Physiological and clinically attainable concentrations of 1,25-dihydroxyvitamin D3 suppress proliferation and extracellular matrix protein expression in mouse pancreatic stellate cells

Vitamin D3 analogue calcipotriol inhibits the profibrotic effects of transforming growth factor- β1 on pancreatic stellate cells

OBJECTIVE

To evaluate the inhibitory effect of vitamin D3 analogue calcipotriol (Cal) on the fibrosis of pancreatic stellate cells (PSCs) induced by TGF-β1 and the rationality of Cal use in alcoholic chronic pancreatitis (ACP).

MATERIAL AND METHODS

Double-labeling immunofluorescence was used for the identification of VDR+PSCs in the pancreas of healthy controls (HC) and ACP patients. Van Gieson staining for examination of collagen fibers. RT-qPCR and Western Blot for determining the mRNAs and proteins of VDR, TGF-β1 and COL1A1 in the pancreas of ACP or in vitro PSCs. ELISA or LC-MS/MS for detection of serum TGF-β1 and COL1A1 or 25(OH)D3. The PSC line (RP-2 cell) was used for the determination of proteomic alterations in Cal plus TGF-β1 versus TGF-β1 and to examine the effect of VDR gene knockdown.

RESULTS

Enhanced expression of VDR was detected in RP-2 cells stimulated with alcohol (ALC) plus Cal versus Cal alone and in PSCs in the pancreas of ACP versus HC. The increased VDR+PSCs were positively correlated with the levels of COL1A1 mRNAs or areas of collagen deposition in the pancreas of ACP. TGF-β1 was overexpressed in the pancreas of ACP and ALC-treated RP-2 cells while 25(OH)D3 level in serum was significantly decreased in ACP versus HC. Through a VDR-dependent mechanism, Cal antagonized 16 profibrotic proteins in TGF-β1-induced RP-2 cells that included 7 extracellular matrix components, 2 cytoskeletal proteins, 2 fibrosis-associated factors (RUNX1 and TRAF2), TIMP-1, CCN1, integrin α11, an adhesion scaffold protein (TGFB1i1) and an enzyme mediating TGF-β1-induced fibrogenesis (ENPP1).

CONCLUSION

This study suggests that Cal administration may be a potential antifibrotic strategy via inhibiting TGF-β1-mediated PSC action during the development of ACP.

The research progress of anti-inflammatory and anti-fibrosis treatment of chronic pancreatitis

Chronic pancreatitis (CP) is a chronic progressive inflammatory disease of the pancreas, caused by multiple factors and accompanied by irreversible impairment of pancreatic internal and external secretory functions. Pathologically, atrophy of the pancreatic acini, tissue fibrosis or calcification, focal edema, inflammation, and necrosis are observed. Clinical manifestations include recurrent or persistent abdominal pain, diarrhea, emaciation, and diabetes. In addition, CP is prone to develop into pancreatic cancer(PC) due to persistent inflammation and fibrosis. The disease course is prolonged and the clinical prognosis is poor. Currently, clinical treatment of CP is still based on symptomatic treatment and there is a lack of effective etiological treatment. Encouragingly, experiments have shown that a variety of active substances have great potential in the etiological treatment of chronic pancreatitis. In this paper, we will review the pathogenesis of CP, as well as the research progress on anti-inflammatory and anti-fibrotic therapies, which will provide new ideas for the development of subsequent clinical studies and formulation of effective treatment programs, and help prevent CP from developing into pancreatic cancer and reduce the prevalence of PC as much as possible.

Vitamin D: A Potential Star for Treating Chronic Pancreatitis

Chronic pancreatitis (CP) is a chronic inflammatory and fibrotic disease of the pancreas. The incidence of CP is increasing worldwide but the effective therapies are lacking. Hence, it is necessary to identify economical and effective agents for the treatment of CP patients. Vitamin D (VD) and its analogues have been confirmed as pleiotropic regulators of cell proliferation, apoptosis, differentiation and autophagy. Clinical studies show that VD deficiency is prevalent in CP patients. However, the correlation between VD level and the risk of CP remains controversial. VD and its analogues have been demonstrated to inhibit pancreatic fibrosis by suppressing the activation of pancreatic stellate cells and the production of extracellular matrix. Limited clinical trials have shown that the supplement of VD can improve VD deficiency in patients with CP, suggesting a potential therapeutic value of VD in CP. However, the mechanisms by which VD and its analogues inhibit pancreatic fibrosis have not been fully elucidated. We are reviewing the current literature concerning the risk factors for developing CP, prevalence of VD deficiency in CP, mechanisms of VD action in PSC-mediated fibrogenesis during the development of CP and potential therapeutic applications of VD and its analogues in the treatment of CP.

