水品 佳子

Caspase-11 is an inflammatory caspase that triggers an inflammatory response by regulating non-canonical NLRP3 inflammasome activation. Although the deficiency of both caspase-11 and caspase-1, another inflammatory caspase that functions as an executor of the inflammasome, prevents the development of atherosclerosis, the effect of caspase-11 deficiency alone on the development of atherosclerosis has not been fully evaluated. In the present study, we found that caspase-11 deficiency prevented the formation of the necrotic core, whereas it did not affect the development of atherosclerosis in Apoe-deficient mice. Notably, the infiltration of neutrophils into atherosclerotic lesions was attenuated by caspase-11 deficiency. RNA-seq analysis of stage-dependent expression of atherosclerotic lesions revealed that both upregulations of caspase-11 and neutrophil migration are common features of advanced atherosclerotic lesions. Furthermore, similar expression profiles were observed in unstable human plaque. These data suggest that caspase-11 regulates neutrophil recruitment and plaque destabilization in advanced atherosclerotic lesions.

Sepsis is a life-threatening syndrome, and its associated mortality is increased when cardiac dysfunction and damage (septic cardiomyopathy [SCM]) occur. Although inflammation is involved in the pathophysiology of SCM, the mechanism of how inflammation induces SCM in vivo has remained obscure. NLRP3 inflammasome is a critical component of the innate immune system that activates caspase-1 (Casp1) and causes the maturation of IL-1β and IL-18 as well as the processing of gasdermin D (GSDMD). Here, we investigated the role of the NLRP3 inflammasome in a murine model of lipopolysaccharide (LPS)-induced SCM. LPS injection induced cardiac dysfunction, damage, and lethality, which was significantly prevented in NLRP3-/- mice, compared to wild-type (WT) mice. LPS injection upregulated mRNA levels of inflammatory cytokines (Il6, Tnfa, and Ifng) in the heart, liver, and spleen of WT mice, and this upregulation was prevented in NLRP3-/- mice. LPS injection increased plasma levels of inflammatory cytokines (IL-1β, IL-18, and TNF-α) in WT mice, and this increase was markedly inhibited in NLRP3-/- mice. LPS-induced SCM was also prevented in Casp1/11-/- mice, but not in Casp11mt, IL-1β-/-, IL-1α-/-, or GSDMD-/- mice. Notably, LPS-induced SCM was apparently prevented in IL-1β-/- mice transduced with adeno-associated virus vector expressing IL-18 binding protein (IL-18BP). Furthermore, splenectomy, irradiation, or macrophage depletion alleviated LPS-induced SCM. Our findings demonstrate that the cross-regulation of NLRP3 inflammasome-driven IL-1β and IL-18 contributes to the pathophysiology of SCM and provide new insights into the mechanism underlying the pathogenesis of SCM.

Cryopyrin-associated periodic syndrome (CAPS) is an autoinflammatory syndrome caused by mutations of NLRP3 gene encoding cryopyrin. Familial cold autoinflammatory syndrome, the mildest form of CAPS, is characterized by cold-induced inflammation induced by the overproduction of IL-1β. However, the molecular mechanism of how mutated NLRP3 causes inflammasome activation in CAPS remains unclear. Here, we found that CAPS-associated NLRP3 mutants form cryo-sensitive aggregates that function as a scaffold for inflammasome activation. Cold exposure promoted inflammasome assembly and subsequent IL-1β release triggered by mutated NLRP3. While K+ efflux was dispensable, Ca2+ was necessary for mutated NLRP3-mediated inflammasome assembly. Notably, Ca2+ influx was induced during mutated NLRP3-mediated inflammasome assembly. Furthermore, caspase-1 inhibition prevented Ca2+ influx and inflammasome assembly induced by the mutated NLRP3, suggesting a feed-forward Ca2+ influx loop triggered by mutated NLRP3. Thus, the mutated NLRP3 forms cryo-sensitive aggregates to promote inflammasome assembly distinct from canonical NLRP3 inflammasome activation.

