SARS-CoV-2-Mimicking Pseudoviral Particles Accelerate α-Synuclein Aggregation In Vitro.

Since the SARS-CoV-2 virus started spreading worldwide, evidence pointed toward an impact of the infection on the nervous system. COVID-19 patients present neurological manifestations and have an increased risk of developing brain-related symptoms in the long term. In fact, evidence in support of the neuroinvasive potential of SARS-CoV-2 has emerged. Considering that viral parkisonism was observed as a consequence of encephalopathies caused by viral infections, it has been already suggested that COVID-19 could affect the dopaminergic neurons and contribute to neurodegeneration in Parkinson's disease (PD), by promoting the formation of amyloid fibrils constituted by the PD-related protein α-synuclein. Here, we observe not only that SARS-CoV-2 viral spike protein and nucleocapsid protein can alone promote α-synuclein aggregation but also that the spike protein organization in a corona shape on the viral envelope may be crucial in triggering fast amyloid fibrils formation, thus possibly contributing to PD pathogenesis.

Impact of bacterial infections prior to liver transplantation on post-transplant outcomes in patients with cirrhosis.

Background & Aims: Bacterial infections are frequent in patients with cirrhosis and increase the risk of death and drop-out from liver transplant (LT) waiting list. In patients with bacterial infections, LT is frequently delayed because of the fear of poor outcomes. We evaluated the impact of pre-LT infections on post-LT complications and survival. Methods: From 2012 to 2018, consecutive patients transplanted at the Hospital of Padua were identified and classified in two groups: patients surviving an episode of bacterial infection within 3 months before LT (study group) and patients without infections before LT (control group). Post-LT outcomes (complications, new infections, survival) were collected. Results: A total of 466 LT recipients were identified (study group n = 108; control group n = 358). After LT, the study group had a higher incidence of new bacterial (57% vs. 20%, p <0.001) and fungal infections (14% vs. 5%, p = 0.001) and of septic shock (8% vs. 2%, p = 0.004) than the control group. Along with the model for end-stage liver disease (MELD) score and alcohol-related cirrhosis, bacterial infection pre-LT was an independent predictor of post-LT infections (odds ratio = 3.92; p <0.001). Nevertheless, no significant difference was found in 1-year (88% vs. 89%, p = 0.579) and 5-year survival rates (76% vs. 75%, p = 0.829) between the study group and control group. Within the study group, no association was found between the time elapsed from infection improvement/resolution to LT and post-LT outcomes. Conclusions: Patients with pre-LT infections have a higher risk of new bacterial and fungal infections and of septic shock after LT. However, post-LT survival is excellent. Therefore, as soon as the bacterial infection is improving/resolving, transplant should not be delayed, but patients with pre-transplant bacterial infections require active surveillance for infections after LT. Impact and Implications: Bacterial infections increase mortality and delay transplant in patients with cirrhosis awaiting liver transplantation (LT). Little is known about the impact of adequately treated infections before LT on post-transplant complications and outcomes. The study highlights that pre-LT infections increase the risk of post-LT infections, but post-LT survival rates are excellent despite the risk. These findings suggest that physicians should not delay LT because of concerns about pre-LT infections, but instead should actively monitor these patients for infections after surgery.

LRRK2 kinase activity regulates GCase level and enzymatic activity differently depending on cell type in Parkinson's disease.

Leucine-rich repeat kinase 2 (LRRK2) is a kinase involved in different cellular functions, including autophagy, endolysosomal pathways, and immune function. Mutations in LRRK2 cause autosomal-dominant forms of Parkinson's disease (PD). Heterozygous mutations in GBA1, the gene encoding the lysosomal enzyme glucocerebrosidase (GCase), are the most common genetic risk factors for PD. Moreover, GCase function is altered in idiopathic PD and in other genetic forms of the disease. Recent work suggests that LRRK2 kinase activity can regulate GCase function. However, both a positive and a negative correlation have been described. To gain insights into the impact of LRRK2 on GCase, we performed a comprehensive analysis of GCase levels and activity in complementary LRRK2 models, including (i) LRRK2 G2019S knock in (GSKI) mice, (ii) peripheral blood mononuclear cell (PBMCs), plasma, and fibroblasts from PD patients carrying LRRK2 G2019S mutation, (iii) patient iPSCs-derived neurons; (iv) endogenous and overexpressed cell models. In some of these models we found a positive correlation between the activities of LRRK2 and GCase, which was further confirmed in cell lines with genetic and pharmacological manipulation of LRRK2 kinase activity. GCase protein level is reduced in GSKI brain tissues and in G2019S iPSCs-derived neurons, but increased in fibroblasts and PBMCs from patients, suggesting cell-type-specific effects. Overall, our study indicates that LRRK2 kinase activity affects both the levels and the catalytic activity of GCase in a cell-type-specific manner, with important implications in the context of therapeutic application of LRRK2 inhibitors in GBA1-linked and idiopathic PD.