Related Experiment Video
Updated: Nov 9, 2025
A Mouse Model for Chronic Pancreatitis via Bile Duct TNBS Infusion
Published on: February 28, 2021
Inhibitory Smads suppress pancreatic stellate cell activation through negative feedback in chronic pancreatitis
Hao Lin1,2, Beibei Dong3, Liang Qi3
1Department of Clinical Science and Research, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, China.
Background:
Activation of pancreatic stellate cells (PSCs) is a key cause of chronic pancreatitis (CP), while inhibition of transforming growth factor-β (TGF-β) signaling renders PSCs inactive. Inhibitory Smads (I-Smads) impede TGF-β intracellular signaling and may provide a way to alleviate CP. Thus, we aimed to investigate the molecular mechanism of I-Smads in CP animals and freshly-isolated PSCs.
Methods:
Sixteen male C57BL/6 mice were randomly divided into two groups; a control group (treated with saline) and a CP group (treated with caerulein) for 6 weeks. Masson's staining was performed to identify fibrosis, and immunohistochemistry (IHC) was performed to measure the levels of Smad6 between the two groups. An improved method derived from internal digestion was used to isolate PSCs from male Sprague Dawley rats. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunofluorescence staining were used to measure the messenger ribonucleic acid (mRNA) and protein levels of alpha-smooth muscle actin (α-SMA). Plasmids of I-Smads or SB431542 were transfected into freshly-isolated PSCs, and relative mRNA levels of marker genes were quantified by qRT-PCR. The two-tailed Student's t-test was performed to assess significance.
Results:
The Smad6 protein level was significantly higher in the pancreas tissue of CP mice compared to the control group. A large number of PSCs were isolated from rat pancreas using an improved isolating method and were confirmed by quiescent and active PSC markers including cluster differentiation antigen 133 (CD133), perilipin 2 (Plin2), α-SMA, Desmin, and collagen 1 (Col1). The mRNA levels of both Smad6 and Smad7 were down-regulated during freshly-isolated PSC activation. Over-expression of both Smad6 and Smad7 in freshly-isolated PSC reduced the mRNA level of α-SMA, glial fibrillary acidic protein (GFAP), Desmin, Col1, Col3, and fibronectin 1 (Fn1) significantly. SB431542 reduced the mRNA level of α-SMA, Col1, Col3, and Fn1 significantly in freshly-isolated PSCs.
Conclusions:
This study demonstrated that CP promoted the expression of I-Smads, which suppressed the activation of freshly-isolated PSCs via a negative feedback loop.
Insights
In chronic pancreatitis (CP), inhibitory Smads (I-Smads) are upregulated and suppress pancreatic stellate cell (PSC) activation. This suggests I-Smads may be a therapeutic target for CP.
Area of Science:
- Gastroenterology
- Cell Biology
- Molecular Medicine
Background:
- Pancreatic stellate cell (PSC) activation drives chronic pancreatitis (CP).
- Transforming growth factor-β (TGF-β) signaling inhibition inactivates PSCs.
- Inhibitory Smads (I-Smads) block TGF-β signaling and may treat CP.
Purpose of the Study:
- Investigate the molecular mechanism of I-Smads in CP.
- Determine the role of I-Smads in PSC activation and CP progression.
Main Methods:
- Compared Smad6 levels in CP and control mice using immunohistochemistry.
- Isolated and characterized PSCs from rats.
- Analyzed I-Smad and α-SMA expression via qRT-PCR and immunofluorescence.
- Manipulated I-Smad and TGF-β signaling in PSCs using plasmids and SB431542.
Main Results:
- CP mice showed higher Smad6 levels than controls.
- Isolated PSCs expressed activation markers (α-SMA, Desmin, Col1).
- I-Smad (Smad6, Smad7) mRNA levels decreased during PSC activation.
- Overexpressing I-Smads reduced PSC activation markers and fibrosis-related genes.
- SB431542 inhibited PSC activation markers and fibrosis-related genes.
Conclusions:
- CP upregulates I-Smads in pancreatic tissue.
- I-Smads suppress freshly-isolated PSC activation through a negative feedback loop.
- I-Smads represent a potential therapeutic target for CP.
Related Concept Videos
01:24Chronic Pancreatitis I: Introduction
Pancreatitis is the inflammation of the pancreas, which occurs when the immune system becomes active and causes swelling, pain, and disruptions in organ function. Pancreatitis can manifest as either an acute or chronic condition.
Acute pancreatitis arises suddenly and lasts for a brief duration, while chronic pancreatitis is a long-term affliction...
01:29Chronic Pancreatitis II: Collaborative Care
Assessment:
01:16TGF - β Signaling Pathway
01:20The JAK-STAT Signaling Pathway
01:12Role Of Notch Signalling In Intestinal Stem Cell Renewal
Direct cell-to-cell contact is needed for the activation of Notch signaling. The signal is initiated when a notch ligand binds to a receptor on an adjacent cell, also...
01:27Glucose Homeostasis: Pancreatic Islets and Insulin Secretion
Insulin and C-peptide are...