Acinar Cells Research Articles

Increased expression of CXCL10 and CCL3 salivary gland chemokines in primary Sjögren's syndrome detected and systematically quantified using novel RNAscope® in situ hybridisation.

Primary Sjogren's syndrome is a chronic inflammatory disease characterised by the destruction of exocrine glands. We have previously shown significantly upregulated levels of CXCL10 and CCL3 chemokines in saliva from Sjogren's syndrome patients. In this study, we examined the expression pattern and localisation of these chemokines at the site of inflammation in patients' minor salivary glands using novel RNAscope® in situ hybridisation. Minor salivary glands from 33 primary Sjogren's syndrome patients and 22 non-Sjogren's syndrome sicca controls were included. The biopsies were formalin- fixed, paraffin-embedded and histopathologically evaluated. The CXCL10 and CCL3 mRNA expression in the glandular tissue was investigated using reverse transcription quantitative real-time polymerase chain reaction followed by RNAscope® in situ hybridisation. The mRNA expression of CXCL10 was higher than CCL3 in all patients. Significantly elevated expression of CXCL10 and CCL3 was detected in patients that also expressed autoantibody positivity and a positive biopsy for mononuclear cell infiltrates when compared to controls. CXCL10 was localised as clusters within focal infiltrates as well as adjacent to acinar and ductal epithelium, while CCL3 was expressed as scattered single mRNA molecules in focal infiltrates and in acinar cells. Our findings suggest CXCL10 as a possible disease biomarker in primary Sjogren's syndrome due to its upregulated expression in both saliva and minor salivary glands of patients and the localisation in the tissue. This should be re-assessed in a larger primary Sjogren's syndrome patient cohort, followed by additional functional studies to further validate its potential as a disease biomarker.

Inducible, but not constitutive, pancreatic REG/Reg isoforms are regulated by intestinal microbiota and pancreatic diseases.

The REG / Reg gene locus encodes for a conserved family of potent antimicrobial but also pancreatitis-associated proteins. Here we investigated whether REG/Reg family members differ in their baseline expression levels and abilities to be regulated in the pancreas and gut upon perturbations. We found, in human and mouse, pancreas and gut differed in REG / Reg isoform levels and preferences, with duodenum most resembling the pancreas. Pancreatic acinar cells and intestinal enterocytes were the dominant REG producers. Intestinal symbiotic microbes regulated the expression of the same, select Reg members in gut and pancreas. These Reg members had the most STAT3-binding sites close to the transcription start sites and were partially IL-22 dependent. We thus categorized them as "inducible" and others as "constitutive". Indeed, also in models of pancreatic-ductal adenocarcinoma and pancreatitis, only inducible Reg members were upregulated in pancreas. While intestinal Reg expression remained unchanged upon pancreatic perturbation, pancreatitis altered the microbial composition of the duodenum and feces shortly after disease onset. Our study reveals differential usage and regulation of REG / Reg isoforms as a mechanism for tissue-specific innate immunity, highlights the intimate connection of pancreas and duodenum, and implies a gut-to-pancreas communication axis resulting in a coordinated Reg response.

Examination of duodenal and colonic microbiome changes in mouse models of acute and chronic pancreatitis

The exocrine pancreas is the main source of digestive enzymes which are released from secretory vesicles of acinar cells into the small intestine. Enzymes, including amylases, proteases and lipases, degrade the ingested food and thus determine the nutritional substrate for the gut microbiota. Acute (AP) and chronic pancreatitis (CP) are associated with a transitional or progressive exocrine pancreatic dysfunction, we analysed in the present study how an experimental induction of pancreatitis in mouse models affects the colonic and duodenal microbiome composition. Evaluation by 16 S rRNA gene sequencing revealed specific microbiome changes in colonic as well as in duodenal samples in different models of AP and CP. Mild acute pancreatitis, which is associated with a transient impairment of pancreatic secretion showed only minor changes in microbial composition, comparable to the ones seen in progressive dysfunctional mouse models of CP. The strongest changes were observed in a mouse model of severe AP, which suggest a direct effect of the immune response on gut microbiome in addition to a pancreatic dysfunction. Our data indicate that highly dysbiotic microbiome changes during pancreatitis are more associated with the inflammatory reaction than with a disturbed pancreatic secretion.

