TGF-β-induced phosphorylation of Akt and Foxo transcription factors negatively regulates induced regulatory T cell differentiation

Transforming growth factor-β (TGF-β) is a pivotal cytokine in the differentiation of regulatory T cells, and Foxo transcription factors positively regulate this process. On the other hand, the function of Foxo transcription factors is negatively regulated by PI3K/Akt signaling, which is activated by TGF-β in many types of cells; yet the role of TGF-β in Akt activity and its downstream substrates in CD4⁺ T cells, including Foxo transcription factors, remains to be determined. Herein, we demonstrate that TGF-β selectively induces Akt phosphorylation at Ser473 but not at Thr308 in a class I_A PI3K-dependent manner in CD4⁺ T cells, resulting in the phosphorylation and inhibition of Foxo transcription factors and negatively regulating the differentiation of induced regulatory T cells (iTregs). These observations reveal a novel negative regulatory mechanism involving Akt and Foxo transcription factors induced by TGF-β in the iTreg differentiation process.

Abstract 4036: Prognostic value of infiltrating immune cell profiling in lung adenocarcinoma

Neoplastic cancer cells and cancer stroma (including infiltrating immune cells) determine the biology and prognosis of cancer. Various types of adaptive and innate immune cells are known to infiltrate the cancer stroma. However, the patterns and spatial distribution of immune cell infiltration as well as their association with tumor histology remain poorly understood. To address these issues, we comprehensively analyzed the infiltrating immune cells present in lung adenocarcinoma. The principal types of both adaptive and innate infiltrating immune cells were immunohistochemically evaluated in the predominant histological components of 111 lung adenocarcinomas. The same analysis was also carried out on 143 samples of histological subtypes making up more than 20% of tumors. As a result, plasma cells and B cells with interfollicular distribution were almost exclusively observed in invasive histological subtypes, while increased number of mast cells were observed in noninvasive histological subtypes. Cluster analysis revealed four distinct immunosubtypes: those characterized by high CD8/CD3 ratios with low stromal cellularity (CD8 subtype), those with increased mast cell numbers (mast cell subtype), those with increased macrophage/DC infiltration with variable amounts of T cell infiltration (mϕ/DC subtype), and those with increased plasma cell infiltration in addition to increased macrophage/DC infiltration and variable increases in other infiltrating immune cells (T cells, Tregs, pDCs, and neutrophils) (plasma cell subtype). These immunosubtypes correlated with histological subtypes. Univariate and multivariate analyses identified the plasma cell subtype as an independent negative prognostic factor. Furthermore, we found that these plasma cells may be one of the major producers of immunosuppressive cytokine IL-35 in cancer stroma. Consequently, comprehensive immunohistochemistry-based profiling of infiltrating immune cells has potential as a powerful method for analyzing the cancer stroma of various cancer tissues.

Citation Format: Yutaka Kurebayashi, Katsura Emoto, Yuichiro Hayashi, Ikuo Kamiyama, Takashi Ohtsuka, Hisao Asamura, Michiie Sakamoto. Prognostic value of infiltrating immune cell profiling in lung adenocarcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4036.

Comprehensive Immune Profiling of Lung Adenocarcinomas Reveals Four Immunosubtypes with Plasma Cell Subtype a Negative Indicator

Neoplastic cancer cells and cancer stroma (including infiltrating immune cells) determine the biology and prognosis of cancer. Various types of adaptive and innate immune cells are known to infiltrate the cancer stroma. However, the patterns and spatial distribution of immune cell infiltration as well as its association with tumor histology remain poorly understood. To address these issues, we comprehensively analyzed the infiltrating immune cells present in lung adenocarcinoma. The principal types of both adaptive and innate infiltrating immune cells were immunohistochemically evaluated in the predominant histologic components of 111 lung adenocarcinomas. The same analysis was also carried out on 143 samples of histologic subtypes making up more than 20% of tumors. As a result, plasma cells and B cells with interfollicular distribution were almost exclusively observed in invasive histologic subtypes, while an increased number of mast cells were observed in noninvasive histologic subtypes. Cluster analysis revealed four distinct immunosubtypes (CD8, mast cell, macrophage/dendritic cell, and plasma cell subtypes) based on the infiltrating immune cell profiles. These immunosubtypes correlated with histologic subtypes, and univariate and multivariate analyses identified the plasma cell subtype as an independent negative prognostic factor. These plasma cells may be one of the major producers of the immunosuppressive cytokine IL35 in cancer stroma.

