Graphene oxide regulates cox2 in human embryonic kidney 293T cells via epigenetic mechanisms: dynamic chromosomal interactions

To extend the applications of engineered nanomaterials, such as graphene oxide (GO), it is necessary to minimize cytotoxicity. However, the mechanisms underlying this cytotoxicity are unclear. Dynamic chromosomal interactions have been used to illustrate the molecular bases of gene expression, which offers a more sensitive and cutting-edge technology to elucidate complex biological processes associated with epigenetic regulations. In this study, the role of GO-triggered chromatin interactions in the activation of cox2, a hallmark of inflammation, was investigated in normal human cells. Using chromosome conformation capture technology, we showed that GO triggers physical interactions between the downstream enhancer and the cox2 promoter in human embryonic kidney 293T (293T) via p65 and p300 complex-mediated dynamic chromatin looping, which was required for high cox2 expression. Moreover, tumor necrosis factor-α (TNF-α), located upstream of the p65 signaling pathway, contributed to the regulation of cox2 activation through dynamic chromatin architecture. Compared with pristine GO and aminated GO (GO-NH₂), poly (acrylic acid)-functionalized GO (GO-PAA) induced a weaker inflammatory response and a weaker effect on chromatin architecture. Our results mechanistically link GO-mediated chromatin interactions with the regulation of cox2 and suggest that GO derivatives may minimize toxicity in practical applications.     

Peripheral blood leukocyte telomere length is associated with age but not renal function: A cross-sectional follow-up study

Objectives

We aimed to evaluate the relationship between baseline renal function and changes in telomere length in Han Chinese.

Methods

The telomere restriction fragment (TRF) length of leukocytes in the peripheral blood was measured in healthy volunteers recruited in 2014. The estimated glomerular filtration rate (eGFR) was calculated based on serum creatinine (Scr) and serum cystatin C (CysC)-eGFRcys and eGFRScr-cys through the Cockcroft-Gault formula (eGFRC-G) or the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI / eGFRCKD-EPI) equation. The correlation between telomere length changes over time and renal function was analyzed.

Results

Leukocyte TRF lengths were negatively correlated to age (r = -0.393, p < 0.001) and serum CysC (r = -0.180, p < 0.01), while positively associated with eGFRCKD-EPI, eGFRC-G, eGFRcys, and eGFRScr-cys (r = 0.182, 0.122, 0.290, and 0.254 respectively, p < 0.01). The 3-year change of telomere length was 46 bp/years. When adjusted for age, the associations between telomere length changes and baseline, subsequent TRF lengths, and serum CysC were no longer present. No association was observed between TRF length changes and renal function.

Conclusion

The rate of telomere length changes was affected by age and baseline telomere length. The telomere length changes might be important markers for aging.

     

Histologic comparison of regeneration in human intrabony defects when osteogenin is combined with demineralized freeze-dried bone allograft and with purified bovine collagen.

A bone-inductive protein, osteogenin, has been isolated from long bones of humans and offers promise as a grafting material. Studies, however, suggest that osteogenin must be combined with a bone-derived matrix in order to initiate bone differentiation. The purpose of this study was to determine if osteogenin combined with demineralized freeze dried bone allograft (DFDBA), a bone-derived matrix, and with a bovine tendon-derived matrix will enhanced regeneration of intrabony defects in humans. The tendon-derived matrix and DFDBA used alone served as controls. The ability of each material to form a new attachment apparatus was evaluated independently in submerged and nonsubmerged environments in 2 patient populations. Lymphocyte testing was performed to assess development of an immune reaction to osteogenin. The most apical level of calculus on the root served as the histologic reference point to measure regeneration. Biopsies were obtained at 6 months and regeneration was measured histomorphometrically by 2 blinded evaluators. Serial sections from 36 submerged defects in 8 patients and 50 nonsubmerged defects in 6 patients were submitted for statistical analysis. Mean results indicate that osteogenin combined with DFDBA significantly enhanced regeneration of a new attachment apparatus and component tissues in a submerged environment. DFDBA plus osteogenin and DFDBA alone formed significantly more new attachment apparatus and component tissues than either the tendon-derived matrix plus osteogenin or the tendon-derived matrix alone in both submerged and nonsubmerged environments. There were no significant differences between the tendon-derived matrix plus osteogenin and the tendon-derived matrix alone in either the submerged or nonsubmerged environment. Osteogenin does not impair normal lymphocyte blastogenesis at 6 months postsurgical challenge.     

