Inflammation reduction potential of nanostructured lipid carriers encapsulated with rat's bone marrow cells' lysate.

Bone marrow-derived mesenchymal stromal cells (BMSCs) have been used for treating inflammatory disorders. Due to the large size of BMSCs compared to nanoparticles, BMSCs cannot be loaded into the nanoparticles. It is hypothesized that BMSCs lysate loading into the nanocarriers will effectively deliver cellular contents and regulatory elements of BMSCs at the injury site. This study aimed to investigate nanostructured lipid carriers (NLC) loading with BMSCs lysate through basic characterization and morphological analysis. Moreover, this study was mainly designed to investigate the role of NLC loaded BMSCs lysate in reducing inflammation via in-vitro and in-vivoassays. The in-vitro study involves cell viability assays, p53, annexin V and VEGF expression through ELISA and immunocytochemistry, real-time BAX, caspase-3, IL-6, IL-8, TOP2A, PCNA, and Ki-67 gene expression analysis. Additionally, to evaluate in-vivo anti-inflammatory activity, the carrageenan-induced rat paw oedema model was used. In-vitro results showed that NLC loaded BMSCs lysate increased cell viability, decreased apoptosis and pro-inflammatory genes expression and up-regulated angiogenesis and proliferation in H2O2 pre-stimulated cells. Findings of the in-vivo assay also indicated a reduction in rat's paw oedema volume in NLC-loaded BMSCs lysate, and downregulation of BAX, Caspase-3, IL-6, and IL-8 was observed. Enhanced expressions of TOP2A, PCNA, and Ki-67 were obtained. Concluding the results of this study, NLC-loaded BMSCs lysate could reduce inflammation and possibly regenerate damaged tissue mainly via increasing cell viability, angiogenesis and proliferation, and reducing apoptosis and pro-inflammatory cytokines.

Reconstitution of the holoenzyme form of Escherichia coli porphobilinogen deaminase from apoenzyme with porphobilinogen and preuroporphyrinogen: a study using circular dichroism spectroscopy.

Porphobilinogen deaminase (PBG-D), an early enzyme of the tetrapyrrole biosynthetic pathway, catalyzes the formation of a tetrapyrrole chain, preuroporphyrinogen, from four molecules of porphobilinogen (PBG). The PBG-D apoenzyme is responsible for the autocatalytic synthesis and covalent attachment of a dipyrromethane cofactor at its active site. In this paper an efficient method for the purification of Escherichia coli PBG-D apoenzyme using an affinity chromatography resin is reported. Circular dichroism (CD) spectra of apoenzyme and holoenzyme were recorded and significant differences in both the backbone and aromatic region of the spectra were observed. The differences in the spectra allowed the reconstitution of holoenzyme from purified apoenzyme with PBG and preuroporphyrinogen in solution to be monitored separately by CD. Apoenzyme incubated with preuroporhyrinogen gave a CD spectrum that was much more like the CD spectrum of holoenzyme than apoenzyme incubated with PBG. The results showed clearly that the cofactor was generated much more rapidly from preuroporphyrinogen than from PBG. Changes in the CD spectrum associated with the aromatic side-chain region, in particular the contribution assigned to phenylalanine-62, were found to correlate well with the activity of the reconstituted enzyme. Phenylalanine-62 is located in close proximity to the cofactor and acts as a sensitive probe to active-site changes. The stability of the holoenzyme and apoenzyme were compared with respect to both heat and susceptibility to proteolysis. The results were consistent with a model for the apoenzyme in which, in the absence of the cofactor, the three domains of the protein are held less rigidly together, thereby making the protein more susceptible to heat denaturation and proteolysis. The CD spectrum of the holoenzyme was found to be similar at both pH 5.1 and 7.4, suggesting that the crystal structure, determined at pH 5.1, is likely to be similar at physiological pH values.

Siroheme biosynthesis in higher plants. Analysis of an S-adenosyl-L-methionine-dependent uroporphyrinogen III methyltransferase from Arabidopsis thaliana.

Siroheme, the prosthetic group for both nitrite and sulfite reductases, is a methylated, iron-containing modified tetrapyrrole. Here we report the first molecular characterization of the branch point enzyme in higher plants, which directs intermediates toward siroheme synthesis. A cDNA was cloned from Arabidopsis thaliana (UPM1) that functionally complements an Escherichia coli cysG mutant, a strain that is unable to catalyze the conversion of uroporphyrinogen III (Uro'gen-III) to siroheme. UPM1 is 1484 base pairs and encodes a 369-amino acid, 39.9-kDa protein. The UPM1 product contains two regions that are identical to consensus sequences found in bacterial Uro'gen-III and precorrin methyltransferases. Recombinant UPM1 protein was found to catalyze S-adenosyl-L-methionine-dependent transmethylation by UPM1 in a multistep process involving the formation of a covalently linked complex with S-adenosyl-L-methionine. The UPM1 product has a sequence at the amino terminus that resembles a transit peptide for localization to mitochondria or plastids. The protein produced by in vitro expression is able to enter isolated intact chloroplasts but not mitochondria. Genomic blot analysis showed that UPM1 is encoded in the A. thaliana genome. The genomic DNA corresponding to UPM1 was cloned and sequenced and found to contain at least five introns.

Discovery that the assembly of the dipyrromethane cofactor of porphobilinogen deaminase holoenzyme proceeds initially by the reaction of preuroporphyrinogen with the apoenzyme.

The assembly process of the dipyrromethane cofactor of Escherichia coli porphobilinogen deaminase holoenzyme is initiated by the reaction of the porphobilinogen deaminase apoenzyme with preuroporphyrinogen. The resulting enzyme-bound tetrapyrrole (bilane) is equivalent to the holoenzyme intermediate complex ES2 and yields the dipyrromethane cofactor by reactions of the normal catalytic cycle. These observations indicate that preuroporphyrinogen, rather than porphobilinogen, is the preferred precursor for the dipyrromethane cofactor and explain the existence of the D84A and D84N deaminase mutants as catalytically inactive ES2 complexes.