Neural tube defects and impaired neural progenitor cell proliferation in Gβ1‐deficient mice

Heterotrimeric G proteins are well known for their roles in signal transduction downstream of G protein–coupled receptors (GPCRs), and both Gα subunits and tightly associated Gβγ subunits regulate downstream effector molecules. Compared to Gα subunits, the physiological roles of individual Gβ and Gγ subunits are poorly understood. In this study, we generated mice deficient in the Gβ1 gene and found that Gβ1 is required for neural tube closure, neural progenitor cell proliferation, and neonatal development. About 40% Gβ1^?/? embryos developed neural tube defects (NTDs) and abnormal actin organization was observed in the basal side of neuroepithelium. In addition, Gβ1^?/? embryos without NTDs showed microencephaly and died within 2 days after birth. GPCR agonist‐induced ERK phosphorylation, cell proliferation, and cell spreading, which were all found to be regulated by Gαi and Gβγ signaling, were abnormal in Gβ1^?/? neural progenitor cells. These data indicate that Gβ1 is required for normal embryonic neurogenesis. Developmental Dynamics 239:1089–1101, 2010. © 2010 Wiley‐Liss, Inc.     

Chitin induces upregulation of B7‐H1 on macrophages and inhibits T‐cell proliferation

Chitin is a highly abundant glycopolymer, which serves as structural component in fungi, arthropods and crustaceans but is not synthesized by vertebrates. However, vertebrates express chitinases and chitinase‐like proteins, some of which are induced by infection with helminths suggesting that chitinous structures may be targets of the immune system. The chitin‐induced modulations of the innate and adaptive immune responses are not well understood. Here, we demonstrate that intranasal administration of OVA and chitin resulted in diminished T‐cell expansion and Th2 polarization as compared with OVA administration alone. Chitin did not promote nor attenuate Th2 polarization in vitro. Chitin‐exposed macrophages inhibited proliferation of CD4⁺ T cells in a cell–cell contact‐dependent manner. Chitin induced upregulation of the inhibitory ligand B7‐H1 (PD‐L1) on macrophages independently of MyD88, TRIF, TLR2, TLR3, TLR4 and Stat6. Inhibition of T‐cell proliferation was largely dependent on B7‐H1, as the effect was not observed in cocultures with cells from B7‐H1‐deficient mice.     

Regulation of apoptotic cell death in the pyloric glands of the canine stomach

In gastrointestinal epithelia, apoptosis has been thought to play a part in the shedding of postmitotic cells into the lumen. However, we have found that apoptosis more frequently in the generative cell (G) zone (the lower one third of the pit) than in the luminal zone (the upper one third of the pit) and the gland zone in the canine pyloric gland. To analyse the regulation of apoptotic cell death in each zone, we labelled S-phase cells by single and repeated injections of bromodeoxyuridine (BrdU) IV at intervals of 8 h. We found that 30% of apoptoses in the G zone were flash-labelled by BrdU and might derive from cells in or just after the S phase. The incidence of apoptosis and mitotic index did not change significantly after repeated injections of BrdU until the 49-h point, when the incidence of apoptosis increased and the mitotic index decreased significantly in the G zone, while the incidence of apoptosis decreased in the luminal zone. The BrdU-induced increase of apoptosis and cell-cycle arrest at the 49-h point may be caused by enhanced DNA mispairs that are elicited by incorporation of BrdU, in particular using the template of BrdU incorporated DNA. Apoptosis in the luminal zone may be down-regulated by reduced cell production in the G-zone.     

Islets of Langerhans from prohormone convertase‐2 knockout mice show α‐cell hyperplasia and tumorigenesis with elevated α‐cell neogenesis

Antagonism of the effects of glucagon as an adjunct therapy with other glucose‐lowering drugs in the chronic treatment of diabetes has been suggested to aggressively control blood glucose levels. Antagonism of glucagon effects, by targeting glucagon secretion or disabling the glucagon receptor, is associated with α‐cell hyperplasia. We evaluated the influence of total glucagon withdrawal on islets of Langerhans using prohormone convertase‐2 knockout mice (PC2‐ko), in which α‐cell hyperplasia is present from a young age and persists throughout life, in order to understand whether or not sustained glucagon deficit would lead to islet tumorigenesis. PC2‐ko and wild‐type (WT) mice were maintained drug‐free, and cohorts of these groups sampled at 3, 12 and 18 months for plasma biochemical and morphological (histological, immunohistochemical, electron microscopical and image analytical) assessments. WT mice showed no islet tumours up to termination of the study, but PC2‐ko animals displayed marked changes in islet morphology from α‐cell hypertrophy/hyperplasia/atypical hyperplasia, to adenomas and carcinomas, these latter being first encountered at 6–8 months. Islet hyperplasias and tumours primarily consisted of α‐cells associated to varying degrees with other islet endocrine cell types. In addition to substantial increases in islet neoplasia, increased α‐cell neogenesis associated primarily with pancreatic duct(ule)s was present. We conclude that absolute blockade of the glucagon signal results in tumorigenesis and that the PC2‐ko mouse represents a valuable model for investigation of islet tumours and pancreatic ductal neogenesis.     

