Hydrocortisone in Severe Community-Acquired Pneumonia.

BACKGROUND: Whether the antiinflammatory and immunomodulatory effects of glucocorticoids may decrease mortality among patients with severe community-acquired pneumonia is unclear. METHODS: In this phase 3, multicenter, double-blind, randomized, controlled trial, we assigned adults who had been admitted to the intensive care unit (ICU) for severe community-acquired pneumonia to receive intravenous hydrocortisone (200 mg daily for either 4 or 7 days as determined by clinical improvement, followed by tapering for a total of 8 or 14 days) or to receive placebo. All the patients received standard therapy, including antibiotics and supportive care. The primary outcome was death at 28 days. RESULTS: A total of 800 patients had undergone randomization when the trial was stopped after the second planned interim analysis. Data from 795 patients were analyzed. By day 28, death had occurred in 25 of 400 patients (6.2%; 95% confidence interval [CI], 3.9 to 8.6) in the hydrocortisone group and in 47 of 395 patients (11.9%; 95% CI, 8.7 to 15.1) in the placebo group (absolute difference, -5.6 percentage points; 95% CI, -9.6 to -1.7; P = 0.006). Among the patients who were not undergoing mechanical ventilation at baseline, endotracheal intubation was performed in 40 of 222 (18.0%) in the hydrocortisone group and in 65 of 220 (29.5%) in the placebo group (hazard ratio, 0.59; 95% CI, 0.40 to 0.86). Among the patients who were not receiving vasopressors at baseline, such therapy was initiated by day 28 in 55 of 359 (15.3%) of the hydrocortisone group and in 86 of 344 (25.0%) in the placebo group (hazard ratio, 0.59; 95% CI, 0.43 to 0.82). The frequencies of hospital-acquired infections and gastrointestinal bleeding were similar in the two groups; patients in the hydrocortisone group received higher daily doses of insulin during the first week of treatment. CONCLUSIONS: Among patients with severe community-acquired pneumonia being treated in the ICU, those who received hydrocortisone had a lower risk of death by day 28 than those who received placebo. (Funded by the French Ministry of Health; CAPE COD ClinicalTrials.gov number, NCT02517489.).

Home continuous positive airway pressure therapy in infants: a single-center experience.

STUDY OBJECTIVES: There are limited data on indications and outcomes of home continuous positive airway pressure (CPAP) therapy in the first year of life. We aimed to analyze the clinical, demographic, and polysomnographic characteristics of a cohort of children initiated on home CPAP for treatment of sleep-disordered breathing and as respiratory support in the first year of life. METHODS: Children started on CPAP in the first year of life at the Queensland Children's Hospital were retrospectively evaluated for clinical and demographic parameters, underlying diagnoses, respiratory support, airway surgical intervention, and polysomnography results at baseline and on CPAP. RESULTS: Twenty-nine infants (median age [interquartile range] at CPAP initiation, 182 days [126-265.5 days]) were included. The underlying etiology included Trisomy 21 (n = 6), craniofacial syndromes (n = 5), hypotonia (n = 8; 5 with noncraniofacial syndrome), airway malacia (n = 5), skeletal dysplasia (n = 2), nonsyndromic upper airway obstruction (n = 2), and chronic neonatal lung disease (n = 1). The median (interquartile range) obstructive apnea-hypopnea index was 14 events/h (6.2-31 events/h) at CPAP initiation, which improved on CPAP to 3.4 events/h (1.4-6.4 events/h). The median (interquartile range) transcutaneous CO2 max remained unchanged on CPAP (56.6 mm Hg [49-66.5 mm Hg] pre-CPAP vs 54.9 mm Hg [47-62 mm Hg] on CPAP). Fifteen children needed surgical airway intervention (11 pre-CPAP and 4 post-CPAP). CPAP therapy could be successfully stopped in 9 children, 2 children needed tracheostomy, and 1 child died during the follow-up period. CONCLUSIONS: Home CPAP as respiratory support is an effective long-term therapy in infancy, and these patients can be weaned from CPAP therapy even if it was initiated early. Prospective studies with predefined criteria for CPAP initiation and cessation would help ascertain long-term outcomes in this poorly researched group. CITATION: Joshi SS, Sivapalan D, Leclerc M-J, Kapur N. Home continuous positive airway pressure therapy in infants: a single-center experience. J Clin Sleep Med. 2023;19(3):473-477.

