Infection with Chlamydia Pneumoniae in Neuronal Cells Alters the Expression of Genes Involved in Apoptosis and Autophagy Pathways

Dysfunctions in cellular mechanisms such as apoptosis and autophagy have been implicated in the neurodegeneration associated with Alzheimer’s disease (AD). Autophagy in AD pathogenesis has been linked to the endosomal-lysosomal system, which has been shown to play a role in amyloid processing. Studies have suggested that apoptosis may contribute to the neuronal cell loss observed in AD; however, there is no evidence of the apoptotic process leading to terminal completion. Aβ1-42 has been shown to induce apoptosis in neurons and may be an initiating factor in AD. Our previous studies demonstrated that neurons infected with C. pneumoniae are resistant to apoptosis, and that Aβ1-42 was increased by the infection. Additionally, studies have demonstrated the interactions of several pathogens on the autophagic pathway. The focus of the current studies was to determine if there is a relationship between the molecular mechanisms interconnecting autophagy and apoptosis following C. pneumoniae infection in neuronal cells that could lead to the pathologies observed in AD. SKNMC neuronal cells obtained from ATCC were infected with the AR39 strain of C. pneumoniae at an MOI=1 for 24hrs to 72hrs and were analyzed using Real-time PCR arrays from SABiosciences specific for autophagy and apoptosis markers. At 24hrs, neuronal cells infected with C. pneumoniae resulted in down-regulation of apoptosis and autophagy gene regulation. Neuronal cells infected at 72hrs with C. pneumoniae up-regulated the expression of several genes associated with autophagy and apoptosis. For example, BECN1 and ATG4C, both prominent genes in the autophagy pathway were 3.66 to 25.77 fold down-regulated at 24hrs and increased 1.53 to 1.73 fold 72hrs post-infection, iv respectively. Similarly, apoptosis gene expression such as that for BAK1 was increased from -1.15 fold at 24hrs to 2.09 fold at 72hrs post-infection. Our data suggest that C. pneumoniae exerts a control over changes in gene regulation affecting the apoptotic and autophagic processes in neuronal cells. As both autophagic and apoptosis dysfunction have been observed in AD, the impairment of these normal cellular processes by a pathogen such as C. pneumoniae may contribute to the neuropathology seen in AD

Effect of functionalization of polymeric nanoparticles incorporated with whole attenuated rabies virus antigen on sustained release and efficacy

AbstractNanovaccines introduced a new dimension to prevent or cure diseases in an efficient and sustained manner. Various polymers have been used for the drug delivery to increase the therapeutic value with minimal side effects. Thus the present study incorporates both nanotechnology and polymers for the drug delivery. Poly(d,l-lactic-co-glycolic acid)-b-poly(ethylene glycol) was incorporated with the rabies whole attenuated viral antigen using double emulsion (W/O/W) method and characterized by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Chitosan-PEG nanoparticles incorporated with the rabies whole attenuated virus antigen (CS-PEG NP-RV Ag.) were prepared using Ionic Gelation method. The CS-PEG NP-RV Ag. was surface modified with biocompatible polymers such as Acacia, Bovine Serum Albumin (BSA), Casein, Ovalbumin and Starch by Ionic Gelation method. The morphology was confirmed by SEM and Transmission Electron Microscopy (TEM). The surface modification was confirmed by Fourier Transform Infrared Spectroscopy (FTIR), Zeta potential. The size distribution of CS-PEG-RV Ag. and surface modified CS-PEG-RV Ag. by respective biocompatible polymers was assessed by Zetasizer. Release profile of both stabilized nanoparticles was carried out by modified centrifugal ultrafiltration method which showed the sustained release pattern of the Rabies Ag. Immune stimulation under in-vitro condition was studied using rosette assay and phagocytosis assay. In-vitro toxicity using human blood and genotoxicity using human blood DNA was also studied to assess the toxicity of the nanoformulations. The results of these studies infer that PLGA-b-PEG nanoparticles, CS-PEG and surface modified CS-PEG nanoparticles may be an efficient nanocarrier for the RV Ag. to elicit immune response sustainably with negligible toxic effect to the human system