Pseudomesotheliomatous carcinoma of the pleura: an autopsy case of metastasis from a G‐CSF‐producing anaplastic carcinoma of the pancreas

Pseudomesotheliomatous carcinoma is a malignant tumor that extends along the pleura mimicking malignant mesothelioma. An 81‐year‐old male patient presented to our hospital with epigastralgia, and abdominal computed tomography (CT) showed a 36‐mm tumor in the pancreatic tail. The laboratory data revealed a high leukocyte count (>44 000/μL). Chest CT showed left pleural thickening with pleural effusion. The cancer showed a poor response to chemotherapy, and the patient died of respiratory failure at 5 months after the onset of disease. Autopsy showed solid tumor with hemorrhage, measuring 6 cm in diameter, in the pancreatic tail, with wide invasion to the stomach, left adrenal gland, spleen, and diaphragm. The left pleura, which was circumferentially thickened by the involved tumor, macroscopically resembled pleural mesothelioma. Histologically, the primary pancreatic tumor was diagnosed as anaplastic carcinoma, due to the absence of glandular structures or other features that would indicate a definite direction of differentiation. The primary lesion and carcinoma involving the left pleura were all positive for G‐CSF. We recently experienced an autopsy case of G‐CSF‐producing anaplastic carcinoma with pseudomesotheliomatous spread.     

Florid basal cell hyperplasia of the prostate

Florid basal cell hyperplasia of the prostate is an uncommon proliferative condition, most often associated with adenomatous hyperplasia. It is considered a benign lesion although confusion with prostatic cancer is possible when one is not familiar with the histopathological appearance. We report another two cases of the glandular type of basal cell hyperplasia with immunohistochemical findings. Both lesions were composed of crowded and rather small glands with piling up of basaloid cells. They showed immunohistochemical positivity for high molecular weight cytokeratin 34βE12, confirming their relationship with basal cells. We detected focal positivity of these basal cells for α-smooth muscle actin, suggesting myoepithelial differentiation. Paucity of actin-positive smooth muscle cells in the stroma was noticed. One of the lesions showed some mild cytological atypia with prominent nucleoli and increased mitotic activity.     

Hepatoid adenocarcinoma of the stomach with multi-nucleated giant cell proliferation in a 100-year-old man

Few cases of gastric carcinoma with infiltrating multi-nucleated giant cells (MGCs) have been reported, and giant cells infiltrating the gastric carcinoma were previously described as osteoclast-like giant cells (OGCs). However, hepatoid adenocarcinomas have never been reported previously, and the present case is extremely rare. A 100-year-old Japanese man with gastralgia was found to have a mass in his gastric body. Histological examination showed a poorly differentiated adenocarcinoma with infiltration of MGCs. Vascular and lymphatic invasion were noted but there were no metastases. Almost all the tumor comprised cells with hepatoid-like features. The MGCs proliferated, with infiltration of lymphoid cells. A few MGCs contained mucous material in their cytoplasm, indicating these were foreign-body giant cells. Immunohistochemically, the hepatoid-like components were positive for AFP, and staining with polyclonal antibodies against carcinoembryonic antigen (CEA) showed the canalicular pattern. We concluded that this component was hepatoid adenocarcinoma. The MGCs were positive for CD68, and surrounding infiltrating lymphoid cells were diffusely positive for CD3. Infiltration of MGCs in gastric cancer may represent a cellular immune response against gastric cancer invasion. Further studies are required to elucidate the etiology of MGCs in gastric cancer.     

Chronic caffeine intake increases androgenic stimuli,epithelial cell proliferation and hyperplasia in rat ventral prostate

Coffee intake has been associated with a low risk of developing cancer, including prostate cancer, which is one of the most commonly diagnosed cancer in men. However, few studies have evaluated the chronic effects of caffeine, which is the most abundant methylxanthine in coffee, on prostate morphology and physiology. In the present study, we investigated the effects of chronic, low‐dose caffeine intake on rat prostate morphology from puberty to adulthood. Five‐week‐old male Wistar rats were randomized into two experimental groups: caffeine‐treated (20 ppm in drinking water, n = 12) and control (n = 12). The ventral and dorsolateral prostates were dissected, weighted and submitted to morphological, morphometrical and immunohistochemical analysis of cellular proliferation, apoptosis and androgen receptor (AR) tissue expression. The testosterone (T) and dihydrotestosterone (DHT) concentrations were measured in the plasma. Our results show that caffeine intake increased the concentrations of T and DHT, organ weight, epithelial cell proliferation and AR tissue expression in the ventral prostatic lobe. All the ventral prostates from the caffeine‐treated animals presented various degrees of epithelial and stromal hyperplasia. Our results suggest that chronic caffeine intake from puberty increases androgenic signalling and cell proliferation in the rat prostate gland and can be related to the development of benign prostatic hyperplasia.     

