TY - JOUR
T1 - Exercise-evoked intramuscular neutrophil-endothelial interactions support muscle performance and GLUT4 translocation
T2 - a mouse gnawing model study
AU - Chaweewannakorn, Chayanit
AU - Nyasha, Mazvita R.
AU - Chen, Weijian
AU - Sekiai, Shigenori
AU - Tsuchiya, Masahiro
AU - Hagiwara, Yoshihiro
AU - Bouzakri, Karim
AU - Sasaki, Keiichi
AU - Kanzaki, Makoto
N1 - Funding Information:
This work was supported in part by grants from the Japan Society for the Promotion of Science (no. 16K11580 to MT and nos 17H02076 and 18K19722 to MK) and the Japan Agency for Medical Research and Development (no. 18 058 831 to MK). This study was also partially supported by a research grant from the Uehara Memorial Foundation (to MK).
Funding Information:
This work was supported in part by grants from the Japan Society for the Promotion of Science (no. 16K11580 to MT and nos 17H02076 and 18K19722 to MK) and the Japan Agency for Medical Research and Development (no. 18?058?831 to MK). This study was also partially supported by a research grant from the Uehara Memorial Foundation (to MK). We thank Natsumi Emoto for technical assistance. We thank Drs Edna Hardeman (University of New South Wales) and Hiroshi Shibata (Gunma University) for providing the human??-actin promoter plasmid and the anti-GLUT4 antibody, respectively.
Publisher Copyright:
© 2019 The Authors. The Journal of Physiology © 2019 The Physiological Society
PY - 2020/1/1
Y1 - 2020/1/1
N2 - Key points: Fractalkine receptor antagonist inhibited neutrophil recruitment to masseter muscles and exacerbated fatigability during masticatory activity. Fractalkine-mediated neutrophil recruitment is required for both upregulation of myokines (CXCL1, interleukin-6) and enhanced GLUT4 translocation in response to masticatory activity. Fractalkine and intercellular adhesion molecule-1 expression in endothelial cells increased in response to masticatory activity. In vitro experiments demonstrated that contracting myotubes lack the ability to upregulate fractalkine but revealed that endothelial fractalkine upregulation is induced using a conditioned medium of contracting myotubes. Abstract: Physical exercise stimulates neutrophil recruitment within working skeletal muscle, although its underlying mechanisms remain ill-defined. By employing a masticatory behaviour (gnawing) model, we demonstrate the importance of intramuscular paracrine and autocrine systems that are triggered by muscle contractile activity and reliant upon fractalkine/CX3CL1-mediated signals. These signals were revealed to be required for achieving proper GLUT4 translocation and glucose uptake to meet the glucose demands for fatigue alleviation. Specifically, fractalkine expression and neutrophil recruitment both increased in the masseter muscle tissues upon masticatory activity. Importantly, a fractalkine antagonist inhibited neutrophil accumulation and exacerbated fatigability during masticatory activity. We found that fractalkine-dependent neutrophil recruitment is required for both upregulation of myokines (i.e. CXCL1 and interleukin-6) and enhanced GLUT4 translocation in response to gnawing activity. Immunofluorescence analysis of masseter muscles demonstrated that fractalkine and intercellular adhesion molecule-1 expression are both upregulated in endothelial cells but not in myofibres. The in vitro exercise model further revealed that contractile activity failed to stimulate fractalkine upregulation in myotubes, implying that fractalkine is not a myokine (myofibre-derived factor). Nevertheless, endothelial fractalkine expression was markedly stimulated by a conditioned medium from the contracting myotubes. Moreover, intercellular adhesion molecule-1, a key adhesion molecule for neutrophils, was upregulated in endothelial cells by fractalkine. Taken together, our findings strongly suggest that endothelial fractalkine serves as a key factor for organizing a physiologically beneficial intramuscular microenvironment by recruiting neutrophils in response to relatively mild exercise (i.e. masticatory muscle activity).
AB - Key points: Fractalkine receptor antagonist inhibited neutrophil recruitment to masseter muscles and exacerbated fatigability during masticatory activity. Fractalkine-mediated neutrophil recruitment is required for both upregulation of myokines (CXCL1, interleukin-6) and enhanced GLUT4 translocation in response to masticatory activity. Fractalkine and intercellular adhesion molecule-1 expression in endothelial cells increased in response to masticatory activity. In vitro experiments demonstrated that contracting myotubes lack the ability to upregulate fractalkine but revealed that endothelial fractalkine upregulation is induced using a conditioned medium of contracting myotubes. Abstract: Physical exercise stimulates neutrophil recruitment within working skeletal muscle, although its underlying mechanisms remain ill-defined. By employing a masticatory behaviour (gnawing) model, we demonstrate the importance of intramuscular paracrine and autocrine systems that are triggered by muscle contractile activity and reliant upon fractalkine/CX3CL1-mediated signals. These signals were revealed to be required for achieving proper GLUT4 translocation and glucose uptake to meet the glucose demands for fatigue alleviation. Specifically, fractalkine expression and neutrophil recruitment both increased in the masseter muscle tissues upon masticatory activity. Importantly, a fractalkine antagonist inhibited neutrophil accumulation and exacerbated fatigability during masticatory activity. We found that fractalkine-dependent neutrophil recruitment is required for both upregulation of myokines (i.e. CXCL1 and interleukin-6) and enhanced GLUT4 translocation in response to gnawing activity. Immunofluorescence analysis of masseter muscles demonstrated that fractalkine and intercellular adhesion molecule-1 expression are both upregulated in endothelial cells but not in myofibres. The in vitro exercise model further revealed that contractile activity failed to stimulate fractalkine upregulation in myotubes, implying that fractalkine is not a myokine (myofibre-derived factor). Nevertheless, endothelial fractalkine expression was markedly stimulated by a conditioned medium from the contracting myotubes. Moreover, intercellular adhesion molecule-1, a key adhesion molecule for neutrophils, was upregulated in endothelial cells by fractalkine. Taken together, our findings strongly suggest that endothelial fractalkine serves as a key factor for organizing a physiologically beneficial intramuscular microenvironment by recruiting neutrophils in response to relatively mild exercise (i.e. masticatory muscle activity).
KW - GLUT4
KW - endothelial cell
KW - exercise
KW - fatigue alleviation
KW - fractalkine
KW - immunometabolic niche
KW - myokine
KW - neutrophil
UR - http://www.scopus.com/inward/record.url?scp=85076352845&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85076352845&partnerID=8YFLogxK
U2 - 10.1113/JP278564
DO - 10.1113/JP278564
M3 - Article
C2 - 31721209
AN - SCOPUS:85076352845
VL - 598
SP - 101
EP - 122
JO - Journal of Physiology
JF - Journal of Physiology
SN - 0022-3751
IS - 1
ER -