B.A., University of California, Berkeley, Molecular and Cell Biology (2012)
Doctor of Philosophy, Northwestern University (2017)
Monogenic diseases of the immune system, also known as inborn errors of immunity, are caused by single-gene mutations resulting in immune deficiency and dysregulation. More than 350 diseases have been described to date, and the number is rapidly expanding, with increasing availability of next-generation sequencing facilitating the diagnosis. The spectrum of immune dysregulation is wide, encompassing deficiencies in humoral, cellular, innate, and adaptive immunity; phagocytosis; and the complement system, which lead to autoinflammation and autoimmunity. Multiorgan autoimmunity is a dominant symptom when genetic mutations lead to defects in molecules essential for the development, survival, and/or function of regulatory T (Treg) cells. Studies of "Tregopathies" are providing critical mechanistic information on Treg cell biology, the role of Treg cell-associated molecules, and regulation of peripheral tolerance in human subjects. The pathogenic immune networks underlying these diseases need to be dissected to apply and develop immunomodulatory treatments and design curative treatments using cell and gene therapy. Here we review the pathogenetic mechanisms, clinical presentation, diagnosis, and current and future treatments of major known Tregopathies caused by mutations in FOXP3, CD25, cytotoxic Tlymphocyte-associated antigen 4 (CTLA4), LPS-responsive and beige-like anchor protein (LRBA), and BTB domain and CNC homolog 2 (BACH2) and gain-of-function mutations in signal transducer and activator oftranscription 3 (STAT3). We also discuss deficiencies in genesencoding STAT5b and IL-10 or IL-10 receptor aspotential Tregopathies.
View details for DOI 10.1016/j.jaci.2018.10.026
View details for PubMedID 30527062
Islet transplantation is a promising therapeutic option for type 1 diabetes mellitus, yet the current delivery into the hepatic portal vasculature is limited by poor engraftment. Biomaterials have been used as a means to promote engraftment and function at extrahepatic sites, with strategies being categorized as encapsulation or microporous scaffolds that can either isolate or integrate islets with the host tissue, respectively. Although these approaches are typically studied separately using distinct material platforms, herein, we developed nondegradable polyethylene glycol (PEG)-based hydrogels for islet encapsulation or as microporous scaffolds for islet seeding to compare the initial engraftment and function of islets in syngeneic diabetic mice. Normoglycemia was restored with transplantation of islets within either encapsulating or microporous hydrogels containing 700 islet equivalents (IEQ), with transplantation on microporous hydrogels producing lower blood glucose levels at earlier times. A glucose challenge test at 1 month after transplant indicated that encapsulated islets had a delay in glucose-stimulated insulin secretion, whereas microporous hydrogels restored normoglycemia in times consistent with native pancreata. Encapsulated islets remained isolated from the host tissue, whereas the microporous scaffolds allowed for revascularization of the islets after transplant. Finally, we compared the inflammatory response after transplantation for the two systems and noted that microporous hydrogels had a substantially increased presence of neutrophils. Collectively, these findings suggest that both encapsulation and microporous PEG scaffold designs allow for stable engraftment of syngeneic islets and the ability to restore normoglycemia, yet the architecture influences islet function and responsiveness after transplantation.
View details for DOI 10.1002/bit.26741
View details for Web of Science ID 000444072700020
View details for PubMedID 29873059
View details for PubMedCentralID PMC6131066
Current strategies for treating autoimmunity involve the administration of broad-acting immunosuppressive agents that impair healthy immunity. Intravenous (i.v.) administration of poly(lactide- co-glycolide) nanoparticles (NPs) containing disease-relevant antigens (Ag-NPs) have demonstrated antigen (Ag)-specific immune tolerance in models of autoimmunity. However, subcutaneous (s.c.) delivery of Ag-NPs has not been effective. This investigation tested the hypothesis that codelivery of the immunomodulatory cytokine, transforming growth factor beta 1 (TGF-?), on Ag-NPs would modulate the immune response to Ag-NPs and improve the efficiency of tolerance induction. TGF-? was coupled to the surface of Ag-NPs such that the loadings of Ag and TGF-? were independently tunable. The particles demonstrated bioactive delivery of Ag and TGF-? in vitro by reducing the inflammatory phenotype of bone marrow-derived dendritic cells and inducing regulatory T cells in a coculture system. Using an in vivo mouse model for multiple sclerosis, experimental autoimmune encephalomyelitis, TGF-? codelivery on Ag-NPs resulted in improved efficacy at lower doses by i.v. administration and significantly reduced disease severity by s.c. administration. This study demonstrates that the codelivery of immunomodulatory cytokines on Ag-NPs may enhance the efficacy of Ag-specific tolerance therapies by programming Ag presenting cells for more efficient tolerance induction.
