Proliferation Of Duct Epithelial Cells Research Articles

Acute pancreatitis in intraductal papillary mucinous neoplasm: a single-center retrospective cohort study with systematic review and meta-analysis

BackgroundIntraductal papillary mucinous neoplasm (IPMN) is a cystic tumor of the pancreas arising from abnormal papillary proliferation of ductal epithelial cells, and is a precancerous lesion of pancreatic malignancy. This study aimed to evaluate associations between acute pancreatitis (AP) and histologic subtypes of IPMN.MethodsIn the clinical study, patients with IPMN confirmed by surgical resection specimens at our institute between 2009 and 2021 were eligible for inclusion. Associations and predictive accuracy of AP on the presence of HGD were determined by logistic regressions. In addition, a systematic review and meta-analysis was conducted through literatures upon search in PubMed, Embase, CENTRAL, China National Knowledge Infrastructure (CKNI), and Wanfang database, up to June, 2023. Pooled effects of the associations between AP and HGD and intestinal epithelial subtype subtype, shown as odds ratios (ORs) with 95% confidence intervals (CIs), were calculated using random effects model.ResultsThe retrospective cohort study included 47 patients (32 males, 15 females) diagnosed with IPMN at our center between 2009 and 2021, including 11 cases with AP (median 62 years) and 36 cases (median 64.5 years) without. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of AP in predicting HGD were 78.7%, 57.1%, 82.5%, 36.4%, and 91.7%, respectively. Univariate logistic regression analysis showed that AP group had greater odds of presence of HGD (OR: 6.29,95% CI: 1.14–34.57) than non-AP group. Meta-analysis of five case-control studies in the literature included 930 patients and showed that AP-IPMN patients had higher odds for HGD (OR: 2.13, 95% CI 1.38–3.29) and intestinal epithelial subtype (OR: 5.38, 95% CI: 3.50–8.27) compared to non-AP IPMN.ConclusionsAP is predictive of malignancy in patients with IPMN.

Korelacija između broja ćelija duktusa dojke koje eksprimiraju androgenske, estrogenske i progesteronske receptore i veličine promene kod obolelih od ginekomastije

Introduction: Gynecomastia is an abnormal growth of the male breast due to excessive proliferation of ductal epithelial cells. It usually occurs during puberty, so the influence of hormones on the stimulation of ductal cells is indicative. Androgen, estrogen and progesterone are steroid hormones that exert their influence by binding to intracellular receptors and thus activating transcriptional mechanisms, i.e. act as trophic factors. Material and methods: A retrospective study for the period 01.01.2021-31.12.2021 was performed and 6 patients were found, of which in two cases left and right breast gynecomastia surgeries were performed. Hematoxylin-eosin (HE) stained slides and corresponding paraffin blocks were taken from the archive, and a tissue microarray was constructed, with 4 tissue cylinders for each tissue sample. Immunohistochemical staining was performed for androgen, estrogen, and progesterone receptors. The obtained slides were scanned on a Leica Biosystems Aperio AT2 slide scanner, and image analysis was performed in the Aperio Image Scope program. Statistical analysis of the data was performed by the EZR R Commander program. Results: Of the 8 samples, none showed significant androgen receptor expression. Statistical analysis of the number of cells expressing estrogen receptors (p s = 0.03676; rho = 0.7619048) progesterone (p s = 0.002439; rho = 0.8982197) and the volume of tissue removed showed a statistically significant positive correlation. Conclusion: The obtained results confirm the hypothesis that the volume of removed breast tissue in patients with gynecomastia correlates with the expression of estrogen and progesterone receptors, but further research on a larger sample is necessary for more reliable conclusions.

