13 research outputs found
Retinoic acid mediates a premature osteoblast-to- (pre)osteocyte transition, induces osteoclast differentiation, and disturbs skull and fin rays dermal bone homeostasis in the zebrafish (Danio rerio)
Retinoic acid-induced premature osteoblast-to-preosteocyte transitioning has multiple effects on calvarial development
We have previously shown that, in human and zebrafish, hypomorphic mutations of the gene encoding the retinoic acid (RA)-metabolizing enzyme Cyp26b1 result in coronal craniosynostosis, caused by an RA-induced premature transitioning of suture osteoblasts to preosteocytes, inducing ectopic mineralization of the suture's osteoid matrix. In addition, we showed that human CYP26B1 null patients have more severe and seemingly opposite skull defects, characterized by smaller and fragmented calvaria, but the cellular basis of these defects remained largely unclear. Here, by treating juvenile zebrafish with exogenous RA or a chemical Cyp26 inhibitor in the presence or absence of osteogenic cells or bone-resorbing osteoclasts, we demonstrate that both reduced calvarial size and calvarial fragmentation are also caused by RA-induced premature osteoblast-to-preosteocyte transitioning. During calvarial growth, the resulting osteoblast deprival leads to decreased osteoid production and thereby smaller and thinner calvaria, whereas calvarial fragmentation is caused by increased osteoclast stimulation through the gained preosteocytes. Together, our data demonstrate that RA-induced osteoblast-to-preosteocyte transitioning has multiple effects on developing bone in Cyp26b1 mutants, ranging from gain to loss of bone, depending on the allelic strength, the developmental stage and the cellular context
Focused exploration for cooperative robotic watercraft
Environmental monitoring is one of the main societal challenge of the last century. In this work, we focus on a water monitoring system, based on Cooperative Robotic Watercrafts (CRW). A crucial aspect for the CRW is the high level of autonomy of the platforms, which can be controlled by few human operators that provide high level instructions to the system. The contribution of this paper is to propose a new method for cooperative exploration, providing an approach to collect relevant information while minimizing costs. Results show that the proposed approach provides a promising method for monitoring water bodies when there is a-priori information on interesting range of values for the data to be acquired
Diagnosis of Sickle Cell Disease and HBB Haplotyping in the Era of Personalized Medicine: Role of Next Generation Sequencing
Hemoglobin genotype and HBB haplotype are established genetic factors that modify the clinical phenotype in sickle cell disease (SCD). Current methods of establishing these two factors are cumbersome and/or prone to errors. The throughput capability of next generation sequencing (NGS) makes it ideal for simultaneous interrogation of the many genes of interest in SCD. This study was designed to confirm the diagnosis in patients with HbSS and Sβ-thalassemia, identify any ß-thal mutations and simultaneously determine the ßS HBB haplotype. Illumina Ampliseq custom DNA panel was used to genotype the DNA samples. Haplotyping was based on the alleles on five haplotype-specific SNPs. The patients studied included 159 HbSS patients and 68 Sβ-thal patients, previously diagnosed using high performance liquid chromatography (HPLC). There was considerable discordance between HPLC and NGS results, giving a false +ve rate of 20.5% with a sensitivity of 79% for the identification of Sβthal. Arab/India haplotype was found in 81.5% of βS chromosomes, while the two most common, of the 13 β-thal mutations detected, were IVS-1 del25 and IVS-II-1 (G>A). NGS is very versatile and can be deployed to simultaneously screen multiple gene loci for modifying polymorphisms, to afford personalized, evidence-based counselling and early intervention
Unique Polymorphisms at BCL11A, HBS1L-MYB and HBB Loci Associated with HbF in Kuwaiti Patients with Sickle Cell Disease
Patients with sickle cell disease (SCD) in Kuwait have elevated HbF levels ranging from ~10–44%; however, the modulating factors are unclear. We investigated the association of single nucleotide polymorphisms (SNPs) at BCL11A, HBS1L-MYB and HBB with HbF levels in 237 Kuwaiti SCD patients, divided into 3 subgroups according to their HbF levels. Illumina Ampliseq custom DNA panel was used for genotyping and confirmed by arrayed primer extension or Sanger sequencing. In the BCL11A locus, the CC genotype of rs7606173 [χ2 = 16.5] and (GG) of rs10195871 [χ2 = 15.0] were associated with Hb-F1 and HbF-2 subgroups, unlike rs1427404-T [χ2 = 17.3], which showed the highest association across the three subgroups. HBS1L-MYB locus revealed 2 previously-described SNPs (rs66650371 [χ2 = 9.5] and rs35795442 [χ2 = 9.2]) and 2 previously-unreported SNPs, (rs13220662 [χ2 = 6.2] and rs1406811 [χ2 = 6.7]) that were associated with the HbF-3 subgroup, making this the key locus elevating HbF to the highest levels. HBB cluster variants were associated with lower levels of HbF (β = −1.1). We report four previously-unpublished variants showing significant association with HbF. Each of the three quantitative trait loci affects HbF levels differently; unique SNPs, especially in HBS1L-MYB, elevate HbF to the highest levels
A regulatory pathway involving retinoic acid and calcineurin demarcates and maintains joint cells and osteoblasts in regenerating fin
During zebrafish fin regeneration, blastema cells lining the epidermis differentiate into osteoblasts and joint cells to reconstruct the segmented bony rays. We show that osteoblasts and joint cells originate from a common cell lineage, but are committed to different cell fates. Pre-osteoblasts expressing runx2a/b commit to the osteoblast lineage upon expressing sp7, whereas the strong upregulation of hoxa13a correlates with a commitment to a joint cell type. In the distal regenerate, hoxa13a, evx1 and pthlha are sequentially upregulated at regular intervals to define the newly identified presumptive joint cells. Presumptive joint cells mature into joint-forming cells, a distinct cell cluster that maintains the expression of these factors. Analysis of evx1 null mutants reveals that evx1 is acting upstream of pthlha and downstream of or in parallel with hoxa13a. Calcineurin activity, potentially through the inhibition of retinoic acid signaling, regulates evx1, pthlha and hoxa13a expression during joint formation. Furthermore, retinoic acid treatment induces osteoblast differentiation in mature joint cells, leading to ectopic bone deposition in joint regions. Overall, our data reveal a novel regulatory pathway essential for joint formation in the regenerating fin
The Prevalence of β-Thalassemia and Other Hemoglobinopathies in Kuwaiti Premarital Screening Program: An 11-Year Experience
This study aims to estimate the prevalence rates of β-thalassemia and Sickle cell disorders in the adult population screened (n = 275,819) as part of the Kuwaiti National Premarital Screening Program. All the individuals who applied for a marriage license during the years 2009 and 2020 were covered by the program. A network of four reception centers in the Ministry of Health facilities and one Premarital Diagnostic Laboratory (PDL) in Maternity Hospital were involved in performing all investigations for hemoglobinopathies. The total number of individuals identified with β-thal trait was 5861 (2.12%), while 22 individuals (0.008%) were diagnosed with β-thal disease. A total of 5003 subjects (1.81%) were carrying the Sickle cell trait, while 172 subjects (0.062%) had Sickle cell disease including Sickle cell anemia (SCA). Results showed that the program succeeded indeed in preventing the marriage of 50.4% of risky couples by issuing unsafe marriage certificates. Yet more efforts are needed to improve the program’s main objective of decreasing high-risk marriages. In particular, health care systems should be ameliorated in a way to intensify the counselling mechanism for the high-risk couples, strengthen the awareness of the general population and induce earlier age screening policies