Biology subjects

Maisel, K.

Publications and source records attributed to Maisel, K..

13 recordsLinked to original sources

bioRxiv2026

Extracellular matrix proteins modulate lymphatic endothelial cell junction morphology and barrier function.

The extracellular matrix (ECM) plays a pivotal role in lymphatic vasculature physiology, yet the specific contribution of individual ECM components to lymphatic endothelial permeability remains poorly understood, limiting the development of physiologically relevant in vitro models for lymphatic disease research and therapeutic development. Here, we used an in vitro transwell platform to systematically investigate how four clinically relevant ECM proteins, collagen I, fibronectin, fibrin, and laminin, regulate human lymphatic endothelial cell (LEC) barrier function and junctional integrity. Fibrin and collagen I substrates enhanced barrier integrity, demonstrating 80% and 67% increases in transendothelial electrical resistance (TEER), respectively, compared to uncoated controls. FITC-dextran transport assays confirmed these findings, with fibrin and collagen I reducing permeability by 20% and 10%, respectively. Immunofluorescence analysis revealed elevated ZO-1 expression on fibrin, fibronectin, and laminin matrices, while VE-cadherin levels remained unchanged across conditions. Quantitative junctional analysis demonstrated that fibrin increased ZO-1 junction continuity by [~]35%, while collagen I and fibronectin enhanced continuity by [~]22%, with all ECM coatings reducing discontinuous junctions by 60-80%. Mechanistically, RhoA expression was reduced in LECs cultured on fibrin, suggesting decreased stress fiber formation contributes to enhanced barrier function, though overall actin cytoskeletal anisotropy remained unchanged. These findings demonstrate that ECM composition modulates LEC junctional organization and barrier integrity, with fibrin and collagen I exerting the most pronounced barrier-enhancing effects. This engineered platform provides a foundation for developing next-generation in vitro models of lymphatic vasculature that more accurately recapitulate physiological conditions, with applications in lymphedema research, cancer metastasis studies, and immune cell trafficking investigations.

bioengineering↗

bioRxiv2025

Development of a Novel Methyl Cellulose Hydrogel with Physiologically-Relevant Controlled Ethanol Release for Cervical Dysplasia Ablation

Cervical cancer is a leading cause of death in women in low- and middle-income countries (LMICs) and disproportionately affects women of minority populations in the US, primarily due to a lack of infrastructural support for specialized care. A promising treatment which meets accessibility requirements is ethyl cellulose (EC)-ethanol ablation--inducing necrotic cell death through application of ethanol to kill precancerous cells. While previous work focused on injecting EC-ethanol to ablate high-grade dysplasia (which can reach depths up to 5 mm below the tissue surface), low-grade dysplasia requires a different delivery method as it is much more superficial (reaching depths of only 1-3 mm). Here, we have developed a topical gel for local ethanol ablation of low-grade dysplasia with minimal damage to healthy cervical tissue. We investigated several gellants, including methyl cellulose (MC), EC, and Pluronic(R) F-127, to develop an ethanol gel that meets parameters for low cost and topical ease of use. Formulations with F-127 did not form gels with ethanol. Formulations with EC and MC were gel-forming. The MC-based formulations formed more uniform and stable gels that hold their own weight while still being spreadable at both room and body temperatures, key criterion for local cervical application. The optimal formulation contained 70% ethanol, 20% water, and 10% MC. One gram of this formulation represents approximately 5{cents} material cost, and formulated gels were stable for one week at least when stored at 4, 22, 30, and 37 {degrees}C. Additionally, the MC gel achieved localized ablation within 5 minutes after application to cervical cancer cells in-vitro. Taken together, we have developed a low-cost, efficacious, MC-based ethanol gel fit for translational testing to treat low-grade cervical dysplasia. This gel may provide a novel treatment option for women in LMICs, without causing major side effects or loss of healthy cervical tissue. Translational Impact StatementWe have developed a low-cost, efficacious, methyl cellulose-based ethanol gel fit for translational testing to topically treat low-grade cervical dysplasia. This addresses the need for a novel and accessible treatment option for women in low- and middle-income countries, which will not cause major side effects or loss of healthy cervical tissue. Ethics StatementAll work herein are the authors own original work. Authors have no conflicts of interest to disclose. Primary funding for the project was startup funds provided by the University of Maryland. All data available upon request.

