Therapeutic Role for TSP-2 Antibody in a Murine Asthma Model.

BACKGROUND: Specific immunotherapy, including agonists for Toll-like receptor 2 (TLR2), have been shown to protect from allergies and to have a high immunomodulatory capacity. METHODS: A new antibody, TSP-2, reactive against an epitope of the extracellular domain of TLR2, was identified. The effect of the antibody on dendritic cells was assessed by immunohistochemistry, Western blot, and flow cytometric analysis. The effect of TSP-2 in a murine asthma model induced with ovalbumin (OVA) was assessed. The model is a form of airway hyperresponsiveness (AHR) and was analyzed by whole-body plethysmography, the measurement of Th1/Th2 cytokines in bronchial alveolar lavage fluid (BALF) and serum by ELISA, and the CCK-8 assay for lymphocyte proliferation. The effect of TSP-2 on the maturation of bone marrow-derived dendritic cells (BMDCs) was assessed by flow cytometric analysis. RESULTS: TSP-2 promoted the maturation of dendritic cells and the proliferation of lymphocyte in vitro and in vivo. The effect of TSP-2 on T helper 1 (Th1)/Th2 cytokine secretion was slightly more powerful than that of Pam3CSK4. TSP-2 antibody reduced AHR and OVA-specific IgE levels in allergic asthma. TSP-2 antibody also reduced lung inflammation and decreased leukocyte numbers in an OVA-sensitized and challenged asthma model. TSP-2 antibody increased OVA-stimulated I-A, CD80, CD86, and MHC-II levels on BMDCs. CONCLUSIONS: This study identifies a novel therapeutic strategy for AHR, which uses antibodies reactive against TLR2. It also provides theoretical evidence for the control of allergic asthma by targeting TLR2.

Rheb1 deletion in myeloid cells aggravates OVA-induced allergic inflammation in mice.

The small GTPase ras homolog enriched in brain (Rheb) is a downstream target of tuberous sclerosis complex 1/2 (TSC1/2) and an upstream activator of the mechanistic target of rapamycin complex 1 (mTORC1), the emerging essential modulator of M1/M2 balance in macrophages. However, the role and regulatory mechanisms of Rheb in macrophage polarization and allergic asthma are not known. In the present study, we utilized a mouse model with myeloid cell-specific deletion of the Rheb1 gene and an ovalbumin (OVA)-induced allergic asthma model to investigate the role of Rheb1 in allergic asthma and macrophage polarization. Increased activity of Rheb1 and mTORC1 was observed in myeloid cells of C57BL/6 mice with OVA-induced asthma. In an OVA-induced asthma model, Rheb1-KO mice demonstrated a more serious inflammatory response, more mucus production, enhanced airway hyper-responsiveness, and greater eosinophil numbers in bronchoalveolar lavage fluid (BALF). They also showed increased numbers of bone marrow macrophages and BALF myeloid cells, elevated M2 polarization and reduced M1 polarization of macrophages. Thus, we have established that Rheb1 is critical for the polarization of macrophages and inhibition of allergic asthma. Deletion of Rheb1 enhances M2 polarization but decreases M1 polarization in alveolar macrophages, leading to the aggravation of OVA-induced allergic asthma.

Neuronal mTORC1 Is Required for Maintaining the Nonreactive State of Astrocytes.

Astrocytes respond to CNS insults through reactive astrogliosis, but the underlying mechanisms are unclear. In this study, we show that inactivation of mechanistic target of rapamycin complex (mTORC1) signaling in postnatal neurons induces reactive astrogliosis in mice. Ablation of Raptor (an mTORC1-specific component) in postmitotic neurons abolished mTORC1 activity and produced neurons with smaller soma and fewer dendrites, resulting in microcephaly and aberrant behavior in adult mice. Interestingly, extensive astrogliosis without significant astrocyte proliferation and glial scar formation was observed in these mice. The inhibition of neuronal mTORC1 may activate astrogliosis by reducing neuron-derived fibroblast growth factor 2 (FGF-2), which might trigger FGF receptor signaling in astrocytes to maintain their nonreactive state, and FGF-2 injection successfully prevented astrogliosis in Raptor knock-out mice. This study demonstrates that neuronal mTORC1 inhibits reactive astrogliosis and plays an important role in CNS pathologies.

[Effect of TSP-2 antibody against a single epitope of mouse Toll-like receptor 2 extracellular domain on nuclear factor-kappa B and cytokine expression in the intestine of septic mice].

