Matrix metalloproteinase-2 and matrix metalloproteinase-9 in mice with ocular toxocariasis.

In ocular toxocariasis, Toxocara canis-induced inflammatory reaction can lead to eye destruction and granuloma, which is formed by immune cell infiltration and concurrent extensive remodeling tissue. Herein, the histomorphology of granuloma and proteinase production in the eye of T. canis-infected BALB/c mice were investigated. Pathological effects substantially increased after the infection culminated in a severe leukocyte infiltration and granuloma formation from days 4 to 56 post-inoculation. The matrix metalloproteinase (MMP)-2 and MMP-9 activities remarkably increased, compared with those of uninfected control, by gelatin zymography and Western blot analysis in ocular toxocariasis. Granuloma formation had a remarkably positive correlation with MMP-2 and MMP-9 levels. We suggested that T. canis larvae and leukocytes infiltrated from blood vessel both migrated into corpus adiposum orbitae. Activated leukocytes secreted MMP-2 and MMP-9, leading to fibronectin degradation. The imbalance of MMP-2/TIMP-2 and MMP-9/TIMP-1 may play a role in inflammatory cell infiltration and extracellular matrix degradation, forming granuloma, in ophthalmological pathogenesis of T. canis infection.

The expression of Indoleamine 2, 3-dioxygenase (IDO) is reduced in granulomas from BCG vaccinated cattle compared to granulomas from unvaccinated controls after experimental challenge with Mycobacterium bovis.

Bovine tuberculosis (bTB), mainly caused by Mycobacterium bovis (M. bovis), is a major economic disease of livestock worldwide. Vaccination is considered as a potentially sustainable adjunct to the current control strategy. Cattle vaccination with the live attenuated M. bovis bacillus Calmette-Guerin (BCG) confers variable protection; the reasons for this variability are not understood. Indoleamine 2, 3-dioxygenase (IDO), through the catalysis of tryptophan, is thought to have an immunoregulatory role in the immune response to Mycobacterium tuberculosis (M. tuberculosis). In this work, we used immunohistochemistry and digital image analysis to evaluate the presence of IDO in granulomas at different stages of development in cattle that had been BCG-vaccinated or not and then challenged with M. bovis. Our results show that the expression of IDO in granulomas from non-vaccinated M. bovis challenged animals is higher than in granulomas from BCG-vaccinated M. bovis challenged animals. Thus, it is possible that vaccination with BCG prevents the induction of what are thought to be host immunosuppressive pathways by M. bovis, which contribute to pathology during the disease.

Pulmonary metastatic colonisation and granulomas in NOX2-deficient mice.

Metastasis is the leading cause of death in cancer patients, and successful colonisation of a secondary organ by circulating tumour cells (CTCs) is the rate-limiting step of this process. We used tail-vein injection of B16-F10 melanoma cells into mice to mimic the presence of CTCs and to allow for the assessment of host (microenvironmental) factors that regulate pulmonary metastatic colonisation. We found that mice deficient for the individual subunits of the NADPH oxidase of myeloid cells, NOX2 (encoded by Cyba, Cybb, Ncf1, Ncf2, and Ncf4), all showed decreased pulmonary metastatic colonisation. To understand the role of NOX2 in controlling tumour cell survival in the pulmonary microenvironment, we focused on Cyba-deficient (Cybatm1a ) mice, which showed the most significant decrease in metastatic colonisation. Interestingly, histological assessment of pulmonary metastatic colonisation was not possible in Cybatm1a mice, owing to the presence of large granulomas composed of galectin-3 (Mac-2)-positive macrophages and eosinophilic deposits; granulomas of variable penetrance and severity were also found in Cybatm1a mice that were not injected with melanoma cells, and these contributed to their decreased survival. The decreased pulmonary metastatic colonisation of Cybatm1a mice was not due to any overt defects in vascular permeability, and bone marrow chimaeras confirmed a role for the haematological system in the reduced metastatic colonisation phenotype. Examination of the lymphocyte populations, which are known key regulators of metastatic colonisation, revealed an enhanced proportion of activated T and natural killer cells in the lungs of Cybatm1a mice, relative to controls. The reduced metastatic colonisation, presence of granulomas and altered immune cell populations observed in Cybatm1a lungs were mirrored in Ncf2-deficient (Ncf2tm1a ) mice. Thus, we show that NOX2 deficiency results in both granulomas and the accumulation of antitumoural immune cells in the lungs that probably mediate the decreased pulmonary metastatic colonisation. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Adjunct antibody administration with standard treatment reduces relapse rates in a murine tuberculosis model of necrotic granulomas.

