3024 Osteocyte-derived CXCL12 is Essential for Load-Induced Bone Formation in Adult Mice

OBJECTIVES/SPECIFIC AIMS: Our aim is to test whether osteocyte-specific CXCL12 expression is critical to exercise-driven bone formation. METHODS/STUDY POPULATION: All procedures were approved by the NEW YORK UNIVERSITY Institutional Animal Care and Use Committee. We generated male and female mice in which CXCL12 was deleted from OCYs (CXCL12ΔOCY) by crossing CXCL12 floxed mice and 10kb DMP1-Cre transgenic mice (gifts from Drs. Geoffrey Gurtner and Lynda Bonewald, respectively). The 10kb DMP1-Cre has been shown to be robustly expressed in odontoblasts and OCYs, with little to no activity in cells from non-mineralized tissues (Lu+ J Dent Res 2007). Growing male and female mice (n=3-8/group) were given fluorochrome labels every two weeks between 4-16 weeks of age, to monitor the role of CXCL12 during development. A second group, of adult 16-week-old mice (n=5/group), were subjected to tibial axial cyclic loading (1200µɛ, 2Hz, 120cycles, 3days/wk for 2 wks) (Liu+ Bone 2018). Basal and load-induced periosteal (Ps) and endosteal (Es) mineralizing surface (MS/BS, %), mineral apposition (MAR, µm/day) and bone formation rates (BFR/BS, µm3/µm2/year) were calculated (Dempster+ JBMR.2013) at mid-length. RESULTS/ANTICIPATED RESULTS: No significant differences were detected in basal bone formation during development. However, relative load-induced Ps MAR (rMAR) was reduced by 50% in female (p=0.02) and 75% in male (p=0.002) CXCL12ΔOCY mice; and similarly, Ps rBFR/BS was reduced by 50% in female (p=0.01) and 70% in male (p=0.001) CXCL12ΔOCY mice (Figure 1). Es bone formation was not affected by CXCL12 deletion. DISCUSSION/SIGNIFICANCE OF IMPACT: In summary, osteocyte-specific CXCL12 expression plays a critical role in exercise-driven periosteal new bone formation, suggesting that CXCL12 signaling may positively regulate osteogenic differentiation and/or mature osteoblast function. Further underlying mechanisms are currently being explored. Thus, osteocyte-specific CXCL12 signaling may be a promising target to enhance load-induced bone formation in patients with compromised ability to form new bone.

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The melanocortin-3 receptor is a pharmacological target for the regulation of anorexia

Science Translational Medicine ◽

10.1126/scitranslmed.abd6434 ◽

2021 ◽

Vol 13 (590) ◽

pp. eabd6434

Author(s):

Patrick Sweeney ◽

Michelle N. Bedenbaugh ◽

Jose Maldonado ◽

Pauline Pan ◽

Katelyn Fowler ◽

...

Keyword(s):

Sexual Dimorphism ◽

Feeding Behavior ◽

Critical Role ◽

Brain Regions ◽

Sexually Dimorphic ◽

Male And Female ◽

Female Mice ◽

Bidirectional Regulation ◽

Fear And Anxiety ◽

Agouti Related Protein

Ablation of hypothalamic AgRP (Agouti-related protein) neurons is known to lead to fatal anorexia, whereas their activation stimulates voracious feeding and suppresses other motivational states including fear and anxiety. Despite the critical role of AgRP neurons in bidirectionally controlling feeding, there are currently no therapeutics available specifically targeting this circuitry. The melanocortin-3 receptor (MC3R) is expressed in multiple brain regions and exhibits sexual dimorphism of expression in some of those regions in both mice and humans. MC3R deletion produced multiple forms of sexually dimorphic anorexia that resembled aspects of human anorexia nervosa. However, there was no sexual dimorphism in the expression of MC3R in AgRP neurons, 97% of which expressed MC3R. Chemogenetic manipulation of arcuate MC3R neurons and pharmacologic manipulation of MC3R each exerted potent bidirectional regulation over feeding behavior in male and female mice, whereas global ablation of MC3R-expressing cells produced fatal anorexia. Pharmacological effects of MC3R compounds on feeding were dependent on intact AgRP circuitry in the mice. Thus, the dominant effect of MC3R appears to be the regulation of the AgRP circuitry in both male and female mice, with sexually dimorphic sites playing specialized and subordinate roles in feeding behavior. Therefore, MC3R is a potential therapeutic target for disorders characterized by anorexia, as well as a potential target for weight loss therapeutics.

