Possible role of Mycoplasma fermentans in pathogenesis of rheumatoid arthritis

The Relationship between Mycoplasmas and Cancer: Is It Fact or Fiction ? Narrative Review and Update on the Situation

More than one million new cancer cases occur worldwide every year. Although many clinical trials are applied and recent diagnostic tools are employed, curing cancer disease is still a great challenge for mankind. Heredity and epigenetics are the main risk factors often related to cancer. Although, the infectious etiological role in carcinogenesis was also theorized. By establishing chronic infection and inflammation in their hosts, several microorganisms were suggested to cause cell transformation. Of these suspicious microorganisms, mycoplasmas were well regarded because of their intimate parasitism with host cells, as well as their silent and insidious role during infections. This assumption has opened many questions about the real role played by mycoplasmas in oncogenesis. Herein, we presented a sum up of many studies among the hundreds which had addressed the Mycoplasma-cancer topic over the past 50 years. Research studies in this field have first started by approving the mycoplasmas malignancy potential. Indeed, using animal models and in vitro experiments in various cell lines from human and other mammalians, many mycoplasmas were proven to cause varied modifications leading to cell transformation. Moreover, many studies have looked upon the Mycoplasma-cancer subject from an epidemiological point of view. Diverse techniques were used to assess the mycoplasmas prevalence in patients with cancer from different countries. Not less than 10 Mycoplasma species were detected in the context of at least 15 cancer types affecting the brain, the breast, the lymphatic system, and different organs in the genitourinary, respiratory, gastrointestinal, and urinary tracts. Based on these revelations, one should concede that detection of mycoplasmas often linked to ‘‘wolf in sheep's clothing” is not a coincidence and might have a role in cancer. Thorough investigations are needed to better elucidate this role. This would have a substantial impact on the improvement of cancer diagnosis and its prevention.

[Clinical implications of the genus Mycoplasma]

Dentro del género Mycoplasma, las especies que tradicionalmente se han relacionado con cuadros infecciosos han sido principalmente M. pneumoniae, M. genitalium, M. hominis o U. urealyticum. Sin embargo, existen otras muchas que están implicadas y, que muchas veces, son desconocidas para los profesionales sanitarios. El objetivo de esta revisión es identificar todas las especies del género Mycoplasma que se han aislado en el hombre y determinar su participación en la patología infecciosa humana.

Effects of Ureaplasma urealyticum lipid-associated membrane proteins on rheumatoid arthritis synovial fibroblasts

Objectives

As an infectious agent might play a role in rheumatoid arthritis (RA) development, this study investigated effects of Ureaplasma urealyticum lipid-associated membrane proteins (UuLAMPs) on RA synovial fibroblast (RASF) proliferation, and tumour necrosis factor (TNF)-α and interleukin (IL)-1β production by THP-1 macrophages. Possible immunogenic proteins in UuLAMPs were identified.

Methods

RASFs were cultured from synovial tissue from donors with RA. Serum samples from donors with/without RA and with/without U. urealyticum infection were used for immunogenicity analyses. THP-1 macrophages served as a model for synovial macrophages. TNF-α and IL-1β mRNA levels were assessed using reverse transcription–polymerase chain reaction; protein levels were estimated using enzyme-linked immunosorbent assay. UuLAMPs underwent separation and Western blot analyses.

Results

UuLAMPs (0.025–0.4 µg/ml) stimulated RASF proliferation in a dose- and time-dependent manner, and increased TNF-α and IL-1β levels in THP-1 macrophages. Several immunogenic UuLAMPs were identified, but antibodies to a 25 kDa protein were only found in RA patients with U. urealyticum infection.

Conclusions

UuLAMPs might induce RASF proliferation and proinflammatory cytokine secretion in synovium from RA patients. A 25 kDa U. urealyticum protein might act as a cross-reactive antigen.

Animal model of Mycoplasma fermentans respiratory infection

Background

Mycoplasma fermentans has been associated with respiratory, genitourinary tract infections and rheumatoid diseases but its role as pathogen is controversial. The purpose of this study was to probe that Mycoplasma fermentans is able to produce respiratory tract infection and migrate to several organs on an experimental infection model in hamsters. One hundred and twenty six hamsters were divided in six groups (A-F) of 21 hamsters each. Animals of groups A, B, C were intratracheally injected with one of the mycoplasma strains: Mycoplasma fermentans P 140 (wild strain), Mycoplasma fermentans PG 18 (type strain) or Mycoplasma pneumoniae Eaton strain. Groups D, E, F were the negative, media, and sham controls. Fragments of trachea, lungs, kidney, heart, brain and spleen were cultured and used for the histopathological study. U frequency test was used to compare recovery of mycoplasmas from organs.

Results

Mycoplasmas were detected by culture and PCR. The three mycoplasma strains induced an interstitial pneumonia; they also migrated to several organs and persisted there for at least 50 days. Mycoplasma fermentans P 140 induced a more severe damage in lungs than Mycoplasma fermentans PG 18. Mycoplasma pneumoniae produced severe damage in lungs and renal damage.

Conclusions

Mycoplasma fermentans induced a respiratory tract infection and persisted in different organs for several weeks in hamsters. This finding may help to explain the ability of Mycoplasma fermentans to induce pneumonia and chronic infectious diseases in humans.

