O-GlcNAcylation of ATG4B positively regulates autophagy by increasing its hydroxylase activity

Autophagy is a catabolic degradation process and maintains cellular homeostasis. And autophagy is activated in response to various stress conditions. Although O-GlcNAcylation functions a sensor for nutrient and stress, the relationship between O-GlcNAcylation and autophagy is largely unknown. Here, we identified that ATG4B is novel target for O-GlcNAcylation under metabolic stress condition. Treatment with PugNAc, an O-GlcNAcase inhibitor increased activation of autophagy in SH-SY5Y cells. Both bimolecular fluorescence complementation and immunoprecipitation assay indicated that OGT directly interacts with ATG4B in SH-SY5Y cells. We also found that the O-GlcNAcylated ATG4B was increased in autophagy activation conditions, and down-regulation of OGT reduces O-GlcNAcylation of ATG4B under low glucose condition. Furthermore, the proteolytic activity of ATG4B for LC3 cleavage was enhanced in PugNAc-treated cells. Taken together, these results imply that O-GlcNAcylation of ATG4B regulates autophagy activation by increasing its proteolytic activity under metabolic stress condition.

Potent suppression of both spontaneous and carcinogen-induced colitis-associated colorectal cancer in mice by dietary celastrol supplementation

Celastrol is an anti-inflammatory natural triterpenoid, isolated from the herb Tripterygium wilfordii or thunder god vine. Here, we define mechanisms mediating anti-inflammatory activity of celastrol and demonstrate efficacy of a dietary celastrol supplement for chemoprevention of inflammation-driven carcinogenesis in mice. Dietary celastrol (31.25 ppm in rodent diet from 8 weeks to 25 weeks of age) is well tolerated and protects against LPS-induced acute inflammation in C57BL/6 mice, potently suppressing LPS-induction of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, Interleukin (IL)-6 and IL-1β. To test whether dietary celastrol suppresses inflammation-driven colorectal cancer (CRC), we employed a unique model of spontaneous, inflammation-driven CRC in mice harboring a germ line deletion of the p27Kip1 gene and a T cell-specific deletion of Smad4 gene (Smad4co/co;Lck-crep27Kip1-/-or DKO), which develop severe intestinal inflammation and carcinogenesis as early as 3 months of age. Exposure of DKO mice to daily dietary celastrol (12.5 ppm in diet) from 6 weeks of age significantly suppressed development of colitis-associated CRC (CAC). Celastrol chemoprevention of CAC in this new model of intestinal neoplasia was associated with significant suppression of iNOS at 4 months of age, and iNOS, COX-2 and NFκB at 6 months of age, with significant reduction in inflammatory cytokines, IL-6 and IL-1β. Chemoprevetion of CAC by dietary celastrol was further confirmed in the model of azoxymethane (AOM) plus dextran sodium sulfate (DSS)-induced carcinogenesis in C57BL/6 mice. These data suggest the potential for celastrol as a safe and effective dietary supplement in the chemoprevention of CAC in humans.

Predicting Successful Phase Advancement and Regulatory Approval in Multiple Myeloma From Phase I Overall Response Rates

PURPOSE

Drug development in oncology is resource intensive, time consuming, and frequently unsuccessful. Here, we hypothesized that therapeutic benefit of published phase I studies of antimyeloma investigational agents was associated with advancement to phase II and future regulatory approval.

PATIENTS AND METHODS

Seventy four phase I trials that treated patients with multiple myeloma (n = 2,408) conducted from 2004 to 2015 were analyzed to assess drug safety, efficacy, phase advancement, and regulatory approval.

RESULTS

The median overall response rate (ORR) for all single-agent trials evaluated was 13.2%. However, the ORR in trials that advanced to phase II was 19%, whereas it was only 4% in trials that failed to advance. The median ORR was 23% for trials testing agents that were ultimately approved by the US Food and Drug Administration compared with only 8% for trials testing agents that were not approved (hazard ratio, 2.21; 95% CI, 2.01 to 2.61; P = .012). Importantly, the absolute number of phase I trials in multiple myeloma, but not the success rate, significantly increased over the period studied. The proportion of industry-sponsored trials also steadily increased over that same period. The ratio of initial dose to maximum tolerated dose was 0.29, suggesting that many patients were undertreated.

CONCLUSION

Investigational agents with higher ORRs in phase I trials were more likely to advance to phase II trials and achieve US Food and Drug Administration approval. Our results suggest that designing phase I trials to maximize the antimyeloma efficacy of a given compound may lead to more successful and cost-effective drug development.

