The centrosome acts as a centre for microtubule organisation and plays crucial roles in cell polarity, migration, growth and division. Cep131 has recently been described as a basal body component ...essential for cilium formation, but its function in non-ciliogenic cells is unknown. We identified human Cep131 (also known as AZI1) in a screen for regulators of genome stability. We show that centrosomal localisation of Cep131 is cell-cycle-regulated and requires both an intact microtubule network and a functional dynein-dynactin transport system. Cep131 is recruited to centriolar satellites by PCM1, and localised to the centriolar core region by both pericentrin and Cep290. Depletion of Cep131 results in a reduction in proliferation rate, centriole amplification, an increased frequency of multipolar mitosis, chromosomal instability and an increase in post-mitotic DNA damage. These data therefore highlight the importance of human Cep131 for maintaining genomic integrity.
Here, we identify coiled-coil domain-containing protein 13 (Ccdc13) in a genome-wide RNA interference screen for regulators of genome stability. We establish that Ccdc13 is a newly identified ...centriolar satellite protein that interacts with PCM1, Cep290 and pericentrin and prevents the accumulation of DNA damage during mitotic transit. Depletion of Ccdc13 results in the loss of microtubule organisation in a manner similar to PCM1 and Cep290 depletion, although Ccdc13 is not required for satellite integrity. We show that microtubule regrowth is enhanced in Ccdc13-depleted cells, but slowed in cells that overexpress Ccdc13. Furthermore, in serum-starved cells, Ccdc13 localises to the basal body, is required for primary cilia formation and promotes the localisation of the ciliopathy protein BBS4 to both centriolar satellites and cilia. These data highlight the emerging link between DNA damage response factors, centriolar and peri-centriolar satellites and cilia-associated proteins and implicate Ccdc13 as a centriolar satellite protein that functions to promote both genome stability and cilia formation.
Background
Low 25‐hydroxyvitamin D levels are associated with an increased risk of cardiovascular events, but the effect of vitamin D supplementation on markers of vascular function associated with ...major adverse cardiovascular events is unclear.
Methods and Results
We conducted a systematic review and individual participant meta‐analysis to examine the effect of vitamin D supplementation on flow‐mediated dilatation of the brachial artery, pulse wave velocity, augmentation index, central blood pressure, microvascular function, and reactive hyperemia index. MEDLINE, CINAHL, EMBASE, Cochrane Central Register of Controlled Trials, and http://www.ClinicalTrials.gov were searched until the end of 2016 without language restrictions. Placebo‐controlled randomized trials of at least 4 weeks duration were included. Individual participant data were sought from investigators on included trials. Trial‐level meta‐analysis was performed using random‐effects models; individual participant meta‐analyses used a 2‐stage analytic strategy, examining effects in prespecified subgroups. 31 trials (2751 participants) were included; 29 trials (2641 participants) contributed data to trial‐level meta‐analysis, and 24 trials (2051 participants) contributed to individual‐participant analyses. Vitamin D3 daily dose equivalents ranged from 900 to 5000 IU; duration was 4 weeks to 12 months. Trial‐level meta‐analysis showed no significant effect of supplementation on macrovascular measures (flow‐mediated dilatation, 0.37% 95% confidence interval, −0.23 to 0.97; carotid‐femoral pulse wave velocity, 0.00 m/s 95% confidence interval, −0.36 to 0.37); similar results were obtained from individual participant data. Microvascular function showed a modest improvement in trial‐level data only. No consistent benefit was observed in subgroup analyses or between different vitamin D analogues.
Conclusions
Vitamin D supplementation had no significant effect on most markers of vascular function in this analysis.
Abstract
Non-invasive methods to document healing anterior cruciate ligament (ACL) structural properties could potentially identify patients at risk for revision surgery. The objective was to ...evaluate machine learning models to predict ACL failure load from magnetic resonance images (MRI) and to determine if those predictions were related to revision surgery incidence. It was hypothesized that the optimal model would demonstrate a lower mean absolute error (MAE) than the benchmark linear regression model, and that patients with a lower estimated failure load would have higher revision incidence 2 years post-surgery. Support vector machine, random forest, AdaBoost, XGBoost, and linear regression models were trained using MRI T
2
* relaxometry and ACL tensile testing data from minipigs (n = 65). The lowest MAE model was used to estimate ACL failure load for surgical patients at 9 months post-surgery (n = 46) and dichotomized into low and high score groups via Youden’s J statistic to compare revision incidence. Significance was set at alpha = 0.05. The random forest model decreased the failure load MAE by 55% (Wilcoxon signed-rank test: p = 0.01) versus the benchmark. The low score group had a higher revision incidence (21% vs. 5%; Chi-square test: p = 0.09). ACL structural property estimates via MRI may provide a biomarker for clinical decision making.