Factors affecting residential staff's role in supporting the sexuality of adults with intellectual disabilities.

BACKGROUND: For adults with intellectual disabilities living in a residential care facility, support staff, who are an integral part of their daily lives, can play an important role in supporting their sexuality. Even though multiple programmes exist, barriers remain when it comes to their application. This study aimed to identify factors affecting residential staff's perception of their role in supporting the sexuality of adults with intellectual disabilities living in a residential care facility as well as facilitators and barriers to that support. METHOD: Semi-structured interviews were conducted with 12 support staff. RESULTS: A thematic analysis revealed four factors, namely support staff's role, facilitators and barriers, sexuality of residents with intellectual disabilities and policies and regulations. CONCLUSION: Results illustrate the importance of expanding support staff's knowledge, clarifying procedures for implementing the support staff's role and establishing a clear practise framework.

Symptom care approach to noninvasive ventilatory support in children with complex neural disability.

STUDY OBJECTIVES: Sleep-disordered breathing is a major cause of morbidity and mortality among pediatric patients with severe neurological disabilities such as cerebral palsy. Despite increasing use of noninvasive ventilation (NIV) in this group, there remains a lack of consensus about its role and indications. We aim to explore the indications, acceptability, and outcomes of a cohort of children with severe, complex neurological disability and sleep-disordered breathing, managed with NIV. METHODS: Data were retrospectively extracted on children with severe neurological disabilities (Gross Motor Function Classification System V equivalent) initiated on NIV in Queensland over a 5-year period. Demographic, clinical, hospitalization, and polysomnography data were collected, as well as caregiver-reported side effects and NIV adherence. RESULTS: Fourteen (median age 9.1 years; 6 female) children were included, 8 with cerebral palsy and 6 with other complex neurological disabilities. Obstructive sleep apnea was the most common indication for NIV (n = 12). The median (interquartile range) apnea-hypopnea index improved on NIV [pre-NIV 21.3 (interquartile range 10.0-28.2) vs post-NIV 12.2 (interquartile range 2.8-15.2)], although this was not statistically significant. There was significant improvement in proportion of time spent with SpO2 < 95% (22.2% pre-NIV vs 7.85% post-NIV; P < .05). Reported side effects were minimal. There was no reduction in hospital admissions in the 12 months post-NIV initiation. CONCLUSIONS: Our findings suggest that NIV improves polysomnography parameters among children with severe neurological disability. Long-term outcomes and overall impact on quality of life remain unclear. Ethical issues and overall benefit must be considered before embarking on this mode of therapy. CITATION: Morrison L, Suresh S, Leclerc MJ, Kapur N. Symptom care approach to noninvasive ventilatory support in children with complex neural disability. J Clin Sleep Med. 2022;18(4):1145-1151.

Exploring Insecure Romantic Attachment and Justifications for the Use of Intimate Partner Psychological Aggression in Couples.

The attachment theory has commonly been used to examine intimate partner psychological aggression (IPPA), but few studies have examined its association with self-reported justifications for one's own use of IPPA. Behaviors, including the use of IPPA, are influenced, maintained, and function within the context of their justifications, highlighting the importance of investigating these justifications to obtain a clearer picture of IPPA. This study examined whether insecure romantic attachment (i.e., attachment anxiety and attachment avoidance) in both partners of a couple was associated with their justifications for their own use of IPPA. A community sample of 81 mixed-sex couples who reported using IPPA in the last year completed self-reported questionnaires on adult romantic attachment and their justifications for their use of IPPA. Results of a path analysis based on the actor-partner interdependence model revealed moderate positive associations between attachment anxiety and one's use of internal and external justifications for their IPPA perpetration in men and women. An unexpected dyadic positive association is discussed. These results suggest that the use of justifications for one's use of IPPA may reflect a strategy of hyperactivation that could contribute to the cycle of psychological aggression. Uncovering the function of these justifications could provide important therapeutic benefits, which are discussed in the study's implications.

Traumatic stress in Canadian lawyers: A longitudinal study.