Abstract 2647: TGF-β type I receptor inhibitor (TEW-7197) diminishes myeloma progression by multiple immunomodulatory mechanisms in combination with ixazomib

Background: Multiple myeloma (MM) is an incurable cancer of plasma cells. MM thrives in the bone marrow tumor microenvironment (TME) where several factors sustain MM growth and viability. TGF-β is a multi-functional cytokine elaborated by MM cells and by cells in the bone marrow (BM) TME. TGF-β stimulates MM progression through promotion of catabolic bone remodeling, IL-6 secretion and Th17 T cell development, which act in concert to induce osteolytic bone disease, immune suppression and myeloma progression. Therefore, we evaluated the anti-MM therapeutic potential of a small molecule inhibitor of the TGF-β type I receptor kinase (TβRI), TEW-7197, in combination with the proteasome inhibitor, ixazomib. Currently, TEW-7197 is being evaluated in phase I clinical trials in patients with solid tumors, and exposure to this agent is associated with an acceptable tolerability profile.

Methods: The preclinical immunocompetent 5T33MM model (C57BL/KaLwRij) was used to characterize the role of TGF-β signaling in the BM TME. Mice bearing 5T33MM cells expressing luciferase were treated with TEW-7197, ixazomib and the combination of TEW-7197 plus ixazomib daily for 3 weeks, and evaluated for MM growth by bioluminescence imaging (BLI). Cellular and molecular assays were performed in human RPMI8226 and U266 as well as murine 5T33MM cells via apoptosis, real-time PCR and Western blotting. Immunological assays were performed via immunohistochemistry and FACS analyses. Peripheral blood monoclonal protein concentration, M-spike, was measured by ELISA.

Results: TEW-7197 attenuated the growth and viability of human and murine MM cells by inducing apoptosis and it inhibited TGF-β-induced activation of Smad2/3 in MM cells in vitro. In our 5T33MM preclinical model, oral administeration of TEW-7197 as single agent inhibited MM progression as measured by peripheral blood monoclonal protein concentration and BLI before and after treatment. TEW-7197 also induced a decrease in mortality and an increase in body weight of mice bearing MM. TEW-7197 alone or combination with ixazomib also attenuated TGF-β activation of Smad2/3, reduced the expansion of CD11b+Gr-1+ myeloid derived suppressor cells (MDSCs) in BM TME, and diminished the population of Foxp3+ regulatory T cells (Treg) in the spleen. Combination therapy of TEW-7197 plus ixazomib prolonged survival and exhibited a synergistic anti-tumor effect when compared to either TEW-7197 or ixazomib alone by significant a reduction in both the M-spike and BLI.

Conclusion: Our data demonstrate that the small molecule inhibitor of the TβRI, TEW-7197, effectively modulate the MM TME and is associated with a potent anti-myeloma effect in an immunocompetent murine model of MM. These data provide a rationale for clinical evaluation of the combination therapy of ixazomib and TEW-7197 as a potential therapeutic strategy to improve outcomes in patients with MM.

Citation Format: Byung-Gyu Kim, Olga Sergeeva, George Luo, Sung Hee Choi, Zhenghong Lee, Seong-Jin Kim, John Letterio, Ehsan Malek. TGF-β type I receptor inhibitor (TEW-7197) diminishes myeloma progression by multiple immunomodulatory mechanisms in combination with ixazomib [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2647. doi:10.1158/1538-7445.AM2017-2647

Nedd4 Deficiency in Vascular Smooth Muscle Promotes Vascular Calcification by Stabilizing pSmad1

The nonosseous calcification process such as atherosclerosis is one of the major complications in several types of metabolic diseases. In a previous study, we uncovered that aberrant activity of transforming growth factor β (TGF-β) signaling pathway could contribute to the vascular smooth muscle cells' (VSMCs) calcification process. Also, we identified NEDD4 E3 ligase as a key suppressor of bone morphogenetic protein (BMP)/Smad pathway via a polyubiquitination-dependent selective degradation of C-terminal phosphorylated Smad1 (pSmad1) activated by TGF-β. Here, we further validated and confirmed the role of Nedd4 in in vivo vascular calcification progression. First, Nedd4 deletion in SM22α-positive mouse tissues (Nedd4^fl/fl ;SM22α-Cre) showed deformed aortic structures with disarranged elastin fibers at 24 weeks after birth. Second, vitamin D-induced aorta vascular calcification rate in Nedd4^fl/fl ;SM22α-Cre mice was significantly higher than their wild-type littermates. Nedd4^fl/fl ;SM22α-Cre mice showed a development of vascular calcification even at very low-level injection of vitamin D, but this was not exhibited in wild-type littermates. Third, we confirmed that TGF-β1-induced pSmad1 levels were elevated in Nedd4-deficient primary VSMCs isolated from Nedd4^fl/fl ;SM22α-Cre mice. Fourth, we further found that Nedd4^fl/fl ;SM22α-Cre mVSMCs gained mesenchymal cell properties toward osteoblast-like differentiation by a stable isotope labeling in cell culture (SILAC)-based proteomics analysis. Finally, epigenetic analysis revealed that methylation levels of human NEDD4 gene promoter were significantly increased in atherosclerosis patients. Collectively, abnormal expression or dysfunction of Nedd4 E3 ligase could be involved in vascular calcification of VSMCs by activating bone-forming signals during atherosclerosis progression. © 2016 American Society for Bone and Mineral Research.