OBJECTIVE: To observe the effect of the antibody TSP-2 against a single epitope of mouse Toll-like receptor 2 extracellular domain (mTLR2ECD) on the expression of nuclear factor-kappa B (NF-κB) and cytokines in the intestinal tissue of septic mice. METHODS: Male BALB/c mice were randomly divided into 4 groups, namely the sham-operated group, model group, TSP-2 treatment group and rabbit IgG treatment group. Sepsis was induced by cecal ligation and puncture (CLP), and at 6, 12 or 24 h after the operation, the ileal tissues were harvested from the mice for HE staining. NF-κB expression was detected with immunohistochemistry. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) mRNA expressions were detected with qRT-PCR and their protein expressions by ELISA. RESULTS: The NF-κB expression in the intestinal tissue significantly increased in the model group as compared with that in the sham- operated group, and decreased after TSP-2 treatment. The model group also showed significantly increased expression levels of TNF-α and IL-6 mRNA and protein in the intestinal tissue (P<0.05), which were lowered by TSP-2 (P<0.05) but not by rabbit IgG treatment (P>0.05). CONCLUSION: The TSP-2 antibody can protect the intestine and delay the development of sepsis by inhibiting NF-κB activation and down-regulating TNF-α and IL-6 expressions in mice.

[Effect of TSP-2 antibody against a single epitope of mouse Toll-like receptor 2 extracellular domain on zymosan A-induced peritonitis in mice].

OBJECTIVE: To observe the effect of the antibody TSP-2 against a single epitope of mouse Toll-like receptor 2 extracellular domain (mTLR2ECD) on the inflammation in mice with zymosan A-induced peritonitis. METHODS: In mice with peritonitis induced by intraperitoneal injection of zymosan A, pretreatments with PBS, normal rabbit IgG and TSP-2 antibody at two different doses (2.5 and 5.0 mg/kg) were administered via the tail vein. Six hours after intraperitoneal injection of zymosan A, Evans blue was injected through the tail vein, and the frequency of writhing of the mice within 20 min were recorded. The mice were then sacrificed for peritoneal lavage, and the lavage fluid was collected to assess the exudation of Evans blue in the supernatant. The peritoneal leukocyte count, mast cell degranulation and release of such inflammatory mediators as platelet activating factor (PAF) and tumor necrosis factor-alpha (TNFalpha) in the lavage fluid were observed by cell counting, specific cell staining, immunohistochemistry and enzyme-linked immunosorbent assay (ELISA). RESULTS: Compared with PBS or rabbit IgG groups, TSP-2 treatment resulted in significantly reduced writhing response of the mice and lowered Evans blue exudation and leukocyte count in the peritoneal lavage, with also decreased degranulation of the mast cells induced by C48/80. CONCLUSION: TSP-2 antibody against a single epitope of mTLR2ECD inhibits the inflammatory response in mice with zymosan A-induced peritonitis.

[One-step multiplex RT-PCR for rapid screening of type A, B and novel A (H1N1) influenza viruses].

OBJECTIVE: To developed a multiplex RT-PCR assay for simultaneous screening of type A, B and novel A (H1N1) influenza viruses. METHODS: Two pairs of universal primers in were designed for amplifying the M gene and NS gene of type A and B influenza viruses, respectively. A pair of specific primers of HA gene was designed to detect novel A (H1N1) influenza virus. A one-step method was used to establish the multiplex RT-PCR system. A blinded experiment was carried out to validate the accuracy of this assay in comparison with the results of real-time fluorescence RT-PCR. The clinical practicability and efficacy of this assay was also evaluated. RESULTS: The RT-PCR products were analyzed using agarose gel electrophoresis, which yielded distinct bands of the target fragments without non-specific reactions, suggesting the high efficiency and specificity of the multiplex RT-PCR. Blinded study of 50 samples demonstrated a concordance rate of 100%. CONCLUSION: This multiplex RT-PCR assay allows one-step simultaneous detection of type A, B and novel A (H1N1) influenza viruses rapidly and accurately, and provides a valuable low-cost screening technique for influenza epidemic monitoring and early diagnosis.

[Cloning and expression of murine Toll-like receptor-2 N terminal and preparation of its antibody].

OBJECTIVE: To prepare the recombinant murine Toll-like receptor-2 N-terminal (mTLR-2N) fusion protein and obtain anti-mTLR-2N polyclonal antibody. METHODS: The gene encoding 153 amino acids of mTLR-2N was amplified by PCR and cloned into pET32A vector with sequence verification. The recombinant fusion protein was expressed in E. coli and purified by Probond resin column. Rabbits were immunized with fusion protein to obtain the polyclonal anti-sera, and the antibodies were identified by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. RESULTS: The recombinant fusion protein was efficiently expressed and purified. The polyclonal antibodies could bind to the fusion protein expressed in different vectors as the antigens in ELISA, and also bind with RAW264.7 cells expressing mTLR-2 and CHO cells transfected with full-length mTLR-2 gene. CONCLUSION: The recombinant mTLR-2N fusion protein is obtained and the anti-mTLR-2N polyclonal antibody can recognize natural mTLR-2 on the cell surface.