Cost-effectiveness of acceptance and commitment therapy for people living with motor neuron disease, and their health-related quality of life.

BACKGROUND: Given the degenerative nature of the condition, people living with motor neuron disease (MND) experience high levels of psychological distress. The purpose of this research was to investigate the cost-effectiveness of acceptance and commitment therapy (ACT), adapted for the specific needs of this population, for improving quality of life. METHODS: A trial-based cost-utility analysis over a 9-month period was conducted comparing ACT plus usual care (n = 97) versus usual care alone (n = 94) from the perspective of the National Health Service. In the primary analysis, quality-adjusted life years (QALYs) were computed using health utilities generated from the EQ-5D-5L questionnaire. Sensitivity analyses and subgroup analyses were also carried out. RESULTS: Difference in costs was statistically significant between the two arms, driven mainly by the intervention costs. Effects measured by EQ-5D-5L were not statistically significantly different between the two arms. The incremental cost-effectiveness was above the £20,000 to £30,000 per QALY gained threshold used in the UK. However, the difference in effects was statistically significant when measured by the McGill Quality of Life-Revised (MQOL-R) questionnaire. The intervention was cost-effective in a subgroup experiencing medium deterioration in motor neuron symptoms. CONCLUSIONS: Despite the intervention being cost-ineffective in the primary analysis, the significant difference in the effects measured by MQOL-R, the low costs of the intervention, the results in the subgroup analysis, and the fact that ACT was shown to improve the quality of life for people living with MND, suggest that ACT could be incorporated into MND clinical services.

Formation of a conceptual framework during the development of a patient-reported outcome measure for early gastrointestinal recovery: phase I of the PRO-diGi study.

AIM: Patients admitted to hospital for abdominal surgery often experience gastrointestinal dysfunction. Many studies have reported outcomes following gastrointestinal dysfunction, yet there is no unified definition of recovery or a validated patient-reported outcome measure (PROM). The first stage of PROM development requires formation of a conceptual framework to identify key themes to patients. The aim of this study was to utilize semistructured interviews to identify core themes and concepts relevant to patients to facilitate development of a conceptual framework. METHOD: Adult patients admitted to hospital for major gastrointestinal, urological or gynaecological surgery, in an emergency or elective setting, were eligible to participate. Patients treated nonoperatively for small bowel obstruction were also eligible. Interviews were conducted by telephone, audio-recorded, transcribed, coded and analysed using NVivo software by two researchers and reviewed by lay members of the steering group. Interviews continued until data saturation was reached. Ethical approval was gained prior to interviews (21/WA/0231). RESULTS: Twenty nine interviews were completed (17 men, median age 64 years) across three specialties (20 gastrointestinal, six gynaecological, three urological). Two overarching themes of 'general recovery' and 'gastrointestinal symptoms' were identified. General recovery included three themes: 'life impact', 'mental impact', including anxiety, and 'physical impact', including fatigue. Gastrointestinal symptoms included three themes: 'abdominal symptoms' such as pain, 'diet and appetite' and 'expulsory function', such as stool frequency. A total of 18 gastrointestinal symptoms were identified during patient recovery-many of which lasted several weeks following discharge. CONCLUSION: This study reports a range of gastrointestinal and nongastrointestinal symptoms experienced by patients during early gastrointestinal recovery. Identified symptoms have been synthesized into a conceptual framework to enable development of a definitive PROM for early gastrointestinal recovery.

A randomised controlled trial of acceptance and commitment therapy plus usual care compared to usual care alone for improving psychological health in people with motor neuron disease (COMMEND): study protocol.

