Impact of non-obese metabolic dysfunction-associated fatty liver disease on risk factors for the recurrence of esophageal squamous cell carcinoma treated with endoscopic submucosal dissection: A multicenter study.

AIM: Metabolic dysfunction is a risk factor for esophageal squamous cell carcinoma (ESCC). We investigated the impact of the recently proposed metabolic dysfunction-associated fatty liver disease (MAFLD) and its subtypes on ESCC recurrence after endoscopic treatment. METHODS: This multicenter observational cohort study enrolled consecutive patients newly diagnosed with ESCC after endoscopic treatment. Patients were classified into MAFLD or non-MAFLD groups. The MAFLD group was further classified into non-obese and obese MAFLD groups with a body mass index cutoff value of 25 kg/m2 . The impact of MAFLD on the recurrence of ESCC was evaluated using a decision tree algorithm and random forest analysis. RESULTS: A total of 147 patients (average age 69 years; male : female, 127:20; observational period, 2.4 years) were enrolled. The 1-, 3-, and 5-year recurrence rates were 2.0%, 21.1%, and 33.7%, respectively. Independent risk factors for the recurrence of ESCC were MAFLD (HR 2.2812; 95% confidence interval 1.0497-4.9571; p = 0.0373), drinking status, and smoking status. Metabolic dysfunction-associated fatty liver disease was identified as the second most important classifier for recurrence, followed by drinking status. The cumulative incidence of ESCC recurrence was higher in the MAFLD group than in the non-MAFLD group. In a subanalysis, the cumulative incidence of recurrence was significantly higher in the non-obese than in the obese MAFLD group among abstainers/non-drinkers. Directed acyclic graphs revealed that MAFLD directly contributes to ESCC recurrence. CONCLUSIONS: MAFLD was independently and directly associated with ESCC recurrence after endoscopic treatment; a high recurrence rate was observed in patients with non-obese MAFLD. Metabolic dysfunction-associated fatty liver disease may identify patients at high risk for ESCC recurrence.

Identification of serum and glucocorticoid-regulated kinase 1 as a regulator of signal transducer and activator of transcription 3 signaling.

Signal transducer and activator of transcription 3 (STAT3) plays key roles in cancer cell proliferation, invasion, and immunosuppression. In many human cancer cells, STAT3 is hyperactivated, which leads to tumor progression and drug resistance, and therefore STAT3 and its modulators are considered effective drug targets. However, the complex regulatory mechanisms of STAT3 have made it difficult to develop potent anticancer drugs that suppress its activity. Here, we report serum and glucocorticoid-regulated kinase 1 (SGK1) as a novel regulator of STAT3 signaling and an effective target for combination therapy with Janus kinase (JAK) inhibitors. We screened small molecules using a gain-of-function mutant of STAT3 resistant to JAK inhibition and found that an SGK1 inhibitor suppressed the constitutive activation of STAT3. Importantly, our results revealed that SGK1 also mediated the activation of wild-type STAT3. Further examination suggested that the tuberous sclerosis complex 2 and mammalian target of rapamycin signaling pathway were involved in STAT3 activation by SGK1. Finally, we demonstrated that SGK1 inhibition enhanced the inhibitory effect of a JAK inhibitor on STAT3 phosphorylation and cancer cell proliferation. Our findings provide new insights into the molecular mechanisms of STAT3 activation and suggest SGK1 as a potential target for STAT3-targeted combination cancer therapy.

Evaluation of Serum Calprotectin Levels in Patients with Inflammatory Bowel Disease.

BACKGROUND: Fecal calprotectin has been proposed as a useful biomarker of disease activity in inflammatory bowel disease (IBD). However, the role of calprotectin in systemic circulation is not well established. Thus, this study aimed to quantify serum calprotectin levels to identify a potential inflammatory marker for IBD. METHODS: Ninety-eight patients with ulcerative colitis (UC) and 105 patients with Crohn's disease (CD) were prospectively enrolled and clinically scored. Ninety-two healthy, age-matched subjects served as controls. Blood samples from UC and CD patients and controls were analyzed for serum calprotectin levels and routine laboratory parameters. Disease activity was assessed by partial Mayo score and Harvey-Bradshaw index for UC and CD, respectively. RESULTS: Serum calprotectin levels were higher in CD and UC patients than in controls and were higher during active disease than during inactive disease in CD but not in UC. In UC, serum calprotectin levels were correlated with C-reactive protein (CRP) but not with other laboratory parameters or disease activity. In CD, serum calprotectin levels were positively correlated with disease activity, serum CRP, and platelet count. In UC and CD, serum calprotectin and CRP levels increased during the acute phase and decreased towards remission. CONCLUSIONS: Serum calprotectin is an inflammatory marker in IBD but might be more effective in evaluating patients with CD than those with UC. Further studies are needed to confirm these findings and to better determine the specific uses of serum calprotectin in routine practice.