bioengineering↗

bioRxiv2025

Synthetic Mucus Biomaterials Enable Localized Therapeutic Antibody Delivery in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic condition characterized by recurrent gastrointestinal inflammation that requires long-term therapeutic intervention. While anti-TNF- monoclonal antibodies (mAbs) are effective in maintaining remission in IBD, systemic delivery is associated with immunosuppression, poor targeting efficiency, and high cost. To address these limitations, we developed a synthetic mucin-based hydrogel for localized delivery of TNF--targeting mAbs. Mucins are heavily glycosylated biopolymers that naturally bind antimicrobial and anti-inflammatory proteins, making them well-suited for local biologic drug delivery at mucosal sites. Synthetic mucin-based hydrogels were formed by crosslinking mucin harvested from porcine small intestine with a 4-arm PEG-thiol and loaded with mAbs to evaluate biocompatibility, antibody release kinetics, and therapeutic efficacy. In vitro studies confirmed cytocompatibility of mucin-based hydrogels and demonstrated sustained release of full-length IgG antibodies, with enhanced release under proteolytic conditions simulating the gastrointestinal environment. Moreover, mucin-based hydrogels alone were found to modulate macrophage activation and dampen inflammation in LPS-stimulated macrophages. Treatment of LPS-stimulated macrophages with mAb-loaded hydrogels reduced pro-inflammatory cytokine production and macrophage activation, confirming retention of mAb bioactivity. Compared to antibodies administered in solution, in vivo biodistribution studies revealed greater absorption of antibodies when loaded in mucin-based hydrogels and administered via enema in TNBS-induced colitis mice likely due to enhanced adhesion to mucosal epithelium and slowed intestinal clearance. This study demonstrates the potential of mucin-based hydrogels as a platform for local mAb delivery in IBD, enabling targeted immunosuppression while minimizing systemic exposure.

bioengineering↗

bioRxiv2025

Fibroblasts regulate lymphatic barrier functions in a tissue dependent manner

Lymphatic dysfunction has been linked to several pathological conditions, including edema, inflammation, and cancer metastasis. The tight and adherens junction proteins between lymphatic endothelial cells (LECs) are important for preserving lymphatic vascular integrity. Despite the known role of fibroblasts in lymphangiogenesis, the direct impact of fibroblasts on LEC barrier function remains poorly understood. Here, normal human dermal fibroblast (NHDF) secretomes and non-contact co-culture models were used to examine how fibroblasts regulate human lymphatic endothelial cells (hLECs). Co-culture with dermal fibroblasts increased transendothelial electrical resistance (TEER) by > 110% and increased ZO-1 expression by >2-fold. VE-cadherin expression increased by at least 1.3-fold compared to controls. Furthermore, 4kDa dextran transport was markedly reduced, confirming an overall reduced hLEC permeability. Junction morphology analysis further showed a marked shift from discontinuous punctate and perpendicular junctions toward continuous ZO-1-rich borders, while actin anisotropy was reduced with redistribution away from aligned central stress fibers toward a more junction-supportive cytoskeletal architecture. Thrombin challenge revealed that fibroblasts also shape endothelial responses to inflammatory stress, indicating that stromal-endothelial crosstalk regulates both basal and stress-induced barrier behavior. Transcriptomic analysis identified two fibroblast-driven endothelial programs that converged on junctional remodeling but diverged in broader physiological features: activated NHDFs promoted lymphatic identity, junction stabilization, and a more quiescent endothelial state, whereas inactivated NHDFs favored extracellular matrix remodeling and partial EndoMT-like signaling while retaining some junction-supportive features. In contrast, lung fibroblast secretomes weakened barrier function, supporting the idea that stromal regulation of lymphatic permeability is tissue specific. Together, these findings identify fibroblasts as active regulators of lymphatic barrier physiology and reveal stromal heterogeneity as an important determinant of endothelial junction organization, transport, and tissue-specific lymphatic function. NEW AND NOTEWORTHYThis exciting work demonstrates that fibroblasts are active regulators of lymphatic endothelial barrier physiology during homeostasis. Dermal fibroblasts strengthen barrier function and reduce paracellular transport by promoting continuous junction organization, cytoskeletal remodeling, and extracellular matrix reprograming, while fibroblast state and tissue origin produce distinct endothelial programs.

