SUMOylation controls Hu antigen R posttranscriptional activity in liver cancer.

The posttranslational modification of proteins critically influences many biological processes and is a key mechanism that regulates the function of the RNA-binding protein Hu antigen R (HuR), a hub in liver cancer. Here, we show that HuR is SUMOylated in the tumor sections of patients with hepatocellular carcinoma in contrast to the surrounding tissue, as well as in human cell line and mouse models of the disease. SUMOylation of HuR promotes major cancer hallmarks, namely proliferation and invasion, whereas the absence of HuR SUMOylation results in a senescent phenotype with dysfunctional mitochondria and endoplasmic reticulum. Mechanistically, SUMOylation induces a structural rearrangement of the RNA recognition motifs that modulates HuR binding affinity to its target RNAs, further modifying the transcriptomic profile toward hepatic tumor progression. Overall, SUMOylation constitutes a mechanism of HuR regulation that could be potentially exploited as a therapeutic strategy for liver cancer.

Safety of inhaled nitric oxide withdrawal in severe chronic pulmonary hypertension.

Inhaled nitric oxide (iNO) is a potent and selective pulmonary vasodilator with a safety concern due to rebound pulmonary hypertension (PH) associated with its withdrawal. We report short-term pulsed iNO in patients with severe pulmonary arterial hypertension (PAH) and nonoperable chronic thromboembolic PH (nCTEPH). This is a retrospective analysis of 33 patients: 22 with PAH and 11 with nCTEPH. We assessed hemodynamic, echocardiographic, and other noninvasive variables to evaluate safety and efficacy of iNO. We performed an iNO withdrawal test during right heart catheterization and after 3 days of iNO treatment. iNO significantly improved all variables examined in 22 patients with PAH and 11 with nCTEPH. Two patterns of response were observed after sudden iNO withdrawal. Twenty-nine patients (88%) showed minimal hemodynamic, oxygenation and clinical changes. Four patients (12%) had a reduction in cardiac index ≥20% and PaO2 ≥ 5%, three patients did not show clinical deterioration, and one patient developed hemodynamic collapse that needed iNO administration. This retrospective study suggests that short-term iNO improves hemodynamics and clinical conditions in some patients with PAH an nCTPEH. However, pulsed iNO withdrawal PH rebound could be a serious concern in these patients. Given the lack of evidence, we do not recommend the use of pulsed iNO in the treatment of patients with chronic PH.

Prognosis after heart transplant in patients with hypertrophic and restrictive cardiomyopathy. A nationwide registry analysis.

INTRODUCTION AND OBJECTIVES: Posttransplant outcomes among recipients with a diagnosis of hypertrophic cardiomyopathy (HCM) or restrictive cardiomyopathy (RCM) remain controversial. METHODS: Retrospective analysis of a nationwide registry of first-time recipients undergoing isolated heart transplant between 1984 and 2021. One-year and 5-year mortality in recipients with HCM and RCM were compared with those with dilated cardiomyopathy (DCM). RESULTS: We included 3703 patients (3112 DCM; 331 HCM; 260 RCM) with a median follow-up of 5.0 [3.1-5.0] years. Compared with DCM, the adjusted 1-year mortality risk was: HCM: HR, 1.38; 95%CI, 1.07-1.78; P=.01, RCM: HR, 1.48; 95%CI, 1.14-1.93; P=.003. The adjusted 5-year mortality risk was: HCM: HR, 1.17; 95%CI, 0.93-1.47; P=.18; RCM: HR, 1.52; 95%CI, 1.22-1.89; P<.001. Over the last 20 years, the RCM group showed significant improvement in 1-year survival (adjusted R2=0.95) and 5-year survival (R2=0.88); the HCM group showed enhanced the 5-year survival (R2=0.59), but the 1-year survival remained stable (R2=0.16). CONCLUSIONS: Both RCM and HCM were linked to a less favorable early posttransplant prognosis compared with DCM. However, at the 5-year mark, this unfavorable difference was evident only for RCM. Notably, a substantial temporal enhancement in both early and late mortality was observed for RCM, while for HCM, this improvement was mainly evident in late mortality.

Review of the allocation criteria for heart transplant in Spain in 2023. SEC-Heart Failure Association/ONT/SECCE consensus document.

