Supplementary Material for: Autoimmune Disease-Associated Variants of Extracellular Endoplasmic Reticulum Aminopeptidase 1 Induce Altered Innate Immune Responses by Human Immune Cells

Endoplasmic reticulum aminopeptidase 1 <i>(ERAP1)</i> gene polymorphisms have been linked to several autoimmune diseases; however, the molecular mechanisms underlying these associations are not well understood. Recently, we demonstrated that ERAP1 regulates key aspects of the innate immune response. Previous studies show ERAP1 to be endoplasmic reticulum-localized and secreted during inflammation. Herein, we investigate the possible roles that ERAP1 polymorphic variants may have in modulating the innate immune responses of human peripheral blood mononuclear cells (hPBMCs) using two experimental methods: extracellular exposure of hPBMCs to ERAP1 variants and adenovirus (Ad)-based ERAP1 expression. We found that exposure of hPBMCs to ERAP1 variant proteins as well as ERAP1 overexpression by Ad5 vectors increased inflammatory cytokine and chemokine production, and enhanced immune cell activation. Investigating the molecular mechanisms behind these responses revealed that ERAP1 is able to activate innate immunity via multiple pathways, including the NLRP3 (NOD-like receptor, pyrin domain-containing 3) inflammasome. Importantly, these responses varied if autoimmune disease-associated variants of ERAP1 were examined in the assay systems. Unexpectedly, blocking ERAP1 cellular internalization augmented IL-1β production. To our knowledge, this is the first report identifying ERAP1 as being involved in modulating innate responses of human immune cells, a finding that may explain why ERAP1 has been genetically associated with several autoimmune diseases

Breast cancer hypothesis: a single cause for the majority of cases

STUDY OBJECTIVE—The main cause of breast cancer remains unknown. Numerous causal factors or predisposing conditions have been proposed, but account for only a small percentage of the total disease. The current search for multiple causes is unavailing. This report explores whether any single aetiological agent may be responsible for the majority of cases, and attempts to define its properties.
METHODS—Examination of all relevant epidemiological and biological evidence.
MAIN RESULTS—Genetic inheritance is not the main cause of breast cancer because most cases are sporadic, there is a low prevalence of family history, and genetically similar women have differing rates after migration. Environmental exposure, such as pollution by industrialisation, is not a major cause, as deduced from a spectrum of epidemiological data. The possibility of infection as cause is not persuasive as there is no direct biological evidence and no epidemiological support. Oestrogen status is closely related to breast cancer risk, but there are numerous inconsistencies and paradoxes. It is suggested that oestrogens are not the proximate agent but are promoters acting in concert with the causal agent. Dietary factors, and especially fat, are associated with the aetiology of breast cancer as shown by intervention and ecological correlation studies, but the evidence from case-control and cohort studies is inconsistent and contradictory.
CONCLUSIONS—The hypothesis that best fits the epidemiological data is that dietary fat is not itself the causal agent, but produces depletion of an essential factor that is normally protective against the development of breast cancer. Many of the observed inconsistencies in the epidemiology are explainable if deficiency of this agent is permissive for breast cancer to develop. Some properties of the putative agent are outlined, and research investigations proposed.


Keywords: breast cance