Biology subjects

Wolf, M.

Publications and source records attributed to Wolf, M..

At least 19 recordsLinked to original sources

bioRxiv2026

The ontogeny of repeatability: measurement choices shape individuality estimates in a clonal fish

Consistent among-individual differences in behavior across time and contexts ("individuality", "animal personality") are increasingly recognized as playing an important role in both the ecology and evolution of species. Such individuality is not static: individual differences emerge, shift, and crystallize across ontogeny, shaped by developmental plasticity, stochastic processes, and gene-environment interactions. Despite growing awareness of this developmental dimension, the field has relied predominantly on snapshot designs with few repeated measures, raising the question of how much reported repeatability estimates reflect biology versus methodological choices. Here, we leverage high-resolution tracking data from 45 clonal Amazon mollies (Poecilia formosa) recorded at 5 frames per second across the first 28 days of life to systematically examine how temporal aggregation, sampling rate, frame rate, and the number and placement of measurement days affect repeatability estimates and their underlying variance components. We find that repeatability increases with higher temporal aggregation, decreases with lower sampling rates, and varies substantially depending on the developmental stage sampled. These results demonstrate that commonly used measurement practices can substantially distort repeatability estimates, and that conclusions about behavioral consistency may be as much a product of study design as of biology. We close with practical recommendations for researchers studying individuality across development.

animal behavior and cognition↗

bioRxiv2026

Carbonic anhydrase inhibition rescues heart function in the Tg2576 Alzheimer's mouse model by ameliorating cardiac amyloid-β pathology and neurotrophic signaling impairment.

FDA-approved carbonic anhydrase inhibitors (CAIs) have shown robust efficacy in reducing amyloid- beta pathology, neurodegeneration, and cerebrovascular dysfunction in Alzheimer disease (AD) and cerebral amyloid angiopathy (CAA) models, highlighting carbonic anhydrases (CAs) as a promising, previously untapped therapeutic target for AD and the vascular contribution to dementia. We have recently shown that amyloid- beta aggregates disrupt neuro-signaling and deplete neurotrophic factors (particularly BDNF) in the heart of AD mouse models and human subjects. In this study, we present the first in-depth examination of CAI therapy (acetazolamide, ATZ) in Tg2576 mice, a well-established model of AD and CAA. We confirm that progressive cardiac fibrosis and amyloid- beta deposition in 13-month-old mice severely impair the cardiac neuro-signaling system, marked by a drastic decrease in BDNF and reductions in adrenergic fibers and regenerating nerve endings (TH and GAP-43 markers), leading to significant declines in ejection fraction and fractional shortening compared to age-matched WT littermates. Critically, this study demonstrates that long-term ATZ treatment in Tg2576 mice significantly reduces cardiac amyloid- beta burden, prevents adverse neuro-signaling remodeling, and restores heart physiological function, as assessed via speckle tracking strain echocardiography. These in vivo findings were corroborated in human cardiomyocytes, in which CA inhibition reduced human amyloid- beta40 oligomer-dependent disruption of CREB signaling, thus preserving BDNF expression. Together, these results reveal a previously unrecognized cardio-neuroprotective role for CAIs in preventing amyloid- beta-induced cardiovascular remodeling and neuro-signaling disruption in the Tg2576-AD model. Given the established benefits of CAIs on cerebrovascular function and cognition, our findings further support advancing repurposing efforts into clinical trials. CAIs such as ATZ could offer a dual-action therapy approach, addressing both the central nervous system and cardiac pathologies associated with AD and, potentially, the systemic effects of amyloidosis.

cell biology↗

bioRxiv2026

Hidden diversity and host specificity of Cladocopium symbionts revealed by phylotranscriptomics in giant sea anemones.