Heart transplant (HT) remains the best therapeutic option for patients with advanced heart failure (HF). The allocation criteria aim to guarantee equitable access to HT and prioritize patients with a worse clinical status. To review the HT allocation criteria, the Heart Failure Association of the Spanish Society of Cardiology (HFA-SEC), the Spanish Society of Cardiovascular and Endovascular Surgery (SECCE) and the National Transplant Organization (ONT), organized a consensus conference involving adult and pediatric cardiologists, adult and pediatric cardiac surgeons, transplant coordinators from all over Spain, and physicians and nurses from the ONT. The aims of the consensus conference were as follows: a) to analyze the organization and management of patients with advanced HF and cardiogenic shock in Spain; b) to critically review heart allocation and priority criteria in other transplant organizations; c) to analyze the outcomes of patients listed and transplanted before and after the modification of the heart allocation criteria in 2017; and d) to propose new heart allocation criteria in Spain after an analysis of the available evidence and multidisciplinary discussion. In this article, by the HFA-SEC, SECCE and the ONT we present the results of the analysis performed in the consensus conference and the rationale for the new heart allocation criteria in Spain.

Mitochondrial Factors in the Cell Nucleus.

The origin of eukaryotic organisms involved the integration of mitochondria into the ancestor cell, with a massive gene transfer from the original proteobacterium to the host nucleus. Thus, mitochondrial performance relies on a mosaic of nuclear gene products from a variety of genomes. The concerted regulation of their synthesis is necessary for metabolic housekeeping and stress response. This governance involves crosstalk between mitochondrial, cytoplasmic, and nuclear factors. While anterograde and retrograde regulation preserve mitochondrial homeostasis, the mitochondria can modulate a wide set of nuclear genes in response to an extensive variety of conditions, whose response mechanisms often merge. In this review, we summarise how mitochondrial metabolites and proteins-encoded either in the nucleus or in the organelle-target the cell nucleus and exert different actions modulating gene expression and the chromatin state, or even causing DNA fragmentation in response to common stress conditions, such as hypoxia, oxidative stress, unfolded protein stress, and DNA damage.

The Histone Chaperones SET/TAF-1ß and NPM1 Exhibit Conserved Functionality in Nucleosome Remodeling and Histone Eviction in a Cytochrome c-Dependent Manner.

Chromatin homeostasis mediates essential processes in eukaryotes, where histone chaperones have emerged as major regulatory factors during DNA replication, repair, and transcription. The dynamic nature of these processes, however, has severely impeded their characterization at the molecular level. Here, fluorescence optical tweezers are applied to follow histone chaperone dynamics in real time. The molecular action of SET/template-activating factor-Iß and nucleophosmin 1-representing the two most common histone chaperone folds-are examined using both nucleosomes and isolated histones. It is shown that these chaperones present binding specificity for fully dismantled nucleosomes and are able to recognize and disrupt non-native histone-DNA interactions. Furthermore, the histone eviction process and its modulation by cytochrome c are scrutinized. This approach shows that despite the different structures of these chaperones, they present conserved modes of action mediating nucleosome remodeling.

Neddylation of phosphoenolpyruvate carboxykinase 1 controls glucose metabolism.

Neddylation is a post-translational mechanism that adds a ubiquitin-like protein, namely neural precursor cell expressed developmentally downregulated protein 8 (NEDD8). Here, we show that neddylation in mouse liver is modulated by nutrient availability. Inhibition of neddylation in mouse liver reduces gluconeogenic capacity and the hyperglycemic actions of counter-regulatory hormones. Furthermore, people with type 2 diabetes display elevated hepatic neddylation levels. Mechanistically, fasting or caloric restriction of mice leads to neddylation of phosphoenolpyruvate carboxykinase 1 (PCK1) at three lysine residues-K278, K342, and K387. We find that mutating the three PCK1 lysines that are neddylated reduces their gluconeogenic activity rate. Molecular dynamics simulations show that neddylation of PCK1 could re-position two loops surrounding the catalytic center into an open configuration, rendering the catalytic center more accessible. Our study reveals that neddylation of PCK1 provides a finely tuned mechanism of controlling glucose metabolism by linking whole nutrient availability to metabolic homeostasis.

Nicotinamide N-methyltransferase (NNMT) regulates the glucocorticoid signaling pathway during the early phase of adipogenesis.

