Atp6i-deficient mice exhibit severe osteopetrosis due to loss of osteoclast-mediated extracellular acidification

Solubilization of bone mineral by osteoclasts depends on the formation of an acidic extracellular compartment through the action of a V-proton pump that has not yet been characterized at the molecular level. We previously cloned a gene (Atp6i, for V-proton pump, H+ transporting (vacuolar proton pump) member I) encoding a putative osteoclast-specific proton pump subunit, termed OC-116kD (ref. 4). Here we show that targeted disruption of Atp6i in mice results in severe osteopetrosis. Atp6i-/- osteoclast-like cells (OCLs) lose the function of extracellular acidification, but retain intracellular lysosomal proton pump activity. The pH in Atp6i-/- liver lysosomes and proton transport in microsomes of Atp6i-/- kidney are identical to that in wild-type mice. Atp6i-/- mice exhibit a normal acid-base balance in blood and urine. Our results demonstrate that Atp6i is unique and necessary for osteoclast-mediated extracellular acidification.

Tumor necrosis factor-alpha and muscle wasting: a cellular perspective

Tumor necrosis factor-alpha (TNF-alpha) is a polypeptide cytokine that has been associated with muscle wasting and weakness in inflammatory disease. Despite its potential importance in muscle pathology, the direct effects of TNF-alpha on skeletal muscle have remained undefined until recently. Studies of cultured muscle cells indicate that TNF-alpha disrupts the differentiation process and can promote catabolism in mature cells. The latter response appears to be mediated by reactive oxygen species and nuclear factor-kappaB which upregulate ubiquitin/proteasome activity. This commentary outlines our current understanding of TNF-alpha effects on skeletal muscle and the mechanism of TNF-alpha action.

NF-kappaB mediates the protein loss induced by TNF-alpha in differentiated skeletal muscle myotubes

Nuclear factor-kappaB (NF-kappaB) regulates the transcription of a variety of genes involved in immune responses, cell growth, and cell death. However, the role of NF-kappaB in muscle biology is poorly understood. We recently reported that tumor necrosis factor-alpha (TNF-alpha) rapidly activates NF-kappaB in differentiated skeletal muscle myotubes and that TNF-alpha acts directly on the muscle cell to induce protein degradation. In the present study, we ask whether NF-kappaB mediates the protein loss induced by TNF-alpha. We addressed this problem by creating stable, transdominant negative muscle cell lines. C2C12 myoblasts were transfected with viral plasmid constructs that induce overexpression of mutant I-kappaBalpha proteins that are insensitive to degradation via the ubiquitin-proteasome pathway. These mutant proteins selectively inhibit NF-kappaB activation. We found that differentiated myotubes transfected with the empty viral vector (controls) underwent a drop in total protein content and in fast-type myosin heavy-chain content during 72 h of exposure to TNF-alpha. In contrast, total protein and fast-type myosin heavy-chain levels were unaltered by TNF-alpha in the transdominant negative cell lines. TNF-alpha did not induce apoptosis in any cell line, as assessed by DNA ladder and annexin V assays. These data indicate that NF-kappaB is an essential mediator of TNF-alpha-induced catabolism in differentiated muscle cells.

MicroRNA-497 targets insulin-like growth factor 1 receptor and has a tumour suppressive role in human colorectal cancer

