Astrocyte-derived lactoferrin inhibits neuronal ferroptosis by reducing iron content and GPX4 degradation in APP/PS1 transgenic mice.

Increased astrocytic lactoferrin (Lf) expression was observed in the brains of elderly individuals and Alzheimer's disease (AD) patients. Our previous study revealed that astrocytic Lf overexpression improved cognitive capacity by facilitating Lf secretion to neurons to inhibit ß-amyloid protein (Aß) production in APP/PS1 mice. Here, we further discovered that astrocytic Lf overexpression inhibited neuronal loss by decreasing iron accumulation and increasing glutathione peroxidase 4 (GPX4) expression in neurons within APP/PS1 mice. Furthermore, human Lf (hLf) treatment inhibited ammonium ferric citrate (FAC)-induced ferroptosis by chelating intracellular iron. Additionally, machine learning analysis uncovered a correlation between Lf and GPX4. hLf treatment boosted low-density lipoprotein receptor-related protein 1 (LRP1) internalization and facilitated its interaction with heat shock cognate 70 (HSC70), thereby inhibiting HSC70 binds to GPX4, and eventually attenuating GPX4 degradation and FAC-induced ferroptosis. Overall, astrocytic Lf overexpression inhibited neuronal ferroptosis through two pathways: reducing intracellular iron accumulation and promoting GPX4 expression via inhibiting chaperone-mediated autophagy (CMA)-mediated GPX4 degradation. Hence, upregulating astrocytic Lf expression is a promising strategy for combating AD.

Astrocyte-derived lactoferrin reduces ß-amyloid burden by promoting the interaction between p38 kinase and PP2A phosphatase in male APP/PS1 transgenic mice.

BACKGROUND AND PURPOSE: Overexpression of astrocytic lactoferrin (Lf) was observed in the brain of Alzheimer's disease (AD) patients, whereas the role of astrocytic Lf in AD progression remains unexplored. In this study, we aimed to evaluate the effects of astrocytic Lf on AD progression. EXPERIMENTAL APPROACH: Male APP/PS1 mice with astrocytes overexpressing human Lf were developed to evaluate the effects of astrocytic Lf on AD progression. N2a-sw cells also were employed to further uncover the mechanism of astrocytic Lf on ß-amyloid (Aß) production. KEY RESULTS: Astrocytic Lf overexpression increased protein phosphatase 2A (PP2A) activity and reduced amyloid precursor protein (APP) phosphorylation, Aß burden and tau hyperphosphorylation in APP/PS1 mice. Mechanistically, astrocytic Lf overexpression promoted the uptake of astrocytic Lf into neurons in APP/PS1 mice, and conditional medium from astrocytes overexpressing Lf inhibited p-APP (Thr668) expression in N2a-sw cells. Furthermore, recombinant human Lf (hLf) significantly enhanced PP2A activity and inhibited p-APP expression, whereas inhibition of p38 or PP2A activities abrogated the hLf-induced p-APP down-regulation in N2a-sw cells. Additionally, hLf promoted the interaction of p38 and PP2A via p38 activation, thereby enhancing PP2A activity, and low-density lipoprotein receptor-related protein 1 (LRP1) knockdown significantly reversed the hLf-induced p38 activation and p-APP down-regulation. CONCLUSIONS AND IMPLICATIONS: Our data suggested that astrocytic Lf promoted neuronal p38 activation, via targeting to LRP1, subsequently promoting p38 binding to PP2A to enhance PP2A enzyme activity, which finally inhibited Aß production via APP dephosphorylation. In conclusion, promoting astrocytic Lf expression may be a potential strategy against AD. LINKED ARTICLES: This article is part of a themed issue From Alzheimer's Disease to Vascular Dementia: Different Roads Leading to Cognitive Decline. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.6/issuetoc.

Associations of maternal pre-pregnancy BMI and gestational weight gain with the risks of adverse pregnancy outcomes in Chinese women with gestational diabetes mellitus.

