miRNA Expression Profiles in Isolated Ventricular Cardiomyocytes: Insights into Doxorubicin-Induced Cardiotoxicity.

Doxorubicin (DOX), widely used as a chemotherapeutic agent for various cancers, is limited in its clinical utility by its cardiotoxic effects. Despite its widespread use, the precise mechanisms underlying DOX-induced cardiotoxicity at the cellular and molecular levels remain unclear, hindering the development of preventive and early detection strategies. To characterize the cytotoxic effects of DOX on isolated ventricular cardiomyocytes, focusing on the expression of specific microRNAs (miRNAs) and their molecular targets associated with endogenous cardioprotective mechanisms such as the ATP-sensitive potassium channel (KATP), Sirtuin 1 (SIRT1), FOXO1, and GSK3ß. We isolated Guinea pig ventricular cardiomyocytes by retrograde perfusion and enzymatic dissociation. We assessed cell morphology, Reactive Oxygen Species (ROS) levels, intracellular calcium, and mitochondrial membrane potential using light microscopy and specific probes. We determined the miRNA expression profile using small RNAseq and validated it using stem-loop qRT-PCR. We quantified mRNA levels of some predicted and validated molecular targets using qRT-PCR and analyzed protein expression using Western blot. Exposure to 10 µM DOX resulted in cardiomyocyte shortening, increased ROS and intracellular calcium levels, mitochondrial membrane potential depolarization, and changes in specific miRNA expression. Additionally, we observed the differential expression of KATP subunits (ABCC9, KCNJ8, and KCNJ11), FOXO1, SIRT1, and GSK3ß molecules associated with endogenous cardioprotective mechanisms. Supported by miRNA gene regulatory networks and functional enrichment analysis, these findings suggest that DOX-induced cardiotoxicity disrupts biological processes associated with cardioprotective mechanisms. Further research must clarify their specific molecular changes in DOX-induced cardiac dysfunction and investigate their diagnostic biomarkers and therapeutic potential.

Zebrafish and Artemia salina in vivo evaluation of the recreational 25C-NBOMe drug demonstrates its high toxicity.

The NBOMe (N-2-methoxybenzyl-phenethylamines) family of compounds are synthetic hallucinogens derived from the 2C series. Although this family of compounds has been responsible for multiple cases of acute toxicity and several deaths around the world, to date there are few studies. These compounds act as potent 5-HT2A receptor agonists, including the hallucinogen 25C-NBOMe (2-(4-chloro-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine). In this study, we first evaluated the toxicity of 25C-NBOMe in two animal models: Artemia salina and zebrafish using the lethality test of Meyer et al. (1982) modified for Artemia salina and the Fish Embryo Toxicity test (FET) for zebrafish (Danio rerio). Subsequently, we determined the behavioral and morphological effects using different concentrations of the 25C-NBOMe. As a result, we found that this substance is highly toxic according to lethality tests in both animal models. We also observe that this hallucinogen induces alterations in swimming and motility patterns in Artemia salina. Similarly, there were alterations in the motor response to a stimulus, as well as abnormal development in the zebrafish. The developmental effects of zebrafish suggest a teratogenic potential for 25C-NBOMe. Therefore, these findings are correlated with side effects, such as motor response abnormalities and muscle deterioration, clinically reported for consumers of this recreational drug. Finally, although recent studies are addressing the neurotoxicity and cardiotoxicity of 25C-NBOMe in cell cultures, to the best of our knowledge, this is the first in vivo report for 25C-NBOMe related to toxicological parameters and their global effects on development. Therefore, it could represent an advance in the study of the substance that contributes to the understanding of the effects on behavior and development in humans.