Activation of parkin by a molecular glue.

Mutations in parkin and PINK1 cause early-onset Parkinson's disease (EOPD). The ubiquitin ligase parkin is recruited to damaged mitochondria and activated by PINK1, a kinase that phosphorylates ubiquitin and the ubiquitin-like domain of parkin. Activated phospho-parkin then ubiquitinates mitochondrial proteins to target the damaged organelle for degradation. Here, we present the mechanism of activation of a new class of small molecule allosteric modulators that enhance parkin activity. The compounds act as molecular glues to enhance the ability of phospho-ubiquitin (pUb) to activate parkin. Ubiquitination assays and isothermal titration calorimetry with the most active compound (BIO-2007817) identify the mechanism of action. We present the crystal structure of a closely related compound (BIO-1975900) bound to a complex of parkin and two pUb molecules. The compound binds next to pUb on RING0 and contacts both proteins. Hydrogen-deuterium exchange mass spectrometry (HDX-MS) experiments confirm that activation occurs through release of the catalytic Rcat domain. In organello and mitophagy assays demonstrate that BIO-2007817 partially rescues the activity of parkin EOPD mutants, R42P and V56E, offering a basis for the design of activators as therapeutics for Parkinson's disease.

Predicting Age from White Matter Diffusivity with Residual Learning.

Imaging findings inconsistent with those expected at specific chronological age ranges may serve as early indicators of neurological disorders and increased mortality risk. Estimation of chronological age, and deviations from expected results, from structural magnetic resonance imaging (MRI) data has become an important proxy task for developing biomarkers that are sensitive to such deviations. Complementary to structural analysis, diffusion tensor imaging (DTI) has proven effective in identifying age-related microstructural changes within the brain white matter, thereby presenting itself as a promising additional modality for brain age prediction. Although early studies have sought to harness DTI's advantages for age estimation, there is no evidence that the success of this prediction is owed to the unique microstructural and diffusivity features that DTI provides, rather than the macrostructural features that are also available in DTI data. Therefore, we seek to develop white-matter-specific age estimation to capture deviations from normal white matter aging. Specifically, we deliberately disregard the macrostructural information when predicting age from DTI scalar images, using two distinct methods. The first method relies on extracting only microstructural features from regions of interest (ROIs). The second applies 3D residual neural networks (ResNets) to learn features directly from the images, which are non-linearly registered and warped to a template to minimize macrostructural variations. When tested on unseen data, the first method yields mean absolute error (MAE) of 6.11 ± 0.19 years for cognitively normal participants and MAE of 6.62 ± 0.30 years for cognitively impaired participants, while the second method achieves MAE of 4.69 ± 0.23 years for cognitively normal participants and MAE of 4.96 ± 0.28 years for cognitively impaired participants. We find that the ResNet model captures subtler, non-macrostructural features for brain age prediction.

Brain age is not a significant predictor of relapse risk in late-life depression.

INTRODUCTION: Late-life depression (LLD) has been associated cross-sectionally with lower brain structural volumes and accelerated brain aging compared to healthy controls (HC). There are few longitudinal studies on the neurobiological predictors of recurrence in LLD. We tested a machine learning (ML) brain age model and its prospective association with LLD recurrence risk. METHODS: We recruited individuals with LLD (n=102) and HC (n=43) into a multi-site 2-yr longitudinal study. Individuals with LLD were enrolled within 4 months of remission. Remitted LLD participants underwent baseline neuroimaging and longitudinal clinical follow-up. Over 2 years, 43 LLD participants relapsed (REL) and 59 stayed in remission (REM). We used a previously developed ML brain age algorithm to compute brain age at baseline and we evaluated brain age group differences (HC vs. LLD and HC vs. REM vs. REL). We conducted a Cox proportional hazards model to evaluate whether baseline brain age predicted time to relapse. RESULTS: We found that brain age did not significantly differ between HC and LLD as well as HC, REM, and REL groups. Brain age did not significantly predict time to relapse. DISCUSSION: In contrast to our hypothesis, we found that brain age did not differ between non-depressed controls and individuals with remitted LLD, and brain age was not associated with subsequent recurrence. This is in contrast to existing literature which has identified baseline brain age differences in late life but in line with work that shows no differences between those who do and do not relapse on gross structural measures.

