Action of Boron at the Molecular Level Effects on Transcription and Translation in an Acellular System

Abstract

It has been shown that boric acid has well-defined biological effects such as stimulation of wound healing in vivo, release of growth factors and cytokines, and increase of the extracellular matrice turnover. We examined its action at the molecular level, using cell-free systems of transcription (isolated placenta nuclei) and translation (wheat germ extract). We found that 10 mM boric acid greatly increased RNA synthesis, measured by absorbance at 260 nm (x 6.4) or by [3H]-UTP uptake (x 11). Full-length functional mRNA was produced because proteins of 14-80 kDa were translated. Among these proteins, factors involved in angiogenesis and, subsequently, in wound healing (VEGF and TGFbeta) were identified by slot blot, whereas growth factors such as FGF1 and TNFalpha were not detected. These results demonstrate that boron may contribute to biological cell activities at both the transcription and translation levels. However, the mechanism of action is still not known.

A critical analysis of the causes of boron toxicity in plants

“…There appears to be little information in the literature on the functional interaction between B and RNA except for a report by Al‐Yousif, Al‐Whaibi & El‐Hirweris (1994) who noted that RNA content of date palm and sorghum increased when seedlings growing in vermiculite were watered with nutrient solution containing 1 m m B. Similar increases in RNA were found in cell free assays of animal tissues exposed to 10 m m B (Dzondo‐Gadet et al . 2002).…”

Boron regulates mineralized tissue-associated proteins in osteoblasts (MC3T3-E1)

“…They identified the factors involved in angiogenesis and, subsequently, in wound healing (VEGF and TGF-beta) by slot blot, but not FGF1 and TNF-alpha. Their results displayed that B may contribute to biological cell activities at both the transcription and translation levels [28]. In our study, we did not check the growth factors but we did examine differentiation factors including BMP-4, -6 and -7.…”

Asexual Reproduction and Segmental Regeneration, but not Morphallaxis, are Inhibited by Boric Acid in Lumbriculus variegatus (Annelida: Clitellata: Lumbriculidae)

“…These results indicate that at least one regenerative process, neural morphallaxis, has been incorporated in asexual reproduction and although the mechanism of action of boric acid in these studies is unknown, it has been implicated in developmental defects in other systems including vertebrate axial development (Price et al, 1996;Fort et al, 1998). Boric acid is not metabolized in humans or animals (Murray, 1995) and at low consumption is reported to aid in wound healing possibly by increasing RNA synthesis of tumor necrosis factors (Benderdour et al, 1998), vascular endothelial growth factors and transforming growth factors (Dzondo-Gadet et al, 2002). Whether or not environmental levels of boric acid ever attain concentrations capable of impacting annelid asexual reproduction remains to be studied.…”