Fecal glycoprotein 2 is a marker of gut microbiota dysbiosis and systemic inflammation

BackgroundAntimicrobial autoantigenic glycoprotein 2 (GP2) is an important component of the innate immune system which originates from the exocrine pancreas as well as from the small intestines. The relationship of GP2 with the intestinal microbiome as well as the systemic implications of increased fecal GP2 levels are, however, still unclear. Therefore, fecal samples from 2,812 individuals of the Study of Health in Pomerania (SHIP) were collected to determine GP2 levels (enzyme-linked immunosorbent assay) and gut microbiota profiles (16 S rRNA gene sequencing). These data were correlated and associated with highly standardised and comprehensive phenotypic data of the study participants.ResultsFecal GP2 levels were increased in individuals with higher body mass index and smokers, whereas lower levels were found in case of preserved exocrine pancreatic function, female sex or a healthier diet. Moreover, higher GP2 levels were associated with increased serum levels of high-sensitivity C-reactive protein, loss of gut microbial diversity and an increase of potentially detrimental bacteria (Streptococcus, Haemophilus, Clostridium XIVa, or Collinsella). At the same time, predicted microbial pathways for the biosynthesis of beneficial short-chain fatty acids or lactic acid were depleted in individuals with high fecal GP2. Of note, GP2 exhibited a stronger association to overall microbiome variation than calprotectin.ConclusionFecal GP2 is a biomarker of gut microbiota dysbiosis and associated with increased systemic inflammation. The intestines may be more important as origin for GP2 than pancreatic acinar cells. Future studies need to investigate the potential clinical value in disease specific patient cohorts.

Application of LEF-1 immunohistochemical staining in the diagnosis of solid pseudopapillary neoplasm of the pancreas

IntroductionSolid pseudopapillary neoplasm (SPN) is a tumor of young females with gain-of-function mutation in catenin beta 1 gene involved in Wnt signal transduction pathway. Beta-catenin immunohistochemistry (IHC) is used to diagnose SPN. Lymphoid enhancer-binding factor 1 (LEF-1) has been recognized in the transactivation of Wnt pathway. We aim to study LEF-1 IHC in SPN and other pancreatic tumors and compare it with beta-catenin IHC. MethodsWe retrieved cases of SPN, pancreatic neuroendocrine tumor (PanNET), serous cystadenoma (SCA), ductal adenocarcinoma (PDAC) and acinar cell carcinoma (ACC) from 2011 to 2023. Formalin-fixed, paraffin-embedded blocks with adequate tumor were cut and stained with beta-catenin (B-Catenin-1 clone) and LEF-1 (EP310 clone) IHC. Cases were reviewed by two pathologists independently. Nuclear staining with LEF-1 and beta-catenin was considered as positive. ResultsOur cohort consisted of 111 cases [SPN = 59 (42 resections, 11 FNA, 6 biopsies), PDAC = 24, PanNET = 22, SCA = 5, ACC = 1]. For SPN cases male to female ratio was1:8. Age ranged from 9 to 81 years (average: 32 years). Pancreatic tail was the most common location (47 %) followed by head (28 %), body (19 %) and neck (6 %). Tumor size ranged from 1.0 to 12.2 cm (average: 5 cm). Among the SPN cases 57/59 demonstrated strong nuclear LEF-1 staining. 2/49 cases were negative for LEF-1 (both pathologist in agreement). All SPN tumors demonstrated nuclear staining with beta-catenin. Among the non-SPN tumors, beta-catenin showed nuclear staining in 2/52 cases (2 PDAC). The remaining 50 cases were negative for nuclear beta-catenin and demonstrated variable staining pattern with interpretation variability between the two pathologists. The sensitivity and specificity for LEF-1 were 97 % and 100 %, respectively, while for beta-catenin, they were 100 % and 96 % respectively. ConclusionCrisp nuclear staining of LEF-1 without background staining makes diagnostic interpretation relatively easy and accurate compared to beta-catenin IHC. This is further helpful for small biopsy samples to help differentiate SPN from mimickers such as PanNET. None of the non-SPN cases displayed nuclear LEF-1 rendering it a valuable adjunct to beta-catenin in the diagnostic evaluation of SPN.

