Colin Farquharson

The University of Edinburgh | UoE · Roslin Institute

This study presents the fabrication of carbon‐fiber‐reinforced polyetheretherketone (CF/PEEK) by 3D printing, which is subsequently coated with elastic nanofibers by electrospinning. CF/PEEK is an FDA‐approved implantable material possessing excellent mechanical properties similar to those of human cortical bone. As such, it is a prime candidate fo...

Chronic kidney disease–mineral and bone disorder (CKD-MBD) presents with extra-skeletal calcification and renal osteodystrophy (ROD). The origins of ROD likely lie with elevated uremic toxins and/or an altered hormonal profile but the cellular events responsible remain unclear. Here, we report that stalled mitophagy contributes to mitochondrial dys...

Serum biomarkers are the gold standard in non-invasive disease diagnosis and have tremendous potential as prognostic and theranostic tools for patient stratification. Circulating levels of extracellular matrix molecules are gaining traction as an easily accessible means to assess tissue pathology. However, matrix molecules are large, multimodular p...

Bisphosphonates prevent bone loss in glucocorticoid (GC)-treated boys with Duchenne muscular dystrophy (DMD) and are recommended as standard of care. Targeting receptor activator of nuclear factor kappa-B ligand (RANKL) may have advantages in DMD by ameliorating dystrophic skeletal muscle function in addition to their bone anti-resorptive propertie...

Lipids play a crucial role in signalling and metabolism, regulating the development and maintenance of the skeleton. Membrane lipids have been hypothesised to act as intermediates upstream of orphan phosphatase 1 (PHOSPHO1), a major contributor to phosphate generation required for bone mineralisation. Here, we spatially resolve the lipid atlas of t...

Hypophosphatasia (HPP), caused by loss‐of‐function mutations in the ALPL gene encoding tissue‐nonspecific alkaline phosphatase (TNAP), is characterized by skeletal and dental hypomineralization that can vary in severity from life‐threatening to milder manifestations only in adulthood. PHOSPHO1 deficiency leads to early‐onset scoliosis, osteomalacia...

The administration of intermittent parathyroid hormone (iPTH) is anabolic to the skeleton. Recent studies with cultured osteoblasts have revealed that the expression of PHOSPHO1, a bone‐specific phosphatase essential for the initiation of mineralisation, is regulated by PTH. Therefore, this study sought to determine whether the bone anabolic respon...

Patients with advanced chronic kidney disease (CKD) often present with skeletal abnormalities; a condition known as renal osteodystrophy (ROD). While Tissue-nonspecific alkaline phosphatase (TNAP) and PHOSPHO1 are critical for bone mineralization, their role in the etiology of ROD is unclear. To address this, ROD was induced in both wild-type and P...

Inflammatory Bowel Disease (IBD) is a grouping of chronic inflammatory disorders of the gut. Tenascin-C is a pro-inflammatory, extracellular matrix protein found upregulated in IBD patients and whilst a pathological driver of chronic inflammation, its precise role in the etiology of IBD is unknown. To study tenascin-C’s role in colitis pathology we...

Transforming growth factor β1 (TGF-β1) is a known regulator of chondrocyte proliferation and promotes cartilage repair in osteoarthritis (OA). microRNA-29b-3p (miR-29b-3p) is downregulated by TGF-β1 and overexpressed in OA cartilage. However, the ability of miR-29b-3p to mediate the chondrocyte pro-proliferative effects of TGF-β1 is not yet underst...

Aims Osteoarthritis (OA) is the most prevalent systemic musculoskeletal disorder, characterized by articular cartilage degeneration and subchondral bone (SCB) sclerosis. Here, we sought to examine the contribution of accelerated growth to OA development using a murine model of excessive longitudinal growth. Suppressor of cytokine signalling 2 (SOCS...

Mineralization of the skeleton occurs by several physicochemical and biochemical processes and mechanisms that facilitate the deposition of hydroxyapatite (HA) in specific areas of the extracellular matrix (ECM). Two key phosphatases, phosphatase, orphan 1 (PHOSPHO1) and tissue-non-specific alkaline phosphatase (TNAP), play complementary roles in t...

