Multidrug resistance-associated protein-1 (MRP1) genetic variants,MRP1 protein levels and severity of COPD

Background

Multidrug resistance-associated protein-1 (MRP1) protects against oxidative stress and toxic compounds generated by cigarette smoking, which is the main risk factor for chronic obstructive pulmonary disease (COPD). We have previously shown that single nucleotide polymorphisms (SNPs) in MRP1 significantly associate with level of FEV₁ in two independent population based cohorts. The aim of our study was to assess the associations of MRP1 SNPs with FEV₁ level, MRP1 protein levels and inflammatory markers in bronchial biopsies and sputum of COPD patients.

Methods

Five SNPs (rs212093, rs4148382, rs504348, rs4781699, rs35621) in MRP1 were genotyped in 110 COPD patients. The effects of MRP1 SNPs were analyzed using linear regression models.

Results

One SNP, rs212093 was significantly associated with a higher FEV₁ level and less airway wall inflammation. Another SNP, rs4148382 was significantly associated with a lower FEV₁ level, higher number of inflammatory cells in induced sputum and with a higher MRP1 protein level in bronchial biopsies.

Conclusions

This is the first study linking MRP1 SNPs with lung function and inflammatory markers in COPD patients, suggesting a role of MRP1 SNPs in the severity of COPD in addition to their association with MRP1 protein level in bronchial biopsies.     

Sialic acid attenuates puromycin aminonucleoside-induced desialylation and oxidative stress in human podocytes

Sialoglycoproteins make a significant contribution to the negative charge of the glomerular anionic glycocalyx—crucial for efficient functioning of the glomerular permselective barrier. Defects in sialylation have serious consequences on podocyte function leading to the development of proteinuria. The aim of the current study was to investigate potential mechanisms underlying puromycin aminonucleosisde (PAN)-induced desialylation and to ascertain whether they could be corrected by administration of free sialic acid.     

The effect of albumin on podocytes: The role of the fatty acid moiety and the potential role of CD36 scavenger receptor

Evidence is emerging that podocytes are able to endocytose proteins such as albumin using kinetics consistent with a receptor-mediated process. To date the role of the fatty acid moiety on albumin uptake kinetics has not been delineated and the receptor responsible for uptake is yet to be identified.     

Pharmacological enhancement of the kallikrein-kinin system promotes anti-fibrotic responses in human mesangial cells.

The aim of the present study was to investigate whether pharmacological enhancement of the renal kallikrein-kinin system using the vasopeptidase inhibitor omapatrilat plays a direct role in modulating the fibrotic responses of human mesangial cells to injury. Treatment with 40 micromol/L omapatrilat was able to reduce macrophage-conditioned medium (MPCM)-induced fibronectin levels without affecting mRNA expression. MPCM injury also suppressed kallikrein and low molecular weight kininogen mRNA. Omapatrilat was able to attenuate this suppression. Bradykinin levels in contrast were increased by MPCM and treatment with omapatrilat further augmented levels. Co-incubation with the bradykinin B2 receptor antagonist HOE 140 attenuated the omapatrilat-induced lowering of fibronectin. Moreover, inhibition of cGMP release had a similar effect. Paradoxically, RT-PCR and Southern blotting demonstrated that bradykinin B2 receptor mRNA levels were down regulated in response to omapatrilat. Western blotting supported this data. Supernatant levels of tissue plasminogen activator (tPA), a product of bradykinin stimulation, were decreased by omapatrilat while cell associated tPA levels were increased. Matrix metalloproteinase-9 (MMP-9) mRNA expression was up regulated by omapatrilat treatment, although no difference in active zymogen levels was observed. In conclusion enhancement of kallikrein-kinin system appears to play a direct role in promoting anti-fibrotic responses in MPCM-injured human mesangial cells.     

Smoking status and anti-inflammatory macrophages in bronchoalveolar lavage and induced sputum in COPD

Background

Macrophages have been implicated in the pathogenesis of COPD. M1 and M2 macrophages constitute subpopulations displaying pro- and anti-inflammatory properties. We hypothesized that smoking cessation affects macrophage heterogeneity in the lung of patients with COPD. Our aim was to study macrophage heterogeneity using the M2-marker CD163 and selected pro- and anti-inflammatory mediators in bronchoalveolar lavage (BAL) fluid and induced sputum from current smokers and ex-smokers with COPD.

