Metagenomic Study Reveals Phage-Bacterial Interactome Dynamics in Gut and Oral Microbiota in Pancreatic Diseases.

Individuals with pancreatic-related health conditions usually show lower diversity and different composition of bacterial and viral species between the gut and oral microbiomes compared to healthy individuals. We performed a thorough microbiome analysis, using deep shotgun sequencing of stool and saliva samples obtained from patients with chronic pancreatitis (CP), pancreatic ductal adenocarcinoma (PDAC), and healthy controls (HCs).We observed similar microbiota composition at the species level in both the gut and oral samples in PDAC patients compared to HCs, among which the most distinctive finding was that the abundance of oral-originated Fusobacterium nucleatum species did not differ between the oral and the gut samples. Moreover, comparing PDAC patients with HCs, Klebsiella oxytoca was significantly more abundant in the stool samples of PDAC patients, while Streptococcus spp. showed higher abundance in both the oral and stool samples of PDAC patients. Finally, the most important finding was the distinctive gut phage-bacterial interactome pattern among PDAC patients. CrAssphages, particularly Blohavirus, showed mutual exclusion with K. oxytoca species, while Burzaovirus showed co-occurrence with Enterobacteriaceae spp., which have been shown to be capable of inducing DNA damage in human pancreatic cells ex vivo. The interactome findings warrant further mechanistic studies, as our findings may provide new insights into developing microbiota-based diagnostic and therapeutic methods for pancreatic diseases.

Corynoline protects chronic pancreatitis via binding to PSMA2 and alleviating pancreatic fibrosis.

BACKGROUND: Pancreatic fibrosis is the main pathological feature of chronic pancreatitis. There is a lack of medications that effectively alleviate or reverse pancreatic fibrosis and thus cure chronic pancreatitis. METHODS: We screened drugs that could alleviate pancreatic fibrosis from 80 traditional Chinese medicine monomers and verified their efficacy and mechanisms. RESULTS: We preliminarily identified corynoline as an antifibrotic candidate by drug screening among 80 compounds. In vitro, corynoline dose-dependently reduces collagen I synthesis in pancreatic stellate cells induced by TGF-ß1 and inhibits its activation. Furthermore, we found that corynoline could alleviate the morphological disruption, such as acinar cell atrophy, collagen deposition etc., as well as reduced pancreatic weight in mice with chronic pancreatitis. We further validated the antifibrotic effect of corynoline in mRNA and protein levels. We also found that corynoline could inhibit NF-κB signaling pathway in vitro and in vivo. Next, we identified PSMA2 as the binding protein of corynoline by Lip-SMap and validated it using DARTS. Moreover, the siRNA of PSMA2 disrupts the anti-fibrotic effect of corynoline. CONCLUSION: In conclusion, corynoline is a promising agent for the treatment of pancreatic fibrosis and chronic pancreatitis.

SEC16A Variants Predispose to Chronic Pancreatitis by Impairing ER-to-Golgi Transport and Inducing ER Stress.

Chronic pancreatitis (CP) is a complex disease with genetic and environmental factors at play. Through trio exome sequencing, a de novo SEC16A frameshift variant in a Chinese teenage CP patient is identified. Subsequent targeted next-generation sequencing of the SEC16A gene in 1,061 Chinese CP patients and 1,196 controls reveals a higher allele frequency of rare nonsynonymous SEC16A variants in patients (4.90% vs 2.93%; odds ratio [OR], 1.71; 95% confidence interval [CI], 1.26-2.33). Similar enrichments are noted in a French cohort (OR, 2.74; 95% CI, 1.67-4.50) and in a biobank meta-analysis (OR, 1.16; 95% CI, 1.04-1.31). Notably, Chinese CP patients with SEC16A variants exhibit a median onset age 5 years earlier than those without (40.0 vs 45.0; p = 0.012). Functional studies using three CRISPR/Cas9-edited HEK293T cell lines show that loss-of-function SEC16A variants disrupt coat protein complex II (COPII) formation, impede secretory protein vesicles trafficking, and induce endoplasmic reticulum (ER) stress due to protein overload. Sec16a+/- mice, which demonstrate impaired zymogen secretion and exacerbated ER stress compared to Sec16a+/+, are further generated. In cerulein-stimulated pancreatitis models, Sec16a+/- mice display heightened pancreatic inflammation and fibrosis compared to wild-type mice. These findings implicate a novel pathogenic mechanism predisposing to CP.

