct mechanisms

Smoking remains a significant health problem in patients with type 2 diabetes mellitus. This study compared intracellular Ca2+ ([Ca2+]i) in microglia, neurons, and astrocytes in the presence of high glucose (HG) and nicotine and evaluated the effects of Lavandula angustifolia Mill. essential oil (LEO) on this process. [Ca2+]i concentrations were measured by monitoring the fluorescence of Fura-2 acetoxymethyl ester. Treatment with HG and nicotine significantly increased [Ca2+]i in both microglia and neurons through Ca2+ influx from extracellular sources. This increased Ca2+ influx in microglia, however, was significantly reduced by LEO, an effect partially inhibited by the Na+/Ca2+ exchanger (NCX) inhibitor Ni2+. Ca2+ influx in neuron-like cells pretreated with HG plus nicotine was also significantly decreased by LEO, an effect partially inhibited by the L-type Ca2+ channel blocker nifedipine and the T-type Ca2+ channel blocker mibefradil. LEO or a two-fold increase in the applied number of astrocytes attenuated Ca2+ influx caused by high glucose and nicotine in the mixed cells of the microglia, neuron-like cells and astrocytes. These findings suggest that LEO can regulate HG and nicotine-induced Ca2+ influx into microglia and neurons through two distinct mechanisms.

Association of preoperative blood glucose level with delirium after non-cardiac surgery in diabetic patients

BACKGROUND

Hyperglycemia has shown a negative association with cognitive dysfunction. We analyzed patients with high preoperative blood glucose level and hemoglobin A1c (HbA1c) level to determine the prevalence of postoperative delirium.

METHODS

We reviewed a database of 23,532 patients with diabetes who underwent non-cardiac surgery. Acute hyperglycemia was defined as fasting blood glucose > 140 mg/dl or random glucose > 180 mg/dl within 24 h before surgery. Chronic hyperglycemia was defined as HbA1c level above 6.5% within three months before surgery. The incidence of delirium was compared according to the presence of acute and chronic hyperglycemia.

RESULTS

Of the 23,532 diabetic patients, 21,585 had available preoperative blood glucose level within 24 h before surgery, and 18,452 patients reported levels indicating acute hyperglycemia. Of the 8,927 patients with available HbA1c level within three months before surgery, 5,522 had levels indicating chronic hyperglycemia. After adjustment with inverse probability weighting, acute hyperglycemia was related to higher incidence of delirium (hazard ratio: 1.33, 95% CI [1.10,1.62], P = 0.004 for delirium) compared with controls without acute hyperglycemia. On the other hand, chronic hyperglycemia did not correlate with postoperative delirium.

CONCLUSIONS

Preoperative acute hyperglycemia was associated with postoperative delirium, whereas chronic hyperglycemia was not significantly associated with postoperative delirium. Irrespective of chronic hyperglycemia, acute glycemic control in surgical patients could be crucial for preventing postoperative delirium.

Advances in the Treatment of Autism Spectrum Disorder: Current and Promising Strategies

Autism spectrum disorder (ASD) is an umbrella term for developmental disorders characterized by social and communication impairments, language difficulties, restricted interests, and repetitive behaviors. Current management approaches for ASD aim to resolve its clinical manifestations based on the type and severity of the disability. Although some medications like risperidone show potential in regulating ASD-associated symptoms, a comprehensive treatment strategy for ASD is yet to be discovered. To date, identifying appropriate therapeutic targets and treatment strategies remains challenging due to the complex pathogenesis associated with ASD. Therefore, a comprehensive approach must be tailored to target the numerous pathogenetic pathways of ASD. From currently viable and basic treatment strategies, this review explores the entire field of advancements in ASD management up to cutting-edge modern scientific research. A novel systematic and personalized treatment approach is suggested, combining the available medications and targeting each symptom accordingly. Herein, summarize and categorize the most appropriate ways of modern ASD management into three distinct categories: current, promising, and prospective strategies.

Pyruvate dehydrogenase kinase 1 protects against neuronal injury and memory loss in mouse models of diabetes

Hyperglycemia-induced aberrant glucose metabolism is a causative factor of neurodegeneration and cognitive impairment in diabetes mellitus (DM) patients. The pyruvate dehydrogenase kinase (PDK)-lactic acid axis is regarded as a critical link between metabolic reprogramming and the pathogenic process of neurological disorders. However, its role in diabetic neuropathy remains unclear. Here, we found that PDK1 and phosphorylation of pyruvate dehydrogenase (PDH) were obviously increased in high glucose (HG)-stimulated primary neurons and Neuro-2a cell line. Acetyl-coA, a central metabolic intermediate, might enhance PDK1 expression via histone H3K9 acetylation modification in HG condition. The epigenetic regulation of PDK1 expression provided an available negative feedback pattern in response to HG environment-triggered mitochondrial metabolic overload. However, neuronal PDK1 was decreased in the hippocampus of streptozotocin (STZ)-induced diabetic mice. Our data showed that the expression of PDK1 also depended on the hypoxia-inducible factor-1 (HIF-1) transcriptional activation under the HG condition. However, HIF-1 was significantly reduced in the hippocampus of diabetic mice, which might explain the opposite expression of PDK1 in vivo. Importantly, overexpression of PDK1 reduced HG-induced reactive oxygen species (ROS) generation and neuronal apoptosis. Enhancing PDK1 expression in the hippocampus ameliorated STZ-induced cognitive impairment and neuronal degeneration in mice. Together, our study demonstrated that both acetyl-coA-induced histone acetylation and HIF-1 are necessary to direct PDK1 expression, and enhancing PDK1 may have a protective effect on cognitive recovery in diabetic mice. Schematic representation of the protective effect of PDK1 on hyperglycemia-induced neuronal injury and memory loss. High glucose enhanced the expression of PDK1 in an acetyl-coA-dependent histone acetylation modification to avoid mitochondrial metabolic overload and ROS release. However, the decrease of HIF-1 may impair the upregulation of PDK1 under hyperglycemia condition. Overexpression of PDK1 prevented hyperglycemia-induced hippocampal neuronal injury and memory loss in diabetic mice.

Effect of eIF2α in Neuronal Injury Induced by High Glucose and the Protective Mechanism of Resveratrol

Diabetes mellitus (DM) is a type of metabolic disease characterized by chronic hyperglycemia, which can lead to different degrees of cognitive decline. Therefore, it is crucial to explore the molecular biological mechanisms of neuronal injury. In this study, we investigated the effect of high glucose on eIF2α expression and the mechanism of neuronal injury, and on this basis, the protective mechanism of resveratrol is explored. Treatment with 50 mM high glucose in cortical neurons increased the levels of eIF2α phosphorylation; the expressions of ATF4 and CHOP increased. ISRIB alleviated high glucose-induced neuronal injury by reducing eIF2α phosphorylation when neurons were pretreated with ISRIB before high glucose treatment. Compared with the high glucose-treated group, resveratrol pretreatment reduced eIF2α phosphorylation, the levels of its downstream molecules ATF4 and CHOP, and LDH release. Resveratrol reduced the level of cortical eIF2α phosphorylation and the expression of its downstream molecules in DM mice and improved the ability of spatial memory and learning in DM mice without affecting anxiety and motor performance. Meanwhile, resveratrol modulated the expression of Bcl-2 protein and also effectively decreased the DM-induced up-regulation of Bax, caspase-3, p53, p21, and p16. Taken together, these results suggested that high glucose caused neuronal injury through the eIF2α/ATF4/CHOP pathway which was inhibited by ISRIB and resveratrol. The present study indicates that eIF2α is the new target for the treatment of high glucose-induced neuronal injury, and resveratrol is a potential new medicine to treat diabetes encephalopathy.

