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HAPLOGROUP COMPATIBILITY AND HOW mtDNA CAN INFLUENCE TRAITS BEYOND DISEASE Doug Wallace Center for Mitochondrial and Epigenomic Medicine Children’s Hospital of Philadelphia THE mtDNA CONTROLS THE MITOCHONDRIAL POWER PLANT CAPACITOR AND THUS IS THE POWER PLANT WIRING DIAGRAM: IT IS NOT TRIVIAL Tissue Specific Manifestations: Brain: Continuous energy demand. 2% body weight but consumes 20% oxygen. Heart>Muscle>Renal>Endocrine>Intestinal: Episodic energy demand. THE mtDNA CAN HARBOR BOTH DISEASE CAUSING AND BENEFICIAL VARIANTS THE MITOCHONDRIAL GENOME: ~ 1500 Dispersed nDNA Genes 37 mtDNA Genes High Mutation Rate (ROS-Repair-etc.) THREE CLASSES OF mtDNA VARIANTS Ancient Functional Polymorphisms Recent Deleterious Mutations Somatic Mutations HUMAN mtDNA CHANGED AS OUR ANCESTORS MIGRATED OUT-OF-AFRICA PERMITTING THEM TO ADAPT TO DIFFERENT ENVIRONMENTS from http://www.mitomap.org Mutation rate = 2.2 – 2.9% / MYR Time estimates are YBP ANCIENT mtDNA VARIANTS CAN BE BOTH GOOD AND BAD DEPENDING ON CONTEXT EUROPEAN tRNAGln 4336A>G VARIANT BECAME ESTABLISHED BUT NOW REDISPOSES TO ALZHEIMER & PARKINSON DISEASE Haplogroup H5a: Ancient polymorphism AD = 3.3%, PD = 5.3%, AD+PD = 6.8%, CNTL = 0.4% ASSOCIATIONS BETWEEN mtDNA HAPLOGROUPS & HUMAN TRAITS H > J = T > U (Uother > U4 = U5a1 > Uk). • NEURODEGENERATIVE DISEASES – – – – – • Alzheimer Disease Parkinson Disease Macular Degeneration Migraine Psychiatric Disorders NEUROLOGICAL DISEASES – Stoke • METABOLIC DISEASES – Diabetes – Cardiovascular Disease – Metabolic Syndrome • INFLAMMATORY & INFECTIOUS DISEASES – – – – – – • • • Sepsis IgE Levels Asthma AIDS progression Anti-AIDS HAAT* Lipodystrophy Osteoarthritis AGING CANCERS ATHLETIC PERFORMANCE (L0>L3>N>H>J-U-T) * HAAT- highly active anti-retroviral therapy CYTOPLAMIC MIXING TO INCREASE FERTILITY OF INFERTILE EGGS HAS CREATED HETEROPLASMY Father ♂ Sperm Recipient oocyte Egg ♀ ICSI Donor oocyte Ooplasmic Transfer Heteroplasmic zygote Infertile Mother Heteroplasmic child Unrelated Younger Donor Differentiated cell Barritt JA, Brenner CA, Malter HE, & Cohen J. Mitochondria in human offspring from ooplasmic transplantation. Human Reproduction 16: 513-516 (2001). HETEROPLASMY BETWEEN mtDNA HAPLOGROUPS CAN CAUSE NEUROPSYCHIATRIC DISEASES AND LEARNING PROBLEMS HETEROPLASMY OF TWO “NORMAL” (NZB+129) mtDNAs IS ELIMINATED LM(TK-) (mtDNA NZB) Disaggregate 129 Agouti Mice 129 ES Cell Cells Rhodamine 6G Female ES Cybrids (Heterplasmic NZB129 mtDNA) Backcross 129 nDNA (NZB + 129 mtDNAs) females to B6 males > 9 generations Female Chimera Pseudopregnant mother MIXING TWO NORMAL MOUSE mtDNAs (NZB + 129) CAUSES NEUROPSYCOLOGICAL PHENOTYPES CREATION OF NZB-129 HETEROPLASMIC MICE BamH A4276G M NW 91 “129” vs “NZB” mtDNAs differences: 15 aaΔ +5 tRNA +7 rRNA + 11 CR 0 I 2000 I II I 4000 II I III II I II III I I 6000 I II III I I I II 8000 I I II III 10000 I I II I II IIIII I IIII 12000 II I 14000 16000 III I II I I I I IIIIII I II I IIII II I I III Backcrossed 20 generations onto C57BL/6L nDNA. Permitted nZB-129 mtDNAs to segregate. Correlated mtDNA NZB-129 genotypes with behavior. GENERTATION FROM THE HETEROPLASMIC MICE OF HOMOPLASMIC DERIVATIVES TO ASSESS THE DIFFERENTIAL EFFECTS OF THE HETEROPLASMIC MIXING NZB-129 HETEROPLASMIC MICE EXHIBIT DIMINISHED ACTIVITY, FOOD CONSUMPTION, & METABOLIC RATE BUT HEIGHTEN RESPONSE TO STRESS REDUCED COGNITIVE CAPACITY OF NZB-129 HETEROPLASMIC MICE SIMPLY TRANSFERRING mtDNAs FROM ONE NUCLEUS TO ANOTHER HAS MAJOR EFFECTS ON LEARNING AND BEHAVIOR a) Radial Maze: 3 months. b) Krushinsky Test: 3 months. c) Morris Hidden Platform Water Maze: 3, 6, 12 months. d) Probe Test-No Platform: 3 months. Mitochondrial DNA modifies cognition in interaction with nuclear genome and age in mice. Roubertoux PL et al. (2003) Nature Genetics 35:65-69 H H N N mtH mtN SUGGESTIONS RELATING TO mtDNA HAPLOGROUPS Apply spindle transfer only to women with severe mtDNA mutations, preferably with previous reproductive failure. -Cost-Benefit Ratio justified. -Negative outcome for child otherwise assured. Avoid heteroplasmy. Use haplogroup matched mtDNA donors. - For heteroplasmic women, preferably use female donor on maternal lineage prior to occurrence of mutant mtDNA. -When maternal relatives not available use haplogroup matched donor. Prohibit for now the use of spindle transfer to treat advanced maternal age infertility. -Cost-Benefit Ratio not justified. -Possible long-term risk to society too great if spindle transferred proves deleterious and used for thousands of children. A MITOCHONDRIAL ETIOLOGY OF COMPLEX DISEASE Environmental Factors Energy Sources Carbohydrates, Fats, Amino Acids Energy Uses Growth, Maintenance, Reproduction Toxins Metabolic Type II Diabetes, Obesity Hypertension, CVD Stress Thermal, Trauma mtDNA Variants Ancient Adaptive Polymorphisms Recent Deleterious Mutations OXPHOS DYSFUNCTION ↓ENERGY,↑ ROS, Δ REBOX, Δ Ca++ mtDNA Damage & Somatic Mutations PROGRESSIVE BIOENERGETIC DECLINE Apoptosis Inflammation, Immunity MS, Type I Diabetes (DAMPs) Infection Predisposition Sepsis, AIDS (Zhang Q et al, 2010, Nature 464:104) Aging Penetrance & Expressivity Delayed-Onset & Progression, nDNA Variation Mutations Deleterious Mutations, Mito Gene Polymorphisms Epigenomics Histone Modifications, Signal Transduction, Redox Controls Neuropsychological Blindness, Deafness AD, PD, Depression Muscle Myalgia, Fatigability Cardiomyopathy Renal Failure Cancer Energy Production, ROS & Redox