Publications by authors named "Fajas L"

The physical connection between mitochondria and endoplasmic reticulum (ER) is an essential signaling hub to ensure organelle and cellular functions. In skeletal muscle, ER-mitochondria calcium (Ca) signaling is crucial to maintain cellular homeostasis during physical activity. High expression of BCL2L13, a member of the BCL-2 family, was suggested as an adaptive response in endurance-trained human subjects.

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Metabolic reprogramming is considered as a hallmark of cancer and is clinically exploited as a novel target for therapy. The E2F transcription factor-1 (E2F1) regulates various cellular processes, including proliferative and metabolic pathways, and acts, depending on the cellular and molecular context, as an oncogene or tumor suppressor. The latter is evident by the observation that E2f1-knockout mice develop spontaneous tumors, including uterine sarcomas.

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CDK4, along with its regulatory subunit, cyclin D, drives the transition from G1 to S phase, during which DNA replication and metabolic activation occur. In this canonical pathway, CDK4 is essentially a transcriptional regulator that acts through phosphorylation of retinoblastoma protein (RB) and subsequent activation of the transcription factor E2F, ultimately triggering the expression of genes involved in DNA synthesis and cell cycle progression to S phase. In this review, we focus on the newly reported functions of CDK4, which go beyond direct regulation of the cell cycle.

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Unlabelled: The loss of pancreatic β-cell identity has emerged as an important feature of type 2 diabetes development, but the molecular mechanisms are still elusive. Here, we explore the cell-autonomous role of the cell-cycle regulator and transcription factor E2F1 in the maintenance of β-cell identity, insulin secretion, and glucose homeostasis. We show that the β-cell-specific loss of E2f1 function in mice triggers glucose intolerance associated with defective insulin secretion, altered endocrine cell mass, downregulation of many β-cell genes, and concomitant increase of non-β-cell markers.

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  • - During severe liver injury, biliary epithelial cells (BECs) rapidly activate and proliferate to contribute to a regenerative process called ductular reaction (DR), crucial for liver recovery.
  • - Research shows that BECs collect lipids when exposed to a high-fat diet or fatty acids, causing metabolic changes that help convert mature cholangiocytes into reactive BECs.
  • - This lipid overload triggers E2F transcription factors in BECs, promoting cell cycle progression and glycolytic metabolism, highlighting new links between fat metabolism, cellular regeneration, and stem cell behavior in early stages of non-alcoholic fatty liver disease (NAFLD).
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Uterine serous carcinoma (USC) is an aggressive form of endometrial cancer (EC), characterized by its high propensity for metastases. In fact, while endometrioid endometrial carcinoma (EEC), which accounts for 85% of EC, presents a good prognosis, USC is the most frequently fatal. Herein, we used for the first time a peptide-based tyrosine-kinase-activity profiling approach to quantify the changes in tyrosine kinase activation between USC and EEC.

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  • Mitochondria play a dual role in regulating steroid hormone synthesis, and sex hormones further influence mitochondrial function, which is key to maintaining cellular balance and managing inflammation.
  • The study focuses on Nod-like receptor X1 (NLRX1), a receptor associated with mitochondria that helps to modify metabolic functions and reduce inflammation, showing differing effects in female and male mice during infections.
  • Results indicated that NLRX1 reduced inflammation in female macrophages but not in males, highlighting sex-specific responses in immune and metabolic functions, which could help explain observed differences in disease outcomes between sexes.
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Cells have metabolic flexibility that allows them to adapt to changes in substrate availability. Two highly relevant metabolites are glucose and fatty acids (FA), and hence, glycolysis and fatty acid oxidation (FAO) are key metabolic pathways leading to energy production. Both pathways affect each other, and in the absence of one substrate, metabolic flexibility allows cells to maintain sufficient energy production.

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In the past decade, cell cycle regulators have extended their canonical role in cell cycle progression to the regulation of various cellular processes, including cellular metabolism. The regulation of metabolism is intimately connected with the function of autophagy, a catabolic process that promotes the efficient recycling of endogenous components from both extrinsic stress, e.g.

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Growing evidence supports the importance of the p53 tumor suppressor in metabolism but the mechanisms underlying p53-mediated control of metabolism remain poorly understood. Here, we identify the multifunctional E4F1 protein as a key regulator of p53 metabolic functions in adipocytes. While E4F1 expression is upregulated during obesity, E4f1 inactivation in mouse adipose tissue results in a lean phenotype associated with insulin resistance and protection against induced obesity.

