Department of Periodontics: Theses and Dissertationshttp://hdl.handle.net/10675.2/6216702024-03-29T06:16:39Z2024-03-29T06:16:39ZDendritic Cell Derived Exosomes Loaded with Immunoregulatory Cargo Reprogram local Immune Responses and Inhibit Degenerative Bone Disease In vivoElashiry, Mahmoudhttp://hdl.handle.net/10675.2/6236722021-04-23T12:17:14Z2020-12-01T00:00:00ZDendritic Cell Derived Exosomes Loaded with Immunoregulatory Cargo Reprogram local Immune Responses and Inhibit Degenerative Bone Disease In vivo
Elashiry, Mahmoud
Background: Histopathological study of periodontitis (PD) lesions at sites of bone
loss reveals infiltration with dendritic cells (DC) CD4+ T cell clusters and other
inflammatory cells. DCs can direct bone protective T-regulatory cell (Tregs) responses,
or bone destructive T-helper 17 (Th17). The use of exosomes (EXO), natural
nanoparticles released by DCs and other cells, are under intense scrutiny in clinical trials
for autoimmune diseases and cancer, but no studies to date have harnessed DC-derived
EXO to regulate alveolar bone loss in PD.
Aim: To determine the ability of custom DC-derived EXO to reprogram immune
cell functions of recipient DCs and T cells and mitigate inflammatory bone loss in mice.
Methods: Murine bone marrow derived donor DC subtypes, including immune
regulatory DCs (regDC), immature DCs (iDC) and immune stimulatory (stimDC) DCs
were the source of purified DC EXO. Reg DC EXO were actively loaded with TGFB1/IL10
using ultrasonication. Preliminary in vitro studies of EXO cargo, stability and resistance
of cytokine cargo to proteolysis, as well as immune functions and osteoclastogenesis was
investigated. The following DC EXO subtypes were then tested in vivo in six groups of
mice, in the ligature induced PD model: Group 1, no ligature, Groups 2, 3, 4, 5 and 6,
8
ligature plus gingival injection of, respectively, PBS, regDC EXO, iDC EXO, stimDC EXO
and free TGFB1/IL10. Biodistribution and in vivo uptake of EXO by gingival recipient DCs
and T cells were tracked. The ability of DC EXO to modulate gingival recipient DC and
CD4 T cells and cytokine expression was confirmed. TRAP staining of histological
sections measured osteoclast number, while bone loss volume was measured in 3-D by
micro-CT.
Results: Injected EXO showed a high affinity for gingival site of inflammatory bone
loss. RegDC EXO containing TGFb/IL-10 cargo, protected cargo against proteolytic
degradation and were taken up by recipient DCs and T cells in vivo, promoting Tregs,
while inhibiting Th17 recruitment and inhibiting bone loss. In contrast, EXO subtypes
lacking TGFb/IL-10 or free TGFB/IL-10 did not shift the Treg-Th17 balance and did not
inhibit bone loss. Mechanistically, a key role for TGFb1 in induction of Tregs by regDC
EXO was found using blocking antibodies to TGFb and/or IL-10. T.E.M. analysis revealed
TGFb1 localized in the EXO lumen and in the transmembrane domain, which sustained
signaling in recipient DCs. Blocking experiments revealed that sustainable prolonged
TGFb1 signaling required initial interaction between regDCs EXO and TGFBR1 complex
on acceptor cells, followed by internalization of regDC EXO with TGFB1-TGFBR1
complex for sustained SMAD2/3 phosphorylation.
Conclusion: This is the first study to demonstrate the efficacy of DCs exosomes
for inhibition of experimental bone loss and the cellular immune mechanisms involved.
This provides the basis for a future novel immunotherapeutic strategy for PD in humans.
2020-12-01T00:00:00ZOrigins of Progenitor Cells Mediating Mineralized Tissue Regeneration in a Canine Supra-‐alveolar Critical Size Periodontal/Peri‐implant Defect ModelKoli, Komalhttp://hdl.handle.net/10675.2/3175092019-08-30T07:14:58Z2012-11-01T00:00:00ZOrigins of Progenitor Cells Mediating Mineralized Tissue Regeneration in a Canine Supra-‐alveolar Critical Size Periodontal/Peri‐implant Defect Model
Koli, Komal
2012-11-01T00:00:00ZMapping of Cellular and Molecular Early Events in Periodontal/Alveolar Wound Healing/Regeneration Using a Canine ModelConnolly, Sean P.http://hdl.handle.net/10675.2/3172442021-01-19T15:53:13Z2012-08-01T00:00:00ZMapping of Cellular and Molecular Early Events in Periodontal/Alveolar Wound Healing/Regeneration Using a Canine Model
Connolly, Sean P.
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2012-08-01T00:00:00Z