Polyacrylamide backbones for polyvalent bioconjugates using “post-click” chemistry

This paper reports the synthesis and application of acrylamide-type neoglycoconjugates interacting with practical targets.

Recent advances in understanding the molecular mechanisms of the development and function of Th17 cells

IL-17-producing T helper (Th17) cells comprise a distinct Th subset involved in epithelial cell- and neutrophil-mediated immune responses against extracellular microbes. At the same time, Th17 cells play significant roles in the development of autoimmune diseases including rheumatoid arthritis and multiple sclerosis. Since the identification of Th17 cells approximately a decade ago, the molecular mechanisms of their differentiation have been intensively studied and a number of signaling cascades and transcription factors have been shown to be involved. Here, we review the current knowledge regarding the function of Th17 cells in vivo as well as several key concepts for the molecular mechanisms of Th17 differentiation. We also discuss the emerging roles of phosphoinositide 3-kinase (PI3K), mammalian target of rapamycin complex 1 (mTORC1) and hypoxia-inducible factor 1 (HIF-1) in the differentiation of Th17 cells.

[Esophageal involvement in a case of eosinophilic gastroenteritis]

A 43-year-old woman presented with severe diarrhea and vomiting in addition to abdominal distension and dysphagia which had persisted for a month. Endoscopic biopsies revealed a significant eosinophilic infiltration in the mucosal layer of the esophagus, duodenum and ileum, yielding a diagnosis of eosinophilic gastroenteritis (EG) with esophageal involvement. The endoscopic examination of esophageal lesion in this case showed linear fissures and concentric rings, both of which are characteristic findings observed in eosinophilic esophagitis (EE). This suggests that these characteristic endoscopic findings in EE can also be applied to the results of endoscopic examinations for esophageal involvement in EG.

PI3K-Akt-mTORC1-S6K1/2 axis controls Th17 differentiation by regulating Gfi1 expression and nuclear translocation of RORγ

The PI3K-Akt-mTORC1 axis contributes to the activation, survival, and proliferation of CD4(+) T cells upon stimulation through TCR and CD28. Here, we demonstrate that the suppression of this axis by deletion of p85α or PI3K/mTORC1 inhibitors as well as T cell-specific deletion of raptor, an essential component of mTORC1, impairs Th17 differentiation in vitro and in vivo in a S6K1/2-dependent fashion. Inhibition of PI3K-Akt-mTORC1-S6K1 axis impairs the downregulation of Gfi1, a negative regulator of Th17 differentiation. Furthermore, we demonstrate that S6K2, a nuclear counterpart of S6K1, is induced by the PI3K-Akt-mTORC1 axis, binds RORγ, and carries RORγ to the nucleus. These results point toward a pivotal role of PI3K-Akt-mTORC1-S6K1/2 axis in Th17 differentiation.

Dynamic regulation of Th17 differentiation by oxygen concentrations

Naive CD4(+) T cells are activated by antigen-presenting cells (APCs) and differentiate into distinct types of helper T (T(h)) cells in the lymph node or spleen. Oxygen (O(2)) tension is generally low in these secondary lymphoid tissues compared with the bloodstream or atmosphere. However, the effect of changes in O(2) concentration on the differentiation of T(h) cells remains unclear. Here, we established a novel model of T(h)-cell differentiation, which mimics physiological O(2) conditions. We primed naive CD4(+) T cells under 5% O(2), which has been observed in the lymph node or spleen and reoxygenated under normoxia that mimicked the O(2) concentration in blood. In this model, the differentiation of T(h)17 cells, but not T(h)1 or iTreg cells, was enhanced. Under the condition of 5% O(2), mammalian target of rapamycin complex 1 (mTORC1) was activated and led to the stabilization of hypoxia-inducible factor 1α (HIF-1α) in T(h)17 cells. The activation of mTORC1 and the acceleration of T(h)17-cell differentiation, which occurred when cells were primed under 5% O(2), were not observed in the absence of HIF-1α but were accelerated in the absence of von Hippel-Lindau tumor suppressor protein (vHL), a factor critical for HIF-1α degradation. Thus, a positive feedback loop between HIF-1α and mTORC1 induced by hypoxia followed by reoxygenation accelerates T(h)17-cell differentiation.