Through an RNAi-based screen for previously uncharacterized regulators of genome stability, we have identified the human protein C5orf45 as an important factor in preventing the accumulation of DNA ...damage in human cells. Here, we functionally characterize C5orf45 as a binding partner of the MRE11-RAD50-NBS1 (MRN) damage-sensing complex. Hence, we rename C5orf45 as MRNIP for MRN-interacting protein (MRNIP). We find that MRNIP is rapidly recruited to sites of DNA damage. Cells depleted of MRNIP display impaired chromatin loading of the MRN complex, resulting in reduced DNA end resection and defective ATM-mediated DNA damage signaling, a reduced ability to repair DNA breaks, and radiation sensitivity. Finally, we show that MRNIP phosphorylation on serine 115 leads to its nuclear localization, and this modification is required for MRNIP’s role in promoting genome stability. Collectively, these data reveal that MRNIP is an important component of the human DNA damage response.
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•C5orf45/MRNIP is identified as a MRN-interacting protein•MRNIP facilitates MRN complex association with chromatin•MRNIP promotes efficient ATM-mediated DDR signaling•MRNIP prevents accumulation of DNA damage in human cells
Staples et al. describe the cellular function of the human protein C5orf45. They find that C5orf45 physically interacts with the MRN complex and rename it MRN-interacting protein. MRNIP acts as an accessory factor to the MRN complex to facilitate robust ATM-mediated signaling in response to DNA damage.
Genomic damage can feature DNA-protein crosslinks whereby their acute accumulation is utilized to treat cancer and progressive accumulation causes neurodegeneration. This is typified by tyrosyl DNA ...phosphodiesterase 1 (TDP1), which repairs topoisomerase-mediated chromosomal breaks. Although TDP1 levels vary in multiple clinical settings, the mechanism underpinning this variation is unknown. We reveal that TDP1 is controlled by ubiquitylation and identify UCHL3 as the deubiquitylase that controls TDP1 proteostasis. Depletion of UCHL3 increases TDP1 ubiquitylation and turnover rate and sensitizes cells to TOP1 poisons. Overexpression of UCHL3, but not a catalytically inactive mutant, suppresses TDP1 ubiquitylation and turnover rate. TDP1 overexpression in the topoisomerase therapy-resistant rhabdomyosarcoma is driven by UCHL3 overexpression. In contrast, UCHL3 is downregulated in spinocerebellar ataxia with axonal neuropathy (SCAN1), causing elevated levels of TDP1 ubiquitylation and faster turnover rate. These data establish UCHL3 as a regulator of TDP1 proteostasis and, consequently, a fine-tuner of protein-linked DNA break repair.
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•TDP1 proteostasis is controlled by a UCHL3-dependent ubiquitylation mechanism•UCHL3 depletion sensitizes mammalian cells to TOP1 inhibitors•Increased TDP1 protein in rhabdomyosarcoma is driven by UCHL3 upregulation•Decreased TDP1 protein in spinocerebellar ataxia is driven by UCHL3 downregulation
Deciphering the mechanisms regulating protein homeostasis is clinically important. Liao et al. identify UCHL3 as a key player in ubiquitylation and turnover of the DNA repair enzyme TDP1. Disruption of TDP1’s ubiquitylation status causes neurological disease or resistance to topoisomerase I-targeting chemotherapy in cancer.
Objective To examine how children’s appraisals of maternal involvement in coping with diabetes are associated with adherence, metabolic control, and quality of life across adolescence. Methods ...Children (N = 127, ages 10–15 years) with type 1 diabetes completed measures of adherence, quality of life, and appraisals of mothers’ involvement in dealing with diabetes problems (i.e., mother appraised as uninvolved, controlling, or collaborative). Metabolic control was indexed through medical records. Results Regardless of age or sex of child, appraised maternal uninvolvement was associated with poorer adherence and quality of life, while appraised collaboration was associated with better adherence and metabolic control. There was evidence that the association between appraised collaboration and metabolic control was partially mediated by adherence. Appraised control was associated with poorer adherence among older, but not younger, children and with poorer quality of life among older females but not among older males or younger children of either sex. Conclusions Maintaining maternal involvement in diabetes care is important across ages 10 to 15, but the optimal form of this involvement may need to be adjusted to be consistent with the child’s level of development. The present findings suggest that better adherence is seen across age when mothers are viewed as collaborating with, as opposed to controlling, their child when dealing with diabetes problems.
