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Biology subjects

Miller, L.

Publications and source records attributed to Miller, L..

At least 19 recordsLinked to original sources

Mechano-activated synovial cells instigate OA-like disease progression in the absence of joint injury

While altered tissue mechanics and cellular mechanoactivation accompany osteoarthritis, whether dysregulated mechanotransduction can initiate joint disease remains unclear. Here, we used intra-articular delivery of cell-penetrating TAT-Cre recombinase to locally perturb the actomyosin-Hippo mechanotransduction axis in mice. Deletion of Lats1/2, the negative regulators of the mechanosensitive transcriptional coactivators YAP and TAZ, induced sustained joint hyperalgesia, altered gait, synovial hyperplasia and fibrosis, vascular remodeling, and articular cartilage degeneration in the absence of a destabilizing injury. Single-cell transcriptomics revealed the emergence of Cthrc1+ matrix-remodeling fibroblasts and accumulation of Mrc1+Trem2+ macrophages during this pathological process. Histological analyses showed persistent contractile stromal remodeling and an early macrophage response that partially subsided over four weeks. Conversely, local deletion of Myh9/10, encoding the force-generating heavy chains of non-muscle myosin II, reduced hyperalgesia, synovial lining hyperplasia, alpha-SMA+ cell accumulation, and macrophage infiltration during post-traumatic osteoarthritis (PTOA) pathogenesis. However, this intervention did not detectably reduce cartilage degeneration at eight weeks. These findings establish synovial mechanotransduction as a causal driver of joint disease via immune-stromal remodeling and pain development. In addition, partial suppression of contractility separates symptomatic from structural outcomes in PTOA. Synovial mechanotransduction therefore represents a target for modulating pathological stromal-immune remodeling and joint pain.

pathology↗

Predicting Speech in Noise Perception using Measures of Neural Entrainment

Speech perception ability in a cocktail party environment is highly variable, even for people with clinically healthy hearing. The mechanisms of these differences are poorly understood. A possible reason for these differences could be due to the neural mechanisms of auditory attention. This investigation aims to quantify how well a person is able to neurally entrain to a continuous narrative using a temporal response function (TRF), then evaluate if that TRF measure is correlated with an individual's performance on a selective attention and narrative comprehension task. This was accomplished using a cohort of twenty-five young and healthy listeners who completed speech-in-noise (SIN) perception tasks while their neural activity was recorded with EEG. This EEG data and regressors (speech envelope and gammatone spectrogram) of an auditory stimulus was used to train TRF models. TRF cross validation correlation coefficients were then used in multiple regression models to predict a participant's SIN performance. Task performance had a significant positive relationship with the neural entrainment to an attended stimulus and a negative relationship with the neural entrainment to an unattended stimulus. This was observed with both the selective attention and narrative comprehension measures. The difference of the attended and unattended correlation coefficients were also significantly related to increased task performance. These measures could be a potential biomarker to predict an individual's speech perception in a noisy environment.

neuroscience↗

IL1 blockade attenuates E. coli induced intrauterine inflammation and preterm labor in Rhesus macaques

Intrauterine infection and inflammation are major causes of preterm labor, yet antibiotics alone often fail to prevent preterm birth despite achieving microbial clearance. Interleukin1 (IL1) is a key mediator of intra-amniotic inflammation and functional progesterone withdrawal, processes linked to labor initiation. We tested whether IL1 blockade with the clinically approved IL1 receptor antagonist, anakinra, could reduce inflammation and preterm labor in a Rhesus macaque model of intra-amniotic Escherichia coli infection followed by delayed antibiotic treatment. Here we show that anakinra reduced the incidence of preterm labor by 40% (p=0.07), attenuated inflammation in the fetal membranes and cervix, and preserved progesterone receptor-B abundance in the fetal membranes. These effects were most pronounced in animals protected from preterm labor. Our findings in a relevant model support the translational potential of combining IL1 blockade with antibiotics for infection-associated preterm labor. One sentence summaryRecombinant human IL1 receptor antagonist (anakinra) decreased E. coli infection induced preterm labor and partially decreased intrauterine inflammation in a non-human primate model of inflammation mediated preterm labor.

immunology↗

Confirmation and Transcriptomic Characterization of Glufosinate-ammonium Resistance in Waterhemp (Amaranthus tuberculatus) Populations from Illinois