A selective, high affinity 5-HT 2B receptor antagonist inhibits visceral hypersensitivity in rats

BACKGROUND

RS-127445 is a selective, high affinity 5-HT(2B)receptor antagonist. We investigated whether 5-HT(2B)receptor antagonists can reduce colonic visceral hypersensitivity caused by restraint stress or by proximal colonic inflammation.

METHODS

Visceral hypersensitivity was induced in rats by either restraint stress or injection of 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) into the proximal colon. Restraint stress produced a significant increase in numbers of abdominal contractions evoked by colorectal distension (CRD), measured as a quantitative index of visceral nociception in rats. Seven days after TNBS injection, the pain threshold to CRD at the non-inflamed distal colon, that was determined as the minimum pressure required to evoke abdominal cramp, was significantly decreased. The effect of RS-127445 on visceral hypersensitivity was assessed in either naïve or TNBS-treated rats.

KEY RESULTS

Oral administration of a selective, high affinity 5-HT(2B)receptor antagonist, RS-127445, significantly inhibited visceral hypersensitivity provoked by restraint stress (35 to 74% inhibition at 1 to 10 mg kg(-1)). Oral RS-127445 produced a significant suppression of TNBS-induced visceral hypersensitivity (15 to 62% inhibition at 3 to 30 mg kg(-1)), although it was without significant effect on the visceral nociceptive threshold of naïve rats. RS-127445 (1 to 30 mg kg(-1), p.o.) also dose-dependently reduced the restraint stress-induced defecation in naïve and TNBS-treated rats.

CONCLUSIONS & INFERENCES

These results suggest that 5-HT(2B)receptors are involved in signaling from the colon in rats in which there is visceral hypersensitivity and that a selective 5-HT(2B)receptor antagonist could have therapeutic potential for the treatment of gut disorders characterized by visceral hypersensitivity.

Synthesis and pharmacological activities of novel bicyclic thiazoline derivatives as hepatoprotective agents II. (7-Alkoxycarbonyl-2,3,5,6-tetrahydropyrrolo[2,1-b]thiazol-3-ylidend) acetamid derivatives

A series of exomethylenic bicyclic thiazoline derivatives (3a--i) was synthesized and evaluated for hepatoprotective activity against galactosamine-induced and monoclonal antibody-induced acute liver injuries in rats. The structure-activity relationships were investigated. Among the compounds synthesized, N-methyl-(7-isopropoxy-carbonyl-6,6-dimethyl-2,3,5,6- tetrahydropyrrolo[2,1-b]thiazol-3-ylidene)acetamide (3i) exhibited the most potent hepatoprotective activity. This compound suppressed galactosamine-induced hepatic injury at 100 mg/kg by oral administration and further prevented monoclonal antibody-induced hepatic injury at 30 mg/kg by intraperitoneal injection, as judged from the changes in serum transaminase activities.

Synthesis and pharmacological activities of novel bicyclic thiazoline derivatives as hepatoprotective agents. I. 8-Ethoxycarbonyl-5,6-dihydrothiazolo[2,3-c][1,4]thiazine derivatives

A series of bicyclic thiazoline derivatives (4a-s) was synthesized and evaluated for hepatoprotective activity against galactosamine-induced and monoclonal antibody-induced acute liver injuries in rats. The structure-activity relationships were investigated. Among the compounds synthesized, ethyl 3-(N-methylcarbamoyl)-5,6-dihydrothiazolo[2,3-c][1,4]thiazin e-8- carboxylate (4p) exhibited remarkable hepatoprotective activity and lower toxicity. This compound suppressed galactosamine-induced hepatic injury at 100 mg/kg by gavage and further prevented monoclonal antibody-induced hepatic injury at 30 mg/kg by intraperitoneal injection, as evaluated by measuring changes in serum transaminase activities.