A 70-year-old woman with bilateral pleural effusion and respiratory failure was admitted to our hospital. Nephrotic syndrome due to minimal change disease had been diagnosed four months before admission. Because blood tests and a pleural fluid analysis did not reveal the etiology of her condition, we performed a video-assisted thoracoscopic pleural biopsy. No specific thoracoscopic findings were noted. The pathological findings revealed an increase in immunoglobulin G4 (IgG4)-positive cells; IgG4-related pleuritis was diagnosed. Her pleuritis improved with oral corticosteroid therapy. A further investigation was performed on previous kidney samples; however, the etiology of the nephrotic syndrome was not IgG4-related disease but minimal change disease.

Lung cancers with anaplastic lymphoma kinase (ALK) rearrangements are highly sensitive to treatment with ALK tyrosine kinase inhibitors (TKIs). Due to the very low rate of patients with squamous cell carcinoma enrolled in clinical trials, the efficacy of ALK inhibitors in patients with ALK-rearranged squamous cell carcinoma in the lung remains unclear. Herein, we present the case of a 70-year-old female patient with squamous cell lung cancer harboring the echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusion gene. The patient was treated with the ALK-TKI alectinib as first-line regimen and achieved a dramatic response without severe adverse events, demonstrating alectinib as a therapeutic option for patients with ALK-positive squamous cell carcinoma.

A 52-year-old man underwent pneumonectomy of the left lung for previously diagnosed primary spindle cell carcinoma (pT4aN1M0, stage III B) with programmed death-ligand 1 expression (tumor proportion score ≥95%) and without epidermal growth factor receptor gene mutation and anaplastic lymphoma kinase fusion gene. However, brain metastasis and chest wall tumor relapse occurred. Considering insufficient improvement with gamma knife treatment for brain metastasis and combination chemotherapy (paclitaxel, carboplatin, and bevacizumab), pembrolizumab monotherapy and palliative irradiation therapy for chest metastases were started after brain tumor volume reduction using craniotomy. Brain edema and chest wall metastases markedly improved following a pseudoprogression of the brain edema accompanied by a performance status decline; this effect continued until 11 cycles of pembrolizumab administration.

BACKGROUND AND OBJECTIVES: Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal lung disease. An increased expression of somatostatin receptor subtype 2 in patients with IPF was identified and lung fibroblasts expressed somatostatin receptors in vitro. In addition, somatostatin analogue inhibits the expression of transforming growth factor-β, insulin-like growth factor (IGF) -1, platelet-derived growth factor, and basic fibroblast growth factor. Therefore, we examined the effects of somatostatin analogue on bleomycin-induced pulmonary fibrosis in mice. In a similar model, it has been reported that administration of high-dose somatostatin analogs suppressed acute inflammation and subsequent pulmonary fibrosis. However, it was clarified that the same effect can be obtained even at the dose used in clinical practice. METHODS: C57BL/6 mice received a single tracheal instillation of bleomycin. After randomly allocated, mice were treated with subcutaneous injection of either normal saline or somatostatin analogue. RESULTS: Somatostatin analogue reduced the number of neutrophils and lymphocytes in bronchoalveolar lavage (BAL) and IGF-1 level in serum and BAL fluid and attenuated weight loss. The hydroxyproline content of the lung homogenates in somatostatin analogue treatment group was significantly lower than in that of normal saline treatment group. CONCLUSIONS: These results suggest that somatostatin analogue may attenuate pulmonary fibrosis after bleomycin treatment at the dose used in clinical practice.

BACKGROUND: Kartagener syndrome, an autosomal recessive disorder with a triad of chronic sinusitis, bronchiectasis, and situs inversus, is characterized by recurrent respiratory tract infections and chronic inflammation of the lung. Information on comorbidities other than infections in patients with Kartagener syndrome is currently limited. CASE PRESENTATION: A 39-year-old, non-smoking female was diagnosed with Kartagener syndrome and admitted to Saitama Medical Center, Jichi Medical University, Japan. Computed tomography revealed an endobronchial massive shadow at the ostial site of the right upper lobe bronchus with atelectasis of the right upper lobe. The mass was surgically resected and pathologically diagnosed as mucoepidermoid carcinoma. The lesion had no vascular invasions and no metastases to the lungs or lymph nodes. The surgical margin was negative for carcinoma. Following surgery, the patient has been in good condition. CONCLUSIONS: The present case showed different clinicopathological characteristics from those previously reported in cases of Kartagener syndrome complicated by carcinoma. To the best of our knowledge, this is the first reported case of a young, non-smoking female with comorbid Kartagener syndrome and pulmonary mucoepidermoid carcinoma. This case report may provide a new perspective on the complications of Kartagener syndrome.