Glufosinate-ammonium (GA) has been widely used in Midwestern fields, and in recent years a growing number of failures to control waterhemp [Amaranthus tuberculatus (Moq.) Sauer] have raised concerns about the potential evolution of resistance. The goal of this study was to investigate four independent cases of suspected resistance to GA in A. tuberculatus from Illinois using greenhouse, field, and transcriptomics studies. Greenhouse dose-response experiments revealed resistance ratios ranging from 2.2- to 3.4-fold based on survival and from 1.3- to 2.8-fold based on dry biomass relative to a susceptible population. A subsequent field study where one of the populations originated confirmed that twenty percent of treated plants survived the labeled GA field-recommended rate. Screening for other herbicide sites of action revealed that most populations showed reduced sensitivity to atrazine, glyphosate, and imazethapyr, surviving up to three times the field-recommended rates, and to a lesser extent, lactofen and fomesafen. Transcriptomic analysis of plants surviving GA revealed no resistance-associated mutations or differential transcript abundance in the plastidic and cytosolic isoforms of glutamine synthetase. Among the four suspected resistant populations, there were 182 genes differentially expressed relative to two susceptible populations. Different sets of genes were differentially expressed among the populations studied, with only one gene (upregulated relative to two susceptible populations) shared among all four. Many of the differentially expressed genes, including cytochrome P450s, glutathione S-transferases, glycosyltransferases, transporters, and transcriptional regulators, are commonly associated with metabolic resistance. Gene ontology enrichment analyses indicated significant overrepresentation of stress response, defense regulation, and secondary metabolism categories across the populations. Together, these findings provide evidence for the evolution of GA resistance in populations of A. tuberculatus in Illinois. While more in-depth studies are needed to fully characterize the underlying mechanisms, the consistent differential expression of metabolism-related genes and no indication of target-site mechanisms points to a potential metabolic basis for resistance.

plant biology↗

Discovery of chromatin-based determinants of azacytidine and decitabine anti-cancer activity

The DNA-incorporating nucleoside analogs azacytidine (AZA) and decitabine (DEC) have clinical efficacy in blood cancers, yet the precise mechanism by which these agents kill cancer cells has remained unresolved - specifically, whether their anti-tumor activity arises from conventional DNA damage or DNA hypomethylation via DNA methyltransferase 1 (DNMT1) inhibition. This incomplete mechanistic understanding has limited their broader therapeutic application, particularly in solid tumors, where early clinical trials showed limited efficacy. Here, through the assessment of drug sensitivity in over 600 human cancer models and comparison to a non-DNA-damaging DNMT1 inhibitor (GSK-3685032), we establish DNA hypomethylation, rather than DNA damage, as the primary killing mechanism of AZA and DEC across diverse cancer types. In further support of an epigenetic killing mechanism, CRISPR drug modifier screens identified a core set of chromatin regulators, most notably the histone deubiquitinase USP48, as AZA and DEC protective factors. We show that USP48 is recruited to newly hypomethylated CpG islands and deubiquitinates non-canonical histones, establishing USP48 as a key molecular link between the two components of epigenetic gene regulation: DNA methylation and chromatin modification. Furthermore, loss of USP48, which occurs naturally through biallelic deletions in human cancers, sensitized both hematologic and solid tumors to DNMT1 inhibition in vitro and in vivo. Our findings elucidate the epigenetic mechanism of action of AZA and DEC and identify a homeostatic link between DNA methylation and chromatin state, revealing new therapeutic opportunities for DNMT1 inhibitors in solid tumors.

cancer biology↗

Discourse Focus and Memory Encoding: The Role of Trial-Level Alpha Power

The rapid, continuous flow of spoken language places strong demands on attention, and it is thought that listeners meet these demands by predicting when important information will occur and allocating attention accordingly. However, to date there is little direct evidence for the involvement of preparatory attention during language processing. In this study, we investigate preparatory attention during spoken language comprehension by measuring alpha neural activity with EEG, a known measure of temporal attentional preparation. Alpha activity leading up to target words that were either focused or defocused by a preceding discourse question did not vary as a function of focus, challenging the assumption that attention is pre-allocated to the timing of focused words. On the other hand, we found that trial-by-trial fluctuations in alpha activity predicted both the depth of processing and the subsequent memory for new information. Specifically, pre-target alpha modulated a centro-parietal Dm subsequent memory effect for focused words, linking preparatory attention to memory encoding during comprehension. Together, these findings bridge psycholinguistic studies on information structure and cognitive neuroscience research on temporal attention, offering novel insights into the role of alpha activity in attentional dynamics during spoken language processing.