Genomic features and insights into the biology of Mycoplasma fermentans

We present the complete genomic sequence of Mycoplasma fermentans, an organism suggested to be associated with the pathogenesis of rheumatoid arthritis in humans. The genome is composed of 977 524 bp and has a mean G+C content of 26.95 mol%. There are 835 predicted protein-coding sequences and a mean coding density of 87.6 %. Functions have been assigned to 58.8 % of the predicted protein-coding sequences, while 18.4 % of the proteins are conserved hypothetical proteins and 22.8 % are hypothetical proteins. In addition, there are two complete rRNA operons and 36 tRNA coding sequences. The largest gene families are the ABC transporter family (42 members), and the functionally heterogeneous group of lipoproteins (28 members), which encode the characteristic prokaryotic cysteine ‘lipobox’. Protein secretion occurs through a pathway consisting of SecA, SecD, SecE, SecG, SecY and YidC. Some highly conserved eubacterial proteins, such as GroEL and GroES, are notably absent. The genes encoding DnaK-DnaJ-GrpE and Tig, forming the putative complex of chaperones, are intact, providing the only known control over protein folding. Eighteen nucleases and 17 proteases and peptidases were detected as well as three genes for the thioredoxin-thioreductase system. Overall, this study presents insights into the physiology of M. fermentans, and provides several examples of the genetic basis of systems that might function as virulence factors in this organism.

Enzymatic synthesis of Mycoplasma fermentans specific glycoglycerophospholipid from 1,2-dipalmitoylglycerol

A gene, mf3, encoding glycosyltransferase in glycoglycerophospholipid (GGPL; GGPL-I and GGPL-III) biosynthesis in Mycoplasma fermentans PG18 was identified by genomic analysis, cloned, modified codon usage, and expressed in Escherichia coli. The mf3 gene consists of an open reading frame of 1221 bp encoding 406 amino acids. The mf3 gene product, Mf3, has 27% amino acid homology with glycosyltransferase of Borrelia burgdorferi but no homology to genes of other Mycoplasma species in the GenBank database. The reaction product of Mf3 using 1,2-dipalmitoilglycerol and UDP-glucose as substrates showed a specific sodium adducted ion at m/z 753, which corresponded to glucopyranosyl dipalmitoilglycerol as determined by MALDI-TOF mass spectrometry. Furthermore, in the reaction product by Mf3 and Mf1 which was a cholinephosphotransferase and previously cloned from M. fermentans PG18, an ion at m/z 896 corresponding to GGPL-I was detected by mass spectrometry. The product ions of choline, phosphocholine, and hexose-bound phosphocholine were detected by tandem MS analysis of protonated molecules at m/z 896. From these results, mf3 was identified as a glycosyltransferase. It was suggested that glucose transfer and phosphocholine transfer to 1,2-dipalmitoylglycerol are involved in the GGPL biosynthesis pathway of M. fermentans PG18.

The importance of B-cells and ecto-5'nucleotidase in Mycoplasma fermentans infection and the relevance to rheumatoid arthritis

The aim of this work was to discover if Mycoplasma fermentans, which is known to infect B cells, could be the cause of the raised ecto-5'-nucleotidase observed in the synovial fluid of rheumatoid arthritis patients. The ecto-5'-nucleotidase activity in the patients' serum has been shown to correlate with the erythrocyte sedimentation rate and DNA from the mycoplasma has been found in the synovial fluid. B lymphoblastoid cell lines were exposed to 16 strains of Mycoplasma fermentans and their ecto-5'-nucleotidase, CD73, was measured both biochemically and by mouse antibodies to human ecto 5'-nucleotidase using the fluorescence activated cell sorter. The type strain, PG 18, did not grow with the B cells. Some of the mycoplasma strains (9/15) increased the cellular ecto-5'-nucleotidase activity from twice to 17 fold, and usually showed 5'-nucleotidase activity themselves. At least one strain, M106, induced human 5'-nucleotidase on the normally 5'-nucleotidase negative Daudi and Raji Burkitt's lymphoma cell lines, and increased sevenfold the 5'-nucleotidase on the monocyte/macrophage cell line THP-1. Growing the cells in aged medium increased the level of mycoplasma infection. This mycoplasma-induced enzyme showed a conformational change and an increase in activity with a glycosylation change involving mannose groups. The other group of strains, mostly of respiratory or cell culture origin, usually did not have any 5'-nucleotidase of their own and decreased the B-cell enzyme activity by about half. Electron microscopy and flow cytometry showed that the strain M106 was filamentous and could be found inside the B-cells. The 5'-nucleotidase-inducing strains of M. fermentans may be important in the aetiology of rheumatoid arthritis.

A model of the deciliation process caused by Mycoplasma fermentans strain incognitus on respiratory epithelium

The aim of this study was to investigate by light microscopy as well as by scanning and transmission electron microscopy the deciliation process which takes place on the respiratory epithelium of tracheal explants after experimental infection with Mycoplasma fermentans strain incognitus. Time-point photography allowed distinguishing five phases which occurred during the infection on the epithelial cell surface: (1) Attachment of M. fermentans to the cilia causing clumping of the cilia tips; (2) matting of cilia into bundles; (3) formation of abnormally shaped and shorter cilia; (4) collapse of cilia onto the epithelial cell surface; and (5) widespread loss of cilia. Based on the photographic images, a schematic model of the deciliation process was developed. Various potential factors contributing to the cilia destruction are discussed, including the release of mycoplasmal toxins, the physical presence of a high number of M. fermentans cells attached to the cilia, and the depletion of culture medium components by the mycoplasmas. This model of M. fermentans strain incognitus infection of respiratory epithelium is important for understanding mycoplasmal pathogenicity on a comparative level.