Neuroprotective Impact of Linagliptin against Cadmium-Induced Cognitive Impairment and Neuropathological Aberrations: Targeting SIRT1/Nrf2 Axis, Apoptosis, and Autophagy

Cadmium is an environmental contaminant associated with marked neurotoxicity and cognitive impairment. Linagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, has demonstrated promising neuroprotection against cerebral ischemia and diabetic dementia. However, there has been no study of its effect on cadmium-induced cognitive deficits. In the present work, linagliptin's prospective neuroprotective effects against cadmium-evoked cognitive decline were examined in vivo in rats. The molecular pathways related to oxidative stress, apoptosis, and autophagy were investigated. Histology, immunohistochemistry, ELISA, and biochemical assays were performed on brain hippocampi after receiving linagliptin (5 mg/kg/day). The current findings revealed that cadmium-induced learning and memory impairment were improved by linagliptin as seen in the Morris water maze, Y-maze, and novel object recognition test. Moreover, linagliptin lowered hippocampal neurodegeneration as seen in histopathology. At the molecular level, linagliptin curtailed hippocampal DPP-4 and augmented GLP-1 levels, triggering dampening of the hippocampal neurotoxic signals Aβ42 and p-tau in rats. Meanwhile, it enhanced hippocampal acetylcholine and GABA and diminished the glutamate spike. The behavioral recovery was associated with dampening of the hippocampal pro-oxidant response alongside SIRT1/Nrf2/HO-1 axis stimulation. Meanwhile, linagliptin counteracted hippocampal apoptosis markers and inhibited the pro-apoptotic kinase GSK-3β. In tandem, linagliptin activated hippocampal autophagy by lowering SQSTM-1/p62 accumulation, upregulating Beclin 1, and stimulating AMPK/mTOR pathway. In conclusion, linagliptin's antioxidant, antiapoptotic, and pro-autophagic properties advocated its promising neuroprotective impact. Thus, linagliptin may serve as a management approach against cadmium-induced cognitive deficits.

Cognitive dysfunction in diabetes: abnormal glucose metabolic regulation in the brain

Cognitive dysfunction is increasingly recognized as a complication and comorbidity of diabetes, supported by evidence of abnormal brain structure and function. Although few mechanistic metabolic studies have shown clear pathophysiological links between diabetes and cognitive dysfunction, there are several plausible ways in which this connection may occur. Since, brain functions require a constant supply of glucose as an energy source, the brain may be more susceptible to abnormalities in glucose metabolism. Glucose metabolic abnormalities under diabetic conditions may play an important role in cognitive dysfunction by affecting glucose transport and reducing glucose metabolism. These changes, along with oxidative stress, inflammation, mitochondrial dysfunction, and other factors, can affect synaptic transmission, neural plasticity, and ultimately lead to impaired neuronal and cognitive function. Insulin signal triggers intracellular signal transduction that regulates glucose transport and metabolism. Insulin resistance, one hallmark of diabetes, has also been linked with impaired cerebral glucose metabolism in the brain. In this review, we conclude that glucose metabolic abnormalities play a critical role in the pathophysiological alterations underlying diabetic cognitive dysfunction (DCD), which is associated with multiple pathogenic factors such as oxidative stress, mitochondrial dysfunction, inflammation, and others. Brain insulin resistance is highly emphasized and characterized as an important pathogenic mechanism in the DCD.

DNA Damage Response-Associated Cell Cycle Re-Entry and Neuronal Senescence in Brain Aging and Alzheimer's Disease

Chronological aging is by far the strongest risk factor for age-related dementia and Alzheimer's disease. Senescent cells accumulated in the aging and Alzheimer's disease brains are now recognized as the keys to describing such an association. Cellular senescence is a classic phenomenon characterized by stable cell arrest, which is thought to be applicable only to dividing cells. Emerging evidence indicates that fully differentiated post-mitotic neurons are also capable of becoming senescent, with roles in contributing to both brain aging and disease pathogenesis. The key question that arises is the identity of the upstream triggers and the molecular mechanisms that underly such changes. Here, we highlight the potential role of persistent DNA damage response as the major driver of senescent phenotypes and discuss the current evidence and molecular mechanisms that connect DNA repair infidelity, cell cycle re-entry and terminal fate decision in committing neuronal cell senescence.

High glucose-induced increasing reactive nitrogen species accumulation triggered mitochondrial dysfunction, inflammation, and apoptosis in keratinocytes

Growing evidence indicates that skin injuries are a common complication of diabetes. However, the cellular and molecular mechanisms of high glucose (HG) environment trigger nitrosative stress-mediated inflammation and apoptosis in keratinocytes remains unknown. Here we investigated whether reactive nitrogen species (RNS) induced by HG environment restrain antioxidant activity, and mitochondrial dysfunction leading to inflammation, and apoptosis via stress signaling pathways in keratinocytes. Our results established that the HG environment enhanced the production of nitric oxide (NO) and peroxynitrite anion (ONOO-) by inducible NO synthase (iNOS) in keratinocytes. Overproduction of RNS in HG environment suppress the antioxidants activity leading to mitochondrial dysfunction, characterized by loss of mitochondrial membrane potential (ΔΨm), increase in mitochondrial mass, decrease in mitochondrial transcription factor A(TFAM), increase in mitochondrial DNA (mtDNA) displacement loop (D-loop) and decrease in glycolytic flux concentration, which was attenuated by pharmacological inhibitors of NO/ONOO-, Nω-Nitro-l-argininemethyl ester hydrochloride (NAME)/hydralazine hydrochloride (Hyd.HCl). Excess production of RNS in HG environment restrained 8-oxoguanine DNA glycosylase-1 (OGG1) expression and increased 8-hydroxydeoxyguanosine (8-OHdG) accumulations in DNA were regulated by NO or ONOO-. Further, HG-induced RNA production caused an increase in the production of inflammatory mediators accompanied by activation of ERK1/2MAPK/Akt/tuberin-mTOR/IRF3 signaling cascade, lipid peroxidation (LPO), and protein carbonylation (PC) reactions followed by breakdown the cell-cell communication and apoptosis. Pre-treatment of cell with NAME/Hyd.HCl, diminished the expression of ERK1/2MAPK/Akt/tuberin-mTOR/IRF3, inflammatory mediators, and attenuated apoptosis in keratinocytes. Together, our results indicated that excess production of RNS in HG environment triggered inflammation and apoptosis, mediated by activation of ERK1/2MAPK/Akt/tuberin-mTOR/IRF3 signaling cascades in keratinocytes.

Impaired fasting glucose, oxidative distress, and cognitive impairment. Is this the starting point on DBT cognitive decline?

Different studies performed in human patients, animal models, and in vitro cell cultures, show a correlation between type 2 diabetes (DBT2) and certain neurodegenerative pathologies. Also, it was proposed that increased inflammation and- or oxidative distress are a possible cause of DBT2-accelerated cognitive decline. The onset of DBT2 is characterized by an increase in blood glucose levels due to (an inability of the body's cells to use insulin properly) called impaired fasting glucose (IFG). Genetic and/or molecular causes of IFG have not yet been established, but metabolic syndrome, obesity, unbalanced diets, and sedentary lifestyle would be responsible, at least in part, for the multiplication in the number of this disease. It has been proposed that hyperglycemia itself causes an imbalance in the redox state and could compromise blood-brain barrier (BBB) causing neurodegeneration. For this reason, we propose, in this review, to evaluate the available data about redox state and neurocognitive studies during the IFG period.

Crosstalk between circRNAs and the PI3K/AKT signaling pathway in cancer progression

Circular RNAs (circRNAs), covalently closed noncoding RNAs, are widely expressed in eukaryotes and viruses. They can function by regulating target gene expression, linear RNA transcription and protein generation. The phosphoinositide 3-kinase (PI3K)/AKT signaling pathway plays key roles in many biological and cellular processes, such as cell proliferation, growth, invasion, migration, and angiogenesis. It also plays a pivotal role in cancer progression. Emerging data suggest that the circRNA/PI3K/AKT axis modulates the expression of cancer-associated genes and thus regulates tumor progression. Aberrant regulation of the expression of circRNAs in the circRNA/PI3K/AKT axis is significantly associated with clinicopathological characteristics and plays an important role in the regulation of biological functions. In this review, we summarized the expression and biological functions of PI3K-AKT-related circRNAs in vitro and in vivo and assessed their associations with clinicopathological characteristics. We also further discussed the important role of circRNAs in the diagnosis, prognostication, and treatment of cancers.

