Progressive nigrostriatal terminal dysfunction and degeneration in the engrailed1 heterozygous mouse model of Parkinson's disease.

Current research on Parkinson's disease (PD) pathogenesis requires relevant animal models that mimic the gradual and progressive development of neuronal dysfunction and degeneration that characterizes the disease. Polymorphisms in engrailed 1 (En1), a homeobox transcription factor that is crucial for both the development and survival of mesencephalic dopaminergic neurons, are associated with sporadic PD. This suggests that En1 mutant mice might be a promising candidate PD model. Indeed, a mouse that lacks one En1 allele exhibits decreased mitochondrial complex I activity and progressive midbrain dopamine neuron degeneration in adulthood, both features associated with PD. We aimed to further characterize the disease-like phenotype of these En1(+/-) mice with a focus on early neurodegenerative changes that can be utilized to score efficacy of future disease modifying studies. We observed early terminal defects in the dopaminergic nigrostriatal pathway in En1(+/-) mice. Several weeks before a significant loss of dopaminergic neurons in the substantia nigra could be detected, we found that striatal terminals expressing high levels of dopaminergic neuron markers TH, VMAT2, and DAT were dystrophic and swollen. Using transmission electron microscopy, we identified electron dense bodies consistent with abnormal autophagic vacuoles in these terminal swellings. In line with these findings, we detected an up-regulation of the mTOR pathway, concurrent with a downregulation of the autophagic marker LC3B, in ventral midbrain and nigral dopaminergic neurons of the En1(+/-) mice. This supports the notion that autophagic protein degradation is reduced in the absence of one En1 allele. We imaged the nigrostriatal pathway using the CLARITY technique and observed many fragmented axons in the medial forebrain bundle of the En1(+/-) mice, consistent with axonal maintenance failure. Using in vivo electrochemistry, we found that nigrostriatal terminals in the dorsal striatum were severely deficient in dopamine release and reuptake. Our findings support a progressive retrograde degeneration of En1(+/-) nigrostriatal neurons, akin to what is suggested to occur in PD. We suggest that using the En1(+/-) mice as a model will provide further key insights into PD pathogenesis, and propose that axon terminal integrity and function can be utilized to estimate dopaminergic neuron health and efficacy of experimental PD therapies.

A proprietary black cumin oil extract (Nigella sativa) (BlaQmax®) modulates stress-sleep-immunity axis safely: Randomized double-blind placebo-controlled study.

Objective: Stress, sleep, and immunity are important interdependent factors that play critical roles in the maintenance of health. It has been established that stress can affect sleep, and the quality and duration of sleep significantly impact immunity. However, single drugs capable of targeting these factors are limited because of their multi-targeting mechanisms. The present study investigated the influence of a proprietary thymoquinone-rich black cumin oil extract (BCO-5) in modulating stress, sleep, and immunity. Methods: A randomized double-blinded placebo-controlled study was carried out on healthy volunteers with self-reported non-refreshing sleep issues (n = 72), followed by supplementation with BCO-5/placebo at 200 mg/day for 90 days. Validated questionnaires, PSQI and PSS, were employed for monitoring sleep and stress respectively, along with the measurement of cortisol and melatonin levels. Immunity markers were analyzed at the end of the study. Results: In the BCO-5 group, 70% of the participants reported satisfaction with their sleep pattern on day 7 and 79% on day 14. Additionally, both inter- and intra- group analyses of the total PSQI scores and component scores (sleep latency, duration, efficiency, quality, and daytime dysfunction) on days 45 and 90 showed the effectiveness of BCO-5 in the improvement of sleep (p < 0.05). PSS-14 analysis revealed a significant reduction in stress, upon both intra (p < 0.001) and inter-group (p < 0.001) comparisons. The observed reduction in stress among the BCO-5 group, with respect to the placebo, was significant with an effect size of 1.19 by the end of the study (p < 0.001). A significant correlation was also observed between improved sleep and reduced stress as evident from PSQI and PSS. Furthermore, there was a significant modulation in melatonin, cortisol, and orexin levels. Hematological/immunological parameters further revealed the immunomodulatory effects of BCO-5. Conclusion: BCO-5 significantly modulated the stress-sleep-immunity axis with no side effects and restored restful sleep.