BACKGROUND: Motor neuron disease (MND) is a rapidly progressive, fatal neurodegenerative disease that predominantly affects motor neurons from the motor cortex to the spinal cord and causes progressive wasting and weakening of bulbar, limb, abdominal and thoracic muscles. Prognosis is poor and median survival is 2-3 years following symptom onset. Psychological distress is relatively common in people living with MND. However, formal psychotherapy is not routinely part of standard care within MND Care Centres/clinics in the UK, and clear evidence-based guidance on improving the psychological health of people living with MND is lacking. Previous research suggests that Acceptance and Commitment Therapy (ACT) may be particularly suitable for people living with MND and may help improve their psychological health. AIMS: To assess the clinical and cost-effectiveness of ACT modified for MND plus usual multidisciplinary care (UC) in comparison to UC alone for improving psychological health in people living with MND. METHODS: The COMMEND trial is a multi-centre, assessor-blind, parallel, two-arm RCT with a 10-month internal pilot phase. 188 individuals aged ≥ 18 years with a diagnosis of definite, laboratory-supported probable, clinically probable, or possible familial or sporadic amyotrophic lateral sclerosis, and additionally the progressive muscular atrophy and primary lateral sclerosis variants, will be recruited from approximately 14 UK-based MND Care Centres/clinics and via self-referral. Participants will be randomly allocated to receive up to eight 1:1 sessions of ACT plus UC or UC alone by an online randomisation system. Participants will complete outcome measures at baseline and at 6- and 9-months post-randomisation. The primary outcome will be quality of life at six months. Secondary outcomes will include depression, anxiety, psychological flexibility, health-related quality of life, adverse events, ALS functioning, survival at nine months, satisfaction with therapy, resource use and quality-adjusted life years. Primary analyses will be by intention to treat and data will be analysed using multi-level modelling. DISCUSSION: This trial will provide definitive evidence on the clinical and cost-effectiveness of ACT plus UC in comparison to UC alone for improving psychological health in people living with MND. TRIAL REGISTRATION: ISRCTN Registry, ISRCTN12655391. Registered 17 July 2017, https://www.isrctn.com/ISRCTN12655391 . PROTOCOL VERSION: 3.1 (10/06/2020).

The Journeying through Dementia psychosocial intervention versus usual care study: a single-blind, parallel group, phase 3 trial.

BACKGROUND: There is an urgent clinical need for evidence-based psychosocial interventions for people with mild dementia. We aimed to determine the clinical benefits and cost-effectiveness of Journeying through Dementia (JtD), an intervention designed to promote wellbeing and independence in people with mild dementia. METHODS: We did a single-blind, parallel group, individually randomised, phase 3 trial at 13 National Health Service sites across England. People with mild dementia (Mini-Mental State Examination score of ≥18) who lived in the community were eligible for inclusion. Patients were centrally randomly assigned (1:1) to receive the JtD intervention plus standard care (JtD group) or standard care only (standard care group). Randomisation was stratified by study site. The JtD intervention included 12 group and four one-to-one sessions, delivered in the community at each site. The primary endpoint was Dementia Related Quality of Life (DEMQOL) 8 months after randomisation, assessed according to the intention-to-treat principle. Only outcome assessors were masked to group assignment. A cost-effectiveness analysis reported cost per quality-adjusted life-year (QALY) from a UK NHS and social care perspective. The study is registered with ISRCTN, ISRCTN17993825. FINDINGS: Between Nov 30, 2016, and Aug 31, 2018, 1183 patients were screened for inclusion, of whom 480 (41%) participants were randomly assigned: 241 (50%) to the JtD group and 239 (50%) to the standard care group. Intervention adherence was very good: 165 (68%) of 241 participants in the JtD group attended at least ten of the 16 sessions. Mean DEMQOL scores at 8 months were 93·3 (SD 13·0) for the JtD group and 91·9 (SD 14·6) for the control group. Difference in means was 0·9 (95% CI -1·2 to 3·0; p=0·38) after adjustment for covariates, lower than that identified as clinically meaningful. Incremental cost per QALY ranged from £88 000 to -£205 000, suggesting that JtD was not cost-effective. Unrelated serious adverse events were reported by 40 (17%) patients in the JtD group and 35 (15%) patients in the standard care group. INTERPRETATION: In common with other studies, the JtD intervention was not proven effective. However, this complex trial successfully recruited and retained people with dementia without necessarily involving carers. Additionally, people with dementia were actively involved as participants and study advisers throughout. More research into methods of measuring small, meaningful changes in this population is needed. Questions remain regarding how services can match the complex, diverse, and individual needs of people with mild dementia, and how interventions to meet such needs can be delivered at scale. FUNDING: UK National Institute of Health Research Health Technology Assessment Programme.

