Aging-associated REGγ proteasome decline predisposes to tauopathy.

The REGγ-20S proteasome is an ubiquitin- and ATP-independent degradation system, targeting selective substrates, possibly helping to regulate aging. The studies we report here demonstrate that aging-associated REGγ decline predisposes to decreasing tau turnover, as in a tauopathy. The REGγ proteasome promotes degradation of human and mouse tau, notably phosphorylated tau and toxic tau oligomers that shuttle between the cytoplasm and nuclei. REGγ-mediated proteasomal degradation of tau was validated in 3- to 12-month-old REGγ KO mice, REGγ KO;PS19 mice, and PS19 mice with forebrain conditional neuron-specific overexpression of REGγ (REGγ OE) and behavioral abnormalities. Coupled with tau accumulation, we found with REGγ-deficiency, neuron loss, dendrite reduction, tau filament accumulation, and microglial activation are much more prominent in the REGγ KO;PS19 than the PS19 model. Moreover, we observed that the degenerative neuronal lesions and aberrant behaviors were alleviated in REGγ OE;PS19 mice. Memory and other behavior analysis substantiate the role of REGγ in prevention of tauopathy-like symptoms. In addition, we investigated the potential mechanism underlying aging-related REGγ decline. This study provides valuable insights into the novel regulatory mechanisms and potential therapeutic targets for tau-related neurodegenerative diseases.

Role of epoxyeicosatrienoic acids in cardiovascular diseases and cardiotoxicity of drugs.

Epoxyeicosatrienoic acids (EETs) are important endogenous substances that affect heart function in human body. Animal models of cytochrome P450 (CYP) and soluble epoxide hydrolase (sEH) related cardiovascular diseases (CVD) have revealed the physiological effects of EETs, mainly including vascular function regulation, angiogenesis, myocardial fibrosis, myocardial hypertrophy, and cardiovascular inflammation. At the same time, clinical studies have found that most of the substrates and inhibitors of CYP2J2 affect the content of EETs, resulting in cardiotoxicity of drugs. Therefore, the regulation of CYP and sEH enzymes on EETs points out the direction for exploring EET-mediated cardiac protection. The metabolic pathway of EETs is not only an important target for the development of new drugs for CVD but also an important factor in preventing drug cardiotoxicity. The development and clinical application of sEH inhibitors and EETs analogues provide broad prospects for the treatment of CVD.

Emerging role of carboxylesterases in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is increasingly recognized as a global public health problem. Carboxylesterases (CESs), as potential influencing factors of NAFLD, are very important to improve clinical outcomes. This review aims to deeply understand the role of CESs in the progression of NAFLD and proposes that CESs can be used as potential targets for NAFLD treatment. We first introduced CESs and analyzed the relationship between CESs and hepatic lipid metabolism and inflammation. Then, we further reviewed the regulation of nuclear receptors on CESs, including PXR, CAR, PPARα, HNF4α and FXR, which may influence the progression of NAFLD. Finally, we evaluated the advantages and disadvantages of existing NAFLD animal models and summarized the application of CES-related animal models in NAFLD research. In general, this review provides an overview of the relationship between CESs and NAFLD and discusses the role and potential value of CESs in the treatment and prevention of NAFLD.

Hypercholesterolemia reduces the expression and function of hepatic drug metabolizing enzymes and transporters in rats.

Hypercholesterolemia, one of the most common lipid metabolic diseases, may cause severe complications and even death. However, the effect of hypercholesterolemia on drug-metabolizing enzymes and transporters remains unclear. In this report, we established a rat model of diet-induced hypercholesterolemia. Quantitative real-time PCR and Western blot analysis were used to study the mRNA and protein expression of drug-metabolizing enzymes and transporters. The functions of these enzymes and transporters were evaluated by the cocktail assay. In hypercholesterolemic rats, the expression of phase I enzymes (CYP1A2, CYP2C11, CYP2E1, CYP3A1/2, CYP4A1 and FMO1/3) and phase II enzymes (UGT1A1/3, PROG, AZTG, SULT1A1, NAT1 and GSTT1) decreased. In addition, the mRNA levels of drug transporter Slco1a1/2, Slco1b2, Slc22a5, Abcc2, Abcb1a and Abcg2 decreased in rats with hypercholesterolemia, while Abcb1b and Abcc3 increased. The decreased expression of hepatic phase I and II enzymes and transporters may be caused by the changes of CAR, FXR, PXR, and Hnf4α levels. In conclusion, diet-induced hypercholesterolemia changes the expression and function of hepatic drug-metabolizing enzymes and transporters in rats, thereby possibly affecting drug metabolism and pharmacokinetics. In clinical hyperlipidemia, patients should strengthen drug monitoring to avoid possible drug exposure mediated risks.

