Biology subjects

Ballard, E.

Publications and source records attributed to Ballard, E..

4 recordsLinked to original sources

bioRxiv2026

Testis-Specific MAGEA3/6 Regulate Glycolysis to Promote Metabolic Flexibility and Reveal Therapeutic Vulnerabilities in Pancreatic Cancer Cells

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive tumor characterized by metabolic plasticity that enables cancer cells to survive nutrient deprivation and therapeutic stress. Melanoma-associated antigens A3 and A6 (MAGEA3/6), members of the cancer-testis antigen family with a previously identified protective role in spermatogenesis during nutritional stress, have been implicated in cancer progression and metabolic regulation. However, their contribution to metabolic adaptation in pancreatic cancer remains poorly understood. Here, we investigated the molecular mechanisms underlying MAGEA3/6-mediated resistance to glycolytic inhibition using complementary gain- and loss-of-function models, pharmacological inhibition of metabolic pathways, cellular metabolic assays, and integrated transcriptomic, proteomic, metabolomic, and lipidomic analyses. MAGEA3/6 expression enhanced resistance to 2-deoxy-D-glucose (2-DG), with MAGEA6-expressing MIA PaCa-2 cells exhibiting a greater than 2.5-fold increase in the half-maximal inhibitory concentration (IC50). Conversely, MAGEA3/6 depletion reduced clonogenic growth and migration and increased sensitivity to 2-DG. Resistance persisted despite pharmacological inhibition of mTORC1, the pentose phosphate pathway, or glutaminase, suggesting metabolic adaptations beyond these pathways. Unexpectedly, MAGEA6 expression was associated with increased rather than decreased AMPK1 protein abundance, contrasting with previously reported MAGEA3/6-mediated AMPK degradation and suggesting context-dependent regulation of this master regulator of cellular metabolism. MAGEA6 also reduced hexokinase HK1 and HK2 abundance while increasing several downstream glycolytic enzymes, revealing discordant regulation of glycolysis. Seahorse analyses and integrated multi-omics profiling identified extensive remodeling of mitochondrial metabolism, glutamine-aspartate metabolism, phospholipid composition, lipid storage, and redox homeostasis. Interestingly, despite enhanced resistance to glycolytic inhibition, MAGEA6-expressing cells exhibited increased sensitivity to hydrogen peroxide-induced oxidative stress, revealing a potential metabolic vulnerability. Given that MAGEA3/6 are physiologically expressed primarily in the male germline during early spermatogenesis, a process highly sensitive to metabolic and oxidative stress, these findings also raise important questions about their physiological roles in protecting developing germ cells and maintaining metabolic and redox homeostasis. Together, our findings recognize MAGEA3/6 as regulators of metabolic plasticity in PDAC and highlight how understanding their molecular functions in both spermatogenesis and cancer may uncover previously unrecognized metabolic vulnerabilities and potential therapeutic opportunities.

cancer biology↗

bioRxiv2024

TASOR expression in naive embryonic stem cells safeguards their developmental potential

The seamless transition through stages of pluripotency relies on a delicate balance between transcription factor networks and epigenetic silencing mechanisms that ensure proper regulation of the developmental program, critical for normal development. Here, we uncover the pivotal role of the transgene activation suppressor (TASOR), a component of the human silencing hub (HUSH) complex, in sustaining cell viability during the transition from naive to primed pluripotency, despite its rapid downregulation during this transition. Loss of TASOR in naive cells triggers replication stress, disrupts H3K9me3 heterochromatin formation, and compromise the transcriptional and post-transcriptional silencing of LINE-1 (L1) transposable elements (TEs), with these effects become more pronounced in primed cells. Remarkably, the survival of Tasor-knockout cells during naive to primed transition can be restored through the inhibition of cysteine-aspartic acid protease (Caspase) or deletion of mitochondrial antiviral signaling protein (MAVS). This suggests that unscheduled L1 expression activates an innate immune response, leading to programmed cell death, specifically in cells exiting naive pluripotency. Additionally, we propose that HUSH-promoted H3K9me3 in naive PSCs sets the stage for ensuing DNA methylation in primed cells, establishing long-term silencing during differentiation. Our findings shed insights on the crucial impact of epigenetic programs established in early developmental stages on subsequent phases, underscoring their significance in the developmental process.

developmental biology↗

bioRxiv2024

An inappropriate decline in ribosome levels drives a diverse set of neurodevelopmental disorders

Many neurodevelopmental defects are linked to perturbations in genes involved in housekeeping functions, such as those encoding ribosome biogenesis factors. However, how reductions in ribosome biogenesis can result in tissue and developmental specific defects remains a mystery. Here we describe new allelic variants in the ribosome biogenesis factor AIRIM primarily associated with neurodevelopmental disorders. Using human cerebral organoids in combination with proteomic analysis, single-cell transcriptome analysis across multiple developmental stages, and single organoid translatome analysis, we identify a previously unappreciated mechanism linking changes in ribosome levels and the timing of cell fate specification during early brain development. We find ribosome levels decrease during neuroepithelial differentiation, making differentiating cells particularly vulnerable to perturbations in ribosome biogenesis during this time. Reduced ribosome availability more profoundly impacts the translation of specific transcripts, disrupting both survival and cell fate commitment of transitioning neuroepithelia. Enhancing mTOR activity by both genetic and pharmacologic approaches ameliorates the growth and developmental defects associated with intellectual disability linked variants, identifying potential treatment options for specific brain ribosomopathies. This work reveals the cellular and molecular origins of protein synthesis defect-related disorders of human brain development. HighlightsO_LIAIRIM variants reduce ribosome levels specifically in neural progenitor cells. C_LIO_LIInappropriately low ribosome levels cause a transient delay in radial glia fate commitment. C_LIO_LIReduced ribosome levels impair translation of a selected subset of mRNAs. C_LIO_LIGenetic and pharmacologic activation of mTORC1 suppresses AIRIM-linked phenotypes. C_LI

developmental biology↗

bioRxiv2021

Tracing patterns of evolution and acquisition of drug resistant Aspergillus fumigatus infection from the environment using population genomics

Infections caused by opportunistic fungal pathogens are increasingly resistant to first-line azole antifungal drugs. However, despite its clinical importance, little is known about the extent to which susceptible patients acquire infection from drug resistant genotypes in the environment. Here, we present a population genomic analysis of the mould Aspergillus fumigatus from across the United Kingdom and Republic of Ireland. First, we show occurrences where azole resistant isolates of near identical genotypes were obtained from both environmental and clinical sources, indicating with high confidence the infection of patients with resistant isolates transmitted from the environment. Second, we find that the fungus is structured into two clades ( A and B) with little interclade recombination and the majority of environmental azole resistance genetically clustered inside Clade A. Genome-scans show the impact of selective sweeps across multiple regions of the genome. These signatures of positive selection are seen in regions containing canonical genes encoding fungicide resistance in the ergosterol biosynthetic pathway, whilst other regions under selection have no defined function. Phenotyping identified genes in these regions that could act as modifiers of resistance showing the utility of reverse genetic approaches to dissect the complex genomic architecture of fungal drug resistance. Understanding the environmental drivers and genetic basis of evolving fungal drug resistance needs urgent attention, especially in light of increasing numbers of patients with severe viral respiratory tract infections who are susceptible to opportunistic fungal superinfections.

genomics↗