-
Neural Regeneration Research Feb 2022Cholesterol is biosynthesized by all animal cells. Beyond its metabolic role in steroidogenesis, it is enriched in the plasma membrane where it has key structural and... (Review)
Review
Cholesterol is biosynthesized by all animal cells. Beyond its metabolic role in steroidogenesis, it is enriched in the plasma membrane where it has key structural and regulatory functions. Cholesterol is thus presumably important for post-injury axon regrowth, and this notion is supported by studies showing that impairment of local cholesterol reutilization impeded regeneration. However, several studies have also shown that statins, inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase, are enhancers of axon regeneration, presumably acting through an attenuation of the mevalonate isoprenoid pathway and consequent reduction in protein prenylation. Several recent reports have now shown that cholesterol depletion, as well as inhibition of cholesterol synthesis per se, enhances axon regeneration. Here, I discussed these findings and propose some possible underlying mechanisms. The latter would include possible disruptions to axon growth inhibitor signaling by lipid raft-localized receptors, as well as other yet unclear neuronal survival signaling process enhanced by cholesterol lowering or depletion.
PubMed: 34269187
DOI: 10.4103/1673-5374.317956 -
Advances in Experimental Medicine and... 2018UNC119 and PDEδ are lipid-binding proteins and are thought to form diffusible complexes with transducin-α and prenylated OS proteins, respectively, to mediate their... (Review)
Review
UNC119 and PDEδ are lipid-binding proteins and are thought to form diffusible complexes with transducin-α and prenylated OS proteins, respectively, to mediate their trafficking to photoreceptor outer segments. Here, we investigate mechanisms of trafficking which are controlled by Arf-like protein 3 (Arl3), a small GTPase. The activity of ARL3 is regulated by a GEF (ARL13b) and a GAP (RP2). In a mouse germline knockout of RP2, ARL3-GTP is abundant as its intrinsic GTPase activity is extremely low. High levels of ARL3-GTP impair binding and trafficking of cargo to the outer segment. Germline knockout of ARL3 is embryonically lethal generating a syndromic ciliopathy-like phenotype. Retina- and rod-specific knockout of ARL3 allow to determine the precise mechanisms leading to photoreceptor degeneration. The knockouts reveal binary functions of ARL3-GTP as a key molecule in late-stage photoreceptor ciliogenesis and cargo displacement factor.
Topics: ADP-Ribosylation Factors; Adaptor Proteins, Signal Transducing; Animals; Ciliopathies; Cone-Rod Dystrophies; Cyclic Nucleotide Phosphodiesterases, Type 6; GTP-Binding Proteins; Genes, Lethal; Guanosine Triphosphate; Lipoproteins; Membrane Proteins; Mice; Mice, Knockout; Organ Specificity; Protein Prenylation; Protein Transport; Pyrophosphatases; Rod Cell Outer Segment
PubMed: 29721959
DOI: 10.1007/978-3-319-75402-4_39 -
Expert Opinion on Therapeutic Patents May 2019Bisphosphonates (BPs) are widely used to manage a variety of bone disorders, including osteoporosis, metastatic bone disease and myeloma bone disease. The... (Review)
Review
INTRODUCTION
Bisphosphonates (BPs) are widely used to manage a variety of bone disorders, including osteoporosis, metastatic bone disease and myeloma bone disease. The nitrogen-containing BPs (NBPs) target osteoclast activity by disrupting protein prenylation via inhibition of farnesyl diphosphate synthase (FDPS).
AREAS COVERED
This review summarizes the recent advances in BPs with a focus on the latest patents (2015-2018). Patents involving novel BPs, new modes of BP delivery, as well as use of BPs to deliver other drugs to bone are discussed. A review of phosphonate-based drugs targeting geranylgeranyl diphosphate synthase (GGDPS) or geranylgeranyl transferase II (GGTase II) as alternative strategies to disrupt protein geranylgeranylation is provided.
EXPERT OPINION
While the NBPs remain the mainstay of treatment for most bone disorders, further understanding of their pharmacological properties could lead to further refinement of their chemical structures and optimization of efficacy and safety profiles. In addition, the development of NBP analogs or drug delivery mechanisms that allow for nonbone tissue exposure could allow for the use of these drugs as direct anticancer agents. The development of GGDPS and GGTase II inhibitors represents alternative heterocycle phosphonate-based strategies to disrupt protein geranylgeranylation and may have potential as anticancer agents and/or as bone-targeted therapies.
