Vertebral Development Research Articles

Analysis of vertebrotomy treatment in children with congenital scoliosis with unsegmented rod and rib synostosis

BACKGROUND: Congenital anomalies of vertebral development account for 2%–11% of cases in the general structure of nosologies that cause spinal deformity. An unsegmented rod (unilateral violation of vertebral segmentation) is attributed to a prognostically unfavorable malformation. Rib synostosis causes the development of thoracic insufficiency syndrome. AIM: To analyze the results of treatment of children with congenital scoliosis caused by an unsegmented rod and rib synostosis by vertebrotomy. MATERIALS AND METHODS: This cohort, retrospective, monocenter study evaluated the treatment results of 55 patients. The patients were divided into two groups: group 1, children aged 2–8 years, the scope of intervention was wedge-shaped osteotomy of a non-segmented rod at the apex of the deformity, and group 2, children aged 8–18 years, the scope of intervention was wedge-shaped osteotomy at the apex of the deformity and two linear osteotomies of a non-segmented rod in the cranial and caudal directions. Clinical, radiological, and statistical research methods were used. RESULTS: Significant correction of scoliosis was achieved in 65.5% of patients aged 2–7 years (group 1) and 56.3% in children aged 8–18 years (group 2). Hypokyphosis of the thoracic spine was observed in the patients. The percentage of correction of kyphosis was 21.1% in group 1 and 19.1% in group 2. Lung volume increased by 27.9% (p = 0.01776) in group 1, and lung volume on the concave side increased by 23.5% (p = 0.04975) and on the convex side by 29.6% (p = 0.01073). Improvement in the overall respiratory impedance reached 47.3% (p 0.05). In group 2, a insignificant increase was found in VVC by 12.6% (p = 0.3509) and FEV1 by 8.7% of the initial (p = 0.1534), as well as an increase in total lung volume of 13.3% (p = 0.1527) and the contribution of the lung along the concave side of 18.8% (p = 0.1535), and the lung along the convex side was 8.4% (p = 0.169), indicating no significant impact on lung development and function. CONCLUSIONS: In children with spinal deformity caused by a non-segmented rod with normal respiratory function, vertebrotomy at the apex of the deformity with subsequent correction and stabilization of the spinal deformity is recommended. Performing simultaneous multilevel osteotomies of a non-segmented rod allows for significant correction of rigid spinal deformity.

Impaired Skeletal Development by Disruption of Presenilin-1 in Pigs and Generation of Novel Pig Models for Alzheimer's Disease.

Presenilin 1 (PSEN1) is one of the genes linked to the prevalence of early onset Alzheimer's disease. In mice, inactivation of Psen1 leads to developmental defects, including vertebral malformation and neural development. However, little is known about the role of PSEN1 during the development in other species. To investigate the role of PSEN1 in vertebral development and the pathogenic mechanism of neurodegeneration using a pig model. CRISPR/Cas9 system was used to generate pigs with different mutations flanking exon 9 of PSEN1, including those with a deleted exon 9 (Δexon9). Vertebral malformations in PSEN1 mutant pigs were examined by X-ray, micro-CT and micro-MRI. Neuronal cells from the brains of PSEN1 mutant pigs were analyzed by immunoflourescence, followed by image analysis including morphometric evaluation via image J and 3D reconstruction. Pigs with a PSEN1 null mutation (Δexon9-12) died shortly after birth and had significant axial skeletal defects, whereas pigs carrying at least one Δexon9 allele developed normally and remained healthy. Effects of the null mutation on abnormal skeletal development were also observed in fetuses at day 40 of gestation. Abnormal distribution of astrocytes and microglia in the brain was detected in two PSEN1 mutant pigs examined compared to age-matched control pigs. The founder pigs were bred to establish and age PSEN1ΔE9/+ pigs to study their relevance to clinical Alzheimer's diseases. PSEN1 has a critical role for normal vertebral development and PSEN1 mutant pigs serves as novel resources to study Alzheimer's disease.

Endochondral Ossification for Spinal Fusion: A Novel Perspective from Biological Mechanisms to Clinical Applications.

