Biology subjects

Jackson, J.

Publications and source records attributed to Jackson, J..

At least 19 recordsLinked to original sources

bioRxiv2026

Reverse engineering Lewy bodies suggests alpha-synuclein pathology as condensatopathy

Understanding how soluble monomeric alpha-synuclein transitions into pathological alpha-synuclein (Lewy bodies) has remained a central challenge in neurodegeneration. Existing models, largely based on treating cells and animals with pre-formed alpha-synuclein fibrils cannot account for the emergence of the first inclusion without pre-existing seeds. Here, we combine in vitro reconstitutions, computational modeling and a minimal cellular system to show that phase separation of alpha-synuclein with an interacting scaffold can recapitulate Lewy body-like structures. An unbiased proteomics screen, live-cell imaging, correlative light-electron microscopy, and soft X-ray tomography show that Lewy body-like structures are associated with redistribution of actin and membrane-bound organelles, with mitochondria accumulating at their periphery in an actin-dependent manner. Structural analyses further indicate that alpha-synuclein condensates provide local environments in which the insoluble beta-sheets can form. Together, these findings support a seed-independent trajectory from soluble alpha-synuclein through condensation and progressive immobilization to Lewy body-like assemblies and, subsequently, insoluble beta-sheet fibrils. This framework offers a new mechanistic route for understanding the disease progression and promises to guide the design of innovative therapeutic interventions.

neuroscience↗

bioRxiv2026

Claustral pathway coordinates distributed cortical dynamics with hippocampal output during sleep to promote memory consolidation

The claustrum is a broadly connected subcortical structure proposed to coordinate distributed cortical activity. Claustral neurons are recruited during synchronized brain states and contribute to sleep-dependent memory consolidation, primarily through effects on cortical dynamics. Yet the claustrum also innervates the subicular complex, a major hippocampal output node, raising the possibility that it may regulate both cortical state and hippocampo-cortical dialogue during sleep. Here, we identify a projection-defined population of claustral neurons targeting the subicular complex, CLAsc, that is preferentially recruited during slow-wave sleep and tracks cortical and subicular sleep dynamics. Optogenetic activation of CLAsc neurons during post-learning sleep enhanced spatial memory consolidation without detectable changes in ripple occurrence or slow-oscillation-spindle coupling. Instead, CLAsc activation imposed a stereotyped cortical-subicular motif: a brief gamma-rich Up state followed by a coordinated Down state across prefrontal, retrosplenial and subicular regions. Within this gamma-rich Up state, interareal coherence increased, gamma bursts became synchronized, and lagged directed interactions were transiently reorganized, including an enhanced prefrontal-to-subicular component. Together, these findings identify the claustrum as a state-dependent coordinator that transforms ongoing cortical and hippocampal-output activity into coordinated network transitions during sleep, providing a circuit mechanism through which distributed brain states may support memory consolidation.

neuroscience↗

bioRxiv2026

An Integrated Spatially Resolved Mechanistic Model of Hierarchical Auxin-Cytokinin-Ethylene Crosstalk Underlying Root Growth Inhibition in Arabidopsis

