Histone Deacetylases in Bone Development and Skeletal Disorders

Histone deacetylases (Hdacs) are conserved enzymes that remove acetyl groups from lysine side chains in histones and other proteins. Eleven of the 18 Hdacs encoded by the human and mouse genomes depend on Zn2+ for enzymatic activity, while the other 7, the sirtuins (Sirts), require NAD2+. Collectively, Hdacs and Sirts regulate numerous cellular and mitochondrial processes including gene transcription, DNA repair, protein stability, cytoskeletal dynamics, and signaling pathways to affect both development and aging. Of clinical relevance, Hdacs inhibitors are United States Food and Drug Administration-approved cancer therapeutics and are candidate therapies for other common diseases including arthritis, diabetes, epilepsy, heart disease, HIV infection, neurodegeneration, and numerous aging-related disorders. Hdacs and Sirts influence skeletal development, maintenance of mineral density and bone strength by affecting intramembranous and endochondral ossification, as well as bone resorption. With few exceptions, inhibition of Hdac or Sirt activity though either loss-of-function mutations or prolonged chemical inhibition has negative and/or toxic effects on skeletal development and bone mineral density. Specifically, Hdac/Sirt suppression causes abnormalities in physiological development such as craniofacial dimorphisms, short stature, and bone fragility that are associated with several human syndromes or diseases. In contrast, activation of Sirts may protect the skeleton from aging and immobilization-related bone loss. This knowledge may prolong healthspan and prevent adverse events caused by epigenetic therapies that are entering the clinical realm at an unprecedented rate. In this review, we summarize the general properties of Hdacs/Sirts and the research that has revealed their essential functions in bone forming cells (e.g., osteoblasts and chondrocytes) and bone resorbing osteoclasts. Finally, we offer predictions on future research in this area and the utility of this knowledge for orthopedic applications and bone tissue engineering.

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hdac4 mediates perichondral ossification and pharyngeal skeleton development in the zebrafish

PeerJ ◽

10.7717/peerj.6167 ◽

2019 ◽

Vol 7 ◽

pp. e6167 ◽

Cited By ~ 2

Author(s):

April DeLaurier ◽

Cynthia Lizzet Alvarez ◽

Kali J Wiggins

Keyword(s):

Histone Deacetylases ◽

Stop Codon ◽

Skeletal Development ◽

Premature Stop Codon ◽

Early Embryo ◽

Loss Of Function ◽

Larval Stages ◽

Chondrocyte Maturation ◽

Expression Of Genes ◽

Maternal Contribution

Background Histone deacetylases (HDACs) are epigenetic factors that function to repress gene transcription by removing acetyl groups from the N-terminal of histone lysines. Histone deacetylase 4 (HDAC4), a class IIa HDAC, has previously been shown to regulate the process of endochondral ossification in mice via repression of Myocyte enhancer factor 2c (MEF2C), a transcriptional activator of Runx2, which in turn promotes chondrocyte maturation and production of bone by osteoblasts. Methods & Materials In this study, we generated two zebrafish lines with mutations in hdac4 using CRISPR/Cas9 and analyzed mutants for skeletal phenotypes and expression of genes known to be affected by Hdac4 expression. Results Lines have insertions causing a frameshift in a proximal exon of hdac4 and a premature stop codon. Mutations are predicted to result in aberrant protein sequence and a truncated protein, eliminating the Mef2c binding domain and Hdac domain. Zygotic mutants from two separate lines show a significant increase in ossification of pharyngeal ceratohyal cartilages at 7 days post fertilization (dpf) (p < 0.01, p < 0.001). At 4 dpf, mutant larvae have a significant increase of expression of runx2a and runx2b in the ceratohyal cartilage (p < 0.05 and p < 0.01, respectively). A subset of maternal-zygotic (mz) mutant and heterozygote larvae (40%) have dramatically increased ossification at 7 dpf compared to zygotic mutants, including formation of a premature anguloarticular bone and mineralization of the first and second ceratobranchial cartilages and symplectic cartilages, which normally does not occur until fish are approximately 10 or 12 dpf. Some maternal-zygotic mutants and heterozygotes show loss of pharyngeal first arch elements (25.9% and 10.2%, respectively) and neurocranium defects (30.8% and 15.2%, respectively). Analysis of RNA-seq mRNA transcript levels and in situ hybridizations from zygotic stages to 75–90% epiboly indicates that hdac4 is highly expressed in early embryos, but diminishes by late epiboly, becoming expressed again in larval stages. Discussion Loss of function of hdac4 in zebrafish is associated with increased expression of runx2a and runx2b targets indicating that a role for hdac4 in zebrafish is to repress activation of ossification of cartilage. These findings are consistent with observations of precocious cartilage ossification in Hdac4 mutant mice, demonstrating that the function of Hdac4 in skeletal development is conserved among vertebrates. Expression of hdac4 mRNA in embryos younger than 256–512 cells indicates that there is a maternal contribution of hdac4 to the early embryo. The increase in ossification and profound loss of first pharyngeal arch elements and anterior neurocranium in a subset of maternal-zygotic mutant and heterozygote larvae suggests that maternal hdac4 functions in cartilage ossification and development of cranial neural crest-derived structures.