Polygonatum sibiricum polysaccharide prevents depression-like behaviors by reducing oxidative stress, inflammation, and cellular and synaptic damage

ETHNOPHARMACOLOGICAL RELEVANCE

According to traditional Chinese medicine (TCM) theory (Yi Xue Zheng Zhuan), the main factors associated with the pathogenesis of depression are deficiencies relating to five zang organs, Qi, and blood. Polygonatum sibiricum F. Delaroche (PS), which may avert these pathological changes, has been used in a variety of formulas to treat depression. However, the effects and mechanism of action of PS, alone, and especially those of its main active component PS polysaccharide (PSP), on depression remain unexplored.

AIM OF THE STUDY

To determine the effects of PSP on depression-like behaviors and to elucidate its mechanism of action.

METHODS

PSP was isolated from dried PS rhizomes and qualified using transmission electron microscopy and Fourier transform infrared spectroscopy. Lipopolysaccharide (LPS) and chronic unpredictable mild stress (CUMS)-induced depression models were used to evaluate the antidepressive effects of PSP. Veinal blood and brain tissue were collected to determine the levels of hippocampal 5-HT, serum cortisol (CORT), brain and serum cytokines, and hippocampal oxidation-related indicators. The protein expression levels of phosphorylated extracellular signal-regulated kinase (p-ERK1/2), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), glial fibrillary acidic protein (GFAP), phosphorylated protein kinase B (p-Akt), phosphorylation of the mammalian target of rapamycin (mTOR), caspase-3, GluA1 and GluA2, and GluN2A and GluN2B were determined using western blotting and immunofluorescence. Nissl staining was performed to detect histopathological changes in brain tissues.

RESULTS

Injection of LPS (i.p.) induced depression-like behaviors, reduced the level of hippocampal 5-HT, increased the serum CORT level and hippocampal oxidative stress (ROS), and prompted the activation of ERK1/2, NF-κB, and GFAP and an inflammatory response. Conversely, PSP administration reduced these changes and prevented depression-like behaviors. PSP administration also promoted hippocampal expression of p-Akt, p-mTOR, GluA1, and GluA2; reduced the expression of caspase-3, GluN2A, and GluN2B; and prohibited the loss of granular cells in the DG region.

CONCLUSION

These results indicate that PSP prevents depression-like behaviors, and synaptic and neuronal damage probably by reducing ROS/HPA axis hyperfunction and the inflammatory response.

MALAT1 Regulated mTOR-Mediated Tau Hyperphosphorylation by Acting as a ceRNA of miR144 in Hippocampus Cells Exposed to High Glucose

Aim

High glucose (HG)-induced activation of mTOR promotes tau phosphorylation and leads to diabetes-associated dementia. This study aimed to explore the role of metastasis associated in lung adenocarcinoma transcript 1 (MALAT1) in HG-induced neuronal cell injury.

Methods

Hippocampus cells were isolated from C57BL/6J mice. After 6 days of culture, the cells were incubated with 5.5 mM glucose in normal medium or 75 mM glucose for 4 days. Cells were transfected with miR-144 mimic, miR-144 inhibitor, siRNA for MALAT1 or corresponding controls. Gene expression was detected by PCR and Western blot analysis.

Results

HG increased the levels of MALAT1 and p-tau in hippocampal cells. Knockdown of MALAT1 partially reversed the effects of HG on mTOR activity and p-tau protein levels. MALAT1 functioned as competing endogenous RNA (ceRNA) for miR-144, and pre-treatment with MALAT1 siRNA decreased mTOR activity and p-tau protein level in HG-treated hippocampal cells, which was significantly attenuated by miR-144 mimics. Moreover, miR-144 negatively regulated the expression of mTOR and knockdown of MALAT1 suppressed mTOR, while overexpression of mTOR abrogated protective effects of MALAT1 knockdown in HG-treated hippocampal cells.

Conclusion

MALAT1 knockdown prevented HG-induced mTOR activation and inhibited tau phosphorylation. MALAT1 may be a therapy target for diabetes associated dementia.

Inflammation and apoptosis, two key events induced by hyperglycemia mediated reactive nitrogen species in RGC-5 cells

Nitrosative stress plays a critical role in retinal injury in high glucose (HG) environment of eye, but the mechanisms remain poorly understood. Here we tested the hypothesis that HG induced reactive nitrogen species (RNS) production acts as a key functional mediator of antioxidant depletion, mitochondrial dysfunction, biomolecule damage, inflammation and apoptosis. Our findings illustrated that exposure of cultured RGC-5 cells to HG significantly disrupts the antioxidant defense mechanism and mitochondrial machineries by increasing the loss of mitochondrial membrane potential (ΔѰM) and elevating mitochondrial mass. Furthermore, we used biochemical tools to analyze the changes in metabolites, sulfur amino acids (SAAs) such as L-glutathione (GSH) and L-cysteine (Cys), in the presence of HG environment. These metabolic changes were followed by an increase in glycolytic flux that is phosphofructokinase-2 (PFK-2) activity. Moreover, HG exposure results in a significant disruption of protein carbonylation (PC) and lipid peroxidation (LPO), downregulation of OGG1 and increase in 8-OHdG accumulations in RGC-5 cells. In addition, our results demonstrated that HG environment coinciding with increased expression of inflammatory mediators, cell cycle deregulation, decreased in cell viability and expression of FoxOs, increased lysosomal content leading to apoptosis. Pre-treatment of selective inhibitors of RNS significantly reduced the HG-induced cell cycle deregulation and apoptosis in RGC-5 cells. Collectively, these results illustrated that accumulated RNS exacerbates the antioxidant depletion, mitochondrial dysfunction, biomolecule damage, inflammation and apoptosis induced by HG exposure in RGC-5 cells. Treatment of pharmacological inhibitors attenuated the HG induced in retinal cells.

Comparative Analysis of Multiple Neurodegenerative Diseases Based on Advanced Epigenetic Aging Brain

Background: Neurodegenerative Diseases (NDs) are age-dependent and include Alzheimer’s disease (AD), Parkinson’s disease (PD), progressive supranuclear palsy (PSP), frontotemporal dementia (FTD), and so on. There have been numerous studies showing that accelerated aging is closely related (even the driver of) ND, thus promoting imbalances in cellular homeostasis. However, the mechanisms of how different ND types are related/triggered by advanced aging are still unclear. Therefore, there is an urgent need to explore the potential markers/mechanisms of different ND types based on aging acceleration at a system level.

Methods: AD, PD, PSP, FTD, and aging markers were identified by supervised machine learning methods. The aging acceleration differential networks were constructed based on the aging score. Both the enrichment analysis and sensitivity analysis were carried out to investigate both common and specific mechanisms among different ND types in the context of aging acceleration.

Results: The extracellular fluid, cellular metabolisms, and inflammatory response were identified as the common driving factors of cellular homeostasis imbalances during the accelerated aging process. In addition, Ca ion imbalance, abnormal protein depositions, DNA damage, and cytoplasmic DNA in macrophages were also revealed to be special mechanisms that further promote AD, PD, PSP, and FTD, respectively.

Conclusion: The accelerated epigenetic aging mechanisms of different ND types were integrated and compared through our computational pipeline.

Hydrogen sulfide ameliorates high glucose-induced pro-inflammation factors in HT-22 cells: Involvement of SIRT1-mTOR/NF-κB signaling pathway

Hyperglycemia-induced neuroinflammation promotes the progression of diabetic encephalopathy. Hydrogen sulfide (H₂S) exerts anti-inflammatory and neuroprotective activities against neurodegenerative diseases. However, the effects of H₂S on hyperglycemia-induced neuroinflammation has not been investigated in neurons. Herein, by using HT-22 neuronal cells, we found that high glucose decreased the levels of endogenous H₂S and its catalytic enzyme, cystathionine-β-synthase (CBS). The administration of sodium hydrosulfide (NaHS, a H₂S donor) or S-adenosylmethionine (SAMe, an allosteric activator of CBS) restored high glucose-induced downregulation of CBS and H₂S levels. Importantly, H₂S ameliorated high glucose-induced inflammation in HT-22 cells, evidenced by NaHS or SAMe inhibited the pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) expression in HT-22 cells exposed to high glucose. Furthermore, NaHS or SAMe restored the SIRT1 level and the phosphorylation of mTOR and NF-κB p65 disturbed by high glucose in HT-22 cells, suggesting H₂S reversed high glucose-induced alteration of SIRT1-mTOR/NF-κB signaling pathway. Our results demonstrated that exogenous H₂S treatment or enhancing endogenous H₂S synthesis prevents the inflammatory processes in the neurons with the exposure of high glucose. Therefore, increasing the H₂S level using NaHS or SAMe might shed light on the prophylactic treatment of diabetic encephalopathy.

