TY - JOUR
T1 - Discovery of Exosomes From Tick Saliva and Salivary Glands Reveals Therapeutic Roles for CXCL12 and IL-8 in Wound Healing at the Tick–Human Skin Interface
AU - Zhou, Wenshuo
AU - Tahir, Faizan
AU - Wang, Joseph Che Yen
AU - Woodson, Michael
AU - Sherman, Michael B.
AU - Karim, Shahid
AU - Neelakanta, Girish
AU - Sultana, Hameeda
N1 - Funding Information:
HS would like to sincerely acknowledge the kind support from BEI resources. The following reagent was provided by the Centers for Disease Control and Prevention for distribution by BEI Resources, NIAID, and NIH: Ixodes scapularis Adult (Live), NR-42510. HS and GN would like to sincerely acknowledge the generous support from Dr. Jean-Luc Fraikin and Lew Brown from Spectradyne LLC to help estimate the tick saliva and salivary gland exosome numbers. Lew Brown performed the particle measurement analysis for both saliva and salivary gland-derived exosomes, and we are extremely thankful for his time and support. Funding. Work on Amblyomma maculatum ticks blood feeding on sheep, generation of tick saliva and salivary glands was supported by awards from the National Institutes of General Medical Sciences #GM103476, USDA NIFA award #2017-67017-26171, and US Department of State award #2017-67016-26864 to SK. HS and GN would like to acknowledge the generous support from the National Institutes of Health (NIH)/National Institute of Allergy and Infectious Diseases (NIAID) for the Award (R01AI141790, PI: HS).
Publisher Copyright:
© Copyright © 2020 Zhou, Tahir, Wang, Woodson, Sherman, Karim, Neelakanta and Sultana.
PY - 2020/7/16
Y1 - 2020/7/16
N2 - Ticks secrete various anti-coagulatory, anti-vasoconstrictory, anti-inflammatory, and anti-platelet aggregation factors in their saliva at the bite site during feeding to evade host immunological surveillance and responses. For the first time, we report successful isolation of exosomes (small membrane-bound extracellular signaling vesicles) from saliva and salivary glands of partially fed or unfed ixodid ticks. Our data showed a novel role of these in vivo exosomes in the inhibition of wound healing via downregulation of C-X-C motif chemokine ligand 12 (CXCL12) and upregulation of interleukin-8 (IL-8). Cryo-electron microscopy (cryo-EM) analysis revealed that tick saliva and salivary glands are composed of heterogeneous populations of in vivo exosomes with sizes ranging from 30 to 200 nm. Enriched amounts of tick CD63 ortholog protein and heat shock protein 70 (HSP70) were evident in these exosomes. Treatment of human skin keratinocytes (HaCaT cells) with exosomes derived from tick saliva/salivary glands or ISE6 cells dramatically delayed cell migration, wound healing, and repair process. Wound healing is a highly dynamic process with several individualized processes including secretion of cytokines. Cytokine array profiling followed by immunoblotting and quantitative-PCR analysis revealed that HaCaT cells treated with exosomes derived from tick saliva/salivary glands or ISE6 cells showed enhanced IL-8 levels and reduced CXCL12 loads. Inhibition of IL-8 or CXCL12 further delayed exosome-mediated cell migration, wound healing, and repair process, suggesting a skin barrier protection role for these chemokines at the tick bite site. In contrast, exogenous treatment of CXCL12 protein completely restored this delay and enhanced the repair process. Taken together, our study provides novel insights on how tick salivary exosomes secreted in saliva can delay wound healing at the bite site to facilitate successful blood feeding.
AB - Ticks secrete various anti-coagulatory, anti-vasoconstrictory, anti-inflammatory, and anti-platelet aggregation factors in their saliva at the bite site during feeding to evade host immunological surveillance and responses. For the first time, we report successful isolation of exosomes (small membrane-bound extracellular signaling vesicles) from saliva and salivary glands of partially fed or unfed ixodid ticks. Our data showed a novel role of these in vivo exosomes in the inhibition of wound healing via downregulation of C-X-C motif chemokine ligand 12 (CXCL12) and upregulation of interleukin-8 (IL-8). Cryo-electron microscopy (cryo-EM) analysis revealed that tick saliva and salivary glands are composed of heterogeneous populations of in vivo exosomes with sizes ranging from 30 to 200 nm. Enriched amounts of tick CD63 ortholog protein and heat shock protein 70 (HSP70) were evident in these exosomes. Treatment of human skin keratinocytes (HaCaT cells) with exosomes derived from tick saliva/salivary glands or ISE6 cells dramatically delayed cell migration, wound healing, and repair process. Wound healing is a highly dynamic process with several individualized processes including secretion of cytokines. Cytokine array profiling followed by immunoblotting and quantitative-PCR analysis revealed that HaCaT cells treated with exosomes derived from tick saliva/salivary glands or ISE6 cells showed enhanced IL-8 levels and reduced CXCL12 loads. Inhibition of IL-8 or CXCL12 further delayed exosome-mediated cell migration, wound healing, and repair process, suggesting a skin barrier protection role for these chemokines at the tick bite site. In contrast, exogenous treatment of CXCL12 protein completely restored this delay and enhanced the repair process. Taken together, our study provides novel insights on how tick salivary exosomes secreted in saliva can delay wound healing at the bite site to facilitate successful blood feeding.
KW - C-X-C motif chemokine ligand 12 (CXCL12)
KW - exosomes
KW - interleukin-8 (IL-8)
KW - saliva
KW - salivary glands
KW - skin barrier
KW - ticks
KW - wound healing
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UR - http://www.scopus.com/inward/citedby.url?scp=85088800706&partnerID=8YFLogxK
U2 - 10.3389/fcell.2020.00554
DO - 10.3389/fcell.2020.00554
M3 - Article
AN - SCOPUS:85088800706
VL - 8
JO - Frontiers in Cell and Developmental Biology
JF - Frontiers in Cell and Developmental Biology
SN - 2296-634X
M1 - 554
ER -