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TRPV1 in Salivary Gland Epithelial Cells Is Not Involved in Salivary Secretion via Transcellular Pathway.

Choi S, Shin YH, Namkoong E, Hwang SM, Cong X, Yu G, Park K - Korean J. Physiol. Pharmacol. (2014)

Bottom Line: However, capsaicin (CAP), TRPV1 agonist, had little effect on intracellular free calcium concentration ([Ca(2+)]i) in these cells, although carbachol consistently increased [Ca(2+)]i.Saliva flow rate also showed insignificant change in the mice treated with PILO plus CAP compared with that in mice treated with PILO alone.Taken together, our results suggest that although TRPV1 is expressed in SGEC, it appears not to play any direct roles in saliva secretion via transcellular pathway.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, School of Dentistry, Seoul National University and Dental Research Institute, Seoul 110-749, Korea.

ABSTRACT
Transient receptor potential vanilloid subtype 1 (TRPV1) was originally found in sensory neurons. Recently, it has been reported that TRPV1 is expressed in salivary gland epithelial cells (SGEC). However, the physiological role of TRPV1 in salivary secretion remains to be elucidated. We found that TRPV1 is expressed in mouse and human submandibular glands (SMG) and HSG cells, originated from human submandibular gland ducts at both mRNA and protein levels. However, capsaicin (CAP), TRPV1 agonist, had little effect on intracellular free calcium concentration ([Ca(2+)]i) in these cells, although carbachol consistently increased [Ca(2+)]i. Exposure of cells to high temperature (>43℃) or acidic bath solution (pH5.4) did not increase [Ca(2+)]i, either. We further examined the role of TRPV1 in salivary secretion using TRPV1 knock-out mice. There was no significant difference in the pilocarpine (PILO)-induced salivary flow rate between wild-type and TRPV1 knock-out mice. Saliva flow rate also showed insignificant change in the mice treated with PILO plus CAP compared with that in mice treated with PILO alone. Taken together, our results suggest that although TRPV1 is expressed in SGEC, it appears not to play any direct roles in saliva secretion via transcellular pathway.

No MeSH data available.


Related in: MedlinePlus

Expression of TRPV1 in salivary gland epithelial cells (SGEC). (A) Expression of TRPV1 mRNA in mouse SMG (mSMG), human SMG (hSMG), and HSG cells by RT-PCR, with GAPDH as an internal control. (B) Expression of TRPV1 protein in mSMG, hSMG, and HSG cells by Western blot. Approximately 50 µg of protein was separated on 8% SDS-polyacrylamide gel electrophoresis and TRPV1-immunoreactivity was determined using a polyclonal anti-TRPV1 antibody. The blot is representative of five separate experiments with similar results. (C) Quantitative analysis of TRPV1 between DRG and SMG in mice by real-time PCR. TRPV1 mRNA levels are represented as ratios to the mRNA level of the housekeeping gene, GAPDH. Results are presented as mean±SD (n=4, **p<.001).
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Figure 1: Expression of TRPV1 in salivary gland epithelial cells (SGEC). (A) Expression of TRPV1 mRNA in mouse SMG (mSMG), human SMG (hSMG), and HSG cells by RT-PCR, with GAPDH as an internal control. (B) Expression of TRPV1 protein in mSMG, hSMG, and HSG cells by Western blot. Approximately 50 µg of protein was separated on 8% SDS-polyacrylamide gel electrophoresis and TRPV1-immunoreactivity was determined using a polyclonal anti-TRPV1 antibody. The blot is representative of five separate experiments with similar results. (C) Quantitative analysis of TRPV1 between DRG and SMG in mice by real-time PCR. TRPV1 mRNA levels are represented as ratios to the mRNA level of the housekeeping gene, GAPDH. Results are presented as mean±SD (n=4, **p<.001).

Mentions: We first examined whether TRPV1 genes are expressed in mouse DRG, mSMG, hSMG, and HSG cells using RT-PCR. The mRNA transcripts of TRPV1 were detected from DRG and SMG in mice (left panel in Fig. 1A) as well as in hSMG and HSG cells (right panel in Fig. 1A). In this experiment, mouse DRG was used as positive controls. We also performed Western blot analysis to confirm TRPV1 expression at the protein level in these tissues. A band with a molecular mass of approximately 95 kDa corresponding to TRPV1 from mSMG (left panel in Fig. 1B), and hSMG and HSG cells was found (right panel in Fig. 1B). However, the expression levels of TRPV1 were different between DRG and SMG in mice. Our real-time PCR data shows 1.067±0.025 (n=4) and 0.169±0.018 (n=4) in DRG and SMG, respectively (Fig. 1C). The results demonstrate that expression level of TRPV1 in mSMG is very low compared to that of DRG.


