Age-related Microglial Phenotype Characterized by Lipid and Iron Contents [July 5, 2023]

Scientists have unveiled that in comparison to young mice, one-third of old microglia show Lipofustin-related autofluorescence (AF), characterized by profound changes in lipid and iron content, phagocytic activity, and oxidative stress. Pharmacological removal of microglia in older mice successfully eliminated AF-microglia, following the repopulation of new functional microglia leads to an improvement in age-related neurological impairments and reduces neurodegeneration after traumatic brain injury. Learn more about how the authors phenotyped AF-microglia using Lipi-Blue* for Lipid droplet labeling, and FerroOrange* for iron labeling. (Please refer to Fig. 1E, 5F, 9E for FerrOrange, Fig. 5D, 7E, for Lipi-Blue)

Brain injury accelerates the onset of a reversible age-related microglial phenotype associated with inflammatory neurodegeneration
Click here for the original article: Rodney M Ritzel, et. al., Sci Adv (2023)

Point of Interest

- Lipofuscin accumulates in the brain's old microglia characterized by profound changes in lipid and iron content, phagocytosis, and oxidative stress.

- Increased phagocytic activity, lysosomal burden, and lipid accumulation in microglia are chronically driven by phagocyte-mediated oxidative stress.

- Pharmacological removal of lipofuscin-laden microglia in older mice leads to an improvement in age-related neurological impairments

Related Techniques

Lipid droplets detection

Lipi-Blue / Green / Red / Deep Red

Intracellular / mitochondrial ferrous ion (Fe²⁺) detection

FerroOrange(intracellular), Mito-FerroGreen(mitochondrial)

Cellular senescence detection

SPiDER-βGal for live-cell imaging or flow cytometry / microplate reader / tissue samples
SPiDER-βGal Blue for fixed cell and for multiple staining with immunostaining and other methods

Total ROS detection

Highly sensitive DCFH-DA or Photo-oxidation Resistant DCFH-DA

Mitochondrial superoxide detection

toBright ROS Deep Red - Mitochondrial Superoxide Detection

Related Applications

The simultaneous detection of lysosomal function with intracellular Fe2+

Recent reports suggest that lysosomal neutralization can result in iron depletion, consequently leading to the disruption of cell viability. To verify this, HeLa cells were labeled with FerroOrange for Fe²⁺ detection, and the lysosomal mass and pH were separately detected with LysoPrime DeepRed and pHLys Green (a product currently under development). Co-staining with FerroOrange and Lysosomal dyes demonstrated that Bafilomycin A1 (Baf. A1), an inhibitor of lysosomal acidification, causes iron depletion consistent with the findings reported in the article. Interestingly, the iron chelator, Deferiprone (DFP), did not impact lysosomal pH, suggesting that lysosomal function plays a key role in managing iron homeostasis.

Reference: Ross A Weber, et. al., Mol Cell (2020)

Products in Use
   - FerroOrange
   - pHLys Green*
   - LysoPrime Deep Red

*pHLys Green is available as the "Lysosomal Acidic pH Detection Kit-Green/Deep Red".