BACKGROUND: Give the high background risk of adverse pregnancy outcomes (APOs), it is important to understand the associations of maternal pre-pregnancy body mass index (ppBMI), gestational weight gain (GWG) with APOs in women with gestational diabetes mellitus (GDM). We addressed the independent and joint associations of maternal ppBMI and GWG with APOs in Chinese women with GDM. METHODS: 764 GDM women with singleton delivery were studied and they were stratified into three weight groups by ppBMI (underweight, normal weight and overweight/obesity) following classification standards for Chinese adults and three GWG groups (inadequate, adequate, excessive GWG) by the 2009 Institute of Medicine guidelines, respectively. Univariate and multivariate logistic regression analyses were performed to estimate the odds ratios of APOs. RESULTS: Maternal overweight/obesity was associated with increased odds of pregnancy-induced hypertension [PIH, adjusted odds ratio (aOR): 2.828, 95% confidence interval (CI) 1.382-5.787], cesarean delivery (CS) (aOR 2.466, 95%CI 1.694-3.590), preterm delivery (aOR 2.466, 95%CI 1.233-4.854), LGA (aOR 1.664, 95%CI 1.120-2.472), macrosomia (aOR 2.682, 95%CI 1.511-4.760) and any pregnancy complication (aOR 2.766, 95%CI 1.840-4.158) compared with healthy weight. Inadequate GWG was less likely to develop PIH (aOR 0.215, 95%CI 0.055-0.835), CS (aOR 0.612, 95%CI 0.421-0.889) and any pregnancy complication (aOR 0.628, 95%CI 0.435-0.907), but had higher risk of preterm birth (aOR 2.261, 95%CI 1.089-4.692), while excessive GWG was more vulnerable to LGA (aOR 1.929, 95%CI 1.272-2.923), macrosomia (aOR 2.753, 95%CI 1.519-4.989) and any pregnancy complication (aOR 1.548, 95%CI 1.006-2.382) as compared to adequate GWG. Furthermore, compared to normal weight mothers with adequate GWG, obese mothers with excessive GWG had the highest risk of any pregnancy complication (aOR 3.064, 95%CI 1.636-5.739). CONCLUSIONS: Maternal overweight/obesity and GWG were associated with APOs in the already high-risk settings of GDM. Obese mothers with excessive GWG may confer the greatest risk of adverse outcomes. It was very helpful to reduce the burden of APOs and benefit GDM women by promoting a healthy pre-pregnancy BMI and GWG.

Graphdiyne nanoplatforms for photothermal-ferroptosis combination therapy against glioblastoma.

Glioblastoma (GBM) is one of the most malignant tumors of the central nervous system and has a poor prognosis. GBM cells are highly sensitive to ferroptosis and heat, suggesting thermotherapy-ferroptosis as a new strategy for GBM treatment. With its biocompatibility and photothermal conversion efficiency, graphdiyne (GDY) has become a high-profile nanomaterial. Here, the ferroptosis inducer FIN56 was employed to construct GDY-FIN56-RAP (GFR) polymer self-assembled nanoplatforms against GBM. GDY could effectively load FIN56 and FIN56 released from GFR in a pH-dependent manner. The GFR nanoplatforms possessed the advantages of penetrating the BBB and acidic environment-induced in situ FIN56 release. Moreover, GFR nanoplatforms induced GBM cell ferroptosis by inhibiting GPX4 expression, and 808 nm irradiation reinforced GFR-mediated ferroptosis by elevating the temperature and promoting FIN56 release from GFR. In addition, the GFR nanoplatforms were inclined to locate in tumor tissue, inhibit GBM growth, and prolong lifespan by inducing GPX4-mediated ferroptosis in an orthotopic xenograft mouse model of GBM; meanwhile, 808 nm irradiation further improved these GFR-mediated effects. Hence, GFR may be a potential nanomedicine for cancer therapy, and GFR combined with photothermal therapy may be a promising strategy against GBM.

