Simple colour reaction for alkaptonuria

Neurovascular dysfunction and vascular amyloid accumulation as early events in Alzheimer's disease

Alzheimer's disease (AD) is clinically characterized by a progressive loss of cognitive functions and short-term memory. AD patients present two distinctive neuropathological lesions: neuritic plaques and neurofibrillary tangles (NFTs), constituted of beta-amyloid peptide (Aβ) and phosphorylated and truncated tau proteins. Aβ deposits around cerebral blood vessels (cerebral amyloid angiopathy, CAA) is a major contributor to vascular dysfunction in AD. Vascular amyloid deposits could be early events in AD due to dysfunction in the neurovascular unit (NVU) and the blood-brain barrier (BBB), deterioration of the gliovascular unit, and/or decrease of cerebral blood flow (CBF). These pathological events can lead to decreased Aβ clearance, facilitate a neuroinflammatory environment as well as synaptic dysfunction and, finally, lead to neurodegeneration. Here, we review the histopathological AD hallmarks and discuss the two-hit vascular hypothesis of AD, emphasizing the role of neurovascular dysfunction as an early factor that favors vascular Aβ aggregation and neurodegeneration. Addtionally, we emphasize that pericyte degeneration is a key and early element in AD that can trigger amyloid vascular accumulation and NVU/BBB dysfunction. Further research is required to better understand the early pathophysiological mechanisms associated with NVU alteration and CAA to generate early biomarkers and timely treatments for AD.

Trends in kinase drug discovery: targets, indications and inhibitor design

The FDA approval of imatinib in 2001 was a breakthrough in molecularly targeted cancer therapy and heralded the emergence of kinase inhibitors as a key drug class in the oncology area and beyond. Twenty years on, this article analyses the landscape of approved and investigational therapies that target kinases and trends within it, including the most popular targets of kinase inhibitors and their expanding range of indications. There are currently 71 small-molecule kinase inhibitors (SMKIs) approved by the FDA and an additional 16 SMKIs approved by other regulatory agencies. Although oncology is still the predominant area for their application, there have been important approvals for indications such as rheumatoid arthritis, and one-third of the SMKIs in clinical development address disorders beyond oncology. Information on clinical trials of SMKIs reveals that approximately 110 novel kinases are currently being explored as targets, which together with the approximately 45 targets of approved kinase inhibitors represent only about 30% of the human kinome, indicating that there are still substantial unexplored opportunities for this drug class. We also discuss trends in kinase inhibitor design, including the development of allosteric and covalent inhibitors, bifunctional inhibitors and chemical degraders.

Alzheimer's disease in elderly COVID-19 patients: potential mechanisms and preventive measures

Advanced age correlates with higher morbidity and mortality among patients affected with the novel coronavirus disease 2019 (COVID-19). Because systemic inflammation and neurological symptoms are also common in severe COVID-19 cases, there is concern that COVID-19 may lead to neurodegenerative conditions such as Alzheimer’s disease (AD). In this review, we summarize possible mechanisms by which infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, may cause AD in elderly COVID-19 patients and describe preventive measures to mitigate risk. Potential mechanisms include NLRP3 inflammasome activation and IL-1β release, renin-angiotensin system hyperactivation, innate immune activation, oxidative stress, direct viral infection, and direct cytolytic β-cell damage. Anti-inflammatory therapies, including TNF-α inhibitors and nonsteroidal anti-inflammatory drugs, antioxidants such as the vitamin E family, nutritional intervention, physical activity, blood glucose control, and vaccination are proposed as preventive measures to minimize AD risk in COVID-19 patients. Since several risk factors for AD may converge during severe SARS-CoV-2 infection, neurologists should be alert for potential symptoms of AD and actively implement preventive measures in patients presenting with neuropsychiatric symptoms and in high-risk patients such as the elderly.