OBJECTIVE: Numerous professions are considered at risk of developing work-related posttraumatic stress disorder (PTSD), as per DSM-5. This study sought to identify the prevalence of PTSD among lawyers and its associated work and non-work-related risk and moderating factors. METHOD: A cross-national sample of Canadian lawyers (N = 169) completed two online surveys 8 months apart. RESULTS: Seven percent of lawyers working with trauma-related cases met the criteria for probable PTSD at study entry only, 7.0% met them at study endpoint only, and an additional 3.5% of the sample met the criteria at both time points, yielding a current (past-month) prevalence of 10.4% and an 8-month cumulative prevalence of 17.5%. Beyond a past diagnosis of PTSD, the most important risk factor was the number of years on the job. Parenthood represented a mitigating factor. Ultimately, the more time spent working on trauma-related cases, the more severe were the PTSD symptoms, although this relationship was moderated by perceived quality of life and work-family balance. CONCLUSIONS: Lawyers exposed to trauma-related cases represent an at-risk group for PTSD. The findings highlight the powerful impacts that interpersonal relationships and self-care may have in buffering this health hazard. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Inhaled amikacin versus placebo to prevent ventilator-associated pneumonia: the AMIKINHAL double-blind multicentre randomised controlled trial protocol.

INTRODUCTION: Pre-emptive inhaled antibiotics may be effective to reduce the occurrence of ventilator-associated pneumonia among critically ill patients. Meta-analysis of small sample size trials showed a favourable signal. Inhaled antibiotics are associated with a reduced emergence of antibiotic resistant bacteria. The aim of this trial is to evaluate the benefit of a 3-day course of inhaled antibiotics among patients undergoing invasive mechanical ventilation for more than 3 days on the occurrence of ventilator-associated pneumonia. METHODS AND ANALYSIS: Academic, investigator-initiated, parallel two group arms, double-blind, multicentre superiority randomised controlled trial. Patients invasively ventilated more than 3 days will be randomised to receive 20 mg/kg inhaled amikacin daily for 3 days or inhaled placebo (0.9% Sodium Chloride). Occurrence of ventilator-associated pneumonia will be recorded based on a standardised diagnostic framework from randomisation to day 28 and adjudicated by a centralised blinded committee. ETHICS AND DISSEMINATION: The protocol and amendments have been approved by the regional ethics review board and French competent authorities (Comité de protection des personnes Ouest I, No.2016-R29). All patients will be included after informed consent according to French law. Results will be disseminated in international scientific journals. TRIAL REGISTRATION NUMBERS: EudraCT 2016-001054-17 and NCT03149640.

Natural climate solutions for Canada.

Alongside the steep reductions needed in fossil fuel emissions, natural climate solutions (NCS) represent readily deployable options that can contribute to Canada's goals for emission reductions. We estimate the mitigation potential of 24 NCS related to the protection, management, and restoration of natural systems that can also deliver numerous co-benefits, such as enhanced soil productivity, clean air and water, and biodiversity conservation. NCS can provide up to 78.2 (41.0 to 115.1) Tg CO2e/year (95% CI) of mitigation annually in 2030 and 394.4 (173.2 to 612.4) Tg CO2e cumulatively between 2021 and 2030, with 34% available at ≤CAD 50/Mg CO2e. Avoided conversion of grassland, avoided peatland disturbance, cover crops, and improved forest management offer the largest mitigation opportunities. The mitigation identified here represents an important potential contribution to the Paris Agreement, such that NCS combined with existing mitigation plans could help Canada to meet or exceed its climate goals.

Cognitive parameters in children with mild obstructive sleep disordered breathing.