The Mycoplasma fermentans prophage φMFV1: genome organization, mobility and variable expression of an encoded surface protein

The approximately 16 kb genome of the Mycoplasma fermentans phiMFV1 prophage is described, and its mobility, replication and effect on the mycoplasma surface phenotype are demonstrated. In various M. fermentans strains, phiMFV1 was either absent or integrated at diverse (and sometimes multiple) chromosomal sites, each marked by a conserved TTTTTA target sequence that is duplicated upon integration. Precise excision, replication of an extrachromosomal form and loss of phiMFV1 from the mycoplasmal genome were documented in a series of clonal derivatives of M. fermentans propagated in culture. Of 18 open reading frames (ORFs) encoded by phiMFV1, most can be ascribed functions related to phage biology, whereas one encodes a unique coiled-coil membrane surface protein, Mem, that was confirmed to be expressed in propagating populations of M. fermentans. With the exception of Mem and other minor ORFs, the striking similarity between the deduced proteomes of phiMFV1 and the recently described phiMAV1 of arthritogenic strains of Mycoplasma arthritidis, along with the prominent gene synteny between these elements, provides the taxonomic basis for a new family of prophage. Their coding features are consistent with long-term residence in mycoplasma genomes and the divergence of species within a phylogenetic clade of mycoplasmas. The unique Mem protein expressed from phiMFV1 and the unique hypothetical surface lipoproteins encoded by phiMAV1 and phiMFV1 also suggest that prophage-associated genes may provide specific, selectable phenotypic traits during co-evolution of mycoplasma species with their respective mammalian hosts. Retention of these labile prophage elements in organisms with such drastically reduced genome sizes implies a significant role in adaptation and survival.

PCR methods in clinical investigations of human ureaplasmas: a minireview

Human ureaplasmas are small, cell-wall-deficient organisms that are implicated in many human infections. Due to their small size and fastidious growth requirements, ureaplasmal infections are hard to diagnose clinically, and ureaplasmal disease is difficult to study in clinical samples. Standard culture methods for ureaplasmas are technically challenging, and 3 to 5 days are required to identify this pathogen. PCR methods have been increasingly used in the diagnosis of these infections and in the study of this pathogen in human specimens from multiple sites. These methods have theoretical advantages over traditional culture methods. Organism identification can occur in the presence of low numbers of bacteria, and viability is not necessary. Rapid identification of organisms within 24 h is also possible. In addition, subtyping of isolates can be performed faster with PCR methods than with culture methods. The use of PCR methods in translational research in multiple human ureaplasmal diseases will be reviewed in this paper, and their usefulness will be compared to culture methods.

Mycoplasmal lipoproteins induce toll-like receptor 2- and caspases-mediated cell death in lymphocytes and monocytes

Lipoproteins of Mycoplasma salivarium and Mycoplasma fermentans preferentially induced necrotic cell death in lymphocytic cell lines, MOLT-4 and Raji, and in one monocytic cell line, THP-1, whereas they preferentially induced apoptotic cell death in another monocytic cell line, HL-60. These findings were also supported by ultrastructural observations by the use of scanning and transmission electron microscopes and by agarose gel electrophoresis of the genomic DNA. The lipoproteins activated caspase-3 in both MOLT-4 and HL-60 cells, which was assessed by the cleavage of the synthetic substrate DEVD-pNA and the endogenous substrate poly(ADP-ribose) polymerase. The cytotoxicity to MOLT-4 and HL-60 cells was inhibited by various caspase inhibitors, Ac-DMQD-CHO, Ac-IETD-CHO, and Z-VAD-FMK. The cytotoxicity was also partially suppressed by the monoclonal antibody to Toll-like receptor 2. Thus this study demonstrated that mycoplasmal lipoproteins induce caspases-dependent necrotic and apoptotic cell death in lymphocytes and monocytes/macrophages, which is partially induced by TLR2-mediated signaling.

Signaling pathways induced by lipoproteins derived from Mycoplasma salivarium and a synthetic lipopeptide (FSL-1) in normal human gingival fibroblasts

Lipoproteins derived from Mycoplasma salivarium and a synthetic lipopeptide (FSL-1) activate human gingival fibroblasts to induce IL-6 production and ICAM-1 expression. Human gingival fibroblasts were treated with lipoproteins or FSL-1 and then examined for the activation of mitogen-activated protein kinases (MAPKs), ERK1/2, p38, and SAPK/JNK, and transcription factors, AP-1 and NF-kappaB. Western blotting indicated that p38 and SAPK/JNK were activated in response to the stimulators, but the activation of ERK1/2 could not be discriminated because ERK1/2 was activated in the absence of stimulators. The p38 inhibitor SB 203580 also suppressed their IL-6 production-inducing activities, whereas the ERK1/2-activating MAPK kinase (MEK1) inhibitor PD 98059 did not suppress their activities. Moreover, they were capable of inducing the activation of AP-1 and NF-KB. NF-kappaB activation was also confirmed by the phosphorylation of IkappaB-alpha. On the basis of these results, it was concluded that lipoproteins of M. salivarium and FSL-1 are capable of activating the MAPKs p38 and SAPK/JNK and the transcriptional factors AP-1 and NF-kappaB in human gingival fibroblasts.

Choline-containing lipids in mycoplasmas

Choline-containing lipids were identified and characterized in the cell membrane of Mycoplasma fermentans and were shown to participate in the adhesion to the surface of eukaryotic cells, to stimulate mycoplasma fusion with eukaryotic cells, and to induce cytokine secretion by cells of the immune system. These findings suggest that choline-containing lipids are important mediators of tissue pathology in the infectious process caused by M. fermentans.

Experimental arthritis induced by a clinical Mycoplasma fermentans isolate

BACKGROUND

Mycoplasma fermentans has been associated with rheumatoid arthritis. Recently, it was detected in the joints and blood of patients with rheumatoid arthritis, but it is not clear yet how the bacteria enter the body and reach the joints. The purpose of this study was to determine the ability of M. fermentans to induce experimental arthritis in rabbits following inoculation of the bacteria in the trachea and knee joints.

METHODS

P-140 and PG-18 strains were each injected in the knee joints of 14 rabbits in order to evaluate and compare their arthritogenicity. P-140 was also injected in the trachea of 14 rabbits in order to test the ability of the bacteria to reach the joints and induce arthritis.