Inflammation plays a pivotal role in the pathophysiology of gastric aspiration-induced acute lung injury (ALI). However, its mechanism remains unclear. In this study, we investigated the role of NLRP3 inflammasome-driven IL-1β production in a mouse model of acid aspiration-induced inflammation and ALI. Acid aspiration-induced inflammatory responses and ALI in wild-type mice were significantly attenuated in IL-1β-/- mice, but not NLRP3-/- mice. In vitro experiments revealed that severe acidic stress (pH 1.75) induced the processing of pro-IL-1β into its 18-kDa mature form (p18-IL-1β), which was different from the caspase-1-processed 17-kDa form (p17-IL-1β), in human THP-1 macrophages and primary murine macrophages. Deficiency of NLRP3 and caspase-1 had no effect on acidic stress-produced IL-1β. The production of IL-1β by severe acidic stress was prevented by inhibitors of serine proteases [4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride], but not of cysteine proteases (E-64), cathepsin G, or inflammasome. The cathepsin D inhibitor pepstatin A inhibited IL-1β production induced by mild acidic stress (pH 6.2) or lactic acid, but not severe acidic stress. Using mass spectrometry and processing-site mutants of pro-IL-1β, we identified D109 as a novel cleavage site of pro-IL-1β in response to severe acidic stress and calculated the theoretical molecular mass of the mature form to be 18.2 kDa. The bioactivity of acidic stress-produced IL-1β was confirmed by its ability to promote p38 phosphorylation and chemokine upregulation in alveolar epithelial cells. These findings demonstrate a novel mechanism of acid-induced IL-1β production and inflammation independent of NLRP3 inflammasome and provide new insights into the therapeutic strategies for aspiration pneumonitis and ALI.

Accumulating evidence suggests that IL-1β plays a pivotal role in the pathophysiology of hepatic ischemia-reperfusion (I/R) injury; however, the mechanism by which I/R triggers IL-1β production in the liver remains unclear. Recent data have shown that neutrophils contribute to hepatic I/R injury independently of the inflammasomes regulating IL-1β maturation. Thus, we investigated the role of neutrophils in IL-1β maturation and tissue injury in a murine model of hepatic I/R. IL-1β was released from the I/R liver and its deficiency reduced reactive oxygen species generation, apoptosis, and inflammatory responses, such as inflammatory cell infiltration and cytokine expression, thereby resulting in reduced tissue injury. Depletion of either macrophages or neutrophils also attenuated IL-1β release and hepatic I/R injury. In vitro experiments revealed that neutrophil-derived proteinases process pro-IL-1β derived from macrophages into its mature form independently of caspase-1. Furthermore, pharmacological inhibition of serine proteases attenuated IL-1β release and hepatic I/R injury in vivo. Taken together, the interaction between neutrophils and macrophages promotes IL-1β maturation and causes IL-1β-driven inflammation in the I/R liver. Both neutrophils and macrophages are indispensable in this process. These findings suggest that neutrophil-macrophage interaction is a therapeutic target for hepatic I/R injury and may also provide new insights into the inflammasome-independent mechanism of IL-1β maturation in the liver.

