Mutation of dentin sialophosphoprotein and hereditary malformations of dentin / 中华口腔医学杂志

The classification as well as the clinical manifestations of hereditary malformations of dentin are of great concern and have been deeply elucidated. The understanding of its genetic basis also increases progressively. Dentin sialophosphoprotein (DSPP) is the pathogenic gene of dentinogenesis imperfecta type Ⅱ, dentinogenesis imperfecta type Ⅲ and dentin dysplasia type Ⅱ. In this article, the classification of DSPP mutations as well as the resultant dysfunction of the mutant DSPP are summarized respectively and the corresponding clinical manifestations are analyzed. This work will provide a reference for the diagnosis and treatment of hereditary malformations of dentin.

Polymorphisms in DSSP (rs36094464) and RUNX2 (rs566712) genes contribute to the susceptibility of dental caries in childhood / Los polimorfismos en los genes DSSP (rs36094464) y RUNX2 (rs566712) contribuyen a la susceptibilidad de la caries dental en la infancia

SUMMARY: Dental caries corresponds to an ecological and non-contagious, dynamic and chronic disease of multifactorial origin; currently there is evidence of how genetic factors could be included as predisposing agents to suffer it, however this evidence is diverse and incipient. a cross-sectional study was p erformed to investigate the possible associations of DSPP (rs36094464), RUNX2 (rs566712) and KLK4 (rs198968) polymorphisms in early childhood caries. Saliva samples of children (2-11years old) were collected and genotyped for DSPP (rs36094464), RUNX2 (rs566712) and KLK4 (rs198968) polymorphisms. Through the ceft index their caries history was determined and the gene variants were students through molecular biology techniques. polymorphisms of the DSSP (rs36094464) and RUNX2 (rs566712) are associated and contribute to the susceptibility of dental caries disease in early childhood, as they are related to their history of caries. KLK4 (rs198968) polymorphisms are not associated. In conclusions, the studied polymorphisms on DSSP and RUNX2 genes are associated with changes in the tooth microarchitecture, favoring the appearance of microlesions that would contribute to dental caries disease susceptibility in early childhood. Also, no association was found for the studied polymorphism of the KLK4 gene with dental caries disease susceptibility.

RESUMEN: La caries dental corresponde a una enfermedad crónica, no contagiosa, dinámica y de origen multifactorial. Actualmente existe evidencia de cómo los factores genéticos podrían incluirse como agentes predisponentes, sin embargo, esta evidencia es diversa e incipiente. Se realizó un estudio transversal para investigar las posibles asociaciones entre los polimorfismos DSPP (rs36094464), RUNX2 (rs566712) y KLK4 (rs198968) y la caries en la infancia. Se colectaron muestras de saliva de niños (de 2 a 11 años de edad) y se genotipificaron para los polimorfismos DSPP (rs36094464), RUNX2 (rs566712) y KLK4 (rs198968). Mediante el índice ceft se determinó su historial de caries y se estudiaron las variantes genéticas mediante técnicas de biología molecular. Los datos obtenidos indican que los polimorfismos del DSSP (rs36094464) y RUNX2 (rs566712) están asociados y contribuyen a la susceptibilidad de la enfermedad de caries dental en la infancia, ya que están - además - relacionados con el historial de caries. En conclusión, los polimorfismos estudiados en los genes DSSP y RUNX2 se asocian a la aparición de microlesiones que contribuirían a la susceptibilidad a la enfermedad de caries dental en la infancia. Creemos que este estudio es importante para la odontopediatría porque destaca el papel de DSSP (rs36094464) y RUNX2 (rs566712) y la susceptibilidad a la caries dental durante la infancia, además resalta la utilidad de la evaluación genética para la predicción y prevención de la caries dental y porque aporta evidencia que indica que los factores genéticos están implicados en la etiología de la caries.

Isolation and characterization of a human cementocyte-like cell line, HCY-23

Abstract Cementum is the mineralized tissue covering the tooth root that functions in tooth attachment and post-eruptive adjustment of tooth position. It has been reported to be highly similar to bone in several respects but remains poorly understood in terms of development and regeneration. Here, we investigate whether cementocytes, the residing cells in cellular cementum, have the potential to be protagonist in cementum homeostasis, responding to endocrine signals and directing local cementum metabolism. Cells from healthy erupted human teeth were isolated using sequential collagenase/EDTA digestions, and maintained in standard cell culture conditions. A cementocyte-like cell line was cloned (HCY-23, for human cementocyte clone 23), which presented a cementocyte compatible gene expression signature, including the expression of dentin matrix protein 1 ( DMP1 ), sclerostin ( SOST ), and E11/gp38/podoplanin ( E11 ). In contrast, these cells did not express the odontoblast/dentin marker dentin sialoprotein ( DSPP ). HCY-23 cells produced mineral-like nodules in vitro under differentiation conditions, and were highly responsive to inorganic phosphate (Pi). Within the limits of the present study, it can be concluded that cementocytes are phosphate-responsive cells, and have the potential do play a key role in periodontal homeostasis and regeneration.

