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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

BDNF activates JAK/STAT directly. The HSC and RT4-D6P2T cells were validated by immunofluorescence staining. (A) The cellular markers of Schwann cells, S100 and p75, were expressed in cells in the cytoplasm represented as green (FTIC) and nucleus as blue (DAPI) (×100); (B,C) different doses of BDNF were applied to treat BE(2)-C, SH-SY5Y and RT4-D6P2T (0, 1, 10, 100 pM) for 30 minutes. The phosphorylation of STAT3/STAT1 was extensively enhanced by BDNF at a dose of (100 pM) in RT4-D6P2T cells (*P<0.01), while the activation level of JAK/STAT did not change in the same conditions in human neuroblastoma cell lines BE(2)-C and SH-SY5Y. Three independent experiments were done for each data point, and the error bars represent ± SD. BDNF, brain-derived neurotrophic factor; JAK, Janus kinase; STAT, signal transducer and activator of transcription; HSC, human Schwann cell.
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f1: BDNF activates JAK/STAT directly. The HSC and RT4-D6P2T cells were validated by immunofluorescence staining. (A) The cellular markers of Schwann cells, S100 and p75, were expressed in cells in the cytoplasm represented as green (FTIC) and nucleus as blue (DAPI) (×100); (B,C) different doses of BDNF were applied to treat BE(2)-C, SH-SY5Y and RT4-D6P2T (0, 1, 10, 100 pM) for 30 minutes. The phosphorylation of STAT3/STAT1 was extensively enhanced by BDNF at a dose of (100 pM) in RT4-D6P2T cells (*P<0.01), while the activation level of JAK/STAT did not change in the same conditions in human neuroblastoma cell lines BE(2)-C and SH-SY5Y. Three independent experiments were done for each data point, and the error bars represent ± SD. BDNF, brain-derived neurotrophic factor; JAK, Janus kinase; STAT, signal transducer and activator of transcription; HSC, human Schwann cell.

Mentions: To validate the Schwann cell, the specific cellular markers S100 and p75 were checked by immunofluorescence staining in HSCs and RSCs RT4-D6P2T cells. The result indicated that both those cells expressed S100 and p75 in the cytoplasm, although the expression level and location are different. The HSCs expressed more S100 and p75, while the RSCs RT4-D6P2T shaped as small spindle-like cells and expressed peri-nucleus S100 (Figure 1A).


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)

BDNF activates JAK/STAT directly. The HSC and RT4-D6P2T cells were validated by immunofluorescence staining. (A) The cellular markers of Schwann cells, S100 and p75, were expressed in cells in the cytoplasm represented as green (FTIC) and nucleus as blue (DAPI) (×100); (B,C) different doses of BDNF were applied to treat BE(2)-C, SH-SY5Y and RT4-D6P2T (0, 1, 10, 100 pM) for 30 minutes. The phosphorylation of STAT3/STAT1 was extensively enhanced by BDNF at a dose of (100 pM) in RT4-D6P2T cells (*P<0.01), while the activation level of JAK/STAT did not change in the same conditions in human neuroblastoma cell lines BE(2)-C and SH-SY5Y. Three independent experiments were done for each data point, and the error bars represent ± SD. BDNF, brain-derived neurotrophic factor; JAK, Janus kinase; STAT, signal transducer and activator of transcription; HSC, human Schwann cell.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4837308&req=5

f1: BDNF activates JAK/STAT directly. The HSC and RT4-D6P2T cells were validated by immunofluorescence staining. (A) The cellular markers of Schwann cells, S100 and p75, were expressed in cells in the cytoplasm represented as green (FTIC) and nucleus as blue (DAPI) (×100); (B,C) different doses of BDNF were applied to treat BE(2)-C, SH-SY5Y and RT4-D6P2T (0, 1, 10, 100 pM) for 30 minutes. The phosphorylation of STAT3/STAT1 was extensively enhanced by BDNF at a dose of (100 pM) in RT4-D6P2T cells (*P<0.01), while the activation level of JAK/STAT did not change in the same conditions in human neuroblastoma cell lines BE(2)-C and SH-SY5Y. Three independent experiments were done for each data point, and the error bars represent ± SD. BDNF, brain-derived neurotrophic factor; JAK, Janus kinase; STAT, signal transducer and activator of transcription; HSC, human Schwann cell.
Mentions: To validate the Schwann cell, the specific cellular markers S100 and p75 were checked by immunofluorescence staining in HSCs and RSCs RT4-D6P2T cells. The result indicated that both those cells expressed S100 and p75 in the cytoplasm, although the expression level and location are different. The HSCs expressed more S100 and p75, while the RSCs RT4-D6P2T shaped as small spindle-like cells and expressed peri-nucleus S100 (Figure 1A).

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