Short-term exposure to the simple polyphenolic compound gallic acid induces neuronal hyperactivity in zebrafish larvae

Transcriptomic Point of Departure (tPOD) of androstenedione in zebrafish embryos as a potential surrogate for chronic endpoints

The transcriptomic Point of Departure (tPOD) is increasingly used in ecotoxicology to derive quantitative endpoints from RNA sequencing studies. Utilizing transcriptomic data in zebrafish embryos as a New Approach Methodology (NAM) is beneficial due to its acknowledgment as an alternative to animal testing under EU Directive 2010/63/EU. Transcriptomic profiles are available in zebrafish for various modes of action (MoA). The limited literature available suggest that tPOD values from Fish Embryo Toxicity (FET) tests align with, but are generally lower than, No Observed Effect Concentrations (NOEC) from long-term chronic fish toxicity tests. In studies with the androgenic hormone androstenedione in a Fish Sexual Development Test (FSDT), a significant shift in the sex ratio towards males was noted at all test concentrations, making it impossible to determine a NOEC (NOEC <4.34 μg/L). To avoid additional animal testing in a repetition of the FSDT and adhere to the 3Rs principle (replacement, reduction, and refinement), a modified zebrafish FET (zFET) was conducted aiming to determine a regulatory acceptable effect threshold. This involved lower concentration ranges (20 to 6105 ng/L), overlapping with the masculinization-observed concentrations in the FSDT. The tPOD analysis in zFET showed consistent results with previous FSDT findings, observing strong expression changes in androgen-dependent genes at higher concentrations but not at lower ones, demonstrating a concentration-response relationship. The tPOD values for androstenedione were determined as 24 ng/L (10th percentile), 60 ng/L (20th gene), and 69 ng/L (1st peak). The 10th percentile tPOD value in zFET was 200 times lower than the lowest concentration in the FSDT. Comparing the tPOD values to literature suggests their potential to inform on the NOEC range in FSDT tests.

Comparative Study of Condensed and Hydrolysable Tannins during the Early Stages of Zebrafish Development

In this study, we present data on the effects of condensed tannins (CTs) and hydrolysable tannins (HTs), polyphenols extracted from plants, at different concentrations on zebrafish development to identify the range of concentrations with toxic effects. Zebrafish embryos were exposed to CTs and HTs at two different concentration ranges (5.0-20.0 μgL-1 and 5.0-20.0 mgL-1) for 72 h. The toxicity parameters were observed up to 72 h of treatment. The uptake of CTs and HTs by the zebrafish larvae was assessed via HPLC analysis. A qRT-PCR analysis was performed to evaluate the expressions of genes cd63, zhe1, and klf4, involved in the hatching process of zebrafish. CTs and HTs at 5.0, 10.0, and 20.0 μgL-1 were not toxic. On the contrary, at 5.0, 10.0, and 20.0 mgL-1, HTs induced a delay in hatching starting from 48 h of treatment, while CTs showed a delay in hatching mainly at 48 h. The analysis of gene expression showed a downregulation in the group exposed to HTs, confirming the hatching data. We believe that this study is important for defining the optimal doses of CTs and HTs to be employed in different application fields such as the chemical industry, the animal feed industry, and medical science.

Integration of single-nucleus RNA sequencing and network disturbance to elucidate crosstalk between multicomponent drugs and trigeminal ganglia cells in migraine

ETHNOPHARMACOLOGICAL RELEVANCE

Migraine is caused by hyperactivity of the trigeminovascular system, where trigeminal ganglia (TG) plays an important role. TG is composed of multiple neuronal and non-neuronal cell types, which is related to "neuro-inflammation-vascular" disorder in migraine. Tou Tong Ning capsule (TTNC), a CFDA-approved traditional Chinese medicine for treating migraine, has the characteristics of "multicomponents, multitargets, multipathways".

AIM OF THE STUDY

To clarify the mechanism of TTNC and elucidate crosstalk between multicomponent drugs and neuronal and non-neuronal functions and cells in migraine.

MATERIALS AND METHODS

We integrated single-nucleus RNA sequencing and a quantitative evaluation algorithm of the disturbance of multitarget drugs on the disease network and explored the specific pathology of migraine and corresponding compounds. A cerebrovascular smooth muscle spasmolytic activity experiment was carried out to verify the results of the bioinformatics analysis.

RESULTS

TTNC exhibited its regulation activities in neuronal and non-neuronal aspects based on drugs attack to four subnetworks and cell specific networks, which explored the MoA of TTNC in comprehensive and refined perspectives. Compared to neuronal regulation, TTNC showed more significant attack score on non-neuronal biological function (smooth muscle and vessel). And TTNC compound clusters C1, C6 and C7, targeting non-neuronal function and cells, had larger group area than C10, C4 and C6 for neuronal function and cell, which implied that TTNC may mainly regulate the non-neuronal function, e.g., vessel smooth muscle contraction. Contraction of cerebrovascular smooth muscle of mice ex vivo confirmed the vasodilation activity of TTNC and active compounds from C1, C6, C9 (Emodin, Luteolin and Levistilide A). Literature mining confirmed the vasospasmodolytic activity and neuroprotective effect of TTNC.