neuroscience↗

Induction of Human Pruriceptors from Pluripotent Stem Cells via Transcription Factors

Pruriception is crucial for defense against external stimuli but can lead to chronic pruritus, a debilitating condition affecting millions worldwide. Our understanding of the cellular and molecular mechanisms behind the sensation of itch has been hindered by the lack of functional human models. Here, we address this limitation by developing a protocol to generate induced pruriceptors (iPruriceptors) from human pluripotent stem cells (hPSCs). We compared two differentiation approaches: a direct method via forced expression of transcription factors (TFs) in hPSCs, and a 2-step process through expression of TFs in hPSC-derived neural crest cells (NCCs). The 2-step protocol proved superior in inducing a transcriptional program that closely resembles that of human pruriceptors. Our optimized protocol employs forced expression of NGN1 and ISL1 to drive differentiation from NCCs into pruriceptors, enhancing the expression of known pruritogen receptors such as IL31RA, which pairs with OSMR, and HRH1. The induction of this transcriptional program leads to functional maturation of iPruriceptors. Accordingly, iPruriceptors exhibit robust responses to itch stimuli and in vivo-like itch pharmacology such as treatment with ABT-317, a JAK1 inhibitor tool compound, similar to those targeting intensive pruritus in atopic dermatitis (AD). Importantly, iPruriceptors can be generated without viral vectors or safe-harbor gene editing, using a PiggyBac-based transfection method that simplifies scalability. Our protocol offers a robust platform for investigating itch biology, modeling chronic pruritus, and enabling high-throughput screening for therapeutic target discovery. HighlightsO_LINGN1 and ISL1 forced expression in NCCs induces rapid differentiation to iPruriceptors C_LIO_LIiPruriceptors share transcriptional profile of primary human pruriceptors C_LIO_LIiPruriceptors have electrophysiological responses to known pruritogens C_LIO_LIiPruriceptors have JAK1-dependent IL-31/-13 responses blocked by ABT-317 C_LI

neuroscience↗

Spatial distance and temporal attentional focus modulate voluntary action preparation and awareness

Peripersonal space (PPS)--the immediate space surrounding the body--modulates perception and motor control. However, its impact on how voluntary actions are initiated and subjectively experienced remains underexplored. Similarly, how directing attention to different phases of an action, such as intention formation versus execution, and anticipating outcomes of an action, modulates the neural readiness for movement, has yet to be fully examined. This study investigates whether spatial proximity, attentional focus, and anticipated action outcomes influence action preparation and action awareness, using a virtual reality adaptation of the Libet clock paradigm during EEG recordings. Neural results reveal that attentional focus and anticipated action outcomes modulate different phases of motor preparation, as indexed by the readiness potential (RP)--a gradual buildup of neural activity preceding voluntary movement. Focusing on decision timing (without subsequent action outcomes) enhances early RP amplitude and decreases the late RP slope, suggesting increased preparatory neural engagement during intention formation. In contrast, focusing on action execution leads to a steeper late RP slope, indicating later and faster motor activity buildup when attention is directed toward movement onset. Anticipating action outcomes increased late RP slope, which was accompanied by the temporal binding effect: when a tone followed the action, both decision and action estimates shifted toward it. Spatial proximity also modulates early RP slope, with a steeper buildup in near versus far space, suggesting facilitated motor preparation within PPS. It further enhances the late RP amplitude when participants focused on their intention to act. Behavioural results show that actions are perceived as occurring earlier when the clock is displayed near compared to far, indicating that PPS influences the temporal perception of action timing. Overall, these findings highlight the dynamic interplay among external spatial context and internal cognitive processes in shaping motor preparation and action awareness. Importantly, a temporal internal attentional focus on intention to act modulates early RP--traditionally considered an unconscious stage of neural readiness. These results contribute to a deeper understanding of how PPS and the locus of attention on specific action phases affect action preparation and awareness, with potential implications for future research on the sense of agency and voluntary action decision making.

neuroscience↗

Gaze-centered spatial coding of touch on a hand-held tool

Humans possess the remarkable ability to project tactile sensations outside their body and onto a hand-held tool that they are using. Despite nearly a century of research, the computations underlying this projection have not been adequately addressed. In the present study, we employed model-driven psychophysics to fill this gap. We hypothesized that tool-based sensory projection involves the remapping of touch from sensory feedback in the hand into an egocentric coordinate system. We first formalized the computational steps underlying tactile remapping. We designed a novel tool-sensing experiment that allowed us to rigorously test this model. In this task, participants contacted an object with a hand-held rod and then judged whether the object was above or below where they were currently looking. This comparison would only be possible if touch on the tool was projected outside the hand. Crucially, both object location and gaze position varied independently, allowing us to characterize the hand-to-space-to-gaze remapping process. Model-based curve fitting provided strong evidence that all participants in our task projected touch outside their body and into gazecentered coordinates. Crucially, the resolution of this projection was similar to what has been found for touch on the body. These findings provide the first step towards characterizing the computations underlying the spatial projection of touch on external objects, highlighting the incredible versatility of the sensorimotor system.