Contrasting actions of a convulsant barbiturate and its anticonvulsant enantiomer on the α1 ß3 γ2L GABAA receptor account for their in vivo effects.

KEY POINTS: Most barbiturates are anaesthetics but unexpectedly a few are convulsants whose mechanism of action is poorly understood. We synthesized and characterized a novel pair of chiral barbiturates that are capable of photolabelling their binding sites on GABAA receptors. In mice the S-enantiomer is a convulsant, but the R-enantiomer is an anticonvulsant. The convulsant S-enantiomer binds solely at an inhibitory site. It is both an open state inhibitor and a resting state inhibitor. Its action is pH independent, suggesting the pyrimidine ring plays little part in binding. The inhibitory site is not enantioselective because the R-enantiomer inhibits with equal affinity. In contrast, only the anticonvulsant R-enantiomer binds to the enhancing site on open channels, causing them to stay open longer. The enhancing site is enantioselective. The in vivo actions of the convulsant S-enantiomer are accounted for by its interactions with GABAA receptors. ABSTRACT: Most barbiturates are anaesthetics but a few unexpectedly are convulsants. We recently located the anaesthetic sites on GABAA receptors (GABAA Rs) by photolabelling with an anaesthetic barbiturate. To apply the same strategy to locate the convulsant sites requires the creation and mechanistic characterization of a suitable agent. We synthesized enantiomers of a novel, photoactivable barbiturate, 1-methyl-5-propyly-5-(m-trifluoromethyldiazirinyl) phenyl barbituric acid (mTFD-MPPB). In mice, S-mTFD-MPPB acted as a convulsant, whereas R-mTFD-MPPB acted as an anticonvulsant. Using patch clamp electrophysiology and fast solution exchange on recombinant human α1 ß3 γ2L GABAA Rs expressed in HEK cells, we found that S-mTFD-MPPB inhibited GABA-induced currents, whereas R-mTFD-MPPB enhanced them. S-mTFD-MPPB caused inhibition by binding to either of two inhibitory sites on open channels with bimolecular kinetics. It also inhibited closed, resting state receptors at similar concentrations, decreasing the channel opening rate and shifting the GABA concentration-response curve to the right. R-mTFD-MPPB, like most anaesthetics, enhanced receptor gating by rapidly binding to allosteric sites on open channels, initiating a rate-limiting conformation change to stabilized open channel states. These states had slower closing rates, thus shifting the GABA concentration-response curve to the left. Under conditions when most GABAA Rs were open, an inhibitory action of R-mTFD-MPPB was revealed that had a similar IC50 to that of S-mTFD-MPPB. Thus, the inhibitory sites are not enantioselective, and the convulsant action of S-mTFD-MPPB results from its negligible affinity for the enhancing, anaesthetic sites. Interactions with these two classes of barbiturate binding sites on GABAA Rs underlie the enantiomers' different pharmacological activities in mice.

Pharmacological studies of methoxycarbonyl etomidate's carboxylic acid metabolite.

BACKGROUND: Methoxycarbonyl etomidate (MOC-etomidate) is a rapidly metabolized and ultrashort-acting etomidate analog that does not produce prolonged adrenocortical suppression after bolus administration. Its metabolite (MOC-ECA) is a carboxylic acid whose pharmacology is undefined. We hypothesized that MOC-ECA possesses significantly lower pharmacological activity than MOC-etomidate, accounting for the latter's very brief duration of hypnotic action and inability to produce prolonged adrenocortical suppression after bolus administration. To test this hypothesis, we compared the potencies of MOC-ECA and MOC-etomidate in 3 biological assays. METHODS: The hypnotic potency of MOC-ECA was assessed in tadpoles using a loss-of-righting reflexes assay. The γ-aminobutyric acid type A (GABA(A)) receptor modulatory potencies of MOC-ECA and MOC-etomidate were compared by defining the concentrations of each required to directly activate α(1)(L264T)ß(2)γ(2L) GABA(A) receptors. The adrenocortical inhibitory potencies of MOC-ECA and MOC-etomidate were compared by defining the concentrations of each required to inhibit in vitro cortisol production by adrenocortical cells. RESULTS: MOC-ECA's 50% effective concentration for loss-of-righting reflexes in tadpoles was 2.8 ± 0.64 mM as compared with a previously reported value of 8 ± 2 µM for MOC-etomidate. The 50% effective concentrations for direct activation of GABA(A) receptors were 3.5 ± 0.63 mM for MOC-ECA versus 10 ± 2.5 µM for MOC-etomidate. The half-maximal inhibitory concentration for inhibiting in vitro cortisol production by adrenocortical cells was 30 ± 7 µM for MOC-ECA versus 0.10 ± 0.02 µM for MOC-etomidate. CONCLUSIONS: In all 3 biological assays, MOC-ECA's potency was approximately 300-fold lower than that of MOC-etomidate.

