Neuroimaging, Urinary, and Plasma Biomarkers of Treatment Response in Huntington's Disease: Preclinical Evidence with the p75NTR Ligand LM11A-31

• DOI: 10.1007/s13311-021-01023-8
• Publication Date: 2021-03-30T21:02:21Z
• Authors: Danielle A. Simmons; Brian D. Mills; Robert R. Butler III; Jason Kuan; Tyne L.M. McHugh; Carolyn Akers; James Zhou; Wassim Syriani; Maged Grouban; Michael Zeineh; Frank M. Longo
• Keywords: Male; 0301 basic medicine; 2. Zero hunger; Morpholines; Drug Evaluation, Preclinical; Mice, Transgenic; Neuroimaging; Receptors, Nerve Growth Factor; 3. Good health; Mice; 03 medical and health sciences; Cross-Sectional Studies; Huntington Disease; 0302 clinical medicine; Mice, Inbred CBA; Animals; Original Article; Female; Isoleucine; Biomarkers

Huntington's disease (HD) is caused by an expansion of the CAG repeat in the huntingtin gene leading to preferential neurodegeneration of the striatum. Disease-modifying treatments are not yet available to HD patients and their development would be facilitated by translatable pharmacodynamic biomarkers. Multi-modal magnetic resonance imaging (MRI) and plasma cytokines have been suggested as disease onset/progression biomarkers, but their ability to detect treatment efficacy is understudied. This study used the R6/2 mouse model of HD to assess if structural neuroimaging and biofluid assays can detect treatment response using as a prototype the small molecule p75NTR ligand LM11A-31, shown previously to reduce HD phenotypes in these mice. LM11A-31 alleviated volume reductions in multiple brain regions, including striatum, of vehicle-treated R6/2 mice relative to wild-types (WTs), as assessed with in vivo MRI. LM11A-31 also normalized changes in diffusion tensor imaging (DTI) metrics and diminished increases in certain plasma cytokine levels, including tumor necrosis factor-alpha and interleukin-6, in R6/2 mice. Finally, R6/2-vehicle mice had increased urinary levels of the p75NTR extracellular domain (ecd), a cleavage product released with pro-apoptotic ligand binding that detects the progression of other neurodegenerative diseases; LM11A-31 reduced this increase. These results are the first to show that urinary p75NTR-ecd levels are elevated in an HD mouse model and can be used to detect therapeutic effects. These data also indicate that multi-modal MRI and plasma cytokine levels may be effective pharmacodynamic biomarkers and that using combinations of these markers would be a viable and powerful option for clinical trials.