bioengineering↗

bioRxiv2025

Inflammation modulates lymph node biomechanics in a sex-dependent manner

Lymph nodes are highly specialized immune organs that orchestrate the adaptive immune response. In the lymph nodes, naive B and T lymphocytes encounter cognate antigens, sparking their activation and response to foreign substances. Lymph nodes grow in response to an immune challenge, at least in part to accommodate increased numbers of infiltrating and proliferating B and T lymphocytes. This behavior is supported by a robust three-dimensional network of extracellular matrix (ECM) fibers and fibroblastic reticular cells (FRCs). ECM fibers and FRCs work synergistically to alternate stretching and contractile forces between them allowing the lymph node to maintain structural integrity during rapid tissue reconstruction. These changes ultimately alter the material properties of the lymph node, which can impact cell migration, proliferation, and differentiation. Recent work has investigated the physiological implications of the changing lymph node microenvironment; however, the biophysical properties of the lymph nodes during these changes remain largely unexplored. Here, we use multiple particle tracking microrheology (MPT), a minimally invasive nanoparticle-based technique to investigate the biophysical properties (elastic/loss moduli, microviscosity, pore size) of lymph nodes post inflammatory stimulus. Our results highlight mechanical changes both during the initial phases of the acute inflammatory response and upon resolution of inflammation, a topic that is relatively understudied. We show that B and T cell rich areas exhibit comparable changes in biomechanical properties over time, suggesting that they restructure in a similar fashion during acute inflammation. Additionally, for the first time, we show that biological sex modulates lymph node biomechanics in acute inflammation: Lymph nodes from female mice showed a [~]20-fold increase in elastic and loss moduli at peak inflammation, while lymph nodes from male mice had a [~]5-fold decrease in both moduli. Additionally, lymph nodes from female mice appeared to permanently remodel during the resolution of acute inflammation resulting in the maintenance of an overall higher elastic and loss modulus, while lymph nodes from male mice returned to the biomechanics of untreated lymph nodes. We also found that at least some of the changes in biomechanical properties were correlated with changes in ECM materials in the lymph nodes, suggesting a structure-function relationship. Overall, our studies provide key insights into how biomechanical properties in lymph nodes are altered during inflammation, a previously unstudied area, and lay the foundation for structure-function relationships involved in immune response. Additionally, we demonstrate a robust technique for the analysis of the lymph node interstitial tissue properties and how they vary with inflammatory stimuli.

bioengineering↗

bioRxiv2023

Mechanical Dissociation of Tissues for Single Cell Analysis Using a Simple Motorized Device

ABSTRACT/SUMMARYThe use of single cell analysis methods has grown rapidly in the last two decades and has led to rapid discoveries in cell biology and beyond. Single cell analysis requires complex systems like tissues to be dissociated, separating individual cells from extracellular tissue materials. This requires manual processing of tissues and materials through chopping, pipetting, and suspension with enzymes for degradation of the structural elements of the tissue. Manual processing can be time consuming and lead to variability between scientists. Automating this process through motorized dissociation could thus improve reproducibility of research and reduce time of cell manipulation prior to analysis. Here, we have designed a low-cost, customizable automatic tissue dissociator device that can be easily assembled by research groups for individual use. Our device allows for customizable programmed dissociation protocols for ease of use and reproducibility between researchers and can be placed into heat or cold environments based on the protocol need. We have found this device comparable in cell viability and reproducibility to manual dissociation, while significantly reducing time spent and even enhancing cells extracted from more fibrous tissues. Broad dissemination and use of this device could enhance single cell analysis reproducibility and provide a time-saving alternative to the currently used manual dissociation protocols.

cell biology↗

bioRxiv2023

Para- and transcellular transport kinetics of nanoparticles across lymphatic endothelial cells