neuroscience↗

TOR and heat shock response pathways regulate peroxisome biogenesis during proteotoxic stress

Peroxisomes are versatile organelles mediating energy homeostasis and redox balance. While peroxisome dysfunction is linked to numerous diseases, the molecular mechanisms and signaling pathways regulating peroxisomes during cellular stress remain elusive. Using yeast, we show that perturbations disrupting protein homeostasis including loss of ER or cytosolic chaperone function, impairments in ER protein translocation, blocking ER N-glycosylation, or reductive stress, cause peroxisome proliferation. This proliferation is driven by increased de novo biogenesis from the ER as well as increased fission of pre-existing peroxisomes, rather than impaired pexophagy. Notably, peroxisome biogenesis is essential for cellular recovery from proteotoxic stress. Through comprehensive testing of major signaling pathways, we determine this response to be mediated by activation of the heat shock response and inhibition of Target of Rapamycin (TOR) signaling. Finally, the effects of proteotoxic stress and TOR inhibition on peroxisomes are also captured in human fibroblasts. Overall, our findings reveal a critical and conserved role of peroxisomes in cellular response to proteotoxic stress.

cell biology↗

Morphological map of under- and over-expression of genes in human cells

Cell Painting images offer valuable insights into a cells state and enable many biological applications, but publicly available arrayed datasets only include hundreds of genes perturbed. The JUMP (Joint Undertaking in Morphological Profiling) Cell Painting Consortium perturbed roughly 75% of the protein-coding genome in human U-2 OS cells, generating a rich resource of single-cell images and extracted features. These profiles capture the phenotypic impacts of perturbing 15,243 human genes, including overexpressing 12,609 genes (using open reading frames, ORFs) and knocking out 7,975 genes (using CRISPR-Cas9). We mitigated technical artifacts by rigorously evaluating data processing options and validated the datasets robustness and biological relevance. Analysis of phenotypic profiles revealed novel gene clusters and functional relationships, including those associated with mitochondrial function, cancer, and neural processes. The JUMP Cell Painting genetic dataset is a valuable resource for exploring gene relationships and uncovering novel functions.

bioinformatics↗

Hope for Others: Research Results from the University of Pittsburgh Rapid Autopsy Program for Breast Cancer

Breast cancer affects 1/8 of women throughout their lifetimes, with over 90% of cancer deaths being caused by metastasis. However, metastasis poses unique challenges to research, as complex changes in the microenvironment in different metastatic sites and difficulty obtaining tissue for study hinder the ability to examine in depth the changes that occur during metastasis. Rapid autopsy programs thus fill a unique need in advancing metastasis research. Here, we describe our protocol and processes for establishing and improving the US-based Hope for OTHERS (Our Tissue Helping Enhance Research and Science) program for organ donation in metastatic breast cancer. As of August 2024, we consented 114 patients and performed 37 autopsies, from which we collected 551 unique metastatic frozen tumor samples, 1244 FFPE blocks, 90 longitudinal liquid biopsy samples and developed 14 patient-derived organoid and 8 patient-derived xenograft models. We report in-depth clinical and histopathological information and discuss extensive new research and novel findings in patient outcomes, metastatic phylogeny, and factors in successful living model development. Our results reveal key logistical and protocol improvements that are uniquely beneficial to certain programs based on identifiable features, such as working closely with patient advocates, methods to rescue RNA quality in cases where tissue quality may degrade due to time delays, as well as guidelines and future expansions of our program. Statement of SignificanceRapid autopsy programs are unique research settings with huge potential for studying metastatic cancer, however, they have complex research challenges. Our work provides a valuable resource in advancing this field of research.