NLRP3 inflammasomes recognize non-microbial danger signals and induce release of proinflammatory cytokine interleukin (IL)-1β, leading to sterile inflammation in cardiovascular disease. Because sterile inflammation is involved in doxorubicin (Dox)-induced cardiotoxicity, we investigated the role of NLRP3 inflammasomes in Dox-induced cardiotoxicity. Cardiac dysfunction and injury were induced by low-dose Dox (15 mg/kg) administration in NLRP3-deficient (NLRP3(-/-)) mice but not in wild-type (WT) and IL-1β(-/-) mice, indicating that NLRP3 deficiency enhanced the susceptibility to Dox-induced cardiotoxicity independent of IL-1β. Although the hearts of WT and NLRP3(-/-) mice showed no significant difference in inflammatory cell infiltration, macrophages were the predominant inflammatory cells in the hearts, and cardiac IL-10 production was decreased in Dox-treated NLRP3(-/-) mice. Bone marrow transplantation experiments showed that bone marrow-derived cells contributed to the exacerbation of Dox-induced cardiotoxicity in NLRP3(-/-) mice. In vitro experiments revealed that NLRP3 deficiency decreased IL-10 production in macrophages. Furthermore, adeno-associated virus-mediated IL-10 overexpression restored the exacerbation of cardiotoxicity in the NLRP3(-/-) mice. These results demonstrated that NLRP3 regulates macrophage IL-10 production and contributes to the pathophysiology of Dox-induced cardiotoxicity, which is independent of IL-1β. Our findings identify a novel role of NLRP3 and provided new insights into the mechanisms underlying Dox-induced cardiotoxicity.

Inflammation plays an important role in the development of obesity and metabolic disorders; however, it has not been fully understood how inflammation occurs and is regulated in their pathogenesis. Low-molecular mass protein-7 (LMP7) is a proteolytic subunit of the immunoproteasome that shapes the repertoire of antigenic peptides on major histocompatibility complex class I molecule. In this study, we investigated the role of LMP7 in the development of obesity and metabolic disorders using LMP7-deficient mice. LMP7 deficiency conveyed resistant to obesity, and improved glucose intolerance and insulin sensitivity in mice fed with high-fat diet (HFD). LMP7 deficiency decreased pancreatic lipase expression, increased fecal lipid contents, and inhibited the increase of plasma triglyceride levels upon oral oil administration or HFD feeding. Using bone marrow-transferred chimeric mice, we found that LMP7 in both bone marrow- and non-bone marrow-derived cells contributes to the development of HFD-induced obesity. LMP7 deficiency decreased inflammatory responses such as macrophage infiltration and chemokine expression while it increased serum adiponection levels. These findings demonstrate a novel role for LMP7 and provide new insights into the mechanisms underlying inflammation in the pathophysiology of obesity and metabolic disorders.

Rhabdomyolysis is one of the main causes of community-acquired acute kidney injury (AKI). Although inflammation is involved in the pathogenesis of rhabdomyolysis-induced AKI (RIAKI), little is known about the mechanism that triggers inflammation during RIAKI. Recent evidence has indicated that sterile inflammation triggered by tissue injury can be mediated through multiprotein complexes called the inflammasomes. Therefore, we investigated the role of NLRP3 inflammasomes in the pathogenesis of RIAKI using a glycerol-induced murine rhabdomyolysis model. Inflammasome-related molecules were upregulated in the kidney of RIAKI. Renal tubular injury and dysfunction preceded leukocyte infiltration into the kidney during the early phase of RIAKI, and they were markedly attenuated in mice deficient in NLRP3, ASC, caspase-1, and interleukin (IL)-1β compared with those in wild-type mice. No difference in leukocyte infiltration was observed between wild-type and NLRP3-deficient mice. Furthermore, NLRP3 deficiency strikingly suppressed the expression of renal injury markers and inflammatory cytokines and apoptosis of renal tubular cells. These results demonstrated that NLRP3 inflammasomes contribute to inflammation, apoptosis, and tissue injury during the early phase of RIAKI and provide new insights into the mechanism underlying the pathogenesis of RIAKI.

