Mevalonate kinase deficiency (MKD) is a rare inborn auto-inflammatory disease due to the impairment of the pathway for the biosynthesis of cholesterol and non-sterol isoprenoids. The shortage of isoprenoids compounds and in particular of geranylgeranylpyrophosphate (GGPP) was recently associated to the MKD characteristic inflammatory attacks. The aim of this study is to demonstrate that the normalization of the mevalonate pathway intermediates levels and in particular of GGPP, through the specific inhibition of farnesyl-transferase (FT) with Manumycin A could ameliorate the inflammatory phenotype of MKD patients. The effect of Manumycin A was first evaluated in MKD mouse and cellular models, chemically obtained using the aminobisphosphonate alendronate (ALD), and then in monocytes isolated from 2 MKD patients. Our findings were compared to those obtained by using natural exogenous isoprenoids (NEIs). Manumycin A was able to significantly reduce the inflammatory marker serum amyloid A in ALD-treated Balb/c mice, as well as IL-1 beta secretion in ALD-monocytes and in MKD patients. These results clearly showed that, through the inhibition of FT, an increased number of mevalonate pathway intermediates could be redirected towards the synthesis of GGPP diminishing the inflammatory response. The importance in limiting the shortage of GGPP was emphasized by the anti-inflammatory effect of NEIs that, due to their biochemical structure, can enter the MKD pathway. In conclusion, manumycin A, as well as NEIs, showed anti-inflammatory effect in MKD models and especially in MKD-monocytes, suggesting novel approaches in the treatment of MKD, an orphan disease without any efficacious treatment currently available.
"On the other hand, farnesylation inhibitors can reduce the consumption of farnesyl pyrophosphate , augmenting the geranylgeranyl pyrophosphate available for the geranylgeranylation pathway   (Figure 1). We previously suggested that plant isoprenoids  and inhibitors of farnesylation  could represent a potential specific pharmacologic approach for MKD; however we did not yet consider how the temperature could act on the antiinflammatory effect of these compounds in MKD. "
[Show abstract][Hide abstract] ABSTRACT: Mevalonate Kinase Deficiency (MKD) is a rare autosomal recessive inborn disorder of cholesterol biosynthesis caused by mutations in the mevalonate kinase (MK) gene, leading to MK enzyme decreased activity. The consequent shortage of mevalonate-derived isoprenoid compounds results in an inflammatory phenotype, caused by the activation of the NALP3 inflammasome that determines an increased caspase-1 activation and IL-1 β release. In MKD, febrile temperature can further decrease the residual MK activity, leading to mevalonate pathway modulation and to possible disease worsening. We previously demonstrated that the administration of exogenous isoprenoids such as geraniol or the modulation of the enzymatic pathway with drugs, such as Tipifarnib, partially rescues the inflammatory phenotype associated with the defective mevalonic pathway. However, it has not been investigated yet how temperature can affect the success of these treatments. Thus, we investigated the effect of temperature on primary human monocytes from MKD patients. Furthermore the ability of geraniol and Tipifarnib to reduce the abnormal inflammatory response, already described at physiological temperature in MKD, was studied in a febrile condition. We evidenced the role of temperature in the modulation of the inflammatory events and suggested strongly considering this variable in future researches aimed at finding a treatment for MKD.
"Ubiquinone is an antioxidant molecule that plays a crucial role in the respiratory chain, while Bax is required to permeabilize the mitochondrial outer membrane during apoptosis (Campia et al., 2009; Herrero-Martin and Lòpez-Rivas, 2008). Exogenous isoprenoids, such as geranylgeraniol, are able to enter the mevalonate pathway, to be metabolized by the FPPS and to rescue the shortage of intermediate isoprenoids in MKD models (De Leo et al., 2010). We already demonstrated that increased programmed cell death (PCD), and not only IL-1ß production, is caused by the mevalonate pathway inhibition: our study showed that cell death, induced by the block of the pathway, was in part sustained by the activation of caspase-3 and partially of caspase-1 (Marcuzzi et al., 2010, 2011). "
[Show abstract][Hide abstract] ABSTRACT: Mevalonic aciduria (MA), the most severe form of mevalonate kinase deficiency (MKD), is still an orphan drug disease and the pathogenetic mechanisms underlying neuronal dysfunction is still poorly understood. In our study we have investigated the apoptotic mechanism mediated by the exposure of the cultured neuroblastoma cell line, SH-SY5Y, to lovastatin in absence or in presence of the isoprenoid, geranylgeraniol, with the aim of unraveling the pathogenesis of MA. Lovastatin, blocks the mevalonate pathway inhibiting the 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CR), an enzyme of the mevalonate pathway upstream the mevalonate kinase enzyme, reproducing biochemical features similar to those found in MKD. We demonstrate that apoptosis in neuronal lovastatin treated-cells is induced by the mitochondrial pathway, with caspase-9 as the initiator and caspase-3 as the effector caspase. The presence of geranylgeraniol modulates both the caspase-9 and caspase-3 activity in a dose-dependent way, confirming that this isoprenoid enters the mevalonate pathway, is metabolized and finally is able to by-pass the statin biochemical block reconstituting the mevalonate pathway. According to our findings, it should not be the time course adopted that modulates the apoptotic response but rather the isoprenoid itself. Being aware that our results have been obtained using a biochemical model of MKD, and not cells from patients with the disease, we believe our findings increase the knowledge of MA pathogenesis, and may possibly contribute to the development of novel therapeutic strategies.
International journal of developmental neuroscience: the official journal of the International Society for Developmental Neuroscience 06/2012; 30(6):451-6. DOI:10.1016/j.ijdevneu.2012.06.002 · 2.58 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This review describes the mouse knockout models of cholesterol synthesis, together with human malformations and drugs that target cholesterogenic enzymes. Generally, the sooner a gene acts in cholesterol synthesis, the earlier the phenotype occurs. Humans with loss of function of early cholesterogenic enzymes have not yet been described, and in the mouse, loss of Hmgcr is preimplantation lethal. Together, these results indicate that the widely prescribed cholesterol-lowering statins are potentially teratogenic. The Mvk knockout is early embryonic lethal in the mouse, the absence of Fdft1 is lethal at E9.5-12.5 dpc, while the Cyp51 knockouts die at 15.0 dpc. Fungal CYP51 inhibitor azoles are teratogenic in humans, potentially leading to symptoms of Antley-Bixler syndrome. The X-linked mutations in Nsdhl and Ebp are embryonic lethal in male mice, while heterozygous females are also affected. Consequently, the anticancer drugs, tamoxifen and toremifene, inhibiting human EBP, may be harmful in early pregnancy. The Dhcr7 and Dhcr24 knockout mice die shortly after birth, while humans survive with Smith-Lemli-Opitz syndrome or desmosterolosis. Since cholesterol is essential for hedgehog signaling, disturbance of this pathway by antipsychotics and -depressants explains some drug side effects. In conclusion, defects in cholesterol synthesis are generally lethal in mice, while humans with impaired later steps of the pathway can survive with severe malformations. Evidence shows that drugs targeting or, by coincidence, inhibiting human cholesterol synthesis are better avoided in early pregnancy. Since some drugs with teratogenic potential still stay on the market, this should be avoided in new cholesterol-related drug development.
Drug Metabolism Reviews 02/2011; 43(1):69-90. DOI:10.3109/03602532.2010.540580 · 5.36 Impact Factor
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