RESULTS

M. fermentans produced an acute arthritis in rabbits. Joint swelling appeared first in rabbits injected with P-140, which caused a more severe arthritis than PG-18. Both strains were able to migrate to the uninoculated knee joints and they were detected viable in the joints all along the duration of the experiment. Changes in the synovial tissue were more severe by the end of the experiment and characterized by the infiltration of neutrophils and substitution of adipose tissue by connective tissue. Rabbits intracheally injected with P-140 showed induced arthritis and the bacteria could be isolated from lungs, blood, heart, kidney, spleen, brain and joints.

CONCLUSION

M. fermentans induced arthritis regardless of the inoculation route. These findings may help explain why mycoplasmas are commonly isolated from the joints of rheumatic patients.

A 4.1-kilodalton polypeptide in the cultural supernatant of Mycoplasma fermentans is one of the substances responsible for induction of interleukin-6 production by human gingival fibroblasts

The cultural supernatant of Mycoplasma fermentans induced interleukin-6 production by human gingival fibroblasts. The active entities were divided into hydrophilic and hydrophobic substances. In this study, we purified a 4.1-kilodalton polypeptide from the hydrophilic substances. It reacted with polyclonal antibodies to M. fermentans and activated human macrophages.

The physico-chemical characteristics of the phosphocholine-containing glycoglycerolipid MfGL-II govern the permeability properties of Mycoplasma fermentans

Mycoplasma fermentans seems to be involved in several pathogenic conditions in humans, and is among other things capable of fusing with T-cells and lymphocytes. The choline-containing phosphoglycolipid 6'-O-(3"-phosphocholine-2"-amino-1"-phospho-1",3"-propanediol)-alpha-D-glucopyranosyl-(1'-->3)-1,2-diacylglycerol (MfGL-II) in the membrane of M. fermentans has been suggested to enhance the fusion process, and the characteristics of MfGL-II were therefore investigated. When a cell culture ages the fraction of MfGL-II increases, and the fraction of the other major membrane lipid, phosphatidylglycerol (PtdGro), decreases concomitantly. Swelling experiments showed that the permeability and osmotic fragility are markedly reduced in aged cells. MfGL-II is selectively released into the surrounding medium when aged M. fermentans cells are incubated in buffer containing EDTA. The physico-chemical properties of MfGL-II were studied by NMR spectroscopy and differential scanning calorimetry, and they can explain the biochemical results. The temperature for the transition between gel and lamellar liquid crystalline (Lalpha) phases is 35-45 degrees C higher for MfGL-II than for PtdGro, which most probably gives rise to the reduced permeability in aged cells. At high water contents MfGL-II forms an Lalpha phase and isotropic aggregates which were interpreted to be vesicles with a radius of approximately 450 A. It is proposed that MfGL-II forms vesicles in the surrounding medium when it is released from the cell membrane. Neither EDTA nor Ca2+ ions have a significant influence on the aggregate structures formed by MfGL-II. Our results indicate that MfGL-II has no fusogenic properties. It is more probable that a recently identified lysolipid in the M. fermentans membrane acts as a fusogen.

Monoclonal antibody against Mycoplasma fermentans-specific aminoglycoglycerolipid

Previously, we reported that Mycoplasma fermentans has specific antigens (phosphocholine-containing glycoglycerolipids: GGPL-I and GGPL-III) and discussed the possibility of their pathogenic role. In this paper, we report the characterization of a monoclonal antibody (MF-III-1) specific to GGPL-III (phosphocholine-containing aminoglycoglycerolipid) using methods of electron microscopy, immunofluorescence cell surface staining, laser scanning microscopy, immunoelectron microscopy, and thin-layer chromatography immunostaining. The MF-III-1 antibody specifically recognized M. fermentans attached to the surface of HTLV-I-infected human helper T-cells, and it did not cross-react with other lipids nor with human T-cell antigens. Since MF-III-1 distinguishes GGPL-III from GGPL-I, the binding site may include a serinol (2-amino-1,3-propanediol) residue of GGPL-III. MF-III-1 is useful for the in vitro study of M. fermentans, and may also be useful as a tool for the study of the involvement of M. fermentans in human diseases.

Distribution of ecto 5'-nucleotidase on Mycoplasma species associated with arthritis

The enzyme ecto 5'-nucleotidase (5'N) was found to be active on 8/14 strains of Mycoplasma fermentans, K(m) (+/-S.D.) 3.8+/-2.8 microM 5'-AMP, and on the type strain of Mycoplasma pulmonis, K(m) 0.63 microM 5'-AMP. The six M. fermentans strains lacking 5'N activity were related by restriction fragment length polymorphism typing. At pH 8.5, the type strains of Mycoplasma arthritidis, Mycoplasma buccale and Ureaplasma urealyticum showed a relatively non-specific phosphatase activity against 5'-AMP but no activity was shown by the type strains of Mycoplasma genitalium, Mycoplasma hominis, Mycoplasma orale, Mycoplasma penetrans, Mycoplasma pneumoniae and Mycoplasma salivarium at this pH. M. fermentans has been reported from rheumatoid joints, which show a raised 5'N activity on their synovial cells and in their fluid which may be associated directly or indirectly with the mycoplasma.

Tetracyclines for the treatment of rheumatoid arthritis

In this review the rationale for the possible beneficial effect of tetracycline derivatives for the treatment of rheumatoid arthritis is discussed. Early studies (Sanchez, Skinner et al. and Brown et al. ) and the two open trials of the 1980s are briefly discussed. The three double-blind studies conducted in the 1990s (Kloppenburg et al. , The Netherlands; the MIRA trial, USA and the O'Dell et al., USA) are described in detail. The baseline clinical and demographic data for these patients, as well as the efficacy and toxicity data are described in the text and summarised in tables. The long-term data of the O'Dell et al.'s trial is described. Finally, side effects not observed during the conduct of these trials, but reported to occur in other patients, for example those receiving minocycline for the treatment of acne, are also listed.

