HuR controls glutaminase RNA metabolism.

Glutaminase (GLS) is directly related to cell growth and tumor progression, making it a target for cancer treatment. The RNA-binding protein HuR (encoded by the ELAVL1 gene) influences mRNA stability and alternative splicing. Overexpression of ELAVL1 is common in several cancers, including breast cancer. Here we show that HuR regulates GLS mRNA alternative splicing and isoform translation/stability in breast cancer. Elevated ELAVL1 expression correlates with high levels of the glutaminase isoforms C (GAC) and kidney-type (KGA), which are associated with poor patient prognosis. Knocking down ELAVL1 reduces KGA and increases GAC levels, enhances glutamine anaplerosis into the TCA cycle, and drives cells towards glutamine dependence. Furthermore, we show that combining chemical inhibition of GLS with ELAVL1 silencing synergistically decreases breast cancer cell growth and invasion. These findings suggest that dual inhibition of GLS and HuR offers a therapeutic strategy for breast cancer treatment.

Single-cell resolution characterization of myeloid-derived cell states with implication in cancer outcome.

Tumor-associated myeloid-derived cells (MDCs) significantly impact cancer prognosis and treatment responses due to their remarkable plasticity and tumorigenic behaviors. Here, we integrate single-cell RNA-sequencing data from different cancer types, identifying 29 MDC subpopulations within the tumor microenvironment. Our analysis reveals abnormally expanded MDC subpopulations across various tumors and distinguishes cell states that have often been grouped together, such as TREM2+ and FOLR2+ subpopulations. Using deconvolution approaches, we identify five subpopulations as independent prognostic markers, including states co-expressing TREM2 and PD-1, and FOLR2 and PDL-2. Additionally, TREM2 alone does not reliably predict cancer prognosis, as other TREM2+ macrophages show varied associations with prognosis depending on local cues. Validation in independent cohorts confirms that FOLR2-expressing macrophages correlate with poor clinical outcomes in ovarian and triple-negative breast cancers. This comprehensive MDC atlas offers valuable insights and a foundation for futher analyses, advancing strategies for treating solid cancers.

Inhibition of Crif1 protects fatty acid-induced POMC neuron-like cell-line damage by increasing CPT-1 function.

Hypothalamic proopiomelanocortin (POMC) neurons are sensors of signals that reflect the energy stored in the body. Inducing mild stress in proopiomelanocortin neurons protects them from the damage promoted by the consumption of a high-fat diet, mitigating the development of obesity; however, the cellular mechanisms behind these effects are unknown. Here, we induced mild stress in a proopiomelanocortin neuron cell line by inhibiting Crif1. In proopiomelanocortin neurons exposed to high levels of palmitate, the partial inhibition of Crif1 reverted the defects in mitochondrial respiration and ATP production; this was accompanied by improved mitochondrial fusion/fission cycling. Furthermore, the partial inhibition of Crif1 resulted in increased reactive oxygen species production, increased fatty acid oxidation, and reduced dependency on glucose for mitochondrial respiration. These changes were dependent on the activity of CPT-1. Thus, we identified a CPT-1-dependent metabolic shift toward greater utilization of fatty acids as substrates for respiration as the mechanism behind the protective effect of mild stress against palmitate-induced damage of proopiomelanocortin neurons.NEW & NOTEWORTHY Saturated fats can damage hypothalamic neurons resulting in positive energy balance, and this is mitigated by mild cellular stress; however, the mechanisms behind this protective effect are unknown. Using a proopiomelanocortin cell line, we show that under exposure to a high concentration of palmitate, the partial inhibition of the mitochondrial protein Crif1 results in protection due to a metabolic shift warranted by the increased expression and activity of the mitochondrial fatty acid transporter CPT-1.

Microglial phagolysosome dysfunction and altered neural communication amplify phenotypic severity in Prader-Willi Syndrome with larger deletion.