TRPV1 in Salivary Gland Epithelial Cells Is Not Involved in Salivary Secretion via Transcellular Pathway.

Choi S, Shin YH, Namkoong E, Hwang SM, Cong X, Yu G, Park K - Korean J. Physiol. Pharmacol. (2014)

Expression of TRPV1 in salivary gland epithelial cells (SGEC). (A) Expression of TRPV1 mRNA in mouse SMG (mSMG), human SMG (hSMG), and HSG cells by RT-PCR, with GAPDH as an internal control. (B) Expression of TRPV1 protein in mSMG, hSMG, and HSG cells by Western blot. Approximately 50 µg of protein was separated on 8% SDS-polyacrylamide gel electrophoresis and TRPV1-immunoreactivity was determined using a polyclonal anti-TRPV1 antibody. The blot is representative of five separate experiments with similar results. (C) Quantitative analysis of TRPV1 between DRG and SMG in mice by real-time PCR. TRPV1 mRNA levels are represented as ratios to the mRNA level of the housekeeping gene, GAPDH. Results are presented as mean±SD (n=4, **p<.001).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4296043&req=5

Figure 1: Expression of TRPV1 in salivary gland epithelial cells (SGEC). (A) Expression of TRPV1 mRNA in mouse SMG (mSMG), human SMG (hSMG), and HSG cells by RT-PCR, with GAPDH as an internal control. (B) Expression of TRPV1 protein in mSMG, hSMG, and HSG cells by Western blot. Approximately 50 µg of protein was separated on 8% SDS-polyacrylamide gel electrophoresis and TRPV1-immunoreactivity was determined using a polyclonal anti-TRPV1 antibody. The blot is representative of five separate experiments with similar results. (C) Quantitative analysis of TRPV1 between DRG and SMG in mice by real-time PCR. TRPV1 mRNA levels are represented as ratios to the mRNA level of the housekeeping gene, GAPDH. Results are presented as mean±SD (n=4, **p<.001).
Mentions: We first examined whether TRPV1 genes are expressed in mouse DRG, mSMG, hSMG, and HSG cells using RT-PCR. The mRNA transcripts of TRPV1 were detected from DRG and SMG in mice (left panel in Fig. 1A) as well as in hSMG and HSG cells (right panel in Fig. 1A). In this experiment, mouse DRG was used as positive controls. We also performed Western blot analysis to confirm TRPV1 expression at the protein level in these tissues. A band with a molecular mass of approximately 95 kDa corresponding to TRPV1 from mSMG (left panel in Fig. 1B), and hSMG and HSG cells was found (right panel in Fig. 1B). However, the expression levels of TRPV1 were different between DRG and SMG in mice. Our real-time PCR data shows 1.067±0.025 (n=4) and 0.169±0.018 (n=4) in DRG and SMG, respectively (Fig. 1C). The results demonstrate that expression level of TRPV1 in mSMG is very low compared to that of DRG.

Bottom Line: However, capsaicin (CAP), TRPV1 agonist, had little effect on intracellular free calcium concentration ([Ca(2+)]i) in these cells, although carbachol consistently increased [Ca(2+)]i.Saliva flow rate also showed insignificant change in the mice treated with PILO plus CAP compared with that in mice treated with PILO alone.Taken together, our results suggest that although TRPV1 is expressed in SGEC, it appears not to play any direct roles in saliva secretion via transcellular pathway.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, School of Dentistry, Seoul National University and Dental Research Institute, Seoul 110-749, Korea.

ABSTRACT
Transient receptor potential vanilloid subtype 1 (TRPV1) was originally found in sensory neurons. Recently, it has been reported that TRPV1 is expressed in salivary gland epithelial cells (SGEC). However, the physiological role of TRPV1 in salivary secretion remains to be elucidated. We found that TRPV1 is expressed in mouse and human submandibular glands (SMG) and HSG cells, originated from human submandibular gland ducts at both mRNA and protein levels. However, capsaicin (CAP), TRPV1 agonist, had little effect on intracellular free calcium concentration ([Ca(2+)]i) in these cells, although carbachol consistently increased [Ca(2+)]i. Exposure of cells to high temperature (>43℃) or acidic bath solution (pH5.4) did not increase [Ca(2+)]i, either. We further examined the role of TRPV1 in salivary secretion using TRPV1 knock-out mice. There was no significant difference in the pilocarpine (PILO)-induced salivary flow rate between wild-type and TRPV1 knock-out mice. Saliva flow rate also showed insignificant change in the mice treated with PILO plus CAP compared with that in mice treated with PILO alone. Taken together, our results suggest that although TRPV1 is expressed in SGEC, it appears not to play any direct roles in saliva secretion via transcellular pathway.

No MeSH data available.


Related in: MedlinePlus