Neurological impairment caused by Schistosoma mansoni systemic infection exhibits early features of idiopathic neurodegenerative disease.

Schistosomiasis, a neglected tropical disease caused by trematodes of the Schistosoma genus, affects over 250 million people around the world. This disease has been associated with learning and memory deficits in children, whereas reduced attention levels, impaired work capacity, and cognitive deficits have been observed in adults. Strongly correlated with poverty and lack of basic sanitary conditions, this chronic endemic infection is common in Africa, South America, and parts of Asia and contributes to inhibition of social development and low quality of life in affected areas. Nonetheless, studies on the mechanisms involved in the neurological impairment caused by schistosomiasis are scarce. Here, we used a murine model of infection with Schistosoma mansoni in which parasites do not invade the central nervous system to evaluate the consequences of systemic infection on neurologic function. We observed that systemic infection with S. mansoni led to astrocyte and microglia activation, expression of oxidative stress-induced transcription factor Nrf2, oxidative damage, Tau phosphorylation, and amyloid-ß peptide accumulation in the prefrontal cortex of infected animals. We also found impairment in spatial learning and memory as evaluated by the Morris water maze task. Administration of anthelmintic (praziquantel) and antioxidant (N-acetylcysteine plus deferoxamine) treatments was effective in inhibiting most of these phenotypes, and the combination of both treatments had a synergistic effect to prevent such changes. These data demonstrate new perspectives toward the understanding of the pathology and possible therapeutic approaches to counteract long-term effects of systemic schistosomiasis on brain function.

Gabapentin Inhibits Multiple Steps in the Amyloid Beta Toxicity Cascade.

Oligomeric ß-amyloid peptide (Aß) is one of the main neurotoxic agents of Alzheimer's disease (AD). Oligomers associate to neuronal membranes, forming "pore-like" structures that cause intracellular calcium and neurotransmitter dyshomeostasis, leading to synaptic failure and death. Through molecular screening targeting the C terminal region of Aß, a region involved in the toxic properties of the peptide, we detected an FDA approved compound, gabapentin (GBP), with neuroprotective effects against Aß toxicity. At micromolar concentrations, GBP antagonized peptide aggregation over time and reduced the Aß absorbance plateau to 28% of control. In addition, GBP decreased Aß association to membranes by almost half, and the effects of Aß on intracellular calcium in hippocampal neurons were antagonized without causing effects on its own. Finally, we found that GBP was able to block the synaptotoxicity induced by Aß in hippocampal neurons, increasing post-synaptic currents from 1.7 ± 0.9 to 4.2 ± 0.7 fC and mean relative fluorescence intensity values of SV2, a synaptic protein, from 0.7 ± 0.09 to 1.00 ± 0.08. The results show that GBP can interfere with Aß-induced toxicity by blocking multiple steps, resulting in neuroprotection, which justifies advancing toward additional animal and human studies.

Investigation of polysaccharide extracts from Iranian and French strains of Agaricus subrufescens against enzymes involved in Alzheimer's disease / Investigación de extractos de polisacáridos de cepas iraníes y francesas de Agaricus subrufescens contra enzimas relevantes para la enfermedad de Alzheimer

In this work, the inhibitory activity of a wide range of polysaccharide extracts from two Iranian and French strains of Agaricus subrufescens were evaluated toward acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Among them, two extracts S9 and S'7 obtained from Iranian and French strains under different extraction conditions showed selective AChE inhibitory activity with IC50 values of 154.63 and 145.43 µg/mL, respectively. It should be noted that all extracts from both strains demonstrated no BChE inhibitory activity. S9 and S'7 were also tested for their effect on amyloid beta (Aß) aggregation, antioxidant activity, and neuroprotectivity. Their activity against Aß aggregation was comparable to that of donepezil as the reference drug but they induced moderate antioxidant activity by DPPH radical scavenging activity and negligible neuroprotectivity against Aß-induced damage.

En este trabajo, se evaluó la actividad inhibitoria de acetilcolinesterasa (AChE) y butirilcolinesterasa (BChE) para varios extractos de polisacáridos de dos cepas iraníes y francesas de Agaricus subrufescens. Los extractos más potentes mostraron valores de IC50 de 154,63 y 145 µg/ml para las cepas iraní (S9) y francesa (S'7), respectivamente, las cuales se obtuvieron de diferentes condiciones de extracción; sin embargo, todos los extractos no mostraron actividad inhibitoria de BChE. Además, S9 y S'7 se probaron para determinar su efecto sobre la agregación de beta-amiloide (Aß), así como su actividad antioxidante y neuroprotectora. Su actividad inhibitoria de la agregación de Aß fue comparable con donepezil, fármaco de referencia, pero indujeron una actividad antioxidante moderada, medida mediante la captación de radicales DPPH, y una neuroprotectora insignificante contra el daño inducido por Aß.