Metabolic control of primed human pluripotent stem cell fate and function by the miR-200c-SIRT2 axis

A hallmark of cancer cells is the metabolic switch from oxidative phosphorylation (OXPHOS) to glycolysis, a phenomenon referred to as the 'Warburg effect', which is also observed in primed human pluripotent stem cells (hPSCs). Here, we report that downregulation of SIRT2 and upregulation of SIRT1 is a molecular signature of primed hPSCs and that SIRT2 critically regulates metabolic reprogramming during induced pluripotency by targeting glycolytic enzymes including aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, and enolase. Remarkably, knockdown of SIRT2 in human fibroblasts resulted in significantly decreased OXPHOS and increased glycolysis. In addition, we found that miR-200c-5p specifically targets SIRT2, downregulating its expression. Furthermore, SIRT2 overexpression in hPSCs significantly affected energy metabolism, altering stem cell functions such as pluripotent differentiation properties. Taken together, our results identify the miR-200c-SIRT2 axis as a key regulator of metabolic reprogramming (Warburg-like effect), via regulation of glycolytic enzymes, during human induced pluripotency and pluripotent stem cell function.

Randomised clinical trial: the efficacy and safety of oltipraz, a liver X receptor alpha-inhibitory dithiolethione in patients with non-alcoholic fatty liver disease

BACKGROUND

Oltipraz is a synthetic dithiolethione with an antisteatotic effect by inhibiting the activity of liver X receptor alpha (LXR-α). Recent studies demonstrated the disruptive role of oltipraz on LXR-α-dependent lipogenesis in hepatocytes and a high-fat diet mouse model.

AIM

To evaluate the efficacy and safety of oltipraz for reducing liver fat in subjects with non-alcoholic fatty liver disease (NAFLD).

METHODS

We performed a multicentre, double-blind, placebo-controlled, phase II study. Subjects with a liver fat >20% and hypertransaminasemia were randomised to the three groups: placebo (n = 22), 30 mg of oltipraz (n = 22) or 60 mg of oltipraz (n = 24) twice daily for 24 weeks. Changes in the liver fat from baseline to 24 weeks quantified using magnetic resonance spectroscopy were the primary outcome.

RESULTS

Compared with the placebo group (-3.2 ± 11.1%), absolute changes in the liver fat content increased in a dose-dependent manner: -7.7 ± 7.0% and -13.9 ± 10.7% for the low-dose and high-dose groups (P = 0.13 and P < 0.01). Per cent reduction in the liver fat content was also significantly greater in the high-dose group than in the placebo group (-34.6 ± 29.4% vs. -0.6 ± 62.9%, P = 0.046). Body mass indices (-1.0 ± 0.9% vs. -0.5 ± 1.4%, P = 0.04) significantly decreased in the high-dose group compared to the placebo group. However, absolute changes in insulin resistance, liver enzymes, lipids and cytokines were not significantly different among groups. The incidence of adverse events was comparable among groups.

CONCLUSIONS

Twenty-four-week oltipraz treatment significantly reduced the liver fat content in patients with NAFLD. Clinicaltrials.gov (NCT01373554).

Characteristics of extracellular cyclic AMP-dependent protein kinase as a biomarker of cancer in dogs

OBJECTIVE

Early and proper diagnosis of cancer is the most critical factor for the survival and treatment of veterinary cancer patients. In this study, we evaluated extracellular cyclic AMP-dependent protein kinase A (ECPKA) level in serum as a useful cancer biomarker in dogs.

METHODS

ECPKA levels were detected in sera from dogs with cancers (n = 48), benign tumours (n = 18), and non-tumour diseases (n = 102) as well as healthy control dogs (n = 54) utilizing enzyme-linked immunosorbent assay (ELISA).

RESULTS

Sera from dogs bearing various types of cancer exhibited markedly increased levels of ECPKA by up to 7.1-, 8.8-, and 10.9-fold compared with those from dogs harbouring benign tumours, dogs with non-tumour diseases, and healthy control dogs, respectively (P < .0001). In addition, serum ECPKA level did not show statistically significant correlation with gender, breed, or age of dogs or their non-cancerous disease conditions.

CONCLUSION

Our data strongly propose that detection of serum ECPKA level is a potential and specific diagnostic tool for cancer in dogs.

