Effects of in utero delta-9-tetrahydrocannabinol (THC) exposure on fetal and infant musculoskeletal development in a preclinical nonhuman primate model.

The endocannabinoid system (ECS) plays a major role in the maintenance of bodily homeostasis and adaptive response to external insults. It has been shown to regulate crucial physiological processes and behaviors, spanning nervous functions, anxiety, cognition, and pain sensation. Due to this broad activity, the ECS has been explored as a potential therapeutic target in the treatment of select diseases. However, until there is a more comprehensive understanding of how ECS activation by exogenous and endogenous ligands manifests across disparate tissues and cells, discretion should be exercised. Previous work has investigated how endogenous cannabinoid signaling impacts skeletal muscle development and differentiation. However, the effects of activation of the ECS by delta-9-tetrahydrocannabinol (THC, the most psychoactive component of cannabis) on skeletal muscle development, particularly in utero, remain unclear. To address this research gap, we used a highly translational non-human primate model to examine the potential impact of chronic prenatal THC exposure on fetal and infant musculoskeletal development. RNA was isolated from the skeletal muscle and analyzed for differential gene expression using a Nanostring nCounter neuroinflammatory panel comprised of 770 genes. Histomorphological evaluation of muscle morphology and composition was also performed. Our findings suggest that while prenatal THC exposure had narrow overall effects on fetal and infant muscle development, the greatest impacts were observed within pathways related to inflammation and cytokine signaling, which suggest the potential for tissue damage and atrophy. This pilot study establishes feasibility to evaluate neuroinflammation due to prenatal THC exposure and provides rationale for follow-on studies that explore the longer-term implications and functional consequences encountered by offspring as they continue to mature.

Genetic models for lineage tracing in musculoskeletal development, injury, and healing.

Musculoskeletal development and later post-natal homeostasis are highly dynamic processes, marked by rapid structural and functional changes across very short periods of time. Adult anatomy and physiology are derived from pre-existing cellular and biochemical states. Consequently, these early developmental states guide and predict the future of the system as a whole. Tools have been developed to mark, trace, and follow specific cells and their progeny either from one developmental state to the next or between circumstances of health and disease. There are now many such technologies alongside a library of molecular markers which may be utilized in conjunction to allow for precise development of unique cell 'lineages'. In this review, we first describe the development of the musculoskeletal system beginning as an embryonic germ layer and at each of the key developmental stages that follow. We then discuss these structures in the context of adult tissues during homeostasis, injury, and repair. Special focus is given in each of these sections to the key genes involved which may serve as markers of lineage or later in post-natal tissues. We then finish with a technical assessment of lineage tracing and the techniques and technologies currently used to mark cells, tissues, and structures within the musculoskeletal system.

Musculoskeletal Development and Skeletal Pathophysiology's.

Musculoskeletal (MSK) disorders are one of the leading causes of disability for people of all ages and impart significant socio-economic burdens on society [...].

Anxiety and Cognition in Cre- Collagen Type II Sirt1 K/O Male Mice.

Introduction: Using transgenic collagen type II-specific Sirt1 knockout (CKO) mice we studied the role of Sirt1 in nutritional induced catch up growth (CUG) and we found that these mice have a less organized growth plate and reduced efficiency of CUG. In addition, we noted that they weigh more than control (CTL) mice. Studying the reason for the increased weigh, we found differences in activity and brain function. Methods: Several tests for behavior and activity were used: open field; elevated plus maze, Morris water maze, and home cage running wheels. The level of Glu- osteocalcin, known to connect bone and brain function, was measured by Elisa; brain Sirt1 was analyzed by western blot. Results: We found that CKO mice had increased anxiety, with less spatial memory, learning capabilities and reduced activity in their home cages. No significant differences were found between CKO and CTL mice in Glu- osteocalcin levels; nor in the level of brain SIRT1. Discussion/Conclusion: Using transgenic collagen type II-specific Sirt1 knockout (CKO) mice we found a close connection between linear growth and brain function. Using a collagen type II derived system we affected a central regulatory mechanism leading to hypo activity, increased anxiety, and slower learning, without affecting circadian period. As children with idiopathic short stature are more likely to have lower IQ, with substantial deficits in working memory than healthy controls, the results of the current study suggest that SIRT1 may be the underlying factor connecting growth and brain function.

