The Smc5/6 Core Complex Is a Structure-Specific DNA Binding and Compacting Machine.

The structural organization of chromosomes is a crucial feature that defines the functional state of genes and genomes. The extent of structural changes experienced by genomes of eukaryotic cells can be dramatic and spans several orders of magnitude. At the core of these changes lies a unique group of ATPases-the SMC proteins-that act as major effectors of chromosome behavior in cells. The Smc5/6 proteins play essential roles in the maintenance of genome stability, yet their mode of action is not fully understood. Here we show that the human Smc5/6 complex recognizes unusual DNA configurations and uses the energy of ATP hydrolysis to promote their compaction. Structural analyses reveal subunit interfaces responsible for the functionality of the Smc5/6 complex and how mutations in these regions may lead to chromosome breakage syndromes in humans. Collectively, our results suggest that the Smc5/6 complex promotes genome stability as a DNA micro-compaction machine.

Presence of Activated (Phosphorylated) STAT3 in Radiation Necrosis Following Stereotactic Radiosurgery for Brain Metastases.

Brain radiation necrosis (RN) is a subacute or late adverse event following radiotherapy, involving an exacerbated inflammatory response of the brain tissue. The risk of symptomatic RN associated with stereotactic radiosurgery (SRS) as part of the treatment of brain metastases (BMs) has been a subject of recent investigation. The activation of the signal transducer and activator of transcription 3 (STAT3) was shown in reactive astrocytes (RA) associated with BMs. Given that the pathophysiological mechanisms behind RN are not fully understood, we sought to investigate the role of STAT3 among other inflammatory markers in RN development. A mouse model of RN using clinical LINAC-based SRS was designed to induce brain necrosis with the administration of 50 Gy in a single fraction to the left hemisphere using a circular collimator of 5 mm diameter. Immunohistochemistry and multiplex staining for CD4, CD8, CD68, GFAP, and STAT3 were performed. For validation, eleven patients with BMs treated with SRS who developed symptomatic RN and required surgery were identified to perform staining for CD68, GFAP, and STAT3. In the mouse model, the RN and perinecrotic areas showed significantly higher staining for F4/80+ and GFAP+ cells, with a high infiltration of CD4 and CD8 T-lymphocytes, when compared to the non-irradiated cerebral hemisphere. A high number of GFAP+pSTAT3+ and F4/80+pSTAT3+ cells was found in the RN areas and the rest of the irradiated hemisphere. The analysis of human brain specimens showed that astrocytes and microglia were actively phosphorylating STAT3 in the areas of RN and gliosis. Phosphorylated STAT3 is highly expressed in the microglia and RA pertaining to the areas of brain RN. Targeting STAT3 via inhibition represents a promising strategy to ameliorate symptomatic RN in BM patients undergoing SRS.

Relevant SARS-CoV-2 viremia is associated with COVID-19 severity: Prospective cohort study and validation cohort.

Early kinetics of SARS-CoV-2 viral load (VL) in plasma determined by quantitative reverse-transcription polymerase chain reaction (RT-PCR) was evaluated as a predictor of poor clinical outcome in a prospective study and assessed in a retrospective validation cohort. Prospective observational single-center study including consecutive adult patients hospitalized with COVID-19 between November 2020 and January 2021. Serial plasma samples were obtained until discharge. Quantitative RT-PCR was performed to assess SARS-CoV-2 VL. The main outcomes were in-hospital mortality, admission to the Intensive Care Unit (ICU), and their combination (Poor Outcome). Relevant viremia (RV), established in the prospective study, was assessed in a retrospective cohort including hospitalized COVID-19 patients from April 2021 to May 2022, in which plasma samples were collected according to clinical criteria. Prospective cohort: 57 patients were included. RV was defined as at least a twofold increase in VL within ≤2 days or a VL > 300 copies/ml, in the first week. Patients with RV (N = 14; 24.6%) were more likely to die than those without RV (35.7% vs. 0%), needed ICU admission (57% vs. 0%) or had Poor Outcome (71.4% vs. 0%), (p < 0.001 for the three variables). Retrospective cohort: 326 patients were included, 18.7% presented RV. Patients with RV compared with patients without RV had higher rates of ICU-admission (odds ratio [OR]: 5.6 [95% confidence interval [CI]: 2.1-15.1); p = 0.001), mortality (OR: 13.5 [95% CI: 6.3-28.7]; p < 0.0001) and Poor Outcome (OR: 11.2 [95% CI: 5.8-22]; p < 0.0001). Relevant SARS-CoV-2 viremia in the first week of hospitalization was associated with higher in-hospital mortality, ICU admission, and Poor Outcome. Findings observed in the prospective cohort were confirmed in a larger validation cohort.

