Autophagy, a major degradation process for long-lived and aggregate-prone proteins, affects various human processes, such as development, immunity, cancer, and neurodegeneration. Several autophagy ...regulators have been identified in recent years. Here we show that nitric oxide (NO), a potent cellular messenger, inhibits autophagosome synthesis via a number of mechanisms. NO impairs autophagy by inhibiting the activity of S-nitrosylation substrates, JNK1 and IKKβ. Inhibition of JNK1 by NO reduces Bcl-2 phosphorylation and increases the Bcl-2–Beclin 1 interaction, thereby disrupting hVps34/Beclin 1 complex formation. Additionally, NO inhibits IKKβ and reduces AMPK phosphorylation, leading to mTORC1 activation via TSC2. Overexpression of nNOS, iNOS, or eNOS impairs autophagosome formation primarily via the JNK1–Bcl-2 pathway. Conversely, NOS inhibition enhances the clearance of autophagic substrates and reduces neurodegeneration in models of Huntington's disease. Our data suggest that nitrosative stress-mediated protein aggregation in neurodegenerative diseases may be, in part, due to autophagy inhibition.
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► NO inhibits autophagy by independently inhibiting JNK1 and IKKβ ► NO inhibits autophagic flux via mTOR and mTOR-independent routes ► NOS overexpression impairs autophagosome synthesis via JNK1–Bcl-2 pathway ► NOS inhibition induces autophagy and protects against neurodegeneration
Huntington's disease is a late-onset neurodegenerative disease caused by a CAG trinucleotide repeat in the gene encoding the huntingtin protein. Despite its well-defined genetic origin, the molecular ...and cellular mechanisms underlying the disease are unclear and complex. Here, we review some of the currently known functions of the wild-type huntingtin protein and discuss the deleterious effects that arise from the expansion of the CAG repeats, which are translated into an abnormally long polyglutamine tract. Finally, we outline some of the therapeutic strategies that are currently being pursued to slow down the disease.
Dementia is the leading cause of death in elderly Western populations. Preventative interventions that could delay dementia onset even modestly would provide a major public health impact. There are ...no disease-modifying treatments currently available. Lithium has been proposed as a potential treatment. We assessed the association between lithium use and the incidence of dementia and its subtypes.
We conducted a retrospective cohort study comparing patients treated between January 1, 2005 and December 31, 2019, using data from electronic clinical records of secondary care mental health (MH) services in Cambridgeshire and Peterborough NHS Foundation Trust (CPFT), United Kingdom (catchment area population approximately 0.86 million). Eligible patients were those aged 50 years or over at baseline and who had at least 1 year follow-up, excluding patients with a diagnosis of mild cognitive impairment (MCI) or dementia before, or less than 1 year after, their start date. The intervention was the use of lithium. The main outcomes were dementia and its subtypes, diagnosed and classified according to the International Classification of Diseases-10th Revision (ICD-10). In this cohort, 29,618 patients (of whom 548 were exposed to lithium) were included. Their mean age was 73.9 years. A total of 40.2% were male, 33.3% were married or in a civil partnership, and 71.0% were of white ethnicity. Lithium-exposed patients were more likely to be married, cohabiting or in a civil partnership, to be a current/former smoker, to have used antipsychotics, and to have comorbid depression, mania/bipolar affective disorder (BPAD), hypertension, central vascular disease, diabetes mellitus, or hyperlipidemias. No significant difference between the 2 groups was observed for other characteristics, including age, sex, and alcohol-related disorders. In the exposed cohort, 53 (9.7%) patients were diagnosed with dementia, including 36 (6.8%) with Alzheimer disease (AD) and 13 (2.6%) with vascular dementia (VD). In the unexposed cohort, corresponding numbers were the following: dementia 3,244 (11.2%), AD 2,276 (8.1%), and VD 698 (2.6%). After controlling for sociodemographic factors, smoking status, other medications, other mental comorbidities, and physical comorbidities, lithium use was associated with a lower risk of dementia (hazard ratio HR 0.56, 95% confidence interval CI 0.40 to 0.78), including AD (HR 0.55, 95% CI 0.37 to 0.82) and VD (HR 0.36, 95% CI 0.19 to 0.69). Lithium appeared protective in short-term (≤1-year exposure) and long-term lithium users (>5-year exposure); a lack of difference for intermediate durations was likely due to lack of power, but there was some evidence for additional benefit with longer exposure durations. The main limitation was the handling of BPAD, the most common reason for lithium prescription but also a risk factor for dementia. This potential confounder would most likely cause an increase in dementia in the exposed group, whereas we found the opposite, and the sensitivity analysis confirmed the primary results. However, the specific nature of the group of patients exposed to lithium means that caution is needed in extending these findings to the general population. Another limitation is that our sample size of patients using lithium was small, reflected in the wide CIs for results relating to some durations of lithium exposure, although again sensitivity analyses remained consistent with our primary findings.