Giant sea anemones form an intricate, metabolically linked symbiosis with anemonefish (genus Amphiprion) and dinoflagellates (family Symbiodiniaceae). While the association between fish and anemone is well documented, the identity and distribution of resident Symbiodiniaceae remains poorly characterized. Here, we used RNA-sequencing of anemone tentacles and post-assembly filtering to recover Symbiodiniaceae sequences from Japanese anemones. Using transcriptome-wide phylogenetic approaches, we identified distinct Symbiodiniaceae strains in seven sea anemone species and four cryptic lineages of Entacmaea quadricolor. Phylogenies of 1300 and 214 nuclear genes resolved relationships among these symbionts with greater sensitivity than traditional molecular markers such as the Internal Transcribed Spacer 2 (ITS2) or partial 28S ribosomal DNA. Marker-based assessments indicate these Symbiodiniaceae as novel and specific to sea anemone hosts. Our transcriptome-wide phylogenies reveal previously undescribed Cladocopium (Clade C) strains associated with giant sea anemones, with symbionts clustering according to host species and lineage. Cophylogenetic analysis revealed significant phylogenetic congruence between anemone and Symbiodiniaceae, indicating a nonrandom association between host and symbiont evolutionary histories. Two sympatric cryptic lineages of E. quadricolor previously identified through host transcriptomics harbor distinct, specific Symbiodiniaceae assemblages. Analysis of genes under positive selection indicates functional divergence between these Symbiodiniaceae; three-dimensional reconstructions of symbiont cells using serial block-face scanning electron microscopy show consistent differences in cellular organization between two strains, further supporting their distinct functional identity. Together, our results uncover a hidden diversity of host-specific Symbiodiniaceae and suggest that cryptic diversification in giant sea anemones is mirrored by diversification of their algal symbionts within this tripartite symbiosis.

evolutionary biology↗

bioRxiv2026

Single-cell characterization of human periodontal ligament (PDL) cells reveals uniformly mesenchymal populations in matched maxilla and mandible pairs from four donors

The periodontal ligament (PDL) is a mechanically active connective tissue whose fibroblasts and resident progenitor cells drive tooth support, remodeling, and regeneration. Although PDL cell populations are known to be heterogeneous, the composition of expanded primary PDL cultures and the extent to which anatomical origin shapes their transcriptome remain incompletely defined. Here we applied single-cell RNA sequencing to cultured primary PDL cells isolated from matched upper (maxilla) and lower (mandible) jaw sites of four donors, yielding 43,423 cells that were integrated across donors and analyzed by unsupervised clustering. The expanded cultures were uniformly mesenchymal and fibroblastic, essentially devoid of endothelial and immune signatures, and resolved into ten functionally distinct fibroblast substates rather than discrete cell types, including proliferating, collagen- and extracellular-matrix-high, contractile, and progenitor-like populations. Donor identity was the dominant source of transcriptional variation, with several substates restricted to individual donors. A donor-controlled comparison of maxilla versus mandible revealed only a small set of differentially expressed genes, headed by craniofacial positional-identity transcription factors (PITX1 higher in the mandible; BARX1, ALX1, and NKX6-1 higher in the maxilla), indicating that cultured PDL cells retain embryonic positional memory. In contrast, curated wound-healing gene modules did not differ significantly between jaws, and the transcriptional data therefore did not support the clinical impression of faster healing in the maxilla, suggesting that the healing asymmetry more likely reflects vascular, mechanical, and inflammatory signaling factors acting beyond the steady-state transcriptome. These findings characterize the cellular composition of expanded PDL cultures and identify positional identity as the principal jaw-dependent transcriptional feature.

genomics↗

bioRxiv2026

Understanding cryptic diversity within the honeypot ant species complex of Myrmecocystus mendax

Cryptic species diversity, overlooked due to extreme morphological similarity, is a common phenomenon among ants. The "honeypot ant" genus Myrmecocystus (Wesmael, 1838; Formicinae: Lasiini) likely features multiple cryptic species, as previously suggested by phylogenetic studies based on ultraconserved elements (UCEs). Here, this work is expanded upon by examining 140 specimens and 2,508 UCE loci, with a particular focus on the M. mendax species complex from the southwestern USA and northern Mexico. Phylogenomic and population genomic analyses revealed five distinct M. mendax-like lineages and identified two potential cases of cryptic species diversity, one within samples matching the morphology of M. mendax and another within samples conforming to M. placodops. Most specimens morphologically identified as M. mendax formed a well-supported monophyletic group sister to M. melliger assigned individuals, with evidence for ongoing hybridization between both species in the Madrean Sky Islands along the USA-Mexico border. Patterns in the main M. mendax clade also suggest adaptive divergence across ecological gradients, warranting further investigation. Overall, these findings highlight the power of UCE-based genomic data in phylogenetic reconstructions and population genetic analyses to better resolve cryptic species diversity, and clarify complex evolutionary histories shaped by introgression and incomplete lineage sorting.

