Punicalagin Attenuates Neuronal Apoptosis by Upregulating 5-Hydroxymethylcytosine in the Diabetic Mouse Brain

Fucoidan prevents diabetic cognitive dysfunction via promoting TET2-mediated active DNA demethylation in high-fat diet induced diabetic mice

Diabetic cognitive dysfunction (DCD) refers to cognitive impairment in individuals with diabetes, which is one of the most important comorbidities and complications. Preliminary evidence suggests that consuming sufficient dietary fiber could have benefits for both diabetes and cognitive function. However, the effect and underlying mechanism of dietary fiber on DCD remain unclear. We conducted a cross-sectional analysis using data from NHANES involving 2072 diabetics and indicated a significant positive dose-response relationship between the dietary fiber intake and cognitive performance in diabetics. Furthermore, we observed disrupted cognitive function and neuronal morphology in high-fat diet induced DCD mice, both of which were effectively restored by fucoidan supplementation through alleviating DNA epigenetic metabolic disorders. Moreover, fucoidan supplementation enhanced the levels of short-chain fatty acids (SCFAs) in the cecum of diabetic mice. These SCFAs enhanced TET2 protein stability by activating phosphorylated AMPK and improved TETs activity by reducing the ratio of (succinic acid + fumaric acid)/ α-ketoglutaric acid, subsequently enhancing TET2 function. The positive correlation between dietary fiber intake and cognitive function in diabetics was supported by human and animal studies alike. Importantly, fucoidan can prevent the occurrence of DCD by promoting TET2-mediated active DNA demethylation in the cerebral cortex of diabetic mice.

Multifaceted Neuroprotective Role of Punicalagin: A Review

Millions of people worldwide are currently afflicted with neurologic conditions like a seizure, depression, stress, Alzheimer's disease, Parkinson's disease, and Huntington's disease. However, the precise etiopathology of these diseases is still unknown. Substantial studies are being conducted to discover more treatments against these disorders because many patients do not experience the therapeutic benefits that would be expected from using existing pharmaceutical strategies. Herbal medicines which have been used in traditional medicine for millennia to treat various neurological problems are also being investigated and scientifically assessed. Punicalagin is a known polyphenol that has significant antioxidant, anti-inflammatory, anti-viral, anti-proliferative, and anti-cancer properties. Around the world, traditional use of herbal drugs is gaining wider acceptance as a part of complementary and alternative medicine. The scientific community should pay attention to these many neuroprotective pharmacodynamic activities of Punicalagin to create effective pharmacotherapeutic plans, as evidenced by mounting data in pre-clinical research investigations. The current review describes the recent studies on the pharmacological effects of Punicalagin in a variety of neurological illnesses and paves the way for further study in this field.

Tracheal regeneration and mesenchymal stem cell augmenting potential of natural polyphenol-loaded gelatinmethacryloyl bioadhesive

Hydrogels incorporating natural biopolymer and adhesive substances have extensively been used to develop bioactive drugs and to design cells encapsulating sturdy structure for biomedical applications. However, the conjugation of the adhesive in most hydrogels is insufficient to maintain long-lasting biocompatibility inadequate to accelerate internal organ tissue repair in the essential native cellular microenvironment. The current work elaborates the synthesis of charged choline-catechol ionic liquid (BIL) adhesive and a hydrogel with an electronegative atom rich polyphenol (PU)-laden gelatinmethacryloyl (GelMA) to improve the structural bioactivities for in vivo tracheal repair by inducing swift crosslinking along with durable mechanical and tissue adhesive properties. It was observed that bioactive BIL and PU exhibited potent antioxidant (IC 50 % of 7.91 μg/mL and 24.55 μg/mL) and antibacterial activity against E. coli, P. aeruginosa and S. aureus. The novel integration of photocurable GelMA-BIL-PU revealed outstanding mechanical strength, biodegradability and sustained drug release. The in vitro study showed exceptional cell migration and proliferation in HBECs, while in vivo investigation of the GelMA-BIL-PU hydrogel on a rat's tracheal model revealed remarkable tracheal reconstruction, concurrently reducing tissue inflammation. Furthermore, the optimized GelMA-BIL-PU injectable adhesive bioink blend demonstrated superior MSCs migration and proliferation, which could be a strong candidate for developing stem cell-rich biomaterials to address multiple organ defects.