Parasympathetic-macrophages-ductal epithelial cells axis promotes female rat submandibular gland regeneration after excretory duct ligation/deligation

ObjectiveSubmandibular gland (SMG) regeneration depends on parasympathetic signals that modulate this process primarily by promoting ductal epithelial cell proliferation. The purpose of this study was to elucidate the mechanism underlying of parasympathetic regulation on salivary gland regeneration. Materials and methodsWe performed duct ligation/deligation with or without chorda lingual innervation in female Sprague-Dawley rats. Clodronate liposomes were administered retroductally and intravenously into the SMG to deplete macrophages. The proliferative ability and cell cycle-related genes of SMG were assessed using western blotting, quantitative real-time PCR, and immunohistochemical staining. ResultsParasympathetic stimulation boosted Interleukin-6 (IL-6) release by macrophage via muscarinic signalling. This process was suppressed by denervation, muscarinic blockade, or SMG macrophage depletion. SMG IL-6 release led to signal transducer and activator of transcription 3 (STAT3) phosphorylation in ductal epithelial cells to promote proliferation and regeneration by upregulating the expression of cell cycle-related genes. SMG parasympathetic denervation and macrophage depletion suppressed cell cycle-related genes upregulation and ductal cells proliferation. ConclusionsThese data indicated that the parasympathetic-macrophage-ductal epithelial cells axis promote SMG regeneration after duct ligation and deligation.

Co-exposure to BPA and DEHP enhances susceptibility of mammary tumors via up-regulating Esr1/HDAC6 pathway in female rats

Breast cancer (BrCa) as one of the major malignancies threatening women's health worldwide occurs due to the genetic and environmental interactions. Epidemiological studies have suggested that exposure to endocrine disrupting chemicals (EDCs) can elevate the risk of breast cancer. Di-(2-ethylhexyl)-phthalate (DEHP) and bisphenol A (BPA) are known as two typical EDCs. Although several studies have implied that there appear to have adverse effects of exposure to BPA or DEHP alone on breast development, no study to date has demonstrated the exact toxic effect of combined exposure to DEHP and BPA on breast tumorigenesis. In the present study, we performed an in vivo experiment including 160 female Sprague-Dawley (SD) rats, in which 80 rats were randomly allocated to 4 groups including control group given to normal diet, DEHP (150 mg/kg body weight/day), BPA (20 mg/kg body weight/day), and DEHP (150 mg/kg body weight/day) combined with BPA (20 mg/kg body weight/day) by gavage for 30 weeks. Additionally, a DEN/MNU/DHPN (DMD)-induced carcinogenesis animal model was also established to assess their effect on tumor promotion. Namely, the other 80 SD rats were separated into another 4 groups: in addition to DMD initiation each group treated with vehicle, DEHP, BPA and the combination of BPA and DEHP respectively. Our data demonstrated that BPA alone or in combination with DEHP may induce hyperplasia of mammary glands, including the proliferation of ductal epithelial cells and an increase in the number of lobules and acinus after a 30-week exposure. Notably, co-exposure to DEHP and BPA increased the incidence and reduced the latency of mammary tumor, which seemed to enhance the susceptibility of carcinogens-induced tumor. Mechanistically, our results supported the hypothesis that exposure to BPA and DEHP might promote breast cancer dependent on Esr1 and HDAC6 as pivotal factors, and further lead to the activation of oncogene c-Myc. Our study suggested that BPA combined with DEHP facilitate the occurrence of mammary tumors, which contributed to advance our understanding in the complex effects of compound exposure to endocrine disrupting chemicals.

Genome-wide DNA methylome and whole-transcriptome landscapes of spontaneous intraductal papilloma in tree shrews.

