Skip to main content

Targeting epigenetic REPROGRamming of innate immune cells in Atherosclerosis Management and other chronic inflammatory diseases

Periodic Reporting for period 3 - REPROGRAM (Targeting epigenetic REPROGRamming of innate immune cells in Atherosclerosis Management and other chronic inflammatory diseases)

Reporting period: 2019-01-01 to 2019-12-31

Up to 70% of cardiovascular events are not prevented by current therapeutic regimens. In search for additional, innovative strategies, immune cells have been recognized as key players contributing to atherosclerotic plaque progression and destabilization. Particularly the role of innate immune cells is of major interest, following the recent paradigm shift that innate immunity (TI), considered to be incapable of learning ability, does exhibit a memory feature transduced via epigenetic modulation. Compelling evidence shows that atherosclerotic factors promote immune cell migration by pre-activation of innate immune cells. In this project called REPROGRAM, we aim to prove that innate immune cell activation via epigenetic reprogramming perpetuates the upheld systemic inflammatory state in cardiovascular disease (CVD) which is common in other chronic inflammatory diseases (CID).

The objectives of the REPROGRAM project:
1. To unravel the molecular mechanisms through which systemic risk factors for CVD elicit trained immunity of innate immune cells, focussing on monocytes, macrophages and hematopoietic stem and progenitor cells.
2. To assess the relevance of TI as a common mechanism for the development of disease-specific pathophysiology, and its role in the development of co-morbidities in both women and men.
3. To investigate the role of TI in atherosclerotic CVD and CID.
4. To evaluate whether modulation of TI will lead to a reduction of the pro-inflammatory state both in atherosclerosis and CID, offering innovative immune-modulatory therapeutic strategies.
In WP2, we aimed to detail the effect of cardiovascular risk factors on epigenetic changes in immune cells, establish its impact on atherosclerosis and investigate its therapeutic potential. Our studies have revealed that factors modulating CVD, including diet and exercise indeed affect the proliferative and differentiation capacity of hematopoietic stem and progenitor cells in the bone marrow, and of myeloid cells in lymphoid organs and in the circulation, thereby affecting the outcome of atherosclerosis. Moreover, we have also found that tissue macrophages have their tissue specific function and reactivity, depending on the event or disease. Our studies have revealed novel processes and (epigenetic) modifiers that mediate myeloid cell fate and activation in CVD, and we have investigated the therapeutic potential some of these candidates. Moreover, we have developed a small molecule inhibitor against an important modifier of inflammation (CD40-TRAF6), and were able to show that this drug could decrease atherosclerosis in a laboratory setting. In order to specifically target our new drug to macrophages, we developed a nanomedicinal delivery strategy and could successfully develiver our drug to macrophages and reduce atherosclerosis.

Cells of the innate immune system, including monocytes and macrophages, importantly contribute to the development of atherosclerotic CVD. We recently identified that these cells can build a long-term immunological memory, which is called trained immunity (TI), that results in a pro-atherogenic phenotype. In WP3, we aimed to identify drivers of TI and elucidate underlying mechanisms, including metabolic and epigenetic reprogramming with the ultimate aim to identify novel pharmacological targets. In an in vitro model of trained immunity in human myeloid cells, we identified various relevant stimuli that can induce trained immunity, including oxidized LDL, lipoprotein (a), catecholamines, aldosterone. Using transcriptomic, epigenomic, and metabolic approaches, we identified various metabolic and epigenetic mechanisms that are key to TI which can be used as novel targets for pharmacotherapy. In animal models of athesclerosis, we identified that dyslipidemia and hyperglycemia induces long-term reprogramming of the innate immune system by an effect on bone marrow progenitors. This was validated in humans with dyslipidemia and established atherosclerosis.

In WP4, we first identified a list of SNPs which correlated with trained immunity in monocytes in healthy volunteers. We assessed the predictive value of this ‘epigenetic’ gene risk score on CV-risk in the general population (Copenhagen General Population Study). Of the SNPs associated with trained immunity, none were convincingly associated with CVD-risk. We subsequently evaluated DNA-methylation, which is a more stable sign of epigenetic changes. We also addressed the reversibility of epigenetic remodeling by lowering of ‘traditional’ lipid risk factors in relation to inflammatory activity, assessed as plasma cytokines, immune cell phenotype of circulating cells and vascular wall inflammation. In various patient cohorts, we substantiated a multi-level pro-inflammatory state, ranging from all the way from bone-marrow, plasma immune cells to the arterial wall. In subsequent intervention studies, we were able to unravel the differential regulation of immune cell activation on various target levels. Furthermore we initiated a clinical study to address the impact of an epigenetic modulator on inflammatory activity in humans (oral methylbutyrate intake). In parallel, we conducted a clinical study to investigate the impact of the bromodomain inhibitor (RVX-208) on the inflammatory state in type 2 diabetes mellitus patients.

Monocytes and macrophages play a central role in the pathophysiology of inflammation, as well as in atherosclerosis. In WP5, it was found that these are activated in rheumatoid arthritis (RA), to massively infiltrate synovial t
Expected results until the end of the project
New epigenetic modulating therapies for the treatment of atherosclerosis and other chronic inflammatory diseases, combined with new mechanistic insights, will have a durable effect on improving treatment effects, life expectancy, quality of life, and avoiding unnecessary treatments. Thereby, by targeting trained immunity from a broader disease perspective in terms of a potential common mechanism for several non-communicable diseases (such as rheumatoid arthritis), the window of opportunity can be even greater by the execution of a innovative project like the REPROGRAM project.

Potential impact
The REPROGRAM project attempts to dissect novel disease pathways and treatment options under alternative research programs in cooperation with biotech and pharmaceutical companies. The generated knowledge will also provide clues to the biology of ageing as exemplified by the age-associated variation of expression of distinct biomarkers. The epidemiological analysis of these molecular markers in large population cohorts will enable to compare patients of different sexes and ages and to reveal ageing-related pathophysiological changes. Thus, the REPROGRAM project would constitute a major societal advancement in addressing the health and well-being of the European population, especially (but not only) in the quality of life of the increasing proportion of older persons prone to these debilitating diseases.
Conceptual framework of REPROGRAM