Serum or growth factor deprivation induces the expression of alkaline phosphatase in human gingival fibroblasts

A human vitamin D receptor mutation causes rickets and impaired Th1/Th17 responses

We present a brother and sister with severe rickets, alopecia and highly elevated serum levels of 1,25-dihydroxyvitamin D (1,25-(OH)2D3). Genomic sequencing showed a homozygous point mutation (A133G) in the vitamin D receptor gene, leading to an amino acid change in the DNA binding domain (K45E), which was described previously. Hereditary vitamin D resistant rickets (HVDRR) was diagnosed. Functional studies in skin biopsy fibroblasts confirmed this. 1,25-(OH)2D3 reduced T helper (Th) cell population-specific cytokine expression of interferon γ (Th1), interleukins IL-17A (Th17) and IL-22 (Th17/Th22) in peripheral blood mononuclear cells (PBMCs) from the patient's parents, whereas IL-4 (Th2) levels were higher, reflecting an immunosuppressive condition. None of these factors were regulated by 1,25-(OH)2D3 in PBMCs from the boy. At present, both patients (boy is 23 years of age, girl is 7) have not experienced any major immune-related disorders. Although both children developed alopecia, the girl did so earlier than the boy. The boy showed complete recovery from the rickets at the age of 17 and does not require any vitamin D supplementations to date. In conclusion, we characterized two siblings with HVDRR, due to a mutation in the DNA binding domain of VDR. Despite a defective T cell response to vitamin D, no signs of any inflammatory-related abnormalities were seen, thus questioning an essential role of vitamin D in the immune system. Despite the fact that currently medicine is not required, close monitoring in the future of these patients is warranted for potential recurrence of vitamin D dependence and diagnosis of (chronic) inflammatory-related diseases.

Low-intensity laser irradiation stimulates wound healing in diabetic wounded fibroblast cells (WS1)

BACKGROUND

Patients with diabetes suffer from slow-to-heal wounds, which often necessitate amputation. Low-intensity laser irradiation (LILI) has been shown to reduce the healing time in such patients. This study aimed to determine the effect of different wavelengths of LILI on cellular migration, viability, and proliferation in a wounded diabetic cell model.

METHODS

Diabetic wounded and unwounded human skin fibroblast cells (WS1) were irradiated at 632.8, 830, or 1,064 nm with 5 J/cm(2). Cellular morphology and migration were determined microscopically, while cellular viability was determined by ATP luminescence, and proliferation was determined by basic fibroblast growth factor expression and alkaline phosphatase activity.

RESULTS

Diabetic wounded cells irradiated at 1,064 nm showed a lesser degree of migration, viability, and proliferation compared to cells irradiated at 632.8 or 830 nm. Cells irradiated at 632.8 nm showed a higher degree of haptotaxis and migration as well as ATP luminescence compared to cells irradiated at 830 nm.

CONCLUSIONS

This study showed that LILI of diabetic wounded cells in the visible range (632.8 nm) was more beneficial to wound healing than irradiating the same cells to wavelengths in the infrared range. Cells irradiated at a longer wavelength of 1,064 nm performed worse.

cAMP-dependent protein kinase regulates post-translational processing and expression of complex I subunits in mammalian cells

Work is presented on the role of cAMP-dependent protein phosphorylation in post-translational processing and biosynthesis of complex I subunits in mammalian cell cultures. PKA-mediated phosphorylation of the NDUFS4 subunit of complex I promotes in cell cultures in vivo import/maturation in mitochondria of the precursor of this protein. The import promotion appears to be associated with the observed cAMP-dependent stimulation of the catalytic activity of complex I. These effects of PKA are counteracted by activation of protein phosphatase(s). PKA and the transcription factor CREB play a critical role in the biosynthesis of complex I subunits. CREB phosphorylation, by PKA and/or CaMKs, activates at nuclear and mitochondrial level a transcriptional regulatory cascade which promotes the concerted expression of nuclear and mitochondrial encoded subunits of complex I and other respiratory chain proteins.