BackgroundBreast intraductal papilloma (IP) is mainly caused by the abnormal proliferation of ductal epithelial cells. Tree shrews have potential as an animal model for the study of breast tumours; however, little is known regarding the transcriptome and DNA methylome landscapes of breast IP in tree shrews. In this research, we conducted whole-genome DNA methylation and transcriptome analyses of breast IP and normal mammary glands in tree shrews.MethodsDNA methylation profiles were generated from the whole-genome bisulfite sequencing and whole-transcriptome landscapes of IP and control groups of tree shrews through strand-specific library construction and RNA sequencing. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analyses and gene set enrichment analysis were performed. Spearman’s correlation analysis was used to identify statistical relationships between gene expression and DNA methylation.ResultsA genome-wide perspective of the epigenetic regulation of protein-coding genes in breast IP in tree shrews was obtained. The methylation levels at CG sites were considerably higher than those at CHG or CHH sites, and were highest in gene body regions. In total, 3,486, 82 and 361 differentially methylated regions (DMRs) were identified in the context of CG, CHG, and CHH, respectively, and 701 differentially methylated genes (DMGs) were found. Further, through transcriptomic analysis, 62 differentially expressed genes, 50 long noncoding RNAs, and 32 circular RNAs were identified in breast IP compared to normal mammary glands. Correlation analysis between the DNA methylation and transcriptome data revealed that 25 DMGs were also differentially expressed genes, among which the expression levels of 9 genes were negatively correlated with methylation levels in gene body regions. Importantly, integrated analysis identified 3 genes (PDZ domain-containing 1, ATPase plasma membrane Ca2+ transporting 4 and Lymphocyte cytosolic protein 1) that could serve as candidates for further study of breast IP in tree shrews.ConclusionsThis research has unearthed the comprehensive landscape of the transcriptome and DNA methylome of spontaneous IP in tree shrews, as well as candidate tumorigenesis related genes in IP. These results will contribute to the use of tree shrews in animal models of breast tumours.

Fibroblast activation induced by common bile duct ligation in rats with obstructive jaundice

Objective To investigate the effect of common bile duct ligation on fibroblast activation in rats with obstructive jaundice. Methods Twenty-four male specific pathogen free (SPF) rats were randomly divided into sham-operated group and experimental group, with 12 rats in each group. All rats underwent common bile duct ligation. Rats The common bile duct in the experimental group was ligated with 3-0 silk thread and cut off. The rats in the two groups were sampled 2 and 7 days after operation. Enzyme-linked immunosorbent assay (ELISA) was used to detect the content of transforming growth factor-β1 (TGF-β1). Immunohistochemistry was used to detect the expression of TGF-β1 protein. The real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) was used to detect the expression of TGF-β1 gene. Western blotting was used to detect the expression of TGF-β1 protein. Results In sham-operated group, the structure of hepatic lobules was intact, and the hepatic sinuses were normal without congestion. In experimental group, the structure of hepatic lobules was disordered and the hepatic cords were dissociated. The level of serum TGF-β1 in the experimental group at 2nd day [(689.42±58.13) ng/L] and 7th day [(867.53±45.62) ng/L] was significantly higher than that in the sham-operated group [(519.92±32.41) ng/L and (536.50±41.29) ng/L, t=8.822 and 18.635, P<0.05]. The expression of TGF-β1 protein in liver tissues of experimental group at 2nd day [(6.53±1.29)%] and 7th day [(8.97±1.85)%] was significantly higher than that of sham-operated group [(1.17±0.24)% and (1.54±0.39)%, t=8.822 and 18.635, P<0.05]. The expression of TGF-β1 in liver tissues of experimental group at 2nd day [(0.89±0.14)%] and 7th day [(0.95±0.19)%] was significantly higher than that of sham-operated group [(0.52±1.32)% and (0.31±1.76)%, t=14.693 and 18.316, P<0.05]. The gray value of TGF-β1 protein expression in liver tissue of experimental group at 2nd day after operation (0.62±0.13) and 7th day after operation (0.78±0.10) was significantly higher than that of sham-operated group (0.21±0.05 and 0.23±0.06, t=10.197 and 16.337, P<0.05). Conclusion The expression of TGF-β1 in rats with obstructive jaundice induced by common bile duct ligation is significantly up-regulated, and the proliferation of biliary duct epithelial cells induces fibroblast activation. Key words: Common bile duct ligation; Obstructive jaundice; Fibroblast activation

Effect of decreased activity of 5’-adenosine monophosphate activated protein kinase on breast development in adolescent mice

