Cyclic Nucleotide Phosphodiesterases in Alcohol Use Disorders: Involving Gut Microbiota.

Alcohol abuse is 1 of the most significant public health problems in the world. Chronic, excessive alcohol consumption not only causes alcohol use disorder (AUD) but also changes the gut and lung microbiota, including bacterial and nonbacterial types. Both types of microbiota can release toxins, further damaging the gastrointestinal and respiratory tracts; causing inflammation; and impairing the functions of the liver, lung, and brain, which in turn deteriorate AUD. Phosphodiesterases (PDEs) are critical in the control of intracellular cyclic nucleotides, including cyclic adenosine monophosphate and cyclic guanosine monophosphate. Inhibition of certain host PDEs reduces alcohol consumption and attenuates alcohol-related impairment. These PDEs are also expressed in the microbiota and may play a role in controlling microbiota-associated inflammation. Here, we summarize the influences of alcohol on gut/lung bacterial and nonbacterial microbiota as well as on the gut-liver/brain/lung axis. We then discuss the relationship between gut and lung microbiota-mediated PDE signaling and AUD consequences in addition to highlighting PDEs as potential targets for treatment of AUD.

GABAergic System in Stress: Implications of GABAergic Neuron Subpopulations and the Gut-Vagus-Brain Pathway.

Stress can cause a variety of central nervous system disorders, which are critically mediated by the γ-aminobutyric acid (GABA) system in various brain structures. GABAergic neurons have different subsets, some of which coexpress certain neuropeptides that can be found in the digestive system. Accumulating evidence demonstrates that the gut-brain axis, which is primarily regulated by the vagus nerve, is involved in stress, suggesting a communication between the "gut-vagus-brain" pathway and the GABAergic neuronal system. Here, we first summarize the evidence that the GABAergic system plays an essential role in stress responses. In addition, we review the effects of stress on different brain regions and GABAergic neuron subpopulations, including somatostatin, parvalbumin, ionotropic serotonin receptor 5-HT3a, cholecystokinin, neuropeptide Y, and vasoactive intestinal peptide, with regard to signaling events, behavioral changes, and pathobiology of neuropsychiatric diseases. Finally, we discuss the gut-brain bidirectional communications and the connection of the GABAergic system and the gut-vagus-brain pathway.

(-)-Epigallocatechin-3-gallate attenuates cognitive deterioration in Alzheimer's disease model mice by upregulating neprilysin expression.

Epigenetic changes are involved in learning and memory, and histone deacetylase (HDAC) inhibitors are considered potential therapeutic agents for Alzheimer's disease (AD). We previously reported that (-)-epigallocatechin-3-gallate (EGCG) acts as an HDAC inhibitor. Here, we demonstrate that EGCG reduced ß-amyloid (Aß) accumulation in vitro and rescued cognitive deterioration in senescence-accelerated mice P8 (SAMP8) via intragastric administration of low- and high-dose EGCG (5 and 15 mg/kg, respectively) for 60 days. The AD brain has decreased levels of the rate-limiting degradation enzyme of Aß, neprilysin (NEP). We found an association between EGCG-induced reduction in Aß accumulation and elevated NEP expression. Further, NEP silencing prevented the EGCG-induced Aß downregulation. Our findings suggest that EGCG might be effective for treating AD.

Chinese medicine PaBing-II protects human iPSC-derived dopaminergic neurons from oxidative stress.

Background: PaBing-II Formula (PB-II) is a traditional Chinese medicine for treating Parkinson's disease (PD). However, owing to the complexity of PB-II and the difficulty in obtaining human dopaminergic neurons (DAn), the mechanism of action of PB-II in PD treatment remains unclear. The aim of this study was to investigate the mechanisms underlying the therapeutic benefits of PB-II in patients with PD. Methods: hiPSCs derived DAn were treated with H2O2 to construct the DAn oxidative damage model. SwissTargetPrediction was employed to predict the potential targets of the main compounds in serum after PB-II treatment. Metascape was used to analyze the pathways. Sprague-Dawley rats were used to construct the 6-hydroxydopamine (6-OHDA)-induced PD model, and the duration of administration was four weeks. RNA sequencing was used for Transcriptome analysis to find the signal pathways related to neuronal damage. The associated inflammatory factors were detected by enzyme-linked immunosorbent assay (ELISA). We identified PB-II as an Nrf2 activator using antioxidant-responsive element luciferase assay in MDA-MB-231 cells. Results: In vitro experiments showed that the treatment of PB-II-treated serum increased the percentage of TH+ cells, decreased inflammation and the apoptosis, reduced cellular reactive oxygen species, and upregulated the expression of Nrf2 and its downstream genes. Pathway analysis of the RNA-seq data of samples before and after the treatment with PB-II-treated serum identified neuron-associated pathways. In vivo experiments demonstrated that PB-II treatment of PD rat model could activate the Nrf2 signaling pathway, protect the midbrain DAn, and improve the symptoms in PD rats. Conclusion: PB-II significantly protects DAn from inflammation and oxidative stress via Nrf2 pathway activation. These findings elucidate the roles of PB-II in PD treatment and demonstrate the application of hiPSC-derived DAn in research of Chinese medicine.

