Search

A major challenge in the treatment of chronic inflammatory diseases including periodontal diseases is the development of therapeutics to safely and specifically direct resolution of inflammation in a localized manner. Here we demonstrate the efficacy of a novel approach that addresses this unmet clinical need. Using an enzyme fusion protein of indoleamine 2,3-dioxygenase 1 (IDO) and galectin-3 (Gal3) with tissue-anchored and thus localized immunomodulatory properties, we prevented and halted progression of induced polymicrobial periodontal disease. Efficacy was achieved with repeated treatment with IDO-Gal3 and was measured by effects on mandibular bone loss, soft tissue inflammation and local T cell plasticity. Specifically, both prophylactic and therapeutic administration of IDO-Gal3 were effective in reducing vertical mandibular bone loss and loss of mandibular bone volume and bone thickness induced by chronic polymicrobial infection. The efficacy observed is at least in part due to localized regulation of innate immune mediators such as IL-1β, IL-6 and IL-8 as well as chemoattractants including IP-10, MCP-1 and MIP-1α, while enhancing the expression of immunoregulatory cytokines such as IL-10. In addition, IDO-Gal3 treatment suppressed the induction of pathogenic CD4+Th1, CD8+Tc1, CD4+Th1/Th17, and CD8+Tc1/Tc17, while promoting the induction of homeostatic CD4+Th17, CD8+Tc17 and CD4+Tregs. Importantly, the efficacy of prophylactically and therapeutically administered IDO-Gal-3 is not dependent on bacterial burden as there were no appreciable effects on bacterial burden following either method of administration. Lastly, therapeutic rather than prophylactic administration of IDO-Gal3 is most effective in preventing mandibular bone loss through more robust innate and adaptive immune modulation. Together these and our previously published data indicate that therapeutic administration of IDO-Gal3 addresses the clinical needs for adjunctive therapeutics to treat active and/or established periodontal diseases.

ObjectiveControlling joint inflammation can improve osteoarthritis (OA) symptoms; however, current treatments often fail to provide long-term effects. We have developed an indoleamine 2,3-dioxygenase and galectin-3 fusion protein (IDO-Gal3). IDO converts tryptophan to kynurenines, directing the local environment toward an anti-inflammatory state; Gal3 binds carbohydrates and extends IDO’s joint residence time. In this study, we evaluated IDO-Gal3’s ability to alter OA-associated inflammation and pain-related behaviors in a rat model of established knee OA.MethodsJoint residence was first evaluated with an analog Gal3 fusion protein (NanoLuc™ and Gal3, NL-Gal3) that produces luminescence from furimazine. OA was induced in male Lewis rats via a medial collateral ligament and medial meniscus transection (MCLT+MMT). At 8 weeks, NL or NL-Gal3 were injected intra-articularly (n=8 per group), and bioluminescence was tracked for 4 weeks. Next, IDO-Gal3’s ability to modulate OA pain and inflammation was assessed. Again, OA was induced via MCLT+MMT in male Lewis rats, with IDO-Gal3 or saline injected into OA-affected knees at 8 weeks post-surgery (n=7 per group). Gait and tactile sensitivity were then assessed weekly. At 12 weeks, intra-articular levels of IL6, CCL2, and CTXII were assessed.ResultsThe Gal3 fusion increased joint residence in OA and contralateral knees (pConclusionIntra-articular IDO-Gal3 delivery provided long-term modulation of joint inflammation and pain-related behaviors in rats with established OA.

Summary paragraphChronic inflammation underlies the onset, progression and associated pain of numerous diseases.(1) Current anti-inflammatory treatments administered systemically are associated with moderate-to-severe side effects, while locally administered drugs have short-lived efficacy, and neither approach successfully modifies the underlying causality of disease.(2) We report a new way to locally modulate inflammation by fusing the enzyme indoleamine 2,3-dioxygenase 1 (IDO) to galectin-3 (Gal3). A general regulator of inflammation(3), IDO is immunosuppressive(4), catabolizing the essential amino acid tryptophan into kynurenine.(5) Recently we demonstrated that extracellular exogenous IDO regulates innate immune cell function(6), and envisioned delivering IDO into specific tissues would provide control of inflammation. However, proteins problematically diffuse away from local injection sites. Addressing this, we recently established that fusion to Gal3 anchors enzymes to tissues(7) via binding to extracellular glycans. Fusion protein IDO-Gal3 was retained in injected tissues and joints for up to a week or more, where it suppressed local inflammation in rodent models of endotoxin-induced inflammation, psoriasis, periodontal disease and osteoarthritis. Amelioration of local inflammation, disease progression and inflammatory pain were concomitant with homeostatic preservation of tissues without global immune suppression. Thus, IDO-Gal3 presents a new concept of anchoring immunomodulatory enzymes for robust control of focal inflammation in multiple disease settings.

OBJECTIVES/GOALS: Develop a strategy to restrict GDNF diffusion at an injected CNS tissue site for dopamine neuron rescue by endowing it with binding affinity for carbohydrates that are abundant on the cell surface and extracellular matrix. METHODS/STUDY POPULATION: GDNF will be fused to galectin-3 (G3), a human protein that binds to β-galactoside residues of cell surface and matrix glycoproteins. We characterized the binding of G3 fusion proteins to various glycoproteins and primary human myeloid cells. We incubated G3 fusions with CNS tissue ex vivo to measure their binding and depth of penetration via diffusion. We next plan to administer GDNF-G3 via CNS intracranial infusion in a murine PD model and then conduct behavioral PD phenotype testing via rotarod and pole descent to compare to non-parkinsonian controls. We will further examine the effects of GDNF-G3 on degeneration using immunohistochemical examination of post-mortem brain tissue. RESULTS/ANTICIPATED RESULTS: Based on results from previous clinical trials of GDNF delivery, we anticipate that a successful intervention using GDNF-G3 will result in rescue of midbrain dopaminergic neurons in a murine PD model. In murine CNS tissue, we observed binding to glycans at the tissue surfaces when incubated with G3 fusion proteins ex vivo, suggesting GDNF-G3 will remain localized to the injection site. Next we will administer GDNF-G3 via CNS intracranial infusion in a murine PD model and assess efficacy by behavior and histopathology. GDNF-G3-mediated dopamine neuron rescue are expected to slow or reverse the progression of PD in these animal models. DISCUSSION/SIGNIFICANCE OF IMPACT: PD treatments focus on symptomatic relief. Standard therapies have not been efficacious in rescuing of dopaminergic neurons. GDNF-G3 administered at the site of neurodegeneration would represent a milestone on the path to treating PD pathology and address limitations of GDNF delivery.