Juhua Zhou

Amphipathic antibacterial agents using cationic methacrylic polymers with natural rosin as pendant group

We prepared a class of novel cationic polymers as antimicrobial agents: quaternary ammonium-containing poly(N,N-dimethylaminoethyl methacrylate) with natural rosin as the pendant group (PDMAEMA-g-rosin). Different from most other amphipathic antimicrobial polymeric systems reported in the literature, our approach sandwiched the hydrophilic cationic group between the polymer backbone and bulky hydrophobic hydrophenanthrene side groups. A simple quaternization reaction was used to link the rosin ester chloride and PDMAEMA homopolymers. Both the Gram-positive bacterium Staphylococcus aureus (S. aureus) and Gram-negative bacterium Escherichia coli (E. coli) were tested against the PDMAEMA-g-rosin copolymers. PDMAEMA-g-rosin copolymers with the amphipathic structure exhibited effective antimicrobial activity against both E. coli and S. aureus. Both the degree of quaternization of rosin group and the molecular weight of PDMAEMA played roles in antimicrobial activities. Our results also indicated that conformation of hydrophobic group (particularly steric hindrance) played a role in dictating antibacterial efficacy. Scanning electron microscopy and confocal laser scanning microscopy were used to characterize morphological changes of bacteria after exposure with PDMAEMA-g-rosin copolymers. Possible mechanisms on a combination of ionic and hydrophobic interactions between bacterial cells and polymers are discussed.

Dysregulation in microRNA expression is associated with alterations in immune functions in combat veterans with post-traumatic stress disorder.

While the immunological dysfunction in combat Veterans with post-traumatic stress disorder (PTSD) has been well documented, the precise mechanisms remain unclear. The current study evaluated the role of microRNA (miR) in immunological dysfunction associated with PTSD. The presence of peripheral blood mononuclear cells (PBMC) and various lymphocyte subsets in blood collected from PTSD patients were analyzed. Our studies demonstrated that the numbers of both PBMC and various lymphocyte subsets increased significantly in PTSD patients. When T cells were further analyzed, the percentage of Th1 cells and Th17 cells increased, regulatory T cells(Tregs) decreased, while Th2 cells remained unaltered in PTSD patients. These data correlated with increased plasma levels of IFN-γ and IL-17 while IL-4 showed no significant change. The increase in PBMC counts, Th1 and Th17 cells seen in PTSD patients correlated with the clinical scores. High-throughput analysis of PBMCs for 1163 miRs showed that the expression of a significant number of miRs was altered in PTSD patients. Pathway analysis of dysregulated miRs seen in PTSD patients revealed relationship between selected miRNAs and genes that showed direct/indirect role in immunological signaling pathways consistent with the immunological changes seen in these patients. Of interest was the down-regulation of miR-125a in PTSD, which specifically targeted IFN-γ production. Together, the current study demonstrates for the first time that PTSD was associated with significant alterations in miRNAs, which may promote pro-inflammatory cytokine profile. Such epigenetic events may provide useful tools to identify potential biomarkers for diagnosis, and facilitate therapy of PTSD.

Dysregulation in microRNA expression in peripheral blood mononuclear cells of sepsis patients is associated with immunopathology

Sepsis is a major cause of death worldwide. It triggers systemic inflammation, the role of which remains unclear. In the current study, we investigated the induction of microRNA (miRNA) during sepsis and their role in the regulation of inflammation. Patients, on days 1 and 5 following sepsis diagnosis, had reduced T cells but elevated monocytes. Plasma levels of IL-6, IL-8, IL-10 and MCP-1 dramatically increased in sepsis patients on day 1. T cells from sepsis patients differentiated primarily into Th2 cells, whereas regulatory T cells decreased. Analysis of 1163 miRNAs from PBMCs revealed that miR-182, miR-143, miR-145, miR-146a, miR-150, and miR-155 were dysregulated in sepsis patients. miR-146a downregulation correlated with increased IL-6 expression and monocyte proliferation. Bioinformatics analysis uncovered the immunological associations of dysregulated miRNAs with clinical disease. The current study demonstrates that miRNA dysregulation correlates with clinical manifestations and inflammation, and therefore remains a potential therapeutic target against sepsis.

Immune modulation by chondroitin sulfate and its degraded disaccharide product in the development of an experimental model of multiple sclerosis

Clinical symptoms in MOG-induced EAE mice significantly exacerbated following chondroitin sulfate A (CS-A) injection, whereas administration of a degraded product, CSPG-DS, caused dramatic inhibition of EAE development. Also, administration of CSPG-DS but not CS-A, after the onset of clinical symptoms of EAE, was able to suppress the disease. Further studies demonstrated that CS-A up-regulated STAT4 expression and thus, induced IFN-gamma production and Th1 CD4 T cell differentiation. CS-A also up-regulated STAT3 and IL-23 expression and thus increased IL-17 producing T cells. CSPG-DS treatment both in vivo and in vitro decreased TNFalpha production from splenocytes. In vitro and in vivo studies indicated that CSPG-DS treatment in EAE mice significantly blocked migration of lymphocytes, whereas CS-A treatment increased lymphocyte infiltration in the brain.

Evidence for Epigenetic Regulation of Pro-Inflammatory Cytokines, Interleukin-12 and Interferon Gamma, in Peripheral Blood Mononuclear Cells from PTSD Patients

While Post Traumatic Stress Disorder (PTSD) is associated with immune dysfunction, the underlying mechanisms remain unclear. Studies suggest a role for involvement of epigenetic mechanisms and microRNAs (miRNAs). Here, we examined genome-wide histone and DNA methylation in the peripheral blood mononuclear cells (PBMCs) in PTSD. We noted significant differences in histone H3 trimethylation at K4, K9, K27 and K36 sites in PTSD when compared to control. While overall DNA methylation level did not differ significantly between control and PTSD, the promoters of several individual genes (e.g., Interferon gamma (IFNG) and Interleukin (IL)-12B) were differentially methylated. ChIP-seq data revealed that the promoter of IFNG and TBX-21 was associated with the activation marker H3K4me3 in PTSD. The transcript levels of both IFNG and TBX-21 were higher in PTSD correlating well with the altered methylation patterns. Furthermore, PTSD patients showed increased expression of IL-12 in their PBMCs. Analysis of both histone and DNA methylation markers suggested that the expression of IL-12 was also possibly activated through epigenetic modification. Knockdown of lysine (K)-specific demethylase 5B (KDM5B), or inhibition of DNA (Cytosine-5-)-methyltransferase 1 (DNMT1) caused up-regulation of IL-12. Furthermore, the expression of these cytokines was also regulated by miRNAs. Our miRNA microarray identified many downregulated miRNAs in PTSD that are predicted to target IFNG and IL-12. Consequently, we showed that up-regulation of hsa-miR-193a-5p could decrease the expression of IL-12. Overall, the current study demonstrated that the elevated expression of pro-inflammatory cytokines in PTSD patients might be regulated by multiple epigenetic mechanisms and miRNAs.