Obesity is associated with adipose tissue dysfunction through the differentiation and expansion of pre-adipocytes to adipocytes (hyperplasia) and/or increases in size of pre-existing adipocytes (hypertrophy). A cascade of transcriptional events coordinates the differentiation of pre-adipocytes into fully differentiated adipocytes; the process of adipogenesis. Although nicotinamide N-methyltransferase (NNMT) has been associated with obesity, how NNMT is regulated during adipogenesis, and the underlying regulatory mechanisms, remain undefined. In present study we used genetic and pharmacological approaches to elucidate the molecular signals driving NNMT activation and its role during adipogenesis. Firstly, we demonstrated that during the early phase of adipocyte differentiation NNMT is transactivated by CCAAT/Enhancer Binding Protein beta (CEBPB) in response to glucocorticoid (GC) induction. We found that Nnmt knockout, using CRISPR/Cas9 approach, impaired terminal adipogenesis by influencing the timing of cellular commitment and cell cycle exit during mitotic clonal expansion, as demonstrated by cell cycle analysis and RNA sequencing experiments. Biochemical and computational methods showed that a novel small molecule, called CC-410, stably binds to and highly specifically inhibits NNMT. CC-410 was, therefore, used to modulate protein activity during pre-adipocyte differentiation stages, demonstrating that, in line with the genetic approach, chemical inhibition of NNMT at the early stages of adipogenesis impairs terminal differentiation by deregulating the GC network. These congruent results conclusively demonstrate that NNMT is a key component of the GC-CEBP axis during the early stages of adipogenesis and could be a potential therapeutic target for both early-onset obesity and glucocorticoid-induced obesity.

Optimization of Patient Pathway in Heart Failure with Reduced Ejection Fraction and Worsening Heart Failure. Role of Vericiguat.

Heart failure (HF) is a progressive condition with periods of apparent stability and repeated worsening HF events. Over time, unless optimization of HF treatment, worsening HF events become more frequent and patients enter into a cycle of recurrent events with high morbidity and mortality. In patients with HF there is an activation of deleterious neurohormonal pathways, such as the renin angiotensin aldosterone system and the sympathetic system, and an inhibition of protective pathways, including natriuretic peptides and guanylate cyclase. Therefore, HF burden can be reduced only through a holistic approach that targets all neurohormonal systems. In this context, vericiguat may play a key role, as it is the only HF drug that activates the nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate system. On the other hand, it has been described relevant disparities in the management of HF population. Consequently, it is necessary to homogenize the management of these patients, through an integrated patient-care pathway that should be adapted at the local level. In this context, the development of new technologies (ie, video call, specific platforms, remote control devices, etc.) may be very helpful. In this manuscript, a multidisciplinary group of experts analyzed the current evidence and shared their own experience to provide some recommendations about the therapeutic optimization of patients with recent worsening HF, with a particular focus on vericiguat, and also about how the integrated patient-care pathway should be performed.

Invasive management of significant tricuspid regurgitation in clinical practice.

BACKGROUND: Tricuspid regurgitation (TR) is a prevalent condition inside valvular heart disease (VHD) with relevant prognosis implications. However, concordance between real management in clinical practice and invasive treatment recommendations of European Society of Cardiology (ESC) guidelines is unknown. METHODS: A substudy of ESC VHD II survey was performed to evaluate the real treatment of TR compared to the clinical ESC guidelines recommendations published in 2012, 2017 and 2021 was performed. TR cases with surgical indication were divided in 3 groups: 1: severe isolated TR without previous left VHD; 2: moderate/severe TR and concomitant severe left VHD; 3: severe TR plus previous left VHD surgery. RESULTS: Of 902 patients assessed, 123 had significant TR. Fifty (41%) cases demonstrated ESC guidelines 2012-2017 Class I or IIa recommendations for invasive treatment: 9(18%) of group 1, 37(74%) of group 2 and 4(8%) of group 3. Surgery was performed in 24 patients (48%); 1 in group 1(4%), 22 in group 2(92%) and 1 in group 3(4%). Overall concordance was 48% (group 1: 11%; group 2: 59%; group 3: 25%). Regarding the 2021 ESC guidelines only one patient changed groups with an overall concordance of 47% (group 1: 10%; group 2: 59%; group 3: 25%). CONCLUSION: Concordance between 2012, 2017 and 2021 ESC guidelines recommendations and clinical practice for TR surgical intervention is low, especially in those without concomitant severe left VHD. These results suggest the need to improve further guideline implementation and alternative treatments, such as percutaneous, which could resolve potential discrepancies in those clinical scenarios.

Cardiogenic shock code 2023. Expert document for a multidisciplinary organization that allows quality care.