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CaMKK2-Mediated Effects on Mechanically Induced Bone Formation in Male and Female Mice

Proceedings of IMPRS ◽

10.18060/24525 ◽

2020 ◽

Vol 3 ◽

Author(s):

Margaret Bello ◽

Adam Warrick ◽

Brett Mattingly ◽

Justin Williams ◽

Uma Sankar

Keyword(s):

Protein Kinase ◽

Bone Density ◽

Bone Formation ◽

Fracture Healing ◽

Enzyme Linked Immunosorbent Assay ◽

Alizarin Red ◽

Bone Formation Rate ◽

Male And Female ◽

Female Mice ◽

Initial Loading

Background and Hypothesis: Ca2+/calmo-dulin-dependent protein kinase kinase 2 (CaMKK2) is a serine-threonine protein kinase that plays a significant role in both anabolic and catabolic pathways of bone remodeling. Mechanical loading of bone translates an external force into both biochemical and structural changes. It has been shown that deletion or inhibition of CaMKK2 results in increased bone density in male and female mice. We hypothesize that the lack of CaMKK2 in bone cells will result in loading-induced bone mass accrual with no difference between male and female mice. Experimental Design or Project Methods: The right tibia of anesthetized 16-week-old wild-type (WT) and CaMKK2 knockout (KO) mice were loaded at 2 Hz for 220 cycles and with peak forces specific to both sex and genotype. Loading was accomplished using an electro actuator (Bose ElectroForce 3200; EnduraTEC, Minnetonka, MN, USA). This was repeated 3, 5, 8 and 10 days after initial loading. The non-loaded left tibia served as an internal control. Calcein and alizarin red were administered intraperitoneally on days 9 and 16, respectively to metabolically label newly formed bone. Nineteen days after initial loading, mice were sacrificed. Blood and long bones of the lower limbs were collected for analysis. Results: Using microcomputer tomography; dynamic histomorphometry; histology, immunohistochemistry, enzyme-linked immunosorbent assay and real-time reverse transcription-polymerase chain reaction, we will assess bone volume, bone formation rate, and underlying mechanisms at the cellular and molecular level. These data are forthcoming. Conclusion and Potential Impact: With expanded knowledge on how bone growth is augmented, clinical outcomes related to osteoporosis and fracture healing, for example, may be improved. This may be accomplished through novel therapy related to these pathways that increases bone density or decreases fracture healing time.

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Bone microstructural defects and osteopenia in hemizygous βIVSII-654knockin thalassemic mice: sex-dependent changes in bone density and osteoclast function

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00329.2015 ◽

2015 ◽

Vol 309 (11) ◽

pp. E936-E948 ◽

Cited By ~ 8

Author(s):

Kanogwun Thongchote ◽

Saovaros Svasti ◽

Jarinthorn Teerapornpuntakit ◽

Panan Suntornsaratoon ◽

Nateetip Krishnamra ◽

...

Keyword(s):

Bone Formation ◽

Bone Histomorphometry ◽

Formation Rate ◽

Computer Assisted ◽

Mineral Density ◽

Bone Formation Rate ◽

Male And Female ◽

Female Mice ◽

Growing Period ◽

Microstructural Defects

β-Thalassemia, a hereditary anemic disorder, is often associated with skeletal complications that can be found in both males and females. The present study aimed to investigate the age- and sex-dependent changes in bone mineral density (BMD) and trabecular microstructure in βIVSII-654knockin thalassemic mice. Dual-energy X-ray absorptiometry and computer-assisted bone histomorphometry were employed to investigate temporal changes in BMD and histomorphometric parameters in male and female mice of a βIVSII-654knockin mouse model of human β-thalassemia, in which impaired splicing of β-globin transcript was caused by hemizygous C→T mutation at nucleotide 654 of intron 2. Young, growing βIVSII-654mice (1 mo old) manifested shorter bone length and lower BMD than their wild-type littermates, indicating possible growth retardation and osteopenia, the latter of which persisted until 8 mo of age (adult mice). Interestingly, two-way analysis of variance suggested an interaction between sex and βIVSII-654genotype, i.e., more severe osteopenia in adult female mice. Bone histomorphometry further suggested that low trabecular bone volume in male βIVSII-654mice, particularly during a growing period (1–2 mo), was primarily due to suppression of bone formation, whereas both a low bone formation rate and a marked increase in osteoclast surface were observed in female βIVSII-654mice. In conclusion, osteopenia and trabecular microstructural defects were present in both male and female βIVSII-654knockin thalassemic mice, but the severity, disease progression, and cellular mechanism differed between the sexes.

