Two autopsied gastric cancer cases of rare drug-induced pneumonia associated with nivolumab plus S-1 and oxaliplatin: a case report.

Background: Drug-induced pneumonia, especially immune-related adverse events, can sometimes be fatal, and it is crucial to seize the signs for early treatment. A clinical trial (ATTRACTION-4) reported no cases of grade 4 or 5 pneumonia or interstitial lung disease associated with nivolumab plus S-1 and oxaliplatin. However, we encountered two cases of fatal pneumonia induced by this regimen. Case Description: The two patients were in their 70s, male and diagnosed gastric cancer with peritoneal dissemination. The patient of case 1 underwent surgery and adjuvant chemotherapy nine years before. The patient of case 2 was diagnosed unresectable 6 months before and chemo naïve. Both patients received nivolumab plus S-1 and oxaliplatin for the dissemination. The onset of both cases occurred after the fifth dose of the regimen, and the responses to corticosteroids were transient and limited. Computed tomography showed bilateral consolidation and ground-glass opacities, seemingly similar to an organizing pneumonia pattern. Acute and organizing stages of diffuse alveolar damage were detected histopathologically. Despite showing notable antitumor effects, both patients had indications of interstitial pneumonitis before admission, such as elevation of C-reactive protein (CRP) and Krebs von den Lungen-6 (KL-6) levels and slight lung opacity or respiratory symptoms approximately 10 days before admission. Conclusions: Patients undergoing nivolumab plus S-1 and oxaliplatin should be closely followed up with imaging, evaluation of symptom including oxygen saturation, and serological marker analysis such as lactate dehydrogenase, CRP, and KL-6. Early detection of pneumonia leads to adequate cessation of chemotherapy and early treatment, and this can prevent severe adverse events.

The fine-needle aspiration cytology and clinical findings of Kikuchi-Fujimoto disease in pediatric patients: a retrospective clinical study.

BACKGROUND: Histological evaluation of lymph node is crucial for the definitive diagnosis of Kikuchi-Fujimoto disease (KFD). However, lymph node biopsy under local anesthesia is often difficult in pediatric patients. OBJECTIVES: We evaluated cytological findings for pediatric patients with prolonged cervical lymphadenitis clinically suggestive of KFD and investigated the clinical characteristics of patients diagnosed with KFD by fine-needle aspiration cytology (FNAC). METHODS: This retrospective clinical study included 58 Japanese pediatric patients with cervical lymphadenitis who underwent FNAC. RESULTS: Cytological diagnosis was KFD for 22 and suspicion of KFD for 11 patients. The remaining 25 patients were diagnosed with non-specific lymphadenitis (NSL). Tenderness was independently associated with a higher frequency of both KFD in narrow and broad senses, compared with NSL (p = .009; p = .038). The percentage of patients who underwent FNAC within 28 days from symptom onset tended to be higher among patients with KFD in a narrow sense than those with NSL (p = .052). CONCLUSION: This study indicated that the period from symptom onset to FNAC (<28 days) and the symptom of tenderness were associated with the cytological diagnosis of KFD.

Supraglottic subepithelial benign mass lesions: Focus on clinical features of sialolipoma-like lesion.

OBJECTIVES: Sialolipoma has been classified as a benign soft tissue lesion in the 2017 World Health Organization classification of head and neck tumors. To our knowledge, only one case of laryngeal sialolipoma has been reported in the English literature. We conducted a retrospective study to identify clinical characteristics of supraglottic sialolipoma-like lesion and differentiate it from other supraglottic subepithelial masses. METHODS: Medical records of 16 patients with supraglottic subepithelial benign mass lesions who underwent histological evaluation between 2003 and 2019 were retrospectively analyzed. Sialolipoma-like lesion was defined as a local finding of a well-circumscribed gross mass with pathological presence of salivary gland-like parenchymal lobules with evenly interspersed adipose tissue. RESULTS: Eight patients showed histological positivity for sialolipoma-like lesion, 3 for amyloidosis, 2 for hemangioma, and 1 each for cyst, lymphoid hyperplasia, and chondrometaplasia. Sialolipoma-like lesion tended to be predominant among men; those affected had a mean age of 52.8 (range, 39-74) years. By contrast, among patients with amyloidosis, the ratio of men to women was 1:2 (100% vs. 33%; p = 0.055). Fiberscopic examination of all patients with sialolipoma-like lesions identified well-circumscribed, yellowish masses, closely resembling local amyloidosis findings. Sialolipoma-like lesion was associated with a significantly higher body-mass index (BMI; 27.4 ± 2.8 kg/m2) than amyloidosis (21.6 ± 1.4 kg/m2; p = 0.014). The transoral approach was used for lesion resection in all patients with sialolipoma-like lesion. No patient experienced postoperative recurrence. CONCLUSION: Laryngeal sialolipoma-like lesion might be more prevalent than was previously reported, and histological examination is important to differentiate it from amyloidosis. Supraglottic sialolipoma-like lesion must be differentially diagnosed in patients with high BMI presenting with well-circumscribed, yellowish supraglottic masses.