Evaluation of Serum Leucine-Rich Alpha-2 Glycoprotein as a New Inflammatory Biomarker of Inflammatory Bowel Disease.

Studies on serum leucine-rich alpha-2 glycoprotein (LRG) in inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are scarce; the methods for estimating disease activity are less established, particularly for CD. This study is aimed at evaluating the utility of serum LRG as a potential inflammatory marker for IBD and to investigate the LRG gene expression in peripheral blood mononuclear cells (PBMCs) as a possible source of serum LRG. Overall, 98 patients with UC and 96 patients with CD were prospectively enrolled and clinically evaluated; 92 age-matched individuals served as the healthy controls. The blood samples were analyzed for serum LRG levels and routine laboratory parameters. Disease activity was assessed clinically and endoscopically. Finally, LRG gene expression in the PBMCs from a different cohort (41 patients with UC, 34 patients with CD, and 30 healthy controls) was examined. The serum LRG levels were higher during active disease than during inactive disease; additionally, serum LRG levels were positively correlated with clinical disease activity, C-reactive protein (CRP) levels, and other laboratory parameters in patients with UC and CD and with endoscopic disease activity in UC. UC and CD showed comparable areas under the curve (AUC) values for determining clinical remission and differentiating between endoscopic remission associated with LRG and CRP. The levels of LRG mRNA were also increased in PBMCs from patients with UC and CD and reflected disease activity. These data suggest that serum LRG, originated partially from PBMCs, is an inflammatory marker in UC and CD. A large-scale well-designed study should be conducted in the future to more accurately reveal the clinical significance of LRG in patients with IBD.

Therapeutic Potential of a Self-Assembling Peptide Hydrogel to Treat Colonic Injuries Associated with Inflammatory Bowel Disease.

BACKGROUND AND AIMS: The Self-assembling Peptide Hydrogel [SAPH, PuraMatrix], a fully synthetic peptide solution designed to replace collagen, has recently been used to promote mucosal regeneration in iatrogenic ulcers following endoscopic submucosal dissection. Herein, we evaluated its utility in ulcer repair using a rat model of topical trinitrobenzene sulphonic acid [TNBS]-induced colonic injuries. METHODS: Colonic injuries were generated in 7-week-old rats by injecting an ethanol solution [35%, 0.2 mL] containing 0.15 M TNBS into the colonic lumen. At 2 and 4 days post-injury, the rats were subjected to endoscopy, and SAPH [or vehicle] was topically applied to the ulcerative lesion. Time-of-flight secondary ion mass spectrometry [TOF-SIMS] was used to detect SAPH. Colonic expression of cytokines and wound healing-related factors were assessed using real-time polymerase chain reaction or immunohistochemistry. RESULTS: SAPH treatment significantly reduced ulcer length [p = 0.0014] and area [p = 0.045], while decreasing colonic weight [p = 0.0375] and histological score [p = 0.0005] 7 days after injury. SAPH treatment also decreased colonic expression of interleukin [IL]-1α [p = 0.0233] and IL-6[p = 0.0343] and increased that of claudin-1 [p = 0.0486] and villin [p = 0.0183], and ß-catenin staining [p = 0.0237]. TOF-SIMS revealed lesional retention of SAPH on day 7 post-injury. Furthermore, SAPH significantly promoted healing in in vivo mechanical intestinal wound models. CONCLUSIONS: SAPH application effectively suppressed colonic injury, downregulated inflammatory cytokine expression, and upregulated wound healing-related factor expression in the rat model; thus, it may represent a promising therapeutic strategy for IBD-related colonic ulcers.

Altered serum profile of the interleukin-22 system in inflammatory bowel disease.

