bims-mignad 2024-12-15 papers

Issue of 2024–12–15
five papers selected by
Melisa Emel Ermert, Amsterdam UMC

Blood Adv. 2024 Dec 11. pii: bloodadvances.2024013425. [Epub ahead of print]

NAD+ METABOLISM RESTRICTION BOOSTS HIGH-DOSE MELPHALAN EFFICACY IN PATIENTS WITH MULTIPLE MYELOMA.

Elevated levels of the nicotinamide adenine dinucleotide (NAD+)-generating enzyme nicotinamide phosphoribosyltransferase (NAMPT) are a common feature across numerous cancer types. Accordingly, we previously reported pervasive NAD+ dysregulation in Multiple Myeloma (MM) cells in association with upregulated NAMPT expression. Unfortunately, albeit being effective in preclinical models of cancer, NAMPT inhibition has proven ineffective in clinical trials due to the existence of alternative NAD+ production routes utilizing NAD+ precursors other than nicotinamide. Here, by leveraging mathematical modelling approaches integrated with transcriptome data, we defined the specific NAD+ landscape of MM cells and established that the Preiss-Handler pathway for NAD+-biosynthesis, which utilizes nicotinic acid as a precursor, supports NAD+ synthesis in MM cells via its key enzyme nicotinate phosphoribosyltransferase (NAPRT). Accordingly, we found that NAPRT confers resistance to NAD+ -depleting agents. Transcriptomic, metabolic, and bioenergetic profiling of NAPRT knock-out (KO) MM cells showed these to have weakened endogenous antioxidant defenses, increased propensity to oxidative stress, and enhanced genomic instability. Concomitant NAMPT inhibition further compounded the effects of NAPRT KO, effectively sensitizing MM cells to the chemotherapeutic drug, melphalan; NAPRT added-back fully rescues these phenotypes. Overall, our results propose comprehensive NAD+ biosynthesis inhibition, through simultaneously targeting NAMPT and NAPRT, as a promising strategy to be tested in randomized clinical trials involving transplant-eligible MM patients, especially those with more aggressive disease.

DOI: https://doi.org/10.1182/bloodadvances.2024013425

Front Aging Neurosci. 2024 ;16 1503336

Urolithin A and nicotinamide riboside differentially regulate innate immune defenses and metabolism in human microglial cells.

Helena Borland Madsen, Claudia Navarro, Emilie Gasparini, Jae-Hyeon Park, Zhiquan Li, Deborah L Croteau, Vilhelm A Bohr.

Introduction: During aging, many cellular processes, such as autophagic clearance, DNA repair, mitochondrial health, metabolism, nicotinamide adenine dinucleotide (NAD+) levels, and immunological responses, become compromised. Urolithin A (UA) and Nicotinamide Riboside (NR) are two naturally occurring compounds known for their anti-inflammatory and mitochondrial protective properties, yet the effects of these natural substances on microglia cells have not been thoroughly investigated. As both UA and NR are considered safe dietary supplements, it is equally important to understand their function in normal cells and in disease states.
Methods: This study investigates the effects of UA and NR on immune signaling, mitochondrial function, and microglial activity in a human microglial cell line (HMC3).
Results: Both UA and NR were shown to reduce DNA damage-induced cellular senescence. However, they differentially regulated gene expression related to neuroinflammation, with UA enhancing cGAS-STING pathway activation and NR displaying broader anti-inflammatory effects. Furthermore, UA and NR differently influenced mitochondrial dynamics, with both compounds improving mitochondrial respiration but exhibiting distinct effects on production of reactive oxygen species and glycolytic function.
Discussion: These findings underscore the potential of UA and NR as therapeutic agents in managing neuroinflammation and mitochondrial dysfunction in neurodegenerative diseases.

Keywords: aging; innate immune signaling; microglia; mitochondrial health; nicotinamide riboside; urolithin A

DOI: https://doi.org/10.3389/fnagi.2024.1503336

Cell Death Differ. 2024 Dec 07.

Lactate dehydrogenase B noncanonically promotes ferroptosis defense in KRAS-driven lung cancer.

Liang Zhao, Haibin Deng, Jingyi Zhang, Nicola Zamboni, Haitang Yang, Yanyun Gao, Zhang Yang, Duo Xu, Haiqing Zhong, Geert van Geest, Rémy Bruggmann, Qinghua Zhou, Ralph A Schmid, Thomas M Marti, Patrick Dorn, Ren-Wang Peng.

