TY - JOUR
T1 - New insights into mechanisms and functions of chemokine (C-X-C motif) receptor 4 heteromerization in vascular smooth muscle
AU - Evans, Ann E.
AU - Tripathi, Abhishek
AU - LaPorte, Heather M.
AU - Brueggemann, Lioubov I.
AU - Singh, Abhay Kumar
AU - Albee, Lauren J.
AU - Byron, Kenneth L.
AU - Tarasova, Nadya I.
AU - Volkman, Brian F.
AU - Cho, Thomas Yoonsang
AU - Gaponenko, Vadim
AU - Majetschak, Matthias
N1 - Publisher Copyright:
© 2016 by the authors; licensee MDPI, Basel, Switzerland.
PY - 2016/6/20
Y1 - 2016/6/20
N2 - Recent evidence suggests that C-X-C chemokine receptor type 4 (CXCR4) heteromerizes with α1A/B-adrenoceptors (AR) and atypical chemokine receptor 3 (ACKR3) and that CXCR4:α1A/B-AR heteromers are important for α1-AR function in vascular smooth muscle cells (VSMC). Structural determinants for CXCR4 heteromerization and functional consequences of CXCR4: α heteromerization in intact arteries, however, remain unknown. Utilizing proximity ligation assays (PLA) to visualize receptor interactions in VSMC, we show that peptide analogs of transmembrane-domain (TM) 2 and TM4 of CXCR4 selectively reduce PLA signals for CXCR4: α1A-AR and CXCR4:ACKR3 interactions, respectively. While both peptides inhibit CXCL12-induced chemotaxis, only the TM2 peptide inhibits phenylephrine-induced Ca2+-fluxes, contraction of VSMC and reduces efficacy of phenylephrine to constrict isolated arteries. In a Cre-loxP mouse model to delete CXCR4 in VSMC, we observed 60% knockdown of CXCR4. PLA signals for CXCR4: α1A/B-AR and CXCR4:ACKR3 interactions in VSMC, however, remained constant. Our observations point towards TM2/4 of CXCR4 as possible contact sites for heteromerization and suggest that TM-derived peptide analogs permit selective targeting of CXCR4 heteromers. A molecular dynamics simulation of a receptor complex in which the CXCR4 homodimer interacts with α1A-AR via TM2 and with ACKR3 via TM4 is presented. Our findings further imply that CXCR4: α1A-AR heteromers are important for intrinsic α1-AR function in intact arteries and provide initial and unexpected insights into the regulation of CXCR4 heteromerization in VSMC.
AB - Recent evidence suggests that C-X-C chemokine receptor type 4 (CXCR4) heteromerizes with α1A/B-adrenoceptors (AR) and atypical chemokine receptor 3 (ACKR3) and that CXCR4:α1A/B-AR heteromers are important for α1-AR function in vascular smooth muscle cells (VSMC). Structural determinants for CXCR4 heteromerization and functional consequences of CXCR4: α heteromerization in intact arteries, however, remain unknown. Utilizing proximity ligation assays (PLA) to visualize receptor interactions in VSMC, we show that peptide analogs of transmembrane-domain (TM) 2 and TM4 of CXCR4 selectively reduce PLA signals for CXCR4: α1A-AR and CXCR4:ACKR3 interactions, respectively. While both peptides inhibit CXCL12-induced chemotaxis, only the TM2 peptide inhibits phenylephrine-induced Ca2+-fluxes, contraction of VSMC and reduces efficacy of phenylephrine to constrict isolated arteries. In a Cre-loxP mouse model to delete CXCR4 in VSMC, we observed 60% knockdown of CXCR4. PLA signals for CXCR4: α1A/B-AR and CXCR4:ACKR3 interactions in VSMC, however, remained constant. Our observations point towards TM2/4 of CXCR4 as possible contact sites for heteromerization and suggest that TM-derived peptide analogs permit selective targeting of CXCR4 heteromers. A molecular dynamics simulation of a receptor complex in which the CXCR4 homodimer interacts with α1A-AR via TM2 and with ACKR3 via TM4 is presented. Our findings further imply that CXCR4: α1A-AR heteromers are important for intrinsic α1-AR function in intact arteries and provide initial and unexpected insights into the regulation of CXCR4 heteromerization in VSMC.
KW - (C-X-C motif) receptor 7
KW - Adrenergic receptor
KW - Atypical chemokine receptor 3
KW - Blood pressure
KW - G protein-coupled receptor
KW - Receptor heteromer
KW - Structural modeling
KW - Vascular function
UR - http://www.scopus.com/inward/record.url?scp=85015592466&partnerID=8YFLogxK
U2 - 10.3390/ijms17060971
DO - 10.3390/ijms17060971
M3 - Article
C2 - 27331810
AN - SCOPUS:85015592466
SN - 1661-6596
VL - 17
JO - International journal of molecular sciences
JF - International journal of molecular sciences
IS - 6
M1 - 971
ER -