BACKGROUND AND AIM: Interleukin-22 (IL-22), plays a vital role in the mucosal repair of inflammatory bowel disease (IBD). Serum levels of IL-22 and IL-22 binding protein (IL-22BP), a soluble inhibitory IL-22 receptor, were measured in patients with IBD to investigate the profile of IL-22 in the systemic circulation. METHODS: Blood samples from 92 healthy subjects, 98 patients with ulcerative colitis (UC), and 105 patients with Crohn's disease (CD) were analyzed for serum levels of IL-22, IL-22BP, human ß-defensin 2 (hBD-2), and serum inflammatory parameters. Disease activity was assessed by the partial Mayo score and Harvey-Bradshaw index for UC and CD, respectively. RESULTS: Serum IL-22 level was lower in UC (P < 0.001) and CD (P < 0.001) vs control and its decrease was more pronounced in CD than in UC (P = 0.019). Serum IL-22BP level was lower in UC (P < 0.001) and CD (P < 0.001) vs control and correlated with inflammatory parameters (albumin and C-reactive protein (CRP) in UC; hemoglobin, albumin, and CRP in CD). Serum IL-22/IL-22BP ratios were higher in UC (P = 0.009) vs control and correlated with inflammatory parameters (albumin and CRP). Serum hBD-2 level was higher only in CD (P = 0.015) but did not correlate with serum IL-22 levels, IL-22BP levels, IL-22/IL-22BP ratios, or inflammatory parameters. CONCLUSIONS: Dysregulation of the IL-22 system in the blood may play a role in the pathogenesis of IBD. Further studies are needed to understand the pathogenic and clinical significance of the blood IL-22 system in IBD.

Gene Expression of Transient Receptor Potential Channels in Peripheral Blood Mononuclear Cells of Inflammatory Bowel Disease Patients.

We examined the expression profile of transient receptor potential (TRP) channels in peripheral blood mononuclear cells (PBMCs) from patients with inflammatory bowel disease (IBD). PBMCs were obtained from 41 ulcerative colitis (UC) patients, 34 Crohn's disease (CD) patients, and 30 normal subjects. mRNA levels of TRP channels were measured using the quantitative real-time polymerase chain reaction, and correlation tests with disease ranking, as well as laboratory parameters, were performed. Compared with controls, TRPV2 and TRPC1 mRNA expression was lower, while that of TRPM2, was higher in PBMCs of UC and CD patients. Moreover, TRPV3 mRNA expression was lower, while that of TRPV4 was higher in CD patients. TRPC6 mRNA expression was higher in patients with CD than in patients with UC. There was also a tendency for the expression of TRPV2 mRNA to be negatively correlated with disease activity in patients with UC and CD, while that of TRPM4 mRNA was negatively correlated with disease activity only in patients with UC. PBMCs from patients with IBD exhibited varying mRNA expression levels of TRP channel members, which may play an important role in the progression of IBD.

Safety and efficacy of single-needle leukocyte apheresis for treatment of ulcerative colitis.

Leukocyte apheresis (LCAP) is a safe and effective treatment for active ulcerative colitis (UC) in Japan. Nevertheless, a limitation of LCAP is its requirement for two puncture sites (double-needle [DN] apheresis), sometimes leading to problems with needle puncture. Single-needle (SN) apheresis is useful in hemodialysis and reduces needle puncture pain. If SN apheresis were found to be useful in LCAP for UC, it may reduce patient burden. The aim of this study was to compare the safety and efficacy of SN apheresis with that of DN apheresis. Twenty-four patients with active UC were retrospectively enrolled. They underwent either SN apheresis (n = 12) or conventional double-needle (DN) apheresis (n = 12) at the Kurume University Hospital from February 2014 to March 2018. At each session, we recorded access problems defined by the time required to initiate apheresis and the frequency of puncture-related problems, as well as blood circuit clotting, defined as clotting necessitating interruption of apheresis and changing of the circuit. Efficacy was assessed using partial Mayo scores. The number of apheresis sessions was comparable between SN and DN apheresis (9.0 ± 2.0 times vs 9.6 ± 1.4 times, mean ± SEM). SN significantly reduced the time required to start apheresis (10.0 ± 5.4 minutes vs 19.4 ± 11.9 minutes, P < .05) as well as needle puncture troubles (0.9% vs 11.5%, P < .05). SN had comparable frequency of blood clotting episodes (5.6% vs 8.7%). SN apheresis had similar clinical efficacy (P < .001 in SN and P < .01 in DN). The improvement and remission rates were comparable between groups. SN apheresis may be safe and effective and may reduce patient burden during UC treatment. Nevertheless, further comparative studies are needed.

