bims-ainimu 2025-11-02 papers

Issue of 2025–11–02
six papers selected by
Pedro Escoll Guerrero, Institut Pasteur

Int J Biol Macromol. 2025 Oct 28. pii: S0141-8130(25)09170-6. [Epub ahead of print] 148613

A Legionella pneumophila T4SS effector protein (Ravl) triggers mitochondrial fragmentation through phosphoinositide phosphatase activity.

Ruiling Zhang, Meiling Zhang, Xiaoyu Li, Zhifang Lu, Chen Song, Yangchun Du, Chelsy Chesterman, Laura van Staalduinen, Youjun Wang, Hairun Pei, Zongchao Jia, Jimin Zheng.

Upon ingestion by macrophages, Legionella pneumophila hijacks host membrane trafficking by decorating Legionella-containing vacuoles (LCV), thereby escaping lysosomal degradation. L. pneumophila is dependent on the T4SS effector proteins to recruit mitochondria or promote mitochondria association with the LCV, which induces mitochondrial fragmentation and ultimately alters mitochondrial metabolism. However, a T4SS effector protein implicated in mitochondrial recruitment and fragmentation has yet to be identified. Here, we report the crystal structure of RavL, a L. pneumophila T4SS effector protein. The RavL N-terminus has a canonical mitochondrial targeting sequence. We show that RavL localizes to the mitochondrial membrane and induces fragmentation to disrupt mitochondrial function, ultimately triggering apoptosis in THP-1 macrophages. Further biochemical analysis reveals that RavL is a phosphatidylinositol polyphosphate 5-phosphatase that specifically hydrolyzes the D5 phosphate of PtdIns(4)P, which is derived from PtdIns(4,5)P2. Taken together, our study has identified a novel atypical phosphoinositide phosphatase, RavL, which actively exploits phosphoinositide metabolism to disturb mitochondrial function, thereby promoting bacterial infection.

Keywords: Effector protein; Mitochondrial fragmentation; PI phosphatase; Type IV secretion system

DOI: https://doi.org/10.1016/j.ijbiomac.2025.148613

mSystems. 2025 Oct 31. e0061125

Metabolomic profiling of Burkholderia thailandensis infection of airway epithelial cells provides insights into potential therapeutic targets.

Daniel J Hicks, Nicole Aiosa, Anupama Sinha, Olakunle A Jaiyesimi, Steven S Branda, Neha Garg.

Burkholderia pseudomallei, a gram-negative saprophyte that causes melioidosis, has been classified as a potential bioweapon, posing a serious global threat. Metabolic re-wiring, production of virulence effectors, evasion/suppression of host defenses, and modification of host cell functions constitute important mechanisms in the pathogenesis of infection. Elucidating the metabolism during intracellular growth of the pathogen is critical for learning the mechanisms by which infection is accomplished. Currently, the metabolic activities associated with, and potentially mediating, host-pathogen interactions during infection are not well understood, but recent advances in untargeted mass spectrometry-based metabolomics methods are enabling the narrowing of this knowledge gap. Here, we used untargeted metabolomics analysis to identify polar metabolites produced by Burkholderia thailandensis E264 (a surrogate for B. pseudomallei) and airway epithelial cells (the murine cell line LA-4) during the intracellular stage of infection. Pathway analysis of annotated metabolites that differed in abundance in mock-challenged versus B. thailandensis-challenged host cells revealed changes in the activity of a diverse set of metabolic pathways that could be targeted to combat Burkholderia infections. These include pathways that mediate metabolic processes occurring in both the pathogen and host (e.g., polyamine biosynthesis, NAD+ [nicotinamide adenine dinucleotide] metabolism, and the citric acid cycle), as well as several pathogen-specific pathways (peptidoglycan biosynthesis, ornithine lipid production, and quorum sensing-regulated secondary metabolites). The observed shift in the metabolome shows commonalities with other gram-negative pathogens during infection. Our results provide insight into the changes in metabolism associated with Burkholderia infection and reveal several promising targets for therapeutic interventions.IMPORTANCEBurkholderia pseudomallei is the causative agent of infectious disease, namely melioidosis. When inhaled, Burkholderia pseudomallei causes severe respiratory infections. Due to the potential for severe airborne infections, it is classified as a Tier 1 biothreat agent. The intrinsic antibiotic resistance and increased global prevalence necessitate the development of alternative treatments. Infection triggers a metabolic "arms race" between host and pathogen, where both organisms dramatically alter their metabolism to outcompete one another. By studying these changes, one can identify new therapeutic targets for drug discovery and better understand the mechanisms pathogens use to establish and maintain infection. We performed an untargeted metabolomics analysis of murine epithelial cells co-cultured with Burkholderia thailandensis, a surrogate for Burkholderia pseudomallei, to identify the metabolic shifts that occur during intracellular infection. Using these analyses, we propose several pathways and therapeutic interventions to enable pathogen clearance.