Intranasal administration of white tea alleviates the olfactory function deficit induced by chronic unpredictable mild stress.

CONTEXT: White tea [Camellia sinensis (L) O.Ktze. (Theaceae)] is popular in Asia, but its benefits on olfactory injury are unknown. OBJECTIVE: The present study explores the effects of white tea on the olfactory injury caused by chronic unpredictable mild stress (CUMS). MATERIALS AND METHODS: C57BL/6J mice (WT) were exposed to CUMS. CUMS mice (CU) were intranasally treated with white tea extract [low tea (LT), 20 mg/kg; high tea (HT), 40 mg/kg] and fluoxetine (CF, 20 mg/kg) for 7 days. Several behavioural tests were conducted to assess depression and olfactory function. The transmission electron microscope (TEM) and semi-quantitative reverse transcription PCR were performed separately to observe the changes of related structures and genes transcription level. RESULTS: The depressive behaviours of the LT and HT mice were reversed. The latency time of the buried food pellet test decreased from 280 s (CU) to 130 s (HT), while the olfactory sensitivity and olfactory avoidance test showed that the olfactory behaviours disorder of LT and HT mice were alleviated. The white tea increased the A490 nm values of the cortisol treated cells from 0.15 to 1.4. Reduced mitochondrial and synaptic damage in the olfactory bulb (OB), enhanced expression of the brain-derived neurotrophic factor (BDNF) and olfactory marker protein (OMP) were observed in the LT and HT mice. CONCLUSIONS AND DISCUSSION: White tea has the potential in curing the olfactory deficiency related to chronic stress. It lays the foundation for the development of new and reliable drug to improve olfactory.

Proteasome activator PA28γ-dependent degradation of coronavirus disease (COVID-19) nucleocapsid protein.

The nucleocapsid protein is significant in the formation of viral RNA of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), accounting for the largest proportion of viral structural proteins. Here, we report for the first time that the 11S proteasomal activator PA28γ regulates the intracellular abundance of the SARS-CoV-2 N protein (nCoV N). Furthermore, we have identified proteasome activator PA28γ as a nCoV N binding protein by co-immunoprecipitation assay. As a result of their interaction, nCoV N could be degraded by PA28γ-20S in vitro degradation assay. This was also demonstrated by blocking de novo protein synthesis with cycloheximide. The stability of nCoV N in PA28γ-knockout cells was greater than in PA28γ-wildtype cells. Notably, immunofluorescence staining revealed that knockout of the PA28γ gene in cells led to the transport of nCoV N from the nucleus to the cytoplasm. Overexpression of PA28γ enhanced proteolysis of nCoV N compared to that in PA28γ-N151Y cells containing a dominant-negative PA28γ mutation, which reduced this process. These results suggest that PA28γ binding is important in regulating 20S proteasome activity, which in turn regulates levels of the critical nCoV N nucleocapsid protein of SARS-CoV-2, furthering our understanding of the pathogenesis of COVID-19.

Age-specific effects of P2X7 receptors on olfactory function in mice.

This study aimed to explore the age-specific effects of P2X7 receptor (P2X7R) knockout on olfactory function in mice. In this study, we analyzed olfactory functions of 2-month-old, 10-month-old and 18-month-old female P2X7R KO mice and age-matched female C57BL/6 wildtype mice (WT mice) by buried food seeking test and olfactory avoidance test. The structure of mitochondria and synapses in olfactory bulb were observed by electron microscopy. The content of interleukin-1 (IL-1ß) in olfactory bulb and transforming growth factor beta 1 (TGF-ß1) in olfactory epithelium were analyzed by ELISA. The results indicated that middle and old-aged P2X7R KO mice showed better olfactory function than middle and old-aged WT mice. Mitochondrial structures were complete and more spine synapses were observed in middle and old-aged P2X7R KO mice. Compared with middle and old-aged WT mice, IL-1ß content in olfactory bulb was decreased in middle and old-aged P2X7R KO mice, and there was no significant difference in TGF-ß1 content in olfactory epithelium. However, worse olfactory function was observed in young-aged P2X7R KO mice compared with young-aged WT mice. Abnormal mitochondrial structure and less synapses in olfactory bulb were observed. TGF-ß1 content in olfactory epithelium was significantly higher in P2X7R KO mice compared with young-aged WT mice. There was no significant difference in IL-1ß content in olfactory bulb of young-aged mice. In conclusion, P2X7R knockout can improve the olfactory function of middle and old-aged mice, while it may cause damage to young-aged mice, suggesting that P2X7R plays age-specific role on olfactory functions in mice.