genomics↗

bioRxiv2026

Non-genetic inheritance of stochastically induced behavioral individuality in a naturally clonal fish

The study of among-individual phenotypic variation arising in the apparent absence of genetic and environmental differences has recently emerged as a rapidly growing research area. Despite growing recognition of its existence and fitness relevance, it remains unknown whether signatures of such presumably stochastically induced variation can be transmitted across generations. To address this knowledge gap, we performed a two-generation behavioral screening with a naturally clonal fish: 34 genetically identical mothers and their 232 offspring were separated after birth into near-identical environments, with early-life behavior being tracked continuously at high resolution, constituting a total of ~19,000 observation hours. We find consistent among-individual differences in behavior (i.e., activity and feeding patterns) in both mothers and offspring. Mother behavior correlates with offspring activity (but not offspring feeding): mothers that spend more time feeding produce more active offspring. We find no evidence of body size (maternal or offspring) mediating mother-offspring behavioral associations. Our study provides first evidence for the non-genetic transmission of among-individual phenotypic differences that arise in the apparent absence of genetic or environmental differences, highlighting the potential importance of this variation for evolutionary processes and the adaptive potential of populations.

animal behavior and cognition↗

bioRxiv2026

Oncodevelopmental plasticity of the skeleton in myeloid neoplasms

Myelofibrosis in patients with myeloproliferative neoplasms (MPNs) is traditionally characterized by bone marrow fibrosis and osteosclerosis, with de novo bone formation commonly attributed to impaired osteoclast-mediated resorption. Here, we challenge this paradigm by demonstrating that a solitary clonal driver mutation simultaneously induces pathological bone formation and resorption, with osteosclerosis acting to conceal localized and active bone destruction rather than inhibiting it. Through population analysis; clinical imaging; patient-derived multi-tissue sequencing; murine models and organ-on-a-chip systems, we demonstrate that spatial and ontogeny-dependent remodeling in mesoderm- and neural crest-derived bones is mechanistically interconnected via a previously unidentified osteochondral stromal injury program. Neural crest-derived stromal cells suppress osteogenic programs and undergo injury-induced lineage plasticity with ectopic chondrogenesis, mirroring pathological remodeling in mesoderm-derived growth plate regions. This shared injury response promotes osteoclastogenesis and is mediated by a conserved Thrombospondin 1+ (THBS1+) stromal population that links fibrotic remodeling to bone loss. Combined pharmacological inhibition of THBS1 and JAK signaling reduces myeloproliferation, halts fibrosis progression, and restores two developmentally distinct bones, establishing THBS1 as a unifying therapeutic target in myelofibrosis.

cancer biology↗

bioRxiv2026

Systematic drug profiling across BAF complex perturbations reveals distinct dependencies

Chromatin remodeling by BAF complexes regulates access to DNA with implications in transcription, replication and the sensing and repair of DNA lesions, processes that are closely coupled to cell growth control. BAF complexes exist in three major subtypes each composed of a unique subset of about a dozen subunits. While for individual BAF subunits direct functions in DNA repair and cell growth have been described, we lack a more systematic interrogation of BAF perturbation and its implications in these processes. To fill this need, we subjected an isogenic BAF knockout collection to treatment with diverse genotoxic and cytotoxic compounds quantifying proliferation, cell cycle phase distributions, cell fate decisions, DNA double-strand break signaling, and transcriptional responses. The screen uncovered vulnerabilities of selected BAF-deficient cells to MEK and EGFR pathway inhibition, as well as unexpected resistance toward checkpoint inhibitors and certain DNA-damaging agents. Notably, loss of distinct ARID paralogs produced markedly divergent phenotypes, indicating limited functional redundancy and subtype-specific contributions to genome stability and cell cycle regulation. Collectively, these results provide a comparative resource linking BAF complex composition to genotoxic and cytotoxic stress responses, highlighting candidate synthetic-lethal interactions and generating hypotheses for mechanistic studies of BAF complexes in genome maintenance and cell growth control.