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Lead in the Water Supply Alters Swimming-Maze Behavior in Adult Mice

Perceptual and Motor Skills ◽

10.2466/pms.1982.55.2.507 ◽

1982 ◽

Vol 55 (2) ◽

pp. 507-512 ◽

Cited By ~ 1

Author(s):

K. Mc Lean ◽

G. H. Parker ◽

M. A. Persinger

Keyword(s):

Drinking Water ◽

Water Supply ◽

Tap Water ◽

Test Block ◽

Food Regime ◽

Male And Female ◽

Female Mice ◽

Adult Mice ◽

Body Weights ◽

Ad Libitum

After about two weeks of exposure to either 20 ppm or approximately 2000 ppm of lead in the drinking water or tap water only and under an ad libitum or restricted food regime, albino male and female mice ( N = 48) were tested for three consecutive days (3 blocks of 3 trials per day) in a swimming maze. Body weights were not altered by lead treatments significantly. The mice treated with the lead displayed longer escape latencies and more errors than the controls on tap water. Statistically significant interactions of lead treatment by test day by test block were also apparent.

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Membrane progesterone receptor-β, but not -α, in dorsal brain stem establishes sex-specific chemoreflex responses and reduces apnea frequency in adult mice

Journal of Applied Physiology ◽

10.1152/japplphysiol.00397.2016 ◽

2016 ◽

Vol 121 (3) ◽

pp. 781-791 ◽

Cited By ~ 10

Author(s):

Ryma Boukari ◽

Orlane Rossignol ◽

Cécile Baldy ◽

François Marcouiller ◽

Aida Bairam ◽

...

Keyword(s):

Brain Stem ◽

Progesterone Receptors ◽

Respiratory Control ◽

Staining Intensity ◽

Whole Body ◽

Male And Female ◽

Female Mice ◽

Adult Mice ◽

Specific Effects ◽

Membrane Progesterone Receptor

We tested the hypothesis that membrane progesterone receptors (mPR) contribute to respiratory control in adult male and female mice. Mice were implanted with osmotic minipumps for continuous infusion of small interfering RNA (siRNA) directed against mPRα, mPRβ, or a control solution in the fourth ventricle (to target brain stem respiratory areas) for 14 days. We then performed respiratory and metabolic recordings by whole body plethysmography at rest and in response to hypoxia (12% O2) or hypercapnia (5% CO2, 5 min each). For each treatment, we have verified with immunohistochemistry that the staining intensity of mPRα or mPRβ in the brain stem is decreased. At rest, the siRNA against mPRα and mPRβ increased respiratory frequency in males only. The siRNA against mPRβ almost tripled the frequency of apneas in male and in female mice, while the siRNA against mPRα had no effect. Regarding respiratory chemoreflex, the siRNA against mPRβ suppressed the response to hypoxia in male and female mice and reduced by ∼50% the response to hypercapnia, while the siRNA against mPRα had more limited effects. Interestingly, control females had higher ventilatory response to hypoxia and hypercapnia than males, and these sex-specific effects were suppressed by the siRNA against mPRβ, whereas they were still present after treatment with the siRNA against mPRα. We conclude that mPRβ reduces apnea frequency in male and female mice and establishes sex-specific ventilatory chemoreflex.

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Estrogen responsiveness of bone formation in vitro and altered bone phenotype in aged estrogen receptor-α-deficient male and female mice

Acta Endocrinologica ◽

10.1530/eje.1.01832 ◽

2005 ◽

Vol 152 (2) ◽

pp. 301-314 ◽

Cited By ~ 38

Author(s):

Vilhelmiina Parikka ◽

ZhiQi Peng ◽

Teuvo Hentunen ◽

Juha Risteli ◽

Teresa Elo ◽

...

