Adipose tissue-derived stem cells secrete CXCL5 cytokine with neurotrophic effects on cavernous nerve regeneration.
BACKGROUND
Previously we reported that paracrine actions likely mediated the therapeutic effects of adipose tissue-derived stem cells (ADSCs) on a rat model of cavernous nerve (CN) injury.


OBJECTIVE
To identify potential neurotrophic factors in ADSC's secretion, test the most promising one, and identify the molecular mechanism of its neurotrophic action.


METHODS
Rat major pelvic ganglia (MPG) were cultured in conditioned media of ADSC and penile smooth muscle cells (PSMCs). Cytokine expression in these two media was probed with a cytokine antibody array. CXCL5 cytokine was quantified in these two media by enzyme-linked immunosorbent assay (ELISA). Activation of Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) by CXCL5 was tested in neuroblastoma cell lines BE(2)C and SH-SY5Y as well as in Schwann cell line RT4-D6P2T by Western blot. Involvement of CXCL5 and JAK/STAT in ADSC-conditioned medium's neurotrophic effects was confirmed with anti-CXCL5 antibody and JAK inhibitor AG490, respectively.


METHODS
Neurotrophic effects of ADSC and PSMC-conditioned media were quantified by measuring neurite length in MPG cultures. Secretion of CXCL5 in these two media was quantified by ELISA. Activation of JAK/STAT by CXCL5 was quantified by densitometry on Western blots for STAT1 and STAT3 phosphorylation.


RESULTS
MPG neurite length was significantly longer in ADSC than in PSMC-conditioned medium. CXCL5 was secreted eight times higher in ADSC than in PSMC-conditioned medium. Anti-CXCL5 antibody blocked the neurotrophic effects of ADSC-conditioned medium. CXCL5 activated JAK/STAT concentration-dependently from 0 to 50 ng/mL in RT4-D6P2T Schwann cells. At 50 ng/mL, CXCL5 activated JAK/STAT time-dependently, peaking at 45 minutes. AG490 blocked these activities as well as the neurotrophic effects of ADSC-conditioned medium.


CONCLUSIONS
CXCL5 was secreted by ADSC at a high level, promoted MPG neurite growth, and activated JAK/STAT in Schwann cells. CXCL5 may contribute to ADSC's therapeutic efficacy on CN injury-induced ED.
Knuppe Molecular Urology Laboratory-Department of Urology, School of Medicine, University of California, San Francisco, CA 94143, USA.
Haiyang
H
Zhang
Rong
R
Yang
Zhong
Z
Wang
Guiting
G
Lin
Tom F
TF
Lue
Ching-Shwun
CS
Lin
D000273:Adipose Tissue / Q000166:cytology*; D000818:Animals; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D054365:Chemokine CXCL5 / Q000494:pharmacology / Q000502:physiology*; D004789:Enzyme Activation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D053612:Janus Kinases / Q000378:metabolism; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000294:innervation / Q000502:physiology; D009416:Nerve Regeneration / Q000187:drug effects / Q000502:physiology*; D016501:Neurites / Q000187:drug effects / Q000502:physiology; D010413:Penis / Q000294:innervation* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D050791:STAT Transcription Factors / Q000378:metabolism; D012583:Schwann Cells / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013234:Stem Cells / Q000378:metabolism* / Q000502:physiology
D054365:Chemokine CXCL5; D050791:STAT Transcription Factors; D053612:Janus Kinases