Periodic Reporting for period 3 - PREVENT RA (Towards prevention of autoimmune diseases: the case of rheumatoid arthritis)
Período documentado: 2021-04-01 hasta 2022-02-28
Rheumatoid arthritis (RA) is a common and potentially invalidating autoimmune disease, causing pain and leading to joint destruction. Despite important achievements in the field, there is no cure for the disease. Our patients are treated too late and many of them have remaining symptoms that do not respond to current available therapies. We need therefore better therapies that will not only halt disease progression, but could prevent or cure of the disease.
Autoimmunity against posttranslational modified (mainly citrullinated) proteins is present in a large majority of the RA patients (defined as anti-citrullinated proteins antibody (ACPA) positive RA). We and others have proposed a new pathogenic model for RA where autoimmunity may initially be triggered by environmental agents (such as smoking and infections) inducing citrullination at mucosal sites (such as the lung and the gingival tissue). The resulting ACPA repertoire remains in the circulation for several years and through gradual changes can obtain a capacity to target similar posttranslational modifications (PTMs) in other parts of the body. We have previously shown that such PTMs are essential for the physiologic development of osteoclasts, we hypothesize that ACPAs will first target the bone and only later the joints, leading to the full-blown clinical picture of RA.
This model of a gradual development of ACPA-positive RA now allows studies of specific disease mechanisms in distinct phases of the disease, enabling early detection and opening possibilities for disease prevention. These studies have a large impact for each individual and for the society, through both generation of novel fundamental knowledge on specific pathogenic events antedating disease, as well as development and testing of new ways to interfere with these events. By attempting to change both the time (before any irreversible damage occurs) and the ways (by targeting specific early events) of RA intervention the current project is “beyond the current state of the art”.
The overall objectives are:
1. To gain a detailed understanding of the processes responsible for autoantibody generation outside the joints, specifically at the mucosal sites.
2. To develop new ways to identify disease-susceptible individuals and map targetable events responsible for this susceptibility.
3. To elucidate the mechanisms by which systemic autoimmunity targets the joints to first induce bone loss and pain and only in a second phase chronic joint inflammation.
Autoimmunity against posttranslational modified (mainly citrullinated) proteins is present in a large majority of the RA patients (defined as anti-citrullinated proteins antibody (ACPA) positive RA). We and others have proposed a new pathogenic model for RA where autoimmunity may initially be triggered by environmental agents (such as smoking and infections) inducing citrullination at mucosal sites (such as the lung and the gingival tissue). The resulting ACPA repertoire remains in the circulation for several years and through gradual changes can obtain a capacity to target similar posttranslational modifications (PTMs) in other parts of the body. We have previously shown that such PTMs are essential for the physiologic development of osteoclasts, we hypothesize that ACPAs will first target the bone and only later the joints, leading to the full-blown clinical picture of RA.
This model of a gradual development of ACPA-positive RA now allows studies of specific disease mechanisms in distinct phases of the disease, enabling early detection and opening possibilities for disease prevention. These studies have a large impact for each individual and for the society, through both generation of novel fundamental knowledge on specific pathogenic events antedating disease, as well as development and testing of new ways to interfere with these events. By attempting to change both the time (before any irreversible damage occurs) and the ways (by targeting specific early events) of RA intervention the current project is “beyond the current state of the art”.
The overall objectives are:
1. To gain a detailed understanding of the processes responsible for autoantibody generation outside the joints, specifically at the mucosal sites.
2. To develop new ways to identify disease-susceptible individuals and map targetable events responsible for this susceptibility.
3. To elucidate the mechanisms by which systemic autoimmunity targets the joints to first induce bone loss and pain and only in a second phase chronic joint inflammation.
Studies on triggering of autoimmunity at mucosal sites
We have recruited patients to characterize autoimmunity in the lungs, gingival tissue and bone marrow. Using this unique material, we analyzed cells and the antibody repertoire in the mucosal environment in both individuals at risk for and those having RA, showing that local inflammation associate with increased expression of citrullinated targets and antibody-producing cells. We have cloned a large array of monoclonal antibodies from cells obtained from different tissues and characterized these for antigen specificity, binding affinity, cross reactivity with bacterial and viral derived antigens and functional capacities. We were able to isolate monoclonal ACPAs from the lung, demonstrating mucosal production of ACPAs in very early stages of disease development and more importantly already before the onset of joint inflammation. Monoclonal ACPAs cloned from the lungs are able to modulate important cellular functions such as osteoclast activation many can bind to neutrophils. We have further characterized the presence and specificities of autoantibodies showing that specific patterns of ACPAs associate with presence of lung abnormalities in RA.
In summary, we provided new data linking immune activation, breach of tolerance and initiation of autoimmunity at mucosal sites in RA.
Studies on longitudinal development of autoimmunity
In this study, we focused on two cohorts: a retrospective cohort of serum samples donated by RA patients before disease onset (pre-RA cohort) and one prospective cohort of ACPA-positive individuals at risk for developing RA (RISK RA cohort). We show that ACPAs can be detected as early as 30 years before RA, with an increasing level towards disease onset. The asymptomatic autoimmunity phase proved to be sometimes longer than expected, which points to the importance of additional biomarkers for predicting disease development in a reasonable time perspective. To address this, we use the prospective RISK RA cohort where we generated an extensive characterization of the clinical status, patient reported outcomes, as well as large omics data (genome wide scanning, antibody profiling and proteomics biomarkers). From 400 recruited participants ca. 30% developed arthritis during a 2-year follow-up. The ones progressing to arthritis are more likely to present with tendon inflammation, certain ACPA reactivities, genetic risk factors and proteomics biomarkers. We are validating new patient-orientated tools to allow earlier diagnosis and better incorporation of patient outcomes. In summary, we implemented a new health program for individuals at risk for RA and identified new ways of risk estimation and communication.
