Biology subjects

Brenner, D.

Publications and source records attributed to Brenner, D..

18 recordsLinked to original sources

bioRxiv2026

Simultaneous broad protection against Ebola Sudan, Marburg and Lassa viruses conferred by a DNA primed MVA-vectored multivalent vaccine

Sub-Saharan Africa continues to experience recurrent outbreaks of zoonotic viral diseases that spill over unpredictably from animal reservoirs into human populations. In many regions, mpox co-circulates with viral hemorrhagic fevers (VHFs) caused by Ebola Sudan virus (SUDV), Marburg virus (MARV), and Lassa fever virus (LASV). Overlapping clinical syndromes that these VHF cause challenge surveillance, diagnostics and timely deployment of effective countermeasures. A single vaccine capable of protecting against these biologically and genetically distinct pathogens would markedly reduce the cost and complexity of outbreak response, lessen dependence on emergency international aid, and strengthen long-term health system resilience. Here, we report on the development of an MVA-based mpox vaccine engineered to express computationally designed, broad-coverage antigens targeting SUDV, MARV and LASV. In preclinical challenge studies, this multivalent vaccine elicited robust immune responses and conferred significant protection against lethal infection from all three pathogens in parallel challenge experiments. These findings establish preclinical proof-of-concept for a single, broadly protective VHF vaccine and support its clinical development for deployment across diverse settings in Sub-Saharan Africa. SignificanceOutbreak control in Sub-Saharan Africa is challenged by the co-circulation of different high consequence human infections such as mpox and diverse viral hemorrhagic fevers (VHF) such as SUDV, MARV, and LASV pathogens. These VHFs have overlapping early clinical syndromes, complicating triage and delaying effective targeted interventions. We developed a single MVA-based vaccine encoding computationally designed, conserved antigens from all three VHFs encoded within the MVA vector analogous to the licensed mpox vaccine. In simultaneous challenge models, this multivalent vaccine elicited robust humoral and cellular responses and conferred significant protection against lethal infection by each hemorrhagic fever pathogen. This work provides preclinical proof-of-concept for a unified, broadly protective countermeasure compatible with existing MVA-mpox vaccine manufacturing and deployment experience. By reducing dependence on rapid differential diagnostics and streamlining logistics relative to maintaining multiple pathogen-specific vaccine stockpiles, this approach can lower costs, accelerate response, and increase equity of access during syndromic outbreaks. The platforms engineered antigen breadth and human safety profile of MVA together support a pragmatic translational pathway toward clinical evaluation and regional readiness for zoonotic spillover events that are intensifying with human and environmental changes.

immunology↗

bioRxiv2026

A Translational Model of MASLD-Associated HFpEF Defines Mitochondrial Dysfunction and Cardiac Plasticity During Disease Progression and Regression