Effect of Probiotic, Prebiotic, and Synbiotic Supplementation on Cardiometabolic and Oxidative Stress Parameters in Patients With Chronic Kidney Disease: A Systematic Review and Meta-analysis

PURPOSE

Chronic kidney disease (CKD) is a major health problem worldwide. Evidence supporting the use of probiotic, prebiotic, and synbiotic supplementation in the management of CKD is mixed, although some studies suggest they may be useful. A systematic review and meta-analysis was performed to evaluate the effectiveness of probiotic, prebiotic, and synbiotic supplementation for improving cardiometabolic and oxidative stress parameters in patients with CKD.

METHODS

A comprehensive key word search was performed in EMBASE, Medline, Scopus, Cochrane Central, and Web of Science until April 2020. Randomized controlled trials investigating the effectiveness of probiotic, synbiotic, and prebiotic supplementation for the management of adults with CKD were included. Primary outcomes were measures of cardiometabolic parameters such as cholesterol and fasting blood glucose. Secondary outcomes were measures of oxidative stress (eg, malondialdehyde levels) and body mass index. Random effects meta-analyses were used to estimate mean treatment effects. Results are reported as standardized mean differences (SMDs) and 95% CIs.

FINDINGS

Fourteen articles were included. In patients with CKD, probiotic, prebiotic, and synbiotic supplementation significantly reduced total cholesterol (SMD, -0.25; 95% CI, -0.46 to -0.04; I² = 00.0%), fasting blood glucose (SMD, -0.41; 95% CI, -0.65 to -0.17; I² = 00.0%), homeostatic model assessment of insulin resistance (SMD, -0.63; 95% CI, -0.95 to -0.30; I² = 43.3%), insulin levels (SMD, -0.49; 95% CI, -0.90 to -0.08; I² = 65.2%), high-sensitivity C-reactive protein levels (SMD, -0.52; 95% CI, -0.81 to -0.22; I² = 52.7%), and malondialdehyde levels (SMD, -0.79; 95% CI, -1.22 to -0.37; I² = 69.8%) compared with control interventions. Supplementation significantly increased the quantitative insulin sensitivity check index (SMD, 0.78; 95% CI, 0.51 to 1.05; I² = 00.0%), total antioxidant capacity (SMD, 0.42; 95% CI, 0.18 to 0.66; I² = 00.0%), and glutathione levels (SMD, 0.52; 95% CI, 0.19 to 0.86; I² = 37.0%).

IMPLICATIONS

Probiotic, prebiotic, and synbiotic supplementation seems to be a promising intervention for improving cardiometabolic and oxidative stress parameters in patients with CKD.

Increased levels of YKL-40 in patients with diabetes mellitus: a systematic review and meta-analysis

BACKGROUND

Diabetes mellitus (DM) could be classified as type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), gestational diabetes mellitus (GDM) and others according to etiology and pathology. Diabetic nephropathy (DN) is one of the most serious complications of DM. YKL-40 is a marker of inflammation and some studies have indicated that DM was related with inflammation. The objective of our study is to perform a systematic review and meta-analysis to confirm the relationship between YKL-40 and DM as well as DN.

METHODS

Pubmed, Embase, CNKI and Chinese wanfang databases were searched for eligible studies by two independent authors. Studies were included in this meta-analysis if they fulfilled the following inclusion criteria: (1) a study involving the role of YKL-40 in DM (or DN) designed as a case-control study or cohort study; (2) the data of serum YKL-40 levels were available; (3) studies were published in English or Chinese. Finally, twenty-five studies were included in this meta-analysis.

RESULTS

Compared with healthy controls, DM patients had significantly higher levels of YKL-40 (DM: SMD = 1.62, 95% CI 1.08 to 2.25, P = 0.000; GDM: SMD = 2.85, 95% CI 1.01 to 4.70, P = 0.002). Additionally, DM patients with different degree of albuminuria had significantly higher levels of YKL-40 compared with healthy controls (normoalbuminuria: SMD = 1.58, 95% CI 0.59 to 2.56, P = 0.002; microalbuminuria: SMD = 2.57, 95% CI 0.92 to 4.22, P = 0.002; macroalbuminuria: SMD = 2.69, 95% CI 1.40 to 3.98, P = 0.000) and serum YKL-40 levels increased with increasing severity of albuminuria among DM patients (microalbuminuria vs normoalbuminuria: SMD = 1.49, 95% CI 0.28 to 2.71, P = 0.016; macroalbuminuria vs microalbuminuria: SMD = 0.93, 95% CI 0.34 to 1.52, P = 0.002).

CONCLUSIONS

Our current meta-analysis demonstrates that serum level of YKL-40 is increased in DM and positively associated with the severe degree of albuminuria. Therefore, we suggest that YKL-40 could be considered to be detected, along with other inflammatory markers, if DM, especially DN, is suspected.

Unsupervised clustering of multiparametric fluorescent images extends the spectrum of detectable cell membrane phases with sub-micrometric resolution

Solvatochromic probes undergo an emission shift when the hydration level of the membrane environment increases and are commonly used to distinguish between solid-ordered and liquid-disordered phases in artificial membrane bilayers. This emission shift is currently limited in unraveling the broad spectrum of membrane phases of natural cell membranes and their spatial organization. Spectrally resolved fluorescence lifetime imaging can provide pixel-resolved multiparametric information about the biophysical state of the membranes, like membrane hydration, microviscosity and the partition coefficient of the probe. Here, we introduce a clustering based analysis that, leveraging the multiparametric content of spectrally resolved lifetime images, allows us to classify through an unsupervised learning approach multiple membrane phases with sub-micrometric resolution. This method extends the spectrum of detectable membrane phases allowing to dissect and characterize up to six different phases, and to study real-time phase transitions in cultured cells and tissues undergoing different treatments. We applied this method to investigate membrane remodeling induced by high glucose on PC-12 neuronal cells, associated with the development of diabetic neuropathy. Due to its wide applicability, this method provides a new paradigm in the analysis of environmentally sensitive fluorescent probes.

Urolithin A suppresses high glucose-induced neuronal amyloidogenesis by modulating TGM2-dependent ER-mitochondria contacts and calcium homeostasis

Hyperglycemia in diabetes mellitus (DM) patients is a causative factor for amyloidogenesis and induces neuropathological changes, such as impaired neuronal integrity, neurodegeneration, and cognitive impairment. Regulation of mitochondrial calcium influx from the endoplasmic reticulum (ER) is considered a promising strategy for the prevention of mitochondrial ROS (mtROS) accumulation that occurs in the Alzheimer's disease (AD)-associated pathogenesis in DM patients. Among the metabolites of ellagitannins that are produced in the gut microbiome, urolithin A has received an increasing amount of attention as a novel candidate with anti-oxidative and neuroprotective effects in AD. Here, we investigated the effect of urolithin A on high glucose-induced amyloidogenesis caused by mitochondrial calcium dysregulation and mtROS accumulation resulting in neuronal degeneration. We also identified the mechanism related to mitochondria-associated ER membrane (MAM) formation. We found that urolithin A-lowered mitochondrial calcium influx significantly alleviated high glucose-induced mtROS accumulation and expression of amyloid beta (Aβ)-producing enzymes, such as amyloid precursor protein (APP) and β-secretase-1 (BACE1), as well as Aβ production. Urolithin A injections in a streptozotocin (STZ)-induced diabetic mouse model alleviated APP and BACE1 expressions, Tau phosphorylation, Aβ deposition, and cognitive impairment. In addition, high glucose stimulated MAM formation and transglutaminase type 2 (TGM2) expression. We first discovered that urolithin A significantly reduced high glucose-induced TGM2 expression. In addition, disruption of the AIP-AhR complex was involved in urolithin A-mediated suppression of high glucose-induced TGM2 expression. Markedly, TGM2 silencing inhibited inositol 1, 4, 5-trisphosphate receptor type 1 (IP3R1)-voltage-dependent anion-selective channel protein 1 (VDAC1) interactions and prevented high glucose-induced mitochondrial calcium influx and mtROS accumulation. We also found that urolithin A or TGM2 silencing prevented Aβ-induced mitochondrial calcium influx, mtROS accumulation, Tau phosphorylation, and cell death in neuronal cells. In conclusion, we suggest that urolithin A is a promising candidate for the development of therapies to prevent DM-associated AD pathogenesis by reducing TGM2-dependent MAM formation and maintaining mitochondrial calcium and ROS homeostasis.