Physical exercise improves quality of life, depressive symptoms, and cognition across chronic brain disorders: a transdiagnostic systematic review and meta-analysis of randomized controlled trials

We performed a meta-analysis to synthesize evidence on the efficacy and safety of physical exercise as an add-on therapeutic intervention for quality of life (QoL), depressive symptoms and cognition across six chronic brain disorders: Alzheimer's disease, Huntington's disease, multiple sclerosis, Parkinson's disease, schizophrenia and unipolar depression. 122 studies ( = k) (n = 7231) were included. Exercise was superior to treatment as usual in improving QoL (k = 64, n = 4334, ES = 0.40, p < 0.0001), depressive symptoms (k = 60, n = 2909, ES = 0.78, p < 0.0001), the cognitive domains attention and working memory (k = 21, n = 1313, ES = 0.24, p < 0.009), executive functioning (k = 14, n = 977, ES = 0.15, p = 0.013), memory (k = 12, n = 994, ES = 0.12, p = 0.038) and psychomotor speed (k = 16, n = 896, ES = 0.23, p = 0.003). Meta-regression showed a dose-response effect for exercise time (min/week) on depressive symptoms (β = 0.007, p = 0.012). 69% of the studies that reported on safety, found no complications. Exercise is an efficacious and safe add-on therapeutic intervention showing a medium-sized effect on QoL and a large effect on mood in patients with chronic brain disorders, with a positive dose-response correlation. Exercise also improved several cognitive domains with small but significant effects.

Gamma subunit of complement component 8 is a neuroinflammation inhibitor

The complement system is part of the innate immune system that comprises several small proteins activated by sequential cleavages. The majority of these complement components, such as components 3a (C3a) and C5a, are chemotactic and pro-inflammatory. However, in this study, we revealed an inhibitory role of complement component 8 gamma (C8G) in neuroinflammation. In patients with Alzheimer's disease, who exhibit strong neuroinflammation, we found higher C8G levels in brain tissue, CSF, and plasma. Our novel findings also showed that the expression level of C8G increases in the inflamed mouse brain, and that C8G is mainly localized to brain astrocytes. Experiments using recombinant C8G protein and shRNA-mediated knockdown showed that C8G inhibits glial hyperactivation, neuroinflammation, and cognitive decline in acute and chronic animal models of Alzheimer's disease. Additionally, we identified sphingosine-1-phosphate receptor 2 (S1PR2) as a novel interaction protein of C8G and demonstrated that astrocyte-derived C8G interacts with S1PR2 to antagonize the pro-inflammatory action of S1P in microglia. Taken together, our results reveal the previously unrecognized role of C8G as a neuroinflammation inhibitor. Our findings pave the way towards therapeutic containment of neuroinflammation in Alzheimer's disease and related neurological diseases.

Peripheral and central immune system crosstalk in Alzheimer disease - a research prospectus

Dysregulation of the immune system is a cardinal feature of Alzheimer disease (AD), and a considerable body of evidence indicates pathological alterations in central and peripheral immune responses that change over time. Considering AD as a systemic immune process raises important questions about how communication between the peripheral and central compartments occurs and whether this crosstalk represents a therapeutic target. We established a whitepaper workgroup to delineate the current status of the field and to outline a research prospectus for advancing our understanding of peripheral-central immune crosstalk in AD. To guide the prospectus, we begin with an overview of seminal clinical observations that suggest a role for peripheral immune dysregulation and peripheral-central immune communication in AD, followed by formative animal data that provide insights into possible mechanisms for these clinical findings. We then present a roadmap that defines important next steps needed to overcome conceptual and methodological challenges, opportunities for future interdisciplinary research, and suggestions for translating promising mechanistic studies into therapeutic interventions.

Antifungal drug miconazole ameliorated memory deficits in a mouse model of LPS-induced memory loss through targeting iNOS

Alzheimer’s disease (AD) is closely related to neuroinflammation, and the increase in inflammatory cytokine generation and inducible nitric oxide synthase (iNOS) expression in the brain of a patient with AD is well known. Excessive cytokines can stimulate iNOS in microglia and astroglia and overproduce nitric oxide, which can be toxic to neurons. The disease–gene–drug network analysis based on the GWAS/OMIM/DEG records showed that miconazole (MCZ) affected AD through interactions with NOS. Inhibiting iNOS can reduce neuroinflammation, thus preventing AD progression. To investigate the prophylactic role of antifungal agent in the AD development, a lipopolysaccharide-induced memory disorder mouse model was used, and cognitive function was assessed by Morris water maze test and passive avoidance test. MCZ treatment significantly attenuated cognitive impairment, suppressed iNOS and cyclooxygenase-2 expression, and activation of astrocyte and microglial BV2 cells, as well as reduced cytokine levels in the brains and lipopolysaccharide-treated astrocytes and microglia BV2 cells. In further mechanism studies, Pull-down assay and iNOS luciferase activity data showed that MCZ binds to iNOS and inhibited transcriptional activity. Our results suggest that MCZ is useful for ameliorating the neuroinflammation-mediated AD progression by blocking iNOS expression.