Keywords: Burkholderia; HILIC; airway epithelial cells; infection culture metabolomics; melioidosis

DOI: https://doi.org/10.1128/msystems.00611-25

Cells. 2025 Oct 19. pii: 1629. [Epub ahead of print]14(20):

HPV Oncoproteins and Mitochondrial Reprogramming: The Central Role of ROMO1 in Oxidative Stress and Metabolic Shifts.

Eva Tsoneva, Angel Yordanov.

High-risk human papillomaviruses (HPVs), particularly types 16 and 18, drive carcinogenesis by rewiring host metabolism and mitochondrial function. The oncoproteins E5, E6, and E7 collectively induce mitochondrial fragmentation, increase reactive oxygen species (ROS), and promote a metabolic shift from oxidative phosphorylation (OXPHOS) to glycolysis (the Warburg effect). A redox-sensitive mitochondrial protein, Reactive Oxygen Species Modulator 1 (ROMO1), has emerged as a key mediator of these processes. ROMO1 contributes to mitochondrial morphology, regulates ROS homeostasis, and interacts with key stress-response pathways. While ROMO1 is overexpressed in many cancers and correlates with poor prognosis, recent data suggest that HPV-associated cervical lesions exhibit a unique biphasic expression pattern, with high ROMO1 levels in early stages and reduced expression in advanced tumors. The underlying molecular mechanisms remain unclear, but may involve HPV genome integration, NF-κB suppression, or epigenetic silencing. Key mechanisms such as how HPV modulates ROMO1 expression and how this contributes to stage-dependent metabolic vulnerability remain incompletely understood. This review highlights the current understanding of how HPV oncoproteins impact mitochondrial structure and function, emphasizes the role of ROMO1 in this context, and compares findings with other cancer types. Although no ROMO1-targeted therapies currently exist, the protein may serve as a redox-sensitive biomarker and potential vulnerability in HPV-driven tumors. We propose that targeting mitochondrial fragmentation, ROS signaling, or metabolic reprogramming may offer new avenues for therapeutic intervention. Further research is needed to clarify ROMO1's dual role in early vs. late-stage disease and to validate its relevance as a clinical target. Our review fills a gap in the current literature by being the first to systematically explore ROMO1's contribution to HPV-induced mitochondrial dysfunction and metabolic rewiring, and we outline research priorities for future studies.

Keywords: HPV-driven oncogenesis; ROMO1; ROS; high-risk human papillomaviruses

DOI: https://doi.org/10.3390/cells14201629

J Virol. 2025 Oct 29. e0157225

Perturbed pediatric circulating metabolome in mild and severe dengue disease.

Paul S Soma, Rebekah C Gullberg, Barbara Graham, M Nurul Islam, Guillermina Kuan, Angel Balmaseda, Carol D Blair, Barry J Beaty, John T Belisle, Eva Harris, Rushika Perera.

Four billion people are at risk of infection with dengue viruses (DENV), and this burden is rapidly increasing due to geographic expansion of the mosquito vector. Infection with any of the four serotypes of DENV can result in a self-limiting but debilitating febrile illness (DF), and some infections progress to severe disease with hemorrhagic manifestations and shock (dengue hemorrhagic fever/dengue shock syndrome [DHF/DSS]). DENV infection drives the metabolic state of host cells for viral benefit and induces a host-immune response with metabolic implications that link to disease. Here, a dynamic metabolic response to DENV infection and disease was measured in 535 pediatric patients from Nicaragua using liquid chromatography-tandem mass spectrometry. Metabolomic analyses revealed profound disruptions of critical biochemical pathways and metabolites within the circulating metabolome, especially in those with more severe manifestations of dengue disease. A biomarker panel of 28 metabolites was utilized to classify DF versus DHF/DSS with high sensitivity and specificity, equating to a balanced accuracy of 96.88%. Identified metabolites belonged to biochemical pathways of omega-3 and omega-6 fatty acids, sphingolipids, dipeptides, purines, and tryptophan metabolism. Dipeptides emerged as the most critical molecules for severe disease classification. Additionally, a previously reported trend between serotonin and platelets in DHF patients was expanded upon here, revealing a major depletion of serotonin, but not platelets, in DSS patients. In this study, the perturbed metabolome was used for disease state classification and exploration of the biochemistry of severe dengue disease pathology.IMPORTANCEThe international burden of dengue is intensifying, as the number of reported cases in only the first 5 months of 2025 exceeded that of the previous annual high in 2023. The occurrence of deadly severe manifestations of dengue disease will escalate as the total cases rise, and pediatric patients are at greater risk of developing the rapidly progressing severe dengue diseases than adults. Suboptimal vaccines, lack of clinically approved therapeutics, and no methodologies for prognosis of severe disease exacerbate the difficulty of preventative and supportive care. Because human metabolism is rapidly altered due to infection, perturbations in patients' circulating metabolome can be attributed to dengue disease and correlated to severity. This study contributes metabolic biomarkers of dengue disease in pediatric patients from Nicaragua, indicating that metabolic biomarkers are conserved across patients of different ages and geographic and genetic backgrounds. With validation across many cohorts, there is potential to improve diagnostics.