Degenerative scoliosis (DS), encompassing conditions like spondylolisthesis and spinal stenosis, is a common type of spinal deformity. Lumbar interbody fusion (LIF) stands as a conventional surgical intervention for this ailment, aiming at decompression, restoration of intervertebral height, and stabilization of motion segments. Despite its widespread use, the precise mechanism underlying spinal fusion remains elusive. In this review, our focus lies on endochondral ossification for spinal fusion, a process involving vertebral development and bone healing. Endochondral ossification is the key step for the successful vertebral fusion. Endochondral ossification can persist in hypoxic conditions and promote the parallel development of angiogenesis and osteogenesis, which corresponds to the fusion process of new bone formation in the hypoxic region between the vertebrae. The ideal material for interbody fusion cages should have the following characteristics: (1) Good biocompatibility; (2) Stable chemical properties; (3) Biomechanical properties similar to bone tissue; (4) Promotion of bone fusion; (5) Favorable for imaging observation; (6) Biodegradability. Utilizing cartilage-derived bone-like constructs holds promise in promoting bony fusion post-operation, thus warranting exploration in the context of spinal fusion procedures.

Application of neurophysiological studies for diagnosis and justification of neurosurgical treatment of kyphotic deformity due to the congenital anomaly of the spine

The results of a comprehensive clinical, radiological and neurophysiological study were analyzed in patients with kyphotic deformity of the thoracic and lumbar spine due to a congenital anomaly of vertebral development in the dynamics of surgical treatment. It has been established that congenital kyphotic spinal deformity is accompanied by vertebromedullary conflict with a high risk of the occurrence and/or worsening of spinal neurological disorders. The study of the data obtained made it possible to evaluate deformation lesions of the spine from the standpoint of qualitative and quantitative severity of pathological changes in the conduction function in the system of nervous tracts of the spinal cord, which was an objective argument in justifying the indications for surgical correction and its methodological implementation, as well as an important neurophysiological criterion for subsequent dynamic monitoring of clinical conditions of a patient.It was found that the surgical treatment allowed us to improve and subsequently stabilize the functional state of the spinal cord as a consequence of the achieved significant correction of congenital kyphotic spinal deformity.

Embryonic Thyroid Hormone Insufficiency Causes Structural Anomalies in the Embryo of Domestic Chick, Gallus domesticus.

Thyroid hormone (TH) is essential for growth and development, yet its specific role during embryogenesis remains incompletely understood. This study investigates the impact of TH deficiency, induced by thiourea, a known inhibitor of thyroid peroxidase (TPO), on the development of domestic chicks. Thiourea was administered before thyroid gland formation, and its presence in treated embryos was confirmed through liquid chromatography-mass spectrometry. In silico docking revealed a strong interaction between thiourea and the CCP-like domain of TPO, which was corroborated by TPO activity assays showing reduced enzyme function. This reduction in enzyme activity led to lower embryonic TH levels and increased thyroid-stimulating hormone (TSH) secretion. Morphological analysis of newly hatched chicks revealed significant structural anomalies, particularly in lateral plate mesoderm-derived structures, including omphalocele, limb deformities, anophthalmia and craniofacial defects. Alcian blue and Alizarin red staining demonstrated reduced ossification in ribs and forelimbs, while histological analysis showed incomplete abdominal wall closure and abnormal vertebral column development. Haematological profiling of TH-deficient newly hatched chicks revealed significantly lower blood cell counts, highlighting TH's critical role in haematopoiesis. These findings emphasise the multifaceted role of TH in embryonic development, with potential implications for understanding congenital hypothyroidism and its developmental impacts, especially in regions with limited healthcare access.