Effects of ileal digesta collection time on standardized ileal digestibility of amino acids in corn, soybean meal, and distiller's dried grains with solubles fed to growing pigs

The objective of this experiment was to determine the minimum collection time needed to obtain representative samples of ileal digesta from pigs fed different types of diets. Eight barrows with an initial BW of 34.6 kg (SD 2.1) were individually fitted with a T-cannula in the distal ileum and randomly allotted to a replicated 4 × 4 Latin square design with 4 diets and 4 periods per square. Three diets contained corn, soybean meal (SBM), or distiller's dried grains with solubles (DDGS) as the sole source of CP. An N-free diet was also prepared. All diets contained 0.5% chromic oxide as an indigestible marker. Equal meals were provided at 0800 and 2000 h. Ileal digesta samples were collected in 2-h intervals from 0800 to 2000 h during the last 3 d of each 7-d period. When pigs were fed the corn diet, the standardized ileal digestibility (SID) of most indispensable AA and dispensable AA increased and then decreased (quadratic, < 0.05) during each of the six 2-h periods. The SID of most AA were less ( < 0.05) if the ileal digesta samples were collected from 1800 to 2000 h or from 1600 to 2000 h compared with the SID values from the ileal samples collected over the entire 12-h period. When pigs were fed the SBM diet, the SID of Ile, Leu, Thr, Trp, Val, Ala, and Cys increased and then decreased (quadratic, < 0.05) but the SID of all other AA linearly decreased ( < 0.05) during the six 2-h periods. The SID of almost all AA were greater ( < 0.05) if the ileal samples were collected from 0800 to 1000 h, from 0800 to 1200 h, from 1000 to 1400 h, or from 0800 to 1400 h but less ( < 0.05) if collected from 1600 to 1800 h, from 1800 to 2000 h, from 1600 to 2000 h, or from 1400 to 2000 h compared with the SID values from the ileal samples collected over the entire 12-h period. When pigs were fed the DDGS-based diet, the SID of Ile, Leu, Lys, Phe, Trp, Val, and Tyr increased and then decreased (quadratic, < 0.05) during the six 2-h periods. The SID of most AA were less ( < 0.05) if the ileal samples were collected from 1800 to 2000 h compared with the SID values from the ileal samples collected over the entire 12-h period. In conclusion, diurnal variations in SID of AA in pigs indicate that 6 h of ileal sample collection starting 4 or 6 h after feeding may provide representative samples of ileal digesta from pigs fed different types of diets.

Inhibition of Pyruvate Dehydrogenase Kinase 2 Protects Against Hepatic Steatosis Through Modulation of Tricarboxylic Acid Cycle Anaplerosis and Ketogenesis

Hepatic steatosis is associated with increased insulin resistance and tricarboxylic acid (TCA) cycle flux, but decreased ketogenesis and pyruvate dehydrogenase complex (PDC) flux. This study examined whether hepatic PDC activation by inhibition of pyruvate dehydrogenase kinase 2 (PDK2) ameliorates these metabolic abnormalities. Wild-type mice fed a high-fat diet exhibited hepatic steatosis, insulin resistance, and increased levels of pyruvate, TCA cycle intermediates, and malonyl-CoA but reduced ketogenesis and PDC activity due to PDK2 induction. Hepatic PDC activation by PDK2 inhibition attenuated hepatic steatosis, improved hepatic insulin sensitivity, reduced hepatic glucose production, increased capacity for β-oxidation and ketogenesis, and decreased the capacity for lipogenesis. These results were attributed to altered enzymatic capacities and a reduction in TCA anaplerosis that limited the availability of oxaloacetate for the TCA cycle, which promoted ketogenesis. The current study reports that increasing hepatic PDC activity by inhibition of PDK2 ameliorates hepatic steatosis and insulin sensitivity by regulating TCA cycle anaplerosis and ketogenesis. The findings suggest PDK2 is a potential therapeutic target for nonalcoholic fatty liver disease.

Effects of collection time on flow of chromium and dry matter and on basal ileal endogenous losses of amino acids in growing pigs

The objectives of this experiment were to examine the diurnal patterns of chromium and DM flow at the distal ileum of pigs and to determine the effect of collection time on basal ileal endogenous losses (BEL) of CP and AA. Eight barrows with an initial BW of 34.6kg (SD = 2.1) were individually fitted with a T-cannula in the distal ileum and randomly allotted to a replicated 4× 4 Latin square design with 4 diets and 4 periods in each square. Three diets contained either corn, soybean meal, or distillers dried grains with solubles as the sole source of CP and AA. An N-free diet was also prepared. All diets contained 0.5% chromic oxide as an indigestible marker. Equal meals were provided at 0800 and 2000 h. Ileal digesta samples were collected in 2-h intervals from 0800 to 2000 h during the last 3 d of each 7-d period. The concentration of Cr in ileal digesta samples collected in each of the six 2-h periods exhibited a quadratic effect ( < 0.01) that increased and then decreased in pigs fed the CP containing diets. However, the concentration of Cr in ileal digesta collected in each of the six 2-h periods from pigs fed the N-free diet increased (linear, < 0.01). These differences were possibly related to differences in DM flow, because DM flow to the distal ileum had a pattern that was opposite of that observed for the concentration of Cr in the ileal digesta samples. The BEL of all indispensable AA and the sum of indispensable AA from pigs fed the N-free diet decreased (linear, < 0.05) in each of the six 2-h periods, with the exception that the BEL of Arg increased and then decreased (quadratic, < 0.05). The BEL of Asp, Cys, Glu, Ser, and Tyr also decreased (linear, < 0.05) during each of the six 2-h periods, whereas the BEL of Pro and the sum of dispensable AA increased and then decreased (quadratic, < 0.05) over the 12 h. Collection time did not affect BEL of CP. No differences were observed in the concentration of Cr, flow of DM, or basal endogenous loss of all AA if ileal digesta samples were collected over 6-, 8-, or 10-h periods, compared with collection over a 12-h period. In conclusion, diurnal variation of Cr concentration, DM flow, and the BEL of all AA were observed, but 4 to 6 h of ileal sample collection starting 4 or 6 h after feeding may provide representative samples that allow for calculation of accurate values for CP and AA digestibility.

