Laser scanning microscopy showing comparison of vimentin and C-terminal specific perilipin antibodies using briefly AIM-stimulated human preadipocytes and detection of different perilipin staining-patterns.
(a) Pab Peri-hCT and mab Vim 3B4 reveal similar staining as seen with alike antibodies (cp. Fig. 6a). (b) At closer inspection, pab Peri-hCT often shows additional localization. Fine punctated rows of very small droplets can be seen on perinuclear distinct winded structures (perilipin staining pattern P1). (c) Enlarged perinuclear area of a cell starting adipocyte conversion. Many, tiny lipid droplets in the cytoplasm, can be seen especially at perinuclear structures (pattern P1) and in close association with the vimentin IF network. (d,d,d) Different stages of adipocyte conversion are present within the two neighboring cells shown. In the cell in the lower part of the pictures, conversion appears to begin, showing 2 different perilipin patterns - many tiny droplets binding in rows on winded perinuclear structures (pattern P1; cp. b,c) and plenty of small droplets with sizes estimated below 1 µm in diameter and distributed mainly above the perinuclear region in the cytoplasm (pattern P2). In the advanced conversion stage of the cell shown in the upper part of the picture, fairly well accomplished, bigger LDs are seen distributed all over the cytoplasm and surrounded by vimentin cages (pattern P3, examples of vimentin cages shown by arrowheads). Note, by increasing the time for AIM stimulation, we noticed an increased P3 pattern paralleled by decreasing P1 and P2 patterns. By conventionally longer AIM treatment (1–3 weeks), the P3 pattern could be seen almost exclusively in all differentiated cells. DAPI (blue). Bars in a-c: 20 µm. Bar in d: 10 µm;