Biology subjects

Shea, L. D.

Publications and source records attributed to Shea, L. D..

9 recordsLinked to original sources

bioRxiv2026

Immune Biomarkers of Islet Transplant Rejection Revealed by Synthetic Immunological Niche

Islet transplantation can restore glycemic control in type 1 diabetes, yet the heterogeneity of patient immune responses and transplant outcomes motivates the need for technologies to monitor the graft. Since transplanted islets are not readily accessible for biopsy due to their diffuse engraftment within the liver, clinical monitoring relies on measurements such as islet mass, blood glucose, and C-peptide levels, which are lagging indicators that change only after substantial graft injury. Here, we developed a minimally invasive synthetic immunological niche (IN) that captures graft-associated immune responses through serial subcutaneous biopsy. We evaluated the IN across murine syngeneic, allogeneic, and autoimmune islet transplant models, including CD40/CD154 costimulatory blockade with anti-CD40L. In syngeneic versus allogeneic recipients, IN identified immune populations and transcriptomic signatures that mirrored the graft and distinguished healthy from rejecting grafts. In anti-CD40L treated allografts, IN revealed innate macrophage- and dendritic cell-associated programs linked to graft acceptance versus rejection, whereas IN from untreated allografts showed stronger adaptive immune signatures. Longitudinal IN profiling further detected progressive inflammatory activation in accepted allografts, indicating persistent subclinical risk. Finally, in an autoimmune allograft model treated with anti-CD40L plus rapamycin, IN identified a 13-gene signature that separated early from late rejection trajectories and distinguished autoimmune-from alloimmune-associated rejection programs. Overall, these findings establish IN as a surrogate tissue for minimally invasive monitoring of islet graft and early detection of rejection-associated immune dysregulation. One Sentence SummaryAn engineered immunological niche captures distinct immune signatures of allo- and auto-mediated islet transplant rejection

bioengineering↗

bioRxiv2026

Synthetic Immunological Niche Reveals Early Immune Dysregulationand Stratifies Therapeutic Response in Type 1 Diabetes

In Type 1 Diabetes (T1D), disease onset and response to immunotherapy vary widely among individuals, reflecting heterogeneous stage-specific immune dysregulation that remains undefined. To investigate this heterogeneity, we engineered a microporous polycaprolactone scaffold that forms a synthetic immunological niche (IN) upon subcutaneous implantation, enabling in vivo capture of systemic immune dysregulation. In non-obese diabetic (NOD) mice, longitudinal transcriptomic profiling of IN-infiltrating cells identified early-stage genes relatively enriched for myeloid cells, followed by progressive increases in T cell-associated dysregulation at later stages that distinguished T1D progressors from non-progressors. We derived an early-stage IN-based T1D gene signature capturing immune alterations. The signature stratified NOD progressors from non-progressors as early as 6 weeks of age and was conserved across human T1D datasets, distinguishing T1D from non-diabetic individuals in spleen and pancreatic lymph node samples, but not peripheral blood. Signature-based stratification further revealed enrichment of macrophage-associated TNF- pathways in NOD progressors, validated in human T1D islets. Given heterogeneous response to anti-TNF- therapy, IN profiling identified resistance-associated mechanisms and enabled derivation of a pathway score that prospectively distinguished treatment-sensitive from resistant mice prior to therapy, establishing the IN as a minimally invasive platform for detecting stage-wise immune dysregulation and stratifying immunotherapy response in T1D.

bioengineering↗

bioRxiv2026

Microtubule Stabilization and Biomaterial Guidance Synergize to Enhance CST Regeneration and Motor Recovery After Chronic SCI.

Spinal cord injury (SCI) results in loss of sensory and motor function below the level of damage, with chronic injuries presenting unique challenges for regenerative therapies. While multichannel biomaterial interventions have shown promise in promoting axonal regeneration, circuit restoration, and motor recovery in acute SCI, achieving similar outcomes in chronic injury models remains challenging due to a combination of intrinsic and extrinsic factors. These include the reduced capacity of the neuronal cell body to sustain a growth-activated state and the formation of a physical and chemical barrier at the injury site, preventing axonal growth. To address these challenges and promote motor recovery after chronic injury, we investigated the combinatorial effect of two regenerative approaches: 1) the implantation of poly (lactide-co-glycolide) (PLG) biomaterial bridge to guide axonal growth through the injury site, and 2) the delivery of Epothilone B (EpoB), a microtubule stabilizer that strengthens axons to promote regrowth. We used a transgenic mouse model that selectively expresses a red fluorescent protein variant (tdTomato) reporter throughout the corticospinal tract (CST) under control of the Crym promoter (Crym-tdTomato). We demonstrated that the combination of bridge implantation 60 days after surgical hemisection at C5 with EpoB improved locomotor function. At 12 weeks post-bridge implantation, immunohistology revealed axon regeneration in mice receiving implantation, but not EpoB or no-implant controls. The addition of EpoB significantly increased the volume of both total and CST axons regenerating through the biomaterial channels. Diffusion tensor magnetic resonance imaging (DTI) analysis identified enhanced fractional anisotropy (FA), axial diffusivity (AD), and mean diffusivity (MD) in the bridge region in the combination treatment group, consistent with new intact axons. Furthermore, EpoB enhanced the myelination of regenerated axons in the bridge. Finally, we investigated the proteomic profile of corticospinal neurons ipsilateral and contralateral to the SCI lesion and bridge, comparing the effect of EpoB treatment. Mass spectrometry-based analysis of laser-captured cells in this paradigm identified activation of a regeneration program by corticospinal neurons. These findings present a novel approach to enhance regenerative neural repair and locomotor recovery in chronic SCI.