Isolated cortical tuber in an infant with genetically confirmed tuberous sclerosis complex 1 presenting with symptomatic West syndrome.

Tuberous sclerosis complex (TSC) is an autosomal dominant hereditary disorder caused by mutations in either TSC1 on chromosome 16 or TSC2 on chromosome 9, clinically characterized mainly by facial angiofibroma, epilepsy, and intellectual disability. Cortical dysplasias, subependymal nodules, and subependymal giant cell astrocytoma are characteristic central nervous system lesions among 11 major features in the current clinical diagnostic criteria for TSC. We encountered an unusual case of genetically confirmed TSC1 presenting with symptomatic West syndrome due to an isolated cortical dysplasia in the left occipital lobe of a six-month-old male infant who did not meet the clinical diagnostic criteria for TSC. The patient underwent left occipital lesionectomy at age 11 months and has been seizure-free for nearly six years since then. Histological examination of the resection specimen revealed cortical neuronal dyslamination with abundant dysmorphic neurons and ballooned cells, consistent with focal cortical dysplasia (FCD) type IIb. However, the lesion was also accompanied by unusual features, including marked calcifications, dense fibrillary gliosis containing abundant Rosenthal fibers, CD34-positive glial cells with abundant long processes confined to the dysplastic cortex, and multiple nodular lesions occupying the underlying white matter, consisting exclusively of ballooned cell and/or balloon-like astrocytes with focal calcifications. Genetic testing for TSC1 and TSC2 using the patient's peripheral blood revealed a germline heterozygous mutation in exon 7 (NM_000368.5: c.526dupT, p.Tyr176fs) in TSC1. Isolated FCD with unusual features such as calcification, dense fibrillary gliosis, Rosenthal fibers and/or subependymal nodule-like lesions in the white matter may indicate the possibility of a cortical tuber even without a clinical diagnosis of TSC. Identification of such histopathological findings has significant implications for early and accurate diagnosis and treatment of TSC, and is likely to serve as an important supplementary feature for the current clinical diagnostic criteria for TSC.

ALK rearranged renal cell carcinoma (ALK-RCC): a multi-institutional study of twelve cases with identification of novel partner genes CLIP1, KIF5B and KIAA1217.

ALK rearranged renal cell carcinoma (ALK-RCC) has recently been included in 2016 WHO classification as a provisional entity. In this study, we describe 12 ALK-RCCs from 8 institutions, with detailed clinical, pathological, immunohistochemical (IHC), fluorescence in situ hybridization (FISH), and next generation sequencing (NGS) analyses. Patients' age ranged from 25 to 68 years (mean, 46.3 years). Seven patients were females and five were males (M:F = 1:1.4). Tumor size ranged from 17 to 70 mm (mean 31.5, median 25 mm). The pTNM stage included: pT1a (n = 7), pT1b (n = 1), and pT3a (n = 4). Follow-up was available for 9/12 patients (range: 2 to 153 months; mean 37.6 months); 8 patients were alive without disease and one was alive with distant metastases. The tumors demonstrated heterogeneous, 'difficult to classify' morphology in 10/12 cases, typically showing diverse architectural and cellular morphologies, including papillary, tubular, tubulocystic, solid, sarcomatoid (spindle cell), rhabdoid, signet-ring cell, and intracytoplasmic vacuoles, often set in a mucinous background. Of the remaining two tumors, one showed morphology resembling mucinous tubular and spindle cell renal cell carcinoma (MTSC RCC-like) and one was indistinguishable from metanephric adenoma. One additional case also showed a focal metanephric adenoma-like area, in an otherwise heterogeneous tumor. By IHC, all tumors were diffusely positive for ALK and PAX8. In both cases with metanephric adenoma-like features, WT1 and ALK were coexpressed. ALK rearrangement was identified in 9/11 tumors by FISH. ALK fusion partners were identified by NGS in all 12 cases, including the previously reported: STRN (n = 3), TPM3 (n = 3), EML4 (n = 2), and PLEKHA7 (n = 1), and also three novel fusion partners: CLIP1 (n = 1), KIF5B (n = 1), and KIAA1217 (n = 1). ALK-RCC represents a genetically distinct entity showing a heterogeneous histomorphology, expanded herein to include unreported metanephric adenoma-like and MTSC RCC-like variants. We advocate a routine ALK IHC screening for "unclassifiable RCCs" with heterogeneous features.