Vitamin B12 protects necrosis of acinar cells in pancreatic tissues with acute pancreatitis.

Pharmacological agents regarding the most optimal treatments of acute pancreatitis remain. One-carbon metabolism nutrients as therapeutic agents in many diseases might be involved in acute pancreatitis. The roles are acquired exploration in acute pancreatitis. We utilized Mendelian randomization to assess the causal impact of folate, homocysteine, and vitamin B12 (VB12) on acute pancreatitis. Wild-type and corresponding genetically modified mouse models were used to verify the genetic correlating findings. A negative association between genetically predicted serum VB12 levels and risks of acute pancreatitis was identified in human population. The transcobalamin receptor (TCblR)/CD320 gene ablation that decreased cellular VB12 uptake and ATP production in pancreatic tissues promoted necrosis, resulting in much severe pathological changes of induced acute pancreatitis in mice. VB12 pretreatment and posttreatment dramatically increased ATP levels in pancreatic tissues and reduced the necrosis, then the elevated levels of amylase in serum, the levels of CK-19, the activity of trypsin, and T lymphocyte infiltration in pancreatic tissues, prevented the pancreatic gross loss and ameliorated histopathological changes of mouse pancreases with induced acute pancreatitis. The results reveal that VB12 is potential as a therapeutic agent to inhibit tissue injuries and adaptive inflammatory responses in the pancreas in patients with acute pancreatitis.

A Curious Case of Pancreatoblastoma in an Older Age Woman

Abstract Introduction/Objective Pancreatoblastoma is a malignant epithelial neoplasm of the pancreas and displays multiple lines of differentiation with acinar differentiation as the predominant pattern. The squamoid nests are considered a defining component of pancreatoblastoma. Pancreatoblastoma is seen most often in children, however, rare cases in adults have been described in the literature. In children, most pancreatoblastomas are indolent and curable, however, the prognosis is worse in adults due to the presence of frequent metastasis. Methods/Case Report We report an interesting case of pancreatoblastoma in a 65-year-old woman with no pertinent medical history who presented with abdominal discomfort. MRI abdomen showed an 11.3 cm mass with central necrosis within the head of the pancreas. Fine-needle aspiration (FNA) of the mass showed monotonous cells with neuroendocrine differentiation and FNA was signed out as a low-grade neuroendocrine tumor (NET). The patient underwent a Whipple resection for a presumed NET. On gross examination, a 14 cm large solid, fleshy, lobulated, partially encapsulated mass was noted in the head of the pancreas. H&E slides on low power showed the tumor composed of highly cellular lobules separated by fibrous bands. Within the lobules, the neoplastic cells predominantly had an acinar differentiation with focal trabecular or solid areas. Dispersed within the tumor were squamoid nests composed of plump to spindle-shaped cells with abundant eosinophilic cytoplasm arranged in whorls. Immunohistochemical stains demonstrated squamoid nests being positive for CK5/6 and had a nuclear-staining pattern with beta-catenin. The remaining tumor was positive for trypsin, chymotrypsin, BCL-10, synaptophysin (focal), chromogranin (focal), and INSM-1 (patchy). On MSK-Impact (next- generation sequencing), a mutation in CTNNB1 was detected. Results (if a Case Study enter NA) NA Conclusion In adults, it is important to consider pancreatoblastoma in the differential diagnoses of solid pancreatic tumors while being cautious not to confuse it with neuroendocrine tumor or acinar cell carcinoma. The presence of squamoid nests is critical for its diagnosis. Making a diagnosis of pancreatoblastoma through FNA or pancreatic biopsy can be exceptionally challenging in cases lacking squamoid nests.