Reversing insufficient photothermal therapy-induced tumor relapse and metastasis by regulating cancer-associated fibroblasts

Insufficient tumor accumulation and distribution of photosensitizers as well as low antitumor immunity severely restrict the therapeutic efficacy of photothermal therapy (PTT). Cancer-associated fibroblasts (CAFs) play a key role in tumor extracellular matrix (ECM) remodeling and immune evasion. Reshaping tumor microenvironment via CAF regulation might provide a potential approach for complete tumor elimination in combination with PTT. Here, tumor cell-derived microparticles co-delivering calcipotriol and Indocyanine green (Cal/ICG@MPs) are developed to modulate CAFs for improved PTT efficacy. Cal/ICG@MPs efficiently target tumor tissues and regulate CAFs to reduce tumor ECM, resulting in enhanced tumor accumulation and penetration of ICG to generate strong PTT efficacy and activate CD8⁺ T cell-mediated antitumor immunity. In addition, Cal/ICG@MPs-triggered CAF regulation enhances tumor infiltration of CD8⁺ T cells and ameliorates CAF-induced antigen-mediated activation-induced cell death of tumor-specific CD8⁺ T cells in response to PTT, eliciting long-term antitumor immune memory to inhibit tumor recurrence and metastasis. Our results support Cal/ICG@MPs as a promising drug to improve PTT efficacy in cancer treatment.

Photothermal therapy (PTT) has emerged as a promising approach for cancer treatment. Here, in preclinical cancer models, the authors show that PTT efficacy could be improved using tumor cell-derived microparticles that co-deliver the photosensitizer indocyanine green and a vitamin-D receptor ligand, calcipotriol, resulting in tumor extracellular matrix remodelling and ameliorated anti-tumor immune responses.

Vitamin D and Pancreatitis: A Narrative Review of Current Evidence

Emerging research indicates that vitamin D metabolic disorder plays a major role in both acute pancreatitis (AP) and chronic pancreatitis (CP). This has been demonstrated by studies showing that vitamin D deficiency is associated with pancreatitis and its anti-inflammatory and anti-fibrotic effects by binding with the vitamin D receptor (VDR). However, the role of vitamin D assessment and its management in pancreatitis remains poorly understood. In this narrative review, we discuss the recent advances in our understanding of the molecular mechanisms involved in vitamin D/VDR signaling in pancreatic cells; the evidence from observational studies and clinical trials that demonstrate the connection among vitamin D, pancreatitis and pancreatitis-related complications; and the route of administration of vitamin D supplementation in clinical practice. Although further research is still required to establish the protective role of vitamin D and its application in disease, evaluation of vitamin D levels and its supplementation should be important strategies for pancreatitis management according to currently available evidence.

The relationship between vitamin D receptor gene and TREM-1 gene polymorphisms and the susceptibility and prognosis of neonatal sepsis

Objective

The objective of this was to study the relationship between vitamin D receptor (VDR) and triggering receptor expressed on myeloid cells 1 (TREM‐1) gene single‐nucleotide polymorphisms (SNP) and neonatal sepsis susceptibility and prognosis.

Methods

The blood of 150 neonatal sepsis patients and 150 normal neonates was collected, and genomic DNA was extracted. Sanger sequencing was used to analyze the genotypes of VDR rs739837 and TREM‐1 rs2234246.

Results

Vitamin D receptor rs739837 locus GT, TT genotype, dominant model, and recessive model were all protective factors for sepsis (0 < OR < 1, p < 0.05). The risk of sepsis in carriers of the rs739837 G allele was 0.65 times that of the rs739837 T allele (95% CI: 0.50–0.83, p < 0.001), CT, TT, dominant model, and recessive model at rs2234246 were risk factors for sepsis (OR > 1, p < 0.05). The risk of sepsis in carriers of the rs739837 T allele was 1.38 times that of carriers of the C allele (95% CI: 1.16–1.61, p < 0.001). The polymorphisms of VDR gene rs739837 and TREM‐1 gene rs2234246 were not significantly correlated with the survival of patients with neonatal sepsis (p > 0.05).

Conclusion

Vitamin D receptor gene rs739837 locus G>T is associated with a reduction in the risk of neonatal sepsis, TREM‐1 rs2234246 C>T is associated with the increased risk of neonatal sepsis, but none of them was significantly associated with the prognosis of neonatal sepsis.