Hydrochloride pioglitazone protects diabetic rats against podocyte injury through preserving glomerular podocalyxin expression / O cloridrato de pioglitazona protege ratos diabéticos contra a injúria aos podócitos por meio da preservação da expressão de podocalixina glomerular

Objective: We sought to test the effect of different dosages of pioglitazone (PIO) on the glomerular expression of podocalyxin and urinary sediment podocalyxin excretion and to explore the potential renoprotective mechanism. Materials and methods: Type 1 diabetes induced with streptozotocin (65 mg/kg) in 36 male Sprague-Dawley rats were randomly allocated to be treated with vehicle or 10, 20, 30 mg/kg/d PIO respectively for 8 weeks. Eight rats were enrolled in the normal control group. Results: At 8th week, rats were sacrificed for the observation of kidney injury through electron microscope. Glomerular podocalyxin production including mRNA and protein were determined by RT-PCR and immunohistochemistry respectively. Levels of urinary albumin excretion and urinary sediment podocalyxin, kidney injury index were all significantly increased, whereas expression of glomerular podocalyxin protein and mRNA were decreased significantly in diabetic rats compared to normal control. Dosages-dependent analysis revealed that protective effect of PIO ameliorated the physiopathological changes and reached a peak at dosage of 20 mg/kg/d. Conclusion: PIO could alleviate diabetic kidney injury in a dose-dependent pattern and the role may be associated with restraining urinary sediment podocalyxin excretion and preserving the glomerular podocalyxin expression. .

Objetivo: Buscamos testar os efeitos de diferentes doses de pioglitazona (PIO) sobre a expressão glomerular de podocalixina e sobre a excreção de podocalixina em células do sedimento urinário, além de explorar o potencial mecanismo de proteção renal. Materiais e métodos: O diabetes tipo 1 foi induzido em 36 ratos Sprague-Dawley machos com estreptozotocina (65 mg/kg). Os animais foram tratados apenas com o veículo, ou com 10, 20, 30 mg/kg/d de PIO por 8 semanas. Oito ratos foram colocados no grupo controle. Resultados: Na oitava semana, os ratos foram sacrificados para se observar a lesão renal em microscopia eletrônica. A produção de podocalixina glomerular, incluindo mRNA e proteína, foi determinada por RT-PCR e imuno-histoquímica, respectivamente. Os níveis urinários de albumina e podocalixina nas células do sedimento urinário e o índice de lesão renal estavam todos significativamente aumentados, enquanto a expressão glomerular da proteína podocalixina e do mRNA estava significativamente diminuída em ratos diabéticos comparados com o controle normal. A análise dos efeitos dose-dependentes revelou que o efeito protetor da PIO melhorou as mudanças fisiopatológicas e atingiu um pico na dose de 20 mg/kg/dia. Conclusão: A PIO pode melhorar a injúria renal de forma dose-dependente e este papel pode estar associado com a prevenção da excreção de podocalixina nas células do sedimento urinário e com a preservação da expressão glomerular de podocalixina. .

Influence of the microenvironment on gene and protein expression of odontogenic-like and osteogenic-like cells

Progenitor cells play an important biological role in tooth and bone formation, and previous analyses during bone and dentine induction have indicated that they may be a good alternative for tissue engineering. Thus, to clarify the influence of the microenvironment on protein and gene expression, MDPC-23 cells (mouse dental papilla cell line) and KUSA/A1 cells (bone marrow stromal cell line) were used, both in vitro cell culture and in intra-abdominal diffusion chambers implanted in 4-week-old male immunodefficient mice (SCID mice). Our results indicate that KUSA/A1 cells differentiated into osteoblast-like cells and induced bone tissue inside the chamber, whereas, MDPC-23 showed odontoblast-like characteristics but with a low ability to induce dentin formation. This study shows that MDPC-23 cells are especial cel ls, which possess morphological and functional characteristics of odontoblast-like cells expressing dentin sialophosphoprotein in vivo. In contrast, dentin sialophosphoprotein gene and protein expression was not detected in both cell lines in vitro. The intra-abdominal diffusion chamber appears as an interesting experimental model for studying phenotypic expression of dental pulp cells in vivo.

Ethnicity greatly influences the interleukin-1 gene cluster(IL-1b promoter, exon-5 and IL-1Ra) polymorphisms: a pilot study of a north Indian population.

