Programmed cell death pathways in huntington's disease: spotlight on ferroptosis and pyroptosis

Huntington’s disease (HD) is characterized by dementia, delayed psychomotor processes, abnormal choreatic movements, and cognitive impairments. This condition is brought on by an increase in cytosine-adenine-guanine repeats in the huntingtin (Htt) gene on chromosome-4, which produces the Htt protein’s poly-glutamine (poly-Q). Despite significant progress in understanding the genetics of HD, the precise molecular underpinnings of selective neuronal vulnerability remain elusive, thereby limiting the development of disease-modifying therapies While apoptosis has long been considered a primary mechanism of neuronal death in HD, emerging evidence highlights the significant roles of non-apoptotic programmed cell death pathways, particularly ferroptosis and pyroptosis-in driving HD progression. Ferroptosis is form of cell death that is dependent on iron and driven by lipid peroxidation, appears to be associated with HD. On the other hand, Pyroptosis, a caspase-1-dependent inflammatory cell death pathway mediated by activation of inflammasome and release of pro-inflammatory cytokines such as interleukin-1β and IL-18. Both pathways contribute to the neurodegeneration in HD through distinct yet interconnected pathways. Therefore, this review highlights molecular mechanisms underlying ferroptosis and pyroptosis in HD and recent advances in pharmacological strategies targeting these pathways.