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In vitro manipulation of induced pluripotent stem cells (iPSCs) by environmental factors is of great interest for three-dimensional (3D) tissue/organ induction. The effects of mechanical force depend on many factors, including force and cell type. However, information on such effects in iPSCs is lacking. The aim of this study was to identify a molecular mechanism in iPSCs responding to intermittent compressive force (ICF) by analyzing the global gene expression profile. Embryoid bodies of mouse iPSCs, attached on a tissue culture plate in 3D form, were subjected to ICF in serum-free culture medium for 24 h. Gene ontology analyses for RNA sequencing data demonstrated that genes differentially regulated by ICF were mainly associated with metabolic processes, membrane and protein binding. Topology-based analysis demonstrated that ICF induced genes in cell cycle categories and downregulated genes associated with metabolic processes. The Kyoto Encyclopedia of Genes and Genomes database revealed differentially regulated genes related to the p53 signaling pathway and cell cycle. qPCR analysis demonstrated significant upregulation of Ccnd1, Cdk6 and Ccng1. Flow cytometry showed that ICF induced cell cycle and proliferation, while reducing the number of apoptotic cells. ICF also upregulated transforming growth factor β1 (Tgfb1) at both mRNA and protein levels, and pretreatment with a TGF-β inhibitor (SB431542) prior to ICF abolished ICF-induced Ccnd1 and Cdk6 expression. Taken together, these findings show that TGF-β signaling in iPSCs enhances proliferation and decreases apoptosis in response to ICF, that could give rise to an efficient protocol to manipulate iPSCs for organoid fabrication.

Potential aerosols containing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral particles can be generated during dental treatment. Hence, patient triage is essential to prevent the spread of SARS-CoV-2 in dental clinical settings. The present study described the use of rapid antigen tests for SARS-CoV-2 screening prior to dental treatment in an academic dental clinical setting in Thailand during the pandemic. The opinions of dental personnel toward the use of rapid antigen test screening prior to dental treatment were also assessed. From August 25 to October 3, 2021, dental patients who were expected to receive aerosols generating dental procedures were requested to screen for SARS-CoV-2 using a rapid antigen test before their treatment. A total of 7,618 cases completed the screening process. The average was 212 cases per day. Only five patients (0.07%) were positive for SARS-CoV-2 in the rapid antigen screening tests. All positive cases exhibited mild symptoms. For the questionnaire study, experienced dental personnel frequently and consistently agreed with the use of the rapid antigen test for SARS-CoV-2 screening, which made them feel safer during their patient treatment. However, implementing rapid antigen tests for SARS-CoV-2 may increase the total time spent on a dental appointment. In conclusion, a rapid antigen test could detect the infected individual prior to dental treatment. However, the specificity of rapid antigen tests for SARS-CoV-2 must be taken into account for consideration as a screening process before dental treatment. The enhanced infection control protocols in dental treatment must be consistently implemented.