Changes in the clinical course and prognosis of ulcerative colitis in Chinese populations: a retrospective cohort study

Background/Aims

Data on the natural course of Chinese patients with ulcerative colitis (UC) was lacking. This study aimed to evaluate the natural history and prognosis of patients with UC in the past 15 years in China.

Methods

This cohort study included patients with UC in a tertiary hospital in southern China from 2007 to 2021 (cohort I: 2007-2011, cohort II: 2012-2016, cohort III: 2017-2021). Patients' clinical characteristics and natural history were analyzed retrospectively.

Results

Of 1,139 included patients, 683 patients presented with proctitis or left-sided colitis at diagnosis and 38.5% of them (263/683) developed proximal disease extension. Fifty-eight percent of patients experienced relapse, chronic continuous and intermittent active course. Five patients (0.4%) developed colorectal tumors/dysplasia. The overall surgery rate was 8.6%, and the rates were 14.2%, 7.8%, and 8.0% in the 3 cohorts, respectively (P= 0.059). Average time from diagnosis to surgery decreased from cohorts I to III (144 months vs. 36 months, P< 0.001), so did the use of glucocorticoids (58.2% vs. 43.5%, P< 0.001) and immunosuppressants (14.1% vs. 13.4%, P= 0.016), and days of hospitalization (13 days vs. 9 days, P< 0.001). Biologics were used more frequently during the first year (0.8%, 2.1%, and 13.7% for cohorts I to III, respectively; P< 0.001). The rate of mucosal healing increased over time.

Conclusions

In Chinese UC patients, one-third of patients experienced proximal disease extension. The rates of malignancy and mortality were low. More biologics were used, while use of immunosuppressants and glucocorticoids were reduced over time. Early biologics use seemed to promote mucosal healing, but the rate of colectomy has not dramatically decreased.

Amino acid-based enteral nutrition is effective for pediatric Crohn's disease: a multicenter prospective study

Background

Exclusive enteral nutrition (EEN) therapy effectively induces remission in pediatric Crohn's disease (CD). However, this may depend on the type of enteral formula used. Moreover, data on the efficacy of amino acid-based EEN are limited. Thus, we aimed to prospectively evaluate the efficacy of amino acid-based formulas for EEN in pediatric patients with active CD.

Methods

Patients with active CD aged between 6 and 17 years were recruited into this prospective study from four hospitals in China between March 2019 and December 2021. Patients received EEN for 8 weeks. Inflammatory and nutrition-associated indices were evaluated at 0, 4, and 8 weeks after treatment. Paired t-tests and Wilcoxon signed-rank tests were used to compare continuous and categorical variables before and after intervention, respectively.

Results

Twenty-four patients were included in the analysis. After an 8-week intervention period, the CD activity index significantly decreased (26.3 ± 12.2 vs 7.1 ± 8.3, P < 0.001). Most patients (66.7%) achieved complete clinical remission. Among the 22 patients who had ulcers and erosions diagnosed endoscopically at baseline, 10 (45.5%) achieved complete mucosal healing. The degree of thickening of the intestinal wall was significantly reduced after EEN intervention, with a transmural healing rate of 42.9%. Furthermore, the serum inflammatory markers decreased and there was a significant improvement in the nutrition-related indices (P < 0.05). There were no severe adverse effects.

Conclusions

Amino acid-based EEN is effective and safe for treating pediatric-onset CD. Studies with larger sample sizes and mechanistic and follow-up studies are required to further validate these findings.

Exclusive Enteral Nutrition Orchestrates Immunological Balances as Early as Week 4 in Adult Patients of Crohn's Disease: A Pilot, Open-Lable Study

BACKGROUND AND AIMS

The efficacy and underlying mechanisms of exclusive enteral nutrition (EEN) in adult patients with Crohn's disease (CD) remain controversial. This study aimed to evaluate the role of EEN in adult patients with CD and to explore the mechanisms from the perspective of immunoregulation.

METHODS

This is a prospective, open-label pilot study. Active patients with CD were enrolled and prescribed an amino-acid-rich elemental diet for 12 weeks. Dynamic changes in immune cells, including neutrophils, monocytes, T cells and B cells, were detected by flow cytometry. Plasma cytokines were evaluated by ELISA.

RESULTS

Twenty adult patients with CD were enrolled. Among them, 1 discontinued treatment due to poor compliance, and 19 patients were included for final analysis. Clinical remission was achieved in 47.37% (9/19), 63.16% (12/19), and 73.68% (14/19) patients at weeks 4, 8, and 12, respectively. Endoscopic remission and transmural healing were achieved in 52.63% (10/19) and 15.79% (3/19) patients at week 12. Notably, there was no significant difference in clinical remission between week 4 and week 8 (p = 0.33) or week 12 (p = 0.09). Furthermore, we observed a rapid reconstitution of immunologic homeostasis as early as week 4. At week 4, both the frequency and activation of neutrophils and monocytes were decreased after EEN therapy. Significant decreases in Th17 cells and naïve B cells, increases in memory B cells, and regulatory B cells were also detected. These changes remained stable at weeks 8 and 12.