Ferroptosis is an oxidative, non-apoptotic cell death frequently inactivated in cancer, but the underlying mechanisms in oncogene-specific tumors remain poorly understood. Here, we discover that lactate dehydrogenase (LDH) B, but not the closely related LDHA, subunits of active LDH with a known function in glycolysis, noncanonically promotes ferroptosis defense in KRAS-driven lung cancer. Using murine models and human-derived tumor cell lines, we show that LDHB silencing impairs glutathione (GSH) levels and sensitizes cancer cells to blockade of either GSH biosynthesis or utilization by unleashing KRAS-specific, ferroptosis-catalyzed metabolic synthetic lethality, culminating in increased glutamine metabolism, oxidative phosphorylation (OXPHOS) and mitochondrial reactive oxygen species (mitoROS). We further show that LDHB suppression upregulates STAT1, a negative regulator of SLC7A11, thereby reducing SLC7A11-dependent GSH metabolism. Our study uncovers a previously undefined mechanism of ferroptosis resistance involving LDH isoenzymes and provides a novel rationale for exploiting oncogene-specific ferroptosis susceptibility to treat KRAS-driven lung cancer.

DOI: https://doi.org/10.1038/s41418-024-01427-x

Cell Death Dis. 2024 Dec 06. 15(12): 884

Conjugated fatty acids drive ferroptosis through chaperone-mediated autophagic degradation of GPX4 by targeting mitochondria.

Yusuke Hirata, Yuto Yamada, Soma Taguchi, Ryota Kojima, Haruka Masumoto, Shinnosuke Kimura, Takuya Niijima, Takashi Toyama, Ryoji Kise, Emiko Sato, Yasunori Uchida, Junya Ito, Kiyotaka Nakagawa, Tomohiko Taguchi, Asuka Inoue, Yoshiro Saito, Takuya Noguchi, Atsushi Matsuzawa.

Conjugated fatty acids (CFAs) have been known for their anti-tumor activity. However, the mechanism of action remains unclear. Here, we identify CFAs as inducers of glutathione peroxidase 4 (GPX4) degradation through chaperone-mediated autophagy (CMA). CFAs, such as (10E,12Z)-octadecadienoic acid and α-eleostearic acid (ESA), induced GPX4 degradation, generation of mitochondrial reactive oxygen species (ROS) and lipid peroxides, and ultimately ferroptosis in cancer cell lines, including HT1080 and A549 cells, which were suppressed by either pharmacological blockade of CMA or genetic deletion of LAMP2A, a crucial molecule for CMA. Mitochondrial ROS were sufficient and necessary for CMA-dependent GPX4 degradation. Oral administration of an ESA-rich oil attenuated xenograft tumor growth of wild-type, but not that of LAMP2A-deficient HT1080 cells, accompanied by increased lipid peroxidation, GPX4 degradation and cell death. Our study establishes mitochondria as the key target of CFAs to trigger lipid peroxidation and GPX4 degradation, providing insight into ferroptosis-based cancer therapy.

DOI: https://doi.org/10.1038/s41419-024-07237-w

Metab Eng. 2024 Dec 04. pii: S1096-7176(24)00164-2. [Epub ahead of print]88 25-39

Deciphering molecular drivers of lactate metabolic shift in mammalian cell cultures.

Mauro Torres, Ellie Hawke, Robyn Hoare, Rachel Scholey, Leon P Pybus, Alison Young, Andrew Hayes, Alan J Dickson.

Lactate metabolism plays a critical role in mammalian cell bioprocessing, influencing cellular performance and productivity. The transition from lactate production to consumption, known as lactate metabolic shift, is highly beneficial and has been shown to extend culture lifespan and enhance productivity, yet its molecular drivers remain poorly understood. Here, we have explored the mechanisms that underpin this metabolic shift through two case studies, illustrating environmental- and genetic-driven factors. We characterised these study cases at process, metabolic and transcriptomic levels. Our findings indicate that glutamine depletion coincided with the timing of the lactate metabolic shift, significantly affecting cell growth, productivity and overall metabolism. Transcriptome analysis revealed dynamic regulation the ATF4 pathway, involved in the amino acid (starvation) response, where glutamine depletion activates ATF4 gene and its targets. Manipulating ATF4 expression through overexpression and knockdown experiments showed significant changes in metabolism of glutamine and lactate, impacting cellular performance. Overexpression of ATF4 increased cell growth and glutamine consumption, promoting a lactate metabolic shift. In contrast, ATF4 downregulation decreased cell proliferation and glutamine uptake, leading to production of lactate without any signs of lactate shift. These findings underscore a critical role for ATF4 in regulation of glutamine and lactate metabolism, related to phasic patterns of growth during CHO cell culture. This study offers unique insight into metabolic reprogramming during the lactate metabolic shift and the molecular drivers that determine cell status during culture.

Keywords: Biopharmaceuticals; CHO cells; Glutamine; Lactate metabolic shift; Metabolome; Transcriptome

DOI: https://doi.org/10.1016/j.ymben.2024.12.001