Karla Fernandes

Prostaglandin mediates IL-23/IL-17-induced neutrophil migration in inflammation by inhibiting IL-12 and IFNγ production

IL-23/IL-17-induced neutrophil recruitment plays a pivotal role in rheumatoid arthritis (RA). However, the mechanism of the neutrophil recruitment is obscure. Here we report that prostaglandin enhances the IL-23/IL-17-induced neutrophil migration in a murine model of RA by inhibiting IL-12 and IFN γ production. Methylated BSA (mBSA) and IL-23-induced neutrophil migration was inhibited by anti-IL-23 and anti-IL-17 antibodies, COX inhibitors, IL-12, or IFNγ but was enhanced by prostaglandin E2 (PGE2). IL-23-induced IL-17 production was increased by PGE2 and suppressed by COX-inhibition or IL-12. Furthermore, COX inhibition failed to reduce IL-23-induced neutrophil migration in IL-12- or IFNγ-deficient mice. IL-17-induced neutrophil migration was not affected by COX inhibitors, IL-12, or IFNγ but was inhibited by MK886 (a leukotriene synthesis inhibitor), anti-TNFα, anti-CXCL1, and anti-CXCL5 antibodies and by repertaxin (a CXCR1/2 antagonist). These treatments all inhibited mBSA- or IL-23-induced neutrophil migration. IL-17 induced neutrophil chemotaxis through a CXC chemokines-dependent pathway. Our results suggest that prostaglandin plays an important role in IL-23-induced neutrophil migration in arthritis by enhancing IL-17 synthesis and by inhibiting IL-12 and IFNγ production. We thus provide a mechanism for the pathogenic role of the IL-23/IL-17 axis in RA and also suggest an additional mechanism of action for nonsteroidal anti-inflammatory drugs.

A crucial role for TNF‐α in mediating neutrophil influx induced by endogenously generated or exogenous chemokines, KC/CXCL1 and LIX/CXCL5

Background and purpose:  Chemokines orchestrate neutrophil recruitment to inflammatory foci. In the present study, we evaluated the participation of three chemokines, KC/CXCL1, MIP‐2/CXCL2 and LIX/CXCL5, which are ligands for chemokine receptor 2 (CXCR2), in mediating neutrophil recruitment in immune inflammation induced by antigen in immunized mice.

Neutrophil recruitment in immunized mice depends on MIP-2 inducing the sequential release of MIP-1α, TNF-α and LTB4

Neutrophils are thought to play an important role in the tissue damage observed in various autoimmune diseases. Chemokines, cytokines and leukotrienes have recognized roles in the orchestration of neutrophil migration. We have recently shown that antigen‐induced neutrophil migration into the peritoneum of immunized mice is mediated by macrophage‐inflammatory protein (MIP)‐1α which interacts with CCR1 and induces the sequential release of TNF‐α and leukotriene B4 (LTB4). The present study investigates the role of MIP‐2 and CXCR2 in the cascade of events leading to mediator generation and neutrophil influx. Antigen challenge of immunized mice induced the expression of CXCR2 and the production of KC and MIP‐2 proteins. Antigen‐induced neutrophil migration was inhibited by a CXCR2 receptor antagonist (repertaxin) or an anti‐MIP‐2 antibody, but not by an anti‐KC antibody. Administration of MIP‐2 promoted a dose‐dependent neutrophil migration in naive mice which was inhibited by repertaxin, anti‐TNF‐α, anti‐MIP‐1α antibodies or by MK886 (leukotriene synthesis inhibitor). MIP‐2 administration induced the release of MIP‐1α, TNF‐α and LTB4, and the release of the latter two was inhibited by anti‐MIP‐1α antibody treatment. Our studies highlight the intricate balance between mediator production and action during an immune‐mediated inflammatory response and suggest a mediator cascade leading to neutrophil influx following antigen challenge of immunized mice: MIP‐2 → MIP‐1α → TNF‐α → LTB4.

Lercanidipine reduces matrix metalloproteinase-2 activity and reverses vascular dysfunction in renovascular hypertensive rats