An intervention to promote self-management, independence and self-efficacy in people with early-stage dementia: the Journeying through Dementia RCT.

BACKGROUND: There are few effective interventions for dementia. AIM: To determine the clinical effectiveness and cost-effectiveness of an intervention to promote self-management, independence and self-efficacy in people with early-stage dementia. OBJECTIVES: To undertake a randomised controlled trial of the Journeying through Dementia intervention compared with usual care, conduct an internal pilot testing feasibility, assess intervention delivery fidelity and undertake a qualitative exploration of participants' experiences. DESIGN: A pragmatic two-arm individually randomised trial analysed by intention to treat. PARTICIPANTS: A total of 480 people diagnosed with mild dementia, with capacity to make informed decisions, living in the community and not participating in other studies, and 350 supporters whom they identified, from 13 locations in England, took part. INTERVENTION: Those randomised to the Journeying through Dementia intervention (n = 241) were invited to take part in 12 weekly facilitated groups and four one-to-one sessions delivered in the community by secondary care staff, in addition to their usual care. The control group (n = 239) received usual care. Usual care included drug treatment, needs assessment and referral to appropriate services. Usual care at each site was recorded. MAIN OUTCOME MEASURES: The primary outcome was Dementia-Related Quality of Life score at 8 months post randomisation, with higher scores representing higher quality of life. Secondary outcomes included resource use, psychological well-being, self-management, instrumental activities of daily living and health-related quality of life. RANDOMISATION AND BLINDING: Participants were randomised in a 1 : 1 ratio. Staff conducting outcome assessments were blinded. DATA SOURCES: Outcome measures were administered in participants' homes at baseline and at 8 and 12 months post randomisation. Interviews were conducted with participants, participating carers and interventionalists. RESULTS: The mean Dementia-Related Quality of Life score at 8 months was 93.3 (standard deviation 13.0) in the intervention arm (n = 191) and 91.9 (standard deviation 14.6) in the control arm (n = 197), with a difference in means of 0.9 (95% confidence interval -1.2 to 3.0; p = 0.380) after adjustment for covariates. This effect size (0.9) was less than the 4 points defined as clinically meaningful. For other outcomes, a difference was found only for Diener's Flourishing Scale (adjusted mean difference 1.2, 95% confidence interval 0.1 to 2.3), in favour of the intervention (i.e. in a positive direction). The Journeying through Dementia intervention cost £608 more than usual care (95% confidence interval £105 to £1179) and had negligible difference in quality-adjusted life-years (-0.003, 95% confidence interval -0.044 to 0.038). Therefore, the Journeying through Dementia intervention had a mean incremental cost per quality-adjusted life-year of -£202,857 (95% confidence interval -£534,733 to £483,739); however, there is considerable uncertainty around this. Assessed fidelity was good. Interviewed participants described receiving some benefit and a minority benefited greatly. However, negative aspects were also raised by a minority. Seventeen per cent of participants in the intervention arm and 15% of participants in the control arm experienced at least one serious adverse event. None of the serious adverse events were classified as related to the intervention. LIMITATIONS: Study limitations include recruitment of an active population, delivery challenges and limitations of existing outcome measures. CONCLUSIONS: The Journeying through Dementia programme is not clinically effective, is unlikely to be cost-effective and cannot be recommended in its existing format. FUTURE WORK: Research should focus on the creation of new outcome measures to assess well-being in dementia and on using elements of the intervention, such as enabling enactment in the community. TRIAL REGISTRATION: This trial is registered as ISRCTN17993825. FUNDING: This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 24. See the NIHR Journals Library website for further project information.

