Wastewater-based reproduction numbers and projections of COVID-19 cases in three areas in Japan, November 2021 to December 2022

BackgroundWastewater surveillance has expanded globally as a means to monitor spread of infectious diseases. An inherent challenge is substantial noise and bias in wastewater data because of the sampling and quantification process, limiting the applicability of wastewater surveillance as a monitoring tool.AimTo present an analytical framework for capturing the growth trend of circulating infections from wastewater data and conducting scenario analyses to guide policy decisions.MethodsWe developed a mathematical model for translating the observed SARS-CoV-2 viral load in wastewater into effective reproduction numbers. We used an extended Kalman filter to infer underlying transmissions by smoothing out observational noise. We also illustrated the impact of different countermeasures such as expanded vaccinations and non-pharmaceutical interventions on the projected number of cases using three study areas in Japan during 2021-22 as an example.ResultsObserved notified cases were matched with the range of cases estimated by our approach with wastewater data only, across different study areas and virus quantification methods, especially when the disease prevalence was high. Estimated reproduction numbers derived from wastewater data were consistent with notification-based reproduction numbers. Our projections showed that a 10-20% increase in vaccination coverage or a 10% reduction in contact rate may suffice to initiate a declining trend in study areas.ConclusionOur study demonstrates how wastewater data can be used to track reproduction numbers and perform scenario modelling to inform policy decisions. The proposed framework complements conventional clinical surveillance, especially when reliable and timely epidemiological data are not available.

Simultaneous extraction and detection of DNA and RNA from viruses, prokaryotes, and eukaryotes in wastewater using a modified COPMAN

Wastewater surveillance can offer a comprehensive grasp of infectious disease prevalence and human health because wastewater contains various human-derived microbial pathogens, including viruses, bacteria, and fungi. However, methods capable of simultaneous detection of multiple groups of targets in the automated systems and large-scale surveillance are still under development. Here, we demonstrated the modification, involving the addition of bead-beating, to the existing COPMAN (COagulation and Proteolysis method using MAgnetic beads for detection of Nucleic acids in wastewater) enabled enhanced detection of various microorganisms, including SARS-CoV-2. The modified method, termed bead-beating COPMAN (BB-COPMAN), was evaluated through spike-and-recovery experiments and comparative analysis against three previously reported methods for simultaneous DNA/RNA detection. Our study targeted a range of microorganisms, including enveloped and non-enveloped RNA viruses (SARS-CoV-2, PMMoV), a DNA virus (crAssphage), archaea, gram-negative and gram-positive bacteria (E. coli, Lachnospiraceae), antibiotic resistance gene (ampC), and fungi (Candida albicans). The recovery rates of BB-COPMAN for gram-negative and gram-positive bacteria were 17 and 2.1-fold higher, respectively, compared to the method for DNA/RNA detection. Additionally, BB-COPMAN exhibited the highest extraction efficiency among the tested methods, achieving 1.2-5.7 times more DNA and 1.1-69 times more RNA yield on average. BB-COPMAN allowed the detection of SARS-CoV-2 from all nine samples and PMMoV at concentrations 39-97 times higher than other methods. Moreover, BB-COPMAN detected larger amounts of DNA for four out of six DNA targets than the previously reported DNA/RNA detection method. These results demonstrated that BB-COPMAN enables enhanced detection of multiple targets in a single flow of nucleic acid extraction, making the method well-suited for automated systems. In conclusion, BB-COPMAN is a promising method in wastewater surveillance for assessing the prevalence of wide range of pathogenic microorganisms.

Quantitative analysis of SARS-CoV-2 RNA in wastewater and evaluation of sampling frequency during the downward period of a COVID-19 wave in Japan

Wastewater-based epidemiology (WBE) is a practical approach for detecting the presence of SARS-CoV-2 infections and assessing the epidemic trend of the coronavirus disease 2019 (COVID-19). The purpose of this study was to evaluate the minimum sampling frequency required to properly identify the COVID-19 trend during the downward epidemic period when using a highly sensitive RNA detection method. WBE was conducted using the Efficient and Practical virus Identification System with ENhanced Sensitivity for Solids (EPISENS-S), a highly sensitive SARS-CoV-2 RNA detection method, at nine neighboring wastewater treatment plants (WWTPs). These WWTPs were in the same prefecture in Japan, and they had different sewer types, sampling methods, and sampling frequencies. The overall detection rate of SARS-CoV-2 RNA was 97.8 % during the entire study period when the geometric means of new COVID-19 cases per 100,000 inhabitants were between 3.3 and 7.7 in each WWTP. The maximum SARS-CoV-2 RNA concentration in wastewater was 2.14 × 104 copies/L, which corresponded to pepper mild mottle virus (PMMoV)-normalized concentrations of 6.54 × 10-3. We evaluated the effect of sampling frequencies on the probability of a significant correlation with the number of newly reported COVID-19 cases by hypothetically reducing the sampling frequency in the same dataset. When the wastewater sampling frequency occurred 5, 3, 2, and 1 times per week, these results exhibited significant correlations of 100 % (5/5), 89 % (8/9), 85 % (23/27), and 48 % (13/27), respectively. To achieve significant correlation with a high probability of over 85 %, a minimum sampling frequency of twice per week is required, even if sampling methods and sewer types are different. WBE using the EPISENS-S method and a sampling frequency of more than twice a week can be used to properly monitor COVID-19 wave epidemic trends, even during downward periods.

[A Case of Liver Metastasis of Gastric Cancer Successfully Treated with SOX plus Nivolumab]

An 82-year-old, male. He visited his local doctor with a chief complaint of dyspnea on exertion. Anemia was noted, and upper gastrointestinal endoscopy was performed, which revealed an ulcerative lesion in the gastric antrum. A biopsy revealed Group 5, tub2, and HER2 negative, with PD-L1≥5%. cT3N1H1(M1 HEP), cStage ⅣB was diagnosed based on CT scan showing enlarged #8 lymph node and a single liver metastasis in the 2 cm range in S6 of the liver. The patient was deemed unresectable and was started on SOX plus nivolumab therapy. On day 11 after initiation, the patient had Grade 3 diarrhea by CTCAE v5.0, and S-1 was withdrawn for 3 days, but was administered for 2 courses. CT and MRI after chemotherapy showed shrinkage of both the primary tumor and liver metastases; R0 resection was deemed possible, and pyloric gastrectomy, D2 lymph node dissection, and partial hepatic S6 resection were performed. The histological evaluation of response to treatment was Grade 1b, and the patient was in ypStage ⅠA. The patient has been alive without recurrence for 6 months postoperatively while receiving S-1 monotherapy on an outpatient basis.

Economic Evaluation of Wastewater Surveillance Combined with Clinical COVID-19 Screening Tests, Japan

The COVID-19 pandemic has imposed substantial burdens on the global society. To find an optimal combination of wastewater surveillance and clinical testing for tracking COVID-19, we evaluated the economic efficiency of hypothetical screening options at a single facility in Japan. To conduct cost-benefit analyses, we developed standard decision models in which we assumed model parameters from literature and primary data, such as screening policies used at the Tokyo Olympic and Paralympic Village in 2021. We compared hypothetical 2-step screening options that used clinical PCR to diagnose COVID-19 after a positive result from primary screening using antigen tests (option 1) or wastewater surveillance (option 2). Our simulation results indicated that option 2 likely would be economically more justifiable than option 1, particularly at lower incidence levels. Our findings could help justify and promote the use of wastewater surveillance as a primary screening at a facility level for COVID-19 and other infectious diseases.