CONCLUSIONS

EEN with an amino-acid-rich elemental diet orchestrated immunological balances and induces clinical remission in adult CD patients as early as week 4, suggesting a 4-week EEN therapy may be feasible and practicable in clinical practice.

A frameshift variant in the SIRPB1 gene confers susceptibility to Crohn's disease in a Chinese population

Background: Crohn's disease (CD), a chronic gastrointestinal inflammatory disease, is increasing in China. With a focus on Han Chinese families with CD, the aim of this study was to find genetic variations that increase CD susceptibility by genome sequencing, genetic association, expression, and functional research. Materials and methods: We performed family-based genome sequencing (WGS) analysis on 24 patients with CD from 12 families and then filtered shared potential causal variants by incorporating association results from meta-analyses of CD GWAS and immunology genes and in silico variant effect prediction algorithms. Replication analyses were performed in an independent cohort including 381 patients with CD and 381 control subjects. Results: There were 92 genetic variants significantly associated with CD in Chinese individuals. Among them, 61 candidate loci were validated in replication analyses. As a result, patients carrying a rare frameshift variant (c.1143_1144insG; p. Leu381_Leu382fs) in gene SIRPB1 had significantly higher risk to develop CD (p = 0.03, OR 4.59, 95% CI 0.98-21.36, 81.82% vs. 49.53%). The frameshift variation induced tyrosine phosphorylation of Syk, Akt, and Jak2, elevated the expression of SIRPB1 at the mRNA and protein levels, activated DAP12, and controlled the activation of NF-κB in macrophages. Additionally, it promoted the synthesis of the pro-inflammatory cytokines IL-1, TNF-, and IL-6. Conclusion: Our results suggest that the rare gain-of-function frameshift variant in SIRPB1 is associated in Han Chinese patients with CD. The functional mechanism of SIRPB1 and its downstream inflammatory pathways was preliminarily explored in CD.

DNA-Thioguanine Nucleotides as a Marker for Thiopurine Induced Late Leukopenia after Dose Optimizing by NUDT15 C415T in Chinese Patients with IBD

Thiopurine dose optimization by thiopurine-S-methyltransferase (TPMT) or nudix hydrolase-15 (NUDT15) significantly reduced early leucopenia in Asia. However, it fails to avoid the late incidence (> 2 months). Although laboratory monitoring of 6-thioguanine nucleotides (6TGN) to optimize thiopurine dose was suggested in White patients the exact association between leucopenia and 6TGN was controversial in Asian patients. In the present study, we aimed to explore whether DNA-thioguanine nucleotides (DNA-TGs) in leukocytes, compared with 6TGN in erythrocytes, can be a better biomarker for late leucopenia. This was a prospective, observational study. Patients with inflammatory bowel disease (IBD) prescribed thiopurine from February 2019 to December 2019 were recruited. Thiopurine dose was optimized by NUDT15 C415T (rs116855232). DNA-TG and 6TGN levels were determined at the time of late leucopenia or 2 months after the stable dose was obtained. A total of 308 patients were included. Thiopurine induced late leucopenia (white blood cells < 3.5 × 10⁹ /L) were observed in 43 patients (14.0%), who had significantly higher DNA-TG concentration than those without leucopenia (P = 4.1 × 10^-9 , 423.3 (~ 342.2 to 565.7) vs. 270.5 (~ 188.1 to 394.3) fmol/μg DNA). No difference in 6TGN concentrations between leucopenia and non-leucopenia was found. With a DNA-TG threshold of 340.1 fmol/μg DNA, 83.7% of leucopenia cases could be identified. Multivariate analysis showed that DNA-TG was an independent risk factor for late leucopenia. Quantification of DNA-TG, rather than 6TGN, can be applied to gauge thiopurine therapy after NUDT15 screening in Chinese patients with IBD.

Lipidomics reveals significant alterations associated with exclusive enteral nutrition treatment in adult patients with active Crohn’s disease

Background

Crohn’s disease (CD), a type of inflammatory bowel disease, is a chronic idiopathic disorder of the gastrointestinal tract with an increasing global incidence. Exclusive enteral nutrition (EEN) is a diet therapy that is effective in the management of active CD with unknown etiology. Lipid metabolism plays an important role in CD and may be associated with EEN treatment. This study compared the plasma lipid profiles before and after EEN in adults with active CD to those of healthy controls (HCs).

Methods

Eleven adult patients with active CD who received enteral nutrition formula treatment for 12 weeks were included, along with 17 HCs. The profiles of 869 plasma lipid species were measured, and inflammatory and nutrition-associated indices were evaluated in the patients.

