Related Experiment Video
Updated: Sep 28, 2025
Imaging Analysis of Neuron to Glia Interaction in Microfluidic Culture Platform MCP-based Neuronal Axon and Glia Co-culture System
Published on: October 14, 2012
Microglia-Specific Promoter Activities of HEXB Gene
Sahil Shah1,2, Lilly M Wong3, Kendra Ellis1,2
1Center for Metabolic Disease Research, Temple University Lewis Katz School of Medicine, Philadelphia, PA, United States.
Abstract:
Adeno-associated virus (AAV)-mediated genetic targeting of microglia remains a challenge. Overcoming this hurdle is essential for gene editing in the central nervous system (CNS). Here, we characterized the minimal/native promoter of the HEXB gene, which is known to be specifically and stably expressed in the microglia during homeostatic and pathological conditions. Dual reporter and serial deletion assays identified the critical role of the natural 5' untranslated region (-97 bp related to the first ATG) in driving transcriptional activity of the mouse Hexb gene. The native promoter region of mouse, human, and monkey HEXB are located at -135, -134, and -170 bp to the first ATG, respectively. These promoters were highly active and specific in microglia with strong cross-species transcriptional activities, but did not exhibit activity in primary astrocytes. In addition, we identified a 135 bp promoter of CD68 gene that was highly active in microglia but not in astrocytes. Considering that HEXB is specifically expressed in microglia, these data suggest that the newly characterized microglia-specific HEXB minimal/native promoter can be an ideal candidate for microglia-targeting AAV gene therapy in the CNS.
Insights
Researchers identified novel microglia-specific promoters from the HEXB gene. These promoters show cross-species activity and are ideal for adeno-associated virus (AAV) gene therapy in the central nervous system (CNS).
Area of Science:
- Neuroscience
- Molecular Biology
- Gene Therapy
Background:
- Targeting microglia in the central nervous system (CNS) using adeno-associated virus (AAV) vectors is challenging.
- Microglia play crucial roles in CNS homeostasis and pathology, making them key targets for gene therapy.
Purpose of the Study:
- To identify and characterize novel microglia-specific promoters for AAV-mediated gene delivery.
- To evaluate the transcriptional activity and specificity of these promoters in microglia.
Main Methods:
- Dual reporter and serial deletion assays were used to characterize the minimal/native promoter of the HEXB gene.
- Promoter activity was assessed in primary microglia and astrocytes across different species (mouse, human, monkey).
- The CD68 gene promoter was also identified and characterized.
Main Results:
- The 5' untranslated region (-97 bp) of the mouse Hexb gene was identified as critical for transcriptional activity.
- Native HEXB promoter regions (-135 bp in mouse, -134 bp in human, -170 bp in monkey) demonstrated high activity and specificity in microglia.
- These HEXB promoters showed cross-species activity and no activity in astrocytes.
- A 135 bp CD68 promoter was also found to be microglia-specific.
Conclusions:
- The newly characterized HEXB minimal/native promoter is a potent and specific tool for microglia targeting.
- This promoter is a promising candidate for developing microglia-specific AAV gene therapy strategies in the CNS.
- The findings advance the potential for precise genetic manipulation of microglia in neurological diseases.