Anthropometric study of the upper lip and the nose of infants less than a year of age

We divided healthy newborns (aged between 2 weeks and 6 months) into four groups, less than 2 weeks old, 60 +/- 7 days, 120 +/- 7 days, and 180 +/- 7 days, between June 2001 and February 2002, and each group had 40 infants. The lineal distances included 13 items related to the nose, mouth, and lips.The average width of the columella at the midpoint was 3.2, 3.5, 3.7, and 3.8 mm for the 2-week-old group, the 2-month-old group, the 4-month-old group, and the 6-month-old group, respectively. The average height of the columella was 4.7, 4.9, 5.2, and 5.3 mm. The average length between the medial alar bases was 13.7, 14.4, 17.4, and 17.6 mm. The average length from the base to the tip of Cupid's bow was 9.5, 10.0, 10.5, and 10.6 mm. The average length from the columella lateral base to the tip of Cupid's bow was 8.4, 9.9, 10.2, and 10.5 mm. The average length from the columella central base to the center of Cupid's bow was 8.3, 9.5, 9.8, and 9.9 mm. The average width of one limb of Cupid's bow was 2.7, 3.1, 3.4, and 3.5 mm. The average length from the tip of Cupid's bow to the commissure was 13.4, 14.7, 16.4, and 16.9 mm. The average intercommissural distance was 26.8, 30.3, 30.8, and 32.7 mm. The average width of the philtral column at the columella base was 3.1, 3.6, 3.7, and 4.0 mm. The average width of the philtral columns at the mid-portion was 3.7, 4.6, 4.6, and 4.6 mm. The average height of the nasal tip protrusion was 8.7, 11.0, 11.7, and 12.1 mm. The average width of the nose was 20.7, 23.7, 25.3, and 25.9 mm. In conclusion, these data are expected to be useful for patients with a bilateral cleft lip.     

Gelatinase A (MMP-2) in developing tooth tissues and amelogenin hydrolysis

Matrix metalloproteinases (MMPs) are thought to play important roles during enamel and dentin biomineralization. Previously, membrane type-1 matrix metalloproteinase (MT1-MMP) was localized to the plasma membranes of ameloblasts and odontoblasts of the developing tooth. The best-characterized function of MT1-MMP is to initiate the activation of gelatinase A (MMP-2). Thus, we hypothesized that gelatinase A may also be expressed by developing tooth tissues. A full-length porcine gelatinase A mRNA was isolated by RT-PCR homology cloning of an enamel-organ-specific cDNA library. Northern blot and in situ hybridization analyses demonstrated gelatinase A expression in developing tooth tissues. Immunohistochemical analysis localized gelatinase A close to the plasma membrane of these tissues. Furthermore, recombinant gelatinase A was demonstrated to cleave recombinant amelogenin into several fragments of differing molecular masses. Thus, gelatinase A is expressed by developing tooth tissues along with its activator MT1-MMP and may, therefore, play an important role during tooth development.     

Effects of HB-EGF and epiregulin on wound healing of gingival cells in vitro

Oral Diseases (2011) 17 , 785–793 Objective: Gingival wound healing is important to periodontal disease and surgery. This in vitro study was conducted to assess the manner in which heparin‐binding epidermal growth factor‐like growth factor (HB‐EGF) and epiregulin cooperatively participate in the wound‐healing process in the gingival epithelial and fibroblast cells of the oral mucosa. Material and Methods: Gingival epithelium and fibroblast were separated from gingival tissue biopsies and prepared to primary cultures. The changes in the mRNA expression were evaluated via real‐time PCR. The effects on cell proliferation, migration, and repopulation were evaluated in vitro. Results: The different regulation of expressions of HB‐EGF, epiregulin, and epidermal growth factor receptors was observed over time and with different gingival cell types. HB‐EGF exerted a cell migration‐inducing effect on both epithelial and fibroblast cells, whereas epiregulin did not. Both growth factors functioned as mitogens for epithelial cell proliferation, but not for fibroblast proliferation. HB‐EGF strongly promoted epithelial cell repopulation and mildly promoted fibroblast repopulation, whereas epiregulin promoted only fibroblast repopulation. Conclusion: These results indicated that both growth factors might function importantly in the wound‐healing process of human gingival tissue via the different regulation of the expression, cell migration, proliferation, and repopulation.