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Smpd3Expression in both Chondrocytes and Osteoblasts Is Required for Normal Endochondral Bone Development

Molecular and Cellular Biology ◽

10.1128/mcb.01077-15 ◽

2016 ◽

Vol 36 (17) ◽

pp. 2282-2299 ◽

Cited By ~ 13

Author(s):

Jingjing Li ◽

Garthiga Manickam ◽

Seemun Ray ◽

Chun-do Oh ◽

Hideyo Yasuda ◽

...

Keyword(s):

Bone Development ◽

Skeletal Development ◽

Loss Of Function ◽

Endochondral Bone ◽

Transgenic Expression ◽

Phosphodiesterase 3 ◽

Skeletal Phenotype ◽

Metabolizing Enzyme ◽

Bone Abnormalities ◽

And Cartilage

Sphingomyelin phosphodiesterase 3 (SMPD3), a lipid-metabolizing enzyme present in bone and cartilage, has been identified to be a key regulator of skeletal development. A homozygous loss-of-function mutation called fragilitas ossium (fro) in theSmpd3gene causes poor bone and cartilage mineralization resulting in severe congenital skeletal deformities. Here we show thatSmpd3expression in ATDC5 chondrogenic cells is downregulated by parathyroid hormone-related peptide through transcription factor SOX9. Furthermore, we show that transgenic expression ofSmpd3in the chondrocytes offro/fromice corrects the cartilage but not the bone abnormalities. Additionally, we report the generation ofSmpd3flox/floxmice for the tissue-specific inactivation ofSmpd3using the Cre-loxPsystem. We found that the skeletal phenotype inSmpd3flox/flox; Osx-Cremice, in which theSmpd3gene is ablated in both late-stage chondrocytes and osteoblasts, closely mimics the skeletal phenotype infro/fromice. On the other hand,Smpd3flox/flox;Col2a1-Cremice, in which theSmpd3gene is knocked out in chondrocytes only, recapitulate thefro/fromouse cartilage phenotype. This work demonstrates thatSmpd3expression in both chondrocytes and osteoblasts is required for normal endochondral bone development.

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Early-Onset Osteoporosis

Calcified Tissue International ◽

10.1007/s00223-021-00885-6 ◽

2021 ◽

Author(s):

Outi Mäkitie ◽

M. Carola Zillikens

Keyword(s):