Topics: Animals; Bone Diseases; Diphosphonates; Drug Delivery Systems; Drug Development; Farnesyltranstransferase; Geranyltranstransferase; Humans; Osteoclasts; Patents as Topic; Protein Prenylation; Transferases
PubMed: 31023104
DOI: 10.1080/13543776.2019.1608180 -
International Journal of Molecular... Dec 2022Multiple myeloma (MM) is a plasma cell malignancy for which there is currently no cure. While treatment options for MM have expanded over the last two decades, all... (Review)
Review
Multiple myeloma (MM) is a plasma cell malignancy for which there is currently no cure. While treatment options for MM have expanded over the last two decades, all patients will eventually become resistant to current therapies. Thus, there is an urgent need for novel therapeutic strategies to treat MM. The isoprenoid biosynthetic pathway (IBP) is responsible for the post-translational modification of proteins belonging to the Ras small GTPase superfamily, such as Ras, Rho and Rab family members. Given the important roles these GTPase proteins play in various cellular processes, there is significant interest in the development of inhibitors that disturb their prenylation and consequently their activity in MM cells. Numerous preclinical studies have demonstrated that IBP inhibitors have anti-MM effects, including the induction of apoptosis in MM cells and inhibition of osteoclast activity. Some IBP inhibitors have made their way into the clinic. For instance, nitrogenous bisphosphonates are routinely prescribed for the management MM bone disease. Other IBP inhibitors, including statins and farnesyltransferase inhibitors, have been evaluated in clinical trials for MM, while there is substantial preclinical investigation into geranylgeranyl diphosphate synthase inhibitors. Here we discuss recent advances in the development of IBP inhibitors, assess their mechanism of action and evaluate their potential as anti-MM agents.
Topics: Humans; Multiple Myeloma; Biosynthetic Pathways; Diphosphonates; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Terpenes; Protein Prenylation
PubMed: 36613550
DOI: 10.3390/ijms24010111 -
The Journal of Biological Chemistry Oct 2023Emerging research and clinical evidence suggest that the metabolic activity of oocytes may play a pivotal role in reproductive anomalies. However, the intrinsic...
Emerging research and clinical evidence suggest that the metabolic activity of oocytes may play a pivotal role in reproductive anomalies. However, the intrinsic mechanisms governing oocyte development regulated by metabolic enzymes remain largely unknown. Our investigation demonstrates that geranylgeranyl diphosphate synthase1 (Ggps1), the crucial enzyme in the mevalonate pathway responsible for synthesizing isoprenoid metabolite geranylgeranyl pyrophosphate from farnesyl pyrophosphate, is essential for oocyte maturation in mice. Our findings reveal that the deletion of Ggps1 that prevents protein prenylation in fully grown oocytes leads to subfertility and offspring metabolic defects without affecting follicle development. Oocytes that lack Ggps1 exhibit disrupted mitochondrial homeostasis and the mitochondrial defects arising from oocytes are inherited by the fetal offspring. Mechanistically, the excessive farnesylation of mitochondrial ribosome protein, Dap3, and decreased levels of small G proteins mediate the mitochondrial dysfunction induced by Ggps1 deficiency. Additionally, a significant reduction in Ggps1 levels in oocytes is accompanied by offspring defects when females are exposed to a high-cholesterol diet. Collectively, this study establishes that mevalonate pathway-protein prenylation is vital for mitochondrial function in oocyte maturation and provides evidence that the disrupted protein prenylation resulting from an imbalance between farnesyl pyrophosphate and geranylgeranyl pyrophosphate is the major mechanism underlying impairment of oocyte quality induced by high cholesterol.
PubMed: 37611828
DOI: 10.1016/j.jbc.2023.105183 -
The Journal of Pathology Mar 2019Non-alcoholic fatty liver disease (NAFLD) often develops in concert with related metabolic diseases, such as obesity, dyslipidemia and insulin resistance. Prolonged...