Juvenile Granulosa Cell Tumor with an Unusual Clinical Course: A Late-onset and Late Recurrent Case.

Juvenile granulosa cell tumors (JGCTs) are rare ovarian tumors with overall good prognoses. They differ from adult granulosa cell tumors (AGCTs), which are well known for late recurrence. Most JGCTs (～97%) occur in individuals <30 years old. We report a recurrent JGCT in a 40-year-old woman 5 years after initial presentation. The histological appearance and lack of 402C>G missense point mutation of FOXL2 gene (characteristic of AGCT but absent in JGCT) allowed differentiation from AGCT. This is the first comprehensive report of JGCT with late recurrence. Although rare, late recurrence of JGCT can occur; long-term surveillance is suggested.

The efficacy of OK-432 sclerotherapy on thyroglossal duct cyst and the influence on a subsequent surgical procedure.

Background: Although there are studies regarding the efficacy of OK-432 sclerotherapy on thyroglossal duct cyst (TDC), its effects on surgical procedure following this therapy have not been properly described. Objectives: The present study aimed to delineate the prognostic factors of OK-432 sclerotherapy in patients with TDC and investigate its influence on subsequent surgical procedure and the histological characteristics in patients with poor response to OK-432 sclerotherapy. Material and methods: We conducted a retrospective analysis of the medical records of 20 TDC patients treated with OK-432 sclerotherapy. Results: Of the 20 patients, OK-432 sclerotherapy was effective in 5 patients (25.0%). OK-432 showed a lower effective rate in multilocular cysts (9.1%) than in unilocular cysts (44.4%), although not significantly. Five cases were treated with surgery following OK-432 sclerotherapy. There was no significant difference in the operating time and the amount of bleeding between patients with and without OK-432 sclerotherapy. From the results of the histological examination of the cyst wall, two cases had stratified squamous epithelium and two cases showed the absence of lymphocyte infiltration. Conclusion and significance: OK-432 sclerotherapy is an acceptable initial treatment for TDC, especially in unilocular cysts, because of lack of influence on surgical procedure.

A "Back Light System" for Identification of Sites for Endoscopic Ultrasound-Guided Fine-Needle Aspiration in Solid Pancreatic Masses: A Prospective, Randomized Study with a Crossover Design.

BACKGROUND/AIMS: We applied a back light system (BLS) with a magnifying glass to improve the ability to assess the adequacy of specimen sampling using endosonography. We conducted this study to evaluate the efficacy of the BLS in sampling of specimens by endoscopic ultrasound-guided fine needle aspiration of solid pancreatic masses. METHODS: This was a prospective, randomized, crossover, single-center clinical trial. An endosonographer evaluated adequacy on gross visual inspection and identified whitish specimen sampling sites with and without the BLS according to a randomization sequence in the first and second passes with a 25-G needle. On cytological evaluation, the presence of well-defined pancreatic ductal epithelium was evaluated by a cytopathologist who was blinded to any clinical information. RESULTS: A total of 80 consecutive patients were eligible during the study period. Adequacy was observed for 52 specimens (65%) with the BLS and 54 (68%) without the BLS (p=0.88). In assessment of specimen adequacy on gross examination, only fair agreement was observed both with and without BLS (kappa score 0.40 and 0.29, respectively). CONCLUSION: The BLS did not influence the ability to identify specimen sampling sites or reliable assessment of specimen site adequacy using gross visual inspection.

The relationship between the PD-L1 expression of surgically resected and fine-needle aspiration specimens for patients with pancreatic cancer.