BET Inhibition Rescues Acinar-Ductal-Metaplasia and Ciliogenesis and Ameliorates Chronic Pancreatitis-Driven Changes in Mice With Loss of the Polarity Protein Par3.

BACKGROUND & AIMS: The apical-basal polarity of pancreatic acinar cells is essential for maintaining tissue architecture. However, the mechanisms by which polarity proteins regulate acinar pancreas injury and regeneration are poorly understood. METHODS: Cerulein-induced pancreatitis was induced in mice with conditional deletion of the polarity protein Par3 in the pancreas. The impact of Par3 loss on pancreas injury and regeneration was assessed by histologic analyses and transcriptional profiling by RNA sequencing. Mice were pretreated with the bromodomain and extraterminal domain (BET) inhibitor JQ1 before cotreatment with cerulein to determine the effect of BET inhibition on pancreas injury and regeneration. RESULTS: Initially, we show that Par3 is increased in acinar-ductal metaplasia (ADM) lesions present in human and mouse chronic pancreatitis specimens. Although Par3 loss disrupts tight junctions, Par3 is dispensable for pancreatogenesis. However, with aging, Par3 loss results in low-grade inflammation, acinar degeneration, and pancreatic lipomatosis. Par3 loss exacerbates acute pancreatitis-induced injury and chronic pancreatitis-induced acinar cell loss, promotes pancreatic lipomatosis, and prevents regeneration. Par3 loss also results in suppression of chronic pancreatitis-induced ADM and primary ciliogenesis. Notably, targeting BET proteins attenuates chronic pancreatitis-induced loss of primary cilia and promotes ADM in mice lacking pancreatic Par3. Targeting BET proteins also attenuates cerulein-induced acinar cell loss and enhances recovery of acinar cell mass and body weight of mice lacking pancreatic Par3. CONCLUSIONS: Combined, this study demonstrates how Par3 restrains chronic pancreatitis-induced changes in the pancreas and identifies a potential role for BET inhibitors to attenuate pancreas injury and facilitate regeneration.

Understanding Secondary Sarcopenia Development in Young Adults Using Pig Model with Chronic Pancreatitis.

Chronic pancreatitis (CP) in young individuals may lead to disease-related secondary sarcopenia (SSARC), characterized by muscle loss and systemic inflammation. In this study, CP was induced in young pigs, and serum levels of key hormones, muscle fiber diameters in various muscles, and the mRNA expression of genes related to oxidative stress and programmed cell death were assessed. A decrease in muscle fiber diameters was observed in SSARC pigs, particularly in the longissimus and diaphragm muscles. Hormonal analysis revealed alterations in dehydroepiandrosterone, testosterone, oxytocin, myostatin, and cortisol levels, indicating a distinct hormonal response in SSARC pigs compared to controls. Oxytocin levels in SSARC pigs were significantly lower and myostatin levels higher. Additionally, changes in the expression of catalase (CAT), caspase 8 (CASP8), B-cell lymphoma 2 (BCL2), and BCL2-associated X protein (BAX) mRNA suggested a downregulation of oxidative stress response and apoptosis regulation. A reduced BAX/BCL2 ratio in SSARC pigs implied potential caspase-independent cell death pathways. The findings highlight the complex interplay between hormonal changes and muscle degradation in SSARC, underscoring the need for further research into the apoptotic and inflammatory pathways involved in muscle changes due to chronic organ inflammation in young individuals.

Optimized rAAV8 targeting acinar KLF4 ameliorates fibrosis in chronic pancreatitis via exosomes-enriched let-7s suppressing pancreatic stellate cells activation.

