Treatment of Donor Rat Hearts Prior to Transplantation with FLIP (FADD-Like Interleukin Beta-Converting Enzyme (FLICE)-Like Inhibitory Protein) in Cardioplegic Solution Decreased Apoptosis at Thirty Minutes Post-transplantation and Decreased Total Tyrosine Phosphorylation Levels.

BACKGROUND Heart transplantation is a therapeutic option for patients with severe coronary artery disease or heart failure. One of the difficulties to overcome is the apoptosis of cardiomyocytes in the donor organ. To prevent apoptosis in the donor organ, we developed a fusion protein containing FLIP (FADD-like interleukin beta-converting enzyme (FLICE)-like inhibitory protein) to inhibit caspase-8. MATERIAL AND METHODS We linked the cDNA coding for the FLIP protein to the transduction domain of HIV (human immunodeficiency virus) to allow the protein to enter cells. The recombinant protein was used at two different concentrations, 3 nM and 30 nM, for treatment of the donor heart in rat transplantation experiments. After transplantation, apoptosis was measured by ELISA, and the levels of active caspase-3, caspase-8, Bid, and PUMA were determined by western blotting using specific antibodies. RESULTS We observed that treatment of the donor organ with a solution containing this protein reduced the apoptosis level in the donor organ after 30 minutes post-transplantation as measured by the total of apoptotic cells with ELISA assay, and caspase-8 and caspase-3 activation and decreased levels of BH3-only proteins such as Bid and PUMA. Furthermore, this treatment also reduced the total tyrosine phosphorylation levels, which may be a possible measurement of lower oxidative stress levels in cardiomyocytes. CONCLUSIONS Protein FLIP solution reduced apoptosis at 30 minutes post-transplantation and decreased levels of several regulators of apoptosis.

Red cell glycolytic enzyme disorders caused by mutations: an update.

Glycolysis is one of the principle pathways of ATP generation in cells and is present in all cell tissues; in erythrocytes, glycolysis is the only pathway for ATP synthesis since mature red cells lack the internal structures necessary to produce the energy vital for life. Red cell deficiencies have been detected in all erythrocyte glycolytic pathways, although their frequencies differ owing to diverse causes, such as the affected enzyme and severity of clinical manifestations. The number of enzyme deficiencies known is endless. The most frequent glycolysis abnormality is pyruvate kinase deficiency, since around 500 cases are known, the first of which was reported in 1961. However, only approximately 200 cases were due to mutations. In contrast, only one case of phosphoglycerate mutase BB type mutation, described in 2003, has been detected. Most mutations are located in the coding sequences of genes, while others, missense, deletions, insertions, splice defects, premature stop codons and promoter mutations, are also frequent. Understanding of the crystal structure of enzymes permits molecular modelling studies which, in turn, reveal how mutations can affect enzyme structure and function.

Two new phosphoglycerate kinase mutations associated with chronic haemolytic anaemia and neurological dysfunction in two patients from Spain.

We report two previously undescribed mutations of the phosphoglycerate kinase gene (PGK1) leading to enzyme deficiency. In both cases, the patients were of Spanish origin and they exhibited a severe life-long chronic haemolytic anaemia associated with progressive neurological impairment. Sequence analysis of the first patient's entire PGK1 gene found a novel missense mutation (140T > A). This mutation caused an amino acid change of Ile to Asn at 46th position from the NH(2)-terminal serine residue (Ile46Asn), which has been called PGK-Barcelona based on the place of origin of the patient. In the second patient, a G to A transversion was discovered at nucleotide 958 (958G > A). This caused a Ser319Asn amino acid substitution. Since this mutation had not been previously described, the provisional name of PGK-Murcia was given to this deficient enzyme. The crystal structure of porcine PGK was used as a molecular model to investigate how these mutations may affect enzyme structure and function. In both cases, the mutations did not modify any of the PGK binding sites for ATP or 3PG, so their consequence is related to a loss of enzyme stability rather than a decrease of enzyme catalytic function.

Effects of thyroid hormone and hypoxia on 2,3-bisphosphoglycerate, bisphosphoglycerate synthase and phosphoglycerate mutase in rabbit erythroblasts and reticulocytes in vivo.

OBJECTIVES: The effects of triiodothyronine (T(3)) and hypoxia on 2,3-bisphosphoglycerate (2,3-BPG) studied in vitro are unclear. To clarify these effects we selected a more physiologic approach: the in vivo study in rabbits. We also present the changes produced by T(3) and hypoxia on phosphoglycerate mutase (PGAM), which requires 2,3-BPG as a cofactor, and 2,3-BPG synthase (BPGS), the enzyme responsible for 2,3-BPG synthesis in erythroblasts and reticulocytes. METHODS: Hyperthyroidism was induced by daily T(3) injection (250 microg/kg), hypoxia by a mixture of 90% nitrogen and 10% oxygen and hypothyroidism by propylthiouracil (PTU) added to drinking water. RESULTS: Both T(3) administration and hypoxic conditions increased 2,3-BPG levels and BPGS mRNA levels and activity in erythroblasts but not in reticulocytes. Unlike BPGS, both PGAM mRNA levels and activity were increased in erythroblasts and reticulocytes under hyperthyrodism and hypoxia. The antihormone PTU produced opposite effects to T(3). CONCLUSION: The results presented here suggest that both hyperthyroidism and hypoxia modulate in vivo red cell 2,3-BPG content by changes in the expression of BPGS. Similarly, the changes in PGAM activity are also explained by changes in its expression.