Dunalialla salina microalgea and its isolated zeaxanthin mitigate age-related dementia in rats: Modulation of neurotransmission and amyloid-β protein

Ameliorative effects of Dunaliella salina microalgae on nanoparticle (ZnO NPs)-induced toxicity in fish

Dunaliella salina (D. salina) is a well-known microalga that contains considerable amounts of nutritious and medicinal bioactive components. This work studied the modulatory role of D. salina against zinc oxide nanoparticle (ZnO NPs)-induced neurotoxic effects in adult zebrafish. Fishes were subjected to 0.69 mg L-1 (1/5th 96-h LC50) for 4 weeks; then, fishes were supplemented with D. salina in the diet for 2 weeks at two levels (15 and 30%). Exposure to ZnO NPs induced a significant increase in the levels of reactive oxygen species (ROS), hydrogen peroxide (H2O2), malondialdehyde (MDA), and 8-hydroxy-2-deoxyguanosine (8-OH-dG) while accompanied with downregulation of antioxidant genes in the brain of exposed fishes. Brain neurochemistry and enzyme activities were also altered following ZnO NP exposure. ZnO NPs significantly reduced the neurotransmitters and acetylcholinesterase (AchE) activity while increasing Alzheimer's disease-related proteins and inflammatory response via upregulation of tumor necrosis factor (TNF-α). Additionally, ZnO NPs increased the indices of brain's DNA oxidative damage, increasing brain tissue's metallothionein (MT) and zinc residues. ZnO NPs upregulated the transcription patterns of apoptosis-related genes (casp3 and p53). D. salina dietary co-supplementation with ZnO NPs alleviated the ZnO NPsZnO NP-induced neuro-oxidative damages by lowering the lipid, DNA damage, and inflammatory biomarkers. Besides, D. salina alleviating responses were linked with increasing the levels of the assessed antioxidants. Conclusively, D. salina dietary supplementation induced potential alleviating effects of the ZnO NP-induced neurotoxicity in adult zebrafish.

Metabolic Engineering of Yarrowia lipolytica for Zeaxanthin Production

Zeaxanthin is a carotenoid, a dihydroxy derivative of β-carotene. Zeaxanthin has antioxidant, anti-inflammatory, anticancer, and neuroprotective properties. In this study, Yarrowia lipolytica was used as a host for the efficient production of zeaxanthin. The strain Y. lipolytica PO1h was used to construct the following engineered strains for carotenoid production since it produced the highest β-carotene among the Y. lipolytica PO1h- and Y. lipolytica PEX17-HA-derived strains. By regulating the key nodes on the carotenoid pathway through wild and mutant enzyme comparison and successive modular assembly, the β-carotene concentration was improved from 19.9 to 422.0 mg/L. To provide more precursor mevalonate, heterologous genes mvaE and mvaSMT were introduced to increase the production of β-carotene by 27.2% to the yield of 536.8 mg/L. The β-carotene hydroxylase gene crtZ was then transferred, resulting in a yield of zeaxanthin of 326.5 mg/L. The oxidoreductase RFNR1 and CrtZ were then used to further enhance zeaxanthin production, and the yield of zeaxanthin was up to 775.3 mg/L in YPD shake flask.

A machine learning approach for understanding the metabolomics response of children with autism spectrum disorder to medical cannabis treatment

Autism spectrum disorder (ASD) is a neurodevelopmental condition impacting behavior, communication, social interaction and learning abilities. Medical cannabis (MC) treatment can reduce clinical symptoms in individuals with ASD. Cannabis-responsive biomarkers are metabolites found in saliva that change in response to MC treatment. Previously we showed levels of these biomarkers in children with ASD successfully treated with MC shift towards the physiological levels detected in typically developing (TD) children, and potentially can quantify the impact. Here, we tested for the first time the capabilities of machine learning techniques applied to our dynamic, high-resolution and rich feature dataset of cannabis-responsive biomarkers from a limited number of children with ASD before and after MC treatment and a TD group to identify: (1) biomarkers distinguishing ASD and TD groups; (2) non-cannabinoid plant molecules with synergistic effects; and (3) biomarkers associated with specific cannabinoids. We found: (1) lysophosphatidylethanolamine can distinguish between ASD and TD groups; (2) novel phytochemicals contribute to the therapeutic effects of MC treatment by inhibition of acetylcholinesterase; and (3) THC- and CBD-associated cannabis-responsive biomarkers are two distinct groups, while CBG is associated with some biomarkers from both groups.

