Molecular Interventions for Cardiovascular Disease:It Isn't That Simple!A Cautionary TaleCauses of death, 2001:1. Infectious and parasitic diseases: 14.9 million2. Heart diseases: 11.1 million3. Cancers: 7.3 million4. Stroke: 5.5 million5. Respiratory diseases: 3.6 million6. Accidents, fires, drowning, etc.: 3.5 million7. Maternal and perinatal: 3.0 million8. Violence (war, homicide, suicide): 1.6 million World Health OrganizationWorld Health Report 2002Population: 6,122,210,000Deaths: 56,554,000USA6.1.2.3.4.5.AtherosclerosisRisk increases with higher [LDL]Risk decreases with higher [HDL]Familial Hypercholesterolemia (FH)XanthomaHeterozygotes (1:500) 300-500 mg/dl plasma cholesterol Xanthomas in third decade Coronary heart disease in fourth decade Treat w/ statins and bile acid binding resinsHomozygotes (1:10^6) 500-1200 mg/dl plasma cholesterol Xanthomas at birth Death by MI before age 30 Treat w/ plasma LDL apheresisCholesterol1) Acetyl-CoA → HMG-CoA → Mevalonate2) Mevalonate (C6) + 3ATP → Isopentenyl-PPi (C5 “isoprene”) + CO2 + 3ADP + Pi3) 6 Isoprene units (C5) → Squalene (C30)4) Squalene (C30) → Cholesterol (C27)Isopentylpyrophosphate (MEV Pathway)Lipid Trafficking EnzymesAlso CETPLipoprotein ParticlesCMC, VLDL, IDL, HDL; bindsreceptor0.03-0.0538 kDApoEHDL0.06-0.0733 kDApoDCMC, VLDL, HDL0.12-0.149 kDApoC-IIICMC, VLDL, HDL; activates LPL0.03-0.059 kDApoC-IICMC, VLDL, HDL0.04-0.067 kDApoC-IVLDL, IDL, LDL; binds receptor0.7-1.0512 kDApoB-100CMC; (intestine only)0.03-0.05264 kDApoB-48CMC, HDL0.15-0.1646 kDApoA-IVCMC, HDL0.3-0.517 kDApoA-IICMC, HDL; activates LCAT1.0-1.228 kDApoA-ICommentsgL-1M.W.ApolipoproteinFRAMINGHAM HEART STUDY 1977For each 1% decrease in [LDL], get an ~1% decrease in RR of CAD mortality.For each 1% increase in [HDL], get a 1.3-3% decrease in RR of CAD mortality.These are independent effects.Lipoprotein TransportTrans-Membrane Transport: ABC Transporters• The A1 and G1 ABC transportersmove cholesterol across PM's• Cholesterol returns to the liver viaHDL and LDL• Largest bacterial protein family(5% of E. coli proteome)• Two ATP binding cassettes thatdimerize in an ATP-gated fashion• MDR pump is an ABC transporter• The TAP pore responsible forMHCI presentation is an ABC tp.• cf C.F.Intracellular Transport: Niemann-Pick Diease• Niemann-Pick A..E is a set of five inheritedlysosomal storage diseases.• Neurodegeneration (dramatic loss of Purkinje cells)and liver failure; death in childhood.• Recessive disease with 1 in 150,000 incidence; inYarmouth County Nova Scotia 1% with carier 25%.• Cholesterol and sphingolipids accumulate in lateendosomes and lysosomes of cells; can be observedin vitro by loading fibroblasts with LDL.• Types A and B from defects in lysosomalsphingomyelinase.• Type C genes located in 1997/2000; two proteinsNPC1 (membrane) and NPC2 (soluble).• These proteins appear to transport cholesterol out ofendosomes and into the cell cytoplasm.