Effect of Motion Perception on Intertemporal Choice Is Associated With the Altered Time Perception.

Intertemporal choice refers to the choice between receiving a small immediate reward or a large delayed one. Previous studies have indicated that time perception plays a critical role in the intertemporal choice, and it could be affected by the features of the target stimulus in the time reproduction task, such as speed of movement and state of motion. However, there is no evidence about whether backward or forward motion perception could alter the intertemporal choice. Thus, in our current study, 29 participants were asked to perform two tasks in a random order. One was the intertemporal choice task after viewing videos containing moving elements with forward/backward directions as well as stationary ones, and another was the time perception task. We found that the discounting rate in intertemporal choice was significantly larger in backward motion condition than in both forward motion and stationary conditions, indicating that backward motion perception made participants more myopic (specifically, more likely to choose the smaller immediate reward instead of the large delayed one) during their decision-makings. Meanwhile, participants overestimated the temporal duration in a time perception task in backward motion condition compared to the other two conditions. Furthermore, the Pearson's correlation analysis showed that the changes of the intertemporal choice induced by backward motion perception could be associated with the altered time perception. As far as we know, we provide the first evidence on influence of motion perception on the intertemporal choice as well as its possible cognitive correlates, which extend previous studies on cognitive basis of the intertemporal choices.

The effects of P2X7 receptor knockout on emotional conditions over the lifespan of mice.

Neuroinflammation is one of the key factors contributing to depression. Recent studies have identified P2X7 receptor (P2X7r) as a major inflammatory regulator. However, the effects of P2X7r knockout (KO) on emotional conditions over the lifespan of mice are unknown. In this study, the effects of P2X7r deletion on emotional conditions over the lifespan of mice were investigated in young-aged (2 month old), middle-aged (10 month old), and old-aged (18 month old) female P2X7r KO mice and age-matched female C57BL/6 mice. Behavioral tasks were conducted by open field test, forced swimming test and sucrose preference test. Mitochondrial structures and spine synapses in hippocampus were examined by electron microscopy. Enzyme-linked immunosorbent assay was used to analyze the expression of interleukin-1ß and tumor necrosis factor-α. Western blot analysis was used to assess the expression of nuclear factor-kappa B (NF-κB) pathway-related proteins. The results indicated that middle-aged P2X7r KO mice displayed better emotional conditions than middle-aged WT mice. However, worse emotional conditions were observed in young-aged P2X7r KO mice. Moreover, abnormal mitochondrial structures and less spine synapses were observed in young-aged P2X7r KO mice. Mitochondrial structures were recovered and more spine synapses occurred in middle-aged P2X7r KO mice. In addition, expressions of interleukin-1ß, tumor necrosis factor-α, p-IKKα, p-IKKß, p-IκBα, and p-NF-κBp65 were decreased in middle-aged P2X7r KO mice, but increased in young-aged P2X7r KO mice. In conclusion, P2X7r KO improves the emotional conditions at later stages of the lifespan of mice, but not in all ages, suggesting time-specific roles of immune response in nervous system through NF-κB signaling pathway. Video abstract: http://links.lww.com/WNR/A494.

Hypolipidemic effect of Fragarianilgerrensis Schlecht. medicine compound on hyperlipidemic rats.

BACKGROUND: Fragarianilgerrensis Schlecht. medicine compound (FN-MC) is a kind of Chinese herbs' compound consisted of Fragarianilgerrensis Schlecht. and Centella asiatica (L.) Urban. The study was to investigate the hypolipidemia effect of FN-MC in a hypolipidemic rat model. METHODS: Male SD rats were randomly divided into five groups: normal-fat diet (NFD) group, high-fat diet (HFD) group, FN-MC (2 g/Kg) group, FN-MC (4 g/Kg) group and simvastatin (PDC) group. After FN-MC treatment, body weight, food intake, serum and hepatic biochemistry parameters of rats were measured and the pathological changes of liver and its cells were observed by optical microscope and transmission electron microscopy. RESULTS: The results showed that FN-MC significantly decreased the levels of serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL-C), apolipoprotein B (ApoB) and hepatic malondialdehyde (MDA), while increased serum high-density lipoprotein (HDL-C), apolipoprotein A1 (ApoA1) and hepatic Superoxide Dismutase (SOD). FN-MC also improved the structure of liver and decreased the lipid drops in the cytoplasm significantly. In addition, FN-MC significantly decreased the weight gain and had no significant effects on food intake. CONCLUSIONS: The study suggested that FN-MC exhibited strong ability to improve the dyslipidemia and prevent hepatic fatty deposition in rats fed with high-fat diet. Meanwhile, FN-MC exerted anti-obesity and antioxidant properties. HIGHLIGHTS: Fragarianilgerrensis Schlecht. medicine compound possesses a hypolipidemic effect on hyperlipidemic rat model Fragarianilgerrensis Schlecht. medicine compound administration improves the antioxidant capacity of rats Fragarianilgerrensis Schlecht. medicine compound prevents hepatic fatty deposition.