Stroke Prevention and Treatment for Youth with Sickle Cell Anemia: Current Practice and Challenges and Promises for the Future.

PURPOSE OF REVIEW: Sickle cell anemia (SCA) is an autosomal recessive inherited hemoglobinopathy that results in a high risk of stroke. SCA primarily affects an underserved minority population of children who are frequently not receiving effective, multi-disciplinary, preventative care. This article reviews primary and secondary stroke prevention and treatment for children with SCA for the general adult and pediatric neurologist, who may play an important role in providing critical neurologic evaluation and care to these children. RECENT FINDINGS: Primary stroke prevention is efficacious at reducing ischemic stroke risk, but it is not consistently implemented into clinical practice in the United States, resulting in these children remaining at high risk. Acute symptomatic stroke management requires neurology involvement and emergent transfusion to limit ischemia. Furthermore, while chronic transfusion therapy is a proven secondary preventative modality for those with prior symptomatic or silent cerebral infarcts, it carries significant burden. Newer therapies (e.g., stem cell therapies and voxelotor) deserve further study as they may hold promise in reducing stroke risk and treatment burden. Effective primary and secondary stroke prevention and treatment remain a challenge. Informing and engaging neurology providers to recognize and provide critical neurologic evaluation and treatment has potential to close care gaps.

ASO-mediated knockdown of GPNMB in mutant- GRN and Grn -deficient peripheral myeloid cells disrupts lysosomal function and immune responses.

Background: Increases in GPNMB are detectable in FTD- GRN cerebrospinal fluid (CSF) and post-mortem brain, and brains of aged Grn -deficient mice. Although no upregulation of GPNMB is observed in the brains of young Grn -deficient mice, peripheral immune cells of these mice do exhibit this increase in GPNMB. Importantly, the functional significance of GPNMB upregulation in progranulin-deficient states is currently unknown. Given that GPNMB has been discussed as a potential therapeutic target in GRN -mediated neurodegeneration, it is vital for the field to determine what the normal function of GPNMB is in the immune system, and whether targeting GPNMB will elicit beneficial or deleterious effects. Methods: The effects of GPNMB knock-down via antisense oligonucleotide (ASO) were assessed in peripheral blood mononuclear cells (PBMCs) from 25 neurologically healthy controls (NHCs) and age- and sex-matched FTD- GRN patients, as well as peritoneal macrophages (pMacs) from progranulin-deficient ( Grn -/- ) and B6 mice. Lysosomal function, antigen presentation and MHC-II processing and recycling were assessed, as well as cytokine release and transcription. Results: We demonstrate here that ASO-mediated knockdown of GPNMB increases lysosomal burden and cytokine secretion in FTD-GRN carrier and neurologically healthy controls (NHCs) monocytes. ASO-mediated knockdown of GPNMB in Grn -deficient macrophages decreased lysosomal pan-cathepsin activity and protein degradation. In addition, ASO-mediated knockdown of GPNMB increased MHC-II surface expression, which was driven by decreased MHC-II uptake and recycling, in macrophages from Grn -deficient females. Finally, ASO-mediated knockdown of GPNMB dysregulated IFNγ-stimulated cytokine transcription and secretion by mouse macrophages due to the absence of regulatory actions of the GPNMB extracellular fragment (ECF). Conclusions: Our data herein reveals that GPNMB has a regulatory effect on multiple immune effector functions, including capping inflammation and immune responses in myeloid cells via secretion of its ECF. Therefore, in progranulin-deficient states, the drastic upregulation in GPNMB transcript and protein may represent a compensatory mechanism to preserve lysosomal function in myeloid cells. These novel findings indicate that targeted depletion in FTD- GRN would not be a rational therapeutic strategy because it is likely to dysregulate important immune cell effector functions.

The relationship of mental health symptoms to chemotherapy toxicity risk in older adults with cancer: Results from the geriatric assessment-driven intervention study.