Prader-Willi Syndrome (PWS) is a rare neurodevelopmental disorder of genetic etiology, characterized by paternal deletion of genes located at chromosome 15 in 70% of cases. Two distinct genetic subtypes of PWS deletions are characterized, where type I (PWS T1) carries four extra haploinsufficient genes compared to type II (PWS T2). PWS T1 individuals display more pronounced physiological and cognitive abnormalities than PWS T2, yet the exact neuropathological mechanisms behind these differences remain unclear. Our study employed postmortem hypothalamic tissues from PWS T1 and T2 individuals, conducting transcriptomic analyses and cell-specific protein profiling in white matter, neurons, and glial cells to unravel the cellular and molecular basis of phenotypic severity in PWS sub-genotypes. In PWS T1, key pathways for cell structure, integrity, and neuronal communication are notably diminished, while glymphatic system activity is heightened compared to PWS T2. The microglial defect in PWS T1 appears to stem from gene haploinsufficiency, as global and myeloid-specific Cyfip1 haploinsufficiency in murine models demonstrated. Our findings emphasize microglial phagolysosome dysfunction and altered neural communication as crucial contributors to the severity of PWS T1's phenotype.

Diving into the proteomic atlas of SARS-CoV-2 infected cells.

The COVID-19 pandemic was initiated by the rapid spread of a SARS-CoV-2 strain. Though mainly classified as a respiratory disease, SARS-CoV-2 infects multiple tissues throughout the human body, leading to a wide range of symptoms in patients. To better understand how SARS-CoV-2 affects the proteome from cells with different ontologies, this work generated an infectome atlas of 9 cell models, including cells from brain, blood, digestive system, and adipocyte tissue. Our data shows that SARS-CoV-2 infection mainly trigger dysregulations on proteins related to cellular structure and energy metabolism. Despite these pivotal processes, heterogeneity of infection was also observed, highlighting many proteins and pathways uniquely dysregulated in one cell type or ontological group. These data have been made searchable online via a tool that will permit future submissions of proteomic data ( https://reisdeoliveira.shinyapps.io/Infectome_App/ ) to enrich and expand this knowledgebase.

In vivo chronic exposure to inorganic mercury worsens hypercholesterolemia, oxidative stress and atherosclerosis in the LDL receptor knockout mice.

Heavy metal exposure leads to multiple system dysfunctions. The mechanisms are likely multifactorial and involve inflammation and oxidative stress. The aim of this study was to evaluate markers and risk factors for atherosclerosis in the LDL receptor knockout mouse model chronically exposed to inorganic mercury (Hg) in the drinking water. Results revealed that Hg exposed mice present increased plasma levels of cholesterol, without alterations in glucose. As a major source and target of oxidants, we evaluated mitochondrial function. We found that liver mitochondria from Hg treated mice show worse respiratory control, lower oxidative phosphorylation efficiency and increased H2O2 release. In addition, Hg induced mitochondrial membrane permeability transition. Erythrocytes from Hg treated mice showed a 50% reduction in their ability to take up oxygen, lower levels of reduced glutathione (GSH) and of antioxidant enzymes (SOD, catalase and GPx). The Hg treatment disturbed immune system cells counting and function. While lymphocytes were reduced, monocytes, eosinophils and neutrophils were increased. Peritoneal macrophages from Hg treated mice showed increased phagocytic activity. Hg exposed mice tissues present metal impregnation and parenchymal architecture alterations. In agreement, increased systemic markers of liver and kidney dysfunction were observed. Plasma, liver and kidney oxidative damage indicators (MDA and carbonyl) were increased while GSH and thiol groups were diminished by Hg exposure. Importantly, atherosclerotic lesion size in the aorta root of Hg exposed mice were larger than in controls. In conclusion, in vivo chronic exposure to Hg worsens the hypercholesterolemia, impairs mitochondrial bioenergetics and redox function, alters immune cells profile and function, causes several tissues oxidative damage and accelerates atherosclerosis development.

A comprehensive SARS-CoV-2 and COVID-19 review, Part 2: host extracellular to systemic effects of SARS-CoV-2 infection.

