Biology subjects

Lee, V.

Publications and source records attributed to Lee, V..

At least 19 recordsLinked to original sources

bioRxiv2026

Pulsed priming with the FAK inhibitor narmafotinib enhances both gemcitabine/Abraxane and FOLFIRINOX chemotherapy response in pancreatic cancer

BackgroundPancreatic ductal adenocarcinoma (PDAC) is a particularly lethal malignancy with few treatment options available. Extensive remodelling of extracellular matrix (ECM) generates a highly fibrotic tumour landscape, which impairs therapeutic response. ObjectiveWe investigated whether stromal priming via the highly specific Focal Adhesion Kinase (FAK) inhibitor narmafotinib (AMP945) in combination with the two major standard-of-care chemotherapies in PDAC, gemcitabine/Abraxane and FOLFIRINOX, reduces fibrosis and enhances treatment efficacy. Design3D organotypic matrices, intravital imaging, and in vivo subcutaneous and orthotopic PDAC models were used to provide a rationale for a first-line priming regimen of narmafotinib prior to chemotherapy. ResultsNeoadjuvant chemotherapy induces fibrosis in PDAC indicating a need for upfront first-line priming of the ECM to normalise the stroma for optimal treatment response. Narmafotinib is a new potent small molecule FAK inhibitor. Phase I safety data shows excellent safety, tolerability, and pharmacokinetics following oral administration in humans. We reveal that narmafotinib treatment during early ECM remodelling ( priming) reduces fibrosis, while limiting subsequent PDAC invasion. Moreover, intravital imaging demonstrates real-time FAK inactivation and cell cycle stalling, leading to improved chemotherapeutic efficacy upon narmafotinib priming in vivo. Long-term assessment in patient-derived models shows that narmafotinib priming prior to gemcitabine/Abraxane or FOLFIRINOX reduces PDAC progression and extends survival in both chemotherapy settings. ConclusionsOur results using these Phase II-ready drug combinations strongly support the clinical assessment of narmafotinib in PDAC. Narmafotinib is currently in Phase Ib/IIa trials, assessing a pulsed dosing regimen prior to gemcitabine/Abraxane, and warrants further clinical assessment in combination with FOLFIRINOX. SIGNIFICANCE OF THIS STUDYO_ST_ABSWhat is already known on this topicC_ST_ABSO_LIPancreatic cancer (PC) is one of the most lethal malignancies and is characterised by a dense, fibrotic stroma, which impairs chemotherapy efficacy. C_LIO_LIThe non-receptor tyrosine kinase FAK is known to promote cancer fibrosis and therefore represents a therapeutic target to normalise the PC stroma and to improve chemotherapy performance. C_LI What this study addsO_LINeoadjuvant chemotherapy induces early fibrosis indicating a need for upfront first-line priming of the ECM to blunt or normalise stromal fibrosis for optimal response to therapy. C_LIO_LIThe small molecule inhibitor narmafotinib (which is currently under Phase Ib/IIa clinical trial assessment) shows high specificity towards FAK as well as desirable pharmacokinetics and pharmacodynamics in healthy human volunteers. C_LIO_LIEarly short-term narmafotinib priming reduces fibrosis and improves the efficacy of subsequent standard-of-care gemcitabine/Abraxane chemotherapy. C_LIO_LIFOLFIRINOX (oxaliplatin, irinotecan, leucovorin and 5-fluorouracil) is a multi-agent chemotherapy preferentially used in PDAC patients with good performance status. Our results demonstrate that narmafotinib priming also improves FOLFIRINOX efficacy, leading to extended survival in patient-derived PDAC models. C_LI How this study might affect research, practice, or policyO_LIThis study supports the clinical development of narmafotinib in combination with both gemcitabine/Abraxane (ACCENT trial) and further FOLFIRINOX standard-of-care chemotherapies for PDAC patient treatment. C_LIO_LIThe first-line priming strategy and early ECM normalisation used in this study may also be applicable to other combination therapy settings and warrants further investigation in ongoing clinical studies. C_LI

cancer biology↗

bioRxiv2026

RNA exosome-mediated RNA surveillance governs developmental timing in the human cerebellum