Fucoidan Improves Early Stage Diabetic Nephropathy via the Gut Microbiota-Mitochondria Axis in High-Fat Diet-Induced Diabetic Mice

Diabetic nephropathy (DN) is a common microvascular complication of diabetes. Fucoidan, a polysaccharide containing fucose and sulfate group, ameliorates DN. However, the underlying mechanism has not been fully understood. This study aimed to explore the effects and mechanism of fucoidan on DN in high-fat diet-induced diabetic mice. A total of 90 C57BL/6J mice were randomly assigned to six groups (n = 15) as follows: normal control (NC), diabetes mellitus (DM), metformin (MTF), low-dose fucoidan (LFC), medium-dose fucoidan (MFC), and high-dose fucoidan (HFC). A technique based on fluorescein isothiocyanate (FITC-sinistin) elimination kinetics measured percutaneously was applied to determine the glomerular filtration rate (GFR). After 24 weeks, the mice were sacrificed and an early stage DN model was confirmed by GFR hyperfiltration, elevated urinary creatinine, normal urinary albumin, tubulointerstitial fibrosis, and glomerular hypertrophy. Fucoidan significantly improved the GFR hyperfiltration and renal fibrosis. An enriched SCFAs-producing bacteria and increased acetic concentration in cecum contents were found in fucoidan groups, as well as increased renal ATP levels and improved mitochondrial dysfunction. The renal inflammation and fibrosis were ameliorated through inhibiting the MAPKs pathway. In conclusion, fucoidan improved early stage DN targeting the microbiota-mitochondria axis by ameliorating mitochondrial oxidative stress and inhibiting the MAPKs pathway.

Thinned young apple powder prevents obesity-induced neuronal apoptosis via improving mitochondrial function of cerebral cortex in mice

Mitochondrial dysfunction is one of the triggers for obesity-induced neuron apoptosis. Thinned young apple is getting more attention on account of the extensive biological activities because of rich polyphenols and polysaccharides. However, the neuroprotective effect of thinned young apple powder (YAP) is still unclear. The aim of the present study was to investigate the preventive effect of YAP on obesity-induced neuronal apoptosis. C57BL/6J male mice were divided into 5 groups, control (CON), high fat diet (HFD), HFD + orlistat (ORL), HFD + low-dose young apple powder (LYAP) and HFD + high-dose young apple powder (HYAP) groups and intervened for 12 weeks. It was found that the YAP effectively reduced body weight gain. Importantly, the levels of pro-apoptosis protein were lower in LYAP and HYAP groups than the HFD group, such as Bak/Bcl2 and cleaved caspase3/caspase3. Pathway analysis based on untargeted metabolomics suggested that YAP alleviated obesity-induced neuronal apoptosis by three main metabolic pathway including arginine metabolism, citrate cycle (TCA cycle) and glutathione metabolism. Meanwhile, YAP improved the protein expression of mitochondrial respiratory chain complex, maintained the homeostasis of TCA cycle intermediates, protected the balance of mitochondrial dynamics and alleviated lipid accumulation. In addition, the levels of several antioxidants in cerebral cortex were higher in HYAP group than the HFD group like superoxide dismutase (SOD) and catalase (CAT). In summary, YAP supplementation suppressed neuronal apoptosis in the cerebral cortex of HFD-induced obesity mice by improving mitochondrial function and inhibiting oxidative stress.

Punicalagin protects against impaired skeletal muscle function in high-fat-diet-induced obese mice by regulating TET2

The function of skeletal muscles can be markedly hampered by obesity. Ten-eleven translocation 2 (TET2) is an important therapeutic target for ameliorating skeletal muscle dysfunction. Our previous study revealed that punicalagin (PUN) regulated TET2 in obese mice; however, whether PUN can prevent obesity-induced skeletal muscle dysfunction by regulating TET2 remains unclear. In the present study, 40 male C57BL/6J mice were divided into four groups (n = 10 per group): the control (CON) group, the high-fat-diet (HFD, negative control) group, the resveratrol (positive control) group, and the PUN group. The ratio of gastrocnemius weight to body weight (0.0097 ± 0.0016 vs. 0.0080 ± 0.0011), the grip strength (120.04 g ± 11.10 vs. 98.89 g ± 2.79), and the muscle fiber count (314.56 per visual field ± 92.73 vs. 236.44 per visual field ± 50.58) in the PUN group were higher than those in the HFD group. Moreover, the levels of the TET2 protein, 5-hydroxymethylcytosine (5hmC), and 5-formylcytosine (5fC) in skeletal muscles were significantly lower in the HFD group than those in the CON group; these levels increased after PUN treatment. Compared with the HFD group, the phosphorylation level of AMP-activated protein kinase (AMPK) α in the PUN group was higher, which effectively enhanced the stability of the TET2 protein. Besides, the ratio of (succinic acid + fumaric acid)/α-ketoglutarate in the PUN group was lower than that in the HFD group (43.21 ± 12.42 vs. 99.19 ± 37.07), and a lower ratio led to a higher demethylase activity of TET2 in the PUN group than in the HFD group. This study highlights that PUN supplementation protects against obesity-induced impairment of the skeletal muscle function via regulating the protein stability of TET2 and the enzymatic activity of TET2 demethylation.

