The human intestinal microbiota is a diverse and dynamic microenvironment that forms a complex, bi-directional relationship with the host. The microbiome takes part in the digestion of food and the generation of crucial nutrients such as short chain fatty acids (SCFA), but is also impacts the host’s metabolism, immune system, and even brain functions. Due to its indispensable role, microbiota has been implicated in both the maintenance of health and the pathogenesis of many diseases. Dysbiosis in the gut microbiota has already been implicated in many neurodegenerative diseases such as Parkinson’s disease (PD) and Alzheimer’s disease (AD). However, not much is known about the microbiome composition and its interactions in Huntington’s disease (HD). This dominantly heritable, incurable neurodegenerative disease is caused by the expansion of CAG trinucleotide repeats in the huntingtin gene (HTT). As a result, toxic RNA and mutant protein (mHTT), rich in polyglutamine (polyQ), accumulate particularly in the brain, leading to its impaired functions. Interestingly, recent studies indicated that mHTT is also widely expressed in the intestines and could possibly interact with the microbiota, affecting the progression of HD. Several studies have aimed so far to screen the microbiota composition in mouse models of HD and find out whether observed microbiome dysbiosis could affect the functions of the HD brain. This review summarizes ongoing research in the HD field and highlights the essential role of the intestine-brain axis in HD pathogenesis and progression. The review also puts a strong emphasis on indicating microbiome composition as a future target in the urgently needed therapy for this still incurable disease.

Huntington's disease (HD) is a neurodegenerative polyglutamine (polyQ) disease resulting from the expansion of CAG repeats located in the ORF of the huntingtin gene ( HTT ). The extent to which mutant mRNA‐driven disruptions contribute to HD pathogenesis, particularly in comparison to the dominant mechanisms related to the gain‐of‐function effects of the mutant polyQ protein, is still debatable. To evaluate this contribution in vivo, we generated two mouse models through a knock‐in strategy at the Rosa26 locus. These models expressed distinct variants of human mutant HTT cDNA fragment: a translated variant (HD/100Q model, serving as a reference) and a nontranslated variant (HD/100CAG model). The cohorts of animals were subjected to a broad spectrum of molecular, behavioral, and cognitive analysis for 21 months. Behavioral testing revealed alterations in both models, with the HD/100Q model exhibiting late disease phenotype. The rotarod, static rod, and open‐field tests showed some motor deficits in HD/100CAG and HD/100Q model mice during the light phase, while ActiMot indicated hyperkinesis during the dark phase. Both models also exhibited certain gene deregulations in the striatum that are related to disrupted pathways and phenotype alterations observed in HD. In conclusion, we provide in vivo evidence for a minor contributory role of mutant RNA in HD pathogenesis. The separated effects resulting from the presence of mutant RNA in the HD/100CAG model led to less severe but, to some extent, similar types of impairments as in the HD/100Q model. Increased anxiety was one of the most substantial effects caused by mutant HTT RNA.

Inflammation contributes to the rapid progression of high-grade gliomas, indicating that anti-inflammatory strategies targeting NF-κB signaling may offer therapeutic benefit. Cannabidiol (CBD) and celecoxib (CELE) are hydrophobic pharmacological agents whose formulation in lipid carriers may support their combined biological evaluation. In this proof-of-concept study, we investigated liposomal formulations containing CBD, CELE, or both compounds in U-87 MG high-grade glioma cells and in a subcutaneous xenograft model. We assessed cytotoxicity, apoptosis, oxidative stress, Nrf2-dependent responses, NF-κB-centered inflammatory networks, tumor cell invasive properties, and Wnt/β-catenin pathway activity. The nanoformulations induced reactive oxygen species generation by 1.8-fold, which was accompanied by Nrf2 activation. Cationic formulations loaded with the compounds produced more pronounced pro-apoptotic effects (up to 39%) than POPC liposomes, although both types reduced the nuclear translocation of the NF-κB p65 subunit. The CBD + CELE-containing formulation showed a trend toward reduced tumor progression in mice. It is important to note that the in vitro and in vivo nanoformulations were physicochemically related, but not identical, and the in vivo experiment should be interpreted as a preliminary assessment after intratumoral administration. Overall, cationic liposomes co-loaded with CBD + CELE represent a promising platform for further optimization aimed at coordinated modulation of inflammatory, oxidative, and proliferative pathways in glioma. However, additional studies, including tissue distribution, release kinetics, and efficacy in orthotopic glioma models, are needed to fully verify their translational potential.