Capturing the catalytic intermediates of parkin ubiquitination.

Parkin is an E3 ubiquitin ligase implicated in early-onset forms of Parkinson's disease. It catalyzes a transthiolation reaction by accepting ubiquitin (Ub) from an E2 conjugating enzyme, forming a short-lived thioester intermediate, and transfers Ub to mitochondrial membrane substrates to signal mitophagy. A major impediment to the development of Parkinsonism therapeutics is the lack of structural and mechanistic detail for the essential, short-lived transthiolation intermediate. It is not known how Ub is recognized by the catalytic Rcat domain in parkin that enables Ub transfer from an E2~Ub conjugate to the catalytic site and the structure of the transthiolation complex is undetermined. Here, we capture the catalytic intermediate for the Rcat domain of parkin in complex with ubiquitin (Rcat-Ub) and determine its structure using NMR-based chemical shift perturbation experiments. We show that a previously unidentified α-helical region near the Rcat domain is unmasked as a recognition motif for Ub and guides the C-terminus of Ub toward the parkin catalytic site. Further, we apply a combination of guided AlphaFold modeling, chemical cross-linking, and single turnover assays to establish and validate a model of full-length parkin in complex with UbcH7, its donor Ub, and phosphoubiquitin, trapped in the process of transthiolation. Identification of this catalytic intermediate and orientation of Ub with respect to the Rcat domain provides important structural insights into Ub transfer by this E3 ligase and explains how the previously enigmatic Parkinson's pathogenic mutation T415N alters parkin activity.

Epidemiology and outcomes of primary sclerosing cholangitis: an Australian multicentre retrospective cohort study.

BACKGROUND AND AIMS: Little is known regarding the epidemiology and outcomes of patients with primary sclerosing cholangitis (PSC) in Australia. We, therefore, evaluated the epidemiology and clinical outcomes of PSC in a large cohort of Australian patients and compared these to the general population. METHODS: We conducted a multicentre, retrospective cohort study of PSC patients at nine tertiary liver centers across three Australian states, including two liver transplant centers. RESULTS: A total of 413 PSC patients with 3,285 person-years of follow-up were included. Three hundred and seventy-one (90%) patients had large duct PSC and 294 (71%) had associated inflammatory bowel disease. A total of 168 (41%) patients developed cirrhosis (including 34 at the time of PSC diagnosis) after a median of 15.8 (95% CI 12.4, NA) years. The composite endpoint of death or liver transplantation occurred in 49 (12%) and 78 (19%) patients, respectively, with a median transplant-free survival of 13.4 (95% CI 12.2-15) years. Compared to the general population, PSC accounted for a 240-fold increased risk of development of cholangiocarcinoma (CCA) and CCA-related death. CCA risk was increased with older age of PSC diagnosis, presence of dominant stricture and colectomy. Compared to same-aged counterparts in the general population, PSC patients who were diagnosed at an older age or with longer disease duration had reduced relative survival. CONCLUSION: In this large retrospective cohort study of PSC patients in Australia, increased age and time from diagnosis was associated with increased mortality and morbidity particularly from CCA and development of cirrhosis, necessitating need for liver transplant.

The Importance of Understanding Individual Differences of Emotion Regulation Abilities in 22q11.2 Deletion Syndrome.

Chromosome 22q11.2 deletion syndrome (22q11DS) is characterised by a complex behavioural phenotype including anxiety, attention-deficit/hyperactivity disorder and psychosis. In the current study, we aimed at improving our understanding of the heterogeneity of behavioural characteristics in a group of 129 young people (aged 4-22) with a confirmed 22q11.2 microdeletion and 116 age and gender matched typically developing controls. Half the participants with 22q11DS had behaviour characterised by emotion dysregulation. A cluster analyses, of the participants with 22q11DS, revealed four groups characterised by intact emotion regulation; predominantly internalizing problems; both internalizing and externalizing problems; and predominantly externalizing difficulties. Importantly, it was found that young people with 22q11DS whose emotion dysregulation was characterised by externalizing problems had the poorest levels of functioning. As our understanding of 22q11DS improves, it is becoming increasingly clear that we need a better understanding of how individual differences and psychosocial factors contribute to, and interact with one another, to result in the observable individual differences in the 22q11DS behavioural phenotype.

Assessing awareness on biodiversity conservation among Nigerians: the Aichi Biodiversity Target 1.