Past studies have shown that amplified insulin-like growth factor 1 (IGF1)/IGF1 receptor (IGF1-R) signalling has an important role in colorectal cancer (CRC) development, progression and resistance to treatment. In this report, we demonstrate that downregulation of microRNA-497 (miR-497) as a result of DNA copy number reduction is involved in upregulation of IGF1-R in CRC cells. MiR-497 and miR-195 of the miR-15/16/195/424/497 family that share the same 3′ untranslated region (3′UTR) binding seed sequence and are predicted to target IGF1-R were concurrently downregulated in the majority of CRC tissues relative to paired adjacent normal mucosa. However, only overexpression of miR-497 led to suppression of the IGF1-R 3′UTR activity and downregulation of the endogenous IGF1-R protein in CRC cells. This was associated with inhibition of cell survival, proliferation and invasion, and increased sensitivity to apoptosis induced by various stimuli including the chemotherapeutic drugs cisplatin and 5-fluorouracil, and the death ligand tumour necrosis factor-related apoptosis-inducing ligand. The biological effect of miR-497 on CRC cells was largely mediated by inhibition of phosphatidylinositol 3-kinase/Akt signalling, as overexpression of an active form of Akt reversed its impact on cell survival and proliferation, recapitulating the effect of overexpression of IGF1-R. Downregulation of miR-497 and miR-195 appeared to associate with copy number loss of a segment of chromosome 17p13.1, where these miRs are located at proximity. Similarly to miR-195, the members of the same miR family, miR-424 that was upregulated, and miR-15a, miR-15b and miR-16 that were unaltered in expression in CRC tissues compared with paired adjacent normal mucosa, did not appear to have a role in regulating the expression of IGF1-R. Taken together, these results identify downregulation of miR-497 as an important mechanism of upregulation of IGF1-R in CRC cells that contributes to malignancy of CRC.

Two epithelial tumor cell lines (HNE-1 and HONE-1) latently infected with Epstein-Barr virus that were derived from nasopharyngeal carcinomas

Two epithelial tumor cell lines were established from biopsy specimens of nasopharyngeal carcinomas (NPC). The specimens were taken from poorly differentiated squamous cell carcinomas of the nasopharynx. The tissues were prepared for cell culture and eventually two continuous epithelial cell lines were obtained and designated HONE-1 and HNE-1. Light and electron microscopic examination of these two cell lines demonstrated cells with an epithelial morphology including the presence of desmosomes. The HNE-1 cell line has been passaged more than 100 times and the HONE-1 cell line has been passaged more than 90 times. It was found that early-passage uncloned HNE-1 cells (passage 23) could be superinfected with the B95-8 and NPC-EBV isolates as demonstrated by the induction of Epstein-Barr virus (EBV)-specific early antigen(s) in a small percentage of the cells; HONE-1 cells could also be superinfected with EBV. Southern blot analysis detected EBV DNA in samples from uncloned HNE-1 cells at passages 12, 17, 21, 27, and 35. However, by passage 45, EBV DNA could no longer be detected in HNE-1 cells by Southern blot analysis. The EBV genome was detected in parental HONE-1 cells at subculture 9 and in clone 40 cells up to passage 40 thus far. When HNE-1 cells were examined for the expression of the EBV-encoded nuclear antigen (EBNA) at passage 12, only about 10% of the cells were found to be positive. The percentage of EBNA-positive HNE-1 cells decreased as the cells were passaged. A similar loss of EBNA was observed in uncloned HONE-1 cells, but not in HONE-1 clone 40 cells. In clone 40, which has been passaged 40 times thus far, 85-90% of the cells are still EBNA-positive. The data suggest that EBV genome-positive HNE-1 and HONE-1 cells were lost as the cells were cultivated in vitro and that cloning the cells at an early passage level may be critical in maintaining EBV genome-positive epithelial NPC cells. These EBV genome-positive epithelial NPC cell lines will be useful for studying the association of EBV and NPC.

Skeletal muscle myocytes undergo protein loss and reactive oxygen-mediated NF-kappaB activation in response to tumor necrosis factor alpha

Skeletal muscle atrophy and weakness are thought to be stimulated by tumor necrosis factor alpha (TNF-alpha) in a variety of chronic diseases. However, little is known about the direct effects of TNF-alpha on differentiated skeletal muscle cells or the signaling mechanisms involved. We have tested the effects of TNF-alpha on the mouse-derived C2C12 muscle cell line and on primary cultures from rat skeletal muscle. TNF-alpha treatment of differentiated myotubes stimulated time- and concentration-dependent reductions in total protein content and loss of adult myosin heavy chain (MHCf) content; these changes were evident at low TNF-alpha concentrations (1-3 ng/ml) that did not alter muscle DNA content and were not associated with a decrease in MHCf synthesis. TNF-alpha activated binding of nuclear factor kappaB (NF-kappaB) to its targeted DNA sequence and stimulated degradation of I-kappaBalpha, an NF-kappaB inhibitory protein. TNF-alpha stimulated total ubiquitin conjugation whereas a 26S proteasome inhibitor (MG132 10-40 microM) blocked TNF-alpha activation of NF-kappaB. Catalase 1 kU/ml inhibited NF-kappaB activation by TNF-alpha; exogenous hydrogen peroxide 200 microM activated NF-kappaB and stimulated I-kappaBalpha degradation. These data demonstrate that TNF-alpha directly induces skeletal muscle protein loss, that NF-kappaB is rapidly activated by TNF-alpha in differentiated skeletal muscle cells, and that TNF-alpha/NF-kappaB signaling in skeletal muscle is regulated by endogenous reactive oxygen species.

