3-Aminobenzamide Prevents Concanavalin A-Induced Acute Hepatitis by an Anti-inflammatory and Anti-oxidative Mechanism.

BACKGROUND AND AIMS: Concanavalin A is known to activate T cells and to cause liver injury and hepatitis, mediated in part by secretion of TNFα from macrophages. Poly(ADP-ribose) polymerase-1 (PARP-1) inhibitors have been shown to prevent tissue damage in various animal models of inflammation. The objectives of this study were to evaluate the efficacy and mechanism of the PARP-1 inhibitor 3-aminobenzamide (3-AB) in preventing concanavalin A-induced liver damage. METHODS: We tested the in vivo effects of 3-AB on concanavalin A-treated mice, its effects on lipopolysaccharide (LPS)-stimulated macrophages in culture, and its ability to act as a scavenger in in vitro assays. RESULTS: 3-AB markedly reduced inflammation, oxidative stress, and liver tissue damage in concanavalin A-treated mice. In LPS-stimulated RAW264.7 macrophages, 3-AB inhibited NFκB transcriptional activity and subsequent expression of TNFα and iNOS and blocked NO production. In vitro, 3-AB acted as a hydrogen peroxide scavenger. The ROS scavenger N-acetylcysteine (NAC) and the ROS formation inhibitor diphenyleneiodonium (DPI) also inhibited TNFα expression in stimulated macrophages, but unlike 3-AB, NAC and DPI were unable to abolish NFκB activity. PARP-1 knockout failed to affect NFκB and TNFα suppression by 3-AB in stimulated macrophages. CONCLUSIONS: Our results suggest that 3-AB has a therapeutic effect on concanavalin A-induced liver injury by inhibiting expression of the key pro-inflammatory cytokine TNFα, via PARP-1-independent NFκB suppression and via an NFκB-independent anti-oxidative mechanism.

Neural Stem Cell Transplant-Induced Effect on Neurogenesis and Cognition in Alzheimer Tg2576 Mice Is Inhibited by Concomitant Treatment with Amyloid-Lowering or Cholinergic α7 Nicotinic Receptor Drugs.

Stimulating regeneration in the brain has the potential to rescue neuronal networks and counteract progressive pathological changes in Alzheimer's disease (AD). This study investigated whether drugs with different mechanisms of action could enhance neurogenesis and improve cognition in mice receiving human neural stem cell (hNSC) transplants. Six- to nine-month-old AD Tg2576 mice were treated for five weeks with the amyloid-modulatory and neurotrophic drug (+)-phenserine or with the partial α7 nicotinic receptor (nAChR) agonist JN403, combined with bilateral intrahippocampal hNSC transplantation. We observed improved spatial memory in hNSC-transplanted non-drug-treated Tg2576 mice but not in those receiving drugs, and this was accompanied by an increased number of Doublecortin- (DCX-) positive cells in the dentate gyrus, a surrogate marker for newly generated neurons. Treatment with (+)-phenserine did however improve graft survival in the hippocampus. An accumulation of α7 nAChR-expressing astrocytes was observed around the injection site, suggesting their involvement in repair and scarring processes. Interestingly, JN403 treatment decreased the number of α7 nAChR-expressing astrocytes, correlating with a reduction in the number of DCX-positive cells in the dentate gyrus. We conclude that transplanting hNSCs enhances endogenous neurogenesis and prevents further cognitive deterioration in Tg2576 mice, while simultaneous treatments with (+)-phenserine or JN403 result in countertherapeutic effects.

Is Male Involvement in ANC and PMTCT Associated with Increased Facility-Based Obstetric Delivery in Pregnant Women?