Objective To investigate the effects of decreased 5’-activated protein kinase (AMPK) activity in mouse mammary epithelium on the proliferation of ductal epithelial cells and the development of teminal end bud (TEB) in adolescent mice. Methods AMPK DN transgenic mice were successfully constructed. The fourth pair of mammary gland tissues from the right abdomen of 10 WT and DN mice were stained by whole tissue staining and PCNA immunohistochemical staining. The duct coverage area, initial duct length, number of ductal branches per millimeter, percentage of ductal invasion length, terminal tip of mammary gland tissues of WT and DN mice were analyzed. TEB average quantity, average maximum area of TEB. The ratio of PCNA positive cells to the total number of glandular epithelial cells was calculated. Results At 5th week, the number of ductal branches per millimeter in DN mice and WT mice was (1.39±0.18) mm vs. (1.21±0.11) mm, the average number of TEB was (13.99±3.14) vs. (10.65±2.09) and the average maximum area of TEB was (0.104±0.014) mm2 vs. (0.082±0.013) mm2, respectively, with significant difference (t=2.698, 2.800, 3.642, P<0.05); at 6th week, the number of ductal branches per millimeter in DN mice and WT mice was (1.59±0.013) mm2, respectively. 31) vs. (1.41±0.34) mm, the average number of TEB (15.86±3.26) vs. (12.47±2.34), the average maximum area of TEB (0.118±0.017) mm2vs. (0.087±0.014) mm2, the difference was statistically significant (t=2.406, 2.671, 4.451, P<0.05). The percentage of PCNA positive cells in mammary epithelial cells of 5 w DN mice (86.47±4.67) was significantly higher than that of WT mice (65.32±3.87)%, and 6 w DN mice (65.32±3.87)%. The percentage of cells in WT group was significantly higher than that in WT group (85.37±4.35) (63.47±3.45)%. The difference was statistically significant (t=4.614, 12.474, P< 0.05). Conclusion The decrease of AMPK activity in mouse mammary epithelium can promote the proliferation of ductal epithelial cells and the development of TEBs in adolescent mice. Key words: Mouse mammary epithelial cells; Adolescence; 5’-activated protein kinase; Proliferation; Teminal end bud

Ductal Carcinoma in Situ (DCIS)

Ductal carcinoma in situ (DCIS) is noninvasive intraductal carcinoma of the breast and is defined as a malignant proliferation of ductal epithelial cells that are confined to the milk ducts. It is a nonobligate precursor of invasive breast cancer, but at present, there is no reliable method of predicting which lesions will invade in a given time frame. Historically, DCIS was an uncommon lesion; however, widespread use of screening mammography has resulted in a significant increase in the rate of detection, and DCIS now accounts for about 20% of all breast cancers in the United States. Current treatment options for DCIS include breast-conserving surgery (BCS) alone, BCS with radiotherapy (RT), BCS with endocrine therapy, BCS with both RT and endocrine therapy, mastectomy, and even bilateral mastectomy. There is currently concern about overtreatment of this lesion, but there are no reliable data regarding outcomes without treatment. Although survival is excellent with all standard treatments, local recurrence rates vary widely with various treatment options. Given the variety of options available, the goal of treatment is to tailor the management plan to the individual and optimize the balance of risks and benefits according to the values and priorities of the woman herself. This review contains 10 figures, 6 tables and 54 references. Key words: active surveillance, breast conservation, ductal carcinoma in situ, endocrine therapy, intraductal carcinoma, margins, mastectomy, radiation, recurrence, risk factors

Ductal Carcinoma in Situ (DCIS)