Lymphatic vessels have received significant attention as drug delivery targets, as they shuttle materials from peripheral tissues to the lymph nodes, where adaptive immunity is formed. Delivery of immune modulatory materials to the lymph nodes via lymphatic vessels has been shown to enhance their efficacy and also improve bioavailability of drugs when delivered to intestinal lymphatic vessels. In this study we generated a three-compartment model of a lymphatic vessel with a set of kinematic differential equations to describe the transport of nanoparticles from surrounding tissues into lymphatic vessels. We used previously published data and collected additional experimental parameters, including transport efficiency of nanoparticles over time, and also examined how nanoparticle formulation affected the cellular transport mechanisms using small molecule inhibitors. This experimental data was incorporated into a system of kinematic differential equations and non-linear, least squares curve fitting algorithms were employed to extrapolate transport coefficients within our model. The subsequent computational framework produced some of the first parameters to describe transport kinetics across lymphatic endothelial cells and allows for the quantitative analysis of the driving mechanisms of transport into lymphatic vessels. Our model indicates that transcellular mechanisms, such as micro- and macropinocytosis, drive transport into lymphatics. This information is crucial to further design strategies that will modulate lymphatic transport for drug delivery, particularly in diseases like lymphedema, where normal lymphatic functions are impaired.

bioengineering↗

bioRxiv2023

Inhaled CpG increases survival and synergizes with checkpoint inhibition in lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a devastating disease primarily found in women of reproductive age that leads to cystic destruction of the lungs. Recent work has shown that LAM causes immunosuppression and that checkpoint inhibitors can be used as LAM treatment. Toll-like receptor (TLR) agonists can also re-activate immunity and the TLR9 agonist, CpG-ODN, has been effective in treating lung cancer in animal models. Here we investigate the use of TLR9 agonist CpG-ODN as LAM immunotherapy in combination with checkpoint inhibitor, anti-PD1, standard of care rapamycin and determine the immune mechanisms underlying therapeutic efficacy. We used survival studies, flow cytometry, ELISA, and histology to assess immune response and survival after intranasal treatment with CpG-ODN in combination with rapamycin or anti-PD1 therapy in a mouse model of metastatic LAM. We found that local administration of CpG-ODN enhances survival in a mouse model of LAM. We found that a lower dose led to longer survival likely due to fewer local side effects but increased LAM nodule count and size compared to the higher dose. CpG-ODN treatment also reduced regulatory T cells and increased the number of Th17 helper T cells as well as cytotoxic T cells. These effects appear to be mediated in part by plasmacytoid dendritic cells (pDCs), as depletion of pDCs reduces survival and abrogates Th17 T cell response. Finally, we found that CpG-ODN treatment is effective in early stage and progressive disease and is additive with anti-PD1 therapy and rapamycin. In summary, we have found that TLR9 agonist CpG-ODN can be used as LAM immunotherapy and effectively synergizes with rapamycin and anti-PD1 therapy in LAM.

immunology↗

bioRxiv2022

Multiple particle tracking using PEGylated nanoparticles reveals lymph node is riddled with heterogeneous pores smaller than reported and interstitial tissue material properties vary by lymph node location

Lymph nodes (LNs) are highly structured lymphoid organs that compartmentalize B and T cells in the outer cortex and inner paracortex, respectively, and are supported by a collagen-rich reticular network. Tissue material properties like viscoelasticity and diffusion of materials within extracellular spaces and their implications on cellular behavior and therapeutic delivery have been a recent topic of investigation. Here, we developed a nanoparticle system to investigate the rheological properties, including pore size and viscoelasticity, through multiple particle tracking (MPT) combined with LN slice cultures. Dense coatings with polyethylene glycol (PEG) allow nanoparticles to diffuse within the LN extracellular spaces. Despite differences in function in B and T cell zones, we found that extracellular tissue properties and mesh spacing do not change significantly in the cortex and paracortex, though nanoparticle diffusion was slightly reduced in B cell zones. Interestingly, our data suggest that LN pore sizes are smaller than the previously predicted 10 - 20 m, with pore sizes ranging from 500 nm - 1.5 m. Our studies also confirm that LNs exhibit viscoelastic properties, with an initial solid-like response followed by stress-relaxation at higher frequencies. Finally, we found that nanoparticle diffusion is dependent on LN location, with nanoparticles in skin draining LNs exhibiting a higher diffusion coefficient and pore size compared to mesenteric LNs. Our data shed new light onto LN interstitial tissue properties, pore size, and define surface chemistry parameters required for nanoparticles to diffuse within LN interstitium. Our studies also provide both a tool for studying LN interstitium and developing design criteria for nanoparticles targeting LN interstitial spaces. AbbreviationsLNs, FBS, EDC, NHS, ECM, PEG

