Diagnostic and drug screening for molecular signatures of early onset sporadic parkinson's disease
Induced Pluripotent Stem Cell (Ipsc) technology enables the generation and study of living brain tissue relevant to Parkinson's disease (PD) ex vivo. Utilizing cell lines from PD patients presents a powerful discovery system that links cellular phenotypes observed in vitro with real clinical data. Differentiating patient-derived iPSCs towards a dopaminergic (DA) neural fate revealed that these cells exhibit molecular and functional properties of DA neurons in vitro that are observed to significantly degenerate in the substantia nigra of PD patients. Clinical symptoms that drive the generation of other relevant cell types may also yield novel PD-specific phenotypes in vitro that have the potential to lead to new therapeutic avenues for patients with PD. Due to their early onset and non-familial origin, differentiated nervous tissue from these patients offer a key opportunity to discover neuron subtype-specific pathological mechanisms and importantly interrogate the contribution of their genetic background in susceptibility to PD.
1 . A method of screening one or more test compounds for treating early onset sporadic Parkinson's Disease, the method comprising:
contacting a quantity of midbrain dopaminergic neurons differentiated from early onset sporadic Parkinson's Disease patient blood cell-derived induced pluripotent stem cells (iPSCs) with the one or more test compounds;
measuring a-synuclein protein levels and PKCα phosphorylation levels in the contacted midbrain dopaminergic neurons; and
selecting one or more of the test compounds as a compound or compounds for treatment of early onset sporadic Parkinson's Disease based on the measured a-synuclein protein levels and PKCα phosphorylation levels, the selected one or more compounds being able to reduce α-synuclein protein levels and PKCα phosphorylation levels in the midbrain dopaminergic neurons, compared to α-synuclein protein levels and PKCα phosphorylation levels in the dopaminergic neurons not contacted with the selected one or more compounds,
wherein the iPSCs are produced from early onset sporadic Parkinson's Disease patients who are younger than 50 years old with no reported family history of Parkinson's Disease,
wherein the midbrain dopaminergic neurons express higher levels of α-synuclein and phosphorylated PKC-α compared to controls derived from healthy subjects.
2 . The method of claim 1 , further comprising measuring at least one of transcription factor EB (TFEB) activation and zinc finger with KRAB and SCAN domains 3 (ZKSCAN3) inactivation in the contacted midbrain dopaminergic neurons.
3 . The method of claim 1 , further comprising measuring dopaminergic activities or dopamine level in the contacted midbrain dopaminergic neurons.
4 . The method of claim 1 , further comprising measuring tyrosine hydroxylase (TH) activity in the contacted midbrain dopaminergic neurons.
5 . The method of claim 1 , further comprising measuring tyrosine hydroxylase (TH) levels in the contacted midbrain dopaminergic neurons.
6 . The method of claim 1 , further comprising measuring lysosomal associated membrane protein (LAMP) 1 expression level, GCase activity, and GCase expression level in the contacted midbrain dopaminergic neurons, wherein the compound is or the compounds are selected when decreased α-synuclein protein levels, decreased PKCα phosphorylation levels, increased LAMP 1 expression level, increased GCase activity, and increased GCase expression level are detected,
wherein the midbrain dopaminergic neurons express higher levels of a-synuclein and phosphorylated PKCα and lower levels of LAMP1 expression, GCase activity, and GCase expression compared to control derived from healthy subjects.
7 . The method of claim 1 , wherein the blood cell-derived iPSCs are made by a method comprising:
contacting a quantity of blood cells with one or more oriP/EBNA1 vectors encoding a reprogramming factor;
delivering a quantity of reprogramming factors into the blood cells; and
culturing the blood cells in a reprogramming media,
wherein delivering the reprogramming factors and culturing in the reprogramming media generate blood cell-derived iPSCs.
8 . The method of claim 7 , wherein the quantity of blood cells is obtained from the early onset sporadic Parkinson's Disease patients who are younger than 50 years old with no reported family history of Parkinson's Disease.
9 . The method of claim 1 , wherein the neurons are differentiated from blood cell-derived iPSCs by a method comprising:
providing a quantity of blood cell-derived induced pluripotent stem cells (iPSCs);
culturing the iPSCs in the presence of a transforming growth factor (TGF)-beta inhibitor and an activin receptor-like kinase (ALK) inhibitor;
culturing the iPSCs in the presence of a Smoothened agonist, a RHO Kinase (ROCK) inhibitor and at least two growth factors;
culturing the iPSCs in the presence of retinoic acid; and
culturing the iPSCs in the presence of at least three additional growth factors.
10 . The method of claim 9 , wherein the transforming growth factor (TGF)-beta inhibitor comprises LDN-193189 and the activin receptor-like kinase (ALK) inhibitor comprises SB431542, the Smoothened agonist comprises Purmorphamine, the at least two growth factors comprise sonic hedgehog and fibroblast growth factor 8, the ROCK inhibitor comprises CHIR99021, and the at least three additional growth factors comprise brain derived neurotrophic factor, glial derived neurotrophic factor, and TGF-Beta 3.