Core planar cell polarity genes VANGL1 and VANGL2 in predisposition to congenital vertebral malformations

Congenital scoliosis (CS), affecting approximately 0.5 to 1 in 1,000 live births, is commonly caused by congenital vertebral malformations (CVMs) arising from aberrant somitogenesis or somite differentiation. While Wnt/ß-catenin signaling has been implicated in somite development, the function of Wnt/planar cell polarity (Wnt/PCP) signaling in this process remains unclear. Here, we investigated the role of Vangl1 and Vangl2 in vertebral development and found that their deletion causes vertebral anomalies resembling human CVMs. Analysis of exome sequencing data from multiethnic CS patients revealed a number of rare and deleterious variants in VANGL1 and VANGL2, many of which exhibited loss-of-function and dominant-negative effects. Zebrafish models confirmed the pathogenicity of these variants. Furthermore, we found that Vangl1 knock-in (p.R258H) mice exhibited vertebral malformations in a Vangl gene dose- and environment-dependent manner. Our findings highlight critical roles for PCP signaling in vertebral development and predisposition to CVMs in CS patients, providing insights into the molecular mechanisms underlying this disorder.

Nanoscale myelinogenesis image in developing brain via super-resolution nanoscopy by near-infrared emissive curcumin-BODIPY derivatives

Understanding the intricate nanoscale architecture of neuronal myelin during central nervous system development is of utmost importance. However, current visualization methods heavily rely on electron microscopy or indirect fluorescent method, lacking direct and real-time imaging capabilities. Here, we introduce a breakthrough near-infrared emissive curcumin-BODIPY derivative (MyL-1) that enables direct visualization of myelin structure in brain tissues. The remarkable compatibility of MyL-1 with stimulated emission depletion nanoscopy allows for unprecedented super-resolution imaging of myelin ultrastructure. Through this innovative approach, we comprehensively characterize the nanoscale myelinogenesis in three dimensions over the course of brain development, spanning from infancy to adulthood in mouse models. Moreover, we investigate the correlation between myelin substances and Myelin Basic Protein (MBP), shedding light on the essential role of MBP in facilitating myelinogenesis during vertebral development. This novel material, MyL-1, opens up new avenues for studying and understanding the intricate process of myelinogenesis in a direct and non-invasive manner, paving the way for further advancements in the field of nanoscale neuroimaging.Graphical

Advancements in Genetic Marker Exploration for Livestock Vertebral Traits with a Focus on China.

In livestock breeding, the number of vertebrae has gained significant attention due to its impact on carcass quality and quantity. Variations in vertebral traits have been observed across different animal species and breeds, with a strong correlation to growth and meat production. Furthermore, vertebral traits are classified as quantitative characteristics. Molecular marker techniques, such as marker-assisted selection (MAS), have emerged as efficient tools to identify genetic markers associated with vertebral traits. In the current review, we highlight some key potential genes and their polymorphisms that play pivotal roles in controlling vertebral traits (development, length, and number) in various livestock species, including pigs, donkeys, and sheep. Specific genetic variants within these genes have been linked to vertebral development, number, and length, offering valuable insights into the genetic mechanisms governing vertebral traits. This knowledge has significant implications for selective breeding strategies to enhance structural characteristics and meat quantity and quality in livestock, ultimately improving the efficiency and quality of the animal husbandry industry.

Clinical outcomes and spinal growth after posterior hemivertebra resection and short segment fusion in children.

To evaluate the corrective effect of posterior hemivertebra resection and short-segment fusion surgery on pediatric patients and to assess the impact of short-segment fixation surgery on vertebral development during follow-up, a retrospective analysis was performed on 28 pediatric patients who underwent posterior hemivertebra resection surgery. The corrective effect was evaluated by comparing indicators such as segmental scoliosis Cobb angle, upper and lower compensatory curves and trunk balance at different time points. Meanwhile, the vertebral and spinal canal diameters of instrumented vertebrae and adjacent noninstrumented vertebrae were measured and compared to assess vertebral and spinal canal development. The correction rate of segmental scoliosis was 72.2%. The estimated mean vertebral volume of the instrumented vertebra was slightly lower than that of the unfused segment at the final follow-up, but the difference was not statistically significant. The growth rate of the spinal canal during follow-up was much smaller than that of the vertebral body. In summary, internal fixation at a young age shows no significant inhibitory effects on spinal development within the fusion segment. Posterior hemivertebra resection and short-segment fusion surgery are safe and effective.

Combined Transcriptomics and Metabolomics Identify Regulatory Mechanisms of Porcine Vertebral Chondrocyte Development In Vitro.