Species- and organ-specificity and expression of 105 kD liver cell membrane glycoprotein antigen during rat development

Species- and organ-specificity of a rat liver cell antigen recognized by a monoclonal antibody (MoAb) from a hybridoma clone RM-1 was investigated immunohistologically and immunoelectronmicroscopically. In rats, the MoAb reacted specifically with liver cell membrane, but not with other organs tested, including the brain, thymus, heart, lung, stomach, spleen, kidney, small and large intestines, testis and muscle. Furthermore, it was found that liver from the human, monkey, mouse, rabbit, guinea pig, dog, cat, cattle and chicken showed no specific reaction with this MoAb. The results indicated that the antigen was organ- and species-specific and designated as rat liver cell-specific membranous antigen (RLSA). RLSA was expressed scarcely along cell junctions of immature hepatocytes at the 19th day of pregnancy. This increased gradually, and was expressed along all surface membranes after birth.

Antisecretory and antiulcer effects of ebselen, a seleno-organic compound, in rats

The effects of ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-on), a metal-containing organic compound, on gastric secretion and gastric ulceration were examined in rats. Intraduodenal ebselen (30 to 300 mg/kg) significantly and dose-dependently inhibited gastric secretion in pylorus-ligated rats. Both aspirin- and water-immersion restraint stress-induced ulcers were significantly prevented by oral administration of ebselen at doses equivalent to the antisecretory doses. These results indicate that the antisecretory effect of ebselen underlies its antiulcer effect in these models.

Effect of DS-4574, a novel peptidoleukotriene antagonist with mast cell stabilizing action, on acute gastric lesions and gastric secretion in rats

DS-4574 is a peptidoleukotriene antagonist with mast cell stabilizing activity. In the present study, we studied the effects of this compound on gastric secretion and various acute gastric lesions in rats. Intraduodenal administration of DS-4574 at doses of 5 to 10 mg/kg significantly and dose-dependently inhibited gastric acid secretion in pylorus-ligated rats, but a further increase in the dose up to 50 mg/kg did not cause any further inhibition. Shay ulceration in response to pylorus ligation was dose-dependently prevented by DS-4574 (10-25 mg/kg, i.d.). Water-immersion restraint stress- and aspirin-induced gastric ulcers were also significantly prevented in a dose-related manner by oral pretreatment with DS-4574 (10-50 mg/kg). The lower doses of DS-4574 (1-10 mg/kg, p.o.) significantly and dose-dependently protected the gastric mucosa against the necrotizing action of either absolute ethanol or concentrated hydrochloric acid, indicating that this compound possesses a potent gastroprotective activity. These antiulcer and gastric protective effects of DS-4574 were more potent than those of cimetidine used as a reference drug. These findings suggest that DS-4574 is useful for peptic ulcer therapy, as well as for the therapy of various allergic diseases, including asthma.

Protective effect of 16,16-dimethyl prostaglandin E2 on isolated rat hepatocytes against complement-mediated immune attack

16,16-Dimethyl prostaglandin E2 was examined for its ability to inhibit complement-mediated in vitro hepatocytolysis by an antigen-antibody reaction. In the presence of fresh rat serum as a source of complement, 5-min culture of isolated rat hepatocytes with a monoclonal antibody against a rat liver-specific membranous antigen resulted in a marked, significant elevation in lactate dehydrogenase leakage into the culture medium. However, with heat-inactivated rat serum, such a reaction did not occur, indicating that the hepatocytolysis induced by the antibody was attributable to the membrane damaging action of complement activated by an antigen-antibody reaction. Pretreatment of the hepatocyte with 16,16-dimethyl prostaglandin E2 significantly suppressed the cytolytic reaction induced by the antibody in a concentration-dependent manner. These results show that 16,16-dimethyl prostaglandin E2 is capable of protecting isolated rat hepatocytes against the membrane-damaging insult of activated complement.