Defects in RNA metabolism are a defining feature of neurodevelopmental disease, yet how RNA decay pathways contribute to human brain development remains poorly understood. Mutations in ubiquitously expressed RNA surveillance factors often cause highly tissue-selective disease, highlighting a central paradox in human biology. The RNA exosome is a conserved ribonuclease complex traditionally viewed as a housekeeping machine for RNA turnover, yet recessive mutations in genes encoding structural subunits of the complex disproportionately cause neurological disease, suggesting an instructive role in nervous system development. Here, we show that the RNA exosome regulates the temporal progression of gene expression programs during human cerebellar differentiation. Using CRISPR-engineered human cerebellar organoids modeling EXOSC3 variants, we find that RNA exosome dysfunction does not broadly alter transcript abundance, but instead disrupts transitions between developmental states. Mutant organoids exhibit incomplete and mis-timed resolution of early transcriptional programs, altered lineage specificity, and impaired coordination of maturation-associated gene expression programs, with pronounced effects in neuronal lineages, particularly Purkinje cells and rhombic lip-derivatives. These defects are accompanied by disorganized laminar architecture and reduced coordination of neuronal activity, despite preserved intrinsic excitability. Together, our findings establish RNA surveillance as a key regulator of developmental timing, lineage fidelity, and neurodevelopmental disease.

molecular biology↗

bioRxiv2026

Community assembly explains invasion differences between two contrasting forest types

Plant communities within a metacommunity can vary widely in their degree of invasion by introduced species. Disturbance, propagule pressure, and biotic resistance are common explanations for this variation, but empirical evidence for these hypotheses is mixed. Alternatively, the community assembly framework predicts that local assembly filters determine both native and exotic composition, but lower trait variation in the introduced species pool may exclude them from certain sites. We examined evidence for this framework using observational data from forests and woodlands of Long Island, NY, USA. These forests vary in vegetation composition and invasion along a soil gradient. They are also highly disturbed and fragmented, yet some stands have almost no introduced plants. Using data collected in 1998 and 2021-22, we quantified relationships between community composition, soil characteristics, and functional traits for native and exotic assemblages, as indicators of environmental filtering. We found similar trait-environment relationships in native and introduced species, suggesting that both groups follow the same local assembly rules. Introduced species were predominantly found in sites with more nutrient-rich soils and were absent from sites with nutrient-poor soils. At the regional scale, the exotic species pool was biased toward trait values favored in more nutrient-rich environments, particularly high growth rates and low leaf C:N ratios, which explains their absence from nutrient-poor environments. These patterns were consistent over time, and stands that were uninvaded in 1998 remained so in 2021-22, supporting the robustness and reliability of short-term studies. This study shows that invasion patterns in plant communities can be explained by the assembly rules that govern native species. By linking local environmental filtering with regional species pool characteristics, this work advances our understanding of how some communities remain uninvaded despite high disturbance and propagule pressure. Overall, these results highlight the utility of the community assembly framework, and emphasize the importance of regional processes in constraining the local distribution of introduced species.

ecology↗

bioRxiv2026

Integrative Multi-Omics Analysis Identifies a Functional Enhancer Driving Tumorigenesis in Head and Neck Squamous Cell Carcinoma

Enhancer is a critical epigenetic feature in head and neck squamous cell carcinoma (HNSCC), yet the functional roles of individual enhancers remain poorly understood. Here, we conducted an integrative multi-omics analysis based on publicly available ATAC-seq, H3K27ac ChIP-seq, transcriptomic profiling, and genetic association datasets to systematically map HNSCC-associated enhancers and their target genes. Integrating ATAC-seq and H3K27ac ChIP-seq, we identified 20,362 enhancers and 18,040 enhancer-associated genes, highlighting widespread regulatory complexity. Functional characterization of the TERT-associated enhancer GH05J001312 (GRCh38/hg38: chr5:1312099-1317743) revealed strong transcriptional activity in HNSCC. CRISPR-mediated deletion of a core sequence significantly reduced TERT expression, impaired cellular proliferation in vitro, and suppressed tumor growth in vivo, confirming its role as a key cis-regulatory element. RNA-seq analysis of enhancer-edited cells uncovered 742 differentially expressed genes enriched in cancer-related pathways, including MAPK and IL-17 signaling, indicating a broad transcriptional impact. Collectively, our findings establish GH05J001312 as a functional enhancer driving oncogenic programs in HNSCC and suggest enhancer-targeted strategies as a potential therapeutic avenue.