Crashing into Discovery: Nesidioblastosis in Adult, Unmasked post-Motor Vehicle Accident - A Case Study and Literature Review

Abstract Introduction/Objective Nesidioblastosis, characterized by pancreatic duct-derived B-islet cell proliferation, typically manifests with hypoglycemic symptoms. While more common in newborns, it can rarely affect adults. Here, we report an incidental finding of nesidioblastosis in a 37-year-old female following abdominal trauma due to a motor vehicle crash (MVC). Methods/Case Report A 37-year-old female with no notable medical history presented with blunt abdominal trauma following an MVC. The emergency evaluation revealed a grade 4 traumatic splenic laceration and severe hemoperitoneum. Preoperative lab results showed decreased hemoglobin, elevated white cell count, prolonged prothrombin time, and reduced calcium and magnesium levels. The patient underwent a splenectomy along with a distal pancreatectomy. While grossly unremarkable, microscopic examination revealed maintained acinar architecture with focal hyperplasia around pancreatic ducts. Enlarged acinar cells with pleomorphic nuclei and prominent nucleoli were consistent with focal nesidioblastosis. Results (if a Case Study enter NA) NA Conclusion Multiple studies have documented the first reported case of nesidioblastosis in adults was in 1975. While its exact incidence is uncertain, most sources suggest a relative frequency of 0.5 – 7% of persistent hyperinsulinemic hypoglycemia, with estimated overall an annual rate of around 9 per 100,000, with a higher occurrence among females. This unusual incidental discovery of nesidioblastosis in an asymptomatic patient undergoing pancreatic resection for unrelated reasons highlights the likelihood of underestimating the actual prevalence of this disease.

Embryonic macrophages support endocrine commitment during human pancreatic differentiation

Organogenesis is a complex process that relies on a dynamic interplay between extrinsic factors originating from the microenvironment and tissue-specific intrinsic factors. For pancreatic endocrine cells, the local niche consists of acinar and ductal cells as well as neuronal, immune, endothelial, and stromal cells. Hematopoietic cells have been detected in human pancreas as early as 6 post-conception weeks, but whether they play a role during human endocrinogenesis remains unknown. To investigate this, we performed single-nucleus RNA sequencing (snRNA-seq) of the second-trimester human pancreas and identified a wide range of hematopoietic cells, including two distinct subsets of tissue-resident macrophages. Leveraging this discovery, we developed a co-culture system of human embryonic stem cell-derived endocrine-macrophage organoids to model their interaction invitro. Here, we show that macrophages support the differentiation and viability of endocrine cells invitro and enhance tissue engraftment, highlighting their potential role in tissue engineering strategies for diabetes.

Regulatory network analysis of Dclk1 gene expression reveals a tuft cell-ILC2 axis that inhibits pancreatic tumor progression.

Dclk1 expression defines a rare population of cells in the normal pancreas whose frequency is increased at early stages of pancreatic tumorigenesis. The identity and the precise roles of Dclk1 expressing cells in pancreas have been matter of debate, although evidence suggests their involvement in a number of key functions, including regeneration and neoplasia. We employed a recently developed Dclk1 reporter mouse model and single cell RNAseq analysis to define Dclk1 expressing cells in normal pancreas and pancreatic neoplasia. In normal pancreas, Dclk1 epithelial expression identifies subsets of ductal, islet and acinar cells. In pancreatic neoplasia, Dclk1 expression identifies five epithelial cell populations, among which acinar-to-ductal metaplasia (ADM)-like cells and tuft-like cells are predominant. These two cell populations play opposing roles in pancreatic neoplasia, with Dclk1+ ADM-like cells sustaining tumor growth while Dclk1+ tuft-like cells restraining tumor progression. The differentiation of Kras mutant acinar cells into Dclk1+ tuft-like cells requires the activation of the transcription factor SPIB and is further supported by a cellular paracrine loop involving cancer group 2 innate lymphoid cells (ILC2) and cancer activated fibroblasts (CAFs) that provide IL13 and IL33, respectively. In turn, Dclk1+ tuft-like cells release angiotensinogen that plays protective roles against pancreatic neoplasia. Overall, our study provides novel insights on the biology of Dclk1+ cells in normal pancreas and unveils a protective axis against pancreatic neoplasia, involving CAFs, ILC2 and Dclk1+ tuft-like cells, which ultimately results in angiotensinogen release.