Identification of Mycoplasma fermentans in synovial fluid samples from arthritis patients with inflammatory disease

Since 1970 Mycoplasma fermentans has been suspected of being associated with rheumatoid arthritis. However, this association has been difficult to prove, and this has been our goal. The distribution of M. fermentans was studied in the synovial fluid of patients suffering from different arthritides. Samples of synovial fluid were taken from patients with well-defined disease and a clear diagnosis. After removal of the inflammatory cells and hyaluran, they were treated with proteinase K and tested by a single or fully nested PCR with primers directed against part of the two 16S rRNA genes of M. fermentans. The product was sequenced automatically, by using an ALF Express automatic sequencer, to confirm the mycoplasma species and to identify the strain since the two genes were usually found to be polymorphic. This was also true of the type strain, strain PG18. M. fermentans was detected in 23 of 26 (88%) rheumatoid arthritis patients, and four different strains were found. It was also found in 7 of 8 (88%) of the nonrheumatoid inflammatory arthritis patient group, which consisted of one patient with reactive arthritis, one patient with pauciarticular juvenile chronic arthritis, two patients with gout, two patients with ankylosing spondylitis, and two patients with psoriatic arthritis, only one of whom was infected with M. fermentans. It was not detected in any of the 10 osteoarthritis patients. M. fermentans was therefore found to be a variable and very common organism in arthritic patients with inflammatory joint exudates and may well prove to be important in the etiology of the diseases.

Effect of MALP-2, a lipopeptide from Mycoplasma fermentans, on bone resorption in vitro

Mycoplasmas may be associated with rheumatoid arthritis in various animal hosts. In humans, mycoplasma arthritis has been recorded in association with hypogammaglobulinemia. Mycoplasma fermentans is one mycoplasma species considered to be involved in causing arthritis. To clarify which mycoplasmal compounds contribute to the inflammatory, bone-destructive processes in arthritis, we used a well-defined lipopeptide, 2-kDa macrophage-activating lipopeptide (MALP-2) from M. fermentans, as an example of a class of macrophage-activating compounds ubiquitous in mycoplasmas, to study its effects on bone resorption. MALP-2 stimulated osteoclast-mediated bone resorption in murine calvaria cultures, with a maximal effect at around 2 nM. Anti-inflammatory drugs inhibited MALP-2-mediated bone resorption by about 30%. This finding suggests that MALP-2 stimulates bone resorption partially by stimulating the formation of prostaglandins. Since interleukin-6 (IL-6) stimulates bone resorption, we investigated IL-6 production in cultured calvaria. MALP-2 stimulated the liberation of IL-6, while no tumor necrosis factor was detectable. Additionally, MALP-2 stimulated low levels of NO in calvaria cultures, an effect which was strongly increased in the presence of gamma interferon, causing an inhibition of bone resorption. MALP-2 stimulated the bone-resorbing activity of osteoclasts isolated from long bones of newborn rats and cultured on dentine slices without affecting their number. In bone marrow cultures, MALP-2 inhibited the formation of osteoclasts. It appears that MALP-2 has two opposing effects: it increases the bone resorption in bone tissue by stimulation of mature osteoclasts but inhibits the formation of new ones.

Detection of Mycoplasma fermentans in saliva sampled from infants, preschool and school children, adolescents and adults by a polymerase chain reaction-based assay

Attempts were made to detect Mycoplasma fermentans in saliva sampled from 201 subjects (108 males and 93 females) aged from 4 months to 59 years by a polymerase chain reaction-based assay. M. fermentans was detected in saliva from 110 (54.7%) of 201 subjects, and 10 (28.6%) of 35 subjects aged from 4 months to 3 years. Of ten positive subjects, three were aged from 16 to 23 months and five were from 26 to 31 months. The incidence tended to increase with age up to the teens. The incidence was significantly greater in teenagers than in subjects aged from 7 to 12 years, but there was no significant difference in the incidence between the group of teenagers and each of the groups of subjects older than the teenagers. Thus, it was suggested that M. fermentans colonized the mouth at the age of about 16 months up to the age of 19 years.

Transcriptional activation of mRNA of intercellular adhesion molecule 1 and induction of its cell surface expression in normal human gingival fibroblasts by Mycoplasma salivarium and Mycoplasma fermentans

Lipoproteins in the cell membranes of both Mycoplasma salivarium and Mycoplasma fermentans were demonstrated to trigger the transcription of intercellular adhesion molecule-1 mRNA in normal fibroblasts isolated from human gingival tissue and to induce its cell surface expression by a mechanism distinct from that of Escherichia coli lipopolysaccharide. The lipid moiety of the lipoproteins was suggested to play a key role in the expression of the activity.

The role of brain cytokines in mediating the behavioral and neuroendocrine effects of intracerebral mycoplasma fermentans

Intracerebral administration of Mycoplasma fermentans (MF), a small microorganism that has been found in the brain of some AIDS patients, induces behavioral and neuroendocrine alterations in rats. To examine the role of tumor necrosis factor-alpha (TNFalpha) and interleukin-1 (IL-1) in mediating these effects we measured MF-induced expression of TNFalpha and IL-1beta mRNA in various brain regions, and the effects of TNFalpha synthesis blockers and IL-1 receptor antagonist (IL-1ra) on MF-induced sickness behavior and adrenocortical activation. Intracerebroventricular (i.c.v.) administration of heat-inactivated MF induced the expression of both TNFalpha and IL-1beta mRNA in the cortex, dorsal hippocampus, amygdala, and hypothalamus. Pre-treatment of rats with either TNFalpha synthesis blockers, pentoxifylline or rolipram, or with IL-1ra did not attenuate MF-induced anorexia, body weight loss, and suppression of social behavior. However, simultaneous administration of both pentoxifylline and IL-1ra markedly attenuated MF-induced anorexia and body weight loss, but had no effect on the suppression of social behavior. Pre-treatment with pentoxifylline, but not with IL-1ra, significantly attenuated MF-induced corticosterone (CS) secretion. Together, these findings indicate that both TNFalpha and IL-1 participate, in a complementary manner, in mediating some of the behavioral effects of MF, whereas only TNFalpha, but not IL-1, is involved in mediating MF-induced adrenocortical activation. We suggest that cytokines within the brain are involved in mediating at least some of the neurobehavioral and neuroendocrine abnormalities that may be produced by MF in AIDS patients.