Increased expression/activity of matrix metalloproteinases (MMPs), especially MMP-2, plays a role in the vascular alterations induced by hypertension, and increased oxidative stress is a major factor activating MMPs. Here, we hypothesized that lercanidipine, a calcium channel blocker, could attenuate the increases in oxidative stress and MMP-2 expression/activity in the two-kidney, one-clip (2K-1C) hypertensive rats. Sham-operated or 2K-1C hypertension rats were treated with lercanidipine 2.5 mg/kg/day (or vehicle) starting three weeks after hypertension was induced. Systolic blood pressure was monitored weekly. After five weeks of treatment, aortic rings were isolated to assess endothelium-dependent and independent relaxations. Quantitative morphometry of structural changes in the aortic wall were studied in hematoxylin/eosin sections. Aortic MMP-2 levels were determined by gelatin zymography. Aortic MMP-2/tissue inhibitor of metalloproteinases (TIMP)-2 mRNA levels were determined by quantitative real-time RT-PCR. Plasma thiobarbituric acid reactive substances concentrations were determined using a fluorometric method. Lercanidipine attenuated 2K-1C hypertension (224+/-12 versus 183+/-11 mm Hg in 2K-1C rats and 2K-1C + Lercandipine rats, respectively; P<0.01) and prevented the reduction in endothelium-dependent vasorelaxation found in 2K-1C rats. Increased MMP-2 and Pro-MMP-2 levels were found in the aortas of 2K-1C rats (all P<0.05). Lercandipine attenuated 2K-1C-induced increases in MMP-2 by more than 60% and blunted 2K-1C-induced increases in oxidative stress (both P<0.001). While hypertension-induced significant aortic wall hypertrophy and approximately 9-fold increases in the ratio of MMP-2/TIMP-2 mRNA expression (both P<0.05), lercandipine did not affect these changes. These results suggest that lercanidipine produces antihypertensive effects and reverses the endothelial dysfunction associated with 2K-1C hypertension, probably through mechanisms involving antioxidant effects leading to lower MMP-2 activation.

Detrimental role of endogenous nitric oxide in host defence against Sporothrix schenckii

We earlier demonstrated that nitric oxide (NO) is a fungicidal molecule against Sporothrix schenckii in vitro. In the present study we used mice deficient in inducible nitric oxide synthase (iNOS–/–) and C57BL/6 wild‐type (WT) mice treated with Nω‐nitro‐arginine (Nitro‐Arg‐treated mice), an NOS inhibitor, both defective in the production of reactive nitrogen intermediates, to investigate the role of endogenous NO during systemic sporotrichosis. When inoculated with yeast cells of S. schenckii, WT mice presented T‐cell suppression and high tissue fungal dissemination, succumbing to infection. Furthermore, susceptibility of mice seems to be related to apoptosis and high interleukin‐10 and tumour necrosis factor‐α production by spleen cells. In addition, fungicidal activity and NO production by interferon‐γ (IFN‐γ) and lipopolysaccharide‐activated macrophages from WT mice were abolished after fungal infection. Strikingly, iNOS–/– and Nitro‐Arg‐treated mice presented fungal resistance, controlling fungal load in tissues and restoring T‐cell activity, as well as producing high amounts of IFN‐γ Interestingly, macrophages from these groups of mice presented fungicidal activity after in vitro stimulation with higher doses of IFN‐γ. Herein, these results suggest that although NO was an essential mediator to the in vitro killing of S. schenckii by macrophages, the activation of NO system in vivo contributes to the immunosuppression and cytokine balance during early phases of infection with S. schenckii.

Lercanidipine decreases vascular matrix metalloproteinase-2 activity and protects against vascular dysfunction in diabetic rats

Abnormal matrix metalloproteinases (MMPs) activity causes cardiovascular diseases. Because hyperglycemia increase MMPs activities through increased oxidative stress, we hypothesized that antioxidant effects produced by lercanidipine could attenuate the increases in MMP-2 expression/activity in diabetic rats. Control and diabetic (alloxan-induced diabetes) rats received lercanidipine 2.5 mg/kg/day (or tap water) starting three weeks after alloxan (or vehicle) injections. Blood pressure was monitored weekly. After six weeks of treatment, vascular reactivity and structural changes were assessed in aortic rings. MMP-2 levels were determined by gelatin zymography, and MMP-2/tissue inhibitor of metalloproteinases (TIMP)-2 mRNA levels were determined by quantitative real time RT-PCR. Plasma thiobarbituric acid reactive substances concentrations were determined by fluorimetry. Lercanidipine produced antihypertensive effects (201+/-5 vs. 163+/-7 mm Hg in diabetic rats untreated and treated with lercanidipine, respectively; P<0.01) and reversed the impairment in endothelium-dependent vasorelaxation in diabetic rats. Increased MMP-2 and Pro-MMP-2 levels were found in the aortas of diabetic rats (both P<0.001). Lercandipine attenuated the increases in oxidative stress and in MMP-2 (both P<0.05). While diabetes induced no major structural changes, it caused a 16-fold increase in the ratio of MMP-2/TIMP-2 mRNA expression, which was completely reversed by lercanidipine (both P<0.001). These results show that antioxidant and beneficial vascular effects produced by lercanidipine in diabetic rats are associated with reversion of the imbalance in vascular MMP-2/TIMP-2 expression.