Non-alcoholic fatty liver disease (NAFLD) often develops in concert with related metabolic diseases, such as obesity, dyslipidemia and insulin resistance. Prolonged lipid accumulation and inflammation can progress to non-alcoholic steatohepatitis (NASH). Although factors associated with the development of NAFLD are known, triggers for the progression of NAFLD to NASH are poorly understood. Recent findings published in The Journal of Pathology reveal the possible regulation of NASH progression by metabolites of the mevalonate pathway. Mevalonate can be converted into the isoprenoids farnesyldiphosphate (FPP) and geranylgeranyl diphosphate (GGPP). GGPP synthase (GGPPS), the enzyme that converts FPP to GGPP, is dysregulated in humans and mice during NASH. Both FPP and GGPP can be conjugated to proteins through prenylation, modifying protein function and localization. Deletion or knockdown of GGPPS favors FPP prenylation (farnesylation) and augments the function of liver kinase B1, an upstream kinase of AMP-activated protein kinase (AMPK). Despite increased AMPK activation, livers in Ggpps-deficient mice on a high-fat diet poorly oxidize lipids due to mitochondrial dysfunction. Although work from Liu et al provides evidence as to the potential importance of the prenylation portion of the mevalonate pathway during NAFLD, future studies are necessary to fully grasp any therapeutic or diagnostic potential. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Topics: Animals; Diet, High-Fat; Farnesyltranstransferase; Fibrosis; Glucose; Humans; Liver; Mice; Non-alcoholic Fatty Liver Disease; Prenylation; United Kingdom
PubMed: 30374976
DOI: 10.1002/path.5190 -
International Journal of Molecular... Jul 2015The mevalonate pathway, crucial for cholesterol synthesis, plays a key role in multiple cellular processes. Deregulation of this pathway is also correlated with... (Review)
Review
The mevalonate pathway, crucial for cholesterol synthesis, plays a key role in multiple cellular processes. Deregulation of this pathway is also correlated with diminished protein prenylation, an important post-translational modification necessary to localize certain proteins, such as small GTPases, to membranes. Mevalonate pathway blockade has been linked to mitochondrial dysfunction: especially involving lower mitochondrial membrane potential and increased release of pro-apoptotic factors in cytosol. Furthermore a severe reduction of protein prenylation has also been associated with defective autophagy, possibly causing inflammasome activation and subsequent cell death. So, it is tempting to hypothesize a mechanism in which defective autophagy fails to remove damaged mitochondria, resulting in increased cell death. This mechanism could play a significant role in Mevalonate Kinase Deficiency, an autoinflammatory disease characterized by a defect in Mevalonate Kinase, a key enzyme of the mevalonate pathway. Patients carrying mutations in the MVK gene, encoding this enzyme, show increased inflammation and lower protein prenylation levels. This review aims at analysing the correlation between mevalonate pathway defects, mitochondrial dysfunction and defective autophagy, as well as inflammation, using Mevalonate Kinase Deficiency as a model to clarify the current pathogenetic hypothesis as the basis of the disease.
Topics: Autophagy; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Mevalonate Kinase Deficiency; Mevalonic Acid; Mitochondria; Phosphotransferases (Alcohol Group Acceptor); Protein Prenylation; TOR Serine-Threonine Kinases
PubMed: 26184189
DOI: 10.3390/ijms160716067 -
Molecular Neurobiology Dec 2016Isoprenylation is a posttranslational modification that transfers farnesyl pyrophosphate (FPP) or geranylgeranyl pyrophosphate (GGPP) to cysteine residues of a... (Review)
Review
Isoprenylation is a posttranslational modification that transfers farnesyl pyrophosphate (FPP) or geranylgeranyl pyrophosphate (GGPP) to cysteine residues of a particular set of proteins, causing their localization to the plasma membrane and other cellular compartments and so rendering them biologically active. Such a modification process, catalyzed by protein prenyltransferase including farnesyltransferase (FT), geranylgeranyltransferase I (GGTI), and geranylgeranyltransferase II (GGTII), is required for the transforming activity of many oncogenic proteins, including some RAS family members. In the past three decades, prenyltransferase has been extensively studied as a promising cancer therapeutic target in vitro, in animal models, and in the clinic. Recently, a growing number of studies suggest that prenyltransferases and the substrates FPP and GGPP also play fundamental roles in nervous system development and brain disorders. However, a systemic review about the advances of prenyltransferases in the field of neuroscience is lacking so far. Herein, we give a brief introduction for the structure and distribution of GGTI and comprehensively updated the recent advances of GGTI in neuronal dendritogenesis/synaptogenesis and in learning/memory-related behavioral performance. More importantly, we discussed the involvement of GGTI and its substrate GGPP in neurodegenerative disorders, such as aging, Alzheimer's disease, multiple sclerosis, and Niemann-Pick disease type C. The role of FT-FPP and GGTII is mentioned as well to compare with GGTI in these physiological and pathological processes. We hope that this systematical review about what we know about GGTI research in the brain can stimulate further studies on the underlying mechanism of GGTI-mediated isoprenylation in the pathogenesis of neurodegenerative and neurodevelopmental disorders.