[A case of hemobilia due to the rupture of pancreaticoduodenal artery aneurysm with choledocholithiasis].

A 79-year-old male patient had a huge choledocholithiasis that was difficult to remove and underwent endoscopic retrograde biliary drainage. He complained of hematemesis upon admission to our hospital. Endoscopic retrograde cholangiography showed bleeding from the papilla of Vater and revealed an upper filling defect with a large stone in the common bile duct. Furthermore, computed tomography detected an aneurysm close to the stone. Considering the occurrence of a ruptured pancreaticoduodenal artery aneurysm, we diagnosed this condition as hemobilia. Through angiography, we also detected a saccular aneurysm in the posterior superior pancreaticoduodenal artery (PSPDA);subsequently, selective transcatheter arterial embolization (TAE) was performed. However, bleeding persisted after TAE;therefore, we performed second-time embolization for other PSPDA branches. Consequently, hemostasis was achieved. To date, bleeding has not reoccurred. The pancreaticoduodenal artery constitutes a complex arcade;hence, cases of extremely difficult hemostasis by embolization have been reported. Herein, we have presented a life-saving case of choledocholithiasis treated with TAE for biliary bleeding from a PSPDA aneurysm rupture.

Questionnaire Survey from the 1st Kurume University Inflammatory Bowel Disease Center Educational Lecture.

INTRODUCTION: The number of inflammatory bowel disease (IBD) patients is increasing steadily in Japan, and it is expected that patient groups and patient education will improve the quality of life of patients and IBD care. The 1st Kurume University IBD Center educational lecture was held and a questionnaire survey was administered at this lecture. METHODS: We asked 78 participants to answer a questionnaire survey on the occasion of the 1st Kurume University IBD Center educational lecture. RESULTS: We obtained responses from 56 (71.8%) participants; 31 (55.4%) had IBD [21 (37.4%) had ulcerative colitis (UC) and 10 (17.9%) had Crohn's disease (CD)]. Most participants were female (37, 66%). The age range with the highest number of participants was 40 to 69 (27, 48.2%). Most had heard about this educational lecture through "notification by the patient's doctor" 23 (41.1%). A total of 30 (53.6%) of participants answered "good" about the lecture content, while 50 (89.7%) of participants answered "very good" and "good" about the impression of this lecture. Meanwhile, 10 (32.3%) of patients were interested in patient groups. The percentage of patients who were interested in patient groups was higher in patients with CD 4 (66.7%) than those with UC 2 (33.3%). CONCLUSION: We held the 1st Kurume University IBD center educational lecture. Further studies are needed to assess whether educational lectures and/or patient groups can improve patients' quality of life (QOL) and IBD care in our hospital.

The characteristics of nivolumab-induced colitis: an evaluation of three cases and a literature review.

BACKGROUND: The use of immune-checkpoint inhibitors in cancer treatment has become increasingly common, resulting in an increase in the incidence of related side effects. Diarrhoea and colitis have been previously documented as gastrointestinal tract-related side effects of immune-checkpoint inhibitors. Although PD-1/PD-L1 inhibitors produce fewer side effects than CTLA-4 inhibitors, diarrhoea and colitis continue to be reported. However, little is known about the endoscopic features associated with PD-1/PD-L1 inhibitors. In this report, we describe three cases of colitis induced by a PD-1 inhibitor nivolumab. These cases showed endoscopic findings characteristic of ulcerative colitis (UC). Treatment was in accordance with UC therapy, which resulted in beneficial outcomes. CASE PRESENTATION: Three patients with lung cancer treated with nivolumab presented with diarrhoea with (case 2) or without haematochezia (cases 1 and 3). Treatment with nivolumab was ceased and colonoscopy was performed, revealing endoscopic features similar to those of UC. These patients were diagnosed with nivolumab-induced colitis. Case 1 was treated with mesalazine, whereas cases 2 and 3 were treated with corticosteroids. Subsequently, their symptoms improved. CONCLUSIONS: Nivolumab-induced colitis exhibited similar characteristics to UC. Treatment was similar to that for UC and was successful.

Marked accumulation of fluorodeoxyglucose and inflammatory cells expressing glucose transporter-3 in immunoglobulin G4-related autoimmune hepatitis.