IL-6 serum levels predict severity and response to tocilizumab in COVID-19: An observational study.

BACKGROUND: Patients with coronavirus disaese 2019 (COVID-19) can develop a cytokine release syndrome that eventually leads to acute respiratory distress syndrome requiring invasive mechanical ventilation (IMV). Because IL-6 is a relevant cytokine in acute respiratory distress syndrome, the blockade of its receptor with tocilizumab (TCZ) could reduce mortality and/or morbidity in severe COVID-19. OBJECTIVE: We sought to determine whether baseline IL-6 serum levels can predict the need for IMV and the response to TCZ. METHODS: A retrospective observational study was performed in hospitalized patients diagnosed with COVID-19. Clinical information and laboratory findings, including IL-6 levels, were collected approximately 3 and 9 days after admission to be matched with preadministration and postadministration of TCZ. Multivariable logistic and linear regressions and survival analysis were performed depending on outcomes: need for IMV, evolution of arterial oxygen tension/fraction of inspired oxygen ratio, or mortality. RESULTS: One hundred forty-six patients were studied, predominantly males (66%); median age was 63 years. Forty-four patients (30%) required IMV, and 58 patients (40%) received treatment with TCZ. IL-6 levels greater than 30 pg/mL was the best predictor for IMV (odds ratio, 7.1; P < .001). Early administration of TCZ was associated with improvement in oxygenation (arterial oxygen tension/fraction of inspired oxygen ratio) in patients with high IL-6 (P = .048). Patients with high IL-6 not treated with TCZ showed high mortality (hazard ratio, 4.6; P = .003), as well as those with low IL-6 treated with TCZ (hazard ratio, 3.6; P = .016). No relevant serious adverse events were observed in TCZ-treated patients. CONCLUSIONS: Baseline IL-6 greater than 30 pg/mL predicts IMV requirement in patients with COVID-19 and contributes to establish an adequate indication for TCZ administration.

The relative contribution of natural landscapes and human-mediated factors on the connectivity of a noxious invasive weed.

Examining how the landscape may influence gene flow is at the forefront of understanding population differentiation and adaptation. Such understanding is crucial in light of ongoing environmental changes and the elevated risk of ecosystems alteration. In particular, knowledge of how humans may influence population structure is imperative to allow for informed decisions in management and conservation as well as to gain a better understanding of anthropogenic impacts on the interplay between gene flow, genetic drift, and selection. Here, we use genome-wide molecular markers to characterize the population genetic structure and connectivity of Ipomoea purpurea (Convolvulaceae), a noxious invasive weed. We, likewise, assess the interaction between natural and human-driven influences on genetic differentiation among populations. Our analyses find that human population density is an important predictor of pairwise population differentiation, suggesting that the agricultural and/or horticultural trade may be involved in maintaining some level of connectivity across distant agricultural fields. Climatic variation appears as an additional predictor of genetic connectivity in this species. We discuss the implications of these results and highlight future research needed to disentangle the mechanistic processes underlying population connectivity of weeds.

Inferring responses to climate dynamics from historical demography in neotropical forest lizards.