Decoding how plants integrate multiple hormone signals to coordinate growth requires tools capable of resolving pathway interactions at cellular resolution in living tissue. Here we present ACE (Auxin-Cytokinin-Ethylene) and ACE2, proof-of-concept single-locus reporters to simultaneously capture activity of multiple hormones. Deploying ACE alongside well-established reporters, exogenous hormone treatments, and reverse-genetic perturbations of hormone biosynthesis, signaling, and transport in three-day-old etiolated Arabidopsis seedlings, we dissect the spatiotemporal hierarchy governing primary root elongation and root apical meristem (RAM) size. We demonstrate that both ethylene- and cytokinin-triggered root growth inhibition involve a boost of TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 (TAA1)-mediated auxin biosynthesis and AUXIN RESISTANT1 (AUX1)-dependent auxin redistribution. Two spatially distinct auxin responses underlie the respective root growth effects: ethylene expands TAA1-dependent auxin biosynthesis from the root vasculature into the epidermis and promotes AUX1-mediated auxin import into the transition and elongation zones to inhibit cell elongation, while cytokinin confines ethylene-dependent TAA1-boosted activity to the vasculature and drives auxin accumulation in lateral root cap cells to reduce RAM size. Together, these data establish a reciprocal regulatory loop between these hormones, positioning ethylene as a convergence node in auxin-cytokinin crosstalk, and cytokinin as a modulator of the ethylene-auxin interaction. Critically, the changes in cross-activated reporter patterns described for different genetic backgrounds, alongside quantitative assessment of hormone-specific inhibition of the mutants growth, were consistent with the multi-hormone network established over two decades of research, and added cell-type-resolved spatial detail and a proposed hierarchy for the etiolated seedling root. Finally, a second-generation reporter, ACE2, overcomes key technical limitations of ACE, expanding the platforms capacity toward a higher-order multi-hormone monitoring system. These resources expand the Arabidopsis genetic toolkit and provide a generalizable framework instrumental for dissecting multi-hormone signaling hierarchies at the cellular level.

plant biology↗

bioRxiv2026

SSR42 Enhances the Hemolytic Capacity of Staphylococcus aureus by Stabilizing the hla mRNA

Staphylococcus aureus utilizes a complex regulatory network to precisely control a vast array of virulence factors and facilitate infection. One such regulator, the long regulatory RNA SSR42, is emerging as a key modulator of virulence factor abundance and pathogenesis. Previous work has shown that a primary role for SSR42 is controlling hemolytic behavior through the positive regulation of -toxin (hla/Hla). Herein, we confirm that loss of SSR42 limits hemolytic capacity due to reduced Hla production. Others have suggested that this occurs through the SaeRS two-component system; however, using epistasis experiments, we reveal that SSR42 and SaeRS function independently to control Hla activity. Using a two-plasmid system optimized to detect regulatory RNA-mediated control in Gram-positive bacteria, we demonstrate that SSR42 directly enhances Hla production through the hla 5 untranslated region. Using interaction prediction and targeted mutagenesis, we identify a discrete site upstream of the hla ribosome-binding site that is required for SSR42 binding and hemolytic activity. Transcriptional arrest experiments further show that SSR42 stabilizes the hla mRNA, increasing its half-life and promoting downstream toxin production. Finally, electrophoretic mobility shift assays confirm a specific interaction between SSR42 and the hla 5 UTR. Collectively, these findings establish SSR42 as a major post-transcriptional regulator of S. aureus virulence and reveal a novel RNA-mediated mechanism that promotes -toxin production through stabilization of the hla transcript.

microbiology↗

bioRxiv2026

Megaherbivore mortality risk from temperature extremes is buffered by vegetation productivity but amplified by rainfall

Demographic risks from climate change remain poorly understood for megaherbivore species which face unique challenges because their large food requirements impose strong bottom-up limitation while their small surface-area-to-volume ratio limits heat dissipation. Here, we test how megaherbivore mortality is shaped by the concurrent effects of temperature and rainfall along with vegetation productivity, a potentially critical modifier of climate effects. By analysing four decades of monthly mortality records from 4,457 semi-captive Asian elephants across Myanmar, we identify multiple environmental pathways regulating megaherbivore mortality. Elephant mortality increased at extreme hot and cold temperatures in regions with low annual vegetation productivity, whereas high vegetation productivity buffered against such U-shaped effects of temperature. Furthermore, high rainfall amplified the negative impacts of extreme heat, underlining risks arising from the joint effects of heat and humidity. Seasonal declines in vegetation productivity did not explain the elevated mortality at temperature extremes. Together, our findings show that megaherbivores face elevated risks from global warming, but such risks strongly depend on vegetation productivity and humidity, highlighting multiple pathways through which climate change can shape the dynamics of megaherbivore populations.