cancer biology↗

bioRxiv2026

Epithelial Reprogramming and Transition during Pulmonary Bioengineering

Recent research has emphasized the critical role of cell state transitions in tissue homeostasis. In lung biology, transitional cells are recognized as a feature of tissue-scale processes during both normal physiology and disease. The precise way that transitional cell states emerge and are regulated remains to be determined. Engineered tissues, built in a laboratory through bioengineering approaches, allow detailed study of cellular states that are not commonly found in native biology, and allow opportunities to directly induce and manipulate cellular transitions. The following study explores and characterizes epithelial cell states that emerge via cellular reprogramming in a tissue engineering context. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=172 SRC="FIGDIR/small/701406v1_ufig1.gif" ALT="Figure 1"> View larger version (68K): org.highwire.dtl.DTLVardef@1d456f3org.highwire.dtl.DTLVardef@1989ba5org.highwire.dtl.DTLVardef@127dd7org.highwire.dtl.DTLVardef@3dd7a_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2025

Vitreous Inflammation as an Early Indicator of Retinal Ganglion Cell Loss Following Acute Optic Nerve Injury in Mice

Retinal ganglion cell (RGC) degeneration in optic neuropathies is often preceded by neuroinflammatory changes, yet the earliest in vivo indicators of this process remain poorly defined. Here, we identified vitreous hyperreflective foci (VHRFs) by visible-light optical coherence tomography (vis-OCT) as an early inflammatory signature of RGC injury. Longitudinal vis-OCT imaging after optic nerve crush (ONC) revealed that VHRFs emerged as early as 6 hours post-injury and peaked before the significant RGC loss. Confocal analysis showed that these VHRFs corresponded to activated amoeboid microglia undergoing vertical migration from the outer to inner retina and horizontal movement toward the optic nerve head area. Similar amoeboid microglia were also observed in the anterior segment, suggesting a global ocular inflammatory response to the ONC injury. RNAscope in situ hybridization further demonstrated elevated IL-1{beta} expression in vitreous amoeboid microglia. Moreover, pharmacological blockade of IL-1 signaling with an IL-1 receptor antagonist significantly reduced VHRFs, suppressed microglial migration, and delayed RGC loss. Taken together, our findings identify VHRFs as a previously unrecognized early danger signal for RGC degeneration and highlight IL-1-mediated inflammation as a tractable early therapeutic target for preventing RGC degeneration and vision loss. Graphical Overview O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=88 SRC="FIGDIR/small/694725v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1598c4aorg.highwire.dtl.DTLVardef@9637borg.highwire.dtl.DTLVardef@623bf4org.highwire.dtl.DTLVardef@14e21ce_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2025

ROCK2 inhibition has a dual role in reducing ECM remodelling and cell growth, while impairing migration and invasion

The Rho-associated coiled-coil containing protein kinases 1/2 (ROCK1/2) are key signalling proteins involved in the regulation of the actin cytoskeleton and control a variety of cellular processes. This includes cell proliferation, stemness, cell migration and invasion as well as actomyosin contraction and extracellular matrix (ECM) remodelling. Due to a lack of ROCK2 specific inhibitors, previous pharmacological studies of ROCK function have relied on pan-ROCK1/2 inhibition. Here, we use the ROCK2 specific inhibitor, GV101, in the context of breast cancer (BC) models to uncouple the effects of ROCK2 pharmacological inhibition on both epithelial and stromal fibroblast cell populations. We demonstrate that ROCK2 inhibition with GV101 reduces fibroblast-mediated remodelling of pre-existing and de novo synthesised ECM resulting in a reduction in biomechanical stiffness, while also limiting epithelial cell growth in 2D and 3D settings. We also demonstrate that ROCK2 inhibition exposes epithelial cell vulnerability to fluid flow-induced shear stress. Furthermore, using 3D co-cultures we reveal that GV101 reduces single-cell migratory capacity, while the disruption of stromal ECM architecture is sufficient to impede collective cell migration and invasion. Finally, we assessed ROCK2 expression in human BC patient tumours revealing that ROCK2 expression is up-regulated during BC progression and that high ROCK2 expression correlates with poor patient outcome in the triple-negative subtype of BC. Together, these results demonstrate that ROCK2 specific inhibition disrupts key functions in both epithelial cell and stromal fibroblast compartments warranting further assessment of ROCK2 in highly proliferative, fibrotic or metastatic diseases, such as BC. HighlightsO_LIFibroblast-mediated remodelling of pre-existing and de novo synthesised extracellular matrix is reduced upon ROCK2 specific targeting. C_LIO_LIROCK2 inhibition impairs epithelial cancer cell growth and colony formation in 2D and 3D contexts, while also limiting single-cell migration and cell survival upon fluid flow-induced shear stress. C_LIO_LIROCK2 targeting during fibroblast-mediated ECM remodelling is sufficient to disrupt collective cell migration as well as 3D invasion into organotypic fibroblast-contracted collagen matrices. C_LIO_LIROCK2 expression is up-regulated during breast cancer progression and high expression correlates with poor patient outcome in triple-negative breast cancer. C_LI