COVID-19, the disease caused by SARS-CoV-2, has caused significant morbidity and mortality worldwide. The betacoronavirus continues to evolve with global health implications as we race to learn more to curb its transmission, evolution, and sequelae. The focus of this review, the second of a three-part series, is on the biological effects of the SARS-CoV-2 virus on post-acute disease in the context of tissue and organ adaptations and damage. We highlight the current knowledge and describe how virological, animal, and clinical studies have shed light on the mechanisms driving the varied clinical diagnoses and observations of COVID-19 patients. Moreover, we describe how investigations into SARS-CoV-2 effects have informed the understanding of viral pathogenesis and provide innovative pathways for future research on the mechanisms of viral diseases.

Core mitochondrial genes are down-regulated during SARS-CoV-2 infection of rodent and human hosts.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral proteins bind to host mitochondrial proteins, likely inhibiting oxidative phosphorylation (OXPHOS) and stimulating glycolysis. We analyzed mitochondrial gene expression in nasopharyngeal and autopsy tissues from patients with coronavirus disease 2019 (COVID-19). In nasopharyngeal samples with declining viral titers, the virus blocked the transcription of a subset of nuclear DNA (nDNA)-encoded mitochondrial OXPHOS genes, induced the expression of microRNA 2392, activated HIF-1α to induce glycolysis, and activated host immune defenses including the integrated stress response. In autopsy tissues from patients with COVID-19, SARS-CoV-2 was no longer present, and mitochondrial gene transcription had recovered in the lungs. However, nDNA mitochondrial gene expression remained suppressed in autopsy tissue from the heart and, to a lesser extent, kidney, and liver, whereas mitochondrial DNA transcription was induced and host-immune defense pathways were activated. During early SARS-CoV-2 infection of hamsters with peak lung viral load, mitochondrial gene expression in the lung was minimally perturbed but was down-regulated in the cerebellum and up-regulated in the striatum even though no SARS-CoV-2 was detected in the brain. During the mid-phase SARS-CoV-2 infection of mice, mitochondrial gene expression was starting to recover in mouse lungs. These data suggest that when the viral titer first peaks, there is a systemic host response followed by viral suppression of mitochondrial gene transcription and induction of glycolysis leading to the deployment of antiviral immune defenses. Even when the virus was cleared and lung mitochondrial function had recovered, mitochondrial function in the heart, kidney, liver, and lymph nodes remained impaired, potentially leading to severe COVID-19 pathology.

A nitroalkene derivative of salicylate alleviates diet-induced obesity by activating creatine metabolism and non-shivering thermogenesis.

Obesity-related type II diabetes (diabesity) has increased global morbidity and mortality dramatically. Previously, the ancient drug salicylate demonstrated promise for the treatment of type II diabetes, but its clinical use was precluded due to high dose requirements. In this study, we present a nitroalkene derivative of salicylate, 5-(2-nitroethenyl)salicylic acid (SANA), a molecule with unprecedented beneficial effects in diet-induced obesity (DIO). SANA reduces DIO, liver steatosis and insulin resistance at doses up to 40 times lower than salicylate. Mechanistically, SANA stimulated mitochondrial respiration and increased creatine-dependent energy expenditure in adipose tissue. Indeed, depletion of creatine resulted in the loss of SANA action. Moreover, we found that SANA binds to creatine kinases CKMT1/2, and downregulation CKMT1 interferes with the effect of SANA in vivo. Together, these data demonstrate that SANA is a first-in-class activator of creatine-dependent energy expenditure and thermogenesis in adipose tissue and emerges as a candidate for the treatment of diabesity.

Mitochondrial, cell cycle control and neuritogenesis alterations in an iPSC-based neurodevelopmental model for schizophrenia.

