Regulation of Neuronal Senescence by Srebf2 and Zmiz1 Reveals Mechanisms of Aging-Related Neurodegeneration

Neuronal senescence-like states are increasingly implicated in age-related neurodegeneration, yet the neuron-intrinsic regulators that drive these phenotypes remain poorly defined. Guided by prior transcriptomic analysis of aged basal forebrain cholinergic neurons, we investigated Srebf2 and Zmiz1 using primary basal forebrain neuronal cultures with adeno-associated virus-mediated gain- and loss-of-function, quantitative immunocytochemistry, and low-input transcriptomic profiling of fluorescence-activated cell sorting-isolated neurons. Both perturbation strategies produced the expected directional changes in target transcripts. Overexpression of either gene increased the other, whereas knockdown did not elicit reciprocal suppression, indicating asymmetric regulatory coupling. Phenotypically, Srebf2 showed a bidirectional association with senescence-like changes, as both overexpression and knockdown increased p16 and p21, whereas Zmiz1 acted more directionally, with overexpression increasing and knockdown reducing these markers. Transcriptomic profiling revealed broad direction-dependent remodeling, including a set of 55 genes that changed concordantly across perturbation directions. Pathway analysis further showed specialization, with Zmiz1 preferentially associated with an Alzheimer's disease-related signature and Srebf2 more strongly linked to cholinergic synapse programs. Together, these findings identify Srebf2 and Zmiz1 as coupled but non-equivalent regulators of a neuronal senescence-like program.