BACKGROUND: Depression and anxiety are prevalent in older adults with cancer but are often undertreated. Older adults are also at increased risk of chemotherapy toxicity (CT). This study evaluated the impact of depression and anxiety symptoms on severe CT risk in older adults with cancer. METHODS: This is a secondary analysis of a randomized trial (2:1) evaluating geriatric assessment-driven intervention (GAIN) versus standard of care (SOC) to reduce grade 3+ CT in older adults with cancer. Mental health was assessed via the Mental Health Inventory 13. CT was graded by National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0. RESULTS: A total of 605 patients enrolled (402 GAIN; 203 SOC). Overall, 35% were depressed and 47% were anxious. Patients with depression had increased CT in the SOC arm (70.7% vs. 54.3%; p = .02) but not in the GAIN arm (54.3% vs. 48.5%; p = .27). CT was more likely in SOC patients with depression (odds ratio [OR], 2.03; 95% CI, 1.10-3.72). This association persisted after adjusting for Cancer and Aging Research Group toxicity score (OR, 1.98; 95% CI, 1.07-3.65) and for demographic, disease, and treatment factors (OR, 2.00; 95% CI, 1.03-3.85). Depression and CT were not associated in the GAIN arm (OR, 1.26; 95% CI, 0.84-1.91). Anxiety and CT were not associated in either arm. CONCLUSIONS: Elevated depression symptoms are associated with increased risk of severe CT in older adults with cancer, which was mitigated with GAIN. This suggests that treating depression symptoms may lower toxicity risk. Future studies are needed to confirm and investigate the impact of depression-specific interventions on outcomes.

Effects of open-label transdermal nicotine antidepressant augmentation on affective symptoms and executive function in late-life depression.

BACKGROUND: Late-life depression (LLD) is characterized by a poor response to antidepressant medications and diminished cognitive performance, particularly in executive functioning. There is currently no accepted pharmacotherapy for LLD that effectively treats both mood and cognitive symptoms. This study investigated whether transdermal nicotine augmentation of standard antidepressant medications benefitted mood and cognitive symptoms in LLD. METHODS: Nonsmoking participants aged 60 years or older with unremitted LLD on stable SSRI or SNRI medications (N = 29) received transdermal nicotine patches up to a 21 mg daily dose over 12 weeks. Clinical measures assessed depression severity, secondary affective symptoms, and cognitive performance. Nicotine metabolite concentrations were obtained from blood samples. RESULTS: Depression severity significantly decreased over the trial, with a 76 % response rate and 59 % remission rate. Change in depression severity was positively associated with nicotine exposure. Participants also exhibited improvement in self-reported affective symptoms (apathy, insomnia, rumination, and generalized anxiety symptoms), negativity bias, and disability. Executive function test performance significantly improved, specifically in measures of cognitive control, as did subjective cognitive performance. Adverse events were generally mild, with 75 % of the sample tolerating the maximum dose. CONCLUSION: The current study extends our previous pilot open-label trial in LLD, supporting feasibility and tolerability of transdermal nicotine patches as antidepressant augmentation. Although preliminary, this open-label study supports the potential benefit of transdermal nicotine patches for both mood and cognitive symptoms of LLD. Further research, including definitive randomized, blinded trials, is warranted to confirm these findings and explore long-term risk and benefit. TRIAL REGISTRATION: The study was registered with clinicaltrials.gov (NCT04433767).

Real-time detection of enzymatically formed hydrogen sulfide by pathogenic variants of cystathionine beta-synthase using hemoglobin I of Lucina pectinata as a biosensor.

Classical homocystinuria is a rare disease caused by mutations in cystathionine ß-synthase (CBS) gene (OMIM 613381). CBS catalyzes the first step of the transsulfuration pathway that converts homocysteine (Hcy) into cystathionine (Cysta) via a number of co-substrates and mechanisms. Formation of Cysta by condensation of Hcy and cysteine (Cys) produces a molar equivalent of hydrogen sulfide (H2S). H2S plays important roles in cognitive and vascular functions. Clinically, patients with CBS deficiency present with vascular, ocular, neurological and skeletal impairments. Biochemically, CBS deficiency manifests with elevated Hcy and reduced concentration of Cysta in plasma and urine. A number of pathogenic variants of human CBS have been characterized by their residual enzymatic activity, but very few studies have examined H2S production by pathogenic CBS variants, possibly due to technical hurdles in H2S detection and quantification. We describe a method for the real-time, continuous quantification of H2S formed by wild-type and pathogenic variants of human recombinant CBS, as well as by fibroblast extracts from healthy controls and patients diagnosed with CBS deficiency. The method takes advantage of the specificity and high affinity of hemoglobin I of the clam Lucina pectinata toward H2S and is based on UV-visible spectrophotometry. Comparison with the gold-standard, end-point H2S quantification method employing monobromobimane, as well as correlations with CBS enzymatic activity determined by LC-MS/MS showed agreement and correlation, and permitted the direct, time-resolved determination of H2S production rates by purified human recombinant CBS and by CBS present in fibroblast extracts. Rates of H2S production were highest for wild-type CBS, and lower for pathogenic variants. This method enables the examination of structural determinants of CBS that are important for H2S production and its possible relevance to the clinical outcome of patients.