Irradiation with a 632.8 nm helium-neon laser with 5 J/cm2 stimulates proliferation and expression of interleukin-6 in diabetic wounded fibroblast cells

BACKGROUND

The use of lasers has been shown to stimulate wound healing in vivo and in vitro. There is an increase in wound closure, cell viability, proliferation, and cytokine expression. If laser parameters can be optimized and standardized, and the underlying mechanisms better understood, this phototherapy can become an alternative safe treatment to slow-to-heal wounds, such as in patients with diabetes. This study aimed to determine the effect on cellular proliferation, migration, and cytokine [interleukin-6 (IL-6)] expression in diabetic and diabetic wounded fibroblast cells (WS1) post-laser irradiation.

METHODS

Diabetic and diabetic wounded WS1 cells were irradiated at 632.8 nm (23 mW) with 5 J/cm(2) or 16 J/cm(2). IL-6 level, cellular proliferation (neutral red assay), and morphology were then determined.

RESULTS

Diabetic cells irradiated with 5 J/cm(2) showed no significant change, while diabetic wounded cells showed an increase in IL-6 level, proliferation, and migration. On the other hand, diabetic and diabetic wounded cells irradiated with 16 J/cm(2) showed a significant decrease in proliferation and evidence of cellular damage, and wounded cells showed no migration.

CONCLUSION

This study showed that phototherapy at the correct fluence stimulates IL-6 expression, proliferation, and cellular migration in diabetic wounded cells. A fluence of 5 J/cm(2) stimulates diabetic wound healing in vitro, while 16 J/cm(2) is inhibitive.

Influence of Broad-Spectrum and Infrared Light in Combination with Laser Irradiation on the Proliferation of Wounded Skin Fibroblasts

OBJECTIVE

This study aimed to establish if broad-spectrum or infrared (IR) light in combination with laser therapy can assist phototherapy and accelerate cell proliferation to improve the rate of wound healing.

BACKGROUND DATA

The effect of laser light may be partly or completely reduced by broad-spectrum light. There are few studies that investigate the benefit or detriment of combining laser irradiation with broad-spectrum or IR light.

METHODS

Wounded human skin fibroblasts were irradiated with a dose of 5 J/cm(2) using a heliumneon laser, a diode laser, or a Nd:YAG laser in the dark, in the light, or in IR. Changes in cell proliferation were evaluated using optical density at 540 nm, alkaline phosphatase (ALP) enzyme activity, cytokine expression, and basic fibroblast growth factor (bFGF) expression.

RESULTS

The optical density and ALP enzyme activity indicate that 5 J/cm(2) using 1064 nm in the light is more effective in increasing cell proliferation or cell growth than 830 nm in the light, but not as effective as 632.8 nm in the light. bFGF expression shows that the response of wounded cells exposed to 5 J/cm(2) in IR light is far less than the biological response of wounded cells exposed to 5 J/cm(2) in the dark or light. The results indicate that wounded cells exposed to 5 J/cm(2) using 632.8 nm in the dark results in a greater increase in IL-6 when compared to cells exposed to 5 J/cm(2) in the light or in IR.

CONCLUSION

Results indicate that 5 J/cm(2) (using 632.8 nm in the dark or 830 nm in the light) is the most effective dose to stimulate cell proliferation, which may ultimately accelerate or improve the rate of wound healing.

Effect of multiple exposures of low-level laser therapy on the cellular responses of wounded human skin fibroblasts

OBJECTIVE

This study aimed to establish the behavior of wounded human skin fibroblasts (HSF) after heliumneon (HeNe) (632.8 nm) laser irradiation using one, two, or three exposures of different doses, namely, 2.5, 5.0, or 16.0 J/cm(2) on each day for 2 consecutive days.

BACKGROUND DATA

Low-level laser therapy (LLLT) is a form of phototherapy used to promote wound healing in different clinical conditions. LLLT at than adequate wavelength, intensity, and dose can accelerate tissue repair. However, there is still conflicting information about the effect of multiple irradiations on the cellular responses of wounded cells.

METHODS

Cellular responses to HeNe laser irradiation were evaluated by measuring changes in cell morphology, cell viability, cell proliferation, and damage caused by multiple irradiations.