The adoption of the Aichi Biodiversity Targets (ABTs) was supposed to increase conservation awareness in different countries and regions of the world. However, there seems to be a limited understanding of the importance of ecosystem services, offered by biological diversity. Thus, the continued decline in biodiversity, especially in developing countries. This study appraised the level of success of the first target of Nigeria's National Biodiversity Strategy and Action Plan (NBSAP), which is hinged on the first ABT. In a national survey, data were obtained from a total of 1,124 respondents (839 professionals and 285 non-professionals), using a structured questionnaire. Information on the respondents' knowledge of biodiversity conservation and the associated ecosystem services, were elicited. Most of the non-professionals had a low level of understanding of biodiversity concepts (4.9 ± 1.7 to 20.5 ± 3.4%), while there was a moderate level of understanding among the professionals (48.0 ± 8.6 to 88.8 ± 3.4%). Awareness of the NBSAP was low for both groups (43.8 ± 7.2% professionals and 12.1 ± 3.7% non-professionals). The study concludes that there is a need to step up campaigns on biodiversity conservation in Nigeria and promote visits to natural sites. Youth engagement through the employment of graduates of biology-related disciplines, to educate the public on biodiversity conservation and the action plan, could also be a strong determinant to the success of the NBSAP targets.

Irreversible Electroporation For Hepatocellular Carcinoma: Longer-Term Outcomes At A Single Centre.

BACKGROUND AND AIMS: Irreversible electroporation (IRE) is a non-thermal ablation technique for unresectable hepatocellular carcinoma (HCC) not amenable to standard thermal ablation. The aim of this study was to report our longer-term outcomes using this treatment modality. METHOD: We identified all patients at our institution who underwent IRE for HCC between December 2008 and October 2019 as recommended after multi-disciplinary team review. Demographic, clinical, tumour response and survival data up until 1 March, 2020 were analysed. The primary outcome was local recurrence-free survival (LRFS) in patients who had a complete response (CR). Secondary outcomes included CR rates, procedure-related complications and the incidence of death or liver transplantation. RESULTS: A total of 23 patients (78% males, median age 65.2 years) received IRE therapy to 33 HCC lesions during the study period with the median tumour size being 2.0 cm (range 1.0-5.0 cm). Twenty-nine (87.9%) lesions were successfully ablated after one (n = 26) or two (n = 3) procedures. The median follow-up time for these lesions was 20.4 months. The median overall LRFS was 34.5 (95% CI 24.8 -) months with a 6- and 12-month LRFS of 87.9% (95% CI 75.8-100) and 83.6% (95% CI 70.2-99.7), respectively. Tumours < 2 cm had a 12-month LRFS of 100% (95% CI 100-100). CONCLUSION: IRE appears to be an efficacious local ablative method for early stage HCC not amenable to standard ablative techniques, with very good CR rates and longer-term LRFS, particularly for smaller lesions. Further studies comparing this technique to more widely accepted ablative methods such as radiofrequency and microwave ablation are warranted.

A systematic review and meta-analysis of dementia prevalence in seven developing countries: A STRiDE project.

The STRiDE project sets out to support the development of effective dementia policy in middle-income countries (Brazil, India, Indonesia, Jamaica, Kenya, Mexico, and South Africa). As part of this it will generate new data about the prevalence of dementia for a subset of these countries. This study aims to identify the current estimates of dementia prevalence in these countries and where the gaps lie in the current literature. A systematic review was completed on 30th April 2019 across electronic databases, identifying dementia prevalence literature originating from any of the seven countries. Four hundred and twenty-nine records were identified following de-duplication; 28 studies met the inclusion criteria and were included in the systematic review. Pooled estimates of dementia prevalence ranged from 2% to 9% based on DSM-IV criteria; these figures were generally higher in studies using other diagnostic criteria (e.g. the 10/66 algorithm). Available prevalence data varied between countries. Only Brazil, Mexico and India had data derived from studies judged as having a low risk of bias. Irrespective of country, studies often were not explicit in detailing the representativeness of their sample, or whether there was non-response bias. Further transparent and externally valid dementia prevalence research is needed across the STRiDE countries.

Implementation and dissemination of an African American popular opinion model to improve lupus awareness: an academic-community partnership.