Porcine body length is closely related to meat production, growth, and reproductive performance, thus playing a key role in the profitability of the pork industry. Cartilage development is critical to longitudinal elongation of individual vertebrae. This study isolated primary porcine vertebral chondrocytes (PVCs) to clarify the complex mechanisms of elongation. We used transcriptome and target energy metabolome technologies to confirm crucial genes and metabolites in primary PVCs at different differentiation stages (0, 4, 8, and 12 days). Pairwise comparisons of the four stages identified 4566 differentially expressed genes (DEGs). Time-series gene cluster and functional analyses of these DEGs revealed four clusters related to metabolic processes, cartilage development, vascular development, and cell cycle regulation. We constructed a transcriptional regulatory network determining chondrocyte maturation. The network indicated that significantly enriched transcription factor (TF) families, including zf-C2H2, homeobox, TF_bZIP, and RHD, are important in cell cycle and differentiation processes. Further, dynamic network biomarker (DNB) analysis revealed that day 4 was the tipping point for chondrocyte development, consistent with morphological and metabolic changes. We found 24 DNB DEGs, including the TFs NFATC2 and SP7. Targeted energy metabolome analysis showed that most metabolites were elevated throughout chondrocyte development; notably, 16 differentially regulated metabolites (DRMs) were increased at three time points after cell differentiation. In conclusion, integrated metabolome and transcriptome analyses highlighted the importance of amino acid biosynthesis in chondrocyte development, with coordinated regulation of DEGs and DRMs promoting PVC differentiation via glucose oxidation. These findings reveal the regulatory mechanisms underlying PVC development and provide an important theoretical reference for improving pork production.

Decision tree analysis for age estimation in living individuals: integrating cervical and dental radiographic evaluations within a South African population.

Age estimation in living individuals around the age of 18years is medico-legally important in undocumented migrant cases and in countries like South Africa where many individuals are devoid of identification documents. Establishing whether an individual is younger than 18years largely influences the legal procedure that should be followed in dealing with an undocumented individual. The aim of this study was to combine dental third molar and anterior inferior apophysis ossification data for purposes of age estimation, by applying a decision tree analysis. A sample comprising of 871 black South African individuals (n = 446 males, 425 = females) with ages ranging between 15 and 24years was analyzed using panoramic and cephalometric radiographs. Variables related to the left upper and lower third molars and cervical vertebral ring apophysis ossification of C2, C3, and C4 vertebrae analyzed in previous studies were combined in a multifactorial approach. The data were analyzed using a pruned decision tree function for classification. Male and female groups were handled separately as a statistically significant difference was found between the sexes in the original studies. A test sample of 30 individuals was used to determine if this approach could be used with confidence in estimating age of living individuals. The outcomes obtained from the test sample indicated a close correlation between the actual ages (in years and months) and the predicted ages (in years only), demonstrating an average age difference of 0.47years between the corresponding values. This method showed that the application of decision tree analysis using the combination of third molar and cervical vertebral development is usable and potentially valuable in this application.

Efficacy and risk of osteonecrosis of the jaw for pamidronate, zoledronic acid, and denosumab in comparison to alendronate in multiple myeloma patients

Background Approximately 70% of multiple myeloma patients develop pathologic fractures. Osteoclast inhibitors can provide reduction in vertebral fractures with an increased risk of osteonecrosis of the jaw (ONJ). ONJ associated with currently used osteoclast inhibitors causes significant morbidity, often from delayed diagnosis and ineffective treatment. Methods The TriNetX Diamond Network was used to create patient cohorts for each medication: alendronate, pamidronate, zoledronic acid, and denosumab. All patients had a diagnosis of multiple myeloma as identified by International Classification of Disease–10 (ICD-10) code C90.0. Pamidronate, zoledronic acid, and denosumab were each compared to alendronate for 5-year incidence of pathologic vertebral fracture (ICD-10 M48.50XA) and development of ONJ. Results The 5-year risk of pathologic vertebral fracture was not statistically different between alendronate versus pamidronate, zoledronic acid, and denosumab. However, the 5-year risk of ONJ was significantly higher for both zoledronic acid and denosumab (relative risk 4.85 and 2.9, respectively). Conclusion This study shows that fracture reduction risk is comparable for all four treatments in multiple myeloma patients, but ONJ risk is lowest for alendronate and pamidronate. Overall, these data support the continued use of pamidronate and alendronate in multiple myeloma patients.