Detection of Mycoplasma salivarium and Mycoplasma fermentans in synovial fluids of temporomandibular joints of patients with disorders in the joints

Thirty-six synovial fluid samples of temporomandibular joints were obtained from 33 patients with pain and anterior disk displacement (closed lock) in the joints. DNAs were prepared from the samples and amplified by a PCR-based assay specific for Mycoplasma salivarium or Mycoplasma fermentans. Of the 36 samples, five (14%), three (8%), and 19 (53%) were positive for M. salivarium, M. fermentans and both, respectively.

Genotypic and phenotypic analysis of Mycoplasma fermentans strains isolated from different host tissues

A correlation was found between the expression of a specific Mycoplasma fermentans surface antigen (Pra, proteinase-resistant antigen) and the site of isolation of the organism from the infected host. Strains which expressed Pra were most frequently associated with cells of bone marrow origin, and strains which lacked expression of Pra were most commonly isolated from the respiratory tract, genital tract, and arthritic joints, i.e., epithelial cell surfaces. Pra was previously shown to be resistant to degradation by proteinases and was hypothesized to play a protective role at the organism surface and perhaps to influence which host tissue site was colonized by the organism. The methods used for this phenotyping scheme required isolation and growth of the mycoplasma in quantities sufficient for immunoblot analysis using monoclonal antibodies. We wanted to determine a more rapid and less cumbersome technique to supplement this method for determining the Pra phenotype directly in clinical specimens. Here we describe PCR studies to investigate the movement of a previously identified M. fermentans insertion sequence (IS)-like element. These data showed a correlation between a specific IS genotype and the Pra+ phenotype. Production of a 160-bp product using a single set of IS-based primers was associated with expression of Pra. The genomic IS location resulting in the 160-bp product was determined by using Southern blot analysis and was found to be a stable insertion site characteristic of genotype I strains. Additional analyses of sequences within and flanking the IS insertion sites revealed another pair of PCR primer sites which resulted in the consistent production of a 450-bp amplicon. The stability of this site was dependent on the absence of the IS-like element between the primer sites. The production of this 450-bp amplicon correlated with the Pra mutant phenotype and was characteristic of genotype II strains. The data showed that the sequence within the IS may be unstable and that reliable genotyping sequences are more easily found in the stable genomic sites which flank the IS element.

Genotypic characterization of seven strains of Mycoplasma fermentans isolated from synovial fluids of patients with arthritis

We performed a genotypic characterization of seven strains of Mycoplasma fermentans which have been isolated from the synovial fluid of patients with rheumatoid arthritis (n = 2), spondyloarthropathy (n = 1), and unclassified arthritis (n = 4). We compared them to three reference strains (strains PG18 and K7 and incognitus strain) and to a clinical isolate from the urethra of a patient with nongonococcal urethritis. The characterization methods included electrophoresis of native DNA, arbitrarily primed PCR, and restriction fragment length polymorphism analysis following conventional and pulsed-field gel electrophoresis. Southern blot analysis with a probe internal to an insertion sequence was performed with the restriction products produced by the last two techniques. No extrachromosomal DNA sequences were detected. The M. fermentans strains identified by these methods did not present a unique profile, but they could be separated into two main categories: four articular isolates were genetically related to PG18 and the three other isolates, the urethral isolate, and the incognitus strain were related to K7. We also looked for the presence of the bacteriophage MAV1 (associated with the arthritogenic property of Mycoplasma arthritidis in rodents) in the M. fermentans strains. MAV1 DNA was not detected in either the clinical isolates or the reference strains of M. fermentans.

Microbiology of acute arthropathies among children in Argentina: Mycoplasma pneumoniae and hominis and Ureaplasma urealyticum

OBJECTIVE

To describe the isolation of mycoplasmas and ureaplasmas from synovial fluid in pediatric patients with joint disorders.

METHODS

During 1 year 45 samples of synovial fluid, blood and urine were collected from 33 hospitalized pediatric patients up to 17 years old who had joint disorders. Mycoplasmas and ureaplasmas were isolated in joint fluid by culture methods.

RESULTS

Of the 33 patients 12 (36%) had joint disorders associated with pathogens (bacteria, Mycoplasma/Ureaplasma, Chlamydia) present at the site of inflammation. Mycoplasma hominis and Ureaplasma urealyticum were isolated from 3 and 1% of joint fluid samples, respectively. M. pneumoniae was isolated from nasopharyngeal secretion in a patient with evidence of a reactive arthritis.

CONCLUSION

Our results raise the question of the possible role of Mycoplasma as a cofactor in the triggering of inflammatory joint disease, as well as the hypothesis that arthropathies may be caused by chronic local infection. These findings may contribute to early diagnosis of the disease and initiation of specific treatment.

Mycoplasma salivarium induces interleukin-6 and interleukin-8 in human gingival fibroblasts

Analysis by an enzyme-linked immunosorbent assay for cytokines indicated that whole cells, intracellular materials and cell membranes of Mycoplasma salivarium induced interleukin-6 and interleukin-8 in a human gingival fibroblast cell line, Gin-1 cells. This was confirmed by reverse transcription-polymerase chain reaction analysis of mRNAs of these cytokines. Studies with inhibitors of second-messenger pathway indicated that a protein kinase C-dependent pathway was involved in the expression of the activity of the cell membranes. In addition, whole cells of other mycoplasmas (M. hominis, M. arthritidis, M. arginini, M. fermentans, M. penetrans, M. pirum and M. pneumoniae) tested for comparative purposes were also shown to possess the activity. Thus, this study demonstrated that mycoplasmas possess the activity to induce interleukin-6 and interleukin-8 in human fibroblasts.