Metabolic dysfunction-associated steatotic liver disease (MASLD) and its progressive form, metabolic dysfunction-associated steatohepatitis (MASH), are strongly linked to cardiac dysfunction, particularly, heart failure with preserved ejection fraction (HFpEF), yet the mechanisms underlying this association remain unclear because robust integrative preclinical models are lacking and the liver and heart are rarely studied as a coordinated system. Here we show that Alms1-/- (Foz/Foz) mice fed a Western diet develop MASH with advanced liver fibrosis accompanied by a HFpEF-like phenotype characterized by left ventricular hypertrophy, impaired cardiomyocyte contractility, reduced {beta}-adrenergic reserve, elevated BNP, and increased mortality despite ejection fraction >50%. Liver fibrosis emerged as a parameter strongly associated with the cardiac dysfunction. Remarkably, dietary reversal improved hepatic architecture, normalized cardiac function, and improved survival, revealing marked plasticity of the liver-heart axis. Analyses of left ventricular (LV) remodeling revealed mitochondrial dysfunction, altered substrate utilization, and extracellular matrix remodeling in the LV, with consistent concordance to human HFpEF transcriptomic signatures. Ultrastructural studies confirmed mitochondrial injury and sarcomeric disorganization, linking metabolic failure to impaired cardiomyocyte performance. Together, these findings identify mitochondrial dysfunction as an important feature of MASLD-associated HFpEF-like cardiac dysfunction and establish the Foz/Foz model as a powerful platform for investigating pathophysiological pathways linking metabolic liver disease to cardiac dysfunction and for testing mechanism-based therapeutic strategies. STRUCTURED ABSTRACTO_ST_ABSBackgroundC_ST_ABSMetabolic dysfunction associated steatotic liver disease (MASLD) and its advanced form, MASH, are closely linked to cardiac dysfunction, particularly heart failure with preserved ejection fraction (HFpEF). However, the mechanisms underlying MASLD-associated HFpEF and its reversibility remain poorly understood, largely due to the lack of robust preclinical models. Here, we established a translational model of MASLD-associated cardiac dysfunction that recapitulates the key features of human HFpEF. We applied functional and transcriptomic analyses of the left ventricle (LV) to define the pathways associated with cardiac dysfunction and its reversibility. MethodsAlms1-/- (Foz/Foz) mice and wild-type littermates were fed normal chow (NC) or Western diet (WD) for up to 36 weeks (wk). Reversibility was modeled by switching WD-fed Foz/Foz mice at 12wk back to NC for 12wk. Cardiac assessment included echocardiography, invasive hemodynamics with dobutamine stimulation, histopathology, electron microscopy and isolated cardiomyocyte contractility. LV transcriptomes were profiled by bulk RNA sequencing and analyzed by differential expression and pathway enrichment. ResultsFoz/Foz mice on WD for 24wk developed metabolic syndrome and MASH with advanced liver fibrosis. Cardiac phenotyping showed LV hypertrophy, impaired cardiomyocyte contractility, reduced {beta}-adrenergic reserve, elevated plasma BNP, and increased mortality while the ejection fraction was preserved (>50%), consistent with HFpEF. The progression of cardiac dysfunction was closely associated with liver fibrosis that developed during MASH. Switching WD-fed Foz/Foz mice at 12wk to normal chow diet reversed hepatic fibrosis, restored LV function, and reduced mortality, demonstrating plasticity of the liver-heart axis. LV transcriptomic analysis revealed that cardiac impairment in these mice was associated with mitochondrial dysfunction, altered substrate utilization, extracellular matrix remodeling, and metabolic stress; pathways that are similarly dysregulated in human HFpEF. Cardiac electron microscopy revealed swollen mitochondria with disrupted cristae, which improved following dietary intervention. ConclusionsMitochondrial dysfunction and fibroinflammatory remodeling are prominent features of MASLD-associated cardiac dysfunction. Reversal of hepatic and cardiac phenotypes with dietary intervention, together with elucidation of underlying pathways, establish the Foz/Foz model as a useful translational platform for studying liver-heart axis in MASLD. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/708088v2_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@60bd2aorg.highwire.dtl.DTLVardef@1234a09org.highwire.dtl.DTLVardef@1d1c5aborg.highwire.dtl.DTLVardef@1086089_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2025

Variability in cadmium accumulation in quinoa grain: potential role of crop domestication and other factors mediating differences in resilience and uptake

Quinoa (Chenopodium quinoa) is a nutritious crop expanding in importance worldwide, though its capacity to accumulate cadmium (Cd) can put consumers at risk. The objective of this study was to identify genotypes that vary in Cd uptake and explore how domestication, saponins, and root-associated microbes could influence these differences. Twelve genotypes representing wild ancestors and modern landraces or cultivars from four distinct ecoregions were grown in a greenhouse trial using potting media amended with Cd. Differences in phenological developmental traits were recorded during growth, and plant biomass, microbial derived amino sugars in roots, and concentrations of Cd and other essential elements in grains were quantified at harvest. Phenological development of Ancestors were more adversely affected by Cd than modern genotypes, and Cd concentrations were higher in those developed later near coastal regions in South America and the United States, suggesting that quinoa become more tolerant over domestication and selection. Concentrations of several elements were also lower in the Ancestors vs. modern genotypes in response to Cd, indicating that modern genotypes may not downregulate root transporters as an adaptation to Cd stress. Fungal derived amino sugars were negatively correlated with Cd concentrations in the Coastal ecotypes which had the highest uptake, suggesting that the presence of root-associated fungi could help restrict translocation aboveground. Results of this study will provide breeders with new insights into factors that could aid in selecting for quinoa with low Cd-uptake. Early genotypes selected in the Altiplano region may be most useful in these breeding programs.

