Az orvos-, egészségtudományi- és gyógyszerészképzés tudományos műhelyeinek fejlesztése(EFOP-3.6.3-VEKOP-16-2017-00009)
Támogató: EFOP-VEKOP
Human placenta is an intensively growing tissue. Phosphatidylinositol (PI) and its
derivatives are part of the signaling pathway in the regulation of trophoblast cell
differentiation. There are two different enzymes that take part in the direct PI synthesis:
phosphatidylinositol synthase (PIS) and inositol exchange enzyme (IE). The presence
of PIS is known in the human placenta, but IE activity has not been documented before.
In our study, we describe the physiological properties of the two enzymes in vitro.
PIS and IE were studied in different Mn2+ and Mg2+ concentrations that enabled us
to separate the individual enzyme activities. Enzyme activity was measured by incorporation
of 3[H]inositol in human primordial placenta tissue or microsomes. Optimal PIS activity
was achieved between 0.5 and 2.0 mM Mn2+ concentration, but higher concentrations
inhibit enzyme activity. In the presence of Mg2+, the enzyme activity increases continuously
up to a concentration of 100 mM. PIS was inhibited by nucleoside di- and tri-phosphates.
PI production increases between 0.1 and 10 mM Mn2+ concentration. The incorporation
of [3H]inositol into PI increased by 57% when adding stabile GTP analog. The described
novel pathway of inositol synthesis may provide an additional therapeutic approach
of inositol supplementation before and during pregnancy.