Human leucocyte antigen‐G 14‐bp InDel polymorphism and oral squamous cell carcinoma risk in Chinese Han population: A case–control study

Human leucocyte antigen‐G (HLA‐G) is a nonclassical HLA class I molecule involved in tumour immune escape. The purpose of this study was to investigate the association between the 14‐bp insertion/deletion (InDel) polymorphism in the 3′ untranslated region (3′‐UTR) of HLA‐G gene and oral squamous cell carcinoma (OSCC) risk in Chinese Han population (216 cases and 193 healthy controls), and furthermore, to evaluate serum soluble HLA‐G (sHLA‐G) levels in the OSCC patients. Our results demonstrated that the Ins allele was significantly less frequent in the OSCC patients than that in the healthy controls (odds ratio [OR] = 0.75; 95% confidence interval [CI]: 0.57–0.99; p = 0.040). Distribution of the 14‐bp genotypes in the OSCC patients and the healthy controls revealed that the Ins/Ins genotype was associated with decreased OSCC risk in both the codominant model (Ins/Ins versus Del/Del; OR = 0.57; 95% CI = 0.33–0.99; p = 0.044) and the log‐additive model (OR = 0.76; 95% CI: 0.58–0.99; p = 0.044). The serum sHLA‐G level was significantly higher in the OSCC patients than those in the healthy controls (p < 0.001). Receiver operating characteristic (ROC) curve revealed the valuable diagnostic value of sHLA‐G for OSCC detection, with an area under the ROC curve (AUC) of 0.891 (95% CI: 0.856–0.925, p < 0.001). The OSCC patients with Ins/Ins genotype had lower serum sHLA‐G levels than those with Ins/Del and Del/Del genotypes (p = 0.015). Furthermore, serum sHLA‐G levels were significantly increased with the increasing TNM stages of the OSCC patients (p = 0.017). Our findings revealed that the HLA‐G 14‐bp InDel polymorphism might be a genetic risk factor for OSCC susceptibility, and the serum sHLA‐G may act as a promising biomarker for noninvasive diagnosis of OSCC.     

Granulocyte colony‐stimulating factor (G‐CSF) plays an important role in immune complex‐mediated arthritis

Neutrophils are an abundant cell type in many chronic inflammatory diseases such as rheumatoid arthritis (RA); however, their contribution to the pathology of RA has not been widely studied. A key cytokine involved in neutrophil development and function is granulocyte‐colony stimulating factor (G‐CSF). In this study we used the K/BxN serum‐transfer arthritis (STA) model, mimicking the effector phase of RA, to investigate the importance of G‐CSF in arthritis development and its relation to neutrophils. Here, we show for the first time in this model that G‐CSF levels are increased both in the serum and in inflamed paws of arthritic mice and importantly that G‐CSF blockade leads to a profound reduction in arthritis severity, as well as reduced numbers of neutrophils in blood. Moreover, CXCL1 and CXCL2 levels in the arthritic joints were also lowered. Our data demonstrate that G‐CSF is a pivotal driver of the disease progression in the K/BxN STA model and possibly acts in part by regulating neutrophil numbers in the circulation. Therefore, our findings suggest that G‐CSF might be a suitable target in RA, and perhaps in other immune complex‐driven pathologies.     

Arginase‐1 is neither constitutively expressed in nor required for myeloid‐derived suppressor cell‐mediated inhibition of T‐cell proliferation

Although previous reports suggest that tumor‐induced myeloid‐derived suppressor cells (MDSC) inhibit T cells by L‐arginine depletion through arginase‐1 activity, we herein show that arginase‐1 is neither inherently expressed in MDSC nor required for MDSC‐mediated inhibition. Employing Percoll density gradients, large expansions of MDSC in the bone marrow of tumor‐bearing mice were isolated and demonstrated potent inhibition in T‐cell proliferation activated by TCR‐ligation, Concanavalin A, PMA plus ionomycin, or IL‐2. Despite demonstrating characteristic immunosuppressive capacity, these MDSC exhibit no arginase‐1 expression and/or exert their inhibitory effects independent of arginase‐1 activity. However, arginase‐1 expression in MDSC can be induced by exposure to TCR‐activated T cells or their culture medium, but not T cells activated by other means or growing tumor cells. Further investigation reveals multiple cytokines secreted by TCR‐activated T cells as orchestrating two signaling‐relay axes, IL‐6‐to‐IL‐4 and GM‐CSF/IL‐4‐to‐IL‐10, leading to arginase‐1 expression in MDSC. Specifically, IL‐6 signaling increases IL‐4R, enabling IL‐4 to induce arginase‐1 expression; similarly, GM‐CSF in concert with IL‐4 induces IL‐10R, allowing IL‐10‐mediated induction. Surprisingly, our study indicates that induction of arginase‐1 expression is not conducive to the critical MDSC‐mediated inhibition toward T cells, which is rather dependent on direct cell contacts undiminished by PD‐L1 blockade or SIRPα deficiency.     