There are few services proven effective for people with mild dementia. We therefore explored the potential benefit of a programme called Journeying through Dementia. The content, devised in partnership with people living with dementia, aims to help affected individuals to live well and participate in life. The programme involves meeting in groups of about eight every week for 12 weeks. Each person also has four face-to-face meetings with a staff member. Carers are invited to 3 of the 12 group meetings to all individual meetings if the participant wanted this involvement. A total of 480 people with dementia and 350 carers from 13 locations in England took part. Just over half of the participants were randomly allocated to the new programme, whereas the others were not. This allowed us to compare the groups. We were interested in whether or not attending the Journeying through Dementia programme improved participants' quality of life. The results showed that it did not. We also measured participants' mood, self-management skills, positive attitudes and ability with daily living skills. Only one measure of positive psychology suggested even a small benefit. There was no difference between groups in the remaining measures. Although some individual participants described being more confident, enjoying social contact, trying new activities, feeling valued and having increased independence, overall, the programme is unlikely to be worth implementing. Certain aspects of the programme are worth implementing.

Life-threatening viral disease in a novel form of autosomal recessive IFNAR2 deficiency in the Arctic.

Type I interferons (IFN-I) play a critical role in human antiviral immunity, as demonstrated by the exceptionally rare deleterious variants of IFNAR1 or IFNAR2. We investigated five children from Greenland, Canada, and Alaska presenting with viral diseases, including life-threatening COVID-19 or influenza, in addition to meningoencephalitis and/or hemophagocytic lymphohistiocytosis following live-attenuated viral vaccination. The affected individuals bore the same homozygous IFNAR2 c.157T>C, p.Ser53Pro missense variant. Although absent from reference databases, p.Ser53Pro occurred with a minor allele frequency of 0.034 in their Inuit ancestry. The serine to proline substitution prevented cell surface expression of IFNAR2 protein, small amounts of which persisted intracellularly in an aberrantly glycosylated state. Cells exclusively expressing the p.Ser53Pro variant lacked responses to recombinant IFN-I and displayed heightened vulnerability to multiple viruses in vitro-a phenotype rescued by wild-type IFNAR2 complementation. This novel form of autosomal recessive IFNAR2 deficiency reinforces the essential role of IFN-I in viral immunity. Further studies are warranted to assess the need for population screening.

Delayed induction of type I and III interferons mediates nasal epithelial cell permissiveness to SARS-CoV-2.

The nasal epithelium is a plausible entry point for SARS-CoV-2, a site of pathogenesis and transmission, and may initiate the host response to SARS-CoV-2. Antiviral interferon (IFN) responses are critical to outcome of SARS-CoV-2. Yet little is known about the interaction between SARS-CoV-2 and innate immunity in this tissue. Here we apply single-cell RNA sequencing and proteomics to a primary cell model of human nasal epithelium differentiated at air-liquid interface. SARS-CoV-2 demonstrates widespread tropism for nasal epithelial cell types. The host response is dominated by type I and III IFNs and interferon-stimulated gene products. This response is notably delayed in onset relative to viral gene expression and compared to other respiratory viruses. Nevertheless, once established, the paracrine IFN response begins to impact on SARS-CoV-2 replication. When provided prior to infection, recombinant IFNß or IFNλ1 induces an efficient antiviral state that potently restricts SARS-CoV-2 viral replication, preserving epithelial barrier integrity. These data imply that the IFN-I/III response to SARS-CoV-2 initiates in the nasal airway and suggest nasal delivery of recombinant IFNs to be a potential chemoprophylactic strategy.

DYRK1A regulates B cell acute lymphoblastic leukemia through phosphorylation of FOXO1 and STAT3.

DYRK1A is a serine/threonine kinase encoded on human chromosome 21 (HSA21) that has been implicated in several pathologies of Down syndrome (DS), including cognitive deficits and Alzheimer's disease. Although children with DS are predisposed to developing leukemia, especially B cell acute lymphoblastic leukemia (B-ALL), the HSA21 genes that contribute to malignancies remain largely undefined. Here, we report that DYRK1A is overexpressed and required for B-ALL. Genetic and pharmacologic inhibition of DYRK1A decreased leukemic cell expansion and suppressed B-ALL development in vitro and in vivo. Furthermore, we found that FOXO1 and STAT3, transcription factors that are indispensable for B cell development, are critical substrates of DYRK1A. Loss of DYRK1A-mediated FOXO1 and STAT3 signaling disrupted DNA damage and ROS regulation, respectively, leading to preferential cell death in leukemic B cells. Thus, we reveal a DYRK1A/FOXO1/STAT3 axis that facilitates the development and maintenance of B-ALL.