RIT2 regulates autophagy lysosomal pathway induction and protects against α-synuclein pathology in a cellular model of Parkinson's disease.

Substantial work has been devoted to better understand the contribution of the myriad of genes that may underly the development of Parkinson's disease (PD) and their role in disease etiology. The small GTPase Ras-like without CAAX2 (RIT2) is one such genetic risk factor, with one single nucleotide polymorphism in the RIT2 locus, rs12456492, having been associated with PD risk in multiple populations. While RIT2 has previously been shown to influence signaling pathways, dopamine transporter trafficking, and LRRK2 activity, its cellular function remains unclear. In the current study, we have situated RIT2 to be upstream of various diverse processes associated with PD. In cellular models, we have shown that RIT2 is necessary for activity-dependent changes in the expression of genes related to the autophagy-lysosomal pathway (ALP) by regulating the nuclear translocation of MiT/TFE3-family transcription factors. RIT2 is also associated with lysosomes and can regulate autophagic flux and clearance by regulating lysosomal hydrolase expression and activity. Interestingly, upregulation of RIT2 can augment ALP flux and protect against α-synuclein aggregation in cortical neurons. Taken together, the present study suggests that RIT2 can regulates gene expression upstream of ALP function and that enhancing RIT2 activity may provide therapeutic benefit in PD.

Deciphering pathophysiological mechanisms underlying cystathionine beta-synthase-deficient homocystinuria using targeted metabolomics, liver proteomics, sphingolipidomics and analysis of mitochondrial function.

BACKGROUND: Cystathionine ß-synthase (CBS)-deficient homocystinuria (HCU) is an inherited disorder of sulfur amino acid metabolism with varying severity and organ complications, and a limited knowledge about underlying pathophysiological processes. Here we aimed at getting an in-depth insight into disease mechanisms using a transgenic mouse model of HCU (I278T). METHODS: We assessed metabolic, proteomic and sphingolipidomic changes, and mitochondrial function in tissues and body fluids of I278T mice and WT controls. Furthermore, we evaluated the efficacy of methionine-restricted diet (MRD) in I278T mice. RESULTS: In WT mice, we observed a distinct tissue/body fluid compartmentalization of metabolites with up to six-orders of magnitude differences in concentrations among various organs. The I278T mice exhibited the anticipated metabolic imbalance with signs of an increased production of hydrogen sulfide and disturbed persulfidation of free aminothiols. HCU resulted in a significant dysregulation of liver proteome affecting biological oxidations, conjugation of compounds, and metabolism of amino acids, vitamins, cofactors and lipids. Liver sphingolipidomics indicated upregulation of the pro-proliferative sphingosine-1-phosphate signaling pathway. Liver mitochondrial function of HCU mice did not seem to be impaired compared to controls. MRD in I278T mice improved metabolic balance in all tissues and substantially reduced dysregulation of liver proteome. CONCLUSION: The study highlights distinct tissue compartmentalization of sulfur-related metabolites in normal mice, extensive metabolome, proteome and sphingolipidome disruptions in I278T mice, and the efficacy of MRD to alleviate some of the HCU-related biochemical abnormalities.

Quantification of Cinpanemab (BIIB054) Binding to α- Synuclein in Cerebrospinal Fluid of Phase 1 Single Ascending Dose Samples.