Matrix metalloproteinase (MMP)-9 is a zinc-dependent protease associated with early immune responses to Mycobacterium tuberculosis infection, macrophage recruitment and granuloma formation. We evaluated whether adjunctive inhibition of MMP-9 could improve the response to standard TB treatment in a mouse model that develops necrotic lesions. Six weeks after an aerosol infection with M. tuberculosis, C3HeB/FeJ mice received standard TB treatment (12 weeks) comprising rifampin, isoniazid and pyrazinamide alone or in combination with either anti-MMP-9 antibody, etanercept (positive control) or isotype antibody (negative control) for 6 weeks. Anti-MMP-9 and the isotype control had comparable high serum exposures and expected terminal half-life. The relapse rate in mice receiving standard TB treatment was 46.6%. Compared to the standard TB treatment, relapse rates in animals that received adjunctive treatments with anti-MMP-9 antibody or etanercept were significantly decreased to 25.9% (P = 0.006) and 29.8% (P = 0.019) respectively, but were not different from the arm that received the isotype control antibody (25.9%). Immunostaining demonstrated localization of MMP-9 primarily in macrophages in both murine and human lung tissues infected with M. tuberculosis, suggesting the importance of MMP-9 in TB pathogenesis. These data suggest that the relapse rates in M. tuberculosis-infected mice may be non-specifically improved by administration of antibodies in conjunction with standard TB treatments. Future studies are needed to evaluate the mechanism(s) leading to improved outcomes with adjunctive antibody treatments.

ACE phenotyping in Gaucher disease.

BACKGROUND: Gaucher disease is characterized by the activation of splenic and hepatic macrophages, accompanied by dramatically increased levels of angiotensin-converting enzyme (ACE). To evaluate the source of the elevated blood ACE, we performed complete ACE phenotyping using blood, spleen and liver samples from patients with Gaucher disease and controls. METHODS: ACE phenotyping included 1) immunohistochemical staining for ACE; 2) measuring ACE activity with two substrates (HHL and ZPHL); 3) calculating the ratio of the rates of substrate hydrolysis (ZPHL/HHL ratio); 4) assessing the conformational fingerprint of ACE by evaluating the pattern of binding of monoclonal antibodies to 16 different ACE epitopes. RESULTS: We show that in patients with Gaucher disease, the dramatically increased levels of ACE originate from activated splenic and/or hepatic macrophages (Gaucher cells), and that both its conformational fingerprint and kinetic characteristics (ZPHL/HHL ratio) differ from controls and from patients with sarcoid granulomas. Furthermore, normal spleen was found to produce high levels of endogenous ACE inhibitors and a novel, tightly-bound 10-30 kDa ACE effector which is deficient in Gaucher spleen. CONCLUSIONS: The conformation of ACE is tissue-specific. In Gaucher disease, ACE produced by activated splenic macrophages differs from that in hepatic macrophages, as well as from macrophages and dendritic cells in sarcoid granulomas. The observed differences are likely due to altered ACE glycosylation or sialylation in these diseased organs. The conformational differences in ACE may serve as a specific biomarker for Gaucher disease.

Evaluation of anti-inflammatory, analgesic activities, and side effects of some pyrazole derivatives.

