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Brain-derived neurotrophic factor promotes nerve regeneration by activating the JAK/STAT pathway in Schwann cells.

Lin G, Zhang H, Sun F, Lu Z, Reed-Maldonado A, Lee YC, Wang G, Banie L, Lue TF - Transl Androl Urol (2016)

Bottom Line: We hypothesize that brain-derived neurotrophic factor (BDNF) activates the Janus kinase (JAK)/(signal transducer and activator of transcription) STAT pathway in Schwann cells, not in neuronal axonal fibers, with the resultant secretion of cytokines from Schwann cells to facilitate nerve recovery.We demonstrated for the first time the indirect mechanism of BDNF enhancement of nerve regeneration through the activation of JAK/STAT pathway in Schwann cells, rather than directly on neurons.As a result of BDNF application, Schwann cells produce cytokines that promote nerve regeneration.

View Article: PubMed Central - PubMed

Affiliation: 1 Knuppe Molecular Urology Laboratory, Department of Urology, School of Medicine, University of California, San Francisco, CA, USA ; 2 Minimally Invasive Urology Center, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250012, China ; 3 Department of Urology, The First Hospital of Jilin University, Changchun 130021, China ; 4 Department of Urology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.

ABSTRACT

Background: Radical prostatectomy (RP) carries the risk of erectile dysfunction (ED) due to cavernous nerve (CN) injury. Schwann cells are essential for the maintenance of integrity and function of peripheral nerves such as the CNs. We hypothesize that brain-derived neurotrophic factor (BDNF) activates the Janus kinase (JAK)/(signal transducer and activator of transcription) STAT pathway in Schwann cells, not in neuronal axonal fibers, with the resultant secretion of cytokines from Schwann cells to facilitate nerve recovery.

Methods: Using four different cell lines-human neuroblastoma BE(2)-C and SH-SY5Y, human Schwann cell (HSC), and rat Schwann cell (RSC) RT4-D6P2T-we assessed the effect of BDNF application on the activation of the JAK/STAT pathway. We also assessed the time response of JAK/STAT pathway activation in RSCs and HSCs after BDNF treatment. We then assayed cytokine release from HSCs as a response to BDNF treatment using oncostatin M and IL6 as markers.

Results: We showed extensive phosphorylation of STAT3/STAT1 by BDNF at high dose (100 pM) in RSCs, with no JAK/STAT pathway activation in human neuroblastoma cell lines. The time response of JAK/STAT pathway activation in RSCs and HSCs after BDNF treatment showed an initial peak at shortly after treatment and then a second higher peak at 24-48 hours. Cytokine release from HSCs increased progressively after BDNF application, reaching statistical significance for IL6.

Conclusions: We demonstrated for the first time the indirect mechanism of BDNF enhancement of nerve regeneration through the activation of JAK/STAT pathway in Schwann cells, rather than directly on neurons. As a result of BDNF application, Schwann cells produce cytokines that promote nerve regeneration.

No MeSH data available.


