Downregulation of the Autism Spectrum Disorder Gene <i>Shank2</i> Decreases Bone Mass in Male Mice

Ahmad, Mubashir; Stirmlinger, Nadine; Jan, Irfana; Stifel, Ulrich; Lee, Sooyeon; Weingandt, Marcel; Kelp, Ulrike; Bockmann, Jürgen; Ignatius, Anita; Böckers, Tobias M.; Tuckermann, Jan

doi:10.1002/jbm4.10711

Cited by 2 publications

(5 citation statements)

References 75 publications

(117 reference statements)

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“…Osteoblast differentiation was performed as described. ( 33 ) Briefly, MSCs were seeded at a density of 25,000 cells/cm 2 . After 48 hours, the growth medium was replaced by osteogenic induction medium (100 μg/mL (+) sodium L‐ascorbate (Sigma‐Aldrich; Cat.…”

Section: Methodsmentioning

confidence: 99%

Wnt1 Boosts Fracture Healing by Enhancing Bone Formation in the Fracture Callus

Haffner‐Luntzer¹,

Ragipoglu²,

Ahmad³

et al. 2020

Journal of Bone and Mineral Research

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Despite considerable improvement in fracture care, 5%-10% of all fractures still heal poorly or result in nonunion formation. Therefore, there is an urgent need to identify new molecules that can be used to improve bone fracture healing. One activator of the Wnt-signaling cascade, Wnt1, has recently gained attention for its intense osteoanabolic effect on the intact skeleton. The aim of the present study was to investigate whether Wnt1 might be a promising molecule to accelerate fracture healing both in skeletally healthy and osteoporotic mice that display a diminished healing capacity. Transgenic mice for a temporary induction of Wnt1 specifically in osteoblasts (Wnt1-tg) were subjected to femur osteotomy. Non-ovariectomized and ovariectomized Wnt1-tg mice displayed significantly accelerated fracture healing based on a strong increase in bone formation in the fracture callus. Transcriptome profiling revealed that Hippo/yes1-associated transcriptional regulator (YAP)-signaling and bone morphogenetic protein (BMP) signaling pathways were highly enriched in the fracture callus of Wnt1-tg animals. Immunohistochemical staining confirmed increased activation of YAP1 and expression of BMP2 in osteoblasts in the fracture callus. Therefore, our data indicate that Wnt1 boosts bone formation during fracture healing via YAP/BMP signaling both under healthy and osteoporotic conditions. To further test a potential translational application of Wnt1, we applied recombinant Wnt1 embedded into a collagen gel during critical-size bone-defect repair. Mice treated with Wnt1 displayed increased bone regeneration compared to control mice accompanied by increased YAP1/BMP2 expression in the defect area. These findings are of high clinical relevance because they indicate that Wnt1 could be used as a new therapeutic agent to treat orthopedic complications in the clinic.

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Section: Methodsmentioning

confidence: 99%

Wnt1 Boosts Fracture Healing by Enhancing Bone Formation in the Fracture Callus

Haffner‐Luntzer¹,

Ragipoglu²,

Ahmad³

et al. 2020

Journal of Bone and Mineral Research

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“…For qualitative Alp staining, we followed a previously established protocol 45 . Briefly, primary osteoblasts were washed with PBS and fixed with 4% paraformaldehyde (10 min, RT).…”

Section: Methodsmentioning

confidence: 99%

“…For quantitative Alp staining, a previously described colorimetric method was employed 45 . In brief, cells were seeded at a confluency of 20 000 cells/cm 2 in a 24‐well plate and differentiated with osteogenic induction medium.…”

Section: Methodsmentioning

confidence: 99%

“…For quantitative Alp staining, a previously described colorimetric method was employed. 45 In brief, cells were seeded at a confluency of 20 000 cells/cm 2 in a 24-well plate and differentiated with osteogenic induction medium. Alp activity was determined using the Amplite colorimetric alkaline phosphatase assay kit (Biomol GmbH, Hamburg, Germany) following the manufacturer's instructions.…”

Section: Qualitative and Quantitative Alkaline Phosphatase (Alp) Stai...mentioning

confidence: 99%

“…For qualitative Alp staining, we followed a previously established protocol. 45 Briefly, primary osteoblasts were washed with PBS and fixed with 4% paraformaldehyde (10 min, RT). Alp staining solution (Sigma-Aldrich, St. Louis, MO, USA) was added according to the manufacturer's instructions, and the 24-well plates were incubated in the dark (1 h, RT).…”

Section: Qualitative and Quantitative Alkaline Phosphatase (Alp) Stai...mentioning

confidence: 99%

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Mechanical induction of osteoanabolic Wnt1 promotes osteoblast differentiation via Plat

Ahmad,

Haffner‐Luntzer,

Schoppa

et al. 2024

The FASEB Journal

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Physical activity‐induced mechanical stimuli play a crucial role in preserving bone mass and structure by promoting bone formation. While the Wnt pathway is pivotal for mediating the osteoblast response to loading, the exact mechanisms are not fully understood. Here, we found that mechanical stimulation induces osteoblastic Wnt1 expression, resulting in an upregulation of key osteogenic marker genes, including Runx2 and Sp7, while Wnt1 knockdown using siRNA prevented these effects. RNAseq analysis identified Plat as a major target through which Wnt1 exerts its osteogenic influence. This was corroborated by Plat depletion using siRNA, confirming its positive role in osteogenic differentiation. Moreover, we demonstrated that mechanical stimulation enhances Plat expression, which, in turn leads to increased expression of osteogenic markers like Runx2 and Sp7. Notably, Plat depletion by siRNA prevented this effect. We have established that Wnt1 regulates Plat expression by activating β‐Catenin. Silencing Wnt1 impairs mechanically induced β‐Catenin activation, subsequently reducing Plat expression. Furthermore, our findings showed that Wnt1 is essential for osteoblasts to respond to mechanical stimulation and induce Runx2 and Sp7 expression, in part through the Wnt1/β‐Catenin/Plat signaling pathway. Additionally, we observed significantly reduced Wnt1 and Plat expression in bones from ovariectomy (OVX)‐induced and age‐related osteoporotic mouse models compared with non‐OVX and young mice, respectively. Overall, our data suggested that Wnt1 and Plat play significant roles in mechanically induced osteogenesis. Their decreased expression in bones from OVX and aged mice highlights their potential involvement in post‐menopausal and age‐related osteoporosis, respectively.

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Downregulation of the Autism Spectrum Disorder Gene Shank2 Decreases Bone Mass in Male Mice

Cited by 2 publications

References 75 publications

Wnt1 Boosts Fracture Healing by Enhancing Bone Formation in the Fracture Callus

Wnt1 Boosts Fracture Healing by Enhancing Bone Formation in the Fracture Callus

Mechanical induction of osteoanabolic Wnt1 promotes osteoblast differentiation via Plat

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