BACKGROUND AND PURPOSE: Non-steroidal anti-inflammatory drugs are associated with several side effects, such as gastrointestinal mucosal damage, renal toxicity, and cardiovascular side effects. Aiming to find a novel analgesic/anti-inflammatory drug with minimal side effects, the present study was designed to screen and evaluate some newly synthesized pyrazole derivatives. METHOD: Anti-inflammatory activity using carrageenan-induced rat paw edema and cotton-pellet-induced granuloma, COX-1/COX-2 selectivity using thin layer chromatography, and analgesic using hot plate and tail flick tests as well as ulcerogenic and renal side effects of the ten compounds were assessed. RESULTS AND DISCUSSION: The results of the carrageenan-induced rat paw edema showed that the carboxyphenylhydrazone derivative (N9) was more potent than the chlorophenyl counterpart (N8) with a relative activity compared to celecoxib of 1.08 and -0.13, respectively, after 1 h. Even though this is true, N9 caused significant increase in the ulcer index, creatinine, and Blood Urea Nitrogen levels. The cotton granuloma test showed that the carboxyphenylhydrazone derivative (N7) was also more potent than its chlorophenyl counterpart (N6) with a relative activity compared to celecoxib of 1.13 and 0.86, respectively. Moreover, adding an acetyl not only increased the anti-inflammatory activity from a relative activity compared to celecoxib of 0.57-1.17 for the compounds X4 and N5, respectively, in the granuloma test, but also increased the selectivity toward COX-2 from 0.197 to 47.979. CONCLUSION: As a conclusion, from the ten compounds analyzed, N5 and N7 showed promising results as anti-inflammatory/analgesic agents with low ulcerogenicity and nephrotoxicity and thus should be further analyzed to determine the ED50 and other side effects.

Phospholipase Cγ2 Is Required for Luminal Expansion of the Epididymal Duct during Postnatal Development in Mice.

Phospholipase Cγ2 (PLCγ2)-deficient mice exhibit misconnections of blood and lymphatic vessels, and male infertility. However, the cell type responsible for vascular partitioning and the mechanism for male infertility remain unknown. Accordingly, we generated a mouse line that conditionally expresses endogenous Plcg2 in a Cre/loxP recombination-dependent manner, and found that Tie2-Cre- or Pf4-Cre-driven reactivation of Plcg2 rescues PLCγ2-deficient mice from the vascular phenotype. By contrast, male mice rescued from the vascular phenotype exhibited epididymal sperm granulomas. As judged from immunostaining, PLCγ2 was expressed in clear cells in the epididymis. PLCγ2 deficiency did not compromise differentiation of epididymal epithelial cells, including clear cells, and tube formation at postnatal week 2. However, luminal expansion of the epididymal duct was impaired during the prepubertal period, regardless of epithelial cell polarity and tube architecture. These results suggest that PLCγ2-deficient clear cells cause impaired luminal expansion, stenosis of the epididymal duct, attenuation of luminal flow, and subsequent sperm granulomas. Clear cell-mediated luminal expansion is also supported by the observation that PLCγ2-deficient males were rescued from infertility by epididymal epithelium-specific reactivation of Plcg2, although the edematous and hemorrhagic phenotype associated with PLCγ2 deficiency also caused spontaneous epididymal sperm granulomas in aging males. Collectively, our findings demonstrate that PLCγ2 in clear cells plays an essential role in luminal expansion of the epididymis during the prepubertal period in mice, and reveal an unexpected link between PLCγ2, clear cells, and epididymal development.

Gene-expression analysis of matrix metalloproteinases 1 and 2 and their tissue inhibitors in chronic periapical inflammatory lesions.