Protection by 16,16-dimethyl prostaglandin E2 and dibutyryl cyclic AMP against complement-mediated hepatic necrosis in rats

16,16-Dimethyl prostaglandin E2, a known cytoprotective agent, was examined for its ability to protect the liver against complement-mediated necrosis induced by an intravenous injection of a monoclonal antibody against a rat liver-specific antigen in rats. The hepatic injury induced by the antibody was characterized by (a) rapid development of numerous massive hemorrhagic foci of necrotic liver cells, (b) marked increases in serum liver enzyme activities and (c) pronounced reduction in the CH50 level, presumably as a result of complement consumption in the liver. Pretreatment with 16,16-dimethyl prostaglandin E2 at intraperitoneal doses of 20 and 100 micrograms/kg suppressed the hepatic injury, as evidenced by markedly mitigated liver-cell necrosis and much smaller increases in the serum-enzyme activities compared with the values in diseased control animals. The prostaglandin analogue failed to prevent serum complement consumption in response to the antibody injection or affect the CH50 level at the preinjury stage, indicating that neither complement inactivation nor interference with the antigen-antibody reaction was involved in the hepatic protection. The hepatoprotective doses of 16,16-dimethyl prostaglandin E2 produced a significant increase in liver cyclic AMP content in a dose-related manner. In addition, intravenous dibutyryl cyclic AMP at 3 and 10 mg/kg dose-dependently prevented histological and biochemical changes in the hepatic damage without altering the rate of reduction in serum complement activity. Like 16,16-dimethyl prostaglandin E2, dibutyryl cyclic AMP did not affect the preinjury CH50 level.(ABSTRACT TRUNCATED AT 250 WORDS)

Colonization of Helicobacter pylori in the gastric mucosa of Mongolian gerbils

Helicobacter pylori was orally inoculated into Mongolian gerbils. The organisms were able to colonize in the gastro-mucosal layer of the gerbils, especially in those gerbils which had mucosal lesions caused by indomethacin treatment. The pathological changes developed by H. pylori infection were restricted to the stomachs, and only slightly inflammatory cells were observed.

A rat model of acute liver necrosis induced by a monoclonal antibody to liver-specific antigen and complement

Acute massive hepatic injury was induced in rats by a monoclonal antibody against a rat liver-specific membrane antigen, and its histological characteristics were investigated. A single intravenous injection of murine ascites containing a monoclonal antibody produced numerous hemorrhagic foci of degenerated and necrotic liver cells predominantly in zones 1 (the periportal area) and 2 (the area of transition between the periportal zone and the perivenular zone) of the liver lobule within 10 min. Massive hepatocellular necroses were observed 1 hr later, but no inflammatory cell infiltration occurred in and around the necrotic foci. Immunohistological study demonstrated marked deposition of the third component of the complement system in the necrotic area. Serum complement activity was sharply decreased immediately after the injection of the antibody, suggesting that the hepatic necrosis is ascribable to a complement-mediated immune attack on the liver cell membrane induced by the antigen-antibody reaction. The hepatic necrosis in response to monoclonal-antibody injection did not progress to a chronic disease and healed almost completely, changing to scar tissues within 2 wk. Although it is not clear whether this hepatic injury has any clinical relevance, this antibody/complement model may be useful for investigating the cause and therapy of hepatic diseases such as fulminant hepatitis.

[Comparison of three methods for detecting Campylobacter pylori and measurement of human antibody titers against the whole organisms]

In order to detect Campylobacter pylori in the gastric mucosa, three different methods as 1) culture of the organisms, 2) immunostaining by monoclonal antibody against the cells, and 3) urease test were compared. In the disease group, positive % of each methods was 64, 75 and 74. However, positive % common to the three methods was only 48. The corresponding rate of culture and urease tests, and that of culture and staining methods was 81% and 60%, respectively. Therefore, it was concluded that urease test was a useful method, and that the three methods were necessary to confirm the existence of the organisms in the gastric mucosa. Total positive % of culture and staining methods in disease and control groups was 77 and 31, respectively, indicating that positive % of the disease group was much higher than that of the control group. Anti C. pylori titer was compared between culture-positive and culture-negative patients by ELISA. The titer of the former was significantly higher than that of the latter.