Different Coefficients and Exponents for Metabolic Body Weight in a Model to Estimate Individual Feed Intake for Growing-finishing Pigs

Estimation of feed intake (FI) for individual animals within a pen is needed in situations where more than one animal share a feeder during feeding trials. A partitioning method (PM) was previously published as a model to estimate the individual FI (IFI). Briefly, the IFI of a pig within the pen was calculated by partitioning IFI into IFI for maintenance (IFI_m) and IFI for growth. In the PM, IFI_m is determined based on the metabolic body weight (BW), which is calculated using the coefficient of 106 and exponent of 0.75. Two simulation studies were conducted to test the hypothesis that the use of different coefficients and exponents for metabolic BW to calculate IFI_m improves the accuracy of the estimates of IFI for pigs, and that PM is applied to pigs fed in group-housing systems. The accuracy of prediction represented by difference between actual and estimated IFI was compared using PM, ratio (RM), or averaging method (AM). In simulation studies 1 and 2, the PM estimated IFI better than the AM and RM during most of the periods (p<0.05). The use of 0.60 as the exponent and the coefficient of 197 to calculate metabolic BW did not improve the accuracy of the IFI estimates in both simulation studies 1 and 2. The results imply that the use of 197 kcal×kg BW^0.60 as metabolizable energy for maintenance in PM does not improve the accuracy of IFI estimations compared with the use of 106 kcal×kg BW^0.75 and that the PM estimates the IFI of pigs with greater accuracy compared with the averaging or ratio methods in group-housing systems.

In vitro Solubility of Copper(II) Sulfate and Dicopper Chloride Trihydroxide for Pigs

This study was conducted to determine the solubility of copper (Cu) in two sources of copper(II) sulfate (CuSO₄) including monohydrate and pentahydrate and three sources of dicopper chloride trihydroxide (dCCTH) including α-form (dCCTH-α), β-form (dCCTH-β), and a mixture of α- and β-form (dCCTH-αβ) at different pH and a 3-step in vitro digestion assay for pigs. In Exp. 1, Cu sources were incubated in water-based buffers at pH 2.0, 3.0, 4.8, and 6.8 for 4 h using a shaking incubator at 39°C. The CuSO₄ sources were completely dissolved within 15 min except at pH 6.8. The solubility of Cu in dCCTH-α was greater (p<0.05) than dCCTH-β but was not different from dCCTH-αβ during 3-h incubation at pH 2.0 and during 2-h incubation at pH 3.0. At pH 4.8, there were no significant differences in solubility of Cu in dCCTH sources. Copper in dCCTH sources were non-soluble at pH 6.8. In Exp. 2, the solubility of Cu was determined during the 3-step in vitro digestion assay for pigs. All sources of Cu were completely dissolved in step 1 which simulated digestion in the stomach. In Exp. 3, the solubility of Cu in experimental diets including a control diet and diets containing 250 mg/kg of additional Cu from five Cu sources was determined during the in vitro digestion assay. The solubility of Cu in diets containing additional Cu sources were greater (p<0.05) than the control diet in step 1. In conclusion, the solubility of Cu was influenced by pH of digesta but was not different among sources based on the in vitro digestion assay.

Resistance to hypertension and high Cl- excretion in humans with SLC26A4 mutations

Pendrin is a membrane transporter encoded by solute carrier family26A4 (SLC26A4). Mutations in this gene are known to cause hearing loss, and recent data from animal studies indicate a link between pendrin expression and hypertension; although, this association in humans is unclear. To clarify this issue, we investigated the influence of pendrin on blood pressure by analyzing demographic and biochemical data - including blood pressure and urinary electrolyte excretion - in patients with bi-allelic SLC26A4 mutations. Systolic and diastolic blood pressure and the left ventricular hypertrophy index were lower in subjects with pendrin mutations than in controls. In addition, fractional excretion of Na⁺ and Cl^- was increased and serum renin, angiotensin I and II levels were higher in subjects with pendrin mutations as compared to controls. Thus, patients with impaired pendrin function are likely to be resistant to high blood pressure due to enhanced urinary Na⁺ /Cl^- excretion. These results suggest that pendrin may regulate blood pressure through increased urinary salt excretion.