Young Adults ◽

Early Onset ◽

Type I Collagen ◽

Young Patients ◽

Fragility Fractures ◽

Underlying Disease ◽

Bone Fragility ◽

Sphingolipid Metabolism ◽

Type I ◽

Loss Of Function

AbstractOsteoporosis is a skeletal disorder with enhanced bone fragility, usually affecting the elderly. It is very rare in children and young adults and the definition is not only based on a low BMD (a Z-score < − 2.0 in growing children and a Z-score ≤ − 2.0 or a T-score ≤ − 2.5 in young adults) but also on the occurrence of fragility fractures and/or the existence of underlying chronic diseases or secondary factors such as use of glucocorticoids. In the absence of a known chronic disease, fragility fractures and low BMD should prompt extensive screening for secondary causes, which can be found in up to 90% of cases. When fragility fractures occur in childhood or young adulthood without an evident secondary cause, investigations should explore the possibility of an underlying monogenetic bone disease, where bone fragility is caused by a single variant in a gene that has a major role in the skeleton. Several monogenic forms relate to type I collagen, but other forms also exist. Loss-of-function variants in LRP5 and WNT1 may lead to early-onset osteoporosis. The X-chromosomal osteoporosis caused by PLS3 gene mutations affects especially males. Another recently discovered form relates to disturbed sphingolipid metabolism due to SGMS2 mutations, underscoring the complexity of molecular pathology in monogenic early-onset osteoporosis. Management of young patients consists of treatment of secondary factors, optimizing lifestyle factors including calcium and vitamin D and physical exercise. Treatment with bone-active medication should be discussed on a personalized basis, considering the severity of osteoporosis and underlying disease versus the absence of evidence on anti-fracture efficacy and potential harmful effects in pregnancy.

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Duration of Bisphosphonate Drug Holidays in Osteoporosis Patients: A Narrative Review of the Evidence and Considerations for Decision-Making

Journal of Clinical Medicine ◽

10.3390/jcm10051140 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1140

Author(s):

Kaleen N. Hayes ◽

Elizabeth M. Winter ◽

Suzanne M. Cadarette ◽

Andrea M. Burden

Keyword(s):

Surrogate Marker ◽

Femoral Fractures ◽

Osteonecrosis Of The Jaw ◽

Bisphosphonate Therapy ◽

Narrative Review ◽

Drug Holiday ◽

Future Research ◽

Mineral Density ◽

First Line Therapy

Bisphosphonates are first-line therapy for osteoporosis, with alendronate, risedronate, and zoledronate as the main treatments used globally. After one year of therapy, bisphosphonates are retained in bone for extended periods with extended anti-fracture effects after discontinuation. Due to this continued fracture protection and the potential for rare adverse events associated with long-term use (atypical femoral fractures and osteonecrosis of the jaw), a drug holiday of two to three years is recommended for most patients after long-term bisphosphonate therapy. The recommendation for a drug holiday up to three years is derived primarily from extensions of pivotal trials with alendronate and zoledronate and select surrogate marker studies. However, certain factors may modify the duration of bisphosphonate effects on a drug holiday and warrant consideration when determining an appropriate time off-therapy. In this narrative review, we recall what is currently known about drug holidays and discuss what we believe to be the primary considerations and areas for future research regarding drug holiday duration: total bisphosphonate exposure, type of bisphosphonate used, bone mineral density and falls risk, and patient sex and body weight.

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Somatic production of reactive oxygen species does not predict its production in sperm cells across Drosophila melanogaster lines

BMC Research Notes ◽

10.1186/s13104-021-05550-7 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Biz R. Turnell ◽

Luisa Kumpitsch ◽

Anne-Cécile Ribou ◽

Klaus Reinhardt

Keyword(s):

Reactive Oxygen Species ◽

Drosophila Melanogaster ◽

Reactive Oxygen ◽

Future Research ◽

Ros Production ◽

Oxygen Species ◽

Loss Of Function ◽

Wild Type ◽

Ros Scavenging ◽

Transport Chain

Abstract Objective Sperm ageing has major evolutionary implications but has received comparatively little attention. Ageing in sperm and other cells is driven largely by oxidative damage from reactive oxygen species (ROS) generated by the mitochondria. Rates of organismal ageing differ across species and are theorized to be linked to somatic ROS levels. However, it is unknown whether sperm ageing rates are correlated with organismal ageing rates. Here, we investigate this question by comparing sperm ROS production in four lines of Drosophila melanogaster that have previously been shown to differ in somatic mitochondrial ROS production, including two commonly used wild-type lines and two lines with genetic modifications standardly used in ageing research. Results Somatic ROS production was previously shown to be lower in wild-type Oregon-R than in wild-type Dahomey flies; decreased by the expression of alternative oxidase (AOX), a protein that shortens the electron transport chain; and increased by a loss-of-function mutation in dj-1β, a gene involved in ROS scavenging. Contrary to predictions, we found no differences among these four lines in the rate of sperm ROS production. We discuss the implications of our results, the limitations of our study, and possible directions for future research.