BACKGROUND: Periapical inflammatory lesions have been investigated previously, but understanding of pathogenesis of these lesions (granulomas and radicular cysts) at the molecular level is still questionable. Matrix metalloproteinases (MMPs) are enzymes involved in the development of periapical pathology, specifically inflammation and tissue destruction. To elucidate pathogenesis of periapical granulomas and radicular cysts, we undertook a detailed analysis of gene expression of MMP-1, MMP-2 and their tissue inhibitors, TIMP-1 and TIMP-2. METHODS: A total of 149 samples were analyzed using real-time PCR (59 radicular cysts, 50 periapical granulomas and 40 healthy gingiva samples as controls) for expression of MMP-1, MMP-2, TIMP-1 and TIMP-2 genes. The determination of best reference gene for expression analysis of periapical lesions was done using a panel of 12 genes. RESULTS: We have shown that ß-actin and GAPDH are not the most stable reference controls for gene expression analysis of inflammatory periapical tissues and healthy gingiva. The most suitable reference gene was determined to be SDHA (a succinate dehydrogenase complex, subunit A, flavoprotein [Fp]). We found that granulomas (n = 50) and radicular cysts (n = 59) exhibited significantly higher expression of all four examined genes, MMP-1, MMP-2, TIMP-1, and TIMP-2, when compared to healthy gingiva (n = 40; P < 0.05). CONCLUSION: This study has confirmed that the expression of MMP-1, MMP-2, TIMP-1, and TIMP-2 genes is important for the pathogenesis of periapical inflammatory lesions. Since the abovementioned markers were not differentially expressed in periapical granulomas and radicular cysts, the challenge of finding the genetic differences between the two lesions still remains.

Helminth-induced arginase-1 exacerbates lung inflammation and disease severity in tuberculosis.

Parasitic helminth worms, such as Schistosoma mansoni, are endemic in regions with a high prevalence of tuberculosis (TB) among the population. Human studies suggest that helminth coinfections contribute to increased TB susceptibility and increased rates of TB reactivation. Prevailing models suggest that T helper type 2 (Th2) responses induced by helminth infection impair Th1 immune responses and thereby limit Mycobacterium tuberculosis (Mtb) control. Using a pulmonary mouse model of Mtb infection, we demonstrated that S. mansoni coinfection or immunization with S. mansoni egg antigens can reversibly impair Mtb-specific T cell responses without affecting macrophage-mediated Mtb control. Instead, S. mansoni infection resulted in accumulation of high arginase-1-expressing macrophages in the lung, which formed type 2 granulomas and exacerbated inflammation in Mtb-infected mice. Treatment of coinfected animals with an antihelminthic improved Mtb-specific Th1 responses and reduced disease severity. In a genetically diverse mouse population infected with Mtb, enhanced arginase-1 activity was associated with increased lung inflammation. Moreover, in patients with pulmonary TB, lung damage correlated with increased serum activity of arginase-1, which was elevated in TB patients coinfected with helminths. Together, our data indicate that helminth coinfection induces arginase-1-expressing type 2 granulomas, thereby increasing inflammation and TB disease severity. These results also provide insight into the mechanisms by which helminth coinfections drive increased susceptibility, disease progression, and severity in TB.

Schistosome infection-derived Hepatic Stellate Cells are cellular source of prostaglandin D2: role in TGF-ß-stimulated VEGF production.

Hepatic Stellate Cells (HSCs) play a crucial role in pathogenesis of liver inflammation and fibrosis. During chronic liver injury, HSCs lose vitamin A and transform into myofibroblastic cells. In schistosomal granulomas, these activated HSCs are called GR-HSCs. Schistosomal-triggered hepatic fibrogenesis has TGF-ß as the most potent fibrogenic stimulus, that also controls gene expression of the angiogenic molecule VEGF in HSCs. COX-dependent production of prostaglandins (PGs) also play role in angiogenic processes. Besides angiogenic roles, prostanoids control immunomodulation of Schistosoma mansoni infection. Specifically, schistosoma-derived PGD2 has emerged as a key parasite regulator of immune defense evasion, while no role is still established to host PGD2. Therefore, the aim of this work is to investigate the ability of GR-HSCs to synthesize COX-derived PGD2 and a potential role of this prostanoid in VEGF production by GR-HSCs in vitro. Here, we confirmed that GR-HSCs express COX-2, which displayed perinuclear localization. While unstimulated GR-HSCs produce basal levels of PGD2, TGF-ß stimulation besides increasing COX2- mRNA levels, enhanced synthesis/secretion of PGD2 in GR-HSCs supernatant. Moreover, GR-HSCs-derived PGD2 mediate VEGF production by TGF-ß-stimulated GR-HSCs, since the pre-treatment with HQL-79, an inhibitor of hematopoietic PGD synthase inhibited both PGD2 synthesis and VEGF secretion by TGF-ß-stimulated GR-HSCs. All together, our findings show an autocrine/paracrine activity of GR-HSCs-derived PGD2 on TGF-ß-induced VEGF production by GR-HSCs, unveiling a role for PGD2 as important regulator of HSCs activation in hepatic granulomas from schistosome infected mice.

