The New Pharmacological Chaperones PBXs Increase α-Galactosidase A Activity in Fabry Disease Cellular Models

Fabry disease is an X-linked multisystemic disorder caused by the impairment of lysosomal α-Galactosidase A, which leads to the progressive accumulation of glycosphingolipids and to defective lysosomal metabolism. Currently, Fabry disease is treated by enzyme replacement therapy or the orally administrated pharmacological chaperone Migalastat. Both therapeutic strategies present limitations, since enzyme replacement therapy has shown low half-life and bioavailability, while Migalastat is only approved for patients with specific mutations. The aim of this work was to assess the efficacy of PBX galactose analogues to stabilize α-Galactosidase A and therefore evaluate their potential use in Fabry patients with mutations that are not amenable to the treatment with Migalastat. We demonstrated that PBX compounds are safe and effective concerning stabilization of α-Galactosidase A in relevant cellular models of the disease, as assessed by enzymatic activity measurements, molecular modelling, and cell viability assays. This experimental evidence suggests that PBX compounds are promising candidates for the treatment of Fabry disease caused by mutations which affect the folding of α-Galactosidase A, even for GLA variants that are not amenable to the treatment with Migalastat.

Chronic traumatic encephalopathy: an update review

Chronic traumatic encephalopathy is a progressive neurodegenerative disease occurring in retired sportspersons who have received several head blows with concussions during their games. The clinical symptoms start with mood disorders and with a progressive evolution into dementia and Parkinsonism. The disease is due to a progressive accumulation of hyperphosphorilated tau in neurons as neurofibrillary tangles, abnormal neurites and inclusions in astrocytes around small vessels. There is a tendency of the lesions to occur in clusters at the sulcal depths of the cerebral cortex. Chronic traumatic encephalopathy has to be differentiated from Alzheimer’s disease, in which head trauma can also increase the illness symptoms. Recently, new tracers in positron emission topography of the brain have been used for a better evaluation of chronic traumatic encephalopathy. There is actually no treatment that allows to cure or to slowdown the evolution of chronic traumatic encephalopathy. However, new treatment studies are recently conducted and in progress.

Autophagy and Aging: Roles in Skeletal Muscle, Eye, Brain and Hepatic Tissue

Autophagy is an evolutionary conserved degradative process contributing to cytoplasm quality control, metabolic recycling and cell defense. Aging is a universal phenomenon characterized by the progressive accumulation of impaired molecular and reduced turnover of cellular components. Recent evidence suggests a unique role for autophagy in aging and age-related disease. Indeed, autophagic activity declines with age and enhanced autophagy may prevent the progression of many age-related diseases and prolong life span. All tissues experience changes during aging, while the role of autophagy in different tissues varies. This review summarizes the links between autophagy and aging in the whole organism and discusses the physiological and pathological roles of autophagy in the aging process in tissues such as skeletal muscle, eye, brain, and liver.

Chronic Exposure to Paraquat Induces Alpha-Synuclein Pathogenic Modifications in Drosophila

Parkinson’s disease (PD) is characterized by the progressive accumulation of neuronal intracellular aggregates largely composed of alpha-Synuclein (aSyn) protein. The process of aSyn aggregation is induced during aging and enhanced by environmental stresses, such as the exposure to pesticides. Paraquat (PQ) is an herbicide which has been widely used in agriculture and associated with PD. PQ is known to cause an increased oxidative stress in exposed individuals but the consequences of such stress on aSyn conformation remains poorly understood. To study aSyn pathogenic modifications in response to PQ, we exposed Drosophila expressing human aSyn to a chronic PQ protocol. We first showed that PQ exposure and aSyn expression synergistically induced fly mortality. The exposure to PQ was also associated with increased levels of total and phosphorylated forms of aSyn in the Drosophila brain. Interestingly, PQ increased the detection of soluble aSyn in highly denaturating buffer but did not increase aSyn resistance to proteinase K digestion. These results suggest that PQ induces the accumulation of toxic soluble and misfolded forms of aSyn but that these toxic forms do not form fibrils or aggregates that are detected by the proteinase K assay. Collectively, our results demonstrate that Drosophila can be used to study the effect of PQ or other environmental neurotoxins on aSyn driven pathology.