Short stature and osteoporosis are common in Duchenne muscular dystrophy (DMD) and its pathophysiology may include an abnormality of the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis, which is further exacerbated by long-term glucocorticoid (GC) treatment. Hence an agent that has anabolic properties and may improve linear growth would...

Proton pump inhibitors (PPIs) have been associated with an increased risk of fragility fractures in pharmaco-epidemiological studies. The mechanism is unclear, but it has been speculated that by neutralising gastric acid, they may reduce intestinal calcium absorption, causing secondary hyperparathyroidism and bone loss. Here we investigated that hy...

Bone is now regarded to be a key regulator of a number of metabolic processes, in addition to the regulation of mineral metabolism. However, our understanding of complex bone metabolic interactions at a systems level remains rudimentary. in vitro molecular biology and bioinformatics approaches have frequently been used to understand the mechanistic...

Patients with advanced chronic kidney disease (CKD) often present with skeletal abnormalities; a condition known as renal osteodystrophy (ROD). While Tissue-nonspecific alkaline phosphatase (TNAP) and PHOSPHO1 are recognized to be critical for bone mineralization, their role in the etiology of ROD is unclear. To address this, ROD was induced in bot...

Osteoarthritis is the most prevalent systemic musculoskeletal disorder characterised by articular cartilage degeneration and subchondral bone (SCB) sclerosis. Here we sought to examine the contribution of accelerated growth to osteoarthritis development using a murine model of excessive longitudinal growth. Suppressor of cytokine signalling 2 (SOCS...

Proton pump inhibitors (PPIs) have been associated with an increased risk of fragility fractures in pharmaco-epidemiological studies. The mechanism is unclear but it has been speculated that by neutralising gastric acid, they may reduce intestinal calcium absorption, causing secondary hyperparathyroidism and bone loss. Here we investigated that hyp...

Mammalian Hedgehog (HH) signalling pathway plays an essential role in tissue homeostasis and its deregulation is linked to rheumatological disorders. UBR5 is the mammalian homologue of the E3 ubiquitin-protein ligase Hyd, a negative regulator of the Hh-pathway in Drosophila. To investigate a possible role of UBR5 in regulation of the musculoskeleta...

Bone is now regarded to be a key regulator of a number of metabolic processes, in addition to the regulation of mineral metabolism. However, our understanding of complex bone metabolic interactions at a systems level remains rudimentary, limiting our ability to assess systemic mechanisms underlying diseases and develop novel therapeutics. In vitro...

MicroRNAs are small noncoding RNAs that can bind to the target sites in the 3'-untranslated region of messenger RNA to regulate posttranscriptional gene expression. Increasing evidence has identified the miR-29 family, consisting of miR-29a, miR-29b-1, miR-29b-2, and miR-29c, as key regulators of a number of biological processes. Moreover, their ab...

Multiple dynamic cellular events underlie de novo bone formation. Osteoblasts synthesis, and deposit an extracellular matrix, which together with phosphatases participate in matrix mineralization and the formation of bone. The skeleton affords a number of diverse functions such as a biomechanical and protective scaffold, calcium and phosphorus home...

Supraphysiological levels of the osteoblast‐enriched mineralization regulator ectonucleotide pyrophosphatase or phosphodiesterase‐1 (NPP1) is associated with type 2 diabetes mellitus. We determined the impact of osteoblast‐specific Enpp1 ablation on skeletal structure and metabolic phenotype in mice. Female, but not male, 6‐week‐old mice lacking os...

Biomineralization is a fundamental process key to the development of the skeleton. The phosphatase orphan phosphatase 1 (PHOSPHO1), which likely functions within extracellular matrix vesicles, has emerged as a critical regulator of biomineralization. However, the biochemical pathways that generate intravesicular PHOSPHO1 substrates are currently un...

Tooth resorption (TR) in domestic cats is a common and painful disease characterised by the loss of mineralised tissues from the tooth. Due to its progressive nature and unclear aetiology the only treatment currently available is to extract affected teeth. To gain insight into TR pathogenesis, we characterised the transcriptomic changes involved in...

Background The classical functions of the skeleton encompass locomotion, protection and mineral homeostasis. However, cell-specific gene deletions in the mouse and human genetic studies have identified the skeleton as a key endocrine regulator of metabolism. The bone-specific phosphatase, Phosphatase, Orphan 1 (PHOSPHO1), which is indispensable for...

