title: Chondrocyte clocks make cartilage time-sensitive material.
abstract: Circadian rhythms mediated by both central and tissue-specific peripheral clocks allow for the synchronization of biological processes with diurnal cycles such as activity and rest. Disruption of these rhythms can be caused by altered sleep-awake patterns or by pathological conditions and can initiate or exacerbate human disease through mechanisms that are only partially understood. In this issue, Dudek et al. identify a chondrocyte-autonomous cartilage clock and demonstrate that expression of an important circadian pacemaker, BMAL1, decreases during osteoarthritis progression. They show that chondrocyte-specific deletion of BMAL1 leads to cartilage degradation and disruption of key pathways, shifting cartilage homeostasis toward a catabolic state. These findings provide insight into the interplay between circadian rhythm and cartilage in osteoarthritis.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Doody
authors.forename: Nunzio
authors.initials: N
authors.lastname: Bottini
mesh_terms: D056930:ARNTL Transcription Factors / Q000502:physiology*; D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism*; D019902:Chondrocytes / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D010003:Osteoarthritis / Q000209:etiology*
chemical_list: D056930:ARNTL Transcription Factors