ecology↗

bioRxiv2026

Multi-point convective delivery overcomes mass transport barriers for myocardial therapeutics

Angiogenesis-promoting macromolecules reduce adverse remodeling and preserve cardiac function in rodents following myocardial infarctions, yet repeatedly fail to translate across length scales in humans. Through mass transport studies in human and swine myocardium, we found that dense, anisotropic myocardial fibers limit therapeutic diffusion and convection to millimeter scales for existing approaches including bolus intramyocardial injections, shear-thinning hydrogels, and epicardial patches. Furthermore, distributions are confined to one dimension along fibers. To increase myocardial drug distribution to centimeter length scales in vivo in swine, we engineered a three-dimensional multi-injection drug delivery array. Our device performs up to 40 simultaneous 120 {micro}L injections of functional macromolecules, hydrogels, or mRNA lipid nanoparticles. Injections are precisely placed in relation to fiber alignment, achieving near-complete coverage of the left ventricular myocardium.

bioengineering↗

bioRxiv2026

An integrated single cell and spatial omics atlas of human prenatal development

Single cell genomics has enabled analysis of human prenatal development at unprecedented resolution. However, most studies have relied on dissociated tissues during restricted windows of development, limiting insights into how spatially distributed networks of cells, and multicellular niches emerge and adapt to distinct organ microenvironments in situ. Moreover, existing human developmental atlases have not yet been harmonised, and we thus lack a comprehensive catalogue of known cell types in the developing human body. Here, we introduce the Human Developmental Cell Atlas (HDCA), a unified structural, cellular and molecular resource for prenatal human development. The HDCA integrates published and unpublished single cell/nucleus RNAseq atlases across prenatal organs, and includes a newly generated, spatially resolved, multimodal cell atlas of intact human embryos. Spanning 4-22 post conceptional weeks, capturing embryonic and early to mid fetal stages, the HDCA contains [~]4.6 million cells/nuclei which resolve into [~]450 cell types, explorable with a bespoke web portal. For a global overview of the human embryos multicellular communities, we applied unsupervised deep learning to our intact human embryo spatial data, charting 114 tissue niches that are structural and signalling hubs for the cellular interactions of the embryo. Guided by these niches, we profiled cellular networks over space and time, not examinable using single-organ atlases. In so doing, we revealed tissue-specific fibroblast patterning from previously undescribed mesenchyme progenitors, early diversification of organ-specific blood capillaries and lymphatic vasculature, emergence of neural crest cell fates, the formation of placode-and neural crest-derived peripheral sensory neurons, and how tissue niches guide peripheral neuron maturation and axonal migration. The HDCA thus serves as a comprehensive step towards a comprehensive understanding of human prenatal development, and a template towards unravelling the biology of congenital disorders.

developmental biology↗

bioRxiv2026

Self-severing circuits facilitate passage of ingestible electronic sensor-guided therapeutics

Ingestible electronics enable the tracking and treatment of gastrointestinal and systemic diseases. However, bulky batteries and circuit boards require large capsules that can result in bowel obstruction, a medical emergency. Here, we engineered a 9 x 26 mm electronic pill capable of triggered severing into tiny pieces with sizes clinically proven to reduce obstruction risk. Our capsule enables multicomponent circuit boards to connect with separately encapsulated powering elements via conductive, interlocking connections. Heat induced softening of polyethylene glycol/polycaprolactone channels activates a spring to separate encapsulated components into inert 9 x 15 mm segments, facilitating intestinal passage. Separation triggers included closed-loop sensors and time-delay circuits. In vivo swine studies demonstrate the ability of our capsules to sense luminal oxygen changes via an optoelectronic sensor, locally trigger upadacitinib delivery, and facilitate safe excretion.

bioengineering↗

bioRxiv2026

The BRCA1-A complex restricts replication fork reversal-dependent DNA repair in ATM deficient cells