Integrated Metabolomic and Transcriptomic Analysis to Characterize Cutin Biosynthesis between Low- and High-Cutin Genotypes of Capsicum chinense Jacq.

Habanero peppers constantly face biotic and abiotic stresses such as pathogen/pest infections, extreme temperature, drought and UV radiation. In addition, the fruit cutin lipid composition plays an important role in post-harvest water loss rates, which in turn causes shriveling and reduced fruit quality and storage. In this study, we integrated metabolome and transcriptome profiling pertaining to cutin in two habanero genotypes: PI 224448 and PI 257145. The fruits were selected by the waxy or glossy phenotype on their surfaces. Metabolomics analysis showed a significant variation in cutin composition, with about 6-fold higher cutin in PI 257145 than PI 224448. It also revealed that 10,16-dihydroxy hexadecanoic acid is the most abundant monomer in PI 257145. Transcriptomic analysis of high-cutin PI 257145 and low-cutin PI 224448 resulted in the identification of 2703 statistically significant differentially expressed genes, including 1693 genes upregulated and 1010 downregulated in high-cutin PI 257145. Genes and transcription factors such as GDSL lipase, glycerol-3 phosphate acyltransferase 6, long-chain acyltransferase 2, cytochrome P450 86A/77A, SHN1, ANL2 and HDG1 highly contributed to the high cutin content in PI 257145. We predicted a putative cutin biosynthetic pathway for habanero peppers based on deep transcriptome analysis. This is the first study of the transcriptome and metabolome pertaining to cutin in habanero peppers. These analyses improve our knowledge of the molecular mechanisms regulating the accumulation of cutin in habanero pepper fruits. These resources can be built on for developing cultivars with high cutin content that show resistance to biotic and abiotic stresses with superior postharvest appearance.

Severe type I interferonopathy and unrestrained interferon signaling due to a homozygous germline mutation in STAT2.

Excessive type I interferon (IFNα/ß) activity is implicated in a spectrum of human disease, yet its direct role remains to be conclusively proven. We investigated two siblings with severe early-onset autoinflammatory disease and an elevated IFN signature. Whole-exome sequencing revealed a shared homozygous missense Arg148Trp variant in STAT2, a transcription factor that functions exclusively downstream of innate IFNs. Cells bearing STAT2R148W in homozygosity (but not heterozygosity) were hypersensitive to IFNα/ß, which manifest as prolonged Janus kinase-signal transducers and activators of transcription (STAT) signaling and transcriptional activation. We show that this gain of IFN activity results from the failure of mutant STAT2R148W to interact with ubiquitin-specific protease 18, a key STAT2-dependent negative regulator of IFNα/ß signaling. These observations reveal an essential in vivo function of STAT2 in the regulation of human IFNα/ß signaling, providing concrete evidence of the serious pathological consequences of unrestrained IFNα/ß activity and supporting efforts to target this pathway therapeutically in IFN-associated disease.

The growth of a xenograft breast cancer tumor model with engineered hyaluronan-accumulating stroma is dependent on hyaluronan and independent of CD44.

Hyaluronan accumulation in the tumor microenvironment is associated with poor prognosis in several solid human cancers. To understand the role of stromal hyaluronan in tumor progression, we engineered 3T3HAS3, a hyaluronan-producing fibroblast cell line, by lentiviral transduction of Balb/c 3T3 cells with the human hyaluronan synthase 3 (HAS3) gene. 3T3HAS3 cells significantly enhanced tumor growth when co-grafted with MDA-MB-468 cells in nude mice. Immunohistochemical analysis of the xenograft tumors showed that MDA-MB-468 cells were surrounded by hyaluronan-accumulating stroma, closely resembling the morphology observed in human breast cancer specimens. Tumor growth of MDA-MB-468 + 3T3HAS3 co-grafts was greatly reduced upon hyaluronan degradation by lentiviral transduction of a human hyaluronidase gene in 3T3HAS3 cells, or by systemic administration of pegvorhyaluronidase alfa (PEGPH20). In contrast, the growth of the co-graft tumors was not inhibited when CD44 expression was reduced or ablated by small hairpin RNA-mediated CD44 knockdown in MDA-MB-468 cells, CD44 CRISPR knockout in 3T3HAS3 cells, or by grafting these cells in CD44 knockout nude mice. Collectively, these data demonstrate that tumor growth of an engineered xenograft breast cancer model with hyaluronan-accumulating stroma can be dependent on hyaluronan and independent of CD44.