OBJECTIVE: Lupus is a chronic, autoimmune disease that disproportionately affects African Americans. We adapted the Centers for Disease Control and Prevention's Popular Opinion Leader model to implement an intervention tailored for African American individuals that leverages an academic-community partnership and community-based social networks to disseminate culturally appropriate lupus education. METHODS: Academic rheumatologists, social scientists, and researchers in Boston, MA and Chicago, IL partnered with local lupus support groups, community organizations, and churches in neighborhoods with higher proportions of African Americans to develop curriculum and recruit community leaders with and without lupus (Popular Opinion Leaders; POLs). POLs attended four training sessions focused on lupus education, strategies to educate others, and a review of research methods. POLs disseminated information through their social networks and recorded their impact, which was mapped using a geographic information system framework. RESULTS: We trained 18 POLs in greater Boston and 19 in greater Chicago: 97% were African American, 97% were female; and the mean age was 57 years. Fifty-nine percent of Boston POLs and 68% of Chicago POLs had lupus. POLs at both sites engaged members of their social networks and communities in conversations about lupus, health disparities, and the importance of care. Boston POLs documented 97 encounters with 547 community members reached. Chicago POLs documented 124 encounters with 4083 community members reached. CONCLUSIONS: An adapted, community-based POL model can be used to disseminate lupus education and increase awareness in African American communities. Further research is needed to determine the degree to which this may begin to reduce disparities in access to care and outcomes.

Synergistic recruitment of UbcH7~Ub and phosphorylated Ubl domain triggers parkin activation.

The E3 ligase parkin ubiquitinates outer mitochondrial membrane proteins during oxidative stress and is linked to early-onset Parkinson's disease. Parkin is autoinhibited but is activated by the kinase PINK1 that phosphorylates ubiquitin leading to parkin recruitment, and stimulates phosphorylation of parkin's N-terminal ubiquitin-like (pUbl) domain. How these events alter the structure of parkin to allow recruitment of an E2~Ub conjugate and enhanced ubiquitination is an unresolved question. We present a model of an E2~Ub conjugate bound to the phospho-ubiquitin-loaded C-terminus of parkin, derived from NMR chemical shift perturbation experiments. We show the UbcH7~Ub conjugate binds in the open state whereby conjugated ubiquitin binds to the RING1/IBR interface. Further, NMR and mass spectrometry experiments indicate the RING0/RING2 interface is re-modelled, remote from the E2 binding site, and this alters the reactivity of the RING2(Rcat) catalytic cysteine, needed for ubiquitin transfer. Our experiments provide evidence that parkin phosphorylation and E2~Ub recruitment act synergistically to enhance a weak interaction of the pUbl domain with the RING0 domain and rearrange the location of the RING2(Rcat) domain to drive parkin activity.

Does AMH relate to timing of menopause? Results of an Individual Patient Data meta- analysis.

CONTEXT: Anti-Müllerian hormone based (AMH) age at menopause predictions remain cumbersome due to predictive inaccuracy. OBJECTIVE: To perform an Individual Patient Data (IPD) meta-analysis, regarding AMH based menopause prediction. DATA SOURCES: A systematic literature search was performed using PubMed, Embase and Cochrane databases. STUDY SELECTION: Prospective cohort studies regarding menopause prediction using serum AMH levels were selected by consensus discussion. DATA SELECTION: Individual cases were included if experiencing a regular cycle at baseline. Exclusion criteria were hormone use and gynecological surgery. DATA SYNTHESIS: 2596 women were included, 1077 experienced menopause. A multivariable Cox regression analysis assessed time to menopause (TTM) using age and AMH. AMH predicted TTM, however, added value on top of age was poor (age alone C-statistic 84%; age + AMH HR 0.66 95% CI 0.61-0.71, C-statistic 86%). Moreover, the capacity of AMH to predict early (≤45 years) and late menopause (≥55 years) was assessed. An added effect of AMH was demonstrated for early menopause (age alone C-statistic 52%; age + AMH HR 0.33, 95% CI 0.24-0.45, C-statistic 80%). A Weibull regression model calculating individual age at menopause revealed that predictive inaccuracy remained present and increased with decreasing age at menopause. Lastly, a check of non-proportionality of the predictive effect of AMH demonstrated a reduced predictive effect with increasing age. CONCLUSION: AMH was a significant predictor of TTM and especially of time to early menopause. However, individual predictions of age at menopause demonstrated a limited precision, particularly when concerning early age at menopause, making clinical application troublesome.

Erythropoietin Upregulates Brain Hemoglobin Expression and Supports Neuronal Mitochondrial Activity.

Multiple sclerosis (MS) is a neuro-inflammatory and demyelinating disease. Downregulation of neuronal mitochondrial gene expression and activity have been reported in several studies of MS. We have previously shown that hemoglobin-ß (Hbb) signals to the nucleus of neurons and upregulates H3K4me3, a histone mark involved in regulating cellular metabolism and differentiation. The present study was undertaken to evaluate the effect of erythropoietin (EPO) on the upregulation of hemoglobin and mitochondrial-associated neuroprotection. We found that administering EPO (5000 IU/kg intraperitoneally) to mice upregulated brain Hbb expression, levels of H3K4me3, expression of mitochondrial complex III, complex V, and mitochondrial respiration. We also found that the neuronal mitochondrial metabolite N-acetylaspartate (NAA), a marker of neuronal mitochondrial activity, was increased with EPO treatment. Further, we measured the effects of EPO on preventing mitochondrial deficits in the cuprizone toxic demyelinating mouse model of MS. We found that EPO prevented cuprizone-mediated decreases in Hbb, complex III, and NAA. Our data suggest that EPO mediated regulation of Hbb supports neuronal energetics and may provide neuroprotection in MS and other neurodegenerative diseases where a dysfunction of mitochondria contributes to disease.