There is considerable evidence that polymorphisms in the regulatory regions of cytokine genes are highly influenced by ethnicity. Polymorphisms in interleukin 1-beta (IL-1beta) and IL-1 receptor antagonist (IL-1Ra) genes, respectively encoding a potent inflammatory agent and an antagonist, which combines with IL-1 receptors competitively, have been associated with a number of diseases like systemic lupus erythematosus, rheumatoid arthritis, sepsis, kidney diseases, and cancer. In this study, we therefore evaluated the distribution of interleukin-1 gene cluster (IL-1beta promoter region, exon-5 and IL-1Ra) gene polymorphisms in 206 healthy north Indian subjects, using PCR-based restriction analysis. We also constructed various haplotypes and estimated the linkage disequilibrium (LD). We found that genotype and allelic frequencies for these cytokines were conspicuously different when compared among different ethnic populations. The haplotype 'T-E1-1' predominated (41.7%) while the least common was 'C-E2-2' (2%) in our population. Genetic linkage between three loci of IL-1 gene showed strong association among the variants in controls (D'=0.42, p<0.001). Our results suggest that the frequency and distribution of the polymorphisms in India are substantially different from other populations and ethnic groups. Thus they signify an impact of ethnicity and provide a basis for future epidemiological and clinical studies.

Influence of non-MHC genes on lymphocyte response to Mycobacterium tuberculosis antigens & tuberculin reactive status in pulmonary tuberculosis.

BACKGROUND & OBJECTIVES: Major histocompatibility complex (MHC) genes are known to influence the immune functions. In the present study, the influence of non-MHC genes such as mannose binding protein (MBP), vitamin D receptor (VDR) and interleukin-1 receptor antagonist (IL-1RA) gene polymorphisms on lymphocyte response to Mycobacterium tuberculosis culture filtrate antigen (10 micrograms/ml) was studied in 44 patients with active pulmonary TB and the family contacts (35) and in 32 normal healthy subjects. The influence of these gene polymorphisms on tuberculin (1TU of PPD of M. tuberculosis) reactivity status in 146 pulmonary TB patients was also studied. METHODS: The MBP and VDR genes were amplified using polymerase chain reaction (PCR) and genotyping was carried out using sequence specific oligonucleotide probes by dot blot and IL-1RA by agarose gel electrophoresis. RESULTS: A significantly decreased lymphocyte response to M. tuberculosis antigen was seen in pulmonary TB patients positive for functional mutant homozygotes of MBP (OO) compared to heterozygote carriers (AO; P < 0.02) and wild homozygotes (AA; P < 0.01). The variant mutant genotype (tt) of VDR gene was associated with an increased lymphocyte response in control subjects compared to active TB patients with tt genotype (P < 0.05). Heterozygote carriers of MBP (AO) were associated with a significantly (P < 0.001) decreased tuberculin reactivity compared to wild homozygotes (AA). The VDR genotype Tt (heterozygote carrier) was associated with an increased tuberculin reactivity in female TB patients as compared to male patients (P < 0.001). INTERPRETATION & CONCLUSIONS: The present study suggested that MBP and VDR genes influence the cell mediated immune response in pulmonary TB patients. Non-MHC genes along with HLA-Class II genes/gene products may be playing an immunoregulatory role in the mechanism of susceptibility/resistance to tuberculosis.

Individual or combined effects of enalapril and verapamil on chronic cyclosporine nephrotoxicity in rats

Previous studies have demonstrated that enalapril and verapamil seem to attenuate the cyclosporine nephrotoxicity. However, the mechanisms have not been completely understood, especially on molecular events. The aim of this study was to examine the effect of individual or combined treatment on osteopontin, TGF-beta, endothelin-1 and procollagen alpha 1(I) mRNA expressions. Enalapril (50 mg/L in drinking water) and verapamil (0.5 mg/kg/day, subcutaneously), alone or in combination, were administered to rats with chronic cyclosporine nephrotoxicity (cyclosporine, 25 mg/kg/day, subcutaneously) (n = 5 each). Five rats treated with olive oil vehicle were used as control. After 4 weeks, biochemical parameters were measured, and renal cortical mRNA levels were evaluated by Northern blot analysis. Cyclosporine reduced renal creatinine clearance significantly and induced renal cortical osteopontin, TGF-beta, endothelin-1 and procollagen alpha 1(I) gene expressions around 13.5 +/- 1.3, 2.4 +/- 0.2, 1.5 +/- 0.1, 1.9 +/- 0.1 folds, respectively. Individual treatment with enalapril or verapamil significantly suppressed the osteopontin and TGF-beta mRNA expression, but not endothelin-1 and procollagen alpha 1(I). Combined treatment also inhibited the osteopontin and TGF-beta mRNA expression but there was no difference between combined and individual treatment. In conclusion, enalapril or verapamil significantly blunted the cyclosporine-induced osteopontin and TGF-beta gene expressions. However, combined treatment did not show any additive effect.