Near full-automation of COPMAN using a LabDroid enables high-throughput and sensitive detection of SARS-CoV-2 RNA in wastewater as a leading indicator

Wastewater-based epidemiology (WBE) is a promising tool to efficiently monitor COVID-19 prevalence in a community. For WBE community surveillance, automation of the viral RNA detection process is ideal. In the present study, we achieved near full-automation of a previously established method, COPMAN (COagulation and Proteolysis method using MAgnetic beads for detection of Nucleic acids in wastewater), which was then applied to detect SARS-CoV-2 in wastewater for half a year. The automation line employed the Maholo LabDroid and an automated-pipetting device to achieve a high-throughput sample-processing capability of 576 samples per week. SARS-CoV-2 RNA was quantified with the automated COPMAN using samples collected from two wastewater treatment plants in the Sagami River basin in Japan between 1 November 2021 and 24 May 2022, when the numbers of daily reported COVID-19 cases ranged from 0 to 130.3 per 100,000 inhabitants. The automated COPMAN detected SARS-CoV-2 RNA from 81 out of 132 samples at concentrations of up to 2.8 × 10⁵ copies/L. These concentrations showed direct correlations with subsequently reported clinical cases (5-13 days later), as determined by Pearson's and Spearman's cross-correlation analyses. To compare the results, we also conducted testing with the EPISENS-S (Efficient and Practical virus Identification System with ENhanced Sensitivity for Solids, Ando et al., 2022), a previously reported detection method. SARS-CoV-2 RNA detected with EPISENS-S correlated with clinical cases only when using Spearman's method. Our automated COPMAN was shown to be an efficient method for timely and large-scale monitoring of viral RNA, making WBE more feasible for community surveillance.

Identification of SARS-CoV-2 variants in wastewater using targeted amplicon sequencing during a low COVID-19 prevalence period in Japan

Wastewater-based epidemiology is expected to be able to identify SARS-CoV-2 variants at an early stage via next-generation sequencing. In the present study, we developed a highly sensitive amplicon sequencing method targeting the spike gene of SARS-CoV-2, which allows for sequencing viral genomes from wastewater containing a low amount of virus. Primers were designed to amplify a relatively long region (599 bp) around the receptor-binding domain in the SARS-CoV-2 spike gene, which could distinguish initial major variants of concern. To validate the methodology, we retrospectively analyzed wastewater samples collected from a septic tank installed in a COVID-19 quarantine facility between October and December 2020. The relative abundance of D614G mutant in SARS-CoV-2 genomes in the facility wastewater increased from 47.5 % to 83.1 % during the study period. The N501Y mutant, which is the characteristic mutation of the Alpha-like strain, was detected from wastewater collected on December 24, 2020, which agreed with the fact that a patient infected with the Alpha-like strain was quarantined in the facility on this date. We then analyzed archived municipal wastewater samples collected between November 2020 and January 2021 that contained low SARS-CoV-2 concentrations ranging from 0.23 to 0.43 copies/qPCR reaction (corresponding to 3.30 to 4.15 log₁₀ copies/L). The targeted amplicon sequencing revealed that the Alpha-like variant with D614G and N501Y mutations was present in municipal wastewater collected on December 4, 2020 and later, suggesting that the variant had already spread in the community before its first clinical confirmation in Japan on December 25, 2020. These results demonstrate that targeted amplicon sequencing of wastewater samples is a powerful surveillance tool applicable to low COVID-19 prevalence periods and may contribute to the early detection of emerging variants.

Impact of the COVID-19 pandemic on the prevalence of influenza A and respiratory syncytial viruses elucidated by wastewater-based epidemiology

Since the COVID-19 pandemic, a decrease in the prevalence of Influenza A virus (IAV) and respiratory syncytial virus (RSV) has been suggested by clinical surveillance. However, there may be potential biases in obtaining an accurate overview of infectious diseases in a community. To elucidate the impact of the COVID-19 on the prevalence of IAV and RSV, we quantified IAV and RSV RNA in wastewater collected from three wastewater treatment plants (WWTPs) in Sapporo, Japan, between October 2018 and January 2023, using highly sensitive EPISENS™ method. From October 2018 to April 2020, the IAV M gene concentrations were positively correlated with the confirmed cases in the corresponding area (Spearman's r = 0.61). Subtype-specific HA genes of IAV were also detected, and their concentrations showed trends that were consistent with clinically reported cases. RSV A and B serotypes were also detected in wastewater, and their concentrations were positively correlated with the confirmed clinical cases (Spearman's r = 0.36-0.52). The detection ratios of IAV and RSV in wastewater decreased from 66.7 % (22/33) and 42.4 % (14/33) to 4.56 % (12/263) and 32.7 % (86/263), respectively in the city after the COVID-19 prevalence. The present study demonstrates the potential usefulness of wastewater-based epidemiology combined with the preservation of wastewater (wastewater banking) as a tool for better management of respiratory viral diseases.

Wastewater-based prediction of COVID-19 cases using a highly sensitive SARS-CoV-2 RNA detection method combined with mathematical modeling

Wastewater-based epidemiology (WBE) has the potential to predict COVID-19 cases; however, reliable methods for tracking SARS-CoV-2 RNA concentrations (C_RNA) in wastewater are lacking. In the present study, we developed a highly sensitive method (EPISENS-M) employing adsorption-extraction, followed by one-step RT-Preamp and qPCR. The EPISENS-M allowed SARS-CoV-2 RNA detection from wastewater at 50 % detection rate when newly reported COVID-19 cases exceed 0.69/100,000 inhabitants in a sewer catchment. Using the EPISENS-M, a longitudinal WBE study was conducted between 28 May 2020 and 16 June 2022 in Sapporo City, Japan, revealing a strong correlation (Pearson's r = 0.94) between C_RNA and the newly COVID-19 cases reported by intensive clinical surveillance. Based on this dataset, a mathematical model was developed based on viral shedding dynamics to estimate the newly reported cases using C_RNA data and recent clinical data prior to sampling day. This developed model succeeded in predicting the cumulative number of newly reported cases after 5 days of sampling day within a factor of √2 and 2 with a precision of 36 % (16/44) and 64 % (28/44), respectively. By applying this model framework, another estimation mode was developed without the recent clinical data, which successfully predicted the number of COVID-19 cases for the succeeding 5 days within a factor of √2 and 2 with a precision of 39 % (17/44) and 66 % (29/44), respectively. These results demonstrated that the EPISENS-M method combined with the mathematical model can be a powerful tool for predicting COVID-19 cases, especially in the absence of intensive clinical surveillance.

COPMAN: A novel high-throughput and highly sensitive method to detect viral nucleic acids including SARS-CoV-2 RNA in wastewater

During the coronavirus disease 2019 (COVID-19) pandemic, wastewater-based epidemiology (WBE) attracted attention as an objective and comprehensive indicator of community infection that does not require individual inspection. Although several severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection methods from wastewater have been developed, there are obstacles to their social implementation. In this study, we developed the COPMAN (Coagulation and Proteolysis method using Magnetic beads for detection of Nucleic acids in wastewater), an automatable method that can concentrate and detect multiple types of viruses from a limited volume (∼10 mL) of wastewater. The COPMAN consists of a high basicity polyaluminum chloride (PAC) coagulation process, magnetic bead-based RNA purification, and RT-preamplification, followed by qPCR. A series of enzymes exhibiting a high tolerance to PCR inhibitors derived from wastewater was identified and employed in the molecular detection steps in the COPMAN. We compared the detectability of viral RNA from 10-mL samples of virus-spiked (heat-inactivated SARS-CoV-2 and intact RSV) or unspiked wastewater by the COPMAN and other methods (PEG-qPCR, UF-qPCR, and EPISENS-S). The COPMAN was the most efficient for detecting spiked viruses from wastewater, detecting the highest level of pepper mild mottle virus (PMMoV), a typical intrinsic virus in human stool, from wastewater samples. The COPMAN also successfully detected indigenous SARS-CoV-2 RNA from 12 samples of wastewater at concentrations of 2.2 × 10⁴ to 5.4 × 10⁵ copies/L, during initial stages of an infection wave in the right and the left bank of the Sagami River in Japan (0.65 to 11.45 daily reported cases per 100,000 people). These results indicate that the COPMAN is suitable for detection of multiple pathogens from small volume of wastewater in automated stations.

