Epimorphic regeneration in vertebrates involves the restoration of lost tissue or organs through the formation of a regeneration blastema and occurs through a complex interaction of a number of molecular signaling pathways. Of the many effectors of successful tail regeneration in the lizard Hemidactylus flaviviridis, one crucial pathway is the cyclooxygenase-2 (COX-2) mediated PGE2 signaling pathway. The current study was aimed at understanding whether COX-2 signaling plays any role in the expression of Wnt/β-Catenin signaling components during regenerative outgrowth in H. flaviviridis. Etoricoxib—selective inhibitor of the inducible isoform of COX-2—was administered to lizards orally. We tested the expression of β-Catenin during wound epidermis and blastema stages in the regenerating tail and found a reduction in its expression in response to drug treatment. Further, it was observed that the expression of canonical Wnt ligands was greatly altered due to COX-2 inhibition. Our results provide evidence of a cross-talk between the COX-2 induced PGE₂ pathway and Wnt/β-Catenin signaling in the regenerating lizard tail. An understanding of the interaction among various signaling pathways will help elucidate the mechanism underlying epimorphosis in lizards, the only amniotes capable of appendage regeneration.
beta Catenin ; Cyclooxygenase 2* ; Dinoprostone ; Epidermis ; Inflammation ; Ligands ; Lizards* ; Prostaglandin-Endoperoxide Synthases ; Regeneration ; Tail* ; Vertebrates ; Wounds and Injuries

Purpose: In the United States, Pfizer-BioNTech, Moderna, and Janssen’s coronavirus disease 2019 (COVID-19) vaccines have been granted Emergency Use Authorization (EUA) with the Pfizer-BioNTech vaccine presently approved by the US Food and Drug Administration. The purpose of this study is to analyze passive surveillance data on COVID-19 vaccine adverse reaction in the United States. Materials and Methods: We analyzed passive surveillance data on COVID-19 vaccine adverse reactions which were retrieved from the Vaccine Adverse Event Reporting System database. Retrieved records on demographic information as well as the top 10 common vaccine adverse events were extracted and assessed from 200 of the most recently reported cases for the study analysis. Results: Local and systemic adverse reactions were reported in the study. A significant difference (p<0.05) was recorded for the top 10 systemic reactions by age category (0.041) and by gender (0.002). Analysis of the top five systemic reactions, stratified by vaccine type yielded a significant difference (p<0.05) for chills (p=0.044), and when stratified by age group and type of vaccination received, it yielded a significant difference (p<0.05) for fatigue (p=0.023). Overall, Pfizer had 182 persons (91.0%) reporting adverse events, Moderna with 13 (6.5%), and Janssen with 5 (2.5%). Conclusion Mild side effects were reported following vaccination with the EUA COVID-19 vaccines in the United States. Thus, continuous monitoring and reporting of all adverse events are recommended to ensure the safety of vaccination.