Tissue-Specific Decellularized Extracellular Matrix Bioinks for Musculoskeletal Tissue Regeneration and Modeling Using 3D Bioprinting Technology.

The musculoskeletal system is a vital body system that protects internal organs, supports locomotion, and maintains homeostatic function. Unfortunately, musculoskeletal disorders are the leading cause of disability worldwide. Although implant surgeries using autografts, allografts, and xenografts have been conducted, several adverse effects, including donor site morbidity and immunoreaction, exist. To overcome these limitations, various biomedical engineering approaches have been proposed based on an understanding of the complexity of human musculoskeletal tissue. In this review, the leading edge of musculoskeletal tissue engineering using 3D bioprinting technology and musculoskeletal tissue-derived decellularized extracellular matrix bioink is described. In particular, studies on in vivo regeneration and in vitro modeling of musculoskeletal tissue have been focused on. Lastly, the current breakthroughs, limitations, and future perspectives are described.

PKA and PKC Balance in Synapse Elimination during Neuromuscular Junction Development.

During the development of the nervous system, synaptogenesis occurs in excess though only the appropriate connections consolidate. At the neuromuscular junction, competition between several motor nerve terminals results in the maturation of a single axon and the elimination of the others. The activity-dependent release of transmitter, cotransmitters, and neurotrophic factors allows the direct mutual influence between motor axon terminals through receptors such as presynaptic muscarinic ACh autoreceptors and the tropomyosin-related kinase B neurotrophin receptor. In previous studies, we investigated the synergistic and antagonistic relations between these receptors and their downstream coupling to PKA and PKC pathways and observed a metabotropic receptor-driven balance between PKA (stabilizes multinnervation) and PKC (promotes developmental axonal loss). However, how much does each kinase contribute in the developmental synapse elimination process? A detailed statistical analysis of the differences between the PKA and PKC effects in the synapse elimination could help to explore this point. The present short communication provides this analysis and results show that a similar level of PKA inhibition and PKC potentiation would be required during development to promote synapse loss.

CSF1R-dependent macrophages control postnatal somatic growth and organ maturation.

Homozygous mutation of the Csf1r locus (Csf1rko) in mice, rats and humans leads to multiple postnatal developmental abnormalities. To enable analysis of the mechanisms underlying the phenotypic impacts of Csf1r mutation, we bred a rat Csf1rko allele to the inbred dark agouti (DA) genetic background and to a Csf1r-mApple reporter transgene. The Csf1rko led to almost complete loss of embryonic macrophages and ablation of most adult tissue macrophage populations. We extended previous analysis of the Csf1rko phenotype to early postnatal development to reveal impacts on musculoskeletal development and proliferation and morphogenesis in multiple organs. Expression profiling of 3-week old wild-type (WT) and Csf1rko livers identified 2760 differentially expressed genes associated with the loss of macrophages, severe hypoplasia, delayed hepatocyte maturation, disrupted lipid metabolism and the IGF1/IGF binding protein system. Older Csf1rko rats developed severe hepatic steatosis. Consistent with the developmental delay in the liver Csf1rko rats had greatly-reduced circulating IGF1. Transfer of WT bone marrow (BM) cells at weaning without conditioning repopulated resident macrophages in all organs, including microglia in the brain, and reversed the mutant phenotypes enabling long term survival and fertility. WT BM transfer restored osteoclasts, eliminated osteopetrosis, restored bone marrow cellularity and architecture and reversed granulocytosis and B cell deficiency. Csf1rko rats had an elevated circulating CSF1 concentration which was rapidly reduced to WT levels following BM transfer. However, CD43hi non-classical monocytes, absent in the Csf1rko, were not rescued and bone marrow progenitors remained unresponsive to CSF1. The results demonstrate that the Csf1rko phenotype is autonomous to BM-derived cells and indicate that BM contains a progenitor of tissue macrophages distinct from hematopoietic stem cells. The model provides a unique system in which to define the pathways of development of resident tissue macrophages and their local and systemic roles in growth and organ maturation.