Antidiabetic and Neuroprotective Effect of the N-Butanol Extract of Fragaria nilgerrensis Schlecht. in STZ-Induced Diabetic Mice.

Diabetes has been associated with neurodegenerative disorders that are accompanied by memory loss and cognitive impairments, but there is no effective treatment for it at present. Fragaria nilgerrensis Schlecht. (FNS), a well-known Chinese materia medica, has been traditionally used for the folkloric treatment of diabetes and other diseases. However, its effects are poorly documented. Here, we investigated the antidiabetic and neuroprotective effect of FNS in diabetic mice. Thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) evaluations of N-butanol extract of Fragaria nilgerrensis Schlecht. (N-FNS) showed the presence of flavonoid and its structure is similar to scutellarin. For the first time, we show the potential neuroprotective and antidiabetic effects of FNS. After 4 weeks of FNS intervention, a significant decrease in blood glucose, increase in body weight, and amelioration in glucose tolerance were observed in FNS treated diabetic mice. In the acute study, FNS enhanced motor activity in the open field task and significantly prevented spatial-learning deficits in Morris water maze tests. Besides, synapse ultrastructure of the hippocampus showed that the mitochondrial morphology was basically restored and all the synaptic structural parameters were gradually normalized after treatment with FNS. Importantly, we found that the activities of SOD and CAT in liver and hippocampus of diabetic mice significantly increased after FNS administration. In vitro, FNS and scutellarin showed high DPPH radical scavenging activity. The study suggests that FNS exerted significant antidiabetic and neuroprotective effects which may be attributed to its antioxidant property.

Folic acid exerts antidepressant effects by upregulating brain-derived neurotrophic factor and glutamate receptor 1 expression in brain.

Folic acid is a vitamin with a variety of pharmacological effects. The present study aims to explore the beneficial effects of folic acid on chronic unpredictable mild stress (CUMS)-induced depression-like behaviors and its possible mechanisms. The behavioral tests including open-field test, tail suspension test, and forced swimming test were used to evaluate the antidepressant effects of folic acid. Then the changes of brain 5-hydroxytryptamine (5-HT) concentration, brain-derived neurotrophic factor (BDNF), glutamate receptor 1 (GluR1) expression levels, and synaptic organization were assessed to explore the antidepressant mechanisms of folic acid. Our results showed that CUMS caused significant depression-like behaviors, neuropathological changes, and decreased brain 5-HT concentration, BDNF, and GluR1 expression in the hippocampus and association cortex. In conclusion, the results showed that folic acid significantly improved depression-like behaviors in CUMS-induced rats, and its antidepressant effects might be related to the increase of brain 5-HT concentration, BDNF and GluR1 expression, and repair of synaptic organization in the brain.

Presenilin 2 deficiency facilitates Aß-induced neuroinflammation and injury by upregulating P2X7 expression.

Accumulating evidence suggests that ß-amyloid (Aß)-induced neuroinflammation plays a prominent and early role in Alzheimer's disease (AD). In this study, we demonstrated that Presenilin 2 (PS2) deficiency facilitates Aß-induced neuroinflammation and injury by upregulating P2X7 expression both in vitro and in vivo. PS2 knockout mice demonstrated increased cognitive impairments and cerebral injury. PS2 deficiency increased the expression of P2X7 both in neurons and microglial cells. Furthermore, extracellular ATP also increased in both Aß-treated and untreated PS2 knockout microglial cells. Notably, Aß-induced classical proinflammatory cytokines such as IL-1ß, IL-1α and TNF-α were increased in PS2 knockout microglial cells, suggesting a potential role for PS2 in the regulation of neuroinflammation. The expression of P2X7 clearly increased in PS2 knockdown BV2 cells. Consistent with in vivo data, Aß-induced IL-1ß production was also clearly enhanced in PS2 knockdown BV2 cells. Additionally, expression of the transcription factor Sp1 was increased in PS2 knockdown cells. When we treated PS2 knockdown cells with the specific Sp1 inhibitor MIT, we observed that enhanced P2X7 expression was significantly rescued. Taken together, these data suggests that PS2 plays a protective role during Aß-induced neuroinflammation and injury through down-regulation of P2X7 expression.