Pancreatic Stellate Cells: The Key Orchestrator of The Pancreatic Tumor Microenvironment

Pancreatic cancer is one of the most challenging adenocarcinomas due to its hostile molecular behavior and complex tumor microenvironment. It has been recently postulated that pancreatic stellate cells (PSCs), the resident lipid-storing cells of the pancreas, are important components of the tumor microenvironment as they can transdifferentiate into highly proliferative myofibroblasts in the context of tissue injury. Targeting tumor-stromal crosstalk in the tumor microenvironment has emerged as a promising therapeutic strategy against pancreatic cancer progression and metastasis. This chapter brings a broad view on the biological and pathological role of PSCs in the pancreas, activated stellate cells in the onset of tissue fibrosis, and tumor progression with particular emphasis on the bidirectional interactions between tumor cells and PSCs. Further, potential therapeutic regimens targeting activated PSCs in the pre-clinical and clinical trials are discussed.

Antifibrogenic effects of vitamin D derivatives on mouse pancreatic stellate cells

AIM

To study the molecular effects of three different D-vitamins, vitamin D2, vitamin D3 and calcipotriol, in pancreatic stellate cells (PSCs).

METHODS

Quiescent PSCs were isolated from mouse pancreas and activated in vitro by seeding on plastic surfaces. The cells were exposed to D-vitamins as primary cultures (early-activated PSCs) and upon re-culturing (fully-activated cells). Exhibition of vitamin A-containing lipid droplets was visualized by oil-red staining. Expression of α-smooth muscle actin (α-SMA), a marker of PSC activation, was monitored by immunofluorescence and immunoblot analysis. The rate of DNA synthesis was quantified by 5-bromo-2’-deoxyuridine (BrdU) incorporation assays. Real-time PCR was employed to monitor gene expression, and protein levels of interleukin-6 (IL-6) were measured by ELISA. Uptake of proline was determined using ¹⁸F-proline.

RESULTS

Sustained culture of originally quiescent PSCs induced cell proliferation, loss of lipid droplets and exhibition of stress fibers, indicating cell activation. When added to PSCs in primary culture, all three D-vitamins diminished expression of α-SMA (to 32%-39% of the level of control cells; P < 0.05) and increased the storage of lipids (scores from 1.97-2.15 on a scale from 0-3; controls: 1.49; P < 0.05). No such effects were observed when Dvitamins were added to fully-activated cells, while incorporation of BrdU remained unaffected under both experimental conditions. Treatment of re-cultured PSCs with Dvitamins was associated with lower expression of IL-6 (-42% to -49%; P < 0.05; also confirmed at the protein level) and increased expression of the vitamin D receptor gene (209%-321% vs controls; P < 0.05). There was no effect of Dvitamins on the expression of transforming growth factor-β1 and collagen type 1 (chain α1). The lowest uptake of proline, a main component of collagen, was observed in calcipotriol-treated PSCs.

CONCLUSION

The three D-vitamins inhibit, with similar efficiencies, activation of PSCs in vitro, but cannot reverse the phenotype once the cells are fully activated.

Pancreatic stellate cell: Pandora's box for pancreatic disease biology

Pancreatic stellate cells (PSCs) were identified in the early 1980s, but received much attention after 1998 when the methods to isolate and culture them from murine and human sources were developed. PSCs contribute to a small proportion of all pancreatic cells under physiological condition, but are essential for maintaining the normal pancreatic architecture. Quiescent PSCs are characterized by the presence of vitamin A laden lipid droplets. Upon PSC activation, these perinuclear lipid droplets disappear from the cytosol, attain a myofibroblast like phenotype and expresses the activation marker, alpha smooth muscle actin. PSCs maintain their activated phenotype via an autocrine loop involving different cytokines and contribute to progressive fibrosis in chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC). Several pathways (e.g., JAK-STAT, Smad, Wnt signaling, Hedgehog etc.), transcription factors and miRNAs have been implicated in the inflammatory and profibrogenic function of PSCs. The role of PSCs goes much beyond fibrosis/desmoplasia in PDAC. It is now shown that PSCs are involved in significant crosstalk between the pancreatic cancer cells and the cancer stroma. These interactions result in tumour progression, metastasis, tumour hypoxia, immune evasion and drug resistance. This is the rationale for therapeutic preclinical and clinical trials that have targeted PSCs and the cancer stroma.