We apply a comparative framework to test for concerted demographic changes in response to climate shifts in the neotropical lowland forests, learning from the past to inform projections of the future. Using reduced genomic (SNP) data from three lizard species codistributed in Amazonia and the Atlantic Forest (Anolis punctatus, Anolis ortonii, and Polychrus marmoratus), we first reconstruct former population history and test for assemblage-level responses to cycles of moisture transport recently implicated in changes of forest distribution during the Late Quaternary. We find support for population shifts within the time frame of inferred precipitation fluctuations (the last 250,000 y) but detect idiosyncratic responses across species and uniformity of within-species responses across forest regions. These results are incongruent with expectations of concerted population expansion in response to increased rainfall and fail to detect out-of-phase demographic syndromes (expansions vs. contractions) across forest regions. Using reduced genomic data to infer species-specific demographical parameters, we then model the plausible spatial distribution of genetic diversity in the Atlantic Forest into future climates (2080) under a medium carbon emission trajectory. The models forecast very distinct trajectories for the lizard species, reflecting unique estimated population densities and dispersal abilities. Ecological and demographic constraints seemingly lead to distinct and asynchronous responses to climatic regimes in the tropics, even among similarly distributed taxa. Incorporating such constraints is key to improve modeling of the distribution of biodiversity in the past and future.

Loss of Nat4 and its associated histone H4 N-terminal acetylation mediates calorie restriction-induced longevity.

Changes in histone modifications are an attractive model through which environmental signals, such as diet, could be integrated in the cell for regulating its lifespan. However, evidence linking dietary interventions with specific alterations in histone modifications that subsequently affect lifespan remains elusive. We show here that deletion of histone N-alpha-terminal acetyltransferase Nat4 and loss of its associated H4 N-terminal acetylation (N-acH4) extend yeast replicative lifespan. Notably, nat4Δ-induced longevity is epistatic to the effects of calorie restriction (CR). Consistent with this, (i) Nat4 expression is downregulated and the levels of N-acH4 within chromatin are reduced upon CR, (ii) constitutive expression of Nat4 and maintenance of N-acH4 levels reduces the extension of lifespan mediated by CR, and (iii) transcriptome analysis indicates that nat4Δ largely mimics the effects of CR, especially in the induction of stress-response genes. We further show that nicotinamidase Pnc1, which is typically upregulated under CR, is required for nat4Δ-mediated longevity. Collectively, these findings establish histone N-acH4 as a regulator of cellular lifespan that links CR to increased stress resistance and longevity.

Natural and Anthropogenic Influences on the Mating System of the Common Morning Glory.

Evolutionary biologists remain puzzled by the often dramatic variation of mating strategies within single species. Of particular interest is the extent to which environmental conditions shape patterns of variation of mating system components within mixed mating species, and how widespread anthropogenic manipulations may influence these associations. Here, we address this question in the common morning glory (Ipomoea purpurea) by combining a dataset of floral traits, estimates of the mating system, and relevant environmental factors compiled for 22 populations of this species distributed along a wide range of environments from the Southeastern and Midwestern United States. We identify a disparate set of environmental factors to influence population-level variation in selfing, inbreeding, and flower morphology. Although floral traits are primarily associated with climatic variation, the outcrossing rate and inbreeding coefficient are primarily influenced by the level of herbicide resistance. Furthermore, we find that populations with higher levels of herbicide resistance exhibit a stronger correlation between mating system-floral traits and mating system estimates (outcrossing rate and inbreeding coefficient). Altogether, these results demonstrate the dominant role that herbicide application plays in the determination of I. purpurea's mating system, and more generally uncover the complex and unforeseen evolutionary consequences of anthropogenic manipulations in natural systems.

Comment on Rieux and Balloux: calibration from tip-dating can compromise topological accuracy and evolutionary inference.