Chronic pancreatitis (CP) is marked by progressive fibrosis and the activation of pancreatic stellate cells (PSCs), accompanied by the destruction of pancreatic parenchyma, leading to the loss of acinar cells (ACs). Few research studies have explored the mechanism by which damaged ACs (DACs) contribute to PSCs activation and pancreatic fibrosis. Currently, there are no effective drugs for curing CP or limiting the progression of pancreatic fibrosis. In this research, co-culture with intact acinar cells (IACs) suppressed PSC activation, while co-culture with DACs did the opposite. Krüppel-like factor 4 (KLF4) was significantly upregulated in DACs and was established as the key molecule that switches ACs from PSCs-suppressor to PSCs-activator. We revealed the exosomes of IACs contributed to the anti-activated function of IACs-CS on PSCs. MiRNome profiling showed that let-7 family is significantly enriched in IAC-derived exosomes (>30% miRNome), which partially mediates IACs' suppressive impacts on PSCs. Furthermore, it has been observed that the enrichment of let-7 in exosomes was influenced by the expression level of KLF4. Mechanistic studies demonstrated that KLF4 in ACs upregulated Lin28A, thereby decreasing let-7 levels in AC-derived exosomes, and thus promoting PSCs activation. We utilized an adeno-associated virus specifically targeting KLF4 in ACs (shKLF4-pAAV) to suppress PSCs activation in CP, resulting in reduced pancreatic fibrosis. IAC-derived exosomes hold potential as potent weapons against PSCs activation via let-7s, while activated KLF4/Lin28A signaling in DACs diminished such functions. ShKLF4-pAAV holds promise as a novel therapeutic approach for CP.

The Role of Twist1 in Chronic Pancreatitis-Associated Pancreatic Stellate Cells.

In healthy pancreas, pancreatic stellate cells (PaSCs) synthesize the basement membrane, which is mainly composed of type IV collagen and laminin. In chronic pancreatitis (CP), PaSCs are responsible for the production of a rigid extracellular matrix (ECM) that is mainly composed of fibronectin and type I/III collagen. Reactive oxygen species evoke the formation of the rigid ECM by PaSCs. One source of reactive oxygen species is NADPH oxidase (Nox) enzymes. Nox1 up-regulates the expression of Twist1 and matrix metalloproteinase-9 (MMP-9) in PaSCs from mice with CP. This study determined the functional relationship between Twist1 and MMP-9, and other PaSC-produced proteins, and the extent to which Twist1 regulates digestion of ECM proteins in CP. Twist1 induced the expression of MMP-9 in mouse PaSCs. The action of Twist1 was not selective to MMP-9 because Twist1 induced the expression of types I and IV collagen, fibronectin, transforming growth factor, and α-smooth muscle actin. Luciferase assay indicated that Twist1 in human primary PaSCs increased the expression of MMP-9 at the transcriptional level in an NF-κB dependent manner. The digestion of type I/III collagen by MMP-9 secreted by PaSCs from mice with CP depended on Twist1. Thus, Twist1 in PaSCs from mice with CP induced rigid ECM production and MMP-9 transcription in an NF-κB-dependent mechanism that selectively displayed proteolytic activity toward type I/III collagen.

Beta-cell function and glucose metabolism in patients with chronic pancreatitis.

AIMS: Chronic pancreatitis (CP) is - along with acute pancreatitis - the most frequent cause of diabetes of the exocrine pancreas (DEP). Although insulin deficiency is widely accepted as the major feature of DEP, it is still unclear whether diabetes associated with CP is characterized by additional or different functional defects of the insulin secretory machinery. To identify possible functional defects specifically induced by CP, we performed a cross-sectional study in individuals with normal glucose tolerance (NGT), impaired glucose tolerance (IGT) and diabetes mellitus (DM) comparing patients with and without CP (CP vs. NCP). METHODS: We administered an oral glucose tolerance test (OGTT) to all participants and, according to their glucose tolerance, classified them as NGT, IGT and DM. Insulin sensitivity and beta-cell functional parameters were derived from OGTT, hyperglycemic clamp and hyperinsulinemic euglycemic clamp. RESULTS: Studying 146 subjects, we found that beta-cell function and insulin secretion were significantly lower in CP compared to NCP patients. However, when we classified the subjects according to OGTT-derived glucose tolerance, we found no differences in beta-cell function or in insulin sensitivity between CP and NCP with the same glucose tolerance status. Of note, we found that arginine-stimulated insulin secretion is reduced only in subjects with CP and DM compared to NCP subjects with DM. CONCLUSIONS: Patients with CP had no specific alterations in insulin secretion and beta-cell function. However, in patients diagnosed with diabetes, we found a lower arginine-stimulated insulin secretion, a marker of reduced functional mass.

Heavy metals in cigarette smoke strongly inhibit pancreatic ductal function and promote development of chronic pancreatitis.