neuroscience↗

bioRxiv2024

Limitations in mitochondrial programming restrain the differentiation and maturation of human stem cell-derived β cells

Pluripotent stem cell (SC)-derived islets offer hope as a renewable source for {beta} cell replacement for type 1 diabetes (T1D), yet functional and metabolic immaturity may limit their long-term therapeutic potential. Here, we show that limitations in mitochondrial transcriptional programming impede the formation of SC-derived {beta} (SC-{beta}) cells. Utilizing transcriptomic profiling, assessments of chromatin accessibility, mitochondrial phenotyping, and lipidomics analyses, we observed that SC-{beta} cells exhibit reduced oxidative and mitochondrial fatty acid metabolism compared to primary human islets that are related to limitations in key mitochondrial transcriptional networks. Surprisingly, we found that reductions in glucose-stimulated mitochondrial respiration in SC-islets were not associated with alterations in mitochondrial mass, structure, or genome integrity. In contrast, SC-islets show limited expression of targets of PPAR, which regulate mitochondrial programming, yet whose functions in {beta} cell differentiation are unknown. Importantly, treatment with WY14643, a potent PPAR agonist, induced expression of mitochondrial targets, improved insulin secretion, and increased the formation of SC-{beta} cells both in vitro and following transplantation. Thus, PPAR-dependent mitochondrial programming promotes the differentiation of SC-{beta} cells and may be a promising target to improve {beta} cell replacement efforts for T1D.

developmental biology↗

bioRxiv2021

Neutrophil and natural killer cell imbalances prevent muscle stem cell mediated regeneration following murine volumetric muscle loss

Volumetric muscle loss (VML) overwhelms the innate regenerative capacity of mammalian skeletal muscle (SkM), leading to numerous disabilities and reduced quality of life. Immune cells are critical responders to muscle injury and guide tissue resident stem cell and progenitor mediated myogenic repair. However, how immune cell infiltration and inter-cellular communication networks with muscle stem cells are altered following VML and drive pathological outcomes remains underexplored. Herein, we contrast the cellular and molecular mechanisms of VML injuries that result in fibrotic degeneration or regeneration of SkM. Following degenerative VML injuries, we observe heightened infiltration of natural killer (NK) cells as well as persistence of neutrophils beyond two weeks post injury. Functional validation of NK cells revealed an antagonistic role on neutrophil accumulation in part via inducing apoptosis and CCR1 mediated chemotaxis. The persistent infiltration of neutrophils in degenerative VML injuries was found to contribute to impairments in muscle stem cell regenerative function, which was also attenuated by transforming growth factor beta 1 (TGF{beta}1). Blocking TGF{beta} signaling reduced neutrophil accumulation and fibrosis, as well as improved muscle specific force. Collectively, these results enhance our understanding of immune cell-stem cell crosstalk that drives regenerative dysfunction and provide further insight into possible avenues for fibrotic therapy exploration. SINGLE SENTENCE SUMMARYComparison of muscle injuries resulting in regeneration or fibrosis reveals inter-cellular communication between neutrophils and natural killer cells impacts muscle stem cell mediated repair.

cell biology↗

bioRxiv2020

Lentiviral interleukin-10 gene therapy preserves fine motor circuitry and function after a cervical spinal cord injury in male and female mice