Alteraciones musculoesqueléticas y adaptaciones biomecánicas durante los trimestres de embarazo: una revisión sistemática / Musculoskeletal changes and biomechanic adaptations during the three trimesters of pregnancy: a sistematic review

Resumen Quesada Salazar, N. (2021). Alteraciones musculoesqueléticas y adaptaciones biomecánicas durante los trimestres de embarazo: una revisión sistemática. PENSAR EN MOVIMIENTO: Revista de Ciencias del Ejercicio y la Salud, 19(1), 1-27. El embarazo es un proceso progresivo que involucra cambios de tipo hormonal, mecánico, fisiológico y emocional en la mujer y que causa que el sistema musculoesquelético se adapte constantemente. Estos cambios suelen identificarse a través de la postura y la biomecánica de los movimientos en la vida diaria. En esta investigación, se realizó una revisión sistemática para encontrar las principales alteraciones y adaptaciones durante el embarazo, incluyendo artículos del 2008 al 2018, con mujeres gestantes sanas, con un solo feto, sin alteraciones musculoesqueléticas previas, de Índice de Masa Corporal (IMC) normal y cualquier metodología de investigación excepto estudios de caso. Se identificaron 13 estudios que refieren evaluar las tres etapas de gestación, edades desde los 20 a los 35 años, así como con diversos objetivos de investigación. La postura de la mujer gestante presenta un aumento de la lordosis lumbar, la curvatura torácica y el ángulo de inclinación anterior de la pelvis. La tarea de sentarse y levantarse de una silla requiere de mayor control del movimiento, así como de tiempo de ejecución. La oscilación y las fuerzas de reacción del suelo del Centro de Presión corporal aumentan al estar de pie, lo que resulta en una mayor distancia entre los pies, como estrategia de control del equilibrio. Finalmente, la biomecánica de la marcha se adapta a una menor velocidad, longitud de paso y etapa de despegue de los pies del piso, con un aumento del ancho de paso y una mayor base de apoyo. En la gestación, la mujer desarrolla adaptaciones de tipo anatómicas y mecánicas como respuesta a los cambios progresivos experimentados.

Abstract Quesada Salazar, N. (2021). Musculoskeletal changes and biomechanic adaptations during the three trimesters of pregnancy: a sistematic review. PENSAR EN MOVIMIENTO: Revista de Ciencias del Ejercicio y la Salud, 19(1), 1-27. Pregnancy is a progressive process involving hormonal, mechanical, physiological, and emotional changes in women that stimulates the musculoskeletal system to adapt constantly. These changes are usually identified through posture and the biomechanics of day-to-day movements. This study consists of a systematic review of the main alterations and adaptations during pregnancy, including articles from 2008 to 2018 that involved healthy pregnant women without previous musculoskeletal affections, with a single fetus and normal BMI, and any methods of study excluding case studies. Thirteen studies were identified which indicate evaluation of participants ages from 20 to 35 years during their three trimesters of pregnancy, as well as different study objectives. Posture in a pregnant woman shows an increase in the lumbar lordosis, thoracic curvature, and anterior tilt of the pelvis. The task of sitting and rising from a chair requires more control to complete the movement as well as increased execution time. Oscillation movement and ground reaction forces of the center of pressure of the body increase during standing posture, which results in a greater distance between the feet as a strategy to control the balance. Finally, gait biomechanics adapt to a slower speed, smaller step length, and less time with feet off the ground, but a wider step and support base. During pregnancy, women develop anatomic and mechanic adaptations in response to the progressive changes they experience.