SLC2A9 rs16890979 reduces uric acid absorption by kidney organoids.

Introduction: The excretion and absorption of uric acid (UA) by the kidneys helps regulate serum UA levels. GLUT9, encoded by SLC2A9, is mainly expressed in the renal tubules responsible for UA absorption. SLC2A9 polymorphisms are associated with different serum UA levels. However, the lack of proper in vitro models has stalled research on the mechanisms of single nucleotide polymorphisms (SNPs) that affect UA metabolism in human urate transporters. Methods: In this study, we constructed a gene-edited human embryonic stem cells-9 (ESC-H9) derived kidney organoid bearing rs16890979, an SLC2A9 missense mutation with undetermined associations with hyperuricemia or hypouricemia. Kidney organoids derived from ESC-H9 with genetical overexpression (OE) and low expression (shRNA) of SLC2A9 to serve as controls to study the function of SLC2A9. The function of rs16890979 on UA metabolism was evaluated after placing the organoids to urate-containing medium and following histopathological analysis. Results: The kidney organoids with heterozygous or homozygous rs16890979 mutations showed normal SLC2A9 expression levels and histological distribution, phenotypically similar to the wild-type controls. However, reduced absorption of UA by the kidney organoids with rs16890979 mutants was observed. This finding together with the observation that UA absorption is increased in organoids with SLC2A9 overexpression and decreased in those with SLC2A9 knockdown, suggest that GLUT9 is responsible for UA absorption, and the rs16890979 SNP may compromise this functionality. Moreover, epithelial-mesenchymal transition (EMT) was detected in organoids after UA treatment, especially in the kidney organoid carrying GLUT9OE, suggesting the cytobiological mechanism explaining the pathological features in hyperuricosuria-related renal injury. Discussion: This study showing the transitional value of kidney organoid modeling the function of SNPs on UA metabolism. With a defined genetic background and a confirmed UA absorption function should be useful for studies on renal histological, cellular, and molecular mechanisms with this organoid model.

Two Sets of Compound Complex Driving for High Efficiency of Nonintegration Reprogramming of Human Fibroblasts.

Currently, plentiful chemical-assisted methods have been applied for mouse induced pluripotent stem cells (iPSCs). It has been reported that small-molecule compounds can only reprogram mouse embryonic fibroblasts into mouse chemically induced pluripotent stem cells (mouse CiPSCs). However, human CiPSCs have not been reported. Therefore, it is still necessary to search for safer chemically assisted human pluripotent stem cells, which might realize the potential of human iPSCs. Here, we developed two sets of chemical cocktails to greatly improve the induction efficiency of human nonintegrated iPSCs, including the 4 compound mixture (4M) and the 5 compound mixture (4MI). These two sets of complex driving strategies might greatly improve the reprogramming efficiency to generate integration-free iPSCs.

A strategy for iron oxide nanoparticles to adhere to the neuronal membrane in the substantia nigra of mice.

Effective attachment of magnetic nanoparticles to neuronal membranes has far-reaching significance in activating ion channels and treating neurodegenerative diseases. Superparamagnetic iron oxide nanoparticles (SPIONs) synthesized by the polyol pyrolysis method have the advantages of rich surface functional groups, excellent magnetic properties, controllable particle size and water dispersibility. We propose that perfusion of biotin into the targeted brain area should be initially performed because it tends to be adsorbed by cell membranes, followed by injection of streptavidin (SA)-modified SPIONs into the same area of the brain. By means of the strong binding force between SA and biotin, the SPIONs may subsequently adhere to the cell surfaces in the brain area. In this work, fluorescein isothiocyanate-streptavidin (FITC-SA) was modified on the surface of polyethylene imine (PEI)-SPIONs by the EDC-NHS method and stereotaxically injected into the biotin-supplemented substantia nigra of mice. The combination of fluorescence detection with transmission electron microscopy (TEM) confirmed that FITC-SA/PEI-SPIONs adhered to neuronal membranes in the substantia nigra of mice 24 h after injection. The results show that our strategy can promote the attachment of SPIONs to neuronal membranes.