[Comparison of allogenic versus ostetic artificial bone in double door laminoplasty].

OBJECTIVE: To study the application of allogenic bone and Ostetic artificial bone in double door laminoplasty. METHODS: From June 2004 to June 2010, a total of 111 patients underwent double door laminoplasty. And allogenic (group A, n = 63) and Ostetic artificial (group B, n = 48) bones were used. They had spinal stenosis at least several levels or OPLL (Ossification of posterior longitudinal ligament). Their follow-up period was 12 months. Anteroposterior compression ratio was used to evaluate the neurological status. Range-of-movement (ROM) of cervical spine and bone fusion was determined by radiography and computed tomography (CT) during the follow-ups. RESULTS: Anteroposterior compression ratio: group A improved from 0.18 preoperation to 0.43 postoperation while group B increased from 0.20 preoperation to 0.44 postoperation; ROM: group A decreased postoperatively to (22.6 ± 3.3)° from (39.5 ± 6.1)° while group B decreased postoperatively to (22.9 ± 3.7)° from (39.3 ± 6.7)°. When Groups A and B were compared, bone fusion between allograft and spinous processes was completed in 73.1% vs 64.2%, partial fusion in 22.4% vs 18.7% and failed in 6.3% vs 17.1%. CONCLUSION: Uses allogenic and Ostetic artificial bones in double door laminoplasty may achieve an excellent decompression of spinal cord. But the application of allogenic bone yields a higher bone fusion rate after surgery.

[Study on the effect of electric field on the secondary structure of HRP by circular dichroism].

After the HRP was treated with different strength of electric field, the effect of electric field on the secondary structure of HRP was studied by circular dichroism. The results show that different electric field strength ranging from 1.0 to 6.0 kV x cm(-1) has a different effect on the relative contents of alpha-helix, beta-sheet, beta-turn and random coil of the HRP. As compared with the contrast, the relative contents of alpha-helix, beta-turn and random coil decreased by 0.3%-11.4%, 1.7%-15.3% and 0.9%-20.4% respectively, while beta-sheet content increased by 0.9%-82.7%. The electric treatment tends to transform the alpha-helix, beta-turn and random coil into beta-sheet for the HRP. The result of this study has important meaning to explain the biological effect of electric treatment seeds.

[Study on the effect of electric field on the secondary structure of lipase by circular dichroism].

After the lipase was treated with electric field for five minutes, the effect of electric field on the secondary structure of lipase was studied by circular dichroism (CD). The results showed that different electric field strength in the range from 0. 5 to 6. 0 kV x cm(-1) has a different effect on the relative contents of alpha-helix, beta-sheet, beta-turn and random coil of the lipase, and whose changes were non-monotonous with the raising of electric field. In general, the electric treatment tends to transform the alpha-helix and beta-sheet into beta-turn and random coil. The decrease in alpha-helix and beta-sheet ranged respectively from 4. 6% to 48. 0% and from 13. 2% to 35. 1%, and the increase in beta-turn and random coil ranged respectively from 2. 8% to 33. 3% and from 0. 9% to 48. 1%. The result of this study has important meaning to explain the biological effect of electric treatment seeds.