Lifespan of Catalase-Deficient Mice Decreases Due to Lysosomal Dysfunction

Background: Lysosomes are a central hub for cellular metabolism and are involved in the regulation of cell homeostasis through the degradation or recycling of unwanted or dysfunctional organelles through the autophagy pathway. Catalase, a peroxisomal enzyme, plays an important role in cellular antioxidant defense by decomposing hydrogen peroxide into water and oxygen. In accordance with pleiotropic significance, both impaired lysosomes and catalase have been linked to many age-related pathologies with a decline in lifespan. Aging is characterized by progressive accumulation of macromolecular damage and the production of high levels of reactive oxygen species (ROS). Although lysosomes degrade the most long-lived proteins and organelles via the autophagic pathway, the role of lysosomes and their effect on peroxisomes during aging is not known. The present study investigated the role of catalase and lysosomal function in catalase-knockout (KO) mice.Results: We found that catalase-deficient mice exhibited an aging phenotype faster than wild-type (WT) mice. We also found that aged catalase-KO mice induced leaky lysosomes by progressive accumulation of lysosomal contents, such as cathespin D, into the cytosol. Leaky lysosomes inhibited autophagosome formation and triggered impaired autophagy. The dysregulation of autophagy triggered mTORC1 (mechanistic target of rapamycin complex 1) activation, which plays a pivotal role in modulating aging. However, the antioxidant N-acetyl-L-cysteine (NAC) and mTORC1 inhibitor rapamycin rescued leaky lysosomes and aging phenotypes in catalase-deficient aged mice.Conclusion: This study unveils the new role of catalase and its role in lysosomal function during aging.

TREM2 modulates differential deposition of modified and non-modified Aβ species in extracellular plaques and intraneuronal deposits

Progressive accumulation of Amyloid-β (Aβ) deposits in the brain is a characteristic neuropathological hallmark of Alzheimer’s disease (AD). During disease progression, extracellular Aβ plaques undergo specific changes in their composition by the sequential deposition of different modified Aβ species. Microglia are implicated in the restriction of amyloid deposits and play a major role in internalization and degradation of Aβ. Recent studies showed that rare variants of the Triggering Receptor Expressed on Myeloid cells 2 (TREM2) are associated with an increased risk for AD. Post-translational modifications of Aβ could modulate the interaction with TREM2, and the uptake by microglia. Here, we demonstrate that genetic deletion of TREM2 or expression of a disease associated TREM2 variant in mice lead to differential accumulation of modified and non-modified Aβ species in extracellular plaques and intraneuronal deposits. Human brains with rare TREM2 AD risk variants also showed altered deposition of modified Aβ species in the different brain lesions as compared to cases with the common variant of TREM2. These findings indicate that TREM2 plays a critical role in the development and the composition of Aβ deposits, not only in extracellular plaques, but also intraneuronally, that both could contribute to the pathogenesis of AD.

EP.FRI.999 Case report of a Low Grade appendiceal mucinous neoplasm (LAMN) and review of literature

A mucocele refers to an appendix that has dilated due to progressive accumulation of mucus within its lumen. Appendiceal mucocele is a rare cause of an acute abdomen. They represent 0.2-0.7% of all appendix specimens. LAMN account for less than 0.3% of appendicectomy specimens. We present a 38 year old man with an acute RIF’s pain who went on to have CT scan which revealed a mucocele of appendix but did not show any features of perforation or pseudomyxoma peritonei. He had a laparoscopic converted to open appendicectomy. The proximal 2 cm of appendix was oedematous but normal calibre. Histology revealed a low grade appendiceal mucinous neoplasm (LAMN) that was completely excised. The mucocele of the appendix was first described by Rokitansky in 1842. Appendix mucocele may come as a consequence of obstructive or inflammatory processes, cystadenomas or cystadenocarcinomas. Appendiceal mucinous neoplasms commonly presents in the sixth decade of life and our patient was much younger in comparison. Several literatures suggest the value of preoperative CT imaging in obtaining diagnosis and also in planning further treatment. Appendicectomy or a right hemicolectomy is treatment of choice based on presence or absence of following factors 1. Perforated mucocele 2. Involvement of the base of the appendix. 3. Positive lymph nodes of mesoappendix and ileocolic. Patients with malignancy or pseudomyxoma peritonei are likely to require cytoreductive surgery, heated intraoperative intraperitoneal chemotherapy, early postoperative intraperitoneal chemotherapy.

