Cdc42 prevents precocious Rho1 activation during cytokinesis in a Pak1-dependent manner.

During cytokinesis, a series of coordinated events partition a dividing cell. Accurate regulation of cytokinesis is essential for proliferation and genome integrity. In fission yeast, these coordinated events ensure that the actomyosin ring and septum start ingressing only after chromosome segregation. How cytokinetic events are coordinated remains unclear. The GTPase Cdc42 promotes recruitment of certain cell wall-building enzymes whereas the GTPase Rho1 activates these enzymes. We show that Cdc42 prevents early Rho1 activation during fission yeast cytokinesis. Using an active Rho probe, we find that although the Rho1 activators Rgf1 and Rgf3 localize to the division site in early anaphase, Rho1 is not activated until late anaphase, just before the onset of ring constriction. We find that loss of Cdc42 activation enables precocious Rho1 activation in early anaphase. Furthermore, we provide functional and genetic evidence that Cdc42-dependent Rho1 inhibition is mediated by the Cdc42 target Pak1 kinase. Our work proposes a mechanism of Rho1 regulation by active Cdc42 to coordinate timely septum formation and cytokinesis fidelity.

Trajectories of Cardiac Function Following Treatment With an Impella Device in Patients With Acute Anterior ST-Elevation Myocardial Infarction.

Background: Left ventricular (LV) unloading via the percutaneous micro-axial Impella pump is increasingly used in patients with anterior ST-segment elevation myocardial infarction (STEMI) and overt cardiogenic shock. In this context, the evolution of cardiac function and dimensions beyond hospital discharge remains uncertain. We aimed to characterize echocardiographic changes over time in patients with acute anterior STEMI treated with an Impella device. Methods: From an ongoing prospective registry, consecutive patients with acute anterior STEMI managed with an Impella device were extracted. Transthoracic echocardiography was performed at index hospitalization and at first outpatient follow-up. Predictors of response, defined as a ≥ 10% absolute increase in left ventricular ejection fraction (LVEF) at follow-up, were sought. Results: A total of 66 patients (89.4% male, aged 64.3 ± 11.6 years) with anterior STEMI were treated with an Impella device in the first 24 hours of hospitalization, from 2014 to 2022. In-hospital mortality was 24%. Major bleeding and vascular complications requiring surgery occurred in 24% and 11% of patients, respectively. At baseline, mean LVEF was 34% ±12%. At follow-up, survivors showed a significant increase in LVEF (P < 0.0001), whereas LV dimensions, diastolic parameters, and measures of right ventricular dimension and function remained stable. Overall, 28 patients had a ≥ 10% absolute increase in LVEF at follow-up. Baseline creatinine was the only significant predictor of response at univariate analysis. Conclusions: Among patients with anterior STEMI requiring mechanical hemodynamic support with an Impella device, the majority of survivors showed a sustained increase in LV function, without evidence of adverse remodelling. This signal warrants further investigation in dedicated trials.

Contexte: La décharge du ventricule gauche (VG) à l'aide de la pompe microaxiale percutanée Impella est de plus en plus employée chez les patients qui présentent un infarctus du myocarde avec élévation du segment ST (STEMI) et un choc cardiogénique manifeste. Dans ce contexte, l'évolution de la fonction et des dimensions cardiaques après le congé de l'hôpital demeure incertaine. Nous avons cherché à caractériser les variations des paramètres échocardiographiques au fil du temps chez les patients ayant subi un STEMI antérieur aigu traités au moyen d'un dispositif Impella. Méthodologie: À partir d'un registre prospectif actif, nous avons extrait les dossiers de patients consécutifs ayant subi un STEMI antérieur aigu et pris en charge au moyen d'un dispositif Impella. Une échocardiographie transthoracique a été effectuée durant l'hospitalisation de référence puis à la première visite de suivi ambulatoire. Les facteurs prédictifs de la réponse, définis comme une augmentation absolue ≥ 10 % de la fraction d'éjection ventriculaire gauche (FEVG) au moment du suivi, ont été recherchés. Résultats: Au total, 66 patients (89,4 % d'hommes, âgés de 64,3 ± 11,6 ans) ayant subi un STEMI antérieur ont été traités au moyen d'un dispositif Impella pendant les 24 premières heures de l'hospitalisation, entre 2014 et 2022. Le taux de mortalité hospitalière était de 24 %. Des hémorragies majeures et des complications vasculaires ayant nécessité une intervention chirurgicale sont survenues chez 24 % et 11 % des patients, respectivement. Au début de l'étude, la FEVG moyenne était de 34 % ± 12 %. Lors du suivi, les survivants affichaient une augmentation significative de la FEVG (p < 0,0001), alors que les dimensions du VG, les paramètres diastoliques et les mesures de la taille et de la fonction du ventricule droit étaient demeurés stables. Globalement, 28 patients affichaient une augmentation absolue de la FEVG ≥ 10 % lors du suivi. D'après l'analyse univariée, la créatininémie initiale était le seul facteur prédictif important de la réponse. Conclusions: Parmi les patients ayant subi un STEMI antérieur nécessitant un support mécanique hémodynamique au moyen d'un dispositif Impella, une augmentation durable de la fonction ventriculaire gauche, sans signe de remodelage indésirable, a été observée chez la majorité des survivants. Ce signal justifie une évaluation plus approfondie dans le cadre d'essais cliniques conçus à cet effet.