BACKGROUND: Recently, therapeutic antibodies against programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) have shown promising clinical results for several solid tumors, including pancreatic cancer. In this study, we evaluated the relationship between the PD-L1 expression of surgical resected and fine-needle aspiration (FNA) specimens for patients with pancreatic cancer. METHODS: Of 121 patients who underwent endoscopic ultrasound-guided (EUS)-FNA before surgery for pancreatic cancer in an academic center, the 94 (78%) with adequate FNA specimens for a histological evaluation were retrospectively analyzed. All the patients had undergone upfront surgery without any chemotherapy or radiotherapy. We performed immunohistochemistry (IHC) staining to investigate the PD-L1 expression in both resected and FNA specimens. The positive-stained cells were counted, and their percentage was used for the investigation. RESULTS: Of the 94 patients, 16 (17%) and 11 (10%) were defined as positive on resected cancer specimens using cutoff points of 5% and 10% positively stained cancer cell counts, respectively. The concordance rates for the positive frequency of PD-L1 expression between resected and FNA specimens were 44% (7/16) and 55% (6/11) when the positivity was set to ≥ 5% and ≥ 10%, respectively. The concordance rates for the negative frequency of PD-L1 expression between two specimens were 97% (76/78) and 99% (82/83) when the positivity was set to ≥ 5% and ≥ 10%, respectively. CONCLUSIONS: Approximately, half of the patients with PD-L1 expression positive and almost all the patients with PD-L1 expression negative could be diagnosed on FNA specimens.

Spred2-deficiecy Protects Mice from Polymicrobial Septic Peritonitis by Enhancing Inflammation and Bacterial Clearance.

Sepsis is an infection-induced systemic inflammatory syndrome and a major cause of death for critically ill patients. Here, we examined whether the absence of Sprouty-related EVH1-domain-containing protein 2 (Spred2), a negative regulator of the Ras/Raf/ERK/MAPK pathway, influences host defense against polymicrobial sepsis (PMS) induced by cecal ligation and puncture (CLP). Compared to wild-type mice, Spred2-/- mice exhibited higher survival rates with increased level of leukocyte infiltration and local chemokine production and reduced plasma and peritoneal bacterial loads after CLP. The MEK inhibitor U0126 significantly reduced LPS-induced chemokine production by Spred2-/- resident macrophages in vitro, and decreased CLP-induced leukocyte infiltration in vivo. Spred2-/- resident macrophages, but not neutrophils or elicited macrophages, exhibited increased phagocytic activity. Interestingly, surface expression of complement receptor 1/2 (CR1/2) was increased in Spred2-/- resident macrophages in response to lipopolysaccharide in a manner dependent on the ERK/MAPK pathway, and blocking CR1/2 in vivo resulted in reduced leukocyte infiltration and increased bacterial loads after CLP. Taken together, our results indicate that Spred2-deficiency protects mice from PMS via increased activation of the ERK/MAPK pathway and subsequent increase in innate immune responses. Thus, inhibiting Spred2 may present a novel means to prevent the development of PMS.

Molecular Subtypes of Breast Cancers from Myanmar Women: A Study of 91 Cases at Two Pathology Centers

Background: Breast cancer is the most common cancer in Myanmar women. Revealing the hormonal receptor status, human epidermal growth factor receptor 2 (HER2) and Ki-67 expression is useful for estimating patient prognosis as well as determination of treatment strategy. However, immunohistochemical features and classification of molecular subtypes in breast cancers from Myanmar remain unknown. Methods: The clinicopathological features of 91 breast cancers from Myanmar women were examined. Immunohistochemistry was performed on tissue specimens with antibodies to estrogen receptor (ER), progesterone receptor (PgR), HER2, Ki-67, cytokeratin (CK)5/6 and CK14. Immunohistochemistry-based molecular subtyping was conducted. Results: Breast cancers in Myanmar women were relatively large, high grade with frequent metastatic lymph nodes. Of the 91 patients, tumors with ER positive, PgR positive, and HER2 positive were 57.1%, 37.4%, and 28.6%, respectively. The most prevalent subtype was luminal B (HER2-) (39.6%), followed by HER2 (22.0%), triple negative (TN)-basal-like (12.1%), luminal A (11.0%), TN-null (8.8%) and luminal B (HER2+) (6.6%). The mean Ki-67 expression of 91 cases was 33.9% (33.9% ± 19.2%) and the median was 28% (range; 4%-90%). The mean Ki-67 expression of luminal A, luminal B, HER2 and TN-basal-like/ null was 7%, 30%, 40%, and 57%/43%, respectively. A higher Ki-67 expression significantly correlated with a higher grade, larger size and higher stage of malignancy. Conclusions: We, for the first time, investigated the histopathological features of breast cancers from Myanmar women. Myanmar breast cancers appeared to be aggressive in nature, as evidenced by high frequency of poor-prognosis subtypes with high level of Ki-67 expression.