Schizophrenia is a severe psychiatric disorder of neurodevelopmental origin that affects around 1% of the world's population. Proteomic studies and other approaches have provided evidence of compromised cellular processes in the disorder, including mitochondrial function. Most of the studies so far have been conducted on postmortem brain tissue from patients, and therefore, do not allow the evaluation of the neurodevelopmental aspect of the disorder. To circumvent that, we studied the mitochondrial and nuclear proteomes of neural stem cells (NSCs) and neurons derived from induced pluripotent stem cells (iPSCs) from schizophrenia patients versus healthy controls to assess possible alterations related to energy metabolism and mitochondrial function during neurodevelopment in the disorder. Our results revealed differentially expressed proteins in pathways related to mitochondrial function, cell cycle control, DNA repair and neuritogenesis and their possible implication in key process of neurodevelopment, such as neuronal differentiation and axonal guidance signaling. Moreover, functional analysis of NSCs revealed alterations in mitochondrial oxygen consumption in schizophrenia-derived cells and a tendency of higher levels of intracellular reactive oxygen species (ROS). Hence, this study shows evidence that alterations in important cellular processes are present during neurodevelopment and could be involved with the establishment of schizophrenia, as well as the phenotypic traits observed in adult patients. Neural stem cells (NSCs) and neurons were derived from induced pluripotent stem cells (iPSCs) from schizophrenia patients and controls. Proteomic analyses were performed on the enriched mitochondrial and nuclear fractions of NSCs and neurons. Whole-cell proteomic analysis was also performed in neurons. Our results revealed alteration in proteins related to mitochondrial function, cell cycle control, among others. We also performed energy pathway analysis and reactive oxygen species (ROS) analysis of NSCs, which revealed alterations in mitochondrial oxygen consumption and a tendency of higher levels of intracellular ROS in schizophrenia-derived cells.

Phenotypic changes in low-density lipoprotein particles as markers of adverse clinical outcomes in COVID-19.

BACKGROUND AND AIMS: Low-density lipoprotein (LDL) plasma concentration decline is a biomarker for acute inflammatory diseases, including coronavirus disease-2019 (COVID-19). Phenotypic changes in LDL during COVID-19 may be equally related to adverse clinical outcomes. METHODS: Individuals hospitalized due to COVID-19 (n = 40) were enrolled. Blood samples were collected on days 0, 2, 4, 6, and 30 (D0, D2, D4, D6, and D30). Oxidized LDL (ox-LDL), and lipoprotein-associated phospholipase A2 (Lp-PLA2) activity were measured. In a consecutive series of cases (n = 13), LDL was isolated by gradient ultracentrifugation from D0 and D6 and was quantified by lipidomic analysis. Association between clinical outcomes and LDL phenotypic changes was investigated. RESULTS: In the first 30 days, 42.5% of participants died due to Covid-19. The serum ox-LDL increased from D0 to D6 (p < 0.005) and decreased at D30. Moreover, individuals who had an ox-LDL increase from D0 to D6 to over the 90th percentile died. The plasma Lp-PLA2 activity also increased progressively from D0 to D30 (p < 0.005), and the change from D0 to D6 in Lp-PLA2 and ox-LDL were positively correlated (r = 0.65, p < 0.0001). An exploratory untargeted lipidomic analysis uncovered 308 individual lipids in isolated LDL particles. Paired-test analysis from D0 and D6 revealed higher concentrations of 32 lipid species during disease progression, mainly represented by lysophosphatidyl choline and phosphatidylinositol. In addition, 69 lipid species were exclusively modulated in the LDL particles from non-survivors as compared to survivors. CONCLUSIONS: Phenotypic changes in LDL particles are associated with disease progression and adverse clinical outcomes in COVID-19 patients and could serve as a potential prognostic biomarker.

Obesity increases blood-brain barrier permeability and aggravates the mouse model of multiple sclerosis.

Obesity-induced insulin resistance (OIR) has been associated with an increased prevalence of neurodegenerative disorders such as multiple sclerosis. Obesity results in increased blood-brain barrier (BBB) permeability, specifically in the hypothalamic regions associated with the control of caloric intake. In obesity, the chronic state of low-grade inflammation has been implicated in several chronic autoimmune inflammatory disorders. However, the mechanisms that connect the inflammatory profile of obesity with the severity of experimental autoimmune encephalomyelitis (EAE) are poorly defined. In this study, we show that obese mice are more susceptible to EAE, presenting a worse clinical score with more severe pathological changes in the spinal cord when compared with control mice. Analysis of immune infiltrates at the peak of the disease shows that high-fat diet (HFD)- and control (chow)-fed groups do not present any difference in innate or adaptive immune cell compartments, indicating the increased severity occurs prior to disease onset. In the setting of worsening EAE in HFD-fed mice, we observed spinal cord lesions in myelinated regions and (blood brain barrier) BBB disruption. We also found higher levels of pro-inflammatory monocytes, macrophages, and IFN-γ+CD4+ T cells in the HFD-fed group compared to chow-fed animals. Altogether, our results indicate that OIR promotes BBB disruption, allowing the infiltration of monocytes/macrophages and activation of resident microglia, ultimately promoting CNS inflammation and exacerbation of EAE.