Resumo Quesada Salazar, N. (2021). Alterações musculoesqueléticas e adaptações biomecânicas durante os trimestres de gravidez: uma revisão sistemática. PENSAR EN MOVIMIENTO: Revista de Ciencias del Ejercicio y la Salud, 19(1), 1-27. A gravidez é um processo progressivo que envolve mudanças de tipo hormonal, mecânico, fisiológico e emocional na mulher e que faz com que o sistema musculoesquelético se adapte constantemente. Essas mudanças tendem a ser identificadas por meio da postura e a biomecânica dos movimentos na vida diária. Nesta pesquisa foi realizada uma revisão sistemática para encontrar as principais alterações e adaptações durante a gravidez, incluindo artigos de 2008 a 2018, com mulheres gestantes saudáveis, com um único feto, sem alterações musculoesqueléticas prévias, com Índice de Massa Corporal (IMC) normal e qualquer metodologia de pesquisa, exceto estudos de caso. Foram identificados 13 estudos que registram avaliar as três etapas de gestação, com idades desde os 20 aos 35 anos, igualmente com diversos objetivos de pesquisa. A postura da mulher gestante apresenta um aumento de lordose lombar, curvatura toráxica e ângulo de inclinação anterior da pelve. A tarefa de sentar-se e levantar-se de uma cadeira exige maior controle do movimento, assim como de tempo de execução. A oscilação e as forças de reação do solo do Centro de Pressão corporal aumentam ao estar de pé, resultando em uma maior distância entre os pés, como estratégia de controle do equilíbrio. Finalmente, a biomecânica da marcha se adapta a uma menor velocidade, longitude de passo e fase de retirada dos pés do chão, com um aumento da largura do passo e uma maior base de apoio. Na gestação, a mulher desenvolve adaptações de tipo anatômicas e mecânicas como resposta para mudanças progressivas experimentadas.

Development and maintenance of tendons and ligaments.

Tendons and ligaments are fibrous connective tissues vital to the transmission of force and stabilization of the musculoskeletal system. Arising in precise regions of the embryo, tendons and ligaments share many properties and little is known about the molecular differences that differentiate them. Recent studies have revealed heterogeneity and plasticity within tendon and ligament cells, raising questions regarding the developmental mechanisms regulating tendon and ligament identity. Here, we discuss recent findings that contribute to our understanding of the mechanisms that establish and maintain tendon progenitors and their differentiated progeny in the head, trunk and limb. We also review the extent to which these findings are specific to certain anatomical regions and model organisms, and indicate which findings similarly apply to ligaments. Finally, we address current research regarding the cellular lineages that contribute to tendon and ligament repair, and to what extent their regulation is conserved within tendon and ligament development.

Diversification of the vertebrate limb: sequencing the events.

Naturalists leading up to the early 20th century were captivated by the diversity of limb form and function and described its development in a variety of species. The advent of discoveries in genetics followed by molecular biology led to focused efforts in few 'model' species, namely mouse and chicken, to understand conserved mechanisms of limb axis specification and development of the musculoskeletal system. 'Non-traditional' species largely fell by the wayside until their recent resurgence into the spotlight with advances in next-generation sequencing technologies (NGS). In this review, we focus on how the use of NGS has provided insights into the development, loss, and diversification of amniote limbs. Coupled with advances in chromatin interrogation techniques and functional tests in vivo, NGS is opening possibilities to understand the genetic mechanisms that govern the remarkable radiation of vertebrate limb form and function.

Single Cell Omics for Musculoskeletal Research.

PURPOSE OF REVIEW: The ability to analyze the molecular events occurring within individual cells as opposed to populations of cells is revolutionizing our understanding of musculoskeletal tissue development and disease. Single cell studies have the great potential of identifying cellular subpopulations that work in a synchronized fashion to regenerate and repair damaged tissues during normal homeostasis. In addition, such studies can elucidate how these processes break down in disease as well as identify cellular subpopulations that drive the disease. This review highlights three emerging technologies: single cell RNA sequencing (scRNA-seq), Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq), and Cytometry by Time-Of-Flight (CyTOF) mass cytometry. RECENT FINDINGS: Technological and bioinformatic tools to analyze the transcriptome, epigenome, and proteome at the individual cell level have advanced rapidly making data collection relatively easy; however, understanding how to access and interpret the data remains a challenge for many scientists. It is, therefore, of paramount significance to educate the musculoskeletal community on how single cell technologies can be used to answer research questions and advance translation. This article summarizes talks given during a workshop on "Single Cell Omics" at the 2020 annual meeting of the Orthopedic Research Society. Studies that applied scRNA-seq, ATAC-seq, and CyTOF mass cytometry to cartilage development and osteoarthritis are reviewed. This body of work shows how these cutting-edge tools can advance our understanding of the cellular heterogeneity and trajectories of lineage specification during development and disease.

