Quantitative BM Criteria, 20220119 / 20220130 Drafts, And Target Validation Plan

→ 3,888 subjects

1. ROPAD study – 0.8% PRKN mutation carriers (biallelic and monoallelic) out of 13,000 PD subjects genotyped (any age of onset)
2. About 700 Parkin and PINK1 patients from 89 centers identified through the MJFF Parkin/PINK1 effort (biallelic and monoallelic), of whom 2/3 can be re-contacted.

Quantitave BM criteria:

		Dysregulation in patients	Needed change
기술		will be informed by animal study, natual Hx study	a quantitative relationship between the change of the biomarkers and treatment response will be modelled using a rat disease model in combination with 6-OHDA, MPTP treatment). (is there a linear correlation? What's the degree of correlation? Is there a threshold?)
CSF Parkin protein		To be verified (cf? brain ↓ 70% )	(GT : ↑ X1)
Ps65-ub		↓ 100% (to be verified)
MC1		? to be verified, (cf ↓ 30% MC1 activity).
Datscan	No need to mention

For clinical trials with ‘PD patients with PRKN mono-allelic mutation’ and ‘PD patients with low Parkin protein levels’, the same biomarkers that are currently in development for ‘PD patients with PRKN bi-allelic mutation’ will be used: transgene expression (CSF Parkin protein), pharmacodynamic effect (CSF ps65-ub) and disease progression (DaTSCAN).

20220119 기술본: To develop a biomarker that can be used for selecting PD patients with low Parkin protein levels, the team will establish a correlation of the level of the key biomarkers (eg. Parkin protein and ps65-ub) between the target brain regions (ie nigrostriatum), CSF and plasma using postmortem samples of PD patients. In order to define the biomarker quantitative targets, a quantitative relationship of the treatment-induced changes in the biomarkers and DA neurodegeneration will be modelled using a rat disease model. If a novel Parkin PET tracer is successfully developed, it can be used for the patient selection.

→ 20220130 다음처럼 바뀌었네.

Postmortem brain analysis of 12 idiopathic PD patients revealed soluble Parkin protein reduction by ~50% in the striatum⁷. PRKN gene overexpression can reduce α-syn-induced neurotoxicity in vitro⁸ and in vivo^9,10, therefore PRKN gene therapy would have the potential to benefit to most PD patients, about 60,000,000 worldwide. To identify PD patients with reduced Parkin protein a biomarker to detect Parkin protein levels needs to be established, e.g., using the correlation of key biomarkers (e.g., Parkin protein and ps65-ub) between the target brain regions, CSF, and plasma using postmortem samples of PD patients. If a novel Parkin PET tracer is successfully developed, such could be used for patient selection.

The normal reference value of the CSF (and plasma) Parkin protein level will be determined by conducting a cross-sectional observational reference cohort study in healthy individuals. If a novel Parkin PET tracer is successfully developed, it can used for the patient selection.

Target validation / Postmortem plan

Row	Target validation Literature evidence	Human data	Preclinical evidence	TM
Heterozygous PRKN-PD	Risk factor analysis (already data available), because OR is small, we need strong rationale for causality,	(postmortem) 아래 필요한가? Relationship 필요: heterozygousity - mt function - DA	Biological study plan (preclinical evidence) 필요함.	Patient selection: no BM needed, Rewriting: i) heteroz 군에서 parkin level 재겠다.
Idiopathic PD patients with reduced parkin protein level	{Lonskaya, 2013 #1742} Georgetown University phospho-parkin was probed (1:1000) with anti-Ser 378 antibodies (PierceParkin), which was not detected in the soluble fraction, was observed in the insoluble extract ..)( not in cortex), SN은 안 본 듯 *flow: ↑ several kinase activity (eg casein kinase 1, protein kinase A, protein kinase C, cyclin-dependent kinase 5, c-Abelson (Abl), PINK1) or ↑ aSyn → ↑ phosphorylatin → ↓ solubility → ↓ enzymatic activity → ↓ mitophagy TV: d=1.87. 정리하면, sPD patients 중, average individual in control group 보다 i) 조금이라도 감소자는 97%, ii) 50%이상 감소자는 36%.	(postmortem) i) Disease impact: PD patients have less Parkin protein? (ie 군간차이), need n=8 each ii) Phenotype impact: relationship between parkin protein level - mt function iii) (frequency) Proportion of 36%: need n=38	Biologial study plan (preclinical evidence) 필요함. → 근데 Takeshi 는 아무것도 안 하겠지.	BM for PS 가 중요 i) Parkin PET: best ii) CSF Parkin (근데 CSF 는 screening용으로 못 쓰잖아): correlation with brain parkin 필요한데, chance unknown (뇌 전반적으로 parkin protein 줄었다면 고가능성, or SN 만 줄었다면 저가능성), 이거 plan flow: CSF parkin protein assay establishment → postmortem brain tissue (including cortex and SN) & postmortem CSF iii) Peripheral parkin: ?   - Plasma?   - PBMC? Postmorte blood 에서 추출 불가능할 것.   - Skin? 근데 brain level 과 correlation 못 하자냥?   - muscle? 근데 brain level 과 correlation 못 하자냥?

[plan] i) to establish a correlation of the Parkin protein level between in the target brain region (ie NS) and plasma using PM samples from PD patients. ii) The normal reference value of the plasma parkin protein level will be determined by conducting a cross-sectional observational reference cohort study in healthy individuals. If a novel Parkin PET tracer is successfully developed, it may be used for the patient selection.

→ 8 명이면 이것을 test 할 수 있다. → this data doesn’t help → we need a study. (then sse?) → (사전정보가 없가 없을 때) Proportion 에 대한 sample size 방법?,

제출기술: Postmortem brain analysis of 12 idiopathic PD patients revealed soluble Parkin protein reduction by ~50% in the striatum in ~36% PD patients compared to control⁸. As the sample number published is low, the team is considering analyzing additional samples to reach effect size. A study using postmortem PD brains would require a sample size of 38 for estimating the expected proportion (36%) with 10% margin of error and 80% confidence.

i) 이 proportion 이 맞는지는 38명 필요, ii) 군간차이 확인은 8+8명 필요.

에 GE 가 설자리가 없네?

Questions / Needs / criteria / timeline

Questions/Needs	How to address	criteria	timeline
- Disease impact: PD patients have less Parkin protein? (ie 군간차이), need n=8 each	PM Brains: 5 sPD SNs and 5 HC SNs → this is pilot and can inform effect size, if we see a sign then we may increase n.	- Group difference of brain Parkin protein level (between sPD and HC) d>0.65 -군전체를 대상으로 임상할게 아니니까 큰 group differnce 가 필요한 게 아니지. 어차피 subgroup 이 필요한 거니까. 대신 statistically significant difference 필요?	-
- Phenotype impact: relationship between parkin protein level – mt function		- Correlation coefficient between brain parkin protein level and brain mitochondrial function (? r>0.6	-
다음은 n 부족으로 못함. (frequency) Proportion of 36%: need n=38		다음으로 충당되나? Correlation of parkin protein level between brain and plasma → if r is very large, it should, but if not, it shoundlt,
a correlation of the Parkin protein level between in the target brain region (ie NS) and plasma	PM brain and plasma from PD patients and HC: 11 SNs and 11 matched plasma (1 parkin-PD, 5 sPD, 5 HC) → this is pilot and can inform effect size, if we see a sign then we may increase n.	Correlation coefficient of parkin protein level between brain and plasma: r>0.6
The normal reference value of the plasma parkin protein level	a cross-sectional observational reference cohort study in healthy individuals.