Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by CAG repeat expansion in the HTT gene. Existing toxin-induced and genetic models provide important insights, but none fully replicate the progressive pathology of HD. An AAV9-mediated striatal mouse model expressing mutant HTT with 82 CAG repeats was established to reproduce hallmark neuropathological changes and behavioral deficits. Male C57BL/6 mice received bilateral intrastriatal injections of AAV9-HTT-82Q or control AAV9-GFP. Behavioral performance was assessed by rotarod, balance beam, open field, and Y-maze tests. Neuropathology was examined with HE/Nissl staining, TUNEL assay, and immunofluorescence for mHTT, DARPP-32, GFAP, and Iba1. AAV9-82Q mice exhibited progressive motor coordination deficits on the rotarod from Week 4 and impaired beam traversal from Week 18. Open field testing revealed persistent hyperactivity from Week 8, while anxiety-like and cognitive measures showed only mild, non-significant trends. Histological analysis demonstrated extensive mHTT aggregation in the striatum, accompanied by neuronal pyknosis, vacuolization, and significant loss of Nissl-positive neurons. TUNEL staining confirmed increased apoptosis. Immunofluorescence further revealed selective reduction of DARPP-32+ medium spiny neurons, along with marked astrogliosis and microgliosis, indicating robust neurodegeneration and inflammatory responses. The AAV9-82Q model induces adult-onset, progressive HD-like pathology with early motor impairments, neuronal loss, and glial activation. It complements existing models and provides a reproducible platform for mechanistic studies and preclinical therapeutic evaluation.

Huntington's Disease (HD) is a neurodegenerative ailment characterized by progressive motor, cognitive, and psychiatric decline, linked with mitochondrial dysfunction, oxidative stress, and neuroinflammation. Few effective treatments are available for Huntington's. Additionally, the therapeutic effects of natural polysaccharides against neurodegenerative disorders have not yet been fully explored. This study aimed to investigate the neuroprotective potential of Aloe Polysaccharides (APs) against 3-Nitropropionic Acid (3- NPA)-initiated HD-like symptoms in rats. Adult male rats were allocated to control, 3-NPA-treated, and APs-treated groups (100 and 200 mg/kg orally) following 3-NPA administration. Behavioral assessments (rotarod, open field, narrow beam walking) and biochemical analyses, including neurotransmitters [Acetylcholinesterase (AChE), Acetylcholine (ACh), Dopamine (DA), Norepinephrine (NE), Serotonin (5-HT), Gamma-Aminobutyric Acid (GABA), Glutamate (Glu)], oxidative/nitrative stress markers [Malondialdehyde (MDA, Nitric Oxide (NO)], antioxidant enzymes [Superoxide Dismutase (SOD), Catalase (CAT), Glutathione (GSH)], mitochondrial enzyme [Succinate Dehydrogenase (SDH)], inflammatory mediators [Nuclear Factor Kappa B (NF-κB), Tumor Necrosis Factor Alpha (TNF-α), Interleukin- 1 Beta (IL-1β), Cyclooxygenase-2 (COX-2)], neurotrophic factor [Brain-Derived Neurotrophic Factor (BDNF)], and apoptotic markers (caspase-3, caspase-9, B-Cell Lymphoma 2 (Bcl-2), Bcl-2-Associated X Protein (Bax)] were performed. Additionally, the impact of APs on regulators of mitochondrial biogenesis and antioxidant response [Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2), Sirtuin 1 (Sirt1), Heme Oxygenase-1 (HO-1), NAD(P)H Quinone Dehydrogenase 1 (NQO1), Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-Alpha (PGC-1α), Adenosine Monophosphate-Activated Protein Kinase (AMPK), Uncoupling Protein 1 (UCP1), Uncoupling Protein 2 (UCP2)] was evaluated. Histopathological examination of the striatum was conducted. Statistical analysis was performed using one-way ANOVA followed by Tukey's post hoc test. 3-NPA administration induced significant motor deficits, neurotransmitter imbalance, elevated oxidative stress, inflammation, mitochondrial impairment, BDNF depletion, apoptosis, and striatal degeneration (P < 0.01). APs treatment significantly (P < 0.01; P < 0.001) reversed 3-NPA effects and improved behavioral performance (rotarod latency, OFT exploratory activity, and beam walk score); restored neurotransmitter balance; improved antioxidant enzymes (SOD, CAT, and GSH); mitigated MDA and NO effects; suppressed NF-κB, TNF-α, IL-1β, and COX-2; elevated BDNF and SDH activities; mitigated apoptosis (caspase-3 and 9, BAX, and BCl-2); and preserved striatal structure. APs showed neuroprotective potential in 3-NPA-induced HD rats by modulating the BDNF/NF-κB/Nrf2 pathway, controlling oxidative stress and neuroinflammation, restoring neurotransmitter function, and arresting striatal damage. Treatment with Aps markedly upregulated the levels of mitochondrial biogenesis-related proteins (Sirt1, PGC-1α, AMPK, UCP1, and UCP2) and antioxidant defense mediators (HO-1 and NQO1). In addition to behavioral and biochemical improvements, this study uniquely demonstrates that APs upregulate genes central to the mitochondrial biogenesis pathway, suggesting a new mechanistic basis for their neuroprotective effects in 3-NPA-induced HD. The study results showed that Applied Physiology Solution (APS) enhanced behavioural characteristics and neurotransmission function while simultaneously reducing the inflammatory response and cell stress and preserving striatal tissue structure. These findings reveal that APs promote neuroprotection not only by modulating oxidative stress, neuroinflammation, neurotransmission, and apoptosis, but also by specifically upregulating genes in the mitochondrial biogenesis pathway, highlighting their potential as a natural therapeutic candidate for HD management.

