Modulation of Naive CD8 T Cell Response Features by Ligand Density, Affinity, and Continued Signaling via Internalized TCRs.

T cell response magnitudes increase with increasing antigenic dosage. However, it is unclear whether ligand density only modulates the proportions of responding ligand-specific T cells or also alters responses at the single cell level. Using brief (3 h) exposure of TCR-transgenic mouse CD8 T cells in vitro to varying densities of cognate peptide-MHC ligand followed by ligand-free culture in IL-2, we found that ligand density determined the frequencies of responding cells but not the expression levels of the early activation marker molecule, CD69. Cells with low glucose uptake capacity and low protein synthesis rates were less ligand-sensitive, implicating metabolic competence in the response heterogeneity of CD8 T cell populations. Although most responding cells proliferated, ligand density was associated with time of entry into proliferation and with the extent of cell surface TCR downmodulation. TCR internalization was associated, regardless of the ligand density, with rapidity of c-myc induction, loss of the cell cycle inhibitor p27kip1, metabolic reprogramming, and cell cycle entry. A low affinity peptide ligand behaved, regardless of ligand density, like a low density, high affinity ligand in all these parameters. Inhibition of signaling after ligand exposure selectively delayed proliferation in cells with internalized TCRs. Finally, internalized TCRs continued to signal and genetic modification of TCR internalization and trafficking altered the duration of signaling in a T cell hybridoma. Together, our findings indicate that heterogeneity among responding CD8 T cell populations in their ability to respond to TCR-mediated stimulation and internalize TCRs mediates detection of ligand density or affinity, contributing to graded response magnitudes.

Role of microRNAs as biomarkers of cervical carcinogenesis: a systematic review

We performed a systematic review to identify the role of microRNAs (miRNAs) as biomarkers in the progression of cervical precancerous lesions. A comprehensive search of the Cochrane Controlled Register of Trials, PubMed, ScienceDirect, and Embase databases was performed for articles published between January 2010 and June 2020. The following Medical Subject Headings (MeSH) terms were searched: “microRNA” and “cervical” and “lesion.” All study designs that aimed to evaluate the correlation of miRNA expression with different precancerous cervical staging and/or cervical cancer were included, except for case reports and case series. Approximately 82 individual miRNAs were found to be significant in differentiating the stages of cervical carcinogenesis. Among the miRNAs, miR-21 is the most prevalent, and it is consistently upregulated progressively from normal cervical to worsening cervical lesion stages in both cell and serum samples. miR-205 has been shown to have a higher specificity than human papilloma virus testing in predicting the absence of high-grade squamous intraepithelial lesions (HSILs) in exfoliated cell samples. The tumor suppressor miRNAs miR-34, let-7, miR-203 miR-29, and miR-375 were significantly downregulated in low-grade squamous intraepithelial lesions, HSILs, and cervical cancer. We found significant dysregulated miRNAs in cervical carcinogenesis with their dynamic expression changes and ability to detect viral persistency, risk prediction of low-grade lesions (cervical intraepithelial neoplasia [CIN] 2) to high-grade lesions (CIN 3), and progression of CIN 3 to cancer. Their ability to discriminate HSILs from non-dysplastic lesions has potential implications in early diagnosis and reducing overtreatment of otherwise regressive early preinvasive lesions.

Role of microRNAs as biomarkers of cervical carcinogenesis: a systematic review

We performed a systematic review to identify the role of microRNAs (miRNAs) as biomarkers in the progression of cervical precancerous lesions. A comprehensive search of the Cochrane Controlled Register of Trials, PubMed, ScienceDirect, and Embase databases was performed for articles published between January 2010 and June 2020. The following Medical Subject Headings (MeSH) terms were searched: “microRNA” and “cervical” and “lesion.” All study designs that aimed to evaluate the correlation of miRNA expression with different precancerous cervical staging and/or cervical cancer were included, except for case reports and case series. Approximately 82 individual miRNAs were found to be significant in differentiating the stages of cervical carcinogenesis. Among the miRNAs, miR-21 is the most prevalent, and it is consistently upregulated progressively from normal cervical to worsening cervical lesion stages in both cell and serum samples. miR-205 has been shown to have a higher specificity than human papilloma virus testing in predicting the absence of high-grade squamous intraepithelial lesions (HSILs) in exfoliated cell samples. The tumor suppressor miRNAs miR-34, let-7, miR-203 miR-29, and miR-375 were significantly downregulated in low-grade squamous intraepithelial lesions, HSILs, and cervical cancer. We found significant dysregulated miRNAs in cervical carcinogenesis with their dynamic expression changes and ability to detect viral persistency, risk prediction of low-grade lesions (cervical intraepithelial neoplasia [CIN] 2) to high-grade lesions (CIN 3), and progression of CIN 3 to cancer. Their ability to discriminate HSILs from non-dysplastic lesions has potential implications in early diagnosis and reducing overtreatment of otherwise regressive early preinvasive lesions.

Root canal irrigants influence the hydrophobicity and adherence of Staphylococcus epidermidis to root canal dentin: an in vitro study

OBJECTIVES: To determine the effect of root canal irrigants on the hydrophobicity and adherence of Staphylococcus epidermidis (S. epidermidis) to root canal dentin in vitro. MATERIALS AND METHODS: Root dentin blocks (n = 60) were randomly divided into 4 groups based on the irrigation regimen: group 1, saline; group 2, 5.25% sodium hypochlorite (NaOCl); group 3, 5.25% NaOCl followed by 17% ethylenediaminetetraacetic acid (EDTA); group 4, same as group 3 followed by 2% chlorhexidine (CHX). The hydrophobicity of S. epidermidis to root dentin was calculated by cell surface hydrophobicity while the adherence was observed by fluorescence microscopy, and bacteria were quantified using ImageJ software (National Institutes of Health). Statistical analysis of the data was done using Kruskal-Wallis test and Mann-Whitney U test (p = 0.05). RESULTS: The hydrophobicity and adherence of S. epidermidis to dentin were significantly increased after irrigating with group 3 (NaOCl-EDTA) (p < 0.05), whereas in group 4 (NaOCl-EDTA-CHX) both hydrophobicity and adherence were significantly reduced (p < 0.05). CONCLUSIONS: The adherence of S. epidermidis to dentin was influenced differently by root canal irrigants. Final irrigation with CHX reduces the bacterial adherence and may impact biofilm formation.