Epichordal vertebral column formation in Xenopus laevis.

Although Xenopus Laevis is the most widely used model amphibian, skeletal development of its vertebral column has not been well illustrated so far. The mode of vertebral column development in anurans has been classified into two modes: perichordal and epichordal. Xenopus vertebral column formation is believed to follow the epichordal mode, but this aspect has been underemphasized, and illustrative examples are currently unavailable to the scientific community. This study documents the entire process of vertebral column formation in X. laevis, from the initial neural arch formation to the completion of metamorphosis. These images reveal that the neural arch arises from the dorsal lamina and lateral pedicle primordia, with no strict adherence to an anteroposterior sequence. Unlike other species, Xenopus centrum primordia exclusively form at the expanded ventral margins of neural arches, rather than from the cartilaginous layer surrounding the notochord. These paired centrum primordia then fuse at the ventral midline, dorsal to the notochord, and subsequently the notochord degenerates. This mode of centrum formation differs from the traditional epichordal mode, indicating that Xenopus might have lost the ability to form a cartilaginous layer around the notochord. Instead, the neural arch's ventral margin appears to have evolved to incorporate centrum precursor cells at its base, thereby forming a centrum-like structure compensating for the absence of a true centrum. It is widely accepted that postsacral vertebrae lack centra, only possessing neural arches, and eventually fuse with the hypochord to form the urostyle. However, we have shown that the paired ventral ends of the postsacral vertebrae also fuse at the midline to form a centrum-like structure. This process might extend to the trunk region during centrum formation. In addition to these findings, we offer evolutionary insights into the reasons why Xenopus retains centrum primordia at the base of neural arches.

Vertebral pattern and morphology is determined during embryonic segmentation.

The segmented nature of the adult vertebral column is based on segmentation of the paraxial mesoderm during early embryogenesis. Disruptions to embryonic segmentation, whether caused by genetic lesions or environmental stress, result in adult vertebral pathologies. However, the mechanisms linking embryonic segmentation and the details of adult vertebral morphology are poorly understood. We induced border defects using two approaches in zebrafish: heat stress and misregulation of embryonic segmentation genes tbx6, mesp-ba, and ripply1. We assayed vertebral length, regularity, and polarity using microscopic and radiological imaging. In population studies, we find a correlation between specific embryonic border defects and specific vertebral defects, and within individual fish, we trace specific adult vertebral defects to specific embryonic border defects. Our data reveal that transient disruptions of embryonic segment border formation led to significant vertebral anomalies that persist through adulthood. The spacing of embryonic borders controls the length of the vertebra. The positions of embryonic borders control the positions of ribs and arches. Embryonic borders underlie fusions and divisions between adjacent spines and ribs. These data suggest that segment borders have a dominant role in vertebral development.

COL11A2 as a candidate gene for vertebral malformations and congenital scoliosis.

Human vertebral malformations (VMs) have an estimated incidence of 1/2000 and are associated with significant health problems including congenital scoliosis (CS) and recurrent organ system malformation syndromes such as VACTERL (vertebral anomalies; anal abnormalities; cardiac abnormalities; tracheo-esophageal fistula; renal anomalies; limb anomalies). The genetic cause for the vast majority of VMs are unknown. In a CS/VM patient cohort, three COL11A2 variants (R130W, R1407L and R1413H) were identified in two patients with cervical VM. A third patient with a T9 hemivertebra and the R130W variant was identified from a separate study. These substitutions are predicted to be damaging to protein function, and R130 and R1407 residues are conserved in zebrafish Col11a2. To determine the role for COL11A2 in vertebral development, CRISPR/Cas9 was used to create a nonsense mutation (col11a2L642*) as well as a full gene locus deletion (col11a2del) in zebrafish. Both col11a2L642*/L642* and col11a2del/del mutant zebrafish exhibit vertebral fusions in the caudal spine, which form due to mineralization across intervertebral segments. To determine the functional consequence of VM-associated variants, we assayed their ability to suppress col11a2del VM phenotypes following transgenic expression within the developing spine. While wildtype col11a2 expression suppresses fusions in col11a2del/+ and col11a2del/del backgrounds, patient missense variant-bearing col11a2 failed to rescue the loss-of-function phenotype in these animals. These results highlight an essential role for COL11A2 in vertebral development and support a pathogenic role for two missense variants in CS.