cell biology↗

bioRxiv2025

Discovery of Niclosamide Analogs with Potent Mitochondrial Uncoupling Activity with reduced toxicity

Mitochondrial uncouplers have shown clinical potential across various diseases, including cancer. Niclosamide, an FDA-approved anthelmintic drug, acts as a mild mitochondrial uncoupler and has demonstrated anticancer activity in multiple preclinical cancer models. However, its clinical application remains limited, with some attributing this to poor bioavailability, while the underlying mechanisms are still unclear. Here, we demonstrate that niclosamide exhibits a dose-dependent biphasic effect, promoting uncoupling at low concentration while acting as a mitochondrial inhibitor at high concentration, which could restrict its therapeutic window and limit efficacy. To overcome this challenge, we aimed to develop next-generation mitochondrial uncouplers (MUs) by synthesizing and evaluating novel Niclosamide derivatives with enhanced therapeutic potential. Through structural modifications, we optimized uncoupling activity while reducing inhibitory toxicity, thereby expanding the pharmacological window. Our findings suggest that fine-tuning the molecular structure of mitochondrial uncouplers could provide a safer and more effective metabolic reprogramming strategy for cancer treatment.

pharmacology and toxicology↗

bioRxiv2025

A Tunable Pulmonary Organoid Model Demonstrates Compositionally Driven Epithelial Plasticity and Immune Polarization

Summary/AbstractAberrant epithelial regeneration and immune remodeling are hallmarks of chronic lung diseases such as idiopathic pulmonary fibrosis (IPF), COPD, and post-viral syndromes. Yet how cellular context shapes these trajectories remains unresolved. We present a tunable, primary rat-derived lung organoid model that systematically varies immune, epithelial, and mesenchymal inputs to reveal how composition alone dictates epithelial plasticity and macrophage polarization. Across organoid conditions that varied by relative starting lineage ratios, we observed the spontaneous emergence of disease-relevant transitional cell states, including Sox9+ stressed progenitors, RAS-like intermediates, and hillock-like cells, alongside distinct macrophage activation profiles. In mesenchyme-rich contexts, epithelial-immune-mesenchymal crosstalk appeared to reinforce inflammatory signaling and stabilize transitional persistence, while immune-dominant inputs favored ATI-like repair and squamous remodeling. Hillock-like cells displayed context-specific polarization and expressed immune-regulatory genes, suggesting a role as epithelial orchestrators that help calibrate inflammatory response during regeneration. Connectomic analysis via NICHES revealed that regenerative outcomes were associated with dynamic multicellular signaling networks that integrate stress sensing, immune coordination, and epithelial resilience. This platform provides a tractable system for modeling milieu-specific repair and regenerative mechanisms and could inform therapeutic strategies aimed at redirecting epithelial fate in chronic lung disease.

bioengineering↗

bioRxiv2025

NAMPT activity plays a key role in driving autoimmune processes that characterize type 1 diabetes development in mice