Through its pathological and genetic association to Parkinson's Disease (PD), α-synuclein (α-syn) remains a favorable therapeutic target that is being investigated using various modalities, including many passive immunotherapy approaches clinically targeting different forms of α-syn and epitopes. Whereas published studies from some immunotherapy trials have demonstrated engagement in plasma, none have shown direct drug-antigen interactions in the disease-relevant compartment, the central nervous system (CNS). Cinpanemab (BIIB054) selectively targets pathological aggregated α-syn with low affinity binding to monomeric forms. The avidity-driven binding, low drug concentration, and the very low α-syn levels plus its heterogeneous nature in cerebrospinal fluid (CSF) made it not possible to measure drug-target interactions by conventional assays. Here we overcame these challenges by using zero-length crosslinking to stabilize the BIIB054-α-syn complexes and then quantified the crosslinked complexes using a Meso Scale Discovery (MSD) electrochemiluminescence assay. CSF samples from healthy volunteers (HV, n=46) and individuals with PD (PD, n=18) from study 228HV101 (Phase I clinical trial of BIIB054), demonstrated dose- and time- dependent binding of cinpanemab to α-syn with measurable complexes detected at doses {greater than or equal to}15 mg/kg. Complex formation displayed a direct positive correlation to drug concentration (Spearman rank correlation = 0.8295 (HV), 0.8032 (PD) p < 0.0001 (HV, PD)). The observed binding of cinpanemab to α-syn in CSF is consistent with its low intrinsic affinity for α-syn monomer and provides evidence that the drug is behaving with expected binding dynamics in the central nervous system compartment. Significance Statement A zero-length cross-linking method with MSD detection was developed to enable quantification of cinpanemab-α-syn complexes in Phase 1 clinical CSF samples by preventing signal loss caused by their rapid dissociation. Observed dose- and time-dependent binding were consistent with cinpanemab's affinity for α-syn and provided confidence that the drug had engaged its target at the desired site of action. This is the first demonstration of α-syn binding by an antibody in clinical samples from the CNS.

The Arcus Experience: Bridging the Data Science Gap for Nurse Researchers.

BACKGROUND: For years, nurse researchers have been called upon to engage with "big data" in the electronic health record (EHR) by leading studies focusing on nurse-centric patient outcomes and providing clinical analysis of potential outcome indicators. However, the current gap in nurses' data science education and training poses a significant barrier. OBJECTIVES: We aimed to evaluate the viability of conducting nurse-led, big-data research projects within a custom-designed computational laboratory and examine the support required by a team of researchers with little to no big-data experience. METHODS: Four nurse-led research teams developed a research question reliant on existing EHR data. Each team was given its own virtual computational laboratory populated with raw data. A data science education team provided instruction in coding languages-primarily structured query language and R-and data science techniques to organize and analyze the data. RESULTS: Three research teams have completed studies, resulting in one manuscript currently undergoing peer review and two manuscripts in progress. The final team is performing data analysis. Five barriers and five facilitators to big-data projects were identified. DISCUSSION: As the data science learning curve is steep, organizations need to help bridge the gap between what is currently taught in doctoral nursing programs and what is required of clinical nurse researchers to successfully engage in big-data methods. In addition, clinical nurse researchers require protected research time and a data science infrastructure that supports novice efforts with education, mentorship, and computational laboratory resources.

Aligning goals with care: Advance directives in older adults with implantable cardioverter-defibrillators.

BACKGROUND: Patients ≥80 with implantable cardioverter-defibrillators (ICDs) have high rates of hospitalization and mortality, yet few have documented advance directives. We sought to determine the prevalence of advance directives in adults ≥80 years with ICDs, focusing on those with frailty and cognitive impairment. METHODS: Prospective cohort study (July 2016-May 2019) in an electrophysiology clinic. Presence of advance directives (health care proxies [HCP] and living wills [LW], or medical orders for life-sustaining treatment [MOLST]) was determined by medical record review. Frailty and cognitive impairment were screened using 4-m gait speed and Mini-Cog. RESULTS: 77 Veterans were evaluated. Mean age 84 years, 100% male, 70% frail. Overall, 52 (68%) had an HCP and 37 (48%) had a LW/MOLST. Of 67 with cognitive testing, 36% were impaired. HCP documentation was similar among frail and non-frail (69% vs. 65%). LW/MOLST was more prevalent among frail versus non-frail (52% vs. 39%). There was no difference in HCP documentation by cognitive status (67%). A LW/MOLST was more frequent for cognitively impaired versus non-impaired (50% vs. 42%). Among 19 Veterans who were frail and cognitively impaired, 14 (74%) had an HCP and 11 (58%) had a LW/MOLST. CONCLUSIONS: Most Veterans had a documented advance directive, but a significant minority did not. Simple frailty and cognitive screening tools can rapidly identify patients for whom discussion of advance directives is especially important.