Skeletal, dental, and sexual maturation as an indicator of pubertal growth spurt.

The aims of this study were to determine the skeletal, dental, and sexual maturation stages of individuals at the peak of the pubertal growth spurt and to analyze the correlations between these parameters. The study included 98 patients, 49 females (mean chronological age 12.05 ± 0.96 years) and 49 males (mean chronological age: 13.18 ± 0.86 years), in the MP3cap stage. Skeletal maturation stages were determined using the cervical vertebral maturation (CVM) method on lateral cephalometric radiographs. The Demirjian index was used to determine dental maturation stages and dental ages on panoramic radiographs. The sexual maturation of the patients was evaluated in the pediatric endocrinology clinic by a pediatrician according to the Tanner stages. The frequencies of the variables were determined, and the Spearman rank correlation coefficients were used to analyze the correlations between the variables. It was determined that the cervical vertebral maturation stage was CS3 in 81.6% (n = 40) of both female and male patients, and 81.6% of the female and 89.8% of the male patients were in stage G in terms of mandibular second molar tooth development. According to the Tanner pubic hair staging, 73.5% of the male and 51.0% of the female patients were in Stage 3. A significant correlation was found between the cervical vertebra stages and mandibular second molar tooth development stages in both sexes and between the cervical vertebra and Tanner pubic hair stages only among the male patients (r = 0.357; p < .05). There was also a significant and strong correlation between the Tanner pubic hair stages and breast development stages (r = 0.715; p < .05). Cervical vertebral development in the CS3 stage and mandibular molar tooth development in the G stage can be considered the peak of the pubertal growth spurt. Tanner Stage 3 marks the peak of the pubertal growth spurt in males.

The effect of pedicle screw instrumentation at a young age on upper thoracic vertebra and canal development

BACKGROUND CONTEXTPedicle screws are widely used in spinal surgeries. Pedicle screw fixation has shown better clinical effects than other techniques by providing steady fixation from the posterior arch to the vertebral body. However, there are several concerns about the impact of pedicle screw instrumentation insertion on vertebral development in young children, including early closure of the neurocentral cartilage (NCC). The effect of pedicle screw insertion in an early age on further growth of the upper thoracic spine is still unclear. PURPOSEThis study aimed to evaluate the impact of pedicle screw insertion on further growth of the upper thoracic vertebra and spinal canal. STUDY DESIGNA retrospective case study. PATIENT SAMPLETwenty-eight patients. OUTCOME MEASUREMENTSX-ray and CT parameters including length, height and area of the vertebrae and spinal canal were manually measured. METHODSTwenty-eight patients who underwent pedicle screw fixation (T1-T6) before the age of 5 years from March 2005 to August 2019 at Peking Union Medical College Hospital were recruited, and records were retrospectively reviewed. Vertebral body and spinal canal parameters were measured at instrumented and adjacent noninstrumented levels and compared using statistical methods. RESULTSNinety-seven segments met the inclusion criteria (average age at instrumentation 44.57 months, range from 23–60 months). Thirty-nine segments had no screws, and 58 had at least one screw. There was no significant difference between the preoperative and final follow-up values of the measurement of vertebral body parameters. No significant difference was observed between the growth rates in levels with or without screws in pedicle length, vertebral body diameter, or spinal canal parameters. CONCLUSIONPedicle screw instrumentation in the upper thoracic spine does not cause a negative effect on the development of the vertebral body and spinal canal in children younger than 5 years old.

Direct BMP signaling to chordoblasts is required for the initiation of segmented notochord sheath mineralization in zebrafish vertebral column development.