RESULTS

A single dose of 5.0 J/cm(2), and two or three doses of 2.5 J/cm(2) had a stimulatory or positive effect on wounded fibroblasts with an increase in cell migration and cell proliferation while maintaining cell viability, but without causing additional stress or damage to the cells. Multiple exposures at higher doses (16 J/cm(2)) caused additional stress, which reduces cell migration, cell viability, and ATP activity, and inhibits cell proliferation.

CONCLUSION

The results show that the correct energy density or fluence (J/cm(2)) and number of exposures can stimulate cellular responses of wounded fibroblasts and promote cell migration and cell proliferation by stimulating mitochondrial activity and maintaining viability without causing additional stress or damage to the wounded cells. Results indicate that the cumulative effect of lower doses (2.5 or 5 J/cm(2)) determines the stimulatory effect, while multiple exposures at higher doses (16 J/cm(2)) result in an inhibitory effect with more damage.

IGF-I mediated survival pathways in normal and malignant cells

The type-I and -II insulin-like growth factors (IGF-I, II) are now established as survival- or proliferation-factors in many in vitro systems. Of note IGFs provide trophic support for multiple cell types or organ cultures explanted from various species, and delay the onset of programmed cell death (apoptosis) through the mitochondrial (intrinsic pathway) or by antagonizing activation of cytotoxic cytokine signaling (extrinsic pathway). In some instances, IGFs protect against other forms of death such as necrosis or autophagy. The effect of IGFs on cell survival appears to be context specific, being determined both by the cell origin (tissue specific) and the cellular stress that induces loss of cellular viability. In many human cancers, there is a strong association with dysregulated IGF signaling, and this association has been extensively reviewed recently. IGF-regulation is also disrupted in childhood cancers as a consequence of chromosomal translocations. IGFs are implicated also in acute renal failure, traumatic injury to brain tissue, and cardiac disease. This article focuses on the role of IGFs and their cellular signaling pathways that provide survival signals in stressed cells.

Extracellular matrix regulates induction of alkaline phosphatase expression by ascorbic acid in human fibroblasts

During wound healing and inflammation, fibroblasts express elevated alkaline phosphatase (ALP), but are not in contact with collagen fibrils in the fibronectin (FN)-rich granulation tissue. We hypothesized that the extracellular matrix (ECM) environment might influence the induction of ALP in fibroblasts. Here we tested this hypothesis by studying the ALP-inductive response of normal human gingival fibroblasts to ascorbic acid (AsA). AsA induced ALP activity and protein in cells in conventional monolayer culture. This induction was inhibited by blocking-antibodies to the FN receptor alpha 5 beta 1 integrin and by the proline analog 3,4-dehydroproline (DHP). DHP prevented cells from arranging FN fibrils into a pericellular network and reduced the activity of cell spreading on FN. Plating of cells on FN facilitated the up-regulation by AsA of ALP expression, but did not substitute for AsA. In contrast, AsA did not cause ALP induction in cells cultured on and in polymerized type I collagen gels. Collagen fibrils inhibited the up-regulation by AsA of ALP expression in cells plated on FN. These results indicate that the ECM regulates the induction of ALP expression by AsA in fibroblasts: FN enables them to express ALP in response to AsA through interaction with integrin alpha 5 beta 1, whereas type I collagen fibrils cause the suppression of ALP expression and overcome FN.

Cytotoxicity of root canal filling materials to three different human cell lines

The aim of this study was to investigate the biological compatibility of five root canal sealers (Sealapex, Endion, Super-EBA, Ketac-Endo, and AH Plus) and regular and calcium hydroxide-based gutta-percha in three different human cell lines. Cultures without root canal sealers were used as controls. Cell growth, cell morphology, cell viability, protein content of the cells, and prostaglandin E2 (PGE2) release were used as parameters to determine the cytotoxicity of the materials. The protein content of the three cell lines--nasal fibroblasts, gingival fibroblasts, and epithelial tumor cells--was significantly reduced (p < or = 0.001) by all materials tested. Determinations of PGE2 release showed significant material specific differences. No significant increased PGE2 release values were found with Sealapex, Endion, and Super-EBA. On the contrary significantly increased PGE2 levels were measured with Ketac Endo, AH Plus, regular and calcium hydroxide-based gutta-percha points (p < or = 0.001).