scholarly journals Mice lacking DKK1 in T cells exhibit high bone mass and are protected from estrogen deficiency-induced bone loss

iScience ◽  
2021 ◽  
pp. 102224
Author(s):  
Juliane Lehmann ◽  
Sylvia Thiele ◽  
Ulrike Baschant ◽  
Tilman D. Rachner ◽  
Christof Niehrs ◽  
...  
2019 ◽  
Vol 116 (52) ◽  
pp. 26808-26815 ◽  
Author(s):  
Li Sun ◽  
Daria Lizneva ◽  
Yaoting Ji ◽  
Graziana Colaianni ◽  
Elina Hadelia ◽  
...  

The primitive neurohypophyseal nonapeptide oxytocin (OXT) has established functions in parturition, lactation, appetite, and social behavior. We have shown that OXT has direct actions on the mammalian skeleton, stimulating bone formation by osteoblasts and modulating the genesis and function of bone-resorbing osteoclasts. We deleted OXT receptors (OXTRs) selectively in osteoblasts and osteoclasts usingCol2.3CreandAcp5Cremice, respectively. Both male and femaleCol2.3Cre+:Oxtrfl/flmice recapitulate the low-bone mass phenotype ofOxtr+/−mice, suggesting that OXT has a prominent osteoblastic action in vivo. Furthermore, abolishment of the anabolic effect of estrogen inCol2.3Cre+:Oxtrfl/flmice suggests that osteoblastic OXTRs are necessary for estrogen action. In addition, the high bone mass inAcp5Cre+:Oxtrfl/flmice indicates a prominent action of OXT in stimulating osteoclastogenesis. In contrast, we found that in pregnant and lactatingCol2.3Cre+:Oxtrfl/flmice, elevated OXT inhibits bone resorption and rescues the bone loss otherwise noted during pregnancy and lactation. However, OXT does not contribute to ovariectomy-induced bone loss. Finally, we show that OXT acts directly on OXTRs on adipocytes to suppress the white-to-beige transition gene program. Despite this direct antibeiging action, injected OXT reduces total body fat, likely through an action on OXT-ergic neurons. Consistent with an antiobesity action of OXT,Oxt−/−andOxtr−/−mice display increased total body fat. Overall, the actions of OXT on bone mass and body composition provide the framework for future therapies for osteoporosis and obesity.


2014 ◽  
Vol 29 (4) ◽  
pp. 820-829 ◽  
Author(s):  
Tujun Weng ◽  
Yangli Xie ◽  
Junlan Huang ◽  
Fengtao Luo ◽  
Lingxian Yi ◽  
...  

Bone ◽  
2016 ◽  
Vol 87 ◽  
pp. 114-119 ◽  
Author(s):  
M. Raygorodskaya ◽  
Y. Gabet ◽  
C. Shochat ◽  
E. Kobyliansky ◽  
A. Torchinsky ◽  
...  

2021 ◽  
Vol 19 (2) ◽  
pp. 115-122
Author(s):  
A. Hartley ◽  
C. L. Gregson ◽  
L. Paternoster ◽  
J. H. Tobias

Abstract Purpose of Review This paper reviews how bone genetics has contributed to our understanding of the pathogenesis of osteoarthritis. As well as identifying specific genetic mechanisms involved in osteoporosis which also contribute to osteoarthritis, we review whether bone mineral density (BMD) plays a causal role in OA development. Recent Findings We examined whether those genetically predisposed to elevated BMD are at increased risk of developing OA, using our high bone mass (HBM) cohort. HBM individuals were found to have a greater prevalence of OA compared with family controls and greater development of radiographic features of OA over 8 years, with predominantly osteophytic OA. Initial Mendelian randomisation analysis provided additional support for a causal effect of increased BMD on increased OA risk. In contrast, more recent investigation estimates this relationship to be bi-directional. However, both these findings could be explained instead by shared biological pathways. Summary Pathways which contribute to BMD appear to play an important role in OA development, likely reflecting shared common mechanisms as opposed to a causal effect of raised BMD on OA. Studies in HBM individuals suggest this reflects an important role of mechanisms involved in bone formation in OA development; however further work is required to establish whether the same applies to more common forms of OA within the general population.


2021 ◽  
Vol 23 (1) ◽  
Author(s):  
April Hartley ◽  
Sarah A. Hardcastle ◽  
Monika Frysz ◽  
Jon Parkinson ◽  
Lavinia Paternoster ◽  
...  

Abstract Background Individuals with high bone mass (HBM) have a greater odds of prevalent radiographic hip osteoarthritis (OA), reflecting an association with bone-forming OA sub-phenotypes (e.g. osteophytosis, subchondral sclerosis). As the role of bone mineral density (BMD) in hip OA progression is unclear, we aimed to determine if individuals with HBM have increased incidence and/or progression of bone-forming OA sub-phenotypes. Methods We analysed an adult cohort with and without HBM (L1 and/or total hip BMD Z-score > + 3.2) with pelvic radiographs collected at baseline and 8-year follow-up. Sub-phenotypes were graded using the OARSI atlas. Superior/inferior acetabular/femoral osteophyte and medial/superior joint space narrowing (JSN) grades were summed and Δosteophyte and ΔJSN derived. Pain and functional limitations were quantified using the WOMAC questionnaire. Associations between HBM status and change in OA sub-phenotypes were determined using multivariable linear/logistic regression, adjusting for age, sex, height, total body fat mass, follow-up time and baseline sub-phenotype grade. Generalised estimating equations accounted for individual-level clustering. Results Of 136 individuals, 62% had HBM at baseline, 72% were female and mean (SD) age was 59 (10) years. HBM was positively associated with both Δosteophytes and ΔJSN (adjusted mean grade differences between individuals with and without HBM βosteophyte = 0.30 [0.01, 0.58], p = 0.019 and βJSN = 0.10 [0.01, 0.18], p = 0.019). Incident subchondral sclerosis was rare. HBM individuals had higher WOMAC hip functional limitation scores (β = 8.3 [0.7, 15.98], p = 0.032). Conclusions HBM is associated with the worsening of hip osteophytes and JSN over an average of 8 years, as well as increased hip pain and functional limitation.


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