cancer biology↗

Tool use fine-tunes arm and tool maps

There is evidence that the sensorimotor system builds fine-grained spatial maps of the limbs based on somatosensory signals. Can a hand-held tool be mapped in space with a comparable spatial resolution? Do spatial maps change following tool use? In order to address these questions, we used a spatial mapping task on healthy participants to measure the accuracy and precision of spatial estimates pertaining to several locations on their arm and on a hand-held tool. To study spatial accuracy, we first fitted linear regressions with real location as predictor and estimated location as dependent variables. Intercepts and slopes, representing constant offset and estimation error, were compared between arm and tool, and before to after tool use. We further investigated changes induced by tool use in terms of variable error associated with spatial estimates, representing their precision. We found that the spatial maps for the arm and tool were comparably accurate, suggesting that holding the tool provides enough information to the sensorimotor system to map it in space. Further, using the tool fine-tuned the users spatial maps, increasing the precision of the tool map to a greater extent than their arm map. Furthermore, this increased precision is focal to specific tool locations, i.e., the tool tip, which may work as a spatial anchor following tool use. Our results demonstrate that tool users possess dynamic maps of tool space that are comparable to body space.

neuroscience↗

Extending tactile space with hand-held tools: A re-analysis and review

Tools can extend the sense of touch beyond the body, allowing the user to extract sensory information about distal objects in their environment. Though research on this topic has trickled in over the last few decades, little is known about the neurocomputational mechanisms of extended touch. In 2016, along with our late collaborator Vincent Hayward, we began a series of studies that attempted to fill this gap. We specifically focused on the ability to localize touch on the surface of a rod, as if it were part of the body. We have conducted eight behavioral experiments over the last several years, all of which have found that humans are incredibly accurate at tool-extended tactile localization. In the present article, we perform a model-driven reanalysis of these findings with an eye towards estimating the underlying parameters that map sensory input into spatial perception. This reanalysis revealed that users can almost perfectly localize touch on hand-held tools. This raises the question of how humans can be so good at localizing touch on an inert non-corporeal object. The remainder of the paper focuses on three aspects of this process that occupied much of our collaboration with Vincent: the mechanical information used by participants for localization; the speed by which the nervous system can transform this information into a spatial percept; and whether body-based computations are repurposed for tool-extended touch. In all, these studies underscore the special relationship between bodies and tools.

neuroscience↗

Disruption of DLL4/NOTCH1 Causes Dysregulated PPARγ/AKT Signaling in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a progressive cardiopulmonary disease characterized by vascular remodeling of small pulmonary arteries. Endothelial dysfunction in advanced PAH is associated with proliferation, apoptosis resistance, and endothelial to mesenchymal transition (EndoMT) due to aberrant signaling. DLL4, a cell membrane associated NOTCH ligand, activates NOTCH1 signaling and plays a pivotal role maintaining vascular integrity. Inhibition of DLL4 has been associated with the development of pulmonary hypertension, but the mechanism is incompletely understood. Here we report that BMPR2 silencing in PAECs activated AKT and decreased DLL4 expression. DLL4 loss was also seen in lungs of patients with IPAH and HPAH. Over-expression of DLL4 in PAECs induced BMPR2 promoter activity and exogenous DLL4 increased BMPR2 mRNA through NOTCH1 activation. Furthermore, DLL4/NOTCH1 signaling blocked AKT activation, decreased proliferation and reversed EndoMT in BMPR2- silenced PAECs and ECs from IPAH patients. PPAR{gamma}, suppressed by BMPR2 loss, was induced and activated by DLL4/NOTCH1 signaling in both BMPR2-silenced and IPAH PAECs, reversing aberrant phenotypic changes, in part through AKT inhibition. Finally, leniolisib, a well-tolerated oral PI3K8/AKT inhibitor, decreased cell proliferation, induced apoptosis and reversed markers of EndoMT in BMPR2-silenced PAECs. Restoring DLL4/NOTCH1/PPAR{gamma} signaling and/or suppressing AKT activation may be beneficial in preventing or reversing the pathologic vascular remodeling of PAH.