Supplemental oxygen inhalation is frequently used to treat severe respiratory failure; however, prolonged exposure to hyperoxia causes hyperoxic acute lung injury (HALI), which induces acute respiratory distress syndrome and leads to high mortality rates. Recent investigations suggest the possible role of NLRP3 inflammasomes, which regulate IL-1β production and lead to inflammatory responses, in the pathophysiology of HALI; however, their role is not fully understood. In this study, we investigated the role of NLRP3 inflammasomes in mice with HALI. Under hyperoxic conditions, NLRP3(-/-) mice died at a higher rate compared with wild-type and IL-1β(-/-) mice, and there was no difference in IL-1β production in their lungs. Under hyperoxic conditions, the lungs of NLRP3(-/-) mice exhibited reduced inflammatory responses, such as inflammatory cell infiltration and cytokine expression, as well as increased and decreased expression of MMP-9 and Bcl-2, respectively. NLRP3(-/-) mice exhibited diminished expression and activation of Stat3, which regulates MMP-9 and Bcl-2, in addition to increased numbers of apoptotic alveolar epithelial cells. In vitro experiments revealed that alveolar macrophages and neutrophils promoted Stat3 activation in alveolar epithelial cells. Furthermore, NLRP3 deficiency impaired the migration of neutrophils and chemokine expression by macrophages. These findings demonstrate that NLRP3 regulates Stat3 signaling in alveolar epithelial cells by affecting macrophage and neutrophil function independent of IL-1β production and contributes to the pathophysiology of HALI.

Increasing evidence indicates that caspase recruitment domain (CARD)-mediated caspase-1 (CASP1) assembly is an essential process for its activation and subsequent interleukin (IL)-1β release, leading to the initiation of inflammation. Both CARD16 and CARD17 were previously reported as inhibitory homologs of CASP1; however, their molecular function remains unclear. Here, we identified that oligomerization activity allows CARD16 to function as a CASP1 activator. We investigated the molecular characteristics of CARD16 and CARD17 in transiently transfected HeLa cells. Although both CARD16 and CARD17 interacted with CASP1CARD, only CARD16 formed a homo-oligomer. Oligomerized CARD16 formed a filament-like structure with CASP1CARD and a speck with apoptosis-associated speck-like protein containing a CARD. A filament-like structure formed by CARD16 promoted CASP1 filament assembly and IL-1β release. In contrast, CARD17 did not form a homo-oligomer or filaments and inhibited CASP1-dependent IL-1β release. Mutated CARD16D27G, mimicking the CARD17 amino acid sequence, formed a homo-oligomer but failed to form a filament-like structure. Consequently, CARD16D27G weakly promoted CASP1 filament assembly and subsequent IL-1β release. These results suggest that oligomerized CARD16 promotes CARD-mediated molecular assembly and CASP1 activation.

BACKGROUND: Type I interferons (IFNs), including IFN-alpha (IFNA) and IFN-beta (IFNB), have anti-inflammatory properties and are used to treat patients with autoimmune and inflammatory disorders. However, little is known of the role of IFN-tau (IFNT), a type I IFN produced by ruminant animals for inflammation. Because IFNB has recently been shown to inhibit nucleotide-binding oligomerization domain-like receptor, pyrin domain-containing 3 (NLRP3) inflammasome activation and subsequent secretion of the potent inflammatory cytokine interleukin (IL)-1β, we examined the effects of ruminant IFNT on NLRP3 inflammasome-mediated IL-1β secretion in human THP-1 macrophages. METHODS AND RESULTS: IFNT dose-dependently inhibited IL-1β secretion induced by nano-silica, a well-known activators of NLRP3 inflammasomes, in human macrophages primed with lipopolysaccharide (LPS, TLR4 agonist) and Pam3CSK4 (TLR1/2 agonist). IFNT also suppressed phagocytosis of nano-silica and reactive oxygen species (ROS) generation. Western blot analysis showed that IFNT inhibited both pro-IL-1β and mature IL-1β. In addition, real-time RT-PCR analysis showed that IFNT suppressed IL-1β mRNA expression induced by LPS and Pam3CSK4. Although nano-silica particles did not induce IL-10 secretion, IFNT induced IL-10 secretion in a dose-dependent manner. Furthermore, IFNT-suppressed IL-1β secretion was restored by anti-IL-10 neutralizing antibody. CONCLUSIONS: Ruminant IFNT inhibits NLRP3 inflammasome-driven IL-1β secretion in human macrophages via multiple pathways, including the uptake of nano-silica particles, generation of ROS, and IL-10-mediated inhibition of pro-IL-1β induction. It may be a therapeutic alternative to IFNA and IFNB.