immunology↗

bioRxiv2022

Discussion-based DEI education to help create inclusive and open BME research lab environments

Diversity in teams has been shown to enhance creativity and innovation, particularly in teams where all members felt a sense of belonging. Creating an inclusive environment in a lab setting that provides a sense of belonging to all is challenging. This is particularly true in a field like Biomedical Engineering/Bioengineering where diversity is multifaceted and includes peoples diverse personal/cultural backgrounds and also diverse scientific backgrounds. In a research lab, there is additional diversity in training, as most labs contain trainees at different levels (undergrad, grad, postdoc, high school). To aid in creating a sense of belonging in a research lab, we have devised a novel initiative based upon open group discussions on diversity, equity, and inclusion topics. The initiative included a first presentation/discussion by the PI to set the stage for defining diversity, equity, and inclusion, and provided examples of existing DEI issues within our field, such as lack of racial diversity in awards like the NIH New Innovator Award and among conference speakers. After the initial presentation, trainee-led, bi-weekly-structured discussions were maintained. First, discussions focused broadly on any DEI related topic to enhance general knowledge on DEI issues and provide discussion comfort among the group. Second, there was a period to deepen knowledge of a specific topic (in our example, microaggressions), which was followed up with a period of discussions on potential solutions (such as how to react when observing a microaggression and what to do in response to realizing ones own microaggression). Students reported that our discussions were the only ones they have had in their training thus far, and felt that these discussions made them feel like they belonged in the lab, made the lab more inclusive, enhanced their awareness of how to create inclusive spaces, and taught them about a variety of DEI topics. Overall, our DEI discussions have fostered open conversations within our lab group about DEI-related issues and topics at the lab, department, university, and countrywide levels and has established a space where students feel safe to voice their opinions and ask questions. We hope to ultimately use these DEI discussions to create actionable steps for addressing topics, e.g., microaggressions, in different scenarios that can be applied by group members in their future careers.

scientific communication and education↗

bioRxiv2022

Generating an in vitro gut model with physiologically relevant biophysical mucus properties

IntroductionGastrointestinal (GI) in vitro models have received lasting attention as an effective tool to model drug and nutrient absorption, study GI diseases, and design new drug delivery vehicles. A complete model of the GI epithelium should at a minimum include the two key functional components of the GI tract: mucus and the underlying epithelium. Mucus plays a key role in protecting and lubricating the GI tract, poses a barrier to orally administered therapies and pathogens, and serves as the microenvironment for the GI microbiome. These functions are reliant on the biophysical material properties of the mucus produced, including viscosity and pore size. MethodsIn this study, we generated in vitro models containing Caco-2 enterocyte-like cells and HT29-MTX goblet-like cells and determined the effects of coculture and mucus layer on epithelial permeability and biophysical properties of mucus using multiple particle tracking (MPT). ResultsWe found that mucus height increased as the amount of HT29-MTX goblet-like cells increased. Additionally, we found that increasing the amount of HT29-MTX goblet-like cells within culture corresponded to an increase in mucus pore size and mucus microviscosity, measured using MPT. When compared to ex vivo mucus samples from mice and pigs, we found that a 90:10 ratio of Caco-2:HT29-MTX coculture displayed similar mucus pore size to porcine jejunum and that the mucus produced from 90:10 and 80:20 ratios of cells shared mechanical properties to porcine jejunum and ileum mucus. ConclusionsGI coculture models are valuable tools in simulating the mucus barrier and can be utilized for a variety of applications including the study of GI diseases, food absorption, or therapeutic development. BiographyDr. Maisel joined the University of Maryland in January 2019 having done interdisciplinary training in nanotechnology, mucosal immunology, lymphatic immunology, and immunoengineering. She completed her PhD in Biomedical Engineering at the Johns Hopkins University in 2014 after which she was an NIH postdoctoral fellow at the University of Chicago in Molecular Engineering and Immunology. The Maisel Lab uses in vitro modeling, nanotechnology, and immunoengineering approaches to study and develop treatments for diseases at mucosal surfaces. They are interested in designing nanoparticles to take advantage of and study the interface between biological barriers, particularly the lymphatics, interstitial tissue, and mucosal surfaces, and nanoparticles. Dr. Maisel has won a number of awards, including NSF GRFP and NIH F32 fellowships as a trainee, the American Lung Association Dalsemer Award, LAM Foundation Career Development Award, an NSF CAREER Award, and an NIH NIGMS Maximizing Investigator Research Award. Her work has led to numerous high-impact publications, particularly in the field of drug delivery and mucosal immunoengineering, and several patents.