The skeleton is recognised as a key endocrine regulator of metabolism. Here we show that mice lacking the bone mineralization enzyme PHOSPHO1 (Phospho1-/-) exhibited improved basal glucose homeostasis and resisted high-fat-diet induced weight gain and diabetes. The metabolic protection in Phospho1-/- mice was manifested in the absence of altered le...

The enzyme 11-beta-hydroxysteroid dehydrogenase isoenzyme 2 (11BHSD2) is responsible for converting the active glucocorticoid cortisol to inactive cortisone and in the renal medulla protects the mineralocorticoid receptor (MR) from activation by cortisol. Derangements in 11BHSD2 activity can result in reduced conversion of cortisol to cortisone, ac...

The physiological mineralisation of skeletal tissues, as well as the pathological mineralisation of soft tissues involves a fine balance between regulators that either promote or inhibit the process. In recent years, several studies have advocated a non-skeletal role for some of these mineralisation regulators in a range of human diseases, includin...

E11/Podoplanin (Pdpn) is implicated in early osteocytogenesis and the formation of osteocyte dendrites. This dendritic network is critical for bone modeling/remodeling, through the production of the receptor for receptor activator of nuclear factor κB (RANK)-ligand (RANKL). Despite this, the role of Pdpn in the control of bone remodeling is yet to...

Patients with inflammatory bowel disease (IBD) often present poor bone health and are 40% more at risk of bone fracture. Studies have implicated autophagy in IBD pathology and drugs used to treat IBD stimulate autophagy in varying degrees, however, their effect on the skeleton is currently unknown. Here, we have utilised the dextran sulphate sodium...

The muscular dystrophy x-linked (mdx) mouse is commonly used as a mouse model of Duchenne muscular dystrophy (DMD). Its phenotype is, however, mild and other mouse models have been explored. The mdx:cmah -/- mouse carries a human-like mutation in the Cmah gene and has a severe muscle phenotype, but its growth and bone development are unknown. In th...

Abstract Background Subchondral bone (SCB) thickening is one of the earliest detectable changes in osteoarthritic joints and is considered a potential trigger for subsequent articular cartilage degeneration. In this manuscript, we examine whether disruption to the SCB osteocyte network contributes to the initiation and pathogenesis of osteoarthriti...

Since its characterization two decades ago, the phosphatase PHOSPHO1 has been the subject of an increasing focus of research. This work has elucidated PHOSPHO1's central role in the biomineralization of bone and other hard tissues, but has also implicated the enzyme in other biological processes in health and disease. During mineralization PHOSPHO1...

Matrix vesicles (MVs) are a class of extracellular vesicles that initiate mineralization in cartilage, bone, and other vertebrate tissues by accumulating calcium ions (Ca2+) and inorganic phosphate (Pi) within their lumen and forming a nucleation core (NC). After further sequestration of Ca2+ and Pi, the NC transforms into crystalline complexes. Di...

Glucocorticoids (GCs) are associated with many adverse effects including osteoporosis and growth retardation. These are particular problems in Duchenne muscular dystrophy (DMD) where GCs form the mainstay of treatment. The mechanisms that underlie the undesirable effects of GCs on skeletal development are unclear and there is no proven treatment. W...

Advanced next generation sequencing approaches have started to reveal the cellular and molecular complexity of the microenvironment in many tissues. It is challenging to obtain high quality RNA from mineralised tissues. We developed an optimised method of RNA extraction from feline teeth collected in a clinical setting and at post mortem. Teeth wer...

The authors regret that the original version of the above article contained errors in the Figs. 3, 4 and Tables 3 legends. The errors has been corrected.

ENPP1 is well known for its role in regulating skeletal and soft tissue mineralization. It primarily exerts its function through the generation of pyrophosphate, a key inhibitor of hydroxyapatite formation. Several previous studies have suggested that ENPP1 also contributes to a range of human diseases including diabetes, cancer, cardiovascular dis...

The ex vivo organ culture of bone provides many of the advantages of both the whole organism and isolated cell strategies and can deliver valuable insight into the network of processes and activities that are fundamental to bone and cartilage biology. Through maintaining the bone and/or cartilage cells in their native environment, this model system...