Rheumatic diseases and associated factors in older adults: a Brazilian populationbased study / Doenças reumáticas e seus fatores associados em idosos: um estudo de base populacional brasileiro

INTRODUCTION: Rheumatic diseases have high occurrence in older adults, which may lead to a reduction in independence and quality of life. OBJECTIVE: To calculate prevalence and to identify factors associated with rheumatic diseases in older adults of the urban area of a municipality in Southern Brazil. METHODS: Cross-sectional population-based study, conducted in 2008 in the city of Bagé-RS, Brazil with older adults aged 60 years or over. The outcome was defined from the question "Has any doctor told you that you have rheumatism, arthritis or arthrosis?" Poisson regression was used for the crude and adjusted analysis. RESULTS: A total of 1,593 participants were interviewed. 27.3% (95% CI 25.0-29.5) reported having medical diagnosis of at least one of the rheumatic diseases studied. In the adjusted analysis, it was found that female sex (RP=2.86; 95% CI 2.28-3.59; p≤0.001), without schooling (RP=1.24; 95% CI 1.0-1.58; p=0.047), not living alone (RP=1.29; 95% CI 1.03-1.61; p=0.024), poor self-perception of health (PR=1.54; 95% CI 1.63-2.02; p=0.001), spinal problems (PR=1,96; 95% CI 1.67-2.31; p≤0.001), fall in the last year (PR=1.22; 95% CI 1.04-1.43; p=0.013), incapacity for instrumental activities of daily living (PR=1.20; 95% CI 1.02-1.41; p=0.028) and healthcare appointment in the last 3 months (PR=1.20; 95% CI 1.01-1.42; p=0.035) were associated with the presence of rheumatic diseases (rheumatism, arthritis and arthrosis). CONCLUSION: It is suggested that care of musculoskeletal problems of the spine should be increased, in order to reduce falls and functional disability in older adults, based on actions focused on the prevention of these problems.

INTRODUÇÃO: As doenças reumáticas têm alta ocorrência na população idosa, o que pode levar à redução da independência e da qualidade de vida. OBJETIVO: Determinar a prevalência e identificar os fatores associados às doenças reumáticas em idosos da zona urbana de um município do Sul do Brasil. MÉTODOS: Trata-se de estudo transversal de base populacional, realizado em 2008 na cidade de Bagé-RS, Brasil, com idosos com 60 anos ou mais. O desfecho foi definido a partir da pergunta "Algum médico já disse que você tem reumatismo, artrite ou artrose?" A regressão de Poisson foi usada para a análise bruta e ajustada. RESULTADOS: Foram entrevistados 1.593 idosos. Destes, 27,3% (IC 95% 25,0-29,5) relataram ter diagnóstico médico de pelo menos uma das doenças reumáticas estudadas. Na análise ajustada, constatou-se que o sexo feminino (RP=2,86; IC 95% 2,28-3,59; p≤0,001), sem escolaridade (RP=1,24; IC 95% 1,0-1,58; p=0,047), não vive sozinho (RP=1,29; IC 95% 1,03-1,61; p=0,024), autopercepção de saúde ruim (RP=1,54; IC 95% 1,63-2,02; p=0,001), problemas de coluna (RP=1,96; IC 95% 1,67-2,31; p≤0,001), queda no último ano (RP=1,22; IC 95% 1,04-1,43; p=0,013), presença de incapacidade para atividades instrumentais de vida diária (RP=1,20; IC 95% 1,02-1,41; p=0,028) e consulta médica nos últimos 3 meses (RP=1,20; IC 95% 1,01-1,42; p=0,035) estiveram associados à presença de doenças reumáticas (reumatismo, artrite e artrose). CONCLUSÃO: Sugere-se que os cuidados com os problemas musculoesqueléticos da coluna devem ser aumentados, a fim de reduzir as quedas e a incapacidade funcional em idosos, com base em ações voltadas para a prevenção desses problemas.

