Mechanisms of Hydrogen Sulfide against the Progression of Severe Alzheimer’s Disease in Transgenic Mice at Different Ages

Abstract Backgroud: Alzheimer disease is an age-related severe neurodegenerative pathology. The level of the third endogenous gas, hydrogen sulfide (H2S), is decreased in the brain of Alzheimer’s disease (AD) patients compared with the brain of the age-matched normal individuals; also, plasma H2S levels are negatively correlated with the severity of AD. Recently, we have demonstrated that systemic H2S injections are neuroprotective in an early phase of preclinical AD. Objectives: This study focuses on the possible neuroprotection of a chronic treatment with an H2S donor and sulfurous water (rich of H2S) in a severe transgenic 3×Tg-AD mice model. Method: 3×Tg-AD mice at 2 different ages (6 and 12 months) were daily treated intraperitoneally with an H2S donor and sulfurous water (rich of H2S) for 3 months consecutively. We investigated the cognitive ability, brain morphological alterations, amyloid/tau cascade, excitotoxic, inflammatory and apoptotic responses. Results: Three months of treatments with H2S significantly protected against impairment in learning and memory in a severe 3×Tg-AD mice model, at both ages studied, and reduced the size of Amyloid β plaques with preservation of the morphological picture. This neuroprotection appeared mainly in the cortex and hippocampus, associated with reduction in activity of c-jun N-terminal kinases, extracellular signal-regulated kinases and p38, which have an established role not only in the phosphorylation of tau protein but also in the inflammatory and excitotoxic response. Conclusion: Our findings indicate that appropriate treatments with various sources of H2S, might represent an innovative approach to counteract early and severe AD progression in humans

Bioresorbable Nanostructured Chemical Sensor for Monitoring of pH Level In Vivo

Here, the authors report on the manufacturing and in vivo assessment of a bioresorbable nanostructured pH sensor. The sensor consists of a micrometer-thick porous silica membrane conformably coated layer-by-layer with a nanometer-thick multilayer stack of two polyelectrolytes labeled with a pH-insensitive fluorophore. The sensor fluorescence changes linearly with the pH value in the range 4 to 7.5 upon swelling/shrinking of the polymer multilayer and enables performing real-time measurements of the pH level with high stability, reproducibility, and accuracy, over 100 h of continuous operation. In vivo studies carried out implanting the sensor in the subcutis on the back of mice confirm real-time monitoring of the local pH level through skin. Full degradation of the pH sensor occurs in one week from implant in the animal model, and its biocompatibility after 2 months is confirmed by histological and fluorescence analyses. The proposed approach can be extended to the detection of other (bio)markers in vivo by engineering the functionality of one (at least) of the polyelectrolytes with suitable receptors, thus paving the way to implantable bioresorbable chemical sensors

Identification of a Thyroid Hormone Derivative as a Pleiotropic Agent for the Treatment of Alzheimer's Disease.

The identification of effective pharmacological tools for Alzheimer's disease (AD) represents one of the main challenges for therapeutic discovery. Due to the variety of pathological processes associated with AD, a promising route for pharmacological intervention involves the development of new chemical entities that can restore cellular homeostasis. To investigate this strategy, we designed and synthetized SG2, a compound related to the thyroid hormone thyroxine, that shares a pleiotropic activity with its endogenous parent compound, including autophagic flux promotion, neuroprotection, and metabolic reprogramming. We demonstrate herein that SG2 acts in a pleiotropic manner to induce recovery in a C. elegans model of AD based on the overexpression of Aβ42 and improves learning abilities in the 5XFAD mouse model of AD. Further, in vitro ADME-Tox profiling and toxicological studies in zebrafish confirmed the low toxicity of this compound, which represents a chemical starting point for AD drug development

NDP-\u3b1-MSH induces intense neurogenesis and cognitive recovery in Alzheimer transgenic mice through activation of melanocortin MC4 receptors