Antiulcer effects of 3-[[[2-(3,4-dimethoxyphenyl)ethyl] carbamoyl]methyl]-amino-N-methylbenzamide in experimental gastric and duodenal ulcers

Effects of 3-[[[2-(3,4-dimethoxyphenyl)ethyl]carbamoyl] methyl]-amino-N-methylbenzamide (DQ-2511), a newly synthesized compound, were evaluated using various types of experimental gastric and duodenal ulcers in rats. Pretreatment with DQ-2511, over the dose range 30-300 mg/kg p.o., resulted in a dose-related inhibition of water-immersion stress-, serotonin-, acetylsalicylic acid (ASA)-, indometacin-, ethanol-, and 2-deoxy-D-glucose(2DG) plus indometacin-induced gastric ulcers as well as cysteamine-induced duodenal ulcers. The antiulcer potencies of DQ-2511 were equal to or greater than those of H2-receptor antagonist cimetidine in these ulcer models except for ASA- and 2DG plus indometacin-induced ulcers. The rate of healing of chronic gastric ulcers induced by acetic acid was significantly accelerated by DQ-2511 (100 and 300 mg/kg p.o.) but not by the same doses of cimetidine. DQ-2511, at doses of 30 mg/kg p.o. and above, produced a significant decrease in gastric acid and pepsin output in pylorus-ligated rats. In anesthetized rats with acute gastric fistulae, 30 mg/kg i.v. of DQ-2511 significantly inhibited gastric acid secretion stimulated by 2DG, whereas it did not affect gastric hyperacidity evoked by either carbachol, histamine or pentagastrin. At effective antiulcer doses, this compound produced a sustained increase in gastric mucosal blood flow in conscious, restrained rats. Based on these observations, DQ-2511 is characterized as a new antiulcer compound with beneficial effects on both gastric aggressive and defensive factors. Furthermore, these results indicate a possible superiority of DQ2511 over cimetidine in regard to its antiulcer potency and spectrum.

Chemiluminescence and phagocytic responses of rat polymorphonuclear neutrophils to leptospires

The interaction of leptospires with polymorphonuclear neutrophils (PMN) was examined by the luminol-dependent chemiluminescence (CL) test. Whole blood CL changed in relation to the stage of leptospiral infection both in susceptible (SUS) and resistant (RES) rats. The intensity of CL grew with an increasing number of leptospires in the blood. CL responses were observed in isolated PMN upon exposure to living leptospires. In contrast, the same bacteria, having been inactivated by formalin, did not stimulate PMN. A variation was found in the CL response by different living strains of Leptospira. The CL intensity was arranged as follows: L. illini greater than L. biflexa greater than L. interrogans avirulent strains greater than L. interrogans virulent strains. The CL response was markedly enhanced by an opsonization of leptospires. Specific opsonization was shown to increase the rate of phagocytosis of leptospires with relation to the CL response.

Gastric cytoprotection by ebselen against the injury induced by necrotizing agents in rats

The gastric cytoprotective effect of ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one), a novel seleno-organic antioxidative agent, against the insults of necrotizing agents was investigated in rats. Either 0.6 N HCl or acidified ethanol (60% ethanol in 150 mmol/l HCl), given orally in a volume of 1 ml, produced linear hemorrhagic necroses in the gastric mucosa within 1 h. Pretreatment with ebselen at oral doses from 10 to 100 mg/kg significantly inhibited such lesion formation induced by either necrotizing agent in a dose-related manner, and the inhibition at the highest dose (100 mg/kg p.o.) was practically complete. Light microscopic analysis also confirmed that ebselen effectively prevented the formation of deep mucosal necrosis in response to the necrotizing agents. In addition, the protection by ebselen of gastric necrosis induced by either damaging agent was not affected by pretreatment of animals with indomethacin (5 mg/kg s.c.), indicating that the protective effect of this agent was not mediated by the mild irritation on the gastric mucosa. These results demonstrate that ebselen is a potent cytoprotective agent effectively preventing the gastric mucosal injury induced by necrotizing agents.