molecular biology↗

bioRxiv2026

Activity during the first days of life predicts lifespan in a naturally clonal vertebrate

Lifespan varies widely among individuals, yet the extent to which such variation persists when genetic and environmental differences are minimized remains unclear. Here we quantify such stochastic lifespan variation in a naturally clonal vertebrate and test whether and how this variation is linked to early-life behavioral individuality. We followed N = 33 genetically identical Amazon mollies (Poecilia formosa), separated on day 1 of their life into highly standardized environments, from birth to death. Despite genetic uniformity and environmental standardization, lifespan varies markedly, spanning 502 - 826 days. Continuous high-resolution behavioral tracking during the first four weeks of life reveals that seemingly stochastic early-life activity differences explain 32.5% of this variation. Higher activity predicts shorter lifespan during the first two weeks, but as activity levels and among-individual variation in activity decline over early development, a U-shaped relationship emerges, with both low- and high-activity individuals outliving those with intermediate activity. These findings show that signatures of lifespan emerge within days of birth, even among genetically identical individuals, highlighting developmental stochasticity and early-life contingencies as major contributors to variation in life-history outcomes.

animal behavior and cognition↗

bioRxiv2026

Group-level phenotypes are idiosyncratic yet unpredictable over development in a clonal fish

Behavioral differences among groups can have profound impacts on individual fitness, yet how group-level phenotypes arise and change during development is poorly understood. Group-level differences may originate from genetic differences or subtle variation among individuals, but they can also emerge over time through social feedback mechanisms within and between groups, potentially producing dramatically different group-level behavior. Disentangling these drivers of group phenotypes is challenging because groups are typically studied after they are already well established. Using the naturally clonal Amazon molly, we establish replicate groups of genetically identical individuals and continuously track group-level behavior from birth throughout the first 55 days of life. This design allows us to control for genetic and environmental sources of variance, thereby establishing a null baseline for group-level differences. Furthermore, by recording over an extended period beginning from day 1 of life, we test whether group phenotypes follow predictable trajectories driven by individual differences or instead diverge due to social feedback during development. We find that average behavioral changes across groups follow predictable patterns during this early developmental phase. In contrast, differences among groups are highly unstable over longer timescales: although groups differ from very early in life, it appears that the rank-order of group-level phenotypes undergoes a shuffling mid-development, around 4-5 weeks of age. These results suggest that distinct processes generate group-level variation across ontogeny, with early differences largely reflecting consistent individual variation; then as individuals mature and become more socially responsive, social feedbacks push groups along divergent, less predictable behavioral trajectories.

animal behavior and cognition↗

bioRxiv2026

TCF1lo CD8 T cells proliferate and persist autonomously in tumors

Cancers develop in humans over months to years, and tumor-specific CD8 T cells (TST) can interact with cancer cells throughout tumorigenesis. Nevertheless, the long-term population dynamics of TST, especially within progressing tumors, are not well understood. A paradigm first established in chronic viral infection and applied to tumors describes a population hierarchy among exhausted T cells. Progenitor/stem-like exhausted T cells, which express the transcription factor T cell factor 1 (TCF1), maintain the population through self-renewal and by giving rise to terminally differentiated TCF1lo progeny. This has led to a focus on TCF1hi T cells, and though TCF1lo CD8 T cells are the predominant tumor-infiltrating/tumor-reactive subtype in patients, they have been largely overlooked. We leveraged our autochthonous liver cancer model to analyze TST differentiation and proliferation throughout tumorigenesis. Dual EdU/BrdU labeling studies revealed that throughout tumorigenesis, a subset of TCF1lo TST in the liver stochastically entered and exited cell cycle, and at later time points there was no evidence of a TCF1hi progenitor-like population. Moreover, TCF1-knockout TST proliferated and persisted robustly in tumors. Using liver cancer and melanoma models, we showed that tumor-resident TCF1lo TST proliferate and persist autonomously, even when new TST influx into tumors is inhibited. The prevailing notion is that only TCF1hi TST self-renew but we now demonstrate, using a clinically relevant mouse cancer model, that TCF1lo TST stochastically proliferate to achieve long-term population maintenance. Future studies to understand and harness this mechanism to improve T cell persistence in tumors could lead to novel immunotherapies for patients with cancer. SYNOPSISWe show that tumor-specific T cells with little/no expression of TCF1, previously considered incapable of self-renewal, can proliferate stochastically and persist long-term. As TCF1lo CD8 T cells are often the predominant tumor-reactive T cells found in tumors, future studies should be aimed at reprogramming these proliferating T cells within tumors.

