M.Res Programme CRITICAL APPRAISAL Bob Lightowlers, WT Centre for Mitochondrial Research

1. M.ResProgramme CRITICAL APPRAISAL Bob Lightowlers, WT Centre for Mitochondrial Research robert.lightowlers@ncl.ac.uk

2. NOT EVERYTHING THAT IS PUBLISHED IS CORRECT!!

3. NOT EVERYTHING THAT IS PUBLISHED IS CORRECT!! ‘The statistical error that keeps on coming’ Ben Goldacre – The Guardian 9th Sept 2011

6. Problem transferring ‘effective’ drugs from mouse model to clinic • Numbers of mice not likely • to generate significance • No randomisation • No blinded evaluations • Bias in reporting • (no reporting of negative data) • Variable genetic background • Broader endpoints such as • life expectancy/behaviour • too crude Nonhuman primate models ?

7. Sept 2011 Bayer Pharmaceuticals assessed reproducibility of 67 published projects Only 20-25% of published data in line with in-house findings

8. Jan 2012 Amgen tried to confirm research from 53 published ‘landmark’ studies

9. Jan 2012 Amgen tried to confirm research from 53 published ‘landmark’ studies ONLY 6 (11%) could be confirmed

10. Jan 2012 Amgen tried to confirm research from 53 published ‘landmark’ studies ONLY 6 (11%) could be confirmed

12. What causes this lack of reproducibility ?

13. What causes this lack of reproducibility ?

14. What causes this lack of reproducibility ?

15. What causes this lack of reproducibility ?

16. What causes this lack of reproducibility ?

17. NOT EVERYTHING THAT IS PUBLISHED IS CORRECT!! ONLY 15% OF PUBLICATIONS ARE TRUSTWORTHY • Be critical • Guilty until proven innocent

18. The peer review process

19. What should we be looking for ? • Incorrect statistical analysis • Power of study • Absence of essential controls • Incorrect methodology • Over/mis interpretation of data • Lack of reference to any conflicting data

20. What should we be looking for ? • Incorrect statistical analysis • Power of study • Absence of essential controls • Incorrect methodology • Over/mis interpretation of data • Lack of reference to any conflicting data • Falsification of data

22. Somatic Cell Nuclear Transfer

24. Peer review cannot guarantee scientific integrity

25. Peer review cannot guarantee scientific integrity

26. http://www.biochem.arizona.edu/classes/bioc568/papers.htm

27. Critical Evaluation - a worked example

32. Human mtDNA • An autosomally replicating genome • Found in mitochondrial matrix • Encodes 13 proteins, all of which are • OXPHOS components 16,569 bp • Comprises app. 0.1% of total cell DNA • Varies enormously in copy number/cell • Approx. 700 in fibroblasts to >200,000 • in some mammalian oocytes • Maternally inherited • Often heteroplasmic in the diseased state

34. Hypothesis: 1. Alzheimers Disease could be caused by defects in activity of the respiratory chain complex cytochrome c oxidase 2. Alzheimers Disease is due to mutations in the mitochondrial genome

35. Why ? • Lack of FH is a negative risk factor

36. Why ? • Lack of FH is a negative risk factor • Risk of AD increases with affected maternal relative (mtDNA?)

37. Why ? • Lack of FH is a negative risk factor • Risk of AD increases with affected maternal relative (mtDNA?) • Mutations in mtDNA can lead to defective OXPHOS

38. Why ? • Lack of FH is a negative risk factor • Risk of AD increases with affected maternal relative (mtDNA?) • Mutations in mtDNA can lead to defective OXPHOS • Neurons may be particularly susceptible to such defects

39. Neurological Non-Neurological Optic Atrophy / Retinitis Pigmentosa Respiratory Failure Cardiomyopathy CVA / Seizures / Developmental delay Liver Failure Deafness Short Stature Marrow Failure Peripheral Neuropathy Diabetes Thyroid Disease Myopathy

40. Why ? • Lack of FH is a negative risk factor • Risk of AD increases with affected maternal relative (mtDNA?) • Mutations in mtDNA can lead to defective OXPHOS • Neurons may be particularly susceptible to such defects • COX activity reported to decrease in brain of AD patients

41. Methods used • MtDNA isolation and sequencing in patients, • asymptomatic relatives and controls

42. Methods used • MtDNA isolation and sequencing in patients, • asymptomatic relatives and controls • All three COX genes sequenced

43. Methods used • MtDNA isolation and sequencing in patients, • asymptomatic relatives and controls • All three COX genes sequenced • Platelet fusion from AD patients to neuronal cells • lacking mtDNA (rho0)

44. Biopsy EthBr Enucleation Generation of transmitochondrial cybrids

45. Methods used • MtDNA isolation and sequencing in patients, • asymptomatic relatives and controls • All three COX genes sequenced • Platelet fusion from AD patients to neuronal cells • lacking mtDNA (rho0) • Analysis of respiratory enzyme activity in the cybrids

46. Methods used • MtDNA isolation and sequencing in patients, • asymptomatic relatives and controls • All three COX genes sequenced • Platelet fusion from AD patients to neuronal cells • lacking mtDNA (rho0) • Analysis of respiratory enzyme activity in the cybrids • Analysis of ROS production in cybrids

47. Results 506 Patients and 95 controls

48. Results 506 Patients and 95 controls 10 clones of all three COX genes sequence

49. Results 506 Patients and 95 controls 10 clones of all three COX genes sequence 6 mutations found in COI and COII

50. Results 506 Patients and 95 controls 10 clones of all three COX genes sequence 6 mutations found in COI and COII Different levels of heteroplasmy but levels significantly greater in the AD cohort