Liquid crystal elastomer foams with elastic properties specifically engineered as biodegradable brain tissue scaffolds.

Tissue regeneration requires 3-dimensional (3D) smart materials as scaffolds to promote transport of nutrients. To mimic mechanical properties of extracellular matrices, biocompatible polymers have been widely studied and a diverse range of 3D scaffolds have been produced. We propose the use of responsive polymeric materials to create dynamic substrates for cell culture, which goes beyond designing only a physical static 3D scaffold. Here, we demonstrated that lactone- and lactide-based star block-copolymers (SBCs), where a liquid crystal (LC) moiety has been attached as a side-group, can be crosslinked to obtain Liquid Crystal Elastomers (LCEs) with a porous architecture using a salt-leaching method to promote cell infiltration. The obtained SmA LCE-based fully interconnected-porous foams exhibit a Young modulus of 0.23 ± 0.07 MPa and a biodegradability rate of around 20% after 15 weeks both of which are optimized to mimic native environments. We present cell culture results showing growth and proliferation of neurons on the scaffold after four weeks. This research provides a new platform to analyse LCE scaffold-cell interactions where the presence of liquid crystal moieties promotes cell alignment paving the way for a stimulated brain-like tissue.

Dysregulation of methionine metabolism in multiple sclerosis.

We report a significant reduction in plasma methionine concentrations in relapse remitting multiple sclerosis (MS) patients compared to controls. In vivo studies demonstrate that changes in peripheral methionine levels in mice can regulate histone H3 methylation and expression of DNA methyltransferase 3A (DNMT3A) centrally, in the cerebral cortex. Therefore, we propose that decreases in circulating methionine represent one of the earliest manifestations of dysregulated methionine metabolism in MS with potential impacts on both histone H3 and DNA methylation in the central nervous system.

Improving the magnetoelectric performance of Metglas/PZT laminates by annealing in a magnetic field.

A comprehensive investigation of magnetostriction optimization in Metglas 2605SA1 ribbons is performed to enhance magnetoelectric performance. We explore a range of annealing conditions to relieve remnant stress and align the magnetic domains in the Metglas, while minimizing unwanted crystallization. The magnetostriction coefficient, magnetoelectric coefficient, and magnetic domain alignment are correlated to optimize magnetoelectric performance. We report on direct magnetostriction observed by in-plane Doppler vibrometer and domain imagining using scanning electron microscopy with polarization analysis for a range of annealing conditions. We find that annealing in an oxygen-free environment at 400 °C for 30 min yields an optimal magnetoelectric coefficient, magnetostriction and magnetostriction coefficient. The optimized ribbons had a magnetostriction of 50.6 ± 0.2 µm m-1 and magnetoelectric coefficient of 79.3 ± 1.5 µm m-1 mT-1. The optimized Metglas 2605SA1 ribbons and PZT-5A (d31 mode) sensor achieves a magnetic noise floor of approximately 600 pT Hz-1/2 at 100 Hz and a magnetoelectric coefficient of 6.1 ± 0.03 MV m-1 T-1.

Radiocarbon constraints on the glacial ocean circulation and its impact on atmospheric CO2.

While the ocean's large-scale overturning circulation is thought to have been significantly different under the climatic conditions of the Last Glacial Maximum (LGM), the exact nature of the glacial circulation and its implications for global carbon cycling continue to be debated. Here we use a global array of ocean-atmosphere radiocarbon disequilibrium estimates to demonstrate a ∼689±53 14C-yr increase in the average residence time of carbon in the deep ocean at the LGM. A predominantly southern-sourced abyssal overturning limb that was more isolated from its shallower northern counterparts is interpreted to have extended from the Southern Ocean, producing a widespread radiocarbon age maximum at mid-depths and depriving the deep ocean of a fast escape route for accumulating respired carbon. While the exact magnitude of the resulting carbon cycle impacts remains to be confirmed, the radiocarbon data suggest an increase in the efficiency of the biological carbon pump that could have accounted for as much as half of the glacial-interglacial CO2 change.