plant biology↗

bioRxiv2025

A single-cell fixed RNA profiling of liver fibrosis progression and regression reveals SEMA4D and LMCD1 as key mediators of fibrogenesis

Liver fibrosis progression and regression are dynamic processes involving diverse hepatic and immune cell populations. Here, we utilize single-cell fixed RNA profiling (FLEX) of a TAA-induced mouse liver cirrhosis model, with and without a recovery phase, to depict the cellular landscape and molecular mechanisms of fibrosis resolution. The regression phase was characterized by the emergence of pericentral hepatocytes enriched in detoxification and antioxidant genes (e.g., Cyp2e1, Txn1), which secreted Rarres2 to modulate hepatic stellate cell (HSC) function. This was accompanied by the upregulation of scar-resolving genes (Mmp14, Ctsl), restoration of fenestrae in liver sinusoidal endothelial cells, anti-inflammatory phenotypes of Kupffer cells, a decrease in fibrogenic cholangiocyte subsets, and recovery-associated signatures in NK/T cells, B cells, and neutrophils. In contrast, SEMA4D secreted by monocyte-derived macrophages during fibrosis progression activated Plxnb2 HSCs, and its blockade attenuated fibrosis in vivo. Furthermore, LMCD1 was identified as a novel marker for HSC activation and regulation. This single-cell atlas reveals key transcriptional programs and intercellular signaling pathways dependent on the fibrotic condition, offering new therapeutic targets for liver cirrhosis.

cell biology↗

bioRxiv2025

D-Lactate drives cytotoxicity in Th1 cells by limiting mitochondrial ROS production through enhanced glyoxalase system activity

CD4+ T lymphocytes with cytotoxic activity are an understudied T helper (Th) cell population with the capacity to orchestrate immune responses and kill target cells in a TCR-restricted manner. Particularly, the mechanisms that promote the differentiation of cytotoxic Th cells remain elusive. Here, by supplementing Th1 cells with different lactate stereoisomers, we identify a previously unrecognized stereospecific adaptation that reinforces cytotoxic and proinflammatory programs. Although both D- and L-lactate impacted histone acetylation and metabolic activity, only D-lactate increased IFN-{gamma} and TNF- production and most potently promoted cytotoxic function. D-lactate also selectively enhanced mTORC1 and ERK1/ERK2 signaling, although these changes were not sufficient to fully explain the distinctive phenotype. Instead, the decisive feature of D-lactate supplementation was a reduction in mitochondrial reactive oxygen species (ROS), associated with electron transport chain (ETC) remodeling and enhanced glyoxalase-dependent buffering. Together, these findings identify a stereospecific lactate redox axis promoting cytotoxic Th1 cell differentiation.

immunology↗

bioRxiv2025

Somatic mutations in ALS genes in the motor cortex of sporadic ALS patients

Amyotrophic lateral sclerosis (ALS) is characterized by the progressive degeneration of cortical and spinal motor neurons. Mendelian germline mutations often cause familial ALS (fALS) but only approximately ten percent of sporadic ALS cases (sALS). We leveraged DNA and single cell RNA-sequencing data from autopsy tissue to explore the presence of somatic mosaic variants in sALS cases. Deep targeted panel sequencing of known ALS disease genes in motor cortex tissue revealed an enrichment of low allele frequency variants in sALS, but not in fALS with an identified monogenic cause. In silico analysis predicted increased pathogenicity of mosaic mutations in various known ALS mutational hot spots. In particular, we identified the somatic FUS variant p.E516X, located in an established hot spot for germline ALS mutations, which leads to nucleo-cytoplasmic mislocalization and aggregation typical for ALS FUS pathology. Additionally, we performed somatic variant calling on single cell RNA-sequencing data from sALS tissue and revealed a specific accumulation of somatic variants in excitatory neurons, reinforcing a neuron-autonomous disease initiation. Collectively, this study indicates that somatic mutations within the motor cortex, especially in excitatory neurons, may contribute to sALS development.