Selective Autophagy as a Potential Therapeutic Target in Age-Associated Pathologies

Progressive accumulation of damaged cellular constituents contributes to age-related diseases. Autophagy is the main catabolic process, which recycles cellular material in a multitude of tissues and organs. Autophagy is activated upon nutrient deprivation, and oncogenic, heat or oxidative stress-induced stimuli to selectively degrade cell constituents and compartments. Specificity and accuracy of the autophagic process is maintained via the precision of interaction of autophagy receptors or adaptors and substrates by the intricate, stepwise orchestration of specialized integrating stimuli. Polymorphisms in genes regulating selective autophagy have been linked to aging and age-associated disorders. The involvement of autophagy perturbations in aging and disease indicates that pharmacological agents balancing autophagic flux may be beneficial, in these contexts. Here, we introduce the modes and mechanisms of selective autophagy, and survey recent experimental evidence of dysfunctional autophagy triggering severe pathology. We further highlight identified pharmacological targets that hold potential for developing therapeutic interventions to alleviate cellular autophagic cargo burden and associated pathologies.

The Evolution of the Hallmarks of Aging

The evolutionary theory of aging has set the foundations for a comprehensive understanding of aging. The biology of aging has listed and described the “hallmarks of aging,” i.e., cellular and molecular mechanisms involved in human aging. The present paper is the first to infer the order of appearance of the hallmarks of bilaterian and thereby human aging throughout evolution from their presence in progressively narrower clades. Its first result is that all organisms, even non-senescent, have to deal with at least one mechanism of aging – the progressive accumulation of misfolded or unstable proteins. Due to their cumulation, these mechanisms are called “layers of aging.” A difference should be made between the first four layers of unicellular aging, present in some unicellular organisms and in all multicellular opisthokonts, that stem and strike “from the inside” of individual cells and span from increasingly abnormal protein folding to deregulated nutrient sensing, and the last four layers of metacellular aging, progressively appearing in metazoans, that strike the cells of a multicellular organism “from the outside,” i.e., because of other cells, and span from transcriptional alterations to the disruption of intercellular communication. The evolution of metazoans and eumetazoans probably solved the problem of aging along with the problem of unicellular aging. However, metacellular aging originates in the mechanisms by which the effects of unicellular aging are kept under control – e.g., the exhaustion of stem cells that contribute to replace damaged somatic cells. In bilaterians, additional functions have taken a toll on generally useless potentially limited lifespan to increase the fitness of organisms at the price of a progressively less efficient containment of the damage of unicellular aging. In the end, this picture suggests that geroscience should be more efficient in targeting conditions of metacellular aging rather than unicellular aging itself.

Human α-synuclein overexpression in mouse serotonin neurons triggers a depressive-like phenotype. Rescue by oligonucleotide therapy

Anxiety and depression affect 35–50% of patients with Parkinson's disease (PD), often precede the onset of motor symptoms, and have a negative impact on their quality of life. Dysfunction of the serotonergic (5-HT) system, which regulates mood and emotional pathways, occurs during the premotor phase of PD and contributes to a variety of non-motor symptoms. Furthermore, α-synuclein (α-Syn) aggregates were identified in raphe nuclei in the early stages of the disease. However, there are very few animal models of PD-related neuropsychiatric disorders. Here, we develop a new mouse model of α-synucleinopathy in the 5-HT system that mimics prominent histopathological and neuropsychiatric features of human PD. We showed that adeno-associated virus (AAV5)-induced overexpression of wild-type human α-Syn (h-α-Syn) in raphe 5-HT neurons triggers progressive accumulation, phosphorylation, and aggregation of h-α-Syn protein in the 5-HT system. Specifically, AAV5-injected mice displayed axonal impairment in the output brain regions of raphe neurons, and deficits in brain-derived neurotrophic factor (BDNF) expression and 5-HT neurotransmission, resulting in a depressive-like phenotype. Intracerebroventricular treatment with an indatraline-conjugated antisense oligonucleotide (IND-ASO) for four weeks induced an effective and safe reduction of h-α-Syn synthesis in 5-HT neurons and its accumulation in the forebrain, alleviating early deficits of 5-HT function and improving the behavioural phenotype. Altogether, our findings show that α-synucleinopathy in 5-HT neurons negatively affects brain circuits that control mood and emotions, resembling the expression of neuropsychiatric symptoms occurring at the onset of PD. Early preservation of 5-HT function by reducing α-Syn synthesis/accumulation may alleviate PD-related depressive symptoms.