We contribute to the recent review of Rieux & Balloux, 2016, Mol. Ecol., 25, 1911 on inferences from tip-dated phylogenies by developing their discussion on the influence of population size (Ne ) under panmixia for the estimation of substitution rate (µ). We highlight how phylogenetic trees inferred with tip-dated sequences under large panmictic Ne tend to erroneously enforce an age-based coalescent pattern on the posterior distribution of trees, which in turn results in systematically inflated estimates of µ. We discuss the consequences of this and suggest how to accommodate the issue in the short term and long term.

Predicting the genetic consequences of future climate change: The power of coupling spatial demography, the coalescent, and historical landscape changes.

PREMISE OF THE STUDY: Climate change is a widely accepted threat to biodiversity. Species distribution models (SDMs) are used to forecast whether and how species distributions may track these changes. Yet, SDMs generally fail to account for genetic and demographic processes, limiting population-level inferences. We still do not understand how predicted environmental shifts will impact the spatial distribution of genetic diversity within taxa. METHODS: We propose a novel method that predicts spatially explicit genetic and demographic landscapes of populations under future climatic conditions. We use carefully parameterized SDMs as estimates of the spatial distribution of suitable habitats and landscape dispersal permeability under present-day, past, and future conditions. We use empirical genetic data and approximate Bayesian computation to estimate unknown demographic parameters. Finally, we employ these parameters to simulate realistic and complex models of responses to future environmental shifts. We contrast parameterized models under current and future landscapes to quantify the expected magnitude of change. KEY RESULTS: We implement this framework on neutral genetic data available from Penstemon deustus. Our results predict that future climate change will result in geographically widespread declines in genetic diversity in this species. The extent of reduction will heavily depend on the continuity of population networks and deme sizes. CONCLUSIONS: To our knowledge, this is the first study to provide spatially explicit predictions of within-species genetic diversity using climatic, demographic, and genetic data. Our approach accounts for climatic, geographic, and biological complexity. This framework is promising for understanding evolutionary consequences of climate change, and guiding conservation planning.

Urbanization shapes the demographic history of a native rodent (the white-footed mouse, Peromyscus leucopus) in New York City.

How urbanization shapes population genomic diversity and evolution of urban wildlife is largely unexplored. We investigated the impact of urbanization on white-footed mice,Peromyscus leucopus,in the New York City (NYC) metropolitan area using coalescent-based simulations to infer demographic history from the site-frequency spectrum. We assigned individuals to evolutionary clusters and then inferred recent divergence times, population size changes and migration using genome-wide single nucleotide polymorphisms genotyped in 23 populations sampled along an urban-to-rural gradient. Both prehistoric climatic events and recent urbanization impacted these populations. Our modelling indicates that post-glacial sea-level rise led to isolation of mainland and Long Island populations. These models also indicate that several urban parks represent recently isolated P. leucopus populations, and the estimated divergence times for these populations are consistent with the history of urbanization in NYC.

N-alpha-terminal acetylation of histone H4 regulates arginine methylation and ribosomal DNA silencing.

Post-translational modifications of histones play a key role in DNA-based processes, like transcription, by modulating chromatin structure. N-terminal acetylation is unique among the numerous histone modifications because it is deposited on the N-alpha amino group of the first residue instead of the side-chain of amino acids. The function of this modification and its interplay with other internal histone marks has not been previously addressed. Here, we identified N-terminal acetylation of H4 (N-acH4) as a novel regulator of arginine methylation and chromatin silencing in Saccharomyces cerevisiae. Lack of the H4 N-alpha acetyltransferase (Nat4) activity results specifically in increased deposition of asymmetric dimethylation of histone H4 arginine 3 (H4R3me2a) and in enhanced ribosomal-DNA silencing. Consistent with this, H4 N-terminal acetylation impairs the activity of the Hmt1 methyltransferase towards H4R3 in vitro. Furthermore, combinatorial loss of N-acH4 with internal histone acetylation at lysines 5, 8 and 12 has a synergistic induction of H4R3me2a deposition and rDNA silencing that leads to a severe growth defect. This defect is completely rescued by mutating arginine 3 to lysine (H4R3K), suggesting that abnormal deposition of a single histone modification, H4R3me2a, can impact on cell growth. Notably, the cross-talk between N-acH4 and H4R3me2a, which regulates rDNA silencing, is induced under calorie restriction conditions. Collectively, these findings unveil a molecular and biological function for H4 N-terminal acetylation, identify its interplay with internal histone modifications, and provide general mechanistic implications for N-alpha-terminal acetylation, one of the most common protein modifications in eukaryotes.