Studies on joint targeting
Our working hypothesis is that ACPAs generated at mucosal sites can target joints through recognition of identical PTMs in the osteoclasts located in the bone and bone marrow. We have shown that ACPAs can induce activation of osteoclasts, synovial fibroblast migration and cause pain-like behavior and bone loss after injection in otherwise healthy mice. More recently we showed that passive transfer of ACPA in mice also induces subclinical tendon inflammation (resembling the clinical presentation of the at-risk individuals that eventually develop arthritis). The ACPAs effects are mediated by osteoclast, interleukin-8 and citrullination dependent pathways. Based on these finding we conduct a clinical study with osteoclasts inhibitor bisphosphonates, in ACPA-positive individuals at risk for developing RA. We have also established collaborations to test additional therapeutic strategies targeting IL-8 or citrullination.
Studies on perpetuation of chronic inflammation in established disease
We have characterized several early and late disease mechanisms in epidemiological and experimental studies and we have initiated novel projects to link these mechanisms and reconstruct experimentally the disease components that bridge the earliest symptoms with subsequent chronic joint inflammation.
We have recruited patients to characterize autoimmunity in the lungs, gingival tissue and bone marrow. Using this unique material, we analyzed cells and the antibody repertoire in the mucosal environment in both individuals at risk for and those having RA, showing that local inflammation associate with increased expression of citrullinated targets and antibody-producing cells. We have cloned a large array of monoclonal antibodies from cells obtained from different tissues and characterized these for antigen specificity, binding affinity, cross reactivity with bacterial and viral derived antigens and functional capacities. We were able to isolate monoclonal ACPAs from the lung, demonstrating mucosal production of ACPAs in very early stages of disease development and more importantly already before the onset of joint inflammation. Monoclonal ACPAs cloned from the lungs are able to modulate important cellular functions such as osteoclast activation many can bind to neutrophils. We have further characterized the presence and specificities of autoantibodies showing that specific patterns of ACPAs associate with presence of lung abnormalities in RA.
In summary, we provided new data linking immune activation, breach of tolerance and initiation of autoimmunity at mucosal sites in RA.
Studies on longitudinal development of autoimmunity
In this study, we focused on two cohorts: a retrospective cohort of serum samples donated by RA patients before disease onset (pre-RA cohort) and one prospective cohort of ACPA-positive individuals at risk for developing RA (RISK RA cohort). We show that ACPAs can be detected as early as 30 years before RA, with an increasing level towards disease onset. The asymptomatic autoimmunity phase proved to be sometimes longer than expected, which points to the importance of additional biomarkers for predicting disease development in a reasonable time perspective. To address this, we use the prospective RISK RA cohort where we generated an extensive characterization of the clinical status, patient reported outcomes, as well as large omics data (genome wide scanning, antibody profiling and proteomics biomarkers). From 400 recruited participants ca. 30% developed arthritis during a 2-year follow-up. The ones progressing to arthritis are more likely to present with tendon inflammation, certain ACPA reactivities, genetic risk factors and proteomics biomarkers. We are validating new patient-orientated tools to allow earlier diagnosis and better incorporation of patient outcomes. In summary, we implemented a new health program for individuals at risk for RA and identified new ways of risk estimation and communication.
Studies on joint targeting
Our working hypothesis is that ACPAs generated at mucosal sites can target joints through recognition of identical PTMs in the osteoclasts located in the bone and bone marrow. We have shown that ACPAs can induce activation of osteoclasts, synovial fibroblast migration and cause pain-like behavior and bone loss after injection in otherwise healthy mice. More recently we showed that passive transfer of ACPA in mice also induces subclinical tendon inflammation (resembling the clinical presentation of the at-risk individuals that eventually develop arthritis). The ACPAs effects are mediated by osteoclast, interleukin-8 and citrullination dependent pathways. Based on these finding we conduct a clinical study with osteoclasts inhibitor bisphosphonates, in ACPA-positive individuals at risk for developing RA. We have also established collaborations to test additional therapeutic strategies targeting IL-8 or citrullination.
Studies on perpetuation of chronic inflammation in established disease
We have characterized several early and late disease mechanisms in epidemiological and experimental studies and we have initiated novel projects to link these mechanisms and reconstruct experimentally the disease components that bridge the earliest symptoms with subsequent chronic joint inflammation.
By attempting to change both the time (before any irreversible damage occurs) and the ways (by targeting specific early events) of intervention in RA the current project is beyond the current state of the art. Progress have been achieved in
(1). Identification and characterization of novel pathogenic events responsible for disease initiation, (2). Development of a new health program for individuals at risk of developing disease, (3). Implementation of new ways to calculate and communicate the risk of developing disease, (4). Identification of new therapeutic targets and (5), Initiation of the first clinical proof of concept study.
(1). Identification and characterization of novel pathogenic events responsible for disease initiation, (2). Development of a new health program for individuals at risk of developing disease, (3). Implementation of new ways to calculate and communicate the risk of developing disease, (4). Identification of new therapeutic targets and (5), Initiation of the first clinical proof of concept study.