Fig. 6: Endocytosis in WT and Trpml3^−/− AMΦ.

a Shown are representative confocal images obtained from endocytosis experiments using dextran coupled to Alexa Fluor 568. Images show AMΦ (WT vs. Trpml3^−/−) that have been pulsed with fluorescently labelled dextran for different time periods. Scale bar 5 µm. b Quantification of dextran uptake showing significantly decreased rates of endocytosis in Trpml3^−/− AMΦ compared to WT AMΦ at various time points. A sum of at least 130 cells were analysed per timepoint and genotype deriving from five biologically independent experiments for both Trpml3^−/− lines (Mcoln3^tm1.2Hels and Mcoln3^tm1.1Jga), respectively. Data are mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001; Two-way ANOVA followed by Bonferroni’s post hoc test. c Effect of different endocytosis inhibitors on MMP-12 levels in WT and Trpml3^−/− AMΦ supernatants (SN). *p < 0.05, **p < 0.01, ****p < 0.0001; One-way ANOVA followed by Dunnett’s post hoc test. One single dot corresponds to the AMΦ SN from one well, each. 11 WT and 11 Trpml3^−/− mice were lavaged to obtain the number of cells for all wells. Data are mean ± SEM. d Cartoon showing endocytosis of MMP-12 via three different endocytosis pathways (CME, CIE, MP) and the effect of endocytosis inhibitors on MMP-12 uptake: According to the results shown in (c) the MMP-12 uptake in AMΦ corresponds to CIE and MP, resulting in higher concentrations of MMP-12 in the extracellular fluid after inhibition of these pathways. CME seems to be not involved. e Effect of the selective TRPML3 agonist ML3-SA1 (incubation o.n., 30 µM) on MMP-12 levels in WT and Trpml3^−/− AMΦ supernatants (SN). *p < 0.05, Student’s t test, unpaired, two-tailed. One single dot corresponds to the AMΦ SN from one well, each. 5 WT and 5 Trpml3^−/− mice were lavaged to obtain the appropriate number of cells for all wells. Data are mean ± SEM. Source data are provided as a Source Data file.