BACKGROUND AND AIMS: Smoking is recognised as an independent risk factor in the development of chronic pancreatitis (CP). Cystic fibrosis transmembrane conductance regulator (CFTR) function and ductal fluid and bicarbonate secretion are also known to be impaired in CP, so it is crucial to understand the relationships between smoking, pancreatic ductal function and the development of CP. METHODS: We measured sweat chloride (Cl-) concentrations in patients with and without CP, both smokers and non-smokers, to assess CFTR activity. Serum heavy metal levels and tissue cadmium concentrations were determined by mass spectrometry in smoking and non-smoking patients. Guinea pigs were exposed to cigarette smoke, and cigarette smoke extract (CSE) was prepared to characterise its effects on pancreatic HCO3 - and fluid secretion and CFTR function. We administered cerulein to both the smoking and non-smoking groups of mice to induce pancreatitis. RESULTS: Sweat samples from smokers, both with and without CP, exhibited elevated Cl- concentrations compared to those from non-smokers, indicating a decrease in CFTR activity due to smoking. Pancreatic tissues from smokers, regardless of CP status, displayed lower CFTR expression than those from non-smokers. Serum levels of cadmium and mercury, as well as pancreatic tissue cadmium, were increased in smokers. Smoking, CSE, cadmium, mercury and nicotine all hindered fluid and HCO3 - secretion and CFTR activity in pancreatic ductal cells. These effects were mediated by sustained increases in intracellular calcium ([Ca2+]i), depletion of intracellular ATP (ATPi) and mitochondrial membrane depolarisation. CONCLUSION: Smoking impairs pancreatic ductal function and contributes to the development of CP. Heavy metals, notably cadmium, play a significant role in the harmful effects of smoking. KEY POINTS: Smoking and cigarette smoke extract diminish pancreatic ductal fluid and HCO3 - secretion as well as the expression and function of CFTR Cd and Hg concentrations are significantly higher in the serum samples of smokers Cd accumulates in the pancreatic tissue of smokers.

Phase-changing citrate macromolecule combats oxidative pancreatic islet damage, enables islet engraftment and function in the omentum.

Clinical outcomes for total-pancreatectomy followed by intraportal islet autotransplantation (TP-IAT) to treat chronic pancreatitis (CP) are suboptimal due to pancreas inflammation, oxidative stress during islet isolation, and harsh engraftment conditions in the liver's vasculature. We describe a thermoresponsive, antioxidant macromolecule poly(polyethylene glycol citrate-co-N-isopropylacrylamide) (PPCN) to protect islet redox status and function and to enable extrahepatic omentum islet engraftment. PPCN solution transitions from a liquid to a hydrogel at body temperature. Islets entrapped in PPCN and exposed to oxidative stress remain functional and support long-term euglycemia, in contrast to islets entrapped in a plasma-thrombin biologic scaffold. In the nonhuman primate (NHP) omentum, PPCN is well-tolerated and mostly resorbed without fibrosis at 3 months after implantation. In NHPs, autologous omentum islet transplantation using PPCN restores normoglycemia with minimal exogenous insulin requirements for >100 days. This preclinical study supports TP-IAT with PPCN in patients with CP and highlights antioxidant properties as a mechanism for islet function preservation.

Brusatol alleviates pancreatic carcinogenesis via targeting NLRP3 in transgenic Krastm4Tyj Trp53tm1Brn Tg (Pdx1-cre/Esr1*) #Dam mice.

BACKGROUND: Pancreatic cancer (PanCa), ranked as the 4th leading cause of cancer-related death worldwide, exhibits an dismal 5-year survival rate of less than 5 %. Chronic pancreatitis (CP) is a known major risk factor for PanCa. Brusatol (BRT) possesses a wide range of biological functions, including the inhibition of PanCa proliferation. However, its efficacy in halting the progression from CP to pancreatic carcinogenesis remains unexplored. METHODS: We assess the effects of BRT against pancreatic carcinogenesis from CP using an experimentally induced CP model with cerulein, and further evaluate the therapeutic efficacy of BRT on PanCa by employing Krastm4TyjTrp53tm1BrnTg (Pdx1-cre/Esr1*) #Dam/J (KPC) mouse model. RESULTS: Our finding demonstrated that BRT mitigated the severity of cerulein-induced pancreatitis, reduced pancreatic fibrosis and decreased the expression of α-smooth muscle actin (α-SMA), which is a biomarker for pancreatic fibrosis. In addition, BRT exerted effects against cerulein-induced pancreatitis via inactivation of NLRP3 inflammasome. Moreover, BRT significantly inhibited tumor growth and impeded cancer progression. CONCLUSIONS: The observed effect of BRT on impeding pancreatic carcinogenesis through targeting NLRP3 inflammasome suggests its good potential as a potential agent for treatment of PanCa.