Immunometabolic Signature during Respiratory Viral Infection: A Potential Target for Host-Directed Therapies.

RNA viruses are known to induce a wide variety of respiratory tract illnesses, from simple colds to the latest coronavirus pandemic, causing effects on public health and the economy worldwide. Influenza virus (IV), parainfluenza virus (PIV), metapneumovirus (MPV), respiratory syncytial virus (RSV), rhinovirus (RhV), and coronavirus (CoV) are some of the most notable RNA viruses. Despite efforts, due to the high mutation rate, there are still no effective and scalable treatments that accompany the rapid emergence of new diseases associated with respiratory RNA viruses. Host-directed therapies have been applied to combat RNA virus infections by interfering with host cell factors that enhance the ability of immune cells to respond against those pathogens. The reprogramming of immune cell metabolism has recently emerged as a central mechanism in orchestrated immunity against respiratory viruses. Therefore, understanding the metabolic signature of immune cells during virus infection may be a promising tool for developing host-directed therapies. In this review, we revisit recent findings on the immunometabolic modulation in response to infection and discuss how these metabolic pathways may be used as targets for new therapies to combat illnesses caused by respiratory RNA viruses.

Tissue-specific metabolic profile drives iNKT cell function during obesity and liver injury.

Invariant natural killer T (iNKT) cells are a distinct population of lymphocytes characterized by their reactivity to glycolipids presented by CD1d. iNKT cells are found throughout the body, and little is known about their tissue-specific metabolic regulation. Here, we show that splenic and hepatic iNKT cells are metabolically comparable and rely on glycolytic metabolism to support their activation. Deletion of the pyruvate kinase M2 (Pkm2) gene in splenic and hepatic iNKT cells impairs their response to specific stimulation and their ability to mitigate acute liver injury. In contrast, adipose tissue (AT) iNKT cells exhibit a distinctive immunometabolic profile, with AMP-activated protein kinase (AMPK) being necessary for their function. AMPK deficiency impairs AT-iNKT physiology, blocking their capacity to maintain AT homeostasis and their ability to regulate AT inflammation during obesity. Our work deepens our understanding on the tissue-specific immunometabolic regulation of iNKT cells, which directly impacts the course of liver injury and obesity-induced inflammation.

SARS-CoV-2 infects adipose tissue in a fat depot- and viral lineage-dependent manner.

Visceral adiposity is a risk factor for severe COVID-19, and a link between adipose tissue infection and disease progression has been proposed. Here we demonstrate that SARS-CoV-2 infects human adipose tissue and undergoes productive infection in fat cells. However, susceptibility to infection and the cellular response depends on the anatomical origin of the cells and the viral lineage. Visceral fat cells express more ACE2 and are more susceptible to SARS-CoV-2 infection than their subcutaneous counterparts. SARS-CoV-2 infection leads to inhibition of lipolysis in subcutaneous fat cells, while in visceral fat cells, it results in higher expression of pro-inflammatory cytokines. Viral load and cellular response are attenuated when visceral fat cells are infected with the SARS-CoV-2 gamma variant. A similar degree of cell death occurs 4-days after SARS-CoV-2 infection, regardless of the cell origin or viral lineage. Hence, SARS-CoV-2 infects human fat cells, replicating and altering cell function and viability in a depot- and viral lineage-dependent fashion.

PD-1/PD-L1 blockade abrogates a dysfunctional innate-adaptive immune axis in critical ß-coronavirus disease.