Antitumor activity in preclinical models and a phase I study of patients with dedifferentiated liposarcoma (DD-LPS) was observed with selinexor. We evaluated the clinical benefit of selinexor in ...patients with previously treated DD-LPS whose sarcoma progressed on approved agents.
SEAL was a phase II-III, multicenter, randomized, double-blind, placebo-controlled study. Patients age 12 years or older with advanced DD-LPS who had received two-five lines of therapy were randomly assigned (2:1) to selinexor (60 mg) or placebo twice weekly in 6-week cycles (crossover permitted). The primary end point was progression-free survival (PFS). Patients who received at least one dose of study treatment were included for safety analysis (ClinicalTrials.gov identifier: NCT02606461).
Two hundred eighty-five patients were enrolled (selinexor, n = 188; placebo, n = 97). PFS was significantly longer with selinexor versus placebo: hazard ratio (HR) 0.70 (95% CI, 0.52 to 0.95; one-sided
= .011; medians 2.8
2.1 months), as was time to next treatment: HR 0.50 (95% CI, 0.37 to 0.66; one-sided
< .0001; medians 5.8
3.2 months). With crossover, no difference was observed in overall survival. The most common treatment-emergent adverse events of any grade versus grade 3 or 4 with selinexor were nausea (151 80.7%
11 5.9), decreased appetite (113 60.4%
14 7.5%), and fatigue (96 51.3%
12 6.4%). Four (2.1%) and three (3.1%) patients died in the selinexor and placebo arms, respectively. Exploratory RNA sequencing analysis identified that the absence of
expression was associated with longer PFS with selinexor compared with placebo (median 6.9
2.2 months; HR, 0.19;
= .001).
Patients with advanced, refractory DD-LPS showed improved PFS and time to next treatment with selinexor compared with placebo. Supportive care and dose reductions mitigated side effects of selinexor. Prospective validation of
expression as a predictive biomarker for selinexor in DD-LPS is warranted.
Objective To examine how autonomy and pubertal status explain age decreases in maternal involvement in type 1 diabetes management across adolescence, how they relate to metabolic control, and the ...reasons that guide declines in maternal involvement. Methods One hundred twenty-seven children ages 10–15 years with type 1 diabetes and their mothers participated. Data included maternal and child report of diabetes management, child report of autonomy level, maternal report of pubertal status, maternal reports of reasons for transfer of diabetes responsibility, and glycosylated hemoglobin (Hba1c) values. Results Autonomy and pubertal status partially mediated age effects on reports of maternal involvement. Mothers' reasons for transferring responsibility included responding to the child's competence, promoting competence and maturity in their child, and minimizing hassles and conflict. The transfer of diabetes responsibility from mother to child without sufficient autonomy and when pubertal status was low was related to higher Hba1c values. Conclusions The importance of chronological age for changes in maternal involvement suggests the need to examine mothers' and adolescents' developmental expectations for diabetes management. The reasons for transferring responsibility from mother to child suggest many avenues for intervention.
It was recently discovered that vertebrate genomes contain multiple endogenised nucleotide sequences derived from the non-retroviral RNA bornavirus. Strikingly, some of these elements have been ...evolutionary maintained as open reading frames in host genomes for over 40 million years, suggesting that some endogenised bornavirus-derived elements (EBL) might encode functional proteins. EBLN1 is one such element established through endogenisation of the bornavirus N gene (BDV N). Here, we functionally characterise human EBLN1 as a novel regulator of genome stability. Cells depleted of human EBLN1 accumulate DNA damage both under non-stressed conditions and following exogenously induced DNA damage. EBLN1-depleted cells also exhibit cell cycle abnormalities and defects in microtubule organisation as well as premature centrosome splitting, which we attribute in part, to improper localisation of the nuclear envelope protein TPR. Our data therefore reveal that human EBLN1 possesses important cellular functions within human cells, and suggest that other EBLs present within vertebrate genomes may also possess important cellular functions.
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