CONCLUSIONS

The study found that TTNC may primarily alleviate non-neuronal functional disorders in migraine by relaxing cerebral vascular smooth muscle cell spasm to alleviate migraine. Integrating single-nucleus RNA sequencing data and network disturbance tools provides a new strategy for the pharmacological mechanism of multicomponent drugs through cell subtyping.

Antioxidant, Pro-Survival and Pro-Regenerative Effects of Conditioned Medium from Wharton's Jelly Mesenchymal Stem Cells on Developing Zebrafish Embryos

Conditioned media harvested from stem cell culturing have the potential to be innovative therapeutic tools against various diseases, due to their high content of growth, trophic and protective factors. The evaluation in vivo of the effects and biosafety of these products is essential, and zebrafish provides an ideal platform for high-throughput toxicological analysis, concurrently allowing the minimization of the use of mammalian models without losing reliability. In this study, we assessed the biological effects elicited by the exposure of zebrafish embryos to a conditioned medium derived from Wharton's jelly mesenchymal stem cells. By a multiparametric investigation combining molecular, embryological, behavioural and in vivo imaging techniques, we found that exposure to a conditioned medium at a non-toxic/non-lethal dosage triggers antioxidant, anti-apoptotic and pro-regenerative effects, by upregulation of a set of genes involved in antioxidant defence (nrf2, brg1, sirt1, sirt6, foxO3a, sod2 and cat), glycolysis (ldha) and cell survival (bcl2l1, mcl1a and bim), coupled to downregulation of pro-apoptotic markers (baxa, caspase-3a and caspase-8). To our knowledge, this is the first study comprehensively addressing the effects of a conditioned medium on a whole organism from a developmental, molecular and behavioural perspective, and we are fairly confident that it will pave the way for future therapeutic application.

Antiparkinsonian Effects of Polyphenols: A Narrative Review with a Focus on the Modulation of the Gut-brain Axis

Polyphenols, which are naturally occurring bioactive compounds in fruits and vegetables, are emerging as potential therapeutics for neurological disorders such as Parkinson's disease (PD). Polyphenols have diverse biological activities, such as anti-oxidative, anti-inflammatory, anti-apoptotic, and α-synuclein aggregation inhibitory effects, which could ameliorate PD pathogenesis. Studies have shown that polyphenols are capable of regulating the gut microbiota (GM) and its metabolites; in turn, polyphenols are extensively metabolized by the GM, resulting in the generation of bioactive secondary metabolites. These metabolites may regulate various physiological processes, including inflammatory responses, energy metabolism, intercellular communication, and host immunity. With increasing recognition of the importance of the microbiota-gut-brain axis (MGBA) in PD etiology, polyphenols have attracted growing attention as MGBA regulators. In order to address the potential therapeutic role of polyphenolic compounds in PD, we focused on MGBA. DATA AVAILABILITY: Data will be made available on request.

Transgenerational effects of androstadienedione and androstenedione at environmentally relevant concentrations in zebrafish (Danio rerio)

Androgens androstadienedione (ADD) and androstenedione (AED) are predominant steroid hormones in surface water, and can disrupt the endocrine system in fish. However, little is known about the transgenerational effects of ADD and AED in fish. In the present study, F0 generation was exposed to ADD and AED from 21 to 144 days post-fertilization (dpf) at nominal concentrations of 5 (L), 50 (M) and 500 (H) ng L^-1, and F1 generation was domesticated in clear water for 144 dpf. The sex ratio, histology and transcription in F0 and F1 generations were examined. In the F0 generation, ADD and AED tended to be estrogenic in zebrafish, resulting in female biased zebrafish populations. In the F1 generation, ADD at the H level caused 63.5% females, while AED at the H level resulted in 78.7% males. In brain, ADD and AED had similar effects on circadian rhythm in the F0 and F1 generations. In the F1 eleutheroembryos, transcriptomic analysis indicated that neuromast hair cell related biological processes (BPs) were overlapped in the ADD and AED groups. Taken together, ADD and AED at environmentally relevant concentrations had transgenerational effects on sex differentiation and transcription in zebrafish.

Overview of Beneficial Effects of (Poly)phenol Metabolites in the Context of Neurodegenerative Diseases on Model Organisms

The rise of neurodegenerative diseases in an aging population is an increasing problem of health, social and economic consequences. Epidemiological and intervention studies have demonstrated that diets rich in (poly)phenols can have potent health benefits on cognitive decline and neurodegenerative diseases. Meanwhile, the role of gut microbiota is ever more evident in modulating the catabolism of (poly)phenols to dozens of low molecular weight (poly)phenol metabolites that have been identified in plasma and urine. These metabolites can reach circulation in higher concentrations than parent (poly)phenols and persist for longer periods of time. However, studies addressing their potential brain effects are still lacking. In this review, we will discuss different model organisms that have been used to study how low molecular weight (poly)phenol metabolites affect neuronal related mechanisms gathering critical insight on their potential to tackle the major hallmarks of neurodegeneration.