Severe COVID-19 is associated with hyperinflammation and weak T cell responses against SARS-CoV-2. However, the links between those processes remain partially characterized. Moreover, whether and how therapeutically manipulating T cells may benefit patients are unknown. Our genetic and pharmacological evidence demonstrates that the ion channel TMEM176B inhibited inflammasome activation triggered by SARS-CoV-2 and SARS-CoV-2-related murine ß-coronavirus. Tmem176b-/- mice infected with murine ß-coronavirus developed inflammasome-dependent T cell dysfunction and critical disease, which was controlled by modulating dysfunctional T cells with PD-1 blockers. In critical COVID-19, inflammasome activation correlated with dysfunctional T cells and low monocytic TMEM176B expression, whereas PD-L1 blockade rescued T cell functionality. Here, we mechanistically link T cell dysfunction and inflammation, supporting a cancer immunotherapy to reinforce T cell immunity in critical ß-coronavirus disease.

Impact of Microbiota Depletion by Antibiotics on SARS-CoV-2 Infection of K18-hACE2 Mice.

Clinical and experimental data indicate that severe acute respiratory syndrome coronavirus (SARS-CoV)-2 infection is associated with significant changes in the composition and function of intestinal microbiota. However, the relevance of these effects for SARS-CoV-2 pathophysiology is unknown. In this study, we analyzed the impact of microbiota depletion after antibiotic treatment on the clinical and immunological responses of K18-hACE2 mice to SARS-CoV-2 infection. Mice were treated with a combination of antibiotics (kanamycin, gentamicin, metronidazole, vancomycin, and colistin, Abx) for 3 days, and 24 h later, they were infected with SARS-CoV-2 B lineage. Here, we show that more than 80% of mice succumbed to infection by day 11 post-infection. Treatment with Abx had no impact on mortality. However, Abx-treated mice presented better clinical symptoms, with similar weight loss between infected-treated and non-treated groups. We observed no differences in lung and colon histopathological scores or lung, colon, heart, brain and kidney viral load between groups on day 5 of infection. Despite some minor differences in the expression of antiviral and inflammatory markers in the lungs and colon, no robust change was observed in Abx-treated mice. Together, these findings indicate that microbiota depletion has no impact on SARS-CoV-2 infection in mice.

SARS-CoV-2 infection impacts carbon metabolism and depends on glutamine for replication in Syrian hamster astrocytes.

COVID-19 causes more than million deaths worldwide. Although much is understood about the immunopathogenesis of the lung disease, a lot remains to be known on the neurological impact of COVID-19. Here, we evaluated immunometabolic changes using astrocytes in vitro and dissected brain areas of SARS-CoV-2 infected Syrian hamsters. We show that SARS-CoV-2 alters proteins of carbon metabolism, glycolysis, and synaptic transmission, many of which are altered in neurological diseases. Real-time respirometry evidenced hyperactivation of glycolysis, further confirmed by metabolomics, with intense consumption of glucose, pyruvate, glutamine, and alpha ketoglutarate. Consistent with glutamine reduction, the blockade of glutaminolysis impaired viral replication and inflammatory response in vitro. SARS-CoV-2 was detected in vivo in hippocampus, cortex, and olfactory bulb of intranasally infected animals. Our data evidence an imbalance in important metabolic molecules and neurotransmitters in infected astrocytes. We suggest this may correlate with the neurological impairment observed during COVID-19, as memory loss, confusion, and cognitive impairment.

A comprehensive SARS-CoV-2 and COVID-19 review, Part 1: Intracellular overdrive for SARS-CoV-2 infection.

COVID-19, the disease caused by SARS-CoV-2, has claimed approximately 5 million lives and 257 million cases reported globally. This virus and disease have significantly affected people worldwide, whether directly and/or indirectly, with a virulent pathogen that continues to evolve as we race to learn how to prevent, control, or cure COVID-19. The focus of this review is on the SARS-CoV-2 virus' mechanism of infection and its proclivity at adapting and restructuring the intracellular environment to support viral replication. We highlight current knowledge and how scientific communities with expertize in viral, cellular, and clinical biology have contributed to increase our understanding of SARS-CoV-2, and how these findings may help explain the widely varied clinical observations of COVID-19 patients.