Ductal carcinoma in situ (DCIS) is noninvasive intraductal carcinoma of the breast and is defined as a malignant proliferation of ductal epithelial cells that are confined to the milk ducts. It is a nonobligate precursor of invasive breast cancer, but at present, there is no reliable method of predicting which lesions will invade in a given time frame. Historically, DCIS was an uncommon lesion; however, widespread use of screening mammography has resulted in a significant increase in the rate of detection, and DCIS now accounts for about 20% of all breast cancers in the United States. Current treatment options for DCIS include breast-conserving surgery (BCS) alone, BCS with radiotherapy (RT), BCS with endocrine therapy, BCS with both RT and endocrine therapy, mastectomy, and even bilateral mastectomy. There is currently concern about overtreatment of this lesion, but there are no reliable data regarding outcomes without treatment. Although survival is excellent with all standard treatments, local recurrence rates vary widely with various treatment options. Given the variety of options available, the goal of treatment is to tailor the management plan to the individual and optimize the balance of risks and benefits according to the values and priorities of the woman herself. This review contains 10 figures, 6 tables and 54 references. Key words: active surveillance, breast conservation, ductal carcinoma in situ, endocrine therapy, intraductal carcinoma, margins, mastectomy, radiation, recurrence, risk factors

Effects of the GLP-1 Receptor Agonist Dulaglutide on the Structure of the Exocrine Pancreas of Cynomolgus Monkeys.

Clinical and nonclinical studies have implicated glucagon-like peptide-1 (GLP-1) receptor agonist therapy as a risk factor for acute pancreatitis in patients with type 2 diabetes. Therefore, it is critical to understand the effect that dulaglutide, an approved GLP-1 receptor agonist, has on the exocrine pancreas. Dulaglutide 8.15 mg/kg (approximately 500 times the maximum recommended human dose based on plasma exposure) was administered twice weekly for 12 months to cynomolgus monkeys. Serum amylase and lipase activities were measured and 6 sections of each pancreas were examined microscopically. Ductal epithelial cell proliferation was estimated using Ki67 labeling. Dulaglutide administration did not alter serum amylase or lipase activities measured at the end of treatment compared to control values. An extensive histologic evaluation of the pancreas revealed no changes in the acinar or endocrine portions and no evidence of pancreatitis, necrosis, or pancreatic intraepithelial neoplasia. An increase in goblet cells noted in 4 of the 19 treated monkeys was considered an effect of dulaglutide but was not associated with dilation, blockage, or accumulation of mucin in the pancreatic duct. There was no difference in cell proliferation in ductal epithelium between control and dulaglutide-treated monkeys. These data reveal that chronic dosing of nondiabetic primates with dulaglutide does not induce inflammatory or preneoplastic changes in exocrine pancreas.

Helicobacter pylori and pancreatic diseases.

A possible role for Helicobacter pylori (H. pylori) infection in pancreatic diseases remains controversial. H. pylori infection with antral predomination leading to an increase in pancreatic bicarbonate output and inducing ductal epithelial cell proliferation could contribute to the development of pancreatic cancer via complex interactions with the ABO genotype, dietary and smoking habits and N-nitrosamine exposure of the host. Although the individual study data available so far is inconsistent, several meta-analyses have reported an increased risk for pancreatic cancer among H. pylori seropositive individuals. It has been suggested that H. pylori causes autoimmune pancreatitis due to molecular mimicry between H. pylori α-carbonic anhydrase (α-CA) and human CA type II, and between H. pylori plasminogen-binding protein and human ubiquitin-protein ligase E3 component n-recognin 2, enzymes that are highly expressed in the pancreatic ductal and acinar cells, respectively. Future studies involving large numbers of cases are needed in order to examine the role of H. pylori in autoimmune pancreatitis more fully. Considering the worldwide pancreatic cancer burden, as well as the association between autoimmune pancreatitis and other autoimmune conditions, a complete elucidation of the role played by H. pylori in the genesis of such conditions could have a substantial impact on healthcare.