The Role of Aberrant Metabolism in Cancer: Insights Into the Interplay Between Cell Metabolic Reprogramming, Metabolic Syndrome, and Cancer

Metabolic syndrome (MetS) is characterized by hyperglycemia, hypertension, dyslipidemia and abdominal obesity. Patients with MetS or other metabolic disorders are more susceptible to cancer development and recurrence and have a worse long-term prognosis. Moreover, the metabolic reprogramming observed in cancer cells has also been described as one of the new hallmarks of cancer. Thus, aberrant metabolism has been proposed as an important risk factor for cancer. Chronic inflammation, reactive oxygen species (ROS), and oncogenic signaling pathways are considered as main potential triggers. Considering the strong association between metabolism and cancer, metabolism-modulating drugs, including metformin and statins, as well as adopting a healthy lifestyle, have been extensively investigated as strategies to combat cancer. Furthermore, strategies that interfere with the metabolic rewiring of cells may also have potent anti-cancer effects. In this article, we provide a comprehensive review of current knowledge on the relationship between aberrant metabolism and cancer and discuss the potential use of metabolism-targeting strategy for the treatment of cancer.

Damage and Phenotype Change in PC12 Cells Induced by Lipopolysaccharide Can Be Inhibited by Antioxidants Through Reduced Cytoskeleton Protein Synthesis

The present study investigated changes in cellular phenotype and oxidative stress during the inflammatory response in PC12 cells stimulated by lipopolysaccharide (LPS) and assessed the effects of minocycline, astragalus (AST), and baicalin on inflammation. PC12 cells were exposed to LPS with or without minocycline, AST, or baicalin. Cell viability was measured by a thiazolyl blue tetrazolium bromide (MTT) assay. Contrast and laser confocal microscopy were used to analyze changes in cellular phenotype and cytoskeleton synthesis. Western blotting tested the expression of α7nAChR and vimentin. Inhibitory ratio of superoxide dismutase (SOD) activity and leakage of lactate dehydrogenase (LDH) were detected to evaluate cellular oxidative stress. Results showed that LPS could attenuate PC12 cell viability in a time- and dose-dependent manner, which could be rescued by minocycline. In addition, minocycline could reverse PC12 cell phenotypic change and the synthesis of the mesenchymal cytoskeleton protein vimentin, both induced by LPS. During LPS-initiated inflammation, α7nAChR and vimentin expression were obviously inhibited by minocycline, AST, or baicalin. The inhibitory rate of SOD activity and LDH leakage in PC12 cells were increased by LPS and attenuated significantly when exposed to minocycline, AST, or baicalin. These findings suggest phenotype change, altered cytoskeleton protein synthesis, and oxidative stress are all involved in the inflammatory response in PC12 cells during which α7 nicotinic acetylcholine receptor (α7nAChR) is induced by LPS stimulation. Minocycline, AST, and baicalin have a protective effect against PC12 cell injury, acting as antioxidants and inhibitors of mesenchymal proteins.

CEES-induced ROS accumulation regulates mitochondrial complications and inflammatory response in keratinocytes

Reactive oxygen species (ROS) is mainly produced as a by-product from electron transport chain (ETC) of mitochondria and effectively eliminated by cellular antioxidants. However, 2-chloroethyl ethyl sulfide (CEES) exposure to keratinocytes declined antioxidant capacity and increased accumulation of ROS triggered alteration of mitochondrial activity and apoptosis is lacking. Our findings demonstrated that the electron leakage from the impaired ETC, leading to the accumulation of ROS was gradually elevating with increasing concentration of CEES exposure, which decline the activity of superoxide dismutase (SOD), manganese SOD (MnSOD) and copper-zinc SOD (Cu-ZnSOD) in keratinocytes. Further, excess accumulation of ROS, decreased the mitochondrial membrane potential (ΔΨm) and increased the mitochondrial mass with increasing dose of CEES. CEES exposure provoked the decrease in expression of transcription factor A mitochondrial (TFAM), augmented mitochondrial DNA (mtDNA) damage and altered the mtDNA-encoded oxidative phosphorylation (OXPHOS) subunits. Moreover, fragmented mtDNA translocated into cytosol, where it activated cGAS-STING and interferon regulatory factor3 (IRF3), coinciding with the increased expression of inflammatory mediators and alteration of cell-to-cell communication markers. Pre-treatment of N-acetyl-l-cysteine (NAC) or L-Nω-nitroarginine methyl ester (NAME), hydralazine hydrochloride (Hyd·HCl) or ERK1/2 or phosphoinositide3-kinase (PI3-K)/Akt inhibitors in keratinocyte cells significantly restored the CEES effect. Our findings suggest that CEES-induced mitochondrial ROS production and accumulation leads to mitochondrial dysfunction and inflammatory response in keratinocytes. However, treatment of antioxidants or ERK1/2 or PI3-K/Akt inhibitors is a novel therapeutic option for the keratinocytes complication.

IGF-1 Via PI3K/Akt/S6K Signaling Pathway Protects DRG Neurons with High Glucose-induced Toxicity

Hyperglycemia-induced toxicity of neurons contributes to the pathogenesis and progression of diabetic neuropathy (DNP). High concentration glucose triggered reactive oxygen species (ROS) overproduction and induced cell apoptosis of neurons from dorsal root ganglion (DRG) in vitro. Currently, there is no effective therapeutic method to retard this devastating complication or neurotoxicity induced by high glucose. Insulin-like growth factor-1 (IGF-1) has multi-neurotrophic actions which need to be explored regarding its actions and mechanisms on relieving high glucose induced neurotoxicity. Herein, high concentration glucose was exposed to the DRG neurons in vitro. The effects of IGF-1 on relieving high glucose-induced neurotoxicity were evaluated. We illustrated that IGF-1 enhanced regeneration of neurites sent from DRG neuronal cell bodies and increased neuronal viability which inhibited by high glucose challenge. IGF-1 alleviated neuronal apoptosis caused by high glucose exposure. IGF-1 also suppressed the intracellular ROS overproduction and ATF3 expression upregulation which was induced by high glucose insult. The anti-neurotoxic effects of IGF-1 might be through restoration of prosurvival PI3K/Akt/S6K signaling. These data shed some light on the treatment of intractable DNP and suggested that IGF-1 might be a potential effective agent on relieving high glucose induced neurotoxicity.

High glucose augments ROS generation regulates mitochondrial dysfunction and apoptosis via stress signalling cascades in keratinocytes

Mitochondria are fascinating structures of the cellular compartments that generate energy to run the cells. However, inherent disorders of mitochondria due to diabetes can cause major disruption of metabolism that produces huge amount of reactive oxygen species (ROS). Here we study the elevated level of ROS provoked by high glucose (HG) environment triggered mitochondrial dysfunction, inflammatory response and apoptosis via stress signalling pathway in keratinocytes. Our results demonstrated that elevated glucose level in keratinoctes, increase the accumulations of ROS and decrease in cellular antioxidant capacities. Moreover, excess production of ROS was associated with mitochondrial dysfunction, characterized by loss of mitochondrial membrane potential (ΔΨm), increase in mitochondrial mass, alteration of mitochondrial respiratory complexes, cytochrome c (Cyt c) release, decrease in mitochondrial transcription factor A (TFAM) and increase in mitochondrial DNA (mtDNA) fragmentation. Damaged mtDNA escaped into the cytosol, where it engaged the activation of ERK1/2, PI3K/Akt, tuberin and mTOR via cGAS-STING leading to IRF3 activation. Pre-treatment of pharmacological inhibitors, ERK1/2 or PI3K/Akt suppressed the IRF3 activation. Furthermore, our results demonstrated that activation of IRF3 in HG environment coinciding with increased expression of inflammatory mediators. Excess production of ROS interfered with decreased in cell viability, increased lysosomal content and expression of FoxOs, leading to cell cycle deregulation and apoptosis. Pre-treatment of N-acetyl-l-cysteine (NAC) significantly reduced the HG-induced cell cycle deregulation and apoptosis in keratinocytes. In conclusion, increased oxidative stress underlies the decrease in antioxidant capacities and mitochondrial dysfunction in HG environment correlate with inflammation response and apoptosis via ERK1/2-PI3K/Akt-IRF3 pathway in keratinoctes.