Glucotoxicity suppresses function of pancreatic beta and duct cells via miR-335-targeted Runx2 and insulin-mediated mechanism.

Pancreatic cell dynamics have important contributions to the development of type 2 diabetes and related diseases such as nonalcoholic fatty pancreas disease. The aim of this study was to investigate the effects of prolonged excessive glucose exposure on the functions of pancreatic beta cells and duct cells in single and co-culture conditions. In this study, we focused on the effects of glucotoxicity on insulin secretion which is the main function of beta cells and on progenitor functions of duct cells. Rat primary INS1 beta cells and ARIP duct cells were exposed to glucose (25mM) for 72h under single or indirect co-culture conditions. Glucotoxicity stimuli increased insulin secretion and decreased insulin expression in single beta cells while stimulating beta-cell differentiation and adipogenesis in single duct cells. On the other hand, glucotoxicity caused functional loss and increased proliferation and apoptosis in beta cells while increasing proliferation but suppressed beta-cell differentiation and adipogenesis in duct cells under co-culture conditions. The expression level of miR-335, a microRNA known to be upregulated by leptin and target Runx2, was measured. As a result, unlike single-cell culture, glucotoxicity upregulated miR-335, downregulated Runx2, and decreased insulin signaling in beta cells while downregulating miR-335 and upregulating Runx2, and decreased insulin signaling in duct cells under co-culture conditions. When the results of single and co-culture experiments are compared, insulin and miR-335 may be seen as important mediators for setting up the relation between beta and duct cells. Our findings are important for preventing the development of type 2 diabetes and nonalcoholic fatty pancreas disease, even developing new diagnosis and treatment strategies.

Spatial Transcriptomics Unravel the Tissue Complexity of Oral Pathogenesis.

Spatial transcriptomics (ST) is a cutting-edge methodology that enables the simultaneous profiling of global gene expression and spatial information within histological tissue sections. Traditional transcriptomic methods lack the spatial resolution required to sufficiently examine the complex interrelationships between cellular regions in diseased and healthy tissue states. We review the general workflows for ST, from specimen processing to ST data analysis and interpretations of the ST dataset using visualizations and cell deconvolution approaches. We show how recent studies used ST to explore the development or pathogenesis of specific craniofacial regions, including the cranium, palate, salivary glands, tongue, floor of mouth, oropharynx, and periodontium. Analyses of cranial suture patency and palatal fusion during development using ST identified spatial patterns of bone morphogenetic protein in sutures and osteogenic differentiation pathways in the palate, in addition to the discovery of several genes expressed at critical locations during craniofacial development. ST of salivary glands from patients with Sjögren's disease revealed co-localization of autoimmune antigens with ductal cells and a subpopulation of acinar cells that was specifically depleted by the dysregulated autoimmune response. ST of head and neck lesions, such as premalignant leukoplakia progressing to established oral squamous cell carcinomas, oral cancers with perineural invasions, and oropharyngeal lesions associated with HPV infection spatially profiled the complex tumor microenvironment, showing functionally important gene signatures of tumor cell differentiation, invasion, and nontumor cell dysregulation within patient biopsies. ST also enabled the localization of periodontal disease-associated gene expression signatures within gingival tissues, including genes involved in inflammation, and the discovery of a fibroblast subtype mediating the transition between innate and adaptive immune responses in periodontitis. The increased use of ST, especially in conjunction with single-cell analyses, promises to improve our understandings of craniofacial development and pathogenesis at unprecedented tissue-level resolution in both space and time.