Model misspecification confounds the estimation of rates and exaggerates their time dependency.

While welcoming the comment of Ho et al. (2015), we find little that undermines the strength of our criticism, and it would appear they have misunderstood our central argument. Here we respond with the purpose of reiterating that we are (i) generally critical of much of the evidence presented in support of the time-dependent molecular rate (TDMR) hypothesis and (ii) specifically critical of estimates of µ derived from tip-dated sequences that exaggerate the importance of purifying selection as an explanation for TDMR over extended timescales. In response to assertions put forward by Ho et al. (2015), we use panmictic coalescent simulations of temporal data to explore a fundamental assumption for tip-dated tree shape and associated mutation rate estimates, and the appropriateness and utility of the date randomization test. The results reveal problems for the joint estimation of tree topology, effective population size and µ with tip-dated sequences using BEAST. Given the simulations, BEAST consistently obtains incorrect topological tree structures that are consistent with the substantial overestimation of µ and underestimation of effective population size. Data generated from lower effective population sizes were less likely to fail the date randomization test yet still resulted in substantially upwardly biased estimates of rates, bringing previous estimates of µ from temporally sampled DNA sequences into question. We find that our general criticisms of both the hypothesis of time-dependent molecular evolution and Bayesian methods to estimate µ from temporally sampled DNA sequences are further reinforced.

Epithelial to mesenchymal transition and cancer stem cell phenotypes leading to liver metastasis are abrogated by the novel TGFß1-targeting peptides P17 and P144.

Colorectal cancer (CRC) frequently metastasizes to the liver, a phenomenon that involves the participation of transforming-growth-factor-ß(1) (TGFß(1)). Blockade of the protumorigenic effects elicited by TGFß(1) in advanced CRC could attenuate liver metastasis. We aimed in the present study to assess the antimetastatic effect of TGFß(1)-blocking peptides P17 and P144, and to study mechanisms responsible for this activity in a mouse model. Colon adenocarcinoma cells expressing luciferase were pretreated with TGFß(1) (Mc38-luc(TGFß1) cells), injected into the spleen of mice and monitored for tumor development. TGFß(1) increased primary tumor growth and liver metastasis, whereas systemic treatment of mice with either P17 or P144 significantly reduced tumor burden (p<0.01). In metastatic nodules, mitotic/apoptotic ratio, mesenchymal traits and angiogenesis (evaluated by CD-31, as well as circulating endothelial and progenitor cells) induced by TGFß(1) were consistently reduced following injection of peptides. In vitro experiments revealed a direct effect of TGFß(1) in Mc38 cells, which resulted in activation of Smad2, Smad3 and Smad1/5/8, and increased invasion and transendothelial migration, whereas blockade of TGFß(1)-signaling reverted these features. Because TGFß(1)-mediated epithelial-mesenchymal transition (EMT) has been suggested to induce a cancer stem cell (CSC) phenotype, we analyzed the ability of this cytokine to induce tumorsphere formation and the expression of CSC markers. In TGFß(1)-treated cells, tumorspheres were enriched in CD44 and SOX2, which were diminished in the presence of P17. Our data provide a preclinical rationale to evaluate P17 and P144 as potential therapeutic options for the treatment of metastatic CRC.

Plant-based proteins from agro-industrial waste and by-products: Towards a more circular economy.