Improvement in Impaired Social Cognition but Not Seizures by Everolimus in a Child with Tuberous Sclerosis-Associated Autism through Increased Serum Antioxidant Proteins and Oxidant/Antioxidant Status

We investigated the effect of the mammalian target of rapamycin (mTOR) inhibitor everolimus on tuberous sclerosis complex- (TSC-) associated autistic symptoms and focal seizures with impaired awareness in a female child with TSC. We further evaluated the relationship between improved autistic symptoms and seizures and increased the serum levels of the antioxidant proteins, ceruloplasmin (Cp) and transferrin (Tf), and oxidant-antioxidant status indicated by the oxidant marker oxidized low-density lipoprotein (ox-LDL) and the antioxidant marker total antioxidant power (TAP). Everolimus treatment improved impaired social cognition and autistic behaviors; however, seizure and epileptic activity persisted. Serum Cp and Tf levels gradually increased in response to improved autistic symptoms. Serum TAP levels gradually decreased from baseline to the lowest value at 16 weeks and then increased at 24 weeks, showing a trend toward decreased total score of the Aberrant Behavior Checklist. This study revealed that everolimus treatment improved impaired social cognition with increased serum levels of the copper mediator (Cp) and iron mediator (Tf) via homeostatic control of mTOR activity accompanied by overlap of the oxidant-antioxidant system. Everolimus had no effect on TSC-related epileptiform discharges, and thus, the autistic symptoms and epileptic activity may be two independent end results of a common central nervous system disorder including mTOR hyperactivity. This trial is registered with JMAS-IIA00258.

Pterostilbene Attenuates Astrocytic Inflammation and Neuronal Oxidative Injury After Ischemia-Reperfusion by Inhibiting NF-κB Phosphorylation

Astrocyte-mediated inflammation and oxidative stress elicit cerebral ischemia-reperfusion (IR) injury after stroke. Nuclear factor (NF)-κB activates astrocytes and generates pro-inflammatory factors. The purpose of the present study is to elucidate the effect of pterostilbene (PTE, a natural stilbene) on astrocytic inflammation and neuronal oxidative injury following cerebral ischemia-reperfusion injury. A middle cerebral artery occlusion-reperfusion (MCAO/R) mouse model and HT22/U251 co-culture model subjected to oxygen-glucose deprivation and re-introduction (OGD/R) were employed, with or without PTE treatment. The data showed that PTE delivery immediately after reperfusion, at 1 h after occlusion, decreased infarct volume, brain edema, and neuronal apoptosis and improved long-term neurological function. PTE decreased oxidation (i.e., production of reactive oxygen species, malondialdehyde) and inflammatory mediators (tumor necrosis factor-α, interleukin-1β, and interleukin-6) and increased anti-oxidative enzyme activities (i.e., of superoxide dismutase, glutathione peroxidase), by inhibiting phosphorylation and nuclear translocation of NF-κB. In conclusion, PTE attenuated astrocyte-mediated inflammation and oxidative injury following IR via NF-κB inhibition. Overall, PTE is a promising neuroprotective agent.

Hydrogen Sulfide Inhibits High Glucose-Induced Neuronal Senescence by Improving Autophagic Flux via Up-regulation of SIRT1

Hyperglycemia, a key characteristic and risk factor for diabetes mellitus (DM), causes neuronal senescence. Hydrogen sulfide (H₂S) is a novel neuroprotectant. The present work was to investigate the potential effect of H₂S on hyperglycemia-induced neuronal senescence and the underlying mechanisms. We found that NaHS, a donor of H₂S, inhibited high glucose (HG)-induced cellular senescence in HT22 cells (an immortalized mouse hippocampal cell line), as evidenced by a decrease in the number of senescence associated-β-galactosidase (SA-β-gal) positive cells, increase in the growth of cells, and down-regulations of senescence mark proteins, p16^INK4a and p21^CIP1. NaHS improved the autophagic flux, which is judged by a decrease in the amount of intracellular autophagosome as well as up-regulations of LC3II/I and P62 in HG-exposed HT22 cells. Furthermore, blocked autophagic flux by chloroquine (CQ) significantly abolished NaHS-exerted improvement in the autophagic flux and suppression in the cellular senescence of GH-exposed HT22 cells, which indicated that H₂S antagonizes HG-induced neuronal senescence by promoting autophagic flux. We also found that NaHS up-regulated the expression of silent mating type information regulation 2 homolog 1 (SIRT1), an important anti-aging protein, in HG-exposed HT22 cells. Furthermore, inhibition of SIRT1 by sirtinol reversed the protection of H₂S against HG-induced autophagic flux blockade and cellular senescence in HT22 cells. These data indicated that H₂S protects HT22 cells against HG-induced neuronal senescence by improving autophagic flux via up-regulation of SIRT1, suggesting H₂S as a potential treatment strategy for hyperglycemia-induced neuronal senescence and neurotoxicity.

High-glucose medium induces cellular differentiation and changes in metabolic functionality of oligodendroglia

Oligodendrocyte precursor cells (OPC) are a uniformly distributed population of glial cells that are well known for proliferating and differentiating into mature oligodendrocytes to form the myelin sheet in the central nervous system (CNS). Since monocarboxylate transporter 1 (MCT1) has shown to be expressed by oligodendroglia, the involvement of these cells with the metabolic support to axons has emerged as an important role in the maintenance of neuronal functionality. Hyperglycemia is a metabolic dysfunction highly associated with oxidative stress, a classical feature linked to many disorders such as diabetes mellitus. Despite of being widely investigated in several different cell cultures, including astrocytes and neurons, such condition has been poorly investigated in OPC culture. Thus, the aim of this study was to explore the possible effects of high-glucose exposure in acute and chronic conditions on oligodendroglial development and functionality in vitro. In this sense, we have demonstrated that under high-glucose exposure OPC improved its differentiation rate without affecting its membrane integrity and its morphology. Besides, chronic high-glucose condition also increased glucose uptake and lactate release. On the other hand, our findings also showed that, unlike what happens in other glial cells and neurons, high-glucose exposure did not seem to induce oxidative stress in OPC culture. Therefore, as far as we have investigated in this present study, we suggest that OPC may be able to support neurons and other glial cells during hyperglycemia events.

The Cross-Talk Between Sphingolipids and Insulin-Like Growth Factor Signaling: Significance for Aging and Neurodegeneration

Bioactive sphingolipids: sphingosine, sphingosine-1-phosphate (S1P), ceramide, and ceramide-1-phosphate (C1P) are increasingly implicated in cell survival, proliferation, differentiation, and in multiple aspects of stress response in the nervous system. The opposite roles of closely related sphingolipid species in cell survival/death signaling is reflected in the concept of tightly controlled sphingolipid rheostat. Aging has a complex influence on sphingolipid metabolism, disturbing signaling pathways and the properties of lipid membranes. A metabolic signature of stress resistance-associated sphingolipids correlates with longevity in humans. Moreover, accumulating evidence suggests extensive links between sphingolipid signaling and the insulin-like growth factor I (IGF-I)-Akt-mTOR pathway (IIS), which is involved in the modulation of aging process and longevity. IIS integrates a wide array of metabolic signals, cross-talks with p53, nuclear factor κB (NF-κB), or reactive oxygen species (ROS) and influences gene expression to shape the cellular metabolic profile and stress resistance. The multiple connections between sphingolipids and IIS signaling suggest possible engagement of these compounds in the aging process itself, which creates a vulnerable background for the majority of neurodegenerative disorders.