Cytokines and oxidative signalling in skeletal muscle

A growing body of literature indicates that cytokines regulate skeletal muscle function, including gene expression and adaptive responses. Tumour necrosis factor-alpha (TNF-alpha) is the cytokine most prominently linked to muscle pathophysiology and, therefore, has been studied most extensively in muscle-based systems. TNF-alpha is associated with muscle catabolism and loss of muscle function in human diseases that range from cancer to heart failure, from arthritis to AIDS. Recent advances have established that TNF-alpha causes muscle weakness via at least two mechanisms, accelerated protein loss and contractile dysfunction. Protein loss is a chronic response that occurs over days to weeks. Changes in gene expression required for TNF-alpha induced catabolism are regulated by the transcription factor nuclear factor-kappaB which is essential for the net loss of muscle protein caused by chronic TNF-alpha exposure. Contractile dysfunction is an acute response to TNF-alpha stimulation, developing over hours and resulting in decreased force production. Both actions of TNF-alpha involve a rapid rise in endogenous oxidants as an essential step in post-receptor signal transduction. These oxidants appear to include reactive oxygen species derived from mitochondrial electron transport. Such information provides insight into the cellular and molecular mechanisms of TNF-alpha action in skeletal muscle and establishes a scientific basis for continued research into cytokine signalling.

C23 interacts with B23, a putative nucleolar-localization-signal-binding protein

The human protein C23 (nucleolin) is a major nucleolar protein. Its interactions with other proteins were studied with the two-hybrid system which identified nucleolar protein B23 (nucleophosmin) as being associated with C23. Both proteins were co-immunoprecipitated from HeLa cell nuclear extract by either monoclonal anti-C23 or monoclonal anti-B23. Binding studies utilizing deletion mutants indicated that the binding of C23 and B23 involves specific motifs. In addition to an approximately 46-amino-acid-binding domain in B23 (amino acids 194-239), amino acids 540-628 of C23 were required for binding; this region of C23 is required for the nucleolar localization. In addition, nucleolar protein p120 was also found to be co-immunoprecipitated with B23. A fragment of p120 containing a functional nucleolar localization signal bound to the truncated binding domain of B23, as did C23. These results suggest that the interaction of C23 and B23 may represent a nucleolar-targeting mechanism in which B23 acts as a nucleolar-localization signal-binding protein.

Beta-amyloid induces apoptosis in human-derived neurotypic SH-SY5Y cells

Alzheimer's disease is primarily characterized by neurofibrillary tangles, senile plaques, and neurodegeneration. The major component of senile plaques is the beta-amyloid peptide (beta A4), which has been shown to be toxic to neurons in vitro. To date, the mechanism of beta A4-induced neurotoxicity has not been determined in human-derived neurons. In this report, we present evidence that programmed cell death, or apoptosis, is involved in the neurotoxic activity of beta A41-40 and beta A425-35 in the human-derived neurotypic cell line SH-SY5Y cells. The evidence for beta A4-induced apoptosis includes: (1) labeling of cell nuclei for DNA nicked ends; (2) morphological changes in ultrastructure that are consistent with apoptosis (shrunken cells with pyknotic nuclei); (3) DNA laddering which can be blocked by aurintricarboxylic acid (ATA), an inhibitor of apoptosis; and (4) marginal release of intracellular lactate dehydrogenase (LDH), an indicator of necrosis. These results suggest that apoptosis is the major event involved in beta A4-induced cytotoxicity in SH-SY5Y cells. A variety of reagents were tested to determine their activities against beta A4-induced DNA laddering. Nerve growth factor and free radical scavengers were inactive in this system. While ATA blocked DNA laddering resulting from either beta A4 or okadaic acid treatment, Congo red specifically attenuated only beta A4-induced DNA fragmentation. These results suggest that compounds which bind fibrillar beta-peptides can protect this human neurotypic cell line against apoptosis induced by beta A4.