There is a pressing need for affordable, abundant, and sustainable sources of proteins to address the rising nutrient demands of a growing global population. The food and agriculture sectors produce significant quantities of waste and by-products during the growing, harvesting, storing, transporting, and processing of raw materials. These waste and by-products can sometimes be converted into valuable protein-rich ingredients with excellent functional and nutritional attributes, thereby contributing to a more circular economy. This review critically assesses the potential for agro-industrial wastes and by-products to contribute to global protein requirements. Initially, we discuss the origins and molecular characteristics of plant proteins derived from agro-industrial waste and by-products. We then discuss the techno-functional attributes, extraction methods, and modification techniques that are applied to these plant proteins. Finally, challenges linked to the safety, allergenicity, anti-nutritional factors, digestibility, and sensory attributes of plant proteins derived from these sources are highlighted. The utilization of agro-industrial by-products and wastes as an economical, abundant, and sustainable protein source could contribute towards achieving the Sustainable Development Agenda's 2030 goal of a "zero hunger world", as well as mitigating fluctuations in food availability and prices, which have detrimental impacts on global food security and nutrition.

Localized versus generalist phenotypes in a broadly distributed tropical mammal: how is intraspecific variation distributed across disparate environments?

BACKGROUND: The extent of phenotypic differentiation in response to local environmental conditions is a key component of species adaptation and persistence. Understanding the structuring of phenotypic diversity in response to local environmental pressures can provide important insights into species evolutionary dynamics and responses to environmental change. This work examines the influence of steep environmental gradients on intraspecific phenotypic variation and tests two hypotheses about how the tropical soft grass mouse, Akodon mollis (Cricetidae, Rodentia), contends with the disparate environmental conditions encompassed by its broad distribution. Specifically, we test if the species expresses a geographically unstructured, or generalist, phenotype throughout its range or if it shows geographically localized morphological differentiation across disparate environments. RESULTS: Using geometric morphometric and ecomorphological analyses of skull shape variation we found that despite distinct environmental conditions, geographically structured morphological variation is limited, with the notable exception of a distinct morphological disjunction at the high-elevation forest-grassland transition in the southern portion of A. mollis distribution. Based on genetic analyses, geographic isolation alone does not explain this localized phenotype, given that similar levels of genetic differentiation were also observed among individuals inhabiting other ecosystems that are nonetheless not distinct morphologically. CONCLUSIONS: Instead of phenotypic specialization across environments in these tropical mountains, there was limited differentiation of skull shape and size across the broad range of A. mollis, with the exception of individuals from the puna, the highest-elevation ecosystem. The high morphological variance among individuals, together with a weak association with local environmental conditions, not only highlights the flexibility of A. mollis' skull, but also highlights the need for further study to understand what maintains the observed morphological patterns. The work also indicates that mechanisms other than processes linked to local ecological specialization as a driver of diversification may contribute to the high diversity of this tropical region.

Involvement of the chloroplastic isoform of tRNA ligase in the replication of viroids belonging to the family Avsunviroidae.

Avocado sunblotch viroid, peach latent mosaic viroid, chrysanthemum chlorotic mottle viroid, and eggplant latent viroid (ELVd), the four recognized members of the family Avsunviroidae, replicate through the symmetric pathway of an RNA-to-RNA rolling-circle mechanism in chloroplasts of infected cells. Viroid oligomeric transcripts of both polarities contain embedded hammerhead ribozymes that, during replication, mediate their self-cleavage to monomeric-length RNAs with 5'-hydroxyl and 2',3'-phosphodiester termini that are subsequently circularized. We report that a recombinant version of the chloroplastic isoform of the tRNA ligase from eggplant (Solanum melongena L.) efficiently catalyzes in vitro circularization of the plus [(+)] and minus [(-)] monomeric linear replication intermediates from the four Avsunviroidae. We also show that while this RNA ligase specifically recognizes the genuine monomeric linear (+) ELVd replication intermediate, it does not do so with five other monomeric linear (+) ELVd RNAs with their ends mapping at different sites along the molecule, despite containing the same 5'-hydroxyl and 2',3'-phosphodiester terminal groups. Moreover, experiments involving transient expression of a dimeric (+) ELVd transcript in Nicotiana benthamiana Domin plants preinoculated with a tobacco rattle virus-derived vector to induce silencing of the plant endogenous tRNA ligase show a significant reduction of ELVd circularization. In contrast, circularization of a viroid replicating in the nucleus occurring through a different pathway is unaffected. Together, these results support the conclusion that the chloroplastic isoform of the plant tRNA ligase is the host enzyme mediating circularization of both (+) and (-) monomeric linear intermediates during replication of the viroids belonging to the family Avsunviroidae.

