Calcitonin Receptor Signaling Inhibits Muscle Stem Cells from Escaping the Quiescent State and the Niche
CELL REPORTS
Authors: Yamaguchi, Masahiko; Watanabe, Yoko; Ohtani, Takuji; Uezumi, Akiyoshi; Mikami, Norihisa; Nakamura, Miki; Sato, Takahiko; Ikawa, Masahito; Hoshino, Mikio; Tsuchida, Kunihiro; Miyagoe-Suzuki, Yuko; Tsujikawa, Kazutake; Takeda, Shin'ichi; Yamamoto, Hiroshi; Fukada, So-ichiro
Abstract
Calcitonin receptor (Calcr) is expressed in adult muscle stem cells (muscle satellite cells [MuSCs]). To elucidate the role of Calcr, we conditionally depleted Calcr from adult MuSCs and found that impaired regeneration after muscle injury correlated with the decreased number of MuSCs in Calcr-conditional knockout (cKO) mice. Calcr signaling maintained MuSC dormancy via the cAMP-PKA pathway but had no impact on myogenic differentiation of MuSCs in an undifferentiated state. The abnormal quiescent state in Calcr-cKO mice resulted in a reduction of the MuSC pool by apoptosis. Furthermore, MuSCs were found outside their niche in Calcr-cKO mice, demonstrating cell relocation. This emergence from the sublaminar niche was prevented by the CalcrcAMP-PKA and Calcr-cAMP-Epac pathways downstream of Calcr. Altogether, the findings demonstrated that Calcr exerts its effect specifically by keeping MuSCs in a quiescent state and in their location, maintaining the MuSC pool.
Genetic overlap between birthweight and adult cardiometabolic diseases has implications for genomic medicine
SCIENTIFIC REPORTS
Authors: Tekola-Ayele, Fasil; Lee, Anthony; Workalemahu, Tsegaselassie; Zhang, Wei; Shrestha, Deepika; Amare, Azmeraw T.; Ouidir, Marion
Abstract
Before implementing therapeutic genomic interventions for optimizing health in early life, comprehensive understanding of their effect on several traits across the life course is warranted. Abnorml birthweight is associated with cardiometabolic disease risk in adulthood; however, the extent of genetic pleiotropy in the association has not been comprehensively investigated. We tested for pleiotropy and enrichment of functional loci between birthweight and 15 cardiometabolic disease traits (CMD). We found significantly abundant genetic pleiotropy (P < 3.3 x 10(-3)) and enrichment of functional annotations (P < 3.3 x 10(-3)) in loci influencing both birthweight and CMD. We did not observe consistent effect directions of pleiotropic loci on the traits. A total of 67 genetic loci, of which 65 loci have been reported in previous genome-wide association studies, were associated with both birthweight and CMD at a false discovery rate of 5%. Two novel loci were associated with birthweight and adult coronary artery disease (rs2870463 in CTRB1) and with birthweight and adult waist circumference (rs12704673 in CALCR). Both loci are known to have regulatory effects on expression of nearby genes. In all, our findings revealed pervasive genetic pleiotropy in early growth and adulthood cardiometabolic diseases, implying the need for caution when considering genetic loci as therapeutic targets.