genetics↗

bioRxiv2024

RIG-I mediated neuron-specific IFN type 1 signaling in FUS-ALS induces neurodegeneration and offers new biomarker-driven individualized treatment options for (FUS-)ALS

Recent research has demonstrated significant aberrant activation of the innate immune system in ALS model systems due to mutations in SOD1, TARDBP and C9orf72 through stimulation of the TBK1-IRF3 pathway. This pathway can be activated, for example, by cGAS-STING-dependent sensing of cytosolic DNA that accumulates as a result of chronic DNA damage and defective mitochondria, both of which have been identified as early pathology in FUS-ALS spinal motor neurons (sMNs). Therefore, we analysed innate immune pathways in isogenic and non-isogenic FUSmut iPSC-derived sMNs, which revealed upregulation of interferon-stimulated genes (ISGs) and activation of the TBK1-IRF3 pathway in FUSmut sMNs. Notably, we found evidence for accumulation of cytosolic dsRNA and its sensor RIG-I in FUS-ALS. RIG-I, but not MDA5, was found to be significantly upregulated in FUSmut sMNs, and siRNA-mediated knockdown abolished the increased IFN1 activation in FUSmut sMNs. In post-mortem analysis, RIG-I was highly expressed in the remaining -MNs. IFN treatment of FUSwt sMNs phenocopied the axonal degeneration of FUSmut sMNs. Mechanistically, DNA damage induction did not increase ISG expression, but dsRNA was increased in the mitochondria of FUSmut sMNs. Mitochondrial transcription, a known source of dsRNA, was found to be upregulated in compartmental axonal RNAseq analysis and its inhibition reduced ISGs in FUS-ALS sMNs. Furthermore, the JAK-STAT inhibitor ruxolitinib alleviated the upregulated ISG expression and reversed the axonal degeneration of sMNs. Finally, we analysed ISG expression in peripheral blood samples from 18 FUS-ALS patients, eight of whom had a significantly elevated interferon signature. Blood ISGs correlated with disease progression rate and negatively with disease duration. RIG-I-mediated innate immune activation in sMNs may be an interesting novel individualised biomarker-driven therapeutic target in (FUS-) ALS. A one-sentence summary of your paperRIG-I-I-mediated innate immune activation is found in FUS-ALS spinal motor neurons caused by cytosolic dsRNA accumulation due to mitochondrial transcriptional activation and is amenable to JAK-STAT inhibition and might thus be an interesting novel individualized biomarker-driven therapeutic approach in (FUS-) ALS

neuroscience↗

bioRxiv2024

DJ-1 mediates regulation of metabolism and immune response in Parkinsons disease astrocytes and Glioblastoma cells