[A Case of Giant Abdominal Desmoid Tumor in a Young Man]

Desmoid tumor is a rare tumor of the soft tissue. The frequency of occurrence is 2.4 to 4.3 cases per year per million people, which is a very rare disease. We experienced a huge intra-abdominal desmoid tumor which is thought to be the primary mesentery. The case was a male in his 20s. He visited a nearby doctor with a complaint of abdominal bloating and abdominal pain. Abdominal contrast CT revealed a huge abdominal mass with a clear boundary of 35×25 cm in size extending from the upper right abdomen to the pelvis. Surgery was performed with a diagnosis of an intra-abdominal mass. Open abdominal tumor resection. Due to infiltration into the duodenum, transverse colon, and pancreas, right hemicolectomy and duodenal combined resection were performed. The pathological diagnosis was a diagnosis of desmoid tumor.

[A Case of Primary Hepatic Mucosa-Associated Lymphoid Tissue Lymphoma]

A 74-year-old man with no chronic liver disease was admitted for an incidental liver tumor by computed tomography. Serological examinations for hepatitis B and C virus were negative and tumor markers, including carcinoembryonic antigen, α-fetoprotein, carbohydrate antigen 19-9, and des-gamma-carboxy prothrombin, were within the normal range. The contrast- enhanced magnetic resonance imaging revealed that the 26 mm in diameter patchy tumor occupied the S7 in the liver. The tumor boundary was enhanced slightly in the arterial phase and inside gradually in the portal phase, and the enhancement was faded in the late phase. As a characteristic finding, vessels penetrated the tumor. The tumor was diagnosed as cholangiocarcinoma, and the patient underwent right lateral sectionectomy. After 19 days postoperatively, the patient was discharged. The diagnosis of hepatic mucosa-associated lymphoid tissue(MALT)lymphoma was made by pathological examination. Currently, the patient has no recurrence for 5 months without adjuvant chemotherapy. The primary hepatic MALT lymphoma is a rare disease among primary hepatic malignant lymphomas. The patient must be followed up carefully because 2 cases were reported as recurrent cases after several years postoperatively although the disease has a good prognosis.

[A Case of Giant Pancreatic Mucinous Cystic Neoplasm That Was Difficult to Preoperative Diagnosis]

A 43-year-old woman with about abdominal distension was referred to our hospital for a more detailed examination. Abdominal CT showed 27 cm-sized cystic lesion with the calcification along the partition wall and a nodular hyperplasia. We suspected pancreatic pseudocyst, primary retroperitoneal tumor and we performed tumorectomy. The resected specimen had a maximum diameter of 27 cm. The histopathological diagnosis was mucinous cystadenocarcinoma of the pancreas with ovarian-type stroma. The adjuvant chemotherapy treated with gemcitabine was selected for 3 courses. She continues to do well without any recurrences 7 months later.

[A Case of Gastric Cancer Performed Curative Operation after Nivolumab]

A 69-year-old man was admitted for the severe anemia. Upper gastrointestinal endoscopy revealed type 3 gastric cancer (por1, HER2 negative)that spread from EG junction to the lesser curvature of lower gastric body. CT revealed LNs metastasis and the direct invasion to the diaphragm. We diagnosed the locally advanced gastric cancer(T4bN[+]M0, Stage ⅣA) and planed neoadjuvant chemotherapy. After 3 courses of S-1 plus CDDP therapy, serum CEA level increased. And the invasion to diaphragm was unclear although the tumor shrunk. After 3 courses of nab-PTX plus RAM therapy as the second- line, the tumor was PD. As the third-line chemotherapy, nivolumab therapy was repeated up to a total of 15 courses. As the tumor was PR, the patient underwent total gastrectomy with D2 lymphadenectomy. The histopathological examination revealed that the cancer invaded into the muscle layer without lymph nodes metastasis. The cancer was diagnosed as pT2 (MP)N0M0, Stage ⅠB. The cancer cells were EB virus positive and MSI-high. CD 8 positive T lymphocytes infiltrated into the stroma. The patient is alive 26 months without adjuvant chemotherapy. The curative operation was able to perform because the infiltrative CD8 positive T lymphocytes reactivated with nivolumab responded remarkably.

[Long-Term Survival following Multidisciplinary Therapy for Unresectable Pancreatic Body Cancer]

A 57-year-old man was diagnosed with a tumor in the pancreatic body at a nearby hospital and consulted our hospital. Examinations revealed that carbohydrate antigen 19-9(CA19-9)levels were 1,765.0 U/mL. We confirmed metastatic liver tumors in S4 and S8 of the liver by EOB-MRI. We diagnosed unresectable pancreatic cancer(T3N0M1, cStage Ⅳ)and administered 10 courses of gemcitabine(GEM)plus nab-paclitaxel(nab-PTX)therapy. The main lesion and the lesion in S4 subsequently disappeared, and the lesion in S8 degenerated into a cyst. CA19-9 levels were 113 U/mL. Surgery was determined as the best course of action after normalizing CA19-9 levels. Therefore, we further administered 6 courses of FOLFIRINOX therapy and 4 courses of GEM plus nab-PTX therapy, but CA19-9 was not normalized. We decided that it would be difficult to normalize CA19-9, and thus proceeded with surgery. During the operation, cystic degenerative lesions were found in S8 and peritoneal dissemination was found in the transverse mesentery. Because the ascites cytopathology was negative, it was judged that the peritoneal dissemination was localized. We performed distal pancreatectomy(D2)plus partial hepatectomy(S8)plus peritoneal dissemination resection. On day 52 after surgery, we resumed GEM plus nab-PTX. The patient has survived without any recurrence for 3 years after the initial surgery.

[A Case of Laparoscopically Resected Sigmoid Colon Cancer and Transverse Colon Mesentery Primary Solitary Fibrous Tumor]

The patient is a 52-year-old woman who visited the general practitioner because of positive fecal occult blood test by medical examination. The patient underwent colonoscopy at the hospital, which revealed sigmoid colon cancer. Therefore, the patient was referred to our hospital for surgery. Preoperative CT scan revealed a well-defined and lobulated 54 mm tumor on the caudal side of the duodenal third portion. On MRI, the tumor showed low T1-weighted image signal and high T2-weighted and diffusion-weighted images signal, with low ADC. For preoperative diagnosis, we diagnosed sigmoid colon cancer and transverse colon mesenteric and performed laparoscopic sigmoid colon and transverse colon mesenteric tumor resections. The histopathological tumor diagnoses were sigmoid colon cancer(S, type 2, 30×30 mm, 1/2 circumference, moderately differentiated adenocarcinoma, pT3[SS], INF b, Ly1a, V1a, pN1b[#252: 2/4], sM0, fStage Ⅲb)and transverse colon mesentery primary solitary fibrous tumor. The patient was treated with XELOX as the adjuvant chemotherapy and survived without recurrence until present.