Melanocortins exert neuroprotection in a variety of experimental neurodegenerative disorders, including Alzheimer's disease (AD). Further, in previous research we showed that these endogenous peptides stimulate neurogenesis in an acute neurodegenerative disorder such as ischemic stroke. In the present research, we investigated the potential neurogenic effect of melanocortins in AD using APPSwe transgenic mice (Tg2576). To this purpose, 24week-old animals were prepared for 5-bromo-2'-deoxyuridine (BrdU) labeling of proliferating cells on days 1-11 of the study. Treatment of Tg2576 mice with nanomolar doses of the melanocortin analog [Nle(4),D-Phe(7)]\u3b1-melanocyte-stimulating hormone (NDP-\u3b1-MSH), administered once daily from day 1 to 50, improved brain histology and cognitive functions relative to saline-treated Tg2576 animals. No signs of toxicity were observed. Immunohistochemical examination of the hippocampus at the end of the study (day 50) showed that NDP-\u3b1-MSH-treated Tg2576 mice had a greater number of BrdU immunoreactive cells colocalized with NeuN (an indicator of mature neurons) and Zif268 (an indicator of functionally integrated neurons) in the dentate gyrus, relative to saline-treated Tg2576 animals; no newly formed astrocytes were found. Animal pretreatment with selective melanocortin MC4 receptor antagonist HS024 before each NDP-\u3b1-MSH administration prevented all the beneficial effects of the peptide. The present data indicate that MC4 receptor stimulation by a melanocortin prevents cognitive decline in experimental AD, this effect being associated not only with neuroprotection but also with an intense neurogenesis. MC4 receptor agonists could be innovative and safe candidates to counteract AD progression in humans

Melanocortins promote neurogenesis and counteract cognitive decline in a transgenic mouse model of moderate Alzheimer\u2019s disease

Alzheimer's disease (AD), both sporadic and genetic, is a chronic disorder characterized by activation of the amyloid/tau cascade in the hippocampus and isocortex. Besides neuroprotective approaches, also neurorestorative strategies for AD are under intensive investigations. [1] The melanocortin system consists of endogenous neuropeptides of the adrenocorticotropin/melanocyte-stimulating hormone (ACTH/MSH) family, acting via five different metabotropic melanocortin receptor subtypes (MC1-MC5). Melanocortins also induce neuroprotection associated with long-lasting functional recovery and counteraction of cognitive decline, as found in acute experimental neurodegenerative conditions and more recently in a chronic neurodegenerative disease as AD. [2] Further, these endogenous peptides have been by us reported to stimulate neurogenesis in an acute neurodegenerative disorder as ischemic stroke. [3] Here we investigated the possible neuroprotective and neurogenic effect of melanocortins in AD with a medium level of severity by using 24 week-old (at the start of the study) APPSwe transgenic mice (Tg2576). METHODS: Tg2576 mice were treated (once daily on days 1-50) with a nanomolar dose of the melanocortin analog [Nle4,D-Phe7]\u3b1-melanocyte-stimulating hormone (NDP-\u3b1-MSH). Animals were prepared for 5-bromo-2\u2019-deoxyuridine (BrdU) labeling of proliferating cells at days 1-11 of the study, and histological and immunohistochemical studies of the brain were performed for the assessment of neurogenesis. Further, the mouse ability to learn and recall was evaluated by means of the Morris water-maze test at the twenty-seventh week (starting 14 days after the first BrdU injection) and thirty-first week of age. Within 90 min the end of the last behavioural test (day 50 of the study; 31 week-old mice) animals were killed and the brains were removed and processed for histological examination. The whole hippocampi were dissected from brains of some animals to perform western blot analysis of the Zif268 protein (Zif268 protein is transiently expressed after synaptic activation). All values were analyzed by means of two-way repeated measures ANOVA (behavioral data) or one-way ANOVA (all other data), both followed by the Student-Newman-Keuls\u2019 test. A value of p < 0.05 was considered significant. RESULTS: Treatment of Tg2576 mice with the melanocortin analog [Nle4,D-Phe7]\u3b1-melanocyte-stimulating hormone (NDP-\u3b1-MSH) reduced cerebral cortex/hippocampus level of A\u3b2 deposit (p < 0.001), increased hippocampus Zif268 expression (p <0.001), improved brain histological picture and cognitive functions (p <0.001), relative to saline-treated Tg2576 animals, and no signs of toxicity were recorded. Further, immunohistochemical examination of the hippocampus on day 50 (end of the study) showed, in the dentate gyrus of NDP-\u3b1-MSH-treated Tg2576 mice, a very elevated number of BrdU immunoreactive cells colocalized with NeuN (indicator of mature neurons) and Zif268 (indicator of functionally integrated neurons), in comparison with saline-treated Tg2576 animals (p <0.001); no newly formed astrocytes were found. Animal pretreatment (before each administration of NDP-\u3b1-MSH) with the selective melanocortin MC4 receptor antagonist HS024 prevented all favourable effects of NDP-\u3b1-MSH (p <0.001). CONCLUSIONS: Our data suggest that MC4 receptor-stimulating melanocortins are able to counteract cognitive decline in experimental AD not only by affording neuroprotection, but also by inducing intense neurogenesis. These agents could be candidates for an innovative and safe strategy to counteract AD progression in humans

