Microparticulate-based immunotherapy of Rheumatoid Arthritis

Thursday, October 24, 2024

4:00 PM - 4:15 PM EST

Location: Room 316

Invited Speaker(s)

JL

Jamal Lewis, PhD

Associate Professor
University of Florida
Gainesville, Florida, United States

Co-Author(s)

AT

Allen Tu, PhD

PostDoc
University of Florida
Davis, California, United States
RH

Rian Harriman

Graduate Research Assistant
University of California, Davis
Vacaville, California, United States

Introduction: Current paradigms for the treatment of autoimmune diseases (e.g. rheumatoid arthritis [RA]) are woefully inadequate, often missing the mark on desired physiological responses and not targeting the root cause of the disease. Predictably, novel approaches to re-establish immune homeostasis in patients afflicted by autoimmune conditions are now under intense investigation. Notably, we are developing an array of multifunctional, biomaterial-based ‘regulatory vaccines’ that can be easily administered to remediate some of the prevalent inflammatory diseases. In this talk, I will focus on two particulate systems currently under development in my lab, which attempt to control critical cellular and humoral mediators that engender conditions such as RA, and food allergy.

Materials and

Methods: Fabrication of REGvac: Briefly, REGvac was fabricated as previously described [4]. using double emulsion-solvent evaporation methods. Release kinetics were determined via ELISA or spectrophotometry at various timepoints. Scanning electron microscopy (SEM) images were taken using FEI Scios DualBeam FIB/SEM (Thermo Fisher). In vitro culture and treatment of bone marrow-derived dendritic cells: Dendritic cells were generated from bone marrow progenitors as previously described [4] then treated with either LPS, methotrexate (MTX), or REGvac for 72h, flow cytometry was performed and resolved on an Attune NxT flow cytometer (ThermoFisher). CIA/FIA induction in DBA/1J mice and REGvac treatment: Rheumatoid Arthritis was induced via immunization with type II collagen (Sigma) and citrullinated fibrinogen (Cayman Chemical) in Complete Freund’s Adjuvant (Sigma). Onset of severe RA initiated therapy with REGvac (2.5 mg s.c.) or methotrexate (2.5 mg/kg i.p.) in the abdominal region. Each paw was evaluated for a score of 0-3, (with 0 being no symptoms, and 3 being most severe erythema and swelling), and summed to give clinical score. Ankle thickness was measured using surgical calipers.

Results, Conclusions, and Discussions: Fabrication and characterization of REGvac.
REGvac fabrication yielded ~1µm and ~30µm MPs with spherical morphology for the small component (Fig. 1A) and large component (Fig. 1B) of REGvac via SEM images and exhibited a delayed release profile for the small MP component of REGvac and a burst release profile for the large MP component of REGvac (Fig. 1C).
REGvac induces a tolerogenic phenotype that resists LPS-induced stimulation in murine BMDCs. REGvac treatment of murine BMDCs suppressed CD80 expression, did not induce CD86 expression, and bestowed the ability to resist LPS-induced expression of CD80 and CD86. REGvac treatment ameliorates symptoms in CIA/FIA mice Upon onset of severe RA (clinical score > 6) REGvac, MTX, or PBS interventions were initiated for 8 weeks. REGvac treatment significantly reduced clinical score and ankle thickness (Fig. 3B) after 8 weeks.

In this study, we demonstrate that REGvac 2.0 is able to induce a stable tolerogenic phenotype in murine BMDCs that resists subsequent LPS-induced stimulation and ameliorate arthritic symptoms in the CIA/FIA mouse model of RA. These results give evidence that REGvac is able to exert therapeutic effects in vivo through modulation of DCs. Further validation that this microparticle therapy does not compromise the immune system would be a much-needed alternative to current therapies that immunocompromise the patient.

Acknowledgements (Optional):