PURPOSE: Sleep disordered breathing (SDB) in children is commonly described as a continuum from primary snoring (PS) to obstructive sleep apnea (OSA), based on apnea indices from polysomnography (PSG). This study evaluated the difference in neurocognitive and behavioral parameters, prior to treatment, in symptomatic pre-school children with PSG-diagnosed OSA and PS. METHODS: All children had positive Pediatric Sleep Questionnaire (PSQ) results and were deemed suitable for adenotonsillectomy by an ENT surgeon. Neurocognitive and behavioral data were analyzed in pre-school children at recruitment for the POSTA study (The Pre-School OSA Tonsillectomy Adenoidectomy Study). Data were compared between PS and OSA groups, with Obstructive Apnea-Hypopnea Index, OAHI < 1/h or 1-10/h, respectively. RESULTS: Ninety-one children were enrolled, including 52 with OSA and 39 with PS. Distribution of IQ (using Brief Intellectual Ability, BIA) was slightly skewed towards higher values compared with the reference population. No significant differences were found in neurocognitive or behavioral parameters for children with OSA versus those with PS. DISCUSSION: Neurocognitive and behavioral parameters were similar in pre-school children symptomatic for OSA, regardless of whether or not PSG diagnosed PS or OSA. Despite having identical symptoms, children with PS on PSG are often treated conservatively, whereas those with OSA on PSG are considered for adenotonsillectomy. This study demonstrates that, regardless of whether or not PS or OSA is diagnosed on PSG, symptoms, neurocognition, and behavior are identical in these groups. We conclude that symptoms and behavioral disturbances should be considered in addition to OAHI when determining the need for treatment. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials registration number ACTRN12611000021976.

Effect of Hydrocortisone on 21-Day Mortality or Respiratory Support Among Critically Ill Patients With COVID-19: A Randomized Clinical Trial.

Importance: Coronavirus disease 2019 (COVID-19) is associated with severe lung damage. Corticosteroids are a possible therapeutic option. Objective: To determine the effect of hydrocortisone on treatment failure on day 21 in critically ill patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and acute respiratory failure. Design, Setting, and Participants: Multicenter randomized double-blind sequential trial conducted in France, with interim analyses planned every 50 patients. Patients admitted to the intensive care unit (ICU) for COVID-19-related acute respiratory failure were enrolled from March 7 to June 1, 2020, with last follow-up on June 29, 2020. The study intended to enroll 290 patients but was stopped early following the recommendation of the data and safety monitoring board. Interventions: Patients were randomized to receive low-dose hydrocortisone (n = 76) or placebo (n = 73). Main Outcomes and Measures: The primary outcome, treatment failure on day 21, was defined as death or persistent dependency on mechanical ventilation or high-flow oxygen therapy. Prespecified secondary outcomes included the need for tracheal intubation (among patients not intubated at baseline); cumulative incidences (until day 21) of prone position sessions, extracorporeal membrane oxygenation, and inhaled nitric oxide; Pao2:Fio2 ratio measured daily from day 1 to day 7, then on days 14 and 21; and the proportion of patients with secondary infections during their ICU stay. Results: The study was stopped after 149 patients (mean age, 62.2 years; 30.2% women; 81.2% mechanically ventilated) were enrolled. One hundred forty-eight patients (99.3%) completed the study, and there were 69 treatment failure events, including 11 deaths in the hydrocortisone group and 20 deaths in the placebo group. The primary outcome, treatment failure on day 21, occurred in 32 of 76 patients (42.1%) in the hydrocortisone group compared with 37 of 73 (50.7%) in the placebo group (difference of proportions, -8.6% [95.48% CI, -24.9% to 7.7%]; P = .29). Of the 4 prespecified secondary outcomes, none showed a significant difference. No serious adverse events were related to the study treatment. Conclusions and Relevance: In this study of critically ill patients with COVID-19 and acute respiratory failure, low-dose hydrocortisone, compared with placebo, did not significantly reduce treatment failure (defined as death or persistent respiratory support) at day 21. However, the study was stopped early and likely was underpowered to find a statistically and clinically important difference in the primary outcome. Trial Registration: ClinicalTrials.gov Identifier: NCT02517489.

Association Between Administration of Systemic Corticosteroids and Mortality Among Critically Ill Patients With COVID-19: A Meta-analysis.