Design, synthesis, characterization and in vitro and in vivo anti-inflammatory evaluation of novel pyrazole-based chalcones.

Abstract A series of novel pyrazole-based chalcones have been designed, synthesized from 1-methyl-5-(2,4,6-trimethoxyphenyl)-1H-pyrazole (6). The structures of regioisomers 6 and 7 were determined by 2D (1)H-(1)H COSY, (1)H-(13)C HSQC and (1)H-(13)C HMBC experiments. The newly synthesized compounds were tested for their inhibitory activity against COX-1 and COX-2 using an in vitro cyclooxygenase (COX) inhibition assay. Moreover, they were investigated in vivo for their anti-inflammatory activities using carrageenan-induced rat paw edema model for acute inflammation and cotton pellet-induced granuloma model for chronic inflammation. All the synthesized compounds showed potential to demonstrate anti-inflammatory activities, of particular interest compounds 10i, 10e, 10f, and 10h were found to be potent anti-inflammatory agents.

Alveolar and intraparenchymal proteasome in sarcoidosis.

BACKGROUND: In sarcoidosis, an antigen specific immune response is a putative mechanism, resulting in granulomatous inflammation. Since the proteasome is involved in antigen presentation, alterations in the alveolar and parenchymal proteasomal system may be a feature of sarcoidosis. OBJECTIVES: To explore the role of proteasomes and immunoproteasomes in sarcoidosis. METHODS: Total proteasome concentration and activity was assessed in bronchoalveolar lavage (BAL) supernatant obtained from sarcoidosis patients (n = 67) and healthy controls (n = 18) using ELISA and cleavage of specific fluorogenic substrates (±epoxomicin), respectively. Immunohistochemistry of lung tissue sections and immunocytochemistry of BAL macrophages for immunoproteasome was performed in sarcoidosis patients and controls. RESULTS: Proteasome was present in BAL supernatants of all sarcoidosis patients. In sarcoidosis, abundant immunoproteasome staining was seen in pneumocytes type II and granulomas. Total proteasome concentration was greater in active sarcoidosis, stages II (101 ng/ml ± 79; p = 0.009) and III (119 ng/ml ± 66; p = 0.012), than in inactive sarcoidosis or in healthy controls (35 ng/ml ± 34). In the absence of epoxomicin, all fluorogenic substrates were hydrolyzed by BAL supernatant of sarcoidosis patients and controls. CONCLUSIONS: Patients with active sarcoidosis but not healthy controls demonstrate immunoproteasome in the lung tissue and in granulomas. Thus, the putative immune response in sarcoidosis may be mediated or sustained by the proteasomal system.

Macrophage arginase-1 controls bacterial growth and pathology in hypoxic tuberculosis granulomas.

Lung granulomas develop upon Mycobacterium tuberculosis (Mtb) infection as a hallmark of human tuberculosis (TB). They are structured aggregates consisting mainly of Mtb-infected and -uninfected macrophages and Mtb-specific T cells. The production of NO by granuloma macrophages expressing nitric oxide synthase-2 (NOS2) via l-arginine and oxygen is a key protective mechanism against mycobacteria. Despite this protection, TB granulomas are often hypoxic, and bacterial killing via NOS2 in these conditions is likely suboptimal. Arginase-1 (Arg1) also metabolizes l-arginine but does not require oxygen as a substrate and has been shown to regulate NOS2 via substrate competition. However, in other infectious diseases in which granulomas occur, such as leishmaniasis and schistosomiasis, Arg1 plays additional roles such as T-cell regulation and tissue repair that are independent of NOS2 suppression. To address whether Arg1 could perform similar functions in hypoxic regions of TB granulomas, we used a TB murine granuloma model in which NOS2 is absent. Abrogation of Arg1 expression in macrophages in this setting resulted in exacerbated lung granuloma pathology and bacterial burden. Arg1 expression in hypoxic granuloma regions correlated with decreased T-cell proliferation, suggesting that Arg1 regulation of T-cell immunity is involved in disease control. Our data argue that Arg1 plays a central role in the control of TB when NOS2 is rendered ineffective by hypoxia.