Curcumin analogues attenuate Aβ25-35-induced oxidative stress in PC12 cells via Keap1/Nrf2/HO-1 signaling pathways

Beta-amyloid (Aβ) has pivotal functions in the pathogenesis of Alzheimer's Disease (AD). In the present study, we adopted an vitro model that involved Aβ_25-35-induced oxidative damage in PC12 cells. Aβ_25-35 (10 μΜ) treatment for 24 h induced significant cell death and oxidative stress in PC12 cells, as evidenced by cell viability reduction, LDH release, ROS accumulation and increased production MDA. (1E,4E)-1, 5-bis(4-hydroxy-3-methoxyphenyl) penta-1, 4-dien-3-one (CB) and (1E, 4E)-1-(3, 4-dimethoxyphenyl)-5-(4-hydroxy-3, 5-dime-thoxyphenyl) Penta-1, 4-dien-3-one (FE), two Curcumin (Cur) analogues displayed neuroprotective effects against Aβ_25-35-induced oxidative damage and cellular apoptosis in PC12 cells. Here, we investigated three different treatment ways of CB and FE. It was interesting that post-treatment of CB and FE (restoring way) showed similar effect to the preventive way, while attenuating way did not show any protective effect. We found that low dose CB and FE increased transcriptional factor NF-E2-related factor 2 (Nrf2)/hemo oxygenase 1 (HO-1) protein expression and decreased Kelch-like ECH-associated protein 1 (Keap1) in PC 12 cells. In addition, CB and FE promoted the translation of Nrf2 into nuclear and enhanced the activity of superoxide dismutase (SOD)/catalase, which confirmed cytoprotection against Aβ_25-35-induced oxidative damage. Moreover, CB and FE could increase Bcl-2 expression level, decrease the level of Bax and Cyt-c in Aβ_25-35-treated PC12 cells. Ultimately, the neuroprotective effect of CB and FE provides a pharmacological basis for its clinical use in prevention and treatment of AD.

Prevention of kidney cell damage in hyperglycaemia condition by adiponectin

Adiponectin (APN) is an adipocytokine, secreted from adipose tissue and has anti-inflammatory, anti-ageing, and antidiabetic properties. Hyperglycaemia can damage the renal cells, and mammalian target of rapamycin (mTOR), along with Sirtuin 1 (SIRT1), have an important role in kidney cell response to hyperglycaemia. Therefore, understanding the relationship between adiponectin, mTOR, and SIRT1 proteins is beneficial for deciphering the mechanism of adiponectin function. In this study, Human Embryonic Kidney-293 (HEK-293) cells were cultured under normal and high-glucose condition, with and without APN (1, 10, and 100 ng/mL) for 48 hours. mTOR protein expression was evaluated by western blot analysis, and SIRT1 protein was assessed using ELISA method. To evaluate hyperglycaemia-mediated cytotoxicity, cell viability was determined using MTT assay. Data showed that APN in high dose (100 ng/mL) significantly reduced the expression of mTOR and p-mTOR, increased SIRT1 protein, and also improved cell viability compared with the control high glucose (p ≤ 0.05). According to this results, APN can be useful in preventing renal cell damage, by affecting on the expression of mTOR and SIRT1 proteins, as well as increasing the survival of kidney cells in hyperglycaemia conditions. SIGNIFICANCE OF THE STUDY: Adiponectin triggered mTOR/p-mTOR/SIRT1 pathway and decreased cell death in human kidney cells. Our findings provide preliminary experimental data that support further studies on the potential therapeutic role of adiponectin in diabetes and diabetic-induced metabolic complications.

Oxidative stress, antioxidant capacity, biomolecule damage, and inflammation symptoms of sickle cell disease in children

BACKGROUND

The phenotypic expression of sickle cell disease (SCD) is a complex pathophysiologic condition. However, sickle erythrocytes might be the cause for multiple sources of pro-oxidant processes with consequent linked to chronic and systemic oxidative stress. Herein, we explored the SCD phenomena could be the result in formation of oxidative stress as well as inflammation in children.

MATERIAL AND METHODS

Blood samples of 147 SCD subjects were evaluated. A control group was formed of 156 individuals without SCD. Different oxidative stress markers and inflammatory mediators were measured by using various biochemical techniques. Plasma samples were collected from blood for the measurement of antioxidants and reactive oxygen species (ROS).

RESULTS

The levels of plasma hydroxyl radical (HO•), and nitric oxide (NO) production were higher in SCD children in compared to control groups. The plasma antioxidants capacities such as superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione peroxidase (GPx) and protein thiol levels were significantly reduced in SCD children. The plasma lipid peroxidation, protein carbonylation, DNA damage markers were significantly altered in different age groups of SCD children. Further, our results showed that SCD children have chronic inflammatory disease due to persistent alteration of haemoglobin content, reticulocyte, total bilirubin, platelet, creatinine, leukocytes, and altered expression of inflammatory mediators in compared to control groups.

CONCLUSION

SCD children have high oxidative stress, and conversely, decreased antioxidant activity. Decrease in antioxidant activity might explained the reduction in lipid peroxidation, protein carbonylation and increased inflammation, which in turn intensify the symptoms of SCD in children.

High glucose forces a positive feedback loop connecting ErbB4 expression and mTOR/S6K pathway to aggravate the formation of tau hyperphosphorylation in differentiated SH-SY5Y cells

High glucose (HG)-induced mammalian target of rapamycin (mTOR) overactivation acts as a signaling hub for the formation of tau hyperphosphorylation, which contributes to the development of diabetes-associated cognitive deficit. How HG induces the sustained activation of mTOR in neurons is not clearly understood. ErbB4, a member of the receptor tyrosine kinase family, plays critical roles in development and function of neural circuitry, relevant to behavioral deficits. Here, we showed HG-induced ErbB4 overexpression in differentiated SH-SY5Y cells and primary hippocampal neurons and hippocampal pyramidal neurons of streptozotocin-induced diabetic rats. Inhibition of ErbB4 signaling prevented the HG-induced activation of mTOR/S6K signaling to suppress tau hyperphosphorylation. In contrast, ErbB4 overexpression increased the activation of mTOR/S6K signaling, resulting in tau hyperphosphorylation similar to HG treatment. We also demonstrated that HG upregulated the expression of ErbB4 at a mTOR-dependent posttranscriptional level. Together, our results provide the first evidence for the presence of a positive feedback loop for the sustained activation of mTOR involving overexpressed ErbB4, leading to the formation of tau hyperphosphorylation under HG condition. Therefore, ErbB4 is a potential therapeutic target for diabetes-associated neurodegeneration.

Shared pathological pathways of Alzheimer's disease with specific comorbidities: current perspectives and interventions

Alzheimer's disease (AD) belongs to one of the most multifactorial, complex and heterogeneous morbidity-leading disorders. Despite the extensive research in the field, AD pathogenesis is still at some extend obscure. Mechanisms linking AD with certain comorbidities, namely diabetes mellitus, obesity and dyslipidemia, are increasingly gaining importance, mainly because of their potential role in promoting AD development and exacerbation. Their exact cognitive impairment trajectories, however, remain to be fully elucidated. The current review aims to offer a clear and comprehensive description of the state-of-the-art approaches focused on generating in-depth knowledge regarding the overlapping pathology of AD and its concomitant ailments. Thorough understanding of associated alterations on a number of molecular, metabolic and hormonal pathways, will contribute to the further development of novel and integrated theranostics, as well as targeted interventions that may be beneficial for individuals with age-related cognitive decline.

