Upregulation of pro-inflammatory cytokines in the intercostal muscles of COPD patients

Muscle dysfunction is a characteristic feature of chronic obstructive pulmonary disease (COPD). Recent studies suggest that cytokines may operate as local regulators of both muscle function and regeneration. The aim of the present study was to characterise the expression of different cytokines in the external intercostal muscle of COPD. Muscle biopsies were obtained from 25 stable COPD patients and eight healthy controls. Local tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, -6 and -10 expressions (real-time PCR and ELISA), sarcolemmal damage (immunohistochemistry), and the transcript levels of CD18 were assessed. Muscle TNF-alpha and IL-6 transcripts were significantly higher in COPD patients compared with controls, and IL-1beta and sarcolemmal damage showed a strong tendency in the same direction. Similar results were observed at protein level. The CD18 panleukocyte marker was similar in COPD and controls. Respiratory muscle function was impaired in COPD patients and it correlated to both the severity of lung function impairment and TNF-alpha muscle expression. Chronic obstructive pulmonary disease is associated with the upregulation of pro-inflammatory cytokines in the intercostal muscles. This phenomenon might be involved in respiratory muscle dysfunction.

Analysis of Respiratory Muscle Structure and Tumor Necrosis and Insulin-Like Growth Factor Expression in Chronic Obstructive Pulmonary Disease: Are Samples Valid if Obtained During Thoracotomy Performed Because of Localized Pulmonary Neoplasia?

OBJECTIVE

Various methods have been used to obtain samples to study the structure of human respiratory muscles and the expression of diverse substances in them. Samples are most often obtained from autopsies, from muscle biopsies during thoracotomy performed because of a localized pulmonary lesion (TLL), and from ambulatory thoracoscopic biopsy in patients free of comorbidity (AT). The disadvantage of the first 2 of these methods lies in the possibility of interference from factors related to the patient's death in the first case or from the disease that necessitated surgery in the second. Although AT is free from the disadvantages of the other 2 methods, it is impossible to obtain samples of the diaphragm the principal respiratory muscle with this procedure. The objective of this study was to analyze the fibrous structure of the external intercostal muscle of patients with chronic obstructive pulmonary disease and to quantify the expression of the principal inflammatory cytokine tumor necrosis factor alpha (TNF-alpha)- and of insulin-like growth factor (IGF-1) in the same muscle, comparing the results obtained with TLL and AT samples.

METHODS

Prospective and consecutive samples were taken of the external intercostal muscle (fifth space, anterior axillary line) in 15 patients with chronic obstructive pulmonary disease (mean [SD] age 66 [6] years; forced expiratory volume in 1 second 49% [9%] of predicted; PaO2 75 [9] mm Hg). Samples were taken during TLL (8 patients, all with pulmonary neoplasms but carefully selected in order to rule out systemic effects) or TA (7 patients). Patients with serious comorbidity were excluded from the second group. Samples were processed for structural analysis of fibers (immunohistochemical and enzymatic histochemical) and genetic expression of TNF-alpha and IGF-1 (real-time polymerase chain reaction).

RESULTS

No differences in the structure of fibers were found between the 2 groups. No differences were observed in the expression of TNF-alpha or IGF-1.

CONCLUSIONS

Using rigorous criteria, the TLL method appears to be suitable for studying the structural characteristics and expression of inflammatory cytokines and growth factors in the external intercostal muscle. Moreover, it can also be inferred that TLL is probably also useful for obtaining samples of the diaphragm, a muscle which cannot currently be sampled by any alternative method.

DNA hypermethylation at the D17S5 locus is not a frequent event in human urothelial cancer

OBJECTIVE

To analyse the DNA methylation status and the loss of heterozygosity (LOH) at the D17S5 locus (17p13.3) in urothelial cancer.

MATERIALS AND METHODS

DNA methylation was assayed and LOH analysed by Southern blotting in a series of 33 transitional cell carcinomas of the bladder and renal pelvis.

RESULTS

DNA hypermethylation and LOH at the D17S5 locus were detected in six (18%) and 17 (52%) of the tumours, respectively. The six cases with DNA hypermethylation were of the papillary type, and four also had LOH at this locus.

CONCLUSION

In contrast to other epithelial tumours, DNA hypermethylation at the D17S5 locus is not a frequent event in human urothelial cancer.

