PLGA-Chitosan Encapsulated IL-10 Nanoparticles Modulate Chlamydia Inflammation in Mice

Introduction

Interleukin-10 (IL-10) is a key anti-inflammatory mediator in protecting host from over-exuberant responses to pathogens and play important roles in wound healing, autoimmunity, cancer, and homeostasis. However, its application as a therapeutic agent for biomedical applications has been limited due to its short biological half-life. Therefore, it is important to prolong the half-life of IL-10 to replace the current therapeutic application, which relies on administering large and repeated dosages. Therefore, not a cost-effective approach. Thus, studies that aim to address this type of challenges are always in need.

Methods

Recombinant IL-10 was encapsulated in biodegradable nanoparticles (Poly-(Lactic-co-Glycolic Acid) and Chitosan)) by the double emulsion method and then characterized for size, surface charge, thermal stability, cytotoxicity, in vitro release, UV-visible spectroscopy, and Fourier Transform-Infrared Spectroscopy as well as evaluated for its anti-inflammatory effects. Bioactivity of encapsulated IL-10 was evaluated in vitro using J774A.1 macrophage cell-line and in vivo using BALB/c mice. Inflammatory cytokines (IL-6 and TNF-α) were quantified from culture supernatants using specific enzyme-linked immunosorbent assay (ELISA), and significance was analyzed using ANOVA.

Results

We obtained a high 96% encapsulation efficiency with smooth encapsulated IL-10 nanoparticles of ~100-150 nm size and release from nanoparticles as measurable to 22 days. Our result demonstrated that encapsulated IL-10 was biocompatible and functional by reducing the inflammatory responses induced by LPS in macrophages. Of significance, we also proved the functionality of encapsulated IL-10 by its capacity to reduce inflammation in BALB/c mice as provoked by Chlamydia trachomatis, an inflammatory sexually transmitted infectious bacterium.

Discussion

Collectively, our results show the successful IL-10 encapsulation, slow release to prolong its biological half-life and reduce inflammatory cytokines IL-6 and TNF production in vitro and in mice. Our results serve as proof of concept to further explore the therapeutic prospective of encapsulated IL-10 for biomedical applications, including inflammatory diseases.

Chlamydia trachomatis recombinant MOMP encapsulated in PLGA nanoparticles triggers primarily T helper 1 cellular and antibody immune responses in mice: a desirable candidate nanovaccine

We recently demonstrated by in vitro experiments that PLGA (poly D, L-lactide-co-glycolide) potentiates T helper 1 (Th1) immune responses induced by a peptide derived from the recombinant major outer membrane protein (rMOMP) of Chlamydia trachomatis, and may be a promising vaccine delivery system. Herein we evaluated the immune-potentiating potential of PLGA by encapsulating the full-length rMOMP (PLGA-rMOMP), characterizing it in vitro, and investigating its immunogenicity in vivo. Our hypothesis was that PLGA-rMOMP triggers Th1 immune responses in mice, which are desirable prerequisites for a C. trachomatis candidate nanovaccine. Physical-structural characterizations of PLGA-rMOMP revealed its size (approximately 272 nm), zeta potential (−14.30 mV), apparent spherical smooth morphology, and continuous slow release pattern. PLGA potentiated the ability of encapsulated rMOMP to trigger production of cytokines and chemokines by mouse J774 macrophages. Flow cytometric analyses revealed that spleen cells from BALB/c mice immunized with PLGA-rMOMP had elevated numbers of CD4+ and CD8+ T cell subsets, and secreted more rMOMP-specific interferon-gamma (Th1) and interleukin (IL)-12p40 (Th1/Th17) than IL-4 and IL-10 (Th2) cytokines. PLGA-rMOMP-immunized mice produced higher serum immunoglobulin (Ig)G and IgG2a (Th1) than IgG1 (Th2) rMOMP-specific antibodies. Notably, sera from PLGA-rMOMP-immunized mice had a 64-fold higher Th1 than Th2 antibody titer, whereas mice immunized with rMOMP in Freund’s adjuvant had only a four-fold higher Th1 than Th2 antibody titer, suggesting primarily induction of a Th1 antibody response in PLGA-rMOMP-immunized mice. Our data underscore PLGA as an effective delivery system for a C. trachomatis vaccine. The capacity of PLGA-rMOMP to trigger primarily Th1 immune responses in mice promotes it as a highly desirable candidate nanovaccine against C. trachomatis.

Naringenin: an immunomodulator of Interleukin (IL)-6, IL-8, and Tumor Necrosis Factor secretion from Chlamydia trachomatis-infected macrophages and epithelial cells (110.28)

Chlamydia trachomatis, the leading cause of bacterial sexually transmitted infections, is responsible for a myriad of immunopathological changes associated with reproductive health. Chlamydia infects macrophages and epithelial cells, which secrete cytokines such as TNF, IL-6 and IL-8 that are key protagonists of acute inflammation. These cytokines put the patient at risk for major health issues such as pelvic inflammatory disease and infertility if not controlled. Counterbalancing their levels helps mitigate acute inflammation. We have shown that IL-10 regulates inflammatory cytokines elicited by C. trahomatis in innate immune cells. Here we explored the hypothesis that Naringenin, a natural flavonone, with anti-inflammatory properties, when used alone or co-cultured with IL-10 will modulate inflammatory cytokines secreted from C. trachomatis-infected epithelial (HeLa) cells and mouse J774 macrophages. We exposed C. trachomatis-infected cells to Naringenin (100, 10, 1, 0.1, and 0.01 μg/mL) alone or with IL-10 (10 ng/mL). Our results as demonstrated using cytokine ELISA, confocal microscopy and MTT assay, indicate that Naringenin abrogated TNF, IL-8, and IL-6 levels in a dose-dependent fashion. Cytokine levels were reduced further by Naringenin co-cultured with IL-10. The MTT assay showed the anti-inflammatory effect of Naringenin was not due to cell death. The data provides evidence for a novel therapeutic direction in controlling C. trachomatis-induced acute inflammation.