Structure of a novel phosphocholine-containing aminoglycoglycerolipid of Mycoplasma fermentans

Mycoplasma fermentans is thought to be a pathogen of rheumatoid arthritis or a cofactor of AIDS (acquired immunodeficiency syndrome). To elucidate the possible involvement of membrane constituents in the pathogenesis of these diseases, we studied its lipid components. Several alkali labile glycophospholipids were detected and named glycoglycerophospholipids (GGPLs). Previously, we purified and determined the structure of one of them as 6'-O-phosphocholine-alpha-glucopyranosyl-(1'-3)-1,2-diacyl-sn-glycerol (GGPL-I). The present paper describes the purification and structural characterization of GGPL-III, the major GGPL of M. fermentans using 1H-, 13C- and 31P-nuclear magnetic resonance spectroscopy, and mass-spectroscopy as 1"-phosphocholine,2"-amino dihydroxypropane-3"-phospho-6'-alpha-glucopyranosyl-(1'-3)-1,2-dia cyl-glycerol.

Phosphocholine-containing glycoglycerolipids (GGPL-I and GGPL-III) are species-specific major immunodeterminants of Mycoplasma fermentans

Mycoplasma fermentans has unique glycoglycerophospholipids (GGPLs: GGPL-I and GGPL-III). Previously, the structure of these lipids was determined as phosphocholine-6'-alpha-glucopyranosyl-(1'-3)-1, 2-diacyl-glycerol (GGPL-I) and 1"-phosphocholine-2"-aminodihydroxypropane-3"-phospho-6'-alph++ + a- glucopyranosyl-(1'-3)-1, 2-diacyl-glycerol (GGPL-III). Thin-layer chromatography (TLC) immunostaining showed that the GGPLs were main lipid-antigens of the M. fermentans species. Anti-M. fermentans serum stained mainly the GGPLs, but the other anti-mycoplasma sera (anti-M. arginini, anti-M. hyorhinis, anti-M. pneumonia, anti-M. primatum, and anti-Acholeplasma laidlawii, anti-M. hominis, anti-M. orale, and M. salivarium) stained neither GGPL-I nor GGPL-III. The TLC analysis of glycolipids and phospholipids of various human related mycoplasmas showed clearly that GGPLs are specifically expressed in M. fermentans species. GGPL-I and GGPL-III ranged from 1.6 to 28% and from an undetectable level to 35% of total phospholipids, respectively. Although there was heterogeneity among the amounts of GGPL-I or GGPL-III of M. fermentans strains, all of the M. fermentans strains had GGPL-I and/or GGPL-III. These observations showed that GGPL structures are species-specific immunodeterminants of M. fermentans. The fact that the GGPLs are main phospholipid components of the M. fermentans species means the M. fermentans has a unique choline metabolic pathway. This observation may raise phylogenetic interest.

Intracerebral administration of Mycoplasma fermentans produces sickness behavior: role of prostaglandins

Mycoplasmas are small microorganisms, which cause various diseases in animals and in humans, activate the immune system, and induce the release of various cytokines. Some of the effects of mycoplasmas are mediated by the CNS. Moreover, Mycoplasma fermentans (MF) has recently been found in the brain, as well as other tissues of some AIDS patients, who usually display severe neurobehavioral disturbances. The present study was designed to examine the behavioral effects of central administration of MF, and the role of prostaglandins in mediating these effects. In one set of experiments, rats were injected intracerebroventricularly (i.c.v.) with either saline or a dose of MF (5.1-36 microg per rat), and several behavioral parameters were measured. In addition, body temperature and locomotor activity were continuously monitored by a biotelemetric system. MF induced a significant elevation in body temperature and suppression of motor activity levels. MF also significantly reduced the time spent in social exploration, decreased locomotor and exploratory activity in the open field test, suppressed the consumption of food and saccharine solution, and reduced body weight. In a second set of experiments, i.c.v. administration of MF (7.2 microg) was found to produce a significant increase in the production of prostaglandin E2 (PGE2) in hypothalamic, hippocampal, and cortical tissues. This effect was blocked by indomethacin, a prostaglandin synthesis inhibitor. Indomethacin also attenuated the effects of MF on body temperature, motor activity and body weight, suggesting the involvement of prostaglandins in mediating some of the effects of MF. Together, these findings suggest that the presence of MF in the brain may be responsible for some of the neurobehavioral abnormalities in HIV-infected patients.

Mycoplasma fermentans, but not M penetrans, detected by PCR assays in synovium from patients with rheumatoid arthritis and other rheumatic disorders

AIM/BACKGROUND

Mycoplasmas, especially Mycoplasma fermentans, were suggested more than 20 years ago as a possible cause of rheumatoid arthritis but this hypothesis was never substantiated. In view of the superior sensitivity of the polymerase chain reaction (PCR) assay over culture, the aim was to use this method to seek M fermentans and M penetrans in synovial samples from patients with various arthritides.

METHODS

Synovial fluid samples (n = 154) and synovial biopsy specimens (n = 20) from 133 patients with various rheumatic disorders were stored at -80 degrees C for between one and 40 months. Aliquots (500 microliters) of the synovial fluid samples were centrifuged and the deposit, and also the synovial biopsy specimens (approximately 1 g) were placed in lysis buffer with proteinase K for DNA extraction. The DNA was tested by using a semi-nested PCR assay for M fermentans and a single-round PCR for M penetrans.

RESULTS

M fermentans was detected in the joints of eight (21%) of 38 patients with rheumatoid arthritis, two (20%) of 10 patients with spondyloarthropathy with peripheral arthritis, one (20%) of five patients with psoriatic arthritis, and four (13%) of 31 patients with unclassified arthritis. M fermentans was not found in the joints of the seven patients with reactive arthritis, the 29 with osteoarthritis or post-traumatic hydrarthrosis, the nine with gouty arthritis, nor the four with chronic juvenile arthritis. M penetrans was not detected in any sample.