Results

Nine patients achieved clinical remission following 12 weeks of EEN treatment, and four achieved mucosal healing. Before EEN, 80 lipid species and 17 lipid classes were significantly different between patients with CD and HCs. After EEN treatment, 103 lipid species and 12 lipid classes were significantly different between patients with CD and HCs. Significant changes in 7 lipid classes and 38 lipid species were observed between the pre- vs. post-treatment CD patients. The levels of simplified glucosylceramide series, monogalactosyldiacylglycerol, phosphatidylinositol, phosphatidylserine, and phosphatidylcholine increased, while those of phosphatidylglycerol and phosphatidylinositol diphosphate decreased significantly after EEN. These lipid classes and species were associated with the inflammatory and nutritional indices. Pathway analysis suggested the metabolism of arachidonic acid, glycerophospholipids, linoleate, and phosphatidylinositol phosphate was related to the EEN mechanism.

Conclusions

EEN induces alterations in multiple lipid classes and species, leading to clinical improvements. Lipid metabolism may be involved in the EEN anti-inflammatory effect.

CircFGGY Inhibits Cell Growth, Invasion and Epithelial-Mesenchymal Transition of Hepatocellular Carcinoma via Regulating the miR-545-3p/Smad7 Axis

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. Circular RNAs (circRNAs) play critical roles in the progression of HCC. However, the role of the newly identified circFGGY (hsa_circ_0006633) in the development and progression of HCC has not been explored. In this study, we found that circFGGY was significantly downregulated in tumor compared with that in adjacent normal liver tissues of patients with HCC. HCC patients with low circFGGY expression had poor overall survival after hepatectomy. Moreover, it was found that circFGGY could inhibit the proliferation, invasion and epithelial-mesenchymal transition of HCC both in vivo and in vitro. Mechanistically, circFGGY promoted the expression of Smad7, a well-known suppressor of the transforming growth factor-β signaling pathway. In addition, miR-545-3p, a tumor promoter targeting both circFGGY and Smad7, suppressed the upregulation of Smad7 caused by circFGGY overexpression. Collectively, our data revealed that circFGGY inhibits the proliferation and invasion of HCC cells by sponging miR-545-3p and promote the expression of Smad7, indicating that circFGGY functions as a tumor suppressor and could be a prognostic biomarker for HCC.

Systematic review with meta-analysis: loss of response and requirement of ustekinumab dose escalation in inflammatory bowel diseases

BACKGROUND

Ustekinumab is effective in treating Crohn's disease (CD) and ulcerative colitis (UC). However, the loss of response (LOR) to ustekinumab and the efficacy of dose escalation have not been systematically explored.

METHODS

Databases were searched for eligible studies from inception through July 2021. Summary estimates were pooled, and subgroup analyses were performed to explore heterogeneity.

RESULTS

We included 14 studies (CD: 13; UC: 1). In CD patients, the annual risk of LOR to ustekinumab and dose escalation among primary responders was 21% (95% confidence interval [CI] 12-31%, 1530 person-years, n = 9) per person-year and 25% (95% CI 12-32%, 657 person-years, n = 5) per person-year respectively. Clinical response was regained in 58% (95% CI 49-67%, 279 patients, n = 8) of secondary non-responders after dose escalation (interval reduction or intravenous reinduction). In UC patients, no studies provided data on LOR, but only one study showed that 35% (100/284) of patients underwent dose escalation (or sham dose adjustment), leading to an annual risk of dose escalation of 18% per person-year. After dose escalation, 58% (14/24) of the patients regained symptomatic remission.

CONCLUSIONS

Primary responders with CD experienced LOR to ustekinumab at a risk of 21% per person-year and required dose escalation at a risk of 25% per person-year. Fifty-eight per cent of secondary non-responders with CD may benefit from dose escalation. LOR has not been well characterized in patients with UC.

Parathyroid hormone-related protein prevents high-fat-diet-induced obesity, hepatic steatosis and insulin resistance in mice

Obesity, closely related to systematic metabolic disorders, has become a major public health problem in recent decades. Here, we aimed to study the function of Parathyroid hormone-related protein (PTHrP) on high fat diet (HFD) induced murine obesity. Male C57BL/6J mice were transduced with adeno-associated virus vector encoding PTHrP (AAV-PTHrP) or adeno-associated virus control vector (AAV-Vehicle), following with HFD for 8 weeks. In addition, mice without transduction were fed on normal diet or HFD, respectively. Histological, metabolic and biochemical changes were detected. At the endpoint of experiment, body weight of mice treated with AAV-PTHrP did not increase as much as mice with AAV-Vehicle, but similar as mice with normal diet. Food efficiency ratio and weight of interscapular brown adipose tissue and epididymal white adipose tissue in mice overexpressed PTHrP were also lower than mice transducted with AAV-Vehicle. Besides, administration of AAV-PTHrP inhibited HFD-induced adipocyte hypertrophy. Protein level of PKA signaling pathway and thermogenic gene in adipose tissue exhibited a significant raise in HFD + AAV-PTHrP group, whereas transcription of inflammatory gene were decreased. Additionally, PTHrP overexpression ameliorated HFD-induced dyslipidemia, hepatic steatosis and insulin sensitivity. In HFD-induced murine obesity model, PTHrP is crucial to maintain metabolic homeostasis. PTHrP drives white adipose tissue browning and inhibits whitening of brown adipose tissue. Most importantly, PTHrP prevented HFD-induced obesity, hepatic steatosis and insulin resistance.