immunology↗

bioRxiv2025

Species delimitation using genome-wide estimates of Dxy and Fst

Accurate and stable species delimitation is essential for effective nature conservation and management. Advances in genomics now offer the potential for consistent decision-making. We performed a meta-analysis of genomic data from hundreds of sister lineages of large mammals to test whether species boundaries can be identified using genome-wide sequence dissimilarity estimates. We find that a combined threshold of absolute (Dxy = 0.225% [0.20%-0.27%]) and relative genetic distance (Fst = 0.26 [0.19-0.54]) predicts current taxonomic status with over 90% accuracy. This predictive power indicates that mammalian taxonomists managed to maintain consistency across taxa despite having to rely on disparate morphological traits. Lineage pairs exhibiting Haldanes Rule exceed far higher thresholds (Dxy = 0.4%; Fst = 0.55), implying that mammalian taxonomists adhere to species concepts which allow for interbreeding. Our findings challenge the significance of fast-track bottleneck speciation and suggest instead that deep divergences of up to 100,000 generations are usually required for mammalian sister lineages to remain genetically isolated upon secondary contact. We discuss taxonomic revisions to improve temporal banding, including three potential cases of cryptic speciation: southern versus eastern aardwolves, Asiatic black bears versus Japanese black bears, and European versus Asian wild boar. In summary, our meta-analysis provides simple rules for species delimitation and offers new insights into the taxonomy and speciation dynamics of large mammals.

genomics↗

bioRxiv2025

Inflammatory Agonists Modulate the Host Response to Type 2 ECM scaffold Immune Environment and Long-Term Remodeling After Severe Traumatic Injury

The immune system is a vital regulator of tissue repair after trauma and the response to implantable scaffolds for regenerative medicine. Decellularized extracellular matrix (ECM) scaffolds promote tissue integration and remodeling following traumatic injury in part due initiating a pro-reparative Type-2 immune response. However, exogenous soluble inflammatory immune signals can be introduced during scaffold implantation, including microbial products in contaminated surgical fields or during immunotherapy to treat autoimmunity and cancer. It remains largely unknown how such immune mediators modulate the ECM scaffold immune environment and subsequent scaffold remodeling. In the present study, we co-delivered 3 distinct inflammatory immune adjuvants (cyclic di-AMP [CDA], monophosphoryl lipid A [MPLA], and granulocyte colony stimulating factor [GM-CSF]) with small intestinal submucosa (SIS) ECM in a murine volumetric muscle loss injury model, evaluating acute (1 week) and long-term (8-week) immune environments and scaffold remodeling. High parameter spectral cytometry, histologic analysis, and PCR revealed differential potentiation of the ECM scaffold microenvironment. Type 2 immune programs including IL-4, eosinophils, CD4 T cells, and CD206/CD86 macrophage ratios were induced in all ECM groups but attenuated by varying amounts with the CDA and MPLA co-delivery. By 8-weeks, inflammation had largely subsided, and histologically ECM with GM-CSF or MPLA showed the greatest degradation and remodeling into adipose tissue. These findings suggest that early pro-inflammatory compound delivery does not abrogate the ECM immune environment but does attenuate some programs while inducing others. These have long-term effects on scaffold remodeling and should be a consideration for surgical reconstruction in patients receiving immune stimulatory therapies.