Ataxia Telangiectasia Mutated (ATM) kinase deficiency results in cancer susceptibility and drug sensitivity. Deficiency in either the BRCA1 interacting A complex or XRCC4/Ligase 4 confers resistance to Topoisomerase I or PARP1 inhibitors in ATM-deficient cells. This suggests that BRCA1-A directs toxicity to fork-damaging agents in ATM mutated cells vis-a-vis illegitimate end-joining. Here, we show that ATM inhibition triggers combined SUMO and ubiquitin mediated BRCA1-A damaged fork recognition to restrict end-resection and cause Topoisomerase I inhibitor hypersensitivity. BRCA1-A deficient cells display elevated chromatin accessibility and nuclease activity at damaged forks, coupled with restored resection and drug resistance. Electron microscopy evidence demonstrates that ATM inhibition prevents replication fork reversal, which is restored by BRCA1-A loss to generate substrates for end resection. These findings reveal that BRCA1-A enforces a restrictive chromatin state to suppress the genesis of resection substrates, implicating fork reversal as a key determinant of chemotherapy response in ATM deficient cells.

cell biology↗

bioRxiv2026

Hormone signaling and immune programs define differential endocrine responsiveness in high-risk breast tissue

Hormone therapies are frequently used to reduce breast cancer risk in individuals at increased risk for primary or subsequent disease; however, tissue-level responses to these therapies are heterogeneous and incompletely understood. Background parenchymal enhancement (BPE) on breast magnetic resonance imaging (MRI) provides a non-invasive radiologic readout of breast tissue features associated with endocrine responsiveness and cancer risk. Although BPE is associated with hormonal exposure, a subset of patients with BPE do not show a response to preventive endocrine therapy and therefore may remain at increased breast cancer risk. In this study, we integrated single-nucleus RNA sequencing and spatial transcriptomics to define the determinants of endocrine responsiveness in the setting of BPE. We identify hormone-driven epithelial cells with high levels of estrogen signaling and endocrine responsiveness, together with immune-associated epithelial programs characterized by diminished luminal identity and increased expression of immune-modulatory pathways, including major histocompatibility complex (MHC) class II and CD74. Functional organoid assays validate that these epithelial states exhibit differential sensitivity to tamoxifen and demonstrate that inflammatory signals can induce immune-modulatory epithelial programs. Together, our findings identify hormone signaling and immune programs as key determinants of endocrine responsiveness in breast tissue and provide a biological basis for interpreting radiologic markers relevant to cancer prevention.

cancer biology↗

bioRxiv2025

FET proteins and PARylation-dependent condensates promote replication fork reversal and genome stability

Targeting replication-associated DNA repair mechanisms, including those regulated by PARP1/2 and PARG control of ADP-ribosylation is a powerful cancer therapeutic approach. However, the mechanisms by which PARG inhibition impacts DNA replication remain unclear. Here we combined isolation of proteins on nascent DNA (iPOND) with quantitative proteomics and functional assays to investigate replication fork dynamics upon acute PARG inhibition. We found that FET family proteins (FUS, EWS, and TAF15) are recruited to replication forks in a PAR-dependent manner, forming condensates that slow fork progression and promote fork reversal. FET proteins control fork dynamics in response to some, but not all, replication stresses. FUS inactivation leads to unrestrained fork progression via RECQ1 and PRIMPOL, increased single-stranded DNA gaps, genome instability, and synthetic lethality with BRCA1 deficiency. These findings reveal that FET protein condensates modulate replication stress responses, influencing genome stability and the cellular response to cancer therapeutics targeting PARylation pathways.