Anticancer activity evaluation of the solanum glycoalkaloid solamargine. Triggering apoptosis in human hepatoma cells

Solamargine, an herbal and molluscicidal medicine derived from Solanum incanum, is a steroidal alkaloid glycoside. To characterize the anticancer mechanism of solamargine on human hepatoma cells (Hep3B), changes of cell morphology, DNA content, and gene expression of cells after solamargine treatment were studied. The appearance in solamargine-treated cells of chromatin condensation, DNA fragmentation, and a sub-G(1) peak in a DNA histogram suggests that solamargine induces cell death by apoptosis. The maximum number of dead Hep3B cells was detected within 2 hr of incubation with constant concentrations of solamargine, and no further cell death was observed after an extended incubation with solamargine, indicating that the action of solamargine was irreversible. To determine the susceptibility of cell phases to solamargine-mediated apoptosis, Hep3B cells were synchronized at defined cell cycles by cyclosporin A, colchicine, and genistein, followed by solamargine treatment. The IC(50) values of solamargine for control, G(0)/G(1)-, M-, and G(2)/M-synchronized Hep3B cells were 5.0, > 10, 3.7, and 3.1 microg/mL, implying that cells in the G(2)/M phases are relatively susceptible to solamargine-mediated apoptosis. In addition, a parallel up-regulation of tumor necrosis factor receptor (TNFR)-I and -II on Hep3B cells was detected after solamargine treatment, and the solamargine-mediated cytotoxicity could be neutralized with either TNFR-I or -II specific antibody. Therefore, these results reveal that the actions of TNFR-I and -II on Hep3B cells may be independent, and both are involved in the mechanism of solamargine-mediated apoptosis.

Long-term efficacy of plasma-derived hepatitis B vaccine: a 15-year follow-up study among Chinese children

To determine necessity and timing of booster of hepatitis B vaccine, we need to observe the duration of its protection. We report the results of a 15-year follow-up of a cohort of 649 children who participated a randomized, double blind, placebo-controlled trial on a plasma-derived hepatitis B vaccine in 1982. During the 15 years after vaccination, more vaccinated children had anti-HBs of 10 S/N ratios or over, compared with the controls, at all nine observations. At 15 years 50.0% (26/52) of the participants studied in the vaccinated group and 33.3% of the tested controls (18/54) retained anti-HBs levels of S/N ratios> or =10 (P < 0.09). However, since 5 years after vaccination, median S/N ratios of anti-HBs among the vaccinated children with detectable anti-HBs were lower than those of the controls except that detected at 15 years. 16.7% (9/54) of the tested children in the control group were HBsAg positive at 15 years after vaccination, in comparison with 1.9% (1/52) of the tested children in the vaccinated (P < 0.02). 28 chronic HBsAg carriers were identified in the control cohort over the 15 years, whereas only 1 case was noted in the vaccinated group (8.2% vs. 0.3%, P < 0.00001), corresponding to an efficacy of 96%.

Expression of 92 kD type IV collagenase/gelatinase B in human osteoclasts

The digestion of type I collagen is an essential step in bone resorption. It is well established that osteoclasts solubilize the mineral phase of bone during the resorptive process, but the mechanism by which they degrade type I collagen, the major proteinaceous component of bone, is controversial. Differential screening of a human osteoclastoma cDNA library was performed to characterize genes specifically expressed in osteoclasts. A large number of cDNA clones obtained by this procedure were found to represent 92 kD type IV collagenase (gelatinase B; MMP-9, EC 3.4.24.35), as well as tartrate-resistant acid phosphatase. In situ hybridization localized mRNA for gelatinase B to multinucleated giant cells in human osteoclastomas. Gelatinase B immunoreactivity was demonstrated in giant cells from eight of eight osteoclastomas, osteoclasts in normal bone, and osteoclasts of Paget's disease by use of a polyclonal antiserum raised against a synthetic gelatinase B peptide. In contrast, no immunoreactivity for 72 kD type IV collagenase (gelatinase A; MMP-2, EC 3.4.24.24), which is the product of a separate gene, was detected in osteoclastomas or normal osteoclasts. We propose that the 92 kD type IV collagenase/gelatinase B plays an important role in the resorption of collagen during bone remodeling.

