Heparanase Modulates Chromatin Accessibility.

Area of Science:

• Molecular Biology
• Epigenetics
• Biochemistry

Background:

• Heparanase is the primary enzyme responsible for degrading heparan sulfate in the cell surface and extracellular matrix.
• The nuclear localization of heparanase suggests a role beyond ECM degradation, but its function remains unclear.

Purpose of the Study:

• To investigate the functional role of nuclear heparanase in regulating chromatin accessibility and gene expression.
• To elucidate the molecular mechanisms underlying the reduced inflammatory responses and tumor growth observed in heparanase-deficient models.

Main Methods:

• Utilized transposase-accessible chromatin with sequencing (ATAC-seq) on mouse embryonic fibroblasts (MEFs) from heparanase knockout (Hpse-KO) and wild-type (WT) mice.
• Integrated ATAC-seq data with genome-wide analysis of chromatin states.
• Performed Western blot analysis to assess histone modifications, specifically H3K27ac, in MEFs and tissues.

Main Results:

• Heparanase deficiency (Hpse-KO) significantly impacts chromatin accessibility, particularly in enhancer and promoter regions.
• Hpse-KO MEFs exhibited reduced activity in enhancer and promoter regions compared to WT MEFs.
• Western blot analysis confirmed a decrease in H3K27ac expression in Hpse-KO mice, indicating altered epigenetic regulation.

Conclusions:

• Heparanase plays a crucial role in regulating chromatin accessibility and epigenetic modifications, including H3K27 acetylation.
• These findings provide a mechanistic basis for the observed attenuation of inflammatory responses and tumor growth in heparanase knockout mice.
• The nuclear function of heparanase is linked to epigenetic regulation, impacting key cellular processes.