molecular biology↗

bioRxiv2025

Opioid receptor distribution in the claustrum-dorsal endopiriform complex

The claustrum and dorsal endopiriform regions form a thin subcortical sheet reciprocally connected to the neocortex that is enriched in opioid receptors. The precise cellular distribution of opioid receptors within this region remains unclear. Using multiplexed fluorescence in situ hybridization (mFISH) and hierarchical cluster analysis, we mapped the expression of mu (Oprm), delta (Oprd), kappa (Oprk), and ORL1 (Oprl) opioid receptor genes at single-cell resolution in the mouse claustrum-dorsal endopiriform. Among 2,269 neurons analyzed, six transcriptional clusters were identified: three excitatory (CLA, CLA/OPRK, cortical excitatory) and three inhibitory (SST, PVALB, broad inhibitory). Oprk expression was uniquely restricted to excitatory claustrum neurons and particularly enriched in the CLA/OPRK cluster which was comprised largely of Synpr+ claustrum core projection cells. In contrast, Oprd, Oprm, and Oprl genes were more broadly distributed across both excitatory and inhibitory populations, with Oprd enriched in parvalbumin (Pvalb) inhibitory neurons and Oprl in somatostatin (Sst) inhibitory neurons. Spatial mapping confirmed that Oprk expressing cells were concentrated within the claustrum core, whereas other receptor subtypes extended across the entire claustrum and into adjacent cortical regions. A comparable distribution of opioid receptors was observed in the neighbouring dorsal endopiriform. Analysis of a publicly available single cell sequencing dataset of the macaque claustrum also revealed a similar receptor distribution, where Oprk expression was enriched within a subset of excitatory projection neurons, and Oprm,Oprd, and Oprl expressed widely in both inhibitory and excitatory cells. Together, these findings demonstrate an evolutionarily conserved, cell-type-specific organization of opioid receptor expression in the claustrum-dorsal endopiriform. These results indicate that kappa opioid receptor expression is a defining molecular feature of excitatory claustrum projection neurons and suggest distinct roles for other opioid receptors in modulating inhibitory and cortical circuits.

neuroscience↗

bioRxiv2025

Spatially Mapping the Mechanical and Structural Properties of the Seedling Uterine Fibroid-Myometrium Interface

Uterine fibroids (leiomyomas) are highly prevalent, noncancerous tumors canonically described as stiff and collagen-dense. Still, the mechanical heterogeneity within uterine fibroids and the alterations that occur at the fibroid-myometrium interface remain poorly understood. This study quantitatively maps the local mechanical, structural, and compositional properties of seedling uterine fibroids (< 1 cm) at the interface region. Relative to patient-matched myometrial tissues, uterine fibroids exhibited increased stiffness, decreased permeability, increased diffusivity, decreased hydration, greater collagen content, and distinct collagen organization. At the fibroid-myometrium interface, a band of aligned myometrial fibers immediately adjacent to the fibroid was observed, and heterogeneous spatial patterns in elastic modulus and permeability were identified. Ultimately, this study establishes foundational knowledge on the mechanics and structure of seedling uterine fibroids, facilitating future developments of clinically translatable detection tools.

bioengineering↗

bioRxiv2025

The anterior cingulate cortex drives lateralized age-dependent modulation of claustrum circuits

The anterior cingulate cortex (ACC) sends top-down inputs to the claustrum during sensory, motor, and cognitive processing. This ACC input is thought to drive the activation of claustrum neurons which in turn project back to the cortex to help orchestrate cortical networks during demanding cognitive states such as attention. However, the circuit mechanisms underlying ACC-claustrum signaling are not fully understood. Using in vivo single neuron recordings in mice, we show that ACC neuron activation drives a lateralized modulation of claustrum excitability that changes as a function of postnatal age. In adulthood, ACC activation evoked feed-forward inhibition of ipsilateral excitatory claustrum neurons and activation of contralateral excitatory claustrum neurons. Chemogenetic manipulation in adult mice revealed that ipsilateral claustrum inhibition by the ACC was due to feed-forward activation of claustrum parvalbumin inhibitory neurons. However, in neonatal mice, which lack mature parvalbumin interneurons, ACC inputs evoked claustrum excitation. In juvenile mice, the developmental switch from ACC-evoked claustrum excitation to inhibition occurred in parallel with the maturation of claustrum parvalbumin interneurons, thus corroborating the chemogenetic findings. Therefore, this work provides a novel mechanism of cortical control over claustrum activity that is refined during early postnatal life.