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Loss of Wnt16 Leads to Skeletal Deformities and Downregulation of Bone Developmental Pathway in Zebrafish

International Journal of Molecular Sciences ◽

10.3390/ijms22136673 ◽

2021 ◽

Vol 22 (13) ◽

pp. 6673

Author(s):

Xiaochao Qu ◽

Mei Liao ◽

Weiwei Liu ◽

Yisheng Cai ◽

Qiaorong Yi ◽

...

Keyword(s):

Gene Knockout ◽

Integration Site ◽

Skeletal Development ◽

Rna Seq ◽

Developmental Pathway ◽

Mineral Density ◽

Zebrafish Model ◽

Protein Protein Interaction ◽

Ct Analysis

Wingless-type MMTV integration site family, member 16 (wnt16), is a wnt ligand that participates in the regulation of vertebrate skeletal development. Studies have shown that wnt16 can regulate bone metabolism, but its molecular mechanism remains largely undefined. We obtained the wnt16-/- zebrafish model using the CRISPR-Cas9-mediated gene knockout screen with 11 bp deletion in wnt16, which led to the premature termination of amino acid translation and significantly reduced wnt16 expression, thus obtaining the wnt16-/- zebrafish model. The expression of wnt16 in bone-related parts was detected via in situ hybridization. The head, spine, and tail exhibited significant deformities, and the bone mineral density and trabecular bone decreased in wnt16-/- using light microscopy and micro-CT analysis. RNA sequencing was performed to explore the differentially expressed genes (DEGs). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis found that the down-regulated DEGs are mainly concentrated in mTOR, FoxO, and VEGF pathways. Protein–protein interaction (PPI) network analysis was performed with the detected DEGs. Eight down-regulated DEGs including akt1, bnip4, ptena, vegfaa, twsg1b, prkab1a, prkab1b, and pla2g4f.2 were validated by qRT-PCR and the results were consistent with the RNA-seq data. Overall, our work provides key insights into the influence of wnt16 gene on skeletal development.

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MECHANISMS IN ENDOCRINOLOGY: Mechanisms and evaluation of bone fragility in type 1 diabetes mellitus

Acta Endocrinologica ◽

10.1530/eje-15-0820 ◽

2016 ◽

Vol 174 (4) ◽

pp. R127-R138 ◽

Cited By ~ 66

Author(s):

F S Hough ◽

D D Pierroz ◽

C Cooper ◽

S L Ferrari ◽

_ _

Keyword(s):

Diabetes Mellitus ◽

Type 1 Diabetes ◽

Type 1 Diabetes Mellitus ◽

Bone Fragility ◽

Mineral Density ◽

Good Glycaemic Control ◽

Marrow Adiposity ◽

Igf1 Deficiency

Subjects with type 1 diabetes mellitus (T1DM) have decreased bone mineral density and an up to sixfold increase in fracture risk. Yet bone fragility is not commonly regarded as another unique complication of diabetes. Both animals with experimentally induced insulin deficiency syndromes and patients with T1DM have impaired osteoblastic bone formation, with or without increased bone resorption. Insulin/IGF1 deficiency appears to be a major pathogenetic mechanism involved, along with glucose toxicity, marrow adiposity, inflammation, adipokine and other metabolic alterations that may all play a role on altering bone turnover. In turn, increasing physical activity in children with diabetes as well as good glycaemic control appears to provide some improvement of bone parameters, although robust clinical studies are still lacking. In this context, the role of osteoporosis drugs remains unknown.

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Secondary Functions of Arginine and Sulfur Amino Acids in Poultry Health: Review

Animals ◽

10.3390/ani10112106 ◽

2020 ◽

Vol 10 (11) ◽

pp. 2106

Author(s):

Fernanda Lima de Souza Castro ◽

Woo K. Kim

Keyword(s):

Amino Acids ◽

Heat Stress ◽

Bone Mineral ◽

Bone Development ◽

Sulfur Amino Acids ◽

Mineral Density ◽

Eimeria Spp ◽

Nutritional Strategies ◽

Eimeria Infection ◽

Health Review

Amino acids such as arginine, methionine, and cysteine are the precursors of essential molecules that regulate growth and health, being classified as functional amino acids. This review describes the metabolism of arginine and the sulfur amino acids and how they modulate, directly or indirectly, different tissues. Emphasis is placed on their effects in supporting health during challenging conditions, such as heat stress and Eimeria infection. The use of arginine has been shown to reduce abdominal fat pad in ducks and increase lean tissue and bone mineral density in broilers. Additionally, the sulfur amino acids have been shown to improve bone development and are beneficial during heat stress. The use of L-methionine increased the cortical and trabecular bone mineral densities, in laying hens. Moreover, the dietary inclusion of these amino acids could reduce the damage caused by Eimeria spp. infection by regulating the antioxidant system and cell repair. Understanding how these amino acids can mitigate stressful conditions may provide us novel insights of their use as nutritional strategies to modulate the health status of chickens.