A focus group study exploring student nurse's experiences of an educational intervention focused on working with people with a diagnosis of personality disorder.

WHAT IS KNOWN ON THE SUBJECT?: Research has consistently shown that poor attitudes exist in mental health care towards people with a diagnosis of personality disorder and that nurses can find working with this group of patients professionally and personally challenging. Power imbalances of practitioner over students exist on training placements. This can result in students being exposed to negative attitudes towards service users with a diagnosis of personality disorder and not feeling able to challenge these attitudes. The Knowledge and Understanding Framework (KUF) is a specialist programme of personality disorder training that has demonstrated effectiveness with qualified mental health professionals. WHAT DOES THIS PAPER ADD TO EXISTING KNOWLEDGE?: Although the subject of personality disorder is considered within preregistration education, an opportunity for a more robust approach to supporting student's nurses with this complex subject area is required (Ross & Goldner 2018). Attempts to integrate and evaluate specific educational interventions of this nature into preregistration nurse education have not been explored elsewhere. This study utilized focus groups to examine the experience of the KUF training and the perceived impact on attitudes and approaches to personality disorder of a group of nursing students who had completed the KUF programme. The students exhibited positive attitudes towards people with a diagnosis of personality disorder and confidence to influence negative attitudes in practice. The KUF shifted the students' focus from identifying patient behaviours as problematic towards an understanding of these difficulties arising from their own emotional responses. This was a small study so the results should be treated with caution. There was no follow-up once the students had qualified, so it is not clear whether such effects would endure long term. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Training students using the KUF may foster positive attitudes to people with a diagnosis of personality disorder and provide them with the skills to positively influence other colleagues practice. ABSTRACT: Introduction Negative attitudes exist in practice towards those with a diagnosis of personality disorder. Preregistration training offers the opportunity to address this by developing understanding of the diagnosis, confidence in working with people with the diagnosis and empowering new nurses to challenge prevailing attitudes. Attempts to integrate and evaluate specific educational interventions of this nature into preregistration nurse education have not been explored elsewhere. Aim To explore preregistration, nurses' experience of a programme of training focused on personality disorder and their perception of its influence on attitudes, understanding of clients and their experience of practice. Method A qualitative study using thematic analysis of two focus groups of preregistration mental health nursing students. Results Evidence of positive attitudes and confidence to supportively challenge negative attitudes in practice were found. Students showed a shift away from a focus on changing the perceived "difficult" behaviour of a client towards an understanding of their own emotional responses to the behaviours. Discussion The Knowledge and Understanding Framework training shows potential for students to change attitudes and develop progressive practice working with people with personality disorder. Implications for practice The integration of the Knowledge and Understanding Framework should be considered as part of preregistration training. Further research into the sustained influence of the training post registration is required.

The mitochondrial respiratory chain is essential for haematopoietic stem cell function.

Adult and fetal haematopoietic stem cells (HSCs) display a glycolytic phenotype, which is required for maintenance of stemness; however, whether mitochondrial respiration is required to maintain HSC function is not known. Here we report that loss of the mitochondrial complex III subunit Rieske iron-sulfur protein (RISP) in fetal mouse HSCs allows them to proliferate but impairs their differentiation, resulting in anaemia and prenatal death. RISP-null fetal HSCs displayed impaired respiration resulting in a decreased NAD+/NADH ratio. RISP-null fetal HSCs and progenitors exhibited an increase in both DNA and histone methylation associated with increases in 2-hydroxyglutarate (2HG), a metabolite known to inhibit DNA and histone demethylases. RISP inactivation in adult HSCs also impaired respiration resulting in loss of quiescence concomitant with severe pancytopenia and lethality. Thus, respiration is dispensable for adult or fetal HSC proliferation, but essential for fetal HSC differentiation and maintenance of adult HSC quiescence.