Cross-talk among epigenetic modifications: lessons from histone arginine methylation.

Epigenetic modifications, including those occurring on DNA and on histone proteins, control gene expression by establishing and maintaining different chromatin states. In recent years, it has become apparent that epigenetic modifications do not function alone, but work together in various combinations, and cross-regulate each other in a manner that diversifies their functional states. Arginine methylation is one of the numerous PTMs (post-translational modifications) occurring on histones, catalysed by a family of PRMTs (protein arginine methyltransferases). This modification is involved in the regulation of the epigenome largely by controlling the recruitment of effector molecules to chromatin. Histone arginine methylation associates with both active and repressed chromatin states depending on the residue involved and the configuration of the deposited methyl groups. The present review focuses on the increasing number of cross-talks between histone arginine methylation and other epigenetic modifications, and describe how these cross-talks influence factor binding to regulate transcription. Furthermore, we present models of general cross-talk mechanisms that emerge from the examples of histone arginine methylation and allude to various techniques that help decipher the interplay among epigenetic modifications.

Pleuropulmonary and diaphragmatic ultrasound in intensive care medicine.

The usefulness of ultrasound for chest exploration was described in 1968. It was not until the 1990s, when its use became widespread in Intensive Care Units as a diagnostic, monitoring and procedural guide tool. The fact that it is a non-invasive tool, accessible at the bedside, with a sensitivity and specificity close to computerized tomography (CT) and with a short learning curve, have made it a mandatory technique in the management of critically ill patients. It is essential to know that there are different air/fluid ratio generated by different pathologies that gives rise to one echographic pattern or another. The identification of these patterns together with the clinical information will allow to make an accurate diagnosis in most settings of respiratory failure. Likewise, we must not forget the importance of evaluating diaphragmatic function by ultrasound during weaning from mechanical ventilation.

Cancer Cell-Intrinsic Alterations Associated with an Immunosuppressive Tumor Microenvironment and Resistance to Immunotherapy in Lung Cancer.

Despite the great clinical success of immunotherapy in lung cancer patients, only a small percentage of them (<40%) will benefit from this therapy alone or combined with other strategies. Cancer cell-intrinsic and cell-extrinsic mechanisms have been associated with a lack of response to immunotherapy. The present study is focused on cancer cell-intrinsic genetic, epigenetic, transcriptomic and metabolic alterations that reshape the tumor microenvironment (TME) and determine response or refractoriness to immune checkpoint inhibitors (ICIs). Mutations in KRAS, SKT11(LKB1), KEAP1 and TP53 and co-mutations of these genes are the main determinants of ICI response in non-small-cell lung cancer (NSCLC) patients. Recent insights into metabolic changes in cancer cells that impose restrictions on cytotoxic T cells and the efficacy of ICIs indicate that targeting such metabolic restrictions may favor therapeutic responses. Other emerging pathways for therapeutic interventions include epigenetic modulators and DNA damage repair (DDR) pathways, especially in small-cell lung cancer (SCLC). Therefore, the many potential pathways for enhancing the effect of ICIs suggest that, in a few years, we will have much more personalized medicine for lung cancer patients treated with immunotherapy. Such strategies could include vaccines and chimeric antigen receptor (CAR) cells.