NDP-α-MSH attenuates heart and liver responses to myocardial reperfusion via the vagus nerve and JAK/ERK/STAT signaling

Melanocortin peptides afford cardioprotection during myocardial ischemia/reperfusion via janus kinases (JAK), extracellular signal-regulated kinases (ERK) and signal transducers/activators of transcription (STAT) pathways. Here we investigated whether melanocortin-induced modulation of the JAK/ERK/STAT signaling occurs via the cholinergic anti-inflammatory pathway, focusing our study on cardiac and hepatic responses to prolonged myocardial ischemia/reperfusion. Ischemia was produced in rats by ligature of the left anterior descending coronary artery for 30min; effects of ischemia/reperfusion were evaluated using Western blot of heart and liver proteins. Intravenous treatment, during coronary artery occlusion, with the melanocortin analog (Nle(4), D-Phe(7))α-melanocyte-stimulating hormone (NDP-α-MSH) induced a left ventricle up-regulation of the cardioprotective transcription factors pJAK2, pERK1/2 and pTyr-STAT3 (JAK-dependent), and a reduction in the levels of the inflammatory mediators tumor necrosis factor-α (TNF-α) and pJNK (a transcription factor also involved in apoptosis), as assessed at the end of the 2-h reperfusion period. Further, these beneficial effects of NDP-α-MSH were associated with heart over-expression of the pro-survival proteins heme oxygenase-1 (HO-1) and Bcl-XL, and decrease of ventricular arrhythmias and infarct size. In the liver NDP-α-MSH induced a decrease in the pJAK2 and pTyr-STAT3 levels, and strongly reduced pERK1/2 expression. In the liver of ischemic rats NDP-α-MSH also blunted pJNK activity and TNF-α expression, and up-regulated Bcl-XL. Bilateral cervical vagotomy prevented all effects of NDP-α-MSH, both in the heart and liver. These results indicate that melanocortins inhibit heart and liver damage triggered by prolonged myocardial ischemia/reperfusion likely, as main mechanism, via the vagus nerve-mediated modulation of the JAK/STAT/ERK signaling pathways