Immunoglobulin (Ig)G4-related autoimmune hepatitis (AIH) is a recently proposed subtype that responds well to steroid treatment; however, its pathogenesis remains unclear. We report here a 65-year-old Japanese woman with skin itching and lip swelling. She had liver injury with jaundice, which persisted despite stopping anti-allergic agents. Blood chemistry revealed highly elevated serum IgG and IgG4 (535 mg/dL) levels, and positive anti-nuclear antibody. The diagnosis of AIH was based on liver biopsy. Notably, the IgG4+ /IgG+ cell ratio was 85%. On fluorodeoxyglucose (FDG) positron emission tomography/computed tomography, robust signal intensity was found in the liver, and in enlarged lymph nodes and salivary glands with confirmed IgG4+ cell infiltration. Immunofluorescence analysis of the liver biopsy specimen indicated clear expression of glucose transporter-3 (Glut-3) in IgG4+ inflammatory cells infiltrating into the portal area. This is the first report of simultaneous strong accumulation of FDG and Glut-3 expression in IgG4-related AIH, which might aid in elucidating the pathogenesis of this disease.

Granulocyte-colony stimulating factor producing mucinous cystic neoplasm with an associated invasive carcinoma of the pancreas.

The present case study documents an autopsy case of granulocyte-colony stimulating factor (G-CSF)-producing mucinous cystic neoplasm (MCN), with an associated invasive carcinoma of the pancreas. A 65-year-old woman presented to Omuta City Hospital (Omuta Japan) with a primary complaint of abdominal pain. Multiple liver nodules and a pancreatic cyst were detected upon abdominal computed tomography. Initially, liver abscess was suspected as the patient exhibited leukocytosis and elevated C-reactive protein level. However, the serum concentration of G-CSF was 98.8 pg/ml (normal, <39.0 pg/ml). At 6 weeks after admission, the patient succumbed to liver failure. At autopsy, a cystic lesion was identified in the pancreatic tail that contained bloody necrotic fluid. Microscopically, the cystic lesion was composed of columnar and mucin-producing epithelium associated with ovarian-type subepithelial stroma. The stroma exhibited positive immunostaining for vimentin, estrogen receptor and progesterone receptor. Calcification on the cystic wall was observed. The tumor invaded the pancreatic parenchyma and metastasized to the liver and lungs. The lesion was diagnosed as invasive adenocarcinoma arising in MCN. By contrast, liver nodules predominantly consisted of pleomorphic cancer cells with small foci of adenocarcinoma. Pancreatic and hepatic cancer cells were confirmed to be positive for G-CSF staining. The present case report indicates that G-CSF-producing MCNs may be associated with an aggressive clinical course, particularly when anaplastic changes are observed.

Differentiation of Human Induced Pluripotent Stem Cell (hiPSC)-Derived Neurons in Mouse Hippocampal Slice Cultures.

Potential clinical applications of neurons derived from human induced pluripotent stem cells (hiPSC-neurons) for drug screening and transplantation therapies have received considerable attention. However, it remains unclear whether and how transplanted hiPSC-neurons are incorporated into pre-existing neural circuits. Here we developed a co-culture system of hiPSC-neurons and mouse hippocampal slices to examine the differentiation of hiPSC-neurons in pre-existing neural circuits. hiPSC-neurons transplanted in mouse hippocampal slices expressed the hippocampal neuron-specific markers HuB and Prox1 after 7 days of culture, while those markers were scarcely expressed in hiPSC-neurons cultured on glass dishes. Furthermore, hiPSC-neurons transplanted in the dentate gyrus (DG) of slice cultures grew to exhibit dentate granule cell-like morphologies, including besom-shaped dendrites. Similarly, hiPSC-neurons transplanted in the CA1 region of slice cultures grew to exhibit CA1 pyramidal cell-like morphologies, including primary apical and multiple basal dendrites with synaptic spines. Additionally, these cells projected axons toward the entorhinal cortex (EC) as observed in vivo. These data suggest that hiPSC-neurons were anatomically integrated into pre-existing neural circuits in a region-specific manner. Thus, the co-culture system will be useful for the study of efficient strategies to differentiate transplanted hiPSC-neurons.

Differentiation of oligodendrocyte progenitor cells from dissociated monolayer and feeder-free cultured pluripotent stem cells.