Ensuring that pregnant women are delivering in a health facility and are attended to by skilled birth attendants is critical to reducing maternal and infant morbidity and mortality. This study sought to determine the associations between male involvement in antenatal care (ANC) services and pregnant women delivering at health facilities and being attended to by skilled birth attendants as well as attending postnatal care. This was a retrospective cohort study using secondary analysis of program data. We reviewed health records of all pregnant women who attended antenatal services irrespective of HIV status between March and December 2012 in 10 health facilities in three provinces of Zambia. An extraction questionnaire was used to collect sociodemographic and clinical information from registers used in services for maternal neonatal child health as well as delivery. Using logistic regression, we calculated the odds ratios (OR) and 95% confidence intervals (CI) of the association between (1) male involvement and delivery at a health facility by a skilled birth attendant and (2) male involvement and women's attendance at postnatal services. We found that more women who had been accompanied by their male partner during ANC delivered at a health facility than those who had not been accompanied (88/220 = 40% vs. 543/1787 = 30.4%, respectively; OR 1.53, 95% CI: 1.15-2.04). Also, we noted that a greater proportion of the women who returned for postnatal visits had been accompanied by their partner at ANC visits, compared to those women who came to ANC without their partner (106/220 = 48.2% vs. 661/1787 = 37.0%, respectively; OR 1.58, 95% CI: 1.20-2.10). Male involvement seems to be a key factor in women's health-seeking behaviours and could have a positive impact on maternal and infant morbidity and mortality.

Novel multivalent design of a monoclonal antibody improves binding strength to soluble aggregates of amyloid beta.

BACKGROUND: Amyloid-ß (Aß) immunotherapy is a promising therapeutic strategy in the fight against Alzheimer's disease (AD). A number of monoclonal antibodies have entered clinical trials for AD. Some of them have failed due to the lack of efficacy or side-effects, two antibodies are currently in phase 3, and one has been approved by FDA. The soluble intermediate aggregated species of Aß, termed oligomers and protofibrils, are believed to be key pathogenic forms, responsible for synaptic and neuronal degeneration in AD. Therefore, antibodies that can strongly and selectively bind to these soluble intermediate aggregates are of great diagnostic and therapeutic interest. METHODS: We designed and recombinantly produced a hexavalent antibody based on mAb158, an Aß protofibril-selective antibody. The humanized version of mAb158, lecanemab (BAN2401), is currently in phase 3 clinical trials for the treatment of AD. The new designs involved recombinantly fusing single-chain fragment variables to the N-terminal ends of mAb158 antibody. Real-time interaction analysis with LigandTracer and surface plasmon resonance were used to evaluate the kinetic binding properties of the generated antibodies to Aß protofibrils. Different ELISA setups were applied to demonstrate the binding strength of the hexavalent antibody to Aß aggregates of different sizes. Finally, the ability of the antibodies to protect cells from Aß-induced effects was evaluated by MTT assay. RESULTS: Using real-time interaction analysis with LigandTracer, the hexavalent design promoted a 40-times enhanced binding with avidity to protofibrils, and most of the added binding strength was attributed to the reduced rate of dissociation. Furthermore, ELISA experiments demonstrated that the hexavalent design also had strong binding to small oligomers, while retaining weak and intermediate binding to monomers and insoluble fibrils. The hexavalent antibody also reduced cell death induced by a mixture of soluble Aß aggregates. CONCLUSION: We provide a new antibody design with increased valency to promote binding avidity to an enhanced range of sizes of Aß aggregates. This approach should be general and work for any aggregated protein or repetitive target.

Clonal analysis of Notch1-expressing cells reveals the existence of unipotent stem cells that retain long-term plasticity in the embryonic mammary gland.

Recent lineage tracing studies have revealed that mammary gland homeostasis relies on unipotent stem cells. However, whether and when lineage restriction occurs during embryonic mammary development, and which signals orchestrate cell fate specification, remain unknown. Using a combination of in vivo clonal analysis with whole mount immunofluorescence and mathematical modelling of clonal dynamics, we found that embryonic multipotent mammary cells become lineage-restricted surprisingly early in development, with evidence for unipotency as early as E12.5 and no statistically discernable bipotency after E15.5. To gain insights into the mechanisms governing the switch from multipotency to unipotency, we used gain-of-function Notch1 mice and demonstrated that Notch activation cell autonomously dictates luminal cell fate specification to both embryonic and basally committed mammary cells. These functional studies have important implications for understanding the signals underlying cell plasticity and serve to clarify how reactivation of embryonic programs in adult cells can lead to cancer.

Neurotrophic and neuroprotective actions of (-)- and (+)-phenserine, candidate drugs for Alzheimer's disease.