neuroscience↗

bioRxiv2025

Condensin and topoisomerases cooperate to relieve topological stress at stalled replication forks

Resolving complex topological structures at replication forks is vital for successful DNA replication, but the mechanisms are little understood. Evidence from diverse eukaryotes suggests that condensin - which promotes chromosome condensation in M phase - might also act during S phase to facilitate relaxation of torsional stress by topoisomerases. Here, we show in yeast and human cells that condensin binds stressed replication forks, where it cooperates with topoisomerases I and II to promote resection of the nascent DNA and restart replication. Our findings suggest that condensin acts with topoisomerase I at reversed forks to convert positively supercoiled DNA into structures that are subsequently relaxed by topoisomerase 2, allowing the fork to resume replication. These findings uncover an important, evolutionarily conserved role for condensin in handling topological constraints at arrested forks that is reminiscent of its function in chromosome segregation and might prevent formation of toxic chromosome structures during fork arrest and reversal.

genetics↗

bioRxiv2025

Sleep-like Slow Waves During Wakefulness Mediate Attention and Vigilance Difficulties in Adult Attention-Deficit/Hyperactivity Disorder

BackgroundAttention-Deficit/Hyperactivity Disorder (ADHD) is characterised by behavioural variability and heightened inattention associated with increased mind wandering (MW) and mind blanking (MB). Individuals with ADHD frequently experience sleep disorders and excessive daytime sleepiness, suggesting interactions between attention and arousal systems. Research examining brain activity using electroencephalography (EEG) has demonstrated that sleep-like slow waves (SW) during wakefulness are linked to inattention in neurotypical individuals, particularly following sleep deprivation, yet their role in ADHD remains unclear. This study investigated whether individuals with ADHD present with altered waking SW distribution compared to neurotypical controls and whether SW explain attentional difficulties in ADHD. MethodsAdults with (n = 32) and without ADHD (n = 31) completed a sustained attention task while EEG recorded brain activity. Mental state probes (on-task, MW, MB) were embedded within the task. Sleep-like SW reflect a slowing of cortical activity and was detected from EEG activity. Omission/commission errors, reaction time (RT), RT variability, mental state reports and subjective sleepiness were analysed. Mediation analysis examined whether SW density explained ADHD-related performance differences. ResultsIndividuals with ADHD exhibited more commission errors, MW and MB, and higher SW density (SW/min), particularly over parieto-temporal electrodes. Increased SW density correlated with higher omission errors, slower RTs, greater RT variability, and elevated sleepiness ratings. On-task reports were negatively correlated with SW density. Mediation analysis revealed that SW density significantly accounted for ADHD-related attentional difficulties. ConclusionsWake SW may explain attentional difficulties in ADHD, providing a potential mechanistic link between sleep disturbances and attentional fluctuations.

neuroscience↗

bioRxiv2025

Tissue Factor Expression in Penile Squamous Cell Carcinoma: A Marker of HPV-Independent Disease