Importance: Effective therapies for patients with coronavirus disease 2019 (COVID-19) are needed, and clinical trial data have demonstrated that low-dose dexamethasone reduced mortality in hospitalized patients with COVID-19 who required respiratory support. Objective: To estimate the association between administration of corticosteroids compared with usual care or placebo and 28-day all-cause mortality. Design, Setting, and Participants: Prospective meta-analysis that pooled data from 7 randomized clinical trials that evaluated the efficacy of corticosteroids in 1703 critically ill patients with COVID-19. The trials were conducted in 12 countries from February 26, 2020, to June 9, 2020, and the date of final follow-up was July 6, 2020. Pooled data were aggregated from the individual trials, overall, and in predefined subgroups. Risk of bias was assessed using the Cochrane Risk of Bias Assessment Tool. Inconsistency among trial results was assessed using the I2 statistic. The primary analysis was an inverse variance-weighted fixed-effect meta-analysis of overall mortality, with the association between the intervention and mortality quantified using odds ratios (ORs). Random-effects meta-analyses also were conducted (with the Paule-Mandel estimate of heterogeneity and the Hartung-Knapp adjustment) and an inverse variance-weighted fixed-effect analysis using risk ratios. Exposures: Patients had been randomized to receive systemic dexamethasone, hydrocortisone, or methylprednisolone (678 patients) or to receive usual care or placebo (1025 patients). Main Outcomes and Measures: The primary outcome measure was all-cause mortality at 28 days after randomization. A secondary outcome was investigator-defined serious adverse events. Results: A total of 1703 patients (median age, 60 years [interquartile range, 52-68 years]; 488 [29%] women) were included in the analysis. Risk of bias was assessed as "low" for 6 of the 7 mortality results and as "some concerns" in 1 trial because of the randomization method. Five trials reported mortality at 28 days, 1 trial at 21 days, and 1 trial at 30 days. There were 222 deaths among the 678 patients randomized to corticosteroids and 425 deaths among the 1025 patients randomized to usual care or placebo (summary OR, 0.66 [95% CI, 0.53-0.82]; P < .001 based on a fixed-effect meta-analysis). There was little inconsistency between the trial results (I2 = 15.6%; P = .31 for heterogeneity) and the summary OR was 0.70 (95% CI, 0.48-1.01; P = .053) based on the random-effects meta-analysis. The fixed-effect summary OR for the association with mortality was 0.64 (95% CI, 0.50-0.82; P < .001) for dexamethasone compared with usual care or placebo (3 trials, 1282 patients, and 527 deaths), the OR was 0.69 (95% CI, 0.43-1.12; P = .13) for hydrocortisone (3 trials, 374 patients, and 94 deaths), and the OR was 0.91 (95% CI, 0.29-2.87; P = .87) for methylprednisolone (1 trial, 47 patients, and 26 deaths). Among the 6 trials that reported serious adverse events, 64 events occurred among 354 patients randomized to corticosteroids and 80 events occurred among 342 patients randomized to usual care or placebo. Conclusions and Relevance: In this prospective meta-analysis of clinical trials of critically ill patients with COVID-19, administration of systemic corticosteroids, compared with usual care or placebo, was associated with lower 28-day all-cause mortality.

Corticosteroid therapy for critically ill patients with COVID-19: A structured summary of a study protocol for a prospective meta-analysis of randomized trials.

OBJECTIVES: Primary objective: To estimate the effect of corticosteroids compared with usual care or placebo on mortality up to 28 days after randomization. Secondary objectives: To examine whether the effect of corticosteroids compared with usual care or placebo on mortality up to 28 days after randomization varies between subgroups related to treatment characteristics, disease severity at the time of randomization, patient characteristics, or risk of bias. To examine the effect of corticosteroids compared with usual care or placebo on serious adverse events. STUDY DESIGN: Prospective meta-analysis of randomized controlled trials. Both placebo-controlled and open-label trials are eligible. PARTICIPANTS: Hospitalised, critically ill patients with suspected or confirmed COVID-19. INTERVENTION AND COMPARATOR: Intervention groups will have received therapeutic doses of a steroid (dexamethasone, hydrocortisone or methylprednisolone) with IV or oral administration immediately after randomization. The comparator groups will have received standard of care or usual care or placebo. MAIN OUTCOME: All-cause mortality up to 28 days after randomization. SEARCH METHODS: Systematic searching of clinicaltrials.gov , EudraCT, the WHO ISRCTN registry, and the Chinese clinical trials registry. Additionally, research and WHO networks will be asked for relevant trials. RISK OF BIAS ASSESSMENTS: These will be based on the Cochrane RoB 2 tool, and will use structured information provided by the trial investigators on a form designed for this prospective meta-analysis. We will use GRADE to assess the certainty of the evidence. STATISTICAL ANALYSES: Trial investigators will provide data on the numbers of participants who did and did not experience each outcome according to intervention group, overall and in specified subgroups. We will conduct fixed-effect (primary analysis) and random-effects (Paule-Mandel estimate of heterogeneity and Hartung-Knapp adjustment) meta-analyses. We will quantify inconsistency in effects between trials using I2 statistics. Evidence for subgroup effects will be quantified by ratios of odds ratios comparing effects in the subgroups, and corresponding interaction p-values. Comparisons between subgroups defined by trial characteristics will be made using random-effects meta-regression. Comparisons between subgroups defined by patient characteristics will be made by estimating trial-specific ratios of odds ratios comparing intervention effects between subgroups then combining these using random-effects meta-analysis. Steroid interventions will be classified as high or low dose according to whether the dose is greater or less than or equal to 400 mg hydrocortisone per day or equivalent. We will use network meta-analysis methods to make comparisons between the effects of high and low dose steroid interventions (because one trial randomized participants to both low and high dose steroid arms). PROSPERO REGISTRATION NUMBER: CRD42020197242 FULL PROTOCOL: The full protocol for this prospective meta-analysis is attached as an additional file, accessible from the Trials website (Additional file 1). To expedite dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol for the systematic review.