Molecular and Clinical Features of Pancreatic Acinar Cell Carcinoma: A Single-Institution Case Series

Objectives: Acinar cell carcinoma (ACC) accounts for about 1% of pancreatic cancers. The molecular and clinical features of ACC are less characterized than those of pancreatic ductal adenocarcinoma. Methods: We retrospectively evaluated the clinical and molecular features of ACC patients who underwent germline and/or somatic molecular testing at The University of Texas MD Anderson Cancer Center from 2008 to 2022 and two cases from 2023–2024 who underwent RNA and TME analysis by Boston Gene. Patient information was extracted from our institutional database with the approval of the Institutional Review Board. Results: We identified 16 patients with available molecular testing results. Fourteen patients had metastatic disease, one had borderline resectable disease, and one had localized resectable disease at diagnosis. Fifteen patients were wild type for KRAS (one patient had unknown KRAS status). Somatic/germline mutations of DNA damage repair genes (BRCA1/2, PALB2, and ATM) were present in 5 of 12 patients tested for these genes. One patient was found to have RET fusion and responded favorably to selpercatinib for over 42 months. The median overall survival (OS) was 24 months for patients with metastatic disease. One of the additional two cases who underwent BostonGene testing was found to have NTRK1 fusion. RNA and TME analysis by Boston Gene of the two cases reported immune desert features and relatively lower RNA levels of CEACAM5, CD47, CD74, and MMP1 and higher RNA levels of CDH6 compared with PDAC.

Cultures derived from pancreatic cancer xenografts with long-term gemcitabine treatment produce chemoresistant secondary xenografts: Establishment of isogenic gemcitabine-sensitive and -resistant models

In attempts to establish sophisticated models to reproduce the process of acquired drug resistance, we transformed normal human pancreatic ductal epithelial cells by introducing genes for multiple cellular factors. We also created isogenic gemcitabine-sensitive and -resistant models by short- and long-term gemcitabine treatment, respectively. These models demonstrated differences in drug resistance in vivo, but not in vitro. Gemcitabine treatment also induced squamous transdifferentiation in xenografts in mice. The transcription factor p63 was identified as a possible resistance-determining factor but was unlikely to be solely responsible for the resistance to gemcitabine. This system would prove useful to discover novel molecular targets to overcome chemotherapy resistance, by allowing the evaluation of molecules of interest in xenograft models after in vitro genetic ablation.

8182 New Mouse Model Mirrors Human MODY8: Opening Doors to Understanding Exocrine-Endocrine Crosstalk in the Diabetic Pancreas

Abstract Disclosure: K. El Jellas: None. V. Salerno: None. L.S. Katz: None. J. Hu: None. G. Fogarty: None. A. Mandal: None. A. DiStefano-Forti: None. D. Scott: None. M. Lowe: None. A. Molven: None. R.N. Kulkarni: None. Maturity-onset diabetes of the young, type 8 (MODY8) is a dominantly inherited form of monogenic diabetes, caused by heterozygous mutations in the carboxyl ester lipase (CEL) gene expressed in pancreatic acinar cells. MODY8 is characterized by chronic pancreatitis and exocrine dysfunction. Despite the intimate anatomical relationship between the endocrine and exocrine pancreas, little is known about the biological components mediating exocrine-endocrine communication in regulating glucose homeostasis. Here, we report a refined mouse model that bears the mutation present in MODY8 patients on one allele, and the humanized normal variable number of tandem repeat (VNTR) of CEL with 16 repeats (16R) on the other, mimicking the genetic make-up seen in MODY8 patients. Examination of glucose homeostasis revealed that inducing stress (e.g. by high-fat diet) leads to glucose intolerance in MODY8/16R mice and a blunted glucose-stimulated insulin-secretion compared to their control littermates. Histopathological analyses demonstrated features of chronic pancreatitis in some pancreatic lobes, including inflammation, acinar atrophy, acinar-to-ductal metaplasia, fibrosis and fat infiltration, mirroring the morphology of the human disease. Moreover, we applied immunolabeling-enabled three-dimensional imaging of solvent-cleared organs (iDISCO) to intact pancreata and found that beta-cell mass was significantly decreased in the MODY8/16R mice, with a large number of islets located within fatty lobes. These results are coupled with comparative proteomics and lipidomic profiling with the aim of understanding the molecular signatures of exocrine and endocrine cells during pathogenesis. In conclusion, we have generated a mouse that recapitulates several features of the exocrine and endocrine phenotype characteristic of human MODY8. This novel model provides a unique opportunity, not possible in humans, to characterize pancreatic endocrine-exocrine communication in a longitudinal manner as a response to diverse environmental stressors. Presentation: 6/2/2024