Neuronal dysfunction and demise together with a reduction in neurogenesis are cardinal features of Alzheimer's disease (AD) induced by a combination of oxidative stress, toxic amyloid-ß peptide (Aß) and a loss of trophic factor support. Amelioration of these was assessed with the Aß lowering AD experimental drugs (+)-phenserine and (-)-phenserine in neuronal cultures, and actions in mice were evaluated with (+)-phenserine. Both experimental drugs together with the metabolite N1-norphenserine induced neurotrophic actions in human SH-SY5Y cells that were mediated by the protein kinase C (PKC) and extracellular signal-regulated kinases (ERK) pathways, were evident in cells expressing amyloid precursor protein Swedish mutation (APP(SWE)), and retained in the presence of Aß and oxidative stress challenge. (+)-Phenserine, together with its (-) enantiomer as well as its N1- and N8-norphenserine and N1,N8-bisnorphenserine metabolites, likewise provided neuroprotective activity against oxidative stress and glutamate toxicity via the PKC and ERK pathways. These neurotrophic and neuroprotective actions were evident in primary cultures of subventricular zone (SVZ) neural progenitor cells, whose neurosphere size and survival were augmented by (+)-phenserine. Translation of these effects in vivo was assessed in wild type and AD APPswe transgenic (Tg2576) mice by doublecortin (DCX) immunohistochemical analysis of neurogenesis in the SVZ, which was significantly elevated by 16 day systemic (+)-phenserine treatment, in the presence of a (+)-phenserine-induced elevation in brain- derived neurotrophic factor (BDNF).

Age-dependent neuroplasticity mechanisms in Alzheimer Tg2576 mice following modulation of brain amyloid-ß levels.

The objective of this study was to investigate the effects of modulating brain amyloid-ß (Aß) levels at different stages of amyloid pathology on synaptic function, inflammatory cell changes and hippocampal neurogenesis, i.e. processes perturbed in Alzheimer's disease (AD). Young (4- to 6-month-old) and older (15- to 18-month-old) APP(SWE) transgenic (Tg2576) mice were treated with the AD candidate drug (+)-phenserine for 16 consecutive days. We found significant reductions in insoluble Aß1-42 levels in the cortices of both young and older transgenic mice, while significant reductions in soluble Aß1-42 levels and insoluble Aß1-40 levels were only found in animals aged 15-18 months. Autoradiography binding with the amyloid ligand Pittsburgh Compound B ((3)H-PIB) revealed a trend for reduced fibrillar Aß deposition in the brains of older phenserine-treated Tg2576 mice. Phenserine treatment increased cortical synaptophysin levels in younger mice, while decreased interleukin-1ß and increased monocyte chemoattractant protein-1 and tumor necrosis factor-alpha levels were detected in the cortices of older mice. The reduction in Aß1-42 levels was associated with an increased number of bromodeoxyuridine-positive proliferating cells in the hippocampi of both young and older Tg2576 mice. To determine whether the increased cell proliferation was accompanied by increased neuronal production, the endogenous early neuronal marker doublecortin (DCX) was examined in the dentate gyrus (DG) using immunohistochemical detection. Although no changes in the total number of DCX(+)-expressing neurons were detected in the DG in Tg2576 mice at either age following (+)-phenserine treatment, dendritic arborization was increased in differentiating neurons in young Tg2576 mice. Collectively, these findings indicate that reducing Aß1-42 levels in Tg2576 mice at an early pathological stage affects synaptic function by modulating the maturation and plasticity of newborn neurons in the brain. In contrast, lowering Aß levels in Tg2576 mice when Aß plaque pathology is prominent mainly alters the levels of proinflammatory cytokines and chemokines.

High temperature triggers latent variation among individuals: oviposition rate and probability for outbreaks.