TNF-Like Weak Inducer of Apoptosis (TWEAK) Promotes Beta Cell Neogenesis from Pancreatic Ductal Epithelium in Adult Mice

Aim/HypothesisThe adult mammalian pancreas has limited ability to regenerate in order to restore adequate insulin production from multipotent progenitors, the identity and function of which remain poorly understood. Here we test whether the TNF family member TWEAK (TNF-like weak inducer of apoptosis) promotes β-cell neogenesis from proliferating pancreatic ductal epithelium in adult mice.MethodsC57Bl/6J mice were treated with Fc-TWEAK and pancreas harvested at different time points for analysis by histology and immunohistochemistry. For lineage tracing, 4 week old double transgenic mice CAII-CreERTM: R26R-eYFP were implanted with tamoxifen pellet, injected with Fc-TWEAK or control Ig twice weekly and analyzed at day 18 for TWEAK-induced duct cell progeny by costaining for insulin and YFP. The effect of TWEAK on pancreatic regeneration was determined by pancytokeratin immunostaining of paraffin embedded sections from wildtype and TWEAK receptor (Fn14) deficient mice after Px.ResultsTWEAK stimulates proliferation of ductal epithelial cells through its receptor Fn14, while it has no mitogenic effect on pancreatic α- or β-cells or acinar cells. Importantly, TWEAK induces transient expression of endogenous Ngn3, a master regulator of endocrine cell development, and induces focal ductal structures with characteristics of regeneration foci. In addition, we identify by lineage tracing TWEAK-induced pancreatic β-cells derived from pancreatic duct epithelial cells. Conversely, we show that Fn14 deficiency delays formation of regenerating foci after Px and limits their expansion.Conclusions/InterpretationWe conclude that TWEAK is a novel factor mediating pancreatic β-cell neogenesis from ductal epithelium in normal adult mice.

In situ and intraductal epithelial proliferations of prostate: definitions and treatment implications

• High-grade prostatic intraepithelial neoplasia (HGPIN) is an intracellular proliferation of ductal epithelial cells. On its own, the presence of HGPIN does not warrant active intervention. • In contrast, intraductal carcinoma of prostate and prostatic ductal adenocarcinoma of prostate are markers of aggressive prostatic adenocarcinoma. • The presence of even small foci of these tumours on biopsy warrants immediate intervention, even in the absence of demonstrable invasive disease. • This second part of the review of in situ epithelial proliferations of the prostate looks at these conditions in more detail.

Anticancer activity of the ethanolic extract of Crateva nurvala bark against testosterone and MNU-induced prostate cancer in rats

AimIn the present study the anticancer activity of the ethanolic extract of Crateva nurvala bark was evaluated against testosterone and N-methyl-N-nitrosourea (MNU)-induced prostate cancer in male Wistar rats. MethodsProstate cancer was induced in rats by the injection of testosterone for 3 d followed by injection of the chemical carcinogen MNU for 1 week. The prostate cancer-induced rats were treated with the ethanolic extract of C. nurvala bark, and testosterone injection was also continued through the experimental period of 4 months. Biochemical estimations including prostatic acid phosphatase, lipid peroxidation, enzymic antioxidants and non-enzymic antioxidants activity were done in the prostate and seminal vesicle tissue homogenate. ResultsThere was a significant increase in the level of acid phosphatase and lipid peroxidation in prostate cancer-induced rats, and after treatment with C. nurvala extract a significant decrease in the level of acid phosphatase lipid peroxidation were observed. The enzymic and non-enzymic antioxidants were decreased in the prostate cancer induced group and after treatment they were restored to near normal values. Histopathological examination showed significant changes such as hyperplastic prostatic acini and malignant proliferation of ductal epithelial cells in the prostate and seminal vesicle of carcinogen induced rats. After treatment with C. nurvala extract normal and flow-dilated ducts and acini with regular epithelial lining were observed in the prostate and partially hyperplastic and partially flattered epithelium were observed in seminal vesicles. ConclusionThe ethanolic extract of C. nurvala has significant anticancer activity evaluated by in an in vivo model.