Proteomic basis for pancreatic acinar cell carcinoma and pancreatoblastoma as similar yet distinct entities

Acinar cell carcinoma (ACC) and pancreatoblastoma (PBL) are rare pancreatic malignancies with acinar differentiation. Proteogenomic profiling of ACC and PBL revealed distinct protein expression patterns compared to pancreatic ductal adenocarcinoma (PDAC) and benign pancreas. ACC and PBL exhibited similarities, with enrichment in proteins related to RNA processing, chromosome organization, and the mitoribosome, while PDACs overexpressed proteins associated with actin-based processes, extracellular matrix, and immune-active stroma. Pathway activity differences in metabolic adaptation, epithelial-to-mesenchymal transition, and DNA repair were characterized between these diseases. PBL showed upregulation of Wnt-CTNNB1 and IGF2 pathways. Seventeen ACC-specific proteins suggested connections to metabolic diseases with mitochondrial dysfunction, while 34 PBL-specific proteins marked this pediatric cancer with an embryonic stem cell phenotype and alterations in chromosomal proteins and the cell cycle. This study provides novel insights into the proteomic landscapes of ACC and PBL, offering potential targets for diagnostic and therapeutic development.

Immortalized mesenchymal stromal cells overexpressing alpha-1 antitrypsin protect acinar cells from apoptotic and ferroptotic cell death.

Chronic pancreatitis (CP) is a progressive inflammatory disorder that impairs endocrine and exocrine function. Our previous work showed that mesenchymal stem/stromal cells (MSCs) and MSCs overexpressing alpha-1 antitrypsin (AAT-MSCs) could be therapeutic tools for CP. However, primary MSCs are predisposed to undergo senescence during culture expansion, which limits their therapeutic applications. We generated and characterized immortalized human MSCs (iMSCs) and AAT-MSCs (iAAT-MSCs) and tested their protective effect on 2,4,6-Trinitrobenzenesulfonic acid (TNBS)-induced acinar cell death in an invitro cell culture system. Primary MSCs were immortalized by transduction with simian virus 40 large T antigen (SV40LT), and the resulting iMSC and iAAT-MSC lines were analysed for proliferation, senescence, phenotype and multi-differentiation potential. Subsequently, apoptosis and ferroptosis pathways were investigated by assessing changes before and after TNBS treatment. Coculture of iMSCs and iAAT-MSCs with acinar cell lines inhibited early cell death induced by TNBS, reduced ER stress and reversed TNBS-induced protein reduction at tight junctions. Additionally, iMSCs and iAAT-MSCs exerted such protection by regulating mitochondrial respiration, ATP content and ROS production in TNBS-induced acinar cells. Furthermore, iMSCs and iAAT-MSCs ameliorated TNBS-induced ferroptosis by modulating iron generation and ROS production and regulating the ferritin heavy chain 1 (FTH1)/protein disulfide isomerase (PDI)/glutathione peroxide 4 (GPX4) signalling pathways in acinar cells. These findings identify ferroptosis as an unrecognized mechanism that leads to TNBS-induced cell death and offer mechanistic insights relevant to using stem cell therapy to treat acinar cell death associated with CP.

BMAL1 Deficiency Provokes Dry Mouth and Eyes by Down-regulating ITPR2/3

Secretory glands, responsible for tears and saliva production, play essential roles in maintaining ocular and oral well-being. Disruptions in gland secretion can arise from various factors, including rhythm disturbances associated with sleep disorders. However, the underlying mechanisms governing these disruptions remain largely unexplored. We demonstrate that BMAL1, a core component of the circadian system, plays a critical role in regulating secretory gland secretion. Loss of BMAL1 induces vacuolation and atrophy phenotypes in acinar cells, subsequently leading to cell apoptosis and gland hypofunction, but does not cause Sjogren's syndrome, which is characterized by localized inflammatory cell infiltration. Mechanically, BMAL1 directly modulates the transcription of ITPR2 and ITPR3, thereby altering the secretion of Lactoferrin and Lysozyme. Restoration of ITPR2 and ITPR3 expression in Bmal1-deficient rats effectively alleviated the symptoms of lacrimal and parotid glands secretory dysfunction and significantly reduced dry mouth and dry eye conditions in rhythm-disordered rats. These findings highlight the essential role of BMAL1 in regulating salivary and lacrimal gland secretion and suggest a novel therapeutic approach for treating dry mouth and dry eyes associated with rhythm disorders.