Type 1 diabetes (T1D) is characterised by destruction of pancreatic beta cells by islet-infiltrating cytotoxic lymphocytes, and elevated intra-islet secretion of pro-inflammatory cytokines. However, the underlying pathophysiological mechanisms remain incompletely understood. We hypothesised that abnormal elevation of islet NAD, via activation of NAMPT, plays a key role in driving islet autoimmune processes in T1D. Here, we report that NAMPT inhibition protects against pro-inflammatory cytokine (IL-1{beta}, TNF and IFN{gamma}) mediated beta-cell dysfunction and apoptosis in isolated mouse and human islets. RNAseq revealed that NAMPT inhibition blocked cytokine-mediated gene expression linked to pro-inflammatory responses and leukocyte migration. In vivo, diabetes was induced in CD1 mice via multiple low dose streptozotocin (MLDS) injection. MLDS mice were administered the NAMPT inhibitor FK866 (10 mg/kg; IP) or saline equivalent for 16 days. These experiments demonstrated that NAMPT inhibition improved glycaemic control and beta-cell function and insulin content in MLDS mice. FK866 also reduced proportions of islet-residing TNF-producing CD4+T-cells and F4/80+macrophages, proliferation of spleen-derived CD4+ and CD8+T-cells, and proliferation of islet-derived CD4+T-cells and F4/80+macrophages. Finally, we report that NAMPT inhibition was able to block pro-inflammatory cytokine-mediated migration of cytotoxic CD8+T-cells into isolated islets, using an in vitro transwell platform. This data supports a key immunomodulatory role for NAMPT in islet autoimmunity. NAMPT inhibition may represent a novel therapeutic approach for T1D. The effects of increased NAD levels on islet inflammation require in-depth characterisation, and caution should be exercised with regard to use of NAD boosting supplements, particularly in individuals at risk of developing T1D.

cell biology↗

bioRxiv2024

Identification of Meibomian gland stem cell populations and mechanisms of aging

Meibomian glands secrete lipid-rich meibum, which prevents tear evaporation. Aging-related Meibomian gland shrinkage may result in part from stem cell exhaustion and is associated with evaporative dry eye disease, a common condition lacking effective treatment. The identities and niche of Meibomian gland stem cells and the signals controlling their activity are poorly defined. Using snRNA-seq, in vivo lineage tracing, ex vivo live imaging, and genetic studies in mice, we identified markers for stem cell populations that maintain distinct regions of the gland and uncovered Hh signaling as a key regulator of stem cell proliferation. Consistent with this, human Meibomian gland carcinoma exhibited increased Hh signaling. Aged glands displayed decreased Hh and EGF signaling, deficient innervation, and loss of collagen I in niche fibroblasts, indicating that alterations in both glandular epithelial cells and their surrounding microenvironment contribute to age-related degeneration. These findings suggest new approaches to treat aging-associated Meibomian gland loss.

cell biology↗

bioRxiv2024

Sox9 marks limbal stem cells and is required for asymmetric cell fate switch in the corneal epithelium

Adult tissues with high cellular turnover require a balance between stem cell renewal and differentiation, yet the mechanisms underlying this equilibrium are unclear. The cornea exhibits a polarized lateral flow of progenitors from the peripheral stem cell niche to the center; attributed to differences in cellular fate. To identify genes that are critical for regulating the asymmetric fates of limbal stem cells and their transient amplified progeny in the central cornea, we utilized an in vivo cell cycle reporter to isolate proliferating basal cells across the anterior ocular surface epithelium and performed single-cell transcriptional analysis. This strategy greatly increased the resolution and revealed distinct basal cell identities with unique expression profiles of structural genes and transcription factors. We focused on Sox9; a transcription factor implicated in stem cell regulation across various organs. Sox9 was found to be differentially expressed between limbal stem cells and their progeny in the central corneal. Lineage tracing analysis confirmed that Sox9 marks long-lived limbal stem cells and conditional deletion led to abnormal differentiation and squamous metaplasia in the central cornea. These data suggest a requirement for Sox9 for the switch to asymmetric fate and commitment toward differentiation, as transient cells exit the limbal niche. By inhibiting terminal differentiation of corneal progenitors and forcing them into perpetual symmetric divisions, we replicated the Sox9 loss-of-function phenotype. Our findings reveal an essential role for Sox9 for the spatial regulation of asymmetric fate in the corneal epithelium that is required to sustain tissue homeostasis.

developmental biology↗

bioRxiv2024

ACSS2 upregulation enhances neuronal resilience to aging and tau-associated neurodegeneration

