HSPB1 Orchestrates the Inflammation-Associated Transcriptome Profile of Atherosclerosis in HUVECs.

Background: Atherosclerosis (AS), with a profound inflammatory response, is the basis of cardiovascular diseases. Previous reports showed that heat shock protein family B member 1 (HSPB1) has a protective effect against AS, but the specific mechanism is still unclear. In this study, we aim to explore the functions and downstream targets of HSPB1 in human umbilical vein endothelial cells (HUVECs).

Methods: Expression of the HSPB1 gene was knocked down in HUVECs. Cellular phenotype was then assessed and transcriptome data (RNA-seq) was analyzed to identify the potential targets regulated by HSPB1. Moreover, RNA-seq data for human fibroatheroma (GSE104140) from the gene expression omnibus (GEO) database was re-analyzed to verify the targets of HSPB1 in AS.

Results: Silencing of HSPB1 significantly reduced apoptosis (p < 0.0001) and increased the proliferation (p < 0.05) of HUVECs. The 608 differentially expressed genes (DEGs) were identified after HSPB1 knockdown, including 423 upregulated genes. DEGs, including CXCL1, CXCL8, CXCL2, TRIB3, GAS5, SELE, and TNIP1, were enriched in inflammatory and immune response pathways. HSPB1 was also shown to affect alternative splicing patterns of hundreds of genes, especially those enriched in apoptotic processes, including ACIN1, IFI27, PAK4, UBE2D3, and FIS1. An overlapping gene set was found between the HSPB1-regulated and AS-induced transcriptome. This included 171 DEGs and 250 alternatively spliced genes that were also enriched in inflammatory/immune response- and apoptosis-associated pathways, respectively.

Conclusion: In summary, HSPB1 knockdown modulates the proliferation and apoptosis of HUVECs by regulating RNA levels and alternative splicing patterns. HSPB1 plays an important role in AS pathogenesis by modulating the inflammatory and immune response. This study provides novel insights for the investigation of future AS therapeutic strategies.