Structural basis for RING-Cys-Relay E3 ligase activity and its role in axon integrity.

MYCBP2 is a ubiquitin (Ub) E3 ligase (E3) that is essential for neurodevelopment and regulates axon maintenance. MYCBP2 transfers Ub to nonlysine substrates via a newly discovered RING-Cys-Relay (RCR) mechanism, where Ub is relayed from an upstream cysteine to a downstream substrate esterification site. The molecular bases for E2-E3 Ub transfer and Ub relay are unknown. Whether these activities are linked to the neural phenotypes is also unclear. We describe the crystal structure of a covalently trapped E2~Ub:MYCBP2 transfer intermediate revealing key structural rearrangements upon E2-E3 Ub transfer and Ub relay. Our data suggest that transfer to the dynamic upstream cysteine, whilst mitigating lysine activity, requires a closed-like E2~Ub conjugate with tempered reactivity, and Ub relay is facilitated by a helix-coil transition. Furthermore, neurodevelopmental defects and delayed injury-induced degeneration in RCR-defective knock-in mice suggest its requirement, and that of substrate esterification activity, for normal neural development and programmed axon degeneration

Activity-based E3 ligase profiling uncovers an E3 ligase with esterification activity

Ubiquitination is initiated by transfer of ubiquitin (Ub) from a ubiquitin-activating enzyme (E1) to a ubiquitin-conjugating enzyme (E2), producing a covalently linked intermediate (E2-Ub)(1). Ubiquitin ligases (E3s) of the 'really interesting new gene' (RING) class recruit E2-Ub via their RING domain and then mediate direct transfer of ubiquitin to substrates(2). By contrast, 'homologous to E6-AP carboxy terminus' (HECT) E3 ligases undergo a catalytic cysteine-dependent transthiolation reaction with E2-Ub, forming a covalent E3-Ub intermediate(3,4). Additionally, RING-between-RING (RBR) E3 ligases have a canonical RING domain that is linked to an ancillary domain. This ancillary domain contains a catalytic cysteine that enables a hybrid RING-HECT mechanism(5). Ubiquitination is typically considered a post-translational modification of lysine residues, as there are no known human E3 ligases with non-lysine activity. Here we perform activity-based protein profiling of HECT or RBR-like E3 ligases and identify the neuron-associated E3 ligase MYCBP2 (also known as PHR1) as the apparent single member of a class of RING-linked E3 ligase with esterification activity and intrinsic selectivity for threonine over serine. MYCBP2 contains two essential catalytic cysteine residues that relay ubiquitin to its substrate via thioester intermediates. Crystallographic characterization of this class of E3 ligase, which we designate RING-Cys-relay (RCR), provides insights into its mechanism and threonine selectivity. These findings implicate non-lysine ubiquitination in cellular regulation of higher eukaryotes and suggest that E3 enzymes have an unappreciated mechanistic diversity

Women with endometriosis have higher comorbidities: Analysis of domestic data in Taiwan

AbstractEndometriosis, defined by the presence of viable extrauterine endometrial glands and stroma, can grow or bleed cyclically, and possesses characteristics including a destructive, invasive, and metastatic nature. Since endometriosis may result in pelvic inflammation, adhesion, chronic pain, and infertility, and can progress to biologically malignant tumors, it is a long-term major health issue in women of reproductive age. In this review, we analyze the Taiwan domestic research addressing associations between endometriosis and other diseases. Concerning malignant tumors, we identified four studies on the links between endometriosis and ovarian cancer, one on breast cancer, two on endometrial cancer, one on colorectal cancer, and one on other malignancies, as well as one on associations between endometriosis and irritable bowel syndrome, one on links with migraine headache, three on links with pelvic inflammatory diseases, four on links with infertility, four on links with obesity, four on links with chronic liver disease, four on links with rheumatoid arthritis, four on links with chronic renal disease, five on links with diabetes mellitus, and five on links with cardiovascular diseases (hypertension, hyperlipidemia, etc.). The data available to date support that women with endometriosis might be at risk of some chronic illnesses and certain malignancies, although we consider the evidence for some comorbidities to be of low quality, for example, the association between colon cancer and adenomyosis/endometriosis. We still believe that the risk of comorbidity might be higher in women with endometriosis than that we supposed before. More research is needed to determine whether women with endometriosis are really at risk of these comorbidities

Placebo effects on all‐cause mortality of patients with COVID‐19 in randomized controlled trials of interleukin 6 antagonists: a systematic review and network meta‐analysis

Aim: Many randomized controlled trials (RCTs) have investigated the use of interleukin 6 antagonists for the treatment of coronavirus disease 2019 (COVID-19), yielding inconsistent results. This network meta-analysis (NMA) aimed to identify the source of these inconsistent results by reassessing whether participants treated with standard of care (SoC) plus placebo have different all-cause mortality from those treated with SoC alone and to reevaluate the efficacy of interleukin 6 antagonists in the treatment of COVID-19. Methods: We conducted a systematic search for relevant RCTs from the inception of electronic databases through 1 September 2022. The primary outcome was all-cause mortality. The secondary outcomes were the incidences of major medical events, secondary infections, all-cause discontinuation, and serious adverse events. Results: The results of NMA of 33 RCTs showed that patients with COVID-19 treated with SoC plus placebo had lower odds of all-cause mortality than those who received SoC alone (OR, 0.75 [95% confidence interval, 0.58-0.97]). This finding remained consistent after excluding studies with no incident deaths. In addition, when we consider the impact of the widely promoted COVID-19 vaccination and newly developed antiviral treatment strategy, the results from the analysis of the RCT published in 2021 and 2022 remained similar. Conclusion: These findings suggest the potential influence of placebo effects on the treatment outcomes of COVID-19 in RCTs. When evaluating the efficacy of treatment strategies for COVID-19, it is crucial to consider the use of placebo in the design of clinical trials