Neuroprotective Effect of Optimized Yinxieling Formula in 6-OHDA-Induced Chronic Model of Parkinson's Disease through the Inflammation Pathway.

Parkinson's disease (PD) is characterized by progressive degeneration of dopaminergic neurons in the substantia nigra (SN)-striatum circuit, which is associated with glial activation and consequent chronic neuroinflammation. Optimized Yinxieling Formula (OYF) is a Chinese medicine that exerts therapeutical effect and antiinflammation property on psoriasis. Our previous study has proven that pretreatment with OYF could regulate glia-mediated inflammation in an acute mouse model of PD induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Given that PD is a chronic degeneration disorder, this study applied another PD animal model induced by striatal injection of 6-hydroxydopamine (6-OHDA) to mimic the progressive damage of the SN-striatum dopamine system in rats. The OYF was administrated in the manner of pretreatment plus treatment. The effects of the OYF on motor behaviors were assessed with the apomorphine-induced rotation test and adjusting steps test. To confirm the effect of OYF on dopaminergic neurons and glia activation in this model, we analyzed the expression of tyrosine hydroxylase (TH) and glia markers, ionized calcium-binding adapter molecule 1 (Iba-1), and glial fibrillary acidic protein (GFAP) in the SN region of the rat PD model. Inflammation-associated factors, including tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), IL-6, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2), were further evaluated in this model and in interferon-γ- (INF-γ-) induced murine macrophages RAW264.7 cells. The results from the in vivo study showed that OYF reversed the motor behavioral dysfunction in 6-OHDA-induced PD rats, upregulated the TH expression, decreased the immunoreactivity of Iba-1 and GFAP, and downregulated the mRNA levels of TNF-α and COX-2. The OYF also trended to decrease the mRNA levels of IL-1ß and iNOS in vivo. The results from the in vitro study showed that OYF significantly decreased the mRNA levels of TNF-α, IL-1ß, IL-6, iNOS, and COX-2. Therefore, this study suggests that OYF exerts antiinflammatory effects, which might be related to the protection of dopaminergic neurons in 6-OHDA-induced chronic neurotoxicity.

Using the synthesized peptide HAYED (5) to protect the brain against iron catalyzed radical attack in a naturally senescence Kunming mouse model.

Alzheimer's disease (AD) is a progressive neurodegenerative disease of the brain. It cannot be cured currently, and those suffering from AD place a great burden on their caregivers and society. AD is characterized by high levels of iron ions in the brain, which catalyze radicals that damage the neurons. Knowing that the Aß42 peptide precipitates iron by binding iron ions at amino acid residues D1, E3, H11, H13, and H14, we synthesized a 5-repeat (HAYED) sequence peptide. By treating iron-stressed SH-SY5Y cells with it and injecting it into the cerebrospinal fluid (CSF) of naturally senescence Kunming mouse, which displaying AD-similar symptoms such as learning and memory dysfunction, neuron degeneration and high level of iron in brain, we found that HAYED (5) decreased the iron and radical levels in the cell culture medium and in the CSF. Specially, the synthesized peptide prevented cell and brain damage. Furthermore, functional magnetic resonance imaging (fMRI), Morris water maze and passive avoidance tests demonstrated that the peptide ameliorated brain blood-oxygen metabolism and slowed cognitive loss in the experimental senescence mice, and clinical and blood tests showed that HAYED (5) was innoxious to the kidney, the liver and blood and offset the AD-associated inflammation and anemia.

(-)-Epigallocatechin-3-gallate induces cancer cell apoptosis via acetylation of amyloid precursor protein.

Epigenetic modifications are involved in cancer pathogenesis, and HDACis are considered potential therapeutic agents. We and others have shown the inhibitory activity of EGCG on HDAC1. But little is known about the effect of EGCG as on epigenetic regulation in cancer. Here, we try to demonstrate that EGCG acts as an HDACi downregulated APP expression, which was pathophysiologically upregulated in cancers and exerts a key role in cancer cell growth. We used PC-12 cells, SK-N-SH cells and primary tumor tissues for our analysis. Male 4-week-old athymic nude mice were used for heterotopic tumor growth assay. We employed Western blotting analysis to detect Bcl-2, Bax, APP, caspase-3, caspase-7, HDAC1 and H4Ac. We used AnnexinV-FITC and TUNEL staining for apoptosis detection. Tumor tissues were examined by immunohistochemical staining. We demonstrated that EGCG suppresses the growth of xenografted adrenal pheochromocytoma. Flow cytometry analysis and TUNEL staining showed that EGCG induced the apoptosis. Treatment with EGCG resulted in decrease in Bcl-2 but increase in Bax and activated caspase-3 and caspase-7. HDAC inhibitor EGCG leaded to hyperacetylated histone H4 by immunofluorescence. EGCG decreased APP levels by immunofluorescence staining and Western blot analysis. Silencing specific to HDAC1 leaded to caspase-3 and caspase-7 activation and cleavage. Our results are the first to demonstrate a functional interaction between EGCG and APP in suppression tumor growth, and provide a new epigenetic effects of EGCG on antitumor.

