Biosynthesis of steroids from squalene

There have been attempts to link squalene to Gulf War Syndrome mainly due to the idea that squalene might have been present in an anthrax vaccine given to some military personnel during the 1991 Persian Gulf War. Studies found that deployed Persian Gulf War Syndrome patients are significantly more likely to have antibodies to squalene (95 percent) than asymptomatic Gulf War veterans (0 percent; p<.001). [20] [21] The first of these published results concludes with the following statement: "It is important to note that our laboratory-based investigations do not establish that squalene was added as adjuvant to any vaccine used in military or other personnel who served in the Persian Gulf War era." The second publication, however, links the incidence of anti-squalene antibodies and Gulf War Syndrome to five specific lots of vaccine. Furthermore, they cite results of 1999 testing by the . Food and Drug Administration which found these specific lots of vaccine to contain squalene. [22] In response to these results, a committee of the US Institute of Medicine stated that "The committee does not regard this study as providing evidence that the investigators have successfully measured antibodies to squalene", since the authors did not perform the normal scientific controls needed to show that their test was specific to anti-squalene antibodies. [23] It has also been determined that the anthrax vaccines given to those US military personnel did not use squalene as an adjuvant. [24] [25] [26] The vaccines were also tested for squalene, and none was detected with standard methods. [27] Another method found no squalene in 37 of the 38 lots tested. One lot contained traces of squalene, at less than ten parts per billion, which is about one-thirtieth the level found in human blood. [28] The FDA stated that this trace of squalene probably came from a fingerprint, since the oils on human skin contain enough squalene to send these extremely sensitive tests "off the chart". [29]

Iron homeostasis is tightly regulated by the membrane iron exporter ferroportin and its regulatory peptide hormone hepcidin. The hepcidin/ferroportin axis is considered a promising therapeutic target for the treatment of diseases of iron overload or deficiency. Here, we conducted a chemical screen in zebrafish to identify small molecules that decrease ferroportin protein levels. The chemical screen led to the identification of 3 steroid molecules, epitiostanol, progesterone, and mifepristone, which decrease ferroportin levels by increasing the biosynthesis of hepcidin. These hepcidin-inducing steroids (HISs) did not activate known hepcidin-inducing pathways, including the BMP and JAK/STAT3 pathways. Progesterone receptor membrane component-1 (PGRMC1) was required for HIS-dependent increases in hepcidin biosynthesis, as PGRMC1 depletion in cultured hepatoma cells and zebrafish blocked the ability of HISs to increase hepcidin mRNA levels. Neutralizing antibodies directed against PGRMC1 attenuated the ability of HISs to induce hepcidin gene expression. Inhibiting the kinases of the SRC family, which are downstream of PGRMC1, blocked the ability of HISs to increase hepcidin mRNA levels. Furthermore, HIS treatment increased hepcidin biosynthesis in mice and humans. Together, these data indicate that PGRMC1 regulates hepcidin gene expression through an evolutionarily conserved mechanism. These studies have identified drug candidates and potential therapeutic targets for the treatment of diseases of abnormal iron metabolism.

Biosynthesis of steroids from squalene

biosynthesis of steroids from squalene


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