The detectability and removal efficiency of SARS-CoV-2 in a large-scale septic tank of a COVID-19 quarantine facility in Japan

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is known to be present in sewage, and wastewater-based epidemiology has attracted much attention. However, the physical partitioning of SARS-CoV-2 in wastewater and the removal efficiency of treatment systems require further investigation. This study aimed to investigate the detectability and physical partitioning of SARS-CoV-2 in wastewater and assess its removal in a large-scale septic tank employing anaerobic, anoxic, and oxic processes in a sequential batch reactor, which was installed in a coronavirus disease 2019 (COVID-19) quarantine facility. The amount of SARS-CoV-2 RNA in wastewater was determined with polyethylene glycol (PEG) precipitation followed by quantitative polymerase chain reaction (qPCR), and the association of SARS-CoV-2 with wastewater solids was evaluated by the effect of filtration prior to PEG precipitation (pre-filtration). The amount of SARS-CoV-2 RNA detected from pre-filtered samples was substantially lower than that of samples without pre-filtration. These results suggest that most SARS-CoV-2 particles in wastewater are associated with the suspended solids excluded by pre-filtration. The removal efficiency of SARS-CoV-2 in the septic tank was evaluated based on the SARS-CoV-2 RNA concentrations in untreated and treated wastewater, which was determined by the detection method optimized in this study. Escherichia coli and pepper mild mottle virus (PMMoV) were also quantified to validate the wastewater treatment system's performance. The mean log₁₀ reduction values of SARS-CoV-2, E. coli, and PMMoV were 2.47 (range, 2.25-2.68), 2.81 (range, 2.45-3.18), and 0.66 (range, 0.61-0.70), respectively, demonstrating that SARS-CoV-2 removal by the wastewater treatment system was comparable to or better than the removal of fecal indicators. These results suggest that SARS-CoV-2 can be readily removed by the septic tank. This is the first study to determine the removal efficiency of SARS-CoV-2 in a facility-level sequencing batch activated sludge system.

The Efficient and Practical virus Identification System with ENhanced Sensitivity for Solids (EPISENS-S): A rapid and cost-effective SARS-CoV-2 RNA detection method for routine wastewater surveillance

Wastewater-based epidemiology has attracted attention as a COVID-19 surveillance tool. Here, we developed a practical method for detecting SARS-CoV-2 RNA in wastewater (the EPISENS-S method), which employs direct RNA extraction from wastewater pellets formed via low-speed centrifugation. The subsequent multiplex one-step RT-preamplification reaction with forward and reverse primers for SARS-CoV-2 and a reverse primer only for pepper mild mottle virus (PMMoV) allowed for qPCR quantification of the targets with different abundances in wastewater from the RT-preamplification product. The detection sensitivity of the method was evaluated using wastewater samples seeded with heat-inactivated SARS-CoV-2 in concentrations of 2.11 × 10³ to 2.11 × 10⁶ copies/L. The results demonstrated that the sensitivity of the EPISENS-S method was two orders of magnitude higher than that of the conventional method (PEG precipitation, followed by regular RT-qPCR; PEG-QVR-qPCR). A total of 37 untreated wastewater samples collected from two wastewater treatment plants in Sapporo, Japan when 1.6 to 18 new daily reported cases per 100,000 people were reported in the city (March 4 to July 8, 2021), were examined using the EPISENS-S method to confirm its applicability to municipal wastewater. SARS-CoV-2 RNA was quantified in 92 % (34/37) of the samples via the EPISENS-S method, whereas none of the samples (0/37) was quantifiable via the PEG-QVR-qPCR method. The PMMoV concentrations measured by the EPISENS-S method ranged from 2.60 × 10⁶ to 1.90 × 10⁸ copies/L, and the SARS-CoV-2 RNA concentrations normalized by PMMoV ranged from 5.71 × 10^-6 to 9.51 × 10^-4 . The long-term trend of normalized SARS-CoV-2 RNA concentration in wastewater was consistent with that of confirmed COVID-19 cases in the city. These results demonstrate that the EPISENS-S method is highly sensitive and suitable for routine COVID-19 wastewater surveillance.

COVID-19 wastewater surveillance implemented in the Tokyo 2020 Olympic and Paralympic Village

Wastewater-based epidemiology was implemented in the Olympic and Paralympic Village to better understand COVID-19 incidence. SARS-CoV-2 RNA was detected in a number of wastewater samples even when no positive individual was identified in the corresponding areas. Wastewater-based epidemiology can be a useful tool to control infections at mass gatherings.

[A Case of Pancreas Neuroendocrine Carcinoma Achieved Long-Term Survival by Carboplatin plus Etoposide Therapy]

A 70-year-old man with the history of diabetes mellitus complained of lower abdominal discomfort. Abdominal ultrasonography revealed a pancreatic mass. Contrast enhanced CT showed a 2.6 cm-enhanced tumor ventral to the pancreatic head. It was diagnosed with a pancreatic neuroendocrine carcinoma(PanNEC-G3)by EUS-FNA. The patient underwent pancreatoduodenectomy with the wedge resection of the portal vein and partial resection of the transverse colon. We administered 6 cycles of adjuvant therapy with CDDP plus CPT-11. With the presentation of lymph node metastases and the local recurrence in the anastomotic site of the transverse colon 15 months after surgery, the patient received carboplatin plus etoposide(CE)therapy. Although local recurrence completely responded to the CE therapy, bone metastases were detected 27 months after surgery. Metastatic lesion did not respond to systemic chemotherapy including gemcitabine plus nab-paclitaxel and nal-IRI plus 5-FU/LV, and the patient eventually died 37 months after the surgery. PanNECs represent for less than 1% of all pancreatic tumor. They are characterized by high malignant potential and short time survival with the reported OS of 8.5 to 21 months. This case served as an important reminder to consider multimodal treatment for PanNEC patients to obtain longer survival.

Redundant roles of EGFR ligands in the ERK activation waves during collective cell migration

By knocking out all four EGFR ligands expressed in MDCK cells, this study shows the redundant and specific roles of each EGFR ligand in the ERK activation waves during collective cell migration.

Epidermal growth factor receptor (EGFR) plays a pivotal role in collective cell migration by mediating cell-to-cell propagation of extracellular signal-regulated kinase (ERK) activation. Here, we aimed to determine which EGFR ligands mediate the ERK activation waves. We found that epidermal growth factor (EGF)–deficient cells exhibited lower basal ERK activity than the cells deficient in heparin-binding EGF (HBEGF), transforming growth factor alpha (TGFα) or epiregulin (EREG), but all cell lines deficient in a single EGFR ligand retained the ERK activation waves. Surprisingly, ERK activation waves were markedly suppressed, albeit incompletely, only when all four EGFR ligands were knocked out. Re-expression of the EGFR ligands revealed that all but HBEGF could restore the ERK activation waves. Aiming at complete elimination of the ERK activation waves, we further attempted to knockout NRG1, a ligand for ErbB3 and ErbB4, and found that NRG1-deficiency induced growth arrest in the absence of all four EGFR ligand genes. Collectively, these results showed that EGFR ligands exhibit remarkable redundancy in the propagation of ERK activation waves during collective cell migration.

[A Case of Esophageal Neuroendocrine Carcinoma(NEC)Treated with Collective Treatment]

A 68-year-old man presented to our hospital. An upper gastrointestinal tract endoscopy performed elsewhere revealed an elevated lesion with a circumferential esophageal cancer(identified as small cell carcinoma). Perthe treatment forsmall cell cancer and the standard treatment for esophageal neuroendocrine carcinoma, 7 courses of CBDCA(5mg/m2)plus ETP (100mg/m2)were administered. The lesion shrank and the lymph node swelling disappeared and the patient was deemed to be in partial remission. Nine months later, however, the primary tumor increased in size. A transthoracic subtotal esophagectomy( laparoscope-assisted), 2 area dissection, and gastric tube reconstruction(post-sternal)were performed at 2 years and 10 months afterdiagnosis.