A 26-year-old man presented at our hospital in 2008 to undergo detailed investigations as part of a routine health examination. Chest computed tomography (CT) showed linear and reticular opacities with, in part, diffuse calcification in the lung fields bilaterally. A surgical lung biopsy was performed and the histological findings were compatible with a diagnosis of diffuse pulmonary ossification (DPO) of the dendriform type. DPO usually occurs as a secondary disease. As the histological changes in interstitial fibrosis were minimal rather than diffuse and not significant enough to be regarded as interstitial pneumonia, we considered this to be an idiopathic case. However, the findings appear to suggest that inflammation and fibrosis were associated with ossification.

OBJECTIVE: Renal angiomyolipomas (R-AMLs) are major complications of lymphangioleiomyomatosis (LAM). The objective of this study was to better understand the influence of R-AMLs in patients with LAM on the prognosis and other clinical factors related to respiration, and to investigate the management of R-AMLs in patients with LAM. PATIENTS AND METHODS: We retrospectively investigated the clinical features of 7 patients with LAM [4 were TSC (Tuberous sclerosis complex)-LAM and 3 were S (sporadic)-LAM] complicated by R-AMLs admitted to our hospital from 1997 to 2008. RESULTS: All patients were females and the mean age at diagnosis of LAM was 40.7 years (31.7 years for TSC-LAM and 52.7 years for S-LAM). Although 5 patients had symptoms related to R-AMLs, only 1 patient experienced symptoms related to R-AMLs at the time of diagnosis. Five patients had bilateral and 2 patients had unilateral R-AMLs. R-AMLs ruptured in 4 cases (3 patients were TSC-LAM) including 2 patients in whom they ruptured bilaterally, and who underwent bilateral nephrectomy. In 1 case, unilateral R-AMLs grew larger and appeared on the other side during the follow-up period. CONCLUSION: Although only rare cases of LAM show symptoms related to R-AMLs initially, R-AMLs are a notable complication. To avoid nephrectomy, R-AMLs should be diagnosed when they are small and should be followed up carefully by periodic echograms or CT scans.

IL-33 is a member of the IL-1 family and has been identified as an agonist of ST2L. IL-33 drives the production of Th2-associated cytokines and IgE, and IL-33 administration induces eosinophilia and hypertrophy of bronchial epithelial cells, as well as mucus secretion in vivo. Such changes resemble pathological findings in bronchial asthma (BA). In this study, we investigated the relationship between IL-33 and BA by evaluating serum IL-33 levels. Serum was obtained from BA patients (n = 20), emphysema patients (n = 5) and from non-smoking healthy controls (n = 8). IL-33 levels were assayed by enzyme-linked immunosorbent assay. Then, we divided BA patients according to 5 factors; (1) IgE concentration, (2) eosinophil count, (3) current treatment, (4) classification of severity, and (5) smoking status. Atopic BA patients showed significantly higher IL-33 levels than non-atopic patients. IL-33 was significantly higher in untreated patients, and in the moderate and severely affected groups. Smoking BA and emphysema patients had lower levels than nonsmoking BA patients. Eosinophil counts were not related to IL-33 levels. The present study suggests that IL-33 is closely associated with IgE levels and the exacerbation of BA. We speculated that IL-33 elevation is responsible for the maintenance of airway inflammation and hypersensitivity. It is possible that low IL-33 levels in smokers are caused by the deterioration of the airway epithelium and endothelium.

A 44-year-old woman who had undergone hystero-oophorectomy for uterine sarcoma presented to our hospital with palindromic pneumothorax and her chest CT revealed multiple cystic lesions. After admission video-assisted thoracoscopic surgery (VATS) showed the pulmonary lesions to be primarily leiomyoma, however, further examination revealed that her uterine sarcoma resected in 2000 exhibited not only mitosis but also venous invasion. We therefore considered her lung tumors as metastases from uterine leiomyosarcoma. Cases of secondary spontaneous pneumothorax (SSP) due to pulmonary metastases are rare and almost half are from mesenchymal tumors. Thin-wall cavities and cysts are formed by a check-valve mechanism in the process of pulmonary metastases formation. When multiple thin-wall cavities and cysts are found in the lung, pulmonary metastases should be considered as one of the causes, and pathological specimens obtained in past illness should be re-examined in detail.