We observed an association between lithium use and a decreased risk of developing dementia. This lends further support to the idea that lithium may be a disease-modifying treatment for dementia and that this is a promising treatment to take forwards to larger randomised controlled trials (RCTs) for this indication.
(Macro)autophagy is a bulk degradation process that mediates the clearance of long-lived proteins and organelles. Autophagy is initiated by double-membraned structures, which engulf portions of ...cytoplasm. The resulting autophagosomes ultimately fuse with lysosomes, where their contents are degraded. Although the term autophagy was first used in 1963, the field has witnessed dramatic growth in the last 5 years, partly as a consequence of the discovery of key components of its cellular machinery. In this review we focus on mammalian autophagy, and we give an overview of the understanding of its machinery and the signaling cascades that regulate it. As recent studies have also shown that autophagy is critical in a range of normal human physiological processes, and defective autophagy is associated with diverse diseases, including neurodegeneration, lysosomal storage diseases, cancers, and Crohn's disease, we discuss the roles of autophagy in health and disease, while trying to critically evaluate if the coincidence between autophagy and these conditions is causal or an epiphenomenon. Finally, we consider the possibility of autophagy upregulation as a therapeutic approach for various conditions.
Huntington's disease (HD) is a devastating autosomal dominant neurodegenerative disease caused by a CAG trinucleotide repeat expansion encoding an abnormally long polyglutamine tract in the ...huntingtin protein. Much has been learnt since the mutation was identified in 1993. We review the functions of wild-type huntingtin. Mutant huntingtin may cause toxicity via a range of different mechanisms. The primary consequence of the mutation is to confer a toxic gain of function on the mutant protein and this may be modified by certain normal activities that are impaired by the mutation. It is likely that the toxicity of mutant huntingtin is revealed after a series of cleavage events leading to the production of N-terminal huntingtin fragment(s) containing the expanded polyglutamine tract. Although aggregation of the mutant protein is a hallmark of the disease, the role of aggregation is complex and the arguments for protective roles of inclusions are discussed. Mutant huntingtin may mediate some of its toxicity in the nucleus by perturbing specific transcriptional pathways. HD may also inhibit mitochondrial function and proteasome activity. Importantly, not all of the effects of mutant huntingtin may be cell-autonomous, and it is possible that abnormalities in neighbouring neurons and glia may also have an impact on connected cells. It is likely that there is still much to learn about mutant huntingtin toxicity, and important insights have already come and may still come from chemical and genetic screens. Importantly, basic biological studies in HD have led to numerous potential therapeutic strategies.
Objectives
Personality disorders (PDs) are often conceptualised as impacting individuals throughout their life. However, there has been limited study of the disorders in those over the age of 65. We ...have used the psychiatric secondary care medical records of 21,971 individuals over the age of 65 from Cambridgeshire, UK, who received care between 2014 and 2021 to characterise older patients with a PD diagnosis.
Methods
The data from all patients >65 with a diagnosis of personality disorder (PD) was extracted (n = 217) along with two comparison groups (n = 2170); patients <65 with a diagnosis of PD and patients >65 with a psychiatric diagnosis other than PD or dementia.
Results
Compared to younger patients with PD, older patients were more likely to be male, married, suffering from a mixed PD and live in less deprived areas. Compared to patients >65 with diagnoses other than PD, older patients were more likely to be female, single or divorced and had a higher level of social deprivation. Our most striking finding was that older patients with PDs were more likely to experience polypharmacy. A mean of 18.48 different drugs had been prescribed over their lifetime, compared to 9.51 for patients >65 with other mental health diagnoses.
Conclusion
Here we present the largest ever description of this group of patients and provide insights that could inform clinical practice and future research.
Key points
Using the electronic healthcare records of a population of nearly 1 million people, we have shown patients >65 with a diagnosis of personality disorder (PD) to be a group with distinct characteristics compared to younger patients with PD and older patients with other mental health diagnoses.
The number receiving care is much smaller than expected based on studies of the general population, which may indicate unmet need.
Patients in this group show improvement in their Health of the Nation Outcome Scales scores following treatment in NHS mental health services.
Older people with a diagnosis of PD received double the number of diagnoses and different prescription medications in their lifetime compared to patients of the same age with other psychiatric diagnoses, raising the possibility that interventions such as a medication review might be helpful.
