PDZ-Domain Containing-2 (PDZD2) Drives the Maturity of Human Fetal Pancreatic Progenitor-Derived Islet-Like Cell Clusters With Functional Responsiveness Against Membrane Depolarization

Abstract

We recently reported the isolation and characterization of a population of pancreatic progenitor cells (PPCs) from early trimester human fetal pancreata. The PPCs, being the forerunners of adult pancreatic cell lineages, were amenable to growth and differentiation into insulin-secreting islet-like cell clusters (ICCs) upon stimulation by adequate morphogens. Of note, a novel morphogenic factor, PDZ-domain containing-2 (PDZD2) and its secreted form (sPDZD2) were ubiquitously expressed in the PPCs. Our goals for this study were to evaluate the potential role of sPDZD2 in stimulating PPC differentiation and to establish the optimal concentration for such stimulation. We found that 10(-9)M sPDZD2 promoted PPC differentiation, as evidenced by the upregulation of the pancreatic endocrine markers (PDX-1, NGN3, NEURO-D, ISL-1, NKX 2.2, NKX 6.1) and INSULIN mRNA. Inhibited endogenous production of sPDZD2 suppressed expression of these factors. Secreted PDZD2 treatment significantly elevated the C-peptide content of the ICCs and increased the basal rate of insulin secretion. However, they remained unresponsive to glucose stimulation, reflected by a minimal increase in GLUT-2 and GLUCOKINASE mRNA expression. Interestingly, sPDZD2 treatment induced increased expression of the L-type voltage-gated calcium channel (Ca(v)1.2) in the ICCs, triggering calcium ion influx under KCl stimulation and conferring an ability to secrete insulin in response to KCl. Pancreatic progenitor cells from 10- and 13-week fetal pancreata showed peak expression of endogenous sPDZD2, implying that sPDZD2 has a specific role in islet development during the first trimester. In conclusion, our data suggest that sPDZD2 promotes functional maturation of human fetal PPC-derived ICCs, thus enhancing its transplanting potentials.

Involvement of the mitochondrial pathway in bruceine D-induced apoptosis in Capan-2 human pancreatic adenocarcinoma cells

“…Therefore, PS exposure represents a useful target for evaluating apoptosis (11,12). To assess plasma membrane changes, cells were stained with Annexin V (which binds preferentially to PS in the presence of Ca 2+ ) and PI simultaneously.…”

Vitamin D and Vitamin A Receptor Expression and the Proliferative Effects of Ligand Activation of These Receptors on the Development of Pancreatic Progenitor Cells Derived from Human Fetal Pancreas

“…The human fetal pancreata used in these experiments were obtained by the Department of Obstetrics and Gynecology in the Prince of Wales Hospital at The Chinese University of Hong Kong [10,11] following surgical termination of pregnancy (STOP) by dilation and extraction at 9-15 weeks gestation, with informed consent. Ethical approval for the use of fetal tissue was obtained from the Clinical Research Ethnics Committee (CREC-2005.461).…”

“…Each experiment was performed using preparations from a single isolated fetal pancreas for pancreatic progenitor cell preparation, as previously described [10,11]. In brief, the pancreas was immersed in chilled RPMI 1640 medium and then minced and digested in 3 mg/ml collagenase P (Roche, Mannheim, Germany) at 37°C for 5 min.…”

“…The signals necessary for effective promotion of islet beta-cell development must be identified for stem cells therapy to become an effective treatment, or even a cure, for T1DM and a treatment option for type 2 diabetes mellitus (T2DM) [8,9]. Our laboratory has successfully isolated and characterized a population of fetal pancreatic progenitor cell (PPC) model from first trimester human fetal pancreas using a basic protocol developed for differentiating PPCs into insulin-secreting islet-like cell clusters (ICCs) [10,11]. Further identification of all the factors necessary for islet beta cell differentiation is required before translation of this work into clinical practice can be achieved.…”

Non-classical effects of vitamin D

“…Эти клетки-предшественники имели высокую спо-собность к пролиферации и дифференцировке при куль-тивировании в соответствующем дифференцирующем коктейле. Их дифференциация поддерживался морфоге-нами, или факторами роста, связанными с развитием ПЖ человека, такими как, например, PDZ домен-содержащий белок-2 [64] и АТ II, а также витамины А и D [65]. Витамин А является хорошо известным модулятором β-клеточной дифференцировки, а витамин D влияет на секрецию ин-сулина β-клетками; как витамин А, так и D влияют через гетеродимеризацию ретиноидного Х-рецептора [66].…”