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Clinical, Genetics, and Bioinformatic Characterization of Mutations Affecting an Essential Region of PLS3 in Patients with BMND18

International Journal of Endocrinology ◽

10.1155/2018/8953217 ◽

2018 ◽

Vol 2018 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Ting Chen ◽

Haiying Wu ◽

Chenxi Zhang ◽

Jiarong Feng ◽

Linqi Chen ◽

...

Keyword(s):

Novel Mutation ◽

Homology Modelling ◽

Gene Sequencing ◽

Bioinformatic Analysis ◽

Actin Binding ◽

Clinical Genetics ◽

Loss Of Function ◽

Mineral Density ◽

Trait Locus ◽

The Impact

Background. Bone mineral density quantitative trait locus 18 (BMND18, OMIM #300910) is a type of early-onset osteogenesis imperfecta (OI) caused by loss-of-function mutations in the PLS3 gene, which encodes plastin-3, a key protein in the formation of actin bundles throughout the cytoskeleton. Here, we report a patient with PLS3 mutation caused BMND18 and evaluated all the reported disease-causing mutations by bioinformatic analysis. Methods. Targeted gene sequencing was performed to find the disease-causing mutation in our patient. Bioinformatic analyses mainly including homology modelling and molecular dynamics stimulation were conducted to explore the impact of the previously reported mutations on plastin-3. Results. Gene sequencing showed a novel nonsense mutation (c.745G > T, p.E249X), which locates at a highly conserved region containing residues p.240–266 (LOOP-1) in the PLS3 gene. Further bioinformatic analyses of the previously reported mutations revealed that LOOP-1 is predicted to physically connect the calponin-homology 1 (CH1) and CH2 domains of the ABD1 fragment and spatially locates within the interface of ABD1 and ABD2. It is crucial to the conformation transition and actin-binding function of plastin-3. Conclusions. This report identified a novel mutation that truncates the PLS3 gene. Moreover, bioinformatic analyses of the previous reported mutations in PLS3 gene lead us to find a critical LOOP-1 region of plastin-3 mutations at which may be detrimental to the integral conformation of plastin-3 and thus affect its binding to actin filament.

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“My World Has Expanded Even Though I'm Stuck at Home”: Experiences of Individuals With Amyotrophic Lateral Sclerosis Who Use Augmentative and Alternative Communication and Social Media

American Journal of Speech-Language Pathology ◽

10.1044/2015_ajslp-15-0010 ◽

2015 ◽

Vol 24 (4) ◽

pp. 680-695 ◽

Cited By ~ 22

Author(s):

Jessica Caron ◽

Janice Light

Keyword(s):

Social Media ◽

Amyotrophic Lateral Sclerosis ◽

Augmentative And Alternative Communication ◽

Future Research ◽

Loss Of Function ◽

Alternative Communication ◽

Communication Modes ◽

Communication Needs ◽

Use Of Social Media ◽

Lateral Sclerosis

PurposeThis study aimed to expand the current understanding of how persons with amyotrophic lateral sclerosis (pALS) use augmentative and alternative communication and social media to address their communication needs.MethodAn online focus group was used to investigate the experiences of 9 pALS who use augmentative and alternative communication and social media. Questions posed to the group related to (a) current use of social media, (b) advantages of social media, (c) barriers to independent use, (d) supports to independent use, and (e) recommendations for developers, policy makers, and other pALS.ResultsParticipants primarily reported that use of social media was a beneficial tool that provided increased communication opportunities, connections to communication partners, and networks of support. Specific results are discussed with reference to the research as well as implications for practice and recommendations for future research.ConclusionsAs individuals with ALS experience loss of function, some communication modes may no longer be viable. Providing access to different modes of communication, including social media, can allow independence, participation and better quality of life.

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