COVID-19 has affected social interaction and healthcare worldwide.
We examined changes in presentations and referrals to the primary provider of mental health and community health services in ...Cambridgeshire and Peterborough, UK (population ~0·86 million), plus service activity and deaths. We conducted interrupted time series analyses with respect to the time of UK “lockdown”, which was shortly before the peak of COVID-19 infections in this area. We examined changes in standardized mortality ratio for those with and without severe mental illness (SMI).
Referrals and presentations to nearly all mental and physical health services dropped at lockdown, with evidence for changes in both supply (service provision) and demand (help-seeking). This was followed by an increase in demand for some services. This pattern was seen for all major forms of presentation to liaison psychiatry services, except for eating disorders, for which there was no evidence of change. Inpatient numbers fell, but new detentions under the Mental Health Act were unchanged. Many services shifted from face-to-face to remote contacts. Excess mortality was primarily in the over-70s. There was a much greater increase in mortality for patients with SMI, which was not explained by ethnicity.
COVID-19 has been associated with a system-wide drop in the use of mental health services, with some subsequent return in activity. “Supply” changes may have reduced access to mental health services for some. “Demand” changes may reflect a genuine reduction of need or a lack of help-seeking with pent-up demand. There has been a disproportionate increase in death among those with SMI during the pandemic.
Abstract
Given considerable variation in diagnostic and therapeutic practice, there is a need for national guidance on the use of neuroimaging, fluid biomarkers, cognitive testing, follow-up and ...diagnostic terminology in mild cognitive impairment (MCI). MCI is a heterogenous clinical syndrome reflecting a change in cognitive function and deficits on neuropsychological testing but relatively intact activities of daily living. MCI is a risk state for further cognitive and functional decline with 5–15% of people developing dementia per year. However, ~50% remain stable at 5 years and in a minority, symptoms resolve over time. There is considerable debate about whether MCI is a useful clinical diagnosis, or whether the use of the term prevents proper inquiry (by history, examination and investigations) into underlying causes of cognitive symptoms, which can include prodromal neurodegenerative disease, other physical or psychiatric illness, or combinations thereof. Cognitive testing, neuroimaging and fluid biomarkers can improve the sensitivity and specificity of aetiological diagnosis, with growing evidence that these may also help guide prognosis. Diagnostic criteria allow for a diagnosis of Alzheimer’s disease to be made where MCI is accompanied by appropriate biomarker changes, but in practice, such biomarkers are not available in routine clinical practice in the UK. This would change if disease-modifying therapies became available and required a definitive diagnosis but would present major challenges to the National Health Service and similar health systems. Significantly increased investment would be required in training, infrastructure and provision of fluid biomarkers and neuroimaging. Statistical techniques combining markers may provide greater sensitivity and specificity than any single disease marker but their practical usefulness will depend on large-scale studies to ensure ecological validity and that multiple measures, e.g. both cognitive tests and biomarkers, are widely available for clinical use. To perform such large studies, we must increase research participation amongst those with MCI.
Dementia with Lewy bodies (DLB) is the underlying aetiology of 10-15% of all cases of dementia and as such is a clinically important diagnosis. In the past few years, substantial advances have been ...made in understanding the genetics and pathology of this condition. For example, research has expanded our knowledge of the proteinaceous inclusions that characterize the disease, has provided an appreciation of the role of disease-associated processes such as inflammation and has revealed an association between DLB and genes such as GBA. These insights might have broader relevance to other neurodegenerative conditions and are beginning to be translated into clinical trials. In this Review, we provide clinical insights for the basic scientist and a basic science foundation for the clinician. We discuss the history of the condition; the definition of DLB; the relationship between DLB and other neurodegenerative conditions; current understanding of the pathology, genetics, clinical presentation and diagnosis of DLB; options for treatment; and potential future directions for research.
Many neurodegenerative diseases are caused by intracellular, aggregate-prone proteins, including polyglutamine-expanded huntingtin in Huntington's disease (HD) and mutant tau in fronto-temporal ...dementia/tauopathy. Previously, we showed that rapamycin, an autophagy inducer, enhances mutant huntingtin fragment clearance and attenuated toxicity. Here we show much wider applications for this approach. Rapamycin enhances the autophagic clearance of different proteins with long polyglutamines and a polyalanine-expanded protein, and reduces their toxicity. Rapamycin also reduces toxicity in Drosophila expressing wild-type or mutant forms of tau and these effects can be accounted for by reductions in insoluble tau. Thus, our studies suggest that the scope for rapamycin as a potential therapeutic in aggregate diseases may be much broader than HD or even polyglutamine diseases.
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