Related in: MedlinePlus

Mechanism of JAK/STAT re-activation by BDNF in HSCs. BDNF (100 pM) was administered to treat the human Schwann cell HSCs for 0 min, 10 min, 30 min, 60 min, 120 min, 24 hr, 48 hr, and 72 hr. (A) JAK2 was activated by BDNF treatment and possessed two phosphorylation peaks, which was similar to the response of STAT3/STAT1; (B) the phosphorylation levels of JAK2, STAT1 and STAT3 were presented as a ratio of phosphorylated form to total expressed forms. P1: phosphorylation early peak. P2: phosphorylation late peak. The cell culture mediums from the above treatment were applied to assay the level of cytokines secreted from HSCs by ELISA; (C) 1 hr after the BDNF treatment, HSCs began to secrete OSM-M at levels reaching ~20±0.8 pg/mL at 24 hr (#P>0.05); (D) BDNF significantly increased the secretion of IL6 from HSCs after 1 hr of the treatment and reached ~360.9±74 pg/mL at 72 hr (*P<0.01). Three independent experiments were done for each data point, and the error bars represent ± SD. JAK, Janus kinase; STAT, signal transducer and activator of transcription; HSCs, human Schwann cells; BDNF, brain-derived neurotrophic factor; ELISA, enzyme linked immunosorbent assay.
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f4: Mechanism of JAK/STAT re-activation by BDNF in HSCs. BDNF (100 pM) was administered to treat the human Schwann cell HSCs for 0 min, 10 min, 30 min, 60 min, 120 min, 24 hr, 48 hr, and 72 hr. (A) JAK2 was activated by BDNF treatment and possessed two phosphorylation peaks, which was similar to the response of STAT3/STAT1; (B) the phosphorylation levels of JAK2, STAT1 and STAT3 were presented as a ratio of phosphorylated form to total expressed forms. P1: phosphorylation early peak. P2: phosphorylation late peak. The cell culture mediums from the above treatment were applied to assay the level of cytokines secreted from HSCs by ELISA; (C) 1 hr after the BDNF treatment, HSCs began to secrete OSM-M at levels reaching ~20±0.8 pg/mL at 24 hr (#P>0.05); (D) BDNF significantly increased the secretion of IL6 from HSCs after 1 hr of the treatment and reached ~360.9±74 pg/mL at 72 hr (*P<0.01). Three independent experiments were done for each data point, and the error bars represent ± SD. JAK, Janus kinase; STAT, signal transducer and activator of transcription; HSCs, human Schwann cells; BDNF, brain-derived neurotrophic factor; ELISA, enzyme linked immunosorbent assay.

Mentions: At the same time, activation of JAK2 was also confirmed (Figure 4A). JAK2 was activated by BDNF treatment and consisted of two phosphorylation peaks, which was similar to the response of STAT3/STAT1. All those three major molecules in the JAK/STAT pathway, JAK2, STAT1 and STAT3, possessed the same phosphorylation pattern when treated by BDNF in HSCs—an early phosphorylation peak (P1) and a later phosphorylation peak (P2) (Figure 4B).


Brain-derived neurotrophic factor promotes nerve regeneration by activating the JAK/STAT pathway in Schwann cells.

Lin G, Zhang H, Sun F, Lu Z, Reed-Maldonado A, Lee YC, Wang G, Banie L, Lue TF - Transl Androl Urol (2016)

Mechanism of JAK/STAT re-activation by BDNF in HSCs. BDNF (100 pM) was administered to treat the human Schwann cell HSCs for 0 min, 10 min, 30 min, 60 min, 120 min, 24 hr, 48 hr, and 72 hr. (A) JAK2 was activated by BDNF treatment and possessed two phosphorylation peaks, which was similar to the response of STAT3/STAT1; (B) the phosphorylation levels of JAK2, STAT1 and STAT3 were presented as a ratio of phosphorylated form to total expressed forms. P1: phosphorylation early peak. P2: phosphorylation late peak. The cell culture mediums from the above treatment were applied to assay the level of cytokines secreted from HSCs by ELISA; (C) 1 hr after the BDNF treatment, HSCs began to secrete OSM-M at levels reaching ~20±0.8 pg/mL at 24 hr (#P>0.05); (D) BDNF significantly increased the secretion of IL6 from HSCs after 1 hr of the treatment and reached ~360.9±74 pg/mL at 72 hr (*P<0.01). Three independent experiments were done for each data point, and the error bars represent ± SD. JAK, Janus kinase; STAT, signal transducer and activator of transcription; HSCs, human Schwann cells; BDNF, brain-derived neurotrophic factor; ELISA, enzyme linked immunosorbent assay.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4837308&req=5