View details for DOI 10.1021/acs.bioconjchem.7b00624
View details for Web of Science ID 000428356300025
View details for PubMedID 29148731
The development of novel immunomodulatory strategies that might decrease the need for systemic immune suppression would greatly enable the utility of cell-based therapies. Cell transplantation on biomaterial scaffolds offers a unique opportunity to engineer a site to locally polarize immunogenic antigen generation. Herein, we investigated the localized delivery of IL-33, which is a novel cytokine that has been shown to have beneficial immunomodulatory effects in certain transplant models as mediating anti-inflammatory properties in the adipose tissue, to determine its feasibility for use as an immunomodulatory agent.Localized IL-33 delivery from poly(lactide-co-glycolide) (PLG) scaffolds implanted into the epididymal fat specifically increased the Foxp3+ population of CD4+ T cells in both blank scaffold implants and scaffolds seeded with allogeneic islets. In allogeneic islet transplantation, we found IL-33 delivery results in a local upregulation of graft-protective T cells where 80% of the local CD4+ population is Foxp3+ and overall numbers of graft destructive CD8+ T cells are decreased, resulting in a prolonged graft survival. Interestingly, local IL-33 also delayed islet engraftment by primarily inducing a local upregulation of Th2 cytokines, including IL-4 and IL-5, leading to increased populations of ST2+ Type 2 innate lymphoid cells (ILC2s) and Siglec F+ eosinophils.These results suggest that local IL-33 delivery from biomaterial scaffolds can be used to increase Tregs enriched in adipose tissue and reduce graft-destructive T cell populations but may also promote innate cell populations that can delay cell engraftment.
View details for DOI 10.1016/j.regen.2018.01.003
View details for PubMedID 29869643
View details for PubMedCentralID PMC5983906
Depending on the stress, plasma membrane alterations activate or inhibit yeast target of rapamycin (TOR) complex 2, which, in turn, upregulates or downregulates the activity of its essential downstream effector, protein kinase Ypk1. Through phosphorylation of multiple substrates, Ypk1 controls many processes that restore homeostasis. One such substrate is protein kinase Fpk1, which is negatively regulated by Ypk1. Fpk1 phosphorylates and stimulates flippases that translocate aminoglycerophospholipids from the outer to the inner leaflet of the plasma membrane. Fpk1 has additional roles, but other substrates were uncharacterized. We show that Fpk1 phosphorylates and inhibits protein kinase Akl1, related to protein kinases Ark1 and Prk1, which modulate the dynamics of actin patch-mediated endocytosis. Akl1 has two Fpk1 phosphorylation sites (Ark1 and Prk1 have none) and is hypophosphorylated when Fpk1 is absent. Conversely, under conditions that inactivate TORC2-Ypk1 signaling, which alleviates Fpk1 inhibition, Akl1 is hyperphosphorylated. Monitoring phosphorylation of known Akl1 substrates (Sla1 and Ent2) confirmed that Akl1 is hyperactive when not phosphorylated by Fpk1. Fpk1-mediated negative regulation of Akl1 enhances endocytosis, because an Akl1 mutant immune to Fpk1 phosphorylation causes faster dissociation of Sla1 from actin patches, confers elevated resistance to doxorubicin (a toxic compound whose entry requires endocytosis), and impedes Lucifer yellow uptake (a marker of fluid phase endocytosis). Thus, TORC2-Ypk1, by regulating Fpk1-mediated phosphorylation of Akl1, adjusts the rate of endocytosis.
View details for DOI 10.1128/MCB.00627-16
View details for Web of Science ID 000397578200010
View details for PubMedID 28069741
View details for PubMedCentralID PMC5359421
Biomaterial scaffolds are central to many regenerative strategies as they create a space for infiltration of host tissue and provide a platform to deliver growth factors and progenitor cells. However, biomaterial implantation results in an unavoidable inflammatory response, which can impair tissue regeneration and promote loss or dysfunction of transplanted cells. We investigated localized TGF-?1 delivery to modulate this immunological environment around scaffolds and transplanted cells. TGF-?1 was delivered from layered scaffolds, with protein entrapped within an inner layer and outer layers designed for cell seeding and host tissue integration. Scaffolds were implanted into the epididymal fat pad, a site frequently used for cell transplantation. Expression of cytokines TNF-?, IL-12, and MCP-1 were decreased by at least 40% for scaffolds releasing TGF-?1 relative to control scaffolds. This decrease in inflammatory cytokine production corresponded to a 60% decrease in leukocyte infiltration. Transplantation of islets into diabetic mice on TGF-?1 scaffolds significantly improved the ability of syngeneic islets to control blood glucose levels within the first week of transplant and delayed rejection of allogeneic islets. Together, these studies emphasize the ability of localized TGF-?1 delivery to modulate the immune response to biomaterial implants and enhance cell function in cell-based therapies.
View details for DOI 10.1016/j.biomaterials.2015.11.065
View details for Web of Science ID 000370094900002
View details for PubMedID 26701143
View details for PubMedCentralID PMC4706476