Enhancement of high glucose-induced PINK1 expression by melatonin stimulates neuronal cell survival: Involvement of MT2 /Akt/NF-κB pathway

Hyperglycemia is a representative hallmark and risk factor for diabetes mellitus (DM) and is closely linked to DM-associated neuronal cell death. Previous investigators reported on a genome-wide association study and showed relationships between DM and melatonin receptor (MT), highlighting the role of MT signaling by assessing melatonin in DM. However, the role of MT signaling in DM pathogenesis is unclear. Therefore, we investigated the role of mitophagy regulators in high glucose-induced neuronal cell death and the effect of melatonin against high glucose-induced mitophagy regulators in neuronal cells. In our results, high glucose significantly increased PTEN-induced putative kinase 1 (PINK1) and LC-3B expressions; as well it decreased cytochrome c oxidase subunit 4 expression and Mitotracker™ fluorescence intensity. Silencing of PINK1 induced mitochondrial reactive oxygen species (ROS) accumulation and mitochondrial membrane potential impairment, increased expressions of cleaved caspases, and increased the number of annexin V-positive cells. In addition, high glucose-stimulated melatonin receptor 1B (MTNR1B) mRNA and PINK1 expressions were reversed by ROS scavenger N-acetyl cysteine pretreatment. Upregulation of PINK1 expression in neuronal cells is suppressed by pretreatment with MT₂ receptor-specific inhibitor 4-P-PDOT. We further showed melatonin stimulated Akt phosphorylation, which was followed by nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) phosphorylation and nuclear translocation. Silencing of PINK1 expression abolished melatonin-regulated mitochondrial ROS production, cleaved caspase-3 and caspase-9 expressions, and the number of annexin V-positive cells. In conclusion, we have demonstrated the melatonin stimulates PINK1 expression via an MT₂ /Akt/NF-κB pathway, and such stimulation is important for the prevention of neuronal cell apoptosis under high glucose conditions.

Gold nanoparticles reduce high glucose-induced oxidative-nitrosative stress regulated inflammation and apoptosis via tuberin-mTOR/NF-κB pathways in macrophages

Hyperglycemia is a risk factor for cardiovascular mortality and morbidity, and directly responsible for exacerbating macrophage activation and atherosclerosis. We showed that gold nanoparticles (AuNPs) reduce the high glucose (HG)-induced atherosclerosis-related complications in macrophages via oxidative-nitrosative stress-regulated inflammation and apoptosis. The effects of AuNPs on oxidative-nitrosative stress markers such as cellular antioxidants were attenuated by HG exposure, leading to reduction in the accumulation of reactive oxygen/nitrogen species in cellular compartments. Further, these abnormalities of antioxidants level and reactive oxygen/nitrogen species accumulations initiate cellular stress, resulting in the activation of nuclear factor κB (NF-κB) via ERK1/2mitogen-activated protein kinase (MAPK)/Akt/tuberin-mammalian target of rapamycin (mTOR) pathways. The activated NF-κB stimulates inflammatory mediators, which subsequently subdue biomolecules damage, leading to aggravation of the inflammatory infiltration and immune responses. Treatment of AuNPs inhibits the intracellular redox-sensitive signaling pathways, inflammation, and apoptosis in macrophages. Together, our results indicate that AuNPs may modulate HG-induced oxidative-nitrosative stress. These effects may be sealed tight due to the fact that AuNPs treatment reduces the activation of NF-κB by ERK1/2MAPK/Akt/tuberin-mTOR pathways-mediated inflammatory genes expression and cellular stress responses, which may be beneficial for minimizing the atherosclerosis.

High glucose induces formation of tau hyperphosphorylation via Cav-1-mTOR pathway: A potential molecular mechanism for diabetes-induced cognitive dysfunction

The abnormally hyperphosphorylated tau is thought to be implicated in diabetes-associated cognitive deficits. The role of mammalian target of rapamycin (mTOR) / S6 kinase (S6K) signalling in the formation of tau hyperphosphorylation has been previously studied. Caveolin-1 (Cav-1), the essential structure protein of caveolae, promotes neuronal survival and growth, and inhibits glucose metabolism. In this study, we aimed to investigate the role of Cav-1 in the formation of tau hyperphosphorylation under chronic hyperglycemic condition (HGC). Diabetic rats were induced by streptozotocin (STZ). Primary hippocampal neurons with or without molecular intervention such as the transient over-expression or knock-down were subjected to HGC. The obtained experimental samples were analyzed by real time quantitative RT-PCR, Western blot, immunofluorescence or immunohistochemisty. We found: 1) that a chronic HGC directly decreases Cav-1 expression, increases tau phosphorylation and activates mTOR/S6K signalling in the brain neurons of diabetic rats, 2) that overexpression of Cav-1 attenuates tau hyperphosphorylation induced by chronic HGC in primary hippocampal neurons, whereas down-regulation of Cav-1 using Cav-1 siRNA dramatically worsens tau hyperphosphorylation via mTOR/S6K signalling pathway, and 3) that the down-regulation of Cav-1 induced by HGC is independent of mTOR signalling. Our results suggest that tau hyperphosphorylation and the sustained over-activated mTOR signalling under hyperglycemia may be due to the suppression of Cav-1. Therefore, Cav-1 is a potential therapeutic target for diabetes-induced cognitive dysfunction.

Streptozotocin produces oxidative stress, inflammation and decreases BDNF concentrations to induce apoptosis of RIN5F cells and type 2 diabetes mellitus in Wistar rats

BACKGROUND

Neurodegenerative disorders, such as deficits in learning, memory and cognition and Alzheimer's disease are associated with diabetes mellitus. Brain-derived neurotrophic factor (BDNF) is a neurotrophic factor and is known to possess anti-obesity, anti-diabetic actions and is believed to have a role in memory and Alzheimer's disease.

OBJECTIVE

To investigate whether STZ can reduce BDNF production by rat insulinoma (RIN5F) cells in vitro and decrease BDNF levels in the pancreas, liver and brain in vivo.

METHODS

Streptozotocin (STZ)-induced cytotoxicity to RIN5F cells in vitro and type 2 DM in Wistar rats was employed in the present study. Cell viability, activities of various anti-oxidants and secretion of BDNF by RIN5F cells in vitro were measured using MTT assay, biochemical methods and ELISA respectively. In STZ-induced type 2 DM rats: plasma glucose, interleukin-6 and tumor necrosis factor-α levels and BDNF protein expression in the pancreas, liver and brain tissues were measured. In addition, neuronal count and morphology in the hippocampus and hypothalamus areas was assessed.

RESULTS

STZ-induced suppression of RIN5F cell viability was abrogated by BDNF. STZ suppressed BDNF secretion by RIN5F cells in vitro. STZ-induced type 2 DM rats showed hyperglycemia, enhanced plasma IL-6 and TNF-αlevels and reduced plasma and pancreas, liver and brain tissues (P < 0.001) and increased oxidative stress compared to untreated control. Hypothalamic and hippocampal neuron in STZ-treated animals showed a decrease in the number of neurons and morphological changes suggesting of STZ cytotoxicity.

CONCLUSIONS

The results of the present study suggest that STZ is not only cytotoxic to pancreatic beta cells but also to hypothalamic and hippocampal neurons by inducing oxidative stress. STZ ability to suppress BDNF production by pancreas, liver and brain tissues suggests that impaired memory, learning, and cognitive dysfunction seen in diabetes mellitus could be due to BDNF deficiency.

Involvement of AMPK in regulating the degradation of MAD2B under high glucose in neuronal cells

Although our recent study has demonstrated that mitotic spindle assembly checkpoint protein (MAD2B) mediates high glucose‐induced neuronal apoptosis, the mechanisms for MAD2B degradation under hyperglycaemia have not yet been elucidated. In this study, we first found that the activation of adenosine 5′‐monophosphate (AMP)‐activated protein kinase (AMPK) was decreased in neurons, accompanied with the increased expression of MAD2B. Mechanistically, we demonstrated that activation of AMPK with its activators such as AICAR and metformin decreased the expression of MAD2B, indicating a role of AMPK in regulating the expression of MAD2B. Moreover, activation of AMPK prevented neuronal cells from high glucose‐induced injury as demonstrated by the reduced expression of cyclin B1 and percentage of apoptosis as detected by TUNEL. We further found that when total protein synthesis was suppressed by chlorhexidine, the degradation of MAD2B was slower in high glucose‐treated neurons and was mainly dependent on the ubiquitin–proteasome system. Finally, it was indicated that high glucose inhibited the ubiquitination of MAD2B, which could be reversed by activation of AMPK. Collectively, this study demonstrates that AMPK acts as a key regulator of MAD2B expression, suggesting that activation of AMPK signalling might be crucial for the treatment of high glucose‐induced neuronal injury.