[A Case of Long-Term Survival with Far Advanced Gastric Cancer after Multidisciplinary Treatments, including Conversion Surgery]

An 82-year-old man with Stage Ⅳ advanced gastric cancer and multiple liver metastases was referred to our hospital. Chemotherapy using S-1 was administered, resulting in withdrawal from the usual course because of an adverse event of grade 4 anorexia. GIS and EOB-MRI showed a prominent tumor reduction in both lesions; however, despite this, distal gastrectomy, D2 lymph node dissection, liver biopsy for S3 lesion, partial liver resection for S6 lesion, and cholecystectomy were performed to obtain a therapeutic diagnosis. Pathology revealed that the tumor cells remained in the main liver metastatic lesions. Therapeutic effect was assessed as Grade 2. Although weekly paclitaxel followed by reduced S-1 dosage was introduced after surgery, the recurrent mass was observed in the para-aortic region after 2 years. Subsequently, para-aortic lymph node dissection was performed because no new lesion was detected. More than 10 years have passed without any recurrence since the first surgery. As part of a multidisciplinary treatment for far advanced gastric cancer with multiple liver metastases (Stage Ⅳ), conversion surgery might be considered effective.

[HER2-Positive Advanced Gastric Cancer with Para-Aortic Lymph Node Metastases Treated with Conversion Surgery after Chemotherapy-A Case Report]

A 56-year-old woman diagnosed with type 2 gastric cancer and multiple lymph node metastases(T3N3M1[lym], cStage Ⅳ)was treated with chemotherapy using trastuzumab with S-1 plus cisplatin for 6 cycles. The primary lesion showed PR, and lymph node metastases disappeared after the chemotherapy. Because of adverse events, she was administered with 2 additional cycles of trastuzumab with S-1 plus cisplatin and 6 cycles of trastuzumab with capecitabine plus oxaliplatin. However, the primary lesion increased in size. Therefore, she underwent distal gastrectomy and D1+ lymphadenectomy with para-aortic lymph node sampling as a conversion surgery. The pathological diagnosis was T2N0M0, pStage ⅠB, and the primary cancer was Grade 1a owing to the chemotherapeutic effect. She survives without recurrence or postoperative adjuvant therapies 3 years after the surgery.

[A Resected Case of Rectal Metastasis from Gastric Cancer]

An 82-year-oldwoman previously underwent total gastrectomy for gastric cancer at the age of 75 years. After 7 years of follow-up, a colonoscopy was performedto investigate the cause of constipation, which revealedan irregularity in the rectal submucosa. A colonoscopy-guidedbiopsy showedpoorly differentiatedad enocarcinoma, andthe immunohistochemical staining pattern showedMUC2(-), MUC5AC(+), CDX2(+), andCA1 25(-). FDG-PET showedintense uptake only at the rectum. Thus, laparoscopic high anterior resection was performed. Pathological findings showed that poorly differentiated adenocarcinoma and signet-ring cell carcinoma hadd evelopedmainly in the submucosa. In comparison with the immunohistological features of the previous gastric cancer, the rectal tumor hadsimilar morphological characteristics. The definitive diagnosis was rectal metastasis from gastric cancer. She has remained recurrence-free in the 20 months since this operation.

[A Case of Far-Advanced Esophageal Cancer with Multiple Metastases Showing Long-Term Survival after Chemotherapy]

A 71-year-oldman with voice hoarseness was referredto our hospital for further examination. He was diagnosedwith unresectable Stage Ⅳb esophageal cancer, with direct invasion to the aorta andtrachea andmultiple metastases to the lymph nodes, lungs, and adrenal gland. Because his performance status(PS)was deemedto be favorable, he receivedchemotherapy with docetaxel(DOC), cisplatin, and5 -FU(DCF therapy). After 2 cycles of DCF therapy, the primary lesion was scarred. No malignant lesions were detected in the biopsy performed. No distant metastases were identified on PET-CT. As a subsequent treatment, S-1 plus DOC therapy was administered. Finally, single S-1 administration was continued. The treatment periodwas 14 months. Treatment was concludedbecause a complete response(CR)was maintained. Three years after the conclusion of treatment, CR remains maintained. The overall survival in cases of unresectable advanced esophageal cancer is saidto be 3-10 months, but there are remarkable cases such as this one. If a goodPS is maintained, treatment shouldbe actively considered because CR is possible.

Abstract 4424: Micro-RNA mediated deregulation of hHB-EGF in ovarian cancer

Background: Aberrant expression of microRNAs (miRNAs) has been implicated in human carcinogenesis where they function as oncogenes or tumor suppressor genes. Overexpression of HB-EGF, member of the epidermal growth factor (EGF) family, plays pivotal role in ovarian carcinogenesis. However the molecular mechanisms underlying miRNA(s) mediated aberrant function of HB-EGF in ovarian carcinoma remain unresolved. Here, we investigated the miRNA(s) mediated deregulation of HB-EGF in human ovarian carcinogenesis.

Methods: Web-based bioinformatics algorithms were used to identify candidate miRNAs with putative binding sites on target hHB-EGF mRNA. Expression of miRNAs and mRNA were checked by real-time PCR whereas protein expression was investigated by western blotting assay. Luciferase reporter assay was carried out to examine miR-27a target on 3´UTR of hHB-EGF mRNA. Changes in the oncogenic effects of HB-EGF were studied after gain/loss -of-function of the miR-27a using soft agar colony formation assay and 3D collagen culture. In vivo tumor growth potential of miR-27a was measured in BALB/c nude mice.

Results: By using web-based bioinformatics algorithms 11 miRNAs ((miR-27a/b, -29a/b/c, -96, -128, -132, -182,-194, -212) having putative binding sites on the 3′UTR of hHB-EGF mRNA have been selected for further analysis. Among the putative candidates miR-27a showed maximum reciprocal expression with hHB-EGF and thus we selected miR-27a as promising candidate for hHB-EGF regulation. Overexpression of miR-27a significantly inhibited the hHB-EGF expression in SKOV3 cells by almost 50% and miR-27a inhibitors (anti-miR-27a) upregulated the expression of endogenous hHB-EGF mRNA whereas miR-27a overexpression decreased hHB-EGF protein level in MCAS cells suggesting that miR-27a modulate endogenous hHB-EGF expression both at mRNA and protein level. Luciferase reporter assay revealed that miR-27a directly targets 3´UTR of hHB-EGF mRNA at the predicted site. Ectopic expression of miR-27a suppresses in-vitro growth of SKOV3 ovarian cancer cells. In addition, in-vivo tumorigenecity of SKOV3 cells was also inhibited by miR-27a treatment.

Conclusion: The current study has identified novel miR-27a that negatively regulates hHB-EGF expression by directly targeting 3`UTR of its mRNA. This miR-27a might act as oncosupressor in human epithelial ovarian cancer.

Citation Format: Md. Mustafizur Rahman, Razia Sultana, Ryo Iwamoto, Eisuke Mekada. Micro-RNA mediated deregulation of hHB-EGF in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4424.

Improvement of Xylose Fermentation Ability under Heat and Acid Co-Stress in Saccharomyces cerevisiae Using Genome Shuffling Technique

Xylose-assimilating yeasts with tolerance to both fermentation inhibitors (such as weak organic acids) and high temperature are required for cost-effective simultaneous saccharification and cofermentation (SSCF) of lignocellulosic materials. Here, we demonstrate the construction of a novel xylose-utilizing Saccharomyces cerevisiae strain with improved fermentation ability under heat and acid co-stress using the drug resistance marker-aided genome shuffling technique. The mutagenized genome pools derived from xylose-utilizing diploid yeasts with thermotolerance or acid tolerance were shuffled by sporulation and mating. The shuffled strains were then subjected to screening under co-stress conditions of heat and acids, and the hybrid strain Hyb-8 was isolated. The hybrid strain displayed enhanced xylose fermentation ability in comparison to both parental strains under co-stress conditions of heat and acids. Hyb-8 consumed 33.1 ± 0.6 g/L xylose and produced 11.1 ± 0.4 g/L ethanol after 72 h of fermentation at 38°C with 20 mM acetic acid and 15 mM formic acid. We also performed transcriptomic analysis of the hybrid strain and its parental strains to screen for key genes for multiple stress tolerances. We found that 13 genes, including 5 associated with cellular transition metal ion homeostasis, were significantly upregulated in Hyb-8 compared to levels in both parental strains under co-stress conditions. The hybrid strain Hyb-8 has strong potential for cost-effective SSCF of lignocellulosic materials. Moreover, the transcriptome data gathered in this study will be useful for understanding the mechanisms of multiple tolerance to high temperature and acids in yeast and facilitate the development of robust yeast strains for SSCF.