Keyword(s):

Bone Marrow ◽

Bone Formation ◽

Bone Marrow Cells ◽

Type I ◽

Wild Type ◽

Male And Female ◽

Female Mice ◽

Bone Phenotype ◽

Marrow Cells

Objective: Although the beneficial effects of estrogen on bone are well known, the roles of estrogen receptors (ERs) in mediating these effects are not fully understood. Methods: To study the effects of long-term ERα deficiency, bone phenotype was studied in aged ERα knockout (ERKO) mice. In addition, ERKO osteoclasts and osteoblasts were cultured in vitro. Design and results: Histomorphometric analysis showed that the trabecular bone volume and thickness were significantly increased and the rate of bone formation enhanced in both male and female ERKO mice in comparison to the wild-type animals. In ERKO males, however, the bones were thinner and their maximal bending strengths decreased. Consistent with previous reports, the bones of knockout mice, especially of female mice, were shorter than those of wild-type mice. In addition, the growth plates were totally absent in the tibiae of aged ERKO females, whereas the growth plate cartilages were detectable in wild-type females as well as in all the males. Analysis of cultured bone marrow cells from 10- to 12-week-old mice demonstrated that 17β-estradiol could stimulate osteoblastic differentiation of bone marrow cells derived from ERKO mice relatively to the same extent as those derived from wild-type mice. This was demonstrated by increases in synthesis of type I collagen, activity of alkaline phosphatase and accumulation of calcium in cultures. Total protein content was, however, reduced in ERKO osteoblast cultures. Conclusions: These results show altered bone phenotype in ERKO mice and demonstrate the stimulatory effect of estrogen on osteoblasts even in the absence of full-length ERα.

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Impact of sex, androgens, and prostate size on C57BL/6J mouse urinary physiology: functional assessment

AJP Renal Physiology ◽

10.1152/ajprenal.00270.2019 ◽

2019 ◽

Vol 317 (4) ◽

pp. F996-F1009 ◽

Cited By ~ 4

Author(s):

Hannah Ruetten ◽

Kyle A. Wegner ◽

Helen L. Zhang ◽

Peiqing Wang ◽

Jaskiran Sandhu ◽

...

Keyword(s):

Clear Understanding ◽

Male Mice ◽

Intact Male ◽

Voiding Function ◽

Castrate Male ◽

Male And Female ◽

Female Mice ◽

Adult Mice ◽

Old Adult ◽

Effective Use

Laboratory mice are used to identify causes of urinary dysfunction including prostate-related mechanisms of lower urinary tract symptoms. Effective use of mice for this purpose requires a clear understanding of molecular, cellular, anatomic, and endocrine contributions to voiding function. Whether the prostate influences baseline voiding function has not been specifically evaluated, in part because most methods that alter prostate mass also change circulating testosterone concentrations. We performed void spot assay and cystometry to establish a multiparameter “baseline” of voiding function in intact male and female 9-wk-old (adult) C57BL/6J mice. We then compared voiding function in intact male mice to that of castrated male mice, male (and female) mice treated with the steroid 5α-reductase inhibitor finasteride, or male mice harboring alleles ( Pbsn4cre/+; R26RDta/+) that significantly reduce prostate lobe mass by depleting prostatic luminal epithelial cells. We evaluated aging-related changes in male urinary voiding. We also treated intact male, castrate male, and female mice with exogenous testosterone to determine the influence of androgen on voiding function. The three methods used to reduce prostate mass (castration, finasteride, and Pbsn4cre/+; R26RDta/+) changed voiding function from baseline but in a nonuniform manner. Castration feminized some aspects of male urinary physiology (making them more like intact female mice) while exogenous testosterone masculinized some aspects of female urinary physiology (making them more like intact male mice). Our results provide evidence that circulating testosterone is responsible in part for baseline sex differences in C57BL/6J mouse voiding function while prostate lobe mass in young, healthy adult mice has a lesser influence.

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EFFECT OF PREPUBERTY CASTRATION ON SUBSEQUENT CANCER IMPLANTATION

Journal of Experimental Medicine ◽

10.1084/jem.42.2.155 ◽

1925 ◽

Vol 42 (2) ◽

pp. 155-161 ◽

Cited By ~ 18

Author(s):

James B. Murphy ◽

Ernest Sturm

Keyword(s):

Adult Life ◽

The Other ◽

Male And Female ◽

Female Mice ◽

Adult Mice ◽

Other Hand ◽

Refractory State ◽

Early Adult Life ◽

Subsequent Cancer

Male and female mice castrated during the first 7 weeks of life and implanted with cancer at later periods show a resistance definitely higher than do intact animals of the same age. This increased refractiveness is evident at 3 months after the operation but is more pronounced at 8 months to a year. Even castration in early adult life seems to increase the refractory state to later cancer inoculation. On the other hand, adult mice inoculated within a week after castration show slight if any evidence of increased resistance.