Heme catabolism by heme oxygenase-1 confers host resistance to Mycobacterium infection.

Heme oxygenases (HO) catalyze the rate-limiting step of heme degradation. The cytoprotective action of the inducible HO-1 isoform, encoded by the Hmox1 gene, is required for host protection against systemic infections. Here we report that upregulation of HO-1 expression in macrophages (M) is strictly required for protection against mycobacterial infection in mice. HO-1-deficient (Hmox1(-/-)) mice are more susceptible to intravenous Mycobacterium avium infection, failing to mount a protective granulomatous response and developing higher pathogen loads, than infected wild-type (Hmox1(+/+)) controls. Furthermore, Hmox1(-/-) mice also develop higher pathogen loads and ultimately succumb when challenged with a low-dose aerosol infection with Mycobacterium tuberculosis. The protective effect of HO-1 acts independently of adaptive immunity, as revealed in M. avium-infected Hmox1(-/-) versus Hmox1(+/+) SCID mice lacking mature B and T cells. In the absence of HO-1, heme accumulation acts as a cytotoxic pro-oxidant in infected M, an effect mimicked by exogenous heme administration to M. avium-infected wild-type M in vitro or to mice in vivo. In conclusion, HO-1 prevents the cytotoxic effect of heme in M, contributing critically to host resistance to Mycobacterium infection.

Selective inhibition of PDE4 in Wistar rats can lead to dilatation in testis, efferent ducts, and epididymis and subsequent formation of sperm granulomas.

Testicular tubular dilatation and degeneration and epididymal sperm granulomas were frequently seen in 4-week toxicity studies using different phosphodiesterase-4 (PDE4) inhibitors in Wistar rats, including the prototypic PDE4 inhibitor BYK169171. To investigate the pathogenesis of testicular and epididymal lesions, a time course study with BYK169171 was conducted with sequential necropsies after 7, 14, 21, and 28 days of treatment. After 7 days, a dilatation of efferent ducts and of the initial segment of the epididymis and a subacute interstitial inflammation were seen followed by a diffuse dilatation of seminiferous tubules in the testis. Dilatation and inflammation were most pronounced after 14 days. Single animals also exhibited vascular necrosis in the inflamed interstitium. Although dilatation decreased later in the study, the incidence and severity of tubular degeneration increased from 14 days onward. Sperm granulomas developed in efferent ducts and in the caput and cauda of the epididymis after 14 days. Our results demonstrate a clear time course of PDE4 inhibition-induced lesions, with dilatation preceding sperm granuloma formation. We conclude that the most likely mechanism of toxicity is a disturbance of fluid homeostasis in efferent and epididymal ducts resulting in abnormal luminal fluid and sperm contents, epithelial damage at specific sites of the excurrent duct system, sperm leakage, and granuloma formation.

Granuloma correlates of protection against tuberculosis and mechanisms of immune modulation by Mycobacterium tuberculosis.

BACKGROUND: The BCG vaccine is ineffective against adult tuberculosis. Hence, new antituberculosis vaccines are needed. Correlates of protection against tuberculosis are not known. We studied the effects of BCG vaccination on gene expression in tuberculosis granulomas using macaques. METHODS: Macaques were BCG-vaccinated or sham-vaccinated and then challenged with virulent Mycobacterium tuberculosis. Lung lesions were used for comparative transcriptomics. RESULTS: Vaccinated macaques were protected with lower bacterial burden and immunopathology. Lesions from BCG-vaccinated nonhuman primates (NHPs) showed a better balance of α- and ß-chemokine gene expression with higher levels of ß-chemokine expression relative to nonvaccinated animals. Consistent with this, sham-vaccinated macaques recruited fewer macrophages relative to neutrophils in their lungs. The expression of indoleamine 2,3-dioxygenase (IDO), a known immunosuppressor, was significantly higher in both week 5 and 10 lesions from sham-vaccinated, relative to BCG-vaccinated, NHPs. IDO expression was primarily limited to the nonlymphocytic region of the lesions, within the inner ring structure surrounding the central necrosis. CONCLUSIONS: Our study defines lung gene expression correlates of protective response against tuberculosis, relative to disease, which can potentially be employed to assess the efficacy of candidate antituberculosis vaccines. Mycobacterium tuberculosis may modulate protective immune responses using diverse mechanisms, including increased recruitment of inflammatory neutrophils and the concomitant use of IDO to modulate inflammation.