Epigenetic mechanisms, including histone acetylation, are pivotal for learning and memory, with a role in neuronal function in Alzheimers disease and Related Dementia (ADRD). Acetyl-CoA synthetase 2 (ACSS2), an enzyme that generates acetyl-CoA, is central to histone acetylation and gene regulation, particularly in neurons, due to their unique metabolic demands and postmitotic state. ACSS2 can be recruited to the nucleus and chromatin, locally supplying acetyl-CoA to directly fuel histone acetyltransferase enzymes and key neuronal gene expression. This regulatory mechanism may be a promising target for therapeutic intervention in neurodegenerative diseases. Previously we showed that systemic ACSS2 deletion in mice, although largely normal in physiology, is greatly impaired in memory. Here we investigated whether increasing ACSS2 levels could protect neurons against disease and age-associated cognitive decline. Given the role of tau in ADRD, we used primary hippocampal neurons that mimic the sporadic development of tau pathology and the P301S transgenic mouse model for tau-induced memory decline. Our results show that ACSS2 upregulation mitigates tau-induced transcriptional alterations, enhances neuronal resilience against tau pathology, improves long-term potentiation, and ameliorates memory deficits. Expanding upon these findings, we reveal that increasing histone acetylation through ACSS2 upregulation improves age-associated memory decline. These findings indicate that increasing ACSS2 is highly effective in countering age- and tau-induced transcriptome changes, preserving elevated levels of synaptic genes, and safeguarding synaptic integrity. We thus highlight ACSS2 as a key player in the epigenetic regulation of cognitive aging and ADRD, providing a foundation for targeted therapeutics to enhance brain resilience and function. SummaryACSS2 upregulation protects neurons from disease and age-related decline by enhancing synaptic and longevity gene expression.

neuroscience↗

bioRxiv2024

Role of socioeconomic factors and interkingdom crosstalk in the dental plaque microbiome in early childhood caries

Early childhood caries (ECC) is influenced by microbial and host factors, including social, behavioral, and oral health. In this cross-sectional study, we analyzed interkingdom dynamics in the dental plaque microbiome and its association with host variables. The samples collected from the preschool children underwent 16S rRNA and ITS1 rRNA gene sequencing. The questionnaire data were analyzed for social determinants of oral health. The results indicated a significant enrichment of Streptococcus mutans and Candida dubliniensis in ECC samples, in contrast to Neisseria oralis in caries-free children. Our interkingdom correlation analysis revealed that Candida dubliniensis was strongly correlated with both Neisseria bacilliformis and Prevotella veroralis in ECC. Additionally, ECC showed significant associations with host variables, including oral health status, age, place of residence, and mode of childbirth. This study provides empirical evidence associating the oral microbiome with socioeconomic and behavioral factors in relation to ECC, offering insights for developing targeted prevention strategies. HIGHLIGHTSO_LICharacterized interkingdom association between cariogenic species of genus Neisseria and Candida C_LIO_LIBoth bacterial and fungal species are important for caries status prediction using artificial intelligence C_LIO_LISocioeconomic index is associated with caries status and caries-associated microbial markers C_LI

microbiology↗

bioRxiv2023

The curious case of cyanobacteria: a tale of light and darkness

Toxic algal bloom-forming cyanobacteria are a persistent problem globally for many aquatic environments. Their occurrence is attributed to eutrophication and rising temperatures due to climate change. The result of these blooms is often loss in biodiversity, economic impacts on tourism and fisheries, and risks to human and animal health. Of particular concern is the poorly understood interplay between viruses and toxic species that form blooms because viruses may exacerbate their harmful effects. Concurrently, cyanobacteria are also a source of bioactive compounds other than toxins, which makes them good candidates for drug discovery. We show that virus infection of the cyanobacterium Microcystis aeruginosa, results in as high as a 40-fold increase in the toxin microcystin two days post virus infection (dpi), and predict that microcystin levels may remain high in a body of water up to 7 dpi, long after water discoloration and cell lysis. This implicates viruses as major contributors to toxin release from cyanobacteria and emphasizes the importance of taking them into account in predictive models and in the assessment of water safety. We also show that bioactive compounds of M. aeruginosa inhibit and delay infection of single stranded DNA and single stranded RNA viruses. This highlights the potential of cyanobacteria as an excellent source for the discovery of novel antiviral compounds, and the ease with which screening for cyanobacterial antivirals can be achieved.

microbiology↗

bioRxiv2022

Effect of insulin insufficiency on ultrastructure and function in skeletal muscle