Matrix metalloproteinase-9 genotypes and haplotypes are associated with multiple sclerosis and with the degree of disability of the disease

Multiple sclerosis (MS) is an autoimmune disease causing severe neurological disability. This study was carried out in order to determine whether the MMP-9 C(-1562)T and (CA)(13-25) polymorphisms are associated with MS. A total of 165 patients (92 whites/73 mulattos) and 191 controls (96 whites/95 mulattos) were enrolled in the study. While no difference in C(-1562)T polymorphism was observed between MS and healthy subjects, (CA)(n) genotypes and alleles were associated with MS. Moreover, the haplotypes are not associated with MS but seem to be relevant to the clinical status of MS. Thus the (CA)(n) polymorphism may contribute to MS susceptibility, but C(-1562)T and (CA)(n) haplotypes may modulate disease severity.

Functional polymorphism located in MMP-9 gene promoter is strongly associated with obesity.

The adipose tissue expansion is accompanied by remodeling of extracellular matrix performed by matrix metalloproteinases (MMPs). Higher plasma and tissue MMP-9 levels are found in obese; therefore, we evaluated if the functional C(-1562)T polymorphism (rs3918242) located in promoter region of the MMP-9 gene is associated with obesity in women. We studied 112 lean and 114 obese women. Plasma MMP-9 and tissue inhibitor of MMP-9 (TIMP)-1 were measured using enzyme-linked immunosorbent assay. We found different genotype frequencies between lean and obese women (p=0.008), prevailing T-allele in obese (2.3-fold). However, although obese women present higher levels of plasma MMP-9, lack of modulation by the polymorphism was found (all p>0.05). Our findings suggest that C(-1562)T polymorphism may contribute to pathogenetic mechanisms involved in the development of obesity in women.

Functional MMP-9 polymorphisms modulate plasma MMP-9 levels in multiple sclerosis patients.

We have described that MMP-9 C(-1562)T and (CA)(n) polymorphisms contribute to multiple sclerosis (MS). Here, we evaluate whether plasma MMP-9 levels are related to disease severity, drug therapy resistance and polymorphisms. For sub-study 1, 36 patients with MS and 35 controls were recruited. For sub-study 2, 88 individuals (53 patients and 35 controls) were included in a cross-sectional analysis. MS patients presented higher MMP-9 activity (1.4±0.18 versus 0.93±0.18A.U. for control, P<0.05). Drug-therapy resistant individuals exhibited increased MMP-9 activity (1.96±0.25 versus 1.21±0.09A.U. for non-resistant patients). EDSS score was also related to MMP-9 levels. The CT+TT and HH genotypes had higher MMP-9 levels as compared to patients carrying the CC and LL. Drug therapy resistance, disease severity, MMP-9 plasma activity and polymorphisms are associated with MS.

Plasma levels of increased miR-195-5p correlates with the sFLT-1 levels in preeclampsia.

ABSTRACT Although the role of soluble fms-like tyrosine kinase 1 (sFLT-1) in preeclampsia is well-established, the mechanism related to its synthesis remains poorly understood. We evaluated the association among the circulating microRNAs (miRs) and sFLT-1 levels in preeclampsia pregnant women. For this purpose, we measured the plasma sFLT-1 levels in 24 preeclampsia women and selected from these, three subjects with the lowest and three with the highest levels of sFLT-1 in order to screen for potential miRs associated with plasmatic sFLT-1 concentrations using a polymerase chain reaction-array (PCR-array) methodology. From screening results, we found three statistically different expressed miRs with fold change (FC-high/low levels) ≥3.0: miR-195-5p (FC = 5.2 increase in group with high sFLT-1 levels), miR-16-5p (FC = 3.2; increase in group with high sFLT-1 levels), and miR-375 (FC = −3.0; decrease in group with high sFLT-1 levels) which were later validated in all samples (n = 24). To correlate these miRs and plasma sFLT-1 levels, we used two extremes of analysis. In one part, we compared 12 preeclampsia women with the lowest sFLT-1 levels (L-50% group) to 12 with the highest levels (50% H group); and in the second analysis, 6 preeclampsia women (L-25%) from the L group to 6 preeclampsia women from the H group (H-25%). Our results showed increased expression of miR-195-5p in the H group, considering both the analyses with 50%, FC = 2.1 and 25%, FC = 4.2. Regarding other miRs, lack of correlation was found in both analyses (50% and 25%). In conclusion, our data demonstrate an association of higher levels of sFLT-1 with increased expression of miR-195-5p in preeclampsia pregnant women.