[Interleukin 10 and tumor necrosis factor alpha gene expression in respiratory and peripheral muscles. Relation to sarcolemmal damage]

BACKGROUND

Tumor necrosis factor alpha (TNF-alpha) has been implicated in loss of muscle mass in chronic obstructive pulmonary disease and other consumptive processes. TNF-alpha production would be related to inflammation arising from pulmonary disease itself or, alternatively, from smoking, and would be carried to the muscle through the blood stream. However, it has also been suggested that TNF-alpha may be expressed directly in muscle tissue. Regardless the site of production of TNF-alpha, its relation to subsequent muscle damage is unclear.

OBJECTIVE

We studied the expression of TNF-alpha and an interleukin inhibitor of its production (IL-10) in the main respiratory muscles and a peripheral muscle in the dog.

METHOD

Nine young, male Beagle dogs were included. From all animals we obtained a biopsy of the diaphragm (Dph) and external intercostal (ExtI) muscles and a leg muscle (internal vastus of the quadriceps, IntV). TNF-alpha and IL-10 gene expressions were measured through the analysis of messenger RNA levels, using reverse transcription and polymerase chain reaction. We also assessed sarcolemmal damage using intracellular fibronectin detection (immunohistochemistry).

RESULTS

The expression of both cytokines showed wide interindividual variability. On the one hand, TNF-alpha (was very low in Dph and ExtI (0.02 0.03 and 0.05 0.06 a.u., respectively), but relatively high in the IntV (0.14 0.08 a.u.). IL-10 expression, on the other hand was low in the Dph (0.06 0.05 a.u.) and slightly higher in the ExtI (2.7 1.9 a.u., p < 0.01) and IntV (1.6 1.7 a.u.). Sarcolemmal damage was minimal in all three muscles and was related to TNF-alpha expression in the peripheral muscle (r = 0.682, p < 0.05).

CONCLUSIONS

1) TNF-alpha and IL-10 appear to be constitutively expressed within the skeletal muscle in dogs. 2) Basal TNF-alpha expression is lower in respiratory muscles than in peripheral muscles. 3) The expression in the latter is related to membrane damage.

Comparative genomic hybridization analysis of transitional cell carcinomas of the renal pelvis

We used comparative genomic hybridization to analyze 10 primary tumor samples from patients with transitional cell carcinoma of the renal pelvis. The most frequent loss was located at 9q, that is, in 50% of the tumors. Gains of DNA sequences were most frequently observed in chromosome regions 1q21 approximately q23, 2p23 approximately p25, 8q21.1 approximately q22 and in the whole chromosome 20. High level amplifications at 1q21 approximately q25, 6p22 approximately p23, 8q21 approximately q22, 8q22 approximately q24.1, 11q13, and 12q14 approximately q21 were detected. Most of these regions have previously been reported to be involved in transitional cell carcinoma of the bladder, thus confirming the importance of an increasing number of chromosome imbalances in the development and progression of this type of tumors.

Study of allelic losses on 3p, 6q, and 17p in human urothelial cancer

Forty-eight transitional cell carcinomas of the bladder and three transitional cell carcinomas of the renal pelvis were examined for loss of heterozygosity (LOH) on chromosomes 3p, 6q, and 17p. The most frequent allelic loss was seen on 17p (18/36, 50%) followed by 6q (6/22, 27%), and 3p (5/22, 23%). In cases with LOH at more than one locus, the same DNA sample often varied in degree of signal reduction for missing alleles. This observation indicates that LOH studies can serve to detect intratumor heterogeneity. No correlation was found between allelic losses at these chromosome arms and tumor grade and stage. Allelic losses on 6q were associated with tumors having a solid growth pattern; in this kind of tumors, allelic losses on 3p were associated with invasion.

Analysis of 3p allelic losses in renal cell carcinomas: comparison with cytogenetic results

We performed a study of loss of heterozygosity (LOH) at 3p by restriction fragment length polymorphism analysis in a series of 22 renal tumors. In 11 cases, molecular results could be compared with those of cytogenetic studies. The highest frequency of allelic losses at 3p was seen in clear cell non-papillary renal tumors, whereas none of the papillary renal cell carcinomas showed LOH at 3p. Allelic losses on 3p were found to be independent of tumor grade or stage or both. One case analyzed showed a discrepancy between cytogenetic and LOH studies. This tumor displayed rearrangements of chromosome 3 and no LOH at the c-RAF-1 (close to the Von Hippel Lindau gene) locus.