Clinical Characteristics of COVID-19 Patients in a Regional Population With Diabetes Mellitus: The ACCREDIT Study.

Objective: To identify clinical and biochemical characteristics associated with 7- & 30-day mortality and intensive care admission amongst diabetes patients admitted with COVID-19. Research Design and Methods: We conducted a cohort study collecting data from medical notes of hospitalised people with diabetes and COVID-19 in 7 hospitals within the Mersey-Cheshire region from 1 January to 30 June 2020. We also explored the impact on inpatient diabetes team resources. Univariate and multivariate logistic regression analyses were performed and optimised by splitting the dataset into a training, test, and validation sets, developing a robust predictive model for the primary outcome. Results: We analyzed data from 1004 diabetes patients (mean age 74.1 (± 12.6) years, predominantly men 60.7%). 45% belonged to the most deprived population quintile in the UK. Median BMI was 27.6 (IQR 23.9-32.4) kg/m2. The primary outcome (7-day mortality) occurred in 24%, increasing to 33% by day 30. Approximately one in ten patients required insulin infusion (9.8%). In univariate analyses, patients with type 2 diabetes had a higher risk of 7-day mortality [p < 0.05, OR 2.52 (1.06, 5.98)]. Patients requiring insulin infusion had a lower risk of death [p = 0.02, OR 0.5 (0.28, 0.9)]. CKD in younger patients (<70 years) had a greater risk of death [OR 2.74 (1.31-5.76)]. BMI, microvascular and macrovascular complications, HbA1c, and random non-fasting blood glucose on admission were not associated with mortality. On multivariate analysis, CRP and age remained associated with the primary outcome [OR 3.44 (2.17, 5.44)] allowing for a validated predictive model for death by day 7. Conclusions: Higher CRP and advanced age were associated with and predictive of death by day 7. However, BMI, presence of diabetes complications, and glycaemic control were not. A high proportion of these patients required insulin infusion warranting increased input from the inpatient diabetes teams.

FOXM1 and Cancer: Faulty Cellular Signaling Derails Homeostasis.

Forkhead box transcription factor, FOXM1 is implicated in several cellular processes such as proliferation, cell cycle progression, cell differentiation, DNA damage repair, tissue homeostasis, angiogenesis, apoptosis, and redox signaling. In addition to being a boon for the normal functioning of a cell, FOXM1 turns out to be a bane by manifesting in several disease scenarios including cancer. It has been given an oncogenic status based on several evidences indicating its role in tumor development and progression. FOXM1 is highly expressed in several cancers and has also been implicated in poor prognosis. A comprehensive understanding of various aspects of this molecule has revealed its role in angiogenesis, invasion, migration, self- renewal and drug resistance. In this review, we attempt to understand various mechanisms underlying FOXM1 gene and protein regulation in cancer including the different signaling pathways, post-transcriptional and post-translational modifications. Identifying crucial molecules associated with these processes can aid in the development of potential pharmacological approaches to curb FOXM1 mediated tumorigenesis.

Thiostrepton degrades mutant p53 by eliciting an autophagic response in SW480 cells.

Mutations in p53 gene are one of the hallmarks of tumor development. Specific targeting of mutant p53 protein has a promising role in cancer therapeutics. Our preliminary observation showed destabilization of mutant p53 protein in SW480, MiaPaCa and MDAMB231 cell lines upon thiostrepton treatment. In order to elucidate the mechanism of thiostrepton triggered mutant p53 degradation, we explored the impact of proteasome inhibition on activation of autophagy. Combined treatment of thiostrepton and cycloheximide/chloroquine prevented the degradation of mutant p53 protein, reinforcing autophagy as the means of mutant p53 destabilization. Our initial studies suggested that mutant p53 degradation post THSP treatment was carried out by BAG3 mediated autophagy, based on the evidence of BAG1 to BAG3 switching. Subsequent interactome analysis performed post thiostrepton treatment revealed an association of p53 with autophagosome complex associated proteins such as BAG3, p62 and HSC70. Reaccumulation of p53 was seen in BAG3 silenced cells treated with thiostrepton, thereby confirming the role of BAG3 in destabilization of this molecule. Further, localization of p53 into the lysosome upon THSP treatment substantiated our findings that mutant p53 was degraded by an autopahgic process.