Low prevalence of human mammary tumor virus (HMTV) in breast cancer patients from Myanmar.

BACKGROUND: Human mammary tumor virus (HMTV) is 90-95% homologous to mouse mammary tumor virus (MMTV), one of the causal agents of murine mammary tumors. HMTV (MMTV-like) sequences were reported to be present in human breast cancers from several populations with a prevalence range of 0-78%; however, the prevalence of HMTV in breast cancers from Myanmar remains unknown. METHODS: Fifty-eight breast cancer samples from Myanmar women were examined in this study. DNA was isolated from formalin-fixed paraffin-embedded specimens, and HMTV envelope sequences were detected by semi-nested PCR. The sequence of the PCR products was also confirmed. RESULTS: Only 1.7% (1 of 58) of the breast cancers were positive for HMTV, and the sequence of PCR products was 98.9% identical to the reference HMTV sequence (GenBank accession No. AF243039). The tumor with HMTV was grade III invasive ductal carcinoma, 7.0 cm in size with lymph node metastasis (T3, N1, M0). CONCLUSIONS: We, for the first time, investigated the presence of HMTV in Myanmar breast cancer patients. In accordance with other Asian studies, the prevalence of HMTV in Myanmar was quite low, supporting the hypothesis that Asian breast cancers have different etiologies than in Western countries, where HMTV is more prevalent.

A Novel Role of Spred2 in the Colonic Epithelial Cell Homeostasis and Inflammation.

Rapid and adequate mucosal healing is important for a remission of ulcerative colitis (UC) patients. Here, we examined whether Spred2, a member of the Sprouty-related EVH1-domain-containing proteins that inhibit the Ras/Raf/ERK pathway, plays a role in colonic mucosal homeostasis and inflammation by using Spred2 knockout (KO) mice. We first detected increased epithelial cell proliferation and cadherin 1 expression in the colon of naïve Spred2 KO mice compared to wild-type mice. Interestingly, Spred2 KO mice were resistant to dextran sulfate sodium (DSS)-induced acute colitis as indicated by lower levels of body weight loss and disease activity index. Histologically, epithelial cell injury and inflammation were milder in the colonic mucosa of Spred2 KO mice on day 3 and almost undetectable by day 8. Experiments with bone chimeric mice indicated that Spred2-deficiency in non-hematopoietic cells was responsible for the reduced sensitivity to DSS. Finally, Spred2 KO mice developed significantly fewer tumors in response to azoxymethane plus DSS. Taken together, our results demonstrate, for the first time, that Spred2 plays an important role in the regulation of colonic epithelial cell proliferation and inflammation by potentially down-regulating the activation of ERK. Thus, Spred2 may be a new therapeutic target for the treatment of UC.

C-Terminal-Deleted Prion Protein Fragment Is a Major Accumulated Component of Systemic PrP Deposits in Hereditary Prion Disease With a 2-Bp (CT) Deletion in PRNP Codon 178.

Prion protein (PrP) has 2 glycosylated sites and a glycosylphosphatidylinositol (GPI) anchor on the C-terminal. Reports on genetic prion disease with GPI anchorless PrP are very limited. In this study, we characterized the molecular alterations of mutated PrP in a 37-year-old female autopsy case with a recently identified PRNP mutation involving a 2-bp deletion in codon 178 that results in a premature stop codon mutation in codon 203. Postmortem examination revealed numerous irregularly shaped coarse PrP deposits and multicentric plaques in the brain that were mainly comprised of C-terminal deleted abnormal PrP primarily derived from the mutant allele. Additionally, abnormal PrP deposits were detected in almost all other examined organs. PrP was mainly deposited in peripheral nerves, smooth muscles, and blood vessels in non-CNS tissues. Western blot analysis after proteinase K treatment showed protease-resistant PrP (PrPres) signals with a molecular weight of 9 kDa; weak PrPres smear signals of 9 to ∼80 kDa were also noted. Gel filtration revealed that PrPres oligomers were mainly composed of the PrP fragments. In conclusion, the mutated PrP lacking that GPI anchor was truncated shortly and deposited in almost every examined organ.