Germline and somatic mutations in the tyrosine kinase domain of the MET proto-oncogene in papillary renal carcinomas

Hereditary papillary renal carcinoma (HPRC) is a recently recognized form of inherited kidney cancer characterized by a predisposition to develop multiple, bilateral papillary renal tumours. The pattern of inheritance of HPRC is consistent with autosomal dominant transmission with reduced penetrance. HPRC is histologically and genetically distinct from two other causes of inherited renal carcinoma, von Hippel-Lindau disease (VHL) and the chromosome translocation (3;8). Malignant papillary renal carcinomas are characterized by trisomy of chromosomes 7, 16 and 17, and in men, by loss of the Y chromosome. Inherited and sporadic clear cell renal carcinomas are characterized by inactivation of both copies of the VHL gene by mutation, and/or by hypermethylation. We found that the HPRC gene was located at chromosome 7q31.1-34 in a 27-centimorgan (cM) interval between D7S496 and D7S1837. We identified missense mutations located in the tyrosine kinase domain of the MET gene in the germline of affected members of HPRC families and in a subset of sporadic papillary renal carcinomas. Three mutations in the MET gene are located in codons that are homologous to those in c-kit and RET, proto-oncogenes that are targets of naturally-occurring mutations. The results suggest that missense mutations located in the MET proto-oncogene lead to constitutive activation of the MET protein and papillary renal carcinomas.

Cytogenetic characterization of a familial papillary renal cell carcinoma

We describe the first case of a familial renal cell carcinoma cytogenetically characterized as a papillary renal cell carcinoma. Cytogenetic and molecular studies were performed on primary renal cell carcinomas and normal kidney tissue from two members of the same family. Both patients showed a normal constitutional karyotype. The two tumors analyzed from the first patient showed the numerical chromosome alterations characteristic of papillary renal cell carcinomas. From the four tumors analyzed in the second patient, three of them presented the cytogenetic pattern of papillary renal cell tumors, and the fourth showed only structural chromosome abnormalities with the presence of a del(7)t(7;7) or dup(7) in all metaphases analyzed. Chromosome 3 was cytogenetically unaffected in all tumors from both patients, and restriction fragment length polymorphism analysis performed with probe pEFD145 (3p21.1-p23) did not detect any loss of heterozygosity.

A case of transitional cell carcinoma of the bladder with a del(9)(q11q21.2)

Monosomy for chromosome 9, as well as loss of heterozygosity for markers on this chromosome, has been detected in a high percentage of transitional cell carcinomas (TCC) of the bladder. We report a case of a TCC of the bladder with an interstitial del(9)(q11q21.2) that could be indicative of the presence of a putative tumor-suppressor gene related to bladder tumor progression. To elucidate the role of chromosome 9 in bladder tumors, it would be interesting to study a possible loss of heterozygosity in this chromosome region.

The Jun family members, c-Jun and JunD, transactivate the human c-myb promoter via an Ap1-like element

The c-myb protooncogene, which is preferentially expressed in hematopoietic cells at the G1/S boundary of the cell cycle, encodes a transcriptional activator that functions via DNA binding. The regulatory mechanisms governing this specific pattern of expression are not fully understood, although human c-myb expression appears to be positively autoregulated via myb-binding sites in the 5'-flanking region of the c-myb gene (Nicolaides, N. C., Gualdi, R., Casadevall, C., Manzella, L., and Calabretta, B. (1991) Mol. Cell. Biol. 11, 6166-6176). To determine the contribution of other transcription regulators such as JUN family members in the control of c-myb expression, transient expression assays were carried out which revealed a 6- to a 15-fold enhancement by c-Jun and JunD, but not JunB, in chloramphenicol acetyltransferase reporter gene expression driven by different segments of the human c-myb 5'-flanking region. An Ap1-like element located at nucleotide -149 from the c-myb initiation site appears to be required for this transactivation upon binding to a nuclear protein complex containing c-Jun and JunD, since site-directed mutations of this Ap1-like element abolished c-Jun and JunD binding and transactivation. Exposure of phytohemagglutinin-stimulated peripheral blood mononuclear cells to c-jun and junD antisense oligodeoxynucleotides resulted in a 46 and 43% inhibition of T-lymphocyte proliferation that was accompanied by a decrease in c-myb mRNA levels as compared with sense-treated cultures. Because T-lymphocytes induced to proliferate express c-jun and junD before c-myb, these data suggest a mechanism whereby c-Jun and JunD contribute to the transcriptional activation of c-myb that, in turn, is maintained at the G1/S transition and during S phase by positive autoregulation.

