First two unrelated cases of isolated sedoheptulokinase deficiency: A benign disorder?

We present the first two reported unrelated patients with an isolated sedoheptulokinase (SHPK) deficiency. The first patient presented with neonatal cholestasis, hypoglycemia, and anemia, while the second patient presented with congenital arthrogryposis multiplex, multiple contractures, and dysmorphisms. Both patients had elevated excretion of erythritol and sedoheptulose, and each had a homozygous nonsense mutation in SHPK. SHPK is an enzyme that phosphorylates sedoheptulose to sedoheptulose-7-phosphate, which is an important intermediate of the pentose phosphate pathway. It is questionable whether SHPK deficiency is a causal factor for the clinical phenotypes of our patients. This study illustrates the necessity of extensive functional and clinical workup for interpreting a novel variant, including nonsense variants

Unveiling the powerhouse: ASCL1-driven small cell lung cancer is characterized by higher numbers of mitochondria and enhanced oxidative phosphorylation

Background: Small cell lung cancer (SCLC) is an aggressive malignancy with distinct molecular subtypes defined by transcription factors and inflammatory characteristics. This follow-up study aimed to validate the unique metabolic phenotype in achaete-scute homologue 1 (ASCL1)-driven SCLC cell lines and human tumor tissue. Methods: Metabolic alterations were analyzed using proteomic data. Structural and functional differences of mitochondria were investigated using qPCR, flow cytometry, confocal imaging, and transmission electron microscopy and seahorse assays. Several metabolic inhibitors were tested using MTT-based and clonogenic assays. Single-cell enzyme activity assays were conducted on cell lines and tumor tissue samples of SCLC patients. Results: We found increased mitochondrial numbers correlating with higher oxidative phosphorylation activity in ASCL1-dominant cells compared to other SCLC subtypes. Metabolic inhibitors targeting mitochondrial respiratory complex-I or carnitine palmitoyltransferase 1 revealed higher responsiveness in SCLC-A. Conversely, we demonstrated that non-ASCL1-driven SCLCs with lower oxidative signatures show dependence on glutaminolysis as evidenced by the enhanced susceptibility to glutaminase inhibition. Accordingly, we detected increased glutamate-dehydrogenase activity in non-ASCL1-dominant cell lines as well as in human SCLC tissue samples. Conclusions: Distinct SCLC subtypes exhibit unique metabolic vulnerabilities, suggesting potential for subtype-specific therapies targeting the respiratory chain, fatty acid transport, or glutaminolysis

Imaging of metabolic activity adaptations to UV stress, drugs and differentiation at cellular resolution in skin and skin equivalents – Implications for oxidative UV damage

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Itaconate is a metabolic regulator of bone formation in homeostasis and arthritis

Objectives Bone remodelling is a highly dynamic process dependent on the precise coordination of osteoblasts and haematopoietic-cell derived osteoclasts. Changes in core metabolic pathways during osteoclastogenesis, however, are largely unexplored and it is unknown whether and how these processes are involved in bone homeostasis. Methods We metabolically and transcriptionally profiled cells during osteoclast and osteoblast generation. Individual gene expression was characterised by quantitative PCR and western blot. Osteoblast function was assessed by Alizarin red staining. immunoresponsive gene 1 ( Irg1 ) - deficient mice were used in various inflammatory or non-inflammatory models of bone loss. Tissue gene expression was analysed by RNA in situ hybridisation. Results We show that during differentiation preosteoclasts rearrange their tricarboxylic acid cycle, a process crucially depending on both glucose and glutamine. This rearrangement is characterised by the induction of Irg1 and production of itaconate, which accumulates intracellularly and extracellularly. While the IRG1–itaconate axis is dispensable for osteoclast generation in vitro and in vivo, we demonstrate that itaconate stimulates osteoblasts by accelerating osteogenic differentiation in both human and murine cells. This enhanced osteogenic differentiation is accompanied by reduced proliferation and altered metabolism. Additionally, supplementation of itaconate increases bone formation by boosting osteoblast activity in mice. Conversely, Irg1- deficient mice exhibit decreased bone mass and have reduced osteoproliferative lesions in experimental arthritis. Conclusion In summary, we identify itaconate, generated as a result of the metabolic rewiring during osteoclast differentiation, as a previously unrecognised regulator of osteoblasts.http://dx.doi.org/10.13039/501100006012Christian Doppler Forschungsgesellschafthttp://dx.doi.org/10.13039/501100004955Österreichische Forschungsförderungsgesellschafthttp://dx.doi.org/10.13039/501100001822Österreichischen Akademie der Wissenschaftenhttp://dx.doi.org/10.13039/501100002428Austrian Science Fundhttp://dx.doi.org/10.13039/501100003494Herzfelder'sche Familienstiftun