Time-dependent image changes after ethanol injection into the pancreas: an experimental study using a porcine model.

BACKGROUND: Ethanol, a commonly available agent, has been used to successfully ablate cystic and solid lesions in the pancreas. The aim of this study is to investigate the effects of an ethanol injection into the porcine pancreas and observe the time-dependent image changes in the pancreatic parenchyma. METHODS: Pure ethanol was injected into the pancreatic tail using a 25-gauge EUS needle with direct ultrasound guidance under celiotomy: 1 mL and 2 mL were injected, respectively. The abdomen was closed after the injection. MRI was performed before the procedure, immediately after, and on postoperative day (POD) seven. Blood samples were taken before the procedure and on PODs one, three, five, and seven. The pigs were euthanised on POD seven. RESULTS: Immediately after the injection, linear high signal areas in the pancreatic tail on T2 and rounded speckled high signal areas on DWI images were detected in both animals, measuring 35 × 32 mm in the 1 mL injected pig and 42 × 38mm in the 2 mL injected pig. After POD seven, rounded high signal areas were noted on T2 images, measuring 22 × 18 mm and 36 × 28 mm respectively. On POD one, the 1 mL injected animal had a 53% elevation in serum amylase while the 2 mL injected animal had a 66% elevation. Histologically, cystic and necrotic changes in the parenchyma were observed, measuring 23 × 22 mm and 40 × 35 mm respectively. CONCLUSIONS: Our results, which are limited to normal pancreas, suggested that a 1 mL injection caused localised changes within the pancreas while a 2 mL injection induced more widespread changes beyond the pancreas. The effective area of ethanol was widespread immediately after injection, and then the area was reduced with cystic and necrosis changes.

Pancreatic Hepatoid Carcinoma Mimicking a Solid Pseudopapillary Neoplasm: A Challenging Case on Endoscopic Ultrasound-guided Fine-needle Aspiration.

A 59-year-old man was admitted to our hospital for treatment of a 45 mm pancreatic mass found during a medical examination. Endoscopic ultrasound-guided fine-needle aspiration cytology showed polygonal cells with pseudopapillary structures. The tumor cells were positive for nuclear/cytoplasmic ß-catenin and CD10, and negative for chromogranin A. After a tentative diagnosis of a solid pseudopapillary neoplasm, middle pancreatectomy was performed. Histologically, polygonal cells with abundant eosinophilic cytoplasm formed in the trabeculae and were immunohistochemically positive for HepPar1 and protein induced by vitamin K absence or antagonist-II. The tumor was finally diagnosed to be pancreatic hepatoid carcinoma. No recurrence occurred for 12 months, even without adjuvant chemotherapy.

Sprouty-Related Ena/Vasodilator-Stimulated Phosphoprotein Homology 1-Domain-Containing Protein-2 Critically Regulates Influenza A Virus-Induced Pneumonia.

