Neuroprotective Effects of Transplanted Induced Pluripotent Stem Cell-Derived Neural Precursors in Huntington's Disease Models.

Huntington's disease (HD) is characterized by progressive striatal degeneration associated with mutant huntingtin (mHTT)-related proteostatic disruption and chronic neuroinflammation. Although mHTT-lowering approaches hold therapeutic promise, their capacity to restore the degenerating neural microenvironment remains limited. Here, we evaluated the therapeutic potential of human induced pluripotent stem cell (iPSC)-derived neural precursor cells (s513-NPCs) in two complementary HD models, the acute R6/2 transgenic fragment model and the protracted, full-length YAC128 genomic model. Intrastriatal transplantation of s513-NPCs resulted in sustained functional improvement, including stabilization of motor coordination and attenuation of neuromuscular decline, across both disease contexts. These neuroprotective effects were accompanied by efficient donor cell engraftment and integration within the host striatum. At the molecular level, transplantation was associated with coordinated changes in proteostasis-related pathways, reflected by reduced mHTT aggregate burden and modulation of proteasomal and autophagic markers. In parallel, enhanced local BDNF-TrkB signaling was observed in grafted regions, consistent with improved neuronal support. Notably, transplanted NPCs exhibited context-dependent immunological responses, characterized by attenuation of pro-inflammatory signatures in aggressive disease stages and features of a reparative microenvironment in more protracted settings. Collectively, these findings demonstrate that iPSC-derived neural precursor transplantation confers robust neuroprotective effects in HD models, supporting its potential as a stem cell-based strategy to mitigate striatal pathology and functional decline.