An inverse correlation for the expression of Parkinsons disease (PD)- and cancer-associated genes has been previously reported. Genes that are upregulated in cancer are frequently downregulated in PD and vice versa. PARK7, encoding DJ-1, was initially identified as an oncogene, but loss of DJ-1 causes early-onset PD. However, it remains elusive how differential DJ-1 levels contribute to opposite cell fates in cancer and PD. Here, we demonstrate specific effects of differential DJ-1 protein levels on the energy metabolism and cell growth in patient-derived cellular models of PD and glioblastoma (GBM) cell lines. Impaired energy metabolism was associated with an increased immune response upon IL-1{beta} stimulation and increased apoptosis and decreased cell growth in models of PD, whereas in GBM cells increased metabolic activity translated into a reduced immune response and increased cell growth. Furthermore, we found decreased glutathione (GSH) synthesis and therefore increased levels of reactive oxygen species (ROS) and oxidized glutathione (GSSG) in models of DJ-1 deficiency and decreased ROS levels in GBM cell lines. Thus, the mechanism by which DJ-1 modulates these phenotypes is the same in both diseases. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=84 SRC="FIGDIR/small/621212v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@4eccb4org.highwire.dtl.DTLVardef@161669corg.highwire.dtl.DTLVardef@197bfc3org.highwire.dtl.DTLVardef@1aecb36_HPS_FORMAT_FIGEXP M_FIG C_FIG DJ-1 levels modulate GSSG/GSH ratio and ROS levels, which results in divergent effects on cell growth and immune response in DJ-1-dependent glial pathologies in glioblastoma and PD. In models of PD, DJ-1 level dependent phenotypes can be rescued by antioxidant treatment that reduces the GSSG/GSH ratio and ROS levels.

neuroscience↗

bioRxiv2023

A Th17 cell-intrinsic glutathione/mitochondrial-IL-22 axis protects against intestinal inflammation

Although the intestinal tract is a major site of reactive oxygen species (ROS) generation, the mechanisms by which antioxidant defense in gut T cells contribute to intestinal homeostasis are currently unknown. Here we show, using T cell-specific ablation of the catalytic subunit of glutamate cysteine ligase (Gclc), that the ensuing loss of glutathione (GSH) impairs the production of gut-protective IL-22 by Th17 cells within the lamina propria. Although Gclc ablation does not affect T cell cytokine secretion in the gut of mice at steady-state, infection with C. rodentium increases ROS, inhibits mitochondrial gene expression and mitochondrial function in Gclc-deficient Th17 cells. These mitochondrial deficits affect the PI3K/AKT/mTOR pathway, leading to reduced phosphorylation of the translation repressor 4E-BP1. As a consequence, the initiation of translation is restricted, resulting in decreased protein synthesis of IL-22. Loss of IL-22 results in poor bacterial clearance, enhanced intestinal damage, and high mortality. ROS-scavenging, reconstitution of IL-22 expression or IL-22 supplementation in vivo prevent the appearance of these pathologies. Our results demonstrate the existence of a previously unappreciated role for Th17 cell-intrinsic GSH coupling to promote mitochondrial function, IL-22 translation and signaling. These data reveal an axis that is essential for maintaining the integrity of the intestinal barrier and protecting it from damage caused by gastrointestinal infection. Executive summary- GSH-regulated Th17 cell-derived IL-22, but not IL-17 is required to maintain intestinal barrier integrity and to revent lethality following C. rodentium infection. - GCLC expression in IBD patients correlates positively with expression of genes related to gut integrity. - Gclc-deficient Th17 cells accumulate mitochondrial ROS, which is linked to impaired mitochondrial function, ysregulated PI3K/AKT/mTOR signaling and impaired translation of IL-22. - ROS-scavenging, IL-22 reconstitution or T cell-specific expression of IL-22 in Gclc-deficient T cells rescues utant mice from the lethal infection outcome in vivo.

immunology↗

bioRxiv2023

Glutathione supports lipid abundance in vivo

Cells rely on antioxidants to survive. The most abundant antioxidant is glutathione (GSH). The synthesis of GSH is non-redundantly controlled by the glutamate-cysteine ligase catalytic subunit (GCLC). GSH imbalance is implicated in many diseases, but the requirement for GSH in adult tissues is unclear. To interrogate this, we developed a series of in vivo models to induce Gclc deletion in adult animals. We find that GSH is essential to lipid abundance in vivo. GSH levels are reported to be highest in liver tissue, which is also a hub for lipid production. While the loss of GSH did not cause liver failure, it decreased lipogenic enzyme expression, circulating triglyceride levels, and fat stores. Mechanistically, we found that GSH promotes lipid abundance by repressing NRF2, a transcription factor induced by oxidative stress. These studies identify GSH as a fulcrum in the livers balance of redox buffering and triglyceride production.

