Mycoplasma penetrans infections and seroconversion in patients with AIDS: identification of major mycoplasmal antigens targeted by host antibody response

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.

High expression of miR-222-3p in children with Mycoplasma pneumoniae pneumonia

Objectives

Mycoplasma pneumoniae is a leading cause of community-acquired pneumonia in children. However, its mechanism of pathogenesis is not fully understood, and microRNAs might play a role. This study aimed to explore the microRNA-222-3p (miR-222-3p) expression and its possible role in children with M.pneumoniae pneumonia (MPP).

Methods

Thirty-six children with MPP and twenty-seven age-matched controls from Children’s Hospital of Soochow University were enrolled in this study. MiR-222-3p and cluster of differentiation 4 (CD4) mRNA were detected using real-time PCR in children’s peripheral blood plasma samples. THP-1 cells and mice were stimulated with M.pneumoniae lipid-associated membrane proteins(LAMPs).

Results

Children with MPP had significantly higher levels of miR-222-3p and lower levels of CD4 in peripheral blood plasma (P <  0.05). Additionally, Sixteen children with MPP complicated with pleural effusion had higher miR-222-3p levels than those without pleural effusion. MiR-222-3p or CD4 in THP-1 cells increased or decreased, respectively, in a dose dependent manner after LAMP stimulation. In LAMP-stimulated mice massive inflammatory cells infiltrates surrounded the bronchioles, and miR-222-3p increased in the bronchoalveolar lavage fluid. In conclusion, miR-222-3p was highly expressed in children with MPP, especially those with pleural effusion.

Conclusion

Small sample studies showed that M.pneumoniae or its LAMPs could increase miR-222-3p and decrease CD4 in macrophages,both in vitro and vivo.Thus, miR-222-3p might be an MPP biomarker for the diagnosis and prognosis.

Plasma soluble B7-H3 levels for severity evaluation in pediatric patients with Mycoplasma pneumoniae pneumonia

Seeking for the novel biomarkers for Mycoplasma pneumoniae pneumonia (MPP) could be not only helpful for disease diagnosis but also useful for treatment efficacy monitoring. The aim of present study was to evaluate the role of plasma soluble B7-H3 (sB7-H3) in MPP diagnosis and treatment efficacy prediction, and involvement of B7-H3 in MPP disease course. A total of 108 MPP patients and 40 control subjects were recruited into this study for changes of sB7-H3 levels in MPP. In addition, a mouse model of MPP was also established for confirmation of the involvement of sB7-H3 in MPP in vivo. Significantly increased levels of sB7-H3 were found in both mild and severe MPP patients compared to control patients. Moreover, significantly increased level of sB7-H3 was also found in severe MPP patients compared to mild subjects. The ROC curve showed sB7-H3 had severity prediction capacity in mild and severe MPP. Plasma sB7-H3 correlated positively with IFN-r and GM-CSF in mild or severe MPP patients. Moreover, significantly increased level of plasma sB7-H3 level were found in acute phase MPP patients compared to control subjects, whereas significantly decreased level of plasma sB7-H3 was found in recovery phase MPP patients compared to acute phase patients. In addition, decreased levels of sB7-H3 were found in mice from Dexamethasone group compared to LAMP group. Plasma sB7-H3 level might serve as biomarker for severity MPP prediction and treatment efficacy evaluation. Furthermore, direct involvement of B7-H3 was confirmed in vivo during the MPP disease course.

Binding of IgA by Mycoplasma penetrans

The current study shows that Mycoplasma penetrans strain GTU binds human serum immunoglobulin A (IgA) and secretory IgA but not IgG. Binding of IgA was associated almost exclusively with the lipoprotein fraction obtained by Triton X-114 fractionation of isolated M. penetrans membranes. Western immunoblot analysis of isolated membranes of M. penetrans strain GTU and of the Triton X-114 fraction showed that the major IgA-binding component was a lipoprotein with a molecular mass of 38 kDa, one of the major lipoproteins of this organism. The authors suggest that the high IgA-binding capacity of M. penetrans strain GTU may serve as a defense mechanism, conferring on this microorganism the ability to evade clearance mediated by specific IgA antibodies.

Mycoplasma genitalium-derived lipid-associated membrane proteins induce activation of MAPKs, NF-kappaB and AP-1 in THP-1 cells

Mycoplasma genitalium lipid-associated membrane proteins (LAMPg) can induce human monocytic cell line THP-1 to produce proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), IL-1beta and IL-6, as demonstrated by an enzyme-linked immunosorbent assay and reverse transcription-PCR (RT-PCR). This study also investigated the signaling transduction pathways involved in the production of these cytokines. THP-1 cells were stimulated with LAMPg and then examined for the activation of MAPKs, such as SAPK/JNK, p38, extracellular signal-regulated kinase (ERK)1/2 and NF-kappaB and AP-1. Western blot clearly showed that stress-activated protein kinase (SAPK)/c-Jun-N-terminal kinase (JNK), p38 and ERK1/2 were activated in response to LAMPg, peaking at 30 min. SAPK/JNK-specific inhibitor SP600125 slightly suppressed IL-6 production although no evident effects were obtained for TNF-alpha and IL-1beta; ERK1/2 inhibitor PD98059 blocked both TNF-alpha and IL-1beta, but not IL-6 production. However, p38 inhibitor SB203580 abrogated TNF-alpha, IL-1beta and IL-6 production. The DNA-binding activity of NF-kappaB and AP-1 was also assessed by an electrophoretic mobility gel shift assay, and an NF-kappaB specific inhibitor, pyrrolidine dithiocarbamate, profoundly inhibited the synthesis and production of the proinflammatory cytokines. Based on these results, this study concludes that MAPKs, NF-kappaB and AP-1 may play important roles in the genital tract inflammatory reaction after mycoplasma infection.

Rapid and efficient preparation of monoclonal antibodies against 35 kDa lipoprotein of Mycoplasma penetrans

To develop a rapid and efficient method for preparing monoclonal antibodies (MAb) against 35 kDa lipoprotein of Mycoplasma penetrans, BALB/c mice were injected into the footpads for immunization, and the popliteal lymph nodes were isolated 19 days later for MAb-producing hybridomas, from which the mAbs against the 35 kDa lipoprotein were screened. The identification of the mAb against the 35 kDa lipoprotein was performed using indirect enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Using popliteal lymph node procedures, we generated several positive clones, one of which we characterized by ELISA and immunoblot. The clone 1D41B8 was identified as the immunoglobulin G1 (IgG1) isotype, kappa chain with affinity constants (Ka) of 2.95 x 10(9) M(-1). The MAbs did not cross-react with a number of control bacteria, which included Mycoplasma fermentans, Mycoplasma hominis, and Mycoplasma genitalium. This is the first report on the preparation of mAbs against M. penetrans that is specific to 35 kDa lipoprotein using popliteal lymph nodes. The high-specificity and high-affinity MAbs produced by two methodologies used of hybridomas provide a basis for further research on the pathogenesis and early diagnosis of M. penetrans. This simple approach may become a method of choice for the generation and production of MAbs in a short period of time.