Cloning and complete coding sequence of a novel human cathepsin expressed in giant cells of osteoclastomas

A gene encoding a possible novel human cathepsin, a cysteine proteinase that is distinct from previously characterized enzymes, has been identified by differential screening of a human osteoclastoma cDNA library. This molecule, termed cathepsin X, appears to represent the human homolog of the osteoclast-expressed rabbit cathepsin OC-2. Cathepsin X (GenBank accession number U20280) is 93.9% identical to OC-2 at the amino acid level, and is 92% identical at the nucleotide level within the coding region. Cathepsin X is 52.2 and 46.9% identical to cathepsins S and L, respectively, and is therefore clearly distinct from these enzymes. Cathepsin X mRNA was localized to multinucleated giant cells within the osteoclastoma tumor by in situ hybridization. These data strongly support the hypothesis that cathepsin X represents a novel cysteine proteinase which is expressed at high levels in osteoclasts.

Effect of tumor necrosis factor-alpha on skeletal muscle metabolism

Over the past year, considerable progress has been made in our understanding of biologic actions by which tumor necrosis factor-alpha (TNF-alpha) may influence skeletal muscle metabolism. Reports published during this period highlighted three general actions with metabolic consequences: accelerated catabolism (protein loss, insulin resistance), contractile dysfunction, and disruption of myogenesis. Recent research also indicates that skeletal muscle myocytes synthesize TNF-alpha and that the cytokine functions as an endogenous mediator of muscle adaptation via autocrine/paracrine effects. These advances demonstrate the fundamental importance of TNF-alpha effects on skeletal muscle myocytes and provide a focus for future studies of intracellular mechanism.

Protein B23 is an important human factor for the nucleolar localization of the human immunodeficiency virus protein Tat

Nucleolar shuttle protein B23 was found to bind to human immunodeficiency virus protein Tat, and this binding required the nucleolar localization motif of Tat. A fusion protein containing the B23 binding domain and beta-galactosidase caused mislocalization of Tat to the cytoplasm and inhibited the transactivation activity of Tat. These data suggest that B23 is a human factor necessary for the nucleolar localization of Tat.

Molecular cloning and characterization of a putative novel human osteoclast-specific 116-kDa vacuolar proton pump subunit

A cDNA encoding a possible novel human 116-kDa polypeptide subunit of the osteoclastic proton pump (OC-116KDa) has been identified by differential screening of a human osteoclastoma cDNA library. The predicted sequence of OC-116kDa consists of 822 amino acids and is 46.9% and 47.2% identical at the amino acid level to the 116-KDa polypeptide of the vacuolar proton pump of rat and bovine brain respectively. OC-116KDa mRNA was found at high levels in osteoclastomas by Northern analysis but was not detected in tumor stromal cells or in other tissues including kidney, liver, skeletal muscle and brain. OC-116KDa mRNA was localized to multinucleated giant cells within the osteoclastoma tumor by in situ hybridization.

Establishment and characterization of two epithelial tumor cell lines (HNE-1 and HONE-1) latently infected with Epstein-Barr virus and derived from nasopharyngeal carcinomas