BackgroundDecreased insulin availability and high blood glucose levels, the hallmark features of poorly controlled diabetes, drive disease progression and are associated with decreased skeletal muscle mass. We have shown that mice with {beta}-cell dysfunction and normal insulin sensitivity have decreased skeletal muscle mass. This project asks how insulin deficiency impacts on the structure and function of the remaining skeletal muscle in these animals. MethodsSkeletal muscle function was determined by measuring exercise capacity and specific muscle strength prior to and after insulin supplementation for 28 days in 12-week-old mice with conditional {beta}-cell deletion of the ATP binding cassette transporters ABCA1 and ABCG1 ({beta}-DKO mice). Abca1 and Abcg1 floxed (fl/fl) mice were used as controls. RNAseq was used to quantify changes in transcripts in soleus and extensor digitorum longus muscles. Skeletal muscle and mitochondrial morphology were assessed by transmission electron microscopy. Myofibrillar Ca2+ sensitivity and maximum isometric single muscle fibre force were assessed using MyoRobot biomechatronics technology. ResultsRNA transcripts were significantly altered in {beta}-DKO mice compared to fl/fl controls (32 in extensor digitorum longus and 412 in soleus). Exercise capacity and muscle strength were significantly decreased in {beta}-DKO mice compared to fl/fl controls (p = 0.012), and a loss of structural integrity was also observed in skeletal muscle from the {beta}-DKO mice. Supplementation of {beta}-DKO mice with insulin restored muscle integrity, strength and expression of 13 and 16 of the dysregulated transcripts in and extensor digitorum longus and soleus muscles, respectively. ConclusionsInsulin insufficiency due to {beta}-cell dysfunction perturbs the structure and function of skeletal muscle. These adverse effects are rectified by insulin supplementation.

physiology↗

bioRxiv2022

H3K36M provokes cellular plasticity to drive aberrant glandular formation and squamous carcinogenesis

Epigenetic dysregulation is pervasive in cancer, frequently impairing normal tissue development and differentiation1. Beyond alterations in histone modifying enzymes, "oncohistone" mutations have been described across a variety of cancers2-4, although the in vivo effects and underlying mechanisms behind these observations have not been well- studied and remain unclear. Here, by inducing the in vivo expression of histone H3.3 carrying a lysine to methionine (K to M) mutation at position 36 (H3K36M) in self- renewing stratifying epithelial tissues, we show that the H3K36M oncohistone dramatically disrupts normal epithelial differentiation, leading to extensive tissue dysplasia characterized by a significant increase in mitotic, proliferative basal stem cells. Furthermore, this differentiation blockade promotes increased cellular plasticity and enrichment of alternate cell fates, and in particular the aberrant generation of excessive glandular tissue including both hypertrophic salivary, sebaceous, and meibomian glands. Upon carcinogen stress, H3K36M mice display markedly enhanced squamous tumorigenesis. These aberrant phenotypic and gene expression manifestations are associated with global loss of H3K36me2 and concomitant gain of H3K27me3. Collectively, these results have revealed a previously unknown critical role for H3K36 methylation in both the in vivo maintenance of proper epithelial cell fate decisions and the prevention of squamous carcinogenesis. Additionally, they suggest that H3K36 methylation modulation may offer new avenues for the regulation of numerous common disorders driven by over- or under-active glandular function.

cancer biology↗

bioRxiv2021

Eukaryotic translation initiation factor eIF4E-5 is required for spermiogenesis in Drosophila melanogaster

Drosophila sperm development is characterized by extensive post-transcriptional regulation whereby thousands of transcripts are preserved for translation during later stages. A key step in translation initiation is the binding of eukaryotic initiation factor 4E (eIF4E) to the 5 mRNA cap. Drosophila has multiple paralogs of eIF4E, including four (eIF4E-3, -4, -5, and -7) that are highly expressed in the testis. Other than eIF4E-3, none of these has been characterized genetically. Here, using CRISPR/Cas9 mutagenesis, we determined that eIF4E-5 is essential for male fertility. eIF4E-5 mutants exhibit defects during post-meiotic stages, including a fully penetrant defect in individualization, resulting in failure to produce mature sperm. eIF4E-5 protein localizes to the distal ends of elongated spermatid cysts, where it regulates non-apoptotic caspase activity during individualization by promoting local accumulation of the E3 ubiquitin ligase inhibitor Soti. eIF4E-5 mutants also have mild defects in spermatid cyst polarization, similar to mutants affecting the cytoplasmic polyadenylation-element binding protein Orb2 and atypical protein kinase C (aPKC). Our results further extend the diversity of non-canonical eIF4Es that carry out distinct spatiotemporal roles during spermatogenesis. Summary StatementThe testis-enriched translation initiation factor eIF4E-5 is needed for spermatid cyst polarization, individualization of mature sperm and male fertility in Drosophila.

developmental biology↗