Oligodendrocytes myelinate axons and form myelin sheaths in the central nervous system. The development of therapies for demyelinating diseases, including multiple sclerosis and leukodystrophies, is a challenge because the pathogenic mechanisms of disease remain poorly understood. Primate pluripotent stem cell-derived oligodendrocytes are expected to help elucidate the molecular pathogenesis of these diseases. Oligodendrocytes have been successfully differentiated from human pluripotent stem cells. However, it is challenging to prepare large amounts of oligodendrocytes over a short amount of time because of manipulation difficulties under conventional primate pluripotent stem cell culture methods. We developed a proprietary dissociated monolayer and feeder-free culture system to handle pluripotent stem cell cultures. Because the dissociated monolayer and feeder-free culture system improves the quality and growth of primate pluripotent stem cells, these cells could potentially be differentiated into any desired functional cells and consistently cultured in large-scale conditions. In the current study, oligodendrocyte progenitor cells and mature oligodendrocytes were generated within three months from monkey embryonic stem cells. The embryonic stem cell-derived oligodendrocytes exhibited in vitro myelinogenic potency with rat dorsal root ganglion neurons. Additionally, the transplanted oligodendrocyte progenitor cells differentiated into myelin basic protein-positive mature oligodendrocytes in the mouse corpus callosum. This preparative method was used for human induced pluripotent stem cells, which were also successfully differentiated into oligodendrocyte progenitor cells and mature oligodendrocytes that were capable of myelinating rat dorsal root ganglion neurons. Moreover, it was possible to freeze, thaw, and successfully re-culture the differentiating cells. These results showed that embryonic stem cells and human induced pluripotent stem cells maintained in a dissociated monolayer and feeder-free culture system have the potential to generate oligodendrocyte progenitor cells and mature oligodendrocytes in vitro and in vivo. This culture method could be applied to prepare large amounts of oligodendrocyte progenitor cells and mature oligodendrocytes in a relatively short amount of time.

A single-cell and feeder-free culture system for monkey embryonic stem cells.

Primate pluripotent stem cells (PSCs), including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), hold great potential for research and application in regenerative medicine and drug discovery. To maximize primate PSC potential, a practical system is required for generating desired functional cells and reproducible differentiation techniques. Much progress regarding their culture systems has been reported to date; however, better methods would still be required for their practical use, particularly in industrial and clinical fields. Here we report a new single-cell and feeder-free culture system for primate PSCs, the key feature of which is an originally formulated serum-free medium containing FGF and activin. In this culture system, cynomolgus monkey ESCs can be passaged many times by single-cell dissociation with traditional trypsin treatment and can be propagated with a high proliferation rate as a monolayer without any feeder cells; further, typical PSC properties and genomic stability can be retained. In addition, it has been demonstrated that monkey ESCs maintained in the culture system can be used for various experiments such as in vitro differentiation and gene manipulation. Thus, compared with the conventional culture system, monkey ESCs grown in the aforementioned culture system can serve as a cell source with the following practical advantages: simple, stable, and easy cell maintenance; gene manipulation; cryopreservation; and desired differentiation. We propose that this culture system can serve as a reliable platform to prepare primate PSCs useful for future research and application.

Roquin-2 promotes ubiquitin-mediated degradation of ASK1 to regulate stress responses.

Apoptosis signal-regulating kinase 1 (ASK1, also known as MAP3K5) mediates reactive oxygen species (ROS)-induced cell death. When activated by ROS, ASK1 ultimately becomes ubiquitinated and degraded by the proteasome, a process that is antagonized by the ubiquitin-specific protease USP9X. Using a functional siRNA (small interfering RNA) screen in HeLa cells, we identified Roquin-2 (also called RC3H2) as an E3 ubiquitin ligase required for ROS-induced ubiquitination and degradation of ASK1. In cells treated with H2O2, knockdown of Roquin-2 promoted sustained activation of ASK1 and the downstream stress-responsive kinases JNK (c-Jun amino-terminal kinase) and p38 MAPK (mitogen-activated protein kinase), and led to cell death. The nematode Caenorhabditis elegans produces ROS as a defense mechanism in response to bacterial infection. In C. elegans, mutation of the gene encoding the Roquin-2 ortholog RLE-1 promoted accumulation of the activated form of the ASK1 ortholog NSY-1 and conferred resistance to infection by the bacteria Pseudomonas aeruginosa. Thus, these data suggest that degradation of ASK1 mediated by Roquin-2 is an evolutionarily conserved mechanism required for the appropriate regulation of stress responses, including pathogen resistance and cell death.