• International Journal of Oral Biology
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• 제33권4호
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• pp.143-147
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• 2008

The sodium bicarbonate cotransporter (NBC) protein is functionally expressed in salivary glands. In this experiment, we examined the role of NBC in $HCO_3^-$ formation in human parotid gland acinar cells. Intracellular pH (pHi) was measured in 2'-7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF)-loaded cells. Acetazolamide (0.1 mM) and 4,4'-diisothio cyanatostilbene-2,2'-disulphonic acid (DIDS, 0.5 mM) were used as specific inhibitors of carbonic anhydrase and NBC, respectively. The degree of inhibition was assessed by measuring the pHi recovery rate (${\Delta}pHi$/min) after cell acidification using an ammonium prepulse technique. In control experiments, ${\Delta}pHi$/min was $1.40{\pm}0.06$. Treatment of cells with 0.5 mM DIDS or 0.1 mM acetazolamide significantly reduced ${\Delta}pHi$/min to $1.14{\pm}0.14$ and $0.74{\pm}0.15$, respectively. Simultaneous application of DIDS and acetazolamide further reduced ${\Delta}pHi$/min to $0.47{\pm}0.10$. Therefore, DIDS and acetazolamide reduced ${\Delta}pHi$/min by 19% and 47%, respectively, while simultaneous application of both DIDS and acetazolamide caused a reduction in ${\Delta}pHi$/min of 67%. These results suggest that in addition to carbonic anhydrase, NBC also partially contributes to $HCO_3^-$ formation in human parotid gland acinar cells.

• Journal of Korean Dental Science
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• 제4권2호
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• pp.73-78
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• 2011

Purpose: $HCO_3{^-}$ is the most important ion to buffer the acidity of saliva. The transport of $HCO_3{^-}$ is mediated by electrogenic $Na^+/HCO_3{^-}$ cotransporter 1 (NBCe1), which expressed in various tissues including salivary glands, kidney and pancreas, etc. This experiment was performed to investigate regulatory site of NBCe1involved in the pH regulation using various mutants of NBCe1. Materials and Methods: Human parotid gland NBCe1 (hpNBCe1) and mutants by deletion of 1~285 bp and 1~1,035 bp were prepared. After microinjection of each cRNA to oocytes of Xenopus laevis, they were incubated for 2~3 days. The function of each protein was tested by electrophysiological method. Results: When oocytes were exposed to the $HCO_3{^-}$ buffered solution, 1~285 bp deleted mutant hpNBCe1 evoked a marked hyperpolarization ranging from -90 mV to -160 mV (average: -134 mV; n=12) compared to the full length of hpNBCe1. Although 1~1,035 bp deleted mutant hpNBCe1 was also expressed in the plasma membrane, but it did not show any changes of membrane potentials. Conclusion: Our deletion mutant study demonstrated that 1~285 bp of the NBCe1 is the major domain to determine $HCO_3{^-}$ transport ratio.

• 한국어류학회지
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• 제32권3호
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• pp.117-129
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• 2020

생물의 종 구분에 이용하는 지표 중 체색은 특징이 뚜렷한 형태 지표로서, 어류의 종 동정에 유용한 형태형질이다. 개볼락은 한국 중부와 남부, 일본 홋카이도 남쪽 등지에 분포하는 상업적으로 중요한 어종으로, 피부에 반점의 유무 및 마킹이 있는 위치에 따라 4개의 아종으로 구분하는 복잡한 체색 특성을 갖는다. 그러나 개볼락의 다양한 체색 패턴과 관련된 유전자 탐색 및 유전자 변이 발굴 등 체색 형성에 관여하는 유전자 규명에 관한 연구는 없다. 이에 따라 본 연구에서는 개볼락의 체색 패턴 관련 유전자 발굴 및 유전자 발현 특성을 규명하기 위한 기초 연구로 체색 타입별 피부 전사체를 프로파일링하였다. 개볼락을 Wild type (반점과 marking 없음)과 Color type (반점과 마킹 모두 있음)으로 구분하였고, 피부 전사체를 RNA-seq 방법을 이용하여 분석하였다. 개볼락 피부 전사체의 발현량을 비교하여 체색 타입별 차등발현유전자 164개를 확보하였다. 이들 차등발현유전자의 기능을 Gene ontology(GO) 분석으로 확인한 결과, 2개는 molecular function, 46개는 biological process, 6개는 cellular component 기능그룹에 속하였다. 차등발현유전자 중 CTL (Galactose-specific lectin nattectin), CUL1 (Cullin-1), CMAS (N-acylneuraminate cytidylyltransferase), NMRK2 (Nicotinamide riboside kinase 2), ALOXE3 (Hydroperoxide isomerase ALOXE3), SLC4A7 (Sodium bicarbonate cotransporter 3) 등은 특정 체색 타입 특이적인 발현양상을 나타냈다. 이번 연구는 개볼락의 체색 패턴 형성에 관여하는 전사체를 탐색한 첫 번째 연구로, 체색 형성 관련 기능유전자 발굴을 위한 후보유전자로 개볼락의 체색 타입별 차등발현유전자를 확보한 것에 의의가 있다. 향후에는 이들 후보유전자의 발현양상 및 기능을 분석하여 개볼락의 복잡한 체색 패턴과 관련된 기능유전자의 특성을 밝히고자 한다.