The vertebral column, with the centra as its iteratively arranged building blocks, represents the anatomical key feature of the vertebrate phylum. In contrast to amniotes, where vertebrae are formed from chondrocytes and osteoblasts deriving from the segmentally organized neural crest or paraxial sclerotome, teleost vertebral column development is initiated by chordoblasts of the primarily unsegmented axial notochord, while sclerotomal cells only contribute to later steps of vertebrae formation. Yet, for both mammalian and teleostean model systems, unrestricted signaling by Bone Morphogenetic Proteins (BMPs) or retinoic acid (RA) has been reported to cause fusions of vertebral elements, while the interplay of the two signaling processes and their exact cellular targets remain largely unknown. Here, we address this interplay in zebrafish, identifying BMPs as potent and indispensable factors that, as formerly shown for RA, directly signal to notochord epithelial cells/chordoblasts to promote entpd5a expression and thereby metameric notochord sheath mineralization. In contrast to RA, however, which promotes sheath mineralization at the expense of further collagen secretion and sheath formation, BMP defines an earlier transitory stage of chordoblasts, characterized by sustained matrix production/col2a1 expression and concomitant matrix mineralization/entpd5a expression. BMP-RA epistasis analyses further indicate that RA can only affect chordoblasts and their further progression to merely mineralizing cells after they have received BMP signals to enter the transitory col2a1/entpd5a double-positive stage. This way, both signals ensure consecutively for proper mineralization of the notochord sheath within segmented sections along its anteroposterior axis. Our work sheds further light onto the molecular mechanisms that orchestrate early steps of vertebral column segmentation in teleosts. Similarities and differences to BMP's working mechanisms during mammalian vertebral column formation and the pathomechanisms underlying human bone diseases such as Fibrodysplasia Ossificans Progressiva (FOP) caused by constitutively active BMP signaling are discussed.

Sf3b4 regulates chromatin remodeler splicing and Hox expression

SF3B proteins form a heptameric complex in the U2 small nuclear ribonucleoprotein, essential for pre-mRNA splicing. Heterozygous pathogenic variants in human SF3B4 are associated with head, face, limb, and vertebrae defects. Using the CRISPR/Cas9 system, we generated mice with constitutive heterozygous deletion of Sf3b4 and showed that mutant embryos have abnormal vertebral development. Vertebrae abnormalities were accompanied by changes in levels and expression pattern of Hox genes in the somites. RNA sequencing analysis of whole embryos and somites of Sf3b4 mutant and control litter mates revealed increased expression of other Sf3b4 genes. However, the mutants exhibited few differentially expressed genes and a large number of transcripts with differential splicing events (DSE), predominantly increased exon skipping and intron retention. Transcripts with increased DSE included several genes involved in chromatin remodeling that are known to regulate Hox expression. Our study confirms that Sf3b4 is required for normal vertebrae development and shows, for the first time, that like Sf3b1, Sf3b4 also regulates Hox expression. We propose that abnormal splicing of chromatin remodelers is primarily responsible for vertebral defects found in Sf3b4 heterozygous mutant embryos.

Investigation of the Effects of Some Cardiovascular Drugs on Angiogenesis by Transgenic Zebrafish.

Angiogenesis contributes to the pathophysiology of cardiovascular disease (CVD). Some cardiovascular drugs used in the treatment of CVD have an effect on the process of angiogenesis. Transgenic Tg (flk1: EGFP) zebrafish embryos were used to identify the effects of some cardiovascular drugs on angiogenesis during vertebral development in vivo. Zebrafish embryos at a one-cell stage or two-cell stage were cultured with embryo medium containing cardiovascular drugs at a final solvent concentration of 0.5% (V/V) dimethyl sulfoxide (DMSO) for 24 hours in 24-well plates. We found that 6 drugs including isosorbide mononitrate, amlodipine, bisoprolol fumarate, carvedilol, irbesartan, and rosuvastatin calcium may affect angiogenesis by vascular endothelial growth factor (VEGF) signaling pathway. These new findings of some cardiovascular drugs should improve the treatment of cardiovascular diseases.