Ass. Prof. Johannes Kepler University Linz / Medical Faculty Linz, Oberosterreich, Austria
Abstract: Parkinson’s disease is a neurodegenerative disorder characterized by a progressive loss of midbrain dopaminergic neurons (mDAn). Aging, among others, is considered as a potential degenerative factor. It has been shown that progerin, a truncated form of Lamin A, accelerates cellular aging and is implicated in pathological conditions like Hutchinson-Gilford Progeria Syndrome. This study investigates the impact of progerin overexpression on mDAn derived from human-induced pluripotent stem cells (hiPSCs), focusing on aging hallmarks and neurodegenerative phenotypes. An inducible Tet-ON GFP-T2A-progerin construct was used to overexpress progerin in hiPSC-derived mDAn alongside an isogenic control. Neurons were treated with doxycycline (DOX) during the maturation phase. Immunofluorescence (IF) was employed to assess markers of cellular aging (H3K9me3, HP1γ, γH2AX, p53BP1) and neurodegeneration (TH, α-synuclein). Quantifications were performed using fluorescence microscopy. The proportion of TH+ and α-synuclein+ cells was analyzed alongside DNA damage foci and chromatin remodeling markers. Progerin overexpression induced significant aging hallmarks at day 30 of differentiation, with an increased levels of H3K9me3 and HP1γ (p < 0.05) and elevated DNA damage foci as indicated by γH2AX and p53BP1 (p < 0.01). Neurodegenerative phenotypes were evident, with a reduction in TH+ neurons (p < 0.001) and an increase in α-synuclein+ cells (p < 0.0001). The proportion of α-synuclein+ cells within the TH+ population also increased significantly (p < 0.0001). Notably, the GFP+ DOX - induced mDAn (TH+) revealed to be the ones with increased levels of α-synuclein, thus correlating progerin overexpression with neurodegeneration. These results highlight the dual impact of progerin on aging and neurodegeneration. This model provides a robust in vitro platform to study the interplay between aging and neurodegeneration, offering valuable insights into the mechanisms underlying Parkinson’s disease and related disorders. Furthermore, it serves as a promising tool for identifying and testing potential therapeutic interventions targeting age-related neuronal dysfunction.