bioengineering↗

bioRxiv2021

Lymphatic Thrombosis and Impaired Lymph Drainage in Cigarette Smoke-Associated Emphysema

The lymphatic vasculature is critical for lung function, but defects in lymphatic function in the pathogenesis of lung disease is understudied. In mice, lymphatic dysfunction alone is sufficient to cause lung injury that resembles human emphysema. Whether lymphatic function is disrupted in cigarette smoke (CS)-induced emphysema is unknown. In this study, we investigated lung lymphatic function in the pathogenesis of CS-induced emphysema. Analysis of human lung tissue revealed significant lung lymphatic thrombosis in patients with emphysema compared to control smokers that increased with disease severity. In vitro assays demonstrated a direct effect of CS on lymphatic endothelial cell integrity. In a mouse model, CS exposure led to lung lymphatic thrombosis, decreased lymphatic drainage, and impaired leukocyte trafficking that preceded emphysema. Proteomic analysis of lymph confirmed upregulation of coagulation and inflammatory pathways in the lymphatics of CS-exposed mice compared to control mice. These data suggest that CS exposure results in lung lymphatic dysfunction with thrombosis, impaired leukocyte trafficking, and changes in the composition of lymph. In patients with emphysema, lung lymphatic thrombosis is seen with increasing disease severity. These studies for the first time demonstrate lung lymphatic dysfunction after cigarette smoke exposure and suggest a novel component in the pathogenesis of emphysema.

pathology↗

bioRxiv2020

Dense poly(ethylene glycol) coatings maximize nanoparticle transport across lymphatic endothelial cells

Lymphatic vessels have recently been shown to effectively deliver immune modulatory therapies to the lymph nodes, which enhances their therapeutic efficacy. Prior work has shown that lymphatics transport 10-250 nm nanoparticles from peripheral tissues to the lymph node. However, the surface chemistry required to maximize this transport is poorly understood. Here, we determined the effect of surface poly(ethylene glycol) (PEG) density and size on nanoparticle transport across lymphatic endothelial cells (LECs) by differentially PEGylated model polystyrene nanoparticles. Using an established in-vitro lymphatic transport model, we found PEGylation improved the transport of 100 and 40 nm nanoparticles across LECs 50-fold compared to the unmodified nanoparticles and that transport is maximized when the PEG is in a dense brush conformation or high grafting density (Rf/D = 4.9). We also determined that these trends are not size-dependent. PEGylating 40 nm nanoparticles improved transport efficiency across LECs 68-fold compared to unmodified nanoparticles. We also found that PEGylated 100 nm and 40 nm nanoparticles accumulate in lymph nodes within 4 hours after intradermal injection, while unmodified nanoparticles accumulated minimally. Dense PEGylation also led nanoparticles to travel the furthest distance from the injection site. Finally, we determined that nanoparticles are transported via both paracellular and transcellular mechanisms, and that PEG conformation modulates the cellular transport mechanisms. Our results suggest that PEG conformation is crucial to maximize nanoparticle transport across LECs and into lymphatic vessels, making PEG density a crucial design. Optimizing PEG density on nanoparticle formulations has the potential to enhance immunotherapeutic and vaccine outcomes.

bioengineering↗