Mini202

Guide (The following is our recommended protocol. This protocol is for guidance only and should be modified according to your specific needs).

1. Stock Solution Preparation
1.1 Solvent: Not specified in the provided literature.
1.2 Concentration recommendation: 500 μM.

2. Working Solution Preparation
2.1 Diluent: Cell culture media.
2.2 Working concentration: 20 μM.
2.3 Note: Adjust working solution concentration as needed; prepare fresh before use.

3. Staining Procedure
3.1 Sample type descriptions
3.1.1 For adherent cultured cells (VMAT2-HEK cells, PC-12 cells)[1]: No trypsinization required prior to staining.
3.1.2 For suspension cells (primary perivascular adipose tissue adipocytes, differentiated perivascular adipose tissue adipocytes, adrenal medulla chromaffin cells)[2]: Centrifuge at 200×g for 5 minutes to pellet cells after digestion; centrifuge to wash cells post-incubation.
3.1.3 For primary adrenal chromaffin cells[3]: No pre-staining sample processing details provided.
3.2 Incubation conditions
3.2.1 For adherent cultured cells (VMAT2-HEK cells, PC-12 cells)[1]: Incubate VMAT2-HEK cells with 20 μM Mini202 for 30 min; incubate PC-12 cells with 20 μM Mini202 for 1 h.
3.2.2 For suspension cells (primary perivascular adipose tissue adipocytes, differentiated perivascular adipose tissue adipocytes, adrenal medulla chromaffin cells)[2]: Incubate with undiluted 500 μM Mini202 stock solution at 37°C for 60 minutes in the dark.
3.2.3 For primary adrenal chromaffin cells[3]: Uptake occurs via vesicular monoamine transporter 2 (VMAT2) into large dense core vesicles; no specific incubation time or concentration provided.
3.3 Washing steps
3.3.1 For adherent cultured cells (VMAT2-HEK cells, PC-12 cells)[1]: Rinse cells with dye-free media after incubation.
3.3.2 For suspension cells (primary perivascular adipose tissue adipocytes, differentiated perivascular adipose tissue adipocytes, adrenal medulla chromaffin cells)[2]: Wash 3 times with warm wash solution (4% BSA in KRBB) for adipocytes; wash 3 times with DMEM+10% FBS for adrenal medulla chromaffin cells.
3.3.3 For primary adrenal chromaffin cells[3]: Washing steps are omitted.

4. Controls
4.1 Negative control: Nontransfected HEK cells incubated with 20 μM Mini202[1].
4.2 Vehicle control: Cells incubated without Mini202[2].
4.3 Inhibitor controls:
4.3.1 VMAT2-HEK cells or PC-12 cells preincubated with 1 μM vesicular monoamine transporter inhibitor (or 1 μM vesicular monoamine transporter 2 inhibitor for VMAT2-HEK cells) before Mini202 incubation[1].
4.3.2 Cells preincubated with rose bengal, norepinephrine transporter inhibitor, or glucocorticoid prior to Mini202 addition[2].
4.4 Positive controls:
4.4.1 VMAT2-HEK cells or PC-12 cells incubated with 20 μM Mini202 without inhibitor pretreatment[1].
4.4.2 Adrenal medulla chromaffin cells incubated with Mini202 to validate the uptake system[2].

5. Detection & Analysis
5.1 Instrument type: Fluorescence microscopy, two-photon fluorescence microscopy, automated cell imaging system, total internal reflection fluorescence microscopy (TIRFM).
5.2 Ex/Em wavelengths
5.2.1 Single-photon fluorescence microscopy: Ex = 350 ± 25 nm, Em = 460 ± 25 nm[1].
5.2.2 Two-photon fluorescence microscopy: Ex = 760 nm or 692 nm, Em = 470 ± 30 nm[1].
5.2.3 Fluorescence microscope/automated cell imaging system: Detect in the DAPI channel[2].
5.3 Result analysis
5.3.1 Fluorescence localization: Punctate fluorescence in acidic secretory vesicles (LDCVs in PC-12 cells, VMAT2-positive organelles in HEK cells)[1]; blue fluorescence as a circle around the lipid droplet of adipocytes, brightest near the nucleus[2]; fluorescence localized to large dense core vesicles[3].
5.3.2 Fluorescence intensity changes: Ratiometric fluorescence intensity (I₇₆₀/I₆₉₂) correlates with vesicular pH; higher ratio corresponds to higher pH[1]; Mini202 uptake results in increased blue fluorescence signal; treatment with vesicular monoamine transporter, norepinephrine transporter, or organic cation transporter 3 inhibitors reduces fluorescence intensity[2]; fluorescence intensity decreases as the dye exits the vesicle and disperses to the extracellular solution upon stimulation[3].
5.3.3 Fluorescence color: Cyan fluorescence under single-photon excitation; red fluorescence at 760 nm two-photon excitation, green fluorescence at 692 nm two-photon excitation[1]; blue fluorescence is observed in cells with successful Mini202 uptake[2].
5.3.4 Control-specific results: No detectable fluorescence in cells preincubated with vesicular monoamine transporter inhibitor or vesicular monoamine transporter 2 inhibitor[1]; loss of punctate fluorescence, diffuse cytoplasmic fluorescence after lysosomotropic amine treatment[1].