DYRK1A controls the transition from proliferation to quiescence during lymphoid development by destabilizing Cyclin D3.

Pre-B and pre-T lymphocytes must orchestrate a transition from a highly proliferative state to a quiescent one during development. Cyclin D3 is essential for these cells' proliferation, but little is known about its posttranslational regulation at this stage. Here, we show that the dual specificity tyrosine-regulated kinase 1A (DYRK1A) restrains Cyclin D3 protein levels by phosphorylating T283 to induce its degradation. Loss of DYRK1A activity, via genetic inactivation or pharmacologic inhibition in mice, caused accumulation of Cyclin D3 protein, incomplete repression of E2F-mediated gene transcription, and failure to properly couple cell cycle exit with differentiation. Expression of a nonphosphorylatable Cyclin D3 T283A mutant recapitulated these defects, whereas inhibition of Cyclin D:CDK4/6 mitigated the effects of DYRK1A inhibition or loss. These data uncover a previously unknown role for DYRK1A in lymphopoiesis, and demonstrate how Cyclin D3 protein stability is negatively regulated during exit from the proliferative phases of B and T cell development.

Dissecting the complete lipoprotein biogenesis pathway in Streptomyces scabies.

Following translocation, bacterial lipoproteins are lipidated by lipoprotein diacylglycerol transferase (Lgt) and cleaved of their signal peptides by lipoprotein signal peptidase (Lsp). In Gram-negative bacteria and mycobacteria, lipoproteins are further lipidated by lipoprotein N-acyl transferase (Lnt), to give triacylated lipoproteins. Streptomyces are unusual amongst Gram-positive bacteria because they export large numbers of lipoproteins via the twin arginine protein transport (Tat) pathway. Furthermore, some Streptomyces species encode two Lgt homologues and all Streptomyces species encode two homologues of Lnt. Here we characterize lipoprotein biogenesis in the plant pathogen Streptomyces scabies and report that lgt and lsp mutants are defective in growth and development while only moderately affected in virulence. Lipoproteins are lost from the membrane in an S. scabies lgt mutant but restored by expression of Streptomyces coelicolor lgt1 or lgt2 confirming that both encode functional Lgt enzymes. Furthermore, lipoproteins are N-acylated in Streptomyces with efficient N-acylation dependent on Lnt1 and Lnt2. However, deletion of lnt1 and lnt2 has no effect on growth, development or virulence. We thus present a detailed study of lipoprotein biogenesis in Streptomyces, the first study of Lnt function in a monoderm bacterium and the first study of bacterial lipoproteins as virulence factors in a plant pathogen.

Investigating lipoprotein biogenesis and function in the model Gram-positive bacterium Streptomyces coelicolor.

Lipoproteins are a distinct class of bacterial membrane proteins that are translocated across the cytoplasmic membrane primarily by the Sec general secretory pathway and then lipidated on a conserved cysteine by the enzyme lipoprotein diacylglycerol transferase (Lgt). The signal peptide is cleaved by lipoprotein signal peptidase (Lsp) to leave the lipid-modified cysteine at the N-terminus of the mature lipoprotein. In all Gram-positive bacteria tested to date this pathway is non-essential and the lipid attaches the protein to the outer leaflet of the cytoplasmic membrane. Here we identify lipoproteins in the model Gram-positive bacterium Streptomyces coelicolor using bioinformatics coupled with proteomic and downstream analysis. We report that Streptomyces species translocate large numbers of lipoproteins out via the Tat (twin arginine translocase) pathway and we present evidence that lipoprotein biogenesis might be an essential pathway in S. coelicolor. This is the first analysis of lipoproteins and lipoprotein biogenesis in Streptomyces and provides the first evidence that lipoprotein biogenesis could be essential in a Gram-positive bacterium. This report also provides the first experimental evidence that Tat plays a major role in the translocation of lipoproteins in a specific bacterium.

Control of hematopoietic stem cell quiescence by the E3 ubiquitin ligase Fbw7.