OBJECTIVES: Influenza A virus causes acute respiratory infections that induce annual epidemics and occasional pandemics. Although a number of studies indicated that the virus-induced intracellular signaling events are important in combating influenza virus infection, the mechanism how specific molecule plays a critical role among various intracellular signaling events remains unknown. Raf/MEK/extracellular signal-regulated kinase cascade is one of the key signaling pathways during influenza virus infection, and the Sprouty-related Ena/vasodilator-stimulated phosphoprotein homology 1-domain-containing protein has recently been identified as a negative regulator of Raf-dependent extracellular signal-regulated kinase activation. Here, we examined the role of Raf/MEK/extracellular signal-regulated kinase cascade through sprouty-related Ena/vasodilator-stimulated phosphoprotein homology 1-domain-containing protein in influenza A viral infection because the expression of sprouty-related Ena/vasodilator-stimulated phosphoprotein homology 1-domain-containing protein was significantly enhanced in human influenza viral-induced pneumonia autopsy samples. DESIGN: Prospective animal trial. SETTING: Research laboratory. SUBJECTS: Wild-type and sprouty-related Ena/vasodilator-stimulated phosphoprotein homology 1-domain-containing protein-2 knockout mice inoculated with influenza A. INTERVENTIONS: Wild-type or sprouty-related Ena/vasodilator-stimulated phosphoprotein homology 1-domain-containing protein-2 knockout mice were infected by intranasal inoculation of influenza A (A/PR/8). An equal volume of phosphate-buffered saline was inoculated intranasally into mock-infected mice. MEASUREMENTS AND MAIN RESULTS: Influenza A infection of sprouty-related Ena/vasodilator-stimulated phosphoprotein homology 1-domain-containing protein-2 knockout mice led to higher mortality with greater viral load, excessive inflammation, and enhanced cytokine production than wild-type mice. Administration of MEK inhibitor, U0126, improved mortality and reduced both viral load and cytokine levels. Furthermore, bone marrow chimeras indicated that influenza A-induced lung pathology was most severe when sprouty-related Ena/vasodilator-stimulated phosphoprotein homology 1-domain-containing protein-2 expression was lacking in nonimmune cell populations. Furthermore, microarray analysis revealed knockdown of sprouty-related Ena/vasodilator-stimulated phosphoprotein homology 1-domain-containing protein-2 led to enhanced phosphatidylinositol 3-kinase signaling pathway, resulting that viral clearance was regulated by sprouty-related Ena/vasodilator-stimulated phosphoprotein homology 1-domain-containing protein-2 expression through the phosphatidylinositol 3-kinase signaling pathway in murine lung epithelial cells. CONCLUSIONS: These data support an important function of sprouty-related Ena/vasodilator-stimulated phosphoprotein homology 1-domain-containing protein-2 in controlling influenza virus-induced pneumonia and viral replication. Sprouty-related Ena/vasodilator-stimulated phosphoprotein homology 1-domain-containing protein-2 may be a novel therapeutic target for controlling the immune response against influenza influenza A virus infection.

Spred-2 deficiency exacerbates lipopolysaccharide-induced acute lung inflammation in mice.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is a severe and life-threatening acute lung injury (ALI) that is caused by noxious stimuli and pathogens. ALI is characterized by marked acute inflammation with elevated alveolar cytokine levels. Mitogen-activated protein kinase (MAPK) pathways are involved in cytokine production, but the mechanisms that regulate these pathways remain poorly characterized. Here, we focused on the role of Sprouty-related EVH1-domain-containing protein (Spred)-2, a negative regulator of the Ras-Raf-extracellular signal-regulated kinase (ERK)-MAPK pathway, in lipopolysaccharide (LPS)-induced acute lung inflammation. METHODS: Wild-type (WT) mice and Spred-2(-/-) mice were exposed to intratracheal LPS (50 µg in 50 µL PBS) to induce pulmonary inflammation. After LPS-injection, the lungs were harvested to assess leukocyte infiltration, cytokine and chemokine production, ERK-MAPK activation and immunopathology. For ex vivo experiments, alveolar macrophages were harvested from untreated WT and Spred-2(-/-) mice and stimulated with LPS. In in vitro experiments, specific knock down of Spred-2 by siRNA or overexpression of Spred-2 by transfection with a plasmid encoding the Spred-2 sense sequence was introduced into murine RAW264.7 macrophage cells or MLE-12 lung epithelial cells. RESULTS: LPS-induced acute lung inflammation was significantly exacerbated in Spred-2(-/-) mice compared with WT mice, as indicated by the numbers of infiltrating leukocytes, levels of alveolar TNF-α, CXCL2 and CCL2 in a later phase, and lung pathology. U0126, a selective MEK/ERK inhibitor, reduced the augmented LPS-induced inflammation in Spred-2(-/-) mice. Specific knock down of Spred-2 augmented LPS-induced cytokine and chemokine responses in RAW264.7 cells and MLE-12 cells, whereas Spred-2 overexpression decreased this response in RAW264.7 cells. CONCLUSIONS: The ERK-MAPK pathway is involved in LPS-induced acute lung inflammation. Spred-2 controls the development of LPS-induced lung inflammation by negatively regulating the ERK-MAPK pathway. Thus, Spred-2 may represent a therapeutic target for the treatment of ALI.