Therapeutic effects of flurbiprofen axetil on mesenteric traction syndrome: randomized clinical trial

Background

This study aimed to reveal the appropriate timing for the intravenous administration of flurbiprofen axetil for preventing mesenteric traction syndrome (MTS), caused by prostacyclin release.

Methods

In this prospective, randomized, clinical study, forty-five patients who were undergoing elective surgery for colorectal cancer via laparotomy were enrolled. Patients were randomly divided into 3 groups: a preoperative group (n = 16) receiving flurbiprofen axetil directly before surgery; a post-MTS group (n = 14) receiving following MTS onset; and a control group (n = 15) who were not administered flurbiprofen axetil. 6-keto-PGF1α, a stable metabolite of prostacyclin, levels were measured and mean blood pressures were recorded.

Results

In the preoperative group, 6-keto-PGF1α levels did not increase, blood pressure levels did not decrease, and no facial flushing was observed. In both the post-MTS and control groups, 6-keto-PGF1α levels increased markedly after mesenteric traction and blood pressure decreased significantly. The post-MTS group exhibited a faster decreasing trend in 6-keto-PGF1α levels and quick restore of the mean blood pressure, and the use of vasopressors and phenylephrine were lower than that in the control group.

Conclusions

Even therapeutic administration of flurbiprofen axetil after the onset of MTS has also effects on MTS by suppressing prostacyclin production.

Trial registration

Clinical trial number: UMIN000009111. (Registered 14 October 2012)

Endothelial cells are intrinsically defective in xenophagy of Streptococcus pyogenes

Group A Streptococcus (GAS) is deleterious pathogenic bacteria whose interaction with blood vessels leads to life-threatening bacteremia. Although xenophagy, a special form of autophagy, eliminates invading GAS in epithelial cells, we found that GAS could survive and multiply in endothelial cells. Endothelial cells were competent in starvation-induced autophagy, but failed to form double-membrane structures surrounding GAS, an essential step in xenophagy. This deficiency stemmed from reduced recruitment of ubiquitin and several core autophagy proteins in endothelial cells, as demonstrated by the fact that it could be rescued by exogenous coating of GAS with ubiquitin. The defect was associated with reduced NO-mediated ubiquitin signaling. Therefore, we propose that the lack of efficient clearance of GAS in endothelial cells is caused by their intrinsic inability to target GAS with ubiquitin to promote autophagosome biogenesis for xenophagy.

BK-UM in patients with recurrent ovarian cancer or peritoneal cancer: a first-in-human phase-I study

Background

BK-UM (CRM197) is a mutant form of diphtheria toxin and a specific inhibitor of heparin-binding epidermal growth factor-like growth factor (HB-EGF). We assessed the safety, pharmacokinetics, recommended dose, and efficacy of BK-UM in patients with recurrent ovarian cancer (OC) or peritoneal cancer (PC), and measured HB-EGF levels in serum and abdominal fluid after BK-UM administration.

Methods

Eleven patients with advanced or recurrent OC or PC were enrolled and treated with BK-UM via the intraperitoneal route. The dose was escalated (1.0, 2.0, 3.3, and 5.0 mg/m²) using a 3 + 3 design.

Results

Eight of 11 patients completed treatment. No dose-limiting toxicity (DLT) was experienced at dose levels 1 (1.0 mg/m²) and 2 (2.0 mg/m²). Grade 3 transient hypotension as an adverse event (defined as a DLT in the present study) was observed in two of four patients at dose level 3 (3.3 mg/m²). Treatment with BK-UM was associated with decreases in HB-EGF levels in serum and abdominal fluid in seven of 11 patients and five of eight patients, respectively. Clinical outcomes included a partial response in one patient, stable disease in five patients, and progressive disease in five patients.

Conclusions

BK-UM was well tolerated at doses of 1.0 and 2.0 mg/m², with evidence for clinical efficacy in patients with recurrent OC or PC. A dose of 2.0 mg/m² BK-UM is recommended for subsequent clinical trials.

Trial registration

This trial was prospectively performed as an investigator-initiated clinical trial. The trial numbers are UMIN000001002 and UMIN000001001, with registration dates of 1/30/2008 and 2/4/2008, respectively. UMIN000001001 was registered as a trial for the continuous administration of BK-UM after UMIN000001002.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3071-5) contains supplementary material, which is available to authorized users.

ErbB1 and ErbB4 generate opposing signals regulating mesenchymal cell proliferation during valvulogenesis

HB-EGF plays an indispensable role in suppression of cell proliferation during mouse valvulogenesis. However, ligands of the EGF receptor (EGFR/ErbB1), including HB-EGF, are generally considered as growth-promoting factors as shown in cancers. HB-EGF binds to and activates ErbB1 and ErbB4. We investigated the role of ErbB receptors in valvulogenesis in vivo using ErbB1- and ErbB4-deficient mice, and an ex vivo model of endocardial cushion explants. We show that HB-EGF suppresses valve mesenchymal cell proliferation through a heterodimer of ErbB1 and ErbB4, and an ErbB1 ligand(s) promotes cell proliferation through a homodimer of ErbB1. Moreover, a rescue experiment with cleavable or uncleavable isoforms of ErbB4 in ERBB4 null cells indicates that the cleavable JM-a-type, but not the uncleavable JM-b-type, of ErbB4 rescues the defect of the null cells. These data suggest that the cytoplasmic intracellular domain of ErbB4, rather than the membrane-anchored tyrosine kinase, achieves this suppression. Our study demonstrates that opposing signals generated by different ErbB dimer combinations function in the same cardiac cushion mesenchymal cells for proper cardiac valve formation.

Autophagosome-lysosome fusion in neurons requires INPP5E, a protein associated with Joubert syndrome

Autophagy is a multistep membrane traffic pathway. In contrast to autophagosome formation, the mechanisms underlying autophagosome-lysosome fusion remain largely unknown. Here, we describe a novel autophagy regulator, inositol polyphosphate-5-phosphatase E (INPP5E), involved in autophagosome-lysosome fusion process. In neuronal cells, INPP5E knockdown strongly inhibited autophagy by impairing the fusion step. A fraction of INPP5E is localized to lysosomes, and its membrane anchoring and enzymatic activity are necessary for autophagy. INPP5E decreases lysosomal phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2), one of the substrates of the phosphatase, that counteracts cortactin-mediated actin filament stabilization on lysosomes. Lysosomes require actin filaments on their surface for fusing with autophagosomes. INPP5E is one of the genes responsible for Joubert syndrome, a rare brain abnormality, and mutations found in patients with this disease caused defects in autophagy. Taken together, our data reveal a novel role of phosphoinositide on lysosomes and an association between autophagy and neuronal disease.

