Increase of intermediate forms of beta-N-acetylhexosaminidase during rat liver development and regeneration

Purification and biochemical/biophysical characterization of two hexosaminidases from the fresh water mussel, Lamellidens corrianus

Two thermostable isoforms of a hexosaminidase were purified to homogeneity from the soluble extract of fresh water mussel Lamellidens corrianus, employing a variety of chromatographic techniques. Hexosaminidase A (HexA) is a heterodimer with subunit masses of ~80 and 55 kDa. Hexosaminidase B (HexB) is a homodimer with a subunit mass of 55-60 kDa. Circular dichroism spectroscopic studies indicated that both HexA and HexB contain β-sheet as the major secondary structural component with considerably lower content of α-helix. The temperature and pH optima of both the isoforms were found to be 60 °C and 4.0, respectively. The IC₅₀ values for HexA with N-acetyl-d-galactosamine, N-acetyl-d-glucosamine, d-galactosamine, d-glucosamine, methyl α-d-mannopyranoside and d-mannose are 3.7, 72.8, 307, 216, 244 and 128 mM, respectively, whereas the corresponding IC₅₀ values for HexB were estimated as 5.1, 61, 68, 190, 92 and 133 mM, respectively. Kinetic parameters K_M and V_max for HexA and B with p-nitrophenyl N-acetyl-β-d-glucosaminide are 4 mM, 0.23 μmol·min^-1·mL^-1 and 2.86 mM, 0.29 μmol·min^-1·mL^-1, respectively, and with p-nitrophenyl N-acetyl-β-d-galactosaminide are 4.5 mM, 0.054 μmol·min^-1·mL^-1 and 1.4 mM, 0.14 μmol·min^-1·mL^-1, respectively. GalNAc inhibited both isoforms in a non-competitive manner, whereas a mixed mode of inhibition was observed with GlcNAc with both forms.

Evaluation of in vitro and in vivo anti-inflammatory activity of biologically active phospholipids with anti-neoplastic potential in porcine model

Background

This study aims to investigate the anti-inflammatory effect of biologically active phospholipids (BAP) used in preparations for clinical practice in humans. Until date, except anti-neoplastic ability, little is known about anti-inflammatory property of the phospholipids.

Methods

While the course of bacterially induced acute pneumonia and markers of inflammation were studied in in vivo system in pigs orally supplemented with BAP, the pro- and anti-inflammatory response of lipopolysaccharide-stimulated porcine monocyte-derived macrophages to 24 h- and 48 h-treatmeant by BAP was investigated in in vitro system. In vivo, the animal health status was monitored and pro-inflammatory IL-1β and IL-8 in sera were detected by ELISA during the experiment, while bronchoalveolar lavage fluids (BALF) and the lungs were examined post-mortem. Total and differential counts of white blood cell (WBC) were determined in blood and BALF. In vitro, mRNA expression of pro-inflammatory (TNF-α, IL-1β, CXCL10) and anti-inflammatory (IL-10 and Arg1) cytokines, and level of activated caspase 1 and phosphorylated protein kinase C epsilon (pPKCϵ), were studied using qRT-PCR and Western blot, respectively. For the purposes of both systems, 6 animals were used in each of the BAP-supplemented and the control groups.

Results

In vivo, BAP had a positive influence on the course of the disease. The immunomodulatory effects of BAP were confirmed by lower levels of IL-1β, IL-8, and a lower WBC count in the supplemented group in comparison with the control group. A lower percentage of lung parenchyma was affected in the supplemented group comparing to the control group (on average, 4% and 34% of tissue, respectively). In vitro, BAP suppressed mRNA expression of mRNA for IL-10 and all pro-inflammatory cytokines tested. This down-regulation was dose- and time-dependent. Arg1 mRNA expression remained unaffected. Further dose- and time-dependent suppression of the activated caspase 1 and pPKCϵ was detected in macrophages when treated with BAP.

Conclusions

Our results demonstrate that BAP has anti-inflammatory and immunomodulatory properties, thus emphasizing the potential of this compound as a natural healing agent.

Pregnancy modulates the expression of beta-N-acetylhexosaminidase in rat serum and tissues

1. beta-N-Acetylhexosaminidases in maternal rat serum were separated by DEAE-cellulose chromatography and compared with those of adult rat serum. 2. In pregnant serum there is an increase of the isoenzymes which are entirely composed of beta-subunits (B and intermediate forms). 3. These alterations could be compared to those already described in human pregnancy. 4. The levels of beta-N-acetylhexosaminidase and the relative expression of alpha- and beta-subunits in normal and pregnant serum correlate with the above isoenzyme expression. 5. The increase of B and intermediate forms as well as the increase of specific activity during pregnancy was not peculiar to maternal serum but was also demonstrated in several foetal tissues and in maternal tissues, in which cases the beta-N-acetylhexosaminidase isoenzyme patterns closely resemble the foetal ones rather than those of the adult rat tissues. 6. These analogies strongly suggest that the expression of beta-subunit of beta-N-acetylhexosaminidase is regulated by hormones or other factors related to pregnancy.