microRNA-31 regulates skeletogenesis by direct suppression of Eve and Wnt1.

microRNAs (miRNAs) play a critical role in a variety of biological processes, including embryogenesis and the physiological functions of cells. Evolutionarily conserved microRNA-31 (miR-31) has been found to be involved in cancer, bone formation, and lymphatic development. We previously discovered that, in the sea urchin, miR-31 knockdown (KD) embryos have shortened dorsoventral connecting rods, mispatterned skeletogenic primary mesenchyme cells (PMCs) and shifted and expanded Vegf3 expression domain. Vegf3 itself does not contain miR-31 binding sites; however, we identified its upstream regulators Eve and Wnt1 to be directly suppressed by miR-31. Removal of miR-31's suppression of Eve and Wnt1 resulted in skeletal and PMC patterning defects, similar to miR-31 KD phenotypes. Additionally, removal of miR-31's suppression of Eve and Wnt1 results in an expansion and anterior shift in expression of Veg1 ectodermal genes, including Vegf3 in the blastulae. This indicates that miR-31 indirectly regulates Vegf3 expression through directly suppressing Eve and Wnt1. Furthermore, removing miR-31 suppression of Eve is sufficient to cause skeletogenic defects, revealing a novel regulatory role of Eve in skeletogenesis and PMC patterning. Overall, this study provides a proposed molecular mechanism of miR-31's regulation of skeletogenesis and PMC patterning through its cross-regulation of a Wnt signaling ligand and a transcription factor of the endodermal and ectodermal gene regulatory network.

A developmental staging system and musculoskeletal development sequence of the common musk turtle (Sternotherus odoratus).

BACKGROUND: The extremely derived body plan of turtles has sparked a great interest in studying their developmental biology. Here, we describe the embryonic development of the Stinkpot, or common musk turtle (Sternotherus odoratus), a small aquatic turtle from the family Kinosternidae. RESULTS: We identify 20 distinct developmental stages, some comparable to stages described by previous studies on other turtles and some in between these, improving the resolution of the generalities of turtle development. We provide a detailed account of both the external morphology and skeletal development, as well as a general look at the early stages of muscular development until the attainment of the adult muscular anatomical pattern. CONCLUSIONS: Several potential skeletal and muscular apomorphies of turtles are identified or elaborated. The musk turtle, with its small size and hard-shelled egg, could become an important species for the study of turtle evolution and development, suitable for in ovo experimentation and late stage imaging of well-advanced anatomical features.

Development of the lamprey velum and implications for the evolution of the vertebrate jaw.

BACKGROUND: The vertebrate jaw is thought to have evolved through developmental modification of the mandibular arch. An extant jawless vertebrate, the lamprey, possesses a structure called "velum"-a mandibular arch derivative-in addition to the oral apparatus. This leads us to assess the velum's possible contribution to the evolution of jaws. RESULTS: The velar muscles develop from progenitor cells distinct from those from which the oral muscles develop. In addition, the oral and velar regions originate from the different sub-population of the trigeminal neural crest cells (NCCs): the former region receives NCCs from the midbrain, whereas the latter region receives NCCs from the anterior hindbrain. The expression of patterning genes (eg, DlxA and MsxA) is activated at a later developmental stage in the velum compared to the oral region, and more importantly, in different cells from those in the oral region. CONCLUSION: The lamprey mandibular arch consists of two developmental units: the anterior oral unit and the posterior velar unit. Because structural elements of the lamprey velum may be homologous to the jaw, the evolution of vertebrate jaws may have occurred by the velum being released from its functional roles in feeding or respiration in jawless vertebrates.

Role of noncanonical Wnt ligands and Ror-family receptor tyrosine kinases in the development, regeneration, and diseases of the musculoskeletal system.