CONCLUSIONS

These findings show that the presence of M fermentans in the joint is associated with inflammatory rheumatic disorders of unknown cause, including rheumatoid arthritis. However, whether this organism triggers or perpetuates disease of behaves as a passenger remains conjectural.

Mycoplasma fermentans-derived lipid inhibits class II major histocompatibility complex expression without mediation by interleukin-6, interleukin-10, tumor necrosis factor, transforming growth factor-beta, type I interferon, prostaglandins or nitric oxide

Mycoplasma cause several diseases in man and animals. Some strains can chronically infect humans, leading to fever or inflammatory syndromes such as arthritis, particularly in immunosuppressed patients. A set of pathogenicity factors shared by many mollicutes may be membrane components that activate macrophages to secrete cytokines and other inflammatory mediators. Mycoplasma-derived high molecular weight material (MDHM) is a macrophage-activating amphiphilic lipid which was purified from Mycoplasma fermentans. We studied the influence of MDHM on the expression of major histocompatibility complex (MHC) class II molecules by mouse resident peritoneal macrophages with an ELISA. Highly purified MDHM at 4 ng/ml and 0.8 microgram/ml crude heat-killed M. fermentans (concentrations chosen to give maximal responses) suppressed interferon (IFN)-gamma-dependent class II MHC induction when added simultaneously with IFN-gamma. MDHM was not toxic and did not result in loss of adherent cells. Kinetic data showed that MDHM first up-regulated, then down-regulated the expression of preformed class II MHC molecules, while expression of Mac-1 and F4/80 antigens remained constant. MDHM-dependent suppression of class II MHC molecule expression resulted in impaired antigen presentation to the helper T cell line D10.G4.1. We further attempted to identify hypothetical products of MDHM-stimulated macrophages as secondary mediators of class II MHC suppression such as were described for lipopolysaccharide (LPS)-stimulated macrophages. Type I IFN, prostaglandins and nitric oxide, all reported to cause down-regulation of class II MHC, could be excluded in this context. Of the cytokines tumor necrosis factor, interleukin (IL)-6, IL-10 and transforming growth factor-beta, only IL-10 inhibited class II MHC expression, although less effectively than MDHM. The involvement of IL-10 was ruled out, as no evidence for its MDHM-dependent formation could be found. Our data suggest that MDHM interferes with class II MHC expression by up-regulating its turnover, and at the same time, inhibits the formation of new class II MHC molecules.

Identification of phosphocholine-containing glycoglycerolipids purified from Mycoplasma fermentans-infected human helper T-cell culture as components of M. fermentans

Previously, we have reported the occurrence of novel phosphocholine-containing glycoglycerolipids (GGPLs: GGPL-I and GGPL-III) in human helper T-cell (MT-4 cell line) (Mustuda et al, Glycoconjugate J. 10:340). However, the GGPLs disappeared from the MT-4 after treatment with an antimycoplasma agent. This disappearance suggested the involvement of microorganisms in the GGPL expression. In this paper, we show that the novel lipids are components of Mycoplasma fermentans itself. The supernatant fluid of the antimycoplasma agent-untreated Mt-4 cell culture produced mycoplasma-like colonies on PPLO agar plates, and PCR and immunological methods revealed the presence of M. fermentans. GGPLs were expressed again in the treated Mt-4 cells after infection with the isolated M. fermentans. The isolated M. fermentans had glycoglycerolipids corresponding to GGPL-I and GGPL-III. Thin-layer chromatography-mass spectrometry and immunological analyses showed that these glycoglycerolipid which were derived from the isolated M. fermentans were identical with GGPL-I and GGPL-III previously obtained. This is the first report that shows mycoplasma has phosphocholine-containing glycoglycerolipids.

Induction of proto-oncogene and cytokine expression in human peripheral blood monocytes and the monocytic cell line THP-1 after stimulation with mycoplasma-derived material MDHM

Mycoplasma fermentans-derived high-molecular-weight material (MDHM) was originally described to induce differentiation of murine thymocytes to cytolytic effector T-cells by stimulating IL-6 release from adherent cells. This study shows that human peripheral blood monocytes (PBMo) also respond to MDHM with increases in IL-1 beta, IL-6 and TNF alpha expression, both at the mRNA and protein level. The induced expression of IL-1 beta and TNF alpha mRNA in the monocytic THP-1 cell line increased as quickly as in primary cells. In contrast to PBMo, THP-1 and 14 other monocytic/myeloid leukemia-derived cell lines did not secrete measurable amounts of the cytokines upon treatment with MDHM. IL-1 beta and IL-6 genes contain AP-1 binding sites as regulatory elements, the AP-1 protein being composed of c-jun and c-fos gene products. In THP-1 cells c-jun mRNA expression increased after incubation with MDHM while positive c-fos expression remained unaffected. Although these data suggest AP-1 regulated cytokine mRNA expression, results from PBMo are not in accordance with this notion. In the primary cells MDHM-induced elevation of cytokine mRNA levels was preceded by a downregulation of c-fos expression while positive c-jun expression was not modulated. c-myc mRNA expression, constitutively high in THP-1 cells, was induced in MDHM-stimulated PBMo. In conclusion, MDHM-stimulated induction of cytokine mRNA expression was accompanied by different proto-oncogene responses in PBMo and THP-1 cells. These differences may represent different regulatory pathways of the two cell systems. Alternatively, these data support the notion that neither AP-1 nor the c-myc protein are involved in the MDHM-induced increase in IL-1 beta, IL-6 or TNF alpha mRNA levels. Furthermore, the present results demonstrate clearly that mycoplasma products can have a profound impact on the activation status of eukaryotic cells.