Modulation of Nuclear Receptor 4A1 Expression Improves Insulin Secretion in a Mouse Model of Chronic Pancreatitis.

OBJECTIVES: Diabetes secondary to chronic pancreatitis (CP) presents clinical challenges due to lack of understanding on factor(s) triggering insulin secretory defects. Therefore, we aimed to delineate the molecular mechanism of ß-cell dysfunction in CP. MATERIALS AND METHODS: Transcriptomic analysis was conducted to identify endocrine-specific receptor expression in mice and human CP on microarray. The identified receptor (NR4A1) was overexpressed in MIN6 cells using PEI linear transfection. RNA-Seq analysis of NR4A1-overexpressed (OE) MIN6 cells on NovaSeq6000 identified aberrant metabolic pathways. Upstream trigger for NR4A1OE was studied by InBio Discover and cytokine exposure, whereas downstream effect was examined by Fura2 AM-based fluorimetric and imaging studies. Mice with CP were treated with IFN-γ-neutralizing monoclonal antibodies to assess NR4A1 expression and insulin secretion. RESULTS: Increased expression of NR4A1 associated with decreased insulin secretion in islets (humans: controls 9 ± 0.2, CP 3.7 ± 0.2, mice: controls 8.5 ± 0.2, CP 2.1 ± 0.1 µg/L). NR4A1OE in MIN6 cells (13.2 ± 0.1) showed reduction in insulin secretion (13 ± 5 to 0.2 ± 0.1 µg/mg protein per minute, P = 0.001) and downregulation of calcium and cAMP signaling pathways. IFN-γ was identified as upstream signal for NR4A1OE in MIN6. Mice treated with IFN-γ-neutralizing antibodies showed decreased NR4A1 expression 3.4 ± 0.11-fold ( P = 0.03), showed improved insulin secretion (4.4 ± 0.2-fold, P = 0.01), and associated with increased Ca 2+ levels (2.39 ± 0.06-fold, P = 0.009). CONCLUSIONS: Modulating NR4A1 expression can be a promising therapeutic strategy to improve insulin secretion in CP.

Statin prevents cancer development in chronic inflammation by blocking interleukin 33 expression.

Chronic inflammation is a major cause of cancer worldwide. Interleukin 33 (IL-33) is a critical initiator of cancer-prone chronic inflammation; however, its induction mechanism by environmental causes of chronic inflammation is unknown. Herein, we demonstrate that Toll-like receptor (TLR)3/4-TBK1-IRF3 pathway activation links environmental insults to IL-33 induction in the skin and pancreas inflammation. An FDA-approved drug library screen identifies pitavastatin to effectively suppress IL-33 expression by blocking TBK1 membrane recruitment/activation through the mevalonate pathway inhibition. Accordingly, pitavastatin prevents chronic pancreatitis and its cancer sequela in an IL-33-dependent manner. The IRF3-IL-33 axis is highly active in chronic pancreatitis and its associated pancreatic cancer in humans. Interestingly, pitavastatin use correlates with a significantly reduced risk of chronic pancreatitis and pancreatic cancer in patients. Our findings demonstrate that blocking the TBK1-IRF3-IL-33 signaling axis suppresses cancer-prone chronic inflammation. Statins present a safe and effective prophylactic strategy to prevent chronic inflammation and its cancer sequela.

Clinical Significance of MUC4 and Associated Proteins in Pancreatic and Periampullary Cancers.

OBJECTIVE: This study primarily aimed to assess the expression of MUC4 in patients with pancreatic ductal adenocarcinoma (PDAC) as compared with controls and assess its clinical relevance. MATERIALS AND METHODS: Serum MUC4 levels and MUC4 gene expression in snap-frozen tissue were analyzed through surface plasmon resonance and quantitative polymerase chain reaction, respectively. Tumor tissues and control tissues were analyzed for MUC4 and other mucins through immunohistochemistry. RESULT: MUC4 expression in tumor tissue was found to be significantly elevated in PDAC patients as compared with chronic pancreatitis tissues and normal pancreatic tissues. Periampullary carcinoma and cholangiocarcinoma tissue also showed increased expression of MUC4 and other mucins. CONCLUSIONS: Differential expression of MUC4 in pancreatic tumor tissues can help to differentiate PDAC from benign conditions.