Characterization of a Novel Anti-Human HB-EGF Monoclonal Antibody Applicable for Paraffin-Embedded Tissues and Diagnosis of HB-EGF-Related Cancers

Heparin-binding EGF-like growth factor (HB-EGF) is a member of the EGF family of growth factors that bind to and activate the EGF receptor (EGFR/ErbB1) and ErbB4. HB-EGF plays pivotal roles in pathophysiological processes, including cancer. Thus, monoclonal antibodies (mAbs) for HB-EGF detection could be an important tool in the therapeutic diagnosis of HB-EGF-related cancers and other diseases. However, few mAbs, especially those applicable for immunohistochemistry (IHC), have been established to date. In this study, we generated a clone of hybridoma-derived mAb 2-108 by immunizing mice with recombinant human HB-EGF protein expressed by human cells. The mAb 2-108 specifically bound to human HB-EGF but not to mouse HB-EGF and was successful in immunoblotting, even under reducing conditions, immunoprecipitation, and immunofluorescence for unfixed as well as paraformaldehyde-fixed cells. Notably, this mAb was effective in IHC of paraffin-embedded tumor specimens. Epitope mapping analysis showed that mAb 2-108 recognized the N-terminal prodomain in HB-EGF. These results indicate that this new anti-HB-EGF mAb 2-108 would be useful in the diagnosis of HB-EGF-related cancers and would be a strong tool in both basic and clinical research on HB-EGF.

Characterization of Chitosan Nanofiber Sheets for Antifungal Application

Chitosan produced by the deacetylation of chitin is a cationic polymer with antimicrobial properties. In this study, we demonstrate the improvement of chitosan properties by nanofibrillation. Nanofiber sheets were prepared from nanofibrillated chitosan under neutral conditions. The Young's modulus and tensile strength of the chitosan NF sheets were higher than those of the chitosan sheets prepared from dissolving chitosan in acetic acid. The chitosan NF sheets showed strong mycelial growth inhibition against dermatophytes Microsporum and Trichophyton. Moreover, the chitosan NF sheets exhibited resistance to degradation by the fungi, suggesting potentials long-lasting usage. In addition, surface-deacetylated chitin nanofiber (SDCNF) sheets were prepared. The SDCNF sheet had a high Young's modulus and tensile strength and showed antifungal activity to dermatophytes. These data indicate that nanofibrillation improved the properties of chitosan. Thus, chitosan NF and SDCNF sheets are useful candidates for antimicrobial materials.

Eosinophil-mediated signalling attenuates inflammatory responses in experimental colitis

OBJECTIVE

Eosinophils reside in the colonic mucosa and increase significantly during disease. Although a number of studies have suggested that eosinophils contribute to the pathogenesis of GI inflammation, the expanding scope of eosinophil-mediated activities indicate that they also regulate local immune responses and modulate tissue inflammation. We sought to define the impact of eosinophils that respond to acute phases of colitis in mice.

DESIGN

Acute colitis was induced in mice by administration of dextran sulfate sodium, 2,4,6-trinitrobenzenesulfonic acid or oxazolone to C57BL/6J (control) or eosinophil deficient (PHIL) mice. Eosinophils were also depleted from mice using antibodies against interleukin (IL)-5 or by grafting bone marrow from PHIL mice into control mice. Colon tissues were collected and analysed by immunohistochemistry, flow cytometry and reverse transcription PCR; lipids were analysed by mass spectroscopy.

RESULTS

Eosinophil-deficient mice developed significantly more severe colitis, and their colon tissues contained a greater number of neutrophils, than controls. This compensatory increase in neutrophils was accompanied by increased levels of the chemokines CXCL1 and CXCL2, which attract neutrophils. Lipidomic analyses of colonic tissue from eosinophil-deficient mice identified a deficiency in the docosahexaenoic acid-derived anti-inflammatory mediator 10, 17- dihydroxydocosahexaenoic acid (diHDoHE), namely protectin D1 (PD1). Administration of an exogenous PD1-isomer (10S, 17S-DiHDoHE) reduced the severity of colitis in eosinophil-deficient mice. The PD1-isomer also attenuated neutrophil infiltration and reduced levels of tumour necrosis factor-α, IL-1β, IL-6 and inducible NO-synthase in colons of mice. Finally, in vitro assays identified a direct inhibitory effect of PD1-isomer on neutrophil transepithelial migration.

CONCLUSIONS

Eosinophils exert a protective effect in acute mouse colitis, via production of anti-inflammatory lipid mediators.

Identification of diphtheria toxin R domain mutants with enhanced inhibitory activity against HB-EGF

Heparin-binding epidermal growth factor-like growth factor (HB-EGF), a ligand of EGF receptor, is involved in the growth and malignant progression of cancers. Cross-reacting material 197, CRM197, a non-toxic mutant of diphtheria toxin (DT), specifically binds to the EGF-like domain of HB-EGF and inhibits its mitogenic activity, thus CRM197 is currently under evaluation in clinical trials for cancer therapy. To develop more potent DT mutants than CRM197, we screened various mutant proteins of R domain of DT, the binding site for HB-EGF. A variety of R-domain mutant proteins fused with maltose-binding protein were produced and their inhibitory activity was evaluated in vitro. We found four R domain mutants that showed much higher inhibitory activity against HB-EGF than wild-type (WT) R domain. These R domain mutants suppressed HB-EGF-dependent cell proliferation more effectively than WT R domain. Surface plasmon resonance revealed their higher affinity to HB-EGF than WT R domain. CRM197(R460H) carrying the newly identified mutation showed increased cell proliferation inhibitory activity and affinity to HB-EGF. These results suggest that CRM197(R460H) or other recombinant proteins carrying newly identified mutation(s) in the R domain are potential therapeutics targeting HB-EGF.

Immunomodulation with eicosapentaenoic acid supports the treatment of autoimmune small-vessel vasculitis

Small-vessel vasculitis is a life-threatening autoimmune disease that is frequently associated with anti-neutrophil cytoplasmic antibodies (ANCAs). Conventional immunotherapy including steroids and cyclophosphamide can cause serious adverse events, limiting the efficacy and safety of treatment. Eicosapentaenoic acid (EPA), a key component of fish oil, is an omega-3 polyunsaturated fatty acid widely known to be cardioprotective and beneficial for vascular function. We report two elderly patients with systemic ANCA-associated vasculitis (AAV) in whom the administration of EPA in concert with steroids safely induced and maintained remission, without the use of additioal immunosuppressants. To explore the mechanisms by which EPA enhances the treatment of AAV, we employed SCG/Kj mice as a spontaneous murine model of AAV. Dietary enrichment with EPA significantly delayed the onset of crescentic glomerulonephritis and prolonged the overall survival. EPA-derived anti-inflammatory lipid mediators and their precursors were present in the kidney, plasma, spleen, and lungs in the EPA-treated mice. Furthermore, a decrease in ANCA production and CD4/CD8-double negative T cells, and an increase in Foxp3(+) regulatory T cells in the lymph nodes of the kidney were observed in the EPA-treated mice. These clinical and experimental observations suggest that EPA can safely support and augment conventional therapy for treating autoimmune small-vessel vasculitis.

Eicosapentaenoic acid is converted via ω-3 epoxygenation to the anti-inflammatory metabolite 12-hydroxy-17,18-epoxyeicosatetraenoic acid

Eicosapentaenoic acid (EPA) has beneficial effects in many inflammatory disorders. In this study, dietary EPA was converted to 17,18-epoxyeicosatetraenoic acid (17,18-EpETE) by ω-3 epoxygenation in the mouse peritoneal cavity. Mediator lipidomics revealed a series of novel oxygenated metabolites of 17,18-EpETE, and one of the major metabolites, 12-hydroxy-17,18-epoxyeicosatetraenoic acid (12-OH-17,18-EpETE), displayed a potent anti-inflammatory action by limiting neutrophil infiltration in murine zymosan-induced peritonitis. 12-OH-17,18-EpETE inhibited leukotriene B4-induced neutrophil chemotaxis and polarization in vitro in a low nanomolar range (EC50 0.6 nM). The complete structures of two natural isomers were assigned as 12S-OH-17R,18S-EpETE and 12S-OH-17S,18R-EpETE, using chemically synthesized stereoisomers. These natural isomers displayed potent anti-inflammatory action, whereas the unnatural stereoisomers were essentially devoid of activity. These results demonstrate that 17,18-EpETE derived from dietary EPA is converted to a potent bioactive metabolite 12-OH-17,18-EpETE, which may generate an endogenous anti-inflammatory metabolic pathway.

