Background <p>Huntington’s disease (HD) is an inherited, fatal neurodegenerative disorder caused by expanded CAG repeats in the Huntingtin gene, leading to progressive motor, cognitive and psychiatric impairment. Despite its monogenic origin, HD pathogenesis is multifactorial, with convergent contributions from mitochondrial dysfunction, oxidative stress, synaptic failure, and chronic neuroinflammation, which drive neuronal vulnerability and degeneration, particularly within the striatum. Current clinical management remains exclusively symptomatic and fails to halt disease progression, highlighting a critical unmet need for strategies targeting fundamental pathogenic mechanisms. Cortistatin, a neuropeptide expressed in the nervous and immune systems, exhibits potent immunomodulatory properties and has recently been implicated in the regulation of mitochondrial function. Notably, cortistatin deficiency is associated with exacerbated systemic and central inflammation, suggesting that impaired cortistatin signaling may contribute to neurodegeneration. However, its role in HD pathophysiology remains unexplored.</p> Methods <p>We performed a comprehensive reanalysis of publicly available transcriptomic datasets from HD patients to assess cortistatin expression, followed by validation in experimental HD models. Wild-type and cortistatin-deficient mice treated with 3-nitropropionic acid served as pharmacological HD models, enabling evaluation of cortistatin-dependent disease severity. Behavioral assessments, glial and oxidative markers, and immune factors were evaluated to determine neurological dysfunction and inflammatory responses. Complementary in vitro studies were conducted in striatal neurons expressing mutant huntingtin to examine mitochondrial integrity, inflammatory signaling, metabolic function, and mitochondria-endoplasmic reticulum interactions.</p> Results <p>Cortistatin expression was significantly reduced in postmortem HD human brains and across experimental HD models. Cortistatin deficiency exacerbated motor deficits, neuropathological alterations, inflammatory activation, and neuronal vulnerability in HD context. At the cellular level, reduced cortistatin expression was accompanied by amplified inflammatory signaling, disrupted mitochondrial integrity, impaired mitochondria-endoplasmic reticulum interactions, and increased oxidative stress. Conversely, exogenous cortistatin administration attenuated inflammatory mediator production, preserved mitochondrial structure, and improved redox balance in mutant huntingtin-expressing striatal neurons.</p> Conclusions <p>Our findings identify cortistatin deficiency as a previously unrecognized contributor to HD pathogenesis and establish cortistatin as a key modulator of neuroinflammation and mitochondrial homeostasis. These results support cortistatin-based strategies as a promising disease-modifying therapeutic avenue for HD and related neurodegenerative disorders characterized by inflammatory activation and mitochondrial impairment.</p> Graphical Abstract <p></p>