Surface-bound matrix metalloproteinase-8 on macrophages: Contributions to macrophage pericellular proteolysis and migration through tissue barriers.

Objective: MMP-8 binds to surface-bound tissue inhibitor of metalloproteinase-1 (TIMP-1) on PMNs to promote pericellular proteolysis during the development of inflammatory diseases associated with tissue destruction. Little is known about the biology of MMP-8 in macrophages. We tested the hypotheses that: (1) MMP-8 and TIMP-1 are also expressed on the surface of activated macrophages, (2) surface-bound MMP-8 on macrophages promotes TIMP-resistant pericellular proteolysis and macrophage migration through tissue barriers, and (3) MMP-8 binds to surface-bound TIMP-1 on macrophages.

The 3D OrbiSIMS-label-free metabolic imaging with subcellular lateral resolution and high mass-resolving power.

We report the development of a 3D OrbiSIMS instrument for label-free biomedical imaging. It combines the high spatial resolution of secondary ion mass spectrometry (SIMS; under 200 nm for inorganic species and under 2 μm for biomolecules) with the high mass-resolving power of an Orbitrap (>240,000 at m/z 200). This allows exogenous and endogenous metabolites to be visualized in 3D with subcellular resolution.

Intracellular Drug Uptake-A Comparison of Single Cell Measurements Using ToF-SIMS Imaging and Quantification from Cell Populations with LC/MS/MS.

ToF-SIMS is a label-free imaging method that has been shown to enable imaging of amiodarone in single rat macrophage (NR8383) cells. In this study, we show that the method extends to three other cell lines relevant to drug discovery: human embryonic kidney (HEK293), cervical cancer (HeLa), and liver cancer (HepG2). There is significant interest in the variation of drug uptake at the single cell level, and we use ToF-SIMS to show that there is great diversity between individual cells and when comparing each of the cell types.

High-resolution sub-cellular imaging by correlative NanoSIMS and electron microscopy of amiodarone internalisation by lung macrophages as evidence for drug-induced phospholipidosis.

Correlative NanoSIMS and EM imaging of amiodarone-treated macrophages shows the internalisation of the drug at a sub-cellular level and reveals its accumulation within the lysosomes, providing direct evidence for amiodarone-induced phospholipidosis. Chemical fixation using tannic acid effectively seals cellular membranes aiding intracellular retention of diffusible drugs.

Semiempirical Rules To Determine Drug Sensitivity and Ionization Efficiency in Secondary Ion Mass Spectrometry Using a Model Tissue Sample.

There is an increasing need in the pharmaceutical industry to reduce drug failure at late stage and thus reduce the cost of developing a new medicine. Since most drug targets are intracellular, this requires a better understanding of the drug disposition within a cell. Secondary ion mass spectrometry has been identified as a potentially important technique to do this, as it is label-free and allows imaging in 3D with subcellular resolution and recent studies have shown promise for amiodarone.