Effects of COX1-2/5-LOX blockade in Alzheimer transgenic 3xTg-AD mice

Objective and design: Alzheimer’s disease (AD) is associated with amyloid plaques (Aβ) and hyperphosphorylated tau protein tangles in the brain. We investigated the possible neuroprotective role of flavocoxid, a dual inhibitor of cyclooxygenases-1/2 (COX-1/2) and 5-Lipoxygenase (5-LOX), in triple-transgenic (3xTg-AD) mice. Subjects: Mice were 3 months at the beginning of the study. Treatment: Animals received once daily for 3-month saline solution or flavocoxid (20&nbsp;mg/kg/ip). Methods: Morris water maze was used to assess learning and memory. Histology was performed to evidence Aβ plaques and neuronal loss, while inflammatory proteins were determined by western blot analysis. Results: Saline-treated 3xTg-AD mice showed an impairment in spatial learning and memory (assessed at 6 months of age), and increased expression of inflammatory and apoptotic molecules. Treatment of 3xTg-AD mice with flavocoxid reduced: (1) learning and memory loss; (2) the increased eicosanoid production and the phosphorylation level of amyloid precursor protein (APP-pThr668), Aβ 1–42, p-tau (pThr181), pERK, and the activation of the NLRP3 inflammasome; (3) Aβ plaques; and (4) neuronal loss, compared to saline-treated animals. Conclusions: Pharmacological blockade of both COX-1/2 and 5-LOX was able to counteract the progression of AD by targeting pathophysiological mechanisms up- and downstream of Aβ and tau

Un modello di analisi delle domande aperte nell\u2019indagine nazionale SIRD sulla didattica a distanza durante l\u2019emergenza Covid-19

La Societ\ue0 Italiana di Ricerca Didattica (SIRD) ha promosso una ricerca nazionale per avviare una riflessione sulla didattica a distanza (DaD) adottata durante l\u2019emergenza Covid-19. La ricerca \ue8 stata condotta mediante l\u2019utilizzo di un questionario a cui hanno risposto oltre 16.000 insegnanti di ogni ordine e grado, dislocati in tutto il territorio nazionale. Il contributo descrive la metodologia utilizzata per l\u2019analisi dei dati qualitativi e presenta la struttura categoriale emersa. Le domande aperte erano volte a far emergere i punti di forza e di debolezza della DaD, nonch\ue9 le difficolt\ue0 riscontrate dagli studenti. Uno spazio dedicato a commenti e riflessioni, inoltre, ha consentito di cogliere in modo maggiormente circostanziato il punto di vista degli insegnanti interpellati.The Italian Society for Educational Research (SIRD) promoted a national research initiative in order to reflect on the remote education methods adopted during the Covid-19 emergency. The research was conducted by means of a questionnaire answered by more than 16,000 teachers from schools of all types and at all levels throughout the country. This paper describes the methodology used for the qualitative analysis and illustrates the structure of the categories. The open questions investigated the strengths and weaknesses of remote education and the difficulties encountered by students. Furthermore, a space for comments and reflections made it possible to investigate in depth the teacher\u2019s point of view

Melanocortin receptor 4 as a new target in melanoma therapy: Anticancer activity of the inhibitor ML00253764 alone and in association with B-raf inhibitor vemurafenib

: The aim of our study is to investigate in vitro and in vivo MC4R as a novel target in melanoma using the selective antagonist ML00253764 (ML) alone and in combination with vemurafenib, a B-rafV600E inhibitor. The human melanoma B-raf mutated A-2058 and WM 266-4 cell lines were used. An MC4R null A-2058 cell line was generated using a CRISPR/Cas9 system. MC4R protein expression was analysed by western blotting, immunohistochemistry, and immunofluorescence. Proliferation and apoptotic assays were performed with ML00253764, whereas the synergism with vemurafenib was evaluated by the combination index (CI) and Loewe methods. ERK1/2 phosphorylation and BCL-XL expression were quantified by western blot. In vivo experiments were performed in Athymic Nude-Foxn1nu male mice, injecting subcutaneously melanoma cells, and treating animals with ML, vemurafenib and their concomitant combination. Comet and cytome assays were performed. Our results show that human melanoma cell lines A-2058 and WM 266-4, and melanoma human tissue, express functional MC4R receptors on their surface. MC4R receptors on melanoma cells can be inhibited by the selective antagonist ML, causing antiproliferative and proapoptotic activity through the inhibition of phosphorylation of ERK1/2 and a reduction of BCL-XL. The concomitant combination of vemurafenib and ML caused a synergistic effect on melanoma cells in vitro and inhibited in vivo tumor growth in a preclinical model, without causing mouse weight loss or genotoxicity. Our original research contributes to the landscape of pharmacological treatments for melanoma, providing MC4R antagonists as drugs that can be added to established therapies