Dendrobium officinale polysaccharide prevents neuronal apoptosis via TET2-dependent DNA demethylation in high-fat diet-induced diabetic mice

Dendrobium officinale polysaccharide (DP) has the potential function to prevent diabetes-induced neuronal apoptosis, whereas the mechanism is not completely clear. Ten eleven translocation dioxygenase 2 (TET2) is one of the most important therapeutic target for repairing neuronal damage in diabetic mice. The aim of the present study was to investigate whether DP could prevent neuronal apoptosis by regulating TET2 in the brain of HFD-induced diabetic mice. C57BL/6J mice were randomly divided into four groups (n = 12), control group (CON), high-fat diet group (HFD, negative control), metformin group (MET, positive control), and DP group (DP). Compared with HFD group, the neuronal apoptosis of brain was significantly lower in the DP group. The levels of TET2 protein, 5-hydroxymethylcytosine (5hmC) and 5-formylcytosine (5fC) were significantly lower in the HFD group than in both the DP and CON groups in the cerebral cortex of mice. The ratio of p-AMPK/AMPK and α-KG/(fumaric acid + succinic acid) were significantly lower in the HFD group than in the other groups. The present study suggests that DP has a preventive effect on diabetes-induced neuronal apoptosis by regulating TET2 function through improving phosphorylate AMPK and mitochondrial function, thus remodeling DNA epigenetics profile of mice brain.

Thinned young apple polyphenols may prevent neuronal apoptosis by up-regulating 5-hydroxymethylcytosine in the cerebral cortex of high-fat diet-induced diabetic mice

Apple polyphenols exert neuroprotective effects by improving the mitochondrial tricarboxylic acid (TCA) cycle function, but the details of their mechanisms are still not fully understood. TCA cycle metabolites regulate the level of 5-hydroxymethylcytosine (5hmC) by affecting the ten-eleven translocation (TET) enzyme activity. Therefore, we hypothesized that thinned young apple polyphenols (TYAPs) inhibit neuronal apoptosis by up-regulating the level of 5hmC in the cerebral cortex of high-fat diet-induced diabetic mice. C57BL/6J mice were randomly divided into 5 groups (n = 10 each group): the control (CON) group, the high-fat diet (HFD, negative control) group, the lovastatin (LOV, positive drug control) group, the resveratrol (RES, positive polyphenol control) group and the TYAP group during an eight-week intervention. The presented results verified that in the HFD group, the level of 5hmC and the expression of TET2 in the cerebral cortex were significantly lower, and the ratio of (succinic acid + fumaric acid)/α-ketoglutarate and the neuronal apoptosis rate were significantly higher than those in the CON group. However, TYAP intervention effectively restored the level of 5hmC through up-regulating the expression and activity of TET2, so as to improve diabetes symptoms and prevent diabetes-induced neuronal apoptosis.

Fingolimod Alleviates Cognitive Deficit in Type 2 Diabetes by Promoting Microglial M2 Polarization via the pSTAT3-jmjd3 Axis

Sphingosine receptors (S1PRs) are implicated in the progression of neurodegenerative diseases and metabolic disorders like obesity and type 2 diabetes (T2D). The link between S1PRs and cognition in type 2 diabetes, as well as the mechanisms that underpin it, are yet unknown. Neuroinflammation is the common pathology shared among T2D and cognitive impairment. However, the interplay between the M1 and M2 polarization state of microglia, a primary driver of neuroinflammation, could be the driving factor for impaired learning and memory in diabetes. In the present study, we investigated the effects of fingolimod (S1PR1 modulator) on cognition in high-fat diet and streptozotocin-induced diabetic mice. We further assessed the potential pathways linking microglial polarization and cognition in T2D. Fingolimod (0.5 mg/kg and 1 mg/kg) improved M2 polarization and synaptic plasticity while ameliorating cognitive decline and neuroinflammation. Sphingolipid dysregulation was mimicked in vitro using palmitate in BV2 cells, followed by conditioned media exposure to Neuro2A cells. Mechanistically, type 2 diabetes induced microglial activation, priming microglia towards the M1 phenotype. In the hippocampus and cortex of type 2 diabetic mice, there was a substantial drop in pSTAT3, which was reversed by fingolimod. This protective effect of fingolimod on microglial M2 polarization was primarily suppressed by selective jmjd3 blockade in vitro using GSK-J4, revealing that jmjd3 was involved downstream of STAT3 in the fingolimod-enabled shift of microglia from M1 to M2 polarization state. This study suggested that fingolimod might effectively improve cognition in type 2 diabetes by promoting M2 polarization.