Protective effects of vitamin D3 on fimbrial cells exposed to catalytic iron damage

Background

Recently, vitamin D₃ (1alpha, 25-dihydroxyvitamin D) has shown its capability to take part in many extraskeletal functions and its serum levels have been related to patient survival rate and malignancy of many types of neoplasms, including ovarian cancers. Catalytic iron is a free circulating form of iron that is able to generate reactive oxygen species and consequently to promote a number of cellular and tissutal dysfunctions including tumorigenesis. In fertile women an important source of catalytic iron is derived from retrograde menstruation. Epithelial secretory cells from fimbriae of fallopian tubes are greatly exposed to catalytic iron derived from menstrual reflux and so represent the site of origin for most serous ovarian cancers.

The aim of this study was to assess whether vitamin D₃ can play a role in counteracting catalytic iron-induced oxidative stress in cells from fimbriae of fallopian tubes.

Methods

The cells, isolated from women undergoing isteroannessiectomy, were treated with catalytic iron 50-75-100 mM and vitamin D₃ at a concentration ranging from 0.01 to 10 nM to study cell viability, radical oxygen species production, p53, pan-Ras, Ki67 and c-Myc protein expressions through Western Blot, and immunocytochemistry or immunofluorescence analysis.

Results

The pre-treatment with vitamin D₃ 1 nM showed its beneficial effects that consists in a significant decrease in ROS production. In addition a novel finding is represented by the demonstration that pre-treatment with vitamin D₃ is also able to significantly counteract tumoral biomarkers activation, such as p53, pan-Ras, Ki67 and c-Myc, and consequently the catalytic iron-induced cellular injury.

Conclusions

This study demonstrates for the first time that vitamin D₃ plays an important role in preventing catalytic iron-dependent oxidative stress in cultured fimbrial cells. These results support the hypothesis that vitamin D₃ could counteract carcinogenic changes induced by catalytic iron.

Reciprocal stimulation of pancreatic acinar and stellate cells in a novel long-term in vitro co-culture model

BACKGROUND/OBJECTIVES

Pancreatic stellate cells (PSCs) are the key fibrogenic cells in the pancreas. Acinar cell injury is known to trigger PSC activation. To facilitate the experimental analysis of the crosstalk between acinar cells and PSCs, an in vitro system for their long-term co-cultivation was developed.

MATERIALS AND METHODS

PSCs and acinar cells capable of retaining their secretory phenotype in long-term in vitro culture were obtained from mouse pancreata. A dual-chamber co-culture model was built in 24-well format with acinar cells seeded in the wells and PSCs in tissue culture inserts. Acinar cell-3T3 fibroblast co-cultures served as controls. After 4-day maintenance, the acinar compartment was analyzed for cell morphology, secretory capability, necrosis (HMGB1), apoptosis (TUNEL) and inflammation (NFκB). PSCs were analyzed for migratory activity and extracellular matrix (ECM) protein expression. The results were compared to parallel monocultures.

RESULTS

Acinar cells in monoculture and in co-culture with fibroblasts exhibited a healthy monolayer arrangement and an ability to respond to 0.1 nM caerulein stimulus by increased amylase release. Co-culture with PSCs caused marked changes in acinar cell morphology and rendered them insensitive to secretagogue stimulus. Activation of NFκB and necrotic changes, but not apoptosis, were identified in co-cultured acinar cells. Co-culture increased the migratory activity and ECM protein expression of PSCs.

CONCLUSIONS

Humoral interactions between acinar and PSCs in co-culture were shown to reciprocally affect their cellular functions. With its two separable cell compartments the co-culture system provides a versatile culture setting that allows independent manipulation and analysis of both cell types.

Targeting Transcriptional and Epigenetic Reprogramming in Stromal Cells in Fibrosis and Cancer

The basis of many human diseases arises from both genetic and epigenetic regulation. Recent advances in the understanding of the mechanisms underlying transcriptional and epigenetic regulation and their prevalence as contributors to a diverse range of human diseases have led us to focus on transcription and epigenetic changes in a variety of human disease conditions. Specifically, our recent studies in liver fibrosis and pancreatic cancer have demonstrated that the epigenetic regulation in hepatic stellate cells (HSCs) and pancreatic stellate cells (PSCs) significantly contributes to the progress in such diseases and presents great therapeutic potential. We show that the vitamin D receptor (VDR) acts as a master genomic suppressor in both HSC and PSC activation. The studies also have demonstrated that the VDR ligand reduces fibrosis and inflammation in a murine liver fibrosis and pancreatitis model. Although our current studies focus on characterizing the roles of VDR and regulatory regions within gene promoters and regulatory enhancers, we have expanded our effort to epigenetic mechanisms as major determinants of gene activation and repression in order to develop potential therapeutics to modulate stroma-associated pathologies including inflammation, fibrosis, and cancer.