Examining the neural correlates of active and passive forms of verbal-spatial binding in working memory.

We designed an fMRI study to pinpoint the neural correlates of active and passive binding in working memory. Participants were instructed to memorize three words and three spatial locations. In the passive binding condition, words and spatial locations were directly presented as bound. Conversely, in the active binding condition, words and spatial locations were presented as separated, and participants were directed to intentionally create associations between them. Our results showed that participants performed better on passive binding relative to active binding. FMRI analysis revealed that both binding conditions induced greater activity within the hippocampus. Additionally, our analyses divulged regions specifically engaged in passive and active binding. Altogether, these data allow us to propose the hippocampus as a central candidate for working memory binding. When needed, a frontal-parietal network can contribute to the rearrangement of information. These findings may inform theories of working memory binding.

Cellular senescence and protein degradation: breaking down cancer.

Autophagy and the ubiquitin-proteasome pathway (UPP) are the major protein degradation systems in eukaryotic cells. Whereas the former mediate a bulk nonspecific degradation, the UPP allows a rapid degradation of specific proteins. Both systems have been shown to play a role in tumorigenesis, and the interest in developing therapeutic agents inhibiting protein degradation is steadily growing. However, emerging data point to a critical role for autophagy in cellular senescence, an established tumor suppressor mechanism. Recently, a selective protein degradation process mediated by the UPP was also shown to contribute to the senescence phenotype. This process is tightly regulated by E3 ubiquitin ligases, deubiquitinases, and several post-translational modifications of target proteins. Illustrating the complexity of UPP, more than 600 human genes have been shown to encode E3 ubiquitin ligases, a number which exceeds that of the protein kinases. Nevertheless, our knowledge of proteasome-dependent protein degradation as a regulated process in cellular contexts such as cancer and senescence remains very limited. Here we discuss the implications of protein degradation in senescence and attempt to relate this function to the protein degradation pattern observed in cancer cells.

CHES1/FOXN3 regulates cell proliferation by repressing PIM2 and protein biosynthesis.

The expression of the forkhead transcription factor checkpoint suppressor 1 (CHES1), also known as FOXN3, is reduced in many types of cancers. We show here that CHES1 decreases protein synthesis and cell proliferation in tumor cell lines but not in normal fibroblasts. Conversely, short hairpin RNA-mediated depletion of CHES1 increases tumor cell proliferation. Growth suppression depends on the CHES1 forkhead DNA-binding domain and correlates with the nuclear localization of CHES1. CHES1 represses the expression of multiple genes, including the kinases PIM2 and DYRK3, which regulate protein biosynthesis, and a number of genes in cilium biogenesis. CHES1 binds directly to the promoter of PIM2, and in cells expressing CHES1 the levels of PIM2 are reduced, as well as the phosphorylation of the PIM2 target 4EBP1. Overexpression of PIM2 or eIF4E partially reverses the antiproliferative effect of CHES1, indicating that PIM2 and protein biosynthesis are important targets of the antiproliferative effect of CHES1. In several human hematopoietic cancers, CHES1 and PIM2 expressions are inversely correlated, suggesting that repression of PIM2 by CHES1 is clinically relevant.

Tumor suppressor activity of the ERK/MAPK pathway by promoting selective protein degradation.

