SUMMARY
# MLCS Quantification in Parkinson's Disease
## Background and Rationale
Mitochondria-lysosome contact sites (MLCS) represent a critical and relatively recently discovered cellular interface that orchestrates fundamental neuronal homeostatic processes essential for neuronal survival and function. These dynamic membrane contact sites, which constitute approximately 5-20% of the mitochondrial surface in healthy neurons, serve as platforms for coordinating mitochondrial quality control, lipid metab
METHODOLOGY NOTES
**Phase 1: iPSC Derivation and Dopaminergic Neuronal Differentiation**
Obtain CD34+ hematopoietic stem cells or fibroblasts from 5 Parkinson's Disease patients (mean age 60±8 years, Hoehn-Yahr stage 2-3, confirmed diagnosis) and 3 age-matched healthy controls. Reprogram to iPSCs using Sendai virus-based delivery of OCT4, SOX2, KLF4, and c-MYC. Maintain iPSC colonies in mTeSR Plus medium on Matrigel-coated dishes. Perform karyotyping and pluripotency validation via immunofluorescence (OCT4, NANOG, SOX2) and flow cytometry. Differentiate iPSCs to midbrain dopaminergic neurons following established dual-SMAD inhibition protocol: Day 0-3, culture in neural induction medium containing LDN193189 and SB431542; Day 3-10, add FGF8, CHIR99021, and purmorphamine; Day 10-25, supplement with GDNF, BDNF, and cAMP. Achieve ≥65% TUJ1+/MAP2+/TH+ dopaminergic neurons by Day 25 (assessed via high-content screening of ≥10,000 cells per line). Mature neurons for additional 10 days on poly-D-lysine/laminin-