The Ror-family receptor tyrosine kinases (RTKs), consisting of Ror1 and Ror2, play crucial roles in morphogenesis and formation of various tissues/organs, including the bones and skeletal muscles, the so-called musculoskeletal system, during embryonic development, by acting as receptors or coreceptors for a noncanonical Wnt protein Wnt5a. Furthermore, several lines of evidence have indicated that Ror1 and/or Ror2 play critical roles in the regeneration and maintenance of the musculoskeletal system in adults. Considering the anatomical and functional relationship between the skeleton and skeletal muscles, their structural and functional association might be tightly regulated during their embryonic development, development after birth, and their regeneration after injury in adults. Importantly, in addition to their congenital anomalies, much attention has been paid onto the age-related disorders of the musculoskeletal system, including osteopenia and sarcopenia, which affect severely the quality of life. In this article, we overview recent advances in our understanding of the roles of Ror1- and/or Ror2-mediated signaling in the embryonic development, regeneration in adults, and congenital and age-related disorders of the musculoskeletal system and discuss possible therapeutic approaches to locomotive syndromes by modulating Ror1- and/or Ror2-mediated signaling.

The quest for substrates and binding partners: A critical barrier for understanding the role of ADAMTS proteases in musculoskeletal development and disease.

Secreted ADAMTS metalloproteases are involved in the sculpting, remodeling, and erosion of connective tissues throughout the body, including in the musculoskeletal system. ADAMTS proteases contribute to musculoskeletal development, pathological tissue destruction, and are mutated in congenital musculoskeletal disorders. Examples include versican cleavage by ADAMTS9 which is required for interdigital web regression during limb development, ADAMTS5-mediated aggrecan degradation in osteoarthritis resulting in joint erosion, and mutations in ADAMTS10 or ADAMTS17 that cause Weill-Marchesani syndrome, a short stature syndrome with bone, joint, muscle, cardiac, and eye involvement. Since the function of ADAMTS proteases and proteases in general is primarily defined by the molecular consequences of proteolysis of their respective substrates, it is paramount to identify all physiological substrates for each individual ADAMTS protease. Here, we review the current knowledge of ADAMTS proteases and their involvement in musculoskeletal development and disease, focusing on some of their known physiological substrates and the consequences of substrate cleavage. We further emphasize the critical need for the identification and validation of novel ADAMTS substrates and binding partners by describing the principles of mass spectrometry-based approaches and by emphasizing strategies that need to be considered for validating the physiological relevance for ADAMTS-mediated proteolysis of novel putative substrates.

The molecular mechanisms of probiotic strains in improving ageing bone and muscle of d-galactose-induced ageing rats.

AIM: The aim of this study was to evaluate the molecular mechanisms of Lactobacillus strains in improving ageing of the musculoskeletal system. METHODS AND RESULTS: The anti-ageing mechanism of three probiotics strains Lactobacillus fermentum DR9, Lactobacillus paracasei OFS 0291 and L. helveticus OFS 1515 were evaluated on gastrocnemius muscle and tibia of d-galactose-induced ageing rats. Upon senescence induction, aged rats demonstrated reduced antioxidative genes CAT and SOD expression in both bone and muscle compared to the young rats (P < 0·05). Strain L. fermentum DR9 demonstrated improved expression of SOD in bone and muscle compared to the aged rats (P < 0·05). In the evaluation of myogenesis-related genes, L. paracasei OFS 0291 and L. fermentum DR9 increased the mRNA expression of IGF-1; L. helveticus OFS 1515 and L. fermentum DR9 reduced the expression of MyoD, in contrast to the aged controls (P < 0·05). Protective effects of L. fermentum DR9 on ageing muscle were believed to be contributed by increased AMPK-α2 expression. Among the osteoclastogenesis genes studied, TNF-α expression was highly elevated in tibia of aged rats, while all three probiotics strains ameliorated the expression. Lactobacillus fermentum DR9 also reduced the expression of IL-6 and TRAP in tibia when compared to the aged rats (P < 0·05). All probiotics treatment resulted in declined proinflammatory cytokines IL-1ß in muscle and bone. CONCLUSIONS: Lactobacillus fermentum DR9 appeared to be the strongest strain in modulation of musculoskeletal health during ageing. SIGNIFICANCE AND IMPACT OF THE STUDY: The study demonstrated the protective effects of the bacteria on muscle and bone through antioxidative and anti-inflammatory actions. Therefore, L. fermentum DR9 may serve as a promising targeted anti-ageing therapy.