biochemistry↗

bioRxiv2022

Collagen remodeling dictates pancreatic cancer bioenergetics and outcome through DDR1 activation or degradation

Pancreatic ductal adenocarcinoma (PDAC) is a highly desmoplastic, aggressive cancer that frequently progresses by liver metastasis1. Cancer-associated fibroblasts (CAF), extracellular matrix (ECM), and type I collagen (Col I) support2-5 or restrain PDAC progression and may impede blood supply and nutrient availability6-8. The dichotomous role of the stroma in PDAC, and the mechanisms through which it influences patient survival and enables desmoplastic cancers escape nutrient limitation remain poorly understood. Here we show that matrix metalloprotease (MMP)-cleaved or intact Col I (cCol I and iCol I, respectively) exert opposing effects on PDAC bioenergetics, macropinocytosis (MP), tumor growth and liver metastasis. While cCol I activates DDR1 (discoidin domain receptor-1)-NF-{kappa}B-p62-NRF2 signaling to promote PDAC growth, iCol I triggers DDR1 degradation and restrains PDAC growth. Patients whose tumors are enriched in iCol I and low in DDR1 and NRF2 have improved median survival compared to those enriched in cCol I, DDR1 and NRF2. Inhibition of DDR1-stimulated NF-{kappa}B or mitochondrial biogenesis blocked tumorigenesis in wildtype mice but not in mice expressing MMP-resistant Col I. In summary, the diverse effects of tumor stroma on PDAC growth, metastasis, and patient survival are mediated through the Col I-DDR1-NF-{kappa}B-NRF2-mitochondrial biogenesis pathway, presenting multiple new opportunities for PDAC therapy.

cancer biology↗

bioRxiv2021

Metabolic reprogramming of cytotoxic T lymphocytes by high glucose enhances pancreatic beta cell apoptosis via TRAIL

Cytotoxic T lymphocytes (CTLs) are involved in development of diabetes. However, the impact of excessive glucose on CTL-mediated antigen-independent killing remains elusive. Here, we report that TNF-related apoptosis inducing ligand (TRAIL) is substantially up- regulated in CTLs in environments with high glucose (HG) both in vitro and in vivo. The PI3K- Akt-NF{kappa}B axis and non-mitochondrial reactive oxygen species are essential in HG-induced TRAIL upregulation in CTLs. TRAILhigh CTLs induce apoptosis of pancreatic beta cell line 1.4E7. Metformin and Vitamin D synergistically reduce HG-enhanced expression of TRAIL in CTLs and coherently protect 1.4E7 cells from TRAIL-mediated apoptosis. Notably, in patients with diabetes, correlation between Vitamin D concentrations in plasma and glucose levels is linked to HG-enhanced TRAIL expression on CTLs. Microarray data reveal that OXCT2, an important enzyme in ketone body catabolism, is a promising target in response to vitamin D. Our work not only reveals a novel mechanism of CTL involvement in progression of diabetes, but also establishes CTLs as a target for combined metformin and vitamin D therapy to protect pancreatic beta cells of diabetic patients.

immunology↗

bioRxiv2021

Deprivation of dietary fiber in specific-pathogen-free mice promotes susceptibility to the intestinal mucosal pathogen Citrobacter rodentium

The change of dietary habits in Western societies, including reduced consumption of fiber, is linked to alterations in gut microbial ecology. Nevertheless, mechanistic connections between diet-induced microbiota changes that affect colonization resistance and enteric pathogen susceptibility are still emerging. We sought to investigate how a diet devoid of soluble plant fibers impacts the structure and function of a conventional gut microbiota in specific-pathogen-free (SPF) mice and how such changes alter susceptibility to a rodent enteric pathogen. We show that absence of dietary fiber intake leads to shifts in the abundances of specific taxa, microbiome-mediated erosion of the colonic mucus barrier, a reduction of intestinal barrier-promoting short-chain fatty acids, and increases in markers of mucosal barrier integrity disruption. Importantly, our results highlight that these low fiber diet-induced changes in the gut microbial ecology collectively contribute to a lethal colitis by the mucosal pathogen Citrobacter rodentium, which is used as a mouse model for enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC, respectively). Our study indicates that modern, low-fiber Western diets might make individuals more prone to infection by enteric pathogens via the disruption of mucosal barrier integrity by diet-driven changes in the gut microbiota, illustrating possible implications for EPEC and EHEC infections.