Litomosoides sigmodontis induces TGF‐β receptor responsive,IL‐10‐producing T cells that suppress bystander T‐cell proliferation in mice

Helminth parasites suppress immune responses to prolong their survival within the mammalian host. Thereby not only helminth‐specific but also nonhelminth‐specific bystander immune responses are suppressed. Here, we use the murine model of Litomosoides sigmodontis infection to elucidate the underlying mechanisms leading to this bystander T‐cell suppression. When OT‐II T cells specific for the third‐party antigen ovalbumin are transferred into helminth‐infected mice, these cells respond to antigen‐specific stimulation with reduced proliferation compared to activation within non‐infected mice. Thus, the presence of parasitic worms in the thoracic cavity translates to suppression of T cells with a different specificity at a different site. By eliminating regulatory receptors, cytokines, and cell populations from this system, we provide evidence for a two‐staged process. Parasite products first engage the TGF‐β receptor on host‐derived T cells that are central to suppression. In a second step, host‐derived T cells produce IL‐10 and subsequently suppress the adoptively transferred OT‐II T cells. Terminal suppression was IL‐10‐dependant but independent of intrinsic TGF‐β receptor‐ or PD‐1‐mediated signaling in the suppressed OT‐II T cells. Blockade of the same key suppression mediators, i.e. TGF‐β‐ and IL‐10 receptor, also ameliorated the suppression of IgG response to bystander antigen vaccination in L. sigmodontis‐infected mice.     

Gastrin has a specific proliferative effect on the rat enterochromaffin‐like cell,but not on the parietal cell: A study by elutriation centrifugation

Gastrin has a general growth‐promoting effect on gastric oxyntic mucosa, and a more pronounced one on the enterochromaffin‐like (ECL) cell. Whether gastrin has a proliferative effect on the parietal cell lineage beyond the general effect is uncertain. Hypergastrinaemia was evoked in rats using pantoprazole (group II: 100 μmol kg^–1, group III: 400 μmol kg^–1) for 45 days. Plasma gastrin was 43 ± 8 pmol L^–1 (control), 283 ± 54 pmol L^–1 (group II) and 577 ± 63 pmol L^–1 (group III). Gastric mucosal cells were isolated and fractionated by elutriation centrifugation. Total cell number, percentage and number of ECL and parietal cells, and histamine were determined in each fraction. The number of mucosal cells increased 1.5‐fold in both hypergastrinaemic groups. Enterochromaffin‐like cell content was 2.6 ± 0.5% (control), 6.0 ± 0.6% (group II) and 9.0 ± 0.8% (group III). Histamine concentration in oxyntic mucosal cells rose similarly. The size of the ECL cells was 8.5 ± 0.1 μm (control), 10.8 ± 0.2 μm (group II) and 12.1 ± 0.2 μm (group III), and the increased size was confirmed by shifted distribution in elutriation fractions. Histamine per ECL cell increased with cell size. The number of parietal cells increased parallel to the total number of mucosal cells (1.5‐fold). Parietal cell size and percentage, assessed by image analysis and distribution in elutriation fractions, were unchanged after pantoprazole dosing. Gastrin has a pronounced, concentration‐dependent specific trophic effect on ECL cells and a general proliferative effect on gastric mucosa, including parietal cells.     

Multifocal nodular oncocytic hyperplasia of bilateral parotid glands: A case report with a histological variant of clear cells

A case of multifocal nodular oncocytic hyperplasia (MNOH) of the bilateral parotid gland is presented. An 80-year-old woman was admitted to hospital because of painless swellings in bilateral parotid regions. Histologically, the nodular lesion had incomplete capsules and engulfed the surrounding parotid gland at the periphery. The lesions were mostly composed of clear cells, while the peripheries of the lesions had typical oncocytic cells with abundant fine granules. The histological existence of the clear cell component in the lesions led to misdiagnoses of other clear cell neoplasms. However, this case had multiple nodules in bilateral glands. No evidence of malignant histological findings was found. Moreover, the clear cells, as well as the oncocytic cells, were demonstrated to have mitochondria and glycogen in their cytoplasm using special staining. Based on these findings, the diagnosis of this case was MNOH in the parotid gland. We also discuss the differential diagnosis for clear cell lesions.