Neutrophils Deficient in Innate Suppressor IRAK-M Enhances Anti-tumor Immune Responses

Tumor-associated immune-suppressive neutrophils are prevalent in various cancers, including colorectal cancer. However, mechanisms of immune-suppressive neutrophils are not well understood. We report that a key innate suppressor, IRAK-M (interleukin-1 receptor-associated kinase M), is critically involved in the establishment of immune-suppressive neutrophils. In contrast to the wild-type (WT) neutrophils exhibiting immune-suppressive signatures of CD11b^highPD-L1^highCD80^low, IRAK-M-deficient neutrophils are rewired with reduced levels of inhibitory molecules PD-L1 and CD11b, as well as enhanced expression of stimulatory molecules CD80 and CD40. The reprogramming of IRAK-M-deficient neutrophils is mediated by reduced activation of STAT1/3 and enhanced activation of STAT5. As a consequence, IRAK-M-deficient neutrophils demonstrate enhanced capability to promote, instead of suppress, the proliferation and activation of effector T cells both in vitro and in vivo. Functionally, we observed that the transfusion of IRAK-M^-/- neutrophils can potently render an enhanced anti-tumor immune response in the murine inflammation-induced colorectal cancer model. Collectively, our study defines IRAK-M as an innate suppressor for neutrophil function and reveals IRAK-M as a promising target for rewiring neutrophils in anti-cancer immunotherapy.

Enhanced Neutrophil Immune Homeostasis Due to Deletion of PHLPP

Neutrophils are known to adopt dynamic and distinct functional phenotypes involved in the modulation of inflammation and immune homeostasis. However, inter-cellular signaling mechanisms that govern neutrophil polarization dynamics are not well understood. Employing a novel model of PHLPP deficient mice, we examined how neutrophils deficient in PHLPP may uniquely modulate immune defense and the host response during acute colitis. We found that PHLPP^-/- mice were protected from dextran sodium sulfate (DSS)-induced septic colitis characterized by minimal body weight-loss, alleviated colon tissue destruction and reduced clinical symptoms. PHLPP^-/- neutrophils have enhanced immune homeostasis as compared to WT neutrophils, reflected in enhanced migratory capacity toward chemoattractants, and reduced expression of inflammatory mediators due to elevated phosphorylation of AKT, STAT1, and ERK. Further, adoptive transfer of PHLPP deficient neutrophils to WT mice is sufficient to potently alleviate the severity of DSS-induced colitis. Our data reveal that PHLPP deficient neutrophils can be uniquely reprogrammed to a state conducive to host inflammation resolution. As a consequence, PHLPP^-/- neutrophils can effectively transfer immune homeostasis in mice subjected to acute colitis. Our findings hold significant and novel insights into the mechanisms by which neutrophils can be effectively reprogrammed into a homeostatic state conducive for treating acute injuries such as septic colitis.

Abstract 1515: Removal of innate suppressors facilitates tumor-immune surveillance

Although tumor immune environment is increasingly recognized to be highly important during the modulation of tumorigenesis and tumor regression, the role and regulation of innate leukocytes such as neutrophils during the modulation of tumor immune environment remain controversial and less defined. In this study, we tested the hypothesis that removal of innate signaling suppressors may boost the anti-tumor immune function of innate neutrophils in vitro and in vivo. To this regard, we examined two key innate signaling suppressors Tollip and IRAK-M and their roles in modulating neutrophil anti-tumor immune functions. We observed that selective deletion of Tollip enhanced tumor immune surveillance in the AOM-DSS chemically induced colon cancer model. Tollip deficiency released the neutrophil suppression on T cell proliferation and activation. The adoptive transfer of Tollip deficient neutrophils were sufficient to transfer enhanced tumor immune surveillance and reduce tumor burden. Likewise, the study of another innate suppressor IRAK-M revealed that IRAK-M expression was up-regulated in the human patients with colorectal cancer. We also demonstrated that IRAK-M deficient mice exhibited reduced tumor burden following AOM-DSS challenge. Together, our data reveal a novel anti-tumor immune-enhancement strategy through utilizing reprogrammed neutrophils with targeted removal of innate signaling suppressors.

Citation Format: Yao Zhang, Christina Lee, Na Diao, Liwu Li. Removal of innate suppressors facilitates tumor-immune surveillance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1515.

