Phosphatase Inhibitors Function as Novel,Broad Spectrum Botulinum Neurotoxin Antagonists in Mouse and Human Embryonic Stem Cell-Derived Motor Neuron-Based Assays

There is an urgent need to develop novel treatments to counter Botulinum neurotoxin (BoNT) poisoning. Currently, the majority of BoNT drug development efforts focus on directly inhibiting the proteolytic components of BoNT, i.e. light chains (LC). Although this is a rational approach, previous research has shown that LCs are extremely difficult drug targets and that inhibiting multi-serotype BoNTs with a single LC inhibitor may not be feasible. An alternative approach would target neuronal pathways involved in intoxication/recovery, rather than the LC itself. Phosphorylation-related mechanisms have been implicated in the intoxication pathway(s) of BoNTs. However, the effects of phosphatase inhibitors upon BoNT activity in the physiological target of BoNTs, i.e. motor neurons, have not been investigated. In this study, a small library of phosphatase inhibitors was screened for BoNT antagonism in the context of mouse embryonic stem cell-derived motor neurons (ES-MNs). Four inhibitors were found to function as BoNT/A antagonists. Subsequently, we confirmed that these inhibitors protect against BoNT/A in a dose-dependent manner in human ES-MNs. Additionally, these compounds provide protection when administered in post-intoxication scenario. Importantly, the inhibitors were also effective against BoNT serotypes B and E. To the best of our knowledge, this is the first study showing phosphatase inhibitors as broad-spectrum BoNT antagonists.     

TOMM40 poly-T variants and cerebrospinal fluid amyloid beta levels in the elderly

A variable poly-T polymorphism in the TOMM40 gene, which is in linkage disequilibrium with APOE, was recently implicated with increased risk and earlier onset age for late-onset Alzheimer’s disease in APOE ε3 carriers. To elucidate potential neurobiological mechanisms underlying this association, we compared the effect of TOMM40 poly-T variants to the effect of APOE, an established LOAD-risk modulator, on cerebrospinal fluid (CSF) amyloid beta (Aβ) and tau levels, in cognitively intact elderly subjects. APOE ε4 carriers showed significant reductions in Aβ 1-42 levels compared to non-ε4 carriers, but no differences were detected across TOMM40 variants. Neither Aβ 1-40 nor tau levels were affected by APOE or TOMM40.     

Pro- and anti-oxidant effects of polyunsaturated fatty acid supplementation in HepG2 cells

PUFA are bioactive nutrients thought to be effective in the prevention of many chronic diseases. PUFA susceptibility to free radical oxidation represents the other side of the coin, and the role of PUFA as pro- or anti-oxidants is still an unanswered question. In this study we supplemented HepG2 cells with different PUFA, and observed different effects on cytotoxicity, oxidation and modulation of antioxidant defenses. These were not simply related to the length of carbon chain, or to the number and position of double bonds. ARA supply evidenced the induction of oxidative damage, while DHA supplemented cells appeared richer in antioxidant defenses. To our knowledge, our study is the first evidencing the different pro- or anti-oxidant effect of different fatty acids when supplemented to cells. Overall, this points out the importance of not generalizing dietary recommendations considering PUFA as one category, but to extend them to the individual fatty acids.     

Low birth weight and allergy: possible pleiotropic effect of ACP1

The well-known relationship between low birth weight and allergies prompted us to investigate a possible pleiotropic effect of ACP1 on these conditions. ACP1 is a polymorphic enzyme that affects signal transduction of insulin and other growth factors, T-cell receptor signaling, and the regulation of flavoenzyme activity. Our aim was to compare the relationship between ACP1 and allergy with the relationship between ACP1 and birth weight. We studied 299 subjects from the Caucasian population of England, 124 subjects from the Caucasian population of central Italy, and 302 healthy puerperae and their newborn babies from the same Caucasian populations. ACP1 phenotype was determined by starch gel electrophoresis on RBC hemolysate and by DNA analysis. Subjects with high ACP1 activity (ACP1 C,B phenotype) show a lower level of IgE compared to subjects with low ACP1 activity (p = 0.01). The proportion of infants with a birth weight below the first quartile is lower among infants born to mothers with high ACP1 activity than among infants born to mothers with medium-low activity (p = 0.01). The data suggest a protective effect of high-activity ACP1 C,B phenotype from low birth weight and from allergic manifestations after birth.     

Fine Structure of Antennal Sensilla of Paysandisia archon and Electrophysiological Responses to Volatile Compounds Associated with Host Palms

Paysandisia archon (Lepidoptera: Castniidae) is a serious pest of palm trees. A comprehensive knowledge of the insect olfactory system is essential for the development of efficient semiochemical-based control methods. The olfactory sensilla are located particularly on the antennae, and these can detect plant volatiles that provide important cues for the insects in the search for their host plants. To date, the fine structure of P. archon antennal sensilla studies and their role in host-plant perception have not been investigated in great detail. Using light microscopy and scanning and transmission electron microscopy, the antennae of both sexes of P. archon are described here in detail, according to the different types, quantities and distributions of the sensilla. Six types of sensilla were identified. The most widespread are sensilla trichoidea, sensilla basiconica and sensilla auricilica, which are associated with olfactory function. These have cuticular shafts characterised by numerous pores, and they are innervated by two or three sensory neurons. Sensilla coeloconica, sensilla chaetica and sensilla ampullacea are associated with olfactory or olfactory-thermoreception, mechano-gustatory, and thermo-hygroreception functions, respectively. Moreover, the role of P. archon antennae in locating of the host palms was evaluated using electroantennograms, to monitor responses to ester and terpene compounds previously identified as volatiles of damaged/fermenting palm tissues. P. archon showed responses to all of the synthetic chemicals tested, with greater responses in the females, providing a significant sex*dose effect. Among the compounds tested, ethyl isobutyrate elicited the strongest antenna responses. The fine structure of the cuticular and cellular components of the P. archon antenna sensory equipment is described for the first time. The results of this study form an important starting point and complement physiological and behavioural studies, to provide valuable information of practical importance for the development of efficient semiochemical-based control methods.     

The Effect of Mifepristone (RU 486) on Plasma Cortisol in Alzheimer’s Disease

The glucocorticoid receptor (GR) antagonist mifepristone (RU-486) has been reported to increase early morning plasma ACTH/cortisol in diverse non-demented populations. This pilot study examined the cortisol response to RU 486 in patients with Alzheimer’s disease (AD), a condition associated with abnormalities in various aspects of the hypothalamic-pituitary-adrenal (HPA) axis. Nine AD subjects were randomized in a placebo-controlled parallel study: 4 in the placebo group and 5 in the RU 486 group. Subjects received oral doses of RU 486 (200 mg) or placebo daily for 6-weeks. Morning plasma cortisol was determined at baseline, at 12 h following the first study drug dose, and weekly thereafter. RU 486 resulted in a significant increase in cortisol levels [F(1,6)=65.32; P<0.001]. The magnitude of this increase grew over the course of the study [F(1,6)=63.17; P<0.001], was not related to cortisol suppression after dexamethasone and appeared greater than that reported in the literature in younger populations in response to the same drug regimen. However, further studies with age-matched controls should be done to determine possible AD related changes in this response.