Constitutive activation of growth factor signaling pathways paradoxically triggers a cell cycle arrest known as cellular senescence. In primary cells expressing oncogenic ras, this mechanism effectively prevents cell transformation. Surprisingly, attenuation of ERK/MAP kinase signaling by genetic inactivation of Erk2, RNAi-mediated knockdown of ERK1 or ERK2, or MEK inhibitors prevented the activation of the senescence mechanism, allowing oncogenic ras to transform primary cells. Mechanistically, ERK-mediated senescence involved the proteasome-dependent degradation of proteins required for cell cycle progression, mitochondrial functions, cell migration, RNA metabolism, and cell signaling. This senescence-associated protein degradation (SAPD) was observed not only in cells expressing ectopic ras, but also in cells that senesced due to short telomeres. Individual RNAi-mediated inactivation of SAPD targets was sufficient to restore senescence in cells transformed by oncogenic ras or trigger senescence in normal cells. Conversely, the anti-senescence viral oncoproteins E1A, E6, and E7 prevented SAPD. In human prostate neoplasms, high levels of phosphorylated ERK were found in benign lesions, correlating with other senescence markers and low levels of STAT3, one of the SAPD targets. We thus identified a mechanism that links aberrant activation of growth signaling pathways and short telomeres to protein degradation and cellular senescence.

Regulation of E2Fs and senescence by PML nuclear bodies.

The tumor suppressor PML (promyelocytic leukemia protein) regulates cellular senescence and terminal differentiation, two processes that implicate a permanent exit from the cell cycle. Here, we show that the mechanism by which PML induces a permanent cell cycle exit and activates p53 and senescence involves a recruitment of E2F transcription factors bound to their promoters and the retinoblastoma (Rb) proteins to PML nuclear bodies enriched in heterochromatin proteins and protein phosphatase 1α. Blocking the functions of the Rb protein family or adding back E2Fs to PML-expressing cells can rescue their defects in E2F-dependent gene expression and cell proliferation, inhibiting the senescent phenotype. In benign prostatic hyperplasia, a neoplastic disease that displays features of senescence, PML was found to be up-regulated and forming nuclear bodies. In contrast, PML bodies were rarely visualized in prostate cancers. The newly defined PML/Rb/E2F pathway may help to distinguish benign tumors from cancers, and suggest E2F target genes as potential targets to induce senescence in human tumors.

Transcriptome analysis and tumor suppressor requirements of STAT5-induced senescence.

Although it is acknowledged that senescent cells accumulate with age, the molecular mechanisms leading to cell senescence as a function of age remain to be identified. In cell culture models, it has been clearly shown that senescence involves the activation of a DNA damage response secondary to short telomeres or oncogene expression. Oncogenes are altered versions of genes coding for proteins that mediate signals from extracellular factors such as cytokines, growth factors, and hormones. In particular, we show here that constitutive activation of the JAK/STAT5 signaling pathway induces senescence in both mouse and human normal cells. The process involves activation of the p53 and Rb tumor suppressor pathways and mitochondrial dysfunction. Gene expression analysis of STAT5-induced senescence revealed changes in the expression of genes coding for cytokines, proteins in cytokine signaling pathways, and several metabolic enzymes. We discuss a model called senescence-induced senescence, in which cytokines secreted by senescent cells can propagate the process as a function of age.

Designing small multiple-target artificial RNAs.

MicroRNAs (miRNAs) are naturally occurring small RNAs that regulate the expression of several genes. MiRNAs' targeting rules are based on sequence complementarity between their mature products and targeted genes' mRNAs. Based on our present understanding of those rules, we developed an algorithm to design artificial miRNAs to target simultaneously a set of predetermined genes. To validate in silico our algorithm, we tested different sets of genes known to be targeted by a single miRNA. The algorithm finds the seed of the corresponding miRNA among the solutions, which also include the seeds of new artificial miRNA sequences potentially capable of targeting these genes as well. We also validated the functionality of some artificial miRNAs designed to target simultaneously members of the E2F family. These artificial miRNAs reproduced the effects of E2Fs inhibition in both normal human fibroblasts and prostate cancer cells where they inhibited cell proliferation and induced cellular senescence. We conclude that the current miRNA targeting rules based on the seed sequence work to design multiple-target artificial miRNAs. This approach may find applications in both research and therapeutics.