Exploring the therapeutic efficacy of Chlorella pyrenoidosa peptides in ameliorating Alzheimer's disease

Alzheimer's disease (AD) is one of the neurodegenerative disorders, the hallmarks of which include deposits of extracellular beta-amyloid (Aβ) as well as intracellular tau neurofibrillary tangles (NFTs) tangles. With disease progression, neuronal apoptosis combined with cerebral atrophy occurs, leading to cognitive impairment and long-term memory loss. Recently, Chlorella species have been identified as a functional food and are being explored for the prevention of various diseases widely studied to prevent or treat many neurodegenerative diseases. Hence, we for the first time investigated the neuroprotective effects of Chlorella pyrenoidosa short-chain peptides (CPPs) i.e. <1 kDa, 1-3 kDa, 3-10 kDa, and >10 kDa on the in vitro and in vivo neuronal injury models. Our in vitro results showed that CPP with a molecular weight of 1-3 kDa and 3-10 kDa could elevate the survival rate of Aβ_1-42 or l-Glutamic acid-injured N2A cells. These treatments also inhibited Aβ and tau NFTs in N2A cells and prevented progressive neuronal cellular damage by suppressing inflammatory cytokines such as PGE2, iNOS, IL-6, TNF-α, COX-2, IL-1β, TGF-β1, and NF-κB. Further, our in vivo Aβ_1-42-induced AD mice model demonstrated that 1-3 kDa or 3-10 kDa CPP could improve spatial cognition and learning memory. We also observed a decreased cell loss ratio in CA1-CA3 hippocampal regions. Taken together, our findings imply that CPPs may exert their anti-AD impact through anti-inflammatory, and anti-amyloid activities via reducing APP and tau NFT.

Dunaliella salina Microalga Restores the Metabolic Equilibrium and Ameliorates the Hepatic Inflammatory Response Induced by Zinc Oxide Nanoparticles (ZnO-NPs) in Male Zebrafish

Microalgae are rich in bioactive compounds including pigments, proteins, lipids, polyunsaturated fatty acids, carbohydrates, and vitamins. Due to their non-toxic and nutritious characteristics, these are suggested as important food for many aquatic animals. Dunaliella salina is a well-known microalga that accumulates valuable amounts of carotenoids. We investigated whether it could restore the metabolic equilibrium and mitigate the hepatic inflammation induced by zinc oxide nanoparticles (ZnO-NPs) using male zebrafish which were exposed to 1/5^th 96 h-LC₅₀ for 4 weeks, followed by dietary supplementation with D. salina at two concentrations (15% and 30%) for 2 weeks. Collectively, ZnO-NPs affected fish appetite, whole body composition, hepatic glycogen and lipid contents, intestinal bacterial and Aeromonas counts, as well as hepatic tumor necrosis factor- α (TNF-α). In addition, the mRNA expression of genes related to gluconeogenesis (pck1, gys2, and g6pc3), lipogenesis (srepf1, acaca, fasn, and cd36), and inflammatory response (tnf-α, tnf-β, nf-kb2) were modulated. D. salina reduced the body burden of zinc residues, restored the fish appetite and normal liver architecture, and mitigated the toxic impacts of ZnO-NPs on whole-body composition, intestinal bacteria, energy metabolism, and hepatic inflammatory markers. Our results revealed that the administration of D. salina might be effective in neutralizing the hepatotoxic effects of ZnO-NPs in the zebrafish model.