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  • * Understanding this coordination is essential for grasping various diseases and physiological processes.
  • * The review emphasizes recent findings on how cell cycle regulators influence metabolic enzymes, the endolysosomal pathway, and mitochondrial functions.
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KRAS mutant lung adenocarcinomas remain intractable for targeted therapies. Genetic interrogation of KRAS downstream effectors, including the MAPK pathway and the interphase CDKs, identified CDK4 and RAF1 as the only targets whose genetic inactivation induces therapeutic responses without causing unacceptable toxicities. Concomitant CDK4 inactivation and RAF1 ablation prevented tumor progression and induced complete regression in 25% of KRAS/p53-driven advanced lung tumors, yet a significant percentage of those tumors that underwent partial regression retained a population of CDK4/RAF1-resistant cells.

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This study investigated the role of CDK4 in the oxidative metabolism of brown adipose tissue (BAT). BAT from Cdk4 mice exhibited fewer lipids and increased mitochondrial volume and expression of canonical thermogenic genes, rendering these mice more resistant to cold exposure. Interestingly, these effects were not BAT cell-autonomous but rather driven by increased sympathetic innervation.

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Cyclin-dependent kinases (CDKs) are emerging regulators of adipose tissue metabolism. Here we aimed to explore the role of CDK7 in thermogenic fat. We found that CDK7 brown adipose tissue (BAT)-specific knockout mice (Cdk7) have decreased BAT mass and impaired β3-adrenergic signaling and develop hypothermia upon cold exposure.

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Memory CD8 T cells can provide long-term protection against tumors, which depends on their enhanced proliferative capacity, self-renewal and unique metabolic rewiring to sustain cellular fitness. Specifically, memory CD8 T cells engage oxidative phosphorylation and fatty acid oxidation to fulfill their metabolic demands. In contrast, tumor-infiltrating lymphocytes (TILs) display severe metabolic defects, which may underlie their functional decline.

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Cancer proliferation and progression involves altered metabolic pathways as a result of continuous demand for energy and nutrients. In the last years, cell cycle regulators have been involved in the control of metabolic processes, such as glucose and insulin pathways and lipid synthesis, in addition to their canonical function controlling cell cycle progression. Here we describe recent data demonstrating the role of cell cycle regulators in the metabolic control especially in studies performed in cancer models.

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Unlabelled: Protein phosphorylation--catalyzed by protein kinases-is the most common post-translational modification. It increases the functional diversity of the proteome and influences various aspects of normal physiology and can be altered in disease states. High throughput profiling of kinases is becoming an essential experimental approach to investigate their activity and this can be achieved using technologies such as PamChip® arrays provided by PamGene for kinase activity measurement.

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Article Synopsis
  • Interactions between metabolic organs and the central nervous system are essential for maintaining energy balance and adapting to the environment, but these processes can be disrupted in conditions like obesity and type 2 diabetes.
  • Bioactive peptides and proteins, including hormones and cytokines, play a crucial role in communication between these organs, influencing how the body manages energy.
  • Recent research has enhanced our understanding of these interactions, paving the way for new therapeutic approaches aimed at promoting health and combating metabolic diseases.
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  • CDK4 is traditionally known for its role in the cell cycle, but this study reveals its significant involvement in cancer metabolism and mTORC1 signaling through its effects on lysosomes.
  • The research shows that CDK4 phosphorylates the tumor suppressor folliculin, which is crucial for mTORC1 activation on lysosomes, and that inhibiting CDK4 leads to lysosomal dysfunction, triggering cancer cell senescence.
  • By using a combination of CDK4 inhibitors and AMPK activators, the study proposes a new therapeutic approach that enhances autophagy and induces cancer cell death, offering an innovative strategy for cancer treatment.
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Introduction: Adipose tissue is considered an important metabolic tissue, in charge of energy storage as well as being able to act in systemic homeostasis and inflammation. Epigenetics involves a series of factors that are important for gene regulation or for chromatin structure, mostly DNA methylation and histone-tail modifications, which can be modified by environmental conditions (nutrition, lifestyle, smoking…). Since metabolic diseases like obesity and diabetes are closely related to lifestyle and nutrition, epigenetic deregulation could play an important role in the onset of these diseases and vice versa.

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Cyclin-dependent kinase 4 (CDK4) is a positive regulator of cell cycle progression, however, there is growing evidence demonstrating that its function exceeds the control of cell division. Here we show that CDK4 is an important regulator of cellular substrate utilization through direct inhibition of the metabolic regulator AMPK (AMP-activated protein kinase).

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  • β-Klotho is a crucial co-receptor for FGF15 and FGF21, and mice lacking Klb show increased bile acid production and a disrupted metabolic response to these growth factors.
  • Male Klb mice exhibit restricted growth and minimal changes in carbohydrate metabolism, maintaining normal glucose tolerance while showing increased gluconeogenesis and decreased glycogen breakdown.
  • The livers of Klb mice display inflammation, early fibrosis, and a significant alteration in bile acid composition, linked to excess deoxycholic acid that poses genotoxic risks to the gastrointestinal system, highlighting β-Klotho's role in maintaining liver health.
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