H. pylori infection promotes intestinal inflammation and colitis-associated colon cancer in mice with a lineage-restricted deletion of the Smad4 gene in T cells

Recent data suggest a protective effect of Helicobacter pylori (H. pylori) infection in inflammatory bowel disease (IBD), but the mechanisms mediating this protective effect are poorly understood. We previously reported that selective deletion in T cells of the TGF-β signaling intermediate in mice, Smad4 (Smad4TKO mice) leads to spontaneous gastrointestinal inflammation which progresses to mucosal epithelia cancers. Thus we infected Smad4TKO mice with H. pylori SS1 and PMSS1. Smad4TKO mice developed thickened intestinal mucosa, epithelial hyperplasia, crypt abscesses, and abundant inflammatory cell infiltrates between 2 and 3 months post infection. Some mice also developed colonic adenocarcinoma while wild type (WT) infected mice exhibited no gross or histologic signs of colitis. Smad4TKO mice infected with H. pylori had a increase in the number of mucosal effector CD4+ T cells producing IFN-g and IL-17 and a decrease in the mucosal Foxp3+CD4+ T cells (Tregs) in vivo, compared to WT mice infected with H. pylori. We also observed enhanced epithelia expressing PD-L1 in colon of Smad4TKO mice with H. pylori infection. The colon epithelia of Smad4TKO mice with H. pylori infection exhibited an oncogenic signature with an increase in the expression of iNOS and p-STAT1. Mutations in Smad4 are found in large percentage of human Juvenile Polyposis Syndrome (JPS) and Hereditary Hemorrhagic Telangiectasia (HTT) patients who are at risk of developing both adolescent and adult colon cancer. Our results raise the intriguing possibility that H. pylori infection could be a co-factor in the development of colon cancer by JPS/HTT patients.

Myeloid-derived suppressor cells: The green light for myeloma immune escape

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous, immature myeloid cell population with the ability to suppress innate and adaptive immune responses that promote tumor growth. MDSCs are increased in patients with multiple myeloma (MM) and have bidirectional interaction with tumors within the MM microenvironment. MM-MDSCs promote MM tumor growth and induce immune suppression; conversely, MM cells induce MDSC development and survival. Although the role of MDSCs in infections, inflammatory diseases and solid tumors has been extensively characterized, their tumor-promoting and immune-suppressive role in MM and the MM microenvironment is only beginning to emerge. The presence and activation of MDSCs in MM patients has been well documented; however, the direct actions and functional consequences of MDSCs on cancer cells is poorly defined. Immunosuppressive MDSCs play an important role in tumor progression primarily because of their capability to promote immune-escape, angiogenesis, drug resistance and metastasis. However, their role in the bone marrow (BM), the primary MM site, is poorly understood. MM remains an incurable malignancy, and it is likely that the BM microenvironment protects MM against chemotherapy agents and the host immune system. A growing body of evidence suggests that host immune cells with a suppressive phenotype contribute to a myeloma immunosuppressive network. Among the known suppressor cells, MDSCs and T regulatory cells (Tregs) have been found to be significantly increased in myeloma patients and their levels correlate with disease stage and clinical outcome. Furthermore, it has been shown that MDSC can mediate suppression of myeloma-specific T-cell responses through the induction of T-cell anergy and Treg development in the MM microenvironment. Here, we review clinical correlations and the preclinical proof-of-principle data on the role of MDSCs in myeloma immunotolerance and highlight the mechanistically relevant MDSC-targeted compounds and their potential utility in a new approach for anti-myeloma therapy.

Effects of intraoperative protective lung ventilation on postoperative pulmonary complications in patients with laparoscopic surgery: prospective, randomized and controlled trial

BACKGROUND

Respiratory functions are usually impaired during pneumoperitoneum for laparoscopic surgery. This randomized, controlled and single-blinded study was performed to evaluate whether intraoperative protective lung ventilation influences postoperative pulmonary complications after laparoscopic hepatobiliary surgery.

METHODS

Sixty-two patients were randomized to receive either conventional ventilation with alveolar recruitment maneuver (tidal volume of 10 ml/kg with inspiratory pressure of 40 cmH2O for 30 s after the end of pneumoperitoneum, group R), or protective lung ventilation (low tidal volume of 6 ml/kg with positive end-expiratory pressure [PEEP] of 5 cmH2O, group P). Induction and maintenance of anesthesia were done with balanced anesthesia. Respiratory complications such as atelectasis, pneumonia or desaturation were observed postoperatively. The length of hospital stay, arterial blood gas analysis, peak inspiratory pressure and hemodynamic variables were also recorded. Results are presented as mean ± SD or number of patients (%).

RESULTS

Postoperative pulmonary complications (P = 0.023) and desaturation below 90 % (P = 0.016) occurred less frequently in group P than in group R. Eight patients of group R and 3 patients of group P showed atelectasis. Pneumonia was diagnosed in 1 patient of group R. No differences were observed in the length of hospital stay, arterial blood gas analysis (pH, PaO2, PaCO2 and PAO2) and hemodynamic variables except PAO2, AaDO2 and peak inspiratory pressure between the two groups.