Despite the efforts made to improve the care of cardiogenic shock (CS) patients, including the development of mechanical circulatory support (MCS), the prognosis of these patients continues to be poor. In this context, CS code initiatives arise, based on providing adequate, rapid, and quality care to these patients. In this multidisciplinary document we try to justify the need to implement the SC code, defining its structure/organization, activation criteria, patient flow according to care level, and quality indicators. Our specific purposes are: a) to present the peculiarities of this condition and the lessons of infarction code and previous experiences in CS; b) to detail the structure of the teams, their logistics and the bases for the management of these patients, the choice of the type of MCS, and the moment of its implantation, and c) to address challenges to SC code implementation, including the uniqueness of the pediatric SC code. There is an urgent need to develop protocolized, multidisciplinary, and centralized care in hospitals with a large volume and experience that will minimize inequity in access to the MCS and improve the survival of these patients. Only institutional and structural support from the different administrations will allow optimizing care for CS.

GWAS of genetic factors affecting white blood cell morphological parameters in Sardinians uncovers influence of chromosome 11 innate immunity gene cluster on eosinophil morphology.

Few genome-wide association studies (GWAS) analyzing genetic regulation of morphological traits of white blood cells have been reported. We carried out a GWAS of 12 morphological traits in 869 individuals from the general population of Sardinia, Italy. These traits, included measures of cell volume, conductivity and light scatter in four white-cell populations (eosinophils, lymphocytes, monocytes, neutrophils). This analysis yielded seven statistically significant signals, four of which were novel (four novel, PRG2, P2RX3, two of CDK6). Five signals were replicated in the independent INTERVAL cohort of 11 822 individuals. The most interesting signal with large effect size on eosinophil scatter (P-value = 8.33 x 10-32, beta = -1.651, se = 0.1351) falls within the innate immunity cluster on chromosome 11, and is located in the PRG2 gene. Computational analyses revealed that a rare, Sardinian-specific PRG2:p.Ser148Pro mutation modifies PRG2 amino acid contacts and protein dynamics in a manner that could possibly explain the changes observed in eosinophil morphology. Our discoveries shed light on genetics of morphological traits. For the first time, we describe such large effect size on eosinophils morphology that is relatively frequent in Sardinian population.

Phosphorylation disrupts long-distance electron transport in cytochrome c.

It has been recently shown that electron transfer between mitochondrial cytochrome c and the cytochrome c1 subunit of the cytochrome bc1 can proceed at long-distance through the aqueous solution. Cytochrome c is thought to adjust its activity by changing the affinity for its partners via Tyr48 phosphorylation, but it is unknown how it impacts the nanoscopic environment, interaction forces, and long-range electron transfer. Here, we constrain the orientation and separation between cytochrome c1 and cytochrome c or the phosphomimetic Y48pCMF cytochrome c, and deploy an array of single-molecule, bulk, and computational methods to investigate the molecular mechanism of electron transfer regulation by cytochrome c phosphorylation. We demonstrate that phosphorylation impairs long-range electron transfer, shortens the long-distance charge conduit between the partners, strengthens their interaction, and departs it from equilibrium. These results unveil a nanoscopic view of the interaction between redox protein partners in electron transport chains and its mechanisms of regulation.

Breaking barriers in cardiac donation after circulatory death.

BACKGROUND: Heart transplant (HT) from controlled donation after circulatory death (cDCD) is an emerging strategy that is rapidly expanding and may help increase the heart donor pool. MATERIALS AND METHODS: The use of thoracoabdominal normothermic regional perfusion with extracorporeal membrane oxygenation device has allowed to perform HT after cDCD in our country. We present a successful case of heart transplantation using a graft from cDCD with 201 min cold ischemia time. DISCUSSION AND CONCLUSION: HT from cDCD could be a good alternative to brain dead donation. This experience suggests than nonlocal cardiac from cDCD could tolerate long periods of cold ischemia time and break the main barriers with this technique.

Nucleus-translocated mitochondrial cytochrome c liberates nucleophosmin-sequestered ARF tumor suppressor by changing nucleolar liquid-liquid phase separation.

The regular functioning of the nucleolus and nucleus-mitochondria crosstalk are considered unrelated processes, yet cytochrome c (Cc) migrates to the nucleus and even the nucleolus under stress conditions. Nucleolar liquid-liquid phase separation usually serves the cell as a fast, smart mechanism to control the spatial localization and trafficking of nuclear proteins. Actually, the alternative reading frame (ARF), a tumor suppressor protein sequestered by nucleophosmin (NPM) in the nucleoli, is shifted out from NPM upon DNA damage. DNA damage also triggers early translocation of respiratory Cc to nucleus before cytoplasmic caspase activation. Here, we show that Cc can bind to nucleolar NPM by triggering an extended-to-compact conformational change, driving ARF release. Such a NPM-Cc nucleolar interaction can be extended to a general mechanism for DNA damage in which the lysine-rich regions of Cc-rather than the canonical, arginine-rich stretches of membrane-less organelle components-controls the trafficking and availability of nucleolar proteins.