Keywords: biomarker; dengue; fever; hemorrhagic fever; infectious disease; lipidomics; metabolomics; pediatric; serum; severe disease

DOI: https://doi.org/10.1128/jvi.01572-25

Front Immunol. 2025 ;16 1670488

Mitochondrial dysfunction in PRRSV-2-infected macrophages.

Thien-Phong Vu Manh, Alba Frias-De-Diego, Abigail Williams, John Byrne, Chaitawat Sirisereewan, Julie Hicks, Hsiao-Ching Liu, Elisa Crisci.

Introduction: Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most economically devastating viruses for the global swine industry. PRRSV has a known tropism for lung macrophages, where it causes impaired immune responses. This study evaluated the metabolic and immune profiles of primary porcine alveolar macrophages (PAMs) and pulmonary intravascular macrophages (PIMs) infected with different strains of PRRSV-2 isolated from North Carolina (NC) pig herds (NC134, NC18-9-7 referred to as NC174, and NC20-1 referred to as NC144), and VR2232, a PRRSV-2 prototype strain.
Materials and methods: Primary enriched mononuclear phagocytes were infected in vitro with NC134 and NC174, sorted, and processed. The total RNA was used for a transcriptomic approach; additionally, gene expression was further validated using RT-qPCR and NanoString technology. Complementary functional assays with additional NC strains were used to further investigate the mitochondrial and metabolic dysfunction, as well as the oxidative stress induced by PRRSV-2 infection.
Results: PAMs infected with both NC PRRSV-2 strains NC174 and NC134 showed similar transcriptomic profiles during the early stage of infection, with downregulation of genes involved in the oxidative phosphorylation and electron transport chain pathways. PIMs infected with both NC174 and NC134 strains showed limited alteration in the transcriptomic profiles compared to uninfected cells. Genetic reprogramming matched the PRRSV-2-induced mitochondrial impairment observed in functional assays performed using Seahorse technology. Mitochondrial respiration displayed slightly different profiles between PIMs and PAMs infected with the different PRRSV-2 strains, with PAMs showing a more substantial decrease in mitochondrial fitness compared to control cells. When reactive oxygen species (ROS) and nitric oxide (NO) production were evaluated, no differences were observed between PRRSV-2-infected PAMs and PIMs and control cells.
Conclusion: These results provide valuable insights into the pathogenetic mechanism of different NC PRRSV-2 strains by focusing on the alteration in mitochondrial function in lung macrophages during early infection and highlighting differences in lung macrophage responses to distinct PRRSV-2 strains.

Keywords: NanoString; PRRSV-2; macrophages; mitochondrial dysfunction; pig; seahorse technology; transcriptomics

DOI: https://doi.org/10.3389/fimmu.2025.1670488

Antioxidants (Basel). 2025 Sep 24. pii: 1156. [Epub ahead of print]14(10):

Host-Derived Reactive Oxygen Species in the Gut Epithelium: Defence Mechanism and Target of Bacterial Subversion.

Pranaya Kansakar, Subhadeep Gupta, Amirul Islam Mallick, Brendan W Wren, Ezra Aksoy, Abdi Elmi, Ozan Gundogdu.

Host physical, chemical, and immune responses constitute well-established defences against bacterial invasion. Recent studies have highlighted the critical role of cellular mechanisms, particularly the production of reactive oxygen species (ROS) in antibacterial defence. This review focuses on ROS generation by mammalian intestinal epithelial cells (IECs) and investigates whether ROS production is host-driven to eliminate bacteria or manipulated by bacteria to suppress or exploit ROS for enhanced internalisation. We examine the activation mechanisms of the NADPH oxidase (NOX) enzyme complex and the resulting ROS production in IECs, which, unlike professional phagocytes, lack the ability to engulf bacteria. The downstream effects of NOX-mediated ROS signalling are discussed in detail. Additionally, we explore the dynamic interplay between host and pathogen, with particular attention to how bacterial infection may disrupt or hijack host NOX-mediated ROS responses. The review concludes with key experimental considerations and outlines future directions in this evolving field. Overall, we present ROS as a double-edged sword, an essential antimicrobial effector that is also susceptible to bacterial subversion, highlighting its potential as a target in novel antimicrobial strategies.

Keywords: NOX; enteric pathogens; host–pathogen interaction; reactive oxygen species (ROS)

DOI: https://doi.org/10.3390/antiox14101156