Chronic pancreatitis-associated metabolic bone diseases: epidemiology, mechanisms, and clinical advances.

Chronic pancreatitis (CP) is a progressive inflammatory disease with an increasing global prevalence. In recent years, a strong association between CP and metabolic bone diseases (MBDs), especially osteoporosis, has been identified, attracting significant attention in the research field. Epidemiological data suggest a rising trend in the incidence of MBDs among CP patients. Notably, recent studies have highlighted a profound interplay between CP and altered nutritional and immune profiles, offering insights into its linkage with MBDs. At the molecular level, CP introduces a series of biochemical disturbances that compromise bone homeostasis. One critical observation is the disrupted metabolism of vitamin D and vitamin K, both essential micronutrients for maintaining bone integrity, in CP patients. In this review, we provide physio-pathological perspectives on the development and mechanisms of CP-related MBDs. We also outline some of the latest therapeutic strategies for treating patients with CP-associated MBDs, including stem cell transplantation, monoclonal antibodies, and probiotic therapy. In summary, CP-associated MBDs represent a rising medical challenge, involving multiple tissues and organs, complex disease mechanisms, and diverse treatment approaches. More in-depth studies are required to understand the complex interplay between CP and MBDs to facilitate the development of more specific and effective therapeutic approaches.

Activin A signaling stimulates neutrophil activation and macrophage migration in pancreatitis.

Acute Pancreatitis (AP) is associated with high mortality and current treatment options are limited to supportive care. We found that blockade of activin A (activin) in mice improves outcomes in two murine models of AP. To test the hypothesis that activin is produced early in response to pancreatitis and is maintained throughout disease progression to stimulate immune cells, we first performed digital spatial profiling (DSP) of human chronic pancreatitis (CP) patient tissue. Then, transwell migration assays using RAW264.7 mouse macrophages and qPCR analysis of "neutrophil-like" HL-60 cells were used for functional correlation. Immunofluorescence and western blots on cerulein-induced pancreatitis samples from pancreatic acinar cell-specific Kras knock-in (Ptf1aCreER™; LSL-KrasG12D) and functional WT Ptf1aCreER™ mouse lines mimicking AP and CP to allow for in vivo confirmation. Our data suggest activin promotes neutrophil and macrophage activation both in situ and in vitro, while pancreatic activin production is increased as early as 1 h in response to pancreatitis and is maintained throughout CP in vivo. Taken together, activin is produced early in response to pancreatitis and is maintained throughout disease progression to promote neutrophil and macrophage activation.

Differences in Plasma Fatty Acid Composition Related to Chronic Pancreatitis: A Pilot Study.

OBJECTIVES: Chronic pancreatitis (CP) is an inflammatory disease affecting the absorption of fat-soluble nutrients. Signaling in pancreatic cells that lead to inflammation may be influenced by fatty acids (FAs) through diet and de novo lipogenesis. Here, we investigated the relationship between plasma FA composition in CP with heterogeneity of etiology and complications of CP. MATERIALS AND METHODS: Blood and clinical parameters were collected from subjects with CP (n = 47) and controls (n = 22). Plasma was analyzed for FA composition using gas chromatography and compared between controls and CP and within CP. RESULTS: Palmitic acid increased, and linoleic acid decreased in CP compared with controls. Correlations between age or body mass index and FAs are altered in CP compared with controls. Diabetes, pancreatic calcifications, and substance usage, but not exocrine pancreatic dysfunction, were associated with differences in oleic acid and linoleic acid relative abundance in CP. De novo lipogenesis index was increased in the plasma of subjects with CP compared with controls and in calcific CP compared with noncalcific CP. CONCLUSIONS: Fatty acids that are markers of de novo lipogenesis and linoleic acid are dysregulated in CP depending on the etiology or complication. These results enhance our understanding of CP and highlight potential pathways targeting FAs for treating CP.

COMP promotes pancreatic fibrosis by activating pancreatic stellate cells through CD36-ERK/AKT signaling pathways.

