M.Sc Thesis

M.Sc StudentIden Jennifer
SubjectThe Efficacy of Cannabis on Anklyosing Spondylitis
DepartmentDepartment of Biology
Supervisors DR. David Meiri
DR. Yishai Ofran
Full Thesis textFull thesis text - English Version


Ankylosing spondylitis (AS) is an auto-inflammatory disorder affecting the spinal and sacroiliac joints. Ankylosing refers to the eventual fusion of the vertebral bodies, while spondylitis delineates the profound and chronic inflammation of the spinal joints. Although the precise pathogenesis of this disease has not yet been elucidated, it is known that human leukocyte antigen (HLA)-B27?a major histocompatibility complex (MHC) class I molecule on dendritic cells (DC) and macrophages that presents antigenic peptides to T cells?is implicated in AS. A widely accepted theory for the pathogenesis of AS concerns the inherent structure of HLA-B27, which has a high proclivity to become misfolded, meaning that it oligomerizes and forms complexes in the lumen of the endoplasmic reticulum (ER), thus leading to ER stress which in turn activates the unfolded protein response (UPR) and induces an inappropriate immune response.

Consequentially, it is established that DCs and macrophages, wherein HLA-B27 mis-folding is resident, play a crucial role in eliciting an inflammatory response from CD4 subsets of T lymphocytes via secretion of pro-inflammatory cytokines, successively causing the T cells themselves to become activated, proliferative, and secrete pro-inflammatory cytokines as well. Additionally, the interleukin (IL)-23/IL-17 axis is critical in the inflammation of AS. Using this as a foundational target, the efficacy of a potential therapeutic was considered: namely, Cannabis.

The Cannabis plant contains a group of compounds called phytocannabinoids. Specifically, there is evidence that certain constituents, such as the non-psychotropic cannabidiol (CBD), are immunosuppressive. Therefore, we hypothesized that particular whole Cannabis extracts will ameliorate inflammatory cytokine secretion from dendritic cells and suppress the immune response from T cells thereafter. In this study, using AS as a model, in vitro cell line and in vitro human whole blood-derived cell paradigms for qualifying the immunosuppressive effect of various Cannabis extracts were developed to be applied to a spectrum of autoimmune and auto-inflammatory disorders.

Essentially, monocyte-derived dendritic cells (moDC) generated from either a human cell line or from the blood of healthy donors were altered to model a DC in AS and subjected to treatment with Cannabis extract. Cell-free DC supernatants were cultured together with T cells, and their viability and cytokine secretion were assessed. It was observed that a specific extract, Can3, was significantly effective in suppressing the secretion of inflammatory cytokines by DCs?namely, osteopontin (OPN) and IL-23?while also upregulating the secretion of an anti-inflammatory cytokine IL-10. Similarly, the viability of T cells after culture in the supernatant of extract-treated DCs was significantly reduced along with IL-17 secretion. These results were seen in both the co-culture systems of THP-1 moDCs with Jurkat T cells, and human moDCs with autologous CD4 T cells from healthy donors. Here, we show that Cannabis has intimations in altering the IL-23/IL-17 axis along with other inflammatory pathways, and has the potential as a therapeutic agent for targeting the chronic inflammation found in AS and other immune-mediated disorders.