Sedoheptulose Kinase Regulates Glucose Metabolism And Immune Cell Polarization

Die Regulierung von Makrophagen und des zellulären Metabolismus durch verschiedene Arten von Stress ist noch immer nicht zur Gänze verstanden. In dieser Arbeit haben wir versucht, durch gezieltes testen von rund 200 unterschiedlichen Kinasen, neue Regulationswege aufzuzeigen, die eine mögliche Rolle bei der Makrophage Aktivierung spielen. Dieser Screen hat zur Entdeckung einer Sedoheptulose Kinase geführt, die, wie wir in weiterer Folge zeigen konnten, eine wichtige Funktion im Pentose Phosphate Pathway bzw. Glukose Metabolismus inne hält. Diese Kinase wird während der Makrophagen Aktivierung endogen – transkriptionell sowie post-translational – reguliert. Wir konnten dies im Menschen sowie in Mäusen zeigen. Mittels Gegenregulation durch Überexpression haben wir die Folgen der endogenen Sedoheptulose Kinase Regulation in Makrophagen untersucht. Wir zeigen, dass diese Regulation den Ausgang des Aktivierungsprozesses bestimmt; Makrophagen zeigten eine verminderte NFB Aktivierung, eine mildere Induktion von pro-inflammatorischen Zytokine und keine signifikante Erhöhung von freien Radikalen nach Stimulierung mit bakteriellem Endotoxin. Zusammenfassend haben wir gezeigt, dass eine Sedoheptulose Kinase existiert, die einerseits den zellulären Metabolismus reguliert und andererseits eine fundamentale Rolle in der Immune-Zell-Aktivierung hat. Diese Dualität lässt den Schluss zu, dass metabolische Adaption während der Differenzierung von Makrophagen essentiell ist.Regulation of the innate immune response and the metabolic requirement of cells to deal with environmental stressors is complex and remains poorly understood. Here we screened 199 kinases in endotoxin-stimulated macrophages to identify potential candidates involved in immune regulation. This screen revealed a novel carbohydrate kinase, which we characterized as a mammalian Sedoheptulose kinase (Carkl/Shpk) and as novel regulator of the Pentose Phosphate Pathway. Macrophage activation resulted in Shpk mRNA down-regulation and post-translational modification. This regulation was required to polarize macrophages into effector cells as overexpression of Shpk resulted in improper macrophage activation. Collectively, our data identify the essential function of Shpk in metabolism and for the first time report on an interface fundamental for coordinating bio-energetic adjustments in shaping immune cell function. This functional duality of Shpk underscores the notion that the apparatus involved in the polarization of innate immune cells, is intimately linked to basic cellular metabolism.submitted by Arvand HaschemiAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersZsfassung in dt. SpracheWien, Med. Univ., Diss., 201