Modular Engineering of the Flavin Pathway in Escherichia coli for Improved Flavin Mononucleotide and Flavin Adenine Dinucleotide Production

In this work, modular engineering of Escherichia coli was peformed to improve flavin production and the conversion ratio of riboflavin (RF) to FMN/FAD. The RF operon and the bifunctional RF kinase/FAD synthetase were divided into two separate modules. The two modules were expressed at different levels to produce RF: ribF ratios ranging from 2:20 to 7:5. The best strain respectively produced 324.1 and 171.6 mg/L of FAD and FMN in shake flask fermentation, and the titers reached 1899.3 and 872.7 mg/L in a fed-batch process. Furthermore, error-prone PCR (epPCR) of the E. coli ribF gene was performed. The highest FMN production of the best mutant reached 586.1 mg/L in shake flask cultivation. Moreover, this mutant produced 1017.5 mg/L FMN with a greatly reduced proportion of FAD in fermenter culture. To the best of our knowledge, this is the highest production of FAD and FMN in a microbial fermentation process reported to date.

[The morphology and resilience change of upper airway in patients with OSAHS: A MSCT study]

Objective:To analyse the morphology and resilience of upper airway in patients with OSAHS using 128-slice MSCT. Method:CT imaging of the upper airway in 49 patients with OSAHS was acquired in two respiratory status (quiet respiration and Müller maneuver). The two-dimensional measurements of retropalatal and retroglossal regions, airway volume, and airway resilience were measured in patients with severe OSAHS and non-severe OSAHS. And the results were compared between those two groups. Result:① The following measurements during Müller maneuver were smaller than those during quiet respiration: the smallest cross section area of retropalatal and retroglossal region, the anteroposterior diameters(AP) and lateral diameters(L) of retropalatal region, L of retroglossal region, volume and average volume of upper airway and retropalatal area（P<0.01）.②The pharyngeal wall resilience of retropalata region was larger than those of retroglossal region in patients with severe OSAHS. The total resilience of retropalatal was larger than that of retroglossal region in patients with non-severe OSAHS. The pharyngeal wall resilience between severe and non-severe OSAHS had no significant difference. ③ L of retropalatal and retroglossal region, and average area of retropalatal region, were smaller in patients with severe OSAHS than those with non-severe OSAHS during Müller maneuver（P<0.05）.④ The cross-section of upper airway tend to be horizontal oval in retropalatal regions, and vertical oval in retroglossal regions. Conclusion:128-slice MSCT scan can achieve both positioning and quantitative analysis of the morphology and resilience changes of the upper airway in patients with OSAHS.

Autocrine parathyroid hormone-like hormone promotes intrahepatic cholangiocarcinoma cell proliferation via increased ERK/JNK-ATF2-cyclinD1 signaling

BACKGROUND AND AIMS

Intrahepatic cholangiocarcinoma (ICC) is an aggressive tumor with a high fatality rate. It was recently found that parathyroid hormone-like hormone (PTHLH) was frequently overexpressed in ICC compared with non-tumor tissue. This study aimed to elucidate the underlying mechanisms of PTHLH in ICC development.

METHODS

The CCK-8 assay, colony formation assays, flow cytometry and a xenograft model were used to examine the role of PTHLH in ICC cells proliferation. Immunohistochemistry (IHC) and western blot assays were used to detect target proteins. Luciferase reporter, chromatin immunoprecipitation (ChIP) and DNA pull-down assays were used to verify the transcription regulation of activating transcription factor-2 (ATF2).

RESULTS

PTHLH was significantly upregulated in ICC compared with adjacent and normal tissues. Upregulation of PTHLH indicated a poor pathological differentiation and intrahepatic metastasis. Functional study demonstrated that PTHLH silencing markedly suppressed ICC cells growth, while specific overexpression of PTHLH has the opposite effect. Mechanistically, secreted PTHLH could promote ICC cell growth by activating extracellular signal-related kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathways, and subsequently upregulated ATF2 and cyclinD1 expression. Further study found that the promoter activity of PTHLH were negatively regulated by ATF2, indicating that a negative feedback loop exists.

CONCLUSIONS

Our findings demonstrated that the ICC-secreted PTHLH plays a characteristic growth-promoting role through activating the canonical ERK/JNK-ATF2-cyclinD1 signaling pathways in ICC development. We identified a negative feedback loop formed by ATF2 and PTHLH. In this study, we explored the therapeutic implication for ICC patients.