microbiology↗

bioRxiv2021

Mitochondrial One-Carbon Flux has a Growth-Independent Role in Promoting Breast Cancer Metastasis

Progression of primary cancer to metastatic disease is the most common cause of death in cancer patients with minimal treatment options available. Canonical drugs target mainly the proliferative capacity of cancer cells, which often leaves slow-proliferating, persistent cancer cells unaffected. Metabolic determinants that contribute to growth-independent functions supporting resistance and metastatic dissemination are still poorly understood. In the present study, we revealed that antifolate treatment results in an uncoupled and autarkic mitochondrial one-carbon (1C) metabolism allowing sustained serine catabolism and formate overflow when cytosolic 1C metabolism is impaired. Interestingly, antifolate dependent growth-arrest did not correlate with decreased migration capacity. Therefore, using the antifolate Methotrexate as a tool compound allowed us to disentangle proliferation and migration to profile the metabolic phenotype of migrating (growth-arrested) cells. Supported by an increased NAD/NADH ratio, we observed increased serine de novo synthesis and increased serine catabolism to formate. Consequently, inhibition of serine de novo synthesis using the competitive PHGDH-inhibitor BI-4916 or direct inhibition of mitochondrial 1C metabolism reduced cancer cell migration. Using an orthotopic breast cancer model, we show that sole inhibition of mitochondrial serine catabolism does not affect primary tumor growth but strongly inhibits pulmonary metastasis. We conclude that mitochondrial 1C metabolism, despite being dispensable for proliferative capacities, confers an advantage to cancer cells by supporting their motility potential. Our results improve our understanding of 1C metabolism and of metabolic determinants that support the process of cancer cell migration and metastasis.

cancer biology↗

bioRxiv2021

DJ-1 depletion slows down immunoaging in T-cell compartments

Decline in immune function during aging increases susceptibility to different aging related diseases. However, the underlying molecular mechanisms, especially the genetic factors contributing to imbalance of naive/memory T-cell subpopulations, still remain largely elusive. Here we show that loss of DJ-1 encoded by PARK7/DJ-1, causing early-onset familial Parkinsons disease (PD), unexpectedly delayed immunoaging in both human and mice. Compared with two gender-matched unaffected sibling carriers of similar ages, the index PD patient with DJ-1 deficiency showed a decline in many critical immunoaging features, including almost doubled frequencies of non-senescent T cells. The observation of a younger immune system in the index patient was further consolidated by the results in aged DJ-1 knockout mice. Our data from bone marrow chimera models and adoptive transfer experiments demonstrated that DJ-1 regulates several immunoaging features via hematopoietic-intrinsic and naive-CD8-intrinsic mechanisms. Our finding suggests an unrecognized critical role of DJ-1 in regulating immunoaging, discovering a potent target to interfere with immunoaging- and aging-associated diseases.