Figure S1. Immunofluorescence microscopy showing goat IgG control in MC3T3 cells counterstained with DAPI Table S1. Sequences and source of primers used Table S2. Primary antibodies used Table S3. Secondary antibodies used

Objectives Bone fracture healing is regulated by a series of complex physicochemical and biochemical processes. One of these processes is bone mineralization, which is vital for normal bone development. Phosphatase, orphan 1 (PHOSPHO1), a skeletal tissue-specific phosphatase, has been shown to be involved in the mineralization of the extracellular...

Key Points PHOSPHO1 regulates phosphocholine metabolism, ATP production, and amino acid supply during erythropoiesis.

Individuals with inflammatory bowel disease (IBD) often present with poor bone health. The development of targeted therapies for this bone loss requires a fuller understanding of the underlying cellular mechanisms. Although bone loss in IBD is multifactorial the altered sensitivity and secretion of growth hormone (GH) and insulin-like growth factor...

E11/podoplanin is critical in the early stages of osteoblast-to-osteocyte transitions (osteocytogenesis) however the upstream events which regulate E11 expression are unknown. The aim of this study was to examine the effects of FGF-2 on E11-mediated osteocytogenesis and to reveal the nature of the underlying signaling pathways regulating this proce...

Calcific aortic valve disease (CAVD) involves progressive valve leaflet thickening and severe calcification, impairing leaflet motion. The in vitro calcification of primary rat, human, porcine and bovine aortic valve interstitial cells (VICs) is commonly employed to investigate CAVD mechanisms. However, to date, no published studies have utilised c...

The skeletal disorders causing the most severe welfare problems in different classes of poultry are bone growth disorders in young birds and bone fragility in older laying hens. Angular and rotational deformities of leg bones are widespread in young birds, especially in broilers but also in turkeys. Dyschondroplasia is a widely observed defect in t...

Calcific aortic valve disease (CAVD) is characterized by the progressive thickening of the aortic valve leaflets. It is a condition frequently found in the elderly and end-stage renal disease (ESRD) patients, who commonly suffer from hyperphosphatemia and hypercalcemia. At present, there are no medication therapies that can stop its progression. Th...

Figure S1. Gait analysis of 6‐week old male fl/fl and cKO mice (n = 4/genotype/sex). Data are represented as mean ± S.E.M. Table S1. Gait parameters explored in this study.

Glucocorticoids (GCs) are effective for the treatment of many chronic conditions but their use is associated with frequent and wide-ranging adverse effects including osteoporosis and growth retardation. The mechanisms that underlie the undesirable effects of GCs on skeletal development are unclear and there is no proven effective treatment to comba...

The transport of mineral ions from the enamel organ-associated blood vessels to the developing enamel crystals involves complex cargo packaging and carriage mechanisms across several cell layers, including the ameloblast layer and the stratum intermedium. Previous studies have established PHOSPHO1 as a matrix vesicle membrane-associated phosphatase...

Mineralization is a key process in the formation of bone and cartilage in vertebrates, involving the deposition of calcium and phosphate containing hydroxyapatite (HA) mineral within a collagenous matrix. Inorganic phosphate (Pi) accumulation within matrix vesicles (MVs) is a fundamental stage in the precipitation of HA, with PHOSPHO1 being identif...

The phosphatase PHOSPHO1 is involved in the initiation of biomineralisation. Bones in Phospho1 knockout (KO) mice show histological osteomalacia with frequent bowing of long bones and spontaneous fractures: they contain less mineral, with smaller mineral crystals. However, the consequences ofPhospho1 ablation on the microscale structure of bone are...

The transmembrane glycoprotein E11/Podoplanin (Pdpn) has been implicated in the initial stages of osteocyte differentiation. However, its precise function and regulatory mechanisms are still unknown. Due to the known embryonic lethality induced by global Pdpn deletion, we have herein explored the effect of bone specific Pdpn knockdown on osteocyte...

Throughout the last decade, significant developments in cellular, molecular, and mouse models have revealed major endocrine functions of the skeleton. More recent studies have evolved the interplay between bone-specific hormones, the skeleton, marrow adipose tissue, muscle and the brain. This review focuses on literature from the last decade, addre...