Functional characterization of Irakm rΔ9–11 splice variant in mice

Ulcerative colitis (UC) and Crohn’s disease (CD) are two pathologies collectively referred to as Inflammatory Bowel Disease (IBD). While a definitive etiology is currently unknown, a complex interplay of environmental factors and genetic predispositions has been linked to IBD development. The Toll-like receptors (TLRs) are a family of pattern recognition receptors (PPRs) involved in the signaling pathways that regulate the inflammatory response, and as such, represent essential targets for therapeutic intervention of UC and CD. Interleukin receptor associated kinase M (IRAKM) is an important negative regulator of TLR signaling acting to attenuate an overzealous innate immune response. Metadata analysis of human patient samples afflicted with IBD revealed increased expression of IRAKM compared to both healthy controls and patients with inactive forms of IBD. Furthermore, our findings in murine studies have identified that commercially available Irakm−/− mice contain a spliced mRNA variant of the Irakm gene as a result of the knockout strategy; defined here to be IrakmrΔ9–11. We have found that the truncated IrakmrΔ9–11 protein robustly activates a NF-κB dependent luciferase reporter when overexpressed in mammalian cells. These results, together with data supporting the mechanistic role of this truncated protein, suggest an alternative explanation for the function of IRAK-M in TLR signaling and in modulating gastrointestinal immune homeostasis with potential therapeutic implications for IBD patients.

Deficiency in Toll-Interacting Protein (Tollip) Skews Inflamed yet Incompetent Innate Leukocytes in vivo during DSS-Induced Septic Colitis

The Toll-interacting protein (Tollip) is a critical regulator of Toll-like receptor-mediated innate immune responses. However, the role and mechanism of Tollip in the defense to bacterial infection remains poorly understood. In this study, we found that Tollip deficient mice were more susceptible to DSS induced acute colon injury. Tollip deficient mice displayed higher clinical scores with higher inflammatory cytokines in the blood. Further studies showed that Tollip deficient neutrophils had decreased migratory capacity, compromised bacterial killing activity, as well as reduced potential to generate neutrophil extra-cellular trap. On the other hand, Tollip deficient neutrophils had elevated levels of CCR5, responsible for their homing to sterile inflamed tissues. Together, our data reveal a novel mechanism in Tollip alteration that underlies the inflamed and incompetent polarization of neutrophils leading to severe outcomes of colitis.

Enhanced Mucosal Defense and Reduced Tumor Burden in Mice with the Compromised Negative Regulator IRAK-M

Aberrant inflammation is a hallmark of inflammatory bowel disease (IBD) and colorectal cancer. IRAK-M is a critical negative regulator of TLR signaling and overzealous inflammation. Here we utilize data from human studies and Irak-m^-/- mice to elucidate the role of IRAK-M in the modulation of gastrointestinal immune system homeostasis. In human patients, IRAK-M expression is up-regulated during IBD and colorectal cancer. Further functional studies in mice revealed that Irak-m^-/- animals are protected against colitis and colitis associated tumorigenesis. Mechanistically, our data revealed that the gastrointestinal immune system of Irak-m^-/- mice is highly efficient at eliminating microbial translocation following epithelial barrier damage. This attenuation of pathogenesis is associated with expanded areas of gastrointestinal associated lymphoid tissue (GALT), increased neutrophil migration, and enhanced T-cell recruitment. Further evaluation of Irak-m^-/- mice revealed a splice variant that robustly activates NF-κB signaling. Together, these data identify IRAK-M as a potential target for future therapeutic intervention.

Deficiency in Toll-interacting protein (Tollip) skews inflamed yet incompetent innate leukocytes in vivo during DSS-induced septic colitis

Functionally compromised neutrophils contribute to adverse clinical outcomes in patients with severe inflammation and injury such as colitis and sepsis. However, the ontogeny of dysfunctional neutrophil during septic colitis remain poorly understood. We report that the dysfunctional neutrophil may be derived by the suppression of Toll-interacting-protein (Tollip). We observed that Tollip deficient neutrophils had compromised migratory capacity toward bacterial product fMLF due to reduced activity of AKT and reduction of FPR2, reduced potential to generate bacterial-killing neutrophil extra-cellular trap (NET), and compromised bacterial killing activity. On the other hand, Tollip deficient neutrophils had elevated levels of CCR5, responsible for their homing to sterile inflamed tissues. The inflamed and incompetent neutrophil phenotype was also observed in vivo in Tollip deficient mice subjected to DSS-induced colitis. We observed that TUDCA, a compound capable of restoring Tollip cellular function, can potently alleviate the severity of DSS-induced colitis. In humans, we observed significantly reduced Tollip levels in peripheral blood collected from human colitis patients as compared to blood samples from healthy donors. Collectively, our data reveal a novel mechanism in Tollip alteration that underlies the inflamed and incompetent polarization of neutrophils leading to severe outcomes of colitis.

[Efficacy of Yunnan Baiyao as an adjuvant treatment for active ulcerative colitis: an open-label randomized controlled study]

OBJECTIVE

To investigate the efficacy of Yunnan Baiyao (YNBY)as an adjuvant treatment of active ulcerative colitis.

METHODS

A total of 221 patients with active ulcerative colitis were randomized into YNBY group (78 cases) and control group (143 cases). The patients were followed up for 26 weeks and time of remission and serological data (WBC, HGB, PLT, and CRP) were recorded.