CONCLUSION

Protective lung ventilation (low tidal volume with PEEP) during pneumoperitoneum was associated with less incidences of pulmonary complications than conventional ventilation with alveolar recruitment maneuver after laparoscopic hepatobiliary surgery.

Autocrine Action of Thrombospondin-2 Determines the Chondrogenic Differentiation Potential and Suppresses Hypertrophic Maturation of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells

Previous studies have shown that mesenchymal stem cell (MSC)-based therapies have varying efficacies for the treatment of various diseases, including cartilage defects. In this study, we demonstrated that the chondrogenic differentiation potential of human umbilical cord blood-derived MSCs (hUCB-MSCs) obtained from different individual donors varies, and we investigated the molecular basis for this variation. Microarray gene expression analysis identified thrombospondin-2 (TSP2) as a candidate gene underlying the interindividual variation in the chondrogenic differentiation potential of hUCB-MSCs. To assess the association between TSP-2 and the differentiation potential, we evaluated chondrogenic differentiation of hUCB-MSCs treated with TSP2 siRNA. In addition, we studied the effect of supplementing exogenous recombinant TSP-2 on TSP2 siRNA-treated hUCB-MSCs. We found that TSP-2 autocrinally promoted chondrogenic differentiation of hUCB-MSCs via the Notch signaling pathway, which was confirmed in MSCs from other sources such as bone marrow and adipose tissue. Interestingly, we observed that TSP-2 attenuated hypertrophy, which inevitably occurs during chondrogenic differentiation of hUCB-MSCs. Our findings indicated that the variable chondrogenic differentiation potential of MSCs obtained from different donors is influenced by the TSP-2 level in the differentiating cells. Thus, the TSP-2 level can be used as a marker to select MSCs with superior chondrogenic differentiation potential for use in cartilage regeneration therapy.

Hepatic Stellate Cells Inhibit T Cells through Active TGF-β1 from a Cell Surface-Bound Latent TGF-β1/GARP Complex

Hepatic stellate cells (HSCs) inhibit T cells, a process that could help the liver to maintain its immunoprivileged status. HSCs secrete latent TGF-β1, but the detailed mechanisms by which latent TGF-β1 is activated and whether it plays any role in HSC-mediated T cell suppression remain unclear. Glycoprotein A repetitions predominant (GARP) is a surface marker of activated regulatory T cells. GARP binds latent TGF-β1 for its activation, which is critical for regulatory T cells to suppress effector T cells; however, it is still unclear whether GARP is present on HSCs and whether it has any impact on HSC function. In this study, we found that TGF-β1(+/-) HSCs, which produce reduced levels of TGF-β1, showed decreased potency in inhibiting T cells. We also found that pharmaceutical or genetic inhibition of the TGF-β1 signaling pathway reduced the T cell-inhibiting activity of HSCs. Additionally, using isolated primary HSCs, we demonstrated that GARP was constitutively expressed on HSCs. Blocking GARP function or knocking down GARP expression significantly impaired the potency of HSCs to suppress the proliferation of and IFN-γ production from activated T cells, suggesting that GARP is important for HSCs to inhibit T cells. These results demonstrate the unexpected presence of GARP on HSCs and its significance in regard to the ability of HSCs to activate latent TGF-β1 and thereby inhibit T cells. Our study reveals a new mechanism for HSC-mediated immune regulation and potentially for other conditions, such as liver fibrosis, that involve HSC-secreted TGF-β1.

Abstract LB-266: Suppression of colitis-associated colon carcinogenesis by the natural triterpenoid celastrol

Celastrol is a natural triterpenoid isolated from the medicinal herb Triptyrgium wilfordii, commonly known as the Thunder of God vine. Celastrol has been shown to have a broad range of anti-inflammatory and anti-cancer activities. Here we investigated whether celastrol administered as a dietary supplement can inhibit both colitis and colitis-associated colon cancer (CAC) in either genetic or chemically-induced CAC mouse models. As a genetic and spontaneous, inflammatory-driven intestinal neoplasia model, we generated a Smad4TKO / p27Kip1-/- (DKO) mouse in which a germ line p27Kip1 gene deletion (p27Kip1-/-) was combined with the T cell-restricted deletion of the Smad4 gene (Smad4TKO). All DKO mice developed spontaneous gastrointestinal inflammation and colon carcinoma by 3 months of age. Administration of celastrol as a dietary supplement (2 mg/day) to DKO mice increased survival and suppressed intestinal epithelial neoplasia by decreasing production of inflammatory mediators, including TNF-alpha, IL-6, IL-1beta and iNOS. We investigated the chemopreventive activity of celastrol in the chemically induced CAC mouse model using dextran sulfate sodium (DSS)/azoxymethane (AOM). Mice (C57/BL6, ages 6-8 weeks) received intraperitoneal injections with 10 mg/kg AOM, followed by exposure to 2% DSS in drinking water for 7 days. We repeated 3 cycles of 2% DSS, with 10 days of normal drinking water provided between cycles. Mice were either maintained on control diet or given celastrol (2 mg/day) diet beginning with first administration of DSS and continuing until termination of the experiment. Mice receiving celastrol diet showed less loss in body weight compared with the control diet group and marked protection from AOM/DSS-induced colon cancer. The incidence and number of colonic tumors in mice in the celastrol diet group were also significantly lower than those in control diet group. These results were accompanied by decreased expression of iNOS and lower production of pro-inflammatory cytokines. Our data demonstrate the protective effects of celastrol in the chemoprevention of CAC, was and this effect correlated with a dampening of iNOS expression and with a decrease of inflammatory cytokine production. These results highlight the potential of celastrol as an effective agent for the chemoprevention of CAC in humans.