In a series of 33-patients, we evaluated tissue factor (TF) expression in penile squamous cell carcinoma (PSCC). A tissue microarray (TMA) was constructed with 3 cores per patient tumor (99 total cores). Anti-TF antibody staining was performed by immunohistochemistry and H-scores for membrane and cytoplasm staining were assessed (range 0-300). Percentage of cores and patient tumors staining positive for TF ([≥]10% of tumor cells with at least 1+ intensity in cytoplasm and/or membrane) and H-scores were described and compared with HPV and p16 status. Association of TF expression with tumor grade, presence of metastatic disease, lymphovascular invasion (LVI), perineural invasion (PNI), aberrant p53 expression, recurrence free survival (RFS), and cancer specific survival (CSS) were assessed. Nectin-4 and TROP2 staining and their association with clinical/pathological data was determined in a similar manner. TF staining was more prominent in HPV-negative tumors in both the membrane (H-score 69.6 vs 18.8; p=0.003) and cytoplasm (H-score 59.2 vs. 17.7, p=0.007). Cytoplasmic (H-score 61.7 vs 11.7, p=<0.001) and membrane TF staining (H-score 71.7 vs 15.0, p=<0.001) favored p16 negative tumors. The p53 status was more likely to be aberrant in the higher TF staining samples (cytoplasm H-score 61.7 vs 18.3, p=0.012; membrane H-score 67.5 vs 20.3, p=0.006). We observed an association with TROP2 staining and positive p16 status (membrane H-score 120.3 vs. 85, p=0.052; cytoplasmic H-score 135 vs. 107.5, p=0.041). We observed an association of TROP2 staining with positive LVI (membrane H-score 136.7 vs. 66.7, p=0.014; cytoplasmic H-score 110 vs. 93.3, p=0.04). We found no association between TF, TROP2, or nectin-4 staining with CSS or RFS; however, we suspect that this is due to our small sample size. Our results indicate that TF expression could be positive biomarker for HPV-independent, p53-aberrant PSCC, while TROP2 could be associated with HPV-associated PSCC.

pathology↗

bioRxiv2025

Omega-3 Fatty Acid Synergy with Glucocorticoid in Lupus Macrophages: Targeting Pathogenic Pathways to Reduce Steroid Dependence

IntroductionSystemic lupus erythematosus (SLE) is a complex autoimmune disorder characterized by aberrant inflammation, type I IFN-stimulated gene (ISG) expression, and autoantibody production. Glucocorticoids (GCs) like dexamethasone (DEX) are standard long-term SLE treatments but cause significant side effects, highlighting the need for safer steroid-sparing options. Preclinical and clinical studies suggest that dietary supplementation with omega-3 fatty acids (O3FAs), particularly docosahexaenoic acid (DHA), suppress inflammation and autoimmunity associated with SLE disease progression. We explored the steroid-sparing potential of DHA to influence suppressive effects of DEX on pathogenic gene expression. MethodsMacrophages from SLE-prone NZBWF1 mice were first subjected to DHA (5, 10, or 25 {micro}M), DEX (1, 10, 100, or 1000 nM), or DHA+DEX cotreatment. Following pretreatment, cells were exposed to lipopolysaccharide (LPS; 20 ng/mL) to model SLE hyperinflammation. Effects on gene expression were analyzed by qRT-PCR and RNA-seq. ResultsqRT-PCR indicated that subinhibitory concentrations of DHA (5-10 {micro}M) potentiated the efficacy of low-dose DEX (1-100 nM) in suppressing LPS-induced ISG expression (e.g., Irf7, Oasl1, Rsad2), amplifying the effects of DEX monotherapy by 10- to 100-fold. SynergyFinder analysis confirmed that DHA and DEX interacted synergistically in suppressing ISG expression, with significant inhibition observed at concentrations as low as 1 nM DEX and 5 {micro}M DHA. RNA-seq revealed that combining suboptimal DHA (10 M) and DEX (100 nM) induced 247 differentially expressed genes (DEGs) at 4 hr and 347 DEGs at 8 hr post-LPS, dramatically surpassing the effects of each treatment alone. Functional enrichment analysis indicated that DHA+DEX cotreatment robustly suppressed immune and inflammatory pathways while promoting proliferative and metabolic processes, reflecting a shift from inflammatory (M1) to pro-resolving (M2) macrophage phenotypes. DHA and DEX countered LPS effects by i) downregulating common transcription factors (TFs) canonically associated with inflammation (e.g., NF-{kappa}B, AP-1, STATs, and IRF1), ii) upregulating shared regulatory factors involved in inflammation resolution (e.g., YBX1, EGR1, and BCL6), and iii) selectively influencing other regulatory factors. DiscussionAltogether, DHA and DEX synergistically suppress inflammation by targeting common and unique molecular pathways in SLE macrophages, favoring the pro-resolving M2 phenotype. O3FA-GC cotreatment might facilitate reducing requisite steroid dosages for SLE management.

immunology↗