Differential kinetics of plasma CD105 and transforming growth factor beta expression early in human acute pancreatitis

TGFβ and Hippo Signaling Pathways Coordinate to Promote Acinar to Ductal Metaplasia in Human Pancreas

BACKGROUND & AIMS

Acinar-to-ductal metaplasia (ADM) serves as a precursor event in the development of pancreatic ductal adenocarcinoma (PDAC) upon constitutive environmental and genetical stress. While the role of ADM in PDAC progression has been established, the molecular mechanisms underlying human ADM remain elusive. We previously demonstrated the induction of ADM in human acinar cells through the transforming growth factor beta (TGFβ) signaling pathway. We aim to investigate the interaction between TGFβ and Hippo pathways in mediating ADM.

METHODS

RNA-sequencing was conducted on sorted normal primary human acinar, ductal, and AD (acinar cells that have undergone ADM) cells. ATAC-seq analysis was utilized to reveal the chromatin accessibility in these three cell types. ChIP-Seq of YAP1, SMAD4, and H3K27ac was performed to identify the gene targets of YAP1 and SMAD4. The role of YAP1/TAZ in ADM-driven cell proliferation, as well as in oncogenic KRAS driven proliferation, was assessed using sphere formation assay.

RESULTS

AD cells have a unique transcription profile, with upregulated genes in open chromatin states in acinar cells. YAP1 and SMAD4 co-occupy the loci of ADM-related genes, including PROM1, HES1, and MMP7, co-regulating biological functions such as cell adhesion, cell migration, and inflammation. Overexpression of YAP1/TAZ promoted acinar cell proliferation but still required the TGFβ pathway. YAP1/TAZ were also crucial for TGFβ-induced sphere formation and were necessary for KRAS-induced proliferation.

CONCLUSIONS

Our study reveals the intricate transition between acinar and AD states in human pancreatic tissues. It unveils the complex interaction between the Hippo and TGF-β pathways during ADM, highlighting the pivotal role of YAP1/TAZ and SMAD4 in PDAC initiation.

Fire in the belly: A scoping review of the immunopathological mechanisms of acute pancreatitis

Introduction

Acute pancreatitis (AP) is characterised by an inflammatory response that in its most severe form can cause a systemic dysregulated immune response and progression to acute multi-organ dysfunction. The pathobiology of the disease is unclear and as a result no targeted, disease-modifying therapies exist. We performed a scoping review of data pertaining to the human immunology of AP to summarise the current field and to identify future research opportunities.

Methods

A scoping review of all clinical studies of AP immunology was performed across multiple databases. Studies were included if they were human studies of AP with an immunological outcome or intervention.

Results

205 studies met the inclusion criteria for the review. Severe AP is characterised by significant immune dysregulation compared to the milder form of the disease. Broadly, this immune dysfunction was categorised into: innate immune responses (including profound release of damage-associated molecular patterns and heightened activity of pattern recognition receptors), cytokine profile dysregulation (particularly IL-1, 6, 10 and TNF-α), lymphocyte abnormalities, paradoxical immunosuppression (including HLA-DR suppression and increased co-inhibitory molecule expression), and failure of the intestinal barrier function. Studies including interventions were also included. Several limitations in the existing literature have been identified; consolidation and consistency across studies is required if progress is to be made in our understanding of this disease.

Conclusions

AP, particularly the more severe spectrum of the disease, is characterised by a multifaceted immune response that drives tissue injury and contributes to the associated morbidity and mortality. Significant work is required to develop our understanding of the immunopathology of this disease if disease-modifying therapies are to be established.

Transforming growth factor-β in pancreatic diseases: Mechanisms and therapeutic potential

Pancreatic diseases, such as acute pancreatitis, chronic pancreatitis, and pancreatic cancer, are common gastrointestinal diseases resulting in the development of local and systemic complications with a high risk of death. Numerous studies have examined pancreatic diseases over the past few decades; however, the pathogenesis remains unclear, and there is a lack of effective treatment options. Recently, emerging evidence has suggested that transforming growth factor beta (TGF-β) exerts controversial functions in apoptosis, inflammatory responses, and carcinogenesis, indicating its complex role in the pathogenesis of pancreas-associated disease. Therefore, a further understanding of relevant TGF-β signalling will provide new ideas and potential therapeutic targets for preventing disease progression. This is the first systematic review of recent data from animal and human clinical studies focusing on TGF-β signalling in pancreas damage and diseases. This information may aid in the development of therapeutic agents for regulating TGF-β in this pathology to prevent or treat pancreatic diseases.

The immune imbalance in the second hit of pancreatitis is independent of IL-17A

BACKGROUND

Severe acute pancreatitis (SAP) is characterised by two distinct clinical phases. Organ dysfunction and death is initially as a result of a systemic inflammatory response syndrome (SIRS). Systemic sepsis from infected pancreatic necrosis characterises the second phase, the so called 'second hit' of acute pancreatitis (AP). An immune imbalance during the second hit is postulated to contribute to the formation of the septic complications that occur in these patients. The pro-inflammatory T-helper (Th) 17 pathway has been shown to be an initiator of early SIRS in AP, however to date its role has not been established in the second hit in AP.

METHODS

Thirty-six patients with mild (n = 16), moderate (n = 10) and severe (n = 10) acute pancreatitis were enrolled. Peripheral blood samples were drawn on days 7, 9, 11 and 13 of illness for analysis of routine clinical markers as well as cytokine analysis. Flow cytometry and a IL-17A ELISA was performed to determine cytokine concentrations.

RESULTS

There were no significant differences between days 7, 9, 11 and 13 for either the mild/moderate or SAP groups for IL-17A (CBA assay or ELISA), IFN-γ, TNF-α, IL-2 or IL-4. For each of the study days, the mean IL-6 and IL-10 concentrations were significantly higher in the SAP group compared to the mild/moderate group. WCC, CRP and PCT were all significantly higher in severe acute pancreatitis over the study days.

CONCLUSIONS

An immune imbalance exists in patients with SAP, however secreted IL-17A is not responsible for the second hit in AP.

Potential Prediction of Acute Biliary Pancreatitis Outcome on Admission

OBJECTIVES

This pilot study aimed to determine the feasibility of serum values of osteonectin, adiponectin, transforming growth factor beta 1, and neurotensin being used in clinical practice to predict the severity of acute pancreatitis.

METHODS

Blood samples were collected from 45 consecutive newly diagnosed acute pancreatitis patients and 30 matched healthy controls. The 2 groups were matched according to age, sex, weight, height, diabetes, smoking, and alcohol consumption. The aforementioned markers were measured using enzyme-linked immunosorbent assay kits.

RESULTS

Characteristics of acute pancreatitis patients and healthy controls were comparable. Osteonectin values differed significantly (P < 0.0001). Median/lower quartile/upper quartile of osteonectin levels for acute pancreatitis patients and healthy controls were 263.5/110.3/490.36 and 63.2/46.1/87.2 ng/mL, respectively. Two patients died, 1 patient underwent necrosectomy, and 4 patients had a prolonged intensive care unit/hospital stay. Acute Physiology and Chronic Health Evaluation II and Systemic Inflammatory Response Syndrome scores neither predicted serum values of any of the measured substances nor the clinical outcome (need for intervention, prolonged intensive care unit/hospital stay and mortality). Osteonectin was the only independent predictor for clinical outcome (P = 0.007).

CONCLUSIONS

Serum osteonectin strongly discriminates healthy individuals from acute pancreatitis patients. Serum osteonectin shows promise in the prediction of the clinical outcome.