Topics: Aging; Alkyl and Aryl Transferases; Animals; Brain; Dendrites; Humans; Neurogenesis; Protein Prenylation
PubMed: 26666664
DOI: 10.1007/s12035-015-9594-3 -
BioRxiv : the Preprint Server For... Oct 2023Low-density lipoprotein cholesterol (LDL-C) lowering is the main goal of atherosclerotic cardiovascular disease prevention, and proprotein convertase subtilisin/kexin...
Low-density lipoprotein cholesterol (LDL-C) lowering is the main goal of atherosclerotic cardiovascular disease prevention, and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition is now a validated therapeutic strategy that lowers serum LDL-C and reduces coronary events. Ironically, the most widely used medicine to lower cholesterol, statins, has been shown to increase circulating PCSK9 levels, which limits their efficacy. Here, we show that geranylgeranyl isoprenoids and hepatic Rap1a regulate both basal and statin induced expression of PCSK9 and contribute to LDL-C homeostasis. Rap1a prenylation and activity is inhibited upon statin treatment, and statin mediated PCSK9 induction is dependent on geranylgeranyl synthesis and hepatic Rap1a. Accordingly, treatment of mice with a small molecule activator of Rap1a lowered PCSK9 protein and plasma cholesterol and inhibited statin mediated PCSK9 induction in hepatocytes. The mechanism involves inhibition of the downstream RhoA-ROCK pathway and regulation of PCSK9 at the post transcriptional level. These data further identify Rap1a as a novel regulator of PCSK9 protein and show that blocking Rap1a prenylation through lowering geranylgeranyl levels contributes to statin-mediated induction of PCSK9.
PubMed: 37961667
DOI: 10.1101/2023.10.23.563509 -
Journal of Internal Medicine Aug 2020The RAS genes, which include H, N, and KRAS, comprise the most frequently mutated family of oncogenes in cancer. Mutations in KRAS - such as the G12C mutation - are... (Review)
Review
The RAS genes, which include H, N, and KRAS, comprise the most frequently mutated family of oncogenes in cancer. Mutations in KRAS - such as the G12C mutation - are found in most pancreatic, half of colorectal and a third of lung cancer cases and is thus responsible for a substantial proportion of cancer deaths. Consequently, KRAS has been the subject of exhaustive drug-targeting efforts over the past 3-4 decades. These efforts have included targeting the KRAS protein itself but also its posttranslational modifications, membrane localization, protein-protein interactions and downstream signalling pathways. Most of these strategies have failed and no KRAS-specific drugs have yet been approved. However, for one specific mutation, KRAS , there is light on the horizon. MRTX849 was recently identified as a potent, selective and covalent KRAS inhibitor that possesses favourable drug-like properties. MRTX849 selectively modifies the mutant cysteine residue in GDP-bound KRAS and inhibits GTP-loading and downstream KRAS-dependent signalling. The drug inhibits the in vivo growth of multiple KRAS -mutant cell line xenografts, causes tumour regression in patient-derived xenograft models and shows striking responses in combination with other agents. It has also produced objective responses in patients with mutant-specific lung and colorectal cancer. In this review, we discuss the history of RAS drug-targeting efforts, the discovery of MRTX849, and how this drug provides an exciting and long-awaited opportunity to selectively target mutant KRAS in patients.
Topics: Antineoplastic Agents; Clinical Trials as Topic; Enzyme Inhibitors; Humans; Mutation; Neoplasms; Protein Prenylation; Proto-Oncogene Proteins p21(ras)
PubMed: 32176377
DOI: 10.1111/joim.13057