Citation Format: Sung Hee Choi, Emily Baker, Byung-Gyu Kim, Gregory Tochtrop, John J. Letterio. Suppression of colitis-associated colon carcinogenesis by the natural triterpenoid celastrol. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-266. doi:10.1158/1538-7445.AM2015-LB-266

Cyclin-dependent kinase 5 represses Foxp3 gene expression and Treg development through specific phosphorylation of Stat3 at Serine 727

Cyclin-dependent kinase 5 (Cdk5) is known as a unique member of the cyclin-dependent family of serine/threonine kinases. Previously, we demonstrated Cdk5 to be an important regulator of T cell function and that disruption of Cdk5 expression ameliorates T cell mediated neuroinflammation. Here, we show a novel role of Cdk5 in the regulation of Foxp3 expression in murine CD4(+) T cells. Our data indicate that disruption of Cdk5 activity in T cells abrogates the IL-6 suppression of Foxp3 expression. This effect is achieved through Cdk5 phosphorylation of the signal transducer and activator of transcription 3 (Stat3) specifically at Serine 727 in T cells, and we show this post-translational modification is required for proper Stat3 DNA binding to the Foxp3 gene on the enhancer II region. Taken together, our data point to an essential role for Cdk5 in the differentiation of T cells as it regulates Foxp3 gene expression through phosphorylation of Stat3.

Interaction between hypertension and cerebral hypoperfusion in the development of cognitive dysfunction and white matter pathology in rats

Hypertension is the most significant modifiable risk factor for vascular cognitive impairment. However, influence of hypertension on the development of ischemic white matter injury and cognitive dysfunction is not fully understood. We compared cognitive functions and neuropathological outcomes of chronic cerebral hypoperfusion induced by bilateral common carotid artery occlusion (BCCAO) between normotensive rats (NRs) and spontaneously hypertensive rats (SHRs). SHRs developed earlier and more severe deficits in spatial memory performance than NRs following BCCAO. Although no significant changes in the gross structure of myelinated white matter or oligodendrocyte number were noted, BCCAO resulted in subtle myelin degeneration and paranodal structural alterations at the nodes of Ranvier, regardless of hypertension. Disruption of the blood-brain barrier (BBB) was predominantly observed in the white matter of SHRs following BCCAO, implying a role of hypertension in BBB dysfunction in chronic cerebral hypoperfusion. In chronic cerebral ischemia, long-standing hypertension may aggravate impairment of BBB integrity, and the leaky BBB may in turn exacerbate dysfunction in the white matter leading to worsening of spatial cognitive performance.

Effects of Supplemental Beta-mannanase on Digestible Energy and Metabolizable Energy Contents of Copra Expellers and Palm Kernel Expellers Fed to Pigs

The purpose of this study was to determine the effect of β-mannanase supplementation on digestible energy (DE) and metabolizable energy (ME) contents of copra expellers (CE) and palm kernel expellers (PKE) fed to pigs. Six barrows with an initial body weight of 38.0 kg (standard deviation = 1.5) were randomly allotted to a 6×6 Latin square design with 6 dietary treatments and 6 periods. Six experimental diets were prepared in a 3×2 factorial treatment arrangement with 3 diets of a corn-soybean meal-based diet, a CE 30% diet, and a PKE 30% diet and with 2 concentrations of supplemental β-mannanase at 0 or 2,400 U/kg. All diets had the same proportion of corn:soybean meal ratio at 2.88:1. The marker-to-marker procedure was used for fecal and urine collection with 4-d adaptation and 5-d collection periods. No interactive effects were observed between diet and β-mannanase on energy digestibility and DE and ME contents of experimental diets. However, diets containing CE or PKE had less (p<0.05) DE and ME contents compared with the corn-soybean meal-based diet. The DE and ME contents in CE and PKE were not affected by supplemental β-mannanase. Taken together, we failed to find the effect of β-mannanase supplementation on energy utilization in CE and PKE fed to pigs.