PP2A is activated by cytochrome c upon formation of a diffuse encounter complex with SET/TAF-Iß.

Intrinsic protein flexibility is of overwhelming relevance for intermolecular recognition and adaptability of highly dynamic ensemble of complexes, and the phenomenon is essential for the understanding of numerous biological processes. These conformational ensembles-encounter complexes-lack a unique organization, which prevents the determination of well-defined high resolution structures. This is the case for complexes involving the oncoprotein SET/template-activating factor-Iß (SET/TAF-Iß), a histone chaperone whose functions and interactions are significantly affected by its intrinsic structural plasticity. Besides its role in chromatin remodeling, SET/TAF-Iß is an inhibitor of protein phosphatase 2A (PP2A), which is a key phosphatase counteracting transcription and signaling events controlling the activity of DNA damage response (DDR) mediators. During DDR, SET/TAF-Iß is sequestered by cytochrome c (Cc) upon migration of the hemeprotein from mitochondria to the cell nucleus. Here, we report that the nuclear SET/TAF-Iß:Cc polyconformational ensemble is able to activate PP2A. In particular, the N-end folded, globular region of SET/TAF-Iß (a.k.a. SET/TAF-Iß ΔC)-which exhibits an unexpected, intrinsically highly dynamic behavior-is sufficient to be recognized by Cc in a diffuse encounter manner. Cc-mediated blocking of PP2A inhibition is deciphered using an integrated structural and computational approach, combining small-angle X-ray scattering, electron paramagnetic resonance, nuclear magnetic resonance, calorimetry and molecular dynamics simulations.

Practical tips for managing FLT3 mutated acute myeloid leukemia with midostaurin.

INTRODUCTION: FLT3 inhibitors have been recently introduced as novel treatment targets in patients with FLT3-mutated acute myeloid leukemia (AML). Midostaurin is an oral multikinase inhibitor that targets multiple receptor tyrosine kinases including FLT3 and has been approved for the treatment of AML with FLT3 mutations in patients candidates for intensive chemotherapy. This article presents an updated overall overview of the use of midostaurin in clinical practice. AREAS COVERED: Tests and examinations to be performed before the use of midostaurin, antifungal and antimicrobial treatment, as well as antifungal and antimicrobial prophylaxis are discussed. Practical tips for the treatment of QTc interval prolongation and heart failure are also presented. EXPERT OPINION: Midostaurin is the first agent showing significant survival benefit when combined with chemotherapy in FLT3-mutated AML patients. Optimal use of midostaurin should be a priority, being essential to know the interactions with other drugs like strong CYP3A4 inhibitors or inducers, which are particularly used in the concomitant treatment of AML patients and may increase toxicity or decrease therapeutic benefit. The active role of hematologists and nursing teams is crucial to ensure patient adherence to midostaurin treatment and to minimize adverse effects by administrating the optimal dose for each situation.

ARL15 modulates magnesium homeostasis through N-glycosylation of CNNMs.

Cyclin M (CNNM1-4) proteins maintain cellular and body magnesium (Mg2+) homeostasis. Using various biochemical approaches, we have identified members of the CNNM family as direct interacting partners of ADP-ribosylation factor-like GTPase 15 (ARL15), a small GTP-binding protein. ARL15 interacts with CNNMs at their carboxyl-terminal conserved cystathionine-ß-synthase (CBS) domains. In silico modeling of the interaction between CNNM2 and ARL15 supports that the small GTPase specifically binds the CBS1 and CNBH domains. Immunocytochemical experiments demonstrate that CNNM2 and ARL15 co-localize in the kidney, with both proteins showing subcellular localization in the endoplasmic reticulum, Golgi apparatus and the plasma membrane. Most importantly, we found that ARL15 is required for forming complex N-glycosylation of CNNMs. Overexpression of ARL15 promotes complex N-glycosylation of CNNM3. Mg2+ uptake experiments with a stable isotope demonstrate that there is a significant increase of 25Mg2+ uptake upon knockdown of ARL15 in multiple kidney cancer cell lines. Altogether, our results establish ARL15 as a novel negative regulator of Mg2+ transport by promoting the complex N-glycosylation of CNNMs.