BACKGROUND: Pancreatic fibrosis is one of the most important pathological features of chronic pancreatitis (CP) and pancreatic stellate cells (PSCs) are the key cells of fibrosis. As an extracellular matrix (ECM) glycoprotein, cartilage oligomeric matrix protein (COMP) is critical for collagen assembly and ECM stability and recent studies showed that COMP exert promoting fibrosis effect in the skin, lungs and liver. However, the role of COMP in activation of PSCs and pancreatic fibrosis remain unclear. We aimed to investigate the role and specific mechanisms of COMP in regulating the profibrotic phenotype of PSCs and pancreatic fibrosis. METHODS: ELISA method was used to determine serum COMP in patients with CP. Mice model of CP was established by repeated intraperitoneal injection of cerulein and pancreatic fibrosis was evaluated by Hematoxylin-Eosin staining (H&E) and Sirius red staining. Immunohistochemical staining was used to detect the expression changes of COMP and fibrosis marker such as α-SMA and Fibronectin in pancreatic tissue of mice. Cell Counting Kit-8, Wound Healing and Transwell assessed the proliferation and migration of human pancreatic stellate cells (HPSCs). Western blotting, qRT-PCR and immunofluorescence staining were performed to detect the expression of fibrosis marker, AKT and MAPK family proteins in HPSCs. RNA-seq omics analysis as well as small interfering RNA of COMP, recombinant human COMP (rCOMP), MEK inhibitors and PI3K inhibitors were used to study the effect and mechanism of COMP on activation of HPSCs. RESULTS: ELISA showed that the expression of COMP significantly increased in the serum of CP patients. H&E and Sirius red staining analysis showed that there was a large amount of collagen deposition in the mice in the CP model group and high expression of COMP, α-SMA, Fibronectin and Vimentin were observed in fibrotic tissues. TGF-ß1 stimulates the activation of HPSCs and increases the expression of COMP. Knockdown of COMP inhibited proliferation and migration of HPSCs. Further, RNA-seq omics analysis and validation experiments in vitro showed that rCOMP could significantly promote the proliferation and activation of HPSCs, which may be due to promoting the phosphorylation of ERK and AKT through membrane protein receptor CD36. rCOMP simultaneously increased the expression of α-SMA, Fibronectin and Collagen I in HPSCs. CONCLUSION: In conclusion, this study showed that COMP was up-regulated in CP fibrotic tissues and COMP induced the activation, proliferation and migration of PSCs through the CD36-ERK/AKT signaling pathway. COMP may be a potential therapeutic candidate for the treatment of CP. Interfering with the expression of COMP or the communication between COMP and CD36 on PSCs may be the next direction for therapeutic research.

Retinoic acid signaling pathway in pancreatic stellate cells: Insight into the anti-fibrotic effect and mechanism.

Pancreatic stellate cells (PSCs) are activated following loss of cytoplasmic vitamin A (retinol)-containing lipid droplets, which is a key event in the process of fibrogenesis of chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDCA). PSCs are the major source of cancer-associated fibroblasts (CAFs) that produce stroma to induce PDAC cancer cell growth, invasion, and metastasis. As an active metabolite of retinol, retinoic acid (RA) can regulate target gene expression in PSCs through its nuclear receptor complex (RAR/RXR or RXR/RXR) or transcriptional intermediary factor. Additionally, RA also has extranuclear and non-transcriptional effects. In vitro studies have shown that RA induces PSC deactivation which reduces extracellular matrix production through multiple modes of action, such as inhibiting TßRⅡ, PDGFRß, ß-catenin and Wnt production, downregulating ERK1/2 and JNK phosphorylation and suppressing active TGF-ß1 release. RA alone or in combination with other reagents have been demonstrated to have an effective anti-fibrotic effect on cerulein-induced mouse CP models in vivo studies. Clinical trial data have shown that repurposing all-trans retinoic acid (ATRA) as a stromal-targeting agent for human pancreatic cancer is safe and tolerable, suggesting the possibility of using RA for the treatment of CP and PDCA in humans. This review focuses on RA signaling pathways in PSCs and the effects and mechanisms of RA in PSC-mediated fibrogenesis as well as the anti-fibrotic and anti-tumor effects of RA targeting PSCs or CAFs in vitro and in vivo, highlighting the potential therapies of RA against CP and PDAC.