Methods

114 COPD patients (72 current smokers; 42 ex-smokers, median smoking cessation 3.5 years) were studied cross-sectionally and underwent sputum induction (M/F 99/15, age 62 ± 8 [mean ± SD] years, 42 (31-55) [median (range)] packyears, post-bronchodilator FEV₁ 63 ± 9% predicted, no steroids past 6 months). BAL was collected from 71 patients. CD163⁺ macrophages were quantified in BAL and sputum cytospins. Pro- and anti-inflammatory mediators were measured in BAL and sputum supernatants.

Results

Ex-smokers with COPD had a higher percentage, but lower number of CD163⁺ macrophages in BAL than current smokers (83.5% and 68.0%, p = 0.04; 5.6 and 20.1 ×10⁴/ml, p = 0.001 respectively). The percentage CD163⁺ M2 macrophages was higher in BAL compared to sputum (74.0% and 30.3%, p < 0.001). BAL M-CSF levels were higher in smokers than ex-smokers (571 pg/ml and 150 pg/ml, p = 0.001) and correlated with the number of CD163⁺ BAL macrophages (Rs = 0.38, p = 0.003). No significant differences were found between smokers and ex-smokers in the levels of pro-inflammatory (IL-6 and IL-8), and anti-inflammatory (elafin, and Secretory Leukocyte Protease Inhibitor [SLPI]) mediators in BAL and sputum.

Conclusions

Our data suggest that smoking cessation partially changes the macrophage polarization in vivo in the periphery of the lung towards an anti-inflammatory phenotype, which is not accompanied by a decrease in inflammatory parameters.     

Mapping of monoclonal antibody-defined epitopes associated with carcinoembryonic antigen,CEA

Summary Six immunoglobulin G monoclonal antibodies reactive with carcinoembryonic antigen (CEA) were evaluated with respect to parameters implicated in their potential diagnostic application and use as tumor targeting agents for cytotoxic drugs or plant or bacterial toxins. Antibody reactivity with surface antigens of the MKN-45 gastric tumor cell line was demonstrated by flow cytofluorimetry. In a subcellular membrane binding assay, each antibody reacted preferentially with membranes isolated from colorectal tumor tissue in comparison with their reaction with membranes from adjacent, apparently normal colonic mucosa. Three of the antibodies (NCRC-23, C228, and 11.285.14) reacted specifically with CEA with little or no reaction with the cross-reacting antigen, NCA. The remaining three antibodies (C24, C161, and C198) were reactive with both CEA and NCA. Analysis of the epitopes defined by these antibodies was performed by competitive binding inhibition assays evaluating the capacity of unlabeled antibodies to compete with ¹²⁵I-labeled antibodies in their binding to CEA. In addition, double determinant or sandwich radioimmunoassays were employed to examine the coexpression of epitopes on CEA molecules. These studies permitted an epitope map to be constructed which describes the coincidence, overlapping, or independent expression of both CEA specific epitopes and epitopes shared between CEA and NCA. The map may be employed for the selection of antibodies for diagnostic and therapeutic use.     

Sexual differences in caudal morphology and its relation to tail autotomy in lacertid lizards

We hypothesized that the presence of the forked hemipenes, and associated musculature, at the base of the tail in male lizards should constrain the capacity to autotomize the tail. Thus, this hypothesis predicts that the non-autotomous base of the tail should be longer in male than in female lizards. We tested this hypothesis in four species oflacertid lizards. Males have on average one to two non-autotomous vertebrae more than females, and the sexual difference in length of the non-autotomous tail base remains constant over the entire body size range. In addition, the first functional autotomy plane in males is usually located on, or is distal to, the vertebrae from which two hemipenial muscles take origin. These observations support the view that functional demands of the male intromittent organs impose constraints on the abilities of tail autotomy. In a natural population of Lacerta vivipara , the proportion of tail breaks that occurred at very short distances from the base was highest in females, indicating that the small sexual difference in length of the non-autotomous tail part is of functional significance. Total length of the tail was largest in males. This can be interpreted as a compensation for the decline in autotomy capacities at the tail base, such that the length of the autotomous part remains similar in both sexes.     

Nonpeptide oxytocin antagonists: analogs of L-371,257 with improved potency.

Structure-activity studies on the oxytocin antagonist 1 (L-371,257; Ki = 9.3 nM) have led to the identification of a related series of compounds containing an ortho-trifluoroethoxyphenylacetyl core which are orally bioavailable and have significantly improved potency in vitro and in vivo, e.g., compound 8 (L-374,943; Ki = 1.4 nM).