Positive autoregulation of c-myb expression via Myb binding sites in the 5' flanking region of the human c-myb gene

The nuclear proto-oncogene c-myb is preferentially expressed in lymphohematopoietic cells, in which it plays an important role in the processes of differentiation and proliferation. The mechanism(s) that regulates c-myb expression is not fully understood, although in mouse cells a regulatory mechanism involves a transcriptional block in the first intron. To analyze the contribution of the 5' flanking sequences in regulating the expression of the human c-myb gene, we isolated a genomic clone containing extensive 5' flanking sequences, the first exon, and a large portion of the first intron. Sequence analysis of a subcloned 1.3-kb BamHI insert corresponding to 687 nucleotides of the 5' flanking sequence, the entire first exon, and 300 nucleotides of the first intron revealed the presence of closely spaced putative Myb binding sites within a segment extending from nucleotides -616 to -575 upstream from the cap site. A 165-bp segment containing these putative Myb binding sites was linked to a human thymidine kinase (TK) cDNA driven by a low-activity proliferating cell nuclear antigen promoter and cotransfected into TK- ts13 cells with a plasmid in which a full-length human c-myb cDNA is driven by the early simian virus 40 promoter; Myb inducibility of TK mRNA expression was observed both in transient expression assays and in stable transformants. The highest level of inducibility was detected when the 165-bp fragment was placed 138 bp upstream of the proliferating cell nuclear antigen promoter-TK cDNA reporter unit or 3' of the TK cDNA. Mutation of the putative Myb binding sites greatly reduced c-myb transactivation of TK mRNA expression and specifically reduced the binding of in vitro-translated Myb protein at those sites. Finally, c-myb transactivated TK mRNA expression driven by a segment of the authentic c-myb 5' flanking region containing the Myb binding sites. These data suggest that human c-myb maintains high levels of Myb protein in cells that require this gene product for proliferation and/or differentiation by an autoregulatory mechanism involving Myb binding sites in the 5' flanking region.

Importance of introns in the growth regulation of mRNA levels of the proliferating cell nuclear antigen gene

The steady-state mRNA levels of the proliferating cell nuclear antigen (PCNA) gene are growth regulated. We have begun to identify the elements in the human PCNA gene that participate in its growth regulation by transfecting appropriate constructs in BALB/c3T3 cells. The results can be summarized as follows. (i) The 400 base pairs of the 5'-flanking sequence of the human PCNA gene upstream of the preferred cap site are sufficient for directing expression of a heterologous cDNA (S. Travali, D.-H. Ku, M. G. Rizzo, L. Ottavio, R. Baserga, and B. Calabretta, J. Biol. Chem. 264:7466-7472, 1989). (ii) Intron 4 is necessary for the proper regulation of PCNA mRNA levels in G0 cells. Removal of intron 4 leads to abnormally high levels of PCNA mRNA in serum-deprived cells, although the shortened PCNA gene with its own promoter is still responsive to serum stimulation. (iii) The presence of introns also increases the steady-state levels of PCNA mRNA in proliferating cells. These results are especially interesting for two reasons: (i) because of the extensive sequence similarities among introns and between introns and exons of the human PCNA gene, and (ii) because, usually, the presence of introns leads to increased expression, whereas in this case, removal of intron 4 caused an increase in mRNA levels, and this occurred only in quiescent cells.

Contribution of the guanosinetriphosphatase activity of G-protein to termination of light-activated guanosine cyclic 3',5'-phosphate hydrolysis in retinal rod outer segments

Light activation of GTP binding to G-protein and its eventual hydrolysis are hypothesized to lead to activation and inactivation of cGMP phosphodiesterase (PDE) in vertebrate rod disk membranes (RDM). However, the reported GTPase rate of 3 per minute is too slow to account for the observed rapid inactivation of PDE. Our investigations on GTPase activity showed that RDM isolated in the dark have considerable dark GTPase activity, which is enhanced by light. In dark and light, the enzyme exhibits biphasic substrate dependence with two Km's for GTP of 2-3 and 40-80 microM at 22 degrees C and less than 1 and 10-25 microM at 37 degrees C. The Km's were not influenced by light. On the basis of G-protein content of the RDM, the Vmax's for the two activities at 37 degrees C in light are 4-5 and 20-30 GTPs hydrolyzed per minute per G-protein. RDM washed free of soluble and peripheral proteins do not have measurable GTPase activity in the dark or light. Purified G-protein alone also did not turn over GTP, apparently because bleached rhodopsin is required for it to bind GTP. Reconstitution of washed membranes with purified G-protein restores both the low- and high-Km GTPase activities. Inactivation of G-protein as measured by PDE turnoff and dissociation signal recovery is found to be faster at higher than lower [GTP], consistent with the observation that the higher GTPase activity associated with the higher Km alos resides in the G-protein.(ABSTRACT TRUNCATED AT 250 WORDS)