Ryuji Tamura1, Takayuki Nemoto, Toyoaki Maruta, Shin Onizuka, Toshihiko Yanagita, Akihiko Wada, Manabu Murakami, Isao Tsuneyoshi. 1. From the Departments of *Anesthesiology and Intensive Care and †Pharmacology, Miyazaki Medical College, University of Miyazaki, Miyazaki, Japan; ‡Department of Anesthesiology, Division of Basic Research, Washington University School of Medicine, St. Louis, Missouri; §Department of Sports Health and Welfare, Faculty of Social Welfare, Kyusyu University of Health and Welfare, Miyazaki, Japan.
Abstract
BACKGROUND: Tumor necrosis factor-α (TNF-α) is not only a key regulator of inflammatory response but also an important pain modulator. TNF-α enhances both tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant Na channel currents in dorsal root ganglion (DRG) neurons. However, it remains unknown whether TNF-α affects the function and expression of the TTX-S NaV1.7 Na channel, which plays crucial roles in pain generation. METHODS: We used cultured bovine adrenal chromaffin cells expressing the NaV1.7 Na channel isoform and compared them with cultured rat DRG neurons. The expression of TNF receptor 1 and 2 (TNFR1 and TNFR2) in adrenal chromaffin cells was studied by Semiquantitative reverse transcription-polymerase chain reaction. The effects of TNF-α on the expression of NaV1.7 were examined with reverse transcription-polymerase chain reaction and Western blot analysis. Results were expressed as mean ± SEM. RESULTS: TNFR1 and TNFR2 were expressed in adrenal chromaffin cells, as well as reported in DRG neurons. TNF-α up-regulated NaV1.7 mRNA by 132% ± 9% (N = 5, P = 0.004) in adrenal chromaffin cells, as well as 117% ± 2% (N = 5, P < 0.0001) in DRG neurons. Western blot analysis showed that TNF-α increased NaV1.7 protein up to 166% ± 24% (N = 5, corrected P < 0.0001) in adrenal chromaffin cells, concentration- and time-dependently. CONCLUSIONS: TNF-α up-regulated NaV1.7 mRNA in both adrenal chromaffin cells and DRG neurons. In addition, TNF-α up-regulated the protein expression of the TTX-S NaV1.7 channel in adrenal chromaffin cells. Our findings may contribute to understanding the peripheral nociceptive mechanism of TNF-α.
BACKGROUND: Tumor necrosis factor-α (TNF-α) is not only a key regulator of inflammatory response but also an important pain modulator. TNF-α enhances both tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant Na channel currents in dorsal root ganglion (DRG) neurons. However, it remains unknown whether TNF-α affects the function and expression of the TTX-SNaV1.7 Na channel, which plays crucial roles in pain generation. METHODS: We used cultured bovine adrenal chromaffin cells expressing the NaV1.7 Na channel isoform and compared them with cultured rat DRG neurons. The expression of TNF receptor 1 and 2 (TNFR1 and TNFR2) in adrenal chromaffin cells was studied by Semiquantitative reverse transcription-polymerase chain reaction. The effects of TNF-α on the expression of NaV1.7 were examined with reverse transcription-polymerase chain reaction and Western blot analysis. Results were expressed as mean ± SEM. RESULTS:TNFR1 and TNFR2 were expressed in adrenal chromaffin cells, as well as reported in DRG neurons. TNF-α up-regulated NaV1.7 mRNA by 132% ± 9% (N = 5, P = 0.004) in adrenal chromaffin cells, as well as 117% ± 2% (N = 5, P < 0.0001) in DRG neurons. Western blot analysis showed that TNF-α increased NaV1.7 protein up to 166% ± 24% (N = 5, corrected P < 0.0001) in adrenal chromaffin cells, concentration- and time-dependently. CONCLUSIONS: TNF-α up-regulated NaV1.7 mRNA in both adrenal chromaffin cells and DRG neurons. In addition, TNF-α up-regulated the protein expression of the TTX-SNaV1.7 channel in adrenal chromaffin cells. Our findings may contribute to understanding the peripheral nociceptive mechanism of TNF-α.
Authors: Rahul R Atmaramani; Bryan J Black; June Bryan de la Peña; Zachary T Campbell; Joseph J Pancrazio Journal: Bioengineering (Basel) Date: 2020-05-16