RESULTS

The patients receiving YNBY as an adjuvant therapy had a median remission time of 9 weeks (95% CI: 8.293-9.707), significantly shorter than that of 13 weeks (95% CI: 11.855-14.145) in the control patients (P<0.001). According to the extent of the lesion, both YNBY group and control group were classified into E1, E2 and E3 subgroups, and the median remission time was 7 versus 11 weeks in E1 subgroups (P=0.09), 10 versus 13 weeks in E2 subgroups (P=0.04), and 9 versus 14 weeks in E3 subgroups (P<0.001). According to the disease severity, the patients in YNBY group and control group had a median remission time of 9 versus 10 weeks in mild cases (P=0.568), 9 versus 14 weeks in moderate cases (P<0.001), and 11 versus 20 weeks in severe cases (P=0.001). According to the standard treatment received, the median remission time in YNBY group and control group was 9 versus 12 weeks in those receiving mesalazine (P<0.001), 9 versus 13 weeks in those receiving corticosteroid (P=0.001), and 7 versus 14 weeks in those receiving infliximab (P=0.04). Cox proportional hazards regression analysis showed that YNBY was a protective factor for disease remission. The remission time was shortened by 2.283 times (95% CI: 1.69-3.070, P<0.001) in patients having YNBY as an adjuvant treatment compared to the control group.

CONCLUSION

Patients with active ulcerative colitis can benefit from YNBY as an adjuvant treatment, which shortens the time of disease remission, relieves the symptoms and improves the quality of life of the patients.

Subclinical-Dose Endotoxin Sustains Low-Grade Inflammation and Exacerbates Steatohepatitis in High-Fat Diet-Fed Mice

Subclinical circulating bacterial endotoxin LPS has been implicated as an important cofactor in the development and progression of nonalcoholic steatohepatitis, but the underlying mechanisms remain unclear. In this study, we demonstrated that 4-wk injection with superlow-dose LPS significantly promoted neutrophil infiltration and accelerated nonalcoholic steatohepatitis progression, including exacerbated macrovesicular steatosis, inflammation, and hepatocyte ballooning in high-fat diet-fed apolipoprotein E knockout mice. This effect could sustain for a month after stoppage of LPS injection. LPS also significantly increased numbers of apoptotic nuclei in hepatocytes and expressions of proapoptotic regulators. Moreover, LPS sustained the low-grade activation of p38 MAPK and inhibited the expression of the upstream MAPK phosphatase 7. By applying selective inhibitors, we demonstrated that the activation of p38 MAPKs is required for neutrophil migration induced by superlow-dose LPS in vitro. Together, these data suggest that superlow-dose LPS may sustain the low-grade activation of p38 MAPKs and neutrophil infiltration, leading to the exacerbation of steatohepatitis.

Low-grade inflammatory polarization of monocytes impairs wound healing

Impaired wound healing often accompanies low-grade inflammatory conditions, during which circulating levels of subclinical super-low-dose endotoxin may persist. Low-grade inflammatory monocyte polarization may occur during chronic inflammation and deter effective wound repair. However, little is understood about the potential mechanisms of monocyte polarization by sustained insult of subclinical super-low-dose endotoxin. We observed that super-low-dose endotoxin preferentially programmes a low-grade inflammatory monocyte state in vitro and in vivo, as represented by the elevated population of CD11b(+) Ly6C(high) monocytes and sustained expression of CCR5. Mechanistically, super-low-dose endotoxin caused cellular stress, altered lysosome function and increased the transcription factor IRF5. TUDCA, a potent inhibitor of cellular stress, effectively blocked monocyte polarization and improved wound healing in mice injected with super-low-dose endotoxin. Our data revealed the polarization of low-grade inflammatory monocytes by sustained endotoxin challenge, its underlying mechanisms and a potential intervention strategy. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

MTBDRplus results correlate with treatment outcome in previously treated tuberculosis patients

BACKGROUND

Although MTBDRplus is validated for the detection of multidrug-resistant tuberculosis (MDR-TB), its role in the assessment of treatment outcome is less clear. We evaluated the association of MTBDRplus results with treatment outcome in new and previously treated patients in an endemic setting in China and determined factors associated with poor treatment outcomes.

METHODS

We prospectively enrolled 298 smear-positive pulmonary TB patients who received the World Health Organization recommended initial treatment regimen or retreatment regimen. MTBDRplus was compared with conventional drug susceptibility testing and DNA sequencing for the detection of MDR-TB. Treatment responses were monitored using sputum smear, culture and chest radiography.

RESULTS

MTBDRplus successfully identified all MDR-TB and had good concordance with sequencing. MDR-TB rates were low among new patients (4/187, 2.1%), but high in previously treated patients (12/28, 42.9%); 65.2% (15/23) of previously treated cases and 17.1% (27/158) of new cases were unsuccessfully treated (P < 0.001). Seven of eight (87.5%) previously treated MDR-TB patients failed the retreatment regimen. In addition to drug resistance, sputum smear positivity at week 8 and cavitation are associated with treatment failure.