immunology↗

bioRxiv2025

A metaproteomics-based meta study of samples from patients with inflammatory bowel disease identifies potential markers for diagnosis and therapy monitoring

Inflammatory bowel disease (IBD) is a chronic intestinal disorder involving recurring inflammation and pronounced microbial dysbiosis. Comprehensive studies with large patient cohorts are required to Identify meaningful biomarker candidates for diagnosing and monitoring IBD. In this large-scale meta-study of over 600 samples based on fecal metaproteomics, our goal was to validate known biomarkers and discover new candidates. We performed bioinformatic reanalysis using the Mascot search engine and MMUPHin for batch effect correction as well as knowledge graph-enhanced data analysis. We identified 59 protein groups that varied primarily due to disease, rather than laboratory conditions. These included Alpha-1-acid glycoprotein, which was not reported in the original studies. Of these groups, 53 were differentially abundant in at least one of the two validation datasets. Additionally, 23 of the successfully validated protein groups, primarily from human neutrophil vesicles, were found to be significantly associated with remission during treatment in an independent dataset. This finding suggests their potential for disease monitoring. Validation in other disease contexts, such as non-alcoholic steatohepatitis, diabetes, and colorectal cancer, revealed the necessity of biomarker panels, because individual biomarkers could only distinguish IBD from specific conditions. Our results demonstrate the effectiveness of metaproteomics meta-analyses in discovering and validating biomarker panels and assessing their specificity for IBD. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/684320v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@18a6617org.highwire.dtl.DTLVardef@1349adaorg.highwire.dtl.DTLVardef@a27044org.highwire.dtl.DTLVardef@78aabe_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2025

NGN2 Expression and Regional Patterning Allow Rapid Differentiation from hiPSCs to DRG-Like Neurons Responsive to Type 2 Cytokines

Itch or pruritus, is a sensation that elicits scratching behaviour and is a major symptom and cause of morbidity in skin diseases such as atopic dermatitis (AD), allergic contact dermatitis (ACD), prurigo nodularis (PN), and urticaria. Itch is often triggered by inflammatory stimuli in the skin including type 2 cytokines such as IL-4, IL-13, and/or IL-31. Several therapies targeting type 2 immune pathways have been developed to treat pruritus; however, itch improvement in many patients remains to be improved. Thus, additional approaches to modulate sensory neuron activity are needed. Ex vivo or even in vitro study of the molecular mechanisms underlying primary sensory neuron activation is challenging since harvesting neurons from dorsal root ganglia (DRG) in patients can only be done from cadavers. Herein, we describe rapid human sensory neurons generation (2 days to precursor cells) by in vitro differentiation of human induced pluripotent stem cells (hiPSC) from simultaneous application of patterning factors with NGN2 overexpression. We show that these hiPSC-derived sensory neurons possess key characteristics of primary sensory neurons. They express key neuronal markers, such as TRKA receptors, TRPV1 and TRPA1 channels, and functionally respond to the TRPV1 agonist capsaicin. In addition, they express key type 2 cytokine receptors such as interleukin (IL)-4R and IL31-R, known to promote itch in AD and PN. Moreover, these cells are functional as our sensory neurons respond to IL-4, IL-13 and IL-31 stimulation. Collectively, these data demonstrate that our protocol generates a phenotypic profile consistent with native somatosensory neurons that can facilitate development of novel approaches to model and treat pruritic disease.