In mammals, spinal cord injuries often result in muscle paralysis through the apoptosis of lower motor neurons and denervation of neuromuscular junctions. Previous research shows that the inflammatory response to a spinal cord injury can cause additional tissue damage after the initial trauma. To modulate this inflammatory response, we delivered lentiviral anti-inflammatory interleukin-10, via loading onto an implantable biomaterial scaffold, into a left-sided hemisection at the C5 vertebra in mice. We hypothesized that improved behavioral outcomes associated with anti-inflammatory treatment are due to the sparing of fine motor circuit components. We examined behavioral recovery using a ladder beam, lower motor neuron apoptosis and muscle innervation using histology, and electromyogram recordings using intraspinal optogenetic stimulation at 2 weeks post-injury. Ladder beam analysis shows interleukin-10 treatment results in significant improvement of behavioral recovery at 2 and 12 weeks post-injury when compared to mice treated with a control virus. Histology shows interleukin-10 results in greater numbers of lower motor neurons and muscle innervation at 2 weeks post-injury. Furthermore, electromyogram recordings suggest that interleukin-10-treated animals have signal-to-noise ratios and peak-to-peak amplitudes more similar to that of uninjured controls than to that of control injured animals at 2 weeks post-injury. These data show that gene therapy using anti-inflammatory interleukin-10 can significantly reduce lower motor neuron loss, muscle denervation, and subsequent motor deficits after a spinal cord injury. Together, these results suggest that early modulation of the injury response can preserve muscle function with long-lasting benefits.

neuroscience↗

bioRxiv2019

Cargo-free scaffold implant recruits metastatic cancer cells via lung-mimicking myeloid cell S100A8/A9 axis

Pre-metastatic niches in distant tissue facilitate metastasis from the primary tumor. Cargo-free porous polymer scaffolds implanted in tumor-bearing mice act as synthetic metastatic niches recruiting metastasizing cancer cells. Herein, we investigated the mechanisms by which these implants attract cancer cells from circulation. Scaffolds attract cancer cells in part via S100A8/A9 secreted by Gr1+ myeloid cells in a mechanism that mimics lung metastasis. Further, cancer cells attracted to the scaffold have a lung-tropic gene expression signature regardless of their tissue of origin. The scaffold implant reduces metastasis to the lung suggesting otherwise lung-tropic cancer cells are diverted to the scaffold. The suppression of metastatic spread by the scaffold suggests this mechanism may be exploited for novel therapies, and may broadly influence the design of scaffold-based drug delivery system for anti-cancer therapy.

bioengineering↗

bioRxiv2019

Human lung organoids develop into adult airway-like structures directed by physico-chemical biomaterial properties

Tissues derived from human pluripotent stem cell (hPSC) often represent early developmental time points. Yet, when transplanted into immunocompromised mice, these hPSC-derived tissues further mature, which has been enhanced with biomaterial scaffolds, gaining tissue structure and cell types similar to the native adult lung. Our goal was to define the physico-chemical biomaterial properties, including the polymer type, degradation, and pore interconnectivity of the scaffolds. Transplantation of human lung organoids (HLOs) on microporous poly(lactide-co-glycolide) (PLG) scaffolds or polycaprolactone (PCL) produced organoids that formed tube-like structures that resembled both the structure and cellular diversity of an adult lung airway. Microporous scaffolds formed from poly(ethylene glycol) (PEG) hydrogel scaffolds inhibit maturation and the HLOs remain as lung progenitors. The structures formed from cells that occupy multiple pores within the scaffold, and pore interconnectivity and polymer degradation contributed to the maturation. Finally, the overall size of the generated airway structure and the total size of the tissue was influenced by the material degradation rate. Collectively, these biomaterial platforms provide a set of tools to promote maturation of the tissues and to control the size and structure of the organoids.

bioengineering↗

bioRxiv2019

Microporous scaffolds drive assembly and maturation of progenitors into β-cell clusters

Human pluripotent stem cells (hPSCs) represent a promising cell source for the development of {beta}-cells for use in therapies for type 1 diabetes. Current culture approaches provide the signals to drive differentiation towards {beta}-cells, with the cells spontaneously assembling into clusters. Herein, we adapted the current culture systems to cells seeded on microporous biomaterials, with the hypothesis that the pores can guide the assembly into {beta}-cell clusters of defined size that can enhance maturation. The microporous scaffold culture allows hPSC-derived pancreatic progenitors to form clusters at a consistent size as cells undergo differentiation to immature {beta}-cells. By modulating the scaffold pore sizes, we observed 250-425 {micro}m pore size scaffolds significantly enhance insulin expression and key {beta}-cell maturation markers compared to suspension cultures. Furthermore, when compared to suspension cultures, the scaffold culture showed increased insulin secretion in response to glucose stimulus indicating the development of functional {beta}-cells. In addition, scaffolds facilitated cell-cell interactions enabled by the scaffold design and cell-mediated matrix deposition of extracellular matrix (ECM) proteins associated with the basement membrane of islet cells. We further investigated the influence of ECM on cell development by incorporating an ECM matrix on the scaffold prior to cell seeding; however, their presence did not further enhance maturation. These results suggest the microporous scaffold culture facilitates 3D cluster formation, supports cell-cell interactions, and provides a matrix similar to a basement membrane to drive in vitro hPSC-derived {beta}-cell maturation and demonstrates the feasibility of these scaffolds as a biomanufacturing platform.

bioengineering↗