The difference in all-cause mortality between COVID-19 patients treated with standard of care plus placebo and those treated with standard of care alone: a network meta-analysis of randomised controlled trials of immunomodulatory kinase inhibitors

Objectives: The aim of this network meta-analysis (NMA) was to assess whether participants assigned to a placebo and standard of care (SoC) group had different major coronavirus disease 2019 (COVID-19)-related outcomes than those assigned to SoC alone. Design: Frequentist model-based NMA. Setting: We searched for randomised controlled trials (RCTs) of Janus kinase/Bruton tyrosine kinase inhibitors for the management of COVID-19. Participants: Patients with COVID-19 infection. Main outcome measures: The primary outcome was the 28-day all-cause mortality, and secondary outcomes were: (1) use of mechanical ventilation; (2) secondary bacterial infection; (3) acceptability (i.e. drop-out rate); and (4) safety (i.e. serious adverse events). We conducted an NMA using the frequentist model. Effect sizes were estimated using odds ratios (ORs) with 95% confidence intervals (95% CIs). Results: We identified 14 eligible RCTs enrolling a total of 13,568 participants with COVID-19. Participants assigned to placebo plus SoC had a significantly higher risk of 28-day all-cause mortality than those receiving SoC alone (OR = 1.39, 95% CI = 1.07-1.79). This finding did not change substantially by subgroup analysis stratified by epidemiology factor, pandemic history progression and statistical methodologic consideration. In addition, none of the treatments investigated were associated with a significantly different risk of secondary bacterial infection, acceptability or safety compared with the SoC group. Conclusions: This NMA suggested a higher all-cause mortality in patients treated with placebo plus SoC compared with those treated with SoC alone. However, caution is advised in interpreting these results due to the absence of a direct head-to-head comparison. Future research should critically evaluate the necessity of placebo administration in COVID-19 RCTs and consider alternative study designs to minimise potential biases. Trial registration: The current study was approved by the Institutional Review Board of the Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (TSGHIRB No. B-109-29) and registered in PROSPERO (CRD42022376217)

Pharmacological interventions and hormonal therapies for depressive symptoms in peri- and post-menopausal women: a network meta-analysis of randomized controlled trials

Although significant portion of women experience depressive symptoms during or after menopausal transition, there has been considerable controversy over the benefits of hormone replacement therapy (HRT) and antidepressants due to insufficient evidence supporting the superiority of either treatment. This frequentist model based network meta-analysis (NMA) included randomized controlled trials (RCTs) of menopausal depression symptoms management in menopausal women. Seventy RCTs involving a total of 18,530 women (mean age 62.5) were analyzed. The results demonstrated that fluoxetine plus oral HRT [standardized mean difference (SMD)=-1.59, 95% confidence interval (95%CIs)=-2.69 to -0.50] were associated with the largest improvement in depressive symptoms than placebos in overall menopausal women. Similar findings were also noted in the subgroup of participants with a definite diagnosis of depression, while no pharmacological or hormone replacement therapy was better than placebo in the subgroup of post-menopausal women (amenorrhea > 1 year) or in patients without diagnosis of depression. This NMA presented evidence that fluoxetine plus HRT may be beneficial to menopausal women with a definite diagnosis of depression but not to those without depression or post-menopausal women

Prophylaxis for paediatric emergence delirium in desflurane-based anaesthesia: a network meta-analysis

Purpose: The prevalence of postoperative emergence delirium in paediatric patients (pedED) following desflurane anaesthesia is considerably high at 50–80%. Although several pharmacological prophylactic strategies have been introduced to reduce the risk of pedED, conclusive evidence about the superiority of these individual regimens is lacking. The aim of the current study was to assess the potential prophylactic effect and safety of individual pharmacotherapies in the prevention of pedED following desflurane anaesthesia.Methods: This frequentist model network meta-analysis (NMA) of randomized controlled trials (RCTs) included peer-reviewed RCTs of either placebo-controlled or active-controlled design in paediatric patients under desflurane anaesthesia.Results: Seven studies comprising 573 participants were included. Overall, the ketamine + propofol administration [odds ratio (OR) = 0.05, 95% confidence intervals (95%CIs) 0.01–0.33], dexmedetomidine alone (OR = 0.13, 95%CIs 0.05–0.31), and propofol administration (OR = 0.30, 95%CIs 0.10–0.91) were associated with a significantly lower incidence of pedED than the placebo/control groups. In addition, only gabapentin and dexmedetomidine were associated with a significantly higher improvement in the severity of emergence delirium than the placebo/control groups. Finally, the ketamine + propofol administration was associated with the lowest incidence of pedED, whereas gabapentin was associated with the lowest severity of pedED among all of the pharmacologic interventions studied.Conclusions: The current NMA showed that ketamine + propofol administration was associated with the lowest incidence of pedED among all of the pharmacologic interventions studied. Future large-scale trials to more fully elucidate the comparative benefits of different combination regimens are warranted.</p