BACKGROUND: It is anticipated that extreme population events, such as extinctions and outbreaks, will become more frequent as a consequence of climate change. To evaluate the increased probability of such events, it is crucial to understand the mechanisms involved. Variation between individuals in their response to climatic factors is an important consideration, especially if microevolution is expected to change the composition of populations. METHODOLOGY/PRINCIPAL FINDINGS: Here we present data of a willow leaf beetle species, showing high variation among individuals in oviposition rate at a high temperature (20 °C). It is particularly noteworthy that not all individuals responded to changes in temperature; individuals laying few eggs at 20 °C continued to do so when transferred to 12 °C, whereas individuals that laid many eggs at 20 °C reduced their oviposition and laid the same number of eggs as the others when transferred to 12 °C. When transferred back to 20 °C most individuals reverted to their original oviposition rate. Thus, high variation among individuals was only observed at the higher temperature. Using a simple population model and based on regional climate change scenarios we show that the probability of outbreaks increases if there is a realistic increase in the number of warm summers. The probability of outbreaks also increased with increasing heritability of the ability to respond to increased temperature. CONCLUSIONS/SIGNIFICANCE: If climate becomes warmer and there is latent variation among individuals in their temperature response, the probability for outbreaks may increase. However, the likelihood for microevolution to play a role may be low. This conclusion is based on the fact that it has been difficult to show that microevolution affect the probability for extinctions. Our results highlight the urge for cautiousness when predicting the future concerning probabilities for extreme population events.

Functional interactions of fibrillar and oligomeric amyloid-ß with alpha7 nicotinic receptors in Alzheimer's disease.

Amyloid-ß (Aß) peptides in the brain of patients with Alzheimer's disease (AD) assemble into various aggregation forms that differ in size, structure, and functional properties. Previous studies have shown that Aß binds to nicotinic acetylcholine receptors (nAChRs) and activates signaling cascades that result in the disruption of synaptic functions. These findings suggest a possible link between impaired cholinergic neurotransmitter function in AD and Aß pathogenesis. However, it is not yet known how the different Aß assemblies interact with specific nAChR subtypes. In the present study, we demonstrate that neurotoxicity in neuronal cells in culture induced by fibrillar Aß(1-40) is prevented through an α7 nAChR-dependent mechanism. The α7 nAChR agonists varenicline and JN403 increased binding of the amyloid ligand [³H]PIB to fibrillar Aß in AD frontal cortex autopsy tissue. This suggests that the presence of nAChR agonists may inhibit interaction of Aß with α7 nAChRs and prevent the formation of Aß/α7 nAChR complexes. This interaction was confirmed in binding assays with [¹²5I]Aß(1-40) and α7 nAChRs in autopsy brain tissue homogenates from the frontal cortex. The functional effects of Aß fibrils and oligomers on nAChRs were examined by measuring intracellular calcium ([Ca(2+)](i) levels. Oligomeric, but not fibrillar Aß(1-40), increased [Ca(2+)](i) in neuronal cells, and this effect was attenuated by varenicline. Our findings demonstrate that fibrillar Aß exerts neurotoxic effects mediated partly through a blockade of α7 nAChRs, whilst oligomeric Aß may act as a ligand activating α7 nAChRs, thereby stimulating downstream signaling pathways.

Polycystic ovary syndrome and metformin in pregnancy.

UNLABELLED: The diagnostic criteria of polycystic ovary syndrome incorporate hyperandrogenism, polycystic ovaries, anovulation and irregular menstrual bleeding and the syndrome is a recognized reason behind infertility. The biguanide metformin has encouraging effects on several metabolic aspects of the syndrome, including insulin sensitivity, plasma glucose concentration and lipid profile. Moreover, metformin improves the ovarian function in women diagnosed with polycystic ovary syndrome. Hence, metformin is considered an agent for ovulation induction among these patients. However, even higher ovulation frequencies have been observed when metformin has been adjuvant to clomifene therapy. Metformin-induced ovulation presumably brings about resumption of regular menstrual cycles and improved conception rates. Polycystic ovary syndrome patients are presumably more likely than healthy women to suffer from pregnancy-related problems like early pregnancy loss, gestational diabetes mellitus and hypertensive states in pregnancy. Recent data suggest sparing effects of continued metformin therapy throughout pregnancy on early pregnancy loss and gestational diabetes mellitus, but its impact on hypertensive complications to pregnancy appears less evident. Instead, metformin might even induce pre-eclampsia or exert no effect on blood pressure. CONCLUSION: So far, evidence for safety of continued therapy throughout gestation is insufficient, and existing papers are limited in design and might mask for fetal toxic outcomes due to metformin therapy. Prior to a recommendation of sustained metformin therapy throughout pregnancy, randomized placebo-controlled double-blinded clinical trials are awaited with interest, so that present assumptions on efficiency can be clarified, in order to assure efficient and safe management of pregnant polycystic ovary syndrome patients.