f4: Mechanism of JAK/STAT re-activation by BDNF in HSCs. BDNF (100 pM) was administered to treat the human Schwann cell HSCs for 0 min, 10 min, 30 min, 60 min, 120 min, 24 hr, 48 hr, and 72 hr. (A) JAK2 was activated by BDNF treatment and possessed two phosphorylation peaks, which was similar to the response of STAT3/STAT1; (B) the phosphorylation levels of JAK2, STAT1 and STAT3 were presented as a ratio of phosphorylated form to total expressed forms. P1: phosphorylation early peak. P2: phosphorylation late peak. The cell culture mediums from the above treatment were applied to assay the level of cytokines secreted from HSCs by ELISA; (C) 1 hr after the BDNF treatment, HSCs began to secrete OSM-M at levels reaching ~20±0.8 pg/mL at 24 hr (#P>0.05); (D) BDNF significantly increased the secretion of IL6 from HSCs after 1 hr of the treatment and reached ~360.9±74 pg/mL at 72 hr (*P<0.01). Three independent experiments were done for each data point, and the error bars represent ± SD. JAK, Janus kinase; STAT, signal transducer and activator of transcription; HSCs, human Schwann cells; BDNF, brain-derived neurotrophic factor; ELISA, enzyme linked immunosorbent assay.
Mentions: At the same time, activation of JAK2 was also confirmed (Figure 4A). JAK2 was activated by BDNF treatment and consisted of two phosphorylation peaks, which was similar to the response of STAT3/STAT1. All those three major molecules in the JAK/STAT pathway, JAK2, STAT1 and STAT3, possessed the same phosphorylation pattern when treated by BDNF in HSCs—an early phosphorylation peak (P1) and a later phosphorylation peak (P2) (Figure 4B).

Bottom Line: We hypothesize that brain-derived neurotrophic factor (BDNF) activates the Janus kinase (JAK)/(signal transducer and activator of transcription) STAT pathway in Schwann cells, not in neuronal axonal fibers, with the resultant secretion of cytokines from Schwann cells to facilitate nerve recovery.We demonstrated for the first time the indirect mechanism of BDNF enhancement of nerve regeneration through the activation of JAK/STAT pathway in Schwann cells, rather than directly on neurons.As a result of BDNF application, Schwann cells produce cytokines that promote nerve regeneration.

View Article: PubMed Central - PubMed

Affiliation: 1 Knuppe Molecular Urology Laboratory, Department of Urology, School of Medicine, University of California, San Francisco, CA, USA ; 2 Minimally Invasive Urology Center, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250012, China ; 3 Department of Urology, The First Hospital of Jilin University, Changchun 130021, China ; 4 Department of Urology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.

ABSTRACT

Background: Radical prostatectomy (RP) carries the risk of erectile dysfunction (ED) due to cavernous nerve (CN) injury. Schwann cells are essential for the maintenance of integrity and function of peripheral nerves such as the CNs. We hypothesize that brain-derived neurotrophic factor (BDNF) activates the Janus kinase (JAK)/(signal transducer and activator of transcription) STAT pathway in Schwann cells, not in neuronal axonal fibers, with the resultant secretion of cytokines from Schwann cells to facilitate nerve recovery.

Methods: Using four different cell lines-human neuroblastoma BE(2)-C and SH-SY5Y, human Schwann cell (HSC), and rat Schwann cell (RSC) RT4-D6P2T-we assessed the effect of BDNF application on the activation of the JAK/STAT pathway. We also assessed the time response of JAK/STAT pathway activation in RSCs and HSCs after BDNF treatment. We then assayed cytokine release from HSCs as a response to BDNF treatment using oncostatin M and IL6 as markers.

Results: We showed extensive phosphorylation of STAT3/STAT1 by BDNF at high dose (100 pM) in RSCs, with no JAK/STAT pathway activation in human neuroblastoma cell lines. The time response of JAK/STAT pathway activation in RSCs and HSCs after BDNF treatment showed an initial peak at shortly after treatment and then a second higher peak at 24-48 hours. Cytokine release from HSCs increased progressively after BDNF application, reaching statistical significance for IL6.

Conclusions: We demonstrated for the first time the indirect mechanism of BDNF enhancement of nerve regeneration through the activation of JAK/STAT pathway in Schwann cells, rather than directly on neurons. As a result of BDNF application, Schwann cells produce cytokines that promote nerve regeneration.

No MeSH data available.


Related in: MedlinePlus