Reprogramming of ovarian aging epigenome by resveratrol

Resveratrol is an antiaging, antioxidant, and anti-inflammatory natural polyphenolic compound. Growing evidence indicates that resveratrol has potential therapeutic effects for improving aging ovarian function. However, the mechanisms underlying prolonged reproductive longevity remain elusive. We found that resveratrol ameliorates ovarian aging transcriptome, some of which are associated with specific changes in methylome. In addition to known aging transcriptome of oocytes and granulosa cells such as decline in oxidoreductase activity, metabolism and mitochondria function, and elevated DNA damage and apoptosis, actin cytoskeleton are notably downregulated with age, and these defects are mostly rescued by resveratrol. Moreover, the aging-associated hypermethylation of actin cytoskeleton is decreased by resveratrol. In contrast, deletion of Tet2, involved in DNA demethylation, abrogates resveratrol-reprogrammed ovarian aging transcriptome. Consistently, Tet2 deficiency results in additional altered pathways as shown by increased mTOR and Wnt signaling, as well as reduced DNA repair and actin cytoskeleton with mouse age. Moreover, genes associated with oxidoreductase activity and oxidation-reduction process were hypermethylated in Tet2-deficient oocytes from middle-age mice treated with resveratrol, indicating that loss of Tet2 abolishes the antioxidant effect of resveratrol. Taking together, our finding provides a comprehensive landscape of transcriptome and epigenetic changes associated with ovarian aging that can be reprogrammed by resveratrol administration, and suggests that aberrantly increased DNA methylation by Tet2 deficiency promotes additional aging epigenome that cannot be effectively restored to younger state by resveratrol.

Microbiota from Exercise Mice Counteracts High-Fat High-Cholesterol Diet-Induced Cognitive Impairment in C57BL/6 Mice

Gut microbes may be the critical mediators for the cognitive enhancing effects of exercise. Via fecal microbiota transplantation (FMT), this study is aimed at determining the mechanism of how voluntary exercise improved learning and memory ability impairment post a high-fat, high-cholesterol (HFHC) diet. The learning and memory abilities assessed via the Morris water maze in the FMT recipient group of voluntary exercising mice were improved compared to sedentary group. 16S rRNA gene sequencing results indicated that exercise-induced changes in gut microbiota distribution were transmissible, mainly in terms of elevated Lactobacillus, Lactobacillus, and Eubacterium nodatum, as well as decreased Clostrida_UCG-014 and Akkermansia after FMT. The neuroprotective effects of FMT were mainly related to the improved insulin signaling pathway (IRS2/PI3K/AKT) and mitochondrial function; inhibition of AQP4; decreased p-Tau at serine 396 and 404; increased BDNF, PSD95, and synaptophysin in the hippocampus; and also decreased HDAC2 and HDAC3 protein expressions in the nuclear and cytoplasmic fractions of the hippocampus. The findings of qRT-PCR suggested that exercise-induced gut microbes, on the one hand, elevated GPR109A and decreased GPR43 and TNF-α in the hippocampus. On the other hand, it increased GPR109A and GPR41 expressions in the proximal colon tissue. In addition, total short-chain fatty acid (SCFA), acetic acid, propionic acid, isobutyric acid, valeric acid, and isovaleric acid contents were also elevated in the cecum. In conclusion, exercise-induced alterations in gut microbiota play a decisive role in ameliorating HFHC diet-induced cognitive deficits. FMT treatment may be a new considerable direction in ameliorating cognitive impairment induced by exposure to HFHC diet.

Protective effects of apple polyphenols on bone loss in mice with high fat diet-induced obesity

Obesity-induced inflammation can lead to an imbalance in bone formation and resorption. Our previous studies have demonstrated that apple polyphenols (AP) can reduce body weight and inflammation. But its effect...