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Impaired KDM2B-mediated PRC1 recruitment to chromatin causes neural stem cell senescence and ASD/ID-like behavioral deficits

10.1101/2021.09.13.459918 ◽

2021 ◽

Author(s):

Yuen Gao ◽

Natalia Duque-Wilckens ◽

Mohammad B Aljazi ◽

Adam J Moeser ◽

George I Mias ◽

...

Keyword(s):

Molecular Mechanisms ◽

Critical Role ◽

Autism Spectrum ◽

Normal Brain ◽

Behavioral Deficits ◽

Adult Mice ◽

Cycle Arrest ◽

Developing Mouse Brain ◽

Underlying Mechanisms ◽

Polycomb Repressive Complex 1

AbstractAutism spectrum disorder (ASD) and intellectual disability (ID) are neurodevelopmental diseases associated with various genetic mutations. Recent clinical studies report that chromosomal 12q24.31 microdeletions are associated with human ASD/ID. However, the causality and underlying mechanisms linking 12q24.31 microdeletions to ASD/ID pathogenesis remain undetermined. Here we show Kdm2b, one of the genes located in chromosomal 12q24.31, plays a critical role in maintaining neural stem cells (NSCs) in the developing mouse brain. Loss of the CxxC-ZF domain of KDM2B impairs its function in recruiting Polycomb repressive complex 1 (PRC1) to chromatin, resulting in de-repression of genes involved in cell apoptosis, cell cycle arrest, NSC premature senescence, and leading to the loss of NSC populations in the brain. Importantly, the Kdm2b mutation is sufficient to induce ASD/ID-like social and memory deficits in adult mice. Thus, our study reveals a critical role of an epigenetic factor KDM2B in normal brain development, a causality between the Kdm2b mutation and genesis of ASD/ID-like phenotypes in mice, and potential molecular mechanisms linking the function of KDM2B-PRC1 in transcriptional regulation and NSC senescence to the12q24.31 microdeletion-associated ASD/ID.

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Viscoelastic Coagulation Monitor (VCMVet) Reference Intervals and Sex Differences in Mature Adult Mice

Acta Haematologica ◽

10.1159/000516587 ◽

2021 ◽

pp. 1-8

Author(s):

Robert R. Rigor ◽

Linda M. Schutzman ◽

Joseph M. Galante ◽

Ian E. Brown

Keyword(s):

Sex Differences ◽

Molecular Mechanisms ◽

Alpha Angle ◽

Reference Intervals ◽

Coagulation Test ◽

Mature Adult ◽

Male And Female ◽

Female Mice ◽

Adult Mice ◽

Coagulation Status

Introduction: Viscoelastic coagulation tests are useful to assess coagulation status in the clinical setting and to aid in understanding underlying pathophysiological mechanisms that affect coagulation status. Such tests also are useful for coagulation research. Because mouse models are widely used to study molecular mechanisms in fine detail, a simple viscoelastic coagulation test requiring small blood volumes would be convenient for such studies in mice. Methods: We tested viscoelastic coagulation properties of normal healthy adult mice using a novel veterinary clinical point-of-care device, Viscoelastic Coagulation Monitor (VCM Vet™; Entegrion Corp.). Fresh whole blood was collected from 63 healthy mature adult C57 black 6N mice, with ultimately 54 mice, equal numbers of male and females, used to determine reference intervals (RIs) for VCM test parameters. Results: RIs were determined for equal numbers of male and female mice: clot time: 43.0–353.0 s; clot formation time: 49.4–137.6 s; alpha angle: 54.4–62.2°; A10: 25.0–49.6 VCM units; A20: 31.0–56.5 VCM units; maximum clot firmness: 37.6–62.8 VCM units; Lysis Index 30 (Li30): 99.8–100.0%; and Li45: 99.7–100.0%. Significant differences were found between male and female subgroups, where females had higher mean A10 and A20 and median MCF values, indicating greater clot firmness in female versus male mice. Conclusion: VCM Vet is a feasible viscoelastic coagulation test device for studies with mature adult mice, including studying inherent sex differences in coagulation parameters. Inherent differences in coagulability of male and female mice warrant further investigation to determine if such differences underlie greater coagulopathic, hemorrhagic, or thromboembolic risk during trauma or other pathophysiologic conditions.

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