Cholic acid activation of GPBAR1 does not induce or exacerbate acute pancreatitis but promotes exocrine pancreatic secretion

Obstruction of bile ducts due to gallstones can lead to biliary acute pancreatitis (BAP). According to Perides et al., G protein-coupled bile acid receptor-1 (GPBAR1) mediates BAP. However, Zi’s findings suggest that GPR39, rather than GPBAR1, mediates TLCAS-induced increases in cytosolic calcium and acinar cell necrosis, casting doubt on the role of GPBAR1 in BAP. Numerous G protein-coupled receptors on pancreatic acinar cells utilize Ca2+ and cyclic adenosine monophosphate (cAMP) as second messengers to manage pancreatic exocrine secretion, with significant cross-talk between these signals. The primary bile acid cholic acid (CA) and its conjugated forms are predominant in the human gallbladder. This study aimed to clarify the role and physiological significance of GPBAR1 by investigating the physiological and pathological effects of CA activation on GPBAR1 in pancreatic acinar cells. Isolated rat pancreatic acinar cells were treated with CA and CCK in vitro to observe the effect of CA-induced cAMP signaling on CCK-induced physiological and pathological calcium signaling. In vivo evaluations involved reverse biliopancreatic duct injections of 5% sodium taurocholate (STC) or 5% CA in rats. CA induced intracellular cAMP signaling in a concentration-dependent manner without increasing the intracellular Ca2+ concentration. CA did not independently cause calcium overload or enzyme activation, nor did it exacerbate calcium overload or enzyme activation from high-dose CCK. Reverse biliopancreatic duct injections of 5% CA did not cause acute pancreatitis in the rats. Transcriptomic analysis revealed that 50 μM CA induced changes in gene expression related to protein synthesis in the endoplasmic reticulum and ribosomes. Furthermore, 50 μM CA accelerated the calcium waves and increased the enzyme secretion induced by CCK. GPBAR1 was found on the basolateral membrane in rat pancreatic tissue rather than near the apical region of acinar cells.GPBAR1 activation is not crucial for BAP activity but may play a role in bile acid regulation of pancreatic exocrine secretion, suggesting that GPBAR1 is a potential therapeutic target for pancreatic exocrine insufficiency.

Pancreatic Differentiation of Oral Minor Salivary Gland Stem Cells.

Stem cells from various sources including major salivary glands have been used to establish pancreatic differentiation in an attempt to provide new treatment options for patients with diabetes mellitus. In contrast, the potential of using the more easily accessible intraoral minor salivary glands has not been evaluated so far. Salivary stem cells were isolated from normal labial minor salivary glands that were removed during the excision of a mucocele and were attempted to differentiate into pancreatic cell lines using a culture medium enriched with activin A, retinoic acid and GLP-1.Real time RT-PCR was used to evaluate the expression of the genes of pancreatic transcription factors MafA, Ptf1a, Hb9 and Arx. Complementary, 22 labial minor salivary gland paraffin-embedded specimens were examined using immunohistochemistry for the presence of the relevant gene products of the pancreatic transcription factors Arx, MafA, Ptf1a and Pdx1. The differentiated salivary stem cells(cells of passage 3) expressed the genes of the pancreatic transcription factors MafA, Ptf1a, Hb9 and Arx even on the first day of the experiment while immunohistochemistry also confirmed the presence of the protein products of Arx, MafA, Ptf1a as well as Pdx1[> 50% of the specimens for Arx(5/8) and MafA(7/8), < 50% for Ptf1a(5/11) and Pdx1(5/11)] in ducts, mesenchymal connective tissue and acinar cells. Labial minor salivary glands may share gene and protein characteristics with pancreas suggesting a possible usefulness for pancreatic regeneration or substitution in cases of deficiency.