Sedoheptulose kinase regulates glucose metabolism and immune cell polarization

Die Regulierung von Makrophagen und des zellulären Metabolismus durch verschiedene Arten von Stress ist noch immer nicht zur Gänze verstanden. In dieser Arbeit haben wir versucht, durch gezieltes testen von rund 200 unterschiedlichen Kinasen, neue Regulationswege aufzuzeigen, die eine mögliche Rolle bei der Makrophage Aktivierung spielen. Dieser Screen hat zur Entdeckung einer Sedoheptulose Kinase geführt, die, wie wir in weiterer Folge zeigen konnten, eine wichtige Funktion im Pentose Phosphate Pathway bzw. Glukose Metabolismus inne hält. Diese Kinase wird während der Makrophagen Aktivierung endogen transkriptionell sowie post-translational reguliert. Wir konnten dies im Menschen sowie in Mäusen zeigen. Mittels Gegenregulation durch Überexpression haben wir die Folgen der endogenen Sedoheptulose Kinase Regulation in Makrophagen untersucht. Wir zeigen, dass diese Regulation den Ausgang des Aktivierungsprozesses bestimmt; Makrophagen zeigten eine verminderte NFB Aktivierung, eine mildere Induktion von pro-inflammatorischen Zytokine und keine signifikante Erhöhung von freien Radikalen nach Stimulierung mit bakteriellem Endotoxin. Zusammenfassend haben wir gezeigt, dass eine Sedoheptulose Kinase existiert, die einerseits den zellulären Metabolismus reguliert und andererseits eine fundamentale Rolle in der Immune-Zell-Aktivierung hat. Diese Dualität lässt den Schluss zu, dass metabolische Adaption während der Differenzierung von Makrophagen essentiell ist.Regulation of the innate immune response and the metabolic requirement of cells to deal with environmental stressors is complex and remains poorly understood. Here we screened 199 kinases in endotoxin-stimulated macrophages to identify potential candidates involved in immune regulation. This screen revealed a novel carbohydrate kinase, which we characterized as a mammalian Sedoheptulose kinase (Carkl/Shpk) and as novel regulator of the Pentose Phosphate Pathway. Macrophage activation resulted in Shpk mRNA down-regulation and post-translational modification. This regulation was required to polarize macrophages into effector cells as overexpression of Shpk resulted in improper macrophage activation. Collectively, our data identify the essential function of Shpk in metabolism and for the first time report on an interface fundamental for coordinating bio-energetic adjustments in shaping immune cell function. This functional duality of Shpk underscores the notion that the apparatus involved in the polarization of innate immune cells, is intimately linked to basic cellular metabolism.submitted by Arvand HaschemiAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersZsfassung in dt. SpracheWien, Med. Univ., Diss., 2010OeBB(VLID)170076

Sedoheptulose kinase regulates cellular carbohydrate metabolism by sedoheptulose 7-phosphate supply

Dynamic carbon re-routing between catabolic and anabolic metabolism is an essential element of cellular transformation associated with tumour formation and immune cell activation. Such bioenergetic adaptations are important for cellular function and therefore require tight control. Carbohydrate phosphorylation has been proposed as a rate-limiting step of several metabolic networks. The recent identification of a sedoheptulose kinase indicated that free sedoheptulose is a relevant and accessible carbon source in humans. Furthermore, the bioavailability of its phosphorylated form, sedoheptulose 7-phosphate, appears to function as a rheostat for carbon-flux at the interface of glycolysis and the pentose phosphate pathway. In the present paper, we review reports of sedoheptulose metabolism, compare it with glucose metabolism, and discuss the regulation of sedoheptulose kinase as mechanism to achieve bioenergetic reprogramming in cells.</jats:p

Haschemi A. Sedoheptulose kinase regulates cellular carbohydrate metabolism by sedoheptulose 7-phosphate supply. Biochem Soc Trans (2013

Abstract Dynamic carbon re-routing between catabolic and anabolic metabolism is an essential element of cellular transformation associated with tumour formation and immune cell activation. Such bioenergetic adaptations are important for cellular function and therefore require tight control. Carbohydrate phosphorylation has been proposed as a rate-limiting step of several metabolic networks. The recent identification of a sedoheptulose kinase indicated that free sedoheptulose is a relevant and accessible carbon source in humans. Furthermore, the bioavailability of its phosphorylated form, sedoheptulose 7-phosphate, appears to function as a rheostat for carbon-flux at the interface of glycolysis and the pentose phosphate pathway. In the present paper, we review reports of sedoheptulose metabolism, compare it with glucose metabolism, and discuss the regulation of sedoheptulose kinase as mechanism to achieve bioenergetic reprogramming in cells