CONCLUSION

Not only did MTBDRplus correctly identify all MDR-TB cases, MTBDRplus results are also associated with treatment outcomes in previously treated patients. The retreatment regimen should no longer be used; treatment should be guided by molecular testing.

Super-low dose endotoxin pre-conditioning exacerbates sepsis mortality

Sepsis mortality varies dramatically in individuals of variable immune conditions, with poorly defined mechanisms. This phenomenon complements the hypothesis that innate immunity may adopt rudimentary memory, as demonstrated in vitro with endotoxin priming and tolerance in cultured monocytes. However, previous in vivo studies only examined the protective effect of endotoxin tolerance in the context of sepsis. In sharp contrast, we report herein that pre-conditioning with super-low or low dose endotoxin lipopolysaccharide (LPS) cause strikingly opposite survival outcomes. Mice pre-conditioned with super-low dose LPS experienced severe tissue damage, inflammation, increased bacterial load in circulation, and elevated mortality when they were subjected to cecal-ligation and puncture (CLP). This is in contrast to the well-reported protective phenomenon with CLP mice pre-conditioned with low dose LPS. Mechanistically, we demonstrated that super-low and low dose LPS differentially modulate the formation of neutrophil extracellular trap (NET) in neutrophils. Instead of increased ERK activation and NET formation in neutrophils pre-conditioned with low dose LPS, we observed significantly reduced ERK activation and compromised NET generation in neutrophils pre-conditioned with super-low dose LPS. Collectively, our findings reveal a mechanism potentially responsible for the dynamic programming of innate immunity in vivo as it relates to sepsis risks.

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Super-low dose endotoxin pre-conditioning exacerbates, while higher dose endotoxin alleviates sepsis mortality.

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Super-low dose endotoxin reduces, while higher dose endotoxin facilitates neutrophil extracellular trap (NET) formation.

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Super-low dose endotoxin suppresses, while higher dose endotoxin induces ERK activation required for NET formation.

Alteration of lysosome fusion and low-grade inflammation mediated by super-low-dose endotoxin

Subclinical super-low-dose endotoxin LPS is a risk factor for the establishment of low-grade inflammation during the pathogenesis and progression of chronic diseases. However, the underlying mechanisms are not well understood. At the cellular level, a disruption of lysosome fusion with endosomes or autophagosomes may contribute to the potentiation of low-grade inflammation. In this study, we identified that subclinical super-low-dose endotoxin LPS can potently inhibit the process of endosome acidification and lysosome fusion with endosomes or autophagosomes in primary macrophages. Super-low-dose LPS induced the inhibitory phosphorylation of VPS34, thus leading to the disruption of endosome-lysosome fusion. This effect may depend upon the clearance and relocation of Tollip in macrophages by super-low-dose LPS. Consistent with this notion, Tollip-deficient macrophages had constitutively elevated levels of VPS34 inhibitory phosphorylation and constitutive disruption of endosome-lysosome fusion. By employing a skin excision wound-healing model, we observed that Tollip-deficient mice had significantly elevated levels of cell stress and reduced wound repair. This study reveals a novel mechanism responsible for the modulation of endosome-lysosome fusion and low-grade inflammation in innate macrophages.

Evaluation of the GenoType® MTBDRplus assay and identification of a rare mutation for improving MDR-TB detection

OBJECTIVE

To assess the new GenoType® MTBDRplus assay for the rapid detection of multidrug-resistant tuberculosis (MDR-TB) in comparison with DNA sequencing to identify drug resistance mutation profiles in China.

DESIGN

Using MTBDRplus, drug susceptibility testing (DST) and DNA sequencing, 237 Mycobacterium tuberculosis strains were tested.

RESULTS

The sensitivity of MTBDRplus was 75.0% (126/168) for isoniazid (INH) resistant strains, and 93.5% (157/168) for rifampicin (RMP) resistant strains. It correlated well with sequencing, with 94.9% and 99.6% agreement for each strain category and 100% specificity for all categories. The two most common rpoB mutations were S531L (53.6%, 90/168) and D516G (17.3%, 29/168) in RMP-resistant strains. INH resistance was dominated by the katG 315 locus (S to T, N, R, I) mutation (73.7%, 124/168), and a rare katG mutation, S315N (6.5%, 11/168), not covered by MTBDRplus was identified. The mutation combination inhA-15/inhA-8 and katG315 (34 strains) was characteristically displayed in MDR-TB strains (23.5%), but not in INH-monoresistant strains.

CONCLUSIONS

Although Genotype MTBDRplus is a rapid and reliable molecular test for detecting MDR-TB, a significant proportion of strains in China contain a rare katG S315N mutation that would be missed by the assay. Further improvements may be achieved by incorporating this mutation into the assay to increase sensitivity in detecting INH resistance in China.