Two epithelial tumor cell lines were established from biopsy specimens of 2 nasopharyngeal carcinomas (NPC) and designated HNE-1 and HONE-1. Uncloned HNE-1 cells were found to be Epstein-Barr virus (EBV) DNA-positive when examined by Southern blot analysis up to passage 35, after which the EBV genome could no longer be detected. A similar loss of EBV DNA took place in uncloned HONE-1 cells. However, HONE-1 clone 40 cells are still EBV DNA-positive up to passage 42 thus far and cell cultures contain 85-90% EBV nuclear antigen (EBNA)-positive cells. The HNE-1 cell line has been passaged more than 100 times and the uncloned HONE-1 cells more than 90 times. The tumorigenicity of the HNE-1 and HONE-1 cells was demonstrated by tumor induction in nude mice. Karyotypic analysis of the HNE-1 cells demonstrated an aneuploidy with a modal chromosomal number of 74 at passages 5 and 101 at passage 20; 18 marker chromosomes were identified. We have continued to map the EBV genome latently associated with the HNE-1 and HONE-1 cells using the Bam HI, EcoRI or Hind III restriction enzymes. Using EcoRI fragments A-K as probes, we found that HNE-1 EBV DNA is different from B95-8 and HR-1 EBV DNA in the EcoRI-C region. The Bam HI map for HONE-1 EBV DNA is very similar to the B95-8 map; it contains the Bam HI-Y fragment but without Bam HI B' and WI'. Differences were observed between HONE-1 EBV DNA and B95-8 DNA using the Hind III restriction enzyme. There was no evidence of spontaneous expression of the latent EBV genome in HNE-1 cells, and attempts to induce replication of the latent EBV genome and rescue infectious virus have failed, suggesting a tightly restricted virus genome.

Mitochondria mediate tumor necrosis factor-alpha/NF-kappaB signaling in skeletal muscle myotubes

Tumor necrosis factor-alpha (TNF-alpha) is implicated in muscle atrophy and weakness associated with a variety of chronic diseases. Recently, we reported that TNF-alpha directly induces muscle protein degradation in differentiated skeletal muscle myotubes, where it rapidly activates nuclear factor kappaB (NF-kappaB). We also have found that protein loss induced by TNF-alpha is NF-kappaB dependent. In the present study, we analyzed the signaling pathway by which TNF-alpha activates NF-kappaB in myotubes differentiated from C2C12 and rat primary myoblasts. We found that activation of NF-kappaB by TNF-alpha was blocked by rotenone or amytal, inhibitors of complex I of the mitochondrial respiratory chain. On the other hand, antimycin A, an inhibitor of complex III, enhanced TNF-alpha activation of NK-kappaB. These results suggest a key role of mitochondria-derived reactive oxygen species (ROS) in mediating NF-kappaB activation in muscle. In addition, we found that TNF-alpha stimulated protein kinase C (PKC) activity. However, other signal transduction mediators including ceramide, Ca2+, phospholipase A2 (PLA2), and nitric oxide (NO) do not appear to be involved in the activation of NF-kappaB.

DNA hypermethylation of the forkhead box protein 3 (FOXP3) promoter in CD4+ T cells of patients with systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) is a complex autoimmune disease that involves dysregulation of immune homeostasis. The failure of impaired regulatory T cells (Tregs) to maintain immune homeostasis plays a major role in the development of SSc. Transcriptional silencing of the forkhead box protein 3 gene (FOXP3) via hypermethylation of regulatory regions has been identified as a hallmark of committed Tregs and several autoimmune disorders.

OBJECTIVES

To investigate whether aberrant expression and methylation of FOXP3 occurs in CD4+ T cells of patients with SSc and their roles in the pathogenesis of SSc.

METHODS

FOXP3 expression in CD4+ T cells was measured by real-time quantitative reverse-itranscriptase polymerase chain reaction and western blot. Bisulfite sequencing was performed to determine the methylation status of the FOXP3 proximal promoter sequence. The percentage of Treg cells was estimated by flow cytometry.

RESULTS

Decreased FOXP3 expression was observed in CD4+ T cells from patients with SSc. The methylation levels of the FOXP3 regulatory sequences were elevated and inversely correlated with FOXP3 mRNA expression in patients with SSc. The number of Tregs was significantly reduced in patients with SSc. Treatment of SSc CD4+ T cells with a DNA methylation inhibitor, 5-azacytidine, reduced the mean methylation levels, and enhanced FOXP3 expression and Treg generation. The promoter methylation status and expression level of FOXP3 are significantly associated with disease activity.

CONCLUSIONS

The contribution of the hypermethylation of the FOXP3 promoter to decreased FOXP3 expression and the subsequent quantitative defects of Tregs may mediate the immune dysfunction in SSc.