Combinatorial Human Progenitor Cell Transplantation Optimizes Islet Regeneration Through Secretion of Paracrine Factors

Transplanted human bone marrow (BM) and umbilical cord blood (UCB) progenitor cells activate islet-regenerative or revascularization programs depending on the progenitor subtypes administered. Using purification of multiple progenitor subtypes based on a conserved stem cell function, high aldehyde dehydrogenase (ALDH) activity (ALDH(hi)), we have recently shown that transplantation of BM-derived ALDH(hi) progenitors improved systemic hyperglycemia and augmented insulin secretion by increasing islet-associated proliferation and vascularization, without increasing islet number. Conversely, transplantation of culture-expanded multipotent-stromal cells (MSCs) derived from BM ALDH(hi) cells augmented total beta cell mass via formation of beta cell clusters associated with the ductal epithelium, without sustained islet vascularization. To identify paracrine effectors produced by islet-regenerative MSCs, culture-expanded BM ALDH(hi) MSCs were transplanted into streptozotocin-treated nonobese diabetic/severe combine immune deficient (SCID) mice and segregated into islet-regenerative versus nonregenerative cohorts based on hyperglycemia reduction, and subsequently compared for differential production of mRNA and secreted proteins. Regenerative MSCs showed increased expression of matrix metalloproteases, epidermal growth factor receptor (EGFR)-activating ligands, and downstream effectors of Wnt signaling. Regenerative MSC supernatant also contained increased levels of pro-angiogenic versus pro-inflammatory cytokines, and augmented the expansion of ductal epithelial but not beta cells in vitro. Conversely, co-culture with UCB ALDH(hi) cells induced beta cell but not ductal epithelial cell proliferation. Sequential transplantation of MSCs followed by UCB ALDH(hi) cells improved hyperglycemia and glucose tolerance by increasing beta cell mass associated with the ductal epithelium and by augmenting intra-islet capillary densities. Thus, combinatorial human progenitor cell transplantation stimulated both islet-regenerative and revascularization programs. Understanding the progenitor-specific pathways that modulate islet-regenerative and revascularization processes may provide new approaches for diabetes therapy.

Targeted Expression of GLI1 in the Salivary Glands Results in an Altered Differentiation Program and Hyperplasia

Hedgehog (Hh) signaling is a regulator of salivary gland morphogenesis, but its role in postnatal glands has only recently begun to be addressed. To examine the effects of deregulated Hh signaling in the salivary gland, we expressed the Hh effector protein GLI1, in salivary epithelial cells using both cytokeratin 5 and mouse mammary tumor virus (MMTV) transgenic systems. Ectopic pathway activation resulted in restrained acinar differentiation, formation of cystic lesions, and prominent appearance of ductal structures. Moreover, induced expression of GLI1 aids the formation of hyperplastic lesions, which closely resemble GLI1-induced changes in murine skin and mammary glands, suggesting that GLI1 targets cells with similar characteristics in different tissues. Furthermore, GLI1-expressing salivary epithelial cells are actively dividing, and GLI1-induced lesions are proliferative, an incident accompanied by enhanced expression of the Hh target genes, cyclin D1, and Snail. GLI1-induced salivary lesions regress after transgene withdrawal and become histologically normalized. Taken together, our data reveal the ability of GLI1 to modulate salivary acinar differentiation and to promote proliferation of ductal epithelial cells.

Dual roles for macrophages in ovarian cycle-associated development and remodelling of the mammary gland epithelium

Each ovarian cycle, the mammary gland epithelium rotates through a sequence of hormonally regulated cell proliferation, differentiation and apoptosis. These studies investigate the role of macrophages in this cellular turnover. Macrophage populations and their spatial distribution were found to fluctuate across the cycle. The number of macrophages was highest at diestrus, and the greatest number of macrophages in direct contact with epithelial cells occurred at proestrus. The physiological necessity of macrophages in mammary gland morphogenesis during the estrous cycle was demonstrated in Cd11b-Dtr transgenic mice. Ovariectomised mice were treated with estradiol and progesterone to stimulate alveolar development, and with the progesterone receptor antagonist mifepristone to induce regression of the newly formed alveolar buds. Macrophage depletion during alveolar development resulted in a reduction in both ductal epithelial cell proliferation and the number of alveolar buds. Macrophage depletion during alveolar regression resulted in an increased number of branch points and an accumulation of TUNEL-positive cells. These studies show that macrophages have two roles in the cellular turnover of epithelial cells in the cycling mammary gland; following ovulation, they promote the development of alveolar buds in preparation for possible pregnancy, and they remodel the tissue back to its basic architecture in preparation for a new estrous cycle.