Heme oxygenase-1 promotes granuloma development and protects against dissemination of mycobacteria.

Non-tuberculous mycobacterial (NTM) infections occur in both immunocompromised and immunocompetent hosts and are an increasingly recognized cause of morbidity and mortality. The hallmark of pulmonary mycobacterial infections is the formation of granuloma in the lung. Our study focuses on the role of heme oxygenase-1 (HO-1), a cytoprotective enzyme, in the regulation of granuloma development and maturation following infection with Mycobacterium avium. We examined the role of HO-1 in regulating monocyte chemoattractant protein-1 (MCP-1) and chemokine receptor 2 (CCR2), two molecules involved in monocyte-macrophage cell trafficking after infection. We showed that RAW 264.7 mouse monocytes exposed to M. avium expressed HO-1 and MCP-1. Inhibition of HO by zinc protoporphyrin-IX led to inhibition of MCP-1 and increased expression of CCR2, its cognate receptor. HO-1⁻/⁻ mice did not develop organized granuloma in their lungs, had higher lung colony forming unit of M. avium when infected with intratracheal M. avium, and had loose collections of inflammatory cells in the lung parenchyma. Mycobacteria were found only inside defined granulomas but not outside granuloma in the lungs of HO-1⁺/⁺ mice. In HO-1⁻/⁻ mice, mycobacteria were also found in the liver and spleen and showed increased mortality. Peripheral blood monocytes isolated from GFP⁺ mice and given intravenously to HO-1⁺/⁺ mice localized into tight granulomas, while in HO-1⁻/⁻ mice they remained diffusely scattered in areas of parenchymal inflammation. Higher MCP-1 levels were found in bronchoalveolar lavage fluid of M. avium infected HO-1(-/-) mice and CCR2 expression was higher in HO-1⁻/⁻ alveolar macrophages when compared with HO-1⁺/⁺ mice. CCR2 expression localized to granuloma in HO-1⁺/⁺ mice but not in the HO-1⁻/⁻ mice. These findings strongly suggest that HO-1 plays a protective role in the control of M. avium infection.

Arginase-1 expression in granulomas of tuberculosis patients.

Mycobacterium tuberculosis (Mtb) is an intracellular pathogen able to survive and multiply within macrophages. Several mechanisms allow this bacterium to escape macrophage microbicidal activity. Mtb may interfere with the ability of mouse macrophages to produce antibactericidal nitric oxide, by inducing the expression of arginase 1 (Arg1). It remains unclear whether this pathway has a role in humans infected with Mtb. In this study, we investigated the expression of Arg1 in granulomas of human lung tissues from patients with tuberculosis. We show that Arg1 is expressed not only in granuloma-associated macrophages, but also in type II pneumocytes.

α-amylase crystalloid granuloma of the parotid gland: case report and review of the literature.

We report a case of α-amylase crystalloid granuloma of the parotid gland in a 65-year-old Japanese woman. Histopathologically, the lesion comprised cystlike dilatation of the ducts and foreign body granulomas, with deposits of numerous crystalloid structures. The crystalloids were eosinophilic and varied in size and shape. Immunohistochemically, the crystalloids were positive for α-amylase. Immunoelectron microscopy showed the crystalloids to be cuboidal or rectangular in shape with irregularly shaped central spaces. We discuss this rare condition and review the literature on α-amylase crystalloids.