Characterization of mouse cathepsin K gene, the gene promoter, and the gene expression

Cathepsin K, a lysosomal cysteine protease, is abundantly and selectively expressed in osteoclasts and has a specialized role in osteoclast-mediated bone resorption. In contrast to function studies, transcription regulation of cathepsin K remains largely unknown. In this study, the gene encoding mouse cathepsin K and the promoter have been isolated and completely sequenced. In addition, the temporal and spatial expressions of cathepsin K have been characterized. Intrachromosomal mapping studies revealed that the gene contains eight exons and seven introns spanning approximately 10.6 kb of genomic DNA, a genomic organization that was highly conserved with respect to its human homology. Analysis of the 9 kb 5' flanking region indicates that this gene lacks canonical TATA and CAAT boxes and contains multiple putative transcription regulatory elements which are also present in the comparable position of 5' flanking region of human cathepsin K gene. Mouse cathepsin K was found to be a single-copy gene. Northern blot analysis of RNAs from a number of mouse tissues revealed that cathepsin K mRNA is selectively expressed in osteoclast. The selective expression of cathepsin K was confirmed by anticathepsin K immunohistochemical staining. The sequence of cathepsin K expression was linked to osteoclast differentiation in vivo and in vitro by a tartrate-resistant acid phosphatase-anticathepsin K dual immunostaining technique. Cathepsin K is initially expressed at the preosteoclast stage and throughout the mature osteoclast stage. The primer extension assay indicated a major transcription start site 58 bp upstream of the initiator Met codon. The characterization of the cathepsin K gene, its promoter, and the temporal and spatial expression may provide valuable insights into its osteoclast-specific expression and the molecular mechanisms responsible for osteoclast activation.

Acupuncture for stroke rehabilitation

BACKGROUND

Stroke is the third leading cause of death in Western society; in China it is the second most common cause of death in cities and the third in rural areas. It is also a main cause of adult disability and dependency. Acupuncture for stroke has been used in China for hundreds of years and is increasingly practiced in some Western countries.

OBJECTIVES

To assess the efficacy and safety of acupuncture for patients with stroke in the subacute or chronic stage.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (November 2005), the Cochrane Complementary Medicine Field Trials Register (November 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2005), MEDLINE (1966 to November 2005), EMBASE (1980 to November 2005), CINAHL (1982 to November 2005), AMED (1985 to November 2005), the Chinese Stroke Trials Register (November 2005), the Chinese Acupuncture Trials Register (November 2005), the Chinese Biological Medicine Database (1977 to November 2005), the National Center for Complementary and Alternative Medicine Register (November 2005), and the National Institute of Health Clinical Trials Database (November 2005). We handsearched four Chinese journals and checked reference lists of all papers identified for further trials.

SELECTION CRITERIA

Truly randomised unconfounded clinical trials among patients with ischemic or hemorrhagic stroke, in the subacute or chronic stage, which compared acupuncture involving needling with either placebo acupuncture, sham acupuncture or no acupuncture.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed quality, extracted and cross-checked the data.

MAIN RESULTS

Five trials (368 patients) met the inclusion criteria. Methodological quality was considered inadequate in all trials. Although the overall estimate from four trials suggested the odds of improvement in global neurological deficit was higher in the acupuncture group compared with the control group (odds ratio (OR) 6.55, 95% confidence interval (CI) 1.89 to 22.76), this estimate may not be reliable since there was substantial heterogeneity (I(2 )= 68%). One trial showed no significant improvement of motor function between the real acupuncture group and the sham acupuncture group (OR 9.00, 95% CI 0.40 to 203.30), but the confidence interval was wide and included clinically significant effects in both directions. No data on death, dependency, institutional care, change of neurological deficit score, quality of life or adverse events were available.

AUTHORS' CONCLUSIONS

Currently there is no clear evidence on the effects of acupuncture on subacute or chronic stroke. Large, methodologically-sound trials are required.

Survival of the Q fever agent Coxiella burnetii in the phagolysosome

The Q fever agent, Coxiella burnetii, thrives in the acidic environment of the phagolysosome of the host cell. How this obligate intracellular agent manages to survive within this hostile milieu is unknown; however, several of its enzymes may eliminate or prevent the formation of toxic oxygen metabolites by the host cell. Also implicated as virulence factors are its surface lipopolysaccharide and plasmids.