neuroscience↗

bioRxiv2025

Barrier Function of the Extracellular Matrix in AAV Gene Therapy

PurposeThe extracellular matrix (ECM) is a major component of the tissue microenvironment which may pose a barrier to the distribution of AAV in target organs, preventing delivery of therapeutic cargo. We sought to address this potential barrier to AAV gene therapy by furthering our understanding of AAV-ECM interactions. We hypothesized that both the AAV serotype and ECM composition will impact AAV transport and gene delivery. MethodsAAV2, AAV6, and AAV8 viral vectors were fluorescently labeled to allow for visualization of their diffusion through the ECM. Lung, liver, and small intestinal submucosal dECM hydrogels were formulated as models of the ECM with tissue-specific biomolecular content. We then characterized AAV and nanoparticle diffusion within decellularized ECM using fluorescent video microscopy and multiple particle tracking. Additionally, we evaluated AAV transduction in dECM-incorporated 2D and 3D spheroid tissue culture models. ResultsAll AAV displayed reduced diffusivity through ECM as compared to similarly sized nanoparticles. AAV2 diffusion was least affected by the presence of ECM across tissue types as compared to AAV6 and AAV8. AAV transduction in dECM incorporated in vitro models was significantly reduced in both a 2D and 3D setting. ConclusionsThese results suggest binding of AAV to the ECM may decrease their therapeutic effect in target tissues throughout the body. The barrier function of the ECM should be considered in development of AAV for gene therapy applications.

bioengineering↗

bioRxiv2025

PEGylation strategies for enhanced nanoparticle delivery to tumor associated immune cells

Barriers to nanoparticle drug delivery to the tumor microenvironment such as ECM deposition and clearance by the mononuclear phagocyte system have necessitated strategies for more effective tumor penetration. Adding polyethylene glycol (PEG) chains to the surface of nanoparticles (PEGylation) has been widely used to both enhance accumulation at the tumor site and increase blood circulation time. Recent work has also shown that immune cells (e.g. macrophages, dendritic cells, neutrophils) play an important role in the ability of NPs to effectively target and spread within a tumor. PEG chain characteristics such as size and branching affects how nanoparticles interact with tissues; however, it is unclear how PEGylation type affects NP uptake and cellular distribution in the tumor microenvironment. In this study, we evaluated the influence of both linear and branched PEGylation on nanoparticle biodistribution and uptake in tumor cells as well as tumor-infiltrating immune cells. As compared to conventional surface coatings with linear PEG, we show that modifying PEG structure to a branched conformation increases nanoparticle accumulation in the spleen of tumor-bearing mice, primarily due to significantly enhanced uptake by leukocytes. As compared to uncoated particles, we also found that nanoparticles densely coated with linear or branched PEG accumulated to a greater extent in tumors showing [≥]8-fold increases in uptake by tumor-associated macrophages and dendritic cells. These studies provide insight into PEG architecture as a design parameter in nanomedicine that can facilitate the design of more effective cancer therapies. Translational ImpactThis work uncovers immune-mediated mechanisms and design strategies to enhance NP delivery to tumors via PEGylation which provide a foundation for clinical development of cancer therapeutics. The PEGylation strategies described could be readily integrated into clinically relevant nanoparticle delivery systems (e.g. lipid nanoparticles) with minimal effort making this a highly appealing approach to address the current limitations of cancer nanomedicine.

bioengineering↗

bioRxiv2025

No paternal effects in a sperm-dependent, naturally clonal fish

Paternal effects, i.e., effects of males on the phenotypes of their offspring that are not caused by the integration of male genetic material, are increasingly recognized as a potentially significant source of phenotypic variation across taxa - even in the absence of paternal care. Gynogenetic systems, which rely on sperm to trigger embryogenesis without incorporating male genetic material, provide a powerful way to experimentally isolate potential paternal effects from effects caused by the integration of male genetic material; up to now, however, paternal effects remain largely unexplored in these systems. Here, we test for paternal effects in the gynogenetic Amazon molly (Poecilia formosa): a naturally clonal, all-female species with no parental care. Using a highly controlled breeding experiment involving 59 Atlantic molly males (P. mexicana) and 57 Amazon molly females, we generated 169 broods and 2,966 offspring. While males were drawn from a naturally variable stock population, females - next to being genetically identical - were highly standardized for age, size, descent, and developmental experience. We asked whether male identity or body size predicted offspring size - a key offspring phenotypic trait. We also asked whether male identity or body size predicted brood size. While we found substantial variation in both offspring size and brood size, we found no evidence for paternal effects on either trait. Next to providing an experimental test for paternal effects in a gynogenetic system, our results also strengthen the Amazon mollys status as a model species for studying - in a highly controlled fashion - the developmental emergence of phenotypic variation.

animal behavior and cognition↗