Huntington’s disease (HD) pathogenesis involves diverse cellular mechanisms, yet the contributions of pyroptosis and ferroptosis remain elusive. Roflumilast, a phosphodiesterase-4 (PDE-4) inhibitor, has shown neuroprotective effects, but its precise mechanisms are yet to be elucidated. We evaluated the potential neuroprotective and therapeutic effects of roflumilast in 3-nitropropionic acid (3-NP)-induced HD-like neurodegeneration, focusing on pyroptotic and ferroptotic cell death signaling. Adult male Wistar rats were assigned to five groups: normal control (saline + 0.5% carboxymethyl cellulose), roflumilast-control (1 mg/kg/day, p.o. for 21 days), 3-NP (20 mg/kg/day, i.p. for seven days), roflumilast-prophylactic (1 mg/kg/day, p.o. for 21 days prior to 3-NP), and roflumilast-treatment (1 mg/kg/day, p.o. for 21 days post-3-NP). Behavioral outcomes of the open-field, rotarod, and grip strength tests were assessed. Striatal PDE-4, total and p-CREB, BDNF, interleukin-1β, and markers of pyroptosis (NLRP3, caspase-1, and gasdermin D) and ferroptosis (iron, GPx4, GSH, and malondialdehyde) were measured alongside histopathological alterations and GFAP and Iba-1 immunohistochemical staining. Bioinformatics was used to visualize the target genes’ protein-protein interaction network. Behavioral assessments revealed impaired locomotion, motor coordination, and muscle strength in the 3-NP-injected rats. Biochemical analysis showed increased striatal PDE-4 expression and decreased p-CREB/BDNF axis alongside NLRP3 inflammasome/caspase-1/gasdermin D activation and elevated interleukin-1β. In parallel, ferroptosis was evidenced by increased striatal iron and malondialdehyde levels, along with reduced GPx4 and GSH. Histopathological examination revealed pronounced striatal neurodegeneration, accompanied by enhanced GFAP and Iba-1 immunostaining, indicating astrogliosis and microglial activation. Roflumilast, administered prophylactically or therapeutically, significantly improved functional and behavioral abnormalities while ameliorating biochemical, histopathological, and immunohistochemical derangements induced by 3-NP. The therapeutic regimen exhibited superior efficacy relative to prophylaxis. Conclusively, roflumilast exerts therapeutic and neuroprotective effects in HD-like neurodegeneration by mitigating pyroptosis and ferroptosis, attenuating astrogliosis, microglial activation, and neuroinflammation, and restoring synaptic plasticity. A graphical abstract illustrating the proposed mechanistic pathway underlying the neuroprotection of the PDE-4 inhibitor roflumilast through reducing striatal pyroptosis, ferroptosis, microglial and astrocyte activation, and neuroinflammation, while restoring synaptic plasticity in experimental Huntington’s disease-like neurodegeneration induced by 3-NP. [Image: see text]

Huntington's Disease-like 2 (HDL2), caused by a CAG repeat expansion in JPH3, closely resembles HD. All reported HDL2 patients to date have some African ancestry. While both disorders exist in the Caribbean, their relative frequency and clinical characteristics remain largely unknown. To characterize HD and HDL2 patients in Martinique. We retrospectively analyzed all HD and HDL2 patients evaluated over 20 years at a single neurology center in Martinique, collecting longitudinal clinical features, UHDRS scores, and repeat lengths. In Martinique, combined HD and HDL2 minimum prevalence was 7.77/100,000. We ascertained 24 HD individuals, from 16 pedigrees, and 18 HDL2 individuals, from two pedigrees, one being the most extensive HDL2 pedigree yet reported. Because most HDL2 patients belong to a single large pedigree, the data must be interpreted with caution as familial clustering may introduce bias. HDL2 cases were predominantly male (83% vs. 45% in HD). Motor symptoms were the most frequent initial manifestation in both. Repeat length negatively correlated with estimated onset age in both diseases. Longitudinal motor (UHDRS-TMS) and functional capacity (UHDRS-TFC) scores in HDL2 revealed progressive worsening similar to HD. Inter- and intra-familial clinical and genetic heterogeneity was obvious in both diseases. Anticipation was not exclusively reserved to paternal transmissions in HDL2. HDL2 is nearly as prevalent as HD in Martinique. The study reinforces the similarities between HD and HDL2 in genotype-phenotype correlation and disease course, while highlighting heterogeneity and germline instability in HDL2. Interpretation is limited by the small number of HDL2 families.

Bromelain, a combination of pineapple-derived enzymes, has demonstrated neuroprotective effects owing to its antioxidant and anti-inflammatory attributes. The current study intended to explore bromelain's neuroprotective impact against 3-nitropropionic acid (3-NP)-induced Huntington's disease (HD)-like symptoms in rats. Four groups of rats were randomly allocated: group 1 received saline; bromelain (40 mg/kg/i.p.) was given to groups 2 and 4 daily, whereas groups 3 and 4 received daily doses of 3-NP (10 mg/kg/i.p.) for 14 days. On the molecular level, bromelain administration resulted in upregulation of striatal SIRT-1, PGC-1α, TFAM and Nrf2 expression, enhancement of Akt phosphorylation, elevation of FOXO3a deacetylation and lessening of striatal oxidative stress damage by lowering MDA concentrations as well as raising the levels of NQO1, TAC, SOD and GSH. These effects were further substantiated by improvements in muscle strength, locomotor coordination, cognitive performance, and neuronal integrity. In conclusion, bromelain could be a beneficial neuroprotective candidate against HD-like aberrations experimentally induced by 3-NP.