Effects of sodium fluoride (NaF) on the cilia and microtubular system of Tetrahymena

Abstract

The effect of the nucleophilic reagent NaF on the microtubular system of Tetrahymena was studied by using scanning electron microscopy (SEM), confocal microscopy, and flow cytometry. Treatments with 40 mM NaF significantly reduced the amount of alpha-tubulin while 80 mM treatment did not alter its quantity. One possible explanation for this alpha-tubulin overexpression is that the higher amount of alpha-tubulin enables this organism to carry out the appropriate function of the cytoskeleton under this undesirable influence of higher amounts of 80 nM NaF. However, the amount of acetylated tubulin increased in a dose-dependent manner. The cilia became fragile under the effect of 80 mM NaF. Confocal microscopy revealed that after 40 mM NaF treatment transversal microtubule bands (TMs) and longitudinal microtubule bands (LMs) as well as basal bodies (BBs) were extremely strong decorated with anti-acetylated tubulin antibody and TM-localization abnormalities were visible. In the 80 mM NaF-treated cells, the deep fiber of oral apparatus was very strongly labeled, while the TMs and LMs were less decorated with anti-acetylated tubulin antibody, and LM deformities were visible. It is supposed that post-translational tubulin modifications (e.g., acetylation) defend the microtubules against the NaF-induced injury. NaF is able to influence the activity of several enzymes and G-proteins, therefore is capable to alter the structure, metabolism, and the dynamics of microtubular system. The possible connection of signaling and cytoskeletal system in Tetrahymena is discussed.

Fluoride inhibits the response of bone cells to mechanical loading

“…These findings agree with a study showing that fluoride affects the activity of several g-proteins involved in the microtubular system and other cytoskeletal compounds in protozoa [21]. Since the response of bone cells to mechanical loading is mediated by the cytoskeleton [11], our findings suggest that fluoride affects the mechano-response of osteoblasts via modulation of cellular F-actin.…”

“…Fluoride is present in varying amounts in air, water, and food, and is an essential trace element in the skeletal system and teeth [20]. Fluoride disrupts the cytoskeleton of protozoa [21] and F-actin in ameloblasts [22]. Since fluoride affects bone mass and cytoskeleton, we hypothesized that fluoride inhibits the response of mechano-sensitive bone cells to mechanical loading.…”

Effects of Fluoride on Submandibular Glands of Mice: Changes in Oxidative Biochemistry, Proteomic Profile, and Genotoxicity

“…Alpha- and beta-tubulin dimers form the microtubules related to specific proteins and regulate certain signaling pathways mediated by the G protein. Previous studies indicate that F alters the structure, metabolism, and dynamics of the microtubular system ( Wang et al, 1990 ; Kovács et al, 2008 ; Monteiro et al, 2011 ). In this study, the beta-tubulin protein-3 (Q9ERD7), beta-4 (Q9D6F9), beta-4B (P68372), beta-2B (Q9CWF2), beta-5 (P99024) beta-2A (Q7TMM9), beta-6 (Q922F4), alpha-1a (P68369), and alpha-4a (P68368) were downregulated after exposure to the 50 mgF/L group ( Supplementary Table S4 ).…”

“…The cellular cytoskeleton is mainly composed of microfilaments, intermediate filaments, and microtubules. Alpha-and beta-tubulin dimers form the microtubules related (Wang et al, 1990;Kovács et al, 2008;Monteiro et al, 2011). In this study, the beta-tubulin protein-3 (Q9ERD7), beta-4 (Q9D6F9), beta-4B (P68372), beta-2B (Q9CWF2), beta-5 (P99024) beta-2A (Q7TMM9), beta-6 (Q922F4), alpha-1a (P68369), and alpha-4a (P68368) were downregulated after exposure to the 50 mgF/L group (Supplementary Table S4).…”

Diet and Exercise: a Match Made in Bone

“…When thinking of cytoskeleton-affecting dietary components, a few come to mind. First, fluoride is known to disrupt the actin cytoskeleton of protozoa [ 50 ] and actin fibers in ameloblasts [ 51 ], leading to a disrupted actin cytoskeleton and more rounded cells [ 51 ]. Fluoride might thus enhance osteocyte mechanosensitivity by altering osteocyte shape, although the intake would have to be relatively high, considering the dose required to affect the actin cytoskeleton.…”