Circadian disruption by shifting the light-dark cycle negatively affects bone health in mice

TY - JOUR

T1 - Circadian disruption by shifting the light-dark cycle negatively affects bone health in mice

AU - Schilperoort, Maaike

AU - Bravenboer, Nathalie

AU - Lim, Joann

AU - Mletzko, Kathrin

AU - Busse, Björn

AU - van Ruijven, Leo

AU - Kroon, Jan

AU - Rensen, Patrick C N

AU - Kooijman, Sander

AU - Winter, Elizabeth M

PY - 2020/1

Y1 - 2020/1

N2 - The past decade, it has become evident that circadian rhythms within metabolically active tissues are very important for physical health. However, although shift work has also been associated with an increased risk of fractures, circadian rhythmicity has not yet been extensively studied in bone. Here, we investigated which genes are rhythmically expressed in bone, and whether circadian disruption by shifts in light-dark cycle affects bone turnover and structure in mice. Our results demonstrate diurnal expression patterns of clock genes (Rev-erbα, Bmal1, Per1, Per2, Cry1, Clock), as well as genes involved in osteoclastogenesis, osteoclast proliferation and function (Rankl, Opg, Ctsk), and osteocyte function (c-Fos) in bone. Weekly alternating light-dark cycles disrupted rhythmic clock gene expression in bone and caused a reduction in plasma levels of procollagen type 1 amino-terminal propeptide (P1NP) and tartrate-resistant acidic phosphatase (TRAP), suggestive of a reduced bone turnover. These effects coincided with an altered trabecular bone structure and increased cortical mineralization after 15 weeks of light-dark cycles, which may negatively affect bone strength in the long term. Collectively, these results show that a physiological circadian rhythm is important to maintain bone health, which stresses the importance of further investigating the association between shift work and skeletal disorders.

AB - The past decade, it has become evident that circadian rhythms within metabolically active tissues are very important for physical health. However, although shift work has also been associated with an increased risk of fractures, circadian rhythmicity has not yet been extensively studied in bone. Here, we investigated which genes are rhythmically expressed in bone, and whether circadian disruption by shifts in light-dark cycle affects bone turnover and structure in mice. Our results demonstrate diurnal expression patterns of clock genes (Rev-erbα, Bmal1, Per1, Per2, Cry1, Clock), as well as genes involved in osteoclastogenesis, osteoclast proliferation and function (Rankl, Opg, Ctsk), and osteocyte function (c-Fos) in bone. Weekly alternating light-dark cycles disrupted rhythmic clock gene expression in bone and caused a reduction in plasma levels of procollagen type 1 amino-terminal propeptide (P1NP) and tartrate-resistant acidic phosphatase (TRAP), suggestive of a reduced bone turnover. These effects coincided with an altered trabecular bone structure and increased cortical mineralization after 15 weeks of light-dark cycles, which may negatively affect bone strength in the long term. Collectively, these results show that a physiological circadian rhythm is important to maintain bone health, which stresses the importance of further investigating the association between shift work and skeletal disorders.

U2 - 10.1096/fj.201901929R

DO - 10.1096/fj.201901929R

M3 - SCORING: Journal article

C2 - 31914701

VL - 34

SP - 1052

EP - 1064

JO - FASEB J

JF - FASEB J

SN - 0892-6638

IS - 1

ER -