Neuroinflammation in dementia with Lewy bodies: a human post-mortem study

Dementia with Lewy bodies (DLB) is the second most common neurodegenerative cause of dementia, behind Alzheimer's disease (AD). It is now established that cerebral inflammation has a key role in the aetiology and progression of AD, but this has yet to be confirmed in DLB. We aimed to determine the neuroinflammatory profile in the cerebral cortex of a large cohort of DLB cases. Thirty post-mortem confirmed DLB cases and twenty-nine matched controls were immunolabelled (Brodmann area 21) and quantified for: neuropathology-αSYN, Aβ, P-tau; microglial phenotype-Iba1, HLA-DR, CD68, FcƴR (CD64, CD32a, CD32b, CD16); presence of T lymphocytes-CD3; and anti-inflammatory markers-IL4R, CHI3L1. Status spongiosis, as a marker of neuropil degeneration, was quantified using Haematoxylin and Eosin staining. We found no significant difference between groups in protein load for Iba1, HLA-DR, CD68, CD64, CD32b, IL4R, or CHI3L1, despite increased neuropathology in DLB. CD32a load was significantly lower, and CD16 load higher, in DLB compared with controls. There was no difference in status spongiosis between groups. Significantly more DLB cases than controls showed T-lymphocyte recruitment. Overall, we conclude that microglial activation is not a prominent feature of DLB, and that this may be associated with the relatively modest neuropil degeneration observed in DLB. Our findings, based on the largest post-mortem cohort to date exploring neuroinflammation in DLB, demonstrate a dissociation between protein deposition, neurodegeneration and microglial activation. The relative preservation of cortical structures in DLB suggests the dementia could be more amenable to potential therapies.

Systemic loss of Sarm1 protects Schwann cells from chemotoxicity by delaying axon degeneration

Protecting the nervous system from chronic effects of physical and chemical stress is a pressing clinical challenge. The obligate pro-degenerative protein Sarm1 is essential for Wallerian axon degeneration. Thus, blocking Sarm1 function is emerging as a promising neuroprotective strategy with therapeutic relevance. Yet, the conditions that will most benefit from inhibiting Sarm1 remain undefined. Here we combine genome engineering, pharmacology and high-resolution intravital videmicroscopy in zebrafish to show that genetic elimination of Sarm1 increases Schwann-cell resistance to toxicity by diverse chemotherapeutic agents after axonal injury. Synthetic degradation of Sarm1-deficient axons reversed this effect, suggesting that glioprotection is a non-autonomous effect of delayed axon degeneration. Moreover, loss of Sarm1 does not affect macrophage recruitment to nerve-wound microenvironment, injury resolution, or neural-circuit repair. These findings anticipate that interventions aimed at inhibiting Sarm1 can counter heightened glial vulnerability to chemical stressors and may be an effective strategy to reduce chronic consequences of neurotrauma.

A Founder Effect for the HGD G360R Mutation in Italy: Implications for a Regional Screening of Alkaptonuria

We sought to establish rapid and specific genotyping methods for G360R mutation and for seven tightly linked markers in the homogentisate dioxygenase gene to address the question of whether G360R is a mutational hot spot or the result of a founder effect, as it has been repeatedly found in alkaptonuric patients from a geographic isolate in Italy.For G360R and single nucleotide polymorphism genotyping, high-resolution melting analysis was performed. Microsatellites were analysed by multiplex PCR and capillary electrophoresis. To investigate the natural history of the G360R mutation, we genotyped markers in 52 controls and in 8 unrelated patients from the UK and USA, who also segregated the G360R mutation, and calculated its age using DMLE+2.3 software.A distinct G360R-bearing haplotype was identified in all patients of Caucasian descent. Estimated mutation age was 545 generations (95% credible set, 402-854), suggesting that G360R arose in an ancestor who lived 8,000-10,000 years BC. Archaeological, historical and demographic data support that a G360R carrier has settled the remote valley where present-day population might have a heterozygote frequency of at least 6%.Given the late health-threatening complications of alkaptonuria and a cure within reach, inhabitants of this isolate would benefit from screening and genetic counselling.