Senescent skeletal muscle fibroadipogenic progenitors recruit and promote M2 polarization of macrophages.

Senescent cells compromise tissue structure and function in older organisms. We recently identified senescent fibroadipogenic progenitors (FAPs) with activated chemokine signaling pathways in the skeletal muscle of old mice, and hypothesized these cells may contribute to the age-associated accumulation of immune cells in skeletal muscle. In this study, through cell-cell communication analysis of skeletal muscle single-cell RNA-sequencing data, we identified unique interactions between senescent FAPs and macrophages, including those mediated by Ccl2 and Spp1. Using mouse primary FAPs in vitro, we verified increased expression of Ccl2 and Spp1 and secretion of their respective proteins in the context of both irradiation- and etoposide-induced senescence. Compared to non-senescent FAPs, the medium of senescent FAPs markedly increased the recruitment of macrophages in an in vitro migration assay, an effect that was mitigated by preincubation with antibodies to either CCL2 or osteopontin (encoded by Spp1). Further studies demonstrated that the secretome of senescent FAPs promotes polarization of macrophages toward an M2 subtype. These data suggest the unique secretome of senescent FAPs may compromise skeletal muscle homeostasis by recruiting and directing the behavior of macrophages.

Single-cell Mayo Map (scMayoMap): an easy-to-use tool for cell type annotation in single-cell RNA-sequencing data analysis.

BACKGROUND: Single-cell RNA-sequencing (scRNA-seq) has become a widely used tool for both basic and translational biomedical research. In scRNA-seq data analysis, cell type annotation is an essential but challenging step. In the past few years, several annotation tools have been developed. These methods require either labeled training/reference datasets, which are not always available, or a list of predefined cell subset markers, which are subject to biases. Thus, a user-friendly and precise annotation tool is still critically needed. RESULTS: We curated a comprehensive cell marker database named scMayoMapDatabase and developed a companion R package scMayoMap, an easy-to-use single-cell annotation tool, to provide fast and accurate cell type annotation. The effectiveness of scMayoMap was demonstrated in 48 independent scRNA-seq datasets across different platforms and tissues. Additionally, the scMayoMapDatabase can be integrated with other tools and further improve their performance. CONCLUSIONS: scMayoMap and scMayoMapDatabase will help investigators to define the cell types in their scRNA-seq data in a streamlined and user-friendly way.

Single-cell Mayo Map ( scMayoMap ): an easy-to-use tool for cell type annotation in single-cell RNA-sequencing data analysis.

Single-cell RNA-sequencing (scRNA-seq) has become a widely used tool for both basic and translational biomedical research. In scRNA-seq data analysis, cell type annotation is an essential but challenging step. In the past few years, several annotation tools have been developed. These methods require either labeled training/reference datasets, which are not always available, or a list of predefined cell subset markers, which are subject to biases. Thus, a user-friendly and precise annotation tool is still critically needed. We curated a comprehensive cell marker database named scMayoMapDatabase and developed a companion R package scMayoMap , an easy-to-use single cell annotation tool, to provide fast and accurate cell type annotation. The effectiveness of scMayoMap was demonstrated in 48 independent scRNA-seq datasets across different platforms and tissues. scMayoMap performs better than the currently available annotation tools on all the datasets tested. Additionally, the scMayoMapDatabase can be integrated with other tools and further improve their performance. scMayoMap and scMayoMapDatabase will help investigators to define the cell types in their scRNA-seq data in a streamlined and user-friendly way.

Comparative Efficacy of Different Amoxicillin Dosing Regimens in Preventing Early Implant Failure-A Systematic Review with Network Meta-Analysis.

This systematic review and network meta-analysis aimed to assess the comparative efficacy and safety of antibiotics to prevent early implant failure in patients undergoing dental implant surgery. METHODS: The review was registered in PROSPERO [CRD42022319385]. A search was conducted for trials published in Medline, Cochrane, PubMed, and Scopus. A network meta-analysis was performed on the data from randomized controlled trials. Agents were ranked according to their effectiveness based on outcomes (implant failure, prosthetic failure, postsurgical complications, and adverse effects) using the surface under the cumulative ranking [SUCRA]. RESULTS: A total of 15 articles were included in the quantitative analysis. When compared to the placebo, 2 g of amoxicillin given 1 h preoperatively (RR = 0.42 (95%CI: 0.27, 0.67)), 2 g of amoxicillin given 1 h preoperatively with postoperative 500 mg thrice for 5 days (RR = 0.36 (95%CI: 0.15, 0.87)), and post-operative amoxicillin with clavulanic acid 625 mg 3 times daily for 5 days (RR = 0.38 (95%CI: 0.16, 0.90)) were effective in reducing early implant failures. In addition, 2 g of amoxicillin given 1 h preoperatively (RR = 0.42 (95%CI: 0.25, 0.73)) was the only protocol that was significant in the pairwise meta-analysis results. However, sensitivity analysis, which excluded trials with a high risk of bias, showed that none of the protocols were statistically significant in reducing early implant failure. CONCLUSIONS: A single 2 g dose of preoperative amoxicillin significantly reduces early implant failure in healthy individuals. More high-quality trials are required to establish this recommendation, as the quality of this evidence is weak.

Characterization of cellular senescence in aging skeletal muscle.

Senescence is a cell fate that contributes to multiple aging-related pathologies. Despite profound age-associated changes in skeletal muscle (SkM), whether its constituent cells are prone to senesce has not been methodically examined. Herein, using single cell and bulk RNA-sequencing and complementary imaging methods on SkM of young and old mice, we demonstrate that a subpopulation of old fibroadipogenic progenitors highly expresses p16 Ink4a together with multiple senescence-related genes and, concomitantly, exhibits DNA damage and chromatin reorganization. Through analysis of isolated myofibers, we also detail a senescence phenotype within a subset of old cells, governed instead by p2 Cip1 . Administration of a senotherapeutic intervention to old mice countered age-related molecular and morphological changes and improved SkM strength. Finally, we found that the senescence phenotype is conserved in SkM from older humans. Collectively, our data provide compelling evidence for cellular senescence as a hallmark and potentially tractable mediator of SkM aging.