Omega-3 polyunsaturated Fatty acids suppress the cystic lesion formation of peritoneal endometriosis in transgenic mouse models

Omega-3 polyunsaturated fatty acids (omega-3 PUFAs) play a role in controlling pathological inflammatory reactions. Endometriosis is characterized by the presence of endometrial tissue on the peritoneum and an exaggerated inflammatory environment around ectopic tissues. Here peritoneal endometriosis was reproduced using a mouse model in which murine endometrial fragments were inoculated into the peritoneal cavity of mice. Fat-1 mice, in which omega-6 can be converted to omega-3 PUFAs, or wild type mice, in which it cannot, were used for the endometriosis model to address the actions of omega-3 PUFAs on the development of endometriotic lesions. The number and weight of cystic endometriotic lesions in fat-1 mice two weeks after inoculation were significantly less than half to those of controls. Mediator lipidomics revealed that cystic endometriotic lesions and peritoneal fluids were abundant in 12/15-hydroxyeicosapentaenoic acid (12/15-HEPE), derived from eicosapentaenoic acid (EPA), and their amount in fat-1 mice was significantly larger than that in controls. 12/15-Lipoxygenase (12/15-LOX)-knockout (KO) and control mice with or without EPA administration were assessed for the endometriosis model. EPA administration decreased the number of lesions in controls but not in 12/15-LOX-KO mice. The peritoneal fluids in EPA-fed 12/15-LOX-KO mice contained reduced levels of EPA metabolites such as 12/15-HEPE and EPA-derived resolvin E3 even after EPA administration. cDNA microarrays of endometriotic lesions revealed that Interleukin-6 (IL-6) expression in fat-1 mice was significantly lower than that in controls. These results suggest that both endogenous and exogenous EPA-derived PUFAs protect against the development of endometriosis through their anti-inflammatory effects and, in particular, the 12/15-LOX-pathway products of EPA may be key mediators to suppress endometriosis.

Metastasis suppressor tetraspanin CD82/KAI1 regulates ubiquitylation of epidermal growth factor receptor

Ligand-induced ubiquitylation of EGF receptor (EGFR) is an important regulatory mechanism that controls endocytic trafficking of the receptor and its signaling potential. Here we report that tetraspanin CD82/KAI1 specifically suppresses ubiquitylation of EGFR after stimulation with heparin-binding EGF or amphiregulin and alters the rate of recruitment of the activated receptor to EEA1-positive endosomes. The suppressive effect of CD82 is dependent on the heparin-binding domain of the ligand. Deletion of the C-terminal cytoplasmic domain of CD82 (CD82ΔC mutant) inhibits endocytic trafficking of the tetraspanin and compromises its activity toward heparin-binding EGF-activated EGFR. Reduced ubiquitylation of EGFR is accompanied by PKC-dependent increase in serine phosphorylation of c-Cbl in cells expressing elevated levels of CD82. Furthermore, phosphorylation of threonine 654 (PKC phosphorylation site) in the juxtamembrane domain of the receptor is considerably increased in CD82-expressing cells. These results describe previously unsuspected links between tetraspanin proteins and ubiquitylation of their molecular partners (e.g., EGFR). Our data identify CD82 as a new regulator of c-Cbl, which discriminatively controls the activity of this E3 ubiquitin ligase toward heparin-binding ligand-EGFR pairs. Taken together, these observations provide an important new insight into the modulatory role of CD82 in endocytic trafficking of EGF receptor.

Conditional loss of heparin-binding EGF-like growth factor results in enhanced liver fibrosis after bile duct ligation in mice

Our aims were to evaluate the involvement of heparin-binding EGF-like growth factor (HB-EGF) in liver fibrogenesis of humans and mice and to elucidate the effect of HB-EGF deficiency on cholestatic liver fibrosis using conditional HB-EGF knockout (KO) mice. We first demonstrated that gene expression of HB-EGF had a positive significant correlation with that of collagen in human fibrotic livers, and was increased in bile duct ligation (BDL)-induced fibrotic livers in mouse. We then generated conditional HB-EGF knockout (KO) mice using the interferon inducible Mx-1 promoter driven Cre recombinase transgene and wild type (WT) and KO mice were subjected to BDL. After BDL, KO mice exhibited enhanced liver fibrosis with increased expression of collagen, compared with WT mice. Finally, we used mouse hepatic stellate cells (HSCs) to examine the role of HB-EGF in the activation of these cells and showed that HB-EGF antagonized TGF-β-induced gene expression of collagen in mouse primary HSCs. Interestingly, HB-EGF did not prevent the TGF-β-induced nuclear accumulation of Smad3, but did lead to stabilization of the Smad transcriptional co-repressor TG-interacting factor. In conclusion, our data suggest a possible protective role of HB-EGF in cholestatic liver fibrosis.

Conditional knockout of heparin-binding epidermal growth factor-like growth factor in the liver accelerates carbon tetrachloride-induced liver injury in mice

AIM

  We previously demonstrated that heparin-binding epidermal growth factor-like growth factor (HB-EGF) is induced in response to several liver injuries. Because the HB-EGF knockout (KO) mice die in utero or immediately after birth due to cardiac defects, the loss of function study in vivo is limited. Here, we generated liver-specific HB-EGF conditional knockout mice using the interferon-inducible Mx-1 promoter driven cre recombinase transgene and investigated its role during acute liver injury.

METHODS

  We induced acute liver injury by a single i.p. injection of carbon tetrachloride (CCl4 ) in HB-EGF KO mice and wild-type mice and liver damage was assessed by biochemical and immunohistochemical analysis. We also used AML12 mouse hepatocyte cell lines to examine the molecular mechanism of HB-EGF-dependent anti-apoptosis and wound-healing process of the liver in vitro.

RESULTS

  HB-EGF KO mice exhibited a significant increase of alanine aminotransferase level and also showed a significant increase in the number of apoptotic hepatocytes assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling staining at 24 h after CCl4 injection. We also demonstrated that HB-EGF treatment inhibited tumor necrosis factor-α-induced apoptosis of AML12 mouse hepatocytes and promoted the wound-healing response of these cells.

CONCLUSION

  This study showed that HB-EGF plays a protective role during acute liver injury.

The lipid mediator protectin D1 inhibits influenza virus replication and improves severe influenza

Influenza A viruses are a major cause of mortality. Given the potential for future lethal pandemics, effective drugs are needed for the treatment of severe influenza such as that caused by H5N1 viruses. Using mediator lipidomics and bioactive lipid screen, we report that the omega-3 polyunsaturated fatty acid (PUFA)-derived lipid mediator protectin D1 (PD1) markedly attenuated influenza virus replication via RNA export machinery. Production of PD1 was suppressed during severe influenza and PD1 levels inversely correlated with the pathogenicity of H5N1 viruses. Suppression of PD1 was genetically mapped to 12/15-lipoxygenase activity. Importantly, PD1 treatment improved the survival and pathology of severe influenza in mice, even under conditions where known antiviral drugs fail to protect from death. These results identify the endogenous lipid mediator PD1 as an innate suppressor of influenza virus replication that protects against lethal influenza virus infection.