Alleviating effects of Bushen-Yizhi formula on ibotenic acid-induced cholinergic impairments in rat.

This study explored the curative effect and underlying mechanisms of a traditional Chinese medicine compound prescription, Bushen-Yizhi formula (BSYZ), in ibotenic acid (IBO)-induced rats. Morris water maze and novel object recognition tests showed that BSYZ significantly improved spatial and object memory. Brain immunohistochemistry staining showed that BSYZ significantly up-regulated expression of choline acetyltransferase (ChAT) and nerve growth factor (NGF) in the hippocampus and cortex. The protein tyrosine kinase high-affinity receptor TrkA was slightly increased in the hippocampus and cortex, and significantly enhanced in the nucleus basalis of Meynert (NBM) after BSYZ intervention. The immunoreactivity of the p75 low-affinity receptor in BSYZ-treated rats was significantly strengthened in the cortex. Similar expression trends of nerve growth factor (NGF), TrkA, and p75 mRNA were observed in the hippocampus and cortex. Additionally, BSYZ reversed IBO-induced disorders of acetylcholine (ACh) levels, ChAT, and cholinesterase (ChE) in the cortex, which was consistent with the changes in mRNA levels of ChAT and acetylcholinesterase (AChE). Expression of ChAT and AChE proteins and mRNA in the hippocampus was up-regulated, whereas the apoptosis-relative protein cleaved caspase-3 was decreased after administration of BSYZ. Moreover, changes in cell death were confirmed by histological morphology. Thus, the results indicated that the BSYZ formula could ameliorate memory impairments in IBO-induced rats, and it exerted its therapeutic action probably by modulating cholinergic pathways, NGF signaling, and anti-apoptosis. Overall, it is suggested that the BSYZ formula might be a potential therapeutic approach for the treatment of Alzheimer's disease (AD) and other cholinergic impairment-related diseases.

Bushen­Yizhi formula ameliorates cognition deficits and attenuates oxidative stress­related neuronal apoptosis in scopolamine­induced senescence in mice.

Bushen­Yizhi formula (BSYZ), a traditional Chinese medicine formula consisting of six herbs has been reported to possess a neuroprotective effect. The present study aimed to investigate the effects of BSYZ on learning and memory abilities, as well as oxidative stress and neuronal apoptosis in the hippocampus of scopolamine (SCOP)­induced senescence in mice, in order to reveal whether BSYZ is a potential therapeutic agent for Alzheimer's disease (AD). A high­performance liquid chromatography (HPLC) fingerprint was applied to provide a chemical profile of BSYZ. Extracts of BSYZ were orally administered to mice with SCOP­induced memory impairment for two weeks. The learning and memory abilities were determined by the Morris water maze test. The oxidant stress­related indices, such as activity of superoxide dismutase (SOD) and levels of glutathione (GSH) and malondialdehyde (MDA) were examined in hippocampus of SCOP­treated mice. The cell death ratio was assessed by TUNEL staining, while apoptotic­related proteins including Bcl­2 and Bax were determined by immuno-fluorescent staining and western blot analysis. Caspase­3 was determined by western blot analysis. Consequently, a chromatographic condition, which was conducted at 35˚C with a flow rate of 0.8 ml/min on the Gemini C18 column with mobile phase of acetonitrile and water­phosphoric acid (100:0.1, v/v), was established to yield common fingerprint chromatography under 203 nm with a similarity index of 0.986 within 10 batches of BSYZ samples. BSYZ at a dose of 2.92 g/kg significantly improved the cognitive ability, restored the abnormal activity of SOD and increased the levels of MDA and GSH induced by SCOP. Moreover, the neural apoptosis in the hippocampus of SCOP­treated mice was reversed by BSYZ by regulating the expression of Bcl­2, Bax and caspase­3. The results demonstrated that BSYZ had neuroprotective effects in SCOP­induced senescence in mice by ameliorating oxidative stress and neuronal apoptosis in the brain, supporting its potential in AD treatment.