HMG Box-Containing Protein 1 (HBP1) Protects Against Pancreatic Injury in Acute Pancreatitis but Promotes Neoplastic Progression

Background & Aims Pancreatitis is an inflammatory disease of the exocrine pancreas and a known risk factor for pancreatic ductal adenocarcinoma (PDAC). Previously, we identified HMG- box transcription factor 1 (HBP1) as a potential master transcription factor (TF) in the early progression of PDAC, with its expression associated with poor patient survival, underscoring its significance in pancreatic disease. However, the functional role of HBP1 in the onset and progression of acute pancreatitis (AP) remains unknown. Methods We examined HBP1 expression in human pancreatitis samples and a cerulein-induced AP mouse model. Pancreatic-specific conditional HBP1 knockout mice, with or without an oncogenic Kras mutation, were generated and compared to their littermate controls. Spatial transcriptomics and multiplexed protein assays, histological analysis, and immunostaining were utilized to characterize pathological changes. Findings from mouse models were validated using inducible HBP1-overexpressing human pancreatic ductal epithelial cells. Results HBP1 was upregulated in pancreatic exocrine cells in human chronic pancreatitis and mouse acute pancreatitis, with its expression in human chronic pancreatitis correlating with cancer presence. Pancreatic HBP1 ablation disrupted acinar homeostasis by impairing autophagic flux and exacerbating inflammation following injury. In the presence of oncogenic KRAS, HBP1 ablation delayed the formation of pancreatic intraepithelial neoplasia (PanIN), the precursor to PDAC, and slowed its progression to higher-grade lesions. Conclusions HBP1 upregulation in pancreatitis mitigates pancreatic inflammatory injury; however, in the presence of oncogenic KRAS, it facilitates PanIN progression. Thus, HBP1 serves as a critical regulator in both pancreatitis and early pancreatic neoplasia, representing a potential therapeutic target for intervening pancreatitis and PanIN progression. Spatial transcriptomic analysis was performed on pancreata from three HBP1 WT and three HBP1 CKO mice on days 1 and 2 post-cerulein treatment. Pancreatitis areas were mounted on 10x Genomics Visium slides, with 5000 barcoded 55 µm spots capturing 1–10 cells per spot, each containing millions of probes for 20,551 mouse genes via CytAssist28. Sequencing (25k read pairs/spot) generated FASTQ files, which were mapped to H&E images and feature-barcode matrices using Spaceranger.