• In NPC cells, cholesterol synthesis is upregulated (viaSREBP).NPC 1INTERVENTION STRATEGY #1: Lower [LDL]#1A: The StatinsSHORT HISTORY• 1976 Mevastatin fromPenicillinum citrinum•1980 Mevinolin fromAspergillus terreus•1987 FDA approvesLovastatin•1988 Lovastatin not effectivein FH homozygotes•1995 Pravastatin decreasesheart transplant rejection andmortality independently oflowering cholesterol levelsSTATINS REDUCE [CIRCULATING CHOLESTEROL] BY UP TO 50%FAIRLY SAFE (rhabdomyolysis)IDEA:Statins act by inhibiting cholesterol synthesisin patients.Clinical ObservationUauy et al. Journal of Pediatrics 113(2): 7387-92 (1988).Sterol Regulation of Transcription by SREBPSREPB Transcription Factor LocalizationER Retention ProteasesE.R.E.R. Golgi.Golgi.NucleusSCAP/Insig proteinsalso (HMG CoA R)S1P S2PSSDGoldstein will talk inthe Frontiers series onWednesday Oct. 222008, Clark CenterAuditorium, 4:00 P.M.IDEA:Statins act by activating SREBP, resulting inincreased LDL receptor and more efficientrecruitment of LDL out of plasma.Clinical Observations:The Pleiotrophic Effects of StatinsKobashigawa et al. N. Eng. J. Med. 333(10): 621-627 (1995).• Statins reduce organ rejection and mortality aftercardiac transplant. Randomized, placebo-controlled• Statins reduce inflammation in patients withchronic rheumatoid arthritis. Randomized, placebo-controlledMcCarey et al. Lancet 363: 2015 (2004).• Statins reduce incidence of MS lesions. Smallopen-label clinical trial.Vollmer et al. Lancet 363: 1607 (2004).• Statins reduce proteinuria in sytemic lupuserythematosus. Small open-label clinical trial.Abud-Mondoza et al. Lupus 12: 607 (2003).Multiple Sclerosis• Effects up to one million worldwide• 16,000 deaths in 2002 (0.03 %)• Autoimmune attack of myelin in brain and spinalcord• Progressive physical disability• Current therapies include injected Ifn-β andcopaxone (basic peptides)Lesions on cerebellum and spinal cord ofan MS patient; Jean Cruvelhier circa 1860• Statins reverse disease pathology in the EAE mousemodel of MS!Youssef S, Stuve O, Patarroyo JC, Ruiz PJ, Radosevich JL, Hur EM, Bravo M,Mitchell DJ, Sobel RA, Steinman L, Zamvil SS. “The HMG-CoA reductaseinhibitor, atorvastatin, promotes a Th2 bias and reverses paralysis incentral nervous system autoimmune disease.” Nature 420: 78-84(2002).Immune System OverviewInate AdaptiveNK cellsAPC B cells T cellsprofessionalIfn-γinducedγδCD4helperCD8cytotoxicTH1 TH2IL2Ifn-γTNFαIL4, 10TGFβIfn-βIL12 from activatedmacrophages anddendritic cells+Tc/MHC1/CD8 versus Th/MHC2/CD4The MHC MoleculesClass I Class IIMHC Antigen PresentationExpressed in ALLCELLSExpressed inPROFESSIONAL APCINF-γ can induceexpression in non-APCduring acute immuneresponse; this is also ahallmark of auto-immunediseasesTh1 vs. Th2 Helper Cellsextracellular pathogense.g. helminthsalso oral antigensLFA-1 !Th1 vs. Th2 AntagonismSTATINS ALTER THIS BALANCE IN FAVOR OF TH2 HELPER CELLS.BUT HOW?Isoprenoids in Humans1. Steroids Hormones2. Metabolites (Vit. A, E, K; co-Q; 25,000 terpenoids)3. Isopentyl adenosine (tRNA)4. Dolichol (N-linked glycosylation)5. Protein PrenylationIsoprenoids in G Protein SignalingHeterotrimeric (GPCR’s)“Small” (RTK’s)Statin influences on prenylation of singaling molecules willlikely be "chemocopied" by a new class of drugs, thesmall-molecule prenylation inhibitors.Statins Bind to LFA-1 DirectlyLymphocyte Function Associated Antigen is an