immunology↗

bioRxiv2020

MondoA Drives Malignancy in cALL through Enhanced Adaptation to Metabolic Stress

Cancer cells are in most instances characterized by rapid proliferation and uncontrolled cell division. Hence, they must adapt to proliferation-induced metabolic stress through intrinsic or acquired anti-metabolic stress responses to maintain homeostasis and survival. One mechanism to achieve this is to reprogram gene expression in a metabolism-dependent manner. MondoA (also known as MLXIP), a member of the MYC interactome, has been described as an example of such a metabolic sensor. However, the role of MondoA in malignancy is not fully understood and the underlying mechanism in metabolic responses remains elusive. By assessing patient data sets we found that MondoA overexpression is associated with a worse survival in pediatric common acute lymphoblastic leukemia (cALL). Using CRISPR/Cas9 and RNA interference approaches, we observed that MondoA depletion reduces transformational capacity of cALL cells in vitro and dramatically inhibits malignant potential in an in vivo mouse model. Interestingly, reduced expression of MondoA in patient data sets correlated with enrichment in metabolic pathways. The loss of MondoA correlated with increased tricarboxylic acid (TCA) cycle activity. Mechanistically, MondoA senses metabolic stress in cALL cells by restricting oxidative phosphorylation through reduced PDH activity. Glutamine starvation conditions greatly enhance this effect and highlight the inability to mitigate metabolic stress upon loss of MondoA in cALL. Our findings give a novel insight into the function of MondoA in pediatric cALL and support the notion that MondoA inhibition in this entity offers a therapeutic opportunity and should be further explored. Key PointsMondoA maintains aggressiveness and leukemic burden in common ALL, modulating metabolic stress response.

cancer biology↗

bioRxiv2019

PARK7/DJ-1 promotes pyruvate dehydrogenase activity and maintains Treg homeostasis

Pyruvate dehydrogenase (PDH) is the gatekeeper enzyme into the tricarboxylic acid (TCA) cycle. Here we show that PARK7/DJ-1, a key familial Parkinsons disease (PD) gene, is a pacemaker controlling PDH activity in CD4 regulatory T cells (Tregs). DJ-1 bound to PDH-E1 beta (PDHB), inhibiting the phosphorylation of PDH-E1 alpha (PDHA), thus promoting PDH activity and oxidative phosphorylation (OXPHOS). Dj-1 depletion impaired Treg proliferation and cellularity maintenance in older mice, increasing the severity during the remission phase of experimental autoimmune encephalomyelitis (EAE). The compromised proliferation and differentiation of Tregs in Dj-1 knockout mice were caused via regulating PDH activity. These findings provide novel insight into the already complicated regulatory machinery of the PDH complex and demonstrate that the DJ-1-PDHB axis represents a potent target to maintain Treg homeostasis, which is dysregulated in many complex diseases.

biochemistry↗

bioRxiv2019

Cytogenetically-based biodosimetry after high doses of radiation

Dosimetry is an important tool for triage and treatment planning following any radiation exposure accident, and biological dosimetry, which estimates exposure dose using a biological parameter, is a practical means of determining the specific dose an individual receives. The cytokinesis-blocked micronucleus assay (CBMN) is an established biodosimetric tool to measure chromosomal damage in mitogen-stimulated human lymphocytes. The CBMN method is especially valuable for biodosimetry in triage situations thanks to simplicity in scoring and adaptability to high-throughput automated sample processing systems. While this technique produces dose-response data which fit very well to a linear-quadratic model for exposures to low linear energy transfer (LET) radiation and for doses up for 5 Gy, limitations to the accuracy of this method arise at larger doses. Resolution at higher doses is limited by the number of cells reaching mitosis. Whereas it would be expected that the yield of micronuclei increases with the dose, in many experiments it has been shown to actually decrease when normalized over the total number of cells. This variation from a monotonically increasing dose response poses a limitation for retrospective dose reconstruction. In this study we modified the standard CBMN assay to increase its resolution following exposures to higher doses of photons or a mixed neutron-photon beam. The assay is modified either through inhibitions of the G2/M and spindle checkpoints with the addition of caffeine and/or ZM447439 (an Aurora kinase inhibitor), respectively to the blood cultures at select times during the assay. Our results showed that caffeine addition improved assay performance for photon up to 10 Gy. This was achieved by extending the assay time from the typical 70 h to just 74 h. Compared to micronuclei yields without inhibitors, addition of caffeine and ZM447439 resulted in improved accuracy in the detection of micronuclei yields up to 10 Gy from photons and 4 Gy of mixed neutrons-photons. When the dose-effect curves were fitted to take into account the turnover phenomenon observed at higher doses, best fitting was achieved when the combination of both inhibitors was used. These techniques permit reliable dose reconstruction after high doses of radiation with a method that can be adapted to high-throughput automated sample processing systems.

cell biology↗