biostudies-literatureVisca HNIGMS NIH HHS874-885https://www.ebi.ac.uk/biostudies/studies/S-EPMC9681937biostudies-literatureUnknown24(6)<h4>Purpose</h4>Acidity can be a useful alternative biomarker for the targeting of metabolically active cells in certain diseased tissues, as in acute inflammation or aggressive tumors. We investigated the targeting of activated macrophages by pH low insertion peptides (pHLIPs), an established technology for targeting cell-surface acidity.<h4>Procedures</h4>The uptake of fluorescent pHLIPs by activated macrophages was studied in cell cultures, in a mouse model of lung inflammation, and in a mouse tumor model. Fluorescence microscopy, whole-body and organ imaging, immunohistochemistry, and FACS analysis were employed.<h4>Results</h4>We find that cultured, activated macrophages readily internalize pHLIPs. The uptake is higher in glycolytic macrophages activated by LPS and INF-γ compared to mMolecular imaging and biologypHLIP Peptides Target Acidity in Activated Macrophages.PMC9681937P20 GM103430R01 GM073857Visca HEngelman DMCrawford TMoshnikova AReshetnyak YKDuPont MAndreev OAfalsepHLIP Peptides Target Acidity in Activated Macrophages.<h4>Purpose</h4>Acidity can be a useful alternative biomarker for the targeting of metabolically active cells in certain diseased tissues, as in acute inflammation or aggressive tumors. We investigated the targeting of activated macrophages by pH low insertion peptides (pHLIPs), an established technology for targeting cell-surface acidity.<h4>Procedures</h4>The uptake of fluorescent pHLIPs by activated macrophages was studied in cell cultures, in a mouse model of lung inflammation, and in a mouse tumor model. Fluorescence microscopy, whole-body and organ imaging, immunohistochemistry, and FACS analysis were employed.<h4>Results</h4>We find that cultured, activated macrophages readily internalize pHLIPs. The uptake is higher in glycolytic macrophages activated by LPS and INF-γ compared to m2022-01-01T00:00:00Z2022 Dec2025-04-21T23:08:30.88Z2025-04-05T19:04:36.312ZS-EPMC96819373560452710.1007/s11307-022-01737-x