Expression and characterization of a multivalent human respiratory syncytial virus protein

Respiratory syncytial virus (RSV) has been recognized as one of the most common causes of severe respiratory tract infection in infants worldwide. As yet, a safe and effective vaccine has not been developed to protect humans from RSV. The F and G surface proteins have been widely investigated due to their potential to induce protective immunity. In addition, the M2 protein has been shown to be important in inducing a T-cell response. Our project involved the cloning of the immunodominant regions of the RSV F, M2 and G proteins into a bacterial vector, pET-32a (+). The recombinant RFM2G protein was expressed in Escherichia coli and purified using His Bind columns. The purified rRFM2G protein was analyzed by polyacrylamide gel electrophoresis and Western blotting. The predicted structure of the recombinant protein built by the Swiss PDB Viewer program suggested a rod shape with a distinct swollen head and neck which was confirmed by transmission electron microscopy and atomic force microscopy. BALB/c female mice were immunized with either RSV, rRFM2G alone, or rRFM2G in combination with flagellin as a mucosal adjuvant. Serum was collected on days 0, 14, 28 and 49 to assess the immune response by Enzyme-linked immunosorbent assay. Intranasal immunization of mice with the rRFM2G protein yielded significantly high serum IgG titers. Co-administration of the rRFM2G protein with flagellin did not augment the serum antibody response.

Characterization and the Immune Response of a Nanoencapsulated Multivalent Vaccine against Respiratory Syncytial Virus (132.2)

Development of a safe and effective vaccine is necessary to prevent RSV infection. Our project involved development of a multivalent vaccine for RSV by amplification of the antigenic regions of the RSV F, G and M2 genes which were subsequently cloned into a bacterial vector, pET-32. The recombinant clone was expressed from the transformed E. coli BL21 (DE3) cells purified and analyzed yielding a protein band of 38 kDa as predicted. The multivalent protein was encapsulated in chitosan to form protein encapsulated nanoparticle using the incorporation method. The encapsulated nanoparticles were analyzed for temperature stability, in vitro release of the protein, and also characterized using cytoviva bioimaging system as well as FTIR. The nanoencapsulated protein was stable up to a temperature of 1100C. The cytoviva bioimaging system revealed that the nanoparticles were irregular spherical shaped and the protein encapsulated nanoparticle appeared to be larger compared to the chitosan alone. The FTIR confirmed the chemical composition of the nanoparticle which consisted of polysaccharide, tripolyphosphate and protein. BALB/c female mice were immunized with the nanoencapsulated multivalent protein and the antibody response was compared to the mice vaccinated with live RSV or PBS The serum antibody response data revealed that mice immunized with the nanoencapsulated vaccine had the highest levels of antibody against RSV.

Keywords: RSV, Antibody, Vaccine, Recombinant DNA, Chitosan nanoparticle.

Sponsors: NSF-CREST, NIH-MBRS

HL 752: a potent and long-acting antispasmodic agent

Ester analogues of methyl-2-(4-(2-piperidinoethoxy)benzoyl)-benzoate hydrochloride (pitofenone) (2) were prepared with an aim to find a more potent and metabolically stable antispasmodic compound. The compounds were evaluated for their in vitro and in vivo antispasmodic activity, and stability to in vitro enzymatic hydrolysis. Of the compounds synthesised, HL 752 (21) showed the most potent and long-lasting antispasmodic activity and was selected as the candidate for clinical development.

Cardiotonic activity of the water soluble forskolin derivative 8,13-epoxy-6 beta-(piperidinoacetoxy)- 1 alpha, 7 beta, 9 alpha-trihydroxy-labd- 14en-11-one

8,13-Epoxy-6 beta-(piperidinoacetoxy)-1 alpha,7 beta, 9 alpha-trihydroxy-labd -14en-11-one (HL 706, CAS 114376-11-3) is a water soluble derivative of forskolin with positive inotropic and vasodilating properties. In both in vitro and in vivo preparations, it exhibited significant positive inotropic activity with concomitant increase in heart rate and decrease in mean blood pressure. Though its potency is lower than that of forskolin, its duration of action is more prolonged. In conscious dog experiments, HL 706, administered orally, also showed a dose related increase in LV dP/dtmax. A significant reversal of cardiac failure was attained in anaesthetised dogs subjected to propranolol induced cardiac insufficiency. HL 706, like forskolin increased cAMP by virtue of its adenylate cyclase stimulant activity. Through increase in cAMP it also exhibited non-specific smooth muscle relaxant activity in isolated vascular and ileal preparations. Its therapeutic ratio is quite favourable.