TY - JOUR
T1 - Salmonella administration induces a reduction of wheel-running activity via a TLR5-, but not a TLR4, dependent pathway in mice
AU - Matsumoto, Takashi
AU - Shiva, Daisuke
AU - Kawanishi, Noriaki
AU - Kato, Yasuko
AU - Woods, Jeffrey A.
AU - Yano, Hiromi
PY - 2008
Y1 - 2008
N2 - In general, systemic bacterial infections induce sickness behavior. In mice, lipopolysaccharide (LPS), a component of gram-negative bacteria, strongly reduces physical activity via toll-like receptor (TLR) 4. However, gram-negative bacteria, such as Salmonella, also express flagella containing flagellin (FG) which binds to TLR5 and induces pro-inflammatory cytokine production. It is unclear whether FG induces sickness behavior. To determine whether Salmonella administration regulates the reduction of voluntary physical activity in mice, male C3H/HeN (wild type) and C3H/HeJ (tlr4 gene mutated) mice were administered living Salmonella (live) and examined for wheel-running activity. The production of TNF-αin RAW 264 cells was measured by the ELISA assay under both live and heat-killed (HK) Salmonella conditions in vitro. Wheel-running activity in both C3H/HeJ and C3H/HeN mice after i.p. injection of live Salmonella (1×10 6 CFU/kg) was significantly lower than that in vehicle groups (p<0.01, respectively), although wheel-running activity in C3H/HeJ mice was not reduced after i.p. injection of HK Salmonella (1×10 6 CFU/kg). Furthermore, TNF-α production from RAW 264 cells with HK Salmonella treatment at the early phase was higher than that with live Salmonella treatment. Interestingly, gentamicin-treated (GMT) Salmonella, (which have bacterial flagella removed), did not induce reduction of wheel-running activity, although injection of the flagella-rich supernatant of GMT Salmonella significantly reduced it (p<0.01). Indeed, FG treatment also induced reduction of wheel-running activity in mice (p<0.01). Our findings suggest that the Salmonella-induced reduction of voluntary physical activity might be regulated by FG via TLR5, but not LPS via TLR4 in mice.
AB - In general, systemic bacterial infections induce sickness behavior. In mice, lipopolysaccharide (LPS), a component of gram-negative bacteria, strongly reduces physical activity via toll-like receptor (TLR) 4. However, gram-negative bacteria, such as Salmonella, also express flagella containing flagellin (FG) which binds to TLR5 and induces pro-inflammatory cytokine production. It is unclear whether FG induces sickness behavior. To determine whether Salmonella administration regulates the reduction of voluntary physical activity in mice, male C3H/HeN (wild type) and C3H/HeJ (tlr4 gene mutated) mice were administered living Salmonella (live) and examined for wheel-running activity. The production of TNF-αin RAW 264 cells was measured by the ELISA assay under both live and heat-killed (HK) Salmonella conditions in vitro. Wheel-running activity in both C3H/HeJ and C3H/HeN mice after i.p. injection of live Salmonella (1×10 6 CFU/kg) was significantly lower than that in vehicle groups (p<0.01, respectively), although wheel-running activity in C3H/HeJ mice was not reduced after i.p. injection of HK Salmonella (1×10 6 CFU/kg). Furthermore, TNF-α production from RAW 264 cells with HK Salmonella treatment at the early phase was higher than that with live Salmonella treatment. Interestingly, gentamicin-treated (GMT) Salmonella, (which have bacterial flagella removed), did not induce reduction of wheel-running activity, although injection of the flagella-rich supernatant of GMT Salmonella significantly reduced it (p<0.01). Indeed, FG treatment also induced reduction of wheel-running activity in mice (p<0.01). Our findings suggest that the Salmonella-induced reduction of voluntary physical activity might be regulated by FG via TLR5, but not LPS via TLR4 in mice.
KW - C3H/HeJ mouse
KW - Flagellin
KW - Lipopolysaccharide
KW - TLR5
KW - Toll-like receptors TLR4
KW - Voluntary physical activity
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M3 - Article
C2 - 19203083
AN - SCOPUS:62849090793
VL - 14
SP - 38
EP - 50
JO - Exercise Immunology Review
JF - Exercise Immunology Review
SN - 1077-5552
ER -