Law Enforcement Officers Have an Increased Prevalence of Subclinical Cardiovascular Disease That Is Not Explained by Traditional Risk Factors.

OBJECTIVES: The aim of the study is to determine if law enforcement officers develop subclinical atherosclerotic cardiovascular disease (ASCVD) earlier than nonofficers and, if so, the extent to which conventional risk factors explain this difference. Methods: Estimated pulse wave velocity (ePWV) was the marker of subclinical ASCVD. EPWV, ASCVD risk factors, metabolic syndrome (MetS), and 10-year risk for ASCVD were compared among 408 law enforcement officers and a civilian cohort. Results: EPWV, 10-year ASCVD risk, and MetS prevalence increased significantly with age. All but the officers age 55 and older had higher ePWV cohort than the civilian cohort ( P < 0.001). Ten-year ASCVD risk explained the most variability of ePWV ( R2 = 0.49, P < 0.001). Conclusions: Officers develop subclinical ASCVD earlier than nonofficers. Conventional ASCVD risk factors only explain about half of this increase. Occupational factors may play a role in contributing to this increased ASCVD risk.

Psychological correlates of physical activity among adults living in rural and urban settings.

Middle-aged and older adults living in rural settings have been consistently less likely to report regular physical activity (PA) than those living in urban settings. While past literature has identified sociodemographic and environmental correlates of PA that may contribute to these differences, consideration of psychological correlates has been limited. A total of 95 rural and urban adults ≥50 years old provided self-reported sociodemographic information, PA level, and psychological correlates of PA including measures assessing motivation, self-efficacy, social support, and attitudes related to PA. The average participant age was 68.6 years, and most were female (62.1%) and married (70.5%). While PA level did not differ significantly between the rural and urban groups, different psychological correlates contributed significantly to separate rural and urban linear regression models considering PA status. Among rural adults, more positive attitudes toward PA, and greater PA self-efficacy and social support were associated with greater amounts of PA while for urban adults, no psychological correlates were significantly associated with PA. Psychosocial factors may be key considerations in developing more effective PA interventions in middle-aged and older adults living in rural areas.

Virtual Reality Adaptive Training for Personalized Stress Inoculation.

OBJECTIVE: To evaluate a personalized adaptive training program designed for stress prevention using graduated stress exposure. BACKGROUND: Astronauts in the high-risk space mission environment are prone to performance-impairing stress responses, making preemptive stress inoculation essential for their training. METHODS: This work developed an adaptive virtual reality-based system that adjusts environmental stressors based on real-time stress indicators to optimize training stress levels. Sixty-five healthy subjects underwent task training in one of three groups: skill-only (no stressors), fixed-graduated (prescheduled stressor changes), and adaptive. Psychological (subjective stress, task engagement, distress, worry, anxiety, and workload) and physiological (heart rate, heart rate variability, blood pressure, and electrodermal activity) responses were measured. RESULTS: The adaptive condition showed a significant decrease in heart rate and a decreasing trend in heart rate variability ratio, with no changes in the other training conditions. Distress showed a decreasing trend for the graduated and adaptive conditions. Task engagement showed a significant increase for adaptive and a significant decrease for the graduated condition. All training conditions showed a significant decrease in worry and anxiety and a significant increase in the other heart rate variability metrics. CONCLUSION: Although all training conditions mitigated some stress, the preponderance of trial effects for the adaptive condition supports that it is more successful at decreasing stress. APPLICATION: The integration of real-time personalized stress exposure within a VR-based training program not only prepares individuals for high-stress situations by preemptively mitigating stress but also customizes stressor levels to the crew member's current state, potentially enhancing resilience to future stressors.