Involvement of REG Iα protein in the regeneration of ductal epithelial cells in the minor salivary glands of patients with Sjögren's syndrome

The regenerating gene (Reg) was originally isolated from regenerating rat pancreatic islets and revealed recently to constitute a multi-gene family in humans. REG Ialpha protein is known to be overexpressed not only in various human inflammatory diseases but also in various experimental models of inflammation in animal tissues. However, its involvement in pathophysiology of the minor salivary gland (MSG) is not clear. We investigated REG Ialpha expression in the MSG of patients with primary Sjögren's syndrome (SS) and assessed its role in ductal epithelial cell proliferation in such tissues. Lip biopsy specimens were obtained from 40 patients with primary SS and examined using immunohistochemistry for REG Ialpha protein, Ki67 and single-strand DNA (ssDNA). The relationships among clinicopathological factors and expression of REG Ialpha protein, Ki67 and ssDNA in the MSG were then analysed. REG Ialpha protein was expressed rarely in ductal epithelial cells of the normal MSG but was apparently overexpressed in those of patients with SS. The labelling indices for both Ki67 and ssDNA in the ductal cells of the MSGs were significantly higher in SS patients than in controls. Moreover, these labelling indices were significantly higher in REG Ialpha-positive than in negative SS patients. REG Ialpha protein may play a role in the regeneration of ductal epithelial cells in the MSGs of patients with SS.

Nodal and lefty signaling regulates the growth of pancreatic cells

Nodal and its antagonist, Lefty, are important mediators specifying the laterality of the organs during embryogenesis. Nodal signals through activin receptors in the presence of its co-receptor, Cripto. In the present study, we investigated the possible roles of Nodal and Lefty signaling during islet development and regeneration. We found that both Nodal and Lefty are expressed in the pancreas during embryogenesis and islet regeneration. In vitro studies demonstrated that Nodal inhibits, whereas Lefty enhances, the proliferation of a pancreatic cell line. In addition, we showed that Lefty-1 activates MAPK and Akt phosphorylation in these cells. In vivo blockade of endogenous Lefty using neutralizing Lefty-1 monoclonal antibody results in a significantly decreased proliferation of duct epithelial cells during islet regeneration. This is the first study to decipher the expression and function of Nodal and Lefty in pancreatic growth. Importantly, our results highlight a novel function of Nodal-Lefty signaling in the regulation of expansion of pancreatic cells.

Nodal and Lefty signaling regulates the growth of pancreatic cells

Nodal and its antagonist, Lefty, are important mediators specifying the laterality of the organs during embryogenesis. Nodal signals through activin receptors in the presence of its co‐receptor, Cripto. In the present study, we investigated the possible roles of Nodal and Lefty signaling during islet development and islet regeneration. By using immunohistochemistry, RT‐PCR and Western blotting methods, we found that both Nodal and Lefty are expressed in the pancreas during embryogenesis and islet regeneration. Exposure to recombinant mouse Nodal (rmNodal) inhibited the proliferation of a pancreatic progenitor cell line, AR42J cells, and conversely, recombinant mouse Lefty‐1 (rmLefty‐1) stimulated the proliferation of these cells. We also present evidence that the proliferation of the pancreatic progenitor cell line induced by Lefty‐1 involves phosphorylation of MAPK, activation of Akt and Bcl‐2 upregulation. In vivo blockade of endogenous Lefty using neutralizing a Lefty‐1 monoclonal antibody results in a significantly decreased proliferation of duct epithelial cells suggesting that Lefty‐1 is necessary for epithelial cell expansion during islet regeneration. Together, our data provide evidence for a novel role of Nodal‐Lefty signaling during pancreatic development and islet regeneration.