• The Korean Journal of Physiology and Pharmacology
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• 제16권2호
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• pp.91-95
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• 2012

The role of the kidney in combating metabolic acidosis has been a subject of considerable interest for many years. The present study was aimed to determine whether there is an altered regulation of renal acid base transporters in acute and chronic acid loading. Male Sprague-Dawley rats were used. Metabolic acidosis was induced by administration of $NH_4Cl$ for 2 days (acute) and for 7days (chronic). The serum and urinary pH and bicarbonate were measured. The protein expression of renal acid base transporters [type 3 $Na^+/H^+$ exchanger (NHE3), type 1 $Na^+/{HCO_3}^-$ cotransporter (NBC1), Na-$K^+$ ATPase, $H^+$-ATPase, anion exchanger-1 (AE-1)] was measured by semiquantitative immunoblotting. Serum bicarbonate and pH were decreased in acute acid loading rats compared with controls. Accordingly, urinary pH decreased. The protein expression of NHE3, $H^+$-ATPase, AE-1 and NBC1 was not changed. In chronic acid loading rats, serum bicarbonate and pH were not changed, while urinary pH was decreased compared with controls. The protein expression of NHE3, $H^+$-ATPase was increased in the renal cortex of chronic acid loading rats. These results suggest that unaltered expression of acid transporters combined with acute acid loading may contribute to the development of acidosis. The subsequent increased expression of NHE3, $H^+$-ATPase in the kidney may play a role in promoting acid excretion in the later stage of acid loading, which counteract the development of metabolic acidosis.

• International Journal of Stem Cells
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• 제15권4호
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• pp.384-394
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• 2022

Background and Objectives: Dental pulp stem cells (DPSCs) play an important role in the repair of tooth injuries. Electrogenic sodium bicarbonate cotransporter 1 (NBCe1) is a Na⁺-coupled HCO₃^- transporter encoded by the solute carrier 4A4 (SLC4A4) gene and plays a crucial role in maintaining the pH of DPSCs. Our previous research confirmed that NBCe1 is highly expressed in odontoblasts during the development of the tooth germ. Therefore, in this study, we aimed to investigate the effect of NBCe1 on odontogenic differentiation of DPSCs and further clarify the underlying mechanisms. Methods and Results: DPSCs were isolated and identified, and the selective NBCe1 inhibitor S0859 was used to treat DPSCs. We used a cell counting Kit-8 assay to detect cell proliferative ability, and intracellular pH was assessed using confocal microscopy. Odontogenic differentiation of DPSCs was analyzed using real-time PCR and Alizarin Red S staining, and the NF-κB pathway was assessed using western blotting. Our results indicated that 10 µM S0859 was the optimal concentration for DPSC induction. Intracellular pH was decreased upon treatment with S0859. The mRNA expressions of DSPP, DMP1, RUNX2, OCN, and OPN were upregulated in the NBCe1 inhibited group compared to the controls. Moreover, NBCe1 inhibition significantly activated the NF-κB pathway, and a NF-κB inhibitor reduced the effect of NBCe1 on DPSC differentiation. Conclusions: NBCe1 inhibition significantly promotes odontogenic differentiation of DPSCs, and this process may be regulated by activating the NF-κB signaling pathway.