cell biology↗

WCRC-25: A novel luminal Invasive Lobular Carcinoma cell line model

Breast cancer is categorized by the molecular and histologic presentation of the tumor, with the major histologic subtypes being No Special Type (NST) and Invasive Lobular Carcinoma (ILC). ILC are characterized by growth in a single file discohesive manner with stromal infiltration attributed to their hallmark pathognomonic loss of E-cadherin (CDH1). Few ILC cell line models are available to researchers. Here we report the successful establishment and characterization of a novel ILC cell line, WCRC-25, from a metastatic pleural effusion from a postmenopausal Caucasian woman with metastatic ILC. WCRC-25 is an ER-negative luminal epithelial ILC cell line with both luminal and Her2-like features. It exhibits anchorage independent growth and haptotactic migration towards Collagen I. Sequencing revealed a CDH1 Q706* truncating mutation, together with mutations in FOXA1, CTCF, BRCA2 and TP53, which were also seen in a series of metastatic lesions from the patient. Copy number analyses revealed amplification and deletion of genes frequently altered in ILC while optical genome mapping revealed novel structural rearrangements. RNA-seq analysis comparing the primary tumor, metastases and the cell line revealed signatures for cell cycle progression and receptor tyrosine kinase signaling. To assess targetability, we treated WCRC-25 with AZD5363 and Alpelisib confirming WCRC-25 as susceptible to PI3K/AKT signaling inhibition as predicted by our RNA sequencing analysis. In conclusion, we report WCRC-25 as a novel ILC cell line with promise as a valuable research tool to advance our understanding of ILC and its therapeutic vulnerabilities. Financial supportThe work was in part supported by a Susan G Komen Leadership Grant to SO (SAC160073) and NCI R01 CA252378 (SO/AVL). AVL and SO are Komen Scholars, Hillman Foundation Fellows and supported by BCRF. This project used the UPMC Hillman Cancer Center and Tissue and Research Pathology/Pitt Biospecimen Core shared resource which is supported in part by award P30CA047904. This research was also supported in part by the University of Pittsburgh Center for Research Computing, RRID:SCR_022735, through the resources provided. Specifically, this work used the HTC cluster, which is supported by NIH award number S10OD028483. Finally, partial support was provided by the Magee-Womens Research Institute and Foundation, The Shear Family Foundation, and The Metastatic Breast Cancer Network.

cancer biology↗

nELISA: A high-throughput, high-plex platform enables quantitative profiling of the secretome

We present the nELISA, a high-throughput, high-fidelity, and high-plex protein profiling platform. DNA oligonucleotides are used to pre-assemble antibody pairs on spectrally encoded microparticles and perform displacement-mediated detection. Spatial separation between non-cognate antibodies prevents the rise of reagent-driven cross-reactivity, while read-out is performed cost-efficiently and at high-throughput using flow cytometry. nELISA can measure both protein concentration and their post-translational modifications. We assembled an inflammatory panel of 191 targets that were multiplexed without cross-reactivity nor impact on performance vs 1-plex signals, with sensitivities as low as 0.1 pg/mL and measurements spanning 7 orders of magnitude. We then performed a large-scale inflammatory-secretome perturbation screen of peripheral blood mononuclear cells (PBMCs), with cytokines as both perturbagens and read-outs, measuring 7,392 samples and generating [~]1.4M protein data points in under a week; a significant advance in throughput compared to other highly multiplexed immunoassays. We uncovered 447 significant cytokine responses, including multiple putatively novel ones, that were conserved across donors and stimulation conditions. We validate nELISA for phenotypic screening, where its capacity to faithfully report hundreds of proteins make it a powerful tool across multiple stages of drug discovery.

bioengineering↗

Rapid Restoration of Cell Phenotype and Matrix Forming Capacity Following Transient Nuclear Softening

The dense extracellular matrix of connective tissues impedes cell migration and subsequent matrix formation at sites of injury. We recently employed transient nuclear softening via histone deacetylase inhibition with trichostatin A (TSA) treatment to overcome the stiff nuclear impediments to cell migration through dense tissues and electrospun matrices. Despite these positive findings, the long-term implications of transient nuclear softening on cell transcriptional phenotype and matrix formation capacity are unknown. To address this, we investigated the influence of transient TSA treatment on porcine meniscal cell behavior, beginning with the efficacy and reproducibility of transient TSA treatment on histone acetylation and chromatin remodeling in vitro and cell migration through native meniscus tissue. Within 3 days after cessation of transient TSA treatment, histone acetylation and chromatin remodeling returned to control levels. Following TSA treatment, endogenous cell migration through native meniscus tissue increased greater than 3-fold compared to controls. Importantly, meniscal cells completely restored their transcriptional phenotype and maintained their capacity to respond transcriptionally and functionally to a secondary pro-matrix stimuli (i.e., transforming growth factor {beta}3) within 7 days after cessation of TSA treatment. Towards translation, we also showed the feasibility of biomaterial-delivered TSA to increase endogenous cell migration to a wound edge ex vivo. Together, this work defines the efficacy, reproducibility, safety, and feasibility of future translational approaches for nuclear softening to treat dense connective tissue injuries.

genomics↗