Ubiquitination is a posttranslational mechanism that controls diverse cellular processes. We focus here on the ubiquitin ligase Fbw7, a recently identified hematopoietic tumor suppressor that can target for degradation several important oncogenes, including Notch1, c-Myc, and cyclin E. We have generated conditional Fbw7 knockout animals and inactivated the gene in hematopoietic stem cells (HSCs), progenitors, and their differentiated progeny. Deletion of Fbw7 specifically and rapidly affects hematopoiesis in a cell-autonomous manner. Fbw7(-/-) HSCs show defective maintenance of quiescence, leading to impaired self-renewal and a severe loss of competitive repopulating capacity. Furthermore, Fbw7(-/-) progenitors are unable to colonize the thymus, leading to a profound depletion of T cell progenitors. Deletion of Fbw7 in bone marrow (BM) stem cells and progenitors leads to the stabilization of c-Myc, a transcription factor previously implicated in HSC self-renewal. On the other hand, neither Notch1 nor cyclin E is visibly stabilized in the BM of Fbw7-deficient mice. Gene expression studies of Fbw7(-/-) HSCs and hematopoietic progenitors indicate that Fbw7 regulates, through the regulation of HSC cycle entry, the transcriptional "signature" that is associated with the quiescent, self-renewing HSC phenotype.

The SCFFBW7 ubiquitin ligase complex as a tumor suppressor in T cell leukemia.

Recent studies have shown that activating mutations of NOTCH1 are responsible for the majority of T cell acute lymphoblastic leukemia (T-ALL) cases. Most of these mutations truncate its C-terminal domain, a region that is important for the NOTCH1 proteasome-mediated degradation. We report that the E3 ligase FBW7 targets NOTCH1 for ubiquitination and degradation. Our studies map in detail the amino acid degron sequence required for NOTCH1-FBW7 interaction. Furthermore, we identify inactivating FBW7 mutations in a large fraction of human T-ALL lines and primary leukemias. These mutations abrogate the binding of FBW7 not only to NOTCH1 but also to the two other characterized targets, c-Myc and cyclin E. The majority of the FBW7 mutations were present during relapse, and they were associated with NOTCH1 HD mutations. Interestingly, most of the T-ALL lines harboring FBW7 mutations were resistant to gamma-secretase inhibitor treatment and this resistance appeared to be related to the stabilization of the c-Myc protein. Our data suggest that FBW7 is a novel tumor suppressor in T cell leukemia, and implicate the loss of FBW7 function as a potential mechanism of drug resistance in T-ALL.

Transcription factor FnrP from Paracoccus denitrificans contains an iron-sulfur cluster and is activated by anoxia: identification of essential cysteine residues.

The Paracoccus denitrificans transcription factor FnrP has been characterized using artificial FNR-dependent promoter-lacZ fusion plasmids in Escherichia coli. FnrP can activate both class I and class II FNR-dependent promoters in response to anoxia but shows a marked preference for the class II promoter, where the FNR binding site is centered at -41.5 with respect to the transcription start site. FnrP was found to be inactive in an iscS mutant in vivo, demonstrating a requirement for cysteine desulfurase activity to assemble an iron-sulfur cluster in FnrP. Accordingly, an iron-sulfur cluster could be reconstituted into the purified protein in vitro using cysteine desulfurase, ferrous ions, and cysteine. Thus, FnrP is a true orthologue of FNR from E. coli and switches on target genes in response to anoxia. Inactivation of FnrP by oxygen very likely involves the oxidative disassembly of an iron-sulfur cluster. Possible ligands for the iron-sulfur cluster were identified by substituting each of the seven cysteine residues with serine and characterizing the altered proteins in vivo. Four substituted proteins showed activities less than 5% of the wild type, and so identify the four cysteines (Cys-14, Cys-17, Cys-25, and Cys-113) that are most likely to be involved in cluster ligation. The effects of N-oxides, NO-releasing compounds and a nitrosating agent on FNR and FnrP activity were investigated in vivo using the reporter system. Both proteins are very sensitive to the inclusion of sodium nitroprusside (a source of NO(+)) in defined growth media but are only moderately sensitive to those sources of NO that were tested.